JP2008128451A - Bearing device for wheel - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a bearing device for vehicle of a fourth generation structure, which is reduced in cost in addition to reduction in weight and size. <P>SOLUTION: In the bearing device for wheel of the fourth generation structure in which a hub wheel 1 and an outside joint member 10 are coupled so as to be torque-transmittable, a mortar-like recessed part 23 is formed with substantially a uniform thickness by forging on the inner circumference of an outer-side end part in conformation to the shape of the outer circumferential surface of the hub wheel 1. A female thread 8 is formed on the inner circumference of the hub wheel 1, and a fixing bolt 21 is screwed to this thread and fastened until the hub wheel 1 and the outside joint member 10 are laid in a butt state where a head part 21a abuts on the inner end surface of a shoulder part 15 of the outer joint member 10. Of double-row balls of six rows, the pitch circle diameter PCDi of the inner six rows of balls is set larger than the pitch circle diameter PCDo of the outer six rows of balls, and the number of balls of the inner six rows of balls is set larger than that of the outer six rows of balls. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a wheel bearing device for rotatably supporting a wheel of an automobile or the like with respect to a suspension device, and more specifically, a fourth generation structure in which a hub wheel, a constant velocity universal joint and a double row rolling bearing are unitized. The present invention relates to a wheel bearing device.

  A wheel bearing device for rotatably supporting a wheel of an automobile or the like is a second generation having a body mounting flange integrally with an outer member from a structure called a first generation that uses a double row rolling bearing alone. In addition, the third generation in which one inner rolling surface of the double row rolling bearing is integrally formed on the outer periphery of the hub ring integrally having the wheel mounting flange, and further, the constant velocity universal joint is provided on the hub ring. Have been developed to the fourth generation in which the other inner rolling surface of the double row rolling bearing is integrally formed on the outer periphery of the outer joint member constituting the constant velocity universal joint.

  The wheel bearing device shown in FIG. 2 is a typical example of a fourth generation structure. This wheel bearing device is configured by unitizing a hub wheel 51, a double row rolling bearing 52, and a constant velocity universal joint 53. 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).

  The hub wheel 51 integrally has a wheel mounting flange 54 for mounting a wheel (not shown) at an end portion on the outer side, and hub bolts 56 are implanted at circumferentially equidistant positions. Further, an uneven portion 55 is formed on the inner peripheral surface of the hub wheel 51, and the surface hardness is set to a range of 54 to 64HRC by induction hardening.

  The double-row rolling bearing 52 includes an outer member 57, an inner member 58, and double-row balls 59, 59. The outer member 57 integrally has a vehicle body mounting flange 57b for mounting to a suspension device (not shown) on the outer periphery, and double row outer rolling surfaces 57a and 57a are formed on the inner periphery. On the other hand, the inner member 58 includes a hub wheel 51 and an outer joint member 63 that is fitted into the small diameter step portion 51b of the hub wheel 51 in a butt-fit state. An outer side inner rolling surface 51a and an inner side inner rolling surface 63a are directly formed on the outer circumferences of the hub wheel 51 and the outer joint member 63, respectively, and double row balls 59, 59 are formed on the rolling surfaces 57a, 51a. And 57a and 63a, respectively, and are held by the cages 60 and 60 so as to be freely rotatable. In addition, seals 61 and 62 are attached to the end of the double row rolling bearing 52 to prevent leakage of lubricating grease sealed inside the bearing and intrusion of rainwater and dust from the outside into the bearing. ing.

