JPH07139580A - Liquid sealing vibration isolator - Google Patents

Abstract

PURPOSE:To prevent vibration transmission well in a wide frequency range by preventing any increase in a movable spring constant in a high frequency vibration range. CONSTITUTION:A liquid sealing vibration isolator is provided with a main liquid chamber A whose chamber wall is made of a rubber vibration insulator 1, and an auxiliary liquid chamber B communicated with the main liquid chamber A through a throttled flow passage 31, and for maintaining sealed liquid for making communication through the throttled flow passage 31 with a rubber film 2 serving as a chamber wall. A part of the chamber wall of the main liquid chamber A is made of a rubber film 4, a butterfly valve 5 is arranged in its inner position, and the rubber film 4 is isolated from the main liquid chamber A by means of closing motion of the butterfly valve 5. The butterfly valve 5 is opening/closing operated by a motor 6.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid filled vibration damping device,
Particularly, the present invention relates to a liquid-filled anti-vibration device capable of effectively preventing vibration transmission in a wide frequency range.

[0002]

2. Description of the Related Art A liquid-filled type is used as an anti-vibration device capable of effectively preventing vibration transmission of a vehicle engine, and its basic structure is shown in FIG. In the figure, a main liquid chamber A is formed with a container-shaped thick anti-vibration rubber body 1 opening downward, and its opening is closed by a thick plate-shaped partition member 3 in which a throttle channel 31 is formed. Has been done.

A vehicle engine is mounted on the antivibration rubber body 1 via an upper plate 11, and the outer peripheral edge of the opening of the antivibration rubber body 1 is joined to the inner periphery of the opening of the cylindrical casing 7. The casing 7 is a bottomed tubular body, and is fixed to a vehicle frame (not shown) by a leg portion 71 projecting from the outer periphery of the lower end thereof. The partition member 3
Inside the casing 7 below, a rubber film 2 whose outer periphery is joined to the inner wall of the casing 7 is freely deformable, and a sub liquid chamber B is formed above the rubber film 2. It communicates with room A. Below the rubber film 2 is an air chamber C, which communicates with the outside air through a through hole 72 provided in the bottom wall of the casing 7.

When vibration is input from the vehicle engine, the anti-vibration rubber body 1 expands and contracts vertically in response to the vibration input, the volume of the main liquid chamber A changes, and the enclosed liquid passes through the throttle passage 31 and the sub liquid chamber. Distributed to B. Therefore, low-frequency vibration of about 5 to 10 Hz such as engine shake vibration is effectively damped by the resistance that the enclosed liquid receives when flowing through the throttle passage 31. Further, the idling vibration of about 15 to 30 Hz is favorably absorbed because the filled liquid in the throttle channel 31 resonates and the dynamic spring constant of the device sharply decreases in this region. This effect is shown in FIG. 6, where the solid line is the dynamic spring constant,
The broken line shows the frequency characteristic of the attenuation coefficient. Point A shows the engine shake vibration range, and point B shows the idling vibration range.

[0005]

By the way, in the high frequency vibration range of the engine (the point C range in FIG. 6) which produces muffled noise,
It is necessary to reduce both the damping coefficient and the dynamic spring constant of the vibration isolator to absorb the vibration. However, in this high frequency range, it becomes difficult for the liquid to flow to the throttle channel 31, so that the expansion spring of the main liquid chamber A increases, and the dynamic spring constant of the entire device increases toward the high frequency side, which causes muffled noise. There is a problem that the reduction is not performed properly.

Therefore, the present invention solves such a problem, and provides a liquid-filled vibration isolator capable of preventing an increase in a dynamic spring constant in a high frequency vibration range and favorably preventing vibration transmission in a wide frequency range. With the goal.

