JP2022038461A - Tire, tire pattern constitutional unit arrangement determination method, tread segment split position determination method, and tire design method - Google Patents

Abstract

To provide a tire which can achieve reduction of pitch noise and improvement of tire uniformity, and so on.SOLUTION: A tire 1 has a tread part 2. Each pattern constitutional unit 4 is so made as to be a unit pulse from a pattern row 5 of a tread pattern 3, a first pulse row, in which the unit pulses are arranged at intervals, is obtained, each parting area 17 is so made as to be a unit pulse from a parting area row 18, and a second pulse row, in which the unit pulses are arranged at intervals, is obtained. When 1st to k-th order phase ∠FAk of the first pulse row is obtained and 1st to k-th order phase ∠FBk of the second pulse row is obtained, n-th order phase difference Δ∠Fn of 1st to k-th phase differences Δ∠Fk is limited to a certain range.SELECTED DRAWING: Figure 1

Description

The present invention relates to tires and the like.

The following Patent Document 1 describes a tire having a tread pattern in which pattern constituent units are arranged in the tire circumferential direction. In this tire, the maximum value F _max of the amplitude F _k is limited to a predetermined range among the amplitudes F _k of the 1st to kth orders obtained by replacing the pulse train with a pulse train whose pattern constituent unit is a pulse and Fourier transforming the pulse train. Then, the peak of the amplitude F _k is leveled over a wide range of the order k.

JP-A-2019-99131

In recent years, there has been an increasing demand not only for reducing pitch noise but also for improving tire uniformity.

Generally, a tread mold for vulcanizing a tread portion of a tire is formed by connecting a plurality of tread segments in the tire circumferential direction. Therefore, at the split position of the tread segment, the roundness of the mold is slightly reduced, which affects the pitch noise. Furthermore, the decrease in the roundness of the mold also affects the uniformity of the tire. Therefore, in order to reduce pitch noise and improve tire uniformity, it is necessary to consider not only the tread pattern but also the influence of the split position of the tread segment.

The present invention has been devised in view of the above circumstances, and an object of the present invention is to provide a tire or the like capable of reducing pitch noise and improving tire uniformity.

ここで、
Ｎ：第１パルス列の単位パルスの個数
ｎ：第２パルス列の単位パルスの個数
Ｌ：第１パルス列の全長、又は、第２パルス列の全長
ｋ：１～Ｎまでの自然数
Ｘ（ｊ）：第１パルス列の起点からｊ番目の単位パルス位置、又は、第２パルス列の起点からｊ番目の単位パルスの位置 The present invention is a tire having a tread portion, wherein the tread portion includes a tread pattern including a pattern array in which pattern constituent units are arranged in the tire circumferential direction, and a plurality of tread segments for forming the tread pattern. It has a row of parting areas divided by parting lines formed corresponding to the split positions, and from the pattern row, each pattern constituent unit is a unit pulse having the same size, and the unit pulse is used. The first pulse trains are arranged in the order of the arrangement of the pattern constituent units and at intervals according to the length of each pattern constituent unit in the tire circumferential direction, and each parting region is obtained from the row of the parting regions. Are unit pulses having the same magnitude, and the unit pulses are arranged in the order of the arrangement of the parting regions and at intervals according to the length of each parting region in the tire circumferential direction. 1 to obtain a phase ∠F _Ak of the 1st to kth order obtained by Fourier transforming the first pulse train with the following equation (1), and Fourier transforming the second pulse train with the following equation (2) 1 When the k-th order phase ∠F _Bk is obtained, the nth-order phase difference Δ∠F _n among the 1st to kth-order phase differences Δ∠F _k obtained by the following equation (3) is −180 to It is characterized by being −120 degrees or 120 to 180 degrees.

here,
N: Number of unit pulses in the first pulse train n: Number of unit pulses in the second pulse train L: Total length of the first pulse train or total length of the second pulse train k: Natural number from 1 to N X (j): 1st The jth unit pulse position from the starting point of the pulse train, or the jth unit pulse position from the starting point of the second pulse train.

ここで、
Ｎ：第１パルス列の単位パルスの個数
ｎ：第２パルス列の単位パルスの個数
Ｌ：第１パルス列の全長、又は、第２パルス列の全長
ｋ：１～Ｎまでの自然数
Ｘ（ｊ）：第１パルス列の起点からｊ番目の単位パルス位置、又は、第２パルス列の起点からｊ番目の単位パルスの位置
Ｐ（ｊ）：第１パルス列の起点からｊ番目の単位パルスの大きさ、又は、第２パルス列の起点からｊ番目の単位パルスの大きさ The present invention is a tire having a tread portion, wherein the tread portion includes a tread pattern including a pattern array in which pattern constituent units are arranged in the tire circumferential direction, and a plurality of tread segments for forming the tread pattern. It has a row of parting areas divided by a parting line formed corresponding to the split position, and from the pattern row, each pattern constituent unit is sized according to the length in the tire circumferential direction. A first pulse train is obtained in which the unit pulses are arranged in the order of the arrangement of the pattern constituent units and at intervals according to the length of each pattern constituent unit in the tire circumferential direction, and the parting region is obtained. From the column of, each parting region is a unit pulse having a size corresponding to the length in the tire circumferential direction, and the unit pulse is arranged in the order of the parting region and the tire circumference of each parting region. A second pulse train arranged at intervals according to the length of the direction was obtained, and the first pulse train was subjected to Fourier transform by the following equation (4) to obtain a phase ∠F _Ak of the 1st to kth order obtained. When the 1st to kth-order phase ∠F _Bk obtained by Fourier transforming the two-pulse train with the following equation (5) is obtained, the 1st to kth-order phase difference Δ∠F _k obtained by the following equation (6) Among them, the nth-order phase difference Δ∠F _n is characterized by being −180 to −120 degrees or 120 to 180 degrees.

here,
N: Number of unit pulses in the first pulse train n: Number of unit pulses in the second pulse train L: Total length of the first pulse train or total length of the second pulse train k: Natural number from 1 to N X (j): 1st The jth unit pulse position from the starting point of the pulse train, or the jth unit pulse position from the starting point of the second pulse train P (j): The magnitude of the jth unit pulse from the starting point of the first pulse train, or the second The magnitude of the jth unit pulse from the starting point of the pulse train

In the tire according to the present invention, the nth-order phase difference Δ∠F _n may be −180 to −150 degrees or 150 to 180 degrees.

In the tire according to the present invention, the interval of each unit pulse of the first pulse train is the length of the pattern constituent unit corresponding to the unit pulse with respect to the median length of all the pattern constituent units. Defined by ratio, the interval between each unit pulse in the first pulse train may be 0.8-1.2.

In the tire according to the present invention, the total number of the unit pulse of the first pulse train and the unit pulse of the second pulse train may be 30 to 100.

ここで、
Ｎ：第１パルス列の単位パルスの個数
ｎ：第２パルス列の単位パルスの個数
Ｌ：第１パルス列の全長、又は、第２パルス列の全長
ｋ：１～Ｎまでの自然数
Ｘ（ｊ）：第１パルス列の起点からｊ番目の単位パルス位置、又は、第２パルス列の起点からｊ番目の単位パルスの位置 The present invention is a method for determining the arrangement of the pattern trains included in the tread pattern of a tire in the tire circumferential direction of the pattern constituent units constituting the pattern train, and the tread pattern is divided in the tire peripheral direction. It is formed by a plurality of tread segments having predetermined positions, and in the method, each pattern constituent unit is a unit pulse having the same size from the pattern train, and the unit pulse is the pattern configuration. A first pulse train was obtained in the order of the unit arrangement and at intervals according to the length of each pattern constituent unit in the tire circumferential direction, and each tread segment had the same size from the tread segment row. A second pulse train is obtained in which the unit pulses are arranged in the order of the arrangement of the tread segments and at intervals according to the length of each tread segment in the tire circumferential direction, and the first pulse train is used. The 1st to kth-order phase ∠F _Ak obtained by Fourier transforming with the following equation (7) is obtained, and the 1st to kth-order phase ∠F _Bk obtained by Fourier transforming the second pulse train with the following equation (8). When the phase difference Δ∠F _k of the 1st to kth order obtained by the following equation (9) is obtained, the phase difference Δ∠F _n of the nth order is −180 to −120 degrees or 120 to It is characterized by including a step of determining the tread so as to be 180 degrees.

here,
N: Number of unit pulses in the first pulse train n: Number of unit pulses in the second pulse train L: Total length of the first pulse train or total length of the second pulse train k: Natural number from 1 to N X (j): 1st The jth unit pulse position from the starting point of the pulse train, or the jth unit pulse position from the starting point of the second pulse train.

ここで、
Ｎ：第１パルス列の単位パルスの個数
ｎ：第２パルス列の単位パルスの個数
Ｌ：第１パルス列の全長、又は、第２パルス列の全長
ｋ：１～Ｎまでの自然数
Ｘ（ｊ）：第１パルス列の起点からｊ番目の単位パルス位置、又は、第２パルス列の起点からｊ番目の単位パルスの位置 The present invention is a method for determining the split position of the tread segment in the tire circumferential direction for a plurality of tread segments for forming a tread pattern of a tire, and the tread pattern is a tire circumference of a pattern constituent unit. The arrangement of the directions includes a predetermined pattern sequence, and in the method, from the pattern sequence, each pattern constituent unit is a unit pulse having the same size, and the unit pulse is in the order of the arrangement of the pattern constituent units. In addition, a first pulse train arranged at intervals according to the length of each pattern constituent unit in the tire circumferential direction was obtained, and from the tread segment row, each tread segment was used as a unit pulse having the same size. , A second pulse train is obtained in which the unit pulses are arranged in the order of the arrangement of the tread segments and at intervals according to the length of each tread segment in the tire circumferential direction, and the first pulse train is expressed by the following equation (10). When the 1st to kth-order phase ∠F _Ak obtained by Fourier transforming with is obtained, and the 1st to kth-order phase ∠F _Bk obtained by Fourier transforming the second pulse train with the following equation (11) is obtained. Of the 1st to kth order phase difference Δ∠F _k obtained by the following equation (12), the nth order phase difference Δ∠F _n is −180 to −120 degrees or 120 to 180 degrees. It is characterized by including a step of determining the split position.

here,
N: Number of unit pulses in the first pulse train n: Number of unit pulses in the second pulse train L: Total length of the first pulse train or total length of the second pulse train k: Natural number from 1 to N X (j): 1st The jth unit pulse position from the starting point of the pulse train, or the jth unit pulse position from the starting point of the second pulse train.

ここで、
Ｎ：第１パルス列の単位パルスの個数
ｎ：第２パルス列の単位パルスの個数
Ｌ：第１パルス列の全長、又は、第２パルス列の全長
ｋ：１～Ｎまでの自然数
Ｘ（ｊ）：第１パルス列の起点からｊ番目の単位パルス位置、又は、第２パルス列の起点からｊ番目の単位パルスの位置 The present invention is a method for designing a tire provided with a tread pattern including a pattern array in which pattern constituent units are arranged in the tire circumferential direction, and the tread pattern is a plurality of divided in the tire circumferential direction. It is formed by a tread segment, and in the method, from the pattern sequence, each pattern constituent unit is a unit pulse having the same size, and the unit pulse is arranged in the order of the pattern constituent units, and First pulse trains arranged at intervals according to the length of each pattern constituent unit in the tire circumferential direction are obtained, and from the tread segment row, each tread segment is set as a unit pulse having the same size, and the unit is described. A second pulse train in which the pulses are arranged in the order of the arrangement of the tread segments and at intervals according to the length of each tread segment in the tire circumferential direction is obtained, and the first pulse train is subjected to Fourier transform by the following equation (13). The following equation is obtained when the 1st to kth order phase _{∠F Ak} obtained by Of the 1st to kth order phase differences Δ∠F _k obtained in (15), the nth order phase difference Δ∠F _n is set to −180 to −120 degrees or 120 to 180 degrees. It is characterized by including a step of determining an arrangement of pattern constituent units and a split position of the tread segment.

here,
N: Number of unit pulses in the first pulse train n: Number of unit pulses in the second pulse train L: Total length of the first pulse train or total length of the second pulse train k: Natural number from 1 to N X (j): 1st The jth unit pulse position from the starting point of the pulse train, or the jth unit pulse position from the starting point of the second pulse train.

