JP2009222192A - Fluid-sealed vibration control device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a fluid-sealed vibration control device of a novel structure capable of reducing the number of part items of a relief mechanism of a pressure receiving chamber, and capable of stably exhibiting the vibration control effect based on the flowing action of fluid via an orifice passage. <P>SOLUTION: While penetratingly forming a relief hole 68 in a movable rubber film 58, an abutting plate 34 supported by a second installation member 14 is arranged on the balancing chamber 72 side of the movable rubber film 58. A blocking-up projection part 50 having a tapering-off circular inclined outer peripheral surface 52 is projectingly formed in a position corresponding to the relief hole 68 in the abutting plate 34. The relief hole 68 is blocked up by fitting the blocking-up projection part 50 in the relief hole 68 of the movable rubber film 58. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a fluid-filled vibration isolator that obtains a vibration isolation effect based on the flow action of an incompressible fluid enclosed therein, and in particular, a hydraulic pressure absorption mechanism that absorbs pressure fluctuations in a pressure receiving chamber. The present invention relates to a fluid-filled vibration isolator provided.

  Conventionally, as a kind of anti-vibration coupling body and anti-vibration support body interposed between members constituting the vibration transmission system, a fluid-filled type that obtains an anti-vibration effect based on the flow action of an incompressible fluid Anti-vibration devices are known. In this fluid-filled vibration isolator, the first mounting member and the second mounting member are connected by the main rubber elastic body, and a part of the wall portion is configured by the main rubber elastic body to enclose the incompressible fluid. The pressure receiving chamber is formed with an equilibrium chamber in which a part of the wall portion is made of a flexible membrane that is easily deformed and in which an incompressible fluid is sealed, and the pressure receiving chamber and the equilibrium chamber communicate with each other through an orifice passage. It has a damped structure. According to such a structure, a relative pressure fluctuation occurs between the pressure receiving chamber and the equilibrium chamber due to vibration input, and a vibration isolation effect based on a fluid action such as a resonance action of the fluid that flows through the orifice passage is obtained. It is done. Such a fluid-filled vibration isolator has been studied for application to, for example, an automobile engine mount, body mount, and differential mount, as well as a suspension member mount.

  Further, as an advanced type of the above-described fluid-filled vibration isolator, there is a fluid-filled vibration isolator equipped with a hydraulic pressure absorbing mechanism. In this hydraulic pressure absorbing mechanism, a movable rubber film is disposed between the pressure receiving chamber and the equilibrium chamber so that the pressure of the pressure receiving chamber is exerted on one surface of the movable rubber film and the pressure of the equilibrium chamber is exerted on the other surface. The structure is such that the pressure fluctuation in the pressure receiving chamber is absorbed by deformation of the movable rubber film due to the relative pressure difference between the pressure receiving chamber and the equilibrium chamber. As a result, for example, when a problem vibration is input in a frequency range higher than the tuning frequency of the orifice passage, the pressure fluctuation in the pressure receiving chamber is absorbed by the elastic deformation of the movable rubber film, thereby avoiding a high dynamic spring. Therefore, stabilization of the vibration isolation effect is achieved.

  By the way, in the above-described fluid-filled vibration isolator, when a large vibration load is applied between the first mounting member and the second mounting member, an excessive negative pressure is generated in the pressure receiving chamber. In some cases, air dissolved in the fluid is separated to generate bubbles called cavitation. When the water hammer pressure is generated along with the collapse of the bubbles and propagates to the first mounting member or the second mounting member, the water hammer pressure is transmitted to the vibration-proof target member such as the body of the automobile, which causes a problem. There was a risk of sound and vibration.

  In order to deal with such a problem, for example, Patent Document 1 (Japanese Patent Laid-Open No. 2007-107712) proposes a structure in which a relief mechanism is provided by using a part of an orifice passage. That is, a short-circuit channel is formed in the partition member using a part of the orifice passage, and a relief valve is provided in the opening on the pressure receiving chamber side of the short-circuit channel. At the time of shock vibration input, the relief valve is opened by the negative pressure of the pressure receiving chamber, and the pressure receiving chamber and the equilibrium chamber are short-circuited through the short-circuit channel. As a result, the pressure in the pressure receiving chamber and the pressure in the equilibrium chamber are brought into an equilibrium state, and the pressure in the pressure receiving chamber is prevented from reaching a negative pressure that generates cavitation. Is prevented.

  However, in the fluid-filled vibration isolator described in Patent Document 1, the relief valve is provided separately from the partition member, the movable rubber film, and the like, so that the number of parts is increased and the molding process and assembly of the relief valve are increased. There is a problem that the manufacturing cost such as the process increases and the manufacturing cost increases. In addition, since the short-circuit flow path is formed by using a part of the orifice passage, the degree of freedom in designing the orifice passage is limited, or a part of the wall of the orifice passage is constituted by a relief valve. There is a possibility that the fluid flow action through the orifice passage may not be stably generated.

  In order to deal with this problem, for example, as shown in Patent Document 2 (Japanese Patent Laid-Open No. 61-294236), a cut or the like is made in the movable rubber film so that the negative pressure state of the pressure receiving chamber is reduced. Thus, it is conceivable that a slit is developed based on the opening of the cut portion due to the deformation of the movable rubber film, and the pressure receiving chamber and the equilibrium chamber are short-circuited through the slit. That is, since the relief mechanism of the pressure receiving chamber is configured using elastic deformation of the movable rubber film, it is not necessary to provide a relief valve separately, and the number of parts and the manufacturing process can be reduced.

  However, in the fluid-filled vibration isolator described in Patent Document 2, when the movable rubber film is provided with a cut, an excessive positive pressure or the like that does not require opening of the cut portion is generated in the pressure receiving chamber. In addition, the movable rubber film may be elastically deformed, and the cut portion may be opened. Therefore, even when vibration is input in the tuning frequency range of the orifice passage to be vibrated, the pressure receiving chamber and the equilibrium chamber are short-circuited, making it difficult to ensure a sufficient amount of fluid flow through the orifice passage. There were inherent problems that were difficult to achieve. In addition, since the movable rubber film is repeatedly elastically deformed, the crack at the base end portion of the cut portion is extended, and the durability of the movable rubber film may become a problem.

JP 2007-107712 A JP-A 61-294236

  Here, the present invention has been made in the background as described above, and the problem to be solved is that it is possible to reduce the number of parts of the relief mechanism of the pressure receiving chamber and to reduce the number of parts through the orifice passage. An object of the present invention is to provide a fluid-filled vibration isolator having a novel structure capable of stably exhibiting a vibration isolating effect based on a fluid flow action.