The constant velocity universal joint 53 includes an outer joint member 63, a joint inner ring 64, a cage 65, and a torque transmission ball 66. The outer joint member 63 integrally includes a cup-shaped mouth portion 67, a shoulder portion 68 that forms the bottom portion of the mouth portion 67, and a hollow stem portion 69 that extends from the shoulder portion 68 in the axial direction. Formed on the outer periphery of the stem portion 69 are an inrow portion 69a fitted into the small diameter step portion 51b of the hub wheel 51 and a fitting portion 69b extending further in the axial direction from the inrow portion 69a. Then, a diameter expanding jig such as a mandrel is pushed into the inner diameter of the stem portion 69 to increase the diameter of the fitting portion 69b, and the fitting portion 69b is bitten into the uneven portion 55 of the hub wheel 51 and caulked to be tightened. And the outer joint member 63 are integrally plastically coupled. As a result, it is possible to provide a wheel bearing device that is lighter and more compact, and that prevents loosening of the coupling portion over a long period of time even when a large moment load is applied, and has improved durability.
Japanese Patent Laid-Open No. 2001-18605

  In such a conventional wheel bearing device, the fitting portion 69b of the stem portion 69 of the outer joint member 63 is expanded in diameter so as to bite into the uneven portion 55 of the hub wheel 51, and the hub wheel 51 and the outer joint member 63 are plastically coupled. Therefore, the stem portion 69 needs to have a hollow structure in advance. However, since the stem portion 69 has a long axial length, not only does the material cost increase, but the number of forging and cutting processes for forming the hollow structure increases, which causes an increase in cost.

  In addition, in order to improve the fuel efficiency of the vehicle and the movement performance by reducing the unsprung weight and weight, it is desired to improve the bearing rigidity as well as the durability while reducing the weight and compactness that are the characteristics of the fourth generation structure. At the same time, cost reduction is required.

  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 having a fourth generation structure that achieves a reduction in cost and weight while achieving light weight and compactness.

  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 to be integrally attached, an outer member having a double row outer raceway formed on the inner periphery, and a wheel mounting flange for integrally attaching a wheel to one end, A hub wheel having one inner rolling surface facing the outer rolling surface of the double row on the outer periphery, a small-diameter step portion extending in the axial direction from the inner rolling surface, and a small-diameter step portion of the hub ring; The constant-velocity freely has a hollow shoulder portion that is externally fitted through a serration, and the other inner rolling surface that faces the outer rolling surface of the double row is formed on the outer periphery of the shoulder portion. An inner member composed of an outer joint member of the joint, and the inner member and the outer member. A wheel bearing device in which the hub wheel and the outer joint member are coupled so as to be able to transmit torque, and are arranged on an inner periphery of the hub wheel. A female screw is formed, and a fixing bolt is screwed into the female screw. The head of the fixing bolt is brought into contact with the inner end surface of the shoulder of the outer joint member, so that the hub wheel and the outer joint member are brought into abutting state. Of the double row rolling element rows, the inner diameter of the rolling circle is set larger than the pitch diameter of the outer rolling element row, and the inner rolling element row The number of rolling elements is set to be larger than the number of rolling elements in the outer rolling element row.

  As described above, in the wheel bearing device having the fourth generation structure in which the hub wheel and the outer joint member are coupled so as to be able to transmit torque, a female screw is formed on the inner periphery of the hub wheel, and a fixing bolt is screwed into the female screw. The head of the fixing bolt is brought into contact with the inner end surface of the shoulder of the outer joint member and tightened until the hub wheel and the outer joint member are brought into abutting state, and the inner side of the double row of rolling element rows The pitch circle diameter of the rolling element row is set to be larger than the pitch circle diameter of the outer rolling element row, and the number of rolling elements in the inner rolling element row is larger than the number of rolling elements in the outer rolling element row. Since many of these are set, it is possible to increase the bearing rigidity and extend the life of the bearing as well as to reduce the weight and size of the device, and to cut the inner diameter of the outer joint member into a hollow stem shape that is long in the axial direction by cutting. No need to hub It is possible to provide a wheel bearing apparatus of low cost fourth generation structure by a simple fastening means with the outer joint member.

