JP4202866B2 - Vibration isolator - Google Patents

Description

  The present invention relates to a vibration isolator that is applied to, for example, automobiles and general industrial machines and absorbs and attenuates vibrations transmitted from a vibration generating unit such as an engine to a vibration receiving unit such as a frame.

  In an automobile, an engine mount as an anti-vibration device is disposed between the engine and the vehicle body (frame). Such an engine mount absorbs vibration energy by the internal resistance of the rubber elastic body, and attenuates vibration from the engine to suppress vibration transmitted to the frame. However, the engine that is the vibration generating unit is used under various operating conditions from the state of idling operation to the maximum rotational speed, and the frequency of the generated vibration from the engine also varies within a wide range. Therefore, the engine mount must be able to handle a wide range of frequencies. For this reason, as the engine mount, a pressure receiving liquid chamber and a sub liquid chamber having a rubber elastic body as a part of the partition are provided inside, and the space between them is connected by an orifice which is a restriction passage. Things have been proposed.

  FIG. 6 shows an example of a liquid-filled vibration isolator applied as an engine mount. The vibration isolator 70 is disposed between a connection fitting 72 connected to the engine via a bolt shaft 73, a holder 74 connected to the vehicle body via a bolt shaft 75, and the connection fitting 72 and the holder 74. An elastic body 80 serving as a main body for absorbing vibration transmitted from the engine is provided, and a partition member 76 fitted into the holder 74 is provided.

  The elastic body 80 is made of a rubber material, and is integrally coupled to the connection fitting 72 and the holder 74 by vulcanization adhesion. Further, in the vibration isolator 70, a pressure receiving liquid chamber 78 in which a part of the partition wall is formed by the elastic body 80, a first sub liquid chamber 82 in which a part of the partition wall is formed by the diaphragm 84, and the diaphragm 84 are provided. A first air chamber 86 adjacent to the first sub liquid chamber 82 is provided, and a shake orifice 88 that connects the pressure receiving liquid chamber 78 and the first sub liquid chamber 82 is formed in the partition member 76. ing. In addition, a second sub liquid chamber 92 and a second air chamber 94 which are adjacent to each other are provided in the partition member 76 via a rubber membrane 90, and the second sub liquid chamber 92 is connected to the pressure receiving liquid chamber 78. An idle orifice 96 is formed. The pressure receiving liquid chamber 78, the sub liquid chambers 82 and 92, and the orifices 88 and 96 are filled with a liquid such as water or ethylene glycol.

  In the vibration isolator 70, a vacuum switching valve (hereinafter referred to as “VSV”) 100 is connected to the second air chamber 94 via a pipe 98, and this VSV 100 is controlled by a controller (not shown). The air chamber 94 is selectively communicated with either a negative pressure supply source such as a surge tank or the atmospheric space. The controller detects the frequency of the input vibration from the engine that is the vibration generating unit, and controls the VSV 100 according to the detected frequency of the input vibration.

  Specifically, the controller communicates the second air chamber 94 with the atmospheric space by the VSV 100 when idling vibration (20 Hz to 40 Hz) is input, and the second air chamber 94 by the VSV 100 when traveling without idling vibration. Connect to a negative pressure source. Accordingly, in the vibration isolator 70, the membrane 88 can be elastically deformed in the volume expansion / contraction direction of the second sub liquid chamber 92 when the idle vibration is input, and the pressure receiving liquid chamber 78 and the second sub liquid are passed through the idle orifice 96. A liquid column resonance is generated between the chamber 92 and the idle vibration is effectively absorbed by the action of the liquid column resonance and the like through the idle orifice 96, and a shake vibration that is a vibration of less than 20 Hz during traveling is generated. Sometimes, a liquid column resonance occurs between the pressure receiving liquid chamber 78 and the first sub liquid chamber 82 through the shake orifice 88, and the shake vibration is effectively absorbed by the action of the liquid column resonance and the like through the shake orifice 88. The

  However, when the vehicle travels, high-frequency vibrations such as a booming sound (50 Hz to 100 Hz) are generated in addition to the shake vibrations. However, the vibration isolator 70 as shown in FIG. Therefore, when high-frequency vibration is input, the shake orifice 88 having a large liquid passage resistance is clogged, and the liquid pressure in the pressure receiving liquid chamber 78 increases. As a result, the vibration isolator 70 has a problem that the dynamic spring constant increases, and high-frequency vibration during traveling cannot be effectively absorbed.

