JP5431982B2 - Liquid-filled vibration isolator - Google Patents

Description

  The present invention relates to a liquid-filled vibration isolator.

  As an anti-vibration device such as an engine mount that supports the vibration of a vibration source such as an automobile engine so as not to be transmitted to the vehicle body side, a first attachment attached to the vehicle body side, a second attachment attached to the vibration source side, An anti-vibration base made of a rubber-like elastic body interposed between the fixtures, a main liquid chamber in which the anti-vibration base forms part of the chamber wall, and a sub-liquid chamber in which the diaphragm forms part of the chamber wall; And an orifice channel that communicates between the liquid chambers, and is configured to perform a vibration damping function and a vibration insulation function by a liquid column resonance effect caused by a liquid flow in the orifice channel and a vibration damping effect of the vibration isolating substrate. A liquid-filled vibration isolator is known.

  Further, for example, as shown in Patent Document 1 below, in order to exhibit a high damping performance at the time of relatively large amplitude input due to the liquid flow effect in the orifice flow path, and a low dynamic spring characteristic at the time of fine amplitude input, A structure in which an elastic membrane made of a rubber-like elastic body is provided is also known.

  As a liquid-filled vibration isolator, in Patent Document 2 below, an elastic plate (elastic membrane) is provided in a partition body that partitions the main liquid chamber and the sub liquid chamber, and a cut is formed through the elastic plate. Constructs a common valve for the tension and compression stages, avoids extreme positive pressure and extreme negative pressure conditions in the main fluid chamber by opening and closing this valve, and suppresses unpleasant noise and noise caused by cavitation Is disclosed.

  Further, in Patent Document 3 below, a main rubber chamber is provided by disposing a closing rubber elastic plate from the side of the secondary liquid chamber with respect to the partition member and constraining the outer peripheral portion of the closing rubber elastic plate at a plurality of locations on the circumference. A structure is disclosed in which liquid is leaked from the non-restraining portion of the closed rubber elastic plate when an excessive positive pressure is generated in the case.

JP 2006-057727 A Japanese Patent Publication No. 7-107416 JP 2009-133453 A

  In the structure of the above-mentioned patent document 2, not only the input on the compression side (that is, the positive pressure side of the main liquid chamber) but also the notch provided in the elastic plate at the time of input on the tension side (that is, the negative pressure side of the main liquid chamber). Therefore, it is difficult to ensure the damping performance due to the liquid flow in the orifice channel. On the other hand, in the structure of Patent Document 3, in order to partially restrain the outer peripheral portion of the closing rubber elastic plate, it is necessary to incorporate a leaf spring member inside the closing rubber elastic plate, which increases the cost.

  By the way, in the structure in which an elastic membrane is incorporated in the partition for the purpose of relaxing the pressure of the main liquid chamber, the elastic membrane design that can withstand the excessive positive pressure generation in the main liquid chamber in order to ensure the durability of the elastic membrane Is required. On the other hand, in order to increase the pressure relaxation effect by the elastic membrane and reduce the dynamic spring constant, it is required to reduce the rigidity of the elastic membrane (for example, lower hardness, thinner wall, larger diameter, etc.). Stiffening increases the deformation of the elastic membrane when excessive positive pressure is generated, impairing durability. As described above, conventionally, it has been difficult to reduce the rigidity of the elastic membrane in order to achieve a design that can withstand the generation of excessive positive pressure, and there has been a restriction on the reduction of the dynamic spring constant.

  The present invention has been made in view of the above points, and can suppress an excessive positive pressure state in the main liquid chamber while ensuring a damping performance in a normal use region, and can achieve low movement by an elastic membrane. An object of the present invention is to provide a liquid-filled vibration isolator capable of achieving both spring characteristics and durability.

  The liquid-filled vibration isolator according to the present invention includes a first fixture that is attached to one of the vibration source side and the support side, a second fixture that is attached to the other of the vibration source side and the support side, and the first attachment. An anti-vibration base made of a rubber-like elastic body interposed between the fixture and the second fixture, a main liquid chamber in which a liquid forming a part of a chamber wall of the anti-vibration base is enclosed, and rubber-like elasticity A diaphragm made of a membrane includes at least one sub liquid chamber in which a liquid forming a part of a chamber wall is sealed, and a first orifice channel that connects the main liquid chamber and one of the sub liquid chambers. The partition body that partitions the main liquid chamber and any one of the sub liquid chambers includes an elastic membrane made of a rubber-like elastic body that partitions the sub liquid chamber and the main liquid chamber, and the sub liquid chamber and the main liquid chamber. And a second orifice channel that is tuned to a higher frequency range than the first orifice channel and is provided with a rubber-like elastic film at the opening of the second orifice channel toward the secondary liquid chamber. A second diaphragm is provided. The second diaphragm is held in contact with the peripheral edge of the opening so that the outer peripheral portion is liquid-tight with respect to the partition body and the opening is closed by a flexible film portion inside the outer peripheral portion. The flexible film portion is provided with a through hole at a position that does not overlap the opening.

