JPH04125335A - Vibration isolator - Google Patents

Abstract

PURPOSE:To damp vibration in a wide range of by expanding and shrinking a main liquid chamber partition at the time when pressure of said chamber is increased, expanding and shrinking the first auxiliary liquid chamber partition at the time when pressure of said chamber is increased, and expanding and shrinking the second auxiliary liquid chamber partition at the time when pressure of said chamber is increased. CONSTITUTION:When vibration of large amplitude in low frequency is transmitted to a supporter 24, a thin diaphragm 48 is elastically deformed to enlarge and shrink the second auxiliary liquid chamber 50, and therefore, the fluid in a main liquid chamber 36 flows from the second orifice 68 into the second auxiliary liquid chamber 50. The vibration is absorbed by its passing resistance and further by liquid column resonance. The second orifice 68 having a long flowing route comes in a state of being blocked by vibration to block passing of fluid in a high frequency vibration. On the other hand, the second rubber film 42 which is thinner than the first rubber film 34 is elastically deformed, and the first auxiliary liquid chamber 36 is expanded and shrunk. Therefore, the fluid in the main liquid chamber 36 flows from the first orifice 56 into the first auxiliary liquid chamber 44 to lower a dynamic spring and absorb vibration by its passing resistance and further by the liquid column resonance. The vibration is also absorbed likewise in the vibration of a small amplitude in a high frequency.

Description

[Detailed Description of the Invention] The present invention relates to a vibration damping device which is provided between a vibration generating part and a vibration receiving part of a vehicle or general industrial machine, etc., and which absorbs vibrations from the vibration generating part. Regarding equipment.

[Background Art] In automobiles, an engine mount vibration isolating device is used between the engine and the vehicle body to absorb engine vibrations.

As shown in FIG. 8, a liquid chamber 102 filled with liquid is formed inside the vibration isolator 100. This liquid chamber 102 is connected to a main liquid chamber 106 and a sub-liquid chamber 10 by an orifice member 104 having a substantially hat-shaped cross section and arranged inside the liquid chamber 102.
It is divided into 8.

The orifice member 1 is located inside the orifice member 104.
An orifice 110 is formed whose longitudinal direction runs along the 040 circumferential direction, and an opening 110A is formed in the orifice member 104 corresponding to one end of the orifice 110 in the longitudinal direction. Further, an opening 110B is formed in the orifice member 104 corresponding to the other longitudinal end of the orifice 110. As a result, the orifice 110 communicates the main liquid chamber 106 and the auxiliary liquid chamber 108.

In this type of vibration isolator 100, when the vibration has a low frequency and a large amplitude of about 1082, vibration occurs due to passage resistance and liquid column resonance when the liquid in the main liquid chamber 106 passes through the orifice 110 and flows into the auxiliary liquid chamber 108. is attenuated.

However, it is difficult to effectively damp relatively high frequency vibrations and high frequency small amplitude vibrations.

[Problems to be Solved by the Invention] In consideration of the above facts, the present invention aims to provide a vibration isolating device that can effectively damp a wide range of vibrations ranging from low frequency, large amplitude vibrations to high frequency, small amplitude vibrations. It is.

[Means for Solving the Problems] The present invention provides a first member connected to one of a vibration generating section and a vibration receiving section, a second member connected to the other, and a first member and a second member connected to the other. A main liquid chamber that is provided between the main liquid chamber and the main liquid chamber and expands and contracts in response to vibration, and a main liquid chamber that forms part of the partition wall of this main liquid chamber and elastically deforms to expand and contract the main liquid chamber when the pressure of the main liquid chamber increases. a first sub-liquid chamber that communicates with the main liquid chamber via a first restriction passage; a second expansion/contraction means that expands and contracts the first sub-liquid chamber by elastically deforming when pressure increases; a second sub-liquid chamber communicating with the main liquid chamber via a second restriction passage; and a second sub-liquid chamber. a third expansion/contraction means that constitutes a part of the partition wall of the chamber and expands and contracts the second secondary liquid chamber by elastically deforming when the pressure of the second secondary liquid chamber rises, the third expansion/contraction means forming a part of the partition wall of the chamber, and reducing passage resistance of the first restriction passage. is made smaller than the passage resistance of the second restriction passage, and the rigidity of the first expansion/contraction means to the third partition means is sequentially lowered.

