JP2009250296A - Bearing device for wheel - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a bearing device for a wheel which can be processed in lightweight and miniaturization, and improve a strength and a durability of hub wheel. <P>SOLUTION: An inner ring 8 at outer side is characterized in that a shoulder 13, extending from a large-diameter side of its inner side track surface 8a to axial direction, is formed, in that thickness is set roughly uniform, in that a center position of a curvature radius Ri of a large-end inner-diameter section 18 of the inner ring 8 and a center position of a curvature radius Rw of a ball 10 are set at roughly the same position, in that at a position at which a line of action L of angle of contact of the inner ring 8 intersects with a hub wheel 1, a clearance is kept by making the inner ring 8 not contact with the hub wheel 1, and a corner section B between a shoulder 1a of the inner ring 1 and a small-diameter step section 1b is constituted by a composite R consisting of curvature radii Rb, Rc, and in that the curvature radius Rb at the shoulder 1a side is set smaller in Rb<Ra than a maximum curvature radius Ra when corner R is set to be single R, and a curvature radius Rc at the small-diameter step section 1b side is set greater in Rc>Ra than the curvature radius Ra. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention provides a wheel bearing device for rotatably supporting a wheel of a vehicle such as an automobile, particularly a first or second generation structure in which a pair of inner rings are press-fitted and fixed. The present invention relates to a wheel bearing device that is improved in strength and durability.

  There are two types of wheel bearing devices of the first generation or second generation structure in which a pair of inner rings are press-fitted into the small-diameter step portion of the hub ring, for driving wheels and for driven wheels, but it goes without saying that the cost is reduced. In addition, lighter and more compact for improving fuel efficiency. On the other hand, in such a wheel bearing device, the corner of the hub wheel at the abutting portion with the large end surface of the inner ring, that is, the corner of the shoulder of the hub wheel and the small-diameter stepped portion is an arc having a single radius of curvature. In general, it is formed of a plane (single R). Here, in such a wheel bearing device whose cross-section has been reduced in order to reduce the weight, the length of the abutting portion (contact area) with the large end surface of the inner ring within a constrained space in order to ensure the rigidity of the inner ring. ) Must be increased. However, when the length of the abutting part is increased, the corner becomes excessively small.In particular, when a large moment load is repeatedly applied to the hub wheel via the wheel mounting flange when the vehicle turns, excessive stress is applied to the corner. As a result, there was a risk that the mechanical strength of the hub wheel would be significantly lowered and the durability would be reduced.

  Here, when the curvature radius of the single R is increased in order to reduce the stress generated in the corner, interference occurs between the corner and the chamfered portion of the inner ring. The interference between the corners and the chamfered portion of the inner ring induces misalignment, and the durability of the inner ring may be reduced. Therefore, it is necessary to suppress the dimensional variation as much as possible in the processing of the corners, but this causes an increase in the manufacturing cost, and there is a limit to the regulation of the dimensional variation when the variation due to heat treatment deformation is taken into consideration.

As a solution to such a problem, the present applicant has proposed a wheel bearing device as shown in FIG. In this wheel bearing device, the shoulder 52 of the hub wheel 51 and the corner A of the small-diameter stepped portion 53 are composed of a composite R composed of a plurality of curvature radii b and c, and the curvature radius b is a single R. And the radius of curvature c is set to be larger than the radius of curvature a (b <a <c). As a result, the length X of the abutting portion with the large end surface 55 of the inner ring 54 can be ensured in a restricted space to increase the rigidity of the inner ring 54, and the stress generated at the corner A can be suppressed, thereby reducing the hub ring. It is possible to provide a wheel bearing device in which the durability of 51 is improved. Further, in the processing of the corner portion A, interference with the chamfered portion 56 of the inner ring 54 can be prevented without suppressing dimensional variation more than necessary, and the cost can be reduced.
JP 2007-210356 A

  However, as the cross-section is reduced to reduce the weight, when the radius of curvature c and the small diameter step portion 53 and the radius of curvature b and the shoulder 52 are small at the corner A of the hub wheel 51, the hub wheel 51 is reduced. Even if the corner portion A is changed to such a composite R, there is a limit to significant improvement in durability.

