JPS60192141A - Liquid-sealed vibration proof device - Google Patents

Abstract

PURPOSE:To effectively absorb and reduce high-frequency vibration by forming a part of the wall of a fluid chamber by a piezo-electric ceramic plate and vibrating the piezo-electric ceramic plate according to vibration to relieve a change of internal pressure in the fluid chamber. CONSTITUTION:A bent round piezo-electric ceramic plate 7 is interposed in parallel between an upper plate 2 of a vibration-proof device and a cover 6. According to the running condition of a car, the oscillation frequency of an engine changes. When the piezo-electric ceramic plate is bent and vibrated in accord with the oscillation cycle, a change of the internal pressure in the first fluid chamber A is sufficiently relieved to absorb and reduce the engine oscillation quickly. If the oscillation of a large amplitude is input, sealed fluid flows through a throttle hole 41 to damp the oscillation.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a liquid-filled vibration isolator used in a vehicle engine mount or the like.

[Prior art]

The above-mentioned vibration isolating device has first and second chamber walls each having a deformable chamber wall.
These fluid chambers are communicated with each other through a throttle hole, and at least one of them is connected to a vibrating body, so that the sealing fluid can be flowed into the throttle hole at high speed by increasing the pressure in the chamber due to the deformation of the fluid chamber due to vibration input. By allowing the flow to flow, especially low frequency large amplitude vibrations can be effectively damped.

By the way, the frequency of the engine changes over a wide range depending on the driving condition of the vehicle, and for high-frequency vibrations with small amplitudes, rather than damping the vibrations, it is better to alleviate the changes in indoor pressure caused by the deformation of the fluid chamber. It is desirable to absorb vibrations. Therefore, a part of the empty wall of the fluid chamber connected to the vibrator was
It has been proposed to use a movable wall that can move in the direction of absorbing indoor pressure and alleviating it. The problem was that it was not carried out effectively.

[Purpose of the invention]

SUMMARY OF THE INVENTION In view of the above problems, it is an object of the present invention to provide a liquid-filled vibration isolator that can absorb and reduce high frequency vibrations very effectively.

[Structure of the invention]

That is, in the vibration isolating device of the present invention, a part of the chamber wall of the fluid chamber is constituted by a piezoelectric ceramic plate, and is provided with an energizing means for energizing the piezoelectric ceramic plate in accordance with the vibration input cycle.

In the high frequency vibration range, the piezoelectric ceramic plate is caused to vibrate in one plane by matching the vibration period of the vibrating body so as to alleviate changes in the internal pressure of the fluid chamber, thereby absorbing the high frequency vibration.

[Embodiment 1] In FIGS. 1 and 2, 1 is a cylindrical thick rubber elastic wall, and the upper and lower openings are covered with a top plate 2115 and a bottom plate 3, respectively. Then, the elastic wall 1 and the upper plate 2
In the space formed by J5 and the bottom plate 3, a partition plate 4 whose center part is bent into a chevron shape and a thin rubber elastic sheet 5 are arranged, and the peripheral edge of these sheets is between the bottom plate 3 and the elastic wall 1. It is clamped and fixed. 1. A first fluid chamber A having the elastic wall 1 as a chamber wall and a second fluid chamber B having the elastic sheet 5 as a chamber wall are formed in the device by the partition plate 4. In addition,
A throttle hole 41 is formed in the center of the partition plate 4 to allow the fluid chambers A and B to communicate with each other.

The upper plate 2 has a thin central portion 21 that protrudes inward with a curved surface, and a thick outer circumferential portion 22 of the elastic wall 1.
It is joined to. A cover plate 6 having a curved surface of the same shape is attached to the upper plate 2 from above with a predetermined gap maintained therebetween. A circular piezoelectric ceramic plate 7 curved and parallel to the upper plate 2 and the cover plate 60 is arranged between the upper plate 2 and the cover plate 60. The piezoelectric ceramic plate 7 has its peripheral edge liquid-tightly embedded in a resin provided in the stepped inner circumferential portion of the upper plate 2, and constitutes a chamber wall of the first fluid chamber A. Electrodes 71.72 are formed on the upper and lower surfaces of the center of the ceramic plate 7, and each electrode 71.72
is connected to a power supply line 8 from an external current supply means at the circumferential end of the helical plate 7 by a lead portion of the circuit.

