JP4270049B2 - Fluid filled vibration isolator - Google Patents

Description

  The present invention is a fluid-filled vibration isolator that obtains a vibration-proof effect based on the flow action of an incompressible fluid sealed inside, and is used in, for example, an automobile engine mount, body mount, and differential mount. The present invention relates to a fluid filled type vibration damping device that can be advantageously employed.

  Conventionally, as a kind of anti-vibration coupling body or anti-vibration support body interposed between members constituting the vibration transmission system, a first mounting member and a cylindrical shape opening toward the first mounting member A second mounting member provided with a portion is arranged opposite to each other, and the first mounting member and the second mounting member are connected by a main rubber elastic body. By covering the opening of the cylindrical portion of the second mounting member in a fluid-tight manner, a part of the wall portion is formed by the main rubber elastic body in the cylindrical portion of the second mounting member, so that the incompressible fluid is 2. Description of the Related Art There is known a fluid-filled vibration isolator that forms a sealed fluid chamber and obtains a vibration-proof effect based on a fluid action such as a resonance action of the sealed fluid at the time of vibration input. Further, in the fluid-filled vibration isolator, an umbrella member extending in a direction substantially orthogonal to the central axis of the cylindrical portion of the second mounting member is disposed in the fluid chamber, and the first mounting A structure in which the fluid chamber is divided into divided chambers located on both sides of the umbrella member by being supported by the member, and a narrow channel that connects the two divided chambers to each other is formed in the fluid chamber by the umbrella member. Has been proposed.

  In the fluid-filled vibration isolator provided with such an umbrella member, the first mounting member and the second mounting member as the main vibration input direction between the first mounting member and the second mounting member. When vibration is input in the opposite direction (substantially central axis direction of the cylindrical portion in the second mounting member), the umbrella member is displaced in the fluid chamber, and fluid flow through the constricted flow path is generated. By utilizing the fluid action such as the resonance action of the fluid, an effective vibration isolation effect can be obtained.

  However, in the conventional structure, the vibration-proofing effect based on the fluid action of the fluid that is caused to flow through the constricted flow path formed by the umbrella member is still not sufficiently exerted, and the low dynamic spring effect as particularly required is achieved. Sometimes it was difficult to achieve.

  Here, the present invention has been made in the background as described above, and the problem to be solved is that the vibration isolation effect based on the fluid flow action in the fluid chamber is more effectively exhibited. An object of the present invention is to provide a fluid-filled vibration isolator having an improved structure.

  Hereinafter, the aspect of this invention made | formed in order to solve such a subject is described. In addition, each aspect described below can be employed in any combination. In addition, it should be understood that the aspects and technical features of the present invention are not limited to those described below, but are recognized based on the description of the entire specification and the inventive concept described in the drawings. is there.

According to a first aspect of the present invention, a first mounting member and a second mounting member having a cylindrical portion that opens toward the first mounting member are arranged to be spaced apart from each other and opposed to each other. The first attachment member and the second attachment member are connected by a main rubber elastic body, and the opening of the cylindrical portion of the second attachment member is fluid-tightly covered with the main rubber elastic body. In the cylindrical part of the second mounting member, a part of the wall part is constituted by the main rubber elastic body to form a fluid chamber in which an incompressible fluid composed of a low viscosity fluid of 0.1 Pa · s or less is enclosed. In the fluid-filled vibration isolator, at least one pocket-shaped recess opening toward the fluid chamber is formed in the main rubber elastic body, and the bottom wall of the pocket-shaped recess reduces the thickness and facilitates elastic deformation. Of the thinned portion, and elastic deformation of the thinned portion Accordingly, fluid flow between the pocket-shaped recess and the fluid chamber is generated, and the pocket-shaped recess is formed in the circumferential direction of the main rubber elastic body with a diameter of the main rubber elastic body. The shape of the main body rubber elastic body is made to be substantially fan-shaped with the dimensions gradually increasing outward in the direction, and the thin wall portion is further centered on the wall portion of the fluid chamber formed by the main body rubber elastic body. The projected area ratio in the axial direction is 2 to 15% in size .

In such a fluid-filled vibration isolator according to the first aspect, the fluid flow with the pocket-shaped recess as a passage is caused by the elastic deformation of the thin wall portion at the time of vibration input. An effective anti-vibration effect can be obtained by utilizing a fluid action such as a resonance action of the fluid that is caused to flow in the recess. In particular, in such a fluid filled type vibration damping device, without increasing special parts, with a simple structure, Ru advantage there that it is possible to obtain the effect of improving the vibration damping ability using fluid flow action can .

Na us, specific shape of the main rubber elastic body, be one that is suitably determined depending on the required vibration damping characteristics, not restrictive. There may be many other, for example, thick disk shape The cylindrical rubber part of the second mounting member is fixed to the outer peripheral surface of the main body rubber elastic body, or the shape of the truncated cone protrudes outward in the opening direction from the cylindrical part of the second mounting member. Or, a thick tapered cylindrical main body rubber elastic body is adopted, and the first mounting member is fixed to the small-diameter end face, and the cylindrical portion of the second mounting member is attached to the large-diameter end peripheral face. The structure etc. which adhered can be used suitably.

