JP5636977B2 - Wheel bearing device - Google Patents

Description

  The present invention relates to a wheel bearing device, and more particularly to a wheel bearing device for attaching a hub bolt to a wheel mounting flange of a wheel of an automobile or the like.

  As a conventional wheel bearing device, an inner member rotatable around a central axis, an outer member arranged around the inner member, and interposed between the outer member and the inner member There are those provided with a double row rolling element (for example, Patent Document 1).

  The inner member includes a hub shaft and an inner ring, and is disposed rotatably on the central axis. The hub shaft has a wheel mounting flange on its outer peripheral surface, is connected to the drive shaft through a constant velocity universal joint so as to be able to transmit torque, and is nut-fastened. A hub bolt and a brake rotor are attached to the hub axle via a wheel mounting flange. The inner ring is attached to the end of the hub shaft on the vehicle body side.

  The outer member has a vehicle body mounting flange on the outer peripheral surface, and is attached to the vehicle body side via a knuckle of a suspension device.

  The double row rolling elements are made of steel balls and are held by a cage so as to be able to roll. The rolling elements of the wheel side row are between the inner peripheral surface of the outer member and the outer peripheral surface of the hub axle, and the rolling members of the vehicle body side row are between the inner peripheral surface of the outer member and the outer peripheral surface of the inner ring, respectively. Has been placed.

  With the above configuration, when torque is transmitted from the engine side of the vehicle to the hub shaft via the drive shaft, constant velocity universal joint, or the like, the hub shaft rotates together with the inner ring. Since the wheel is attached to the hub axle, torque from the engine side is also transmitted to the wheel, and the wheel rotates together with the hub axle.

  By the way, in this kind of wheel bearing apparatus, the bolt insertion hole which press-fits and inserts a hub bolt in the wheel mounting flange is provided. And it is known that if the pressure input of the hub bolt to the bolt insertion hole is large, the flange may be distorted and the rotational runout accuracy may deteriorate. In the invention described in Patent Document 1, the head of the hub bolt is engaged with the wheel mounting flange in a non-rotatable manner, and the hub bolt is press-fitted with an appropriate press-fitting allowance, thereby suppressing the vibration of the wheel mounting flange. ing.

JP 2001-191715 A

  However, according to the wheel bearing device shown in Patent Document 1, it is necessary to bring the engaging portion engaged with the head portion of the hub bolt close to the head portion of the hub bolt. It is practically difficult to accurately process the boundary portion between the hub bolt head and the surface in contact with the head in the press-fitting direction. Therefore, when the hub bolt is press-fitted, there is a problem that the center axis of the hub bolt may be inclined with respect to the direction perpendicular to the wheel mounting flange.

  Accordingly, an object of the present invention is to provide a wheel bearing device capable of suppressing the inclination of the wheel mounting bolt while suppressing the deformation of the wheel mounting flange due to the press-fitting of the wheel mounting bolt.

  In order to achieve the above object, the present invention has a bolt head portion and a bolt screw portion, and has a bolt press-fitting portion interposed between the bolt head portion and the bolt screw portion, for attaching a wheel. A wheel mounting bolt, a hub shaft on which a wheel mounting flange having a bolt insertion hole for inserting and inserting the bolt press-fitting portion of the wheel mounting bolt is formed, and a bearing that rotatably supports the hub shaft The bolt insertion hole of the wheel mounting flange has a bolt detent surface that prevents the wheel mounting bolt from rotating, and a bolt receiving surface that receives the bolt head of the wheel mounting bolt in the axial direction. And the bolt head of the wheel mounting bolt includes a bolt engaging surface that engages with the bolt detent surface, a bolt abutting surface that contacts the bolt receiving surface, and the bolt engaging surface. Interposed between the serial bolt abutment surface, to provide a wheel bearing device having a non-contact surface while being pressed does not contact the bolt detent surface and the bolt receiving surface into the bolt insertion hole.

  According to the present invention, it is possible to suppress the inclination of the wheel mounting bolt while suppressing the deformation of the wheel mounting flange due to the press-fitting of the wheel mounting bolt.

