JP2006038015A - Vibration damper - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To effectively absorb a vibration with a specified frequency by vibrating a movable plate disposed in a partition member partitioning a main liquid chamber from an auxiliary liquid chamber when the vibration with the specified frequency is inputted and prevent an abnormal noise produced by the contact of the movable plate with the partition member from occurring. <P>SOLUTION: In this vibration damper 10, the movable plate 94 is formed of a rubber compound including oleic acid as a lubrication component. By this, the oleic acid is gradually oozed onto the surface of the rubber of the movable plate 94 over a long period of time, and the oleic acid acts thereon as a self-lubricant. Accordingly, even if the vibration is inputted from an engine or a vehicle body side, and the movable plate 94 is moved into a storage chamber 80 while slidably coming into contact, on its outer peripheral surface, with the inner peripheral surface of the inside of the storage chamber 80 and the movable plate 94 is repeatedly press-contacted to a top plate part 78 or a bottom plate part 90 in the storage chamber 80, the frictional resistance of the movable plate 94 is sufficiently reduced by the lubricating action of the oleic acid. Thus, a slipping noise caused by the slidable contact of the movable plate 94 with the inner peripheral surface of the storage chamber 80 and a creak produced when the movable plate 94 is press-contacted to the top plate part 78 and the bottom plate part 90 are prevented from occurring. <P>COPYRIGHT: (C)2006,JPO&NCIPI

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 the liquid-filled vibration isolator applied as the 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 an outer cylinder, a rubber elastic body, and a diaphragm. The main liquid chamber is divided into a sub liquid chamber having a diaphragm as a part of the partition wall, and the main liquid chamber and the sub liquid chamber are connected by an orifice serving as a restriction passage. 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 provided with an orifice which is a restricting passage for communicating the main liquid chamber and the sub liquid chamber on the outer peripheral side. The partition member is provided with a storage chamber which is a cylindrical space on the inner peripheral side thereof, and the storage chamber communicates with the main liquid chamber and the sub liquid chamber through an opening formed in the partition member. In the mount device, a disc-shaped movable plate is accommodated in the accommodation chamber, and this movable plate can be vibrated 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 movable plate is in close contact with the peripheral edge of the opening in the partition member, so that the liquid passes through the storage chamber and the main liquid chamber and the auxiliary liquid. The liquid does not substantially flow between the chambers, and the liquid flows between the main liquid chamber and the sub liquid chamber only 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 is synchronized with the input vibration in the storage chamber. Since the liquid flows between the main liquid chamber and the sub liquid chamber through the storage chamber, the increase in the dynamic spring constant accompanying the increase in the liquid pressure in the main liquid chamber can be suppressed. Even when such high-frequency vibration is input, the dynamic spring constant of the elastic body is kept low, and high-frequency vibration can be effectively absorbed by elastic deformation of the elastic body.
JP-A-1-193425

  However, in the vibration isolator as described above, the movable plate vibrates along the amplitude direction of the input vibration when high-frequency vibration is input. At this time, the movable plate moves in the storage chamber with its outer peripheral surface slidingly contacted with the inner peripheral surface of the storage chamber, and a pair of inner wall surfaces facing each other along the amplitude direction in the storage chamber (partition member). Press contact repeatedly with a period corresponding to the frequency of the input vibration. As a result, in a vehicle to which such a vibration isolator is applied, the noise generated when the movable plate slides against the inner peripheral surface of the storage chamber during movement in the vibration isolator, or when the movable plate presses against the partition member. The squeaking noise generated in the vehicle is generated at the time of vibration input, and this rubbing sound and squeaking noise may be transmitted as abnormal noise to the vehicle through the vehicle body.

  In view of the above facts, the object of the present invention is to determine whether the movable plate provided in the partition member that divides the main liquid chamber and the sub liquid chamber vibrates when a vibration having a predetermined frequency is input. It is possible to provide an anti-vibration device that can effectively absorb vibration having the above frequency and can prevent generation of abnormal noise caused by the movable plate coming into contact with the partition member.