  Preferably, as in the invention described in claim 2, a mortar-shaped recess is formed by forging on the inner periphery of the outer side end of the hub wheel so as to correspond to the shape of the outer peripheral surface of the hub wheel. If the outer end of the wheel is formed with a substantially uniform thickness, the material weight of the hub wheel and the man-hours for cutting can be reduced, further reducing weight and cost. Can do.

  Further, as in the third aspect of the invention, if the fixing bolt is fixed to the hub ring by a crimping portion formed by plastically deforming an end portion of the fixing bolt and biting into the hub ring. It is possible to prevent the fixing bolt from loosening due to vibration during operation for a long period of time.

  Further, as in the invention described in claim 4, if the double row rolling elements are constituted by balls and the outer diameters of these balls are set to be the same, the problem of misassembly in the assembly process is solved. This improves quality reliability.

  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. An outer member having a double row outer rolling surface formed on the inner periphery, and a wheel mounting flange for mounting the wheel on one end, and the outer surface of the double row on the outer periphery. A hub ring formed with an inner rolling surface facing the inner rolling surface, a small-diameter step portion extending in the axial direction from the inner rolling surface, and a hollow shape that is externally fitted to the small-diameter step portion of the hub ring via serrations An inner member comprising the outer joint member of the constant velocity universal joint, wherein the other inner rolling surface facing the outer rolling surface of the double row is formed on the outer periphery of the shoulder portion. And can be rolled between the rolling surfaces of the inner member and the outer member. In the wheel bearing device in which the hub wheel and the outer joint member are coupled so as to be able to transmit torque, a female screw is formed on the inner periphery of the hub wheel, and a fixing bolt is attached to the female screw. The fixing bolt is brought into contact with the inner end surface of the shoulder portion of the outer joint member and tightened until the hub wheel and the outer joint member are brought into abutting state. The pitch circle diameter of the inner side rolling element row is set larger than the pitch circle diameter of the outer side rolling element row, and the number of rolling elements in the inner side rolling element row is the outer side rolling element row. The number of rolling elements is set to be larger than the number of rolling elements, so that not only can the equipment be lighter and more compact, but also the bearing rigidity can be increased and the bearing life can be extended. Long hollow stem shape That requires no, it is possible to provide a wheel bearing apparatus of low cost fourth generation structure by a simple fastening means of the hub wheel and the outer joint member.

  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, and a wheel mounting flange for mounting a wheel at one end, and one inner rolling surface facing the double row outer rolling surface on the outer periphery; And a hub wheel formed with a small-diameter step portion extending in the axial direction from the inner rolling surface, and a hollow shoulder portion that is externally fitted to the small-diameter step portion of the hub wheel via a serration, An inner member composed of an outer joint member of the constant velocity universal joint, wherein the other inner rolling surface facing the outer rolling surface of the double row is formed on the outer periphery of the shoulder, and the inner member and the outer A double row of ball rows accommodated in a freely rolling manner between the rolling surfaces of the member. In the wheel bearing device in which the hub wheel and the outer joint member are coupled so as to be able to transmit torque, a mortar-shaped recess is formed by forging the inner periphery of the outer side end of the hub wheel so as to correspond to the shape of the outer peripheral surface of the hub wheel. The outer end of the hub wheel is formed to have a substantially uniform thickness, and a female thread is formed on the inner periphery of the hub ring. The head of the fixing bolt is brought into contact with the inner end surface of the shoulder portion of the member and tightened until the hub wheel and the outer joint member are brought into abutting state, and the inner side ball of the double row ball row The pitch circle diameter of the row is set larger than the pitch circle diameter of the outer side ball row, and the number of balls in the inner side ball row is set larger than the number of balls in the outer side ball row.

