JPH03103635A - Liquid sealing type vibration proof device - Google Patents

Abstract

PURPOSE:To attenuate vibration in a wide frequency area by sealing electroviscous liquid which increases in viscosity according to the application of electric field in two liquid chambers, and providing a movable wall which moves based on pressure difference between both sides of an auxiliary liquid chamber and electrodes. CONSTITUTION:A vibration proof rubber body 1 is composed of a cup-like thick rubber opened downwardly, onto whose flat top an engine is mounted end fixed. An opening of the rubber body 1 is closed by a partition wall 2, while a rubber film 4 is arranged below the partition well 2. A vessel-like bottom plate 5, which is provided below the rubber film 4, is calkingly connected to an side plate 6 extending from the rubber body 1 under the state that the edge of the opening of the plate 5 is abutted against the outer peripheral edge of the rubber film 4. Electroviscous fluid is sealed in a sealed space formed by the rubber body 1 and the rubber film 4. A main liquid chamber A and a sub-liquid chamber B are formed respectively above and below the partition wall 2. A rubber movable wall 3 is arranged across an auxiliary liquidchamber C, while film electrodes are formed on both sides of a thin film of the movable wall 3 and inner faces of upper and lower plates opposing thereto.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a liquid-filled vibration isolator, and more particularly to a liquid-filled vibration isolator that can effectively damp both large-amplitude vibrations and absorb small-amplitude vibrations.

[Prior Art] Liquid-filled vibration isolators are capable of effectively attenuating particularly low-frequency, large-amplitude vibrations through the action of a sealed liquid, and are being applied to vehicle engine mounts and the like. In such a vibration isolator, since it is possible to make the vibration isolator rubber body have a low dynamic spring, it is possible to absorb small high frequency vibrations relatively well.
Various efforts have been made.

An example of this will be explained with reference to FIG.
A sub-liquid chamber B is formed which is divided by a partition wall 2 and has a thin rubber membrane 4 as a chamber wall.

The partition wall 2 is composed of a ring-shaped frame body 23 and a rubber movable wall 3 provided in the opening of the frame body 23.
B communicates with each other through a throttle channel F formed on the outer periphery of the frame body 23. The outer peripheral edge of the movable wall 3 is fixed to the inner peripheral wall of the opening of the frame body 23, and when the internal pressure of the main liquid chamber A changes with respect to the sub-liquid chamber B which is always at atmospheric pressure, the movable wall 3
The thin center part of the body moves within a certain range to keep internal pressure changes small.

In this structure, when a large amplitude vibration is input, the internal pressure of the main liquid chamber A changes greatly due to the deformation of the vibration isolating rubber body 1, and the above internal pressure change cannot be suppressed by the movement of the movable wall 3, and the sealing liquid flows into the throttle channel. It flows through F to the sub-liquid chamber B, producing a large vibration damping force.

Although the internal pressure of the main liquid chamber A changes even when small-amplitude vibrations are input, this internal pressure change is kept extremely small by the movement of the movable wall 3, and as a result, good vibration absorption is achieved.

[Problem M to be solved by the invention] By the way, in the conventional liquid-filled vibration isolator described above, the movable wall 3 moves within a certain range even when a large amplitude vibration is input, so the internal pressure in the main liquid chamber A increases accordingly. is attenuated, and a sufficiently high attenuation characteristic may not be obtained. This problem becomes serious when the movable range of the movable wall 3 is increased in order to absorb high-frequency vibrations with relatively large amplitudes.

The present invention solves this problem, and is a liquid-filled vibration isolator equipped with a movable wall, in which a liquid-filled vibration damping device that satisfactorily exhibits both high damping characteristics against low-frequency, large-amplitude vibrations and vibration-absorbing characteristics against high-frequency, small-amplitude vibrations. The purpose is to provide a vibration isolator.

