Bearing device for wheel

Abstract

The purpose of the present invention is to improve workability in assembling an outer joint member of a constant-velocity universal joint to a hub ring in a bearing device for a wheel. A bearing device 1 for a wheel is configured such that an inner end surface of a crimped part 3f of a hub ring 3 and an outer end surface of a shoulder part 26 of an outer joint member 21 are spline-fitted together, and comprises a cylindrical cover member 32 that covers the outer periphery of the spline fitting of the inner end surface of the crimped part 3f of the hub ring 3 and the outer end surface of the shoulder part 26 of the outer joint member 21, the cover member 32 being configured from a heat-shrinkable material that shrinks when heated.

Description

Wheel bearing device

[0001] The present invention relates to a wheel bearing device.

[0002] Conventionally, an outer member, an inner member with an inner ring fixed to a hub ring, a double row of rolling elements rotatably accommodated between both raceway surfaces of the outer member and the inner member, and an outer joint member of a constant velocity joint having a mouse portion connected to the shaft so as to be rotationally transmissible are provided. A wheel bearing device in which the end surface of the hub ring and the end surface of the outer joint member are spline-fitted is known.

[0003] Patent Document 1 describes a bearing device for a wheel boss of an automobile that can be driven via a rotary joint. In the bearing device for the wheel boss of the automobile described in Patent Document 1, a wheel boss coupled to a wheel flange and a rotary joint coupled to a drive shaft are coupled by a toothed portion so as not to rotate relative to each other. A two-row rolling bearing having at least one separate inner race of the bearing mounted on the wheel boss and provided axially outward and facing the rotary joint is provided. The inner race of the bearing is provided at the end of the shaft end of the wheel boss in the range of its axially outer end surface, and a preload is applied axially by the radial surface of the wheel boss acting on the end surface of the separate inner race of the bearing. The outer race and the inner race of the bearing are provided with a sealing device. This sealing device has a sealing ring coupled to the inner race of the bearing. This sealing ring has one radial leg and one axial leg in cross section. The axial leg is coupled so as not to rotate relative to the inner race of the bearing, and is directed axially inward. The axial leg of the sealing ring of the inner race of the bearing is bent radially inward and axially outward, and the free end of the axial leg protrudes axially outward from the end surface of the inner race of the bearing. Further, the free end of the sealing ring in this sealing device is extended so as to be an end leg extending axially. This end leg is provided radially above the toothed portion and on the step portion of the outer joint body of the rotary joint. A sealing deformable material is provided on the end leg, and the sealing deformable material abuts against the step portion and the edge of the outer joint body. Thus, the toothed portion is sealed and protected.

[0004] Japanese Patent Publication No. 2009-543009

[0005] However, in the wheel boss bearing device for automobiles described in Patent Document 1, since it is necessary to ensure the sealing of the toothed portion, it is conceivable that the sealing profile of the sealing device is in contact with the outer joint body with a predetermined pressing force. In this case, when assembling the rotary joint to the wheel boss, if the wheel boss and rotary joint are moved in a direction toward proximity, the sealing profile will slide while pressing against the outer joint body. This has sometimes caused problems with the workability when assembling the rotary joint to the wheel boss.

[0006] Therefore, the present invention aims to provide a wheel bearing device that can improve the workability when assembling the outer joint member of a constant velocity universal joint to a hub wheel.

[0007] Specifically, the wheel bearing device comprises an outer member having double rows of outer raceway surfaces on its inner circumference, a hub ring having an outer circumference extending in the axial direction, and at least one inner ring press-fitted onto the outer circumference of the hub ring, wherein the inner ring is fixed to the hub ring by a crimped portion formed by crimping the other axial end of the hub ring toward the inner ring, and the inner member having double rows of inner raceway surfaces facing the double rows of outer raceway surfaces, double rows of rolling elements rotatably housed between the two raceway surfaces of the outer member and the inner member, a mouth portion that is rotatably connected to a shaft, and an outer joint member having a shoulder portion located on one axial side of the mouth portion and forming the bottom of the mouth portion, wherein the other axial end surface of the crimped portion and the one axial end surface of the shoulder portion are spline-fitted, and further comprises a cylindrical cover member that covers the outer circumference of the spline-fitted portion between the crimped portion and the shoulder portion, the cover member being made of a heat-shrinkable material that shrinks when heated.

