Fluid-filled vibration isolation device

Abstract

To provide a fluid sealing-type vibration isolation device having a novel structure which can effectively suppress cavitation.SOLUTION: An external peripheral end part of a movable film 68 comprises an abutment part 70 which partially abuts on a wall inner face 55 of an accommodation void space 66 at a pressure receiving chamber 84 side, and a seal part 72 which abuts on a wall inner face 65 of the accommodation void space 66 at an equilibrium chamber 86 side. The external peripheral end part of the movable film 68 is supported by a partitioning member 40, a clearance 80 is formed in an opposing clearance between an external peripheral face of the movable film 68 and an inner peripheral face of the accommodation void space 66, a communication path 82 communicating with the clearance 80 is formed in a position deviated from the abutment part 70 abutting on the wall inner face 55 of the accommodation void space 66 at the external peripheral end part of the movable film 68, a relief passage 94 for making the pressure receiving chamber 84 and the equilibrium chamber 86 communicate with each other by the separation of the external peripheral end part of the movable film 68 from the wall inner face 65 of the accommodation void space 66 by a pressure difference between the pressure receiving chamber 84 and the equilibrium chamber 86, includes the clearance 80 and the communication path 82.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a fluid-filled type vibration isolation device for use in engine mounts of automobiles and the like. [Background technology]

[0002] Conventionally, vibration-proof devices used for vibration-proof support of automobile power units have been known. In addition, JP 2013-231480 A (Patent Document 1) proposes a fluid-filled vibration-proof device with the aim of improving vibration-proof performance. The fluid-filled vibration-proof device has a structure in which a primary liquid chamber and a secondary liquid chamber filled with fluid are partitioned by a partition member. In addition, in Patent Document 1, an elastic membrane is provided on the partition member, and a vibration-proof effect is achieved by a fluid pressure absorbing action based on the deformation of the elastic membrane when vibration is input.

[0003] However, in a fluid-filled vibration-damping device, the generation of abnormal noise due to cavitation can be a problem. Cavitation is caused by a sudden drop in the internal pressure of the main liquid chamber. Therefore, in Patent Document 1, a relief valve for suppressing cavitation is provided in the center of the elastic membrane. The relief valve opens when the internal pressure of the main liquid chamber drops significantly, allowing fluid to flow from the sub-liquid chamber to the main liquid chamber, relieving the negative pressure in the main liquid chamber and suppressing cavitation. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2013-231480 A Summary of the Invention [Problem to be solved by the invention]

[0005] However, in the structure of Patent Document 1 in which a relief valve is provided in the center of the elastic membrane, it is difficult to increase the circumferential length of the relief valve, and it is difficult to increase the passage cross-sectional area of ​​the relief passage that can be switched between communication and blocking by the relief valve. As a result, Patent Document 1 revealed a new problem in that even if the relief valve opens, a sufficient amount of fluid cannot flow from the auxiliary liquid chamber to the main liquid chamber, and the effect of mitigating the negative pressure in the main liquid chamber may not be fully exerted.

[0006] An object of the present invention is to provide a fluid-filled type vibration isolation device with a novel structure that can effectively suppress cavitation. [Means for solving the problem]

[0007] The following describes preferred embodiments for understanding the present invention, but the embodiments described below are merely illustrative and may be combined with one another as appropriate, and the multiple components described in each embodiment may be recognized and used independently as far as possible, and may also be combined with any of the components described in another embodiment as appropriate. As a result, the present invention is not limited to the embodiments described below, and various other embodiments may be realized.

[0008] A first aspect is a fluid-filled vibration-damping device in which a pressure-receiving chamber and an equilibrium chamber are separated by a partition member, and a movable membrane is accommodated in an accommodation cavity formed in the partition member, the outer peripheral end of the movable membrane has an abutment portion that abuts partially in the circumferential direction against the inner wall surface of the accommodation cavity on the pressure-receiving chamber side, and a seal portion that abuts over the entire circumference against the inner wall surface of the accommodation cavity on the equilibrium chamber side, the outer peripheral end of the movable membrane is supported by the partition member, a gap is provided between the opposing outer peripheral surface of the movable membrane and the inner peripheral surface of the accommodation cavity, and a communication passage that communicates with the gap is provided at a position of the outer peripheral end of the movable membrane away from the corresponding contact portion with the inner wall surface of the accommodation cavity on the pressure-receiving chamber side, and a relief passage that communicates between the pressure-receiving chamber and the equilibrium chamber is configured to include the gap and the communication passage by the outer peripheral end of the movable membrane moving away from the inner wall surface of the accommodation cavity on the equilibrium chamber side due to the pressure difference between the pressure-receiving chamber and the equilibrium chamber. On the other hand, a plurality of elastic protrusions are provided in the circumferential direction on the outer peripheral end of the movable membrane, protruding toward the pressure-receiving chamber, and the elastic protrusions abut against the inner wall surface of the storage cavity on the pressure-receiving chamber side of the partition member to form an abutment portion, and the communication passage is formed between the plurality of elastic protrusions in the circumferential direction, and due to the action of the pressure difference between the pressure-receiving chamber and the equilibrium chamber on the movable membrane, the seal portion at the outer peripheral end of the movable membrane moves away from the inner wall surface on the equilibrium chamber side of the storage cavity between the elastic protrusions in the circumferential direction, and the relief passage is realized at the portion where the elastic protrusions are formed, while maintaining the respective abutment states between the elastic protrusions and the inner wall surface on the pressure-receiving chamber side of the storage cavity in the storage cavity, and between the seal portion and the inner wall surface on the equilibrium chamber side. It is something.

[0009] In a fluid-filled vibration isolation device constructed according to this embodiment, a relief passage is formed which opens when the internal pressure of the pressure-receiving chamber drops, connecting the pressure-receiving chamber and the equilibrium chamber. This allows the flow of fluid from the equilibrium chamber to the pressure-receiving chamber through the relief passage to quickly reduce the drop in internal pressure in the pressure-receiving chamber, preventing the occurrence of cavitation due to a significant drop in the internal pressure of the pressure-receiving chamber and preventing abnormal noise and other problems associated with cavitation.

[0010] The relief passage is located on the outer periphery of the cavity and includes a communication passage extending between the outer periphery of the movable membrane and the inner wall surface of the cavity on the pressure-receiving chamber side, and a gap formed between the outer periphery of the movable membrane and the inner periphery of the cavity. Therefore, the relief passage can be easily set to a long circumferential length without requiring an increase in the size of the fluid-filled vibration damping device, and a large passage cross-sectional area can be ensured. As a result, the fluid flow through the relief passage can quickly eliminate the drop in internal pressure of the pressure-receiving chamber, effectively preventing cavitation.

[0011] Under normal vibration input conditions where cavitation is not an issue, the seal portion of the movable membrane abuts against the inner wall surface of the accommodating cavity on the equilibrium chamber side, closing the relief passage and preventing short-circuiting between the pressure-receiving chamber and the equilibrium chamber through the relief passage. Therefore, during normal vibration input, internal pressure fluctuations in the pressure-receiving chamber are efficiently induced, and vibration-damping effects due to the flow action of the fluid and the liquid pressure absorption action of the movable membrane are effectively demonstrated. Furthermore, in the fluid-filled vibration-damping device constructed according to this embodiment, since the abutting portion is an elastic protrusion, depending on, for example, the deformation rigidity of the elastic protrusion and the movable membrane, the compression of the elastic protrusion allows the outer peripheral end of the movable membrane to be displaced toward the pressure-receiving chamber, and, for example, the seal portion can be separated from the inner wall surface of the accommodating space on the equilibrium chamber side over substantially the entire circumference in the circumferential direction to form a relief passage. Since multiple elastic protrusions are provided in the circumferential direction of the movable membrane, it is also possible to adjust the spring constant of the elastic protrusions by, for example, the circumferential width dimension or interval of the elastic protrusions, and set the threshold value of the internal pressure drop in the pressure-receiving chamber at which the relief passage is opened. Furthermore, with a fluid-filled vibration-damping device constructed according to this embodiment, depending on, for example, the deformation rigidity of the elastic protrusions and the movable membrane, when the internal pressure of the pressure-receiving chamber drops, the elastic protrusions and the seal parts maintain their respective contact states with the inner wall surfaces of the accommodating cavity on the pressure-receiving chamber side and the equilibrium chamber side at the positions where the elastic protrusions are formed at the outer peripheral end of the movable membrane, while the seal parts move away from the inner wall surface on the equilibrium chamber side at the circumferential intervals between the elastic protrusions at the outer peripheral end of the movable membrane, thereby forming a relief passage. That is, depending on the deformation rigidity of the elastic protrusions and the movable membrane, it is possible to form a relief passage by separating the seal parts from the inner wall surface on the equilibrium chamber side over substantially the entire circumferential circumference as in the first embodiment described later, or to form a relief passage by separating the seal parts from the inner wall surface on the equilibrium chamber side at the circumferential intervals between the elastic protrusions as in this embodiment and the third embodiment described later. In short, even in the case of a fluid-filled vibration-damping device relating to the second embodiment, for example, the relief passage can be configured in an appropriate manner depending on the deformation rigidity of the elastic protrusion and the movable membrane, thereby improving the design freedom of the elastic protrusion and the movable membrane, and ultimately the fluid-filled vibration-damping device.

