JP2010208090A - Method for producing ply member, strip-shaped ply, and pneumatic tire - Google Patents

Abstract

A method of manufacturing a ply member capable of making the thickness and modulus of the ply member uniform without impairing productivity, a strip-like ply that can be used in the method, and a ply member comprising the strip-like ply A pneumatic tire provided with
A cutting step of obtaining a strip-shaped ply by cutting a long strip-shaped ply formed by covering a plurality of cords arranged in parallel with rubber with a predetermined length, and a width of the strip-shaped ply 11 In a method for manufacturing a ply member, the strip-like ply 11 is positioned on the center side in the width direction W, and is thinner than the main body portion 11A. And a joint portion 11B having a cord structure having a lower modulus than the cord structure of the main body portion 11A. In the joining step, one joint portion 11B of the strip-like plies 11 adjacent to each other is Are joined to the joint 11B.
[Selection] Figure 3

Description

  The present invention relates to a method for manufacturing a ply member that is a constituent member of a pneumatic tire, a strip-like ply that can be used in the method, and a pneumatic tire that includes a ply member made of the strip-like ply.

  Normally, the constituent members of a pneumatic tire include various ply members formed by rubber-coating a plurality of cords arranged in parallel. Typical examples of the ply member include a carcass ply constituting a carcass layer serving as a skeleton of a tire and a belt ply constituting a belt layer for reinforcing the carcass layer with an effect.

  The ply member is used for tire molding by pulling out the necessary length from a long belt-shaped ply wound up in a roll shape, cutting it at a length corresponding to the tire circumferential length, and attaching it to a molding drum. Is done. However, since the required width and cord angle of the ply member differ depending on the tire specification and size, it is necessary to prepare various types of belt-like plies and store their rolls. Was a problem. Therefore, as an alternative, a method has been proposed in which a large number of strip-like plies are sequentially joined to form a strip, which is used for tire molding.

  Patent Document 1 below describes a method of forming a carcass ply by sequentially sticking narrow strip-like plies on a forming drum. In this method, a long and narrow belt-like ply is cut into a strip-like ply, and the strip-like ply is sequentially attached in a posture in which both side edges are parallel to the axis of the forming drum. Then, as shown in FIG. 9, the strip-like plies 41 adjacent to each other are forcibly drawn and their end faces are butt-joined. Thereby, the carcass ply according to the specification and size of the tire can be appropriately formed without preparing various types of belt-like plies.

  By the way, in the joint portion formed by butt joining as described above, it is necessary to increase the joining strength by applying a zipper 45 as shown in FIG. 9 in order to prevent the trouble that the end surfaces are separated from each other at the time of vulcanization molding of the tire. There was a problem that man-hours increased. In particular, strip plies narrowed by a small calender device have been used recently, and a large number of joint points are formed. Will be disturbed.

  On the other hand, as shown in FIG. 10, a method is conceivable in which the ends of the strip-like plies 41 adjacent to each other are overlapped and overlapped. However, in this case, since the thickness and modulus of the ply member are locally increased at the joint portion, the variation in rigidity in the tire circumferential direction increases, and the higher order component of the tire uniformity is likely to appear. When is a carcass ply, various problems such as irregularities are formed on the outer surface of the sidewall portion.

  Patent Document 2 below describes a method of forming a belt ply by sequentially sticking narrow strip-like plies on a conveyor. In this method, a long and narrow strip-shaped ply is cut into a strip-like ply, and the strip-like ply is placed in a posture in which both side edges are inclined at a predetermined angle with respect to the transport direction of the transport conveyor. In the same manner as described above, the end faces adjacent to each other are joined together. Thereby, the belt ply according to the specification and size of the tire can be appropriately formed without preparing various types of belt-like plies.

