Wheel bearing device

Abstract

In a wheel bearing device in which the outer circumferential surface of the hub ring and the inner circumferential surface of the outer joint member are spline-fitted, the axial dimension is shortened and the weight is reduced. [Solution] The outboard end of the cylindrical portion 31 of the outer joint member 21 is brought into contact with the inner ring 14 from the inboard side, and these contact portions P are provided on the inner circumference of the inner ring 14. As a result, at least a part of the cylindrical portion 31 is positioned on the inner circumference of the inner ring 14, which shortens the axial dimension of the wheel bearing device 1 and reduces its weight.

Description

Technical Field

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

Background Art

[0002] FIG. 3 shows a wheel bearing device 100 shown in Patent Document 1 below. This wheel bearing device 100 includes a wheel bearing 110 and a constant velocity joint 120. The wheel bearing 110 has an outer member 102 attached to the vehicle body and an inner member 103 attached to the wheel. The constant velocity joint 120 has an outer joint member 121 attached to the inner member 103 of the wheel bearing 110, an inner joint member 122 attached to an intermediate shaft 140 of the drive shaft, and balls 123 that transmit torque therebetween. The outer joint member 121 has a cup-shaped mouth portion 121a and a stem portion 121b extending from the mouth portion 121a toward the outboard side (left side in the figure).

[0003] The inner member 103 of the wheel bearing 110 includes a hub ring 106 and an inner ring 107. The inner ring 107 is fitted to the outer peripheral surface of the end portion on the inboard side (right side in the figure) of the hub ring 106. With the male spline portion provided on the outer periphery of the stem portion 121b of the outer joint member 121 and the female spline portion provided on the inner periphery of the hub ring 106 being fitted together, by tightening a nut 130 screwed onto the outboard side end portion of the stem portion 121b, the outer joint member 121 and the hub ring 106 are coupled so as to be torque-transmittable. At this time, since the mouth portion 121a of the outer joint member 121 is in contact with the inner ring 107 from the inboard side, by tightening the nut 130, the inner ring 107 can be pushed toward the outboard side by the outer joint member 121 to apply preload to the wheel bearing 110.

[0004] When a vehicle starts moving, torque is applied to the wheel bearing device 100, generating a force that attempts to rotate the hub wheel 106 attached to the stationary wheel relative to the constant velocity universal joint 120 powered by the drive source. This rotational force applies a torsional force to the stem portion 121b of the outer joint member 121. Consequently, if a torque exceeding a certain amount is applied to the wheel bearing device 100, twisting occurs in the stem portion 121b of the outer joint member 121, causing slippage at the contact portion P1 between the outer joint member 121 and the inner ring 107, which can result in abnormal noise (stick-slip noise).

[0005] For example, Patent Document 2 below discloses measures to reduce the stick-slip noise described above. The wheel bearing device 200 shown in the same document comprises a wheel bearing 210 and a constant velocity universal joint 220, as shown in Figure 4. The outer joint member 221 of the constant velocity universal joint 220 is provided with a cylindrical portion 223 that protrudes outboard from the mouse portion 221a, and the outboard end of the cylindrical portion 223 is in contact with the inner ring 207. Torque can be transmitted between the two by fitting together a female spline portion formed on the inner circumference of the cylindrical portion 223 and a male spline portion formed on the outer circumference of the inboard end of the hub ring 206.

[0006] As described above, in the wheel bearing device 200 of Figure 4, since the spline fitting portion S2 is provided on the outer circumference of the hub ring 206, the diameter can be made larger than that of the spline fitting portion S1 of the wheel bearing device 100 of Figure 3, which is provided on the inner circumference of the hub ring 106. This increases the torsional rigidity of the spline fitting portion S2, thereby suppressing torsional deformation of the outer joint member and reducing slippage at the contact portion P2 between the outer joint member and the inner ring. Furthermore, in the wheel bearing device 200 of Figure 4, the spline fitting portion S2 and the contact portion P2 can be positioned in close proximity, so the relative rotational displacement (slippage) between the outer joint member 221 and the inner ring 207 at the contact portion P2 becomes extremely small. As a result, stick-slip noise at the contact portion P2 between the outer joint member 221 and the inner ring 207 can be suppressed. [Prior art documents] [Patent Documents]

[0007] [Patent Document 1] Japanese Patent Publication No. 2024-30120 [Patent Document 2] Japanese Patent Publication No. 2009-248789 [Overview of the project] [Problems that the invention aims to solve]

[0008] However, in the wheel bearing device 200 shown in Figure 4, the cylindrical portion 223 of the outer coupling member 221 is brought into contact with the inner ring 207 from the inboard side, and these are arranged in a line in the axial direction. As a result, the axial dimension of the wheel bearing device 200 increases, and the weight increases.

