JP2004169889A - Pinion shaft supporting bearing device, and pinion shaft supporting device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To achieve compactness, light weight, and low torque of a pinion shaft 5 in a pinion shaft supporting bearing device 1 for supporting a trunk part 5a of the pinion shaft 5 having a pinion gear 5b at one end. <P>SOLUTION: A plurality of lines of outward angular ball bearings 6 are used for supporting the pinion shaft 5, inner space of the bearing 6 is sealed with seals 20 and 30 installed at both axial ends, and grease is enclosed in the sealed inner space of the bearing. In this case, oil used for a subject device of the pinion shaft 5 is not introduced into the bearing 6, thereby nonconformity generated in conventional examples in which oil is introduced into the bearing 6 is eliminated. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a pinion shaft support bearing device and a pinion shaft support device.
[0002]
[Prior art]
BACKGROUND ART Conventionally, as a pinion shaft supporting bearing device for rotatably supporting a pinion shaft incorporated in a transfer or a differential provided in an automobile, a device using two single-row tapered roller bearings (see Patent Document 1), There is one in which a single-row tapered roller bearing and a single-row angular ball bearing are integrated (see Patent Document 2).
[0003]
In any of the above-described bearing devices for supporting a pinion shaft, the pinion gear side is in an open state in which a seal is not mounted, and lubrication is performed using oil stored in a transfer or a differential. .
[0004]
[Patent Document 1]
JP-A-10-220468 [Patent Document 2]
JP-A-53-74653.
[Problems to be solved by the invention]
In recent years, the transfer and differential have been required to reduce the torque of the pinion shaft.
[0006]
However, in any of the above-described pinion shaft supporting bearing devices, there is a limit in torque reduction due to the use of tapered roller bearings. In addition, in the case of the pinion shaft supporting bearing device used for the transfer, the oil in the case reaches the pinion shaft supporting bearing device due to the arrangement of the center axis of the pinion shaft above the center position of the transfer case. It is pointed out that it is difficult. For this reason, the case shape of the transfer must be devised so that the oil can be efficiently introduced into the bearing, and the case must be enlarged. On the other hand, in the case of the bearing device for supporting a pinion shaft used for the differential, the oil is excessively introduced due to the arrangement of the center axis of the pinion shaft below the center position of the transfer case. It is pointed out that this is disadvantageous in reducing the torque, for example, because foreign matters in the oil bite between the tapered rollers and the raceway surface.
[0007]
[Means for Solving the Problems]
The bearing device for supporting a pinion shaft according to the present invention is a bearing device for supporting a body portion of a pinion shaft having a pinion gear at one end, and is a double-row outward-facing angular ball bearing, and is mounted at both axial ends thereof. Grease is sealed in the bearing interior space sealed with a seal.
[0008]
In this case, the double-row outward-facing angular contact ball bearing has a smaller rolling resistance than the tapered roller bearing, which is advantageous in lowering the torque. Moreover, since the double row outward-facing angular contact ball bearing is sealed with a seal and lubricated with grease, the oil inside the target device of the pinion shaft is prevented from being introduced into the bearing. Malfunctions associated with the oils mentioned are eliminated.
[0009]
The double row outward-facing angular contact ball bearing has a single outer ring having two rows of raceways in the axial direction and having counter bores at both ends in the axial direction, and is paired with one raceway of the outer ring. A first inner race having a single raceway surface and having a counterbore at an axially inner end; a single raceway surface paired with the other raceway surface of the outer race and having a counterbore at an axially inner end; And a plurality of balls interposed between the two rows of raceways of the outer race and the raceways of the two inner races. The contact angle of the ball is set to 30 degrees or more and 45 degrees or less, the radius of curvature of each raceway surface of the outer ring is set to 51.0% or more and 52% or less of the diameter of the ball, and each of the inner rings is set. Is set to be 50.2% or more and 51.2% or less of the diameter of the ball.