[0016] No. two The embodiment is one In the fluid-filled type vibration-damping device described in the above aspect, the elastic protrusion has a tapered shape that contracts toward the protruding tip.

[0017] With a fluid-filled vibration damping device constructed according to this embodiment, the change in spring constant caused by compression of the elastic protrusion can be made nonlinear, so that when the internal pressure of the pressure-receiving chamber drops significantly, the elastic protrusion is prevented from completely collapsing, blocking the communication passage, and unintended blocking of the relief passage can be prevented.

[0018] No. three The embodiment is first or second In the fluid-filled type vibration-damping device described in the above aspect, the protruding tip surface of the elastic protrusion is formed into a spherical crown-shaped curved surface.

[0019] With a fluid-filled vibration-damping device constructed according to this embodiment, when the abutment portion is pressed against the inner wall surface of the accommodating cavity on the pressure-receiving chamber side, stress concentration on the surface of the abutment portion is avoided, improving the durability of the abutment portion. Also, for example, when a large positive pressure acts on the pressure-receiving chamber, causing the abutment portion of the movable membrane to move away from the inner wall surface of the accommodating cavity on the pressure-receiving chamber side, and then the release of the positive pressure causes the abutment portion to abut against the inner wall surface of the accommodating cavity on the pressure-receiving chamber side, the impact noise is reduced.

[0020] No. four The embodiment of the present invention is as follows: a pressure-receiving chamber and an equilibrium chamber are separated by a partition member, and a movable membrane is accommodated in an accommodation cavity formed in the partition member, the movable membrane having an outer peripheral end portion which is provided with an abutment portion which abuts partially in a circumferential direction against an inner wall surface of the accommodation cavity on the pressure-receiving chamber side, and a seal portion which abuts over the entire circumference against an inner wall surface of the accommodation cavity on the equilibrium chamber side, the movable membrane having an outer peripheral end portion supported by the partition member, a gap is provided between the opposing outer peripheral surface of the movable membrane and the inner peripheral surface of the accommodation cavity, and a communication passage which communicates with the gap is provided at a position of the movable membrane at the outer peripheral end portion away from the corresponding contact portion with the inner wall surface of the accommodation cavity on the pressure-receiving chamber side, the outer peripheral end portion of the movable membrane being moved away from the inner wall surface of the accommodation cavity on the equilibrium chamber side due to a pressure difference between the pressure-receiving chamber and the equilibrium chamber, thereby forming a relief passage which communicates between the pressure-receiving chamber and the equilibrium chamber, the relief passage including the gap and the communication passage,The partition member has a plurality of grooves that open to the outer circumferential portion of the inner wall surface of the accommodating space on the pressure-receiving chamber side, and the outer circumferential end of the movable membrane and the inner wall surface of the accommodating space on the pressure-receiving chamber side abut at portions circumferentially offset from the grooves, and the communicating passage is formed by the grooves.

[0021] In a fluid-filled vibration isolation device constructed according to this embodiment, a relief passage is formed which opens when the internal pressure of the pressure-receiving chamber drops, connecting the pressure-receiving chamber and the equilibrium chamber. This allows the flow of fluid from the equilibrium chamber to the pressure-receiving chamber through the relief passage to quickly reduce the drop in internal pressure in the pressure-receiving chamber, preventing the occurrence of cavitation due to a significant drop in the internal pressure of the pressure-receiving chamber and preventing abnormal noise and other problems associated with cavitation. The relief passage is located on the outer periphery of the cavity and includes a communication passage extending between the outer periphery of the movable membrane and the inner wall surface of the cavity on the pressure-receiving chamber side, and a gap formed between the outer periphery of the movable membrane and the inner periphery of the cavity. Therefore, the relief passage can be easily set to a long circumferential length without requiring an increase in the size of the fluid-filled vibration damping device, and a large passage cross-sectional area can be ensured. As a result, the fluid flow through the relief passage can quickly eliminate the drop in internal pressure of the pressure-receiving chamber, effectively preventing cavitation. Under normal vibration input conditions where cavitation is not an issue, the seal portion of the movable membrane abuts against the inner wall surface of the accommodating cavity on the equilibrium chamber side, closing the relief passage and preventing short-circuiting between the pressure-receiving chamber and the equilibrium chamber through the relief passage. Therefore, during normal vibration input, internal pressure fluctuations in the pressure-receiving chamber are efficiently induced, and vibration-damping effects due to the flow action of the fluid and the liquid pressure absorption action of the movable membrane are effectively demonstrated. Also, With a fluid-filled vibration-damping device constructed according to this embodiment, a groove is formed on the inner wall surface of the accommodation cavity on the pressure-receiving chamber side, so that a communication passage can be formed by the groove at a position away from the abutment portion without providing a protrusion or the like on the outer peripheral end of the movable membrane. When the internal pressure of the pressure-receiving chamber decreases, the abutment portion of the movable membrane is pressed against the inner wall surface of the accommodation cavity on the pressure-receiving chamber side at a position away from the groove and compressed, allowing the outer peripheral end of the movable membrane to displace toward the pressure-receiving chamber, and the seal portion is separated from the inner wall surface of the accommodation cavity on the equilibrium chamber side, forming a relief passage.

[0022] No. Five The first to fourth aspects are four In the fluid-filled type vibration damping device described in any one of the above aspects, the seal portion has a seal lip that protrudes toward the equilibrium chamber and is continuous over the entire periphery, and the seal lip abuts over the entire periphery against the inner wall surface of the accommodation space on the equilibrium chamber side. In this aspect, the outer peripheral end of the movable membrane may have a seal lip that protrudes toward the equilibrium chamber and is continuous over the entire periphery, and the seal lip abuts over the entire periphery against the inner wall surface of the accommodation space on the equilibrium chamber side.

[0023] In a fluid-filled vibration-damping device constructed in accordance with this embodiment, the sealing portion is provided with a sealing lip, which improves sealing performance by abutting the inner wall surface on the equilibrium chamber side of the accommodating space, thereby improving vibration-damping performance against the input of normal vibrations. A sixth aspect is a fluid-filled vibration-damping device in which a pressure-receiving chamber and an equilibrium chamber are separated by a partition member, and a movable membrane is accommodated in an accommodation space formed in the partition member, wherein an outer peripheral end of the movable membrane is provided with an abutment portion that abuts partially in a circumferential direction against an inner wall surface of the accommodation space on the pressure-receiving chamber side, and a seal portion that abuts over the entire circumference against an inner wall surface of the accommodation space on the equilibrium chamber side, the outer peripheral end of the movable membrane is supported by the partition member, a gap is provided between the opposing outer peripheral surface of the movable membrane and the inner peripheral surface of the accommodation space, and the outer peripheral end of the movable membrane is fixed to the accommodation space. Between the opposing surfaces of the inner wall surface on the pressure-receiving chamber side and the pressure-receiving chamber side surface of the movable membrane, a communication passage is provided which is connected to the gap at a position circumferentially away from the corresponding contact point with the inner wall surface on the pressure-receiving chamber side, and when the outer peripheral end of the movable membrane moves away from the inner wall surface on the equilibrium chamber side of the accommodating space due to the pressure difference between the pressure-receiving chamber and the equilibrium chamber, a relief passage connecting the pressure-receiving chamber and the equilibrium chamber is formed which includes the gap and the communication passage, and an orifice passage is provided in the outer peripheral portion of the partition member which extends circumferentially around the outer periphery of the relief passage and connects the pressure-receiving chamber and the equilibrium chamber. Effect of the Invention

[0024] According to the present invention, cavitation can be effectively suppressed. [Brief description of the drawings]

[0025] [Figure 1] FIG. 4 is a cross-sectional view showing an engine mount according to a first embodiment of the present invention, which corresponds to cross section II in FIG. [Diagram 2] FIG. 2 is a perspective view of a partition member constituting the engine mount shown in FIG. 1; [Diagram 3] FIG. 3 is a plan view of the partition member shown in FIG. [Figure 4] A perspective view of a movable membrane constituting the engine mount shown in FIG. [Diagram 5] FIG. 5 is a perspective view showing the movable membrane of FIG. 4 from a different angle. [Figure 6] Cross-sectional view of the movable membrane shown in FIG. [Figure 7] FIG. 2 is a cross-sectional view of the engine mount shown in FIG. 1, illustrating a communication state of the relief passage; [Figure 8] FIG. 1 is a cross-sectional view showing an engine mount according to a second embodiment of the present invention; [Figure 9] FIG. 8 is a cross-sectional view corresponding to FIG. 7 (corresponding to cross section II in FIG. 3 of the first embodiment), showing a partition member in an engine mount according to a third embodiment of the present invention in a state in which a relief passage is in communication with the partition member; [Figure 10] FIG. 10 is a cross-sectional view showing a movable film in a state where the partition member is removed in order to explain a deformation mode of the movable film disposed inside the partition member shown in FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0026] Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

[0027] Fig. 1 shows an engine mount 10 for an automobile as a first embodiment of a fluid-filled type vibration isolation device constructed in accordance with 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 by a main rubber elastic body 16. In the following explanation, the up-down direction basically refers to the up-down direction in Fig. 1, which is the mount axial direction.

