JP2013091404A - Wheel bearing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a wheel bearing device in which weight reduction and size reduction are achieved while strength and rigidity are secured, and in which costs are reduced.SOLUTION: The wheel bearing device includes a plurality of wheel mounting arms 6 which are formed so that a wheel mounting flange is radially protruded from an annular base 6d. Hub bolt insertion-holes 6b are formed at the circumference of the wheel mounting arms 6. The wheel mounting arms 6 are formed to be notched other than in section near the hub bolt insertion-holes 6b with almost the same as widths of the sections where the respective hub bolt insertion-holes 6b are formed. Ribs 11 are formed by forging to internally protrude along both edges of the wheel mounting arms 6.

Description

  The present invention relates to a wheel bearing device that rotatably supports a wheel of an automobile or the like with respect to a suspension device, and more particularly, to a wheel bearing device that achieves a reduction in cost while reducing the weight and size of the device.

  In recent years, demands for improving fuel efficiency have been severe from the viewpoint of resource saving or environmental performance. In automobile parts, the weight reduction of wheel bearing devices has been attracting attention as a factor to meet such demands and has been strongly desired for a long time. In particular, light vehicles such as light four-wheel vehicles or small cars among vehicles such as automobiles have been increasingly demanded for weight reduction. There have been various proposals related to wheel bearing devices that have been reduced in weight, and at the same time, increasing rigidity and cost are also important factors.

  FIG. 7 shows an example of a wheel bearing device that is used in an automobile and is reduced in weight. This wheel bearing device has a typical structure used for a driven wheel, and includes an inner member 51 and an outer member 52, and a double row of balls 53 accommodated between the members 51 and 52 so as to roll freely. 53. Here, the inner member 51 refers to a hub ring 54 and an inner ring 55 press-fitted into the hub ring 54.

  The hub wheel 54 integrally has a wheel mounting flange (hereinafter referred to as a wheel mounting arm) 56 that is divided into four radially extending at one end of the outer periphery, and the wheel mounting arm 56 is located at a circumferentially equidistant position. Has a hub bolt 56a for fastening the wheel. The wheel mounting arm 56 is formed by notching a portion excluding the vicinity of the hub bolt insertion hole 56b and projecting radially from the annular base portion, that is, the brake pilot portion 56c with substantially the same width as the formation portion of each hub bolt insertion hole 56b. Has been.

  On the outer periphery of the hub wheel 54, one inner rolling surface 54a and a small-diameter step portion 54b extending in the axial direction from the inner rolling surface 54a are formed, and the inner ring 55 is inserted into the small-diameter step portion 54b via a predetermined shimiro. It is press-fitted. On the outer periphery of the inner ring 55, the other inner rolling surface 55a is formed. And the crimping part 54c is formed by carrying out the plastic deformation of the edge part of the small diameter step part 54b to radial direction outward. The inner ring 55 is fixed to the hub ring 54 in the axial direction by the caulking portion 54c.

  On the inner periphery of the outer member 52, double-row outer rolling surfaces 52a, 52a are formed opposite to the double-row inner rolling surfaces 54a, 55a of the inner member 51. Both the rolling surfaces 52a, 54a are formed. And double-row balls 53, 53 are accommodated in a freely rollable manner via a cage 57 between 52a, 55a. A seal 58 is attached to the end of the outer member 52 to seal the opening of the annular space formed between the outer member 52 and the inner member 51.

  Further, the outer member 52 integrally has a vehicle body mounting flange 52b attached to a knuckle (not shown) constituting a suspension device on the outer periphery, and a plurality of bolt insertion holes 59 are formed on the outer periphery of the vehicle body mounting flange 52b. It has been drilled. The vehicle body mounting flange 52b is formed in a shape in which a portion excluding the vicinity of the bolt insertion hole 59 is cut out of the outer peripheral portion, and only the formation portion of each bolt insertion hole 59 projects radially outward.