  In order to solve the above problems, it is conceivable to add a membrane that is arranged facing the pressure receiving liquid chamber and elastically deforms by high-frequency vibration to the vibration isolator as shown in FIG. When such a membrane is added, the structure of the apparatus becomes complicated and the manufacturing cost increases, and at the time of idling vibration input, liquid column resonance through the idling orifice is suppressed and the absorption effect on idling vibration is reduced. There is also a fear.

  An object of the present invention is to provide a vibration isolator capable of effectively absorbing input vibrations in a wide frequency range including high frequency vibrations while simplifying the structure of the device in consideration of the above facts.

The vibration isolator according to the present invention includes a first attachment member connected to one of the vibration generator and the vibration receiver, a second attachment member connected to the other of the vibration generator and the vibration receiver,
An elastic body that is disposed between the first mounting member and the second mounting member and elastically deforms by input vibration from a vibration generating unit, and the elastic body is used as a part of a partition wall to deform the elastic body. A pressure-receiving liquid chamber whose internal volume expands and contracts, a limit passage for absorbing idle vibration whose one end is connected to the pressure-receiving liquid chamber, and the other end of the limit passage are connected to each other through the limit passage when idle vibration is input. The sub liquid chamber in which the liquid goes back and forth so as to resonate with idle vibration between the pressure receiving liquid chamber and another part of the partition wall in the pressure receiving liquid chamber constitutes an expansion / contraction that expands / contracts the internal volume of the pressure receiving liquid chamber A membrane that is elastically deformable in a direction, an air chamber that is disposed adjacent to the pressure-receiving liquid chamber via the membrane, and a vacuum that communicates the air chamber with any of a negative pressure supply source and an atmospheric space A switching valve; Introducing a negative pressure from the negative pressure source to the air chamber by the vacuum switching valve when entering the idle vibration, and a control means for said air chamber by the vacuum switching valve to the non-input time of idling vibration to communicate with the atmosphere space, The elastic deformation along the expansion / contraction direction of the membrane is restricted, and the pressure receiving liquid chamber and a stopper having an orifice formed so as to face the membrane are provided, and when the negative pressure is introduced into the air chamber Forming an auxiliary liquid chamber partitioned from the pressure receiving liquid chamber between the stopper and the membrane, and allowing the liquid to flow between the pressure receiving liquid chamber and the auxiliary liquid chamber through the orifice; and The flow resistance of the liquid in the orifice hole is transmitted from the vacuum switching valve when negative pressure is introduced into the air chamber. Characterized by being configured for higher order vibrations.

  In the vibration isolator according to the present invention, when the idle vibration is input, the control means introduces the negative pressure from the negative pressure supply source into the air chamber by the vacuum switching valve, whereby the action of the negative pressure introduced into the air chamber. As a result, the membrane is sucked to the inner wall side of the air chamber, and even if the fluid pressure in the pressure receiving fluid chamber changes, the membrane is restrained from elastic deformation, so the pressure receiving fluid chamber accompanying the elastic deformation of the membrane The decrease in the expansion elasticity of is prevented.

  As a result, when the elastic body is elastically deformed by idle vibration (20 Hz to 40 Hz) input from the vibration generating unit, the idle vibration is absorbed by the internal resistance of the elastic body, and at the same time, the internal volume is increased with the elastic deformation of the elastic body. By allowing the liquid to flow between the pressure-receiving liquid chamber and the sub-liquid chamber changing (expanding / contracting) through the restriction passage, the viscous vibration of the liquid and the liquid column resonance effectively absorb idle vibration. Can be attenuated.