[0009] Therefore, the present invention aims to shorten the axial dimension and reduce the weight in a wheel bearing device in which the outer circumferential surface of a hub ring and the inner circumferential surface of an outer joint member are spline-fitted. [Means for solving the problem]

[0010] To solve the aforementioned problems, the present invention provides a wheel bearing comprising: an outer member having first and second outer raceway surfaces formed on its inner circumferential surface; an inner member having first and second inner raceway surfaces formed on its outer circumferential surface; a first rolling element row consisting of a plurality of rolling elements rotatably disposed between the first outer raceway surface and the first inner raceway surface; and a second rolling element row consisting of a plurality of rolling elements rotatably disposed between the second outer raceway surface and the second inner raceway surface. A wheel bearing device comprising a constant velocity universal joint having an outer joint member fixed to the inner member, The inner member comprises an inner ring having the second inner raceway surface formed on its outer circumferential surface, and a hub ring having an inner ring fitting surface into which the inner circumferential surface of the inner ring fits, and a male spline portion formed on its outer circumferential surface. The outer joint member has a cylindrical portion on its inner circumferential surface which has a female spline portion that fits with the male spline portion. The outboard end of the cylindrical portion of the outer joint member abuts against the inner ring from the inboard side. The present invention provides a wheel bearing device in which the contact portion between the cylindrical portion of the outer joint member and the inner ring is provided on the inner circumference of the inner ring.

[0011] As described above, in the wheel bearing device of the present invention, the contact portion between the cylindrical portion of the outer coupling member and the inner ring is provided on the inner circumference of the inner ring. As a result, at least a part of the cylindrical portion is positioned on the inner circumference of the inner ring, which allows for a reduction in the axial dimension of the wheel bearing device and a reduction in weight compared to conventional wheel bearing devices (see Figure 4) in which the cylindrical portion of the outer coupling member contacts the inboard end face of the inner ring and these are arranged in the axial direction.

[0012] In the above-described wheel bearing device, it is preferable that the pitch circle diameter of the second rolling element row is larger than the pitch circle diameter of the first rolling element row. By increasing the pitch circle diameter of the second rolling element row in this way, the outer diameter of the inner ring is increased, making it easier to secure space on the inner circumference of the inner ring for contact with the cylindrical portion of the outer coupling member. The pitch circle diameter of the rolling element row is the diameter of the circle connecting the centers of the multiple rolling elements that make up the rolling element row.

[0013] In the above-described wheel bearing device, the contact portion between the cylindrical portion of the outer coupling member and the inner ring can be provided within the axial range of the second inner raceway surface.

[0014] In the above-described wheel bearing device, the spline fitting portion (the fitting portion between the male spline portion and the female spline portion) between the outer coupling member and the hub ring is provided on the outer circumference of the hub ring. Therefore, the diameter of the spline fitting portion is larger compared to the conventional product shown in Figure 3, in which the spline fitting portion is provided on the inner circumference of the hub ring. This allows for a reduction in the axial dimension of the spline fitting portion while maintaining its strength. For example, the entire spline fitting portion can be provided on the inner circumference of the inner ring. In this case, the inboard end of the hub ring can be provided on the inner circumference of the inner ring, thereby reducing the axial dimension of the hub ring.

