JP7630390B2 - Fluid-filled vibration isolation device - Google Patents

Description

The present invention relates to a fluid-filled vibration isolation device used in automobile engine mounts, etc.

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

However, with fluid-filled vibration isolation devices, the generation of abnormal noises 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 into the main liquid chamber, relieving the negative pressure in the main liquid chamber and suppressing cavitation.

JP 2013-231480 A

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 also difficult to increase the cross-sectional area of the relief passage, which can be switched between open and closed by the relief valve. As a result, Patent Document 1 has revealed a new problem in that even when 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.

The problem to be solved by this invention is to provide a fluid-filled vibration isolation device with a new structure that can effectively suppress cavitation.

The following describes preferred embodiments for understanding the present invention. However, each embodiment described below is merely an example, and may be combined with one another as appropriate. 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 alternative embodiments may be realized.

In a first aspect, 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, and an 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 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, The relief passage connecting the pressure-receiving chamber and the equilibrium chamber is composed of the gap and the communicating passage , while the outer peripheral end of the movable membrane is provided with a plurality of elastic protrusions in the circumferential direction protruding toward the pressure-receiving chamber, and the elastic protrusions abut against the inner wall surface on the pressure-receiving chamber side of the accommodating cavity in the partition member to form an abutment portion, and the communicating passage is formed between the circumferential direction of the plurality of elastic protrusions, and due to the action of the pressure difference between the pressure-receiving chamber and the equilibrium chamber on the movable membrane, the sealing portion at the outer peripheral end of the movable membrane moves away from the inner wall surface on the equilibrium chamber side of the accommodating cavity between the circumferential direction of the elastic protrusions, and the relief passage is manifested 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 accommodating cavity in the accommodating cavity, and between the sealing portion and the inner wall surface on the equilibrium chamber side .

A fluid-filled vibration-damping device constructed according to this embodiment has a relief passage that 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 cavitation caused by a significant drop in the internal pressure of the pressure-receiving chamber and preventing abnormal noise and other issues associated with cavitation.

The relief passage is located on the outer periphery of the accommodating cavity and includes a communication passage extending between the outer periphery of the movable membrane and the inner wall surface of the accommodating 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 accommodating cavity. Therefore, the relief passage can be easily set to a long circumferential length without requiring an increase in 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 in 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.
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.

In a second aspect, in the fluid-filled type vibration-damping device described in the first aspect, the elastic projection has a tapered shape that contracts toward the projection tip.

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. Therefore, 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.

In a third aspect, in the fluid-filled type vibration-damping device according to the first or second aspect, the protruding tip surface of the elastic projection is formed into a spherical crown-shaped curved surface.

With a fluid-filled vibration-damping device constructed according to this embodiment, when the abutment portion is pressed against the inner wall surface on the pressure-receiving chamber side of the accommodation cavity, stress concentration on the surface of the abutment portion is avoided, improving the durability of the abutment portion. In addition, 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 on the pressure-receiving chamber side of the accommodation cavity, and then the release of the positive pressure causes the abutment portion to abut against the inner wall surface on the pressure-receiving chamber side of the accommodation cavity, the impact noise is reduced.

A fourth 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 the circumferential direction against the inner wall surface of the accommodation space on the pressure-receiving chamber side, and a seal portion that abuts over the entire circumference against the 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 supported by the partition member, and a gap is provided between the opposing outer peripheral surface of the movable membrane and the inner peripheral surface of the accommodation space, and a communicating passage connected to the gap is provided at a position away from the corresponding contact portion, and the outer peripheral end of the movable membrane moves away from the inner wall surface of the storage cavity on the equilibrium chamber side 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, which includes the gap and the communicating passage, while the partition member has a plurality of grooves opening into the outer peripheral portion of the inner wall surface on the pressure-receiving chamber side of the storage cavity, and the outer peripheral end of the movable membrane and the inner wall surface on the pressure-receiving chamber side of the storage cavity abut at portions circumferentially away from the grooves, and the communicating passage is formed by the grooves.

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.
Furthermore, with a fluid-filled vibration-damping device constructed according to this embodiment, by forming a groove on the inner wall surface on the pressure-receiving chamber side of the accommodation cavity, 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 on the pressure-receiving chamber side of the accommodation recess 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 on the equilibrium chamber side of the accommodation cavity, forming a relief passage.

