JP2011027157A - Vibration control device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a vibration control device capable of keeping a vibration control effect by a simple structure in a wider vibration frequency band. <P>SOLUTION: In the vibration control device 10, a dynamic spring constant of a fluid chamber switching member 60 is switched autonomously by an increase in a frequency of input vibration over a resonance frequency of the fluid chamber switching member 60. Therefore, by the increase in the frequency of the input vibration, the vibration frequency band capable of keeping the dynamic spring constant of the vibration control device 10 low can be shifted to a high frequency side. As a result, even when vibration in a frequency band higher than a lockup booming noise vibration (a booming noise vibration in acceleration) is input, the dynamic spring constant can be kept low and the vibration control effect can be obtained effectively. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a vibration isolator that is used as an engine mount or the like in a general industrial machine or an automobile and absorbs and attenuates vibration transmitted from a vibration generating unit such as an engine to a vibration receiving unit such as a vehicle body.

  For example, an anti-vibration device as an engine mount is disposed between an engine that is a vibration generation unit of a vehicle and a vehicle body that is a vibration receiving unit, and the anti-vibration device absorbs vibration generated by the engine, Suppresses vibration transmission to the vehicle body. As such an anti-vibration device, a liquid-sealed device is known in which an elastic body and a pair of liquid chambers are provided inside the device, and the pair of liquid chambers communicate with each other through a restriction passage. According to this liquid-sealed vibration isolator, it is possible to obtain a vibration damping effect and a vibration isolating effect by elastic deformation of the elastic body and liquid column resonance of the liquid in the orifice communicating between the pair of liquid chambers. it can.

  As the conventional liquid-filled vibration isolator as described above, a vibration isolator having a plurality of orifices has been developed. Typically, the plurality of orifices are tuned to accommodate different frequencies. Therefore, liquid column resonances in the orifices occur in different frequency bands in different orifices (for example, in the shake orifice frequency band and in the idle orifice idle vibration frequency band). For this reason, as compared with a vibration isolator having only a single orifice, attenuation can be obtained in a wide frequency band, and the dynamic spring constant can also be lowered in a wide frequency band (see Patent Document 1). .

  By the way, even when the vehicle is traveling, the vibration frequency is different between the case where the vehicle is traveling at a constant speed and the case where the vehicle is accelerating. In other words, when running at a constant speed, the engine speed is relatively suppressed. However, especially in the case where fuel efficiency is emphasized, high geared running is performed at a low engine speed, so engine vibration increases and so-called lock-up occurs. A booming sound vibration occurs. On the other hand, at the time of acceleration traveling, the engine speed increases, and a higher-frequency acceleration noise is generated during acceleration.

JP-A-9-10086

  The object of the present invention has been made in consideration of the above facts, and an object thereof is to provide a vibration isolator capable of maintaining a vibration isolating effect even at a constant speed and during acceleration.

  In order to achieve the above object, a vibration isolator according to claim 1 of the present invention is a vibration isolator for an engine of a vehicle, and includes a first mounting member coupled to one of the engine and the vehicle body, and the engine and the vehicle body. A second mounting member connected to the other of the first mounting member, an elastic body disposed between the first mounting member and the second mounting member, and the elastic body configured as a part of the partition wall, A main liquid chamber in which liquid is sealed, a sub liquid chamber in which liquid is sealed and at least a part of the partition wall is configured by a diaphragm, and can be expanded or contracted according to a change in liquid pressure, and a movable that can be displaced by a change in liquid pressure A wall member as a part of the partition wall, a partition member that partitions the main liquid chamber and the sub liquid chamber, and a first restriction passage that is configured in the partition member and communicates the main liquid chamber and the sub liquid chamber Between the movable wall member and the movable wall member. An intermediate chamber member that constitutes an intermediate liquid chamber, the intermediate liquid chamber and the main liquid chamber, or a second restriction passage that communicates the intermediate liquid chamber and the sub liquid chamber, and the intermediate liquid chamber. A fluid chamber in which a fluid is sealed, an intermediate movable film that partitions the intermediate liquid chamber and the fluid chamber, and a part of a partition wall of the fluid chamber that moves according to a change in internal pressure of the fluid chamber A fluid chamber partition that can be installed, and a support elastic member that elastically supports the fluid chamber partition, and the second restriction in a state in which the fluid chamber partition is moved according to an internal pressure of the fluid chamber. A fluid chamber switching member having a resonance frequency set to a frequency higher than the resonance frequency of the passage.

