JPH0689807B2 - Anti-vibration device with liquid - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial field of application) The present invention is applied as an elastic bush, an engine mount, a cab mount, etc., capable of effectively damping low-frequency large-amplitude vibrations, and sufficiently absorbing high-frequency small-amplitude vibrations. The present invention relates to an anti-vibration device containing liquid having excellent durability.

(Prior Art) As a conventional liquid vibration isolator of this type, for example, a highly rigid inner cylinder and an outer cylinder that are concentrically arranged are interconnected by a rubber elastic body, and a rubber is used between these inner and outer cylinders. At the center of the elastic body in the axial direction, there are two liquid chambers that are divided in opposition to each other in the diametrical direction, and in which an incompressible liquid is sealed, and one or more of these liquid chambers are provided. Some have been connected by the throttle passage.

Such an anti-vibration device has a structure in which the liquid in one liquid chamber passes through the throttle passage and the other liquid chamber, especially for low-frequency large-amplitude vibrations (for example, vibrations of around ± 1 mm below 50 Hz). The flow resistance exerted by the throttle passage on the liquid pair as it enters the chamber can convert the kinetic energy of the liquid into thermal energy, resulting in effective damping of vibrations.

However, in such a conventional vibration damping device, when the cross-sectional area and length of the throttle passage that provides communication between both liquid chambers are selected so as to provide sufficient damping of vibration in the low frequency band, , The vibration of a relatively low frequency in the high frequency band causes the closed state of the throttle passage due to the inertial force and frictional force of the liquid in the throttle passage, and as a result, the dynamic spring constant increases sharply. Therefore, there is a problem in that the insulation and the damping of the vibration can hardly be brought about for the higher frequency vibration.

For this reason, a bush type liquid vibration isolator as disclosed in Japanese Patent Laid-Open No. 60-179542 discloses that it can absorb not only low frequency large amplitude vibrations but also high frequency small amplitude vibrations. Is proposed.

This anti-vibration device is provided with two stoppers projecting into the liquid chamber, which are opposed to each other in the diametrical direction, on a metal block body fixed around the inner cylinder, and these stoppers are sandwiched by the inner cylinder. Is provided with protrusions projecting in the right angle direction, and these protrusions are vulcanized and adhered to the rubber sleeves surrounding them, while a rubber movable member that functions as a movable member is provided in the communication hole provided in each protrusion. It is configured by arranging the body.

When transmitting high-frequency, small-amplitude vibrations to the vibration-damping device, the rubber movable body is displaced in the protruding portion based on the pressure difference between the respective liquid chamber pressures, so that the vibrations are effectively absorbed. can do.

(Problems to be Solved by the Invention) However, in the proposed technique, in particular, the protruding portion of the block body surrounding the rubber movable body is vulcanized and adhered to the rubber sleeve surrounding it. However, due to the repeated load acting on the vibration isolator, stress is concentrated on the vulcanized bond relatively early and cracks occur, causing the liquid to leak.

To describe this more concretely, with the load of 40 kg that acts in the direction orthogonal to the axis of the inner and outer cylinders and deforms each liquid chamber in the compression direction and the expansion direction, According to the proposed technology, the number of repeated durability is about 430,000 times when the torsional load that causes relative displacement in the direction of ± 15 ° is applied at a frequency of 3Hz. It has been confirmed that the above-mentioned conventional vibration damping device, which is capable of absorbing the high frequency small amplitude vibration, does not cause any abnormality even after repeating 1.5 million times.

Therefore, the present invention is a liquid-filled vibration damping device that does not cause any abnormality even when subjected to the action of 1.5 million cycles of repeated load, and is capable of sufficiently attenuating low-frequency large-amplitude vibrations and absorbing high-frequency small-amplitude vibrations. I will provide a.

