JP2008169875A - 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 at the same time. <P>SOLUTION: The wheel bearing device comprises double-row tapered roller trains 9, 10. Pitch circle diameters of the double row tapered roller trains 9, 10 are set to be the same, a roller diameter do of the tapered roller train 9 on the outer side is set to be smaller than a roller diameter di of the tapered roller train 10 on the inner side, the roller number of the tapered roller train 9 on the outer side is set to be greater than the roller number of the tapered roller train on the inner side, and the length Li of the tapered roller train 10 on the inner side is set to be greater than the length Lo of the tapered roller train 9 on the outer side. This increases basic rated loads of both bearing trains without increasing the pitch circle diameter PCDo of the tapered roller train 9 on the outer side and improves the rigidity and life of the bearing while achieving 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.

  Among these, a wheel bearing device as shown in FIG. 3 is known. The wheel bearing device includes an inner member 52 including a hub wheel 50, an inner ring 51 press-fitted and fixed to the hub wheel 50, and an outer member 53 externally inserted into the inner member 52. Yes. 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 50 integrally has a wheel mounting flange 54 for attaching a wheel (not shown) to one end portion on the outer side, an outer side inner rolling surface 50a on the outer periphery, and the inner side rolling surface 50a. A small diameter step portion 50b extending in the axial direction, and a threaded portion 50c are formed at the end of the small diameter step portion 50b. Hub bolts 55 are planted on the wheel mounting flange 54 at equal intervals in the circumferential direction.

  The inner ring 51 has an inner-side inner rolling surface 51a formed on the outer periphery, is press-fitted into the small-diameter step portion 50a of the hub wheel 50, and is fixed to the shaft by a fixing nut 57 screwed into the screw portion 50c via a washer 56. It is fixed in the direction.

  The outer member 53 has a vehicle body mounting flange 53 c on the outer periphery, and is opposed to the outer rolling surface 53 a facing the inner rolling surface 50 a of the hub wheel 50 on the inner periphery and the inner rolling surface 51 a of the inner ring 51. The outer rolling surface 53b is integrally formed. The double rows of balls 60 and 61 are accommodated between the rolling surfaces via the cages 58 and 59 so as to freely roll, thereby constituting a so-called back-to-back type double row angular ball bearing.

Here, the pitch circle diameter D1 of the 60 rows of the outer side balls is set to be larger than the pitch circle diameter D2 of the 61 rows of the inner side balls. Accordingly, the inner side rolling surface 50a on the outer side is enlarged in diameter than the inner side rolling surface 51a on the inner side, and the outer side rolling surface 53a on the outer side of the outer member 53 is combined with the outer side rolling surface on the inner side. The diameter is larger than 53b. Then, the ball diameter of the outer 60 balls is set to be smaller than the ball diameter of the inner 61 balls, and the number of balls in the outer 60 balls is the same as the number of balls in the inner 61 balls. More than accommodated. As a result, the rigidity of the outer bearing row is improved not only when the vehicle is stationary but also when turning, and the life of the wheel bearing device can be extended (see, for example, Patent Document 1).
JP 2003-232343 A

  In such a conventional wheel bearing device, the pitch circle diameter D1 of the outer 60 rows of balls is set to be larger than the pitch circle diameter D2 of the inner balls 61, and the balls of the outer balls 60 are arranged. The diameter is set to be smaller than the ball diameter of the inner side ball 61 row, and accordingly, a larger number of outer side balls 60 are accommodated than the inner side ball 61. The rigidity is improved, and the life of the wheel bearing device can be extended. However, this not only shortens the life of the inner side bearing row relative to the outer side bearing row, but also the pitch circle diameter of the outer side ball row 60 as in the conventional wheel bearing device. It is good if D1 can be increased, but depending on the device, if the outer diameter of the outer member 53 is restricted due to the structure of the brake or the like, the pitch circle diameter D1 of the outer 60 rows of balls is increased to increase the number of balls. It is difficult to increase. Therefore, it has been a problem to improve the rigidity, strength and durability of the bearing while suppressing the space of the device.

