JP2008249075A - Fluid sealed type vibration damper - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a fluid sealed type vibration damper having a novel structure capable of reducing or avoiding the occurrence of noise and vibration which is a problem upon inputting a shocking vibration load while effectively realizing a target vibration damping effect based on flowing action of a fluid during normal vibration input. <P>SOLUTION: A movable rubber membrane 64 is assembled to a partitioning member 44. 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 the movable rubber membrane. A projection part 68 projecting toward the pressure receiving chamber 78 side is formed at a central part of the movable rubber membrane 64. A short-circuiting slot 72 is formed that penetrates the movable rubber membrane 64 at the portion where the projection part 68 is formed, and the short-circuiting slot 72 is held in a closed state based on elasticity of the movable rubber membrane 64. A valve mechanism that becomes communicated by the movable rubber membrane 64 being elastically deformed toward the pressure receiving chamber 78 side during input of vibration is composed of the projection part 68. <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 rubber film that divides the pressure receiving chamber and the equilibrium chamber is assembled to the partition member, and the hydraulic pressure absorption action due to minute deformation of the movable rubber film is utilized, so that the tuning frequency range of the orifice passage is higher than There has been proposed a structure capable of obtaining an effective anti-vibration effect against vibrations in a high frequency range.

  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 rubber 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. A slit formed in the rubber film is opened, and the pressure receiving chamber and the equilibrium chamber are short-circuited with each other through the slit, so that the negative pressure in the pressure receiving chamber is quickly eliminated.

  However, in such a fluid-filled vibration isolator shown in Patent Document 1, since the movable rubber film separating the pressure receiving chamber and the equilibrium chamber is provided with a slit, a negative pressure is exerted on the pressure receiving chamber. In addition to the case, when a positive pressure is applied to the pressure receiving chamber, the slit opens, and the pressure receiving chamber and the equilibrium chamber are short-circuited through the slit. Therefore, the relative pressure fluctuation between the pressure receiving chamber and the equilibrium chamber cannot sufficiently occur, and it is difficult to obtain a sufficient amount of fluid that can flow between the two chambers through the orifice passage. Therefore, there is a possibility that the intended vibration isolation effect cannot be obtained effectively.

  Further, for example, it may be possible to make the slit difficult to open by limiting the elastic deformation of the movable rubber film by making the movable rubber film thick. According to this, an effective anti-vibration effect can be realized, but on the other hand, even when a shocking vibration load is input and the pressure in the pressure receiving chamber is greatly reduced, the inside of the pressure receiving chamber obtained by opening the slit is also provided. The negative pressure elimination effect tends to be insufficient, and it may be difficult to solve the problem of abnormal noise and vibration caused by cavitation as described above.

Japanese Patent No. 2805305

  Here, the present invention has been made against the background of the above-mentioned circumstances, and the problem to be solved is that the intended vibration isolation effect based on the fluid flow action during normal vibration input is effective. An object of the present invention is to provide a fluid-filled vibration isolator having a novel structure capable of reducing or avoiding the generation of abnormal noise and vibration, which are problems when inputting shock vibration load. .

  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 protrusion projecting toward the pressure receiving chamber is formed at the central portion of the movable rubber film, and a short-circuit hole penetrating the movable rubber film is formed at a portion where the protrusion is formed. Further, the short-circuit hole is held in a closed state based on the elasticity of the movable rubber film, while a predetermined negative pressure is induced to the pressure receiving chamber at the time of vibration input, so that the movable rubber film is moved to the pressure receiving chamber side. Elastic deformation towards A valve mechanism which is communicated state by Rukoto, characterized in that it is constituted by the projecting portion.

  In such a fluid filled type vibration isolator having a structure according to the present invention, when the pressure in the pressure receiving chamber is greatly reduced by the input of shocking vibration load, the movable rubber film moves toward the pressure receiving chamber. Due to the elastic deformation, the short-circuit hole is opened based on the elasticity of the movable rubber film. As a result, a fluid flow is generated between the pressure receiving chamber and the equilibrium chamber through the short-circuit hole, and the negative pressure in the pressure receiving chamber is eliminated as quickly as possible. Therefore, it is possible to reduce or avoid abnormal noise and vibration that are considered to be caused by a pressure drop in the pressure receiving chamber.

  On the other hand, when a positive pressure is exerted on the pressure receiving chamber by the input of a shocking vibration load, the movable rubber film is elastically deformed toward the equilibrium chamber side, and the short-circuit hole is formed based on the elasticity of the movable rubber film. It is kept closed. Thus, fluid flow through the short-circuit hole between the pressure receiving chamber and the equilibrium chamber is prevented, and internal pressure fluctuations induced in the pressure receiving chamber are advantageously ensured without being released to the equilibrium chamber side. Therefore, the flow of fluid through the orifice passage can be advantageously produced, and the vibration isolation effect based on the fluid flow action can be effectively obtained.