  Hereinafter, the aspect of this invention made | formed in order to solve such a subject is described. In addition, the component employ | adopted in each aspect as described below is employable by arbitrary combinations as much as possible.

  The present invention provides a pressure receiving chamber in which a first mounting member and a second mounting member are connected by a main rubber elastic body, a part of a wall portion is configured by the main rubber elastic body, and an incompressible fluid is enclosed therein. Forming an equilibrium chamber in which a part of the wall is formed of a flexible membrane and enclosing an incompressible fluid, and the pressure receiving chamber and the equilibrium chamber are communicated with each other by an orifice passage, and the pressure receiving chamber and A movable rubber film is disposed between the equilibrium chambers so that the pressure of the pressure receiving chamber is applied to one surface of the movable rubber film, and the pressure of the equilibrium chamber is applied to the other surface of the movable rubber film. In the fluid-filled vibration isolator that constitutes a hydraulic pressure absorbing mechanism that absorbs minute pressure fluctuations in the pressure receiving chamber, a contact hole that is formed by penetrating a relief hole in the movable rubber film and supported by the second mounting member A plate is placed on the equilibrium chamber side of the movable rubber film and abuts In this case, a closing projection having a tapered circular inclined outer peripheral surface is formed at a position corresponding to the relief hole, and the closing projection is fitted into the relief hole of the movable rubber film so that the relief hole is formed. It is characterized by being blocked.

  In such a fluid-filled vibration isolator having a structure according to the present invention, the closing protrusion of the contact plate is fitted into the relief hole of the movable rubber film from the equilibrium chamber side. Therefore, when an excessive negative pressure is generated in the pressure receiving chamber, the movable rubber film is elastically deformed as if it is pulled toward the pressure receiving chamber, so that the closing projection protrudes from the relief hole. Thus, the pressure receiving chamber and the equilibrium chamber are communicated with each other through the relief hole of the movable rubber film. As a result, it is possible to quickly eliminate the excessive negative pressure in the pressure receiving chamber and effectively prevent the occurrence of cavitation.

  That is, in the fluid-filled vibration isolator according to the present invention, the relief mechanism that eliminates the excessive negative pressure generated in the pressure receiving chamber, the movable rubber film that constitutes the existing hydraulic pressure absorbing mechanism, and the movable rubber film It can be realized with a very simple structure by skillfully using a contact plate that restricts elastic deformation to the equilibrium chamber side.

  Therefore, in the fluid filled type vibration damping device according to the present invention, the number of parts necessary for the relief mechanism for eliminating the excessive negative pressure generated in the pressure receiving chamber can be reduced.

  In particular, in the fluid-filled vibration isolator according to the present invention, the closing protrusion protrudes toward the opening on the equilibrium chamber side of the relief hole in a state where the closing protrusion protrudes from the relief hole. Therefore, the incompressible fluid can flow into the relief hole along the tapered circular outer peripheral surface of the closing projection. Thereby, the fluid flow through the relief hole is efficiently generated. As a result, an excessive negative pressure generated in the pressure receiving chamber can be eliminated or reduced more quickly.

  On the other hand, when a positive pressure is generated in the pressure receiving chamber, the movable rubber film is pushed toward the equilibrium chamber, so that the state in which the closing projection is fitted in the relief hole is maintained. Thereby, it is possible to avoid the positive pressure in the pressure receiving chamber from escaping to the equilibrium chamber through the relief hole. As a result, when vibration that is the object of vibration isolation is input, the amount of fluid flow through the orifice passage is secured, and the vibration isolation effect based on the fluid flow action through the orifice passage is effectively and stably exhibited. Is possible.

  In the present invention, “having a tapered circular inclined outer peripheral surface” means that a cross section in a direction orthogonal to the axial direction (projection direction) is circular, and the circular cross section is from the proximal side to the distal side. This means that it has a shape that becomes smaller as it goes to, for example, a truncated cone shape, a hemispherical shape, and the like.

  And in this invention, when the protrusion for closure has such a shape, there exist the following effects (1)-(5).

  (1) The closing protrusion is easily fitted into the relief hole. As a result, the tip of the blocking projection is in contact with the opening peripheral edge of the relief hole, the blocking projection is not fitted in the relief hole, and the blocking projection bears the movable rubber film. Can be prevented from occurring.

  (2) When the closing projection is fitted into the relief hole, the relief hole and the closing projection can be positioned on the same central axis by the guide action of the tapered circular outer peripheral surface. . As a result, it is possible to stably cause the closing protrusion to be fitted into the relief hole. As a result, it is possible to stably generate the closed state of the relief hole by the closing projection.

  (3) When the positive pressure in the pressure receiving chamber acts on the movable rubber film, the closing projection can be easily pushed into the relief hole. Thereby, it becomes possible to improve the sealing accuracy of the relief hole when the relief hole is closed by the closing protrusion. As a result, it is possible to stabilize the switching operation of the relief hole communicating / blocking state, and it is possible to improve the operational reliability.

  (4) Even when the closing projection is slightly pulled out of the relief hole, a large opening (flow passage cross-sectional area) is formed between the outer peripheral surface of the closing projection and the inner peripheral surface of the relief hole. It can be expressed. Thereby, it is possible to eliminate an excessive negative pressure generated in the pressure receiving chamber as quickly as possible. As a result, it is possible to more effectively prevent cavitation.

  (5) When the closing protrusion is fitted into the relief hole, it is possible to gradually increase the contact force of the closing protrusion with the relief hole forming portion. As a result, it is possible to alleviate the occurrence of abnormal noise and impact caused by the hitting when the closing projection is fitted into the relief hole.

  Further, in the fluid filled type vibration damping device according to the present invention, the relief hole of the movable rubber film is held in a fitted state on the closing protrusion based on the elasticity of the movable rubber film, so that the relief hole is formed. It is desirable to be closed by the closing protrusion, but there is a slight gap between the inner peripheral surface of the relief hole and the outer peripheral surface of the closing protrusion in a state where no vibration is input. Also good.

  That is, even if a slight gap remains between the inner peripheral surface of the relief hole and the outer peripheral surface of the blocking projection, if a vibration is input and positive pressure is generated in the pressure receiving chamber, the movable rubber By pressing the membrane against the contact plate with the positive pressure of the pressure receiving chamber, a state in which the closing projection is fitted into the relief hole is realized, and a large amount of fluid flowing through the orifice passage is secured. Because it can.

