JPH06129460A - Vibro-isolating bush - Google Patents

Abstract

PURPOSE:To reconsile control stability and cushionability by installing an insert and a vibrationproof rubber body in space between an inner cylinder and an outer cylinder, and forming the central part of an inner cylinder outer circumferential surface into a spherical convex and an insert inner circumferential surface into a spherical concave along the convex, respectively. CONSTITUTION:An inner cylinder 2 is installed in an outer cylinder 2, while an outer circumferential surface 11a of a bulge part 11 at the central part is formed into a spherical convex, and a ringlike insert 3 being well in slidability is installed in space between the outer circumferential surface 11 a and an inner circumferential surface of the outer cylinder 2, and the outer circumferential surface 3b is formed into a plane in contact with the inner circumferential surface of the outer cylinder 2, while the inner circumferential surface 3a into a spherical concave along the outer circumferential surface 11a, respectively, and two vibrationproof rubber bodies 4A, 4B are inserted into space between both the openings of the outer cylinder 2 and an inner cylinder 1. When a shaft straight directional vibration is inputted, the bulge part 11 comes into contact with the outer cylinder 2 via the insert 3, maintaining the rigidity of a vibro-isolating bush, and control stability is securable. When the axial vibration is inputted, the insert 3 slides on the inner circumferential surface of the outer cylinder 2 in a state of being engaged with the bulge part 11, whereby a spring constant of the vibro- isolating bush becomes lessened by each deformation of the vibrationproof rubber bodies 4A, 4B, so good cushionability is thus securable.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vibration damping bush, and more particularly to a vibration damping bush suitable for holding a suspension arm of a vehicle suspension.

[0002]

2. Description of the Related Art FIG. 5 shows a conventional anti-vibration bush used for this type of application, which includes an outer cylinder 2 fixed to a vehicle frame and a suspension arm S inserted through the center thereof.
And an inner cylinder 1 having one end thereof connected, and a vibration-proof rubber body 8 having a constant thickness is formed in a cylindrical shape on the outer circumference of the inner cylinder 1, and the vibration-proof rubber body 8 is press-fitted and fixed in the outer cylinder 2. is there.

[0003]

By the way, the above-mentioned anti-vibration rubber body has a large rigidity in the direction perpendicular to the axis of the suspension arm in order to ensure steering stability, and is sufficiently small in the axial direction in order to enhance the cushioning property. It must have spring properties.

However, in the conventional vibration-proof bushing described above, if the spring constant of the vibration-proof rubber body is increased in order to ensure steering stability, the cushioning property will be impaired, and it is difficult to achieve both steering stability and cushioning property. It was

The present invention has been made to solve the above problems, and an object of the present invention is to provide an anti-vibration bush capable of achieving both steering stability and cushioning properties.

[0006]

One structure of the present invention will be described. An inner cylinder 1 and an outer cylinder 2, which are concentrically arranged and connected to a vibrating body, and an inner cylinder 1 and an outer cylinder 2, respectively. A ring-shaped insert 3 which is inserted into a cylindrical space between the inner peripheral surface 3a and the outer peripheral surface 3b and which are sliding surfaces in contact with the outer peripheral surface of the inner cylinder 1 and the inner peripheral surface of the outer cylinder 2, respectively. A ring-shaped anti-vibration rubber body 4A, 4B, which is joined between both ends of the inner circumference of the outer cylinder 2 and both ends of the outer circumference of the inner cylinder 1, and is axially spaced from both end surfaces of the insert 3. Then, the spherical convex surface 11a is formed in the central portion on the outer peripheral surface of the inner cylinder 1, and
The inner peripheral surface 3a of the insert 3 is a spherical concave surface along the convex surface 11a.

To explain another structure of the present invention, a ring-shaped spacer 21 having an inner peripheral surface having a spherical concave surface 21a is fixed to the center of the inner peripheral surface of the outer cylinder 2, and the insert 3
The outer peripheral surface 3b is a spherical convex surface along the concave surface 21a.

[0008]

In each of the above constructions, when vibration in the direction perpendicular to the axis is input, the outer peripheral surface of the inner cylinder 1 is in contact with the inner peripheral surface of the outer cylinder 2 via the insert 3 (or the spacer 21). This prevents the movement. Therefore, the rigidity of the vibration-proof bushing in this direction is kept sufficiently large, and the steering stability is kept good.

When axial vibration is input, the insert 3
Freely reciprocates in the axial direction within a certain range according to the vibration input along the outer circumference of the inner cylinder 1 or the inner circumference of the outer cylinder 2. At this time, the spring force of the anti-vibration bush is determined only by the anti-vibration rubber bodies 4A and 4B, and if the spring constant of the anti-vibration rubber bodies 4A and 4B is set sufficiently small, good cushioning properties can be obtained.
The inner cylinder 1 is also capable of torsional displacement, which also ensures cushioning.

