JP2009067339A - Bearing unit - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a bearing unit having a hub bolt mounting structure hardly causing looseness of a hub bolt, and hardly causing rupture of the hub bolt even when an unexpected impact load is input to a disk wheel. <P>SOLUTION: This bearing unit includes: a stationary ring (outer ring) 2 fixed to the side of a vehicle body; a rotational ring (inner ring) 4 to which components on the side of a wheel (a brake rotor BR and a disk wheel (aluminum wheel) DW) arranged oppositely to the outer ring and arranged on the side of the wheel are fixed, and rotated together with the wheel; and rolling elements 6, 7. The bearing unit has a structure provided with a disk-shaped hub flange 12a extending outward from the side of the vehicle body of the inner ring and positioning the components on the side of the wheel, and a hub bolt hole 12a arranged at a predetermined interval along the peripheral direction of the hub flange, so that the hub bolt 14 is pressure-fitted into the hub bolt hole toward the side of the wheel. An elastic body (spring washer) 15 is interposed between the surface S1 of the hub flange on the side of the vehicle body and the head part 14b of the hub bolt. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a bearing unit that supports a wheel, and more particularly to a hub bolt mounting structure.

2. Description of the Related Art Conventionally, various bearing units for supporting a vehicle wheel (for example, a disc wheel DW) rotatably with respect to a vehicle body (for example, a suspension device) are known.
For example, the bearing unit shown in FIG. 4 is provided with a stationary wheel (for example, an outer ring) 2 fixed to the vehicle body side via a fixing flange 2a, and is provided facing the inner side of the outer ring 2 and connected (fixed) to the wheel side. And a substantially cylindrical hub 12 that rotates while supporting a wheel side component (for example, a disc wheel DW or a brake rotor BR of an automobile), and an inner ring structure 13 that is fitted to the outer peripheral body of the hub 12 on the vehicle body side. And a plurality of rolling elements 6 and 7 rotatably incorporated in a double row (for example, two rows) between the outer ring 2 and the inner ring 4.

A disc-shaped hub flange 12a extending from the outer peripheral wheel side of the hub 12 to the outside (radially outward of the hub 12) beyond the outer ring 2 is protruded and is near the extended edge. Are provided with a plurality of hub bolt holes 12b arranged at predetermined intervals along the circumferential direction.
In the hub flange 12a shown in FIG. 4, the plurality of hub bolt holes 12b have female threads on their inner diameter surfaces. When the hub bolt 14 is screwed into the hub bolt hole 12b, the wheel side component (disc wheel DW or brake rotor BR) is fixed to the wheel side surface S2 of the hub flange 12a.

  In this case, as in the case of the disc wheel DW shown in FIG. 4, if the steel wheel is manufactured by processing an iron plate, the bolt hole DWH of the iron rim is usually formed so as to protrude in the axial direction away from the hub flange 12a. (See Patent Document 1). For this reason, when the hub bolt 14 is inserted into the bolt hole DWH and screwed into the hub bolt hole 12b, the bolt hole DWH is pressed in the direction of the hub flange 12a and the elasticity in the axial direction separated from the hub flange 12a by the iron rim is increased. work. This elasticity contributes to preventing the hub bolt 14 from breaking when the hub bolt 14 is loosened or when an unexpected impact load is input to the disc wheel DW.

  In recent years, aluminum wheels made of aluminum material have become widespread for the purpose of aesthetic beauty and weight reduction. FIG. 5 shows a case where such a disc wheel DW (aluminum wheel) is attached to a bearing unit. Show. In FIG. 5, hub bolts 14 are press-fitted into the plurality of hub bolt holes 12 b of the hub flange 12 a toward the wheel side, and by tightening the hub nut 14 a into the hub bolt 14, the wheel side component (disc wheel DW or The brake rotor BR) is fixed.

In this case, the bolt hole DWH of the disc wheel DW (aluminum wheel) is seated in a bowl shape in accordance with the inclined surface of the hub nut 14a, and the bolt hole DWH and the hub nut 14a are formed so as to come into contact with the taper. When the bolt hole DWH is inserted into the hub bolt 14 and the hub nut 14a is tightened, the disc wheel DW is pressed and fixed without any gap in the direction of the hub flange 12a without any elasticity.
For this reason, the hub bolt 14 is relatively loose, and when an unexpected impact load is input to the disc wheel DW, the hub bolt 14 tends to break and becomes a problem.

  In this case, if a spring washer or the like is interposed between the bolt hole DWH and the hub nut 14a, the above-mentioned problem can be solved by acting in the axial direction away from the hub flange 12a. Since the bolt hole DWH and the hub nut 14a are formed so as to come into contact with the taper, it is difficult to interpose a spring washer or the like.

JP 2006-112605 A

  An object of the present invention is to provide a bearing unit having a hub bolt mounting structure in which a hub bolt is not easily loosened and the hub bolt is not easily broken even when an unexpected impact load is input to a disc wheel.