In a fifth aspect, in the fluid-filled vibration damping device according to any one of the first to fourth aspects, the seal portion has a seal lip that protrudes toward the equilibrium chamber and is continuous over the entire circumference, and the seal lip abuts the inner wall surface of the accommodation cavity on the equilibrium chamber side over the entire circumference. In addition, 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 circumference, and the seal lip abuts the inner wall surface of the accommodation cavity on the equilibrium chamber side over the entire circumference.

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.

The present invention makes it possible to effectively suppress cavitation.

FIG. 4 is a cross-sectional view showing an engine mount according to a first embodiment of the present invention, which corresponds to the cross-section II in FIG. FIG. 2 is a perspective view of a partition member constituting the engine mount shown in FIG. 1 ; FIG. 3 is a plan view of the partition member shown in FIG. FIG. 2 is a perspective view of a movable membrane constituting the engine mount shown in FIG. 1 . FIG. 5 is a perspective view showing the movable membrane of FIG. 4 from a different angle; 5 is a cross-sectional view of the movable membrane shown in FIG. FIG. 2 is a cross-sectional view of the engine mount shown in FIG. 1, showing a communication state of the relief passage; FIG. 1 is a cross-sectional view showing an engine mount according to a second embodiment of the present invention; FIG. 8 is a cross-sectional view corresponding to FIG. 7 (corresponding to the II cross section of 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; 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.

The following describes an embodiment of the present invention with reference to the drawings.

Figure 1 shows an engine mount 10 for an automobile as a first embodiment of a fluid-filled 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 description, the up-down direction generally refers to the up-down direction in Figure 1, which is the mount axial direction.

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

The second mounting member 14 has a stepped, generally cylindrical shape, with an upper portion being a large-diameter cylindrical portion 22 and a lower portion being 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 on generally 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.

The main rubber elastic body 16 is generally frusto-conical in shape, with the upper portion, which is the smaller diameter side, being vulcanized and bonded to the fastening portion 20 of the first mounting member 12, and the outer peripheral surface of the lower portion, which is the larger diameter side, being vulcanized and bonded to the large diameter tubular portion 22 of the second mounting member 14. The main rubber elastic body 16 has a recess 26 that opens to the underside and becomes smaller in diameter toward the top. The recess 26 is located below the fastening portion 20 of the first mounting member 12 and is located more inward than the small diameter tubular portion 24 of the second mounting member 14.

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

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 that has slack in the vertical direction. A ring-shaped fixing member 36 is fixed to the outer peripheral 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 circumference 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, a seal rubber layer 32 is interposed between the small diameter cylindrical portion 24 of the second mounting member 14 and the fixing member 36, so that the gap between the second mounting member 14 and the fixing member 36 is fluid-tight.

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. The fluid chamber 38 is filled with a non-compressible fluid. The non-compressible fluid is not particularly limited, but may be, for example, water, ethylene glycol, alkylene glycol, polyalkylene glycol, silicone oil, or a mixture thereof.

A partition member 40 is disposed in the fluid chamber 38. As shown in Figures 2 and 3, the partition member 40 is generally disk-shaped and has a first partition plate 42 and a second partition plate 44.

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 in the central portion 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 in the bottom wall of the central recess 48. A circular storage recess 54 is formed in the central portion of the first partition plate 42, opening on the lower surface. The storage recess 54 has a larger diameter and a shallower bottom than the central recess 48, and the outer peripheral end of the storage recess 54 is located on the outer periphery of the central recess 48. The first wall inner surface 55, which is the inner surface of the upper bottom wall of the storage 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 by passing through the common portion of the bottom wall portions of the central recess 48 and the storage recess 54, connecting the central recess 48 and the storage recess 54.

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 that is thinner than the first partition plate 42. A second central through hole 58 with a circular cross section that penetrates in the vertical direction is formed in the center of the second partition plate 44. A plurality of second outer peripheral through holes 60 that penetrate 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 that protrudes 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 vertical direction in the partition member 40.