(Means for Solving the Problems) The present invention provides, for example, an inner cylinder and an outer cylinder that are concentrically arranged,
They are interconnected by an elastic body made of rubber, a rubber-like elastic material, a synthetic resin or the like, or mainly composed of any of them, and are partitioned at a circumferential direction between these inner and outer cylinders, and In a liquid vibration isolator in which a plurality of liquid chambers filled with incompressible liquid are provided, and these liquid chambers are made to communicate with each other by a throttle passage, in the elastic body, any two Cylindrical casings each having an opening in the liquid chamber are fitted and fixed, and in this cylindrical casing, vibrating members that are displaced by the differential pressure of the liquid chamber pressure are disposed.

(Operation) In this anti-vibration device, when low-frequency large-amplitude vibration is transmitted to it, one liquid chamber is compressed and the other liquid chamber is expanded based on the action of external force. The fluid in one liquid chamber flows into the other liquid chamber through the throttle passage under the displacement of the vibrating member, so that the action of the throttle passage provides sufficiently effective damping of the vibration.

Further, when high-frequency small-amplitude vibrations are transmitted to this vibration isolator, when the throttle passage is closed, the flow of liquid through the throttle passage becomes substantially impossible, but Since the vibrating member is displaced in the cylindrical casing according to the increase / decrease in the room pressure, the increase in the liquid room pressure is effectively prevented, and the increase in the dynamic spring constant due to the vibration is sufficiently suppressed. Will be.

Further, in this vibration isolator, the tubular casing having the vibrating member inside is fitted and fixed there under the pressure-type deformation of the elastic body, and since the casing and the elastic body are in a non-bonded state, Even if the inner and outer cylinders undergo a large relative displacement in the radial and circumferential directions, the deformation of the elastic body due to the cylindrical casing is limited, in other words, stress concentration on the casing peripheral surface due to the deformation of the elastic body is eliminated. As a result, the durability of the elastic body and thus the device can be improved to three times or more that of the above-mentioned proposed technique.

(Example) Hereinafter, the present invention will be described based on illustrated examples.

FIG. 1 is a sectional view showing an embodiment of the present invention.
Reference numerals 1 and 2 respectively denote an inner cylinder and an outer cylinder made of a rigid material such as metal or synthetic resin. Here, the inner and outer cylinders 1 and 2 arranged concentrically are interconnected by an elastic body 3.

Here, a substantially cylindrical elastic body 3 that can be mainly composed of rubber, a rubber elastic body, a rigid resin, or the like.
Is an intermediate ring 3 that is axially separated from the outer circumference of the intermediate ring 3.
The elastic body 3 has its inner peripheral surface joined to the inner cylinder 1 by vulcanization or the like, while the elastic body 3 has intermediate rings 3a, 3a.
By fixing the outer cylinder 2 to the outer periphery of a through the O-rings 4, 4 by caulking or the like, the inner and outer cylinders 1, 2 are interconnected.

Further, here, the inner and outer cylinders 1 and 2 are partitioned at the central position of the elastic body 3 in the axial direction so as to be opposed to each other in the diametrical direction, and
Two liquid chambers 5 filled with a liquid having the required kinematic viscosity,
6 are provided, and these liquid chambers 5 and 6 are joined or fitted and fixed to the outer peripheral surface of the elastic body 3 between the intermediate rings 3a and 3a, and the circumferential groove of the rigid arc-shaped piece 7 and the outer cylinder 2 are provided. And the inner peripheral surface of the two are communicated with each other by a single throttle passage 8. Here, the length of the throttle passage 8 can be appropriately changed by making it meander in the axial direction of the inner and outer cylinders 1 and 2.

Further, in the figure, 9 and 10 indicate stoppers which are projected outward in the radial direction into the respective liquid chambers. For example, as shown in the figure, a rigid block is fitted and fixed to a required position of the inner cylinder 1. These stoppers 9 and 10, which can be configured as described above, preferably function to prevent excessive relative displacement of the inner and outer cylinders 1 and 2 under the buffering action of the elastic coating formed on the tip surfaces thereof.