Further, in addition to the vibration in the axial direction and the like, a twisting vibration may be input. In this case, the inner cylinder outer peripheral surface 11a and the insert inner peripheral surface 3a, or the insert outer peripheral surface 3b and the spacer 21 are connected. Vibrations are absorbed by sliding on the spherical convex surface and concave surface of each other, an increase in frictional resistance when the insert 3 moves in the axial direction is avoided, and its smooth movement is guaranteed.

[0011]

[Embodiment 1] In FIG. 1, an inner cylinder 1 which is slightly longer than the outer cylinder 2 is arranged at the axial center of the outer cylinder 2. The outer peripheral surface 11a of 11 is a spherical convex surface. The outer peripheral surface 11a of the bulging portion 11
A ring-shaped insert 3 is provided between the inner peripheral surface of the outer cylinder 2 and the inner peripheral surface of the outer cylinder 2. The insert 3 is made of a resin material such as polyacetal having good slidability, and is separated at one position in the circumferential direction. The outer peripheral surface 3b of the insert 3 forms a flat surface in contact with the inner peripheral surface of the outer cylinder 2, and the inner peripheral surface 3a is a spherical concave surface along the outer peripheral surface of the bulging portion 11.

Anti-vibration rubber bodies 4A and 4B are inserted between both openings of the outer cylinder 2 and the inner cylinder 1. Anti-vibration rubber body 4
A and 4B are ring bodies that expand and incline inward in an umbrella shape. Metal sleeves 71 and 72 are joined to the inner and outer peripheral surfaces of the ring bodies. It is press-fitted and fixed. The sleeve 72 and the end surface of the insert 3 are separated by a predetermined dimension m.

The outer cylinder 2 is press-fitted and fixed in a circular holder (not shown) provided on the vehicle frame.

In the vibration-proof bush having the above structure, the inner cylinder 1
When vibration in the direction perpendicular to the axis is input from a suspension arm (not shown) that is inserted and fixed to the outer cylinder 2, the bulging portion 11 of the inner cylinder 1 contacts the outer cylinder 2 via the insert 3 to prevent displacement.
As a result, the rigidity of the anti-vibration bush is maintained sufficiently high in this direction, and steering stability is ensured.

When the axial vibration is input from the suspension arm, the insert 3 is freely slid on the inner peripheral surface of the outer cylinder 2 within the range of the dimension m while being engaged with the bulging portion 11 of the inner cylinder 1. The spring constant of the anti-vibration bush at this time becomes sufficiently small only by the deformation of the anti-vibration rubber bodies 4A and 4B. Thus, good cushioning properties are secured in this direction, and riding comfort is improved.

The suspension arm may vibrate as shown by the arrow in the figure. In this case, however, the inner surface of the inner cylinder bulge 11 has a convex spherical surface 11a and the inner surface of the insert 3 has a concave shape. The spherical surface 3a freely slides to absorb the vibrations, the increase in frictional resistance is suppressed, and a smooth axial movement of the inner cylinder 1 is ensured.

[0017]

[Embodiment 2] The vibration-proof bush shown in FIG. 2 has the same basic structure as that of the above-mentioned Embodiment 1, and the rubber layer 5 is bonded to the inner peripheral surface of the insert 3 with a constant thickness. A sliding layer 6 having a small frictional resistance is formed on the inner peripheral surface of the rubber layer 5. The sliding layer 6 is formed, for example, by bonding a braided liner made of resin fiber having good slidability such as Teflon to the inner peripheral surface of the rubber layer 5. The inner peripheral surface of the rubber layer 5 is in elastic contact with the outer peripheral surface of the inner cylinder bulging portion 11 at a constant pressure.

The liner constituting the sliding layer 6 has a two-layer structure in which the contact surface with the bulging portion 11 is Teflon fiber and the bonding surface with the rubber layer 5 is Tetron fiber. Is also good.

According to this structure, in addition to the effect of the first embodiment, there is no play or noise when the inner cylinder 1 is moved. If the rubber layer 5 is made appropriately thin, the rigidity of the vibration-proof bushing is maintained sufficiently high in this direction, steering stability is ensured, and the elasticity of the rubber layer 5 reduces the cushioning property in the axial direction. Can be avoided.

[0020]

[Embodiment 3] FIG. 3 shows another vibration-proof bushing structure having the same effect as that of Embodiment 1. In the figure, a ring-shaped insert 21 made of a resin material having good slidability is slidably fitted on the outer circumference of the inner cylinder 1 having a constant diameter, and the inner circumference thereof is a flat surface along the outer circumferential surface of the inner cylinder 1. The outer circumference is a spherical convex surface. A predetermined dimension m is secured between the end portion of the insert 3 and the sleeve 71 on the inner circumference of the vibration-proof rubber bodies 4A and 4B.

