JPH10238574A - Elastic bush - Google Patents

Abstract

PROBLEM TO BE SOLVED: To maintain spring characteristics in an axial direction and in a direction orthogonal to a shaft at an excellent value, reduce the occurrence of the strain of a rubber elastic substance when a wrenching force from an arm member is exerted, improve durability, and facilitate the regulation of spring properties. SOLUTION: A rubber elastic substance 3 is located between inner and outer cylinders 1 and 2, and a flange 8 is arranged at one end part. A gouged part 4 is formed in the flange part 31 of the elastic substance 3 as an elastic bush A mounted on an arm member 6 and in a portion, positioned facing the extension direction of the arm member 6. The arm member 6 forms a suspension arm extending longitudinally of a vehicle and a straightened part 5 is situated in the position in the vertical direction of a vehicle of the body part 32 of the elastic substance 3.

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 mainly in a suspension mechanism of an automobile.

[0002]

2. Description of the Related Art Conventionally, in a suspension of a vehicle such as an automobile, a connecting portion between a vehicle body and a suspension, for example, a connecting portion between an arm member of a suspension supporting a wheel and a vehicle body side member has elasticity for the purpose of cushioning. Bush is used.

For example, in a torsion beam type suspension of an automobile as shown in FIG. 6, a trailing arm (60) is pivotally supported on a vehicle body side by a bush portion (61) at a front end thereof, and a wheel (70) is provided at a rear end portion thereof. The bush portion (61) is provided with an elastic bush (A1) supported by a bush shaft (not shown) extending in and out of the vehicle.

As shown in FIG. 7, the above-mentioned elastic bush (A1) comprises a metal inner cylinder (101) and an outer cylinder (102) which are arranged concentrically by a vulcanization bonding means between both cylinders. The outer cylinder (102) is usually fixed to the end of an arm member (106) such as the trailing arm by press-fitting means or the like. The bush shaft is inserted into the inner cylinder (101) for use.

In order to improve the axial spring characteristics of the elastic bush, at least one end is provided with both inner and outer cylinders (1).
01) and (102) are provided with flanges (111) and (121) at different axial positions, and a rubber elastic body (103) is provided between the flanges (111) and (121).
In which the flange portion (131) is integrally extended.

Further, as shown in FIG. 8, two bushes (110) (110) having the same structure as described above are press-fitted into an arm member (106) with their ends having no flange facing each other. It is also considered to do.

[0007]

In the case of the elastic bush (A1) having the above-mentioned flange, although the spring characteristics in the axial direction are improved, the elastic member is twisted by the swing of the arm member (106) in the direction of the arrow in the drawing. May occur.

For example, the trailing arm (6
The elastic bush (A1) in (0) supports the arm so as to be able to swing up and down around the bush axis, but the arm swings even in a plane (substantially horizontal plane) including the arm and the bush axis. The rocking may cause the elastic bush (A1) to be twisted.

When such twisting occurs, compression and tension of the flange portion (131) of the rubber elastic body (103) occurs at a portion of the elastic bush (A1) facing the extending direction of the arm member (106). Deformation (strain) increases, for example, there is a problem that the outer peripheral portion of the flange portion (131) is protruded or an excessive tensile force is applied, and durability is reduced due to repeated fatigue.

In particular, as disclosed in Japanese Utility Model Laid-Open Publication No. Sho 60-194638, in order to adjust and improve the spring characteristic in the direction perpendicular to the axis, which is required according to the use condition, the relative position of the rubber elastic body between the inner and outer cylinders is increased. In the case of providing a space called “curling” at the opposite position to reduce the spring constant in the direction perpendicular to the axis where the curving portion exists, the same problem as described above occurs in the case of a bush of a type having a flange. Occurs.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and maintains the spring characteristics in the axial direction and the direction perpendicular to the axis in a good condition, and furthermore, compresses the rubber elastic body by the torsion force caused by the swing of the arm member. Excellent in reducing strain due to tension,
An object of the present invention is to provide an elastic bush whose durability can be improved and spring characteristics can be easily adjusted.

[0012]

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and a first aspect of the present invention is to provide a rubber elastic body interposed between an inner cylinder and an outer cylinder. An elastic bush provided with a flange at the portion and attached to the arm member, wherein a flange portion of the rubber elastic body is provided with a hollow portion at a portion facing the extending direction of the arm member. Features.

