JP2008069905A - Vibration absorbing device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To suppress abnormal noises and vibration resulting from cavitation. <P>SOLUTION: A damping wall 96 is mounted on the outside of a communication port 62 of a partition member 48. The damping wall 96 is plate-shaped and its damping face 96A as part of the plate face includes a shock absorbing material. The damping wall 96 has one end side mounted on the lower side where an orifice 66 extends from the outside of the communication port 62 of the partition member 48. The damping wall 96 is arranged to be inclined to the side of the communication port 62, and its damping face 96A is arranged at a slant to the peripheral direction of the partition member 48 in opposition to a fluid outflowing direction X. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a vibration isolator that is applied to, for example, automobiles and general industrial machines and absorbs and attenuates vibrations transmitted from a vibration generating unit such as an engine to a vibration receiving unit such as a vehicle body.

  In an automobile, an engine mount as an anti-vibration device is disposed between the engine and the vehicle body (frame). The engine mount absorbs vibration energy by elastic deformation of the rubber elastic body, attenuates vibration from the engine, and suppresses transmission of vibration to the frame. In addition, as such an engine mount, there is a so-called liquid-sealed type equipped with a main liquid chamber, a secondary liquid chamber, and an orifice for connecting these liquid chambers inside, and in this liquid-filled engine mount, When the vibration is input, the liquid is circulated between the main liquid chamber and the sub liquid chamber through the orifice, and the resonance phenomenon (liquid column resonance) of the liquid is generated in the orifice, thereby damping the vibration of the elastic body itself. In addition, the vibration can be effectively attenuated and absorbed by the viscous resistance of the liquid.

  As an example of a liquid-filled vibration isolator applied as an engine mount as described above, there is a liquid-filled mount device disclosed in Patent Document 1, for example.

In the mounting device disclosed in Patent Document 1, a liquid chamber space sealed from the outside is formed by a mounting bracket, a rubber elastic body, and a diaphragm, and the liquid chamber space is formed by separating a resilient member by a partition member. It is divided into a main liquid chamber (pressure receiving chamber) as a part and a sub liquid chamber (equilibrium chamber) whose diaphragm is a part of the partition wall, and these main liquid chamber and sub liquid chamber are restricted by an orifice that is a restriction passage. It is connected. Here, the main liquid chamber, the sub liquid chamber, and the orifice are filled with a liquid such as water or ethylene glycol. The partition member is configured with an orifice that is a restricting passage for communicating the main liquid chamber and the sub liquid chamber on the outer peripheral side. In the mounting device, a plate-like movable plate is accommodated in the liquid chamber, and the movable plate can vibrate with a predetermined amplitude corresponding to high-frequency vibration along the amplitude direction of vibration.

  In the vibration isolator configured as described above, the elastic body is elastically deformed when a vibration is input, so that the vibration is attenuated and absorbed by the elastic body. At this time, when the frequency of the input vibration is lower than a predetermined value, the liquid flows between the main liquid chamber and the sub liquid chamber through the orifice. As a result, a resonance phenomenon (liquid column resonance) occurs in the liquid flowing through the orifice, so that the input vibration can be effectively damped by the action of the liquid column resonance.

  On the other hand, in the vibration isolator as described above, when the frequency of the input vibration is high frequency vibration higher than a predetermined value, the orifice is clogged, but the movable plate vibrates in synchronization with the input vibration. Thus, high-frequency vibration can be effectively absorbed.

  In the vibration isolator as described above, abnormal noise or vibration is generated when a relatively low frequency shake vibration is generated. This is because the liquid pressure in the main liquid chamber changes during shake vibration and the liquid flows between the main liquid chamber and the sub liquid chamber, thereby generating bubbles in the liquid and the bubbles disappearing. (So-called cavitation).

In the technique described in Patent Document 1, the buffer surface is formed at a position separated from the opening of the orifice toward the pressure receiving chamber (main liquid chamber) side by a predetermined distance. By applying air bubbles to the buffer surface, the air bubbles are decomposed to suppress the generation of large air bubbles.
JP 2004-190757 A

  However, since the buffer surface according to the first aspect is disposed in parallel to the circumferential direction with respect to the opening, the manner in which the bubbles in the liquid hit is insufficient.

