JP4937207B2 - Fluid filled vibration isolator - Google Patents

Description

The present invention relates to an anti-vibration device used as, for example, an automobile engine mount and the like, and in particular, a fluid-filled vibration-proof vibration device that obtains a vibration-proof effect by utilizing the flow action of an incompressible fluid sealed inside. It relates to the device.

  Conventionally, a fluid-filled vibration isolator has been known as a type of anti-vibration coupling body and anti-vibration support body mounted between members constituting a vibration transmission system. It is being considered. Such a fluid-filled vibration isolator is generally a pressure receiving chamber in which a first mounting member and a second mounting member are connected by a main rubber elastic body, and a part of the wall portion is configured by the main rubber elastic body. In addition, an equilibrium chamber in which a part of the wall portion is formed of a flexible film is provided, and an incompressible fluid is sealed in the pressure receiving chamber and the equilibrium chamber. The pressure receiving chamber and the equilibrium chamber are communicated with each other based on a relative pressure fluctuation caused between the pressure receiving chamber and the equilibrium chamber when vibration is input between the first mounting member and the second mounting member. The vibration isolating effect can be exhibited based on the resonance action of the fluid that can flow through the orifice passage formed as described above.

  By the way, in an automobile engine mount, low-frequency vibration such as engine shake is likely to be a problem when the vehicle is running, whereas high-frequency vibration such as idling vibration is likely to be a problem when the vehicle is stopped. Since a plurality of vibrations in different frequency ranges are input, there may be a case where anti-vibration performance is required for each of the plurality of vibrations in different frequency ranges.

  However, in a fluid-filled vibration isolator equipped with an orifice passage, the orifice passage becomes substantially closed due to vibration at a frequency higher than the tuning frequency of the orifice passage, resulting in a significant increase in dynamic spring. Therefore, the vibration-proofing effect based on the resonance action of the fluid is difficult to be effectively exhibited only in a narrow frequency range in which the orifice passage is tuned.

  In order to cope with such a problem, for example, in Patent Document 1, a plurality of orifice passages tuned to different frequency ranges are provided, and the plurality of orifice passages are subjected to input vibration by an actuator such as a negative pressure type or an electromagnetic type. There has been proposed a structure in which the function is switched according to the frequency. However, since the structure described in Patent Document 1 requires a special actuator that requires supply of external energy such as negative pressure or electric power for operation, connection to a negative pressure source, a power source, or the like of the actuator is not possible. In addition to the necessity, a control device for controlling the operation is also required, resulting in a problem that the number of parts is extremely increased, the structure and control are complicated, and the manufacturing cost is increased.

  Therefore, Patent Document 2 proposes a structure for opening and closing switching valves of a plurality of orifice passages by utilizing the difference in amplitude of input vibration. However, such a fluid-filled vibration isolator is also complicated in structure and difficult to manufacture. Moreover, even if the plunger is driven by the pressure accumulating mechanism at the time of large amplitude vibration input to operate the switching valve of the orifice passage, it is difficult to selectively express the complete open state and the complete closed state, and the input vibration The switching operation of the anti-vibration characteristic is likely to be unstable depending on the state or the like, and it is difficult to stably switch the target anti-vibration characteristic. In combination with the complicated structure, there are problems in reliability and durability, and there are difficulties in practical use.

Japanese Patent Laid-Open No. 5-118375 International Publication No. 2004/081408 Pamphlet

  Here, the present invention has been made in the background as described above, and the problem to be solved is to use a simple actuator without using an actuator that requires supply of external energy such as air pressure or electric power. With a small number of parts in the configuration, it is possible to demonstrate an excellent vibration isolation effect based on the fluid flow action of the orifice passage with respect to vibrations in a plurality of different frequency ranges with high operational reliability, and a novel and highly practical An object of the present invention is to provide a fluid-filled vibration isolator having a simple structure.

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

  That is, the feature of the first aspect of the present invention is that (a) a first attachment member attached to one member to be vibration-proof connected, and (b) attached to the other member to be vibration-proof connected. A second mounting member, (c) a main rubber elastic body that elastically connects the first mounting member and the second mounting member, and (d) a part of the wall portion by the main rubber elastic body. And a pressure receiving chamber filled with an incompressible fluid, and (e) a part of the wall portion is made of a flexible membrane so that the volume is variable. An equilibrium chamber in which an incompressible fluid is sealed, (f) an intermediate chamber in which a part of the wall portion is formed of an elastic partition wall and in which the incompressible fluid is sealed, (g) the pressure receiving chamber, A first fluid flow path communicating with the intermediate chamber; (h) a second fluid flow path communicating with the equilibrium chamber and the intermediate chamber; A working air chamber formed on the opposite side of the intermediate chamber across the elastic partition; and (j) allowing air to be discharged from the working air chamber to the external space, but flowing into the working air chamber from the external space And (k) a tuning frequency region in which the working air chamber communicates with an external space, and a vibration isolation effect is exerted by a fluid action of fluid that flows through the second fluid flow path. In the vibration input state, only an insufficient air inflow is allowed to recover the amount of air discharged from the working air chamber through the one-way valve. In the non-input state of the vibration in the tuning frequency range, the elastic partition wall is allowed. The fluid-filled vibration isolator includes a micro intake hole that allows sufficient air inflow to restore the initial volume of the working air chamber based on the elasticity of the working air chamber.

  In the fluid-filled vibration isolator having the structure according to this aspect, for example, the tuning frequency region where the vibration isolating effect due to the fluid action of the fluid that is caused to flow through the second fluid flow path is exhibited is a low frequency large frequency such as an engine shake. Set to amplitude vibration. When such low-frequency large-amplitude vibration is input, the positive pressure generated in the pressure receiving chamber is applied to the intermediate chamber and the elastic partition through the first fluid flow path. Accordingly, the elastic partition wall is brought close to the opposing wall surface of the working air chamber, and the air in the working air chamber is discharged to the external space through the one-way valve.

  The elastic partition wall tries to recover to the initial state before the vibration input by its elasticity, but the inflow of air into the working air chamber is blocked by the one-way valve and the air through the minute air intake hole. The amount of inflow is the amount of air discharged from the working air chamber through the one-way valve in the input state of the vibration in the tuning frequency range where the anti-vibration effect due to the fluid action of the fluid flowing through the second fluid flow path is exhibited. Only an insufficient amount of air is allowed to recover. Accordingly, the rapid recovery of the working air chamber to the initial volume before the vibration input is limited, and the next positive pressure due to the vibration is input to the elastic partition wall before the recovery to the initial state before the vibration input. As a result, the elastic partition is maintained in a restrained state in which recovery to the initial state is limited, and the wall spring rigidity is increased.

  As a result, the change in volume of the intermediate chamber is limited when low frequency large amplitude vibration is input. Accordingly, a relative pressure fluctuation is effectively generated between the pressure receiving chamber and the equilibrium chamber, and the amount of fluid flowing through the second fluid channel can be effectively ensured. As a result, an anti-vibration effect is effectively exhibited by the fluid action of the fluid that is caused to flow through the second fluid channel against low-frequency large-amplitude vibration such as engine shake.

