Wheel bearing device

Abstract

To provide a wheel bearing device which can suppress a stick slip at a contact part between a hub ring and a constant velocity free joint while maintaining a strength of a fastening part.SOLUTION: A wheel bearing device 1 includes: an outer member (outer ring 2) having outer raceway grooves 2c, 2d; an inner member composed of an inner ring 4 provided on a hub ring 3 and a small diameter stepped part 3a of the hub ring 3, and including a fastening part 3h formed on an inner-side end part of the small diameter stepped part 3a and including inner raceway grooves 3c, 4a in which the hub ring 3 and the inner ring 4 are integrally formed; a rolling element (ball 7) stored between the outer raceway grooves 2c, 2d and the inner raceway grooves 3c, 4a; and a constant velocity free joint 20 connected to the hub ring 3. The hub ring 3 includes a flat part 3i which is in contact with an outer-side end face of the shoulder part 23 of the constant velocity free joint 20. The flat part 3i projects on an inner side from the inner end part of the fastening part 3h, and is configured such that an outer diameter of the flat part 3i is positioned on a radially inner side from an inner diameter of the inner ring 4.SELECTED DRAWING: Figure 2

Description

[Technical field]

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

[0002] Conventionally, there is known a wheel bearing device for supporting a wheel rotatably in a suspension device of an automobile, etc. The wheel bearing device includes an outer member having double row outer raceway grooves on the inner circumference, a hub wheel having a small diameter step at the inner end of the outer circumference, and an inner ring provided on the small diameter step of the hub wheel, and the hub wheel and the inner ring are integrated by forming a crimped portion by crimping the inner end of the small diameter step of the hub wheel, an inner member having double row inner raceway grooves facing the double row outer raceway grooves, double row rolling elements accommodated in a rollable manner between the raceway grooves of the outer member and the inner member, and a constant velocity universal joint connected to the hub wheel.

[0003] The constant velocity universal joint is provided at one end of an intermediate shaft constituting a drive shaft, and includes an outer joint member, an inner joint member having a track groove formed on its outer circumferential surface facing the track groove of the outer joint member, and a ball inserted between the track groove of the outer joint member and the track groove of the inner joint member. The outer joint member of the constant velocity universal joint includes a shoulder portion forming the bottom of a cup-shaped mouth portion, and a shaft portion extending in the axial direction from the shoulder portion. The shaft portion of the outer joint member of the constant velocity universal joint is inserted into the shaft hole of the hub wheel, and the splines of the shaft portion of the outer joint member and the splines of the hub wheel are engaged. Furthermore, with the shoulder portion of the constant velocity universal joint butted against the crimped portion of the hub wheel, a fixing nut is fastened to the male thread of the shaft portion of the outer joint member with a predetermined tightening torque, so that torque from the drive shaft can be transmitted to the hub wheel via the outer joint member.

[0004] Here, in the wheel bearing device, the relative amount of slippage at the butting portion between the crimped portion of the hub wheel and the shoulder of the constant velocity universal joint may increase, causing stick-slip. To suppress such stick-slip, a wheel bearing device is known in which the crimped portion of the hub wheel is turned to form a flat surface, and the shoulder of the constant velocity universal joint is butted against the flat surface of the hub wheel. In this way, by butting the shoulder of the constant velocity universal joint against the flat surface of the hub wheel, the surface pressure at the butting portion between the crimped portion of the hub wheel and the shoulder of the constant velocity universal joint is reduced, suppressing stick-slip.

[0005] Furthermore, in a wheel bearing device in which a flat surface is formed at the crimped portion of the hub wheel, the flat surface is formed by turning the crimped portion after the crimped portion of the hub wheel is formed, which can make the manufacturing process complicated.To eliminate this complexity in the manufacturing process, a wheel bearing device is known in which the butt joint between the hub wheel and the shoulder portion of the constant velocity universal joint is positioned radially inward from the crimped portion of the hub wheel, and an axial gap is provided between the crimped portion of the hub wheel and the shoulder portion of the constant velocity universal joint (see Patent Document 1). [Prior art documents] [Patent documents]

[0006] [Patent Document 1] JP 2007-326451 A Summary of the Invention [Problem to be solved by the invention]

