JP2008249076A - Fluid sealed type vibration damper - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a fluid sealed type vibration damper having a structure advantageously securing durability of a movable membrane equipped with a short-circuiting slit for eliminating negative pressure while providing a desired vibration damping performance. <P>SOLUTION: In the fluid sealed type vibration damper, a liquid pressure absorbing mechanism is composed for absorbing pressure fluctuation of a pressure receiving chamber 78 by exerting pressure of the pressure receiving chamber 78 and an equilibration chamber 80 on each face of a movable rubber membrane 64 assembled to a partitioning member 44, the short-circuiting slot 72 is formed to penetrate the central portion of the movable rubber membrane 64 extended by a predetermined length, the short-circuiting slit 72 is held in a closed state, based on elasticity of the movable rubber membrane 64, and a valve mechanism is composed which becomes communicated when negative pressure is generated in the pressure receiving chamber 78 during input of vibration and the movable rubber membrane 64 is elastically deformed toward the pressure receiving side 78 side. Further, cracking preventing holes 76 are formed at both end portions of the short-circuiting slit 72 penetrating the movable rubber membrane 64 in the thickness direction, and the cracking preventing holes 76 are made to close in the state of being assembled to the partitioning member 44 of the movable rubber membrane 64. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an anti-vibration device that is suitably used as, for example, an engine mount of an automobile, and more particularly to a fluid-filled anti-vibration device that exhibits an anti-vibration effect based on the flow action of a fluid enclosed inside. The present invention relates to a vibration device.

  Conventionally, as a means for anti-vibration connection of one member to be anti-vibration connected to the other member, for example, the first attachment member is separated from one opening side of the second attachment member having a cylindrical portion. An anti-vibration device having a structure in which the first mounting member and the second mounting member are connected to each other with a main rubber elastic body is known. In addition, in order to obtain an excellent anti-vibration effect against vibrations in a specific frequency range in question, a fluid-filled vibration-proof device utilizing the anti-vibration effect based on the fluid action of the fluid enclosed inside has also been proposed. ing.

  That is, as shown in Patent Document 1 (Japanese Patent No. 2805305), for example, the fluid-filled vibration isolator is configured such that the first mounting member is one of the second mounting members having a cylindrical portion. A pressure receiving chamber in which the partition member is supported by the second mounting member and a part of the wall portion is formed of the main rubber elastic body on one side across the partition member while being spaced apart from the opening side. And forming an equilibrium chamber in which a part of the wall is made of a flexible film on the other side across the partition member, and enclosing an incompressible fluid in the pressure receiving chamber and the equilibrium chamber The pressure receiving chamber and the equilibrium chamber are provided with an orifice passage that communicates with each other. According to such a fluid-filled vibration isolator, when vibration is input, the relative pressure between the pressure receiving chamber in which the internal pressure fluctuation occurs and the equilibrium chamber in which the volume change is allowed and maintained at substantially atmospheric pressure. Variations are produced. Such relative pressure fluctuations cause fluid flow through an orifice passage that communicates the two chambers with each other, and an excellent vibration-proofing effect based on the fluid flow action is exhibited.

  However, for example, when the fluid-filled vibration isolator as described above is employed as an engine mount for an automobile, the frequency of the input vibration changes depending on the running state of the automobile. Therefore, when vibration in the tuning frequency range of the orifice passage is input, an effective anti-vibration effect is exhibited based on the fluid flow action, while when vibration in a frequency range higher than the tuning frequency is input, There was a problem that the vibration-proof performance deteriorated due to the orifice passage being substantially closed.

  Therefore, in Patent Document 1 or the like, a movable membrane that divides the pressure receiving chamber and the equilibrium chamber is assembled to the partition member, and a higher frequency than the tuning frequency range of the orifice passage is utilized by utilizing a hydraulic pressure absorbing action due to minute deformation of the movable membrane. There has been proposed a structure capable of obtaining an effective anti-vibration effect against vibrations in the region.

  By the way, in the conventional fluid-filled vibration isolator, when a large vibration is input between the first mounting member and the second mounting member, there is a possibility that abnormal noise or vibration may occur. For example, when a fluid-filled vibration isolator is used as an engine mount for an automobile, a shocking vibration load is applied between the first mounting member and the second mounting member when traveling on an uneven wavy road. May be generated, causing abnormal noise and vibration that can be felt by the passenger.

  The mechanism for generating such abnormal noise and vibration has not been sufficiently clarified yet, but a shocking vibration load with a large acceleration is input between the first mounting member and the second mounting member. Then, bubbles that are understood as cavitation are generated in the pressure receiving chamber. Then, the explosive micro jet formed when the bubbles collapse is propagated to the first mounting member and the second mounting member as water hammer pressure, and is transmitted to the vehicle body. It is thought that sound and vibration are generated. Therefore, it is effective to reduce or avoid abnormal noise and vibration caused by cavitation as soon as possible to eliminate the negative pressure generated in the pressure receiving chamber when an impact load is input.

  Therefore, as one method for reducing or avoiding such abnormal noise and vibration, in the fluid-filled vibration isolator disclosed in Patent Document 1, a movable chamber is provided so as to partition the pressure receiving chamber and the equilibrium chamber. A structure in which a slit as a short-circuit hole is formed in a film has been proposed. In such a fluid-filled vibration isolator described in Patent Document 1, when a shocking vibration load is input between the first mounting member and the second mounting member and a negative pressure is generated in the pressure receiving chamber, the movable vibration isolator is movable. The slit formed in the membrane is opened, and the pressure receiving chamber and the equilibrium chamber are short-circuited through the slit, so that the negative pressure in the pressure receiving chamber is quickly eliminated.