According to this elastic bush, since the cutout portion is provided at a portion facing the extending direction of the arm member where distortion due to the twist from the arm member is increased, the twisting force due to the swing of the arm member is reduced. It can be absorbed by the undercut, and large compression and tension do not act on the flange portion of the rubber elastic body, distortion is reduced, and durability is improved. On the other hand, the original spring characteristics can be maintained in the axial direction and the direction perpendicular to the axis.

According to a second aspect of the present invention, in the above-mentioned elastic bush, the arm member is a suspension arm, and a curving portion is provided at a position in the vehicle vertical direction of the main body of the rubber elastic body. .

According to this elastic bush, since the undercut portion is located opposite to the direction in which the suspension arm extends, the torsion force caused by the arm swinging in a substantially horizontal plane is effectively absorbed, and the durability is improved. Since the structure has an advantageous structure and the bulging portion is provided in the up-down direction of the vehicle, the up-and-down vibration of the suspension arm can be absorbed with a desired soft spring constant, and the riding comfort can be improved.

A third aspect of the present invention is characterized in that the two bushes according to the first or second aspect are attached to an arm member with their ends having no flange portion facing each other. And

In this case, since the flange having a recessed portion is provided at both ends thereof in a state of being attached to the arm member, the spring characteristics as the elastic bush, that is, the spring characteristics in the axial direction and the direction perpendicular to the axis are provided. Further, the spring characteristics against the twisting can be improved, and the adjustment and setting thereof can be easily performed.

According to a fourth aspect of the present invention, when the two bushes are opposed to each other, the inner cylinder of the other bush is press-fitted into the inner cylinder of the other bush.

In this case, the combination of the two bushes is facilitated, and the pre-compression for reducing the tensile strain can be easily applied to the flange portion of the rubber elastic body by the press-fitting amount of the inner cylinder. And the adjustment of the pre-compression amount becomes easy.

[0020]

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

FIG. 1 is a sectional view showing an elastic bush (A) according to a first embodiment of the present invention, and FIG. 2 is a front view of the elastic bush (A).

The elastic bush (A) comprises a metal cylindrical inner cylinder (1) and an outer cylinder (2) which are concentrically arranged.
The two cylinders are integrally connected via a rubber elastic body (3) arranged by a vulcanization bonding means, and a flange (8) is provided at one end in the axial direction. . That is, the inner cylinder (1) is formed to be longer than the outer cylinder (2), and the inner cylinder (1) and the end of the outer cylinder (2) are flanged at different axial positions at a required interval. (11) (21)
And a flange portion (31) of the rubber elastic body (3) sandwiched between the flanges (11) and (21).
Are extended, and these constitute the flange (8).

The outer cylinder (2) is attached to an end of an arm member (6) such as a trailing arm of a suspension by press-fitting means or the like. A bush shaft (not shown) supported by the vehicle body-side member is inserted into the inner cylinder (1).

The flange portion (31) of the rubber elastic body (3) is subjected to distortion caused by a twisting force caused by the arm member (6) due to opposing sides of the inner cylinder (1). At the portions facing the extending direction of the larger arm member (6), there are provided recesses (4) and (4) formed by recesses on the curved surface from the outer peripheral side.

If the circumferential spreading angle of the undercut (4) is larger than 90 °, the spring constant in the axial direction is reduced, and the effect of the provision of the flange is reduced, and the angle is smaller than 45 °. Then, since the effect of absorbing the torsion force is reduced, the undercut (4)
Is 45 ° to 9 ° around the axis in the circumferential direction as shown in FIG.
It has a spread (length) of an angle range (E) of 0 °.

In the undercut portion (4), the radius of curvature (Re) of the deepest point (P) in the cross section is set to 1 mm or more in FIG. Distance (C) from the inner peripheral surface to the deepest point (P) and distance (D) from the inner surface of the flange (11) of the inner cylinder (1) to the deepest point (P). , Respectively, flange portion (31) of rubber elastic body (3)
The thickness (T) and the distance (B) between the inner and outer cylinders (1) and (2) are preferably set to satisfy the following conditions. 0.2B ≦ C ≦ 0.8B D ≦ 0.5T (However, T> 30mm)
.

That is, if the radius of curvature (Re) of the deepest point (P) is less than 1 mm, cracks tend to be formed from the portion. If the distance (C) from the inner peripheral surface of the outer cylinder to the deepest point (P) is smaller than 0.2B, the undercut portion becomes shallow and the expected effect cannot be obtained.
If it is larger than 8B, the undercut becomes too deep and buckling is likely to occur when compression acts, causing a problem in durability. On the other hand, if the distance (D) from the flange surface of the inner cylinder to the deepest point (P) exceeds 0.5T, buckling is likely to occur during compression, which is not preferable.