Further, in the first aspect of the present invention, before Symbol thin portion, Ru Tei is formed with a substantially fan shape that spreads gradually in the circumferential direction toward the axis-perpendicular direction outward from the central axis of the main rubber elastic body. By employing the thin portion having such a shape, while suppressing the decrease in the spring stiffness of the main rubber elastic body, it become possible to advantageously ensure the area of the thin portion.

In particular, a first aspect mentioned above of the present invention, prior Symbol toward the fluid chamber side to form a pocket-like recess that opens the by the bottom wall of the pocket-like recess that constitutes the thin wall portion, characterized Tei Ru. In the fluid filled type vibration damping device according to this state-like, at the time of vibration input, along with the elastic deformation of the thin wall portion, through pocket-like recess, caused fluid flow between said pocket-like recess and the fluid chamber Will be. Therefore, by appropriately adjusting the cross-sectional area (opening area) and the passage length (depth) of the pocket-shaped recess as the fluid flow passage in consideration of the spring characteristics of the thin-walled portion, the pocket By using a fluid action such as a resonance action of a fluid that is caused to flow in the concave portion, it is possible to obtain a further excellent vibration isolation effect.

In this way using the pocket-like recess as a flow passage for fluid, in the case of obtaining a vibration damping effect based on resonance of the fluid in flowable passage, the resonance frequency of the fluid in the flow path, for example, umbrella member it is effective to tune to a frequency range higher than the resonance frequency of the fluid in the formed narrow flow path or the like by. Thereby, the effect of improving vibration damping characteristics thereof based on the low dynamic spring effect due to the flow passage and narrow flow path, etc., it is possible to obtained over a wider frequency range.

Furthermore, the first aspect described above of the present invention, the projected area of the front Symbol thin part, to the wall of the fluid chamber constituted by the main rubber elastic body, in the central axis direction of the rubber elastic body that it has a size of 2-15% per one ratio, that has features. By forming the thin portion with such a size, it is possible to more effectively obtain the effect of improving the anti-vibration characteristics by the thin portion while avoiding a significant decrease in the durability of the main rubber elastic body. . If the projected area ratio of the thin wall portion is smaller than 2%, it will be difficult to sufficiently improve the anti-vibration performance characteristics by the thin wall portion. On the other hand, if it exceeds 15%, the durability of the main rubber elastic body will be affected. There is a risk of getting out. In particular, by providing a pocket-like recess, in the case of utilizing the resonance of the fluid flowing the pocket-like recess, by the projected area ratio of the thin portion and 2-15%, the resonance action of the fluid Thus, the low dynamic spring effect based on the above can be obtained more advantageously.

Further, according to a second aspect of the present invention, in the fluid filled type vibration damping device according to the first aspect, a plurality of the thin portions are provided at substantially equal intervals around the central axis of the main rubber elastic body. , Feature. Such fluid-filled vibration damping device according to the second embodiment, by the fact that a plurality of thin portions, it is possible to obtain the effect of improving the vibration damping characteristics based on flow action of the fluid body to more advantageous At the same time, since the thin wall portion is divided and arranged, the supporting spring strength by the main rubber elastic body can be advantageously ensured. In particular, Ri by the fact that arranged at equal intervals a plurality of thin portions to the central axis of the main rubber elastic body, the flow is stabilized the flow body, also local stress concentration or the like in the main rubber elastic body Stable elastic deformation that is advantageously suppressed is generated, and thus the target vibration-proof performance can be obtained more stably.

  In the fluid-filled type vibration damping device according to the second aspect, preferably, the thin wall portion is opposed to each other in a direction perpendicular to the axis perpendicular to each other on the central axis of the main rubber elastic body. 4). By forming the thin wall portion in such an arrangement, in the main rubber elastic body, the portion where the thin wall portion is not formed is displaced by 45 degrees in the circumferential direction with respect to the opposing direction of the thin wall portion. Since two pairs are formed on the central axis of the body so as to face each other in the direction perpendicular to the axis perpendicular to each other, the spring rigidity in the direction perpendicular to the axis can be advantageously ensured.

A third aspect of the present invention, the first or second fluid-filled vibration damping device according to the state-like, said body from an outer peripheral portion of the rubber elastic body of the tubular portion of the second mounting member A cylindrical wall rubber that extends in the axial direction along the inner peripheral surface and is fixed to the cylindrical portion and covers the inner peripheral surface of the cylindrical portion is formed integrally with the main rubber elastic body, and the cylinder It is characterized in that the wall rubber is positioned so as to protrude from the outer peripheral edge portion of the thin wall portion toward the inner peripheral side in the portion excluding the formation portion of the thin wall portion. In such a fluid-filled vibration isolator according to the third aspect, the main body rubber elasticity is provided by the cylindrical wall rubber formed so as to extend from the outer peripheral portion of the main rubber elastic body along the inner peripheral surface of the cylindrical portion. A reinforcing support force is exerted on the outer peripheral portion of the body, whereby the decrease in the spring rigidity of the main rubber elastic body due to the provision of the thin portion can be reduced or eliminated. Moreover, since the cylindrical wall rubber has a small thickness dimension in the part where the thin rubber part is formed on the main rubber elastic body, the area of the thin wall part can be sufficiently secured, and the vibration isolation by the thin wall part is possible. The effect of improving the characteristics can also be obtained advantageously.

