JP5118454B2 - Liquid-filled vibration isolator - Google Patents

Description

  The present invention relates to a liquid-filled vibration isolator, and more particularly, to a liquid-filled vibration isolator capable of suppressing the occurrence of cavitation at the time of large amplitude vibration input while ensuring high damping characteristics at the time of normal amplitude vibration input. It is.

  2. Description of the Related Art A liquid-filled vibration isolator is known as a vibration isolator that prevents an engine vibration from being transmitted to a vehicle body frame while supporting and fixing an automobile engine.

  In the liquid-filled vibration isolator, generally, a first attachment attached to the engine side and a second attachment attached to the body frame side are connected by a vibration isolation base made of a rubber-like elastic body. A liquid sealing chamber is formed between the diaphragm attached to the fixture and the vibration-proof base. The liquid sealing chamber is partitioned into a main liquid chamber and a sub liquid chamber by a partition body, and the main liquid chamber and the sub liquid chamber are communicated with each other by an orifice.

  According to this liquid-filled vibration isolator, the vibration damping function and the vibration insulating function can be achieved by the liquid flow effect between the main liquid chamber and the sub liquid chamber by the orifice and the vibration damping effect of the vibration isolating substrate.

  By the way, in such a liquid filled type vibration isolator, cavitation may occur when a large amplitude vibration is input. Cavitation is performed when the first fixture and the second fixture are relatively displaced in a direction away from each other due to a large amplitude vibration input, and the pressure in the main liquid chamber becomes lower than the saturated vapor pressure. This is a phenomenon in which dissolved gas is liberated and bubbles are generated, and an impact is generated when the bubbles are crushed, which causes abnormal noise and vibration.

  Thus, a technique for suppressing the occurrence of cavitation when a large amplitude vibration is input has been proposed. For example, in Japanese Patent Laid-Open No. 8-170683, the second mounting bracket 5 that forms the air chamber 9 between the diaphragm 5 and the outer periphery of the cylindrical bracket 3 is assembled by press-fitting, and the second mounting bracket 5 is press-fitted. Accordingly, a technique for increasing the internal pressure of the air chamber 9 is disclosed.

According to this technique, since the liquid in the liquid enclosure 8 can be increased in pressure through the internal pressure of the air chamber 9 and the deformation of the diaphragm 5, the occurrence of cavitation when a large amplitude vibration is input can be suppressed. (Patent Document 1).
JP-A-8-170683

  However, since the above-described conventional technique is configured to increase the internal pressure of the air chamber, the expansion spring constant of the diaphragm is always high, which causes resistance to liquid flow. Therefore, in the normal amplitude vibration input region, it is difficult to obtain a liquid flow effect between the main liquid chamber and the sub liquid chamber by the orifice, and there is a problem that sufficient damping performance cannot be secured.

  The present invention has been made to solve the above-described problems, and is a liquid-filled type anti-corrosion that can suppress the occurrence of cavitation at the time of large amplitude vibration input while ensuring a high damping characteristic at the time of vibration input at a normal amplitude. The object is to provide a vibration device.

In order to achieve this object, the liquid-filled vibration isolator according to claim 1 connects the first fixture, the cylindrical second fixture, the second fixture, and the first fixture. And a vibration isolating base composed of a rubber-like elastic body, a diaphragm which is attached to the second fixture and forms a liquid sealing chamber between the vibration isolating base, and the liquid sealing chamber on the side of the vibration isolating base Partitioning means for partitioning the main liquid chamber and the sub-liquid chamber on the diaphragm side, and an orifice for allowing the main liquid chamber and the sub-liquid chamber to communicate with each other. A mounting portion that is annularly configured and is attached to the second fixture; an annular portion that is disposed in a central opening of the mounting portion and is configured from a metal material or a resin material in a circular shape when viewed from above; and the ring Part and mounting part And a flexible portion formed into a film shape from a rubber-like elastic body, the flexible portion connecting the inner peripheral side of the mounting portion and the outer peripheral side of the annular portion, An outer peripheral membrane portion for closing between the attachment portion and the annular portion; and a central membrane portion for closing a central opening of the annular portion, wherein the diaphragm is configured in a symmetrical shape around the axis, and the axis The cross section of the diaphragm includes a circular arc shape in which a central membrane portion of the flexible portion protrudes in a direction approaching the partitioning means in a non-acting state of hydraulic pressure, and the flexible portion The outer peripheral membrane portion is formed in an arc shape that is convex toward the opposite side of the central membrane portion, and the annular portion extends in a direction perpendicular to the axis, and the inner peripheral side of the attachment portion The distance between the outer peripheral membrane part between the outer peripheral side of the ring part and the annular part is perpendicular to the axis of the diaphragm In the middle membrane portion is set smaller than the inner diameter of, if the input displacement of large amplitude is inputted with a sine wave changing the direction alternately in the tensile direction and a compression direction, the response waveform of the pressure in the main liquid chamber Becomes a waveform different from the input waveform, and the width of the response waveform when the pressure in the main liquid chamber becomes negative is narrower than the response waveform when the pressure in the main liquid chamber becomes positive.

Hydraulic antivibration device according to claim 2, wherein, in the hydraulic antivibration device according to claim 1, wherein, prior Kienwa part, to the inner diameter of the mounting portion, the outer diameter dimension less than 1/2 And the inner diameter dimension is set to 1/3 or more.

Hydraulic antivibration device 請 Motomeko 3 wherein, in the liquid-filled vibration damping device according to claim 1 or 2, wherein the annular portion has its end portion is bent toward the outer peripheral layer portion It is configured in shape.

  According to the liquid-filled vibration isolator of claim 1, the diaphragm is formed from a metal material in an annular shape in a top view and is attached to the second fixture, and is disposed in the central opening of the fixture. In addition, a ring-shaped portion made of a metal material or a resin material in a circular shape when viewed from above is connected with a peripheral film portion formed in a film shape from a rubber-like elastic body, and the central opening of the ring-shaped portion is formed in a rubber shape A structure in which the elastic membrane is closed by a central membrane portion (that is, a rubber-like elastic body that is formed into a film shape is integrated with an annular portion that is formed into an annular shape from a metal material or a resin material) When the diaphragm is greatly expanded, the expansion (deformation) of the flexible portion (the outer peripheral membrane portion and the central membrane portion) is hindered by the rigidity of the annular portion, and the diaphragm expansion spring The constant can be increased.

  As a result, when a large-amplitude input displacement is input as a sinusoidal waveform that alternates between the compression direction and the tension direction, the pressure response waveform in the main liquid chamber is different from the input waveform. The response waveform when the pressure becomes negative is narrower in the time axis direction than the response waveform when the pressure becomes positive (suppresses the decrease when the pressure drops and accelerates the rise when the pressure rises Therefore, when a large amplitude vibration is input, the pressure drop in the main liquid chamber can be suppressed and the occurrence of cavitation can be suppressed.

  On the other hand, when the diaphragm is configured as described above, when the diaphragm is expanded in a vibration input region having a normal amplitude, the annular portion itself elastically supported by the central membrane portion and the outer peripheral membrane portion is the central membrane portion and the outer peripheral portion. By displacing together with the film part, it is possible to ensure the deformation of the flexible part (outer peripheral film part, central film part) as a whole and keep its rigidity low. As a result, the expansion spring constant of the diaphragm can be lowered to prevent the diaphragm from becoming a resistance to the liquid flow. Therefore, in the normal amplitude vibration input region, between the main liquid chamber and the sub liquid chamber by the orifice. The liquid flow effect is effectively exhibited, and the damping performance can be sufficiently secured.