[0008] The present invention provides the following effects. Specifically, the present invention improves the workability when assembling the outer joint member of a constant velocity universal joint to a hub wheel.

[0009] A cross-sectional view showing a wheel bearing device according to one embodiment of the present invention. An enlarged cross-sectional view showing the state in which the cover member has not been heated to its shrinkage temperature at the spline fitting portion between the crimped portion of the hub ring of the wheel bearing device and the shoulder portion of the outer joint member of the constant velocity universal joint. An enlarged cross-sectional view showing the state in which the cover member has been heated to its shrinkage temperature and shrunk at the spline fitting portion between the crimped portion of the hub ring of the wheel bearing device and the shoulder portion of the outer joint member of the constant velocity universal joint. An enlarged cross-sectional view showing the state in which the cover member has not been heated to its shrinkage temperature at the spline fitting portion between the crimped portion of the hub ring of the wheel bearing device and the shoulder portion of the outer joint member of the constant velocity universal joint. An enlarged cross-sectional view showing the state in which the cover member has been heated to its shrinkage temperature and shrunk at the spline fitting portion between the crimped portion of the hub ring of the wheel bearing device and the shoulder portion of the outer joint member of the constant velocity universal joint.

[0010] The embodiments for carrying out the present invention will be described below with reference to the attached drawings.

[0011] [Overall Configuration of Wheel Bearing Device] The wheel bearing device 1 shown in Figure 1 is one embodiment of the wheel bearing device according to the present invention, and is used to rotatably support a wheel in the suspension system of a vehicle such as an automobile.

[0012] As shown in Figure 1, the wheel bearing device 1 has a configuration referred to as the third generation, and comprises an outer ring 2 which is an outer member, a hub ring 3 and an inner ring 4 which are inner members, two rows of inner ball rows 5 and outer ball rows 6 which are rolling rows, an inner sealing member 9, an outer sealing member 10, and an outer joint member 21 of a constant velocity universal joint 20.

[0013] Here, "inner side" refers to the side of the wheel bearing device 1 that is attached to the vehicle body, and "outer side" refers to the side of the wheel bearing device 1 that is attached to the vehicle body. Furthermore, "axial direction" refers to the direction along the rotation axis X of the wheel bearing device 1, with one axial side being the outer side and the other axial side being the inner side. Furthermore, the direction perpendicular to the rotation axis of the wheel bearing device 1 is referred to as the radial direction. In the following, "cross-section" will be described as a cross-section that passes through the rotation axis of the wheel bearing device 1 and is parallel to the rotation axis of the wheel bearing device 1.

[0014] The inner circumferential surface of the outer ring 2 has an inner outer raceway groove 2c and an outer outer raceway groove 2d formed thereon.

[0015] A small-diameter stepped portion 3a, smaller in diameter than the outer end, is formed on the inner end of the outer circumferential surface of the hub wheel 3. A wheel mounting flange 3b for attaching a wheel is integrally formed on the outer end of the hub wheel 3. Multiple bolt holes 3d are formed in the wheel mounting flange 3b. Wheel bolts are screwed into the bolt holes 3d from the wheel side to fasten the hub wheel 3 to the wheel or brake components. Alternatively, the fastening structure between the hub wheel 3 and the wheel or brake components may be fixed by press-fitting hub bolts and nuts.

[0016] The outer surface of the hub ring 3 is provided with an inner raceway groove 3c on the outer side, facing the outer raceway groove 2d on the outer side of the outer ring 2. In other words, the inner raceway groove 3c is formed on the outer side of the inner member by the hub ring 3. The hub ring 3 has a through hole 3e that penetrates axially through its inner diameter. The shaft portion 27 of the outer joint member 21 of the constant velocity universal joint 20 is inserted into the through hole 3e. An annular space, the outer side opening 2b, is formed between the outer ring 2 and the hub ring 3. The outer side sealing member 10 is fitted into the outer side opening 2b and prevents foreign matter such as muddy water from entering through the outer side opening 2b. The outer side sealing member 10 is an example of a sealing device.