[0028] The first mounting member 12 is integrally provided with a bracket mounting portion 18 having a rectangular tubular shape extending in the direction perpendicular to the axis, and a tubular fastening portion 20 extending downward from the periphery of a circular hole penetrating a lower wall portion of the bracket mounting portion 18. The first mounting member 12 can be obtained, for example, by pressing a metal plate.

[0029] The second mounting member 14 has a stepped, generally cylindrical shape, with an upper portion formed as a large-diameter cylindrical portion 22 and a lower portion formed as a small-diameter cylindrical portion 24 having a smaller diameter than the large-diameter cylindrical portion 22. The second mounting member 14 is disposed below the first mounting member 12 and generally on the same central axis, and a main rubber elastic body 16 is disposed between the first mounting member 12 and the second mounting member 14.

[0030] The main rubber elastic body 16 is formed into a generally truncated cone shape, with its upper portion, or small diameter side, vulcanization bonded to the fastening portion 20 of the first mounting member 12, and its outer peripheral surface, or large diameter side, vulcanization bonded to the large diameter tubular portion 22 of the second mounting member 14. The main rubber elastic body 16 is provided with a recess 26 that opens to the bottom and decreases in diameter upward. The recess 26 is located below the fastening portion 20 of the first mounting member 12, and located more inward than the small diameter tubular portion 24 of the second mounting member 14.

[0031] The bracket attachment portion 18 of the first mounting member 12 has a stopper rubber 28, which is formed integrally with the main rubber elastic body 16, fixed to its outer peripheral surface, and a fitting rubber 30, which is formed integrally with the main rubber elastic body 16, fixed to its inner peripheral surface. The inner peripheral surface of the small-diameter tubular portion 24 of the second mounting member 14 is covered with a seal rubber layer 32, which is formed integrally with the main rubber elastic body 16 and extends downward from the periphery of the recess 26.

[0032] A flexible film 34 is attached to the small diameter tube portion 24 of the second mounting member 14. The flexible film 34 is a flexible thin rubber film, and has slack in the vertical direction. An annular fixing member 36 is fixed to the outer circumferential end of the flexible film 34, and the fixing member 36 is fixed to the lower end of the small diameter tube portion 24 of the second mounting member 14. The fixing member 36 is fixed to the second mounting member 14 so that the flexible film 34 closes the lower opening of the second mounting member 14. The method of fixing the fixing member 36 to the second mounting member 14 is not particularly limited, but for example, the fixing member 36 is inserted into the inner periphery of the second mounting member 14, and the second mounting member 14 is subjected to a diameter reduction process to fix the fixing member 36 to the second mounting member 14. In addition, since a sealing rubber layer 32 is interposed between the small diameter cylindrical portion 24 of the second mounting member 14 and the fixing member 36, the space between the second mounting member 14 and the fixing member 36 is fluid-tightly sealed.

[0033] By attaching the flexible membrane 34 to the second mounting member 14 fixed to the main rubber elastic body 16, a fluid chamber 38 is defined between the opposing main rubber elastic body 16 and the flexible membrane 34 in a fluid-tight manner from the outside. A non-compressible fluid is sealed inside the fluid chamber 38. The non-compressible fluid is not particularly limited, but examples of the non-compressible fluid that can be used include water, ethylene glycol, alkylene glycol, polyalkylene glycol, silicone oil, and mixtures thereof.

[0034] A partition member 40 is disposed in the fluid chamber 38. The partition member 40 is formed in a substantially circular disk shape, and has a first partition plate 42 and a second partition plate 44, as shown in FIGS.

[0035] The first partition plate 42 is generally disk-shaped and is a hard member made of metal, synthetic resin, or the like. A circumferential groove 46 is formed at the outer peripheral end of the first partition plate 42, opening on the outer peripheral surface and extending in the circumferential direction. A circular central recess 48 is formed at the center of the first partition plate 42, opening on the upper surface at a position inner than the circumferential groove 46. A first central through hole 50 with a circular cross section penetrating the center in the vertical direction and a plurality of first outer peripheral through holes 52 penetrating the outer periphery in the vertical direction from the first central through hole 50 are formed at the bottom wall of the central recess 48. A circular accommodation recess 54 is formed at the center of the first partition plate 42, opening on the lower surface. The accommodation recess 54 has a larger diameter and a shallower bottom than the central recess 48, and the outer peripheral end of the accommodation recess 54 is located on the outer periphery of the central recess 48. A first wall inner surface 55, which is the inner surface of the upper bottom wall of the accommodating recess 54, has a radially intermediate portion that protrudes downward to form a first narrowed portion 56. The first central through hole 50 and the first outer peripheral through hole 52 are formed to pass through a common portion of the bottom wall portions of the central recess 48 and the accommodating recess 54, connecting the central recess 48 and the accommodating recess 54.

[0036] The second partition plate 44 is a hard member similar to the first partition plate 42, and is formed in a generally circular plate shape thinner than the first partition plate 42. A second central through hole 58 having a circular cross section penetrating in the vertical direction is formed in the center of the second partition plate 44. A plurality of second outer peripheral through holes 60 penetrating in the vertical direction are formed in a line in the circumferential direction on the outer periphery of the second central through hole 58 in the second partition plate 44. A second narrowed portion 62 protruding upward is provided between the second outer peripheral through holes 60 in the second partition plate 44 in the circumferential direction. A groove-shaped seal abutment portion 64 that opens on the upper surface and extends in the circumferential direction is provided on the outer periphery of the second narrowed portion 62 in the second partition plate 44. The upper surface of the second partition plate 44, which is composed of the seal abutment portion 64 and the inner peripheral portion of the seal abutment portion 64, is the second wall inner surface 65 that faces the first wall inner surface 55 in the partition member 40 in the vertical direction.

[0037] The first partition plate 42 and the second partition plate 44 are stacked on top of each other in the up-down direction. By stacking the second partition plate 44 on the lower surface of the first partition plate 42, the opening of the storage recess 54 of the first partition plate 42 is covered by the second partition plate 44, and a storage space 66 is formed between the first partition plate 42 and the second partition plate 44. The upper wall inner surface of the storage space 66, which faces a pressure-receiving chamber 84 described later, is formed by the first wall inner surface 55 of the first partition plate 42, and the upper wall inner surface of the storage space 66, which faces an equilibrium chamber 86 described later, is formed by the first wall inner surface 55 of the first partition plate 42. under The wall inner surface on the side is formed by the second wall inner surface 65 of the second partition plate 44. In the partition member 40, the first central through hole 50 and the first outer peripheral through hole 52 penetrate the upper wall portion of the accommodation cavity 66 and communicate with the accommodation cavity 66, and the second central through hole 58 and the second outer peripheral through hole 60 penetrate the lower wall portion of the accommodation cavity 66 and communicate with the accommodation cavity 66. The first central through hole 50 and the second central through hole 58 are arranged at positions corresponding to each other in the up-down direction, and the first outer peripheral through hole 52 and the second outer peripheral through hole 60 are arranged at positions corresponding to each other in the up-down direction.

[0038] A movable membrane 68 is disposed in the accommodation space 66 of the partition member 40. The movable membrane 68 has an overall disk shape, as shown in Figs. 4 and 5. The movable membrane 68 is formed of a rubber elastic body, and is allowed to elastically flex in the thickness direction. Depending on the required vibration-proofing performance and the deformation rigidity of the elastic protrusions 70 described later, the movable membrane 68 may have its partial or overall deformation characteristics adjusted by partially or entirely embedding a hard plate made of, for example, metal or resin.

[0039] An elastic protrusion 70 protruding upward is integrally formed on the outer peripheral end of the movable membrane 68. The elastic protrusion 70 protrudes upward from the outer peripheral end of the movable membrane 68 toward the pressure-receiving chamber 84 side described later. A plurality of elastic protrusions 70 are provided, spaced apart from each other in the circumferential direction. The elastic protrusions 70 have a substantially circular cross section. The elastic protrusions 70 are tapered so as to gradually shrink (become smaller in diameter) toward the protruding tip. The protruding tip surface of the elastic protrusions 70 may be a flat surface or a sharp-pointed convex surface, but in this embodiment, it is a spherical crown-shaped curved surface convex toward the protruding tip. The number and arrangement of the elastic protrusions 70 are not particularly limited, but in this embodiment, 16 elastic protrusions 70 are arranged at substantially equal intervals in the circumferential direction.

