JP6691456B2 - Fluid-filled cylindrical anti-vibration device - Google Patents

Description

  The present invention relates to a cylindrical vibration damping device applied to an engine mount of an automobile, etc., in which a vibration damping effect is exhibited by utilizing a flow action of a fluid sealed inside. It relates to the device.

  BACKGROUND ART Conventionally, a cylindrical vibration damping device used for an engine mount of an automobile is known. The tubular vibration isolator has a structure in which the inner shaft member is inserted into the outer cylinder member, and the inner shaft member and the outer cylinder member are elastically connected to each other by a main rubber elastic body.

  Further, as one type of the tubular vibration damping device, there is also a fluid-filled tubular vibration damping device that utilizes a vibration damping effect based on a flow action of a fluid sealed inside. In this fluid-filled tubular vibration damping device, as shown in, for example, Japanese Patent No. 3736155 (Patent Document 1), a part of the wall portion between the inner shaft member and the outer tubular member is a main rubber elastic body. A pair of liquid chambers formed of an elastic body are formed, an incompressible fluid is enclosed in the pair of liquid chambers, and an orifice passage that connects the pair of liquid chambers to each other is formed. It has a different structure. Then, with respect to the vibration input in the direction perpendicular to the axis in which the pair of liquid chambers are arranged, fluid flow is generated between the pair of liquid chambers through the orifice passage, and the vibration damping effect based on the fluid flow action is exerted. It has become so.

  By the way, the fluid-filled tubular vibration damping device interposed between the members constituting the vibration transmission system may receive not only vibration in the direction perpendicular to the axis but also vibration in the axial direction. In some cases, anti-vibration performance is required.

  However, in the fluid-filled cylindrical vibration damping device described in Patent Document 1, while vibration damping effect based on the fluid flow action is exerted against vibration in the direction perpendicular to the axis, vibration damping in the axial direction is achieved. However, relative internal pressure fluctuations cannot be induced in the pair of liquid chambers, and the vibration damping effect based on the fluid flow action cannot be obtained.

  In addition, in the fluid filled tubular vibration damping device in which the constituent members of the vibration transmission system are attached to both ends of the inner shaft member, the inner shaft member needs to be inserted into the outer cylinder member, and the axial direction of the inner shaft member It is difficult to form a liquid chamber on the outside. Therefore, the fluid-filled tubular vibration damping device has a structure in which the liquid chamber that causes a relative internal pressure difference due to the relative displacement between the inner shaft member and the outer tubular member due to the input of the axial vibration is communicated with the orifice passage. It was structurally difficult to provide compared to a so-called bowl-shaped fluid filled type vibration damping device. That is, the bowl-shaped fluid filled type vibration damping device is axially displaced by adopting the inner shaft member arranged on one axial side of the outer tubular member without penetrating the outer tubular member in the axial direction. The inner shaft member is made to act on the liquid chamber like a piston, and its basic structure is different from that of the tubular fluid-filled type vibration damping device to which the present invention is directed.

Japanese Patent No. 3736155

  The present invention has been made in the background of the above circumstances, and the problem to be solved is not only the vibration isolation effect against the vibration in the axis-perpendicular direction but also the vibration isolation effect against the vibration in the axial direction. (EN) It is possible to provide a fluid-filled tubular vibration damping device having a novel structure that can be performed.

  Hereinafter, embodiments of the present invention made to solve such problems will be described. The constituent elements used in each of the following aspects can be used in any combination as much as possible.

  According to a first aspect of the present invention, the inner shaft member is inserted into the outer tubular member, and the inner shaft member and the outer tubular member are elastically connected to each other by a main rubber elastic body, and the inner shaft member and the A pair of first liquid chambers, each of which is formed of the main body rubber elastic body, is formed between the outer tubular members, and the pair of first liquid chambers sandwiches the inner shaft member. Located on both sides in the radial direction, an incompressible fluid is enclosed in the pair of first liquid chambers, and an orifice passage is formed that connects the pair of first liquid chambers in the circumferential direction at the outer peripheral portion. In the fluid-filled tubular vibration-damping device, a rubber wall is arranged axially outward of the main body rubber elastic body, and a second annular ring is provided between the main body rubber elastic body and the rubber wall. When a liquid chamber is formed and an incompressible fluid is enclosed in the second liquid chamber, The incompressible fluid sealed in the second liquid chamber is a fluid having a higher viscosity than the incompressible fluids sealed in the pair of first liquid chambers, and the second liquid It is characterized in that at least one end of the chamber is formed with a constriction flow path that is open in the axial direction.

  According to the fluid-filled tubular vibration damping device having the structure according to the first aspect, a relative pressure difference is generated between the pair of first liquid chambers with respect to the vibration in the direction perpendicular to the axis. The fluid flow is generated through the orifice passages that connect the first liquid chambers to each other, so that the vibration damping effect based on the fluid flow action of the fluid is exhibited.

  Furthermore, since the second liquid chamber is filled with a fluid having a higher viscosity than the first liquid chamber, the flow of the fluid occurs in the second liquid chamber with respect to the vibration in the axial direction. An effective anti-vibration effect can be obtained based on the energy damping effect of the viscous resistance. The anti-vibration effect due to the viscous resistance of such a flowing fluid does not require a structure in which a plurality of liquid chambers are communicated with each other by a passage, and a second fluid flow can be generated internally with respect to an axial input. The structure can be simplified because it can be effectively obtained by forming the constriction flow channel that forms the liquid chamber and the energy damping effect due to the viscous resistance in the second liquid chamber. .

