JP2024120447A - Wheel bearing device - Google Patents

Abstract

[Problem] To provide a wheel bearing device capable of reducing bending moment applied to a hub bolt and suppressing a decrease in the safety margin of the wheel bearing device. [Solution] A wheel bearing device 1 includes an inner member composed of an outer member 24, a hub ring 31 having an inner raceway 29 and a wheel mounting flange 25, and an inner ring 28 having an inner raceway 30 on its outer diameter, and double rows of balls 32 rollably accommodated between the raceway surfaces of the inner member and the outer member 24, in which the wheel mounting flange 25 has a bolt mounting hole 25b into which a hub bolt 35 is inserted, and the outer end surface of the wheel mounting flange 25 is inclined toward the outer end surface at an inclination angle θ1 with respect to a bottom wall portion 53 of a brake rotor 36, and when the outer end surface of the wheel mounting flange 25 is inclined, an inclination angle θ2 of the central axis of the bolt mounting hole 25b with respect to the axis O of the axle is smaller than the inclination angle θ1 of the wheel mounting flange 25 with respect to the bottom wall portion 53 of the brake rotor 36. [Selected Figure] Figure 5

Description

The present invention relates to a wheel bearing device.

A wheel bearing device that supports a wheel so that it can rotate freely is known. In the wheel bearing device, an inner member is placed inside an outer member, and a rolling member is interposed between the raceway surfaces of the outer member and the inner member. In this way, the wheel bearing device forms a rolling bearing structure, allowing the wheel attached to the inner member to rotate freely.

The inner member is provided with a wheel mounting flange at its outer end and a cylindrical small diameter step at its inner end. The brake rotor is fixed to the wheel mounting flange with a hub bolt (see, for example, Patent Document 1).

Patent No. 4658028

The wheel mounting flange and the mounting surface of the brake rotor are fixed by fastening the hub bolts and nuts, but if the precision of the wheel mounting flange surface is poor, the mounting surface of the brake rotor, which has a lower rigidity value compared to the wheel mounting flange, will deform. When the mounting surface of the brake rotor deforms, the distance between the surface of the brake rotor that comes into sliding contact with the brake pads and the brake rotor becomes uneven, which can result in surface wobble.

When surface wobble occurs, it causes vibration during braking (brake judder) and uneven wear of the brake rotor. Brake judder is an unpleasant vibration for the driver, so it needed to be suppressed.

With regard to the precision of the wheel mounting flange surface, the wheel mounting flange surface could tilt in the opposite direction to the brake rotor mounting surface due to deformation during heat treatment after turning or when the hub bolts were pressed in after assembly. Also, to prevent deterioration of the precision of the wheel mounting flange surface of the finished product, the wheel mounting flange surface was sometimes turned again after heat treatment but before the bearing was assembled, but if the desired precision was still not obtained, it was necessary to turn the wheel mounting flange surface after the bearing was assembled.

After the manufacturing process, the wheel mounting flange surface falls to the side opposite the mounting surface of the brake rotor, so that the brake rotor and wheel mounting flange surface come into contact on the inner diameter side. At this time, the brake rotor and wheel mounting flange surface are separated on the outer diameter side near the hub bolt. This can cause the mounting surface of the brake rotor, which has a low rigidity value, to deform when the nut is fastened to the hub bolt. This deformation can cause the distance between the brake rotor and the surface of the brake rotor that comes into sliding contact with the brake pad to become uneven, which can result in surface runout.

As a result, the wheel mounting flange was sometimes tilted toward the brake rotor relative to the abutment surface of the brake rotor. When machining hub bolt holes and tapped holes on the flange surface of the wheel mounting flange, these were done before tilting the wheel mounting flange toward the brake rotor relative to the abutment surface of the brake rotor. In this case, the hub bolt holes and tapped holes are tilted toward the inner diameter relative to the hub flange surface to match the inclination of the flange surface. The hub bolt holes and tapped holes are formed perpendicular to the hub flange surface, but with the conventional inclination angle of the hub flange surface, a decrease in the retention ability of the hub bolt holes and tapped holes was acceptable.

However, in recent years, as vehicles have become larger, wheel bearing devices have also become larger, which can lead to a larger inclination angle of the hub flange surface. If the inclination angle becomes larger, bending stress is applied to the hub bolts and wheel bolts at the time of tightening due to the stress that tries to make them parallel to the axis when the wheel nuts and wheel bolts are tightened.

