JPH0783259A - Bush assembly - Google Patents

Abstract

PURPOSE:To enhance stiffness in the direction of wrenching without degrading rubber's durability caused by an input in the direction of twisting by thinning the thickness of rubber interposed between an inner cylinder and and an outer cylinder in the vicinities of both the end sections of cylindrical members. CONSTITUTION:Paired bush members 3 are inserted in a cylindrical member from its open sides at both of its ends respectively, and each flange of respective outer cylinders 5 is brought into contact with each open end face of the cylifidrical member 2, so that these bushes are fastened by a bolt so as to be assembled in between paired plates 1 in a state that pre-load is applied to the respective bush main bodies 6 in the axial direction. When an input is produced in the direction of wrenching under the aforesaid condition, the cylindrical member 2 is mostly displaced relatively roughly in the radial direction at its open end sections 2a with respect to each inner cylinder 4, each bush main body 6 in the vicinities of the open end sections of the cylindrical member 2 at each rising section 4a of inner cylinders 4 is thereby subjected to tension and compression. At this time, the provision Of each recessed section 5a at the open end sections of the cylinder members for the respective outer cylinders 5 enables the thickness of each bush main body 6 at this sections to be thinned, and also enables stiffness in the direction of wrenching to be enhanced with rubber's stiffness increased.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a bush assembly for swingably connecting a plate member and a tubular member, and is particularly used for connecting a suspension arm and a vehicle body in a vehicle suspension. Bush assembly.

[0002]

2. Description of the Related Art Conventionally, as a bush assembly used for a connecting portion between a suspension arm and a vehicle body in a vehicle suspension, for example, there is one described in Japanese Utility Model Laid-Open No. 11244/1990. This bush assembly is arranged between a pair of spaced plate members together with a tubular member, and comprises two bush members inserted into the tubular member.

Each of the bush members is bonded to an inner cylinder having a tubular portion extending in the axial direction of the tubular member and a rising portion extending outward in the radial direction from one end of the tubular portion, and an outer peripheral surface of the inner barrel. And a bushing body which is a tubular rubber and has an overhanging portion that can be compressed between the end surface of the tubular member and the flange portion. Further, the pair of bush members are provided by being inserted into the tubular member from the other end side of the tubular portion of each inner cylinder, and when not compressed in the axial direction, with the one plate member of one rising portion. The free length from the contact surface to the contact surface of the other rising portion with the other plate member is set longer than the interval between the pair of plate members, and is configured to be compressible to that interval.

Here, the pair of plate members constitutes, for example, a bracket on the vehicle body side, a retainer of a strut bar, a washer, and the like, and the tubular member constitutes, for example, an eye provided at the end of the suspension arm. Then, a predetermined preload is introduced into the bush assembly by inserting the pair of bush members coaxially into the tubular member and compressing them. This makes it possible to impart linearity to the spring characteristics while maintaining the bush hardness low.

[0005]

In the bush assembly having the above-mentioned structure, when it is desired to increase the rigidity in the twisting direction, the hardness of the entire rubber is conventionally increased or the thickness of the entire rubber is reduced. And deal with it. However, this coping method has a problem that the durability of the rubber in the twisting direction is deteriorated.

The weakest part of the rubber in terms of durability is
It is an overhanging portion that is an end portion that is farthest in the radial direction from the rotating shaft when twisted. The present invention has been made in view of the above problems, and an object thereof is to increase the rigidity in the twisting direction without lowering the durability of rubber.

[0007]

In order to achieve the above object, a bush assembly of the present invention is arranged together with a tubular member between a pair of plate members facing each other with a predetermined space therebetween, and is coaxial with the tubular member. Each of the bush members is composed of a pair of bush members to be inserted, and each of the bush members has a cylindrical rubber material interposed between an inner cylinder and an outer cylinder that are coaxially arranged. The end portion side facing the plate material of the above rises radially outward, and each of the outer cylinders forms a flange portion that extends radially outward on the plate material side and can abut the cylinder member end surface. In the bush assembly, the thickness of the rubber of each of the bush members is thin at the positions near both ends of the tubular member.

