JP2008296666A - Wheel bearing device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a wheel bearing device wherein a hub ring has improved strength and durability under rotated and bent conditions while a wheel mounting flange has a reduced weight without changing its shape and size and giving deterioration to its face run-out. <P>SOLUTION: The fourth-generation wheel bearing device comprises a stem part 16 pressed into the hub ring 1 via a predetermined interference, the hub ring 1 and the stem part 16 being welded and integrally joined to each other via a joint portion 23. Herein, a pitch circle diameter PCDi of six-row rolling elements on the inner side is larger than a pitch circle diameter PCDo on the outer side, and the number of the rolling elements 6 on the inner side is set to be greater than that on the outer side. The hub ring 1 is formed of medium carbon steel containing 0.40-0.80 wt.% carbon and subjected to tempering treatment so that the surface hardness is set to be 35 HRC or lower. An inside rolling surface 1a and a base 24 of the wheel mounting frame 7 are subjected to high frequency hardening to form a hardened layer 21 with its surface hardness in a range of 58-64 HRC. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a wheel bearing device in which wheels of a vehicle such as an automobile are rotatably supported with respect to a vehicle body, and more particularly to a wheel bearing device with improved strength and durability of a hub wheel under rotational bending conditions. It is.

  There are two types of wheel bearing devices for automobiles, one for a driven wheel and one for a drive wheel, and there are various types depending on the application. For example, the conventional wheel bearing for a drive wheel shown in FIG. In the apparatus, an inner member 50 having a hub wheel 51 and an inner ring 52, double-row rolling elements 53 and 54, an outer member 55, and a constant velocity universal joint that transmits engine power to the hub wheel 51. 56 is a main component. In the following description, the side closer to the outer side of the vehicle in a state assembled to the vehicle is referred to as the outer side (left side in the drawing), and the side closer to the center is referred to as the inner side (right side in the drawing).

  In such a wheel bearing device, the hub wheel 51 that supports the wheel (not shown) and the brake rotor 57 is used for a machine structure such as S53C in terms of easiness of forging, machinability, heat treatment, or economy. Medium carbon steel is used. The reduction of the size and weight of this type of wheel bearing device including this hub wheel 51 greatly contributes to the improvement of the fuel consumption and the running stability of the automobile, so that the wheel mounting flange 58 of the hub wheel 51 is ribbed. Thinning is progressing. However, the mechanical strength of the hub wheel 51 itself is approaching the fatigue limit of medium carbon steel, which is a material, and it is becoming difficult to achieve further reduction in size and weight.

  In particular, in the hub wheel 51 of this type of structure, when the wheel mounting flange 58 is thinned for weight reduction, the outer base portion, that is, the brake rotor mounting surface 59 is changed to the cylindrical pilot portion 60. Rotational bending stress concentrates on the extending corner 61, and countermeasures are required. Therefore, it is conceivable to reduce the generated stress by increasing the size of the corner 61, that is, the radius of curvature, but this causes a problem of interference with the brake rotor 57 attached to the wheel mounting flange 58. There is a limit to increasing the radius of curvature of the portion 61.

  Against such a background, the present applicant has already proposed a wheel bearing device capable of reducing the weight without changing the shape and dimensions of the wheel mounting flange 58 and increasing the strength of the hub wheel 51. Yes. In this wheel bearing device, as shown in FIG. 4, a hardened surface layer 62 is formed by induction hardening or the like at the corner 61 of the wheel mounting flange 58 of the hub wheel 51. Thereby, the corner | angular part 61 of the wheel mounting flange 58 used as the weakest part of rotation bending fatigue can be strengthened, and durability of the hub wheel 51 can be aimed at.

