JP4648155B2 - Vibration isolator - Google Patents

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. At the same time, 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 during the idle vibration. An anti-vibration device is disclosed that moves an idle orifice to an open position by an urging force.

  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.
International Publication WO 2004/081408

  By the way, in the vibration isolator described in Patent Document 1, when shake vibration is input, the plunger member moves from the open position to the closed position, and during the input of shake vibration, the plunger member is continuously moved by the hydraulic pressure in the hydraulic pressure space. The orifice is held in the closed position, and the orifice opening is completely closed by the plunger member.

  However, in the vibration isolator as in Patent Document 1, when the input vibration is changed from the shake vibration to the idle vibration in accordance with the change of the driving state from the running state of the vehicle to the stop state, the orifice opening (idle orifice) is opened. In the completely closed state (shake mode), even if the input vibration changes from shake vibration to idle vibration, the fluid pressure (hydraulic pressure amplitude) in the main fluid chamber remains relatively high. The biasing force of the coil spring that biases the plunger member toward the open position may not be sufficiently large with respect to the holding force for holding the plunger member generated by the hydraulic pressure in the hydraulic pressure space in the closed position. .

  Therefore, in the vibration isolator as in Patent Document 1, if the hydraulic pressure amplitude in the main liquid chamber is not sufficiently small, the plunger member in the closed position does not start moving toward the open position due to the biasing force of the coil spring, or There may be a problem that the time required to start the movement (response time) is delayed and the time required for the idle orifice to change from the closed state to the open state increases.

  The object of the present invention is to take into account the above facts and delay the time until the plunger member in the closed position moves to the open position when the input vibration changes from a relatively low frequency vibration to a high frequency vibration. An object of the present invention is to provide an anti-vibration device that can prevent this.

  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 space, and when the plunger member returns to the open position by the biasing force of the biasing member, Liquid in the pressurized space A hydraulic pressure release passage for allowing the orifice space to flow into the orifice space or the sub-liquid chamber, and an auxiliary opening provided so as to face the orifice space and communicating the orifice space with the other portion in the second restriction passage; When the plunger member moves to the open position by the urging force of the urging member, the orifice opening is opened and the urging force of the urging member is resisted by the hydraulic pressure in the hydraulic pressure space. Then, when moving to the closed position, the orifice opening is closed, the vibration in the expansion / contraction direction is vibrated in accordance with a change in the hydraulic pressure in the main liquid chamber, and the auxiliary opening is periodically opened and closed. To do.

  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. At this time, 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 moves from the open position to the closed position side against the urging force of the urging member. It moves intermittently and is held at 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 the hydraulic pressure in the hydraulic pressure space reaches an equilibrium pressure that substantially balances 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, it is possible to effectively reduce high-frequency vibrations transmitted from the vibration generating unit to the vibration receiving unit.

  At this time, if 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, the main liquid chamber and the sub liquid chamber pass through the second restriction passage. Since a resonance phenomenon (liquid column resonance) occurs in the liquid flowing back and forth, the high frequency region vibration can be particularly effectively absorbed by the action of the liquid column resonance.

  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 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 moves to the closed position against the urging force of the urging member by the hydraulic pressure in the hydraulic pressure space, the plunger member is moved when the low-frequency vibration is input. When moving to the closed position, liquid in the pressurized or depressurized state of the main liquid chamber is intermittently supplied (discharged) into the hydraulic pressure space through the check valve, but at a time when the liquid is not supplied (discharged). Since the hydraulic pressure in the pressurized space is changed by being pressurized or depressurized by the plunger member that receives the biasing force from the biasing member, the hydraulic pressure in the hydraulic pressure space is synchronized with the hydraulic pressure change in the main fluid chamber. As a result, a phenomenon that periodically changes occurs.

  Thereby, a plunger member vibrates along the expansion / contraction direction with the periodic hydraulic pressure change in hydraulic pressure space, maintaining a balance with the urging | biasing force from an urging | biasing member. At this time, if the auxiliary opening is arranged in a portion overlapping with a part of the vibration range of the plunger member, the plunger member moved to the closed position vibrates in synchronization with the low frequency vibration, and the auxiliary opening Open or close some or all of them periodically (intermittently).

  Therefore, in the vibration isolator according to the first aspect, when the plunger member moves to the closed position at the time of inputting the low frequency vibration, the auxiliary opening is moved by the plunger member within a predetermined period (shorter than one cycle) within one cycle. Therefore, when the auxiliary opening is opened, the main liquid chamber and the auxiliary liquid chamber are passed through the second restricting passage where the liquid flow is restricted by the auxiliary opening and the plunger member. And communicate in a limited way.

  As a result, according to the vibration isolator according to claim 1, even if the plunger member moves to the closing position and closes the orifice opening at the time of inputting the low-frequency vibration, the auxiliary opening is periodically synchronized with the input vibration. If the opening area and opening time of the auxiliary opening opened by the plunger member are appropriately adjusted, the change in the hydraulic pressure in the main liquid chamber can be controlled to be reduced by a desired amount. When the vibration is changed from the low-frequency vibration to the high-frequency vibration, the plunger member can be easily returned to the open position even if the urging force of the urging member that urges the plunger member toward the open position is small.

  As a result, when the input vibration changes from low frequency vibration to high frequency vibration, the time (response time) from when the input vibration changes to idle vibration until the plunger member starts to move to the open position side is sufficient. Since it can be shortened, the time required for the plunger member to change the second restriction passage from the closed state to the open state can be effectively shortened.

  A vibration isolator according to claim 2 of the present invention is the vibration isolator according to claim 1, wherein a part of the first restricting passage on the main liquid chamber side is a part of the second restricting passage. And the other part of the first restriction passage on the side of the secondary liquid chamber is configured as a dedicated orifice part, and the auxiliary opening provides the orifice space to the shared orifice part. It is characterized by making it communicate.

  A vibration isolator according to claim 3 of the present invention is the vibration isolator according to claim 1 or 2, wherein the orifice opening is opened in the inner peripheral surface of the cylinder chamber, and the plunger member is in the closed position. At a certain time, a part of the plunger member is overlapped with a peripheral edge portion of the orifice opening on the inner peripheral surface of the cylinder chamber along the expansion / contraction direction, and the plunger member and the inner peripheral surface of the cylinder chamber overlap each other. The width of the region along the expansion / contraction direction is made larger than the amplitude of the plunger member that vibrates in the expansion / contraction direction in accordance with the change in the hydraulic pressure in the main liquid chamber.

  The vibration isolator according to claim 4 of the present invention is the vibration isolator according to claim 3, wherein the auxiliary opening has one end opened to the plunger-side overlap region of the plunger member and the other end. The part is opened so as to face the orifice space.

  The vibration isolator according to claim 5 of the present invention is the vibration isolator according to claim 3, wherein one end of the auxiliary opening is opened to the opening-side overlap on the inner peripheral surface of the cylinder chamber. The other end is opened so as to face the first restriction passage.

  A vibration isolator according to claim 6 of the present invention is the vibration isolator according to any one of claims 1 to 5, wherein the first attachment member is formed in a substantially cylindrical shape, and the first attachment A liquid chamber space partitioned from the outside with the elastic body and the diaphragm as a part of the partition is provided on the inner peripheral side of the member, and the elastic body is part of the partition in the liquid chamber space. A partition member for partitioning the main liquid chamber and the sub-liquid chamber in which the diaphragm is a part of the partition wall is provided, and a part of the second restriction passage is provided on the partition member along the outer peripheral surface In addition, the cylinder chamber is provided on the inner peripheral side of the partition member.

  As described above, according to the vibration isolator according to the present invention, when the input vibration is relatively changed from the low-frequency vibration to the high-frequency vibration, the plunger member at the closed position moves to the open position. Can be prevented from being delayed.

  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 tube member 12 so as to be bent toward the outer peripheral side, and a caulking portion 16 is formed at the lower end portion so as to be bent in a tapered shape toward the inner peripheral side when the apparatus is assembled. In the middle of the flange portion 14 and the caulking portion 16, a throttle portion 18 bent in a V-shaped cross section toward the inner peripheral side is formed over the entire circumference. 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 upper end side of the mounting bracket 20 is formed in a columnar shape having a substantially constant outer diameter, and the lower end side is formed in a substantially truncated cone shape whose outer diameter is reduced in a tapered shape downward. A screw hole 22 is drilled in the metal fitting 20 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 22 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 has an outer peripheral surface vulcanized and bonded to the upper side of the narrowed portion 18 on the inner peripheral surface of the outer cylinder fitting 12, and an inner peripheral surface is vulcanized and bonded to the lower end side of the outer peripheral surface of the mounting bracket 20. Yes. 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 at the center 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 from the outer peripheral portion of the upper end to the outer peripheral side. The stopper section 28 is a peripheral portion of the flange portion 14 of the outer cylinder fitting 12. It is vulcanized and bonded to a part along the direction. The stopper 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. At the same time, the generation of collision noise is prevented.

  The rubber elastic body 24 is integrally formed with an inner cushion portion 30 that covers the lower end portion of the mounting bracket 20 on the inner peripheral portion of the lower end thereof, and a step portion 32 on the inner peripheral side of the throttle portion 18 of the outer cylindrical bracket 12. Are integrally formed. The stepped portion 32 has a flat bottom surface and is supported by the throttle portion 18 so that deformation in the axial direction from the outer peripheral side is limited. The rubber elastic body 24 is integrally formed with a thin cylindrical covering portion 34 that extends downward from the outer peripheral portion of the lower end of the step portion 32. The covering portion 34 is extended to the lower end so as to cover the inner peripheral surface of the outer cylinder fitting 12 and is vulcanized and bonded to the outer cylinder fitting 12.

  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 its outer peripheral surface on the upper surface side of the stepped portion 32 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 metal 36 on the inner peripheral side of the outer cylinder metal 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 synthetic resin or aluminum on the lower side thereof, and a bottomed cylindrical shape is formed on the upper side of the orifice member 46. A lid member 48 is disposed. 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 boss portion 54 has a dimension along the axial direction larger than the thickness of the bottom plate portion 50 and protrudes from the upper surface portion and the lower surface portion 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. The boss portion 54 is provided with a clearance hole 58 penetrating between the bottom surface of the seat receiving hole 56 and the lower surface of the boss portion 54. The inner diameter of the escape hole 58 is smaller than the inner diameter of the seat receiving hole 56, and a guide cylinder portion 82 of a plunger member 78 described later is inserted into the escape hole 58 in a detachable manner.

  As shown in FIG. 5, the orifice member 46 is formed with a fitting insertion portion 60 having an outer diameter smaller than that of the lower end side at the upper end portion of the outer peripheral surface thereof. The orifice member 46 is formed with a concave groove portion 64 extending along a spiral direction inclined at a predetermined angle with respect to the circumferential direction between the step portion 62 and the lower end portion on the outer peripheral surface.

  In the orifice member 46, as shown in FIG. 6B, a part of the fitting insertion portion 60 is cut out in a concave shape in the axial direction, and one end portion on the main liquid chamber 42 side along the longitudinal direction of the groove portion 64 is formed. Is formed to communicate with the upper surface of the orifice member 46. Further, as shown in FIG. 6C, the orifice member 46 is partially cut out in a rectangular shape in the axial direction, and the other end portion along the longitudinal direction of the groove portion 64 is the orifice member 46. A communication path 68 is formed to communicate with the lower surface of the communication path.

  The groove portion 64 is provided with a common orifice portion 70 in a section from one end on the main liquid chamber 42 side to the middle portion in the longitudinal direction (spiral direction), and a dedicated orifice on the sub liquid chamber 44 side with respect to the common orifice portion 70. A portion 72 is provided. Here, the common orifice portion 70 and the dedicated orifice portion 72 have the same depth along the radial direction, but the common orifice portion 70 has a width along the axial direction of the axis of the dedicated orifice portion 72. It is longer than the width along the direction by a predetermined length. As a result, the common orifice portion 70 has a cross-sectional area larger than the cross-sectional area of the dedicated orifice portion 72, and the cross-sectional area of the common orifice portion 70 is the frequency of idle vibration (for example, 18) generated during idling operation of the vehicle. To 30 Hz) and amplitude. Further, the path length of the common orifice portion 70 is set to be ½ or less of the dimension (path length) along the longitudinal direction of the groove portion 64.

  As shown in FIG. 6 (A), the orifice member 46 is located near the boundary between the common orifice portion 70 and the dedicated orifice portion 72 in the groove portion 64 on the inner peripheral side of the groove portion 64 (vibration absorbing orifice portion 70). An orifice opening 74 penetrating from the bottom surface portion to the inner peripheral surface of the orifice member 46 is formed. The orifice opening 74 is formed in a slot shape elongated in the circumferential direction. Here, the opening area of the orifice opening 74 is equal to or larger than the cross-sectional area of the common orifice portion 70.

  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. 6A, the orifice member 46 is formed with an auxiliary opening 134 that extends downward from the central portion in the longitudinal direction on the lower end side of the orifice opening 74. Similarly to the orifice opening 74, the auxiliary opening 134 penetrates along the radial direction from the bottom surface portion of the common orifice portion 70 to the inner peripheral surface of the orifice member 46, and the cross-sectional shape thereof is the orifice opening 74 side (upper end side). ) Is formed in an open U shape. A length H along the axial direction of the auxiliary opening 134 is smaller than an overlap amount OL (see FIG. 4) with respect to the orifice opening 74 of the plunger member 78 at the closing position described later.

  As shown in FIG. 6C, 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. . As shown in FIG. 5, the plunger member 78 is formed in a thick disk shape, and a hydraulic space 130 (FIG. 3) that is a small space on the main liquid chamber 42 side along the axial direction of the cylinder chamber 76. And an orifice space 132 (see FIG. 4), which is a small space on the side of the auxiliary liquid chamber 44. 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 recess 80 extending in the circumferential direction between the peripheral portion and the central portion on the lower surface side. The plunger member 78 is integrally formed with a thick cylindrical guide tube portion 82 projecting downward from the center portion of the lower surface thereof, and a bearing hole penetrating the center portion of the guide tube portion 82 in the axial direction. 84 is drilled. The plunger member 78 is coaxially formed with a cylindrical seat receiving portion 86 having a diameter larger than that of the guide tube portion 82 at the base end portion of the guide tube portion 82. The plunger member 78 is formed with a circular concave relief 88 at the center of the upper surface thereof.

  As shown in FIG. 3, the plunger member 78 is inserted into the cylinder chamber 76 of the orifice member 46 and is movable (slidable) in the axial direction along the inner peripheral surface of the cylinder chamber 76. At this time, the plunger member 78 is coaxially inserted into the seat receiving hole 56 and the escape hole 58 of the orifice member 46 at the front end side of the guide tube portion 82, but the outer diameter of the guide tube portion 82 is set to the seat receiving hole. 56 and the inner diameter of the escape hole 58, the plunger member 78 is not in contact with the bottom plate portion 50 of the orifice member 46, and has a predetermined range along the axial direction (a closed position and an open position described later). Between). In addition, 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 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 fitted and fixed to the outer peripheral side of the fitting portion 60 in the orifice member 46. As a result, the upper end side of the cylinder chamber 76 of the orifice member 46 is closed by the top plate portion 92 of the lid member 48. As shown in FIG. 5, the lid member 48 has a circular insertion hole 94 formed in the center of the top plate portion 92, and a plurality of fan-shaped holes formed on the outer peripheral side of the insertion hole 94. In the present embodiment, 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 is formed with a notch 98 on its outer peripheral portion so as to face the communication path 66 (see FIG. 6B) on the upper end side of the orifice member 46. . The common orifice part 70 communicates with the sub liquid chamber 44 through the notch part 98 and the communication path 66 of the lid member 48.

  As shown in FIG. 5, 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 between the holder member 100 and the lid member 48. A substantially disc-shaped valve body 102 is interposed between the two. 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. 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.

  As shown in FIG. 3, the holder member 100 is integrally formed with a thick disc-shaped boss portion 110 at the center portion of the bottom plate portion 105, and an axial center from the bottom surface center portion of the boss portion 110. A round rod-shaped guide rod 120 protruding downward along S is integrally formed. A circular concave fitting insertion hole 112 is formed on the upper surface side of the boss portion 110. Here, between the top plate portion 92 of the lid member 48 and the bottom plate portion 105 of the holder member 100, a valve body that is a disk-shaped space having a constant thickness along the axial direction on the outer peripheral side of the fitting insertion hole 112. A storage chamber 114 is formed, and the valve body 102 is stored in the valve 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. 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. 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.

  The valve body 102 is compressed in the axial direction between the top plate portion 92 of the lid member 48 and the bottom plate portion 105 of the holder member 100 in the vicinity of the peripheral portions of the projections 116 and 118. As a result, the upper surface portion of the valve body 102 is pressed against the lower surface side of the top plate portion 92 of the lid member 48 with a predetermined pressure (preload), and between the lid member 48 and the holder member 100 in the axial direction. The movement of is restricted. In the valve body 102, a portion on the outer peripheral side of the compressed portion can be bent and deformed 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 in a state where the upper surface portion thereof is in pressure contact with the top plate portion 92 (closed state), and the outer peripheral side is downward as shown by a two-dot chain line in FIG. The valve seat opening 96 communicates with the communication opening 108 via the valve body storage chamber 114, and the main liquid chamber 42 is in the valve body storage chamber. 114 communicates with the cylinder chamber 76 in the partition metal 36. 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 guide rod 120 of the holder member 100 is inserted into the bearing hole 84 of the plunger member 78 so as to be relatively slidable along the axial direction. Here, when one of the guide cylinder portion 82 and the guide rod 120 in which the bearing hole 84 is formed is made of metal, the other is a material whose Young's modulus such as resin is different by a predetermined value or more and whose friction resistance is small. It is preferable to form by. In addition, one or both of the inner peripheral surface of the bearing hole 84 and the outer peripheral surface of the guide rod 120 may be coated with a material having lubricity and high wear resistance to suppress frictional resistance during sliding. . Further, the guide rod 120 protrudes to the lower side of the orifice member 46 through the seat receiving portion 86 and the escape hole 58 of the orifice member 46 at the tip side.

  The orifice space 132 of the cylinder chamber 76 is always in communication with the auxiliary liquid chamber 44 through the plurality of flow openings 52 of the orifice member 46, the seat receiving portion 86 and the escape hole 58. Further, in the vibration isolator 10, as shown in FIG. 1, the outer peripheral side of the groove portion 64 in the orifice member 46 is blocked by the inner peripheral surface of the outer cylindrical metal member 12 through the covering portion 34. As a result, a shake orifice 122 that is an elongated space along the spiral direction is formed in the groove portion 64 as a first restriction passage, and one end portion of the shake orifice 122 has a communication passage 66 of the orifice member 46 and a lid. The other end of the member 48 is connected to the sub liquid chamber 44 through the communication path 68 of the orifice member 46 while being connected to the main liquid chamber 42 through the notch 98 of the member 48.

  Here, the shake orifice 122 is configured by the entire groove portion 64 including the common orifice portion 70 and the dedicated orifice portion 72 having different cross-sectional areas and the communication passages 66 and 68. The shake orifice 122 has a path length and a cross-sectional area, that is, a liquid flow resistance, set so as to correspond to a shake vibration (for example, 9 to 15 Hz) that is a relatively low frequency vibration of the input vibration. Tuning).

  The common orifice part 70 in the groove part 64 forms a part of the idle orifice 124 corresponding to idle vibration (for example, 18 to 30 Hz) that is vibration in a high frequency range relatively to the shake vibration. The idle orifice 124, which is the second restriction passage, is configured by the common orifice portion 70, the orifice opening 74, and the orifice space 132 in the orifice member 46, and its path length and cross-sectional area, that is, the flow resistance of the liquid is idle vibration. It is set (tuned) to correspond to. Here, 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.

  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 common orifice portion 70 is The orifice space 132 is not in communication. 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 overlap area AP which is the lower end side area on the outer peripheral surface of the plunger member 78 is changed from the overlap area AW which is the lower area of the orifice opening 74 on the inner peripheral surface of the cylinder chamber 76 along the axial direction. Position (overlap) on the inner circumference side. At this time, the overlap amount OL, which is the length along the axial direction between the overlap area AP and the overlap area AW, is set to about 2.5 to 3.0 mm, for example. By overlapping the overlap area AP of the plunger member 78 and the overlap area AW of the cylinder chamber 76 with the plunger member 78 in the closed position in this way, as described later, Even if the plunger member 78 vibrates with a small amplitude along the axial direction as the hydraulic pressure changes, the orifice opening 74 can be reliably maintained in the closed state by the plunger member 78.

  Here, since the overlap amount OL of the overlap region AW on the cylinder chamber 76 side is larger than the length H along the axial direction of the auxiliary opening 134, the auxiliary opening 134 has an inner peripheral side. The end portion opens in the overlap area AW.

  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, When the liquid that has flowed into the common orifice portion 70 reaches the vicinity of the boundary with the dedicated orifice portion 72, the liquid preferentially enters the orifice space 132 through the orifice opening 74 having a smaller flow resistance than the dedicated orifice portion 72. In addition, the liquid flowing into the common orifice part 70 through the orifice opening 74 preferentially passes through the common orifice part 70 whose liquid flow resistance is smaller than that of the dedicated orifice part 72 and into the main liquid chamber 42. Exit. 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.

  As shown in FIG. 3, the plunger member 78 is formed with a plurality of (two in the present embodiment) hydraulic pressure release passages 126 penetrating in the axial direction at the radial intermediate portion thereof. These hydraulic pressure release paths 126 allow the liquid in the hydraulic pressure space 130 closed from the outside to flow into the orifice space 132 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 plunger member 78 can be moved to the open position side by preventing the hydraulic pressure in the hydraulic pressure space 130 from rising.

  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.

  Further, in the vibration isolator 10, a part of the shake orifice 122 on the main liquid chamber 42 side is the common orifice part 70 that forms a part of the idle orifice 124, and the sub-liquid chamber in the common orifice part 70 and the shake orifice 122. Since the orifice opening 74 communicating with the orifice space 132 of the cylinder chamber 76 is formed between the dedicated orifice portion 72 which is a part on the side of the cylinder 44, the main liquid chamber 42 and the sub liquid chamber 44 are used as the common orifice portion. 70 and a shake orifice 122 including a dedicated orifice portion 72 and communicate with each other via an idle orifice 124 including a common orifice portion 70 and an orifice space 132.

  Further, 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 the coil spring 90 returns to the open position from the closed position due to the urging force, the orifice opening 74 is opened, so that the plunger member 78 in the open position passes through the check valve 128 from the main fluid chamber 42 into the hydraulic pressure space 130. When the liquid is supplied to the closed position, the liquid moves back and forth between the main liquid chamber 42 and the sub liquid chamber 44 only through the shake orifice 122 with the elastic deformation of the rubber elastic body 24. When the plunger member 78 in the closed position returns to the open position by the biasing force of the coil spring 90, the shake orifice 122 and Both of the idle orifices 124 are opened, but with the elastic deformation of the rubber elastic body, the main liquid chamber 42 and the auxiliary liquid chamber preferentially pass through the idle orifice 124 with 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.

  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 hydraulic pressure release path 126 formed in the plunger member 78 is closed from the outside in the hydraulic pressure space 130. Since the liquid inside flows out into the orifice space 132, the hydraulic pressure in the hydraulic space 130 is prevented from rising, and the plunger member 78 can be moved smoothly toward the open position with low movement resistance.

  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 moves to the closed position against the urging force of the coil spring 90 by the hydraulic pressure in the hydraulic pressure space 130 when the shake vibration is input, Although the pressurized liquid in the main liquid chamber 42 is intermittently supplied through the check valve 128, the liquid pressure in the hydraulic pressure space 130 is supplied from the coil spring 90 when no liquid is supplied from the main liquid chamber 42. Therefore, a phenomenon occurs in which the hydraulic pressure in the hydraulic pressure space 130 periodically changes in synchronization with the change in the hydraulic pressure in the main fluid chamber 42.

  As a result, the plunger member 78 vibrates with a minute amplitude along the axial direction in accordance with a periodic hydraulic pressure change in the hydraulic pressure space 130 while maintaining a balance with the urging force from the coil spring 90. At this time, since the auxiliary opening 134 is arranged at a portion where it overlaps with a part of the vibration range of the plunger member 78, the plunger member 78 moved to the closed position vibrates in synchronization with the shake vibration, and also assists. A part of the opening 134 is opened and closed periodically (intermittently).

  Therefore, in the vibration isolator 10, when the plunger member 78 moves to the closed position during the input of the shake vibration, the plunger member 78 causes the auxiliary opening 134 to move through a predetermined period within one cycle of the input vibration (a time interval shorter than one cycle). Therefore, during the period in which the auxiliary opening 134 is opened, the main liquid chamber 42 and the auxiliary liquid 42 are connected to the auxiliary liquid 134 through the idle orifice 124 in which the liquid flow is restricted by the auxiliary opening 134 and the plunger member 78. The liquid chamber 44 communicates restrictively.

  As a result, according to the vibration isolator 10 according to the present embodiment, even if the plunger member 78 moves to the closing position and closes the orifice opening 74 when the shake vibration is input, it is synchronized with the input vibration (shake vibration). If the opening area and opening time of the auxiliary opening 134 opened by the plunger member 78 are appropriately adjusted by periodically opening the auxiliary opening 134, the change in the hydraulic pressure in the main liquid chamber 42 can be reduced by a desired amount. Since the hydraulic pressure in the hydraulic pressure space 130 increases or decreases according to the magnitude (pressure amplitude) of the hydraulic pressure change in the main fluid chamber 42, the input vibration changes from the shake vibration to the idle vibration. In this case, even if the biasing force of the coil spring 90 that biases the plunger member 78 toward the open position is small, the plunger member 78 can be easily returned to the open position.

  Thereby, when the input vibration changes from the shake vibration to the idle vibration, the time (response time) from when the input vibration changes to the idle vibration until the plunger member 78 starts to move to the open position side is sufficiently short. Therefore, the time required until the idle orifice 124 is changed from the closed state to the open state by the plunger member 78 can be effectively shortened.

  In the vibration isolator 10 according to the present embodiment, the main liquid chamber 42 side of the groove portion 64 on the outer peripheral surface of the orifice member 46 is used as the common orifice portion 70, and the sub liquid chamber 44 side is used as the dedicated orifice portion 72. Although the orifice portion 70 is shared by the shake orifice 122 and the idle orifice 124, another groove portion separated from the groove portion forming the shake orifice 122 is formed in the orifice member 46, and this another groove portion is used as one of the idle orifices 124. You may make it be a part.

  In the above description of the present embodiment, as shown in FIG. 6, the auxiliary opening 134 has been described as being formed by cutting the lower end side of the orifice opening 74 into a U shape. As described above, the auxiliary opening 136 may be formed in the orifice member 46 so as to have a through hole shape separated from the orifice opening 74. The orifice opening 74 penetrates from the inner peripheral surface of the orifice member 46 to the bottom surface portion of the common orifice portion 70, and the inner peripheral end thereof opens into the overlap region AW on the cylinder chamber 76 side. ing. Even when such an auxiliary opening 136 is provided in the orifice member 46, the auxiliary opening 136 can be periodically opened by the plunger member 78 when a shake vibration is input, whereby the liquid pressure in the main liquid chamber 42 is increased. Since the change can be controlled to be reduced by a desired amount, when the input vibration is changed from the shake vibration to the idle vibration, the change in the hydraulic pressure in the main liquid chamber 42 caused by the input of the idle vibration can be reduced. It can be certainly smaller than the input.

(Second Embodiment)
8 and 9 show 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 an auxiliary opening 142 is provided in the plunger member 78. That is, as shown in FIG. 9, a plurality (six in this embodiment) of auxiliary openings 142 are formed in the plunger member 78 along the lower end of the cylindrical peripheral wall portion 81. These auxiliary openings 142 are formed by cutting the peripheral wall portion 81 into a U shape from the lower end to the upper end side, and the auxiliary openings 142 are equally spaced (60 ° intervals) along the circumferential direction. Are arranged in Here, the auxiliary opening 142 has an end on the outer peripheral side that opens into the overlap region AP of the plunger member 78.

  The length H along the axial direction of the auxiliary opening 142 is smaller than the overlap amount OL (see FIG. 4) of the plunger member 78 with respect to the orifice opening 74, like the auxiliary opening 134 according to the first embodiment. Yes. The distance along the circumferential direction between the pair of adjacent auxiliary openings 142 is substantially equal to the dimension along the circumferential direction of the orifice opening 74. Thereby, even if the plunger member 78 is at an arbitrary position along the rotation direction about the axis S, at least one auxiliary opening 142 coincides with the orifice opening 74 along the circumferential direction, and two When the auxiliary openings 142 partially coincide with the orifice openings 74 along the circumferential direction, the total area (effective opening area) of the portions where the two auxiliary openings 142 overlap the orifice openings 74 is one. The total opening area of the auxiliary opening 142 is substantially equal.

  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 moves to the closed position when shake vibration is input, the plunger member 78 vibrates in accordance with a change in hydraulic pressure in the hydraulic pressure space 130, thereby causing the auxiliary opening 142 to input vibration. Since it is possible to communicate with the orifice opening 74 only during a predetermined period within one cycle (a time interval shorter than one cycle), the auxiliary opening 142 is communicated with the orifice opening 74 during the period during which the auxiliary opening 142 communicates with the orifice opening 74. In addition, the main liquid chamber 42 and the sub liquid chamber 44 communicate in a limited manner through the idle orifice 124 in which the liquid flow is restricted by the plunger member 78.

  As a result, according to the vibration isolator 140 according to the present embodiment, even if the plunger member 78 moves to the closing position and closes the orifice opening 74 when the shake vibration is input, it is synchronized with the input vibration (shake vibration). If the opening area and the opening time of the auxiliary opening 134 when communicating with the orifice opening 74 are appropriately adjusted by periodically communicating the auxiliary opening 142 with the orifice opening 74, a change in the hydraulic pressure in the main liquid chamber 42 is desired. Since the hydraulic pressure in the hydraulic pressure space 130 increases or decreases in accordance with the magnitude (pressure amplitude) of the hydraulic pressure change in the main fluid chamber 42, the input vibration can be controlled from the shake vibration. The plunger member 7 that generates the biasing force of the coil spring 90 that biases the plunger member 78 to the open position side due to the hydraulic pressure in the hydraulic pressure space 130 when it changes to idle vibration. It is possible to sufficiently increase the holding force to be held in the closed position.

  Thereby, when the input vibration changes from the shake vibration to the idle vibration, the time (response time) from when the input vibration changes to the idle vibration until the plunger member 78 starts to move to the open position side is sufficiently short. Therefore, the time required until the idle orifice 124 is changed from the closed state to the open state by the plunger member 78 can be effectively shortened.

  In the above description of the present embodiment, as shown in FIG. 9, the auxiliary opening 142 is formed by cutting the peripheral wall portion 81 of the plunger member 78 upward from its lower end in a U shape. As described above, as shown in FIG. 10, such an auxiliary opening 144 may be formed in the peripheral wall portion 81 of the plunger member 78 so as to have a through hole shape penetrating the peripheral wall portion 81 along the radial direction. good. The auxiliary opening 144 also has an outer peripheral end that opens into the overlap region AP of the plunger member 78. Even when such an auxiliary opening 144 is provided in the plunger member 78, the auxiliary opening 144 can be periodically communicated with the orifice opening 74 by the vibration of the plunger member 78 when a shake vibration is input. Since the fluid pressure change in the chamber 42 can be controlled to be reduced by a desired amount, when the input vibration changes from the shake vibration to the idle vibration, the liquid in the main liquid chamber 42 generated by the input of the idle vibration The pressure change can be surely made smaller than when shake vibration is input.

(Third embodiment)
FIG. 11 shows a vibration isolator according to a third embodiment of the present invention. In the vibration isolator 150 according to the present embodiment, the same parts as those in the vibration isolator 10 according to the first embodiment are denoted by the same reference numerals, and description thereof is omitted.

  The vibration isolator 150 according to this embodiment is different from the vibration isolator 10 according to the first embodiment in that a valve seat opening 152 is formed in the bottom plate portion 105 of the holder member 100 and the top plate portion 92 of the lid member 48 is formed. In the valve body storage chamber 114, the valve body 158 constituting the check valve 156 together with the lid member 48 and the holder member 100 is turned upside down so as to come into pressure contact with the bottom plate portion 105. It is a point that is stored.

  Furthermore, in the vibration isolator 150, a coil spring 160 in a compressed state is interposed between the bottom plate portion 105 and the plunger member 162, and the coil spring 160 always moves the plunger member 162 downward (in the present embodiment, the open position). Side). The plunger member 162 is formed with a plunger opening 164 penetrating from the outer peripheral surface to the inner peripheral surface of the annular recess 80, and the plunger opening 162 contacts the bottom plate portion 50 of the orifice member 48. When in the open position, it is held at the same position as the orifice opening 74, and the common orifice portion 70 communicates with the orifice opening 74 in the orifice space 132. Further, when the plunger member 162 moves from the open position to the closing position where the compression limit of the coil spring 160 is reached, the orifice opening 74 is closed by the outer peripheral surface thereof.

  Note that in the vibration isolator 150 according to the present embodiment, the plunger member 162 has a portion on the lower end side of the inner peripheral surface of the plunger opening 164 cut into a U shape to form an auxiliary opening 166. Such an auxiliary opening may be formed on the orifice member 46 side by cutting away a part of the upper end side of the inner peripheral surface of the orifice opening 74.

  Next, the operation of the vibration isolator 150 according to the embodiment of the present invention will be described.

  In the vibration isolator 150, when the fluid pressure in the main fluid chamber 42 becomes negative with respect to the fluid pressure in the fluid pressure space 130, the valve body 158 opens the valve seat opening 152, and the fluid in the main fluid chamber 42. When the pressure becomes substantially equal to or positive with the hydraulic pressure in the hydraulic pressure space 130, the valve seat opening 152 is closed. As a result, the hydraulic pressure in the hydraulic pressure space 130 is reduced to a pressure balanced with the lower limit value of the hydraulic pressure in the main fluid chamber 42 when vibration is input.

  Therefore, in the vibration isolator 150, 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 out from the hydraulic pressure space 130 into the main hydraulic chamber 42 through the check valve 156 when the hydraulic pressure in the main hydraulic chamber 42 periodically decreases, and the hydraulic pressure in the hydraulic pressure space 130 also increases. The pressure in the main liquid chamber 42 drops to an equilibrium pressure that is substantially in equilibrium with the rising liquid pressure.

  Here, also in the vibration isolator 150, the urging force of the coil spring 160 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. At the time of vibration input, the plunger member 162 intermittently moves from the open position to the closed position side against the biasing force of the coil spring, and is held at the closed position by the hydraulic pressure (negative pressure) in the hydraulic pressure space 130. .

  Therefore, in the vibration isolator 150, when 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 122 tuned to cope with the vibration, the shake vibration transmitted from the engine side to the vehicle body side can be reduced. .

  In the vibration isolator 150, 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 out from the hydraulic pressure space 130 to the main hydraulic chamber 42 through the check valve 156 when the hydraulic pressure in the main hydraulic chamber 42 periodically rises, and the hydraulic pressure space 42 The hydraulic pressure in 130 decreases and reaches an equilibrium pressure that is substantially in equilibrium with the hydraulic pressure (lower limit value) at the time of rising in the main liquid chamber 42.

  However, in the vibration isolator 150, the urging force of the coil spring 160 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, so that the plunger member 162 is in the open position. If the coil spring 160 is in the closed position, the coil spring 160 is moved (returned) from the closed position to the open position by the biasing force of the coil spring 160.

  Therefore, in the vibration isolator 150, 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 moves between the secondary liquid chamber 44 and the auxiliary liquid chamber 44, the input vibration (idle vibration) can be absorbed by the viscous resistance, pressure loss, etc. of the liquid flowing through the idle orifice 124 tuned to cope with the idle vibration. Therefore, idle vibration transmitted from the engine side to the vehicle body side can be reduced.

  As a result, even with the vibration isolator 150 according to the present embodiment, the main liquid chamber 42 and the sub liquid chamber can be used 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 communicating with 44 can be switched to one of the shake orifice 122 and the idle orifice 124 using the change in the hydraulic pressure in the main fluid chamber 42 as a driving force in accordance with the frequency of the input vibration.

  In the vibration isolator 150, when the plunger member 162 moves to the closed position against the urging force of the coil spring 160 by the hydraulic pressure in the hydraulic pressure space 130 when the shake vibration is input, Although the pressurized liquid in the main liquid chamber 42 is intermittently supplied through the check valve 128, the liquid pressure in the hydraulic pressure space 130 is supplied from the coil spring 160 when no liquid is supplied from the main liquid chamber 42. Therefore, a phenomenon occurs in which the fluid pressure in the fluid pressure space 130 periodically changes in synchronization with the fluid pressure change in the main fluid chamber 42.

  As a result, the plunger member 162 vibrates with a minute amplitude along the axial direction along with the periodic hydraulic pressure change in the hydraulic pressure space 130 while maintaining a balance with the urging force from the coil spring 160. At this time, since the auxiliary opening 166 is arranged at a portion where it overlaps with a part of the vibration range of the plunger member 162, the plunger member 162 moved to the closed position vibrates in synchronization with the shake vibration, and the auxiliary A part of the opening 166 is opened and closed periodically (intermittently).

  Therefore, in the vibration isolator 150, when the plunger member 162 moves to the closed position when the shake vibration is input, the plunger member 162 causes the auxiliary opening 166 to move through a predetermined period within one cycle of the input vibration (a time interval shorter than one cycle). In the period when the auxiliary opening 166 is opened, the main liquid chamber 42 and the auxiliary liquid 42 are connected through the idle orifice 124 in which the liquid flow is restricted by the auxiliary opening 166 and the plunger member 162. The liquid chamber 44 communicates restrictively.

  As a result, according to the vibration isolator 150 according to the present embodiment, even if the plunger member 162 moves to the closed position and closes the orifice opening 74 when the shake vibration is input, it is synchronized with the input vibration (shake vibration). If the opening area and opening time of the auxiliary opening 134 opened by the plunger member 162 are appropriately adjusted by periodically opening the auxiliary opening 166, the change in the hydraulic pressure in the main liquid chamber 42 can be reduced by a desired amount. Since the hydraulic pressure in the hydraulic pressure space 130 increases or decreases according to the magnitude (pressure amplitude) of the hydraulic pressure change in the main fluid chamber 42, the input vibration changes from the shake vibration to the idle vibration. In this case, the urging force of the coil spring 160 that urges the plunger member 162 toward the open position is caused to close the plunger member 162 generated by the hydraulic pressure in the hydraulic pressure space 130. It is possible to sufficiently increase the holding force to be held in the.

  Thereby, when the input vibration changes from the shake vibration to the idle vibration, the time (response time) from when the input vibration changes to the idle vibration until the plunger member 162 starts to move to the open position side is sufficiently short. Therefore, the time required until the idle orifice 124 is changed from the closed state to the open state by the plunger member 162 can be effectively shortened.

  Further, in the vibration isolator 10, 140, 150 described above, a part of the shake orifice 122 on the main liquid chamber 42 side is the common orifice part 70 that forms a part of the idle orifice 124. Since the common orifice portion 70 can form a part of the idle orifice 124, the two shake orifices 122 and the idle orifice 124 can be efficiently arranged in a narrow space in the outer cylinder fitting 12, thereby reducing the apparatus size. Can be downsized efficiently.

  Further, in the vibration isolator 10, 140, 150, the shake orifice 122 (common orifice portion 70 and dedicated orifice portion 72) and part of the idle orifice 124 (common orifice portion) are formed on the outer peripheral surface of the orifice member 46 formed in a substantially cylindrical shape. 70) and the cylinder chamber 76 (orifice space 132) is provided on the inner peripheral side of the orifice member 46, thereby suppressing an increase in the size of the orifice member 46 (partition metal fitting 36) in the axial direction and the radial direction. In addition, since the shake orifice 122 that requires a relatively long path length and the idle orifice 124 that requires a large cross-sectional area can be efficiently arranged in the partition metal fitting 36, the overall size of the apparatus can be efficiently reduced as a result. .

  In the vibration isolator 10, 140, 150 according to the present embodiment, one of the two orifices (the first restriction passage and the second restriction passage) is a shake orifice 122 corresponding to shake vibration, and the other is idle. Although the idle orifice 124 corresponding to vibration is used, 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 has a relatively low frequency. It is only necessary to correspond to the vibration in the frequency range, and the second restriction path may correspond to the vibration in the relatively high frequency range.

  Further, in the vibration isolator 10, 140, 150, the mounting bracket 20 is connected to the engine side and the outer cylinder bracket 12 is connected to the vehicle body side. Conversely, the mounting bracket 20 is connected to the vehicle body side. The outer cylinder fitting 12 may be connected to the engine side.

  Further, in the vibration isolator 10, 140, 150 according to the present embodiment, the liquid is supplied from the main liquid chamber 42 into the hydraulic pressure space 130 through the check valve 128 when the hydraulic pressure in the main liquid chamber 42 is increased. The fluid pressure in the space 130 is increased to an equilibrium pressure corresponding to the fluid pressure upper limit value of the main fluid chamber 42, and the plunger member 78 is moved from the open position by the fluid pressure (positive pressure) in the fluid pressure space 130 when a shake vibration is input. In contrast 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, the check valve is moved to the closed position. The liquid is allowed to flow out from the hydraulic pressure space 130 into the main fluid chamber 42 through this check valve, thereby reducing the hydraulic pressure in the hydraulic pressure space 130 to an equilibrium pressure corresponding to the lower limit value of the hydraulic pressure in the main fluid chamber 42. When the shake vibration is input, the fluid pressure (negative pressure) in the fluid pressure space 130 is Ri may plunger member 78 from the open position to be moved to the closed position.

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 a perspective view which shows the structure of the orifice member in the vibration isolator shown by FIG. It is a perspective view of the partition metal fitting for demonstrating the other example of the auxiliary | assistant opening 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 in this invention. It is a perspective view which shows the structure of the plunger member in the vibration isolator shown by FIG. It is a perspective view of the plunger member for demonstrating the other example of the auxiliary | assistant opening 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 3rd Embodiment in this invention.

Explanation of symbols

10 Vibration isolator 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 122 Shake orifice (first restriction passage)
124 Idle orifice (second restricted passage)
126 Hydraulic pressure release path 128 Check valve 130 Hydraulic pressure space 132 Orifice space 134 Auxiliary opening 136 Auxiliary opening 140 Antivibration device 142 Auxiliary opening 144 Auxiliary opening 150 Antivibration device 156 Check valve 160 Coil spring (biasing member)
164 Plunger opening 166 Auxiliary opening

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,
A hydraulic pressure release path for allowing the liquid in the pressurized space to flow into the orifice space or the sub liquid chamber when the plunger member returns to the open position by the biasing force of the biasing member;
An auxiliary opening that is provided so as to face the orifice space and communicates the orifice space in the second restriction passage with another portion;
When the plunger member is moved to the open position by the urging force of the urging member, the orifice opening is opened, and the blocking is performed against the urging force of the urging member by the hydraulic pressure in the hydraulic pressure space. When moved to a position, the vibration control device is configured to vibrate in the expansion / contraction direction in accordance with a change in hydraulic pressure in the main liquid chamber while closing the orifice opening, and to periodically open and close the auxiliary opening. A part of the first restriction passage on the main liquid chamber side is configured as a common orifice part that forms a part of the second restriction passage, and the first restriction passage on the sub liquid chamber side The other part is configured as a dedicated orifice,
The vibration isolator according to claim 1, wherein the auxiliary opening communicates the orifice space with the common orifice portion. While opening the orifice opening to the inner peripheral surface of the cylinder chamber,
When the plunger member is in the closed position, a part of the plunger member is overlapped with a peripheral edge portion of the orifice opening on the inner peripheral surface of the cylinder chamber along the expansion / contraction direction, and the plunger member and the cylinder chamber The width along the expansion / contraction direction of the overlap area with the inner peripheral surface of the main fluid chamber is made larger than the amplitude of the plunger member that vibrates in the expansion / contraction direction as the hydraulic pressure changes in the main liquid chamber. Item 3. The vibration isolator according to item 1 or 2.   4. The auxiliary opening according to claim 3, wherein one end of the auxiliary opening is opened in the plunger-side overlap region of the plunger member, and the other end is opened so as to face the orifice space. Anti-vibration device.   One end of the auxiliary opening is opened to the opening-side overlap on the inner peripheral surface of the cylinder chamber, and the other end is opened to face the first restriction passage. The vibration isolator according to claim 3. The first mounting member is formed in a substantially cylindrical shape, and a liquid chamber space partitioned from the outside is provided on the inner peripheral side of the first mounting member with the elastic body and the diaphragm as part of a partition wall, and the liquid In the chamber space, a partition member is provided for partitioning the liquid chamber space into the main liquid chamber in which the elastic body is part of the partition wall and the sub liquid chamber in which the diaphragm is part of the partition wall,
The part of said 2nd restriction | limiting channel | path is provided in the said partition member along the outer peripheral surface, The said cylinder chamber is provided in the inner peripheral side of the said partition member, The any one of Claim 1 thru | or 5 characterized by the above-mentioned. The vibration isolator described in the item.

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