JPH0960687A - Liquid-filled bush - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a liquid-filled bush which has an orifice for damping low frequency vibration and the second orifice for absorbing and controlling high frequency vibration whose orifice characteristic is made variable and thus can absorb and control high frequency vibration in the wide range of frequency. SOLUTION: The outer mounting part 3 is connected to the outer periphery of an inner mounting part 1 via elastic body 7 and a plurality of liquid rooms 8, 9 partitioned by the elastic body 7 communicate with each other via the first orifice 10. A stopper disposed in the liquid room 9 and projecting in the direction of vibration input is provided on the inner mounting part 1 and a gap adjusting member 13 opposite to the stopper is provided on an outer mounting part 3 and a gap 14 between the stopper and the adjusting member 13 forms the second orifice 15. The gap adjusting member 13 can be moved to and from the stopper, whereby the orifice characteristic of the second orifice 15 is made variable.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid-filled bush used as an anti-vibration device or anti-vibration support device in an automobile or the like. The liquid-filled bush according to the present invention is frequently used as an engine mount for automobiles.

[0002]

2. Description of the Related Art Conventionally, an outer mounting portion is connected to an outer peripheral side of an inner mounting portion via an elastic body made of a rubber-like elastic material, and a plurality of liquid chambers partitioned by the elastic body are arranged via orifices. There is known a liquid-filled type bush that communicates with each other and seals the working fluid in the liquid chamber. However, in the conventional liquid-filled type bush, a single orifice for communicating a plurality of liquid chambers with each other is provided. Not too much. Therefore, when this orifice is set to damp low-frequency vibration, high-frequency vibration cannot be absorbed and suppressed, whereas both low-frequency vibration and high-frequency vibration cannot be absorbed and suppressed. A possible product is sought. Further, as disclosed in Japanese Patent Publication No. 5-55739, a liquid-filled type bush provided with a high-frequency device for absorbing and suppressing high-frequency vibration has been developed. Since the resonance frequency is constant and invariable for each product, there is a problem that it is not possible to absorb and suppress high-frequency vibration of a frequency different from the setting.

[0003]

In view of the above points, the present invention has a second orifice that suppresses absorption of high frequency vibration in addition to an orifice that attenuates low frequency vibration, and the orifice characteristics of this second orifice are variable. In view of the above, it is an object of the present invention to provide a liquid-sealed bush capable of absorbing and suppressing high-frequency vibrations over a wide frequency range.

[0004]

In order to achieve the above object, in the liquid-filled type bush of the present invention, the outer mounting portion is connected to the outer peripheral side of the inner mounting portion via an elastic body made of a rubber-like elastic material. A plurality of liquid chambers partitioned by the elastic body are communicated with each other through an orifice, and in a liquid-filled type bush in which a working liquid is sealed in the liquid chambers, one liquid chamber is arranged in the inner mounting portion. In addition, a stopper portion protruding in the vibration input direction is provided, a gap adjusting member facing the stopper portion is provided on the outer mounting portion, and a gap between the stopper portion and the gap adjusting member is a second orifice.
The gap adjusting member can be moved forward and backward toward the stopper portion so that the orifice characteristic of the second orifice can be changed.

[0005]

When a low frequency vibration is input to the liquid-filled type bush of the present invention having the above-mentioned structure, an "orifice" is generated.
Damps this, and when high-frequency vibration is input, the "second orifice" absorbs and suppresses this, and the gap adjusting member is capable of advancing and retracting toward the stopper part, and the orifice characteristic of the second orifice is variable. Therefore, it is possible to absorb and suppress high frequency vibrations of different frequencies within this variable range.

[0006]

BEST MODE FOR CARRYING OUT THE INVENTION In order to match the orifice characteristic of the second orifice with the frequency of the input vibration, a sensor, a controller and a driving mechanism are used together with the liquid-filled bush of the present invention. That is, a sensor that measures the input vibration, a controller that determines the optimum size of the gap by the signal input from this sensor, and the displacement amount of the gap adjusting member according to this, and the gap according to the instructions of this controller. And a drive mechanism such as an air cylinder that actually reciprocates the adjustment member.

