JP2007051768A - Fluid-filled engine mount - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a fluid-filled engine mount of novel structure capable of advantageously exhibiting a vibration control effect based on the flow action of a filled incompressible fluid and effectively suppressing the occurrence of impulsive noise and vibration. <P>SOLUTION: A movable plate 50 is composed of a plate-like body formed of a rubber elastic body, while a pressure regulating plate 80 composed of a plate-like body formed of a rubber elastic body is disposed at a partition wall part 44 for partitioning an intermediate chamber 58 from a pressure receiving chamber 34, and the spring rigidity of the pressure regulating plate 80 is made larger than that of the movable plate 50. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a fluid-filled engine mount that obtains an anti-vibration effect based on the flow action of a fluid sealed inside, and more particularly, a first orifice passage and a higher frequency than the first orifice passage. The present invention relates to a fluid-filled engine mount having a novel structure that has a second orifice passage tuned in the region and can exhibit a vibration-proofing effect against vibrations in a plurality of or a wide frequency range.

  Conventionally, as a type of engine mount that is interposed between a power unit including an internal combustion engine, such as an engine, and the body, and the power unit is connected to the body in an anti-vibration manner or supported in an anti-vibration manner, the resonant action of the fluid generated when vibration is input 2. Description of the Related Art A fluid-filled engine mount that uses a fluid action such as that to obtain an anti-vibration effect is known. Such a mount connects a first mounting bracket and a second mounting bracket that are attached to one of the power unit and the body with a main rubber elastic body, and a pressure receiving chamber in which a part of the wall portion is configured with the main rubber elastic body. And a structure in which an incompressible fluid is sealed in the pressure receiving chamber and the equilibrium chamber, and both chambers communicate with each other through an orifice passage. Has been.

  By the way, it is desirable that the fluid-filled engine mount exhibits an excellent anti-vibration effect with respect to vibrations in a plurality of or a wide frequency range in consideration of the presence of a disturbance that disturbs a predetermined operation state or equilibrium state. . Especially for engine mounts used in automobiles, the frequency of the input vibration to be isolated varies depending on the driving conditions of the vehicle, etc., so the vibration isolation performance is effective against vibrations in multiple or wide frequency ranges. Specifically, for example, in addition to shake vibration in a low frequency range of about 10 Hz that is input when the vehicle travels, idling vibration in a high frequency range of about 15 to 30 Hz that is input when the vehicle is stopped. However, an anti-vibration effect is required.

  In view of the above problems, a fluid-filled engine mount has been proposed in which a first orifice passage and a second orifice passage tuned in a higher frequency range than the first orifice passage are formed. For example, Patent Document 1 (Japanese Patent Laid-Open No. 10-1332017), Patent Document 2 (Japanese Patent Laid-Open No. 8-4823), Patent Document 3 (Japanese Patent Publication No. 7-54131), Patent Document 4 (Japanese Patent Laid-Open No. 2001-336564). This is what is shown in the Gazette).

  In such an engine mount, an intermediate chamber in which a part of the wall portion is formed of a rubber elastic plate is provided between the pressure receiving chamber and the equilibrium chamber, and the pressure receiving chamber, the intermediate chamber, and the equilibrium chamber are connected to the first orifice passage and the second chamber. The two orifice passages communicate with each other. As a result, the fluid flow rate of the first orifice passage is ensured by limiting the flow rate of the fluid that can flow through the second orifice passage by the rubber elastic plate when vibration is input in the resonance frequency range of the first orifice passage. Each of the orifice passages by actively generating a fluid flow action of the second orifice passage by utilizing the resonance phenomenon of the rubber elastic plate at the time of vibration input in the resonance frequency range of the second orifice passage. An anti-vibration effect based on a fluid action such as a resonance action of the fluid through is advantageously exhibited.

  However, in such an engine mount, when a large vibration is input between the first mounting bracket and the second mounting bracket, abnormal noise or vibration may be emitted from the mount. As a result of investigations by the present inventors, in a vehicle equipped with a fluid-filled engine mount having a conventional structure as described above, abnormal noise and impact that can be felt by the occupant in the passenger compartment when traveling on a wavy road with large irregularities, etc. It has been confirmed that there are cases where

JP 10-1332017 A JP-A-8-4823 Japanese Patent Publication No. 7-54131 JP 2001-336564 A

  Here, the present invention has been made in the background as described above, and the problem to be solved is that the vibration isolation effect based on the flow action of the enclosed incompressible fluid can be advantageously exhibited. An object of the present invention is to provide a fluid-filled engine mount having a novel structure capable of effectively suppressing the occurrence of shocking abnormal noise and vibration.

  First, in the fluid-filled engine mount with the conventional structure as described above, the present inventor has conducted many experiments on the occurrence of abnormal noise and vibration, and for example, when an automobile travels on a wavy road with large irregularities. A shock vibration load is applied between the first mounting member and the second mounting member at a larger acceleration than the shake vibration having a large amplitude among vibrations input under general driving conditions. Became clear. Also, using the device model that visualized the fluid chamber, we observed the operating state of the fluid-filled engine mount when a shocking vibration load about the running of a wavy road in an actual vehicle was input. Generation of bubbles that could be solved was observed.