[0017] The inner ring 4 is provided on the small-diameter stepped portion 3a of the hub ring 3. The inner ring 4 is press-fitted into the small-diameter stepped portion 3a via a predetermined crimping allowance. Furthermore, the inner end of the small-diameter stepped portion 3a on the hub ring 3 is plastically deformed by crimping toward the inner ring 4, thereby integrating the hub ring 3 and the inner ring 4 and preventing the inner ring 4 from coming out axially relative to the hub ring 3. The crimped portion 3f is crimped toward the inner end face of the inner ring 4 and protrudes inward from the inner end face of the inner ring 4. The crimped portion 3f is equipped with a face spline 3g. The face spline 3g is formed on the inner end face of the crimped portion 3f. The inner ring 4 applies preload to the rolling rows, which are the inner ball row 5 and the outer ball row 6. An inner raceway groove 4a is provided on the outer circumferential surface of the inner ring 4 so as to face the outer raceway groove 2c on the inner side of the outer ring 2. In other words, an inner raceway groove 4a is formed on the inner side of the inner member by the inner ring 4. An annular space, the inner side opening 2a, is formed between the outer ring 2 and the inner ring 4. The inner side sealing member 9 is fitted into the inner side opening 2a and prevents foreign matter such as muddy water from entering through the inner side opening 2a. The inner side sealing member 9 is an example of a sealing device.

[0018] The inner ball row 5 and the outer ball row 6, which are rolling elements, are composed of multiple balls 7, which are rolling elements, held by a cage 8. The inner ball row 5 is rotatably sandwiched between the inner raceway groove 4a of the inner ring 4 and the inner outer raceway groove 2c of the outer ring 2. The outer ball row 6 is rotatably sandwiched between the inner raceway groove 3c of the hub ring 3 and the outer outer raceway groove 2d of the outer ring 2. In other words, the inner ball row 5 and the outer ball row 6 are rotatably housed between the raceway grooves of the outer and inner members. In the wheel bearing device 1, a double-row angular contact ball bearing is composed of the outer ring 2, the hub ring 3 and the inner ring 4, the inner ball row 5 and the outer ball row 6.

[0019] The constant velocity universal joint 20 is provided at one end of the shaft 12 (intermediate shaft). The constant velocity universal joint 20 is connected to the shaft 12 so that rotational torque from the shaft 12 can be transmitted. The constant velocity universal joint 20 includes an outer joint member 21, an inner joint member 22 having a track groove formed on its outer circumference opposite to the track groove of the outer joint member 21, a ball 23 incorporated between the track groove of the outer joint member 21 and the track groove of the inner joint member 22, and a cage 24 interposed between the inner circumference of the outer joint member 21 and the outer circumference of the inner joint member 22 to hold the ball 23. The cage 24 is a retainer for holding the ball 23.

[0020] The outer joint member 21 of the constant velocity universal joint 20 comprises a mouth portion 25, a shoulder portion 26, a shaft portion 27, and a face spline 28.

[0021] The mouth portion 25 of the outer joint member 21 of the constant velocity universal joint 20 is configured in a bowl shape that decreases in diameter towards the outer side. The shoulder portion 26 is located on the outer side (one side in the axial direction) of the mouth portion 25 and constitutes the bottom of the mouth portion 25. The outer diameter of the shoulder portion 26 is smaller than the outer diameter of the mouth portion 25. The shaft portion 27 is configured in a cylindrical shape and extends from the shoulder portion 26 towards the outer side. The face spline 28 is formed on the outer end face of the shoulder portion 26. The face spline 28 fits onto the face spline 3g of the crimp portion 3f of the hub ring 3.

[0022] The shaft portion 27 of the outer joint member 21 of the constant velocity universal joint 20 is inserted into the through hole 3e of the hub wheel 3. A female thread is formed on the inner circumferential surface of the shaft portion 27. By screwing the fastening bolt 11 into the female thread of the shaft portion 27, the face spline 3g of the crimped portion 3f of the hub wheel 3 and the face spline 28 of the shoulder portion 26 of the outer joint member 21 are held in a fitted state, and torque from the shaft 12 can be transmitted to the hub wheel 3 via the outer joint member 21.