  In order to achieve the above object, a bearing unit according to the present invention includes a stationary wheel fixed to the vehicle body side and a wheel-side component provided facing the stationary wheel and disposed on the wheel side together with the wheel. A rotating wheel that rotates, and a plurality of rolling elements that are rotatably incorporated between raceway surfaces formed on opposite surfaces of the rotating wheel and the stationary wheel, respectively, and outward from the vehicle body side of the rotating wheel. And a disc-shaped hub flange for positioning the wheel side component, and a plurality of hub bolt holes provided near the extension edge of the hub flange and arranged at predetermined intervals along the circumferential direction. A bearing unit having a configuration in which a hub bolt is press-fitted into the hub bolt hole toward the wheel side, and an elastic body is interposed between a body surface of the hub flange and a head portion of the hub bolt, and Is that . The wheel side component may be a light alloy disc wheel.

  According to the present invention, it is possible to provide a bearing unit having a hub bolt mounting structure in which the hub bolt is not easily loosened and the hub bolt is not easily broken even when an unexpected impact load is input to the disc wheel.

Hereinafter, a bearing unit according to an embodiment of the present invention will be described with reference to the accompanying drawings.
As shown in FIG. 1A, the bearing unit of the present embodiment is provided facing the outer ring 2 as a stationary ring that is fixed to the vehicle body side and is always kept in a non-rotating state, and the inner side of the outer ring 2. Further, the inner ring 4 as a rotating wheel connected (fixed) to the wheel side and rotating together with the wheel, and a plurality of rolling elements 6 rotatably incorporated between the outer ring 2 and the inner ring 4 in a double row (for example, two rows). , 7.

The outer ring 2 has a hollow cylindrical shape and is disposed so as to cover the outer periphery of the inner ring 4. Between the outer ring 2 and the inner ring 4, there is a seal member (on the vehicle body side) for sealing the inside of the bearing unit. A pack seal 10a and a wheel side lip seal 10b) are provided. In addition, although the ball | bowl is illustrated in drawing as the rolling elements 6 and 7, a roller may be applied according to the structure and kind of bearing unit.
The outer ring 2 is provided with a hub fixing flange 2a that protrudes outward from the outer peripheral surface of the outer ring 2 and is integrally formed. A fixing bolt (not shown) is inserted into the fixing hole 2b of the fixing flange 2a. By fastening to the side housing, the outer ring 2 can be fixed to a suspension device (not shown).

The inner ring 4 includes a substantially cylindrical hub 12 that rotates while supporting wheel-side components (for example, a disc wheel DW and a brake rotor BR of an automobile), and an inner ring component 13 that is fitted to the outer peripheral surface of the hub 12 on the vehicle body side. It consists of and.
A disc-shaped hub flange 12a to which a wheel-side component (disc wheel DW or brake rotor BR) is fixed protrudes from the outer peripheral surface wheel side of the hub 12. The hub flange 12a extends in a disk shape from a position spaced a predetermined distance in the wheel direction from the raceway surface 12e with which the rolling element 7 on the wheel side of the hub 12 contacts, outward (radially outward of the hub 12). In the vicinity of the extended edge, a plurality of hub bolt holes 12b arranged at predetermined intervals along the circumferential direction are provided, and hub bolts 14 are press-fitted toward the wheel side in the plurality of hub bolt holes 12b. .

In this case, the brake rotor BR is inserted by positioning by inserting a plurality of hub bolts 14 into a plurality of bolt holes formed in the brake rotor BR, and the disc wheel DW also forms a plurality of hub bolts 14 on the disc wheel DW. The disc wheel DW and the brake rotor BR are fastened together with the hub flange 12a by being inserted into the plurality of bolt holes and tightened with the hub nut 14a, and the wheel side surface of the hub flange 12a is connected to the disc wheel DW and the brake rotor BR. While being able to follow along with S2 without a gap, it can position and fix to hub flange 12a.
The disc wheel DW is made of a light alloy (for example, aluminum or magnesium) material, and the bolt hole DWH of the disc wheel DW is seated in a bowl shape in accordance with the inclined surface of the hub nut 14a. The bolt hole DWH and the hub nut 14a Are formed so as to be per taper.

Further, as a characteristic configuration of the present invention, an elastic body is interposed between the vehicle body side surface S1 of the hub flange 12a and the head 14b of the hub bolt 14 of the present embodiment. In the present embodiment, a spring washer 15 is employed as an example of the elastic body.
As shown in FIG. 1 (b), the spring washer 15 is formed in a C shape with a part of an annular ring intermittently, and a pair of intermittent ends 15a and 15b are spaced apart from each other in opposite axial directions. And has elasticity that expands in the axial direction.

As a result, the head 14b of the hub bolt 14 is subjected to an elastic force in a direction away from the vehicle body-side surface S1 of the hub flange 12a of the present embodiment, so the disk wheel DW (wheel side component) is tightened by tightening the hub nut 14a. ) Is fixed between the surface S1 of the hub flange 12a on the vehicle body side and the head 14b of the hub bolt 14 according to the amount of expansion of the spring washer 15.
The elastic force acts on the meshing portion of the hub bolt 14 and the hub nut 14a, so that the hub nut 14a is not easily loosened, and a gap is formed between the head 14b of the hub bolt 14 and the disk wheel DW. The gap absorbs the amount of elongation of the hub bolt 14 when an unexpected impact load is input, so that excessive stress is not applied to the hub bolt 14 and it is difficult to break.