[0007] However, in the wheel bearing device of Patent Document 1, the butt joint between the hub wheel and the shoulder of the constant velocity universal joint is located radially inward of the crimped portion. In this way, the crimped portion of the hub wheel is made small to form a space for arranging a flat surface on the inner diameter side of the crimped portion, which may result in insufficient strength of the crimped portion. Depending on the design of the wheel bearing device, the structure of Patent Document 1 may not be applicable from the viewpoint of ensuring the strength of the crimped portion of the hub wheel. Furthermore, when a flat surface is provided at a position protruding from the inner end of the crimped portion toward the inner side to ensure the strength of the crimped portion of the hub wheel, if at least a part of the flat surface is located radially outward from the inner diameter of the inner wheel, the relative amount of slippage at the contact portion between the flat surface and the constant velocity universal joint becomes relatively large, and stick-slip may occur at the contact portion between the hub wheel and the constant velocity universal joint.

[0008] Therefore, an object of the present invention is to provide a wheel bearing device and a wheel support bearing device that can suppress the occurrence of stick-slip at the contact portion between the hub wheel and the constant velocity universal joint while maintaining the strength of the crimped portion. [Means for solving the problem]

[0009] That is, the present invention is made up of an outer member having double row outer raceway grooves on its inner circumference, a hub wheel having a small diameter step on its inner side end on its outer circumference, and an inner ring provided on the small diameter step of the hub wheel, and the hub wheel and the inner ring are integrated by crimping the inner side end of the small diameter step of the hub wheel to form a crimped portion, and an inner member having double row inner raceway grooves facing the double row outer raceway grooves, and a double row rolling bearing housed between the raceway grooves of the outer member and the inner member so as to be able to roll freely. A wheel bearing device comprising: a body, a shoulder portion and an axle portion extending axially from the shoulder portion, and a constant velocity universal joint which is connected to the hub wheel by inserting the axle portion into an axle hole of the hub wheel, wherein the hub wheel has a flat portion which abuts against an outer end face of the shoulder portion of the constant velocity universal joint, the flat portion of the hub wheel protruding toward the inner side from the inner end portion of the crimped portion, and the outer diameter of the flat portion is positioned radially inward relative to the inner diameter of the inner wheel. Effect of the Invention

[0010] The present invention has the following advantages.

[0011] That is, according to the present invention, it is possible to suppress the occurrence of stick-slip at the contact portion between the hub wheel and the constant velocity universal joint while maintaining the strength of the crimped portion. [Brief description of the drawings]

[0012] [Figure 1] 1 is a cross-sectional view showing a wheel bearing device according to an embodiment of the present invention; [Diagram 2] FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0013] Hereinafter, an embodiment of the present invention will be described with reference to the accompanying drawings.

[0014] 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.

[0015] The wheel bearing device 1 has a configuration referred to as the third generation, and includes an outer ring 2 as an outer member, a hub ring 3 and an inner ring 4 as inner members, two rolling rows consisting of an inner ball row 5 and an outer ball row 6, an inner seal member 9 and an outer seal member 10, and a constant velocity universal joint 20.

[0016] Here, the inner side refers to the vehicle body side of the wheel support bearing device 1 when it is attached to the vehicle body, and the outer side refers to the wheel side of the wheel support bearing device 1 when it is attached to the vehicle body. Also, the axial direction refers to the direction along the rotation axis X of the wheel support bearing device 1, with one axial end side being the outer side and the other axial end side being the inner side.

[0017] 1, an inner side opening 2a is formed at the inner side end of the outer ring 2, into which an inner side seal member 9 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 10 can be fitted. An inner side outer raceway groove 2c and an outer side outer raceway groove 2d are formed on the inner circumferential surface of the outer ring 2.

[0018] A vehicle body mounting flange 2e for mounting the outer ring 2 to a vehicle body member is integrally formed on the outer peripheral surface of the outer ring 2. The vehicle body mounting flange 2e is provided with bolt holes 2f into which fastening members (here, bolts) for fastening the outer ring 2 to the vehicle body member are inserted.

[0019] The inner end of the outer circumferential surface 3g of the hub wheel 3 is formed with a small diameter step 3a that is smaller in diameter than the outer end. A wheel mounting flange 3b for mounting a wheel is integrally formed with the outer end of the hub wheel 3. A plurality of bolt holes 3d are formed in the wheel mounting flange 3b. Hub bolts 3e for fastening the hub wheel 3 to a wheel or a brake component are press-fitted into the bolt holes 3d. The wheel mounting flange 3b is an example of a hub flange that extends radially outward. A spline for transmitting torque is formed on the inner circumferential surface of the shaft hole 3f of the hub wheel 3.

