JP2007239874A - Bearing device for wheel - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To simultaneously solve the conflicting problems of making a bearing device for a wheel lightweight, compact, and highly rigid, and to provide the bearing device for a wheel improved in strength and durability. <P>SOLUTION: In the bearing device for a wheel with a second generation structure equipped with double row rolling elements and in which inner rings 5 and 6 are fixed by swing caulking, a ball 9 is the rolling element on the outer side out of the double row rolling elements, and the rolling element on the inner side is a tapered roller 10, the basic load rating of row of the conical roller 10 on the inner side is set larger than the basic load rating of the row of the ball 9 on the inner side. Therefore, the rigidity of the portion of the row of the rolling element on the inner side becomes high, and the service life can be the same or longer even when the load applied to the row of the rolling element on the inner side becomes larger than the load applied to the row of the rolling element on the outer side. <P>COPYRIGHT: (C)2007,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.

  The wheel bearing device shown in FIG. 4 has a fourth generation structure that is lightweight and compact, and includes a hub wheel 50, a double row rolling bearing 51, and a constant velocity universal joint 52 that are unitized. The double row rolling bearing 51 includes an outer member 53, an inner member 54, and a plurality of balls 55 and tapered rollers 56 accommodated between the two members. 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 outer member 53 integrally has a vehicle body mounting flange 53c attached to a knuckle constituting a suspension device (not shown) on the outer periphery, and double row outer rolling surfaces 53a and 53b are formed on the inner periphery. Here, the diameter of the outer-side outer rolling surface 53a is set to be smaller than the diameter of the inner-side outer rolling surface 53b. On the other hand, the inner member 54 includes a hub wheel 50, an outer joint member 58, which will be described later, integrally formed with the hub wheel 50, and a separate inner ring 57 press-fitted into the outer joint member 58. Yes.

  The hub wheel 50 integrally has a wheel mounting flange 50b for mounting a wheel (not shown) at one end, and the outer side outer rolling surface 53a of the double row outer rolling surfaces 53a and 53b on the outer periphery. The inner race surface 50a is formed directly on the inner ring 57, and the inner race surface 57a on the outer circumference of the inner ring 57 is opposed to the inner race surface 53b on the inner side of the double row outer race surfaces 53a, 53b. Is formed.

  The constant velocity universal joint 52 has an outer joint member 58 composed of a cup-shaped mouth portion 59 and a shoulder portion 60 that forms the bottom of the mouth portion 59, and the outer periphery of the outer joint member 58 has a curved shape. A track groove 58a is formed. The inner ring 57 is press-fitted into the outer diameter of the mouse portion 59 and is fixed in the axial direction by a retaining ring 61.

  A plurality of balls 55 are accommodated between the outer rolling surfaces of the outer member 53 and the inner member 54, and a plurality of tapered rollers 56 are accommodated between the inner rolling surfaces. Of the 55 rows and the 56 tapered rollers, the pitch circle diameter of the 55 outer balls is set smaller than the pitch circle diameter of the 56 inner tapered rollers. As a result, the basic rated load of the inner side rolling element row part to which a larger load is applied than the outer side rolling element row part is made larger than the basic rated load of the outer side rolling element row part. The lifetime of the row portions can be made substantially the same, and a design without waste can be made possible (see, for example, Patent Document 1).

  However, in such a wheel bearing device, since the inner ring 57 is fixed to the mouth portion 59 of the outer joint member 58, it is surely made compact in the axial direction. Not only does the outer diameter itself become large and hinders weight reduction, but it is not preferable due to a design change of peripheral parts such as a knuckle. As a solution to these problems, a wheel bearing device as shown in FIG. 5 is known.

