JP2019019965A - Fluid encapsulated vibration prevention device - Google Patents

Abstract

To provide a fluid encapsulated vibration prevention device in novel structure capable of implementing a vibration prevention effect with respect to vibration over a wide frequency range and prevention of cavitation noise in simple structure which reduces the number of components.SOLUTION: The present invention relates to a fluid encapsulated vibration prevention device 10 in which a first orifice passage 94, a second orifice passage 96 tuned in a higher frequency than the second orifice passage 94 and a short-circuit passage 98 are provided while mutually communicating a pressure receiving chamber 90 and a balancing chamber 92. A valve body 78 for restricting a fluid flowing amount of the second orifice passage 96 is provided in a communication hole 76 of an elastic plate member 70 constituting the second orifice passage 96. A relief valve 82 consisting of an outer peripheral portion of the elastic plate member 70 is elastically deformed so as to be rolled up closer to the pressure receiving chamber 90, such that the short-circuit passage 98 is switched from a cut-off state to a communicated state.SELECTED DRAWING: Figure 1

Description

  The present invention relates to an anti-vibration device applied to, for example, an engine mount of an automobile, and more particularly to a fluid-filled anti-vibration device that utilizes an anti-vibration effect based on a fluid action of a fluid enclosed inside.

  2. Description of the Related Art Conventionally, there has been known a vibration isolating apparatus that is interposed between members constituting a vibration transmission system such as a power unit of an automobile and a vehicle body, and that these members mutually provide vibration isolation connection or vibration isolation support. As described in, for example, Japanese Patent No. 5432132 (Patent Document 1), this vibration isolator forms a vibration transmission system with a first attachment member attached to one member constituting the vibration transmission system. A second attachment member attached to the other member is elastically connected by a main rubber elastic body. As one type of vibration isolator, a fluid-filled vibration isolator that utilizes the flow action of an incompressible fluid enclosed therein has also been proposed. The fluid-filled vibration isolator has a structure in which an incompressible fluid is sealed in a pressure receiving chamber and an equilibrium chamber formed inside, and the pressure receiving chamber and the equilibrium chamber communicate with each other through a low-frequency orifice passage. doing.

  By the way, in the fluid-filled vibration isolator, the low-frequency orifice passage exhibits an excellent vibration-proof effect based on the resonance action of the fluid with respect to the vibration of the frequency that the low-frequency orifice passage is tuned in advance. There is a problem that it is difficult to obtain an effective anti-vibration effect with respect to vibrations of frequencies outside the frequency. In particular, when vibration is input in a frequency range higher than the tuning frequency of the low-frequency orifice passage, the low-frequency orifice passage is substantially cut off by anti-resonance action, which causes a significant deterioration in vibration-proof performance due to the high dynamic spring. It becomes.

  Therefore, as in Patent Document 1, a structure in which a high-frequency orifice passage tuned to a higher frequency than the low-frequency orifice passage is formed in order to reduce the dynamic spring at the time of vibration input in a high frequency range. Yes. According to this, even when vibration is input at a frequency higher than the tuning frequency of the low frequency orifice passage, an excellent vibration isolation effect based on the resonance action of the fluid flowing through the high frequency orifice passage is exhibited. In Patent Document 1, a valve body that switches between a communication state and a cutoff state of the high-frequency orifice passage is provided, and the high-frequency orifice passage is blocked by the valve body when vibration is input in a frequency range in which the low-frequency orifice passage is tuned. Thus, the anti-vibration effect by the low frequency orifice passage is efficiently exhibited.

  Further, in the fluid filled type vibration damping device, abnormal noise due to cavitation may occur when the internal pressure of the pressure receiving chamber greatly decreases locally. Therefore, in FIG. 1 of Patent Document 1 and the like, a short-circuit hole that communicates the pressure-receiving chamber and the equilibrium chamber is formed, and when the internal pressure of the pressure-receiving chamber is significantly reduced with respect to the internal pressure of the equilibrium chamber, As the fluid moves from the equilibrium chamber to the pressure receiving chamber, a decrease in the internal pressure of the pressure receiving chamber is suppressed. In Patent Document 1, a one-way valve that blocks a short-circuit hole at the time of normal vibration input in which cavitation is not a problem is provided, and fluid flow from the equilibrium chamber to the pressure receiving chamber occurs when the internal pressure difference between the pressure receiving chamber and the equilibrium chamber is large. As a result, the anti-vibration performance against normal vibration input is ensured.

  However, in the fluid-filled vibration isolator shown in Patent Document 1, a valve body that switches communication and blocking of the high-frequency orifice passage and a one-way valve that switches communication and blocking of the short-circuit hole are provided independently of each other. It has a structure, the number of parts is increased, and it is necessary to assemble the valve body and the one-way valve to the partition member, respectively, and secure the space for arranging the valve body and the one-way valve in the partition member. There was a need to do.

Japanese Patent No. 5432132

  The present invention has been made in the background of the above-mentioned circumstances, and its solution is to provide an effective anti-vibration effect in a wider frequency range and prevention of abnormal noise due to cavitation, and a simple structure with a small number of components. An object of the present invention is to provide a fluid-filled vibration isolator having a novel structure that can be realized by the above.

  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.

  That is, according to the first aspect of the present invention, the first attachment member and the second attachment member are elastically connected by the main rubber elastic body, and the pressure receiving chamber and the equilibrium chamber each encapsulating an incompressible fluid are provided. Formed on both sides of the partition member, the first orifice passage communicating the pressure receiving chamber and the equilibrium chamber with each other, and the pressure receiving chamber and the equilibrium chamber communicating with each other at a higher frequency than the first orifice passage. A tuned second orifice passage is provided, and a valve body for restricting the amount of fluid flow in the second orifice passage is provided, while the pressure receiving chamber and the equilibrium chamber communicate with each other. In the fluid filled type vibration damping device, in which a short-circuit passage is formed and a relief valve is provided to switch the short-circuit passage from a shut-off state to a communication state by a decrease in internal pressure of the pressure receiving chamber. And the second orifice passage is constituted by a communication hole provided in the elastic plate member, and the valve body is integrally formed in the communication hole in the elastic plate member. The relief valve is constituted by an outer peripheral portion of the elastic plate member, and the short circuit is caused by elastically deforming the relief valve so as to be turned up to the pressure receiving chamber side by a decrease in internal pressure of the pressure receiving chamber. The passage is configured to be switched from a blocked state to a connected state.

  According to the fluid-filled vibration isolator having the structure according to the first aspect, the vibration isolating effect based on the resonance action of the fluid flowing through the second orifice passage can be obtained by tuning the first orifice passage. Since it is exhibited at the time of vibration input at a frequency higher than the frequency, it is possible to obtain excellent vibration isolation performance against vibrations in a wider frequency range.

