JP2004316798A - Vibration isolator - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a vibration isolator comprising an outer cylinder, an inner cylinder and a rubber elastic member connecting both the cylinders to each other, in which the deformation stroke of a stopper rubber is enlarged so that the dynamic spring constant is prevented from being raised as much as possible. <P>SOLUTION: The vibration isolator is provided with the outer cylinder, the inner cylinder and the rubber elastic member between both the cylinders, connecting the cylinders to each other. Two clearances are defined between the outer cylinder and the inner cylinder by the rubber elastic member. The inner cylinder and the outer cylinder are attached to a vibration generating source and a skeleton. The vibration isolator has the stopper rubber extending from the outer cylinder toward the inner cylinder in at least one of the clearances, with a gap a interposed between the top end of the stopper rubber and the inner cylinder. The outer cylinder is provided with a recessed portion for a base portion of the stopper rubber, and the base portion is received in the recessed portion. The outer cylinder is denoted by 1; the recessed portion is denoted by 1a; the inner cylinder is denoted by 2; the rubber elastic member is denoted by 3; the stopper rubber is denoted by 4; the base portion of the stopper rubber is denoted by 4b; the gap between the top end of the stopper rubber and the inner cylinder is denoted by a; a height of the stopper rubber is denoted by b; and a distance between the outer cylinder and the inner cylinder is denoted by c. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a vibration isolator mainly used for an engine mount and a torque rod.
[0002]
[Prior art]
Hereinafter, the present invention will be described by taking an engine mount as an example. As a conventional vibration damping device of this type, a vibration damping device described in Patent Literature 1 is known, which includes an outer cylinder 31 and an inner cylinder as shown in FIG. The rubber elastic body 33 is provided between the rubber elastic body 33 and two clearances A and B penetrating in the axial direction on both sides of the inner cylinder 32, and the radial elastic body 33 has a substantially V-shaped cross-sectional shape in the radial direction. Is known. Normally, the outer cylinder 31 is fixed to the engine and the inner cylinder 32 is fixed to the vehicle body.
[0003]
[Patent Document 1] FIG. 4 of JP-A-6-74275
[0004]
An improved version of this type has a clearance A provided with a stopper rubber as shown in FIG. In the vibration isolator having such a structure, the clearance A is a displacement amount. However, the stopper rubber 34 is provided to add a dynamic characteristic to vibration, and the inner cylinder 32 is caused to collide with the stopper rubber 34. Vibration damping force will be provided.
[0005]
However, when an expected load is input, the stopper rubber 34 between the inner cylinder 32 and the outer cylinder 31 is crushed, resulting in a very high spring constant. Further, if the phenomenon that the stopper rubber 34 is repeatedly crushed frequently occurs, the aging of the stopper rubber 34 progresses, and the intended vibration damping effect is reduced.
[0006]
[Problems to be solved by the invention]
In a conventional vibration isolator, a stopper rubber 34 is provided in the clearance A, and the vibration damping function (low dynamic spring constant) is effectively exerted by colliding the stopper rubber 34 with the inner cylinder 32. However, it is desired that the stopper rubber 34 be over-compressed to suppress an increase in a dynamic spring constant such as vibration caused by excessive deformation of the rubber. The present invention has been made to solve the above-mentioned problem, and provides a vibration damping device in which the deformation stroke of the stopper rubber 34 is increased and the dynamic spring constant is not increased as much as possible.
[0007]
[Means for solving the problem]
The gist of the present invention is to provide an outer cylinder, an inner cylinder fitted with the outer cylinder, and a rubber elastic body connecting the outer cylinder and the inner cylinder, thereby forming two clearances between the outer cylinder and the inner cylinder, and forming the inner cylinder and the outer cylinder. A vibration isolator comprising a cylinder attached to a vibration source and a frame, wherein at least one of the clearances has a stopper-rubber while forming a gap a at a top portion from the outer cylinder side toward the inner cylinder side, In addition, a recess is formed in the outer cylinder with respect to the base of the stopper rubber, and the base is accommodated in the recess.
[0008]
Usually, the stopper-rubber base in the depression is shaped so that its periphery does not normally contact the depression.
[0009]
The rubber elastic body is formed in a single letter or a substantially V-shaped cross section in the radial direction, but the latter shape is often adopted, and the inner cylinder is buried in the closed leg portion. In general, a stopper is provided with a space a at the top of the clearance on the side from the outer cylinder side toward the inner cylinder side.
[0010]
BEST MODE FOR CARRYING OUT THE INVENTION
The present invention employs the above-described configuration. In response to a normal, predetermined load (vibration) input, the collision between the cylinder and the opposed cylindrical body is repeated, whereby the deformation of the stopper rubber is promoted. As a result, the dynamic spring characteristics of the vibration isolator are improved. However, when an unexpected load is input, the stopper rubber receives the input properly, the spring constant becomes extremely high, and the function as a vibration isolator tends to be lost.
[0011]
Now, since the strain rate of the rubber and the dynamic spring constant have a linear function relationship, in order to keep the dynamic spring constant low, a volume of rubber (stopper rubber) to be deformed is required. In the case of a vibration isolator having a structure in which the inner cylinder and the outer cylinder are combined, the volume of the stopper-rubber can be limited by the maximum displacement of the inner cylinder and the outer cylinder and the required clearance between the inner cylinder and the stopper-rubber. More specifically, if the volume of the stopper rubber is small, the dynamic spring constant increases due to contact with the inner cylinder after the maximum displacement, but the value of the dynamic spring constant is determined by the amount of deformation of the stopper rubber volume. Will be.