  In addition, in the fluid-filled vibration isolator having a structure according to the present invention, the protrusion formed on the movable rubber film is protruded toward the pressure receiving chamber. Thereby, when a negative pressure is exerted in the pressure receiving chamber, the projecting portion is sucked and deformed toward the outer peripheral side of the movable rubber film, so that the short-circuit hole is opened more advantageously. On the other hand, when a positive pressure is exerted in the pressure receiving chamber, the projecting portion is pressed toward the inner peripheral side, whereby the short-circuit hole is more advantageously held in a closed state. As described above, since the protrusion is protruded into the pressure receiving chamber, the valve mechanism can be advantageously opened and closed according to the pressure fluctuation exerted in the pressure receiving chamber.

  Further, in the fluid filled type vibration damping device according to the present invention, the projecting portion of the movable rubber film is formed at a portion where the short-circuit hole is opened toward the equilibrium chamber, and is expanded toward the equilibrium chamber. It is desirable that an opening recess having an opening shape is formed.

  According to this, when the pressure in the pressure receiving chamber decreases due to the input of shocking vibration and the movable rubber film is sucked into the pressure receiving chamber and deformed, it is formed to expand toward the equilibrium chamber. By providing the opening recess, the short-circuit hole is advantageously opened. Therefore, when a negative pressure that causes bubbles due to cavitation is exerted on the pressure receiving chamber, fluid flow through the short-circuit hole is advantageously generated so that the negative pressure in the pressure receiving chamber is quickly eliminated. It has become.

  Further, in the fluid filled type vibration damping device according to the present invention, the protrusion has a protrusion shape extending linearly through a central portion of the movable rubber film, and the short-circuit hole is the protrusion. It may be a slit-shaped short-circuit slit extending along the line.

  By adopting such ridge-shaped protrusions and slit-shaped short-circuit holes, when negative pressure is applied to the pressure receiving chamber by the input of shocking vibration load, along with the deformation of the movable rubber film The portions located on both sides of the short-circuit slit in the protrusion are displaced away from each other, and the short-circuit slit is opened.On the other hand, when positive pressure is applied to the pressure receiving chamber, the short-circuit slit is Since the portions located on both sides of the sandwich are pressed against each other, the closed state of the short-circuit slit is more advantageously maintained. Therefore, it is possible to achieve both the intended vibration isolation performance and the reduction or avoidance of abnormal noise and vibration due to cavitation.

  In the fluid-filled vibration isolator according to the present invention, crack preventing holes penetrating the movable rubber film are formed at both end portions linearly extending in the short-circuit slit, and the movable rubber film It is also possible to adopt a structure in which the crack prevention hole is closed under the state of being assembled to the partition member.

  Thus, by forming a crack prevention hole in the longitudinal direction both ends of the short-circuit slit where a crack is likely to occur, the progress of the crack can be prevented and the durability of the movable rubber film can be advantageously improved. In addition, the crack prevention hole is closed when the movable rubber film is attached to the partition member, so that fluid can be passed between the pressure receiving chamber and the equilibrium chamber through the crack prevention hole when the vibration target vibration is input. By preventing the fluid from flowing, it is possible to advantageously secure the amount of fluid flow through the orifice passage and to effectively exhibit the vibration-proofing effect based on the fluid flow action.

  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 a non-mounted state of the engine mount 10 according to the present embodiment.

  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.

  In this way, the diaphragm 34 is assembled to the integrally vulcanized molded product of the main rubber elastic body 16 having the first mounting bracket 12 and the second mounting bracket 14, so that the axial direction of the second mounting bracket 14 is achieved. The upper opening is fluid-tightly closed with the main rubber elastic body 16, and the lower opening in the axial direction of the second mounting bracket 14 is fluid-tightly closed with a 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 support protrusion 58 is integrally formed with the partition metal fitting body 46 at the opening peripheral edge of the central hole 56. The support protrusion 58 has an annular shape extending in the circumferential direction, and protrudes upward from the inner peripheral edge of the bottom wall portion of the central recess 54. In addition, by providing the support protrusion 58 on the inner peripheral edge of the partition metal fitting body 46, the support protrusion 58 and the wall of the central recess 54 cooperate to extend over the entire circumference in the circumferential direction. 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. Further, a lid protrusion 62 is integrally formed on the opening peripheral edge of the through hole 60. The lid protrusion 62 has an annular shape extending over the entire circumference, and is formed so as to protrude downward from the inner peripheral edge portion 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.