  In addition, when the vibration is input at a frequency at which the first orifice passage is tuned, the fluid flow amount in the second orifice passage is limited by the valve body, so that the fluid flow through the first orifice passage is efficiently performed. As a result, the vibration isolation effect by the first orifice passage is effectively exhibited.

  In addition, when the internal pressure is reduced to such an extent that cavitation becomes a problem in the pressure receiving chamber, the relief valve is elastically deformed so as to turn up to the pressure receiving chamber side due to the relative pressure difference between the pressure receiving chamber and the equilibrium chamber. Thus, the short-circuit passage is switched to the communication state, and the movement of the fluid through the short-circuit passage from the equilibrium chamber to the pressure receiving chamber is allowed. As a result, the decrease in the internal pressure of the pressure receiving chamber is resolved as quickly as possible, and the generation of abnormal noise due to cavitation is prevented.

  Further, the valve body for limiting the fluid flow amount in the second orifice passage and the relief valve for switching the short-circuit passage between the communication state and the cutoff state are integrally formed on the elastic plate member supported by the partition member. Therefore, the number of parts is reduced as compared with the case where the valve body and the relief valve are provided separately, thereby simplifying the structure and facilitating the assembling work at the time of manufacture. Moreover, the relief valve is provided on the outer peripheral portion of the elastic plate member, and is elastically deformed so as to be turned up toward the pressure receiving chamber, thereby switching the short-circuit path to the communication state, thereby providing a large relief valve. This makes it easy to tune the deformation characteristics of the relief valve with a greater degree of freedom.

  According to a second aspect of the present invention, in the fluid-filled vibration isolator described in the first aspect, the communication hole is a slit, and at least one opening edge in the width direction of the communication hole. Is provided with a plate-like valve element extending in the penetrating direction of the communication hole and extending in the length direction, and the communication hole can be closed by elastic deformation of the valve element.

  According to the second aspect, the communication hole is a narrow slit, and the valve body is provided on at least one opening edge in the width direction of the communication hole. The narrowing or blocking is quickly performed by elastic deformation, and for example, a vibration isolation effect by the first orifice passage can be advantageously obtained.

  According to a third aspect of the present invention, in the fluid-filled vibration isolator described in the first or second aspect, the pressure receiving chamber side relief hole in which the short-circuit passage is provided on the pressure receiving chamber side with respect to the relief valve. And an equilibrium chamber side relief hole provided closer to the equilibrium chamber than the relief valve, and the opening area of the pressure receiving chamber side relief hole is larger than the opening area of the equilibrium chamber side relief hole. It is what.

  According to the third aspect, since the pressure receiving chamber side relief hole on the pressure receiving chamber side is formed with a larger opening area than the relief valve in the short-circuit path, the elastic deformation of turning up to the pressure receiving chamber side of the relief valve is effectively performed. It is allowed to effectively prevent cavitation noise due to fluid movement through the short-circuit path.

  Further, the equilibrium chamber side relief hole on the equilibrium chamber side of the relief valve in the short-circuit passage is formed with a smaller opening area than the pressure receiving chamber side relief hole. Therefore, when a positive pressure is applied to the pressure receiving chamber where cavitation is not a problem, the internal pressure fluctuation of the pressure receiving chamber is effectively induced without being reduced by the elastic deformation of the relief valve, and is prevented by the first and second orifice passages. The vibration effect can be obtained efficiently. In addition, it is possible to avoid problems such as the relief valve entering the equilibrium chamber through the equilibrium chamber side relief hole.

  According to a fourth aspect of the present invention, in the fluid-filled vibration isolator described in any one of the first to third aspects, the elastic plate member has a disk shape, and the relief valve An outer peripheral portion of the elastic plate member is formed in an arcuate shape, and the pressure receiving chamber side surface of the relief valve is exposed to the pressure receiving chamber through a pressure receiving chamber side relief hole of the partition member constituting the short circuit passage. It is what.

  According to the fourth aspect, since the tip portion of the relief valve having an arcuate shape is made narrower and more easily deformed, the tip portion of the relief valve is quickly elastic when the internal pressure of the pressure receiving chamber decreases. By deforming, the short-circuit passage is quickly communicated on the tip side of the relief valve. In addition, when the input vibration is large, the relief valve is elastically deformed to the proximal end side, so that the cross-sectional area of the short-circuit passage is increased, and the flow rate of the fluid flowing from the equilibrium chamber to the pressure receiving chamber is sufficiently secured. The

  According to a fifth aspect of the present invention, in the fluid-filled vibration isolator described in any one of the first to fourth aspects, the surface on the equilibrium chamber side of the relief valve is provided on the partition member. In addition to being supported by the support surface, an equilibrium chamber side relief hole that constitutes the short-circuit path is provided to open to the support surface.

  According to the fifth aspect, since the amount of elastic deformation of the relief valve toward the equilibrium chamber is limited by the support surface of the partition member in which the equilibrium chamber side relief hole is opened, the pressure is received when a positive pressure is applied to the pressure receiving chamber. The increase in the internal pressure of the chamber is prevented from being relaxed by the elastic deformation of the relief valve, and the vibration isolation effect by the first and second orifice passages can be advantageously obtained.

  According to a sixth aspect of the present invention, in the fluid-filled vibration isolator described in any one of the first to fifth aspects, the relief valve is formed with a concave groove that opens on the pressure receiving chamber side surface. It is what has been.

  According to the sixth aspect, the relief valve can be easily elastically deformed so as to be turned up to the pressure receiving chamber side by being bent or bent at the concave groove forming portion, and the relief valve for switching the short-circuit passage to the communication state. Operation can be facilitated. Furthermore, since the relief valve is preferentially deformed at the formation portion of the concave groove, the deformation mode of the relief valve can be controlled by the shape, formation position, number of formations, and the like of the concave groove.

  According to a seventh aspect of the present invention, in the fluid-filled vibration isolator described in any one of the first to sixth aspects, positioning means for relatively positioning the elastic plate member and the partition member is provided. It is provided between the elastic plate member and the partition member.

  According to the seventh aspect, by relatively positioning the elastic plate member and the partition member, the elastic plate member can be arranged in an appropriate arrangement state in the partition member, and the use state in which vibration is input In this case, the elastic plate member and the partition member can be kept in an appropriate arrangement state.

  According to an eighth aspect of the present invention, in the fluid-filled vibration isolator described in the seventh aspect, the positioning hole that penetrates the elastic plate member in the thickness direction includes the communication hole and the valve in the elastic plate member. It is formed in the part which removed the body and the said relief valve, and the said positioning means is comprised by the positioning protrusion provided in the said partition member being penetrated by this positioning hole.