Note that the piezoelectric ceramic plate 7 of the upper plate 2 and the cover plate 6
The surface facing the ceramic plate 7 is covered with a circuit rubber sheet to prevent damage to the ceramic plate 7 due to contact, and this portion is also provided with a large number of liquid flow holes 211 and air flow holes 61, respectively.

When electricity is applied from the electricity supply means through the power supply line 8, the portion of the piezoelectric ceramic plate 7 existing between the electricity I#A 71 and 72 expands and contracts depending on whether the electricity is applied in the forward or reverse direction. , the first fluid chamber A expands or contracts by vibrating in the vertical direction.

As the piezoelectric ceramic plate, a very common lead titanate type or zirconate lead titanate type can be used.

The engine is mounted and fixed by inserting bolts into punch holes 22a provided in the outer circumference 22 of the top plate 2, and the main body of the apparatus is fixed to the vehicle body frame by bolts 3a provided upright on the bottom plate 3.

When the engine is started, the piezoelectric ceramic plate 7 is not energized.

If cranking vibration of large amplitude is input in this state, the rubber elastic body wall 1 will be greatly deformed and the internal pressure of the first fluid chamber Δ will change. The ceramic plate 7 is bent vertically in response to internal pressure, but the bending range is limited by the upper plate 2 and cover plate 6, so that the internal pressure cannot be alleviated. Therefore, a high internal pressure is generated in the fluid EfA, and the sealing fluid flows through the throttle hole 41 at high speed, resulting in large vibration damping.

After the engine is started, the engine vibration frequency changes over a wide range depending on the running condition of the vehicle, but the vibration width becomes much smaller than at the time of starting. Therefore, in the present invention, the piezoelectric ceramic plate 7 is energized in the forward and reverse directions using the energizing means to match the imaging period of the engine, thereby causing it to vibrate in one plane.

Since the engine vibration amplitude in this case is small as mentioned above,
Due to the ceramic plate 7 vibrating in the gap between the upper plate 2 and the cover plate 6 at the same frequency as the engine vibration, changes in the internal pressure of the first fluid chamber Δ are sufficiently alleviated, and the engine vibration is quickly absorbed. Since the ceramic plate 7 itself is actively vibrating, it can sufficiently follow the engine vibration even if the frequency is high.Thereby, high frequency vibrations can be effectively absorbed and reduced.

If a shake vibration or the like having a width of J length is input while the vehicle is running, the internal pressure of the first fluid chamber △ is alleviated by the piezoelectric ceramic plate 7 whose bending range is regulated by the upper plate 2 cover plate 6. First, the sealing fluid flows through the throttle hole 41 and damps the cranking vibrations at the time of starting.

[Embodiment 2] FIG. 2 shows an example in which the piezoelectric ceramic plate 7 is used as a partition plate that partitions the first and second fluids uA and B.

That is, in the figure, the support plate 91 and the stopper plate 9
2 has the same shape with a thin center portion and a curved surface protruding upward, and the thick outer peripheral portion is laminated to form the side wall of the device. A piezoelectric ceramic plate 7 is disposed between the support plate 91 and the stopper plate 92.

A throttle hole 73 is formed in the center of the ceramic plate 7, and its periphery is liquid-tightly embedded in the resin provided on the stepped part of the inner circumference of the stopper plate 92, thereby allowing the first and second Fluid chambers A and B are defined. Note that the support plate 91
And the stopper plate 92 has a large number of liquid flow holes 911 and 92.
1 is provided. The engine is bolt 2 installed vertically on the upper plate 2
The main body of the device is fixed to the vehicle body frame by inserting bolts into the holes 91a of the support plate 91.

When low-frequency, large-amplitude vibrations from the engine are input, the support plate 9
The internal pressure of the first fluid chamber A is not relieved by the ceramic plate 7 whose deformation range is regulated by the ceramic plate 1 and the stopper plate 92, and the sealing fluid passes through the throttle hole 73, resulting in large vibration damping. On the other hand, with respect to high-frequency, small-amplitude vibrations, changes in the internal pressure of the fluid chamber A are alleviated by the ceramic plate 7, which vibrates with the same vibration period, thereby absorbing the vibrations.

Such a structure also provides the same effects as the above embodiment. Note that the aperture hole does not necessarily need to be provided in the ceramic plate, and may be formed, for example, in the side wall.

(Embodiment 3) FIGS. 4 and 5 show an example in which the present invention is applied to a vibration isolation system that effectively absorbs idling vibrations of relatively large amplitude.