[0023] [Cover] As shown in Figures 1 to 3, the wheel bearing device 1 further includes a cover 30. The cover 30 is configured to cover the outer circumference of the spline fitting portion between the crimped portion 3f of the hub wheel 3 and the shoulder portion 26 of the outer joint member 21 of the constant velocity universal joint 20 (the portion where the face spline 3g of the crimped portion 3f of the hub wheel 3 and the face spline 28 of the shoulder portion 26 of the outer joint member 21 of the constant velocity universal joint 20 are fitted together). The cover 30 protects the spline fitting portion by preventing foreign matter such as muddy water from entering the spline fitting portion between the crimped portion 3f of the hub wheel 3 and the shoulder portion 26 of the outer joint member 21 of the constant velocity universal joint 20. The cover 30 is configured separately from the inner side seal member 9. The cover 30 includes a slinger 31 and a cover member 32.

[0024] The slinger 31 of the cover 30 is configured in a substantially annular shape. The slinger 31 is configured separately from the inner side sealing member 9. The slinger 31 is fitted onto the inner ring 4 on the inner side of the inner side sealing member 9. The slinger 31 is formed from a metal member, for example, made of steel, and has a substantially L-shaped cross-section. The slinger 31 has an outer fitting portion 31a and a side plate portion 31b.

[0025] The outer fitting portion 31a of the slinger 31 of the cover 30 is cylindrical. The outer fitting portion 31a of the slinger 31 is fitted onto the outer circumference of the inner end of the inner ring 4 on the inner side of the inner side sealing member 9. The outer fitting portion 31a of the slinger 31 is configured parallel to the axial direction. The side plate portion 31b of the slinger 31 is annular and is located on the inner diameter side of the outer fitting portion 31a. The side plate portion 31b of the slinger 31 extends inward from the outer fitting portion 31a. The side plate portion 31b of the slinger 31 is configured parallel to the radial direction. The outer diameter side end of the side plate portion 31b of the slinger 31 is connected to the inner side end of the outer fitting portion 31a. The outer side surface of the side plate portion 31b of the slinger 31 is in contact with the inner end surface of the inner ring 4.

[0026] The cover member 32 of the cover 30 is cylindrical in shape and covers the outer circumference of the spline fitting portion between the crimped portion 3f of the hub ring 3 and the shoulder portion 26 of the outer joint member 21 of the constant velocity universal joint 20. The cover member 32 is made of resin material. The cover member 32 is joined to the slinger 31 by adhesive or the like. The outer end of the cover member 32 is joined to the inner side surface of the side plate portion 31b of the slinger 31. The cover member 32 extends inward from the side plate portion 31b of the slinger 31. The inner end of the cover member 32 is located on the inner side of the spline fitting portion between the crimped portion 3f of the hub ring 3 and the shoulder portion 26 of the outer joint member 21 of the constant velocity universal joint 20, and is located on the outer diameter side of the shoulder portion 26 of the outer joint member 21 of the constant velocity universal joint 20. The outer diameter of the crimped portion 3f of the hub ring 3 and the outer diameter of the shoulder portion 26 of the outer joint member 21 in the constant velocity universal joint 20 are approximately the same size.

[0027] The cover member 32 of the cover 30 is made of a heat-shrinkable material that shrinks when heated. The cover member 32 does not shrink when not heated to the shrinkage temperature, but shrinks after being heated above the shrinkage temperature. The cover member 32 is made of a material such as polyolefin resin, polyvinyl chloride resin, polyvinylidene fluoride resin, or elastomer resin. The shrinkage temperature of the cover member 32 is set to, for example, 120°C or higher.

[0028] As shown in Figure 2, the cover member 32 of the cover portion 30 is formed to have a larger diameter than the outer diameter of the crimped portion 3f of the hub wheel 3 and the outer diameter of the shoulder portion 26 of the outer joint member 21 of the constant velocity universal joint 20 when it has not been heated to its shrinkage temperature. When the cover member 32 has not been heated to its shrinkage temperature, there is a gap between the outer circumferential surface of the crimped portion 3f of the hub wheel 3 and the outer circumferential surface of the shoulder portion 26 of the outer joint member 21 of the constant velocity universal joint 20. As shown in Figure 3, after the outer joint member 21 of the constant velocity universal joint 20 is assembled to the hub wheel 3, the cover member 32, which has not been heated to its shrinkage temperature, is heated to a temperature above the shrinkage temperature by a predetermined heating means such as a heater, causing the cover member 32 to shrink and reduce in diameter. In the state after being heated to a temperature above the shrinkage temperature, the cover member 32 has reduced in diameter and is in close contact with the outer circumferential surface of the crimped portion 3f of the hub wheel 3 and the outer circumferential surface of the shoulder portion 26 of the outer joint member 21 of the constant velocity universal joint 20.

