JPH03125045A - Liquid damping type vibration isolator - Google Patents

Abstract

PURPOSE:To improve durability without suffering excessive force or deformation on thin membranes by providing an air communicating line to introduce air to air chambers and discharge air from them, and mounting flexible thin membranes on a partition plate of rigid body. CONSTITUTION:Stopper plates to limit the movement range of a thin plate body 14 are formed with respective thin plate parts 11a, 11b having air communicating holes 12. Air chambers 17a, 17b capable of holding air are formed in the spaces surrounded with flexible thin membranes 16a,16b and a partition plate 7 and covering the air communicating holes 12. Charge and discharge of air against the air chambers 17a,17b are performed through a passage 15 to charge and discharge air and an air pipe 18. In this way, durability can be improved without generation of excessive force or deformation on the thin membranes.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to a liquid damping type vibration isolator that can be used in an automobile engine mount or the like to effectively absorb vibrations.

(Prior Art) As a vibration isolating device that supports an automobile engine so that its vibrations are not transmitted to the member side, two liquid chambers separated by a partition plate are provided inside an S-proof base made of rubber, and the partition plate A liquid damping type vibration isolator has conventionally been used in which an orifice having a required length and cross-sectional area is provided in the liquid chamber, and both liquid chambers are communicated through the orifice.

In recent years, the damping performance and other characteristics of this type of vibration isolator have been controlled externally, and as a means of control, it is not possible to change the elasticity of the vibration isolator itself. It has been proposed that an air chamber made of a flexible thin film is provided in the liquid chamber, and the characteristics can be changed by adjusting the pressure of the air chamber. There are some known ones.

What is shown in the above publication is that a thin film that can particularly run along the inner surface of the rubber elastic element is provided between the rubber elastic element that is the base and a separation wall that partitions two liquid chambers, and the thin film and the rubber elastic element are connected to each other. It has a structure that allows air to be supplied and discharged between the two.

(Problem to be Solved by the Invention) However, in the case of the above structure, when a load is applied to the upper support part during use and it is displaced in the vertical direction or load vibration occurs, the rubber elastic element normally Causes movement in the direction.

This may result in increased movement of the membrane provided along the inner surface of the rubber-elastic element, friction between the bearing or the rubber-elastic element and the membrane, or when air is evacuated and a negative pressure is applied. Moreover, it becomes difficult for the thin film to conform to the inner surface of the elastic element. As a result, the thin film itself becomes strained and damaged or weakened.
There is a problem that durability may be impaired.

By the way, the characteristics of automobile engine mounts are such that they must be able to block engine noise in the high frequency range, but must also be able to dampen engine vibrations in the low frequency range.In order to meet these required characteristics, liquid-filled mounts are required. Engine mounts were developed, but although they were able to improve the damping effect at low frequencies, the dynamic spring constant became high for high-frequency microvibrations, so they were not necessarily sufficient as a countermeasure against muffled noise.

For this purpose, a liquid-filled mount in which a movable plate with a small amount of clearance is incorporated into the partition plate has been proposed (
(Refer to Japanese Patent Application Laid-open No. 61-45130), at large amplitudes, the movement of the movable plate is restricted, producing fluid pressure fluctuations and a large damping effect is obtained, while at high frequency vibrations, the movement of the movable plate at minute amplitudes causes the hydraulic pressure to change. This has a certain effect in that fluctuations are alleviated and a low bounce constant can be obtained.

However, in order to sufficiently lower the dynamic spring constant in the high frequency range, a certain amount of clearance is required for the movable plate, so insufficient damping is inevitable, especially at medium and small amplitudes. In either case, it is not possible to obtain high damping performance for low frequency and small amplitude under low dynamic spring constant.
The reality is that there is a desire in the industry to realize something that can perform extremely fine control of characteristics depending on the driving state of the vehicle.

The present invention addresses this problem by supplying and discharging air from the outside to a liquid damping type vibration isolator, thereby making it possible to switch between maintaining high damping and maintaining a low dynamic spring constant, while maintaining a low dynamic spring constant. An object of the invention is to ensure a certain level of high damping characteristics even when the vibration is low, thereby exhibiting a vibration-proofing effect against a wide range of vibrations from low frequencies to high frequencies, and making it possible to provide a comfortable ride in a vehicle.