  In the vibration isolator having the above configuration, the fluid chamber is configured adjacent to the intermediate liquid chamber. Between the intermediate liquid chamber and the fluid chamber, an intermediate movable film that partitions both is disposed. Further, the fluid chamber is configured such that a fluid chamber partition wall that can move according to a change in the internal pressure of the fluid chamber is a part of the partition wall, and the fluid chamber partition wall is elastically supported by a support elastic member.

  Here, the supporting elastic member has a specific resonance frequency according to the mass of the fluid chamber partition that is supported. When the input vibration is a frequency lower than the resonance frequency, the support elastic member is elastically deformed in response to the vibration input to the fluid chamber. Therefore, the intermediate movable film can vibrate without being restrained from the fluid chamber side.

  On the other hand, when the input vibration becomes a frequency higher than the resonance frequency, the dynamic spring constant of the supporting elastic member becomes high due to anti-resonance, and the elastic deformation becomes difficult. And even if a vibration is input into the fluid chamber, the supporting elastic member is hardly elastically deformed. Therefore, the fluid chamber partition wall is difficult to move, and the intermediate movable film is restrained from the fluid chamber side.

  In the present invention, the resonance frequency of the fluid chamber switching member is set to a frequency higher than the resonance frequency of the second restriction passage when the fluid chamber partition wall is moved according to the internal pressure of the fluid chamber. As described above, when the frequency of the input vibration becomes higher than the resonance frequency of the fluid chamber switching member, the fluid chamber partition wall becomes less likely to move autonomously, and the intermediate movable wall is restrained. Shifts to the high frequency side. Thereby, compared with the case where a fluid chamber switching member is not provided, the dynamic spring constant of the vibration isolator can be kept low even for higher frequency vibration inputs.

  The vibration isolator according to claim 2 of the present invention is characterized in that the supporting elastic member includes a spring member.

  As described above, the elastic elastic member can be configured by using the spring member to support the fluid chamber partition wall at one end of the spring member and fixing the other end to the second mounting member side.

  The vibration isolator according to claim 3 of the present invention is characterized in that air is sealed in the fluid chamber.

  Thus, the fluid chamber can be easily configured by using air as the fluid sealed in the fluid chamber.

  The vibration isolator according to claim 4 of the present invention is characterized in that the side of the fluid chamber partition opposite to the fluid chamber is open to atmospheric pressure.

  In this way, by opening the opposite side of the fluid chamber partition wall from the fluid chamber to atmospheric pressure, the fluid chamber switching member can be operated in accordance with its characteristics.

  In the vibration isolator according to claim 5 of the present invention, the first restricting passage corresponds to vibration of a frequency band of 5 Hz to 15 Hz, and the second restricting passage is configured such that the fluid chamber is expanded or contracted according to the fluid pressure. In the case of a state, it is comprised so that it may respond | correspond to the vibration of a frequency band 40Hz-60Hz.

  As described above, by setting the first restriction passage and the second restriction passage, the second restriction passage is used to attenuate vibrations in the frequency band 5 Hz to 15 Hz and high frequency vibrations in the frequency band 40 Hz to 60 Hz. Can do.

  As described above, according to the present invention, it is possible to maintain the vibration isolation effect in a wider vibration frequency band.