  That is, the vehicle body mounting flange 52b is divided into a plurality of partial flanges 60 that are separated in the circumferential direction. Then, it is fixed to the knuckle by a knuckle bolt (not shown) that penetrates the bolt insertion hole 59. Further, a cylindrical knuckle pilot portion 52c extending in the axial direction from the vehicle body mounting flange 52b is formed at the end of the outer member 52, and a knuckle is fitted to the outer diameter surface of the knuckle pilot portion 52c.

  A chamfered portion 61 having a predetermined radius of curvature r is formed at both ends of the outer periphery of the wheel mounting arm 56 by a forging process, and the chamfered portion 61 has an axial dimension L of 1 to 5 mm, preferably 2 to 2. The range is set to 4 mm. That is, since the side surface 56d of the wheel mounting arm 56 is usually scraped off by about 1 mm by turning, the axial dimension L is required to be at least 1 mm, and if the axial dimension L becomes too large, the outer peripheral surface of the wheel mounting arm 56 Therefore, the upper limit is set to 5 mm.

  As shown in FIG. 8, in the hub wheel 54 manufactured in the forging process, the outer side surface 56d of the wheel mounting arm 56 including the outer peripheral surface is formed in a desired shape and size in the turning process. At this time, since the chamfered portions 65 are formed at both ends of the outer periphery, burrs are generated at the outer peripheral edge of the side surface 56d, and the side surface 56d is not curled up. Therefore, it is not necessary to remove burrs on the side surface 56d of the wheel mounting arm 56, and the cost can be reduced by reducing the number of man-hours (for example, see Patent Document 1).

JP 2007-145203 A

  In such a conventional wheel bearing device, the hub wheel 54 is reduced in weight by forming the wheel mounting flange into a flower shape formed of the wheel mounting arms 56 divided into four radially extending portions. -The flange thickness must be increased to compensate for the lack of rigidity. Because of this weight increase, there were still challenges to satisfy the three requirements of high rigidity, light weight, and cost reduction.

  The present invention has been made in view of such a conventional problem, and an object thereof is to provide a wheel bearing device that achieves light weight and compactness while ensuring strength and rigidity and at the same time lowers the cost. To do.

  In order to achieve such an object, the invention according to claim 1 of the present invention includes an outer member in which a double row outer rolling surface is integrally formed on the inner periphery, and a hub bolt at an end portion on the outer side. And a hub wheel integrally having a wheel mounting flange for mounting a wheel and having a small-diameter step portion extending in the axial direction on the outer periphery, and at least one inner ring press-fitted into the small-diameter step portion of the hub ring. An inner member in which a double-row inner rolling surface facing the double-row outer rolling surface is formed on the outer periphery, and a double-row rolling element housed so as to roll freely between the both rolling surfaces; In the wheel bearing device, the arm bottom portion is formed by projecting radially from the annular base portion of the wheel mounting flange, and a hub bolt insertion hole into which the hub bolt is press-fitted and fixed to the wheel mounting flange is circular. A plurality of holes are drilled in the circumferential position It is formed ribs projecting to the inner side along the edges of the arm base.

  Thus, in the wheel bearing device having the hub wheel integrally having the wheel mounting flange for mounting the wheel at one end, the arm bottom is formed by projecting radially from the annular base of the wheel mounting flange. At the bottom, a plurality of hub bolt insertion holes, in which hub bolts are press-fitted and fixed to the wheel mounting flange, are perforated at the circumferential position, and ribs are formed to protrude toward the inner side along both edges of the arm bottom. -It is possible to provide a wheel bearing device that achieves light weight and compactness while ensuring rigidity, and at a low cost.

  Preferably, as in the invention described in claim 2, if the ribs are integrally formed by forging, cost reduction can be achieved without increasing the number of processing steps.

  According to a third aspect of the present invention, the wheel mounting flange includes a wheel mounting arm in which the wheel mounting flange is divided into a plurality of parts. The hub bolt insertion hole is formed in a circumferential position of the wheel mounting arm, and the wheel mounting flange is provided. The arm is cut out except for the vicinity of the hub bolt insertion hole, has a width substantially the same as that of each hub bolt insertion hole, and projects radially from the base, and the ribs are formed on both edges of the wheel mounting arm. If formed, the knuckle bolt can be easily fastened with a tightening tool or the like without being disturbed by the wheel mounting arm when the outer member is fastened to the knuckle, thus simplifying the assembly work. can do.

