JP2007071314A - Vibration isolator - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To maintain a block condition of a liquid pressure opening path making liquid in a pressurized space flow out into a sub liquid chamber when a plunger member moves to an open position side while securing sufficient liquid tightness if the plunger member is on the open position. <P>SOLUTION: In a vibration isolator 10, a blocking surface 119 of a valve element 102 is pressed against a circumference edge part of a bearing hole 84 on an upper end surface of the plunger member 78 and blocks a liquid pressure open path 126 when the plunger member 78 moves from a block position to the open position. Consequently, even if liquid pressure in the main liquid chamber 42 changes and liquid under a pressurized condition flows into the pressurized space 130 from the main liquid chamber 42 through the check valve at a time of idling vibration input, liquid in the pressurized space is surely prevented from flowing out into the sub liquid chamber 44 through the liquid pressure open path 126 since the liquid pressure open path 126 establishing communication between the pressurized space 130 and the sub liquid chamber 44 is blocked by the blocking surface 119. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a fluid-filled vibration isolator that prevents transmission of vibration from a member that generates vibration, and more particularly, to a vibration isolator that is suitably used for an engine mount of an automobile.

  For example, in a vehicle such as a passenger car, a vibration isolator as an engine mount is disposed between an engine serving as a vibration generating unit and a vehicle body serving as a vibration receiving unit, and the vibration isolating device generates vibration generated from the engine. It is structured to absorb and prevent transmission to the vehicle body side. This type of vibration isolator is provided with a main liquid chamber and a sub liquid chamber, and a plurality of orifices communicating with each of these liquid chambers in order to cope with vibrations in a wide range of frequencies. Among the plurality of orifices, one that selectively opens and closes the plurality of orifices by a valve mechanism driven by an electromagnetic solenoid or the like so that the main liquid chamber and the sub liquid chamber communicate with each other by one orifice is known. ing.

  In other words, this vibration isolator requires not only an electric electromagnetic solenoid for controlling the opening / closing state of the orifice and switching the liquid passage between the plurality of orifices, but also the electromagnetic solenoid etc. A controller that operates based on the frequency or the like and switches the orifice is structurally necessary. However, these electromagnetic solenoids and controllers are relatively expensive, and these components significantly complicate the structure of the vibration isolator and make the installation work on the vehicle complicated. It was.

  In view of the above problems, the inventors of the present application disclosed in Patent Document 1 that the main liquid chamber and the sub liquid chamber are communicated with each other by a shake orifice and an idle orifice, and form a part of the idle orifice. The plunger member arranged in the cylinder space communicating with the sub liquid chamber moves to the closed position where the idle orifice is closed by the hydraulic pressure of the main liquid chamber when the shake vibration is input, and the plunger member is moved to the coil spring when the idle vibration is input. An anti-vibration device is disclosed in which the idle orifice is moved to an open position where the idle orifice is opened.

  That is, in the vibration isolator of Patent Document 1, a partition member that divides the space in the outer cylinder into a main liquid chamber and a sub liquid chamber is provided, and a plunger is provided in a cylinder chamber formed on the inner peripheral side of the partition member. The members are arranged so as to be movable in the axial direction, and when a vibration is input, a large fluid pressure change occurs in the main fluid chamber. The fluid flows into the space (hydraulic pressure space) on the liquid chamber side, and the fluid pressure in the fluid pressure space is increased until it is balanced with the fluid pressure (maximum pressure) when the fluid pressure is increased in the main fluid chamber.

At this time, if a shake vibration having a relatively low frequency and a large amplitude is input, the plunger member resists the biasing force of the coil spring by the relatively high hydraulic pressure in the hydraulic pressure space, and the closed position. And is held in this closed position. In addition, when idle vibration having a relatively high frequency and a small amplitude is input, the hydraulic pressure in the hydraulic pressure space is relatively low. Therefore, when the plunger member is in the open position, the coil spring is attached. It is held in the open position by the urging force, and when it is in the closed position, it returns to the open position by the urging force of the coil spring. At this time, if the hydraulic pressure in the hydraulic pressure space increases, the hydraulic pressure prevents the plunger member from moving to the open position. A projecting shaft portion is provided and a through hole penetrating the central portion of the shaft portion is formed, and when the plunger member moves to the open position side, the liquid in the hydraulic space is allowed to pass through the through hole. Also disclosed is a technique for increasing the hydraulic pressure in the hydraulic space by flowing out into the hydraulic pressure space (see FIGS. 13 and 15 of Patent Document 1).
International Publication WO 2004/081408

  However, in the vibration isolator as in Patent Document 1, even when the plunger member moves to the open position and the orifice opening is opened (idle mode), the hydraulic pressure release path is not completely closed ( FIG. 15 of Patent Document 1), when an idle vibration is input, the liquid flows from the main liquid chamber into the hydraulic pressure space through the check valve, and the liquid flows into the auxiliary liquid chamber through the hydraulic pressure release path. As a result, when the idle vibration is input, a phenomenon occurs in which the liquid in the main liquid chamber leaks into the sub liquid chamber through the hydraulic pressure space and the hydraulic pressure release path, so that the flow rate of the liquid in the idle orifice decreases. Since the strength of the resonance phenomenon (liquid column resonance) that occurs in the liquid flowing through the idle orifice is reduced, the damping against idle vibration is also reduced.

  Further, in the vibration isolator as in Patent Document 1, the plunger member is held at the open position by the biasing force of the coil spring when the idle vibration is input. When the pressure changes, the check valve is opened when the hydraulic pressure in the main fluid chamber rises, and the hydraulic pressure in the hydraulic pressure space also changes periodically. For this reason, even if the plunger member that receives the hydraulic pressure in the hydraulic pressure space is held at the open position, vibration along the opening / closing direction occurs. This makes it difficult to maintain the hydraulic pressure release path formed in the plunger member held in the open position in a closed state while ensuring sufficient liquid tightness.

  The object of the present invention is to take into account the above fact, and when the plunger member moves to the open position side, when the plunger member moves to the open position side, a hydraulic pressure release path for allowing the liquid in the hydraulic pressure space to flow into the secondary liquid chamber is provided. In some cases, an object of the present invention is to provide a vibration isolator capable of maintaining a closed state while ensuring sufficient liquid tightness.

  In order to achieve the above object, a vibration isolator according to claim 1 of the present invention includes a first attachment member connected to one of the vibration generating portion and the vibration receiving portion, and the other of the vibration generating portion and the vibration receiving portion. A second mounting member coupled to the first mounting member, an elastic body disposed between the first mounting member and the second mounting member, and a liquid sealed with the elastic body as a part of a partition, A main liquid chamber whose internal volume changes with elastic deformation of the elastic body, a secondary liquid chamber in which liquid is enclosed and whose internal volume can be expanded and contracted, and a main liquid chamber and a secondary liquid chamber that communicate with each other. The first restriction passage, the main liquid chamber and the sub liquid chamber communicate with each other, the second restriction passage having a smaller flow resistance of the liquid than the first restriction passage, the main liquid chamber and the sub liquid. A part of the second restriction passage between the cylinder chamber provided between the chamber and the liquid chamber and the cylinder chamber The orifice space is configured to be divided into an orifice space that communicates with the sub liquid chamber and a hydraulic pressure space that is isolated from the second restriction passage, and a predetermined opening position is provided along the expansion and contraction directions of the orifice space and the hydraulic pressure space. A plunger member movable between a closed position, an orifice opening provided to face the orifice space, and communicating the orifice space with another portion in the second restriction passage; A plunger member is disposed between the main fluid chamber and the fluid pressure space, and a biasing member that biases the plunger member toward the open position for reducing the fluid pressure space, and changes in fluid pressure in the main fluid chamber. A check valve capable of allowing liquid to flow out only in one direction between the main fluid chamber and the hydraulic pressure space, communicating the hydraulic pressure space to the auxiliary fluid chamber, and the plunger member is connected to the biasing member. The open position by urging force When moving to the hydraulic pressure release path for flowing the liquid in the hydraulic pressure space into the sub liquid chamber while restricting the flow rate of the liquid flowing through the inside, and when the plunger member moves to the open position Leakage prevention means for closing the hydraulic pressure release path and opening the hydraulic pressure release path when the plunger member leaves the open position, and the plunger member is urged by the biasing force of the biasing member. When moved to the open position, the orifice opening is opened, and when moved to the closed position against the urging force of the urging member by the hydraulic pressure in the hydraulic pressure space, the orifice opening is closed. And

  The operation of the vibration isolator according to claim 1 of the present invention will be described below.