The fluid-filled vibration isolator according to the third aspect is preferably formed by extending from the main rubber elastic body in the axial direction along the inner peripheral surface of the cylindrical wall portion of the second mounting member. A rigid support member that supports the cylindrical wall rubber by contacting the cylindrical wall rubber with an axially extending front end surface (an end surface opposite to the main rubber elastic body in the axial direction). A structure that is fixedly provided with respect to the second mounting member is employed. By employing such a rigid support member, the reinforcing specific support effects exerted on the rubber elastic body by the cylindrical wall rubber, and thus be more effectively exhibited.

According to a fourth aspect of the present invention, in the fluid filled type vibration damping device according to any one of the first to third aspects, vibration between the first mounting member and the second mounting member is provided. A sub-fluid chamber in which an internal pressure difference relative to the fluid chamber is generated by the input is formed, and a fluid flow path that connects the fluid chamber and the sub-fluid chamber is provided. . According to such a fluid-filled vibration isolator according to the fourth aspect, an effective vibration isolating effect can be obtained based on a fluid action such as a resonance action of a fluid that is caused to flow in the fluid flow path. such fluid flow path, by tuning to a different frequency range than the narrow flow path or the like formed by the bevel member, it is possible to obtain a vibration damping effect superior to the vibration of the wider frequency range. Incidentally, tuning and vibration damping action by the fluid flow path, in order to obtain a vibration damping effect by formed umbrella member narrow flow path and the like more effectively, the fluid flow path to a lower frequency range than the narrow flow path and the like It is desirable to do.

  As the fluid flow path, for example, in addition to those formed in a continuous communication state, the fluid flow path can be opened and closed by opening / closing means such as a valve, or the partition plate disposed on the flow path is displaced or deformed. A fluid flow path having various structures such as a fluid flow that is allowed and a fluid flow amount is restricted by restricting a displacement amount and a deformation amount of the partition plate may be employed.

  Further, as the auxiliary fluid chamber, for example, an equilibrium chamber in which a part of the wall portion is formed of a flexible film such as a thin rubber film and the volume change is easily allowed can be suitably employed.

According to a fifth aspect of the present invention, in the fluid-filled vibration isolator according to the fourth aspect, a rigid partition member is internally fixed to the cylindrical portion of the second mounting member, and the partition member The fluid chamber is formed on one side of the substrate, the sub fluid chamber is formed on the other side, and the fluid flow path is formed by the partition member. By adopting such a configuration, the fluid chamber and the auxiliary fluid chamber, and further a fluid flow path, with a simpler structure, it is possible to form.

  In the fluid-filled vibration isolator having the structure according to the present invention as described above, a pocket-shaped recess is formed in the main rubber elastic body constituting the wall portion of the fluid chamber, and the thin wall portion is formed by the bottom wall portion. By configuring, when vibration is input, a significant increase in internal pressure of the fluid chamber is avoided based on the elastic deformation of the bottom wall, and the pocket-shaped recess acts as a fluid flow path, resulting in excellent vibration isolation effects. Can be obtained.

First, FIGS. 1 and 2 show an automobile engine mount 10 as a reference example of the present invention. The engine mount 10 has a structure in which a first mounting bracket 12 as a first mounting member and a second mounting bracket 14 as a second mounting member are elastically connected by a main rubber elastic body 15. Have. The first mounting bracket 12 is mounted on the power unit side, while the second mounting bracket 14 is mounted on the body side, so that the power unit is supported in a vibration-proof manner with respect to the body. Further, under such a mounted state, the engine mount 10 has the first mounting bracket 12 and the second mounting bracket 14 interposed between the first mounting bracket 12 and the second mounting bracket 14. The main vibration to be shaken is input in the substantially vertical direction in FIG.

  More specifically, the first mounting bracket 12 is formed of a rigid material such as metal and has a disk shape. The first mounting bracket 12 is welded with a substantially inverted conical support bracket 20 that protrudes downward in the axial direction. An umbrella as an umbrella member is attached to the protruding tip of the support bracket 20. The metal fitting 22 is fixed by caulking. The umbrella fitting 22 has a substantially disc shape, and the tip of the support fitting 20 is inserted into a mounting hole penetrating in the center and fixed by caulking, whereby the umbrella fitting 22 is fixed to the central axis of the support fitting 20. Are spread and supported in the orthogonal direction. Further, a bolt mounting hole 16 is provided in the central portion of the first mounting bracket 12, and a mounting bolt 18 is press-fitted and fixed to the bolt mounting hole 16 from the first mounting bracket 12. It protrudes upward in the middle. The first mounting bracket 12 is attached to the power unit side of an automobile (not shown) by the mounting bolt 18.

  On the other hand, the second mounting bracket 14 is formed of a rigid material such as metal and has a large cylindrical shape with a large diameter as a whole. The second mounting bracket 14 is disposed on the central axis of the first mounting bracket 12 so as to be spaced downward. Further, the second mounting bracket 14 is directed radially outward with respect to the opening peripheral edge on one axial direction (the upper side in FIG. 1 positioned on the first mounting bracket 12 side). An expanding flange-shaped portion 24 is integrally formed, and a locking portion 26 that is slightly bent inward in the radial direction is integrally formed at the peripheral edge of the opening in the other axial direction (downward in FIG. 1). ing. The second mounting member 14 is press-fitted and fixed to a rigid bracket 28 having a thick large-diameter cylindrical shape, and a bolt, for example, is attached to the body side of the automobile (not shown) via the bracket 28. It can be attached by, for example. The bracket 28 is integrally formed with an outward flange-like portion 30 at one peripheral edge of the opening in the axial direction. The flange-like portion 24 of the second mounting bracket 14 is formed with respect to the flange-like portion 30. By being superimposed, the load bearing strength in the load input direction of the power unit is set large.