[0029] As described above, the cover member 32 of the cover 30 covers the outer circumference of the spline fitting portion between the crimped portion 3f of the hub wheel 3 and the shoulder portion 26 of the outer joint member 21 of the constant velocity universal joint 20, and is made of a heat-shrinkable material that shrinks when heated. For this reason, even when the hub wheel 3 and the constant velocity universal joint 20 are moved relatively in a direction toward proximity during the assembly work of the outer joint member 21 of the constant velocity universal joint 20 to the hub wheel 3, the cover member 32 of the cover 30 does not slide while pressing against the shoulder portion 26 of the outer joint member 21 of the constant velocity universal joint 20. Therefore, the workability when assembling the outer joint member 21 of the constant velocity universal joint 20 to the hub wheel 3 can be improved.

[0030] Furthermore, as described above, when the cover member 32 of the cover 30 is not heated to its shrinkage temperature, it is formed with a larger diameter than the outer diameter of the crimped portion 3f of the hub wheel 3 and the outer diameter of the shoulder portion 26 of the outer joint member 21 of the constant velocity universal joint 20. For this reason, when assembling the outer joint member 21 of the constant velocity universal joint 20 to the hub wheel 3, even if the hub wheel 3 and the constant velocity universal joint 20 are moved relatively in a direction toward proximity, the cover member 32 of the cover 30 does not slide while pressing against the shoulder portion 26 of the outer joint member 21 of the constant velocity universal joint 20. Therefore, the workability when assembling the outer joint member 21 of the constant velocity universal joint 20 to the hub wheel 3 can be improved.

[0031] Furthermore, as described above, when the cover member 32 of the cover 30 is not heated to its shrinkage temperature, there is a gap between the outer surface of the crimped portion 3f of the hub wheel 3 and the outer surface of the shoulder portion 26 of the outer joint member 21 of the constant velocity universal joint 20. For this reason, when assembling the outer joint member 21 of the constant velocity universal joint 20 to the hub wheel 3, even if the hub wheel 3 and the constant velocity universal joint 20 are moved relatively in a direction toward proximity, the cover member 32 of the cover 30 does not slide while pressing against the shoulder portion 26 of the outer joint member 21 of the constant velocity universal joint 20. Therefore, the workability when assembling the outer joint member 21 of the constant velocity universal joint 20 to the hub wheel 3 can be improved.

[0032] Furthermore, as described above, the cover member 32 of the cover 30 is heated above its shrinkage temperature and shrinks in diameter after the outer joint member 21 of the constant velocity universal joint 20 is assembled to the hub wheel 3. At this time, when the cover member 32 is heated above its shrinkage temperature, it shrinks in diameter to a shape that corresponds to the dimensional variation of the spline fitting portion between the crimped portion 3f of the hub wheel 3 and the shoulder portion 26 of the outer joint member 21 of the constant velocity universal joint 20. Therefore, it is possible to more reliably prevent foreign matter such as muddy water from entering the spline fitting portion between the crimped portion 3f of the hub wheel 3 and the shoulder portion 26 of the outer joint member 21 of the constant velocity universal joint 20, thereby protecting the spline fitting portion.

[0033] Furthermore, as described above, when the cover member 32 of the cover 30 is heated above its shrinkage temperature, it shrinks in diameter and comes into close contact with the outer circumferential surface of the crimped portion 3f of the hub wheel 3 and the outer circumferential surface of the shoulder portion 26 of the outer joint member 21 of the constant velocity universal joint 20. Therefore, it is possible to more reliably prevent foreign matter such as muddy water from entering the spline fitting portion between the crimped portion 3f of the hub wheel 3 and the shoulder portion 26 of the outer joint member 21 of the constant velocity universal joint 20, thereby protecting the spline fitting portion. Also, for this reason, the amount of grease that is filled to improve the sealing performance of the spline fitting between the crimped portion 3f of the hub wheel 3 and the shoulder portion 26 of the outer joint member 21 of the constant velocity universal joint 20 can be relatively reduced.