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.
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 made of medium and high carbon steel containing 0.40 to 0.80% by weight of carbon such as S53C, and a vehicle body mounting flange 4c to be attached to a knuckle (not shown) constituting the suspension device is integrally formed. And 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 on the outer periphery on one (outer side) inner rolling which faces the outer rolling surface 4a. A surface 1a and a cylindrical small-diameter step portion 1b extending in the axial direction from the inner rolling surface 1a are formed. A female screw 24 to which a wheel bolt (not shown) for fixing the wheel is fastened is formed in the circumferential direction of the wheel mounting flange 7. The hub wheel 1 is made of medium and high carbon steel containing 0.40 to 0.80% by weight of carbon, such as S53C, and has a high frequency from the inner rolling surface 1a to the small diameter step 1b from the base of the wheel mounting flange 7. The surface hardness is hardened by quenching to a range of 58 to 64 HRC.

  Here, an internal thread 8 is formed on the inner periphery of the hub wheel 1. In addition, serrations (or splines) 9 are formed on the outer periphery of the small diameter step portion 1b. The outer surface of the serration 9 is subjected to a predetermined curing process by induction hardening.

  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 and a cylindrical shoulder portion 15 having a small diameter formed from the mouth portion 14. The outer periphery of the shoulder 15 is formed with the other (inner side) inner rolling surface 10a facing the outer rolling surface 4b of the outer member 4, and the hub wheel 1 is formed on the inner periphery. Serrations (or splines) 16 that engage with the serrations 9 are formed.

  The outer joint member 10 is formed of medium and high carbon steel containing 0.40 to 0.80% by weight of carbon such as S53C, and is surfaced by induction hardening from the outer periphery of the shoulder portion 15 to the inner rolling surface 10a and the end portion. Hardening is performed in the range of 58 to 64 HRC. Further, the outer surface of the serration 16 is subjected to a predetermined curing process by induction hardening.

  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 are each hold | maintained so that rolling is possible. In the present embodiment, the pitch circle diameter PCDi of the six inner rolling elements is set to be 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. Accordingly, although the size of the double row rolling elements 6 and 6 rows is the same, 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, solve the problem of erroneous assembly in the assembly process, improve the reliability of the quality, increase the bearing rigidity and extend the life of the bearing.

  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.

  In the hub wheel 1 and the outer joint member 10, the shoulder 15 of the outer joint member 10 is fitted to the small-diameter step portion 1b of the hub wheel 1 through serrations 9 and 16, and the outer joint member 10 is attached to the end surface of the small-diameter step portion 1b. The shoulder portions 15 are connected so as to be able to transmit torque in a state of being abutted, and are integrated in the axial direction by fixing bolts 21. That is, the head 21 a of the fixing bolt 21 is brought into contact with the inner end surface of the shoulder portion 15, and the male screw 21 b of the fixing bolt 21 is fastened to the female screw 8 of the hub wheel 1 with a predetermined tightening torque. Thereby, a predetermined bearing preload can be applied with a simple configuration.

  Further, in the present embodiment, after the hub wheel 1 and the outer joint member 10 are fastened, the end portion of the male screw 21b of the fixing bolt 21 is plastically deformed, and the caulking portion 22 formed by biting into the female screw 8 of the hub wheel 1 is used. A fixing bolt 21 is fixed to the hub wheel 1. Thereby, it is possible to prevent the fixing bolt 21 from being loosened due to vibration or the like during operation for a long period of time. In addition, although not shown, the end of the male screw 21b of the fixing bolt 21 and the hub wheel 1 may be welded to prevent loosening.

  In the present invention, such a means for integrally connecting the hub wheel 1 and the outer joint member 10 is employed without impairing the characteristics of the fourth generation structure such as light weight and compactness. The axial length of the portion can be shortened, and the extra wall at the outer side end of the hub wheel 1 can be reduced as much as possible. That is, a mortar-shaped recess 23 is formed on the inner periphery of the outer end portion by forging so as to correspond to the shape of the outer peripheral surface of the hub wheel 1 and can be formed to have a substantially uniform thickness. Therefore, it is possible to reduce the material weight of the outer joint member 10 and the hub wheel 1 and the man-hours for cutting, thereby further reducing the weight and cost.

