JP3994397B2 - Fluid filled vibration isolator - Google Patents

Description

  The present invention relates to a vibration isolator that is suitably employed for, for example, an automobile engine mount or body mount, and in particular, exhibits a vibration isolating characteristic that is exhibited based on the flow action of an incompressible fluid sealed inside. The present invention relates to a fluid-filled vibration isolator that can be switched according to the situation.

  Conventionally, as a type of vibration isolator that is mounted between members constituting a vibration transmission system, a fluid-filled vibration isolator that obtains a vibration isolating effect by using a fluid action of a fluid sealed inside. It has been known. Such a vibration isolator generally connects a first attachment member attached to one member constituting a vibration transmission system and a second attachment member attached to the other member with a main rubber elastic body, A pressure receiving chamber and an equilibrium chamber are formed on both sides of the partition member supported by the mounting member, and the pressure receiving chamber and the equilibrium chamber are communicated with each other by an orifice passage. Further, when vibration is input, a vibration isolation effect is obtained based on the resonance action of the fluid that is caused to flow through the orifice passage based on the relative pressure fluctuation caused between the pressure receiving chamber and the equilibrium chamber. (See Patent Document 1 etc.)

  By the way, in such a fluid-filled vibration isolator, the vibration frequency region in which the vibration isolating effect based on the fluid flow action is effectively exhibited is a limited frequency region in which the orifice passage is tuned. On the other hand, the frequency range in which the anti-vibration effect is required for the anti-vibration device generally covers a plurality of or a wide frequency range. For example, engine mounts for automobiles are required to have anti-vibration effects against low-frequency vibrations such as engine shake during driving and anti-vibration effects against high-frequency vibrations such as running-over noise, while idling vibration when stopping. Therefore, an anti-vibration effect with respect to vibrations in the middle frequency range is required.

  Therefore, in order to effectively exhibit the vibration-proofing effect based on the fluid flow action with respect to a plurality of vibrations in a wide frequency range, the present applicant has previously described Patent Document 1 (Japanese Patent Laid-Open No. 2005-133, 1994). 2000-257665), a first orifice passage tuned to a low frequency region and a second orifice passage tuned to a medium frequency region are formed, and the second orifice passage is opened and closed by a pneumatic actuator. By doing so, the first orifice passage and the second orifice passage are selectively functioned, and a movable plate is disposed in the partition wall partitioning the pressure receiving chamber and the equilibrium chamber, so that the first and second orifice passages are substantially formed. Fluid-filled type anti-vibration structure that maintains vibration-proof performance against high-frequency vibrations by absorbing pressure fluctuations in the pressure-receiving chamber at the time of vibration input in the high frequency range It has proposed a system.

  However, in the conventional fluid-filled vibration isolator described in Patent Document 1, a pneumatic actuator is disposed outside the flexible membrane that defines the equilibrium chamber, and an output member of the actuator is provided. By pressing the flexible membrane against the opening of the second orifice passage, the opening to the equilibrium chamber in the second orifice passage is fluid-tightly closed with the flexible membrane and the second orifice passage is blocked. I was supposed to. For this reason, there has been a problem that the flexible film originally formed of a thin rubber film so as to be easily deformed is easily damaged by repeated pressing by the output member of the actuator, and it is difficult to sufficiently secure its durability. .

  In addition, since the second orifice passage is closed by pressing the central portion of the flexible membrane with the output member of the actuator, particularly in a state where the second orifice passage is closed and blocked, The central portion of the flexible membrane is restrained by the actuator, and the effective free length of the flexible membrane is reduced. For this reason, the volume change allowable amount of the equilibrium chamber is limited, and there is a possibility that the desired vibration isolation effect is difficult to be exhibited.

  Furthermore, it is necessary to secure a pneumatic actuator placement area outside the flexible membrane that defines the equilibrium chamber, especially to avoid interference with the actuator when the flexible membrane bulges and deforms. In order to avoid damage to the flexible membrane, it is necessary to ensure a relatively large space between the flexible membrane and the actuator. For this reason, the overall size of the vibration isolator tends to be large, and this may be a serious problem in recent automobile anti-vibration apparatuses in which the installation space is particularly limited.

  In addition, in the fluid-filled vibration isolator having the conventional structure, the opening to the equilibrium chamber of the second orifice passage is covered with a flexible film from the equilibrium chamber side. The fluid pressure exerted from the pressure receiving chamber through the orifice passage is acted in the direction of pushing back the actuator through the flexible membrane and opening the second orifice passage. Therefore, there are cases where it is difficult to keep the second orifice passage in a closed state, and there is also a problem that it is difficult to stably exhibit the intended vibration isolation performance. In order to maintain the second orifice passage in the shut-off state, it is conceivable to increase the pressing force of the flexible membrane by the actuator, but this will further reduce the durability of the flexible membrane. In addition, there is a problem that it becomes difficult to open the second orifice passage by releasing the pressing force applied to the flexible membrane by the actuator, so this is not an effective solution.

  In addition, a special space is required for the arrangement of the movable plate, and there is a problem that the space for the pneumatic actuator and the orifice passage is limited, and it is difficult to secure a sufficient space for the movable plate. For this reason, there has been a problem that it is difficult to obtain a sufficient anti-vibration effect against vibration in a high frequency range by the movable plate.

  In addition, since the movable plate absorbs the pressure fluctuation of the pressure receiving chamber even when the vibration is input in the middle frequency range based on the displacement, the amount of fluid flow through the second orifice passage when the vibration is input in the middle frequency range. However, there is a possibility that the anti-vibration effect against the vibration in the middle frequency range by the second orifice passage may be lowered.

