JP5386289B2 - Fluid filled vibration isolator - Google Patents

Description

  The present invention relates to an anti-vibration device used for an engine mount and a sub-frame mount of an automobile, and more particularly to a fluid-filled anti-vibration device that uses an anti-vibration effect based on a fluid action of a fluid enclosed inside.

  Conventionally, as a type of vibration isolator that is interposed between members constituting a vibration transmission system and that mutually vibrate and connect these members, a fluid-filled vibration-proof vibration that utilizes the fluid action of the fluid enclosed inside The device is known. The fluid-filled vibration isolator has a structure in which a pressure receiving chamber filled with an incompressible fluid and an equilibrium chamber are communicated with each other by an orifice passage. For example, it is shown in patent document 1 (Unexamined-Japanese-Patent No. 2006-183675).

  By the way, in the fluid filled type vibration isolator, the ratio of the passage length of the orifice passage and the cross-sectional area of the passage and the wall spring rigidity of the pressure receiving chamber and the equilibrium chamber are adjusted to tune the frequency at which the fluid resonance action is exerted, By adjusting the support spring rigidity of the main rubber elastic body, it meets the required anti-vibration characteristics.

  However, considering the durability and the size of the fluid-filled vibration isolator, there are limits to the adjustable range of the frequency tuning of the orifice passage and the support spring characteristics of the main rubber elastic body. In some cases, it was difficult to achieve.

JP 2006-183675 A

  The present invention has been made in the background of the above-mentioned circumstances, and the problem to be solved is that the required vibration-proof characteristics can be effectively achieved by realizing greater tuning freedom and broadening of the vibration-proof characteristics. An object of the present invention is to provide a fluid-filled vibration isolator having a novel structure that is exhibited.

That is, according to the first aspect of the present invention, the first mounting member and the second mounting member are separated from each other on one opening side of the second mounting member having a cylindrical shape. One opening of the second mounting member is closed by the main rubber elastic body connecting the members, and the other opening of the second mounting member is closed by a flexible membrane, On both sides of the partition member supported by the second mounting member, a part of the wall part is made of a pressure-receiving chamber made of the main rubber elastic body, and a part of the wall part is made of the flexible film. A fluid-filled vibration isolator in which an incompressible fluid is sealed in the pressure receiving chamber and the equilibrium chamber, and an orifice passage is formed to communicate the pressure receiving chamber and the equilibrium chamber with each other. in the apparatus, provided with a cylindrical peripheral wall portion which is curved cross-section which is convex to the outer peripheral side and the upper base in the axial direction A cup-shaped bag-shaped rubber is disposed so as to protrude from the central portion of the partition member toward the first mounting member by fixing the peripheral edge of the opening to the partition member. by the mounting member approach displacement of the second mounting member such that the upper base portion peripheral wall tubular of by being pressed and elastically deformed by said first attachment member is bulging deformation in the radial direction On the other hand, an opening on the pressure receiving chamber side of the orifice passage is provided so as to open radially inward at a position where the bag-like rubber is removed from the outer peripheral side, and the cylindrical peripheral wall of the bag-like rubber And a vibration-proof control unit that determines the communication state between the inner region of the bag-shaped rubber and the equilibrium chamber at the opening portion of the bag-shaped rubber in the partition member. It is provided.

  According to the first aspect of the present invention as described above, a greater degree of tuning freedom in vibration-proof characteristics can be realized by using the spring rigidity of the bag-like rubber as an auxiliary. That is, by adjusting the support spring rigidity of the main rubber elastic body and appropriately adjusting the spring rigidity of the bag-like rubber, the spring characteristics can be more greatly adjusted.

  Further, according to the present invention, an improvement in the vibration isolation effect by the orifice passage is realized. That is, when the upper part of the bag-shaped rubber is displaced so as to approach the partition member due to the contact between the first mounting member and the bag-shaped rubber, the peripheral wall portion of the bag-shaped rubber bulges and deforms in the radial direction, thereby The incompressible fluid is guided to the opening on the pressure receiving chamber side of the orifice passage formed on the outer peripheral side of the rubber-like rubber, and the amount of fluid flow through the orifice passage increases. As a result, the anti-vibration effect by the orifice passage is more efficiently exhibited and the anti-vibration performance is improved.

  Further, the auxiliary spring action utilizing the spring rigidity of the bag-like rubber makes it possible to employ a rubber material having a low rubber hardness as the material of the main rubber elastic body. Therefore, the ratio of the static spring constant (ks) and the dynamic spring constant (kd) of the main rubber elastic body (static ratio: kd / ks) can be set small, and the static support spring rigidity can be reduced. It is possible to reduce the dynamic spring of the main rubber elastic body while ensuring sufficient.

  In addition, the vibration control part that determines the communication mode between the inner region of the bag-like rubber and the equilibrium chamber, and the communication mode, etc. is provided, so that not only the elasticity of the bag-like rubber but also the inner region is used. Thus, various anti-vibration effects as shown in the following second to fourth aspects are exhibited. That is, in the fluid-filled vibration isolator having the structure according to the present invention, by adopting the bag-shaped rubber, the vibration-proof control unit does not change the basic structure including the main rubber elastic body. By adjusting and setting the relative communication / blocking state between the internal region and the equilibrium chamber, different vibration isolation characteristics can be easily changed and set with a large degree of tuning freedom.

  According to a second aspect of the present invention, in the fluid-filled vibration isolator described in the first aspect, the anti-vibration control unit is a closed lid portion that seals the inner region of the bag-like rubber. It is.

  According to the 2nd aspect, the effect according to the characteristic of the fluid enclosed with an internal area | region is exhibited by sealing the internal area | region of bag-like rubber with a closure lid part.

