JP4820792B2 - Fluid filled vibration isolator - Google Patents

Description

  The present invention relates to a fluid-filled vibration isolator that obtains a vibration isolation effect based on the flow action of an incompressible fluid enclosed in an internal fluid chamber, and in particular, a hydraulic pressure that absorbs pressure fluctuations in the fluid chamber. The present invention relates to a fluid-filled vibration isolator having an absorption mechanism.

  Conventionally, as a type of vibration isolator such as an anti-vibration coupling body and an anti-vibration support body interposed between members constituting a vibration transmission system, an anti-vibration effect is obtained based on the flow action of an incompressible fluid. There has been known a fluid-filled vibration isolator. In this fluid-filled vibration isolator, the first mounting member and the second mounting member are connected by the main rubber elastic body, and a part of the wall portion is configured by the main rubber elastic body to enclose the incompressible fluid. The pressure receiving chamber is formed with an equilibrium chamber in which a part of the wall portion is made of a flexible membrane that is easily deformed and in which an incompressible fluid is sealed, and the two chambers communicate with each other through an orifice passage. It is said that. According to such a structure, a relative pressure fluctuation occurs between the pressure receiving chamber and the equilibrium chamber due to the vibration input, and the vibration isolation effect is based on the fluid action such as the resonance action of the fluid that flows through the orifice passage. An orifice effect is obtained. Such a fluid-filled vibration isolator has been studied for application to, for example, an automobile engine mount, body mount, and differential mount as well as a suspension member mount.

  Furthermore, as a development type of the above-described fluid-filled vibration isolator, there is a fluid-filled vibration isolator equipped with a hydraulic pressure absorbing mechanism. In this hydraulic pressure absorbing mechanism, a movable rubber film is disposed between the pressure receiving chamber and the equilibrium chamber so that 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. The structure is such that the pressure fluctuation in the pressure receiving chamber is absorbed by deformation of the movable rubber film due to the relative pressure difference between the pressure receiving chamber and the equilibrium chamber. As a result, for example, when a problem vibration is input in a frequency range higher than the tuning frequency of the orifice passage, the pressure fluctuation in the pressure receiving chamber is absorbed by the elastic deformation of the movable rubber film, thereby avoiding a high dynamic spring. Therefore, stabilization of the vibration isolation effect is achieved.

  By the way, in the above-described fluid-filled vibration isolator, when a large vibration load is applied between the first mounting member and the second mounting member, an excessive negative pressure is generated in the pressure receiving chamber. In some cases, air dissolved in the fluid is separated to generate bubbles called cavitation or the like. When the water hammer pressure is generated along with the collapse of the bubbles and propagates to the first mounting member or the second mounting member, the water hammer pressure is transmitted to the vibration-proof target member such as the body of the automobile, which causes a problem. There was a risk of sound and vibration.

  In order to deal with such a problem, for example, Patent Document 1 (Japanese Patent Laid-Open No. 2007-107712) proposes a structure in which a relief mechanism is provided by using a part of an orifice passage. That is, a short-circuit channel is formed in the partition member using a part of the orifice passage, and a relief valve is provided in the opening on the pressure receiving chamber side of the short-circuit channel. At the time of shocking vibration input, the relief valve is opened by the action of the negative pressure of the pressure receiving chamber, and the pressure receiving chamber and the equilibrium chamber are short-circuited through the short-circuit channel. As a result, the pressure in the pressure receiving chamber and the pressure in the equilibrium chamber are brought into an equilibrium state, and the pressure in the pressure receiving chamber is prevented from reaching a negative pressure that generates cavitation. Is prevented.

  However, in the fluid-filled vibration isolator described in Patent Document 1, the relief valve is provided separately from the partition member, the movable rubber film, and the like, so that the number of parts increases and the molding process and assembly process of the relief valve are performed. There has been a problem that the manufacturing cost is increased due to an increase in the manufacturing process. In addition, since the short-circuit flow path is formed by using a part of the orifice passage, the degree of freedom in designing the orifice passage is limited, or a part of the wall of the orifice passage is constituted by a relief valve. There is a possibility that the fluid flow action through the orifice passage may not be stably generated.

  In order to deal with such a problem, for example, as shown in Patent Document 2 (Japanese Patent Laid-Open No. 61-294236), a cut or the like is made in the movable rubber film so that the pressure receiving chamber is in a negative pressure state. It is conceivable that a slit is developed based on the opening of the cut portion due to the deformation of the movable rubber film, and the pressure receiving chamber and the equilibrium chamber are short-circuited through the slit. That is, since the relief mechanism of the pressure receiving chamber is configured using elastic deformation of the movable rubber film, it is not necessary to provide a relief valve separately, and the number of parts and the manufacturing process can be reduced.

  However, in the fluid-filled vibration isolator according to Patent Document 2, when the movable rubber film is provided with a cut, an excessive positive pressure or the like that does not require opening the cut portion is generated in the pressure receiving chamber. However, there is a possibility that the movable rubber film is elastically deformed and the cut portion is opened. For this reason, the pressure receiving chamber and the equilibrium chamber are short-circuited even when vibration is input in the tuning frequency range of the orifice passage to be vibrated, making it difficult to secure a sufficient amount of fluid flow through the orifice passage. However, there were problems that were difficult to obtain stably. In addition, since the movable rubber film is repeatedly elastically deformed, the crack at the end of the cut portion may be extended, and the durability of the movable rubber film may easily become a problem.

JP 2007-107712 A JP-A 61-294236

  Here, the present invention has been made in the background as described above, and the problem to be solved is that the number of parts of the relief mechanism of the pressure receiving chamber and the manufacturing process are reduced, thereby reducing the cost. In addition to being shown, it is an object of the present invention to provide a fluid-filled vibration isolator having a novel structure that can stably obtain a vibration isolating effect based on a fluid flow action through an orifice passage.

  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, the present invention is characterized in that the first mounting member and the second mounting member are connected by the main rubber elastic body, and a part of the wall portion is configured by the main rubber elastic body so that the incompressible fluid is formed. And a pressure-receiving chamber in which a part of the wall portion is formed by a flexible membrane to form an incompressible fluid, and the pressure-receiving chamber and the equilibrium chamber communicate with each other by an orifice passage. In addition, a movable rubber film is disposed between the pressure receiving chamber and the equilibrium chamber so that the pressure of the pressure receiving chamber is exerted on one surface of the movable rubber film and the equilibrium chamber is disposed on the other surface of the movable rubber film. In a fluid-filled vibration isolator configured with a hydraulic pressure absorption mechanism that absorbs minute pressure fluctuations in the pressure receiving chamber by applying pressure, a relief hole is formed through the movable rubber film, and the relief hole Projecting on one side of the movable rubber film around The pressure-receiving chamber side cylindrical protrusion is integrally formed on the movable rubber film, while the pressure-receiving chamber side contact member is disposed on one surface side of the movable rubber film at the relief hole forming portion and the other of the movable rubber film An equilibrium chamber side abutting member is disposed on the surface of the pressure chamber, and the projecting tip surface of the pressure receiving chamber side cylindrical projection constituting one opening of the relief hole is brought into contact with the pressure receiving chamber side abutting member, The inside of the pressure-receiving chamber side cylindrical protrusion is communicated with the pressure-receiving chamber through a communication hole formed in the pressure-receiving chamber side abutting member, while the other opening peripheral edge of the relief hole is fully connected to the equilibrium chamber-side abutting member. In the fluid-filled vibration isolator, the relief holes are closed in close contact with each other around the circumference and closed by the equilibrium chamber side contact member.

  In such a fluid-filled vibration isolator having a structure according to the present invention, when a shock load is input and a negative pressure is generated in the pressure receiving chamber, the movable rubber film is elastically deformed toward the pressure receiving chamber. . Along with this deformation, the pressure receiving chamber side cylindrical protrusion integrally formed with the movable rubber film is compressed and deformed in the axial direction between the pressure receiving chamber side contact member and the movable rubber film, and the pressure receiving chamber side cylindrical protrusion. The other opening peripheral edge of the relief hole on the opposite side is displaced toward the pressure receiving chamber side by an amount corresponding to the amount of compressive deformation of the pressure receiving chamber side tubular member. Accordingly, the other opening peripheral edge of the relief hole is separated from the equilibrium chamber side contact member, and the pressure receiving chamber and the equilibrium chamber are short-circuited through the communication hole and the relief hole. The pressure is brought into an equilibrium state, and a relief effect is obtained in which the excessive negative pressure state of the pressure receiving chamber is eliminated. As a result, the pressure in the pressure receiving chamber is prevented from reaching a negative pressure that causes cavitation, and abnormal noise and vibration due to cavitation are prevented.

  In particular, in this structure, the relief mechanism that eliminates the over-negative pressure state of the pressure receiving chamber is configured to include a relief hole formed in the movable rubber film and a pressure-receiving chamber side cylindrical projection, and the pressure receiving chamber is negative pressure. The relief effect is exhibited by utilizing the deformation of the movable rubber film and the pressure-receiving chamber side cylindrical protrusion when the pressure is reduced. Accordingly, since the relief mechanism and the hydraulic pressure absorption mechanism using the movable rubber film are integrally provided, the vibration isolator equipped with both mechanisms can be realized with a small number of parts and the manufacturing process can be shortened. Thus, the manufacturing cost can be effectively reduced.