  In order to solve such a problem, for example, as described in Patent Document 2 (Japanese Patent Laid-Open No. 10-38017) which is an earlier application of the present applicant, a part of the wall portion of the pressure receiving chamber is provided. A movable plate is installed and an independent air chamber is formed behind it. When vibration is input in the middle frequency range, negative pressure is applied to the independent air chamber, and the movable plate is sucked and restrained by negative pressure. Is also possible. However, the formation of the independent air chamber behind the movable plate requires the formation of an air chamber and an air intake / exhaust passage independent of the pneumatic actuator as described above, which complicates the structure and increases the number of parts. Difficult, further increase in size is unavoidable, and is not always an effective measure.

JP 2000-257665 A Japanese Patent Laid-Open No. 10-38017

  Here, the present invention has been made in the background as described above, and the problem to be solved is a fluid having a pneumatic actuator for opening and closing an orifice passage and switching vibration-proof characteristics. The object of the present invention is to realize a sealed vibration isolator with excellent durability and compactness.

  In addition, the present invention is advantageous in vibration-proofing performance against vibrations in the high frequency range while sufficiently securing the vibration-proofing effects against vibrations in the low and medium frequency ranges by the first orifice passage and the second orifice passage. It is another object of the present invention to provide a fluid-filled vibration isolator having a novel structure that can be obtained.

  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, a feature of the present invention is that the first mounting member and the second mounting member are connected by the main rubber elastic body, and the partition member is supported by the second mounting member so that the partition member is sandwiched between the first mounting member and the second mounting member. On the other side, a part of the wall portion is formed of the main rubber elastic body to form a pressure receiving chamber into which vibration is input, and one side of the wall portion is formed of a flexible film on the other side of the partition member. Forming a volume-variable equilibrium chamber having a portion formed therein, and enclosing an incompressible fluid in the pressure receiving chamber and the equilibrium chamber, while forming an orifice passage communicating the pressure receiving chamber and the equilibrium chamber with each other; In the fluid-filled vibration isolator which obtains a vibration isolating effect based on the flow action of the fluid that is allowed to flow through the orifice passage, a first orifice passage tuned to a low frequency region and an intermediate frequency are used as the orifice passage. Tuned to The second orifice passage is provided, while the working air chamber is formed inside the partition member, and the air passage for applying air pressure to the working air chamber from the outside is formed, and the equilibrium chamber in the working air chamber is formed. A side wall portion is formed of a partition rubber film, and an output portion is provided at a central portion of the partition rubber film to form a pneumatic actuator, and the output portion of the pneumatic actuator is disposed inside the partition member. An urging means for urging the output portion toward the opening toward the equilibrium chamber, and opposing the opening to the balance chamber side in the second orifice passage so as to be able to approach / separately displace; The output portion is pressed against the opening to the equilibrium chamber side by the urging means in a state where atmospheric pressure is applied to the working air chamber, and the second orifice passage is maintained in a shut-off state. And the When the negative pressure is applied to the air chamber, the output portion is separated from the opening toward the balance chamber against the urging force of the urging means, and the second orifice passage is brought into communication. In addition, the wall portion on the pressure receiving chamber side in the working air chamber is formed of a movable rubber plate, and the pressure of the high frequency and small amplitude in the pressure receiving chamber in a state where atmospheric pressure is exerted on the working air chamber. In the fluid-filled vibration isolator, the fluctuation is absorbed by the elastic displacement of the movable rubber plate, and the displacement of the movable rubber plate is restricted by applying a negative pressure to the working air chamber.

  In such a fluid-filled vibration isolator having a structure according to the present invention, the second orifice passage is opened and closed without a flexible membrane by the pneumatic actuator disposed inside the partition member. The Rukoto. Therefore, it becomes possible to prevent damage to the flexible film caused by pressing the output member of the pneumatic actuator against the flexible film formed of a thin rubber film, and durability of the flexible film It is possible to improve the performance.

  Further, since the second orifice passage is communicated / blocked by the output member of the pneumatic actuator without passing through the flexible membrane, the second orifice passage is closed under the condition that the second orifice passage is blocked. However, the effective free length of the flexible membrane can be avoided from being limited by the pneumatic actuator, and the effective free length of the flexible membrane and thus the volume change allowance of the equilibrium chamber can be advantageously ensured.

  Further, by arranging the pneumatic actuator inside the partition member, it is not necessary to provide a space for arranging the pneumatic actuator outside the flexible membrane, and at the same time, the flexible membrane bulges out. It is not necessary to secure a space for avoiding interference with the pneumatic actuator during deformation. Therefore, it is possible to reduce the size of the entire vibration isolator.

  Furthermore, in the present invention, the opening to the equilibrium chamber side of the second orifice passage is closed from the inside of the partition member by the output member of the pneumatic actuator, so that the second orifice from the pressure receiving chamber at the time of vibration input. The pressure transmitted through the passage is not exerted in the direction of opening the opening with respect to the output member of the pneumatic actuator closing the second orifice passage. Therefore, the second orifice passage is stably kept in the shut-off state, and the vibration-proof characteristics in the communication state of the second orifice passage and the vibration-proof characteristics in the shut-off state are alternative. And it can be exhibited stably.

  Further, in the present invention, the movable rubber plate constituting a part of the wall portion of the working air chamber at the time of vibration input in a high frequency range in which both the first orifice passage and the second orifice passage are substantially closed. Based on this displacement, the pressure fluctuation of the pressure receiving chamber is absorbed, and effective vibration isolation performance can be exhibited even for high frequency vibrations in which the first orifice passage and the second orifice passage are substantially closed.

  In addition, such a movable rubber plate is movable by the negative pressure of the working air chamber in a state where a negative pressure is exerted on the working air chamber in order to maintain the second orifice passage in a communicating state at the time of vibration input in the middle frequency range. The rubber plate is sucked and a restraining force is applied. Therefore, at the time of vibration input in the middle frequency range, absorption of pressure fluctuations in the pressure receiving chamber due to displacement of the movable rubber plate is prevented, and the amount of fluid flow through the second orifice passage is advantageously ensured. The effective vibration-proofing effect against the medium frequency vibration can be sufficiently exhibited by the two orifice passages.

