JP2007010102A - Vibration absorbing device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a vibration absorbing device for effectively suppressing the loss of pumping force during inputting vibration of predetermined frequency and liquid pressure rise in a main liquid chamber during inputting vibration of higher frequency than the predermined frequency. <P>SOLUTION: In the vibration absorbing device 10, when the frequency of input vibration is higher than a predetermined value and its amplitude is smaller, an orifice 66 is put into a clogged condition to cause liquid to hardly flow in the orifice 66. However, because of a small change in the inner capacity of the main liquid chamber 56 during expansion/contraction with the input vibration, the maximum expansion amount of a membrane sheet 90 (an expansion/contraction chamber 94) relative to the inner capacity of the main liquid chamber 56 is set to be not smaller than the contraction amount of the inner capacity of the main liquid chamber 56 with the elastic body 16, whereby the liquid pressure rise in the main liquid chamber 56 due to the elastic deformation of the elastic body 16 is absorbed by the membrane sheet 90. This suppresses the rise of a dynamic spring constant with the liquid pressure rise in the main liquid chamber 56, keeps the dynamic spring constant of the elastic body 16 low during inputting such high frequency vibration, and effectively absorbs the high frequency vibration with the elastic deformation of the elastic body 16. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a vibration isolator that is applied to, for example, an automobile, a general industrial machine, and the like and attenuates and absorbs vibration 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 is disposed as an anti-vibration device between the engine and the vehicle body (frame). The engine mount absorbs vibration energy by elastic deformation of the rubber elastic body, and suppresses transmission of vibration from the engine to the frame side. 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 damped and absorbed by the viscous resistance of the liquid.

In a liquid-filled vibration isolator applied as an engine mount as described above, when the frequency of input vibration is higher than the resonance frequency of the orifice, the orifice becomes clogged and the hydraulic pressure in the main liquid chamber increases. As a result, the dynamic spring constant increases. For this reason, in such a vibration isolator, a part of the partition wall of the main liquid chamber is constituted by a rubber membrane, and when high frequency vibration exceeding the resonance frequency is input, the rubber membrane is elastically deformed by the liquid pressure in the main liquid chamber. There is one that suppresses an increase in the fluid pressure in the main fluid chamber (Patent Document 1). However, in the vibration isolator having such a structure, the rubber membrane is elastically deformed by the liquid pressure in the main liquid chamber even when vibration is input at the resonance frequency, so that the liquid flows between the main liquid chamber and the sub liquid chamber. There is a problem that a loss occurs in the pumping force to reduce the attenuation obtained by liquid column resonance.
JP-A-6-185572

  In view of the above fact, the object of the present invention is to effectively suppress the loss of the pump force when a vibration is input at a predetermined frequency and the increase in the fluid pressure in the main liquid chamber when the vibration is input at a frequency higher than the predetermined frequency. May provide anti-vibration devices.

  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 And another part of the partition wall of the main liquid chamber are formed, and elastically deformed in a volume expansion / contraction direction that expands / contracts the main liquid chamber according to a change in the liquid pressure of the main liquid chamber An anti-vibration device having a membrane member, wherein the membrane member is in a tension direction. It is composed of a non-stretchable sheet-like material, and at least a part of the membrane member is held in a state of being bent in a continuous wave shape or bellows shape, and can be elastically deformed in the volume expansion / contraction direction. An enlarged / reduced portion is formed.

  In the vibration isolator according to the first aspect, the membrane part forming the other part of the partition wall of the main liquid chamber is made of a sheet-like material having non-stretchability in the tension direction, and at least part of the membrane member By forming the expansion / contraction portion that is held in a wave-like or bellows-shaped state, the expansion / contraction portion of the membrane member expands / contracts the internal volume of the main liquid chamber in accordance with the change in the liquid pressure in the main liquid chamber. When the main liquid chamber contracts due to elastic deformation of the elastic body, the expansion / contraction part of the membrane member elastically deforms so as to expand the internal volume of the main liquid chamber, and the expansion / contraction part of the membrane member The hydraulic pressure in the main liquid chamber is prevented from rising within a range corresponding to the maximum expansion amount due to

  Further, in the vibration isolator according to claim 1, since the membrane member is made of a non-stretchable sheet-like material, the expansion / contraction portion of the membrane member is expanded in a wave shape or a bellows shape (deflection). When the main liquid chamber is deformed in the expansion direction as much as possible and the internal volume of the main liquid chamber is expanded by a predetermined amount, the membrane member is not elastically deformed in the expansion direction, and the expansion of the main liquid chamber by the membrane member is stopped.