  The present invention has been made in view of such circumstances, and an object of the present invention is to provide a wheel bearing device that achieves light weight and compactness and improves the strength and durability of the hub wheel.

  In order to achieve such an object, the invention according to claim 1 of the present invention has a wheel mounting flange for mounting a wheel at one end portion, and axially extends from the wheel mounting flange via a shoulder portion. A hub wheel formed with an extending small-diameter step portion, and a wheel bearing press-fitted into the small-diameter step portion of the hub wheel through a predetermined shimeshiro, the wheel bearing having a double-row arc shape on the inner periphery An outer member formed integrally with the outer rolling surface, a pair of inner rings formed on the outer periphery with an arcuate inner rolling surface facing the outer rolling surface of the double row, the inner ring and the outer A double row of balls accommodated between both rolling surfaces of the side member, and a seal attached to an opening of an annular space formed between the outer member and the inner ring, and the pair of inner rings A double-sided angular contact ball bearing of back-to-back type is formed by abutting the small end faces together. In the bearing device for a wheel, at least the inner ring on the outer side of the pair of inner rings has a shoulder portion extending in the axial direction from the large diameter side of the inner rolling surface thereof, and the wall thickness is substantially uniform over the entire width. And the center position of the radius of curvature of the inner diameter portion of the large end of the inner ring and the center position of the radius of curvature of the ball are set to substantially the same position, and the action line of the contact angle of the inner ring is At the position intersecting with the hub wheel, the inner ring and the hub wheel are not in contact with each other, and a gap is secured.

  As described above, in the wheel bearing device configured by the back-to-back type double row angular contact ball bearing in which the wheel bearing press-fitted and fixed to the hub wheel includes a pair of inner rings, at least the inner ring on the outer side of the pair of inner rings. However, a shoulder extending in the axial direction from the large-diameter side of the inner raceway surface is formed, the wall thickness is set substantially uniform over the entire width, and the radius of curvature of the inner diameter portion of the large end of the inner ring The center position of the ball and the center position of the radius of curvature of the ball are set at approximately the same position, and the inner ring and the hub ring do not contact each other at the position where the line of action of the contact angle of the inner ring intersects with the hub ring. Therefore, it is possible to provide a wheel bearing device that is lighter and more compact, has increased design freedom in the shape and dimensions of the corners of the hub wheel, and has improved the strength and durability of the hub wheel. Can do.

  Preferably, as in the invention described in claim 2, if the inner ring on the outer side is formed from a pipe material by cold rolling, productivity is improved, yield is improved, and cost can be reduced.

  Further, as in the invention described in claim 3, the corner portion of the shoulder portion of the hub wheel and the small-diameter step portion is composed of a composite R having curvature radii Rb and Rc, and on the shoulder side. The curvature radius Rb is set to Rb <Ra smaller than the maximum curvature radius Ra when the corner R is a single R, and the curvature radius Rc on the small diameter step portion side is larger than the curvature radius Ra. If it is set to Ra, even if a large moment load is applied to the hub wheel via the wheel mounting flange when the vehicle turns, the stress generated at the corner is suppressed, and the hub wheel is reduced in weight and size. The strength and durability can be improved.

  Further, as in the invention according to claim 4, the corners of the shoulder portion of the hub wheel and the small-diameter stepped portion are formed by a composite R having curvature radii Rb and Rc, and a tangent line smoothly connecting the composite R. If a mortar-shaped recess extending in the axial direction is formed in the outer side end of the hub wheel by forging and the thickness of the corner is set to be approximately uniform, the corner R is simply The minimum thickness can be increased as compared with the hub wheel when it is 1R, and the strength and durability of the hub wheel can be improved.

  Further, as in the invention described in claim 5, the curvature radius Rc may be set to be twice or more of the curvature radius Rb.

  Further, as in the invention described in claim 6, the axial dimension La of the corner portion of the hub wheel may be set to 1.5 times or more of the radial dimension Lr.