  In the vibration isolator according to the present invention, when the idle vibration is not input, the control means causes the air chamber to communicate with the atmospheric space by the vacuum switching valve, so that the air chamber is maintained at substantially atmospheric pressure, and the membrane is kept in the pressure receiving liquid chamber. In response to the increase or decrease of the hydraulic pressure, it can be easily elastically deformed in the direction of volume expansion and contraction, and the increase in the hydraulic pressure in the pressure receiving liquid chamber due to the deformation of the elastic body is suppressed. The expansion elasticity of the pressure receiving liquid chamber with respect to the input vibration is reduced.

  As a result, when the elastic body is elastically deformed by vibrations other than idle vibration input from the vibration generating unit, that is, high-frequency vibrations such as booming noise and low-frequency vibrations such as shake vibrations, these vibrations are absorbed by the internal resistance of the elastic body. The At this time, since the dynamic spring constant of the pressure-receiving liquid chamber with respect to the high frequency vibration can be lowered by setting the membrane rigidity sufficiently low in advance to cope with the high frequency vibration, High frequency vibration can be effectively reduced. In addition, by providing a stopper to limit the elastic deformation of the membrane when low-frequency vibration such as shake vibration is input, a large hydraulic pressure is generated in the pressure-receiving liquid chamber along with the deformation of the elastic body even when low-frequency vibration with a large amplitude is input. A change occurs and the liquid forcibly moves back and forth between the pressure receiving liquid chamber and the sub liquid chamber through the restriction passage, so that the low frequency vibration can be absorbed and attenuated by the action of the viscous resistance of the liquid.

  Therefore, according to the vibration isolator of the present invention, one sub liquid chamber communicating with the pressure receiving liquid chamber through one restricting passage is provided, and a membrane for suppressing an increase in the liquid pressure is provided. It is possible to absorb and dampen high-frequency vibrations such as idle vibrations, booming sounds, and low-frequency vibrations such as shake vibrations, so that the secondary liquid that communicates with the pressure-receiving liquid chamber via the restriction passage. Compared with a vibration isolator provided with two or more chambers, the structure of the apparatus can be simplified and input vibrations in a wide frequency range including high frequency vibrations can be effectively absorbed.

  As described above, according to the vibration isolator of the present invention, it is possible to effectively absorb input vibrations in a wide frequency range including high frequency vibrations while simplifying the structure of the device.

  Hereinafter, a vibration isolator according to an embodiment of the present invention will be described with reference to the drawings.

  1 and 2 show a vibration isolator according to an embodiment of the present invention. The vibration isolator 10 is applied as an engine mount that supports an engine that is a vibration generating unit in an automobile to a vehicle body that is a vibration receiving unit. 1 and 2 indicate the axis of the apparatus, and the following description will be made assuming that the direction along the axis S is the axial direction of the apparatus.

  As shown in FIG. 1, the vibration isolator 10 includes a substantially cylindrical coupling metal 12 that is coupled to the engine via a bolt shaft 13, and a cup-shaped holder that is coupled to the vehicle body via a bolt shaft 15. 14, and an elastic body 16 that is disposed between the coupling fitting 12 and the holder 14 and serves as a main vibration absorber for input vibration. Here, the holder 14 includes a cylindrical outer cylinder 18 and a bottom plate 20 fixed by caulking so as to close a lower end portion of the outer cylinder 18. In the vibration isolator 10, a thick disk-like partition member 22 is fitted and fixed in the holder 14. In the partition member 22, a circular recess 24 is formed at the center of the upper surface, and a circular recess 26 is formed at the center of the lower surface. Further, in the vibration isolator 10, an outer peripheral portion of a rubber diaphragm 28 formed in a thin film shape is sandwiched between the lower surface of the partition member 22 and the bottom plate 20.