  In order to solve the above-described problem, a vibration isolator according to claim 1 of the present invention includes a first mounting 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 arranged between the first mounting member and the second mounting member, and a liquid are sealed, and the elastic body is used as a part of the partition wall to A main liquid chamber whose internal volume changes as the body deforms, a sub liquid chamber in which liquid is enclosed, and at least a part of a partition wall is formed by a diaphragm and can be expanded and contracted, and the main liquid chamber and the sub liquid chamber A partition member in which a hollow storage chamber is provided, and an opening for communicating the storage chamber with the main liquid chamber and the sub liquid chamber is formed, and the main liquid chamber And a restriction passage that communicates with the auxiliary liquid chamber, and restricts the liquid from flowing into the storage chamber. A gap having a predetermined dimension is formed between the opening of the partition member and the opening peripheral edge where the opening is opened, and the gap is provided when vibration is input to the first or second mounting member. And a movable plate that is in contact with and separated from the peripheral edge of the opening in synchronization with the vibration, wherein the movable plate has a self-lubricating rubber composition having self-lubricating properties. It is formed by a thing.

  In the vibration isolator according to the first aspect, when the elastic body is elastically deformed at the time of vibration input, the vibration is attenuated and absorbed by the elastic body and the amplitude of the input vibration is larger than a predetermined value. The movable plate is in close contact with the peripheral edge of the opening in the partition member, so that liquid does not substantially flow between the main liquid chamber and the sub liquid chamber through the storage chamber, and only through the restriction passage. Since the liquid flows between the liquid chamber and the auxiliary liquid chamber, a resonance phenomenon (liquid column resonance) occurs in the liquid flowing in the restriction passage, and the input vibration is effectively attenuated by the action of the liquid column resonance. it can.

  In the vibration isolator according to the first aspect, when the amplitude of the input vibration is smaller than the predetermined value, the restriction passage is clogged and it is difficult for the liquid to flow through the restriction passage. By vibrating in synchronization with the input vibration, the liquid flows between the main liquid chamber and the sub liquid chamber through the storage chamber, so that the increase in the dynamic spring constant accompanying the increase in the liquid pressure in the main liquid chamber is suppressed. The dynamic spring constant of the elastic body can be kept low even when such high frequency vibration is input, and the high frequency vibration can be effectively absorbed by elastic deformation of the elastic body.

  In the vibration isolator according to claim 1, since the movable plate is formed of a self-lubricating rubber composition having self-lubricating property, vibration is input to the first mounting member or the second mounting member, and the movable plate When the movable plate vibrates along the amplitude direction of the input vibration, the movable plate moves in the storage chamber while sliding the outer peripheral surface of the movable plate on the inner peripheral surface of the storage chamber, and the movable plate moves the amplitude of the partition member in the storage chamber. Even when repeatedly pressed against a pair of opening peripheral portions facing each other along the direction, the friction resistance between the movable plate and the inner peripheral surface of the storage chamber and the opening peripheral portion becomes sufficiently small due to the self-lubricating property of the movable plate. Therefore, it is possible to effectively prevent the generation of the squeaking noise generated when the movable plate is in sliding contact with the inner peripheral surface of the storage chamber and the squeaking noise generated when the movable plate is pressed against the peripheral edge of the opening.

  A vibration isolator according to claim 2 of the present invention is characterized in that in the vibration isolator according to claim 1, the movable plate is formed of a rubber composition to which oleic acid is added as a lubricating component.

  The vibration isolator according to claim 3 of the present invention is the vibration isolator according to claim 2, characterized in that the content of oleic acid in the rubber composition is 0.2 wt% to 3 wt%.

Further, the vibration isolator according to claim 4 of the present invention is the vibration isolator according to claim 1, 2 or 3, wherein the movable plate has a curved surface whose front and back surfaces along the thickness direction are respectively convex. Are formed in a substantially convex lens shape, and are stored in the storage chamber so that the center portions of the front and back surfaces of the movable plate are in pressure contact with the inner wall surface of the partition member, respectively.
At the time of vibration input to the first or second mounting member, a bending region on the outer peripheral side with respect to the central portion that is in pressure contact with the inner wall surface of the storage chamber in front of the movable plate in synchronization with the vibration input is the peripheral edge of the opening It is characterized by coming into contact with and separating from the part.

  As described above, according to the vibration isolator of the present invention, when a vibration having a predetermined frequency is input, the movable plate arranged in the partition member that partitions the main liquid chamber and the sub liquid chamber vibrates. Can effectively absorb vibration having a predetermined frequency, and can prevent generation of abnormal noise caused by the movable plate coming into contact with the partition member.