On the other hand, a ring-shaped spacer 21 is arranged at the center of the inner periphery of the outer cylinder 2 in contact with the inner peripheral surface, and sleeves 72 on the outer periphery of the vibration-proof rubber bodies 4A, 4B are pressed against both ends thereof for positioning. It is fixed. The inner peripheral surface 21a of the spacer 21 is a spherical concave surface along the outer peripheral surface. The other structure is the same as that of the first embodiment.

In such a structure, the insert 3 on the outer circumference of the inner cylinder 1 and the spacer 21 on the inner circumference of the outer cylinder 2 are brought into contact with each other in response to the vibration input in the axial direction, and the rigidity of the vibration-proof bushing is maintained sufficiently large in this direction. As a result, steering stability is ensured.

With respect to the axial vibration input, the insert 3 engages with the spacer 21 and freely moves on the outer peripheral surface of the inner cylinder 1 within the range of the above-mentioned dimension m, and good cushioning property is obtained in this direction. Is ensured and the riding comfort is improved.

The spacer 2 is also provided to prevent twisting vibrations.
The convex spherical surface 3a on the outer periphery of the insert 3 freely slides against the concave spherical surface 21a of No. 1 to absorb the vibration and suppress the increase of frictional resistance, thereby ensuring the smooth axial movement of the spacer 3 (inner cylinder). To be done.

[0025]

Fourth Embodiment If the rubber layer 5 and the sliding layer 6 as shown in the second embodiment are formed on the inner peripheral surface 21a of the spacer 21 having the same structure as the third embodiment as shown in FIG. It is possible to prevent backlash and abnormal noise when the cylinder 1 is moved, and to avoid deterioration of cushioning property in the axial direction.

[0026]

As described above, according to the vibration-proof bushing of the present invention, it is possible to simultaneously realize a large rigidity in the axial direction and a sufficiently small spring characteristic in the axial direction. And the ride comfort can be satisfied satisfactorily, and the effect does not deteriorate even when a twisting vibration is input.

[Brief description of drawings]

FIG. 1 is an overall vertical sectional view of an anti-vibration bush according to a first embodiment of the present invention.

FIG. 2 is an overall vertical sectional view of an anti-vibration bush according to a second embodiment of the present invention.

FIG. 3 is an overall vertical sectional view of an anti-vibration bush according to a third embodiment of the present invention.

FIG. 4 is an overall vertical sectional view of a vibration-proof bush according to a fourth embodiment of the present invention.

FIG. 5 is an overall vertical sectional view of a conventional vibration damping bush.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 inner cylinder 11 bulging part 11a spherical convex surface 2 outer cylinder 21 spacer 3 insert 3a inner peripheral surface 3b outer peripheral surface 4A, 4B anti-vibration rubber body

Claims (2)

[Claims] 1. An inner cylinder and an outer cylinder, which are concentrically arranged and are respectively connected to a vibrating body, and are inserted into a cylindrical space between the inner cylinder and the outer cylinder, and inner and outer peripheral surfaces thereof are A ring-shaped insert that is a sliding surface that contacts the outer peripheral surface of the inner cylinder and the inner peripheral surface of the outer cylinder, respectively, and is joined between both ends of the inner circumference of the outer cylinder and both ends of the outer circumference of the inner cylinder. It is provided with both end faces and a ring-shaped vibration isolating rubber body which is located at a distance in the axial direction, and a spherical convex surface is formed in the central portion on the outer peripheral surface of the inner cylinder, and the inner peripheral surface of the insert is the convex surface. Anti-vibration bush with spherical concave surface along 2. An inner cylinder and an outer cylinder, which are concentrically arranged and respectively connected to the vibrating body, a ring-shaped spacer fixed to the center of the inner peripheral surface of the outer cylinder and having an inner peripheral surface having a spherical concave surface, A ring-shaped insert that is inserted into the tubular space between the cylinder and the spacer, and the inner peripheral surface and the outer peripheral surface thereof are sliding surfaces in contact with the outer peripheral surface of the inner cylinder and the inner peripheral surface of the spacer, respectively. A ring-shaped anti-vibration rubber body, which is joined between both ends of the inner circumference of the outer cylinder and both ends of the outer circumference of the inner cylinder, and is axially spaced apart from both end surfaces of the insert, An anti-vibration bush characterized in that the peripheral surface is formed into a spherical concave surface, and the outer peripheral surface of the insert is formed into a spherical convex surface along the concave surface.