When a light metal disc wheel DW (for example, an aluminum wheel) is fixed to a steel hub flange 12a, there is a difference in potential between the two, so that electric corrosion may occur. In some cases, the disc wheel DW may become thin and the axial dimension may decrease, or metal oxide (for example, aluminum oxide) may be clogged between the disc wheel DW and the hub flange 12a and the axial dimension may increase.
Even in this case, the increase / decrease in the axial dimension is absorbed by the gap between the vehicle body-side surface S1 of the hub flange 12a and the head 14b of the hub bolt 14, and the hub bolt 14 can be prevented from loosening or tensioning. .

  In the present embodiment, the case where the spring washer 15 is employed as an example of the elastic body interposed between the vehicle body side surface S1 of the hub flange 12a and the head 14b of the hub bolt 14 has been described. Another elastic body may be employed as long as it has an elastic force in the axial direction and is interposed between the surface S1 on the vehicle body side and the head 14b of the hub bolt 14. For example, as a modification of the present embodiment, the wave washer 16 may be employed as the elastic body.

As shown in FIG. 2B, the wave washer 16 is formed by bending portions 16a and 16a of the annular ring toward one side in the axial direction, and other portions 16b and 16b of the annular ring in the axial direction. It is formed by being bent to the other side, has an S-shape in a side view (see FIG. 2A), and has elasticity that expands in the axial direction. As a result, the head 14b of the hub bolt 14 is subjected to an elastic force in a direction away from the vehicle body-side surface S1 of the hub flange 12a of the present embodiment, so the disk wheel DW (wheel side component) is tightened by tightening the hub nut 14a. ) Is fixed, a gap corresponding to the bending amount of the wave washer 16 is provided between the vehicle body side surface S1 of the hub flange 12a and the head 14b of the hub bolt 14.
Even when such a wave washer 16 is employed as the elastic body, the same effect as that of the above-described embodiment can be obtained by the elastic force of the wave washer 16.
In this modification, the wave washer 16 having two portions 16a and 16a and two other portions 16b and 16b of the ring is adopted. However, the number of portions and other portions of the ring is as follows. It is not limited to, You may have more than two places.

As another modification of the present embodiment, a dish washer 17 may be adopted as the elastic body. As shown in FIG. 3B, the dish washer 17 is formed such that the inner diameter side 17b of the washer protrudes in the axial direction from the outer diameter side 17a, and has elasticity that expands in the axial direction.
As a result, the head 14b of the hub bolt 14 is subjected to an elastic force in a direction away from the vehicle body-side surface S1 of the hub flange 12a of the present embodiment, so the disk wheel DW (wheel side component) is tightened by tightening the hub nut 14a. ) Is fixed, there is a gap corresponding to the amount of protrusion of the dish washer 17 between the vehicle body side surface S1 of the hub flange 12a and the head 14b of the hub bolt 14.
Even when such a dish washer 17 is employed as an elastic body, the same effects as those of the above-described embodiment can be obtained by the elastic force of the dish washer 17.

It is explanatory drawing of the bearing unit which uses the spring washer as an elastic body by this invention, (a) is a schematic sectional drawing of a bearing unit, (b) is a perspective view explaining the characteristic of a spring washer. It is explanatory drawing of the bearing unit which uses a wave washer as an elastic body by this invention, (a) is a schematic sectional drawing of a bearing unit, (b) is a perspective view explaining the characteristic of a wave washer. It is explanatory drawing of the bearing unit which uses the plate washer as an elastic body by this invention, (a) is a schematic sectional drawing of a bearing unit, (b) is a perspective view explaining the characteristic of a plate washer. It is a schematic sectional drawing of the conventional bearing unit which fixed the iron disc wheels. It is a schematic sectional drawing of the conventional bearing unit which fixed the disc wheel made from light metal.

Explanation of symbols

2 Outer ring 4 Inner ring 6, 7 Rolling element 12 Hub 12a Hub flange 12b Hub bolt hole 14 Hub bolt 14a Hub nut 14b Hub bolt head DW Disc wheel BR Brake rotor S1 Hub flange side surface

Claims (2)

A stationary wheel fixed to the vehicle body side,
A rotating wheel that is provided facing the stationary wheel and that is disposed on the wheel side and that rotates together with the wheel.
Including a plurality of rolling elements that are rotatably incorporated between raceway surfaces formed on opposing surfaces of the rotating wheel and the stationary wheel,
A disc-shaped hub flange that extends outward from the vehicle body side of the rotating wheel and positions the wheel-side components;
A plurality of hub bolt holes provided near the extension edge of the hub flange and arranged at predetermined intervals along the circumferential direction;
In the bearing unit having a configuration in which the hub bolt is press-fitted into the hub bolt hole toward the wheel side,
A bearing unit characterized in that an elastic body is interposed between a surface of the hub flange on the vehicle body side and a head of the hub bolt. The bearing unit according to claim 1, wherein the wheel-side component is a light alloy disk wheel.

Images