  However, even in the case of such a belt ply, when the end faces of the strip-like plies are butt-joined to each other, the number of zippers is excessively increased and the productivity is hindered. In addition, there is a problem that the end number of the belt ply is easily disturbed during vulcanization molding, and the plunger energy varies greatly. In addition, when the length of the belt ply corresponding to the tire circumferential length is not an integral multiple of the width dimension of the strip-like ply, strip-like plies having different widths are separately required, which is inefficient. On the other hand, when the ends are overlapped and joined, the thickness and modulus become uneven on the circumference, so that the rigidity fluctuation in the tire circumferential direction increases, and higher-order components of the tire uniformity tend to appear. There arises a problem that the circumferential length of the belt reinforcing layer becomes longer than necessary and tension cannot be obtained appropriately.

  In Patent Document 3 below, in a strip-like ply used for molding a carcass ply or a belt ply, an ear rubber portion is formed by slightly projecting rubber from both end edges, and the strip-like ply arranged in the width direction is used. A method is described in which one ear rubber part is overlapped and joined to the other ear rubber part or the ply body. However, when the ear rubber portions are overlapped with each other, if an attempt is made to sufficiently secure the overlap margin, the cord interval is locally expanded at the joint portion, and the modulus tends to be uneven on the circumference. Further, when the ear rubber part is stacked on the ply body, the thickness is not uniform on the circumference.

  In Patent Document 4 below, a belt-like ply with a half-width range having a large-diameter cord and a half-width range having a thin-diameter cord that is thinner than the large-diameter range is formed in the width direction. A method is described in which the belts are sequentially arranged in the direction, and the small diameter range of one belt-like ply is overlapped with the large diameter range of the other belt-like ply. However, this method is a technique of forming a belt reinforcing layer by winding a long belt-like ply in a spiral, and a joint portion is formed in a spiral along the tire circumferential direction. Therefore, there is no disclosure or suggestion of a solution for solving the above-described problems when a large number of strip-like plies are joined.

JP-A-4-226742 JP 2000-280373 A JP 2001-322403 A JP-A-3-204306

  The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a method for manufacturing a ply member that can achieve uniform thickness and modulus of the ply member without impeding productivity, and the method used for the method. An object of the present invention is to provide a pneumatic tire including a strip-shaped ply to be obtained and a ply member made of the strip-shaped ply.

  The above object can be achieved by the present invention as described below. That is, the manufacturing method of the ply member according to the present invention includes a cutting step of cutting a long strip-shaped ply formed by covering a plurality of cords arranged in parallel with rubber to a predetermined length to obtain a strip-shaped ply. And a joining step of sequentially joining the strip-like plies in the width direction, and sequentially joining the strip-like plies, the strip-like ply is located on the center side in the width direction, and the body portion A thin-walled joint portion having a cord structure having a lower modulus than the cord structure of the main body portion, and in the joining step, the one joint portion of the strip-like plies adjacent to each other Are overlapped and joined to the other joining portion.

  According to the present invention, the strip-like plies adjacent to each other are joined to each other by overlapping the joining portions having a cord structure having a lower thickness and a lower modulus than the main body portion. There is no need to hang up and the productivity of the ply member is not hindered. In addition, the thickness and modulus of the ply member can be made uniform on the circumference by suppressing the thickness and modulus from locally increasing at the joint. For this reason, while suppressing the fluctuation | variation of the rigidity of a tire peripheral direction, the uniformity of a tire can be ensured and appearance of a high-order component can be prevented.

  In the above, it is preferable that the cord embedded in the joint portion has a smaller diameter than the cord embedded in the main body portion. As a result, the cord structure of the joint portion can be reduced in modulus more easily and reliably than the cord structure of the main body portion. Moreover, since it becomes easy to make a junction part thin, the thickness of a ply member can be equalized appropriately.

  As a preferred embodiment of the method for producing a ply member according to the present invention, in the joining step, the strip-like plies are sequentially joined in the width direction so that the extending direction of the cord is substantially perpendicular to the tire circumferential direction. And a ply member that forms a carcass layer of a tire. When the ply member manufactured according to the present invention is a ply member constituting a carcass layer, that is, a carcass ply, in addition to the effect of making the thickness and modulus uniform as described above, there are irregularities on the outer surface of the sidewall portion. The effect that it can suppress that it is formed is show | played and it is very useful.