  An object of the present invention is to provide a vibration isolator capable of suppressing abnormal noise and vibration caused by cavitation.

  In order to solve the above-described problem, a vibration isolator according to claim 1 of the present invention includes a first attachment member connected to one of the vibration generating unit and the vibration receiving unit, and the other of the vibration generating unit and the vibration receiving unit. A second mounting member to be connected, an elastic body disposed between the first mounting member and the second mounting member, and the elastic body is configured as a part of a partition wall to enclose a liquid. A main liquid chamber whose internal volume changes with deformation of the elastic body, a sub liquid chamber in which liquid is enclosed, and at least a part of the partition wall is formed by a diaphragm and can be expanded and contracted; the main liquid chamber; A restricting passage constituting member disposed between the sub liquid chamber and configured to restrict the main liquid chamber and the sub liquid chamber to communicate with each other on the outer peripheral side surface, and to the main liquid chamber of the restricting passage. Outside the opening of the restriction passage structure so as to face the liquid outflow direction of the liquid. Providing the buffer wall having a buffering surface inclined with respect to the circumferential direction of the member, characterized by.

  In the vibration isolator according to the first aspect, when the elastic body is elastically deformed when vibration is input, the vibration is attenuated and absorbed by the elastic body that is the main body of vibration absorption, and the amplitude of the input vibration is larger than a predetermined value. Since the liquid flows between the main liquid chamber and the sub liquid chamber through the restriction passage, a resonance phenomenon (liquid column resonance) occurs in the liquid flowing through the restriction passage. Input vibration is damped.

  As described above, in the vibration isolator in which the liquid flows between the main liquid chamber and the sub liquid chamber, the generation and disappearance of bubbles (so-called cavitation) in the restricted flow path and the liquid in the main liquid chamber when the liquid flows. Is observed. The disappearance of the generated bubbles is considered to be a cause of the abnormal noise and vibration described above.

  In particular, bubbles tend to be generated in the restricted passage because the liquid flows at a high speed. In addition, the main liquid chamber in which the partition wall is made of an elastic material has a larger change in the hydraulic pressure than the sub liquid chamber in which the partition wall is made of a diaphragm, and bubbles are likely to be generated and flow into the main liquid chamber from the restriction passage. Air bubbles tend to grow.

  Therefore, in the invention according to claim 1, a buffer wall is provided outside the opening portion of the restriction passage to the main liquid chamber. The buffer surface of the buffer wall is disposed so as to be inclined with respect to the circumferential direction of the restriction passage constituting member so as to face the liquid outflow direction of the liquid. By arranging the buffer surface of the buffer wall so as to be inclined in this manner, the liquid pressure of the liquid flowing out from the restriction passage temporarily rises in the vicinity of the buffer surface. Accordingly, at least a part of the bubbles generated in the restriction passage and flowing out to the main liquid chamber can be eliminated or decomposed to suppress the bubble growth in the main liquid chamber. Further, since the bubbles can be extinguished near the buffer surface, the noise and vibration at the time of bubble disappearance can be suppressed by configuring the buffer surface with an impact absorbing material.

  The vibration isolator according to claim 2 of the present invention is the vibration isolator according to claim 1, wherein the buffer surface is arranged in a direction substantially orthogonal to the liquid outflow direction.

  Here, the term “substantially orthogonal” includes not only the relationship in which the liquid outflow direction is the normal direction with respect to the buffer surface, but also includes an inclination range of about 10 ° from the normal direction.

  Thus, by arranging the buffer surface, the liquid flowing out from the restriction passage can be applied to the buffer surface vigorously, and the bubbles can be efficiently decomposed and extinguished.

  The vibration isolator according to claim 3 of the present invention is the vibration isolator according to claim 1 or 2, characterized in that the buffer wall is attached to the restricting passage constituting member.

  As described above, by attaching the buffer wall to the restricting passage constituting member, the buffer surface can be easily tilted in the circumferential direction.

  As described above, according to the vibration isolator of the present invention, it is possible to suppress abnormal noise and vibration caused by cavitation.

  Hereinafter, a vibration isolator according to an embodiment of the present invention will be described with reference to the drawings.

