JP2000170825A - Vibration control device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To vibrate a movable wall in a high frequency zone without using a large-sized actuator and also enlarge an amplitude sufficiently and restrain the aging drop of a vibration proof performance. SOLUTION: A drive wall 56 receiving the pressure from a liquid in a fluid enclose chamber 62 has about three times of pressure receive area for that of a membrane 54. By reciprocating the drive wall 56 to the volume expansion/ shrinkage direction of the fluid enclose chamber 62 by the action of the magnetic force to an attraction plate 68 by a solenoid actuator 70, a periodical pressure change is generated in the liquid enclosed in the fluid enclose chamber 62 and the pressure change is transmitted to the membrane 54 through the liquid. Meantime, the amplitude of the drive wall 56 is enlarged and transmitted to the membrane 54 in response to the ratio between the pressure receive area of the drive wall 56 and the pressure receive area of the membrane 54.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an anti-vibration device which is applied to, for example, automobiles and general industrial machines and absorbs vibration from a vibration generating portion. The present invention relates to a controllable liquid-filled vibration damping device.

[0002]

2. Description of the Related Art A vibration isolator is provided, for example, as an engine mount between an engine of a vehicle serving as a vibration generating unit and a vehicle body serving as a vibration receiving unit. Transmission to the vehicle body side. This type of vibration isolator has a liquid-filled type in which a pressure-receiving liquid chamber having an elastic body serving as a vibration-isolating body as a part of an inner wall and a sub-liquid chamber communicating with the pressure-receiving liquid chamber through an orifice are provided. There is something. According to this liquid filled type vibration damping device, the liquid flows between the pressure receiving liquid chamber and the sub liquid chamber through the orifice together with the deformation of the elastic body at the time of vibration input, so that the internal friction of the elastic body and the liquid column resonance are reduced. Vibration energy can be effectively absorbed by a change in the pressure of the liquid.

[0003] Further, there is a liquid filled type vibration damping device in which the vibration damping effect is enhanced by controlling the internal pressure of a pressure receiving liquid chamber at the time of vibration input. As a structure of such a vibration isolator,
For example, a movable wall constituting a part of a partition wall of the pressure receiving liquid chamber is elastically supported by an elastic film or the like, and the movable wall is reciprocated in response to input vibration by an actuator using a voice coil, an electromagnet, a piezoelectric element, or the like. (Vibration) forcibly expands / contracts the internal volume of the pressure receiving liquid chamber to control the internal pressure of the pressure receiving liquid chamber. The actuator used in such a hydraulic pressure control type vibration isolator is directly connected to the movable wall by a connecting member such as a rod, and transmits driving force to the movable wall through this connecting member to reciprocate the movable wall. Some have a moving structure.

[0004]

However, in the hydraulic control type vibration damping device having the above-described actuator, the vibration frequency and amplitude of the movable wall are limited by the capability of the actuator. Therefore, in order to vibrate the movable wall in a high frequency range and sufficiently increase the amplitude of the movable wall, a large-sized actuator capable of outputting a large power and capable of reciprocating the connecting member with a sufficiently long stroke is required.

In an actuator that reciprocates a movable wall via a connecting member, the connecting member slides via a sliding bearing when the connecting member reciprocates. For this reason, if the sliding bearings of the actuator are worn, the output may be reduced or a failure may occur, and the anti-vibration performance of the anti-vibration device may decrease over time.

An object of the present invention is to provide a vibration isolator that can vibrate a movable wall in a high frequency range and sufficiently increase the amplitude without using a large-sized actuator and that has a small deterioration in performance over time. Is to provide.

