JP2008169860A - Wheel bearing device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a wheel bearing device having improved strength and durability while solving conflicting issues of constructing the device to be lighter and more compact and to be more rigid. <P>SOLUTION: The wheel bearing device comprises double-row rolling element trains, and an inner ring 6 axially fixed with a caulked portion 13c formed by plastically deforming the end of a small diameter stepped portion 13b of a hub ring 13 outward in the radial direction. The rolling element train on the outer side out of the double-row rolling element trains consists of tapered rollers 9, and the rolling element train on the inner side consists of balls 10. A pitch circle diameter PCDo of the tapered roller train 9 on the outer side is set to be larger than a pitch circle diameter PCDi of the ball train 10 on the inner side, and the number of the tapered rollers 9 is set to be the same as that of the balls 10. Thus, the thickness of the hub ring 13 is increased to increase the strength and an operating point distance is increased to improve the rigidity and life of the bearing as a whole while actualizing lighter and more compact construction. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a wheel bearing device that rotatably supports a wheel of an automobile or the like, and more particularly to a wheel bearing device that is reduced in weight and increased in rigidity.

  2. Description of the Related Art Conventionally, a wheel bearing device for supporting a wheel of an automobile or the like is such that a hub wheel for mounting a wheel is rotatably supported via a rolling bearing, and there are a drive wheel and a driven wheel. For structural reasons, an inner ring rotation method is generally used for driving wheels, and an inner ring rotation method and an outer ring rotation method are generally used for driven wheels. As the wheel bearing device, a double-row angular ball bearing having a desired bearing rigidity, exhibiting durability against misalignment, and having a small rotational torque from the viewpoint of improving fuel efficiency is often used. On the other hand, double row tapered roller bearings are used in vehicles such as off-road cars and trucks that have a heavy vehicle body weight.

  Further, the wheel bearing device has a structure called a first generation in which a wheel bearing composed of a double row angular ball bearing or the like is fitted between a knuckle and a hub wheel constituting a suspension device. Second generation structure in which body mounting flange or wheel mounting flange is formed directly on the outer periphery of the member, third generation structure in which one inner rolling surface is directly formed on the outer periphery of the hub wheel, or hub wheel, etc. It is roughly classified into a fourth generation structure in which the inner rolling surface is directly formed on the outer periphery of the outer joint member of the speed universal joint.

  Of these, the wheel bearing device shown in FIG. 3 is called a third generation structure on the drive wheel side, and includes an inner member 52 comprising a hub wheel 50 and an inner ring 51 fixed to the hub wheel 50, And an outer member 53 inserted on the member 52. 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).

  This wheel bearing device has a vehicle body mounting flange 53c integrally attached to a knuckle (not shown) on the outer periphery, and an outer member in which double row outer rolling surfaces 53a and 53b are formed on the inner periphery. 53 and a wheel mounting flange 54 for mounting a wheel (not shown) at one end thereof are integrally formed and opposed to the outer-side outer rolling surface 53a of the double-row outer rolling surfaces 53a and 53b on the outer periphery. The inner raceway surface 50a, the hub wheel 50 formed with the small diameter step portion 50b extending in the axial direction from the inner raceway surface 50a, and the small diameter step portion 50b of the hub wheel 50 are fitted on the outer side of the double row. Of the rolling surfaces 53a and 53b, an inner member 52 comprising an inner ring 51 formed with an inner rolling surface 51a facing the inner outer rolling surface 53b, and a tapered roller accommodated between these rolling surfaces. 55 and ball 56 and this Is composed of a rolling bearing of double row that includes a retainer 57, 58 for holding the Luo tapered rollers 55 and balls 56 rollably.

  Seals 59 and 60 are attached to the opening of the annular space formed between the outer member 53 and the inner member 52, leakage of the lubricating grease sealed inside the bearing, and rainwater entering the bearing from the outside. And dust are prevented from entering.