[0034] Furthermore, as described above, the inner end of the cover member 32 of the cover 30 is located on the outer diameter side of the shoulder portion 26 of the outer joint member 21 of the constant velocity universal joint 20. Therefore, it is possible to more reliably prevent foreign matter such as muddy water from entering the spline fitting portion between the crimped portion 3f of the hub wheel 3 and the shoulder portion 26 of the outer joint member 21 of the constant velocity universal joint 20, thereby protecting the spline fitting portion. In addition, the inner end of the cover member 32 can also be located on the inner side of the shoulder portion 26 of the outer joint member 21 of the constant velocity universal joint 20, and on the outer diameter side of the mouth portion 25. By configuring it in this way, it is possible to more reliably prevent foreign matter such as muddy water from entering the spline fitting portion between the crimped portion 3f of the hub wheel 3 and the shoulder portion 26 of the outer joint member 21 of the constant velocity universal joint 20, thereby protecting the spline fitting portion.

[0035] Furthermore, as described above, the outer diameter of the crimped portion 3f of the hub wheel 3 and the outer diameter of the shoulder portion 26 of the outer joint member 21 of the constant velocity universal joint 20 are approximately the same size. Therefore, when the cover member 32 is heated above its shrinkage temperature, it will be able to make a more secure contact with the outer circumferential surface of the crimped portion 3f of the hub wheel 3 and the outer circumferential surface of the shoulder portion 26 of the outer joint member 21 of the constant velocity universal joint 20. Consequently, it is possible to more reliably prevent foreign matter such as muddy water from entering the spline fitting portion between the crimped portion 3f of the hub wheel 3 and the shoulder portion 26 of the outer joint member 21 of the constant velocity universal joint 20, thereby protecting the spline fitting portion.

[0036] Furthermore, as described above, the cover 30 is equipped with a slinger 31 that is fitted onto the inner ring 4. Therefore, even if the cover member 32 is made of a heat-shrinkable material that shrinks when heated, the slinger 31 can hold the cover 30 attached to the inner ring 4 while the outer joint member 21 of the constant velocity universal joint 20 can be assembled to the hub wheel 3.

[0037] Furthermore, as described above, the cover 30 (the slinger 31 of the cover 30) is constructed separately from the inner side sealing member 9, and the slinger 31 is fitted onto the inner ring 4 on the inner side of the inner side sealing member 9. Therefore, when assembling the outer joint member 21 of the constant velocity universal joint 20 to the hub wheel 3, even if the hub wheel 3 and the constant velocity universal joint 20 are moved relatively in a direction toward proximity, it is possible to prevent the inner side sealing member 9 (the contact position of the seal lip of the inner side sealing member 9) from shifting in the axial direction.

[0038] The outer fitting portion 31a of the slinger 31 of the cover 30 may be configured to be positioned so as to overlap with the inner side seal member 9 when viewed from the radial direction. By configuring it in this way, the space for arranging the outer fitting portion 31a of the slinger 31 in the inner side opening 2a can be made narrower, and the axial width of the wheel bearing device 1 can be made narrower. In this case, the inner side seal member 9 may be configured so that it does not have a slinger, and the seal lip of the inner side seal member 9 contacts the outer diameter surface of the outer fitting portion 31a of the slinger 31. By configuring the slinger 31 to also serve as the slinger of the inner side seal member 9 in this way, the number of parts of the inner side seal member 9 can be reduced. In this case, the outer fitting portion 31a of the slinger 31 may be positioned between the slinger of the inner side seal member 9 and the inner ring 4. By configuring it in this way, it is possible to prevent the position in which the seal lip of the inner side seal member 9 contacts the slinger from shifting in the axial direction.

[0039] As shown in Figures 4 and 5, the outer joint member 21 of the constant velocity universal joint 20 can also be configured to have a groove 29. The groove 29 of the outer joint member 21 is formed on the outer circumferential surface of the shoulder portion 26. The groove 29 of the outer joint member 21 is formed around the entire circumference of the outer circumferential surface of the shoulder portion 26 and is configured in an annular shape. The groove 29 of the outer joint member 21 extends along the circumferential direction of the outer circumferential surface of the shoulder portion 26. The cover member 32 of the cover 30, which is heated above its shrinkage temperature, is in close contact with the outer circumferential surface of the crimped portion 3f of the hub ring 3 and the outer circumferential surface of the shoulder portion 26 of the outer joint member 21 of the constant velocity universal joint 20, and is also in close contact with the groove 29 of the outer joint member 21 (see Figure 5).