  On the other hand, in the non-input state of vibration in the tuning frequency range where the anti-vibration effect is exerted by the fluid action of the fluid flowing through the second fluid flow path, for example, in the non-input state of the engine shake, high frequency such as idling vibration When a small amplitude vibration is input, the amount of air flowing in through the minute air intake holes is allowed to be sufficient to restore the initial volume of the working air chamber based on the elasticity of the elastic partition wall. . As a result, recovery based on the elasticity of the elastic partition wall, that is, a change in the volume of the intermediate chamber is allowed, and a relative pressure fluctuation between the pressure receiving chamber and the intermediate chamber is effectively induced. The amount of fluid flowing through the first fluid flow path communicating with each other is effectively ensured. As a result, an anti-vibration effect based on the flow action of the fluid flowing through the first fluid flow path is effectively exhibited against high-frequency small-amplitude vibration such as idling vibration.

  In the present invention, the fluid that is caused to flow through the second fluid flow path only needs to include at least the second fluid flow path on the flow path, for example, only the second fluid flow path. The pressure receiving chamber and the equilibrium chamber are made to flow not only through the intermediate chamber and the equilibrium chamber, but also through the first fluid channel and the second fluid channel and through the intermediate chamber. It may be a fluid that flows between the two. In short, in the present invention, the high-frequency orifice passage may be formed only by the first fluid flow path, and the low-frequency orifice passage may be formed by only the second fluid flow path. The high-frequency orifice passage may be constituted by only one fluid flow path, and the low-frequency orifice passage may be constituted by cooperation of the first fluid flow path and the second fluid flow path. Further, for example, when the first fluid flow path has a large diameter such as traveling noise and a short flow path length, etc., the pressure receiving chamber and the intermediate chamber to which the elastic partition is constrained as a whole are one pressure receiving chamber (expanded pressure receiving chamber). It can be understood that the low-frequency orifice passage is configured by the resonance action of the fluid through the second fluid flow path between the expanded pressure receiving chamber and the equilibrium chamber.

  Thereby, in the fluid filled type vibration isolator having the structure according to this aspect, a plurality of components with a simple configuration and a small number of parts can be provided without providing an actuator or the like that requires supply of external energy such as air pressure or electric power. Any vibrations in different frequency regions can exhibit an excellent vibration isolation effect based on the fluid flow action of the orifice passage.

  In particular, according to this aspect, since the configuration is simple, it is possible to realize the switching operation of the anti-vibration characteristic according to the input vibration in different frequency regions with high reliability and durability, and excellent practical use. It is possible to provide a fluid-filled vibration isolator having a property.

  According to a second aspect of the present invention, in the fluid-filled vibration isolator according to the first aspect, an inner surface facing the elastic partition wall is caused to flow through the second fluid channel in the working air chamber. The elastic partition wall as the volume of the working air chamber decreases due to the air being discharged from the working air chamber through the one-way valve with vibration input in a tuning frequency range that exhibits a vibration isolation effect due to the fluid flow action. It is characterized by being made into the contact surface with which at least one part of is contact | abutted.

  According to this aspect, the restraint state of the elastic partition wall can be maintained more firmly by bringing the elastic partition wall into contact with the contact surface. As a result, the volume change of the intermediate chamber can be more firmly restricted, and the amount of fluid flowing through the second fluid flow path can be more stably ensured.

  According to a third aspect of the present invention, in the fluid filled type vibration damping device according to the first or second aspect, the elastic partition wall defining the working air chamber swells in a substantially dome shape toward the intermediate chamber. In addition to the curved convex shape, the opposing inner surface of the working air chamber facing the elastic partition is a curved concave shape that is recessed toward the opposite side of the elastic partition.

  According to this aspect, at the time of inputting low-frequency large-amplitude vibration such as an engine shake, for example, the elastic partition wall can be deformed into a convex shape toward the opposed inner surface on the working air chamber side. As a result, the shape of the elastic partition wall is such that the working air chamber is filled with air and the convex shape to the intermediate chamber in the state where the working air chamber exists, and the air in the working air chamber is discharged and the working air chamber disappears. It can be clearly different from the concave shape to the intermediate chamber in the squeezed state. At the same time, when the elastic partition wall is protruded toward the facing surface of the working air chamber, the facing surface of the working air chamber is formed in a curved concave shape substantially corresponding to the elastic partition wall, so that the elastic partition wall is It becomes easy to restrain in a wide range easily and constraining the opposing surface. On the other hand, when air is allowed to flow into the working air chamber and the elastic partition wall is restored to the initial state, the elastic partition wall is positively used so that the elastic partition wall becomes a convex shape in the intermediate chamber. It can be restored. As a result, switching to the vibration-proof state based on the resonant action of the fluid that can flow through the second fluid flow path in a state where the working air chamber has disappeared can be realized with higher reliability and reliability. I can do it.

  According to a fourth aspect of the present invention, there is provided the fluid filled type vibration damping device according to any one of the first to third aspects, wherein the minute intake hole is made to flow through the first fluid flow path. The inflow of air sufficient to recover the amount of air discharged from the working air chamber through the one-way valve in the input state of the vibration in the tuning frequency range where the vibration isolation effect due to the fluid action is exhibited is allowed. , Feature.

  According to this aspect, for example, the tuning frequency range in which the vibration isolating effect due to the fluid action of the fluid that is caused to flow through the first fluid flow path is exhibited is set to the high frequency small amplitude vibration such as the idling vibration. In this case, since the air intake sufficient to recover the amount of air discharged from the working air chamber through the one-way valve by the input of the high-frequency small-amplitude vibration applied by the minute air intake hole is allowed, the elastic partition wall is placed in the intermediate chamber. Before the next positive pressure is generated, recovery to an initial state or a state close to that under a static pressure state can be allowed. As a result, when vibration in the tuning frequency range of the first fluid flow path is input, the volume change of the intermediate chamber is stably generated, and the relative pressure fluctuation between the pressure receiving chamber and the intermediate chamber is effective. Therefore, the flow amount of the fluid flowing through the first fluid flow path communicating with the pressure receiving chamber and the intermediate chamber can be effectively ensured. As a result, the anti-vibration effect based on the flow action of the fluid flowing through the first fluid channel can be more stably and effectively exhibited. In short, according to this aspect, in the non-input state of the vibration at the tuning frequency of the second fluid flow path, the elastic partition is allowed to recover quickly, particularly when the vibration in the tuning frequency range of the first fluid flow path is input. As a result, the anti-vibration effect by the first fluid channel can be more effectively exhibited together with the anti-vibration effect by the second fluid channel.

  According to a fifth aspect of the present invention, in the fluid-filled vibration isolator according to any one of the first to fourth aspects, in the one-way valve, the positive pressure from the working air chamber becomes a predetermined value. It is characterized in that a preload for maintaining the closed state is set.

  According to this aspect, for example, the tuning frequency region in which the vibration isolation effect due to the fluid action of the fluid that is caused to flow through the first fluid flow path is set to high frequency small amplitude vibration such as idling vibration, and such high frequency small amplitude When vibration is input, it is possible to prevent air from being discharged from the working air chamber through the one-way valve. As a result, the working air chamber is substantially sealed when such high-frequency small-amplitude vibration is input, so that the volume change of the intermediate chamber and the bulging deformation of the elastic partition wall are caused based on the compressibility of the working air chamber. Permissible. As a result, the pressure fluctuation in the pressure receiving chamber is absorbed and reduced by the working air chamber due to the elastic deformation of the elastic partition wall. Thereby, the low dynamic spring effect by the high frequency orifice channel | path comprised by the 1st fluid flow path is exhibited.

  The setting of the preload in this aspect can be performed by, for example, a check valve, and a structure in which a valve that opens in one direction is biased in a closing direction by a biasing means such as a coil spring or rubber is adopted. obtain.