  Here, the movable rubber film 64 is formed with a valve protrusion 68 as a protrusion. The valve protrusion 68 protrudes toward one side of the movable rubber film 64 in the plate thickness direction, and is formed so as to extend in one radial direction at a position separated from the annular support portion 66 toward the inner peripheral side. ing. Further, the valve protrusion 68 in the present embodiment has a protruding tip portion that is thinner than the base end portion.

  In addition, an opening recess 70 that opens to the surface opposite to the valve protrusion 68 is formed in a portion of the movable rubber film 64 where the valve protrusion 68 is formed. The opening recess 70 is linearly formed so as to extend in the longitudinal direction of the valve protrusion 68, and is opened at the lower end surface of the movable rubber film 64. Moreover, the opening recess 70 in this embodiment is formed so that it may expand gradually toward the downward direction which is the opening part side.

  Further, a short-circuit slit 72 as a short-circuit hole is formed at a portion where the valve protrusion 68 is formed in the movable rubber film 64. The short-circuit slit 72 is a notch that extends linearly in the longitudinal direction of the valve protrusion 68 and penetrates the movable rubber film 64 in the thickness direction, and is centered in the width direction (left and right in FIG. 2) of the valve protrusion 68. Is formed. Further, the short-circuit slit 72 is formed so as to open to the protruding tip portion of the valve protrusion 68 on one side in the plate thickness direction of the movable rubber film 64 and to open in the opening recess 70 on the other side in the plate thickness direction. Has been. Moreover, the valve protrusion 68 is divided | segmented into the width direction both sides by this short-circuit slit 72, and it is set as a pair of valve protrusion 68a, 68b. In a stationary state in which no vibration load is input between the first mounting bracket 12 and the second mounting bracket 14 under the assembled state of the movable rubber film 64 with respect to the partition bracket main body 46 and the lid bracket 48 described later. The pair of valve protrusions 68a and 68b are brought into contact with each other by the elasticity of the movable rubber film 64, so that the short-circuit slit 72 is held in a closed state.

  Furthermore, reinforcing portions 74 and 74 are formed on both longitudinal sides of the valve protrusions 68a and 68b. The reinforcing portion 74 has a substantially rectangular shape that is curved in the circumferential direction in plan view, and is thinner than the portions where the valve protrusions 68a and 68b are formed, while the valve protrusion at the central portion of the movable rubber film 64. It is thicker than the part which removed 68a, 68b. A crack prevention hole 76 is formed in the reinforcing portion 74 of the movable rubber film 64. The crack preventing hole 76 is a small-diameter circular hole formed through each of the movable rubber film 64 where the pair of reinforcing portions 74 and 74 are formed, and is formed on both longitudinal sides of the valve protrusions 68a and 68b. . Furthermore, in the present embodiment, the short-circuit slit 72 is formed so as to extend slightly on both sides of the longitudinal ends of the valve protrusions 68a and 68b, and the short-circuit slit 72 is formed with a length reaching the crack prevention hole 76. Has been.

  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. The annular support portion 66 is sandwiched between the partition wall body 46 and the lid member 48 that is overlapped with the partition member body 46 from above while being positioned and supported between the peripheral wall portion 54 and the radial direction of the support protrusion 58. As a result, 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. In particular, in the present embodiment, the protruding front end surface of the cover protrusion 62 provided on the inner peripheral edge of the cover metal 48 is overlapped with the crack prevention hole 76 from above, so that the partition metal body of the movable rubber film 64 is provided. The crack prevention hole 76 is closed under the assembled state to the 46 and the lid fitting 48.

  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 fitting 46 so that the diaphragm 34 and the partition member 44 are relatively positioned.

  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 is assembled fluid-tightly 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 present embodiment, the partition member 44 is assembled to the second mounting bracket 14 via the seal rubber layer 32, and the space between the second mounting bracket 14 and the partition member 44 is sealed in a fluid-tight manner.

  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. Further, the valve protrusions 68a and 68b formed on the movable rubber film 64 are projected to the pressure receiving chamber 78 side in the assembled state of the partition member 44 to the second mounting bracket 14 and the movable rubber film. An opening recess 70 formed in 64 is opened toward the equilibrium chamber 80 side.

  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. As is clear from the above description, the movable rubber film 64 constitutes the hydraulic pressure absorbing mechanism in the present embodiment.

  In the present embodiment, when the movable rubber film 64 is slightly deformed by inputting a normal vibration load to be subjected to vibration isolation, the contact between the valve protrusions 68a and 68b is maintained. Thus, the short-circuit slit 72 formed in the movable rubber film 64 is held in a closed state.