[0040] A seal portion 72 is provided at the outer peripheral end of the movable membrane 68. The seal portion 72 is a lower end portion at the outer peripheral end of the movable membrane 68, and in this embodiment, includes an outer peripheral lip 74 and an inner peripheral lip 76 as seal lips. As shown in an enlarged view in Fig. 6, the outer peripheral lip 74 protrudes downward from the outer peripheral edge of the movable membrane 68 toward an equilibrium chamber 86 described later, and is formed into an annular shape that extends continuously in the circumferential direction. The inner peripheral lip 76 protrudes downward on an inner periphery than the outer peripheral lip 74, and is formed into an annular shape that extends in the circumferential direction in parallel with the outer peripheral lip 74.

[0041] A plurality of buffer protrusions 78 are provided on both the upper and lower surfaces of the inner circumferential portion of the movable film 68. The buffer protrusions 78 are substantially hemispherical in shape. The buffer protrusions 78 have a smaller protruding height and width than the elastic protrusions 70. As shown in Figs. 4 to 6, the buffer protrusions 78 of this embodiment are minute protrusions, and a plurality of them are arranged in a substantially cross shape.

[0042] The movable membrane 68 is disposed in the accommodation space 66 of the partition member 40, as shown in FIG. 1. The movable membrane 68 has an outer peripheral end portion provided with an elastic protrusion 70 and a seal portion 72, which is located on the outer periphery of the first outer peripheral through hole 52 and the second outer peripheral through hole 60, and is disposed between the first partition plate 42 and the second partition plate 44. The outer peripheral end portion of the movable membrane 68 is sandwiched between the top and bottom of the first partition plate 42 and the second partition plate 44, with the elastic protrusion 70 being pressed against the first wall inner surface 55 of the first partition plate 42 and the seal portion 72 being pressed against the second wall inner surface 65 (seal abutment portion 64) of the second partition plate 44. The vertical dimension of the inner peripheral portion of the accommodation space 66 is larger than the vertical dimension of the inner peripheral portion of the movable membrane 68, and the inner peripheral portion of the movable membrane 68 is allowed to be displaced in the vertical direction accompanied by elastic deformation.

[0043] The outer diameter of the movable membrane 68 is smaller than the inner diameter of the accommodation cavity 66, and when the movable membrane 68 is disposed in the accommodation cavity 66, the outer peripheral surface of the movable membrane 68 and the inner peripheral wall surface of the accommodation cavity 66 face each other at a distance in the radial direction. As a result, an annular gap 80 extending in the circumferential direction is provided between the outer peripheral surface of the movable membrane 68 and the inner peripheral wall surface of the accommodation cavity 66 in the radial direction. In this embodiment, the gap 80 is provided over the entire circumference in the circumferential direction, but as long as the occurrence of cavitation is sufficiently prevented by a relief passage including the gap when the internal pressure of the pressure-receiving chamber 84 decreases as described below, the radial gap between the outer peripheral surface of the movable membrane and the inner peripheral wall surface of the accommodation cavity may be partial in the circumferential direction.

[0044] In a state where the elastic protrusion 70 is pressed against the upper wall inner surface of the accommodation cavity 66, a gap is maintained between the elastic protrusions 70, 70 arranged adjacent to each other in the circumferential direction. A communication passage 82 extending between the movable membrane 68 and the partition member 40 and communicating with the gap 80 is formed by the gap between the elastic protrusions 70, 70. In this embodiment, a plurality of communication passages 82 extend radially, but the communication passages do not necessarily need to extend in the radial direction of the movable membrane 68, and the number of communication passages formed is not limited as long as there are a plurality of communication passages. The outer peripheral end of the movable membrane 68 abuts against the wall inner surface (first wall inner surface 55) of the accommodation cavity 66 on the side of a pressure receiving chamber 84 described later at the portion where the elastic protrusion 70 is formed, and is separated from the first wall inner surface 55 at a position circumferentially deviating from the elastic protrusion 70. Therefore, the abutting portion abutting against the wall inner surface 55 of the accommodation cavity 66 on the side of the pressure receiving chamber 84 is constituted by the elastic protrusion 70 and is provided partially in the circumferential direction. In short, in this embodiment, a communication passage 82 that communicates with the gap 80 is provided at a position at the outer circumferential end of the movable film 68 that is circumferentially separated from the elastic protrusion 70 that serves as the abutment portion.

[0045] The seal portion 72 is pressed against the seal abutment portion 64 of the second partition plate 44 over the entire circumference, and the seal portion 72 constitutes a seal structure that prevents communication between the gap 80 and the second central through hole 58 and the second outer peripheral through hole 60. In this embodiment, the seal portion 72 includes an outer peripheral lip 74 and an inner peripheral lip 76, and both the outer peripheral lip 74 and the inner peripheral lip 76 are pressed against the second partition plate 44, thereby providing a double seal structure. However, a seal structure using one seal lip or a multiple seal structure using three or more seal lips may also be employed. Also, the seal lip may not be required.

[0046] In this manner, the outer peripheral end of the movable membrane 68, which is equipped with the elastic protrusion 70 and the seal portion 72, is supported by being sandwiched in the vertical direction by the partition member 40. The inner peripheral portion of the movable membrane 68 is allowed to undergo slight vertical displacement accompanied by bending deformation within the accommodating space 66.

[0047] The partition member 40 containing the movable membrane 68 is disposed in the fluid chamber 38 as shown in FIG. 1. The partition member 40 disposed in the fluid chamber 38 spreads in the direction perpendicular to the axis, and its outer peripheral surface is supported by being overlapped with the inner peripheral surface of the small diameter cylindrical portion 24 of the second mounting member 14. The outer peripheral surface of the partition member 40 is overlapped with the second mounting member 14 via the seal rubber layer 32, so that the overlapping surfaces of the partition member 40 and the second mounting member 14 are sealed fluid-tightly. The method of fixing the second mounting member 14 and the partition member 40 is not particularly limited, but for example, the second mounting member 14 is subjected to a diameter reduction process with the partition member 40 inserted into the inner circumference of the second mounting member 14, and the inner circumference of the second mounting member 14 and the outer circumference of the partition member 40 are pressed against each other via the seal rubber layer 32, thereby fixing them. Furthermore, by reducing the diameter of the second mounting member 14, the pre-compression of the main rubber elastic body 16, the attachment of the flexible membrane 34 to the second mounting member 14, and the attachment of the partition member 40 to the second mounting member 14 can be performed all at once.

[0048] The fluid chamber 38 is divided into two by the partition member 40, namely, a pressure-receiving chamber 84 and an equilibrium chamber 86. That is, the upper side of the fluid chamber 38 above the partition member 40 is the pressure-receiving chamber 84, the wall of which is partly constituted by the main rubber elastic body 16. The lower side of the fluid chamber 38 below the partition member 40 is the equilibrium chamber 86, the wall of which is partly constituted by the flexible membrane 34. Both the pressure-receiving chamber 84 and the equilibrium chamber 86 are filled with a non-compressible fluid, and the pressure-receiving chamber 84 experiences internal pressure fluctuations upon vibration input, while the equilibrium chamber 86 is allowed to change in volume. For example, the pressure-receiving chamber 84 and the equilibrium chamber 86 can be filled with a non-compressible fluid by performing the attachment work of the flexible membrane 34 and the partition member 40 to the second attachment member 14 in the non-compressible fluid.

[0049] By mounting the partition member 40 to the second mounting member 14, the opening of the circumferential groove 46 is fluid-tightly closed by the second mounting member 14 covered with the seal rubber layer 32, forming a flow passage extending in the circumferential direction. One end of this flow passage is connected to the pressure receiving chamber 84 through a first communication port 88 formed in the first partition plate 42, and the other end is connected to the equilibrium chamber 86 through a second communication port 90 formed in the second partition plate 44. As a result, an orifice passage 92 that connects the pressure receiving chamber 84 and the equilibrium chamber 86 to each other is formed by utilizing the circumferential groove 46. The orifice passage 92 is tuned to the resonant frequency of the flowing fluid to the frequency of the vibration to be damped by adjusting the ratio of the passage length to the passage cross-sectional area while taking into account the spring of the wall of the pressure receiving chamber 84, etc. In this embodiment, the tuning frequency of the orifice passage 92 is set to a low frequency of about 10 Hz, which corresponds to engine shake.