  According to the eighth aspect, since the positioning means has a structure in which the positioning protrusion of the partition member is inserted into the positioning hole of the elastic plate member, the elastic plate member and the partition member can be positioned with high reliability. it can. Therefore, the elastic plate member and the partition member are reliably arranged at appropriate positions, and it is also possible to prevent the elastic plate member from coming off the partition member and entering the pressure receiving chamber or the equilibrium chamber at the time of vibration input.

  According to the present invention, by integrally forming the valve body for switching communication and blocking of the second orifice passage and the relief valve for switching communication and blocking of the short-circuit passage on the elastic plate member supported by the partition member, Compared to the case where the valve body and the relief valve are provided separately, the number of parts is reduced, and the structure is simplified and the assembly work at the time of manufacture is facilitated. In addition, the relief valve is provided on the outer peripheral portion of the elastic plate member, and the relief valve is elastically deformed so as to be turned up to the pressure receiving chamber side so that the short-circuit path is switched to the communication state. The degree of freedom of design, such as the free length and shape, is large, and the deformation characteristics can be tuned with a greater degree of freedom.

Sectional drawing which shows the engine mount as 1st embodiment of this invention. It is an expanded sectional view of the partition member with an elastic board member which comprises the engine mount shown in FIG. 1, Comprising: The figure corresponded to the II-II cross section of FIG. The top view of the partition member shown in FIG. The bottom view of the partition member shown in FIG. The disassembled perspective view of the partition member shown in FIG. The front view of the partition member main body which comprises the partition member shown in FIG. The top view of the partition member main body shown in FIG. The bottom view of the partition member main body shown in FIG. The front view of the cover member which comprises the partition member shown in FIG. FIG. 10 is a plan view of the lid member shown in FIG. 9. FIG. 10 is a bottom view of the lid member shown in FIG. 9. The front view of the elastic board member which comprises the partition member shown in FIG. The top view of the elastic board member shown in FIG. The bottom view of the elastic board member shown in FIG. XV-XV sectional drawing of FIG. It is sectional drawing which expands and shows the principal part of the engine mount shown in FIG. 1, Comprising: The figure which shows the state which the internal pressure of the pressure receiving chamber fell greatly.

  Embodiments of the present invention will be described below with reference to the drawings.

  FIG. 1 shows an engine mount 10 for an automobile as a first embodiment of a fluid filled type vibration damping device having a structure according to the present invention. The engine mount 10 has a structure in which a first mounting member 12 and a second mounting member 14 are elastically connected to each other by a main rubber elastic body 16. In the following description, in principle, the vertical direction is the vertical direction in FIG. 1, which is the axial direction, the horizontal direction is the horizontal direction in FIG. 1, and the front-back direction is the direction perpendicular to the plane of FIG. Say each.

  More specifically, the first attachment member 12 is a highly rigid member made of metal or the like, and has a substantially cylindrical attachment portion 18 as a whole. Further, an annular plate-like portion 20 that protrudes to the outer periphery is provided at a lower portion of the attachment portion 18, and a substantially hemispherical fixing portion 22 that protrudes downward from the attachment portion 18 is integrally formed. Furthermore, the first mounting member 12 is formed with a mounting screw hole 24 extending linearly up and down on the central axis, and is open to the upper surface of the mounting portion 18.

  The second mounting member 14 is a high-rigidity member similar to the first mounting member 12 and has a thin, large-diameter, generally cylindrical shape as a whole, with the upper portion gradually increasing in diameter toward the top. A tapered portion 26 is provided, and a flange portion 28 that protrudes toward the outer periphery is integrally formed at the upper end of the tapered portion 26.

  And the 1st attachment member 12 and the 2nd attachment member 14 are arrange | positioned up and down on the substantially the same central axis, and these 1st attachment members 12 and the 2nd attachment members 14 are main body rubber elastic bodies. 16 are elastically connected to each other. The main rubber elastic body 16 has a generally frustoconical shape as a whole, and the first mounting member 12 is vulcanized and bonded to the upper end which is the end on the small diameter side, and the end on the large diameter side The second mounting member 14 is vulcanized and bonded to the outer peripheral surface of the lower end portion. The main rubber elastic body 16 of the present embodiment is formed as an integrally vulcanized molded product including the first mounting member 12 and the second mounting member 14.

  Further, a large-diameter recess 30 that opens to the lower surface is formed in the lower part of the main rubber elastic body 16. The large-diameter recess 30 has a substantially mortar shape in the opposite direction, and a thin-walled cylindrical sealing rubber layer 32 extending downward is integrally formed with the main rubber elastic body 16 at the periphery of the opening. The mounting member 14 is fixed to the inner peripheral surface.

  A flexible film 34 is attached to the second attachment member 14. The flexible film 34 is made of thin rubber or resin elastomer and can be easily deformed. Further, an annular fixing member 36 is vulcanized and bonded to the outer peripheral surface of the flexible film 34.

  The flexible film 34 is inserted from below into the inner peripheral side of the second mounting member 14, and the fixing member 36 is pressed against the seal rubber layer 32 covering the inner peripheral surface of the second mounting member 14. Thus, it is attached to the second attachment member 14. Note that the second mounting member 14 is fixed by subjecting the second mounting member 14 to diameter reduction processing such as an eight-way drawing in a state where the fixing member 36 is inserted into the inner peripheral side of the second mounting member 14. The flexible film 34 is attached to the second attachment member 14 by being fitted to the member 36 via the seal rubber layer 32.

  As described above, the flexible membrane 34 is attached to the second mounting member 14, so that a fluid-sealed region in which an incompressible fluid is sealed between the main rubber elastic body 16 and the flexible membrane 34. 38 is fluid-tightly defined with respect to the external space. The incompressible fluid sealed in the fluid sealing region 38 is not particularly limited. For example, liquid such as water, ethylene glycol, alkylene glycol, polyalkylene glycol, silicone oil, or a mixture thereof may be used. Preferably employed. Further, in order to advantageously obtain a vibration isolation effect based on the fluid flow action described later, the incompressible fluid enclosed in the fluid enclosure region 38 is preferably a low viscosity fluid of 0.1 Pa · s or less. . The incompressible fluid may be sealed in the fluid sealing region 38 after the flexible membrane 34 is attached to the second mounting member 14 to form the fluid sealing region 38. The assembly process of the flexible film 34 to the second mounting member 14 is performed in a water tank filled with an incompressible fluid, thereby simultaneously mounting the flexible film 34 to the second mounting member 14. It is also possible to enclose in the fluid enclosing region 38.

  A partition member 40 is disposed in the fluid sealing region 38. The partition member 40 is a hard member formed of metal, synthetic resin, or the like, and has a substantially disc shape as shown in FIGS. 2 to 4, and the partition member main body as shown in FIG. 42 and a cover member 44 are combined. In FIG. 5, the opening on the pressure receiving chamber 90 (described later) side of the first orifice passage 94 (described later) is not shown.