  Specifically, for example, if an incompressible fluid is sealed in the inner region of the bag-like rubber, the volume of the inner region is held substantially constant, so the upper bottom portion of the bag-like rubber is pushed by the first mounting member. When elastically deformed, the peripheral wall portion of the bag-like rubber bulges and deforms in the radial direction. As a result, the piston action in the axial direction at the radially central portion is converted into the radially outward piston action by the bag-shaped rubber, and the incompressible fluid sealed in the pressure receiving chamber is formed in the outer peripheral portion of the partition member. Efficiently guided into the orifice passage.

  On the other hand, for example, if a compressive fluid such as air is enclosed in the inner region of the bag-like rubber, the volume of the inner region becomes variable and the elasticity of the compressible fluid enclosed by the deformation of the bag-like rubber is exhibited. As a result, in addition to the change in the vibration isolation characteristics based on the viscoelasticity of the bag-shaped rubber itself, the vibration isolation characteristics also change due to the viscoelasticity of the compressible fluid enclosed in the internal region. A significant change can be expected. Further, since minute deformation of the bag-like rubber is allowed by the density change of the fluid sealed in the inner region, a hydraulic pressure absorption mechanism that absorbs the hydraulic pressure in the pressure receiving chamber is realized by elastic deformation of the bag-like rubber, It is also possible to obtain a low dynamic spring effect with respect to the input of high frequency small amplitude vibration. Furthermore, when an excessive negative pressure is exerted on the pressure receiving chamber, the negative pressure in the pressure receiving chamber is relieved by the expansion of the fluid sealed in the inner region, and noise or vibration caused by cavitation can be reduced or prevented. Can be illustrated. In addition, it is possible to realize a fluid-filled vibration isolator having the same structure and different vibration-proof characteristics by appropriately selecting the compressive fluid sealed in the internal region.

  According to a third aspect of the present invention, in the fluid-filled vibration isolator described in the first aspect, the vibration isolating control unit includes an opening hole for opening an internal region of the bag-like rubber to the equilibrium chamber. It is what has been.

  In the third aspect, since the inner region of the bag-like rubber communicates with the equilibrium chamber, the bag-like rubber is positively reduced in a resonance state when a small amplitude vibration having a frequency higher than the tuning frequency of the orifice passage is input. By deforming, the hydraulic pressure in the pressure receiving chamber is released to the equilibrium chamber and absorbed. As a result, an effective anti-vibration effect (low dynamic spring effect) against high-frequency small-amplitude vibration is exhibited. Moreover, when a large amplitude vibration is input in the frequency range in which the orifice passage is tuned, the fluid pressure absorption action is limited by the spring rigidity of the bag-like rubber. Anti-vibration effect (high attenuation effect) can be obtained.

  In addition, when an excessive negative pressure is applied to the pressure receiving chamber due to the input of a shocking large load, the bag-like rubber expands based on the relative pressure difference between the pressure receiving chamber and the equilibrium chamber, so that the pressure receiving chamber It is also possible to quickly reduce the negative pressure. As a result, it is possible to reduce or avoid cavitation noise generated by an excessive negative pressure in the pressure receiving chamber.

  According to a fourth aspect of the present invention, in the fluid-filled vibration isolator described in the first aspect, the vibration control unit is a second orifice passage tuned to a higher frequency region than the orifice passage. It is what has been.

  According to the fourth aspect, at the time of vibration input in the tuning frequency range of the orifice passage, the fluid pressure in the pressure receiving chamber is secured by the spring rigidity of the bag-like rubber, thereby ensuring the fluid flow amount through the orifice passage. It is possible to obtain a vibration isolation effect by the passage. In particular, the bag-shaped rubber has a peripheral wall part and an upper bottom, and has an inverted cup shape that protrudes toward the pressure-receiving chamber, so that the effect of preventing hydraulic pressure escape due to the spring rigidity of the bag-shaped rubber is more effectively exhibited. Is done.

  On the other hand, when vibration having a frequency higher than the vibration in the tuning frequency range of the orifice passage is input, the orifice passage is substantially closed and the bag-like rubber is elastically deformed by the pressure fluctuation in the pressure receiving chamber. In the piston action based on the elastic deformation of the bag-like rubber, the resonance phenomenon of the bag-like rubber can be used, and fluid flow through the second orifice passage is generated between the pressure receiving chamber and the equilibrium chamber. Then, based on the flow action of the fluid flowing through the second orifice passage, it is possible to obtain a desired vibration isolation effect such as a low dynamic spring action.

  As described above, the double-orifice structure including the orifice passage and the second orifice passage realizes an effective vibration-proofing effect against vibrations in a wider frequency range. Moreover, by providing a bag-shaped rubber of a specific shape so as to close the opening on the pressure receiving chamber side of the second orifice passage, switching between communication and blocking of the second orifice passage according to the frequency of the input vibration, The anti-vibration effect by the orifice passage and the anti-vibration effect by the second orifice passage can be selectively and effectively exhibited.

  Further, a fifth aspect of the present invention is the fluid-filled vibration isolator described in any one of the first to fourth aspects, wherein the end portion on the upper bottom portion side of the peripheral wall portion of the bag-shaped rubber is provided. Has a tapered shape with a diameter decreasing toward the upper bottom side.

  According to the fifth aspect, when the upper bottom portion of the bag-shaped rubber is pushed by the first mounting member, the radially outward component force acts on the circumferential wall portion of the bag-shaped rubber, and the circumferential wall portion of the bag-shaped rubber Is elastically deformed stably so as to be convex toward the outer peripheral side. As a result, the intended auxiliary spring effect is effectively exhibited, and the piston action toward the outer periphery due to the bulging deformation in the radial direction is also stably exhibited. In addition, after the load input from the first mounting member is released, the initial shape can be more reliably restored.

