JP2009079678A - Anti-vibration device, and manufacturing method of anti-vibration device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an anti-vibration device of a novel structure capable of securing a larger degree of tuning freedom of anti-vibration characteristics. <P>SOLUTION: In the anti-vibration device, a rubber elastic body 16 of the main body connecting a first attachment member 12 attached to one member composing a vibration transmitting system and a second attachment member 14 attached to another member composing the vibration transmitting system, and an elastic rubber wall 52 of a liquid seal unit 42 formed separately from the rubber elastic body 16 abut on each other in a vibration input direction in an abutting protruding part 36 provided on at least one of the rubber elastic body 16 and the elastic rubber wall 52. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a vibration isolator that can be suitably employed as, for example, an engine mount of an automobile, and more particularly to a fluid-filled vibration isolator using a vibration isolating effect based on a fluid action of a fluid sealed inside. It is.

  Conventionally, the first attachment member attached to one member constituting the vibration transmission system is located on one opening side of the cylindrical portion of the second attachment member attached to the other member constituting the vibration transmission system. A vibration isolator having a structure in which the first mounting member and the second mounting member are connected to each other by a main rubber elastic body is known.

  In addition, for the purpose of further improving the vibration isolation performance, there is also a fluid filled type vibration isolation device in which an incompressible fluid is enclosed inside the vibration isolation device so as to obtain a vibration isolation effect based on the fluid action of the sealed fluid. Proposed. As such a fluid-filled vibration isolator, for example, as shown in Patent Document 1 (Japanese Patent Laid-Open No. 7-71506) and the like, a fluid chamber formed in the cylindrical portion of the second mounting member The partition member that bisects the volume is supported by the second mounting member, and a main liquid chamber is formed on one side across which the partition member is sandwiched to generate pressure fluctuations upon vibration input. There is generally known a structure in which a secondary liquid chamber in which a volume change is allowed is formed on the other side, and an orifice passage is formed in which the main liquid chamber and the secondary liquid chamber communicate with each other. .

  By the way, it is desirable that the anti-vibration characteristics of the anti-vibration device can be changed as needed. However, the anti-vibration characteristics of the anti-vibration device are determined by the shape of the main rubber elastic body, the rubber volume, the passage length of the orifice passage, the passage cross-sectional area, and the like. Therefore, the anti-vibration characteristics of the vibration isolator are determined at the time of manufacturing the vibration isolator, and it is difficult to change after the manufacture.

  Therefore, the applicant of the present invention previously described in Japanese Patent Application No. 2007-73909, the partition member that bisects the fluid chamber formed in the cylindrical housing is supported by the cylindrical housing, and one side sandwiching the partition member A main liquid chamber in which a part of the wall part is formed of an elastic rubber wall is formed, and a part of the wall part is formed of a flexible film on the other side across the partition member. Furthermore, a liquid seal unit having a structure in which the main liquid chamber and the sub liquid chamber are communicated with each other through an orifice passage, and an elastic rubber wall overlaps the main rubber elastic body in the main vibration input direction. The vibration isolator of the structure fixed to the 2nd attachment member so that it could match was proposed.

  In such a vibration isolator, since the liquid seal unit provided with the orifice passage is formed separately from the main rubber elastic body, a plurality of types of liquid seal units having different vibration isolation characteristics are prepared. By using an appropriate liquid sealing unit from among the liquid sealing units, it is possible to meet the required anti-vibration characteristics.

  However, as a result of further examination by the inventor of the vibration isolator according to the prior application, simply allowing the liquid seal unit to be replaced provides a degree of freedom in tuning the vibration isolation characteristics with respect to the required characteristics. It turns out that it may still be difficult to make it large enough.

Japanese Patent Laid-Open No. 7-71506

  Here, the present invention has been made in the background as described above, and the problem to be solved is that it has a novel structure that can ensure a greater degree of freedom in tuning the vibration isolation characteristics. The object is to provide a vibration isolator.

  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.

  The present invention is an anti-vibration device mounted between members constituting a vibration transmission system, wherein one opening of a cylindrical housing is closed with an elastic rubber wall, and the other opening of the cylindrical housing is A fluid chamber is formed which is closed by a flexible membrane and in which an incompressible fluid is sealed between the opposing surfaces of the elastic rubber wall and the flexible membrane. A partition member is supported by the cylindrical housing, and a main liquid chamber in which a part of the wall portion is formed of an elastic rubber wall is formed on one side of the partition member, and the other of the partition member is sandwiched A liquid seal unit having a structure in which a secondary liquid chamber, part of which is made of a flexible film, is formed on the side of the wall and the main liquid chamber and the secondary liquid chamber are communicated with each other through an orifice passage. In the main rubber elastic body formed separately from the liquid sealing unit, the main A first attachment member attached to one member constituting the vibration transmission system is fixed to a central portion of one end portion in the dynamic input direction, while the other end in the main vibration input direction in the main rubber elastic body The liquid sealing unit is disposed on the side of the main body, and the elastic rubber wall of the liquid sealing unit is positioned opposite to the other end surface of the main rubber elastic body in the main vibration input direction, so that the elastic rubber wall and the main rubber elastic body are The cylindrical housing of the liquid seal unit is brought into contact with the outer peripheral surface of the main rubber elastic body, and is brought into contact with the elastic rubber wall and the main rubber elastic body so as to protrude from at least one side of the main rubber elastic body. A second attachment member attached to the other member constituting the vibration transmission system by being fixedly attached to the structure includes a cylindrical housing.

  In the vibration isolator having the structure according to the present invention, the main rubber elastic body and the elastic rubber wall that are opposed to each other in the vibration input direction are provided on at least one of the main rubber elastic body and the elastic rubber wall. The contact area between the main rubber elastic body and the elastic rubber wall can be changed by changing the shape, size, formation position, etc. of the contact protrusion. It is possible to change the change characteristic of the contact state when the load is input. Thereby, the magnitude of the pressing force exerted on the elastic rubber wall from the main rubber elastic body when vibration is input is changed to adjust the mode of elastic deformation of the elastic rubber wall when vibration is input. Is possible. As a result, it is possible to tune the anti-vibration characteristics exhibited based on the fluid flow action of the fluid flowing through the orifice passage by adjusting the magnitude of the pressure fluctuation exerted on the main liquid chamber.