  In the vibration isolator of claim 1, basically, when vibration is transmitted to one of the first and second mounting members, the elastic body arranged between the first and second mounting members is elastic. The vibration is absorbed by the vibration absorbing action based on the internal friction or the like of the elastic body, and the vibration transmitted to the vibration receiving portion side is reduced.

  In the vibration isolator according to the first aspect, the main liquid chamber and the sub liquid chamber communicate with each other through the first restriction passage, and the main liquid chamber and the sub liquid chamber are in the first state when the orifice opening is open. The two restriction passages having a liquid flow resistance smaller than that of the first restriction passage communicate with each other. Furthermore, in the vibration isolator according to claim 1, when the plunger member located at the open position moves to the closed position by the hydraulic pressure supplied from the main fluid chamber into the hydraulic pressure space through the check valve, the elasticity of the elastic body is increased. With the deformation, the liquid moves back and forth between the main liquid chamber and the sub liquid chamber only through the first restriction passage, and the plunger member in the closed position is moved to the open position by the biasing force of the biasing member. Upon return, both the first restriction passage and the second restriction passage are opened, but the second restriction passage having a relatively small liquid flow resistance is given priority with the elastic deformation of the elastic body. The liquid flows back and forth between the main liquid chamber and the sub liquid chamber.

  That is, in the vibration isolator according to claim 1, when vibration with relatively low frequency and large amplitude (hereinafter referred to as “low frequency vibration”) is input, the elastic body is caused by the low frequency vibration. Due to elastic deformation, a relatively large fluid pressure change occurs in the main fluid chamber, and when the fluid pressure periodically changes in the main fluid chamber, the liquid flows from the main fluid chamber into the fluid pressure space through the check valve, or the fluid pressure The liquid flows out of the space into the main liquid chamber, and the liquid pressure in the hydraulic pressure space reaches an equilibrium pressure that is substantially balanced with the liquid pressure (maximum value or minimum value) in the main liquid chamber. Therefore, if the urging force of the urging member is set smaller than the value corresponding to the equilibrium pressure in the hydraulic pressure space, the plunger member intermittently moves from the open position to the closed position side against the urging force of the urging member. It is moved to the closed position by the hydraulic pressure in the hydraulic pressure space.

  At this time, if the flow resistance of the liquid in the first restriction passage is set (tuned) so as to correspond to the frequency and amplitude of the low-frequency vibration, the main liquid chamber and the auxiliary liquid pass through the first restriction passage. Since a resonance phenomenon (liquid column resonance) occurs in the liquid flowing back and forth between the chambers, low-frequency vibrations can be particularly effectively absorbed by the action of the liquid column resonance.

  In the vibration isolator according to claim 1, when vibration with relatively high frequency and small amplitude (hereinafter referred to as “high frequency range vibration”) is input, the elastic body is elastically deformed by the high frequency range vibration. At the same time, since a relatively small change in hydraulic pressure occurs in the main liquid chamber, in this case as well, liquid flows from the main liquid chamber into the hydraulic pressure space through the check valve when the hydraulic pressure changes periodically in the main liquid chamber. Alternatively, the liquid flows out from the hydraulic pressure space to the main liquid chamber, and reaches an equilibrium pressure at which the hydraulic pressure in the hydraulic pressure space substantially equilibrates with the hydraulic pressure (maximum value or minimum value) in the main liquid chamber. At this time, if the urging force of the urging member is set larger than the value corresponding to the equilibrium pressure in the hydraulic pressure space, the urging force of the urging member holds the plunger member in the open position when the plunger member is in the open position. In the closed position, the urging force of the urging member moves (returns) from the closed position to the open position.

  Therefore, in the vibration isolator according to the first aspect, when the high frequency vibration is input, the second restricting passage having a smaller liquid flow resistance than the first restricting passage is given priority with the elastic deformation of the elastic body. Since the liquid goes back and forth between the main liquid chamber and the sub liquid chamber, the flow resistance of the liquid in the second restriction passage is set (tuned) so as to correspond to the frequency and amplitude of the high frequency vibration. If this is the case, a resonance phenomenon (liquid column resonance) occurs in the liquid that passes between the main liquid chamber and the sub liquid chamber through the second restriction passage. Can be absorbed.

  As a result, according to the vibration isolator according to claim 1, it is possible to respond to a change in the frequency of the input vibration without using a valve mechanism that operates in response to external control and power supply such as an electromagnetic solenoid or a pneumatic solenoid. The restriction passage communicating the main liquid chamber and the sub liquid chamber can be switched to either one of the first restriction passage and the second restriction passage using the change in the liquid pressure in the main liquid chamber as a driving force.

  Further, in the vibration isolator according to claim 1, when the plunger member is disengaged to the open position, the leak preventing means opens the hydraulic pressure release path, so that the input vibration changes from the low frequency vibration to the high frequency vibration, and the plunger When the member starts to move from the closed position to the open position side by the biasing force of the biasing member, the hydraulic pressure release path is opened by the leak prevention means, so the hydraulic pressure space that receives the compressive force from the plunger member The liquid in the fluid flows out into the secondary fluid chamber through the fluid pressure release passage, the increase in fluid pressure in the fluid pressure space is suppressed, and the fluid pressure in the fluid pressure space that acts as a movement resistance on the plunger member can be kept low. As a result, the plunger member can be smoothly moved from the closed position to the open position by the biasing force of the biasing member.

  Further, in the vibration isolator according to claim 1, when the plunger member moves from the closed position side to the open position, the leak preventing means closes the hydraulic pressure release path that connects the hydraulic pressure space to the auxiliary liquid chamber, thereby The fluid pressure in the main fluid chamber changes at the time of input of the region vibration, and the fluid pressure space communicates with the sub fluid chamber even when pressurized liquid flows from the main fluid chamber into the fluid pressure space through the check valve. Since the hydraulic pressure release path to be closed is blocked by the leak prevention means, it is possible to reliably prevent the liquid in the hydraulic pressure space from flowing out into the auxiliary liquid chamber through the hydraulic pressure release path. As a result, the phenomenon that the liquid in the main liquid chamber leaks into the sub liquid chamber through the hydraulic pressure space and the hydraulic pressure release path when the high frequency vibration is input does not occur. Can be prevented, and the attenuation of high-frequency vibrations obtained by the viscous resistance of the liquid flowing through the second restriction passage can be prevented from decreasing.

  A vibration isolator according to claim 2 of the present invention is the vibration isolator according to claim 1, wherein the vibration isolator extends in the cylinder chamber along the expansion / contraction direction and penetrates the plunger member along the expansion / contraction direction. A guide shaft that is slidably inserted into a bearing hole provided so as to be provided is provided, and the hydraulic pressure release path is formed to penetrate the guide shaft along the expansion / contraction direction, thereby preventing the leak The means includes a closing member that, when the plunger member moves to the open position, presses against a peripheral edge of the opening end of the bearing hole on one end face of the plunger member and closes the hydraulic pressure release path together with the bearing hole. It is characterized by.

  A vibration isolator according to claim 3 of the present invention is the vibration isolator according to claim 1, wherein the hydraulic pressure release path faces one end surface of the plunger member facing the hydraulic pressure space and the orifice space. The leak preventing means is formed so as to penetrate between the other end face facing inward, and when the plunger member moves to the open position, the opening end of the hydraulic pressure release path at one end face of the plunger member It has a blocking member that presses the peripheral edge to close the hydraulic pressure release path.

  The vibration isolator according to claim 4 of the present invention is the vibration isolator according to claim 2 or 3, wherein the closing member is made of an elastic material.

