JP2008121774A - Rolling bearing device for wheels - Google Patents

Abstract

The present invention provides a wheel rolling bearing device capable of preventing a disk rotor from being deformed due to thermal expansion.
SOLUTION: Double row rolling elements 3 and 4 are movably interposed between the two so that an outer cylinder member 2 rotates relative to an inner shaft member 1. A disc rotor 5 for braking is attached to the outer cylinder member 2. The outer cylinder member 2 is formed with a mounting surface 7 for mounting along the inner circumferential side surface of the disk rotor 5. A bolt 8 protruding from the mounting surface 7 and passing through an insertion hole 11 formed in the disk rotor 5, a nut 9 screwed into the bolt 8 and sandwiching the disk rotor 5 between the mounting surface 7, and a nut 9 And a disc spring 10 interposed between the disc rotor 5 and the disc rotor 5. The disc spring 10 absorbs deformation of the disc rotor 5 in the bolt axis direction.
[Selection] Figure 1

Description

  The present invention relates to a wheel rolling bearing device in which an outer cylinder member rotates with respect to an inner shaft member.

  Conventionally, what is known as a rolling bearing device (hub unit) for a wheel in an automobile includes an inner shaft member fixed to a suspension on the vehicle body side, and a wheel provided radially outward of the inner shaft member. There are provided an outer cylinder member to be attached and a double row rolling element interposed between the inner shaft member and the outer cylinder member so as to be freely rotatable, and the outer cylinder member rotates with respect to the inner shaft member. (For example, refer to Patent Document 1).

  In addition to the wheels, a disk rotor (brake disk) for a disk brake is attached to the outer cylinder member. In the rolling bearing device described in Patent Document 1, an annular flange portion is formed on the outer cylinder member, and a wheel and a disk rotor of a wheel are attached to the flange portion. Specifically, it is a structure in which a wheel is attached to one surface side of the flange portion and a disk rotor is attached to the other surface side by bolts inserted through the flange portion.

Japanese Patent Publication No.49-19361 (see FIG. 8)

  In the wheel rolling bearing device described in Patent Document 1, the wheel of the wheel is fixed between the nut and one surface of the flange portion by tightening the nut to the bolt on the one surface side of the flange portion. . Further, on the other surface side of the flange portion, the inner peripheral portion of the disk rotor is fixed in close contact with each other between the plate-shaped head portion of the bolt and the other surface of the flange portion. That is, the disc rotor is fixed to the flange portion in a state of being restrained in the axial direction.

  When such a wheel rolling bearing device is mounted on a vehicle and used, the disk rotor generates heat and expands due to frictional heat between the disk rotor and the brake pad during braking. In this case, in the rolling bearing device described in Patent Document 1, the portion near the outer periphery of the disk rotor can be thermally expanded, but the portion near the inner periphery of the disk rotor is fixed in a state of being restrained by the flange portion. Thermal expansion is suppressed at the inner peripheral portion. As a result, the disk rotor is deformed, and the sliding surface thereof is inclined with respect to a plane orthogonal to the axis of the outer cylinder member, so that there is a possibility that the braking performance is deteriorated or abnormal noise or vibration occurs.

  Accordingly, the present invention has been made in view of the above-described problems, and an object thereof is to provide a wheel rolling bearing device that can alleviate deformation due to thermal expansion of a disk rotor.

  In order to achieve the above object, a rolling bearing device for a wheel according to the present invention includes an inner shaft member fixed to a vehicle body side, an outer cylinder member provided on a radially outer side of the inner shaft member, to which a wheel is attached, A brake disk rotor attached to the outer cylinder member, and a double row rolling element interposed between the inner shaft member and the outer cylinder member so as to be freely rollable; In the wheel rolling bearing device that rotates with respect to the inner shaft member, a mounting surface that is formed on the outer cylinder member and is mounted along a side surface near the inner periphery of the disk rotor, and that protrudes from the mounting surface and is formed on the disk rotor. A bolt that is inserted through the insertion hole, a nut that is screwed into the bolt and sandwiches the disk rotor between the mounting surface, and a portion provided between the nut and the mounting surface. Those having an elastic member that absorbs the thermal deformation of the bolt axial direction of the rotor.