In addition to the seal land portion where the seal lip of the seal mounted on the outer side end portion of the outer member 55 (not shown) is slidably contacted, from the raceway surface to the respective portions a to d of the small diameter step portion. As a result, the hardened surface layer 63 is formed by induction hardening or the like. Furthermore, a hardened surface layer 65 is also formed on the serration portion 64 formed on the inner peripheral surface of the hub wheel 51. Such hardened surface layers 63 and 65 can improve the rotational bending fatigue strength, wear resistance, rolling fatigue life, and the like required in the respective parts a to d.
JP 2002-87008 A

  In such a conventional wheel bearing device, the surface hardening layer 62 is formed at the corner 61 of the wheel mounting flange 58 of the hub wheel 51, thereby reducing the weight without changing the shape and dimensions of the wheel mounting flange 58. However, the strength of the hub wheel 51 can be increased. However, in the induction hardening process for forming the surface hardened layer 62 at the corner 61, a heat treatment deformation occurs in the wheel mounting flange 58, resulting in a new problem that the runout of the brake rotor mounting surface 59 increases. This tendency is also attributed to the thinning of the wheel mounting flange 58. This surface runout affects the runout of the brake rotor 57 and induces brake judder, which may reduce the driving stability and drive feeling of the automobile. Here, a method of further turning the brake rotor mounting surface 59 after the heat treatment of the hub wheel 51 and correcting the deformation to improve the surface runout can be considered. However, the corner rotor 61 and the brake rotor mounting which is an unquenched portion can be considered. Since the surface 59 has a hardness difference, there is a kind of dilemma problem that a slight step is generated at the boundary between the corner 61 and the surface hardened layer 62.

  The present invention has been made in view of such circumstances, and without changing the shape and dimensions of the wheel mounting flange, and without deteriorating the surface runout, while reducing the weight while rotating and bending conditions An object of the present invention is to provide a wheel bearing device in which the strength and durability of the hub wheel are improved.

  In order to achieve such an object, the invention according to claim 1 of the present invention is a wheel bearing device in which a hub wheel, a double row rolling bearing and a constant velocity universal joint are unitized, and is a suspension device on the outer periphery. A vehicle body mounting flange for mounting is integrally formed, an outer member having a double row outer rolling surface formed on the inner periphery, a wheel mounting flange integrally formed at one end, and the double row on the outer periphery. One inner rolling surface facing the outer rolling surface, a hub wheel formed with a cylindrical small-diameter stepped portion extending in the axial direction from the inner rolling surface, and a stem portion fitted to the hub wheel. An inner member comprising an outer joint member of the constant velocity universal joint having an outer periphery and the other inner rolling surface facing the outer rolling surface of the double row, and the inner member and the outer A double row rolling element accommodated between both rolling surfaces of the member, and the outer member and the inner side In a wheel bearing device comprising a seal mounted in an opening of an annular space formed between the material and the material, the stem portion is press-fitted into the hub wheel via a predetermined shimeiro, and the hub wheel and stem The end of the fitting part of the part is integrally joined by a welded joint, and the hub wheel is formed of medium carbon steel containing 0.40 to 0.80% by weight of carbon to a predetermined surface hardness. A predetermined hardened layer is formed on the surface of the inner rolling base and the inner base of the wheel mounting flange which becomes the seal land portion of the seal by induction hardening.

  As described above, in the wheel bearing device of the fourth generation structure, the stem portion is press-fitted into the hub wheel via a predetermined shimiro, and the end portion of the fitting portion between the hub wheel and the stem portion is integrally formed by a welded joint portion. In addition to being bonded, the hub wheel is formed of medium carbon steel containing 0.40 to 0.80% by weight of carbon and tempered to a predetermined surface hardness to become the inner rolling surface and the seal land portion of the seal. Since the base of the inner side of the wheel mounting flange has a predetermined hardened layer formed by induction hardening, the shape and dimensions of the wheel mounting flange are not changed, and the current processing method and existing equipment remain unchanged. The strength and durability of the hub wheel can be increased, and since the hub wheel and the outer joint member are press-fitted and fixed, a load applied to the joint portion is small and a welding method with little heat influence can be employed. Therefore, the reliability of the joint portion between the hub wheel and the outer joint member can be improved.