As described above, this conventional wheel bearing device uses the tapered roller 55 as the outer rolling element, so that the rigidity is improved not only when the vehicle is stationary but also when turning, so that the wheel bearing device is provided. Can be prolonged (see, for example, Patent Document 1).
JP 2003-232343 A

  In such a conventional wheel bearing device, since the tapered roller 55 is used for the outer rolling element, the rigidity of the outer bearing row is improved while avoiding the increase in size of the device, and the length of the wheel bearing device is increased. Life can be extended. However, in such a conventional wheel bearing, there has been a problem of increasing the rigidity on the inner side while suppressing an increase in weight.

  The present invention has been made in view of such circumstances, and provides a wheel bearing device that simultaneously solves the conflicting problems of lightweight, compact and high rigidity of the device, and has improved strength and durability. The purpose is to do.

  In order to achieve the object, the invention according to claim 1 of the present invention has a vehicle body mounting flange integrally attached to the knuckle on the outer periphery, and a double row outer rolling surface is formed on the inner periphery. An outer member and a wheel mounting flange for mounting a wheel at one end are integrally formed, a hub wheel having a small-diameter step portion formed on the outer periphery, and press-fitted into the small-diameter step portion of the hub wheel, and An inner member composed of at least one inner ring formed with an inner rolling surface opposite to the outer rolling surface of the row, and a roller is interposed between both rolling surfaces of the inner member and the outer member via a cage. In the wheel bearing device including a double row rolling element row accommodated in a freely movable manner, an outer side rolling element row of the double row rolling element rows is constituted by a tapered roller, and an inner side rolling element row is provided. Is composed of balls, and the pitch of the outer tapered roller row Diameter than the pitch circle diameter of the ball train in the inner side is set to be larger in diameter, the number of tapered rollers and balls is set to be the same.

  Thus, in the wheel bearing device having the second or third generation structure provided with the double row rolling element rows, the outer side rolling element row of the double row rolling element rows is constituted by the tapered roller, and the inner side The rolling element train of the ball is composed of balls, the pitch circle diameter of the outer tapered roller train is set to be larger than the pitch circle diameter of the inner ball train, and the number of these tapered rollers and balls is the same. As a result, the basic load rating of the outer side bearing row is increased compared to the inner side, and the rigidity and life can be improved. In addition, by setting the pitch circle diameter of the outer side tapered roller row to be larger than the pitch circle diameter of the inner side ball row, the hub ring becomes thicker and the strength can be increased. It is possible to provide a wheel bearing device in which the working point distance of the double-row bearing with the pitch circle diameter enlarged is increased and the overall bearing rigidity and life are improved.

  Preferably, as in the invention described in claim 2, a tapered inner rolling surface is directly formed on the outer periphery of the hub wheel, and the small-diameter step portion extending in the axial direction from the inner rolling surface is formed. If the inner ring is press-fitted into the small-diameter step portion through a predetermined scissors, the device can be further reduced in weight and size.

  Further, as in the invention described in claim 3, a large hook for guiding the tapered roller is formed on the large diameter side of the inner rolling surface, and a cage for holding the tapered roller includes the tapered roller. If it is formed so as to prevent the roller from falling off in the radial direction, a small punch for preventing the tapered roller from falling off on the small diameter side of the inner rolling surface can be eliminated, improving the workability of the hub ring. In addition, the assembly work can be simplified and the assembly can be automated, thereby reducing the cost.

  Further, as in the invention described in claim 4, if the inner ring is fixed in the axial direction by a caulking portion formed by plastically deforming the end portion of the small diameter step portion radially outward, the weight is further reduced.・ Compact size can be achieved.