  By the way, in the present invention, it is preferable to employ a configuration in which a restraining member that limits the elastic deformation amount is fixed to the movable rubber plate.

  In the fluid-filled vibration isolator having the structure according to the present invention adopting such a configuration, the displacement of the movable rubber plate is more reliably performed by applying a negative pressure to the working air chamber while allowing a minute displacement of the movable rubber plate. Since the deformation can be suppressed, the vibration isolation performance based on the low dynamic spring action at the time of high frequency and small amplitude vibration input and the vibration isolation performance by the second orifice passage at the time of medium frequency medium amplitude vibration input are improved. Improvements can be realized at a higher level.

  More preferably, a configuration in which a metal plate or a resin plate is employed as the restraining member and its outer peripheral portion is elastically fluidly connected to the partition member by a rubber elastic body is employed.

  More preferably, a configuration is adopted in which an elastic contact protrusion is formed on the surface of a metal plate or a resin plate constituting the restraining member.

  In the fluid-filled vibration isolator having the structure according to the present invention adopting such a configuration, the displacement amount of the restraining member is buffered and ensured by bringing the elastic contact protrusion into contact with the partition member. It becomes possible to restrict to.

  In the present invention, preferably, a configuration in which the output portion is formed by fixing a hard reinforcing member to a central portion of the partition rubber film is employed.

  In the fluid-filled vibration isolator having the structure according to the present invention adopting such a configuration, the output portion can be more reliably pressed against the opening, and the communication / blocking of the second orifice passage can be switched. Since it becomes possible to carry out more reliably, the target anti-vibration performance can be expressed more effectively.

  Further, in the present invention, preferably, in the working air chamber, an intermediate support portion that extends between opposing surfaces of the partition rubber film and the movable rubber plate is fixedly provided on the partition member, The biasing means is configured by disposing a coil spring between the output portion of the partition rubber film.

  In the fluid-filled vibration isolator having the structure according to the present invention adopting such a configuration, the biasing means can be advantageously realized, and in particular, the coil made of metal that is easy to adjust the spring characteristics and has less sag. Since it becomes possible to employ a spring, the stability and durability of the operation can be further improved.

  As a more preferable aspect, the intermediate support portion has a plate shape extending in a direction substantially orthogonal to the opposing direction of the partition rubber film and the movable rubber plate, and the partition rubber film side and the movable rubber plate side communicate with each other. A configuration in which communication holes for transmitting air pressure at least are formed is employed.

  In the fluid-filled vibration isolator having a structure according to such an embodiment, compared to the case where air pressure is separately applied to the rubber film side and the rubber plate side partitioned by the intermediate support portion, the air pressure is applied. Since it is only necessary to provide an air passage for exerting air pressure on one of these, the structure can be simplified.

  Further, as a more preferable aspect, a central recess opening toward the pressure receiving chamber side is formed with respect to the partition member main body, and a fitting ring in which a partition rubber film is vulcanized and bonded to the outer peripheral edge portion thereof is press-fitted. As a result, the lower region communicates with the second orifice passage so that it faces the opening of the second orifice passage toward the equilibrium chamber side, while the lower region is connected to the upper orifice passage. An intermediate support portion in which a movable rubber plate is fitted by press-fitting a metal ring that is vulcanized and bonded to the outer peripheral surface of the movable rubber plate, and has a shallow central recess that opens upward. The members are sequentially superposed on the partition member main body from above in a close contact state. Here, the movable rubber plate is vulcanized and bonded with a metal plate as a constraining plate embedded in the center portion, and a substantially annular elastic support projecting toward both surfaces at the outer peripheral edge of the constraining plate. The intermediate portion is supported by being sandwiched between the intermediate support portion and the lid member, and based on the elastic deformation of these elastic support portions, the central portion where the restraint plate is embedded and fixed is allowed to be elastically displaced as a whole. The configuration described above can be adopted.

  The fluid-filled vibration isolator having the structure according to the present invention adopting such a configuration can be easily assembled and manufactured with a simple structure.

  In the present invention, preferably, the first orifice passage is formed so that the pneumatic actuator is provided in the central portion of the partition member while the outer peripheral portion of the partition member extends in the circumferential direction. Is done.

  In the fluid-filled vibration isolator having the structure according to the present invention adopting such a configuration, the passage of the first orifice passage is provided in the outer peripheral portion of the partition member while securing the formation space of the pneumatic actuator at the center of the partition member. The length can be set large, and the tuning degree of freedom of the first orifice passage can be advantageously ensured.

  The opening to the pressure receiving chamber side of the second orifice passage is formed in the outer peripheral portion of the partition member, while the opening to the equilibrium chamber side is formed from the outer peripheral portion of the second orifice passage to the pneumatic actuator. A configuration in which an opening is formed in the central portion by extending to the formed central portion is also preferably employed.

  In the fluid-filled vibration isolator having the structure according to the present invention adopting such a configuration, the output length of the pneumatic actuator formed in the central portion while sufficiently securing the passage length of the second orifice passage, The opening and closing of the opening on the equilibrium chamber side of the second orifice passage can be advantageously realized.

  In the present invention, it is preferable that the second mounting member has a substantially cylindrical shape, and the first mounting member is spaced apart on one opening side of the second mounting member so that one opening is formed by the main rubber elastic body. The other opening of the second mounting member is fluid-tightly closed with the flexible membrane, while the partition member is inserted into the second mounting member and fixed in place. By doing so, the structure which formed the said pressure receiving chamber and the said equilibrium chamber on the both sides of the axial direction on both sides of this partition member is employ | adopted.