  Therefore, in the vibration isolator of the present invention, not only the design of the liquid sealing unit is changed, but also the shape, size, formation position, etc. of the contact protrusion is changed, so that the fluid that can flow through the orifice passage is changed. It is possible to change the anti-vibration characteristics based on the fluid action or the like. As a result, it is possible to increase the degree of freedom in tuning the vibration isolation characteristics.

  Moreover, in this invention, it is desirable that the contact protrusion is formed over the entire circumference in the circumferential direction around the elastic central axis of the main rubber elastic body. This makes it possible to exert a stable pressing force on the elastic rubber wall.

  Further, in the present invention, it is desirable that the contact protrusion is a rubber protrusion integrally formed with the elastic rubber wall or the main rubber elastic body. Thereby, manufacture of a vibration isolator becomes easy.

  Furthermore, in the present invention, the main rubber elastic body has a truncated cone shape, and the first mounting member is fixed to the end surface on the small diameter side of the main rubber elastic body, while the main rubber elastic body is large. The inner peripheral surface of the cylindrical portion of the second mounting bracket is fixed to the outer peripheral surface of the radial side end, and the cylindrical housing of the liquid seal unit is attached to the cylindrical portion of the second mounting bracket. While being fitted and fixed, the large-diameter side end surface of the main rubber elastic body may be overlaid on the elastic rubber wall of the liquid seal unit.

  In the present invention, a plurality of main rubber elastic bodies are prepared, and a vibration isolator is manufactured by combining a main rubber elastic body selected from the plurality of main rubber elastic bodies and a liquid seal unit. Alternatively, a plurality of types of liquid sealing units may be prepared, and a vibration isolator may be manufactured by combining a liquid sealing unit selected from the plurality of types of liquid sealing units and a main rubber elastic body. As a result, it is possible to secure a greater degree of tuning freedom.

  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 vibration isolator according to the present invention. The engine mount 10 includes a first mounting member 12 as a first mounting member attached to one member constituting the vibration transmission system, and a second attachment member attached to the other member constituting the vibration transmission system. The second mounting bracket 14 has a structure in which the main rubber elastic bodies 16 are connected to each other. In the following description, the vertical direction is basically the vertical direction in FIG. 1 which is the main vibration input direction in the present embodiment. FIG. 1 shows a state where the engine mount 10 according to the present embodiment is not attached to the vehicle.

  More specifically, the first mounting bracket 12 is made of a rigid material such as iron or aluminum alloy, and has a substantially cylindrical shape with a small diameter as a whole as shown in FIG. . Further, a flange portion 18 that extends to the outer peripheral side is integrally formed at the upper end edge of the first mounting member 12. Further, a bolt hole 20 extending in a predetermined length in the axial direction is formed in the central portion in the radial direction of the first mounting bracket 12, and a female screw is engraved on the inner peripheral surface of the bolt hole 20.

  On the other hand, the second mounting bracket 14 is configured to include an outer cylindrical bracket 22 as a cylindrical portion. The outer cylinder fitting 22 is formed of the same highly rigid material as the first attachment fitting 12, and has a large-diameter, generally cylindrical shape extending in the axial direction. Further, in the present embodiment, a stepped portion 24 is formed at substantially the center in the axial direction of the outer cylindrical metal member 22, the small axial portion 26 is formed on the upper side in the axial direction across the stepped portion 24, and the lower side in the axial direction is The large diameter cylindrical portion 28 is larger than the small diameter cylindrical portion 26.

  The first mounting bracket 12 and the outer cylindrical bracket 22 are disposed on substantially the same central axis, and the first mounting bracket 12 is spaced apart from the opening portion on the upper side in the axial direction of the outer cylindrical bracket 22. The first mounting member 12 and the outer tube member 22 are connected to each other by the main rubber elastic body 16.

  As shown in FIG. 2, the main rubber elastic body 16 is a rubber elastic body having a substantially frustoconical shape, and has a large-diameter central recess that opens downward in the radial central portion. 30 is formed. In particular, the central recess 30 of the present embodiment includes a tapered surface 32 that gradually increases in diameter from the upper side in the axial direction to the lower side. An annular step surface 34 that extends in the direction perpendicular to the axis is formed on the outer peripheral side of the central recess 30.

  Furthermore, in this embodiment, a rubber protrusion 36 as a contact protrusion is provided on the tapered surface 32 of the central recess 30. The rubber protrusion 36 is formed of a conventionally known rubber material, and is integrally formed with the main rubber elastic body 16 in this embodiment.

  In the present embodiment, the rubber protrusion 36 has a substantially constant cross-sectional shape and is formed over the entire circumference of the central recess 30 around the elastic central axis 38 of the main rubber elastic body 16. It has a ring shape. That is, the rubber protrusion 36 according to the present embodiment is formed in the direction perpendicular to the axis of the main rubber elastic body 16 and the central recess 30 (diameter in the projection in the direction in which the elastic central axis 38 of the main rubber elastic body 16 extends. It is formed in an annular shape in the middle part of the direction. In particular, in the present embodiment, the inner peripheral edge of the rubber protrusion 36 is positioned on the outer peripheral side with respect to the center position (half the radius) of the main rubber elastic body 16 and the central recess 30.

  Further, in the present embodiment, the protruding height of the rubber protrusion 36 is substantially constant over the entire circumference. In particular, in the present embodiment, the protruding tip surface of the rubber protrusion 36 is more than the step surface 34. It is positioned axially upward. In other words, the protruding front end surface of the rubber protrusion 36 is positioned in the central recess 30 and does not protrude outside the central recess 30.

  Furthermore, in this embodiment, the protruding end surface of the rubber protrusion 36 is an annular flat surface that extends in a direction orthogonal to the elastic central axis 38 of the main rubber elastic body 16, and is parallel to the step surface 34. Has been. The protruding end surface of the rubber protrusion 36 does not need to be a flat surface, and may have a shape corresponding to the surface of a tapered portion 58 in the elastic rubber wall 52 described later, with which the rubber protrusion 36 abuts. It may be a curved surface shape with an appropriate curvature.

  In the present embodiment, the base end side of the rubber protrusion 36 is thicker than the protruding end side. Thereby, the durability of the rubber protrusion 36 is ensured.