[Operation] In the present invention, the first expanding/contracting means and the second expanding/contracting means do not elastically deform during low-frequency, large-amplitude vibrations, so the main liquid chamber and the first sub-liquid chamber do not expand/contract.

As a result, the liquid in the main liquid chamber does not pass through the first restriction passage.

On the other hand, since the third expansion/contraction means constituting the second sub-liquid chamber has the lowest rigidity, it is elastically deformed by the low-frequency vibration, so that the second
Liquid flows from the main liquid chamber through the restriction passage to the second sub-liquid chamber through the second restriction passage.

At this time, vibrations can be absorbed by the passage resistance of the liquid and the liquid column resonance occurring in the second restricted passage.

When the frequency is relatively high, the second restriction passage becomes clogged, so the liquid in the main liquid chamber passes through the first restriction passage. Moreover, since the second expanding/contracting means has lower rigidity than the first expanding/contracting means, the second expanding/contracting means elastically deforms and the second sub-liquid chamber expands/contracts.

As a result, the liquid in the main liquid chamber does not pass through the first restriction passage.

At this time, liquid column resonance occurs in the first restricted passage and vibrations can be absorbed.

When the frequency is high frequency and small amplitude vibration, the first restriction passage and the second restriction passage become clogged, so the liquid in the main liquid chamber does not pass through the first restriction passage and the second restriction passage. Therefore, elastic deformation of the first expanding/contracting means causes liquid column resonance and vibrations can be absorbed.

[First Embodiment] FIGS. 1 and 2 show a first embodiment of a vibration isolator according to the present invention.

As shown in FIG. 1, a mounting bolt 14 is protruded from the center of the bottom plate 12 of the vibration isolator 10, and is adapted to be fixed to the body of an automobile (not shown), for example.

The periphery of the bottom plate 12 is a cylindrical vertical wall portion 12A bent at right angles.
A flange portion 12B having a raised portion 12C bent at right angles is continuously formed at the upper end portion of this standing wall portion 12A. A flange portion 16A of the outer cylinder 16, which is fixed to the bottom plate 12, is caulked to the flange portion 12B.

The side opposite to the flange portion 16A of the cylindrical portion 16C of the outer cylinder 16 forms an expanded portion 16B whose inner diameter is gradually enlarged, and the outer periphery of the vibration absorbing rubber 22 is vulcanized and bonded thereto. The outer circumferential portion of the support base 24 is vulcanized and bonded to the inner circumferential portion of the vibration absorbing rubber 22 . This support base 24 is a mounting part for an engine (not shown), and a mounting bolt 26 is protruded so that the engine can be fixed.

Further, an extension portion 22A of the vibration absorbing rubber 22 is vulcanized and bonded to the inner peripheral surfaces of the cylindrical portion 16C and the flange portion 16A of the outer cylinder 16.

An orifice member 2 is provided inside the outer cylinder 16 and the bottom plate 12.
6 is placed.

As shown in FIG. 2, the orifice member 26 includes a substantially cylindrical inner cylinder 28 and an outer cylinder 30 that is fitted onto the inner cylinder 28. A circular hole 32 is formed in the inner cylindrical body 28 in the axial direction, and this circular hole 32 is closed by a thick first rubber membrane 34 . As a result, as shown in FIG.
6 and the first rubber film 34 form a main liquid chamber 36. The main liquid chamber 36 is filled with liquid such as water and oil.