  A wheel bearing device according to the present invention has a wheel mounting flange for mounting a wheel at one end, and a hub wheel formed with a small-diameter step portion extending axially from the wheel mounting flange via a shoulder. And a wheel bearing that is press-fitted into the small-diameter step portion of the hub wheel via a predetermined scissors, and this wheel bearing has a double-row arc-shaped outer raceway formed integrally on the inner periphery. The outer member, a pair of inner rings formed on the outer periphery with an arcuate inner rolling surface facing the double row outer rolling surface, and the inner ring and the outer member are accommodated between both rolling surfaces. A double row of balls and a seal attached to an opening of an annular space formed between the outer member and the inner ring, and the small end surfaces of the pair of inner rings abut each other in a butted state. In the wheel bearing device constituting the back-to-back type double row angular contact ball bearing, At least the inner ring on the outer side of the pair of inner rings has a shoulder portion extending in the axial direction from the large diameter side of the inner rolling surface, the wall thickness is set substantially uniformly over the entire width, and the inner ring The central position of the radius of curvature of the inner diameter portion of the large end of the ball and the central position of the radius of curvature of the ball are set at substantially the same position, and the line of action of the contact angle of the inner ring intersects the hub ring. The inner ring and hub ring do not come into contact with each other, and a clearance is secured. This reduces weight and size, and increases the design freedom of the shape and dimensions of the corners of the hub ring, thereby increasing the strength and durability of the hub ring. It is possible to provide a wheel bearing device with improved performance.

  A hub wheel integrally having a wheel mounting flange for mounting a wheel at one end, and having a cylindrical small-diameter step portion extending in an axial direction from the wheel mounting flange via a shoulder portion, and a small diameter of the hub wheel A wheel bearing that is press-fitted into the step portion through a predetermined squeeze, and the wheel bearing includes an outer member formed integrally with a double row arc-shaped outer rolling surface on the inner periphery, and an outer periphery A pair of inner rings formed with arc-shaped inner rolling surfaces facing the outer surfaces of the double rows, and double rows of balls accommodated between the inner races and both rolling surfaces of the outer member; And a seal mounted in an opening of an annular space formed between the outer member and the inner ring, and a pair of inner ends of the pair of inner rings abut each other in a butted state to form a back-to-back type double row In the wheel bearing device that constitutes the angular ball bearing, at least one of the pair of inner rings The inner ring on the outer side is formed with a shoulder extending in the axial direction from the large diameter side of the inner rolling surface, the wall thickness is set substantially uniform over the entire width, and the inner end of the inner ring has a large end. The inner ring and the hub are located at a position where the center position of the radius of curvature of the inner diameter portion and the center position of the radius of curvature of the ball are set at substantially the same position, and the line of action of the contact angle of the inner ring intersects the hub ring. A clearance is secured without contacting the wheel, and a corner of the shoulder portion of the hub wheel and the small-diameter step portion is composed of a composite R composed of curvature radii Rb and Rc. Rb is set to Rb <Ra smaller than the maximum curvature radius Ra when the corner R is a single R, and the curvature radius Rc on the small diameter step portion side is larger than the curvature radius Ra so that Rc> Ra. Is set.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
1 is a longitudinal sectional view showing a first embodiment of a wheel bearing device according to the present invention, FIG. 2 is a longitudinal sectional view showing the wheel bearing of FIG. 1, and FIG. 3 is an enlarged view of a main part of FIG. 4A is an enlarged view of the main part of the single inner ring of FIG. 3, and FIG. 4B is an enlarged view of the main part of the single hub wheel of FIG. In the following description, the side closer to the outer side of the vehicle when assembled to the vehicle is referred to as the outer side (left side in FIG. 1), and the side closer to the center is referred to as the inner side (right side in FIG. 1).

  This wheel bearing device has a first generation structure on the drive wheel side, and includes a hub wheel 1 and a wheel bearing 2 attached to the hub wheel 1. A constant velocity universal joint 3 is fitted into the hub wheel 1 so as to be able to transmit torque, and the hub wheel 1 and the constant velocity universal joint 3 are connected to each other via a fixing nut 4 so as to be separable in the axial direction.