(Means for Solving the Problems) The present invention achieves the above object (as is clear from the drawings showing the embodiments, a vibration-proof base made of an elastic body such as rubber, a flexible membrane, etc. In a liquid damping type vibration isolator in which an inner chamber filled with liquid is divided into two liquid chambers by a partition plate, and the two liquid chambers are communicated with each other by an orifice provided on the outer periphery of the partition plate. The invention of claim 1 is characterized in that a flexible thin film is installed adjacent to both sides of the partition plate in a peripheral edge sealed state, excluding the opening of the orifice to each liquid chamber, and the thin film and the partition plate An air chamber capable of holding air is formed in an enclosed space, and the portion of the partition plate existing in the air chamber is sandwiched between a flexible thin film-like elastic body whose periphery is fixed, and this thin film-like elastic body. A stopper plate is formed of a plate having a plurality of air circulation holes arranged with narrow gaps on both sides, and air is introduced into and discharged from the air chamber at least on the vibration-isolating base side. It is characterized by variable vibration damping characteristics by providing an air circulation line.

Next, regarding the invention of claim 2, a flexible thin film is attached adjacent to both sides of the partition plate except for the opening to each liquid chamber of the orifice in a peripheral edge sealed state, and the thin film and the partition plate are connected to each other. In addition to forming an air chamber that can hold air in a space surrounded by, the part of the partition plate existing in the air chamber is attached to a thin plate body placed in a free state so as to be movable in the axial direction, and to both sides of this thin plate body. A stopper plate is formed of a plate having a narrow gap and a plurality of air circulation holes smaller in diameter than the arranged thin plate body, and air is introduced into and discharged from the air chamber, at least to the air chamber on the vibration isolating base side. The present invention is characterized in that the anti-vibration characteristics are made variable by providing an air circulation line that performs the following functions.

On the other hand, with respect to the invention of claim 3, a flexible thin film is installed adjacent to both sides of the partition plate in a peripheral edge sealed state, excluding the openings of the orifice to each liquid chamber, and the thin film and the partition plate An air chamber capable of holding air is formed in the space surrounded by the above-mentioned flexible thin film. A stopper plate having a plurality of liquid flow holes is disposed close to the vibration substrate side on the outer liquid chamber side, and air is introduced into the air chamber, at least into the air chamber on the vibration isolation substrate side. The vibration damping characteristics are made variable by providing an air circulation line for air flow and discharge.

Next, the invention according to claim 4 provides that the air circulation line includes a conduit for extracting negative pressure from the intake side of the engine supported by the liquid damping type vibration isolator, and a conduit for opening the air chamber to the atmosphere, or The invention specified in each of the preceding claims is constituted by a switching valve device to be connected.

In addition, the invention of claim 5 provides a structure in which air is discharged from the air chamber by the car stop signal No. 18 and the engine low rotation signal in response to idling vibration and cranking vibration when the car is stopped. It is specific to the invention described.

Furthermore, the invention of claim 6 specifies the configuration in which four air chambers are filled with air in response to a vehicle speed signal and an engine rotation signal in response to engine noise during steady running. According to the seventh aspect of the invention, air is discharged from the air chamber by a vehicle speed signal and a throttle position signal or a vehicle speed signal and a braking signal in response to an engine shaking phenomenon during acceleration, deceleration, or sudden braking. The structure is specified in the invention described in each of the preceding claims.

On the other hand, the invention according to claim 8 provides a solution to vibrations when traveling on a rough road.
The configuration in which air is discharged from the air chamber in response to the vehicle speed No. 13 and the road surface condition detection signal is specified in the invention described in each of the preceding claims.

(Function) According to the vibration isolator of the present invention, high damping performance in the low frequency range is desirable in order to suppress shaking of the power unit, for example, when idling, when suddenly accelerating/starting, and when driving on rough roads. In the vibration isolating device described in each section, the flexible thin film is brought into close contact with the partition plate by discharging air from the air chamber.

In this way, fluctuations in the liquid pressure on the vibration isolation base side due to load vibration between the two liquid chambers are absorbed by the air chamber of the partition plate, and are also transmitted to the other liquid chamber via the partition plate part. As a result, the liquid in the liquid chamber moves to the other liquid chamber through the orifice in response to the vibration of the vibration-isolating base, and this results in a large damping effect in combination with the inertial effect of the liquid column.

That is, the value of the loss spring constant becomes large.

On the other hand, during normal driving on good roads, there is vibration in the high frequency range.

Since noise isolation is required, air is introduced into the air chamber.