  The elastic body 16 is made of a rubber material such as NR or NBR, and is fixed to the upper end portions of the connection fitting 12 and the outer cylinder 18 by vulcanization adhesion or the like. The vibration isolator 10 is provided with a pressure receiving liquid chamber 30 in which a part of the inner wall is formed by the elastic body 16 and a sub liquid chamber 32 in which a part of the partition wall is formed by the diaphragm 28. The chamber 30 and the auxiliary liquid chamber 32 are connected by an idle orifice 34 that is a restriction passage formed in the partition member 22. Here, the pressure receiving liquid chamber 30, the sub liquid chamber 32, and the idle orifice 34 are filled with a liquid such as water or ethylene glycol, and the liquid passes through the idle orifice 34 between the pressure receiving liquid chamber 30 and the sub liquid chamber 32. Distribution is possible. The idle orifice 34 is set (tuned) so that its path length and cross-sectional area are adapted to idle vibration (20 Hz to 40 Hz).

  In the vibration isolator 10, a first air chamber 36 is provided between the bottom plate 20 and the diaphragm 28, and the first air chamber 36 has an air hole (perforated in the bottom plate 20 as necessary) ( It is communicated with the external space of the device through (not shown) or sealed from the external space of the device. The diaphragm 28 is provided with a first air chamber 36 adjacent to the sub liquid chamber 32, so that the inner volume of the sub liquid chamber 32 is expanded or contracted according to a change in the liquid pressure in the sub liquid chamber 32. It can be elastically deformed in the direction.

  In the vibration isolator 10, a clamping plate 38 is disposed so as to be in close contact with the entire upper surface of the partition member 22, and a rubber membrane formed in a disk shape is interposed between the clamping plate 38 and the partition member 22. 40 is sandwiched. The membrane 40 closes the recess 24 of the partition member 22. As a result, a second air chamber 42 adjacent to the pressure-receiving liquid chamber 30 is formed in the recess 24 via the membrane 40. The clamping plate 38 has a plurality of communication holes 44 facing the membrane 40, and the fluid pressure in the pressure receiving liquid chamber 30 acts on the membrane 40 through these communication holes 44. Here, the membrane 40 can be elastically deformed in the axial direction so as to expand and contract the internal volume of the pressure receiving liquid chamber 30 in accordance with a change in the liquid pressure in the pressure receiving liquid chamber 30.

  The vibration isolator 10 is provided with a communication path 46 having one end opened in the holder 14 and the other end opened to the outer peripheral surface of the outer cylinder 18 in the holder 14. One end of a pressure pipe 48 including a pipe, a pressure hose and the like is connected to the end through a nipple (not shown). The vibration isolator 10 is provided with a vacuum switching valve (hereinafter referred to as “VSV”) 50 connected to the second air chamber 42 via the communication passage 46 and the pressure pipe 48 outside the holder 14. The VSV 50 is constituted by a three-port electromagnetic valve, and the first port 51 is connected to the second air chamber 42 via the communication passage 46 and the pressure pipe 48. The VSV 50 has a second port 52 opened to the atmospheric space through a pipe 55 and a third port 53 connected to a negative pressure supply source 58 through a pipe 56. Here, the negative pressure supply source 58 includes, for example, a surge tank disposed in an intake passage for sucking air into the engine, a vacuum tank connected to the surge tank, and the like.

  The vibration isolator 10 is provided with a controller 60 for controlling the VSV 50 according to the frequency of the input vibration. The controller 60 determines the frequency of the input vibration. When the idle vibration (20 Hz to 40 Hz) is input, the VSV 50 causes the second air chamber 42 to communicate with the negative pressure supply source 58 and the idle vibration (20 Hz to 40 Hz) is not transmitted. At the time of input, that is, when high frequency vibration and low frequency vibration are input with respect to idle vibration, the second air chamber 42 is communicated with the atmospheric space by the VSV 50.

