Wheel bearing device

Abstract

The present invention provides a wheel bearing device in which the amount of preload applied can be changed according to the magnitude of the applied torque. [Solution] In the wheel bearing device 1, the inner ring side spline 412a formed on the inner end face 41 of the inner ring 4 and the coupling side spline 262a formed on the outer end face 262 of the mouth portion 26 are spline-fitted, and the inner end face 41 of the inner ring 4 on which the inner ring side spline 412a is formed and the outer end face 262 of the mouth portion 26 on which the coupling side spline 262a is formed are inclined with respect to a direction perpendicular to the axial direction.

Description

Technical Field

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

Background Art

[0002] Conventionally, there is known a wheel bearing device that rotatably supports a wheel in a suspension device of a vehicle such as an automobile like a passenger car and an SUV. A torque transmissionable connection is achieved between a hub ring, which is an inner member, and a constant velocity joint shaft portion inserted into the inner diameter portion of the hub ring by spline fitting. The constant velocity joint includes an outer joint member, an inner joint member, balls incorporated between the outer joint member and the inner joint member, and a retainer for holding the balls. The shaft portion that is spline-fitted to the hub ring is provided on the outer joint member.

[0003] In such a wheel bearing device, the axial end face of the hub ring and the axial end face of the mouth portion of the outer joint member are in contact. When a driving force is input to the outer joint member, relative slippage may occur between the hub ring and the outer joint member, generating abnormal noise such as a clicking sound.

[0004] Therefore, in order to suppress relative slippage occurring between the hub ring and the outer joint member and prevent the generation of abnormal noise, a wheel bearing device has been devised in which the axial end face of the hub ring and the axial end face of the mouth portion of the outer joint member are spline-fitted (see Patent Document 1).

[0005] At the other axial end of the hub ring in the wheel bearing device described in Patent Document 1, a caulking portion caulked to an inner ring fitted to the hub ring is formed. A hub ring side spline formed in the caulking portion of the hub ring and a joint side spline formed in the mouth portion of the outer joint member are spline-fitted.

[0006] Furthermore, in wheel bearing devices, it is preferable to reduce friction in the bearing device and improve fuel efficiency by setting a small preload applied to the bearing device during straight-line driving when the torque applied to the bearing device is small. On the other hand, it is preferable to set a large preload applied to the bearing device to increase its rigidity during acceleration of a vehicle when a large torque is applied to the bearing device, and during deceleration when reverse torque transmission occurs, such as in regenerative braking of an electric vehicle. [Prior art documents] [Patent Documents]

[0007] [Patent Document 1] Patent No. 5556509 [Overview of the Initiative] [Problems that the invention aims to solve]

[0008] However, since the preload applied to the wheel bearing device described in Patent Document 1 is constant, if the preload is increased to, for example, increase the rigidity of the bearing device, the friction of the bearing device increases, leading to a problem of decreased vehicle fuel efficiency. Conversely, if the preload applied to the bearing device is set low in order to improve fuel efficiency, it may become difficult to accommodate electric vehicles and other vehicles with large vehicle weights and motor torques.

[0009] This invention has been made in view of the above circumstances, and provides a wheel bearing device in which the amount of preload applied can be changed according to the magnitude of the applied torque. [Means for solving the problem]

[0010] In other words, the wheel bearing device comprises an outer member having double rows of outer raceway surfaces on its inner circumference, an inner member consisting of a hub ring having an inner raceway surface on one axial side opposite to the outer raceway surface on one axial side, and an inner ring fitted to the hub ring having an inner raceway surface on the other axial side opposite to the outer raceway surface on the other axial side, a double row of rolling elements rotatably housed between the two raceway surfaces of the outer member and the inner member, and an outer coupling member having a mouth portion that is rotatably connected to a shaft, wherein an inner ring side spline formed on the other axial end face of the inner ring and a coupling side spline formed on the axial end face of the mouth portion are spline-fitted, and the other axial end face of the inner ring where the inner ring side spline is formed and the axial end face of the mouth portion where the coupling side spline is formed are inclined with respect to a direction perpendicular to the axial direction. [Effects of the Invention]

[0011] According to the present invention, the amount of preload applied to the wheel bearing device can be changed according to the amount of torque applied to the wheel bearing device, making it possible to achieve both improved fuel efficiency of the vehicle and increased rigidity of the wheel bearing device. [Brief explanation of the drawing]