  FIG. 1 shows a vibration isolator according to an embodiment of the present invention. The vibration isolator 10 is applied as an engine mount that supports an engine that is a vibration generating unit in an automobile to a vehicle body that is a vibration receiving unit. 1 indicates the axis of the apparatus, and the following description will be given with the direction along the axis S as the axial direction of the apparatus.

  As shown in FIG. 1, the vibration isolator 10 is disposed substantially coaxially on the inner cylinder fitting 12 formed in a substantially thick cylindrical shape connected to the engine side and on the outer peripheral side of the inner cylinder fitting 12. A substantially cylindrical outer cylinder fitting 14 connected to the vehicle body side, and a rubber elastic body 16 which is disposed between the inner cylinder fitting 12 and the outer cylinder fitting 14 and serves as a main vibration absorber. The inner cylinder fitting 12 has an upper end inserted into the outer cylinder fitting 14 and a lower end protruding through the opening on the lower end side of the outer cylinder fitting 14 to the lower side of the outer cylinder fitting 14. A stepped portion 18 is formed in the axially intermediate portion of the outer cylinder fitting 14, and a diameter-enlarged portion 20 having a diameter larger than that of the lower side is formed above the stepped portion 18. In addition, the outer cylindrical metal fitting 14 is formed with a tapered portion 22 whose diameter is tapered downward at the lower end portion thereof, and is caulked at the upper end portion of the enlarged diameter portion 20 toward the inner peripheral side when the apparatus is assembled. A caulking portion 24 to be formed is formed.

  The vibration isolator 10 includes a substantially cup-shaped connecting tube 26 in which the lower end side of the outer tube fitting 14 is fitted and fixed, and a substantially bottomed cylindrical holder fitting 28 in which the lower end side of the connecting tube 26 is fitted and fixed. Is provided. The outer cylinder fitting 14 is inserted into the connecting cylinder 26 until the lower end thereof is in contact with the bottom plate portion of the connecting cylinder 26. A plurality of leg portions 30 and 32 are fixed to the outer peripheral surface of the holder metal fitting 28 by welding or the like, and bolts (not shown) are inserted through the connecting holes 33 formed on the distal ends of the leg portions 30 and 32. ), The holder fitting 28 is fastened and fixed to the vehicle body side. As a result, the outer cylinder fitting 14 is connected and fixed to the vehicle body via the connection cylinder 26 and the holder fitting 28.

  The lower end side of the inner cylinder fitting 12 protrudes to the lower side of the connection cylinder 26 through an opening 26A formed in the bottom plate portion of the connection cylinder 26, and the lower end portion of the inner cylinder fitting 12 is connected to the engine by a bolt 34. The base end portion of the bracket 36 is fastened and fixed. The bracket 36 extends to the outer peripheral side through an opening (not shown) formed in the side surface portion of the holder metal 28, and an engine (not shown) is fastened and fixed to the front end side of the bracket 36 by a bolt or the like. Is done. Further, a stopper rubber 38 formed in a substantially rectangular tube shape is covered on the base end portion of the bracket 36, and the upper surface portion of the stopper rubber 38 is in pressure contact with the bottom plate portion of the connecting cylinder 26. Thereby, an excessive displacement along the axial direction of the bracket 36 is prevented, and generation of a loud collision sound is prevented even when the bracket 36 collides with the connecting cylinder 26 or the holder fitting 28 due to an input of a large load. .

  A bottom plate portion of an extension fitting 40 formed in a substantially cup shape that opens upward is fixed to the upper end surface of the inner cylinder fitting 12 by welding or the like. The extension fitting 40 has a tapered shape whose side plate portion is enlarged in diameter from the bottom plate side toward the upper end side, and a ring-shaped flange member 42 is fixed to the upper end portion of the side plate portion by welding or the like. It extends from the upper end of the extension fitting 40 to the inner peripheral side. In addition, a plurality of runner holes 44 for filling the extension metal fitting 40 with vulcanized rubber which is a molding material of the elastic body 16 are formed in the side plate portion of the extension metal fitting 40.