  This wheel bearing device has a vehicle body mounting flange 62c integrally attached to a knuckle (not shown) on the outer periphery, and an outer member having double-row outer rolling surfaces 62a and 62b formed on the inner periphery. 62 and a wheel mounting flange 63 for mounting a wheel (not shown) at one end thereof are integrally formed and opposed to the outer-side outer rolling surface 62a of the double-row outer rolling surfaces 62a and 62b on the outer periphery. The inner raceway 64a, the hub wheel 64 formed with the small diameter step portion 64b extending in the axial direction from the inner raceway surface 64a, and the small diameter step portion 64b of the hub wheel 64, and are fitted on the outer side of the double row. Of the rolling surfaces 62a and 62b, an inner member 66 comprising an inner ring 65 formed with an inner rolling surface 65a facing the inner outer rolling surface 62b, and a double row accommodated between these rolling surfaces. Balls 67, 68 and these It is composed of a double row angular contact ball bearing having a retainer 69, 70 for holding the balls 67, 68 rollably.

  The inner ring 65 is fixed in the axial direction by a caulking portion 64c formed by plastically deforming the small-diameter stepped portion 64b of the hub wheel 64 radially outward. Seals 71 and 72 are attached to the opening portion of the annular space formed between the outer member 62 and the inner member 66, leakage of the lubricating grease sealed inside the bearing, and rainwater entering the bearing from the outside. And dust are prevented from entering.

Here, the pitch circle diameter D1 of the 67 rows of balls on the outer side is set larger than the pitch circle diameter D2 of the 68 rows of balls on the inner side. Along with this, the inner rolling surface 64a of the hub wheel 64 is expanded in diameter than the inner rolling surface 65a of the inner ring 65, and the outer rolling surface 62a on the outer side of the outer member 62 is also rolled on the inner side. The diameter is larger than that of the surface 62b. The outer side balls 67 are accommodated more than the inner side balls 68. As described above, by setting the pitch circle diameters D1 and D2 to D1> D2, the rigidity is improved not only when the vehicle is stationary but also when turning, and the life of the wheel bearing device can be extended. (For example, refer to Patent Document 2).
JP 11-91308 A JP 2004-108449 A

  In such a conventional wheel bearing device, the pitch circle diameter D1 of the outer row of the balls 67 is set larger than the pitch circle diameter D2 of the inner row of the balls 68. The running surface 64 a is larger in diameter than the inner rolling surface 65 a of the inner ring 65. As a result, the rigidity of the outer bearing row can be improved while avoiding an increase in size of the device, and the life of the wheel bearing device can be extended. However, the loads applied to the inner and outer rows are different from each other, and the load applied to the inner rolling element row part is generally larger than the load applied to the outer rolling element row part. is there. In this case, in this conventional wheel bearing device, the basic load rating of the inner side rolling element row portion is smaller than the basic load rating of the outer side rolling element row portion, resulting in a shorter life.

  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 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. Wheel bearings in which the inner ring is fixed in the axial direction with respect to the hub wheel by a crimped portion formed by plastically deforming an end portion of the small diameter step portion radially outward. In the device, the outer side rolling element of the double row rolling elements is a ball. With the rolling elements of the inner side is tapered rollers, basic rated load of the tapered roller rows of the inner side is set larger than the basic rated load of the ball train in the outer side.

  As described above, in the wheel bearing device of the second or third generation structure that includes the double row rolling elements and the inner ring is fixed by swing caulking, the outer side rolling element of the double row rolling elements is a ball. The inner side rolling element is a tapered roller, and the basic load rating of the inner side tapered roller train is set to be larger than the basic load rating of the outer side ball train. The rigidity of the rolling element row portion is increased, and the life can be made the same or longer even if the load applied to the inner rolling element row portion is larger than the load applied to the outer rolling element row portion. Therefore, it is possible to provide a wheel bearing device that can realize a design without waste and has improved strength and durability.