  In the central portion of the upper end portion, which is the end portion on the small diameter side of the main rubber elastic body 16 as described above, the first mounting bracket 12 is embedded and vulcanized and bonded over substantially the entire portion excluding the flange portion 18. Further, the inner peripheral surface of the small diameter cylindrical portion 26 of the outer cylinder fitting 22 is overlapped and vulcanized and bonded to the outer peripheral surface of the lower end portion which is the large diameter side end portion of the main rubber elastic body 16. Thus, the first mounting member 12 and the outer tube member 22 are connected to each other by the main rubber elastic body 16. As is clear from the above description, in the present embodiment, the main rubber elastic body 16 is formed as an integrally vulcanized molded product 40 including the first mounting member 12 and the outer tube member 22.

  Further, a liquid seal cassette 42 as a liquid seal unit formed separately from the integral vulcanization molded product 40 is assembled to the integral vulcanization molded product 40 of the main rubber elastic body 16.

  More specifically, the liquid seal cassette 42 includes a housing fitting 44 as a cylindrical housing as shown in FIG. The housing bracket 44 has a thin large-diameter cylindrical shape as a whole, and the upper side in the axial direction is a large-diameter portion 48 across the stepped portion 46 formed in the axially intermediate portion, while the lower side in the axial direction is The small diameter portion 50 is used.

  An elastic rubber wall 52 is disposed at the upper end portion of the housing fitting 44. The elastic rubber wall 52 includes an upper bottom wall 54 and a cylindrical wall 56, and has an inverted cup shape as a whole. Therefore, the upper bottom wall 54 of the present embodiment is formed with a tapered portion 58 that gradually decreases in diameter as it goes upward in the axial direction. As a result, the upper bottom wall 54 is convex upward. In particular, in the present embodiment, the upper surface of the upper bottom wall 54 of the elastic rubber wall 52 has a shape corresponding to the lower end surface (large-diameter side end surface) in the axial direction of the main rubber elastic body 16 excluding the rubber protrusion 36. .

  Such an elastic rubber wall 52 is formed by vulcanizing and bonding the outer peripheral surface of the cylindrical wall 56 to the inner peripheral surface of the large-diameter portion 48 of the housing metal fitting 44, so ). Thus, the opening on the upper side in the axial direction of the housing fitting 44 is covered with the elastic rubber wall 52 in a fluid-tight manner. As is clear from this, in the present embodiment, the elastic rubber wall 52 is formed as an integrally vulcanized molded product provided with the housing fitting 44.

  Therefore, in this embodiment, a portion of the cylindrical wall 56 of the elastic rubber wall 52 that is positioned above the opening end surface on the upper side in the axial direction of the housing fitting 44, in other words, the housing of the cylindrical wall 56 of the elastic rubber wall 52. In a portion not vulcanized and bonded to the metal fitting 44, a notch groove 59 is formed over the entire circumference at the outer peripheral edge at the upper end in the axial direction. Thus, the outer peripheral surface of the portion of the cylindrical wall 56 of the elastic rubber wall 52 that is not vulcanized and bonded to the housing fitting 44 is the outer periphery of the portion of the cylindrical wall 56 of the elastic rubber wall 52 that is vulcanized and bonded to the housing fitting 44. It is positioned radially inward (inner axis perpendicular direction) from the surface.

  In the present embodiment, the cylindrical wall 56 of the elastic rubber wall 52 extends to the inner peripheral surface of the large-diameter portion 48 of the housing fitting 44. Thereby, the seal rubber 60 integrally formed with the cylindrical wall 56 of the elastic rubber wall 52 is attached to the inner peripheral surface of the large diameter portion 48 of the housing metal fitting 44 over the entire circumference.

  The elastic rubber wall 52 is separate from the main rubber elastic body 16, and in this embodiment, performance required for the main rubber elastic body 16 and the elastic rubber wall 52 (for example, durability performance or encapsulation) The composition of the rubber material of the main rubber elastic body 16 and the elastic rubber wall 52 is made different according to the resistance to erosion by the fluid.

  In addition, a diaphragm 62 as a flexible film is assembled to the lower end portion of the housing fitting 44. The diaphragm 62 is formed of a thin, substantially disk-shaped rubber film having sufficient slack, the central portion is substantially domed, and the outer peripheral portion has rippled slack. . A fixing metal fitting 64 is fixed to the outer peripheral edge of the diaphragm 62. The fixture 64 is a highly rigid member and has a large-diameter, generally annular shape. In this embodiment, the outer peripheral surface of the diaphragm 62 is vulcanized and bonded to the inner peripheral surface of the fixing metal 64, so that the diaphragm 62 is formed as an integrally vulcanized molded product including the fixing metal 64.

  Such a diaphragm 62 is interpolated at the lower end portion of the housing fitting 44. The housing fitting 44 is subjected to diameter reduction processing such as eight-way drawing, so that the fixing fitting 64 vulcanized and bonded to the diaphragm 62 is fitted and fixed to the housing fitting 44. .

  In addition, the fixing fitting 64 of the diaphragm 62 is fluid-tightly overlapped with the housing fitting 44 via the seal rubber layer 60, so that the upper opening is fluid-tightly closed by the elastic rubber wall 52. The lower opening is closed fluid-tight with the diaphragm 62. Accordingly, a fluid sealing region 66 as a fluid chamber sealed from the outside is formed between the elastic rubber wall 52 and the diaphragm 62 on the inner peripheral side of the housing fitting 44. Further, in the fluid sealing region 66, incompressible fluid such as water, alkylene glycol, polyalkylene glycol, silicone oil, or a mixture thereof is sealed as a sealing fluid. The sealed fluid is not particularly limited, but the viscosity is 0.1 Pa · s or less in order to advantageously obtain a vibration isolating effect based on the resonance action of the fluid flowing through the orifice passage 90 described later. It is desirable to employ a low viscosity fluid. In addition, such a fluid sealing can be advantageously realized by assembling the diaphragm 62 and the partition member 68 described later to the housing fitting 44 in an incompressible fluid.

  A partition member 68 is accommodated in the fluid sealing region 66 and supported by the housing fitting 44. The partition member 68 as a whole has a thick and substantially disk shape. In this embodiment, the partition member 68 has a structure in which a holding fitting 72 and a movable rubber film 74 are assembled to the partition member main body 70.