  The vibration isolator according to claim 5 of the present invention is the vibration isolator according to claim 4, wherein the check valve is provided in a partition wall partitioning the main liquid chamber and the hydraulic space, A valve seat opening for communicating the main fluid chamber with the hydraulic pressure space, and a pressure contact with a peripheral portion of the valve seat opening with a predetermined pressure, the valve seat opening is changed in accordance with a change in the fluid pressure in the main fluid chamber. And a valve body made of an elastic material that contacts and separates from the peripheral edge, and the closing member is formed integrally with the valve body.

  A vibration isolator according to a sixth aspect of the present invention is the vibration isolator according to any one of the first to fifth aspects, wherein the closing member is connected to the hydraulic space along the expansion / contraction direction in the cylinder chamber. It arrange | positions to the inner wall part which formed one end surface of the side.

  As described above, according to the vibration isolator of the present invention, the plunger member is provided with the hydraulic pressure release path for allowing the liquid in the hydraulic pressure space to flow into the auxiliary liquid chamber when the plunger member moves to the open position side. Can be maintained in a closed state while ensuring sufficient liquid-tightness.

  Hereinafter, a vibration isolator according to an embodiment of the present invention will be described with reference to the drawings. In the figure, symbol S represents the axial center of the apparatus, and the following description will be made with the direction along the axial center S as the axial direction of the apparatus.

(First embodiment)
1 and 2 show a vibration isolator according to a first embodiment of the present invention. As shown in FIG. 1, the vibration isolator 10 is provided with an outer cylinder fitting 12 formed in a thin cylinder on the outer peripheral side thereof, and a mounting bracket 20 is substantially coaxial on the inner circumference side of the outer cylinder fitting 12. Are arranged. An annular flange portion 14 is formed at the upper end portion of the outer cylinder fitting 12 so as to bend toward the outer peripheral side, and a caulking portion 16 is formed at the lower end portion that is bent in a tapered shape toward the inner peripheral side when the apparatus is assembled. Has been. The outer cylindrical member 12 is formed with a narrowed portion 18 that is bent in a U-shaped cross section toward the inner peripheral side on the lower side of the flange portion 14 over the entire circumference. An annular upper step 18A and lower step 18B are provided at the upper end and the lower end, respectively. The outer cylinder member 12 is formed with a circular opening 18C penetrating in the radial direction below the lower stepped portion 18B. The vibration isolator 10 is connected to the vehicle body side of the vehicle via the holder fitting when the outer cylinder fitting 12 is inserted into a cup-shaped holder fitting (not shown).

  The mounting bracket 20 is formed with a cylindrical portion 21 having a substantially constant outer diameter on the upper end side thereof, and a flange-like extending portion 22 extending from the lower end portion of the cylindrical portion 21 to the outer peripheral side. A reduced diameter portion 23 whose outer diameter is reduced in a tapered manner downward is formed below the protruding portion 22. The mounting bracket 20 has a screw hole 20A along the axis S from the upper end surface toward the lower end side. The vibration isolator 10 is connected and fixed to the engine side of the vehicle via a fastening member such as a bolt screwed into the screw hole 20A of the mounting bracket 20 and a bracket stay.

  In the vibration isolator 10, a rubber elastic body 24 formed in a substantially thick ring shape is disposed between the outer cylinder fitting 12 and the attachment fitting 20. The rubber elastic body 24 is vulcanized and bonded to the upper surface of the upper stepped portion 18 </ b> A on the inner peripheral surface of the outer cylindrical fitting 12, and the inner peripheral surface is added to the outer peripheral surface of the reduced diameter portion 23 of the mounting bracket 20. Sulfur bonded. Thereby, the rubber elastic body 24 elastically connects the outer cylinder fitting 12 and the mounting fitting 20.

  The rubber elastic body 24 is formed in a substantially C shape whose cross section is inclined downward from the mounting bracket 20 toward the outer cylindrical bracket 12. As a result, a substantially frustoconical concave portion 26 whose inner diameter becomes narrower from the lower side to the upper side is formed in the central portion of the lower surface of the rubber elastic body 24. The rubber elastic body 24 is integrally formed with a stopper section 28 having a rectangular cross section extending upward from the outer periphery of the upper end thereof. The stopper section 28 is formed on the upper surface side of the extending section 22 of the mounting bracket 20. Is vulcanized and bonded. The stopper portion 28 abuts against a bracket stay or the like to limit the displacement on the engine side when a large relative displacement occurs on the engine side along the axial direction with the vibration isolator 10 attached to the vehicle. Prevents collision noise.

  The rubber elastic body 24 is integrally formed with a cushion portion 30 that covers the lower end portion of the mounting bracket 20 at the inner peripheral portion of the lower end, and a thin cylindrical covering portion 34 that extends downward from the outer peripheral portion of the lower end. Are integrally formed. The covering portion 34 is vulcanized and bonded to the outer cylinder fitting 12 so as to cover the lower side of the upper step portion 18A of the outer cylinder fitting 12. Further, a thick disk-like membrane 32 is integrally formed on the covering portion 34 at a portion facing the opening 18C of the outer cylinder member 12, and the membrane 32 is formed in the opening 18C from the inner peripheral side. The peripheral edge portion is vulcanized and bonded to the outer cylinder member 12. Thereby, the opening 18C is closed by the membrane 32 which is a film-like member having elasticity.

  A partition fitting 36 (see FIG. 3) formed in a substantially thick disk shape as a whole is fitted into the vibration isolator 10 on the inner peripheral side of the outer cylinder fitting 12. The partition metal 36 abuts the outer periphery of the upper surface thereof on the lower surface side of the lower stepped portion 18B, and presses the outer peripheral surface against the inner peripheral surface of the outer cylindrical metal member 12 via the covering portion 34. In addition, an annular support cylinder 38 is fitted into the vibration isolator 10 below the partition fitting 36 on the inner peripheral side of the outer cylinder fitting 12. The upper end side of the support cylinder 38 is brought into contact with the outer peripheral portion of the lower surface of the partition fitting 36, and the outer peripheral surface is pressed against the inner peripheral surface of the outer cylinder fitting 12 through the covering portion 34. In the vibration isolator 10, the inner and outer diameters of the caulking portion 16 of the outer cylinder fitting 12 are reduced from the upper end side toward the lower end side in a state where the partition fitting 36 and the support cylinder 38 are fitted in the outer cylinder fitting 12. It is bent as follows. As a result, the partition fitting 36 and the support cylinder 38 are fixed between the stepped portion 32 (the throttle portion 18) and the caulking portion 16 in the outer cylinder fitting 12.

  The support cylinder 38 is provided with a diaphragm 40 formed into a thin disk shape with a rubber material on the inner peripheral side thereof. The outer peripheral edge of the diaphragm 40 extends over the entire circumference of the support cylinder 38. It is vulcanized and bonded to the peripheral surface. As a result, a substantially cylindrical space (liquid chamber space) in which the upper end side along the axial direction is closed by the rubber elastic body 24 and the lower end side is closed by the diaphragm 40 is formed in the outer cylinder fitting 12. The liquid chamber space is partitioned by the partition metal 36 into a main liquid chamber 42 having the rubber elastic body 24 as a part of the partition wall and a sub liquid chamber 44 having the diaphragm 40 as the partition wall. The main liquid chamber 42 and the sub liquid chamber 44 are filled with a liquid such as water and ethylene glycol, respectively.

  Here, the inner volume of the main liquid chamber 42 changes (expands / contracts) with the elastic deformation of the rubber elastic body 24, and the diaphragm 40 has a sufficiently small load in the direction of expanding / contracting the inner volume of the sub liquid chamber 44. It can be deformed by (hydraulic pressure).

  As shown in FIG. 5, the partition member 36 is provided with an orifice member 46 formed of a metal material such as resin or aluminum on the outer peripheral side thereof, and a thin disk-like lid member on the orifice member 46. 48 is arranged. The orifice member 46 is formed in a thick bottomed cylindrical shape whose bottom surface is closed by the bottom plate portion 50, and the dimension along the circumferential direction of the bottom plate portion 50 extends from the inner peripheral side to the outer peripheral side. A plurality of (for example, four) circulation openings 52 formed in a substantially fan shape are formed, and a thick cylindrical boss portion 54 is formed on the inner peripheral side of the circulation opening 52 as shown in FIG. It is integrally formed.