  Therefore, in the vibration isolator according to claim 1, when the frequency of the input vibration is lower than the predetermined value and the amplitude thereof is large, the range of change when the internal volume of the main liquid chamber is expanded or contracted by the input vibration is large. Therefore, if the maximum expansion amount of the membrane member is set sufficiently small with respect to the change width of the inner volume of the main liquid chamber, the membrane member against the change in the hydraulic pressure in the main liquid chamber caused by the elastic deformation of the elastic body. The liquid pressure loss in the main liquid chamber caused by the expansion of the main liquid chamber is made sufficiently small, and the change of the liquid pressure in the main liquid chamber by this elastic body is used as a pumping force to allow the liquid to flow between the main liquid chamber and the sub liquid chamber through the restriction passage. Since it can be circulated, the input vibration can be effectively absorbed by the viscous resistance of the liquid flowing in the restricted passage.

  In particular, when the frequency of the input vibration substantially matches the resonance frequency of the restriction passage, the resonance phenomenon (liquid column resonance) occurs in the liquid flowing between the main liquid chamber and the sub liquid chamber through the restriction passage. As a result, the input vibration of the resonance frequency can be effectively damped by the action of the liquid column resonance.

  In the vibration isolator according to the first aspect, when the frequency of the input vibration is higher than a predetermined value and the amplitude is small, the restriction passage is clogged and the liquid does not easily flow through the restriction passage. Because the change range of the internal volume of the main liquid chamber when expanding or contracting due to input vibration is small, the maximum expansion amount of the membrane member can be set to be equal to or greater than the reduction amount of the internal volume of the main liquid chamber by the elastic body. For example, the increase in the hydraulic pressure in the main liquid chamber caused by the elastic deformation of the elastic body can be absorbed by the membrane member, so that the increase of the dynamic spring constant accompanying the increase in the hydraulic pressure in the main liquid chamber can be suppressed. Even during input, the dynamic spring constant of the elastic body is kept low, and high-frequency vibrations can be effectively absorbed by elastic deformation of the elastic body.

  A vibration isolator according to claim 2 of the present invention is the vibration isolator according to claim 1, further comprising a partition member that partitions the main liquid chamber and the sub liquid chamber. A membrane member is provided.

  The vibration isolator according to claim 3 of the present invention is the vibration isolator according to claim 1, wherein an air chamber is provided on the opposite side of the main liquid chamber via the membrane member.

  The vibration isolator according to claim 4 of the present invention is the vibration isolator according to any one of claims 1 to 3, wherein the sheet material constituting the membrane member is impermeable to liquid. It is characterized by.

  The vibration isolator according to claim 5 of the present invention is the vibration isolator according to any one of claims 1 to 4, wherein the sheet material constituting the membrane member is a woven fabric woven with resin fibers. It was formed by.

  The vibration isolator according to claim 6 of the present invention is the vibration isolator according to claim 5, wherein the woven fabric is subjected to water repellent finish.

  The vibration isolator according to claim 7 of the present invention is the vibration isolator according to any one of claims 1 to 6, wherein the membrane member has a maximum elongation of 10% or less along the tension direction. It is characterized by that.

  As described above, according to the vibration isolator of the present invention, the pumping force loss at the time of vibration input at a predetermined frequency and the increase in the liquid pressure in the main liquid chamber at the time of vibration input at a frequency higher than the predetermined frequency are effective. Can be suppressed.

Hereinafter, a vibration isolator according to an embodiment of the present invention will be described with reference to the drawings.
(First embodiment)
FIG. 1 shows a vibration isolator according to a first 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 a vehicle such as 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. And a substantially thin 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. The outer tube fitting 14 is formed with an enlarged diameter portion 20 having a diameter larger than that of the lower end portion at the upper end portion with respect to the step portion 18 provided at the axially intermediate portion thereof. In addition, the outer tubular metal fitting 14 is formed with a tapered portion 22 whose diameter decreases in a tapered manner downward at the lower end portion thereof, and is bent 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 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 91 formed in the bottom plate portion of the connection cylinder 26, and an engine 34 is connected to the lower end portion of the inner cylinder fitting 12 by a bolt 34. The base end portion of the connecting 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. The base end portion of the bracket 36 is covered with a stopper rubber 38 formed in a tube shape, 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 the occurrence of a collision sound is also prevented 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 upper end portion on the outer peripheral side, and this covering portion 46 is formed on the upper end side on the inner peripheral surface of the outer cylinder fitting 14. It is vulcanized and bonded to cover the upper end side of 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. 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 tube fitting 14 into which the partition member 48, the partition fitting 50 and the support tube 52 are inserted, the caulking portion 24 is bent in a tapered shape 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 the shape of a ridge that protrudes upward 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. This liquid chamber space is formed by the partition member 48 and the partition fitting 50. 16 is divided into a main liquid chamber 56 having a partition wall as a part of a partition wall and a sub liquid chamber 58 having a diaphragm 54 as a part of a 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 can be deformed so as to expand and contract the internal volume. 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. 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.