  Moreover, the sixth aspect of the present invention is the fluid-filled vibration isolator described in any one of the first to fifth aspects, wherein the end of the peripheral wall portion of the bag-shaped rubber on the partition member side In this, a concave groove is formed which is open to the outer peripheral surface and continuously extends over the entire circumference.

  According to the 6th aspect, the surrounding wall part of bag-like rubber is easy to fall to the outer peripheral side in the edge part by the side of the partition member. Therefore, when the upper bottom portion of the bag-like rubber is pushed to the partition member side by the first mounting member, the peripheral wall portion is elastically deformed so as to be convex toward the outer peripheral side, and the auxiliary spring effect and the piston action in the radial direction Etc. are stably exhibited.

  In the fluid-filled vibration isolator having a structure according to the present invention, a bag-shaped rubber protruding in the pressure receiving chamber is provided, and a vibration-proof control unit is provided in the opening of the bag-shaped rubber, so It is possible to appropriately use elasticity, compressibility or incompressibility of the inner region of the bag-like rubber, and fluid flow effect exhibited between the inner region and the equilibrium chamber. Therefore, effective vibration isolation can be achieved simply by adjusting the communication state between the inner region of the bag-shaped rubber and the equilibrium chamber with the vibration isolation control unit without significantly changing the basic structure of the vibration isolation device including the rubber elastic body. Greater freedom of tuning, such as broadening the anti-vibration characteristics by expanding the effective frequency range, enhancing the anti-vibration effect against vibration at specific frequencies, and reducing or avoiding cavitation noise It becomes feasible.

BRIEF DESCRIPTION OF THE DRAWINGS The longitudinal cross-sectional view which shows the engine mount for motor vehicles as 1st embodiment of this invention. FIG. 2 is a cross-sectional view of a main part for explaining deformation due to vibration input of the automobile engine mount shown in FIG. 1, wherein (a) shows a stand-alone state, and (b) shows a vibration input state when the vehicle is mounted. , Respectively. The longitudinal cross-sectional view which shows the engine mount for motor vehicles as 2nd embodiment of this invention. The longitudinal cross-sectional view which shows the engine mount for motor vehicles as 3rd embodiment of this invention.

  Embodiments of the present invention will be described below with reference to the drawings.

  FIG. 1 shows an automotive engine mount 10 as a first embodiment of a fluid filled type vibration damping device having a structure according to the present invention. The engine mount 10 has a structure in which a first mounting member 12 and a second mounting member 14 are connected by a main rubber elastic body 16. The first attachment member 12 is attached to the power unit that is one member constituting the vibration transmission system, and the second attachment member 14 is attached to the vehicle body that is the other member constituting the vibration transmission system. Thus, the power unit is supported by the vehicle body in a vibration-proof manner. In the following description, the vertical direction means, in principle, the vertical direction in FIG. 1, which is the main vibration input direction.

  More specifically, the first mounting member 12 is a high-rigidity member having a small-diameter, generally circular block shape, and has an embedded portion 18 having a reverse truncated cone shape that decreases in diameter toward the bottom. A substantially columnar projecting portion 20 projecting upward from the large-diameter end of the embedded portion 18 is integrally provided. The lower end surface of the embedded portion 18 is a flat contact surface 21 that extends in a direction substantially perpendicular to the axis. Further, on the central axis of the first mounting member 12, a bolt hole 22 in which a thread is threaded on the inner peripheral surface is formed. The first mounting member 12 is attached to a power unit (not shown) directly or via an inner bracket or the like by a mounting bolt (not shown) screwed into the bolt hole 22.

  The second mounting member 14 is a highly rigid member having a thin, large-diameter, generally cylindrical shape, and a constricted portion 24 is formed at the upper end thereof. The constricted portion 24 is formed by an inner flange-shaped stepped portion 26 and an inversely tapered tapered portion 28 that projects while gradually increasing in diameter from the inner peripheral edge thereof, and is recessed toward the inner peripheral side. It has a vertical cross-sectional shape. Further, a cylindrical cylindrical portion 30 extends downward from the outer peripheral edge portion of the step portion 26 in the constricted portion 24.

  The first mounting member 12 and the second mounting member 14 are disposed on the same central axis, and the first mounting member 12 is spaced upward from the upper opening of the second mounting member 14. The The main rubber elastic body 16 is interposed between the first mounting member 12 and the second mounting member 14, and the first mounting member 12 and the second mounting member 14 are elastically connected to each other. Yes.

  The main rubber elastic body 16 has a thick-walled large-diameter substantially truncated cone shape, and the first mounting member 12 is vulcanized and bonded to the small-diameter side end portion with the embedded portion 18 embedded therein. At the same time, the constricted portion 24 of the second mounting member 14 is superimposed on the outer peripheral surface of the end portion on the large diameter side and vulcanized and bonded. Thus, the first mounting member 12 and the second mounting member 14 are connected by the main rubber elastic body 16, and the upper opening of the second mounting member 14 is closed by the main rubber elastic body 16. . The main rubber elastic body 16 is formed as an integrally vulcanized molded product including the first and second mounting members 12 and 14.

  The main rubber elastic body 16 is formed with a large-diameter recess 32 that opens to the end surface on the large-diameter side. The large-diameter recess 32 is formed in a reverse mortar shape that expands downward, and the large-diameter recess 32 is formed so that the large-diameter side end of the main rubber elastic body 16 is annular. . In addition, a thin rubber large-diameter cylindrical sealing rubber layer 34 projecting downward is integrally formed on the outer peripheral edge of the large-diameter end of the main rubber elastic body 16. The seal rubber layer 34 is vulcanized and bonded to the inner peripheral surface of the cylindrical portion 30 of the second mounting member 14, and substantially the entire inner peripheral surface of the cylindrical portion 30 is covered with the seal rubber layer 34.