By doing this, fluctuations in the liquid pressure on the vibration-isolating base side due to the vibration of the supported object promote the movement of the thin film, and are transmitted to the other liquid chamber via the air chamber and the air circulation hole, causing the orifice to move. There is almost no movement of the liquid passing through the vibration damping base, there is no damping effect, there is no increase in the dynamic spring constant in the high frequency range, and the same effect is achieved as when the elasticity of the vibration isolating base is lowered.

Secondly, even when driving on good roads, engine shake (especially
Damping characteristics are often required in order to prevent engine mass resonance (resonance phenomenon of the engine mass), but in the device of the present invention, the stomp plate in each claim
The movement of the thin film-like elastic body, the thin plate body in a free state, or the flexible thin film is suppressed so that the movement of the liquid moves exclusively through the orifice to the other liquid chamber without affecting the other side through the partition plate part. , thus achieving the necessary allocation damping effect against large vibrations.

(Example) Hereinafter, an example of the present invention will be described based on the accompanying drawings.

FIG. 1 shows an embodiment according to claim 2 of the present invention, in which (1
) is a vibration-proof base made of an elastic material such as rubber, and the upper part has mounting bolts (
2a) is fixed, and the vibration-proof base (1) is attached to the tapered outer periphery of the lower hem depression.
An outer cylindrical metal fitting (3) extending downward in a cylindrical shape is fixed.

Note that the lower surface of the vibration isolating base fl) is formed into a concave curved shape suitable for forming a liquid chamber to be described later.

(4) is the mounting port for the vehicle body, frame, etc.) (4a
), the receiving metal fitting has a concave cross section, and has an open end (4b
), the lower end of the outer cylindrical metal fitting (3) on the side of the vibration isolating base (1) is fitted and connected by appropriate means such as caulking.

(5) is a membrane made of a flexible material provided so as to close the lower opening of the outer cylindrical fitting (3), and is an inner wall between the membrane (5) and the vibration-proofing base fl). A liquid (6) is sealed in the chamber.

(7) is the liquid (
The inner chamber filled with 6) is divided into two upper and lower liquid chambers (8a).
, (8b), and this partition plate (7) is fitted into the inner periphery of the outer cylindrical fitting (3), and the outer periphery edge is connected to the periphery of the membrane (5). It is held between the receiving metal fitting (4) and the outer cylindrical metal fitting (3).

Moreover, this keeps the liquid chambers (8a) and (8b) in a sealed state.

The partition plate (7) has one liquid chamber (8a) on its outer periphery.
The other liquid chamber (
8b) is provided with an orifice (9) opening therein;
This causes the liquid (6) to flow into both liquid chambers (8a) and (8b).
It is now possible to circulate between the two.

Inside the central part of this partition plate (7), there are thin plate parts (lla) and (ll
A circular cavity αψ is provided leaving the portion b), and each of the thin plate portions (lla) and (ll) on the upper surface side and lower surface side as described above
In b), a plurality of small-diameter air circulation holes (2) are provided in communication with the cavity Ql.

A thin plate body is housed in the cavity αω in a free state so as to be able to move vertically in the axial direction, so that the air circulation hole θ can be alternately closed on the upper surface side and the lower surface side. It is set up in

In addition, each thin plate portion (11a) having the air circulation hole 0
, (llb) forms a stopper plate for limiting the movement range of the thin plate body Q4).

On the other hand, (16a) and (16b) are thin films made of a material having appropriate elasticity and flexibility, such as rubber, and are thin films that are made of a material such as rubber that has appropriate elasticity and flexibility, and are thin films that cover the inside of the partition plate (7) except for the opening of the orifice (9). The thin films (16a), (16b) and the partition plate (7) cover the air circulation holes (2) and the space formed by the partition plate (7). Air chambers (17a) and (17b) capable of holding air are formed.

The air passes through the outer cylindrical fitting (3) and passes through the inside of the partition plate (7) to the cavity aφ, the air circulation hole (2), and the air chambers (17a) and (17b). The air chamber (17a), (1
It forms part of an air circulation line through which air can be introduced into or discharged from the air chamber (7b).
The volumes of 7a) and (17b) can be changed, and characteristics such as damping performance as a vibration isolator can be controlled.

Note that the thin film (16a) installed on the surface of the partition plate (7)
), (16b), when atmospheric pressure is applied to the air chambers (17a), (17b) surrounded by the air chambers (17a), (17b), the air chambers (17a), (16b) are substantially
It is preferable that the shape is designed to ensure the volume of 7b).