  As shown in FIG. 3, the dimension along the axial direction of the boss portion 54 is larger than the thickness of the bottom plate portion 50, and the outer peripheral surface protrudes in a step shape from the upper surface side of the bottom plate portion 50. . A circular concave seat receiving hole 56 is opened in the center of the upper surface of the boss portion 54, and a lower end portion of a coil spring 90 described later is inserted into the seat receiving hole 56. In addition, the orifice member 46 is integrally formed with a round rod-shaped guide rod 57 projecting along the axis S from the center of the bottom surface of the seat receiving hole 56, and the shaft center on the inner peripheral side of the guide rod 57. A hydraulic pressure release passage 126 that passes between the upper end surface of the guide rod 57 and the bottom surface of the orifice member 46 is formed along S.

  As shown in FIG. 5, the orifice member 46 is formed with a shake groove 60 and a shake groove 62 extending in the circumferential direction on the upper end side and the lower end side of the outer peripheral surface thereof. An idle groove 64 is formed between 60 and 62 so as to extend in the circumferential direction. Here, the shake groove 60 and the idle groove 64 are formed in a substantially C shape in which one end portion along the circumferential direction is closed and the other end portion is opened in a plan view. 46 both ends of the circumferential direction which circulates the outer peripheral surface of 46 substantially over one round are formed in the C shape where each was obstruct | occluded. The shake grooves 60 and 62 have substantially the same width along the axial direction and the cross-sectional areas are substantially equal to each other, but the idle groove 64 has a width along the axial direction wider than that of the shake grooves 60 and 62. The cross-sectional area is larger than the cross-sectional area of the shake grooves 60 and 62.

  A concave communication groove 66 is formed in the orifice member 46 so as to extend in the axial direction on the outer peripheral surface thereof, and the upper end portion of the communication groove 66 opens to the outer peripheral portion of the upper surface of the orifice member 46. The lower end side is closed by a partition plate 72 that partitions the shake groove 62 and the idle groove 64 along the axial direction. Further, the end portions on the opening side of the shake groove 60 and the idle groove 64 are respectively connected to the side end portions on one side along the circumferential direction of the communication groove 66. As shown in FIG. 1, a concave intermediate groove 68 extending in the axial direction is formed on the outer peripheral surface of the orifice member 46, and the intermediate groove 68 is closed at the upper end portion of the shake groove 60. The lower end portion is connected to the vicinity of one end portion of the shake groove 62, and the shake groove 60 and the shake groove 62 are communicated with each other. The orifice member 46 is formed with a communication hole 66 penetrating between the vicinity of the other end of the shake groove 62 and the lower surface of the orifice member 46 on the outer peripheral side of the lower end portion.

  As shown in FIG. 3, the orifice member 46 has an orifice opening 74 penetrating between the inner peripheral surface of the idle groove 64 and the inner peripheral surface of the orifice member 46. The orifice opening 74 is disposed at a portion near the closed end of the idle groove 64 and is formed in a slot shape elongated in the circumferential direction as shown in FIG. Here, the opening area of the orifice opening 74 is larger than the cross-sectional area of the idle groove 64. In addition, the orifice opening 74 has a substantially semicircular shape at both ends along the inner peripheral end thereof, and an increase in the flow resistance of the liquid in the vicinity of both ends is suppressed. Further, the cross-sectional shape along the liquid flow direction at the inner peripheral edge portion (edge portion) of the orifice opening 74 may be a convex semicircular shape or wedge shape so as to suppress an increase in liquid flow resistance at the edge portion.

  As shown in FIG. 5, a cylindrical space is formed on the inner peripheral side of the orifice member 46, and this cylindrical space serves as a cylinder chamber 76 in which a plunger member 78 described later is accommodated. The plunger member 78 is formed in a thick disk shape, and the hydraulic chamber 130 (see FIG. 4), which is a small space on the main liquid chamber 42 side along the axial direction of the cylinder chamber 76, and the sub liquid chamber 44 side. It is divided into an orifice space 132 (see FIG. 3) which is a small space. The plunger member 78 has an edge portion 79 on the lower end side of the outer peripheral surface thereof extending in parallel with the longitudinal direction of the orifice opening 74.

  As shown in FIG. 3, the plunger member 78 is formed with an annular groove portion 80 extending in the circumferential direction on the inner peripheral side of the lower end surface thereof, and a thick cylindrical shape is formed on the inner peripheral side of the annular groove portion 80. The seat receiving portion 86 is integrally formed. The plunger member 78 is provided with a bearing hole 84 penetrating along the axis S from the upper end surface to the lower end surface of the seat receiving portion 86. The plunger member 78 has an annular recess 82 formed on the outer peripheral side of the bearing hole 84 on the upper end surface thereof, and this annular recess 82 is provided on the lower surface of the holder member 100 even when the plunger member 78 is in an open position described later. A space of a constant volume (hydraulic pressure space 130) is formed between the two.

  As shown in FIG. 3, the plunger member 78 is inserted into the cylinder chamber 76 of the orifice member 46, and the guide rod 57 of the orifice member 46 slides relatively along the axial direction in the bearing hole 84. Inserted as possible. Accordingly, the plunger member 78 is movable (slidable) in the axial direction along the inner peripheral surface of the cylinder chamber 76 and the outer peripheral surface of the guide rod 57.

  Here, when one of the plunger member 78 and the guide rod 57 in which the bearing hole 84 is formed is made of metal, the other is made of a material whose Young's modulus such as resin is different by a predetermined value or more and whose frictional resistance is small. It is preferable to form. In addition, one or both of the inner peripheral surface of the bearing hole 84 and the outer peripheral surface of the guide rod 57 may be coated with a material having lubricity and high wear resistance to suppress frictional resistance during sliding. .

  A coil spring 90 as an urging member is disposed on the partition metal 36 between the bottom plate portion 50 of the orifice member 46 and the lower end portion of the plunger member 78. The upper end of the coil spring 90 is fitted on the outer peripheral side of the seat receiving portion 86 of the plunger member 78, and the lower end is inserted into the seat receiving hole 56 of the orifice member 46. In this state, the coil spring 90 has its upper end surface (upper seat surface) pressed against the peripheral edge portion of the seat receiving portion 86 of the plunger member 78 and its lower end surface (lower seat surface) is the bottom surface portion of the seat receiving hole 56. The plunger member 78 and the bottom plate portion 50 are always held in a compressed state. Thereby, the coil spring 90 always biases the plunger member 78 upward (to the main liquid chamber 42 side).

  As shown in FIG. 3, in the partition member 36, the lid member 48 is in contact with the upper end surface of the orifice member 46, and in this state, for example, a caulking protrusion (not shown) protruding from the upper end surface of the orifice member 46. Is inserted into a caulking hole formed in the lid member 48 and the front end side of the caulking projection is crushed, whereby the lid member 48 is caulked and fixed on the orifice member 46. By fixing the lid member 48 to the orifice member 46, the upper end side of the cylinder chamber 76 of the orifice member 46 is closed by the lid member 48. As shown in FIG. 5, the lid member 48 has a circular insertion hole 94 formed in the center thereof, and a plurality of fan-shaped holes (in the present embodiment) formed on the outer peripheral side of the insertion insertion hole 94. Then, four valve seat openings 96 are formed. These valve seat openings 96 are arranged so as to have a symmetrical positional relationship (point symmetry) about the axis S. Further, as shown in FIG. 5, the lid member 48 has a notch 98 formed on the outer periphery thereof so as to face the upper end side of the communication groove 66 of the orifice member 46. Thus, the shake groove 60 and the idle groove 64 communicate with the sub liquid chamber 44 via the communication groove 66 and the notch 98, respectively.