  As shown in FIGS. 6 to 8, the partition member main body 42 has a substantially disk shape as a whole, and is formed with a substantially circular central recess 46 opened to the top surface when viewed from above. The central recess 46 has a step 48 formed on the inner peripheral surface, and the lower side of the step 48 has a smaller diameter than the upper side. Further, three positioning protrusions 50, 50, 50 protrude from the bottom surface of the central recess 46 in the partition member main body 42. The positioning protrusion 50 has a substantially cylindrical shape with a small diameter, and the upper end is located above the step 48 and reaches the large diameter portion of the central recess 46, and is opened to the upper surface and has an inner peripheral surface. And a connecting screw hole 52 formed with a screw thread.

  Furthermore, a lower slit 54 penetrating vertically is formed in the bottom wall of the central recess 46 in the partition member main body 42. The lower slit 54 is a hole having a substantially rectangular cross section in which the width dimension in the left-right direction (the left-right direction in FIG. 7) is reduced, and the two positioning protrusions 50 on the left and right sides across the lower slit 54. 50, and one positioning protrusion 50 is disposed on the left and right sides with the lower slit 54 interposed therebetween.

  Furthermore, a lower relief hole 56 is formed in the bottom wall of the central recess 46 in the partition member main body 42 as an equilibrium chamber side relief hole penetrating vertically. As shown in FIGS. 7 and 8, the lower relief hole 56 is a hole having a substantially rectangular cross section in which the width dimension in the left-right direction is reduced, and is the center portion in the front-rear direction and the left-right direction on the bottom wall of the central recess 46. The hole cross-sectional area is made smaller than that of the lower slit 54.

  Furthermore, the partition member main body 42 is formed with a circumferential groove 58 that opens to the outer peripheral surface and extends in the circumferential direction with a length less than one round. The circumferential groove 58 can also be formed so as to extend for a length of one or more rounds according to the vibration isolation characteristics required for the engine mount 10.

  As shown in FIGS. 9 to 11, the lid member 44 has a substantially arcuate plate shape in a top view. In this embodiment, the outer peripheral surface has a dominant arc shape in a top view with a central angle larger than that of a semicircular shape. have.

  Further, the lid member 44 is formed with three connecting recesses 60, 60, 60 opened to the lower surface. As shown in FIG. 11, the connecting recess 60 is a recess having a small-diameter circular cross section. In the present embodiment, the two connecting recesses 60 are formed along the strings of the lid member 44 that is bowed when viewed from above. , 60 are disposed, and one connecting recess 60 is disposed further away from the string. Further, as shown in FIGS. 10 and 11, screw insertion holes 62 penetrating vertically are respectively formed in the upper bottom wall portion of the connection recess 60. In addition, the screw insertion hole 62 of the present embodiment has an upper portion that is larger in diameter than the lower portion, and can accommodate a head portion of a screw 66 described later.

  Further, the lid member 44 is formed with an upper slit 64 penetrating in the thickness direction. The upper slit 64 of the present embodiment has a substantially rectangular hole cross section as a whole, and has a linear shape extending substantially parallel to the chord of the lid member 44 that is bowed when viewed from above. Two connecting recesses 60, 60 are arranged between the string of the lid member 44 and the upper slit 64, and the upper slit 64 is arranged in the width direction of the two connecting recesses 60, 60 (in FIG. 10). The one connecting recess 60 is arranged on the opposite side of the left and right direction.

  The lid member 44 is inserted into the central recess 46 of the partition member main body 42. The lid member 44 is disposed on the upper portion of the central recess 46 having a large diameter, and the outer peripheral end portion of the lower surface is superimposed on the step 48 of the partition member main body 42, and is connected to the connection recess 60 of the lid member 44. The positioning protrusion 50 of the partition member main body 42 is inserted, and the screw 66 inserted from above into the screw insertion hole 62 of the lid member 44 is screwed into the connecting screw hole 52 of the positioning protrusion 50, The lid member 44 is fixed to the partition member main body 42. In the present embodiment, the three positioning protrusions 50 are inserted so that each positioning protrusion 50 is inserted into the corresponding connecting recess 60 and the relative orientation of the lid member 44 and the partition member main body 42 is uniquely set. The arrangement of the portions 50, 50, 50 and the three connecting recesses 60, 60, 60 corresponding to them is set.

  Further, between the partition member main body 42 and the lid member 44 fixed to each other, an accommodation space 68 formed at the lower portion of the central recess 46 is formed. An elastic plate member 70 is accommodated in the accommodation space 68. The elastic plate member 70 is formed of rubber, synthetic resin elastomer, or the like, and has a substantially disk shape as a whole as shown in FIGS. A large number of small projections 71 are dispersed and integrally formed on the upper and lower surfaces of the elastic plate member 70. In addition, the 1st seal protrusion 72 extended in the circumferential direction and protruded on the outer side of an up-down direction is formed in the upper-lower both surfaces at the outer peripheral edge part in the elastic board member 70. As shown in FIG.

  Further, the elastic plate member 70 includes three positioning holes 74, 74, 74 penetrating in the thickness direction, and the sectional shape and arrangement of the three positioning holes 74, 74, 74 are three of the partition member main body 42. Corresponding to the two positioning protrusions 50, 50, 50. The three positioning holes 74, 74, 74 are all provided at positions away from a communication hole 76 and a relief valve 82 described later.

  Furthermore, the elastic plate member 70 is formed with a communication hole 76 penetrating vertically. The communication hole 76 is a narrow slit corresponding to the lower slit 54 of the partition member main body 42 and the upper slit 64 of the lid member 44. As shown in FIGS. 13 and 14, second seal protrusions 77 are formed over the entire periphery of the opening peripheral portions on the upper and lower sides of the communication hole 76.

  Valve bodies 78 and 78 are provided at the opening ends of both sides of the communication hole 76 in the width direction (left and right in FIG. 13). The valve bodies 78, 78 are arranged substantially in parallel to face each other at a predetermined distance in the width direction of the communication hole 76, and extend in the penetrating direction of the communication hole 76 in the length direction (in FIG. 13). The upper and lower ends of the elastic plate member 70 are integrally connected to the inner surface of the communication hole 76. In addition, each valve element 78 is spread so as to gradually incline toward the other valve element 78 from the proximal end, which is the connection side to the elastic plate member 70, toward the distal end side. Further, the valve body 78 is integrally formed with a buffer protrusion 80 that protrudes toward the base end side. The one valve element 78 is elastically deformed in a direction approaching the other valve element 78 and comes into contact with the buffer protrusion 80, whereby the communication hole 76 is blocked by the valve element 78. In the present embodiment, the two valve bodies 78, 78 are provided in the communication hole 76, but only one of the valve bodies 78 may be provided.