  The partition member main body 70 is a member having a thick, substantially disk shape, and is formed of, for example, a hard synthetic resin material reinforced with fiber in the present embodiment. A large-diameter recess 76 is formed in the central portion of the partition member main body 70 in the radial direction. The large-diameter recess 76 is a shallow circular recess and is opened downward. Further, a through hole 78 is formed at the center of the bottom wall of the large diameter recess 76. The through-hole 78 is a circular hole having a smaller diameter than the large-diameter recess 76 and is formed so as to penetrate the partition member main body 70 in the axial direction. A circumferential groove 80 is formed on the outer peripheral edge of the partition member main body 70. The circumferential groove 80 is a concave groove extending in the circumferential direction with a predetermined length, and is formed so as to open on the outer circumferential surface of the partition member main body 70.

  A holding metal fitting 72 is assembled to the partition member main body 70. The holding metal fitting 72 has a thin, substantially annular plate shape, and has a stepped shape in which the central portion is positioned above the outer peripheral portion. The holding metal 72 is overlapped with the lower end surface of the partition member main body 70, and a plurality of engaging claws 82 protruding from the lower end surface of the partition member main body 70 are formed through the holding metal 72 and are not shown. It is fixed with respect to the partition member main body 70 by being inserted into the stop hole and locked.

  A movable rubber film 74 is disposed between the opposing surfaces of the partition member main body 70 and the holding fitting 72. The movable rubber film 74 is formed of a rubber elastic body having a substantially disk shape having a larger diameter than the through-hole 78 formed in the partition member main body 70. Further, a support portion is integrally formed on the outer peripheral edge portion of the movable rubber film 74, and extends around the entire circumference with a substantially constant circular cross section so as to be thicker than the central portion. Such a movable rubber film 74 is supported by sandwiching the outer peripheral edge portion between the bottom wall portion of the large-diameter recess 76 of the partition member main body 70 and the axially opposed surface of the central portion of the holding metal fitting 72. Accordingly, the partition member main body 70 and the holding metal fitting 72 are fixedly assembled. Further, the central portion of the movable rubber film 74 is disposed so as to close the through hole 78 of the partition member main body 70 and the central hole of the holding fitting 72 under the assembled state. It is assembled in a state where displacement in the axial direction due to elastic deformation is allowed.

  The partition member 68 having the above-described structure is assembled to the housing fitting 44. That is, the partition member 68 is accommodated in a fluid sealing region 66 formed between the elastic rubber wall 52 and the diaphragm 62 in the axial direction on the inner peripheral side of the housing fitting 44. Further, the upper end surface of the partition member 68 is overlapped with the inner peripheral edge of the lower end of the cylindrical wall 56 of the elastic rubber wall 52, and the lower end surface is overlapped with the upper end surface of the fixing metal fitting 64 that is vulcanized and bonded to the diaphragm 62. Positioned in the vertical direction. Then, by subjecting the housing fitting 44 to diameter reduction processing such as an eight-way drawing, the outer peripheral surface of the partition member 68 is pressed against the inner peripheral surface of the housing fitting 44 via the seal rubber layer 60, and the partition member 68. Is internally fitted and fixed to the housing fitting 44.

  In the present embodiment, the partition member 68 and the fixing bracket 64 are assembled to the housing bracket 44 at the same time. Further, the lower end edge portion of the fixing bracket 64 is overlapped in the axial direction with the caulking portion 84 formed at the lower end (small diameter end) in the axial direction of the housing bracket 44, and the partition member 68 and the fixing bracket 64 are elastic. The cylindrical wall 56 of the rubber wall 52 and the caulking portion 84 are positioned in the axial direction (vertical direction).

  Under such an assembly state of the partition member 68 to the housing metal fitting 44, the outer peripheral surface of the partition member 68 is brought into close contact with the inner peripheral surface of the housing metal fitting 44 through the seal rubber layer 60, whereby the fluid sealing region 66 is formed. The partition member 68 is divided into two parts in the vertical direction. As a result, on one side (upper side in FIG. 1) sandwiching the partition member 68, a part of the wall portion is constituted by the elastic rubber wall 52, and serves as a main liquid chamber to which internal pressure fluctuations are exerted when vibration is input. A pressure receiving chamber 86 is formed, and on the other side (lower side in FIG. 1) across the partition member 68, a part of the wall portion is configured by the diaphragm 62, so that the volume change is easily allowed. An equilibrium chamber 88 is formed as a secondary liquid chamber.

  Further, the outer peripheral surface of the partition member 68 is brought into close contact with the inner peripheral surface of the housing metal member 44 via the seal rubber layer 60, so that the opening portion of the circumferential groove 80 opened to the outer peripheral surface of the partition member 68 becomes the housing metal member 44. Is covered fluidly. As a result, a tunnel-like flow path extending in the circumferential direction with a predetermined length is formed. Further, the tunnel-shaped flow path has one end in the circumferential direction communicating with the pressure receiving chamber 86 through a communication hole 85 formed in the partition member main body 70, and the other end in the circumferential direction is connected to the partition member main body. 70 and the holding fitting 72 are connected to the equilibrium chamber 88 through a communication hole (not shown). Thus, an orifice passage 90 that communicates the pressure receiving chamber 86 and the equilibrium chamber 88 with each other is formed using the circumferential groove 80. In the present embodiment, the opening (communication hole 85) of the orifice passage 90 on the pressure receiving chamber 86 side is provided so as to open to a communication protrusion 92 that protrudes upward from the partition member main body 70. In addition, an opening (communication hole 85) on the pressure receiving chamber 86 side of the orifice passage 90 is opened toward the inner peripheral side.

  In addition, the orifice passage 90 in the present embodiment is tuned so that the resonance frequency of the fluid that flows inside is in a low frequency range of about 10 Hz, and with respect to low frequency vibration corresponding to an engine shake of an automobile or the like. The vibration isolation effect based on the flow action such as the resonance action of the fluid flowing through the orifice passage 90 is effectively exhibited. Such tuning of the orifice passage 90 can be set by appropriately adjusting the ratio of the passage length and the passage sectional area of the orifice passage 90.