  However, like the fluid-filled vibration isolator shown in Patent Document 1, when the slit is formed in the movable film formed of a rubber elastic body, the opening and closing of the slit accompanying the elastic deformation of the movable film is repeated, The movable film is easily cracked at both ends in the longitudinal direction of the slit, and it is difficult to sufficiently ensure the durability of the movable film.

Japanese Patent No. 2805305

  Here, the present invention has been made in the background as described above, and the problem to be solved is a short-circuit slit for eliminating negative pressure while effectively realizing the desired vibration isolation performance. It is an object of the present invention to provide a fluid-filled vibration isolator having a novel structure that can advantageously ensure the durability of a movable rubber film provided with the above.

  Hereinafter, the aspect of this invention made | formed in order to solve such a subject is described. In addition, the component employ | adopted in each aspect as described below is employable by arbitrary combinations as much as possible. Further, aspects or technical features of the present invention are not limited to those described below, but are described in the entire specification and drawings, or an invention that can be understood by those skilled in the art from those descriptions. It should be understood that it is recognized based on thought.

  That is, according to the present invention, the first mounting member is spaced from one opening side of the second mounting member having a cylindrical portion, and the first mounting member and the second mounting member are elastic on the main body. By being connected to each other by the body, one opening of the second mounting member is closed by the main rubber elastic body, and the other opening of the second mounting member is made of a flexible membrane. A partition member that is closed and sealed between the main rubber elastic body and the flexible membrane to form an incompressible fluid chamber and is supported by the second mounting member. The fluid chamber is divided into two parts, and a pressure receiving chamber in which a part of the wall portion is formed of the main rubber elastic body is formed on one side across the partition member, and the other side across the partition member is formed. An equilibration chamber is formed on the side with a part of the wall made of the flexible membrane. In the fluid-filled vibration isolator having an orifice passage communicating with each other, a movable rubber film is assembled to the partition member, and the pressure of the pressure receiving chamber is exerted on one surface of the movable rubber film. A hydraulic pressure absorption mechanism is constructed in which the pressure in the equilibrium chamber is exerted on the other surface, and the pressure variation in the pressure chamber is absorbed by elastic deformation of the movable rubber film based on the pressure difference between the pressure chamber and the equilibrium chamber. In addition, a short-circuit slit extending in a predetermined length is formed in the central portion of the movable rubber film so as to penetrate the movable rubber film, and the short-circuit slit is held in a closed state based on the elasticity of the movable rubber film. In addition, a valve mechanism is configured in which a predetermined negative pressure is induced to the pressure receiving chamber when vibration is input, and the movable rubber film is elastically deformed toward the pressure receiving chamber side to be in a communication state. , Further In addition, a crack prevention hole penetrating the movable rubber film in the thickness direction is formed at both end portions of the short-circuit slit, and the crack prevention hole is attached to the partition member when the movable rubber film is assembled to the partition member. Is blocked.

  In such a fluid-filled vibration isolator having a structure according to the present invention, a short-circuit slit is formed through the movable rubber film constituting the hydraulic pressure absorption mechanism, and the inside of the pressure-receiving chamber is input by an impact vibration load. When the pressure is greatly reduced, a short-circuit slit is opened, and fluid flow through the short-circuit slit is generated between the pressure receiving chamber and the equilibrium chamber. By the fluid flow through the short-circuit slit, the negative pressure in the pressure receiving chamber is eliminated as quickly as possible, and abnormal noise and vibration that are considered to be caused by the pressure drop in the pressure receiving chamber are effectively reduced or avoided. It has become.

  Moreover, according to the present invention, it is possible to advantageously prevent the occurrence of cracks that are likely to cause problems at both ends of the short-circuit slit that opens and closes in response to input vibration. That is, crack prevention holes that penetrate the movable rubber film in the thickness direction are formed at both ends of the short-circuit slit. As a result, when the short-circuit slit is opened, the tensile force in the slit width direction is prevented from being exerted on the movable rubber film at both ends of the short-circuit slit, and cracks are generated at both ends of the short-circuit slit in the movable rubber film. This can prevent the movable rubber film from tearing. Therefore, the durability of the movable rubber film having the short-circuit slit can be advantageously ensured, and the opening / closing operation of the short-circuit slit can be stably realized.

  Further, the crack prevention hole is closed under the assembled state of the movable rubber film to the partition member. Therefore, when inputting the vibration to be isolated, the sealed fluid is prevented from flowing between the pressure receiving chamber and the equilibrium chamber through the crack prevention hole, and based on the fluid action of the fluid that flows between the two chambers through the orifice passage. An anti-vibration effect can be obtained effectively.

  Further, in the fluid filled type vibration isolator having a structure according to the present invention, the movable rubber film is provided with reinforcing portions which are thicker than the other portions at both end portions of the short-circuit slit, and the reinforcement A structure in which the crack prevention hole is formed so as to penetrate the portion is preferably employed.

  Thus, by providing a reinforcing part at the part where the crack prevention hole is formed in the movable rubber film and making the movable rubber film partially thick, at both ends of the short-circuit slit where the occurrence of cracks is likely to be a problem. The durability of the movable rubber film can be improved, and the occurrence of cracks at the location can be prevented more advantageously.

  Further, in the fluid filled type vibration damping device having the structure according to the present invention, the opening portion on the equilibrium chamber side of the crack preventing hole is closed under the assembled state of the movable rubber film to the partition member. It is desirable that

  In this way, by closing the opening of the equilibrium chamber side by closing the crack prevention hole, when a positive pressure is exerted in the pressure receiving chamber, the movable rubber film moves toward the equilibrium chamber side by the pressure in the pressure receiving chamber. It is elastically deformed to protrude. As a result, the anti-cracking hole is stably held in the closed state, and the vibration isolation effect based on the fluid action of the fluid that flows through the orifice passage is effectively exhibited.