[0015] The above-described wheel bearing device has an inner peripheral surface of the inner ring that includes a large-diameter inner peripheral surface provided at the inboard-side end, a small-diameter inner peripheral surface provided on the outboard side of the large-diameter inner peripheral surface and fitted to the inner ring fitting surface of the hub ring, and a shoulder surface connecting the large-diameter inner peripheral surface and the small-diameter inner peripheral surface. The cylindrical portion of the outer joint member can be configured to abut against the shoulder surface from the inboard side. The outboard-side end of the cylindrical portion and the shoulder surface of the inner ring can have an arbitrary shape, such as a plane perpendicular to the central axis or a tapered surface having a constant angle.

[0016] The above-described wheel bearing device has a screw tightening structure that generates an axial force in the direction of bringing the hub ring and the outer joint member closer to each other to fix them, and can be configured such that the hub ring and the outer joint member do not abut in the axial direction. In this case, the preload applied to the wheel bearing can be adjusted by the tightening force of the screw tightening structure.

Effects of the Invention

[0017] As described above, according to the present invention, in a wheel bearing device in which the outer peripheral surface of the hub ring and the inner peripheral surface of the outer joint member are spline-fitted, the axial dimension can be shortened to achieve weight reduction.

Brief Description of the Drawings

[0018] [Figure 1] It is an axial cross-sectional view of a wheel bearing device. [Figure 2] It is an enlarged view of FIG. 1. [Figure 3] It is an axial cross-sectional view of a conventional wheel bearing device. [Figure 4] It is an axial cross-sectional view of another conventional wheel bearing device.

Embodiments for Carrying Out the Invention

[0019] Hereinafter, embodiments of the present invention will be described based on the drawings.

[0020] A wheel bearing device 1 according to an embodiment of the present invention includes, as shown in FIG. 1, a wheel bearing 10 and a constant velocity universal joint 20.

[0021] The wheel bearing 10 includes, as main component members, an outer ring 11 as an outer member, an inner member 12, a plurality of balls 15, and a cage 16. Seal members 17 and 18 are provided at both axial ends of an annular space defined between the outer ring 11 and the inner member 12.

[0022] The outer ring 11 integrally has a cylindrical portion 11c and a flange 11d for vehicle body attachment that extends radially outward from the outer peripheral surface of the cylindrical portion 11c. On the inner peripheral surface of the cylindrical portion 11c, a first outer raceway surface 11a and a second outer raceway surface 11b having an arcuate cross-section are formed at an axial interval. In the flange 11d for vehicle body attachment, a plurality of bolt mounting holes 11e penetrating this in the axial direction are formed at circumferential intervals. The outer ring 11 is attached to the vehicle body using bolt members attached to the respective bolt mounting holes 11e.

[0023] The inner member 12 has a hub ring 13 and an inner ring 14.

[0024] The hub ring 13 integrally has a substantially cylindrical tubular portion 13a and a flange 13b for wheel attachment that extends radially outward from the outer peripheral surface of the tubular portion 13a. On the outer peripheral surface of the tubular portion 13a, a first inner raceway surface 12a having an arcuate cross-section facing the first outer raceway surface 11a of the outer ring 11 and an inner ring fitting surface 13c having a cylindrical surface shape are formed. The flange 13b for wheel attachment is provided on the outboard side (left side in the figure) of the first inner raceway surface 12a, and the inner ring fitting surface 13c is provided on the inboard side (right side in the figure) of the first inner raceway surface 12a. In the flange 13b for wheel attachment, a plurality of bolt mounting holes 13d penetrating this in the axial direction are formed at circumferential intervals. The hub ring 13 is attached to the wheel using bolt members attached to the respective bolt mounting holes 13d.

[0025] The outer circumferential surface of the inner ring 14 has a second inner raceway surface 12b with a circular arc cross-section that faces the second outer raceway surface 11b of the outer ring 11. The inner circumferential surface of the inner ring 14 has a large-diameter inner circumferential surface 14b provided at the inboard end, a small-diameter inner circumferential surface 14c provided on the outboard side of the large-diameter inner circumferential surface 14b, and a shoulder surface 14d connecting the large-diameter inner circumferential surface 14b and the small-diameter inner circumferential surface 14c. The small-diameter inner circumferential surface 14c of the inner ring 14 is fitted into the inner ring fitting surface 13c of the hub ring 13, and in this embodiment, it is press-fitted. The shoulder surface 14d of the inner ring 14 is a plane perpendicular to the central axis.

