JPH0689809B2 - Liquid-sealed elastic bush - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (a) Field of Industrial Application The present invention relates to a liquid-sealed elastic bush suitable for use in engine mounts of automobiles.

(B) Conventional technology An elastic bush in which an elastic body such as rubber is filled between an outer cylinder and an inner cylinder is known, and further, this elastic bush is used for supporting a heavy object such as an automobile engine. Therefore, in some cases, the inner cylinder is eccentric with respect to the outer cylinder in advance in a direction opposite to the load direction so that the inner cylinder comes to a regular position (substantially concentric position) when a load is applied.

By the way, recently, this eccentric type elastic bush, especially,
An attempt was made to develop a so-called liquid-sealing type elastic bush in which a liquid chamber communicating with an orifice was defined in an elastic body and the liquid was enclosed in the liquid chamber for the purpose of exhibiting damping properties in the low-frequency vibration range. (For example, JP-A-61-31736).

(C) Problems to be Solved by the Invention In general, in a liquid-sealed elastic bush, it was considered that the desired damping property could not be obtained if the spring constant was lowered to improve the vibration damping property.

That is, lowering the spring constant means inevitably reducing the wall thickness of the elastic chamber wall or the like that constitutes the liquid chamber. It was absorbed by deformation, etc., and as a result, liquid movement did not occur and it was thought that the damping effect could not be expected.

Therefore, it is not enough to simply reduce the spring constant by thinning the chamber walls, etc., as seen in the preceding example,
It was necessary to take special measures to improve the damping property.

However, as a result of research conducted by the present inventors, the behavior of not only the compression side but also the expansion side liquid chamber is an important factor in the liquid movement, and as long as the volume on the expansion side increases during vibration, it slightly increases. They have found that even if the chamber wall on the compression side is thin, there is no problem in liquid transfer due to the sufficient suction effect.

(D) Means for Solving the Problems In the present invention, therefore, the inner cylinder is arranged parallel to the outer cylinder and eccentrically arranged, and the elastic chamber wall is provided between the outer cylinder and the inner cylinder. In the liquid-sealed elastic bush in which a plurality of liquid chambers are defined on the offset side and the offset side of the eccentricity, and the liquid chambers are communicated by an orifice, the biased side of the elastic chamber wall is provided. The basic constitution is that a part of the above is formed thinly in the direction of the liquid chamber, and a part of the deviation side is also thinly formed. The chamber wall and a part on the side of deviation are curved in the direction of the liquid chamber. Inside the liquid chamber, a cup-shaped elastic interior with a bottomed cup that receives the orifice cylinder that forms the orifice by the recessed hole provided on the upper surface It is an optional additional structure such as the installation of members. It

(E) Action As described above, the spring constant of both the biasing side liquid chamber and the biasing side liquid chamber is reduced due to the thin wall of the elastic chamber wall. As well as
Due to this, the volume change during vibration is promoted, and in particular,
The suction effect is fully exerted as the volume on the expansion side increases,
The liquid transfer is performed without any shortage, and the damping property in the low frequency vibration range can be satisfied. In addition, when the inner and outer cylinders are displaced to their proper positions during mounting and support, the elastic chamber wall is thin on the part on the biased side and at the same time has a curved shape toward the liquid chamber. Since the internal stress is not generated as much as possible, the spring constant is lowered and the durability is positively affected.

(F) Embodiment Hereinafter, an embodiment of the present invention will be described with reference to the drawings.
1 and 2 are longitudinal sectional views of a liquid-sealed elastic bush according to the present invention, FIG. 3 is a lateral sectional view, FIG. 4 and FIG. 5 are side views, front views, and FIG. Longitudinal sectional view of the embodiment, FIG. 7,
FIG. 8 is a perspective view of the interior member.

This liquid-sealing elastic bush is arranged such that the inner cylinder 2 is parallel to and eccentric to the outer cylinder 1 made of a metallic material, and between the outer cylinder 1 and the inner cylinder 2. An elastic chamber wall 3 made of an elastic material such as rubber is provided to define a plurality of liquid chambers 4 on the eccentric side and the eccentric side, and the liquid chambers 4 are communicated by an orifice 5. It is a thing.

That is, in the axial direction of the outer cylinder 1, the partition wall portion 3a of the elastic chamber wall 3 is provided between the outer cylinder 1 and the inner cylinder 2 at a substantially horizontal position (see FIG. 3). In the direction perpendicular to the core, side wall portions 3b are stretched with a constant space therebetween (see FIG. 1 etc.), and these members define the liquid chamber 4 in the vertical direction. It should be noted that the inside of these liquid chambers 4 is filled with a predetermined liquid 6.

On the other hand, the orifice 5 is formed by forming a small hole 5a at the center in the axial direction.
A cylindrical orifice cylinder 7 (having a linear orifice portion 5a) is externally fitted to the inner cylinder 2 in a state of being projected into each liquid chamber 4, and a groove 5b communicating with the small hole 5a ( The circular orifice portion 5b is formed) along the outer circumference of the inner cylinder 2 (see FIG. 3). A sleeve 8 is attached to the periphery of the outer cylinder 1, and the sleeve 8 is usually inserted and fixed in the housing on the mounting side.