  Further, a relief valve 82 is provided on a part of the outer circumferential portion of the elastic plate member 70 in the circumferential direction. The relief valve 82 has a substantially arcuate plate shape in a top view, and in this embodiment, has a subarc-shaped outer peripheral surface having a central angle smaller than a semicircle in a top view. The relief valve 82 has a plurality of small protrusions 71 protruding from the lower surface, and two concave grooves 84a and 84b formed on the upper surface. The concave groove 84 is a linear groove extending substantially parallel to the edge in the width direction of the communication hole 76, and one concave groove 84 a is formed at the proximal end portion of the relief valve 82 and the other concave groove. 84b is formed in an intermediate portion that is distant from the concave groove 84a toward the distal end side of the relief valve 82. It should be noted that a third seal protrusion 86 extending along the concave groove 84a is provided on both the upper and lower surfaces at the boundary portion between the relief valve 82 and the other portion of the elastic plate member 70 so as to protrude outward in the vertical direction. .

  Thus, the valve bodies 78 and 78 and the relief valve 82 are all provided integrally with the elastic plate member 70. In this embodiment, the valve bodies 78 and 78 and the relief valve 82 are integrally formed of a rubber elastic body.

  The elastic plate member 70 having such a structure is disposed in the accommodation space 68 of the partition member 40. That is, the elastic plate member 70 is inserted into the central recess 46 of the partition member main body 42 from above before combining the partition member main body 42 and the lid member 44, and the three positioning protrusions 50, The positioning means 87 for positioning the elastic plate member 70 with respect to the partition member main body 42 by inserting 50, 50 into the corresponding positioning holes 74 of the elastic plate member 70 is the elastic plate member 70 and the partition member main body 42. Composed between. Then, the lid member 44 is assembled to the partition member main body 42 from above, whereby the elastic plate member 70 is sandwiched between the partition member main body 42 and the lid member 44 and supported by the partition member 40. In the present embodiment, the elastic plate member 70 is compressed up and down between the partition member main body 42 and the lid member 44 at the portion where the small protrusion 71 and the first to third seal protrusions 72, 77, 86 are formed. Has been pinched. However, the elastic plate member 70 may not necessarily be sandwiched in a compressed state by the partition member 40, and may be disposed with a gap with respect to the inner surfaces of the upper and lower walls of the accommodation space 68 in the partition member 40. The partition member 40 can support the partition member 40 in such a manner that the partition member 40 can be slightly displaced in the vertical direction.

  Further, the communication hole 76 of the elastic plate member 70 is positioned with respect to the lower slit 54 of the partition member main body 42 and the upper slit 64 of the lid member 44, and the communication hole 76 and the upper and lower slits 64, 54 are in the vertical direction. It is continuous in a straight line. Further, the tip portions of the valve bodies 78 and 78 provided at the opening end of the communication hole 76 are inserted into one of the upper and lower slits 64 and 54.

  Furthermore, the relief valve 82 of the elastic plate member 70 is disposed at a position away from the lid member 44 (on the left side in FIG. 2 with respect to the lid member 44), and the upper surfaces thereof are the partition member main body 42 and the lid member 44. An upper relief hole 88 as a pressure receiving chamber side relief hole formed between the radial directions is exposed upward. Further, the lower surface of the relief valve 82 is superimposed on a support surface 89 formed by a part of the bottom surface of the central recess 46 and opens to the support surface 89 so that the bottom wall portion of the central recess 46 is moved up and down. The lower relief hole 56 is exposed downward. The lower relief hole 56 is positioned closer to the distal end side of the relief valve 82 than the edge of the upper relief hole 88 on the lid member 44 side, and the entire lower relief hole 56 overlaps with the upper relief hole 88 in the vertical projection. In addition, the relief valve 82 is provided in the middle between the distal end and the proximal end, and is disposed at a position biased toward the proximal end. The upper relief hole 88 is formed so as to expose the entire relief valve 82 upward, and the lower relief hole 56 is formed so as to expose only a part near the base end of the relief valve 82 downward. Has been. In short, the hole sectional area of the upper relief hole 88 is made larger than the hole sectional area of the lower relief hole 56.

  The partition member 40 to which the elastic plate member 70 is mounted is inserted from the lower side into the inner peripheral side of the second mounting member 14 before the flexible film 34 is mounted to the second mounting member 14. The outer peripheral surface is pressed against the seal rubber layer 32 that covers the inner peripheral surface of the second mounting member 14. Thereby, the partition member 40 is supported by the second attachment member 14 via the seal rubber layer 32. In addition, in the state where the partition member 40 is inserted into the inner peripheral side of the second mounting member 14, the second mounting member 14 is partitioned by subjecting the second mounting member 14 to diameter reduction processing such as an eight-way drawing. The member 40 is fitted through the seal rubber layer 32.

  Further, the outer peripheral end portion of the partition member main body 42 is disposed between the lower surface of the main rubber elastic body 16 and the upper surface of the fixing member 36, and the partition member 40 is vertically moved by the main rubber elastic body 16 and the fixing member 36. It is positioned.

  The partition member 40 attached in an interpolated state with respect to the second attachment member 14 is disposed so as to spread in the direction perpendicular to the axis in the fluid sealing region 38, and the fluid sealing region 38 is located vertically with the partition member 40 interposed therebetween. It is divided in two. That is, on the upper side of the partition member 40, a part of the wall portion is constituted by the main rubber elastic body 16, and a pressure receiving chamber 90 in which an internal pressure fluctuation is caused when vibration is input is formed. On the other hand, below the partition member 40, a part of the wall portion is constituted by the flexible film 34, and an equilibrium chamber 92 is formed in which volume change due to deformation of the flexible film 34 is allowed. . Note that both the pressure receiving chamber 90 and the equilibrium chamber 92 are filled with an incompressible fluid.

  Further, the opening on the outer peripheral side of the peripheral groove 58 of the partition member 40 is fluid-tightly covered by the second mounting member 14 covered with the seal rubber layer 32, and a tunnel-like flow path extending in the circumferential direction is formed. ing. One end of the tunnel-shaped flow path communicates with the pressure receiving chamber 90, and the other end communicates with the equilibrium chamber 92. Thus, the pressure receiving chamber 90 and the equilibrium chamber 92 communicate with each other. One orifice passage 94 is formed using the circumferential groove 58. The first orifice passage 94 is effective with respect to the vibration isolation target vibration by setting A / L, which is the ratio of the passage cross-sectional area A and the passage length L, according to the frequency of the vibration isolation target vibration. An anti-vibration effect can be obtained efficiently. In the present embodiment, the tuning frequency of the first orifice passage 94 is set to a low frequency of about 10 Hz corresponding to engine shake.