The present invention was made in consideration of the above circumstances, and aims to provide a wheel bearing device that can reduce the bending moment applied to the hub bolt and prevent a decrease in the safety margin of the wheel bearing device.

The first invention relates to a bearing comprising an outer member having a double row outer raceway surface on an inner circumference thereof,
an inner member including a hub wheel having an inner raceway surface and a wheel mounting flange, and a raceway surface forming member connected to the hub wheel and having an inner raceway surface on an outer diameter thereof;
A wheel bearing device comprising: a double row of rolling elements rollably accommodated between the raceway surfaces of the inner member and the outer member,
The wheel mounting flange has a bolt hole for inserting a bolt,
The outer end surface of the wheel mounting flange is inclined toward the outer end surface with an inclination angle θ1 relative to the abutment surface of the brake rotor, and when the outer end surface of the wheel mounting flange is inclined, the inclination angle θ2 of the central axis of the bolt hole relative to the axial direction is smaller than the inclination angle θ1 of the outer end surface of the wheel mounting flange with respect to the abutment surface of the brake rotor.

According to the present invention, by making the inclination angle of the central axis of the bolt hole relative to the axial direction smaller than the inclination angle of the wheel mounting flange relative to the abutment surface of the brake rotor, the bending moment acting on the hub bolt when the hub bolt is fastened can be reduced, and the deterioration of the safety margin of the wheel bearing device can be suppressed.

1 is a cross-sectional view showing an overall configuration of a wheel bearing device according to an embodiment; 1 is a cross-sectional view showing a wheel bearing device and a brake rotor according to an embodiment; 1 is a cross-sectional view of a wheel bearing assembly and brake rotor having a modified wheel mounting flange in one embodiment; 1 is a cross-sectional view showing a wheel bearing device having a wheel mounting flange with a tilt angle set and a brake rotor according to an embodiment; 1A is an enlarged cross-sectional view showing a wheel mounting flange having an inclination angle set in an embodiment, in which (A) is a diagram showing a case where the inclination angle θ2 of the bolt mounting hole is greater than 0', and (B) is a diagram showing a case where the inclination angle θ2 of the bolt mounting hole is 0'. 1A is an enlarged cross-sectional view showing a wheel mounting flange having an inclination angle set in an embodiment, in which (A) is a diagram showing a case where the inclination angle θ2 of the bolt fastening hole is greater than 0', and (B) is a diagram showing a case where the inclination angle θ2 of the bolt fastening hole is 0'. 11 is a cross-sectional view showing a wheel bearing device placed on a base when measuring the inclination angle of the wheel mounting flange according to one embodiment. FIG. 10 is a cross-sectional view showing a hub wheel placed on a base when measuring the inclination angle of a wheel mounting flange according to one embodiment. FIG. FIG. 6 is a cross-sectional view of an upper portion of a wheel bearing device according to a second embodiment.

Below, a wheel bearing device 1, which is a first embodiment of the wheel bearing device, will be described with reference to Figures 1 and 2. In the following description, the inner side refers to the vehicle body side of the wheel bearing device 1 when it is attached to the vehicle body, and the outer side refers to the wheel side of the wheel bearing device 1 when it is attached to the vehicle body.

The wheel bearing device 1 of the embodiment shown in Figure 1 includes an outer member 24 having double row raceway surfaces 21, 22 integrally provided on the inner circumference and a vehicle body mounting flange 23 integrally provided on the outer circumference, a hub ring 31 having a raceway surface 29 facing the wheel mounting flange 25 and the raceway surface 21, an inner member composed of an inner ring 28 which is a raceway surface forming member pressed into the outer diameter of the cylindrical small diameter step 31a of the hub ring 31, balls 32 which are double row rolling elements interposed between the respective raceway surfaces of the outer member 24 and the hub ring 31, and a cage 33 which is interposed between the hub ring 31 and the outer member 24 and supports a plurality of balls 32 which are double row rolling elements at equal intervals in the circumferential direction in each row. A raceway surface 30 which faces the raceway surface 22 of the outer member 24 is formed on the outer diameter of the inner ring 28 which is a raceway surface forming member. In addition, the raceway surface 29 that faces the outer raceway surface 21 is directly formed on the outer diameter of the hub wheel 31.