[0010]
In this case, the contact angle and the radius of curvature of the raceway surface of the double row outward-facing angular ball bearing are specified so as to be different from those of a general standard product, whereby load resistance and durability can be improved.
[0011]
Each of the seals has an outer peripheral portion attached to the two counter bores of the outer ring, and has a shape capable of being brought into contact with each shoulder of the two inner rings on the inner periphery and opening outward of the bearing. The seal disposed on the pinion gear side is such that the lip is forcibly pressed against the inner ring shoulder by a spring ring, and the seal disposed on the anti-pinion gear side includes: It is possible to provide a ventilation section for communicating the inside and outside of the bearing.
[0012]
In this case, since the seal is a type particularly excellent in preventing foreign matter from entering the bearing from the outside to the inside, it is advantageous in stabilizing the properties of grease sealed in the bearing. Further, when the bearing is cooled from a high temperature state to a low temperature state, the pressure inside the bearing becomes lower than the external pressure. In this case, the ventilation inside and outside the bearing by the ventilation part provided in the seal on the anti-pinion gear side. Since the pressure difference between the inside and outside of the bearing can be eliminated, the phenomenon that the seal lip on the anti-pinion gear side is strongly pressed against the shoulder portion of the inner ring (so-called sticking phenomenon) can be prevented.
[0013]
The pinion shaft support device of the present invention includes a pinion shaft having a pinion gear at one end and a screw shaft portion at the other end, a double-row outward-facing angular ball bearing externally mounted on a body of the pinion shaft, and a screw of the pinion shaft. A nut that is screwed and mounted on a shaft portion to integrate the double-row outward angular ball bearing with the pinion shaft, and the double-row outward angular ball bearing is mounted at both axial ends thereof. Grease is sealed in the bearing interior space sealed with a seal.
[0014]
In this case, since the double-row outward-facing angular ball bearing corresponds to the above-described pinion shaft supporting bearing device, the same operation and effect as described above can be obtained. Moreover, since the pinion shaft and the double-row outward-facing angular ball bearing as a bearing device for supporting the pinion shaft are unitized, the time and effort required for assembling the pinion shaft with respect to the object to be used is reduced, and the assemblability is improved.
[0015]
DETAILED DESCRIPTION OF THE INVENTION
One embodiment of the present invention will be described with reference to FIGS. The illustrated pinion shaft support device 1 is incorporated into a transfer or differential case 2 and includes a pinion shaft 5, a double-row outward angular ball bearing 6, a coupling sleeve 7, and a nut 8. ing. Note that the double-row outward-facing angular ball bearing 6 corresponds to a bearing device for supporting a pinion shaft.
[0016]
The pinion shaft 5 is provided with a pinion gear 5b at one axial end of a body portion 5a and a screw shaft portion 5c at the other axial end. A double row outward angular ball bearing 6 is externally mounted on the body 5 a of the pinion shaft 5, a coupling sleeve 7 is spline-fitted, and a nut 8 is mounted on the screw shaft 5 c of the pinion shaft 5. By screw-fitting, the double row outward angular ball bearing 6 is integrated with the pinion shaft 5 in a state where a preload is applied to the double row outward angular ball bearing 6, and the pinion shaft support device 1 is configured. ing. The coupling sleeve 7 is connected to, for example, a propeller shaft (not shown) of an automobile. Generally, in the case of transfer, the coupling sleeve 7 outputs the rotational power of the pinion shaft 5 to the propeller shaft. On the other hand, in the case of a differential, it is called a companion flange that inputs the rotational power of the propeller shaft to the pinion shaft 5.
[0017]
The pinion shaft support device 1 rotates the body 5a of the pinion shaft 5 with respect to the through hole 2a of the case 2 via the double row outward angular ball bearings 6 in a state where the pinion gear 5b is arranged inside the case 2. The double row outward angular ball bearing 6 receives the axial load and the radial load acting on the pinion shaft 5 freely.