ここで、
Ｎ：第１パルス列の単位パルスの個数
ｎ：第２パルス列の単位パルスの個数
Ｌ：第１パルス列の全長、又は、第２パルス列の全長
ｋ：１～Ｎまでの自然数
Ｘ（ｊ）：第１パルス列の起点からｊ番目の単位パルス位置、又は、第２パルス列の起点からｊ番目の単位パルスの位置
Ｐ（ｊ）：第１パルス列の起点からｊ番目の単位パルスの大きさ、又は、第２パルス列の起点からｊ番目の単位パルスの大きさ The present invention is a method for determining the arrangement of the pattern trains included in the tread pattern of a tire in the tire circumferential direction of the pattern constituent units constituting the pattern train, and the tread pattern is divided in the tire peripheral direction. It is formed by a plurality of tread segments having predetermined positions, and in the method, each pattern constituent unit is made into a unit pulse having a size corresponding to the length in the tire circumferential direction from the pattern sequence. , The first pulse train in which the unit pulses are arranged in the order of the arrangement of the pattern constituent units and at intervals according to the length of each pattern constituent unit is obtained, and each tread segment is obtained from the row of the tread segments. A unit pulse having a size corresponding to the length in the tire circumferential direction is used, and the unit pulses are arranged in the order of the arrangement of the tread segments and at intervals according to the length of each tread segment. A two-pulse train is obtained, the first pulse train is Fourier-transformed by the following equation (16) to obtain a 1-kth-order phase ∠F _Ak , and the second pulse train is Fourier-transformed by the following equation (17). When the 1st to kth order phase ∠F _Bk is obtained, of the 1st to kth order phase difference Δ∠F _k obtained by the following equation (18), the nth order phase difference Δ∠F _n is −. It is characterized by including a step of determining the sequence so as to be 180 to −120 degrees or 120 to 180 degrees.

here,
N: Number of unit pulses in the first pulse train n: Number of unit pulses in the second pulse train L: Total length of the first pulse train or total length of the second pulse train k: Natural number from 1 to N X (j): 1st The jth unit pulse position from the starting point of the pulse train, or the jth unit pulse position from the starting point of the second pulse train P (j): The magnitude of the jth unit pulse from the starting point of the first pulse train, or the second The magnitude of the jth unit pulse from the starting point of the pulse train

ここで、
Ｎ：第１パルス列の単位パルスの個数
ｎ：第２パルス列の単位パルスの個数
Ｌ：第１パルス列の全長、又は、第２パルス列の全長
ｋ：１～Ｎまでの自然数
Ｘ（ｊ）：第１パルス列の起点からｊ番目の単位パルス位置、又は、第２パルス列の起点からｊ番目の単位パルスの位置
Ｐ（ｊ）：第１パルス列の起点からｊ番目の単位パルスの大きさ、又は、第２パルス列の起点からｊ番目の単位パルスの大きさ The present invention is a method for determining the split position of the tread segment in the tire circumferential direction for a plurality of tread segments for forming a tread pattern of a tire, and the tread pattern is a tire circumference of a pattern constituent unit. The arrangement of the directions includes a predetermined pattern sequence, and the method uses the pattern sequence to make each pattern constituent unit a unit pulse having a size corresponding to the length in the tire circumferential direction, and obtains the unit pulse. First pulse trains arranged in the order of the arrangement of the pattern constituent units and at intervals according to the length of each pattern constituent unit are obtained, and from the row of the tread segments, each tread segment is placed in the tire circumferential direction thereof. A second pulse train having a size corresponding to the length of each tread segment is obtained, and the unit pulses are arranged in the order of the arrangement of the tread segments and at intervals according to the length of each tread segment. The 1st to kth-order phase ∠F _Ak obtained by Fourier transforming the first pulse train with the following equation (19) is obtained, and the 1st to kth order obtained by Fourier transforming the second pulse train with the following equation (20). When the phase ∠F _Bk of the order ∠F Bk is obtained, of the phase difference Δ∠F _k of the 1st to kth orders obtained by the following equation (21), the phase difference Δ∠F _n of the nth order is −180 to −120 degrees. Or, it is characterized by including a step of determining the split position so as to be 120 to 180 degrees.

here,
N: Number of unit pulses in the first pulse train n: Number of unit pulses in the second pulse train L: Total length of the first pulse train or total length of the second pulse train k: Natural number from 1 to N X (j): 1st The jth unit pulse position from the starting point of the pulse train, or the jth unit pulse position from the starting point of the second pulse train P (j): The magnitude of the jth unit pulse from the starting point of the first pulse train, or the second The magnitude of the jth unit pulse from the starting point of the pulse train

ここで、
Ｎ：第１パルス列の単位パルスの個数
ｎ：第２パルス列の単位パルスの個数
Ｌ：第１パルス列の全長、又は、第２パルス列の全長
ｋ：１～Ｎまでの自然数
Ｘ（ｊ）：第１パルス列の起点からｊ番目の単位パルス位置、又は、第２パルス列の起点からｊ番目の単位パルスの位置
Ｐ（ｊ）：第１パルス列の起点からｊ番目の単位パルスの大きさ、又は、第２パルス列の起点からｊ番目の単位パルスの大きさ The present invention is a method for designing a tire provided with a tread pattern including a pattern array in which pattern constituent units are arranged in the tire circumferential direction, and the tread pattern is a plurality of divided in the tire circumferential direction. It is formed by a tread segment, and in the method, from the pattern train, each pattern constituent unit is a unit pulse having a size corresponding to the length in the tire circumferential direction, and the unit pulse is the pattern configuration. First pulse trains are obtained in the order of unit arrangement and at intervals according to the length of each pattern constituent unit, and from the tread segment row, each tread segment is lengthened in the tire circumferential direction. A second pulse train was obtained in which the unit pulses were arranged in the order of the arrangement of the tread segments and at intervals according to the length of each tread segment. The 1st to kth order phase ∠F _Ak obtained by Fourier transforming the pulse train with the following equation (22) is obtained, and the 1st to kth order phase ∠ obtained by Fourier transforming the second pulse train with the following equation (23). When F _Bk is obtained, of the 1st to kth order phase difference Δ∠F _k obtained by the following equation (24), the nth order phase difference Δ∠F _n is −180 to −120 degrees or It is characterized by including a step of determining an arrangement of the pattern constituent units and a split position of the tread segment so as to be 120 to 180 degrees.

here,
N: Number of unit pulses in the first pulse train n: Number of unit pulses in the second pulse train L: Total length of the first pulse train or total length of the second pulse train k: Natural number from 1 to N X (j): 1st The jth unit pulse position from the starting point of the pulse train, or the jth unit pulse position from the starting point of the second pulse train P (j): The magnitude of the jth unit pulse from the starting point of the first pulse train, or the second The magnitude of the jth unit pulse from the starting point of the pulse train

By adopting the above configuration, the tire of the present invention can improve uniformity while reducing pitch noise.

It is a development view which shows an example of the tread part of a tire. It is sectional drawing explaining an example of the vulcanization process of a tire. It is sectional drawing along the tire equator of the tread mold and the raw tire of FIG. It is a diagram which shows an example of the 1st pulse train. It is a diagram which shows an example of the 2nd pulse train. It is a graph which shows an example of the relationship between the amplitude F _Ak of the 1st pulse train, and the order k. It is a graph which shows an example of the nth-order phase ∠F _An of the 1st pulse train. It is a graph which shows an example of the relationship between the amplitude F _Bk of the 2nd pulse train, and the order k. It is a graph which shows the nth-order phase ∠F _Bn of the 2nd pulse train. (A) is a graph showing an example of a combined wave of phase ∠F _An and phase ∠F _Bn which are in phase with each other, and (b) is phase ∠F _An and phase ∠F _Bn when they are in opposite phase to each other. It is a graph which shows an example of the composite wave of. It is a diagram which shows an example of the 1st pulse train of another Embodiment of this invention. child It is a flowchart which shows an example of the processing procedure of the arrangement determination method of a tire pattern constituent unit. It is a flowchart which shows an example of the processing procedure of the split position determination method of a tread segment. It is a flowchart which shows an example of the processing procedure of the tire design method.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. It should be noted that each drawing is for enhancing the understanding of the content of the invention, and it is pointed out in advance that the scales and the like do not exactly match between the drawings, in addition to the exaggerated display.

FIG. 1 is a development view showing an example of a tread portion 2 of a tire 1. The tire 1 of the present embodiment has a tread portion 2. The tread portion 2 has a tread pattern 3.

The tread pattern 3 of the present embodiment is configured to include a pattern row 5 in which pattern constituent units 4 are arranged in the tire circumferential direction. The pattern row 5 is provided with at least one row (five rows in this embodiment). It is exemplified that each pattern constituent unit 4 has the same position in the tire circumferential direction as the pattern constituent unit 4 of another pattern row 5 adjacent to each other in the tire axial direction, but the position is displaced in the tire circumferential direction. It may be (out of phase).

The pattern row 5 of the present embodiment includes at least two types (five types in this example) of pattern constituent units 4 having different lengths D1 in the tire circumferential direction. The pattern row 5 may be composed of one type of pattern constituent unit 4 (not shown) having the same length D1 in the tire circumferential direction.

In the present specification, unless otherwise specified, the dimensions and the like of each part of the tire 1 are the values measured in the normal state where the tire 1 is rim-assembled on the regular rim and the tire 1 is filled with the regular internal pressure and has no load. do.

A "regular rim" is a rim defined for each tire in the standard system including the standard on which the tire 1 is based. For example, "standard rim" for JATTA and "Design Rim" for TRA. If it is ETRTO, it is "Measuring Rim".

"Regular internal pressure" is the air pressure defined for each tire in the standard system including the standard on which Tire 1 is based. For JATMA, "maximum air pressure", for TRA, the table "TIRE LOAD LIMITS". The maximum value described in "AT VARIOUS COLD INFLATION PRESSURES", or "INFLATION PRESSURE" for ETRTO.

The type of the pattern constituent unit 4 can be appropriately set according to, for example, the conditions of the vehicle on which the tire 1 is mounted and the road surface. It is desirable that the pattern constituent unit 4 has, for example, about 2 to 10 types. The case where the pattern constituent unit 4 of the present embodiment has five types (in this example, 4 _SS , 4 _S , 4 _M , 4 _L , and 4 _LL ) is exemplified.

The pattern constituent unit 4 of the present embodiment includes one block 6 and one lateral groove 7 adjacent to the block 6 on one side in the tire circumferential direction. Therefore, the case where the tread pattern 3 of the present embodiment is a block pattern is exemplified. The tread pattern 3 is not limited to the block pattern, and may be, for example, a rib pattern. The block 6 (pattern row 5) of the present embodiment is divided into a lateral groove 7 and a main groove 8 extending in a direction intersecting the lateral groove 7 and continuously extending in the tire circumferential direction.

FIG. 2 is a cross-sectional view illustrating an example of the vulcanization process of the tire 1. In the vulcanization step of the tire 1, the vulcanization die 10 is used. The vulcanization die 10 is configured to include a tread mold 11, a pair of side molds 15, a pair of bead rings 19, and a bladder 20 as in the conventional one. The vulcanization die 10 is not limited to such a configuration. For example, instead of the bladder 20, a rigid core (not shown) may be used.

In the vulcanization step of the present embodiment, for example, the bladder 20 expanded by the supply of high-pressure steam causes the unvulcanized raw tire 1L to have the molding surface 11s of the tread mold 11, the molding surface 15s of the pair of side molds 15, and the pair. It is pressed against the molding surface 19s of the bead ring 19 of the above. As a result, in the vulcanization step, the raw tire 1L can be vulcanized and molded to produce the tire 1 shown in FIG.

FIG. 3 is a cross-sectional view of the tread mold 11 and the raw tire 1L of FIG. 2 along the tire equator C. The tread mold 11 is configured to include a plurality of tread segments 12 for forming the tread pattern 3 (shown in FIG. 1). By arranging these tread segments 12 in the tire circumferential direction, the tread mold 11 is formed. The tread segment 12 is fixed to, for example, a container 14 (shown in FIG. 2).

The plurality of tread segments 12 (tread molds 11) are provided with molding surfaces 11s for forming the tread pattern 3 (shown in FIG. 1). A tread pattern 3 (shown in FIG. 1) is formed by pressing an unvulcanized raw tire 1L against these molded surfaces 11s and vulcanizing the tires.

The tread mold 11 of the present embodiment is composed of one type of tread segment 12 having the same central angle α1 (length D4 in the tire circumferential direction) with respect to the axis 26 thereof. Here, it is assumed that a fluctuation (manufacturing error) of the central angle α1 of about ± 1 degree to 3 degrees is allowed for “the same central angle α1”.

The tread mold 11 may include at least two types of tread segments 12 having different central angles α1 (length D4 in the tire circumferential direction). In this case, the type of the tread segment 12 is appropriately determined according to various restrictions such as a fixed position to the container 14 (shown in FIG. 2) and the structure of the tread segment 12 (groove forming portion or blade (not shown)). It can be set (for example, set to about 2 to 10 types).

As shown in FIG. 1, a parting line 16 is formed in the vulcanized tread portion 2 corresponding to the split position 13 (shown in FIG. 3) of the tread segment 12. As a result, the tread portion 2 is provided with a row 18 of the parting area 17 divided by the parting line 16.

The parting line 16 of the present embodiment is formed linearly along the tire axial direction, but is not limited to such an embodiment. The parting line 16 may be inclined or curved with respect to the tire axial direction, for example.

The parting region 17 can be specified as a region that is in contact with the molding surface 11s of each tread segment 12 at the time of vulcanization molding shown in FIG. The tread mold 11 of this embodiment is not divided in the tire axial direction. Therefore, as shown in FIG. 1, in the tread portion 2 of the present embodiment, a parting line (not shown) extending in the tire circumferential direction is not formed, so that only one row 18 of the parting region is provided. .. The tread portion 2 may be provided with two or more rows of parting regions (not shown).

As shown in FIG. 3, each tread segment 12 of the present embodiment is composed of one type in which the length D4 (central angle α1) in the tire circumferential direction is set to be the same. As a result, as shown in FIG. 1, the row 18 of the parting region has the same length in the tire circumferential direction (that is, the distance between the adjacent parting lines 16 and 16 in the tire circumferential direction) D2. One type of parting area 17 is included. When a plurality of types of tread segments 12 having different tire circumferential lengths D4 are configured, a plurality of types of parting regions 17 having different tire circumferential lengths D2 are arranged in the row 18 of the parting region. Is included.

The length D2 and sequence of each parting region 17 correspond to the length D4 and sequence of each tread segment 12 shown in FIG. Therefore, the row 18 of the parting area shown in FIG. 1 includes the same number of parting areas 17 as the tread segment 12 (shown in FIG. 3).

By the way, since the tread mold 11 shown in FIG. 3 is formed of a plurality of tread segments 12, the roundness of the tread mold 11 may be slightly reduced at the split position 13 of the tread segments 12. be. Such a decrease in roundness may reduce the roundness of the tread portion 2 in the parting line 16 shown in FIG. 1 within a range that does not affect the running performance.

The decrease in the roundness of the tread portion 2 affects the pitch noise as in the pattern row 5 of the tread pattern 3. Further, the decrease in the roundness of the tread portion 2 (the decrease in the roundness of the tread mold 11) also affects the uniformity of the tire 1. Therefore, in order to reduce the pitch noise and improve the uniformity of the tire 1, it is necessary to consider not only the tread pattern 3 but also the influence of the split position of the tread segment 12.

FIG. 4 is a diagram showing an example of the first pulse train 21. In FIG. 4, the vertical axis indicates the magnitude B1 of the unit pulse 24 of the first pulse train 21. On the other hand, the horizontal axis indicates the interval at which each unit pulse 24 is generated.

In the tire 1 of the present embodiment, the first pulse train 21 (shown in FIG. 4) is obtained from the pattern train 5 shown in FIG. When a plurality of pattern trains 5 are formed in the tread portion 2, the first pulse train 21 can be acquired from any pattern train 5. In this case, it is desirable that the first pulse train 21 is acquired from the pattern train 5 having a large influence on pitch noise and uniformity (for example, the pattern train 5 arranged on the tire equator C side).