Seals 34 are attached to both ends of the inner ring 28 and the outer member 24 to prevent the intrusion of foreign matter from the outside and the leakage of the grease filled inside. Hub bolts 35 for fixing the wheels are attached at equally spaced positions in the circumferential direction of the wheel mounting flange 25 of the hub wheel 31. A brake rotor 36 is fixed to the wheel mounting flange 25 of the hub wheel 31 by the hub bolts 35. Furthermore, the vehicle suspension is attached to the vehicle body mounting flange 23 of the outer member 24 via a knuckle (not shown).

The hub wheel 31 supports a vehicle wheel (not shown) so that it can rotate freely. The hub wheel 31 is formed in a roughly cylindrical shape and is made of medium to high carbon steel, such as S53C. The inner end of the hub wheel 31 is provided with a small diameter step 31a, which is a reduced diameter on the outer circumferential surface. The outer end of the hub wheel 31 is integrally provided with a wheel mounting flange 25. Hub bolts 35 for fastening the hub wheel 31 to the brake rotor 36 are press-fitted into the wheel mounting flange 25.

The inner ring 28 is press-fitted into the small diameter step 31a of the hub wheel 31. The outer peripheral surface of the inner ring 28 is provided with a raceway surface 30 that faces the raceway surface 22 on the outer side.

The multiple balls 32, which are rolling bodies, are held by a cage 33. The row of inner balls 32 is rollably sandwiched between the raceway surface 30 of the inner ring 28 and the inner raceway surface 22 of the outer member 24. The row of outer balls 32 is rollably sandwiched between the raceway surface 29 of the hub ring 31 and the outer raceway surface 21 of the outer member 24. In other words, the row of inner balls 32 and the row of outer balls 32 are rollably accommodated between the raceway surfaces of the outer member 24 and the inner member. The outer member 24 rotatably supports the hub ring 31 and the inner ring 28 via the row of inner balls 32 and the row of outer balls 32.

In the wheel bearing device 1, a double-row angular ball bearing is formed by the outer member 24, the inner members, hub wheel 31 and inner ring 28, a row of balls 32 on the inner side, and a row of balls 32 on the outer side. Note that the wheel bearing device 1 may be formed as a double-row tapered roller bearing instead of a double-row angular ball bearing.

A short cylindrical pilot portion 41 is provided on the outer end surface 25a (the outer end surface) of the wheel mounting flange 25 of the hub wheel 31, to which a wheel (not shown) and a brake rotor 36 are attached. The pilot portion 41 is made up of a first portion 41a and a second portion 41b, with the wheel fitted onto the first portion 41a and the brake rotor 36 fitted onto the second portion 41b. The wheel mounting flange 25 of the hub wheel 31 is provided with a bolt mounting hole 25b, and a hub bolt 35 for fixing the wheel and the brake rotor 36 to the wheel mounting flange 25 is fitted into the bolt mounting hole 25b.

The brake rotor 36 has a disk portion 51 that contacts a brake pad (not shown) supported by a brake caliper, and a hat portion 52 that is recessed from the inner diameter end of the disk portion 51 toward the outer side. The disk portion 51 and the hat portion 52 are integrally formed.

The hat portion 52 is composed of a bottom wall portion 53 extending in the radial direction and an outer peripheral portion 54 connected to the outer peripheral edge of the bottom wall portion 53 and having a cylindrical inner diameter surface, and defines a cylindrical hollow region centered on the axis O. The bottom wall portion 53 corresponds to an inner diameter region located on the inner diameter side of the outer peripheral portion 54. The disk portion 51 corresponds to an outer diameter region located on the outer diameter side of the outer peripheral portion 54.

The bottom wall portion 53 of the hat portion 52 has a plurality of through holes, and the above-mentioned hub bolt 35 passes through the bolt mounting hole 25b of the wheel mounting flange 25 and through these through holes. As shown in FIG. 2, the maximum outer diameter of the wheel mounting flange 25 is smaller than the diameter of the outer periphery 54 of the disk portion 51.

A nut 37 is screwed onto the tip of the hub bolt 35 that passes through the bolt mounting hole 25b of the wheel mounting flange 25 and the through hole. By tightening the nut 37, the inner abutment surface of the bottom wall portion 53 and the outer end surface 25a of the wheel mounting flange 25 are in close contact with each other. If the outer end surface 25a of the wheel mounting flange 25 is tilted to the opposite side of the brake rotor 36 before tightening the nut 37, a gap of angle θ0 is generated between the wheel mounting flange 25 and the brake rotor 36 as shown in FIG. 3. When the nut 37 is tightened in this state, the brake rotor 36, which has a relatively low rigidity, moves and deforms toward the outer end surface 25a of the wheel mounting flange 25. This causes the gap between the disk portion 51 of the brake rotor 36 and the brake pad to become uneven, causing brake judder.