  The hub wheel 1 has a wheel attachment flange 5 for attaching a wheel (not shown) to an end portion on the outer side, and a cylindrical shape extending from the wheel attachment flange 5 to the outer periphery in the axial direction via a shoulder portion 1a. A small-diameter step portion 1b is formed, and a serration (or spline) 1c for torque transmission is formed on the inner periphery. In the circumferential direction of the wheel mounting flange 5, hub bolts 5 a are planted at equal intervals. The hub wheel 1 is made of medium and high carbon steel containing carbon of 0.40 to 0.80 wt% such as S53C, and remains in the structure and hardness after forging. In addition, tempering is performed after forging to increase fatigue strength against moment load, or surface hardness is set to a range of 50 to 64 HRC by induction hardening from shoulder 1a to small diameter step 1b. May be.

  The constant velocity universal joint 3 includes an outer joint member 14, a joint inner ring (not shown), a cage, and a torque transmission ball. The outer joint member 14 is formed of medium-high carbon steel containing carbon of 0.40 to 0.80 wt% such as S53C, and has a cup-shaped mouth portion 15, a shoulder portion 16 serving as a bottom portion of the mouth portion 15, and the shoulder portion. A shaft portion 17 extending in the axial direction from 16 is integrally provided. A serration 17a that engages with the serration 1c of the hub wheel 1 is formed on the outer periphery of the shaft portion 17, and a male screw 17b is formed at the end of the serration 17a.

  In this wheel bearing 2, the shaft portion 17 of the outer joint member 14 is connected to the hub wheel 1 through the serrations 1c and 17a until the shoulder portion 16 of the outer joint member 14 abuts with the large end surface (back side) 8b of the inner ring 8. And a pair of inner rings 8 and 8 are press-fitted into the small-diameter step portion 1b of the hub wheel 1 through a predetermined shimiro while being sandwiched between the shoulder part 1a of the hub wheel 1 and the shoulder part 16 of the outer joint member 14. Has been. A predetermined bearing preload is applied to the male screw 17b by tightening the fixing nut 4 with a predetermined tightening torque. By applying this preload, the bearing rigidity is increased and the rolling fatigue life of the bearing is improved.

  The wheel bearing 2 is fitted into the knuckle 6, and as shown in an enlarged view in FIG. 2, an outer member 7 in which double row arc-shaped outer rolling surfaces 7a, 7a are integrally formed on the inner periphery, A pair of inner rings 8, 8 each having an arcuate inner rolling surface 8 a facing the double row outer rolling surfaces 7 a, 7 a on the outer periphery, and a cage 9, 9 between both rolling surfaces. Double-row balls 10 and 10 accommodated so as to roll freely, and seals 11 and 12 attached to openings of an annular space formed between the outer member 7 and the inner ring 8 are provided. The small end faces (front side) 8c and 8c of the inner rings 8 and 8 abut each other in a butted state to constitute a so-called back-to-back type double row angular ball bearing.

  Here, the outer member 7 is made of high carbon chrome bearing steel such as SUJ2, and is hardened in the range of 54 to 64 HRC up to the core portion by quenching. On the other hand, the inner ring 8 is formed by plastic working such as cold rolling or pressing after annealing a pipe material made of high carbon chromium bearing steel such as SUJ2 or carburized steel such as SCr420 or SCM415. In the case of bearing steel, the surface hardness is set to a range of 54 to 64 HRC by submerged quenching or induction quenching, and in the case of carburized steel, the surface hardness is in the range of 54 to 64 HRC. In addition to this, the material of the outer member 7 and the inner ring 8 is SCM440, cold rolled steel (JIS standard SPCC, etc.), carbon steel such as S50C to S55C, or eutectoid steel around 0.8 wt% carbon. Can be illustrated. In the case of carbon steel, the inner rolling surface 8a is hardened by induction hardening to a surface hardness in the range of 54 to 64 HRC to improve the rolling fatigue life. These rolling surfaces 8a are formed with predetermined dimensions and accuracy by grinding. After that, superfinishing is performed as necessary.

  The inner ring 8 may be formed by a general process of heat treatment and grinding through hot forging, turning, and cutting after cutting the bar material, but in this embodiment, the pipe that is the material. By rolling from the material, an arc-shaped inner rolling surface 8a and a shoulder 13 extending in the axial direction from the large diameter side of the inner rolling surface 8a are formed, and the thickness thereof is set to be substantially uniform. ing. Here, since the shoulder portion 13 becomes a seal land surface of the outer seal 11 and a fitting surface of the inner seal 12, the shoulder portion 13 is formed with a predetermined size and accuracy by grinding after the rolling. The large end surface 8b and the small end surface 8c, which are likely to generate burrs in rolling processing, are turned after processing. Moreover, a grinding process is given as needed.

