JP2001248671A - Bush - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a bush that is improved in durability. SOLUTION: The bush comprises an inner metal cylinder 1 having a first cylindrical portion 1a and a first flange portion 1b extending radially outward from one end of the first cylindrical portion 1a, an outer metal cylinder 2 disposed coaxially outside the inner metal cylinder 1 at an interval and having a second flagne portion 2b at the end corresponding to the first flange portion 1b, and an elastic rubber body 3 having a third flange portion 3b interposed between the first and second flange portions 1b and 2b and integrally connecting the inner and outer metal cylinders 1 and 2. The first cylindrical portion 1a of the inner metal cylinder 1 has an inversely tapering peripheral surface 1d whose diameter is gradually increased from the side of the first flange portion 1b to the other end side.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a bush that is suitably employed in a vehicle, for example, as a device for mounting a steering gear housing on a vehicle body frame by supporting the device in a vibration-proof manner and a device for connecting a suspension arm in a vibration-proof manner.

[0002]

2. Description of the Related Art Conventionally, for example, when a steering gear housing mounted on a vehicle is mounted on a vehicle body frame, a bush that supports the steering gear housing in a vibration-proof manner has been used. As such a bush, for example, those shown in FIGS. 5 to 7 are known. This bush is spaced apart from the inner cylinder 6 by a first cylinder 6a and a first flange 6b extending radially outward from one end of the first cylinder 6a. An outer cylinder fitting 7 coaxially arranged and having a second flange portion 7b at an end corresponding to the first flange portion 6b; a third cylinder portion 8a;
A rubber elastic body 8, which is provided between the inner cylindrical fitting 6 and the outer cylindrical fitting 7 and is integrally connected to each other.

As shown in FIG. 8, for example, as shown in FIG. 8, outer bushing fittings 6 and 6 are formed through mounting openings 9a provided in a steering gear housing 9 through openings on both sides.
And press-fitted, and tightened bolts (not shown) inserted into the inner holes of the inner tube fittings 5 and 5 of each bush to fix them to the vehicle body frame (not shown). used. When vibration is input between the steering gear housing 9 and the vehicle body frame during driving of the vehicle or the like, the rubber elastic body 8 is elastically deformed, so that the vibration is effectively absorbed.

In order to improve the durability of the rubber elastic body 8, such a bush is usually compressed into the cylindrical part of the rubber elastic body 8 by drawing the cylindrical part of the outer metal fitting 7. Stress is applied.

[0005]

The conventional bush has first and second flanges 6b and 7b at one end of an inner cylinder 6 and an outer cylinder 7, respectively. The third flange portion 8b of the rubber elastic body 8 is also provided between the second flange portion 7b and the second flange portion 7b.
Therefore, as described above, the steering gear housing 9
When the bushing outer metal fitting 7 is press-fitted into the through hole 9a of the inner cylinder, the inner flange 6b of the inner metal fitting 6 is separated from the second flange part 7b of the outer metal fitting 7 (Y direction in FIG. 8). The metal fitting 6 is relatively displaced. Thereby, the third flange portion 8b of the rubber elastic body 8 between the first flange portion 6b and the second flange portion 7b is connected to the first and second flange portions 6b.
b and 7b are in a state where a large tensile strain is formed. Therefore, the durability of the third flange portion 8b of the rubber elastic body 8 deteriorates, and the durability of the bush also deteriorates. It should be noted that such a state in which a large tensile strain is formed also occurs when the cylindrical portion of the outer metal fitting 7 is subjected to drawing.

The present invention has been devised in view of the above situation, and has as an object to solve the problem of providing a bush capable of improving durability.

[0007]

According to a first aspect of the present invention, there is provided an inner cylinder having a cylindrical portion and a first flange portion extending radially outward from one end of the cylindrical portion, An outer tubular fitting coaxially disposed outside the inner tubular fitting with a distance therebetween and having a second flange portion at an end corresponding to the first flange portion, the first flange portion and the second flange portion; A bush made of a rubber elastic body having a third flange portion interposed between the inner cylindrical metal member and the outer cylindrical metal member, and the cylindrical portion of the inner cylindrical metal member includes: A means having an inverted tapered outer peripheral surface whose diameter gradually increases from the first flange portion side to the other end side is employed.

