JP2007218335A - Liquid sealed vibration absorbing device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a liquid sealed vibration absorbing device having a simple structure while securing a dynamic property and suppressing the occurrence of cavitation. <P>SOLUTION: The liquid sealed vibration absorbing device comprises a first sub liquid chamber 11C having an opening on the side of a first liquid chamber 11A, and a first membrane member 61 for partitioning the first sub liquid chamber 11C from the first liquid chamber 11A. When great negative pressure is generated in the first liquid chamber 11A, the negative pressure is utilized for displacing (flexural deforming) part of the first membrane member 61 to the side of the first liquid chamber 11A to make the first sub liquid chamber 11C communicate with the first liquid chamber 11A. As a result, the volume of the first liquid chamber 11A is substantially increased only by a volume equivalent to the volume of the first sub liquid chamber 11C. A volume increasing effect relaxes negative pressure in the first liquid chamber 11A to suppress the occurrence of cavitation. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a liquid-filled vibration isolator, and more particularly, to a liquid-filled vibration isolator capable of ensuring dynamic characteristics and suppressing cavitation while simplifying the structure.

  A liquid-filled vibration isolator is known as a vibration isolator that supports and fixes an automobile engine and prevents the engine vibration from being transmitted to a vehicle body frame.

  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 first liquid chamber and a second liquid chamber by a partition member, and the first liquid chamber and the second liquid chamber are communicated with each other by an orifice.

  According to this liquid-filled vibration isolator, the vibration damping function and the vibration insulation function can be achieved by the fluid flow effect (liquid column resonance effect) between the two liquid chambers by the orifice and the vibration control effect of the vibration isolating substrate. .

  By the way, in such a liquid-filled vibration isolator, for example, when a large amplitude vibration is input and the pressure in the first liquid chamber changes suddenly, the orifice becomes clogged and the liquid does not flow through the orifice. In this case, when a vibration in a direction in which the first mounting tool is relatively separated from the second mounting tool is input, a large number of liquids in the first liquid chamber are generated along with the negative pressure generated in the first liquid chamber. Cavitation (cavitation phenomenon) occurs in which bubbles are generated and they collapse and disappear.

  Since this cavitation generates an abnormal noise when the bubbles collapse, there is a problem in that the abnormal noise is transmitted into the passenger compartment, resulting in a decrease in quietness and ride comfort. In addition, when the bubbles collapse, a very high pressure is instantaneously generated and damages the surface of the partition member. Therefore, there is a problem that the partition member is damaged by repeating this.

  Various techniques for suppressing the occurrence of cavitation have been proposed. For example, in JP-A-11-201216, in a liquid-filled vibration isolator in which a liquid chamber is divided into two chambers by a partitioning body and these two chambers are communicated with an orifice, a hole having a smaller diameter than that of the orifice is provided. A technique that suppresses the occurrence of cavitation by opening two chambers in a central plate portion of a partition body is disclosed (Patent Document 1).

Further, for example, in Japanese Patent Application Laid-Open No. 2005-48906, a liquid chamber is divided into a main liquid chamber and a sub liquid chamber by a partition member, and the main liquid chamber and the sub liquid chamber are communicated by an orifice passage. In a vibration isolator, a technology that suppresses the occurrence of cavitation by providing the partition member with a check valve that allows the flow of liquid from the sub liquid chamber to the main liquid chamber when a predetermined negative pressure is generated in the main liquid chamber. Is disclosed (Patent Document 2).
Japanese Patent Laid-Open No. 11-201216 JP 2005-48906 A

  However, in the conventional technique described above, in the former (Japanese Patent Laid-Open No. 11-201216), the two chambers are always in communication with each other, so that the liquid flows between the two liquid chambers even through this hole. Since the fluid flow effect between the two liquid chambers via the orifice becomes difficult to obtain (the hydraulic pressure escapes), there is a problem that the dynamic characteristics (attenuation performance) are reduced accordingly. On the other hand, if the hole is configured to have a smaller diameter in order to ensure the damping performance, there is a problem that the generation of cavitation cannot be sufficiently suppressed and abnormal noise is generated.

  Further, in the latter (Japanese Patent Laid-Open No. 2005-48906), it is necessary to newly provide a check valve, which causes an increase in weight and an increase in parts cost and manufacturing cost as the number of parts increases. There was a point. Moreover, since the check valve has a complicated structure including a plurality of parts, there is a problem that reliability and durability are lowered.

  The present invention has been made to solve the above-described problems, and provides a liquid filled type vibration damping device capable of ensuring dynamic characteristics and suppressing cavitation while simplifying the structure. The purpose is to do.