In the figure, inside the device are first and second fluids W, which have empty walls of rubber elastic walls 11 and 12 that are integrally connected by a mouth-shaped outer plate 101 and are alternately deformed by a vibrating saw.
A and B are formed. The partition plate 4 that partitions both the fluids 1ASB is connected at its peripheral edge to the cylindrical side wall 9 by a rubber sheet 44, and can move vertically while maintaining a horizontal posture. The partition plate 4 is made up of curved plates 42 and 43 of the same shape having a large number of liquid flow holes 421 and 431, which are placed opposite each other at a predetermined distance, and a piezoelectric ceramic plate 7 is disposed between the two plates 42 and 43. be. This piezoelectric ceramic plate 7 has both fluid 'J'
A throttle hole 73 communicating with A1B is formed. The thick peripheral edge of the ceramic plate 7 is sandwiched between the plate members 42 and 43. An electromagnetic coil 10 for attracting and fixing the partition plate 4 is embedded in the side wall 9. In addition, the engine is Pol I
2a is placed and fixed on the upper plate 2, and the main body of the device is fixed to the vehicle body frame by inserting a bolt into the hole 9a.

When starting the engine and running, the electromagnetic coil 10 is energized to fix the partition plate 4. If large-amplitude vibrations such as cranking vibrations and shaking vibrations are input in this state, the internal pressures in both fluid chambers A and B cannot be alleviated due to the deformation of the ceramic plate 7, and the sealing fluid flows through the throttle hole 73, resulting in large vibrations. Causes attenuation. On the other hand, when high-frequency, small-amplitude vibrations are input, the internal pressures of both fluid chambers A and B are kept sufficiently low by the ceramic plate 7, which vibrates at the same vibration period, thereby effectively absorbing the high-frequency vibrations. .

At the time of idling photographing input, the energization to the electromagnetic coil 10 is stopped, and the partition plate 4 is made freely movable in order to relieve the internal pressure of both fluid chambers A and s. Thereby, idling vibrations with relatively large amplitude can be absorbed.

In each of the above embodiments, only the vibration period of the piezoelectric ceramic plate was made to match the engine vibration, but the amplitude of the engine vibration generally becomes smaller as the frequency becomes higher. Therefore, if the applied voltage is lowered accordingly and the amplitude of the ceramic plate is controlled within the required range, power consumption can be reduced and vibration followability can be improved.

Further, if the thickness of the piezoelectric ceramic plate is made sufficiently thick so that it does not undergo curved deformation due to changes in internal pressure upon input of large-amplitude vibrations, there is no particular need for a member to restrict the deformation of the ceramic plate.

〔Effect of the invention〕

As described above, in the liquid-filled vibration isolator of the present invention, a part of the fluid chamber is constituted by a piezoelectric ceramic plate, and in a high frequency imaging range, the ceramic plate is used as a vibrating body to alleviate changes in the internal pressure of the fluid chamber. High frequency vibrations can be effectively absorbed and reduced by causing the curved vibration to match the vibration period.

[Brief explanation of drawings]

1 and 2 show a first embodiment of the present invention, FIG. 1 is an overall sectional view of the device, a sectional view taken along line I-I in FIG. 2, and FIG. 3 shows a second embodiment of the present invention; FIG.
The figure shows a third embodiment of the present invention, and FIG. 4 is a sectional view of the entire device, and FIG.
The figure is a plan view of the device viewed from above. 1.5... Chamber wall 41.73... Throttle hole 7... Piezoelectric ceramic plate 8... Power supply lines A, B...・Fluid chamber Figure 1 Figure 2 LI

Claims (1)

[Claims] It has first and second fluid chambers made of hollow walls that are deformed by vibration input and communicated through a throttle hole, and at least one of the fluid chambers is connected to a vibrating body so that the fluid chamber deforms as the fluid chamber deforms. In a liquid-filled vibration isolator that attenuates low-frequency vibration by causing fluid to flow through both fluid spaces through a constriction due to changes in internal pressure, a part of the empty wall of the fluid chamber connected to the vibrating body is made of a piezoelectric ceramic plate. At the same time, an energizing means is provided for energizing the piezoelectric ceramic plate in accordance with the vibration period of the vibrating body, and the piezoelectric ceramic plate is connected to the piezoelectric ceramic plate in accordance with the vibration period of the vibrating body so as to alleviate changes in the internal pressure of the fluid chamber in the high frequency vibration range. 1. A liquid-filled vibration isolating device characterized by being made to vibrate in one plane by matching the above.