Furthermore, a main rubber elastic body 15 is interposed between the first mounting bracket 12 and the second mounting bracket 14. The main rubber elastic body 15 has a substantially thick tapered ring shape or a cylindrical shape, and the outer peripheral surface is protruded upward in the axial direction while gradually reducing the diameter of the central portion. The shape is substantially a truncated cone. The main rubber elastic body 15 is vulcanized and bonded in a state where the first mounting bracket 12 is superposed on the small-diameter side end surface protruding upward in the axial direction, while the large-diameter side end outer peripheral surface. On the other hand, the second mounting bracket 14 is vulcanized and bonded on the inner peripheral surface of the upper opening end. Further, the support fitting 20 welded to the first attachment fitting 12 is disposed so as to penetrate the center hole 32 of the main rubber elastic body 15, and the support metal fitting 20 is located in the center hole 32 of the main rubber elastic body 15. It is vulcanized and bonded to the peripheral surface. In short, in this reference example , as shown in FIG. 3, the main rubber elastic body 15 is formed as an integrally vulcanized molded product 21 having the first and second mounting brackets 12 and 14. .

  The main rubber elastic body 15 extends along substantially the entire inner peripheral surface of the second mounting bracket 14 along the inner peripheral surface of the second mounting bracket 14. Thereby, on the inner peripheral surface of the second mounting member 14, a thick cylindrical wall rubber 34 that covers the entire upper part of the substantially central part in the axial direction is formed integrally with the main rubber elastic body 15. The main rubber elastic body 15 and the cylindrical wall rubber 34 cooperate to form a circular recess 36 that opens downward. Further, in the recess 36, the tip end portion of the support fitting 20 protrudes from the center of the upper bottom surface, and the umbrella fitting 22 supported by the support fitting 20 is positioned in the recess 36. . Further, the lower portion of the inner peripheral surface of the second mounting member 14 below the substantially central portion in the axial direction is covered with a thin seal rubber layer 38 formed integrally with the main rubber elastic body 15 and the cylindrical wall rubber 34. ing.

Furthermore, the main rubber elastic body 15 is directed inwardly (downward in FIG. 1) at its tapered portion positioned between the first mounting bracket 12 and the second mounting bracket 14. A pocket-shaped recess 31 having a predetermined depth is formed. The main rubber elastic body 15 is thinned at the site where the pocket-shaped recess 31 is formed, and the thickness is only the bottom wall 33 of the pocket-shaped recess 31. Here , the bottom wall portion 33 of the pocket-shaped recess 31 has a substantially constant thickness having a thickness dimension of about 1/4 to 1/3 of the thickness of the cylindrical wall portion of the main rubber elastic body 15. ing.

In addition, in the present reference example , four pocket-shaped recesses 31 are formed in the same shape as each other at substantially equal intervals in the circumferential direction around the central axis of the main rubber elastic body 15. In other words, two pairs of pocket-shaped recesses 31 are provided to be opposed to the main rubber elastic body 15 in a direction perpendicular to the axis perpendicular to each other. Each pocket-shaped recess 31 has a radial dimension over substantially the entire length of the main rubber elastic body 15 in the radial direction, and gradually increases in the circumferential direction as it goes outward in the radial direction of the main rubber elastic body 15. It is made into the substantially fan shape where becomes large. Further, each pocket-like recess 31 has an opening area (projected area in the axial direction of the main rubber elastic body 15) in the axial direction of the cylindrical wall portion formed by the main rubber elastic body 15, in other words, a circular shape. The area ratio is preferably 2 to 15%, more preferably 5 to 10% with respect to the axial projected area of the bottom surface of the recess 36.

In particular, in this reference example , the outer peripheral edge of the opening in the pocket-shaped recess 31 is positioned radially outward from the inner peripheral surface of the cylindrical wall rubber 34, and the pocket-shaped recess 31 is It extends to the wall rubber 34, and the inner peripheral portion of the cylindrical wall rubber 34 is partially cut out by the pocket-shaped recess 31. In short, the wall thickness of the cylindrical wall rubber 34 is reduced at the site where the pocket-shaped recess 31 is formed. In other words, in the portion where the pocket-shaped recess 31 is not formed, The wall thickness is increased, and the outer peripheral portion of the main rubber elastic body 15 is reinforced by the cylindrical wall rubber 34 having the increased wall thickness.

Moreover, in the present reference example , as described above, the pocket-shaped recesses 31 are formed in two pairs facing each other in the radial direction orthogonal to each other, so that the pocket-shaped recesses 31 are formed in the main rubber elastic body 15. The pair of thickened portions 39 are also formed in two pairs facing each other in the direction displaced in the circumferential direction by about 45 degrees with respect to the facing direction of the pocket-shaped recess 31. Therefore, the spring rigidity in the direction perpendicular to the axis can be advantageously obtained by these two pairs of thick portions 39 with little difference in each direction. In particular, for example, these two pairs of thick portions 39 are opposed to each other in a direction in which a relatively large axial perpendicular load is input, such as the longitudinal direction and the lateral direction of the automobile. This makes it possible to advantageously secure the spring rigidity.