  In such a liquid-filled vibration isolator, in the normal use region, the flexible membrane portion of the second diaphragm comes into contact with the opening of the second orifice channel toward the sub liquid chamber side to block the opening. Therefore, liquid leakage from this portion can be prevented. When the flow rate of the second orifice channel becomes a predetermined amount or more, the flexible film portion is bent and deformed so as to be separated from the opening of the second orifice channel toward the sub liquid chamber side. The liquid can be supplied from the through hole provided in the film part to the sub liquid chamber side.

  Therefore, in the normal use region, a high damping performance can be exhibited by the flow of liquid through the first orifice channel on the low frequency side with respect to vibration input having a relatively large amplitude and a low frequency region. In addition, for vibration input with a relatively small amplitude and a high frequency range, the second diaphragm is slightly deformed while maintaining the closed state with respect to the opening, so that the liquid in the second orifice flow channel on the high frequency side is reduced. The anti-vibration effect with respect to the vibration of the high frequency range can be exhibited by the flow.

  On the other hand, when the flow rate of the second orifice channel reaches a predetermined amount or more due to the large amplitude input to the vibration isolator, the flexible membrane portion of the second diaphragm moves from the opening of the second orifice channel to the sub liquid chamber side. It bends and deforms so as to be separated. As a result, the liquid is supplied from the through hole provided in the flexible membrane portion to the side of the sub liquid chamber, so that it is possible to relieve pressure against excessive positive pressure generation in the main liquid chamber.

  As described above, in the normal use region, the second diaphragm having a role as a diaphragm for generating a liquid flow in the second orifice channel is used for pressure relaxation when the flow rate of the second orifice channel reaches a predetermined amount. It is used as a valve. Thus, since the excessive positive pressure generation in the main liquid chamber can be suppressed by the valve configuration by the second diaphragm, it is no longer necessary to design the elastic membrane to withstand the excessive positive pressure generation. Therefore, it is possible to reduce the rigidity of the elastic membrane without impairing durability, and low dynamic spring characteristics can be easily realized.

  As another aspect of the present invention, an opposing wall is provided on the secondary liquid chamber side of the second diaphragm so as to be opposed to the film surface of the flexible film portion on the side of the secondary liquid chamber. The flexible film part may be provided with a protrusion that is compressed between the opposing wall on the film surface on the side of the secondary liquid chamber at a position that does not overlap the opening of the partition. In this way, the rigidity of the second diaphragm can be changed by compressing the projection provided on the side of the secondary liquid chamber of the flexible membrane portion with the opposing wall, so that it is separated from the opening of the second orifice channel. The timing to do can be easily adjusted. Therefore, for example, the rigidity of the membrane portion that closes the opening of the second orifice channel is reduced, the characteristics of the second orifice channel on the high frequency side are improved, and the protrusion is suppressed while suppressing the impact when the second diaphragm is returned. The compression timing can delay the timing of separating from the opening of the second orifice channel.

  As another aspect according to the present invention, an annular protrusion is provided on the peripheral surface of the opening of the partition or the film surface on the main liquid chamber side of the flexible film facing the peripheral edge so as to surround the opening. It may be provided. By providing such an annular protrusion, the liquid flow in the second orifice channel until the flow rate of the second orifice channel reaches a predetermined amount, the second diaphragm and the opening of the second orifice channel The liquid tightness between them can be made more reliable.

  As another aspect of the present invention, the flexible membrane portion has a central portion in the radial direction as a plug portion that closes the opening, and has one or more through holes radially outward of the plug portion. be able to. Thereby, the supply of the liquid to the sub liquid chamber side when the second diaphragm is bent and deformed can be made smoother.

  In this case, the flexible membrane portion is arranged in parallel at a plurality of locations on the circumference where the through holes surround the plug portion, and the protrusions are provided alternately with the through holes at a plurality of locations on the circumference. May be. By providing a plurality of protrusions alternately on the circumference with the through holes in this way, the rigidity of the second diaphragm with respect to the bending deformation can be equalized on the circumference, and the timing of separating from the opening of the second orifice channel can be adjusted. Becomes even easier.

  As another aspect of the present invention, in the sub liquid chamber connected to the main liquid chamber by the second orifice channel, a diaphragm forming a partition wall with an air chamber or outside air forms a part of the chamber wall. It may be a secondary liquid chamber. The sub liquid chamber, which has a diaphragm facing the air chamber or the outside air as a part of the chamber wall, has a large pressure difference with the main liquid chamber, so that the sub liquid chamber and the main liquid chamber are connected to each other. The pressure relaxation effect can be enhanced by incorporating the valve configuration of the second diaphragm in the two-orifice channel.

  As another aspect of the present invention, the first fixture has a cylindrical shape, and the second fixture is disposed on the axial center portion of the first fixture, while the second fixture is attached to the first fixture. A first diaphragm made of a rubber-like elastic film that forms a liquid sealing chamber between the first fixture and the vibration isolating substrate, and the partition member connects the liquid sealing chamber to the vibration isolating substrate side. A main liquid chamber and a sub-liquid chamber on the first diaphragm side, the first orifice channel is provided on the outer periphery of the partition body to connect the main liquid chamber and the sub-liquid chamber, and the elastic membrane The main liquid chamber and the auxiliary liquid chamber are partitioned in the partition portion inside the outer peripheral portion, and the second orifice flow path is separated from the main liquid chamber in the partition portion inside the outer peripheral portion. The secondary liquid chambers may be connected to each other. Also in this case, since the first diaphragm forming a part of the chamber wall of the auxiliary liquid chamber faces the air chamber or the outside air, it is advantageous for enhancing the pressure relaxation effect.

