Bearing device for wheel

Abstract

In a bearing device for a wheel, stick slip at a contact portion between a hub ring and a constant velocity universal joint can be suppressed, the strength of a caulking portion can be maintained, and muddy water and the like can be suppressed from entering a step portion to corrode a contact surface to be fixedly connected. A bearing device for a wheel is provided with: an outer ring having an outer raceway groove; an inner member including a hub ring and an inner ring provided in a small-diameter stepped portion of the hub ring, the inner member having a caulking portion formed at an inner side end portion of the small-diameter stepped portion and having an inner track groove; a ball accommodated between the outer rail groove and the inner rail groove; and a constant velocity universal joint connected to the hub ring, the hub ring having a flat portion that comes into contact with the constant velocity universal joint and a stepped portion formed at an inner-side end portion of the swaging portion, the stepped portion having a depth of 0.1 mm or more and 0.5 mm or less than the flat portion.

Description

Technical Field

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

[0002] In the past, a wheel bearing device is known for supporting a wheel in a suspension device of a motor vehicle or the like so as to be rotatable. Among the wheel bearing devices, the following wheel bearing device is known, which comprises: an outer member having a double-row outer raceway groove on the inner periphery; an inner member including a hub ring having a small-diameter step portion at the inner side end of the outer periphery, and an inner ring provided on the small-diameter step portion of the hub ring, wherein the hub ring and the inner ring are integrated by riveting the inner side end of the small-diameter step portion of the hub ring to form a riveted portion, and the inner member has a double-row inner raceway groove opposed to the double-row outer raceway groove; a double-row rolling element freely accommodated between the two raceway grooves of the outer member and the inner member; and a constant velocity universal joint connected to the hub ring, wherein the hub ring has a flat portion abutting against the outer side end face of the constant velocity universal joint, and a step portion formed at the inner side end of the riveted portion in a manner recessed toward the outer side (see Patent Document 1).

[0003] Prior Art Literature

[0004] Patent Literature

[0005] Patent Document 1: Japanese Patent Application Publication No. 2007-224954 Summary of the invention

[0006] Problems to be solved by the invention

[0007] Here, the burr generated by turning the riveted portion of the hub ring abuts against the constant velocity universal joint (the outer side end surface of the shoulder of the constant velocity universal joint), thereby locally increasing the surface pressure, and sometimes causing stick-slip at the abutting portion between the hub ring and the constant velocity universal joint. However, in the wheel bearing device, the abutting of the burr with the constant velocity universal joint is suppressed by the step portion of the hub ring, thereby suppressing the stick-slip at the abutting portion between the hub ring and the constant velocity universal joint. However, even if the hub ring has a structure with a step portion, if the depth of the step portion is too shallow, there is a situation where the burr generated by turning the riveted portion of the hub ring abuts against the constant velocity universal joint. In addition, even if the hub ring has a structure with a step portion, if the depth of the step portion is too deep, the strength of the riveted portion of the hub ring may be reduced, and muddy water and the like are more likely to enter the step portion of the hub ring.

[0008] Therefore, in the present invention, the purpose is to provide a wheel bearing device that can suppress the sticking and slipping at the abutting portion between the hub ring and the constant velocity universal joint, maintain the strength of the riveted portion of the hub ring, and suppress mud and water from entering the step portion of the hub ring to corrode the abutting surface and fix it.

[0009] Means for solving problems

[0010] That is, a wheel bearing device comprises: an outer member having a double-row outer track groove on its inner circumference; an inner member including a hub ring having a small-diameter step portion at the inner side end portion of the outer circumference and an inner ring arranged on the small-diameter step portion of the hub ring, wherein the hub ring and the inner ring are integrated by riveting the inner side end portion of the small-diameter step portion of the hub ring, and the inner member has a double-row inner track groove opposite to the double-row outer track groove; and double-row rolling elements are freely accommodated in the outer member and the inner member. Between the two track grooves of the inner member; and a constant velocity universal joint, which has a shoulder and a shaft extending axially from the shoulder, the shaft being inserted into the axial hole of the hub ring and connected to the hub ring, wherein the hub ring has: a flat portion abutting against the outer side end surface of the shoulder of the constant velocity universal joint; and a step portion formed at the inner side end portion of the riveted portion in a manner recessed outwardly than the flat portion, the depth of the step portion of the hub ring recessed outwardly than the flat portion being greater than 0.1 mm and less than 0.5 mm.