  In addition, since the relief mechanism is provided on the movable rubber film side, the degree of freedom in designing the orifice passage is effectively ensured, and the amount of fluid flow through the orifice passage is sufficiently secured. That is, since the resonance frequency of the movable rubber film is generally set in a high frequency range as compared with the resonance frequency of the fluid that flows through the orifice passage, the movable rubber membrane can be used at the time of vibration input in the tuning frequency range of the orifice passage. The film is difficult to deform. As a result, deformation of the pressure-receiving chamber side cylindrical projection due to deformation of the movable rubber film is also suppressed, and the contact state between the other opening peripheral edge of the relief hole and the equilibrium chamber side contact member is maintained well. The Therefore, when the vibration in the tuning frequency range of the orifice passage is input, the pressure in the pressure receiving chamber is prevented from leaking through the relief hole, and the fluid flow rate through the orifice passage is sufficiently secured. Is obtained.

  Further, in the fluid filled type vibration damping device according to the present invention, the pressure receiving chamber side cylindrical projecting portion of the pressure receiving chamber side contacting member opens directly into the pressure receiving chamber side cylindrical projecting portion to receive the pressure. A communication hole that allows the inside of the chamber-side cylindrical projection to communicate with the pressure receiving chamber may be formed. According to such a structure, since the communication hole formed in the pressure receiving chamber side contact member and the relief hole in the pressure receiving chamber side cylindrical projection are directly connected, the pressure receiving chamber and the equilibrium chamber are connected. It is possible to shorten the length of the channel that causes the short circuit and to improve the relief effect associated therewith.

  In the fluid filled type vibration isolator according to the present invention, a structure in which one relief hole in the movable rubber film is formed at the center of the movable rubber film may be employed. According to such a structure, positioning of the relief hole in the circumferential direction with respect to the pressure receiving chamber side contact member and the equilibrium chamber side contact member becomes unnecessary, and the assembly of the movable rubber film is further facilitated.

  In the fluid-filled vibration isolator according to the present invention, the protruding tip end surface of the pressure-receiving chamber side cylindrical protrusion is in contact with the pressure-receiving chamber side contact member over the entire circumference. , May be adopted. According to such a structure, the contact state between the pressure-receiving chamber side cylindrical protrusion and the pressure-receiving chamber side contact member is stable, and the relief hole is formed on the basis of stable compressive deformation in the axial direction of the cylindrical protrusion. The separated state of the other opening and the equilibrium chamber side contact member is stabilized. As a result, the pressure receiving chamber and the equilibrium chamber can be short-circuited reliably, and the relief effect can be more effectively exhibited.

  Further, in the fluid filled type vibration damping device according to the present invention, the movable rubber film is compressed in the thickness direction between the pressure receiving chamber side contact member and the equilibrium chamber side contact member around the relief hole. The disposed structure may be adopted. According to such a structure, the relief of the movable rubber film is caused by the displacement or deformation of the movable rubber film when the pressure of the pressure receiving chamber and the equilibrium chamber is applied to each one surface of the movable rubber film at the time of vibration input. The periphery of the hole is prevented from coming into contact with or separated from the contact members on the pressure-receiving chamber side and the equilibrium chamber side, and the generation of hitting sound due to such contact or separation is prevented. Even when a load of a normal size is inputted, the other opening peripheral edge of the relief hole is separated from the equilibrium chamber side abutting member as the pressure receiving chamber side cylindrical projection is compressed and deformed in the axial direction. This prevents the pressure receiving chamber from being unnecessarily short-circuited.

  Further, in the fluid filled type vibration damping device according to the present invention, the balance chamber side cylindrical protrusion protruding on the other surface of the movable rubber film around the relief hole is integrally formed on the movable rubber film, and also for relief. A structure in which the protruding front end surface of the equilibrium chamber side cylindrical projection constituting the other opening of the hole is in contact with the equilibrium chamber side contact member may be employed. According to such a structure, the spring characteristics of the cylindrical protrusions on the pressure receiving chamber side and the equilibrium chamber side cooperate, and the pressure receiving chamber side contact member and the equilibrium chamber side contact member in the thickness direction of the movable rubber film It is possible to set a large amount of pre-compression between the two. As a result, it is possible to secure a high degree of fluid tightness between the contact surface between the opening peripheral edge of the relief hole and the pressure receiving chamber side or the equilibrium chamber side contact member, and when a load of a normal size is input. The reliability of the closed state of the relief hole in the case of the above or the like is improved.

  Further, in the fluid filled type vibration damping device according to the present invention, the thick annular holding support portion is integrally formed at the outer peripheral edge portion of the movable rubber film, and the support member fixed to the second mounting member is used. A structure in which the pinching support portion is pinched and supported in a compressed state so that minute pressure fluctuations in the pressure receiving chamber are absorbed based on elastic deformation of the movable rubber film on the inner peripheral side of the pinching support portion. , May be adopted. According to such a structure, the outer peripheral edge of the movable rubber film is supported by the pinching support part in a compressed state, so that a gap allowing fluid flow is generated around the outer peripheral edge of the movable rubber film. It is not possible to. Thereby, pressure leakage through the gap in the pressure receiving chamber is suppressed, and the orifice effect can be obtained more stably.

  Further, in the fluid filled type vibration damping device according to the present invention, the displacement amount limiting members are arranged opposite to each other at predetermined distances on both sides in the thickness direction of the movable rubber film, and these displacement amount limiting members of the movable rubber film are disposed. A structure may be employed in which the amount of displacement of the movable rubber film on both sides in the thickness direction is limited by the contact with. According to such a structure, since the amount of displacement of the movable rubber film is limited by changing the distance between the movable rubber film and the displacement amount limiting member, the hydraulic pressure absorption effect based on the displacement of the movable rubber film There are easy tuning changes.

  In addition, the displacement amount limiting member according to this structure may be configured by a member different from the pressure receiving chamber side contact member and the equilibrium chamber side contact member described above, or the pressure receiving chamber side contact member and the equilibrium chamber. You may comprise with a side contact member. By adopting the latter in particular, the number of parts can be reduced. In addition, the displacement of the movable rubber film is, for example, that the pressure-receiving chamber side cylindrical protrusion is elastically deformed in the axial direction between the pressure-receiving chamber side contact member and the movable rubber film, and the pressure-receiving chamber-side cylindrical protrusion in the movable rubber film. A portion other than the other member is disposed in a free state with respect to the other member, and is displaced based on a pressure difference between the pressure receiving chamber and the equilibrium chamber between the pressure receiving chamber side contact member and the equilibrium chamber side contact member. Alternatively, when the movable rubber film is displaced, for example, the pressure-receiving-chamber-side cylindrical protrusion is elastically deformed in the axial direction between the pressure-receiving-chamber-side contact member and the movable rubber film, and the pressure-receiving chamber-side cylindrical protrusion is moved in the movable rubber film. Includes a part that is a predetermined distance away from the part and is fixed to another member, and the part between the fixed part and the pressure-receiving chamber side cylindrical projection is displaced by deformation due to the pressure difference between the pressure-receiving chamber and the equilibrium chamber. It is.

  Hereinafter, in order to clarify the present invention more specifically, embodiments of the present invention will be described. First, FIG. 1 shows an automobile engine mount 10 as an embodiment according to the fluid filled type vibration damping device of the present invention. The automobile 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 mounted on the power unit side and the second mounting bracket 14 is mounted on the vehicle body side, so that the power unit is supported in an anti-vibration manner with respect to the vehicle body.

  1 shows the state of the engine mount 10 as a single unit before being mounted on the automobile, but in the present embodiment, in the mounted state, the shared support load of the power unit is in the mount axis direction (in FIG. 1, (Up and down). Therefore, in the mounted state, the first mounting member 12 and the second mounting member 14 are displaced in the axial direction toward each other based on the elastic deformation of the main rubber elastic body 16. In addition, under such a mounted state, main vibrations to be vibrated are input substantially in the mount axis direction. In the following description, unless otherwise specified, the vertical direction refers to the vertical direction in FIG.

  More specifically, the first mounting member 12 has a small-diameter substantially cylindrical shape or a truncated cone shape, and a screw hole 18 that opens to the upper end surface is provided at the center portion thereof. The first mounting bracket 12 is screwed and fixed to a power unit side mounting member (not shown) through a screw hole 18.

  On the other hand, the second mounting bracket 14 has a large-diameter substantially cylindrical shape, and an inner flange-shaped step portion 20 is formed at an axially intermediate portion thereof, and from the inner peripheral edge portion of the step portion 20. A tapered portion 22 having a diameter that gradually decreases from the upper side to the lower side is formed at the upward portion. The second mounting bracket 14 is fixed to a mounting member on the vehicle body side via a bracket member (not shown).