In the present embodiment, each pattern constituent unit 4 (in this example, 4 _SS , 4 _S , 4 _M , 4 _L , 4 _LL ) of the pattern row 5 shown in FIG. 1 has the same size B1. It is said to be pulse 24. Then, the first pulse train 21 can be acquired by arranging these unit pulses 24 in the order of the arrangement of the pattern constituent units 4 with an interval G1. In the present embodiment, for the arrangement of the unit pulse 24, one pattern constituent unit 4 (pattern constituent unit 4 _SS in FIG. 4) is selected from the pattern row 5 shown in FIG. 1, and the selected pattern constituent unit 4 is selected. Are arranged in the order of the arrangement of the pattern constituent units 4 starting from.

The magnitude B1 of each unit pulse 24 can be appropriately set as long as they all have the same magnitude. The size B1 of this embodiment is set to 1.0, for example.

The interval G1 of each unit pulse 24 of the present embodiment is set according to the length D1 (shown in FIG. 1) of each pattern constituent unit 4 in the tire circumferential direction. Therefore, when at least two types of pattern constituent units 4 having different lengths D1 in the tire circumferential direction are included as in the pattern row 5 of the present embodiment, the arrangement of the unit pulses 24 is not evenly spaced.

The interval G1 of each unit pulse 24 is not particularly limited as long as it is set according to the length D1 (shown in FIG. 1) of each pattern constituent unit 4 in the tire circumferential direction. In the present embodiment, the interval G1 of each unit pulse 24 is the median value of the length D1 of all the pattern constituent units 4 for the length D1 of the pattern constituent unit 4 (shown in FIG. 1) corresponding to the unit pulse 24. In this example, it is defined by the ratio to (the length D1 of the pattern constituent unit 4 _M ). When the type of the pattern constituent unit 4 is an even number, the interval G1 of each unit pulse 24 may be defined as a ratio to the average value of the lengths D1 of all the pattern constituent units 4.

FIG. 5 is a diagram showing an example of the second pulse train 22. In FIG. 5, the vertical axis indicates the magnitude B2 of the unit pulse 25 of the second pulse train 22. On the other hand, the horizontal axis indicates the interval at which each unit pulse 25 is generated.

In the tire 1 of the present embodiment, the second pulse train 22 is obtained from the row 18 in the parting region shown in FIG. In the present embodiment, each parting region 17 is a unit pulse 25 having the same magnitude B2. Then, the second pulse train 22 can be acquired by arranging these unit pulses 25 in the order of the arrangement of the parting region 17 with an interval G2.

In the present embodiment, the unit pulse 25 selects one parting area 17 from the row 18 of the parting area shown in FIG. 1, and arranges the parting area 17 in the order of the arrangement of the parting area 17 as a starting point. Be done.

The magnitude B2 of each unit pulse 25 can be appropriately set as long as they all have the same magnitude. The size B2 of the present embodiment is set to be the same as the size B1 of the unit pulse 24 of the first pulse train 21 shown in FIG. 4 (for example, 1.0).

The interval G2 of each unit pulse 25 of the present embodiment is set according to the length D2 (shown in FIG. 1) of each parting region 17 in the tire circumferential direction. Therefore, when one type of parting region 17 having the same length D2 in the tire circumferential direction is included as in the row 18 of the parting region of the present embodiment, the arrangement of the unit pulses 25 is evenly spaced. Will be. When at least two types of parting regions 17 having different lengths D2 in the tire circumferential direction are included, the arrangement of each unit pulse 25 is the same as that of the first pulse train 21 (shown in FIG. 4) of the present embodiment. It will not be evenly spaced.

The interval G2 of each unit pulse 25 is not particularly limited as long as it is set according to the length D2 (shown in FIG. 1) of each parting region 17 in the tire circumferential direction. In the present embodiment, the interval G2 of each unit pulse 25 is the median value of the length D2 of all the parting regions 17 (in this example, the length) with respect to the length D2 of the parting region 17 corresponding to the unit pulse 25. It is defined by the ratio to D2). When the type of the parting region 17 is an even number, the interval G2 of each unit pulse 25 may be defined as a ratio to the average value of the lengths D2 of all the parting regions 17.

In the present embodiment, the phase ∠F _Ak of the 1st to kth order obtained by Fourier transforming the first pulse train 21 (shown in FIG. 4) by the following equation (1) is obtained.

ここで、
Ｎ：第１パルス列の単位パルスの個数
Ｌ：第１パルス列の全長
ｋ：１～Ｎまでの自然数
Ｘ（ｊ）：第１パルス列の起点からｊ番目の単位パルス位置

here,
N: Number of unit pulses in the first pulse train L: Overall length of the first pulse train k: Natural number from 1 to N X (j): Jth unit pulse position from the starting point of the first pulse train

In the above equation (1), the number N is the total number (total number) of the unit pulses 24 of the first pulse train 21 shown in FIG. Therefore, the number N is the same as the total number (total number) of the pattern constituent units 4 in one round of the tire.

The total length L (not shown) of the first pulse train 21 is obtained by summing the intervals G1 of each unit pulse 24 of the first pulse train 21 shown in FIG. The interval G1 of the present embodiment is the median value (this example) of the length D1 of all the pattern constituent units 4 with respect to the length D1 (shown in FIG. 1) of the pattern constituent unit 4 in the tire circumferential direction corresponding to the unit pulse 24. Then, it is obtained as a ratio to the length D1) of the pattern constituent unit 4 _M. Therefore, the total length L is the same as the sum of the ratios of the lengths D1 (intervals G1) for all the pattern constituent units 4 arranged over one round of the tire shown in FIG. 1, and is equivalent to one round of the tire. It is treated as representing the length of the wavelength of.

The pulse positions X (j) (j is a natural number from 1 to N) in the above equation (1) are the starting points of the first pulse train 21 (in this example, the unit pulse indicating the pattern constituent unit 4 _SS ). 24) indicates the position of the jth unit pulse 24. The pulse position X (j) is the ratio PL (j) of the interval G1 (length D1 (shown in FIG. 1)) between the unit pulses existing from the starting point to the jth unit pulse 24 and those unit pulses 24. ) Is summed up.
X (1) = PL (1)
X (2) = PL (1) + PL (2)
・
・
・
X (j) = PL (1) + PL (2) + ... + PL (j)

FIG. 6 is a graph showing an example of the relationship between the amplitude F _Ak of the first pulse train and the order k. FIG. 7 is a graph showing an example of the nth-order phase ∠F _An of the first pulse train. In FIGS. 6 and 7, the order n indicates the number of parting regions 17 shown in FIG. 1 (the number of unit pulses in the second pulse train 22).

In FIG. 6, the amplitude F _Ak is obtained by Fourier transforming the first pulse train 21 by the following equation (25). The variables and constants in the following equation (25) are the same as the variables and constants in the above equation (1).

The amplitude F _Ak is used to predict low-order components (noise energy with a low frequency in this embodiment). The amplitude F _Ak has a correlation with the magnitude of the noise energy when the pitch noise is frequency-analyzed when the tire is running. The order k has a correlation with the frequency of noise energy. The order k is set in the range from the first order to the Nth order (that is, the number of unit pulses 24 of the first pulse train (total number of pattern constituent units 4) N) as shown in the above equation (1). ..

In FIG. 7, among the 1st to kth-order phases ∠F _Ak (not shown) obtained by Fourier transforming the first pulse train 21 by the above equation (1), the n-th-order phase ∠F _An is shown as a representative. Has been done. This nth-order phase ∠F _An shows the waveform of the n-th order amplitude F _An among the first-order to k-th order amplitude F _Ak shown in FIG. In FIG. 7, a waveform of one cycle (0 to 360 degrees) is shown for the nth-order phase ∠F _An (waveform of the nth-order amplitude F _An ).

In the present embodiment, the phase ∠F _Bk of the 1st to kth order obtained by Fourier transforming the second pulse train 22 (shown in FIG. 5) by the following equation (2) is obtained.

ここで、
ｎ：第２パルス列の単位パルスの個数
Ｌ：第２パルス列の全長
ｋ：１～ｎまでの自然数
Ｘ（ｊ）：第２パルス列の起点からｊ番目の単位パルスの位置

here,
n: Number of unit pulses in the second pulse train L: Overall length of the second pulse train k: Natural number from 1 to n X (j): Position of the jth unit pulse from the starting point of the second pulse train

In the above equation (2), the number n is the total number (total number) of the unit pulses 25 of the second pulse train 22. Therefore, the number n is the same as the total number (total number) of the parting regions 17 in one round of the tire, and is the same as the number of divisions of the tread segment 12 in one round of the tire.

The total length L (not shown) of the second pulse train 22 is obtained by summing the intervals G2 of each unit pulse 25 of the second pulse train 22 shown in FIG. The interval G2 of the present embodiment is obtained as a ratio of the length D2 of the parting region 17 corresponding to the unit pulse 25 (shown in FIG. 1) to the median of the lengths D2 of all the parting regions 17. .. Therefore, the total length L is the same as the sum of the ratios of the lengths D2 (intervals G2) for all the parting regions 17 arranged over one round of the tire shown in FIG. 1, which is equivalent to one round of the tire. It is treated as representing the length of the wavelength of.

The pulse positions X (j) (j is a natural number from 1 to n) in the above equation (2) indicate the position of the j-th unit pulse 25 from the starting point of the second pulse train 22 as follows. .. This pulse position X (j) is the interval between the unit pulses existing from the starting point to the jth unit pulse 25 and the unit pulse 25, similarly to the pulse position X (j) in the above equation (1). It is obtained by summing G2 (ratio PL (j) of length D2 (shown in FIG. 1)).

FIG. 8 is a graph showing an example of the relationship between the amplitude F _Bk of the second pulse train and the order k. FIG. 9 is a graph showing the nth-th order phase ∠F _Bn of the second pulse train. In FIGS. 8 and 9, the order n indicates the number of parting regions 17 shown in FIG. 1 (the number of unit pulses in the second pulse train).

In FIG. 8, the amplitude F _Bk is obtained by Fourier transforming the second pulse train 22 by the following equation (26). The variables and constants in the following equation (26) are the same as the variables and constants in the above equation (2).

Similar to the amplitude F _Ak shown in FIG. 6, the amplitude F _Bk has a correlation with the magnitude of the noise energy when the pitch noise is frequency-analyzed during tire running. The order k has a correlation with the frequency of noise energy. The order k is set in the range from the first order to the nth order (that is, the number of unit pulses 25 of the second pulse train 22 (total number of parting regions 17) n) as shown in the above equation (2). Alternatively, it may be set in the range of an integral multiple of the 1st to nth orders (4nth order in this example).

In FIG. 9, among the 1st to kth-order phases ∠F _Bk (not shown) obtained by Fourier transforming the second pulse train 22 by the above equation (2), the n-th-order phase ∠F _Bn is shown as a representative. Has been done. This nth-th order phase ∠F _Bn shows the waveform of the nth-th order amplitude F _Bn among the first-order to k-th order amplitude F _Bk shown in FIG. In FIG. 9, for the nth-order phase ∠F _Bn (waveform of the nth-order amplitude F _Bn ), a waveform of one cycle (0 to 360 degrees) is shown.

In the tire 1 of the present embodiment, of the 1st to kth order phase difference Δ∠F _k obtained by the following equation (3), the nth order phase difference Δ∠F _n is −180 to −120 degrees or Limited to 120-180 degrees.

In the above equation (3), the phase ∠F _Ak (in FIG. 7, the nth-order phase ∠F _An is shown) obtained from the first pulse train 21 is obtained from the second pulse train 22 for each of the 1st to kth orders. It is subtracted by the phase ∠F _Bk to be obtained (in FIG. 9, the nth-order phase ∠F _Bn is shown). As a result, the phase difference Δ∠F _k (not shown) of the 1st to kth order can be obtained. FIG. 10A is a graph showing an example of a combined wave (phase ∠F _n ) of a phase ∠F _An and a phase ∠F _Bn that are in phase with each other. FIG. 10B is a graph showing an example of a combined wave (phase ∠F _n ) of phase ∠F _An and phase ∠F _Bn when they approach each other in opposite phases.

As the phase difference Δ∠F _k approaches ± 0 degrees in each of the 1st to kth orders, the phase ∠F _Ak (in FIG. 7, the nth-order phase ∠F _An is shown) and the phase ∠F _Bk ( FIG. 9 shows that the nth-order phase ∠F _Bn ) is approaching the same phase. In this way, when the phase ∠F _An and the phase ∠F _Bn approach each other in phase (the phase difference Δ∠F _k is ± 0 degrees), the phase ∠F _An and the phase ∠F _Bn amplify each other. As shown in FIG. 10A, the amplitude Fn of the combined wave of the phase ∠F _An and the phase ∠F _Bn becomes large. This causes mutual interference between the noise caused by the pattern row 5 of the tread pattern 3 shown in FIG. 1 and the noise caused by the number of divisions of the tread segment 12 (row 18 in the parting region) shown in FIG. It is shown that.

On the other hand, as the phase difference Δ∠F _k approaches ± 180 degrees, the phase ∠F _Ak (nth-order phase ∠F _An in FIG. 7) and the phase ∠F _Bk (nth-order phase ∠F in FIG. 9) _Bn ) indicates that it is approaching the opposite phase. In this way, when the phase ∠F _An and the phase ∠F _Bn approach the opposite phases (that is, the phase difference Δ∠F _k is ± 180 degrees), the phase ∠F _An and the phase ∠F _Bn cancel each other out. .. Therefore, as shown in FIG. 10B, the amplitude Fn of the combined wave of the phase ∠F _An and the phase ∠F _Bn becomes small. This reduces mutual interference between the noise caused by the pattern row 5 of the tread pattern 3 shown in FIG. 1 and the noise caused by the number of divisions of the tread segment 12 (row 18 in the parting region) shown in FIG. It shows that it is doing.