  As shown in FIG. The partition member 36 is provided with a substantially disc-shaped holder member 100 between the lid member 48 and the plunger member 78, and a substantially disc-shaped valve body between the holder member 100 and the lid member 48. 102 is interposed. As shown in FIG. 3, the holder member 100 is formed with a valve body holder 104 having a bottomed cylindrical shape having a shallow bottom at the center thereof, and from the upper end portion of the valve body holder 104 to the outer peripheral side. An extending annular flange portion 106 is bent. A notch 107 is formed in the flange 106 so as to face the notch 98 of the lid member 48. The holder member 100 is formed with a plurality of communication openings 108 each formed in a fan shape on the outer periphery of the bottom plate portion 105 of the valve body holder 104. A circular insertion hole 112 is formed at the center of the bottom plate portion 105. Here, a valve body storage chamber 114 is formed between the lid member 48 and the bottom plate portion 105 of the holder member 100, which is a disc-shaped space whose thickness along the axial direction is substantially constant. The valve body 102 is stored in the body storage chamber 114.

  The valve body 102 is molded from a rubber composition such as NR, NBR, etc., and the upper surface side is formed into a flat shape, and the lower surface side is formed in a slope shape slightly inclined upward from the inner peripheral side to the outer peripheral side. The thickness along the axial direction gradually decreases from the inner peripheral side toward the outer peripheral side. As shown in FIG. 5, the valve body 102 has a circular convex protrusion 116 formed at the center of the upper surface, and a circular convex protrusion 118 formed at the center of the lower surface. Here, the protrusion 118 on the lower surface side has an outer diameter and a height along the axial direction larger than the protrusion 116 on the upper surface side, and the lower end surface of the protrusion 118 is a flat blocking surface 119. The outer diameter of the closing surface 119 is slightly larger than the inner diameter of the bearing hole 84 of the plunger member 78.

  The valve body 102 has a projection 116 on the upper surface side inserted into the insertion insertion hole 94 of the lid member 48, and a projection 118 on the lower surface side inserted into the insertion insertion hole 112 of the holder member 100. Thereby, the valve body 102 is positioned coaxially with the holder member 100 and the lid member 48, and the movement in the radial direction is restricted. At this time, the protrusion 118 inserts the closing surface 119 into the hydraulic space 130 through the bottom plate portion 105 of the holder member 100.

  The valve body 102 is compressed in the axial direction between the lid member 48 and the bottom plate portion 105 of the holder member 100 in the vicinity of the peripheral portions of the protrusions 116 and 118. As a result, the upper surface of the valve body 102 is brought into pressure contact with the lower surface side of the lid member 48 with a predetermined pressure (pre-pressure), and movement in the axial direction between the lid member 48 and the holder member 100 is restricted. Is done. As shown by a two-dot chain line in FIG. 3, the valve body 102 can be deformed by bending the outer peripheral side of the compressed portion downward.

  As shown in FIG. 3, the valve body 102 has its outer peripheral end positioned radially outside the outer peripheral end of the valve seat opening 96 in the lid member 48 along the radial direction, and of the communication opening 108 of the holder member 100. It is located on the inner peripheral side with respect to the outer peripheral end. As a result, the valve body 102 closes the valve seat opening 96 whose upper surface portion is pressed against the lid member 48, and the outer peripheral side is bent and deformed downward as shown by a two-dot chain line in FIG. When separated from the member 48 (open state), the valve seat opening 96 communicates with the communication opening 108 via the valve body storage chamber 114, and the main liquid chamber 42 passes through the valve body storage chamber 114 and enters the partition metal 36. The cylinder chamber 76 communicates with each other. That is, the valve body 102, the lid member 48, and the holder member 100 housed in the valve body housing chamber 114 constitute a check valve 128 between the main liquid chamber 42 and the cylinder chamber 76. The valve 128 allows inflow of liquid only from the main liquid chamber 42 into the cylinder chamber 76 (hydraulic pressure space 130), but prevents outflow of liquid from the hydraulic pressure space 130 into the main liquid chamber 42.

  The orifice space 132 of the cylinder chamber 76 is always in communication with the sub liquid chamber 44 through the plurality of flow openings 52 of the orifice member 46. The hydraulic space 130 of the cylinder chamber 76 communicates with the auxiliary fluid chamber 44 through a hydraulic pressure release passage 126 that penetrates the central portion of the orifice member 46.

  As shown in FIG. 1, in the vibration isolator 10, the outer peripheral sides of the communication groove 66, the shake grooves 60 and 62, and the idle groove 64 in the orifice member 46 are respectively formed by the inner peripheral surface of the outer cylinder fitting 12 through the covering portion 34. Blocked. As a result, elongated spaces are formed along the circumferential direction in the shake grooves 60 and 62 and the idle groove 64, respectively. The communication groove 66, the shake grooves 60 and 62, and the communication hole 66 are formed in the main liquid chamber 42 and the auxiliary liquid. A shake orifice 122 which is a first restriction passage communicating with the chamber 44 is formed. The orifice space 132 communicated with the idle groove 64 through the communication groove 66, the idle groove 64, and the orifice opening 74 has an idle orifice 124 as a second restriction passage for communicating the main liquid chamber 42 and the sub liquid chamber 44 with each other. Form.

  Here, the shake orifice 122 has a path length and a cross-sectional area, that is, a liquid flow resistance so as to correspond to a shake vibration (for example, 9 to 15 Hz) which is a vibration in a relatively low frequency region of the input vibration. Is set (tuned). In addition, the flow resistance of the liquid in the idle orifice 124 is smaller than the flow resistance of the liquid in the shake orifice 122, and this flow resistance (cross-sectional area and path length) is a relatively low frequency vibration of the input vibration. Is set (tuned) so as to correspond to idle vibration (for example, 18 to 30 Hz).

  In the vibration isolator 10, as shown in FIG. 4, when the plunger member 78 moves (lowers) to the closed position, the orifice opening 74 of the orifice member 46 is closed by the outer peripheral surface of the plunger member 78, and the idle groove 64 is formed in the orifice. The communication with the space 132 is not established. As a result, the main liquid chamber 42 and the sub liquid chamber 44 communicate with each other only through the shake orifice 122.

  At this time, the lower end side region on the outer peripheral surface of the plunger member 78 is positioned (overlapped) along the axial direction on the inner peripheral side of the region below the orifice opening 74 on the inner peripheral surface of the cylinder chamber 76. At this time, the overlap amount OL (see FIG. 4) with the plunger member 78 and the inner peripheral surface of the cylinder chamber 76 is set to about 2.5 to 3.0 mm, for example. In this state, the plunger member 78 and the inner peripheral surface of the cylinder chamber 76 are overlapped in the state where the plunger member 78 is in the closed position. Even if the plunger member 78 vibrates with a small amplitude along the axial direction due to the change, the orifice opening 74 can be reliably maintained in the closed state by the plunger member 78.

  In the vibration isolator 10, as shown in FIG. 3, when the plunger member 78 moves (rises) to the open position, the plunger member 78 moves away from the orifice opening 74, the orifice opening 74 is opened, and the common orifice unit 70 is opened. The orifice space 132 is in communication. As a result, the main liquid chamber 42 and the sub liquid chamber 44 communicate with each other through both the shake orifice 122 and the idle orifice 124. However, when the liquid pressure in the main liquid chamber 42 changes, the main liquid chamber 42 and the sub liquid chamber 44 start from the main liquid chamber 42. The liquid that has flowed into the communication groove 66 preferentially flows into the orifice space 132 through the idle groove 64 where the flow resistance of the liquid is smaller than that of the shake groove 60, and into the idle groove 64 through the orifice opening 74. The liquid that has flown into the main liquid chamber preferentially passes through the communication groove 66 having a liquid flow resistance smaller than that of the idle groove 64 and then flows into the main liquid chamber 42. Thereby, in the vibration isolator 10, when the plunger member 78 is in the open position, the liquid flows between the main liquid chamber 42 and the sub liquid chamber 44 substantially only through the idle orifice 124.

  In the vibration isolator 10, when the plunger member 78 in the closed position moves to the open position side by the urging force of the coil spring 90, the liquid in the hydraulic pressure space 130 closed from the outside through the hydraulic pressure release path 126 is subsidized. The plunger member 78 is moved to the open position side while flowing into the liquid chamber 132. In the vibration isolator 10, as shown in FIG. 3, the closing surface 119 of the valve body 102 is in pressure contact with the peripheral portion of the bearing hole 84 on the upper end surface of the plunger member 78. As a result, the upper opening end of the bearing hole 84 is closed, and the hydraulic pressure release path 126 that opens the upper opening end in the bearing hole 84 is also closed by the closing surface 119.