  According to a fourth aspect of the present invention, the wheel mounting arm is formed in an arc shape in which an outer diameter portion forms a part of a concentric circle with the bolt insertion hole, and from the both edges of the wheel mounting arm, If the rib is formed along the diameter portion, it is possible to further increase the strength and rigidity while reducing the weight and size.

  Further, as in the invention described in claim 5, the rib may be formed in a taper shape that gradually decreases from the base portion to the outer diameter portion instead of a fixed protrusion amount.

  Further, as in the invention described in claim 6, the rib may be formed on a curved surface in which the protrusion amount gradually decreases from the base portion to the outer diameter portion.

  According to a seventh aspect of the present invention, the wheel mounting flange is formed in a circular shape, and includes the arm bottom and a substantially fan-shaped flange bottom formed between the arm bottoms. If the ribs are formed along both edges and the outer diameter portion of the flange bottom, the strength and rigidity can be further increased while reducing the weight.

  Further, as in the invention according to claim 8, the wheel mounting flange is formed in a structure in which the flange bottom portion is cut off, and the rib is formed on both edges of the arm bottom portion and an outer diameter portion between the arm bottom portions. If formed, it is possible to further reduce the weight while securing the strength and rigidity.

  Further, as in the ninth aspect of the invention, the hub wheel is made of medium-high carbon steel containing carbon of 0.40 to 0.80 wt%, and is surface hardened by induction hardening from the base portion to the small diameter step portion. Is hardened in the range of 58 to 64 HRC, the strength and rigidity of the hub ring can be secured, and the fretting wear of the fitting surface with the inner ring can be prevented, and the durability of the hub ring 4 is improved. To do.

  According to a tenth aspect of the present invention, the outer member integrally has a vehicle body attachment flange attached to a knuckle constituting a suspension device on the outer periphery, and a plurality of bolts are provided on the outer periphery of the vehicle attachment flange. A plurality of through holes are formed, and the vehicle body mounting flange is formed by cutting out a portion of the outer peripheral portion excluding the vicinity of the bolt insertion holes, and only the portions where the bolt insertion holes are formed protrude radially. If it is divided into the partial flanges, weight reduction can be achieved without impairing the strength and rigidity of the outer member.

  The wheel bearing device according to the present invention includes an outer member in which a double row outer rolling surface is integrally formed on the inner periphery, and a wheel mounting flange for mounting the wheel to the outer end via a hub bolt. A hub wheel integrally formed and having a small-diameter step portion extending in the axial direction on the outer periphery, and at least one inner ring press-fitted into the small-diameter step portion of the hub wheel, and outer rolling of the double row on the outer periphery. In a wheel bearing device comprising: an inner member in which a double-row inner rolling surface facing the surface is formed; and a double-row rolling element that is slidably accommodated between the both rolling surfaces; An arm bottom is formed by projecting radially from the annular base of the wheel mounting flange, and a plurality of hub bolt insertion holes into which the hub bolt is press-fitted and fixed to the wheel mounting flange are formed in a circumferential position on the arm bottom. Along both edges of the bottom of the arm Since the ribs projecting to the inner side are formed, while ensuring the strength and rigidity with reduced weight and compact, it is possible to provide a wheel bearing apparatus which attained cost.

It is a longitudinal section showing one embodiment of a wheel bearing device concerning the present invention. (A) is a longitudinal cross-sectional view which shows the hub wheel single-piece | unit of FIG. 1, (b) is a front view of (a), (c) is sectional drawing along the II-II line of (b). (A) is a front view which shows the modification of FIG. 2, (b) is sectional drawing along the III-III line of (a). (A) is a fragmentary sectional view which shows the other modification of FIG. 2, (b) is a fragmentary sectional view which shows the modification of (a). (A) is a front view which shows the other modification of FIG. 2, (b) is sectional drawing along the VV line of (a). (A) is a front view which shows the modification of FIG. 5, (b) is sectional drawing along the VI-VI line of (a). It is a longitudinal cross-sectional view which shows the conventional wheel bearing apparatus. (A) is a front view which shows the hub ring single-piece | unit of FIG. 7, (b) is sectional drawing along the VIII-VIII line of (a).