  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. Here, 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 opening 70 is formed in the central portion of the thick portion 68 so as to penetrate in the axial direction. ing. Further, 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. In the escape portion 72, the upper end portions of the extension fitting 40 and the elastic body 16 are inserted while leaving a gap between the lower surface of the thick portion 68 along the axial direction. Here, the gap between the lower surface of the thick portion 68 and the upper surface portion of the extension fitting 40 and the elastic body 16 is a state in which the engine is connected to the bracket 36 and a load resulting from the weight of the engine is input to the bracket 36. Then, since it is enlarged from the illustrated state to a sufficient width, the extension fitting 40 and the elastic body 16 do not contact the lower surface of the thick portion 68 even if vibration is input.

  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. A circular opening 78 is formed at the center of the outer fitting part 74 so as to face the opening 70 of the partition member 48. The inner diameter of the opening 78 is substantially the same as the inner diameter of the opening 70.

  As shown in FIG. 2B, the thickness between the thick portion 68 of the partition member 48 and the external fitting portion 74 of the partition member 50 is substantially so as to close the opening 70 and the opening 78. A membrane sheet 90 formed in a certain sheet shape is disposed. The membrane sheet 90 is formed in a disk shape having a diameter larger than the inner diameter of the openings 70 and 78.

The peripheral edge portion 92 is sandwiched in a pressurized state between the upper surface outer peripheral portion of the thick portion 68 and the lower surface outer peripheral portion of the outer fitting portion 74 over the entire circumference, and between the thick portion 68 and the outer fitting portion 74. It is fixed to. Thus, the membrane sheet 90 is stretched by the thick portion 68 and the outer fitting portion 74 so as to close the openings 70 and 78 by the inner peripheral side portion excluding the peripheral edge portion 92.

  The membrane sheet 90 is made of a non-stretchable sheet material having a constant thickness. As such a sheet-like material, for example, a material obtained by molding a resin material such as nylon (trade name), silicon, vinyl chloride, or polypropylene into a sheet shape can be used. In particular, nylon (trade name) and silicon are suitable as molding materials for sheet-like materials because they have flexibility and high durability. Further, the mechanical strength of the sheet-like material (membrane sheet 90) may be increased by dispersing high-strength fibers such as aramid fibers and carbon fibers in these resin materials.

  Further, as another sheet-like material that can be processed into the membrane sheet 90, for example, a woven fabric woven with resin fibers of nylon (trade name), silicon, vinyl chloride, polypropylene, and aramid fibers may be used.

  However, since the membrane sheet 90 needs to be highly impermeable to the liquid in the main liquid chamber 56 and the sub liquid chamber 58, when using a woven fabric woven with resin fibers, at least one side of the woven fabric is used. It is preferable to apply a water-repellent treatment to the surface of this. The water-repellent finishing method includes hydrophobizing the fiber itself to impart water repellency to the woven fabric, applying or coating a material having high water repellency to the woven fabric surface, and resin on the surface of the woven fabric. Various known methods such as a method for forming a water-repellent layer made of a material, a rubber composition, and the like can be used.

  The sheet material processed into the membrane sheet 90 preferably has an expansion / contraction rate (maximum value) of 10% or less along the tension direction. Here, the expansion / contraction rate along the tension direction is the maximum elongation rate along the one direction within the elastic range when a tensile load is applied to the sheet-like material along any one direction in the plane direction. It is.

  As shown in FIG. 2, the membrane sheet 90 has an expansion / contraction portion that is elastically deformable in a volume expansion / contraction direction (= axial direction) in which the inner peripheral side of the peripheral portion 92 expands / contracts the internal volume of the main liquid chamber 56. 94. The expansion / contraction part 94 is provided with a large number of folds extending linearly along the extending direction (arrow E direction) coinciding with the radial direction of the sheet-like material. It arrange | positions at the substantially constant pitch along the expansion-contraction direction (arrow S direction) orthogonal to a direction. The expansion / contraction portions 94 are alternately bent upward and downward along the fold. Thus, between the nth and (n + 2) th (where n is a natural number of 1 or more) folds from one end of the expansion / contraction part 94, a bellows part 96 having a V-shaped cross section (see FIG. 2 (B)) is formed continuously.

