JPH03181634A - Liquid sealed vibration isolator - Google Patents

Abstract

PURPOSE:To excellently damp low frequency vibration and absorb high frequency vibration in a large property variable range by providing, in a sub liquid chamber, a valve body and valve drive means for operating the valve body according to a vibration input so as to open and close the opening of an auxiliary liquid chamber and a short throttle passageway simultaneously. CONSTITUTION:A liquid sealed vibration isolator is provided with a main liquid chamber A where a thick vibrationproof rubber 1 for supporting a vibration serves as a chamber wall, and a sub liquid chamber B where a freely deformable rubber sheet 2 functions as a chamber wall. The liquid chambers A and B are partitioned by a partition wall 3. Inside the partition wall 3, there are provided an auxiliary liquid chamber C which is partitioned from the main liquid chamber A by a movable wall 31 capable of moving within a predetermined limit in such a direction as to absorb a change of inner pressure of the main liquid chamber A and intercommunicated with the sub liquid chamber B through an opening 32, and long and short throttle passageways 34, 33 for connecting the main liquid chamber A to the sub liquid chamber B. Furthermore, inside the sub liquid chamber B, there are provided a valve body 4, and valve drive means 5 for operating the valve body 4 according to an vibration input so as to open and close the opening 32 of the auxiliary liquid chamber C and the short throttle passageway 33 simultaneously.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a liquid-filled vibration isolator, and particularly to a liquid-filled vibration isolator whose characteristics can be significantly changed to effectively prevent vibration transmission over a wide range.

[Prior Art] Liquid-filled vibration isolators are devices that can effectively damp particularly low-frequency, large-amplitude vibrations by forcing the filled liquid to flow through a constricted flow path, and are increasingly being used in vehicle engine mounts, etc. . Various attempts have been made to make the characteristics of such a liquid-filled vibration isolator variable to accommodate a wide range of vibration inputs.
47817), or opening and closing the openings of the partition wall that partitions the liquid chamber as appropriate (Japanese Patent Laid-Open No. 61-55427).
Structures such as the following have been proposed.

[Problems to be Solved by the Invention] However, all of the conventional structures described above still have a problem in that the characteristic variable width is not sufficient.

SUMMARY OF THE INVENTION Therefore, the present invention aims to solve this problem, and aims to provide a liquid-filled vibration isolator that has a wide range of variable characteristics and can effectively damp both low-frequency vibrations and absorb high-frequency vibrations. .

[Means for Solving the Problems] To explain the present invention in detail, the liquid-filled vibration isolator includes a main liquid chamber A whose chamber wall is a thick vibration-proof rubber body 1 that supports a vibrating body, and a freely deformable The main liquid chamber A has a sub-liquid chamber B having a rubber sheet 2 as a chamber wall, and these liquid chambers are divided by a partition wall 3, and inside the partition wall 3, changes in the internal pressure of the main liquid chamber A are absorbed. An auxiliary liquid chamber C1 is separated from the main liquid chamber A by a movable wall 31 that can be moved within a certain direction in a certain direction, and communicates with the auxiliary liquid chamber B through an opening 32, and connects the main liquid chamber A and the auxiliary liquid chamber B. A long throttle channel 34 and a short throttle channel 33 are provided, and a valve body 4 is provided in the auxiliary liquid chamber B. The valve body 4 is actuated in response to vibration input to open the auxiliary liquid chamber C. 32 and a short throttle flow path 33 are provided with a valve driving means 5 that opens and closes them simultaneously.

[Function] In the liquid-filled vibration damping device having the above configuration, the opening 32 of the auxiliary liquid chamber C and the short throttle channel 33 are closed by the valve body 4 when the engine is started. The vibration isolating rubber body 1 deforms due to vibration input, and the internal pressure of the main liquid chamber A increases. Auxiliary liquid chamber C is opening 3
2 is closed and in an airtight state, the movable wall 31 cannot move, and as a result, the internal pressure of the main liquid chamber A rises sufficiently to increase the dynamic spring constant of the device. At this time, the sealed liquid flows from the main liquid chamber A through the long throttle channel 34 to the sub-liquid chamber B, and due to the liquid resonance in the throttle channel 34, the device has a large damping coefficient in a sufficiently low frequency range. . As a result, cranking vibrations and the like associated with starting the engine can be effectively damped and reduced.