  Thus, in this embodiment, since the inner ring 8 is formed by cold rolling from the pipe material, the productivity is improved, the yield is good, the cost can be reduced, and the inner rolling surface 8a Since the shoulder portion 13 is formed by grinding, it is possible to ensure the same accuracy and sealing performance as a conventional bearing. Here, the inner ring 8 is formed by a cold rolling process. However, the inner ring 8 is not limited to this and may be formed by a warm rolling process. The surface may be formed by grinding.

  Here, as shown in an enlarged view in FIG. 3, the wall thickness of the large end portion of the inner ring 8 on the outer side is formed thinner than that of the conventional inner ring, and the action line L of the contact angle α intersects with the hub ring 1. In the position, the inner ring 8 and the hub ring 1 are not in contact with each other, and a gap is secured between the hub ring 1. On the other hand, the corner B of the hub wheel 1 is composed of a composite R composed of radii of curvature Rb and Rc.

  As shown in FIG. 4A, the inner ring 8 has a center position of the curvature radius Rw of the ball 10 (or a curvature radius of the inner rolling surface 8a) and a center position of the curvature radius Ri of the inner diameter portion 18 at the large end. Are set to be substantially the same position. As a result, the thickness of the inner ring 8 can be set to be substantially uniform, and the degree of freedom in designing the shape and dimensions of the corner B of the hub ring 1 to be described below is increased, and the strength and durability of the hub ring 1 are increased. Can be improved.

  As shown in FIG. 4 (b), the corner B of the hub wheel 1 is composed of a composite R composed of curvature radii Rb and Rc, and the curvature radius Rb on the shoulder 1a side has the corner R as a single R. In this case, it is set smaller than the maximum curvature radius Ra. Further, the curvature radius Rc on the small diameter step portion 1b side is set larger than the maximum curvature radius Ra when the corner R is a single R (Rb <Ra <Rc), and this curvature radius Rc is 2 of the curvature radius Rb. It is set to be twice or more (Rc ≧ 2 × Rb).

  Further, the corner B is composed of the composite R and the tangent line 19 that smoothly connects the composite R, and the axial dimension La of the corner B is set to be 1.5 times or more the radial dimension Lr. (La ≧ 1.5 × Lr). As a result, even if a large moment load is applied to the hub wheel 1 via the wheel mounting flange 5 when the vehicle turns, the stress generated in the corner B is suppressed, and the hub wheel 1 is reduced in weight and size. It is possible to provide a wheel bearing device that is improved in strength and durability.

  FIG. 5 is a longitudinal sectional view showing a second embodiment of the wheel bearing device according to the present invention. In this embodiment, the above-described embodiment (FIG. 1) is applied to a driven wheel, and other parts and parts having the same parts or the same functions as those of the above-described embodiments are denoted by the same reference numerals and detailed. Description is omitted.

  This wheel bearing device has a second generation structure on the driven wheel side, and includes a hub wheel 20 and a wheel bearing 21 attached to the hub wheel 20. The hub wheel 20 has a wheel mounting flange 5 at an end portion on the outer side, and a small-diameter step portion 1b extending in the axial direction from the wheel mounting flange 5 via a shoulder portion 1a is formed on the outer periphery. The wheel bearing 21 is press-fitted into the small-diameter step portion 1b through a predetermined squeeze, and the bearing preload is applied by the crimping portion 20a formed by plastic deformation of the end portion of the small-diameter step portion 1b in the axial direction. It is fixed to. The hub wheel 20 is formed of medium and high carbon steel containing 0.40 to 0.80 wt% of carbon such as S53C, and the surface hardness is set to a range of 50 to 64 HRC by induction hardening from the shoulder portion 1a to the small diameter step portion 1b. A hardened layer 24 is formed (indicated by cross hatching in the lower half of the figure). The caulking portion 20a is kept in the structure and hardness after forging.

