JP2005030599A - Resilient bushing - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a resilient bushing which is excellent in riding comfort and driving stability and low in deterioration of molecule structure of an elastic body and spring constant. <P>SOLUTION: An inner cylinder 1 and an outer cylinder 2 concentrically disposed with each other are connected by the elastic body 3. Spaces 4, 4 are formed on both sides in the X direction which is the lengthwise direction in a vehicle. Intermediate plates 6, 6 are embedded at approximately intermediate positions in the radial direction in the elastic bodies 3 positioned in both sides with interposing a Y-direction inner cylinder 1 coinciding the vehicle width direction between the two sides. The intermediate plates 6, 6 are bent toward each other with an arc of a radius smaller than that of the arc about the axis of the inner cylinder in a central portion of the width direction. The plates 6, 6 are formed into a substantial dog-leg shape in cross section having a bending angle (α) to an opposed parallel surface ranging from 15° to 25°. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to an elastic bush used by being incorporated in a suspension of an automobile, and more particularly to a saddle type elastic bush.

    In order to alleviate vehicle body vibration, an elastic bush (so-called suspension bush) as shown in FIG. A1) (A2) is used. Of these two elastic bushes (A1) and (A2), the second elastic bush (A2) on the rear side of the vehicle is often used in the vertical axis type, that is, the vertical type.

  Such an elastic bushing is desired to have a high spring constant in the vehicle width direction and a low spring constant in the vehicle front-rear direction from the characteristics such as ride comfort and steering stability of the vehicle. For this reason, as shown in FIGS. 6 and 7, the inner cylinder (11) and the outer cylinder (12) are coupled by the elastic body (13), and the elasticity of both side portions corresponding to the vehicle longitudinal direction (X direction in the figure). A space (14) (14) that penetrates the body (13) in the axial direction between the inner and outer cylinders is provided, and the radius in the elastic body (13) at the position corresponding to the vehicle width direction (Y direction in the figure) The thing which embed | buried the intermediate | middle board (16) (16) has appeared in the direction intermediate position (for example, patent document 1, patent document 2).

  The elastic bushing lowers the spring constant (Xa) in the X direction (vehicle longitudinal direction) by the voids (14) and (14), and the intermediate plates (16) and (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 large (5 or more).

Conventionally, the intermediate plate (16) (16) embedded in the elastic body (13) has a cross-sectional shape that is a simple arc concentric with both the inner and outer cylinders as shown in FIG. Or what has a simple flat form like FIG. 7 is common.
Japanese Utility Model Publication No. 6-76730 JP-A-62-188832

    However, for example, when a load in the X direction is applied, in the case of an arc-shaped intermediate plate, both intermediate plates (16) and (16) are deformed so as to spread in a letter C shape, and the intermediate plate (16) The tensile strain of the portion B, which is the space end between the both ends and the outer cylinder (12), is increased. Further, in the case of a flat intermediate plate, the free length of the a-part cannot be taken sufficiently. For this reason, stress concentration occurs in the portion B due to repeated loading, 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 the spring constant ratio in the X direction (vehicle front-rear direction) and the Y direction (vehicle width direction) can be set large, so that both ride comfort and steering stability can be achieved. It has excellent characteristics, and the tensile strain due to load in the X direction is small, the molecular structure of the elastic body and the durability of the spring constant are excellent, and even if the load direction is slightly deviated, there is little sudden deterioration of the spring constant. It is an object of the present invention to provide an elastic bush that can be used favorably as a placement type.

    The present invention solves the above-described problem, and the inner cylinder and the outer cylinder arranged concentrically are coupled by an elastic body interposed between the two, and both side positions in one direction sandwiching the inner cylinder Is provided with a space penetrating in the axial direction, and a pair of intermediate plates facing each other at substantially the middle position in the radial direction are embedded in the elastic bodies at both sides sandwiching the inner cylinder in a direction orthogonal to the one direction. An elastic bushing, wherein the pair of intermediate plates bend toward the opposite sides with an arc having a smaller radius than the arc centered on the inner cylinder axis at the center in the width direction, and a bending angle with respect to the opposing parallel plane (Α) has a cross-sectional shape of approximately 15 ° to 25 °.