  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. In the outer cylinder 14, an enlarged diameter portion 20 having a diameter larger than the diameter of the lower end portion is formed in the upper end portion with respect to the step portion 18 provided in the intermediate portion in the axial direction. 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. In addition, 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 32 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 92 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 and bonded to the upper end side of the inner peripheral surface of the outer cylinder fitting 14. Thus, the inner peripheral surface of the outer cylinder fitting 14 is covered.

  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. The outer peripheral portion of the lower surface of the partition member 48 is in contact with the step portion 18 through 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. Here, an outer peripheral portion of a rubber diaphragm 54 formed in a convex cup shape on the inner peripheral surface of the support cylinder 52 is vulcanized and bonded over the entire periphery.

  In the vibration isolator 10, a liquid chamber space sealed from the outside is formed by the outer cylinder fitting 14, the elastic body 16, and the diaphragm 54, and this liquid chamber space is elastic by the partition member 48 and the partition fitting 50. 16 is divided into a main liquid chamber 56 having a part of the partition wall 16 and a sub liquid chamber 58 having the diaphragm 54 a part of the partition wall. 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. 2, the groove portion 60 extends in a C shape along the circumferential direction centering on the axis S, and the partition member 48 has a groove portion extending downward from one end portion of the groove portion 60. The communication port 62 is formed by cutting out the lower side of the groove 60, and the communication port 64 is formed by cutting out the upper side of the groove 60 from the other end of the groove 60 upward. Here, as shown in FIG. 1, the outer peripheral side of the groove portion 60 is closed by the inner peripheral surface of the outer cylindrical metal member 14 via the covering portion 46, so that the main liquid chamber 56 and the sub liquid chamber 58 are separated. An orifice 66 is formed as a restricting passage for communication.

  Here, the main liquid chamber 56, the sub liquid chamber 58, and the orifice 66 are filled with incompressible liquid such as water, ethylene glycol, and silicone oil, and this liquid passes through the orifice 66 and the main liquid chamber 56. It is possible to circulate between the secondary liquid chamber 58. 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.

  In the vibration isolator 10, the movable plate 94 is formed of a self-lubricating rubber composition having self-lubricating properties. Various known lubricant components can be used in the rubber composition. In this embodiment, oleic acid can be used as a particularly preferable lubricant component. The oleic acid content is preferably 0.2 wt% to 3 wt%. That is, if the content is less than 0.2 wt%, the effect of reducing friction is insufficient, and the effect of preventing the generation of abnormal noise is insufficient. If the content exceeds 3 wt%, the rubber component oozes out the lubricating component. The speed (bloom speed) becomes sufficiently large, and a large friction reducing effect can be obtained, but the mechanical properties of rubber may be lowered, and the workability may also be lowered.

  Moreover, in this embodiment, various rubbers conventionally used for applications such as vibration isolation are used as the rubber component. Specifically, natural rubber (NR), styrene-butadiene rubber (SBR), butadiene rubber (BR) or a mixed rubber thereof is used. If necessary, sulfur, morpholine disulfide, tetra A vulcanizing agent such as methyl thiuram disulfide is added.

  In addition to oleic acid, the lubricating component added to the rubber component is a known lubricating component, for example, a polyethylene glycol type surfactant such as polyoxyethylene alkyl ether, polyoxyethylene alkyl phenyl ether, hydroxy -Fatty acid amides such as stearamide, erucylamide, ethylene bis-stearamide, ethylene bis-lauryl amide may be used.

  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 the change in the liquid pressure, the liquid flows between the main liquid chamber 56 and the sub liquid chamber 58 through the orifice 66, and the movable plate 94 stored in the storage chamber 80 communicating with the main liquid chamber 56. The fluid pressure (pressure wave) that periodically changes in synchronization with the input vibration acts. 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 liquid chamber 56 in the storage chamber 80, and at the same time 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. At this time, the movable plate 94 vibrates between the top plate portion 78 and the bottom plate portion 90 while the outer peripheral surface thereof is in sliding contact with the inner peripheral surface of the storage chamber 80.