  Here, when the second air chamber 42 communicates with the negative pressure supply source 58, as shown in FIG. 2, the membrane 40 is moved into the second air chamber by the action of the negative pressure introduced into the second air chamber 42. Even when the fluid pressure in the pressure receiving fluid chamber 30 changes due to being adsorbed to the bottom surface portion of the membrane 42, the membrane 40 is restrained from elastic deformation. At this time, an auxiliary liquid chamber 62 partitioned from the pressure receiving liquid chamber 30 is formed by the holding plate 38 between the membrane 40 deformed into a concave shape and the holding plate 38, and the auxiliary liquid chamber 62 is formed on the holding plate 38. It communicates with the pressure receiving fluid chamber 30 through the drilled communication hole 44.

  Here, the flow resistance to the liquid through the communication hole 44 is set (tuned) so as to correspond to higher-order vibrations transmitted from the VSV 50 when negative pressure is introduced into the second air chamber 42. That is, when the communication destination of the second air chamber 42 is switched from the atmospheric space to the negative pressure supply source 58 by the VSV 50, a pressure wave having a substantially rectangular waveform is generated from the VSV 50 along with the port switching operation. High-order vibration of the pressure wave is transmitted to the membrane 40 through the pressure pipe 48 and the air in the second air chamber 42. The high-order vibration of the pressure wave is transmitted to the auxiliary liquid chamber 62 through the membrane 40 without being damped by the membrane 40, but the flow resistance to the liquid through the communication hole 44 is changed to the high-order vibration from the VSV 50. Tuned to accommodate. As a result, since the communication hole 44 functions as an orifice corresponding to higher-order vibration, liquid column resonance is caused between the auxiliary liquid chamber 62 and the pressure-receiving liquid chamber 30 through the communication hole 44 when high-order vibration is transmitted, This liquid column resonance can effectively absorb higher order vibrations from the VSV 50.

  Further, since the second air chamber 42 communicates with the atmospheric space, the inside of the second air chamber 42 is maintained at a substantially atmospheric pressure, and the membrane 40 can be easily expanded or contracted in accordance with a change in the liquid pressure in the pressure receiving liquid chamber 30. It is in a state where it can be elastically deformed. At this time, in the membrane 40, elastic deformation in the direction of expanding the volume of the pressure receiving fluid chamber 30 is limited by contacting the bottom surface portion of the second air chamber 42, and in the direction of reducing the volume of the pressure receiving fluid chamber 30. The elastic deformation is limited by contacting the clamping plate 38. That is, the bottom surface portion of the second air chamber 42 and the sandwiching plate 38 are each configured as a stopper that restricts excessive elastic deformation of the membrane 40. The membrane 40 is set to have low rigidity corresponding to high-frequency vibration such as a booming sound, and sufficient elastic deformation occurs due to a change in the hydraulic pressure generated in the pressure receiving liquid chamber 30 when high-frequency vibration is input.

  Next, the operation of the vibration isolator 10 according to the present embodiment configured as described above will be described. In the vibration isolator 10, when the idle vibration is input, the controller 60 introduces the negative pressure from the negative pressure supply source 58 into the second air chamber 42 by the VSV 50, thereby introducing the negative pressure introduced into the second air chamber 42. Since the membrane 40 is adsorbed to the bottom surface portion of the second air chamber 42 by the action of pressure, the membrane 40 is restrained from elastic deformation even if the fluid pressure in the pressure receiving fluid chamber 30 changes. A decrease in the expansion elasticity of the pressure receiving liquid chamber 30 due to the elastic deformation of the membrane 40 is prevented.

  As a result, when the elastic body 16 is elastically deformed by idle vibration (20 Hz to 40 Hz) input from the engine that is the vibration generating unit, the idle vibration is absorbed by the internal resistance of the elastic body 16 and at the same time, the elastic deformation of the elastic body 16 is performed. As the liquid flows between the pressure-receiving liquid chamber 30 and the sub liquid chamber 32 whose internal volume changes (expands / contracts) along with the idle orifice 34 which is a restriction passage, the liquid viscous resistance and liquid column resonance It is possible to effectively absorb and damp idle vibration by the action of.