  When the expansion / contraction part 94 is pressurized from the main liquid chamber 56 side, each bellows part 96 is elastically deformed in the direction of opening its cross section around the fold, as shown by a two-dot left chain line, The inner volume of the main liquid chamber 56 is expanded by being deformed so as to curve upward. At this time, as shown in FIG. 2A, when the expansion / contraction part 94 is opened until each bellows part 96 has a substantially flat plate shape, the sheet material itself has non-stretchability. Even if the applied pressure (fluid pressure) from the inside rises, the amount of deformation in the expansion direction of the main fluid chamber 56 substantially stops.

  Further, when the hydraulic pressure from the main liquid chamber 56 side is lowered from the state indicated by the two-dot chain line, the expansion / contraction portion 94 is convex upward by restoring each bellows portion 96 in the direction of closing the cross section. The inner volume of the main liquid chamber 56 is reduced by restoring the curved shape so as to approach the substantially flat shape indicated by the solid line.

  In this embodiment, the bellows portion 96 having a V-shaped cross section is continuously formed in the expansion / contraction portion 94. However, the expansion / contraction portion 94 has a cross-sectional shape along a sine curve or a semicircular locus, that is, a wave shape. A plurality of bellows portions 96 may be continuously formed so as to be elastically deformable in the direction of volume expansion / contraction. In the expansion / contraction portion 94, it is not always necessary to form folds linearly along the radial direction. For example, even if a large number of folds are formed concentrically, along the two directions substantially orthogonal to each other, That is, a large number of folds are formed in a lattice shape, and a bellows portion is continuously formed in the expansion / contraction portion 94 by alternately bending the sheet-like material (expansion / contraction portion 94) upward and downward along these folds. The sheet-like material may be curved in a wave shape at a portion corresponding to such a fold.

  Next, the operation and action of the vibration isolator 10 according to the embodiment of the present invention configured as described above will be described. In the vibration isolator 10, at the time of vibration input from the engine or the vehicle body side, the elastic body 16 that is the main vibration absorber is elastically deformed by this vibration. Thereby, the input vibration is attenuated and absorbed by the internal friction of the elastic body 16 or the like.

  In the vibration isolator 10, the membrane sheet 90 forming a part of the partition wall of the main liquid chamber 56 is made of a sheet-like material that is non-stretchable in the tension direction, and the main liquid chamber 56 and the auxiliary liquid in the membrane sheet 90 are formed. The expansion / contraction portions that are elastically deformable in the volume expansion / contraction direction of the main liquid chamber 56 are formed in the central portions facing the chambers 58, so that the expansion / contraction portions 94 of the membrane sheet 90 are in the main liquid chamber 56. As the fluid pressure changes, the inner volume of the main liquid chamber 56 is elastically deformed so as to expand and contract. When the main liquid chamber 56 contracts due to the elastic deformation of the elastic body 16, the expansion / contraction section 94 is connected to the main liquid chamber 56. It elastically deforms toward the secondary liquid chamber 58 so as to expand the internal volume, and prevents the liquid pressure in the main liquid chamber 56 from rising within a range corresponding to the maximum expansion amount by the expansion / contraction part 94.

  In the vibration isolator 10, since the membrane sheet 90 is made of a non-stretchable sheet-like material, the expansion / contraction portion 94 of the membrane sheet 90 extends in the expansion direction until the deformation (deflection) of the bellows portion 96 is fully extended. When the inner volume of the main liquid chamber 56 is expanded by a predetermined amount, elastic deformation in the expansion direction of the membrane sheet 90 does not occur, and expansion of the main liquid chamber 56 by the membrane sheet 90 stops.

  Therefore, in the vibration isolator 10, when the frequency of the input vibration is lower than the predetermined value and the amplitude thereof is large, the change width when the internal volume of the main liquid chamber 56 is expanded or contracted by the input vibration is large. If the maximum expansion amount of the membrane sheet 90 with respect to the internal volume of the main liquid chamber 56 is set sufficiently small with respect to the change width of the internal volume of the main liquid chamber 56, the main liquid chamber 56 generated by the elastic deformation of the elastic body 16 is set. The fluid pressure loss in the main fluid chamber 56 due to the expansion of the membrane sheet 90 with respect to the fluid pressure change in the inside is sufficiently reduced, and the fluid pressure change in the main fluid chamber 56 due to the elastic body 16 is pumped through the orifice 66 as a main force. Since the liquid can flow between the liquid chamber 56 and the sub liquid chamber 58, the input vibration can be effectively absorbed by the viscous resistance of the liquid flowing through the orifice 66.