Therefore, as shown in FIG. 4, the wheel mounting flange 25 is inclined toward the outer side. That is, the outer end surface 25a forming the hub flange surface of the wheel mounting flange 25 is formed so as to be inclined toward the outer end surface 25a side with respect to the bottom wall portion 53, which is the abutment surface of the brake rotor 36, at an inclination angle θ1. Here, the inclination angle of the outer end surface 25a with respect to the bottom wall portion 53 is θ1. The inclination angle θ1 is the relative inclination angle of the outer end surface 25a with respect to the bottom wall portion 53. In this embodiment, since the bottom wall portion 53 is positioned so as to be perpendicular to the axis O direction when mounted, in other words, the inclination angle θ1 is the inclination angle with respect to a straight line perpendicular to the axis O. Note that the bottom wall portion 53 may not be perpendicular to the axis O direction when mounted, in which case the inclination angle is relative to the bottom wall portion 53, and is larger or smaller than the angle with the straight line perpendicular to the axis O direction.

In one embodiment of the present invention, the inclination angle θ2 of the bolt mounting hole 25b, which is a bolt hole, is smaller than the inclination angle θ1. The inclination angle θ2 is the relative inclination angle of the central axis O2 of the bolt mounting hole 25b with respect to the axis O direction. In other words, the bolt mounting hole 25b is formed at an angle inclined by the inclination angle θ2 with respect to the outer peripheral surface of the pilot portion 41, which is formed parallel to the axis O.

The inclination angle θ2 is set to be equal to or larger than 0° and smaller than 20′.
5A, the inclination angle θ1 of the outer end face 25a with respect to the bottom wall portion 53 is set to about 20' to 30', and therefore the inclination angle θ2 is smaller than the inclination angle θ1. In other words, the inclination angle θ2 being 0° or more and smaller than 20' means that the difference in axial position between the outer diameter side end P1 and the inner diameter side end P2 of the outer end face 25a is 0.08 mm or less. With this configuration, the bending moment acting on the hub bolt 35 is reduced when the hub wheel 31 and the brake rotor 36 are fastened by the hub bolt 35.

Also, as shown in FIG. 5B, the inclination angle θ2 may be 0°. When the inclination angle θ2 is 0°, it is parallel to the axis O of the axle. With this configuration, the axial direction of the bolt mounting hole 25b is parallel to the axis, so when the hub bolt 35 is pressed into the bolt mounting hole 25b and the hub wheel 31 and the brake rotor 36 are fastened by the hub bolt 35, no bending moment is applied. Therefore, the stress on the hub bolt 35 is reduced, the distance between the disk portion 51 of the brake rotor 36 and the brake pad is kept uniform, and the occurrence of brake judder can be suppressed. Furthermore, by reducing the stress on the hub bolt 35, the deterioration of the safety margin of the wheel bearing device 1 can be suppressed.

As another embodiment, as shown in FIG. 6, a bolt fastening hole 25d may be formed instead of the bolt mounting hole 25b. The bolt fastening hole 25d has a female thread on its inner surface and is fixed by fastening a wheel bolt (not shown).

As shown in FIG. 6, the inclination angle θ2 of the bolt fastening hole 25d, which is a bolt hole for a wheel bolt, is smaller than the inclination angle θ1. The inclination angle θ2 is the relative inclination angle of the central axis O2 of the bolt fastening hole 25d with respect to the axis line O of the axle.

The inclination angle θ2 is set to be equal to or larger than 0° and smaller than 20′.
6A, the inclination angle θ1 of the outer end face 25a with respect to the bottom wall portion 53 is set to about 20' to 30', and therefore the inclination angle θ2 is smaller than the inclination angle θ1. In other words, the inclination angle θ2 being 0° or more and smaller than 20' means that the difference in axial position between the outer diameter side end P1 and the inner diameter side end P2 of the outer end face 25a is 0.08 mm or less. With this configuration, the bending moment applied to the wheel bolt is reduced when the hub wheel 31 and the brake rotor 36 are fastened by the wheel bolt.