  As shown in FIG. 1, the liquid seal cassette 42 having the structure as described above is formed into an integral vulcanization molded product 40 of the main rubber elastic body 16 provided with the first mounting bracket 12 and the outer cylindrical bracket 22. It is assembled against. That is, the housing metal fitting 44 is fixed to the outer cylinder fitting 22 by press-fitting the large diameter portion 48 of the housing fitting 44 constituting the liquid seal cassette 42 into the large diameter cylinder portion 28 of the outer cylinder fitting 22. The liquid seal cassette 42 is assembled to the integrally vulcanized molded product 40 in a state where it is disposed below the main rubber elastic body 16. In the present embodiment, the outer cylinder fitting 22 and the housing fitting 44 are connected and fixed to each other, whereby the second fitting 14 is constituted by the outer cylinder fitting 22 and the housing fitting 44.

  Further, in a stationary state in which the liquid seal cassette 42 is assembled to the integrally vulcanized molded product 40 of the main rubber elastic body 16, the central portion of the upper bottom wall 54 of the elastic rubber wall 52 (a direction perpendicular to the axis from the taper portion 58). The disc-shaped portion positioned inward) is entirely with respect to the center of the upper bottom surface of the central recess 30 formed in the main rubber elastic body 16 (a circular surface positioned inwardly in the direction perpendicular to the taper surface 32). In addition, the upper end surface of the cylindrical wall 56 of the elastic rubber wall 52 is overlapped over the entire stepped surface 34 of the main rubber elastic body 16.

  Further, in a stationary state in which the liquid seal cassette 42 is assembled to the integrally vulcanized molded product 40 of the main rubber elastic body 16, a notch groove formed in the outer peripheral edge in the axial direction of the cylindrical wall 56 of the elastic rubber wall 52. A gap 94 is formed between 59 and the outer tube fitting 22 over the entire circumference.

  Furthermore, in a stationary state where the liquid seal cassette 42 is assembled to the integrally vulcanized molded product 40 of the main rubber elastic body 16, the rubber protrusion 36 provided on the main rubber elastic body 16 is formed on the elastic rubber wall 52. It is pressed against the tapered portion 58 of the upper base 54 and is brought into contact with the tapered portion 58 over the entire circumference. That is, the rubber protrusion 36 provided on the main rubber elastic body 16 has an entire circumference with respect to the intermediate portion in the radial direction (intermediate portion perpendicular to the axis) of the free length portion of the elastic rubber wall 52 shown in FIG. It is made to contact | abut over. In particular, in this embodiment, the rubber protrusion 36 provided on the main rubber elastic body 16 extends over the entire circumference with respect to a position that is outward from the radial center position of the free length portion of the elastic rubber wall 52. It can come into contact. The free length portion of the elastic rubber wall 52 refers to a portion where elastic deformation is allowed when an external pressing force is applied. In particular, in this embodiment, the cylindrical wall 56 of the elastic rubber wall 52 has an outer peripheral surface and a lower end portion restrained or supported by the large-diameter portion 48 of the housing fitting 44 and the partition member main body 70. A bridging portion of the inner peripheral surface of the cylindrical wall 56 becomes a free length portion of the elastic rubber wall 52.

  Further, as described above, the rubber protrusion 36 is brought into contact with the taper portion 58 over the entire circumference, so that the intermediate portion in the radial direction (perpendicular to the axis) of the taper portion 58 is convex downward in the axial direction. It is elastically deformed so that As a result, the tapered portion 58 of the elastic rubber wall 52 is brought into contact with the main rubber elastic body 16 only at the rubber protrusion 36. In other words, between the upper surface of the taper portion 58 of the elastic rubber wall 52 and the taper surface 32 of the central recess 30, the rubber protrusion 36 is sandwiched in the radial direction (axially perpendicular direction) inward and outward, respectively. Gaps 96 and 98 are formed. The gaps 96 and 98 can be eliminated by appropriately adjusting the shapes of the rubber protrusion 36 and the taper portion 58.

  Further, as described above, the liquid seal cassette 42 is integrally vulcanized and molded with the main rubber elastic body 16 by elastically deforming the radially intermediate portion of the tapered portion 58 so as to protrude downward in the axial direction. The elastic rubber wall 52 is restored to its original shape by the restoring force of the elastic rubber wall 52 itself in a stationary state assembled to the product 40, and as a result, the rubber protrusion 36 contacts the tapered portion 58. The state in which the main rubber elastic body 16 is in contact with the elastic rubber wall 52 is maintained.

  Here, an air communication hole 100 is formed in the stepped portion 24 of the outer cylinder fitting 22. The air communication holes 100 are provided at a plurality of locations on the circumference of the outer cylinder fitting 22 and are formed so as to penetrate the stepped portion 24 of the outer cylinder fitting 22 in the thickness direction. Further, in the present embodiment, under the assembled state of the outer cylinder fitting 22 and the housing fitting 44, the atmosphere communication hole 100 is connected to the notch groove 59 formed in the outer peripheral edge of the upper end of the cylinder wall 56 of the elastic rubber wall 52. It communicates with a gap 94 formed between the tube fittings 22.

  The automobile engine mount 10 having such a structure is attached to a power unit (not shown) as one member constituting a vibration transmission system by a fixing bolt (not shown) in which the first mounting bracket 12 is screwed into the bolt hole 20. At the same time, the second mounting bracket 14 is attached to a vehicle body (not shown) via a bracket (not shown) as the other member constituting the vibration transmission system, so that it is interposed between the power unit and the vehicle body, The power unit is supported in a vibration-proof manner with respect to the vehicle body. Although not shown, the rubber protrusion 36 of the main rubber elastic body 16 is pressed against the tapered portion 58 of the elastic rubber wall 52 in a state where the engine mount 10 is mounted between the power unit and the vehicle body. .

  When vibration is input in the vertical direction, which is the main vibration input direction, between the first mounting bracket 12 and the second mounting bracket 14 in the mounted state of the engine mount 10, based on the fluid flow action and the like. The intended anti-vibration effect is exhibited.

