Vibration isolation system

Abstract

To provide a novel vibration isolation system which can be mounted to a vehicle by arbitrarily selecting either of a negative pressure type and a non-negative pressure type by using a fluid sealing type vibration isolation device having a common structure.SOLUTION: In a vibration isolation system 10 using fluid sealing type vibration isolation devices 12, 13, partial wall parts of fluid chambers 20 of both the fluid sealing type vibration isolation devices 12, 13 are constituted of membranes 64, action air chambers 68 are formed at sides opposite to the fluid chambers 20 with respect to the membranes 64, a selector valve 90 having a first port 92 and a second port 94, and making the ports 92, 94 communicate with the action air chambers 68 by selectively switching them is arranged, and the first port 92 has an atmosphere release structure, and the first port 92 can select a block structure to which a cap 102 is attached in each of the fluid sealing type vibration isolation devices 12, 13, and which is sealed by the cap 102, and a suction structure which is connected to a negative pressure source 106, and in which negative pressure is applied to the action air chambers 68.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to an anti-vibration system using a number of different fluid-filled anti-vibration devices with fluid sealed inside, and in particular to a vibration-proof system in which each fluid-filled anti-vibration device has an active air chamber and a switching valve communicating with the active air chamber. [Background technology]

[0002] Conventionally, as vibration isolation devices such as vibration isolation supports and vibration isolation connectors interposed between members constituting a vibration transmission system, there have been known fluid-filled vibration isolation devices that obtain vibration isolation effects based on flow actions such as resonance actions of a non-compressible fluid filled inside. Such a fluid-filled vibration isolation device has been proposed, for example, in JP 2007-162876 A (Patent Document 1).

[0003] In particular, the fluid-filled vibration-damping device described in Patent Document 1 is equipped with an application air chamber and a switching valve that communicates with the application air chamber, and is configured as a negative pressure type fluid-filled vibration-damping device in which the application air chamber is selectively connected to the atmosphere or a predetermined negative pressure source by switching the switching valve. In such a fluid-filled vibration-damping device, the vibration-damping characteristics of the vibration-damping device are changed by switching the switching valve, so that the vibration-damping effect is exerted against vibrations of a plurality of different frequencies. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2007-162876 A Summary of the Invention [Problem to be solved by the invention]

[0005] Incidentally, in a vehicle using a fluid-filled vibration-damping device such as that described in Patent Document 1, for example, a switching valve may be switched during idling to connect the working air chamber to a negative pressure source, thereby suppressing idling vibrations by a vibration-damping mechanism provided with an orifice passage or the like tuned to the frequency of idling vibrations, etc., in the fluid-filled vibration-damping device. The negative pressure source that is connected to such working air chamber may be, for example, the engine intake negative pressure.

[0006] However, in recent years, the number of vehicles equipped with direct injection engines and vehicles with idling stop systems has increased, and there are cases where it is not possible to use the engine intake negative pressure as a negative pressure source. In such cases, it is possible to use a non-negative pressure type vibration isolation device, but in other cases, negative pressure type vibration isolation devices are still often used, so from the standpoint of cost, environmental aspects, etc., there has been a demand for a vibration isolation system that allows a fluid-filled type vibration isolation device to be used in both the negative pressure type and the non-negative pressure type.

[0007] Furthermore, when constructing a vibration isolation system using multiple fluid-filled vibration isolation devices in this manner, it is necessary to tune the vibration isolation characteristics of the working air chamber in each fluid-filled vibration isolation device to the desired frequency, and there was a demand for a vibration isolation system in which the spring characteristics can be tuned more easily.

[0008] The present invention has been made against the background of the above-mentioned circumstances, and its problem to be solved is to provide a new vibration isolation system that uses a fluid-filled vibration isolation device of a common structure and can be installed in a vehicle by selecting either a negative pressure type or a non-negative pressure type.

[0009] Another problem to be solved by the present invention is to provide a novel vibration isolation system that allows for easy tuning of the spring characteristics of each working air chamber in a plurality of fluid-filled type vibration isolation devices. [Means for solving the problem]

[0010] The following describes preferred embodiments for understanding the present invention, but the embodiments described below are merely illustrative and may be combined with one another as appropriate, and the multiple components described in each embodiment may be recognized and used independently as far as possible, and may also be combined with any of the components described in another embodiment as appropriate. As a result, the present invention is not limited to the embodiments described below, and various other embodiments may be realized.

[0011] The first aspect is a vibration-damping system using a fluid-filled vibration-damping device in which a first mounting member and a second mounting member are connected by a main rubber elastic body and a fluid chamber is formed inside, and in each of the fluid-filled vibration-damping devices, a part of the wall of the fluid chamber is constructed of a membrane and an working air chamber is formed on the opposite side of the membrane to the fluid chamber, and a switching valve is provided which has a first port and a second port and selectively switches the ports to communicate with the working air chamber, and in each of the fluid-filled vibration-damping devices, the first port is of an atmospheric open structure, and in each of the fluid-filled vibration-damping devices, the second port is selectable between a blocking structure in which a cap is attached and sealed by the cap, and a suction structure in which the second port is connected to a negative pressure source and negative pressure is applied to the working air chamber.