A rubber membrane support 40 having a hat-shaped cross section is disposed on the bottom plate 12 side of the inner cylindrical body 28. This rubber membrane support 40
A circular hole 40B is formed in the top plate portion 40A, and this circular hole 4
A second rubber film 42 is vulcanized and bonded so as to close 0B. Since the second rubber film 42 is formed thinner than the first rubber film 34, its rigidity is also weaker. The second rubber film 42 is fitted into the circular hole 32 of the inner cylindrical body 28 and is vulcanized and bonded, so that the second rubber membrane 42 closes the circular hole 32. As a result, the inner cylindrical body 28, the first rubber membrane 34 and the second
A first sub-liquid chamber 44 is formed by the rubber film 42 .

This first sub-liquid chamber 44 also contains water, as in the main liquid chamber 36.
It is filled with liquid such as oil.

A second comb membrane 42 is provided on the bottom plate 12 side of the rubber membrane support 40.
The diaphragm 48 is made of a thinner rubber membrane than the diaphragm 48.
is installed. Therefore, the first rubber film 34, the second rubber film 42, and the diaphragm 48 are made of rubber in descending order of hardness.

The outer peripheral portion 48A of the diaphragm 48 is connected to the outer cylindrical body 30.
The flange portion 30A of the rubber membrane support 40, the flange portion 4 of the rubber membrane support 40
It is clamped and fixed together with 0C by the flange portion 12B of the bottom plate 12 and the flange portion 16A of the outer cylinder 16. As a result, a second sub-liquid chamber 50 is formed by the rubber membrane support 40, the second rubber membrane 42, and the diaphragm 48.

This second sub-liquid chamber 50 also contains water, as in the main liquid chamber 36.
It is filled with liquid such as oil.

Further, an air chamber 52 is formed between the diaphragm 48 and the bottom plate 12, and is communicated with the outside as necessary.

As shown in FIGS. 1 and 2, a substantially C-shaped groove 54 whose longitudinal direction runs along the circumferential direction is formed on the outer circumferential surface of the inner cylindrical body 28. As shown in FIGS. This groove 54 is formed in the cylindrical portion 30 of the outer cylindrical body 30.
It is closed by the inner peripheral surface of B. An opening 54A is formed in the inner cylindrical body 28 corresponding to one longitudinal end of the groove 54 and communicates with the main liquid chamber 36. Further, an opening 54B is formed in the inner cylindrical body 28 corresponding to the other longitudinal end of the groove 54, and communicates with the first sub-liquid chamber 44. This allows groove 5
4 is a first orifice 56 that communicates the main liquid chamber 36 and the first sub-liquid chamber 44 .

Furthermore, grooves 60 and 62 are formed in the outer circumferential surface of the cylindrical portion 30B of the outer cylinder 30, the longitudinal direction of which extends along the circumferential direction of the cylindrical portion 30B. The longitudinal directions of these grooves 60, 62 are parallel to each other. As shown in FIG. 1, these grooves 60, 62 are closed by the extension 22A of the vibration absorbing rubber 22.

As shown in FIG. 2, the groove 60 is prevented from going around the cylindrical shape 130B by the raised surface 64. Also,
The groove 62 is also prevented from going around the cylindrical portion 30B by the raised surface 66.

An opening 60A is formed in the cylindrical portion 30B corresponding to one longitudinal end of the groove 60 and communicates with the main liquid chamber 36.

Further, the cylindrical portion 30B corresponding to the other longitudinal end of the groove 60
An opening 60B is formed in and communicates with one longitudinal end of the groove 62. An opening 62B is formed in the cylindrical portion 30B corresponding to the other end of the groove 62 in the longitudinal direction. This opening 62B corresponds to the opening 40D formed in the rubber membrane support 40.

Thereby, the groove 62 is communicated with the second sub-liquid chamber 50. Therefore, the main liquid chamber 36 and the second sub-liquid chamber 50 are communicated via the groove 60.62, and the groove 60.62 is connected to the second orifice 6.
It is said to be 8. Therefore, the second orifice 62 goes around the cylindrical portion 30B approximately twice, and has greater passage resistance than the first orifice 56.

