Wheel bearing device

Abstract

To provide a wheel bearing device which can be reduced in size and weight, and can suppress the generation of noise and a creep when a drive force is inputted therein.SOLUTION: A wheel bearing device 1 comprises: an outer ring 2 having outside raceway surfaces 2c, 2d; an inner member composed of a hub ring 3 having a penetration hole 3e penetrating in an axial direction and formed with an inside raceway surface 3c opposing the outside raceway surface 2d, a constant velocity universal joint 20 having a mouth part 26 connected to a shaft 50 and formed with an inside raceway surface 263a opposing the outside raceway surface 2c, and a stem part 27 inserted into the penetration hole 3e of the hub ring 3; and an inner-side ball row 5 and an outer-side ball row 6 which are accommodated between both the raceway surfaces of the outer ring 2 and the inner member. In the wheel bearing device 1, a pitch circle diameter Di of the inner-side ball row 5 is larger than a pitch circle diameter Do of the outer-side ball row 6, and an outer-side end face 262 of the mouth part 26 and an inner-side end face 31 of the hub ring 3 are spline-fit to each other.SELECTED DRAWING: Figure 2

Description

[Technical field]

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

[0002] Conventionally, as disclosed in Patent Document 1, a wheel bearing device that rotatably supports wheels in the suspension of vehicles such as automobiles such as passenger cars and SUVs, and that has a constant velocity universal joint that is connected to a hub wheel, which is an inner member, so as to be able to transmit torque, has been known.

[0003] In the wheel bearing device described in Patent Document 1, the inner raceway surface of the inner ring is located on the outer diameter side of the mouth part of the constant velocity universal joint, and the distance between the flange surface of the hub ring and the center of rotation of the mouth part of the constant velocity universal joint relative to the shaft is reduced, thereby narrowing the wheel bearing device in the axial direction. The hub ring and the inner ring are fitted together, and the inner ring and the constant velocity universal joint are in surface contact in the axial direction. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] International Publication No. 2021 / 148675 Summary of the Invention [Problem to be solved by the invention]

[0005] In the wheel bearing device having the configuration disclosed in Patent Document 1, the inner raceway surface formed on the inner ring is located on the outer diameter side of the mouth part of the constant velocity universal joint, so that the size and weight of the wheel bearing device increase, and the configuration goes against the weight reduction that contributes to reducing fuel consumption. In particular, since the inner ring is located on the outer diameter side of the mouth part in the radial direction, the outer diameter of the outer ring is large.

[0006] In addition, when driving force from the engine or motor is input to the constant velocity universal joint, relative slippage can occur between the inner ring and the constant velocity universal joint, which are in surface contact with each other, resulting in abnormal noises such as clicking sounds, or creep can occur between the hub wheel and inner ring, which are fitted together.

[0007] The present invention has been made in consideration of the above-mentioned circumstances, and provides a wheel bearing device that is compact and lightweight, and can suppress the occurrence of abnormal noise and creep when driving force is input. [Means for solving the problem]

[0008] That is, the wheel bearing device comprises an inner member consisting of an outer member having a double row outer raceway surface on its inner circumference, a hub wheel having a through hole penetrating in the axial direction in its inner diameter portion and having an inner raceway surface on one axial side opposed to the outer raceway surface on one axial side, a mouth portion connected to the shaft so as to be able to transmit rotation and having an inner raceway surface on the other axial side opposed to the outer raceway surface on the other axial side, and a constant velocity joint extending axially from the mouth portion and having a stem portion inserted into the through hole of the hub wheel, and double row rolling elements accommodated so as to roll freely between both raceway surfaces of the outer member and the inner member, wherein the pitch circle diameter of the rolling elements on the other axial side is larger than the pitch circle diameter of the rolling elements on the one axial side, and the one axial end face of the mouse portion and the other axial end face of the hub wheel are spline fitted together. Effect of the Invention

[0009] According to the present invention, it is possible to reduce the size and weight of a wheel bearing device, and to suppress the occurrence of abnormal noise and creep when a driving force is input. [Brief description of the drawings]

[0010] [Figure 1] 1 is a side cross-sectional view showing a wheel bearing device. [Diagram 2] 4 is an enlarged side cross-sectional view showing a connection structure between a hub wheel and a constant velocity universal joint. FIG. [Diagram 3]1A is a view of the inner end face of the hub wheel as viewed from the inner side, and FIG. 1B is a view of the outer end face of the mouth portion as viewed from the outer side. [Figure 4] FIG. 6 is a side cross-sectional view showing a wheel bearing device according to a second embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] Hereinafter, an embodiment of the present invention will be described with reference to the accompanying drawings.