  At this time, the protrusion 118 of the valve body 102 is locally compressed and deformed in the axial direction by the pressure applied from the plunger member 78 (the urging force of the coil spring 90) at the outer peripheral side in pressure contact with the plunger member 78. At this time, the protrusion 118 has a predetermined rigidity in the axial direction so that the amount of compressive deformation is a predetermined precompression amount PC. The pre-compression amount PC is equal to or less than the protrusion amount of the protrusion 118 from the lower surface side of the bottom plate portion 105.

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

  In the vibration isolator 10, for example, when an engine in a vehicle is operated, vibration generated by the engine is transmitted to the rubber elastic body 24 via the mounting bracket 20, and the rubber elastic body 24 is elastically deformed. At this time, the rubber elastic body 24 acts as a main vibration absorber, and the vibration is absorbed by the vibration absorbing action based on the internal friction or the like of the rubber elastic body 24, so that the vibration transmitted to the vehicle body side via the outer cylinder fitting 12 is reduced. . In vehicles such as automobiles, the engine generates idle vibrations that are relatively high-frequency vibrations during idling, and the engine generates shake vibrations that are relatively low-frequency vibrations when traveling at a predetermined speed or higher. appear.

  In the vibration isolator 10, when the plunger member 78 moves from the open position to the closed position against the urging force of the coil spring 90 by the hydraulic pressure in the hydraulic space 130 of the cylinder chamber 76, the orifice opening 74 is closed, When returning from the closed position to the open position by the biasing force of the coil spring 90, the orifice opening 74 is opened, so that the plunger member 78 in the open position passes from the main liquid chamber 42 into the hydraulic pressure space 130 through the check valve 128. When moved to the closing position by the supplied hydraulic pressure, the liquid moves back and forth between the main liquid chamber 42 and the sub liquid chamber 44 through only the shake orifice 122 with the elastic deformation of the rubber elastic body 24, and is also blocked. When the plunger member 78 at the position returns to the open position by the biasing force of the coil spring 90, the shake orifice 122 and the arm Both of the dollar orifices 124 are opened, but with the elastic deformation of the rubber elastic body, the main liquid chamber 42 and the sub liquid chamber preferentially pass through the idle orifice 124 having a relatively small flow resistance of the liquid. Liquid goes back and forth between 44 and 44.

  That is, in the vibration isolator 10, when a shake vibration having a relatively low frequency and a large amplitude is input, the rubber elastic body 24 is elastically deformed by the shake vibration, and a relatively large liquid is contained in the main liquid chamber 42. As the pressure changes, the liquid flows from the main fluid chamber 42 into the hydraulic pressure space 130 through the check valve 128 when the hydraulic pressure in the main fluid chamber 42 periodically increases, and the hydraulic pressure in the hydraulic pressure space 130 is also main. The pressure in the liquid chamber 42 rises to an equilibrium pressure that is substantially in equilibrium with the rising liquid pressure.

  Here, in the vibration isolator 10, the urging force of the coil spring 90 is set to be smaller than the value corresponding to the hydraulic pressure (equilibrium pressure) in the hydraulic pressure space 130 when the shake vibration is input. When vibration is input, the plunger member 78 moves intermittently from the open position to the closed position against the biasing force of the coil spring, and is held at the closed position by the hydraulic pressure in the hydraulic pressure space 130.

  Therefore, in the vibration isolator 10, when the shake vibration is input, the liquid moves back and forth between the main liquid chamber 42 and the sub liquid chamber 44 only through the shake orifice 122 in accordance with the elastic deformation of the rubber elastic body 24. Since the input vibration (low frequency range vibration) can be absorbed by the viscous resistance and pressure loss of the liquid passing through the shake orifice, the shake vibration transmitted from the engine side to the vehicle body side can be reduced.

  At this time, the flow resistance of the liquid in the shake orifice 122 is set (tuned) so as to correspond to the frequency and amplitude of the shake vibration, so that the main liquid chamber 42 and the sub liquid chamber 44 pass through the shake orifice 122. A resonance phenomenon (liquid column resonance) occurs in the liquid flowing back and forth, and shake vibration can be absorbed particularly effectively by the action of the liquid column resonance.

  In the vibration isolator 10, when idle vibration having a relatively high frequency and a small amplitude is input, the rubber elastic body 24 is elastically deformed by the idle vibration and a relatively small liquid is contained in the main liquid chamber 42. In this case as well, since the pressure changes, the liquid flows from the main fluid chamber 42 into the hydraulic pressure space through the check valve 128 when the hydraulic pressure in the main fluid chamber 42 periodically rises. Of the main liquid chamber 42 reaches an equilibrium pressure that is substantially in equilibrium with the hydraulic pressure (maximum value) at the time of ascent in the main liquid chamber 42.

  However, in the vibration isolator 10, the urging force of the coil spring 90 is set to be larger than the value corresponding to the equilibrium pressure in the hydraulic pressure space 130 at the time of input of idle vibration, whereby the plunger member 78 is opened. When the coil spring 90 is in the closed position, the coil spring 90 is held at the open position. When the coil spring 90 is in the closed position, the coil spring 90 is moved (returned) from the closed position to the open position.

  Therefore, in the vibration isolator 10, when the idle vibration is input, the main liquid chamber 42 preferentially passes through the idle orifice 124 having a small liquid flow resistance with respect to the shake orifice 122 in accordance with the elastic deformation of the rubber elastic body 24. Since the liquid flows back and forth between the gas and the auxiliary liquid chamber 44, the input vibration (idle vibration) can be absorbed by the viscous resistance and pressure loss of the liquid flowing through the idle orifice 124, so that the vibration is transmitted from the engine side to the vehicle body side. Can reduce idle vibration.

  At this time, since the flow resistance of the liquid in the idle orifice 124 is set (tuned) so as to correspond to the frequency and amplitude of the idle vibration, the main liquid chamber 42 and the sub liquid chamber 44 pass through the idle orifice 124. A resonance phenomenon (liquid column resonance) occurs in the liquid flowing back and forth, and idle vibration can be absorbed particularly effectively by the action of the liquid column resonance.

  As a result, according to the vibration isolator 10, the main liquid chamber 42 and the sub liquid chamber 44 are communicated with each other without using a valve mechanism that operates in response to external control and power supply such as an electromagnetic solenoid or a pneumatic solenoid. The orifice to be switched can be switched to either the shake orifice 122 or the idle orifice 124 according to the frequency of the input vibration, using the change in the hydraulic pressure in the main liquid chamber 42 as the driving force.

  Further, in the vibration isolator 10, when the plunger member 78 is removed from the open position, the closing surface 119 of the valve body 102 is separated from the upper end surface of the plunger member 78, and the hydraulic pressure release path 126 is opened, so that input vibration is generated. When the vibration is changed from the shake vibration to the idle vibration and the plunger member 78 starts to move from the closed position to the open position side by the biasing force of the coil spring 90, the closed surface 119 is separated from the plunger member 78, and the hydraulic pressure is released. Since the passage 126 is open, the liquid in the hydraulic pressure space 130 that has received the compressive force from the plunger member 78 flows out into the auxiliary fluid chamber through the hydraulic pressure release passage 126, and the hydraulic pressure in the hydraulic pressure space 130 increases. Is suppressed, and the hydraulic pressure in the hydraulic pressure space 130 acting as a movement resistance on the plunger member 78 can be kept low. As a result, the plunger member 78 can be smoothly moved from the closed position to the open position by the biasing force of the coil spring 90.

  Further, in the vibration isolator 10, when the plunger member 78 moves from the closed position side to the open position, the closed surface 119 of the valve body 102 comes into pressure contact with the peripheral edge portion of the bearing hole 84 on the upper end surface of the plunger member 78 and the hydraulic pressure release path. By closing 126, the fluid pressure in the main fluid chamber 42 changes when an idle vibration is input, and pressurized liquid flows from the main fluid chamber 42 into the fluid pressure space 130 through the check valve 128. In addition, since the hydraulic pressure release passage 126 communicating the hydraulic pressure space 130 and the auxiliary fluid chamber 44 is closed by the closing surface 119, the liquid in the hydraulic pressure space 130 passes through the hydraulic pressure release passage 126 and enters the auxiliary fluid chamber 44. Can be surely prevented from leaking out.