  In the present invention, the limiting plate supported by the second mounting member is disposed on the pressure-receiving chamber side of the movable rubber film, and the limiting plate is opposed to the movable rubber film at a predetermined distance. In addition, a through-hole penetrating the limiting plate in the thickness direction is formed, and the relief hole passes through the through-hole in a contact state of the movable rubber film with the limiting plate due to the displacement of the movable rubber film toward the pressure receiving chamber side. It is desirable to be able to communicate with the pressure receiving chamber. As a result, the amount of elastic deformation of the movable rubber film toward the pressure receiving chamber can be limited by the limiting plate. As a result, the durability of the movable rubber film can be improved.

  In addition, since the relief hole can be communicated with the pressure receiving chamber through the through hole in a contact state with the restriction plate of the movable rubber film due to the displacement of the movable rubber film toward the pressure receiving chamber side, While avoiding the opening on the pressure receiving chamber side from being blocked by the limiting plate, it is possible to limit the strain around the relief hole and reduce the stress concentration.

  Further, as described above, when the restriction plate is disposed on the pressure receiving chamber side of the movable rubber film, the buffer protrusion protruding from the periphery of the relief hole toward the restriction plate and contacting the restriction plate is formed on the movable rubber film. It is desirable that they are integrally formed. Thereby, when an excessive negative pressure is generated in the pressure receiving chamber and the movable rubber film is pulled toward the pressure receiving chamber and the movable rubber film comes into contact with the restriction plate, the buffer protrusion first comes into contact with the restriction plate. Therefore, the buffering action by the buffering protrusion can be exhibited. Thereby, it is possible to reduce or prevent abnormal noise such as hitting sound when the movable rubber film comes into contact with the limiting plate.

  In this case, the buffer protrusion may not always be in contact, but it is desirable that the buffer protrusion is always in contact. As a result, it is possible to more effectively prevent abnormal sounds such as hit sounds.

  Furthermore, as described above, when the restriction plate is disposed on the pressure receiving chamber side of the movable rubber film, the movable rubber film has an outer surface shape of the closing projection at a position corresponding to the closing projection of the contact plate. A fitting recess having an inner surface shape corresponding to is formed in the equilibrium chamber side, and a relief hole is formed by an opening hole formed in the wall portion located on the pressure receiving chamber side in the fitting recess and the fitting recess. Is preferably formed. This makes it possible to stabilize the closed state of the relief hole by the closing projection.

  Further, as described above, when the restriction plate is disposed on the pressure receiving chamber side of the movable rubber film, an opposing recess that opens toward the movable rubber film is formed in the restriction plate at a position corresponding to the relief hole. It is desirable. As a result, when the movable rubber film enters the opposing recess and deforms, the amount of elastic deformation around the relief hole of the movable rubber film is limited by contact with the peripheral wall portion of the opposing recess. As a result, the stress can be relaxed, and the durability of the movable rubber film can be improved.

  In addition, when the opposing recess is formed in the limiting plate, it is desirable that the movable rubber film has a protrusion having an outer surface shape substantially corresponding to the inner surface shape of the opposing recess in the movable rubber film. As a result, when the movable rubber film comes into contact with the restricting plate, forcible deformation such that the relief hole is pushed and expanded is restricted, and further stress relaxation can be achieved. As a result, it is possible to further improve the durability of the movable rubber film.

  Hereinafter, in order to clarify the present invention more specifically, embodiments of the present invention will be described in detail with reference to the drawings.

  FIG. 1 shows an automotive engine mount 10 as an embodiment of a fluid filled type vibration damping device according to the present invention. The engine mount 10 has a structure in which a first mounting bracket 12 as a first mounting member and a second mounting bracket 14 as a second mounting member are connected by a main rubber elastic body 16. The first mounting bracket 12 is attached to the power unit of the automobile that is one member constituting the vibration transmission system, and the second mounting bracket 14 is attached to the body of the automobile that is the other member constituting the vibration transmission system. By being attached, the power unit is connected to the vehicle body in a vibration-proof manner. In the following description, the vertical direction is the axial direction of the engine mount 10 and the vertical direction in FIG. 1, which is the main vibration input direction. FIG. 1 shows a state before the engine mount 10 is mounted on the vehicle. When the engine mount 10 is mounted on the vehicle, the shared support load of the power unit is exerted in the axial direction of the engine mount 10.

  More specifically, the first mounting member 12 is made of iron, aluminum alloy, or the like, and has a substantially circular block shape. The first mounting bracket 12 is integrally formed with a mounting bolt 18 that protrudes upward. Then, the first mounting bracket 12 is attached to the power unit by screwing the attachment bolt 18 to an attachment member (not shown) on the power unit side.

  The second mounting bracket 14 is made of the same material as the first mounting bracket 12 and has a thin-walled large-diameter cylindrical shape as a whole. And the 2nd attachment metal fitting 14 is attached to a vehicle body via the bracket metal fitting (not shown) etc. which are externally fitted and fixed, for example.

  The first mounting bracket 12 and the second mounting bracket 14 structured as described above are positioned on the same central axis line with the first mounting bracket 12 being spaced apart above the second mounting bracket 14. It has been. A main rubber elastic body 16 is interposed between the first mounting bracket 12 and the second mounting bracket 14.

  The main rubber elastic body 16 has a substantially frustoconical shape, and a large-diameter recess 20 having a generally inverted mortar shape that opens downward is formed on the large-diameter end face thereof. The first mounting bracket 12 is inserted from above into the small diameter side end of the main rubber elastic body 16 and vulcanized and bonded to the outer peripheral surface of the large diameter side end of the main rubber elastic body 16. On the other hand, the inner peripheral surface of the second mounting bracket 14 is vulcanized and bonded, whereby the first mounting bracket 12 and the second mounting bracket 14 are elastically connected by the main rubber elastic body 16. That is, in this embodiment, the main rubber elastic body 16 is formed as an integral vulcanization molded product including the first mounting bracket 12 and the second mounting bracket 14.

  A seal rubber 22 is integrally formed with the main rubber elastic body 16. The seal rubber 22 is formed so as to extend downward from the lower end of the main rubber elastic body 16 and has a thick cylindrical shape as a whole. The seal rubber 22 is vulcanized and bonded to the inner peripheral surface of the second mounting bracket 14.