  As a preferred embodiment of the method for producing a ply member according to the present invention, in the joining step, the strip-like plies are arranged in the width direction so that the extending direction of the cord is inclined at a predetermined angle with respect to the tire circumferential direction. One that sequentially joins and manufactures a ply member that constitutes a belt layer of a tire is mentioned. When the ply member manufactured according to the present invention is a ply member constituting the belt layer, that is, a belt ply, in addition to the effect of uniforming the thickness and modulus as described above, the peripheral length of the belt reinforcing layer is more than necessary. It is very useful because the effect that the tension can be appropriately obtained without being long is obtained.

  Further, the strip-like ply of the present invention is a strip-like ply formed by rubber-coating a plurality of cords arranged in parallel, and has a main body located on the center side in the width direction, and thinner than the main body. And a joint portion having a cord structure having a lower modulus than that of the cord structure of the main body portion. Such a strip-like ply can be used in the above-described method for manufacturing a ply member. By overlapping and joining the joint portions, productivity of the ply member is not hindered, and in addition, the thickness of the ply member can be reduced. It is possible to make the modulus uniform.

  In the above, it is preferable that the cord embedded in the joint portion has a smaller diameter than the cord embedded in the main body portion. As a result, the cord structure of the joint portion can be reduced in modulus more easily and reliably than the cord structure of the main body portion. Moreover, since it becomes easy to make a junction part thin, the thickness of a ply member can be equalized appropriately.

  In the above, it is preferable that the joint portion is gradually reduced in thickness toward the outer side in the width direction. Thereby, it becomes easy to overlap and join the joints, and the thickness of the ply member at the joint can be made uniform.

  Further, the pneumatic tire of the present invention is a pneumatic tire provided with a ply member arranged annularly along the tire circumferential direction. The ply member has a plurality of the above-mentioned strip-shaped plies arranged in the width direction, One of the strip-like plies adjacent to each other is overlapped and joined to the other joint.

  In this pneumatic tire, the thickness and modulus of the ply member are uniformed on the circumference, so that fluctuations in rigidity in the tire circumferential direction are suppressed, and uniformity is ensured to prevent the appearance of higher-order components. Can do. When this ply member is a carcass ply, it is possible to suppress the formation of irregularities on the outer surface of the sidewall portion, and when it is a belt ply, the circumference of the belt reinforcing layer becomes longer than necessary. The tension can be obtained properly without any problems.

Explanatory drawing which shows roughly the apparatus for manufacturing a carcass ply Schematic configuration diagram of belt ply forming device Cross section of strip ply The figure which shows the joint location of the strip-shaped ply of FIG. Tire meridian cross-sectional view schematically showing an example of a pneumatic tire according to the present invention Explanatory drawing which shows roughly the apparatus for manufacturing a belt ply Cross section of strip ply The figure which shows the joint location of the strip-shaped ply of FIG. The figure which shows the joint location of the strip ply in the prior art The figure which shows the joint location of the strip ply in the prior art

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. 1st Embodiment demonstrates the example whose ply member is the carcass ply which comprises the carcass layer of a tire. In the second embodiment, an example in which the ply member is a belt ply constituting a belt layer of a tire will be described. However, the present invention can be applied to ply members other than the carcass ply and the belt ply.

[First Embodiment]
FIG. 1 is an explanatory view schematically showing an apparatus for manufacturing a carcass ply. As will be described later, the carcass ply 14 is manufactured by arranging a number of strip-like plies 11 in the width direction W on the forming drum 12 and sequentially joining them. The belt-like ply 10 is formed by rubber-coating a plurality of cords arranged in parallel, and the extending direction of the cords is uniformly aligned in the longitudinal direction N. The strip-like ply 11 is obtained by cutting the belt-like ply 10 with a cutter 13 at a predetermined length L1.