[0011] Effects of the Invention

[0012] The present invention has the following effects.

[0013] That is, according to the present invention, stick-slip can be suppressed at the contact portion between the hub ring and the constant velocity universal joint, the strength of the rivet portion of the hub ring can be maintained, and muddy water etc. can be suppressed from entering the step portion of the hub ring to corrode the contact surface and fix it. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 It is a cross-sectional view showing a wheel bearing device according to an embodiment of the present invention.

[0015] Figure 2 It is an enlarged cross-sectional view showing the wheel bearing device.

[0016] Description of reference numerals:

[0017] 1Wheel bearing device

[0018] 2 Outer ring

[0019] 2a Inner side opening

[0020] 2b Outer side opening

[0021] 2c (Inner side) Outer track groove

[0022] 2d (outer side) outer track groove

[0023] 3 wheel hub

[0024] 3a Path Steps

[0025] 3b Wheel mounting flange

[0026] 3c inner track groove

[0027] 3f shaft hole

[0028] 3h riveting department

[0029] 3i Flat part

[0030] 3j step part

[0031] 4Inner circle

[0032] 4a Inner track groove

[0033] 5 Inner side ball row

[0034] 6 outer side ball row

[0035] 20 Constant velocity universal coupling

[0036] 21 Outer coupling member

[0037] 22 Shoulder

[0038] A The radial width of the flat portion of the hub rim

[0039] B Depth of the step portion of the hub

[0040] C: Spline diameter of the hub ring shaft hole

[0041] X axis of rotation. DETAILED DESCRIPTION

[0042] Hereinafter, a mode for carrying out the present invention will be described using the drawings.

[0043] Figure 1 The wheel bearing device 1 shown is one embodiment of the wheel bearing device of the present invention, and is used to rotatably support a wheel in a suspension device of a vehicle such as an automobile.

[0044] The wheel bearing device 1 has a structure known 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, a double row of inner ball rows 5 and an outer ball row 6 as rolling rows, an inner side sealing member 9 and an outer side sealing member 10, and a constant velocity universal joint 20.

[0045] Here, the inner side indicates the vehicle body side of the wheel bearing device 1 when installed on the vehicle body, and the outer side indicates the wheel side of the wheel bearing device 1 when installed on the vehicle body. In addition, the axial direction indicates the direction along the rotation axis X of the wheel bearing device 1, with one axial end side being the outer side and the other axial end side being the inner side.

[0046] like Figure 1 As shown, an inner side opening 2a capable of being fitted with an inner side sealing member 9 is formed at the inner side end of the outer ring 2. An outer side opening 2b capable of being fitted with an outer side sealing member 10 is formed at the outer side end of the outer ring 2. An inner side outer side track groove 2c and an outer side outer side track groove 2d are formed on the inner circumferential surface of the outer ring 2.

[0047] 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 for inserting fastening members (here, bolts) for fastening the vehicle body member and the outer ring 2.

[0048] A small-diameter step portion 3a having a smaller diameter than that of the outer side end is formed at the inner side end portion of the outer peripheral surface 3g of the hub ring 3. A wheel mounting flange 3b for mounting a wheel is integrally formed at the outer side end portion of the hub ring 3. A plurality of bolt holes 3d are formed in the wheel mounting flange 3b. Hub bolts 3e for fastening the hub ring 3 to the wheel or brake components are pressed into the bolt holes 3d. The wheel mounting flange 3b is an example of a hub flange extending radially outward. A spline for torque transmission is formed on the inner peripheral surface of the axial hole 3f of the hub ring 3.

[0049] On the outer peripheral surface 3g of the hub ring 3, an inner track groove 3c on the outer side is provided in a manner opposite to the outer track groove 2d on the outer side of the outer ring 2. That is, on the outer side of the inner member, the inner track groove 3c is formed by the hub ring 3. The outer side sealing member 10 is fitted into the outer side opening end of the annular space formed by the outer ring 2 and the hub ring 3, thereby sealing the outer side opening end. The outer side sealing member 10 is an example of a sealing device.