  The elastic body 16 is vulcanized and bonded to the upper end side of the inner cylinder fitting 12 inserted into the outer cylinder fitting 14 and the extension fitting 40, and is vulcanized and bonded to the lower end side of the outer cylinder fitting 14, The tube fitting 12 and the outer tube fitting 14 are connected elastically. Here, the elastic body 16 is vulcanized and bonded to the outer peripheral surface of the inner cylindrical metal member 12 and the outer peripheral surface of the extension metal member 40, and filled into the inner peripheral side of the extension metal member 40 through the runner hole 44. The inner peripheral surface and bottom surface of the metal fitting 40 and the lower surface of the flange member 42 are also vulcanized and bonded. Further, the elastic body 16 is integrally formed with a thin covering portion 46 extending upward from the outer peripheral portion, and this covering portion 46 is vulcanized on the upper end side on the inner peripheral surface of the outer cylinder fitting 14. It is bonded and covers the inner peripheral surface of the outer cylinder fitting 14.

  A partition member 48 formed in a substantially disc shape as a whole and a substantially hat-shaped partition bracket 50 in close contact with the upper surface portion of the partition member 48 are inserted into the outer cylindrical member 14 above the step portion 18. ing. The outer peripheral portion of the lower surface of the partition member 48 is in contact with the stepped portion 18 via the covering portion 46. A cylindrical support cylinder 52 is fitted into the outer cylinder fitting 14 above the partition member 48 and the partition fitting 50, and the lower end portion of the support cylinder 52 abuts on the outer peripheral portion of the partition fitting 50. Yes. In the outer cylinder fitting 14 into which the partition member 48, the partition fitting 50 and the support cylinder 52 are inserted, the caulking portion is caulked toward the inner peripheral side. Thereby, the partition member 48, the partition fitting 50, and the support cylinder 52 are fixed between the stepped portion 18 and the caulking portion 24 in the outer cylinder fitting 14. An outer peripheral portion of a rubber diaphragm 54 formed in a convex cup shape is formed on the inner peripheral surface of the support cylinder 52 by vulcanization over the entire circumference.

  In the vibration isolator 10, a liquid chamber space that is sealed from the outside is formed by the outer cylindrical metal member 14, the elastic body 16, and the diaphragm 54. The liquid chamber space is divided into a main liquid chamber 56 having the elastic body 16 as a part of the partition wall and a sub liquid chamber 58 having the diaphragm 54 as a part of the partition wall by the partition member 48 and the partition fitting 50. In the vibration isolator 10, the outside of the diaphragm 54 that forms a part of the partition wall of the sub liquid chamber 58 is an atmospheric space, so that the diaphragm 54 responds to changes in the liquid pressure in the sub liquid chamber 58. The liquid chamber 58 is elastically deformable so as to expand and contract the internal volume. The main volume of the main liquid chamber 56 expands and contracts with the elastic deformation of the elastic body 16.

  The partition member 48 is provided with a concave groove 60 extending in the circumferential direction on the outer peripheral surface thereof. As shown in FIG. 2B, the groove portion 60 extends in a C shape along the circumferential direction with the axis S as the center, and the partition member 48 extends downward from one end portion of the groove portion 60. The lower side of the groove portion 60 is cut away to form the communication port 62, and the upper side of the groove portion 60 is cut upward from the other end portion of the groove portion 60 to form the communication port 64. As shown in FIG. 1, the groove portion 60 is closed on the outer peripheral side thereof by the inner peripheral surface of the outer cylinder fitting 14 via the covering portion 46, thereby restricting the communication between the main liquid chamber 56 and the sub liquid chamber 58. An orifice 66 is formed as a passage.

  The main liquid chamber 56, the sub liquid chamber 58, and the orifice 66 are filled with a liquid such as water, ethylene glycol, or silicone oil, and this liquid passes between the main liquid chamber 56 and the sub liquid chamber 58 through the orifice 66. It is possible to distribute with. The orifice 66 is set (tuned) so that its path length and cross-sectional area match the amplitude and frequency of the shake vibration.