[0018]
Next, the double-row outward-facing angular ball bearing 6 will be described in detail. This double-row outward-facing angular ball bearing 6 includes a single outer ring 10, two inner rings 11 and 12, a plurality of balls 13, and two retainer rings 14 and 15.
[0019]
The outer race 10 has two rows of raceways 10a, 10b in the axial direction, counter bores 10c, 10d at both ends in the axial direction, and a flange 10e extending radially outward at the outer diameter portion. . The outer ring 10 is fitted into the through hole 2 a of the case 2, and its flange 10 e is fixed to the case 2 with a bolt 9. An O-ring 3 is interposed on a fitting surface between the outer ring 10 and the through hole 2a of the case 2. The first inner race 11 has a single raceway surface 11a that is paired with one raceway surface 10a of the outer race 10, and has a counter bore 11b at the inner end in the axial direction. The second inner race 12 has a single raceway surface 12a that is paired with the other raceway surface 10b of the outer race 10, and has a counter bore 12b at the inner end in the axial direction. These two inner rings 11 and 12 are fitted to the body 5 a of the pinion shaft 5. The ball 13 is interposed between the two rows of raceways 10a, 10b of the outer race 10 and the raceways 11a, 12a of the two inner races 11, 12. The retainer rings 14 and 15 are so-called crown-shaped, and are configured to arrange the plurality of balls 13 arranged in the two rows at substantially equal circumferential intervals.
[0020]
The double-row outward-facing angular ball bearing 6 is designed to be different from a general standard product in consideration of use conditions in transfer and differential, and will be described in detail below.
[0021]
In the first place, in the case of a double row outward-facing angular contact ball bearing of a general standard product, the nominal contact angle α of the ball 13 is set to 20 degrees or more and 25 degrees or less, and the curvature of each raceway surface 10a, 10b of the outer ring 10 The radii R1 and R2 are not less than 52.5% and not more than 53% of the diameter r of the ball 13, and the curvature radii R3 and R4 of the raceway surfaces 11a and 12a of the inner rings 11 and 12 are 51.5% of the diameter r of the ball 13. % To 52.5% or less.
[0022]
On the other hand, in the present embodiment, the nominal contact angle α of the ball 13 is set within a range of 30 degrees or more, preferably 35 degrees or more and 45 degrees or less, and the radius of curvature of each of the raceway surfaces 10 a and 10 b of the outer ring 10. R1 and R2 are 51.0% or more and 52% or less of the diameter r of the ball 13, preferably 51.2% or more and 51.8% or less, and the radius of curvature R3 of the raceway surfaces 11a and 12a of the inner rings 11 and 12 is further increased. , R4 are set to 50.2% or more and 51.2% or less, preferably 50.5% or more and 51% or less of the diameter r of the ball 13.
[0023]
As described above, if the nominal contact angle α is set to be larger than the general value, the load capacity in the axial direction can be increased, and the curvature radii R1 to R4 can be set to be larger than the general value. If it is set small, the load resistance and durability of the double-row outward-facing angular ball bearing 6 can be enhanced, for example, the indentation of the outer ring 10 and the two inner rings 11 and 12 by the ball 13 can be suppressed. it can.
[0024]
In addition, with respect to the two inner rings 11, 12, the maximum thickness is made larger than that of a general standard product, and the outer diameter of the bottom center of the raceway surfaces 11a, 12a and the outer diameter of the shoulder are made as small as possible. The outer diameter of the counter bores 11b and 12b is set as small as possible while being set to be large (formed relatively thicker than that of the outer ring 10). By doing so, the pitch circle diameter (PCD) of the balls 13 can be made as large as possible, so that the number of balls 13 used can be increased and the load capacity can be increased. In addition, the step (or the amount of step drop) from the raceway surfaces 11a, 12a to the counter bores 11b, 12b increases, so that the facing annular space between the outer ring 10 and the two inner rings 11, 12 can be increased, and the grease can be increased. The amount of encapsulation can be increased.