  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, the vibration isolator 10 is movable 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, 0.5 mm to 1 mm). The 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, when the input vibration is idle vibration (for example, 20 to 30 Hz) and the amplitude is small (for example, , 0.1 mm to 0.2 mm), the orifice 66 tuned to match the shake vibration is clogged, and it is difficult for liquid to flow through the orifice 66. By vibrating up and down in synchronization with the input vibration, a gap is formed between the movable plate 94 and the top plate portion 78 and the bottom plate portion 90, so that the main portion passes through the openings 88 and 92 and the storage chamber 80. Since the liquid flows between the liquid chamber 56 and the sub liquid chamber 58, an increase in the dynamic spring constant accompanying an increase in the liquid pressure in the main liquid chamber 56 can be suppressed, and even when such high-frequency vibration is input. Maintaining low dynamic spring constant of the sexual body 16 can be effectively absorbed high frequency vibrations by elastic deformation of the elastic body 16.

  In the vibration isolator 10 according to this embodiment, since the movable plate 94 is formed of a rubber composition containing oleic acid as a lubricating component, the surface of the movable plate 94 has oleic acid over a long period of time. Gradually oozing (blooming) onto the rubber surface, and this oleic acid acts as a self-lubricant, so that the movable plate 94 and the inner peripheral surface of the storage chamber 80 and the top plate when the movable plate 94 moves in the storage chamber 80 The friction coefficient with the part 78 and the baseplate part 90 can be reduced significantly.

  As a result, according to the vibration isolator 10 according to the present embodiment, when the vibration is input from the engine or the vehicle body side and the movable plate 94 vibrates along the amplitude direction of the input vibration, the movable plate 94 has its outer peripheral surface. Even if the movable plate 94 is repeatedly brought into pressure contact with the top plate portion 78 and the bottom plate portion 90 in the storage chamber 80, the movable plate 94 moves from the movable plate 94 to the inner peripheral surface of the storage chamber 80. The lubricating action of the oleic acid that exudes causes the frictional resistance between the movable plate 94 and the inner peripheral surface of the storage chamber 80 and the top plate portion 78 and the bottom plate portion 90 to be sufficiently small. It is possible to effectively prevent the generation of squeaking noise caused by sliding contact with the surface and the squeaking noise generated when the movable plate 94 is pressed against the top plate portion 78 and the bottom plate portion 90.

  In the vibration isolator 10 according to the present embodiment described above, a disc-shaped member having a substantially constant thickness at an arbitrary position along the radial direction is used as the movable plate 94 stored in the storage chamber 80. However, instead of such a movable plate 94, for example, as shown in FIG. 3, a movable plate 100 whose thickness gradually increases from the outer peripheral side toward the central portion may be applied. . The movable plate 100 is formed in a substantially convex lens shape in which the front surface portion and the back surface portion along the thickness direction are each formed of a convex curved surface (spherical surface). It is substantially plane symmetric. Here, the thickness at the center of the movable plate 100 is thicker than the thickness along the axial direction of the storage chamber 80. Thereby, the movable plate 100 accommodated in the storage chamber 80 is sandwiched in a state where the central portion is compressed along the axial direction between the top plate portion 78 of the partition fitting 50 and the bottom plate portion 90 of the partition member 48. Then, the outer peripheral side bent portion 96 is separated from the outer fitting portion 74 and the bottom plate portion 90 along the axial direction with respect to the center portion.

  The outer diameter of the movable plate 100 is slightly smaller than the inner diameter of the storage chamber 80 or substantially equal to the inner diameter of the storage chamber 80. Thereby, in the state in which the movable plate 100 is housed in the housing chamber 80, the bending portion 96 extends along the axial direction with the vicinity of the center portion pressed against the top plate portion 78 and the bottom plate portion 90 as a fulcrum (swing center). It is supported so as to swing up and down. Further, the outer peripheral end of the movable plate 100 extends to the outer peripheral side from the outer peripheral ends of the opening 92 of the bottom plate 90 and the opening 88 of the partition member 50.

  When vibration is input from the engine or the vehicle body side, the movable plate 100 swings slightly in the storage chamber 80 with the vicinity of the center portion as a fulcrum, and the bending portion 96 is accompanied by a change in the hydraulic pressure in the main liquid chamber 56. It bends up and down along the axial direction. At this time, the bending portion 96 is bent and deformed up and down in synchronization with the change in the hydraulic pressure in the main liquid chamber 56 in the storage chamber 80, and at the same time, contacts the top plate portion 78 in the partition fitting 50 and the bottom plate portion 90 in the partition member 48. Repeat the contact and separation.