FIG. 4 is a side sectional view taken along the line II in FIG. 3 of the vibration isolator according to the embodiment of the present invention. FIG. 4 is a side sectional view taken along the line II-II in FIG. 3 of the vibration isolator according to the embodiment of the present invention. It is III-III sectional drawing in FIG. 1 of the vibration isolator which concerns on embodiment of this invention. It is a disassembled perspective view which shows the structure of the partition member, intermediate | middle chamber member, fluid chamber switching member, and fluid chamber member of the vibration isolator which concerns on embodiment of this invention. It is a schematic diagram of the vibration isolator which concerns on embodiment of this invention. It is a graph which shows the dynamic spring characteristic of the vibration isolator which concerns on embodiment of this invention. It is side surface sectional drawing which shows the structure of the vibration isolator which concerns on the modification of embodiment of this invention. It is a schematic diagram of the vibration isolator which concerns on the modification of embodiment of this invention.

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

  FIG. 1 shows a vibration isolator 10 according to an embodiment of the present invention. The vibration isolator 10 is applied as an engine mount that supports an automobile engine on a vehicle body. Note that the symbol S in the figure indicates the axis of the apparatus, the direction along the axis is the axis direction S of the apparatus, and the vertical direction in the figure is the vertical direction of the vibration isolator 10 in the following description. Main vibration (main vibration) for the purpose of vibration isolation is input in the axial direction S.

  As shown in FIG. 1, the vibration isolator 10 includes a first attachment member 14 and a second attachment member 12.

  The 2nd attachment member 12 is made into a substantially cylindrical shape, and the concave step part 12A is comprised in the one end part. A crimped portion 12 </ b> C that is crimped radially inward is formed at the other end of the second mounting member 12. A partition pinching portion 12B is formed between the concave step portion 12A and the caulking portion 12C. The second mounting member 12 is connected to the vehicle body via a bracket (not shown).

  The first mounting member 14 is disposed on the radial inner side of the second mounting member 12 and on the upper side of the second mounting member 12 in the axial direction S when viewed from the axial direction S. The elastic body connecting portion 14A, the flange portion 14B, And the bracket insertion part 14C is provided. 14 A of elastic body connection parts are made into the truncated cone shape which becomes a small diameter below. The flange portion 14B has a disk shape projecting radially outward from the upper portion of the elastic body connecting portion 14A. The bracket insertion portion 14C is formed in a cylindrical shape having a smaller diameter than the flange portion 14B, extends upward from the flange portion 14B, and has a screw hole 14D in which a female screw is formed from the upper surface central portion toward the lower side in the axial direction. ing. A bolt (not shown) for connecting to the engine side bracket is screwed into the screw hole 14D. The first mounting member 14 is connected to the engine via a bracket on the engine side.

  The first mounting member 14 and the second mounting member 12 are arranged so as to be coaxial with each other. These axes are the axial direction S of the vibration isolator 10.

  Between the first mounting member 14 and the second mounting member 12, a rubber elastic body 16 serving as a main vibration absorber is disposed. The elastic body 16 is vulcanized and bonded from the outer surface of the elastic body connecting portion 14A of the first mounting member 14 to the lower surface of the flange portion 14B, and vulcanized and bonded to the radially inner side surface of the recessed step portion 12A of the second mounting member 12. Has been. The first attachment member 14 and the second attachment member 12 are elastically connected by the elastic body 16.

  The elastic body 16 is integrally formed with a thin film-like covering portion 18 extending downward from the lower end portion thereof. The covering portion 18 is vulcanized and bonded to the inner peripheral surfaces of the partition holding portion 12B and the caulking portion 12C of the second mounting member 12 to cover the inner wall of the second mounting member 12. A step portion 12E is formed in a portion corresponding to the space between the recessed step portion 12A of the covering portion 18 and the partition holding portion 12B. A positioning member 20 described later is brought into contact with the stepped portion 12E for positioning.

  The elastic body 16 is integrally formed with a stopper rubber portion 16A that extends upward from the upper end portion thereof and covers the outer peripheral surface and the upper surface of the flange portion 14B. The stopper rubber portion 16A hits a stopper fitting (not shown) disposed outside the elastic body 16 and the first mounting member 14, so that the first mounting member 14 and the second mounting member 12 at the time of large vibration input. Regulate the amount of relative movement.