Note that the amplitude dependency of the expansion spring constant of such a diaphragm cannot be imparted by a conventional diaphragm structure (consisting only of a rubber-like elastic body). Can be applied for the first time by embedding it in a flexible part, thereby simultaneously achieving the suppression of cavitation when large amplitude vibration is input and the improvement of damping characteristics when normal amplitude vibration is input. Can do.
In addition, the cross-sectional shape of the diaphragm including the shaft center is configured in an arc shape in which the central membrane portion is convex toward the direction approaching the partitioning means in the non-acting state of the hydraulic pressure, and the outer peripheral membrane portion is the central membrane. Since it is configured to have an arc shape that protrudes toward the opposite side of the part and the annular part extends in a direction perpendicular to the axis, the amplitude dependence of the expansion spring constant of the diaphragm is more pronounced Thus, there is an effect that it is possible to further achieve both the securing of the damping characteristic in the normal amplitude vibration input region and the suppression of the occurrence of cavitation when the large amplitude vibration is input.
Here, in the state where the vibration isolator is attached to the vehicle, the weight of the support body such as the engine is input to the vibration isolator as a shared load. As the distance is reduced and the volume of the main liquid chamber is decreased, the volume of the sub liquid chamber is increased. Therefore, the diaphragm is in an expanded state even when the vibration is not input compared to the state before the shared load is input (non-hydraulic action state).
In this case, according to the present invention, since the central membrane portion is formed in an arc shape that protrudes in the direction approaching the partitioning means, the expansion of the diaphragm with respect to the input of the shared load described above is mainly performed in the center. This is carried out by reversing or deforming the vicinity of the center of the film part or the entire film (turning over so that the convex direction is reversed), and the rigidity of the central film part can be kept low. At the same time, the central film portion is mainly deformed, so that the rigidity of the outer peripheral film portion can be kept low.
Therefore, even when the annular portion is integrally formed with the flexible portion as in the present invention, when the diaphragm is expanded in the vibration input region of the normal amplitude, the deformation of the central membrane portion itself and the center It is possible to ensure deformation of the flexible portion (outer peripheral membrane portion, central membrane portion) as a whole by displacing the annular portion itself elastically supported by the membrane portion and the outer peripheral membrane portion together with the central membrane portion and the outer peripheral membrane portion. it can. As a result, the expansion spring constant of the diaphragm can be lowered to prevent the diaphragm from becoming a resistance to the liquid flow. Therefore, in the normal amplitude vibration input region, between the main liquid chamber and the sub liquid chamber by the orifice. The liquid flow effect is effectively exhibited, and the damping performance can be sufficiently secured.
On the other hand, according to the present invention, the outer peripheral membrane portion is configured in an arc shape that is convex toward the opposite side to the central membrane portion, and the annular portion is configured to extend in a direction perpendicular to the axis. Therefore, when the diaphragm is greatly expanded, the expansion spring constant of the diaphragm is effectively increased by making the annular portion more effectively exhibit the function of inhibiting the expansion (deformation) of the flexible portion (outer peripheral membrane portion). Can be made. Thereby, at the time of large amplitude vibration input, there is an effect that the pressure drop in the main liquid chamber can be suppressed and the occurrence of cavitation can be suppressed.
Further, the distance between the outer peripheral film portion between the inner peripheral side of the attachment portion and the outer peripheral side of the annular portion is smaller than the inner diameter dimension of the central membrane portion in the direction orthogonal to the axis of the diaphragm. Therefore, the distance between the inner peripheral side of the mounting part and the outer peripheral side of the annular part, that is, the width dimension of the outer peripheral film part in the direction orthogonal to the axis of the diaphragm is made relatively narrow, and the inner diameter of the annular part The size, that is, the diameter of the central membrane portion that closes the central opening of the annular portion can be made relatively large. As a result, the expansion spring constant of the diaphragm has an amplitude dependency, so that it is possible to achieve both of ensuring damping characteristics in the normal amplitude vibration input region and suppressing the occurrence of cavitation at the time of large amplitude vibration input. There is.

  According to the liquid-filled vibration isolator according to claim 2, in addition to the effect exhibited by the liquid-filled vibration isolator according to claim 1, the outer diameter of the annular portion is ½ or more of the inner diameter of the mounting portion. And the inner diameter dimension of the annular portion is set to 1/3 or more of the inner diameter dimension of the mounting portion, and the width of the outer peripheral membrane portion connecting the outer peripheral side of the annular portion and the inner peripheral side of the mounting portion is relatively Since the center membrane part that closes the center opening of the ring part is made relatively narrow in diameter, the diaphragm's expansion spring constant has an amplitude dependence, and the damping characteristics in the normal vibration input region It is possible to achieve both the securing of the cavitation and the suppression of the occurrence of cavitation when a large amplitude vibration is input.

  For example, if the width of the outer peripheral membrane portion is made relatively wide and the diameter of the central membrane portion is made relatively small as opposed to the above configuration, the expansion spring constant of the diaphragm can have amplitude dependency. Therefore, it is impossible to achieve both the securing of the damping characteristics in the normal amplitude vibration input region and the suppression of the occurrence of cavitation when the large amplitude vibration is input.

  That is, if the outer diameter dimension of the annular part is set to be smaller than 1/2 of the inner diameter dimension of the attachment part, the width of the outer peripheral film part connecting the outer peripheral side of the annular part and the inner peripheral side of the attachment part is increased. Therefore, when the diaphragm is greatly expanded, the expansion (deformation) of the flexible portion (peripheral membrane portion) cannot be inhibited by the rigidity of the annular portion, and it becomes difficult to increase the expansion spring constant of the diaphragm. Thus, it is not possible to obtain a sufficient difference from the expansion spring constant when the diaphragm is expanded in a vibration input region having a normal amplitude. As a result, it is possible to ensure the attenuation characteristics in the normal amplitude vibration input region, but it is not possible to suppress the occurrence of cavitation when a large amplitude is input.

  Also, if the inner diameter dimension of the annular part (the diameter of the central opening) is set smaller than 1/3 of the inner diameter dimension of the mounting part, the diameter of the central membrane part (ie, the surface area) that closes the central opening of the annular part is sufficient. Therefore, even when the diaphragm is expanded in the vibration input region having the normal amplitude, the expansion spring constant of the diaphragm becomes too high. As a result, it is possible to suppress the occurrence of cavitation at the time of inputting a large amplitude, but it is not possible to secure the attenuation characteristic in the vibration input region of the normal amplitude.

  On the other hand, according to the present invention, the outer diameter and inner diameter of the annular part are configured as described above with respect to the inner diameter of the mounting part (that is, the width of the outer peripheral film part is relatively narrow and the central film part is When the diaphragm is greatly expanded by making the diameter of the diaphragm relatively large), the expansion (deformation) of the flexible part (outer peripheral film part) is hindered by the rigidity of the annular part, and the expansion spring constant of the diaphragm is reduced. It can be increased effectively. On the other hand, when the diaphragm is expanded in a vibration input region having a normal amplitude, the deformation of the central membrane portion itself and the annular portion elastically supported by the central membrane portion and the outer peripheral membrane portion together with the central membrane portion and the outer peripheral membrane portion The expansion spring constant of the diaphragm can be lowered by securing the deformation of the flexible portion (outer peripheral membrane portion, central membrane portion) as a whole by maintaining the low rigidity.

