JP2009236282A - Fluid-sealed type vibration damping device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a fluid-sealed type vibration damping device of novel construction that requires no special actuator or control device, and that efficiently provides advanced vibration damping effect based on fluid resonance action against each of several types of vibration of different amplitude. <P>SOLUTION: A pressure receiving chamber 70 and an equilibrium chamber 72 communicate with each other through a main orifice passage 74, and an intermediate chamber 92 is formed separately from the pressure receiving chamber 70 and equilibrium chamber 72. A part of the wall portion of the intermediate chamber 92 is formed of an input-end moveable plate 76 transmitting pressure from the pressure receiving chamber 70 to the intermediate chamber 92 and having the restricted amount of displacement. The other part of the wall portion of the intermediate chamber 92 is formed of an output-end moveable plate 84 dispelling pressure fluctuations of the intermediate chamber 92 to the equilibrium chamber 72 and having the restricted amount of displacement so that an amount of capacity variability permitted in association with displacement is smaller than that of the input-end moveable plate 76. Further, the intermediate chamber 92 and equilibrium chamber 72 communicate with each other through a sub-orifice passage 96. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a fluid-filled vibration damping device that obtains a vibration-proofing effect based on the flow action of a fluid sealed inside.

  Conventionally, an anti-vibration device has been used to provide anti-vibration support for a vibration body such as an internal combustion engine with respect to a base member such as a vehicle body. For example, an automobile power unit is supported in an anti-vibration manner by an engine mount as a plurality of anti-vibration devices with respect to the vehicle body.

  By the way, an automobile engine mount is required to have a high level of vibration isolation performance in order to improve riding comfort. In order to meet such a demand, a fluid-filled vibration isolator using a fluid action such as a resonance action of an incompressible fluid has been proposed. As is well known, this fluid-filled vibration isolator has a structure in which an incompressible fluid is sealed by connecting a pressure receiving chamber to which vibration is input and a variable volume equilibrium chamber through an orifice passage. An anti-vibration effect is obtained based on the resonance action of an incompressible fluid that is caused to flow through the orifice passage when vibration is input.

  In addition, in an automobile engine mount, anti-vibration performance is required for a plurality of types of vibrations such as different frequencies and amplitudes depending on the engine speed, the vehicle running state, and the like. However, in the high-frequency range exceeding the tuning frequency range, the orifice passage causes a remarkable high dynamic spring due to the anti-resonance action, and the vibration-proof performance is greatly lowered.

  Therefore, conventionally, as described in Patent Document 1 (Japanese Patent Application Laid-Open No. 61-55429) and the like, a movable plate that can be finely displaced is disposed between the pressure receiving chamber and the equilibrium chamber. A hydraulic pressure absorption mechanism has been proposed in which the pressures of the pressure receiving chamber and the equilibrium chamber are exerted on one surface of each. However, such a hydraulic pressure absorption mechanism only reduces the pressure fluctuation in the pressure receiving chamber under the condition that the orifice passage is substantially closed due to anti-resonance, and thus still achieves the required high level of vibration isolation performance. There were cases where it was difficult to do.

  Specifically, even if a hydraulic pressure absorption mechanism is provided, there is only one orifice passage, so high vibration isolation effects by fluid resonance are provided for vibrations in different frequency ranges such as shake vibration and idling vibration. It was difficult to get. In addition, even if the vibration is in the same frequency range, the vibration is lower in the lower frequency range than the engine shake when the vehicle is running and the periodic idling vibration (generally idling secondary vibration) that accompanies the engine explosion during vehicle idling. When large-amplitude vibration and small-amplitude vibration are input in the same frequency range, such as irregular idling vibration with a stable bull feeling (hereinafter referred to as rough idling vibration), pressure is received when small-amplitude vibration is input. Since the pressure fluctuation in the chamber was released by the hydraulic pressure absorption mechanism, it was difficult to obtain an effective vibration isolation effect by the orifice passage.

  In order to cope with such a problem, for example, as described in Patent Document 2 (Japanese Patent Laid-Open No. 2005-172173) and the like, a plurality of orifice passages tuned different from each other are provided, and a valve is provided. Although an external control type fluid-filled engine mount that selectively blocks / communicates the plurality of orifice passages by a body has been proposed, an actuator for switching the valve body is required. Since a control device for generating a switching control signal is also required, there is a problem that the structure is complicated, the engine mount itself is increased in size and the cost is unavoidable, and is difficult to adopt.

  Further, as described in Patent Document 3 (Japanese Patent No. 2811448) and the like, a plurality of orifice passages tuned to different frequency ranges are provided in parallel between the pressure receiving chamber and the equilibrium chamber, There has also been proposed a passive amplitude-dependent switching type fluid-filled engine mount having a structure in which movable plates having different micro-displacement allowances are provided at the opening portion of the orifice passage toward the pressure receiving chamber.

  However, in the amplitude-dependent switching type fluid-filled engine mount of this conventional structure, it is necessary to set a difference in displacement allowance of only 1/10 mm or less for each movable plate. It was extremely difficult to stably obtain the performance as described above, and this was also not realistic. In addition, since each orifice passage is formed in parallel between the pressure receiving chamber and the equilibrium chamber, when vibration is input in the tuning frequency range of one orifice passage, all the orifice passages tuned to a higher frequency range are used. Since the pressure fluctuation of the pressure receiving chamber is absorbed due to the minute displacement of the other movable plate disposed in the chamber, there is a problem that the vibration isolation effect exhibited based on the resonance action of the fluid is reduced. there were.

JP 61-55429 A JP 2005-172173 A Japanese Patent No. 2811448

  Here, the present invention has been made in the background as described above, and the problem to be solved is that a plurality of types of different amplitudes can be used without requiring a special actuator or control device. It is an object of the present invention to provide a fluid-filled vibration isolator having a novel structure that can efficiently and highly obtain a vibration isolation effect based on the resonance action of a fluid.

  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.

  A fluid-filled vibration isolator according to the present invention includes: (a) a pressure receiving chamber in which an incompressible fluid is sealed, in which a part of a wall portion is formed of a main rubber elastic body and pressure fluctuation is caused when vibration is input; (B) a variable volume equilibrium chamber in which a part of the wall portion is formed of a flexible membrane and in which an incompressible fluid is enclosed; and (c) a main orifice passage that communicates the pressure receiving chamber and the equilibrium chamber with each other. (D) an intermediate chamber that is formed separately from the pressure receiving chamber and the equilibrium chamber and encloses an incompressible fluid; and (e) a pressure receiving surface disposed on the wall of the intermediate chamber opposite to the intermediate chamber. An input-side movable plate with a limited displacement amount, which transmits pressure from the pressure-receiving chamber to the intermediate chamber by causing pressure from the chamber to be displaced, thereby causing pressure fluctuation in the intermediate chamber; and (f) input. Apart from the side movable plate, it is arranged on the wall of the intermediate chamber to transmit the pressure fluctuation in the intermediate chamber to the equilibrium chamber. An output-side movable plate whose displacement is limited so that the volume variable amount allowed with the displacement is smaller than that of the input-side movable plate, and (g) the intermediate chamber and the equilibrium chamber are mutually connected. And a sub-orifice passage communicating with the sub-orifice passage.

  In the fluid-filled vibration isolator having the structure according to the present invention, an intermediate chamber is formed separately from the pressure receiving chamber and the equilibrium chamber, and the main orifice passage, the sub-orifice passage, the input side movable plate, and the output side movable plate. Are combined with each other, thereby realizing a switching function of the vibration-proof characteristic based on the amplitude utilizing the difference in the amplitude of the input vibration. In short, using multiple movable plates on the input side and output side to demonstrate the screening action by amplitude, it is possible to selectively function multiple orifice passages depending on the amplitude of input vibration. I was able to do it.