  In the fluid filled type vibration damping device according to the present invention, it is preferable that the short-circuit slit extends linearly through the center of the movable rubber film.

  By adopting such a structure and providing a short-circuit slit so as to pass through the center of the movable rubber film, a large opening of the short-circuit slit can be secured. Therefore, when a predetermined negative pressure is induced in the pressure receiving chamber, the amount of fluid flow between the pressure receiving chamber and the equilibrium chamber is advantageously secured through the short-circuit slit, and the negative pressure in the pressure receiving chamber is quickly eliminated. I can do it. Accordingly, it is possible to more advantageously reduce or avoid abnormal sounds and vibrations that are considered to be caused by cavitation.

  Further, in the fluid filled type vibration damping device according to the present invention, the outer peripheral edge of the movable rubber film is supported by the partition member, and the crack prevention hole formed in the movable rubber film is formed by the partition member. The crack prevention hole may be closed by being overlaid on the opening of each other.

  According to this, by supporting the outer peripheral edge portion of the movable rubber film with the partition member, the elastic deformation in the central portion of the movable rubber film in which the short-circuit slit is formed is allowed, and the hydraulic pressure due to the elastic deformation of the movable rubber film is allowed. Use the partition member that supports the outer peripheral edge of the movable rubber film, and closes the crack prevention holes formed at both ends of the short-circuit slit without adopting a special member, while realizing the absorption effect advantageously. I can do it.

  Hereinafter, in order to clarify the present invention more specifically, embodiments of the present invention will be described in detail with reference to the drawings.

  First, FIG. 1 shows an automobile engine mount 10 as an 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 bracket 12 as a first mounting member and a second mounting bracket 14 as a second mounting member are connected by a main rubber elastic body 16. The first mounting bracket 12 is attached to a power unit (not shown) that is one member constituting the vibration transmission system, and the second mounting bracket 14 is a vehicle body (not shown) that is the other member constituting the vibration transmission system. As a result, the engine mount 10 is interposed between the members constituting the vibration transmission system, and the power unit is supported in a vibration-proof manner by the vehicle body. In the following description, the vertical direction means the vertical direction in FIG. 1 which is the main vibration input direction in principle. FIG. 1 shows an engine mount 10 that is not attached to an automobile.

  More specifically, the first mounting bracket 12 is made of a rigid material such as iron or aluminum alloy, and has a substantially circular block shape. Further, a flange portion 18 that extends radially outward is integrally formed at the upper end portion of the first mounting member 12. Further, a bolt hole 20 is formed so as to open on the upper end surface of the first mounting member 12 and extend on the central axis, and an internal thread is engraved on the inner peripheral surface of the bolt hole 20. Such a first mounting bracket 12 is bolted to a power unit (not shown) by a mounting bolt (not shown) screwed into the bolt hole 20, for example.

  On the other hand, the second mounting bracket 14 is formed of a rigid material similar to that of the first mounting bracket 12 and has a thin cylindrical shape with a large diameter. In addition, a constricted portion 22 is provided at an intermediate portion in the axial direction of the second mounting bracket 14. The constricted portion 22 includes a tapered portion 24 that gradually decreases in diameter toward the lower side in the axial direction, and a stepped portion 26 that widens from the lower end portion of the tapered portion 24 toward the outer peripheral side. Further, a step 28 that extends toward the outer peripheral side is formed at the lower end of the second mounting bracket 14, and a large-diameter cylindrical caulking piece 29 that extends downward from the outer peripheral edge of the step 28 is formed. It is integrally formed. Such a second mounting bracket 14 is fixed to the vehicle body, for example, by attaching a bracket (not shown) fitted and fixed to the second mounting bracket 14 to the vehicle body.

  The first mounting bracket 12 and the second mounting bracket 14 are disposed on the same central axis, and the first mounting bracket 12 is spaced apart from the second mounting bracket 14 in the axial direction. Be placed. The main rubber elastic body 16 is interposed between the first mounting metal 12 and the second mounting metal 14, so that the first mounting metal 12 and the second mounting metal 14 are connected to the main rubber elastic body. 16 is elastically connected.

  The main rubber elastic body 16 is formed of a rubber elastic body having a thick, substantially truncated cone shape. A large-diameter circular recess 30 is formed in the central portion of the main rubber elastic body 16 in the radial direction so as to open to the large-diameter side end surface (the lower end surface in FIG. 1). The first mounting bracket 12 is embedded in the end portion of the main rubber elastic body 16 on the small diameter side, and the lower surface of the flange portion 18 is overlapped with the end surface of the main rubber elastic body 16 on the small diameter side. It is vulcanized and bonded. On the other hand, on the outer peripheral surface of the large-diameter end of the main rubber elastic body 16, the upper end portion of the second mounting bracket 14 and the taper portion 24 are overlapped and vulcanized and bonded. Thereby, the first mounting bracket 12 and the second mounting bracket 14 are connected to each other by the main rubber elastic body 16. In addition, the main rubber elastic body 16 in the present embodiment is formed as an integrally vulcanized molded product that integrally includes the first mounting bracket 12 and the second mounting bracket 14.

  Further, a seal rubber layer 32 integrally formed with the main rubber elastic body 16 is fixed to the inner peripheral surface of the second mounting bracket 14. The seal rubber layer 32 is formed of a thin rubber film, and is formed so as to cover a portion from the inner peripheral surface of the step portion 26 to the inner peripheral portion of the step 28 in the second mounting bracket 14.