  According to this configuration, since the disk rotor is mounted with the elastic member interposed between the nut and the mounting surface, if the disk rotor is thermally expanded and deformed in the bolt axis direction, This deformation can be absorbed by the elastic deformation of the member. Therefore, according to this elastic member, it is possible to prevent the disk rotor from being restrained, and to reduce deformation due to thermal expansion of the disk rotor.

In the rolling bearing device for a wheel, a plurality of the insertion holes are formed in the disk rotor in a circumferential direction, and the insertion holes are fitted in the circumferential direction with the bolts and are in a direction perpendicular to the bolts. It is preferable that it is a long hole which produces a clearance gap between said bolts.
When the disk rotor is thermally expanded, the insertion hole is displaced radially outward. However, since the insertion hole is a long hole that creates a gap with the bolt in the direction along the radial direction of the disk rotor, even if the insertion hole is displaced in the radial direction, the deformation can be absorbed by the gap. The disk rotor is not restrained by the bolt portion. And since this elongate hole is fitting with the volt | bolt about the direction along the circumferential direction of a disk rotor, torque transmission with a disk rotor and an outer cylinder member is performed reliably.

  In the wheel rolling bearing device, the elastic member is preferably a disc spring. According to this, the elastic member has a simple structure, and the elastic member can be easily attached. When the disc rotor is thermally expanded and deformed in the bolt axis direction, the disc spring can be elastically deformed to absorb this deformation.

  According to the rolling bearing device for a wheel of the present invention, when the disk rotor is thermally expanded and deformed in the bolt axis direction, the elastic member is elastically deformed to absorb this deformation. Therefore, according to this elastic member, it is possible to prevent the disk rotor from being restrained, and to reduce deformation due to thermal expansion of the disk rotor.

Embodiments of the present invention will be described below with reference to the drawings.
FIG. 1 is a cross-sectional view showing an embodiment of a rolling bearing device for a wheel according to the present invention. This wheel rolling bearing device (hereinafter also simply referred to as a rolling bearing device) includes an inner shaft member 1 fixed to the vehicle body side, and a wheel (not shown) provided radially outward of the inner shaft member 1. An outer cylinder member 2 to be attached, and double row rolling elements 3 and 4 interposed between the inner shaft member 1 and the outer cylinder member 2 so as to roll freely are provided.

Double-row track surfaces 13 and 14 are formed on the outer peripheral surface of the inner shaft member 1. The inner shaft member 1 includes an inner shaft 15 and an inner ring member 16 that is externally fitted to one end portion of the inner shaft 15. The inner ring member 16 is secured by a nut 17 that is screwed into an end portion of the inner shaft 15. It is fixed. One of the raceway surfaces 13 is formed on a part of the outer peripheral surface of the inner shaft 15, and the other raceway surface 14 is formed on the outer peripheral surface of the inner ring member 16.
Further, the inner ring member 16 side (right side in FIG. 1) is the outer side of the rolling bearing device, and the end side (left side in FIG. 1) of the inner shaft 15 opposite to the axial direction is the inner side. A flange portion 18 is formed on the inner side of the inner shaft 15. In this flange portion 18, the rolling bearing device is fixed to a suspension device (not shown) on the vehicle body side.

The outer cylinder member 2 has a cylindrical shape, and double-row track surfaces 23 and 24 are formed on the inner peripheral surface thereof. Then, between the double-row raceway surfaces 23 and 24 of the outer cylinder member 2 and the double-row raceway surfaces 13 and 14 of the inner shaft member 1, the balls 3 and 4 as rolling elements can roll freely. Intervene. Thereby, the outer cylinder member 2 and the inner shaft member 1 are disposed concentrically, and the outer cylinder member 2 can rotate about the axis C0 with respect to the inner shaft member 1.
A seal member 30 is interposed on the inner side between the inner shaft member 1 and the outer cylinder member 2. A circular lid member 31 is attached to the outer side of the outer cylinder member 2 to conceal the bearing portion including the rolling element and its raceway surface. The seal member 30 and the lid member 31 prevent foreign matter from entering the bearing portion.