[0020] An outer side inner raceway groove 3c is provided on the outer peripheral surface 3g of the hub wheel 3 so as to face the outer side outer raceway groove 2d of the outer ring 2. In other words, the inner raceway groove 3c is formed by the hub wheel 3 on the outer side of the inner member. The outer side seal member 10 is fitted into the outer side opening end of the annular space formed by the outer ring 2 and the hub wheel 3, and closes the outer side opening end. The outer side seal member 10 is an example of a sealing device.

[0021] The inner ring 4 is provided on the small diameter step 3a of the hub ring 3. The inner ring 4 is press-fitted into the small diameter step 3a via a predetermined interference. Furthermore, the inner end of the small diameter step 3a of the hub ring 3 is crimped to plastically deform the hub ring 3 and the inner ring 4 to be integrated, preventing the inner ring 4 from slipping out of the hub ring 3 in the axial direction. The inner ring 4 applies preload to the inner ball row 5 and the outer ball row 6, which are rolling rows. The inner ring 4 has an inner side inner raceway groove 4a on the outer peripheral surface thereof so as to face the outer raceway groove 2c on the inner side of the outer ring 2. In other words, the inner ring 4 forms the inner raceway groove 4a on the inner side of the inner member.

[0022] The inner ball row 5 and the outer ball row 6, which are rolling rows, are formed by a plurality of balls 7, which are rolling bodies, being held by a cage 8. The inner ball row 5 is rollably sandwiched between the inner raceway groove 4a of the inner ring 4 and the outer raceway groove 2c on the inner side of the outer ring 2. The outer ball row 6 is rollably sandwiched between the inner raceway groove 3c of the hub ring 3 and the outer raceway groove 2d on the outer side of the outer ring 2. In other words, the inner ball row 5 and the outer ball row 6 are rollably accommodated between the raceway grooves of the outer member and the inner member. In the wheel bearing device 1, the outer ring 2, the hub ring 3 and the inner ring 4, the inner ball row 5, and the outer ball row 6 form a double-row angular ball bearing.

[0023] The constant velocity universal joint 20 is provided at one end of an intermediate shaft (not shown) that constitutes a drive shaft, and is connected to the hub wheel 3. The constant velocity universal joint 20 has an outer joint member 21, an inner joint member (not shown) having track grooves formed on its outer peripheral surface that face the track grooves of the outer joint member 21, and balls (not shown) assembled between the track grooves of the outer joint member 21 and the track grooves of the inner joint member.

[0024] The outer joint member 21 includes a shoulder portion 22 that forms the bottom of the cup-shaped mouth portion, and a shaft portion 23 that extends in the axial direction from the shoulder portion 22. The shoulder portion 22 and the shaft portion 23 of the outer joint member 21 are integrally formed. A spline is formed on the outer periphery of the shaft portion 23 of the outer joint member 21, and a male thread is formed at each end of the spline. The shaft portion 23 of the outer joint member 21 is inserted into the shaft hole 3f of the hub wheel 3, and the spline of the shaft portion 23 of the outer joint member 21 and the spline of the hub wheel 3 are engaged with each other. Furthermore, a fixing nut 11 is fastened to the male thread of the shaft portion 23 of the outer joint member 21 with a predetermined tightening torque, so that torque from the drive shaft can be transmitted to the hub wheel 3 via the outer joint member 21.

[0025] 1 or 2, the hub wheel 3 has a crimped portion 3h, a flat portion 3i, and a stepped portion 3j. The crimped portion 3h of the hub wheel 3 is formed by crimping the inner side end of the small diameter stepped portion 3a of the hub wheel 3.

[0026] The flat portion 3i of the hub ring 3 is formed on the inner diameter side portion of the inner side end face of the crimped portion 3h. The flat portion 3i of the hub ring 3 is configured with its inner side surface being flat by performing a turning process. The flat portion 3i of the hub ring 3 abuts against the outer side end face of the shoulder portion 22 of the outer joint member 21. The flat portion 3i of the hub ring 3 is configured to protrude to the inner side from the inner side end portion of the crimped portion 3h. The flat portion 3i of the hub ring 3 (the outer diameter of the flat portion 3i) is located radially inward from the inner diameter of the inner ring 4.