  According to the present invention, in the normal use region, while exhibiting the damping performance against the vibration in the low frequency range due to the first orifice channel and the anti-vibration effect against the vibration in the high frequency range due to the second orifice channel, It is possible to suppress an excessive positive pressure state in the main liquid chamber, and it is possible to achieve both a low dynamic spring characteristic and durability due to the elastic membrane.

1 is a longitudinal sectional view of a liquid-filled vibration isolator according to a first embodiment. Sectional drawing of the partition body of the embodiment (A) Bottom view of the partition body of the partition body, (b) Plan view of an integrally molded product of the elastic membrane and the second diaphragm, (c) Plan view of the fixing member Expanded cross-sectional view of the main part of the partition (normal use area) The principal part expanded sectional view of the partition (at the time of bending deformation of the 2nd diaphragm) The 2nd diaphragm of the same embodiment is represented, (a) is a top view, (b) is the aa sectional drawing. The principal part expanded sectional view of the partition body concerning a 2nd embodiment. The 2nd diaphragm which concerns on 2nd Embodiment is represented, (a) is a top view, (b) is a bottom view, (c) The bb sectional view taken on the line. The 2nd diaphragm which concerns on 3rd Embodiment is represented, (a) is a top view, (b) is a bottom view, (c) The cc sectional view taken on the line c-c The principal part expanded sectional view of the liquid enclosure type vibration isolator which concerns on 4th Embodiment

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

[First Embodiment]
FIG. 1 is a longitudinal sectional view of a liquid-filled vibration isolator 10 according to an embodiment. The vibration isolator 10 is an engine mount that supports an automobile engine, and includes a lower first mounting member 12 that forms a cylindrical shape that is attached to a support-side vehicle body, and an upper side that is attached to an engine side that is a vibration source. The second fixture 14 is provided with a vibration-proof base 16 made of a rubber elastic body that is interposed between the fixtures 12 and 14 and connects them.

  The 2nd fixture 14 is the boss | hub metal fitting distribute | arranged above the axial center part of the 1st fixture 12, and the stopper part 18 which protrudes in a flange shape toward radial direction outward is formed. Moreover, the bolt hole 20 is provided in the upper end part, and it is comprised so that it may attach to an engine side via a volt | bolt not shown.

  The first fixture 12 includes a cylindrical tubular fitting 22 on which a vibration-proof base 16 is vulcanized and a cup-like bottom fitting 24, and a downward mounting bolt 26 projects from the center of the bottom fitting 24. It is configured to be attached to the vehicle body side via the bolt 26. The lower end of the cylindrical fitting 22 is fixed by caulking to the upper end opening of the bottom fitting 24 by a caulking portion 28. Reference numeral 30 denotes a stopper fitting fixed by caulking to the upper end portion of the cylindrical fitting 22, and exerts a stopper action with the stopper portion 18 of the second fixture 14. Reference numeral 32 denotes a stopper rubber that covers the upper surface of the stopper fitting 30.

  The anti-vibration base 16 is formed in a truncated cone shape, and its upper end is vulcanized and bonded to the second fixture 14 and its lower end is vulcanized and bonded to the upper end opening of the cylindrical fitting 22. A rubber film-like seal wall portion 34 covering the inner peripheral surface of the cylindrical metal fitting 22 is connected to the lower end portion of the vibration isolation base 16.

  The first fixture 12 includes a first diaphragm 38 made of a flexible rubber film that is disposed to face the lower surface of the vibration-isolating base 16 in the axial direction X and forms a liquid sealing chamber 36 between the lower surface. A liquid enclosure chamber 36 is filled with a liquid such as water, ethylene glycol, or silicone oil. The first diaphragm 38 includes an annular reinforcing metal fitting 39 on the outer peripheral portion, and is fixed to the caulking portion 28 via the reinforcing metal fitting 39.

  The liquid sealing chamber 36 provided inside the first fixture 12 is divided into a main liquid chamber 42 on the side of the vibration isolation base 16 (that is, the upper side) and a first diaphragm 38 side (that is, the lower side) by the partition body 40. ) Of the secondary liquid chamber 44. The main liquid chamber 42 is a liquid chamber in which the vibration isolation base 16 forms a part of the chamber wall, and the sub liquid chamber 44 is a liquid chamber in which the first diaphragm 38 forms a part of the chamber wall. An air chamber 46 is provided below the first diaphragm 38 inside the bottom metal fitting 24. Therefore, the first diaphragm 38 is a diaphragm that forms a partition wall between the sub-liquid chamber 44 and the air chamber 46.

  The partition body 40 has a circular shape in a plan view, and is fitted inside the cylindrical metal fitting 22 via a seal wall portion 34, and is made of a rigid material such as resin or metal. A ring-plate-shaped partition receiving plate 48 is disposed in contact with the lower surface of the partition body 40. The partition receiving plate 48 is fixed together with the reinforcing metal fitting 39 of the first diaphragm 38 by the caulking portion 28, thereby separating the partition. The body 40 is held in a state of being sandwiched in the axial direction X between the step portion 34 </ b> A provided on the seal wall portion 34 and the partition receiving plate 48.

