JPH03144133A - Liquid seal vibration isolator - Google Patents

Abstract

PURPOSE:To reduce the cost by providing a cylinder chamber filled with electroviscous liquid at a part of chamber walls deformed accompanying vibration input, by providing a piston in this chamber and connecting it to a vibration body, and by providing electrodes and a means for applying current according to the vibration input in the chamber. CONSTITUTION:A cylinder chamber 4a filled with electroviscous liquid whose viscosity is increased corresponding to strength of an electric field is provided at a part of chamber walls 1 and 2, and a piston 5 is provided here and connected to a vibration body. An electrode 4 and an electrode 5 (serving also as a piston) for forming an electric field in the cylinder 4a are provided, and a current applying means 6 for applying current to the electrodes 4 and 5 according to vibration input is provided. When large vibration is input, an electric field is formed, viscosity of the electroviscous liquid is increased, and it gets hard for the piston 5 to move. As a result, vibration deforms the chamber wall 1 of a liquid chamber A. Then, sealed liquid in the liquid chamber A flows to a liquid chamber B through a contracted flow passage 31 of a partition 3 so as to generate vibration damping force. When applying of current is stopped, viscosity of the viscous liquid is reduced and micro vibration is absorbed by free movement of the piston 5.

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 whose characteristics can be changed in response to vibration input.

[Prior Art] A liquid-filled vibration isolator forms a liquid chamber filled with liquid inside a rubber wall or the like that deforms due to vibration input, and divides this liquid chamber with a partition wall having a constricted flow path. The sealed liquid is caused to flow between the partitioned liquid chambers through the constricted flow path, thereby exhibiting an effective vibration damping effect.

By the way, when such a liquid-filled vibration isolator is used in a vehicle engine mount, etc., the required device characteristics differ depending on the type of engine vibration. In other words, it is desirable to generate a large vibration damping force for low-frequency, large-amplitude vibrations such as engine shake, and on the other hand, for high-frequency slight vibrations, it is desirable to reduce the dynamic spring constant of the device as much as possible to absorb vibrations. It is hoped that this will be done.

Therefore, in the past, the cross-sectional area of the throttle flow path was made variable.
2-127539], or by providing an air chamber in a rubber wall to change the internal pressure (Japanese Utility Model Publication No. 62-20231), devices that satisfy the above requirements have been proposed.

[Problems to be Solved by the Invention] However, each of the devices proposed above has problems such as the structure of the vibration isolating device being complicated or requiring a pressure source, piping, switching valve, etc. outside the device, and the device is significantly An increase in costs and installation space is unavoidable.

The present invention solves this problem, and aims to provide a liquid-filled vibration isolator with variable characteristics at a low cost and with a compact structure.

[Means for Solving the Problems] To explain the present invention in detail, the liquid chambers A and B constituted by the chamber walls 1.2 (Fig. In a liquid-filled vibration isolator which is partitioned by a partition wall 3 and which damps vibrations by causing a filled liquid to flow between the partitioned liquid chambers A and B through the throttle channel 31, a part of the chamber wall is provided. A cylinder chamber 4a filled with an electrorheological liquid whose viscosity increases according to the strength of the electric field is provided, a piston member 5 is provided in the cylinder chamber 4a and connected to the vibrating body, and It is provided with an electrode 4.5 for forming an electric field within 4a, and an energizing means 6 for energizing the electrode 4.5 in response to vibration input.

[Operation 1] In the liquid-filled vibration isolator having the above configuration, when large vibrations are input, when the electrodes 4.5 are energized, an electric field is formed and the viscosity of the electrorheological liquid in the cylinder chamber 4a increases, causing the piston to As a result of the member 5 becoming difficult to move, the vibration is caused by the piston member 5.
The liquid enters the chamber wall ↓ of the liquid chamber A through the cylinder chamber 4a and deforms it. As a result, the sealing liquid in the liquid chamber A flows through the throttle channel 31, producing a large vibration suppressing force.

When the electricity supply to the electrodes 4.5 is stopped when a minute vibration is input, the electric field is eliminated, the viscosity of the electrorheological liquid is reduced, and the piston 5 becomes freely movable.

Therefore, the vibration input is absorbed by the free movement of the piston 5 without being transmitted to the chamber wall 1 of the liquid chamber A.

[Example] In FIG. 1, a bowl-shaped thick rubber wall l that opens downward is closed by a partition plate 3, and a thin rubber sheet 2 is tightly attached to the outer periphery below the partition plate 3. The rubber wall 1 and the rubber sheet 2 form a sealed space. A main liquid chamber A in which a liquid is sealed in this space, partitioned by the partition plate 3, and having the rubber wall 1 as a chamber wall.
This is an auxiliary liquid chamber B having the rubber sheet 2 as a chamber wall. These liquid chambers A and B communicate with each other through a throttle channel 31 formed on the outer periphery of the partition plate 3.

A cylindrical member 4 with one end closed and opening upward is embedded in the center of the rubber wall (2), and the opening is connected to a slightly thick rubber disc 7.
The inside is closed as a cylinder chamber 4a. This cylinder chamber 4a is filled with an electrorheological liquid whose viscosity increases depending on the applied electric field strength.