    According to the present invention having the above-described configuration, the spring constant in the direction (X direction) in which the void is provided across the inner cylinder is low, and the spring constant in the direction (Y direction) perpendicular thereto is the elastic body. Since the intermediate plate is embedded in the upper portion, the height is increased, and the spring constant ratio in both directions is set large.

  In particular, since the pair of intermediate plates embedded in the elastic body with the inner cylinder sandwiched between them has a generally U-shaped cross section with a predetermined bending angle as described above, the gap between both ends of the intermediate plate and the outer cylinder When the load in the direction (X direction) where the space is provided is moderately long and the free length of the space portion (i) is moderately long, a conventional flat plate or arcuate intermediate plate is embedded. Compared to the two, the intermediate plates are prevented from being deformed to spread in the shape of a letter C, the tensile strain of the part a is small, and the molecular structure of the elastic body and the spring constant are less deteriorated in the part a. Become.

  In addition, the decrease in the spring constant when the load loading direction in the direction in which the intermediate plate is embedded (Y direction) is shifted in the circumferential direction is small, and sufficient rigidity can be secured against a slight shift in the load loading direction.

    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 large, and riding comfort and steering stability are good. In addition, deformation and tensile strain under load are small and stress concentration is unlikely to occur, and there is little deterioration of the molecular structure and the honey constant of the elastic body, which can further improve handling stability when turning the vehicle, etc. It can be suitably used as a type of bush.

  Next, embodiments of the present invention will be described with reference to the drawings.

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

  In the figure, the elastic bush (A) has an inner cylinder (1) and an outer cylinder (2) which surrounds the inner cylinder (1) with a predetermined interval between them. The rubber-like elastic bodies (3) arranged therebetween are integrally connected by means of vulcanization adhesion molding.

  (4) (4) includes both inner and outer cylinders (1) sandwiching the elastic body (3) at both side positions in one direction (X direction) sandwiching the inner cylinder (1) and orthogonal to the inner cylinder axis. ) A void formed so as to penetrate between (2) in the axial direction. (5) (5) is an elastic body as a stopper that restricts relative excessive deformation of the inner cylinder (1) and the outer cylinder (2) in the X direction.

  (6) A pair of (6) is embedded so as to be opposed to each other with the inner cylinder (1) in between at a substantially radial position in the elastic body (3) at a position corresponding to the direction (Y direction) orthogonal to the X direction. These intermediate plates (6) and (6) are also inserted and 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) and (6) have a radius smaller than an arc centered on the axis of the inner cylinder (1) at the center in the width direction, that is, the center in the width in the bushing circumferential direction. The cross section has a substantially square shape bent toward the opposite side with a circular arc, and the bending angle (α) with respect to the opposite parallel plane in the X direction is set to 15 ° to 25 °. That is, the central angle of the arc-shaped bent portion (6a) is twice (2α) the bent angle (α), and both side portions continuous from the bent portion (6a) extend in the tangential direction.

  As for the arc of the bent portion (6a) of the intermediate plate (6), it is an arc having a radius equal to or larger than the arc centered on the inner cylinder axis, because it is bent into a substantially square shape. The effect cannot be obtained and the bent shape is also deteriorated. In addition, when the arc has a very small radius, the bent portion is rounded and stress concentration tends to occur. Therefore, it is desirable that the arc of the bent portion (6a) is an arc having a radius smaller than the arc centered on the inner cylinder axis center with the center of curvature inside the inner cylinder outer peripheral surface. And it is desirable to embed the elastic body (3) at a position where the thickness of the elastic body (3) becomes substantially the same inside and outside the bent portion (6a).

  As for the bending angle (α) of the intermediate plate (6), if the angle (α) is smaller than 15 °, there is no difference from the flat intermediate plate, and the angle (α) is larger than 25 °. Distortion is likely to occur and the expected effect cannot be obtained. Therefore, the bending angle (α) is preferably set to 15 ° to 25 °.

  The above-mentioned elastic bush (A) is used as a second type of elastic bush at the connecting portion of the lower arm in the suspension to the vehicle body side frame as shown in FIG. The X direction in which (4) is provided is arranged in the vehicle longitudinal direction, and the Y direction in which the intermediate plates (6) and (6) are buried is arranged in the vehicle width direction.