  The partition body 40 is provided with a first orifice channel 50 which is a throttle channel, and the main liquid chamber 42 and the sub liquid chamber 44 are communicated with each other via the first orifice channel 50. In this example, the first orifice channel 50 is a low frequency side orifice tuned to a low frequency range (for example, about 5 to 15 Hz) corresponding to the shake vibration in order to attenuate the shake vibration during vehicle travel. That is, tuning is performed by adjusting the cross-sectional area and length of the flow path so that the damping effect based on the resonance action of the liquid flowing through the first orifice flow path 50 is effectively exhibited when the shake vibration is input. .

  The first orifice channel 50 is provided on the outer peripheral side of the partition body 40. More specifically, a circumferential direction C (FIG. 3) is formed between the first orifice forming groove 52 (see FIG. 2) opened outward and provided in the outer peripheral portion 40A of the partition body 40 and the seal wall portion 34. A first orifice channel 50 extending in (a) is formed. As shown in FIG. 3A, the first orifice passage 50 includes a main liquid chamber side opening 50 </ b> A that opens to the main liquid chamber 42 at one end in the circumferential direction C and the other end in the circumferential direction C. An orifice channel in a normally connected state that includes a secondary liquid chamber side opening 50B that opens to the secondary liquid chamber 44 and communicates with both the main liquid chamber 42 and the secondary liquid chamber 44 without being blocked at all times. It is.

  The partition body 40 is also provided with an elastic membrane 54 made of a rubber film for the purpose of relaxing the pressure in the main liquid chamber 42. The elastic membrane 54 partitions the main liquid chamber 42 and the sub liquid chamber 44 on the inner peripheral side of the partition body 40 (that is, the partition body portion radially inward of the outer peripheral portion 40A).

  The elastic membrane 54 has a disk shape (circular film shape), and the outer peripheral portion 54A has a thick wall shape over the entire circumference, and includes a flexible portion 54B thinner than the outer peripheral portion 54A on the inner side. . In this example, as shown in FIGS. 2 and 3B, the elastic membrane 54 is provided integrally with a second diaphragm 72 described later.

  In the elastic membrane 54, the outer peripheral portion 54A is liquid-tightly held by the partition body 40 over the entire periphery, and the flexible portion 54B inside the outer peripheral portion 54A has one membrane surface (upper surface). The pressure of the main liquid chamber 42 is exerted, and the pressure of the sub liquid chamber 44 is exerted on the other film surface (lower surface).

  Therefore, the partition body 56 that holds the elastic membrane 54 is provided with an opening 58 that opens to the main liquid chamber 42 side corresponding to the flexible portion 54B, and an outer peripheral portion 54A is disposed around the opening 58. An annular groove 60 is provided. Further, a fixing member 62 for holding and fixing the elastic membrane 54 between the partition body main body 56 is provided. The fixing member 62 is made of a rigid material such as resin or metal, and has an opening 64 that opens to the sub liquid chamber 44 side corresponding to the flexible portion 54B. The fixing member 62 is internally fitted and fixed to a step portion 66 provided around the annular groove 60 of the partition body 56, whereby the outer peripheral portion 54 </ b> A of the elastic membrane 54 is pivoted between the annular groove 60. It is configured to be held in a state compressed in the direction X.

  In this example, no displacement restricting members for restricting excessive displacement of the elastic membrane 54 are provided on both upper and lower sides of the elastic membrane 54.

  The partition body 40 is also provided with a second orifice channel 68 which is a throttle channel, and the main liquid chamber 42 and the sub liquid chamber 44 are communicated with each other via the second orifice channel 68. . The second orifice channel 68 is a high-frequency side orifice tuned in a higher frequency range than the first orifice channel 50. In this example, in order to reduce idling vibration during idling (when the vehicle is stopped), idling vibration is used. Is tuned to a high frequency range (for example, about 15 to 50 Hz). That is, it is tuned by adjusting the cross-sectional area and length of the flow path so that the low dynamic spring effect based on the resonance action of the liquid flowing through the second orifice flow path 54 is effectively exhibited when the idle vibration is input. ing.

  As shown in FIG. 2, the second orifice channel 68 is formed in the thickness direction of the partition body 40 (this example) on the inner peripheral side of the partition body 40 (that is, the partition body portion radially inward of the outer peripheral portion 40A). Then, it is provided so as to extend in the axial direction X and penetrate the partition body 40. Specifically, a stepped recess 70 having a circular shape in plan view is provided on the lower surface of the partition body 56 (see FIG. 3A), and a circular through hole is provided in the center of the stepped recess 70. Thus, the second orifice channel 68 is formed.

  In the stepped recess 70 of the partition body 40, a second diaphragm 72 made of a flexible rubber film is provided in the opening 68A on the side of the secondary liquid chamber 44 of the second orifice channel 68. As shown in FIG. 4, in the second diaphragm 72, the outer peripheral portion 72A is held in a liquid-tight manner over the entire periphery with respect to the partition body 40, and the flexible membrane portion 72B inside the outer peripheral portion 72A opens the opening. 68A is provided in contact with the peripheral edge of the opening so as to close the auxiliary liquid chamber 44 from the side.