  That is, when a low-frequency large-amplitude vibration such as an engine shake is input between the first mounting bracket 12 and the second mounting bracket 14 during driving of the automobile, etc., the elastic body 16 is elastically deformed. Thus, the elastic rubber wall 52 superimposed on the main rubber elastic body 16 is elastically deformed. Due to the elastic deformation of the elastic rubber wall 52, pressure fluctuation is exerted in the pressure receiving chamber 86. As a result, a fluid flow is generated between the pressure receiving chamber 86 and the equilibrium chamber 88 through the orifice passage 90 tuned to a low frequency range corresponding to an engine shake or the like, and based on a fluid action such as a resonance action of the fluid. Anti-vibration effects such as a high damping effect are effectively exhibited. In addition, when the vibration is input in the low frequency range, the amplitude of the input vibration is large, so that the hydraulic pressure absorption effect due to the minute elastic deformation of the movable rubber film 74 is not effectively exhibited. Therefore, a sufficient internal pressure fluctuation is exerted on the pressure receiving chamber 86, and fluid flow through the orifice passage 90 can be advantageously generated.

  Particularly in the present embodiment, the upper end surface of the cylindrical wall 56 of the elastic rubber wall 52 is pressed against the step surface 34 formed on the outer peripheral edge of the lower end surface of the main rubber elastic body 16 in the axial direction. The central portion of the upper bottom wall 54 of the elastic rubber wall 52 is pressed against the center of the upper bottom surface of the central recess 30 formed in the main rubber elastic body 16 in the axial direction. Thus, during normal vibration input to be damped, the central portion of the elastic rubber wall 52 (the central portion of the upper bottom wall 54) and the outer peripheral portion (the cylindrical wall 56) are brought into contact with the main rubber elastic body 16. The gaps 96 and 98 formed between the main rubber elastic body 16 and the elastic rubber wall 52 are sealed from the outside (in the atmosphere). As a result, the displacement due to the elastic deformation of the main rubber elastic body 16 is effectively transmitted to the elastic rubber wall 52, and the pressure fluctuation is exerted in the pressure receiving chamber 86. The main rubber elastic body 16 and the elastic rubber wall 52 are overlapped when the main rubber elastic body 16 is displaced in a direction away from the elastic rubber wall 52 (in this embodiment, upward in FIG. 1). The pressure in the gaps 96 and 98 formed between the surfaces decreases, and the elastic rubber wall 52 is sucked toward the main rubber elastic body 16, whereby the main rubber elastic body 16 and the elastic rubber wall 52 are elastically integrated. This is because it can be deformed. Therefore, at the time of inputting vibration isolation target vibration, the vibration isolation effect based on the fluid action of the fluid flowing through the orifice passage 90, the fluid pressure absorption action by the movable rubber film 74, and the like can be effectively exhibited.

  In the engine mount 10 having the above-described structure, the rubber protrusion 36 is pressed against the tapered portion 58 of the upper bottom wall 54 of the elastic rubber wall 52, so A large pressing force is partially applied to the tapered portion 58 of the bottom wall 54 so that the tapered portion 58 of the upper bottom wall 54 of the elastic rubber wall 52 is elastically deformed in advance so as to protrude downward in the axial direction. It has been. In this state, since vibration is input, it is possible to easily cause elastic deformation of the upper bottom wall 54 of the elastic rubber wall 52. As a result, it is possible to increase the area where the elastic deformation occurs in the upper base 54 of the elastic rubber wall 52 when vibration is input, and it is possible to increase the pressure fluctuation generated in the pressure receiving chamber 86. As a result, it is possible to secure a large amount of fluid that can flow through the orifice passage 90, and to further improve the vibration isolation effect based on the fluid action of the fluid that can flow through the orifice passage 90. Become.

  Therefore, in the engine mount 10 according to the present embodiment, by changing the formation position, size, shape, and the like of the rubber protrusion 36, a region that is elastically deformed in the upper bottom wall 54 of the elastic rubber wall 52 when vibration is input is provided. It is possible to change the flow amount of the fluid that is caused to flow through the orifice passage 90 by changing the magnitude of the pressure fluctuation generated in the pressure receiving chamber 86. As a result, it is possible to change the anti-vibration characteristics that are exhibited based on the flow action of the fluid that flows through the orifice passage 90.

  In particular, in the present embodiment, since the liquid seal cassette 42 is separated from the integrally vulcanized molded product 40 of the main rubber elastic body 16, a plurality of types of liquid seal cassettes 42 having different anti-vibration characteristics are prepared. From among the plurality of types of liquid seal cassettes 42, a liquid seal cassette 42 required for the required vibration isolation characteristics is selected, and the liquid seal cassette 42 and the integrally vulcanized molded product 40 of the main rubber elastic body 16 are combined. By manufacturing the engine mount 10, the vibration isolation characteristics of the engine mount 10 can be tuned. Further, instead of preparing a plurality of types of liquid seal cassettes 42, a plurality of types of integral vulcanization molded products 40 of the main rubber elastic body 16 having different shapes and sizes of the rubber protrusions 36 are prepared. From the integrally vulcanized molded product 40 of the main rubber elastic body 16, the integrally vulcanized molded product 40 of the main rubber elastic body 16 necessary for the required vibration-proof characteristics is selected, and the integrated vulcanization of the main rubber elastic body 16 is selected. The vibration isolation characteristics of the engine mount 10 may be tuned by manufacturing the engine mount 10 by combining the molded product 40 and the liquid seal cassette 42.

  On the other hand, when medium to high frequency small amplitude vibration such as idling vibration is input between the first mounting bracket 12 and the second mounting bracket 14 when the automobile is stopped, the pressure fluctuation exerted in the pressure receiving chamber 86 is changed. As a result, the movable rubber film 74 is slightly deformed. Then, the hydraulic pressure in the pressure receiving chamber 86 is transmitted to the equilibrium chamber 88 side by minute deformation of the movable rubber film 74. Such an anti-vibration effect such as a low dynamic spring effect based on the hydraulic pressure absorbing action by the minute elastic deformation of the movable rubber film 74 is effectively exhibited.

  Further, an impact vibration load is input between the first mounting bracket 12 and the second mounting bracket 14 due to, for example, climbing over a step during driving of the automobile, so that the first mounting bracket 12 is attached to the second mounting bracket 12. When the first and second mounting brackets 12 and 14 are relatively displaced in the axial direction relative to the bracket 14 in the axially upper direction, the rubber elasticity of the main body is increased. The body 16 is elastically deformed so as to be lifted upward relative to the second mounting bracket 14, and the lower end surface of the main rubber elastic body 16 is displaced upward.