  The belt-like ply 10 can be formed using, for example, an apparatus as shown in FIG. The extruder 30 includes a cylinder 31 containing a screw and a hopper 32 for putting a rubber material into the cylinder 31. The rubber material thrown into the cylinder 31 is conveyed to the tip of the cylinder 31 by a rotating screw. Cords 36 are supplied from a large number of bobbins 35 to the extruder 30, and a plurality of cords 36 arranged in parallel by a positioning member 33 are covered with a rubber material fed from a cylinder 31, and predetermined through a die 34. Extruded with a cross-sectional shape of

  In addition to the method using the extruder 30 as shown in FIG. 2, the belt-like ply 10 is made of a sheet-like rubber material formed by feeding a plurality of cords arranged in parallel between a pair of calender rolls. It can also be molded by a method of covering, or a method of sandwiching a plurality of cords arranged in parallel with rubber sheets overlapping one above the other. In the apparatus of FIG. 1, the belt-like ply 10 immediately after molding may be supplied, but the belt-like ply 10 thus formed is temporarily wound into a roll and stored, and is unwound from the roll and supplied when necessary. Also good.

  The length L1 of the strip-like ply 11 is set to be equal to the width CW of the carcass ply 14 required for tire molding, and can be appropriately changed according to the specification and size of the tire to be manufactured. As shown in FIG. 3, the strip-shaped ply 11 includes a main body portion 11A located on the center side in the width direction W, and joint portions 11B located on both sides of the main body portion 11A, and the main body portion 11A and the joint portion 11B. The cords 17A and 17B are embedded in each of these. The joint portion 11B is thinner than the main body portion 11A and has a cord structure having a lower modulus than that of the main body portion 11A. In the present embodiment, the joint portion 11B is formed in a trapezoidal cross section, and the thickness is gradually reduced toward the outside in the width direction W.

  In the present embodiment, the cord 17B embedded in the joint portion 11B has a smaller diameter than the cord 17A embedded in the main body portion 11A, whereby the cord structure of the joint portion 11B has a lower modulus than the cord structure of the main body portion 11A. It has become. In order to obtain such a strip-like ply 11, when forming the belt-like ply 10 by the apparatus of FIG. 2, the cord 36 supplied to the center side in the width direction W is used as the large-diameter cord 17A, and the cord supplied to both sides thereof. 36 may be the small-diameter cord 17B, and the number of each can be set as appropriate. Although FIG. 3 shows an example in which six cords 17A are embedded in the main body portion 11A and four cords 17B are embedded in each joint portion 11B, the present invention is not limited to this.

  The procedure for manufacturing the carcass ply 14 is as follows. First, the long belt-like ply 10 is cut with a cutter 13 at a length L1 to obtain a strip-like ply 11 (corresponding to the cutting step). Next, the strip-like ply 11 is conveyed onto the forming drum 12 and is aligned in the width direction W and sequentially joined (corresponding to the joining step). The strip-like plies 11 are arranged so that the extending direction of the cords 17A and 17B is substantially orthogonal to the tire circumferential direction. The tire circumferential direction is the same as the circumferential direction of the forming drum 12. While the molding drum 12 is rotated around the shaft 12 a, a large number of strip-like plies 11 are joined one after another to form a cylindrical carcass ply 14 on the outer periphery of the molding drum 12.

  When joining the strip-like ply 11, as shown in FIG. 4, one joining portion 11B of the strip-like plies 11 adjacent to each other is overlapped and joined to the other joining portion 11B. By overlapping the joint portion 11B having a cord structure with a low modulus, it is possible to suppress the thickness and the modulus from being locally increased at the joint portion, and to make the thickness and the modulus of the carcass ply 14 uniform on the circumference. For this reason, while suppressing the fluctuation | variation of the rigidity of a tire peripheral direction, the uniformity of a tire can be ensured and appearance of a high-order component can be prevented. Moreover, in the tire provided with the carcass ply 14, it can suppress that an unevenness | corrugation is formed in the outer surface of a sidewall part.