When the vehicle is running, the valve body 4 is operated to open the opening 32 of the auxiliary liquid chamber C and the short throttle channel 33. By opening the auxiliary liquid chamber C to the auxiliary liquid chamber B, the movable wall 31 can move within a certain limit, and even if high-frequency muffled sound vibrations are input while the vehicle is running, the main liquid Changes in the internal pressure of the chamber A are absorbed by the movement of the movable wall 31, the spring constant of the device becomes smaller, and muffled sound vibrations are well absorbed and reduced.

In addition, in response to engine shake vibration input while the vehicle is running, the sealed liquid flows through the short throttle flow path 33 and causes liquid resonance, so that the damping coefficient of the device is in the higher low frequency region. It exhibits a large value in the shake vibration range, and effectively damps and reduces shake vibration.

[Example] In FIG. 1, the vibration-proof rubber body l is a thick-walled container body that opens downward, the top plate 6 is joined to the top surface, and the upper end of the cylindrical side plate 7 is joined to the opening edge. has been done.

The interior of the side plate 7 is partitioned into upper and lower sections by a partition wall 3, with a main liquid chamber A formed in the upper part having the vibration isolating rubber body 1 as a chamber wall, and a sub liquid chamber B having the rubber sheet 2 as a chamber wall in the lower part. It is formed.

The partition wall 3 is constructed by stacking ring plates 35 and 36 one on top of the other, and the upper ring plate 35 has a short throttle channel 33 formed approximately halfway around its interior, one end of which communicates with the main liquid chamber A.
Figure 2). The center opening of the ring plate 35 is sealed with a rubber movable wall 31 that can be deformed within a certain limit in the vertical direction, and an auxiliary liquid chamber C is formed below the movable wall 31. This auxiliary liquid chamber C communicates with the auxiliary liquid chamber B through the center opening 32 of the lower ring plate 36.

Inside the lower ring plate 36, a flow passage communicating with the short throttle passage 33 and constituting a long throttle passage 34 is formed approximately halfway around the circumference and opens into the sub-liquid chamber B. The throttle channel 33 communicates with the sub-liquid chamber B through a through hole 37 at its terminal end.

A disk-shaped valve body 4 is disposed in the sub-liquid chamber B, and the valve body 4 is fixed to the tip of a valve drive frame 5 that penetrates the rubber sheet 2 in a liquid-tight manner, and is movable up and down. However, in the raised position, as shown in FIG. 1, its outer peripheral surface abuts against the lower surface of the lower ring plate 36 to close the opening 32 and the through hole 37. A vent hole 41 is formed in the valve body 4 in correspondence with the outlet opening of the long throttle flow path 34, so that the long throttle flow i34 always connects both liquid chambers A and B.

At the lower end of the side plate 7 is a container-shaped bottom plate 8 that opens upward.
The partition wall 3 and the outer periphery of the rubber sheet 2 are integrally fixed to the caulked portion. The lower half of the valve drive frame 5 is located inside the bottom plate 8, and the interior of the bottom plate 8 is divided into upper and lower sections by a diaphragm 51 stretched between its outer periphery and the side wall of the bottom plate 8. An air chamber E is formed, and a negative pressure chamber is formed below.

The valve drive rod 5 is connected to a coil spring 52 provided in the negative pressure chamber.
The negative pressure chamber is always urged upward by the vacuum chamber, and atmospheric pressure or negative pressure is supplied to this negative pressure chamber by a simultaneous electromagnetic switching valve via a pipe joint 8 provided on the side surface of the bottom plate 8.

The vehicle engine, which is a vibrating body, is placed on the top plate 6 and fixed with bolts, and the vibration isolator is fixed to the vehicle frame with bolts on the bottom plate 8.