  In order to achieve this object, a liquid-filled vibration isolator according to claim 1 connects a first fixture, a cylindrical second fixture, the second fixture, and the first fixture. And a vibration isolating base composed of a rubber-like elastic body, a diaphragm attached to the second fixture and forming a liquid sealing chamber between the vibration isolating base, and the liquid sealing chamber on the side of the vibration isolating base A partition member that partitions the first liquid chamber and the second liquid chamber on the diaphragm side, and an orifice that is formed on an outer peripheral portion of the partition member and communicates the first liquid chamber and the second liquid chamber. A sub-liquid chamber which is a space formed by the partition member and has an opening on the first liquid chamber side, and is located at an opening of the sub-liquid chamber and divides the sub-liquid chamber and the first liquid chamber And a membrane member made of a rubber-like elastic body. The sub-liquid chamber and the first liquid chamber are communicated with each other by displacing a part of the bren member toward the first liquid chamber side, and the upper surface portion and the lower step portion of the partition member have upper surfaces on the first liquid chamber side. And an inlet / outlet on the first liquid chamber side of the orifice is disposed at a position corresponding to the lower step portion.

  The liquid-filled type vibration damping device according to claim 2 is the liquid-filled type vibration-proof device according to claim 1, comprising a concave portion provided in a lower portion of the partition member and having an opening on the first liquid chamber side, A space formed by the recess is defined as the secondary liquid chamber, and the secondary liquid chamber and the first liquid chamber are partitioned by the membrane member.

  The liquid-filled vibration isolator according to claim 3 is the liquid-filled vibration isolator according to claim 2, wherein the membrane member is attached to the inner peripheral surface of the recess.

  The liquid-filled vibration isolator according to claim 4 is the liquid-filled vibration isolator according to any one of claims 1 to 3, wherein the partition member forms the orifice between the second fixture. A pair of orifice-forming walls projecting radially outward, and a vertical wall that connects the pair of orifice-forming walls to each other and divides the orifice in the circumferential direction, by the pair of orifice-forming walls. Of the space to be formed, the remaining space of the orifice is defined as the secondary liquid chamber, and the secondary liquid chamber and the first liquid chamber are partitioned by the membrane member.

  The liquid-filled vibration isolator according to claim 5 is the liquid-filled vibration isolator according to any one of claims 1 to 4, wherein the lower step portion is formed in a fan shape in a top view of the partition member, The entrance / exit of the orifice is disposed in the sector arc and the center angle of the sector is set to 120 ° or less.

  According to the liquid-filled vibration isolator according to claim 1, the vibration is an input of vibration in a relatively low frequency region, and the first mounting bracket and the second mounting bracket are moved relative to each other in a direction close to each other (hereinafter referred to as the vibration mounting device). , Referred to as “pressurization-side vibration”), the pressure in the first liquid chamber becomes higher than the pressure in the second liquid chamber as the vibration-damping substrate is elastically deformed. The fluid flows from the first liquid chamber to the second liquid chamber via the orifice.

  On the other hand, when vibration that relatively moves the first mounting bracket and the second mounting bracket in a direction away from each other (hereinafter referred to as “reduced pressure side vibration”) is input, along with elastic deformation of the vibration-proof base, As the pressure in the first liquid chamber becomes lower than the pressure in the second liquid chamber, the liquid flows from the second liquid chamber to the first liquid chamber via the orifice.

  As a result, the input vibration is a liquid fluid that flows between the first liquid chamber and the second liquid chamber via the orifice as the pressure in the first liquid chamber changes due to the input vibration. It is attenuated by the flow effect (liquid column resonance effect).

  Here, in the conventional liquid-filled vibration isolator, for example, when a large amplitude vibration (pressurization side vibration) is input and the pressure in the first liquid chamber rises rapidly, the orifice becomes clogged, and the liquid flows into the orifice. No longer flows. In this case, since the pressure change in the first liquid chamber is large, the liquid in the first liquid chamber is accompanied by the negative pressure generated in the first liquid chamber by the input of the vibration (depressurization side vibration) immediately after that. There was a problem that cavitation (cavitation phenomenon) occurred in which a large number of bubbles were generated and collapsed and disappeared.

  On the other hand, in the present invention, a sub liquid chamber which is a space formed by the partition member and has an opening on the first liquid chamber side, and the sub liquid chamber and the first liquid chamber which are located at the opening of the sub liquid chamber, And a membrane member composed of a rubber-like elastic body, and a part of the membrane member is displaced toward the first liquid chamber so that the sub liquid chamber and the first liquid chamber communicate with each other. Therefore, there is an effect that generation of cavitation can be suppressed.

  In other words, according to the present invention, even when a large amplitude vibration (reduced pressure side vibration) is further input while the orifice is clogged and a large negative pressure is generated in the first liquid chamber, this negative pressure is used. Thus, by displacing (flexing deformation) part of the membrane member toward the first liquid chamber, the sub liquid chamber and the first liquid chamber that are partitioned by the membrane member can be communicated with each other.