  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. Then, as shown in FIG. 5, 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.

  Here, the valve protrusions 68a and 68b formed integrally with the movable rubber film 64 are protruded toward the pressure receiving chamber 78, so that the movable rubber film 64 is also shown in FIG. The valve protrusions 68a and 68b are displaced so as to be separated from each other as they are elastically deformed so as to protrude toward the pressure receiving chamber 78 side. Then, the pair of valve protrusions 68 a and 68 b are displaced so as to be separated from each other, whereby 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.

  In particular, the movable rubber film 64 in the present embodiment is formed with an opening recess 70 that gradually expands toward the equilibrium chamber 80 side, and a short-circuit slit 72 is formed so as to open into the opening recess 70. Yes. Therefore, the short-circuit slit 72 is easily opened by elastic deformation of the movable rubber film 64 due to the negative pressure in the pressure receiving chamber 78.

  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.

  In addition, in the present embodiment, the valve protrusion 68 is provided so as to protrude into the pressure receiving chamber 78, and the short-circuit slit 72 is formed so as to penetrate the movable rubber film 64 at a portion where the valve protrusion 68 is formed. Yes. As a result, when the pressure in the pressure receiving chamber 78 is reduced, the negative pressure in the pressure receiving chamber 78 is applied to the valve protrusion 68, thereby pulling the valve protrusion 68 toward both sides in the width direction. Power is exerted. Then, due to the elasticity of the movable rubber film 64 and the action of the pressure in the pressure receiving chamber 78, the pair of valve protrusions 68a and 68b are separated more advantageously, and the short-circuit slit 72 is sufficiently opened. .

  On the other hand, when the pressure in the pressure receiving chamber 78 rises due to the input of a shocking vibration load, as shown in FIG. 6, the short-circuit slit 72 formed in the movable rubber film 64 is maintained in the cut-off state. It has come to be. That is, when the pressure in the pressure receiving chamber 78 is significantly increased, the positive pressure in the pressure receiving chamber 78 is exerted on the movable rubber film 64, and the pressing force toward the equilibrium chamber 80 acts on the movable rubber film 64. To do. The movable rubber film 64 is elastically deformed by the pressing force, and the central portion is displaced toward the equilibrium chamber 80 side.

  Here, when the movable rubber film 64 is elastically deformed so as to protrude toward the equilibrium chamber 80, the valve protrusions 68a and 68b formed integrally with the movable rubber film 64 are protruded toward the pressure receiving chamber 78. Accordingly, as shown in FIG. 6, the projecting tip portions of the valve protrusions 68a and 68b are pressed against each other, and the short-circuit slit 72 is maintained in the closed state. As a result, when a positive pressure is applied to the pressure receiving chamber 78, the hydraulic pressure in the pressure receiving chamber 78 is prevented from being released to the equilibrium chamber 80 side by the fluid flow through the short-circuit slit 72, and the pressure through the orifice passage 82. The amount of fluid flow is advantageously ensured, and the vibration isolation effect based on the fluid flow action is effectively exhibited.

  In addition, in the present embodiment, the valve protrusion 68 is provided so as to protrude into the pressure receiving chamber 78, and the short-circuit slit 72 is formed so as to penetrate the movable rubber film 64 at a portion where the valve protrusion 68 is formed. Yes. Thus, when the pressure in the pressure receiving chamber 78 is increased, the positive pressure in the pressure receiving chamber 78 is applied to the valve protrusion 68, thereby pressing the valve protrusion 68 toward the center in the width direction. A compressive force is exerted. Then, the elasticity of the movable rubber film 64 and the pressure in the pressure receiving chamber 78 cause the pair of valve protrusions 68a and 68b to adhere more advantageously so that the short-circuit slit 72 is stably held in the closed state. It has become.

  As is clear from the above description, the contact state and separation of the valve protrusions 68a and 68b are switched according to the pressure acting on the pressure receiving chamber 78, so that the blocking state and the communication state of the short-circuit slit 72 are switched. Thus, the valve mechanism in the present embodiment is constituted by the valve protrusions 68a and 68b.