[0012] [Wheel bearing device] A wheel bearing device 1 shown in FIG. 1 is one embodiment of a wheel bearing device according to the present invention, and supports a wheel rotatably in a suspension system of a vehicle such as an automobile.

[0013] In the following description, the axial direction refers to the direction along the rotation axis X of the wheel support bearing device 1. The outer side refers to one side in the axial direction, which is the wheel side of the wheel support bearing device 1 when attached to the vehicle body, and the inner side refers to the other side in the axial direction, which is the vehicle body side of the wheel support bearing device 1 when attached to the vehicle body.

[0014] The wheel bearing device 1 includes an outer ring 2 as an outer member, a hub wheel 3 as an inner member, a constant velocity universal joint 20, two rolling rows of an inner side ball row 5 and an outer side ball row 6, an outer side seal member 9, and an inner side seal member 10.

[0015] An inner side opening 2a is formed at the inner side end of the outer ring 2, into which an inner side seal member 10 can be fitted. An outer side opening 2b is formed at the outer side end of the outer ring 2, into which an outer side seal member 9 can be fitted.

[0016] The inner seal member 10 is fitted into the inner opening 2a to close the inner opening end of the annular space S formed by the outer ring 2 and the inner member. The outer seal member 9 is fitted into the outer opening 2b to close the outer opening end of the annular space S.

[0017] An inner-side outer raceway surface 2c and an outer-side outer raceway surface 2d are formed on the inner peripheral surface of the outer ring 2. A vehicle body mounting flange 2e for mounting the outer ring 2 to a vehicle body side member (knuckle) is integrally formed on the outer peripheral surface of the outer ring 2.

[0018] A wheel mounting flange 3b for mounting a wheel is integrally formed on the outer end of the hub wheel 3. The wheel mounting flange 3b is provided with bolt holes 3f into which hub bolts are press-fitted or into which 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.

[0019] The hub ring 3 is formed with an outer-side inner raceway surface 3c so as to face the outer-side outer raceway surface 2d of the outer ring 2. The hub ring 3 also is formed with a lip sliding surface 3d on the base side of the wheel mounting flange 3b, with which the outer-side seal member 9 comes into sliding contact.

[0020] A through hole 3e is formed in the inner diameter portion of the hub wheel 3 along the axial direction, and into which the constant velocity universal joint 20 is inserted. The through hole 3e passes through the hub wheel 3 in the axial direction.

[0021] The constant velocity universal joint 20 includes 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 facing the track groove 25 formed on its outer circumferential surface, balls 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 balls 23.

[0022] The outer joint member 21 has a mouth portion 26 that houses internal components consisting of the inner joint member 22, the ball 23, and the cage 24, and a stem portion 27 that extends integrally from the mouth portion 26 toward the outer side in the axial direction. The track grooves 25 are formed on the inner circumferential surface of the mouth portion 26.

[0023] An axial end of a shaft 50, to which driving force is input from a driving source such as an engine or a motor, is press-fitted into the inner joint member 22. The inner joint member 22 and the shaft 50 are connected by spline fitting to be able to transmit torque.

[0024] The mouth part 26 of the outer joint member 21 supports the shaft 50 rotatably about the rotation axis X via the inner joint member 22, the ball 23, and the cage 24. In other words, the mouth part 26 is connected to the shaft 50 so as to be capable of transmitting rotation. The shaft 50 is rotatable about a rotation center P of the mouth part 26.

[0025] Mouth portion 26 has an outer peripheral surface 261, an outer end face 262 located on the outer side of outer peripheral surface 261, and a tapered surface 263 located in the axial direction between outer end face 262 and outer peripheral surface 261. Outer end face 262 is an example of one axial end face of the mouth portion.