  The first mounting bracket 12 is spaced apart from the opening of the second mounting bracket 14 having the tapered portion 22 so that the central axes of both the brackets 12 and 14 are positioned substantially on the same line. Yes. A main rubber elastic body 16 is disposed between the first mounting bracket 12 and the second mounting bracket 14.

  The main rubber elastic body 16 has a substantially frustoconical shape, and a large-diameter recess 24 having an inverted mortar shape or a hemispherical shape that opens downward is provided on an end surface on the large-diameter side. The small-diameter side end face of the main rubber elastic body 16 is vulcanized and bonded in a state where substantially the entire portion from the axially intermediate portion to the lower end portion of the first mounting member 12 is embedded. The inner peripheral surface of the tapered portion 22 of the second mounting bracket 14 is vulcanized and bonded to the outer peripheral surface of the large-diameter side end portion of the main rubber elastic body 16 over substantially the entire surface. Further, a thin seal rubber layer 26 integrally formed with the main rubber elastic body 16 is formed so as to cover substantially the entire inner peripheral surface from the step portion 20 to the lower end portion of the second mounting bracket 14. In other words, the main rubber elastic body 16 is formed as an integrally vulcanized molded product including the first mounting bracket 12 and the second mounting bracket 14, whereby the first mounting bracket 12 and the second mounting bracket 12 are attached. The metal fittings 14 are elastically connected to each other by the main rubber elastic body 16, and the opening above the second mounting metal fitting 14 is fluid-tightly closed by the main rubber elastic body 16.

  A diaphragm 28 as a flexible film is provided in the opening below the second mounting bracket 14. The diaphragm 28 is made of a thin rubber film that can be easily deformed, and has a substantially disk shape that is slackened in the axial direction. A large-diameter cylindrical fixing ring 30 is vulcanized and bonded to the outer peripheral edge of the diaphragm 28, and the fixing ring 30 is fitted into the opening below the second mounting bracket 14, so that the second mounting Since the metal fitting 14 is subjected to diameter reduction processing such as an eight-way drawing, the fixing ring 30 is fitted and fixed to the second mounting metal fitting 14 via a seal rubber layer 26 that is compressed and deformed in the radial direction.

  As a result, the diaphragm 28 is fixed to the second mounting bracket 14, the lower opening of the second mounting bracket 14 is fluid-tightly covered with the diaphragm 28, and at the inside of the second mounting bracket 14. Between the main rubber elastic body 16 and the diaphragm 28 facing each other in the axial direction, a fluid sealing region 32 sealed with respect to the external space is formed.

  In the fluid sealing region 32, a partition member 34 as a support member fixed to the second mounting bracket 14 is disposed. 2 to 4, the partition member 34 has a circular block shape as a whole, and is formed using a hard material such as a metal material or a synthetic resin material. The partition member 34 includes a partition member main body 36 and a lid member 38.

  The partition member main body 36 has a circular block shape. An upper recess 40 that opens to the upper end surface and a lower recess 42 that opens to the lower end surface from the axially intermediate portion of the partition member main body 36 are formed in the central portion in the radial direction of the partition member main body 36, respectively. Each of these recesses 40, 42 extends in the axial direction with a substantially constant circular cross section, and the diameter dimension of the lower recess 42 is larger than the diameter dimension of the upper recess 40. Moreover, the bottom wall part of both the recesses 40 and 42 cooperates with the axial direction intermediate part of the partition member main body 36, and the circular bottom part 44 of a thin disk shape is comprised. A through hole 46 is provided around the central portion in the radial direction of the circular bottom 44.

  The through-hole 46 according to the present embodiment includes a substantially fan-shaped first small hole 48 and a second small hole 50 whose width dimension gradually increases from the radially inner side to the outer side. The first small hole 48 and the second small hole 50 are different from each other in the ratio of the width dimension in the circumferential direction to the width dimension in the radial direction. A plurality are provided at equal intervals in the direction. In other words, the through-hole 46 is formed so as to penetrate in the thickness direction (up and down in FIGS. 1 and 3) in the radial intermediate portion and the outer peripheral portion of the circular bottom portion 44, and not to be formed in the radial central portion of the circular bottom portion 44. It has become.

  Further, a circumferential groove 52 extending in a spiral shape in the circumferential direction is formed on the outer peripheral portion of the partition member body 36, and both end portions of the circumferential groove 52 are formed at the upper end portion and the lower end portion of the partition member body 36, respectively. It is connected to each notch-shaped communication window 54, 56. A plurality of (three in the present embodiment) engagement protrusions 58 project from the upper end portion of the partition member body 36 around the upper recess 40 so as to be spaced apart in the circumferential direction.

  On the other hand, the lid member 38 has a thin disk shape, and the outer diameter of the lid member 38 is substantially the same as the outer diameter of the partition member main body 36. Here, a communication hole 60 is formed through the thickness direction in the central portion of the lid member 38 in the radial direction. The communication hole 60 has a circular shape in plan view in the present embodiment, but is not limited thereto. Further, a through hole 62 is provided on the outer peripheral side of the communication hole 60 in the lid member 38 independently from the communication hole 60. The through hole 62 includes a first small hole 64 and a second small hole 66 having the same form as the first small hole 48 and the second small hole 50 in the through hole 46 formed in the partition member main body 36. A plurality of first small holes 64 are provided at equal intervals in the circumferential direction at the radial intermediate portion of the lid member 38, and the second small holes 66 are circumferentially equal at the radial outer peripheral portion of the lid member 38. It is provided at intervals. A cutout communication window 68 is formed on the outer peripheral edge of the lid member 38. Furthermore, a plurality of (three in this embodiment) locking holes 70 are provided in the outer peripheral portion of the lid member 38 so as to be spaced apart in the circumferential direction. Such a lid member 38 is advantageously realized by pressing a metal plate such as spring steel.

  The lid member 38 is superimposed on the upper end portion of the partition member main body 36, and a plurality of locking protrusions 58 of the partition member main body 36 are inserted into the plurality of locking holes 70 of the lid member 38. As a result, the partition member main body 36 and the lid member 38 are assembled to each other while being positioned in the circumferential direction to constitute the partition member 34. In addition, the opening of the upper recess 40 of the partition member main body 36 is covered with the lid member 38, so that the gap between the lid member 38 inside the upper recess 40 and the axially opposed surface of the circular bottom 44 of the partition member main body 36. Is provided with a housing area 72 defined by the peripheral wall of the upper recess 40, the lid member 38, and the circular bottom 44. In other words, the accommodation region 72 extends with a substantially constant circular cross section in the axial direction inside the radial central portion of the partition member 34. In particular, in this embodiment, the partition member main body 36 and the lid member 38 are aligned in the circumferential direction, so that the through hole 54 of the circular bottom 44 and the through hole 62 of the lid member 38 in the partition member main body 36 are circular. The central portion in the radial direction of the bottom portion 44 and the communication hole 60 of the lid member 38 are arranged at positions that are projected in the axial direction. Further, the communication window 54 of the partition member main body 36 and the communication window 68 of the lid member 38 are overlapped in the axial direction.

  Prior to the assembly of the diaphragm 28 to the second mounting bracket 14, the partition member 34 is fitted in the axial direction from the opening below the second mounting bracket 14, and the lid member 38 of the partition member 34. The outer peripheral portion of the second mounting bracket 14 is superposed on the step portion 20 of the second mounting bracket 14 with a seal rubber layer 26 interposed therebetween. A fixing ring 30 of a diaphragm 28 fitted in the second mounting bracket 14 is overlaid on the lower end portion of the partition member main body 36 of the partition member 34. Then, the outer diameter of the partition member main body 36 and the outer diameter of the lid member 38 are obtained by reducing the diameter of the second mounting bracket 14 by reducing the diameter of the second mounting bracket 14 by reducing the diameter of the second mounting bracket 14. Is superimposed on the inner peripheral surface of the second mounting bracket 14 via a seal rubber layer 26 that is compressed and deformed in the direction perpendicular to the axis, and the tensile deformation in the axial direction accompanying the compression deformation in the direction perpendicular to the axis of the seal rubber layer 26. Thus, the outer peripheral portion of the partition member 34 is clamped and fixed between the step portion 20 of the second mounting bracket 14 and the fixing ring 30 of the diaphragm 28. Further, the sealing rubber layer 26 attached to the stepped portion 20 is interposed between the outer peripheral portion of the lid member 38 and the overlapping surface of the stepped portion 20 while being compressed and deformed in the axial direction. The outer peripheral portion and the stepped portion 20 are fluid-tightly overlapped.