[0012] According to this aspect, it is possible to arbitrarily select either the negative pressure type or the non-negative pressure type using a fluid-filled vibration-proof device of a common structure. That is, when the second port of the switching valve is connected to a negative pressure source (for example, engine intake negative pressure) and has a suction structure in which negative pressure is applied to the working air chamber, this fluid-filled vibration-proof device is a negative pressure type fluid-filled vibration-proof device similar to the conventional one. On the other hand, when a cap is attached to the second port of the switching valve and the working air chamber is sealed by the cap, this fluid-filled vibration-proof device is a non-negative pressure type fluid-filled vibration-proof device that does not have a negative pressure source (for example, engine intake negative pressure). In this way, by making the second port of the switching valve either the suction structure or the blocking structure, it is possible to arbitrarily select either the negative pressure type or the non-negative pressure type, and in the vibration-proof system of this aspect, not only the fluid-filled vibration-proof device but also the switching valve are of a common structure. In other words, in the vibration isolation system of this embodiment, a fluid-filled vibration isolation device having a common structure up to the switching valve can be applied to vehicles with a negative pressure source (e.g., engine intake negative pressure) and vehicles without a negative pressure source (e.g., engine intake negative pressure).

[0013] In a second aspect, in the vibration isolation system according to the first aspect, a switching control device is provided that controls the switching of the switching valve, and the switching control device switches the switching valve with the same control in each of the fluid-filled vibration isolation devices.

[0014] According to the present embodiment, there is no need to change the switching control device of the switching valve between a negative pressure type fluid-filled vibration damping device (i.e., the second port has a suction structure) and a non-negative pressure type fluid-filled vibration damping device (i.e., the second port has a blocking structure), and the desired characteristics can be obtained with a common control mode both when the cap is attached and when a negative pressure source is connected.

[0015] The third aspect is a vibration isolation system using a fluid-filled vibration isolation device in which a first mounting member and a second mounting member are connected by a main rubber elastic body and a fluid chamber is formed inside, and in each of the fluid-filled vibration isolation devices, a part of the wall of the fluid chamber is constructed of a membrane, and an working air chamber is formed on the opposite side of the membrane to the fluid chamber, and a switching valve is provided which has a first port and a second port and selectively switches these ports to communicate with the working air chamber, and in each of the fluid-filled type vibration isolation devices, the first port is open to the atmosphere, and in each of the fluid-filled type vibration isolation devices, a blocking tube is attached to the second port, and the end opening of the blocking tube on the opposite side to the second port is blocked, and in each of the fluid-filled type vibration isolation devices, the length of the blocking tube is adjusted individually according to the required spring characteristics of the working air chamber.

[0016] According to this aspect, in a fluid-filled vibration damping device in which a blocking tube is attached to the second port of the switching valve, when the switching valve is switched to connect the working air chamber to the second port, the internal space of the working air chamber, the second port, and the blocking tube become one space, so that the internal volume of this one space can be adjusted by adjusting the length of the blocking tube, and the characteristics when the working air chamber is connected to the second port can be easily tuned by utilizing the compressibility of the air in the blocking tube.

[0017] In a fourth aspect, in the vibration isolation system according to any one of the first to third aspects, the first port is equipped with an open tube in any of the fluid-filled vibration isolation devices, and the length of the open tube in each of the fluid-filled vibration isolation devices is adjusted individually according to the required spring characteristics of the working air chamber.

[0018] According to this aspect, in a fluid-filled vibration damping device in which an open tube is attached to a first port in a switching valve, when the switching valve is switched to connect the working air chamber to the first port, the internal space of the working air chamber, the first port, and the open tube become one space, and therefore the internal volume of this one space can be adjusted by adjusting the length of the open tube, and the characteristics when the working air chamber is connected to the first port can be easily tuned by using the resonance phenomenon of the air in the open tube. Effect of the Invention

[0019] According to the present invention, it is possible to provide a novel vibration isolation system that uses a fluid-filled vibration isolation device of a common structure and can be installed in a vehicle by selecting either a negative pressure type or a non-negative pressure type.

[0020] According to another aspect of the present invention, it is possible to provide a novel vibration isolation system that allows for easy tuning of the spring characteristics of each working air chamber in a plurality of fluid-filled type vibration isolation devices. [Brief description of the drawings]

[0021] [Figure 1] FIG. 1 is an explanatory diagram for explaining a model of a vibration isolation system according to an embodiment of the present invention; [Diagram 2] FIG. 2 is a vertical cross-sectional view of a fluid-filled type vibration isolation device constituting the vibration isolation system shown in FIG. 1, showing a fluid-filled type vibration isolation device having a blocking structure in which a second port is blocked by a cap. [Diagram 3] FIG. 2 is a vertical cross-sectional view of a fluid-filled type vibration isolation device constituting the vibration isolation system shown in FIG. 1, showing a fluid-filled type vibration isolation device having a suction structure in which a negative pressure source is connected to a second port. [Figure 4] Graph showing the relationship between the length of the tube and the spring characteristics in the working air chamber in the fluid-filled vibration isolation device constituting the vibration isolation system shown in FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0022] In order to clarify the present invention more specifically, embodiments of the present invention will be described in detail below with reference to the drawings.

[0023] First, FIG. 1 shows an anti-vibration system 10 according to an embodiment of the present invention. This anti-vibration system 10 includes an engine mount 12 (12') which is a non-negative pressure type fluid-filled anti-vibration device shown in FIG. 2, and an engine mount 13 which is a negative pressure type fluid-filled anti-vibration device shown in FIG. 3. Many parts of these engine mounts 12 (12'), 13 have a common structure, and in the following description, the common structure of both engine mounts 12 (12'), 13 will be described first. Both engine mounts 12 (12'), 13 have a basic structure in which a first mounting member 14 and a second mounting member 16 are connected by a main rubber elastic body 18, and a fluid chamber 20 is formed inside the engine mount 12. Note that although both engine mounts 12 and 12' are non-negative pressure types, the length dimensions of an open tube 98 and a closed tube 100, which will be described later, are different from each other. In the following description, unless otherwise specified, the vertical direction refers to the vertical direction in FIG. 2, which is the mount axial direction.