  The second orifice passage 96 that communicates the pressure receiving chamber 90 and the equilibrium chamber 92 with each other is formed by the communication hole 76 of the elastic plate member 70. In the present embodiment, since the valve bodies 78 and 78 are disposed in the communication hole 76, the second orifice passage 96 is formed between the opposing surfaces of the valve bodies 78 and 78 in the communication hole 76. The second orifice passage 96 has an upper end communicating with the pressure receiving chamber 90 through the upper slit 64 of the partition member 40 and a lower end communicating with the equilibrium chamber 92 through the lower slit 54 of the partition member 40. . The tuning frequency of the second orifice passage 96 is set higher than the tuning frequency of the first orifice passage 94. In the present embodiment, the tuning frequency of the second orifice passage 96 is set to a medium frequency of about 20 Hz to 50 Hz corresponding to idling vibration and a high frequency of about 100 Hz corresponding to running noise.

  The relief valve 82 provided in the elastic plate member 70 has an upper surface exposed to the pressure receiving chamber 90 through the upper relief hole 88, and the hydraulic pressure in the pressure receiving chamber 90 is exerted on the upper surface through the upper relief hole 88. The lower surface is exposed to the equilibrium chamber 92 through the lower relief hole 56, and the hydraulic pressure in the equilibrium chamber 92 is exerted on the lower surface through the lower relief hole 56. In other words, the short-circuit passage 98 that communicates the pressure-receiving chamber 90 and the equilibrium chamber 92 with each other is constituted by the upper relief hole 88, the accommodation space 68, and the lower relief hole 56, and the short-circuit passage 98 is formed by the relief valve. This is blocked by 82.

  The engine mount 10 having such a structure is mounted on the vehicle by the first mounting member 12 being mounted on a power unit (not shown) and the second mounting member 14 being mounted on a vehicle body (not shown). The power unit is connected to the vehicle body in an anti-vibration manner via the engine mount 10.

  When a low-frequency large-amplitude vibration corresponding to an engine shake is input to the engine mount 10 in the axial direction in such a state where the engine mount 10 is mounted on the vehicle, the relative pressure fluctuations of the pressure receiving chamber 90 and the equilibrium chamber 92 are changed. As a result, fluid flow through the first orifice passage 94 between the pressure receiving chamber 90 and the equilibrium chamber 92 is positively generated. Thereby, based on the fluid action such as the resonance action of the fluid flowing through the first orifice passage 94, the intended vibration isolation effect (high damping action) is exhibited.

  At the time of inputting low-frequency large-amplitude vibration in which the first orifice passage 94 is tuned, the valve body 78 projecting toward the pressure receiving chamber 90 and the valve body 78 projecting toward the balance chamber 92 correspond to fluctuations in internal pressure. The elastic deformation is repeated so as to fall alternately to the second orifice passage 96 side. Then, when the valve bodies 78 and 78 abut against the buffer protrusions 80 and 80, the opening of the second orifice passage 96 is closed, and the second orifice passage 96 is substantially prevented from fluid flow. Closed state. As a result, when a large amplitude vibration is input, the pressure fluctuation induced in the pressure receiving chamber 90 is prevented from escaping to the equilibrium chamber 92 through the second orifice passage 96, and the amount of fluid flow through the first orifice passage 94 is reduced. Since it is ensured efficiently, the intended vibration isolation effect (vibration damping effect, etc.) based on the resonance action of the fluid flowing through the first orifice passage 94 is effectively exhibited. In addition, since the deformed valve bodies 78 and 78 abut against the buffer protrusions 80 and 80, generation of hitting sound due to the contact of the valve bodies 78 and 78 is prevented.

  In the present embodiment, the communication hole 76 constituting the second orifice passage 96 is a slit having a narrow hole cross section, and one of each of the valve bodies 78, 78 is provided at the edges on both sides in the width direction of the communication hole 76. Therefore, the opening and closing of the communication hole 76 responds quickly to the elastic deformation of the valve bodies 78, 78, and the intended vibration isolation performance can be obtained more efficiently.

  On the other hand, when medium to high frequency small amplitude vibration is input, the first orifice passage 94 is substantially clogged by the antiresonant action of the fluid, and the valve bodies 78 and 78 are not elastically deformed. The second orifice passage 96 is maintained in communication. As a result, fluid flow through the second orifice passage 96 is efficiently generated, and a desired vibration-proof effect (low dynamic spring effect) based on the resonance action of the fluid flowing through the second orifice passage 96 and the like. Etc.) can be obtained effectively. As can be seen from the above description, the second orifice passage 96 can be switched between the communication state and the cutoff state by the valve bodies 78 and 78 according to the input vibration. The second orifice passage 96 formed in the communication state is blocked by the elastic deformation of the valve bodies 78 and 78. However, the valve bodies 78 and 78 only need to limit the fluid flow amount of the second orifice passage 96. For example, the valve bodies 78 and 78 are constricted without blocking the second orifice passage 96 to reduce the fluid flow amount. Also good.

  By the way, when the vehicle gets over a road step, vibration with a significantly large amplitude may be input to the engine mount 10. In such a case, the internal pressure of the pressure receiving chamber 90 is greatly reduced, which may cause separation of the gas phase due to cavitation, and noise generated by the shock wave when the generated bubbles disappear. May occur. Here, when the internal pressure of the pressure receiving chamber 90 is greatly lowered to the extent that cavitation can occur, the engine mount 10 of the present embodiment is elastic based on the internal pressure difference between the pressure receiving chamber 90 and the equilibrium chamber 92 as shown in FIG. The relief valve 82 of the plate member 70 is elastically deformed so as to be turned up to the pressure receiving chamber 90 side. As a result, the lower relief hole 56 covered with the relief valve 82 is opened, and the short-circuit passage 98 including the lower relief hole 56 is brought into a communication state. As a result, an efficient movement of the fluid through the short-circuit passage 98 from the equilibrium chamber 92 to the pressure receiving chamber 90 occurs, and the negative pressure due to a significant decrease in the internal pressure of the pressure receiving chamber 90 is relieved or eliminated. Therefore, it is possible to prevent the occurrence of cavitation due to a decrease in the internal pressure of the pressure receiving chamber 90, and to prevent abnormal noise caused by the cavitation.

  In particular, in the present embodiment, the relief valve 82 is provided on the outer peripheral portion of the elastic plate member 70, and the short-circuit passage 98 is switched to the communication state by elastically deforming so that the relief valve 82 is turned up. Yes. Therefore, the relief valve 82 can be easily formed relatively large, and the deformation characteristics of the relief valve 82 can be tuned with a large degree of freedom.