For example, the vicinity of the rising position of the flange portion on the inner peripheral surface of the outer cylinder of each bush member is projected toward the inner cylinder along the circumferential direction. Alternatively, the outer peripheral surface of the inner cylinder, which faces the vicinity of the end of the tubular member in the radial direction, is projected along the circumferential direction toward the vicinity of the end of the tubular member.

[0009]

In consideration of the relative displacement of the tubular member with respect to the inner cylinder when a load in the twisting direction is input to the bush assembly, the displacement near the both ends of the tubular member is largest. Therefore, for the input in the twisting direction,
The rubber portion located in the vicinity of both end portions of the tubular member is compressed or pulled to receive the rubber member.

In view of this, in the present invention, the load in the twisting direction can be applied without reducing the thickness of the whole rubber, particularly the thickness of the end portion, that is, without deteriorating the durability of the rubber against the input in the twisting direction. Only the thickness of the rubber in the portion where the relative displacement when input is large is reduced to increase the rigidity in the bending direction.

[0011]

Embodiments of the present invention will be described with reference to the drawings.
First, the structure will be described. As shown in FIG. 1, a bush assembly is arranged together with a tubular member 2 between a pair of plate members 1 facing each other with a predetermined gap. The bush assembly is
It is composed of a pair of bush members 3.

The pair of plate members 1 are, for example, brackets fixed to the vehicle body, and the tubular member 2 is an eye provided at the end of the suspension arm. The pair of bush members 3 are formed in the same shape and are inserted into the tubular member 2 symmetrically and coaxially. Each of the bush members 3 includes an inner cylinder 4 and an outer cylinder 5, and a bush body 6 made of rubber and interposed between the cylinders 4 and 5.
It is composed mainly of and.

The inner cylinder 4 extends in the axial direction of the cylinder member 2, and the end side outer peripheral surface side in the plate material 1 direction is formed into a taper shape whose diameter increases toward the end surface direction to form a rising portion 4a.
An outer cylinder 5 is arranged coaxially with the inner cylinder 4 on the outer peripheral side of the inner cylinder 4, and the outer cylinder 5 is a rising portion 4 a of the inner cylinder 4.
To the vicinity of the rising position in the
A ring-shaped recess 5a is formed so as to be recessed toward the inner cylinder 4 along the circumferential direction, and an outward flange portion 5b is formed so as to extend radially outward continuously from the recess 5a.

Further, the bush body 6 is formed in a tubular shape, the inner peripheral surface of which is vulcanized and adhered to the outer peripheral surface of the inner cylinder 4, and the outer peripheral surface thereof is the inner peripheral surface of the outer cylinder 5. It is interposed between both cylinders 4 and 5 by being vulcanized and bonded to the plate material 1 end side, that is, the rising portion 4a of the inner cylinder 4 and the flange portion 5b of the outer cylinder 5.
The portion sandwiched between the two extends radially outward to form the overhanging portion 6a.

A tubular insert 7 is coaxially embedded in the bush body 6 along the extending direction thereof to reinforce the bush body 6. Then, the pair of bush members 3 having the above-described configuration are coaxially fitted and inserted from both end opening sides of the tubular member 2, and the flanges of the outer cylinders 5 are attached to the tubular member 2.
Of the bush members 3 are pressed against each other so that the mutually facing opening end surfaces of the inner cylinders 4 of the bush members 3 come into contact with each other, so that each bush body 6 is preloaded in the axial direction. The bush members 3 to the pair of plate members 1
Place in between. Then, a bolt 8 is inserted between the bush members 3 and the pair of plate members 1 and fixed by bolts to be assembled.