[0026] An inner seal member 10 is fitted onto the outer peripheral surface 261 of the mouth portion 26. The inner seal member 10 is located between the inner end of the outer ring 2 and the outer peripheral surface 261 of the mouth portion 26. An inner inner raceway surface 263a is formed on the tapered surface 263 of the mouth portion 26 so as to face the inner outer raceway surface 2c of the outer ring 2.

[0027] The inner ball row 5 and the outer ball row 6, which are rolling rows, are configured by a plurality of balls 7, which are rolling elements, being held by a cage 8.

[0028] The inner ball row 5 is rollably sandwiched between the inner outer raceway surface 2c of the outer ring 2 and the inner raceway surface 263a of the mouth portion 26. The outer ball row 6 is rollably sandwiched between the outer outer raceway surface 2d of the outer ring 2 and the inner raceway surface 3c of the hub ring 3. The mouth portion 26 applies a preload to the inner ball row 5 and outer ball row 6, which are the rolling rows.

[0029] In the wheel bearing device 1, a double-row angular ball bearing is formed by the outer ring 2, the hub ring 3, the constant velocity universal joint 20, the inner ball row 5, and the outer ball row 6. The wheel bearing device 1 may be formed by a double-row tapered roller bearing.

[0030] [Connection structure between hub wheel and constant velocity joint] 1 and 2, the outer joint member 21 has an outer-side end face 262 that is a surface perpendicular to the axial direction and faces the outer side. In other words, the angle of the outer-side end face 262 with respect to the axial direction is 90°. The outer-side end face 262 is located at the outer-side end of the mouth portion 26.

[0031] The hub wheel 3 has an inner side end face 31 at its inner side end. The inner side end face 31 is an example of an end face on the other axial side of the hub wheel. The inner side end face 31 is a surface perpendicular to the axial direction and faces the inner side. In other words, the angle of the inner side end face 31 with respect to the axial direction is 90°.

[0032] As shown in Fig. 3(a), a plurality of convex teeth 31a are formed along the circumferential direction on the inner end face 31 of the hub wheel 3. As shown in Fig. 3(b), a plurality of concave grooves 262a are formed along the circumferential direction on the outer end face 262 of the mouth portion 26. The convex teeth 31a of the inner end face 31 and the concave grooves 262a of the outer end face 262 are spline-fitted.

[0033] In other words, the inner end face 31 of the hub wheel 3 and the outer end face 262 of the mouth portion 26 are spline-fitted, and the spline-fitting of the inner end face 31 and the outer end face 262 allows the hub wheel 3 and the constant velocity joint 20 to rotate integrally.

[0034] In this embodiment, convex teeth 31a are formed on the inner end face 31 of the hub wheel 3, and concave grooves 262a are formed on the outer end face 262 of the mouth portion 26, but it is also possible to have a configuration in which concave grooves are formed on the inner end face 31 of the hub wheel 3, and convex teeth are formed on the outer end face 262 of the mouth portion 26.

[0035] The stem portion 27 of the outer joint member 21 is inserted into the through hole 3e of the hub wheel 3. A male thread portion 27a is formed on the outer end of the stem portion 27, and by screwing a nut 30 onto the male thread portion 27a, the hub wheel 3 and the constant velocity universal joint 20 are fastened together with the stem portion 27 inserted into the through hole 3e.

[0036] With the stem portion 27 inserted into the through hole 3e and the nut 30 screwed onto the male thread portion 27a, the inner end face 31 of the hub wheel 3 and the outer end face 262 of the mouth portion 26 are spline-fitted together, and the mouth portion 26 is pressed toward the outer side. By pressing the mouth portion 26 toward the outer side, a preload can be applied to the inner ball row 5 and the outer ball row 6 inside the wheel bearing device 1.

[0037] In addition, the stem portion 27 is inserted into the through hole 3e, and the inner end face 31 of the hub wheel 3 and the outer end face 262 of the mouth portion 26 are spline-engaged, and then the nut 30 is screwed onto the male threaded portion 27a, thereby connecting the hub wheel 3 and the constant velocity universal joint 20.