  According to a sixth aspect of the present invention, in the fluid-filled vibration isolator according to any one of the first to fifth aspects, the second attachment member includes a cylindrical portion, and the cylindrical portion One opening portion side of the cylindrical portion is closed by the main rubber elastic body that is disposed on one opening portion side of the first body and that connects the first mounting member and the second mounting member. On the other hand, the other opening of the cylindrical portion is closed with the flexible membrane, and an incompressible fluid sealing region is provided between the opposing surfaces of the main rubber elastic body and the flexible membrane. And a partition member is disposed between the opposing surfaces of the main rubber elastic body and the flexible membrane and supported by the cylindrical portion, and between the partition member and the main rubber elastic body. The pressure receiving chamber is formed at the same time, and the equilibrium chamber is formed between the partition member and the flexible membrane. , Said said intermediate chamber inside the partition member air chamber is formed, characterized.

  According to this aspect, the pressure receiving chamber and the equilibrium chamber, and the working air chamber and the intermediate chamber can be configured compactly in the cylindrical portion. In this aspect, more preferably, the outer peripheral surface of the partition member is exposed to the external space, and the air supply / exhaust passage communicating the working air chamber and the external space is connected to the outer space from the outer peripheral surface of the partition member. The embodiment taken out in the above can be adopted. In this way, a communication structure with the external space of the working air chamber can be realized more easily.

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

  First, FIG. 1 shows an automobile engine mount 10 as an embodiment of a fluid filled type vibration damping device according to the present invention. The engine mount 10 has a structure in which a first mounting bracket 12 as a first mounting member and a second mounting bracket 14 as a second mounting member are elastically connected by a main rubber elastic body 16. The first mounting bracket 12 is mounted on the power unit side, while the second mounting bracket 14 is mounted on the vehicle body side, so that the power unit is supported in an anti-vibration manner with respect to the body.

  FIG. 1 shows a state in which the engine mount 10 is not attached to the automobile. However, in this embodiment, the shared support load of the power unit is input in the mount axis direction (up and down in FIG. 1) in the attached state. Is done. Therefore, in the mounted state, the main vibration to be vibrated is input substantially in the mount axis direction, and the first mounting bracket 12 and the second mounting bracket 14 are pivoted based on the elastic deformation of the main rubber elastic body 16. It will be displaced in the direction which mutually approaches in a direction. In the following description, the vertical direction means the vertical direction in FIG. 1 unless otherwise specified.

  More specifically, the first mounting bracket 12 has a nut portion 17 having a substantially cylindrical shape with a small diameter, and a screw hole 18 that opens upward is formed in the central portion of the nut portion 17. Yes. The fixing bolt 20 is screwed into the screw hole 18 so as to protrude upward. Further, a contact portion 22 that protrudes radially outward is integrally formed at the lower end portion of the nut portion 17.

  Further, a bound stopper rubber 23 is provided on the nut portion 17 of the first mounting bracket 12. The bound stopper rubber 23 has a substantially bottomed cylindrical shape that opens downward. Further, a substantially cylindrical insertion portion 25 extending in the opening direction is integrally formed at the center of the upper bottom portion of the bound stopper rubber 23, and the bound stopper rubber 23 is penetrated in the axial direction by the insertion portion 25. The insertion portion 25 is extrapolated from above with respect to the nut portion 17 of the first mounting bracket 12, so that the bound stopper rubber 23 opens downward and is attached to the first mounting bracket 12.

  On the other hand, the second mounting bracket 14 has a large-diameter substantially stepped cylindrical shape, and the upper portion is a large-diameter cylindrical portion 26 with a stepped portion 24 formed at an axially intermediate portion therebetween. On the other hand, the lower portion is a small-diameter cylindrical portion 28 having a smaller diameter than the large-diameter cylindrical portion 26. The large-diameter cylindrical portion 26 and the small-diameter cylindrical portion 28 constitute a cylindrical portion of the second mounting bracket 14. Further, the first mounting bracket 12 is spaced apart from the opening side of one of the second mounting brackets 14 (upward in FIG. 1), and the central axes of both the brackets 12 and 14 are positioned substantially on the same line. The 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-diameter, generally frustoconical shape, and its end surface on the small-diameter side embeds substantially the entire contact portion 22 of the first mounting bracket 12 so that the nut portion 17 is positioned upward. The first mounting bracket 12 is vulcanized and bonded to the outer peripheral surface of the first mounting bracket 12 in a state where the first mounting bracket 12 is projected. Further, the outer peripheral surface of the large-diameter side end portion of the main rubber elastic body 16 is vulcanized and bonded to the inner peripheral surface of the large-diameter cylindrical portion 26 and the step portion 24 of the second mounting bracket 14. Thereby, 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. The first mounting bracket 12 and the second mounting bracket 14 are elastically connected to each other by the main rubber elastic body 16 and one side of the second mounting bracket 14 on the large-diameter cylindrical portion 26 side ( The upper opening in FIG. 1 is fluid-tightly closed by the main rubber elastic body 16. A large mortar-shaped recess 30 having a substantially mortar shape that opens downward is formed on the large-diameter side end face of the main rubber elastic body 16. Further, the main rubber elastic body 16 is wound around the contact portion 22 of the first mounting bracket 12, and a stopper rubber 31 formed integrally with the main rubber elastic body 16 is located above the outer peripheral portion of the contact portion 22. It is formed to extend. Furthermore, a thin sealing rubber layer 32 integrally formed with the main rubber elastic body 16 is formed on the inner peripheral surface of the small diameter cylindrical portion 28 of the second mounting bracket 14 with a substantially constant thickness. It is deposited. A positioning step 33 that slightly protrudes inward in the radial direction is formed at the upper end portion of the seal rubber layer 32.

  Further, in the integrally vulcanized molded product of the main rubber elastic body 16 provided with the first and second mounting brackets 12 and 14, from the other opening side of the second mounting bracket 14 (downward in FIG. 1). A partition member 34 is assembled. The partition member 34 is a divided structure formed by combining a plurality of members. In particular, in this embodiment, the partition member 34 includes an upper partition member 36 and a lower partition member 38.

  The upper partition member 36 has a generally cup shape that opens downward as a whole, and the overall outer diameter dimension is smaller than the inner diameter dimension of the small-diameter cylindrical portion 28 of the second mounting bracket 14. The upper partition member 36 is formed using a hard synthetic resin material in the present embodiment. The upper partition member 36 is formed with a large-diameter central recess 40 that opens in the center of the lower surface as a recess. The inner peripheral surface of the peripheral wall portion of the central recess 40 has an axial direction (depth direction). ), An annular stepped portion 42 is formed extending outward in the direction perpendicular to the axis. As a result, the center recess 40 has an inner diameter dimension on the upper bottom side (upper side in FIG. 1) sandwiching the stepped portion 42, and an inner diameter dimension on the opening side (lower side in FIG. 1) sandwiching the stepped portion 42. Has been smaller than. Furthermore, a locking step 43 that extends in the direction perpendicular to the axis is formed on the outer peripheral surface of the upper end of the peripheral wall of the upper partition member 36. The lower end surface of the outer peripheral portion around the opening of the central recess 40 in the upper partition member 36 is a flat surface that extends in the direction perpendicular to the axis.