  As a result, the diaphragm can have an amplitude dependency, so that when a large amplitude vibration is input, the pressure drop in the main liquid chamber can be suppressed, the occurrence of cavitation can be suppressed, and the normal amplitude vibration can be suppressed. In the input region, there is an effect that the liquid flow effect between the main liquid chamber and the sub liquid chamber by the orifice can be efficiently exhibited, and the damping performance can be sufficiently ensured.

According to the hydraulic antivibration device 請 Motomeko 3, wherein in addition to the effects of the hydraulic antivibration device according to claim 1 or 2, wherein the annular portion has its end toward the circumferential membrane unit Because it is configured in a bent shape, when greatly expanding the diaphragm, not only the rigidity of the annular part, but also the effect of the overlap between the outer peripheral membrane part and the annular part and the shape of the annular part are bent. Due to this effect, the expansion (deformation) of the outer peripheral film portion can be effectively inhibited, and the expansion spring constant of the diaphragm can be effectively increased. As a result, there is an effect that the occurrence of cavitation can be more reliably suppressed when a large amplitude vibration is input.

  DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, preferred embodiments of the invention will be described with reference to the accompanying drawings. FIG. 1 is a cross-sectional view of a liquid-filled vibration isolator 100 according to an embodiment of the present invention.

  The liquid-filled vibration isolator 100 is a vibration isolator for supporting and fixing an automobile engine so that the engine vibration is not transmitted to the vehicle body frame, and is attached to the engine side as shown in FIG. A first mounting bracket 1, a cylindrical second mounting bracket 2 that is mounted on the vehicle body frame side below the engine, and a vibration-proof base 3 that is connected to the first mounting bracket 1 and is made of a rubber-like elastic body.

  The first mounting bracket 1 is formed in a substantially cylindrical shape from a metal material such as an aluminum alloy, and as shown in FIG. 1, the upper end surface (upper side surface in FIG. 1) is fastened with a mounting bolt on the engine side. The hole 1a is recessed, and a positioning protrusion 1b is formed on the side of the fastening hole 1a. Further, a substantially flange-shaped protruding portion is formed on the outer peripheral portion of the first mounting portion 1, and the protruding portion abuts against the stabilizer fitting 9 so that a stopper action at the time of large displacement can be obtained. Has been.

  As shown in FIG. 1, the second mounting bracket 2 includes a cylindrical bracket 4 on which the vibration-proof base 3 is vulcanized and a bottom bracket 5 attached below the cylindrical bracket 4. Has been. The cylindrical metal fitting 4 is formed in a cylindrical shape having an opening that spreads upward, and the bottom metal fitting 5 is formed in a cup shape having a bottom portion, respectively, from a steel material or the like. Two mounting bolts 6 project from the bottom of the bottom metal fitting 5.

  As shown in FIG. 1, the anti-vibration base 3 is formed in a truncated cone shape from a rubber-like elastic body, and is vulcanized and bonded between the lower surface side of the first mounting bracket 1 and the upper end opening of the cylindrical bracket 4. ing. Further, a rubber film 3a covering the inner peripheral surface of the cylindrical metal fitting 4 is connected to the lower end portion of the vibration isolating base 3. The rubber film 3a is in close contact with the outer peripheral side of a partition metal fitting 20 which will be described later. Is formed.

  As shown in FIG. 1, the diaphragm 30 includes a flexible part 31 formed from a rubber-like elastic body in the form of a rubber film having a partial spherical shape, and vulcanized and molded integrally with the flexible part 31 and from a metal material. An attachment portion 32 and an annular portion 33 configured in an annular shape when viewed from above are provided. As shown in FIG. 1, the attachment portion 32 is caulked and fixed between the cylindrical fitting 4 and the bottom fitting 5 together with the partition fitting 20. Thus, the second mounting bracket 2 is attached. As a result, a liquid sealing chamber 11 is formed between the diaphragm 30 and the lower surface of the vibration isolating substrate 3.

  In the liquid enclosure 11, an antifreeze liquid (not shown) (in this embodiment, an ethylene glycol aqueous solution having a weight ratio of ethylene glycol to water of 7: 3. Note that saturated vapor at room temperature (25 ° C.). The pressure is 0.1 MPa). Further, the liquid sealing chamber 8 is divided into two chambers, a main liquid chamber 11A on the vibration isolating base 3 side and a sub liquid chamber 11B on the diaphragm 9 side, by a partition metal 20 which will be described later.

  As shown in FIG. 1, the partition metal 20 is formed in a disk shape by pressing a metal plate, and an overhanging portion 21 projecting outward from the lower edge of the partition 20 together with the attachment portion 32 of the diaphragm 20 is cylindrical. The second mounting bracket 2 is attached by caulking and fixing between the bracket 4 and the bottom bracket 5.

  The partition metal fitting 20 is formed such that the central portion of the outer peripheral surface is recessed inward, and the space between the outer peripheral surface and the rubber film 3a covering the inner peripheral surface of the second mounting metal fitting 2 is shown in FIG. Thus, the orifice 25 is formed. The orifice 25 is an orifice channel for communicating the main liquid chamber 11A and the sub liquid chamber 11B and for allowing the liquid to flow between the two liquid chambers 11A and 11B, and is formed along the outer peripheral surface of the partition metal fitting 20. Has been.

  The orifice channel is divided (partitioned) by a vertical wall (not shown) formed on the outer peripheral surface of the partition member 20 and in close contact with the rubber film 3a. As shown in FIG. While communicating with the main liquid chamber 11 </ b> A through the opening 22, the other end communicates with the sub liquid chamber 11 </ b> B through the second opening 23.

  Next, the detailed configuration of the diaphragm 30 will be described with reference to FIGS. 2 to 5. 2A is a top view of the diaphragm 30, and FIG. 2B is a cross-sectional view of the diaphragm 30 taken along the line IIb-IIb in FIG. 2A.

  As described above, the diaphragm 30 is a member for forming the liquid sealing chamber 11 between the lower surface of the vibration isolating base 3 (see FIG. 1), and is configured such that the expansion spring constant has amplitude dependency. ing. The expansion spring constant means a force (pressure) required to expand the diaphragm 30 and change the volume of the sub liquid chamber 11B by a unit volume.

  As shown in FIGS. 2A and 2B, the diaphragm 30 includes a flexible portion 31, a mounting portion 32, and an annular portion 33, and has a disk shape symmetrical around the axis O. It is configured. As shown in FIGS. 2 (a) and 2 (b), the flexible portion 31 is a portion formed from a rubber-like elastic body into a rubber film shape having a partial spherical shape, and includes a peripheral film portion 31a and a parallel portion. 31b and the center membrane part 31c are mainly provided, and the attachment part 32 and the annular part 33 are integrally formed by vulcanization molding.

  Here, with reference to FIG.3 and FIG.4, the detailed structure of the attaching part 32 and the annular part 33 is demonstrated. 3A is a top view of the attachment portion 32, and FIG. 3B is a cross-sectional view of the attachment portion 32 taken along the line IIIb-IIIb in FIG. 3A.