  In addition, such a vibration isolation structure that uses the viscous resistance of the flowing fluid is to reduce the flow passage cross-sectional area and flow passage length of the narrowed flow passage compared to the structure that connects multiple liquid chambers with passages. Therefore, even in the fluid-filled tubular vibration damping device in which the inner shaft member is provided so as to penetrate therethrough in the axial direction, it is possible to provide the fluid-free tubular vibration-damping device without causing problems such as fluid leakage and liquid chamber short-circuiting.

  In addition, since the second liquid chamber is formed into an annular shape that is continuous in the circumferential direction, the enclosed high-viscosity fluid easily flows in the circumferential direction against the input vibration in the direction perpendicular to the axis, so that The adverse effect of the fluid flow between the first liquid chambers on the vibration isolation effect is also avoided.

  A second aspect of the present invention is the fluid-filled tubular vibration damping device according to the first aspect, wherein a cylindrical narrowing member extending in the axial direction is provided in the inner shaft member in the second liquid chamber. The constriction flow path is defined by being arranged in an extrapolated state and by partitioning the second liquid chamber by the constriction member.

  According to the second aspect, the second liquid chamber is partitioned by the narrowing member, and the narrowing channel is formed on at least one of the inner peripheral side and the outer peripheral side of the narrowing member, whereby the narrowing member has a simple structure. A flow path can be formed. Further, since the narrowing member has a cylindrical shape, it is easy to form the narrowing channel over the entire circumference, and the vibration damping effect based on the viscous resistance of the fluid flowing in the narrowing channel can be more efficiently achieved. It becomes possible to obtain it.

  A third aspect of the present invention is the fluid-filled tubular vibration damping device according to the second aspect, wherein the narrowing member has a stepped tubular shape, and a small diameter portion of the narrowing member is the inner shaft. The member is fixed to the member in an externally inserted state, and a communication hole penetrating the large diameter portion of the narrowing member is formed, and the narrowing flow path is provided between the large diameter portion of the narrowing member and the inner shaft member. It is formed so as to extend in the axial direction.

  According to the third aspect, the small diameter portion of the narrowing member is fixed to the inner shaft member in an externally inserted state, so that the large diameter portion of the narrowing member is easily held in the second liquid chamber. Further, since the narrowing member is fixed to the inner shaft member, when the inner shaft member and the outer tubular member are relatively displaced in the axial direction by the vibration input in the axial direction, the large diameter portion of the narrowing member and the inner shaft member are The fluid flow in the axial direction is generated in the narrowed flow path formed in the above, and the vibration damping effect based on the viscous resistance of the fluid is exhibited.

  A fourth aspect of the present invention is the fluid filled tubular vibration damping device according to the second or third aspect, wherein the inner peripheral end of the rubber wall is fixed to the outer peripheral surface of the narrowing member. The inner peripheral end of the rubber wall is fluid-tightly supported by the inner shaft member by fixing the narrowing member to the inner shaft member in an externally inserted state.

  According to the fourth aspect, the narrowing member also serves as a structure for attaching the rubber wall to the inner shaft member, so that the number of parts can be reduced and the structure can be simplified.

  A fifth aspect of the present invention is the fluid-filled tubular vibration damping device according to any one of the first to fourth aspects, wherein the incompressible fluid sealed in the pair of first liquid chambers. Has a kinematic viscosity in the range of 10 cSt to 150 cSt, and the incompressible fluid enclosed in the second liquid chamber has a kinematic viscosity in the range of 5000 cSt to 50,000 cSt.

  According to the fifth aspect, the kinematic viscosity of the low-viscosity fluid enclosed in the pair of first liquid chambers is set in the range of 10 cSt to 150 cSt, so that the fluid can flow through the orifice passage at the time of vibration input in the direction perpendicular to the axis. And the vibration damping effect based on the flow action of the fluid is effectively exhibited. On the other hand, by setting the kinematic viscosity of the highly viscous fluid enclosed in the second liquid chamber to be in the range of 5000 cSt to 50000 cSt, while effectively producing the fluid flow in the constriction flow channel against the axial vibration, A large energy damping action due to viscous resistance can be obtained.

  A sixth aspect of the present invention is the fluid-filled tubular vibration damping device according to any one of the first to fifth aspects, wherein the incompressible fluid sealed in the pair of first liquid chambers. Contains at least one of ethylene glycol and propylene glycol, and the incompressible fluid enclosed in the second liquid chamber contains silicone oil.

  According to the sixth aspect, by adopting an incompressible fluid containing at least one of ethylene glycol and propylene glycol as the sealed fluid of the pair of first liquid chambers, even in a low temperature environment or a high temperature environment. The desired vibration damping performance can be stably obtained. On the other hand, by adopting an incompressible fluid containing silicone oil whose viscosity changes little with temperature as the sealed fluid in the second liquid chamber, it is possible to obtain a stable vibration damping effect based on the viscous resistance of the sealed fluid. it can.

  A seventh aspect of the present invention is the fluid filled tubular vibration damping device according to any one of the first to sixth aspects, wherein the deformation amount of the rubber wall toward the outer peripheral side is limited. A restraint member is provided.

  According to the seventh aspect, the amount of deformation of the rubber wall toward the outer peripheral side is limited by the first restraint member, so that the flow of the fluid efficiently occurs in the second liquid chamber when the axial vibration is input. Thus, the vibration damping effect based on the viscous resistance is advantageously exhibited. In particular, since the deformation of the rubber wall to the outer peripheral side is limited by the first restraint member, it is not necessary to limit the deformation of the rubber wall to the outer peripheral side by increasing the thickness of the rubber wall itself, The degree of freedom in designing the rubber wall can be increased.

  An eighth aspect of the present invention is the fluid filled tubular vibration damping device according to any one of the first to seventh aspects, wherein the deformation amount of the rubber wall outward in the axial direction is limited. The second restraint member is provided.