  Specifically, as shown in FIG. 6, the second diaphragm 72 has a disk shape (circular film shape), and the outer peripheral portion 72A is thick on the entire circumference, and the inner side of the thick outer peripheral portion 72A. Is provided with a flexible film portion 72B having a circular thin film shape. The flexible film portion 72B is formed so as to block between the inner peripheral surfaces of the outer peripheral portion 72A at an intermediate position in the thickness direction of the outer peripheral portion 72A.

  In this example, the second diaphragm 72 is formed integrally with the elastic membrane 54. Specifically, the outer peripheral portions 72A and 54A are integrated with each other in a shape where they are connected to each other. Therefore, as shown in FIG. I am doing. As shown in FIG. 2, the flexible membrane portion 72 </ b> B of the second diaphragm 72 is formed thinner than the flexible portion 54 </ b> B of the elastic membrane 54.

  Further, the stepped recess 70 of the partition body 40 is provided with an annular groove 74 in which the outer peripheral portion 72A of the second diaphragm 72 is disposed, and the flexible film portion 72B of the second diaphragm 72 is in contact with the inner side thereof. A raised portion 76 having a flat upper surface and a circular shape is provided. In this example, since the second diaphragm 72 is provided integrally with the elastic membrane 54, the annular groove 74 that receives the outer peripheral portion 72A is connected to the annular groove 60 that receives the outer peripheral portion 54A of the elastic membrane 54. (Refer to FIG. 3A). Further, a step 78 provided around the annular groove 74 is also connected to a step 66 provided around the annular groove 60 for the elastic membrane 54.

  The second diaphragm 72 disposed in the stepped recess 70 is clamped and fixed to the partition body 56 by the fixing member 62. That is, the fixing member 62 serves as a fixing means not only for the elastic membrane 54 but also for the second diaphragm 72. Therefore, it is also fitted and fixed to the stepped portion 78 around the annular groove 74, and the outer peripheral portion 72A of the second diaphragm 72 is sandwiched between the annular groove 74 in a state compressed in the axial direction X. The outer peripheral portion 72A is held liquid-tight (that is, the liquid does not leak).

  As shown in FIG. 3C, the fixing member 62 has a circular opening 80 corresponding to the flexible membrane portion 72B. Therefore, the fixing member 62 is located below the flexible membrane portion 72B (sub-liquid chamber 44). On the side), there is no wall part that restricts the deformation of the flexible film part 72B. Further, a ring-shaped protrusion 82 that protrudes toward the main liquid chamber 42 side and presses the outer peripheral edge of the flexible film portion 72B is provided at the peripheral portion of the opening 80, and the outer peripheral portion 72A of the second diaphragm 72 is provided. The inner displacement of the outer peripheral portion 72A is restricted in contact with the inner peripheral surface (see FIG. 4).

  In the second diaphragm 72 incorporated in the partition body 40 in this way, the flexible film portion 72B is pressed against the lower surface of the raised portion 76 of the stepped recess 70, whereby the second orifice channel 68 is The opening 68A is blocked. The flexible membrane portion 72B closes the opening 68A at its radial center, and therefore the radial center that closes the opening 68A serves as a plug portion 84.

  The flexible membrane portion 72B includes at least one through hole 86 so as not to overlap with the opening 68A of the second orifice channel 68, that is, when viewed from the axial direction X. The through holes 86 are arranged in parallel at a plurality of locations on the circumference surrounding the plug portion 84 located at the center of the flexible membrane portion 72B. In this example, four circular through holes are equally spaced. 86 is provided.

  In the liquid-filled vibration isolator 10 having the above-described configuration, in the normal use region where the absolute value of the liquid pressure in the main liquid chamber 42 is not more than a specified value, the flexible film portion 72B of the second diaphragm 72 is The opening 68 </ b> A is abutted against the opening 68 </ b> A of the second orifice channel 68. Therefore, liquid leakage from this portion can be prevented in the normal use region. On the other hand, when the fluid pressure in the main fluid chamber 42 becomes larger than the specified value and the flow rate in the second orifice channel 68 becomes a predetermined amount or more, as shown in FIG. The diaphragm 72 has its inner flexible membrane portion 72B pressed against the secondary liquid chamber 44 side by liquid flow, so that the secondary liquid chamber 44 side (ie, downward) from the opening 68A of the second orifice channel 68 is obtained. It bends and deforms so as to be separated. Thereby, the liquid in the main liquid chamber 42 can escape to the side of the sub liquid chamber 44 through the through hole 86 provided in the flexible film part 72B. In addition, since the inflow of the liquid from the sub liquid chamber 44 to the 2nd orifice flow path 68 is blocked | prevented by the 2nd diaphragm 72, the flexible membrane part 72B functions as a non-return valve.

  Therefore, with the liquid-filled vibration isolator 10, in the normal use region, when vibration on the low frequency side with a relatively large amplitude, such as shake vibration, is input during vehicle travel, the liquid in the second diaphragm 72 Since liquid flows back and forth between the main liquid chamber 42 and the sub liquid chamber 44 via the first orifice channel 50 on the low frequency side while preventing leakage, the resonance action of the liquid flowing through the first orifice channel 50 Based on the above, high damping performance is exhibited against shake vibration.