[0007]

According to a first aspect of the present invention, there is provided a vibration isolator connected to one of a vibration generator and a vibration receiver, and a first mounting member connected to the other of the vibration generator and the vibration receiver. A second attachment member, and an elastic body that is disposed between the first attachment member and the second attachment member and that can be elastically deformed;
Liquid is sealed, a pressure-receiving liquid chamber whose internal volume expands and contracts due to deformation of the elastic body with the elastic body as a part of the inner wall, and a fluid sealing chamber in which fluid is sealed and arranged adjacent to the pressure-receiving liquid chamber, Partitioning between the pressure-receiving liquid chamber and the fluid-filled chamber, a movable wall capable of being displaced in the volume expansion / contraction direction with respect to the pressure-receiving liquid chamber and the fluid-filled chamber, and a part of a partition wall of the fluid-filled chamber, A drive wall having a larger pressure receiving area than the movable wall and capable of being displaced in the volume expansion / contraction direction with respect to the fluid sealing chamber; and a drive member formed of a magnetic material and displaced in the volume expansion / contraction direction integrally with the drive wall. A driving member; and an electromagnetic actuator for applying a magnetic force to the driven member to reciprocate the driving wall in a volume expansion / contraction direction with respect to the fluid sealing chamber.

[0008] According to the vibration damping device having the above-described structure, the drive wall forming a part of the inner wall of the fluid-filled chamber has a wider pressure-receiving area than the movable wall separating the pressure-receiving liquid chamber and the fluid-filled chamber, and The electromagnetic actuator applies a magnetic force to the driven member to reciprocate the drive wall in the volume enlarging / reducing direction of the fluid enclosing chamber. A periodic pressure change occurs, and this pressure change is transmitted to the movable wall partitioning between the pressure receiving liquid chamber and the fluid sealing chamber via the fluid, so that the movable wall reciprocates in the volume expansion and contraction direction and receives the pressure receiving liquid. Periodic pressure changes are transmitted to the liquid enclosed in the chamber. At this time, if the fluid sealed in the fluid sealing chamber is a non-compressible fluid or a fluid that can be regarded as approximately an incompressible fluid, it depends on the ratio between the pressure receiving area of the movable wall and the pressure receiving area of the drive wall. As a result, the amplitude of the driving wall is enlarged and transmitted to the movable wall.

As a result, even if the amplitude when the driving wall is reciprocated by the electromagnetic actuator is small, if the pressure receiving area of the driving wall is made sufficiently large with respect to the pressure receiving area of the movable wall, a large actuator is not used. Since the amplitude when the movable wall is reciprocated can be made sufficiently large, it is possible to cause a sufficiently large pressure change in the liquid in the pressure receiving liquid chamber.

Therefore, when the vibration is transmitted from the vibration generating section to the first mounting member or the second mounting member, the elastic body is deformed by the vibration, and the vibration is absorbed by the internal friction of the elastic body. The transmission of vibration to is suppressed. Further, the elastic body is deformed by the vibration and the liquid pressure in the pressure receiving liquid chamber is about to change, but the movable wall reciprocates with a sufficiently large amplitude. The reciprocation of the pressure can sufficiently suppress the change in the liquid pressure in the pressure receiving liquid chamber, and can effectively suppress the transmission of vibration to the vibration receiving portion.

In the vibration isolator of the present embodiment, an electromagnetic actuator having no sliding parts such as a rod is used as an actuator for reciprocating the movable wall.
It is difficult for the performance of the actuator to be reduced or the vibration isolation performance to be reduced due to a failure or the like, and the reliability of the device can be improved.

According to a second aspect of the present invention, there is provided the vibration isolator according to the first aspect, further comprising control means for controlling the driving of the electromagnetic actuator in response to a vibration input from a vibration generator.

According to the vibration damping device having the above structure, the control means controls on / off of the electromagnetic actuator in accordance with the vibration frequency by controlling the driving of the electromagnetic actuator in accordance with the vibration input. Or, if the frequency or the like when the driving wall is reciprocated by the electromagnetic actuator is controlled, vibrations over a wide frequency range can be effectively absorbed.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A vibration isolator according to an embodiment of the present invention will be described with reference to the drawings.