  Preferably, when the surface hardness of the hub wheel after the tempering treatment is set to 35 HRC or less as in the invention described in claim 2, the workability of cutting and the like is improved and the heat treatment deformation is suppressed. can do. Moreover, the surface hardness of the bolt hole of the hub bolt that is press-fitted into the wheel mounting flange approaches the surface hardness of the hub bolt, so that when the hub bolt is press-fitted, it is possible to prevent the knar from being crushed and the fixing force from being reduced. The deformation of the brake rotor mounting surface can be prevented, and the surface runout causing the brake judder can be suppressed.

  Further, as in the invention described in claim 3, the joint portion is formed by laser welding that moves the light collecting unit in the circumferential direction along an end portion of the fitting portion between the hub wheel and the outer joint member. Thus, the thermal influence can be suppressed to the minimum, and the surface hardness can be prevented from being tempered due to the thermal influence on the bearing rolling surface and the carbon amount is 0.40 to 0.80 weight. %, It is possible to prevent the occurrence of burning cracks in the vicinity of the weld.

  Further, as in the invention described in claim 4, the outer joint member is formed of medium carbon steel containing 0.40 to 0.80% by weight of carbon such as S53C, and the inner rolling surface and the like. If a predetermined hardened layer is formed by induction hardening from the outer periphery of the shoulder portion to the stem portion, and the end portion of the stem portion is left as it is after forging, the strength and rigidity of the outer joint member is increased. This increases the durability and improves the durability, and because the welded stem part and the end of the fitting part of the hub wheel are unquenched parts with no hardened layer formed on the surface. Carbon is not precipitated and the welding strength can be further increased.

  Further, as in the invention according to claim 5, if the brake rotor mounting surface is turned after the hub bolt is press-fitted into the wheel mounting flange, the runout of the brake rotor mounting surface can be further improved. In addition, unlike the prior art, there is no risk of a step due to turning on the brake rotor mounting surface due to the difference in hardness from the hardened corner.

  Further, as in the invention described in claim 6, the pitch circle diameter of the inner side rolling element row of the double row rolling element rows is set larger than the pitch circle diameter of the outer side rolling element row. If the number of rolling elements on the inner side is set to be larger than the number of rolling elements on the outer side, the bearing space can be effectively utilized to reduce the weight and size of the device, and increase the bearing rigidity and the bearing. It is possible to extend the service life.

  A wheel bearing device according to the present invention is a wheel bearing device in which a hub wheel, a double-row rolling bearing, and a constant velocity universal joint are unitized, and a vehicle body mounting flange to be attached to a suspension device on an outer periphery is integrated. And an outer member having a double row outer rolling surface formed on the inner periphery, a wheel mounting flange integrally formed at one end, and one of the outer members facing the double row outer rolling surface on the outer periphery. A hub ring formed with an inner rolling surface, a cylindrical small-diameter stepped portion extending in the axial direction from the inner rolling surface, and a stem portion fitted to the hub ring, the outer periphery of the double row An inner member composed of an outer joint member of the constant velocity universal joint formed with the other inner rolling surface facing the outer rolling surface, and rolling between both rolling surfaces of the inner member and the outer member. A double row rolling element housed in a freely movable manner, and an annular shape formed between the outer member and the inner member In the wheel bearing device provided with a seal mounted in an opening between the stem portion, the stem portion is press-fitted into the hub wheel via a predetermined shimiro, and an end portion of the fitting portion between the hub wheel and the stem portion is provided. These are joined together at the joints by welding, and the pitch circle diameter of the inner rolling element row of the double row rolling element rows is set larger than the pitch circle diameter of the outer rolling element row. The number of rolling elements on the side is set to be larger than the number of rolling elements on the outer side, and the hub ring is made of medium carbon steel containing 0.40 to 0.80% by weight of carbon and has a predetermined surface hardness. Since the inner rolling base and the base portion on the inner side of the wheel mounting flange that becomes the seal land portion of the seal are subjected to induction hardening, a predetermined hardened layer is formed on the surface. Effective use The hub ring is designed to be lighter and more compact, to increase bearing rigidity and extend the life of the bearing, and without changing the shape and dimensions of the wheel mounting flange, while maintaining the current processing method and existing equipment. Strength and durability can be increased. Further, since the hub wheel and the outer joint member are press-fitted and fixed, it is possible to employ a welding method in which the load applied to the joint portion is small and the heat effect is small. Therefore, the reliability of the joint portion between the hub wheel and the outer joint member can be improved.