  A diaphragm 36 as a flexible film is attached to the lower opening of the second attachment member 14. The diaphragm 36 has a thin and large-diameter substantially disk shape or a circular dome shape, and has sufficient slackness in the axial direction. In addition, an annular fixing portion 38 is integrally formed on the outer peripheral edge of the diaphragm 36, and an annular fixing fitting 40 is vulcanized and bonded to the fixing portion 38. In other words, the fixing hole 38 is vulcanized and bonded to the inner peripheral surface of the fixture 40 over the entire circumference, so that the central hole of the fixture 40 is closed by the diaphragm 36. And the diaphragm 36 is attached so that the lower opening part of the 2nd attachment member 14 may be obstruct | occluded, when the fixing metal fitting 40 is supported by the 2nd attachment member 14. FIG. For example, the fixing bracket 40 is subjected to a diameter reduction process such as an eight-way drawing on the cylindrical portion 30 of the second mounting member 14 after the fixing bracket 40 is inserted into the lower opening of the second mounting member 14. By being applied, the second mounting member 14 is fixed.

  By fixing the diaphragm 36 to the second mounting member 14, the upper opening of the second mounting member 14 is closed by the main rubber elastic body 16 and the lower opening is closed by the diaphragm 36. ing. Thus, a fluid sealing region 42 in which an incompressible fluid is sealed is formed between the main rubber elastic body 16 and the diaphragm 36 in the axial direction. The incompressible fluid sealed in the fluid sealing region 42 is not particularly limited, but water, alkylene glycol, polyalkylene glycol, silicone oil, or a mixed solution thereof is preferably employed. Further, in order to efficiently obtain a vibration isolation effect based on the fluid flow action described later, a low viscosity fluid of 0.1 Pa · s or less is desirable.

  A partition member 44 is disposed in the fluid sealing region 42. The partition member 44 is a high-rigidity member having a thick and large-diameter substantially disk shape, and includes a first partition member body 46 and a second partition member body 48.

  The first partition member main body 46 has a large-diameter substantially disk shape, and a circular recess 50 that opens to the upper surface is formed in the central portion in the radial direction, and the center of the bottom wall portion of the circular recess 50 is formed. A central hole 52 penetrating in the axial direction is formed. A first circumferential groove 54 is formed in the outer peripheral edge of the first partition member main body 46 so as to open to the outer circumferential surface and extend in the circumferential direction by a predetermined length.

  The second partition member main body 48 has a substantially disc shape having a diameter substantially equal to that of the first partition member main body 46, and has a small-diameter and shallow central recess 56 that opens on the upper surface with respect to the central portion in the radial direction. Is formed. Further, a cutout that opens in the outer peripheral surface and the upper surface and extends in the circumferential direction is formed in the outer peripheral edge of the second partition member main body 48, and the upper opening of the cutout is the first partition member main body 46. The second circumferential groove 58 is formed by being closed by.

  The partition member 44 is formed by overlapping the first partition member body 46 and the second partition member body 48 in the axial direction. The partition member 44 is inserted into the second mounting member 14 and is sandwiched between axially opposed surfaces of the large-diameter side end portion of the main rubber elastic body 16 and the fixing fitting 40 fixed to the diaphragm 36. .

  In addition, since the partition member 44 is supported by the second mounting member 14, the fluid sealing region 42 is divided into two sides on both sides of the partition member 44. That is, on the upper side in the axial direction across the partition member 44, a pressure receiving chamber 60 is formed in which a part of the wall portion is constituted by the main rubber elastic body 16 and the internal pressure fluctuation is exerted. On the lower side in the axial direction across the partition member 44, there is formed an equilibrium chamber 62 in which a part of the wall portion is constituted by the diaphragm 36 and the volume change is easily allowed.

  Further, the diameter reduction process is performed on the second mounting member 14, so that the cylindrical portion 30 of the second mounting member 14 is in close contact with the outer peripheral surface of the partition member 44 via the seal rubber layer 34. The openings of the first and second circumferential grooves 54, 58 formed in the member 44 are covered with the second mounting member 14 in a fluid-tight manner. Further, the first and second circumferential grooves 54 and 58 are communicated with each other through a connection hole 64 formed in the first partition member main body 46, and a tunnel-like passage extending spirally as a whole is formed. ing. One end portion of the tunnel-shaped passage is communicated with the pressure receiving chamber 60 through the first communication hole 66 that radially penetrates the inner peripheral wall portion, and the other end portion is the bottom wall portion. Is connected to the equilibrium chamber 62 through a second communication hole 68 penetrating in the axial direction. Thus, the partition member 44 is formed with an orifice passage 70 that communicates the pressure receiving chamber 60 and the equilibrium chamber 62 with each other using the first and second circumferential grooves 54 and 58. The orifice passage 70 is tuned to a low frequency of several Hz to about 10 Hz corresponding to the engine shake by appropriately setting the ratio (A / L) of the passage sectional area (A) and the passage length (L). ing.

  Further, the first partition member main body 46 and the second partition member main body 48 are overlapped in the axial direction, whereby the central recess 56 formed in the second partition member main body 48 becomes the first partition member main body. The pressure receiving chamber 60 is opened through a central hole 52 formed in 46.

  The partition member 44 is provided with a bag-like rubber 72 that closes the opening of the central hole 52 on the pressure receiving chamber 60 side. The bag-like rubber 72 as a whole has a substantially circular dome shape or a substantially cup shape in the opposite direction, and has a structure in which a cylindrical peripheral wall portion 74 and a substantially disc-shaped upper bottom portion 76 are integrally formed. Yes.