  An outer member integrally having a vehicle body mounting flange to be attached to a knuckle constituting a suspension device on the outer periphery, a double row outer rolling surface formed integrally on the inner periphery, and a hub bolt at the outer end A wheel mounting flange for mounting a wheel via the inner rolling surface, and an inner rolling surface facing one of the double row outer rolling surfaces on the outer periphery, and a small diameter step extending in the axial direction from the inner rolling surface An inner member comprising a hub ring formed with a portion, and an inner ring press-fitted into a small-diameter step portion of the hub ring and having an inner rolling surface facing the other of the outer rolling surfaces of the double row on the outer periphery. In the wheel bearing device including the inner member and the double row rolling elements that are slidably accommodated between both rolling surfaces of the outer member, the wheel mounting flange is radially formed from an annular base. Consists of a plurality of protruding wheel mounting arms. The hub bolt insertion hole is drilled in the circumferential position of the wheel mounting arm, and the wheel mounting arm is cut out at a portion other than the vicinity of the hub bolt insertion hole so that it has substantially the same width as the formation portion of each hub bolt insertion hole. The ribs are formed by forging so as to protrude toward the inner side along both edges of the wheel mounting arm.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
FIG. 1 is a longitudinal sectional view showing an embodiment of a wheel bearing device according to the present invention, FIG. 2 (a) is a longitudinal sectional view showing a single hub wheel of FIG. 1, and FIG. FIG. 3C is a cross-sectional view taken along line II-II in FIG. 3B, FIG. 3A is a front view showing a modification of FIG. 2, and FIG. 4A is a partial sectional view showing another modification of FIG. 2, FIG. 4B is a partial sectional view showing a modification of FIG. 2, and FIG. FIG. 6A is a front view showing another modification of FIG. 2, FIG. 6B is a cross-sectional view taken along line VV of FIG. 6A, and FIG. 6A is a front view showing the modification of FIG. (B) is sectional drawing along the VI-VI line of (a). 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 is referred to as a third generation for rotatably supporting the driven wheel, and is composed of a double row of the inner member 1, the outer member 2, and the two members 1 and 2 accommodated so as to roll freely. Rolling elements (balls) 3 and 3 are provided. Here, the inner member 1 indicates a hub ring 4 and an inner ring 5 press-fitted into the hub ring 4.

  The hub wheel 4 integrally has a wheel mounting flange (hereinafter referred to as a wheel mounting arm) 6 divided into a plurality of pieces (here, divided into five) extending radially on the outer periphery of the outer end. The hub bolt 6a for fastening a wheel (not shown) is planted at the circumferential position. The wheel mounting arm 6 is cut out at a portion other than the vicinity of the hub bolt insertion hole 6b and has a width substantially the same as the portion where each hub bolt insertion hole 6b is formed. Is formed to protrude. Thus, when the outer member 2 is fastened to the knuckle, the knuckle bolt (not shown) can be easily fastened with a tightening tool or the like without being obstructed by the wheel mounting arm 6. Work can be simplified.

  On the outer periphery of the hub wheel 4, one (outer side) inner rolling surface 4a and a small-diameter step portion 4b extending in the axial direction from the inner rolling surface 4a are formed, and an inner ring 5 is predetermined on the small-diameter step portion 4b. It is press-fitted through a shimeshiro. On the other hand, the other (inner side) inner rolling surface 5 a is formed on the outer periphery of the inner ring 5. The end portion of the small diameter step portion 4b is plastically deformed radially outward to form a crimped portion 4c. The inner ring 5 is applied to the hub wheel 4 in a state where a predetermined bearing preload is applied by the crimped portion 4c. On the other hand, it is fixed in the axial direction.

  As a result, the hub wheel 4 can be reduced in weight and size while ensuring the strength and rigidity of the hub wheel 4. Moreover, since it is not necessary to control the preload amount by tightening the inner ring firmly with a nut or the like as in the prior art, it is possible to simplify the incorporation into the vehicle and maintain the preload amount for a long time. In addition, the number of parts can be greatly reduced, and the cost can be reduced in combination with the improvement of the incorporation. The wheel bearing according to the present invention is not limited to the illustrated third generation structure. For example, although not illustrated, the first or second generation structure in which a pair of inner rings are press-fitted into the small-diameter step portion of the hub wheel. It may be.