[0026] A first rolling element row B1, consisting of multiple balls 15, is provided between the first outer raceway surface 11a of the outer ring 11 and the first inner raceway surface 12a of the inner member 12 (hub ring 13). A second rolling element row B2, consisting of multiple balls 15, is provided between the second outer raceway surface 11b of the outer ring 11 and the second inner raceway surface 12b of the inner member 12 (inner ring 14). In the illustrated example, the pitch circle diameter of the balls 15 in the second rolling element row B2 is larger than the pitch circle diameter of the balls 15 in the first rolling element row B1. The balls 15 of each rolling element row B1 and B2 are held at equal intervals in the circumferential direction by a retainer 16.

[0027] The constant velocity universal joint 20 is a fixed constant velocity universal joint provided at the outboard end of the drive shaft. The constant velocity universal joint 20 comprises an outer joint member 21, an inner joint member 22 arranged on the inner circumference of the outer joint member 21, a plurality of balls 23 as torque transmission members, and a cage 24 that holds the plurality of balls 23. The outer joint member 21 has a mouth portion 26 with a plurality of track grooves 25 formed on its inner circumferential surface. The inner joint member 22 has a plurality of track grooves 27 formed on its outer circumferential surface and a through hole 28 formed in the axial center. The outboard end of the intermediate shaft 30 is inserted into the through hole 28 of the inner joint member 22, and these are coupled in a torque-transmitting manner by spline fitting. One ball 23 is placed between the track grooves 25 of the outer joint member 21 and the track grooves 27 of the inner joint member 22. The cage 24 has multiple pockets 29 formed at equal intervals in the circumferential direction, and one ball 23 is contained in each pocket 29.

[0028] The outer joint member 21 has a cylindrical portion 31 that protrudes from the mouth portion 26 toward the outboard side. The cylindrical portion 31 is cylindrical in shape and has a female spline portion Sf formed on its inner circumferential surface (see Figure 2). A male spline portion Sm is formed on the outer circumferential surface of the inboard side end of the cylindrical portion 13a of the hub wheel 13. Torque can be transmitted between the two members by fitting the male spline portion Sm of the hub wheel 13 with the female spline portion Sf of the cylindrical portion 31 of the outer joint member 21. The outer circumferential surface of the cylindrical portion 31 is fitted with the large-diameter inner circumferential surface 14b of the inner ring 14 with a radial gap in between. The outboard side end 31a of the cylindrical portion 31 abuts against the shoulder surface 14d of the inner ring 14 from the inboard side. In the illustrated example, both the outboard side end 31a of the cylindrical portion 31 and the shoulder surface 14d of the inner ring 14 are planes perpendicular to the axial direction.

[0029] The above-described wheel bearing device 1 is assembled by the following procedure. First, a single unit comprising multiple balls 15 and a cage 16 is mounted on the first and second outer raceway surfaces 11a and 11b of the outer ring 11, respectively. Then, the cylindrical portion 13a of the hub ring 13 is inserted into the inner circumference of the outer ring 11 from the outboard side, and the balls 15 of the first rolling element row B1 are sandwiched between the first outer raceway surface 11a of the outer ring 11 and the first inner raceway surface 12a of the hub ring 13. After that, the inner ring 14 is press-fitted into the inner ring fitting surface 13c of the hub ring 13 from the inboard side.

[0030] Subsequently, the outer joint member 21 of the constant velocity universal joint 20 is brought closer to the hub wheel 13 from the inboard side, and the outer circumferential surface of the cylindrical portion 31 of the outer joint member 21 is fitted onto the large-diameter inner circumferential surface 14b of the inner ring 14. Then, the outer joint member 21 is moved further towards the inboard side, and while fitting the female spline portion Sf formed on the inner circumferential surface of the cylindrical portion 31 of the outer joint member 21 with the male spline portion Sm formed on the outer circumferential surface of the hub wheel 13, the outboard end 31a of the cylindrical portion 31 is brought into contact with the shoulder surface 14d of the inner ring 14 (see Figure 2). In this state, the bolt member 40 is inserted into the inner circumference of the hub wheel 13 from the outboard side, and the male threaded portion 41 provided on the inboard end of the bolt member 40 is screwed into the female threaded portion 32 of the mouth portion 26 and tightened (see Figure 1). This generates an axial force that brings the hub wheel 13 and the outer joint member 21 closer together, fixing them in a state where torque can be transmitted between them.