  Also in the vibration isolator 10 using the movable plate 100 shown in FIG. 3, the bending portion 96 that bends and deforms in synchronization with the change in the hydraulic pressure in the main liquid chamber 56 has the top plate portion 78 of the partition metal 50 and the bottom plate of the partition member 48. When the operation of contacting and separating from the portion 90 is repeated, a gap having a width corresponding to the amount of deflection is formed between the outer peripheral end of the movable plate 94 and the inner peripheral surface of the storage chamber 80. A phenomenon may occur in which the liquid flows between the main liquid chamber 56 and the sub liquid chamber 58 through the portions 88 and 92. On the other hand, in the vibration isolator 10, if the bending portion 96 that bends and deforms in synchronization with the change in the hydraulic pressure in the main liquid chamber 56 comes into close contact with one of the top plate portion 78 of the partition fitting 50 and the bottom plate portion 90 of the partition member 48, the bending is performed. Since one of the opening 92 and the opening 88 is closed by the portion 96 and the storage chamber 80 is closed, the liquid flows between the main liquid chamber 56 and the sub liquid chamber 58 through the storage chamber 80. This is substantially prevented.

  Therefore, as in the case of the movable plate 94, if the substantially convex lens-shaped movable plate 100 is formed of a rubber composition containing oleic acid or the like as a lubricant, the bending portion of the movable plate 94 when vibration is input from the engine or the vehicle body side. 96 is bent up and down in the storage chamber 80, and the sag generated when the bent portion 96 of the movable plate 94 is pressed against the bottom plate portion 90 of the partition member 48 and the top plate portion 78 of the partition member 50 in synchronization with the bending deformation. The sound pressure and the sound pressure of the squeaking noise that occurs when the movable plate 100 swings in a state where the central portion is pressed against the top plate portion 78 and the bottom plate portion 90 can be effectively reduced.

It is sectional drawing which shows the structure of the vibration isolator which concerns on the 1st Embodiment of this invention. It is the side sectional view and perspective view which show the structure of the partition member and partition metal fitting which accommodated the movable plate shown by FIG. It is side surface sectional drawing which shows the other example of the movable plate in the vibration isolator which concerns on the 1st Embodiment of this invention.

Explanation of symbols

10 Anti-vibration device 12 Inner tube bracket (mounting member)
14 Outer cylinder fitting (mounting member)
16 Elastic body 48 Partition member 50 Partition bracket (partition member)
54 Diaphragm 56 Main liquid chamber 58 Sub liquid chamber 66 Orifice (restricted passage)
78 Top plate (opening edge)
80 storage room 88 opening 90 bottom plate (opening edge)
92 Opening 94 Movable plate 100 Movable plate

Claims (4)

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 a liquid is enclosed, and the internal volume changes with deformation of the elastic body with the elastic body as a part of the partition;
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 and the sub liquid chamber are partitioned, a hollow storage chamber is provided therein, and an opening for communicating the storage chamber with the main liquid chamber and the sub liquid chamber is formed. A partition member;
A restricting passage communicating the main liquid chamber and the sub liquid chamber;
A gap of a predetermined dimension is formed between the opening and the opening peripheral edge of the partition member, the first opening or the opening being disposed so as to restrict the flow of liquid in the storage chamber. A movable plate that vibrates within the gap when the vibration is input to the mounting member, and is in contact with and separated from the peripheral edge of the opening in synchronization with the vibration;
An anti-vibration device having
A vibration isolator comprising the movable plate made of a self-lubricating rubber composition having self-lubricating properties.   2. The vibration isolator according to claim 1, wherein the movable plate is formed of a rubber composition to which oleic acid is added as a lubricating component.   The vibration isolator according to claim 2, wherein the rubber composition has an oleic acid content of 0.2 wt% to 3 wt%. The movable plate is formed in a substantially convex lens shape whose front and back surfaces along the thickness direction are respectively convex curved surfaces, and the center portion of the front and back surfaces of the movable plate is pressed against the inner wall surface of the partition member, respectively. To store in the storage room,
At the time of vibration input to the first or second mounting member, a bending region on the outer peripheral side with respect to the central portion that is in pressure contact with the inner wall surface of the storage chamber in front of the movable plate in synchronization with the vibration input is the peripheral edge of the opening The vibration isolator according to claim 1, 2 or 3, wherein the vibration isolator is in contact with or separated from the portion.

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