(Structure of Embodiment) FIGS. 1 to 3 show a vibration isolator according to an embodiment of the present invention. The symbol S in the figure indicates the axis of the apparatus, and the following description will be made with the direction along this axis as the axial direction. The vibration isolator 10 is shown in FIG.
As shown in FIG. 1, the outer frame portion is formed of a bottomed cylindrical outer tube fitting 12 having a bottom portion at the bottom. The outer tube fitting 12 is formed in a two-stage cylindrical shape having different diameters on the upper side and the lower side.
The diameter is larger than 6. A stepped flange portion 18 is formed between the upper cylindrical portion 14 and the lower cylindrical portion 16. At the bottom of the lower cylindrical portion 16, a bolt 20 fastened and fixed to a vehicle body (not shown) which is a vibration receiving portion is implanted. In the upper cylindrical portion 14, a lower cylindrical portion 16
The support cylinder 22 having an outer diameter longer than the inner diameter of the support cylinder 22 is inserted. The support cylinder 22 has a small-diameter portion 22 at an intermediate portion in the axial direction.
A is formed, and the small-diameter portion 22A is
A groove 24 is formed in the outer peripheral surface along the circumferential direction.

A rubber elastic body 26 formed in a substantially truncated cone shape whose cross section is reduced upward is vulcanized and bonded to the upper inner peripheral surface of the support cylinder 22. A top plate fitting 28 is fixed to the surface by vulcanization bonding.
A bolt 30 that is fastened and fixed to the engine side, which is a vibration generating unit, protrudes from the center portion of the top plate 28 along the axis S. At the center of the bottom surface of the elastic body 26, an elastic inner wall portion 32 is formed which is recessed in a circular concave shape toward the top surface side.

A substantially cylindrical partition member 34 is inserted into the support cylinder 22 so as to contact the bottom of the elastic body 26. On the upper surface of the partition member 34, a first liquid chamber forming portion 36 having a circular concave shape is formed. The first liquid chamber forming part 36 includes:
The inner diameters of the upper side and the lower side are different from each other. The upper side is a large diameter portion 36A, and the lower side is a small diameter portion 36B.

On the other hand, on the lower surface of the partition member 34, a circular concave second liquid chamber forming portion 38 is formed coaxially with the first liquid chamber forming portion 36. Here, the second liquid chamber forming portion 38 is
The inner diameter of the liquid chamber forming portion 36 is longer than that of the small diameter portion 36B, and is smaller in the axial direction than the first liquid chamber forming portion 36.
Further, the partition member 34 penetrates from the bottom surface of the first liquid chamber forming portion 36 to the bottom surface of the second liquid chamber forming portion 38, and the liquid chamber forming portion 36,
A communication portion 40 that communicates between 38 is formed along the axis S. The first liquid chamber forming portion 36 communicates with the elastic inner wall 32 of the elastic body 26, and forms a pressure receiving liquid chamber 37 which is a large liquid chamber together with the elastic inner wall 32.

On the outer peripheral surface of the partition member 34, a groove 42 having a rectangular cross section is formed at an intermediate portion in the axial direction. This groove 42
Are formed over the entire circumference along the circumferential direction, and the grooves 42
The large diameter portion 36A of the first liquid chamber forming portion 36
A communication hole 42A that communicates with the communication hole is formed. Partition member 3
4 is in close contact with the inner peripheral surface of the small-diameter portion 22A of the support cylinder 22, and the outer peripheral side of the groove 42 is closed by the inner peripheral surface of the small-diameter portion 22A of the support cylinder 22. In addition, the small diameter portion 22
A has a communication hole 22B penetrating in the circumferential direction with respect to the axis S.
Are formed. The annular space formed in the groove 42 accommodates the pressure receiving liquid chamber 37 in the groove 24 of the support cylinder 22.
An orifice 46 for absorbing shake vibration, which is a liquid passage communicating with a sub liquid chamber 44 formed therein, is formed.