  Furthermore, in this embodiment, since the relief valve 82 is formed in the outer peripheral part of the disk-shaped elastic board member 70, it is made into an arch shape, Therefore The relief valve 82 becomes narrow gradually toward the front-end | tip. Yes. Accordingly, the distal end portion of the relief valve 82 is more easily deformed than the proximal end portion, and the distal end portion of the relief valve 82 is more quickly deformed with respect to the pressure drop of the pressure receiving chamber 90, so that the pressure receiving chamber 90 The negative pressure can be quickly reduced or eliminated, and when the pressure drop in the pressure receiving chamber 90 is large, the relief valve 82 is elastically deformed further to the base end side, so that a substantial passage of the short-circuit passage 98 is obtained. Large cross-sectional area is secured.

  Further, the relief valve 82 is formed with a concave groove 84 that extends substantially parallel to the string in a top view so as to open to the surface on the pressure receiving chamber 90 side, and the thickness dimension is reduced in the portion where the concave groove 84 is formed. ing. Since the groove 84 extends in a direction that bends in a valley when the relief valve 82 is elastically turned up, the relief valve 82 is easily deformed along the groove 84 in the portion where the groove 84 is formed. Thus, the elastic deformation of the relief valve 82 turning up is stably generated. In particular, since the relief valve 82 is easily elastically deformed so that the opening edges in the width direction of the concave groove 84 are close to each other, elastic deformation such that the relief valve 82 is turned up is allowed.

  Moreover, the relief valve 82 of the present embodiment is formed with two concave grooves 84a and 84b, and one concave groove 84a is disposed at the base end portion (the right end portion in FIG. 13) of the relief valve 82. In addition, the other concave groove 84b is arranged away from the one concave groove 84a toward the tip side. As a result, the relief valve 82 is elastically deformed at the portion where each concave groove 84 is formed, so that a sufficient amount of elastic deformation of the relief valve 82 can be obtained, and a substantial passage sectional area of the short-circuit passage 98 is ensured. It is possible to do. Therefore, the movement of the fluid through the short-circuit path 98 is sufficiently generated, and the cavitation is effectively relieved or eliminated.

  In addition, since the tip of the relief valve 82 having a small width dimension is elastically deformed quickly by the concave groove 84b, the short-circuit passage 98 is switched to a communicating state with excellent responsiveness to the negative pressure of the pressure receiving chamber 90, and the relief is performed. The valve 82 is elastically deformed even at the base end portion having the concave groove 84 a, so that a sufficient amount of fluid flows through the short-circuit passage 98. The deformation characteristics of the relief valve 82 can be tuned by adjusting the number, size, length, etc. of the concave grooves 84.

  It should be noted that the relief valve 82 is positive when a vibration that does not cause the occurrence of cavitation is input, that is, when a normal vibration that provides a vibration isolation effect by the orifice passages 94 and 96 is input, or when the pressure receiving chamber 90 is increased in pressure. When the pressure is reached, the short-circuit path 98 is held in a closed state. In this embodiment, the surface of the relief valve 82 on the side of the equilibrium chamber 92 is superimposed on the support surface 89 formed by the bottom surface of the central recess 46 of the partition member 40, and when the pressure receiving chamber 90 is positive pressure, Since the relief valve 82 is supported by the support surface 89, a decrease in the hydraulic pressure in the pressure receiving chamber 90 due to deformation of the relief valve 82 is prevented. In addition, in the short-circuit passage 98, the upper relief hole 88 provided on the pressure receiving chamber 90 side with respect to the relief valve 82 has a hole cross-sectional area larger than the lower relief hole 56 provided on the equilibrium chamber 92 side with respect to the relief valve 82. Therefore, elastic deformation of the relief valve 82 toward the pressure receiving chamber 90 is allowed by the upper relief hole 88, and elastic deformation of the relief valve 82 toward the equilibrium chamber 92 is prevented.

  Further, the lower relief hole 56 opens toward the proximal end portion of the relief valve 82, and the distal end portion of the relief valve 82 is supported by the support surface 89 of the partition member 40. Thereby, it is possible to prevent the relief valve 82 from being deformed so as to enter the lower relief hole 56, and it is also possible to prevent the relief valve 82 from being deformed so as to be turned up during normal vibration input.

  As understood from the above description, in the engine mount 10, the elastic plate member 70 supported by the partition member 40 includes the valve bodies 78 and 78 for switching between communication and blocking of the second orifice passage 96, and the short-circuit passage. A relief valve 82 for switching between communication and shut-off of 98 is integrally provided. Therefore, compared with the structure in which the valve bodies 78 and 78 and the relief valve 82 are provided separately, the arrangement area of the valve bodies 78 and 78 and the relief valve 82 in the partition member 40 can be reduced, and the engine mount 10 The size can be reduced, and the valve bodies 78 and 78 and the relief valve 82 can be simultaneously assembled as one part with respect to the partition member 40, thereby reducing the work process.

  Furthermore, the portion clamped by the partition member 40 is shared by the valve bodies 78 and 78 and the relief valve 82, so that the communication hole 76 in which the valve bodies 78 and 78 are arranged and the relief valve 82 are connected to the elastic plate member 70. In a larger proportion. Therefore, the operating characteristics of the valve bodies 78 and 78 and the relief valve 82 can be set with a greater degree of tuning freedom, and the opening area of the communication hole 76 can be secured to further increase the tuning frequency of the second orifice passage 96. It is also possible to set with a large degree of freedom.

  In addition, the communication hole 76 is a slit, and the relief valve 82 is arcuate when viewed from above, and the edge in the width direction of the communication hole 76 extends substantially parallel to the string of the relief valve 82. . Accordingly, the communication hole 76 and the relief valve 82 are arranged side by side in the left-right direction (the left-right direction in FIG. 13) of the elastic plate member 70, and the communication hole 76 and the relief valve 82 can be arranged efficiently. .

  In addition, the elastic plate member 70 includes a positioning hole 74 that penetrates up and down, and the partition member 40 includes a positioning protrusion 50 that protrudes upward from the bottom surface of the central recess 46, and the positioning protrusion 50 is positioned. Positioning means 87 for positioning the elastic plate member 70 with respect to the partition member 40 by being inserted into the hole 74 is configured. Thereby, even if a large internal pressure difference is generated between the pressure receiving chamber 90 and the equilibrium chamber 92, the problem that the elastic plate member 70 comes out of the accommodating space 68 of the partition member 40 and enters the pressure receiving chamber 90 or the equilibrium chamber 92 is avoided. can do.