  From the theory of cavitation, when inputting such a shocking vibration load, bubbles that repeatedly generate, grow, collapse, and disappear in the intermediate chamber maintain a substantially spherical stability in the process from generation to growth. , Will be deformed upon collapse, will form an explosive micro jet, which is transmitted to the first mounting member and the second mounting member as a water hammer pressure, and transmitted to the body of the automobile, etc. Acquired knowledge that abnormal noise and vibration, which are the problems described above, will be generated is the mechanism of abnormal noise and vibration that has been a problem in this type of fluid-filled engine mount. It was.

  In addition, cavitation bubbles that are the basic cause of abnormal noise and vibration in question are idling that causes amplitude vibration in the resonance frequency range of the second orifice passage at a frequency higher than the resonance frequency of the first orifice passage. It was newly confirmed that the vibration generated in the intermediate chamber when an amplitude vibration larger than the vibration was input.

  Therefore, the present inventor pays attention to the inference theory that cavitation bubbles are generated due to the fact that the amplitude vibration in the predetermined size or frequency range is input as described above and the intermediate chamber is in a large decompression state, By suppressing the negative pressure in this intermediate chamber, we obtained the knowledge that cavitation bubbles would be suppressed and shocking abnormal noise and vibration could be suppressed, and the present invention was completed based on this knowledge. It was done.

  Hereinafter, the aspect of this invention made in order to solve the above-mentioned 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.

(Aspect 1 of the present invention)
A feature of the first aspect of the present invention is that the first attachment member attached to one member to be vibration-proof connected and the second attachment member attached to the other member to be anti-vibration connected are separated from each other. A pressure-receiving chamber in which a part of the wall is made of the rubber elastic body, a part of the wall made of a flexible film, and a part of the wall. Forms an intermediate chamber composed of movable plates, and arranges the intermediate chamber and the equilibrium chamber on both sides of the movable plate, and encloses the incompressible fluid in the pressure receiving chamber, the equilibrium chamber, and the intermediate chamber. Further, the pressure receiving chamber and the equilibrium chamber are communicated with each other, and the first orifice passage in which the resonance frequency of the fluid that is allowed to flow inside is tuned to the engine shake, the pressure receiving chamber and the intermediate chamber are mutually connected. Lets communicate and flow inside In a fluid-filled engine mount having a second orifice passage whose body resonance frequency is tuned to idling vibration, the movable plate is formed of a plate-like body made of a rubber elastic body, while the pressure receiving chamber and the intermediate chamber A fluid-filled engine mount in which a pressure regulating plate made of a rubber elastic body is disposed in a partition wall partitioning the partition, and the spring stiffness of the pressure regulating plate is larger than the spring stiffness of the movable plate is there.

  In the fluid-filled engine mount structured according to this aspect, pressure fluctuation is induced in the pressure receiving chamber at the time of inputting an engine shake that causes amplitude vibration in the resonance frequency range of the first orifice passage, and the pressure receiving chamber and the equilibrium chamber Based on the relative pressure difference, a fluid action such as a resonance action of the fluid is generated through the first orifice passage. By the way, because the pressure adjusting plate is arranged in the partition that separates the pressure receiving chamber and the intermediate chamber, the pressure adjusting plate directly faces the pressure receiving chamber, so that the pressure fluctuation in the pressure receiving chamber is adjusted when the shake is input. May be absorbed by the plate.

  In this case, a movable plate is provided on a part of the wall portion of the intermediate chamber, and the spring rigidity of the pressure adjustment plate is larger than the spring rigidity of the movable plate. Tuning settings for each spring stiffness, and by direct pressure regulation between the pressure receiving chamber and the intermediate chamber, the wall spring stiffness of the intermediate chamber with respect to the amplitude of the shake vibration (necessary for changing only the unit volume) The characteristic value corresponding to the pressure change amount) is sufficiently large. As a result, the hydraulic pressure absorbing action by the pressure adjusting plate when the shake vibration is input is suppressed, and a sufficient amount of fluid flow through the first orifice passage is ensured. As a result, an anti-vibration effect (vibration damping effect) can be advantageously exhibited based on the fluid flow action through the first orifice passage.

  In addition, when idling vibration, which is amplitude vibration in the resonance frequency range of the second orifice passage, is input, the flow resistance of the first orifice passage is remarkably increased and becomes substantially closed, and the pressure receiving chamber and the intermediate chamber are relatively closed. Based on the pressure difference, a fluid action such as a resonance action of the fluid is generated through the second orifice passage. In particular, since the spring stiffness of the pressure adjusting plate is greater than that of the movable plate, the pressure adjusting plate is prevented from being greatly deformed when idling vibration is input, and the pressure fluctuation in the pressure receiving chamber is effectively caused. In addition, a change in the volume of the intermediate chamber is easily allowed based on the elastic deformation of the movable plate. Therefore, a relative pressure fluctuation is effectively induced between the pressure receiving chamber and the intermediate chamber, and a sufficient amount of fluid flow through the second orifice passage is ensured between the pressure receiving chamber and the intermediate chamber. Thereby, the anti-vibration effect (vibration insulation effect) by the fluid flow action through the second orifice passage can be advantageously exhibited.

  By the way, for example, in a situation where an automobile travels on a wavy road with large unevenness, when amplitude vibration larger than idling vibration is input in a frequency range higher than the resonance frequency of the first orifice passage, The movable plate is positively or greatly elastically deformed with a large pressure fluctuation, and a large negative pressure is locally generated in the intermediate chamber due to the pressure fluctuation exerted on the intermediate chamber by the elastic deformation of the movable plate. There is a risk of being.