[0025]
Moreover, the double-row outward-facing angular ball bearing 6 is not lubricated with the oil accommodated in the case 2 but is lubricated with grease, and will be described below.
[0026]
That is, by attaching contact type seals 20 and 30 to both ends in the axial direction of the outer ring 10, the opposed annular space (bearing internal space) between the outer ring 10 and the two inner rings 11 and 12 is sealed. A predetermined amount of grease (not shown) is sealed in the space.
[0027]
Further, a slinger 40 having a U-shaped cross section is provided further outside the seal 30 on the tail side. The slinger 40 has its inner peripheral portion fixed to the outer peripheral surface of the coupling sleeve 7 by press-fitting, and its outer peripheral portion faces the inner peripheral surface of the outer end portion of the outer ring 10 via a small gap. Form a labyrinth seal (non-contact sealing portion).
[0028]
The seal 20 disposed on the head side (pinion gear 5b side) is generally of a type called an oil seal, and the seal 30 disposed on the tail side (opposite pinion gear 5b side) is a bearing. It is a type called a seal.
[0029]
More specifically, the two seals 20 and 30 have a configuration in which elastic bodies 22 and 32 such as rubber are vulcanized and bonded to annular cores 21 and 31. The annular metal cores 21 and 31 have a shape in which annular plate portions 21b and 31b extending radially inward are provided at one axial end of the cylindrical portions 21a and 31a. The elastic bodies 22 and 32 include a wrapping part (reference numeral omitted) covering the outer periphery of the cylindrical parts 21a and 31a of the annular cores 21 and 31 from one side of the annular plate parts 21b and 31b, and the annular plate parts 21b and 31b. And lips 23 and 33 protruding from the inner periphery of the lip. The lips 23, 33 have a shape that can be opened toward the outside of the bearing so as to mainly prevent foreign matter from entering from outside the bearing.
[0030]
In each of the seals 20 and 30, the cylindrical portions 21a and 31a of the annular cores 21 and 31 are press-fitted into the two counter bores 10c and 10d of the outer race 10 via the wrapping portions of the elastic members 22 and 32, respectively. It is fixed by being combined. With the seals 20 and 30 fixed in this manner, the lips 23 and 33 thereof are brought into contact with the shoulders of the two inner rings 11 and 12 on the inner periphery with a predetermined binding force.
[0031]
Further, the head side seal 20 is configured to forcibly press the lip 23 against the first inner ring 11 by the spring ring 24 so that the sealing property is enhanced as much as possible. It can be strongly prevented from entering the inside.
[0032]
On the other hand, the tail side seal 30 does not use a spring ring or the like, but simply sets the inner diameter of the lip 33 to be smaller than the outer diameter of the shoulder of the inner ring 12 by a predetermined amount. The inner ring 12 is brought into contact with the inner ring 12 in an expanded state.
[0033]
Further, a ventilation groove 34 extending in the axial direction is provided at one position on the circumference of the outer diameter portion of the tail-side seal 30 as a ventilation portion for communicating the inside and outside of the bearing. The ventilation groove 34 is provided for the cylindrical portion 31a of the annular core 31. The envelope portion of the elastic body 32 attached to the cylindrical portion 31a is covered so as to follow the outer diameter of the cylindrical portion 31a. Is being worn. In this case, when the double-row outward-facing angular ball bearing 6 is cooled from a high-temperature state to a low-temperature state, the pressure inside the bearing becomes lower than the external pressure. Since the pressure difference between the inside and outside of the bearing can be eliminated by the venting action between the inside and outside of the bearing by the groove 34, the phenomenon that the lip 33 of the tail side seal 30 is strongly pressed against the shoulder of the inner ring 12 (so-called sticking phenomenon) is prevented. Can be prevented.
