JP3714368B2 - Liquid-filled bush - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a liquid-filled bush used as an anti-vibration device or an anti-vibration support device in an automobile or the like. The liquid-filled bush of the present invention is frequently used particularly as an engine mount for automobiles.
[0002]
[Prior art]
Conventionally, 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, and a plurality of liquid chambers partitioned by the elastic body are communicated with each other via an orifice, A liquid-enclosed bush in which a working fluid is encapsulated in a liquid chamber is known. However, in a conventional liquid-enclosed bush, only a single orifice that connects a plurality of liquid chambers to each other is provided. Therefore, when this orifice is set so as to attenuate the low frequency vibration, the high frequency vibration cannot be absorbed and suppressed. On the other hand, both the low frequency vibration and the high frequency vibration can be absorbed and suppressed. A possible product is needed. In addition, as disclosed in Japanese Patent Publication No. 5-55739, a liquid-filled bush provided with a high-frequency device has been developed to absorb high-frequency vibration. According to this liquid-filled bush, Since the resonance frequency is constant for each product and is not changed, there is a problem that high-frequency vibration having a frequency different from the setting cannot be absorbed and suppressed.
[0003]
[Problems to be solved by the invention]
In view of the above points, the present invention is provided with a second orifice that absorbs high-frequency vibration in addition to an orifice that attenuates low-frequency vibration, and the orifice characteristic of the second orifice is variable, so that it can be used in a wide frequency range. An object of the present invention is to provide a liquid-filled bush that can absorb and suppress high-frequency vibrations.
[0004]
[Means for Solving the Problems]
In order to achieve the above object, the liquid-filled bush of the present invention has a plurality of parts that are partitioned by the elastic body by connecting the outer mounting part to the outer peripheral side of the inner mounting part via an elastic body made of rubber-like elastic material. In the liquid-filled bush in which the liquid chambers communicate with each other through an orifice and the working fluid is sealed in the liquid chamber, a stopper that is disposed in the one liquid chamber at the inner mounting portion and protrudes in the vibration input direction A gap adjusting member facing the stopper portion and the vibration input direction is provided on the outer mounting portion, and a gap between the stopper portion and the gap adjusting member is a second orifice, and the gap adjusting member is The orifice characteristic of the second orifice is made variable by changing the size of the gap so that it can advance and retreat toward the stopper portion.
[0005]
[Action]
When low-frequency vibration is input to the liquid-filled bushing of the present invention having the above configuration, the “orifice” attenuates this, and when high-frequency vibration is input, the “second orifice” absorbs this. In addition, since the gap adjusting member can be moved back and forth toward the stopper portion and the orifice characteristic of the second orifice is variable, the high frequency vibration of different frequencies is absorbed and suppressed within this variable range. It is possible.
[0006]
DETAILED DESCRIPTION OF THE INVENTION
In order to match the orifice characteristic of the second orifice to the frequency of the input vibration, a sensor, a controller and a drive mechanism are used in combination with the liquid-filled bush of the present invention. That is, a sensor that measures the input vibration, a controller that determines the optimum gap size according to a signal input from the sensor, and determines the displacement amount of the gap adjusting member in accordance with this, and a gap according to the instructions of the controller. And a drive mechanism such as an air cylinder that actually reciprocates the adjustment member.
[0007]
【Example】
Next, embodiments of the present invention will be described with reference to the drawings.
[0008]
As shown in FIGS. 1 and 2, the outer side (outer peripheral side) provided with the case 4, the outer cylinder 5 and the bracket 6 on the outer peripheral side of the inner (inner peripheral side) mounting portion 1 provided with the inner cylinder 2. The portion 3 is disposed, 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 outer cylinder 5 integrated with the bracket 6 is provided on the outer peripheral side of the case 4. It is inserted.
[0009]
The inner cylinder 2 has a mounting hole 2a and is basically formed in a cylindrical shape, but has a convex shape at the axially central portion of the outer peripheral surface thereof in the vertical direction in the figure, which is the main vibration input direction. A pair of stopper portions 2b and 2c are integrally projected. The elastic body 7 plays a role of defining the first liquid chamber 8 and the second liquid chamber 9 inside the bush in addition to connecting the inner cylinder 2 and the case 4. A pair of leg portions (also referred to as rubber leg portions) 7a, a diaphragm portion 7b, and a pair of axial wall portions (also referred to as rubber wall portions) 7c are integrally provided. The covered portion 7d and the buffer portions 7e and 7f covered at the tip portions of the stopper portions 2b and 2c are integrally provided and integrally vulcanized. The case 4 includes annular portions 4a and 4b at both ends in the axial direction, and the pair of axial portions 4a and 4b in the axial direction is a pair of substantially arc-shaped components indicated by reference numeral 4c in FIG. The annular portions 2a (one on the left side in FIG. 2) that are integrally connected to each other are formed in a substantially U-shaped cross section, and an orifice 10 is provided inside the U-shape. And the second liquid chamber 9 are communicated with each other, and a hydraulic fluid (also referred to as an inner sealing liquid) 11 such as a viscous fluid is sealed in both the chambers 8 and 9. Reference numeral 10 a is an opening on the first liquid chamber 8 side of the orifice 10, and 10 b is an opening on the second liquid chamber 9 side. Reference numeral 12 denotes a straight portion.