  More specifically, for example, assume input states of low-frequency large-amplitude vibration such as engine shake, medium-frequency medium-amplitude vibration such as idling vibration, and high-frequency small-amplitude vibration such as running-over sound. Here, the main orifice passage is tuned to a low frequency region such as an engine shake, and the sub-orifice passage is tuned to a medium frequency region such as idling vibration.

  In this case, the low-frequency large-amplitude vibration generates a pressure fluctuation in the pressure receiving chamber that exceeds the hydraulic pressure absorption by the input side movable plate, and the vibration-proofing effect based on the resonance action of the fluid flowing through the main orifice passage is low. Demonstrated against high-frequency vibration. During the input of medium frequency and medium amplitude vibration, the pressure fluctuation in the pressure receiving chamber caused by substantial clogging of the main orifice passage is transmitted to the intermediate chamber through the input side movable plate, and the hydraulic pressure is absorbed by the output side movable plate. Excessive pressure fluctuation is generated in the intermediate chamber, and the vibration isolation effect based on the resonance action of the fluid flowing through the sub-orifice passage is exhibited against the medium-frequency amplitude vibration. When high-frequency small-amplitude vibration is input, pressure fluctuation exerted from the pressure receiving chamber via the input-side movable plate to the intermediate chamber due to substantial clogging of the main orifice passage and the sub-orifice passage passes through the output-side movable plate. By letting it escape to the equilibrium chamber, vibration can be prevented by the low dynamic spring action. As described above, the vibrations of the low frequency large amplitude vibration such as engine shake, the medium frequency medium amplitude vibration such as idling vibration, and the high frequency small amplitude vibration such as running noise are switched based on the difference in amplitude of each vibration. Each of the anti-vibration characteristics effectively prevents vibration.

  Alternatively, assume each input state of low frequency large amplitude vibration such as engine shake, low frequency medium amplitude vibration such as rough idling vibration, and high frequency small amplitude vibration such as idling vibration. Here, both the main orifice passage and the sub-orifice passage are tuned to a low frequency range corresponding to engine shake or rough idling vibration. In the above-described case, the idling vibration is referred to as “medium frequency medium amplitude vibration” in contrast with the engine shake and the running noise, but here, the idling vibration is compared with the engine shake and the rough idling vibration. In this case, it is referred to as “high frequency small amplitude vibration”. In any case, the idling vibration itself is the same, but “Low / Medium / High” and “Small / Medium / Large” are relative evaluations and are expressed in comparison with others. There is no contradiction with respect to the change in expression as the conditions to be changed are different.

  In this case, the low-frequency large-amplitude vibration causes fluid flow through the main orifice passage due to large pressure fluctuations induced in the pressure receiving chamber, as in the above-mentioned assumption, and is prevented by high damping based on the resonance action of the fluid. The vibration effect is demonstrated. At the time of input of low frequency medium amplitude vibration, the pressure fluctuation induced in the pressure receiving chamber with input is small compared to the low frequency large amplitude vibration, so the pressure fluctuation of the pressure receiving chamber is changed to the intermediate chamber via the input side movable plate. Therefore, it is difficult to cause a sufficient pressure fluctuation in the pressure receiving chamber, so that it is difficult to secure a fluid flow amount through the main orifice passage, and the vibration isolation effect by the main orifice passage is reduced. However, the fluid flow through the sub-orifice passage is generated based on the pressure fluctuation induced in the intermediate chamber, and the vibration isolation effect based on the fluid flow through the sub-orifice passage is the anti-vibration effect based on the fluid flow through the main orifice passage. It is demonstrated in combination with the vibration effect. As a result, a highly damped vibration-proofing effect based on the resonance action of the fluid is effectively exhibited even for low-frequency medium amplitude vibrations such as rough idling vibrations. Also, for high-frequency small-amplitude vibration such as idling vibration, the input-side movable plate from the pressure receiving chamber is accompanied by substantial clogging of the main orifice passage and the sub-orifice passage, as in the case of the booming noise in the above assumption. The pressure fluctuation exerted on the intermediate chamber via the squeezing can escape to the equilibrium chamber via the output side movable plate, and can be prevented from vibration by the low dynamic spring action.

  As described above, in the fluid filled type vibration isolator constructed according to the present invention, the valve body for opening and closing the orifice passage, the actuator for opening and closing the orifice passage, and the control device for controlling the operation of the actuator are complicated and expensive. Without requiring a special mechanism, the vibration isolation effect based on the flow action of the sealed fluid can be effectively exhibited for each of a plurality of types of vibrations having different amplitudes.

  In the present invention, the input side movable plate and the output side movable plate may be any material that can transmit pressure between the pressure receiving chamber, the intermediate chamber, and the equilibrium chamber based on the elastic deformation and displacement. Specifically, the input side movable plate and the output side movable plate may be formed of a plate-like rubber elastic body, or may be formed of a hard plate-like body that does not substantially elastically deform. Alternatively, it may be a composite structure in which a rubber elastic body is fixed to a hard plate-like body. More specifically, a rubber elastic body is adhered and formed on the outer peripheral edge of a hard plate-like body, and the structure is such that the plate-like body is elastically supported to be displaceable via this rubber elastic body. It is also possible to configure a side movable plate or an output side movable plate.

  Further, in the present invention, the structure in which the volume variable amount allowed with the displacement of the output side movable plate is made smaller than the volume variable amount allowed with the displacement of the input side movable plate is specifically limited. It is not something. When a suitable structure is illustrated, for example, when the movable plates are displaced in the plate thickness direction, a structure that restricts the displacement amount by contacting is adopted, and the allowable displacement amount of the movable plate in the plate thickness direction is adjusted. Thus, it is possible to realize a structure in which the volume variable amount allowed with the displacement of the output side movable plate is smaller than the volume variable amount allowed with the displacement of the input side movable plate. Alternatively, the output side movable plate can also be displaced or deformed based on the pressure action so that the area (effective area) of pressure transmission is smaller than the effective area of the input side movable plate. It is possible to realize a structure in which the volume variable amount allowed with the displacement is smaller than the volume variable amount allowed with the displacement of the input side movable plate. It is also possible to employ the former relative adjustment structure of the displacement amount of the movable plate and the latter relative adjustment structure of the effective area in combination with each other.

  In particular, when varying the variable amount of volume between the movable plates, the latter effective area relative adjustment structure is adopted, and the effective area of the output movable plate is set smaller than the effective area of the input movable plate. However, it is easier to design, manufacture, and confirm than to set the allowable displacement amount between the movable plates differently, and it is possible to obtain the desired vibration isolation characteristics with higher accuracy.

  Furthermore, in the present invention, the main orifice passage and the sub-orifice passage may be tuned to different frequency ranges as in the former in the above-mentioned assumed case, or the same frequency range as in the latter in the aforementioned assumed case. It may be tuned to. By tuning to different frequency ranges, it is possible to obtain an anti-vibration effect based on the fluid action of the fluid that can flow through each orifice passage with respect to vibrations in more different frequency ranges. Further, by tuning to the same frequency range, it is possible to obtain an anti-vibration effect based on the fluid action of the fluid that can flow through each orifice passage, even for a plurality of types of vibrations with different amplitudes.

  In the present invention, the number of intermediate chambers is not limited, and there may be one or more intermediate chambers.

  In particular, when one intermediate chamber is provided in the present invention, the input side movable plate is disposed between the pressure receiving chamber and the intermediate chamber, and the pressure of the pressure receiving chamber is exerted on one surface of the input side movable plate. At the same time, the pressure of the intermediate chamber is applied to the other surface, and the input side movable plate is displaced based on the pressure difference between the pressure receiving chamber and the equilibrium chamber, whereby the pressure fluctuation in the pressure receiving chamber is transmitted to the intermediate chamber. On the other hand, an output-side movable plate is disposed between the intermediate chamber and the equilibrium chamber, and the output-side movable plate is displaced based on the pressure difference between the intermediate chamber and the equilibrium chamber, so that the pressure fluctuation in the intermediate chamber is transferred to the equilibrium chamber. A configuration that allows escape is preferably employed.