  According to the eighth aspect, the amount of deformation of the rubber wall outward in the axial direction is limited by the second restraint member, so that the flow of the fluid in the second liquid chamber is efficient when the axial vibration is input. The anti-vibration effect based on the viscous resistance is exerted advantageously. In particular, the deformation of the rubber wall outward in the axial direction is limited by the second restraint member, so that the deformation of the rubber wall outward in the axial direction is limited by increasing the thickness of the rubber wall itself. There is no need, and the degree of freedom in designing the rubber wall can be increased.

  According to the present invention, the fluid flow is generated through the orifice passage that communicates the pair of first liquid chambers with respect to the vibration in the direction orthogonal to the axis, and the protection based on the flow action of the fluid is generated. The vibration effect is exhibited. Further, with respect to the vibration in the axial direction, the fluid flows through the constriction passage formed in the second liquid chamber in which the fluid having a higher viscosity than that of the first liquid chamber is sealed, so that the viscosity of the flowing fluid is increased. The intended vibration damping effect is exhibited based on the energy damping effect of the resistance. As described above, according to the present invention, in the fluid filled tubular vibration damping device, not only the vibration damping effect against the vibration in the direction perpendicular to the axis but also the vibration damping effect against the vibration in the axial direction can be effectively obtained.

It is sectional drawing which shows the engine mount as 1st embodiment of this invention, Comprising: It is a figure corresponded to the II cross section of FIG. II-II sectional drawing of FIG. The disassembled perspective view of the engine mount shown in FIG. The exploded perspective view which shows the engine mount shown in FIG. 1 from another direction. 1. VV sectional drawing of FIG. Sectional drawing which shows the engine mount as 2nd embodiment of this invention.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  1 and 2 show an engine mount 10 for an automobile as a first embodiment of a fluid-filled tubular vibration damping device having a structure according to the present invention. The engine mount 10 has a structure in which an inner shaft member 12 and an outer cylinder member 14 are elastically connected to each other by a main rubber elastic body 16. In the following description, as a general rule, the up-down direction is the up-down direction in FIG. 1, the front-back direction is the left-right direction in FIG. 1, which is the axial direction of the engine mount 10, and the left-right direction is the left-right direction in FIG. Say left and right respectively.

  More specifically, the inner shaft member 12 is a high-rigidity member formed of metal such as iron or aluminum alloy, synthetic resin, or the like, and has a small-diameter, generally cylindrical shape as a whole. Further, the inner shaft member 12 of the present embodiment is integrally formed with a pair of stopper protrusions 18, 18 that protrude toward the outer periphery at the axially intermediate portion. The stopper protrusion 18 includes a wide base end portion 20 and a narrow width front end portion 22, and a pair of the stopper protrusion 18 protrudes upward and downward in the radial direction. The stopper protrusion 18 may be formed as a separate component made of, for example, metal or synthetic resin, and may be fixed to the inner shaft member 12 afterward.

  Further, an intermediate sleeve 24 is externally inserted into the inner shaft member 12 so as to be separated from the outer circumference. The intermediate sleeve 24 is a high-rigidity member made of the same material as the inner shaft member 12, has a thin-walled large-diameter substantially cylindrical shape, and has a pair of window portions 26, 26 on both upper and lower sides in the radial direction. Are formed. As shown in FIGS. 1 to 4, the window portion 26 is formed so as to penetrate the axially intermediate portion of the intermediate sleeve 24, and extends in the circumferential direction with a length shorter than a half circumference. Further, a groove 28 is formed between the pair of windows 26, 26 in the circumferential direction of the intermediate sleeve 24. The recessed groove 28 extends in the circumferential direction while opening to the outer peripheral surface in the axially intermediate portion of the intermediate sleeve 24, and both circumferential ends are open to each of the pair of windows 26, 26. The intermediate sleeve 24 has a shorter axial length than the inner shaft member 12.

  The inner shaft member 12 and the intermediate sleeve 24 are arranged substantially concentrically and are elastically connected to each other by the main rubber elastic body 16. The main rubber elastic body 16 has a thick and substantially cylindrical shape, and the inner peripheral surface thereof is vulcanized and adhered to the outer peripheral surface of the inner shaft member 12, and the outer peripheral surface thereof corresponds to the inner peripheral surface of the intermediate sleeve 24. It is vulcanized and bonded, and is formed as an integrally vulcanized molded product including the inner shaft member 12 and the intermediate sleeve 24. The inner shaft member 12 is provided so as to penetrate through the main rubber elastic body 16 in the axial direction, and both axial end portions of the inner shaft member 12 are positioned in the axial direction more than the axial end portions of the main rubber elastic body 16. It protrudes outward and is exposed from the main rubber elastic body 16. In addition, the front and rear surfaces in the axial direction of the main rubber elastic body 16 are concave curved surfaces, and a large free surface is secured.

  Further, the main rubber elastic body 16 is formed with a pair of pockets 30, 30 which are open on both upper and lower sides in the radial direction. The pocket portion 30 is a recess opening on the outer peripheral surface of the main rubber elastic body 16, has an opening shape substantially corresponding to the window portion 26 of the intermediate sleeve 24, and has a stopper protrusion on the inner peripheral bottom surface. 18 is protruding. The pair of pocket portions 30, 30 of the main rubber elastic body 16 are opened toward the outer periphery through the pair of window portions 26, 26 of the intermediate sleeve 24. In this embodiment, the inner surface of the opening of the window portion 26 of the intermediate sleeve 24 and the surface of the stopper protrusion 18 are covered with the main rubber elastic body 16, and in particular, the protruding tip surface of the stopper protrusion 18 is the main rubber elastic body. It is covered with a cushioning rubber 32 formed integrally with 16.