[0031] In the assembled state of the wheel bearing device 1, the outboard end of the cylindrical portion 31 of the outer coupling member 21 abuts against the shoulder surface 14d of the inner ring 14, but the hub ring 13 and the outer coupling member 21 do not abut in the axial direction (see Figure 2). That is, an axial gap G is provided between the inboard end of the hub ring 13 and the outer coupling member 21. This allows the preload applied to both rolling element rows B1 and B2 of the wheel bearing 10 to be adjusted by adjusting the tightening force of the bolt member 40.

[0032] In the wheel bearing device 1 described above, the contact portion P between the cylindrical portion 31 of the outer coupling member 21 and the inner ring 14 is located on the inner circumference of the inner ring 14, that is, on the outboard side of the inboard end face 14a of the inner ring 14. In the illustrated example, the contact portion P is located within the axial range of the second inner raceway surface 12a. As a result, at least a part of the cylindrical portion 31 is positioned on the inner circumference of the inner ring 14, making it possible to shorten the axial dimension of the wheel bearing device 1 and reduce its weight compared to the conventional product shown in Figure 4, where the cylindrical portion 223 is in contact with the inboard end face of the inner ring 207 and they are arranged in the axial direction.

[0033] In this embodiment, as shown in Figure 1, the pitch circle diameter of the balls 15 of the second rolling element row on the inboard side is larger than the pitch circle diameter of the balls 15 of the first rolling element row on the outboard side. Therefore, the second inner raceway surface 12b of the inner ring 14 is positioned on the outer diameter side of the first inner raceway surface 12a of the hub ring 13. As a result, the outer circumferential surface of the inner ring 14 is enlarged, and space can be secured on the inner circumference of the inner ring 14 for providing a contact portion P. In the illustrated example, an annular recess is formed on the inner diameter side of the inboard end face 14a of the inner ring 14, and the cylindrical portion 31 of the outer joint member 21 is inserted into this recess from the inboard side, so that the outboard end portion 31a of the cylindrical portion 31 abuts against the bottom surface (shoulder surface 14d) of the recess of the inner ring 14.

[0034] Furthermore, by providing a spline fitting portion S on the outer circumference of the hub ring 13, the diameter of the spline fitting portion S can be increased compared to the conventional product shown in Figure 3, where the spline fitting portion was provided on the inner circumference of the hub ring. This allows for a reduction in axial length while maintaining the strength (allowable torque) of the spline fitting portion S. In the illustrated example, the axial dimension of the spline fitting portion S is shorter than the axial dimension of the inner ring 14, and the entire axial area of ​​the spline fitting portion S is located on the inner circumference of the inner ring 14. This allows the inboard end of the hub ring 13 to be located on the inner circumference of the inner ring 14, thereby shortening the axial dimension of the hub ring 13 and reducing the weight of the wheel bearing device 1.

[0035] Furthermore, in the wheel bearing device 1 described above, the contact portion P between the cylindrical portion 31 of the outer joint member 21 and the inner ring 14 and the spline fitting portion S between the cylindrical portion 31 of the outer joint member 21 and the hub ring 13 are adjacent to each other. Since the rotational relative displacement between the outer joint member 21 and the hub ring 13 is substantially zero at the spline fitting portion S, by positioning the contact portion P adjacent to this spline fitting portion S, the rotational relative displacement between the cylindrical portion 31 of the outer joint member 21 and the shoulder surface 14d of the inner ring 14 at the contact portion P can be suppressed, thereby suppressing the generation of stick-slip noise.

[0036] The present invention is not limited to the embodiments described above. Other embodiments of the present invention will be described below, but redundant explanations of points similar to those described above will be omitted.