  On the inner periphery of the outer member 2, double-row outer rolling surfaces 2a, 2a facing the double-row inner rolling surfaces 4a, 5a of the inner member 1 are integrally formed, and both the rolling surfaces 2a are formed. Double-row rolling elements 3 and 3 are accommodated between 4a and 2a and 5a via a cage 7 so as to roll freely.

  Further, a seal 8 is attached to the outer end of the outer member 2 to seal the opening of the annular space formed between the outer member 2 and the inner member 1. On the other hand, a cup-shaped seal cap (not shown) is attached to the inner end of the outer member 2 to close the opening of the outer member 2. The seal 8 and the seal cap prevent leakage of lubricating grease sealed inside the bearing and intrusion of rainwater, dust, and the like from the outside into the bearing.

  Further, the outer member 2 integrally has a vehicle body mounting flange 2b attached to a knuckle (not shown) constituting a suspension device on the outer periphery, and a plurality of bolt insertion holes 9 are formed on the outer periphery of the vehicle body mounting flange 2b. It has been drilled. The vehicle body mounting flange 2b is formed in a shape in which a portion excluding the vicinity of the bolt insertion hole 9 in the outer peripheral portion thereof is cut out, and only a portion where each bolt insertion hole 9 is formed projects radially to the outer diameter side. That is, the vehicle body mounting flange 2b is divided into a plurality of partial flanges 10 separated in the circumferential direction. Then, it is fixed to the knuckle by a knuckle bolt that penetrates the bolt insertion hole 9. Further, a cylindrical knuckle pilot portion 2c extending in the axial direction from the vehicle body mounting flange 2b is formed at the inner end of the outer member 2, and the knuckle is fitted to the outer diameter surface of the knuckle pilot portion 2c. Is done.

  Thus, the outer member 2 is formed with the vehicle body mounting flange 2b composed of a plurality of partial flanges 10 extending radially on the outer periphery, so that weight reduction can be achieved without impairing the strength and rigidity of the outer member 2. be able to. The knuckle pilot portion 2c may be provided with notches at a plurality of locations in the circumferential direction, and may be intermittently formed in a protruding piece shape. Thereby, further weight reduction can be achieved without reducing the rigidity of the outer member 2.

  The hub wheel 4 is made 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 58 by induction hardening from the inner side base portion 6d of the wheel mounting arm 6 to the small diameter step portion 4b. Cured to a range of ~ 64 HRC. The caulking portion 4c is an unquenched portion having a surface hardness of 25HRC or less after forging. As a result, the strength and rigidity of the hub wheel 4 can be secured, and fretting wear of the fitting surface with the inner ring 5 can be prevented, and the durability of the hub wheel 4 is improved. In addition, workability when the caulking portion 4c is plastically deformed can be improved, and generation of cracks or the like during processing can be prevented to improve quality reliability.

  The outer member 2 is formed of medium and high carbon steel containing carbon of 0.40 to 0.80 wt%, such as S53C, like the hub wheel 4, and at least the double-row outer raceway surfaces 2a and 2a are hardened by induction hardening. The thickness is cured in the range of 58 to 64 HRC. On the other hand, the inner ring 5 and the rolling element 3 are made of high carbon chrome bearing steel such as SUJ2, and are hardened in the range of 58 to 64 HRC to the core part by quenching. In addition, although the wheel bearing apparatus comprised by the double row angular contact ball bearing which used the rolling elements 3 and 3 as a ball | bowl was illustrated here, it is not restricted to this, It is a double row tapered roller bearing which uses a tapered roller for a rolling element. It may be configured.