  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. A hub wheel integrally having an outer member and a wheel mounting flange for mounting a wheel at one end, and having a small-diameter step portion extending in an axial direction from the wheel mounting flange on the outer periphery, and a small-diameter step of the hub wheel An inner member composed of at least one inner ring that is press-fitted into the outer periphery and has an inner rolling surface facing the outer rolling surface of the double row on the outer periphery, and both rolling of the inner member and the outer member In a wheel bearing device including a double row tapered roller row that is rotatably accommodated between the faces, the double row tapered roller row has the same pitch circle diameter, and the double row tapered roller row. Outer side tapered roller row has inner roller diameter The diameter of the tapered roller train is set to be smaller than the diameter of the tapered roller train, the number of rollers in the outer tapered roller train is set to be larger than the number of rollers in the inner tapered roller train, and the inner tapered roller is set. The roller length of the row is set longer than the roller length of the tapered roller row on the outer side.

  Thus, in the wheel bearing device of the second or third generation structure provided with the double row tapered roller row, the pitch circle diameter of the double row tapered roller row is set to be the same, and the double row tapered roller row The roller diameter of the outer side tapered roller train is set smaller than the roller diameter of the inner side tapered roller train, and the number of rollers in the outer side tapered roller train is larger than the number of rollers in the inner side tapered roller train. The roller length of the inner tapered roller row is set longer than the roller length of the outer tapered roller row, so that the pitch circle diameter of the outer tapered roller row is not increased. In addition, it is possible to provide a wheel bearing device that can increase the basic load rating of both bearing rows and improve the rigidity and life of the bearing while reducing the weight and size.

  Further, as in the invention according to claim 2, an outer side inner rolling surface is directly formed on the outer periphery of the hub wheel, and a small-diameter step portion extending in the axial direction from the inner rolling surface is formed, If an inner ring with an inner inner rolling surface formed on the outer periphery is press-fitted into the small-diameter step portion through a predetermined scissors, it will be possible to further reduce the weight and size, and to increase the strength and durability of the hub ring. Can be improved.

  Further, as in the invention described in claim 3, if the pair of inner rings are press-fitted into the small-diameter step portion of the hub wheel and the inner diameters of these inner rings are set to be the same, the small-diameter step portion has a straight shape. Since it can be integrally processed, the number of processing steps can be simplified and the cost can be reduced.

  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.・ It can be downsized and the strength and durability of the hub wheel can be improved.

  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 having a wheel mounting flange for attaching the hub wheel and having a small-diameter step portion extending in the axial direction from the wheel mounting flange 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 facing the outer rolling surface of the row, and is accommodated in a freely rollable manner between both rolling surfaces of the inner member and the outer member. In the wheel bearing device having the double-row tapered roller row, the pitch circle diameter of the double-row tapered roller row is set to be the same, and the outer-side tapered roller row of the double-row tapered roller row is set. Roller diameter is smaller than the roller diameter of the tapered roller array on the inner side The number of rollers in the outer side tapered roller train is set to be larger than the number of rollers in the inner side tapered roller train, and the roller length of the inner tapered roller train is set in the outer side. Because it is set longer than the roller length of the tapered roller row on the side, the basic load rating of both bearing rows can be increased without increasing the pitch circle diameter of the tapered roller row on the outer side, making it lightweight and compact. Thus, it is possible to provide a wheel bearing device in which the rigidity and the life of the bearing are improved while achieving a reduction in size.

  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. In a wheel bearing device including a double row tapered roller row that is rotatably accommodated between the faces, the double row tapered roller row has the same pitch circle diameter, and the double row tapered roller row. The roller diameter of the outer tapered roller row is the roller diameter of the inner tapered roller row Is set to a small diameter, the number of rollers of the outer side tapered roller train is set to be larger than the number of rollers of the inner side tapered roller train, and the roller length of the inner side tapered roller train is It is set longer than the roller length of the tapered roller row on the outer side.