This rolling bearing device further includes a disk rotor (brake disk) 5 for a disk brake. The disk rotor 5 is attached to the outer cylinder member 2.
The outer cylinder member 2 is formed with a first attachment portion 21 for attaching a wheel (tire) and a second attachment portion 22 for attaching the disc rotor 5. The first attachment portion 21 and the second attachment portion 22 are formed at different positions in the axial direction. The first attachment portion 21 is a flange portion 25 in which an end surface of the outer cylinder member 2 on the axial direction outer side is an attachment surface 25a. The second attachment portion 22 is a stepped portion 26 on the axial inner side of the outer cylinder member 2.
A bolt (hub bolt) 27 is attached to the flange portion 25 which is the first attachment portion 21, and a wheel (not shown) is attached by the bolt 27.

FIG. 2 is an enlarged cross-sectional view illustrating the stepped portion 26 that is the second mounting portion 22. The stepped portion 26 formed on the outer peripheral side portion of the outer cylinder member 2 includes a cylindrical portion 28 formed as a circular outer peripheral surface centering on the axis C0 (see FIG. 1), and an annular surface orthogonal thereto. And an attachment surface 7 formed as follows. The attachment surface 7 is formed on the outer cylinder member 2 so as to be attached along the side surface near the inner periphery that is the outer side surface of the disk rotor 5.
A bolt 8 is attached to the outer peripheral side portion of the outer cylinder member 2 in a state of being inserted from the outer side toward the inner side. The front end of the bolt 8 protrudes from the mounting surface 7, and the bolt 8 is inserted through an insertion hole 11 formed in the disk rotor 5. Further, a nut 9 screwed to the tip end portion of the bolt 8 is provided, and the nut 9 is fixed with the disc rotor 5 sandwiched between the mounting surface 7.
In the second mounting portion 22, the elastic member 10 is provided in a portion between the nut 9 and the mounting surface 7. The elastic member 10 can absorb the deformation of the disk rotor 5 in the direction of the bolt axis C1 by making the disk rotor 5 movable in the direction of the bolt axis C1.

  The elastic member 10 is interposed between the inner peripheral side surface 5b on one surface side (inner side surface) of the disk rotor 5 and the nut 9, and the other surface of the disk rotor 5 (outer side surface) The mounting surface 7 is in surface contact. The disc rotor 5 is attached in a state of being fitted on the cylindrical portion 28.

  The elastic member 10 is a plurality of disc springs, and in FIG. 2, it is two disc springs. The disc spring 10 is elastically compressed and deformed in a state in which the nut 9 is fastened to the bolt 8. The disc spring 10 is subjected to a force of pushing the disc rotor 5 with an elastic restoring force, and is also elastically deformed. It is also possible. Thereby, the disk rotor 5 can be firmly attached to the outer cylinder member 2 by the bolt 8, the nut 9, and the disc spring 10, and when the disk rotor 5 is thermally expanded and deformed in the direction of the bolt axis C1, The disc rotor 5 can be deformed in the direction of the bolt axis C1 by the elastic deformation of the disc spring 10.

  In the outer cylinder member 2, a hole 29 is formed through the mounting surface 25a of the wheel mounting flange 25 (see FIG. 1) in a direction parallel to the axis C0, and the bolt 8 is inserted into the hole 29. ing. In FIG. 2, the head 8c of the bolt 8 is housed in a counterbore hole 29a at the end of the hole 29, and the head 8c of the bolt 8 does not protrude from the mounting surface 25a. Thereby, the attachment of the wheel on the attachment surface 25a is not obstructed by the head 8c of the bolt 8. And the serration part 8a is formed in the base end part side (neck part) of the axial part of the volt | bolt 8, The part of the hole 29 is made into the shape corresponding to this, The rotation prevention of the volt | bolt 8 is prevented. .