[0024] More specifically, the first mounting member 14 is generally columnar and extends vertically as a whole, and in this embodiment in particular, the lower portion of the first mounting member 14 is generally cup-shaped and opens downward. Meanwhile, the upper portion of the first mounting member 14 is provided with bolt holes 22 that open upward and into which bolts (not shown) are fastened, and the first mounting member 14 integrally comprises a generally cup-shaped lower portion and a generally cylindrical upper portion having the bolt holes 22.

[0025] The second mounting member 16 has a generally stepped cylindrical shape overall, with a step portion 24 formed in the axial middle portion sandwiching a large-diameter cylindrical portion 26 at the top and a small-diameter cylindrical portion 28 at the bottom. A generally annular fitting projection 29 that projects inward is formed at the lower end of the small-diameter cylindrical portion 28. The first mounting member 14 is disposed at a distance from the upper opening side of the second mounting member 16, with the central axes of both members 14, 16 positioned generally on the same line, and a main rubber elastic body 18 is disposed between the first mounting member 14 and the second mounting member 16.

[0026] The main rubber elastic body 18 has a generally truncated cone shape, and the lower portion of the first mounting member 14 is fixed to its small diameter end face in a state in which the lower portion is substantially entirely embedded. The outer peripheral surface of the large diameter end of the main rubber elastic body 18 is fixed to the inner peripheral surfaces of the large diameter tubular portion 26 and the stepped portion 24 of the second mounting member 16. In this embodiment, the main rubber elastic body 18 is formed as an integrally vulcanization molded product including the first mounting member 14 and the second mounting member 16. As a result, the first mounting member 14 and the second mounting member 16 are elastically connected by the main rubber elastic body 18, and the upper opening of the large diameter tubular portion 26 of the second mounting member 16 is fluid-tightly closed by the main rubber elastic body 18.

[0027] A large diameter recess 30 that opens downward is formed in the large diameter end face of the main rubber elastic body 18. Furthermore, a seal rubber layer 32 that is formed integrally with the main rubber elastic body 18 is fixed to the inner circumferential surface of the small diameter cylindrical portion 28 of the second mounting member 16 with a substantially constant thickness dimension.

[0028] A partition member 34 is attached to the integrally vulcanized molded product of the main rubber elastic body 18 equipped with the first and second mounting members 14, 16 from the lower opening side of the second mounting member 16. The partition member 34 in this embodiment is generally cup-shaped opening downward as a whole, and is made of hard synthetic resin. Particularly in this embodiment, the partition member 34 is composed of an upper cover member 36 and a lower partition member main body 38.

[0029] The partition member main body 38 has an outer diameter smaller than the inner diameter of the small diameter cylindrical portion 28 of the second mounting member 16, and a central recess 40 that opens downward is formed in the central portion of the underside of the partition member main body 38. A ring-shaped step surface 42 that expands in the axis-perpendicular direction is formed on the inner circumferential surface of the peripheral wall of this central recess 40, located in the middle portion in the axial direction (depth direction). As a result, the inner diameter dimension of the central recess 40 above the step surface 42 is smaller than the inner diameter dimension below the step surface 42.

[0030] A circumferential groove 44 that opens onto the outer circumferential surface and extends a predetermined length in the circumferential direction is formed in the peripheral wall of the partition member main body 38. One end of the circumferential groove 44 opens upward through a communication window 45 provided in the upper end of the partition member main body 38, and the other end of the circumferential groove 44 opens downward through a communication window (not shown) provided in the lower end of the partition member main body 38.

[0031] Furthermore, an annular protrusion 46 having a circular ring shape that protrudes upward is provided on the upper end surface of the peripheral wall of the partition member main body 38. As a result, an upper recess that opens upward is formed on the inner peripheral side of the annular protrusion 46 on the upper end surface of the partition member main body 38. The inner diameter dimension of the annular protrusion 46 is approximately equal to the inner diameter dimension above the step surface 42 of the central recess 40. The upper opening of this upper recess is covered by the cover member 36 that is superimposed on the partition member main body 38 from above.

[0032] The lid member 36 is generally dish-shaped and opens downward, and is placed on the upper end surface of the annular protrusion 46 of the partition member body 38 so that the upper opening of the upper recess and the lower opening of the lid member 36 are butted against each other. The method of fastening the lid member 36 to the partition member body 38 is not limited, and they may be fastened by welding, adhesive, or the like. A constrained arrangement region 48 is formed by the space between the lid member 36 and the upper recess of the partition member body 38.

[0033] In the partition member main body 38 and the cover member 36, a plurality of through holes 50 are formed in the portions constituting the upper and lower walls of the restrained installation area 48, penetrating in the vertical direction. Through each of these through holes 50, the internal space of the restrained installation area 48 is communicated with the external spaces on both the upper and lower sides in the vertical direction. A movable plate 52 made of an elastic material such as rubber is housed and disposed in the restrained installation area 48. The movable plate 52 has a thin, generally circular plate shape overall, and is located in the center of the restrained installation area 48. The vertical dimension of the movable plate 52 is smaller than the distance between the opposing surfaces of the upper and lower walls of the restrained installation area 48, so that the movable plate 52 is vertically displaceable within the restrained installation area 48.

[0034] The partition member 34, which is made up of the cover member 36 and the partition member main body 38, is fitted with the fixing member 54 from below in the axial direction. The fixing member 54 is generally disk-shaped as a whole, and is made of hard synthetic resin. A lower recess 56 that opens downward is provided in the central portion of the lower surface of the fixing member 54. A central protrusion 58 that protrudes upward is integrally formed in the central portion of the fixing member 54. A generally circular recess that opens upward is formed in the upper end surface of the central protrusion 58. A fitting groove 59 that extends annularly over the entire circumference in the circumferential direction is provided in the outer peripheral surface at the protruding base end (lower end) of the central protrusion 58.