  The seal rubber 22 has a larger inner diameter than the lower end portion of the main rubber elastic body 16. Thereby, an annular step surface that is continuous in the circumferential direction is formed at the boundary between the main rubber elastic body 16 and the seal rubber 22. Further, in the present embodiment, the sealing rubber 22 has an annular step surface formed on the inner peripheral surface of the axially intermediate portion, and the portion above the step surface is compared to the portion below the step surface. And it is said to be thick.

  In addition, a diaphragm 24 as a flexible film is disposed at the lower end of the second mounting bracket 14. The diaphragm 24 is formed of a thin rubber film that can be easily deformed, and has a dome shape as a whole. A large-diameter cylindrical fixing ring 26 is vulcanized and bonded to the outer peripheral edge of the diaphragm 24. That is, the diaphragm 24 is formed as an integrally vulcanized molded product provided with a fixing ring 26.

  Then, the fixing ring 26 is fitted into the other opening in the axial direction of the second mounting bracket 14, and the second mounting bracket 14 is subjected to diameter reduction processing such as an eight-way drawing, whereby the fixing ring 26. Is fitted and fixed to the second mounting bracket 14 via a seal rubber 22. In the present embodiment, the lower end portion of the second mounting bracket 14 is bent toward the inner peripheral side, so that the lower end portion of the second mounting bracket 14 is brought into contact with the lower end surface of the fixing ring 26. . Thereby, the fixing ring 26 is prevented from coming off from the second mounting bracket 14.

  As described above, the fixing ring 26 is fitted and fixed to the second mounting bracket 14, so that the opening in the axially lower side of the second mounting bracket 14 is fluid-tightly covered with the diaphragm 24. As a result, a fluid chamber 28 is formed between the opposing surfaces of the main rubber elastic body 16 and the diaphragm 24 inside the second mounting bracket 14 so as to be separated from the external space and filled with an incompressible fluid. As the incompressible fluid sealed in the fluid chamber 28, for example, water, alkylene glycol, polyalkylene glycol, silicone oil, a mixed solution thereof, or the like is preferably used. In order to effectively obtain an anti-vibration effect based on the resonance action of the fluid described later, a low-viscosity fluid having a viscosity of 0.1 Pa · s or less is desirable.

  A partition member 30 is accommodated in the fluid chamber 28. The partition member 30 of the present embodiment includes an upper partition metal 32 as a limiting plate and a lower partition metal 34 as a contact plate.

  The upper partition 32 is made of a metal material such as an aluminum alloy, a hard synthetic resin material, or the like, and has a disk block shape as a whole. In addition, a central recess 36 that opens upward is formed in a radially intermediate portion of the upper partition metal fitting 32.

  Further, upper communication windows 38 and 38 are formed on the bottom wall of the central recess 36 of the upper partition 32. Although not clearly shown in the drawings, in the present embodiment, when the upper partition 32 is viewed from the axial direction, the upper communication windows 38 and 38 having a substantially semicircular shape are opposed to each other at a predetermined distance in the radial direction. Two are formed.

  Furthermore, an opposing recess 40 that opens downward is formed in the center of the bottom wall of the central recess 36 of the upper partition metal fitting 32. Therefore, in this embodiment, the opposing recess 40 is formed so as to open with a circular cross section. In the present embodiment, the inner peripheral surface of the opposing recess 40 is an inclined surface that gradually decreases in diameter toward the upper bottom side of the opposing recess 40. Further, a through hole 42 is formed in the center portion of the upper bottom of the opposing recess 40.

  Further, an upper peripheral groove 44 is formed in the outer peripheral edge portion of the upper partition metal fitting 32. The upper circumferential groove 44 is a concave groove that is opened on the outer circumferential surface of the upper partition member 32 and extends in the circumferential direction by a predetermined length. Incidentally, in the present embodiment, the upper circumferential groove 44 extends with a length of slightly less than one round in the circumferential direction.

  On the other hand, similarly to the upper partition metal fitting 32, the lower partition metal fitting 34 is formed of a metal material such as an aluminum alloy, a hard synthetic resin material, or the like, and has a circular block shape as a whole. In addition, an accommodation recess 46 that opens upward is formed in a central portion in the radial direction of the lower partition member 34.

  In addition, lower communication windows 48 are formed on the bottom wall of the housing recess 46 of the lower partition fitting 34. Although not clearly shown in the drawings, in the present embodiment, when the lower partition metal fitting 34 is viewed from the axial direction, the lower communication windows 48 and 48 having a substantially semicircular shape are opposed to each other with a predetermined distance in the radial direction. Two are formed so as to be positioned.

  Further, a closing projection 50 that protrudes upward is formed at the center of the bottom wall of the housing recess 46 of the lower partition metal fitting 34. In this case, the closing projection 50 has a circular cross section in the direction perpendicular to the axis, and has a tapered shape in which the circular cross section gradually decreases from the base end side to the protruding end side. In particular, in the present embodiment, the closing projection 50 has a circular cross section in the direction perpendicular to the axis that becomes smaller at a substantially constant rate from the proximal end side to the protruding end side, and has a truncated cone shape as a whole. That is, the outer peripheral surface of the closing projection 50 is a tapered inclined outer peripheral surface 52 that is gradually reduced in diameter as it goes from the base end side to the projecting end side.

  Furthermore, a lower notch 54 is formed at the outer peripheral edge of the lower partition fitting 34. The lower notch 54 opens on the outer peripheral surface and the upper surface of the lower partition metal fitting 34 and extends in a circumferential direction by a predetermined length. Incidentally, in the present embodiment, the lower notch 54 extends in the circumferential direction with a length of slightly less than one round.

  The upper partition metal fitting 32 and the lower partition metal fitting 34 having the above-described structure are superposed vertically on the same central axis. The upper partition 32 and the lower partition 34 are positioned with respect to each other in the circumferential direction, and the upper communication windows 38 and 38 and the lower communication windows 48 and 48 overlap with each other in the axial projection. The end of the upper circumferential groove 44 and the end of the lower notch 54 overlap each other in the axial projection.

  Further, by combining the upper partition metal fitting 32 and the lower partition metal fitting 34 together, the upper surface opening of the lower notch 54 formed in the lower partition metal fitting 34 is covered with the outer peripheral edge of the upper partition metal fitting 32. The lower notch 54 has a groove shape that opens to the outer peripheral side. Furthermore, a connection path (not shown) is formed on the lower surface of the upper circumferential groove 44 at one end in the circumferential direction of the upper circumferential groove 44 and the lower notch 54 aligned with each other. As a result, the upper circumferential groove 44 and the lower notch 54 are communicated in series, and a circumferential groove is formed that spirally extends in the circumferential direction with a length of less than two rounds.