  The wheel bearing device according to the present invention has an outer member integrally formed with a vehicle body mounting flange to be attached to the knuckle on the outer periphery, a double row outer rolling surface formed on the inner periphery, and a wheel at one end. A hub wheel integrally having a wheel mounting flange for mounting a small diameter stepped portion on the outer periphery, and press-fitted into the small diameter stepped portion of the hub wheel, facing the outer circumferential rolling surface of the double row on the outer periphery. An inner member formed of at least one inner ring formed with an inner rolling surface, and a double row of the inner member and the outer member that are rotatably accommodated between the rolling surfaces of the inner member and the outer member via a cage. In the wheel bearing device comprising a rolling element row, the outer side rolling element row of the double row rolling element rows is constituted by a tapered roller, the inner side rolling element row is constituted by a ball, and Ball with pitch circle diameter of outer tapered roller train on inner side The diameter is set to be larger than the pitch circle diameter, and the number of these tapered rollers and balls is set to be the same. Therefore, the basic load rating of the outer bearing row is increased and the rigidity and life are improved compared to the inner side. Can be made. In addition, by setting the pitch circle diameter of the outer side tapered roller row to be larger than the pitch circle diameter of the inner side ball row, the hub ring becomes thicker and the strength can be increased. It is possible to provide a wheel bearing device in which the operating point distance of the double row bearings is increased and the overall bearing rigidity and life are improved.

  A body mounting flange for mounting to the knuckle on the outer periphery is integrated, an outer member with a double row outer raceway formed on the inner periphery, and a wheel mounting flange for mounting the wheel on one end is integrated. A hub ring having an inner rolling surface facing one of the outer rolling surfaces 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 of the hub ring An inner member composed of an inner ring that is press-fitted into a stepped portion and has an inner rolling surface formed on the outer periphery facing the other of the double row outer rolling surfaces, and both rolling of the inner member and the outer member. The inner ring by a caulking portion formed by plastically deforming an end portion of the small diameter step portion radially outward. In the wheel bearing device fixed in the axial direction with respect to the hub wheel, the double row rolling element row The outer side rolling element row is composed of tapered rollers, the inner side rolling element row is composed of balls, and the pitch circle diameter of the outer tapered roller row is larger than the pitch circle diameter of the inner side ball row. The diameter is set to be large, and the number of these tapered rollers and balls is set to be the same.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
FIG. 1 is a longitudinal sectional view showing a first embodiment of a wheel bearing device according to the present invention.
This wheel bearing device is for a drive wheel called the second generation, and includes a hub wheel 1 and a wheel bearing 2 fixed to the hub wheel 1.

  The hub wheel 1 integrally has a wheel mounting flange 3 for mounting a wheel (not shown) at one end portion on the outer side, and has a small diameter extending in the axial direction from the wheel mounting flange 3 to the outer periphery via a shoulder portion 1a. A step 1b is formed, and a serration (or spline) 1c for torque transmission is formed on the inner periphery. Hub bolts 3a are planted on the wheel mounting flange 3 at equal intervals in the circumferential direction.

  The wheel bearing 2 is press-fitted into the small-diameter step portion 1b through a predetermined shimiro while being in contact with the shoulder portion 1a of the hub wheel 1. This hub wheel 1 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 in the range of 58 to 64 HRC by induction hardening from the shoulder 1a to the small diameter step 1b. Has been cured. Thereby, it has sufficient mechanical strength with respect to the rotational bending load applied to the wheel mounting flange 3, and can improve the fretting resistance of the small-diameter step portion 1b serving as the fitting portion of the wheel bearing 2. it can.

  The wheel bearing 2 integrally has a vehicle body mounting flange 4c to be attached to a knuckle (not shown) constituting a suspension device on the outer periphery, and double row outer rolling surfaces 4a and 4b are formed on the inner periphery. The outer member 4, two inner races 5 and 6 each having outer circumferential surfaces 5a and 6a opposed to the outer circumferential rolling surfaces 4a and 4b in the double row, and both rolling surfaces 4a and 5a. A plurality of tapered rollers 9 and balls 10 are provided between 4b and 6a so as to be freely rollable via cages 7 and 8. Seals 11 and 12 are attached to the opening portion of the annular space formed between the outer member 4 and the two inner rings 5 and 6, leakage of grease sealed inside the bearing to the outside, and rainwater from the outside And dust are prevented from entering the bearing.