  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, a constant velocity universal joint, and a double row rolling bearing are unitized.

It is a longitudinal section showing one embodiment of a wheel bearing device concerning the present invention. It is a longitudinal cross-sectional view which shows the conventional wheel bearing apparatus.

Explanation of symbols

1 ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ Hub wheel 1a, 10a ・ ・ ・ ・ ・ ・ Inner rolling surface 1b ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ Small diameter step 2 ・ ・ ・············· Double row rolling bearing 3 ·····················································・ ・ ・ ・ Outer rolling surface 4c ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ Car body mounting flange 5 ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ Inner member 6 ・ ・ ・ ・ ・ ・ ・ ・.... Rolling element 7 ..... Wheel mounting flange 8 ..... Female thread 9, 16 ..... Serration 10 ··············· Outer joint member 11 ······················································································ ... Torque transmission ball 14 ... Mouse part 15 ...・ ・ ・ ・ ・ Shoulders 17 and 18 ・ ・ ・ Cage 19 and 20 ・ ・ ・ Seal 21 ・ ・ ・ ・ ・ ・ ・ ・ Fixing bolt 21a ・ ・ ・········ Head 21b ······················································································· ····································································································· Hub Rings 51a, 63a・ ・ ・ ・ ・ Double row rolling bearing 53 ・ ・ ・ ・ ・ ・ Constant velocity universal joint 54 ・ ・ ・ ・ ・ ・ Wheel mounting flange 55 ・ ・ ・ ・ ・ ・ ・ ・... Uneven part 56 ... Hub bolt 57 ... Outer member 57a .... Body mounting flange 58 ...・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ Inner member 59 ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ Ball 60 ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ Retainer 61, 62 ・ ・ ・ ・ ・ ・ ・ ・ Seal 63・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ Outer joint member 64 ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ Fitting inner ring 65 ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ Cage 66 ・ ・ ・ ・ ・ ・ ・ ・・ ・ ・ Torque transmission ball 67 ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ Mouse part 68 ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ Shoulder 69 ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ Stem part 69 a ·············································································································· Pitch circle diameter PCDo ... Pitch circle diameter of outer rolling element row

Claims (4)

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;
A wheel mounting flange for mounting a wheel at one end is integrally formed, one inner rolling surface facing the outer rolling surface of the double row on the outer periphery, and a small diameter step extending in the axial direction from the inner rolling surface A hub ring formed with a portion, and a hollow shoulder that is externally fitted via a serration to a small-diameter step portion of the hub ring, and the outer circumferential surface of the double row on the outer periphery of the shoulder An inner member composed of an outer joint member of the constant velocity universal joint on which the other inner rolling surface facing the inner surface is formed;
For a wheel comprising the inner member and a double row rolling element row accommodated between both rolling surfaces of the outer member and the outer member, wherein the hub wheel and the outer joint member are coupled to transmit torque. In the bearing device,
A female screw is formed on the inner periphery of the hub wheel, and a fixing bolt is screwed into the female screw, and the head of the fixing bolt is brought into contact with the inner end surface of the shoulder of the outer joint member. The members are tightened until they are brought into contact with each other, and 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. The wheel bearing device is characterized in that the number of rolling elements in the inner side rolling element row is set larger than the number of rolling elements in the outer side rolling element row.   A mortar-shaped recess is formed by forging in the inner periphery of the outer end of the hub wheel so as to correspond to the shape of the outer peripheral surface of the hub wheel, and the outer end of the hub wheel has a substantially uniform thickness. The wheel bearing device according to claim 1, wherein the wheel bearing device is formed.   The wheel bearing device according to claim 1 or 2, wherein the fixing bolt is fixed to the hub wheel by a caulking portion formed by plastically deforming an end portion of the fixing bolt and biting into the hub wheel.   The wheel bearing device according to any one of claims 1 to 3, wherein the double row rolling elements are formed of balls, and the outer diameters of the balls are set to be the same.

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