  Further, when vibration on the high frequency side is input with a relatively small amplitude, such as during idling when the vehicle is stopped, the second diaphragm 72 maintains a closed state with respect to the opening 68A of the second orifice channel 68 with a small amplitude. Due to the bending deformation, the liquid flows in the second orifice flow path 68 on the high frequency side, and the resonance action of the liquid through the second orifice flow path 68 on the high frequency side has an excellent anti-vibration effect against idle vibration. Demonstrated.

  Further, in such a normal use region, the elastic membrane 54 provided in the partition body 40 is bent and deformed based on the pressure fluctuation between the main liquid chamber 42 and the sub liquid chamber 44, thereby reducing the pressure in the main liquid chamber 42. Thus, for example, it is possible to reduce the dynamic spring constant in the booming sound region, which is a higher frequency region than idle vibration.

  On the other hand, when a large-amplitude input is generated, such as over a road surface step, and the flow rate of the second orifice flow path 68 reaches a predetermined amount or more, the flexible film portion 72B of the second diaphragm 72 causes the second orifice flow. It bends and deforms so as to be separated from the opening 68A of the passage 68 toward the auxiliary liquid chamber 44. Thereby, since the liquid is supplied from the through hole 86 provided in the flexible film part 72B to the sub liquid chamber 44 side, the pressure can be relieved against excessive positive pressure generation in the main liquid chamber 42. Therefore, excessive bending deformation of the elastic membrane 54 can be suppressed.

  As described above, in the vibration isolator 10 according to the present embodiment, the second diaphragm 72 having a role as a diaphragm for generating a liquid flow in the second orifice channel 68 in the normal use region is provided as the second orifice channel 68. It is used as a valve for pressure relief when the flow rate of the gas reaches a predetermined amount. Therefore, the number of parts can be reduced and the structure can be simplified, leading to cost reduction.

  In addition, since the generation of excessive positive pressure in the main liquid chamber 42 can be suppressed, the elastic membrane 54 no longer needs to be designed to withstand the generation of excessive positive pressure. Therefore, the rigidity of the elastic membrane 54 can be reduced without impairing durability, and low dynamic spring characteristics can be easily realized.

  When the flow rate of the second orifice channel 68 reaches a predetermined amount or less after the separation, the second diaphragm 72 comes into contact again with the opening 68A of the second orifice channel 68, but its restoring force is This is due to rubber elasticity, and since the impact associated with the return is small, it is difficult to generate an abnormal noise associated with the return.

  Further, according to the present embodiment, the flexible membrane portion 72B of the second diaphragm 72 has the central portion in the radial direction as the plug portion 84 and the through hole 86 is provided in the radially outward direction. When the liquid crystal is bent and deformed, the gap between the opening 68A of the second orifice channel 68 and the plug member 84 can be secured large, and the supply of the liquid to the sub liquid chamber 44 side can be made smoother.

[Second Embodiment]
7 and 8 are diagrams related to the liquid-filled vibration isolator of the second embodiment. This example differs from the above embodiment in that a projection 88 is provided on the flexible film portion 72B of the second diaphragm 72.

  Specifically, as shown in FIG. 7, the opposing wall 90 facing the film surface of the flexible film portion 72 </ b> B on the side of the secondary liquid chamber 44 on the side of the secondary liquid chamber 44 is spaced apart from the film surface on the side of the secondary liquid chamber 44. Is provided. The facing wall 90 is provided integrally with the fixing member 62. Therefore, in this example, the fixing member 66 has an opposing wall 90 corresponding to the flexible film portion 72B, and a communication hole 92 that allows the secondary liquid chamber 44 and the second orifice channel 68 side to communicate with each other at the center thereof. The ring-shaped protrusion 82 is provided on the outer periphery of the opposing wall 78, and the outer peripheral portion 72A of the second diaphragm 72 is sandwiched on the outer peripheral side.

  Further, the flexible membrane portion 72B has a projection that is compressed between the opposing wall 90 on the membrane surface on the side of the secondary liquid chamber 44 at a position that does not overlap the opening 68A of the second orifice channel 68. 88 is provided. In this example, the projection 88 is configured to be compressed by being pressed against the opposing wall 90 in a state of being incorporated in the partition body 40.

  The protrusions 88 are provided only on the film surface on the side of the auxiliary liquid chamber 44 and, as shown in FIG. 8, form a cone, in this example, a cone, and have a plurality of locations on the same circumference as the through hole 86. (4 places in this example) are provided alternately with the through holes 86.

  In this way, the rigidity of the second diaphragm 72 can be changed by compressing the projection 88 provided on the sub liquid chamber 44 side of the flexible film portion 72B with the opposing wall 90, so that the second orifice The timing of separating from the opening 68A of the flow path 68 can be easily adjusted.

  Specifically, in order to improve the characteristics of the second orifice flow path 68 on the high frequency side, the rigidity of the membrane portion (the plug portion 84) that closes the opening 68A of the second orifice flow path 68 is reduced, so that the micro deformation However, if the rubber hardness is simply reduced for this purpose, the second diaphragm 72 is easily bent and deformed when a large amplitude is input, and the second diaphragm 72 is separated from the opening 68A of the second orifice channel 68 at an early stage. The original attenuation performance by the first orifice channel 50 may be impaired. On the other hand, if the projection 88 is provided, the rubber hardness is reduced and the plug portion 84 at the center is easily deformed minutely, and the peripheral portion thereof is increased in rigidity by the compression of the projection 88, so that the second The timing of separating from the opening 68A of the orifice channel 68 can be delayed. Further, if the rubber hardness can be reduced in this way, it is possible to suppress an impact when the second diaphragm 72 is returned, and it is possible to make it difficult to generate abnormal noise.