[0035] The upper end surface of the fixing member 54 on the outer circumferential side of the central projection 58 is a generally annular flat surface that extends in the axis-perpendicular direction, and a communication hole (not shown) that penetrates in the vertical direction is formed in the outer circumferential portion of the fixing member 54. This communication hole is formed in a position corresponding to the communication window in the other end of the circumferential groove 44, and communicates between the upper side and the lower side (lower recess 56) of the fixing member 54. Furthermore, an upper fitting groove 60 and a lower fitting groove 62 that extend over the entire circumferential direction are formed in the upper end portion and the lower end portion of the outer circumferential surface of the fixing member 54, respectively.

[0036] The fixing member 54 is fixed to the partition member 34, for example, by fitting together the projections and recesses provided on the fixing member 54. These projections and recesses are formed, for example, with a certain circumferential length. This allows the upper end surface of the fixing member 54 and the lower end surface of the partition member 34 to overlap with almost no gap between them.

[0037] A membrane 64 is attached to the central projection 58 of the fixing member 54. The membrane 64 is generally thin and generally disk-shaped, and is made of an elastic material such as rubber. A plurality of irregularities, grooves, protrusions, etc. are formed on both sides of the membrane 64, and the thickness dimension varies in the circumferential direction. A generally cylindrical fitting ring 66 is fixed to the outer peripheral end of the membrane 64, and in this embodiment, the membrane 64 is formed as an integrally molded product including the fitting ring 66. The lower end of the fitting ring 66 is bent toward the inner peripheral side, and the lower end of the fitting ring 66 is inserted into the fitting groove 59 of the central projection 58, so that the membrane 64 is attached to the fixing member 54 so as to cover the upper opening of the central projection 58.

[0038] A working air chamber 68 is formed between the bottoms of the central projections 58 and the membrane 64. An air passage 70 is formed penetrating the fixed member 54. One end of the air passage 70 opens into the upper surface of the central projection 58 and is connected to the working air chamber 68, and the other end of the air passage 70 opens into the outer circumferential surface of the fixed member 54. The other end of the air passage 70 is formed as a substantially cylindrical port portion 72, which protrudes outward from the outer circumferential surface of the fixed member 54.

[0039] When the fixing member 54 with the membrane 64 attached to the central protrusion 58 is attached to the partition member 34 from below, the outer peripheral end of the membrane 64 and the upper end of the fitting ring 66 are superimposed on the step surface 42 in the central recess 40 provided below the partition member 34. As a result, the central recess 40 in the partition member 34, which opens downward, is covered with the membrane 64.

[0040] The assembly of the fixing member 54 and the partition member 34 is inserted from the lower opening of the second mounting member 16, and the fitting projection 29 at the lower end of the second mounting member 16 is fitted into the upper fitting groove 60 of the fixing member 54, thereby assembling the fixing member 54 and the partition member 34 to the second mounting member 16. As a result, the second mounting member 16 is fitted and fixed to the upper end portion of the fixing member 54.

[0041] Furthermore, a diaphragm 74 is attached to the lower end of the fixed member 54 exposed from the lower end of the second mounting member 16. The diaphragm 74 is generally in the shape of a thin disk, and is made of an elastic material such as rubber, so that it can be easily flexed and deformed. A substantially cylindrical fixing metal fitting 76 is fixed to the outer peripheral end of the diaphragm 74, and a substantially annular fitting protrusion 78 that protrudes to the inner peripheral side is formed at the upper end of the fixing metal fitting 76. The fixing metal fitting 76 is fitted onto the fixed member 54, and the fitting protrusion 78 is inserted into the lower fitting groove 62 of the fixed member 54, so that the diaphragm 74 is attached below the fixed member 54. As a result, the opening of the lower recess 56 of the fixed member 54 is covered fluid-tightly by the diaphragm 74. In short, the lower opening of the second mounting member 16 is covered by the diaphragm 74 via the fixing member 54, and the partition member 34 and the fixing member 54 are arranged between the axially opposing surfaces of the main rubber elastic body 18 and the diaphragm 74.

[0042] In this way, a fluid chamber 20 that is sealed off from the outside space is formed between the opposing surfaces of the main rubber elastic body 18 and the diaphragm 74, and a non-compressible fluid is sealed in the fluid chamber 20. The sealed fluid may be, for example, water, alkylene glycol, polyalkylene glycol, silicone oil, etc., but in order to effectively obtain vibration-damping effects based on flow effects such as the resonance effect of the fluid, it is preferable to use a low-viscosity fluid of 0.1 Pa s or less.

[0043] As described above, the partition member 34 and the fixed member 54 are disposed inside the fluid chamber 20 so as to extend in the direction perpendicular to the axis, and the fluid chamber 20 is divided into two halves in the axial direction, up and down, by the partition member 34 and the fixed member 54. Above the partition member 34 and the fixed member 54 in the fluid chamber 20, a part of the wall is formed by the main rubber elastic body 18, forming a main fluid chamber 80 in which pressure fluctuations occur based on elastic deformation of the main rubber elastic body 18 when vibration is input between the first mounting member 14 and the second mounting member 16. Meanwhile, below the partition member 34 and the fixed member 54 in the fluid chamber 20, a part of the wall is formed by the diaphragm 74, forming an equilibrium chamber 82 in which volume changes are easily permitted by deformation of the diaphragm 74.

[0044] As described above, the lower opening of the central recess 40 in the partition member body 38 is covered with the membrane 64, and the auxiliary liquid chamber 84 is formed between the partition member body 38 and the membrane 64. A non-compressible fluid is sealed in this auxiliary liquid chamber 84, similar to the main liquid chamber 80 and the equilibrium chamber 82, and a part of the fluid chamber 20 is formed by the auxiliary liquid chamber 84. As a result, a part of the wall of the fluid chamber 20 is formed by the membrane 64. The auxiliary liquid chamber 84 is formed above the membrane 64, and the working air chamber 68 is formed below it; in other words, the working air chamber 68 is formed on the opposite side of the membrane 64 to the fluid chamber 20 (auxiliary liquid chamber 84).