  Therefore, a part of the wall portion of the intermediate chamber that partitions the intermediate chamber and the equilibrium chamber is configured to include a movable plate, and another part of the wall portion of the intermediate chamber that partitions the pressure receiving chamber and the intermediate chamber is By including the adjustment plate, the pressure fluctuation exerted on the intermediate chamber by the elastic deformation of the movable plate is absorbed by the elastic deformation of the pressure adjustment plate. In particular, since the spring stiffness of the pressure adjusting plate is larger than the spring stiffness of the movable plate, the pressure adjusting plate may be more elastically deformed than the movable plate when an amplitude vibration larger than the idling vibration described above is input. This suppresses the occurrence of pressure fluctuations greater than the pressure fluctuation caused by the elastic deformation of the movable plate in the intermediate chamber. As a result, the large decompression state of the intermediate chamber due to the elastic deformation of the movable plate is eliminated, and the generation of cavitation bubbles is reduced or avoided.

  When amplitude vibration larger than idling vibration is input in a frequency range lower than the resonance frequency of the first orifice passage, the pressure fluctuation induced in the pressure receiving chamber is released to the equilibrium chamber through the first orifice passage. Therefore, an excessive negative pressure is prevented from being generated in the intermediate chamber.

  Therefore, in the fluid-filled engine mount according to this aspect, the wall portion of the intermediate chamber includes the pressure adjusting plate and the movable plate having the above-described structure, so that the first and second orifices are formed. Impact that was a problem by avoiding the large decompression state of the intermediate chamber, which is thought to be the cause of cavitation bubbles generated in the intermediate chamber, while maintaining sufficient vibration isolation effect based on the flow action of each fluid through the passage Noise and vibration can be effectively suppressed.

  The spring stiffness of the movable plate and pressure adjusting plate is the same as the relative pressure difference between the intermediate chamber and the equilibrium chamber formed on both sides of the movable plate, and the pressure receiving chamber formed on both sides of the pressure adjusting plate. This corresponds to the amount of deformation necessary to deform the movable plate and the pressure adjusting plate in the thickness direction by dynamic pressure based on the relative pressure difference between the chambers.

(Aspect 2 of the present invention)
A feature of aspect 2 of the present invention is that the fluid-filled engine mount according to aspect 1 of the present invention includes the movable plate, the pressure adjustment plate, and the intermediate chamber, and the movable plate and the pressure adjustment plate. A fluid flow path is formed in which the fluid flows and transmits pressure along with the elastic deformation of the fluid, and the resonance frequency of the fluid flow path is tuned to a higher frequency range than the resonance frequency of the second orifice passage. There is.

  In this aspect, when a small amplitude vibration is input in a frequency range higher than the resonance frequency of the second orifice passage, the pressure fluctuation exerted on the intermediate chamber based on the elastic deformation of the pressure adjusting plate is It is absorbed on the basis of elastic deformation and escapes to the equilibrium chamber. That is, when the high frequency vibration is input, fluid flow is substantially allowed between the pressure receiving chamber and the equilibrium chamber based on the elastic deformation of the pressure adjusting plate and the movable plate. Therefore, an increase in pressure fluctuation in the pressure receiving chamber is suppressed, and a significant increase in the dynamic spring is avoided, so that the vibration isolation effect can be further improved.

(Aspect 3 of the present invention)
A feature of the third aspect of the present invention is that in the fluid-filled engine mount according to the first or second aspect of the present invention, the hard partition member fixedly supported by the second mounting member is provided in the pressure receiving chamber. And a recess that opens toward the side of the equilibrium chamber in the central portion of the partition member, and the opening of the recess is covered with the movable plate in a fluid-tight manner. Thus, the intermediate chamber is formed, and the partition wall portion is constituted by the bottom wall portion of the recess, while the first orifice passage and the second orifice passage are utilized by utilizing the outer peripheral portion of the partition member. It is in having formed.

  In this aspect, the intermediate chamber, the first and second orifice passages, the movable plate, the partition wall portion, and the like are formed with a small number of parts and excellent space efficiency, so that the mount can be advantageously made compact.

(Aspect 4 of the present invention)
A feature of aspect 4 of the present invention is that, in the fluid-filled engine mount according to aspect 3 of the present invention, the second mounting member is formed in a cylindrical shape and is disposed on one opening side of the second mounting member. The first mounting member is spaced apart, and the first mounting member and the second mounting member are connected by the main rubber elastic body so that one opening of the second mounting member is fluid-tight. And the other opening of the second mounting member is covered with the flexible film, and the partition member is fitted into the second mounting member so that the main rubber elastic body and the flexible In that it is disposed between opposing surfaces of the conductive film.

  In this aspect, the structure for fixing the partition member to the second mounting member is simplified, and the pressure receiving chamber and the equilibrium chamber are formed with a small number of parts and excellent space efficiency, thereby further reducing the size. obtain.

  As is clear from the above description, in the fluid-filled engine mount structured according to the present invention, when an amplitude vibration larger than the idling vibration is input in a frequency range higher than the resonance frequency of the first orifice passage, The pressure fluctuation exerted on the intermediate chamber by the elastic deformation of the movable plate is absorbed by the elastic deformation of the pressure adjusting plate. As a result, the large decompression state of the intermediate chamber due to the deformation of the movable plate is eliminated, and the generation of cavitation bubbles is suppressed. As a result, the shocking abnormal noise and vibration that have been problems can be effectively suppressed. .