  FIG. 3 shows the relationship between the vibration frequency and the dynamic spring constant K in the vibration isolator 10 when idling vibration is input. In the vibration isolator 10, the negative pressure is introduced into the second air chamber 42 when the idle vibration (20 Hz to 40 Hz) is input to restrain the membrane 40, so that the pressure receiving liquid chamber 30 and the sub liquid chamber 32 are passed through the idle orifice 34. As shown in FIG. 3, the dynamic spring constant K with respect to the idle vibration of 20 Hz to 40 Hz can be kept sufficiently low, and the damping with respect to the idle vibration is greatly attenuated. An effect can be obtained.

  Further, in the vibration isolator 10 according to the present embodiment, when the idle vibration is not input, the controller 60 causes the VSV 50 to communicate the second air chamber 42 with the atmospheric space, thereby maintaining the inside of the second air chamber 42 at substantially atmospheric pressure. Accordingly, the membrane 40 can be easily elastically deformed in the volume expansion / contraction direction according to the change in the liquid pressure in the pressure receiving liquid chamber 30, and the increase in the liquid pressure in the pressure receiving liquid chamber 30 due to the deformation of the elastic body 16 is suppressed. Therefore, the expansion elasticity of the pressure receiving liquid chamber 30 with respect to the input vibration is reduced as compared with the case of inputting the idle vibration.

  As a result, when the elastic body 16 is elastically deformed by vibrations other than idle vibration input from the engine, that is, high-frequency vibrations such as booming noise and low-frequency vibrations such as shake vibrations, these vibrations are absorbed by the internal resistance of the elastic body 16. The At this time, since the stiffness of the membrane 40 is set sufficiently low corresponding to the high frequency vibration, the dynamic spring constant of the pressure receiving liquid chamber 30 with respect to the high frequency vibration can be lowered. Can effectively reduce high-frequency vibrations.

  FIG. 4 shows the relationship between the vibration frequency and the dynamic spring constant Kd in the vibration isolator 10 when high-frequency vibration is input. As is apparent from FIG. 4, the second air chamber 42 communicates with the atmospheric space. By allowing the membrane 40 to be released, it is possible to prevent the dynamic spring constant Kd from increasing when high frequency vibration of about 100 Hz to 200 Hz is input, so that a sufficient damping effect is obtained even for high frequency vibration. be able to.

  Further, when low frequency vibration such as shake vibration is input, elastic deformation of the membrane 40 is limited by the sandwiching plate 38 functioning as a stopper and the bottom surface of the second air chamber 42. Therefore, when low frequency vibration having a large amplitude is input. In addition, since the elastic body 16 is deformed, a large fluid pressure change occurs in the pressure receiving liquid chamber 30 and the liquid is forcibly transferred between the pressure receiving liquid chamber 30 and the sub liquid chamber 32 through the idle orifice 34. Low frequency vibration can be absorbed and damped by the action of viscous resistance.

  FIG. 5 shows the relationship between the vibration frequency and the dynamic spring constant in the vibration isolator 10 when low-frequency vibration is input. In the figure, the solid line indicates that negative pressure is introduced into the second air chamber 42. The dynamic spring constant δ1 when the membrane 40 is constrained is shown, and the broken line shows the dynamic spring constant δ2 when the second air chamber 42 communicates with the atmospheric space. As apparent from FIG. 5, the second air chamber 42 is communicated with the atmospheric space, and the elastic deformation of the membrane 40 is limited by the sandwiching plate 38 and the bottom surface portion of the second air chamber 42. Compared with the case where negative pressure is introduced into 42, the dynamic spring constant of the pressure receiving liquid chamber 30 for low frequency vibration (shake vibration) of about 10 Hz to 20 Hz can be maintained at a sufficiently low level. A constant attenuation effect can be obtained.

  Therefore, according to the vibration isolator 10 according to the present embodiment, one sub liquid chamber communicating with the pressure receiving liquid chamber 30 through one idle orifice 34 is provided, and a membrane for suppressing an increase in the hydraulic pressure is provided. It is possible to absorb and dampen low frequency vibrations such as idle vibration, high-frequency vibration such as booming noise, and low-frequency vibration such as shake vibration simply by providing 40 so as to face the pressure receiving liquid chamber 30. Compared with a conventional vibration isolator provided with two or more sub liquid chambers communicating with the liquid chamber, the structure of the device can be simplified and input vibrations in a wide frequency range including high frequency vibrations can be effectively absorbed.