[0045] Furthermore, the primary liquid chamber 80 and the auxiliary liquid chamber 84 are vertically separated by a constrained arrangement region 48 in the partition member 34, and a movable plate 52 is arranged in the constrained arrangement region 48 in a state in which it can be displaced a predetermined amount vertically. The pressures of the primary liquid chamber 80 and the auxiliary liquid chamber 84 are respectively exerted on the upper and lower surfaces of this movable plate 52 through a plurality of through holes 50. When vibration is input, the pressure fluctuations of the primary liquid chamber 80 are released to the auxiliary liquid chamber 84 based on fluctuations in the relative pressure difference between the primary liquid chamber 80 and the auxiliary liquid chamber 84.

[0046] The partition member 34 and the fixing member 54 are then assembled to the second mounting member 16, and the outer peripheral opening of the circumferential groove 44 in the partition member body 38 is fluid-tightly covered by the small diameter cylindrical portion 28 of the second mounting member 16 via the seal rubber layer 32, thereby forming an orifice passage 86. One end of the orifice passage 86 is connected to the primary liquid chamber 80 through the communication window 45 of the partition member body 38. The other end of the orifice passage 86 is connected to the equilibrium chamber 82 through a communication window and a communication hole (not shown) in the partition member body 38 and the fixing member 54. As a result, the primary liquid chamber 80 and the equilibrium chamber 82 are mutually connected by the orifice passage 86, and fluid flow is permitted between the two chambers 80, 82 through the orifice passage 86. This orifice passage 86 is tuned so that the resonant frequency of the fluid flowing through the orifice passage 86 provides an effective vibration-damping effect (vibration isolation effect based on low dynamic spring characteristics) against vibrations in a frequency range (e.g., about several tens of Hz) corresponding to idling vibrations, etc., based on the resonant action of the fluid.

[0047] In the engine mount 12 (or engine mount 12', 13) constructed as described above, the first mounting member 14 is fixed to a member on the power unit side by bolts (not shown) fastened to bolt holes 22, and the large diameter cylindrical portion 26 of the second mounting member 16 is fixed to a bracket (not shown) and fixed to a member on the vehicle body side. In this way, the engine mount 12 (or engine mount 12', 13) is attached between the power unit and the vehicle body, and the power unit is supported in a vibration-proof manner relative to the vehicle body.

[0048] Here, an air pipe 88 is connected to the port portion 72 in the fixed member 54, and the port portion 72, the air passage 70, and the internal space of the working air chamber 68 are connected to a changeover valve 90 via the air pipe 88. The changeover valve 90 is a three-way valve provided with a first port 92 and a second port 94, and switching is controlled by a switching control device 96 provided in the vehicle, so that the first port 92 and the second port 94 are alternatively selected to communicate with the port portion 72 and the air pipe 88. In other words, the changeover valve 90 is also an electromagnetically switched solenoid valve, and the changeover valve 90 selectively switches between the first port 92 and the second port 94 to communicate with the working air chamber 68.

[0049] The switching control device 96 receives necessary information from various sensors mounted on the vehicle, such as the vehicle's speed, engine speed, reduction gear selection position, throttle opening, and other information that indicates the vehicle's state, and switches the switching valve 90 using microcomputer software or the like in accordance with a preset program based on the information. The switching valve 90 is appropriately controlled to switch in response to vibrations input under various conditions, such as the vehicle's running state, thereby controlling the pressure in the working air chamber 68 to obtain the desired vibration-proofing effect. In this embodiment, both the non-negative pressure type engine mount 12 (12') and the negative pressure type engine mount 13 are equipped with the switching control device 96, and the switching valve 90 is controlled by the switching control device 96 to switch.

[0050] Further, a release tube 98 is connected to the first port 92 of the switching valve 90, and the release tube 98 is open to the atmosphere. That is, the first port 92 in each of the engine mounts 12 (12'), 13 has a structure open to the atmosphere.

[0051] The above is the common structure of engine mounts 12 (12'), 13. Below, the differences between the non-negative pressure type engine mount 12 (12') shown in FIG. 2 and the negative pressure type engine mount 13 shown in FIG. 3 will be explained.

[0052] In the engine mount 12 (12') shown in FIG. 2, a blocking tube 100 is connected to the second port 94, and a cap 102 is attached to the end opening of the blocking tube 100 on the side opposite to the side connected to the second port 94. The blocking tube 100 and the cap 102 may be made of, for example, synthetic resin, and may have a certain degree of deformation rigidity. The fixing structure between the blocking tube 100 and the cap 102 is not limited and may be adhesive or welding, but for example, a male thread may be provided on the outer peripheral surface of the end opening of the blocking tube 100 on the side where the cap 102 is attached, and a female thread may be provided on the inner peripheral surface of the cap 102, and the cap 102 may be attached to the end opening of the blocking tube 100 by screwing these male threads and female threads to block the blocking tube 100. The blocking tube 100 also has a certain length.

[0053] In such a structure, when the switching valve 90 is switched by the switching control device 96 to connect the air pipe 88 (port section 72) and the second port 94, the internal spaces of the working air chamber 68, the air passage 70, the port section 72, and the air pipe 88 communicate with the internal space of the blocking tube 100, but by fixing a cap 102 to the end of the blocking tube 100, these internal spaces become sealed spaces, preventing or suppressing changes in volume, and the membrane 64 exerts a spring rigidity that is harder than when the working air chamber 68 is open to the atmosphere through the release tube 98. In such a case, the second port 94 is configured as a shutoff structure in which the cap 102 is attached to the blocking tube 100 connected to the second port 94 and is sealed by the cap 102.