[Means for Solving the Problems] To explain the structure of the present invention, a liquid-filled vibration isolator includes a partition that is connected to a vibration isolating rubber body 1 (FIG. 1) connected to a vibrating body through a throttle channel F. A pair of liquid chambers A and B separated by wall 2
An electroviscous liquid whose viscosity increases due to the action of an electric field is sealed in these liquid chambers A and B, and an auxiliary liquid chamber C is formed in the partition wall 2 and communicates with each of the liquid chambers A and B. The auxiliary liquid chamber C includes the liquid chamber A. Electrodes 41 and 42 are provided with a movable wall 3 that is partitioned on the B side and move according to the pressure difference between both sides, and that form an electric field in the auxiliary liquid chamber C.
(Fig. 2) is provided.

[Operation] In the liquid-filled vibration isolator having the above configuration, when a large amplitude vibration is input, electricity is applied to the electrodes 41 and 42 to form an electric field in the auxiliary liquid chamber C. Due to this electric field, the viscosity of the electrorheological liquid on both sides of the movable wall 3 in the auxiliary liquid chamber C increases rapidly, making it difficult for the movable wall 3 to move. Therefore, even if a pressure difference is generated on both sides due to a change in the internal pressure of the liquid chambers A and B, which are greatly deformed by vibration input, the movable wall 3 hardly moves, and the increase in the internal pressure is not reduced. The sealing liquid efficiently flows between the two liquid chambers A and B through the throttle channel F, resulting in a high damping effect.

Furthermore, by adjusting the voltage applied to the electrodes 41 and 42, the frequency at which high attenuation occurs can be changed.
Vibration damping over a wide frequency range is possible.

When a small amplitude vibration is input, the power supply to the electrodes 41 and 42 is stopped. The electric field in the auxiliary liquid chamber C is eliminated, the viscosity of the electrorheological liquid is reduced, and the movable wall 3 becomes freely movable. Therefore, even if the internal pressures of the liquid chambers A and H change somewhat due to vibration input, this internal pressure change is suppressed to a very small level by the movement of the movable wall 3, and a good vibration absorption effect is achieved.

[Embodiment] In FIG. 1, a vibration isolating rubber rest 1 is made of a bowl-shaped thick rubber that opens downward, and an engine as a vibrating body is mounted and fixed on its flat top surface. The opening of the vibration isolating rubber body 1 is closed by a partition wall 2, the details of which will be described later. A rubber membrane 4 is disposed below the partition wall 2, and its outer periphery is in close contact with the lower surface of the outer periphery of the partition wall 2. .

A container-shaped bottom plate 5 is disposed below the rubber membrane 4, and is caulked and connected to a side plate 6 extending from the anti-vibration rubber body 1, with its opening edge in contact with the outer peripheral edge of the rubber membrane 4. There is.

An electrorheological liquid is sealed in the sealed space formed by the vibration-proof rubber body 1 and the rubber film 4, and a main liquid chamber A is located above the partition wall 2, and a sub-liquid chamber B is located below the partition wall 2. are formed respectively.

Details of the partition wall 2 will be explained with reference to FIG. 2. The partition wall 2 is constructed by stacking a circular upper plate 21 (Fig. 3) and a lower plate 22 at the outer periphery, and the inner peripheries of the upper plate 21 and the lower plate 22 face each other at a certain distance from each other. A chamber C is formed. This auxiliary liquid chamber C communicates with the main liquid chamber A and the auxiliary liquid chamber B through a plurality of round holes 211 and 221 provided in the upper side plate 21 and the lower side plate 22, respectively.

A movable rubber wall 3 is disposed in the auxiliary liquid chamber C across the auxiliary liquid chamber C, and the movable wall 3 is thin in most parts except for the outer periphery and is freely deformable. A protruding mounting rib 3l having a T-shaped cross section is held between the upper measuring plate 21 and the lower plate 22. The upper half of the auxiliary liquid chamber C divided by the movable wall 3 communicates with the main liquid chamber A, and the lower half communicates with the auxiliary liquid chamber B.

Both sides of the thin wall portion of the movable wall 3 and the upper plate 21 opposite thereto
And on each inner surface of the lower plate 22, a membrane electrode 4 is provided.
, 42 are connected to each other, the electrode 41 is grounded by a lead wire 43, and the electrode 42 is connected to a power source outside the device by a lead wire 44, respectively.