Between the outer cylinder fitting 12 and the support cylinder 22,
An intermediate cylinder 48 having a thin cylindrical shape is arranged so as to cover the entire outer periphery of the support cylinder 22. The lower end of each of the support cylinder 22 and the intermediate cylinder 48 has the outer cylinder fitting 1.
In this state, the upper end of the upper cylindrical portion 14 is swaged toward the axial center S, whereby the support cylinder 22 and the intermediate cylinder 48 enter the outer cylinder fitting 12. Fixed.

On the inner peripheral surface of the intermediate cylinder 48, both ends in the axial direction of a rubber diaphragm 50 formed in a thin cylindrical shape are respectively vulcanized and bonded. The diaphragm 50 closes the outer peripheral side of the groove portion 24 of the support cylinder 22, and is curved in an arch shape so that an axial middle portion protrudes into the groove portion 24. Here, the thick cylindrical space formed in the groove portion 24 whose outer peripheral side is closed by the diaphragm 50 is a sub liquid chamber 44 which is a small liquid chamber. Further, since the axial middle portion of the diaphragm 50 is curved in an arch shape, elastic deformation in the radial direction of the diaphragm 50 is enabled between the outer peripheral surface of the diaphragm 50 and the inner peripheral surface of the intermediate cylinder 44. An air chamber 52 is formed. And the pressure receiving liquid chamber 3
7. A liquid such as water or oil is sealed in the sub-liquid chamber 44 and the orifice 46 communicating these liquid chambers 37 and 44.

On the inner peripheral surface of the small diameter portion 36B of the partition member 34, the outer peripheral surface of a membrane 54, which is a thick disk-shaped elastic film, is vulcanized and bonded to the axially intermediate portion. Thus, the small diameter portion 36B is partitioned into an upper space forming a part of the pressure receiving liquid chamber 37 and a lower space adjacent to the pressure receiving liquid chamber 37 via the membrane 54. Partition member 3
The lower end of the second liquid chamber forming portion 38 in FIG. 4 is closed by a thick disk-shaped drive wall 56. The driving wall 56 includes a resin driving disk 58 formed in a disk shape and an elastic film 60 formed in a ring shape. This elastic film 60
The outer peripheral surface of the driving disk 58 and the inner peripheral surface of the second second liquid chamber forming portion 38 are respectively vulcanized and bonded, so that the elastic plate 58 and the second second liquid chamber forming portion 38 Is sealed.

The space formed in the partition member 34 between the membrane 54 and the drive wall 56, that is, the lower side of the small diameter portion 36B partitioned by the membrane 54, the communication portion 40 and the drive wall 56 is closed. The space formed by the second liquid chamber forming part 38 is a fluid sealing chamber 62 in which a fluid is sealed. The same liquid as the liquid sealed in the pressure receiving liquid chamber 37 is sealed in the fluid sealing chamber 62. Here, the membrane 54 is configured to be elastically deformable in the axial direction which is the volume expansion / contraction direction with respect to the pressure receiving liquid chamber 37 and the fluid sealing chamber 62, and the driving wall 56 is configured such that the elastic film 60 is elastically deformed to form the fluid sealing chamber. The shaft 62 can be displaced in the axial direction which is the volume expansion / contraction direction.

The membrane 54 and the driving wall 56 receive pressure from the liquid sealed in the fluid sealing chamber 62, respectively, and the driving wall 56 receives the pressure from the liquid in the fluid sealing chamber 62 that is larger than the pressure receiving area of the membrane 54. It has a pressure receiving area. Specifically, the driving wall 56 is formed such that its pressure receiving area is about three times as large as the pressure receiving area of the membrane 54. Accordingly, when the drive wall 56 is displaced in the volume expansion / contraction direction, the displacement of the drive wall 56 is enlarged according to the ratio between the pressure receiving area of the drive wall 56 and the pressure receiving area of the membrane 54, and the drive wall 56 is displaced in volume. The membrane 54 is largely displaced in the volume expansion / contraction direction only by making a small displacement in the expansion / contraction direction.