  As a result, a phenomenon in which the liquid in the main liquid chamber 42 leaks into the sub liquid chamber 44 through the hydraulic pressure space 130 and the hydraulic pressure release path 126 does not occur when the idle vibration is input. It is possible to prevent a decrease in the flow rate of the liquid, to prevent a decrease in the strength of the resonance phenomenon (liquid column resonance) that occurs in the liquid flowing through the idle orifice 124, and to reduce the attenuation against the idle vibration obtained by the viscous resistance of the liquid. Can be prevented.

  Further, in the vibration isolator 10, the plunger member 78 is held in the open position by the biasing force of the coil spring 90 when the idle vibration is input. When the change occurs, the check valve is opened when the hydraulic pressure in the main fluid chamber 42 increases, and the hydraulic pressure in the hydraulic pressure space also changes periodically. For this reason, even if the plunger member 78 receiving the hydraulic pressure in the hydraulic pressure space 130 is urged to the open position by the coil spring 90, minute vibrations along the axial direction according to the change in hydraulic pressure are generated.

  In order to correspond to the above point, the vibration isolator 10 causes the protrusion 118 to undergo a compressive deformation of a predetermined precompression amount PC along the axial direction in a state where the closing surface 119 is pressed against the plunger member 78. The precompression amount PC is set to be larger than the amplitude of the plunger member 78 that vibrates when an idle vibration is input. Thus, in the vibration isolator 10, even if the plunger member 78 in the open position vibrates due to a change in the hydraulic pressure in the hydraulic pressure space 130, the closing surface 119 is placed on the peripheral portion of the bearing hole 84 on the upper end surface of the plunger member 78. Since the pressure contact state can be maintained, the fluid pressure release path 126 can be reliably closed by the closing surface 119 when the idle vibration is input.

  Further, in the vibration isolator 10, since the projection 118 is formed of a rubber material integrally with the valve body 102, the number of parts does not increase even if the closing surface 119 is provided, and the plunger 118 Since 78 does not directly collide with the bottom plate portion 105 of the holder member 100, it is possible to prevent the plunger member 78 from colliding with the bottom plate portion 105 and generating a hitting sound.

(Second Embodiment)
FIG. 6 shows a vibration isolator according to the second embodiment of the present invention. In the vibration isolator 140 according to this embodiment, the same parts as those of the vibration isolator 10 according to the first embodiment are denoted by the same reference numerals, and description thereof is omitted.

  The vibration isolator 140 according to the present embodiment is different from the vibration isolator 10 according to the first embodiment in that the hydraulic pressure release path 142 is not the central portion of the plunger member 78 but the bearing hole 84 along the radial direction. It is a point provided between the annular recess 82. The hydraulic pressure release path 142 has an upper open end that opens in a region between the bearing hole 84 on the upper end surface of the plunger member 78 and the inner peripheral end of the annular recess 82, and a lower open end that has the annular groove 80. Opened to the bottom of the. In addition, a disc-shaped closing portion 144 that extends from the lower end portion to the outer peripheral side is integrally formed on the protruding portion 118 of the valve body 102, and the upper surface side of the closing portion 144 is the lower surface of the bottom plate portion 105. It is fixed to the side by adhesion or the like.

  The closing portion 144 has a flat closing surface 146 on the lower surface side. When the plunger member 78 moves to the open position, the closing surface 146 moves to the plunger position as in the closing surface 146 according to the first embodiment. When the hydraulic pressure release path 142 is closed by pressing against the region including the opening end of the hydraulic pressure release path 142 in the member 78, and the plunger member 78 moves from the closed position to the open position side, it is separated from the upper end surface of the plunger member 78. Then, the hydraulic pressure release path 142 is opened. Further, in the closed portion 144, compression deformation of a predetermined precompression amount PC occurs along the axial direction in a state of being in pressure contact with the upper end surface of the plunger member 78. This precompression amount PC can be basically set to the same size as the precompression amount of the protrusion 118 in the vibration isolator 10 according to the first embodiment.

  Next, the operation of the vibration isolator 140 according to the embodiment of the present invention will be described.

  Similarly to the vibration isolator 10 according to the first embodiment, the vibration isolator 140 also uses the main fluid without using a valve mechanism that operates by receiving external control and power supply such as an electromagnetic solenoid or a pneumatic solenoid. The orifice communicating the chamber 42 and the sub liquid chamber 44 is switched to either the shake orifice 122 or the idle orifice 124 using the change in the liquid pressure in the main liquid chamber 42 as a driving force in accordance with the frequency of the input vibration. Therefore, both the shake vibration and the idle vibration input from the engine side can be effectively attenuated and absorbed, and the vibration transmitted to the vehicle body side can be reduced.

  Further, in the vibration isolator 140, when the plunger member 78 is detached from the open position, the closing surface 146 of the closing portion 144 is separated from the upper end surface of the plunger member 78 and the hydraulic pressure release path 126 is opened, so that input vibration is generated. When the vibration is changed from the shake vibration to the idle vibration and the plunger member 78 starts to move from the closed position to the open position side by the biasing force of the coil spring 90, the closed portion 144 is separated from the plunger member 78, and the hydraulic pressure is released. Since the passage 126 is open, the liquid in the hydraulic pressure space 130 that has received the compressive force from the plunger member 78 flows out into the auxiliary fluid chamber through the hydraulic pressure release passage 126, and the hydraulic pressure in the hydraulic pressure space 130 increases. Is suppressed, and the hydraulic pressure in the hydraulic pressure space 130 acting as a movement resistance on the plunger member 78 can be kept low. As a result, the plunger member 78 can be smoothly moved from the closed position to the open position by the biasing force of the coil spring 90.

  Further, in the vibration isolator 140, when the plunger member 78 moves from the closed position side to the open position, the closed surface 146 of the closed portion 144 comes into pressure contact with the upper end surface of the plunger member 78 to close the hydraulic pressure release path 142. Even when the fluid pressure in the main fluid chamber 42 changes when an idle vibration is input and a pressurized liquid flows from the main fluid chamber 42 into the fluid pressure space 130 through the check valve 128, the fluid pressure space 130 Since the hydraulic pressure release path 126 communicating with the auxiliary liquid chamber 44 is closed by the closing surface 146, it is ensured that the liquid in the hydraulic pressure space 130 flows out into the auxiliary liquid chamber 44 through the hydraulic pressure release path 126. Can be prevented. As a result, a phenomenon in which the liquid in the main liquid chamber 42 leaks into the sub liquid chamber 44 through the hydraulic pressure space 130 and the hydraulic pressure release path 126 does not occur when the idle vibration is input. It is possible to prevent a decrease in the flow rate of the liquid, to prevent a decrease in the strength of the resonance phenomenon (liquid column resonance) that occurs in the liquid flowing through the idle orifice 124, and to reduce the attenuation against the idle vibration obtained by the viscous resistance of the liquid. Can be prevented.

  Further, in the vibration isolator 140, even when the plunger member 78 vibrates along the axial direction at the time of input of idle vibration, a compression deformation of a predetermined precompression amount PC is applied to the closed portion 144 that is in pressure contact with the upper end surface of the plunger member 78. As a result, the closed surface 146 can be maintained in pressure contact with the upper end surface of the plunger member 78, so that the hydraulic pressure release path 126 can be reliably closed by the closed surface 146 when an idle vibration is input.

  Further, in the vibration isolator 10, since the closed portion 144 is formed of a rubber material integrally with the valve body 102, the number of parts does not increase even if the closed portion 144 is provided, and the closed portion 144 does not increase the plunger member. Since 78 does not directly collide with the bottom plate portion 105 of the holder member 100, it is possible to prevent the plunger member 78 from colliding with the bottom plate portion 105 and generating a hitting sound.