  Further, in the central portion of the upper bottom portion of the upper partition member 36, a first series passage 44 is formed as a first fluid channel that penetrates the upper bottom portion in the thickness direction (vertical direction in FIG. 1). . One end portion of the first series passage 44 is opened at the upper end surface of the upper partition member 36, and the other end portion is opened at the central recess 40 of the upper partition member 36. In particular, in the present embodiment, the opening to the central recess 40 of the first series passage 44 is opposed to the central portion of the movable rubber film 68 described later in the axial direction. As will be described later, the first series passage 44 is a fluid flow path used as an orifice passage, and FIG. 1 is merely a model diagram, and the length and cross-sectional area of the first series passage 44 are required. It can be set as appropriate in consideration of anti-vibration characteristics and the like.

  Further, in the peripheral wall portion of the upper partition member 36, a second communication passage 46 is formed as a second fluid flow path extending in the thickness direction of the upper partition member 36 (vertical direction in FIG. 1). One end of the second communication passage 46 is opened above the stepped portion 42 on the inner surface of the peripheral wall portion of the central recess 40 of the upper partition member 36, and the other end is connected to the upper partition member 36. It is opened at the lower end surface. As will be described later, the second communication passage 46 is a fluid flow path used as an orifice passage. FIG. 1 is merely a model diagram, and the length and cross-sectional area of the second communication passage 46 are required. It can be set as appropriate in consideration of anti-vibration characteristics and the like. For example, the second communication passage 46 may be a communication hole extending in a predetermined length such as a little less than two in the circumferential direction of the upper partition member 36.

  A lower partition member 38 is superimposed on the upper partition member 36 from below in the axial direction. The lower partition member 38 has a thick, substantially disk shape having substantially the same outer dimensions as the upper partition member 36, and is formed using a hard synthetic resin material. The lower partition member 38 is formed with a lower recess 48 that opens to the center of the lower surface. In addition, a shallow dish-shaped central protrusion 50 is integrally formed at the center of the upper end portion of the lower partition member 38.

  On the outer peripheral surface on the base end side of the central protrusion 50, a fitting groove 52 extending in the circumferential direction over the entire circumference is formed. Further, a communication hole 54 penetrating in the axial direction is formed in the outer peripheral portion of the lower partition member 38 at a position corresponding to the opening of the second communication passage 46 of the upper partition member 36 when the upper partition member 36 is overlaid. Is formed. The communication holes 54 are opened on the upper end surface of the lower partition member 38 and the inner surface of the lower recess 48 on both sides in the axial direction.

  Further, a concave groove-like upper fitting groove 56 extending continuously over substantially the entire circumference in the circumferential direction is formed at the upper end in the axial direction on the outer peripheral surface of the lower partition member 38. On the other hand, at the lower end in the axial direction on the outer peripheral surface of the lower partition member 34, a lower fitting groove 58 having a concave groove shape extending continuously over the entire circumference is formed.

  Further, a contact surface 60 having a curved surface shape that is concave toward the upper side in the axial direction of the lower partition member 38 is formed on the upper end surface of the central protrusion 50. The contact surface 60 has a substantially circular shape when viewed from above, and particularly in this embodiment, the contact surface 60 is a curved surface having a substantially constant curvature over the entire surface.

  An air passage 62 is opened at one place on the outer periphery of the contact surface 60. The air passage 62 is formed in the outer peripheral portion of the contact surface 60 so as to extend in the substantially axial direction inside the lower partition member 38, and one end portion is opened to the contact surface 60, while the other The end portion is communicated with a port portion 64 opened on the outer peripheral surface of the lower partition member 38. The port portion 64 is formed so as to project in a cylindrical shape in a circular recess opened on the outer peripheral surface at the lower end portion in the axial direction of the lower partition member 38.

  A partition wall member 66 is disposed above the lower partition member 38 so as to cover the central protrusion 50. The partition member 66 is configured by vulcanizing and bonding a fitting ring 70 to an outer peripheral edge portion of a movable rubber film 68 as an elastic partition wall.

  The movable rubber film 68 has a generally disc shape as a whole, and has a tapered shape which is slightly positioned so as to be gradually positioned upward in the radial direction toward the center in the radial direction. The outer peripheral edge of the movable rubber film 68 is attached to the inner peripheral surface of the fitting ring 70 having a substantially annular shape. As a specific shape of the movable rubber film 68, for example, a shape as disclosed in Japanese Patent Application Laid-Open No. 2008-32055 can be suitably employed.

  The inner peripheral surface of the fitting ring 70 is attached to the outer peripheral edge portion of the movable rubber film 68 having such a shape. The fitting ring 70 has a thin, substantially cylindrical shape, and is formed of a metal material such as iron or an aluminum alloy. A locking projection 72 that extends radially inward over the entire circumference is integrally formed at one end (downward in this embodiment) of the fitting ring 70 in the axial direction.

  Further, a seal lip 74 that protrudes upward in the axial direction is formed on the upper end portion in the axial direction of the fitting ring 70. The seal lip 74 is formed integrally with the movable rubber film 68, and is continuously formed in the circumferential direction with a substantially constant chevron cross-sectional shape over the entire circumference.

  The axially lower end portion of the fitting ring 70 in the partition member 66 having such a structure is extrapolated to the central protrusion 50 of the lower partitioning member 38, and the lower portion of the fitting ring 70 from the axially intermediate portion. On the other hand, the locking protrusion 72 is locked and fixed to the fitting groove 52 of the central protrusion 50 by performing diameter reduction processing such as an eight-way drawing. Thereby, the upper part of the opening of the central protrusion 50 is fluid-tightly covered with the movable rubber film 68, and the entire contact surface 60 is opposed to the movable rubber film 68, which is the bottom of the central protrusion 50. A working air chamber 76 is formed between the contact surface 60 and the movable rubber film 68. Here, since the working air chamber 76 has a part of the wall portion made of the movable rubber film 68, a predetermined volume is set by the elasticity of the movable rubber film 68, and the movable rubber film 68 is elastic. A predetermined volume is ensured under static pressure by being held away from the contact surface 60 of the working air chamber 76.

  Further, the upper partition member 36 is overlaid on the upper surface of the lower partition member 38, so that the fitting ring 70 is fitted into the central recess 40 of the upper partition member 36. The upper end portion of the fitting ring 70 presses the seal lip 74 against the step portion 42 of the central recess 40 in the axial direction. Thus, the gap between the fitting ring 70 and the upper partition member 36 is fluid-tightly sealed in the axial direction by the seal lip 74 over the entire circumference. Although not apparent from the drawings, the upper partition member 36 and the lower partition member 38 are assembled to each other by engaging the engagement pieces formed on the opposing surfaces with the engagement grooves. ing.

  Thus, the partition member 34 configured to include the upper partition member 36 and the lower partition member 38 thus overlapped in the axial direction is inserted into the small diameter cylindrical portion 28 of the second mounting bracket 14 from below. It is done. Then, the locking step 43 formed on the outer peripheral surface of the upper partition member 36 is superimposed on the positioning step 33 formed on the seal rubber layer 32, so that the upper partition member 36 and the lower partition member 38 are It is positioned in the axial direction with respect to the second mounting bracket 14. In this positioning state, the lower partitioning member 38 is in a state where only the upper part from the central protrusion 50 is fitted into the second mounting member 14, and the recess in which the port portion 64 is formed is The second mounting bracket 14 is exposed to the external space so as to protrude outward in the direction perpendicular to the axis.