  In the fluid-filled vibration isolator having the structure according to the present invention adopting such a configuration, the pressure receiving chamber and the equilibrium chamber are provided on both sides of the partition member on the mount center axis serving as the center axis of the second mounting member. It can be formed with good space efficiency. Therefore, a compact fluid-filled vibration isolator can be realized more advantageously with a simple structure.

  As is clear from the above description, in the fluid-filled vibration isolator constructed according to the present invention, the vibration isolation for the low-frequency and medium-frequency vibrations by the first orifice passage and the second orifice passage is provided. While sufficiently securing the effect, it is possible to advantageously obtain a vibration isolation performance against vibrations in a high frequency range. Further, since the second orifice passage can be opened and closed without a flexible membrane by disposing the pneumatic actuator inside the partition member, a fluid-filled vibration isolator having a compact and simple structure Can be realized with the excellent durability of the flexible membrane.

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

  First, FIG. 1 shows a vibration isolating mount 10 for an automobile as an embodiment of the present invention. This anti-vibration mount 10 has a structure in which a first mounting member 12 as a first mounting member and a second mounting member 14 as a second mounting member are elastically connected by a main rubber elastic body 16. The first mounting bracket 12 is attached to the power unit side, while the second mounting bracket 14 is attached to the body side of the automobile via the bracket 18 and the leg portion 20, so that the power unit is attached to the body. It is designed to support vibration isolation. In the following description, the vertical direction basically means the vertical direction in FIG.

  More specifically, the first mounting bracket 12 has a substantially inverted truncated cone block shape. A mounting bolt 22 is integrally formed on the end surface on the large diameter side so as to protrude upward in the axial direction.

  On the other hand, the second mounting bracket 14 has a substantially cylindrical shape with a large diameter as a whole. In addition, the second mounting member 14 includes a constricted portion 24 as an annular groove at the axially upper end thereof. The constricted portion 24 is recessed inward in the radial direction and extends in the circumferential direction. In this embodiment, the constricted portion 24 has a substantially constant cross-sectional shape over the entire circumference of the second mounting member 14. In particular, the upper opening portion in the axial direction of the second mounting bracket 14 constituting one wall portion in the width direction of the constricted portion 24 is a tapered portion 26 that gradually expands toward the opening side.

  In the second mounting bracket 14 having such a structure, the first mounting bracket 12 is disposed on substantially the same central axis so as to be spaced apart from the opening portion on the upper side in the axial direction. A main rubber elastic body 16 is disposed between the first mounting bracket 12 and the second mounting bracket 14, and the first mounting bracket 12 and the second mounting bracket are arranged by the main rubber elastic body 16. 14 are elastically connected.

  The main rubber elastic body 16 has a truncated cone shape as a whole, and is vulcanized and bonded to the main rubber elastic body 16 so that the first mounting member 12 is inserted from the end surface on the small diameter side. Further, the opening portion on the upper side in the axial direction of the second mounting bracket 14 is overlapped and vulcanized and bonded to the outer peripheral surface of the large-diameter side end portion of the main rubber elastic body 16. In this embodiment, the main rubber elastic body 16 is an integrally vulcanized molded product including the first mounting bracket 12 and the second mounting bracket 14.

  Further, the opening of the second mounting bracket 14 is vulcanized and bonded to the outer peripheral surface of the main rubber elastic body 16 in this way, so that the opening on the upper side in the axial direction of the second mounting metal 14 is the main rubber elastic body. 16 is closed fluid-tightly. A mortar-shaped large-diameter recess 28 is formed on the large-diameter side end face of the main rubber elastic body 16 and is opened in the second mounting bracket 14. An annular surface 30 that extends in the direction perpendicular to the axis is formed at the opening peripheral edge of the large-diameter recess 28.

  Furthermore, a seal rubber layer 32 is formed on the inner peripheral surface of the second mounting member 14. The seal rubber layer 32 is formed integrally with the main rubber elastic body 16, and the inner peripheral surface of the second mounting bracket 14 is covered by the seal rubber layer 32 over substantially the entire surface.

  In addition, a fitting rubber 34 is attached to the outer peripheral surface of the second mounting bracket 14 and filled in the constricted portion 24. In the present embodiment, the fitting rubber 34 is formed integrally with the main rubber elastic body 16, and is, for example, a through hole (not shown) provided in the constricted portion 24 of the second mounting bracket 14. ), The fitting rubber 34 and the main rubber elastic body 16 are integrally connected.

  Further, the partition member 36 and the flexible film 56 are sequentially fitted into the second mounting bracket 14 from the opening portion below the axial direction, and are fitted and fixed to the second mounting bracket 14. .

  The partition member 36 is formed by sequentially superposing upper and lower partition blocks 42 and 38 each having a thick, substantially disk shape and a thin, substantially disk-shaped lid member 54, and as a whole is substantially the same. It is a circular block shape. The flexible film 56 is formed of a thin rubber film, has a substantially thin dome shape with a slack, and a cylindrical fitting 58 is vulcanized and bonded to the outer peripheral surface thereof. Has been.

  Then, the partition member 36 and the flexible film 56 are sequentially inserted in the axial direction from the lower opening with respect to the second mounting bracket 14, and thereafter, the diameter of the second mounting bracket 14 is reduced such as an eight-way stop. As a result, the outer peripheral surfaces of the partition member 36 and the fitting member 58 are fitted and fixed to the second mounting member 14. In addition, the lower end opening edge part of the 2nd attachment metal fitting 14 is crimped, and it is set as the latching | locking part 59 latched by the lower end part of the fitting metal fitting 58, and preventing coming-out. Further, under such an assembled state, the partition member 36 and the fitting fitting 58 are overlapped with each other in the axial direction, and the annular surface 30 of the main rubber elastic body 16 and the locking portion 59 of the second mounting fitting 14 are connected. In between, it is fixedly positioned in the axial direction. Furthermore, the seal rubber layer 32 is disposed between the partition member 36 and the fitting member 58 and the second mounting member 14 in a sandwiched state.