  A wheel bearing device in which a hub wheel, a double row rolling bearing and a constant velocity universal joint are unitized, and has a body mounting flange integrally attached to a suspension device on the outer periphery, and a double row on the inner periphery. An outer member formed with an outer rolling surface, a wheel mounting flange integrally formed at one end, one inner rolling surface facing the double row outer rolling surface on the outer periphery, and the inner rolling surface A hub wheel formed with a cylindrical small-diameter step portion extending in the axial direction from the surface, and a stem portion fitted to the hub wheel, and the other inner side facing the double-row outer rolling surface on the outer periphery An inner member composed of an outer joint member of the constant velocity universal joint formed with a rolling surface, and a double row rolling member accommodated between the rolling surfaces of the inner member and the outer member. A seal attached to an opening of an annular space formed between a moving body and the outer member and the inner member In the wheel bearing device, the stem portion is press-fitted into the hub wheel through a predetermined shimiro, and the end portion of the fitting portion of the hub wheel and the stem portion is integrally coupled by a joint portion by laser welding. The pitch circle diameter of the inner side rolling element row of the double row rolling element rows is set to be larger than the pitch circle diameter of the outer side rolling element row, and the number of the inner side rolling elements is the outer circumference. More than the number of rolling elements on the side, and the hub wheel is made of medium carbon steel containing 0.40 to 0.80% by weight of carbon and tempered to set the surface hardness to 35 HRC or less. The inner rolling base and the base portion on the inner side of the wheel mounting flange serving as the seal land portion of the seal are formed with a hardened layer having a surface hardness of 58 to 64 HRC by induction hardening.

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, and FIG. 2 is an enlarged view showing a single hub wheel of FIG.

  This wheel bearing device is configured by unitizing the hub wheel 1, the double row rolling bearing 2 and the constant velocity universal joint 3, and has a configuration referred to as a fourth generation. The double row rolling bearing 2 includes an outer member 4, an inner member 5, and double row rolling elements (balls) 6, 6 accommodated between the two members.

  The outer member 4 is formed of medium carbon steel containing 0.40 to 0.80% by weight of carbon such as S53C, and integrally includes a vehicle body mounting flange 4c to be attached to a knuckle (not shown) on the outer periphery. Double row outer rolling surfaces 4a and 4b are formed on the inner periphery. And these double row outer side rolling surfaces 4a and 4b are hardened by induction hardening in the range of 58-64 HRC surface hardness.

  The inner member 5 includes a hub wheel 1 and an outer joint member 10 to be described later that is fitted into the hub wheel 1. The hub wheel 1 integrally has a wheel mounting flange 7 for mounting a wheel (not shown) at an end portion on the outer side, and is opposed to the double row outer rolling surfaces 4a and 4b on the outer periphery (outer side). ) And a cylindrical small-diameter step portion 1b extending in the axial direction from the inner rolling surface 1a. Hub bolts 8 for fixing the wheels are planted at equal intervals in the circumferential direction of the wheel mounting flange 7.

  The hub wheel 1 is made of medium carbon steel containing 0.40 to 0.80% by weight of carbon such as S53C, and includes a wheel mounting flange that serves as a seal land portion of an outer side seal 19 to be described later, including the inner rolling surface 1a. A predetermined hardened layer 21 (indicated by cross-hatching in the figure) is formed in the range of 58 to 64 HRC by induction hardening from the base portion 24 on the inner side 7 to the small diameter step portion 1b. As a result, the rolling fatigue life of the inner rolling surface 1a is improved, and the strength and rigidity of the small-diameter step portion 1b are increased, and the durability of the hub wheel 1 is improved.