[0007]

Embodiments of the present invention will now be described with reference to the drawings.

As shown in FIGS. 1 and 2, the case 4 is provided on the outer peripheral side of the inner (inner peripheral side) mounting portion 1 provided with the inner cylinder 2.
An outer (outer peripheral side) mounting portion 3 including an outer cylinder 5 and a bracket 6 is arranged, and the inner cylinder 2 and the case 4 are connected to each other via an elastic body 7 made of a rubber-like elastic material, and the case 4
The outer cylinder 5 integrated with the bracket 6 is fitted on the outer peripheral side of the.

The inner cylinder 2 has a mounting hole 2a and is basically formed in a cylindrical shape.
A pair of stopper portions 2b and 2c, which have a convex shape in the vertical direction in the figure, which is the main vibration input direction, are integrally provided so as to project. In addition to connecting the inner cylinder 2 and the case 4, the elastic body 7 has a first liquid chamber 8 and a second liquid chamber 9 inside the bush.
And a pair of legs (also referred to as rubber legs) arranged in a substantially V shape for these purposes.
7a, a diaphragm portion 7b, and a pair of axial wall portions (also referred to as rubber wall portions) 7c are integrally provided, and further, a coating portion 7d coated on the inner cylinder 2 and stopper portions 2b, 2
Buffer portions 7e, 7f, etc., which are covered at the tip of c, are integrally provided and integrally vulcanized and molded. The case 4 is provided with annular portions 4a and 4b at both axial ends thereof, and the pair of axial annular portions 4a and 4b are denoted by reference numeral 4 in FIG.
A pair of (a left side in FIG. 2) annular portion 2a is integrally connected to each other by a pair of substantially arcuate cross-section constituent portions shown by c, and an orifice is formed inside the square U-shape. 10 is provided, and this orifice 10 serves as the first liquid chamber 8
And the second liquid chamber 9 are communicated with each other, and a working liquid (also referred to as an internal sealing liquid) 11 such as a viscous fluid is sealed in both chambers 8 and 9. Reference numeral 10a is an opening portion of the orifice 10 on the first liquid chamber 8 side, and 10b is an opening portion on the second liquid chamber 9 side. Also, code 1
2 is a currant.

The bracket 6 is provided with an accommodating recess 6a facing the second liquid chamber 9, and the accommodating recess 6a has a piston-like shape facing the stopper portion 2c arranged in the second liquid chamber 9. Gap adjusting member (also referred to as gap adjusting member) 1
3, the gap (also referred to as a gap) 14 between the stopper portion 2c having the tip end portion covered with the buffer portion 7f and the gap adjusting member 13 serves as the second orifice 15, and the gap adjusting member 13 serves as the stopper portion 2c. The second orifice 15 has a variable orifice characteristic. The gap adjusting member 13 is moved back and forth by operating a drive mechanism (also referred to as a drive device) 16 such as an air cylinder housed in the bracket 6, that is, when the operating rod 16a of the drive mechanism 16 projects. The member 13 rises to reduce the size G of the gap 14, and conversely, when the operating rod 16a of the drive mechanism 16 is retracted, the gap adjusting member 13 descends to expand the size G of the gap 14. Reference numeral 17 is a sensor that measures the input vibration, and reference numeral 18 is a controller that determines the optimum size G of the gap 14 by the signal input from the sensor 17 and determines the displacement amount of the gap adjusting member 13 in accordance with this. ,
According to the instruction from the controller 18, the drive mechanism 16
Moves the gap adjusting member 13 back and forth.