  According to such an embodiment, the pressure receiving chamber, the intermediate chamber, and the equilibrium chamber can be formed with a minimum number of formations, and can be arranged and formed in a structure adjacent to each other across the input side movable plate and the output side movable plate, A compact size can be realized.

  In the present invention, when a plurality of intermediate chambers are provided, the plurality of intermediate chambers are arranged in series between the pressure receiving chamber and the equilibrium chamber, and in the two intermediate chambers arranged in series with each other, A configuration in which the output side movable plate in one intermediate chamber positioned on the pressure receiving chamber side is made to function as the input side movable plate in the other intermediate chamber positioned on the equilibrium chamber side is suitably employed.

  According to such an embodiment, it is possible to form a plurality of sub-orifice passages that respectively connect the plurality of intermediate chambers to the equilibrium chamber. And by appropriately setting the tuning of these sub-orifice passages, it is possible to obtain effective vibration isolation characteristics corresponding to a wider range against vibrations of a wider frequency range or vibrations of different amplitudes. It becomes possible. In addition, since the plurality of intermediate chambers are arranged in series with the movable plate interposed therebetween, it is possible to suppress an increase in the size of the entire vibration isolator.

  In any case where one or a plurality of intermediate chambers are provided as described above, the input side movable plate and the output side movable plate are preferably set to have the same displacement direction as the plate thickness direction. More preferably, the displacement direction is set to be the same as the input direction of the main vibration to be shaken. Thereby, the further improvement of the efficiency of the pressure transmission by a movable plate can be achieved.

  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.

  FIG. 1 shows an automotive engine mount 10 as an embodiment of a fluid filled type vibration damping device according to the present invention. The engine mount 10 has a structure in which a first mounting bracket 12 as a first mounting member and a second mounting bracket 14 as a second mounting member are connected by a main rubber elastic body 16. The first mounting bracket 12 is attached to a power unit (not shown), and the second mounting bracket 14 is attached to a vehicle body (not shown) via the cylindrical bracket 18 so that the power unit is vibration-proof against the vehicle body. It is supported. In the following description, the vertical direction means the vertical direction in FIG. 1 in principle.

  More specifically, the first mounting member 12 is made of a metal material such as iron or aluminum alloy, and has an inverted truncated cone shape as a whole. A mounting bolt 20 is integrally formed on the large-diameter side end face of the first mounting bracket 12 so as to protrude upward in the axial direction.

  On the other hand, the second mounting bracket 14 is formed of a metal material such as iron or aluminum alloy like the first mounting bracket 12 and has a large-diameter cylindrical shape as a whole. Further, the second mounting bracket 14 is formed with a groove-like constricted portion 22 that is recessed inward in the radial direction and continuously extending in the circumferential direction at the upper end portion in the axial direction.

  The second mounting member 14 having such a structure is separated from the axially upper opening side, and the first mounting member 12 is disposed on substantially the same central axis. A main rubber elastic body 16 is disposed between the first mounting bracket 12 and the second mounting bracket 14, and the first mounting bracket 12 and the second mounting bracket are arranged by the main rubber elastic body 16. 14 are elastically connected.

  The main rubber elastic body 16 has a truncated cone shape as a whole, and a large-diameter recess 24 having an inverted mortar shape that opens downward is formed on the end surface on the large-diameter side. Further, the small diameter side end of the main rubber elastic body 16 is embedded and vulcanized and bonded so that the first mounting bracket 12 is inserted, and the large diameter side end of the main rubber elastic body 16 is also inserted. The opening on the upper side in the axial direction of the second mounting member 14 is overlapped and vulcanized and bonded to the outer peripheral surface. As is clear from this, in this embodiment, the main rubber elastic body 16 is an integrally vulcanized molded product including the first mounting bracket 12 and the second mounting bracket 14. In the present embodiment, the entire constricted portion 22 is positioned on the outer peripheral surface of the main rubber elastic body 16, and the rubber elastic body integrally formed with the main rubber elastic body 16 is the outer peripheral side of the constricted portion 22. Filled and fixed to.

  Further, the opening of the second mounting bracket 14 is vulcanized and bonded to the outer peripheral surface of the main rubber elastic body 16 in this way, so that the opening on the upper side in the axial direction of the second mounting metal 14 is the main rubber elastic body. 16 is covered fluid-tightly.

  Furthermore, a seal rubber layer 26 is formed on the inner peripheral surface of the second mounting bracket 14. The seal rubber layer 26 is formed integrally with the main rubber elastic body 16 and has a thin cylindrical shape extending downward from the peripheral edge of the opening of the large diameter recess 24. In particular, in the present embodiment, the seal rubber layer 26 is formed so as to adhere to a predetermined length from the lower side of the constricted portion 22 in the second mounting bracket 14.

  Moreover, the diaphragm 28 as a flexible film is assembled | attached to the 2nd attachment metal fitting 14 so that the opening part below the axial direction may be covered. The diaphragm 28 is formed of a thin rubber film, and has a substantially disk shape with rippled slack.

  Further, a cylindrical fixing bracket 30 is vulcanized and bonded to the outer peripheral edge of the diaphragm 28. Particularly in the present embodiment, the outer peripheral edge of the diaphragm 28 extends from the upper end side of the fixture 30 to the outer peripheral surface of the fixture 30. Thereby, the seal rubber layer 32 integrally formed with the diaphragm 28 is attached to the upper end surface and the outer peripheral surface of the fixture 30.

  In the diaphragm 28 having such a structure, the second mounting bracket 14 is subjected to diameter reduction processing such as an eight-way drawing in a state where the fixing bracket 30 is fitted in the lower end portion of the second mounting bracket 14. Thus, the second mounting member 14 is fixed to the lower end portion in the axial direction.

  When the diaphragm 28 is assembled to the second mounting bracket 14 in this manner, the opening on the upper side in the axial direction of the second mounting bracket 14 is fluid-tightly closed by the main rubber elastic body 16 and the second mounting bracket 14 is attached. The opening on the lower side in the axial direction of the metal fitting 14 is covered with a diaphragm 28 in a fluid-tight manner. Thereby, on the inner peripheral side of the second mounting bracket 14, a fluid chamber 34 sealed from the outside is formed between the main rubber elastic body 16 and the diaphragm 28 in the axial direction. The fluid chamber 34 is filled with an incompressible fluid such as water, alkylene glycol, polyalkylene glycol, or silicone oil. The incompressible fluid is sealed in the fluid chamber 34 by using a diaphragm 28 for the integrally vulcanized molded product of the main rubber elastic body 16 having the first mounting bracket 12 and the second mounting bracket 14 or a partition member to be described later. For example, the assembly of 36 may be advantageously performed in an incompressible fluid.

  A partition member 36 is accommodated in the fluid chamber 34. The partition member 36 has a circular block shape as a whole, and includes a partition member main body 38, an upper partition plate 40 that is superimposed on the upper end surface of the partition member main body 38, and a lower surface that is superimposed on the lower end surface of the partition member main body 38. The side partition plate 42 is used.