Next, the operation of the first embodiment will be explained.

The bottom plate 12 is fixed to the vehicle body via mounting bolts 14 (not shown), and the engine mounted on the support base 24 is fixed using mounting bolts 26.

When low-frequency, large-amplitude vibrations with a frequency of, for example, around 10 Hz are transmitted to the support base 24, the thin-walled diaphragm 48 is elastically deformed, causing the second sub-liquid chamber 50 to expand and contract, and the main liquid chamber 36 to expand and contract. The liquid passes through the second orifice 68 and flows into the second sub-liquid chamber 50.

As a result, vibrations are absorbed by the passage resistance when the liquid passes through the second orifice 68. Further, liquid column resonance occurs between the main liquid chamber 36 and the second auxiliary liquid chamber 50 via the second orifice 68, and the vibration is also absorbed by the liquid column resonance.

When vibrations with a relatively high frequency, for example around 30 Hz, are transmitted to the support base 24, the second
The vibration causes the orifice 68 to become clogged, and liquid is prevented from passing through the second orifice 68.

On the other hand, since the second rubber film 42, which is thinner than the first rubber film 34, is elastically deformed and the first sub-liquid chamber 36 expands and contracts, the liquid in the main liquid chamber 36 passes through the first orifice 56 and The liquid flows into the first sub-liquid chamber 44.

As a result, vibrations are absorbed by the passage resistance when the liquid passes through the first orifice 56. Furthermore, liquid column resonance occurs between the main liquid chamber 36 and the first auxiliary liquid chamber 44 via the first orifice 56, lowering the dynamic spring and absorbing the vibration. Furthermore, noise and vibration occurring around 30 Hz can also be reduced.

When high-frequency, small-amplitude vibrations having a frequency of, for example, around 250 Hz are transmitted to the support base 24, the first orifice 56 and the second orifice 68 become clogged due to the vibration, and the liquid flows through the first orifice 56 and the second orifice 68. be prevented from passing through. For this reason, the main liquid chamber 36
The liquid does not flow into the first sub-liquid chamber 44 and the second sub-liquid chamber 50. As a result, the first rubber film 34 is elastically deformed, the main liquid chamber 36 expands and contracts, liquid column resonance occurs within the liquid chamber 36, and the vibration is absorbed. Furthermore, noise and vibration occurring around 250 Hz can also be reduced.

[Second Embodiment] FIG. 3 shows a second embodiment of the vibration isolator according to the present invention. Note that the same components as those in the first embodiment are given the same reference numerals, and the explanation thereof will be omitted.

In this embodiment, the movable portion 7 of the movable plate 70 is located in the main liquid chamber 36.
2 is suspended so that it can vibrate.

The movable portion 72 is made of an elastic material such as rubber and is formed into a disk shape. One end of the boss portion 74 of the movable plate 70 is fitted into the movable portion 72, and the other end is fitted into the support base 24.

The other configurations are the same as in the first embodiment.

Next, the operation of the second embodiment will be explained.

When high-frequency vibration with a frequency of around 300 Hz is transmitted to the support base 24 and this vibration is transmitted to the main liquid chamber 3B, the first
The high frequency vibrations cause the orifice 56 and the second orifice 68 to become clogged, and the liquid is prevented from passing through the first orifice 56 and the second orifice 68. Therefore, the movable portion 72 of the movable plate 70 in the main liquid chamber 36 vibrates in the axial direction of the vibration isolator 21O.

As a result, the liquid in the main liquid chamber 36 moves with the movable portion 72 as a boundary, as shown by arrow A in FIG.

As a result, liquid column resonance occurs around the movable portion 72, making it possible to lower the movable spring and damping vibrations.

Therefore, in this embodiment, it is possible to attenuate even high frequency vibrations having a frequency of around 300 Hz, and has the effect of being able to attenuate vibrations in a wider range of frequencies than the vibration isolator 10 of the first embodiment.