[0040] As described above, the groove 29 of the outer joint member 21 in the constant velocity universal joint 20 is formed on the outer circumferential surface of the shoulder portion 26 and extends along the circumferential direction of the outer circumferential surface of the shoulder portion 26. The cover member 32 of the cover 30, which is heated above its shrinkage temperature, is in close contact with the groove 29 of the outer joint member 21. Therefore, it is possible to suppress excessive shrinkage of the cover member 32 of the cover 30, which is heated above its shrinkage temperature, and prevent the spline fitting portion between the crimped portion 3f of the hub ring 3 and the shoulder portion 26 of the outer joint member 21 in the constant velocity universal joint 20 from being exposed. Note that the groove 29 of the outer joint member 21 of the constant velocity universal joint 20 is not limited to being formed across the outer circumferential surface of the shoulder portion 26, but may be configured intermittently, for example.

[0041] Although a wheel bearing device referred to as the third generation has been given as an example, the wheel bearing device according to the present invention is not limited to such a structure. For example, instead of forming an inner raceway groove in the inner ring opposite to the outer raceway groove of the outer ring, a pair of inner rings may be press-fitted into the small-diameter stepped portion of the hub ring, which is a second-generation structure. Alternatively, a constant-velocity universal joint that fits into the through hole of the hub ring may be formed, resulting in a fourth-generation structure without an inner ring. In this case, the constant-velocity universal joint becomes a raceway groove forming member connected to the hub ring.

[0042] Although embodiments of the present invention have been described above, the present invention is not limited in any way to these embodiments, but is merely illustrative. It can be implemented in various other forms without departing from the spirit of the invention, and the scope of the present invention is indicated by the claims, and further includes all modifications within the meaning and scope of equivalents as described in the claims.

[0043] This invention can be used in wheel bearing devices.

[0044] 1 Wheel bearing device 2 Outer member 2a Inner opening 2b Outer opening 3 Inner member 3a Small diameter stepped section 3h Crimping section 3g Face spline 4 Inner ring 5 Inner ball row 6 Outer ball row 8 Cage 9 Inner sealing member 10 Outer sealing member 20 Constant velocity universal joint 21 Outer joint member 22 Inner joint member 23 Ball 24 Cage 25 Mouth section 26 Shoulder section 27 Shaft section 28 Face spline 29 Groove 30 Cover 31 Slinger 31a Outer fitting section 32a Side plate section 32 Cover member

Claims

1. A wheel bearing device comprising: an outer member having double rows of outer raceway surfaces on its inner circumference; a hub ring having an outer circumference extending in the axial direction; and at least one inner ring press-fitted onto the outer circumference of the hub ring, wherein the inner ring is fixed to the hub ring by a crimped portion formed by crimping the other axial end of the hub ring toward the inner ring, and the inner member having double rows of inner raceway surfaces facing the double rows of outer raceway surfaces; double rows of rolling elements rotatably housed between the two raceway surfaces of the outer member and the inner member; a mouth portion that is rotatably connected to a shaft; and an outer joint member having a shoulder portion located on one axial side of the mouth portion and forming the bottom of the mouth portion, wherein the other axial end surface of the crimped portion and the one axial end surface of the shoulder portion are spline-fitted, and further comprising a cylindrical cover member that covers the outer circumference of the spline-fitted portion between the crimped portion and the shoulder portion, wherein the cover member is made of a heat-shrinkable material that shrinks when heated.

2. The wheel bearing device according to claim 1, wherein the cover member is formed to have a larger diameter than the outer diameter of the crimped portion and the outer diameter of the shoulder portion when not heated to the shrinkage temperature, and shrinks in diameter and adheres closely to the outer circumferential surface of the crimped portion and the outer circumferential surface of the shoulder portion when heated above the shrinkage temperature.

3. The wheel bearing device according to claim 1 or claim 2, wherein a groove extending in the circumferential direction is formed on the outer circumferential surface of the shoulder portion, and the cover member is in close contact with the groove.

Images