  In addition, a diaphragm 34 as a flexible film is disposed at the lower end opening of the second mounting bracket 14. The diaphragm 34 is formed of a rubber film having a thin, large-diameter, generally circular dome shape, so that elastic deformation is easily allowed. A fixing metal fitting 36 is fixed to the outer peripheral edge of the diaphragm 34. The fixing bracket 36 has a substantially annular shape, and integrally includes a cylindrical fixing portion 38 and a caulking portion 40 that spreads from the upper end of the fixing portion 38 toward the outer peripheral side. Then, the outer peripheral edge of the diaphragm 34 is vulcanized and bonded to the fixing portion 38 of the fixing bracket 36, whereby the diaphragm 34 is formed as an integrally vulcanized molded product integrally provided with the fixing bracket 36. In the present embodiment, the fixing bracket 36 is covered with a rubber layer integrally formed with the diaphragm 34 over substantially the entire surface excluding the outer peripheral edge portion and the upper end surface of the caulking portion 40.

  Such a diaphragm 34 is assembled to the second mounting bracket 14. That is, the outer peripheral edge portion of the caulking portion 40 of the fixing bracket 36 is overlapped from below with respect to the step 28 provided at the lower end portion of the second mounting bracket 14, and the caulking portion 40 is overlapped with the second mounting bracket 14. The diaphragm 34 is fixed to the lower end portion of the second mounting bracket 14 by being caulked and fixed by a caulking piece 29 formed integrally with the second mounting bracket 14.

  As described above, the diaphragm 34 is assembled to the integrally vulcanized molded product of the main rubber elastic body 16 including the first mounting bracket 12 and the second mounting bracket 14, so that the shaft of the second mounting bracket 14 can be obtained. The opening on the upper side in the direction is closed fluid-tightly by the main rubber elastic body 16, and the opening on the lower side in the axial direction of the second mounting bracket 14 is closed fluid-tightly by the diaphragm 34. Thus, a fluid sealing region 42 as a fluid chamber sealed from the outside is formed between the main rubber elastic body 16 and the diaphragm 34 on the inner peripheral side of the second mounting bracket 14. Further, in the fluid sealing region 42, an incompressible fluid such as water, alkylene glycol, polyalkylene glycol, silicone oil, or a mixture thereof is sealed as a sealing fluid. The sealed fluid is not particularly limited, but the viscosity is 0.1 Pa · s or less in order to advantageously obtain a vibration isolation effect based on the resonance action of the fluid flowing through the orifice passage 82 described later. It is desirable to employ a low viscosity fluid. In addition, the fluid is sealed in such a manner that the diaphragm 34 is assembled to the second mounting bracket 14 (an integrally vulcanized molded product of the main rubber elastic body 16 provided with the second mounting bracket 14). It can be realized advantageously by performing in.

  A partition member 44 is accommodated in the fluid sealing area 42. The partition member 44 has a thick, substantially disk shape, and includes a partition metal body 46 and a lid metal 48 in the present embodiment.

  The partition metal fitting body 46 as a whole has a thick, substantially disk shape, and its outer peripheral edge projects downward. In addition, a circumferential groove 52 is formed in a radially intermediate portion of the partition fitting body 46. The circumferential groove 52 is a concave groove that opens on the upper surface of the partition metal body 46 and is formed to extend in the circumferential direction by a predetermined length.

  In addition, a circular central recess 54 that opens upward is formed in the central portion in the radial direction of the partition metal fitting 46, and a central hole 56 that passes through the center of the bottom wall portion of the central recess 54. Is formed. The central hole 56 has a certain circular cross section and is formed so as to penetrate the radial center portion of the partition fitting body 46. Further, a lid protrusion 58 is integrally formed with the partition metal body 46 at the opening peripheral edge of the central hole 56. The lid protrusion 58 has an annular shape extending in the circumferential direction, and protrudes upward from the inner peripheral edge portion of the bottom wall portion of the central recess 54. In addition, by providing the lid protrusion 58 on the inner peripheral edge of the partition metal fitting 46, the entire circumference extends in the circumferential direction by the cooperation of the wall of the cover protrusion 58 and the central recess 54 and upward. A concave groove is provided that opens toward the front.

  On the other hand, the lid metal fitting 48 is a thin-walled large-diameter plate, and in this embodiment, has a stepped disk shape in which the central portion is positioned above the outer peripheral portion. Further, a through hole 60 is formed in the central portion of the lid metal 48 in the radial direction. The through hole 60 is a circular hole formed with a diameter substantially equal to the central hole 56 of the partition metal fitting 46, and is formed so as to penetrate the radial center portion of the lid metal 48 in the plate thickness direction. A support protrusion 62 is integrally formed on the opening peripheral edge of the through hole 60. The support protrusion 62 has an annular shape extending over the entire circumference, and is formed so as to protrude downward from the inner peripheral edge of the lid fitting 48.

  The lid metal 48 is overlapped and combined with the upper end surface of the partition metal body 46 from above. As a result, the upper opening of the circumferential groove 52 formed so as to open to the upper end surface of the partition metal body 46 is covered with the lid metal 48 to form a tunnel-like flow path extending in a predetermined length in the circumferential direction. Has been.

  A movable rubber film 64 is disposed between the partition metal body 46 and the cover metal 48. As shown in FIGS. 2 to 4, the movable rubber film 64 is formed of a substantially disc-shaped rubber elastic body, and the outer peripheral edge portion has an annular shape that is thicker than the central portion. A support portion 66 is integrally formed.