[0008] According to this means, when the bushing outer metal fitting is press-fitted into the fitting hole or when the outer cylindrical metal fitting is subjected to drawing processing, the outer cylindrical metal fitting is reduced in diameter along with the outer cylindrical metal fitting. When a cylindrical portion of a rubber elastic body is compressed, a compressive force acts so that the cylindrical portion escapes to both sides in the axial direction. This compressive force is directed toward the other end of the inner cylindrical member because the outer peripheral surface of the inner cylindrical member is formed in a reverse tapered shape whose diameter gradually increases from the first flange portion side to the other end side. Acts to displace. Accordingly, since the first flange portion of the inner cylinder is displaced so as to approach the second flange of the outer cylinder, the third rubber elastic body at a portion between the first flange and the second flange is displaced. Compressive stress is applied to the flange portion, and tensile strain is not formed.

Therefore, according to the bush of the present invention,
Since the cylindrical portion of the inner cylindrical metal member has an inverted tapered outer peripheral surface whose diameter gradually increases from the first flange portion side to the other end side, the durability of the third flange portion of the rubber elastic body, and furthermore, the The durability can be improved.

[0010]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a cross-sectional view of the bush according to the present embodiment along the axial direction, and is a cross-sectional view taken along line II of FIG. 2, and FIG. FIG. 3 is a side view of the bush as seen from the direction of arrow B in FIG.

As shown in FIGS. 1 to 3, the bush of this embodiment has an inner cylindrical metal fitting 1 having a reverse tapered outer peripheral surface 1d.
And an outer cylinder fitting 2 arranged coaxially outside the inner cylinder fitting 1
And a rubber elastic body 3 interposed between the inner cylinder 1 and the outer cylinder 2.

The inner tube fitting 1 comprises a first tube portion 1a formed in a cylindrical shape, and a ring-shaped first flange portion 1b extending radially outward from one end of the first tube portion 1a. It is formed integrally with the material. Inner peripheral surface 1c of first cylindrical portion 1a
Are formed to have a substantially constant diameter. An outer peripheral surface 1d of the first cylindrical portion 1a is formed in a reverse tapered shape whose diameter gradually increases from the first flange portion 1b toward the other end. Therefore, the first cylindrical portion 1a is formed so that the thickness gradually increases from the first flange portion 1b side to the other end side.

The outer tube fitting 2 comprises a second tube portion 2a formed in a cylindrical shape, and a ring-shaped second flange portion 2b extending radially outward from one end of the second tube portion 2a. The outer tube 2 is integrally formed of a thin metal pipe having a substantially constant diameter, and the second flange portion 2b is formed by bending one end of the metal pipe outward at a substantially right angle. ing. The second cylindrical portion 2a is formed shorter than the first cylindrical portion 1a, and has an inner diameter that is larger by a predetermined dimension than the maximum outer diameter of the outer peripheral surface 1d of the first cylindrical portion 1a. The outer cylindrical member 2 is coaxially arranged at a distance outside the inner cylindrical member 1 such that the second flange portion 2b faces the first flange portion 1b at a predetermined distance.

The rubber elastic body 3 includes an inner cylindrical fitting 1 and an outer cylindrical fitting 2.
Is formed by vulcanizing a rubber material in a space between the two, and is fixed to both by vulcanization bonding.
This rubber elastic body 3 is a third cylindrical portion 3a formed in a cylindrical shape.
And a ring-shaped third flange 3b extending radially outward from one end of the third cylindrical portion 3a. The thickness of the third cylindrical portion 3a gradually decreases from the third flange portion 3b side to the other end side in correspondence with the outer peripheral surface 1d of the first cylindrical portion 1a being formed in an inversely tapered shape. ing. This third cylindrical portion 3
A pair of curls 3c, 3c each having an arc-shaped cross section are provided at a position that is axisymmetric with respect to a, and the spring constant in the direction connecting the two curls 3c, 3c is adjusted. The rubber elastic body 3 is given compressive stress to the entire rubber elastic body 3 by drawing the outer cylindrical fitting 2.

As shown in FIG. 4, for example, the bush of the present embodiment having the above-described configuration is provided with through-holes 4a provided in the steering gear housing 4 through openings on both sides thereof to form the outer cylindrical fittings 2, 2 by press fitting. At this time, the third cylindrical portion 3a of the rubber elastic body 3 inside the second cylindrical portion 2a is compressed as the diameter of the second cylindrical portion 2a of the outer cylindrical fitting 2 is reduced, so that the third cylindrical portion 2a is compressed. Part 3
A compressive force acts so that a escapes to both sides in the axial direction.