Other operations are similar to those of the first embodiment.

The movable spring can also be adjusted up and down by changing the diameter of the movable portion 70 of the movable plate 70.

[Third Embodiment] FIGS. 4 and 5 show a third embodiment of the vibration isolating device according to the present invention. Note that the same components as those in the first embodiment are given the same reference numerals, and the explanation thereof will be omitted.

The shape of the inner cylinder 328 of the vibration isolator 310 of this embodiment is different from the shape of the inner cylinder 28 of the vibration isolator 10 of the first embodiment (see FIG. 1). That is, the side closer to the support base 24 than the first rubber film 34 vulcanized and bonded to the inner cylinder 328 (upper side in FIG. 4)
The cylindrical portion 328A of the inner cylindrical body 328 is extended. A top plate portion 328B is formed on the support base 24 side of the inner cylinder 328. A circular hole 330 having a smaller diameter than the circular hole 32 of the inner cylindrical body 328 is formed in this top plate portion 328B.
30 is an orifice 332 (17).

The other configurations are the same as in the first embodiment.

Next, the operation of the third embodiment will be explained.

When high frequency vibration with a frequency of around 300 Hz is transmitted to the support base 24 and this vibration is transmitted to the main liquid chamber 36, the first
The high frequency vibrations cause the orifice 56 and the second orifice 68 to become clogged, and the liquid is prevented from passing through the first orifice 56 and the second orifice 68. Therefore, the liquid in the main liquid chamber 36 passes through the orifice 332, causing liquid column resonance.

As a result, it becomes possible to lower the moving spring, and vibrations can be damped. Therefore, like the second embodiment, this embodiment can also damp vibrations around a frequency of 300 Hz.
This has the effect of damping vibrations in a wider range of frequencies.

Other operations are similar to those of the first embodiment.

Note that by changing the diameter of the circular hole 330, it is also possible to adjust the movable spring up and down.

[Fourth Embodiment] FIGS. 6 and 7 show the fourth embodiment of the vibration isolating device 10 according to the present invention.
An example is shown.

The vibration isolator 410 of this embodiment is applied to a strut mount of a vehicle.

As shown in FIG. 6, a flange portion 414 is fixed to one axial end of the cylindrical inner tube 412. As shown in FIG. The inner cylinder 4
A support tube 416 whose flange portion 414 side is expanded is fitted onto the outside of the support tube 12 . This support cylinder 416 is the same as the inner cylinder 412.
It is welded into one piece. An outer cylinder 420 is disposed coaxially with the inner cylinder 412. This outer cylinder 420 includes a first outer cylinder part 422 formed to protrude in a direction perpendicular to the axial direction and a second outer cylinder part 424 having a cylindrical shape.
It is composed of. A portion of the second outer cylinder portion 424 opposite to the first outer cylinder portion 422 is caulked and fixed to a cylindrical portion 426 .

A vibration absorbing rubber 432 is stretched between the support cylinder 416 and the first outer cylinder part 422 and is vulcanized and bonded thereto. This vibration absorbing rubber 432 is formed with an extension part 432A, and this extension part 432A is connected to the forward rotation first outer cylinder part 422 and the second outer cylinder part 42.
It is vulcanized and bonded to the inner peripheral surface and outer peripheral surface of No. 4, respectively.

The orifice member 4 is located in the axially intermediate portion of the inner cylinder 412.
34 is fitted externally. This orifice member 434 is fixedly or slidably attached to the front inner cylinder 412.

As shown in FIG. 7, the orifice member 434
An outer cylinder 438 is provided coaxially with 36. An inner cylinder 436 and an outer cylinder 43 are provided between the inner cylinder 436 and the outer cylinder 438.
An intermediate cylinder 440 is disposed coaxially with the cylinder 8. This intermediate cylinder 440 is formed with a439 and has a U-shaped cross section. Further, the axial length of the intermediate cylinder 440 is the same as that of the inner cylinder 4.
36, it is formed shorter than the axial length of the outer cylinder 438.