In addition, for the wheel mounting bolt 27 (see FIG. 1), the axial direction from the head toward the tip where the nut (not shown) is screwed is the direction from the inner side to the outer side. On the other hand, the bolt 8 for attaching the disk rotor 5 is the opposite, and the axial direction from the head toward the tip where the nut 9 is screwed is the direction from the outer side toward the inner side.
Further, the inner diameter dimension of the hole 29 of the outer cylinder member 2 and the outer diameter dimension of the portion of the bolt 8 that is inserted into the hole 29 are substantially the same. As a result, in a state where the rolling bearing device is attached to a vehicle and used, a braking torque that acts on the disc rotor 5 during braking is transmitted to the outer cylinder member 2 via the bolt 8, and the strength of the bolt 8 is increased. Can be high.

The disk rotor 5 is fixed to the outer cylinder member 2 at a plurality of locations in the circumferential direction by a plurality of sets of bolts 8, nuts 9, and disc springs 10. In other words, mounting insertion holes 11 through which the bolts 8 are inserted are formed at a plurality of locations in the circumferential direction of the disk rotor 5. FIG. 3 is a view showing a cross section of the insertion hole 11 formed in the disk rotor 5 and the bolt 8 passing through the insertion hole 11.
The insertion hole 11 for the bolt 8 is fitted with the bolt 8 in a direction along the circumferential direction of the disk rotor 5, and a gap g is formed between the bolt 8 in a radial direction that is a direction perpendicular to the bolt 8. It is a long hole that causes Specifically, in this long hole 11, the dimension r2 in the direction along the radial direction (arrow b) of the disk rotor 5 is larger than the dimension r1 in the direction along the circumferential direction (arrow a) of the disk rotor 5. A long hole 11 is formed (r2> r1).

  The long hole 11 will be further described. The outer diameter dimension of the middle portion 8b of the bolt 8 through which the long hole 11 is inserted and the short axis dimension r1 of the long hole 11 are substantially the same. A major axis dimension r2 which is a direction orthogonal to the minor axis direction of the long hole 11 is made larger than the outer diameter dimension of the intermediate portion 8b of the bolt 8. As a result, a gap g is formed between the long hole 11 and the bolt 8 in a direction along the radial direction of the disk rotor 5.

When such a wheel rolling bearing device is attached to a vehicle and used, frictional heat is generated by sliding contact between the disc rotor 5 and the brake pad 32 (see FIG. 1) during braking, and the disc rotor 5 Generates heat and expands.
When the disk rotor 5 is thermally expanded, the elongated hole 11 is displaced radially outward in the elongated hole 11 for bolt insertion. However, since the long hole 11 for inserting the bolt has a structure in which a gap g is generated between the bolt 8 in the radial direction of the disk rotor 5, the long hole 11 is displaced in the radial direction. Even so, the deformation can be absorbed by the gap g. Thereby, the disk rotor 5 is not restrained by the bolt 8 part. Thereby, it is possible to prevent the sliding surface 5a from being deformed due to the thermal expansion of the disk rotor 5. Further, the elongated hole 11 is structured to be fitted with the bolt 8 in the direction along the circumferential direction of the disk rotor 5, so that during braking, between the disk rotor 5 and the outer cylinder member 2, Torque transmission is performed reliably without rattling.

  Further, according to the rolling bearing device, the disc rotor 5 is attached in the second attachment portion 22 of the outer cylinder member 2 with the disc spring 10 interposed between the nut 9 and the attachment surface 7. As a result, when the disk rotor 5 is thermally expanded and deformed in the direction of the bolt axis C1, the disc spring 10 is elastically compressed and deformed to absorb this deformation. Therefore, since the disk rotor 5 is not restrained in the direction of the bolt axis C1, it is possible to prevent deformation such that the sliding surface 5a is inclined.