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 driving wheel called a third generation, and includes an inner member 3 including a hub wheel 1 and an inner ring 2 press-fitted and fixed to the hub wheel 1, and the inner member 3. And an outer member 4 that is externally inserted.

  The hub wheel 1 integrally has a wheel mounting flange 5 for mounting a wheel (not shown) at one end portion on the outer side, an outer tapered inner rolling surface 1a on the outer periphery, and this inner rolling. A small-diameter step portion 1b extending in the axial direction from the surface 1a via the shoulder portion 1c is formed, and a serration (or spline) 1d for torque transmission is formed on the inner periphery. The inner ring 2 has an inner side tapered inner rolling surface 2a formed on the outer periphery, and is press-fitted into the small diameter step portion 1b via a predetermined shimoshiro, and the end portion of the small diameter step portion 1b is plastically outward in the radial direction. It is fixed in the axial direction by a caulking portion 1g formed by deformation. Hub bolts 6 are planted on the wheel mounting flange 5 at equal intervals in the circumferential direction.

  The hub wheel 1 is made of medium and high carbon steel containing 0.40 to 0.80 wt% of carbon, such as S53C, and has a small diameter step from a base portion 5a on the inner side of the wheel mounting flange 5 via an inner rolling surface 1a and a shoulder portion 1c. The surface hardness is hardened to a range of 58 to 64 HRC by induction hardening over the portion 1b. The caulking portion 1g is kept at the surface hardness after forging. Thereby, it has sufficient mechanical strength with respect to the rotational bending load applied to the wheel mounting flange 5, and the fretting resistance of the small-diameter step portion 1b which becomes the fitting portion of the inner ring 2 is improved, and caulking is performed. The plastic processing of the portion 1g can be performed smoothly by preventing the occurrence of minute cracks and the like.

  The outer member 4 integrally has a vehicle body mounting flange 4c to be attached to a knuckle (not shown) on the outer periphery, and the outer side outer rolling facing the inner rolling surface 1a of the hub wheel 1 on the inner circumference. An inner side outer rolling surface 4b that faces the surface 4a and the inner rolling surface 2a of the inner ring 2 is formed. And the double-row tapered rollers 9 and 10 row are accommodated so that rolling is possible via the holder | retainers 7 and 8 between both rolling surfaces. Further, seals 11 and 12 are attached to the opening of the annular space formed between the outer member 4 and the inner member 3, and leakage of grease sealed inside the bearing and rainwater from the outside. And dust are prevented from entering the bearing.

  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 ring 2 and the tapered rollers 9 and 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.

  Inner rolling surfaces 1a and 2a of the hub wheel 1 and the inner ring 2 are formed in a taper shape in line contact with the tapered rollers 9 and 10, and a small diameter side (front) end surface 2d of the inner ring 2 is formed on the shoulder 1c of the hub wheel 1. A so-called back-to-back type double-row tapered roller bearing, which is abutted in a butt state, is formed. And the large collars 1e, 2b for guiding the tapered rollers 9, 10 to the large diameter side of the inner rolling surfaces 1a, 2a, and the small collar 1f for preventing the tapered rollers 9, 10 from falling off on the small diameter side, 2c is formed.