  Further, the partition member 40 and the diaphragm 42 are sequentially inserted and assembled in such an integrally vulcanized molded product from the axially lower opening side of the second mounting bracket 14. The partition member 40 is formed of a hard material such as a metal material such as a synthetic resin material or an aluminum alloy, and has a substantially disk shape as a whole. The diaphragm 42 is formed of a thin rubber film that can easily be elastically deformed, and a cylindrical fitting ring 44 is vulcanized and bonded to the outer peripheral surface thereof. Then, the partition member 40 and the diaphragm 42 are inserted into the second mounting bracket 14 and arranged in the lower portion in the axial direction where the seal rubber layer 38 is formed. The partition member 40 and the diaphragm 42 (the fitting ring 44) are fitted and fixed to the second mounting member 14 by performing a diameter reduction process such as the above.

  As a result, the opening on the lower side in the axial direction of the second mounting bracket 14 is covered with the diaphragm 42 in a fluid-tight manner, and is hermetically sealed with respect to the external space inside the second mounting bracket 14. A fluid enclosure region in which a compressible fluid is enclosed is defined. As the sealing fluid, water, alkylene glycol, polyalkylene glycol, silicone oil, or a mixed fluid thereof may be used. In particular, in order to effectively obtain a vibration isolation effect based on the resonance action of the fluid. Is preferably a low-viscosity fluid of 0.1 Pa · s or less. In addition, injecting and filling the incompressible fluid is performed, for example, by assembling the partition member 40 and the diaphragm 42 to the second mounting bracket 14 given as an integrally vulcanized molded product in the incompressible fluid. Etc., which can be done advantageously.

  Further, the fluid sealing region is vertically divided into two by the partition member 40. Therefore, a part of the wall portion is composed of the main rubber elastic body 15 on the upper side across the partition member 40. A pressure receiving chamber 46 is formed as a fluid chamber in which a change in internal pressure is generated when vibration is input between the one mounting bracket 12 and the second mounting bracket 14. Further, on the lower side across the partition member 40, a part of the wall portion is constituted by a diaphragm 42, and a subfluid in which a change in volume is easily allowed based on the deformation of the diaphragm 42 and a pressure change is absorbed. An equilibrium chamber 48 as a chamber is formed. That is, the partition member 40 is inserted into the second mounting member 14 and is brought into contact with the lower end surface in the axial direction of the cylindrical wall rubber 34 over substantially the entire surface. As a result, the lower end surface in the axial direction of the cylindrical wall rubber 34 is supported by the partition member 40, and the reinforcing effect of the cylindrical wall rubber 34 on the main rubber elastic body 15 is improved. Is covered fluid-tightly by the partition member 40, and a pressure receiving chamber 46 is formed there.

Further, the partition member 40 is formed with a circumferential groove 50 that is open on the outer peripheral surface and extends substantially spirally in the circumferential direction, and the circumferential groove 50 is covered with the second mounting member 14. Thus, an orifice passage 52 is formed which communicates the pressure receiving chamber 46 and the equilibrium chamber 48 with each other. Then, based on the pressure difference generated between the pressure receiving chamber 46 and the equilibrium chamber 48 at the time of vibration input, a predetermined vibration isolating effect is exhibited by the fluid action of the fluid flowing through the orifice passage 52. . Here , based on the resonance action of the fluid flowing through the orifice passage 52, the flow passage cross-sectional area of the orifice passage 52 and the effective vibration-proofing effect against low-frequency vibration such as shake are exhibited. Length etc. are set.

Furthermore, a circular central recess 54 that opens upward is formed in the central portion of the partition member 40, and a movable rubber plate 56 as a partition plate is accommodated in the central recess 54. The movable rubber plate 56 is clamped and held in a fluid-tight manner in the axial direction by an annular retainer ring 58 fitted and fixed to the bottom wall of the central recess 54 and the opening of the central recess 54. Thus, it is assembled to the partition member 40. In such an assembled state, the upper surface of the central portion of the movable rubber plate 56 is exposed to the pressure receiving chamber 46 through the central through hole 60 of the presser ring 58, while the lower surface of the central portion of the movable rubber plate 56 is exposed. Is exposed to the equilibrium chamber 48 through a plurality of communication holes 62 penetrating the bottom wall of the central recess 54. The movable rubber plate 56 arranged in this way is subjected to the internal pressures of the pressure receiving chamber 46 and the equilibrium chamber 48 on the upper and lower surfaces. Therefore, when a vibration is input, the pressure difference between the pressure receiving chamber 46 and the equilibrium chamber 48 is increased. Based on the elastic deformation. Then, based on the elastic deformation of the movable rubber plate 56, fluid flow through the central through hole 60 and the communication hole 62 of the partition member 40 is generated, so that the resonance action of the fluid and the pressure absorption action of the pressure receiving chamber 46 are achieved. Based on this, the low dynamic spring effect with respect to the input vibration in the predetermined frequency range is exhibited. In addition, in this reference example , based on the fluid flow action accompanying the elastic deformation of the partition member 40, an anti-vibration effect effective against medium to high-frequency vibration such as idling vibration and low-speed booming noise is exhibited. The spring characteristics of the movable rubber plate 56, the length and cross-sectional area of the fluid flow path, etc. are set. Further, the elastic amount of elastic deformation of the movable rubber plate 56 is limited by its own elasticity and contact with the bottom of the central concave portion 54. When the low-frequency large-amplitude vibration such as a shake is input, the movable rubber plate 56 is movable. The amount of fluid flow associated with the elastic deformation of the rubber plate 56 is limited, and a sufficient amount of fluid flow through the orifice passage 52 is ensured.