  Further, by combining the upper partition metal fitting 32 and the lower partition metal fitting 34, a central recess 36 provided in the upper partition metal fitting 32, a through hole 42 formed in the bottom wall of the central recess 36, and a lower partition The closing projection 50 provided on the metal fitting 34 is positioned on the same central axis.

  Furthermore, by combining the upper partition metal fitting 32 and the lower partition metal fitting 34, the opening of the accommodation recess 46 formed in the central portion of the lower partition metal fitting 34 is the central recess 36 formed in the upper partition metal fitting 32. The housing space 56 is formed between the upper partition metal fitting 32 and the lower partition metal fitting 34. A movable rubber film 58 is disposed in the accommodation space 56.

  The movable rubber film 58 is formed of a conventionally known rubber material and has a disk shape as a whole, and has a structure in which a ring-shaped support portion 60 is integrally formed on the outer peripheral edge thereof.

  Therefore, in the present embodiment, a contact protrusion 62 as a hollow protrusion protruding upward is formed at the center of the movable rubber film 58. In particular, in this embodiment, the contact protrusion 62 has a truncated cone shape.

  The contact protrusion 62 is formed with a fitting recess 64 that opens to the lower surface. Therefore, in the present embodiment, the inner surface shape of the fitting recess 64 corresponds to the outer surface shape of the closing projection 50 provided in the lower partition fitting 34. Thereby, the inner surface of the insertion recess 64 has a cylindrical inclined inner peripheral surface that gradually decreases in diameter toward the upper bottom side, and a circular upper bottom surface.

  Further, an opening hole 66 is formed in the center of the upper base of the contact protrusion 62 so as to penetrate the contact protrusion 62 with a substantially constant cross-sectional shape in the thickness direction. Therefore, in the present embodiment, the opening hole 66 is formed to extend straight with a circular cross section. In particular, in the present embodiment, the inner diameter dimension of the opening hole 66 is smaller than the inner diameter dimension of the through hole 42 formed in the upper partition member 32. Thereby, the opening area of the opening hole 66 is made smaller than the opening area of the through hole 42.

  Then, as described above, the insertion recess 64 and the opening hole 66 are formed in the contact protrusion 62 of the movable rubber film 58, so that the movable rubber film 58 has a circle formed in the middle portion in the axial direction. A relief hole 68 is formed, the upper side of which extends straight with a substantially constant circular cross section across the annular step surface, while the diameter of the lower side increases downward as the step surface is sandwiched.

  The movable rubber film 58 having such a structure is housed in the housing recess 46 of the lower partition metal fitting 34, and the upper partition metal fitting 32 is superimposed on the lower partition metal fitting 34, so that the movable rubber film 58 is provided on the outer peripheral edge. The support portion 60 thus held is clamped and held by the bottom surface of the housing recess 46 of the lower partition metal fitting 34 and the lower surface of the upper partition metal fitting 32. Thus, in the state where the bottom wall of the central recess 36 of the upper partition metal fitting 32 and the movable rubber film 58 are opposed to each other with a predetermined distance in the axial direction, particularly in the present embodiment, the contact protrusion 62 The housing space 56 is partitioned by the movable rubber film 58 in a state where a gap is also formed between the front end surface and the upper bottom surface of the opposing recess 40 of the upper partition metal fitting 32. As a result, the accommodation space 56 is divided into two fluid-divided vertically by the movable rubber film 58.

  Further, in the state in which the movable rubber film 58 is disposed in this way, the blocking provided in the lower partition metal fitting 34 with respect to the fitting recess 64 formed in the contact protrusion 62 of the movable rubber film 58. The projecting portion 50 is fitted. In other words, the closing projection 50 provided in the lower partition metal fitting 34 is fitted into the relief hole 68 formed in the movable rubber film 58. Thus, the central recess 36 and the through hole 42 provided in the upper partition metal fitting 32, the relief hole 68 and the contact protrusion 62 formed in the movable rubber film 58, and the lower partition metal fitting 34 are provided. The closing protrusion 50 is positioned on the same central axis.

  Therefore, in this embodiment, the inclined outer peripheral surface 52 of the closing projection 50 provided on the lower partition metal fitting 34 is in contact with the elasticity of the contact projection 62 provided on the movable rubber film 58. The protrusion 62 is in close contact with the inclined inner peripheral surface of the insertion recess 64 formed in the protrusion 62. As a result, the relief hole 68 of the movable rubber film 58 is closed by the closing protrusion 50.

  The partition member 30 having such a structure can be inserted into the second mounting bracket 14 before the diaphragm 24 is assembled from the opening portion below the axial direction. A diaphragm 24 can be inserted into the second mounting member 14 in which the member 30 is inserted from an opening in the axially lower side. In this state, the upper partition member 32 is positioned on the main rubber elastic body 16 side, while the lower partition member 34 is positioned on the diaphragm 24 side. Then, the second mounting bracket 14 is subjected to diameter reduction processing such as eight-way drawing, so that the partition member 30 (the upper partition bracket 32 and the lower partition bracket 34) and the diaphragm 24 are replaced with the second mounting bracket 14. Is supported by.

  In the mounting state of the partition member 30 to the second mounting bracket 14, the outer peripheral surface of the partition member 30 is brought into close contact with the second mounting bracket 14 via the seal rubber 22. Thereby, the fluid chamber 28 is partitioned up and down across the partition member 30. As a result, a pressure receiving chamber 70 in which a part of the wall portion is configured by the main rubber elastic body 16 and incompressible fluid is formed is formed on one side across the partition member 30. On the other side across 30, an equilibrium chamber 72 is formed in which a part of the wall portion is constituted by the diaphragm 24 and in which an incompressible fluid is enclosed. In other words, the upper partition fitting 32 is positioned on the pressure receiving chamber 70 side, while the lower partition fitting 34 is positioned on the equilibrium chamber 72 side. The pressure receiving chamber 70 is configured such that a part of the wall portion is composed of the main rubber elastic body 16 so that pressure fluctuation is generated based on elastic deformation of the main rubber elastic body 16 at the time of vibration input. The equilibrium chamber 72 is configured such that a volume change can be easily allowed because a part of the wall portion is constituted by the diaphragm 24.