[0012] [Figure 1] This is a side cross-sectional view showing a wheel bearing device. [Figure 2] This is a side cross-sectional view showing the hardened section of the inner ring. [Figure 3] This is a side cross-sectional view showing the positional relationship between the contact point with the ball on the inner raceway surface of the inner ring and the spline on the inner ring side. [Figure 4] This is a side cross-sectional view showing the auxiliary spline fitting portion according to the first embodiment. [Figure 5] This is a side cross-sectional view showing the auxiliary spline fitting portion according to the second embodiment. [Figure 6] This is a side cross-sectional view showing the auxiliary spline fitting portion according to the third embodiment. [Figure 7]It is a side cross-sectional view showing an auxiliary spline fitting portion according to the fourth embodiment.

Mode for Carrying Out the Invention

[0013] Hereinafter, embodiments for carrying out the present invention will be described with reference to the accompanying drawings.

[0014] [Wheel Bearing Device] The wheel bearing device 1 shown in FIG. 1 is an embodiment of the wheel bearing device according to the present invention, and rotatably supports a wheel in a suspension device of a vehicle such as an automobile.

[0015] In the following description, the axial direction represents the direction along the rotation axis X of the wheel bearing device 1, the radial direction represents the direction orthogonal to the rotation axis X of the wheel bearing device 1, and the circumferential direction represents the direction along an arc centered on the rotation axis X of the wheel bearing device 1. Further, the outer side represents the wheel side of the wheel bearing device 1 when attached to the vehicle body on one side in the axial direction, and the inner side represents the vehicle body side of the wheel bearing device 1 when attached to the vehicle body on the other side in the axial direction.

[0016] The wheel bearing device 1 includes 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 side ball rows 5 and outer side ball rows 6 which are rolling element rows, an outer side seal member 9, an inner side seal member 10, and an outer joint member 21 of a constant velocity joint 20.

[0017] An inner side opening 2a into which the inner side seal member 10 can be fitted is formed at the inner side end portion of the outer ring 2. An outer side opening 2b into which the outer side seal member 9 can be fitted is formed at the outer side end portion of the outer ring 2.

[0018] When the inner side seal member 10 is fitted into the inner side opening 2a, the opening end on the inner side of the annular space S formed by the outer ring 2 and the inner member is blocked. When the outer side seal member 9 is fitted into the outer side opening 2b, the opening end on the outer side of the annular space S is blocked.

[0019] On the inner peripheral surface of the outer ring 2, an inner side outer track surface 2c and an outer side outer track surface 2d are formed. On the outer peripheral surface of the outer ring 2, a vehicle body mounting flange 2e for attaching the outer ring 2 to a vehicle body side member (knuckle) is integrally formed.

[0020] On the inner side end portion of the outer peripheral surface of the hub ring 3, a small diameter step portion 3a having a smaller diameter than the outer side end portion is formed. On the outer side end portion of the small diameter step portion 3a in the hub ring 3, a shoulder portion 31 is formed.

[0021] The small diameter step portion 3a in the hub ring 3 has an inner side end surface 3h at the inner side end portion. The inner side end surface 3h faces the inner side. The inner side end surface 3h has a first end surface 3ha parallel to the radial direction and a second end surface 3hb located on the inner diameter side of the first end surface 3ha and inclined with respect to the radial direction (see FIG. 3).

[0022] On the outer side end portion of the hub ring 3, a wheel mounting flange 3b for attaching a wheel is integrally formed. The wheel mounting flange 3b is provided with bolt holes 3f into which hub bolts are press-fitted or wheel bolts are screwed. The wheel mounting flange 3b has a flange surface 3j against which a brake rotor assembled to the wheel mounting flange 3b abuts.

[0023] On the hub ring 3, an outer side inner track surface 3c is formed so as to face the outer side outer track surface 2d of the outer ring 2. Further, in the hub ring 3, a lip sliding surface 3d with which the outer side seal member 9 slidably contacts is formed on the base side of the wheel mounting flange 3b.

[0024] A through hole 3e is formed in the inner diameter portion of the hub wheel 3, extending axially. The through hole 3e penetrates the hub wheel 3 in the axial direction. The through hole 3e is an example of a recess in the hub wheel.