  Thereby, the partition member 34 is fixedly supported by the second mounting bracket 14, and the fluid sealing region 32 inside the second mounting bracket 14 is divided into two fluid-tightly. On one side (upper side in FIG. 1) of the fluid sealing region 32 with the partition member 34 interposed therebetween, a part of the wall portion is constituted by the main rubber elastic body 16, and based on the elastic deformation of the main rubber elastic body 16. A pressure receiving chamber 74 in which pressure fluctuation is generated is formed. Further, on the other side (lower side in FIG. 1) of the fluid sealing region 32 with the partition member 34 interposed therebetween, a part of the wall portion is constituted by the diaphragm 28, and the volume change is easy based on the elastic deformation of the diaphragm 28. An equilibration chamber 76 is formed. The pressure receiving chamber 74 and the equilibrium chamber 76 are filled with an incompressible fluid. As the sealing fluid, for example, water, alkylene glycol, polyalkylene glycol, silicone oil or the like is adopted, and in order to effectively obtain a vibration isolation effect based on a fluid action such as a resonance action of the fluid, 0.1 Pa · It is desirable to employ a low-viscosity fluid of s or less. For example, the incompressible fluid is sealed in the pressure receiving chamber 74 or the equilibrium chamber 76 by, for example, the partition member 34 or the diaphragm for the integrally vulcanized molded product of the main rubber elastic body 16 including the first and second mounting brackets 12 and 14. It is preferably realized by performing the assembly of 28 in an incompressible fluid.

  In addition, the circumferential groove 52 of the partition member main body 36 is covered fluid-tightly by the second mounting bracket 14, so that an orifice passage 78 that spirally extends around the outer peripheral portion of the partition member 34 with a predetermined length in the circumferential direction. Is formed. One end of the orifice passage 78 is connected to the pressure receiving chamber 74 through the communication window 54 of the partition member main body 36 and the communication window 68 of the lid member 38, and the other end of the orifice passage 78 is connected to the partition member. It is connected to the equilibrium chamber 76 through the communication window 54 of the main body 36. As a result, the pressure receiving chamber 74 and the equilibrium chamber 76 are communicated with each other through the orifice passage 78, and fluid flow through the orifice passage 78 is allowed between the chambers 74 and 76.

  In the present embodiment, the resonance frequency of the fluid flowing through the orifice passage 78 is effective against vibrations in a low frequency region around 10 Hz corresponding to engine shake or the like based on the resonance action of the fluid. It is tuned so that the damping effect is demonstrated. The orifice passage 78 is tuned by, for example, the rigidity of the wall springs of the pressure receiving chamber 74 and the equilibrium chamber 76, that is, the main rubber elastic body 16 corresponding to the amount of pressure change required to change the chambers 74 and 76 by a unit volume. It is possible to adjust the passage length and passage cross-sectional area of the orifice passage 78 while taking into account the characteristic values based on the respective elastic deformation amounts such as the diaphragm 28 and the diaphragm 28. In general, the pressure transmitted through the orifice passage 78 The frequency at which the phase of the change changes and becomes a substantially resonant state can be grasped as the tuning frequency of the orifice passage 78.

  The accommodation region 72 formed in the partition member 34 communicates with the pressure receiving chamber 74 through the through hole 62 and the communication hole 60 of the lid member 38 and communicates with the equilibrium chamber 76 through the through hole 46 of the partition member main body 36. Has been. In addition, the storage area 72 is formed by the cover member 38 being closely overlapped and fixed to the upper end portion of the partition member main body 36 before the partition member 34 is fixed to the second mounting bracket 14. It may be formed, or when the partition member 34 is attached to the second mounting member 14, a pinching action exerted between the step 20 of the second mounting member 14 and the axial direction of the fixing ring 30 of the diaphragm 28. The lid member 38 may be formed by being closely adhered to the upper end portion of the partition member main body 36 using the above.

  In this accommodation area 72, a rubber elastic film 80 as a movable rubber film is accommodated. As shown in FIGS. 5 and 6, the rubber elastic film 80 is made of a rubber elastic material and has a substantially disk shape as a whole. The thickness dimension of the rubber elastic film 80 is the axial distance between the lid member 38 and the circular bottom 44 of the partition member main body 36, which is the axial dimension of the accommodation region 72, in other words, the axial dimension of the upper recess 40. It is smaller than that. In addition, although the thickness dimension of the rubber elastic film 80 according to the present embodiment is substantially constant throughout, for example, depending on the required spring characteristics, for example, radially outward from the radial center portion It may be gradually enlarged toward the surface, or a protrusion, a groove, a recess, or the like may be formed.

  On the outer peripheral edge of the rubber elastic film 80, a seal projection 82 is integrally formed as a clamping support portion. The seal protrusion 82 extends continuously in the circumferential direction with a substantially rectangular cross section protruding outward in the axial direction from the rubber elastic film 80. That is, the seal protrusion 82 is thicker than the rubber elastic film 80 and has an annular shape. In particular, in the present embodiment, the axial dimension of the seal projection 82 is made larger than the axial dimension of the accommodation region 72. Further, the outer diameter dimension of the seal projection 82 is slightly smaller than the diameter dimension of the upper recess 40 of the partition member main body 36 that is the dimension perpendicular to the axis of the accommodation region 72.

  Here, a relief hole 84 is formed through the central portion of the rubber elastic film 80 in the radial direction. The relief hole 84 extends in a substantially constant circular cross section in the axial direction extending parallel to the thickness direction of the rubber elastic film 80. In short, one circular relief hole 84 is formed at the center of the disk-shaped rubber elastic film 80. The diameter of the relief hole 84 is smaller than the inner diameter of the through hole 46 (first small hole 48) of the partition member main body 36. In this embodiment, the communication hole 60 of the lid member 38 is used. The diameter dimension is substantially the same.

  Further, around the relief hole 84, a pressure-receiving chamber side cylindrical projection 86 is integrally projected on one surface (upper in FIG. 1) of the rubber elastic film 80. The pressure receiving chamber side cylindrical protrusion 86 has a substantially cylindrical shape with an inner hole having the same size as the diameter of the relief hole 84, and one peripheral edge of the relief hole 84 in the rubber elastic film 80. It extends axially coaxially with the relief hole 84 on the side. Since one end of the relief hole 84 is opened outward in the axial direction through the inside of the pressure-receiving chamber side cylindrical projection 86, one opening (surface) of the relief hole 84 is The pressure receiving chamber side cylindrical protrusion 86 is configured to include a protruding front end surface.

  Further, in particular, the other side of the rubber elastic film 80 (in FIG. 1, on the surface opposite to the pressure receiving chamber side cylindrical projection 86 sandwiching the relief hole 84 in the rubber elastic film 80, that is, around the relief hole 84. On the lower surface, an equilibrium chamber side cylindrical projection 88 projects integrally. The equilibrium chamber side cylindrical projection 88 according to this embodiment has substantially the same size and shape as the pressure receiving chamber side cylindrical projection 86, and has an inner hole having the same size as the diameter of the relief hole 84. It has a substantially cylindrical shape. The equilibrium chamber side cylindrical projection 88 extends in the axial direction coaxially with the relief hole 84 and the pressure receiving chamber side cylindrical projection 86 on the other peripheral edge side of the relief hole 84 in the rubber elastic film 80. Since the other end of the relief hole 84 is opened outward in the axial direction through the inside of the equilibrium chamber side cylindrical projection 88, the other opening (surface) of the relief hole 84 is It is configured to include the protruding front end surface of the equilibrium chamber side cylindrical protrusion 88.

  That is, in the present embodiment, the peripheral wall portion of the relief hole 84, the pressure receiving chamber side cylindrical projection 86, and the equilibrium chamber side cylindrical projection 88 cooperate to be larger than the thickness dimension of the rubber elastic film 80. A cylindrical portion having an axial dimension is configured, and the cylindrical portion is disposed so as to penetrate the central portion in the radial direction of the rubber elastic film 80, and is approximately equal distance from both surfaces of the rubber elastic film 80 outward in the axial direction. It has a protruding shape. As a result, the thin plate-like portion of the rubber elastic film 80 is formed in the radial direction in which the pressure-receiving chamber side and equilibrium chamber side cylindrical protrusions 86 and 88 are projected and the seal protrusion 82 are integrally formed. It is set as the radial direction intermediate part between outer peripheral parts. In particular, the axial dimension of the relief hole 84 and the pressure receiving chamber side and equilibrium chamber side projections 86 and 88 in the central portion in the radial direction of the rubber elastic membrane 80 is made larger than the axial dimension of the housing region 72, and It is slightly smaller than the axial dimension of the seal projection 82 of the rubber elastic film 80.

  Such a rubber elastic film 80 is fitted in the upper recess 40 of the partition member main body 36, and the lower end surface of the seal protrusion 82 formed on the outer peripheral edge of the rubber elastic film 80 is the circular bottom of the partition member main body 36. 44 is superposed on the outer peripheral portion of 44. In particular, since the outer diameter of the seal protrusion 82 is slightly smaller than the diameter of the upper recess 40, the rubber elastic film 80 can be obtained by fitting the seal protrusion 82 into the upper recess 40. And a centering function in which the partition member main body 36 is positioned coaxially. As a result, the central axis of the circular bottom 44 of the partition member main body 36 and the central axis of the relief hole 84 of the rubber elastic film 80 are positioned substantially on the same line, and the other of the relief holes 84 (lower in FIG. 1). The protruding front end surface of the equilibrium chamber side cylindrical protrusion 88 and the radial center portion of the circular bottom 44 are positioned opposite to each other in the axial direction. When the rubber elastic film 80 is fitted in the upper recess 44 in this way, the protruding tip portion of the pressure receiving chamber side cylindrical projection 86 and the upper end portion of the seal projection 84 are more axial than the opening end surface of the upper recess 44. Protruded outward.