  The partition member main body 38 is formed of a hard synthetic resin material and has a circular block shape as a whole. A circumferential groove 44 that opens to the outer circumferential surface is formed in the outer circumferential portion of the partition member main body 38 so as to extend in the circumferential direction with a length of less than two rounds. In the present embodiment, one end in the circumferential direction of the upper circumferential groove 46 that opens to the outer peripheral surface at the upper end side in the axial direction and extends a little less than one round in the circumferential direction and the outer peripheral surface that opens to the outer peripheral surface at the lower end side in the axial direction. The other circumferential end of the lower circumferential groove 48 extending slightly less than one round in the direction is communicated with each other through the connection hole 50, thereby opening the outer peripheral portion of the partition member body 38 to the outer peripheral surface in the circumferential direction. A circumferential groove 44 extending in a length of a little less than two rounds is formed.

  Further, a central hole 52 penetrating with a circular cross section in the axial direction is formed in the central portion in the radial direction of the partition member main body 38. Therefore, in the present embodiment, annular step surfaces 54 and 56 are formed in the vicinity of both axial ends of the inner peripheral surface of the center hole 52, respectively. As a result, the center hole 52 has an axially intermediate portion as a small diameter portion 58 and axially opposite end portions as large diameter portions 60 and 62. In this embodiment, the upper large-diameter portion 60 formed on the upper side in the axial direction and the lower large-diameter portion 62 formed on the lower side in the axial direction have the same axial dimension and radial dimension. .

  In the present embodiment, the inner peripheral surface of the small-diameter portion 58 in the center hole 52 is formed with a tapered surface that gradually increases in diameter as it goes outward in the axial direction at each of both end portions in the axial direction. As a result, the small-diameter portion 58 of the center hole 52 has the smallest radial dimension at the axially intermediate portion.

  Furthermore, the partition member main body 38 includes an inner peripheral surface of an axially intermediate portion of the small diameter portion 58 in the center hole 52 (a portion in which the radial dimension is the smallest in the center hole 52) and a lower end surface of the partition member main body 38. A communication passage 64 is formed at a position excluding the circumferential groove 44 and the center hole 52. The passage length of the communication passage 64 is sufficiently shorter than the length of the circumferential groove 44 in the groove direction.

  Further, the upper partition plate 40 is formed of a hard synthetic resin material and has an annular plate shape with a central hole 66. Therefore, in this embodiment, the outer diameter dimension of the upper partition plate 40 is smaller than the outer diameter dimension of the partition member main body 38, but a large diameter recess formed in the large diameter side end surface of the main rubber elastic body 16. It is made larger than the inner diameter dimension of 24 open ends. In the present embodiment, the inner diameter dimension of the upper partition plate 40 is smaller than the inner diameter dimension of the upper large diameter portion 60 of the center hole 52 provided in the partition member main body 38.

  Further, the lower partition plate 42 is formed of a hard synthetic resin material and has an annular plate shape with a central hole 68. Therefore, in this embodiment, the outer diameter dimension of the lower partition plate 42 is sufficiently smaller than the outer diameter dimension of the partition member main body 38. On the other hand, the inner diameter dimension of the lower partition plate 42 is made smaller than the inner diameter dimension of the lower large diameter portion 62 of the center hole 52 provided in the partition member main body 38.

  The partition member body 38, the upper partition plate 40, and the lower partition plate 42 configured as described above are overlapped with the upper end surface of the partition member body 38 on the same central axis as the partition member body 38. At the same time, the lower partition plate 42 is superimposed on the lower end surface of the partition member main body 38 on the same central axis as the partition member main body 38, and is fixed by screws or ultrasonic welding (not shown) to form the partition member 36. is doing. Further, by forming the partition member 36 in this way, the upper large-diameter portion 60 and the lower large-diameter portion 62 have the same dimensions and open radially inwardly to the entire circumference in the circumferential direction. The groove is an annular groove extending continuously and circularly.

  The partition member 36 having such a structure is disposed between the axially opposed surfaces of the main rubber elastic body 16 and the diaphragm 28 on the inner peripheral side of the second mounting bracket 14.

  That is, before the diaphragm 28 is assembled to the second mounting bracket 14, the partition member 36 is inserted from the lower opening in the axial direction of the second mounting bracket 14, and the inner periphery of the second mounting bracket 14 is inserted. Placed on the side. At that time, the outer peripheral edge of the upper partition plate 40 is sandwiched between the upper peripheral edge of the partition member main body 38 and the open end surface of the large-diameter recess 24 formed in the main rubber elastic body 16.

  In this state, the diaphragm 28 is inserted from below in the axial direction and overlapped with the partition member 36 from below. At that time, the fixing bracket 30 of the diaphragm 28 is brought into contact with the outer peripheral edge portion of the lower end surface of the partition member main body 38 through the seal rubber layer 32.

  Then, with the partition member 36 and the diaphragm 28 inserted, the second mounting bracket 14 is subjected to a diameter reduction process such as an eight-way stop so that the second mounting bracket 14 is separated from the partition member 36. The diaphragm 28 is fitted and fixed. At that time, the outer peripheral edge of the upper partition plate 40 is held between the upper end outer peripheral edge of the partition member main body 38 and the opening end surface of the large-diameter recess 24 formed in the main rubber elastic body 16. Thus, the partition member main body 38 is fixed.

  In the present embodiment, the outer peripheral surface of the partition member 36 is overlapped with the inner peripheral surface of the second mounting bracket 14 via the seal rubber layer 26, and the space between the second mounting bracket 14 and the partition member 36 is between. It is fluid tightly sealed. In the present embodiment, when the diameter of the second mounting member 14 is reduced, the amount of diameter reduction of the portion where the diaphragm 28 is inserted is larger than the portion where the partition member 36 is inserted. Has been. Thereby, fixing of the partition member 36 and the diaphragm 28 is effectively realized while preventing the partition member 36 made of synthetic resin from being damaged. Furthermore, when the diameter of the second mounting bracket 14 is reduced, the lower end of the second mounting bracket 14 is processed into a tapered cylindrical shape that decreases in diameter as it goes downward, thereby preventing the diaphragm 28 from coming out downward. ing.

  In such an assembled state of the partition member 36, the fluid chamber 34 is divided into two parts up and down with the partition member 36 interposed therebetween. As a result, on one side in the axial direction across the partition member 36, a part of the wall portion is constituted by the main rubber elastic body 16, and a pressure receiving chamber 70 is formed in which internal pressure fluctuations are generated when vibration is input. In addition, on the other side in the axial direction with the partition member 36 interposed therebetween, a part of the wall portion is constituted by the diaphragm 28, and an equilibrium chamber 72 in which volume change is easily allowed is formed.

  In addition, the outer peripheral side opening of the circumferential groove 44 formed in the partition member 36 is covered with the second mounting bracket 14 via the seal rubber layer 26, and the circumferential groove 44 is used to have a predetermined length in the circumferential direction. An extending tunnel-like flow path is formed. One end of the tunnel-shaped flow path is connected to the pressure receiving chamber 70 through the communication hole 69, and the other end is connected to the equilibrium chamber 72 through the communication hole 71. Thus, a first orifice passage 74 is formed as a main orifice passage that extends in the circumferential direction by a predetermined length using the circumferential groove 44 and communicates the pressure receiving chamber 70 and the equilibrium chamber 72 with each other. . In the present embodiment, the resonance frequency (tuning frequency) of the fluid that flows through the first orifice passage 74 is tuned to a low frequency range of about 10 Hz corresponding to the engine shake or rough idling vibration of the automobile.

  Further, an upper movable rubber plate 76 as an input side movable plate is disposed in the upper large diameter portion 60 of the center hole 52 formed in the partition member main body 38. The upper movable rubber plate 76 is formed of a conventionally known rubber material and has a thick disk shape as a whole.

  Therefore, in the present embodiment, rib protrusions 78 projecting on both sides in the thickness direction are formed over the entire circumference at the outer peripheral edge of the upper movable rubber plate 76. In the present embodiment, the outer peripheral edge of the upper movable rubber plate 76 protrudes with a protrusion height larger than the protrusion height of the rib protrusion 78 and protrudes radially inward from the inner peripheral surface of the rib protrusion 78. A plurality of supporting protrusions 80 are formed at appropriate intervals in the circumferential direction.