  Furthermore, the outer peripheral surface of the inner shaft member 12 is covered with a rubber layer 34 integrally formed with the main rubber elastic body 16. The rubber layer 34 has a thin, substantially cylindrical shape, and extends from the inner peripheral end of the main rubber elastic body 16 toward the front and rear sides in the axial direction.

  The outer sleeve member 14 is attached to the intermediate sleeve 24. The outer tubular member 14 is a high-rigidity member formed of the same material as the inner shaft member 12 and the intermediate sleeve 24, has a thin-walled large-diameter substantially cylindrical shape, and has a seal rubber on the inner peripheral surface. Layer 36 has been deposited. The outer tubular member 14 has an axial length shorter than that of the inner shaft member 12, and is formed to have substantially the same axial length as the intermediate sleeve 24. The outer tubular member 14 is fluid-tightly fixed to the intermediate sleeve 24 by being externally inserted into the intermediate sleeve 24 and subjected to a diameter reduction process such as an eight-sided drawing. As a result, the inner shaft member 12 is disposed so as to be inserted into the outer tubular member 14, and the inner shaft member 12 projects axially both sides than the outer tubular member 14.

  By fitting the outer tubular member 14 onto the intermediate sleeve 24 in this manner, the pair of window portions 26, 26 of the intermediate sleeve 24 are covered by the outer tubular member 14, and the pair of pocket portions 30, 30 are covered. The opening is fluid-tightly closed by the outer tubular member 14 to define a pair of spaces. By enclosing the incompressible fluid in the pair of spaces, between the inner shaft member 12 and the outer tubular member 14, a part of the wall portion is formed of the main rubber elastic body 16. One liquid chamber 38, 38 is formed. The pair of first liquid chambers 38, 38 are arranged on both sides in the radial direction with the inner shaft member 12 interposed therebetween. The incompressible fluid is sealed in the pair of first liquid chambers 38, 38 by injecting the incompressible fluid into the first liquid chambers 38, 38 after forming the first liquid chambers 38, 38. Although it can be realized by means, it can also be realized by, for example, assembling the integrally vulcanized molded product of the main rubber elastic body 16 and the outer tubular member 14 in a water tank filled with an incompressible fluid.

  The incompressible fluid sealed in the first liquid chambers 38, 38 is not particularly limited, but a fluid having a kinematic viscosity of 10 cSt to 150 cSt is desirable, and for example, water, ethylene glycol, propylene glycol, alkylene. Glycol, silicone oil, a mixed solution thereof, or the like can be preferably used. A mixed liquid containing at least one of ethylene glycol and propylene glycol is particularly desirable as the sealed fluid in the first liquid chambers 38, 38. In the present embodiment, a mixed liquid of ethylene glycol and propylene glycol is used.

  An orifice member 40 is attached to the concave grooves 28, 28 of the intermediate sleeve 24. The orifice member 40 is made of metal, synthetic resin, or the like, and as shown in FIGS. 1 to 4, has a predetermined width in the axial direction and extends in the circumferential direction by less than one full turn, and also has an outer peripheral surface. A circumferential groove 42 that opens and extends in the circumferential direction is formed. The circumferential groove 42 is folded back at any one end of the orifice member 40 in the circumferential direction, so that the circumferential groove 42 as a whole extends in the circumferential direction by a length of more than one round. Further, narrow mounting portions 43 are formed in the front and rear at two locations (left and right side portions) in the circumferential direction of the orifice member 40, and the mounting portions 43, 43 are formed in the concave grooves 28, 28 of the intermediate sleeve 24. By being fitted, the orifice member 40 is supported while being positioned with respect to the intermediate sleeve 24.

  The outer peripheral surface of the orifice member 40 is superposed on the outer cylindrical member 14 via the seal rubber layer 36 by the outer cylindrical member 14 being fitted onto the intermediate sleeve 24. The opening is fluid-tightly covered by the outer tubular member 14. As a result, a tunnel-shaped channel extending in the circumferential direction is formed between the orifice member 40 and the outer tubular member 14.

  Further, the tunnel-shaped flow path formed by the circumferential groove 42 has one end communicated with one first liquid chamber 38 through the first communication hole 44 penetrating the orifice member 40, and the other end. Is connected to the other first liquid chamber 38 through a second communication hole 46 that penetrates the orifice member 40. As a result, an orifice passage 48 that connects the pair of first liquid chambers 38, 38 to each other at the outer peripheral portion is formed. In the orifice passage 48, the tuning frequency grasped as the resonance frequency of the flowing fluid is such that the ratio of the passage cross-sectional area (A) to the passage length (L) ( It is adjusted by setting A / L) appropriately. The tuning frequency of the orifice passage 48 is not particularly limited, but in the present embodiment, it is set to a low frequency of about 10 Hz, which corresponds to, for example, an engine shake.

  An elastic rubber wall 50 as a rubber wall is arranged axially rearward of the main rubber elastic body 16. The elastic rubber wall 50 is a rubber elastic body having a substantially annular shape as a whole, and more specifically, as shown in FIG. 1, an inner peripheral fixing portion 52 having an inner peripheral end portion having a substantially annular plate shape. In addition, a curved portion 54, which is inclined forward as it goes to the outer periphery, is integrally formed on the outer peripheral side of the inner peripheral fixed portion 52, and the outer peripheral end portion of the curved portion 54 is substantially axially front and rear. A tubular portion 56 extending continuously is integrally formed with the front end portion of the tubular portion 56, and a substantially annular plate-shaped outer peripheral fixing portion 58 extending to the outer periphery is continuously formed integrally with the front end portion of the tubular portion 56.