  A partition member 20 is disposed on the inner peripheral side of the covering portion 18. As shown in FIGS. 3 and 4, the partition member 20 is annular, and a spiral groove M is formed on the outer periphery. Between this groove | channel M and the coating | coated part 18, the 1st restriction | limiting channel | path 40 which connects the main liquid chamber 50 mentioned later and the subliquid chamber 52 is comprised. The first restriction passage 40 communicates with the main liquid chamber 50 through the communication portion 20A, and communicates with the sub liquid chamber 52 through the communication portion 20B.

  A hollow is formed on the inner peripheral side of the partition member 20, and a circular opening 22 is formed on the upper side of the hollow. The opening 22 is closed with a membrane 24. The membrane 24 has a disk shape and partitions a main liquid chamber 50 and an intermediate liquid chamber 58 which will be described later. The membrane 24 can be made of an elastic material such as rubber or thermoplastic elastomer (TPE).

  As shown in FIG. 4, a gas hole 21 extending from the hollow to the radially outer side is drilled in a portion where the groove M of the partition member 20 is not configured.

  A step portion 26 having a large diameter on the lower side is formed in the middle portion of the inner peripheral wall of the partition member 20. An intermediate chamber member 30 is fitted into the hollow lower side on the inner peripheral side of the partition member 20. Details of the intermediate chamber member 30 will be described later.

  A ring 54 is disposed on the inner peripheral side of the covering portion 18 below the partition member 20. An outer peripheral portion of a thin film rubber diaphragm 56 is vulcanized and bonded to the inner peripheral surface of the ring 54 so as to close the inside of the ring 54. The partition member 20 is inserted into the second mounting member 12 so as to be in contact with the step portion 26, and the ring 54 is inserted into the second mounting member 12 so as to be in contact with the partition member 20. Yes. As for the 2nd attachment member 12, the crimping part 12C is crimped to the inner peripheral side. Thereby, the partition member 20 and the ring 54 are fixed in the second attachment member 12. In this state, the ring 54 is pressed against the inner peripheral wall of the second mounting member 12 via the covering portion 18, and the space inside the second mounting member 12 and the elastic body 16 is sealed from the outside by the diaphragm 56. Has been. A liquid L such as water or oil is enclosed in the sealed space. This sealed space is partitioned by the partition member 20 into a main liquid chamber 50 on the elastic body 16 side and a sub liquid chamber 52 on the diaphragm 56 side.

  The main liquid chamber 50 is configured with the elastic body 16 and the partition member 20 as partitions inside the second mounting member 12. The main liquid chamber 50 is filled with the liquid L. The auxiliary liquid chamber 52 is configured with the diaphragm 56 and the partition member 20 as a partition inside the second mounting member 12. The sub liquid chamber 52 is filled with the liquid L. The diaphragm 56 is deformed by a change in the hydraulic pressure in the sub liquid chamber 52, and the sub liquid chamber 52 can be expanded and contracted.

  As shown in FIG. 4, the intermediate chamber member 30 is formed in an annular shape, and a circumferential groove 33 is formed along the outer edge portion with the lower side open. The circumferential groove 33 includes a communication hole 33A on the upper side of one end. A hollow 31 is formed at the center of the intermediate chamber member 30, and the upper end side is closed with a membrane 32. As shown in FIG. 3, a wall portion 35 is formed between the end portions of the circumferential groove 33. A gas communication groove 35 </ b> A that extends radially outward from the hollow 31 is formed below the wall portion 35. The gas communication groove 35 </ b> A is configured at a position corresponding to the gas hole 21 of the partition member 20.