The stoppers 9 and 10 can also be configured by projecting a rigid member into the liquid chambers 5 and 6 from the outer cylinder side toward the inner cylinder side.

Further, in the illustrated example, a cylindrical casing 11 extending in the circumferential direction along the inner peripheral surface of the outer cylinder 2 is fitted and fixed in the elastic body 3 at a position opposed to the throttle passage 8 in the diametrical direction, The tubular casing 11 is opened in each of the liquid chambers 5 and 6, and a vibrating member 12 that bends along the shape of the tubular casing 11 is arranged in the casing so as to be displaceable in the circumferential direction of the outer cylinder 2. Here, it is preferable that the vibrating member 12 made of a synthetic resin or other low specific gravity material has the liquid chambers 5 and 6 respectively.
The pressure receiving portions 12a and 12b having a substantially T-shaped cross-section in the lengthwise direction are provided at the protruding end portions of the pressure receiving portions 12a and 12b. Further, if the cross-sectional area of the vibrating member 12 is set to be considerably larger than that of the throttle passage 8 that contributes to damping of vibration in a required low frequency band, clogging of the vibrating member will be slowed down, and a low dynamic spring constant will be caused. Is preferable in achieving a high frequency band.

Here, assembling the vibrating member 12 into the tubular casing 11 is, for example, as shown in FIG. 2, a frame 11a made of synthetic resin or metal having a predetermined length and having a substantially channel shape. It can be performed by inserting the vibrating member 12 into the inside and then closing the open wall portion of the frame body 11a by the side wall member 11b also made of synthetic resin or metal, and assembled in this way. Tubular casing
11 and the vibration member 12 into the outer peripheral groove provided in the elastic body 3,
The tubular casing 11 is fixed to the elastic body 3 by being fitted under compression deformation of the elastic body 3 around the outer peripheral groove thereof.

In the embodiment described above, it is possible to form the throttle passage 8 inside the vibrating member 12 or inside the stoppers 9 and 10. In such a case, the rigid arc-shaped piece 7 is omitted and the elastic body 3 is omitted. The outer peripheral surface of the vibrating member 12 can be directly brought into close contact with the inner peripheral surface of the outer cylinder 2, and the vibrating member 12 can be formed on the surfaces facing each other as shown in FIG. 8b
Can be provided by mutual joining of the half members 12c and 12d.

In the vibration isolator configured in this manner, by transmitting low-frequency large-amplitude vibration to the inner cylinder 1 or the outer cylinder 2, it is expanded to one of the liquid chambers, in the compression direction thereof, and to the other liquid chamber. When an external force in each direction acts, the liquid in the compressed liquid chamber flows into the other liquid chamber through one throttle passage 8 while the vibrating member 12 is displaced. This causes the flowing liquid to be converted by its restrictor passages 8 into kinetic energy that it has, into thermal energy, resulting in a sufficiently effective damping of vibrations.

On the other hand, when the high-frequency small-amplitude vibration is transmitted to the vibration isolator so that the throttle passage 8 is closed, the vibrating member 12 is tubular in response to the increasing and decreasing tendency of the liquid chamber pressure. Since the displacement in the casing 11 is made smooth and the increase in the liquid chamber pressure is effectively suppressed, the increase in the dynamic spring constant is sufficiently prevented.

Further, in this vibration isolator, the tubular casing 11 is provided with the elastic body 3
Since the elastic body 3 is not adhered to the tubular casing 11, the elastic body 3 is not restricted by the tubular casing 11, and in other words, the stress is concentrated not only on the inside but also on the portion adjacent to the tubular casing 11. Instead, it can be elastically deformed freely, which leads to a significant improvement in the durability of the elastic body 3.