Also, as shown in FIG. 6(B), the inclination angle θ2 may be 0°. When the inclination angle θ2 is 0°, it is parallel to the axis O of the axle. With this configuration, the axial direction of the bolt fastening hole 25d is parallel to the axis, so that when the wheel bolt is screwed into the bolt fastening hole 25d and the hub wheel 31 and the brake rotor 36 are fastened by the wheel bolt, no bending moment is applied. Therefore, the stress on the wheel bolt is reduced, the distance between the disk portion 51 of the brake rotor 36 and the brake pad is kept uniform, and the occurrence of brake judder can be suppressed. Furthermore, by reducing the stress on the wheel bolt, the deterioration of the safety margin of the wheel bearing device 1 can be suppressed.

Next, a method for measuring the inclination angle θ1 of the outer end surface 25a with respect to the bottom wall portion 53 will be described.
7 , when measuring the inclination angle θ1 in an assembled state of the wheel bearing device 1, the wheel bearing device 1 is placed with its inner end face facing downward on the pedestal 61. The pedestal 61 includes an outer edge portion 63 that protrudes upward from the recessed portion 62 and supports the vehicle body mounting flange 23.
The positions of two arbitrary points on the outer end surface 25a of the wheel mounting flange 25, which is the upper surface when the wheel bearing device 1 is placed on the pedestal 61, are measured. The further apart the arbitrary two points are, the higher the measurement accuracy of the inclination is, so it is preferable that the radial positions of the wheel bearing device are far apart. For example, one measurement point is set to the outer diameter side end P1, and the other measurement point is set to the inner diameter side end P2 where the R surface provided at the connection point with the pilot portion 41 ends. This makes it possible to accurately measure the inclination angle θ1 when the wheel bearing device 1 is in an assembled state. In addition, the inclination angle θ1 can be measured before shipping without disassembling the wheel bearing device 1.

8 , when measuring the inclination angle θ1, the hub wheel 31 may be placed with its inner end face facing downward on the pedestal 61. The pedestal 61 protrudes upward from the recess 62 and has an outer edge portion 63 that supports the outer end face of the small diameter step portion 31 a of the hub wheel 31.
The positions of any two points on the outer end surface 25a of the wheel mounting flange 25, which becomes the upper surface when the hub wheel 31 is placed on the pedestal 61, are measured. The further apart the any two points are, the higher the accuracy of measuring the inclination, so it is desirable that the two points are far apart in the radial direction of the wheel bearing device 1. For example, one measurement point is set at the outer diameter side end P1, and the other measurement point is set at the inner diameter side end P2 where the R surface provided at the connection point with the pilot portion 41 ends. This makes it possible to accurately measure the inclination angle θ1 during the manufacture of the hub wheel 31.

As described above, the wheel bearing device 1 includes an inner member composed of an outer member 24 having double row outer raceway surfaces 21, 22 on its inner circumference, a hub wheel 31 having an inner raceway surface 29 and a wheel mounting flange 25, and an inner ring 28 connected to the hub wheel 31 and having an inner raceway surface 30 on its outer diameter, and balls 32 which are double row rolling elements housed between the raceway surfaces of the inner member and the outer member 24 so as to be able to roll freely, wherein the wheel mounting flange 25 has bolt mounting holes 25b which are bolt holes through which hub bolts 35 are inserted, the wheel mounting flange 25 is inclined relative to the bottom wall portion 53 which is the contact surface of the brake rotor 36, and when the wheel mounting flange 25 is inclined, the inclination angle θ2 of the bolt mounting holes 25b relative to the axis O of the axle is smaller than the inclination angle θ1 of the wheel mounting flange 25 relative to the bottom wall portion 53 of the brake rotor 36.
With this configuration, when the hub wheel 31 and the brake rotor 36 are fastened together by the hub bolt 35, the bending moment applied to the hub bolt 35 is reduced.

Furthermore, when the outer end face of the wheel mounting flange 25 is inclined, the difference in axial position between the outer diameter side end P1 and the inner diameter side end P2 of the outer end face 25a of the flange is 0.08 mm or less.
With this configuration, when the hub wheel 31 and the brake rotor 36 are fastened together by the hub bolt 35, the bending moment applied to the hub bolt 35 is reduced.