On the outer peripheral surface of the partition member 34, a flange portion 34A extending radially outward is formed at a lower end portion.
A ring-shaped spacer 6 is provided on the lower surface of the flange portion 34A.
4 is in contact. Flange 34A and spacer 64
Is held between the lower surface on the outer peripheral side of the small diameter portion 22A of the support cylinder 22 and the upper surface on the inner peripheral side of the flange portion 18 of the outer cylinder fitting 12. Thereby, the partition member 34 is fixed at a predetermined position in the axial direction.

An outer peripheral portion of a thin disk-shaped leaf spring 66 is sandwiched between the flange portion 34A and the spacer 64. The leaf spring 66 is formed in a tapered shape such that a central portion protrudes upward with respect to an outer peripheral portion in a non-deformed state, and the central portion of the leaf spring 66 is pressed against the outer peripheral portion of the driving disk 58. Thus, the drive wall 56 is constantly urged in the volume reduction direction (upward) with respect to the pressure receiving liquid chamber 37. Drive disk 5
8 has a circular convex boss 58A projecting downward.
Are formed. Then, the hollow portion 66 of the spacer 64
Inside, a suction plate 68 fixed to the lower surface of the boss portion 58A passing through the center hole of the leaf spring 66 and connected to the drive disk 58
Is arranged. The suction plate 68 is made of a magnetic material such as iron, and has a tapered portion which is inclined downward toward the outer end at an outer peripheral portion on the upper surface side. This prevents the suction plate 68 from interfering with the leaf spring 66 when the inner peripheral side of the leaf spring 66 is flexed and deformed with respect to the outer peripheral side.

An electromagnetic actuator 70 is inserted into the lower cylindrical portion 16 of the outer tube fitting 12. The electromagnetic actuator 70 includes a core 72 made of iron, a permanent magnet 74, and a coil 76. The core 72 is formed in a substantially cylindrical shape, and the outer peripheral portion of the upper surface is in contact with the lower surface of the spacer 64. The permanent magnet 74 is formed in a disk shape, and
2 is buried so as to be flush with the center of the upper surface. As a result, the magnetic force from the permanent magnet 74 always acts on the suction plate 68, and when the electromagnetic actuator 70 is stopped as shown in FIG. It is stationary at a neutral position where the upward biasing force of the spring 66 is balanced.

When the suction plate 68 is stationary at the neutral position, the elastic film 60 of the membrane rubber 54 and the driving wall 56 is
Is in a non-deformed state where almost no elastic deformation occurs in the axial direction. An annular groove is formed in the core 72 along the outer peripheral end of the permanent magnet 74.
A coil 76 is provided in the second annular groove, and is sealed in the annular groove by a resin lid member 78 formed in a ring shape.

A controller 80, which is a control means for the electromagnetic actuator 70, is provided outside the outer tube fitting 12, and the controller 80 is connected to the coil 76. Accordingly, when the drive current from the controller 80 is supplied to the coil 76, the electromagnetic actuator 70 causes a magnetic force corresponding to the drive current to act on the suction plate 68. Here, the controller 80 is operated by the vehicle power supply, detects the rotation speed and the rotation angle of the engine based on a crank signal from the engine crank, and determines whether idle vibration or shake vibration is generated, and timing of vibration generation. I can do it.

(Operation of Embodiment) Next, the operation of the vibration isolator 10 according to this embodiment will be described.

When the engine mounted on the top plate 28 operates, the vibration of the engine is transmitted to the elastic body 26 via the top plate 28. The elastic body 26 acts as a vibration absorber, and the vibration is absorbed by a vibration damping function based on internal friction of the elastic body 26.