  Accordingly, a pressure receiving chamber 60 in which a part of the wall portion is configured by the main rubber elastic body 16 is formed on the upper side in the axial direction of the partition member 36, while the wall on the lower side in the axial direction of the partition member 36. An equilibrium chamber 64 is formed, part of which is made of a flexible film 56. The pressure receiving chamber 60 and the equilibrium chamber 64 are fluid-tightly partitioned with respect to the external space, and incompressible fluids such as water, alkylene glycol, polyalkylene glycol, and silicone oil are sealed therein, respectively.

  The pressure receiving chamber 60 is configured to generate a pressure change based on elastic deformation of the main rubber elastic body 16 when a vibration is input between the first mounting bracket 12 and the second mounting bracket 14. On the other hand, the balance chamber 64 is easily allowed to change its volume by the deformation of the flexible membrane 56 being easily generated. Note that the fluid is sealed in the pressure receiving chamber 60 and the equilibrium chamber 64 by, for example, fitting the partition member 36 and the flexible film 56 into the second mounting bracket 14 in the incompressible fluid, and then mounting the second mounting It can be advantageously performed by drawing the metal fitting 14 or the like.

  The lower partition block 38 is formed with a central recess 40 that opens to the center of the upper surface, and a central opening window 62 is formed through the center of the bottom wall of the central recess 40. The output member 66 is incorporated in the central recess 40 in the accommodated state, and the opening of the central recess 40 is covered fluid-tightly by the upper partition block 42.

  The output member 66 includes a partition rubber elastic body 68 as a partition rubber film having a tapered cylindrical shape that gradually decreases in diameter toward the lower side. A central metal fitting 69 is vulcanized and bonded to the small-diameter side end of the partition rubber elastic body 68, and a fitting tube metal fitting 70 is vulcanized and bonded to the opening peripheral edge of the large-diameter side.

  The central metal fitting 69 has a substantially cup shape, and substantially the entire inner and outer surfaces are covered with an adherent rubber layer integrally formed with the partition rubber elastic body 68 to form an output portion 71. And, by this adherent rubber layer, a sealing rubber 88 is formed on the outer surface of the bottom wall of the central metal fitting 69, while a stopper rubber 90 is formed protruding upward on the peripheral edge of the opening of the central metal fitting 69. Yes. Moreover, the fitting cylinder fitting 70 has a substantially cylindrical shape, and its upper end portion in the axial direction is bent inward in the radial direction.

  The output member 66 is housed in the central recess 40 of the lower partition block 38 as a whole, and the fitting member 70 is assembled by being press-fitted and fixed to the opening of the central recess 40. Yes. Thereby, the central recess 40 of the lower partition block 38 covered with the upper partition block 42 is fluid-divided into two fluid-tight by the output member 66, so that the orifice communication is provided between the output portion 71 and the central recess 40. A region 72 is defined, and a first air chamber 73 is defined between the output member 66 and the upper partition block 42.

  Further, the output member 66 incorporated in the partition member 36 has a bottom wall portion of the output portion 71 to which the sealing rubber 88 is attached to the central opening window 62 formed in the bottom wall portion of the central recess 40. Are opposed to each other in the axial direction. Further, the first air chamber 73 accommodates a compression coil spring 76 as an urging means, and a urging force in the separation direction is exerted between the opposing surfaces of the output member 66 and the upper partition block 42. And the bottom wall part of the output part 71 is hold | maintained in the state contact | abutted with respect to the bottom wall part of the center recess 40 based on the elasticity of the partition rubber elastic body 68, and the urging | biasing force of the compression coil spring 76. The central opening window 62 is sealed in a fluid-tight manner.

  Further, the upper partition block 42 has a shallow central recess 43 formed on the center upper surface, and a metal ring 48 fitted with a substantially disc-shaped movable rubber plate 46 on the outer periphery thereof is formed on the upper partition block 42. On the other hand, it is press-fitted and fluid-tight. The lower surface of the movable rubber plate 46 is positioned below the upper surface of the bottom wall of the central recess 43, and a second air chamber 74 is formed between the opposed surfaces of the movable rubber plate 46 and the central recess 43. Has been. The second air chamber 74 is communicated with the first air chamber 73 by a small-diameter communication hole 44 formed in the central portion of the central recess 43 so as to penetrate the upper partition block 42 in the axial direction. As a result, a fluid-tight working air chamber 75 is formed.

  In addition, a metal plate 50 as a restraining member is fixed to the movable rubber plate 46 in the central portion in an embedded state, and an elastic contact protrusion 52 as an elastic support portion is provided at the outer peripheral edge of the metal plate 50. Projecting is provided on both sides of the movable rubber plate 46.

  The elastic contact protrusions 52 are in contact with the bottom surface of the central recess 43 and the lower surface of the lid member 54 to elastically support the movable rubber plate 46 inside the partition member 36.

  Here, a circular center hole 55 is formed in the center of the lid member 54 so as to penetrate the lid member 54 in the axial direction. With the central hole 55, the movable rubber plate 46 constitutes a part of the bottom wall portion of the pressure receiving chamber 60.

  Thereby, the pressure fluctuation induced in the pressure receiving chamber 60 by the input of the high frequency vibration is absorbed by the displacement of the movable rubber plate 46 due to the elastic deformation of the elastic contact protrusion 52, and the vibration proof performance against the high frequency vibration. The improvement is realized.