  In the present embodiment, the upper movable rubber plate 76 is embedded with a reinforcing bracket 82 that is formed of a metal material such as iron or aluminum alloy and has an annular plate shape. Note that a reinforcing plate made of another material such as a synthetic resin may be employed in place of the reinforcing bracket 82. What is necessary is just to be harder than the rubber elastic body which forms the rib protrusion 78 grade | etc.,.

  The upper movable rubber plate 76 having such a structure includes an upper step surface 54 in which a plurality of support protrusions 80 provided on the outer peripheral edge portion are formed on the inner peripheral surface of the center hole 52 and an inner side of the upper partition plate 40. In a state where the pressure is held between the peripheral portions, the upper large-diameter portion 60 is accommodated and disposed in the upper large-diameter portion 60 so as to spread in the direction perpendicular to the axis on the same central axis as the upper large-diameter portion 60. Accordingly, the upper surface of the upper movable rubber plate 76 is exposed to the pressure receiving chamber 70 through the central hole 66 of the upper partition plate 40, and the lower surface of the upper movable rubber plate 76 is located above the small diameter portion 58 in the central hole 52. It is located above the opening and extends to cover the upper opening.

  Therefore, in the state where the upper movable rubber plate 76 is accommodated in the upper large-diameter portion 60 as described above, the upper movable surface between the upper end surface of the rib protrusion 78 of the upper movable rubber plate 76 and the upper partition plate 40 or the upper movable plate. There are gaps between the lower end surface of the rib protrusion 78 of the rubber plate 76 and the upper step surface 54, and between the outer peripheral surface of the upper movable rubber plate 76 and the inner peripheral surface of the upper large diameter portion 60, respectively. Is formed. As a result, the upper movable rubber plate 76 is accommodated and disposed in the upper large-diameter portion 60 in a state where displacement in the thickness direction is allowed as a whole in a portion excluding a portion where the plurality of support protrusions 80 are formed. Yes.

  In short, the upper movable rubber plate 76 of the present embodiment allows displacement in the thickness direction of the central portion to which the reinforcing metal fitting 82 is fixed by elastic deformation at the outer peripheral edge portion where the plurality of support protrusions 80 are formed. It is like that. Moreover, the allowable displacement in the thickness direction of the central portion is limited in a buffering manner by the spring stiffness at the outer peripheral edge of the upper movable rubber plate 76. Further, when a larger pressure is applied to the upper movable rubber plate 76, the outer peripheral portion of the upper movable rubber plate 76 forms the upper large-diameter portion 60 on both side walls in the width direction of the annular groove. By contacting the inner surface, the amount of displacement of the upper movable rubber plate 76 is mechanically limited to prevent damage. The gap as described above is not essential in the present invention. For example, the outer peripheral edge of the upper movable rubber plate 76 is formed on the entire inner periphery of the upper large-diameter portion 60 by an annular elastic protrusion. It may be arranged in contact with.

  In addition, a lower movable rubber plate 84 as an output side movable plate is disposed in the lower large diameter portion 62 of the center hole 52 formed in the partition member main body 38. In the present embodiment, the lower movable rubber plate 84 is formed in substantially the same shape and size as the upper movable rubber plate 76 described above. However, in this embodiment, the forming material of the lower movable rubber plate 84 is different from the forming material of the upper movable rubber plate 76. Thereby, the elasticity of the lower movable rubber plate 84 and the ease of displacement of the upper movable rubber plate 76 in the thickness direction are different. Specifically, the lower movable rubber plate 84 has a larger rubber hardness than the upper movable rubber plate 76 to increase the spring rigidity, and the amount of displacement in the plate thickness direction under the same pressure action is lower. The side movable rubber plate 84 is restricted to be smaller than the upper movable rubber plate 76.

  In the figure, reference numeral 86 attached to the lower movable rubber plate 84 is a rib protrusion corresponding to the reference numeral 78 of the upper movable rubber plate 76, and reference numeral 88 corresponds to the reference numeral 80 of the upper movable rubber plate 76. The reference numeral 90 is a reinforcing metal fitting corresponding to the reference numeral 82 of the upper movable rubber plate 76.

  The lower movable rubber plate 84 having such a structure has a lower step surface 56 and a lower partition plate in which a plurality of support protrusions 88 provided on the outer peripheral edge portion are formed on the inner peripheral surface of the center hole 52. In a state where the pressure is held between the inner peripheral edge portions of 42, the lower large diameter portion 62 is accommodated and disposed in the lower large diameter portion 62 so as to spread in the direction perpendicular to the axis on the same central axis as the lower large diameter portion 62. It has become. As a result, the upper surface of the lower movable rubber plate 84 is positioned below the lower opening of the small diameter portion 58 in the center hole 52 and extends to cover the lower opening, and the lower movable rubber plate 84. Is exposed to the equilibrium chamber 72 through the central hole 68 of the lower partition plate 42.

  In this state, when the lower movable rubber plate 84 is accommodated in the lower large-diameter portion 62 as described above, it is between the upper end surface of the rib protrusion 86 of the lower movable rubber plate 84 and the lower step surface 56. Or between the lower end surface of the rib protrusion 86 of the lower movable rubber plate 84 and the lower partition plate 42, and between the outer peripheral surface of the lower movable rubber plate 84 and the inner peripheral surface of the lower large-diameter portion 62. In the meantime, gaps are formed, but these gaps are not essential in the present invention, and an arrangement similar to the case of the upper movable rubber plate 76 can be adopted.

  Thus, the upper movable rubber plate 76 and the lower movable rubber plate 84 are opposed to each other in the center hole 52 of the partition member main body 38 in which the upper movable rubber plate 76 and the lower movable rubber plate 84 are disposed as described above. An intermediate chamber 92 in which an incompressible fluid is sealed is formed between the surfaces.

  The pressure of the pressure receiving chamber 70 is applied to the upper surface of the upper movable rubber plate 76 through the central hole 66 of the upper partition plate 40, while the intermediate chamber 92 is applied to the lower surface of the upper movable rubber plate 76. The pressure is to be exerted. As a result, the upper movable rubber plate 76 is elastically displaced in the thickness direction based on the pressure difference between the pressure receiving chamber 70 and the intermediate chamber 92, so that the pressure fluctuation in the pressure receiving chamber 70 is transmitted to the intermediate chamber 92. It is like that.

  Further, the pressure of the intermediate chamber 92 is applied to the upper surface of the lower movable rubber plate 84, while the lower surface of the lower movable rubber plate 84 is passed through the central hole 68 of the lower partition plate 42. The pressure of the equilibrium chamber 72 is exerted. As a result, the lower movable rubber plate 84 is elastically displaced in the thickness direction based on the pressure difference between the intermediate chamber 92 and the equilibrium chamber 72, so that the pressure fluctuation in the intermediate chamber 92 is released to the equilibrium chamber 72. It is like that.

  Therefore, in the present embodiment, the displacement rigidity of the lower movable rubber plate 84 is larger than that of the upper movable rubber plate 76, and the shapes and sizes of the lower movable rubber plate 84 and the upper movable rubber plate 76 are the same. Since they are substantially the same, the amount of elastic deformation of the lower movable rubber plate 84 is made smaller than the amount of elastic displacement of the upper movable rubber plate 76 when the same pressure is applied. In short, the volume change amount of the intermediate chamber 92 allowed based on the displacement of the lower movable rubber plate 84 is smaller than the volume change amount of the intermediate chamber 92 allowed based on the displacement of the upper movable rubber plate 76. Has been.