In the present embodiment, of the 1st to kth order phase differences Δ∠F _k , the nth order phase difference Δ∠Fn is limited to −180 to −120 degrees or 120 to 180 degrees. As a result, in the nth order corresponding to the number of divisions of the tread segment 12 (the number of parting regions 17), the phase ∠F _An of the first pulse train 21 (pattern row 5) and the second pulse train 22 (row of the parting region 17) It is possible to bring the phase ∠F _Bn of 18) closer to the opposite phase. Therefore, mutual interference between the noise caused by the pattern row 5 of the tread pattern 3 and the noise caused by the number of divisions of the tread segment 12 (row 18 in the parting region) can be reduced, and the pitch noise can be further reduced. It will be possible.

As shown in FIG. 4, in the first pulse train 21, each pattern constituent unit 4 is a unit pulse 24, and these unit pulses 24 are arranged in the order of the arrangement of the pattern constituent units 4 with an interval G1. Is. Therefore, the first pulse train 21 corresponds to the mass distribution of the pattern constituent unit 4 in the tire circumferential direction.

On the other hand, as shown in FIG. 5, in the second pulse train 22, the parting region 17 is set as a unit pulse 25, and these unit pulses 25 are arranged in the order of the arrangement of the parting region 17 with an interval G2. Is. Therefore, the second pulse train 22 corresponds to the mass distribution in the tire circumferential direction of the parting region 17.

In the present embodiment, the n-th order phase ∠F _An (shown in FIG. 7) of the first pulse train 21 (pattern row 5) and the nth-order phase ∠F _Bn of the second pulse train 22 (column 18 of the parting region). (Shown in FIG. 7) can be brought closer to the opposite phase. As a result, the mass distribution of the pattern constituent unit 4 and the mass distribution of the parting region 17 shown in FIG. 1 can be evenly distributed in the tire circumferential direction. Therefore, the tire 1 of the present embodiment can improve the uniformity.

As shown in FIG. 3, the tire 1 of the present embodiment is manufactured by a tread mold 11 composed of one type of tread segment 12 having the same central angle α1 (length D4 in the tire circumferential direction). .. However, in the tire 1 of the present embodiment, the phase ∠F _An shown in FIG. 7 and the phase ∠F _Bn shown in FIG. 9 can be brought close to the opposite phases, so that the pitch noise can be reduced. Therefore, the tire 1 of the present embodiment is manufactured by, for example, a tread mold 11 composed of a plurality of types of tread segments 12 having different central angles α1 (length D4 in the tire circumferential direction) in order to reduce pitch noise. Since it is not necessary to do so, the manufacturing cost can be reduced.

In order to effectively exert the above action, it is desirable that the nth-order phase difference Δ∠F _n is limited to −180 to −150 degrees or 150 to 180 degrees. When the nth-order phase difference Δ∠F _n is set to −150 degrees or less or 150 degrees or more, the phase ∠F _An of the first pulse train 21 (pattern row 5) and the second pulse train 22 (parting). The phase ∠F _Bn of the region column 18) can be more effectively brought closer to the opposite phase. As a result, the tire 1 can further improve the uniformity while further reducing the pitch noise. From this point of view, the nth-order phase difference Δ∠F _n is more preferably −180 to −160 degrees or 160 to 180 degrees.

As shown in FIG. 4, the interval G1 (in this example, the ratio of the length D1 of all the pattern constituent units 4 to the median) of each unit pulse 24 of the first pulse train 21 is 0.8 to 1.2. It is desirable to be set to. As a result, the tire 1 of the present embodiment can prevent uneven wear of the tread portion 2 while exhibiting the noise reduction effect due to the pitch variation. From this point of view, the interval G1 is preferably 0.85 or more, more preferably 0.9 or more. The size B1 and the interval G1 are preferably 1.15 or less, and more preferably 1.1 or less.

The total number of the unit pulse 24 (shown in FIG. 4) of the first pulse train 21 and the unit pulse 25 (shown in FIG. 5) of the second pulse train 22 (that is, the pattern constituent unit 4 and the parting region 17 in one round of the tire). It is desirable that the total number) is 30 to 100. By setting the total number to 30 or more, it becomes possible to effectively exert the noise reduction effect due to the pitch variation. Therefore, the total number is preferably 35 or more, and more preferably 40 or more. On the other hand, by setting the total number to 100 or less, it is possible to prevent uneven wear of the tread portion 2 and an increase in the manufacturing cost of the tread segment 12. Therefore, the total number is preferably 90 or less, more preferably 80 or less.

In the embodiments so far, the unit pulse 24 of the first pulse train 21 shown in FIG. 4 is assumed to have the same magnitude B1, and the unit pulse 25 of the second pulse train 22 shown in FIG. 5 is any of the same. Also had the same size B2, but is not limited to such an embodiment. FIG. 11 is a diagram showing an example of the first pulse train 21 according to another embodiment of the present invention. In this embodiment, the same configurations as those in the previous embodiments are designated by the same reference numerals, and the description thereof may be omitted.

The first pulse train 21 of this embodiment is a unit in which each pattern constituent unit 4 of the pattern train 5 shown in FIG. 1 has a size B1 corresponding to their tire circumferential length D1 (shown in FIG. 1). It is said to be pulse 24. Therefore, as in the pattern row 5 shown in FIG. 1, when at least two types of pattern constituent units 4 having different lengths D1 in the tire circumferential direction are included, the first pulse train 21 contains at least two types of sizes B1. The unit pulse 24 having is included.

In this embodiment, as in the previous embodiments, the unit pulses 24 are arranged in the order of the arrangement of the pattern constituent units 4 and with an interval G1 corresponding to the length D1 of each pattern constituent unit 4. As a result, the first pulse train 21 shown in FIG. 11 can be acquired.

The magnitude B1 and the interval G1 of each unit pulse 24 of the first pulse train 21 are not particularly limited as long as they are set according to the length D1 in the tire circumferential direction of each pattern constituent unit 4 shown in FIG. In this embodiment, the size B1 and the interval G1 of each unit pulse 24 are the lengths of all the pattern constituent units 4 for the length D1 (shown in FIG. 1) of the pattern constituent unit 4 corresponding to the unit pulse 24. It is defined as the ratio of D1 to the median (length D1 of pattern building unit 4 _M ). When the type of the pattern constituent unit 4 is an even number, the size B1 and the interval G1 of each unit pulse 24 may be defined by the ratio to the average value of the lengths of all the pattern constituent units 4.

In the second pulse train 22 of this embodiment, each parting region 17 of the row 18 of the parting region shown in FIG. 1 has a size B2 corresponding to the length D2 (shown in FIG. 2) in the tire circumferential direction. It is said that the unit pulse 25 has. Therefore, when one type of parting region 17 having the same length D2 in the tire circumferential direction is included as in the row 18 of the parting region of this embodiment, the second pulse train 22 shown in FIG. 5 is included. Similarly, the magnitude B2 of each unit pulse 25 is the same. On the other hand, when at least two types of parting regions 17 having different lengths D2 in the tire circumferential direction are included, a unit pulse 25 (not shown) having at least two types of sizes B2 is included.

In this embodiment, as in the previous embodiments, the unit pulses 25 are arranged in the order of the arrangement of the parting regions 17 and at intervals G2 according to the length D2 of each parting region 17. As a result, the second pulse train 22 can be acquired.

The magnitude B2 and the interval G2 of each unit pulse 25 are not particularly limited as long as they are set according to the length D2 in the tire circumferential direction of each parting region 17. In this embodiment, the magnitude B2 and the interval G2 of each unit pulse 25 are the lengths of all the parting regions 17 with respect to the length D2 (shown in FIG. 1) of the parting region 17 corresponding to the unit pulse 25. It is defined as the ratio of D2 to the median. When the type of the parting region 17 is an even number, the magnitude B2 and the interval G2 of each unit pulse 25 may be defined by the ratio to the average value of the lengths of all the parting regions 17.

In the present embodiment, the phase ∠F _Ak of the 1st to kth order obtained by Fourier transforming the first pulse train 21 (shown in FIG. 11) by the following equation (4) is obtained.

ここで、
Ｎ：第１パルス列の単位パルスの個数
Ｌ：第１パルス列の全長
ｋ：１～Ｎまでの自然数
Ｘ（ｊ）：第１パルス列の起点からｊ番目の単位パルス位置
Ｐ（ｊ）：第１パルス列の起点からｊ番目の単位パルスの大きさ

here,
N: Number of unit pulses in the first pulse train L: Total length of the first pulse train k: Natural number from 1 to N X (j): Jth unit pulse position from the starting point of the first pulse train P (j): First pulse train The magnitude of the jth unit pulse from the starting point of

In the above equation (4), the variables and constants other than the magnitude P (j) are the same as the constants and variables in the above equation (1). The magnitude P (j) (j is a natural number from 1 to N) in the above equation (4) is the jth from the starting point of the first pulse train 21 (in this example, the unit pulse 24 indicating the pattern constituent unit 4 _SS ). It shows the magnitude B1 of the unit pulse 24 of. In this embodiment, unlike the phase ∠F _Ak (in FIG. 7, the phase ∠F _An is shown) of the previous embodiments, the size B1 of the unit pulse 24 of the first pulse train 21 (the size of the pattern configuration unit 4). The phase ∠F _Ak (not shown) of the 1st to kth order considering the above) is acquired.

In the tire 1 of this embodiment, the phase ∠F _Bk of the 1st to kth order obtained by Fourier transforming the second pulse train 22 (shown in FIG. 5) by the following equation (5) is obtained.

ここで、
ｎ：第２パルス列の単位パルスの個数
Ｌ：第２パルス列の全長
ｋ：１～Ｎまでの自然数
Ｘ（ｊ）：第２パルス列の起点からｊ番目の単位パルスの位置
Ｐ（ｊ）：第２パルス列の起点からｊ番目の単位パルスの大きさ

here,
n: Number of unit pulses in the second pulse train L: Total length of the second pulse train k: Natural number from 1 to N X (j): Position of the jth unit pulse from the starting point of the second pulse train P (j): Second The magnitude of the jth unit pulse from the starting point of the pulse train

In the above equation (5), the variables and constants other than the magnitude P (j) are the same as the constants and variables in the above equation (2). The magnitude P (j) (j is a natural number from 1 to N) in the above equation (5) indicates the magnitude B2 of the jth unit pulse 25 from the starting point of the second pulse train 22. When a plurality of types of parting regions 17 are included, the size of the unit pulse 25 of the second pulse train 22 is different from the phase ∠F _Bk of the previous embodiments (in FIG. 9, the phase ∠F _Bn is shown). The phase ∠F _Bk considering B2 (the size of the parting region 17) is acquired.

In the present embodiment, of the 1st to kth order phase difference Δ∠F _k obtained by the following equation (6), the nth order phase difference Δ∠F _n is −180 to −120 degrees or 120 to 180 degrees. Limited to degrees.

In the above equation (6), the phase ∠F _Ak obtained from the first pulse train 21 is subtracted by the phase ∠F _Bk obtained from the second pulse train 22 for each of the 1st to kth orders. As a result, the phase difference Δ∠F _k of the 1st to kth order can be obtained.

In this embodiment, of the 1st to kth order phase differences Δ∠F _k , the nth order phase difference Δ∠Fn is limited to −180 to −120 degrees or 120 to 180 degrees. As a result, in the nth order corresponding to the number of divisions of the tread segment 12 (the number of parting regions 17), the phase ∠F _An of the first pulse train 21 (pattern row 5) and the second pulse train 22 (row of the parting region 17) It is possible to bring the phase ∠F _Bn of 18) closer to the opposite phase. Therefore, mutual interference between the noise caused by the pattern row 5 of the tread pattern 3 and the noise caused by the number of divisions of the tread segment 12 (row 18 in the parting region) can be reduced, and the pitch noise can be further reduced. It will be possible.

In this embodiment, the n-th-order phase ∠F _An of the first pulse train 21 (pattern row 5) and the n-th-order phase ∠F _Bn of the second pulse train 22 (parting region row 18) are brought close to opposite phases. be able to. As a result, in the tire 1 of this embodiment, the mass distribution of the pattern constituent unit 4 and the mass distribution of the parting region 17 can be evenly distributed in the tire circumferential direction, so that the uniformity can be improved.

Even if the tire 1 of this embodiment is manufactured by a tread mold 11 composed of one type of tread segment 12 having the same central angle α1 (length D4 in the tire circumferential direction), it has a phase ∠F _An and a phase. ∠F _Bn can be brought closer to the opposite phase. Therefore, the tire 1 of this embodiment can reduce the manufacturing cost while reducing the pitch noise as in the previous embodiments.

In order to effectively exert the above action, the nth-order phase difference Δ∠F _n and the interval G1 of each unit pulse 24 of the first pulse train 21 shown in FIG. 11 are the same as those in the previous embodiments. It is desirable to set it in the range of. Further, the total number of the unit pulse 24 (shown in FIG. 11) of the first pulse train 21 and the unit pulse 25 (shown in FIG. 5) of the second pulse train 22 is set in the same range as in the previous embodiments. Is desirable. Further, the magnitude B1 of each unit pulse 24 of the first pulse train 21 shown in FIG. 11 is set to the same range as the interval G1 of each unit pulse 24 of the first pulse train 21 of the previous embodiment. desirable.

Next, with respect to the pattern row 5 included in the tread pattern 3 shown in FIG. 1, a method of determining the arrangement of the pattern constituent units 4 constituting the pattern row 5 in the tire circumferential direction (hereinafter, simply referred to as "arrangement determination method"). There is.) Is explained. As described above, the tread pattern 3 is formed by a plurality of tread segments 12 in which the split positions 13 in the tire circumferential direction shown in FIG. 3 are predetermined.

In this arrangement determination method, the arrangement of the pattern constituent unit 4 in the tire circumferential direction is determined with respect to the predetermined split position 13 (parting line 16 in FIG. 1) of the tread segment 12 shown in FIG. In the sequencing method of this embodiment, for example, a known computer (not shown) is used.

FIG. 12 is a flowchart showing an example of a processing procedure of a method for determining an arrangement of tire pattern constituent units. In this embodiment, the same configurations as those in the previous embodiments are designated by the same reference numerals, and the description thereof may be omitted.