[0054] 3, a connection tube 104 is connected to the second port 94, and a negative pressure source 106 is attached to the end of the connection tube 104 opposite to the end connected to the second port 94. The negative pressure source 106 can be, for example, the engine intake negative pressure.

[0055] In such a structure, when the switching valve 90 is switched by the switching control device 96 to connect the air pipeline 88 (port portion 72) and the second port 94, a suction force from the negative pressure source 106 is applied, causing the membrane 64 to be deformed by negative pressure suction toward the working air chamber 68, or the membrane 64 is further suctioned and overlapped with the bottom surface of the working air chamber 68, thereby restraining deformation and exerting a hard spring rigidity. In such a case, the second port 94 is connected to the negative pressure source 106 via the connection tube 104, and a suction structure is formed in which negative pressure is applied to the working air chamber 68.

[0056] When vibrations such as idling vibrations are input to the engine mounts 12 (12'), 13 as described above, pressure fluctuations of relatively large amplitude are induced in the primary fluid chamber 80. In such a case, in each engine mount 12 (12'), 13, the changeover valve 90 is switched by the changeover control device 96 to connect the air pipe 88 to the second port 94 (cap 102 or negative pressure source 106), thereby preventing or suppressing deformation of the secondary fluid chamber 84. This prevents pressure fluctuations in the primary fluid chamber 80 from escaping to the secondary fluid chamber 84, and the flow of fluid through the orifice passage 86 tuned to idling vibrations provides a good vibration damping effect.

[0057] In particular, in the non-negative pressure type engine mount 12 (12') shown in Fig. 2, the volume of the sealed space including the working air chamber 68 is determined by the internal spaces of the air passage 70, the port portion 72, the air duct 88, and the blocking tube 100 in addition to the working air chamber 68. That is, the volume of the sealed space can be adjusted by setting the blocking tube 100 to an appropriate length. And, since the air spring in the sealed space (internal space) acts as a supplementary or restrictive spring for the membrane 64, the hardness of the membrane 64 is determined by the volume of the sealed space.

[0058] The inventor actually prepared a number of blockage tubes 100 with different lengths, and fabricated a number of engine mounts 12, 12' with blockage tubes 100 of different lengths, and determined the spring characteristics (hardness of membrane 64) of the working air chamber 68 in each engine mount 12, 12', and the frequency characteristics of the vibration isolation characteristics (absolute spring constant) of the engine mounts 12, 12' based on the resonance action of the fluid flowing through the orifice passage 86 that changes accordingly. In this experiment, a standard blockage tube (blockage tube + 0 mm) and blockage tubes that were 50 mm (blockage tube + 50 mm), 100 mm (blockage tube + 100 mm), and 150 mm (blockage tube + 150 mm) longer than the standard blockage tube were prepared. The graph of the results is shown in FIG. 4. In the graph of FIG. 4, the vertical axis indicates the absolute spring constant of the engine mount 12, 12' (particularly the main rubber elastic body 18) on a linear scale (normal scale), and the higher the vertical axis, the higher the spring constant, and the lower the vertical axis, the lower the spring constant. As is clear from the circled portion in FIG. 4, the volume of the sealed space including the working air chamber 68 changes as the length of the blocking tube 100 changes, and the spring characteristic (hardness of the membrane 64) of the membrane 64 changes, and the resonance bottom frequency of the spring characteristic of the engine mount 12, 12' based on the flow action of the fluid flowing through the orifice passage 86 changes. Specifically, the longer the blocking tube 100, the lower the resonance bottom frequency becomes, and by appropriately setting the length dimension of the blocking tube 100, the resonance bottom frequency of the spring characteristic of the engine mount 12, 12' based on the flow action of the fluid flowing through the orifice passage 86 can be adjusted to a desired value. In the negative pressure type engine mount 13, a substantially constant suction restraint force acts on the membrane 64, and the length of the connecting tube 104 has almost no effect on the spring characteristics of the working air chamber 68, so the length of the connecting tube 104 is set to an appropriate length taking into consideration handling, etc. Therefore, it is possible to use, for example, the same tube as the blocking tube 100 used in the non-negative pressure type engine mount 12 (12') as the connecting tube 104.

[0059] On the other hand, when high-frequency, small-amplitude vibrations such as booming noise are input to the engine mounts 12 (12'), 13, the changeover valve 90 is switched to communicate the air duct 88 with the first port 92. Since the first port 92 is connected to the atmosphere via the open tube 98, the membrane 64 exhibits a relatively soft spring characteristic. As a result, the pressure fluctuations in the primary liquid chamber 80 are efficiently transmitted to the secondary liquid chamber 84 with the displacement of the movable plate 52 in the restrained installation area 48, and the pressure fluctuations in the primary liquid chamber 80 are reduced or eliminated by the fluid pressure absorption action based on the elastic deformation of the membrane 64, thereby exhibiting a good vibration-proofing effect. When high-frequency, small-amplitude vibrations are input, the orifice passage 86 tuned to a lower frequency range exhibits a significantly increased fluid flow resistance due to an anti-resonant action, and is substantially closed.

[0060] 1, by appropriately setting the length of the open tube 98, the volume of the internal space from the working air chamber 68 to the external space can be changed when the air pipeline 88 and the first port 92 are in communication with each other, and this also makes it possible to adjust the spring characteristics of the membrane 64, i.e., the working air chamber 68. As a result, in the vibration isolation mechanism based on the fluid flow through the through holes 50 between the primary liquid chamber 80 and the secondary liquid chamber 84, the resonance frequency can be tuned by varying the length of the open tube 98.