  Since the amplitude of the low frequency vibration is larger than the amplitude of the high frequency vibration, the movable rubber plate 46 for the purpose of preventing the high frequency small amplitude vibration cannot absorb the low frequency large amplitude vibration. Therefore, the pressure fluctuation in the pressure receiving chamber 60 is effectively generated when low frequency vibration is input.

  Incidentally, an air passage 78 extending inward and outward is formed in the outer peripheral portion of the central recess 40 in the lower partition block 38. The inner opening of the air passage 78 is connected to the working air chamber 75. On the other hand, the outside opening of the air passage 78 is opened at a port portion 80 projecting from the lower partition block 38, and external air inserted from the outside through a window portion 84 formed in the second mounting bracket 14. A pipe line 82 is connected to the port unit 80.

  Thereby, although not explicitly shown in the drawing, the pressure of the working air chamber 75 can be controlled from the outside. Specifically, for example, the external space pipe line 82 connected to the port unit 80 is connected to the atmosphere and an appropriate negative pressure source via an electromagnetic switching valve, and according to the running state of the automobile. By switching the electromagnetic switching valve, it is possible to selectively cause the atmospheric pressure and the negative pressure to act on the working air chamber 75.

  In the state where the working air chamber 75 is communicated with the atmosphere, as described above, the central opening window 62 is held closed by the bottom wall portion of the output portion 71 of the output member 66, while the working air chamber 75. By applying a negative pressure to the output member 66, a driving force is exerted on the output member 66 for suction and displacement toward the working air chamber 75, while a negative pressure acts on the movable rubber plate 46, causing the working air chamber 75 to move. The suction restraining force is exerted on the. As a result, as shown in FIG. 2, the output member 66 is displaced upwardly from the central opening window 62, the central opening window 62 is opened, and the orifice communication region 72 and the equilibrium chamber 64 are in the center. While maintaining the communication state through the opening window 62, the movable rubber plate 46 is restrained by suction, and its displacement is suppressed.

  Further, as is clear from the above description, the output member 66, the upper partition block 42, the movable rubber plate 46, and the fitting tube fitting 70 form a pneumatic actuator 86 as a whole, and the partition member 36 is disposed in a housed state.

  Further, the partition member 36 is formed with a circumferential groove 92 having a substantially constant cross-sectional shape and extending in the circumferential direction so as to open to the outer circumferential surface and to have a predetermined length in the circumferential direction. One end in the circumferential direction of the circumferential groove 92 opens into the pressure receiving chamber 60 through a communication window 94 formed in the lid member 54. The other end in the circumferential direction of the circumferential groove 92 opens into the equilibrium chamber 64 through a communication hole 96 formed in the lower partition block 38. Then, the circumferential groove 92 is covered with the second mounting bracket 14 to form a first orifice passage 98 that allows the pressure receiving chamber 60 and the equilibrium chamber 64 to communicate with each other in an always open state.

  In addition, the partition member 36 is formed with an axial groove 100 that extends downward in the axial direction by a predetermined length from a communication window 94 formed in the axial direction above one end of the circumferential groove 92. A radial hole 102 is formed which extends in a tunnel shape from the lower end portion of the axial groove 100 toward the inside in the radial direction and passes through the peripheral wall portion of the central recess 40 and opens into the orifice communication region 72. Then, when the axial groove 100 is covered with the second mounting member 14, the axial groove 100 extends from the pressure receiving chamber 60, opens to the equilibrium chamber 64 through the orifice communication region 72 and the central opening window 62, and balances with the pressure receiving chamber 60. A second orifice passage 104 is formed which allows the chambers 64 to communicate with each other.

  Here, the second orifice passage 104 has a passage cross-sectional area: A ratio of passage length: L: [A / L] larger than that of the first orifice passage 98, The resonance frequency of the fluid flowing inside is tuned so that the second orifice passage 104 has a higher frequency range than the first orifice passage 98. Specifically, in the present embodiment, in the first orifice passage 98, vibration in a low frequency range of about 10 Hz corresponding to an engine shake or the like is obtained by a low dynamic spring action based on a resonance action of a fluid flowing inside the first orifice passage 98. It is tuned so that an effective anti-vibration effect is exhibited. On the other hand, in the second orifice passage 104, the low dynamic spring action based on the resonance action of the fluid flowing inside is effective for vibrations in a high frequency range of about 20 to 40 Hz corresponding to idling vibration or the like. Tuned to be demonstrated.

  Further, since the second orifice passage 104 is opened to the equilibrium chamber 64 through the central opening window 62, the central opening window 62, which is an opening portion of the second orifice passage 104 toward the equilibrium chamber 64, is provided. By opening and closing by the output member 66, the second orifice passage 104 is selectively switched between a communication state and a blocking state.

  Specifically, under the mounting state of the vibration isolating mount 10 on the automobile, the running state and the stopped state of the automobile are detected by a speed sensor or the like, and the switching valve is switched based on the difference in the vehicle state. The working air chamber 75 is connected to the atmosphere under the traveling state to maintain the second orifice passage 104 in the shut-off state, while the working air chamber 75 is connected to the negative pressure source while the automobile is stopped. The orifice passage 104 is kept in communication.

  As a result, when the automobile is running, the second orifice passage 104 is blocked, so that the amount of fluid flow through the first orifice passage 98 is advantageously ensured. Based on this, an effective anti-vibration effect is exhibited against low-frequency large-amplitude vibration such as engine shake. In addition, when the automobile is stopped, the second orifice passage 104 is communicated to cause fluid flow through the second orifice passage 104, and idling vibration or the like based on the resonance action of the fluid flow. An effective anti-vibration effect for medium frequency vibrations is exhibited.

  Therefore, in the vibration-proof mount adopting the structure according to the present invention having the above-described structure, the resonance action of the fluid flowing through the first and second orifice passages 98 and 104 and the fluctuation of the internal pressure by the movable rubber plate 46 are obtained. By absorbing this, it is possible to exhibit an effective anti-vibration effect for vibrations in a plurality of different or wide frequency ranges.