  Further, the lid member 38 is superimposed on the upper end portion of the partition member main body 36, and the lid member 38 and the partition member main body 36 are coaxially aligned. Are aligned. Here, the protruding front end surface of the pressure-receiving chamber side cylindrical protrusion 86 is positioned opposite to the periphery of the communication hole 60 in the radial center portion of the lid member 38 in the axial direction. Then, the cover member 38 is closely overlapped with the upper end portion of the partition member main body 36 to form the accommodating region 72, and as a result, the seal protrusion 82 protruding from the upper recess 40 and the pressure receiving chamber side cylindrical protrusion are formed. The lid member 38 is pressed against the portion 86 in the axial direction.

  As a result, the seal protrusion 82 is compressed and deformed in the axial direction on the outer peripheral side of the housing region 72 between the lid member 38 and the circular bottom 44, and the upper end surface of the seal protrusion 82 is The lower end surfaces are in close contact with the lid member 38 and the circular bottom 44, respectively. Further, along with the bulging deformation in the direction perpendicular to the axis due to the compressive deformation in the axial direction of the seal protrusion 82, the outer peripheral surface of the seal protrusion 82 is against the peripheral wall surface of the upper recess 40 constituting the peripheral wall portion of the housing region 72. Have been closely. As a result, the outer peripheral edge portion of the rubber elastic film 80 is fixedly supported by the partition member 34 fixed to the second mounting bracket 14, and the outer peripheral edge portion of the rubber elastic film 80 and the accommodation region 72. Free fluid flow between the walls is prevented.

  Further, the pressure receiving chamber side cylindrical projection 86 and the equilibrium chamber side cylindrical projection 88 are axially arranged based on being sandwiched between the lid member 38 and the circular bottom 44 at the radial center side of the accommodation region 72. And the projecting tip surface of the pressure-receiving chamber side cylindrical projection 86 is in close contact with the communication hole 60 in the lower end surface of the lid member 38 and the projecting tip surface of the equilibrium chamber side cylindrical projection 88. Is in intimate contact with the radially central portion of the circular bottom 44. Thereby, one opening (upper in FIG. 1) of the relief hole 84 in the rubber elastic film 80 is connected to the pressure receiving chamber 74 through the inside of the pressure receiving chamber side cylindrical projection 86 and the communication hole 60 of the lid member 38. On the other hand, the other opening (lower in FIG. 1) of the relief hole 84 is fluid-tightly closed by the circular bottom 44 through the protruding tip surface of the equilibrium chamber side cylindrical protrusion 88. .

  In addition to the fact that the protruding front end surface of the equilibrium chamber side cylindrical projection 88 is in contact with the circular bottom 44 of the partition member main body 36 over its entire circumference, particularly in the present embodiment, the pressure receiving chamber side cylindrical projection The protruding front end surface of the portion 86 is in contact with the lid member 38 over the entire circumference. As is clear from the above description, the pressure receiving chamber side contact member disposed on one surface side (the upper side in FIG. 1) of the rubber elastic film 80 includes the lid member 38. The equilibrium chamber side abutting member disposed on the other surface (lower side in FIG. 1) of the rubber elastic film 80 includes the circular bottom 44 of the partition member main body 36. Further, in this embodiment, the contact portion of the pressure receiving chamber side cylindrical projection 86 in the pressure receiving chamber side contact member is constituted by the radial center portion of the lid member 38 and is formed in the radial center portion. The communication hole 60 and the opening portion of the pressure receiving chamber side cylindrical projection 86 are overlapped in the axial direction. Thus, the opening on the pressure receiving chamber 74 side of the relief hole 84 is directly connected to the communication hole 60 of the lid member 38 and is always in communication with the pressure receiving chamber 74.

  Further, the outer peripheral edge portion of the rubber elastic film 80 provided with the seal protrusion 82 and the radial center portion including the pressure-receiving chamber side and equilibrium chamber side cylindrical protrusions 86 and 88 are the lid member 38 and the partition member main body 36. Are supported in a compressed state between the circular bottom portions 44 of the two. Here, the axial dimension of the radial center portion including the pressure receiving chamber side and equilibrium chamber side cylindrical projections 86 and 88 in the rubber elastic film 80 is made smaller than the axial dimension of the seal projection 82. Therefore, between the lid member 38 and the circular bottom portion 44, the pre-compression amount of the central portion in the radial direction of the rubber elastic film 80 is made smaller than the pre-compression amount of the seal protrusion 82. As a result, the central portion in the radial direction of the rubber elastic film 80 is difficult to be displaced even when a small pressure is applied thereto, while the outer peripheral edge of the rubber elastic film 80 is not easily displaced even when a large pressure is applied thereto. It is in a state.

  On the other hand, in the rubber elastic film 80, a radial intermediate portion between the central portion in the radial direction and the outer peripheral edge portion is arranged so as to spread in a direction perpendicular to the axial direction at a substantially central portion in the axial direction of the housing region 72. The lid member 38 opposed to the other side and the circular bottom 44 opposed to the other side in the axial direction are spaced apart from each other by a substantially equal distance. The pressure of the pressure receiving chamber 74 is applied to one surface (upper in FIG. 1) of the radial intermediate portion of the rubber elastic film 80 through the through hole 62 of the lid member 38 and the circular bottom 44 The pressure of the equilibrium chamber 76 is applied to the other surface (lower side in FIG. 1) of the intermediate portion in the radial direction of the rubber elastic film 80 through the through hole 46.

  Accordingly, when the radial intermediate portion of the rubber elastic film 80 is displaced by elastic deformation based on the relative pressure difference between the pressure receiving chamber 74 and the equilibrium chamber 76, the pressure fluctuation in the pressure receiving chamber 74 is absorbed. That is, the hydraulic pressure absorbing mechanism according to the present embodiment includes the rubber elastic film 80, the through hole 46 of the partition member main body 36, and the through hole 62 of the lid member 38.

  Further, the intermediate portion in the radial direction of the rubber elastic film 80 is displaced in the thickness direction and comes into contact with the circular bottom 44 of the lid member 38 or the partition member main body 36, whereby the amount of displacement in the thickness direction of the rubber elastic film 80 is reduced. The hydraulic pressure absorbing action of the pressure receiving chamber 74 due to the displacement of the rubber elastic film 80 is limited. As is clear from this, the rubber elastic film 80 is opposed to the both sides in the thickness direction at a predetermined distance, and the displacement amount on both sides in the thickness direction of the rubber elastic film 80 is reduced by the contact of the rubber elastic film 80. The displacement amount limiting member to be limited includes the lid member 38 and the circular bottom portion 44 of the partition member main body 36.

  In particular, in the present embodiment, a vibration isolation effect based on the hydraulic pressure absorption effect of the pressure receiving chamber 74 due to elastic deformation of the rubber elastic film 80 at the time of vibration input in the middle frequency range of about 20 to 40 Hz corresponding to idling vibration, low-speed booming sound, and the like. The natural frequency of the rubber elastic film 80 is tuned so that the (vibration insulation effect based on the low dynamic spring characteristic) is effectively exhibited.

  In this state, when a normal vibration or load is input between the first mounting bracket 12 and the second mounting bracket 14, the protruding tip surface of the equilibrium chamber side cylindrical projection 88 has a circular bottom. 44, and the other opening (lower in FIG. 1) of the relief hole 84 is maintained in the closed state so that the pressure receiving chamber side and equilibrium chamber side cylindrical protrusions 86 in the rubber elastic film 80 are maintained. , 88, the amount of compressive deformation of the central portion in the radial direction is set.

  On the other hand, when excessive vibration or load is input between the first mounting bracket 12 and the second mounting bracket 14 and a large negative pressure in question is generated in the pressure receiving chamber 74, it is also shown in FIG. As described above, a negative pressure is exerted on the rubber elastic film 80 including the pressure receiving chamber side and equilibrium chamber side cylindrical protrusions 86 and 88, and the rubber elastic film 80 is displaced toward the pressure receiving chamber 74 side. Along with this, the pressure-receiving chamber side cylindrical projection 86 is compressed and deformed in the axial direction between the lid member 38 and the rubber elastic film 80, and the equilibrium chamber-side cylindrical projection 88 is displaced toward the pressure receiving chamber 74 side. The amount of compressive deformation of the central portion in the radial direction provided with the pressure receiving chamber side and equilibrium chamber side cylindrical protrusions 86 and 88 in the rubber elastic film 80 is set so as to be separated from the circular bottom 44 of the partition member main body 36. Yes. When the protruding front end surface of the equilibrium chamber side cylindrical projection 88 is separated from the circular bottom 44 and the other opening of the relief hole 84 is opened in the receiving area 72, the relief hole 84 is in an open state. The pressure receiving chamber 74 and the equilibrium chamber 76 are the movable rubber film in the communication hole 60 of the lid member 38, the inside of the pressure receiving chamber side cylindrical portion 86, the relief hole 84, the inside of the equilibrium chamber side cylindrical portion 88, and the accommodating region 72. Short-circuit is made through a region between 80 and the circular bottom 44, through a through hole 46 in the circular bottom 44.