  The peripheral wall portion 74 has a substantially circular cylindrical shape, and a lower portion thereof is a cylindrical support portion 78 and an upper portion is a connecting portion 80 whose diameter is reduced upward. A concave groove 82 is formed in the support portion 78 on the outer peripheral surface of the intermediate portion in the axial direction. The concave groove 82 is a shallow groove that opens to the outer peripheral surface in the intermediate portion in the axial direction of the support portion 78, and continuously extends in a substantially constant groove cross-sectional shape over the entire circumference. By forming the concave groove 82, the outer peripheral surface of the support portion 78 in the peripheral wall portion 74 is partially recessed at the axial intermediate portion, and the support portion 78 is partially thin at the axial intermediate portion. It has become. In addition, a flange-like fixing piece 84 protruding to the outer peripheral side is integrally formed at a portion of the support portion 78 where the concave groove 82 is removed downward. On the other hand, the connecting portion 80 is integrally formed so as to protrude upward from the upper end of the support portion 78, and has a tapered shape that gradually decreases in diameter toward the upper side with a curved cross section that protrudes toward the outer peripheral side. The whole is formed with a substantially constant thickness.

  The upper bottom portion 76 has a substantially disk shape having a smaller diameter than the inner diameter of the support portion 78 in the peripheral wall portion 74, and the connecting portion 80 extends integrally from the outer peripheral surface. Further, the upper bottom portion 76 is thicker than the peripheral wall portion 74, and the connecting portion 80 of the peripheral wall portion 74 extends from the lower end of the outer peripheral surface of the upper bottom portion 76. Thereby, the reverse cup-shaped bag-like rubber 72 having the peripheral wall portion 74 and the upper bottom portion 76 as a whole is formed. The lower surface of the upper bottom portion 76 is smoothly connected to the inner peripheral surface of the connecting portion 80 without causing a step or unevenness, and the upper surface of the upper bottom portion 76 forms a step with respect to the outer peripheral surface of the connecting portion 80. The contact surface 86 protrudes upward.

  The opening of the bag-like rubber 72 having such a structure is vulcanized and bonded to the peripheral edge of the central hole 52 in the first partition member body 46. That is, the lower end opening of the peripheral wall 74 is inserted into the central hole 52 and the adhesive piece 84 is vulcanized and bonded to the first partition member main body 46 in a state where the fixing piece 84 is overlapped with the opening peripheral edge of the central hole 52. Has been. As a result, the bag-like rubber 72 substantially entirely protrudes into the pressure receiving chamber 60 at the radial center.

  Further, the contact surface 86 of the upper bottom portion 76 of the bag-like rubber 72 is opposed to the contact surface 21 of the first mounting member 12 in the axial direction. In addition, the central portion of the layered rubber elastic body 16 is vulcanized and bonded to the contact surface 21 of the first mounting member 12, and the contact surface 21 is covered with the main rubber elastic body 16. Yes. Further, the diameter of the abutted surface 86 in the bag-like rubber 72 is smaller than the diameter of the upper bottom wall portion of the large-diameter recess 32 having a reverse mortar shape. Further, as shown in FIG. 2 (a), in the single state before mounting on the vehicle, the gap between the upper bottom portion 76 of the bag-like rubber 72 and the first mounting member 12 (main rubber elastic body 16). A gap is formed, and they are opposed to each other with a predetermined distance in the axial direction.

  The opening of the bag-like rubber 72 is covered with a second partition member main body 48, and an internal region 88 is formed between the axially facing surfaces of the bag-like rubber 72 and the second partition member main body 48. Yes. The internal region 88 is formed with the bag-shaped rubber 72 separated from the pressure receiving chamber 60, and is provided with a vibration control unit provided at the radial center portion of the second partition member body 48 with respect to the equilibrium chamber 62. Are formed with a closed cover 89 as a space. In other words, a space in which the opening portion of the bag-like rubber 72 is closed by the closing lid portion 89 provided in the second partition member main body 48 and the internal region 88 is sealed with respect to the pressure receiving chamber 60 and the equilibrium chamber 62. It has become. In the present embodiment, the same incompressible fluid as that enclosed in the fluid enclosure region 42 is also enclosed in the internal region 88.

  The bag-like rubber 72 is provided in the central portion in the radial direction of the partition member 44, and the opening (first communication hole 66) on the pressure receiving chamber 60 side of the orifice passage 70 is located on the outer peripheral side of the bag-like rubber 72. They are spaced apart. Further, the peripheral wall portion 74 of the bag-like rubber 72 has a support portion 78, which is an end portion on the partition member 44 side, positioned in the circular recess 50 of the first partition member main body 46. Thereby, the support part 78 of the bag-like rubber 72 is located on the radial extension line of the opening part on the pressure receiving chamber 60 side of the orifice passage 70 opening in the inner peripheral surface of the circular recess 50. In other words, the support portion 78 is opposed to the opening portion of the orifice passage 70 on the pressure receiving chamber 60 side in a part of the circumference and spaced apart in the radial direction.

  When the engine mount 10 having such a structure is mounted on the vehicle, the first mounting member 12 and the second mounting member 14 are relatively displaced by the shared load of the power unit. As a result, as shown in FIG. 2B, the contact surface 21 of the first mounting member 12 and the contacted surface 86 of the bag-shaped rubber 72 are brought into contact with each other via the main rubber elastic body 16. It comes to touch. Thereby, the bag-like rubber 72 is elastically deformed, and an auxiliary spring action for assisting the support spring of the main rubber elastic body 16 is exhibited. The first mounting member 12 and the bag-like rubber 72 may be in contact with each other in a non-mounted state on the vehicle, or may be opposed to each other with a predetermined distance after being mounted on the vehicle. Although good, in order to realize the durability of the bag-like rubber 72 and a stable contact state, it is desirable that the contact is made by mounting on the vehicle.