  The partition member 48 has a circular convex thick portion 68 formed at the center of the upper surface thereof, and a circular concave portion 70 is formed at the central portion of the thick portion 68. In addition, the partition member 48 is formed with a circular concave relief portion 72 having a diameter larger than that of the thick portion 68 at the center of the lower surface, and between the top surface of the relief portion 72 and the bottom surface of the concave portion 70. Is provided with a bottom plate portion 90 having a substantially constant thickness. In the escape portion 72, the extension fitting 40 and the upper end portion of the elastic body 16 are inserted while leaving a gap with the bottom plate portion 90 along the axial direction. Here, the gap between the bottom plate portion 90 and the extension fitting 40 and the elastic body 16 is less than the illustrated state when the engine is connected to the bracket 36 and a load resulting from the weight of the engine is input to the bracket 36. Therefore, even if vibration is input, the extension fitting 40 and the elastic body 16 do not contact the bottom plate portion 90.

  The partition fitting 50 is formed with a circular convex outer fitting portion 74 corresponding to the thick portion 68 of the partition member 48 at the center thereof, and extends from the lower end portion of the outer fitting portion 74 to the outer peripheral side. An annular flange portion 76 is integrally formed. The partition fitting 50 externally fits the outer fitting portion 74 to the thick portion 68 of the partition member 48 from above, and makes the flange portion 76 contact the outer peripheral portion of the partition member 48. As a result, the upper surface side of the concave portion 70 of the partition member 48 is closed by the top plate portion 78 of the outer fitting portion 74, and a storage chamber 80 partitioned from the main liquid chamber 56 and the sub liquid chamber 58 is provided in the concave portion 70. In the storage chamber 80, a disk-shaped space having a substantially constant thickness along the axial direction is formed. Further, as shown in FIG. 2 (B), the partition fitting 50 is formed with a notch portion 82 that is cut out in a substantially rectangular shape from the outer peripheral end toward the inner periphery side. The communication port 64 of the orifice 66 communicates with the auxiliary liquid chamber 58.

  As shown in FIG. 2 (B), the partition metal 50 has a plurality of fan-shaped openings 88 in the top plate portion 78 whose dimensions extend in the circumferential direction from the inner periphery toward the outer periphery (this embodiment). In the form, 4 pieces are drilled. The storage chamber 80 communicates with the auxiliary liquid chamber 58 through the opening 88. As shown in FIG. 2A, the bottom plate portion 90 of the partition member 48 also has a plurality of openings 92 having the same shape and opening area as the openings 88 of the partition metal fitting 50 (in this embodiment, 4) are drilled. The storage chamber 80 communicates with the main liquid chamber 56 through the opening 92. In the storage chamber 80, a movable plate 94 formed in a substantially disc shape using rubber as a material is stored.

  The movable plate 94 is formed in a disc shape whose thickness is substantially constant at any part along the radial direction. Here, the thickness PT (see FIG. 2A) of the movable plate 94 is shorter than the thickness ST along the axial direction of the storage chamber 80 by a predetermined dimension. Specifically, for example, the difference between the thickness of the movable plate 94 and the thickness ST of the PT storage chamber 80 is shorter than the amplitude of the shake vibration, which is a relatively low frequency vibration, and is a relatively high frequency vibration. It is set to be longer than the amplitude of idle vibration. As a result, the amplitude difference between the low frequency vibration and the high frequency vibration along the axial direction between the movable plate 94 stored in the storage chamber 80 and the top plate portion 78 of the partition member 50 and the bottom plate portion 90 of the partition member 48. A gap having a width dT corresponding to is formed.

  As shown in FIG. 2A, the outer peripheral end of the movable plate 94 extends to the outer peripheral side from the outer peripheral end of the opening 92 of the bottom plate portion 90 and the opening 88 of the partition fitting 50. The outer diameter of the movable plate 94 is slightly smaller than the inner diameter of the storage chamber 80. Thereby, the movable plate 94 can be reciprocated (vibrated) within the range of the width dT along the axial direction while being accommodated in the storage chamber 80.

  As shown in FIG. 3, a buffer wall 96 is attached to the outside of the communication port 62 of the partition member 48. The buffer wall 96 is plate-shaped, and the buffer surface 96A constituting the plate surface is configured to include a material capable of absorbing shock. As a material capable of absorbing shock, rubbers such as butyl rubber (IIR) and styrene butadiene rubber (SBR), resins such as polystyrene and polyisobutylene can be used.