  The attachment portion 32 is a member that is integrally molded (vulcanized) with the flexible portion 31 and the annular portion 33, and as shown in FIGS. 3 (a) and 3 (b), the attachment flat plate portion 32a The cylindrical portion 32b is formed in a symmetrical shape around the axis O from a metal material.

  The mounting flat plate portion 32a is a portion that is caulked and fixed between the cylindrical metal fitting 4 and the bottom metal fitting 5 (see FIG. 1), and is configured as a flat plate that is orthogonal to the axis O and is circular in top view. . The cylindrical portion 32b is a portion for reinforcing the mounting portion 32, is configured in a cylindrical shape extending in parallel around the axis O, and is connected to the inner peripheral side of the mounting flat plate portion 32a. The inner diameter of the attachment portion 32 (tubular portion 32b) is D1.

  Here, the attachment portion 32 is caulked and fixed between the cylindrical metal fitting 4 and the bottom metal fitting 5 on the outer peripheral edge side (see FIG. 1), while the flexible portion 31 (the outer peripheral film portion 31a) is provided on the inner peripheral edge side. The structure is connected (see FIG. 2 or FIG. 5), and at the time of inputting a large amplitude, a large bending deformation acts on the mounting flat plate portion 32a with the effect of increasing the film rigidity by the annular portion 33 described later.

  In this case, if the mounting plate portion 32a is bent and deformed, the expansion spring constant of the diaphragm 9 cannot be increased when a large amplitude vibration is input. Therefore, in the liquid filled type vibration damping device 100 according to the present embodiment, as described above, the cylindrical portion 32b is continuously provided on the inner peripheral side of the mounting flat plate portion 32a. In the case of large expansion, bending expansion of the attachment portion 32 (attachment flat plate portion 32a) can be suppressed, and the expansion spring constant of the diaphragm can be increased. As a result, it is possible to further suppress the occurrence of cavitation.

  4A is a top view of the annular portion 33, and FIG. 4B is a cross-sectional view of the annular portion 33 taken along line IVb-IVb in FIG. 4A. The annular portion 33 is a member that is integrally molded (vulcanized) with the flexible portion 31 and the attachment portion 33, and as shown in FIGS. 4A and 4B, the annular flat plate portion 33a. And an inclined portion 33b, and is formed in a symmetrical shape around the axis O from a metal material.

  The annular flat plate portion 33a is configured as a flat plate that is orthogonal to the axis O and is circular when viewed from above, and the inclined portion 33b is connected to the outer peripheral edge of the annular flat plate portion 33a and is connected to the axis O. It is formed so as to be inclined downward at an angle of approximately 45 degrees.

  As described above, the annular plate portion 33a and the inclined portion 33b are connected to each other with a predetermined inclination angle, so that the diaphragm 9 has a flexible portion 31 when a large amplitude vibration is input, as will be described later. The durability of the flexible portion 31 can be improved while the rigidity of the flexible portion 31 is increased.

  The connecting portion (connecting portion) between the annular flat plate portion 33a and the inclined portion 33b is curved in an arc shape. Further, the outer diameter of the annular portion 33 (inclined portion 33b) is D2, and the inner diameter of the annular portion 33 (annular flat plate portion 33a) is D3.

  Returning to FIG. As described above, the flexible part 31 mainly includes the outer peripheral film part 31a, the parallel part 31b, and the central film part 31c, and these parts 31a to 31c are symmetrical around the axis O from the rubber-like elastic body. It is formed in a film shape and is integrally formed with the mounting portion 32 and the annular portion 33 described above by vulcanization molding.

  As shown in FIGS. 2A and 2B, the outer peripheral film portion 31 a connects the inner peripheral side of the mounting portion 32 and the outer peripheral side of the annular portion 33, and connects the mounting portion 32 and the annular ring. This is a portion that closes the gap between the portion 33 and is curved in a convex arc shape toward the side opposite to the partition fitting 20 (see FIG. 1).

  As shown in FIGS. 2A and 2B, the parallel part 31 b is a part that covers the upper and lower surfaces (upper and lower surfaces in FIG. 2B) of the annular part 33, and It is formed in a film shape that is orthogonal to the upper surface and has an annular shape when viewed from above.

  As shown in FIGS. 2 (a) and 2 (b), the central membrane portion 31c is a member that closes the central opening (inner peripheral side) of the annular portion 33, and the sectional shape including the axis O is a partition fitting. It is curved in a convex arc shape toward the 20 (see FIG. 1) side. That is, the central film part 31c is formed in a convex arc shape in the direction opposite to the outer peripheral film part 31a.

  Thus, the cross-sectional shape of the diaphragm 30 including the axis O is such that the central membrane portion 31c approaches the partition fitting 20 (see FIG. 1) (upward in FIG. 2B) in a non-actuated state of hydraulic pressure. The outer peripheral film portion 31a is formed in an arc shape that protrudes toward the opposite side (downward in FIG. 2B) to the opposite side of the central film portion 31c, and the annular portion. Since the annular flat plate portion 33a has a configuration extending in the direction orthogonal to the axis O (the left-right direction in FIG. 2B), the expansion spring constant of the diaphragm 30 is more significantly exhibited in amplitude dependency. Thus, it is possible to further achieve both the securing of the damping characteristic in the normal amplitude vibration input region and the suppression of the occurrence of cavitation when the large amplitude vibration is input.

  Here, in the state in which the liquid filled type vibration isolator 100 (see FIG. 1) is attached to the vehicle, the weight of the supported body such as the engine is input as a shared load. The relative distance from the fixture 2 (tubular fitting 4) is shortened, and the volume of the sub liquid chamber 11B is increased as the volume of the main liquid chamber 11A is decreased. Therefore, the diaphragm 30 (flexible part 31) is in an expanded state even in a state where no vibration is input, compared to a state before the shared load is input (non-hydraulic action state).

  In this case, according to the present invention, the central membrane portion 31c is formed in an arc shape that protrudes in the direction approaching the partition member 20, so that the diaphragm 30 (flexible portion 31) with respect to the input of the shared load described above. ) Is mainly performed by reversing or deforming the center film portion 31c near or in the center (turning over so that the convex direction is opposite), and maintaining the rigidity of the center film portion 31c in a low state. be able to. At the same time, the central film portion 31c is mainly deformed, so that the rigidity of the outer peripheral film portion 31a can be kept low.

  Therefore, even when the annular portion 33 is integrally formed (embedded) in the flexible portion 31 as in the present invention, when the diaphragm 30 is expanded in a vibration input region having a normal amplitude, the central membrane portion The flexible part 31 (the outer peripheral film part 31a, the outer peripheral film part 31a, the outer peripheral film part 31a and the annular part 33 itself elastically supported by the deformation of the central film part 31c and the outer peripheral film part 31a are displaced. It is possible to ensure the deformation of the central film portion 31c) as a whole. Thereby, the expansion spring constant of the diaphragm 30 can be lowered and the diaphragm 30 can be prevented from becoming a resistance to liquid flow. Therefore, in the normal amplitude vibration input region, the main liquid chamber 11A and the auxiliary liquid by the orifice 25 can be avoided. The liquid flow effect between the chambers 11B can be efficiently exhibited (both refer to FIG. 1), and the damping performance can be sufficiently ensured.