[0025] An inner ring 4 is provided on the small-diameter stepped portion 3a of the hub wheel 3. The inner ring 4 is made of a medium-carbon structural steel such as S53C or S55C. The inner ring 4 is fixed to the small-diameter stepped portion 3a of the hub wheel 3 by press-fitting. The inner ring 4 applies preload to the rolling rows, which are the inner ball row 5 and the outer ball row 6.

[0026] The inner ring 4 has an inner end face 41 at its inner end and an outer end face 42 at its outer end. The inner end face 41 is an example of an axial end face on the other side. The outer end face 42 is an example of an axial end face on the one side. The inner end face 41 faces the inner side in the axial direction. The outer end face 42 faces the outer side in the axial direction. The outer end face 42 faces the shoulder portion 31 of the hub ring 3 in the axial direction. The inner ring 4 also has a fitting surface 43 that fits into the small diameter stepped portion 3a of the hub ring 3.

[0027] The inner end face 41 has a vertical surface 411 aligned with the radial direction perpendicular to the axial direction, and an inclined surface 412 that is inclined with respect to the radial direction, which is perpendicular to the axial direction. The inclined surface 412 is located on the inner diameter side of the vertical surface 411. The inclined surface 412 is inclined toward the inner side as it moves from the inner diameter side toward the outer diameter side in the radial direction. An inner ring side spline 412a is formed on the inclined surface 412 of the inner end face 41.

[0028] The outer circumferential surface of the inner ring 4 is provided with an inner raceway surface 4a that faces the outer raceway surface 2c on the inner side of the outer ring 2. In other words, the inner raceway surface 4a is formed on the inner side of the inner member by the inner ring 4.

[0029] 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 retainer 8.

[0030] The inner ball row 5 is rotatably sandwiched between the inner raceway surface 4a of the inner ring 4 and the outer raceway surface 2c on the inner side of the outer ring 2. The outer ball row 6 is rotatably sandwiched between the inner raceway surface 3c of the hub ring 3 and the outer raceway surface 2d on the outer side of the outer ring 2.

[0031] In other words, the inner ball row 5 and the outer ball row 6 are rotatably housed between the raceway surfaces of the outer and inner members. The inner ring 4 applies preload to the rolling rows, the inner ball row 5 and the outer ball row 6.

[0032] In the wheel bearing device 1, a double-row angular contact ball bearing is constructed from an outer ring 2, a hub ring 3 and an inner ring 4, an inner ball row 5, and an outer ball row 6. Alternatively, the wheel bearing device 1 may be configured with a double-row tapered roller bearing instead of the double-row angular contact ball bearing.

[0033] The constant velocity universal joint 20 comprises an outer joint member 21 having a track groove 25 formed on its inner circumferential surface, an inner joint member 22 having a track groove 22a formed on its outer circumferential surface opposite to the track groove 25, a ball 23 incorporated between the track groove 25 and the track groove 22a, and a cage 24 interposed between the inner circumferential surface of the outer joint member 21 and the outer circumferential surface of the inner joint member 22 to hold the ball 23. The cage 24 is a retainer for holding the ball 23.

[0034] The outer joint member 21 has a mouth portion 26 that houses the internal components consisting of the inner joint member 22, the ball 23, and the cage 24, and a shaft portion 27 that protrudes from the mouth portion 26 toward the outer side in the axial direction. The track groove 25 is formed on the inner circumferential surface of the mouth portion 26.

[0035] The shaft end of the shaft 50, which receives driving force from a drive source such as an engine or motor, is press-fitted into the inner coupling member 22. The inner coupling member 22 and the shaft 50 are connected in a manner that allows for torque transmission by spline fitting.

[0036] The mouth portion 26 of the outer joint member 21 supports the shaft 50 so that it can rotate around the rotation axis X via the inner joint member 22, the ball 23, and the cage 24. In other words, the mouth portion 26 is rotationally connected to the shaft 50. The shaft 50 is rotatable around the rotation center P in the mouth portion 26.

[0037] The mouse portion 26 has an outer peripheral surface 261 and an outer end surface 262 located on the outer side of the outer peripheral surface 261. The outer end surface 262 is located at the outer end of the mouse portion 26 and faces outwards. The outer end surface 262 is an example of an axial end surface of the mouse portion.

[0038] The outer end face 262 is an inclined surface that slopes with respect to the radial direction, which is perpendicular to the axial direction. The outer end face 262 slopes inward from the inner diameter side to the outer diameter side in the radial direction. A joint-side spline 262a is formed on the outer end face 262.