  If necessary, the joint location may be pressed in the thickness direction with a roller or the like to increase the bonding strength. Even in such a case, there is no need to hang a zipper at the joint as in the case of the conventional butt joint, so that the productivity of the carcass ply 14 is not hindered.

  In the present embodiment, since the joint portion 11B gradually decreases in thickness toward the outside in the width direction W, the joint portions 11B are easily overlapped and joined as shown in FIG. 4, and the thickness of the carcass ply 14 at the joint portion is reduced. Uniformity can be achieved. In order to obtain the strip-like ply 11 having such a shape, the belt-like ply 10 may be formed using a die 34 having a shape corresponding to this, that is, a die 34 whose thickness is gradually reduced toward the outside in the width direction W.

  After the carcass ply 14 is formed, the other tire constituent members are sequentially supplied onto the forming drum 12, and a predetermined operation is performed to form a green tire. In the present embodiment, an example is shown in which the strip-like ply 11 is joined on the molding drum 12 and thereby the carcass ply 14 is shaped into a cylindrical shape. For example, the strip-like ply is formed on a joining base made of a drum or a conveyor. 11 may be joined to form a sheet-like carcass ply 14 having a length corresponding to the tire circumferential length, and the tire-shaped carcass ply 14 may be attached to a forming drum in a cylindrical shape for use in tire formation.

  An example of the cord diameter of the cord 17A is 0.5 to 0.9 mm. In this case, the cord diameter of the cord 17B is, for example, 0.3 to 0.5 mm. The joint portion 11B includes at least one cord, but it is preferable that each of the joint portions 11B includes three or more cords in order to ensure the overlapping margin of the end portions. Examples of the material of the cords 17A and 17B used for the carcass ply 14 include organic fiber cords such as polyester, rayon, nylon, and aramid, or metallic cords such as steel, and are usually twisted.

  The cord structure of the joint portion 11B has a lower modulus than the cord structure of the main body portion 11A, but the ratio of the tensile modulus per unit width is preferably 0.4 to 0.6, whereby the carcass ply 14 Can be made uniform on the circumference. This tensile modulus is a value calculated from a tensile stress at 2% elongation by performing a tensile test according to JISL 1017.

  In the present embodiment, the cord structure of the joint portion 11B is made to have a lower modulus than the cord structure of the main body portion 11A due to the difference in the cord diameters of the cords 17A and 17B included in the strip-like ply 11. Not limited. That is, as described later, instead of or in addition to the difference in the cord diameter, the material of the cords 17A and 17B, the number of ends (the number of cords per unit width), and the twist pitch are made different from each other, whereby the cord of the joint 11B The structure may have a lower modulus than the code structure of the main body 11A.

  An example of a pneumatic tire provided with the carcass ply 14 described above is shown in FIG. The pneumatic tire T includes a pair of bead portions 1, a sidewall portion 2 that extends from the bead portion 1 to the outside in the tire radial direction, and a tread portion 3 that continues to each outer end of the sidewall portion 2. The bead portion 1 is provided with an annular bead core 1 a and a bead filler 1 b made of hard rubber, and the outside thereof is reinforced by side plies 8.

  The carcass layer 4 is composed of one or more plies, and is composed of one carcass ply 14 in the illustrated example. The carcass ply 14 is arranged so as to be bridged between the bead portions 1 and includes a cord that extends substantially orthogonal to the tire circumferential direction. The carcass ply 14 is formed by joining a large number of strip-like plies 11 as described above, and has a uniform thickness and modulus on the circumference. Therefore, this pneumatic tire T is one in which the rigidity variation in the tire circumferential direction is suppressed and the uniformity is good, and the unevenness on the outer surface of the sidewall portion 2 is suppressed.

  On the outer periphery of the tread portion 3 of the carcass layer 4, a belt layer 5 having two stacked belt plies 15 is disposed, and the carcass layer 4 is reinforced by the effect. Each belt ply 15 includes a cord that extends at an angle of, for example, about 25 ° with respect to the tire circumferential direction, and the cords are arranged so as to cross each other in opposite directions between the plies. A belt reinforcing layer 6 and a tread rubber layer 7 are disposed on the outer peripheral side of the belt layer 5. The following second embodiment relates to the belt ply 15.