  Further, as in the invention described in claim 2, the pitch circle diameter of the inner side tapered roller row and the pitch circle diameter of the outer side ball row may be set to be the same. As described above, the pitch circle diameter of the inner side tapered roller row may be set smaller than the pitch circle diameter of the outer side ball row. In this case, the outer diameter on the inner side of the outer member can be set to a small diameter, the knuckle size can be reduced without reducing the basic load rating of the inner rolling element row, and the device can be made lighter and more compact. be able to.

  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 of the hub ring is straightened. It can be formed in any shape, and processability can be improved.

  Further, as in the invention according to claim 5, the outer side inner rolling surface is directly formed on the outer periphery of the hub wheel, and the small diameter step portion is formed on the inner side from the inner rolling surface, If the inner ring on the inner side is press-fitted into the small-diameter step portion through a predetermined scissors, the device can be further reduced in weight and size.

  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 rolling element that is rotatably accommodated between the inner member and both rolling surfaces of the outer member. In the wheel bearing device in which the inner ring is fixed in the axial direction with respect to the hub wheel by a caulking part formed by plastically deforming an end of the small diameter step part radially outward, the double row rolling element Of which the outer rolling element is a ball and the inner rolling element is a cone. In addition, since the basic load rating of the inner side tapered roller row is set larger than the basic load rating of the outer side ball row, the rigidity of the inner side rolling element row portion is increased. Even if the load applied to the inner side rolling element row portion is larger than the load applied to the outer side rolling element row portion, the life can be made the same or longer. Therefore, it is possible to provide a wheel bearing device that can realize a design without waste and has improved strength and durability.

  A hub wheel having a wheel mounting flange for mounting a wheel at one end and a small diameter step portion extending in the axial direction from the wheel mounting flange is formed on the outer periphery, and the hub wheel is press-fitted into the small diameter step portion of the hub wheel. A wheel bearing device comprising a wheel bearing, wherein the wheel bearing has a vehicle body mounting flange integrally attached to a knuckle on the outer periphery, and a double row outer rolling surface is formed on the inner periphery. An outer member, a pair of inner rings each having an inner rolling surface opposite to the outer surface of the double row on the outer periphery, and a double row of rolling elements accommodated between the rolling surfaces. In the wheel bearing device, comprising: a moving body, wherein the inner ring is fixed in an axial direction with respect to the hub wheel by a caulking portion formed by plastically deforming an end portion of the small diameter step portion radially outward. Out of the rolling elements in a row, the outer rolling element is a ball, and the inner With rolling elements is tapered rollers, basic rated load of the tapered roller rows of the inner side is set larger than the basic rated load of the ball train in 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 driven 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 a small-diameter step portion extending from the wheel mounting flange 3 in the axial direction via a shoulder portion 1a. 1b is formed. 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 abutted against the shoulder portion 1a of the hub wheel 1, and is formed by plastically deforming the end portion of the small-diameter step portion 1b. It is fixed in the axial direction by the fastening portion 1c. The hub wheel 1 is formed of medium 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 hardening from the shoulder portion 1a to the small diameter step portion 1b. It has been cured. The caulking portion 1c is kept in the surface hardness after forging. Thereby, it has sufficient mechanical strength with respect to the rotational bending load applied to the wheel mounting flange 3, and the fretting resistance of the small-diameter step portion 1b that becomes the fitting portion of the wheel bearing 2 is improved. The plastic working of the caulking portion 1c can be smoothly performed while preventing generation of minute cracks and the like.

  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. And a plurality of balls 9 and tapered rollers 10 accommodated in a freely rotatable manner via cages 7 and 8 between 4b and 6a. 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 side rolling surfaces 4 a and 5 a are formed in an arc shape that makes an angular contact with the ball 9, and the inner side rolling surfaces 4 b and 6 a are formed in a taper shape that makes a line contact with the tapered roller 10. A large flange 6b for guiding the tapered roller 10 to the large diameter side of the inner rolling surface 6a of the inner ring 6 on the inner side and a small flange 6c for preventing the tapered roller 10 from falling off are formed on the small diameter side. Has been.