[0050] The accommodation cavity 66 of the partition member 40 is in communication with the pressure-receiving chamber 84 through the first central through hole 50 and the first outer peripheral through hole 52, and is also in communication with the equilibrium chamber 86 through the second central through hole 58 and the second outer peripheral through hole 60. The movable membrane 68 disposed in the accommodation cavity 66 is subjected to the liquid pressure of the pressure-receiving chamber 84 on its upper surface and the liquid pressure of the equilibrium chamber 86 on its lower surface. Therefore, when a relative internal pressure difference occurs between the pressure-receiving chamber 84 and the equilibrium chamber 86, a force acts in the vertical direction on the movable membrane 68, and the movable membrane 68 is deformed or displaced. The resonant frequency of the bending deformation of the movable membrane 68 is set to the frequency of the vibration to be damped, which is higher than the tuning frequency of the orifice passage 92, and the movable membrane 68 is actively deformed in a resonant state when the vibration to be damped is input.

[0051] A gap 80 provided on the outer periphery of the movable membrane 68 communicates with a pressure-receiving chamber 84 through a communication passage 82, the first central through hole 50, and the first outer periphery through hole 52.

[0052] Due to the seal structure formed by the abutment of the seal portion 72 of the movable membrane 68 with the second wall inner surface 65 of the accommodating cavity 66, the gap 80 is not in communication with the equilibrium chamber 86, and the pressure-receiving chamber 84 and the equilibrium chamber 86 are not in communication with each other via the accommodating cavity 66, but are blocked by the movable membrane 68. Note that the seal structure formed by the abutment of the seal portion 72 with the second wall inner surface 65 is not necessarily limited to one that completely blocks the flow of fluid, but may be one that prevents fluid flow to such an extent that it would cause a decrease in vibration-proofing performance when normal vibration is input.

[0053] The engine mount 10 constructed in this manner is mounted to a vehicle, for example, by attaching the first mounting member 12 to a power unit via an inner bracket (not shown) in which the first mounting member 12 is fitted into the bracket mounting portion 18, and by attaching the second mounting member 14 to the vehicle body via an outer bracket (not shown) to which the second mounting member 14 is fitted externally.

[0054] When engine mount 10 is attached to a vehicle, if low-frequency, large-amplitude vibrations equivalent to engine shake or the like are input in the vertical direction between first mounting member 12 and second mounting member 14, a change in internal pressure occurs in pressure-receiving chamber 84, part of whose wall is formed by main rubber elastic body 16. Then, based on the relative pressure difference between pressure-receiving chamber 84 and equilibrium chamber 86, fluid flow between pressure-receiving chamber 84 and equilibrium chamber 86 through orifice passage 92 actively occurs in a resonant state, and a vibration-proofing effect (vibration damping effect) is achieved based on the fluid flow action.

[0055] When low-frequency large-amplitude vibration is input, the deformation of the movable membrane 68 cannot follow the amplitude of the input vibration, and the movable membrane 68 is substantially constrained, so that the effect of absorbing the liquid pressure in the pressure-receiving chamber 84 due to the deformation of the movable membrane 68 is not fully exerted. Therefore, a large internal pressure difference is secured between the pressure-receiving chamber 84 and the equilibrium chamber 86, and fluid flow is efficiently generated through the orifice passage 92, so that the vibration-damping effect of the orifice passage 92 can be advantageously obtained. When the greatly deformed movable membrane 68 strikes the inner wall surfaces 55, 65 of the accommodation cavity 66 and is restrained, the minute buffer protrusions 78 protruding from both the front and back sides of the movable membrane 68 preferentially strike the inner wall surfaces 55, 65 of the accommodation cavity 66, thereby reducing the striking noise at the time of strike.

[0056] When medium to high frequency small amplitude vibrations corresponding to idling vibrations and the like that are higher than the tuning frequency of the orifice passage 92 are input, the orifice passage 92 is essentially blocked by anti-resonance. The movable membrane 68 actively flexes and deforms in a resonant state in response to the input vibration, absorbing the internal pressure fluctuations in the pressure-receiving chamber 84 caused by the vibration input. This prevents the pressure-receiving chamber 84 from becoming substantially sealed off, resulting in a significant high springiness, and provides a vibration-proofing effect (vibration isolation effect) by reducing the dynamic springiness.

[0057] When a vehicle travels over a step or the like and a vibration of extremely large amplitude is input, causing a significant drop in the internal pressure of the pressure-receiving chamber 84, a force acts on the movable membrane 68 toward the pressure-receiving chamber 84, that is, toward the upward direction, based on the relative internal pressure difference between the pressure-receiving chamber 84 and the equilibrium chamber 86. Due to the action of this force, as shown in Fig. 7, the elastic protrusion 70 of the movable membrane 68 is compressed and contracted in the vertical direction, the lower surface of the outer peripheral end of the movable membrane 68 is displaced upward, and the seal portion 72 provided on the outer peripheral end of the movable membrane 68 is separated upward, for example, over substantially the entire circumference in the circumferential direction, from the seal abutment portion 64 constituting the second wall inner surface 65 of the accommodation space 66. Particularly, in this embodiment, the elastic protrusion 70 is efficiently compressed and deformed in the vertical direction while deformation of the outer peripheral end of the movable membrane 68 other than the portion where the elastic protrusion 70 is formed is relatively suppressed. As a result, the seal portion 72 at the outer peripheral end of the movable membrane 68 is displaced upward over substantially the entire circumference in the circumferential direction, including the portion where the elastic protrusion 70 is formed, and is separated from the seal abutment portion 64. As a result, the gap 80 provided on the outer peripheral side of the movable membrane 68 is communicated with the equilibrium chamber 86 through the second outer peripheral through hole 60, and a relief passage 94 that communicates the pressure receiving chamber 84 and the equilibrium chamber 86 is formed by including the gap 80 and the communication passage 82. Then, the sealed fluid flows from the equilibrium chamber 86 to the pressure receiving chamber 84 through the relief passage 94, so that the internal pressure drop of the pressure receiving chamber 84 is quickly reduced or eliminated, and the occurrence of cavitation due to the internal pressure drop of the pressure receiving chamber 84 is prevented. As a result, the occurrence of abnormal noise and vibration due to cavitation is prevented, and the quietness and ride comfort of the vehicle are improved.

[0058] The relief passage 94 is provided so as to wrap around the outer peripheral end of the movable membrane 68, and therefore has a larger circumferential length and a larger passage cross-sectional area than when the relief passage 94 is provided in the central portion of the movable membrane as in the conventional structure. This increases the flow rate of the relief passage 94, allowing the enclosed fluid to flow quickly from the equilibrium chamber 86 to the pressure-receiving chamber 84, and quickly reducing the negative pressure in the pressure-receiving chamber 84. The relief passage 94 also has a shorter passage length than the orifice passage 92, and a larger ratio of the passage cross-sectional area to the passage length. The relief passage 94 has a smaller flow resistance than the orifice passage 92, and a larger flow rate is ensured.

[0059] Since the elastic protrusion 70 has a tapered shape, the spring becomes larger nonlinearly as the amount of compressive deformation increases, making it difficult for further compressive deformation to occur. Therefore, when the internal pressure of the pressure-receiving chamber 84 drops significantly, the elastic protrusion 70 is allowed to compressively deform to quickly open the relief passage 94, while preventing the elastic protrusion 70 from excessively collapsing and thus blocking the communication passage 82, thereby maintaining the communication state of the relief passage 94.

[0060] If vibrations of extremely large amplitude are input and the internal pressure of the pressure-receiving chamber 84 rises significantly, the seal portion 72 may be further compressed and the outer peripheral end of the movable membrane 68 may be displaced downward. In this case, even if the tip face of the elastic protrusion 70 separates from the first wall inner surface 55 of the accommodating space 66, the tapered spherical crown shape of the protruding tip face of the elastic protrusion 70 reduces the impact noise when it comes into contact with the first wall inner surface 55 again.

[0061] 8 shows an engine mount 100 for an automobile as a second embodiment of a fluid-filled type vibration damping device constructed in accordance with the present invention. In the following explanation, the same reference numerals are used in the drawings to designate the same members and parts as those in the first embodiment, and explanations thereof will be omitted.

[0062] The engine mount 100 has a structure in which a movable membrane 102 is disposed in the accommodation space 66 of a partition member 104. The movable membrane 102 does not have the elastic protrusion 70 shown in the first embodiment at its outer circumferential end, and the upper surface of the outer circumferential end is made flat.