  The peripheral groove formed in the outer peripheral edge of the partition member 30 is closed at the outer peripheral side with the second mounting member 14 via the seal rubber 22. Thereby, a tunnel-shaped passage extending along the outer peripheral surface of the partition member 30 is formed. One end in the circumferential direction of the tunnel-shaped passage is connected to the pressure receiving chamber 70 through the communication hole 74, and the other end in the circumferential direction is connected to the equilibrium chamber 72 through the communication hole 76. As a result, an orifice passage 78 is formed which extends in a spiral shape at the outer peripheral edge of the partition member 30 and communicates the pressure receiving chamber 70 and the equilibrium chamber 72 with each other.

  In the present embodiment, the orifice passage 78 is tuned so that the vibration-proofing effect based on the fluid flow action is exhibited against vibrations around 10 Hz corresponding to the engine shake of an automobile.

  Further, the accommodation space 56 formed in the central portion of the partition member 30 is connected to the pressure receiving chamber 70 through the upper communication windows 38 and 38 formed in the upper partition member 32, while being formed in the lower partition member 34. The lower communication windows 48 and 48 are connected to the equilibrium chamber 72. As a result, the pressure of the pressure receiving chamber 70 is exerted on the upper surface of the movable rubber film 58, while the pressure of the equilibrium chamber 72 is exerted on the lower surface of the movable rubber film 58. As a result, based on the relative pressure difference between the pressure receiving chamber 70 and the equilibrium chamber 72, the radial intermediate portion of the movable rubber film 58 is elastically deformed, so that the pressure fluctuation in the pressure receiving chamber 70 can be absorbed. Yes. That is, the hydraulic pressure absorbing mechanism is configured to include the upper communication windows 38, 38 formed in the upper partition metal fitting 32, the movable rubber film 58, and the lower communication windows 48, 48 formed in the lower partition metal fitting 34. It is.

  In the present embodiment, the prevention of the vibration based on the hydraulic pressure absorption effect of the pressure receiving chamber 70 due to the elastic deformation of the movable rubber film 58 against the vibration in the middle frequency range of about 20 to 40 Hz corresponding to idling vibration, low-speed booming sound, and the like. The natural frequency of the movable rubber film 58 is tuned so that the vibration effect (vibration insulation effect based on the low dynamic spring characteristic) is effectively exhibited.

  In the engine mount 10 having the above-described structure, a relatively large pressure fluctuation is generated in the pressure receiving chamber 70 when vibrations in a low frequency region such as an engine shake which is a problem during traveling are input. Since the pressure generated in the pressure receiving chamber 70 at the time of vibration input in the low frequency range is large, the movable rubber film 58 tuned so as to exhibit an anti-vibration effect against minute amplitude vibration substantially reduces the pressure in the pressure receiving chamber 70. Cannot be absorbed. Further, in a state where no negative pressure that causes a problem is generated in the pressure receiving chamber 70, the state in which the closing projection 50 of the lower partition metal fitting 34 is fitted in the relief hole 68 of the movable rubber film 58 is maintained.

  Accordingly, absorption of pressure fluctuation in the pressure receiving chamber 70 due to elastic deformation of the movable rubber film 58 and pressure leakage through the relief hole 68 are suppressed. As a result, an effective pressure difference is generated between the pressure receiving chamber 70 and the equilibrium chamber 72, and a sufficient amount of fluid flows through the orifice passage 78 is ensured. As a result, an anti-vibration effect based on a fluid action such as a resonance action of the fluid that is caused to flow through the orifice passage 78 is effectively exhibited against vibrations in a low frequency range such as an engine shake.

  In addition, when a mid-frequency vibration such as idling vibration, which is a problem when the vehicle is stopped, or low-speed booming noise, which is a problem when traveling, is input, a pressure fluctuation with a small amplitude is generated in the pressure receiving chamber 70. In this case, since the frequency range of the input vibration is higher than the tuning frequency of the orifice passage 78, the orifice passage 78 is substantially closed due to an increase in flow resistance due to an anti-resonant action. In view of this, the pressure fluctuation in the pressure receiving chamber 70 is absorbed based on the elastic deformation of the movable rubber film 58 tuned to the middle frequency range, so that a significantly high dynamic spring due to the substantial blockage of the orifice passage 78 is achieved. Can be avoided. As a result, a good anti-vibration effect (vibration insulation effect based on low dynamic spring characteristics) against vibration in the middle frequency range is exhibited.

  When the pressure fluctuation of the pressure receiving chamber 70 is absorbed by the elastic deformation of the movable rubber film 58, the pressure generated in the pressure receiving chamber 70 is extremely small, so that the closing projection 50 is movable rubber. A negative pressure large enough to escape from the relief hole 68 of the membrane 58 is difficult to be generated in the pressure receiving chamber 70. As a result, the state in which the closing projection 50 is fitted in the relief hole 68 of the movable rubber film 58 is maintained, and the target hydraulic pressure is determined based on the displacement caused by the deformation of the radially intermediate portion of the movable rubber film 58. Absorption effect can be obtained stably.

  By the way, if a shocking heavy load is input to the engine mount 10 due to overcoming a step during driving of the automobile, an excessive negative pressure may be generated in the pressure receiving chamber 70. When the pressure in the pressure receiving chamber 70 is significantly reduced in this manner, the movable rubber film 58 is sucked toward the pressure receiving chamber 70 due to the relative pressure difference between the pressure receiving chamber 70 and the equilibrium chamber 72. 2, the movable rubber film 58 is elastically deformed and pulled toward the pressure receiving chamber 70 as shown in FIG. The periphery of the opening hole 66 is brought into contact with the periphery of the through hole 42 in the upper bottom surface of the opposing recess 40. As a result, the closing projection 50 provided on the lower partition fitting 34 located on the equilibrium chamber 72 side of the movable rubber film 58 comes out of the fitting recess 64 opened on the equilibrium chamber 72 side. . In other words, the closing projection 50 comes out of the relief hole 68. As a result, the pressure receiving chamber 70 and the equilibrium chamber 72 are communicated with each other through the through hole 42, the relief hole 68, and the lower communication windows 48 and 48, and the fluid flow of the incompressible fluid from the equilibrium chamber 72 to the pressure receiving chamber 70 is performed. The lower communication windows 48, 48, the relief hole 68, and the through hole 42 cause the excessive negative pressure in the pressure receiving chamber 70 to be eliminated or reduced as quickly as possible. .