  An intermediate liquid chamber 58 is formed between the intermediate chamber member 30 and the membrane 24 (see FIG. 1). The intermediate liquid chamber 58 is configured to be surrounded by the membrane 24, the inner wall of the partition member 20, and the intermediate chamber member 30, and is filled with the liquid L as with the main liquid chamber 50 and the sub liquid chamber 52. The intermediate liquid chamber 58 is communicated with the sub liquid chamber 52 via a second restriction passage 42 described later. Between the circumferential groove 33 and the hollow 31 of the intermediate chamber member 30, a peripheral partition wall 34 that is convex from the upper surface of the intermediate chamber member 30 downward is formed. The length of the circumferential partition 34 in the axial direction S is shorter than the length of the outer peripheral wall of the circumferential groove 33 in the axial direction S.

  The fluid chamber member 36 has a flat plate-shaped bottom portion 37 and a cylindrical tube portion 38 formed on the top of the bottom portion 37. The outer diameter of the bottom portion 37 is substantially the same as the outer diameter of the circumferential groove 33, and the outer diameter of the cylindrical portion 38 is substantially the same as the diameter of the hollow 31. Further, the height of the cylindrical portion 38 is shorter than that of the peripheral partition wall 34. A support elastic member 62 is disposed inside the cylindrical portion 38. The support elastic member 62 is configured by a coil spring, and one end is fixed on the bottom portion 37.

  A fluid chamber partition wall 64 is disposed on the distal end side of the tubular portion 38 so as to cover the opening of the tubular portion 38. The fluid chamber partition wall 64 includes a ring member 64C, a moving plate 64A, and a peripheral end connecting portion 64B. The ring member 64 </ b> C has an annular shape, and the outer diameter is substantially the same as the diameter of the hollow 31. The moving plate 64A has a disc shape, has an outer diameter smaller than the inner diameter of the ring member 64C, and is arranged on the radially inner side of the ring member 64C. The moving plate 64A and the ring member 64C are connected by a rubber peripheral end connecting portion 64B. The moving plate 64A is movable in the axial direction S by elastic deformation of the peripheral end connecting portion 64B.

  The other end of the support elastic member 62 is fixed to the moving plate 64 </ b> A of the fluid chamber partition wall 64. The fluid chamber partition wall 64 is elastically supported by the support elastic member 62. The support elastic member 62 and the fluid chamber partition wall 64 constitute a fluid chamber switching member 60.

  The fluid chamber partition wall 64 is fitted into the hollow 31 so that the outer periphery of the ring member 64 </ b> C is in close contact with the inner wall of the peripheral partition wall 34. The fluid chamber member 36 is engaged with the intermediate chamber member 30 with the cylindrical portion 38 fitted in the hollow 31 from the lower side of the fluid chamber partition wall 64 and the bottom portion 37 fitted inside the circumferential groove 33. Thereby, the lower side of the circumferential groove 33 and the hollow 31 is closed, and the second restriction passage 42 is configured at a position corresponding to the circumferential groove 33. The second restriction passage 42 communicates with the intermediate liquid chamber 58 through the communication hole 33A, and communicates with the sub liquid chamber 52 through the communication hole 37B.

  A fluid chamber 39 is formed between the membrane 32 and the fluid chamber partition wall 64 at a position corresponding to the hollow 31. The fluid chamber 39 is partitioned from the intermediate liquid chamber 58 by the membrane 32 and is filled with air. Further, an atmospheric pressure chamber 66 is formed between the fluid chamber partition wall 64 and the bottom portion 37 at a position corresponding to the hollow 31.

  The cylinder portion 38 of the fluid chamber member 36 includes an atmospheric communication portion 38 </ b> A that communicates with the atmospheric pressure chamber 66. The air communication portion 38A is configured at a position corresponding to the gas communication groove 35A of the intermediate chamber member 30. A gas communication hole 35H is formed between the fluid chamber member 36 and the gas communication groove 35A.

  As shown in FIG. 1, the atmospheric pressure chamber 66 </ b> A, the gas communication hole 35 </ b> H, and the gas hole 21 are communicated, and the atmospheric pressure chamber 66 is atmospheric pressure via the hole 12 </ b> H drilled in the second mounting member 12. It is open to.