  Accordingly, when vibration is input between the first mounting bracket 12 and the second mounting bracket 14 in the mount axial direction (the axial direction indicated by the one-dot chain line in FIG. 1), the pressure variation in the pressure receiving chamber 70. As a result, the upper movable rubber plate 76 is displaced in the thickness direction by the pressure fluctuation, and the pressure fluctuation is transmitted to the intermediate chamber 92. The pressure fluctuation in the intermediate chamber 92 tends to cause the displacement of the lower movable rubber plate 84, but the displacement rigidity of the lower movable rubber plate 84 is larger than the displacement rigidity of the upper movable rubber plate 76. As a result of suppressing the escape of the pressure of the intermediate chamber 92 to the equilibrium chamber 72 due to the displacement of the side movable rubber plate 84, pressure fluctuations are effectively generated in the intermediate chamber 92.

  The communication passage 64 formed in the partition member main body 38 has one end connected to the intermediate chamber 92 and the other end connected to the equilibrium chamber 72 through the communication hole 94. Accordingly, a second orifice passage 96 is formed as a sub-orifice passage that communicates the intermediate chamber 92 and the equilibrium chamber 72 with each other using the communication passage 64. In the present embodiment, the resonance frequency (tuning frequency) of the fluid that flows through the second orifice passage 96 is tuned to a medium frequency range of 15 to 30 Hz corresponding to idling vibration of the automobile.

  Incidentally, a schematic configuration of the engine mount 10 having such a structure is modeled as shown in FIG. As shown in this figure, the volume change allowed by the displacement of the upper movable rubber plate 76 is made larger than the volume change allowed by the displacement of the lower movable rubber plate 84. In the above-described embodiment, the lower movable rubber plate is based on the difference between the spring rigidity of the rubber elastic body forming the upper movable rubber plate 76 and the spring rigidity of the rubber elastic body forming the lower movable rubber plate 84. 84 has been set to be smaller than the displacement allowance in the plate thickness direction of the upper movable rubber plate 76, but in the model diagram of FIG. The difference in relative allowable volume change between the upper movable rubber plate 76 and the lower movable rubber plate 84 is represented by the size of the gap, not the rigidity.

  The engine mount 10 having the above-described structure is attached to the power unit by the first mounting bracket 12 being screwed and fixed to the mounting member on the power unit side by the mounting bolt 20. On the other hand, a fixing bolt (not shown) is inserted into the bolt insertion hole 100 provided in the mounting leg portion 98 of the cylindrical bracket 18 where the second mounting bracket 14 is fitted and fixed to the second mounting bracket 14. )) By being screwed and fixed to the vehicle body. Thereby, the engine mount 10 is interposed between the power unit of the automobile which is one member to be vibration-proof connected and the body of the automobile which is the other member to be vibration-proof connected, and the power unit is attached to the vehicle body. It is designed to support vibration isolation.

  Note that, when the engine mount 10 is mounted on a vehicle, the shared support load of the power unit is exerted between the first mounting bracket 12 and the second mounting bracket 14 in a substantially axial direction, so that the main body The rubber elastic body 16 is elastically deformed by a predetermined amount, and the first mounting bracket 12 and the second mounting bracket 14 are brought close to each other by a predetermined amount in the axial direction.

  When the engine mount 10 having the above-described structure is mounted on an automobile and low-frequency large-amplitude vibration such as an engine shake that becomes a problem during traveling is input, a large amplitude pressure fluctuation occurs in the pressure receiving chamber 70. Squeezed. At that time, a displacement based on the elastic deformation of the upper movable rubber plate 76 is generated, but the displacement of the upper movable rubber plate 76 within a limited range cannot effectively absorb the pressure fluctuation of the pressure receiving chamber 70. The elasticity of the upper movable rubber plate 76 is set.

  Accordingly, when the low-frequency large-amplitude vibration is input, the upper movable rubber plate 76 and the intermediate chamber 92 are hardly functioning, and accordingly, the fluid flow through the second orifice passage 96 is also almost generated. No state. Incidentally, FIG. 3 shows a functional configuration of the engine mount 10 in this state as a model.

  That is, in such a state, the pressure receiving chamber 70 into which vibration is input and the variable volume balance chamber 72 are connected through the first orifice passage 74 tuned to a low frequency region. Therefore, the amount of fluid flow through the first orifice passage 74 can be effectively ensured by the relative pressure fluctuation generated between the pressure receiving chamber 70 and the equilibrium chamber 72 at the time of vibration input. An effective anti-vibration effect is exhibited against low-frequency large-amplitude vibrations such as engine shake, based on the resonance action of the fluid flowing through the passage 74.

  In addition, when inputting low-frequency medium-amplitude vibration such as rough idling vibration, which is a problem when the vehicle is stopped, it is smaller than the amplitude of pressure fluctuation that is generated when low-frequency large-amplitude vibration such as engine shake is input, but it is somewhat large. A pressure fluctuation with an amplitude is generated in the pressure receiving chamber 70. At this time, the displacement of the upper movable rubber plate 76 within a limited range is set so that the pressure absorbing function of the pressure receiving chamber 70 is hardly exhibited. As a result, the first orifice is provided in the same manner as the engine shake. The vibration isolation effect (high attenuation effect) by the passage 74 can be effectively exhibited.

  On the other hand, pressure fluctuations induced in the pressure receiving chamber 70 at the time of inputting medium-frequency small-amplitude vibrations such as normal idling vibrations (periodic idling fundamental vibrations such as secondary vibrations of engine explosions) that are problematic when the vehicle is stopped. Since the amount is small, the pressure fluctuation in the pressure receiving chamber 70 is transmitted to the intermediate chamber 92 due to the displacement within the range allowed for the upper movable rubber plate 76. As a result, even if the first orifice passage 74 is substantially closed, the pressure in the pressure receiving chamber 70 is prevented from becoming excessive, and the pressure fluctuation in the pressure receiving chamber 70 is transmitted to the intermediate chamber 92. Thus, an effective pressure fluctuation is generated in the intermediate chamber 92.

  At this time, the displacement rigidity of the lower movable rubber plate 84 is set so that the pressure variation in the intermediate chamber 92 cannot be absorbed with the amount of displacement allowed for the lower movable rubber plate 84. Accordingly, the fluid flow through the second orifice passage 96 is efficiently generated without the pressure fluctuation in the intermediate chamber 92 escaping to the equilibrium chamber 72. Incidentally, FIG. 4 shows a functional configuration of the engine mount 10 in this state as a model.

  That is, in such a state, the intermediate chamber 92 in which effective pressure fluctuations are generated similarly to the pressure receiving chamber 70 and the variable volume equilibrium chamber 72 are connected through the second orifice passage 96 tuned to the middle frequency range. It becomes the composition. Therefore, the fluid flow amount through the second orifice passage 96 can be sufficiently secured by the relative pressure fluctuation generated between the pressure receiving chamber 70 and the intermediate chamber 92 and the equilibrium chamber 72 when the vibration is input. Based on the resonance action of the fluid flowing through the orifice passage 96, an effective anti-vibration effect (vibration insulation effect based on the low dynamic spring action) with respect to the idling fundamental vibration is exhibited.

  Further, when high-frequency small-amplitude vibrations such as running-over noise, which is a problem when the automobile is running, a pressure fluctuation with a small amplitude is generated in the pressure receiving chamber 70. The pressure fluctuation amount induced in the pressure receiving chamber 70 is allowed not only by the pressure fluctuation amount allowed by the displacement based on the elastic deformation of the upper movable rubber plate 76 but also by the displacement based on the elastic deformation of the lower movable rubber plate 84. The pressure fluctuation amount is almost the same or smaller. Thereby, the pressure fluctuation in the pressure receiving chamber 70 is transmitted to the intermediate chamber 92, and the pressure fluctuation in the intermediate chamber 92 is released to the equilibrium chamber 72.