In particular, when the input vibration is a shake vibration, a resonance phenomenon (liquid column resonance) occurs in the liquid flowing between the main liquid chamber 56 and the sub liquid chamber 58 through the orifice 66. The input vibration of the shake vibration can be effectively damped by the action of resonance.
In the vibration isolator 10 according to the present embodiment, in addition to input vibration (low frequency vibration) having a frequency lower than a predetermined value and large amplitude, vibration in a frequency range higher than the low frequency vibration (high frequency vibration). ) Are input at the same time, or when high-order components (secondary components, tertiary components...) Of low-frequency vibrations are input, Since the increase in fluid pressure can be absorbed by the membrane sheet 90, when high-frequency vibration and higher-order components are input together with low-frequency vibration, it is also effective that the dynamic spring constant of the device increases due to the input of high-frequency vibrations and higher-order components. Can be prevented.

  In the vibration isolator 10, when the frequency of the input vibration is higher than a predetermined value and the amplitude is small, the orifice 66 becomes clogged and it is difficult for the liquid to flow through the orifice 66. Since the change width of the internal volume of the main liquid chamber 56 during expansion / contraction is small, the maximum expansion amount of the membrane sheet 90 with respect to the internal volume of the main liquid chamber 56 is equal to or greater than the reduction amount of the internal volume of the main liquid chamber 56 by the elastic body 16. If it is set to be, the increase in the fluid pressure in the main fluid chamber 56 caused by the elastic deformation of the elastic body 16 can be absorbed by the membrane sheet 90. Therefore, the dynamic spring constant associated with the fluid pressure increase in the main fluid chamber 56 is increased. The rise can be suppressed, and the dynamic spring constant of the elastic body 16 can be kept low even when such high-frequency vibration is input, and high-frequency vibration can be effectively absorbed by elastic deformation of the elastic body 16 or the like.

  In the vibration isolator 10, since the increase in the liquid pressure in the main liquid chamber 56 at the time of inputting high frequency vibration is prevented by the membrane sheet 90 made of a sheet-like material, a plurality of components are synchronized with the input vibration inside the apparatus. Since they do not collide with each other, it is possible to reliably prevent abnormal noise such as hitting sound from the inside of the apparatus during vibration input.

  In the vibration isolator 10, the sheet material constituting the membrane sheet 90 is subjected to water repellency, or the sheet material itself is impermeable to the liquid. When the flow between the liquid chamber 56 and the sub liquid chamber 58 is reliably prevented and the frequency of the input vibration is lower than a predetermined value and the amplitude thereof is large, the inside of the main liquid chamber 56 is passed through the membrane sheet 90. It is possible to reliably prevent the liquid from flowing out into the auxiliary liquid chamber 58 and reducing the pumping force.

(Second Embodiment)
FIG. 3 shows a vibration isolator according to the second embodiment of the present invention. Similar to the vibration isolator 10 according to the first embodiment, the vibration isolator 100 is applied as an engine mount that supports an engine that is a vibration generating unit in a vehicle such as an automobile to a vehicle body that is a vibration receiving unit. It is. Note that in the vibration isolator 100 according to the present embodiment, the same parts as those of the vibration isolator 10 according to the first embodiment are denoted by the same reference numerals, and description thereof is omitted.

  The vibration isolator 100 according to the present embodiment is different from the vibration isolator 10 according to the first embodiment in that the top of the extension fitting 40 embedded in the elastic body 16 and the lower surface side of the flange member 42. An auxiliary membrane sheet 102 is disposed therebetween, and an air chamber 108 is formed on the elastic body 16 so as to face the auxiliary membrane sheet 102.

  In the vibration isolator 10 according to the first embodiment, when the frequency of the input vibration is higher than a predetermined value and the amplitude thereof is small, the maximum expansion amount with respect to the inner volume of the main liquid chamber 56 of the membrane sheet 90 is set as an elastic body. 16, the increase in the hydraulic pressure in the main liquid chamber 56 caused by the elastic deformation of the elastic body 16 was absorbed by the membrane sheet 90 by setting it to be equal to or greater than the change width of the internal volume of the main liquid chamber 56 due to 16. When the outer diameter of the membrane sheet 90 (expansion / contraction part 94) and the elastic deformation amount of the expansion / contraction part 94 cannot be sufficiently increased, the maximum expansion amount of the membrane sheet 90 with respect to the internal volume of the main liquid chamber 56 is set to the main liquid by the elastic body 16. There is also a possibility that it may not be possible to set a value larger than the change width of the internal volume of the chamber 56.