By the way, in the device of the illustrated example, a load of 40 kg that acts in a direction orthogonal to the axis of the inner and outer cylinders 1 and 2 to deform the respective liquid chambers 5 and 6 in the compression direction and the expansion direction is applied. When a torsional load that relatively displaces the cylinders 1 and 2 in the circumferential direction by ± 15 ° is applied at a frequency of 3 Hz, 150
It has been confirmed that no abnormality occurs even under repeated loads of 10,000 times. Therefore, the durability of the vibration isolator against repeated load reaches three times or more that of the vibration isolator disclosed in Japanese Patent Laid-Open No. 60-179542.

FIG. 4 is a sectional view showing another embodiment of the present invention. In this example, the cylindrical casings 11 and 11 are provided on the outer peripheral surface of the elastic body 3 at two locations opposed to each other in the diametrical direction. Then, the vibrating member 12 is displaceably fitted in each of the casings 11, and the throttle passage 8 is formed in the stoppers 9 and 10.

Although not shown, here, the throttle passage 8 extending from the tip of one stopper 9 to the tip of the other stopper 10 through the circumference of the inner cylinder 1 is orthogonal to the cross section shown in the drawing or its surface. It can be bent in-plane as required, and the throttle passage 8 can be formed in at least one of the vibrating members.

According to this example, the total cross-sectional area of the vibrating member 12 can be made sufficiently large, so that the vibrating member 12 is less likely to be clogged and a low dynamic spring constant can be maintained up to a high frequency band. The other operations of the illustrated device are the same as those described above.

Although the present invention has been described above based on the illustrated example, it is also possible to form the throttle passage 8 inside the main body portion of the elastic body 3 made of rubber or the like, and in the illustrated example, the outer periphery of the elastic body 3. One or two casings 11 fitted and fixed on the surface can be fitted and fixed in the through hole provided in the elastic body 3 between the outer peripheral surface of the elastic body 3 and the stopper rigid block. In such a case, the outer peripheral surface of the elastic body 3 may be brought into close contact with the inner peripheral surface of the outer cylinder 2 directly, or the inner peripheral surface of an intermediate cylinder (not shown) may be brought into contact with the intermediate rings 3a, 3a. It is also possible to let. Further, in the illustrated example, the number of the liquid chambers, which is two, may be three or more, and the displacement direction of the vibrating member 12 may be the vertical direction in the illustrated example or another required direction.

(Effect of the Invention) Therefore, according to the present invention, the low-frequency large-amplitude vibration transmitted to the anti-vibration device can be effectively damped under the action of the throttle passage, and the high-frequency small-amplitude vibration can be transmitted. It is possible to sufficiently suppress the increase of the dynamic spring constant caused by the above, and further, by making the cylindrical casing non-bonded to the elastic body, it is possible to remarkably improve the durability of the vibration isolator. .

[Brief description of drawings]

1 is a sectional view showing an embodiment of the present invention, FIG. 2 is an exploded perspective view showing an example of assembling a vibrating member to a cylindrical casing, FIG. 3 is an exploded perspective view illustrating the vibrating member, FIG. 4 is a sectional view showing another embodiment of the present invention. 1 ... Inner cylinder, 2 ... Outer cylinder, 3 ... Elastic body, 5,6 ... Liquid chamber, 8 ... Throttle passage, 9,10 ... Stopper, 11 ... Cylindrical casing, 12 ... Vibration member

Claims (1)

[Claims] 1. An inner cylinder and an outer cylinder, an elastic body interconnecting these inner and outer cylinders, and a plurality of liquid chambers which are partitioned in the circumferential direction between the inner and outer cylinders and in which liquid is sealed. And a liquid-filled vibration damping device comprising a throttle passage that brings these liquid chambers into communication with each other, in the elastic body, a tubular casing that opens in any two liquid chambers is fitted and fixed, and An anti-vibration device filled with liquid, in which a vibrating member that is displaced by a pressure difference between respective liquid chamber pressures is arranged in a tubular casing.