When an axial input is generated in this state, the overhanging portion 6a of the bush body 6 compresses and pulls in the axial direction to support the load. When an input in the prying direction occurs, as shown in FIG. 2, the tubular member 2 is displaced relative to the inner cylinder 4 on the side of the open end portion 2a most in the radial direction. On the other hand, mainly the vicinity of the opening end of the tubular member 2 and the rising portion 4 of the inner cylinder 4
Bush body 6 of the part sandwiched near the rising to a
However, it will be received by being stretched and compressed.

At this time, in this embodiment, the recess 5a is provided in the portion of the outer cylinder 5 located on the inner peripheral surface of the opening end of the cylindrical member 2, so that the thickness of the bush main body 6 at that portion is set thin. Therefore, the rigidity of the rubber in that portion is high, and the rigidity in the twisting direction in the bush assembly is set higher than in the conventional case. At this time, with respect to the input in the twisting direction, the overhanging portion 6a farthest from the rotation axis is provided.
Is the weakest part in terms of durability, but in the present embodiment, when the rigidity in the twisting direction is improved, the overhanging part 6a is
Since it is not necessary to reduce the wall thickness or increase the hardness, the durability of the overhanging portion 6a is not deteriorated.

In the above embodiment, the concave portion 5a is formed in the outer cylinder 5.
By forming the above, the thickness of the rubber in the vicinity of both ends of the tubular member 2 is made thin, but by fixing a convex portion along the circumferential direction to the inner surface of the outer cylinder 5, the thickness of the rubber is made thin. Good. Or
As shown in FIG. 3, on the outer peripheral surface of the inner cylinder 4 that faces the vicinity of both ends of the cylinder member 2 in a substantially radial direction, a protrusion 4b that protrudes toward the end of the cylinder, that is, the vicinity of the bend of the outer cylinder 5, It may be formed in a ring shape along the circumferential direction to reduce the wall thickness of the above portion and improve the rigidity in the twisting direction.

Alternatively, the thickness of the insert 7 embedded in the rubber is made thicker only in a portion which can face the vicinity of both ends of the cylindrical portion in the substantially radial direction, and the thickness of the rubber in the above portion is relatively increased. The thickness may be reduced.

[0020]

As described above, in the bush assembly of the present invention, the rigidity in the twisting direction can be improved without causing the deterioration of the durability of the rubber due to the input in the twisting direction, simply by changing the shape. It becomes possible.

[Brief description of drawings]

FIG. 1 is a cross-sectional side view showing a bush assembly of an embodiment according to the present invention.

FIG. 2 is a diagram showing a behavior of the tubular member with respect to an input in a twisting direction according to the embodiment of the present invention.

FIG. 3 is a partial cross-sectional side view showing a bush assembly according to a second embodiment of the present invention.

[Explanation of symbols]

 1 plate material 2 cylinder member 3 bush member 4 inner cylinder 4a rising portion 5 outer cylinder 5a recess 5b flange portion 6 bush body

Claims (3)

[Claims] 1. A pair of bush members which are disposed between a pair of plate members facing each other with a predetermined space therebetween and are coaxially inserted into the tubular member, and the bush members are coaxially arranged. A tubular rubber material is interposed between the inner cylinder and the outer cylinder provided, and the end portions of the outer surfaces of the inner cylinders, which face the plate material, stand up radially outward and In a bush assembly in which each outer cylinder extends radially outward on the plate material side to form a flange portion capable of contacting the end surface of the cylinder member, the thickness of rubber of each bush member is set to be equal to both ends of the cylinder member. A bush assembly characterized by being thinned at a position near the portion. 2. The bush assembly according to claim 1, wherein the vicinity of the rising position of the flange portion on the inner peripheral surface of the outer cylinder of each bush member is projected toward the inner cylinder along the circumferential direction. 3. The bush according to claim 1, wherein an outer peripheral surface of the inner cylinder, which faces the vicinity of the end of the cylindrical member in a substantially radial direction, is projected along the circumferential direction toward the vicinity of the end of the cylindrical member. Assembly.