  FIG. 5 schematically shows the vibration isolator 10 having the above-described configuration. The vibration isolator 10 of this embodiment can be shown as shown in FIG.

  Referring briefly to FIG. 5, the liquid chamber surrounded by the second mounting member 12, the elastic body 16, and the diaphragm 56 is divided into a main liquid chamber 50 and a sub liquid chamber 52 by the partition member 20. . The main liquid chamber 50 and the sub liquid chamber 52 communicate with each other through the first restriction passage 40. Between the main liquid chamber 50 and the sub liquid chamber 52, an intermediate liquid chamber 58 is provided in parallel with the first restriction passage 40. The intermediate liquid chamber 58 is closed by the membrane 24 on the main liquid chamber 50 side. A second restriction passage 42 is formed between the main liquid chamber 50 and the sub liquid chamber 52 in series with the membrane 24 and closer to the sub liquid chamber 52 than the membrane 24. A part of the wall constituting the intermediate liquid chamber 58 is constituted by the membrane 32, and the side opposite to the intermediate liquid chamber 58 of the membrane 32 is a fluid chamber 39. A part of the wall constituting the fluid chamber 39 is constituted by a fluid chamber partition wall 64, and the opposite side of the fluid chamber partition wall 64 from the fluid chamber 39 is an atmospheric pressure chamber 66. A support elastic member 62 is disposed in the atmospheric pressure chamber 66.

  Next, the tuning of the first restriction passage 40, the second restriction passage 42, the membrane 32, and the fluid chamber switching member 60 will be described.

  When vibration in the axial direction S is input from the side of the first mounting member 14 connected to the engine, the elastic body 16 is elastically deformed, and the internal volume of the main liquid chamber 50 is expanded and contracted along with this elastic deformation. The first restriction passage 40 is tuned so as to cope with a large amplitude shake vibration in a relatively low frequency range of the input vibration in the axial direction S from the first mounting member 14 side. That is, when the shake vibration is input, the liquid L sealed in the main liquid chamber 50 and the liquid L sealed in the sub liquid chamber 52 due to the pressure difference between the main liquid chamber 50 and the sub liquid chamber 52 are transferred to the first restriction passage. It is set so that a vibration damping effect can be obtained by the liquid column resonance action in the first restriction passage 40 and the like. For example, the first restriction passage 40 can be set so that its path length and cross-sectional area are adapted to shake vibration input with an amplitude of ± 0.5 mm or more and a frequency band of 5 Hz to 15 Hz.

  In the state where the fluid chamber partition wall 64 is moved according to the internal pressure of the fluid chamber 39, the second restriction passage 42 has a higher frequency range than the shake vibration in the input vibration in the axial direction S from the first mounting member 14 side. The liquid L enclosed in the main liquid chamber 50 elastically deforms the membrane 24 due to a change in the liquid pressure in the main liquid chamber 50, and the intermediate liquid chamber 58 is tuned to cope with the lockup boom noise. Scale up and down. Then, the liquid L flows between the intermediate liquid chamber 58 and the sub liquid chamber 52 through the second restriction passage 42, and a vibration isolation effect is obtained by the liquid column resonance action in the second restriction passage 42. It is set to be able to. For example, in the state where the fluid chamber partition wall 64 is moved according to the internal pressure of the fluid chamber 39, the second restriction passage 42 is a lock having a path length and a cross-sectional area of about ± 0.05 mm in amplitude and a frequency band of 40 Hz to 60 Hz. Can be set to match the input of up-lifting vibration.

  The fluid chamber switching member 60 has a resonance frequency set at a frequency slightly higher than the lockup boom noise vibration in the input vibration in the axial direction S from the first mounting member 14 side. As a result, the fluid chamber partition wall 64 is moved according to the internal pressure of the fluid chamber 39 when a vibration below the resonance frequency is input, and the membrane 32 behaves in the same manner as when the fluid chamber 39 is open to the atmosphere.