  The constant velocity universal joint 3 includes an outer joint member 10, a joint inner ring 11, a cage 12 and a torque transmission ball 13. The outer joint member 10 is integrally formed with a cup-shaped mouth portion 14, a shoulder portion 15 that forms the bottom of the mouth portion 14, and a stem portion 16 that extends from the shoulder portion 15 in the axial direction. Then, the other (inner side) inner rolling surface 10a facing the double row outer rolling surfaces 4a, 4b of the outer member 4 is formed on the outer periphery of the shoulder portion 15. Are fitted into a cylinder through a predetermined shimoshiro. Thereby, even if a moment load is applied to the hub wheel 1, it can be supported by the outer peripheral surface of the stem 16, and the rigidity of the hub wheel 1 is improved.

  The outer joint member 10 is made of medium carbon steel containing 0.40 to 0.80% by weight of carbon such as S53C, and is induction hardened from the outer periphery of the shoulder portion 15 to the stem portion 16 including the inner rolling surface 10a. Thus, a predetermined hardened layer 22 (indicated by cross-hatching in the figure) is formed with a surface hardness in the range of 58 to 64 HRC, and the end portion of the stem portion 16 is left as it is after forging. As a result, the strength and rigidity of the outer joint member 10 are increased and durability is improved, and the end of the fitting portion of the stem portion 16 to be welded and the hub wheel 1 is not formed with a hardened layer on the surface. Since it is a quenched portion, harmful carbon that affects the welding strength is not precipitated, and the welding strength can be further increased.

  Double-row rolling elements 6, 6 are accommodated between the rolling surfaces 4a, 1a and 4b, 10a of the outer member 4 and the inner member 5, and these double-row rolling elements 6, 18 are held by the cages 17, 18; 6 is rotatably held. Further, seals 19 and 20 are attached to the opening of the annular space formed between the outer member 4 and the inner member 5, leakage of lubricating grease sealed inside the bearing, rainwater, dust, etc. from the outside Is prevented from entering the inside of the bearing. Here, the double-row angular contact ball bearing using balls as the rolling elements 6 is illustrated as the double-row rolling bearing 2, but not limited to this, for example, double-row tapered roller bearings using tapered rollers as the rolling elements. It may be.

  Here, in the present embodiment, the pitch circle diameter PCDi of the six inner rolling elements is set larger than the pitch circle diameter PCDo of the outer six rolling elements. That is, the groove bottom diameter of the inner rolling surface 10a of the outer joint member 10 in the inner member 5 is the inner rolling force of the hub wheel 1 due to the difference between the double row rolling elements 6 and the pitch circle diameters PCDo and PCDi of the six rows. The diameter is larger than the groove bottom diameter of the running surface 1a. On the other hand, in the outer member 4, the groove bottom diameter of the inner side outer rolling surface 4b is formed larger than the groove bottom diameter of the outer side outer rolling surface 4a. Therefore, the outer diameters of the double-row rolling elements 6 and 6 are the same, but the pitch circle diameters PCDo and PCDi can be made different by effectively utilizing the bearing space, and the number of the inner-side rolling elements 6 rows can be reduced. It is possible to accommodate more than the number of the six rolling elements on the outer side. Therefore, it is possible to reduce the weight and size of the apparatus, increase the bearing rigidity, and extend the life of the bearing.

  The stem portion 16 of the outer joint member 10 is cylindrically fitted to the hub wheel 1 via a predetermined shimiro, and the shoulder portion 15 of the outer joint member 10 is abutted against the end surface of the small diameter step portion 1b. With the bearing preload applied, the end of the fitting portion between the hub wheel 1 and the stem portion 16 is integrally coupled by a joint 23 by laser welding.