  In this case, the main rubber elastic body 16 and the liquid seal cassette 42 are formed as separate bodies and are superposed on each other in a non-adhesive manner. Therefore, when the main rubber elastic body 16 is displaced upward, the main rubber elastic body 16 is elastic. The central portion of the upper bottom 30 of the central recess 30 formed in the body 16 is separated from the central portion of the upper bottom wall 54 of the elastic rubber wall 52 of the liquid seal cassette 42 and formed at the outer peripheral edge of the main rubber elastic body 16. The stepped surface 34 is separated from the cylindrical wall 56 in the elastic rubber wall 52 of the liquid seal cassette 42, and the rubber protrusion 36 provided on the main rubber elastic body 16 is further in the elastic rubber wall 52 of the liquid seal cassette 42. It is separated from the tapered portion 58 of the upper base 54. Thus, the overlapping surfaces of the main rubber elastic body 16 and the elastic rubber wall 52 are communicated with the atmosphere through the atmosphere communication hole 100. As a result, when the main rubber elastic body 16 is displaced upward and separated from the elastic rubber wall 52, the pressure between the overlapping surfaces of the main rubber elastic body 16 and the elastic rubber wall 52 decreases and the elastic rubber wall 52. Is prevented from being displaced by suction toward the main rubber elastic body 16 side. Therefore, even when the main rubber elastic body 16 is greatly displaced upward by the input of shocking vibration load, the volume expansion of the pressure receiving chamber 86 due to the deformation of a part of the wall is advantageously prevented. Thus, the pressure drop in the pressure receiving chamber 86 is limited. As a result, it is possible to reduce or avoid the generation of bubbles due to the cavitation phenomenon accompanying the pressure drop in the pressure receiving chamber 86, and to advantageously prevent abnormal noise and vibration that are thought to occur when the bubbles collapse. I can do it.

  In the present embodiment, the main rubber elastic body 16 and the elastic rubber wall 52 are pressed against each other in the axial direction, and the contact force between the main rubber elastic body 16 and the elastic rubber wall 52 is appropriately adjusted so that cavitation occurs. When a shocking vibration load of a problem level is input, the contact state between the main rubber elastic body 16 and the elastic rubber wall 52 is released.

  In this embodiment, the outer cylinder fitting 22 is vulcanized and bonded to the outer peripheral surface of the main rubber elastic body 16, and the housing metal fitting 44 is press-fitted and fixed to the outer cylinder fitting 22 fixed to the main rubber elastic body 16. Thus, the liquid seal cassette 42 is assembled to the integrally vulcanized molded product 40 of the main rubber elastic body 16. Thus, by attaching the outer cylinder fitting 22 to the main rubber elastic body 16 in advance by vulcanization, the liquid seal cassette 42 can be easily mounted on the main rubber elastic body 16 side.

  Further, in the present embodiment, the atmosphere communication hole 100 penetrating the outer cylindrical fitting 22 is provided so as to communicate between the contact surfaces of the main rubber elastic body 16 and the cylindrical wall 56 of the elastic rubber wall 52. Thus, when the housing fitting 44 is press-fitted into the outer tubular fitting 22, the air existing between the housing fitting 44 and the main rubber elastic body 16 is discharged to the outside through the atmosphere communication hole 100. Therefore, it is possible to prevent the spring action based on the elasticity of air and to assemble the liquid seal cassette 42 at a predetermined position with respect to the integrally vulcanized molded product 40 of the main rubber elastic body 16. Therefore, both the above-described anti-vibration effect at the time of input of vibration-proof target vibration and the effect of suppressing cavitation noise at the time of input of shocking vibration can be exhibited effectively.

  The main rubber elastic body 16 and the elastic rubber wall 52 are formed as separate members. In the present embodiment, the main rubber elastic body 16 and the elastic rubber wall 52 are formed of rubber elastic bodies having different compositions. Therefore, the characteristics such as load resistance performance and damping performance required for the main rubber elastic body 16 and the characteristics such as erosion resistance performance and sealing performance for the sealed fluid required for the elastic rubber wall 52 are both advanced. Can be realized.

  Further, in this embodiment, the liquid seal cassette 42 is separate from the integrally vulcanized molded product 40 of the main rubber elastic body 16, and the housing metal fitting 44 is subjected to diameter reduction processing, whereby the housing metal fitting is obtained. A partition member 68 and a diaphragm 62 are fixed to 44. On the other hand, the outer cylinder fitting 22, which is a separate member from the housing fitting 44, is vulcanized and bonded to the main rubber elastic body 16. The rubber elastic body 16 is pre-compressed. Therefore, the diameter reduction amount of the outer metal fitting 22 and the diameter reduction amount of the housing metal fitting 44 can be made different so that the main rubber elastic body 16 is sufficiently pre-compressed without deforming the housing metal fitting 44 more than necessary. As a result, the load bearing performance required for the main rubber elastic body 16 can be realized to a high degree.

  Incidentally, the respective peak values of the dynamic spring constant and the damping coefficient when an excitation force was applied to the first mounting bracket 12 constituting the engine mount 10 of the present embodiment were measured. At that time, the excitation force was measured for each of amplitudes of ± 0.1 mm, ± 0.5 mm, ± 1.0 mm, and ± 2.0 mm. The initial load was 1200N. For comparison, a similar test was performed on an engine mount (hereinafter referred to as an engine mount having a conventional structure) provided with the main rubber elastic body 16 in which the rubber protrusions 36 are not provided. These results are shown in Table 1. The engine mount 10 of the present embodiment was subjected to frequency sweep excitation with an excitation force having an amplitude of ± 0.5 mm, and the frequency characteristics of the dynamic spring constant and the damping coefficient were measured. The initial load was 1200N. For comparison, a similar test was performed on a conventional engine mount. These results are shown in FIG.

  As is apparent from Table 1 and FIG. 4, it is confirmed that the engine mount 10 provided with the rubber protrusion 36 has a larger damping coefficient and dynamic spring constant than the engine mount having the conventional structure. It was.

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

  For example, in the embodiment, the rubber protrusion 36 may be divided in the circumferential direction. In the embodiment, two or more rubber protrusions 36 may be formed.