  On the other hand, the fluid chamber switching member 60 is a dynamic spring constant due to anti-resonance for vibration input of vibration in a frequency band higher than the resonance frequency, for example, vibration input of acceleration sound during acceleration (frequency band 60 Hz to 150 Hz). Becomes higher. Therefore, at the time of vibration input in a frequency band higher than the resonance frequency, the movement of the fluid chamber partition wall 64 is restrained (the expansion elasticity of the fluid chamber partition wall 64 is increased), and the fluid chamber 39 is similar to the sealed state. As a result, the movement of the membrane 32 is also restricted, the characteristics of the second restriction passage 42 are shifted to the high frequency side, and when the humming noise vibration during acceleration is input, between the intermediate liquid chamber 58 and the sub liquid chamber 52, The liquid L is circulated through the second restricting passage 42 so that a vibration isolation effect can be obtained by a liquid column resonance action in the second restricting passage 42.

  Next, the operation and action of the vibration isolator 10 according to the present embodiment will be described.

  In the vibration isolator 10 of the present embodiment, vibration from the automobile engine is supported on the vehicle body via the first mounting member 14, the elastic body 16, and the second mounting member 12.

  When a relatively low frequency and large amplitude shake vibration (frequency 5 to 15 Hz, amplitude ± 0.5 mm or more) is input, the elastic body 16 is elastically deformed and the main liquid chamber 50 expands and contracts, and the liquid L passes through the first restriction passage. The vibration control effect can be obtained by going back and forth between the main liquid chamber 50 and the sub liquid chamber 52 via 40 and by a liquid column resonance action inside the first restriction passage 40.

  During normal running (non-acceleration), the first restriction passage 40 is clogged when a lock-up boom sound vibration (frequency 40 to 60 Hz, amplitude ± 0.05 mm) is input. On the other hand, the membrane 24 is elastically deformed according to the change in the hydraulic pressure in the main liquid chamber 50, and the liquid L flows through the opening 22. As a result, the fluid pressure in the intermediate fluid chamber 58 also changes, and the second restriction passage tuned to match the lockup boom noise vibration in a state where the fluid chamber partition wall 64 is moved in accordance with the internal pressure of the fluid chamber 39. The liquid L moves back and forth between the intermediate liquid chamber 58 and the sub liquid chamber 52 via 42, and a vibration isolation effect can be obtained by the liquid column resonance action inside the second restriction passage 42.

  When high-frequency, small-amplification acceleration sound vibration (frequency 60 Hz to 150 Hz, amplitude ± 0.05 mm or less) is input, the dynamic spring constant of the fluid chamber switching member 60 increases, and the fluid chamber 39 is in a sealed state. Become. As a result, the movement of the membrane 32 is also constrained, and the characteristics of the second restriction passage 42 are shifted so as to match the acceleration sound during vibration (frequency 60 Hz to 150 Hz, amplitude ± 0.05 mm or less). As a result, even when the acceleration noise is input, the liquid L moves back and forth between the intermediate liquid chamber 58 and the sub liquid chamber 52 via the second restricting passage 42, and the liquid inside the second restricting passage 42. An anti-vibration effect can be obtained by column resonance action or the like.

  FIG. 6 shows a graph showing the relationship between the vibration frequency input to the vibration isolator 10 and the dynamic spring constant of the vibration isolator 10. A solid line A indicates the characteristics of the vibration isolator 10 in a state where the fluid chamber partition wall 64 is moved according to the internal pressure of the fluid chamber 39, and a one-dot chain line B indicates the vibration isolator 10 in a state where the movement of the fluid chamber partition wall 64 is restricted. The characteristics are shown.