A thick first rubber film 444 is provided on the flange portion 414 side of the inner cylinder 436 and the intermediate cylinder 440 and is vulcanized and bonded thereto. As a result, a main liquid chamber 436 is formed by the vibration absorbing rubber 432 and the orifice member 434.

A second rubber film 446, which is thinner than the first rubber film 444, is vulcanized and bonded to the inner cylinder 436 and the outer cylinder 438 on the opposite side from the flange portion 414. As a result, there are an inner cylinder 436 and an outer cylinder 43 inside the orifice member 434.
8. Intermediate cylinder 440, first rubber membrane 444 and second rubber membrane 4
46 forms a first sub-liquid chamber 448.

A diaphragm 450 is hooked between the cylindrical portion 426 and the inner cylinder 412 on the opposite side of the flange portion 414 of the orifice member 434 and is vulcanized and bonded thereto. As a result, a second sub-liquid chamber 452 is formed between the second rubber film 446 and the diaphragm 450. Therefore, in this embodiment, the first rubber film 444, the second rubber film 446, and the diaphragm 450 are made of rubber in descending order of hardness.

An intermediate cylinder 440 corresponding to one longitudinal end of the groove 439
An opening 440A is formed in the groove 439 to communicate with the first sub-liquid chamber 448, and an opening 440B is formed in the other longitudinal end of the groove 439 to communicate with the main liquid chamber 436. As a result, the groove 489 communicates with the main liquid chamber 436 and the first sub-liquid chamber 448, and serves as a first orifice 454.

Further, a groove 456 whose longitudinal direction extends along the circumferential direction is formed on the outer circumferential surface of the trust outer cylinder 438. This groove 456 is closed by the extension portion 432A of the vibration absorbing rubber 432. The cross-sectional area of the groove 456 is formed to be much smaller than the cross-sectional area of the groove 439, so that the passage resistance is large. Groove 45
An opening 45 is provided in the outer cylinder 438 corresponding to one end in the longitudinal direction of 6.
6A is formed and communicates with the main liquid chamber 436, and an opening 456B is formed in the outer cylinder 438 corresponding to the other longitudinal end of the groove 456 and communicates with the second sub-liquid chamber 452. As a result, the groove 456 communicates between the main liquid chamber 436 and the second sub-liquid chamber 452, and serves as a second orifice 458.

Next, the operation of the fourth embodiment will be explained.

The outer cylinder 420 is fixed to a vehicle body (not shown) via a bracket portion 422A, and a damper rond constituting a shock absorber (not shown) is inserted into the inner cylinder 412.

Low-frequency, large-amplitude vibrations with a frequency of around 10Hz occur in the inner cylinder 41.
2, the thin diaphragm 450 is elastically deformed, so that the second sub-liquid chamber expands and contracts. Therefore, the liquid in the main liquid chamber 436 passes through the second orifice 458 and flows into the second auxiliary liquid chamber 452 . As a result, the liquid
The vibration is absorbed by the resistance when passing through the orifice 458. Furthermore, liquid column resonance occurs between the main liquid chamber 436 and the second auxiliary liquid chamber 452 via the second orifice 458, and the vibration is absorbed.

Zhou/J! When vibrations with a relatively high frequency (i number around 70 Hz) are transmitted to the inner cylinder 412, the second orifice 458, which has a small cross-sectional area, becomes clogged due to the vibrations, and the liquid passes through the second orifice 458. be prevented from passing.

On the other hand, the second comb film 44 is thinner than the first rubber film 444.
Since G is elastically deformed, the first sub-liquid chamber 448 expands and contracts.

Therefore, the liquid in the main liquid chamber 436 flows through the first orifice 4.
54 and flows into the first sub-liquid chamber 448.