[0039] The inclination angle of the inclined surface 412 on the inner end face 41, where the inner ring spline 412a is formed, and the inclination angle of the outer end face 262, where the joint-side spline 262a is formed, are formed at the same angle.

[0040] The inner ring spline 412a formed on the inclined surface 412 of the inner end face 41 of the inner ring 4 and the coupling side spline 262a formed on the outer end face 262 of the mouth portion 26 are spline-fitted. The spline-fitting of the inner ring spline 412a and the coupling side spline 262a configures the hub ring 3 and the inner ring 4 and the outer coupling member 21 to rotate integrally.

[0041] The shaft portion 27 of the outer joint member 21 is inserted into the through hole 3e of the hub wheel 3 from the inner side. The shaft portion 27 has a female threaded portion 27a formed on its outer end face extending toward the inner side. With the shaft portion 27 inserted into the through hole 3e of the hub wheel 3, the hub wheel 3 and the outer joint member 21 are fastened together by screwing a bolt 30, which has been inserted into the through hole 3e from the outer side, into the female threaded portion 27a of the shaft portion 27. In this way, the hub wheel 3 and the inner ring 4 are connected to the outer joint member 21.

[0042] The bolt 30 is inserted into the through hole 3e of the hub wheel 3 from the outer side, and the head 30a of the bolt 30 engages with the stepped surface 3g formed at the outer end of the through hole 3e. The bolt 30 has a male threaded portion 30b at its inner end, and the male threaded portion 30b is screwed into the female threaded portion 27a of the shaft portion 27.

[0043] In the wheel bearing device 1, when assembling the outer joint member 21 of the constant velocity universal joint 20 with the hub wheel 3, the shaft portion 27 is inserted into the through hole 3e of the hub wheel 3 from the inner side, and then the male threaded portion 30b of the bolt 30 is screwed into the female threaded portion 27a of the shaft portion 27, thereby pulling the shaft portion 27 to the outer side of the through hole 3e, thereby completing the fastening of the hub wheel 3 and the outer joint member 21.

[0044] When the shaft portion 27 is inserted into the through hole 3e and the male threaded portion 30b of the bolt 30 is screwed into the female threaded portion 27a of the shaft portion 27, the inner ring side spline 412a and the coupling side spline 262a are spline-fitted, and the mouth portion 26 is pressed towards the outer side. By pressing the mouth portion 26 towards the outer side, preload can be applied to the inner ball row 5 and the outer ball row 6 inside the wheel bearing device 1.

[0045] Furthermore, the outer diameter of the shaft portion 27 is smaller than the inner diameter of the through hole 3e into which the shaft portion 27 is inserted, and a gap is formed between the inner circumferential surface of the through hole 3e and the outer circumferential surface of the shaft portion 27. In other words, the through hole 3e of the hub wheel 3 and the shaft portion 27 inserted into the through hole 3e do not come into contact with each other. Therefore, it is possible to suppress creep and the generation of abnormal noise between the hub wheel 3 and the shaft portion 27 of the outer joint member 21.

[0046] Furthermore, in the wheel bearing device 1, the inner ring side spline 412a of the inner ring 4 and the joint side spline 262a of the outer joint member 21 are not in surface contact but are spline-fitted, which makes it possible to suppress the generation of abnormal noises such as clicking sounds between the inner ring 4 and the outer joint member 21.

[0047] Furthermore, in the wheel bearing device 1, the inner ring side spline 412a of the inner ring 4 and the joint side spline 262a of the outer joint member 21 are spline-fitted, and the inner end of the hub ring 3 does not have a crimped portion that is crimped to the inner ring 4. Therefore, compared to the case where a crimped portion is formed on the inner end of the hub ring 3 and the crimped portion is spline-fitted to the outer joint member 21, the cost of crimping the hub ring 3 can be reduced.

[0048] Furthermore, the wheel bearing device 1 is subjected to large torques during vehicle acceleration and during deceleration when reverse torque transmission occurs, such as in regenerative braking in electric vehicles.

[0049] In the wheel bearing device 1, the inclined surface 412 of the inner end face 41 on which the inner ring spline 412a is formed, and the outer end face 262 on which the coupling side spline 262a is formed, are inclined in a direction that expands in diameter toward the inner side. When a large torque is applied to the wheel bearing device 1, a separation force acts between the inner ring 4 and the outer coupling member 21, and an expanding force, which is a force in the direction of expanding the diameter, is applied to the inner ring 4.