  Further, the narrowing member 60 is fixed to the inner peripheral fixing portion 52 of the elastic rubber wall 50. The narrowing member 60 has a thin-walled, small-diameter, generally stepped cylindrical shape in which a step 62 is provided at an intermediate portion in the axial direction, and a front side of the step 62 is a narrowing cylindrical portion 64 having a large diameter, and a rear side thereof is formed. The inner peripheral fitting portion 66 has a small diameter. The inner peripheral fixing portion 52 of the elastic rubber wall 50 is vulcanized and adhered to the inner peripheral fitting portion 66 of the narrowing member 60 and the outer surface of the step 62.

  Furthermore, an outer peripheral mounting member 68 is fixed to the outer peripheral fixing portion 58 of the elastic rubber wall 50. The outer peripheral mounting member 68 has a large-diameter, substantially annular shape as a whole, and has a substantially cylindrical outer peripheral fitting portion 70 which is externally fitted to the outer tubular member 14, and an inner peripheral surface from a rear end portion of the outer peripheral fitting portion 70. And a fixed flange portion 72 in the form of an inner flange that protrudes toward. The outer peripheral fixing portion 58 of the elastic rubber wall 50 is vulcanized and adhered to the fixing flange portion 72 of the outer peripheral mounting member 68. The elastic rubber wall 50 of the present embodiment is formed as an integrally vulcanized molded product including the narrowing member 60 and the outer peripheral mounting member 68.

  The inner peripheral fitting portion 66 of the narrowing member 60 is externally fitted and fixed to the inner shaft member 12, and the inner peripheral end portion of the elastic rubber wall 50 is mounted on the inner shaft member 12 and the outer peripheral mounting member. An outer peripheral fitting portion 70 of 68 is externally fitted and fixed to the outer tubular member 14, and an outer peripheral end portion of the elastic rubber wall 50 is attached to the outer tubular member 14.

  Since the rubber layer 34 is sandwiched between the inner shaft member 12 and the inner peripheral fitting portion 66 of the narrowing member 60, the inner shaft member 12 and the narrowing member 60 are fluid-tightly sealed. There is. In the present embodiment, the rubber layer 34 is adhered and formed on the surface of the inner shaft member 12, but the rubber layer may be formed, for example, on the inner peripheral surface of the inner peripheral fitting portion 66 of the narrowing member 60. Further, since the outer peripheral fixing portion 58 of the elastic rubber wall 50 is sandwiched between the axial end surfaces of the outer cylindrical member 14 and the intermediate sleeve 24 and the fixing flange portion 72 of the outer peripheral mounting member 68, the outer cylindrical member 14 and A fluid-tight seal is provided between the intermediate sleeve 24 and the outer peripheral mounting member 68.

  In this manner, the elastic rubber wall 50 is attached to the inner shaft member 12 and the outer tubular member 14, and is disposed axially outward of the main rubber elastic body 16, so that the main rubber elastic body 16 and An annular second liquid chamber 74 is defined between the elastic rubber walls 50. In the second liquid chamber 74, a part of the wall portion is composed of the main rubber elastic body 16 and the other part of the wall portion is composed of the elastic rubber wall 50, and the second liquid chamber 74 is internally incompressible. The fluid is enclosed. The elastic rubber wall 50 of the present embodiment is thick enough to cause a fluid flow in the second liquid chamber 74 by the piston action due to its own elasticity when the axial vibration is input. Further, the second liquid chamber 74 of the present embodiment extends annularly around the inner shaft member 12 over the entire circumference with a substantially constant cross-sectional shape.

  Here, the second liquid chamber 74 is filled with an incompressible fluid different from the incompressible fluid filled in the first liquid chambers 38, 38, and particularly the first liquid chambers 38, 38. A high-viscosity fluid having a higher kinematic viscosity than the non-compressible fluid sealed in is sealed. The high-viscosity fluid sealed in the second liquid chamber 74 is not particularly limited, but a fluid having a kinematic viscosity in the range of 5000 cSt to 50,000 cSt is desirable, such as a fluid containing silicone oil or polyethylene glycol. Is preferably used, and is silicone oil in the present embodiment. The kinematic viscosity of the fluid sealed in the second liquid chamber 74 can be appropriately adjusted by mixing powder with the liquid or mixing a plurality of types of liquid. Note that, for example, two types of mixed liquids obtained by mixing the same type of liquid at different ratios are used as one of the sealed fluids of the first liquid chambers 38 and 38 and the sealed fluid of the second liquid chamber 74. You can also

  Further, the narrowed tube portion 64 of the narrowed member 60 is inserted into the second liquid chamber 74. That is, the narrowed cylindrical portion 64 of the narrowed member 60 is arranged at a predetermined distance on the outer peripheral side with respect to the rubber layer 34 covering the surface of the inner shaft member 12, as shown in FIGS. The second liquid chamber 74 is divided into an inner peripheral side and an outer peripheral side by the narrowed cylindrical portion 64. A narrowed region that extends in the axial direction and opens forward is formed between the inner circumferential side of the narrowed cylindrical portion 64, in other words, between the narrowed cylindrical portion 64 and the rubber layer 34. Since the rear end portion is communicated with the communication hole 76 formed through the narrowed tube portion 64, a tubular narrowed flow path 78 that extends in the axial direction between the narrowed tube portion 64 and the rubber layer 34 is formed. There is. The constriction channel 78 has a channel shape (for example, the constriction cylinder portion 64 and the rubber layer 34) so that energy attenuation due to viscous resistance is effectively generated when the high-viscosity fluid enclosed in the second liquid chamber 74 flows. The distance between the facing surfaces, the flow path length, etc.) are set. The communication hole 76 can also be formed in the step 62 of the narrowing member 60.