(5) and (5) of FIG.
(2) is a bulge extending in parallel with the axis provided inside the main body (32) of the rubber elastic body (3), and the burrs (5) and (5) are provided with the arm member (6). In the case of a suspension arm such as a trailing arm extending in the vehicle front-rear direction shown in FIG. 6, the main body (32) is provided opposite to the vehicle vertical position as shown in FIGS. Can be Thereby, the spring constant is set low in the vehicle vertical direction.

The bulge (5) is set in an angular range (F) of 120 ° or less (usually 60 to 120 °) as viewed from the axis in the circumferential direction. In addition, as the bulging part (5),
In addition to the case where the rubber elastic body (3) is provided so as to penetrate in the axial direction as shown in the drawing, the rubber elastic body (3) may be provided without penetrating in the axial direction. An outer cylinder (2) is provided on the outer peripheral portion of the rubber elastic body (3).
It may be provided in the form of a concave portion that is in contact with the inner peripheral surface.

The elastic bush (A) of the above embodiment is
The suspension is mounted by press-fitting the outer cylinder (2) into the mounting hole of the arm member (6) in the suspension. For example, in the torsion beam suspension shown in FIG.
The elastic bush (A) of the present invention is attached to the bush (61) at the front end of the trailing arm (60) extending in the vehicle front-rear direction, and the bush shaft in the vehicle width direction is connected to the inner cylinder (1).
Insert and use.

At this time, in the elastic bush (A), the flange (8) is located on the vehicle inner side, and the recess (5) extends in the direction in which the arm member (6) such as the trailing arm extends. The arm member (6) is attached to the arm member (6) so as to be located opposite to a certain vehicle front-rear direction, and to be located opposite the vehicle up-down direction.

In this use, the original spring characteristics can be maintained in the axial direction and the direction perpendicular to the axis, and
By the swing of the arm member (6), for example, the swing of the trailing arm in a substantially horizontal plane, the torsion force transmitted from the arm member (6) can be effectively absorbed by the undercut (4), and the rubber elastic body ( The distortion due to compression and tension in the flange portion (31) of 3) is reduced, and the durability is improved. At the same time, a spring portion (5) provided opposite to the vehicle in the vertical direction reduces a vertical spring constant, softly absorbs vertical vibration of the suspension arm member (6), and improves riding comfort.

FIG. 4 shows a second embodiment of the elastic bush (A) of the present invention, and is a sectional view at the same angle as FIG. In FIG. 4, the same components as those of the first embodiment are denoted by the same reference numerals.

In this embodiment, the two bushes (10) (10) having the same structure as the first embodiment are connected to the mounting holes of the arm member (6) on the side without the flange (8). Are press-fitted so that they face each other.

That is, the two bushes (10) (1
0) is provided at one end thereof with a flange portion (31) of a rubber elastic body (3) sandwiched between flanges (11) and (21) of the inner and outer cylinders (1) and (2); A bore portion (4) similar to that of the above-described embodiment is provided at a portion of the flange portion (31) facing the extending direction of the arm member (6). Further, the body portion (32) of the rubber elastic body (3) is provided with a burring portion (5) at a portion facing the vehicle up-down direction.

The bush (10) (10)
Are fixedly fitted into the mounting hole of the arm member (6) from both sides by press-fitting so that the ends having no flange (8) face each other.

For this reason, the length of the outer cylinder (2) is slightly shorter than １ ／ of the width of the arm member (6) so that the flange (21) can be press-fitted to a position where it comes into contact with the arm end face. Good to keep. The bush (10)
The undercut (4) and the undercut (5) of (10) are provided in parallel on the same line.

In the case of the elastic bush (A), the combination of the two bushes (10) and (10) results in the presence of a flange having a recess at both ends, so that the spring characteristics in use as the elastic bush, In other words, the spring characteristics in the axial direction and the direction perpendicular to the axis, and the spring characteristics against the twisting force can be favorably maintained, and the durability can be further improved. Adjustment of characteristics becomes possible.

FIG. 5 shows a third embodiment of the elastic bush (A) of the present invention, and is a sectional view at the same angle as FIG. In FIG. 5 as well, components that are the same as in the first embodiment are given the same reference numerals.