  When a low-frequency large-amplitude vibration corresponding to an engine shake is input while the vehicle engine mount 10 is mounted on the vehicle, the fluid flow through the orifice passage 70 is caused by the relative pressure fluctuation between the pressure receiving chamber 60 and the equilibrium chamber 62. Is produced, and the vibration isolation effect (high damping effect) based on the fluid flow action is exhibited.

  Further, the spring characteristics of the engine mount 10 can be adjusted with a higher degree of freedom by the auxiliary action of the spring of the bag-like rubber 72. That is, by appropriately adjusting the cross-sectional shape of the bag-like rubber 72 and the rubber material, it is possible to adjust the spring characteristics of the entire engine mount 10 without changing the spring characteristics and durability of the main rubber elastic body 16. It is.

  In addition, since the incompressible fluid is sealed in the inner region 88 formed inside the bag-like rubber 72 and the volume of the inner region 88 is kept constant, the bag-like rubber 72 is formed in the axial direction. At the same time as compressive deformation, it bulges and deforms in the radial direction. By such a diameter-enlarging deformation of the bag-like rubber 72, a radially outward piston action is exerted, and the sealed fluid in the pressure receiving chamber 60 opens radially inward at the outer peripheral edge of the partition member 44. The passage 70 is efficiently guided to the opening (first communication hole 66) on the pressure receiving chamber 60 side. Therefore, the amount of fluid flowing through the orifice passage 70 increases due to the elastic deformation of the bag-like rubber 72 accompanying the input of the vibration load, and the vibration isolation effect based on the fluid flow action can be advantageously exhibited.

  Furthermore, by utilizing the auxiliary spring action of the bag-like rubber 72, the rubber hardness of the main rubber elastic body can be set small. Therefore, a rubber material having a small static ratio (kd / ks) can be adopted as the rubber material of the main rubber elastic body, and the dynamic spring constant (kd) of the main rubber elastic body can be kept small. I can do it. As a result, it is possible to achieve an improvement in vibration isolation performance by reducing the dynamic spring while sufficiently securing a static spring rigidity for supporting the shared load of the power unit.

  As a result, the engine mount 10 having the structure according to the present embodiment has the first anti-vibration effect (high damping effect) against low-frequency large-amplitude vibration and the first anti-vibration effect (low dynamic spring effect) against high-frequency small-amplitude vibration. Both are effectively exhibited by the piston action and the auxiliary spring action of the bag-like rubber 72 in contact with the mounting member 12. Therefore, it is possible to obtain an effective anti-vibration effect against a plurality of types of vibrations in a wide frequency range.

  Further, the peripheral wall portion 74 of the bag-like rubber 72 has a reverse cup shape having a tapered connecting portion 80. Therefore, when the upper bottom portion 76 that is in contact with the first mounting member 12 is pushed down toward the equilibrium chamber 62, the peripheral wall portion 74 is likely to be bulged and deformed so as to protrude outward in the radial direction. Thus, by forming the bag-like rubber 72 with a specific vertical cross-sectional shape, the intended effect of improving the anti-vibration performance is effectively exhibited.

  Further, the peripheral wall portion 74 is formed with a concave groove 82 opened in the outer peripheral surface, and a partial thin portion is formed. As a result, deformation is likely to occur in the thin-walled portion, and the upper portion of the peripheral wall portion 74 is more likely to be deformed radially outward than the concave groove 82 is opened on the outer peripheral surface. . Therefore, the intended bulging deformation outward in the radial direction is more stably realized.

  In addition, the contacted surface 86 of the upper bottom portion 76 of the bag-like rubber 72 and the contact surface 21 of the first mounting member 12 (the central lower end surface of the main rubber elastic body 16 covering the contact surface 21) Is also a flat surface extending in the direction perpendicular to the axis. Therefore, the upper bottom portion 76 and the first mounting member 12 are stably in contact with each other, and the bag-like rubber 72 is elastically deformed into an intended shape.

  Further, the upper bottom portion 76 that contacts the first mounting member 12 in the bag-like rubber 72 is thicker than the peripheral wall portion 74. Therefore, breakage of the bag-like rubber 72 due to contact is advantageously avoided, and deformation of the contact part is suppressed, and generation of a hitting sound and contact in an unexpected deformation state are prevented.

  Further, the bag-like rubber 72 functions as an elastic stopper, and excessive approach displacement of the first mounting member 12 and the second mounting member 14 is restricted. As a result, the deformation of the main rubber elastic body 16 is restricted, and a decrease in durability due to the occurrence of cracks or the like is prevented. On the other hand, when the first mounting member and the second mounting member are excessively displaced, the upper bottom portion 76 of the bag-like rubber 72 can be separated from the main rubber elastic body 16. Can be prevented from being damaged by the action of an excessive tensile load.

  A compressive fluid such as air may be enclosed in the inner region 88 of the bag-like rubber 72. According to this, the volume of the bag-like rubber 72 becomes variable by utilizing the compressibility of the fluid sealed in the internal region 88. As a result, an anti-vibration effect (low dynamic spring effect) is exhibited based on the fluid pressure absorbing action due to the minute deformation of the bag-like rubber 72 when medium to high-frequency small-amplitude vibration such as idling vibration or traveling boom noise is input. In addition, when an excessive negative pressure is generated in the pressure receiving chamber 60 due to an input of a shocking large load due to overcoming a step, the pressure of the pressure receiving chamber 60 is compensated by the bulging deformation of the bag-like rubber 72, Occurrence of abnormal cavitation due to negative pressure in the pressure receiving chamber 60 is prevented.