  The outer rolling surfaces 4 a and 5 a are formed in a tapered shape in line contact with the tapered roller 9, and the inner rolling surfaces 4 b and 6 a are formed in an arc shape in angular contact with the ball 10. . A large flange 5b for guiding the tapered roller 9 to the large diameter side of the inner rolling surface 5a of the inner ring 5 on the outer side and a small flange 5c for preventing the tapered roller 9 from falling off are formed on the small diameter side. Has been.

  The outer member 4 is formed of medium and high carbon steel containing 0.40 to 0.80 wt% of carbon such as S53C, and the double row outer rolling surfaces 4a and 4b have a surface hardness in the range of 58 to 64HRC by induction hardening. It has been cured. Further, the inner rings 5 and 6, the tapered rollers 9 and the balls 10 are made of high carbon chrome steel such as SUJ2, and are hardened in the range of 58 to 64 HRC up to the core part by quenching.

  Here, the pitch circle diameter PCDo of the 9 rows of the outer side tapered rollers is set to a larger diameter (PCDo> PCDi) than the pitch circle diameter PCDi of the 10 rows of the inner side balls. In this embodiment, since the tapered roller 9 is used for the outer side rolling element and the ball 10 is used for the inner side rolling element, the outer side tapered roller is used even if there is a difference in pitch circle diameters PCDo and PCDi. The number of rollers Zo in the nine rows and the number of balls Zi in the ten rows of balls on the inner side are set to be the same (Zo = Zi). Therefore, by setting the pitch circle diameter PCDo of the 9 rows of the outer side tapered rollers to be larger than the pitch circle diameter PCDi of the 10 rows of the inner side balls, the basic load rating of the outer side bearing row can be reduced compared to the inner side. It can be increased to improve stiffness and life. Also, by increasing the pitch circle diameter PCDo, the hub wheel 1 becomes thicker and the strength can be increased. In addition, the operating point distance of the double-row bearing is increased, and the overall bearing rigidity and life are improved. A wheel bearing device can be provided.

  FIG. 2 is a longitudinal sectional view showing a second embodiment of the wheel bearing device according to the present invention. This embodiment basically differs from the above-described embodiment only in the configuration of the hub wheel, and other parts having the same parts or the same functions are denoted by the same reference numerals and detailed description thereof is omitted. .

  This wheel bearing device is for a driven wheel called the third generation, and includes an outer member 4, a hub ring 13, and an inner ring 6 press-fitted into the small-diameter step portion 13 b of the hub ring 13. And a member 14. The hub wheel 13 is formed with an outer-side inner rolling surface 13a facing the outer-side outer rolling surface 4a and a small-diameter step portion 13b extending in the axial direction from the inner-rolling surface 13a. The inner ring 6 is press-fitted into the small-diameter step portion 13b via a predetermined scissors, and is fixed in the axial direction by a caulking portion 13c formed by plastically deforming an end portion of the small-diameter step portion 13b radially outward.

  Seals 15 and 12 are attached to the opening portion of the annular space formed between the outer member 4 and the hub ring 13 and the inner ring 6, leakage of grease sealed inside the bearing to the outside, and rainwater from the outside. And dust are prevented from entering the bearing.

  Further, the inner rolling surface 13a of the hub wheel 13 is formed in a tapered shape in line contact with the tapered roller 9, and a large collar 13d for guiding the tapered roller 9 is integrally formed on the larger diameter side of the inner rolling surface 13a. Is formed. Here, the cage 7 ′ is formed so as to prevent the tapered roller 9 from falling off inward in the radial direction. As a result, it is possible to eliminate the small punch that prevents the tapered roller 9 from dropping off on the small diameter side of the inner rolling surface 13a, thereby improving the workability of the hub wheel 13 and simplifying the assembly work and automating the assembly. And cost reduction can be achieved.

  The hub wheel 13 is made of medium and high carbon steel containing 0.40 to 0.80 wt% of carbon such as S53C, and extends from the seal land portion 3b in sliding contact with the seal 15 to the inner rolling surface 13a and the small diameter step portion 13b. The surface hardness is set to a range of 58 to 64 HRC by induction hardening. The caulking portion 13c is kept in the surface hardness after forging.