The liquid-filled bush having the above structure is
For example, one of the inner mounting portion 1 and the outer mounting portion 3 is mounted on the vehicle body side of the automobile and the other mounting portion is mounted on the engine side to support the vibration isolation of the engine. When the vibration is input, the vibration is effectively damped by the elasticity provided in the leg portion 7a of the elastic body 7 and the flow resistance or the liquid column resonance of the hydraulic fluid 11 flowing through the orifice 10. Further, when a high-frequency, small-amplitude vibration of a predetermined specific frequency is input to the bush, the hydraulic fluid 11 moves in and out of the second orifice 15 to resonate, as shown by the arrow in FIG. The absolute spring constant of the bush is suppressed to a low level, so that this high-frequency, small-amplitude vibration can be effectively absorbed and suppressed. When the hydraulic fluid 11 enters and leaves the second orifice 15, the wall portion 7c of the elastic body 7 repeats expansion and contraction accordingly.

Further, when vibrations of high frequency and small amplitude of different frequencies occur due to changes in vehicle speed or engine speed, etc., the sensor 17 measures the frequency and amplitude, and the controller 18 computes the measured frequency and amplitude. According to the instruction of 18, the drive mechanism 16 raises or lowers the gap adjusting member 13 to change the size G of the gap 14 between the stopper portion 2c and the gap adjusting member 13, and the second orifice 1
The orifice characteristic or resonance frequency of No. 5 is changed to match this vibration. Therefore, in this state, the bush receives the new high-frequency, small-amplitude vibration, and thus the new high-frequency, small-amplitude vibration can be effectively absorbed and suppressed. Therefore, from these facts, it is possible to effectively absorb and suppress vibrations of high frequency and small amplitude over a wide frequency range, and to provide a liquid-filled bush that exhibits excellent damping characteristics or vibration damping performance.

[0013]

The present invention has the following effects.

That is, in the liquid-filled type bush of the present invention having the above-mentioned structure, when low frequency vibration is input to the bush, the "orifice" attenuates it.
When high-frequency vibration is input, the "second orifice" absorbs and suppresses this, and the gap adjusting member is capable of advancing and retracting toward the stopper part, and the orifice characteristics of the second orifice are variable. , Within this variable range,
High frequency vibrations of different frequencies can be absorbed and suppressed. Therefore, from the above, it is possible to provide a liquid-filled bush that can effectively absorb and suppress high-frequency vibrations over a wide frequency range, and that exhibits excellent damping characteristics or vibration damping performance.

[Brief description of drawings]

FIG. 1 is a front sectional view of a liquid-filled bush according to an embodiment of the present invention.

FIG. 2 is a side sectional view of the liquid-filled bush.

[Explanation of symbols]

 1 Inner mounting part 2 Inner cylinder 2a Mounting holes 2b, 2c Stopper part 3 Outer mounting part 4 Case 5 Outer cylinder 6 Bracket 6a Housing recess 7 Elastic body 7a Leg 7b Diaphragm 7c Wall 7d Cover 7e, 7f Buffer Part 8 1st liquid chamber 9 2nd liquid chamber 10 Orifices 10a, 10b Opening part 11 Working fluid 12 Currant part 13 Gap adjusting member 14 Gap 15 Second orifice 16 Drive mechanism 16a Operating rod 17 Sensor 18 Controller

Claims (1)

[Claims] 1. An outer mounting portion (3) is connected to an outer peripheral side of an inner mounting portion (1) through an elastic body (7) made of a rubber-like elastic material, and is partitioned by the elastic body (7). In the liquid-filled bush in which a plurality of liquid chambers (8) and (9) are communicated with each other through an orifice (10), and the working liquid (11) is sealed in the liquid chambers (8) and (9), the inner mounting is performed. Department (1)
A stopper portion (2c) disposed in the liquid chamber (9) and protruding in the vibration input direction, and a gap adjusting member facing the stopper portion (2c) on the outer mounting portion (3). (13) is provided, the gap (14) between the stopper portion (2c) and the gap adjusting member (13) is the second orifice (15), and the gap adjusting member (13) is the stopper portion (2c). A liquid-filled bush characterized in that the orifice characteristic of the second orifice (15) is made variable so that it can move forward and backward.