  Further, by providing the plurality of protrusions 88 alternately on the circumference with the through holes 86 as in the present embodiment, the rigidity of the second diaphragm 72 against the bending deformation can be made uniform on the circumference, and the second orifice Adjustment of the timing of separating from the opening 68A of the flow path 68 is further facilitated. Other configurations and operational effects are the same as those of the first embodiment, and a description thereof will be omitted.

[Third Embodiment]
FIG. 9 is a diagram relating to the liquid-filled vibration isolator of the third embodiment. This example differs from the second embodiment in that an annular protrusion 94 is provided on the flexible film portion 72B of the second diaphragm 72.

  That is, in this example, the film surface on the main liquid chamber 42 side of the flexible film portion 72B facing the peripheral edge portion of the opening 68A of the second orifice channel 68 extends over the entire circumference so as to surround the opening 68A. An annular protrusion 94 is provided. The annular protrusion 94 is provided in a circular shape in plan view along the outer peripheral portion of the plug portion 84 corresponding to the central portion of the flexible film portion 72B, and is provided radially inward from the through hole 86 and the protrusion 88. It has been.

  When the second diaphragm 72 is brought into contact with the opening 68 </ b> A of the second orifice channel 68, the annular protrusion 94 functions as a seal protrusion that seals around the opening. Therefore, with respect to the liquid flow in the second orifice channel 68 until the flow rate of the second orifice channel 68 reaches a predetermined amount, the flow between the second diaphragm 72 and the opening 68A of the second orifice channel 68 is reduced. The liquid tightness can be made more reliable. Other configurations and operational effects are the same as those of the second embodiment, and a description thereof will be omitted.

[Fourth Embodiment]
FIG. 10 is a diagram relating to the liquid-filled vibration isolator of the fourth embodiment. This example differs from the first embodiment in that the elastic membrane 54 and the second diaphragm 72 are provided separately.

  That is, in this example, the elastic membrane 54 and the second diaphragm 72 are each formed in a circular shape as separate members, and both the members 54 and 72 are respectively attached to the recesses on the lower surface side of the partition body main body 56, and are shared. The fixing member 62 is fixed.

  As described above, the elastic membrane 54 and the second diaphragm 72 may be provided separately. However, in terms of reduction in the number of parts and assembling workability, it is preferable to integrally form both as in the above embodiment. Other configurations and operational effects are the same as those of the first embodiment, and a description thereof will be omitted.

[Other Embodiments]
The arrangement, number, and shape of the through holes 86 and the protrusions 88 provided in the second diaphragm 72 are not limited to the above-described embodiment, and various changes can be made. For example, in the above embodiment, the central portion of the flexible membrane portion 72B is the plug portion 84 that closes the opening 68A of the second orifice channel 68, and a plurality of through holes 86 are provided around it. The center of the flexible film portion 72B may be provided eccentric to one side, and the through hole 86 may be provided on the other side.

  Moreover, in the said embodiment, although the annular protrusion 94 was provided in the flexible membrane part 72B of the 2nd diaphragm 72, this annular protrusion can also be provided in the partition body 40 side. That is, an annular protrusion that protrudes toward the second diaphragm 72 may be provided on the peripheral edge of the opening 68A of the second orifice channel 68 so as to surround the opening 68A.

  In the above embodiment, the case where the liquid chamber includes the main liquid chamber 42 and the single sub liquid chamber 44 has been described. However, the liquid chamber has a plurality of sub liquid chambers together with the main liquid chamber, and the space between these liquid chambers is an orifice. The present invention can be similarly applied to various liquid-filled vibration isolators connected by flow paths. In this case, the sub liquid chamber communicated with the main liquid chamber via the first orifice flow path and the sub liquid chamber communicated with the main liquid chamber via the second orifice flow path may be the same or different. Moreover, you may provide the other orifice flow path which connects subliquid chambers.

  Preferably, as in the above-described embodiment, in the second orifice channel 68 that connects the sub-liquid chamber 44 and the main liquid chamber 42 with the first diaphragm 38 facing the air chamber 46 as a part of the chamber wall. The valve configuration of the second diaphragm 72 is incorporated. The secondary liquid chamber 44 having the first diaphragm 38 facing the air chamber 46 as a part of the chamber wall has a large pressure difference with the main liquid chamber 42, so that the flow rate of the second orifice channel 68 increases. Therefore, the pressure relaxation effect by the second diaphragm 72 can be enhanced. Also in this case, the sub liquid chamber connected to the main liquid chamber via the first orifice channel is the same as or different from the sub liquid chamber connected to the main liquid chamber via the second orifice channel. Also good. Further, the first diaphragm 38 may face the outside air instead of the air chamber 46.