[0037] For example, the above embodiment shows a case where the first inner raceway surface 12a is directly formed on the hub ring 13, but it is not limited to this. For example, the inner ring on which the first inner raceway surface 12a is formed may be formed separately from the hub ring, and this inner ring may be fitted onto the outer circumferential surface of the hub ring. Also, the above embodiment shows a case where the outer ring 11 integrally has a cylindrical portion 11c on which the first and second outer raceway surfaces 11a and 11b are formed, and a flange 11d for mounting to the vehicle body, but it is not limited to this. The cylindrical portion 11c and the flange 11d may be formed separately.

[0038] Furthermore, the screw fastening structure for fixing the hub wheel 13 and the outer joint member 21 is not limited to the above. For example, the outer joint member 21 may be provided with a stem portion extending from the mouth portion 26 to the outboard side, and the screw fastening structure may be formed by this stem portion and a nut screwed onto its outboard end.

[0039] Furthermore, the rolling elements provided in the wheel bearing device 1 are not limited to balls, but may also be rollers (for example, tapered rollers). [Explanation of Symbols]

[0040] 1. Wheel bearing device 10 Wheel bearings 11. Outer ring (outer member) 11a First outer raceway surface 11b Second outer raceway surface 12 Inner member 12a 1st inner raceway surface 12b 2nd inner raceway surface 13 Hub Wheel 13c Inner ring mating surface 14 Inner circle 14a Inboard end face 14b Large diameter inner surface 14c Small diameter inner surface 14d shoulder surface 15. Ball (rolling element) 20. Constant velocity universal joint 21 Outer joint member 31 Cylindrical part 40 Bolt Members B1 1st rolling element row B2 Second Rolling Element Row P Contact part S spline fitting section Sf Female spline section Sm Male spline section

Claims

1. A wheel bearing comprising: an outer member having first and second outer raceway surfaces formed on its inner circumferential surface; an inner member having first and second inner raceway surfaces formed on its outer circumferential surface; a first rolling element row consisting of a plurality of rolling elements rotatably disposed between the first outer raceway surface and the first inner raceway surface; and a second rolling element row consisting of a plurality of rolling elements rotatably disposed between the second outer raceway surface and the second inner raceway surface; A wheel bearing device comprising a constant velocity universal joint having an outer joint member fixed to the inner member, The inner member comprises an inner ring having the second inner raceway surface formed on its outer circumferential surface, and a hub ring having an inner ring fitting surface into which the inner circumferential surface of the inner ring fits, and a male spline portion formed on its outer circumferential surface. The outer joint member has a cylindrical portion on its inner circumferential surface which has a female spline portion that fits with the male spline portion. The outboard end of the cylindrical portion of the outer joint member abuts against the inner ring from the inboard side. A wheel bearing device in which the contact portion between the cylindrical portion of the outer joint member and the inner ring is provided on the inner circumference of the inner ring.

2. The wheel bearing device according to claim 1, wherein the pitch circle diameter of the second rolling element row is larger than the pitch circle diameter of the first rolling element row.

3. The wheel bearing device according to claim 1, wherein the contact portion between the cylindrical portion of the outer joint member and the inner ring is provided within the axial range of the second inner raceway surface.

4. The wheel bearing device according to claim 1, wherein the entire area of ​​the fitting portion between the male spline portion and the female spline portion is provided on the inner circumference of the inner ring.

5. The wheel bearing device according to claim 4, wherein the inboard end of the hub ring is provided on the inner circumference of the inner ring.

6. The inner circumferential surface of the inner ring has a large-diameter inner circumferential surface provided at the inboard end, a small-diameter inner circumferential surface provided on the outboard side of the large-diameter inner circumferential surface and fitted to the inner ring fitting surface of the hub ring, and a shoulder surface connecting the large-diameter inner circumferential surface and the small-diameter inner circumferential surface. The wheel bearing device according to claim 1, wherein the cylindrical portion of the outer joint member abuts against the shoulder surface from the inboard side.

7. The wheel bearing device according to claim 6, wherein the outboard end of the cylindrical portion and the shoulder surface of the inner ring are planes perpendicular to the central axis.

8. The screw fastening structure has a mechanism that generates an axial force in a direction that brings the hub wheel and the outer joint member closer together to fix them in place. The wheel bearing device according to claim 1, wherein the hub ring and the outer joint member are not in contact in the axial direction.

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