  Furthermore, a short-circuit slit 72 is formed in the movable rubber film 64. The short-circuit slit 72 in the present embodiment is a notch that extends linearly in one radial direction so as to pass through the center of the movable rubber film 64 and penetrates the movable rubber film 64 in the plate thickness direction. It is formed in the position slightly spaced apart to the inner peripheral side with respect to the annular support part 66 formed in the outer peripheral edge part.

  Furthermore, reinforcing portions 74 and 74 are formed on both sides in the longitudinal direction of the short-circuit slit 72. The reinforcing portion 74 has a substantially semicircular shape in plan view, and is thicker than other portions in the central portion of the movable rubber film 64. In particular, in the present embodiment, the movable rubber film 64 is partly protruded downward in the reinforcing portion 74 so as to be thick, and the lower end surface of the reinforcing portion 74 is a substantially flat surface extending in the direction perpendicular to the axis. Yes.

  A crack prevention hole 76 is formed in the reinforcing portion 74 of the movable rubber film 64. The crack prevention hole 76 is a small-diameter circular hole formed through each of the forming portions of the pair of reinforcing portions 74 and 74 in the movable rubber film 64, and is formed on both sides in the longitudinal direction of the short-circuit slit 72. Further, in the present embodiment, both end portions in the longitudinal direction of the short-circuit slit 72 are formed so as to reach the crack prevention holes 76 and 76.

  The movable rubber film 64 according to this embodiment is sandwiched between the partition metal body 46 and the lid metal 48 and assembled to the metal fittings 46 and 48. That is, the movable rubber film 64 is fitted in the central recess 54 formed in the central portion of the partition metal body 46, and the annular support portion 66 provided on the outer peripheral edge of the movable rubber film 64 is the central recess 54. The annular support portion 66 is sandwiched between the partition metal body 46 and the lid metal 48 that is superimposed on the partition metal body 46 from above while being positioned and supported between the peripheral wall portion and the radial direction of the lid protrusion 58. Thus, the movable rubber film 64 is fixedly attached to the partition metal body 46 and the lid metal 48.

  When the movable rubber film 64 is assembled to the partition metal body 46 and the lid metal 48, the central hole 56 formed in the partition metal body 46 and the through-hole 60 formed in the lid metal 48 serve as the movable rubber film. It is blocked by 64. Thereby, the partition member 44 according to the present embodiment including the movable rubber film 64 is configured.

  Further, the protruding front end surface of the lid protrusion 58 provided on the inner peripheral edge of the partition metal body 46 is overlapped with the crack prevention hole 76 from below, so that the partition metal body 46 and the lid of the movable rubber film 64 are covered. The crack prevention hole 76 is closed in the assembled state to the metal fitting 48. In particular, in the present embodiment, reinforcing portions 74 and 74 projecting toward the balance chamber 80 described later are formed at the portions where the crack preventing holes 76 and 76 are formed in the movable rubber film 64, and on the periphery of the movable rubber film 64. The portions where the reinforcing portions 74 and 74 are formed are brought into contact with the lid ridge 58, and the outer peripheral portion outside the reinforcing portions 74 and 74 is positioned so as to be spaced apart upward from the lid ridge 58.

  The partition member 44 having such a structure is supported by the second mounting bracket 14 and accommodated in the fluid sealing region 42. That is, before the diaphragm 34 is assembled to the second mounting bracket 14, the partition member 44 is inserted into the second mounting bracket 14 from the lower opening and provided to the second mounting bracket 14. The stepped portion 26 is brought into contact with the stepped portion 26 through the seal rubber layer 32 from below. Then, by subjecting the second mounting bracket 14 to diameter reduction processing such as an eight-way drawing, the partition member 44 is fitted and fixed to the second mounting bracket 14 to be supported. In the present embodiment, the diaphragm 34 is assembled to the second mounting bracket 14 in a state where the partition member 44 is assembled to the second mounting bracket 14, and the inner peripheral edge of the caulking portion 40. The upper surface of the part is brought into contact with the lower surface of the outer peripheral edge of the partition metal body 46, whereby the diaphragm 34 and the partition member 44 are relatively aligned, and the partition member 44 is in the axial direction of the stepped part 26 and the fixing metal 36. It is positioned between them.

  Further, the partition member 44 is supported by the second mounting bracket 14 via the seal rubber layer 32, so that the partition member 44 and the second mounting bracket 14 are sealed in a fluid-tight manner. Is assembled to the second mounting bracket 14. Thus, in the assembled state in which the partition member 44 is accommodated and disposed in the fluid sealing region 42, the fluid sealing region 42 is divided into two sides sandwiching the partition member 44. Further, a pressure receiving chamber 78 in which a part of the wall portion is constituted by the main rubber elastic body 16 and is subjected to pressure fluctuation when vibration is input is formed on one side (upper in FIG. 1) sandwiching the partition member 44. In addition, on the other side (lower side in FIG. 1) across the partition member 44, a part of the wall portion is configured by the diaphragm 34, and an equilibrium chamber 80 in which volume change is easily allowed is formed. ing.

  In the state where the partition member 44 is assembled to the second mounting bracket 14, the pressure in the pressure receiving chamber 78 through the through hole 60 formed in the lid bracket 48 with respect to one surface of the movable rubber film 64. And the pressure in the equilibrium chamber 80 is applied to the other surface through a central hole 56 formed in the partition metal body 46. As a result, the movable rubber film 64 is elastically deformed based on the relative pressure difference between the pressure receiving chamber 78 and the equilibrium chamber 80, and is applied to the pressure receiving chamber 78 when medium to high frequency small amplitude vibration described later is input. The movable rubber film 64 constitutes a hydraulic pressure absorption mechanism that absorbs the pressure fluctuation that is caused to escape to the equilibrium chamber 80 side. Note that, under the non-input state of vibration, the short-circuit slit 72 formed in the movable rubber film 64 is held in a closed state by the elasticity of the movable rubber film 64 itself.