[0050] The expansion force applied to the inner ring 4 increases the preload on the inner ball row 5 and the outer ball row 6 provided by the inner ring 4, thereby improving the rigidity of the wheel bearing device 1.

[0051] Therefore, by setting a small preload to the wheel bearing device 1 in its natural state where no large torque is acting, it is possible to reduce friction in the wheel bearing device 1 during straight-line driving of the vehicle, etc., when no large torque is acting, thereby improving the vehicle's fuel efficiency.

[0052] On the other hand, when a large torque is applied to the wheel bearing device 1 during acceleration or deceleration of the vehicle, an expanding force is applied to the inner ring 4, increasing the preload, and thus improving the rigidity of the wheel bearing device 1.

[0053] Thus, in the wheel bearing device 1, the amount of preload applied changes according to the magnitude of the applied torque, making it possible to achieve both improved fuel efficiency for the vehicle and increased rigidity of the wheel bearing device 1.

[0054] The wheel bearing device 1 includes a spline seal 15 that covers the outer circumference of the spline fitting portion between the inner ring side spline 412a and the coupling side spline 262a. The spline seal is fitted to the outer circumferential surface of the inner ring 4 and extends from the inner ring 4 toward the inner side. The inner end of the spline seal is in contact with the outer circumferential surface 261 of the mouth portion 26.

[0055] [Inner ring hardened section] As shown in Figure 2, in the inner ring 4, the inner raceway surface 4a, the inclined surface 412 of the inner end face 4b on which the inner ring side spline 412a is formed, the outer end face 42, and the portion from the mating surface 43 to a predetermined depth are configured as a hardened treatment area Q. The inner raceway surface 4a, the inclined surface 412 of the inner end face 4b on which the inner ring side spline 412a is formed, the outer end face 42, and the mating surface 43 are hardened surfaces that have undergone a hardening treatment.

[0056] The inner ring 4 can be hardened, for example, by high-frequency induction hardening. By hardening the inner ring 4, the hardness of the hardened surface can be increased.

[0057] Furthermore, by performing high-frequency induction hardening on the inner raceway surface 4a, inclined surface 412, outer end surface 42, and mating surface 43 of the inner ring 4, which is made of medium-carbon structural steel, it is possible to perform hardening at a lower cost compared to performing a full hardening treatment on the inner ring 4, which is made of high-carbon chromium bearing steel such as SUJ2.

[0058] Here, the joint-side spline 262a and the inner ring-side spline 412a are spline-fitted, but if the inclined surface 412 on which the inner ring-side spline 412a is formed is an unhardened portion that has not undergone heat treatment, it is difficult to sufficiently increase the durability of the spline-fitted portion between the joint-side spline 262a and the inner ring-side spline 412a.

[0059] However, in this embodiment, the inclined surface 412 of the inner ring 4 is a hardened surface that has undergone heat treatment, so the hardness of the inclined surface 412 including the inner ring side spline 412a is increased, and it is possible to sufficiently improve the durability of the spline fitting portion between the joint side spline 262a and the inner ring side spline 412a.

[0060] [Relationship between the pitch circle diameter of the inner ball and the pitch circle diameter of the outer ball] The pitch circle diameter of the balls 7 constituting the inner ball row 5 is Di, and the pitch circle diameter of the balls 7 constituting the outer ball row 6 is Do.

[0061] The inner pitch circle diameter Di is the diameter of the circle centered on the rotation axis X and passing through the center Ci of ball 7 in the inner ball row 5. The outer pitch circle diameter Do is the diameter of the circle centered on the rotation axis X and passing through the center Co of ball 7 in the outer ball row 6. The inner pitch circle diameter Di is larger than the outer pitch circle diameter Do (Di > Do).

[0062] The inner pitch circle diameter Di is an example of the pitch circle diameter of the rolling element on the other axial side, and the outer pitch circle diameter Do is an example of the pitch circle diameter of the rolling element on one axial side.

[0063] By making the inner pitch circle diameter Di larger than the outer pitch circle diameter Do, the spline fitting portion between the coupling side spline 262a and the inner ring side spline 412a can be positioned on the outer side, compared to the case where the inner pitch circle diameter Di and the outer pitch circle diameter Do are formed to be the same size, and the wheel bearing device 1 can be formed in a large diameter and narrow width shape.