  As shown in FIG. 5, the cross-sectional area of the narrowed flow passage 78 including the openings on both sides in the axial direction is preferably smaller than the cross-sectional area of the region other than the narrowed flow passage 78 in the second liquid chamber 74. Specifically, for example, the flow passage cross-sectional area of the narrowed flow passage 78 is preferably 40% or less with respect to the cross-sectional area of the same cross section of the entire second liquid chamber 74, and more preferably. Is 30% or less. The cross-sectional area of the narrowed flow passage 78 does not need to be constant in the flow length direction, but is set within the above range in the entire length of the narrowed flow passage 78 with respect to the cross-sectional area of the second liquid chamber 74. Is more desirable.

  In the engine mount 10 having such a structure, for example, the inner shaft member 12 is attached to a power unit (not shown) and the outer cylinder member 14 is attached to a vehicle body (not shown), so that the power unit is mounted via the engine mount 10. Anti-vibration support is provided by the vehicle body. Further, in a state where the engine mount 10 is mounted on a vehicle, vibration is input between the inner shaft member 12 and the outer tubular member 14, and the vibration input from the power unit, which is a vibration source, is vibration-proof. It is designed to prevent transmission to the target vehicle body.

  That is, when vibration in the direction perpendicular to the axis (vertical direction) is input between the inner shaft member 12 and the outer tubular member 14, relative pressure fluctuations in the pair of first liquid chambers 38, 38 arranged vertically. Is triggered. As a result, a fluid flow between the two chambers 38, 38 is generated through the orifice passage 48 that connects the first liquid chambers 38, 38 to each other, and a vibration damping effect based on a fluid action such as a resonance action of the fluid is produced. It is designed to be demonstrated. Particularly, in the present embodiment, the vibration damping effect based on the fluid flow action is effectively exerted against low frequency vibration such as engine shake input in the direction perpendicular to the axis of the engine mount 10.

  Further, since the low-viscosity fluid having a kinematic viscosity of about 10 cSt to 150 cSt is enclosed in the first liquid chambers 38, 38, the fluid flow through the orifice passage 48 is efficiently generated, and the fluid The anti-vibration effect based on the flow action is effectively exhibited. In particular, since the sealed fluid in the first liquid chambers 38, 38 contains at least one of ethylene glycol and propylene glycol, changes in vibration damping performance due to temperature are reduced or avoided, and the desired vibration damping is achieved. The effect can be stably obtained.

  Further, when vibration in the axial direction (front-back direction) is input between the inner shaft member 12 and the outer tubular member 14, elastic deformation of the main rubber elastic body 16 and the elastic rubber wall 50 causes the inside of the second liquid chamber 74. The fluid flow is generated, and the fluid flow is also generated in the narrowed channel 78 formed in the second liquid chamber 74. Here, when the fluid enclosed in the second liquid chamber 74 is a high-viscosity fluid, when fluid flow is generated in the narrowed flow passage 78, the energy damping action due to the viscous resistance of the enclosed fluid is exhibited. As a result, the energy of the input vibration is reduced, and the transmission of the vibration to the vehicle body is reduced or avoided.

  As described above, by positively causing the fluid flow through the orifice passage 48 between the two first liquid chambers 38 and 38 in the resonance state with respect to the input vibration in the vertical direction, the intended vibration damping effect is obtained. On the other hand, against the input vibration (axial vibration) in the front-back direction, the vibration isolation effect by viscous resistance is exerted by utilizing the flow of the highly viscous fluid in one second liquid chamber 74. It is like this.

  Moreover, since the enclosed fluid in the second liquid chamber 74 is a highly viscous fluid and the vibration damping effect is exerted based on the viscous resistance due to the fluid flow in one second liquid chamber 74, the annular first With a simple structure in which the second liquid chamber 74 is formed around the inner shaft member 12, it is possible to obtain a vibration damping effect against axial vibration. Furthermore, by providing the small constriction flow passage 78 without forming an orifice passage that requires a relatively large passage cross-sectional area and passage length, it is possible to effectively obtain a vibration damping effect in the axial direction. In addition, since the narrowed channel 78 is formed so as to be opened in the axial direction, a fluid flow occurs in the narrowed channel 78 at the time of inputting the vibration in the axial direction, and the vibration damping effect against the axial vibration becomes effective. To be demonstrated.

  Furthermore, the high-viscosity fluid having a kinematic viscosity of about 5000 cSt to 50,000 cSt is enclosed in the second liquid chamber 74, so that the fluid flow in the second liquid chamber 74 is sufficient with respect to the axial input. In addition to being generated, the energy damping action based on the viscous resistance of the fluid flowing in the narrowed channel 78 is effectively exhibited, and excellent vibration damping performance can be obtained. In particular, since the non-compressible fluid sealed in the second liquid chamber 74 is made of silicone oil or a mixed solution containing it, the change in viscosity due to temperature is reduced or avoided, and the vibration against axial vibration is prevented. The vibration effect can be stably obtained.

  Further, the narrowing member 60 forming the narrowing flow path 78 has a cylindrical shape, and the inner peripheral fitting portion 66, which is a small diameter portion, is externally fitted and fixed to the inner shaft member 12, thereby forming a large diameter portion. The narrowed cylindrical portion 64 is externally inserted on the outer peripheral side of the inner shaft member 12 at a predetermined distance. As a result, the narrowing member 60 including the narrowing cylindrical portion 64 is provided integrally with the inner shaft member 12, and when the axial vibration is input between the inner shaft member 12 and the outer cylindrical member 14, the inner shaft member 12 is provided. Fluid flow can be effectively generated in the constriction flow path 78 that extends in the axial direction between the constriction member 12 and the constriction member 60.

  Moreover, since the tubular constriction flow path 78 extending in the axial direction is formed over the entire circumference between the inner shaft member 12 and the constriction cylinder portion 64, the rubber layer 34 attached to the inner shaft member 12 is formed. It is possible to obtain a large viscous resistance of the enclosed fluid passing between the outer peripheral surface and the inner peripheral surface of the narrowed cylindrical portion 64, and to obtain the desired vibration damping effect.