  Therefore, in the engine mount 10 having the above-described structure, the movable rubber film 58 that absorbs minute pressure fluctuations generated in the pressure receiving chamber 70 when the vibration in the frequency range higher than the tuning frequency range of the orifice passage 78 is input. By skillfully utilizing this, it is possible to eliminate the excessive negative pressure generated in the pressure receiving chamber 70. Therefore, there are few relief mechanisms for eliminating the excessive negative pressure generated in the pressure receiving chamber 70. It can be realized with a score.

  Therefore, in the engine mount 10 having the above-described structure, the closing projection 50 is formed to protrude toward the opening of the relief hole 68 on the equilibrium chamber 72 side. The inclined outer peripheral surface 52 facilitates the flow of the incompressible fluid into the relief hole 68. As a result, the excessive negative pressure in the pressure receiving chamber 70 can be eliminated more quickly.

  Further, in the present embodiment, the blocking protrusion 50 has a truncated cone shape and has an inclined outer peripheral surface 52 which is a tapered tapered cylindrical outer peripheral surface. Therefore, an excessive negative pressure in the pressure receiving chamber 70 is obtained. It becomes possible to easily fit into the relief hole 68 after the above has been eliminated.

  Further, in the present embodiment, since the closing projection 50 has a truncated cone shape, the closing projection 50 is fitted into the relief hole 68 after the excessive negative pressure in the pressure receiving chamber 70 is eliminated. At the time of clogging, it becomes possible to easily align the centers of the closing projection 50 and the relief hole 68. As a result, it is possible to stably cause the closing protrusion 50 to be fitted into the relief hole 68.

  Furthermore, in this embodiment, since the blocking projection 50 has a truncated cone shape, when a positive pressure is generated in the pressure receiving chamber 70, the blocking projection 50 is fitted into the relief hole 68. It will be pushed in the jamming direction. As a result, the sealing accuracy when the relief hole 68 is closed can be improved. As a result, it is possible to stabilize the closed state of the relief hole 68 by the closing projection 50, and to improve the reliability of the closure of the relief hole 68 by the closing projection 50.

  Therefore, in the present embodiment, the relief hole 68 is configured to include the fitting recess 64 having an inner peripheral surface having a shape corresponding to the inclined outer peripheral surface 52 of the closing projection 50, so that It becomes possible to further improve the sealing accuracy when the protrusion 50 is fitted in the relief hole 68.

  In particular, in the present embodiment, since the inner peripheral surface of the fitting recess 64 is brought into close contact with the inclined outer peripheral surface 52 of the closing projection 50 by the elasticity of the movable rubber film 58, the closing projection 50 is relief. It becomes possible to further improve the sealing accuracy when fitted in the hole 68.

  Further, in this embodiment, when an excessive negative pressure is generated in the pressure receiving chamber 70 and the movable rubber film 58 is elastically deformed so as to be pulled toward the pressure receiving chamber 70, the movable rubber film 58 is applied to the upper partition member 32. Since the contact is made, the amount of elastic deformation of the movable rubber film 58 toward the pressure receiving chamber 70 is limited. Thereby, the distortion around the relief hole 68 in the movable rubber film 58 is limited, and the stress concentration around the relief hole 68 in the movable rubber film 58 is reduced.

  In particular, in this embodiment, since the movable rubber film 58 comes into contact with the upper partition 32 at the contact protrusion 62, the amount of elastic deformation of the movable rubber film 58 toward the pressure receiving chamber 70 is further limited. It becomes possible.

  Furthermore, in the present embodiment, since the opening area of the through hole 42 formed in the upper partition 32 is larger than the opening area of the opening hole 66 formed in the movable rubber film 58, the movable rubber film 58. Even when it is in contact with the upper partition metal fitting 32 in a state of being biased in the direction perpendicular to the axis, the opening of the opening hole 66 is blocked by the upper partition metal fitting 32, and the opening area of the opening hole 66 is reduced. This can be avoided.

  In addition, it is clear from the graph of the measurement result shown in FIG. 3 that the effect of eliminating the negative pressure in the pressure receiving chamber 70 is exhibited in the engine mount 10 of the present embodiment.

  That is, in the measurement result of the comparative example that does not have a structure for releasing the hydraulic pressure in the pressure receiving chamber 70, a significantly large negative pressure may be generated in the pressure receiving chamber 70 as indicated by a broken line in FIG. And in the state which a remarkable negative pressure generate | occur | produced, the noise and vibration generate | occur | produce by the bubble understood as the cavitation which generate | occur | produced from the liquid. Thus, in the comparative example, there is a possibility that the generation of abnormal noise or vibration due to cavitation becomes a problem.

  On the other hand, in the measurement result of the example using the engine mount 10 of the present embodiment, the negative pressure in the pressure receiving chamber 70 is effectively eliminated as shown by the solid line in FIG. The internal pressure is not close to 0, that is, a state where a significantly large negative pressure is not generated. Therefore, in the embodiment, the generation of bubbles from the liquid due to the change in the internal pressure of the pressure receiving chamber 70 is suppressed, and abnormal noise due to cavitation is reduced or avoided.

  Next, an automotive engine mount 80 according to a second embodiment of the fluid-filled vibration isolator of the present invention will be described with reference to FIG. In the second embodiment, and in the third embodiment and the fourth embodiment to be described later, the members and parts having the same structure as those of the first embodiment are shown in the drawing. The detailed description is abbreviate | omitted by attaching | subjecting the code | symbol same as a form.

  The engine mount 80 of this embodiment differs from the engine mount (10) of the first embodiment in the shape of the closing projection 82, and accordingly, the inner shape of the fitting recess 84 is also different. Is different.

  More specifically, in the present embodiment, the closing projection 82 has a hemispherical shape as a whole. In other words, the closing projection 82 of this embodiment includes a hemispherical curved inclined outer peripheral surface 86. Further, the inner surface of the fitting recess 84 has a hemispherical shape corresponding to the outer surface of the closing projection 82.

  Also in the engine mount 80 having such a structure, since the closing projection 82 includes the tapered circular inclined outer peripheral surface 86, the same effect as in the first embodiment can be obtained.

  Therefore, in this embodiment, since the blocking projection 82 has the curved outer peripheral surface 86, the incompressible fluid flows into the relief hole 68 along the outer peripheral surface of the blocking projection 82. It becomes possible to make it easy to flow. As a result, the fluid flow through the relief hole 68 can be generated more rapidly.