In the vibration isolator 10 of the present embodiment, when a drive current is supplied to the coil 76, the electromagnetic actuator 7
With 0, a suction force acts on the suction plate 68. This allows
The suction plate 68 moves downward from the neutral position against the urging force of the leaf spring 66 as shown in FIG. 2, and the driving wall 56 connected to the suction plate 68 also deforms the elastic film 60 while bending the suction plate. It moves downward together with 68.

Electromagnetic actuator 7 for suction plate 68
The magnetic force (attraction force) from zero and the urging force of the leaf spring 66 are balanced at the lower limit position immediately before the attraction plate 68 contacts the permanent magnet 74. Synchronized with the timing when the suction plate 68 reaches the lower limit position, the controller 80
When the supply of the driving current to the driving disk is stopped, the suction plate 68 and the driving wall 56 move upward by the restoring force of the elastic film 60 and the urging force of the leaf spring 66 as shown in FIG.
8 stops at the upper limit position in contact with the bottom surface of the second liquid chamber forming portion 38.

Further, when the drive current is supplied again to the electromagnetic actuator 70 in synchronization with the timing when the suction plate 68 and the drive wall 56 reach the upper limit position, the suction plate 68 and the drive wall 56 move from the upper limit position to the lower limit position. . Therefore, by periodically repeating the supply / stop of the drive current to the electromagnetic actuator 70, the drive wall 56 can reciprocate at a desired frequency.

In the vibration isolator 10 of the present embodiment, the driving wall 56 has a pressure receiving area approximately three times as large as the pressure receiving area of the membrane 54, and the electromagnetic actuator 70 applies a magnetic force to the suction plate 68 as described above. By reciprocating the drive wall 56 in the volume expansion / contraction direction of the fluid sealing chamber 62, the drive wall 56 reciprocates in the volume expansion / contraction direction, and a periodic pressure change occurs in the liquid sealed in the fluid sealing chamber 62. This pressure change is transmitted via the liquid to the membrane 54 that partitions the pressure receiving liquid chamber 37 and the fluid sealing chamber 62. As a result, the membrane 54 reciprocates in the volume expansion / contraction direction, and the pressure receiving liquid chamber 37
A periodic pressure change is transmitted to the liquid enclosed in the liquid. At this time, the amplitude of the driving wall 56 in the volume expansion / contraction direction is increased according to the ratio of the pressure receiving area of the driving wall 56 to the pressure receiving area of the membrane 54 and transmitted to the membrane 54.

Next, control of the electromagnetic actuator 70 by the controller 80 when vibration is input from the engine will be described.

When the engine is running, the controller 80 determines, at regular intervals, whether idle vibration or shake vibration has occurred based on the crank signal.
When the controller 80 determines that the shake vibration, which is a vibration in a relatively low frequency range, is occurring from the engine, the controller 80 does not supply a current to the electromagnetic actuator 70. As a result, when shake vibration occurs,
The liquid in the pressure receiving liquid chamber 37 and the liquid in the sub liquid chamber 44 whose internal volumes change with the deformation of the elastic body 26 and the diaphragm 50 flow mutually through the orifice 46, and the viscous resistance of the liquid flow generated in the orifice space Vibration energy is absorbed by damping action based on liquid column resonance and the like, and shake vibration can be effectively absorbed.

On the other hand, if the controller 80 determines that idle vibration is occurring when idle vibration, which is a vibration in a relatively high frequency range, is generated from the engine, the electromagnetic actuator 70 responds to the vibration transmitted from the engine.
Drive. As a result, when idle vibration occurs,
Orifice 46 for absorbing shake vibration with large passage resistance
Is clogged, and the liquid pressure in the pressure receiving liquid chamber 37 tends to change with the deformation of the elastic body 26. However, the liquid in the pressure receiving liquid chamber 37 is reciprocated by the electromagnetic actuator 70. Changes in pressure can be suppressed, and idle vibration can be effectively absorbed.

Specifically, when the controller 80 determines that idle vibration has occurred, the controller 80 controls the electromagnetic actuator 70 as follows.