[0027] In this way, the hub wheel 3 has a flat portion 3i that abuts against the outer end surface of the shoulder portion 22 of the outer joint member 21, and the flat portion 3i of the hub wheel 3 protrudes toward the inner side from the inner end portion of the crimped portion 3h, and the outer diameter of the flat portion 3i is located radially inward of the inner diameter of the inner ring 4. In this way, the flat portion 3i of the hub wheel 3 protrudes toward the inner side from the inner end portion of the crimped portion 3h, so that the crimped portion 3h can be configured to a size that ensures sufficient strength. In addition, since the outer diameter of the flat portion 3i is located radially inward from the inner diameter of the inner ring 4, the relative amount of slippage at the abutment portion between the hub wheel 3 (flat portion 3i) and the constant velocity universal joint 20 (outer end surface of the shoulder portion 22) can be reduced compared to a case in which the flat portion 3i (at least a part of the flat portion 3i) of the hub wheel 3 is located radially outward from the inner diameter of the inner ring 4. Therefore, the strength of the crimped portion 3h of the hub wheel 3 can be maintained, while the occurrence of stick-slip at the contact portion between the hub wheel 3 and the constant velocity universal joint 20 can be suppressed.

[0028] The flat portion 3i of the hub ring 3 is configured as a surface that is approximately perpendicular to the axial direction. The flat portion 3i of the hub ring 3 is configured as an approximately annular shape centered on the rotation axis X. The radial width A of the flat portion 3i of the hub ring 3 is configured to be approximately the same value at any part in the circumferential direction. The radial width A of the flat portion 3i of the hub ring 3 (the width of the inner surface of the flat portion 3i) is configured to be 3 mm or more. Because of this configuration, it is possible to prevent the surface pressure from becoming high at the contact surface between the hub ring 3 (flat portion 3) and the constant velocity universal joint 20 (the outer end surface of the shoulder portion 22), and it is possible to prevent stick-slip from occurring at the contact portion between the hub ring 3 and the constant velocity universal joint 20.

[0029] The surface of the flat portion 3i of the hub wheel 3 that abuts on the outer end surface of the shoulder portion 22 of the outer joint member 21 (the inner surface of the flat portion 3i) is configured at a perpendicular angle of 0.2 mm or less to the rotation axis X (axial direction). This configuration makes it possible to prevent localized high surface pressure on the abutment surface between the hub wheel 3 (flat portion 3) and the constant velocity universal joint 20 (the outer end surface of the shoulder portion 22). Therefore, it is possible to suppress stick-slip from occurring at the abutment portion between the hub wheel 3 and the constant velocity universal joint 20.

[0030] The inner diameter (inner diameter edge) of the flat portion 3i of the hub wheel 3 is configured with a runout of 1.0 mm or less with respect to the rotation axis X. Because the inner diameter of the flat portion 3i of the hub wheel 3 is configured with a relatively high roundness in this manner, it is possible to prevent localized high surface pressure on the contact surface between the hub wheel 3 (flat portion 3) and the constant velocity universal joint 20 (the outer end surface of the shoulder portion 22). Therefore, it is possible to suppress the occurrence of stick-slip at the contact portion between the hub wheel 3 and the constant velocity universal joint 20.

[0031] The step 3j of the hub wheel 3 is formed by turning the outer diameter side portion (the portion outer diameter side than the flat portion 3i) of the inner side end portion of the crimped portion 3h, so that it is recessed toward the outer side than the flat portion 3i. The step 3j of the hub wheel 3 is disposed adjacent to the flat portion 3i. The step 3j of the hub wheel 3 prevents burrs generated by turning the crimped portion 3h of the hub wheel 3 from contacting the constant velocity universal joint 20 (the outer side end surface of the shoulder portion 22), and prevents the surface pressure from becoming locally high at the contact surface between the hub wheel 3 and the constant velocity universal joint 20. Therefore, it is possible to prevent stick-slip from occurring at the contact portion between the hub wheel 3 and the constant velocity universal joint 20. In addition, since the step portion 3j of the hub wheel 3 is formed by turning on the outer diameter side of the flat portion 3i, the shape of the outer diameter side edge portion of the flat portion 3i can be adjusted, and variations in the surface pressure at the contact surface between the hub wheel 3 and the constant velocity universal joint 20 can be suppressed.