  In the above embodiment, the shake vibration and the idle vibration are targeted. However, the present invention is not limited to this, and can be applied to various vibrations having different frequencies. Although not enumerated one by one, various modifications can be made without departing from the spirit of the present invention.

  The present invention can be used for various vibration isolators such as a mount that supports other power units such as a motor, a body mount, and a differential mount, in addition to an engine mount.

DESCRIPTION OF SYMBOLS 10 ... Liquid enclosure type vibration isolator 12 ... 1st fixture 14 ... 2nd fixture
16 ... Vibration-proof substrate, 36 ... Liquid enclosure, 38 ... First diaphragm,
40 ... partition body, 40A ... outer periphery of partition body, 42 ... main liquid chamber,
44 ... Secondary liquid chamber, 46 ... Air chamber, 50 ... First orifice channel,
54 ... elastic membrane, 68 ... second orifice channel, 68A ... opening on the secondary liquid chamber side,
72 ... 2nd diaphragm, 72A ... Outer peripheral part, 72B ... Flexible membrane part,
84 ... plug part, 86 ... through hole, 88 ... projection,
90 ... opposing wall, 94 ... annular projection,
X: axial direction, C: circumferential direction, L: spacing

Claims (8)

A first fixture attached to one of the vibration source side and the support side;
A second fixture attached to the other of the vibration source side and the support side;
An anti-vibration base made of a rubber-like elastic body interposed between the first fixture and the second fixture;
A main liquid chamber in which a liquid in which the vibration isolating substrate forms a part of a chamber wall is enclosed;
At least one sub-liquid chamber in which a liquid in which a diaphragm made of a rubber-like elastic film forms part of the chamber wall is enclosed;
A first orifice channel connecting the main liquid chamber and any one of the sub liquid chambers;
In a liquid-filled vibration isolator equipped with
An elastic membrane made of a rubber-like elastic body that partitions the sub-liquid chamber and the main liquid chamber, and the sub-liquid chamber and the main liquid chamber are connected to a partition that partitions the main liquid chamber and any sub-liquid chamber. And a second orifice channel tuned to a higher frequency range than the first orifice channel, and a second elastic channel formed of a rubber-like elastic film at the opening of the second orifice channel toward the sub liquid chamber side. A diaphragm is provided,
The second diaphragm is held in contact with the peripheral edge of the opening so that the outer peripheral portion is liquid-tight with respect to the partition body and the opening is closed by a flexible film portion inside the outer peripheral portion. A liquid-filled type vibration damping device, wherein the flexible film portion is provided with a through hole at a position that does not overlap the opening.   An opposing wall is provided on the secondary liquid chamber side of the second diaphragm so as to face the film surface of the flexible film portion on the side of the secondary liquid chamber with a space therebetween, and the flexible film portion includes the partition wall. 2. The liquid-filled vibration isolating device according to claim 1, wherein a projection that is compressed between the opposing wall is provided on a film surface on the side of the secondary liquid chamber at a position that does not overlap the opening of the body. apparatus.   An annular protrusion is provided on the peripheral part of the opening of the partition or the film surface on the main liquid chamber side of the flexible film part facing the peripheral part so as to surround the opening. Item 3. A liquid-sealed vibration isolator according to item 1 or 2.   The second diaphragm is arranged such that the flexible membrane part is separated from the opening of the second orifice channel toward the sub liquid chamber when the flow rate of the second orifice channel exceeds a predetermined amount. 4. The structure according to claim 1, wherein the liquid is bent and deformed, whereby the liquid is supplied from the through hole provided in the flexible film portion to the sub liquid chamber side. 5. Liquid-filled vibration isolator.   5. The flexible film portion according to claim 1, wherein the flexible membrane portion has a central portion in the radial direction as a plug portion that closes the opening, and has one or more through holes in a radially outward direction of the plug portion. The liquid-filled vibration isolator according to claim 1.   The flexible membrane portion has a radially central portion as a plug portion that closes the opening, the through holes are juxtaposed at a plurality of locations on the circumference surrounding the plug portion, and the protrusions are on the circumference. 3. The liquid filled type vibration damping device according to claim 2, wherein the liquid filled type vibration damping device is provided alternately with the through holes at a plurality of locations.   The sub liquid chamber connected to the main liquid chamber by the second orifice channel is a sub liquid chamber in which a diaphragm forming a partition wall with an air chamber or outside air forms a part of a chamber wall. The liquid-filled vibration isolator according to any one of claims 1 to 6.   The first fixture has a cylindrical shape, and the second fixture is arranged at the axial center of the first fixture, while the first fixture is attached to the first fixture and inside the first fixture. A first diaphragm made of a rubber-like elastic film forming a liquid sealing chamber is provided between the vibration isolating substrate, and the partition member defines the liquid sealing chamber as a main liquid chamber on the vibration isolating substrate side and the first diaphragm. Partitioning into a secondary liquid chamber on the side, the first orifice channel is provided in the outer peripheral portion of the partition body to connect the main liquid chamber and the secondary liquid chamber, and the elastic membrane is a partition body inside the outer peripheral portion. The main liquid chamber and the sub liquid chamber are partitioned in the portion, and the second orifice channel is provided by connecting the main liquid chamber and the sub liquid chamber in the partition portion inside the outer peripheral portion. The liquid-filled vibration isolator according to any one of claims 1 to 6.

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