[0064] This makes it possible to construct a large-diameter, lightweight wheel bearing device 1 that can accommodate electric vehicles, which tend to have increased vehicle weight due to the battery installation and higher motor torque.

[0065] [Positional relationship between the contact point with the ball on the inner raceway surface of the inner ring and the spline on the inner ring side] As shown in Figure 3, the balls 7 of the inner ball row 5 are in contact with the inner raceway surface 4a of the inner ring 4 at the contact point 44, and the contact angle of the balls 7 in the inner ball row 5 with respect to the inner raceway surface 4a is α. The contact angle α is the angle of inclination of the straight line L connecting the center Ci of the ball 7 in the inner ball row 5 and the contact point 44 with respect to the radial direction.

[0066] The contact point 44 between the inner raceway surface 4a of the inner ring 4 and the ball 7 can be configured to be located on the inner side of the outer end of the inner ring spline 412a in the axial direction. In other words, the contact point 44 can be configured to be located in a position that overlaps with the inner ring spline 412a when viewed from the radial direction.

[0067] By arranging the contact points 44 in this manner, the axial length of the inner ring 4 on which the inner ring side spline 412a is formed can be reduced, making it possible to narrow the width of the wheel bearing device 1.

[0068] Furthermore, the contact point 44 between the inner raceway surface 4a of the inner ring 4 and the ball 7 can be configured to be located radially on the outer diameter side of the outer diameter end of the inner ring side spline 412a. By positioning the contact point 44 on the outer diameter side of the inner ring side spline 412a, it is possible to increase the diameter of the wheel bearing device 1 and improve the rigidity of the wheel bearing device 1.

[0069] [First embodiment of auxiliary spline fitting portion] The wheel bearing device 1 can also be configured to include an auxiliary spline fitting portion in addition to the spline fitting portion between the coupling-side spline 262a and the inner ring-side spline 412a, where the hub ring 3 and the outer coupling member 21 are spline fitted together.

[0070] In the wheel bearing device 1A shown in Figure 4, a coupling-side auxiliary spline 271 is formed on the outer circumferential surface of the shaft portion 27 of the outer coupling member 21, and a hub wheel-side auxiliary spline 32 is formed on the inner circumferential surface of the through hole 3e of the hub wheel 3. The coupling-side auxiliary spline 271 and the hub wheel-side auxiliary spline 32 are spline-fitted.

[0071] The outer circumferential surface of the shaft portion 27 on which the joint-side auxiliary spline 271 is formed, and the inner circumferential surface of the through hole 3e on which the hub wheel-side auxiliary spline 32 is formed, are surfaces parallel to the axial direction.

[0072] In this way, by providing an auxiliary spline fitting portion between the joint-side auxiliary spline 271 and the hub-wheel-side auxiliary spline 32, in addition to the spline fitting portion between the joint-side spline 262a and the inner-ring-side spline 412a, the hub-wheel 3 and inner-ring 4 and the outer joint member 21 can be connected more firmly, thereby improving the rigidity of the wheel bearing device 1A and the durability of the spline fitting portion in the wheel bearing device 1A.

[0073] [Second embodiment of auxiliary spline fitting portion] In addition to the spline fitting portion between the joint-side spline 262a and the inner ring-side spline 412a, if an auxiliary spline fitting portion is provided where the hub ring 3 and the outer joint member 21 are spline fitted, the wheel bearing device can also be configured as shown in Figure 5, as in the wheel bearing device 1B.

[0074] In the wheel bearing device 1B shown in Figure 5, a coupling-side auxiliary spline 272 is formed on the outer end face of the shaft portion 27 of the outer coupling member 21, and a hub wheel-side auxiliary spline 33 is formed on the inner circumferential surface of the through hole 3e of the hub wheel 3. The coupling-side auxiliary spline 272 and the hub wheel-side auxiliary spline 33 are spline-fitted.

[0075] The outer end face of the shaft portion 27 on which the joint-side auxiliary spline 272 is formed, and the inner circumferential surface of the through hole 3e on which the hub wheel-side auxiliary spline 33 is formed, are inclined surfaces that are inclined with respect to the radial direction perpendicular to the axial direction.