When idle vibration from the engine is input to the vibration isolator 10 and the top plate 28 descends in the direction of arrow D in FIG. 2, the controller 80, which has detected the lowering of the top plate 28 by the crank signal, uses the electromagnetic actuator. 7
0 to supply the driving current to the driving wall 56 and the membrane 54.
Is lowered. As a result, when the top plate fitting 28 descends, the internal volume of the pressure receiving liquid chamber 37 decreases and the hydraulic pressure tends to increase with the deformation of the elastic body 26, but the membrane 54 descends and the internal volume of the pressure receiving liquid chamber 37 decreases. , The pressure change in the pressure receiving liquid chamber 37 is suppressed. When the top plate 28 rises in the direction of the arrow U in FIG. 3, the controller 80 that has detected the rise of the top plate 28 by the crank signal,
The supply of the drive current to the electromagnetic actuator 70 is stopped, and the drive wall 56 and the membrane 54 are raised. As a result, when the top plate fitting 28 rises, the inner volume of the pressure receiving liquid chamber 37 expands as the elastic body 26 deforms and the hydraulic pressure tends to decrease, but the membrane 54 rises and the internal volume of the pressure receiving liquid chamber 37 increases. Is reduced, the pressure change in the pressure receiving liquid chamber 37 is suppressed at this time as well. As a result, since the energy of the idle vibration from the engine can be efficiently absorbed by the liquid in the pressure receiving liquid chamber 37, the transmission of the idle vibration to the vehicle body side can be effectively suppressed.

According to the vibration isolator 10 of the present embodiment described above, the amplitude of the drive wall 56 is enlarged and transmitted to the membrane 54 in accordance with the ratio between the pressure receiving area of the drive wall 56 and the pressure receiving area of the membrane 54. Therefore, the electromagnetic actuator 70
Therefore, even if the amplitude at the time of reciprocating the driving wall 56 is small, if the pressure receiving area of the driving wall 56 is set to about three times the pressure receiving area of the membrane 54, the membrane 54 can be moved without using a large actuator having a large stroke. Since the amplitude at the time of reciprocation can be made sufficiently large, it is possible to cause a sufficiently large pressure change in the liquid in the pressure receiving liquid chamber 37. As a result, when the vibration is input from the engine,
Fluctuations in the hydraulic pressure in the motor 7 can be sufficiently suppressed, and the transmission of vibration to the vehicle body can be effectively suppressed.

Further, in the vibration isolator 10 of this embodiment, the electromagnetic actuator 70 having no sliding parts such as a rod is used as an actuator for reciprocating the driving wall 54 and the membrane 54, so that the performance of the actuator deteriorates. It is unlikely that the anti-vibration ability is reduced due to a failure or the like, and the reliability of the device can be improved.

In the above description, the controller 80
When it is determined that a shake vibration is occurring, no current is supplied to the electromagnetic actuator 70. However, at the same time as the shake vibration, vibration having a small amplitude at a relatively high frequency that may be input is effectively absorbed. Also, when the shake vibration is generated, the controller 80 drives the electromagnetic actuator 70 in response to the minute amplitude vibration that is input simultaneously with the shake vibration in the same manner as when the idle vibration is generated, and the controller 80 causes the membrane 54 to reciprocate. May be controlled.

Further, in the vibration isolator 10 of this embodiment, the pressure receiving area of the driving wall 56 is set to be about three times the pressure receiving area of the membrane 54.
The ratio with respect to the pressure receiving area is not limited to about three times in the present embodiment. If the suction force of the electromagnetic actuator 70 on the suction plate 68 has a margin, the driving wall can be further increased with respect to the pressure receiving area of the membrane 54. It is also possible to increase the pressure receiving area of 56.