[0050] The inner ring 4 is arranged on the small-diameter step portion 3a of the hub ring 3. The inner ring 4 is pressed into the small-diameter step portion 3a with a predetermined interference. Moreover, by riveting the inner side end of the small-diameter step portion 3a of the hub ring 3 to make it plastically deformed, the hub ring 3 and the inner ring 4 are integrated to prevent the inner ring 4 from axially disengaging from the hub ring 3. The inner ring 4 applies preload to the inner side ball row 5 and the outer side ball row 6 as rolling rows. An inner side inner track groove 4a is provided on the outer peripheral surface of the inner ring 4 in a manner opposite to the outer side track groove 2c on the inner side of the outer ring 2. That is, on the inner side of the inner member, the inner side track groove 4a is formed by the inner ring 4.

[0051] The inner side ball row 5 and the outer side ball row 6 as rolling rows are formed by holding a plurality of balls 7 as rolling elements by using a retainer 8. The inner side ball row 5 is sandwiched between the inner side track groove 4a of the inner ring 4 and the outer side track groove 2c on the inner side of the outer ring 2 in a manner that allows for free rolling. The outer side ball row 6 is sandwiched between the inner side track groove 3c of the hub ring 3 and the outer side track groove 2d on the outer side of the outer ring 2 in a manner that allows for free rolling. In other words, the inner side ball row 5 and the outer side ball row 6 are freely accommodated between the two track grooves of the outer member and the inner member in a manner that allows for free rolling. In the wheel bearing device 1, a double row angular contact ball bearing is formed by the outer ring 2, the hub ring 3 and the inner ring 4, the inner side ball row 5, and the outer side ball row 6.

[0052] The constant velocity universal joint 20 is provided at one end of an intermediate shaft (not shown) constituting a drive shaft, and is connected to the hub 3. The constant velocity universal joint 20 includes an outer joint member 21, an inner joint member (not shown) having a rolling groove formed on the outer peripheral surface thereof and facing the rolling groove of the outer joint member 21, and balls (not shown) assembled between the rolling groove of the outer joint member 21 and the rolling groove of the inner joint member.

[0053] The outer coupling member 21 includes a shoulder portion 22 at the bottom of a cup-shaped mouth and a shaft portion 23 extending axially from the shoulder portion 22. The shoulder portion 22 of the outer coupling member 21 is formed integrally with the shaft portion 23. A spline is formed on the outer periphery of the shaft portion 23 of the outer coupling member 21, and an external thread is formed at the end of the spline. The shaft portion 23 of the outer coupling member 21 is inserted into the shaft hole 3f of the hub ring 3 so that the spline of the shaft portion 23 of the outer coupling member 21 is engaged with the spline of the hub ring 3. Furthermore, the fixing nut 11 is fastened to the external thread of the shaft portion 23 of the outer coupling member 21 with a prescribed tightening torque, thereby being configured to be able to transmit the torque from the drive shaft to the hub ring 3 via the outer coupling member 21.

[0054] like Figure 1 or Figure 2As shown, the hub 3 has a riveted portion 3h, a flat portion 3i, and a stepped portion 3j. The riveted portion 3h of the hub 3 is formed by riveting the inner side end portion of the small diameter stepped portion 3a in the hub 3. The flat portion 3i of the hub 3 is formed on the inner side end surface of the riveted portion 3h. The flat portion 3i of the hub 3 is configured to protrude inward from the inner side end portion of the riveted portion 3h. The inner side surface of the flat portion 3i of the hub 3 is formed by a flat surface by turning. The flat portion 3i of the hub 3 abuts against the outer side end surface of the shoulder 22 of the outer coupling member 21.

[0055] The step portion 3j of the hub 3 is formed to be recessed outward from the flat portion 3i by turning the outer diameter side portion (the outer diameter side portion than the flat portion 3i) of the inner side end portion of the rivet portion 3h. The step portion 3j of the hub 3 is arranged adjacent to the flat portion 3i. The step portion 3j of the hub 3 can prevent the burrs generated by turning the rivet portion 3h of the hub 3 from abutting against the constant velocity universal joint 20 (the outer side end surface of the shoulder 22), thereby preventing the surface pressure from locally increasing at the abutting surface between the hub 3 and the constant velocity universal joint 20. Therefore, it is possible to prevent the occurrence of stick-slip at the abutting portion between the hub 3 and the constant velocity universal joint 20. In addition, the step portion 3j of the hub ring 3 is formed on the outer diameter side of the flat portion 3i by turning, so the shape of the outer diameter side edge portion of the flat portion 3i can be adjusted, which can suppress the deviation of the surface pressure of the abutment surface between the hub ring 3 and the constant velocity universal joint 20.