  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 of the present invention. The engine mount 10 includes a first mounting bracket 12 as a first mounting member and a second mounting bracket 14 as a second mounting member that are spaced apart from each other. Two mounting brackets 14 are elastically connected to each other by a main rubber elastic body 16. The mount 10 is attached to a power unit of an automobile as one member to which the first mounting bracket 12 is vibration-proof connected, and to the vehicle body as the other mounting member to which the second mounting bracket 14 is vibration-proof connected. The power unit is attached to an automobile by being attached, and the power unit is supported in a vibration-proof manner with respect to the vehicle body. Under such a mounted state, a shared support load of the power unit is exerted on the mount 10, and the first mounting bracket 12 and the second mounting bracket 14 are displaced toward each other, and the main rubber elastic body 16 is elastically deformed. The main vibration to be vibration-proofed is input in the vertical direction in FIG. 1 which is the mount axis direction. In the following description, the vertical direction refers to the vertical direction in FIG. 1 unless otherwise specified.

  More specifically, the first mounting member 12 has a substantially truncated cone shape that protrudes downward, and is provided with a screw hole 18 at the center thereof. The first mounting member 12 is fixed to the power unit by being bolted to a power unit-side mounting member (not shown) via a fixing bolt screwed into the screw hole 18.

  On the other hand, the second mounting bracket 14 has a large-diameter, generally cylindrical shape. The second mounting bracket 14 is press-fitted into the cylindrical mounting bracket 20 on the vehicle body side, and the plurality of leg portions 22 fixed to the bracket 20 are fixed to the vehicle body side member with bolts or the like, The second mounting bracket 14 is fixed to the vehicle body.

  The first mounting bracket 12 is spaced from the opening side of one of the second mounting brackets 14 (upper in FIG. 1), and the central axes of the first mounting bracket 12 and the second mounting bracket 14 are substantially the same. It is located on the same line. 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 large truncated cone shape. The first mounting bracket 12 is vulcanized and bonded to the end surface on the small diameter side of the main rubber elastic body 16 in a state of being inserted in the axial direction. On the outer peripheral surface of the large-diameter side end portion of the main rubber elastic body 16, the inner peripheral surface from the upper end portion in the axial direction of the second mounting member 14 to the intermediate portion in the axial direction is overlapped and vulcanized and bonded. In short, 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, thereby the first mounting bracket 12 and the second mounting bracket 14. The metal fittings 14 are elastically connected to each other by the main rubber elastic body 16, and one opening (upper in FIG. 1) of the second mounting metal fitting 14 is covered with the main rubber elastic body 16 in a fluid-tight manner. . A thin seal rubber layer 24 integrally formed with the main rubber elastic body 16 is attached to the inner peripheral surface of the second mounting bracket 14 from the axially intermediate portion to the lower end portion in the axial direction. Furthermore, a substantially inverted mortar-shaped circular recess 26 is formed on the large-diameter side end surface of the main rubber elastic body 16, thereby reducing the tensile stress of the main rubber elastic body 16 due to the shared support load of the power unit. Yes.

  In addition, a diaphragm 28 as a flexible film is disposed in the other opening (lower in FIG. 1) of the second mounting bracket 14. The diaphragm 28 is easily deformed by exhibiting a disk shape made of a thin rubber film with a slack, and a large-diameter ring-shaped fixing bracket 30 is vulcanized and bonded to the outer peripheral edge. Yes. The fixing bracket 30 is inserted into the second mounting bracket 14, and the second mounting bracket 14 is subjected to diameter reduction processing such as drawing. Thus, the diaphragm 28 is fixed to the second mounting bracket 14, and the other opening of the second mounting bracket 14 is covered with the diaphragm 28 in a fluid-tight manner.

  Further, a partition member 32 is accommodated between the main rubber elastic body 16 and the diaphragm 28 inside the second mounting bracket 14. As shown in FIGS. 2 and 3, the partition member 32 has a thick and substantially disk shape as a whole, and is formed using a hard synthetic resin material, a metal material, or the like. The partition member 32 is inserted from the opening of the other (lower in FIG. 1) of the second mounting bracket 14 together with the diaphragm 28, and the second mounting bracket 14 is subjected to diameter reduction processing. The second mounting bracket 14 is fixed in a form extending in a direction perpendicular to the axis at the center portion in the axial direction.

  On one side (upper side in FIG. 1) sandwiching the partition member 32 inside the second mounting bracket 14, a part of the wall portion is constituted by the main rubber elastic body 16, and the elasticity of the main rubber elastic body 16. A pressure receiving chamber 34 is formed in which pressure fluctuation is caused based on the deformation. Further, on the other side (lower side in FIG. 1) sandwiching the partition member 32 inside the second mounting bracket 14, a part of the wall portion is constituted by the diaphragm 28, and based on the elastic deformation of the diaphragm 28. An equilibrium chamber 36 is formed in which volume changes are easily allowed. The pressure receiving chamber 34 and the equilibrium chamber 36 are filled with an incompressible fluid. As the sealing fluid, for example, water, alkylene glycol, polyalkylene glycol, silicone oil, or the like is employed. In order to effectively obtain a vibration-proofing effect based on the resonance action of the fluid, a low-viscosity fluid of 0.1 Pa · s or less Is preferably employed. As is clear from this, the hard partition member 32 fixedly supported by the second mounting bracket 14 is provided between the pressure receiving chamber 34 and the equilibrium chamber 36, in other words, between the main rubber elastic body 16 and the diaphragm 28. It is arrange | positioned between opposing surfaces.