  Here, in this embodiment, as shown in FIG. 2, the wheel mounting arm 6 of the hub wheel 4 is formed by forging into a substantially U-shaped cross section. Specifically, a rib 11 is formed from the base portion 6 d of the wheel mounting arm 6 to the outer diameter portion. That is, the wheel mounting arm 6 includes an arm bottom 12 having a bolt insertion hole 9 and a rib 11 formed so as to protrude toward the inner side along both edges of the arm bottom 12. As a result, it is possible to provide a wheel bearing device that achieves light weight and compactness while ensuring strength and rigidity, and at a low cost without increasing the number of processing steps.

  FIG. 3 shows a modification of the hub wheel 4 described above. In addition, the same code | symbol is attached | subjected to the component and site | part which has the same component same part as embodiment mentioned above, or the same function, and detailed description is abbreviate | omitted. The hub wheel 13 integrally has a wheel mounting arm 14 divided into five radially extending on the outer periphery of the outer end, and a hub bolt (not shown) is planted at a circumferential position of the wheel mounting arm 14. A bolt insertion hole 6b is provided. As in the above-described embodiment, the wheel mounting arm 14 is cut out at a portion other than the vicinity of the hub bolt insertion hole 6b, and has a width substantially the same as that of each hub bolt insertion hole 6b and protrudes radially from the annular base portion 6d. Is formed.

  The wheel mounting arm 14 is formed in an arc shape whose outer diameter portion forms a part of a concentric circle with the bolt insertion hole 9, and the arm bottom portion 15 having the bolt insertion hole 9 and both edges and the outer diameter portion of the arm bottom portion 15. A rib 16 is formed so as to protrude along the inner side along the line. Thereby, intensity | strength and rigidity can be raised further, achieving weight reduction and compactness.

  As shown in FIG. 4 (a), the rib 17 may be a wheel mounting arm 18 formed in a tapered shape that gradually decreases from the base portion 6d to the outer diameter portion instead of a constant protrusion amount, As shown in (b), the rib 19 may be a wheel mounting arm 20 formed on a curved surface where the protruding amount gradually decreases from the base portion 6d to the outer diameter portion.

  FIG. 5 shows another modification of the hub wheel 4 described above. The hub wheel 21 integrally has a circular wheel mounting flange 22 on the outer periphery of the outer end, and a bolt insertion hole 6b in which a hub bolt (not shown) is implanted at a circumferential position of the wheel mounting flange 22. Is drilled.

  The wheel mounting flange 22 has substantially the same width as the formation portion of the hub bolt insertion hole 6b, and has an arm bottom portion 23 formed radially projecting from the annular base portion 6d, and a substantially fan-shaped portion formed between the arm bottom portions 23. The flange bottom portion 24 and ribs 25 formed so as to protrude toward the inner side along both edges of the arm bottom portion 23 and the outer diameter portion of the flange bottom portion 24 are configured. Thereby, intensity | strength and rigidity can be raised further, aiming at weight reduction.

  FIG. 6 shows a modified example of the hub wheel 21 described above. The hub wheel 26 integrally has a circular wheel mounting flange 27 on the outer periphery of the outer end, and a bolt insertion hole 6b in which a hub bolt (not shown) is implanted at a circumferential position of the wheel mounting flange 27. Is drilled.

  The wheel mounting flange 27 is formed in a structure in which the flange bottom portion 24 portion that is substantially fan-shaped of the wheel mounting flange 22 is cut out. That is, the wheel mounting flange 27 has substantially the same width as the portion where the hub bolt insertion hole 6b is formed, and protrudes radially from the annular base portion 6d, and between the both edges of the arm bottom portion 23 and the arm bottom portion 23. The rib 25 is formed so as to protrude toward the inner side along the outer diameter portion. Thereby, further weight reduction can be achieved while securing strength and rigidity.

  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 can be applied to a wheel bearing device provided with a hub wheel integrally having a wheel mounting flange, regardless of whether it is for a driving wheel or a driven wheel.