  In addition, in the present embodiment, the narrowing member 60 also serves as a mounting structure for the elastic rubber wall 50 to the inner shaft member 12, so that the number of parts is reduced and the structure is simplified.

  FIG. 6 shows an engine mount 80 as a second embodiment of the present invention. In the following description, members and parts that are substantially the same as those in the first embodiment will be denoted by the same reference numerals in the drawings, and description thereof will be omitted.

  That is, the engine mount 80 of this embodiment includes the rubber wall 82. The rubber wall 82 is provided with a flexible film portion 84 that is thin and easily deformable in the thickness direction, and has a thick wall at the inner peripheral end and the outer peripheral end of the flexible film 84. The inner peripheral fixing portion 86 and the outer peripheral fixing portion 88 are integrally formed. The inner peripheral fixing portion 86 is vulcanized and bonded to the inner peripheral fitting portion 66 of the narrowing member 60, and the outer peripheral fixing portion 88 is vulcanized and bonded to the fixing flange portion 72 of the outer peripheral mounting member 68. The outer peripheral attachment member 68 of the present embodiment includes an outer peripheral restraint portion 90 that projects rearward from the inner peripheral end portion of the fixed flange portion 72, and the first restraint member of the present embodiment uses the outer peripheral restraint portion 90. It is configured.

  The narrowing member 60 is fluid-tightly attached to the inner shaft member 12, and the outer peripheral mounting member 68 is fluid-tightly attached to the outer tubular member 14, so that the rubber wall 82 is axially rearward of the main rubber elastic body 16. The second liquid chamber 74 is formed between the main rubber elastic body 16 and the rubber wall 82.

  Further, in the present embodiment, a stopper rubber 92 as a second restraint member is arranged axially rearward of the flexible film portion 84. The stopper rubber 92 is a rubber elastic body having a shallow dish shape as a whole, a through hole formed in a radial center portion thereof, and a substantially annular shape, and is thicker than the flexible film portion 84. Therefore, the bending rigidity is increased. The stopper rubber 92 has a flat plate shape whose inner peripheral portion extends in the direction perpendicular to the axis, and has a curved plate shape whose outer peripheral portion inclines forward (leftward in FIG. 6) in the axial direction as it goes to the outer periphery. The flexible film portion 84 is arranged in contact with the outer surface of the flexible film portion 84 so as to cover the outer surface of the flexible film portion 84. Since the stopper rubber 92 is arranged so as to overlap the flexible film portion 84 in the projection in the axial direction, the deformation of the flexible film portion 84 rearward in the axial direction is limited by the stopper rubber 92. In the present embodiment, the stopper rubber 92 is provided so as to come into contact with substantially the entire flexible film portion 84 in advance, and the stopper rubber 92 is fixed to the inner peripheral fitting portion 66 of the narrowing member 60 in an externally inserted state. Has been done.

  However, such a shape of the stopper rubber 92 is merely an example, and can be changed appropriately. Specifically, for example, the stopper rubber 92 does not need to be provided in a state where the entire stopper rubber 92 is in contact with the flexible film portion 84 in advance, and at least a part of the stopper rubber 92 is flexible film portion. The flexible film portion 84 may be provided so as to be separated from the stopper 84 so as to come into contact with the stopper rubber 92 by deformation. The stopper rubber 92 preferably has a shape along the outer surface of the flexible film portion 84, but may have, for example, an annular flat plate shape.

  According to the engine mount 80 having the structure according to the present embodiment, the amount of deformation of the rubber wall 82 toward the outer peripheral side is limited by the outer peripheral restraint 90 of the outer peripheral mounting member 68, and the shaft of the rubber wall 82 is reduced. Since the amount of deformation rearward in the direction is limited by the stopper rubber 92, when the vibration is input in the axial direction, the fluid flow in the second liquid chamber 74 is caused by the elastic deformation of the main rubber elastic body 16, and the viscosity is increased. Anti-vibration effect due to resistance is effectively exhibited. In particular, even when the rubber wall 82 has a structure including the thin flexible film portion 84, the fluid flow in the second liquid chamber 74 is induced, and the vibration damping effect by viscous resistance is effectively exhibited. It

  Like the engine mount 80 according to the present embodiment, a flexible rubber wall having a small expansion spring constant is adopted, and a first restraint member that limits the amount of deformation of the rubber wall toward the outer peripheral side is used. Experiments show that the structure provided with the second restraint member that limits the amount of outward deformation of the rubber wall in the axial direction exhibits the vibration damping effect based on the viscous resistance of the fluid against axial vibration. Has been confirmed by.

  In the present embodiment, the outer peripheral restraint portion 90 that limits the amount of displacement of the rubber wall 82 toward the outer peripheral side is integrally formed with the outer peripheral mounting member 68, but the amount of displacement of the rubber wall 82 toward the outer peripheral side is limited. The first restraint member may be a member separate from the outer peripheral mounting member 68 and the rubber wall 82. Specifically, for example, by disposing the cylindrical first restraint member as a separate body so as to surround the periphery of the rubber wall 82, the deformation amount of the rubber wall 82 toward the outer peripheral side is the first restraint member. It can also be restricted by abutting against.

  Further, the second restraining member is composed of a stopper rubber 92 which is a separate body from the narrowing member 60 and the like. For example, the axial rear end portion of the narrowing member 60 is bent to the outer peripheral side, and the rubber wall 82. The amount of deformation in the axial rearward direction may be limited by contacting the bent portion. In short, the second restraint member that limits the amount of axial displacement of the rubber wall 82 may be formed integrally with the narrowing member 60 or the like. It is also possible to integrally form the stopper rubber 92 with the rubber wall 82.