[0038] The inner diameter of through hole 3e in hub wheel 3 is R1, and the outer diameter of stem portion 27 in constant velocity joint 20 is R2. The outer diameter R2 of stem portion 27 is formed smaller than the inner diameter R1 of through hole 3e, and a gap G is formed between the inner circumferential surface of through hole 3e in hub wheel 3 and the outer circumferential surface of stem portion 27.

[0039] In other words, the through hole 3e of the hub wheel 3 and the stem portion 27 inserted into the through hole 3e are not fitted together and are not in contact with each other. Therefore, in the wheel bearing device 1, spline fitting is only formed between the inner end face 31 of the hub wheel 3 and the outer end face 262 of the mouth portion 26.

[0040] In this way, a gap G is formed between the inner surface of the through hole 3e in the hub wheel 3 and the outer surface of the stem portion 27, making it possible to prevent creep from occurring between the hub wheel 3 and the stem portion 27 of the constant velocity universal joint 20, and to prevent abnormal noise from occurring.

[0041] In addition, since the inner side end face 31 of the hub wheel 3 and the outer side end face 262 of the mouth portion 26 of the constant velocity universal joint 20 are spline fitted rather than being in surface contact, the generation of abnormal noises such as clicking sounds between the hub wheel 3 and the constant velocity universal joint 20 can be suppressed.

[0042] [Relationship between the pitch circle diameter of the inner ball and the pitch circle diameter of the outer ball] The balls 7 constituting the inner ball row 5 have a pitch circle diameter Di, and the balls 7 constituting the outer ball row 6 have a pitch circle diameter Do.

[0043] The inner-side pitch circle diameter Di is the diameter of a circle that is centered on the rotation axis X and passes through the centers Ci of the balls 7 in the inner-side ball row 5. The outer-side pitch circle diameter Do is the diameter of a circle that is centered on the rotation axis X and passes through the centers Co of the balls 7 in the outer-side ball row 6. The inner-side pitch circle diameter Di is larger than the outer-side pitch circle diameter Do (Di>Do).

[0044] 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.

[0045] The pitch circle diameter Di on the inner side is larger than the pitch circle diameter Do on the outer side, but since the wheel bearing device 1 does not have an inner ring and the inner side inner raceway surface 263a is formed in the mouth portion 26 of the constant velocity universal joint 20, it is possible to reduce the outer diameter of the outer ring 2 by the amount that an inner ring does not exist between the outer ring 2 and the mouth portion 26. This makes it possible to reduce the size and weight of the wheel bearing device 1.

[0046] In addition, by making the inner pitch circle diameter Di larger than the outer pitch circle diameter Do and by spline-fitting the inner end face 31 of the hub wheel 3 and the outer end face 262 of the mouth portion 26, it is possible to make the wheel bearing device 1 smaller and lighter, and to suppress the occurrence of abnormal noise and creep when driving force is input from the drive source.

[0047] [Relationship between pitch circle diameter of inner ball and pitch between balls] The balls 7 constituting the inner ball row 5 and the balls 7 constituting the outer ball row 6 are arranged at a ball-to-ball pitch a in the axial direction. The ball-to-ball pitch a is the distance in the axial direction between the center Ci of a ball 7 in the inner ball row 5 and the center Co of a ball 7 in the outer ball row 6.

[0048] In the wheel bearing device 1, the ratio (Di / a) of the inner pitch circle diameter Di to the ball pitch a is set to be 2.0 or more. In other words, the pitch circle diameter Di and the ball pitch a are set to satisfy the relationship (Di / a) ≧ 2.0.

[0049] By setting the pitch circle diameter Di and the ball pitch a such that (Di / a) ≧ 2.0, when the inner pitch circle diameter Di is larger than the outer pitch circle diameter Do, it is possible to reduce the axial size of the wheel bearing device 1. This makes it possible to reduce the weight of the wheel bearing device 1.