  On the other hand, the outer peripheral film portion 31a is formed in an arc shape that is convex toward the opposite side to the central film portion 31c, and the annular portion 33 (flat plate annular portion 33a) extends in a direction orthogonal to the axis O. Therefore, when the diaphragm 30 is greatly expanded, the function of inhibiting the expansion (deformation) of the flexible portion 31 (the outer peripheral film portion 31c) by the annular portion 33 is more significantly exhibited. The expansion spring constant of 30 can be increased effectively. As a result, when a large amplitude vibration is input, the pressure drop in the main liquid chamber 11A (see FIG. 1) can be suppressed, and the occurrence of cavitation can be suppressed.

FIG. 5 is a partially enlarged cross-sectional view of the diaphragm 30 and corresponds to a partially enlarged view of a part of FIG. Note that FIG. 5 (and FIG. 2A) corresponds to the “cross section of the diaphragm including the axial center” described in claim 1 .

  As shown in FIG. 5, the diaphragm 30 is configured to have a symmetrical shape with respect to the axis O in a non-acting state of hydraulic pressure (that is, a single product state of the diaphragm 30 shown in FIG. 5). An annular portion 33 is disposed at the (central opening), and the mounting flat plate portion 32a and the annular flat plate portion 33a of both the portions 32 and 33 are both disposed perpendicular to the axis O.

  Further, as shown in FIG. 5, the outer peripheral film part 31a, the parallel part 31b, and the central film part 31c are all configured with the same film thickness (film thickness dimension t). The film thickness dimension t is preferably set to a value of 2% or more and 5% or less with respect to the inner diameter dimension D1 of the attachment portion 32.

  When the film thickness dimension t is smaller than 2% with respect to the inner diameter dimension D1, the flexible portion 31 is likely to be broken when a large amplitude vibration is input, leading to a decrease in durability, while the film thickness dimension t is 5 This is because if the value exceeds%, the rigidity of the flexible portion 31 becomes too high, and it becomes difficult to ensure the damping characteristics when a normal amplitude vibration is input. In the present embodiment, the film thickness dimension t is set to 3% with respect to the inner diameter dimension D1.

  As described above, the outer peripheral film portion 31a is formed in an arc shape that protrudes toward the side opposite to the central film portion 31c (that is, the side opposite to the partition metal fitting 20, the lower side in FIG. 5), and is shown in FIG. As described above, the radial dimension of the arc shape is set to the radius Ra. The radius Ra corresponds to the radial dimension at the center in the thickness direction of the outer peripheral film portion 31a. That is, the diameter dimension on the inner circumference side (upper side in FIG. 5) of the arc shape is smaller than the radius Ra by half the film thickness dimension t, and the diameter dimension on the outer circumference side (lower side in FIG. 5) is half the film thickness dimension t. Only get bigger.

  Here, in the arc shape of the outer peripheral film portion 31a, the radius Ra corresponds to the separation dimension between the inner peripheral side of the attachment portion 32 and the outer peripheral side of the annular portion 33 (that is, (D1-D2) / 2). As shown in FIG. 5, the center of the arc shape coincides with the lower end (lower end in FIG. 5) of the annular portion 33 (inclined portion 33 b). Are arranged.

  As described above, the diaphragm 30 is expanded in the vibration input region of the normal amplitude by configuring the outer peripheral film portion 31a with only the arc shape in the cross-sectional shape including the axis O (that is, the shape not including the linear portion). In this case, it is possible to easily displace the annular portion 33 itself in the vertical direction (the vertical direction in FIG. 5) together with the deformation of the outer peripheral film portion 31a (deformation that extends the arc shape linearly), and keep its rigidity low. The expansion spring constant of the diaphragm 30 can be lowered. On the other hand, when the diaphragm 30 is greatly expanded, the expansion (constant) of the flexible portion 31 (the outer peripheral film portion 31a) is easily inhibited by the rigidity of the annular portion 33, and the expansion spring constant of the diaphragm 30 is effectively increased. Can be increased.

  As a result, the diaphragm 30 can have amplitude dependency, and therefore, when a large amplitude vibration is input, the pressure drop in the main liquid chamber 11A (see FIG. 1) is suppressed, thereby suppressing the occurrence of cavitation. In addition, the liquid flow effect between the main liquid chamber 11A and the sub liquid chamber 11B by the orifice 25 can be efficiently exhibited in the normal amplitude vibration input region (both refer to FIG. 1), and the damping performance is sufficient. Can be secured.

  As described above, the parallel portion 31b is a portion that covers the upper and lower surfaces (upper and lower surfaces in FIG. 5) of the annular portion 33, and extends in a direction perpendicular to the axis O as shown in FIG. In addition, the both ends are curved in an arc shape and are smoothly connected to the outer peripheral film portion 31a and the central film portion 31c.

  Here, as shown in FIG. 5, the annular portion 33 is connected in a state where the annular flat plate portion 33 a and the inclined portion 33 b form a predetermined angle (45 degrees), and the outer peripheral side (right side in FIG. 5). The end portion (inclined portion 33b) is embedded in the parallel portion 31b at a position overlapping the outer peripheral film portion 31a when viewed in the direction of the axis O.

  That is, as shown in FIG. 5, the annular portion 33 is configured such that the inclined portion 33 b is inclined downward from the annular flat plate portion 33 a toward the outer peripheral film portion 31 a (configured in a shape in which the annular portion 33 is bent). The annular flat plate portion 33a is embedded in the parallel portion 31b, and a part of the inclined portion 33b is embedded in a part of the outer peripheral film portion 31a.

  Thereby, when the diaphragm 30 is greatly expanded, not only the rigidity of the annular portion 33 but also the effect of overlapping the outer peripheral membrane portion 31a and the annular portion 33 and the effect of bending the shape of the annular portion 33 are obtained. The expansion (constant) of the outer peripheral film portion 31a can be effectively inhibited, and the expansion spring constant of the diaphragm 30 can be effectively increased. As a result, the occurrence of cavitation can be more reliably suppressed when a large amplitude vibration is input.

  On the other hand, as shown in FIG. 5, the annular portion 33 is located at a position where the end portion (annular flat plate portion 33 a) on the inner peripheral side (left side in FIG. 5) does not overlap with the central film portion 31 c when viewed in the axial center O direction. It is embedded in the parallel part 31b, and a gap is formed between the inner peripheral end part and the central film part 31c. That is, the parallel portion 31b includes a non-embedded portion that is formed only of a rubber-like elastic body without the annular portion 33 being embedded in the connection portion side with the central film portion 31c.

  As a result, when the diaphragm 30 is expanded in a vibration input region having a normal amplitude, the expansion (displacement) of the central film portion 31c is prevented from being hindered by the rigidity of the annular portion 33, and the central film portion 31c Since the deformation can be ensured (the rigidity is kept low), the expansion spring constant of the diaphragm 30 can be lowered. As a result, in the vibration input region of the normal amplitude, the liquid flow effect between the main liquid chamber 11A and the sub liquid chamber 11B by the orifice 25 is efficiently exhibited (both see FIG. 1), and sufficient damping performance is ensured. can do.