  FIG. 3 shows an automobile engine mount 90 as a second embodiment of the fluid filled type vibration damping device structured according to the present invention. In the following description, members and portions that are substantially the same as those of the engine mount 10 shown in the first embodiment are denoted by the same reference numerals in the drawings, and description thereof is omitted.

  That is, the engine mount 90 includes a partition member 92 supported by the second mounting member 14. The partition member 92 includes a first partition member main body 46 and a second partition member main body 94.

  The second partition member main body 94 is a hard member having a thick and large-diameter substantially disk shape, and a second circumferential groove 58 is formed on the outer peripheral edge portion. In addition, an opening hole 96 as an anti-vibration control unit penetrating in the axial direction is formed in a central portion in the radial direction of the second partition member main body 94. The opening hole 96 has a circular cross section having a smaller diameter than the central hole 52 of the first partition member body 46. The opening hole 96 has a sufficiently larger passage cross-sectional area than the orifice passage 70 and a sufficiently short passage length, and its flow resistance is sufficiently smaller than that of the orifice passage 70.

  The partition member 92 is formed by overlapping the first partition member body 46 and the second partition member body 94 in the axial direction. Under the arrangement of the partition member 92 in the fluid sealing region 42, the upper opening of the opening hole 96 communicates with the inner region 88 of the bag-like rubber 72 protruding into the pressure receiving chamber 60 and the lower opening is balanced. It communicates with the chamber 62. In short, the inner region 88 of the bag-like rubber 72 is communicated with the equilibrium chamber 62 through the opening hole 96.

  In the automobile engine mount 90 having such a structure, when low frequency large amplitude vibration is input, the spring rigidity of the bag-like rubber 72 and the bulging deformation in the radial direction against the compressive deformation in the axial direction based on the specific shape. This restricts fluid flow through the opening hole 96. Therefore, the fluid flow through the orifice passage 70 is effectively induced, and the intended vibration isolation effect (low dynamic spring effect) is effectively exhibited.

  On the other hand, when the orifice passage 70 is substantially closed due to anti-resonance due to the input of medium to high frequency small amplitude vibration, a vibration isolation effect (low dynamic spring effect) due to minute deformation of the bag-like rubber 72 is expected. . Here, since the inner region 88 of the bag-like rubber 72 communicates with the equilibrium chamber 62 through the opening hole 96, the fluid pressure absorbing action due to the flexibility of the diaphragm 36 is exhibited, and the intended low dynamic spring The effect is exhibited effectively.

  Further, an excessive negative pressure in the pressure receiving chamber 60 due to an input of a shocking large load is prevented by the bulging deformation of the bag-like rubber 72. That is, when the pressure in the pressure receiving chamber 60 is relatively lowered with respect to the pressure in the equilibrium chamber 62, the encapsulated fluid in the equilibrium chamber 62 is passed through the opening hole 96 as the bag-shaped rubber 72 bulges and deforms. 72 flows into the inner region 88 of 72. As a result, the inner region 88 of the bag-like rubber 72 is maintained substantially constant without a significant drop in pressure, and is held in a state in which the bag-like rubber 72 can easily bulge and deform. Accordingly, the negative pressure in the pressure receiving chamber 60 is quickly and sufficiently reduced by the bulging deformation of the bag-like rubber 72, and the occurrence of abnormal cavitation noise is prevented.

  FIG. 4 shows an automobile engine mount 100 as a third embodiment of the fluid filled type vibration damping device structured according to the present invention. That is, the engine mount 100 includes a partition member 102 supported by the second mounting member 14. Furthermore, the partition member 102 is configured by overlapping a first partition member body 46 and a second partition member body 104 in the axial direction.

  The second partition member main body 104 is a hard member having a thick and large-diameter substantially disk shape. Further, a circular central recess 56 is formed in the radial center portion of the second partition member body 104. Further, a radial groove 106 is formed in the second partition member main body 104. The radial groove 106 is a groove that opens in the upper surface of the second partition member main body 104 and extends linearly in one radial direction, and has an inner peripheral end connected to the central recess 56. In addition, the end portion on the outer peripheral side is communicated with a part on the periphery of the second peripheral groove 58.

  The partition member 102 is formed by superimposing the first partition member body 46 on the upper surface of the second partition member body 104. In this partition member 102, the upper opening of the radial groove 106 formed in the second partition member main body 104 is covered with the first partition member main body 46 to form a passage extending in the radial direction. The passage communicates with the equilibration chamber 62 using the end of the orifice passage 70 on the equilibration chamber 62 side, and the anti-vibration control unit communicates the inner region 88 of the bag-like rubber 72 and the equilibration chamber 62 with each other. A second orifice passage 108 is formed. The second orifice passage 108 is tuned to a higher frequency than the orifice passage 70. In the present embodiment, the second orifice passage 108 is tuned to a medium frequency of about several tens of Hz corresponding to idling vibration.

  In the automobile engine mount 100 having such a structure, a fluid flow is generated through the second orifice passage 108 when a vibration corresponding to idling vibration is input, and a desired vibration isolation effect (low dynamic spring effect) is exhibited. It has come to be. That is, when a pressure fluctuation is applied to the pressure receiving chamber 60 due to vibration input, the pressure in the pressure receiving chamber 60 is transmitted to the inner region 88 of the bag-like rubber 72 by elastic deformation of the bag-like rubber 72. As a result, a relative pressure difference is generated between the inner region 88 and the equilibrium chamber 62, and fluid flow through the second orifice passage 108 is induced based on the pressure difference, thereby preventing the fluid based on the fluid flow action. The vibration effect is demonstrated.