  The wheel bearing 21 integrally has a vehicle body mounting flange 22a to be attached to a knuckle (not shown) on the outer periphery, and double-row arc-shaped outer rolling surfaces 7a and 7a are integrally formed on the inner periphery. The outer member 22, the inner ring 8, 23 in which arc-shaped inner rolling surfaces 8 a, 8 a facing the double row outer rolling surfaces 7 a, 7 a are formed on the outer periphery, and a cage between both rolling surfaces 9 and 9 and the double rows of balls 10 and 10 accommodated so as to roll freely, and the seals 12 and 12 attached to the opening of the annular space formed between the outer member 22 and the inner ring 8; It has.

  The outer member 22 is formed of medium-high carbon steel containing 0.40 to 0.80 wt% of carbon such as S53C, and the double row outer rolling surfaces 7a and 7a have a surface hardness in the range of 54 to 64HRC by induction hardening. A hardened layer 26 is formed (indicated by cross hatching in the lower half of the figure). On the other hand, the inner ring 23 is made of a high carbon chrome bearing steel such as SUJ2, and is hardened in the range of 54 to 64 HRC up to the core by quenching.

  The corner portion B of the hub wheel 20 is composed of a composite R composed of the curvature radii Rb and Rc, as in the above-described embodiment, and the curvature radius Rc on the small diameter step portion 1b side is larger than the curvature radius Rb on the shoulder portion 1a side. It is set to be twice or more (Rc ≧ 2 × Rb). Further, the composite R and the tangent line 19 that smoothly connects the composite R are formed, and the axial dimension La of the corner B is set to be 1.5 times or more of the radial dimension Lr (La ≧ 1. 5 × Lr). As a result, even if a large moment load is applied to the hub wheel 20 during turning of the vehicle, the stress generated at the corner B is suppressed, and the weight and size are reduced, and the strength and durability of the hub wheel 20 are improved. Can be planned.

  Here, a mortar-shaped recess 25 extending in the axial direction is formed at the outer side end of the hub wheel 20. The recess 25 is formed by forging, and its depth is at least up to the vicinity of the ball 10 on the outer side, and is formed so that the thickness on the outer side of the hub wheel 20 is substantially uniform.

  As described above, in the present embodiment, the thickness of the large end portion of the inner ring 8 on the outer side is formed thinner than that of the conventional inner ring, and at the position where the line of action L of the contact angle α intersects the hub ring 20, Since a clearance is secured between the wheel 20 and a mortar-shaped recess 25 is formed at the outer end of the hub wheel 20, the thickness of the outer side of the hub wheel 20 can be made uniform. The minimum wall thickness t can be increased as compared with a hub ring having R as a single R. Therefore, even when a large moment load is applied to the hub wheel 20, the stress generated at the corner B can be suppressed, the weight and size can be reduced, and the strength and durability of the hub wheel 20 can be improved.

  The embodiment of the present invention has been described above, but the present invention is not limited to such an embodiment, and is merely an example, and various modifications can be made without departing from the scope of the present invention. Of course, the scope of the present invention is indicated by the description of the scope of claims, and further, the equivalent meanings described in the scope of claims and all modifications within the scope of the scope of the present invention are included. Including.

  The wheel bearing device according to the present invention is for a wheel of a first generation or a second generation structure including a hub ring integrally having a wheel mounting flange at one end and a pair of inner rings fitted and fixed to the hub ring. Applicable to bearing devices.

It is a longitudinal section showing a 1st embodiment of a bearing device for wheels concerning the present invention. It is a longitudinal cross-sectional view which shows the wheel bearing of FIG. It is a principal part enlarged view of FIG. (A) is a principal part enlarged view of the inner ring single-piece | unit of FIG. (B) is a principal part enlarged view of the hub wheel single-piece | unit of FIG. It is a longitudinal cross-sectional view which shows 2nd Embodiment of the wheel bearing apparatus which concerns on this invention. It is a principal part enlarged view which shows the conventional wheel bearing apparatus.