  In addition, as described above, the diaphragm 30 is configured such that the inclined portion 33b is inclined downward at a predetermined angle (45 °) with respect to the annular flat plate portion 33a, and the annular portion 33 is formed into the shape of the parallel portion 31b and the outer peripheral film portion 31a. When the diaphragm 30 is greatly expanded and the annular portion 33 is displaced downward (on the opposite side to the partition metal fitting 20 and the lower side in FIG. 5) together with the central membrane portion 31c. Further, it is possible to reduce the burden on the outer peripheral film part 31a and the connection part between the outer peripheral film part 31a and the parallel part 31b. As a result, damage such as film breakage of the outer peripheral film portion 31a and the parallel portion 31b can be suppressed, and the durability of the diaphragm 30 can be improved accordingly.

  As described above, the central membrane portion 31c is formed in an arc shape that protrudes toward the partition metal fitting 20 (see FIG. 1), and as shown in FIG. 5, the arc dimension has a radius Rc. Is set to The radius Rc corresponds to the radial dimension at the center in the thickness direction of the central film portion 31c. That is, the diameter dimension on the outer peripheral side (upper side in FIG. 5) of the arc shape is larger than the radius Rc by half the film thickness dimension t, and the diameter dimension on the inner peripheral side (lower side in FIG. 5) is half the film thickness dimension t. Only smaller.

  Here, the center film portion 31c has an arc-shaped radius Rc set within a range of 55% or more and 75% or less with respect to the inner diameter D3 of the annular portion 33, and as shown in FIG. It is preferable that it is composed of only an arc shape (that is, a shape that does not include a linear portion).

  If the radius Rc is larger than 75% of the inner diameter dimension D3, the film length (length along the arc) becomes shorter and the reversal effect at the time of shared load action becomes weaker. When expanding in the vibration input region of amplitude, it becomes difficult to keep the rigidity of the central membrane portion 31c low, and the expansion spring constant of the diaphragm 30 cannot be lowered, while the radius Rc is 55% of the inner diameter D3. If it is smaller, the film length (length along the arc) becomes longer. Therefore, when the diaphragm 30 is greatly expanded, the deformation of the central film part 31c is increased, and the rigidity of the flexible part 31 as a whole is reduced. This is because the expansion spring constant of the diaphragm 30 cannot be increased effectively.

  In the present embodiment, the radius Rc is set to 65% of the inner diameter dimension D3. As a result, when the diaphragm 30 is expanded in a vibration input region having a normal amplitude, the rigidity of the central membrane portion 31c can be kept low, the expansion spring constant of the diaphragm 30 can be lowered, and the diaphragm 30 can be greatly expanded. In this case, the deformation of the central membrane portion 31c can be suppressed, and the expansion spring constant of the diaphragm 30 can be effectively increased.

  As a result, the diaphragm 30 can have amplitude dependency, and therefore, when a large amplitude vibration is input, the pressure drop in the main liquid chamber 11A (see FIG. 1) is suppressed, thereby suppressing the occurrence of cavitation. In addition, the liquid flow effect between the main liquid chamber 11A and the sub liquid chamber 11B by the orifice 25 can be efficiently exhibited in the normal amplitude vibration input region (both refer to FIG. 1), and the damping performance is sufficient. Can be secured.

  Here, in the present embodiment, the outer diameter D2 of the annular portion 33 is set to 80% of the inner diameter D1 of the mounting portion 33 (D2 = 0.8 × D1), and the inner diameter of the annular portion 33 is set. The dimension D3 is set to 60% of the inner diameter dimension D1 of the mounting portion 32 (D3 = 0.6 × D1).

  Thereby, the interval between the inner peripheral side of the mounting portion 32 and the outer peripheral side of the annular portion 33 (that is, the width dimension of the outer peripheral film portion 31a in the direction perpendicular to the axis O, the horizontal dimension in FIG. 5). While being relatively narrow, the inner diameter dimension D3 of the annular portion 33 (that is, the diameter of the central membrane portion 31c that closes the central opening of the annular portion 33, the lateral dimension in FIG. 5) can be made relatively large.

  As a result, the expansion spring constant of the diaphragm 30 has an amplitude dependency, so that it is possible to ensure both the damping characteristics in the normal amplitude vibration input region and the suppression of the occurrence of cavitation when a large amplitude vibration is input.

  For example, contrary to the present embodiment, the width dimension (dimension in the left-right direction in FIG. 5) of the outer peripheral film portion 31a is relatively wide (for example, the outer diameter dimension D2 of the annular portion 33 is equal to the inner diameter dimension D1 of the mounting portion 32). Smaller than 1/2), and the diameter (dimension in the left-right direction in FIG. 5) of the central film portion 31c is relatively small (for example, the inner diameter D3 of the annular portion 33 is smaller than 1/3 of the inner diameter D1 of the mounting portion 32). If the configuration is small, the expansion spring constant of the diaphragm 30 cannot have an amplitude dependency, and it is possible to secure a damping characteristic in a normal amplitude vibration input region and to suppress generation of cavitation when a large amplitude vibration is input. Cannot be achieved.

  That is, if the outer peripheral film part 31a connecting the outer peripheral side of the annular part 33 and the inner peripheral side of the attachment part 32 becomes too wide, the flexible part 31 (the outer peripheral film part) The expansion (deformation) of 31a) cannot be inhibited by the rigidity of the annular portion 33, and it becomes difficult to increase the expansion spring constant of the diaphragm 30, and when the diaphragm 30 is expanded in a vibration input region of a normal amplitude. A sufficient difference from the expansion spring constant cannot be obtained. As a result, it is possible to ensure the attenuation characteristics in the normal amplitude vibration input region, but it is not possible to suppress the occurrence of cavitation when a large amplitude is input.

  Further, when the diameter (that is, the surface area) of the central membrane portion 31c that closes the central opening of the annular portion 33 is not sufficiently ensured, the expansion of the diaphragm 30 is possible even when the diaphragm 30 is expanded in a vibration input region having a normal amplitude. The spring constant is too high. As a result, it is possible to suppress the occurrence of cavitation at the time of inputting a large amplitude, but it is not possible to secure the attenuation characteristic in the vibration input region of the normal amplitude.

  On the other hand, as in the present invention, the width dimension (lateral dimension in FIG. 5) of the outer peripheral film portion 31a is relatively narrow (preferably, the outer diameter dimension D2 of the annular portion 33 is set to the inner diameter dimension D1 of the mounting portion 32. And the central membrane portion 31c has a relatively large diameter (dimension in the left-right direction in FIG. 5) (preferably, the inner diameter D3 of the annular portion 33 is set to 1 / of the inner diameter D1 of the mounting portion 32). 3), when the diaphragm 30 is greatly expanded, the expansion (deformation) of the flexible portion 31 (the outer peripheral film portion 31a) is inhibited by the rigidity of the annular portion 33, and the diaphragm 30 is The expansion spring constant can be effectively increased.

  On the other hand, when the diaphragm 30 is expanded in a vibration input region having a normal amplitude, the deformation of the central membrane portion 31c itself and the annular portion 33 itself elastically supported by the central membrane portion 31c and the outer peripheral membrane portion 31a are connected to the central membrane portion. Displacement together with 31c and the outer peripheral film part 31a ensures the deformation of the flexible part 31 (the outer peripheral film part 31a and the central film part 31c) as a whole and keeps its rigidity low, thereby expanding the diaphragm 30. The spring constant can be lowered.