  This laser welding is performed by irradiating a high energy density laser beam condensed by a condensing unit to the joint portion, and rapidly raising the temperature of the joint portion 23 to cause local melting and solidification. And a condensing unit is moved to the circumferential direction along the edge part of a fitting part, and the edge part of the fitting part of the hub wheel 1 and the outer joint member 10 is joined over the perimeter. Thereby, welding time can be shortened and the heat influence by welding can be suppressed to the minimum.

  Examples of the welding method include plasma welding, electron beam welding, and high-speed pulse projection welding in addition to laser welding. By adopting these welding methods, it is possible to suppress the tempering of the surface hardness due to the thermal influence on the bearing rolling surface and the like, and in the range of carbon amount of 0.40 to 0.80% by weight, It is possible to prevent the occurrence of burning cracks in the vicinity of the weld.

  In addition, since the hub wheel 1 and the stem portion 16 of the outer joint member 10 can transmit torque via the press-fitting fitting surface, a welding method in which the load on the joint portion 23 is small and the heat influence is small should be adopted. Can do. Accordingly, it is possible to improve the rigidity and durability, and improve the reliability of the joint portion between the outer joint member 10 of the constant velocity universal joint 3 and the hub wheel 1.

  The hub wheel 1 is formed into a desired shape / dimension by turning after hot forging the material, and then subjected to a tempering process to be described later. As shown in FIG. 2, the outer base portion of the wheel mounting flange 7, that is, between the brake rotor mounting surface 26 and the cylindrical pilot portion 27 serving as a support surface of the brake rotor (not shown). The corner 28 is formed in an arcuate surface (or a slug) having a radius of curvature that does not interfere with the brake rotor.

  In the present embodiment, the hub wheel 1 is subjected to a so-called tempering treatment in which high-temperature tempering at 400 ° C. or higher with a high frequency is performed to obtain a troostite or sorbite structure. By this tempering treatment, the structure is granulated, and mechanical properties such as tension, bending, and impact value are increased, and ductility and toughness are increased. Here, the surface hardness of the brake rotor mounting surface 26, the pilot portion 27, and the corner portion 28 of the wheel mounting flange 7 after the tempering process is set to 35 HRC or less by the tempering process of the hub wheel 1. Thereby, workability, such as cutting, can be improved and heat treatment deformation can be suppressed. Further, the surface hardness of the bolt hole 25 of the hub bolt 8 that is press-fitted into the wheel mounting flange 7 approaches the surface hardness of the hub bolt 8, and when the hub bolt 8 is press-fitted, the knurles 9 are crushed and the fixing force is reduced. Can be prevented, and deformation of the brake rotor mounting surface 26 after press-fitting can be prevented to suppress surface runout that causes brake judder.

  In this way, the hub wheel 1 is subjected to a tempering process after turning and set to a desired surface hardness, so that the shape and dimensions of the wheel mounting flange 7 are not changed, and the current machining method and existing equipment are changed. As it is, the strength of the corner portion 28 and the base portion 24, which are the weakest portions of rotational bending fatigue, can be increased, and the durability can be improved while reducing the weight and size of the hub wheel 1.

  In order to further improve the surface runout of the brake rotor mounting surface 26 in the wheel mounting flange 7, the brake rotor mounting surface 26 can be turned after the hub bolt 8 is press-fitted, so that the hardened corners can be hardened as in the prior art. There is no possibility that a step due to the turning process occurs on the brake rotor mounting surface 26 due to the difference in hardness from the portion.

  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 having a fourth generation structure in which a hub wheel and an outer joint member are integrally coupled.

It is a longitudinal section showing one embodiment of a wheel bearing device concerning the present invention. It is an enlarged view which shows the hub ring single-piece | unit of FIG. It is a longitudinal cross-sectional view which shows the conventional wheel bearing apparatus. It is an enlarged view which shows the hub ring single-piece | unit of FIG.