Explanation of symbols

1, 20 ... hub wheel 1a, 13, 16 ... shoulder 1b ... Small diameter step 1c, 17a ... Serration 2, 21 ... Wheel bearing 3 ...・ ・ ・ ・ Constant velocity universal joint 4 ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ Fixing nut 5 ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ Wheel mounting flange 5a ・ ・・ ・ ・ ・ ・ ・ ・ ・ Hub bolt 6 ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ Knuckle 7, 22 ・ ・ ・ ・ ・ ・ ・ ・ Outside Member 7a ... Outer rolling surface 8, 23 ... Inner ring 8a ... .... Inner rolling surface 8b ......... Large end face 8c ...・ ・ ・ ・ ・ Small end face 9 ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ Retainer 10 ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ Ball 11, 12, ... Seal 14 ... Outer joint member 15 ... Mouse part 17 ...・ ・ ・ ・ ・ ・ ・ ・ ・ Shaft 17b ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ Male thread 18 ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ Lar end of inner ring Inner diameter part 19 ... tangent line 20a ... caulking part 22a ... .... Body mounting flanges 24, 26 .... Hardened layer 25 ... ...・ ・ ・ ・ ・ ・ ・ ・ Hub wheel 52 ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ Shoulder 53 ・ ・ ・ ・ ・ ・ ・ ・.... Small diameter step 54 ... Inner ring 55 ... Large end face 56 ...・ ・ ・ ・ ・ ・ ・ ・ Chamfer A, B ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ Corner a, b, c ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ Corner of hub wheel Radius of curvature of the part L ... contact line La of the contact angle ...・ ・ ・ ・ ・ ・ ・ ・ ・ Radial dimensions Ra, Rb, Rc of corners ・ ・ ・ ・ ・ ・ ・ ・ Curve radius of curvature Ri ・ ・ ・ ・ ・ ・ ・ ・.... curvature radius Rw of the inner diameter at the large end of the inner ring ......... curvature radius t of the ball ... ... Minimum wall thickness X at the corners of the hub wheel ... ........ contact angle

Claims (6)

A hub wheel integrally having a wheel mounting flange for mounting a wheel on one end, and a small-diameter step portion extending in the axial direction from the wheel mounting flange via a shoulder; and
A wheel bearing that is press-fitted into the small-diameter step portion of the hub wheel via a predetermined scissors,
This wheel bearing is an outer member in which a double row arc-shaped outer rolling surface is integrally formed on the inner periphery,
A pair of inner rings each having an arcuate inner rolling surface facing the double row outer rolling surface on the outer periphery;
A double row of balls accommodated between both rolling surfaces of the inner ring and the outer member;
A seal attached to an opening of an annular space formed between the outer member and the inner ring,
In the wheel bearing device in which the small end surfaces of the pair of inner rings collide in a butted state to constitute a back-to-back type double row angular contact ball bearing,
Of the pair of inner rings, at least the inner ring on the outer side is formed with a shoulder portion extending in the axial direction from the large diameter side of the inner rolling surface, the wall thickness is set substantially uniformly over the entire width, and The position where the center position of the radius of curvature of the inner diameter portion of the inner end of the inner ring and the center position of the radius of curvature of the ball are set to substantially the same position, and the line of action of the contact angle of the inner ring intersects the hub ring The wheel bearing device is characterized in that the inner ring and the hub ring are not in contact with each other and a gap is secured.   The wheel bearing device according to claim 1, wherein the inner ring on the outer side is formed from a pipe material by cold rolling.   The corner portion of the shoulder portion of the hub wheel and the small-diameter step portion is composed of a composite R composed of curvature radii Rb and Rc, and the curvature radius Rb on the shoulder portion side has the corner R as a single R. The radius of curvature Rc is set to be smaller than the maximum radius of curvature Ra in this case, and the radius of curvature Rc on the small diameter step portion side is set to be larger than the radius of curvature Ra and Rc> Ra. Wheel bearing device.   A corner portion of the shoulder portion of the hub wheel and the small-diameter step portion is constituted by a composite R having curvature radii Rb and Rc and a tangent line smoothly connecting the composite R, and an outer side end portion of the hub wheel. The wheel bearing device according to claim 3, wherein a mortar-shaped recess extending in the axial direction is formed by forging and the thickness of the corner is set to be substantially uniform.   The wheel bearing device according to claim 3 or 4, wherein the curvature radius Rc is set to be twice or more of the curvature radius Rb.   The wheel bearing device according to any one of claims 3 to 5, wherein an axial dimension La of a corner portion of the hub wheel is set to 1.5 times or more of a radial dimension Lr.

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