  One end of the buffer wall 96 is attached to the lower side of the partition member 48 where the orifice 66 is extended outside the communication port 62. The buffer wall 96 is disposed so as to be inclined toward the communication port 62, and the circumferential direction of the partition member 48 is opposed to the liquid outflow direction from the orifice 66 (hereinafter, this direction is referred to as “liquid outflow direction X”). The buffer surface 96A is disposed so as to be inclined with respect to the surface.

  Here, the inclination angle of the buffer surface 96A is preferably an angle at which the liquid flowing out in the liquid outflow direction X is substantially orthogonal to the buffer surface 96A. By arranging in this way, the liquid can be applied to the buffer surface 96A with vigor.

  Further, it is preferable that the buffer surface 96A has a rough surface for bubble decomposition.

  Next, the operation of the vibration isolator 10 according to the first embodiment of the present invention configured as described above will be described.

  In the vibration isolator 10, when the elastic body 16, which is the main vibration absorber, is elastically deformed by vibration when vibration is input from the engine or the vehicle body side, the vibration is attenuated and absorbed by the elastic body 16.

  In the vibration isolator 10, when the vibration is input from the engine or the vehicle body side, the elastic body 16 is elastically deformed and the hydraulic pressure in the main liquid chamber 56 is changed in synchronization with the vibration input. Along with this change in liquid pressure, liquid flows between the main liquid chamber 56 and the sub liquid chamber 58 through the orifice 66.

  Bubbles are generated in the orifice 66 and the main liquid chamber 56 due to the change in the liquid pressure in the main liquid chamber 56 and the flow of the liquid. In particular, a large number of bubbles are generated in the orifice 66 because the liquid flow rate is high. When the bubbles generated in the orifice 66 flow into the main liquid chamber 56, they are decomposed by hitting the buffer surface 96A of the buffer wall 96, or disappear due to an increase in the fluid pressure in the vicinity of the communication port 62 side of the buffer surface 96A. .

  In the present embodiment, since the buffer surface 96A is inclined so as to face the liquid outflow direction X with respect to the circumferential direction of the partition member 48, the bubbles generated in the orifice 66 can be applied to the buffer surface 96A vigorously. The bubbles can be efficiently decomposed and eliminated. Thereby, the bubble growth in the main liquid chamber 56 can be suppressed.

  Further, since the bubbles can be extinguished in the vicinity of the buffer surface 96A, the noise and vibration at the time of the decomposition and extinction of the bubbles can be suppressed by the buffer surface 96A made of the shock absorbing material.

  On the other hand, a hydraulic pressure (pressure wave) that periodically changes in synchronization with the input vibration acts on the movable plate 94 that communicates with the main fluid chamber 56 and is accommodated in the accommodation chamber 80. As a result, the movable plate 94 vibrates up and down along the axial direction as the hydraulic pressure in the main liquid chamber 56 changes. At this time, the movable plate 94 vibrates up and down in synchronization with the fluid pressure change in the main fluid chamber 56 in the storage chamber 80 and contacts the top plate portion 78 of the partition fitting 50 and the bottom plate portion 90 of the partition member 48, respectively. Repeat the contact and separation.

  In the vibration isolator 10, as described above, the front and back surfaces of the movable plate 94 abut on the top plate portion 78 of the partition fitting 50 and the bottom plate portion 90 of the partition member 48 in synchronization with the change in hydraulic pressure in the main liquid chamber 56. When the separating operation is repeated, the movable plate 94 moves between the movable plate 94 and the opening 88 of the top plate 78 and the opening 92 of the bottom plate 90 within the range of the width dT (see FIG. 2A). Since a gap having a width corresponding to a position along the axial direction of 94 is formed, the liquid flows between the main liquid chamber 56 and the sub liquid chamber 58 through the gap and the openings 88 and 92. May occur. On the other hand, in the vibration isolator 10, when the movable plate 94 that vibrates in synchronization with the fluid pressure change in the main liquid chamber 56 comes into close contact with one of the top plate portion 78 of the partition metal fitting 50 and the bottom plate portion 90 of the partition member 48, the movable plate 94, one of the opening 92 and the opening 88 is closed and the storage chamber 80 is closed, so that the liquid flows between the main liquid chamber 56 and the sub liquid chamber 58 through the storage chamber 80. Is substantially prevented.