It is sectional drawing which shows the structure of the vibration isolator which concerns on embodiment of this invention, and has shown the state which the 2nd air chamber is connected to atmospheric space. It is sectional drawing which shows the structure of the vibration isolator which concerns on embodiment of this invention, and is sectional drawing which shows the state in which the negative pressure is introduce | transduced in the 2nd air chamber. 2 is a graph showing the relationship between a vibration frequency and a dynamic spring constant K when an idle vibration is input in the vibration isolator shown in FIG. 1. It is a graph which shows the relationship between the vibration frequency at the time of the high frequency vibration input in the vibration isolator shown in FIG. 1, and the dynamic spring constant Kd. It is a graph which shows the relationship between the vibration frequency at the time of the low frequency vibration input in the vibration isolator shown in FIG. 1, and a dynamic spring constant. It is sectional drawing which shows the structure of the conventional liquid enclosure type vibration isolator.

Explanation of symbols

10 Vibration isolator 12 Connecting bracket (first mounting member)
14 Holder (second mounting member)
16 Elastic body 30 Pressure receiving liquid chamber 32 Sub liquid chamber 34 Idle orifice 38 Nipping plate (stopper)
40 Membrane 42 Second air chamber (air chamber)
44 Communication hole (orifice)
50 Vacuum switching valve 58 Negative pressure supply source 60 Controller 62 Auxiliary liquid chamber

Claims (2)

A first attachment member coupled to one of the vibration generator and the vibration receiver;
A second attachment member coupled to the other of the vibration generating portion and the vibration receiving portion;
An elastic body disposed between the first mounting member and the second mounting member, and elastically deformed by input vibration from a vibration generating unit;
A pressure receiving liquid chamber whose internal volume is expanded and contracted by deformation of the elastic body with the elastic body as a part of the partition;
A limit passage for absorbing idle vibration, one end of which is connected to the pressure-receiving liquid chamber;
The other end of the restriction passage is connected, and a sub liquid chamber in which liquid flows back and forth so as to resonate with the idle vibration through the restriction passage when the idle vibration is input,
A membrane that constitutes another part of the partition wall in the pressure-receiving liquid chamber and is elastically deformable in an expansion / contraction direction that expands / contracts the internal volume of the pressure-receiving liquid chamber;
An air chamber disposed adjacent to the pressure-receiving liquid chamber via the membrane;
A vacuum switching valve for communicating the air chamber with either a negative pressure supply source or an atmospheric space;
Control means for introducing a negative pressure from a negative pressure supply source into the air chamber by the vacuum switching valve at the time of input of idle vibration, and communicating the air chamber to the atmospheric space by the vacuum switching valve at the time of non-input of idle vibration;
A stopper that restricts elastic deformation along the expansion / contraction direction of the membrane and has an orifice drilled to face the pressure receiving liquid chamber and the membrane,
Have
When introducing negative pressure into the air chamber, an auxiliary liquid chamber partitioned from the pressure receiving liquid chamber is formed between the stopper and the membrane, and between the pressure receiving liquid chamber and the auxiliary liquid chamber through the orifice. The liquid can flow mutually, and the flow resistance of the liquid in the orifice hole is set so as to correspond to higher-order vibration transmitted from the vacuum switching valve when negative pressure is introduced into the air chamber. Anti-vibration device. An outer cylinder member in which the pressure receiving liquid chamber and the sub liquid chamber are provided;
A partition member that is inserted into the outer cylinder member and divides a space in the outer cylinder member into the pressure receiving liquid chamber and the sub liquid chamber;
2. The vibration isolator according to claim 1, wherein the air chamber and the secondary liquid chamber are formed in the partition member.

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