JPH09126259A - Elastic bush - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide ride comfortabless and stable controllability and to reduce deterioration of the molecule structure and the spring constant of an elastic body. SOLUTION: An inner cylinder 1 and an outer cylinder 2 which are concentrically disposed are joined by an elastic body 3 and spaces 4, 4 are made in both sides of the X-direction or the back-and-forth direction of a vehicle and intermediate plates 6, 6 are buried in a nearly intermediate position in a radial direction of the elastic body 3 and in both sides across the inner cylinder 1 and in both sides of the Y-direction or the width direction of the vehicle. The intermediate plates 6, 6 are bent toward the opposite side at the center of width direction with an arc of a smaller radius than an arc having a center at the axis of the inner cylinder and they are shaped like a dog leg in cross section with a bent angle (α) of 15 deg. to 25 deg. for opposite parallel planes.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an elastic bush used by being incorporated in a suspension of an automobile, and more particularly to a vertical type elastic bush.

[0002]

2. Description of the Related Art In order to reduce vibration of a vehicle body, a vehicle body and a suspension portion of a vehicle, for example, a lower arm supporting a wheel and a vehicle body side member such as a frame, are connected to a vehicle body and a suspension portion in order to reduce vehicle body vibration. As shown in Fig. 5, the elastic bush (A1) (A
2) is used. These two elastic bushes (A
1) (A2), the second elastic bush (A
Regarding 2), vertical shaft type, that is, vertical type is often used.

It is desired that such an elastic bush has a high spring constant in the vehicle width direction and a low spring constant in the vehicle front-rear direction in view of characteristics such as riding comfort and steering stability of the vehicle.
Therefore, as shown in FIG. 6 and FIG. 7, the inner cylinder (11) and the outer cylinder (12) are connected by the elastic body (13), and the elasticity of both side portions corresponding to the vehicle front-rear direction (X direction in the drawing) is increased. A hollow (14) (1) that penetrates the body (13) in the axial direction between the inner and outer cylinders.
4) is further provided, and an intermediate plate (1) is provided at an intermediate position in the radial direction within the elastic body (13) at a position corresponding to the vehicle width direction (Y direction in the drawing).
6) There are some in which (16) is buried (for example, Japanese Utility Model Laid-Open No. 6-76730 and Japanese Patent Laid-Open No. 188832/1987).

The elastic bush is provided in the space (14) (14).
The spring constant (Xa) in the X direction (vehicle front-rear direction) is reduced by using the intermediate plate (16) (16) in the Y direction (vehicle width direction).
The spring constant (Ya) is increased, and the spring constant ratio (Ya / Xa) in the X direction and the Y direction is set to a large value (5 or more).

Conventionally, the intermediate plates (16) and (16) embedded in the elastic body (13) have a cross-sectional shape which is a simple arc shape concentric with the inner and outer cylinders as shown in FIG. In general, it is a flat plate as shown in FIG.

However, when a load is applied in the X direction, for example, in the case of an arc-shaped intermediate plate, both intermediate plates (16) (1
6) is deformed so that it spreads in a V shape, and the intermediate plate (16)
The tensile strain of the a-part, which is the end of the space between both ends of the outer cylinder and the outer cylinder (12), increases. Further, in the case of a flat plate-shaped intermediate plate, the free length of the a portion cannot be sufficiently obtained. Therefore, the stress is concentrated in the portion (a) due to the repeated load, and the molecular structure and spring constant of the elastic body are likely to change.

The present invention has been made in view of the above, and it is possible to set a large spring constant ratio in the X direction (vehicle front-rear direction) and the Y direction (vehicle width direction), and to improve riding comfort and steering stability. In addition to excellent properties, the tensile strain due to the load in the X direction is small, and the durability of the molecular structure and spring constant of the elastic body is excellent, and the spring constant does not deteriorate sharply even if the load direction shifts slightly. In particular, the present invention provides an elastic bush that can be favorably used as a vertical placement type.

[0008]

DISCLOSURE OF THE INVENTION The present invention is to solve the above-mentioned problems, in which an inner cylinder and an outer cylinder arranged concentrically are connected by an elastic body interposed therebetween, and A space penetrating in the axial direction is provided at both sides of the inner cylinder in one direction, and the elastic bodies at both sides of the inner cylinder in the direction orthogonal to the one direction face each other at a substantially intermediate position in the radial direction. An elastic bush in which a pair of intermediate plates are embedded, wherein the pair of intermediate plates face toward each other with an arc having a radius smaller than an arc centered on the inner cylinder axis in the widthwise central portion. Bending and bending angle (α) with respect to the facing parallel plane is 15 °
It is characterized by having a substantially V-shaped cross section of -25 °.

[0009]

According to the present invention having the above structure, the spring constant in the direction in which the void is provided with the inner cylinder interposed (X direction) is low, and the spring constant in the direction orthogonal to this (Y direction). Is high because the intermediate plate is embedded in the elastic body, and the spring constant ratio in both directions is set to be large.