In the liquid-filled vibration isolator having the above structure, the negative pressure chamber is placed in an atmospheric state when the engine is started. In this state, the valve drive rod 5 is in the upper position shown in the figure due to the biasing force of the coil spring 52, and closes the opening 32 and the through hole 37 of the auxiliary liquid chamber C. When cranking vibration is input here, the vibration isolating rubber body (2) deforms and the internal pressure of the main liquid chamber A increases. Since the auxiliary liquid chamber C is in a sealed state with the opening 32 closed, the movable wall 31
cannot be deformed and moved, and as a result, the internal pressure of the main liquid chamber A rises sufficiently to increase the dynamic spring constant of the device. This is shown by line X in FIGS. 3 and 4.

At this time, the long throttle channel 3 in which the short throttle channel 33 is extended
4, the sealed liquid flows toward the sub-liquid chamber B, and the device has a large damping coefficient in a sufficiently low frequency range due to the liquid resonance in the throttle channel 34 (line y in FIG. 3). As a result, cranking vibrations associated with engine starting can be effectively damped and reduced.

When the vehicle is running, negative pressure is supplied to the negative pressure chamber.

As a result, the valve drive rod moves downward against the spring force of the coil spring, and as a result, the opening 32 of the auxiliary liquid chamber C
The through hole 37 is opened. By opening the auxiliary liquid chamber C to the auxiliary liquid chamber B, the movable wall 31 can deform and move within a certain limit, and even if high-frequency muffled sound vibrations are input while the vehicle is running, the main Changes in the internal pressure of the liquid chamber A are absorbed by the movement of the movable wall 31, and the spring constant of the device becomes smaller (line xi in Figure 4), so that muffled sound vibrations are well absorbed and reduced.

In response to large-amplitude engine shake vibrations input while the vehicle is running, the sealed liquid flows through the short throttle flow path 33 to the sub-liquid chamber B through the through hole 37, causing liquid resonance, which reduces the damping coefficient of the device. shows a large value in the shake vibration region in the higher region of low frequencies (line y- in the third diagram), effectively damping and reducing shake vibration.

[Effects of the Invention] As described above, the liquid-filled vibration damping device of the present invention has a structure in which a valve body for opening and closing the auxiliary liquid chamber opening and the throttle channel opening behind the movable wall significantly changes the device characteristics. It is possible to better reduce various vibrations ranging from low frequencies to high frequencies.

[Brief explanation of drawings]

FIG. 1 is an overall sectional view of a liquid-filled vibration isolator according to an embodiment of the present invention, FIG. 2 is a perspective view of a partition wall, and FIGS.
The figure is a diagram showing the frequency characteristics of the device. ■... Vibration-proof rubber body 2... Rubber sheet 3... Partition wall 31... Movable wall 32... Opening 33... Short throttle channel 34... Long throttle channel 4...・Valve body 5...Valve drive rod (valve drive means) A...Main liquid chamber B...Sub-liquid chamber C...Auxiliary liquid chamber D...Negative pressure chamber E...Atmospheric chamber No. Figure 1 Figure 2 Figure 3 Frequency 30 H, r

Claims (1)

[Claims] It has a main liquid chamber whose chamber wall is a thick vibration-proof rubber body that supports the vibrating body, and a sub-liquid chamber whose chamber wall is a freely deformable rubber sheet, and these liquid chambers are divided by a partition wall. Additionally, within the partition wall, there is an auxiliary liquid that is separated from the main liquid chamber by a movable wall that can move within a certain limit in the direction of absorbing changes in the internal pressure of the main liquid chamber, and that communicates with the auxiliary liquid chamber through an opening. A chamber, and a throttle flow path of different length connecting the main liquid chamber and the sub-liquid chamber are provided, and the sub-liquid chamber includes a valve body and the auxiliary liquid chamber which is actuated in response to vibration input. A liquid-filled vibration isolator characterized by being provided with a valve driving means for simultaneously opening and closing an opening of a liquid chamber and a short throttle channel.