  Further, the tunnel-like flow path formed by covering the opening of the circumferential groove 52 with the lid fitting 48 is communicated with the pressure receiving chamber 78 through a communication hole (not shown) formed at one end of the lid fitting 48. At the same time, the other end is communicated with the equilibrium chamber 80 through a communication hole (not shown) formed in the partition metal fitting body 46. Thus, an orifice passage 82 that communicates the pressure receiving chamber 78 and the equilibrium chamber 80 with each other is formed by using the circumferential groove 52 formed in the partition member 44.

  In addition, the orifice passage 82 in the present embodiment is tuned so that the resonance frequency of the fluid that flows inside is in a low frequency range of about 10 Hz, and is low with respect to low frequency vibration corresponding to an engine shake of an automobile. The vibration isolation effect based on the flow action such as the resonance action of the fluid flowing through the orifice passage 82 is effectively exhibited. Such tuning of the orifice passage 82 can be set by appropriately adjusting the ratio of the passage length and the passage sectional area of the orifice passage 82.

  In the vehicle engine mount 10 having the structure according to the present embodiment, the first mounting bracket 12 is mounted on a power unit (not shown) and the second mounting bracket 14 is mounted on a vehicle body (not shown). To be fitted. When a vibration load is input between the first mounting bracket 12 and the second mounting bracket 14 in the vertical direction, which is the main vibration input direction, the intended vibration-proofing effect is based on the fluid flow action and the like. It has come to be demonstrated.

  That is, when a low-frequency large-amplitude vibration such as an engine shake is input between the first mounting bracket 12 and the second mounting bracket 14 when the automobile is running, the main rubber elastic body 16 is elastically deformed. Thus, pressure fluctuation is exerted in the pressure receiving chamber 78. Accordingly, the sealed fluid is caused to flow between the pressure receiving chamber 78 and the equilibrium chamber 80 through the orifice passage 82 tuned to a low frequency range corresponding to an engine shake or the like, and based on a fluid action such as a resonance action of the fluid. Anti-vibration effects such as a high damping effect are effectively exhibited. Note that when the vibration is input in the low frequency range, the amplitude of the input vibration is large, so that the hydraulic pressure absorption effect due to the minute elastic deformation of the movable rubber film 64 is not exhibited effectively. Therefore, a sufficient internal pressure fluctuation is exerted on the pressure receiving chamber 78, and fluid flow through the orifice passage 82 can be advantageously generated.

  On the other hand, when medium to high frequency small amplitude vibration such as idling vibration is input between the first mounting bracket 12 and the second mounting bracket 14 when the automobile is stopped, the pressure receiving chamber 78 and the equilibrium chamber 80 A relative pressure difference is generated between them, and the movable rubber film 64 is slightly deformed based on the pressure difference. Then, the hydraulic pressure in the pressure receiving chamber 78 is transmitted to the equilibrium chamber 80 side by the minute deformation of the movable rubber film 64. As a result, an anti-vibration effect such as a low dynamic spring effect based on the hydraulic pressure absorbing action due to minute elastic deformation of the movable rubber film 64 is effectively exhibited.

  In this embodiment, when the movable rubber film 64 is slightly deformed by inputting a normal vibration load to be subjected to vibration isolation, the short-circuit slit 72 formed in the movable rubber film 64 is closed. Is supposed to be retained.

  Furthermore, an impact vibration load is input between the first mounting bracket 12 and the second mounting bracket 14 due to, for example, overcoming a step during driving of the automobile, and the pressure in the pressure receiving chamber 78 is greatly reduced. As a result, the short-circuit slit 72 formed in the movable rubber film 64 is opened. That is, when the pressure receiving chamber 78 is greatly depressurized, the negative pressure in the pressure receiving chamber 78 is exerted on the movable rubber film 64, and the suction force toward the pressure receiving chamber 78 acts on the movable rubber film 64. With this suction force, the movable rubber film 64 is elastically deformed toward the pressure receiving chamber 78 and is displaced to the pressure receiving chamber 78 side. As a result, the short-circuit slit 72 is opened, and the pressure receiving chamber 78 and the equilibrium chamber 80 are communicated with each other through the short-circuit slit 72.

  As described above, when the pressure in the pressure receiving chamber 78 is greatly reduced and the movable rubber film 64 is elastically deformed toward the pressure receiving chamber 78 side, the short-circuit slit 72 formed in the movable rubber film 64 is opened. The pressure receiving chamber 78 and the equilibrium chamber 80 are communicated with each other through the short-circuit slit 72. Thereby, the fluid flow through the short-circuit slit 72 is generated between the pressure receiving chamber 78 and the equilibrium chamber 80, and the negative pressure in the pressure receiving chamber 78 is eliminated as quickly as possible. Therefore, it is possible to effectively prevent the generation of abnormal noise and vibration that are considered to be caused by the pressure drop in the pressure receiving chamber 78.

  As is clear from the above description, the shut-off state and the communication state of the short-circuit slit 72 can be switched according to the pressure acting on the pressure receiving chamber 78, and the elasticity of the movable rubber film 64 is utilized. The valve mechanism in the present embodiment is configured.