  When a high frequency small amplitude vibration is input, both the first orifice passage 74 and the second orifice passage 96 have a remarkably large fluid flow resistance due to the anti-resonance action. It is blocked. Incidentally, FIG. 5 shows a functional configuration of the engine mount 10 in this state as a model.

  That is, in such a state, the pressure fluctuation in the pressure receiving chamber 70 is released to the equilibrium chamber 72, and the high dynamic spring due to the substantial blockage of the first and second orifice passages 96 is reduced or reduced. By avoiding this, a good anti-vibration effect (vibration insulation effect based on low dynamic spring characteristics) against high-frequency small-amplitude vibration is exhibited.

  Therefore, in the engine mount 10 having the above-described structure, the vibration isolation effect based on the resonance action of the fluid is effective against each of a plurality of types of vibrations having different amplitudes without providing an actuator or a control device. It can be demonstrated to.

  In the engine mount 10 of the present embodiment, the tuning of the first orifice passage 74 and the second orifice passage 96 and the tuning of the upper movable rubber plate 76 and the lower movable rubber plate 84 have been described above. It is not limited to the embodiment. Another specific tuning mode is shown below.

  That is, the resonance frequency (tuning frequency) of the fluid that is caused to flow through the second orifice passage 96 is tuned to a low frequency region around 10 Hz corresponding to rough idling vibration. Thereby, the tuning frequency of the first orifice passage 74 and the tuning frequency of the second orifice passage 96 are set in the same frequency range.

  At the same time, the allowable displacement amount of the upper movable rubber plate 76 is made larger than that in the above-described embodiment to sufficiently follow the pressure fluctuation caused in the pressure receiving chamber 70 when rough idling vibration is input. 70 pressure fluctuations are set so as to be transmitted to the intermediate chamber 92. Further, the allowable displacement amount of the lower movable rubber plate 84 is also made larger than in the case of the above embodiment, and sufficiently follows the pressure fluctuation transmitted from the pressure receiving chamber 70 to the intermediate chamber 92 when the idling basic vibration is input, The pressure fluctuation in the intermediate chamber 92 is set so that it can be transmitted to the equilibrium chamber 72 and escaped.

  In the engine mount that has been tuned as described above, in the case of low-frequency large-amplitude vibration such as engine shake that becomes a problem during traveling, the fluid that can flow through the first orifice passage 74 is the same as described above. The anti-vibration effect based on the resonance action is exhibited. At this time, a part of the pressure fluctuation induced in the pressure receiving chamber 70 escapes to the intermediate chamber 92 via the upper movable rubber plate 76. The pressure fluctuation induced in the intermediate chamber 92 causes the second orifice passage. Fluid flow through 96 will be generated. Here, since the second orifice passage 96 is tuned to a low frequency region substantially corresponding to the engine shake, the resonance action of the fluid flowing through the second orifice passage 96 is also combined. The anti-vibration effect against engine shake is demonstrated.

  Further, when low frequency medium amplitude vibration such as rough idling vibration, which is a problem when the automobile is stopped, most of the pressure fluctuations induced in the pressure receiving chamber 70 can escape to the intermediate chamber 92 via the upper movable rubber plate 76. However, the displacement rigidity of the lower movable rubber plate 84 is increased and the pressure fluctuation in the intermediate chamber 92 is prevented from escaping to the equilibrium chamber 72. Therefore, the amount of fluid flow through the second orifice passage 96 is ensured based on the pressure fluctuation induced in the intermediate chamber 92, and excellent against rough idling vibration based on the fluid action of this fluid. An anti-vibration effect (attenuation effect) can be exhibited.

  Furthermore, regarding the idling basic vibration which becomes a problem when the automobile is stopped, the pressure fluctuation caused in the pressure receiving chamber 70 is released from the intermediate chamber 92 to the equilibrium chamber 72 via the upper and lower movable rubber plates 76 and 84. Therefore, a significant increase in the dynamic spring due to the substantial closure of the first and second orifice passages 74 and 96 is avoided, and an excellent vibration isolation performance is exhibited based on the low dynamic spring action. is there.

  Incidentally, in the engine mount 10 of this embodiment subjected to such tuning, a low frequency large-amplitude vibration (amplitude is ± 0.5 mm) corresponding to an engine shake is obtained as a frequency characteristic of an attenuation coefficient: C in a low frequency region. FIG. 6 shows an evaluation when the input is performed and when the low-frequency medium amplitude vibration (amplitude is ± 0.3 mm) corresponding to the rough idling vibration is input. Note that the lower movable rubber plate 84 is simply disposed between the pressure receiving chamber 70 and the equilibrium chamber 72 without providing the intermediate chamber (92), the upper movable rubber plate (76), and the second orifice passage 96. For a fluid-filled engine mount equipped with a conventional hydraulic pressure absorption mechanism (for example, an engine mount described in Japanese Patent Application Laid-Open No. 64-49731), an attenuation coefficient in a low frequency region: C frequency characteristics are expressed in terms of engine shake. When a low-frequency large amplitude vibration (amplitude is ± 0.5 mm) corresponding to is input and a low-frequency medium amplitude vibration (amplitude is ± 0.3 mm) corresponding to rough idling vibration is input The result is as shown in FIG. The fluid-filled engine mount equipped with the conventional hydraulic pressure absorbing mechanism shows such a result, even when rough idling vibration is input, the pressure fluctuation induced in the pressure receiving chamber 70 is caused by the hydraulic pressure generated by the movable rubber plate. This is because it is absorbed by the absorption mechanism. From the graphs of the characteristics shown in FIG. 6 and FIG. 7, it is understood that the engine mount 10 of this embodiment is particularly effective against rough idling vibration.

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

  For example, in the above-described embodiment, one intermediate chamber 92 is provided. However, as shown as a model diagram in FIG. 8, two intermediate chambers 92 a and 92 b are provided between the pressure receiving chamber 70 and the equilibrium chamber 72. May be provided in series. For ease of understanding, members and parts having the same structure as in the above embodiment are given the same reference numerals as in the above embodiment in the drawings, and detailed description thereof is omitted. .

  In the engine mount 102 having such a structure, the side wall portion of the pressure receiving chamber 70 of one intermediate chamber 92a located on the pressure receiving chamber 70 side is constituted by the first movable rubber plate 104 as the input side movable plate, A side wall portion of the equilibrium chamber 72 of the intermediate chamber 92a is constituted by a second movable rubber plate 106 as an output side movable plate. Further, the side wall portion of the pressure receiving chamber 70 in the other intermediate chamber 92b located on the equilibrium chamber 72 side is constituted by the second movable rubber plate 106 as an input side movable plate, and the equilibrium chamber 72 of the other intermediate chamber 92b. The side wall portion is constituted by a third movable rubber plate 108 as an output side movable plate.

  That is, in the engine mount 102 shown in FIG. 8, the output side movable plate of one intermediate chamber 92a located on the pressure receiving chamber 70 side functions as the input side movable plate of the other intermediate chamber 92b located on the equilibrium chamber 72 side. It is supposed to do.

  Further, in the engine mount 102 shown in FIG. 8, the volume variable amount allowed with the displacement of the second movable rubber plate 106 is the volume variable amount allowed with the displacement of the first movable rubber plate 104. The effective area of the second movable rubber plate 106 is set to be smaller than the effective area of the first movable rubber plate 104 so as to be smaller than the first movable rubber plate 104 and is allowed as the third movable rubber plate 108 is displaced. The effective area of the third movable rubber plate 108 is such that the effective volume of the third movable rubber plate 106 is smaller than the volume variable amount allowed with the displacement of the second movable rubber plate 106. Is set smaller than the effective area.