[0050] [Second embodiment of wheel bearing device] The wheel bearing device 1 can also be configured as a wheel bearing device 1A shown in Fig. 4. The wheel bearing device 1A differs from the wheel bearing device 1 in that it includes a hub wheel 3A instead of the hub wheel 3, and a constant velocity universal joint 20A instead of the constant velocity universal joint 20. The other configurations of the wheel bearing device 1A are the same as those of the wheel bearing device 1.

[0051] The hub wheel 3A differs from the hub wheel 3 in that it has an inner side end surface 31A instead of the inner side end surface 31. The rest of the configuration of the hub wheel 3A is the same as that of the hub wheel 3.

[0052] The inner end surface 31A is located at the inner end of the hub wheel 3A and faces the inner side. The inner end surface 31A is an example of the other axial end surface of the hub wheel.

[0053] The inner end surface 31A is an inclined surface that is inclined in a direction perpendicular to the axial direction. The inner end surface 31A is inclined toward the inner side from the inner diameter side to the outer diameter side in the radial direction. A plurality of convex teeth 31Aa are formed on the inner end surface 31A along the circumferential direction.

[0054] The constant velocity universal joint 20A differs from the constant velocity universal joint 20 in that it includes an outer joint member 21A having a mouth portion 26A instead of the outer joint member 21 having the mouth portion 26. The other configurations of the constant velocity universal joint 20A and the outer joint member 21A are similar to those of the constant velocity universal joint 20 and the outer joint member 21, respectively.

[0055] Mouth portion 26A differs from mouth portion 26 in that it has outer end surface 262A instead of outer end surface 262. Other configurations of mouth portion 26A are similar to those of mouth portion 26.

[0056] The outer end surface 262A is located at the outer end of the mouth portion 26A and faces the outer side. The outer end surface 262A is an example of one axial end surface of the mouth portion.

[0057] The outer end surface 262A is an inclined surface that is inclined in a direction perpendicular to the axial direction. The outer end surface 262A is inclined toward the inner side from the inner diameter side to the outer diameter side in the radial direction. A plurality of recessed grooves 262Aa are formed in the outer end surface 262A along the circumferential direction.

[0058] The convex teeth 31Aa on the inner end face 31A of the hub wheel 3A and the concave grooves 262Aa on the outer end face 262A of the mouth portion 26A are spline-fitted.

[0059] In other words, the inner end face 31A of the hub wheel 3A and the outer end face 262A of the mouth portion 26A are spline-fitted, and the spline-fitting of the inner end face 31A and the outer end face 262A allows the hub wheel 3A and the constant velocity joint 20A to rotate integrally.

[0060] The stem portion 27 of the constant velocity universal joint 20A is inserted into the through hole 3e of the hub wheel 3A, and the inner end face 31A of the hub wheel 3A and the outer end face 262A of the mouth portion 26A are spline-engaged. Then, the nut 30 is screwed onto the male threaded portion 27a, thereby connecting the hub wheel 3A and the constant velocity universal joint 20A.

[0061] In this embodiment, convex teeth 31Aa are formed on the inner end face 31A of the hub wheel 3A and concave grooves 262Aa are formed on the outer end face 262A of the mouth portion 26A, but it is also possible to have a configuration in which concave grooves are formed on the inner end face 31A of the hub wheel 3A and convex teeth are formed on the outer end face 262A of the mouth portion 26A.

[0062] In the wheel bearing device 1A, the outer side end face 262A and the inner side end face 31A, which are spline-fitted to each other, are inclined with respect to a direction perpendicular to the axial direction, so that it is possible to increase the fitting area between the outer side end face 262A and the inner side end face 31A compared to when the outer side end face 262 and the inner side end face 31, which are surfaces perpendicular to the axial direction, are spline-fitted.

[0063] By increasing the mating area between the outer side end surface 262A and the inner side end surface 31A, the contact surface pressure between the outer side end surface 262A and the inner side end surface 31A can be reduced, and it is possible to prevent a large load from being applied to the mating portion between the outer side end surface 262A and the inner side end surface 31A, which would cause damage to the outer side end surface 262A and the inner side end surface 31A.

[0064] In addition, by inclining the outer side end face 262A and the inner side end face 31A in a direction perpendicular to the axial direction, fiber flow becomes easier when forging the hub wheel 3A and the constant velocity universal joint 20A, making it possible to perform forging easily.