  Then, by reducing the diameter of the small-diameter cylindrical portion 28 of the second mounting bracket 14 such as eight-way drawing, the outer peripheral surfaces of the upper and lower partition members 36 and 38 are the inner peripheral surfaces of the small-diameter cylindrical portion 28. A fitting protrusion that is fluid-tightly superimposed on the inner peripheral surface of the small-diameter cylindrical portion 28 via a seal rubber layer 32 that is attached to the cylindrical portion 28 and that extends radially inward at the lower end edge of the small-diameter cylindrical portion 28. 78 is fitted into the upper fitting groove 56 of the lower partitioning member 38 and locked. As a result, the partition member 34 is supported by the small-diameter cylindrical portion 28 in the second mounting bracket 14 and is fitted and fixed to the second mounting bracket 14.

  Furthermore, one end of an air pipe 80 formed using a synthetic resin material is connected to the port portion 64 exposed to the external space of the second mounting bracket 14 in an extrapolated state. The air duct 80 extends from the partition member 34 to the external space.

  A one-way valve 82 is provided at the end of the air pipe 80 opposite to the end connected to the port 64. As the one-way valve 82, a conventionally known structure can be appropriately employed. FIG. 2 schematically illustrates the one-way valve 82 in the present embodiment. In the present embodiment, the inner diameter of the end portion of the air duct 80 on the side opposite to the port portion 64 is expanded on the opening end surface 86 side with the stepped surface 84 interposed therebetween. Further, the opening on the side opposite to the port portion 64 in the air duct 80 is covered by a cover member 88 being superimposed on the opening end surface 86, and through a plurality of vent holes 90 penetrating the cover member 88. The interior of the air duct 80 is communicated with the external space.

  A sealing body 92 made of, for example, a metal sphere is disposed in the housing space formed between the stepped surface 84 and the lid member 88 in a housed state, and the sealing body 92 and the lid member. A coil spring 94 is interposed between the coil springs 88 in a compressed state. As a result, the sealing body 92 is urged toward the stepped surface 84 by the coil spring 94 to hold the intermediate opening 96 opened in the stepped surface 84 in a closed state. Accordingly, the discharge of air from the working air chamber 76 to the outside space through the one-way valve 82 is allowed, but the inflow of air from the outside space through the one-way valve 82 into the working air chamber 76 is prevented. . In particular, the one-way valve 82 in this embodiment is pre-set by a coil spring 94 and is kept closed until the positive pressure from the working air chamber 76 to which the air pipe 80 is connected reaches a predetermined value. It has come to be.

  Further, a minute intake hole 98 is formed between the one-way valve 82 and the port portion 64 in the air pipe 80. The minute air intake hole 98 is formed as a communication hole penetrating the air duct 80 and communicating the internal space of the air duct 80 with the external space. Thus, the working air chamber 76 is communicated with the external space of the engine mount 10 through the minute intake holes 98.

  Here, the inflow amount of air allowed by the minute intake holes 98 is a working air chamber in an input state of a vibration in a tuning frequency range in which a vibration isolating effect due to a fluid action of fluid flowing through the second communication passage 46 is exhibited. Only an inflow of air that is insufficient to recover the amount of air discharged from the one-way valve 82 from 76 is allowed, and in a non-input state of vibration in such a tuning frequency region, the working air is based on the elasticity of the movable rubber film 68. It is set to allow sufficient air inflow to restore the initial volume of chamber 76. In particular, in the present embodiment, it is sufficient to restore the initial volume of the working air chamber 76 in the input state of the vibration of the tuning frequency at which the vibration isolating effect due to the fluid action of the fluid flowing through the first series passage 44 is exhibited. It is set to allow air inflow.

  That is, particularly in the present embodiment, as will be described later, the tuning frequency region in which the vibration isolation effect due to the fluid action of the fluid flowing through the second communication passage 46 is exhibited is set to a low frequency large amplitude vibration such as an engine shake. In addition, the tuning frequency range in which the anti-vibration effect due to the fluid action of the fluid that is caused to flow through the first series passage 44 is set to a high-frequency large-amplitude vibration such as idling vibration. Therefore, in the present embodiment, the one-way valve 82 and the minute intake hole 98 have an exhaust amount from the one-way valve 82 larger than an inflow amount from the minute intake hole 98 in an engine shake input state, and an idling vibration input state. Below, the preload and the exhaust amount of the one-way valve 82 and the air inflow amount of the minute intake hole 98 are adjusted so that the inflow amount from the minute intake hole 98 exceeds the exhaust amount from the one-way valve 82.

  In short, the micro air intake hole 98 in the present embodiment exhibits an inflow resistance larger than the discharge flow resistance of the one-way valve 82 when low frequency large amplitude vibration such as engine shake is input. Is input, the amount of air discharged from the one-way valve 82 on the plus side of the internal pressure is required to be sufficiently high in resistance to be sucked on the minus side of the pressure. On the other hand, when high-frequency small-amplitude vibration such as idling vibration is input, an inflow resistance smaller than the discharge flow resistance of the one-way valve 82 is exhibited. The discharged air amount is sucked on the negative pressure side to exhibit a low inflow resistance sufficient to restore the volume of the working air chamber 76.

  The discharge flow resistance of the one-way valve 82 and the inflow resistance of the minute intake hole 98 are adjusted by, for example, adjusting the urging force of the coil spring 94 in the one-way valve 82 and the opening area of the intermediate opening 96. This is possible by adjusting the length and shape of the intake hole 98, the opening area, and the like. In addition, the minute intake hole 98 can be prevented from clogging by adopting a relatively large opening area by increasing the length or bending it to increase the loss, thereby preventing clogging. If the length cannot be secured sufficiently, the opening area may be reduced correspondingly.

  On the other hand, a diaphragm 100 as a flexible film is assembled to the lower end portion of the lower partition member 38 exposed from the second mounting bracket 14. Diaphragm 100 is formed of a thin, substantially disk-shaped rubber elastic film that is easily deformed by having a sufficient slack in the center portion.

  A large-diameter cylindrical fixing fitting 102 is vulcanized and bonded to the outer peripheral edge portion (in the present embodiment, the outer peripheral surface) of the diaphragm 100. A fitting protrusion 104 extending in a flange shape radially inward is formed integrally with the upper end opening of the fixture 102. In addition, a thin seal rubber layer integrally formed with the diaphragm 100 is formed on the inner peripheral surface of the fixing bracket 102, and the diaphragm 100 extends downward from the fixing bracket 102.

  Then, the fixing bracket 102 is extrapolated to the lower partition member 38 from below in the axial direction, and thereafter, the fixing bracket 102 is subjected to diameter reduction processing. As a result, the inner peripheral surface of the upper end portion of the fixing metal fitting 102 is protruded outwardly in the axial direction from the second attachment metal member 14 via the seal rubber layer. , Downward) is fixedly fitted on the outer peripheral surface of the end portion. Then, the fitting protrusion 104 of the fixing metal fitting 102 is fitted into the lower fitting groove 58 of the lower partition member 38 and locked.

  Thereby, the opening of the lower recess 48 of the lower partition member 38 is covered with the diaphragm 100 in a fluid-tight manner, and the other (downward in FIG. 1) of the second mounting bracket 14 on the small-diameter cylindrical portion 28 side. The opening is closed fluid-tight with the diaphragm 100. Further, the partition member 34 is disposed between the axially opposed surfaces of the main rubber elastic body 16 and the diaphragm 100.

  Here, between the opposing surfaces of the main rubber elastic body 16 and the diaphragm 100, a fluid chamber 106 is formed as an incompressible fluid sealing region that is sealed with respect to the external space. Incompressible fluid is enclosed. As the incompressible fluid sealed in the fluid chamber 106, for example, water, alkylene glycol, polyalkylene glycol, silicone oil, or the like is adopted. Particularly, the anti-vibration effect based on the fluid action such as the resonance action of the fluid is used. In order to obtain it effectively, it is desirable to employ a low viscosity fluid of 0.1 Pa · s or less.