By the way, the eccentricity of the inner cylinder 2 with respect to the outer cylinder 1 in advance (the amount of eccentricity e) means that when the support is supported and a predetermined load is applied, these start for the first time at the normal position (substantially concentric position). This is to make the width of the core even in both the upper and lower parts (see FIG. 2).

Next, according to the present invention, the elastic chamber wall 3 (the outer cylinder 1
The side wall portion 3b of the inner cylinder 2 and the inner tube 2 is formed thinly so as to be bent inward toward the liquid chamber 4, and the side wall of the offset side (also the longer side) is formed. The portion 3b also has a thin structure (see FIG. 1).

In this way, a part of the elastic chamber wall 3 on the biased side is made thin so as to be bent inward of the liquid chamber 4 so that the biased elasticity of the biased side is obtained when the load is placed in a normal position. This is because the chamber wall 3 stretches well so that stress in the tensile direction is not left and the spring constant is lowered. Further, a part of the elastic chamber wall 3 on the offset side is also made thin in order to reduce the spring constant of this part and realize a soft spring as the entire bush. In this case, it may be considered that the elastic chamber wall 3 is also curved inward of the liquid chamber 4.

FIG. 6 shows an example in which a bottomed cup-shaped elastic interior material 10 for receiving the orifice cylinder 7 in the upper surface of the orifice cylinder 7 is installed in the liquid chamber 4, which is provided. The reason is as follows.

That is, at the time of compression during vibration, the volume of the gap between the orifice cylinder 7 and the recessed hole 9 decreases, and the liquid 6 tries to be discharged to the outside, but since it has resistance, it passes through the orifice 5. It becomes easy to move to the upper liquid chamber 4. In addition, the tip of the orifice cylinder 7 hits the bottom of the recessed hole 9 to act as a kind of stopper when it is largely displaced, and also acts as a stopper when the elastic chamber wall 3 bends inward at this time. Can be expected. From these things, the liquid chamber 4 to be installed
Can be considered not only in the liquid chamber 4 on the deviation side but also in the liquid chamber 4 on the deviation side, and the recessed hole 9 thereof has a so-called hole shape (see FIG. 7) or a simple groove. A shape (see FIG. 8) is also conceivable.

(G) Effect of the Invention As described above, the present invention is as described above, that is,
The elastic chamber wall 3 that defines the liquid chamber 4 in the bush has a thin portion that is bent toward the inner side of the liquid chamber 4, and a portion of the compression chamber that is also thin. By doing so, the volume change of both the expansion side and the compression side liquid chambers 3 during vibration becomes easy, the so-called pumping function of suction and discharge works effectively, and the movement of the liquid 6 becomes easy. is there.

Therefore, the damping property in the low-frequency vibration range is excellent, and since the elastic chamber wall 3 is made thin, the spring constant of the entire bush is also reduced, so that the vibration-proof property in the high-frequency vibration range is also high.

In addition, by bending the elastic chamber wall 3 on the eccentric side inward, internal stress when a predetermined load is applied is reduced, and the elastic chamber walls 3 on both the eccentric side and the eccentric side are formed in this way. By making it very thin, stress concentration is less likely to occur and it is also excellent in durability.

In addition, if the elastic interior member 10 is installed in the liquid chamber 4, the movement of the liquid 6 is further promoted to improve the damping property, and it also serves as a stopper at the time of large displacement. Also serves as a protector when bending.

[Brief description of drawings]

1 and 2 are a longitudinal cross-sectional view of a liquid-sealed elastic bush according to the present invention, FIG. 3 is a cross-sectional view, FIG. 4 and FIG. 5 are side views, front views, and FIG. Longitudinal sectional view of the embodiment, FIG. 7,
FIG. 8 is a perspective view of the interior member. (Code) 1 ... Outer cylinder 2 ... Inner cylinder 3 ... Elastic chamber wall 4 ... Liquid chamber 5 ... Orifice 7 ... Orifice cylinder 9 ... Recessed hole 10 ... Elastic interior member

Claims (3)

[Claims] 1. An inner cylinder (2) is parallel to an outer cylinder (1),
In addition, they are arranged eccentrically, and an elastic chamber wall (3) is installed between the outer cylinder (1) and the inner cylinder (2) to provide a plurality of liquid chambers on the eccentric side and the eccentric side, respectively. In addition to defining 4),
In a liquid-sealing type elastic bush in which these liquid chambers (4) communicate with each other through an orifice (5), a part of the elastic chamber wall (3) on the biased side is bent inward in the liquid chamber (4). A liquid-sealed elastic bush characterized in that it has a thin shape of the above-mentioned shape and a part of the deviation side is also thin. 2. The liquid-sealing type elastic according to claim 1, wherein a part of the elastic chamber wall (3) on the offset side is bent inward of the liquid chamber (4). bush. 3. An orifice (5) in the liquid chamber (4).
Recessed cup-shaped elastic interior member (10) for receiving the orifice cylinder (7) that forms the groove in the recessed hole (9) provided on the upper surface.
The liquid-sealed elastic bush according to claim 1 or 2, characterized in that: