JP2005113978A - Vibration control device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a vibration control device capable of attenuating even the vibration having a low frequency and a small amplitude without generating noise. <P>SOLUTION: A partition member 24 is arranged, while fitting in an outer cylindrical fitting 14, and a liquid chamber part over the partition member 24 is formed as a main liquid chamber 30, and a liquid chamber part under the partition member 24 is formed as an auxiliary liquid chamber 32. A membrane 25 and a gas chamber 26 opposite to the main liquid chamber 30 through the membrane are arranged in the partition member 24. A valve mechanism 46 is arranged opposite to an opening part of an idle orifice 44 through a diaphragm 28. A selector valve 64 is connected to an expanding/shrinking chamber 35 of the valve mechanism 46 and the gas chamber 26 provided on a back surface side of the membrane 25. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a vibration isolator that prevents transmission of vibration from a member that generates vibration, and is particularly applicable to a fluid-filled vibration isolator that can be applied to an engine mount, a bush, or the like of an automobile. .

  For example, an anti-vibration device as an engine mount is disposed between an engine that is a vibration generation unit of a vehicle and a vehicle body that is a vibration receiving unit, and the vibration isolation device absorbs vibration generated by the engine. It has a structure that prevents transmission to the vehicle body side. In recent years, a liquid-encapsulated vibration isolator having a high anti-vibration effect has been proposed as a type of this anti-vibration device, and the prior art will be described below using this liquid-encapsulated anti-vibration device as an example.

  For example, each of the two orifices connecting between the main liquid chamber and the two sub liquid chambers has two orifices, and the rigidity of the two diaphragms respectively forming the partition walls of the two sub liquid chambers is set to an appropriate size, A vibration isolator having a mechanism for sucking and fixing one diaphragm with a negative pressure is considered. Further, a vibration isolator having a structure in which an opening of an idle orifice can be opened and closed by a negative pressure actuator in a double orifice or single orifice configuration has been considered.

However, these anti-vibration devices have a drawback that the spring characteristics in the high frequency region in the running state are increased. And in order to improve the performance, the vibration isolator as shown in FIG.3 and FIG.4 which added the play mechanism which consists of a diaphragm was considered.
That is, in the vibration isolator shown in FIGS. 3 and 4, the main liquid chamber 112 and the sub liquid chamber 112 are connected to the orifice member 120 incorporated in the partition members 116 and 118 that partition the main liquid chamber 112 and the sub liquid chamber 114. An idle orifice 122 communicating with the liquid chamber 114 is formed. Further, the open end of the idle orifice 122 is opened and closed by a valve 124 which is a sealing valve.

  Therefore, the spring member 130 urges the valve 124 upward as shown in FIG. 3 to seal the open end of the idle orifice 122, and the air chamber 128 is set to a negative pressure as shown in FIG. As a result, the open end of the idle orifice 122 is opened.

  However, in this conventional vibration isolator, the flange portion 120A of the orifice member 120 is arranged between the partition member 116, 118 on the main liquid chamber 112 side and the diaphragm 132, and the claw fitting 126 is used for the orifice. The member 120 is connected to the valve 124. Accordingly, the claw fitting 126 moves up and down as the opening end of the idle orifice 122 opens and closes, and the flange portion 120A of the orifice member 120 connected to the valve 124 via the claw fitting 126 can vibrate the diaphragm 132. Switch between state and fixed state.

  In other words, according to the conventional structure, in the idling state where idling vibration occurs, the air chamber 128 is sucked with negative pressure and the valve 124 is lowered to open the idle orifice 122 and to connect the fitting 124 connected to the valve 124. 126 will pull down the orifice member 120. Along with this, the diaphragm 132 is sandwiched between the flange portion 120A of the orifice member 120 and the partition members 116 and 118, whereby the action of the backlash mechanism is stopped in the idle state, and the idle resonance is largely obtained.

  However, in the vibration isolator having the movable plate type diaphragm 132 as shown in FIGS. 3 and 4, since there is a gap between the diaphragm 132 and the surrounding wall surface, vibration with low frequency and small amplitude is possible. When is input, there is a drawback that the pressure is released from the gap and the vibration is not sufficiently attenuated.

On the other hand, the rubber diaphragm 132 is sandwiched between the upper and lower flange portions 120A and the partition member 118, so that the diaphragm 132 comes into contact with the upper and lower metal parts. Vibration may stop. Then, when this vibration stops, a sudden change in the spring constant occurs, the spring constant deforms nonlinearly, and the pressure of the liquid in the main liquid chamber suddenly rises and abnormal noise may occur.
An object of the present invention is to provide a vibration isolator capable of attenuating even low-frequency and small-amplitude vibrations without causing abnormal noise in consideration of the above facts.

The vibration isolator according to claim 1 includes a first attachment member coupled to one of the vibration generating unit and the vibration receiving unit;
A second attachment member coupled to the other of the vibration generating portion and the vibration receiving portion;
An elastic body arranged between these mounting members and capable of elastic deformation;
A main liquid chamber in which liquid is sealed with the elastic body as a part of the partition wall and the internal volume changes due to deformation of the elastic body;
A membrane that forms the other part of the partition wall of the main liquid chamber in an elastically deformable manner;
A gas chamber disposed opposite the main liquid chamber through the membrane;
A secondary liquid chamber in which liquid is enclosed and expandable and contractible;
A partition member for partitioning the main liquid chamber and the sub liquid chamber and providing a passage communicating between the main liquid chamber and the sub liquid chamber;
A valve mechanism that is elastically deformable and that closes the passage as the internal pressure is changed to atmospheric pressure and opens the passage as the internal pressure is reduced to a negative pressure;
A switching valve that simultaneously switches the atmospheric pressure in the gas chamber and the valve mechanism between atmospheric pressure and negative pressure, and prevents deformation of the membrane at the time of negative pressure;
It is characterized by having.

The operation of the vibration isolator according to claim 1 will be described below.
When vibration is transmitted from the vibration generating unit connected to any of the attachment members, the elastic body is elastically deformed and the vibration is attenuated by the elastic body. Along with the elastic deformation of the elastic body, the inner volume of the main liquid chamber changes, and the sub liquid chamber and the main liquid chamber are formed by a passage provided by a partition member that partitions the main liquid chamber and the sub liquid chamber. Therefore, a change in pressure occurs in the liquid in the passage, and the sub liquid chamber is eventually expanded and contracted. As a result, when vibration is transmitted from the vibration generating unit side, not only the vibration is attenuated by the deformation of the elastic body, but also the liquid column resonance of the liquid in the passage between the main liquid chamber and the sub liquid chamber, etc. Similarly, the vibration is attenuated, and the vibration is hardly transmitted to the vibration receiving portion side.

  However, in this claim, not only a part of the partition wall of the main liquid chamber is formed so that the membrane can be elastically deformed, but there is also a gas chamber arranged to face the main liquid chamber via this membrane. ing. Further, the valve mechanism is configured to open and close a passage communicating between the sub liquid chamber and the main liquid chamber, and the atmospheric pressure and the negative pressure are simultaneously controlled by the switching valve in the gas chamber and the valve mechanism. Can be switched between.

  That is, as the internal pressure in the gas chamber and the valve mechanism is switched to the atmospheric pressure by the switching valve, the membrane elastically deforms and the valve mechanism closes the passage, and the internal pressure in the gas chamber and the valve mechanism Is switched to a negative pressure by the switching valve, the deformation of the membrane is prevented and the valve mechanism opens this passage.

  Therefore, as the internal pressure is switched to the atmospheric pressure by the switching valve, this passage is closed by the valve mechanism, so that, for example, shake vibration is reduced by another passage that is always open. When vibration with a small amplitude and low frequency is input along with the input of this shake vibration, the membrane is freely elastically deformed due to the presence of air in the gas chamber at atmospheric pressure, and the pressure in the main liquid chamber is reduced. Absorb. As a result, an increase in the hydraulic pressure in the main liquid chamber is prevented, and this amplitude is small and low-frequency vibration is attenuated.

  At this time, since the back pressure of the gas chamber becomes a cushion, unlike the structure of the conventional example having the diaphragm, the spring constant of the membrane does not rise abruptly and does not become a non-linear spring constant in this claim. That is, according to this claim, unlike the conventional vibration isolator, abnormal noise due to non-linear change in the internal pressure of the main liquid chamber is less likely to occur.

  On the other hand, if the frequency of vibration from the vibration generating unit changes, and if vibration such as idle vibration, which is higher in frequency than shake vibration that cannot be reduced in other passages that are always open, is transmitted, it will be adjusted accordingly. Thus, the internal pressure of the valve mechanism is switched to a negative pressure by the switching valve to open the passage, and this idle vibration is reduced.

  At this time, not only in the valve mechanism but also in the gas chamber at the same time, negative pressure is simultaneously applied to prevent the membrane from being deformed as the passage is opened, so that the membrane is opened without being obstructed by the presence of the membrane. The liquid surely flows only into the passage, and the liquid in the passage more reliably resonates with the liquid column.

  As described above, the vibration isolator according to the present invention appropriately switches whether the membrane is elastically deformed or not with the opening and closing of the passage such as the idle orifice. Does not cause abnormal noise.

The operation of the vibration isolator according to claim 2 will be described below.
This claim also has the same configuration as that of claim 1 and has the same effect, but this claim further has a configuration in which the membrane and the gas chamber are arranged in the partition member. That is, the membrane and the gas chamber are also disposed in the partition member that partitions the main liquid chamber and the sub liquid chamber and has a passage that communicates between the main liquid chamber and the sub liquid chamber. Another member such as a metal fitting for disposing the gas chamber becomes unnecessary, and accordingly, the manufacturing cost of the vibration isolator is reduced.

The operation of the vibration isolator according to claim 3 will be described below.
This claim also has the same structure as that of claim 1 and has the same function, but in this claim, the membrane is a rubber membrane member, and the outer peripheral portion of this membrane member is vulcanized on the surrounding wall surface. It has a configuration of being bonded.

  In other words, by vulcanizing and bonding the membrane to the surrounding wall surface as a rubber membrane member, the membrane functions not only reliably but also functions as a membrane that absorbs the pressure in the main liquid chamber. The gas chamber adjacent to the membrane is sealed by the sulfur bonding, and the negative pressure can be surely generated as the air in the gas chamber is sucked, so that the internal pressure of the gas chamber can be easily controlled.

The operation of the vibration isolator according to claim 4 will be described below.
The present invention also has the same configuration as that of the first aspect and has the same function. However, in the present invention, the spring member is disposed in the valve mechanism, and the valve member moves toward the direction in which the spring member closes the passage. It has the structure of energizing. That is, when the internal pressure of the valve mechanism is set to atmospheric pressure, the valve mechanism can be pressed by the spring member around the passage provided in the partition member, and the passage can be reliably closed.

The operation of the vibration isolator according to claim 5 will be described below.
The present claim also has the same configuration as that of the fourth embodiment and exhibits the same action, but the present claim further has a configuration in which the spring member is a coil spring. That is, by adopting the coil spring as a spring member, a sufficient spring force can be obtained even with a small coil spring while enhancing the durability. For this reason, even when the valve mechanism has a compact structure, the opening and closing of the passage can be reliably switched.

The operation of the vibration isolator according to claim 6 will be described below.
This claim has the same configuration as that of claim 1 and has the same function, but the present claim further has a configuration in which a portion near the outer periphery of the valve mechanism is formed of a rubber seal material. ing. In other words, the deformation of the rubber seal material enables the valve mechanism to be elastically deformed, and the internal pressure of the valve mechanism is switched as the seal mechanism can surely seal the inside of the valve mechanism. It is possible to easily switch with a valve.

  As described above, according to the above-described configuration of the present invention, there is an excellent effect that a vibration isolator capable of attenuating even low-frequency and small-amplitude vibrations and generating no abnormal noise is obtained. As a fluid-filled vibration isolator that can be applied to bushes and the like, it exhibits particularly excellent effects.

Next, an embodiment of a vibration isolator according to the present invention is shown in FIGS. 1 and 2, and the present embodiment will be described based on these drawings.
As shown in FIGS. 1 and 2 representing the present embodiment, a bottom plate metal fitting 12 as a first attachment member is formed in a cylindrical shape having a bottom portion on the lower side of the vibration isolator 10. A tubular lower port 15 serving as an opening to the outside is attached to the bottom center of the bottom plate metal fitting 12. Further, a plurality of brackets for connecting and fixing the vibration isolator 10 to a vehicle body (not shown) are provided on the outer peripheral side of the bottom plate metal fitting 12 in the circumferential direction of the bottom plate metal fitting 12 (not shown).

  Further, an outer cylinder fitting 14 is arranged on the upper portion of the bottom plate fitting 12, and the lower end portion of the cylindrical portion 14 </ b> A formed in the cylindrical shape of the outer cylinder fitting 14 is caulked on the upper surface of the bottom plate fitting 12. Thus, the outer cylinder fitting 14 is arranged while being connected to the bottom plate fitting 12. A tubular side port 16 serving as an opening to the outside is attached to the side surface of the cylindrical portion 14 </ b> A of the outer cylinder fitting 14. In addition, the upper side of the outer cylinder fitting 14 is formed so as to expand in a tapered shape, and the lower side of the cylindrical elastic body 18 made of rubber is formed on the inner peripheral surface of the upper side of the outer cylinder fitting 14. It is vulcanized and bonded.

  An upper mounting bracket 20 formed in a plate shape as a second mounting member is located at the upper central portion of the elastic body 18, and the upper side of the elastic body 18 is vulcanized and bonded to the upper mounting bracket 20. Has been. A bolt 21 used for connecting the engine is fixed to the central portion of the upper mounting bracket 20, and an unillustrated engine side bracket is fixed to the upper mounting bracket 20 by being screwed to the bolt 21. Will be connected.

  On the other hand, a fitting fitting 22 formed in a ring shape is fitted and installed on the inner peripheral surface on the lower side of the outer cylindrical fitting 14 through a thinned portion of the elastic body 18. A diaphragm 28, which is a thin, elastically deformable rubber elastic film, is disposed on the inner side of the fitting metal fitting 22 with its outer peripheral end vulcanized and bonded to the inner peripheral surface of the fitting metal fitting 22. A space sandwiched between the elastic body 18 and the diaphragm 28 constitutes a liquid chamber in which a liquid such as ethylene glycol is enclosed.

  Furthermore, a disc-shaped partition member 24 is disposed in the liquid chamber while the outer peripheral portion thereof is fitted to the outer tube fitting 14 through the thinned portion of the elastic body 18. On the upper surface side of the partition member 24, a concave portion 24A formed in a ring shape is provided. And, in the recess 24A of the partition member 24, a membrane 25, which is a film member made of rubber and similarly formed in a ring shape, is installed in a form in which its outer peripheral portion is vulcanized and bonded to the surrounding wall surface, Further, the space on the back side in the recess 24 </ b> A is a gas chamber 26.

  As a result, the partition member 24 divides the liquid chamber so that the liquid chamber is divided into two, the liquid chamber portion on the upper side of the partition member 24 is the main liquid chamber 30, and the liquid chamber portion on the lower side of the partition member 24 is the sub chamber. The partition member 24 is provided with a membrane 25 and a gas chamber 26 facing the main liquid chamber 30 through the membrane 25. A circular groove 24B that is coaxial with the gas chamber 26 is formed at the bottom of the gas chamber 26, and the other end of the through hole 24C that is connected to the groove 24B at one end is connected to the side port 16. Yes.

  Therefore, in the present embodiment, a part of the partition wall of the main liquid chamber 30 in which the liquid is sealed is configured by the elastic body 18, and the other part of the partition wall of the main liquid chamber 30 is configured to be elastically deformable by the membrane 25. Then, a part of the partition wall of the sub liquid chamber 32 in which the liquid is sealed is constituted by the diaphragm 28.

  And in the center part of this partition member 24, it forms so that the idle orifice 44 which is a large diameter channel | path may penetrate. That is, one end of the idle orifice 44 extends upward to be opened to the main liquid chamber 30, and the other end side of the idle orifice 44 extends downward to be opened to the sub liquid chamber 32. However, this is an idle vibration absorbing passage communicating between the main liquid chamber 30 and the sub liquid chamber 32.

  On the other hand, a groove portion 40 is formed in the outer peripheral portion of the partition member 24 so as to extend along the circumferential direction, and the open end of the groove portion 40 is blocked by the thinned portion of the elastic body 18. Thus, a shake orifice 42 which is a passage for absorbing shake vibration is formed. One end side of the shake orifice 42 extends upward and is opened to the main liquid chamber 30, and the other end side of the shake orifice 42 extends downward and is opened to the sub liquid chamber 32.

  As described above, the main liquid chamber 30 and the sub liquid chamber 32 are communicated with each other via the shake orifice 42 and the idle orifice 44. Further, the idle orifice 44 of the pair of orifices 42 and 44 has a short passage passage and a large diameter, so that the liquid passage resistance is smaller than that of the shake orifice 42.

  Further, a ring-shaped support fitting 55 is sandwiched between the bottom plate fitting 12 and the outer cylinder fitting 14, and is a rubber seal material formed in a disk shape on the inner peripheral surface of the support fitting 55. The outer peripheral end of the rubber film 56 is fixed. Between the bottom plate 12 and the diaphragm 28, a valve body 50, which is a metal valve body formed in a cylindrical shape so as to close the central portion of the rubber film 56, is formed at the opening of the idle orifice 44. They are arranged so as to face each other with the diaphragm 28 interposed therebetween.

  For this reason, the portion near the outer periphery of the valve body 50 is constituted by the rubber film 56 and can be elastically deformed. When the idle orifice 44 is closed, the valve body 50 contacts the diaphragm 28 with the lower opening end of the partition member 24. By contact, the valve body 50 surely seals the idle orifice 44.

  As a result of the above, a space serving as the expansion / contraction chamber 34 is defined with the rubber film 56 and the valve body 50 as the upper surface and the bottom surface of the bottom plate 12 as the lower surface, and the space between the rubber film 56 and the diaphragm 28 is defined. For example, a through-hole (not shown) is formed in the portion of the outer cylinder fitting 14 corresponding to the air chamber 36.

  In other words, the space between the portion of the diaphragm 28 facing the sub liquid chamber 32 and the rubber film 56 is an air chamber 36 to facilitate the displacement of the diaphragm 28, and the expansion / contraction chamber is formed by the lower port 15 described above. The air in 34 can be sucked and discharged. Further, a coil spring 48 that is a spring member for urging the valve main body 50 upward is disposed between the bottom surface of the bottom plate 12 in the expansion / contraction chamber 34 and the valve main body 50. Accordingly, the valve main body 50 connected to the rubber film 56 and capable of moving up and down is always urged upward by the coil spring 48, which is the direction in which the idle orifice 44 is closed.

  Therefore, in the present embodiment, the expansion / contraction chamber 34, the rubber film 56, the coil spring 48, and the valve main body 50 form a valve mechanism 46 that is a negative pressure actuator. Therefore, as the internal pressure of the expansion / contraction chamber 34 of the valve mechanism 46 is changed to atmospheric pressure, the valve body 50 is reliably raised by the urging force of the coil spring 48 to close the idle orifice 44 and the internal pressure is negative. As the pressure is increased, the valve body 50 moves down against the biasing force of the coil spring 48 to open the idle orifice 44.

  Furthermore, one end of a pipe 61 is connected to the aforementioned lower port 15, and one end of a pipe 62 is connected to the aforementioned side port 16, and the other end of these pipes 61, 62 is connected to a switching valve 64. Each is connected. That is, the switching valve 64 is connected to the expansion / contraction chamber 34 of the valve mechanism 46 and the gas chamber 26 on the back side of the membrane 25. The switching valve 64 constitutes a three-port two-position switching valve that is an electromagnetic valve that is electromagnetically operated, and is connected to a connection pipe 66 that is connected to an intake manifold 76 that is an intake portion of the engine, as shown in FIG. At the same time, it can be opened to the atmosphere.

  As described above, the switching valve 64 communicates with the intake manifold 76 side so that the air pressure in the gas chamber 26 and the expansion / contraction chamber 34 of the valve mechanism 46 is simultaneously negative, and the switching valve 64 communicates with the atmosphere side. These can be switched between the inside and the state in which the pressure in the expansion / contraction chamber 34 is set to the atmospheric pressure at the same time. Accordingly, when the gas chamber 26 is set to a negative pressure, the membrane 25 is deformed. It has been stopped.

  On the other hand, the switching valve 64 is connected to a control circuit 70 which is a control means for judging the driving situation of the vehicle and turning on / off the applied voltage. The control circuit 70 is driven by a vehicle power source, and can detect a vehicle speed and an engine speed by receiving at least detection signals from a vehicle speed sensor 72 and an engine speed sensor 74 that determine the driving state of the vehicle.

  As a result, the control circuit 70 can determine whether shake vibration or idle vibration has occurred, that is, whether the vehicle is stopped or traveling. Therefore, the control circuit 70 controls energization to the switching valve 64 and stop of energization, and the atmospheric pressure in the gas chamber 26 and the expansion / contraction chamber 34 is switched between the atmospheric pressure and the negative pressure.

Next, the operation of the vibration isolator 10 according to the present embodiment will be described.
When the engine mounted on the upper mounting bracket 20 is operated, the vibration of the engine is transmitted to the elastic body 18 via the upper mounting bracket 20. The elastic body 18 acts as a main body of vibration absorption, and can absorb vibration by a vibration control function based on the internal friction of the elastic body 18 that is elastically deformed. Further, as the elastic body 18 is elastically deformed, the inner volume of the main liquid chamber 30 is changed, and a portion of the partition wall is formed between the sub liquid chamber 32 and the main liquid chamber 30 that are deformable by the diaphragm 28. A change in pressure occurs in the liquid in the orifices 42 and 44 that are provided in the partition member 24 that separates the sub liquid chamber 32 and communicates between the sub liquid chamber 32 and the main liquid chamber 30. The diaphragm 28 is deformed as the pressure of the liquid in the orifices 42 and 44 changes, so that the sub liquid chamber 32 is expanded and contracted.

  As a result, when the vibration from the engine side is transmitted, the vibration is not only attenuated by the deformation of the elastic body 18 but also the liquid in the orifices 42 and 44 between the main liquid chamber 30 and the sub liquid chamber 32. This vibration is also damped by the damping action based on the liquid column resonance of the flow, and the vibration is hardly transmitted to the vehicle body side.

  However, in the present embodiment, a part of the partition wall of the main liquid chamber 30 is formed so that the membrane 25 can be elastically deformed, and the gas chamber disposed opposite to the main liquid chamber 30 via the membrane 25. 26 is present. Further, the valve mechanism 46 is configured to open and close the idle orifice 44 that communicates between the sub liquid chamber 32 and the main liquid chamber 30, and the switching valve 64 allows the inside of the gas chamber 26 and the valve mechanism 46 to be opened. At the same time, the atmospheric pressure can be switched between atmospheric pressure and negative pressure. From such a structure, the present embodiment operates as follows.

Below, the specific operation | movement of the vibration isolator 10 which concerns on this Embodiment is demonstrated.
For example, when the vehicle travels, shake vibration occurs. The control circuit 70 determines that the shake vibration is generated by the vehicle speed sensor 72 and the engine speed sensor 74, and causes the switching valve 64 to communicate the gas chamber 26 and the expansion / contraction chamber 34 of the valve mechanism 46 with the atmosphere side.

  As a result, the air pressure in the gas chamber 26 and the expansion / contraction chamber 34 becomes atmospheric pressure, and the membrane 25 can be elastically deformed and the valve body 50 of the valve mechanism 46 is coil spring 48 as in the running state shown in FIG. The valve main body 50 comes into contact with the lower end of the partition member 24 through the diaphragm 28. As a result, the idle orifice 44 is closed, and the main liquid chamber 30 and the sub liquid chamber 32 are communicated with each other only by the shake orifice 42 that is always open. Shake vibration is absorbed by the liquid actively going back and forth to receive passage resistance or liquid column resonance.

  As described above, when the idle orifice 44 is closed by the valve body 50 of the valve mechanism 46, for example, shake vibration is reduced by the shake orifice 42 that has a large passage resistance and is always open. In addition, when a vibration having a small amplitude and a low frequency is input along with the input of the shake vibration, the membrane 25 is freely elastically deformed due to the presence of air in the gas chamber 26 at atmospheric pressure, and Absorbs the pressure in the liquid chamber 30. As a result, the increase of the hydraulic pressure in the main liquid chamber 30 is prevented, and the amplitude is small and the low frequency vibration is attenuated.

  At this time, since the back pressure of the gas chamber 26 becomes a cushion, unlike the structure of the conventional example having the diaphragm, the spring constant of the membrane 25 does not rise abruptly. Don't be. That is, according to the present embodiment, unlike the conventional vibration isolator, abnormal noise due to non-linear change in the internal pressure of the main liquid chamber 30 is unlikely to occur.

  On the other hand, for example, when the vehicle stops, the engine becomes idling, and idle vibration having a vibration frequency higher than the shake vibration occurs. In this case, the shake orifice 42 is clogged. At this time, the control circuit 70 determines that idle vibration is occurring by the vehicle speed sensor 72 and the engine speed sensor 74, and the switching valve 64 causes the inside of the gas chamber 26. The inside of the expansion / contraction chamber 34 of the valve mechanism 46 is communicated with the intake manifold 76 side.

  As a result, the inside of the expansion / contraction chamber 34 becomes negative pressure, and the valve main body 50 is moved away from the lower end of the partition member 24 against the coil spring 48 as shown in the idle state shown in FIG. It becomes an open state to open. For this reason, the main liquid chamber 30 and the sub liquid chamber 32 are communicated with each other via the idle orifice 44, and the liquid can go back and forth through the idle orifice 44. As a result, the liquid resonates in the idle orifice 44, the dynamic spring constant of the vibration isolator 10 is reduced, and idle vibration is absorbed.

  At this time, not only in the expansion / contraction chamber 34 of the valve mechanism 46 but also in the gas chamber 26 is simultaneously made negative, the membrane 25 is sucked into the gas chamber 26 as the idle orifice 44 is opened, and the membrane 25 Therefore, the liquid surely flows only into the opened idle orifice 44 without being obstructed by the presence of the membrane 25, and the liquid in the idle orifice 44 is more reliably subjected to liquid column resonance. Etc. That is, pressure release in the main liquid chamber 30 due to the elastic deformation of the membrane 25 does not occur, the liquid column resonance is increased, and the dynamic spring constant is greatly reduced.

  As described above, the vibration isolator 10 according to the present embodiment appropriately switches the elastic deformation of the membrane 25 as the idle orifice 44 is opened and closed, so that even a low-frequency vibration with a low frequency can be attenuated. In addition, no abnormal noise is generated.

  On the other hand, in the present embodiment, the membrane 25 and the gas chamber 26 are arranged on the partition member 24 in such a form that the outer peripheral portion of the membrane 25 made of a rubber film member is vulcanized and bonded to the surrounding wall surface. Accordingly, the membrane 25 and the gas chamber 26 are provided in the partition member 24 having the orifices 42 and 44 that partition the main liquid chamber 30 and the sub liquid chamber 32 and communicate between the main liquid chamber 30 and the sub liquid chamber 32. Also, another member such as a metal fitting for arranging the membrane 25 and the gas chamber 26 becomes unnecessary, and accordingly, the manufacturing cost of the vibration isolator 10 is reduced.

  Further, since the outer peripheral portion of the membrane 25 is vulcanized and bonded to the surrounding wall surface as a rubber film member, the function of the membrane 25 that freely elastically deforms and absorbs the pressure in the main liquid chamber 30 is surely exhibited. In addition, the gas chamber 26 adjacent to the membrane 25 is sealed by being vulcanized and bonded, and the negative pressure can be surely generated as the air in the gas chamber 26 is sucked. The internal pressure of the chamber 26 can be easily controlled.

  Furthermore, in the present embodiment, a spring member that is a coil spring 48 is disposed in the valve mechanism 46, and the coil spring 48 urges the valve mechanism 46 in a direction to close the idle orifice 44. When the internal pressure of the expansion / contraction chamber 34 of the valve mechanism 46 is set to atmospheric pressure, the valve mechanism 46 is pressed around the idle orifice 44 provided in the partition member 24 by the coil spring 48 to securely close the idle orifice 44. be able to.

  Further, by adopting the coil spring 48 as a spring member, a sufficient spring force can be obtained even with a small coil spring while enhancing the durability. For this reason, even if the valve mechanism 46 has a compact structure, the opening and closing of the idle orifice 44 can be reliably switched.

  On the other hand, in the present embodiment, the portion near the outer periphery of the valve mechanism 46 is formed by the rubber film 56 that is a rubber seal material. The rubber film 56 can be elastically deformed, and the internal pressure of the expansion / contraction chamber 34 of the valve mechanism 46 can be easily controlled by the switching valve 64 as the inside of the expansion / contraction chamber 34 of the valve mechanism 46 can be reliably sealed by the rubber film 56. It is possible to switch to

  Furthermore, in the above-described embodiment, the bottom plate metal fitting 12 is connected to the vehicle body side serving as the vibration receiving portion, and the upper mounting bracket 20 is connected to the engine side serving as the vibration generating portion. Also good. On the other hand, in the embodiment, the purpose is to prevent the vibration of the engine mounted on the automobile, but the vibration isolator of the present invention can be used for, for example, a body mount of an automobile or other uses other than the automobile. Needless to say, the shape and the like are not limited to those of the structure of the embodiment, and can be applied to a vibration isolator having another structure.

It is sectional drawing of one Embodiment of the vibration isolator which concerns on this invention, Comprising: The figure in the driving state of a vehicle is shown. It is sectional drawing of one Embodiment of the vibration isolator which concerns on this invention, Comprising: The figure in the idle state of a vehicle is shown. It is sectional drawing of the vibration isolator which concerns on a prior art, Comprising: The figure in the driving state of a vehicle is shown. It is sectional drawing of the vibration isolator which concerns on a prior art, Comprising: The figure in the idle state of a vehicle is shown.

Explanation of symbols

10 Vibration isolator 12 Bottom plate bracket (first mounting member)
18 Elastic body 20 Upper mounting bracket (second mounting member)
24 Partition member 25 Membrane 26 Gas chamber 30 Main liquid chamber 32 Sub liquid chamber 46 Valve mechanism 48 Coil spring (spring member)
56 Rubber film (sealing material)

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 arranged between these mounting members and capable of elastic deformation;
A main liquid chamber in which liquid is sealed with the elastic body as a part of the partition wall and the internal volume changes due to deformation of the elastic body;
A membrane that forms the other part of the partition wall of the main liquid chamber in an elastically deformable manner;
A gas chamber disposed opposite the main liquid chamber through the membrane;
A secondary liquid chamber in which liquid is enclosed and expandable and contractible;
A partition member for partitioning the main liquid chamber and the sub liquid chamber and providing a passage communicating between the main liquid chamber and the sub liquid chamber;
A valve mechanism that is elastically deformable and that closes the passage as the internal pressure is changed to atmospheric pressure and opens the passage as the internal pressure is reduced to a negative pressure;
A switching valve that simultaneously switches the atmospheric pressure in the gas chamber and the valve mechanism between atmospheric pressure and negative pressure, and prevents deformation of the membrane at the time of negative pressure;
An anti-vibration device comprising:   The vibration isolator according to claim 1, wherein the membrane and the gas chamber are arranged on the partition member.   2. The vibration isolator according to claim 1, wherein the membrane is a rubber membrane member, and an outer peripheral portion of the membrane member is vulcanized and bonded to a surrounding wall surface.   2. The vibration isolator according to claim 1, wherein the spring member is disposed in the valve mechanism, and the spring member biases the valve mechanism in a direction of closing the passage.   The vibration isolator according to claim 4, wherein the spring member is a coil spring. 2. The vibration isolator according to claim 1, wherein a portion near the outer periphery of the valve mechanism is formed of a rubber seal material.

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