[0034]
Incidentally, as the elastic bodies 22 and 32 of the seals 20 and 30, acrylic rubber, heat-resistant acrylic rubber, or the like is suitably used. The heat-resistant acrylic rubber is an ethylene-acrylic rubber in which ethylene and an acrylate are combined as main components of a copolymer composition.
[0035]
The grease sealed inside the double-row outward-facing angular ball bearing 6 is preferably a diurea-based grease or an ester-based grease having good compatibility with gear oil in consideration of heat resistance. As this grease, specifically, for example, a product called KNG170 (trade name, manufactured by Nippon Grease Co., Ltd.) or Multemp SRL (trade name, manufactured by Kyodo Yushi Co., Ltd.) is suitably used. The above KNG170 uses a base oil of polyalphaolefin mineral oil and a thickener of diurea, and has a working temperature range of -30C to 150C. The Multemp SRL uses an ester as the base oil and a lithium soap as the thickener, and has a working temperature range of -40C to 130C.
[0036]
As described above, since the double-row outward-facing angular ball bearing 6 is used to support the pinion shaft 5, the rolling resistance is smaller than when a tapered roller bearing is used, which is advantageous in reducing the torque. . In addition, for the double-row outward-facing angular ball bearing 6, the nominal contact angle α, the radii of curvature R1, R2 of the raceways 10a, 10b of the outer race 10, and the radii of curvature R3, R4 of the raceways 11a, 12a of the inner races 11, 12 are provided. Is different from general standard products so that the usage conditions in transfer and differential are cleared and sufficient load resistance and durability are secured. Further, by forming the double-row outward-facing angular ball bearing 6 into a form which is sealed with seals 20 and 30 and lubricated with grease, the oil in the case 2 to which the pinion shaft 5 is to be used is prevented from being introduced inside. Therefore, the problems related to the oil as pointed out in the conventional example are eliminated. In other words, the use of grease lubrication makes it possible to suppress an increase in torque due to oil agitation resistance and to reduce the size and weight of the transfer and differential, for example, because there is no need to form an oil introduction path or an oil return path in the case 2. In addition to the above, since it is not affected by foreign matter in oil as in the case of oil lubrication, it is possible to contribute to the improvement of the life of the double-row outward-facing angular ball bearing 6 and the maintenance-free operation.
[0037]
From these facts, in the pinion shaft support device 1 of this embodiment, the torque of the pinion shaft 5 can be reduced as compared with the conventional example, and it is possible to contribute to the improvement of transfer and differential efficiency.
[0038]
In addition, as in the above embodiment, the pinion shaft 5 and the double-row outward-facing angular ball bearing 6 are unitized to constitute the pinion shaft support device 1, so that the transfer or differential case to be used is used. The time and effort required for assembling into the device 2 is reduced, and the assembling property is improved.
[0039]
Hereinafter, another embodiment of the present invention will be described.
[0040]
(1) Regarding the seal 20 on the head side, as shown in FIG. 4, a wrapping portion of the elastic body 22 is provided on the inner peripheral surface of the cylindrical portion 21a of the annular core 21, and the cylindrical portion 21a of the annular core 21 is The outer ring 10 is directly press-fitted into the counter bore 10c. The counterbore 10c of the outer race 10 is polished to a smooth finish, so that the sealing surface of the fitting surface with the annular core 21 is enhanced. In this case, the mounting position accuracy of the head-side seal 20 is improved, and interference with the ball 13 can be reliably avoided.
[0041]
(2) As shown in FIG. 5, the tail-side seal 30 can be combined with a slinger 50 to form a so-called pack seal. The lip 33 of the seal 30 is in contact with the outer peripheral surface of the cylindrical portion 51 of the slinger 50 with a predetermined binding force, and the foreskin portion covering the annular plate portion 31b of the seal 30 is the annular plate portion 52 of the slinger 50. And a small gap therebetween. In this case, even when water is applied from the outside, the effect of preventing water from entering the inside of the bearing is increased, and protection of the seal 30 is prevented, for example, the presence of the slinger 50 can prevent water from directly touching the seal 30. Becomes possible.