  Here, in the present embodiment, the pitch circle diameter PCDo of the outer side tapered roller 9 rows is set larger than the pitch circle diameter PCDi of the inner side ball 10 rows (PCDo> PCDi), as in the above-described embodiment. At the same time, the number of rollers Zo in the 9 rows of tapered rollers on the outer side is set to be the same as the number of balls Zi in the 10 rows of balls on the inner side (Zo = Zi). Accordingly, the basic load rating of the outer bearing row is increased as compared with the inner side, and the rigidity and life can be improved. Further, by setting the pitch circle diameter PCDo of the 9 rows of the outer side tapered rollers to be larger than the pitch circle diameter PCDi of the 10 rows of the inner side balls, the thickness of the hub wheel 1 is increased and the strength is increased. In addition, the working point distance of the double row bearing can be increased, and the overall bearing rigidity and life can be improved.

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

  The wheel bearing device according to the present invention can be applied to a wheel bearing device having a second or third generation structure regardless of whether it is for driving wheels or driven wheels.

It is a longitudinal section showing a 1st embodiment of a bearing device for wheels concerning the present invention. It is a longitudinal cross-sectional view which shows 2nd Embodiment of the wheel bearing apparatus which concerns on this invention. It is a longitudinal cross-sectional view which shows the conventional wheel bearing apparatus.

Explanation of symbols

1, 13 ······· Hub wheel 1a ··································································· ····· Wheel bearing 3 ··· Wheel mounting flange 3a ················· Hub bolt 3b ..... Outer members 4a, 4b ... Outer rolling surface 4c ... Car body mounting flanges 5, 6 ... Inner ring 5a, 6a, 13a .. Inner rolling surface 5b, 13d... Large bowl 5c... Small bowl 7, 7 ', 8. ··········································································································・ Inner member 50 ・ ・ ・ ・ ・ ・ ・ ・ ・ Hub wheel 5 0a, 51a ... Inner rolling surface 50b ... Small diameter step 51 ... Inner ring 52 ... Inner member 53 ... .... Outer members 53a, 53b ... Outer rolling surface 53c ... Car body mounting flange 54 ... Wheel mounting flange 55 ... ············································································· Retainer 59, 60 Pitch circle diameter of the ball row PCDo ············ Pitch circle diameter Zi of the outer side tapered roller row ····································· ... Number of rollers in outer tapered roller array

Claims (4)

An outer member integrally having a vehicle body mounting flange to be attached to the knuckle on the outer periphery, and a double row outer rolling surface formed on the inner periphery;
A hub wheel integrally having a wheel mounting flange for mounting a wheel at one end, a small diameter stepped portion formed on the outer periphery, and press-fitted into the small diameter stepped portion of the hub wheel, and the double row outer rolling on the outer periphery An inner member composed of at least one inner ring formed with an inner rolling surface facing the surface;
In a wheel bearing device comprising a double row rolling element row accommodated so as to roll freely between both rolling surfaces of the inner member and the outer member via a cage,
Of the double row rolling element rows, the outer side rolling element row is constituted by a tapered roller, the inner side rolling element row is constituted by a ball, and the pitch circle diameter of the outer tapered roller row is defined by an inner side. A wheel bearing device characterized in that the diameter is set larger than the pitch circle diameter of the ball row, and the number of the tapered rollers and the number of balls is set to be the same.   A tapered inner rolling surface is directly formed on the outer periphery of the hub wheel, and the small-diameter step portion extending in the axial direction from the inner rolling surface is formed, and the small-diameter step portion is formed on the small-diameter step portion via a predetermined shimiro. The wheel bearing device according to claim 1, wherein the inner ring is press-fitted.   A large hook for guiding the tapered roller is formed on the large diameter side of the inner rolling surface, and a cage for holding the tapered roller is formed to prevent the tapered roller from falling off in the radial direction. The wheel bearing device according to claim 2.   The wheel bearing device according to any one of claims 1 to 3, wherein the inner ring is fixed in an axial direction by a caulking portion formed by plastically deforming an end portion of the small diameter step portion radially outward.

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