Incidentally, a rectangular groove 23 is formed all around the four outer peripheral surfaces of the upper plate 2l, and the open part of the groove 23 is closed by the side plate 6 when the partition wall 2 is installed at a predetermined position. hand(
Fig. 2) At an appropriate position, a throttle flow path F is formed that communicates with the main liquid chamber A and the sub-liquid chamber B.

The operation of the liquid-filled vibration isolator having the above structure will be explained below.

When low-frequency, large-amplitude vibrations such as engine shake are input, the electrodes 41 and 42 are energized to form an electric field within the auxiliary fluid chamber C. Due to this electric field, the viscosity of the electrorheological liquid between the movable wall 3 and the upper plate 2l or the lower plate 22 in the auxiliary liquid chamber C increases rapidly, making it difficult for the movable wall 3 to move.

As a result, a pressure difference is created between the main liquid chamber A whose internal pressure increases with the vibration input and the sub-liquid chamber B whose internal pressure is at atmospheric pressure, and an acting force due to this pressure difference acts on the movable wall 3. It hardly moves.

In this way, the increase in the internal pressure of the main liquid chamber A is not reduced, and the sealing liquid efficiently flows between the two liquid chambers A and B through the throttle channel F, resulting in a high damping effect. This is shown by line X in FIG. 4, and the vibration isolator has a sufficiently large peak value of the damping coefficient near 10 Hz. Incidentally, the line X1 in the figure shows the characteristics of the conventional device, and it is known that the damping effect is reduced by the movement of the movable wall.

Note that by adjusting the voltage applied to the electrodes 4l and 42, the frequency at which the attenuation coefficient shows the peak value can be changed (
From line X to line y in FIG. 4), it is possible to reduce vibration input over a wide frequency range.

When high-frequency, small-amplitude vibrations such as muffled sound vibrations are input, the power supply to the electrodes 41 and 42 is stopped.

As a result, the electric field within the auxiliary liquid chamber C is eliminated, the viscosity of the electrorheological liquid is reduced, and the movable wall 3 becomes freely movable.

Therefore, even if the internal pressure of the main liquid chamber A changes to some extent due to vibration input, this internal pressure change is kept to a very small level by the movement of the movable wall 3, and a good vibration absorption effect is achieved.

[Effects of the Invention] According to the liquid-filled vibration isolator of the present invention, - high damping characteristics and good vibration absorption characteristics can be achieved by filling the periphery of the movable wall with an electroviscous liquid and controlling the application of an electric field thereto. This has enabled vibration damping over a wide frequency range.

[Brief explanation of drawings]

Figures 1 to 4 show an embodiment of the present invention, in which Figure 1 is an overall sectional view of the device, Figure 2 is a sectional view of a partition wall, Figure 3 is a plan view thereof, and Figure 4 is a sectional view of the device. Figure 5 shows the attenuation characteristics of
The figure is an overall sectional view of a conventional device. ■... Vibration-proof rubber body 2... Partition wall 21... Upper plate 22... Lower plate 211, 221... Circular hole 3... Movable wall 41, 42... Electrode 45...・Power supply A...Main liquid chamber (liquid chamber) B...Sub-liquid chamber (liquid chamber) C...Sleeve auxiliary liquid chamber F...Restricted channel circumference Figure 3

Claims (1)

[Claims] A pair of liquid chambers are formed in a vibration isolating rubber body connected to a vibrating body and are connected by a throttle channel and separated by a partition wall, and an electrorheological liquid whose viscosity increases due to the action of an electric field is sealed in these liquid chambers. , an auxiliary liquid chamber communicating with each of the liquid chambers is provided within the partition wall, and a movable wall is provided within the auxiliary liquid chamber that partitions the auxiliary liquid chamber to the side of each of the liquid chambers and moves according to the pressure difference between the two sides, A liquid-filled vibration isolator characterized in that an electrode for forming an electric field is provided in the auxiliary liquid chamber.