[0012]
According to the present invention, there is provided an anti-vibration device having the above-mentioned structure, in which a stopper rubber volume is secured in order to obtain a low dynamic spring constant. That is, by forming the base of the stopper rubber into a part of the outer cylinder, a free length (deformation stroke) against the deformation of the stopper rubber is secured, and the dynamic force under a large load is secured. Thus, the spring constant can be reduced.
[0013]
It goes without saying that the stopper rubber can be provided in both of the formed clearances, and the depressions can be provided not only on one side but also on both sides of the outer cylinder.
[0014]
【Example】
Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings. FIG. 3 shows an example of an engine mount which is an example of a vibration isolator. An inner cylinder 2 is inserted into an outer cylinder 1 and a rubber elastic body 3 having a substantially V shape is provided between the inner cylinder 2 and the inner cylinder. 2 is supported. Further, clearances A and B are provided between the outer cylinder 1 and the inner cylinder 2 by the rubber elastic body 3.
[0015]
At the clearance A on the open leg side of the rubber elastic body 3, the outer cylinder 1 is provided with a substantially Fuji-shaped stopper rubber 4 toward the inner cylinder 2, and a gap is provided between the top 4 a and the inner cylinder 2. a is formed. The gap a is determined in consideration of the magnitude of the expected load, the dynamic characteristics of the stopper rubber 4, and the like.
[0016]
The base portion 4b of the stopper rubber 4 is fixed to the outer cylinder 1. The outer cylinder 1 has a bulging portion formed outside and a depression 1a formed therein. The part 4b is stored. The stopper rubber 4 is formed so as not to be in contact with the periphery of the depression 1a in a normal state, and the height b (deformation stroke) of the stopper rubber 4 is, as shown in FIG. It is larger than the normal clearance c with the cylinder 2. The two-dot chain line indicates the inner surface of the ordinary outer cylinder 1 having no bulging portion.
[0017]
Therefore, when the relative displacement between the outer cylinder 1 and the inner cylinder 2 is smaller than a, vibrations and the like are absorbed by the characteristics of the rubber elastic body 3 itself. When the displacement is greater than a and less than or equal to c, the top 4a of the stopper rubber 4 and the surface of the inner cylinder 2 come into contact with each other and crush the stopper rubber 4, so that the desired dynamic spring is designed. Properties are brought. However, even when a large load such that the displacement reaches c is input, the rubber stopper is not overcompressed because the base portion 4b of the stopper rubber 4 is accommodated in the recess 1a of the outer cylinder 1. The deformation stroke can be maintained, and even in this case, the dynamic spring constant does not become unnecessarily large.
[0018]
FIG. 4 shows an example of a torque rod as another example of the anti-vibration device. The reference numerals and the behavior of each part are the same as those in the above-described example. 4b, a built-up portion 1b is formed inside the outer cylinder, and a recess 1a 'having substantially the same effect as the recess 1a of the previous example is formed therebetween. 4b fits.
[0019]
【The invention's effect】
As described above, according to the present invention, the stopper has a more excellent vibration damping device by incorporating the dynamic characteristics based on the compression deformation of the rubber into the vibration damping device. The deformation of the stopper rubber can be made large by devising the fixing part of the stopper rubber, and it can be used as a vibration isolator by controlling the displacement between the vibration source and the frame. Is an improvement in performance.
[Brief description of the drawings]
FIG. 1 is a diagram showing a conventional vibration isolator.
FIG. 2 is a diagram showing another example of a conventional vibration isolator.
FIG. 3 is a diagram showing a vibration isolator of the present invention.
FIG. 4 is a diagram showing another example of the vibration damping device of the present invention.
[Explanation of symbols]
1 ‥ outer cylinder,
1a, 1a '‥ depression,
1b ‥ overlay,
2 ‥ inner cylinder,
3 ‥ rubber elastic body,
4 ‥ stopper rubber
4a ‥ stopper-top of rubber,
4b {stopper-base of rubber,
A, B ‥ clearance,
a ‥ stopper-clearance between the top of the rubber and the inner cylinder,
b ‥ stopper-rubber height,
c ‥ The distance between the outer cylinder and the inner cylinder.

Claims (4)

An outer cylinder, an inner cylinder fitted to the outer cylinder, and a rubber elastic body connecting the two are provided therebetween, thereby forming two clearances between the outer cylinder and the inner cylinder. What is claimed is: 1. A vibration damping device attached to a skeleton, comprising: at least one of said clearances having a stopper rubber while forming a gap a at a top portion from an outer cylinder side toward an inner cylinder side; A vibration isolator, wherein a depression is formed in the outer cylinder with respect to the base, and the base is accommodated in the depression. 2. The vibration isolator according to claim 1, wherein the stopper rubber base in the depression is shaped such that its periphery does not normally contact the depression. 3. The vibration isolator according to claim 1, wherein the rubber elastic body has a substantially V-shaped cross section in a radial direction, and has an inner cylinder in a closed leg portion thereof. 4. The protection according to claim 1, further comprising a stopper rubber formed in the clearance on the open leg side of the rubber elastic body formed in a substantially V-shape to form a space a at the top from the outer cylinder side toward the inner cylinder side. Shaker.

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