[0056] The depth B of the step portion 3j of the hub 3 that is recessed outward is 0.1 mm or more. With this configuration, it is possible to more reliably suppress the burrs generated by turning the rivet portion 3h of the hub 3 from contacting the constant velocity universal joint 20 (the outer end surface of the shoulder 22), thereby more reliably preventing the surface pressure from locally increasing at the contact surface between the hub 3 and the constant velocity universal joint 20. Therefore, it is possible to more reliably suppress the occurrence of stick-slip at the contact portion between the hub 3 and the constant velocity universal joint 20.

[0057] The depth B of the step portion 3j of the hub 3 that is recessed outward is less than 0.5 mm. By not making the step portion 3j of the hub 3 too deep, the strength of the rivet portion 3h of the hub 3 can be maintained, and muddy water or the like can be prevented from entering the step portion 3j of the hub 3 and corroding the abutting surface and fixing it.

[0058] The peak Rku of the roughness curve of the flat portion 3i of the hub wheel 3 that contacts the outer end face of the shoulder 22 of the outer joint member 21 (the inner end face of the flat portion 3i) is 3 or less. The peak Rku of the roughness curve indicates the peak Rku of the roughness curve specified by Japanese Industrial Standard (JIS) B0601:2013. By configuring in this way, the sharpness of the concavities and convexities of the flat portion 3i of the hub wheel 3 that contacts the outer end face of the shoulder 22 of the outer joint member 21 can be made relatively small, thereby more reliably suppressing the surface pressure from increasing at the contact surface between the hub wheel 3 (flat portion 3) and the constant velocity universal joint 20 (the outer end face of the shoulder 22). Therefore, it is possible to more reliably suppress the occurrence of stick-slip at the contact portion between the hub wheel 3 and the constant velocity universal joint 20.

[0059] The radial width A of the flat portion 3i of the hub wheel 3 (the width of the inner surface of the flat portion 3i) is 3 mm or more. The inner diameter of the flat portion 3i of the hub wheel 3 is configured to be greater than 1.4 times and less than 1.6 times the spline diameter C of the shaft hole 3f of the hub wheel 3. The outer diameter of the flat portion 3i of the hub wheel 3 is configured to be greater than 1.7 times and less than 1.9 times the spline diameter C of the shaft hole 3f of the hub wheel 3. By configuring the radial width A of the flat portion 3i of the hub wheel 3 (the width of the inner surface of the flat portion 3i) in this way, it is possible to more reliably suppress the surface pressure from increasing at the contact surface between the hub wheel 3 (flat portion 3i) and the constant velocity universal joint 20 (the outer end surface of the shoulder 22). Therefore, it is possible to more reliably suppress the occurrence of stick-slip at the contact portion between the hub wheel 3 and the constant velocity universal joint 20. It should be noted that the value of the spline diameter C is expressed as a nominal size.

[0060] Here, when the inner diameter of the flat portion 3i of the hub wheel 3 is smaller than 1.4 times the spline diameter C of the shaft hole 3f of the hub wheel 3, the surface pressure can be suppressed from increasing, but the radial width A of the flat portion 3i needs to be extended in a manner close to the inner diameter surface side of the hub wheel 3, so the inner peripheral surface of the hub wheel 3 itself needs to be extended toward the inner diameter side. As a result, the space between the hub wheel 3 and the constant velocity universal joint 20 located on the inner diameter side of the flat portion 3i cannot be fully ensured, and there is a problem of interference between the hub wheel 3 and the constant velocity universal joint 20. On the contrary, when the inner diameter of the flat portion 3i of the hub wheel 3 is larger than 1.6 times the spline diameter C of the shaft hole 3f of the hub wheel 3, the surface pressure becomes high, and stick-slip is likely to occur.