[0063] The first partition plate 106 constituting the partition member 104 has a plurality of grooves 108 opening on the wall inner surface (first wall inner surface 55) of the accommodation cavity 66 on the pressure receiving chamber 84 side. The grooves 108 extend in the radial direction in the outer peripheral portion of the accommodation cavity 66, and the inner peripheral end portion opens to the first outer peripheral through hole 52. In other words, the wall inner surface (first wall inner surface 55) of the accommodation cavity 66 on the pressure receiving chamber 84 side has a plurality of ridges extending in the radial direction and protruding downward, and the grooves 108 opening relatively downward are formed between the circumferential spaces of the plurality of ridges. That is, the ridges are formed integrally with the first partition plate 106 and are hard ridges. The ridges may be elastic ridges, and for example, the plurality of grooves 108 may be formed by later fixing elastic ridges formed separately from the first partition plate 106.

[0064] The first wall inner surface 55 of the accommodating space 66, at a portion circumferentially outside the recessed groove 108, abuts against the upper surface of the outer circumferential end of the movable membrane 102. As a result, the outer circumferential end of the movable membrane 102 is vertically sandwiched by the partition member 104 at a portion circumferentially outside the recessed groove 108. Therefore, at the outer circumferential end of the movable membrane 102, the portion circumferentially outside the recessed groove 108 that abuts against the first partition plate 106 is defined as the abutment portion in this embodiment.

[0065] By disposing the movable membrane 102 in the accommodating space 66, the lower opening of the recessed groove 108 is covered by the movable membrane 102, and a radially extending communication passage 110 is formed by the recessed groove 108. The inner peripheral end of the communication passage 110 communicates with the pressure-receiving chamber 84 through the first outer peripheral through hole 52, and the outer peripheral end of the communication passage 110 communicates with the gap 80 provided on the outer peripheral side of the movable membrane 102.

[0066] In the engine mount 100 constructed according to this embodiment, as in the first embodiment, when the internal pressure of the pressure receiving chamber 84 drops significantly due to vibration input, the pressure receiving chamber 84 and the equilibrium chamber 86 communicate with each other through a relief passage (not shown) including the gap 80 and the communication passage 110. That is, when the internal pressure of the pressure receiving chamber 84 drops significantly, a force toward the pressure receiving chamber 84 acts on the movable membrane 102 due to the relative pressure difference between the pressure receiving chamber 84 and the equilibrium chamber 86, and the abutting portion of the outer circumferential end of the movable membrane 102 is compressed in the vertical direction. As a result, the outer circumferential end of the movable membrane 102 is displaced toward the pressure receiving chamber 84, and the seal portion 72 of the movable membrane 102 is separated from the seal abutting portion 64 that constitutes the wall inner surface (second wall inner surface 65) on the equilibrium chamber 86 side of the accommodation space 66. As a result, the gap 80, which is in communication with the pressure receiving chamber 84 through the communication passage 110, is in communication with the equilibrium chamber 86 through the gap between the seal portion 72 and the seal abutment portion 64 and the second outer peripheral through hole 60, and a relief passage connecting the pressure receiving chamber 84 and the equilibrium chamber 86 is formed by including the gap 80 and the communication passage 110. Then, the enclosed fluid flows from the equilibrium chamber 86 to the pressure receiving chamber 84 through the relief passage, thereby suppressing a drop in the internal pressure of the pressure receiving chamber 84 and preventing the occurrence of cavitation.

[0067] In the first embodiment, an elastic protrusion 70 was provided on the movable membrane 68, and an unevenness was provided at the overlapping portion of the outer circumferential portion of the movable membrane 68 with the first wall inner surface 55, thereby forming a contact portion with the communicating passage 82. However, as in the present embodiment, an unevenness can also be provided at the clamping portion of the movable membrane 102 in the partition member 104, thereby forming a contact portion with the communicating passage 110.

[0068] 9 shows a partition member 120 in an engine mount as a third embodiment of a fluid-filled type vibration damping device constructed according to the present invention. The structures of the fluid-filled type vibration damping device in this embodiment other than the partition member 120 are omitted from the illustration because the same structures as those in the first embodiment can be adopted. Although the shapes of the partition member 120 and the movable membrane 122 housed inside the partition member 120 are also similar to those of the partition member 40 and the movable membrane 68 in the first embodiment, the movable membrane 122 in this embodiment has different deformation rigidity at each portion, for example, compared to the movable membrane 68 in the first embodiment. As a result, in this embodiment, a relief passage 124 is formed in a manner different from that in the first embodiment.

[0069] Specifically, for example, in the first embodiment, by adjusting the material, size, and compression ratio of the movable membrane 68 and the elastic protrusion 70, etc., in the installed state, the elastic protrusion 70 easily undergoes compressive deformation, causing the entire outer circumferential end of the movable membrane 68 to rise from the seal abutment portion 64 and creating a relief passage 94, but in this embodiment, the elastic deformation characteristics of the movable membrane 122 including the elastic protrusion 126 are made different from those of the first embodiment.

[0070] In this embodiment, when a relative pressure difference is applied to both sides of the movable membrane 122, the elastic deformation is likely to occur as an elastic deformation in the bending direction of the surface of the movable membrane 122, and is unlikely to occur as a compressive deformation in the protruding direction of the elastic protrusion 126. Therefore, for example, when the internal pressure of the pressure-receiving chamber 84 is reduced, an upward force acts on the movable membrane 122 due to the relative internal pressure difference between the pressure-receiving chamber 84 and the equilibrium chamber 86, and as shown in FIG. 9, the part of the outer peripheral end of the movable membrane 122 where the elastic protrusion 126 is not provided (the intermediate part between the elastic protrusions 126, 126 adjacent in the circumferential direction, where the deformation restraining force by the elastic protrusion 126 is unlikely to be applied) is elastically bent and deformed so as to be lifted upward. FIG. 10 shows the movable membrane 122 in such a deformed state. Note that the buffer protrusions 78 are omitted from FIG. 10.

[0071] That is, as shown in Fig. 9, at the portion where the elastic protrusion 126 is formed at the outer peripheral end of the movable membrane 122, the elastic protrusion 126 abuts against the wall inner surface (first wall inner surface 55) on the pressure receiving chamber 84 side of the accommodation cavity 66, and the seal portion 72 abuts against the wall inner surface (second wall inner surface 65) on the equilibrium chamber 86 side of the accommodation cavity 66 (see the right side of Fig. 9). On the other hand, as also shown in Fig. 10, the circumferential space between the elastic protrusions 126, 126 at the outer peripheral end of the movable membrane 122 deforms so that the seal portion 72 is separated upward from the wall inner surface (second wall inner surface 65) on the equilibrium chamber 86 side of the accommodation cavity 66. In this way, by providing an upwardly deformed portion 128 between the elastic protrusions 126, 126 at the outer peripheral end of the movable membrane 122 in the circumferential direction, a raised portion 130 that rises from the second wall inner surface 65 is provided at the circumferential position of the seal portion 72 corresponding to the deformed portion 128. At the position where the raised portion 130 is formed, the seal portion 72 is released from contact with the seal contact portion 64 , and the gap 80 and the equilibrium chamber 86 are connected through the gap created by the raised portion 130 .

[0072] In this manner, in this embodiment, the gap communicating between the gap 80 and the equilibrium chamber 86 is provided at the same circumferential position as the circumferential space between the elastic protrusions 126, 126, and is provided intermittently all around the circumference. This allows the pressure-receiving chamber 84 and the equilibrium chamber 86 to communicate with each other through the relief passage 124, which is constituted by the gap 80 and the communication passage 82, thereby preventing the occurrence of cavitation.

[0073] The engine mount of this embodiment having the partition member 120 of the above-described structure can also achieve the same effects as those of the first embodiment. In particular, unlike the first embodiment, even if the deformation rigidity of the elastic protrusion 126 is relatively large compared to the movable membrane 122, the circumferential space (deformed portion 128) between the elastic protrusions 126, 126 at the outer circumferential end portion of the movable membrane 122 can be deformed to generate a raised portion 130 in the seal portion 72, thereby making the relief passage 124 communicated.

[0074] Although the embodiment of the present invention has been described in detail above, the present invention is not limited to the specific description. For example, the elastic protrusion 70 may have a certain length in the circumferential direction, and may be shaped to extend continuously in the circumferential direction for a predetermined length. Also, for example, a plurality of partial grooves may be formed in the annular protrusion in the circumferential direction, and the elastic protrusion may be formed between the grooves in the circumferential direction.

[0075] The through-hole connecting the pressure-receiving chamber 84 and the accommodating cavity 66 does not have to include the first central through-hole 50 and the first outer peripheral through-hole 52, and may, for example, include only the first outer peripheral through-hole 52. The through-hole connecting the equilibrium chamber 86 and the accommodating cavity 66 does not have to include the second central through-hole 58 and the second outer peripheral through-hole 60, and may, for example, include only the second outer peripheral through-hole 60.