In the vibration isolator 10 of this embodiment, only the case where the electromagnetic actuator 70 is driven to move the membrane 54 in the volume expansion / contraction direction with respect to the pressure receiving liquid chamber 37 at the time of inputting the idle vibration has been described. 4
Considering that 6 is for shaking vibration absorption, even when vibrations in a frequency range different from the idle vibration are input, it corresponds to vibrations in a frequency range different from the idle vibration, for example, muffled sound. Then, the vibration can be absorbed by driving the electromagnetic actuator 70.

In the vibration isolator 10 of the present embodiment, the same type of liquid as the liquid sealed in the pressure receiving liquid chamber 37 is sealed in the fluid sealing chamber 62. A fluid different from the liquid sealed in the chamber 37 may be sealed, and the fluid includes a gas such as air.
However, when gas is sealed in the fluid sealing chamber 62, gas is more compressible than liquid,
When the rigidity of the diaphragm 4 is high, the expansion ratio of the amplitude of the membrane 54 to the amplitude of the driving wall 56 becomes small.

The electromagnetic actuator 70 of the present embodiment
A permanent magnet 74 for applying a magnetic force to the attraction plate 68 is disposed at the center of the upper surface of the core 72. However, a coil is disposed in place of the permanent magnet 74, and a coil 76 is formed by the coil and the core 72. A second electromagnet may be formed on the inner peripheral side of the magnet and a magnetic force may always be applied to the suction plate 68 by the second electromagnet when the electromagnetic actuator 70 is operated. Alternatively, the suction plate 68 may be formed of a permanent magnet, and an alternating magnetic field may be applied by the electromagnetic actuator 70 to reciprocate the suction plate 68 in the axial direction.

[0048]

As described above, according to the vibration damping device of the present invention, the movable wall can be vibrated in a high frequency range without using a large-sized actuator and the amplitude can be sufficiently increased.
In addition, it is possible to suppress the deterioration of the vibration isolation performance over time.

[Brief description of the drawings]

FIG. 1 is a side cross-sectional view showing a state in which a drive wall is in a neutral position in a vibration isolator according to an embodiment of the present invention.

FIG. 2 is a side cross-sectional view showing a state in which a drive wall is at a lower limit position in the vibration isolator according to the embodiment of the present invention.

FIG. 3 is a side cross-sectional view showing a state in which a drive wall is at an upper limit position in the vibration isolator according to the embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Vibration isolator 12 Outer cylinder fitting (1st mounting member) 26 Elastic body 28 Top plate fitting (2nd mounting member) 37 Pressure receiving liquid chamber 54 Membrane (movable wall) 56 Driving wall 62 Fluid sealing chamber 68 Suction plate (Coated) Drive member) 70 electromagnetic actuator 80 controller (control means)

Claims (2)

[Claims] A first mounting member connected to one of the vibration generating unit and the vibration receiving unit; a second mounting member connected to the other of the vibration generating unit and the vibration receiving unit; and the first mounting An elastic body disposed between the member and the second mounting member and capable of elastic deformation; a pressure-receiving liquid chamber in which a liquid is sealed and the internal volume of which expands and contracts by deformation of the elastic body with the elastic body being a part of an inner wall; And a fluid sealed chamber in which a fluid is sealed and arranged adjacent to the pressure receiving liquid chamber; and a partition between the pressure receiving liquid chamber and the fluid sealing chamber;
A movable wall capable of being displaced in a volume expansion / contraction direction with respect to the pressure-receiving liquid chamber and the fluid-filled chamber; and a part of a partition wall of the fluid-filled chamber, having a larger pressure-receiving area than the movable wall, and A drive wall that is displaceable in the expansion and contraction direction; a driven member that is formed of a magnetic material and that is displaced in the volume expansion and contraction direction integrally with the drive wall; An electromagnetic actuator for reciprocating a wall in a volume expansion / contraction direction with respect to the fluid sealing chamber. 2. The vibration isolator according to claim 1, further comprising control means for controlling driving of said electromagnetic actuator in response to a vibration input from a vibration generator.