  In addition, a recess 38 is formed in the central portion of the partition member 32 so as to open in one axial direction (downward in FIG. A stepped portion 40 is formed at an axially intermediate portion of the recess 38, and the opening 42 of the recess 38 has a larger diameter than the bottom wall portion 44 across the stepped portion 40. An annular fitting groove 46 is formed on the outer peripheral portion of the stepped portion 40. Further, the opening 42 of the recess 38 is formed with a fitting opening 48 having a diameter larger than that of the opening 42 and opening at one end face in the axial direction of the partition member 32.

  Furthermore, the partition member 32 is provided with a rubber elastic plate 50 as a movable plate. The rubber elastic plate 50 has a thin and substantially disk shape and is made of a rubber elastic body. The spring rigidity of the rubber elastic plate 50 is made smaller than that of the main rubber elastic body 16 and larger than that of the diaphragm 28. In addition, annular elastic protrusions 52 and 52 that protrude on both sides in the axial direction are integrally formed on the outer peripheral edge of the rubber elastic plate 50. The rubber elastic plate 50 is fitted into the opening 42 of the recess 38 of the partition member 32, and the outer peripheral edge of the rubber elastic plate 50 is closely adhered to the opening 42 of the recess 38, and the rubber. One elastic projection 52 in the axial direction of the elastic plate 50 (upper in FIG. 1) is fitted into the fitting groove 46 of the stepped portion 40 of the recess 38 by being elastically deformed.

  Furthermore, a ring-shaped fitting member 54 is fitted and fixed to the fitting port 48 of the partition member 32. The upper end portion of the fitting member 54 is integrally formed with a flange that extends inward in the direction perpendicular to the axis, and the flange has an annular fitting groove 56 that opens in one axial direction (upward in FIG. 1). Is formed. When the fitting member 54 is fixed to the partition member 32, the elastic protrusion 52 on the other axial direction (lower side in FIG. 1) of the rubber elastic plate 50 is fitted into the fitting groove 56 by being elastically deformed.

  Thereby, the outer peripheral edge of the rubber elastic plate 50 is fixed to the opening 42 of the recess 38 of the partition member 32, and the portion excluding the outer peripheral edge of the rubber elastic plate 50 is arranged on the partition member 32 so as to be elastically deformable. The rubber elastic plate 50 covers the opening 42 of the recess 38 in a fluid-tight manner. An incompressible fluid is sealed in the recess 38 covered with the rubber elastic plate 50 in the same manner as the pressure receiving chamber 34 and the equilibrium chamber 36, and the bottom wall portion 44 and the peripheral wall portion of the recess 38, rubber elasticity An intermediate chamber 58 having a wall portion including the plate 50 is formed. An intermediate chamber 58 and an equilibrium chamber 36 are formed on both sides of the rubber elastic plate 50.

  In short, the pressure receiving chamber 34 is formed on one side (the upper side in FIG. 1) sandwiching the intermediate chamber 58, and the equilibrium chamber 36 is located on the other side (the lower side in FIG. 1) across the intermediate chamber 58. Is formed. A partition wall partitioning the pressure receiving chamber 34 and the intermediate chamber 58 includes the bottom wall portion 44 of the recess 38. Further, the main displacement or deformation direction of the rubber elastic plate 50 is the vertical direction in FIG. 1 which is the mount axis direction.

  Further, the outer peripheral portion of the intermediate portion in the axial direction of the partition member 32 and the outer peripheral portion of one axial direction (downward in FIG. 1) are respectively opened outward in the direction perpendicular to the axis, and are, for example, slightly shorter in the circumferential direction. The peripheral grooves extending in the circumferential direction are connected to each other by connecting one end of each peripheral groove to each other, so that the outer periphery of the partition member 32 as a whole extends in the circumferential direction with a length of less than two rounds. A groove 60 is formed. Furthermore, a second circumferential groove 62 that opens outward in the direction perpendicular to the axis and extends, for example, with a length of a little less than one round in the circumferential direction, is provided on the outer circumferential portion of the other axial direction (upper in FIG. 1) of the partition member 32. Is formed. In addition, the first circumferential groove 60 and the second circumferential groove 62 are partitioned with respect to the partition member 32 by partitioning one end of each of the grooves 60 and 62 with the barrier portion 64 interposed therebetween. They are formed independently and arranged in parallel with each other. Furthermore, the partition member 32 is fixed to the second mounting bracket 14, and the outer peripheral surface of the partition member 32 is closely adhered to the inner peripheral surface of the second mounting bracket 14 via the seal rubber layer 24. The respective openings that open outward in the direction perpendicular to the axis of the first circumferential groove 60 and the second circumferential groove 62 are covered with the second mounting bracket 14 in a fluid-tight manner.

  A first orifice passage 66 is constituted by the first circumferential groove 60 covered with the second mounting bracket 14. One end of the first orifice passage 66 is connected to the pressure receiving chamber 34 through a notch-shaped first communication window 68 formed at one end (upper in FIG. 1) in the axial direction of the partition member 32. In addition, the other end of the first orifice passage 66 is connected to the equilibrium chamber 36 through a notch-like communication port 70 formed at the other end (downward in FIG. 1) of the partition member 32 in the axial direction. Has been. Thereby, the pressure receiving chamber 34 and the equilibrium chamber 36 are communicated with each other through the first orifice passage 66. The second orifice passage 72 is constituted by the second circumferential groove 62 covered with the second mounting bracket 14. One end portion of the second orifice passage 72 is formed in a portion different from the first communication window 68 at one end portion in the axial direction of the partition member 32 through a notch-shaped second communication window 74. 34, and the other end of the second orifice passage 72 is connected to the intermediate chamber 58 through a communication hole 76 penetrating the peripheral wall of the recess 38 of the partition member 32. Thereby, the pressure receiving chamber 34 and the intermediate chamber 58 are communicated with each other through the second orifice passage 72. In short, in the present embodiment, the first orifice passage 66 and the second orifice passage 72 are formed using the outer peripheral portion of the partition member 32.