  In the engine mount 102 of FIG. 8, the displacement amounts in the plate thickness direction allowed for the first, second, and third movable rubber plates 104, 106, and 108 are set to be substantially the same. However, the allowable displacement amount is set to be different from each other, the allowable displacement amount of the second movable rubber plate 106 is set smaller than that of the first movable rubber plate 104, and the allowable displacement amount of the third movable rubber plate 108 is set smaller. May be. When such permissible displacement amounts are relatively different, the effective areas of the first, second, and third movable rubber plates 104, 106, and 108 can be made substantially the same.

  Further, in the engine mount 102 shown in FIG. 8, for example, the resonance frequency (tuning frequency) of the fluid that flows through the first orifice passage 74 that communicates the pressure receiving chamber 70 and the equilibrium chamber 72 with each other is the engine shake vibration. The resonance frequency (tuning frequency) of the fluid that is tuned to the corresponding low frequency region of about 10 Hz and made to flow through the second orifice passage 96a serving as a sub-orifice passage that connects the intermediate chamber 92a and the equilibrium chamber 72 to each other. ) Is tuned to a low frequency range of about 10 Hz corresponding to rough idling vibration, and is further caused to flow through a third orifice passage 96b as a sub-orifice passage communicating with the other intermediate chamber 92b and the equilibrium chamber 72. Fluid resonance frequency (tuning frequency Number) is tuned to the frequency range in the order of the corresponding example 20Hz to normal idling fundamental vibration.

  Note that the tuning frequencies of the first to third orifice passages 74, 96a, and 96b are not limited to those described above. For example, the first orifice passage 74 is placed in a low frequency region of engine shake vibration. In addition to tuning, the second orifice passage 96a may be tuned to a mid-frequency range of normal idling vibration, and the third orifice passage 96b may be tuned to a high-frequency range such as a traveling boom noise.

  Also in such an engine mount 102, since the displacement amounts of the first to third movable rubber plates 104, 106, 108 are set appropriately, a plurality of types of vibrations having different amplitudes as in the above embodiment. Therefore, the vibration isolation effect based on the resonance action of the fluid flowing through the orifice passages 74, 96a, and 96b can be effectively exhibited.

  In the embodiment, the plurality of support protrusions 80 on the upper movable rubber plate 76 and the plurality of support protrusions 88 on the lower movable rubber plate 84 are not necessarily provided. May be held under pressure over the entire circumference, or the outer peripheral edge of the lower movable rubber plate 84 may be held under pressure over the entire circumference. Furthermore, in the above embodiment, the outer peripheral edge portion of the input side movable plate may not be constrained, and the entire input side movable plate may be displaced, or the outer peripheral edge portion of the output side movable plate may be The entire output side movable plate may be displaced without being constrained.

  In addition, in the above-described embodiment, a specific example in which the present invention is applied to an engine mount for an automobile is shown. However, the present invention is not limited to an automobile body mount, a differential mount, a suspension member mount, etc. Of course, the present invention can also be applied to the various vibration isolators.

  Moreover, in the said embodiment, although the reinforcement metal fittings 82 and 90 were fixed to the upper and lower movable rubber plates 76 and 84, such a reinforcement metal fitting is not essential. In particular, in the above embodiment, the annular plate-shaped reinforcing metal fittings 82 and 90 having a through hole formed in the central portion are employed, and the through hole in the central portion is closed with a rubber elastic film. However, you may employ | adopt the reinforcement metal fitting in which the through-hole of such a center part is not formed. However, in the movable rubber plates 76 and 84 having a structure in which the through hole in the central portion is closed with a rubber elastic film, the pressure receiving chamber at the time of vibration input in a higher frequency range than the tuning frequency range of the main orifice passage and the sub-orifice passage. In addition, by absorbing the pressure fluctuation in the intermediate chamber by the elastic deformation of the rubber elastic membrane that closes the through hole in the central portion, it is possible to enjoy the effect of avoiding a significant high dynamic spring.

  In addition, although not listed 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 as one Embodiment of this invention. Model diagram of the engine mount. The model figure for demonstrating the functional structure of the engine mount at the time of a low frequency large amplitude vibration input. The model figure for demonstrating the functional structure of the engine mount at the time of medium frequency medium amplitude vibration input. The model figure for demonstrating the functional structure of the engine mount at the time of a high frequency small amplitude vibration input. The graph which shows the frequency characteristic of the attenuation coefficient of the low frequency area in the engine mount of this embodiment The graph which shows the frequency characteristic of the attenuation coefficient of the low frequency region in the engine mount of the conventional structure. FIG. 3 is a model diagram showing an engine mount as a fluid-filled vibration isolator according to the present invention, in which two intermediate chambers are arranged in series between a pressure receiving chamber and an equilibrium chamber.

Explanation of symbols

10: Engine mount, 16: Main rubber elastic body, 28: Diaphragm, 70: Pressure receiving chamber, 72: Equilibrium chamber, 74: First orifice passage, 76: Upper movable rubber plate, 84: Lower movable rubber plate, 92 : Intermediate chamber, 96: Second orifice passage

Claims (5)

A pressure receiving chamber in which an incompressible fluid is sealed, in which a part of the wall portion is formed of a main rubber elastic body, and pressure fluctuation is caused at the time of vibration input;
A variable volume equilibration chamber in which a part of the wall is made of a flexible membrane and in which an incompressible fluid is enclosed;
A main orifice passage communicating the pressure receiving chamber and the equilibrium chamber with each other;
An intermediate chamber formed separately from the pressure receiving chamber and the equilibrium chamber and filled with an incompressible fluid;
The pressure from the pressure receiving chamber is disposed on the wall portion of the intermediate chamber and displaced on the surface opposite to the intermediate chamber to displace the pressure from the pressure receiving chamber to the intermediate chamber. An input-side movable plate with limited displacement that causes pressure fluctuations in the intermediate chamber;
Displaced more than the input-side movable plate, disposed on the wall of the intermediate chamber separately from the input-side movable plate, to transmit the pressure fluctuation of the intermediate chamber to the equilibrium chamber and to release the pressure fluctuation of the intermediate chamber An output-side movable plate whose displacement is limited so that the allowable volume variable amount is reduced along with,
A fluid-filled vibration isolator having a sub-orifice passage communicating the intermediate chamber and the equilibrium chamber with each other.   The fluid-filled vibration isolator according to claim 1, wherein an effective area of the output movable plate is smaller than an effective area of the input movable plate.   The fluid-filled vibration isolator according to claim 1 or 2, wherein the main orifice passage and the sub-orifice passage are tuned to the same frequency range.   One intermediate chamber is provided, the input side movable plate is disposed between the pressure receiving chamber and the intermediate chamber, and the pressure of the pressure receiving chamber is exerted on one surface of the input side movable plate. At the same time, the pressure of the intermediate chamber is applied to the other surface, and the input side movable plate is displaced based on the pressure difference between the pressure receiving chamber and the intermediate chamber, whereby the pressure fluctuation of the pressure receiving chamber is transmitted to the intermediate chamber. On the other hand, the output side movable plate is disposed between the intermediate chamber and the equilibrium chamber, and the output side movable plate is displaced based on a pressure difference between the intermediate chamber and the equilibrium chamber. The fluid-filled vibration isolator according to any one of claims 1 to 3, wherein pressure fluctuations in the intermediate chamber are allowed to escape to the equilibrium chamber.   A plurality of the intermediate chambers are provided in series between the pressure receiving chamber and the equilibrium chamber, and one of the two intermediate chambers arranged in series with each other is positioned on the pressure receiving chamber side. 5. The output side movable plate in the intermediate chamber functions as the input side movable plate in the other intermediate chamber positioned on the equilibrium chamber side. Fluid-filled vibration isolator.

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