JPH04312231A - Liquid seal vibration isolating device - Google Patents

Abstract

PURPOSE:To effectively prevent the transmission of a wide range of vibration. CONSTITUTION:A device is provided with a main liquid chamber A having a thick rubber vibration isolator 11 to support an engine as a chamber wall and a subliquid chamber B having a rubber film 2 as the chamber wall, and these liquid chambers A, B are divided by a partitioning plate 3, which is provided with a flow passage 31 having a large diameter and a flow passage 32 having a small diameter, and the liquid chambers A, B communicate mutually through the flow passages 31, 32. The flow passage 31 is provided with a rotary valve 4 to change its sectional area. The rotary valve 4 is made to function with its properly kept opening to change a frequency to cause liquid resonance for absorbing or clamping desired vibrational input.

Description

[Detailed description of the invention]

0001

[Industrial Application Field] The present invention relates to a liquid-filled vibration isolator,
In particular, the present invention relates to a liquid-filled vibration isolator that can handle a wide range of vibration input.

0002

[Prior Art] When a liquid-filled vibration isolator is used in a vehicle engine mount, etc., various vibrations are input from the engine over a wide frequency range, so the vibration isolator always provides good vibration isolation against such vibrations. It is expected that it will demonstrate its characteristics. Therefore, for example, as seen in Japanese Utility Model Application Publication No. 1-71249, it has been proposed to change the vibration isolation characteristics by providing an on-off valve in one throttle flow path connecting two liquid chambers and changing the cross-sectional area of the flow path. has been done.

0003

However, in the above-mentioned conventional vibration isolating device, the characteristic variable range is narrow, and vibration transmission reduction over a wide range is not yet sufficient.

The present invention has been made to solve this problem, and an object of the present invention is to provide a liquid-filled vibration isolator that effectively prevents vibration transmission over a wider frequency range.

[0005]

[Means for Solving the Problems] To explain the structure of the present invention, a liquid-filled vibration isolator has two liquid chambers A and B that are connected to a vibrating body and deform in a complementary manner. ,B,
Two channels 3 that cause liquid resonance in vibration regions with different frequencies
A valve member 4 for changing the cross-sectional area of the flow passage is provided in the flow passage 31 that communicates with the flow passage 1 and 32 and that causes liquid resonance on the high frequency side, and a valve control means 5 that drives the valve member 4 to open and close in response to vibration input. It was established.

[0006]

[Function] In the vibration isolator having the above structure, when the valve member 4 is fully opened, most of the sealing liquid flows into the flow path 31, exhibiting a characteristic that causes liquid resonance on the high frequency side, and when fully closed, the sealing liquid flows into the flow path 2. The sealing liquid flows and exhibits the characteristic of causing liquid resonance on the low frequency side. When the valve member 4 is between fully open and fully closed, the sealing liquid is distributed to both channels 31 and 32 according to the degree of opening of the valve member 4, and a characteristic that causes liquid resonance in the intermediate frequency range is exhibited. Ru. In this way, the vibration reduction effect due to liquid resonance can be obtained in a wide range from low frequencies to high frequencies.

[0007]

[Embodiment] In FIG. 2, the left and right support legs 6 of the engine 6
2 are supported on the vehicle frame 7 by mounts M made of the vibration isolator of the present invention, and signal lines 51 for opening and closing the built-in valves, which will be described later, are connected to these engine mounts M from the valve control circuit 5. . The valve control circuit 5 receives vehicle speed and engine rotational speed signals as well as an output signal from an acceleration sensor 61 provided in the engine.

Details of the engine mount M are shown in FIG.
The mount M has a main liquid chamber A whose chamber wall is a thick-walled circular vibration-proof rubber body 1 whose diameter expands downward, and a sub-liquid chamber A whose chamber wall is a thin rubber membrane 2 separated from this by a partition plate 3. It has a room B. The engine 6 has an upper plate 1 connected to the top surface of the vibration-proof rubber body 1.
The mount M is bolted to the vehicle frame 7 by means of a bottom plate 13 that supports a cylindrical side plate 12 joined to the opening edge of the vibration isolating rubber body 1 from below.

A large-diameter flow path 31 is formed on the inner circumference of the partition plate 3, and both ends thereof open to the upper and lower liquid chambers A and B. is provided, and is rotated by an unillustrated drive mechanism in accordance with the output of the signal line 51 to change its opening degree. The sealing liquid flowing through this flow path 31 is heated at 20H when the rotary valve 4 is fully open as shown.
Liquid resonance occurs near z. A small-diameter groove is formed almost all around the outer circumferential surface of the partition plate 3 to form a flow path 3 that communicates with both liquid chambers A and B.
2, and when the sealing liquid flows only through the flow path 32, liquid resonance occurs at a low frequency around 10 Hz.

Changes in the characteristics of the liquid-filled vibration isolator having the above structure are shown in FIGS. 3 and 4. When the vehicle speed signal is zero and the engine speed indicates the idle speed, the valve control circuit 5
The rotary valve 4 is fully opened. As a result, most of the sealing liquid flows into the large-diameter flow path 31, causing liquid resonance at around 20 Hz. The device spring constant at this time is the line Ka in Figure 3.
In this frequency range, the spring constant becomes minimum and effective vibration absorption is achieved. The device damping coefficient at this time is the line Ca
Indicated by

When the acceleration sensor detects shake vibration input while the vehicle is running, the rotary valve 4 is fully closed. All of the sealing liquid flows into a long channel 32 with a small diameter for 10H.
Liquid resonance occurs near z. The device damping coefficient at this time is shown in Figure 4.
As shown by the line Cd, it reaches a maximum in this frequency range, and an effective vibration damping effect is achieved. The device spring constant in this state is shown by line Kd.

[0012] When vibrations due to engine rotation fluctuations are detected by the acceleration sensor during idling, the opening degree of the rotary valve 4 is set between fully open and fully closed depending on the frequency of vibrations generated. When the opening degree is large, the device spring constant is as shown in the line Kb and the device damping coefficient is shown in the line Cb in Fig. 3. When the opening degree is small, the device spring constant is shown as the line Kc and the device damping coefficient is shown as the line Cc. become. Therefore, vibrations are absorbed by the low spring constant or damped by the large damping coefficient.

[0013]

As described above, according to the vibration isolating device of the present invention, vibration transmission can be effectively prevented over a wide frequency range.

[Brief explanation of drawings]

FIG. 1 is an overall sectional view of a liquid-filled vibration isolator.

FIG. 2 is an overall configuration diagram when a liquid-filled vibration isolator is used in an engine mount.

FIG. 3 is a device characteristic diagram.

FIG. 4 is a device characteristic diagram.

[Explanation of symbols]

1 Anti-vibration rubber body 2 Rubber membrane 3 Partition plate 31, 32 Flow path 4 Rotary valve (valve member) 5 Valve control circuit (valve control means) M engine mount

Claims (1)

[Claims] Claim 1: A device comprising two liquid chambers that are connected to a vibrating body and deform complementary to each other, and these liquid chambers are communicated by two flow paths that generate liquid resonance in vibration regions with different frequencies, and on the high frequency side. A liquid-filled vibration isolator characterized in that a valve member for changing the cross-sectional area of the flow path is provided in a flow path where liquid resonance occurs, and a valve control means is provided for driving the valve member to open and close in response to vibration input.