  More specifically, when high-frequency and low-frequency vibrations are input, the working air chamber 75 is maintained at substantially atmospheric pressure, the second orifice passage 104 is maintained in a closed state, and the movable rubber plate 46 can be elastically displaced. By maintaining the state, the vibration isolating effect based on the fluid flow of the first orifice passage 98 against low frequency vibrations, and the vibration isolating due to pressure absorption caused by the elastic displacement of the movable rubber 46 against high frequency vibrations. Each effect is effective.

  When medium frequency vibration is input, negative pressure is applied to the working air chamber 75 to allow the second orifice passage 104 to communicate, and at the same time, the movable rubber plate 46 is sucked and restrained by the negative pressure exerted through the communication hole 44. Therefore, when the intermediate frequency vibration is input, the movable rubber plate 46 does not absorb the fluctuation of the internal pressure of the pressure receiving chamber 60 and the second orifice passage 104 is used. A sufficient amount of fluid flow can be secured, and the anti-vibration effect against the medium frequency vibration by the second orifice passage 104 can be advantageously exhibited.

  The movable rubber plate 46 is not constrained when low-frequency vibration is input, but the low-frequency vibration such as a shake has an extremely large amplitude compared to the high-frequency vibration such as a booming sound. A decrease in the vibration isolation effect of the first orifice passage 98 due to the action hardly causes a problem.

  In this case, since the movable rubber plate 46 is incorporated in the partition member 36 in a housed state, a special space for installation is not required, and the entire vibration isolator can be reduced in size and the movable rubber plate 46 can be reduced. As a result, a sufficient space for disposing the antenna is ensured, and it is possible to advantageously realize a vibration-proofing effect against high-frequency vibration.

  Furthermore, by providing the communication hole 44 in the center of the upper partition block 42, it is possible to restrain the movable rubber plate 46 by using the negative pressure exerted on the working air chamber 75 from the outside in order to drive the pneumatic actuator 86. Therefore, there is no need to provide a new working air chamber or air pipe for restraining the movable rubber plate 46, space saving can be achieved, and the number of parts can be reduced. A compact anti-vibration mount can be realized with a simple structure.

  In addition, the metal plate 50 as a restraining member is fixed to the movable rubber plate 46 in an embedded state, and the elastic contact protrusion 52 is formed to protrude on the surface of the metal plate 50, so that the elastic contact protrusion 52 is partitioned. By abutting against the member 36, the amount of displacement of the movable rubber plate 46 can be limited in a buffering manner.

  In addition, since the pneumatic actuator 86 is assembled in the partition member 36 in the accommodated state, the second orifice passage 104 can be closed without the flexible membrane 56 being interposed. The excellent durability of the conductive film 56 can be obtained, and the effective free length of the flexible film 56 can be advantageously obtained, and stabilization of the intended vibration-proof characteristic can be realized.

  In addition, since the pneumatic actuator 86 is accommodated in the partition member 36, the output member 66 of the pneumatic actuator 86 and the flexible film 56 are positioned apart from each other without providing a special space. Therefore, it is possible to make the entire fluid-filled vibration isolator compact.

  The output member 66 covers and closes the central opening window 62, which is an opening to the equilibrium chamber 64 of the second orifice passage 104, from the inside, that is, from the inside of the output member 66. Therefore, when a large positive pressure due to the pressure fluctuation in the pressure receiving chamber 60 is exerted toward the equilibrium chamber 64 through the second orifice passage 104, the central opening window 62 is in the center with respect to the cover-covered output member 66. A direct action is avoided as a driving force in the direction in which the opening window 62 is opened, and the second orifice passage 104 is stably kept in a shut-off state, so that the desired prevention can be achieved. The vibration performance can be exhibited more stably.

  Furthermore, since the partition member 36 is used as a housing for the pneumatic actuator 86, the pneumatic actuator 86 can be realized with a simple structure with a small number of parts and in a compact manner.

  Further, in the vibration isolating mount of the present embodiment, the working air chamber 75 is set to a substantially atmospheric pressure by biasing the output member 66 toward the opening portion of the second orifice passage 104 to the equilibrium chamber 64. Since the output member 66 is pressed downward toward the central opening window 62 to hold the central opening window 62 in the shut-off state, a negative pressure that can be easily obtained in an automobile by the operation of the pneumatic actuator 86 is skillful. It can be used.

  Furthermore, in the present embodiment, the pneumatic actuator 86 is incorporated in the approximate center of the partition member 36, and the first orifice passage 98 and the second orifice passage 104 are formed in the outer peripheral portion of the partition member 36. The passage lengths of the first and second orifice passages 98 and 104 can be set large in the outer peripheral portion of the partition member 36 while ensuring a space for forming the pneumatic actuator 86 in the center of the partition member 36. The degree of freedom of tuning of the first and second orifice passages 98, 104 can be advantageously ensured.

  In the present embodiment, the pressure receiving chamber 60 and the equilibrium chamber 64 are formed on both sides in the axial direction with the partition member 36 interposed therebetween, so that the pressure receiving chamber 60 and the equilibrium chamber 64 can be formed with good space efficiency. Thus, a compact vibration-proof mount can be realized more advantageously with a simple structure.

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

  For example, the tuning frequency of the first orifice passage 98, the second orifice passage 104, and the movable rubber plate 46 is appropriately set and changed according to the vibration frequency to be damped, as in the above embodiment. It is not limited to. Specifically, for example, the first orifice passage 98 is tuned to a medium frequency frequency range such as idling vibration, and the second orifice passage 104 is tuned to a high frequency frequency range such as low-speed traveling boom noise. It is also possible to use vibration isolation by the movable rubber plate 46 for higher frequency vibrations. Further, the specific shapes and structures of the first and second orifice passages and the movable rubber plate can be appropriately changed accordingly.

