JPS62274128A - Liquid seal type elastic bush - Google Patents

Abstract

PURPOSE:To reduce a spring constant under making liquid movement by means of sufficient suction effect possible, by forming a part of an elastic chamber wall for a thin configuration which is curved in the directions of the inside of liquid chambers. CONSTITUTION:An inner cylinder 2 is disposed eccentrically against an outer cylinder 1, and an elastic chamber wall 3 is mounted therebetween so as to define plural liquid chambers 4. Then, respective liquid chambers 4 are communicated mutually by an orifice 5. A part of the eccentric side of the elastic chamber wall 3 is formed for a thin configuration which is curved in the directions of the inside of the liquid chambers 4, and a part of its compression side is also formed thinly. Thereby, volume change of the liquid chambers 4 both of the expansion side and the compression side in case of vibration becomes easy, liquid movement becomes easy, and a spring constant can be reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION 3. Detailed Description of the Invention (a) Field of Industrial Application The present invention particularly relates to a liquid-sealed elastic bushing suitable for use in automobile engine mounts and the like.

(b) Conventional technology Elastic bushings in which an elastic body such as rubber is filled between an outer cylinder and an inner cylinder are known, and these elastic bushings are also used to support heavy objects such as automobile engines. In order to do this, some types of cylinders have an inner cylinder eccentrically offset from the outer cylinder in advance in a direction opposite to the load direction, so that when a load is applied, the inner cylinder is in a normal position (approximately concentric position).

By the way, recently, this eccentric type elastic bushing, in particular,
For the purpose of exhibiting damping properties in the low frequency vibration range, two stages of liquid chambers connected through orifices were provided in one elastic body, and a liquid was sealed in these chambers. Attempts have been made to develop a so-called liquid seal type elastic bushing (for example, Japanese Patent Application Laid-open No. 31736/1983).

(c) In general, the problem that the invention seeks to solve, ′/! i. In sealed elastic bushings, it has been thought that if the vibration damping properties are increased by lowering the spring constant, the desired damping properties cannot be obtained.

This is because lowering the spring constant necessarily reduces the thickness of the elastic chamber walls that make up the liquid chamber, and in this way, changes in the volume of the liquid chamber due to vibrations can be reduced. This is because it was thought that the liquid would be absorbed by deformation, etc., and as a result, no liquid movement would occur and no damping effect could be expected.

Therefore, it is not enough to simply lower the spring constant by thinning the chamber walls, etc.; as seen in the previous examples mentioned above,
Special measures had to be taken to improve damping performance.

However, as a result of research conducted by these inventors, the behavior of the liquid chamber on the expansion side as well as on the compression side is an important factor in liquid movement, and during vibration, as long as the volume on the expansion side increases, the Even if the chamber wall on the compression side is thin.

They discovered that the suction effect was sufficient and there were no problems with liquid movement.

(d) Means for Solving the Problems Therefore, the present invention has been proposed by arranging the inner cylinder parallel to the outer cylinder and eccentrically, and installing an elastic chamber wall between the outer cylinder and the inner cylinder. In a liquid-sealing elastic bushing, in which a plurality of liquid chambers are defined on the eccentric side and the uneven part side of the eccentricity, respectively, and the liquid chambers are communicated with each other through an orifice, The basic configuration is that a part of the side is formed thin in a shape curved toward the inside of the liquid chamber, and a part of the uneven part side is also formed thin.

Furthermore, in this configuration, 8% of elastic chamber walls! A part of the i side is curved in the direction of the liquid chamber, and an elastic interior member in the shape of a cup with a bottom is installed in the liquid chamber to receive the orifice tube that forms the orifice in a recessed hole provided on the top surface. This is an optional additional configuration.

(e) As a result of the above effects, the overall spring constant of both the liquid chamber on the biased side and the liquid chamber on the biased side decreases due to the thin wall thickness of the elastic chamber, resulting in a reduction in the spring constant in the medium and high frequency vibration ranges. Along with improving vibrational properties,
Due to this, the volume change during vibration is also promoted, and in particular,
The suction effect due to the increase in volume on the expansion side is fully demonstrated,
The liquid movement is sufficient and the damping performance in the low frequency vibration range is also satisfactory. In addition, a part of the elastic chamber wall on the biased side is thin and at the same time has a curved shape in the direction of the liquid chamber, so that the inner and outer cylinders are displaced to their normal positions during installation and support. When this happens, internal stress is minimized, which has a positive effect on lowering the spring constant and improving durability.

(F) Examples Examples of the present invention will be described below with reference to the drawings.
1 and 2 are navy blue cross-sectional views of a liquid-sealed elastic bushing according to the present invention, FIG. 3 is a cross-sectional view, FIGS. 4 and 5 are a side view and a front view, and FIG. The reduced sectional view of the embodiment, FIGS. 7 and 8 are perspective views of the interior member.

This liquid seal type elastic bushing has an inner cylinder 2 arranged parallel to and eccentrically with respect to an outer cylinder 1 made of a metal material, etc., 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 installed to define a plurality of liquid chambers 4 on the eccentric side and the eccentric side, respectively, and these liquid chambers 4 are communicated with each other by an orifice 5. It is something that

That is, in the axial direction of the outer cylinder 1, the partition part 3a of the elastic chamber P43 is provided in a substantially horizontal position between the outer cylinder 1 and the inner cylinder 2 (see FIG. 3), and the axial In the direction perpendicular to the core,
The side wall portions 3b are stretched at regular intervals (see FIG. 1, etc.), and these members define the liquid chamber 4 in the vertical direction. Note that the interior of these liquid chambers 4 is filled with a predetermined liquid 6.