  The incompressible fluid is sealed in the fluid chamber 106, for example, in a state where the upper partition member 36 and the lower partition member 38 are assembled in the atmosphere and the port portion 64 of the partition member 34 is sealed with a stopper. After assembling the integrally vulcanized molded product of the main rubber elastic body 16 having the first and second mounting brackets 12 and 14, the integrally vulcanized molded product of the diaphragm 100 and the partition member 34 in an incompressible fluid. This is advantageously realized by removing the plug of the port portion 64.

  Furthermore, the fluid chamber 106 is vertically divided into two in the axial direction by disposing the partition member 34 so as to expand in the direction perpendicular to the axis. Between the partition member 34 and the main rubber elastic body 16, a part of the wall portion is constituted by the main rubber elastic body 16, and vibration between the first mounting bracket 12 and the second mounting bracket 14 is performed. A pressure receiving chamber 108 is formed in which pressure fluctuation is generated based on elastic deformation of the main rubber elastic body 16 at the time of input. On the other hand, between the partition member 34 and the diaphragm 100, a part of the wall portion is constituted by the diaphragm 100, and an equilibrium chamber 110 in which a volume change is easily allowed based on elastic deformation of the diaphragm 100 is formed. . The pressure receiving chamber 108 and the equilibrium chamber 110 are filled with an incompressible fluid.

  Further, two internal spaces are formed in the partition member 34 by partitioning an internal space formed between the upper partition member 36 and the lower partition member 38 with a movable rubber film 68. The internal space formed between the upper partition member 36 and the movable rubber film 68 is an intermediate chamber 112 in which a part of the wall is formed of the movable rubber film 68, while the lower partition member 38 An internal space formed between the movable rubber films 68 is a working air chamber 76 in which a part of the wall is formed of the movable rubber film 68. Thus, the intermediate chamber 112 is formed above the movable rubber film 68 and the working air chamber 76 is formed below the partition member 34.

  As described above, in the engine mount 10 according to the present embodiment, the equilibrium chamber 110 is formed on the opposite side of the pressure receiving chamber 108 with the intermediate chamber 112 interposed therebetween, and the working air chamber 76 includes the intermediate chamber 112 and the equilibrium chamber 110. Is formed between. The intermediate chamber 112 is filled with an incompressible fluid, like the pressure receiving chamber 108 and the equilibrium chamber 110.

  Here, the pressure receiving chamber 108 and the intermediate chamber 112 are communicated with each other through a first series passage 44 formed in the upper partition member 36, while the intermediate chamber 112 and the equilibrium chamber 110 are formed in the upper partition member 36. The second communication passage 46 and the lower partition member 38 are connected to each other through a communication hole 54. Particularly in the present embodiment, the first orifice passage 114 is formed by the first series passage 44, and fluid flow through the first orifice passage 114 is allowed between the pressure receiving chamber 108 and the intermediate chamber 112. On the other hand, the second series passage 44 and the second communication passage 46 cooperate to form a second orifice passage 116, and the intermediate chamber is formed between the pressure receiving chamber 108 and the equilibrium chamber 110. Fluid flow through the second orifice passage 116 via 112 is permitted.

  In this embodiment, the resonance frequency of the fluid that flows through the first orifice passage 114 formed by the first series passage 44 is about 20 to 40 Hz corresponding to idling vibration or the like based on the resonance action of the fluid. It is tuned to exhibit an effective anti-vibration effect (vibration insulation effect by a low dynamic spring) against vibrations in the high frequency range. Further, the resonance frequency of the fluid flowing through the second orifice passage 116 formed by the cooperation of the first series passage 44 and the second communication passage 46 corresponds to an engine shake or the like based on the resonance action of the fluid. It is tuned so as to exhibit an effective anti-vibration effect (high damping effect) against low-frequency vibrations around 10 Hz.

  The tuning of the first and second orifice passages 114 and 116 is necessary, for example, to change the rigidity of the wall springs of the pressure receiving chamber 108, the equilibrium chamber 110, and the intermediate chamber 112, that is, their fluid chambers by a unit volume. The passage length and passage cross-sectional area of each of the orifice passages 114 and 116 are adjusted in consideration of characteristic values based on the elastic deformation amounts of the main rubber elastic body 16, the diaphragm 100, and the movable rubber film 68 corresponding to various pressure changes. In general, the frequency at which the phase of the pressure fluctuation transmitted through the orifice passages 114 and 116 changes to a substantially resonant state is grasped as the tuning frequency of the orifice passages 114 and 116. I can do it.

  In the engine mount 10 having such a structure, the nut portion 17 of the first mounting bracket 12 is screwed and fixed to the mounting member on the power unit side using the fixing bolt 20, and the second mounting bracket 14 The large diameter cylindrical portion 26 is fixed to the outer bracket 118.

  The outer bracket 118 has a substantially stepped cylindrical shape, and the upper part sandwiching the step part 120 spreading in an annular shape in the direction perpendicular to the axis is the small diameter cylindrical part 122 and the lower part is from the small diameter cylindrical part 122. Is also a large diameter cylindrical portion 124. Further, an inner flange-shaped stopper portion 125 is integrally formed in the opening portion of the small diameter cylindrical portion 122. Further, a plurality of downwardly extending legs 126 are fixed to the outer peripheral surface of the large diameter cylindrical portion 124, and a bolt insertion hole 128 is provided through the bottom of the legs 126.

  Then, the second mounting bracket 14 is inserted from below the outer bracket 118, and the stepped portion 120 of the outer bracket 118 is overlaid on the upper end surface of the large-diameter cylindrical portion 26 of the second mounting bracket 14, The second mounting bracket 14 is positioned with respect to the outer bracket 118, and the large diameter cylindrical portion 26 of the second mounting bracket 14 is press-fitted and fixed to the large diameter cylindrical portion 124 of the outer bracket 118. In such a fixed state, the stopper rubber 125 integrally formed with the stopper portion 125 of the outer bracket 118 and the main rubber elastic body 16 is opposed to each other with a predetermined distance in the axial direction. Thus, when vibration in the rebound direction in which the first mounting bracket 12 and the second mounting bracket 14 are separated from each other is input between both the brackets 12, 14, the first mounting bracket 12 and the stopper portion 125 are By abutting through the stopper rubber 31, the displacement in the rebound direction of the first mounting bracket 12 and the second mounting bracket 14 is limited in a buffering manner.

  The bound stopper rubber 23 provided on the first mounting bracket 12 is a nut of the first mounting bracket 12 that is protruded from the outer bracket 118 after the second mounting bracket 14 is press-fitted and fixed to the outer bracket 118. The part 17 is attached by being extrapolated from above. Further, under the assembled state of the outer bracket 118, the port portion 64 of the partition member 34 is positioned below the lower end edge portion of the outer bracket 118, and the air duct 80 connected to the port portion 64. The extension of the engine mount 10 to the outside is not hindered by the outer bracket 118.

  Then, the leg 126 of the outer bracket 118 fixed to the second mounting bracket 14 is fixed to a mounting member on the vehicle body side (not shown) with a bolt or the like using the bolt insertion hole 128. As a result, the engine mount 10 is mounted between the power unit and the vehicle body so that the power unit is supported on the vehicle body in a vibration-proof manner.