This compressive force is applied to the first cylindrical portion 1a of the inner cylindrical member 1.
Is formed in a reverse tapered shape whose diameter gradually increases from the first flange portion 1b side to the other end side, so that the inner cylindrical fitting 1 is displaced toward the other end side. I do. As a result, the first flange portion 1b of the inner cylinder 1 is displaced in the direction of the arrow X in FIG. 4 so as to approach the second flange 2b of the outer cylinder 2, so that the first flange 1b and the second flange 1b are displaced. A compressive stress is applied to the third flange portion 3b of the rubber elastic body 3 between the second elastic member 2b and the second elastic member 3, so that tensile strain is not formed.

As described above, the second cylindrical portion 2a of the outer cylindrical member 2 is subjected to the drawing process, and the third cylindrical portion 3 of the rubber elastic body 3 is drawn.
When compressive stress is applied to “a”, the same operation and effect as when press fitting the outer cylinder fittings 2, 2 into the through holes 4 a of the steering gear housing 4 are exerted. As a result, a compressive stress is applied to the third flange portion 3b of the rubber elastic body 3, so that no tensile strain is formed.

After the two bushes are attached to the through holes 4a of the steering gear housing 4 in this way, bolts (not shown) and the like inserted into the inner holes of the inner cylinder fittings 1 and 1 of each bush are provided. Tighten to body frame (not shown)
It is attached by fixing to. In this case, the axial direction of the bush is the front-rear direction of the vehicle, and the direction connecting the centers of the beams 3c, 3c of the rubber elastic body 3 and the axis is the left-right direction of the vehicle. Installed in

When vibration is input between the steering gear housing 4 and the vehicle body frame during driving of the vehicle, the rubber elastic body 3 is elastically deformed, and the vibration is effectively absorbed.

As described above, according to the bush of this embodiment, the outer peripheral surface 1d of the first cylindrical portion 1a of the inner cylindrical fitting 1
Since it is formed in an inversely tapered shape whose diameter gradually increases from the flange portion 1b side to the other end side, a compressive stress is applied to the third flange portion 3b of the rubber elastic body 3, and tensile strain is not formed. Therefore, the third rubber elastic body 3
The durability of the flange portion 3b and thus the durability of the bush can be greatly improved.

In particular, in the bush of the present embodiment, the second cylindrical portion 2a of the outer cylindrical member 2 is subjected to drawing to apply a compressive stress to the third cylindrical portion 3a of the rubber elastic body 3. Therefore, also at this time, the third flange portion 3 of the rubber elastic body 3
Since the compression stress is applied to b, the durability of the third flange portion 3b of the rubber elastic body 3 can be greatly improved.

In this embodiment, the bush for mounting the steering gear housing 4 on the vehicle body frame in a vibration-proof manner is described. However, the present invention is also applied to a bush for connecting the suspension arm in a vibration-proof manner. can do.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view along an axial direction of a bush according to an embodiment of the present invention, and is a cross-sectional view taken along line II of FIG.

FIG. 2 is a side view of the bush according to the embodiment of the present invention as viewed from the direction of arrow A in FIG.

FIG. 3 is a side view of the bush according to the embodiment of the present invention as viewed from the direction of arrow B in FIG. 1;

FIG. 4 is a cross-sectional view along an axial direction of the bush according to the embodiment of the present invention in a vehicle mounted state.

FIG. 5 is a cross-sectional view along the axial direction of a conventional bush, and is a cross-sectional view taken along line VV of FIG. 6;

FIG. 6 is a side view of a conventional bush viewed from the direction of arrow C in FIG. 5;

FIG. 7 is a side view of the conventional bush viewed from the direction of arrow D in FIG.

FIG. 8 is a cross-sectional view along the axial direction when a conventional bush is mounted on a vehicle.

[Explanation of symbols]

1, 6 ... inner cylinder fittings 1a, 6a ... first cylinder part 1b, 6b ... first flange part 1c ... inner peripheral surface
1d: Outer peripheral surface 2, 7: Outer cylinder fitting 2a: Second cylinder part 2b, 7b: Second flange part 3, 8 ... Rubber elastic body 3a, 8a: Third cylinder part 3b, 8b: Third flange part 3c ... Curving 4, 9 ... Steering gear housing 4a, 9a ... Through hole

Claims (1)

[Claims] An inner cylinder having a cylindrical portion and a first flange portion extending radially outward from one end of the cylindrical portion; and a coaxially arranged outer side of the inner cylinder with a distance therebetween. An outer cylinder fitting having a second flange portion at an end corresponding to the first flange portion, and a third flange portion interposed between the first flange portion and the second flange portion; In a bush consisting of a metal fitting and a rubber elastic body that integrally connects the outer cylindrical metal fitting, the diameter of the cylindrical part of the inner cylindrical metal fitting gradually increases from the first flange portion side to the other end side. A bush having a reverse tapered outer peripheral surface.