The first partition plate 42 and the second partition plate 44 are overlapped with each other in the up-down direction. By overlapping the second partition plate 44 on the lower surface of the first partition plate 42, the opening of the accommodation recess 54 of the first partition plate 42 is covered by the second partition plate 44, and an accommodation space 66 is formed between the first partition plate 42 and the second partition plate 44. An upper wall inner surface of the accommodation space 66 that faces a pressure-receiving chamber 84 (described later) is formed by a first wall inner surface 55 of the first partition plate 42, and a lower wall inner surface of the accommodation space 66 that faces an equilibrium chamber 86 (described later) is formed by a 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 disposed 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 disposed at positions corresponding to each other in the up-down direction.

A movable membrane 68 is disposed in the accommodation space 66 of the partition member 40. As shown in Figs. 4 and 5, the movable membrane 68 has an overall disk shape. The movable membrane 68 is formed from 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 protrusion 70 described below, the movable membrane 68 may be partially or entirely embedded with a hard plate of, for example, metal or resin, to adjust its partial or overall deformation characteristics.

The movable membrane 68 has an elastic protrusion 70 integrally formed at its outer peripheral end, which protrudes upward. The elastic protrusion 70 protrudes from the outer peripheral end of the movable membrane 68 toward the pressure-receiving chamber 84 (described later) in the upward direction. A plurality of elastic protrusions 70 are provided, spaced apart from each other in the circumferential direction. The elastic protrusions 70 have an approximately circular cross section. The elastic protrusions 70 are tapered so that they 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 that is 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 approximately equal intervals in the circumferential direction.

A seal portion 72 is provided at the outer peripheral end of the movable membrane 68. The seal portion 72 is the lower end portion at the outer peripheral end of the movable membrane 68, and in this embodiment, it has 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 the equilibrium chamber 86 described below, and is an annular shape that extends continuously in the circumferential direction. The inner peripheral lip 76 protrudes downward on the inner circumference than the outer peripheral lip 74, and is an annular shape that extends in the circumferential direction in parallel with the outer peripheral lip 74.

A number of buffer protrusions 78 are provided on both the upper and lower surfaces of the inner periphery of the movable membrane 68. The buffer protrusions 78 are generally hemispherical in shape. The protruding height and width of the buffer protrusions 78 are smaller than those of the elastic protrusions 70. As shown in Figures 4 to 6, the buffer protrusions 78 in this embodiment are minute protrusions, and multiple ones are arranged in a generally cross shape.

As shown in FIG. 1, the movable membrane 68 is disposed in the accommodation space 66 of the partition member 40. The outer peripheral end of the movable membrane 68, which is provided with an elastic protrusion 70 and a seal portion 72, 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 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 pressed against the first wall inner surface 55 of the first partition plate 42 and the seal portion 72 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.

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 around the entire circumference in the circumferential direction, but as long as the relief passage including the gap sufficiently prevents the occurrence of cavitation 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.

When 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. The gap between the elastic protrusions 70, 70 forms a communication passage 82 that extends between the movable membrane 68 and the partition member 40 and communicates with the gap 80. In this embodiment, multiple 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 multiple 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 the 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 away from the elastic protrusion 70. Therefore, the contact portion that contacts the wall inner surface 55 of the housing cavity 66 on the pressure-receiving chamber 84 side is formed by the elastic protrusion 70, and is provided partially in the circumferential direction. In other words, in this embodiment, a communication passage 82 that communicates with the gap 80 is provided at a position circumferentially away from the elastic protrusion 70, which is the contact portion, at the outer circumferential end of the movable membrane 68.

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 forms 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 has an outer peripheral lip 74 and an inner peripheral lip 76, and a double seal structure is provided by pressing both the outer peripheral lip 74 and the inner peripheral lip 76 against the second partition plate 44. However, a seal structure using one seal lip or a multiple seal structure using three or more seal lips may also be used. Also, the seal lip may not be necessary.

In this way, 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 accommodation space 66.