  In the automobile engine mount 10 having the above-described structure, a relatively large pressure fluctuation is generated in the pressure receiving chamber 82 when vibrations in a low frequency region such as an engine shake which is a problem during traveling are input. Since this pressure is large, the rubber elastic film 80 tuned to a small amplitude cannot substantially absorb the pressure in the pressure receiving chamber 74. Further, particularly in a state where no negative pressure is generated in the pressure receiving chamber 74, the protruding tip surface of the equilibrium chamber side cylindrical protrusion 88 is brought into fluid tight contact with the circular bottom 44, and the relief hole 84 is blocked. Maintained. Accordingly, absorption of pressure fluctuation in the pressure receiving chamber 74 due to elastic deformation of the rubber elastic film 80 and pressure leakage of the pressure receiving chamber 74 through the relief hole 84 are suppressed, and therefore effective between the pressure receiving chamber 74 and the equilibrium chamber 76. As a result, a sufficient pressure difference is generated, and a sufficient amount of fluid flows through the orifice passage 78. Therefore, based on the fluid action such as the resonance action of the fluid through the orifice passage 78, an effective anti-vibration effect (high damping effect) is exhibited against low-frequency vibration such as engine shake.

  In addition, when an idling vibration that is a problem when the vehicle is stopped or a vibration in a medium frequency range such as a low-speed booming sound that is a problem when traveling is performed, a pressure fluctuation with a small amplitude is caused in the pressure receiving chamber 74. At that time, since the frequency range of the vibration is higher than the tuning frequency of the orifice passage 78, the orifice passage 78 is substantially closed due to an increase in fluid flow resistance due to an anti-resonant action. In view of this, a significant high dynamic spring resulting from the substantial blockage of the orifice passage 78 by absorbing the pressure fluctuation of the pressure receiving chamber 74 based on the elastic deformation of the rubber elastic film 80 tuned to the middle frequency range. Will be avoided. Therefore, a good anti-vibration effect (vibration insulation effect based on the low dynamic spring characteristics) against vibration in the middle frequency range is exhibited.

  In the embodiment in which the pressure fluctuation of the pressure receiving chamber 74 is absorbed by the elastic deformation of the rubber elastic film 80, the pressure is extremely small. Therefore, the balance chamber side cylindrical protrusion 88 is caused by the negative pressure action of the pressure receiving chamber 74. Therefore, a negative pressure that is large enough to be displaced away from the circular bottom 44 of the partition member main body 36 is less likely to be generated in the pressure receiving chamber 74. As a result, the state where the central portion in the radial direction of the rubber elastic film 80 is supported by pressure between the lid member 38 and the circular bottom portion 44 is maintained, and based on the displacement caused by the deformation of the intermediate portion in the radial direction of the rubber elastic film 80. Thus, the intended hydraulic pressure absorption effect can be stably obtained.

  By the way, when an automobile travels over a step or travels on a road surface with large unevenness and a shocking load is input between the first mounting bracket 12 and the second mounting bracket 14, the main rubber elastic body 16 is suddenly moved. As a result of excessive elastic deformation, an excessive negative pressure may be generated in the pressure receiving chamber 74 to the extent that cavitation bubbles, which are the cause of abnormal noise, are generated.

  Therefore, in the automotive engine mount 10 according to the present embodiment, the rubber elastic film 80, the pressure receiving chamber side cylindrical protrusion 86, and the equilibrium chamber side cylindrical protrusion are in the stage of a large negative pressure before the generation of the cavitation bubbles. When a negative pressure is applied to the portion 88, the radial direction of the rubber elastic membrane 80 provided between the cover member 38 and the circular bottom portion 44 in the axial direction and including the pressure-receiving chamber side and equilibrium chamber side cylindrical protrusions 86, 88. Based on the setting of the aforementioned spring characteristic in the central portion, the equilibrium chamber side cylindrical projection 88 is separated from the circular bottom 44 and the closed state of the relief hole 84 is released. As a result, the pressure receiving chamber 74 and the equilibrium chamber 76 are communicated with each other through the relief hole 84, the pressure in the pressure receiving chamber 74 and the pressure in the equilibrium chamber 76 are brought into an equilibrium state, and the overnegative pressure state of the pressure receiving chamber 74 is eliminated. As a result, the generation of cavitation bubbles is advantageously suppressed, and problematic abnormal noises and vibrations are prevented.

  Here, in the automotive engine mount 10 according to the present embodiment, the relief mechanism for eliminating the overnegative pressure state of the pressure receiving chamber 74 is integrated with the relief hole 84 formed in the rubber elastic film 80 and the rubber elastic film 80. In addition to the pressure receiving chamber side cylindrical projection 86 and the equilibrium chamber side projection 88 formed, the lid member 38, the communication hole 60 formed in the lid member 38, the circular bottom 44 of the partition member main body 36, and the circular bottom 44 are formed. It is comprised including the through-hole 46 made. That is, the relief mechanism is configured to include many of the members or parts constituting the hydraulic pressure absorbing mechanism that absorbs the pressure fluctuation in the pressure receiving chamber 74. As a result, an increase in the number of parts associated with forming the relief mechanism separately from those members or parts can be suppressed, and improvement in manufacturing efficiency and cost reduction can be advantageously achieved.

  In addition, since the relief mechanism is formed independently of the orifice passage 78 and the orifice passage 78 is formed on the outer peripheral side of the relief mechanism in the partition member 34, the design freedom of the orifice passage 78 is effectively ensured. The In addition, there is no possibility that the fluid leaks through the relief hole when a fluid flow action through the orifice passage occurs due to, for example, forming a relief hole in the wall of the orifice passage. Accordingly, an excellent orifice effect can be obtained based on the fact that a sufficient fluid flow amount through the orifice passage 78 is ensured.

  Particularly in the present embodiment, the balance chamber side cylindrical projection 88 is provided on the opposite side of the pressure receiving chamber side cylindrical projection 86 around the relief hole 84 of the rubber elastic membrane 80, thereby providing a rubber elastic membrane. The spring characteristics in the thickness direction of the portion where the relief hole 84 and the pressure receiving chamber side cylindrical projection 86 are formed in 80 are highly tuned.

  Further, the rubber elastic film 80 is sucked toward the pressure receiving chamber 74 by the excessive negative pressure action of the pressure receiving chamber 74, and the pressure receiving chamber 74 and the equilibrium chamber 76 are short-circuited through the relief hole 84, so that the pressure receiving chamber 74. After the overnegative pressure state is resolved, the other peripheral edge of the relief hole 84 (lower in FIG. 1) of the rubber elastic film 80 is brought into contact with the circular bottom 44 of the partition member main body 36 again. Thus, the closed state of the relief hole 84 is maintained. In this case, the other opening of the relief hole 84 is formed by a protruding tip surface of the equilibrium chamber side cylindrical projection 88, and the rubber elastic film 80 is formed on the circular bottom 44 via the equilibrium chamber side cylindrical projection 88. Since it hits, based on the buffering action by the elasticity of the equilibrium chamber side cylindrical projection 88, the generation of a loud hitting sound associated with the hitting can be effectively reduced.

  Further, the radial center portion of the rubber elastic film 80 in which the pressure receiving chamber side cylindrical protrusion 86 and the equilibrium chamber side cylindrical protrusion 88 are formed, and the seal protrusion formed on the outer peripheral edge of the rubber elastic film 80. 82 is compressed between the lid member 38 and the circular bottom 44 of the partition member main body 36 in the axial direction, so that the center portion of the rubber elastic film 80 and The outer peripheral part is made difficult to deform. As a result, the rubber elastic film 80 is stably accommodated in the accommodating region 88, and the pressure fluctuation in the pressure receiving chamber 82 is efficiently absorbed by the elastic deformation of the radial intermediate portion having a large effective area. For this reason, it is possible to stably obtain an anti-vibration effect with respect to vibrations in the middle frequency range such as idling vibration and low-speed booming noise, which are the problems described above.

  Further, in this embodiment, the seal protrusion 82 of the rubber elastic film 80 is compressed and deformed between the circular bottom portion 44 of the partition member main body 36 and the cover member 38 in the axial direction, thereby causing the rubber to swell. The outer peripheral edge portion of the elastic film 80 is fluid-tightly overlapped with the peripheral wall portion of the accommodation region 72 via the seal protrusion 82. That is, the rubber elastic film 80 has a movable film structure. As a result, pressure leakage through the gap between the outer peripheral edge portion of the rubber elastic membrane 80 and the peripheral wall portion of the partition member main body 36 is further advantageously suppressed, and further stable securing of the fluid flow rate through the orifice passage 78 is ensured. Can be illustrated.