  Therefore, in the vibration isolator 100 according to the second embodiment, the auxiliary membrane sheet 102 is additionally disposed in the main liquid chamber 56, whereby the maximum expansion amount of the membrane sheet 90 with respect to the internal volume of the main liquid chamber 56 is set to an elastic body. Even when the internal volume of the main liquid chamber 56 cannot be set to be larger than the change width of the main liquid chamber 56 due to 16, the content of the main liquid chamber 56 is reduced by both the membrane sheet 90 and the auxiliary membrane sheet 102 when the main liquid chamber 56 is reduced by the elastic body 16. Extend the product.

  The auxiliary membrane sheet 102 is provided with a peripheral edge 104 sandwiched between the top of the extension fitting 40 and the lower surface side of the flange member 42, and an expansion / contraction part 106 is provided on the inner peripheral side of the peripheral edge 104. It has been. The structure and shape of the auxiliary membrane sheet 102 are basically the same as the membrane sheet 90 according to the first embodiment. Accordingly, the expansion / contraction portion 106 of the auxiliary membrane sheet 102 can be deformed so as to expand / contract the internal volume of the main liquid chamber 56 in accordance with the change in the hydraulic pressure of the main liquid chamber 56.

  The elastic body 16 has a trapezoidal concave section 107 whose inner diameter narrows downward at the center of the top surface. The concave section 107 is formed by the expansion / contraction section 106 of the auxiliary membrane sheet 102 on the upper surface side. It is blocked. Thus, an air chamber 108 is provided on the top side of the elastic body 16, with the recess 107 as an inner wall and the expansion / contraction portion 106 as a partition wall between the main liquid chamber 56. The air chamber 108 allows the expansion / contraction portion 106 to be deformed in the expansion direction, as indicated by a two-dot chain line.

  In the vibration isolator 100 according to the present embodiment configured as described above, when the frequency of the input vibration is lower than a predetermined value and the amplitude is large, the internal volume of the main liquid chamber 56 is expanded or contracted by the input vibration. Therefore, the maximum expansion amount of the membrane sheet 90 and the auxiliary membrane sheet 102 with respect to the internal volume of the main liquid chamber 56 is set to be sufficiently small with respect to the change width of the internal volume of the main liquid chamber 56. In this case, the hydraulic pressure loss in the main liquid chamber 56 due to the expansion of the membrane sheet 90 and the auxiliary membrane sheet 102 with respect to the change in the hydraulic pressure in the main liquid chamber 56 caused by the elastic deformation of the elastic body 16 is sufficiently reduced. The liquid can be circulated between the main liquid chamber 56 and the sub liquid chamber 58 through the orifice 66 by using the change in the liquid pressure in the main liquid chamber 56 by the body 16 as a pumping force. Input vibration due to the viscosity resistance of the liquid flowing in the scan 66 can be effectively absorbed.

  In particular, when the input vibration is a shake vibration, a resonance phenomenon (liquid column resonance) occurs in the liquid flowing between the main liquid chamber 56 and the sub liquid chamber 58 through the orifice 66. The input vibration of the shake vibration can be effectively damped by the action of resonance.

  Further, in the vibration isolator 100, when the frequency of the input vibration is higher than a predetermined value and the amplitude is small, the orifice 66 becomes clogged and it is difficult for the liquid to flow through the orifice 66.

  At this time, even if the maximum expansion amount of the membrane sheet 90 with respect to the internal volume of the main liquid chamber 56 cannot be set to be greater than or equal to the change width of the internal volume of the main liquid chamber 56 by the elastic body 16, the shortage is caused by the auxiliary membrane sheet 102. Since the expansion of the main liquid chamber 56 can compensate, the sum of the maximum expansion amount of the membrane sheet 90 with respect to the internal volume of the main liquid chamber 56 and the maximum expansion amount of the auxiliary membrane sheet 102 with respect to the internal volume of the main liquid chamber 56 is 16, the increase in the hydraulic pressure in the main liquid chamber 56 caused by elastic deformation of the elastic body 16 is caused by the membrane sheet 90 and the auxiliary membrane sheet 102. Since it can be absorbed reliably, an increase in the dynamic spring constant associated with an increase in the hydraulic pressure in the main liquid chamber 56 can be suppressed, and an elastic body can be used even when such high-frequency vibration is input. The dynamic spring constant of 6 and kept low, can effectively absorb the high frequency vibration by the elastic deformation of the elastic body 16.