In addition, the outer end surface of the wheel mounting flange 25 is inclined toward the outer end surface at an inclination angle θ1 relative to the bottom wall portion 53 of the brake rotor 36, and when the outer end surface of the wheel mounting flange 25 is inclined, it is desirable that the inclination angle θ2 of the central axis O2 of the bolt mounting hole 25b relative to the axial direction be less than or equal to 1/2 the inclination angle θ1 of the wheel mounting flange 25 relative to the bottom wall portion 53 of the brake rotor.
With this configuration, when the hub wheel 31 and the brake rotor 36 are fastened together by the hub bolt 35, the bending moment applied to the hub bolt 35 is reduced.

In addition, the outer end surface of the wheel mounting flange 25 is inclined toward the outer end surface at an inclination angle θ1 relative to the bottom wall portion 53 of the brake rotor 36, and when the outer end surface of the wheel mounting flange 25 is inclined, the inclination angle of the central axis O2 of the bolt mounting hole 25b is 0 degrees.
With this configuration, stress on the hub bolts 35 is reduced, the distance between the disc portion 51 of the brake rotor 36 and the brake pads is kept uniform, and the occurrence of brake judder can be suppressed.

In another embodiment, instead of the inner ring 28, a CVJ outer joint member 61 having a raceway surface on its outer diameter may be used as the raceway surface forming member. As shown in FIG. 9, a raceway surface 62 that faces the raceway surface 22 is formed on the outer diameter of the outer joint member 61. The outer joint member 61 is composed of a stem portion 63 and a mouth portion 64, and the raceway surface 62 is provided on the outer diameter of the outer end portion of the mouth portion 64. The outer peripheral surface of the stem portion 63 and the inner diameter of the hub wheel 31 are fixed to be non-rotatable by a spline fit.

The wheel mounting flange 25 of the hub wheel 31 is provided with a bolt mounting hole 25b, and the hub bolt 35 for fixing the wheel and the brake rotor 36 to the wheel mounting flange 25 is mounted in the bolt mounting hole 25b.

In this embodiment, the wheel bearing device 1 is configured as a wheel bearing device 1 of a third-generation structure in which the inner rolling surfaces 30 of the row of outer balls 32 are formed on the outer periphery of the hub wheel 31, but the present invention is not limited to this. For example, the present invention may be a second-generation structure in which a pair of inner rings are press-fitted and fixed to the hub wheel 31.

REFERENCE SIGNS LIST 1 Wheel bearing device 21 Raceway surface 22 Raceway surface 24 Outer member 25 Wheel mounting flange 28 Inner ring 29 Raceway surface 30 Raceway surface 31 Hub ring 31a Small diameter step portion 32 Ball (rolling element)
33 Cage 35 Hub bolt 36 Brake rotor 37 Nut 51 Disk portion 52 Hat portion 53 Bottom wall portion

Claims (4)

an outer member having a double row outer raceway surface on an inner periphery thereof;
an inner member including a hub wheel having an inner raceway surface and a wheel mounting flange, and a raceway surface forming member connected to the hub wheel and having an inner raceway surface on an outer diameter thereof;
A wheel bearing device comprising: a double row of rolling elements rollably accommodated between the raceway surfaces of the inner member and the outer member,
The wheel mounting flange has a bolt hole for inserting a bolt,
a wheel mounting flange having an outer end surface that is inclined toward the outer end surface with respect to the abutment surface of the brake rotor at an inclination angle θ1, and wherein, when the outer end surface of the wheel mounting flange is inclined, an inclination angle θ2 of the central axis of the bolt hole with respect to the axial direction is smaller than the inclination angle θ1 of the outer end surface of the wheel mounting flange with respect to the abutment surface of the brake rotor. The wheel bearing device according to claim 1, wherein, when the outer end surface of the wheel mounting flange is inclined, the difference in axial position between the inner diameter side and the outer diameter side of the outer end surface of the wheel mounting flange is 0.08 mm or less. an outer end surface of the wheel mounting flange is inclined toward the outer end surface with respect to a contact surface of the brake rotor at an inclination angle θ1;
3. The wheel bearing device according to claim 1, wherein when the outer end surface of the wheel mounting flange is inclined, an inclination angle θ2 of the central axis of the bolt hole with respect to the axle direction is less than or equal to half an inclination angle θ1 of the outer end surface of the wheel mounting flange with respect to the abutment surface of the brake rotor. an outer end surface of the wheel mounting flange is inclined toward the outer end surface with respect to a contact surface of the brake rotor at an inclination angle θ1;
3. The wheel bearing device according to claim 1, wherein an inclination angle θ2 of the central axis of the bolt hole is 0 degrees when the outer end surface of the wheel mounting flange is inclined.

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