  On the other hand, in the pressure receiving chamber 46 in which a part of the wall is defined by the main rubber elastic body 15, a direction orthogonal to the main vibration input direction (the mount center axis direction extending in the vertical direction in FIG. 1). Umbrella fittings 22 are arranged. Under the mounted state of the engine mount 10, as indicated by the phantom line in FIG. 1, the main rubber elastic body 15 is compressed and deformed by the input of the power unit weight, so that the umbrella bracket 22 is Are displaced downward from the state indicated by the solid line, and are positioned at a substantially central portion in the pressure receiving chamber 46. As a result, the interior of the pressure receiving chamber 46 is divided into two parts by the umbrella bracket 22, so that the upper divided chamber 70 and the lower divided chamber are arranged on both sides of the umbrella bracket 22 in the main vibration input direction (axial direction). 72 is formed. The upper divided chamber 70 and the lower divided chamber 72 are formed between opposing surfaces of the outer peripheral surface 66 of the umbrella bracket 22 and the inner peripheral surface 68 of the pressure receiving chamber 46 (the inner peripheral surface of the cylindrical wall rubber 34). Further, they are communicated with each other by an annular gap 64 extending continuously in the circumferential direction.

Here, in this reference example , as the umbrella fitting 22, substantially corresponding to the inner peripheral surface shape of the pressure receiving chamber 46 formed of the main rubber elastic body 15, the umbrella fitting 22 is obliquely downward from the central portion that is caulked and fixed to the support fitting 20. A taper or skirt is formed, and the outer peripheral portion extends in a short cylindrical shape downward in the axial direction. The outermost peripheral surface 66 has a support central axis ( A circular shape concentric with the central axis of the pressure receiving chamber 46). Further, the inner peripheral surface 68 of the peripheral wall portion of the pressure receiving chamber 46 in which the umbrella fitting 22 is accommodated is also formed in a substantially circular shape concentric with the central axis of the pressure receiving chamber 46. As a result, the annular space 64 between the radially opposed surfaces of the outer peripheral surface 66 of the umbrella bracket 22 and the inner peripheral surface 68 of the pressure receiving chamber 46 extends continuously over the entire circumferential direction with a substantially constant radial dimension. It has an annular shape.

In the engine mount 10 having the above-described structure in which the upper divided chamber 70 and the lower divided chamber 72 communicated by the annular gap 64 are formed by the umbrella bracket 22, the first mounting bracket 12 and the second mounting bracket 12 are connected. When vibration to be vibrated is input in a direction substantially opposite to the mounting bracket 14, the umbrella bracket 22 is displaced in the pressure receiving chamber 46, so that fluid flows through the annular gap 64 between the upper and lower divided chambers 70 and 72. Flow is produced. In short, in this reference example , the narrow channel is constituted by the annular gap 64, and a predetermined vibration isolating effect is exhibited based on the fluid flow action through the annular gap 64. It should be noted that the frequency range in which the low dynamic spring effect based on the resonance action of the fluid flowing through the annular gap 64 is taken into consideration is the flow in the annular gap 64 while considering the wall spring rigidity of the pressure receiving chamber 46 and the density of the enclosed fluid. Tuning can be achieved by adjusting the ratio of the channel cross-sectional area to the channel length. In particular, in this reference example , tuning may be performed in a higher frequency range (for example, high-speed booming noise) than the frequency range where the vibration isolation effect based on the fluid flow action accompanying the elastic deformation of the movable rubber plate 56 is exhibited. Desirably, it is possible to obtain an effective vibration-proofing effect against input vibrations in a wider frequency range in cooperation with the orifice passage 52 and the movable rubber plate 56 and the like.

  In addition, when the umbrella bracket 22 is displaced by vibration input, in the upper divided chamber 70, the internal pressure fluctuation of the upper divided chamber 70 is changed at the bottom wall portion 33 of the pocket-shaped recess 31 constituting a part of the wall portion. Accordingly, the elastic deformation accompanying the above can be generated relatively easily. Therefore, the displacement of the umbrella fitting 22 within the pressure receiving chamber 46 is advantageously caused, and a relative volume change between the upper divided chamber 70 and the lower divided chamber 72 is advantageously caused. As a result, the amount of fluid flowing through the annular gap 64 can be advantageously ensured. Therefore, the low dynamic spring effect based on the resonance action of the fluid that is caused to flow through the annular gap 64 is more effectively exhibited, and more excellent vibration isolation performance is exhibited.