(A) And (b) is sectional drawing and side view shown in order to demonstrate the whole wheel bearing apparatus which concerns on embodiment of this invention. (A) shows a sectional view, and (b) shows a side view. (A) And (b) is sectional drawing and side view which show the attachment state to the wheel mounting flange of the wheel mounting bolt in the wheel bearing apparatus which concerns on embodiment of this invention. (A) shows a sectional view, and (b) shows a side view. (A) And (b) is the front view and side view shown in order to demonstrate the wheel mounting volt | bolt of the wheel bearing apparatus which concerns on embodiment of this invention. (A) shows a front view, and (b) shows a side view. The side view shown in order to demonstrate the modification of the wheel mounting bolt in the wheel bearing apparatus which concerns on embodiment of this invention. (A) And (b) is sectional drawing shown in order to demonstrate the modification of the wheel mounting flange in the wheel bearing apparatus which concerns on embodiment of this invention.

[Embodiment]
(Whole configuration of wheel bearing device)
1 (a) and 1 (b) show the entire wheel bearing device. 2 (a) and 2 (b) show the main part of the wheel bearing device. 3A and 3B show wheel mounting bolts. As shown in FIG. 1, the wheel bearing device 1 is roughly composed of a bearing 2 and a bolt mounting mechanism 3.

(Configuration of bearing 2)
As shown in FIGS. 1A and 1B, the bearing 2 includes an inner member 4 that can rotate around the central axis O, and an outer member 5 that is disposed on the outer periphery of the inner member 4. These are provided with double-row rolling elements 6 and 7 interposed between the outer member 5 and the inner member 4, and are disposed between a vehicle body (not shown) and a wheel (not shown). .

  The inner member 4 includes a hub shaft 8 and an inner ring 9, and is disposed on the central axis O so as to be rotatable.

  The hub shaft 8 has two body portions 8a and 8b having different outer diameters, and is connected to a drive shaft (not shown) through a constant velocity universal joint (not shown) or the like so as to be able to transmit torque. And the whole is formed of a substantially cylindrical shaped body made of, for example, medium carbon steel. The hub axle 8 is provided with a through hole 8c that opens in both directions along the central axis O. A serration 80c for connecting a stem (not shown) of a constant velocity universal joint is formed on the inner peripheral portion of the through hole 8c.

  The large-diameter trunk portion 8a has an inner rolling surface 80a on the outer peripheral surface for rolling the rolling elements 6 in the wheel side (left side in FIG. 1) of the double-row rolling elements 6 and 7, and the hub axle 8 It is arranged on the wheel side.

  The small-diameter trunk portion 8 b has an attachment surface 80 b for attaching the inner ring 9 on the outer peripheral surface, and is disposed on the vehicle body side (right side in FIG. 1) with respect to the trunk portion 8 a of the hub axle 8.

  On the other hand, the inner ring 9 has an inner rolling surface 9a for rolling the rolling elements 7 in the vehicle body side row among the double row rolling elements 6 and 7, and is attached to the mounting surface 80b of the small-diameter body portion 8b. Is formed by a substantially cylindrical shaped body made of, for example, a cold-rolled steel plate.

  The outer member 5 has outer rolling surfaces 5a and 5b for rolling the double-row rolling elements 6 and 7, respectively, and a knuckle (not shown) as a component of a suspension device (not shown) on the vehicle body side. ) And the whole is formed by a substantially cylindrical shaped body made of, for example, medium carbon steel that opens in both directions of the central axis O. The outer member 5 is integrally provided with an annular vehicle body mounting flange 5c protruding from the outer peripheral surface thereof. The vehicle body mounting flange 5c is provided with a plurality of bolt insertion holes 50c that are arranged in parallel in the circumferential direction and into which a knuckle bolt (not shown) is inserted.

(Configuration of rolling elements 6 and 7)
As shown in FIG. 1, the rolling elements 6 in one side row are made of steel balls and are disposed between the outer rolling surface 5 a of the outer member 5 and the inner rolling surface 80 a of the hub shaft 8. And a ball cage (not shown) so as to be able to roll. On the wheel side of the rolling element 6, a wheel side seal member 10 interposed between the inner peripheral surface of the outer member 5 and the outer peripheral surface of the hub shaft 8 is disposed.