As shown in FIG. 1, the partition member 40 containing the movable membrane 68 is disposed in the fluid chamber 38. 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 a seal rubber layer 32, so that the overlapping surfaces of the partition member 40 and the second mounting member 14 are sealed fluid-tight. The method of fixing the second mounting member 14 and the partition member 40 is not particularly limited, but for example, the partition member 40 is inserted into the inner circumference of the second mounting member 14, the second mounting member 14 is subjected to a diameter reduction process, and the inner peripheral surface of the second mounting member 14 and the outer peripheral surface of the partition member 40 are pressed against each other via the seal rubber layer 32 to be fixed. Furthermore, by reducing the diameter of the second mounting member 14, the precompression 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.

The fluid chamber 38 is divided into two by the partition member 40, and a pressure-receiving chamber 84 and an equilibrium chamber 86 are defined. That is, the upper side of the partition member 40 in the fluid chamber 38 is the pressure-receiving chamber 84, whose wall 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, whose wall 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 undergoes internal pressure fluctuations upon vibration input, while the equilibrium chamber 86 is allowed to change in volume. For example, the installation work of the flexible membrane 34 and the partition member 40 to the second mounting member 14 can be performed in a non-compressible fluid to fill the pressure-receiving chamber 84 and the equilibrium chamber 86.

When the partition member 40 is attached to the second mounting member 14, the opening of the circumferential groove 46 is fluid-tightly blocked by the second mounting member 14 covered with the seal rubber layer 32, forming a flow path extending in the circumferential direction. One end of this flow path 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 using the circumferential groove 46. The orifice passage 92 is tuned to the frequency of the vibration to be damped by adjusting the ratio of the passage length and the passage cross-sectional area while taking into account the spring of the wall of the pressure receiving chamber 84. 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.

The accommodation cavity 66 of the partition member 40 is connected to the pressure-receiving chamber 84 through the first central through hole 50 and the first outer peripheral through hole 52, and is connected to the equilibrium chamber 86 through the second central through hole 58 and the second outer peripheral through hole 60. The movable membrane 68 arranged in the accommodation cavity 66 is subjected to the liquid pressure of the pressure-receiving chamber 84 on the upper surface and the liquid pressure of the equilibrium chamber 86 on the 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 is actively deformed in a resonant state when the vibration to be damped is input.

The gap 80 provided on the outer periphery of the movable membrane 68 is connected to the pressure-receiving chamber 84 through the communication passage 82, the first central through hole 50, and the first outer peripheral through hole 52.

The gap 80 is not connected to the equilibrium chamber 86 due to the sealing structure formed by the contact between the seal portion 72 of the movable membrane 68 and the second wall inner surface 65 of the accommodation cavity 66, and the pressure-receiving chamber 84 and the equilibrium chamber 86 are not connected to each other via the accommodation cavity 66, but are blocked by the movable membrane 68. Note that the sealing structure formed by the contact between the seal portion 72 and 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 during normal vibration input.

The engine mount 10 constructed in this manner is attached to the vehicle, for example, by attaching the first mounting member 12 to the power unit via an inner bracket (not shown) that fits into the bracket mounting portion 18, and by attaching the second mounting member 14 to the vehicle body via an outer bracket (not shown) that fits over the outside.

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

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 essentially 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 ensured between the pressure-receiving chamber 84 and the equilibrium chamber 86, and fluid flow occurs efficiently through the orifice passage 92, and the vibration-damping effect of the orifice passage 92 can be advantageously obtained. In addition, 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, reducing the striking sound at the time of strike.

When medium to high-frequency small-amplitude vibrations equivalent 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 and becomes a highly springy structure, and provides a vibration-proofing effect (vibration isolation effect) by reducing the dynamic springiness.

When a vehicle goes over a step while traveling and a vibration of a significantly large amplitude is input, the internal pressure of the pressure-receiving chamber 84 drops significantly, and a force acts on the movable membrane 68 toward the pressure-receiving chamber 84, which is the upward side, 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 approximately 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. In particular, 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 almost the entire circumference, 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 connected to the equilibrium chamber 86 through the second outer peripheral through hole 60, and a relief passage 94 that connects the pressure receiving chamber 84 and the equilibrium chamber 86 to each other 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.

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 it is provided in the central part 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 ensures a larger flow rate.

Because 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 blocking the communication passage 82, thereby maintaining the communication state of the relief passage 94.

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 surface of the elastic protrusion 70 separates from the first wall inner surface 55 of the accommodation cavity 66, the tapered spherical crown shape of the protruding tip surface of the elastic protrusion 70 reduces the impact sound when it comes into contact with the first wall inner surface 55 again.