  Further, although it is desirable to provide both the first restraint member and the second restraint member, only one of them may be provided.

  Although the embodiment of the present invention has been described in detail above, the present invention is not limited by the specific description thereof. For example, although the tubular narrowing member is exemplified in the above-described embodiment, the narrowing member is not necessarily limited to the tubular shape, and is a curved plate shape extending in the circumferential direction with a length less than one round, and the inner shaft is formed. It may be fixed to the outer peripheral surface of the member. Further, the constriction member does not need to be tubular or plate-shaped as a whole. For example, the constriction channel forming portion may be a curved plate and the mounting portion to the inner shaft member may be tubular or annular. A structured structure or the like can also be adopted.

  Further, the constriction flow channel is not necessarily limited to one that is continuously provided over the entire circumference, and may be provided, for example, at a part of the circumferential direction or at a plurality of positions in the circumferential direction.

  Further, in the above-described embodiment, the narrowed flow path is formed between the narrowed member and the inner shaft member, but it is also possible to form the hole-shaped narrowed flow path through the thickened narrowed member, for example.

  Further, the narrowing member may be supported by the outer tubular member or the intermediate sleeve, or may be disposed and supported in the second liquid chamber by being fixed to the main rubber elastic body or the rubber wall. Further, although the narrowing member of the above-described embodiment has a structure that projects from the outside in the axial direction and opens to the inside in the axial direction, it may have a structure that projects from the inside in the axial direction and opens to the outside in the axial direction. Incidentally, the peripheral wall portion of the constriction channel is preferably a hard wall structure which is not substantially deformed as shown in the above embodiment, and thereby the channel cross-sectional shape of the constriction channel is stable, The shear-shearing damping effect due to the flow of the highly viscous fluid can be stably and efficiently exhibited.

  Further, in the elastic rubber wall 50 of the first embodiment, the inner peripheral fixing portion 52, the curved portion 54, and the tubular portion 56 are formed with a substantially constant thickness, and the second liquid due to the deformation of the elastic rubber wall 50 is formed. Although the expansion of the chamber 74 is limited over the entire elastic rubber wall 50, the thickness of the elastic rubber wall 50 does not necessarily have to be constant, and for example, a partially thin or thick portion may be provided. it can.

10, 80: Engine mount (fluid-filled tubular vibration isolator), 12: Inner shaft member, 14: Outer tubular member, 16: Main rubber elastic body, 38: First liquid chamber, 48: Orifice passage, 50 : Elastic rubber wall (rubber wall), 60: narrowing member, 64: narrowing tubular portion (large diameter portion of narrowing member), 66: inner peripheral fitting portion (small diameter portion of narrowing member), 74: second liquid chamber , 76: communication hole, 78: narrowed flow path, 82: rubber wall, 90: outer peripheral restraint portion (first restraint member), 92: stopper rubber (second restraint member)

Claims (8)

The inner shaft member is inserted through the outer tubular member, and the inner shaft member and the outer tubular member are elastically connected to each other by the main rubber elastic body, and
Between the inner shaft member and the outer tubular member, a pair of first liquid chambers, a part of the wall of which is made of the main rubber elastic body, is formed. They are arranged on both sides in the radial direction with the inner shaft member sandwiched between them, and an incompressible fluid is enclosed in the pair of first liquid chambers, and the pair of first liquid chambers are circumferentially formed in the outer peripheral portion. In a fluid-filled tubular vibration-damping device in which a communicating orifice passage is formed,
A rubber wall is disposed axially outward of the main rubber elastic body, and an annular second liquid chamber is formed between the main rubber elastic body and the rubber wall. And a non-compressible fluid sealed in the second liquid chamber, the non-compressible fluid having a higher viscosity than the non-compressible fluid sealed in the pair of first liquid chambers. Has been done,
Further, in the second liquid chamber, a confined flow path having at least one end opening in the axial direction is formed.   A cylindrical narrowing member extending in the axial direction is disposed in the second liquid chamber in a state of being externally fitted to the inner shaft member, and the second liquid chamber is partitioned by the narrowing member. The fluid filled tubular vibration damping device according to claim 1, wherein the narrowed flow path is defined.   The narrowing member has a stepped cylindrical shape, a small diameter portion of the narrowing member is fixed to the inner shaft member in an externally inserted state, and a communication hole penetrating the large diameter portion of the narrowing member is formed. The fluid-filled tubular vibration damping device according to claim 2, wherein the narrowed flow path is formed so as to extend in an axial direction between a large-diameter portion of the narrowed member and the inner shaft member.   An inner peripheral end portion of the rubber wall is fixed to an outer peripheral surface of the narrowing member, and the inner peripheral end portion of the rubber wall is fixed to the inner shaft member by being fixed to the inner shaft member. The fluid filled cylindrical vibration damping device according to claim 2 or 3, which is fluid-tightly supported by the shaft member.   The incompressible fluid enclosed in the pair of first liquid chambers has a kinematic viscosity in the range of 10 cSt to 150 cSt, and the incompressible fluid enclosed in the second liquid chamber has a kinematic viscosity of 5000 cSt. The fluid filled tubular vibration damping device according to any one of claims 1 to 4, wherein the range is -50000 cSt.   The incompressible fluid enclosed in the pair of first liquid chambers contains at least one of ethylene glycol and propylene glycol, and the incompressible fluid enclosed in the second liquid chamber contains silicone oil. The fluid filled tubular vibration damping device according to any one of claims 1 to 5.   The fluid-filled tubular vibration damping device according to claim 1, further comprising a first restraint member that limits an amount of deformation of the rubber wall toward the outer peripheral side.   The fluid-filled tubular vibration damping device according to claim 1, further comprising a second restraint member that limits an amount of deformation of the rubber wall outward in the axial direction.

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