  In the vibration isolator 10 of the present embodiment, the dynamic spring constant of the fluid chamber switching member 60 is autonomously switched when the frequency of the input vibration becomes higher than the resonance frequency of the fluid chamber switching member 60. Therefore, the dynamic spring constant is switched from A to B in FIG. 6 by increasing the frequency of the input vibration. Thereby, the vibration frequency band which can maintain the dynamic spring constant of the vibration isolator 10 low can be shifted to the high frequency side. As a result, even when a vibration in a frequency band higher than the lock-up booming sound vibration (a booming noise vibration during acceleration) is input, the dynamic spring constant can be kept low and an effective vibration-proofing effect can be obtained.

  As described above, in the present embodiment, the fluid chamber switching member 60 is used to switch the characteristics of the second restricting passage 42 so that the dynamic spring constant can be kept low in a wider frequency band, and a vibration isolation effect can be obtained. it can.

  In the present embodiment, the membrane 24 is disposed between the main liquid chamber 50 and the intermediate liquid chamber 58. However, as shown in FIGS. 7 and 8, a movable plate 23 is disposed in place of the membrane 24. Also good.

  In the present embodiment, air is sealed in the fluid chamber 39, but is not limited to air, other gases may be sealed, and a liquid similar to the main liquid chamber 50 may be sealed. .

DESCRIPTION OF SYMBOLS 10 Vibration isolator 12 2nd attachment member 14 1st attachment member 16 Elastic body 20 Partition member 23 Movable plate 24 Membrane 30 Middle chamber member 32 Membrane 36 Fluid chamber member 37 Bottom part 39 Fluid chamber 40 First restriction passage 42 Second restriction passage 50 Main liquid chamber 52 Sub liquid chamber 56 Diaphragm 58 Intermediate liquid chamber 60 Fluid chamber switching member 62 Support elastic member 64 Fluid chamber partition wall 66 Atmospheric pressure chamber S Axial direction

Claims (5)

A vibration isolator for a vehicle engine,
A first attachment member coupled to one of the engine and the vehicle body;
A second mounting member coupled to the other of the engine and the vehicle body;
An elastic body disposed between the first mounting member and the second mounting member and connecting the two;
The elastic body is configured as a part of the partition wall, and a main liquid chamber in which a liquid is enclosed,
A sub liquid chamber in which liquid is enclosed, at least a part of the partition wall is configured by a diaphragm, and can be expanded and contracted according to a change in hydraulic pressure;
A movable wall member that can be displaced by a change in hydraulic pressure as a part of the partition wall, and a partition member that partitions between the main liquid chamber and the sub liquid chamber;
A first restriction passage configured in the partition member to communicate the main liquid chamber and the sub liquid chamber;
An intermediate chamber member that is disposed apart from the movable wall member and forms an intermediate liquid chamber between the movable wall member;
A second restriction passage for communicating the intermediate liquid chamber and the main liquid chamber, or the intermediate liquid chamber and the sub liquid chamber;
A fluid chamber configured adjacent to the intermediate liquid chamber and enclosing a fluid;
An intermediate movable film that partitions between the intermediate liquid chamber and the fluid chamber;
A fluid chamber partition wall that constitutes a part of the partition wall of the fluid chamber and is movably installed in accordance with a change in internal pressure of the fluid chamber; and a support elastic member that elastically supports the fluid chamber partition wall, A fluid chamber switching member whose resonance frequency is set to a frequency higher than the resonance frequency of the second restriction passage in a state in which the fluid chamber partition wall is moved according to the internal pressure of the fluid chamber;
Anti-vibration device with   The vibration isolator according to claim 1, wherein the support elastic member includes a spring member.   The vibration isolator according to claim 1 or 2, wherein air is sealed in the fluid chamber.   The vibration isolator according to any one of claims 1 to 3, wherein an opposite side of the fluid chamber partition to the fluid chamber is open to an atmospheric pressure.   The first restriction passage corresponds to vibrations in a frequency band of 5 Hz to 15 Hz, and the second restriction passage corresponds to vibrations in a frequency band of 40 Hz to 60 Hz when the fluid chamber is expanded or contracted according to fluid pressure. It is comprised so that it may carry out, The vibration isolator of any one of Claims 1-4 characterized by the above-mentioned.

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