Figure 8 shows an engine mount 100 for an automobile as a second embodiment of a fluid-filled vibration-damping device constructed in accordance with the present invention. In the following description, the same components and parts as those in the first embodiment are denoted by the same reference numerals in the figure and will not be described.

The engine mount 100 has a structure in which a movable membrane 102 is disposed in a housing 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 peripheral end, and the upper surface of the outer peripheral end is a flat surface.

The first partition plate 106 constituting the partition member 104 has a plurality of grooves 108 that open to the wall inner surface (first wall inner surface 55) of the accommodation cavity 66 on the side of the pressure-receiving chamber 84. The grooves 108 extend radially in the outer peripheral portion of the accommodation cavity 66, and the inner peripheral end is open to the first outer peripheral through hole 52. In other words, the wall inner surface (first wall inner surface 55) on the side of the pressure-receiving chamber 84 of the accommodation cavity 66 has a plurality of ridges that extend radially and protrude downward, and the grooves 108 that open 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.

The first wall inner surface 55 of the storage cavity 66, at a portion circumferentially outside the groove 108, abuts against the upper surface of the outer peripheral end of the movable membrane 102. As a result, the outer peripheral end of the movable membrane 102 is vertically clamped by the partition member 104 at a portion circumferentially outside the groove 108. Therefore, the portion of the outer peripheral end of the movable membrane 102 that abuts against the first partition plate 106, circumferentially outside the groove 108, is the abutment portion in this embodiment.

By disposing the movable membrane 102 in the accommodation cavity 66, the lower opening of the groove 108 is covered by the movable membrane 102, and the groove 108 forms a radially extending communication passage 110. The inner peripheral end of the communication passage 110 is connected to the pressure-receiving chamber 84 through the first outer peripheral through hole 52, and the outer peripheral end is connected to the gap 80 provided on the outer peripheral side of the movable membrane 102.

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 are connected to 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 contact 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 contact 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 connected to the pressure-receiving chamber 84 through the communication passage 110, is connected to the equilibrium chamber 86 through the gap between the seal portion 72 and the seal abutment portion 64 and through the second outer peripheral through hole 60, and the relief passage that connects the pressure-receiving chamber 84 and the equilibrium chamber 86 is composed of the gap 80 and the communication passage 110. Then, the sealed fluid flows from the equilibrium chamber 86 to the pressure-receiving chamber 84 through the relief passage, suppressing the drop in the internal pressure of the pressure-receiving chamber 84 and preventing the occurrence of cavitation.

In the first embodiment, the movable membrane 68 is provided with an elastic protrusion 70, and the contact portion with the communication passage 82 is formed by providing unevenness in the overlapping portion of the outer periphery of the movable membrane 68 with the first wall inner surface 55. However, as in this embodiment, the contact portion with the communication passage 110 can also be formed by providing unevenness in the sandwiched portion of the movable membrane 102 in the partition member 104.

Figure 9 shows a partition member 120 in an engine mount as a third embodiment of a fluid-filled vibration-damping device constructed according to the present invention. Note that the structure of the fluid-filled vibration-damping device in this embodiment other than the partition member 120 is omitted from the illustration because the same structure as 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 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 part, for example, compared to the movable membrane 68 in the first embodiment. As a result, in this embodiment, the relief passage 124 is manifested in a manner different from that in the first embodiment.

Specifically, for example, in the first embodiment, the material, size, and compression ratio of the movable membrane 68 and elastic protrusion 70, etc., were adjusted to change the material, size, and compression ratio of the mounted state, so that the elastic protrusion 70 was easily compressed and deformed, causing the entire outer peripheral end of the movable membrane 68 to rise from the seal abutment portion 64 and create the relief passage 94. However, 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.

In this embodiment, when a relative pressure difference is applied to both sides of the movable membrane 122, the elastic deformation is likely to be expressed as an elastic deformation in the bending direction of the movable membrane 122 surface, and is unlikely to be expressed 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 decreases, an upward force acts on the movable membrane 122 due to the action of the relative internal pressure difference between the pressure-receiving chamber 84 and the equilibrium chamber 86, and as shown in FIG. 9, the part at 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, which is not easily affected by the deformation restraining force of the elastic protrusion 126) is elastically bent and deformed so as to rise upward. The movable membrane 122 in such a deformed state is shown in FIG. 10. Note that the buffer protrusion 78 is omitted from FIG. 10.

