JPS62220732A - Vibration isolator encapsulating liquid - Google Patents

Abstract

PURPOSE:To damp the vibration of loss factor frequency which is different from orifice to orifice effectively by providing diaphragm chambers dedicated for respective orifices. CONSTITUTION:The low frequency components in the vibration of a power unit are damped by means of the first and second diaphragm chambers 31, 32 while the high frequency components are damped by the function of a rubber member 24. In other word, the low frequency components are damped by the vibration to be produced when the working liquid in a liquid chamber 25 moved through the first and second orifices 34, 35 between the liquid chamber 25 and the first and second diaphragm chambers 31, 32 as the rubber member 24 deforms. Consequently, the vibration of loss factor frequency which is different from orifice to orifice can be damped.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application This invention relates to a liquid-filled vibration isolator, and relates to a liquid-filled vibration isolator that has a plurality of vibration damping regions by providing a plurality of separated orifices. Regarding the vibration body.

BACKGROUND OF THE INVENTION A conventional liquid-filled vibration isolator using this glaze is disclosed in, for example, Japanese Unexamined Patent Publication No. 58-72741C. However, in this liquid-filled vibration isolator, multiple orifices are provided in one common diaphragm chamber, so a loss factor occurs in the orifice on the side where the liquid passage resistance is large. Even if you try, the liquid will move easily through the orifice on the side where the resistance to liquid passage is small. Therefore, the loss factor peak value of the frequency band served by the orifice on the side with larger passing resistance is significantly smaller than the loss factor peak value of the frequency band served with the orifice on the side with smaller passing resistance (see Figure 3). As a result, the effect of providing a plurality of orifices is not fully demonstrated, and there is almost no difference from providing only one orifice.

By the way, the peak values of each loss factor generated by the plurality of orifices (2) are determined to be approximately the same size, that is, the loss factor characteristic is drawn by a curve that smoothly connects each peak value. It is known that the loss factor in the frequency band between peak values and in the vicinity of the peak value is also set large, so that the vibration damping region can be widened.

Therefore, the loss factor generation function of each orifice is fully demonstrated without being influenced by other orifices. Two liquid-filled vibration isolators have already been developed (%wI No. 1987-195210).

That is, as shown in FIG. 8, this liquid-filled vibration isolator 1 has an elastic body between the power unit side outside the figure and the vehicle body side (2) between the first frame body 2 and the second frame body 3 to be attached. A liquid chamber 5 is provided which is liquid-tightly surrounded by a rubber body 4. At the upper and lower ends of this liquid chamber 5, a first partition plate 6 and a first partition plate 6 integrally extended from the first frame 2 are provided. A second partition plate 7 is provided at the lower end of the second frame body 3, and the upper part of the first partition plate 6 is covered with a first diaphragm 8 in a liquid-tight manner.
1. The lower part of the second partition plate 7 is made liquid-tight by the second diaphragm 8 (
There are two types. The space between the first partition plate 6 and the first diaphragm 8 is defined as a first diaphragm chamber 10, and the space between the second partition plate 1 and the second diaphragm 9 is defined as a second diaphragm chamber 11. On the other hand, the first partition plate 6 (2) is a labyrinth-shaped first partition plate that communicates the liquid chamber 5 and the first diaphragm chamber 8.
An orifice 12 is formed in the second partition plate I, and a labyrinth-shaped second orifice 13 that communicates the liquid chamber 5 and the second diaphragm chamber 11 is also formed in the second partition plate I. Also, a first covering plate 14 extending above the first diaphragm 8
Peripheral edge portion +: The peripheral edge of the first frame body 2 is fixed by caulking, sandwiching the frame plate 8a of the first diaphragm 8.

On the other hand, the periphery of the second frame 3 is caulked and fixed to the periphery of the second cover plate 15 covering the lower part of the second diaphragm 9, sandwiching the periphery of the second partition plate 7 and the periphery of the second diaphragm B. There is.

The passage length of the first orifice 12 is formed relatively short to set a large peak frequency of the loss factor, and the passage length of the second orifice 13 is formed relatively long to increase the loss factor. The peak frequency is set low. Furthermore, the first diaphragm 8 is made thicker than the second diaphragm B to increase its rigidity, and its expansion elasticity is set to be higher than that of the second diaphragm 9. , one loss factor characteristic obtained by all orifices is a state in which approximately equal peak values are connected by a smooth curve, and a wide range C:
f2 is set so that a high loss factor value can be obtained throughout.