  Specifically, in the vibration isolator 10, when the frequency of the input vibration is equal to or less than the frequency of the shake vibration (for example, 8 to 12 Hz) and the amplitude is large (for example, about 0.5 mm to 1 mm), The movable plate 94 comes into close contact with the bottom plate portion 90 of the partition member 48 or the top plate portion 78 of the partition fitting 50, and one of the openings 88 and 92 is closed. Accordingly, the liquid does not substantially flow between the main liquid chamber 56 and the sub liquid chamber 58 through the storage chamber 80, and only between the main liquid chamber 56 and the sub liquid chamber 58 through the orifice 66. The liquid circulates in each other. Here, the orifice 66 is tuned so that its path length and cross-sectional area are adapted to shake vibration. As a result, in the vibration isolator 10, when the input vibration is particularly shake vibration, a resonance phenomenon (liquid column resonance) occurs in the liquid flowing through the orifice 66, and the input vibration is effectively reduced by the action of the liquid column resonance. Can be attenuated.

  In the vibration isolator 10, when the frequency of the input vibration is higher than the frequency of the shake vibration and the amplitude is small, for example, the input vibration is idle vibration (for example, 20 to 30 Hz) and the amplitude is 0.1 mm to 0. In the case of about 2 mm, the orifice 66 tuned to match the shake vibration becomes clogged, and it is difficult for the liquid to flow through the orifice 66, but the movable plate 94 is synchronized with the input vibration in the storage chamber 80. Then, since the gap is formed between the movable plate 94 and the top plate portion 78 and the bottom plate portion 90 by vibrating up and down, the main liquid chamber 56 passes through the openings 88 and 92 and the storage chamber 80. Since liquid flows between the auxiliary liquid chamber 58 and the liquid spring in the main liquid chamber 56, an increase in the dynamic spring constant associated with an increase in the hydraulic pressure can be suppressed. Movement It constants were kept low, the high-frequency vibration can be effectively absorbed by the elastic deformation of the elastic body 16.

  Note that the vibration isolator of the present invention is not limited to the above-described vibration isolator, and can be applied to any liquid-sealed vibration isolator.

It is sectional drawing which shows the structure of the vibration isolator which concerns on embodiment of this invention. The structure of the partition member and partition metal fitting which accommodated the movable plate shown by FIG. 1 is shown, (A) is side surface sectional drawing, (B) is a perspective view. It is a figure which shows the main liquid chamber side exit vicinity of the orifice of the vibration isolator which concerns on embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Anti-vibration apparatus 12 Inner cylinder metal fitting 14 Outer cylinder metal fitting 16 Elastic body 48 Partition member 54 Diaphragm 56 Main liquid chamber 58 Sub liquid chamber 62 Communication port 66 Orifice 96 Buffer wall 96A Buffer surface X Liquid outflow direction

Claims (3)

A first attachment member coupled to one of the vibration generator and the vibration receiver;
A second attachment member coupled to the other of the vibration generating portion and the vibration receiving portion;
An elastic body disposed between the first mounting member and the second mounting member;
A main liquid chamber in which the elastic body is configured as a part of a partition wall and liquid is enclosed, and the internal volume changes with deformation of the elastic body;
A sub-liquid chamber in which liquid is enclosed, and at least a part of the partition wall is formed by a diaphragm and can be expanded and contracted;
A restricting passage constituting member which is disposed between the main liquid chamber and the sub liquid chamber and is configured to restrict the main liquid chamber and the sub liquid chamber to communicate with each other on an outer peripheral side surface;
With
A buffer wall having a buffer surface inclined with respect to the circumferential direction of the restricting passage constituting member is provided outside the opening portion of the restricting passage to the main liquid chamber so as to face the liquid outflow direction of the liquid. The vibration isolator characterized by the above.   The vibration isolator according to claim 1, wherein the buffer surface is arranged in a direction substantially orthogonal to the liquid outflow direction.   The vibration isolator according to claim 1 or 2, wherein the buffer wall is attached to the restriction passage constituting member.

Images