Moreover, the thin films (16a) and (16) of the partition plate (7)
The surface facing b) is the thin film (16a) as shown in the figure.
, (16b) is preferably formed into a concave shape that is approximately symmetrical to the inner surface shape when atmospheric pressure is applied. That is,
By forming the air chamber (17a) in this way,
When the air of (17b) is sucked and discharged, the thin film (1
6a) and (16b) can be closely attached to the surface of the partition plate (7) without causing any slack, and no strain will occur.

In the above-mentioned device, the air chambers (17a) and (17b) were formed by attaching flexible thin films (16a) and (16b) to both sides in contact with the partition plate (7). For example, when it is exposed to the atmosphere and air is introduced, the effect is the same as when the elasticity of the vibration-proof base (1) made of rubber or the like is lowered.

In other words, due to the presence of the air chambers (17a) and (17b), the movement of the liquid (6) due to the load vibration is caused by the thin film (16a)
, (16b) and air chamber (17a), (17b)
There is little movement of liquid (6) through the orifice (9), absorbed by the movement of the internal air.

In this case, when the vibration frequency is high and the amplitude is small, the thin plate body a0 vibrates at an intermediate position within the cavity α0) and is kept in a state where the air circulation hole (2) is not blocked, so that the air chamber (
17a) and (17b), and therefore there is almost no movement of the liquid (6) passing through the orifice (9), resulting in almost no damping effect.
There is no increase in dynamic spring constant.

On the other hand, when the vibration frequency is low and the amplitude is large, the thin plate body blocks the air circulation hole 0 depending on the degree of the amplitude, resulting in the liquid (5) passing through the orifice (9).
The amount of movement increases, thus producing a damping effect.

Furthermore, when the air in the air chambers (17a) and (17b) is sucked and discharged, the thin films (16a) and (16b) come into close contact with the partition plate (7) (as shown by the two-dot chain line in FIG. 1). As in the case without the air chambers (17a) and (17b), the liquid (6) in the liquid chamber (8a) or (8b) moves through the orifice (9) as the vibration isolating base (1) vibrates. The liquid column moves to the other liquid chamber (8a) or (8b), and together with the inertial effect of the liquid column, exhibits a large damping effect. That is, the value of the loss spring constant or damping coefficient increases.

Note that dynamic spring constants and damping coefficients are shown in Figures 6 and 7, and the broken lines, the dashed lines, and
Each is shown by a dashed line, and the case where air is discharged is shown by a solid line.

Therefore, by controlling the supply and discharge of air to and from the air chambers (17a) and (17b), it is possible to change characteristics such as damping performance.

Next, FIG. 2 shows an embodiment according to the invention of claim 1, and to explain the difference in structure from the example shown in FIG. 1, the cavity α provided in the partition plate (7) is The example shown in Figure 1 (former) has a short cylindrical shape, whereas the example shown in Figure 2 (latter) has a convex lens shape, and on the other hand, in the former, the thin plate Q4) can be moved in the axial direction into the cavity a0. In contrast, in the latter case, a flexible thin film-like elastic body such as a diaphragm that can vibrate is housed in a cavity θ0) with its surroundings fixed. ing.

It is natural that the inner part of the thin film elastic body 0314 vibrates up and down in response to air flow, and it is easy to understand that it can perform the same function as the former thin plate body 0314. Ru.

3 and 4 show an embodiment according to the invention of claim 3, and the explanation of the parts having the same structure as the example shown in FIG. 1 will be omitted, and the different structures will be explained below.

The partition body (7) is provided with one or more small diameter air circulation holes (a) in its center, penetrating between the upper and lower surfaces, and these air circulation holes (a!). Cover the air chamber (17a), (1
7b) on the top and bottom, respectively.
), (16b), at least its vibration-proofing base (a stopper plate so as to be close to the thin film (16a) on the 11 side on the outer liquid chamber (8a) side) (2ω is fixed to the partition plate (7) It is set up as follows.

The stopper plate (2Φ) is made of a rigid body, and has a convex curved shape that increases the distance from the surface of the partition plate (7) from the periphery to the center, and has small diameter liquid flow holes (21). A stopper plate having such a structure (2Φ functions as a stopper plate for regulating the movement stroke of the membrane (5) that moves up and down in response to vibration) is temporarily formed with a plurality of perforated holes. Therefore, it goes without saying that the vibration damping characteristics of the device of this example are the same as those of both of the above embodiments.