A piston member 5 is provided in the cylinder chamber 4a with a base 51 buried and fixed in the center of the rubber disc 7, and the piston member 5 is a thick metal disc (FIG. 2). It is formed at the tip of a rod portion 52 extending downward from the base portion 51.The outer periphery of the piston member 5 faces the inner wall of the cylindrical member 4 at a constant interval, and the inner wall is covered with insulating rubber of a constant thickness. The insulating rubber Jii41 on the bottom wall of the cylindrical member 4 is formed with a hole.

The rubber disc 7 is pre-compressed so as not to cause fatigue even if it is displaced relatively largely, and an insert ring 71 embedded in its outer periphery is caulked and fixed to the opening edge of the cylindrical member 4. A ring-shaped stopper plate 72 that prevents excessive upward deformation of the rubber disk 7 is similarly fixed by caulking.

A bolt portion 53 extends upward from the base portion 51, and the engine mounted on the base portion 51 is attached to the bolt portion 53.
Fix it by. The device is connected and fixed to the vehicle frame by bolts 91 of the bottom plate 9 which are caulked and fixed to the side plate 8 together with the partition plate 3 and the rubber sheet 2.

In addition, lead wires 61 and 62 are connected to the base 51 of the cylindrical member 7 and the piston member 5 from an external energizing device 6 and serve as electrodes, and when a voltage is applied from the energizing device 6, the cylinder chamber 4a An electric field is formed within.

In the liquid-filled vibration isolator having the above structure, when the engine is started or shake vibration is input, current is applied between the cylindrical member 4 and the piston member 5 from the energizing device 6. This energization creates an electric field within the cylinder chamber 4a, increasing the viscosity of the electrorheological fluid. In this state, when large vibrations such as cranking or shaking are input, the piston member 5 receives a large resistance force due to the increased liquid viscosity between its outer periphery and the inner wall of the cylindrical member 4, and its free movement is restricted. be done.

As a result, the rubber wall 1 of the main liquid chamber A is greatly deformed due to the vibration input, and the sealing liquid flows at high speed through the throttle channel 31 to the auxiliary liquid chamber B, producing a large vibration damping force. An example of this effect is shown by the line X in FIG. 3. The damping coefficient of the device becomes sufficiently large near 5 Hz, and vibrations are quickly reduced.

At this time, in response to excessive vibration input, the piston member 5 integrated with the rubber disk 7 will come into contact with the inner wall of the cylindrical member 4, or the rubber disk 7 itself will come into contact with the stopper plate 72, resulting in excessive deformation. is prevented.

The frequency characteristic of the device dynamic spring constant at this time is shown by line X in FIG.

When the vehicle is idling or when high-frequency vibrations are input while the vehicle is running, the energization of the energizing device 6 is stopped. As a result, the electric field within the cylinder chamber 4a disappears, and the viscosity of the electrorheological liquid decreases. In this state, the piston member 5 can move freely in response to vibration input, and the dynamic spring constant of the device at this time is suppressed to the small dynamic spring constant of the rubber disc 7. This is shown by the line y in FIG. 4, and the dynamic spring constant of the device is suppressed to a sufficiently small value to provide a good vibration absorption effect.

The device damping coefficient at this time is shown by line y in FIG.

In the above embodiment, the piston member 5 is supported by the rubber disk 7 in order to receive the static load of the engine, but when the static load is not received, the cylinder chamber 4a is closed with a rigid wall and the piston member 5 is supported by the rubber disk 7. The rod portion 52 of No. 5 may be slidably passed through the rigid wall, and its tip may be connected to the engine.

Furthermore, by linearly changing the voltage applied by the energizing device in response to the vibration input, it is possible to continuously control the characteristic change from line X to line y in FIGS. 3 and 4.

[Effects of the Invention] As described above, according to the present invention, without complicating the device's M4 construction or increasing the installation space due to external piping, etc.
A liquid-filled vibration isolator with variable characteristics can be realized at low cost and easily, and transmission of vibrations in a wide frequency range of vehicle engines and the like can be effectively prevented.

[Brief explanation of the drawing]

Fig. 2) is an overall vertical sectional view of a vibration isolating device showing an embodiment of the present invention, Fig. 2 is a sectional view taken along the line ■-■ of Fig. It is. 1... Rubber wall (chamber wall) 2... Rubber sheet (chamber wall) 3... Partition plate (partition wall) 31... Restricted channel 4... Cylindrical member (electrode) 4a... Cylinder chamber 5...Piston member (also serves as an electrode) 6...Electrifying device (energizing means) 7...Rubber disc Figure 1 Figure 3 Figure 5 Frequency (H?) Figure 4 Frequency (Hz)

Claims (1)

[Claims] The liquid chamber is made up of a chamber wall that deforms due to vibration input.
In a liquid-filled vibration isolator that is partitioned by a partition wall in which a throttle channel is formed, and in which a sealed liquid is caused to flow between the partitioned liquid chambers via the throttle channel to damp vibration, a part of the chamber wall is provided. To,
A cylinder chamber filled with an electrorheological liquid whose viscosity increases according to the strength of an electric field is provided, a piston member is provided in the cylinder chamber and connected to a vibrating body, and an electric field is formed in the cylinder chamber. A liquid-filled vibration isolator comprising: an electrode; and an energizing means for energizing the electrode in response to vibration input.