  Here, in the engine mount 10 having the structure according to the present embodiment, the crack prevention holes 76 are formed on both sides in the longitudinal direction of the short-circuit slit 72 formed in the movable rubber film 64, and the short-circuit slit 72 reaches the crack prevention hole 76. It is formed with a length. Accordingly, it is possible to prevent cracks from occurring at both ends in the longitudinal direction of the short-circuit slit 72 as the short-circuit slit 72 is opened and closed, and to improve the durability of the movable rubber film 64. In particular, in this embodiment, the crack prevention hole 76 is formed so as to penetrate the thickened reinforcing portion 74, and the occurrence of cracks near the end of the short-circuit slit 72 can be prevented more advantageously. ing.

  Moreover, in the present embodiment, the crack prevention hole 76 is covered and blocked by the lid protrusion 58 provided on the inner peripheral edge of the partition metal body 46 under the assembled state of the movable rubber film 64 to the partition member 44. ing. Thereby, the fluid is prevented from flowing between the pressure receiving chamber 78 and the equilibrium chamber 80 through the crack preventing hole 76, and the internal pressure fluctuation can be advantageously caused in the pressure receiving chamber 78 at the time of vibration input. Therefore, the fluid flow through the orifice passage 82 can be advantageously realized, and the intended vibration isolation effect can be effectively obtained.

  In particular, in the present embodiment, the crack prevention hole 76 is covered with a cover protrusion 58 that is overlapped from the equilibrium chamber 80 side. As a result, when a positive pressure fluctuation is exerted in the pressure receiving chamber 78, the opening of the crack preventing hole 76 on the equilibrium chamber 80 side is pushed against the lid protrusion 58 by the elastic deformation of the movable rubber film 64. By being applied, the blocking state of the crack prevention hole 76 is advantageously maintained. Therefore, when a positive pressure fluctuation is exerted on the pressure receiving chamber 78, the amount of fluid flow through the orifice passage 82 is advantageously ensured, and the vibration isolation effect based on the fluid flow action is effectively exhibited. It has become.

  Furthermore, by providing the lid protrusion 58 so as to come into contact with the reinforcing portions 74, 74 in the movable rubber film 64 from the equilibrium chamber 80 side, the movable rubber film 64 is supported from the equilibrium chamber 80 side, Elastic deformation of the movable rubber film 64 toward the equilibrium chamber 80 is limited. Accordingly, since the short-circuit slit 72 is advantageously held in the closed state, it is possible to advantageously prevent the positive pressure induced in the pressure receiving chamber 78 from being released to the equilibrium chamber 80 side through the short-circuit slit 72. The anti-vibration effect can be realized more advantageously.

  Furthermore, in the present embodiment, the support protrusion 62 formed on the inner peripheral edge of the lid fitting 48 is separated toward the pressure receiving chamber 78 side with respect to the central portion of the movable rubber film 64 relative to the annular support portion 66. It is positioned. Further, even when a negative pressure is applied to the pressure receiving chamber 78 by the input of the shocking vibration load and the movable rubber film 64 is elastically deformed so as to protrude toward the pressure receiving chamber 78 side, the support protrusion 62 is also provided. This prevents the protruding tip (end on the side of the equilibrium chamber 80) from contacting the movable rubber film 64. Thereby, the damage of the movable rubber film 64 due to the contact of the support protrusion 62 can be prevented, and the durability of the movable rubber film 64 can be advantageously improved.

  In this embodiment, the lid protrusion 58 is overlapped with the opening on the equilibrium chamber 80 side of the crack prevention hole 76, and the opening is covered with the cover protrusion 58, whereby the partition member of the movable rubber film 64 is obtained. The crack prevention hole 76 is closed under the assembled condition to 44. As described above, in the present embodiment, the movable rubber film 64 is assembled so as to be separable without being constrained with respect to the lid protrusion 58 at the formation site of the crack prevention hole 76. As a result, when a predetermined negative pressure is induced in the pressure receiving chamber 78 by the input of a shocking vibration load and the movable rubber film 64 is elastically deformed so as to protrude greatly toward the pressure receiving chamber 78 side, crack prevention is achieved. The contact state between the opening of the hole 76 on the equilibrium chamber 80 side and the lid protrusion 58 is released, and fluid flow between the pressure receiving chamber 78 and the equilibrium chamber 80 is generated through the crack prevention hole 76. ing. Therefore, the negative pressure in the pressure receiving chamber 78 is more quickly eliminated by the fluid flow through the short-circuit slit 72 and the fluid flow through the crack prevention hole 76, and the generation of abnormal noise and vibration due to cavitation is more advantageous. Can be prevented.

  As mentioned above, although one Embodiment of this invention was described, this is an illustration to the last, Comprising: This invention is not interpreted restrictively at all by the specific description in this Embodiment.

  For example, in the above-described embodiment, the crack prevention hole 76 is closed by overlapping the upper end surface of the lid protrusion 58 with the opening on the equilibrium chamber 80 side of the crack prevention hole 76. However, the crack prevention hole 76 does not necessarily have to be closed by the annular lid protrusion 58 as shown in the above embodiment. Specifically, for example, a pair of protrusions that protrude from the inner peripheral edge of the partition metal fitting body 46 toward the pressure receiving chamber 78 are provided so as to be opposed to each other in the radial direction, and the protrusions are formed on the movable rubber film 64. By inserting the crack prevention hole 76 from the equilibrium chamber 80 side, the crack prevention hole 76 can be closed. According to this, the anti-cracking hole 76 is stably held in the closed state, and the vibration-proof characteristic can be stabilized.