For the vibration isolators on each side described above, the air chamber (17a)
, (17b) The mechanism for controlling air introduction and discharge will be explained with reference to FIG.

(22) shows the main body of the vibration isolator, and the car body (23)
It is attached to and supports the engine (24).

The air pipes connected to the air chambers (17a) and (17b) are connected to the conduit (25) via a switching valve device (26), for example, a three-way switching valve.

The conduit (25) is provided with a vacuum tank (28) in the middle of the pipe, and the end of the pipe is branched and connected to the intake pipe (29) of the engine (24).

A control unit (27) is provided to perform the switching operation of the three-way switching valve (26), and the vehicle speed signal (27) from the vehicle speed sensor is sent to this control unit (27).
SL), engine speed signal from the engine tachometer (S
2) Throttle position signal from the throttle position sensor (S3), Road surface condition detection signal from the road surface sensor that checks the unevenness of the road surface (S4), Braking signal from the brake switch sent when the brake pedal is pressed ( S,) is input.

To explain the operation of the control 1 mechanism above, first, the vehicle communication signal (
S, ) of the stop signal and engine low rotation speed signal (S2
) is input, the three-way switching valve (26) is set to the solid line water valve position in the figure, and the air pipe a is changed to the conduit (
25) to communicate with the air chambers (17a) and (17b).
air exhaust.

On the other hand, when driving steadily on a good road, the steady running signal of the vehicle speed signal (S,) and the steady engine rotation signal (S2) are input in order to cut off engine operating noise. , set the three-way switching valve (26) to the water valve position shown by the broken line in the figure, and open the air chambers (17a) and (17b).
).

In addition, in the case of acceleration/deceleration and sudden braking, engine shaking can be handled by inputting the vehicle speed signal (S, ) and throttle position signal (S3) in the former case, and by inputting the vehicle speed signal (S, ) in the latter case. By inputting the and brake signals (S, ), the three-way switching valve (26) is set to the air exhaust operation at the solid line water valve position.

Further, if it is necessary to improve the ride comfort when driving on a rough road, the three-way switching valve (26) is set to the air exhaust operating state by inputting the vehicle speed signal (S, ) and the rough road surface condition detection signal (S4).

In this way, soundproofing and vibration damping can be controlled reliably and easily in accordance with the operating conditions of the vehicle.

(Effects of the Invention) As described above, the vibration isolating device according to the present invention allows the vibration isolating performance and other characteristics to be easily adjusted by introducing and discharging air into the air chamber provided in the liquid chamber. Moreover, the flexible thin film that forms the air chamber is attached to a rigid partition plate, and is not affected by the front-back, left-right movement of the anti-vibration base due to loads and vibrations, so the thin film is not difficult to control. It has excellent durability because it does not undergo excessive force or deformation, and is not damaged or partially weakened.

In particular, in relation to the rain and air chambers formed on both sides of the partition plate surrounded by liquid chambers, the amount of displacement of the thin elastic body, thin film body, or flexible membrane that is displaced in response to the movement of air due to vibration is calculated. By providing a stopper plate to limit vibrations, it is possible to obtain high damping performance with a low dynamic spring constant against low frequency and small amplitude vibrations, and the range of adjustment of characteristics can be further expanded.
It is possible to control extremely detailed characteristics according to the vehicle's driving conditions, improving ride comfort and stabilizing steering.

In addition, since the configuration has air chambers formed on both sides of the partition plate, even if the volume of the air chamber is small, the variable range of the characteristics as a vibration isolator can be widened. It is possible to achieve improved performance.

[Brief explanation of drawings]

FIGS. 1, 2, and 3 are an overall longitudinal sectional view, a longitudinal sectional view showing essential parts, and an overall longitudinal sectional view showing each embodiment of the present invention, and FIG. 4 is a partition plate portion in FIG. 3. , FIG. 5 is a diagram showing the relationship between vibration frequency and dynamic spring constant, FIG. 6 is a diagram showing the relationship between vibration frequency and damping coefficient, and FIG. 7 is a control system according to an example of the present invention. It is a diagram. (1)...Vibration isolation base, (5)...Flexible membrane, (
6)...liquid, (7)...partition plate, (8a),
(8b)...liquid chamber, (9)...orifice, (lla), (flb)...stopper plate consisting of a thin plate part (2)...air circulation hole, 01...thin film elasticity Body, 00... Thin plate body, (16a), (16b) -Fitl [membrane, (17
a) , (17b) -Air chamber, Ql...Air circulation hole, (2+11...Stopper plate, (21)...Liquid circulation hole, (25)...Conduit, (26)... Switching valve device.