In this embodiment, as in the second embodiment, 2
When the two bushes are attached to the arm member (6) so as to face each other, particularly, the end of the bush (10a) opposite to the flange (11) of the inner cylinder (1) is extended,
The inner cylinder (1) of the other bush (10b) is press-fitted and connected to the outer periphery of the extension (1a) of the inner cylinder (1) of the one bush.

That is, the inner cylinder (1) is made of a rubber elastic body (3).
The extended portion (1a) of the inner cylinder (1) of the longer bush (10a) is inserted into the mounting hole of the arm member (6), and the outer cylinder (2) is pressed into the mounting hole. The outer cylinder (2) of the bush (10b) is press-fitted from the opening opposite to the mounting hole, and the inner cylinder (1) is press-fitted into the extension (1a) of the inner cylinder. In addition, the point that the undercut portion (4) is provided in the extending direction of the arm member (6) and the point that the undercut portion (5) is disposed in the vehicle vertical direction are the same as in the above-described embodiment.

In the case of this embodiment, both bushes (10a)
The combination connection of (10b) is facilitated, and it is easy to apply pre-compression to the rubber elastic body (3) for the purpose of reducing tensile strain by using the press-fitting of the inner cylinder (1). It is possible to adjust the pre-compression by the press-in amount, in particular. As shown in the figure, the bush (10b)
The inner cylinder (1) is press-fitted over the entire length,
The coaxiality of the bush (10a) and the bush (10b) can be easily obtained.

[0043]

As described above, the elastic bush of the present invention is provided with the undercut so as to effectively absorb the twisting force caused by the swing of the arm member in relation to the extending direction of the arm member. In addition, the spring characteristics in the axial direction and the direction perpendicular to the axial direction are favorably maintained, and furthermore, the effect of reducing distortion due to compression and tension due to the twisting force from the arm member is excellent, and durability can be improved.

Particularly, in the suspension arm extending in the vehicle front-rear direction, by providing a curving portion at a position in the vehicle vertical direction together with the above-mentioned curving portion, the durability is improved by absorbing the twisting force, and the vertical vibration is reduced. Therefore, it is possible to improve the ride comfort.

Further, by adopting a structure in which the two bushes are opposed to each other, the degree of freedom in setting the spring characteristics is high, and in particular, the pre-compression can be easily applied to the rubber elastic body.

[Brief description of the drawings]

FIG. 1 is a sectional view taken along line XX of FIG. 2 showing an elastic bush according to a first embodiment of the present invention.

FIG. 2 is a front view of the elastic bush.

FIG. 3 is an enlarged cross-sectional explanatory view of a undercut portion.

FIG. 4 is a sectional view of the same portion as FIG. 1 showing an elastic bush according to a second embodiment of the present invention.

FIG. 5 is a sectional view of the same portion as FIG. 1 showing an elastic bush of a third embodiment of the present invention.

FIG. 6 is a perspective view showing an example of a torsion beam type suspension.

FIG. 7 is a longitudinal sectional view showing an example of a conventional elastic bush.

FIG. 8 is a longitudinal sectional view showing another example of a conventional elastic bush.

[Explanation of symbols]

 (A) Elastic bush (1) Inner cylinder (2) Outer cylinder (3) Rubber elastic body (4) Hole (5) Sink (6) Arm member (8) Flange (10) (10a) (10b) Bush (11) Flange of inner cylinder (21) Flange of outer cylinder (31) Flange part of rubber elastic body (60) Trailing arm

Continuation of front page (72) Inventor Hiroshi Ohno 1-17-18 Edobori, Nishi-ku, Osaka-shi, Osaka Toyo Tire & Rubber Co., Ltd.

Claims (4)

[Claims] 1. An elastic bush having a rubber elastic body interposed between an inner cylinder and an outer cylinder and having a flange provided at one end thereof and attached to an arm member, wherein a flange portion of the rubber elastic body is provided. A resilient bush, wherein a hollow portion is provided at a portion facing the extending direction of the arm member. 2. The elastic bush according to claim 1, wherein the arm member is a suspension arm, and a curving portion is provided at a position in a vehicle vertical direction of a main body of the rubber elastic body. 3. An elastic bush, wherein the two bushes according to claim 1 or 2 are attached to an arm member with their ends having no flange facing each other. 4. The elastic bush according to claim 3, wherein the inner cylinder of one bush is press-fitted to and connected to the inner cylinder of the other bush.