  Further, the shape of the abutting protrusion is not limited to the shape of the above-described embodiment. For example, as shown in FIG. 5, the base rubber provided at the center of the upper bottom surface of the central recess 30. It is also possible to employ an abutting protrusion 106 having an annular protruding rubber 104 protruding downward from the lower surface of 102. In this case, it is possible to adjust the piston efficiency while suppressing adverse effects on the spring characteristics of the main rubber elastic body 16. In addition, the durability of the contact protrusion 106 can be improved. In order to facilitate understanding, in FIG. 5, the parts having the same structure as in the above embodiment are denoted by the same reference numerals as those in the above embodiment.

  Furthermore, in the above-described embodiment, the rubber protrusion 36 of the main rubber elastic body 16 is brought into contact with the tapered portion 58 of the elastic rubber wall 52 in both the engine mount 10 alone and the mounted state of the engine mount 10. However, for example, in the engine mount 10 alone, the rubber protrusion 36 of the main rubber elastic body 16 is not brought into contact with the tapered portion 58 of the elastic rubber wall 52. The rubber protrusion 36 of the body 16 may be brought into contact with the taper portion 58 of the elastic rubber wall 52, or the main rubber elastic body in either the engine mount 10 alone or the engine mount 10 mounted state. The 16 rubber protrusions 36 are not brought into contact with the tapered portion 58 of the elastic rubber wall 52, and the main rubber elastic body 16 is at the time of vibration input. Tapered portion 58 of the rubber projection 36 and the elastic rubber wall 52 may be caused to abut.

  In the embodiment, the air communication hole 100 is not necessarily required.

  Further, in the embodiment, the contact protrusion is provided on the main rubber elastic body, but the contact protrusion may be provided on the elastic rubber wall, or the main rubber elastic body and the elastic rubber wall may be provided. Both may be provided with contact protrusions.

  Moreover, in the said embodiment, the concave groove-shaped air path extended in a radial direction may be formed in at least one place on the periphery of the rubber protrusion 36. FIG. In this case, it is possible to prevent abnormal noise due to air leakage due to compression of air existing in the gaps 96 and 98. Furthermore, it is desirable that the concave air passages communicate with each other. At that time, for example, the atmosphere communication hole 100 can be used.

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

The longitudinal cross-sectional view which shows the engine mount for motor vehicles as one Embodiment of this invention. 1. An integrally vulcanized molded product of a main rubber elastic body constituting the engine mount shown in FIG. The liquid seal cassette which comprises the engine mount shown by FIG. The graph which shows the test result of the vibration proof characteristic of the engine mount shown by FIG. The longitudinal cross-sectional view for demonstrating the shape of the contact protrusion which can be employ | adopted in this invention.

Explanation of symbols

10: automotive engine mount, 12: first mounting bracket, 14: second mounting bracket, 16: main rubber elastic body, 22: outer cylinder bracket, 36: rubber protrusion, 40: integral vulcanization molded product, 42: liquid seal cassette, 44: housing fitting, 52: elastic rubber wall, 62: diaphragm, 66: fluid sealing area, 68: partition member, 86: pressure receiving chamber, 88: equilibrium chamber, 90: orifice passage

Claims (6)

A vibration isolator that is mounted between members constituting a vibration transmission system,
One opening of the cylindrical housing is closed with an elastic rubber wall, and the other opening of the cylindrical housing is closed with a flexible film, and between the elastic rubber wall and the facing surface of the flexible film A fluid chamber in which an incompressible fluid is sealed is formed, and a partition member that is disposed in the fluid chamber and bisects the fluid chamber is supported by the cylindrical housing, and sandwiches the partition member. A main liquid chamber in which a part of the wall is formed of the elastic rubber wall is formed on the side of the wall, and a part of the wall is formed of the flexible film on the other side across the partition member. A liquid sealing unit having a structure in which the main liquid chamber and the sub liquid chamber are communicated with each other through an orifice passage,
In the main rubber elastic body formed separately from the liquid seal unit, a first attachment member attached to one member constituting the vibration transmission system is provided at a central portion of one end portion in the main vibration input direction. A liquid sealing unit is disposed on the other end side of the main rubber elastic body in the main vibration input direction, and the elastic rubber wall of the liquid sealing unit is the main vibration in the main rubber elastic body. The abutment provided so as to be opposed to the other end face in the input direction so that the elastic rubber wall and the main rubber elastic body protrude from at least one side of the elastic rubber wall and the main rubber elastic body. The other member constituting the vibration transmission system, which is brought into contact with the protrusion, and the cylindrical housing of the liquid sealing unit is fixedly attached to the outer peripheral surface of the main rubber elastic body. The second mounting member attached is configured to include a cylindrical housing vibration damping device according to claim.   The vibration isolator according to claim 1, wherein the contact protrusion is formed over the entire circumference in a circumferential direction around the elastic central axis of the main rubber elastic body.   The vibration isolator according to claim 1 or 2, wherein the contact protrusion is a rubber protrusion integrally formed with the elastic rubber wall or the main rubber elastic body.   The main rubber elastic body has a truncated cone shape, and the first attachment member is fixed to the small diameter side end surface of the main rubber elastic body, while the large diameter side end of the main rubber elastic body An inner peripheral surface of the cylindrical portion of the second mounting bracket is fixed to the outer peripheral surface of the second mounting bracket, and the cylindrical housing of the liquid sealing unit is further connected to the cylindrical portion of the second mounting bracket. The vibration isolator according to any one of claims 1 to 3, wherein the rubber elastic body is fitted and fixed to the large diameter side end surface of the main rubber elastic body so as to overlap the elastic rubber wall of the liquid sealing unit. apparatus. A method for manufacturing a vibration isolator according to any one of claims 1 to 4,
5. The system according to claim 1, wherein a plurality of types of main rubber elastic bodies are prepared, and the main rubber elastic bodies selected from the plurality of main rubber elastic bodies are combined with the liquid seal unit. A method for manufacturing an anti-vibration device is provided. A method for manufacturing a vibration isolator according to any one of claims 1 to 4,
5. The prevention according to claim 1, wherein a plurality of types of liquid sealing units are prepared, and the liquid sealing unit selected from the plurality of types of liquid sealing units is combined with the main rubber elastic body. A method of manufacturing a vibration isolator, comprising manufacturing a vibration isolator.

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