  In addition, in the present embodiment, the three positioning holes 74, 74, 74 and the corresponding positioning protrusions 50 are provided, and the three positioning holes 74, 74, 74 are connected to the back and front of the elastic plate member 70. It is arranged so that the circumferential direction can be set uniquely. Specifically, two positioning holes 74 and 74 are formed on the relief valve 82 side across the communication hole 76, and one positioning hole 74 is formed on the opposite side of the relief valve 82 across the communication hole 76. Furthermore, the two positioning holes 74, 74 provided on the relief valve 82 side are arranged at positions that are asymmetric with respect to the center of the elastic plate member 70 in the front-rear direction (vertical direction in FIG. 13). Yes. Thereby, it can prevent that the elastic board member 70 is assembled | attached with the incorrect orientation with respect to the partition member 40, and the target performance can be obtained stably.

  As mentioned above, although embodiment of this invention was explained in full detail, this invention is not limited by the specific description. For example, in the above-described embodiment, the relief valve 82 is provided on a part of the outer peripheral portion of the elastic plate member 70, but the relief valve 82 is provided on the outer peripheral portion of the elastic plate member 70 over the entire circumference. It may be. In addition, when providing the relief valve 82 over the perimeter in this way, the recessed groove 84 can also be made into the cyclic | annular form continuous over a perimeter.

  Further, the relief valve 82 is not limited to an arcuate shape when viewed from above, and may be, for example, a quadrangle when viewed from above. Furthermore, the relief valve 82 can be tuned to the distal end side deformation characteristic and the proximal end side deformation characteristic, for example, by gradually or gradually thinning the relief valve 82 toward the distal end. The shape of the elastic plate member 70 including the relief valve 82 is not particularly limited as viewed from above, and may be, for example, a square plate shape. Further, in the elastic plate member 70, the relief characteristic can be tuned by thinning only the portion constituting the relief valve 82, for example.

  A plurality of short-circuit passages 98 provided with the relief valve 82 may be provided. Furthermore, a plurality of communication holes 76 including the valve body 78 can be provided.

  Further, the hole cross-sectional area and the number of the lower relief holes 56 formed, the relative position with respect to the relief valve 82, and the like can be appropriately changed according to required characteristics.

  For example, the positioning means can be configured by providing a recess on the outer peripheral surface of the elastic plate member 70 and providing a protrusion on the inner peripheral surface of the accommodation space 68 in the partition member 40 and combining the recess and the protrusion. The positioning means may not have a function of preventing the elastic plate member 70 from dropping out of the accommodation space 68. For example, the positioning means merely prevents rotation of the elastic plate member 70 in the accommodation space 68. good.

  In the above embodiment, the example in which the present invention is applied to the engine mount 10 has been described. However, the present invention can also be applied to other fluid-filled vibration isolator such as a subframe mount. Furthermore, the present invention is not only applied to a fluid-filled vibration isolator for automobiles but can also be applied to a fluid-filled vibration isolator used for motorcycles, railway vehicles, industrial vehicles, and the like.

10: engine mount (fluid-filled vibration isolator), 12: first mounting member, 14: second mounting member, 16: main rubber elastic body, 40: partition member, 50: positioning protrusion, 56: bottom Relief hole (equilibrium chamber side relief hole), 70: elastic plate member, 74: positioning hole, 76: communication hole, 78: valve body, 82: relief valve, 84: concave groove, 87: positioning means, 88: upper relief Hole (pressure receiving chamber side relief hole), 89: support surface, 90: pressure receiving chamber, 92: equilibrium chamber, 94: first orifice passage, 96: second orifice passage, 98: short circuit passage

Claims (8)

The first mounting member and the second mounting member are elastically connected by the main rubber elastic body, and a pressure receiving chamber and an equilibrium chamber each containing an incompressible fluid are formed on both sides of the partition member. A first orifice passage that communicates the pressure receiving chamber and the equilibrium chamber with each other, and a second orifice passage that communicates with the pressure receiving chamber and the equilibrium chamber and that is tuned to a higher frequency than the first orifice passage are provided. And a valve body for limiting the fluid flow rate of the second orifice passage is provided,
A fluid-filled type in which a short-circuit passage that connects the pressure-receiving chamber and the equilibrium chamber is formed, and a relief valve that switches the short-circuit passage from a shut-off state to a communication state when the internal pressure of the pressure-receiving chamber decreases In the vibration isolator,
An elastic plate member supported by the partition member is provided, and the second orifice passage is constituted by a communication hole provided in the elastic plate member, and the valve body is formed in the communication hole in the elastic plate member. Is integrally formed,
The relief valve is constituted by an outer peripheral portion of the elastic plate member, and the short-circuit path is cut off from the cut-off state by elastically deforming the relief valve so as to turn up to the pressure receiving chamber side due to a decrease in internal pressure of the pressure receiving chamber. A fluid-filled vibration isolator characterized by being switched to a communication state.   The communication hole is a slit, and at least one opening edge in the width direction of the communication hole is provided with the plate-like valve body extending in the penetrating direction of the communication hole and extending in the length direction. The fluid filled type vibration damping device according to claim 1, wherein the communication hole can be closed by elastically deforming the valve body.   The short circuit passage includes a pressure receiving chamber side relief hole provided closer to the pressure receiving chamber than the relief valve, and an equilibrium chamber side relief hole provided closer to the equilibrium chamber than the relief valve, and the pressure receiving The fluid-filled vibration isolator according to claim 1 or 2, wherein a hole cross-sectional area of the chamber-side relief hole is larger than a hole cross-sectional area of the equilibrium chamber-side relief hole.   The elastic plate member has a disc shape, and the relief valve is formed in an arcuate shape at the outer peripheral portion of the elastic plate member, and the pressure receiving chamber side surface of the relief valve constitutes the short-circuit passage The fluid-filled vibration isolator according to any one of claims 1 to 3, which is exposed to the pressure receiving chamber through a pressure receiving chamber side relief hole of the partition member.   A surface of the relief valve on the side of the equilibrium chamber is supported by a support surface provided on the partition member, and an equilibrium chamber side relief hole constituting the short-circuit passage is provided to open to the support surface. The fluid-filled vibration isolator according to any one of claims 1 to 4.   The fluid-filled type vibration damping device according to any one of claims 1 to 5, wherein a concave groove is formed in the relief valve so as to open on a surface on the pressure receiving chamber side.   The fluid-filled vibration isolator according to any one of claims 1 to 6, wherein positioning means for relatively positioning the elastic plate member and the partition member is provided between the elastic plate member and the partition member. .   A positioning hole that penetrates the elastic plate member in the thickness direction is formed in a portion of the elastic plate member that is separated from the communication hole, the valve body, and the relief valve, and a positioning protrusion provided in the partition member. The fluid filled type vibration damping device according to claim 7, wherein the positioning means is configured by inserting a portion into the positioning hole.