As a result, the liquid in the main liquid chamber 436 passes through the first orifice 454 and flows into the first sub-liquid chamber 448 . As a result, liquid column resonance occurs between the main liquid chamber 436 and the first sub-liquid chamber 448 via the first orifice 454, the dynamic spring is lowered, and the vibration is absorbed.

High-frequency, small-amplitude vibrations with a frequency of around 250H2 occur in the inner cylinder 4.
12, the first orifice 454 and second orifice 458 become clogged, and liquid is prevented from passing through the first orifice 454 and second orifice 458. Therefore, the liquid in the main liquid chamber 43B is transferred to the first sub-liquid chamber 448 and the second sub-liquid chamber 4.
52. As a result, the first rubber film 444 is elastically deformed, the main liquid chamber 436 expands and contracts, liquid column resonance occurs in the main liquid chamber 436, and the vibration is absorbed.

In addition, in the first to fourth embodiments, two sub-liquid chambers, a first sub-liquid chamber and a second sub-liquid chamber, and two orifices, a first orifice and a second orifice, were respectively formed. Three or more sub-liquid chambers and orifices may be formed. In this way, by increasing the number of sub-liquid chambers and orifices, it is possible to cause more liquid column resonance and further dampen vibrations.

Furthermore, although the first to fourth embodiments show vibration isolators applied to engine mounts and strut mounts, the device is not limited to this and may be applied to cab mounts, body mounts, etc. Of course.

[Effects of the Invention] As explained above, the vibration isolating device according to the present invention has an excellent effect of being able to reliably damp vibrations over a wide range from low frequency, large amplitude vibrations to high frequency, small amplitude vibrations.

[Brief explanation of the drawing]

1 and 2 show a first embodiment of the vibration isolator according to the present invention, in which FIG. 1 is a longitudinal sectional view, FIG. 2 is a perspective view of the entire orifice member partially cut away, and FIG. A vertical sectional view corresponding to FIG. 1 showing a second embodiment of the vibration isolator according to the invention, and FIGS. 4 and 5 show a third embodiment of the vibration isolator according to the invention,
FIG. 4 is a longitudinal sectional view, FIG. 5 is a partially cutaway overall perspective view of the orifice member, FIGS. 6 and 7 show a fourth embodiment of the vibration isolator according to the present invention, and FIG. 6 is a longitudinal sectional view. FIG. 7 is a partially cutaway overall perspective view of the orifice member, and FIG. 8 is a longitudinal sectional view of a conventional vibration isolator. 10... Vibration isolator, 12... Bottom plate (first member), 16... Outer tube (second member), 34... First rubber membrane (first expansion/contraction means), 36 ...
Main liquid chamber, 42... Second rubber membrane (second expansion/contraction means), 44...
First sub-liquid chamber, 48... diaphragm (third expansion/contraction means), 50...
・Second sub-liquid chamber, 56...first orifice (first restriction passage), 68・
...Second orifice (second restricted passage).

Claims (1)

[Claims] (1) The first one connected to either the vibration generating part or the vibration receiving part
a second member connected to the other member, a main liquid chamber provided between the first member and the second member that expands and contracts in response to vibration, and a part of a partition wall of the main liquid chamber. , and expands and contracts the main liquid chamber by elastically deforming when the pressure in the main liquid chamber increases.
a first sub-liquid chamber that communicates with the main liquid chamber via a first restriction passage; a second expansion/contraction means that expands and contracts the first sub-liquid chamber by elastically deforming when rising; a second sub-liquid chamber communicating with the main liquid chamber via a second restriction passage; and the second sub-liquid chamber. a third expansion/contraction means forming a part of the partition wall and elastically deforming to expand and contract the second auxiliary liquid chamber when the pressure of the second auxiliary liquid chamber increases, the third expansion/contraction means forming a part of the partition wall of the second auxiliary liquid chamber; A vibration isolating device characterized in that the passage resistance of the second restriction passage is lower than that of the second restriction passage, and the rigidity of the first expansion/contraction means to the third partition means is successively lowered.