Explanation of symbols

1 ... hub wheel 1a, 10a ... inner rolling surface 1b ... small diameter step 2 ... ····································································································· Member 4a, 4b ... Outer rolling surface 4c ... Car body mounting flange 5 ... Inner member 6 ... rolling element 7 ... wheel mounting flange 8 ... hub bolt 9 ··························································· Outer joint member 11・ ・ ・ ・ ・ ・ ・ ・ ・ Cage 13 ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ Torque transmission ball 14 ・ ・ ・ ・ ・ ・...... Mouse part 15 ... Shoulder part 16 ... Stem part 17, 18 ... Vessels 19 and 20 ·········· Seals 21 and 22 ·······························································・ ・ ・ ・ ・ ・ Base 25 on the inner side of the wheel mounting flange ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ Bolt hole 26 ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ Brake rotor mounting surface 27・ ・ ・ ・ ・ ・ ・ ・ ・ Pilot 28 ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ Corner 50 ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ Inner member 51 ・ ・ ・ ・ ・ ・・ ・ ・ ・ ・ Hub wheel 52 ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ Inner ring 53, 54 ・ ・ ・ ・ ・ ・ ・ ・ Rolling element 55 ・ ・ ・ ・ ・ ・ ・ ・ Outside Member 56 .... Constant velocity universal joint 57 ... Brake rotor 58 Wheel mounting flange 59 Brake rotor mounting surface 60・ ・ ・ ・ ・ Pilot part 61 ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ Corner 62, 63, 65 ・ ・ ・ ・ ・ ・ Surface hardened layer 64 ・ ・ ・ ・ ・ ・ Serration Parts a to d ······· Part PCDi ········ Pitch circle diameter PCDo of the inner side rolling element row ········ Outer side Pitch circle diameter of rolling element row

Claims (6)

A wheel bearing device in which a hub wheel and a double row rolling bearing and a constant velocity universal joint are unitized,
An outer member integrally having a vehicle body mounting flange to be attached to the suspension device on the outer periphery, and having a double row outer rolling surface formed on the inner periphery;
One end has a wheel mounting flange integrally, and on the outer periphery is one inner rolling surface facing the double row outer rolling surface, and a cylindrical small-diameter step portion extending in the axial direction from the inner rolling surface. The constant velocity universal joint having a formed hub wheel and a stem portion fitted to the hub wheel, and having the other inner rolling surface opposed to the outer rolling surface of the double row on the outer periphery. An inner member made of an outer joint member;
A double row rolling element housed so as to be freely rollable between both rolling surfaces of the inner member and the outer member;
In a wheel bearing device comprising a seal mounted in an opening of an annular space formed between the outer member and the inner member,
The stem portion is press-fitted into the hub wheel through a predetermined shimoshiro, the ends of the fitting portion of the hub wheel and the stem portion are integrally joined by a welded joint portion, and the hub wheel is carbon 0. An inner base portion of the wheel mounting flange that is formed of medium carbon steel containing 40 to 0.80% by weight and is tempered to a predetermined surface hardness and serves as a seal land portion of the inner rolling surface and the seal A wheel bearing device in which a predetermined hardened layer is formed on the surface by induction hardening.   The wheel bearing device according to claim 1, wherein the surface hardness of the hub wheel after the tempering treatment is set to 35 HRC or less.   The wheel bearing device according to claim 1, wherein the joint portion is formed by laser welding that moves the light collecting unit in a circumferential direction along an end portion of the fitting portion between the hub wheel and the outer joint member. .   The outer joint member is made of medium carbon steel containing 0.40 to 0.80% by weight of carbon such as S53C, and has a high frequency from the outer periphery of the shoulder portion including the inner rolling surface to the stem portion. The wheel bearing device according to any one of claims 1 to 3, wherein a predetermined hardened layer is formed by quenching, and an end portion of the stem portion is left raw after forging.   The wheel bearing device according to any one of claims 1 to 4, wherein the brake rotor mounting surface is turned after a hub bolt is press-fitted into the wheel mounting flange.   The pitch circle diameter of the inner side rolling element row of the double row rolling element rows is set larger than the pitch circle diameter of the outer side rolling element row, and the number of inner side rolling elements is the outer side. The wheel bearing device according to any one of claims 1 to 5, wherein the number is set to be larger than the number of rolling elements.

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