  The rolling elements 7 in the other side row are made of steel balls, are disposed between the inner rolling surface 9a of the inner ring 9 and the outer rolling surface 5b of the outer member 5, and are provided with a ball cage (not shown). )) So that it can roll. On the vehicle body side of the rolling element 7, a vehicle body side seal member 11 interposed between the inner peripheral surface of the outer member 5 and the outer peripheral surface of the inner ring 9 is disposed.

(Configuration of bolt mounting mechanism 3)
As shown in FIGS. 2A and 2B, the bolt mounting mechanism 3 includes an annular wheel mounting flange 12 and a hub bolt 13 as a wheel mounting bolt for mounting a wheel together with the wheel mounting flange 12. And.

  The wheel mounting flange 12 is integrally provided on the outer peripheral surface of the large-diameter body portion 8a (shown in FIG. 1) of the hub shaft 8. The wheel mounting flange 12 is provided with a plurality (four in the present embodiment) of bolt insertion holes 12a that are juxtaposed in the circumferential direction and into which the hub bolts 13 are press-fitted and inserted.

Each of the bolt insertion holes 12a has a plurality of (six in this embodiment) bolt rotation prevention surfaces 120a and 6 that prevent the hub bolts 13 from rotating in contact with the outer peripheral surface of the hub bolt 13 at the bolt press-fitting side opening. A bolt receiving surface 121a for receiving a bolt head 13a (described later) in the axial direction, and a stepped surface 122a interposed between the bolt receiving surface 121a and the plurality of bolt detent surfaces 120a, from the press-fitting direction of the hub bolt 13 When viewed, it is formed by a step-shaped recess having a substantially regular hexagonal opening surface. A serration 123a is formed on a portion of the inner peripheral surface of the bolt insertion hole 12a adjacent to the axial direction of the bolt press-fitting side opening. Bolt receiving surface 121a is formed in an annular shape, the maximum outer diameter dimension is smaller than the minimum distance between the axis O ₁ and the bolt detent surface 120a of the bolt insertion hole 12a.

A plurality of bolts detent surface 120a are each formed so as to be inclined with respect to the circumferential direction of the axis O ₁ of the bolt insertion holes 12a, parallel along a substantially regular hexagonal opening peripheral edge of the bolt insertion holes 12a, It arrange | positions at the vehicle body side of the bolt press-fit side opening part in the bolt insertion hole 12a.

Bolt receiving surface 121a is formed in a flat bolt seating surface formed in an annular shape along the axis O ₁ around the bolt insertion holes 12a, it is arranged on the wheel side of the bolt press-fitting-side opening of the bolt insertion hole 12a Yes. Thereby, when the hub bolt 13 is press-fitted into the bolt insertion hole 12a, the hub head 13a of the hub bolt 13 is contacted from the axial direction, and the inclination of the hub bolt 13 is suppressed. The bolt receiving surface 121a is formed by spot facing after forging the wheel mounting flange 12.

  The stepped surface 122a has a shape having a substantially regular hexagonal outer contour along the parallel direction of the plurality of bolt detent surfaces 120a and a substantially circular inner contour along the circumferential direction of the bolt receiving surface 121a. The bolt rotation stop surface 120a and the bolt receiving surface 121a are interposed between the bolt insertion hole 12a and the bolt press-fitting side opening at the center in the axial direction.

  On the other hand, as shown in FIGS. 3A and 3B, the hub bolt 13 has a bolt head portion 13a, a bolt press-fit portion 13b, and a bolt screw portion 13c. The hub bolt 13 is press-fitted into the bolt insertion hole 12 a and attached to the wheel mounting flange 12.