[0076] In this way, by providing an auxiliary spline fitting portion between the joint-side auxiliary spline 272 and the hub-wheel-side auxiliary spline 33, in addition to the spline fitting portion between the joint-side spline 262a and the inner ring-side spline 412a, the hub wheel 3 and inner ring 4 and the outer joint member 21 can be connected more firmly, thereby improving the rigidity of the wheel bearing device 1B and the durability of the spline fitting portion in the wheel bearing device 1B.

[0077] [Third embodiment of the auxiliary spline fitting portion] In addition to the spline fitting portion between the joint-side spline 262a and the inner ring-side spline 412a, if an auxiliary spline fitting portion is provided where the hub ring 3 and the outer joint member 21 are spline fitted, the wheel bearing device 1C shown in Figure 6 can also be configured.

[0078] In the wheel bearing device 1C shown in Figure 6, a joint-side auxiliary spline 262b is formed on the outer end face 262 of the mouse portion 26 of the outer joint member 21, and a hub wheel-side auxiliary spline 34 is formed on the second end face 3hb of the inner end face 3h of the hub wheel 3. The joint-side auxiliary spline 262b and the hub wheel-side auxiliary spline 34 are spline-fitted.

[0079] On the outer end face 262 of the mouth portion 26, the joint-side auxiliary spline 262b is located on the inner diameter side of the joint-side spline 262a. In this embodiment, the joint-side spline 262a and the joint-side auxiliary spline 262b are formed continuously.

[0080] The outer end face 262 of the mouth portion 26 on which the joint-side auxiliary spline 262b is formed, and the second end face 3hb of the inner end face 3h of the hub wheel 3 on which the hub wheel-side auxiliary spline 34 is formed, are inclined surfaces that are inclined with respect to the radial direction perpendicular to the axial direction.

[0081] In this way, by providing an auxiliary spline fitting portion between the joint-side auxiliary spline 262b and the hub-wheel-side auxiliary spline 34, in addition to the spline fitting portion between the joint-side spline 262a and the inner-ring-side spline 412a, the hub-wheel 3 and inner-ring 4 and the outer joint member 21 can be connected more firmly, thereby improving the rigidity of the wheel bearing device 1C and the durability of the spline fitting portion in the wheel bearing device 1C.

[0082] [Fourth embodiment of the auxiliary spline fitting portion] The wheel bearing device 1 can also be configured to include an auxiliary spline fitting portion in which the hub ring 3 and the inner ring 4 are spline fitted, in addition to the spline fitting portion between the coupling-side spline 262a and the inner ring-side spline 412a.

[0083] In the wheel bearing device 1D shown in Figure 7, a hub-side auxiliary spline 311 is formed on the shoulder portion 31 of the hub ring 3, and an inner-ring side auxiliary spline 421 is formed on the outer end face 42 of the inner ring 4. The hub-side auxiliary spline 311 and the inner-ring side auxiliary spline 421 are spline-fitted.

[0084] The shoulder portion 31 of the hub ring 3, on which the auxiliary spline 311 on the hub ring side is formed, and the outer end face 42 of the inner ring 4, on which the auxiliary spline 421 on the inner ring side is formed, are surfaces parallel to the radial direction.

[0085] In this way, by providing an auxiliary spline fitting portion between the hub wheel auxiliary spline 311 and the inner ring auxiliary spline 421, in addition to the spline fitting portion between the joint-side spline 262a and the inner ring-side spline 412a, the hub wheel 3 and the inner ring 4 can be connected more firmly, thereby improving the rigidity of the wheel bearing device 1D and the durability of the spline fitting portion in the wheel bearing device 1D.

[0086] In this embodiment, the hub wheel 3 is provided with a through hole 3e that penetrates axially. However, instead of the through hole 3e, it is also possible to have a recess that is recessed from the outer side to the inner side, with the outer end closed. In this case, the shaft portion 27 of the outer joint member 21 can be inserted into the recess of the hub wheel.