[0076] The specific sealing structure by pressing the seal portion against the seal abutment portion is not particularly limited as long as the structure is such that the space between the seal portion and the seal abutment portion is sealed fluid-tight. Specifically, for example, the abutment surface of the seal portion against the seal abutment portion may be a flat surface, and the space between the seal portion and the seal abutment portion may be sealed by pressing a seal protrusion that protrudes from the seal abutment portion continuously in the circumferential direction against the flat surface of the seal portion. In addition, as long as fluid-tightness can be ensured, the abutment surfaces of both the seal portion and the seal abutment portion may be flat surfaces.

[0077] In addition, the part of the movable membrane that deforms and the specific deformation mode are not limited, and for example, the central part of the movable membrane may deform and the deformation may propagate to the outer peripheral end, so that the seal part at the outer peripheral end of the movable membrane is separated from the seal abutment part of the second partition plate, and the pressure-receiving chamber and the equilibrium chamber are communicated by the relief passage. In the fluid-filled vibration-damping device according to the present invention, the deformation rigidity of the movable membrane and the elastic protrusion, including the size and shape, are not limited, and the deformation mode of the movable membrane and the elastic protrusion when the internal pressure of the pressure-receiving chamber decreases is also not limited. Therefore, the shape of the movable membrane can be designed arbitrarily according to the desired vibration-damping characteristics, and the present invention can provide a fluid-filled vibration-damping device with a high degree of design freedom.

[0078] In the third embodiment, when the internal pressure of the pressure-receiving chamber 84 decreases and an upward force acts on the movable membrane 68, not only the deformed portion 128 but also the elastic protrusion 126 may be pressed against the first partition plate 42, and thus be sufficiently compressed in the vertical direction. The gap between the seal portion 72 and the seal abutment portion 64 may have an annular portion extending around the entire circumferential direction, while the vertical dimension of the gap becomes larger at the position where the raised portion 130 is formed (approximately the center between adjacent elastic protrusions 126, 126 in the circumferential direction), thus combining the first and third embodiments (in which the size of the gap changes in the circumferential direction) may be adopted. Furthermore, the present invention essentially includes each of the inventions described in (i) to (vii) below, and the configurations and effects thereof will be described below. The present invention relates to (i) A fluid-filled vibration-damping device in which a pressure-receiving chamber and an equilibrium chamber are separated by a partition member, and a movable membrane is accommodated in an accommodation cavity formed in the partition member, the outer peripheral end of the movable membrane has an abutment portion that abuts partially in the circumferential direction against the inner wall surface of the accommodation cavity on the pressure-receiving chamber side, and a seal portion that abuts over the entire circumference against the inner wall surface of the accommodation cavity on the equilibrium chamber side, the outer peripheral end of the movable membrane is supported by the partition member, a gap is provided between the opposing outer peripheral surface of the movable membrane and the inner peripheral surface of the accommodation cavity, and a communication passage that communicates with the gap is provided at a position of the outer peripheral end of the movable membrane away from the corresponding contact portion with the inner wall surface of the accommodation cavity on the pressure-receiving chamber side, and a relief passage communicating between the pressure-receiving chamber and the equilibrium chamber is configured to include the gap and the communication passage when the outer peripheral end of the movable membrane moves away from the inner wall surface of the accommodation cavity on the equilibrium chamber side due to a pressure difference between the pressure-receiving chamber and the equilibrium chamber; (ii) a fluid-filled vibration-damping device according to (i), in which a plurality of elastic protrusions protruding toward the pressure-receiving chamber are provided in the circumferential direction on the outer peripheral end of the movable membrane, the elastic protrusions abut against the inner wall surface of the accommodating space on the pressure-receiving chamber side of the partition member to form a contact portion, and the communication passage is formed between the plurality of elastic protrusions in the circumferential direction; (iii) A fluid-filled vibration-damping device as described in (ii), in which the action of a pressure difference between the pressure-receiving chamber and the equilibrium chamber on the movable membrane causes the seal portion at the outer peripheral end of the movable membrane to separate from the inner wall surface of the accommodating space on the equilibrium chamber side between the circumferential direction of the elastic protrusions, and the relief passage is generated at the formation portion of the elastic protrusions while maintaining the respective abutment states between the inner wall surface of the accommodating space on the pressure-receiving chamber side and the elastic protrusions, and between the inner wall surface of the accommodating space on the equilibrium chamber side and the seal portion. (iv) A fluid-filled vibration-damping device according to (ii) or (iii), in which the elastic protrusion has a tapered shape that contracts toward the protruding tip. (v) A fluid-filled vibration-damping device according to any one of (ii) to (iv), in which the protruding tip surface of the elastic protrusion is a spherical crown-shaped curved surface. (vi) A fluid-filled vibration-damping device according to any one of (i) to (v), wherein the partition member is provided with a plurality of grooves opening into an outer circumferential portion of the inner wall surface of the accommodating space on the side of the pressure-receiving chamber, the outer circumferential end of the movable membrane and the inner wall surface of the accommodating space on the side of the pressure-receiving chamber are in contact with each other at portions circumferentially offset from the grooves, and the communication passage is constituted by the grooves; (vii) A fluid-filled vibration-damping device according to any one of (i) to (vi), wherein an outer peripheral end of the movable membrane is provided with a seal lip that protrudes toward the equilibrium chamber and is continuous over the entire circumference, and the seal lip abuts against the inner wall surface of the accommodation space on the equilibrium chamber side over the entire circumference. This includes inventions relating to. In the invention described in (i) above, a relief passage is formed that opens when the internal pressure of the pressure receiving chamber drops, and communicates the pressure receiving chamber and the equilibrium chamber with each other. As a result, the internal pressure drop of the pressure receiving chamber is quickly reduced by the inflow of fluid from the equilibrium chamber to the pressure receiving chamber through the relief passage, and the occurrence of cavitation due to a significant internal pressure drop of the pressure receiving chamber is prevented, and abnormal noise and the like associated with cavitation is prevented. The relief passage is configured to include a communication passage extending between the outer peripheral end of the movable membrane and the inner wall surface of the accommodation cavity on the pressure receiving chamber side, and a gap formed between the outer peripheral surface of the movable membrane and the inner peripheral surface of the accommodation cavity, and is located at the outer periphery of the accommodation cavity. Therefore, the relief passage can be easily set to have a long circumferential length without requiring an increase in the size of the fluid-filled vibration damping device, and a large passage cross-sectional area can be ensured. As a result, the internal pressure drop of the pressure receiving chamber can be quickly eliminated by the fluid flow through the relief passage, and cavitation can be effectively prevented. Under normal vibration input conditions where cavitation is not an issue, the seal portion of the movable membrane abuts against the inner wall surface of the accommodating cavity on the equilibrium chamber side, closing the relief passage and preventing short-circuiting between the pressure-receiving chamber and the equilibrium chamber through the relief passage. Therefore, during normal vibration input, internal pressure fluctuations in the pressure-receiving chamber are efficiently induced, and vibration-damping effects due to the flow action of the fluid and the liquid pressure absorption action of the movable membrane are effectively demonstrated. In the invention described in (ii) above, since the abutting portion is an elastic protrusion, depending on, for example, the deformation rigidity of the elastic protrusion and the movable membrane, the compression of the elastic protrusion allows the outer peripheral end of the movable membrane to be displaced toward the pressure-receiving chamber, and, for example, the seal portion can be separated from the inner wall surface of the accommodating space on the equilibrium chamber side over substantially the entire circumference in the circumferential direction to form a relief passage. Since a plurality of elastic protrusions are provided in the circumferential direction of the movable membrane, for example, the spring constant of the elastic protrusions can be adjusted by the circumferential width dimension or interval of the elastic protrusions, and a threshold value of the internal pressure drop in the pressure-receiving chamber at which the relief passage is opened can be set. In the invention described in (iii) above, depending on, for example, the deformation rigidity of the elastic protrusions and the movable membrane, when the internal pressure of the pressure-receiving chamber is reduced, the elastic protrusions and the seal parts maintain their respective contact states with the inner wall surfaces of the accommodating space on the pressure-receiving chamber side and the equilibrium chamber side at the outer peripheral end of the movable membrane where the elastic protrusions are formed, while the seal parts are separated from the inner wall surface on the equilibrium chamber side at the circumferential direction between the elastic protrusions at the outer peripheral end of the movable membrane, thereby forming a relief passage. That is, depending on, for example, the deformation rigidity of the elastic protrusions and the movable membrane, it is possible to form a relief passage by separating the seal parts from the inner wall surface on the equilibrium chamber side over substantially the entire circumference as in the first embodiment described later, or to form a relief passage by separating the seal parts from the inner wall surface on the equilibrium chamber side between the elastic protrusions in the circumferential direction as in this embodiment and the third embodiment described later. In short, for example, even in the fluid-filled vibration-damping device according to the second embodiment, a relief passage can be formed in an appropriate manner depending on, for example, the deformation rigidity of the elastic protrusions and the movable membrane, and the degree of freedom in designing the elastic protrusions, the movable membrane, and ultimately the fluid-filled vibration-damping device is improved. In the invention described in (iv) above, the change in spring constant due to compression of the elastic protrusion can be made nonlinear, so that when the internal pressure of the pressure-receiving chamber drops significantly, the elastic protrusion is prevented from being completely crushed, thereby preventing the communication passage from being blocked, and preventing unintended blocking of the relief passage. In the invention described in (v) above, when the abutment portion is pressed against the inner wall surface of the accommodating cavity on the pressure-receiving chamber side, stress concentration on the surface of the abutment portion is avoided, improving the durability of the abutment portion. Also, for example, when a large positive pressure acts on the pressure-receiving chamber, causing the abutment portion of the movable membrane to move away from the inner wall surface of the accommodating cavity on the pressure-receiving chamber side, and then the abutment portion abuts against the inner wall surface of the accommodating cavity on the pressure-receiving chamber side due to the release of the positive pressure, the hitting noise is reduced. In the invention described in (vi) above, by forming a groove on the inner wall surface of the accommodating cavity on the pressure-receiving chamber side, it is possible to form a communication passage by the groove at a position away from the abutment part without providing a protrusion or the like on the outer peripheral end of the movable membrane. When the internal pressure of the pressure-receiving chamber decreases, the abutment part of the movable membrane is pressed against the inner wall surface of the accommodating cavity on the pressure-receiving chamber side at a position away from the groove and compressed, allowing the outer peripheral end of the movable membrane to displace toward the pressure-receiving chamber, and the seal part is separated from the inner wall surface of the accommodating cavity on the equilibrium chamber side to form a relief passage. In the invention described in (vii) above, the sealing portion is provided with a sealing lip, and thereby the sealing portion abuts against the inner wall surface on the equilibrium chamber side of the accommodating space, thereby improving the sealing performance and improving the vibration-damping performance against the input of normal vibrations. [Explanation of symbols]