(Third embodiment)
FIG. 4 shows a vibration isolator according to a third embodiment of the present invention. The vibration isolator 110 is an engine mount that supports an engine that is a vibration generating unit in a vehicle such as an automobile to a vehicle body that is a vibration receiving unit, similarly to the vibration isolators 10 and 100 according to the first and second embodiments. As applied. Note that in the vibration isolator 110 according to the present embodiment, the same parts as those in the vibration isolator 10 according to the first embodiment are denoted by the same reference numerals and description thereof is omitted.

  The vibration isolator 110 according to the present embodiment is different from the vibration isolator 10 according to the first embodiment in that a circular opening 112 facing the main liquid chamber 56 on the peripheral wall portion and the covering portion 46 of the outer cylinder fitting 14. The auxiliary membrane sheet 122 is disposed so as to close the opening 112, and the cover member 114 that forms the air chamber 116 is provided outside the auxiliary membrane sheet 122.

  In the vibration isolator 100 according to the second embodiment, the air chamber 108 adjacent to the main liquid chamber 56 via the auxiliary membrane sheet 102 is a closed space that does not communicate with the outside (atmospheric space). When the membrane sheet 90 is deformed in the expansion direction, there is a disadvantage that the expansion of the membrane sheet 90 is suppressed due to the compressed resistance of the air in the air chamber 108.

  Therefore, in the vibration isolator 110 according to the third embodiment, by providing the air chamber 116 that communicates with the atmospheric space outside the auxiliary membrane sheet 122, the auxiliary membrane sheet 122 extends in the expansion direction with respect to the internal volume of the main liquid chamber 56. It is easy to deform.

  In the cover member 114 formed in a substantially bottomed cylindrical shape, a flange portion 118 extending to the outer peripheral side is bent at the end on the opening side, and the air chamber 116 communicates with the outside at the center of the bottom plate. A vent hole 120 is formed.

  The auxiliary membrane sheet 122 is annularly provided with a peripheral edge 124 that is sandwiched between the outer peripheral surface of the outer cylinder fitting 14 and the flange 118 of the cover member 114, and an expansion / contraction part is provided on the inner peripheral side of the peripheral edge 124. 126 is provided. The structure and shape of the auxiliary membrane sheet 122 are basically the same as the membrane sheet 90 according to the first embodiment. Therefore, the expansion / contraction portion 126 of the auxiliary membrane sheet 122 can be deformed so as to expand / contract the internal volume of the main liquid chamber 56 according to the change in the hydraulic pressure of the main liquid chamber 56.

  In the vibration isolator 110, the flange portion 118 of the cover member 114 is fixed to the outer peripheral surface of the outer cylindrical metal member 14 via the peripheral edge portion 124 of the auxiliary membrane sheet 122. As a result, the inner peripheral side of the cover member 114 is closed by the expansion / contraction portion 126 of the auxiliary membrane sheet 122, and an air chamber 116 communicating with the outside (atmospheric space) through the vent hole 120 is formed. The air chamber 116 allows the expansion / contraction part 126 to be deformed in the expansion direction, as indicated by a two-dot chain line.

  In the vibration isolator 110 according to this embodiment configured as described above, when the frequency of the input vibration is lower than a predetermined value and the amplitude is large, the internal volume of the main liquid chamber 56 is expanded or contracted by the input vibration. Therefore, the maximum expansion amount of the membrane sheet 90 and the auxiliary membrane sheet 122 with respect to the internal volume of the main liquid chamber 56 is set sufficiently small with respect to the change width of the internal volume of the main liquid chamber 56. In this case, the hydraulic pressure loss in the main liquid chamber 56 due to the expansion of the membrane sheet 90 and the auxiliary membrane sheet 122 with respect to the change in the hydraulic pressure in the main liquid chamber 56 caused by the elastic deformation of the elastic body 16 is sufficiently reduced. The liquid can be circulated between the main liquid chamber 56 and the sub liquid chamber 58 through the orifice 66 by using the change in the liquid pressure in the main liquid chamber 56 by the body 16 as a pumping force. Input vibration due to the viscosity resistance of the liquid flowing in the scan 66 can be effectively absorbed.

  In particular, when the input vibration is a shake vibration, a resonance phenomenon (liquid column resonance) occurs in the liquid flowing between the main liquid chamber 56 and the sub liquid chamber 58 through the orifice 66. The input vibration of the shake vibration can be effectively damped by the action of resonance.

  Further, in the vibration isolator 100, when the frequency of the input vibration is higher than a predetermined value and the amplitude is small, the orifice 66 becomes clogged and it is difficult for the liquid to flow through the orifice 66.