  Further, in the present embodiment, the lid member 38 includes a pressure receiving chamber side abutting member that abuts the pressure receiving chamber side cylindrical projection 86 and a displacement amount limiting member that limits the amount of displacement in one of the thickness directions of the rubber elastic film 80. In addition to being configured, the equilibrium chamber side abutting member that abuts the equilibrium chamber side cylindrical projection 88 and the displacement amount limiting member that limits the displacement amount of the rubber elastic film 80 in the thickness direction other are partition members. It is constituted by a circular bottom 44 of the main body 36. The partition member body 36 and the lid member 38 constitute a part of the partition member 34 that partitions the pressure receiving chamber 74 and the equilibrium chamber 76. In other words, since the pressure receiving chamber side and equilibrium chamber side contact members and the displacement amount limiting member are configured using the partition member 34, there is no need to newly provide the contact member and the displacement amount limiting member. An increase in the number of points and a complicated structure are prevented.

  In the present embodiment, a communication hole 60 having an inner diameter smaller than the outer diameter of the pressure receiving chamber side cylindrical projection 86 is formed in the contact portion of the pressure receiving chamber side cylindrical projection 86 in the lid member 38. . The communication hole 60 is positioned at the center of the relief hole 84. That is, the opening on the pressure receiving chamber 74 side of the relief hole 84 is directly connected to the communication hole 60 of the lid member 38 and is always in communication with the pressure receiving chamber 74. Thereby, when the opening end of the equilibrium chamber side cylindrical projection 88 is separated from the circular bottom 44 of the partition member main body 36 and the relief hole 84 is in an open state, the pressure receiving chamber 74 and the equilibrium chamber 76 are used for relief. The hole 84 is short-circuited by a short flow path that opens directly to the pressure receiving chamber through the communication hole 60, and generation of cavitation bubbles is more effectively suppressed.

  Therefore, in the automobile engine mount 10 having the structure according to this embodiment, the degree of freedom of tuning of the orifice passage 78 and the like is improved while advantageously reducing the manufacturing process, reducing the cost, and reducing the size. Thus, the desired vibration-proofing effect can be obtained stably.

  The embodiments of the present invention have been described in detail above. However, the present invention is not limited to the specific descriptions in the embodiments, and various changes, modifications, and improvements based on the knowledge of those skilled in the art. Needless to say, any of these embodiments can be included in the scope of the present invention without departing from the spirit of the present invention. For example, the shape, size, structure, arrangement, number, and the like of the partition member 34, the rubber elastic film 80, the relief hole 84, the pressure receiving chamber side cylindrical protrusion 86, and the like are not limited to those illustrated.

  Hereinafter, some aspects different from the above embodiment will be illustrated and exemplified. In each of the following aspects, members and parts having substantially the same structure as those of the above-described embodiment are denoted by the same reference numerals as those of the above-described embodiment, and detailed description thereof is omitted.

  First, in the said embodiment, the protrusion front-end | tip part of the pressure-receiving chamber side cylindrical protrusion 86 is made into the annular | circular shape extended continuously in the circumferential direction, and the protrusion front-end | tip surface contact | abuts the cover member 38 over the perimeter. However, for example, as shown in FIG. 8 in the second aspect of the present invention, the protruding tip portion of the pressure-receiving chamber side cylindrical protrusion 86 is partially brought into contact with the lid member 38. Also good. In the aspect illustrated in FIG. 8, the protruding tip portion of the pressure-receiving chamber side cylindrical protrusion 86 has U-shaped groove shapes extending radially inward and outward at a plurality of locations on the circumference (for example, four locations located equally). A notch 90 is formed. The pressure receiving chamber side cylindrical protrusion 86 is in contact with the lid member 38 only in a portion where the notches 90 are not formed. Thus, by adjusting the contact area of the pressure receiving chamber side cylindrical protrusion 86 with respect to the lid member 38 by forming the notches 90 with an appropriate size, shape and number, the pressure receiving chamber side cylindrical protrusion It is possible to adjust the spring characteristics in the axial compression direction 86 (the elastic deformation direction during the negative pressure action of the pressure receiving chamber 74) with a large degree of freedom.

  In the embodiment shown in FIG. 8, the notch 90 is formed in the pressure receiving chamber side cylindrical projection 86, so that the relief hole 84 is directly connected to the pressure receiving chamber 74 through the communication hole 60 of the lid member 38. In addition, the pressure receiving chamber 74 also enters the pressure receiving chamber 74 through the first and second small holes 64 and 66 from the accommodating region 72 located on the outer peripheral side of the pressure receiving chamber side cylindrical projection 86 in the partition member 34. It is communicated. In short, the first and second small holes 64 and 66 also function as communication holes that allow the inside of the pressure receiving chamber side cylindrical projection 86 to communicate with the pressure receiving chamber 74.

  In the above embodiment, the pressure receiving chamber side cylindrical projection 86 and the equilibrium chamber side cylindrical projection 88 have substantially the same shape and size. For example, as shown in FIG. The direction dimension and the thickness dimension in the direction perpendicular to the axis may be different from each other. Specifically, FIG. 8 shows an aspect in which the thickness dimension of the pressure receiving chamber side cylindrical projection 86 is set smaller than the thickness dimension of the equilibrium chamber side cylindrical projection 88. Accordingly, it is possible to appropriately adjust the axial compression spring characteristics by making the pressure receiving chamber side cylindrical projection 86 thin while securing the shape retention rigidity by the thick equilibrium chamber side cylindrical projection 88. The pressure receiving chamber side cylindrical projection 86 and the equilibrium chamber side cylindrical projection 88 do not have to have a constant inner and outer diameter dimension over the entire axial length thereof. For example, it is possible to improve the stability of elastic deformation by gradually reducing the outer diameter dimension toward the axially projecting tip and adopting a tapered outer peripheral surface.

  Further, the equilibrium chamber side cylindrical protrusion 88 is not an essential constituent requirement. For example, in the third aspect of the present invention shown in FIG. 9, a pedestal 92 serving as an equilibrium chamber side abutting member is projected from the circular bottom 44 of the partition member main body 36 toward the accommodation region 72. . The illustrated pedestal portion 92 is integrally formed by pressing the circular bottom portion 44, but may be formed by fixing a separate pedestal to the circular bottom portion 44. The other peripheral edge of the relief hole 84 in the rubber elastic film 80 (the lower side in FIG. 9) is superimposed on the upper surface of the pedestal 92.

  By providing such a pedestal portion 92, an elastic deformation allowable space of the rubber elastic film 80 is secured between the flat rubber elastic film 80 and the circular bottom 44 on the equilibrium chamber side (lower side in FIG. 9). However, the opening of the relief hole 84 toward the equilibrium chamber can be brought into contact with the closed state. In addition, as shown in FIG. 9, by adopting such a pedestal portion 92, the present invention can be carried out without adopting the equilibrium chamber side cylindrical projection (88). It becomes.

  Further, in the above embodiment, the diameter of the relief hole 84 is the same as the diameter of the communication hole 60 formed in the lid member 38 as the pressure receiving chamber side contact member. The sheath shape is not limited. For example, the diameter of the communication hole 60 can be increased or decreased in consideration of the cross-sectional shape and size of the relief hole 84 as in the embodiment shown in FIGS.

  Further, for example, as in the fourth aspect of the present invention shown in FIG. 10, the housing recess that opens concavely toward the housing region 72 at the portion where the pressure receiving chamber side cylindrical projection 86 contacts the lid member 38. 94 may be provided. The tip of the pressure receiving chamber side cylindrical projection 86 is inserted into the receiving recess 94, and the tip end surface of the pressure receiving chamber side cylindrical projection 86 is overlapped with the flat upper bottom surface of the receiving recess 94. Touching. By providing such a housing recess 94, the positioning effect of the pressure receiving chamber side cylindrical projection 86 and the effect of improving the shape stability during elastic deformation of the pressure receiving chamber side cylindrical projection 86 can be achieved.

  Further, the seal protrusion 82 that is integrally formed on the outer peripheral edge of the rubber elastic film 80 and is supported by pressing between the lid member 38 and the circular bottom 44 is not an essential component in the present invention. For example, in the embodiment shown in FIG. 10 described above, the outer peripheral edge portion of the rubber elastic film 80 is opposed to the peripheral wall portion of the accommodation region 72 with a slight gap therebetween. In short, the outer diameter of the rubber elastic membrane 80 is slightly smaller than the inner diameter of the accommodation region 72. The gap size is set so that the pressure fluctuation in the pressure receiving chamber 74 is sufficiently generated when the low frequency large amplitude vibration is input. As a result, the rubber elastic membrane 80 is held in position while the cylindrical projections 86 and 88 on the pressure receiving chamber side and the equilibrium chamber side are elastically sandwiched between the lid member 38 and the circular bottom portion 44 in the central portion. The outer peripheral portion can be displaced by a predetermined amount within the accommodation region 72. And based on this displacement, the pressure difference between the pressure receiving chamber and the equilibrium chamber is absorbed, and the movable plate function can be exhibited.

  In the above-described embodiment, the communication hole 60 formed in the pressure receiving chamber side contact member is formed in the portion in contact with the pressure receiving chamber side cylindrical projection 86 at the radial center of the lid member 38. It is also possible to form the communication hole other than the contact portion.