  The outer member 4 is formed of medium 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 of 58 to 64 HRC by induction hardening. It has been cured. Further, the inner rings 5 and 6 and the balls 9 and the tapered rollers 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 by quenching.

  Here, in this embodiment, the pitch circle diameter PCD of the outer side ball 9 and the pitch circle diameter PCD of the inner side tapered roller 10 are set to be the same. Therefore, the rigidity of the inner side rolling element row portion is increased, the basic load rating is larger than the basic rated load of the outer side rolling element row portion, and the load applied to the inner side rolling element row portion is increased on the outer side. Even if it becomes larger than the load applied to the rolling element row portion, the life can be made the same or more. That is, it is possible to provide a wheel bearing device that can realize a design without waste and has improved strength and durability.

  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 squeeze, and is fixed in the axial direction by the crimping portion 1c.

  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. The hub wheel 13 is made of medium carbon steel containing 0.40 to 0.80 wt% of carbon such as S53C, and extends from the seal land portion where the seal 15 is slidably contacted 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.

  Here, in the present embodiment, the pitch circle diameter PCD of the 9 rows of balls on the outer side and the pitch circle diameter PCD of the 10 rows of tapered rollers on the inner side are set to be the same as in the embodiment described above. Therefore, while further reducing the weight and size of the device, the rigidity of the inner side rolling element row portion becomes higher, and the basic load rating becomes larger than the basic rated load of the outer side rolling element row portion. Even if the load applied to the rolling element row portion becomes larger than the load applied to the outer rolling element row portion, the service life can be the same or more.

  FIG. 3 is a longitudinal sectional view showing a third embodiment of the wheel bearing device according to the present invention. This embodiment is basically the same as the first embodiment (FIG. 1) described above, except that the pitch circle diameters of both rolling element rows are different, and the same parts or parts having the same function are the same. Reference numerals are assigned and detailed description is omitted.

  The wheel bearing device is for a driven wheel called a second generation, and includes a hub wheel 16 and a wheel bearing 17 fixed to the hub wheel 16. The hub wheel 16 integrally has a wheel mounting flange 3 at an end portion on the outer side, and a small-diameter step portion 16b extending in the axial direction from the wheel mounting flange 3 via a shoulder portion 16a is formed. The wheel bearing 17 is formed by being press-fitted into the small diameter step portion 16b through a predetermined shimiro while being in contact with the shoulder portion 16a of the hub wheel 16, and by plastically deforming the end portion of the small diameter step portion 16b. It is fixed in the axial direction by the crimped portion 1c.

  The wheel bearing 17 has a vehicle body mounting flange 4c integrally on the outer periphery, an outer member 18 having double rows of outer rolling surfaces 4a, 18a formed on the inner periphery, and outer rolling of these double rows on the outer periphery. Rolls between two inner rings 19 and 20 formed with inner rolling surfaces 19a and 20a facing the surfaces 4a and 18a, respectively, and cages 7 and 21 between the rolling surfaces 4a and 19a and 18a and 20a. A plurality of balls 9 and tapered rollers 10 accommodated freely are provided. Seals 22 and 23 are attached to the openings of the annular space formed between the outer member 18 and the two inner rings 19 and 20, 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 member 18 is formed of medium carbon steel containing carbon 0.40 to 0.80 wt% such as S53C, and the double row outer rolling surfaces 4a and 18a have a surface hardness in the range of 58 to 64HRC by induction hardening. It has been cured. Further, the inner rings 19 and 20 are made of high carbon chrome steel such as SUJ2, and are hardened in the range of 58 to 64 HRC to the core part by quenching.