[0042]
(3) In the above embodiment, in order to integrate the pinion shaft 5 and the double-row outward-facing angular ball bearing 6, the nut 8 is screwed to the screw shaft portion 5 c of the pinion shaft 5. However, the following may be performed. In other words, the pinion shaft 5 is not provided with the screw shaft portion 5c, but the pinion shaft 5 is formed into a cylindrical shape on the side opposite to the pinion gear 5b, and the cylindrical portion is rolled and swaged outward in a radially outward direction. A structure in which the pinion shaft 5 and the double-row outward-facing angular ball bearing 6 are integrated at the swaged portion can be provided.
[0043]
【The invention's effect】
In the bearing device for supporting a pinion shaft according to the present invention, the torque of the pinion shaft can be reduced as compared with the conventional example while reducing the size and weight.
[0044]
ADVANTAGE OF THE INVENTION In the pinion shaft support device of this invention, while being small and lightweight, it is possible to achieve a lower torque of the pinion shaft as compared with the conventional example, and also to simplify the assembling to a use object.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view showing a pinion shaft support device according to an embodiment of the present invention. FIG. 2 is an enlarged view showing an upper half of a double-row outward-facing angular ball bearing in FIG. FIG. 4 is a perspective view showing an application example of the head side seal in FIG. 1; FIG. 5 is a perspective view showing an application example of the tail side seal in FIG. 1;
DESCRIPTION OF SYMBOLS 1 Pinion shaft support device 5 Pinion shaft 5a Pinion shaft body 5b Pinion gear 5c Pinion gear screw shaft 6 Double row outward angular ball bearing 10 Outer rings 11, 12 Inner ring 20 Head side seal 30 Tail side seal

Claims (4)

A bearing device for supporting a body of a pinion shaft having a pinion gear at one end,
A bearing device for supporting a pinion shaft, wherein the bearing is a double-row outward-facing angular ball bearing, and grease is sealed in a bearing internal space sealed at both ends in the axial direction with a seal. The double-row outward-facing angular contact ball bearing has a single outer ring having two rows of raceways in the axial direction and having counter bores at both axial ends, and a single outer ring paired to one raceway of the outer ring. A first inner race having a raceway surface and having a counter bore at an axial inner end, a single raceway surface paired with the other raceway surface of the outer race, and having a counter bore at an axial inner end. A configuration including a second inner ring, and a plurality of balls interposed between two rows of raceways of the outer race and raceways of the two inner races,
The contact angle of the ball is set to 30 degrees or more and 45 degrees or less, the radius of curvature of each raceway surface of the outer ring is set to 51.0% or more and 52% or less of the diameter of the ball, and each of the inner rings is set. 2. The bearing device for supporting a pinion shaft according to claim 1, wherein the radius of curvature of the raceway surface is set to 50.2% or more and 51.2% or less of the diameter of the ball. Each of the seals has an outer peripheral portion attached to the two counter bores of the outer ring, and has a shape that can be brought into contact with the shoulders of the two inner rings on the inner periphery and open outward from the bearing. The seal disposed on the pinion gear side is such that the lip is forcibly pressed against the shoulder of the inner ring by a spring ring. The bearing device for supporting a pinion shaft according to claim 1 or 2, further comprising a ventilation portion that communicates with the pinion shaft. A pinion shaft having a pinion gear at one end and a screw shaft at the other end, a double-row outward-facing angular ball bearing externally mounted on the body of the pinion shaft, and screwed to the screw shaft of the pinion shaft; A nut that integrates a double-row outward-facing angular contact ball bearing with the pinion shaft,
A pinion shaft support device, wherein the double-row outward-facing angular ball bearing has grease sealed in a bearing internal space sealed by seals mounted on both ends in the axial direction.

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