  For example, as shown in the fifth aspect of the present invention in FIG. 11, the relief hole 84 is first formed from the accommodation region 72 located on the outer peripheral side of the pressure receiving chamber side cylindrical projection 86 in the partition member 34. In addition, the pressure receiving chamber 74 may be communicated with the second small holes 64 and 66. That is, in this embodiment, the communication hole 60 of the lid member 38 is not formed as compared with the structure of the second embodiment of the present invention shown in FIG. In this aspect, the inside of the pressure-receiving chamber side cylindrical projection 86 is always communicated with the upper region in the accommodation region 72 through the notch 90. The upper region is always in communication with the pressure receiving chamber 74 through the first and second small holes 64 and 66 formed in the lid member 38. Therefore, in this embodiment, the relief hole 84 is communicated with the pressure receiving chamber 74 through the first and second small holes 64 and 66 from the accommodating region 72 communicated with the notch 90. As is clear from this, in the present embodiment, the first and second small holes 64 and 66 are communication holes that allow the inside of the pressure receiving chamber side cylindrical projection 86 to communicate with the pressure receiving chamber 74. .

  The notch 90 formed in the pressure receiving chamber side cylindrical protrusion 86 generates an excessive negative pressure in the pressure receiving chamber 74, and the pressure receiving chamber side cylindrical protrusion 86 is interposed between the cover member 38 and the rubber elastic film 80 in the axial direction. As shown in FIG. 12, even when the open end of the equilibrium chamber side cylindrical projection 88 is separated from the circular bottom 44 of the partition member main body 36 by being compressed and deformed, as shown in FIG. The inside of the cylindrical protrusion 86 can be maintained in a communicating state. Therefore, when a large negative pressure is generated in the pressure receiving chamber 74, the pressure receiving chamber 74 and the equilibrium chamber 76 are located between the movable rubber film 80 and the lid member 38 in the through hole 62 of the lid member 38 or the accommodation region 72. Area, communication path 98, pressure receiving chamber side cylindrical portion 86, relief hole 84, equilibrium chamber side cylindrical portion 88, area between movable rubber film 80 and circular bottom 44 in storage area 72, circular bottom The short circuit state is developed through the through holes 46 of 44. Thereby, the same effect as said 1st embodiment can be exhibited.

  Moreover, in the said embodiment, although the rubber elastic film | membrane 80 was coaxially arrange | positioned on the center axis | shaft of the mount 10 and the partition member 34, the arrangement | positioning position of a rubber elastic film is not limited. Further, the relief hole 84 is provided in the central portion in the radial direction of the rubber elastic membrane 80. However, the relief chamber side cylindrical projection 86 is formed at a position deviating from the radial center of the rubber elastic membrane. It is also possible to provide the hole in a position deviated from the mount center axis. Furthermore, the pressure-receiving chamber side cylindrical protrusion 86 and the short-circuit flow path formed by the relief hole are not limited to one, but are located at a plurality of positions with respect to one rubber elastic film 80. It is also possible to form a short-circuit channel. It is also possible to provide a plurality of short circuit channels as a whole mount by disposing a plurality of rubber elastic films 80 on one mount and forming relief holes in them.

  Further, in the automobile engine mount according to the embodiment, the structure provided with the single orifice passage is adopted. For example, as the orifice passage, the first orifice passage and the higher frequency region than the first orifice passage are used. A structure provided with a second orifice passage tuned to the above may be employed. Thus, for example, when vibrations that are likely to cause problems are present in the low-frequency range and the middle to high-frequency range, the resonance frequency of each fluid that flows through the first orifice passage and the second orifice passage is reduced. By tuning to the frequency range and the high frequency range, the vibration isolation effect can be effectively exhibited against a plurality of vibrations.

  In addition, in the above-described embodiments, specific examples of applying the present invention to an automobile engine mount have been described. However, the present invention is not limited to an automobile body mount, a differential mount, a suspension member mount, etc. Any of them can be applied to the body vibration isolator.

It is a longitudinal cross-sectional view of the engine mount for motor vehicles as one Embodiment of this invention, Comprising: The figure equivalent to the II cross section of FIG. The top view which shows the state which assembled | attached the rubber elastic film to the partition member which comprises some engine mounts for the said cars. The one side view of the partition member. The bottom view of the partition member. The longitudinal cross-sectional view of the rubber elastic membrane. The top view of the elastic rubber board. The longitudinal cross-sectional view which shows the principal part of one action | operation form of the engine mount for the said motor vehicles. The longitudinal cross-sectional view which shows the principal part of the engine mount for motor vehicles as another specific example (2nd aspect) of this invention. The longitudinal cross-sectional view which shows the principal part of the engine mount for motor vehicles as another specific example (3rd aspect) of this invention. The longitudinal cross-sectional view which shows the principal part of the engine mount for motor vehicles as another specific example (4th aspect) of this invention. The longitudinal cross-sectional view which shows the principal part of the engine mount for motor vehicles as another specific example (5th aspect) of this invention. The longitudinal cross-sectional view which shows the operation form different from FIG. 11 in the engine mount for motor vehicles shown by FIG.

Explanation of symbols

10: Automotive engine mount, 12: First mounting bracket, 14: Second mounting bracket, 16: Rubber elastic body, 28: Diaphragm, 36: Partition body, 38: Lid member, 44: Circular bottom, 46: through-hole, 60: communication hole, 62: through-hole, 74: pressure receiving chamber, 76: equilibrium chamber, 78: orifice passage, 80: rubber elastic membrane, 84: relief hole, 86: pressure receiving chamber side cylindrical protrusion Part

Claims (8)

The first mounting member and the second mounting member are connected by a main rubber elastic body, and a pressure receiving chamber in which a part of a wall portion is configured by the main rubber elastic body and incompressible fluid is enclosed, and a flexible An equilibrium chamber in which a part of the wall portion is formed of an insulative film and in which an incompressible fluid is sealed is formed, and the pressure receiving chamber and the equilibrium chamber are communicated with each other by an orifice passage. A movable rubber film is disposed therebetween so that 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 of the movable rubber film. In a fluid-filled vibration isolator that constitutes a hydraulic pressure absorption mechanism that absorbs minute pressure fluctuations in the pressure receiving chamber by
A relief hole is formed in the movable rubber film so as to penetrate therethrough, and a pressure-receiving chamber side cylindrical projection protruding on the one surface of the movable rubber film around the relief hole is formed integrally with the movable rubber film. On the other hand, a pressure receiving chamber side abutting member is disposed on one surface side of the movable rubber film at the site where the relief hole is formed, and an equilibrium chamber side abutting member is disposed on the other surface of the movable rubber film. The projecting tip surface of the pressure receiving chamber side cylindrical projection constituting one opening of the relief hole is brought into contact with the pressure receiving chamber side contact member, and the inside of the pressure receiving chamber side cylindrical projection Is communicated with the pressure receiving chamber through a communication hole formed in the pressure receiving chamber side abutting member, and the other opening peripheral edge of the relief hole is closely in contact with the equilibrium chamber side abutting member over the entire circumference. The relief hole is closed in the state and closed by the equilibrium chamber side contact member. Fluid filled type vibration damping device that.   In the contact portion of the pressure receiving chamber side cylindrical projection in the pressure receiving chamber side contact member, the pressure receiving chamber side cylindrical projection is directly opened to the inside of the pressure receiving chamber side cylindrical projection. The fluid filled type vibration damping device according to claim 1, wherein the communication hole for communicating with the pressure receiving chamber is formed.   The fluid-filled vibration isolator according to claim 1 or 2, wherein the relief hole in the movable rubber film is formed at one position in the center of the movable rubber film.   The fluid according to any one of claims 1 to 3, wherein a protruding front end surface of the pressure receiving chamber side cylindrical protrusion is in contact with the pressure receiving chamber side contact member over the entire circumference thereof. Enclosed vibration isolator.   The movable rubber film is disposed in a compressed state in a thickness direction between the pressure receiving chamber side contact member and the equilibrium chamber side contact member around the relief hole. The fluid-filled vibration isolator according to any one of the above.   An equilibrium chamber side cylindrical protrusion protruding on the other surface of the movable rubber film around the relief hole is formed integrally with the movable rubber film and constitutes the other opening of the relief hole. The fluid filled type vibration damping device according to any one of claims 1 to 5, wherein a protruding front end surface of the equilibrium chamber side cylindrical protrusion is in contact with the equilibrium chamber side contact member.   A thick annular pinching support portion is integrally formed at the outer peripheral edge of the movable rubber film, and the pinching support portion is pinched and supported in a compressed state by a support member fixed to the second mounting member. The micro pressure fluctuation in the pressure receiving chamber is absorbed based on elastic deformation of the movable rubber film on the inner peripheral side of the pinching support portion. The fluid-filled vibration isolator described in 1.   Displacement amount limiting members are disposed opposite to each other on both sides in the thickness direction of the movable rubber film, and the thickness of the movable rubber film is determined by contacting the movable rubber film with the displacement amount limiting member. The fluid-filled vibration isolator according to any one of claims 1 to 7, wherein a displacement amount to both sides in the direction is limited.

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