In particular, in the present reference example , the pressure receiving chamber 46 is communicated with the equilibrium chamber 48 via the orifice passage 52 and the movable rubber plate 56, and the annular gap 64 is provided between the orifice passage 52 and the movable rubber plate 56. Since the tuning frequency is tuned to a higher frequency range than the tuning frequency, when the vibration is input in a high frequency range where an anti-vibration effect by the annular gap 64 is required, the upper wall is divided by elastic deformation of the bottom wall 33 of the pocket-shaped recess 31 As a result of the fluid flow between the chamber 70 and the lower divided chamber 72 being advantageously generated, fluid escape from the pressure receiving chamber 46 to the equilibrium chamber 48 via the orifice passage 52 and the movable rubber plate 56 is reduced. Will be prevented. Therefore, the amount of fluid flow through the annular gap 64 is advantageously ensured while sufficiently ensuring the anti-vibration effect against the input vibration in the low to medium frequency range that is exhibited based on the action of the orifice passage 52 and the movable rubber plate 56. Thus, it is possible to more advantageously obtain an anti-vibration effect against high-frequency vibration due to the resonance action of the fluid flowing through the annular gap 64.

Furthermore, in the present reference example , fluid flow through the pocket-shaped recess 31 is generated between the pressure receiving chamber 46 (upper chamber 70) with the elastic deformation of the bottom wall 33. Here, by adjusting the cross-sectional area and the flow path length of the pocket-shaped recess 31 in consideration of the expansion spring rigidity of the bottom wall portion 33, the density of the sealed fluid, etc., the pocket-shaped recess 31 flows. The low dynamic spring effect based on the resonance action of the fluid to be damped is tuned so as to be exhibited in the vibration frequency range to be damped.

  Specifically, for example, the low dynamic spring effect based on the resonance action of the fluid flowing through the pocket-shaped recess 31 is substantially the same as the low dynamic spring effect based on the resonance action of the fluid flowing through the annular gap 64. If tuning is performed in such a frequency range, the fluid flow amount through the annular gap 64 can be more advantageously secured in the tuning frequency range, thereby further improving prevention in a specific tuning frequency range. A vibration effect can be obtained.

  Alternatively, the low dynamic spring effect based on the resonance action of the fluid flowing through the pocket-shaped concave portion 31 and the low dynamic spring effect based on the resonance action of the fluid flowing through the annular gap 64 are, for example, several tens to several hundreds Hz. If the tuning is performed so that the frequency bands are different, the low dynamic spring effect based on the resonance action of the fluid can be obtained as a whole over a wide frequency range between these tuning frequency ranges. It is possible to obtain an effective anti-vibration effect against vibrations in a wide frequency range. In this case, it is desirable to set the tuning frequency of the fluid that is allowed to flow in the pocket-shaped recess 31 to be higher than the tuning frequency of the fluid that is allowed to flow in the annular gap 64.

Next, FIGS. 4 and 5 show an automobile engine mount 80 as one embodiment of the present invention. In the present embodiment, members and parts having the same structure as the engine mount 10 shown in FIG. 1 as the reference example described above are denoted by the same reference numerals as those of the engine mount 10 of the reference example . by referring to, their detailed description and it will be omitted.

That is, the engine mount 80 of this embodiment does not include the umbrella fitting (22) in the pressure receiving chamber 46 as compared to the reference example , and the pressure receiving chamber 46 is formed with a single fluid chamber structure. The constricted flow path (annular gap 64) is not formed in the inside.

In the engine mount 80 having such a structure, the anti-vibration effect against the input vibration in the low to medium frequency range, which is exhibited based on the action of the orifice passage 52 and the movable rubber plate 56, is the same as in the reference example. it is as it can be effectively exhibited. In addition, when a vibration is input in a high frequency range, a significant increase in the internal pressure of the pressure receiving chamber 46 can be avoided based on the elastic deformation of the bottom wall portion 33 of the pocket-shaped recess 31, so that a sudden increase in spring constant is avoided. Thus, a good anti-vibration effect can be maintained.

  In particular, since the pocket-shaped recess 31 acts as a fluid flow path, the cross-sectional area and the flow path length of the pocket-shaped recess 31 are appropriately adjusted so that the resonant action of the fluid that allows the pocket-shaped recess 31 to flow. By tuning so that the low dynamic spring effect is exerted in the vibration frequency range to be vibration-isolated, it becomes possible to obtain a particularly excellent vibration-proof effect for the input vibration in a specific high-frequency region. It is.

Incidentally, the vibration isolation characteristics of the engine mount 10 (FIG. 1) configured according to the reference example and the engine mount 80 (FIG. 4) configured according to the previous embodiment were measured, and the results are shown in FIG. This is also shown in FIG. Further, in the engine mount 10 having a structure according to the reference example , a mount having a structure in which the main rubber elastic body 15 is not provided with the pocket-shaped concave portion 31 and the same umbrella fitting 22 as that of the reference example is mounted is used as a comparative example. FIG. 6 shows the results of manufacturing and measuring the same anti-vibration characteristics for such a comparative example.