[0079] 10 Engine mount (fluid-filled vibration isolation device, first embodiment) 12 First mounting member 14 Second mounting member 16 Main rubber elastic body 18 Bracket attachment part 20 Fixing part 22 Large diameter cylinder 24 Small diameter cylinder part 26 Recess 28 Stopper rubber 30 Fitting rubber 32 Sealing rubber layer 34 Flexible membrane 36 Fixing member 38 Fluid chamber 40 Partitioning member 42 First Partition 44 Second Partition 46 Circumferential groove 48 Central recess 50 First central hole 52 First outer peripheral hole 54 Recessed portion 55 First wall inside 56 First constriction 58 Second central hole 60 Second outer peripheral hole 62 Second constriction 64 Seal contact part 65 Second wall inner surface 66 Vacant accommodation space 68 Movable Membrane 70 Elastic protrusion (contact part) 72 Seal part 74 Outer lip (seal lip) 76 Inner lip (seal lip) 78 Buffer protrusion 80 Gap 82 Communication path 84 Pressure Room 86 Equilibrium chamber 88 First communication port 90 Second communication port 92 Orifice passage 94 Relief Passage 100 Engine mount (fluid-filled vibration isolation device, second embodiment) 102 Movable membrane 104 Partitioning member 106 First Partition 108 Groove 110 Communication path 120 Partition member (third embodiment) 122 Movable membrane 124 Relief Passage 126 Elastic protrusion 128 Transformation Part 130 Raised part

Claims

1. A fluid-filled vibration-damping device in which a pressure-receiving chamber and an equilibrium chamber are separated by a partition member, and a movable membrane is accommodated in an accommodation space formed in the partition member, an outer peripheral end portion of the movable membrane includes an abutment portion that is partially in circumferential contact with an inner wall surface of the storage space on the pressure-receiving chamber side, and a seal portion that is in circumferential contact with an inner wall surface of the storage space on the equilibrium chamber side, The outer peripheral end of the movable film is supported by the partition member, A gap is provided between the outer circumferential surface of the movable film and the inner circumferential surface of the accommodation space, a communication passage communicating with the gap is provided at a position at an outer peripheral end of the movable membrane away from a corresponding contact portion with the inner wall surface of the accommodating space on the pressure-receiving chamber side, The outer peripheral end of the movable membrane is separated from the inner wall surface of the accommodating space on the side of the equilibrium chamber due to the pressure difference between the pressure-receiving chamber and the equilibrium chamber, thereby forming a relief passage connecting the pressure-receiving chamber and the equilibrium chamber, the relief passage including the gap and the communication passage. A plurality of elastic protrusions protruding toward the pressure-receiving chamber are provided in a circumferential direction on an outer peripheral end of the movable film, the elastic protrusion abuts against an inner wall surface of the partition member on the pressure-receiving chamber side of the accommodating space to form an abutment portion, The communication passage is formed between the elastic protrusions in the circumferential direction, A fluid-filled vibration-damping device in which the action of the pressure difference between the pressure-receiving chamber and the equilibrium chamber on the movable membrane causes the sealing portion at the outer peripheral end of the movable membrane to move away from the inner wall surface on the equilibrium chamber side of the accommodating space between the circumferential direction of the elastic protrusions, and the relief passage is manifested at the location where the elastic protrusions are formed, while maintaining the respective abutment states between the inner wall surface on the pressure-receiving chamber side of the accommodating space and the elastic protrusions, and between the inner wall surface on the equilibrium chamber side and the sealing portion.

2. 2. A fluid-filled vibration-damping device according to claim 1, wherein the elastic projection has a tapered shape that contracts toward the protruding tip.

3. 3. A fluid-filled vibration-damping device according to claim 1, wherein the protruding tip surface of said elastic projection is formed into a spherical crown-shaped curved surface.

4. A fluid-filled vibration-proof device, in which a pressure-receiving chamber and an equilibrium chamber are separated by a partition member, and a movable membrane is accommodated in an accommodation space formed in the partition member, an outer peripheral end portion of the movable membrane includes an abutment portion that is partially in circumferential contact with an inner wall surface of the storage space on the pressure-receiving chamber side, and a seal portion that is in circumferential contact with an inner wall surface of the storage space on the equilibrium chamber side, The outer peripheral end of the movable film is supported by the partition member, A gap is provided between the outer circumferential surface of the movable film and the inner circumferential surface of the accommodation space, a communication passage communicating with the gap is provided at a position at an outer peripheral end of the movable membrane away from a corresponding contact portion with the inner wall surface of the accommodating space on the pressure-receiving chamber side, The outer peripheral end of the movable membrane is separated from the inner wall surface of the accommodating space on the side of the equilibrium chamber due to the pressure difference between the pressure-receiving chamber and the equilibrium chamber, thereby forming a relief passage connecting the pressure-receiving chamber and the equilibrium chamber, the relief passage including the gap and the communication passage. The partition member has a plurality of grooves that open to an outer circumferential portion of an inner wall surface of the accommodating space on the side of the pressure receiving chamber, The outer peripheral end of the movable membrane and the inner wall surface of the accommodating space on the side of the pressure-receiving chamber are in contact with each other at a portion that is out of the groove in the circumferential direction, The fluid-filled vibration-damping device, wherein the communication passage is constituted by the groove.

5. the outer peripheral end of the movable membrane is provided with a seal lip that protrudes toward the equilibrium chamber and is continuous around the entire circumference, 5. The fluid-filled vibration-damping device according to claim 1, wherein the seal lip is in contact with the inner wall surface of the accommodating space on the equilibrium chamber side over the entire periphery.

6. A fluid-filled vibration-proof device, in which a pressure-receiving chamber and an equilibrium chamber are separated by a partition member, and a movable membrane is accommodated in an accommodation space formed in the partition member, an outer peripheral end portion of the movable membrane includes an abutment portion that is partially in circumferential contact with an inner wall surface of the storage space on the pressure-receiving chamber side, and a seal portion that is in circumferential contact with an inner wall surface of the storage space on the equilibrium chamber side, The outer peripheral end of the movable film is supported by the partition member, A gap is provided between the outer circumferential surface of the movable film and the inner circumferential surface of the accommodation space, a communication passage is provided between an opposing surface of an inner wall surface of the accommodating space on the pressure-receiving chamber side and a surface of the movable membrane on the pressure-receiving chamber side at an outer peripheral end of the movable membrane, the communication passage being connected to the gap at a position circumferentially separated from a corresponding contact portion with the inner wall surface on the pressure-receiving chamber side, When the outer peripheral end of the movable membrane is separated from the inner wall surface of the accommodating space on the side of the equilibrium chamber due to the pressure difference between the pressure-receiving chamber and the equilibrium chamber, a relief passage communicating between the pressure-receiving chamber and the equilibrium chamber is formed including the gap and the communication passage, In the fluid-filled vibration-damping device, an orifice passage is provided in the outer circumferential portion of the partition member, which extends circumferentially on the outer circumferential side of the relief passage and connects the pressure-receiving chamber and the equilibrium chamber.

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