On the other hand, the orifice 5 is formed with a small hole 5a centered in the axial direction.
A cylindrical orifice tube 7 having a straight orifice portion 5a formed therein is inserted into each liquid chamber 4 and fitted onto the inner tube 2.

A groove 5b (circular orifice portion 5b) communicating with this small hole 5a
) is formed along the outer periphery of the inner cylinder 2 (see FIG. 3). A jacket tube 8 is attached around the outer cylinder 1, and the jacket tube 8 is usually installed and fixed by being inserted into a housing on the side.

By the way, the reason why the inner cylinder 2 is made eccentric with respect to the outer cylinder 1 in advance (eccentricity amount e) is that when a support is supported and a predetermined load is applied, the inner cylinder 2 is placed in its normal position (approximately concentric position). This is to make the amplitude equal to both the upper and lower sides (see Fig. 2).

Next, the present invention focuses on the biased side of one or more elastic chamber walls 3 (outer cylinder 1
The side wall portion 3b on the ionization side (also refers to the longer side) is configured to have a thin wall curved inward in the liquid chamber 4. The portion 3b is similarly thin (see FIG. 1).

The reason why the part of the biasing side of the second elastic chamber wall 3 is formed into a thin wall with a shape curved toward the inside of the liquid chamber 4 is that when a load is applied and the part is brought to the normal position, the biasing (Jll) This is to allow the elastic chamber wall 3 to expand well so that no stress remains in the tensile direction, and to lower the spring constant.

Furthermore, the reason why a part of the elastic chamber wall 3 on the 5-separation side is similarly made thin is to lower the spring constant of this part and realize a soft spring as a whole of the bushing. In this case, it is conceivable that the elastic chamber wall 3 is also curved inwardly into the liquid chamber 4.

The one shown in FIG. 6 has an orifice W in the liquid chamber 4.
This is an example in which a cuff-shaped elastic interior material 10 with a bottom is installed to receive the I7 in a recessed hole 9 formed on the upper surface thereof, and the reason for providing this is as follows.

That is, during compression during vibration, the gap volume between the orifice tube 7 and the recessed hole 9 decreases, and the liquid 6 tries to drain out to the outside, but since there is resistance to this, the liquid 6 does not pass through the orifice 5. This is because it becomes easier to move to the upper liquid chamber 4. Also, when there is a large displacement, the orifice tube 7
This is because it can be expected that the tip of the elastic chamber wall 3 will hit the bottom of this recess and act as a kind of stopper, and that it will also act as a stopper when the elastic chamber wall 3 bends inward at this time. In addition, from these reasons, the liquid chamber 4 to be installed is
Not only the liquid chamber 4 on the ionization side but also the liquid chamber 4 on the biasing side can be considered, and the recessed hole 9 may be in the shape of a hole (see Fig. 7) or simply in the shape of a groove. (See Figure 8) can also be considered.

(g) Effects of the invention Since this invention is as described above, that is,
A part of the biased side of the elastic chamber wall 3 that defines the liquid chamber 4 in the bush is made thin in a shape that is curved inward to the liquid chamber 4, and a part of the compression side is also thin. By doing so,
Expansion side during vibration.

The volume change of the liquid chambers 3 on both compression sides becomes easy, and the so-called pump action of suction and discharge works effectively.
This makes it easier for the liquid 6 to move.

Therefore, it has excellent damping performance in the low frequency vibration range, and since the spring constant of the bushing metal body is also reduced by making the 5 elastic chamber walls 3 thinner, the vibration isolation property in the high frequency vibration range is also high.

In addition, by bending the elastic chamber wall 3 on the uneven side inward, the internal stress when a predetermined load is applied is reduced, and the elastic chamber wall 3 on both the uneven side and the This is why I made it thin like this.

Stress concentration is less likely to occur, and the durability is also excellent.

In addition, if the above-mentioned elastic interior member 10 is installed in the liquid chamber 4, it will further promote the movement of the liquid 6 and improve the damping performance, and it will also act as a stopper in the event of a large displacement.
It also serves as a protector when the elastic chamber wall 3 is bent.

[Brief explanation of the drawing]

1 and 2 are longitudinal cross-sectional views of a liquid-sealed elastic bushing according to the present invention; FIG. 3 is a cross-sectional view; and FIG. 4 is a cross-sectional view. FIG. 5 is a side view and a front view, FIG. 6 is a longitudinal sectional view of another embodiment, and FIGS. 7 and 8 are perspective views of interior members. (Symbol) 1. Outer tube 2. Inner tube 3. Elastic chamber nitrogen 4. Liquid chamber 5. Orifice 7. Orifice tube 9. Recessed hole 10. Elastic interior member agent Patent attorney Itano Yoshio Figure 4 Figure 5 b Figure 7 Insert parts

Claims (1)

[Claims] [1] The inner cylinder (2) is arranged parallel to and eccentrically with respect to the outer cylinder (1), and between the outer cylinder (1) and the inner cylinder (2). An elastic chamber wall (3) is installed to define a plurality of liquid chambers (4) on the eccentric side and the eccentric side, respectively, and these liquid chambers (4) are communicated with each other by an orifice (5). In the liquid seal type elastic bushing, a part of the biased side of the elastic chamber wall (3) is formed into a thin shape curved inwardly of the liquid chamber (4), and a part of the biased side A liquid-sealed elastic bushing characterized by having a similar thin wall structure. [2] The liquid seal according to claim [1], characterized in that a part of the elastic chamber wall (3) on the deflection side is curved inward of the liquid chamber (4). Type elastic bushing. [3] In the liquid chamber (4), the orifice tube (7) forming the orifice (5) is inserted into the recessed hole (
9) A liquid-sealing type elastic bushing according to claim 1 or 2, characterized in that an elastic interior member (10) in the shape of a bottomed cup is installed to be received by the container.