  Next, an engine mount 88 as a third embodiment of the fluid filled type vibration damping device according to the present invention will be described with reference to FIG.

  Compared with the engine mount (10) of the first embodiment, the engine mount 88 of the present embodiment is a loose projection that protrudes from the periphery of the relief hole 68 toward the upper partition metal fitting 32 at the tip of the contact protrusion 62. The collision part 90 is integrally formed.

  When an excessive negative pressure is generated in the pressure receiving chamber 70 and the movable rubber film 58 is elastically deformed so as to be pulled toward the pressure receiving chamber 70, the pressure receiving chamber 70 is provided on the contact protrusion 62 of the movable rubber film 58. The movable rubber film 58 comes into contact with the upper partition metal fitting 32 through the buffer protrusion 90 formed.

  Therefore, in the engine mount 88 of the present embodiment, it is possible to reduce or prevent the hitting sound when the movable rubber film 58 comes into contact with the upper partition member 32.

  Next, an automotive engine mount 92 as a fourth embodiment of the fluid filled type vibration damping device according to the present invention will be described with reference to FIG.

  Compared to the engine mount (10) of the first embodiment, the engine mount 92 of the present embodiment does not have the contact protrusion (62) formed at the central portion of the movable rubber film 58, but instead. In the central portion of the movable rubber film 58, a relief hole 94 penetrating with a substantially constant circular cross section is formed. The closing projection 50 fitted in the relief hole 94 closes the relief hole 94 by the lower corner of the relief hole 94 coming into contact with the inclined outer peripheral surface 52 in close contact. It is like that.

  Also in the engine mount 92 having such a structure, since the closing projection 50 having the tapered circular outer peripheral surface 52 is fitted into the relief hole 94, the same as in the first embodiment. Effects can be obtained.

  In the present embodiment, the closing projection 50 has the inclined outer peripheral surface 52 having a tapered cylindrical shape, while the relief hole 94 extends straight and has a circular cross section. Is slightly removed from the relief hole 94, a large opening is formed between the inclined outer peripheral surface 52 of the closing projection 50 and the cylindrical inner peripheral surface of the relief hole 94. A large amount of fluid flow through the hole 94 can be secured. As a result, the excessive negative pressure generated in the pressure receiving chamber 70 can be eliminated or reduced more quickly.

  As mentioned above, although several embodiment of this invention has been explained in full detail, these are illustrations to the last, Comprising: This invention is not limited at all by the specific description in this embodiment. .

  For example, a plurality of orifice passages may be provided. Specifically, a first orifice passage and a second orifice passage tuned to a higher frequency range than the first orifice passage may be provided.

  In addition, in the first to fourth embodiments, specific examples of applying the present invention to an engine mount for automobiles have been described. However, the present invention is applicable to body mounts, differential mounts, suspension member mounts, etc. for automobiles. Of course, the present invention can also be applied to vibration isolators for various vibrating bodies other than automobiles.

  In addition, although not listed one by one, the present invention can be carried out in a mode to which various changes, modifications, improvements and the like are added based on the knowledge of those skilled in the art. It goes without saying that all are included in the scope of the present invention without departing from the spirit of the present invention.

The longitudinal cross-sectional view which shows the engine mount as 1st embodiment of this invention. The longitudinal cross-sectional view which shows the state by which the movable rubber film of the engine mount was pulled to the pressure receiving chamber side. The graph which shows the negative pressure elimination effect of the engine mount. The longitudinal cross-sectional view which shows the engine mount as 2nd embodiment of this invention. The longitudinal cross-sectional view which shows the engine mount as 3rd embodiment of this invention. The longitudinal cross-sectional view which shows the engine mount as 4th embodiment of this invention.

Explanation of symbols

10: engine mount, 12: first mounting bracket, 14: second mounting bracket, 16: rubber elastic body, 24: diaphragm, 32: upper partition bracket, 34: lower partition bracket, 50: closing projection , 58: movable rubber film, 68: relief hole, 70: pressure receiving chamber, 72: equilibrium chamber, 78: orifice passage

Claims (5)

The first mounting member and the second mounting member are connected by a main rubber elastic body, and a pressure receiving chamber in which a part of a wall portion is configured by the main rubber elastic body and incompressible fluid is enclosed, and a flexible An equilibrium chamber in which a part of the wall portion is formed of an insulative film and in which an incompressible fluid is sealed is formed, and the pressure receiving chamber and the equilibrium chamber are communicated with each other by an orifice passage. A movable rubber film is disposed therebetween so that the pressure of the pressure receiving chamber is exerted on one surface of the movable rubber film, and the pressure of the equilibrium chamber is exerted on the other surface of the movable rubber film. In a fluid-filled vibration isolator that constitutes a hydraulic pressure absorption mechanism that absorbs minute pressure fluctuations in the pressure receiving chamber by
A relief hole is formed through the movable rubber film, and a contact plate supported by the second mounting member is disposed on the equilibrium chamber side of the movable rubber film. The relief projection is formed by projecting and forming a closure protrusion having a tapered circular inclined outer peripheral surface at a position corresponding to the hole, and the closure protrusion is fitted into the relief hole of the movable rubber film. A fluid-filled vibration isolator characterized by being closed.   A limiting plate supported by the second mounting member is disposed on the pressure-receiving chamber side of the movable rubber film, and the limiting plate is opposed to the movable rubber film at a predetermined distance. In addition, a through-hole penetrating the restriction plate in the thickness direction is formed, and the relief hole is in contact with the restriction plate of the movable rubber film due to the displacement of the movable rubber film toward the pressure receiving chamber. The fluid filled type vibration damping device according to claim 1, wherein the fluid-filled type vibration damping device is configured to communicate with the pressure receiving chamber through the through hole.   The fluid-filled vibration isolator according to claim 2, wherein a shock-absorbing protrusion that protrudes from the periphery of the relief hole toward the restriction plate and contacts the restriction plate is integrally formed with the movable rubber film.   In the movable rubber film, a fitting recess having an inner surface shape corresponding to the outer surface shape of the closing projection is formed at the balance chamber side at a position corresponding to the closing projection of the contact plate. The fluid according to claim 2, wherein the relief hole is formed by an opening hole formed in a wall portion located on the pressure receiving chamber side in the fitting recess and the fitting recess. Enclosed vibration isolator.   5. The fluid-filled vibration isolator according to claim 2, wherein an opposing recess is formed in the restriction plate so as to open toward the movable rubber film at a position corresponding to the relief hole.

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