  In the present embodiment, the resonance frequency of the fluid that flows through the first orifice passage 66 based on the relative pressure fluctuation generated between the pressure receiving chamber 34 and the equilibrium chamber 36 at the time of vibration input is, for example, about 10 Hz. The engine shake is tuned so as to advantageously exhibit an anti-vibration effect (high damping characteristic) based on a resonance action of a fluid with respect to an engine shake having a low frequency and a large amplitude. Further, the resonance frequency of the fluid that flows through the second orifice passage 72 based on the relative pressure fluctuation generated between the pressure receiving chamber 34 and the intermediate chamber 58 at the time of vibration input is, for example, a high frequency of about 15 to 30 Hz. It is tuned so as to advantageously exhibit an anti-vibration effect (low dynamic spring characteristic) based on the resonance action of the fluid with respect to small amplitude idling vibration. Note that the tuning of the first orifice passage 66 and the second orifice passage 72 is performed by, for example, the rigidity of the wall springs of the pressure receiving chamber 34, the equilibrium chamber 36, and the intermediate chamber 58 (the amount of pressure change necessary for changing the unit volume). The pressure fluctuation transmitted through the orifice passages 66 and 72 is generally adjusted by adjusting the passage length and the passage sectional area of each orifice passage 66 and 72 in consideration of the characteristic value corresponding to Can be grasped as the tuning frequency of the orifice passages 66 and 72.

  Therefore, a substantially circular fitting hole 78 penetrates in the thickness direction (up and down in FIG. 1) in the central portion of the bottom wall portion 44 of the recess 38 constituting a part of the wall portion of the intermediate chamber 58. It is installed. A rubber pressure adjusting plate 80 as a pressure adjusting plate is disposed in the fitting hole 78.

  The rubber pressure adjusting plate 80 has a substantially circular shape with a small diameter, and is formed using a rubber elastic body. The spring stiffness of the rubber pressure plate 80 is made smaller than that of the main rubber elastic body 16 and larger than that of the rubber elastic plate 50. The outer diameter of the rubber pressure adjusting plate 80 is larger than the diameter of the fitting hole 78. In addition, a fitting groove 82 that extends continuously in the circumferential direction with a substantially constant concave cross section that opens radially outward (left and right in FIG. 1) is provided in the axially intermediate portion of the outer peripheral surface of the rubber pressure adjusting plate 80. Is formed.

  The rubber pressure adjusting plate 80 is overlapped with the bottom wall portion 44 around the fitting hole 78 of the partition member 32 and pushed into the fitting hole 78, whereby the outer peripheral portion of the rubber pressure adjusting plate 80 is elastically deformed. Then, the edge of the fitting hole 78 is fitted into the fitting groove 82. Thereby, the rubber pressure adjusting plate 80 is disposed on the bottom wall portion 44 of the partition member 32, covers the fitting hole 78 in a fluid-tight manner, and one surface (upper in FIG. 1) of the rubber pressure adjusting plate 80 is In addition to being in contact with the pressure receiving chamber 34, the other surface (lower in FIG. 1) of the rubber pressure adjusting plate 80 is in contact with the intermediate chamber 58. In other words, the rubber pressure adjusting plate 80 is disposed on the bottom wall portion 44 of the partition member 32 that partitions the pressure receiving chamber 34 and the intermediate chamber 58, and the rubber pressure adjusting plate 80 is set to a relative pressure difference between the pressure receiving chamber 34 and the intermediate chamber 58. Based on this, it is elastically deformed.

  In the automobile engine mount 10 having such a structure, when a low-frequency large-amplitude shake vibration is input between the first mounting bracket 12 and the second mounting bracket 14, it is caused in the pressure receiving chamber 34. Based on the pressure fluctuation, a fluid action such as a resonance action of the fluid caused to flow between the pressure receiving chamber 34 and the equilibrium chamber 36 through the first orifice passage 66 is generated.

  In particular, in the present embodiment, the spring stiffness of the rubber pressure plate 80 facing the pressure receiving chamber 34 is made larger than the spring stiffness of the rubber elastic plate 50, and a direct pressure regulating action between the pressure receiving chamber 34 and the intermediate chamber 58 is achieved. Thus, the wall spring rigidity of the intermediate chamber 58 with respect to the amplitude of the shake vibration is sufficiently increased. Thus, the pressure fluctuation in the pressure receiving chamber 34 is suppressed from being absorbed by the rubber pressure adjusting plate 80 when the shake vibration is input, and a sufficient fluid flow amount through the first orifice passage 66 is ensured. As a result, the vibration damping effect can be advantageously exhibited based on the flow action such as the resonance action of the fluid through the first orifice passage 66.