  Moreover, in the said embodiment, the pressure fluctuation in the pressure receiving chamber 60 was absorbed by the displacement by using the rubber plate which fixed the metal plate 50 in the embedding state as a movable plate, However, The form of a movable plate is the said embodiment. It is not limited to those. Specifically, for example, a plate-like rubber member that is not constrained by the metal plate 50 or the like can be used as the movable plate, and the internal pressure fluctuation of the pressure receiving chamber 60 can be absorbed by the deformation.

  Further, in the above-described embodiment, the pneumatic actuator 86 is compressed as an urging means for pressing against the opening of the second orifice passage 104 on the side of the equilibrium chamber 64 when the working air chamber 75 is at substantially atmospheric pressure. Although the coil spring 76 is used, the urging means is not limited to that of the above embodiment. Specifically, for example, only the elasticity of the partition rubber elastic body 68 can be used to hold it in a contact state, or a leaf spring or the like can be used instead of the compression coil spring 76. is there.

  In addition, in the above-described embodiment, a specific example of the present invention applied to an engine mount for automobiles has been shown. However, the present invention also includes, for example, an automobile body mount, cab mount, subframe mount, diff mount, and suspension. Needless to say, the present invention can be advantageously applied to bushing, cylindrical fluid-filled engine mounts frequently used for FF type engines, and various mounting devices other than automobiles.

  In addition, although not enumerated one by one, the present invention can be carried out in a mode to which various changes, modifications, improvements, and the like are added based on the knowledge of those skilled in the art. It goes without saying that all are included in the scope of the present invention without departing from the spirit of the present invention.

It is a longitudinal section showing a fluid enclosure type vibration proof mount as one embodiment of the present invention. 2 is a cross-sectional view showing a case where a negative pressure is applied to a working air chamber 75 in the fluid-filled vibration-proof mount shown in FIG. 1. FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Anti-vibration mount 12 1st mounting bracket 14 2nd mounting bracket 16 Main body rubber elastic body 36 Partition member 46 Movable rubber plate 56 Flexible film 60 Pressure receiving chamber 64 Equilibrium chamber 68 Partition rubber elastic body 71 Output part 75 Working air Chamber 76 Compression coil spring 78 Air passage 86 Pneumatic actuator 98 First orifice passage 104 Second orifice passage

Claims (6)

The first mounting member and the second mounting member are connected by a main rubber elastic body, and the partition member is supported by the second mounting member, and the main rubber elastic body is interposed on one side of the partition member. A pressure receiving chamber in which a part of the wall is configured to receive vibration is formed, and a variable volume equilibrium chamber in which a part of the wall is configured with a flexible film on the other side across the partition member. The pressure action chamber and the equilibrium chamber are filled with an incompressible fluid, while the pressure receiving chamber and the equilibrium chamber are connected to each other to form an orifice passage so that the fluid flowing through the orifice passage In a fluid-filled vibration isolator that obtains a vibration isolation effect based on
As the orifice passage, a first orifice passage tuned to a low frequency region and a second orifice passage tuned to a medium frequency region are provided, while an operating air chamber is formed inside the partition member, and the action By forming an air passage that exerts air pressure from the outside on the air chamber, and forming a wall portion on the side of the equilibrium chamber in the working air chamber with a partition rubber film, and providing an output portion at the central portion of the partition rubber film A pneumatic actuator is configured, and the output portion of the pneumatic actuator is located in the partition member so as to be opposed to the opening to the balance chamber side in the second orifice passage so as to be able to approach / separately displace. And an urging means for urging the output portion toward the opening toward the equilibrium chamber side, and atmospheric pressure is exerted on the working air chamber through the air passage. Under the state, the output portion is pressed against the opening toward the equilibrium chamber by the biasing means, the second orifice passage is maintained in a shut-off state, and negative pressure is applied to the working air chamber. The output portion is separated from the opening portion toward the equilibrium chamber side against the urging force of the urging means so that the second orifice passage is in communication, and further in the working air chamber. The wall portion on the pressure receiving chamber side is made of a movable rubber plate, and the pressure variation of high frequency and small amplitude in the pressure receiving chamber is an elastic displacement of the movable rubber plate in a state where atmospheric pressure is exerted on the working air chamber. And a displacement of the movable rubber plate is restrained by applying a negative pressure to the working air chamber. The fluid-filled vibration isolator according to claim 1, wherein a restraining member that limits an elastic deformation amount is fixed to the movable rubber plate. The fluid-filled vibration isolator according to claim 1 or 2, wherein the output portion is formed by fixing a hard reinforcing member to a central portion of the partition rubber film. In the working air chamber, an intermediate support portion extending between opposing surfaces of the partition rubber film and the movable rubber plate is fixedly provided on the partition member, and the intermediate support portion and the output portion of the partition rubber film 4. The fluid filled type vibration damping device according to claim 1, wherein the biasing means is configured by disposing a compression coil spring between the two. The fluid according to any one of claims 1 to 4, wherein the pneumatic actuator is provided in a central portion of the partition member, and the first orifice passage is formed so that an outer peripheral portion of the partition member extends in a circumferential direction. Enclosed vibration isolator. The second mounting member has a substantially cylindrical shape, the first mounting member is spaced apart on one opening side of the second mounting member, and the one opening is fluid-tightly closed by the main rubber elastic body. While the other opening of the second mounting member is fluid-tightly closed with the flexible membrane, the partition member is inserted into and fixed to the second mounting member, thereby fixing the partition member. The fluid-filled vibration isolator according to any one of claims 1 to 5, wherein the pressure receiving chamber and the equilibrium chamber are formed on both sides in the axial direction across the wall.

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