  The bolt head 13a includes a bolt engaging surface 130a that engages the bolt detent surface 120a in the circumferential direction, a bolt contact surface 131a that contacts the bolt receiving surface 121a in the axial direction, and a stepped surface 122a of the bolt insertion hole 12a. And a stepped head having a substantially regular hexagonal shape having a wheel-side end face 132a facing each other at a predetermined interval, and is disposed on the vehicle body side of the hub bolt 12.

  The bolt contact surface 131a is formed as an axial end surface of a portion protruding to the press-fitting direction side (the bolt screw portion 13c side) from the axial end portion of the bolt engaging surface 130a. The bolt contact surface 131a is formed on an annular flat surface that is in surface contact with the bolt receiving surface 121a.

  The wheel-side end surface 132a is an axial end surface of the portion where the bolt engaging surface 130a is formed on the outer peripheral surface, and the hub bolt 13 is press-fitted into the bolt insertion hole 12a and the bolt detent surface 120a also receives the bolt. It is configured as a non-contact surface that does not contact the surface 121a.

  The bolt press-fit portion 13b is disposed between the bolt head portion 13a and the bolt screw portion 13c. A serration 130b corresponding to the serration 123a of the bolt insertion hole 12a is formed in the bolt press-fitting portion 13b.

  The bolt screw portion 13 c is disposed on the wheel side of the hub bolt 13. The bolt screw portion 13c is configured to screw a hub nut (not shown) and attach the wheel to the wheel attachment flange 12 together with the brake rotor.

(Mounting of hub bolt 13 to wheel mounting flange 12)
The hub bolt 13 is attached to the wheel mounting flange 12 by engaging the bolt engaging surface 130a of the bolt head 13a with the bolt detent surface 120a of the bolt insertion hole 12a, and the bolt contact surface 131a of the bolt head 13a. Until the bolt is in contact with the bolt receiving surface 121a of the bolt insertion hole 12a, the bolt press-fitting portion 13b of the hub bolt 13 is pressed into the bolt insertion hole 12a of the wheel mounting flange 12 and inserted therethrough.

  By press-fitting the hub bolt 13 into the bolt insertion hole 12a, the serration 130b of the bolt press-fitting portion 13b and the serration 123a of the bolt insertion hole 12a are engaged with each other, and the hub bolt 13 is attached to the wheel mounting flange 12.

[Effect of the embodiment]
According to the embodiment described above, the following effects can be obtained.

(1) Compared to the case where the hub bolt 13 is press-fitted with a press-fit tightening allowance that can prevent the hub bolt 13 from being rotated only by the bolt press-fitting portion 13b, the press-fit tightening allowance can be reduced. The deformation can be suppressed, and the surface runout accuracy of the wheel mounting flange 12 can be increased.

(2) Since the wheel side end surface 132a of the bolt head 13a faces the stepped surface 122a of the bolt insertion hole 12a with a predetermined interval, that is, the stepped surface 122a of the bolt insertion hole 12a and the wheel of the bolt head 13a. Since an annular gap is formed between the side end surface 132a, there is a machining error at the axial end of the bolt detent surface 120a (the boundary between the bolt detent surface 120a and the stepped surface 122a). However, the bolt abutment surface 131a abuts on the bolt receiving surface 121a without being affected by this, and the inclination of the hub bolt 13 can be suppressed.

  As described above, the bolt mounting mechanism and the wheel bearing device of the present invention have been described based on the above-described embodiment, but the present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the scope of the present invention. For example, the following modifications are possible.

(1) In the above embodiment, the case where the bolt head 13a of the hub bolt 13 is a stepped head having a substantially regular hexagonal shape has been described. However, the present invention is not limited to this, and the bolt head is, for example, a flat surface. It may be a planar polygonal shape such as a substantially quadrangular shape or a substantially planar octagonal shape. That is, at least a part of the outer peripheral surface of the bolt head 13a of the hub bolt 13 is formed into a flat surface or a curved surface inclined with respect to the circumferential direction of the central axis of the hub bolt 13, and the bolt detent surface 120a is formed of the bolt head 13a. It is only necessary to have a shape capable of preventing rotation corresponding to the shape of the outer peripheral surface of the.