In particular, since the pair of intermediate plates embedded in the elastic body with the inner cylinder interposed therebetween have a substantially V-shaped cross section at the predetermined bending angle as described above, both ends of the intermediate plate and the outer cylinder are formed. When the load in the direction in which the space is provided (X direction) is applied and the free length of the a part, which is the end of the space between the spaces, is moderately applied, the conventional flat plate-shaped or arc-shaped intermediate plate In comparison with the one in which the intermediate plate is embedded, the deformation that both intermediate plates try to spread in the shape of the letter “H” is suppressed, the tensile strain of the a portion is small, and the molecular structure and the spring constant of the elastic body in the a portion are reduced. Less deterioration.

Further, when the load-loading direction in which the intermediate plate is embedded (Y direction) is displaced in the circumferential direction, the spring constant is not significantly reduced, and sufficient rigidity is secured against a slight shift in the load-loading direction. it can.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is a plan view showing an elastic bush (A) according to one embodiment of the present invention, FIG. 2 is a sectional view taken along line II of FIG. 1, and FIG. 3 is taken along line II-II of FIG. FIG.

In the figure, the elastic bush (A) is formed by concentrically arranging an inner cylinder (1) and an outer cylinder (2) surrounding the inner cylinder (1) with a required interval. , And they are integrally connected by means of vulcanization adhesion molding through a rubber-like elastic body (3) arranged between them.

(4) (4) is a structure in which the elastic body (3) is pierced at both side positions in one direction (X direction) which sandwiches the inner cylinder (1) and is orthogonal to the inner cylinder axis. Cylinder (1)
It is a void formed so as to penetrate axially between (2). (5) (5) is an elastic body as a stopper that restricts the relative excessive deformation of the inner cylinder (1) and the outer cylinder (2) in the X direction.

(6) (6) are arranged so as to face each other with the inner cylinder (1) interposed therebetween at a substantially radial intermediate position in the elastic body (3) at a position corresponding to a direction (Y direction) orthogonal to the X direction. A pair of embedded intermediate plates. The intermediate plates (6) and (6) are also integrated by being embedded in the rubber-like elastic body (3) by means of vulcanization adhesion.

In the case of the present invention, the pair of intermediate plates (6).
(6) is bent toward the opposite sides with an arc having a radius smaller than the arc centered on the axial center of the inner cylinder (1) at the widthwise central portion, that is, the widthwise central portion. It has a substantially V-shaped cross section, and in particular, the bending angle (α) with respect to the opposing parallel surface in the X direction is set to 15 ° to 25 °. That is, the central angle of the arcuate bent portion (6a) is twice (2α) the bending angle (α), and both side portions continuous from the bent portion (6a) are tangentially extended.

Regarding the arc of the bent portion (6a) of the intermediate plate (6), if the arc has a radius equal to or larger than the arc centered on the inner cylinder axis, it bends in a substantially V shape. The effect of doing so cannot be obtained, and the bent shape also becomes worse. Further, in the case of an arc having a too small radius, the bent portion is angular and stress concentration is likely to occur. Therefore, it is preferable that the arc of the bent portion (6a) has a center of curvature inside the outer peripheral surface of the inner cylinder and has a radius smaller than the arc centered on the inner cylinder axis. And this bent part (6
It is desirable to embed the elastic body (3) inside and outside of a) at a position where the thickness of the elastic body (3) becomes substantially the same.

Regarding the bending angle (α) of the intermediate plate (6), when the angle (α) becomes smaller than 15 °, there is no difference from the flat intermediate plate, and the angle (α) is 25 °.
If it becomes larger, distortion tends to occur, and the expected effect cannot be obtained. Therefore, the bending angle (α) is 15 ° to 2
It is better to set it to 5 °.

The elastic bush (A) is, for example, as shown in FIG.
As shown in the figure, in the connection part of the lower arm in the suspension to the frame on the vehicle body side,
The elastic bush of the intermediate plate (6) (6) is embedded in the Y direction in which the X direction in which the voids (4) and (4) are provided is the vehicle longitudinal direction. Are arranged in the vehicle width direction.

In this use, the cavities (4) and (4) are formed on both sides of the inner cylinder (1) with respect to the vibration and the external force in the X direction, that is, the vehicle longitudinal direction. The spring constant in the X direction is relatively small, and elastic deformation due to relative movement easily occurs between the inner cylinder (1) and the outer cylinder (2). Therefore, good ride comfort can be obtained.

Further, with respect to vibrations and external forces in the Y direction, that is, the vehicle width direction, the elastic bodies (3) located on both sides in the Y direction are compressed,
The tensile force increases resistance to relative movement between the inner cylinder (1) and the outer cylinder (2), and in particular, the intermediate plates (6) and (6) may be embedded in the elastic body (3). Thus, the spring constant becomes several steps higher than that in the X direction, and the spring constant ratio (Ya / Xa) in the X and Y directions becomes 7 or more. Therefore, steering stability can be improved.