  In the engine mount 10 having such a structure, when a low-frequency large-amplitude vibration such as an engine shake is input, a pressure fluctuation with a large amplitude is induced in the pressure receiving chamber 108. Such large amplitude pressure fluctuation is applied to the intermediate chamber 112 through the first series passage 44. In the present embodiment, the first orifice passage 114 is formed by the first series passage 44, but as described above, the tuning frequency of the first orifice passage 114 is in a high frequency range such as idling vibration. Since it is set and excluded from a low frequency region such as an engine shake, the anti-vibration effect by the first orifice passage 114 is not exhibited when low frequency vibration is input.

  Then, a positive pressure having a large amplitude is induced in the intermediate chamber 112, so that the movable rubber film 68 is brought close to the contact surface 60. Particularly in the present embodiment, since the opening of the first series passage 44 is positioned on the central axis of the movable rubber film 68, the pressure fluctuation in the pressure receiving chamber 108 can be more effectively applied to the movable rubber film 68. It is possible to influence. Thereby, the air in the working air chamber 76 is discharged to the external space through the air pipe 80 and the one-way valve 82, and the volume of the working air chamber 76 is reduced. Here, the movable rubber film 68 tries to recover to an initial state (an attempt to move away from the contact surface 60) by the negative pressure induced in the intermediate chamber 112 by vibration input or its own elasticity, but it is in the working air chamber 76. Inflow of air into the air pipe 80 is blocked by a one-way valve 82 provided at the end of the air pipe 80, and the amount of air inflow through the minute air intake holes 98 is changed between the first series passage 44 and the second communication passage. 46 is discharged from the working air chamber 76 through the one-way valve 82 under an input state of low-frequency large-amplitude vibration such as engine shake in which the vibration-proofing effect is exerted by the second orifice passage 116 formed in cooperation. Insufficient air volume is allowed to recover.

  Therefore, under the input state of such low frequency large amplitude vibration, the movable rubber film 68 is subjected to the next positive pressure by the vibration input before returning to the initial state, and the movable rubber film 68 is in contact with the contact surface. It is restrained in the state where it is made to approach 60. Particularly in this embodiment, when a large positive pressure is exerted on the movable rubber film 68, the movable rubber film 68 is in contact with the contact surface 60 as the volume of the working air chamber 76 decreases. Be bound. Further, particularly in the present embodiment, the movable rubber film 68 is inverted into a curved shape that is convex toward the contact surface 60, and the curved concave shape in which the contact surface 60 is recessed on the opposite side of the movable rubber film 68. Therefore, the inverted movable rubber film 68 can be easily adhered to the contact surface 60 in a wide range, and can be restrained more firmly. As a result, the working air chamber 76 is substantially eliminated when the low-frequency large-amplitude vibration is input.

  As a result, the volume change of the intermediate chamber 112 is limited by increasing the rigidity of the wall spring of the movable rubber film 68, and the pressure variation in the pressure receiving chamber 108 is suppressed from being absorbed by the intermediate chamber 112. Relative pressure fluctuations between 108 and the equilibrium chamber 110 are effectively produced. Thereby, the flow amount of the fluid flowing through the second orifice passage 116 can be effectively ensured, and the flow of the fluid flowing through the second orifice passage 116 with respect to the low-frequency large-amplitude vibration such as engine shake. The anti-vibration effect (high attenuation effect) due to the action is effectively exhibited.

  On the other hand, when high frequency small amplitude vibration such as idling vibration is input, the movable rubber film 68 is deformed based on the pressure fluctuation of the pressure receiving chamber 108, and the air in the working air chamber 76 passes through the one-way valve 82. Although it is discharged outside, the amplitude of the movable rubber film 68 is small because the amplitude of the input vibration is small. Therefore, the amount of air discharged from the working air chamber 76 is relatively small, and an amount sufficient to restore the initial volume of the working air chamber 76 is allowed as the amount of air flowing in through the minute intake holes 98. As a result, the elastic deformation of the movable rubber film 68 is allowed at the time of vibration input, and a relative pressure fluctuation between the pressure receiving chamber 108 and the intermediate chamber 112 is effectively induced. Thereby, the flow amount of the fluid that flows through the first orifice passage 114 can be effectively ensured, and the fluid flow action of the fluid that flows through the first orifice passage 114 against high-frequency small-amplitude vibration such as idling vibration. The anti-vibration effect (low dynamic spring effect) is effectively exhibited.

  As described above, according to the present embodiment, all of the vibrations in a plurality of different frequency ranges are effective with a simple configuration without providing an actuator that requires supply of external energy such as air pressure or electric power. Can exhibit excellent anti-vibration effect.

  In particular, in the present embodiment, the movable rubber film 68 has a substantially dome shape that protrudes toward the intermediate chamber 112 under static pressure, so that the convex shape in the state where the working air chamber 76 exists is The shape can be clearly changed to the concave shape in the state in which the working air chamber 76 is eliminated, and the vibration isolation effect by the first orifice passage 114 and the vibration isolation effect by the second orifice passage 116 Can be switched more reliably and with high reliability.

  FIG. 3 shows an example of an engine mount structured according to the first embodiment, and a comparative example of an engine mount that performs switching operation of an orifice passage using a negative pressure source according to the conventional structure described in Patent Document 1. FIG. 3 (a) shows the results of measuring the attenuation coefficient when vibrations having an amplitude of ± 1 mm are input with different frequencies, and FIG. 3 (b) shows the comparative example. As is apparent from FIG. 3, according to the present embodiment, it was confirmed that a high attenuation effect substantially equal to that of the comparative example of the conventional structure can be obtained in a frequency range around 10 Hz corresponding to engine shake.

  FIG. 4 shows an example of an engine mount having a structure according to the first embodiment, and a comparative example of an engine mount for switching an orifice passage using a negative pressure source in accordance with the conventional structure described in Patent Document 1. As a result of measuring dynamic spring constants when vibrations having an amplitude of ± 0.05 mm are input with different frequencies, FIG. 4A shows the results of the examples, and FIG. 4B shows the comparative examples. Show. As is apparent from FIG. 4, according to the present embodiment, it is confirmed that the low dynamic spring effect substantially equal to that of the comparative example of the conventional structure can be obtained in the frequency range of about 20 Hz to 40 Hz corresponding to idling vibration. It was.

  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, as described above, the specific shapes of the first fluid channel and the second fluid channel can be appropriately set by those skilled in the art depending on the required vibration isolation performance. In the first embodiment, the second communication passage 46 is formed in the outer circumferential surface of the upper partition member 36 to form a circumferential groove extending in a predetermined length in the circumferential direction, and the opening of the circumferential groove is formed as a seal rubber layer. It may be formed by covering with 32.

  In the embodiment, the first orifice passage 114 for high frequency is formed using the first series passage 44 and the first series passage 44 and the second communication passage 46 are used to form the first low-frequency first passage. Although the two orifice passages 116 are formed, for example, the second orifice passage 116 for low frequency may be formed using only the second communication passage 46. In such a case, for example, the opening size of the first series passage 44 may be made larger and tuned so as to exhibit an anti-vibration effect against higher-frequency vibrations such as running-up noise. When the rubber film 68 is constrained, the pressure receiving chamber 108 and the intermediate chamber 112 function as a single pressure receiving chamber (extended pressure receiving chamber) as a whole, and the second pressure passage 46 and the equilibrium chamber 110 are connected through the second communication passage 46. The low-frequency orifice passage may be configured by the fluid flow action. As is clear from this, the tuning frequency of the plurality of orifice passages constituted by each of the first fluid passage and the second fluid passage or a combination thereof is not limited, for example, an engine shake, It is tuned to match the vibration required by the vehicle, such as idling vibration and running noise.