Claims (1)

[Claims] 1. A liquid-filled inner chamber formed between a vibration-proof base made of an elastic material such as rubber and a flexible membrane is separated by a partition plate.
In a liquid damping type vibration isolator which is divided into two liquid chambers and communicated between the two liquid chambers by an orifice provided on the outer periphery of the partition plate, on both sides of the partition plate except for the opening of the orifice to each liquid chamber. An air chamber capable of holding air is formed in the space surrounded by the thin film and the partition plate by attaching a flexible thin film adjacent to the partition plate in a sealed state at the peripheral edge thereof, and at the same time, a portion of the partition plate existing in the air chamber is formed. is formed by a flexible thin film-like elastic body whose periphery is fixed, and a stopper plate consisting of a plate having a plurality of air circulation holes with narrow gaps on both sides sandwiching the thin film-like elastic body. , a liquid damping type vibration isolator, characterized in that an air circulation line is provided in the air chamber for introducing and discharging air into and out of the air chamber at least on the side of the vibration isolating base, thereby making the vibration isolating characteristics variable. . 2. The inner chamber filled with liquid formed between the vibration isolating base made of an elastic material such as rubber and the flexible membrane is separated by a partition plate.
In a liquid damping type vibration isolator which is divided into two liquid chambers and communicated between the two liquid chambers by an orifice provided on the outer periphery of the partition plate, on both sides of the partition plate except for the opening of the orifice to each liquid chamber. An air chamber capable of holding air is formed in the space surrounded by the thin film and the partition plate by attaching a flexible thin film adjacent to the partition plate in a sealed state at the peripheral edge thereof, and at the same time, a portion of the partition plate existing in the air chamber is formed. A stopper plate consisting of a thin plate body placed in a free state so as to be movable in the axial direction, and a plate having narrow gaps on both sides of the thin plate body and a plurality of air circulation holes smaller in diameter than the thin plate body. A liquid damping device characterized in that vibration damping characteristics are made variable by providing an air circulation line for introducing and discharging air into and out of the air chamber at least on the side of the vibration isolating base. type vibration isolator. 3. A liquid-filled inner chamber formed between a vibration-proof base made of an elastic material such as rubber and a flexible membrane is divided into two liquid chambers by a partition plate, and a liquid chamber is provided on the outer periphery of the partition plate. In a liquid damping type vibration isolator in which two liquid chambers are communicated with each other by an orifice, a flexible thin film is placed adjacent to both sides of the partition plate, excluding the opening of the orifice to each liquid chamber, in a sealed peripheral edge state. attached to the thin film and the partition plate to form an air chamber that can hold air in the space surrounded by the thin film and the partition plate, and provide a passageway that communicates the air chambers on both sides to the part of the partition plate that exists in the air chamber, Furthermore, a stopper plate having a plurality of liquid flow holes is disposed at least on the vibration-proofing base side of the flexible thin film so as to be close to the outer liquid chamber side, A liquid damping type vibration isolator characterized in that vibration damping characteristics are made variable by providing an air circulation line for introducing and discharging air into and out of an air chamber on the vibration isolating base side. 4. The air circulation line includes a conduit that extracts negative pressure from the intake side of the engine supported by the liquid damping type vibration isolator, and a switching valve device that opens the air chamber to the atmosphere or connects it to the conduit. The liquid damping type vibration isolator according to claim 1, 2 or 3, comprising: 5. For idling vibration and cranking vibration when the car is stopped, the car stop signal and engine low rotation signal are used to
5. A liquid damping type vibration isolator according to claim 1, wherein air is discharged from the air chamber. 6. The liquid damping type vibration damping device according to claim 1, 2, 3, 4 or 5, wherein air is introduced into the air chamber by a vehicle speed signal and an engine rotation signal in response to engine noise during steady running. 7. In response to an engine shaking phenomenon during acceleration/deceleration or sudden braking, air is discharged from the air chamber in response to a vehicle speed signal and a throttle position signal, or a vehicle speed signal and a braking signal. The liquid damping type vibration isolator according to item 4, 5 or 6. 8. The liquid damping according to claim 1, 2, 3, 4, 5, 6, or 7, wherein air is discharged from the air chamber in response to a vehicle speed signal and a road surface condition detection signal in response to vibrations when traveling on a rough road. type vibration isolator.