[Second Embodiment]
Since the second embodiment is basically the same configuration and action as the first embodiment except that the ply member formed by joining the strip-like plies is the belt ply 15 constituting the belt layer 5, The differences will be mainly described with the common points omitted. In addition, the same code | symbol is attached | subjected to the member and site | part same as the member and site | part demonstrated by 1st Embodiment, and the overlapping description is abbreviate | omitted.

  FIG. 6 is an explanatory view schematically showing an apparatus for manufacturing the belt ply 15. The strip-like ply 21 is obtained by cutting the belt-like ply 20 at a predetermined length L2 with the cutter 23, and the cords are arranged in the width direction so that the cord is inclined at a predetermined angle with respect to the tire circumferential direction. The length L2 of the strip-like ply 21 is set so that the width BW of the belt ply 15 required for tire molding can be obtained when the strip-like plies 21 are arranged in the width direction. It can be appropriately changed according to the size.

  As shown in FIG. 7, the strip-like ply 21 includes a main body portion 21 </ b> A and a joint portion 21 </ b> B, and cords 27 </ b> A and 27 </ b> B are embedded therein. The cord 27B embedded in the joint portion 21B has a smaller diameter than the cord 27A embedded in the main body portion 21A, whereby the cord structure of the joint portion 21B has a lower modulus than the cord structure of the main body portion 21A. The joint portion 21B is formed in a triangular cross section, and the thickness is gradually reduced toward the outer side in the width direction. Although FIG. 7 shows an example in which six cords 27A are embedded in the main body portion 21A and one cord 27B is embedded in each joint portion 21B, the present invention is not limited to this.

  The procedure for manufacturing the belt ply 15 is as follows. First, the long belt-like ply 20 is cut with a cutter 23 at a length L2 to obtain a strip-like ply 21 (corresponding to the cutting step). At this time, cutting is performed so that the cut surface is inclined with respect to the longitudinal direction N. Next, the strip-like ply 21 is transported onto the forming drum 22 and aligned in the width direction and sequentially joined (corresponding to the joining step). The strip-like plies 21 are arranged so that the extending directions of the cords 27A and 27B are inclined at a predetermined angle with respect to the tire circumferential direction. The belt ply 15 is formed in a cylindrical shape on the outer periphery of the forming drum 22 by joining a large number of strip-shaped plies 31 one after another while rotating the forming drum 22 around the shaft 22a.

  When joining the strip-like ply 21, as shown in FIG. 8, one joining portion 21B of the strip-like plies 21 adjacent to each other is overlapped and joined to the other joining portion 21B. As a result, the thickness and modulus of the belt ply 15 can be made uniform on the circumference, the change in rigidity in the tire circumferential direction can be suppressed, and the uniformity of the tire can be secured to prevent the appearance of higher order components. Moreover, it is possible to prevent the belt reinforcing layer 6 from becoming unnecessarily long and to obtain a proper tension.

  After the belt ply 15 is molded, other tire constituent members constituting the belt reinforcing layer 6 and the tread rubber layer 7 are attached to produce a cylindrical molded body. Then, the cylindrical molded body is conveyed to another molding drum provided with the carcass ply 14 and the like, and a predetermined operation is performed to form a green tire. In this embodiment, the strip-like ply 21 is joined on the molding drum 22 to thereby form the belt ply 15 into a cylindrical shape. However, the strip-like ply 21 is placed on a separately installed joining base. It is also possible to form a sheet-like belt ply 15 having a length corresponding to the tire circumferential length, and affix it to a forming drum to form a cylindrical shape.

  An example of the cord diameter of the cord 27A is 0.6 to 1.5 mm. In this case, the cord diameter of the cord 27B is, for example, 0.5 to 0.9 mm. As a material of the cords 27A and 27B used for the belt ply 15, a metallic cord such as steel or an organic fiber cord such as polyester, rayon, nylon, and aramid is used, and usually twisted.