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, 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.

In this manner, in this embodiment, the gap that communicates 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 around the entire circumference. This allows the pressure-receiving chamber 84 and the equilibrium chamber 86 to communicate with each other through the relief passage 124, which includes the gap 80 and the communication passage 82, preventing the occurrence of cavitation.

The engine mount of this embodiment having the partition member 120 of the above-described structure can achieve the same effects as 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 between the elastic protrusions 126, 126 at the outer peripheral end of the movable membrane 122 (deformed portion 128) can be deformed to generate a raised portion 130 in the seal portion 72, thereby opening the relief passage 124.

Although the embodiments of the present invention have been described above in detail, 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 space between the grooves in the circumferential direction may be made into an elastic protrusion.

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

The specific sealing structure formed by pressing the seal portion against the seal abutment portion is not particularly limited as long as the structure provides a fluid-tight seal between the seal portion and the seal abutment portion. Specifically, for example, the abutment surface of the seal portion against the seal abutment portion may be a flat surface, and the seal protrusions that protrude continuously in the circumferential direction from the seal abutment portion may be pressed against the flat surface of the seal portion to seal between the seal portion and the seal abutment 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.

In addition, the part of the movable membrane that deforms and the specific deformation mode are not limited. 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 portion at the outer peripheral end of the movable membrane is separated from the seal abutment portion of the second partition plate, and the pressure-receiving chamber and the equilibrium chamber are connected by a relief passage. In the fluid-filled vibration-proof 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-proof characteristics, and the present invention can provide a fluid-filled vibration-proof device with a high degree of design freedom.

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 originally 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 having 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), wherein 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 according to (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 on the equilibrium chamber side of the accommodating space between the circumferential direction of the elastic protrusions, and the relief passage is generated at the portion 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 seal portion.
(iv) The fluid-filled vibration-damping device according to (ii) or (iii), wherein 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 spaced apart from the grooves in the circumferential direction, 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. 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 on 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 displacement of the outer peripheral end of the movable membrane toward the pressure-receiving chamber, and, for example, the sealing portion can be separated from the inner wall surface of the equilibrium chamber side of the accommodation space 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 cavity 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 separate from the inner wall surface on the equilibrium chamber side at the circumferential intervals of 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 of 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.
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, thereby improving the sealing performance by the sealing portion abutting against the inner wall surface on the equilibrium chamber side of the accommodating space, thereby improving the vibration-damping performance against the input of normal vibrations.

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 mounting portion 20 Fixing portion 22 Large diameter cylindrical portion 24 Small diameter cylindrical portion 26 Recess 28 Stopper rubber 30 Fitting rubber 32 Seal rubber layer 34 Flexible membrane 36 Fixing member 38 Fluid chamber 40 Partition member 42 First partition plate 44 Second partition plate 46 Circumferential groove 48 Central recess 50 First central through hole 52 First outer peripheral through hole 54 Accommodation recess 55 First wall inner surface 56 First narrowed portion 58 Second central through hole 60 Second outer peripheral through hole 62 Second narrowed portion 64 Seal abutment portion 65 Second wall inner surface 66 Accommodation space 68 Movable membrane 70 Elastic protrusion (abutment portion)
72 Seal portion 74 Outer circumferential lip (seal lip)
76 Inner lip (seal lip)
78 Buffer protrusion 80 Gap 82 Communication passage 84 Pressure receiving chamber 86 Equilibrium chamber 88 First communication port 90 Second communication port 92 Orifice passage 94 Relief passage 100 Engine mount (fluid filled type vibration damping device, second embodiment)
102 Movable membrane 104 Partition member 106 First partition plate 108 Groove 110 Communication passage 120 Partition member (third embodiment)
122 Movable membrane 124 Relief passage 126 Elastic protrusion 128 Deformed portion 130 Lifted portion

Claims (6)

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. 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. 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. 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.
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. 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 isolation 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. 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 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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