[0007]

The structure of the present invention will be described. Firstly, the first structure is connected to a vibrating body and expands and contracts in response to a vibration input and does not substantially change due to a change in internal pressure.
Of the main liquid chamber A having a chamber wall formed by the wall member 1 and the second main liquid chamber A communicating with the main liquid chamber A through the throttle channel 31 and freely deformable
And a sub liquid chamber B for holding the enclosed liquid that flows through the throttle channel 31 and a part of the main liquid chamber A can be freely deformed. The third wall member 4 and the valve member 5 is arranged at an inner position of the third wall member 4, and the valve member 5 is closed by the third operation.
The wall member 4 is separated from the main liquid chamber A, and the valve driving means 6 for opening and closing the valve member 5 in response to the vibration input from the vibrating body is provided.

[0008]

When the engine shake vibration or the idling vibration is input, the valve driving means 6 closes the valve member 5. As a result, the freely deformable third wall member 4 is isolated from the main liquid chamber A, so that when the first wall member 1 is deformed in response to the input vibration, the internal pressure of the main liquid chamber changes greatly and the throttle flow is reduced. The enclosed liquid flows into the sub liquid chamber B through the passage 31.
Thus, the engine shake vibration is attenuated and reduced by the resistance of the enclosed liquid flowing through the throttle passage 31, and the idling vibration is absorbed and reduced by the resonance of the enclosed liquid flowing through the throttle passage 31.

When a high frequency muffled sound vibration is input, the valve member 5 is opened by the valve driving means 6 so that the freely deformable third wall member 4 faces the main liquid chamber A. It forms part of the room wall. However, even if the first wall member 1 deforms due to the input of muffled sound vibration, the change in the internal pressure of the main liquid chamber A is alleviated by the deformable third wall member 4,
The dynamic spring constant of the device is kept low, and good vibration absorption is achieved.

[0010]

EXAMPLE In FIG. 1, a casing 7 having a bottomed cylindrical shape
Is fixed to a vehicle frame (not shown) by a leg portion 71 protruding from the outer periphery of the lower end thereof. A thick bowl-shaped anti-vibration rubber body 1 is covered in the opening of the casing 7, and a vehicle engine is mounted on the top plate 11 joined to the top surface thereof.

In the closed casing 7, a tubular partition member 3 having a substantially U-shaped cross section is provided so as to cross the casing 7.
A rubber film 4 is provided by partitioning the partition member 3 into upper and lower parts, and the closed space having the rubber film 4 and the vibration isolating rubber body 1 as a chamber wall serves as a main liquid chamber A. There is. In addition, behind the rubber film 4 is an air chamber D that communicates with the outside air through a through hole 32 that penetrates the partition member 3 and the side wall of the casing 7.

A disc-shaped butterfly valve 5 is disposed above the rubber film 4 in the main liquid chamber A, and the butterfly valve 5 is provided with a rotary shaft 51 installed between the side walls of the partition member 3. It can be opened and closed by rotating. One end of the rotary shaft 51 extends outside the casing 7 and is connected to the rotary actuator 6. When the butterfly valve 5 is in the open state shown in the figure, the rubber film 4 faces the main liquid chamber A. On the other hand, when the butterfly valve 5 is closed, the space A1 directly above the rubber film 4 is closed and the rubber film 4 is closed. The membrane 4 is separated from the main liquid chamber A.

This will be described with reference to FIG. 2. The butterfly valve 5
Is in a vertical posture as shown in (1) of the figure in the opened state, the space A1 directly above the rubber film 4 communicates with the upper main liquid chamber A, and the rubber film 4 is one of the chamber walls of the main liquid chamber A. Make up part.
At the time of closing, the butterfly valve 5 is rotated clockwise and abuts against the stoppers 33 and 34 protruding from the side wall of the partition member 3 to be in a horizontal posture as shown in FIG. In this state, the space A1 immediately above the rubber film 4 is shut off from the upper main liquid chamber A. The butterfly valve 5 is always urged to rotate clockwise by the rotary actuator 6 in order to maintain the closed state in the horizontal posture.

The partition member 3 has a narrowed flow passage 31 penetrating through the side wall and the bottom wall thereof in a substantially L-shape. A rubber film 2 is provided below the partition member 3 so as to traverse the inside of the casing 7, and a sub liquid chamber B is formed above the rubber film 2 as a chamber wall. 31 communicates with the main liquid chamber A. Below the rubber film 2 is an air chamber C that communicates with the outside air through a through hole 72 provided in the bottom wall of the casing 7.