Problems to be Solved by the Invention However, in the above-mentioned Japanese Patent Application No. 60-195210, the first diaphragm chamber 1o and the second diaphragm chamber 11 are vertically separated with the liquid chamber 5 in between, as described above. The structure is complicated because they are arranged separately and independently. In addition, the manufacturing work becomes complicated and costs increase, as the first and second winter frames 2 and 3 must be separately caulked and fixed to the first and second winter use plates 14 and 15, respectively. There is Peng.

Furthermore, each of the above-mentioned conventional liquid-filled vibration isolators (-) has not been designed to suppress the dynamic spring constant against medium and high frequency vibrations such as engine vibrations and muffled noises. Vehicle body vibration cannot be sufficiently reduced.

Means for Solving the Problems This invention provides a method in which a liquid chamber surrounded by an elastic body communicates with each diaphragm chamber dedicated to each orifice through a plurality of orifices each having a different peak frequency of a loss factor,
and the diaphragm expansion elasticity of each diaphragm chamber,
The liquid-filled vibration isolator is configured such that the loss factor peak frequency of the corresponding orifice is set higher as the loss factor peak frequency is larger, and each of the diaphragm chambers is integrally formed with the predetermined diaphragm interposed therebetween. It is characterized in that the predetermined diaphragm separating the diaphragms is provided so as to be slightly movable in the axial direction of each diaphragm chamber.

According to the present invention (2) having the above configuration, by providing a diaphragm chamber dedicated to each orifice, vibrations having different loss factor frequencies for each orifice can be effectively damped through each orifice.

In addition, it has been confirmed by the applicant≦2 that the loss factor peak value exhibited by each orifice (-) is proportional to the magnitude of this peak frequency, and inversely proportional to the magnitude C of the diaphragm expansion elasticity of the diaphragm chamber. Therefore, by configuring the diaphragm expansion elasticity as described above, the heights of the loss factor peak values of each orifice can be made approximately equal.

Moreover, in the middle and high frequency vibration range f2 of the car body, the predetermined diaphragm that separates each diaphragm chamber slightly moves in the axial direction of the diaphragm chamber, which suppresses the dynamic spring constant and sufficiently suppresses vibration in the high frequency range. can be reduced to i
]. Furthermore, since each diaphragm chamber is integrally formed by polymerization, the structure is not only simplified, but also the production efficiency of the vibration isolator can be improved.

Example Hereinafter, embodiments of the present invention will be described in detail based on the drawings.

FIG. 1 shows a first embodiment of the present invention, and this liquid-filled vibration isolator 21 has a power unit side (not shown) and a vehicle body side (not shown).
It has a first support frame 22 and a second support frame 23 that are attached to the housing, and a rubber body 24 that is an elastic body is surrounded in a liquid-tight manner between the first and second support frames 22 and 23. A liquid chamber 25 is provided, and an air chamber 26 is also provided, which is airtightly separated from the liquid chamber 25 via a second diaphragm 30 having a large diameter disc shape. Further, at the bottom of the liquid chamber 25, a partition plate 27 with a bulge in the center is provided.
and a support plate 28 in the shape of a circular mound, a part of which is joined to the outer circumferential end C of the partition plate 27, are arranged at a predetermined distance from the second diaphragm 30.

Then, between the partition plate 21 and the second diaphragm 30, a disk-shaped first
A first diaphragm chamber 31 and a second diaphragm chamber 32 are formed vertically and integrally with each other via the diaphragm 29. In addition, the support plate 28 has an outer portion 2θa formed on the inner periphery of an annular support frame 33 made of synthetic resin.
It is supported by a loose fit that allows slight movement up and down (maximum movement of approximately 0.4 m). Furthermore, the first diaphragm chamber 31
The liquid chamber 25 (the two are in communication with each other through a short first orifice 34 inserted approximately in the center of the partition plate 27).
The diaphragm chamber 32 communicates with the liquid chamber 25 through an annular second orifice 35 formed by expanding a portion of the partition plate 27 that is joined to the support plate 28 to have a rectangular cross section. One end is formed in the partition plate 27, and the other end is formed in the support plate 28C: an opening 35a r 3 formed respectively.
5b. The first orifice 34 is formed short to set the peak frequency of the loss factor high, while the second orifice 35 is formed long in an annular shape to set the peak frequency of the loss factor small.

Furthermore, the thickness of the first diaphragm 29 is made larger than that of the second diaphragm 30 to increase rigidity.
Two branches are determined so that the expansion elasticity of the diaphragm 29 is higher than the expansion elasticity of the second diaphragm 30. This is determined based on the experimental results conducted by the inventors of the present invention, which showed that the peak frequency of the loss factor due to the orifice increases as the expansion elasticity of the diaphragm increases.