  The cord structure of the joint portion 21B has a lower modulus than the cord structure of the main body portion 21A, but the ratio of the tensile modulus per unit width is preferably 0.4 to 0.6. Can be made uniform on the circumference. The tensile modulus is a value calculated from a tensile stress at 0.5% elongation after a tensile test according to JISG 3510.

[Other Embodiments]
(1) The strip-like ply is such that the cord structure of the joint portion has a lower modulus than the cord structure of the main body portion, but this is not limited to one depending on the difference in the cord diameter, and other elements such as cords It may be based on the material, number of ends, twist pitch, and the like. When depending on the material of the cord, a cord having a lower modulus than that of the cord of the main body may be applied to the cord of the joint portion. In addition, when relying on the number of ends, the number of ends of the joint may be made smaller than the number of ends of the main body. When relying on the twist pitch, the twist pitch of the cord of the joint is determined by the cord of the main body. It may be larger than the twist pitch.

  (2) The shape of the strip-like ply is not particularly limited as long as the joint portion is thinner than the main body portion. Therefore, the cross-sectional shape of the joint may be, for example, a rectangular shape in addition to the trapezoidal shape or the triangular shape described above.

  (3) In the first and second embodiments described above, the example in which the ply member formed by joining a large number of strip-like plies is a carcass ply or a belt ply is shown. For example, the present invention can be applied to the side ply 8 shown in FIG.

DESCRIPTION OF SYMBOLS 10 Belt-like ply 11 Strip-like ply 11A Main part 11B Joining part 12 Molding drum 14 Carcass ply 15 Belt ply 17A Cord 17B Cord 20 Strip-like ply 21 Strip-like ply 21A Body part 21B Joining part 22 Molding drum 27A Cord 27B Cord

Claims (8)

A cutting step of obtaining a strip-shaped ply by cutting a long strip-shaped ply formed by rubber-coating a plurality of cords arranged in parallel with a predetermined length, and sequentially arranging the strip-shaped plies in the width direction In a manufacturing method of a ply member comprising a joining step for joining,
The strip-like ply is located on the center side in the width direction, and the joint portion is located on both sides with a thinner wall than the body portion, and has a cord structure with a lower modulus than the cord structure of the body portion, With
In the joining step, one joining portion of the strip-like plies adjacent to each other is overlapped and joined to the other joining portion.   The method for manufacturing a ply member according to claim 1, wherein the cord embedded in the joint portion has a smaller diameter than the cord embedded in the main body portion.   The ply member constituting the carcass layer of the tire is manufactured by sequentially joining the strip-like plies in the width direction so that the extending direction of the cord is substantially orthogonal to the tire circumferential direction in the joining step. 3. A method for producing a ply member according to 1 or 2.   A ply member that forms a belt layer of the tire by sequentially joining the strip plies in the width direction so that the extending direction of the cord is inclined at a predetermined angle with respect to the tire circumferential direction in the joining step; The manufacturing method of the ply member of Claim 1 or 2 to manufacture.   In a strip-like ply formed by rubber-coating a plurality of cords arranged in parallel, a main body portion located on the center side in the width direction and positioned on both sides with a thinner wall than the main body portion, A strip-like ply comprising: a joint portion having a cord structure having a lower modulus than the cord structure.   The strip-like ply according to claim 5, wherein the cord embedded in the joining portion has a smaller diameter than the cord embedded in the main body portion.   The strip-like ply according to claim 5 or 6, wherein the joint portion gradually decreases in thickness toward the outer side in the width direction.   A pneumatic tire including a ply member arranged annularly along a tire circumferential direction, wherein the ply member includes a plurality of strip-like plies according to any one of claims 5 to 7 arranged in the width direction, A pneumatic tire characterized in that one of the joints of the strip-like plies adjacent to each other is joined to the other joint.

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