  Moreover, the hub bolt 20 which has the bolt head 20a as shown in FIG. 4 may be sufficient. In FIG. 4, the bolt head 20a of the hub bolt 20 is integrally provided with convex portions 200a arranged in parallel in the circumferential direction at a predetermined interval, and the outer surface of the convex portion 200a corresponds to a bolt detent surface. In this case, in the bolt insertion hole, a concave portion is provided as a bolt anti-rotation portion that corresponds to the convex portion 200a and prevents the hub bolt 20 from rotating.

(2) In the above embodiment, the case where the bolt insertion hole 12a is formed by the concave portion having the stepped surface 122a has been described. However, the present invention is not limited to this, and a step as shown in FIG. You may form by the bolt penetration hole 12a which does not have the shape surface 122a. In this case, the wheel side end surface 132a of the hub bolt 13 faces the bolt receiving surface 121a of the bolt insertion hole 12a with a predetermined interval.

(3) In the above embodiment, the case where the bolt head 13a of the hub bolt 13 is formed to have a stepped shape between the bolt contact surface 131a and the wheel side end surface 132a has been described. However, as shown in FIG. 5B, the tapered surface 133a has a conical diameter increasing from the end in the radial direction of the bolt contact surface 131a toward the bolt engaging surface 130a. It may be formed. In this case, the taper surface 133a is a non-contact surface that does not contact the bolt detent surface 120a or the bolt receiving surface 121a.

(4) In the above-described embodiment, the case where the rolling elements 6 and 7 are both steel balls has been described. However, the present invention is not limited to this, and may be a rolling element including, for example, a cylindrical roller or a conical roller. .

(5) In the above embodiment, the case of application to the flange-integrated hub shaft 8 has been described. However, the present invention is not limited to this. For example, the present invention is also applied to a wheel mounting flange or a drive shaft-integrated hub. It is applicable in the same manner as in

DESCRIPTION OF SYMBOLS 1 ... Wheel bearing apparatus, 2 ... Bearing, 3 ... Bolt attachment mechanism, 4 ... Inner member, 5 ... Outer member, 5a, 5b ... Outer rolling surface, 5c ... Body mounting flange, 50c ... Bolt insertion hole 6, 7 ... rolling elements, 8 ... hub axle, 8a ... large diameter barrel, 8b ... small diameter barrel, 8c ... through hole, 80a ... inner rolling surface, 80c ... serration, 9 ... inner ring, 9a ... Inner rolling surface, 10, 11 ... seal member, 12 ... wheel mounting flange, 12a ... bolt insertion hole, 120a ... bolt detent surface, 121a ... bolt receiving surface, 122a ... stepped surface, 123a ... serration, 13 ... Hub bolt, 13a ... bolt head, 130a ... bolt engagement surface, 131a ... bolt contact surface, 132a ... wheel side end face, 13b ... bolt press-fit portion, 130b ... serration, 13c ... bolt screw portion, O ... center axis, O ₁ ... axis

Claims (2)

A bolt head and a bolt screw portion, a bolt press-fit portion interposed between the bolt head portion and the bolt screw portion, and a wheel mounting bolt for mounting a wheel;
A hub shaft on which a wheel mounting flange having a bolt insertion hole for inserting and inserting the bolt press-fitting portion of the wheel mounting bolt is formed;
A bearing that rotatably supports the hub shaft;
The bolt insertion hole of the wheel mounting flange has a bolt detent surface that prevents the wheel mounting bolt from rotating, and a bolt receiving surface that receives the bolt head of the wheel mounting bolt in the axial direction,
The bolt head of the wheel mounting bolt includes a bolt engaging surface that engages with the bolt detent surface, a bolt abutting surface that abuts on the bolt receiving surface, and the bolt engaging surface and the bolt abutting surface. And a non-contact surface that does not contact the bolt detent surface and the bolt receiving surface in a state of being press-fitted into the bolt insertion hole. The wheel mounting flange is stepped bolt press-side opening of the bolt insertion hole is interposed between the bolt receiving surface and the bolt detent surface, and facing the non-contact surface of the bolt head The wheel bearing device according to claim 1, comprising a surface.

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