The second diaphragm 30 and the annular support frame 33 are connected to the outer peripheral edge 23a of the second support frame 23 and the rubber body 24.
The diaphragm chamber 3 is clamped between the outer peripheral edge 38a of the annular frame 36 that covers the outside of the diaphragm chamber 3 (the two sides are fixed together).In this way, each diaphragm chamber 3 is
1, 32, etc. can be formed together, improving manufacturing efficiency.

Therefore, according to this embodiment 1 and 2, the low frequency component of the power unit vibration is caused by the first . Second diaphragm 831,3
2, etc., the -blade high frequency component is sufficiently attenuated by the action of the rubber body 24, the first diaphragm 2B, the partition plate 27, etc. That is, the low frequency component is caused by the deformation of the rubber body 24 (as a result of the deformation of the rubber body 24, the working liquid (for example, water) in the liquid chamber 25 passes through the first and second orifices 34 and 35 to the liquid chamber 25 and the first and second C″- so that the vibration is damped by moving between the diaphragm chambers 31 and 32.
It has become. Further, the loss factor peak frequency of the first orifice 34 having a short length is set to a high frequency band in the low frequency range, and the loss factor peak frequency of the long second orifice 35 is set to a frequency band 1 which is low among the low frequencies. −
settings, effectively damping vibrations in each frequency band. In this embodiment, the liquid-filled vibration isolator 21 is used to support the power unit, and the allocation targets are 5 to 5.
207, the loss factor peak frequency ft on the low frequency side is set to 5 to 8 Hz, and the loss factor peak frequency f2 on the high frequency side is set to around 13 to 18 Hz. , fz
It is tuned to cover the frequency range of the engine shake with a loss factor characteristic of .

FIG. 2 shows the same components as those in FIG.
The experimental results of the vibration characteristics will be described based on the model diagram 1m of the liquid-filled vibration isolator 21 shown in J. In addition, in the figure, the photographing input direction spring of the rubber body 24, K+t/'
i Spring due to expansion elasticity of the rubber body 24, K! is the expansion elasticity Kd of the first diaphragm 29 and the spring, K is the spring due to the expansion elasticity Kd2 of the second diaphragm 30 and the nitrogen spring of the air chamber 2B, mfl and ml are the springs of the first diaphragm 29. The liquid mass in the second orifices 34 and 35, A1 is an equal cross-sectional area in the liquid chamber 25, A2. AM is number 1. Second diaphragm 2
9 and 30, S2 and Ss are the 1st and 2nd
Opening area of orifices 34 and 35, 12, 1s
is the first. The length of the second orifices 34 and 35 is shown.

The table below (- shows the expansion elasticity Kdl of the first diaphragm 2g and the second diaphragm 30 based on the above model,
These are the results of an experiment in which Kdz was changed by one so as to obtain the target loss factor characteristic.

Table 3 shows the loss factor characteristics when the six diaphragm expansion elasticities are changed, and the characteristic (1) in the figure is:
The expansion elasticity Kd of the first diaphragm 29 is 45Kt/m.
, the second diaphragm 30 is 2. OKp/ml: When set, in this case the loss factor peak value on the low frequency side (approximately 5 Hz area) is slightly lower, and on the high frequency side the loss factor peak value (approximately 12 Hz area) is compared. However, the curve is smooth compared to that of the above-mentioned Japanese Patent Application Publication No. 58-72741 (group C;
Loss factor (tafiδ) of the engine shake frequency range covered between the two peak values and near the two peak values
) values are set uniformly large. As a result, the engine shake frequency range is 1. 2nd orifice 34, 3
5 and 1st. The second diaphragm chambers 31 and 32 efficiently damp the signal.

Further, the characteristics (It) are that the expansion elasticity Kd+ of the first diaphragm 29 is 20 Ky/■, and the expansion elasticity Kd+ of the second diaphragm 30 is 20 Ky/■.
．． When set to OKp/1m, in this case, contrary to the above, the loss factor peak value on the low frequency side (approximately 5 Hz area)
is relatively high, and the loss factor peak value (approximately 12 Hz region) is slightly low on the high frequency side, but the curve is relatively smooth as in the previous case. Therefore, the loss factor (taI) on the high/low frequency side is different from the case of characteristic (1) above.
+) Although the values are different, the loss factor value in the engine shake frequency range covered between the two peak values and near the two peak values is uniformly large 0. In any of the above cases, the diameter of the first orifice is 3.5
The diameter of the second orifice is 4 mm, and the length is 150 mm.