[0061] According to the vibration isolation system 10 of the present embodiment configured as described above, the engine mount 12 (12') shown in FIG. 2 can be used for a vehicle that does not have a negative pressure source 106 (for example, engine intake negative pressure), and the engine mount 13 shown in FIG. 3 can be used for a vehicle that has a negative pressure source 106 (for example, engine intake negative pressure), and these engine mounts 12, 12', 13 have many parts of a common structure. Specifically, in the engine mounts 12, 12', a blocking tube 100 and a cap 102 are connected to the second port 94, and in the engine mount 13, a connecting tube 104 and a negative pressure source 106 are connected to the second port 94. In short, by selecting whether the second port 94 has a blocking structure or a suction structure, and connecting either the cap 102 or the negative pressure source 106 to the tube (the blocking tube 100 or the connecting tube 104) connected to the second port 94, the non-negative pressure type engine mount 12 (12') and the negative pressure type engine mount 13 can be arbitrarily selected. As a result, by constructing an anti-vibration system 10 that combines an engine mount 12 (12') having a blocking structure in which a cap 102 is connected to the second port 94 via a blocking tube 100, and an engine mount 13 having a suction structure in which a negative pressure source 106 is connected to the second port 94 via a connection tube 104, it is possible to easily accommodate both vehicles that do not have a negative pressure source 106 (e.g., engine intake negative pressure) and vehicles that have a negative pressure source 106 (e.g., engine intake negative pressure) efficiently and at low cost.

[0062] In particular, the same switching control device 96 for switching the switching valve 90 can be used for both the non-negative pressure type engine mount 12 (12') and the negative pressure type engine mount 13, and there is no need to change the switching control device 96 when selecting between the non-negative pressure type engine mount 12 (12') and the negative pressure type engine mount 13. This makes it possible to standardize even the control system in each embodiment, and by simply changing whether to connect the cap 102 or the negative pressure source 106 without any major changes, it is possible to accommodate both vehicles that do not have the negative pressure source 106 and vehicles that have the negative pressure source 106.

[0063] Furthermore, in the non-negative pressure type engine mount 12, 12', the length dimension of the blocking tube 100 connected to the second port 94 is varied to adjust the spring characteristic in the working air chamber 68 when the air duct 88 (port portion 72) and the second port 94 are in communication with each other. This allows the resonance frequency to be easily tuned in an anti-vibration mechanism having, for example, an orifice passage 86, and by preparing a plurality of blocking tubes 100 with different lengths, a plurality of non-negative pressure type engine mounts 12, 12' with different spring characteristics in the working air chamber 68 can be adopted in various vehicles that do not have a negative pressure source 106 (for example, engine intake negative pressure). This allows the anti-vibration system 10 to be configured by a plurality of non-negative pressure type engine mounts 12, 12' with blocking tubes 100 with different lengths and a negative pressure type engine mount 13.

[0064] Similarly, by varying the length dimension of the open tube 98 connected to the first port 92, the spring characteristics in the working air chamber 68 when the air pipeline 88 (port portion 72) is in communication with the first port 92 can be adjusted. This makes it possible to easily tune the resonant frequency in the vibration isolation mechanism that relies on flow between the primary liquid chamber 80 and the secondary liquid chamber 84, in either the non-negative pressure type or the negative pressure type engine mount 12 (12'), 13, and to construct an anti-vibration system 10 having a plurality of engine mounts 12, 12', 13 whose resonant frequencies are set to desired values.

[0065] Although one embodiment of the present invention has been described in detail above, the present invention is in no way limited by the specific description of such an embodiment, and can be implemented in various forms with various changes, modifications, improvements, etc. based on the knowledge of those skilled in the art, and it goes without saying that all such embodiments are included within the scope of the present invention as long as they do not deviate from the spirit of the present invention.

[0066] For example, in the above embodiment, the primary liquid chamber 80 and the equilibrium chamber 82 are connected by the orifice passage 86, and the vibration-proof mechanism using the orifice passage 86 is tuned to mid-frequency, mid-amplitude vibrations corresponding to idling vibrations, and the vibration-proof mechanism using the primary liquid chamber 80 and the auxiliary liquid chamber 84 is tuned to high-frequency, low-amplitude vibrations corresponding to muffled noises while driving, but the present invention is not limited to this embodiment. That is, for example, the fluid-filled vibration-proof device may be applied to devices other than engine mounts, and may suppress vibrations other than the idling vibrations and muffled noises while driving exemplified in the above embodiment. In addition, the fluid-filled vibration-proof device is not limited to vibrations (frequency, amplitude, etc.) to be damped, and may have a vibration-proof effect against at least one of various vibrations such as low-frequency, high-amplitude vibrations, mid-frequency, mid-amplitude vibrations, and high-frequency, low-amplitude vibrations. The number of orifice passages is also not limited, and it is possible to provide two or more orifice passages depending on the vibrations to be damped. For example, in an engine mount having the basic structure as in the above embodiment, a second orifice passage that communicates the main liquid chamber with the auxiliary liquid chamber can be provided and the second orifice passage can be tuned to a different frequency range from the first orifice passage. The flow characteristics of the fluid through the second orifice passage, and therefore the vibration damping characteristics exhibited by the second orifice passage, can be appropriately adjusted by changing the spring hardness of the membrane that constitutes part of the wall of the auxiliary liquid chamber by switching the switching valve. It is desirable that the second orifice passage be tuned to a higher frequency range than the first orifice passage. In the fluid-filled vibration-damping device according to the present invention, the orifice passage that connects the main liquid chamber and the equilibrium chamber is not essential, including the equilibrium chamber, and for example, in a fluid-filled vibration-damping device that does not have an equilibrium chamber, low-frequency large-amplitude vibration (e.g., engine shake) and medium-frequency medium-amplitude vibration (e.g., idling vibration) may be suppressed by fluid flow through an orifice passage that connects the main liquid chamber and the auxiliary liquid chamber, and the vibration-damping characteristics may be changeable and set based on the switching of the switching valve. Also, the specific control mode of the switching operation of the switching valve can be set appropriately depending on the mode of vibration to be damped and the input conditions, and is not limited.