  Furthermore, in the embodiment, the lid protrusion 58 integrally formed with the partition member 44 is overlapped with the crack prevention hole 76 from the equilibrium chamber 80 side, whereby the crack prevention hole 76 is blocked. However, the crack prevention hole 76 does not necessarily have to be blocked by the lid protrusion 58 covering the opening on the equilibrium chamber 80 side. Specifically, for example, the crack prevention hole 76 may be blocked by closing the opening of the crack prevention hole 76 on the pressure receiving chamber 78 side, or the pressure receiving chamber 78 of the crack prevention hole 76 may be blocked. The crack prevention hole 76 may be blocked by closing both side openings on the side and the equilibrium chamber 80 side.

  In the above-described embodiment, the short-circuit slit 72 is formed as a cut extending linearly. However, the short-circuit slit does not necessarily extend linearly, and is, for example, a cut extending by bending or bending. May be. Furthermore, a plurality of short-circuit slits may be formed in the movable rubber film 64. For example, two or more short-circuit slits 72 extending linearly in one radial direction of the movable rubber film 64 are formed, and the plurality of short-circuit slits are formed. The slits 72 may be formed so as to extend in different radial directions, and may be provided in a cross shape or a radial shape.

  Furthermore, in the said embodiment, although the radial direction center part which removed the reinforcement parts 74 and 74 and the cyclic | annular support part 66 in the movable rubber film 64 is formed by substantially constant board thickness, for example, it goes to an inner peripheral side. The plate thickness of the movable rubber film may be changed in the radial direction or the circumferential direction, for example, the plate thickness dimension gradually increases.

  Moreover, in the said embodiment, although the engine mount 10 of the structure provided with the orifice channel | path 82 tuned to the low frequency range is shown, for example, the 1st tuned to the low frequency range corresponding to an engine shake etc. is shown. For fluid-filled vibration isolators of various known structures, such as a fluid-filled vibration isolator having a structure with an orifice passage and a second orifice passage tuned in the middle frequency range corresponding to vibration during idling, etc. The present invention is applicable.

  In the above embodiment, the present invention is applied to an automobile engine mount. However, the present invention can also be applied to a fluid-filled vibration isolator other than the engine mount, such as a subframe mount. . Needless to say, the present invention can also be applied to a fluid-filled vibration isolator used for other than automobiles.

  In addition, although not enumerated one by one, the present invention can be carried out in a mode to which various changes, modifications, improvements and the like are added 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 present invention.

It is a longitudinal cross-sectional view which shows the engine mount for motor vehicles as one Embodiment of this invention, Comprising: The II sectional view taken on the line in FIG. The bottom view which shows the movable rubber film which comprises the engine mount shown by FIG. III-III sectional view taken on the line of the movable rubber film shown in FIG. FIG. 4 is a sectional view of the movable rubber film shown in FIG. 2 taken along the line IV-IV.

Explanation of symbols

10: engine mount, 12: first mounting bracket, 14: second mounting bracket, 16 rubber elastic body, 34: diaphragm, 42: fluid sealing region, 44: partition member, 64: movable rubber film, 66: Annular support part, 72: Short-circuit slit, 74: Reinforcing part, 76: Crack prevention hole, 78: Pressure receiving chamber, 80: Equilibrium room, 82: Orifice passage

Claims (5)

The first mounting member is spaced apart from one opening side of the second mounting member having the cylindrical portion, and the first mounting member and the second mounting member are connected to each other by the main rubber elastic body. As a result, one opening of the second mounting member is closed by the main rubber elastic body, and the other opening of the second mounting member is closed by a flexible membrane, so that the main body A fluid chamber sealed from the outside and sealed with an incompressible fluid is formed between the rubber elastic body and the flexible membrane, and the fluid chamber is divided into two by the partition member supported by the second mounting member. A pressure receiving chamber having a part of the wall made of the main rubber elastic body is formed on one side of the partition member, and one wall portion is formed on the other side of the partition member. An equilibrium chamber is formed with the flexible film formed on the portion, and the pressure receiving chamber and the equilibrium chamber communicate with each other. In the fluid filled type vibration damping device office passage is formed,
A movable rubber film is assembled to the partition member, and the pressure of the pressure receiving chamber is exerted on one surface of the movable rubber film, and the pressure of the equilibrium chamber is exerted on the other surface. A hydraulic pressure absorption mechanism configured to absorb the pressure fluctuation of the pressure receiving chamber by elastic deformation of the movable rubber film based on the pressure difference of
A short-circuit slit extending at a predetermined length is formed through the movable rubber film at the center of the movable rubber film,
The short-circuit slit is held closed based on the elasticity of the movable rubber film, and a predetermined negative pressure is induced to the pressure receiving chamber at the time of vibration input so that the movable rubber film moves toward the pressure receiving chamber side. A valve mechanism that is in a communication state by being elastically deformed is configured.
At both ends of the short-circuit slit, a crack prevention hole is formed that penetrates the movable rubber film in the thickness direction, and the crack prevention hole is formed when the movable rubber film is assembled to the partition member. A fluid-filled vibration isolator characterized by being closed.   The reinforcement part made thicker than the other part in the both ends of the short-circuit slit is provided in the movable rubber film, and the crack prevention hole is formed so as to penetrate the reinforcement part. The fluid-filled vibration isolator described in 1.   3. The fluid filled type vibration damping device according to claim 1, wherein an opening of the crack prevention hole on the side of the equilibrium chamber is closed under a state in which the movable rubber film is assembled to the partition member. .   The fluid-filled vibration isolator according to any one of claims 1 to 3, wherein the short-circuit slit extends linearly through the center of the movable rubber film.   The outer peripheral edge of the movable rubber film is supported by the partition member, and the crack prevention hole is blocked by overlapping the partition member with the opening of the crack prevention hole formed in the movable rubber film. The fluid-filled vibration isolator according to any one of claims 1 to 4.

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