On the other hand, in the middle and high frequency ranges, for example 30 to 250 Hz, it is 0.
In the case of an amplitude of 1■ or less, the entire first diaphragm chamber 31 including the first diaphragm 29 slightly moves up and down via the support plate 28, so that the dynamic spring constant is as shown by characteristic I in FIG. (It) is sufficiently suppressed up to about 150 Hz. As a result, together with the vibration absorbing effect of the rubber body 24, the vibrations of medium and high wave number components are effectively damped.

FIG. 5 shows a second embodiment of the present invention, in which the outer end 28a of the support plate 28 is fixed to the annular support frame 33 via an annular rubber member 40 so as to be movable up and down. Also,
The vertical movement range of the support plate 2B is the annular groove 33 of the annular support frame 33.
a Maximum limit is approximately 0.4 mC at the upper and lower edges. Therefore, in this embodiment, the same effects as in the first embodiment can be obtained, and the first diaphragm 29 can suppress the dynamic spring constant, thereby sufficiently damping medium and high frequency vibrations.

FIG. 6 shows a third embodiment of the present invention, in which the second orifice 35 is composed of an annular plate 50 and a support plate 28 that are separate from the partition plate 21, The outer end of the support plate 28 is overlapped with the outer end of the second diaphragm 30, and each outer peripheral edge 23 of the second support frame 23 and the annular frame 3B is
a, integral C: fixed between 38a. Also,
The flange-shaped outer end 27a of the partition plate 27 is connected to the annular plate 5.
0 and the inner end of the support plate 28, the support plate 28 is loosely fitted and supported in an annular groove 51 formed between the inner end of the support plate 28 so as to be able to move slightly up and down while the maximum movement is limited to 0.4 m.

Therefore, this embodiment also has a first effect on high frequency vibrations.
Since the entire first diaphragm chamber 31 including the diaphragm 29 moves slightly up and down, the movement spring constant is suppressed, and the middle and
High frequency vibrations can be sufficiently damped.

Figure 7 shows a fourth embodiment of the present invention, in which the outer end 27a of the partition plate 27 in the third embodiment is movable up and down on the support plate 2B via an annular rubber member BO.
The vertical movable range is limited to about 0.4 m+ at the upper and lower edges of the ring $61. Therefore, this embodiment also provides the same effects as the third embodiment.

In each of the above embodiments, the case where the frequency range of engine shake is mainly damped has been described, but it is also possible to damp other objects of vibration. It is also possible to apply the present invention to other vibration damping bodies, such as suspension bushings.

Effects of the Invention As is clear from the above explanation, in the liquid-filled vibration isolator of the present invention, each loss factor peak value can be set to a large value without being influenced by other orifices, and each orifice The resulting loss factor peak values can be made substantially equal. Therefore, a high loss factor value can be obtained over a wide range, and as a result, one vibration isolator can sufficiently reduce vehicle body vibration in the medium and high frequency ranges by combining with the vibration absorption function in the vibration damping region.

Further, in the present invention, since the plurality of diaphragm chambers are integrally formed via a predetermined diaphragm, the overall structure is extremely simple, and quality control is thereby facilitated. Furthermore, the number of manufacturing steps can be reduced (secondarily, manufacturing efficiency can be improved, and costs can be reduced).

[Brief explanation of drawings]

FIG. 1 is a sectional view showing a first embodiment of the invention, FIG. 2 is a model diagram of the invention, and FIG. 3 is a characteristic diagram showing aspects of various loss factors obtained through experiments based on this model. Fig. 4 is a comparison diagram showing the dynamic splash characteristics of an embodiment of the present invention and a conventional liquid-filled vibration isolator, and Fig.
6 is a sectional view showing a third embodiment of the invention, FIG. 7 is a sectional view showing a fourth embodiment of the invention, and FIG. 8 is a liquid-filled type according to the earlier application. It is a sectional view showing a vibration isolator. 21... Liquid-filled vibration isolator, 24... Rubber body (elastic body), 25... Liquid chamber, 27... Partition plate, 29...
・First diaphragm (predetermined diaphragm), 30...
Second diaphragm, 31...First diaphragm chamber, 3
2... Second diaphragm chamber, 34... First orifice, 35... Second orifice. 2 people outside Figure 8

Claims (1)

[Claims] (1) A liquid chamber surrounded by an elastic body communicates with each diaphragm chamber dedicated to the orifice through a plurality of orifices having different peak frequencies of loss factors, and the diaphragm expansion elasticity of each diaphragm chamber is set higher as the loss factor peak frequency of the corresponding orifice is larger, the diaphragm chambers are integrally formed via the predetermined diaphragm, and each diaphragm A liquid-filled vibration isolator characterized in that the predetermined diaphragm separating the chambers is provided so as to be slightly movable in the axial direction of each diaphragm chamber.