  As a result, the diaphragm 30 can have amplitude dependency, and therefore, when a large amplitude vibration is input, the pressure drop in the main liquid chamber 11A (see FIG. 1) is suppressed, thereby suppressing the occurrence of cavitation. In addition, the liquid flow effect between the main liquid chamber 11A and the sub liquid chamber 11B by the orifice 25 can be efficiently exhibited in the normal amplitude vibration input region (both refer to FIG. 1), and the damping performance is sufficient. Can be secured.

  In addition, it is preferable that the width dimension (dimension in the left-right direction in FIG. 5) of the outer peripheral film portion 31a is at least twice the film thickness dimension t to ensure a certain width dimension. That is, it is preferable that the outer diameter D2 of the annular portion 33 is smaller than the value obtained by subtracting four times the film thickness pressure t from the inner diameter D1 of the mounting portion 32 (D2 <D1-4t).

  If the width dimension of the outer peripheral film portion 31a is made too narrow, it becomes necessary to increase the radius Ra of the outer peripheral film portion 31a (that is, close to a linear shape), and the annular portion 33 is displaced at the time of normal vibration input. It becomes difficult. For this reason, the rigidity of the entire flexible portion 31 is increased, and the expansion spring constant is increased, which results in a decrease in damping characteristics when a normal amplitude vibration is input.

  On the other hand, as in the present invention, by setting the width dimension (dimension in the left-right direction in FIG. 5) of the outer peripheral film portion 31a to be twice or more the film thickness dimension t, the outer peripheral film portion 31a is curved into a relatively small arc shape. Therefore, the effect of displacing the annular portion 33 can be reliably exhibited by the deformation of the outer peripheral film portion 31a curved in an arc shape. Therefore, since the rigidity of the flexible portion 31 as a whole can be kept low and the expansion spring constant can be lowered, it is possible to improve the damping characteristics when a normal amplitude vibration is input.

  Further, the inner diameter dimension D3 of the annular portion 33 is preferably set so that the width dimension (the lateral dimension in FIG. 5) of the annular portion 33 is three times or more the film thickness dimension t. That is, it is preferable that the difference between the outer diameter dimension D2 and the inner diameter dimension D3 of the annular portion 33 is not less than six times the film thickness dimension t (D3 <D2-6t). If the width dimension of the annular part 33 is too narrow, it becomes difficult to inhibit the expansion (deformation) of the outer peripheral film part 31a due to the rigidity of the annular part 33, and the area ratio occupied by the central film part 31c becomes too large. This is because the expansion spring constant of the diaphragm 30 cannot be increased, and cavitation occurs when a large amplitude vibration is input.

  Next, with reference to FIG. 6 and FIG. 7, a characteristic evaluation result of the liquid filled type vibration damping device 100 will be described. FIG. 6 is a graph showing the expansion spring constant of the diaphragm 30. In FIG. 6, the horizontal axis represents the input amount h to the liquid-filled vibration isolator 100, and the vertical axis represents the expansion spring constant K of the diaphragm 30.

  Further, the “invention product” indicated by a square in FIG. 6 corresponds to the liquid-filled vibration isolator 100 including the diaphragm 30 described above, and the “conventional product” indicated by a triangle in FIG. 6 corresponds to the diaphragm 30 described above. On the other hand, it corresponds to a liquid-filled vibration isolator provided with a diaphragm in which the annular portion 33 is omitted. That is, the difference between the “invention product” and the “conventional product” is only the presence or absence of the annular portion 33, and the other configurations are the same.

  The input amount h corresponds to the input amount from the shared load load state in which the weight of the support body such as the engine is input to the liquid-filled vibration isolator 100 as the shared load. That is, the position where the horizontal axis intersects the vertical axis (input amount h = 0 mm) is the shared load loading state.

  Therefore, for example, in FIG. 6, the expansion spring constant K at an input amount h = 2 mm is input with a compression displacement from a shared load load state, and the first mounting bracket 1 and the second mounting bracket 2 (tubular bracket 4) Is the expansion spring constant of the diaphragm 30 in the expanded state as the volume of the main liquid chamber 11A decreases and the volume of the sub liquid chamber 11B increases.

  As shown in FIG. 6, in the “conventional product”, the change in the expansion spring constant K with respect to the increase in the input amount h is small, and the change does not change even if the input amount h increases. It tends to decrease slightly.

  On the other hand, the “invention product” corresponds to the increase in the input amount h in the range corresponding to the amplitude of the vibration input region having the normal amplitude (that is, the input amount h is in the range of about 0 mm to 1 mm), like the “conventional product”. The change of the expansion spring constant K is small, and even if the input amount h increases, the expansion spring constant K tends to be almost flat. Also, the value of the expansion spring constant K is not significantly different from the conventional product.

  However, in the “invention product”, the expansion spring constant K tends to increase greatly as the input amount h increases in a range corresponding to a large amplitude vibration input (that is, a range where the input amount h exceeds 1 mm). That is, in the “invention product”, the expansion spring constant K of the diaphragm 30 can have an amplitude dependency.

  As a result, the rigidity (expansion spring constant K) of the diaphragm 30 can be lowered during vibration input with normal amplitude, so that the liquid flow effect between the main liquid chamber 11A and the sub liquid chamber 11B by the orifice 25 can be efficiently performed. (Both refer to FIG. 1), and sufficient attenuation performance can be secured.

  On the other hand, when a large amplitude vibration is input, the rigidity (expansion spring constant K) of the diaphragm 30 can be increased, so that the pressure drop in the main liquid chamber 11A (see FIG. 1) is suppressed and the occurrence of cavitation is suppressed. can do.

  That is, in a state where a large amplitude vibration is input and the diaphragm 30 is greatly expanded (for example, the input amount h = 2 mm in FIG. 6), the expansion spring constant K is increased. The flow of the liquid to 11B can be made difficult to flow (flow is slowed down). As a result, a state in which a sufficient amount of liquid remains in the main liquid chamber 11A is ensured, and the inside of the main liquid chamber 11A is difficult to be evacuated (that is, the pressure drop in the main liquid chamber 11A is suppressed). Therefore, even if the input direction is reversed and the fluid flows from the sub liquid chamber 11B to the main liquid chamber 11A, the pressure drop in the main liquid chamber 11A is suppressed and the occurrence of cavitation is suppressed. be able to.

  FIG. 7 is a graph showing a change in hydraulic pressure in the main liquid chamber 11A. In this graph, a large amplitude vibration (frequency: 10 Hz, amplitude (input displacement L): 2 mm) is input to the liquid-filled vibration isolator 100 in a sine waveform, and the change of the pressure P in the main liquid chamber 11A at that time is shown. It is the measurement result which measured. The horizontal axis represents time T, the first vertical axis (left side in FIG. 7) represents the pressure P in the main liquid chamber 11A, the second vertical axis (right side in FIG. 7) represents the input displacement L to the liquid-filled vibration isolator 100, Each is shown.

  The “invention product” and “conventional product” shown in FIG. 7 correspond to the “invention product” and “conventional product” shown in FIG. 6. In FIG. 7, the pressure P of the “invention product” is indicated by a solid line. The pressure P of the “conventional product” is indicated by a two-dot chain line. In FIG. 7, the input displacement L is indicated by a broken line.