  Further, when high-frequency and small-amplitude idling vibration is input between the first mounting bracket 12 and the second mounting bracket 14, the flow resistance of the first orifice passage 66 is remarkably increased and substantially blocked. Based on the relative pressure difference between the pressure receiving chamber 34 and the intermediate chamber 58, a fluid action such as a resonance action of the fluid is caused through the second orifice passage 72. In particular, since the spring stiffness of the rubber pressure plate 80 is greater than the spring stiffness of the rubber elastic plate 50, the rubber pressure plate 80 is prevented from being greatly deformed when idling vibration is input, and the pressure in the pressure receiving chamber 34 is reduced. The fluctuation is effectively induced, and the volume change of the intermediate chamber 58 is easily allowed by the hydraulic pressure absorbing action of the rubber elastic plate 50. Accordingly, a relative pressure fluctuation is effectively induced between the pressure receiving chamber 34 and the intermediate chamber 58, and a sufficient fluid flow amount through the second orifice passage 72 is ensured between the chambers 34 and 58. Thereby, the vibration insulation effect by the fluid flow action through the second orifice passage 72 can be advantageously exhibited.

  By the way, for example, when an automobile travels on a wavy road with large irregularities, when an amplitude fluctuation larger than idling vibration is input in a higher frequency range than the resonance frequency of the first orifice passage 66, rubber elasticity The plate 50 is positively or greatly elastically deformed, and a large negative pressure may be locally generated in the intermediate chamber 58 due to a pressure fluctuation exerted on the intermediate chamber 58 by the elastic deformation of the rubber elastic plate 50. There is.

  In this case, another portion different from the rubber elastic plate 50 that constitutes a part of the wall portion of the intermediate chamber 58 is formed of the rubber pressure adjusting plate 80, so that the elastic deformation of the rubber elastic plate 50 causes the intermediate chamber 58 to move into the intermediate chamber 58. The applied pressure fluctuation is absorbed by the elastic deformation of the rubber pressure adjusting plate 80. In particular, since the spring stiffness of the rubber pressure plate 80 is greater than that of the rubber elastic plate 50, the rubber pressure plate 80 is more than the rubber elastic plate 50 when an amplitude vibration larger than the idling vibration is input. Large elastic deformation is suppressed, and generation of an excessive negative pressure in the intermediate chamber 58 due to large deformation of the rubber pressure adjusting plate 80 is suppressed. As a result, the large decompression state of the intermediate chamber 58 due to the elastic deformation of the rubber elastic plate 50 is eliminated, and the generation of cavitation bubbles is reduced or avoided.

  When an amplitude vibration larger than the idling vibration is input in a frequency range lower than the resonance frequency of the first orifice passage 66, the pressure fluctuation induced in the pressure receiving chamber 34 is balanced through the first orifice passage 66. Since the air is released into the chamber 36, it is possible to avoid an excessive negative pressure from being generated in the intermediate chamber 58.

  Therefore, in the automobile engine mount 10 according to the present embodiment, a part of the wall portion of the intermediate chamber 58 includes the rubber elastic plate 50 and the rubber pressure adjusting plate 80 having the structure as illustrated. The intermediate chamber 58 is considered to be a cause of the generation of cavitation bubbles generated in the intermediate chamber 58 while sufficiently maintaining the vibration-proofing effect based on the fluid action of each fluid through the first and second orifice passages 66 and 72. The depressurized state is avoided, and the shocking noise and vibration that have been a problem can be effectively suppressed.

  By the way, with respect to the engine mount 10 according to the present embodiment, the vibration isolation characteristics were measured in order to confirm the effect of reducing shocking abnormal noise and vibration. That is, in the state where an initial load corresponding to the shared support load of the power unit is applied to the mount 10, an amplitude vibration larger than the idling vibration in a frequency region higher than the resonance frequency of the first orifice passage 66 is applied to the load input direction of the mount 10. The load transmitted to the second mounting bracket 14 is applied to the second mounting bracket 14 when the first mounting bracket 12 is oscillated and displaced in the axial direction (up and down in FIG. 1). Measured with an attached acceleration sensor.

  As a result, in the engine mount 10 having the structure according to the present embodiment, an engine mount having a comparative structure prepared for characteristic comparison, in which the bottom wall portion of the partition member is a rigid wall without using a rubber pressure adjusting plate. Compared to the above, it was confirmed that the transmission power of high-frequency components can be suppressed. Also from this fact, the structure according to the present invention in which the rubber pressure adjusting plate 80 is disposed in the partition wall partitioning the pressure receiving chamber 34 and the intermediate chamber 58, the vibration isolating characteristic at the time of shock load input in the conventional vibration isolator. The technical effect of the present invention that the above problem can be effectively solved will be understood.

  As mentioned above, although one embodiment of the present invention has been described in detail, this is merely an example, and the present invention is not limited to any specific description by this embodiment, and is based on the knowledge of those skilled in the art. The present invention can be implemented in a mode with various changes, corrections, improvements, and the like. Further, it goes without saying that such embodiments are all included in the scope of the present invention without departing from the gist of the present invention.

  For example, the shape, size, structure, number, arrangement, and the like of the rubber elastic plate 50 and the rubber pressure adjusting plate 80 are not limited to those illustrated.

  In the above-described embodiment, the rubber elastic plate 50 and the rubber pressure adjusting plate 80 are each disposed on the substantially central axis of the mount 10. Two or more may be provided.

  Further, in the above-described embodiment, the edge of the fitting hole 78 is fitted into the fitting groove 82 of the rubber pressure adjusting plate 80, whereby the rubber pressure adjusting plate 80 separates the pressure receiving chamber 34 and the intermediate chamber 58 from the bottom wall of the partition member 32. For example, a ring-shaped fitting member is fixed to the outer peripheral edge portion of the rubber pressure adjusting plate, and the fitting member is fixed to the edge of the fitting hole. Similar to the structure in which the rubber elastic plate 50 is fixed to the partition member 32, the outer peripheral edge portion of the rubber pressure adjusting plate is sandwiched and held between the stepped portion provided on the partition member 32 and the fitting member. It is also possible to dispose a rubber pressure adjusting plate on the bottom wall portion.