In the arrangement determination method of this embodiment, first, the split position 13 of the tread segment 12 shown in FIG. 3 in the tire circumferential direction is determined (step S1). The split position 13 can be appropriately determined. Generally, the tread mold 11 has a region that cannot be divided in the tire circumferential direction due to various restrictions such as a fixed position to the container 14 (shown in FIG. 2) and the structure of the tread segment 12 (groove forming portion and blade (not shown)). (Hereinafter, it may be simply referred to as "indivisible area".). In step S1 of this embodiment, the split position 13 of the tread segment 12 is determined in the region excluding the indivisible region (not shown) of the tread mold 11. The split position 13 is determined based on, for example, the design data (for example, CAD data) of the tread mold 11.

Next, in the arrangement determination method of this embodiment, with respect to the pattern row 5 included in the tread pattern 3 of the tire 1 shown in FIG. 1, the arrangement of the pattern constituent units 4 constituting the pattern row 5 in the tire circumferential direction is tentatively determined. (Step S2). In step S2 of this embodiment, the arrangement (pattern row 5) of the pattern constituent unit 4 is tentatively determined for the plurality of tread segments 12 (shown in FIG. 3) specified from the split positions 13 determined in step S1. Will be done. Such a tentative determination of the pattern sequence 5 can be made based on the design data (for example, CAD data) of the tread mold 11.

Next, in the sequence determination method of this embodiment, the first pulse train 21 (shown in FIG. 4 as an example) is acquired from the tentatively determined pattern train 5 (shown in FIG. 1 as an example) (step S3). .. As shown in FIG. 4, in this embodiment, each pattern constituent unit 4 (shown in FIG. 1) of the pattern sequence 5 tentatively determined in step S2 is a unit pulse 24 having the same magnitude B1. ing. Then, the first pulse train 21 can be acquired by arranging these unit pulses 24 in the order of the arrangement of the pattern constituent units 4 with an interval G1. The interval G1 of each unit pulse 24 is set according to the length D1 (shown in FIG. 1) of each pattern constituent unit 4 in the tire circumferential direction, as in the previous embodiments.

Next, in the sequence determination method of this embodiment, the second pulse train 22 (shown in FIG. 5 as an example) is acquired from the row 30 (shown in FIG. 3) of the tread segment (step S4). As shown in FIG. 5, in this embodiment, each tread segment 12 (shown in FIG. 3) whose split position 13 is determined in step S1 is a unit pulse 25 having the same magnitude B2. .. Then, the second pulse train 22 can be acquired by arranging these unit pulses 25 in the order of the arrangement of the tread segments 12 with an interval G2. The length D4 and arrangement of each tread segment 12 shown in FIG. 3 correspond to the length D2 and arrangement of each parting region 17 shown in FIG. 1 in the tire circumferential direction. The interval G2 of each unit pulse 25 is set according to the length D4 in the tire circumferential direction of each tread segment 12 shown in FIG. 3, as in the conventional embodiment.

Next, in the sequence determination method of this embodiment, the phase ∠F _Ak of the 1st to kth order obtained by Fourier transforming the first pulse train 21 by the following equation (7) is acquired (step S5). The following formula (7) is the same as the above formula (1). The details of the phase ∠F _Ak (FIG. 7 shows an example of the nth-order phase ∠F _An ) are as described above.

ここで、
Ｎ：第１パルス列の単位パルスの個数
Ｌ：第１パルス列の全長
ｋ：１～Ｎまでの自然数
Ｘ（ｊ）：第１パルス列の起点からｊ番目の単位パルス位置

here,
N: Number of unit pulses in the first pulse train L: Overall length of the first pulse train k: Natural number from 1 to N X (j): Jth unit pulse position from the starting point of the first pulse train

Next, in the sequence determination method of this embodiment, the phase ∠F _Bk of the 1st to kth order obtained by Fourier transforming the second pulse train 22 by the following equation (8) is obtained (step S6). The following formula (8) is the same as the above formula (2). The details of the phase ∠F _Bk (FIG. 9 shows an example of the nth-order phase ∠F _Bn ) are as described above.

ここで、
ｎ：第２パルス列の単位パルスの個数
Ｌ：第２パルス列の全長
ｋ：１～Ｎまでの自然数
Ｘ（ｊ）：第２パルス列の起点からｊ番目の単位パルスの位置

here,
n: Number of unit pulses in the second pulse train L: Overall length of the second pulse train k: Natural number from 1 to N X (j): Position of the jth unit pulse from the starting point of the second pulse train

Next, in the sequence determination method of this embodiment, of the 1st to kth order phase difference Δ∠F _k obtained by the following equation (9), the nth order phase difference Δ∠ corresponding to the number of divisions of the tread segment 12 It is determined whether or not F _n is −180 to −120 degrees or 120 to 180 degrees (step S7). The following formula (9) is the same as the above formula (3). The details of the 1st to kth order phase difference Δ∠F _k and the nth order phase difference Δ∠F _n are as described above.

When it is determined that the nth-order phase difference Δ∠F _n is within the above range (“Y” in step S7), the phase ∠F _An of the first pulse train 21 (pattern train 5) (shown in FIG. 7). And the phase ∠F _Bn (shown in FIG. 9) of the second pulse train 22 (row 30 of the tread segment) is approaching the opposite phase. In such a case, mutual interference between the noise caused by the pattern row 5 of the tread pattern 3 and the noise caused by the number of divisions of the tread segment 12 can be reduced, and the pitch noise can be further reduced. Therefore, the arrangement of the pattern constituent unit 4 tentatively determined in the step S2 is determined (adopted) as the arrangement of the pattern constituent unit 4 of the pattern row 5 (step S8).

On the other hand, when it is determined that the nth-order phase difference Δ∠F _n is out of the above range (“N” in step S7), the phase ∠F _An of the first pulse train 21 (pattern train 5) (shown in FIG. 7). And the phase ∠F _Bn (shown in FIG. 9) of the second pulse train 22 (the row 30 of the tread segment) does not approach the opposite phase. Therefore, it is judged that there is room for improvement in the tentatively determined arrangement of the pattern constituent units 4. In this case, the step S2 for tentatively determining the arrangement of the pattern constituent unit 4 is carried out again, and the steps S3 to S7 are carried out again. In step S2, it is desirable that a new arrangement is determined so as not to overlap with the arrangement of the pattern constituent unit 4 previously tentatively determined.

As described above, in the sequence determination method of this embodiment, of the 1st to kth order phase difference Δ∠F _k , the nth order phase difference Δ∠F _n is −180 to −120 degrees or 120 to 180 degrees. The arrangement of the pattern constituent units 4 (shown in FIG. 1) is determined so as to be the degree. Therefore, in the arrangement determination method, it is possible to reliably determine the arrangement of the pattern constituent unit 4 that can improve the uniformity while reducing the pitch noise.

In order to reliably determine the arrangement of the pattern constituent units 4 that can further improve the uniformity while further reducing the pitch noise, in step S7, the nth-order phase difference Δ∠F _n is −180 to −150 degrees. Or, it is desirable to determine whether or not the temperature is 150 to 180 degrees. More preferably, it is desirable to determine whether or not the temperature is −180 to −160 degrees or 160 to 180 degrees.

Further, in step S7, the interval G1 of each unit pulse 24 of the first pulse train 21 shown in FIG. 4 (in this example, the ratio of the length D1 of all the pattern constituent units 4 to the median value) is 0.8 to It may be determined whether or not it is set to 1.2. This makes it possible to determine the arrangement of the pattern constituent units 4 that can prevent uneven wear of the tread portion 2 while exhibiting the noise reduction effect due to the pitch variation.

Further, in step S7, whether or not the total number of the unit pulse 24 (shown in FIG. 4) of the first pulse train 21 and the unit pulse 25 (shown in FIG. 5) of the second pulse train 22 is 30 to 100. It may be judged. This makes it possible to determine the arrangement of the pattern constituent units 4 that can prevent uneven wear of the tread portion 2 and an increase in the manufacturing cost of the tread segment 12 while exhibiting the noise reduction effect.

In the sequence determination method of this embodiment, the unit pulse 24 (shown in FIG. 4) of the first pulse train 21 all has the same magnitude B1 and the unit pulse 25 (shown in FIG. 5) of the second pulse train 22. All have the same size B2, but are not limited to such an embodiment. In this embodiment, the same configurations as those in the previous embodiments are designated by the same reference numerals, and the description thereof may be omitted.

In step S3 of this embodiment, as shown in FIG. 11, each pattern constituent unit 4 of the pattern train 5 shown in FIG. 1 has a size B1 corresponding to the length D1 in the tire circumferential direction. The first pulse train 21 as the pulse 24 is acquired. The size B1 is defined by the same procedure as in the previous embodiments.

In step S4 of this embodiment, each tread segment 12 of the tread segment row 30 shown in FIG. 3 is a second pulse train having a unit pulse 25 having a size B2 corresponding to the length D4 in the tire circumferential direction. 22 (shown in FIG. 5) is acquired. The size B2 is defined by the same procedure as in the previous embodiments.

In step S5 of this embodiment, the phase ∠F _Ak of the 1st to kth order obtained by Fourier transforming the first pulse train 21 shown in FIG. 11 by the following equation (16) is acquired. The following formula (16) is the same as the above formula (4). The details of the phase ∠F _Ak are as described above.

ここで、
Ｎ：第１パルス列の単位パルスの個数
Ｌ：第１パルス列の全長
ｋ：１～Ｎまでの自然数
Ｘ（ｊ）：第１パルス列の起点からｊ番目の単位パルス位置
Ｐ（ｊ）：第１パルス列の起点からｊ番目の単位パルスの大きさ

here,
N: Number of unit pulses in the first pulse train L: Total length of the first pulse train k: Natural number from 1 to N X (j): Jth unit pulse position from the starting point of the first pulse train P (j): First pulse train The magnitude of the jth unit pulse from the starting point of

In step S6 of this embodiment, the phase ∠F _Bk of the 1st to kth order obtained by Fourier transforming the second pulse train 22 shown in FIG. 5 by the following equation (17) is acquired. The following formula (16) is the same as the above formula (5). The details of the phase ∠F _Bk are as described above.

ここで、
ｎ：第２パルス列の単位パルスの個数
Ｌ：第２パルス列の全長
ｋ：１～Ｎまでの自然数
Ｘ（ｊ）：第２パルス列の起点からｊ番目の単位パルスの位置
Ｐ（ｊ）：第２パルス列の起点からｊ番目の単位パルスの大きさ

here,
n: Number of unit pulses in the second pulse train L: Total length of the second pulse train k: Natural number from 1 to N X (j): Position of the jth unit pulse from the starting point of the second pulse train P (j): Second The magnitude of the jth unit pulse from the starting point of the pulse train

Next, in step S7 of this embodiment, of the 1st to kth order phase difference Δ∠F _k obtained by the following equation (18), the nth order phase difference Δ∠F corresponding to the number of divisions of the tread segment 12 It is determined whether _n is −180 to −120 degrees or 120 to 180 degrees. The following formula (18) is the same as the above formula (6). The details of the 1st to kth order phase difference Δ∠F _k and the nth order phase difference Δ∠F _n are as described above.

In step S7 of this embodiment, when it is determined that the nth-order phase difference Δ∠F _n is within the above range (“Y” in step S7), the pattern constituent unit 4 tentatively determined in step S2. The arrangement (shown in FIG. 1) is determined (adopted) as the arrangement of the pattern constituent unit 4 of the pattern sequence 5 (step S8). Thereby, in the arrangement determination method of this embodiment, similarly to the arrangement determination method of the previous embodiment, the arrangement of the pattern constituent units 4 capable of improving the uniformity while reducing the pitch noise is surely determined. Can be done.

In step S7, in order to reliably determine the arrangement of the pattern constituent unit 4 that can further improve the uniformity while further reducing the pitch noise, the nth-order phase difference Δ∠F _n is the arrangement determination of the previous embodiment. It is desirable to determine whether it is in the same range as the method. Further, in step S7, the size B1 and the interval G1 of each unit pulse 24 of the first pulse train 21 shown in FIG. 11 (in this example, the ratio of the length D1 of all the pattern constituent units 4 to the median value) are determined. It may be determined whether or not it is set to 0.8 to 1.2. Further, in step S7, whether or not the total number of the unit pulse 24 (shown in FIG. 11) of the first pulse train 21 and the unit pulse 25 (shown in FIG. 5) of the second pulse train 22 is 30 to 100. It may be judged.

Next, for a plurality of tread segments 12 (shown in FIG. 3) for forming the tread pattern of the tire 1, a method for determining the split position 13 of the tread segment 12 in the tire circumferential direction (hereinafter, simply "split position"). It may be called "decision method".) Is explained. In this split position determination method, the split position 13 of the tread segment 12 shown in FIG. 3 is determined with respect to the pattern row 5 in which the arrangement of the pattern constituent units 4 in the tire circumferential direction shown in FIG. 1 is predetermined. .. In the split position determining method of this embodiment, for example, a known computer (not shown) is used.

FIG. 13 is a flowchart showing an example of a processing procedure of a method for determining a split position of a tread segment. In this embodiment, the same configurations as those in the previous embodiments are designated by the same reference numerals, and the description thereof may be omitted.

In the split position determination method of this embodiment, first, for the pattern row 5 included in the tread pattern 3 of the tire 1 shown in FIG. 1, the arrangement of the pattern constituent units 4 constituting the pattern row 5 in the tire circumferential direction is determined. (Step S11). The arrangement of the pattern building blocks 4 can be determined, for example, based on the category of the tire 1 or the predetermined tread pattern 3. The pattern sequence 5 is determined based on the design data (for example, CAD data) of the tread mold 11.

Next, in the split position determination method of this embodiment, the split position 13 of the tread segment 12 shown in FIG. 3 in the tire circumferential direction is tentatively determined (step S12). In step S12 of this embodiment, the split position 13 of the tread segment 12 (arrangement of the tread segment 12) is relative to the pattern row 5 (shown in FIG. 1) specified from the arrangement of the pattern constituent unit 4 determined in step S11. ) Is tentatively decided. In step S12, the split positions 13 are determined in the regions excluding the indivisible region (not shown) of the tread mold 11. Such a tentative determination of the split position 13 is made based on, for example, the design data (for example, CAD data) of the tread mold 11.