  As shown in FIG. 7, the “conventional product” is an input waveform except for a region where the response waveform of the pressure P in the main liquid chamber 11 </ b> A is 0.1 MPa or less where the saturated vapor pressure of the liquid (the ethylene glycol aqueous solution described above) is reached. It can be seen that the waveform changes in the same way as (sine waveform).

  On the other hand, as shown in FIG. 7, the “invention product” has a response waveform almost identical to that of the “conventional product” in the region where the pressure P in the main liquid chamber 11A is positive, but the pressure in the main liquid chamber 11A. In the region where P is negative pressure, a response waveform different from that of the “conventional product” is shown, and it can be seen that the response waveform of the pressure P in the main liquid chamber 11A is different from the input waveform.

  Specifically, as shown in FIG. 7, in the “invention product”, the response waveform when the pressure P in the main liquid chamber 11 </ b> A becomes negative is greater in the time axis direction than the response waveform when the pressure P becomes positive. The width in the left-right direction (FIG. 7) is narrower. That is, when the pressure P in the main liquid chamber 11A transits from positive pressure to negative pressure, the pressure P in the “invention product” is compared with the decrease rate (gradient of the graph) of the pressure P in the “conventional product”. The rate of decrease (gradient of the graph) is small (slow), and the “invention product” delays the timing more slowly than the “conventional product”, and slowly reduces the pressure P to the saturated vapor pressure.

  On the other hand, when the pressure P in the main liquid chamber 11A that has decreased to the saturated vapor pressure rises, the pressure P in the “invention product” starts to rise at an earlier timing than the change in the pressure P in the “conventional product”. is doing. That is, the “invention product” has a faster recovery of the pressure P than the “conventional product”, and the time for staying at the saturated vapor pressure is shortened.

  As described above, according to the present invention, the recovery of the pressure P in the main liquid chamber 11A can be delayed and the recovery can be accelerated, so that the liquid flow from the main liquid chamber 11A to the sub liquid chamber 11B can be reduced. Therefore, when the liquid flows from the sub liquid chamber 11B to the main liquid chamber 11A, the flow of the liquid can be suppressed. Thereby, at the time of large amplitude vibration input, the pressure drop in the main liquid chamber 11A can be suppressed, and the occurrence of cavitation can be suppressed.

  The present invention has been described above based on the embodiments. However, the present invention is not limited to the above embodiments, and various improvements and modifications can be made without departing from the spirit of the present invention. It can be easily guessed.

  For example, in the above embodiment, the case where the annular portion 33 is made of a metal material has been described. However, the present invention is not necessarily limited to this, and a material having higher rigidity than the flexible portion 31 is sufficient. . Therefore, for example, the annular portion 33 may be made of a resin material (for example, PPA).

  Moreover, although the case where the annular part 33 was comprised by the annular | circular shape continued in the circumferential direction was demonstrated in the said embodiment (refer Fig.4 (a)), it is not necessarily restricted to this, Other structure Of course, it is possible. For example, a part of the annular portion 33 in the circumferential direction may be divided.

  In the above embodiment, the case where the present invention is applied to the so-called single orifice type liquid-filled vibration isolator 100 in which the main liquid chamber 11A and the sub liquid chamber 11B communicate with each other by one orifice 25 has been described. However, the present invention is not necessarily limited to this, and it is naturally possible to apply the present invention to a so-called double orifice type liquid-filled vibration isolator.

  The double orifice type liquid-filled vibration isolator includes a main liquid chamber, two first and second sub liquid chambers, and the first and second sub liquid chambers and the main liquid chamber, respectively. The first and second orifices communicated with each other, and each of the first and second orifices is configured so as to exhibit a liquid flow effect.

It is sectional drawing of the liquid filled type vibration isolator in one embodiment of this invention. (A) is a top view of a diaphragm, (b) is sectional drawing of the diaphragm 30 in the IIb-IIb line | wire of Fig.2 (a). (A) is a top view of an attachment part, (b) is sectional drawing of the attachment part in the IIIb-IIIb line | wire of Fig.3 (a). (A) is a top view of an annular part, (b) is sectional drawing of the annular part in the IVb-IVb line | wire of Fig.4 (a). It is a partial expanded sectional view of a diaphragm. It is a graph which shows the expansion spring constant of a diaphragm. It is a graph which shows the hydraulic pressure change in the main fluid chamber.

100 Liquid-sealed vibration isolator 1 First mounting bracket (first mounting bracket)
2 Second mounting bracket (second mounting bracket)
3 Antivibration Base 11 Liquid Enclosure Chamber 11A Main Liquid Chamber 11B Sub-Liquid Chamber 20 Partition Hardware (Partition Means)
25 Orifice 30 Diaphragm 31 Flexible portion 31a Peripheral membrane portion 31c Central membrane portion 32 Mounting portion 33 Ring portion D1 Mounting portion inner diameter D2 Ring portion outer diameter D3 Ring portion inner diameter O Axis center

Claims (3)

A first mounting tool, a cylindrical second mounting tool, a vibration isolating base that connects the second mounting tool and the first mounting tool and is made of a rubber-like elastic body, and is attached to the second mounting tool A diaphragm that forms a liquid sealing chamber between the anti-vibration base, partition means for partitioning the liquid sealing chamber into a main liquid chamber on the anti-vibration base and a secondary liquid chamber on the diaphragm, and In a liquid-filled vibration isolator having an orifice that allows the liquid chamber and the auxiliary liquid chamber to communicate with each other,
The diaphragm is configured from a metal material in an annular shape when viewed from above, and is attached to the second fixture, and is disposed at a central opening of the mounting portion, and is configured from a metal material or a resin material as viewed from above. An annular portion that is formed, and a flexible portion that is formed integrally with the annular portion and the attachment portion and is configured in a film shape from a rubber-like elastic body,
The flexible portion includes an outer peripheral membrane portion that connects an inner peripheral side of the attachment portion and an outer peripheral side of the annular portion to block between the attachment portion and the annular portion, and a central opening of the annular portion. And a central membrane portion that closes
The diaphragm is configured in a symmetric shape around an axis, and the cross-section of the diaphragm including the axis is a direction in which the central film portion of the flexible portion is close to the partition means in a non-acting state of hydraulic pressure. And the outer peripheral membrane portion of the flexible portion is constructed in an arc shape convex toward the opposite side of the central membrane portion, and the annular portion is Extending in a direction perpendicular to the axis,
The distance between the outer peripheral film part between the inner peripheral side of the attachment part and the outer peripheral side of the annular part is set to be smaller than the inner diameter dimension of the central film part in a direction perpendicular to the axis of the diaphragm,
When a large-amplitude input displacement is input in a sine waveform that alternates between the compression direction and the tensile direction, the pressure response waveform in the main liquid chamber is different from the input waveform, and the pressure in the main liquid chamber A liquid filled type vibration isolator characterized in that the response waveform when negative pressure becomes narrower in time axis direction than the response waveform when negative pressure becomes positive. Before Kienwa unit, compared inner diameter of the mounting portion, according to claim 1, wherein the outer diameter wherein the inner diameter with is set to 1/2 or more is set to 1/3 or more Liquid-filled vibration isolator. The annular portion includes hydraulic antivibration device according to claim 1 or 2, characterized in that the end portion toward the outer peripheral layer portion is formed to the bent shape.

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