The rotary actuator 6 is connected to an external controller 8 as shown in FIG. 3, and is driven in the forward and reverse directions according to the running state of the vehicle as described later to open and close the butterfly valve 5. Output signals from an engine speed sensor, a vehicle speed sensor, an acceleration pickup mounted on the engine, etc. are input to the controller 8, and the controller 8 discriminates each vibration range such as engine shake, idling, and muffled sound from these signals. And outputs a rotation signal to the rotary actuator 6. The controller 8 is supplied with power from the battery 81.

In the liquid-filled vibration isolator having such a structure, the butterfly valve 5 is closed in the low frequency engine shake vibration region and the idling vibration region. As a result, the rubber film 4 is separated from the main liquid chamber A, and the chamber wall of the main liquid chamber A is composed only of the vibration-proof rubber body 1 which is not substantially deformed by the change of the internal pressure. When the anti-vibration rubber body 1 expands and contracts due to the vibration input in this state, the enclosed liquid flows into the sub liquid chamber B through the throttle channel 31 in accordance with the change in the internal pressure of the main liquid chamber A.

In the engine shake vibration range (point A in FIG. 4), the damping coefficient of the device (broken line in the figure) is large due to the resistance received by the enclosed liquid flowing through the throttle passage 31, and the shake vibration can be quickly attenuated and reduced. . Further, in the idling vibration range (point B in the figure), the enclosed liquid flowing through the throttle channel 31 resonates, so that the dynamic spring constant (solid line in the figure) of the device sharply decreases, and the idling vibration is quickly absorbed and reduced. To be

In the high-frequency muffled sound vibration range (point C in the figure), the butterfly valve 5 is opened. As a result, the rubber film 4 faces the main liquid chamber A and constitutes a part of the chamber wall, and even if the vibration damping rubber body 1 expands and contracts due to the input of muffled sound vibration, the main liquid chamber A The change in the internal pressure of is absorbed by the free deformation of the rubber film 4. The dynamic spring constant of the device is sufficiently small, and as a result, muffled sound vibration can be well absorbed and reduced.

Although the valve member for isolating the rubber film is not necessarily a butterfly valve, it is advantageous in that it can open and close a large area with a simple and compact structure.

In the above embodiment, the case where the main liquid chamber is constituted by the chamber wall and the vibration-proof rubber body has been described, but bellows or the like may be used.

[0021]

As described above, according to the liquid filled vibration damping device of the present invention, it is possible to effectively prevent vibration transmission in a wide frequency range, and it can be suitably used as an engine mount or the like.

[Brief description of drawings]

FIG. 1 is an overall cross-sectional view of a vibration isolator showing an embodiment of the present invention.

FIG. 2 is a cross-sectional view of essential parts showing an open / closed state of a butterfly valve.

FIG. 3 is a rotary actuator power supply system diagram of the vibration isolator.

FIG. 4 is a frequency characteristic diagram of a vibration isolation device.

FIG. 5 is an overall cross-sectional view of a conventional device.

FIG. 6 is a frequency characteristic diagram of a conventional device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 anti-vibration rubber body (first wall member) 2 rubber film (second wall member) 3 partition member 31 throttle channel 4 rubber film (third wall member) 5 butterfly valve (valve member) 6 rotary actuator (Valve driving means) A main liquid chamber B sub liquid chamber

Claims (1)

[Claims] 1. A main liquid chamber having a chamber wall formed by a first wall member that is connected to a vibrating body and expands and contracts in response to a vibration input and does not substantially deform due to a change in internal pressure,
A second deformable second fluid communicating with the main liquid chamber through the throttle channel
And a sub-liquid chamber for holding the enclosed liquid flowing through the throttle channel, and a part of the chamber wall of the main liquid chamber is freely deformable. The valve member is formed of a wall member, and the valve member is disposed at an inner position of the third wall member so that the third wall member is separated from the main liquid chamber by the closing operation of the valve member, and the vibration is generated. A liquid-filled anti-vibration device, comprising valve drive means for opening and closing the valve member in response to vibration input from the body.