  Here, in this embodiment, the pitch circle diameter PCDo of the 9 rows of outer tapered rollers and the pitch circle diameter PCDi of the 10 rows of inner tapered rollers are set to be the same (PCDo = PCDi), and the outer cone The roller diameter do of the 9 rows of rollers is set to a smaller diameter (do <di) than the roller diameter di of the 10 rows of tapered rollers on the inner side, and the roller length Li of the 10 rows of tapered rollers on the inner side is set to the tapered rollers 9 on the outer side. It is set to be longer than the row roller length Lo (Li> Lo). Further, the number of rollers Zo in the 9 rows of outer tapered rollers is set to be larger than the number of rollers Zi in the 10 rows of tapered rollers on the inner side (Zo> Zi). As a result, the basic rated load of both bearing rows can be increased without increasing the pitch circle diameter PCDo of the 9 rows of tapered rollers on the outer side, the increase in the outer diameter of the outer member 4 can be suppressed, and the weight and size can be reduced. Thus, it is possible to provide a wheel bearing device in which the rigidity and the life of the bearing are improved while achieving a reduction in size.

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

  This wheel bearing device is for a driven wheel called a second generation, and includes a hub wheel 13 and a wheel bearing 14 fixed to the hub wheel 13. The hub wheel 13 integrally has a wheel mounting flange 5 at an end portion on the outer side, and a small-diameter step portion 13b extending in the axial direction from the wheel mounting flange 5 is formed on the outer periphery. The wheel bearing 14 is press-fitted into the small-diameter step portion 13b through a predetermined scissors.

  The wheel bearing 14 is press-fitted into the small-diameter step portion 13b through a predetermined shimiro while being abutted against the shoulder portion 13a of the hub wheel 13, and is formed by plastically deforming an end portion of the small-diameter step portion 13b. It is fixed in the axial direction by the fastening portion 1g. The hub wheel 13 is formed of medium and high carbon steel containing 0.40 to 0.80 wt% of carbon such as S53C, and the surface hardness is set to a range of 58 to 64 HRC by induction quenching from the shoulder portion 13a to the small diameter step portion 13b. It has been cured. Thereby, it has sufficient mechanical strength with respect to the rotational bending load applied to the wheel mounting flange 5, and the fretting resistance of the small-diameter step portion 13 b serving as the fitting portion of the wheel bearing 14 is improved.

  The wheel bearing 14 includes an outer member 4, two inner races 15, 2 each having inner race surfaces 15 a, 2 a facing the outer rows 4 a, 4 b of the double row on the outer circumference, and both races. Double-row tapered rollers 9 and 10 are provided between the surfaces 4a, 15a and 4b and 2a so as to be freely rollable via cages 7 and 8 respectively. Seals 12, 12 are attached to the opening of the annular space formed between the outer member 4 and the two inner rings 15, 2, leakage of grease sealed inside the bearing, and rainwater from the outside And dust are prevented from entering the bearing.

  The inner rolling surface 15 a of the outer ring 15 on the outer side is formed in a tapered shape that makes line contact with the tapered roller 9. And the so-called back-to-back type double row tapered roller bearing in which the small-diameter side (front) end faces 15d, 2d of the pair of inner rings 15, 2 are abutted in a butted state is constituted. Further, like the inner ring 2, a large flange 15b for guiding the tapered roller 9 and a small flange 15c for preventing the tapered roller 9 from falling off are formed on the large diameter side of the inner rolling surface 15a. Has been. Furthermore, the inner diameter of the inner ring 15 is set to be the same as the inner diameter of the inner ring 2 on the inner side. As a result, the small-diameter step portion 13b can be integrally processed in a straight shape, so that the number of processing steps can be simplified and the cost can be reduced. The inner ring 15 is made of high carbon chrome steel such as SUJ2 and is hardened in the range of 58 to 64 HRC to the core portion by quenching, like the inner ring 2 on the inner side.