  In the vibration isolators 10 and 140 according to the present embodiment, the protruding portion 118 formed with the closed surface 119 or the closed portion 144 formed with the closed surface 146 is formed integrally with the valve body 102 by a rubber material. Of course, the protrusion 118 or the closing portion 144 may be configured as a part separated from the valve body 102, and the outer periphery of the bearing hole 84 or the hydraulic pressure release path 142 on the upper end surface of the plunger member 78. When the elastic ring is fixed to the side and the plunger member 78 moves to the open position, the hydraulic pressure release paths 126 and 142 may be closed by pressing the elastic ring against the bottom plate portion 105 of the holder member 100.

  In the vibration isolators 10 and 140, one of the two orifices (first restriction passage and second restriction passage) is a shake orifice 122 corresponding to shake vibration, and the other is an idle orifice 124 corresponding to idle vibration. However, the two first restriction passages and the second restriction passage need not necessarily correspond to the shake vibration and the idle vibration, and the first restriction passage corresponds to the vibration of a relatively low frequency range. The second restriction path only needs to correspond to vibration in a relatively high frequency range. Further, in the vibration isolator 10, the mounting bracket 20 is connected to the engine side and the outer cylinder member 12 is connected to the vehicle body side. On the contrary, the mounting bracket 20 is connected to the vehicle body side. The outer cylinder member 12 may be connected to the engine side.

  Further, in the vibration isolator 10, 140 according to the present embodiment, liquid is supplied from the main fluid chamber 42 into the hydraulic space 130 through the check valve 128 when the hydraulic pressure in the main fluid chamber 42 is increased, and this hydraulic space 130. The fluid pressure in the fluid pressure chamber 130 is increased to an equilibrium pressure corresponding to the fluid pressure upper limit value of the main fluid chamber 42, and when the shake vibration is input, the plunger member 78 is moved from the open position to the closed position by the fluid pressure (positive pressure) in the fluid pressure space 130. Contrary to this, the check valve is configured so that the liquid can flow out only from the hydraulic pressure space 130 to the main fluid chamber 42, and when the hydraulic pressure in the main fluid chamber 42 decreases, By causing the liquid to flow out from the hydraulic pressure space 130 into the main fluid chamber 42 through the check valve, the hydraulic pressure in the hydraulic pressure space 130 is reduced to an equilibrium pressure corresponding to the lower limit value of the hydraulic pressure in the main fluid chamber 42, When vibration is input, the pressure is reduced by the hydraulic pressure (negative pressure) in the hydraulic pressure space 130. The Ja member 78 from the open position may be be moved to the closed position.

  In the above-described case, the vibration isolator 10 or 140 is configured so that the plunger member 78 is urged downward along the axial direction by the coil spring 90 and the orifice member 78 is in the lower limit position (open position). The opening 74 is opened, and the orifice opening 74 is opened when the negative pressure in the hydraulic space 130 rises from the lower limit position to the upper limit position (closed position) against the biasing force of the coil spring 90. Is done.

It is sectional drawing along the axial direction which shows the structure of the vibration isolator which concerns on the 1st Embodiment of this invention, and has shown the state which has a plunger member in an open position. It is sectional drawing along the axial direction which shows the structure of the vibration isolator shown by FIG. 1, and has shown the state which has a plunger main body in the obstruction | occlusion position. It is sectional drawing which shows the structure of the partition metal fitting and plunger member in the vibration isolator shown by FIG. 1, and has shown the state which has a plunger member in an open position. It is sectional drawing which shows the structure of the partition metal fitting and plunger member in the vibration isolator shown by FIG. 1, and has shown the state which has a plunger member in a obstruction | occlusion position. It is a disassembled perspective view which shows the structure of the partition metal fitting and plunger member in the vibration isolator shown by FIG. It is sectional drawing along the axial direction which shows the structure of the vibration isolator which concerns on 2nd Embodiment to this invention, and has shown the state which has a plunger member in an open position.

Explanation of symbols

10 Anti-vibration device 12 Outer cylinder fitting (first mounting member)
20 Mounting bracket (second mounting member)
24 Rubber elastic body (elastic body)
36 Partition bracket (support member)
40 Diaphragm 42 Main liquid chamber 44 Sub liquid chamber 70 Common orifice portion 72 Dedicated orifice portion 74 Orifice opening 76 Cylinder chamber 78 Plunger member 79 Edge portion 90 Coil spring (biasing member)
102 Valve body 118 Protrusion (leak prevention means)
119 Blocking surface (leak prevention means)
122 Shake orifice (first restricted passage)
124 Idle orifice (second restricted passage)
126 Hydraulic pressure release path 128 Check valve 130 Hydraulic pressure space 132 Orifice space 140 Vibration isolator 142 Hydraulic pressure release path 144 Blocking portion (leak prevention means)
146 Blocking surface (leak prevention means)

Claims (6)

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;
A main liquid chamber in which a liquid is sealed with the elastic body as a part of a partition wall, and the internal volume changes with elastic deformation of the elastic body;
A secondary liquid chamber in which liquid is enclosed and the internal volume can be expanded and contracted;
A first restricting passage communicating the main liquid chamber and the sub liquid chamber with each other;
A second restricting passage that connects the main liquid chamber and the sub liquid chamber to each other, and has a smaller flow resistance of the liquid than the first restricting passage;
A cylinder chamber provided between the main liquid chamber and the sub-liquid chamber and enclosing a liquid;
The cylinder chamber is partitioned into an orifice space that constitutes a part of the second restriction passage and communicates with the sub liquid chamber and a hydraulic space that is isolated from the second restriction passage, and the orifice space and A plunger member capable of moving between a predetermined open position and a closed position along the expansion / contraction direction of the hydraulic pressure space;
An orifice opening provided so as to face the orifice space, and communicating the orifice space with the other part of the second restriction passage;
A biasing member that biases the plunger member toward the open position that reduces the hydraulic pressure space;
The reverse is arranged between the main liquid chamber and the hydraulic pressure space, and the liquid can flow out only in one direction between the main liquid chamber and the hydraulic pressure space in accordance with the change of the hydraulic pressure in the main liquid chamber. A stop valve,
The liquid pressure space is communicated with the sub liquid chamber, and when the plunger member moves to the open position side by the urging force of the urging member, the flow amount of the liquid flowing inside is limited, A hydraulic pressure release path for allowing the liquid in the pressure space to flow into the auxiliary liquid chamber;
Leakage preventing means that closes the hydraulic pressure release path when the plunger member moves to the open position, and that opens the hydraulic pressure release path when the plunger member leaves the open position;
When the plunger member moves to the open position by the urging force of the urging member, the orifice opening is opened, and the blockage is performed against the urging force of the urging member by the hydraulic pressure in the hydraulic pressure space. A vibration isolator which closes the orifice opening when moved to a position. A guide shaft that extends along the expansion / contraction direction in the cylinder chamber and is slidably inserted into a bearing hole provided to penetrate the plunger member along the expansion / contraction direction;
Forming the hydraulic pressure release path through the guide shaft along the expansion / contraction direction,
When the plunger member moves to the open position, the leak preventing means is a closing member that presses against the peripheral edge of the opening end of the bearing hole on one end surface of the plunger member and closes the hydraulic pressure release path together with the bearing hole. The vibration isolator according to claim 1, wherein: Forming the hydraulic pressure release path so as to penetrate between one end face of the plunger member facing the hydraulic pressure space and the other end face of the plunger member facing the orifice space;
The leak preventing means has a closing member that presses against a peripheral edge of the opening end of the hydraulic pressure release path on one end face of the plunger member to close the hydraulic pressure release path when the plunger member moves to the open position. The vibration isolator according to claim 1.   4. The vibration isolator according to claim 2, wherein the closing member is made of an elastic material. The check valve is provided in a partition wall partitioning the main fluid chamber and the hydraulic space, and has a valve seat opening for communicating the main fluid chamber and the hydraulic space, and a peripheral portion of the valve seat opening. And a valve body made of an elastic material that comes into contact with and separates from the peripheral edge of the valve seat opening in accordance with a change in hydraulic pressure in the main liquid chamber.
The vibration isolator according to claim 4, wherein the closing member is formed integrally with the valve body.   6. The prevention according to claim 2, wherein the blocking member is disposed on an inner wall portion that forms one end face on the hydraulic pressure space side along the expansion / contraction direction in the cylinder chamber. Shaker.

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