  At this time, even if the maximum expansion amount of the membrane sheet 90 with respect to the internal volume of the main liquid chamber 56 cannot be set to be greater than or equal to the change width of the internal volume of the main liquid chamber 56 by the elastic body 16, the shortage is compensated by the auxiliary membrane sheet 122. Since the expansion of the main liquid chamber 56 can compensate, the sum of the maximum expansion amount of the membrane sheet 90 with respect to the internal volume of the main liquid chamber 56 and the maximum expansion amount of the auxiliary membrane sheet 122 with respect to the internal volume of the main liquid chamber 56 is 16, the increase in the fluid pressure in the main fluid chamber 56 caused by the elastic deformation of the elastic body 16 is caused by the membrane sheet 90 and the auxiliary membrane sheet 122. Since it can be absorbed reliably, an increase in the dynamic spring constant associated with an increase in the hydraulic pressure in the main liquid chamber 56 can be suppressed, and an elastic body can be used even when such high-frequency vibration is input. The dynamic spring constant of 6 and kept low, can effectively absorb the high frequency vibration by the elastic deformation of the elastic body 16.

  Here, since the air chamber 116 provided outside the auxiliary membrane sheet 122 communicates with the outside and is always maintained at atmospheric pressure, the air in the air chamber 116 is compressed and deformed in the expansion direction. Since the sheet 122 does not become a resistance, it is possible to increase the amount of deformation in the expansion direction even when the dimension of the auxiliary membrane sheet 122 is small compared to the auxiliary membrane sheet 90 according to the second embodiment. Become. It goes without saying that the same effect can be obtained even if the auxiliary membrane sheet 122 faces the external space directly without providing the air chamber 116 outside the auxiliary membrane sheet 122.

  In addition, the membrane sheet 122 and the air chamber 116 in the vibration isolator 110 according to the third embodiment may be added to the vibration isolator 100 according to the second embodiment, or may be provided in the first embodiment. The membrane sheet 90 in the vibration isolator 10 is omitted, the auxiliary membrane sheet 102 in the vibration isolator 100 according to the second embodiment, the air chamber 108, and the auxiliary membrane sheet in the vibration isolator 110 according to the third embodiment. One or both of 122 and the air chamber 116 may be provided in the vibration isolator.

It is side surface 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 structure of the vibration isolator which concerns on the 2nd Embodiment of this invention. It is side surface sectional drawing which shows the structure of the vibration isolator which concerns on the 3rd Embodiment of this invention.

Explanation of symbols

10 Vibration isolator 12 Inner tube bracket (first mounting member)
14 Outer cylinder fitting (second mounting member)
16 Elastic body 48 Partition member 50 Partition bracket (partition member)
56 Main liquid chamber 58 Sub liquid chamber 66 Orifice (restricted passage)
90 Membrane sheet (membrane member)
DESCRIPTION OF SYMBOLS 102 Auxiliary membrane sheet 106 Expansion / contraction part 108 Air chamber 110 Vibration isolator 114 Cover member 116 Air chamber 122 Auxiliary membrane sheet 126 Expansion / contraction part

Claims (7)

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;
A restricting passage communicating the main liquid chamber and the sub liquid chamber with each other;
A membrane member that forms another part of the partition wall of the main liquid chamber and is elastically deformable in a volume expansion / contraction direction that expands / contracts the main liquid chamber according to a change in the liquid pressure of the main liquid chamber; An anti-vibration device having
The membrane member is made of a sheet-like material that is non-stretchable in the tension direction, and is held in a state of being bent in a continuous wave shape or bellows shape in at least a part of the membrane member and elastic in the volume expansion / contraction direction. An anti-vibration device characterized in that an expansion / contraction portion that can be deformed is formed.   2. The vibration isolator according to claim 1, further comprising a partition member that partitions the main liquid chamber and the sub liquid chamber, and the membrane member is provided on the partition member.   2. The vibration isolator according to claim 1, wherein an air chamber is provided on the opposite side of the main liquid chamber through the membrane member.   The vibration isolator according to any one of claims 1 to 3, wherein the sheet material constituting the membrane member is impermeable to liquid.   The vibration isolator according to any one of claims 1 to 4, wherein the sheet material constituting the membrane member is formed of a woven fabric woven with resin fibers.   The vibration isolator according to claim 5, wherein the woven fabric is subjected to a water repellent finish.   The vibration isolator according to any one of claims 1 to 6, wherein the membrane member has a maximum elongation along the tension direction of 10% or less.

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