[0061] When the outer diameter of the flat portion 3i of the hub ring 3 is less than 1.7 times the spline diameter C of the shaft hole 3f of the hub ring 3, the radial width A of the flat portion 3i becomes smaller, so the surface pressure becomes higher, and stick-slip is likely to occur. On the contrary, when the outer diameter of the flat portion 3i of the hub ring 3 is larger than 1.9 times the spline diameter C of the shaft hole 3f of the hub ring 3, the step portion 3j of the hub ring 3 cannot be fully ensured, and the space for avoiding burrs becomes insufficient, the burrs abut against the constant velocity universal joint 20, the surface pressure locally becomes higher, and stick-slip is likely to occur.

[0062] The surface of the flat portion 3i of the hub wheel 3 that contacts the outer end surface of the shoulder portion 22 of the outer coupling member 21 (the surface on the inner side of the flat portion 3i) is configured to have a right angle of 0.2 mm or less with respect to the rotation axis X (axial direction). By configuring in this way, it is possible to prevent the surface pressure from being locally increased at 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.

[0063] The inner diameter (inner diameter edge) of the flat portion 3i of the hub wheel 3 is configured to fluctuate by less than 1.0 mm relative to the rotation axis X. In this way, by configuring the inner diameter of the flat portion 3i of the hub wheel 3 to have a relatively high roundness, it is possible to prevent the surface pressure from being locally increased at the contact surface between the hub wheel 3 (flat portion 3) and the constant velocity universal joint 20 (outer side end surface of the shoulder 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.

[0064] It should be noted that, although the wheel bearing device called the third generation is illustrated, the wheel bearing device of the present invention is not limited to such a structure, and for example, it may be a first generation or second generation structure in which a pair of inner rings are pressed into the small diameter step portion of the hub ring. In addition, a double row angular contact ball bearing in which the rolling elements are ball rows 5 and 6 is illustrated, but it is not limited to this, and a double row tapered roller bearing in which the rolling elements are tapered rollers may also be used.

[0065] The above describes the embodiments of the present invention, but the present invention is not limited by such embodiments, and is exemplified at most. It goes without saying that it can be implemented in various ways without departing from the scope of the present invention. The scope of the present invention is shown by the scope of the patent claims, and includes the meanings equivalent to the records of the scope of the patent claims and all changes within the scope.

Claims

1. A wheel bearing device, comprising: An outer member having double rows of outer track grooves on the inner periphery; An inner member, comprising a hub ring having a small-diameter step portion at an inner end portion of an outer circumference and an inner ring provided on the small-diameter step portion of the hub ring, wherein the hub ring and the inner ring are integrated by riveting the inner end portion of the small-diameter step portion of the hub ring to form a riveted portion, and the inner member has a double-row inner track groove opposed to the double-row outer track groove; Double-row rolling elements are freely accommodated between the two track grooves of the outer member and the inner member; as well as A constant velocity universal joint having a shoulder portion and a shaft portion extending axially from the shoulder portion, wherein the shaft portion is inserted into an axial hole of the hub ring and connected to the hub ring, wherein: The hub ring has: a flat portion that abuts against an outer end surface of the shoulder of the constant velocity universal joint; and a step portion formed at an inner end portion of the rivet portion in a manner recessed outward from the flat portion, The depth of the step portion of the hub wheel, which is recessed outward from the flat portion, is 0.1 mm or more and 0.5 mm or less.

2. The wheel bearing device according to claim 1, wherein: A kurtosis Rku of a roughness curve of a surface of the flat portion of the hub wheel that contacts an outer end surface of the shoulder portion of the constant velocity universal joint is 3 or less.

3. The wheel bearing device according to claim 1, wherein: The inner diameter of the flat portion of the hub ring is in a range of greater than 1.4 times and less than 1.6 times the spline diameter of the shaft hole of the hub ring, and the outer diameter of the flat portion of the hub ring is in a range of greater than 1.7 times and less than 1.9 times the spline diameter of the shaft hole of the hub ring.

4. The wheel bearing device according to claim 1, wherein: The surface of the flat portion of the hub wheel that contacts the outer end surface of the shoulder portion of the constant velocity universal joint has a perpendicular angle of 0.2 mm or less with respect to the axial direction.

5. The wheel bearing device according to claim 1, wherein: The inner diameter of the flat portion of the hub wheel fluctuates with respect to the rotation axis by 1.0 mm or less.

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