  Here, in this embodiment, the pitch circle diameter PCDi of the 10 rows of inner side tapered rollers is set to be smaller than the pitch circle diameter PCDo of the 9 rows of balls on the outer side. As a result, the outer diameter D on the inner side of the outer member 18 can be set to a small diameter, the knuckle size can be reduced without reducing the basic load rating of the inner rolling element row, and the device is lighter and more compact. Can be achieved. Further, by increasing the thickness of the inner ring 19 on the outer side corresponding to the amount of expansion of the pitch circle diameter PCDo in the 9 rows of balls on the outer side, the hub wheel 16 can be used even if the pitch circle diameters PCDo and PCDi are different. The small-diameter step portion 16b can be formed in a straight shaft shape, and the workability 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 3rd 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. It is a longitudinal cross-sectional view which shows the other conventional wheel bearing apparatus.

Explanation of symbols

1, 13, 16 ... hub wheel 1a, 16a ... shoulder 1b, 13b, 16b ... small diameter step 1c ···································································· Wheel Bearing 3 ... Wheel mounting flange 3a ... Hub bolts 4, 18 ... Outer members 4a, 4b, 18a ... ... outside rolling surface 4c ... ... body mounting flanges 5, 6, 19, 20 ... ... inner rings 5a, 6a, 13a, 19a, 20a Inner rolling surface 6b ·············································································· ..... Retainer 9 ... No. 10 ... Tapered rollers 11, 12, 15, 22, 23 ... Seal 14 ... Inside Directional members 50, 64... Hub wheels 50a, 64a, 57a, 65a .. Inner rolling surfaces 50b, 63.・ ・ ・ ・ ・ ・ ・ ・ ・ ・ Double row rolling bearings 52 ・ ・ ・ ・ ・ ・ ・ ・ Constant velocity universal joints 53, 62 ・ ・ ・ ・ ・ ・... Outer members 53a, 53b, 62a, 62b ... Outer rolling surfaces 53c, 62c ... Car body mounting flanges 54,66 ... ..Inward members 55, 67, 68 ... Ball 56 ... Tapered rollers 57, 65 ... ... Inner ring 57a, 4a, 65a ... inner rolling surface 58 ... outer joint member 58a ... track groove 59・ ・ ・ ・ ・ ・ ・ ・ ・ ・ Mouse part 60 ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ Shoulder part 61 ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・· Retaining ring 64b ··········· Small diameter stepped portion 64c ··································· ················ Retainer 71, 72 ············································ ·················· Pitch circle diameter D2 of the ball on the outer side.・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ Pitch circle diameter PCDi ・ ・ ・ ・ ・ ・・ ・ ・ ・ ・ ・ Pitch circle diameter PCDo of inner side tapered roller ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ ・ Pitch circle diameter of outer side ball

Claims (5)

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;
A double row rolling element housed in a freely rolling manner between the rolling surfaces of the inner member and the outer member;
In the wheel bearing device in which the inner ring is fixed in the axial direction with respect to the hub wheel by a crimping portion formed by plastically deforming an end portion of the small diameter step portion radially outwardly,
Out of the double row rolling elements, the outer side rolling element is a ball, the inner side rolling element is a tapered roller, and the basic rated load of the inner side tapered roller row is the same as that of the outer side ball row. A wheel bearing device characterized by being set to be larger than a basic load rating.   The wheel bearing device according to claim 1, wherein a pitch circle diameter of the inner side tapered roller row and a pitch circle diameter of the outer side ball row are set to be the same.   The wheel bearing device according to claim 1, wherein a pitch circle diameter of the inner side tapered roller row is set to be smaller than a pitch circle diameter of the outer side ball row.   The wheel bearing device according to any one of claims 1 to 3, wherein a pair of inner rings are press-fitted into the small-diameter step portion of the hub ring, and the inner diameters of these inner rings are set to be the same.   An outer rolling surface on the outer side is directly formed on the outer periphery of the hub wheel, and the small-diameter step portion is formed on the inner side from the inner rolling surface, and the inner diameter is formed on the small-diameter step portion via a predetermined shimiro. The wheel bearing device according to claim 1, wherein the inner ring on the side is press-fitted.

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