In the present invention, in the outer cylinder member 2, the first attachment portion 21 for attaching the wheel (tire) and the second attachment portion 22 for attaching the disc rotor 5 are formed separately. Accordingly, the axial position of the second mounting portion 22 can be freely changed regardless of the position of the first mounting portion 21. In other words, in the past, it was difficult to change the mounting position at the inner peripheral portion of the disk rotor, that is, the position of the mounting flange in the axial direction. In order to correspond, the shape of the disc brake has to be a hat shape (not shown), that is, a shape having a bent portion in the middle of the radial direction.
However, in the present invention, referring to FIG. 1, the axial position of the second mounting portion 22 can be changed in the outer cylindrical member 2, that is, the axial length of the cylindrical portion 28 of the outer cylindrical member 2. By changing the size, the axial position of the mounting surface 7 is changed, and the axial mounting position of the disk rotor 5 can be adjusted. Therefore, the disk rotor 5 can be made to correspond to the axial position of the brake pad 32 without making the disk rotor 5 into a flat disk shape, that is, a hat shape.

Further, the shape of the disk rotor 5 is not the disk shape as shown in FIG. 1, but the hat shape as described above. When this disk rotor 5 is thermally expanded, the inner circumference of the disk rotor is conventionally increased. If the offset part is fixed in a state of being restrained by the flange part and the head of the bolt, the thermal expansion suppresses deformation at the inner peripheral part, while the outer peripheral part changes (expands). Therefore, the sliding surface of the disk rotor is likely to be deformed.
However, according to the structure of the present invention, even when the disk rotor 5 is thermally expanded, the disk rotor 5 has a disk shape, and the inner peripheral portion of the disk rotor 5 is not constrained by the elastic member (between springs) 10. Therefore, it is possible to suppress the deformation that causes the sliding surface 5a of the disk rotor 5 to fall.

Further, the rolling bearing device for a wheel of the present invention is not limited to the illustrated form, and may be of other forms within the scope of the present invention, and the elastic member 10 can be elastically deformed in addition to a disc spring. The member can be made. For example, a washer made of metal or resin having elasticity can be used.
Further, in the above-described embodiment, the elastic member (disc spring) 10 has been described as being interposed between the disk rotor 5 and the nut 9, but the structure is interposed between the disk rotor 5 and the mounting surface 7. Alternatively, a structure in which the elastic member 10 is interposed between the disk rotor 5 and the nut 9 and between the disk rotor 5 and the mounting surface 7 can be employed.

It is sectional drawing which shows one Embodiment of the rolling bearing apparatus for wheels of this invention. It is an expanded sectional view explaining the 2nd attachment part for disk rotor attachment. It is a figure which shows the cross section of the volt | bolt which has penetrated the long hole formed in this disk rotor, and this long hole.

Explanation of symbols

1 Inner shaft member 2 Outer cylinder member 3 Ball (rolling element)
4 balls (rolling elements)
5 Disc rotor 5a Sliding surface 7 Mounting surface 8 Bolt 9 Nut 10 Elastic member 11 Insertion hole (long hole)
g Clearance

Claims (3)

An inner shaft member fixed to the vehicle body side, an outer cylinder member provided on a radially outer side of the inner shaft member to which a wheel is attached, a brake disk rotor attached to the outer cylinder member, and the inner shaft A rolling bearing device for a wheel in which the outer cylinder member rotates with respect to the inner shaft member, and a double row rolling element interposed between the member and the outer cylinder member so as to freely roll.
A mounting surface formed on the outer cylinder member and attached along the side surface near the inner periphery of the disk rotor, a bolt protruding from the mounting surface and passing through an insertion hole formed in the disk rotor, and a screw threaded on the bolt A nut that sandwiches the disk rotor between the mounting surface, and an elastic member that is provided in a portion between the nut and the mounting surface and absorbs thermal deformation in the bolt axis direction of the disk rotor. A rolling bearing device for a wheel, comprising:   A plurality of insertion holes are formed in the disk rotor in the circumferential direction, and the insertion holes are fitted with the bolts in the circumferential direction, and a gap is formed between the bolts in a radial direction that is perpendicular to the insertion direction. The rolling bearing device for a wheel according to claim 1, wherein the rolling bearing device is a long hole.   The wheel rolling bearing device according to claim 1, wherein the elastic member is a disc spring.

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