[0065] Furthermore, outer end surface 262A of mouth portion 26A is inclined toward the inner side from the inner diameter side toward the outer diameter side, so that the angle between the outer peripheral surface of stem portion 27 and outer end surface 262A becomes larger. This makes it possible to suppress the stress applied to stem portion 27 and mouth portion 26A from concentrating at the boundary between stem portion 27 and mouth portion 26A.

[0066] The inclination angle of outer end surface 262A of mouth portion 26A relative to a direction perpendicular to the axial direction is the same as the inclination angle of inner end surface 31A of hub wheel 3A relative to a direction perpendicular to the axial direction.

[0067] The angles θ of the outer end surface 262A and the inner end surface 31A with respect to the axial direction can be set to be equal to or greater than 45° and less than 90°.

[0068] By inclining the outer side end face 262A and the inner side end face 31A in a direction perpendicular to the axial direction, the contact surface pressure between the outer side end face 262A and the inner side end face 31A can be reduced. However, if the inclination angle of the outer side end face 262A and the inner side end face 31A in the direction perpendicular to the axial direction is too large, the axial length of the mating surface between the outer side end face 262A and the inner side end face 31A will become large, and the wheel bearing device 1A will become larger in size in the axial direction.

[0069] Therefore, by setting the angle θ of the outer side end face 262A and the inner side end face 31A with respect to the axial direction to be greater than or equal to 45° and less than 90°, it is possible to reduce the contact surface pressure between the outer side end face 262A and the inner side end face 31A while preventing the wheel bearing device 1A from increasing in size in the axial direction.

[0070] Although the embodiments of the present invention have been described above, the present invention is not limited to these embodiments, which are merely illustrative, and it goes without saying that the present invention can be embodied in various other forms without departing from the gist of the present invention. The scope of the present invention is indicated by the claims, and further includes the equivalent meanings set forth in the claims, and all modifications within the scope of the claims. [Explanation of symbols]

[0071] 1, 1A Wheel bearing device 2 Outer ring 2c (inner side) outer raceway 2d (Outer side) outer raceway 3. 3A Hub Wheel 3c (Outer) inner raceway 3e Through hole 5 Inner ball row 6 Outer ball row 20, 20A constant velocity universal joint 26, 26A Mouse section 27 Stem 31, 31A Inner end face 262, 262A Outer end face 263a (inner side) inner raceway Di Pitch circle diameter (of the balls in the inner ball row) Do Pitch circle diameter (of balls in the outer ball row)

Claims

1. an outer member having a double row outer raceway surface on an inner periphery thereof; an inner member comprising a hub wheel having an axially penetrating through hole in an inner diameter portion thereof and an inner raceway surface on one axial side opposed to the outer raceway surface on the one axial side; a mouth portion connected to a shaft so as to be capable of transmitting rotation therethrough and having an inner raceway surface on the other axial side opposed to the outer raceway surface on the other axial side; and a stem portion extending axially from the mouth portion and inserted into the through hole of the hub wheel; a double row of rolling elements rollably accommodated between the raceway surfaces of the outer member and the inner member; A wheel bearing device comprising: 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, a wheel bearing device according to claim 1, wherein one axial end face of said mouth portion and the other axial end face of said hub wheel are spline-fitted together.

2. 2. The wheel bearing device according to claim 1, wherein the axial end face of the mouth portion that is spline-fitted with the hub wheel and the other axial end face of the hub wheel that is spline-fitted with the mouth portion are inclined with respect to a direction perpendicular to the axial direction.

3. 3. The wheel bearing device according to claim 2, wherein an angle between the axial end face of the mouth portion that is spline-fitted with the hub wheel and the axial end face of the hub wheel that is spline-fitted with the mouth portion and the axial end face of the hub wheel that is spline-fitted with the mouth portion is greater than or equal to 45° and less than 90°.

4. 4. The wheel bearing device according to claim 1, wherein a gap is formed between an inner peripheral surface of the through hole in the hub wheel and an outer peripheral surface of the stem portion.

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