  In this embodiment, as in the first embodiment described above, the pitch circle diameter PCDo of the 9 rows of outer side tapered rollers is the same as the pitch circle diameter PCDi of the 10 rows of inner tapered rollers (PCDo = PCDi). And the roller diameter do of the outer side tapered roller 9 row is set to be smaller than the roller diameter di of the inner side tapered roller 10 row (do <di), and the inner side tapered roller 10 row roller is set. The length Li is set to be longer than the roller length Lo of the 9 rows of tapered rollers on the outer side (Li> Lo). Further, with the diameter difference between the roller diameter do of the 9 rows of the outer side tapered rollers and the roller diameter di of the 10 rows of the inner side tapered rollers, the number of rollers Zo of the 9 rows of the outer side tapered rollers becomes the inner side tapered roller 10. More than the number of rollers Zi in the row is accommodated (Zo> Zi). As a result, the basic rated load of both bearing rows can be increased without increasing the pitch circle diameter PCDo of the 9 rows of tapered rollers on the outer side, the increase in the outer diameter of the outer member 4 can be suppressed, and the weight and size can be reduced. It is possible to improve the rigidity and life of the bearing while achieving a reduction in the size.

  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 constituted by double-row tapered roller bearings, regardless of whether 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, 2a, 15a ... inner rolling surface 1b, 13b ... small diameter Step 1c, 13a ... shoulder 1d ... serrations 1e, 2b, 15b ... Oiso 1f, 2c, 15c ... Gauge 1g ... Caulking part 2, 15 ... Inner ring 2d, 15d ······ Small diameter side end face 3 ···························· ... Outer members 4a, 4b ... Outer rolling surface 4c ... Body mounting flange 5 ... ..... Wheel mounting flange 5a ... · Base 6 ·························································································· ······································· Seal 14 ... hub wheels 50a, 51a ... inner rolling surface 50b ... small diameter step 50c ...・ ・ ・ ・ ・ ・ ・ ・ ・ ・ Threaded part 51 ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ Inner ring 52 ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ Inner member 53 ・· · · · · · · · · · Outer members 53a, 53b · · · Outer rolling surface 53c · · · · · · Body Mounting flange 54 ... Wheel mounting flange 55 ... ... Hub bolt 56 ... Washer 57 ... Fixing nuts 58, 59 ... ········································································· Tapered roller di ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ Inner side tapered roller diameter do ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ Outer side tapered roller Diameter D1 ············ Pitch circle diameter D2 of the outer side ball row ·························· Pitch circle of the inner side ball row Diameter PCDi ......... Pitch circle diameter PCDo of inner side tapered roller trains ... Do ... Pitch circle diameter Zi of outer side tapered roller trains・············································································ ......

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 having a wheel mounting flange for attaching a wheel to one end portion integrally, a small diameter step portion extending in the axial direction from the wheel mounting flange on the outer periphery, and a small diameter step portion of the hub wheel are press-fitted, An inner member composed of at least one inner ring formed with an inner rolling surface facing the outer rolling surface of the double row on the outer periphery;
In the wheel bearing device including the inner member and a double row tapered roller row accommodated in a freely rolling manner between both rolling surfaces of the outer member,
The pitch circle diameter of the double row tapered roller row is set to be the same, and the roller diameter of the outer side tapered roller row of the double row tapered roller row is set smaller than the roller diameter of the inner side tapered roller row. In addition, the number of rollers in the outer side tapered roller row is set to be larger than the number of rollers in the inner side tapered roller row, and the roller length of the inner side tapered roller row is set to the outer side cone. A wheel bearing device characterized in that it is set longer than the roller length of the roller train.   An outer side inner raceway surface is directly formed on the outer circumference of the hub wheel, and a small-diameter step portion extending in the axial direction from the inner raceway surface is formed, and this small-diameter step portion is formed on the outer circumference via a predetermined shimoshiro. The wheel bearing device according to claim 1, wherein an inner ring on which an inner rolling surface on the inner side is formed is press-fitted.   2. The wheel bearing device according to claim 1, wherein a pair of inner rings are press-fitted into a small-diameter step portion of the hub ring, and the inner diameters of these inner rings are set to be the same.   4. The wheel bearing device according to claim 1, wherein the inner ring is fixed in the axial direction by a caulking portion formed by plastically deforming an end portion of the small diameter step portion radially outward. 5.

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