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

  Further, with respect to vibrations and external forces in the Y direction, that is, in the vehicle width direction, the elastic body (3) at both side positions in the Y direction is compressed and pulled, and relative to the relative movement between the inner cylinder (1) and the outer cylinder (2). In addition to the increase in resistance, the intermediate plate (6) (6) is embedded in the elastic body (3), and the spring constant becomes several steps larger than in the X direction. The spring constant ratio (Ya / Xa) is 7 or more. Therefore, steering stability can be improved.

  In particular, since the intermediate plate (6) (6) has a substantially square cross section at a predetermined angle as described above, the intermediate plate (6) is formed between both ends of the intermediate plate (6) and the outer cylinder (2). Deformation when a load in the X direction is applied to the portion i that is the end of the void and when the load in the X direction is applied, that is, both the intermediate plates (6) and (6) tend to spread in the shape of a square. Deformation is suppressed, and the tensile strain of the portion a is small, so that stress concentration hardly occurs, and changes in the molecular structure and spring constant of the elastic body in the portion can be suppressed.

  Also, the change in the spring constant when the load direction in the Y direction is shifted in the circumferential direction is small compared to the case where a simple flat plate or arcuate intermediate plate is embedded, and a slight shift in the load direction. Sufficient rigidity (spring constant) can be secured.

  For example, an elastic bush of the same size manufactured under the same conditions except for the intermediate plate, in which a substantially square-shaped intermediate plate having a bending angle (α) of 20 ° in FIG. The endurance test was carried out as follows for the one in which the arc-shaped intermediate plate in FIG. 6 was embedded (Comparative Example 1) and the one in which the flat plate-shaped intermediate plate in FIG. 7 was embedded (Comparative Example 2).

  That is, with the outer cylinder fixed, the load is ± 300 kg and the twist angle (θ) is 12 ° with respect to the inner cylinder. A load is repeatedly applied in the X direction in the figure, and the fracture occurs due to deterioration of the molecular structure of the elastic body. When the number of times until the occurrence of was found, it was as shown in Table 1 below.

このように、本発明の実施例のものは、比較例１および比較例２の従来品に比して２〜５倍も弾性体の分子構造及びバネ定数の劣化が少なかった。

As described above, the examples of the present invention were less deteriorated in the molecular structure and the spring constant of the elastic body by 2 to 5 times than the conventional products of Comparative Examples 1 and 2.

  In addition, about the thing of an Example and the thing of the comparative example 1, when the difference of the space | interval (B) in the normal state between the edge parts of both intermediate | middle plates and the space | interval (B ') at the time of a load load was measured, it implemented. In the case of Example, it was +2 mm, but in the case of Comparative Example 1, it was 4 mm. Therefore, in the case of the comparative example 1, it is thought that the tensile strain of the A part at the time of load application becomes large, and the molecular structure of the elastic body and the deterioration of the spring constant are larger than in the example.

  Aside from the above, when the durability test was performed on the intermediate plate having a substantially square shape and a bending angle of 30 °, the result was the same as in Comparative Example 1.

It is a top view which shows the elastic bush of one Example of this invention. It is sectional drawing of the II line | wire of FIG. It is sectional drawing of the II-II line | wire of FIG. It is sectional drawing at the time of the load load of a X direction. It is a schematic plan view of the usage state of a conventional elastic bush. It is sectional drawing (a) at the normal time which shows an example of the conventional elastic bush, and sectional drawing (b) at the time of a load load. It is sectional drawing which shows the other example of the conventional elastic bush.

Explanation of symbols

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

Claims (1)

The inner cylinder and the outer cylinder arranged concentrically are coupled by an elastic body interposed between the two, and a space penetrating in the axial direction is provided at both side positions in one direction across the inner cylinder, An elastic bushing in which a pair of intermediate plates facing each other in the radially intermediate position are embedded in elastic bodies at both sides of the inner cylinder in a direction perpendicular to one direction,
The pair of intermediate plates bend toward the opposite sides with an arc having a smaller radius than the arc centered on the inner cylinder axis at the center in the width direction, and the bending angle (α) with respect to the opposing parallel surface is 15 °. An elastic bushing having a substantially square shape with a cross section of ˜25 °.

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