In particular, since the intermediate plates (6) and (6) have a substantially V-shaped cross section at a predetermined angle as described above, both ends of the intermediate plate (6) and the outer cylinder (2). Has a proper length at the a part which is the end part of the space between them, and is deformed when a load in the X direction is applied, that is, both intermediate plates (6) (6)
It is possible to suppress the deformation that tends to spread in a V shape, the tensile strain of the portion a is small and stress concentration is less likely to occur, and it is possible to suppress the change in the molecular structure and the spring constant of the elastic body in the portion.

Further, the change in the spring constant when the load direction in the Y direction deviates in the circumferential direction is smaller than that in the case where a mere flat plate-shaped or arc-shaped intermediate plate is embedded, and the change in the spring load direction is small. Sufficient rigidity (spring constant) can be secured even with a slight deviation.

For example, an elastic bush of the same size manufactured under the same conditions except for the intermediate plate and having a bending angle (α) of 20 in FIG.
With an embedded intermediate plate in the shape of a square V (example),
Durability tests were carried out as follows for the conventional product having the arc-shaped intermediate plate of FIG. 6 embedded (Comparative Example 1) and the plate having the flat intermediate plate of FIG. 7 embedded (Comparative Example 2). .

That is, with the outer cylinder fixed, the load on the inner cylinder is ± 300 kg, and the twist angle (θ) is 12 °.
Then, when a load was repeatedly applied in the X direction in the figure and the number of times until breakage occurred due to deterioration of the molecular structure of the elastic body was examined, the results are as shown in Table 1 below.

[0027]

[Table 1] As described above, in the examples of the present invention, the deterioration of the molecular structure and the spring constant of the elastic body was 2 to 5 times less than that of the conventional products of Comparative Examples 1 and 2.

For the example and the comparative example 1, the distance (B) between the end portions of both intermediate plates in the normal state,
When the difference from the interval (B ′) under load was measured, it was +2 mm in the case of the example, but 4 mm in the case of the comparative example 1.
There was also. Therefore, in the case of Comparative Example 1, it is considered that the tensile strain of the portion A under load is increased, and the deterioration of the molecular structure and spring constant of the elastic body is larger than that of the example.

Separately from the above, an endurance test was conducted on an intermediate plate having a substantially V shape and a bending angle of 30 °. As a result, the same result as in Comparative Example 1 was obtained.

[0030]

As described above, according to the elastic bushing of the present invention, the spring constant ratio in the X direction (vehicle front-rear direction) and the Y direction (vehicle width direction) can be set to be large, and the ride comfort and the steering can be improved. The stability is good, and the deformation and tensile strain under load are small so that stress concentration does not easily occur, the molecular structure of the elastic body and the deterioration of the honeycomb constant are small, and the steering stability when turning the vehicle is further improved. Therefore, it can be suitably used as a vertical type bush.

[Brief description of the drawings]

FIG. 1 is a plan view showing an elastic bush according to an embodiment of the present invention.

FIG. 2 is a cross-sectional view taken along line II of FIG.

FIG. 3 is a sectional view taken along line II-II of FIG.

FIG. 4 is a cross-sectional view when a load is applied in the X direction.

FIG. 5 is a schematic plan view of a conventional elastic bush in use.

FIG. 6 is a cross-sectional view (a) in a normal state and a cross-sectional view (b) under a load showing an example of a conventional elastic bush.

FIG. 7 is a cross-sectional view showing another example of a conventional elastic bush.

[Explanation of symbols]

 (1) Inner cylinder (2) Outer cylinder (3) Elastic body (4) Void (6) Intermediate plate

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Eiichi Kusama 1 Toyota Town, Toyota City, Aichi Prefecture, Toyota Motor Corporation (72) Inventor Fumihiro Moriwaki, 1 Toyota Town, Toyota City, Aichi Prefecture Toyota Motor Corporation

Claims (1)

[Claims] 1. An inner cylinder and an outer cylinder, which are concentrically arranged, are connected by an elastic body interposed therebetween, and the inner cylinder is sandwiched between the inner cylinder and the outer cylinder.
A space that penetrates in the axial direction is provided at both positions in the direction,
An elastic bushing in which a pair of intermediate plates facing each other at substantially radial intermediate positions are embedded in elastic bodies at both positions sandwiching an inner cylinder in a direction orthogonal to the one direction, wherein the pair of intermediate plates are: It has a circular arc with a radius smaller than the circular arc centered on the inner cylinder axis at the center in the width direction, bends toward the opposite sides, and has a bending angle (α) with respect to the parallel planes of 15 ° to 25 °. An elastic bush characterized by the shape of a letter.