Next, in the split position determination method of this embodiment, the first pulse train 21 (shown in FIG. 4) is acquired from the pattern train 5 (shown in FIG. 1) (step S13). As shown in FIG. 4, in this embodiment, each pattern constituent unit 4 (shown in FIG. 1) of the pattern sequence 5 determined in step S11 is a unit pulse 24 having the same magnitude B1. There is. Then, the first pulse train 21 can be acquired by arranging these unit pulses 24 in the order of the arrangement of the pattern constituent units 4 with an interval G1. The interval G1 of each unit pulse 24 is set according to the length D1 (shown in FIG. 1) of each pattern constituent unit 4 in the tire circumferential direction, as in the previous embodiments. The first pulse train 21 can be acquired based on the same procedure as the above-mentioned sequencing method.

Next, in the split position determination method of this embodiment, the second pulse train 22 (shown in FIG. 5) is acquired from the tread segment row 30 (shown in FIG. 3) (step S14). As shown in FIG. 5, in this embodiment, each tread segment 12 (shown in FIG. 3) whose split position 13 is tentatively determined in step S12 is a unit pulse 25 having the same magnitude B2. There is. Then, the second pulse train 22 can be acquired by arranging these unit pulses 25 in the order of the arrangement of the tread segments 12 with an interval G2. The length D4 and arrangement of each tread segment 12 shown in FIG. 3 correspond to the length D2 and arrangement of each parting region 17 shown in FIG. 1 in the tire circumferential direction. The interval G2 of each unit pulse 25 is set according to the length D4 in the tire circumferential direction of each tread segment 12 shown in FIG. 3, as in the conventional embodiment. The second pulse train 22 can be obtained based on the same procedure as the above-mentioned sequencing method.

Next, in the split position determination method of this embodiment, the phase ∠F _Ak of the 1st to kth order obtained by Fourier transforming the first pulse train 21 shown in FIG. 4 by the following equation (10) is acquired ( Step S15). The following formula (10) is the same as the above formula (1). The details of the phase ∠F _Ak (in FIG. 7, the nth-order phase ∠F _An is shown) are as described above.

ここで、
Ｎ：第１パルス列の単位パルスの個数
Ｌ：第１パルス列の全長
ｋ：１～Ｎまでの自然数
Ｘ（ｊ）：第１パルス列の起点からｊ番目の単位パルス位置

here,
N: Number of unit pulses in the first pulse train L: Overall length of the first pulse train k: Natural number from 1 to N X (j): Jth unit pulse position from the starting point of the first pulse train

Next, in the split position determination method of this embodiment, the phase ∠F _Bk of the 1st to kth order obtained by Fourier transforming the second pulse train 22 shown in FIG. 5 by the following equation (11) is acquired ( Step S16). The following formula (11) is the same as the above formula (2). The details of the phase ∠F _Bk (in FIG. 9, the nth-order phase ∠F _Bn is shown) are as described above.

ここで、
ｎ：第２パルス列の単位パルスの個数
Ｌ：第２パルス列の全長
ｋ：１～Ｎまでの自然数
Ｘ（ｊ）：第２パルス列の起点からｊ番目の単位パルスの位置

here,
n: Number of unit pulses in the second pulse train L: Overall length of the second pulse train k: Natural number from 1 to N X (j): Position of the jth unit pulse from the starting point of the second pulse train

Next, in the split position determination method of this embodiment, of the 1st to kth order phase difference Δ∠F _k obtained by the following equation (12), the nth order phase difference Δ corresponding to the number of divisions of the tread segment 12 It is determined whether or not ∠F _n is −180 to −120 degrees or 120 to 180 degrees (step S17). The following formula (12) is the same as the above formula (3). The details of the 1st to kth order phase difference Δ∠F _k and the nth order phase difference Δ∠F _n are as described above.

When it is determined that the nth-order phase difference Δ∠F _n is within the above range (“Y” in step S17), the phase ∠F _An of the first pulse train 21 (pattern train 5) (shown in FIG. 7). And the phase ∠F _Bn (shown in FIG. 9) of the second pulse train 22 (row 30 of the tread segment) is approaching the opposite phase. In such a case, mutual interference between the noise caused by the pattern row 5 of the tread pattern 3 and the noise caused by the number of divisions of the tread segment 12 can be reduced, and the pitch noise can be further reduced. Therefore, the split position 13 tentatively determined in step S12 is determined (adopted) as the split position 13 of the tread segment 12 (step S18).

On the other hand, when it is determined that the nth-order phase difference Δ∠F _n is out of the above range (“N” in step S17), the phase ∠F _An of the first pulse train 21 (pattern train 5) and the first phase difference ΔF An. The phase ∠F _Bn of the two-pulse train 22 (the row 30 of the tread segment) does not approach the opposite phase. Therefore, it is determined that there is room for improvement at the split position 13 (shown in FIG. 3) of the tentatively determined tread segment 12. In this case, the step S12 for tentatively determining the split position 13 is carried out again, and the steps S13 to S17 are carried out again. In step S12, it is desirable that a new split position 13 is determined so as not to overlap with the previously tentatively determined split position 13 (row of the tread segment 30).

As described above, in the split position determination method of this embodiment, of the 1st to kth order phase differences Δ∠F _k , the nth order phase difference Δ∠F _n is −180 to −120 degrees or 120 to The split position 13 (shown in FIG. 3) of the tread segment 12 is determined so as to be 180 degrees. Therefore, in the split position determination method, the split position 13 of the tread segment 12, which can improve uniformity while reducing pitch noise, can be reliably determined.

In step S17, in order to reliably determine the split position 13 (shown in FIG. 3) that can further improve uniformity while further reducing pitch noise, the nth-order phase difference Δ∠F _n is −180 to It is desirable to determine whether it is -150 degrees or 150-180 degrees. More preferably, it is desirable to determine whether or not the temperature is −180 to −160 degrees or 160 to 180 degrees.

Further, in step S17, whether or not the total number of the unit pulse 24 (shown in FIG. 4) of the first pulse train 21 and the unit pulse 25 (shown in FIG. 5) of the second pulse train 22 is 30 to 100. It may be judged. This makes it possible to determine the split position 13 of the tread segment 12 that can prevent uneven wear of the tread portion 2 and an increase in the manufacturing cost of the tread segment 12 while exhibiting the noise reduction effect.

In the split position determination method of this embodiment, the unit pulse 24 (shown in FIG. 4) of the first pulse train 21 all has the same magnitude B1 and the unit pulse 25 (shown in FIG. 5) of the second pulse train 22. ) Have the same size B2, but are not limited to such an embodiment. In this embodiment, the same configurations as those in the previous embodiments are designated by the same reference numerals, and the description thereof may be omitted.

In step S13 of this embodiment, as shown in FIG. 11, each pattern constituent unit 4 of the pattern train 5 shown in FIG. 1 has a size B1 corresponding to the length D1 in the tire circumferential direction. The first pulse train 21 as the pulse 24 is acquired. The size B1 is defined by the same procedure as in the previous embodiments.

In step S14 of this embodiment, each tread segment 12 of the tread segment row 30 shown in FIG. 3 is a second pulse train having a unit pulse 25 having a size B2 corresponding to the length D4 in the tire circumferential direction. 22 (shown in FIG. 5) is acquired. The size B2 is defined by the same procedure as in the previous embodiments.

In step S15 of this embodiment, the phase ∠F _Ak of the 1st to kth order obtained by Fourier transforming the first pulse train 21 shown in FIG. 11 by the following equation (19) is acquired. The following formula (19) is the same as the above formula (4). The details of the phase ∠F _Ak are as described above.

ここで、
Ｎ：第１パルス列の単位パルスの個数
Ｌ：第１パルス列の全長
ｋ：１～Ｎまでの自然数
Ｘ（ｊ）：第１パルス列の起点からｊ番目の単位パルス位置
Ｐ（ｊ）：第１パルス列の起点からｊ番目の単位パルスの大きさ

here,
N: Number of unit pulses in the first pulse train L: Total length of the first pulse train k: Natural number from 1 to N X (j): Jth unit pulse position from the starting point of the first pulse train P (j): First pulse train The magnitude of the jth unit pulse from the starting point of

In step S16 of this embodiment, the phase ∠F _Bk of the 1st to kth order obtained by Fourier transforming the second pulse train 22 shown in FIG. 5 by the following equation (20) is acquired. The following formula (20) is the same as the above formula (5). The details of the phase ∠F _Bk are as described above.

ここで、
ｎ：第２パルス列の単位パルスの個数
Ｌ：第２パルス列の全長
ｋ：１～Ｎまでの自然数
Ｘ（ｊ）：第２パルス列の起点からｊ番目の単位パルスの位置
Ｐ（ｊ）：第２パルス列の起点からｊ番目の単位パルスの大きさ

here,
n: Number of unit pulses in the second pulse train L: Total length of the second pulse train k: Natural number from 1 to N X (j): Position of the jth unit pulse from the starting point of the second pulse train P (j): Second The magnitude of the jth unit pulse from the starting point of the pulse train

Next, in step S17 of this embodiment, of the 1st to kth order phase difference Δ∠F _k obtained by the following equation (21), the nth order phase difference Δ∠F corresponding to the number of divisions of the tread segment 12 It is determined whether _n is −180 to −120 degrees or 120 to 180 degrees. The following formula (21) is the same as the above formula (6). The details of the 1st to kth order phase difference Δ∠F _k and the nth order phase difference ΔF are as described above.

When it is determined in step S17 that the nth-order phase difference Δ∠F _n is within the above range (“Y” in step S17), the split position 13 tentatively determined in step S12 (shown in FIG. 3). ) Is determined (adopted) as the split position 13 of the tread segment 12 (step S18). As a result, in the split position determination method of this embodiment, as in the split position determination method of the previous embodiment, the split position 13 of the tread segment 12 capable of improving uniformity while reducing pitch noise is surely determined. Can be decided.

In step S17, the nth-order phase difference Δ∠F _n is the split position of the previous embodiment in order to reliably determine the split position 13 of the tread segment 12 that can further improve the uniformity while further reducing the pitch noise. It may be determined whether or not the range is the same as that of the determination method. Further, in step S17, whether or not the total number of the unit pulse 24 (shown in FIG. 11) of the first pulse train 21 and the unit pulse 25 (shown in FIG. 5) of the second pulse train 22 is 30 to 100. It may be judged.

Next, a method for designing the tire 1 shown in FIG. 1 (hereinafter, may be simply referred to as a “design method”) will be described. In this design method, the arrangement of the pattern building blocks 4 shown in FIG. 1 and the split position 13 of the tread segment 12 shown in FIG. 3 are determined. In the design method of this embodiment, for example, a known computer (not shown) is used.

FIG. 14 is a flowchart showing an example of a processing procedure of a tire design method. In this embodiment, the same configurations as those in the previous embodiments are designated by the same reference numerals, and the description thereof may be omitted.

In the design method of this embodiment, first, the pattern row 5 included in the tread pattern 3 of the tire 1 shown in FIG. 1 is arranged in the tire circumferential direction of the pattern constituent units 4 constituting the pattern row 5 (pattern row 5). Is tentatively determined (step S21). This step S21 can be carried out, for example, based on the same procedure as the step S2 for tentatively determining the sequence determination method shown in FIG.

Next, in the design method of this embodiment, the split position 13 of the tread segment 12 shown in FIG. 3 in the tire circumferential direction is tentatively determined (step S22). This step S22 can be carried out, for example, based on the same procedure as the step S12 for tentatively determining the split position determination method shown in FIG.

Next, in the design method of this embodiment, the first pulse train 21 (shown in FIG. 4) is acquired from the tentatively determined pattern train 5 (shown in FIG. 1) (step S23). As shown in FIG. 4, in this embodiment, each pattern constituent unit 4 (shown in FIG. 1) of the pattern sequence 5 tentatively determined in step S21 is a unit pulse 24 having the same magnitude B1. ing. Then, the first pulse train 21 can be acquired by arranging these unit pulses 24 in the order of the arrangement of the pattern constituent units 4 with an interval G1. The first pulse train 21 can be obtained based on the same procedure as the above-mentioned sequencing method.

Next, in the design method of this embodiment, the second pulse train 22 (shown in FIG. 5) is acquired from the tentatively determined tread segment row 30 (shown in FIG. 3) (step S24). As shown in FIG. 5, in this embodiment, each tread segment 12 (shown in FIG. 3) tentatively determined in step S22 is a unit pulse 25 having the same size. Then, the second pulse train 22 can be acquired by arranging these unit pulses 25 in the order of the arrangement of the tread segments 12 with an interval G2. The second pulse train 22 can be obtained based on the same procedure as the above-mentioned sequencing method.

Next, in the design method of this embodiment, the phase ∠F _Ak of the 1st to kth order obtained by Fourier transforming the first pulse train 21 shown in FIG. 4 by the following equation (13) is acquired (step S25). ). The following formula (13) is the same as the above formula (1). The details of the phase ∠F _Ak (in FIG. 7, the phase ∠F _An is shown) are as described above.

ここで、
Ｎ：第１パルス列の単位パルスの個数
Ｌ：第１パルス列の全長
ｋ：１～Ｎまでの自然数
Ｘ（ｊ）：第１パルス列の起点からｊ番目の単位パルス位置

here,
N: Number of unit pulses in the first pulse train L: Overall length of the first pulse train k: Natural number from 1 to N X (j): Jth unit pulse position from the starting point of the first pulse train

Next, in the design method of this embodiment, the phase ∠F _Bk of the 1st to kth order obtained by Fourier transforming the second pulse train 22 shown in FIG. 5 by the following equation (14) is acquired (step S26). ). The following formula (14) is the same as the above formula (2). The details of the phase ∠F _Bk (in FIG. 9, the phase ∠F _Bn is shown) are as described above.

ここで、
ｎ：第２パルス列の単位パルスの個数
Ｌ：第２パルス列の全長
ｋ：１～Ｎまでの自然数
Ｘ（ｊ）：第２パルス列の起点からｊ番目の単位パルスの位置

here,
n: Number of unit pulses in the second pulse train L: Overall length of the second pulse train k: Natural number from 1 to N X (j): Position of the jth unit pulse from the starting point of the second pulse train

Next, in the design method of this embodiment, of the 1st to kth order phase difference Δ∠F _k obtained by the following equation (15), the nth order phase difference Δ∠F corresponding to the number of divisions of the tread segment 12 It is determined whether or not _n is −180 to −120 degrees or 120 to 180 degrees (step S27). The following formula (15) is the same as the above formula (3). The details of the 1st to kth order phase difference Δ∠F _k and the nth order phase difference Δ∠F _n are as described above.