[0010]
The bracket 6 is provided with a housing recess 6a facing the second liquid chamber 9, and a piston-like gap adjusting member facing the stopper portion 2c disposed in the second liquid chamber 9 in the housing recess 6a. (Also referred to as a gap adjusting member) 13 is accommodated, and a gap (also referred to as a gap) 14 between the stopper portion 2c whose tip is covered with the buffer portion 7f and the gap adjusting member 13 is defined as a second orifice 15, and the gap The adjusting member 13 can be moved back and forth toward the stopper portion 2c, and the orifice characteristic of the second orifice 15 is variable. The advancement / retraction of the gap adjusting member 13 is performed by the operation of a driving mechanism (also referred to as a driving device) 16 such as an air cylinder accommodated in the bracket 6, that is, when the operating rod 16 a of the driving mechanism 16 protrudes. When the member 13 is raised and the size G of the gap 14 is narrowed, and when the operation rod 16a of the drive mechanism 16 is retracted, the gap adjusting member 13 is lowered and the size G of the gap 14 is expanded. Reference numeral 17 is a sensor for measuring input vibration, and reference numeral 18 is a controller for determining an optimum size G of the gap 14 based on a signal input from the sensor 17 and determining a displacement amount of the gap adjusting member 13 in accordance with this. The drive mechanism 16 reciprocates the gap adjusting member 13 in accordance with an instruction from the controller 18.
[0011]
The liquid-filled bush having the above-described configuration is attached to the vehicle body side of the automobile with one of the inner attachment portion 1 and the outer attachment portion 3, for example, and attached to the engine side with the other to support the vibration isolation of the engine. Therefore, when vibration of low frequency and large amplitude is input to the bush, the elasticity of the leg portion 7a of the elastic body 7 and the flow resistance or liquid column resonance of the working fluid 11 flowing through the orifice 10 are obtained. This vibration is effectively damped. In addition, when high-frequency small-amplitude vibration having a predetermined specific frequency is input to the bush, the hydraulic fluid 11 enters and exits the second orifice 15 and resonates as shown by arrows in FIG. The absolute spring constant of the bush can be kept low, thereby effectively absorbing and suppressing this high frequency, small amplitude vibration. When the hydraulic fluid 11 enters and exits the second orifice 15, the wall portion 7c of the elastic body 7 repeats expansion and contraction accordingly.
[0012]
Further, when vibrations with high frequency and small amplitude of different frequencies occur due to changes in the vehicle speed or the engine speed, the sensor 17 measures the frequency and amplitude, and the controller 18 calculates the result. Accordingly, 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 changes the orifice characteristic or resonance frequency of the second orifice 15 to this vibration. Change to suit. Therefore, in this state, since the bush receives the new high frequency small amplitude vibration, the new high frequency small amplitude vibration can be effectively absorbed and suppressed. Therefore, it is possible to provide a liquid-filled bush that can effectively absorb and suppress high-frequency and small-amplitude vibrations over a wide frequency range, and exhibits excellent damping characteristics or vibration-proof performance.
[0013]
【The invention's effect】
The present invention has the following effects.
[0014]
That is, in the liquid-filled bush of the present invention having the above-described configuration, the “orifice” attenuates this when low frequency vibration is input to the bush, and “second orifice” when high frequency vibration is input. ”Suppresses this absorption, and the gap adjusting member can be moved back and forth toward the stopper portion. By changing the size of the gap between the gap adjusting member and the stopper portion , the orifice characteristic of the second orifice is variable. Therefore, high frequency vibrations with different frequencies can be absorbed and suppressed within this variable range. Therefore, it is possible to provide a liquid-filled bush that can effectively absorb and suppress high-frequency vibrations over a wide frequency range, and exhibits excellent damping characteristics or vibration-proof performance.
[Brief description of the 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.
DESCRIPTION OF SYMBOLS 1 Inner attachment part 2 Inner cylinder 2a Attachment hole 2b, 2c Stopper part 3 Outer attachment part 4 Case 5 Outer cylinder 6 Bracket 6a Housing recessed part 7 Elastic body 7a Leg part 7b Diaphragm part 7c Wall part 7d Cover part 7e, 7f Buffer Portion 8 First liquid chamber 9 Second liquid chamber 10 Orifices 10a, 10b Opening 11 Hydraulic fluid 12 Straightening portion 13 Gap adjusting member 14 Gap 15 Second orifice 16 Drive mechanism 16a Actuating rod 17 Sensor 18 Controller

Claims (1)

An outer mounting portion (3) is connected to the outer peripheral side of the inner mounting portion (1) via an elastic body (7) made of a rubber-like elastic material, and a plurality of liquid chambers partitioned by the elastic body (7) ( 8) In a liquid-filled bush in which (9) communicates with each other through an orifice (10) and the working fluid (11) is sealed in the liquid chamber (8) (9), the inner mounting portion (1) A stopper portion (2c) disposed in one liquid chamber (9) and projecting in the vibration input direction is provided, and the outer mounting portion (3) is opposed to the stopper portion (2c) in the vibration input direction. A gap adjusting member (13) is provided, the gap (14) between the stopper portion (2c) and the gap adjusting member (13) is a second orifice (15), and the gap adjusting member (13) is the stopper. part size towards (2c) the gap as retractable (14) Fluid-filled bushing, characterized in that the orifice characteristics of the second orifice (15) is made variable by changing the G).

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