  In the present embodiment, the passage communicating the inner region 88 of the bag-like rubber 72 and the equilibrium chamber 62 extends in the radial direction and in the circumferential direction, and the passage length is ensured longer than that in the second embodiment. Has been. Therefore, it is possible to set the tuning frequency of the passage to a lower frequency, whereby a second orifice passage 108 with medium frequency tuning can be realized. Needless to say, the passage length of the second orifice passage 108 can be freely adjusted by, for example, forming a communication hole downward from an intermediate portion of the radially extending portion, and the fluid can be adjusted with a wide degree of tuning freedom. Therefore, it is possible to obtain an anti-vibration effect based on the fluid action.

  As mentioned above, although embodiment of this invention was explained in full detail, this invention is not limited by the specific description. For example, the specific shape of the bag-like rubber is not limited to that shown in the embodiment. Specifically, the upper bottom portion may be the same thickness as the peripheral wall portion, and the concave groove 82 may not be formed in the support portion (the end portion on the partition member 44 side) of the peripheral wall portion. Further, the connecting portion of the peripheral wall portion (the end portion on the first attachment member 12 side) may not have a curved tapered cross section, may be a straight tube extending in the axial direction, or bend. It may be a tapered cylindrical shape that is inclined without doing so.

  Moreover, the bag-like rubber 72 may be configured such that the upper bottom portion 76 thereof comes into contact with the first mounting member 12 when mounted on the vehicle, or from the first mounting member 12 when mounted on the vehicle. It may be held in a separated state and come into contact with the first mounting member 12 by vibration input. Further, the upper bottom portion 76 of the bag-like rubber 72 is in contact with the first mounting member 12 in a non-mounted state on the vehicle, and the first mounting member 12 is pivoted with respect to the second mounting member 14. The contact between the bag-like rubber 72 and the first mounting member 12 may be released by being displaced in the direction.

  Further, in the structure (first embodiment) in which the inner region 88 of the bag-like rubber 72 is a sealed region, the fluid sealed in the inner region 88 is appropriately determined in consideration of the intended vibration-proof characteristics and the like. Any one of the same or different incompressible fluid as that enclosed in the fluid sealing region 42 or a compressive fluid such as air may be employed.

  Further, in the structure in which the inner region 88 of the bag-like rubber 72 is communicated with the equilibrium chamber 62 through the second orifice passage 108 (third embodiment), the specific structure of the second orifice passage is particularly limited. It is not a thing. For example, the second orifice passage may be formed as an independent flow path without using a part of the orifice passage 70.

  Further, the present invention is not only applied to a fluid-filled vibration isolator for automobiles, but also applied to a fluid-filled vibration isolator used for, for example, railway vehicles other than automobiles, industrial vehicles, and motorcycles. Is possible. Furthermore, the present invention is not only applied to engine mounts, but can be suitably applied to body mounts, subframe mounts, differential mounts, and the like.

10, 90, 100: Automotive engine mount, 12: First mounting member, 14: Second mounting member, 16: Rubber elastic body, 36: Diaphragm (flexible film), 44, 92, 102: Partition member, 60: pressure receiving chamber, 62: equilibrium chamber, 70: orifice passage, 72: bag-like rubber, 74: peripheral wall portion, 76: upper bottom portion, 82: concave groove, 88: inner region, 89: closing lid portion, 96: Opening hole, 108: Second orifice passage

Claims (6)

The first mounting member is disposed on one opening side of the second mounting member having a cylindrical shape, and the main rubber elastic body connects the first mounting member and the second mounting member. One opening of the second mounting member is closed, and the other opening of the second mounting member is closed with a flexible film, and is a partition member supported by the second mounting member A pressure receiving chamber in which a part of the wall is made of the main rubber elastic body and an equilibrium chamber in which a part of the wall is made of the flexible film are formed on both sides of the wall. In the fluid-filled vibration isolator in which an incompressible fluid is sealed in the chamber and the equilibrium chamber, and an orifice passage that communicates the pressure receiving chamber and the equilibrium chamber is formed.
An inverse cup-shaped bag-shaped rubber having a cylindrical peripheral wall portion and an upper bottom portion, which has a curved cross section that protrudes toward the outer peripheral side in the axial direction, is secured to the partition member by opening the peripheral edge portion thereof. Projecting from the central portion of the first mounting member toward the first mounting member, and the upper bottom portion of the first mounting member due to the approach displacement of the first mounting member and the second mounting member due to load input The cylindrical peripheral wall bulges and deforms in the radial direction by being pushed and elastically deformed by the pressure passage chamber, while the opening on the pressure receiving chamber side of the orifice passage allows the bag-shaped rubber to be The opening of the bag-shaped rubber in the partition member is provided so as to open radially inwardly at a position away from the cylindrical peripheral wall and radially opposed to the cylindrical peripheral wall portion of the bag-shaped rubber. The part determines the communication state between the inner region of the bag-like rubber and the equilibrium chamber Fluid filled type vibration damping device characterized by anti-vibration control unit is provided that.   The fluid-filled vibration isolator according to claim 1, wherein the vibration isolating control unit is a closed lid that seals an inner region of the bag-like rubber.   The fluid-filled vibration isolator according to claim 1, wherein the vibration isolating control unit is an opening hole that opens an internal region of the bag-like rubber to the equilibrium chamber.   The fluid-filled vibration isolator according to claim 1, wherein the vibration isolation control unit is a second orifice passage tuned to a higher frequency range than the orifice passage.   The fluid-filled type prevention according to any one of claims 1 to 4, wherein an end portion on the upper bottom portion side of the peripheral wall portion of the bag-shaped rubber has a tapered shape that decreases in diameter toward the upper bottom portion side. Shaker.   6. The groove according to claim 1, wherein a concave groove is formed at an end portion of the peripheral wall portion of the bag-like rubber on the partition member side and extends continuously over the entire circumference. The fluid-filled vibration isolator according to the item.

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