When it is determined that the nth-order phase difference Δ∠F _n is within the above range (“Y” in step S27), the phase ∠F _An of the first pulse train 21 (pattern train 5) (shown in FIG. 7). And the phase ∠F _Bn (shown in FIG. 9) of the second pulse train 22 (row 30 of the tread segment) is approaching the opposite phase. In such a case, mutual interference between the noise caused by the pattern row 5 of the tread pattern 3 and the noise caused by the number of divisions of the tread segment 12 can be reduced, and the pitch noise can be further reduced. Therefore, the arrangement of the pattern constituent units 4 (shown in FIG. 1) tentatively determined in the step S21 is determined (adopted) as the arrangement of the pattern constituent units 4 in the pattern row 5 (step S28). Further, the split position 13 (shown in FIG. 3) tentatively determined in step S22 is determined (adopted) as the split position 13 of the tread segment 12 (step S29).

On the other hand, when it is determined that the nth-order phase difference Δ∠F _n is out of the above range (“N” in step S27), the phase ∠F An of the first pulse train 21 (pattern train 5) and the second phase ∠F _An . The phase ∠F _Bn of the pulse train 22 (the row 30 of the tread segment) does not approach the opposite phase. Therefore, it is determined that there is room for improvement in the tentatively determined arrangement of the pattern constituent units 4 (shown in FIG. 1) and the split position 13 of the tread segment 12 (shown in FIG. 3). The step S21 for tentatively determining the arrangement of the pattern constituent unit 4 and the step S22 for tentatively determining the split position 13 of the tread segment 12 are carried out again, and the steps S23 to S27 are carried out again. In steps S21 and S22, the arrangement of the pattern constituent units 4 and the arrangement of the pattern constituent units 4 so that the combination of the arrangement of the pattern constituent units 4 and the split position 13 of the tread segment 12 does not overlap with the previously tentatively determined combination. , It is desirable that the split position 13 is tentatively determined.

As described above, in the design method of this embodiment, of the 1st to kth order phase difference Δ∠F _k , the nth order phase difference Δ∠F _n is −180 to −120 degrees or 120 to 180 degrees. The arrangement of the pattern constituent unit 4 shown in FIG. 1 and the split position 13 shown in FIG. 3 are determined so as to be. Therefore, in the design method, the tire 1 that can surely reduce the pitch noise can be surely designed (the arrangement of the pattern constituent units 4 and the split position 13 of the tread segment 12 are determined).

In step S27, the nth-order phase difference Δ∠F _n is −180 in order to surely determine the arrangement of the pattern constituent units 4 and the split position 13 that can improve the uniformity while further reducing the pitch noise. It is desirable to determine whether it is ~ -150 degrees or 150-180 degrees. More preferably, it is desirable to determine whether or not the temperature is −180 to −160 degrees or 160 to 180 degrees.

Further, in step S27, the interval G1 of each unit pulse 24 of the first pulse train 21 shown in FIG. 4 (in this example, the ratio of the length D1 of all the pattern constituent units 4 to the median value) is 0.8 to It may be determined whether or not it is set to 1.2. This makes it possible to determine the arrangement of the pattern constituent units 4 that can prevent uneven wear of the tread portion 2 while exhibiting the noise reduction effect due to the pitch variation.

Further, in step S27, whether or not the total number of the unit pulse 24 (shown in FIG. 4) of the first pulse train 21 and the unit pulse 25 (shown in FIG. 5) of the second pulse train 22 is 30 to 100. It may be judged. This makes it possible to determine the arrangement of the pattern constituent units 4 and the split position 13 that can prevent uneven wear of the tread portion 2 and an increase in the manufacturing cost of the tread segment 12 while exhibiting the noise reduction effect.

In the design method of this embodiment, the unit pulse 24 (shown in FIG. 4) of the first pulse train 21 all has the same magnitude B1 and the unit pulse 25 (shown in FIG. 5) of the second pulse train 22 is. Both have the same size B2, but are not limited to such an embodiment. In this embodiment, the same configurations as those in the previous embodiments are designated by the same reference numerals, and the description thereof may be omitted.

In step S23 of this embodiment, as shown in FIG. 11, each pattern constituent unit 4 of the pattern train 5 shown in FIG. 1 has a size B1 corresponding to the length D1 in the tire circumferential direction. The first pulse train 21 as the pulse 24 is acquired. The size B1 is defined by the same procedure as in the previous embodiments.

In step S24 of this embodiment, each tread segment 12 of the tread segment row 30 shown in FIG. 3 is a second pulse train having a unit pulse 25 having a size B2 corresponding to the length D4 in the tire circumferential direction. 22 (shown in FIG. 5) is acquired. The size B2 is defined by the same procedure as in the previous embodiments.

In step S25 of this embodiment, the phase ∠F _Ak of the 1st to kth order obtained by Fourier transforming the first pulse train 21 shown in FIG. 11 by the following equation (22) is acquired. The following formula (22) is the same as the above formula (4). The details of the phase ∠F _Ak are as described above.

ここで、
Ｎ：第１パルス列の単位パルスの個数
Ｌ：第１パルス列の全長
ｋ：１～Ｎまでの自然数
Ｘ（ｊ）：第１パルス列の起点からｊ番目の単位パルス位置
Ｐ（ｊ）：第１パルス列の起点からｊ番目の単位パルスの大きさ

here,
N: Number of unit pulses in the first pulse train L: Total length of the first pulse train k: Natural number from 1 to N X (j): Jth unit pulse position from the starting point of the first pulse train P (j): First pulse train The magnitude of the jth unit pulse from the starting point of

In step S26 of this embodiment, the phase ∠F _Bk of the 1st to kth order obtained by Fourier transforming the second pulse train 22 shown in FIG. 5 by the following equation (23) is acquired. The following formula (23) is the same as the above formula (5). The details of the phase ∠F _Bk are as described above.

ここで、
ｎ：第２パルス列の単位パルスの個数
Ｌ：第２パルス列の全長
ｋ：１～Ｎまでの自然数
Ｘ（ｊ）：第２パルス列の起点からｊ番目の単位パルスの位置
Ｐ（ｊ）：第２パルス列の起点からｊ番目の単位パルスの大きさ

here,
n: Number of unit pulses in the second pulse train L: Total length of the second pulse train k: Natural number from 1 to N X (j): Position of the jth unit pulse from the starting point of the second pulse train P (j): Second The magnitude of the jth unit pulse from the starting point of the pulse train

Next, in step S27 of this embodiment, of the 1st to kth-order phase differences Δ∠F _k obtained by the following equation (24), the n-th-order phase difference Δ∠F corresponding to the number of divisions of the tread segment 12 It is determined whether _n is −180 to −120 degrees or 120 to 180 degrees. The following formula (24) is the same as the above formula (6). The details of the 1st to kth order phase difference Δ∠F _k and the nth order phase difference Δ∠F _n are as described above.

When it is determined that the nth-order phase difference Δ∠F _n is within the above range (“Y” in step S27), the arrangement of the pattern constituent units 4 (shown in FIG. 1) tentatively determined in step S21. Is determined (adopted) as the arrangement of the pattern constituent unit 4 of the pattern row 5 (step S28). Further, the split position 13 (shown in FIG. 3) tentatively determined in step S22 is determined (adopted) as the split position 13 of the tread segment 12 (step S29).

Thereby, in the design method of this embodiment, as in the previous embodiment, the arrangement of the pattern constituent units 4 (shown in FIG. 1) and the split position 13 (FIG. 1) which can improve the uniformity while reducing the pitch noise and the split position 13 (FIG. 1). (Shown in 3) can be reliably determined (tire 1 is designed).

In step S27, in order to more reliably determine the arrangement of the pattern constituent units 4 that can improve the uniformity while reducing the pitch noise and the split position 13 of the tread segment 12, the nth-order phase difference Δ∠F _n . However, it may be determined whether or not the range is the same as that of the previous embodiment. Further, in step S27, the size B1 and the interval G1 of each unit pulse 24 of the first pulse train 21 shown in FIG. 11 (in this example, the ratio of the length D1 of all the pattern constituent units 4 to the median value) are determined. It may be determined whether or not it is set to 0.8 to 1.2. Further, in step S27, whether or not the total number of the unit pulse 24 (shown in FIG. 11) of the first pulse train 21 and the unit pulse 25 (shown in FIG. 5) of the second pulse train 22 is 30 to 100. It may be judged.

Although the particularly preferred embodiment of the present invention has been described in detail above, the present invention is not limited to the illustrated embodiment and can be modified into various embodiments.

[Example A]
A block pattern tire having the basic configuration shown in FIG. 1 and having the specifications shown in Tables 1 and 2 was prototyped using the vulcanization dies shown in FIGS. 2 and 3 (Example 1). ~ 4, and Comparative Example 1). In Table 1, the arrangement of the pattern constituent units of the tire A is shown as a representative. The arrangement of the pattern constituent units of the tires B to E in Table 2 was set by changing the phase angle of each pattern constituent unit of the tire A.

The tread portion of each test tire has a tread pattern including a pattern row in which pattern constituent units are arranged, and a row of parting regions divided by parting lines formed corresponding to the split positions of the tread segments. Have. As shown in Table 1, each test tire has a different pattern row, but the row in the parting region is the same.

For each test tire, a first pulse train (shown in FIG. 4 as an example) was obtained from the pattern train. In the first pulse train, each pattern constituent unit is a unit pulse having the same size, and the unit pulses are arranged in the order of the pattern constituent units, and the intervals according to the length of each pattern constituent unit in the tire circumferential direction are set. They are arranged side by side.

Next, for each test tire, a second pulse train (shown in FIG. 5 as an example) was obtained from the row in the parting region. In the second pulse train, each parting region is a unit pulse having the same size, and the unit pulses are set in the order of the arrangement of the parting regions and the intervals according to the length of each parting region in the tire circumferential direction. They are arranged side by side.

Next, for each test tire, the 1st to kth-order phase ∠F _Ak obtained by Fourier transforming the first pulse train with the above equation (1) is obtained, and the second pulse train is Fourier transformed with the above equation (2). The phase ∠F _Bk of the 1st to kth order obtained by the above was obtained. Then, of the 1st to kth order phase differences Δ∠F _k obtained by the above equation (3), the nth order phase difference Δ∠F _n was obtained for each test tire, and their performance was evaluated. .. The common specifications and test methods are as follows.
Tire size: 195 / 65R15
Rim size: 15 x 6.5J
Internal pressure: 230 kPa
Load: 4.20kN
Pattern row (4 rows):
Number of types of pattern composition units: 5
Columns in the parting area (columns in the tread segment):
Total number: 9
Number of types: 1 (The length in the tire circumferential direction is the same)
First pulse train:
Unit pulse interval: 0.8 to 1.2
Total number of unit pulses in the first pulse train and the second pulse train: 69

<Tire uniformity>
The RFV (radial force variation) of each test tire was measured using a uniformity tester in accordance with the "Uniformity test method for automobile tires" of JASO C607. The evaluation speed is 60 km / h. The results are displayed as an exponent with Comparative Example 1 as 100. The smaller the number, the better the uniformity.

<Vibration noise test>
Each test tire was rim-assembled on the rim and mounted on the right front wheel of a 1800cc domestic passenger car under the conditions of the internal pressure and the load. The left front wheel and the rear wheel were equipped with slick tires without a tread pattern. The vibration noise level (evaluating both vibration and noise (including pitch noise) in the vehicle) when the vehicle is driven on a smooth road surface and coasted from 60 km / h to 20 km / h is the driver's sensuality. Was evaluated by the 10-point method. The higher the number, the better the result. The results of the test are shown in Table 2.

As a result of the test, the embodiment in which the nth-order phase difference Δ∠F _n is set within a preferable range improves uniformity while reducing pitch noise (including vibration in the vehicle) as compared with the comparative example. I was able to.

[Example B]
For the tires A to E of Example A, the first pulse train and the second pulse train were acquired (Examples 5 to 8 and Comparative Example 2). Unlike Example A, the first pulse train and the second pulse train are acquired as unit pulses having a size corresponding to the length in the tire circumferential direction (shown in FIG. 11 as an example of the first pulse train). ).

Next, for each test tire, the 1st to kth-order phase ∠F _Ak obtained by Fourier transforming the first pulse train with the above equation (4) is obtained, and the second pulse train is Fourier transformed with the above equation (5). The phase ∠F _Bk of the 1st to kth order obtained by the above was obtained. Then, for each test tire, the phase difference Δ∠F _k of the 1st to kth order obtained by the above equation (6) was acquired, and their performance was evaluated. The common specifications and test methods are the same as in Example A.
The test results are shown in Table 3.

As a result of the test, in the example in which the nth-order phase difference Δ∠F _n was set within a preferable range, the uniformity could be improved while reducing the pitch noise as compared with the comparative example.

[Example C]
A tire having the basic configuration shown in FIG. 1 and having a block pattern was prototyped using the vulcanization dies shown in FIGS. 2 and 3 (Examples 2 and 9 to 11). The tread portion of each test tire has a tread pattern including a pattern row in which pattern constituent units are arranged, and a row of parting regions divided by parting lines formed corresponding to the split positions of the tread segments. Have. It should be noted that each test tire has an arrangement of the pattern constituent units of the tire B in Table 1. Further, the columns of the parting area are all the same as in Example A.

Next, for each test tire, the first pulse train (shown in FIG. 4 as an example) is acquired from the pattern train, and the second pulse train (as an example) is obtained from the row in the parting region, based on the same procedure as in Example A. , Shown in FIG. 5) was acquired. Next, for each test tire, the 1st to kth-order phase ∠F _Ak obtained by Fourier transforming the first pulse train with the above equation (1) is obtained, and the second pulse train is Fourier transformed with the above equation (2). The phase ∠F _Bk of the 1st to kth order obtained by the above was obtained. Then, for each test tire, the phase difference Δ∠F _k of the 1st to kth order obtained by the above equation (3) was acquired, and their performance was evaluated. The test method is the same as that of Example A except for the uneven wear resistance performance.