[0087] 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. [Explanation of Symbols]

[0088] 1, 1A, 1B, 1C, 1D Wheel bearing device 2 Outer ring 2c (Inner side) outer raceway surface 2d (Outer side) outer raceway surface 3 Hub wheels 3a Small diameter stepped section 3c (Outer side) Inner raceway surface 3e Through hole 3h Inner side end face 3hb 2nd end face 4. Inner Ring 4a (Inner side) Inner raceway surface 5. Inner ball row 6 Outer ball row 20. Constant velocity universal joint 21 Outer joint member 26 Mouse section 27 Shaft section 31 Shoulder 32, 33, 34 Hub wheel-side auxiliary splines 41 Inner side end face 42 Outer end face 44 contact points 262 Outer end face 262a Spline on the joint side 271, 272, 262b Joint-side auxiliary splines 311 Hub wheel-side auxiliary spline 412 Slope 412a Inner ring spline 421 Inner ring auxiliary spline Di (the diameter of the pitch circle of the balls in the inner ball row) Do (the diameter of the pitch circle of the balls in the outer ball row)

Claims

1. An outer member having double rows of outer raceway surfaces on its inner circumference, An inner member comprising a hub ring having an inner raceway surface on one axial side that is opposite to the outer raceway surface on one axial side, and an inner ring fitted to the hub ring having an inner raceway surface on the other axial side that is opposite to the outer raceway surface on the other axial side, A double row of rolling elements is rotatably housed between the raceway surfaces of the outer member and the inner member, A wheel bearing device comprising an outer coupling member having a mouth portion that is rotatably connected to a shaft, The inner ring side spline formed on the axial end face of the inner ring and the joint side spline formed on the axial end face of the mouse portion are spline-fitted. A wheel bearing device in which the axial end face of the inner ring on which the inner ring side splines are formed, and the axial end face of the mouse portion on which the coupling side splines are formed, are inclined with respect to a direction perpendicular to the axial direction.

2. The outer joint member has a shaft portion that protrudes axially from the mouse portion and is inserted into the recess of the hub wheel. The wheel bearing device according to claim 1, wherein a joint-side auxiliary spline formed on the outer circumferential surface of the shaft portion and a hub-wheel-side auxiliary spline formed on the inner circumferential surface of the recess are spline-fitted.

3. The outer joint member has a shaft portion that protrudes axially from the mouse portion and is inserted into the recess of the hub wheel. The joint-side auxiliary spline formed on one axial end face of the shaft portion and the hub-wheel-side auxiliary spline formed on the inner circumferential surface of the recess are spline-fitted. The wheel bearing device according to claim 1, wherein the axial end face of the shaft portion on which the joint-side auxiliary spline is formed, and the inner circumferential surface of the recess on which the hub wheel-side auxiliary spline is formed are inclined with respect to a direction perpendicular to the axial direction.

4. The hub wheel-side auxiliary spline formed on the axial end face of the hub wheel and the joint-side auxiliary spline formed on the axial end face of the mouse portion are spline-fitted. The wheel bearing device according to claim 1, wherein the axial end face of the hub wheel on which the hub wheel side auxiliary spline is formed, and the axial end face of the mouse portion on which the joint side auxiliary spline is formed are inclined with respect to a direction perpendicular to the axial direction.

5. The hub wheel has a small-diameter stepped portion into which the inner ring is fitted, and a shoulder portion located at one axial end of the small-diameter stepped portion and facing the axial end face of the inner ring in the axial direction. The wheel bearing device according to claim 1, wherein the hub ring side auxiliary spline formed on the shoulder portion of the hub ring and the inner ring side auxiliary spline formed on the axial end face of the inner ring are spline-fitted.

6. The inner ring is formed of medium-carbon structural steel. The inner raceway surface of the inner ring and the axial end face on the other side of the inner ring, on which the splines are formed, are hardened surfaces that have undergone a heat treatment process. A wheel bearing device according to any one of claims 1 to 5.

7. A wheel bearing device according to any one of claims 1 to 5, wherein the pitch circle diameter of the rolling element on the other axial side is larger than the pitch circle diameter of the rolling element on the one axial side.

8. The wheel bearing device according to any one of claims 1 to 5, wherein the contact point between the rolling element and the inner raceway surface of the inner ring is located axially on the other side of the axial end of the inner ring side spline.

9. The wheel bearing device according to any one of claims 1 to 5, wherein the contact point between the rolling element and the inner raceway surface of the inner ring is located on the outer diameter side of the outer diameter end of the inner ring side spline.

10. The outer joint member has a shaft portion that protrudes axially from the mouse portion and is inserted into the recess of the hub wheel. The aforementioned recess is a through hole that penetrates the hub wheel in the axial direction. A wheel bearing device according to any one of claims 1 to 5, wherein the hub ring and the outer joint member are fastened together by a bolt inserted into the through hole.

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