  Further, the shapes of the partition member 32, the first and second orifice passages 66, 72, and the like such as shape, size, structure, number, and arrangement are not limited to those illustrated. For example, in the above-described embodiment, the first orifice passage 66 and the second orifice passage 72 are configured by the first circumferential groove 60 and the second circumferential groove 62 that are independently formed with respect to the partition member 32. Are provided in parallel with each other, but one end of each of the first circumferential groove and the second circumferential groove is connected to each other, and the first orifice passage is connected to the first and second orifices. It is also possible to provide the first orifice passage and the second orifice passage in series with each other by including the circumferential groove and configuring the second orifice passage including the second circumferential groove. .

  Further, in the engine mount 10 according to the embodiment, the rubber pressure adjusting plate 80, the intermediate chamber 58, and the rubber elastic plate 50 are included, and fluid flows and transmits pressure along with the elastic deformation of the rubber pressure adjusting plate 80 and the rubber elastic plate 50. By configuring the fluid flow path and tuning the resonance frequency of the fluid flow path to a higher frequency range than the resonance frequency of the second orifice passage 72, a vibration isolation effect corresponding to the vibration in the high frequency range is obtained. It is also possible.

  Further, the present invention provides a shaft as a first mounting member that is employed as an engine mount, a suspension bush or the like for an FF type automobile as described in, for example, Japanese Patent Laid-Open No. 2-243030. A large-diameter cylindrical outer cylinder member as a second mounting member is spaced apart outwardly in the direction perpendicular to the axis of the member, and the main rubber elastic body is interposed between the axially perpendicular surfaces of the shaft member and the outer cylinder member. It is also applicable to a cylindrical vibration isolator in which a shaft member and an outer cylinder member are connected by a main rubber elastic body.

FIG. 3 is a longitudinal cross-sectional explanatory view showing an automobile engine mount as one embodiment of the present invention, corresponding to the II cross section of FIG. 2. It is a plane explanatory view showing a partition member which constitutes a part of the engine mount for automobiles in FIG. It is one side explanatory drawing which shows the partition member in FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Engine mount for motor vehicles, 12 ... 1st mounting bracket, 14 ... 2nd mounting bracket, 16 ... Main body rubber elastic body, 34 ... Pressure-receiving chamber, 36 ... Equilibrium chamber, 44 ... Bottom wall part, 50 ... Rubber elasticity Plate 58, intermediate chamber 66, first orifice passage 72, second orifice passage 80, rubber pressure plate

Claims (4)

The first attachment member attached to one member to be vibration-proof connected and the second attachment member attached to the other member to be vibration-proof connected are separated from each other and connected by the main rubber elastic body, and the wall portion Forming a pressure receiving chamber, part of which is made of the main rubber elastic body, an equilibrium chamber, part of which is made of a flexible film, and an intermediate chamber, part of which is made of a movable plate. Then, the intermediate chamber and the equilibrium chamber are arranged on both sides of the movable plate, an incompressible fluid is sealed in the pressure receiving chamber, the equilibrium chamber, and the intermediate chamber, and the pressure receiving chamber and the equilibrium chamber are further connected. The resonance frequency of the fluid that allows the fluid to be communicated with each other and the fluid that is allowed to flow inside is tuned to the engine shake, and the fluid pressure that allows the pressure receiving chamber and the intermediate chamber to communicate with each other and fluid is allowed to flow inside Has idling vibration In-tuning are fluid-filled engine mount forming a second orifice passages,
While the movable plate is constituted by a plate-like body made of a rubber elastic body, a pressure adjusting plate made of a plate-like body made of a rubber elastic body is disposed on a partition wall partitioning the pressure receiving chamber and the intermediate chamber, and A fluid-filled engine mount, wherein the spring stiffness of the pressure adjusting plate is larger than the spring stiffness of the movable plate.   A fluid flow path that includes the movable plate, the pressure adjustment plate, and the intermediate chamber and that is configured to fluidly flow and transmit pressure along with the elastic deformation of the movable plate and the pressure adjustment plate is configured. 2. The fluid-filled engine mount according to claim 1, wherein the resonance frequency is tuned to a higher frequency range than the resonance frequency of the second orifice passage.   A hard partition member fixedly supported by the second mounting member is disposed between the pressure receiving chamber and the equilibrium chamber, and opens toward the equilibrium chamber at a central portion of the partition member. The intermediate chamber is formed by fluidly covering the opening of the recess with the movable plate, and the partition wall portion is configured by the bottom wall portion of the recess, The fluid-filled engine mount according to claim 1 or 2, wherein the first orifice passage and the second orifice passage are formed by using an outer peripheral portion of a partition member.   The second mounting member is formed in a cylindrical shape, the first mounting member is spaced from one opening side of the second mounting member, and the first mounting member and the second mounting member are arranged By connecting with the main rubber elastic body, one opening of the second mounting member is fluid-tightly closed, while the other opening of the second mounting member is covered with the flexible film. The fluid-filled engine mount according to claim 3, wherein the partition member is fitted into the second mounting member and disposed between the opposing surfaces of the main rubber elastic body and the flexible membrane.

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