[0067] In addition, in the above embodiment, the occlusion tube 100 is closed by attaching the cap 102 to the end opening of the occlusion tube 100 on the side opposite to the side connected to the second port 94, but in one aspect of the present invention, the occlusion tube may be closed, for example, by welding or bonding the inner circumferential surface of the occlusion tube without providing a cap, or the end opening of the occlusion tube may be closed by filling it with a separate member. Note that the method of fixing the occlusion tube 100 and the cap 102 is not limited to the screwing of a male thread and a female thread exemplified in the above embodiment, and may be, for example, a press fit or a concave-convex fit.

[0068] Furthermore, in the above embodiment, engine mounts 12, 12' are exemplified as the fluid-filled type vibration damping device, and engine intake negative pressure is exemplified as the negative pressure source 106, but the present invention is not limited to this embodiment. The fluid-filled type vibration damping device may be a fluid-filled type vibration damping device for a vehicle other than an engine mount, such as a body mount or a differential mount, or may be a fluid-filled type vibration damping device for a vehicle other than a vehicle. Similarly, the negative pressure source employed in the fluid-filled type vibration damping device may be a negative pressure source provided in the vehicle other than the engine intake negative pressure, or may be a negative pressure source provided outside the vehicle.

[0069] The fluid-filled vibration-damping device of the present invention may, for example, be provided with an active air chamber and a switching valve communicating with the active air chamber, and the blocking tube and / or cap connected to the second port of the switching valve in the fluid-filled vibration-damping device may or may not constitute the fluid-filled vibration-damping device.

[0070] In the above embodiment, the vibration isolation system 10 includes a plurality of non-negative pressure type engine mounts 12, 12' having different lengths of the blockage tube 100 and a negative pressure type engine mount 13, but the present invention is not limited to this embodiment. In one embodiment of the vibration isolation system according to the present invention, the length of the blockage tube in the non-negative pressure type engine mount may be constant, and the vibration isolation system may be configured by combining such a non-negative pressure type engine mount and a negative pressure type engine mount. In another embodiment of the vibration isolation system according to the present invention, the negative pressure type engine mount is not essential, and the vibration isolation system may be configured by a plurality of non-negative pressure type engine mounts having blockage tubes with different lengths. [Explanation of symbols]

[0071] 10 Anti-vibration system 12,12',13 Engine mount (fluid-filled vibration isolation device) 14 First mounting member 16 Second mounting member 18 Main rubber elastic body 20 Fluid chamber 22 Bolt holes 24 Step 26 Large diameter cylinder 28 Small diameter cylinder part 29 Fitting protrusion 30 Large diameter recess 32 Sealing rubber layer 34 Partitioning material 36 Lid member 38 Partition member body 40 Central recess 42 Step surface 44 Circumferential groove 45 Connecting window 46 Annular protrusion 48 Constrained Placement Area 50 Through hole 52 Movable plate 54 Fixing member 56 Lower recess 58 Central protrusion 59 Fitting groove 60 Upper fitting groove 62 Lower fitting groove 64 Membrane 66 Fitting Ring 68 Working air chamber 70 Air passage 72 Port section 74 Diaphragm 76 Fixing bracket 78 Fitting protrusion 80 Main liquid chamber 82 Equilibrium chamber 84 Secondary liquid chamber 86 Orifice Passage 88 Air Pipe 90 Switching valve 92 First Port 94 Second Port 96 Switching control device 98 Open Tube 100 Blockage tube 102 Cap 104 Connecting tube 106 Negative pressure source

Claims

1. A vibration isolation system using a fluid-filled vibration isolation device in which a first mounting member and a second mounting member are connected by a main rubber elastic body and a fluid chamber is formed therein, In each of the fluid-filled vibration damping devices, a part of the wall of the fluid chamber is formed of a membrane, an operating air chamber is formed on the opposite side of the membrane from the fluid chamber, and a switching valve is provided which has a first port and a second port and selectively switches the ports to communicate with the operating air chamber, The first port is open to the atmosphere in any of the fluid-filled type vibration isolation devices, The second port is a vibration isolation system in which, in each of the fluid-filled vibration isolation devices, it is possible to select between an isolation structure in which a cap is attached and sealed by the cap, and a suction structure in which the second port is connected to a negative pressure source and negative pressure is applied to the working air chamber.

2. A switching control device is provided to control switching of the switching valve, 2. The vibration isolation system according to claim 1, wherein the switching control device switches the switching valve in the same manner in all of the fluid-filled type vibration isolation devices.

3. A vibration isolation system using a fluid-filled vibration isolation device in which a first mounting member and a second mounting member are connected by a main rubber elastic body and a fluid chamber is formed therein, In each of the fluid-filled vibration damping devices, a part of the wall of the fluid chamber is formed of a membrane, an operating air chamber is formed on the opposite side of the membrane from the fluid chamber, and a switching valve is provided which has a first port and a second port and selectively switches the ports to communicate with the operating air chamber, The first port is open to the atmosphere in each of the fluid-filled type vibration isolation devices, In any of the fluid-filled type vibration isolation devices, a blocking tube is attached to the second port, and an end opening of the blocking tube on the opposite side to the second port is blocked, In these fluid-filled vibration isolators, the length of the blocking tube is individually adjusted according to the required spring characteristics of the working air chamber.

4. The first port is provided with an open tube in each of the fluid-filled type vibration isolation devices, 4. The vibration isolation system according to claim 1, wherein in said fluid filled type vibration isolation devices, the length of said open tube is individually adjusted according to the required spring characteristics of said working air chamber.

Images