  In the above embodiment, air is discharged from the working air chamber through the one-way valve even when high-frequency small-amplitude vibration such as idling vibration is input. By adjusting the preload, air may be prevented from being discharged from the working air chamber when a small amplitude vibration such as idling vibration is input. In such a case, the volume change of the intermediate chamber and the bulging deformation of the elastic partition wall are allowed based on the compressibility of the working air chamber, and the pressure fluctuation of the pressure receiving chamber is caused by the elastic deformation of the elastic partition wall. Absorption is reduced by the working air chamber. Thereby, the low dynamic spring effect by the orifice channel | path comprised with a 1st fluid flow path may be exhibited.

  Furthermore, as the one-way valve, various conventionally known structures can be appropriately employed. For example, FIGS. 5 and 6 each show one-way valves 130 and 132 in different modes in a model manner. In the one-way valve 130, a plate-shaped sealing rubber plate 134 having an area larger than the opening size of the intermediate opening 96 is urged by a leaf spring 136 whose one end is fixed to the step surface 84. The intermediate opening 96 is held in a closed state by being pressed against the opening 96, and a preload is applied by the urging force of the leaf spring 136. Thus, the biasing means for setting the preload on the one-way valve is not limited to the coil spring. Furthermore, more simply, for example, a part of the outer peripheral portion of the plate-shaped sealing rubber plate 138 is fixed to the stepped surface 84 by adhesion or the like as in the one-way valve 132 shown in model in FIG. The intermediate opening 96 may be held closed by the elastic force of the rubber stopper plate 138 itself.

  Further, in the present invention, a known structure that has been conventionally used in a fluid-filled vibration isolator can be appropriately employed. For example, as described in Japanese Patent Application Laid-Open No. 2008-32055, the upper side In the partition member 36, a movable plate or a movable film is provided in a partition wall partitioning the pressure receiving chamber 108 and the intermediate chamber 112 to suppress a high dynamic spring against a vibration in a higher frequency region such as a traveling boom noise and further improve the vibration proof performance. Improvements may be made.

  Needless to say, the specific shapes of the first mounting member, the second mounting member, and the main rubber elastic body connecting them are not limited at all. For example, Japanese Patent Laid-Open No. 2005-23972 As described in the official gazette and the like, the contact fitting is axially spaced from the second attachment member, and the second attachment member and the contact fitting are connected by the main rubber elastic body. The first mounting member may be separated from the main rubber elastic body in the rebound direction by bringing the first mounting member into contact with the contact metal fitting.

  Furthermore, in the above-described embodiments, specific examples of the present invention applied to an automobile engine mount have been described. However, the present invention is not limited to an automobile body mount, a differential mount, or the like, and other vibration isolating mounts for various vibrators other than an automobile. However, it goes without saying that both are applicable.

The longitudinal section explanatory view of the engine mount as one embodiment of the present invention. The longitudinal cross-sectional explanatory drawing for demonstrating the one way valve provided in the engine mount. The graph which shows the damping characteristic of the fluid enclosure type vibration isolator made into the structure according to this invention, and the fluid enclosure type vibration isolator according to the conventional structure. The graph which shows the dynamic spring characteristic of the fluid enclosure type vibration isolator made into the structure according to this invention, and the fluid enclosure type vibration isolator according to the conventional structure. The longitudinal cross-sectional explanatory drawing for demonstrating the different aspect of a one-way valve. The longitudinal cross-sectional explanatory drawing for demonstrating the further different aspect of a one-way valve.

Explanation of symbols

10: engine mount, 12: first mounting bracket, 14: second mounting bracket, 16: rubber elastic body, 34: partition member, 44: first series passage, 46: second communication passage, 68: movable Rubber membrane, 76: working air chamber, 82: one-way valve, 98: minute intake hole, 100: diaphragm, 106: fluid chamber, 108: pressure receiving chamber, 110: equilibrium chamber, 112: intermediate chamber, 114: first Orifice passage, 116: second orifice passage

Claims (6)

A first attachment member attached to one member to be vibration-proof connected;
A second attachment member attached to the other member to be vibration-proof connected;
A main rubber elastic body for elastically connecting the first mounting member and the second mounting member;
A pressure receiving chamber filled with an incompressible fluid in which a part of the wall portion is constituted by the main rubber elastic body so that a pressure fluctuation is caused at the time of vibration input; and
An equilibrium chamber in which a part of the wall portion is made of a flexible film and has a variable volume, and an incompressible fluid is enclosed,
An intermediate chamber in which a part of the wall portion is composed of an elastic partition wall and in which an incompressible fluid is enclosed;
A first fluid flow path communicating the pressure receiving chamber and the intermediate chamber;
A second fluid flow path communicating between the equilibrium chamber and the intermediate chamber;
A working air chamber formed on the opposite side of the intermediate chamber across the elastic partition;
A one-way valve that allows air to be discharged from the working air chamber to the outer space but prevents air from flowing from the outer space to the working air chamber;
The working air chamber communicates with the external space, and in the input state of the vibration in the tuning frequency range in which the vibration isolating effect due to the fluid action of the fluid flowing through the second fluid channel is exerted, the working air chamber Inadequate air inflow is allowed to recover the amount of air discharged through the one-way valve, and in the non-input state of the vibration in the tuning frequency range, the initial stage of the working air chamber is based on the elasticity of the elastic partition wall. A fluid-filled vibration isolator including a fine air intake hole that allows air inflow sufficient to restore the volume.   In the working air chamber, an inner surface facing the elastic partition wall is a vibration input in a tuning frequency range in which a vibration isolating effect due to a fluid action of fluid fluidized through the second fluid flow path is exerted, and the one-way valve The fluid sealing according to claim 1, wherein at least a part of the elastic partition wall is brought into contact with a decrease in volume of the working air chamber due to air being discharged through the working air chamber. Type vibration isolator.   The elastic partition that defines the working air chamber has a curved convex shape that swells in a substantially dome shape toward the intermediate chamber, and an opposing inner surface of the working air chamber that faces the elastic partition has the elasticity The fluid-filled vibration damping device according to claim 1 or 2, wherein the vibration-filled vibration damping device has a curved concave shape that is recessed toward the opposite side of the partition wall.   The minute air intake hole is discharged from the working air chamber through the one-way valve in an input state of vibration in a tuning frequency range in which a vibration isolation effect due to a fluid action of the fluid that is caused to flow through the first fluid flow path is exhibited. The fluid-filled vibration isolator according to any one of claims 1 to 3, wherein air inflow sufficient to recover the amount of air to be recovered is allowed.   The fluid-filled vibration isolator according to any one of claims 1 to 4, wherein a preload is set in the one-way valve to maintain a closed state until a positive pressure from the working air chamber reaches a predetermined value. .   The second mounting member includes a cylindrical portion, the first mounting member is disposed on one opening side of the cylindrical portion, and the first mounting member and the second mounting member are arranged. One side of the cylindrical portion is closed by the main rubber elastic body to be connected, while the other opening of the cylindrical portion is closed by the flexible film. An incompressible fluid sealing region is formed between the opposing surfaces of the flexible film and the flexible membrane, and a partition member is disposed between the opposing surfaces of the main rubber elastic body and the flexible membrane. The pressure receiving chamber is formed between the partition member and the main rubber elastic body, and the equilibrium chamber is formed between the partition member and the flexible membrane. Further, the intermediate chamber and the air chamber are formed inside the partition member. Fluid filled type vibration damping device.

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