DESCRIPTION OF SYMBOLS 1 Inner member 2 Outer member 2b Car body mounting flange 2c Knuckle pilot part 3 Rolling elements 4, 13, 21, 26 Hub wheel 4a, 5a Inner rolling surface 4b Small diameter step part 4c Clamping part 5 Inner rings 6, 14, 18 , 20 Wheel mounting arm 6a Hub bolt 6b Hub bolt insertion hole 6c Brake pilot part 6d Base 7 Cage 8 Seal 9 Bolt insertion hole 10 Partial flange 11, 16, 17, 19, 25 Rib 12, 15, 23 Arm bottom part 22, 27 Wheel Mounting flange 24 Flange bottom 51 Inner member 52 Outer member 52b Car body mounting flange 52c Knuckle pilot portion 53 Ball 54 Hub wheel 54a, 55a Inner rolling surface 54b Small diameter step portion 54c Clamping portion 55 Inner ring 56 Wheel mounting arm 56a Hub bolt 56b Hub bolt insertion hole 56c Brake pilot part 56d Side surface 57 Vessel 58 seals 59 bolt insertion hole 60 portion flange 61 the radius of curvature of the axial dimension r chamfer of the chamfered portion L chamfer

Claims (10)

An outer member in which a double row outer rolling surface is integrally formed on the inner periphery;
A hub wheel having a wheel mounting flange for mounting a wheel via a hub bolt on the outer side end and having a small-diameter step portion extending in the axial direction on the outer periphery, and press-fitting into the small-diameter step portion of this hub ring An inner member formed of at least one inner ring formed with a double-row inner rolling surface facing the double-row outer rolling surface on the outer periphery;
In the wheel bearing device comprising a double-row rolling element accommodated between the rolling surfaces so as to roll freely,
An arm bottom is formed by projecting radially from the annular base of the wheel mounting flange, and a plurality of hub bolt insertion holes into which the hub bolt is press-fitted and fixed to the wheel mounting flange are formed at circumferential positions on the arm bottom. The wheel bearing device is characterized in that ribs are formed so as to protrude toward the inner side along both edges of the arm bottom.   The wheel bearing device according to claim 1, wherein the rib is integrally formed by forging.   The wheel mounting flange comprises a wheel mounting arm divided into a plurality of parts, and the hub bolt insertion hole is formed at a circumferential position of the wheel mounting arm, and the wheel mounting arm is a portion excluding the vicinity of the hub bolt insertion hole. The said rib is formed in the both edges of the said wheel attachment arm, and it is formed so that it may protrude from the said base radially with the substantially same width as the formation part of each hub bolt insertion hole. Wheel bearing device.   The wheel mounting arm is formed in an arc shape in which an outer diameter portion forms a part of a concentric circle with the bolt insertion hole, and the rib is formed from both edges of the wheel mounting arm along the outer diameter portion. Item 4. The wheel bearing device according to Item 3.   The wheel bearing device according to any one of claims 1 to 4, wherein the rib is formed in a tapered shape that gradually decreases from the base portion toward the outer diameter portion instead of a fixed protrusion amount.   The wheel bearing device according to any one of claims 1 to 4, wherein the rib is formed on a curved surface in which a protruding amount gradually decreases from the base portion to the outer diameter portion.   The wheel mounting flange is formed in a circular shape, and includes the arm bottom portion and a substantially fan-shaped flange bottom portion formed between the arm bottom portions, along both edges of the arm bottom portion and the outer diameter portion of the flange bottom portion. The wheel bearing device according to claim 1, wherein the rib is formed.   The wheel mounting flange according to claim 7, wherein the wheel mounting flange is formed in a structure in which the flange bottom portion is cut off, and the rib is formed on both edges of the arm bottom portion and an outer diameter portion between the arm bottom portions. Bearing device.   The hub ring is made of medium and high carbon steel containing 0.40 to 0.80 wt% of carbon, and is hardened by induction hardening from the base portion to the small diameter step portion in a range of 58 to 64 HRC. Item 2. A wheel bearing device according to Item 1.   The outer member integrally has a vehicle body mounting flange attached to a knuckle constituting a suspension device on the outer periphery, and a plurality of bolt insertion holes are formed in the outer peripheral portion of the vehicle body mounting flange. However, the part except the vicinity of the said bolt insertion hole is notched among outer peripheral parts, and only the formation part of each bolt insertion hole is divided | segmented into the some partial flange which protrudes radially on the outer diameter side. Wheel bearing device.

Images