From the results shown in FIG. 6, in particular, in the engine mount 80 of the embodiment according to the present invention , an effective low dynamic spring effect is obtained in substantially the same manner as the comparative example in which the umbrella bracket is provided without the umbrella bracket. It can be understood that tuning can be performed to exhibit the low dynamic spring effect in the high frequency range rather than the frequency range in which the low dynamic spring effect is exhibited by the umbrella fitting. In addition, in the engine mount 10 of the reference example , compared with any of the one provided with only the umbrella bracket shown in the comparative example and the one provided only with the pocket-shaped recess shown in the embodiment according to the present invention. However, it is understood that a low dynamic spring effect can be advantageously achieved over a sufficiently wide frequency range.

As mentioned above, although embodiment of this invention has been explained in full detail, these are illustrations to the last, Comprising: This invention is not limited at all by the specific description in such embodiment.

For example , in the above-described embodiment, the vibration-proof orifice passage 52 for low-frequency vibration and the movable rubber plate 56 for vibration prevention for medium-frequency vibration are used. However, the orifice passage 52 and the movable rubber plate 56 are It is appropriately employed according to the required vibration isolation characteristics and the like, and is not essential in the present invention.

Further , the present invention can be similarly applied to various types of vibration isolators used other than automobile engine mounts, automobile body mounts, differential mounts, suspension bushings, or automobiles, thereby Any of the effects of the present invention can be effectively exhibited.

  In addition, although not listed one by one, the present invention can be implemented in a form added with various changes, modifications, improvements, etc. based on the knowledge of those skilled in the art. It goes without saying that all are included in the scope of the present invention without departing from the spirit of the invention.

It is a longitudinal cross-sectional view which shows the engine mount as a reference example of this invention, Comprising: It is a figure equivalent to the II cross section in FIG. It is II-II sectional drawing in FIG. It is a figure which shows the integral vulcanization molded product which comprises the engine mount shown by FIG. 1 with the longitudinal cross-section corresponding to FIG. It is a longitudinal cross-sectional view which shows the engine mount as one Embodiment of this invention, Comprising: It is IV-IV sectional drawing in FIG. It is VV sectional drawing in FIG. It is a graph which shows the measurement result of the vibration proof characteristic of the engine mount made into the structure according to FIG . 1 and FIG. 4 with a comparative example.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Engine mount 12 1st mounting bracket 14 2nd mounting bracket 15 Main body rubber elastic body 22 Umbrella bracket 31 Pocket-shaped recessed part 33 Bottom wall part 40 Partition member 42 Diaphragm 46 Pressure receiving chamber 48 Equilibrium chamber 52 Orifice passage 56 Movable rubber plate 64 Annular gap 70 Upper partition chamber 72 Lower partition chamber

Claims (6)

A first mounting member and a second mounting member having a cylindrical portion that opens toward the first mounting member are arranged to be spaced apart from each other, and the first mounting member and the second mounting member. The attachment member of the second attachment member is connected with a rubber elastic body and the opening of the tubular portion of the second attachment member is fluid-tightly covered with the rubber elastic body. In the fluid-filled vibration isolator, in which a part of the wall portion is formed of the main rubber elastic body and a fluid chamber is formed in which an incompressible fluid composed of a low-viscosity fluid of 0.1 Pa · s or less is sealed.
Forming at least one pocket-shaped recess opening toward the fluid chamber in the main rubber elastic body, and forming a thin-walled portion that is thinned and easily elastically deformed by a bottom wall of the pocket-shaped recess ; With the elastic deformation of the thin-walled portion, fluid flow between the pocket-shaped recess and the fluid chamber is generated , and the pocket-shaped recess is arranged in the circumferential direction of the main rubber elastic body. The main rubber elastic body has a substantially fan shape that gradually increases in size as it goes outward in the radial direction, and further, the thin wall portion is formed with respect to the wall portion of the fluid chamber constituted by the main rubber elastic body. A fluid-filled vibration isolator having a size of 2 to 15% per projected area ratio in the central axis direction of the main rubber elastic body.   The fluid-filled vibration isolator according to claim 1, wherein a plurality of the thin portions are provided at substantially equal intervals around the central axis of the main rubber elastic body. It extends in the axial direction from the outer peripheral portion of the main rubber elastic body along the inner peripheral surface of the cylindrical portion of the second mounting member, and is fixed to the cylindrical portion to cover the inner peripheral surface of the cylindrical portion. The cylindrical wall rubber is formed integrally with the main rubber elastic body, and the cylindrical wall rubber is positioned so as to protrude from the outer peripheral edge of the thin portion to the inner peripheral side in a portion excluding the portion where the thin portion is formed. fluid-filled vibration damping device according to claim 1 or claim 2 was allowed. A vibration input between the first mounting member and the second mounting member forms a secondary fluid chamber in which a relative internal pressure difference is generated with respect to the fluid chamber, and the fluid chamber and the secondary fluid. The fluid-filled vibration isolator according to any one of claims 1 to 3, further comprising a fluid flow path that communicates the chambers with each other. Said second partition member of the rigid tubular portion of the mounting member with interior fixed, the fluid chamber is formed on one side of sandwiching the partition member, together forming the secondary fluid chamber on the other side The fluid filled type vibration damping device according to claim 4, wherein the fluid flow path is formed by the partition member. The fluid according to any one of claims 1 to 5, wherein two pairs of the pocket-shaped concave portions are provided so as to face each other in a direction perpendicular to an axis perpendicular to the rubber elastic body. Enclosed vibration isolator.

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