<Uneven wear resistance>
A wear energy measuring device was used to measure the wear energy of each pattern row. The result is an index with the wear energy of Example 2 as 100, and the larger the value, the smaller the wear energy and the better the uneven wear resistance performance.
The results of the test are shown in Table 4.

As a result of the test, in the embodiment in which the unit pulse interval of the first pulse train is preferable, uniformity and uneven wear resistance can be improved while reducing pitch noise.

1 tire 2 tread part 3 tread pattern 4 pattern constituent unit 5 pattern row 17 parting area 18 parting area row

Claims (11)

A tire with a tread
In the tread part
A tread pattern including a pattern array in which the pattern constituent units are arranged in the tire circumferential direction,
It has a row of parting areas separated by parting lines formed corresponding to the split positions of the plurality of tread segments for forming the tread pattern.
From the pattern sequence, each pattern constituent unit is a unit pulse having the same size, and the unit pulse is arranged in the order of the pattern constituent units and according to the length of each pattern constituent unit in the tire circumferential direction. Obtain the first pulse trains arranged at intervals
From the row of the parting regions, each parting region is a unit pulse having the same magnitude, and the unit pulse is arranged in the order of the parting regions and the length of each parting region in the tire circumferential direction. Obtained a second pulse train arranged at intervals according to
The phase ∠F _Ak of the 1st to kth order obtained by Fourier transforming the first pulse train by the following equation (1) is obtained.
When the phase ∠F _Bk of the 1st to kth order obtained by Fourier transforming the second pulse train by the following equation (2) is obtained,
Of the 1st to kth order phase differences Δ∠F _k obtained by the following equation (3), the nth order phase difference Δ∠F _n is −180 to −120 degrees or 120 to 180 degrees.
tire.

here,
N: Number of unit pulses in the first pulse train n: Number of unit pulses in the second pulse train L: Total length of the first pulse train or total length of the second pulse train k: Natural number from 1 to N X (j): 1st The jth unit pulse position from the starting point of the pulse train, or the jth unit pulse position from the starting point of the second pulse train. A tire with a tread
In the tread part
A tread pattern including a pattern array in which the pattern constituent units are arranged in the tire circumferential direction,
It has a row of parting areas separated by parting lines formed corresponding to the split positions of the plurality of tread segments for forming the tread pattern.
From the pattern sequence, each pattern constituent unit is a unit pulse having a size corresponding to the length in the tire circumferential direction, and the unit pulse is in the order of the arrangement of the pattern constituent units and the tire of each pattern constituent unit. Obtained a first pulse train arranged at intervals according to the length in the circumferential direction.
From the row of the parting regions, each parting region is defined as a unit pulse having a size corresponding to the length in the tire circumferential direction, and the unit pulse is used in the order of the arrangement of the parting regions and each parting. Obtained a second pulse train arranged at intervals according to the length of the region in the tire circumferential direction.
The phase ∠F _Ak of the 1st to kth order obtained by Fourier transforming the first pulse train by the following equation (4) is obtained.
When the phase ∠F _Bk of the 1st to kth order obtained by Fourier transforming the second pulse train by the following equation (5) is obtained,
Of the 1st to kth order phase differences Δ∠F _k obtained by the following equation (6), the nth order phase difference Δ∠F _n is −180 to −120 degrees or 120 to 180 degrees.
tire.

here,
N: Number of unit pulses in the first pulse train n: Number of unit pulses in the second pulse train L: Total length of the first pulse train or total length of the second pulse train k: Natural number from 1 to N X (j): 1st The jth unit pulse position from the starting point of the pulse train, or the jth unit pulse position from the starting point of the second pulse train P (j): The magnitude of the jth unit pulse from the starting point of the first pulse train, or the second The magnitude of the jth unit pulse from the starting point of the pulse train The tire according to claim 1 or 2, wherein the nth-order phase difference Δ∠F _n is −180 to −150 degrees or 150 to 180 degrees. The interval of each unit pulse in the first pulse train is defined by the ratio of the length of the pattern building unit corresponding to that unit pulse to the median of the length of all the pattern building units.
The tire according to any one of claims 1 to 3, wherein the interval between the unit pulses of the first pulse train is 0.8 to 1.2. The tire according to any one of claims 1 to 4, wherein the total number of the unit pulse of the first pulse train and the unit pulse of the second pulse train is 30 to 100. It is a method for determining the arrangement in the tire circumferential direction of the pattern constituent units constituting the pattern sequence with respect to the pattern sequence included in the tread pattern of the tire.
The tread pattern is formed by a plurality of tread segments having predetermined split positions in the tire circumferential direction.
The method is
From the pattern sequence, each pattern constituent unit is a unit pulse having the same size, and the unit pulse is arranged in the order of the pattern constituent units and according to the length of each pattern constituent unit in the tire circumferential direction. Obtain the first pulse trains arranged at intervals
From the row of the tread segments, each tread segment is a unit pulse having the same size, and the unit pulses are spaced in the order of the arrangement of the tread segments and according to the length of each tread segment in the tire circumferential direction. Obtained a second pulse train arranged with a gap in
The phase ∠F _Ak of the 1st to kth order obtained by Fourier transforming the first pulse train by the following equation (7) is obtained.
When the phase ∠F _Bk of the 1st to kth order obtained by Fourier transforming the second pulse train by the following equation (8) is obtained,
Of the 1st to kth order phase difference Δ∠F _k obtained by the following equation (9), the nth order phase difference Δ∠F _n is set to −180 to −120 degrees or 120 to 180 degrees. , Including the step of determining the sequence,
How to determine the arrangement of tire pattern constituent units.

here,
N: Number of unit pulses in the first pulse train n: Number of unit pulses in the second pulse train L: Total length of the first pulse train or total length of the second pulse train k: Natural number from 1 to N X (j): 1st The jth unit pulse position from the starting point of the pulse train, or the jth unit pulse position from the starting point of the second pulse train. It is a method for determining the split position of the tread segment in the tire circumferential direction for a plurality of tread segments for forming a tread pattern of a tire.
The tread pattern includes a pattern sequence in which the arrangement of the pattern constituent units in the tire circumferential direction is predetermined.
The method is
From the pattern sequence, each pattern constituent unit is a unit pulse having the same size, and the unit pulse is arranged in the order of the pattern constituent units and according to the length of each pattern constituent unit in the tire circumferential direction. Obtain the first pulse trains arranged at intervals
From the row of the tread segments, each tread segment is a unit pulse having the same size, and the unit pulses are spaced in the order of the arrangement of the tread segments and according to the length of each tread segment in the tire circumferential direction. Obtained a second pulse train arranged with a gap in
The phase ∠F _Ak of the 1st to kth order obtained by Fourier transforming the first pulse train by the following equation (10) is obtained.
When the phase ∠F _Bk of the 1st to kth order obtained by Fourier transforming the second pulse train by the following equation (11) is obtained,
Of the 1st to kth order phase differences Δ∠F _k obtained by the following equation (12), the nth order phase difference Δ∠F _n is set to −180 to −120 degrees or 120 to 180 degrees. , Including the step of determining the split position,
How to determine the split position of the tread segment.

here,
N: Number of unit pulses in the first pulse train n: Number of unit pulses in the second pulse train L: Total length of the first pulse train or total length of the second pulse train k: Natural number from 1 to N X (j): 1st The jth unit pulse position from the starting point of the pulse train, or the jth unit pulse position from the starting point of the second pulse train. It is a method for designing a tire provided with a tread pattern including a pattern array in which pattern building blocks are arranged in the tire circumferential direction.
The tread pattern is formed by a plurality of tread segments divided in the tire circumferential direction.
The method is
From the pattern sequence, each pattern constituent unit is a unit pulse having the same size, and the unit pulse is arranged in the order of the pattern constituent units and according to the length of each pattern constituent unit in the tire circumferential direction. Obtain the first pulse trains arranged at intervals
From the row of the tread segments, each tread segment is a unit pulse having the same size, and the unit pulses are spaced in the order of the arrangement of the tread segments and according to the length of each tread segment in the tire circumferential direction. Obtained a second pulse train arranged with a gap in
The phase ∠F _Ak of the 1st to kth order obtained by Fourier transforming the first pulse train by the following equation (13) is obtained.
When the phase ∠F _Bk of the 1st to kth order obtained by Fourier transforming the second pulse train by the following equation (14) is obtained,
Of the 1st to kth order phase differences Δ∠F _k obtained by the following equation (15), the nth order phase difference Δ∠F _n is set to −180 to −120 degrees or 120 to 180 degrees. , Including a step of determining the arrangement of the pattern constituent units and the split position of the tread segment.
How to design a tire.

here,
N: Number of unit pulses in the first pulse train n: Number of unit pulses in the second pulse train L: Total length of the first pulse train or total length of the second pulse train k: Natural number from 1 to N X (j): 1st The jth unit pulse position from the starting point of the pulse train, or the jth unit pulse position from the starting point of the second pulse train. It is a method for determining the arrangement in the tire circumferential direction of the pattern constituent units constituting the pattern sequence with respect to the pattern sequence included in the tread pattern of the tire.
The tread pattern is formed by a plurality of tread segments having predetermined split positions in the tire circumferential direction.
The method is
From the pattern sequence, each pattern constituent unit is a unit pulse having a size corresponding to the length in the tire circumferential direction, and the unit pulse is in the order of the arrangement of the pattern constituent units, and the said of each pattern constituent unit. Obtained the first pulse train arranged at intervals according to the length.
From the row of tread segments, each tread segment is a unit pulse having a size corresponding to the length in the tire circumferential direction, and the unit pulse is in the order of the arrangement of the tread segments and the length of each tread segment. Obtain a second pulse train arranged at intervals according to the length.
The phase ∠F _Ak of the 1st to kth order obtained by Fourier transforming the first pulse train by the following equation (16) is obtained.
When the phase ∠F _Bk of the 1st to kth order obtained by Fourier transforming the second pulse train by the following equation (17) is obtained,
Of the 1st to kth order phase difference Δ∠F _k obtained by the following equation (18), the nth order phase difference Δ∠F _n is set to −180 to −120 degrees or 120 to 180 degrees. , Including the step of determining the sequence,
How to determine the arrangement of tire pattern constituent units.

here,
N: Number of unit pulses in the first pulse train n: Number of unit pulses in the second pulse train L: Total length of the first pulse train or total length of the second pulse train k: Natural number from 1 to N X (j): 1st The jth unit pulse position from the starting point of the pulse train, or the jth unit pulse position from the starting point of the second pulse train P (j): The magnitude of the jth unit pulse from the starting point of the first pulse train, or the second The magnitude of the jth unit pulse from the starting point of the pulse train It is a method for determining the split position of the tread segment in the tire circumferential direction for a plurality of tread segments for forming a tread pattern of a tire.
The tread pattern includes a pattern sequence in which the arrangement of the pattern constituent units in the tire circumferential direction is predetermined.
The method is
From the pattern sequence, each pattern constituent unit is a unit pulse having a size corresponding to the length in the tire circumferential direction, and the unit pulse is in the order of the arrangement of the pattern constituent units, and the said of each pattern constituent unit. Obtained the first pulse train arranged at intervals according to the length.
From the row of tread segments, each tread segment is a unit pulse having a size corresponding to the length in the tire circumferential direction, and the unit pulse is in the order of the arrangement of the tread segments and the length of each tread segment. Obtain a second pulse train arranged at intervals according to the length.
The phase ∠F _Ak of the 1st to kth order obtained by Fourier transforming the first pulse train by the following equation (19) is obtained.
When the phase ∠F _Bk of the 1st to kth order obtained by Fourier transforming the second pulse train by the following equation (20) is obtained,
Of the 1st to kth order phase differences Δ∠F _k obtained by the following equation (21), the nth order phase difference Δ∠F _n is set to −180 to −120 degrees or 120 to 180 degrees. , Including the step of determining the split position,
How to determine the split position of the tread segment.

here,
N: Number of unit pulses in the first pulse train n: Number of unit pulses in the second pulse train L: Total length of the first pulse train or total length of the second pulse train k: Natural number from 1 to N X (j): 1st The jth unit pulse position from the starting point of the pulse train, or the jth unit pulse position from the starting point of the second pulse train P (j): The magnitude of the jth unit pulse from the starting point of the first pulse train, or the second The magnitude of the jth unit pulse from the starting point of the pulse train It is a method for designing a tire provided with a tread pattern including a pattern array in which pattern constituent units are arranged in the tire circumferential direction.
The tread pattern is formed by a plurality of tread segments divided in the tire circumferential direction.
The method is
From the pattern sequence, each pattern constituent unit is a unit pulse having a size corresponding to the length in the tire circumferential direction, and the unit pulse is in the order of the arrangement of the pattern constituent units, and the said of each pattern constituent unit. Obtained the first pulse train arranged at intervals according to the length.
From the row of tread segments, each tread segment is a unit pulse having a size corresponding to the length in the tire circumferential direction, and the unit pulse is in the order of the arrangement of the tread segments and the length of each tread segment. Obtain a second pulse train arranged at intervals according to the length.
The phase ∠F _Ak of the 1st to kth order obtained by Fourier transforming the first pulse train by the following equation (22) is obtained.
When the phase ∠F _Bk of the 1st to kth order obtained by Fourier transforming the second pulse train by the following equation (23) is obtained,
Of the 1st to kth order phase differences Δ∠F _k obtained by the following equation (24), the nth order phase difference Δ∠F _n is set to −180 to −120 degrees or 120 to 180 degrees. , Including a step of determining the arrangement of the pattern constituent units and the split position of the tread segment.
How to design a tire.

here,
N: Number of unit pulses in the first pulse train n: Number of unit pulses in the second pulse train L: Total length of the first pulse train or total length of the second pulse train k: Natural number from 1 to N X (j): 1st The jth unit pulse position from the starting point of the pulse train, or the jth unit pulse position from the starting point of the second pulse train P (j): The magnitude of the jth unit pulse from the starting point of the first pulse train, or the second The magnitude of the jth unit pulse from the starting point of the pulse train

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