  As described above, in the engine mount 10 according to the present embodiment, when an impact vibration load is input, it is possible to reduce or avoid abnormal noise and vibration caused by cavitation, and excellent vibration isolation based on fluid flow action. The effect can be realized at a high level in a balanced manner. In addition, valve protrusions 68a and 68b having a specific shape protruding into the pressure receiving chamber 78 are formed integrally with the movable rubber film 64, and the pressure receiving chamber 78 and the equilibrium chamber 80 are communicated between the overlapping surfaces of the valve protrusions 68a and 68b. By providing the short-circuit slit 72, when a positive pressure is exerted on the pressure receiving chamber 78, the valve protrusions 68 a and 68 b are pressed against each other using the elasticity of the movable rubber film 64 itself and the pressure in the pressure receiving chamber 78. At least, the opening of the short-circuit slit 72 can be prevented. Therefore, the above-described excellent effects can be realized with a simple structure and a small number of parts without providing a special member such as a restraining member in order to limit the elastic deformation of the movable rubber film 64.

  Further, 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 length of the short-circuit slit 72 reaching the crack prevention hole 76 is long. Is formed. 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 this embodiment, the crack prevention hole 76 is covered and blocked by the lid protrusion 62 provided at the inner peripheral edge of the lid metal 48 under the assembled state of the movable rubber film 64 to the partition member 44. Yes. 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.

  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 embodiment, the valve protrusion 68 extending in the radial direction is formed as a protrusion provided on the movable rubber film 64, and the short-circuit slit 72 extending in the longitudinal direction of the valve protrusion 68 is formed as a short-circuit hole. However, the shape and the like of the protrusion and the short-circuit hole are not limitedly interpreted by the specific shape described in the embodiment. Specifically, for example, the protrusion may have a cross shape extending in a radial direction perpendicular to each other, and a cross slit-like short-circuit hole may be formed so as to extend in the center in the width direction of the protrusion. Further, for example, the protrusion may be a mountain-shaped protrusion protruding at the center of the movable rubber film 64 in the radial direction, and the short-circuit hole may be a needle hole-shaped small-diameter hole penetrating the center of the protrusion. . Moreover, in the said embodiment, although the valve protrusion 68 and the short circuit slit 72 are extended linearly, you may make it the slit shape which a protrusion part and a short circuit hole extend, for example by curving or bending.

  Further, in the embodiment, the radial intermediate portion of the movable rubber film 64 that is out of the valve protrusion 68, the opening recess 70, and the annular support portion 66 is formed with a substantially constant plate thickness. The plate thickness may be changed in the radial direction or the circumferential direction, for example, the plate thickness dimension gradually increases toward the circumferential side.

  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. The fluid-filled vibration isolator having various known structures, such as a fluid-filled vibration-proof device having a structure including the orifice passage 82 and a second orifice passage 82 tuned to an intermediate frequency range corresponding to vibration during idling, etc. On the other hand, 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 top 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. The longitudinal cross-sectional view which shows the state in which the negative pressure was exerted on the receiving pressure chamber in the engine mount shown by FIG. The longitudinal cross-sectional view which shows the state in which the positive pressure was exerted on the receiving pressure chamber in the engine mount shown by FIG.

Explanation of symbols

10: engine mount, 12: first mounting bracket, 14: second mounting bracket, 16 main rubber elastic body, 34: diaphragm, 42: fluid sealing region, 44: partition member, 64: movable rubber film, 68: Valve ridge, 70: Opening recess, 72: Short-circuit slit, 76: Crack prevention hole, 78: Pressure receiving chamber, 80: Equilibrium chamber, 82: Orifice passage

Claims (4)

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 equilibration chamber is formed by the flexible membrane, and the pressure receiving chamber and the equilibration 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 absorbing 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 protrusion projecting toward the pressure-receiving chamber is formed in the central portion of the movable rubber film, and a short-circuit hole penetrating the movable rubber film is formed in the formation portion of the protrusion,
Further, the short-circuit hole is held closed based on the elasticity of the movable rubber film, while a predetermined negative pressure is induced to the pressure receiving chamber at the time of vibration input so that the movable rubber film is moved to the pressure receiving chamber side. A fluid-filled vibration damping device, characterized in that a valve mechanism that is brought into a communication state by being elastically deformed toward the surface is constituted by the protrusions.   2. An opening recess having a shape that expands toward the equilibrium chamber is formed in an opening portion of the short-circuit hole toward the equilibrium chamber at a portion where the protrusion is formed in the movable rubber film. The fluid-filled vibration isolator described in 1.   The projecting portion has a ridge shape that linearly extends through a central portion of the movable rubber film, and the short-circuit hole is a slit-shaped short-circuit slit extending along the projecting portion. The fluid-filled vibration isolator according to 1 or 2.   At both end portions that extend linearly in the short-circuit slit, a crack prevention hole that penetrates the movable rubber film is formed, and the crack prevention hole is in an assembled state of the movable rubber film to the partition member. The fluid-filled vibration isolator according to claim 3, wherein is closed.

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