[0032] The depth B of the recess towards the outer side at the step portion 3j of the hub wheel 3 is configured to be 0.1 mm or more. This configuration more reliably prevents burrs generated by turning the crimped portion 3h of the hub wheel 3 from coming into contact with the constant velocity universal joint 20 (the outer end surface of the shoulder portion 22), more reliably preventing localized high surface pressure at the contact surface between the hub wheel 3 and the constant velocity universal joint 20. Therefore, it is possible to more reliably prevent stick-slip from occurring at the contact portion between the hub wheel 3 and the constant velocity universal joint 20.

[0033] Depth B of the recess toward the outer side in step portion 3j of hub wheel 3 is set to 0.5 mm or less. By not making step portion 3j of hub wheel 3 deeper than necessary in this way, the strength of crimped portion 3h of hub wheel 3 can be maintained and the contact surface can be prevented from corroding and becoming stuck due to muddy water or the like entering step portion 3j of hub wheel 3.

[0034] Although a wheel bearing device called a third generation has been exemplified, the wheel bearing device according to the present invention is not limited to this structure and may be, for example, a first or second generation structure in which a pair of inner rings are press-fitted into the small diameter step of the hub ring. Also, although a double row angular ball bearing with ball rows 5 and 6 as rolling elements has been exemplified, the present invention is not limited to this and may be a double row tapered roller bearing using tapered rollers as rolling elements.

[0035] 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]

[0036] 1 Wheel bearing device 2 Outer ring 2a Inner side opening 2b Outer side opening 2c (inner side) outer raceway groove 2d (Outer side) Outer raceway groove 3 Hub wheel 3a Small diameter stepped section 3b Wheel mounting flange 3c Inner raceway groove 3f shaft hole 3h Fastening part 3i flat area 3j Step 4. Inner Circle 4a Inner raceway groove 5 Inner ball row 6 Outer ball row 20 Constant velocity universal joint 21 Outer joint member 22 Shoulder A: Radial width of the flat part of the hub B Depth of step on hub X Rotation

Claims

1. an outer member having double rows of outer raceway grooves on an inner periphery; an inner member including a hub wheel having a small diameter step at an inner end of an outer periphery, and an inner ring provided on the small diameter step of the hub wheel, the hub wheel and the inner ring being integrated by crimping an inner end of the small diameter step of the hub wheel to form a crimped portion, the hub wheel and the inner ring being integrated, and having double row inner raceway grooves facing the double row outer raceway grooves; a double row of rolling elements rollably accommodated between the raceway grooves of the outer member and the inner member; a constant velocity universal joint having a shoulder portion and a shaft portion extending axially from the shoulder portion, the shaft portion being inserted into a shaft hole of the hub wheel and connected to the hub wheel, the hub wheel has a flat portion that comes into contact with an outer end surface of the shoulder portion of the constant velocity universal joint, A wheel bearing device, wherein the flat portion of the hub wheel protrudes toward the inner side from the inner end portion of the crimped portion, and the outer diameter of the flat portion is positioned radially inward relative to the inner diameter of the inner ring.

2. 2. The wheel bearing device according to claim 1, wherein the flat portion of the hub wheel has a radial width of 3 mm or more.

3. 2. The wheel bearing device according to claim 1, wherein a surface of said flat portion of said hub wheel that abuts against an outer end surface of said shoulder portion of said constant velocity universal joint is configured to have a perpendicularity of 0.2 mm or less with respect to an axial direction.

4. 2. The wheel bearing device according to claim 1, wherein an inner diameter of the flat portion of the hub ring has a runout of 1.0 mm or less with respect to a rotation axis.

5. the hub wheel has a step portion formed at an inner end of the crimped portion so as to be recessed toward the outer side relative to the flat portion, 2. The wheel bearing device according to claim 1, wherein the stepped portion of the hub wheel is recessed to a depth of 0.1 mm or more toward the outer side relative to the flat portion.

6. 6. The wheel bearing device according to claim 5, wherein the depth of the step portion of the hub wheel recessed toward the outer side is 0.5 mm or less.

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