  This communication allows the volume of the first liquid chamber to be substantially increased by the volume of the sub liquid chamber, so that the negative pressure in the first liquid chamber is relieved by this volume increasing effect, and cavitation is reduced. Occurrence can be suppressed. As a result, it is possible to suppress the generation of abnormal noise, improve silence and ride comfort, and avoid breakage of the partition member due to cavitation.

  When a large amplitude vibration (pressurization side vibration) is input and the orifice is clogged, the secondary liquid chamber and the first liquid chamber are already in communication (for example, a part of the membrane member is in the secondary liquid chamber). When the large-amplitude vibration (depressurization side vibration) is input thereafter, the negative pressure mitigating action due to the volume increase effect described above is effectively achieved. It cannot be demonstrated.

  On the other hand, according to the present invention, since the liquid sealed in the liquid sealing chamber is incompressible, even if a large amplitude vibration (pressure-side vibration) is input, a part of the membrane member remains in the secondary liquid chamber. The secondary liquid chamber and the first liquid chamber can be maintained in a state of being partitioned by the membrane member without being displaced (bending deformation) so as to enter. Therefore, at the time of subsequent pressure reduction side vibration input, the negative pressure mitigating action due to the volume increase effect described above can be effectively exhibited.

  Further, according to the present invention, the sub liquid chamber is formed by the partition member and the membrane member is arranged at the opening of the sub liquid chamber, so that the structure is simpler than that of the conventional product provided with the check valve. Can be As a result, the weight can be reduced, and the number of parts can be reduced to reduce the parts cost and the manufacturing cost and improve the reliability and durability.

  In addition, in the conventional product in which the two chambers of the first liquid chamber and the second liquid chamber are always in communication with each other through the hole, the liquid flows through the hole (hydraulic pressure escapes). There is a problem that it is difficult to obtain a fluid flow effect between the two liquid chambers. On the other hand, according to the present invention, since the sub liquid chamber is configured to communicate with only the first liquid chamber, the liquid pressure is set between the first liquid chamber and the second liquid chamber via the sub liquid chamber. It does not flow (hydraulic pressure escapes). Further, as described above, since the liquid sealed in the liquid sealing chamber is incompressible, the membrane member is displaced (flexed deformation) to the sub liquid chamber side by the input of vibration (pressure-side vibration), and the liquid pressure Will not run away. Therefore, the fluid flow effect (liquid column resonance effect) between the two liquid chambers via the orifice can be efficiently obtained, and the dynamic characteristics (damping performance) can be improved.

  According to the present invention, as described above, when the negative pressure in the first liquid chamber reaches a predetermined value, the membrane member is displaced (flexed) against its own rigidity. In other words, when a relatively small amplitude vibration (depressurization side vibration) is input, the membrane member does not displace (bend deformation) due to its own rigidity, and maintains the state in which the sub liquid chamber and the first liquid chamber are partitioned. To do. Therefore, the fluid flow effect (liquid column resonance effect) of the liquid flowing between the first liquid chamber and the second liquid chamber via the orifice can be efficiently obtained. Further, it is possible to avoid the problem that the flow of the liquid is hindered by the deformed (flexible deformation) membrane member, and to stably exhibit desired dynamic characteristics.

  Here, according to the present invention, the partition member is formed in a step shape in which the upper surface on the first liquid chamber side has an upper step portion and a lower step portion, and the inlet / outlet on the first liquid chamber side of the orifice corresponds to the lower step portion. Since it is disposed at the position, the separation distance between the lower step portion and the vibration isolating substrate can be made longer than the separation distance between the upper step portion and the vibration isolating substrate.

  As a result, even when a large amplitude vibration (decompression side vibration) is further input in a state where the orifice is clogged, and a large negative pressure is generated in the first liquid chamber, the upper portion is increased by the longer separation distance described above. As compared with the above, the negative pressure in the lower stage can be made smaller. As a result, the liquid flow in the vicinity of the inlet / outlet on the first liquid chamber side of the orifice (that is, the portion corresponding to the lower step) is suppressed from being influenced by cavitation, and the desired dynamic characteristic (damping characteristic) is stabilized. There is an effect that can be exhibited.

  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 liquid-filled vibration isolator has a recess in the lower part of the partition member and has an opening on the first liquid chamber side. Since the space formed by the recess is configured as a sub liquid chamber and the sub liquid chamber and the first liquid chamber are partitioned by the membrane member, the opening of the sub liquid chamber (that is, the membrane member) is formed at the lower stage. It can be positioned opposite to the bottom surface of the vibration-proof substrate.

  Here, the bottom surface portion of the vibration-isolating base functions as a piston portion that applies a pressure change to the first liquid chamber to flow the liquid. According to the present invention, as described above, the bottom surface portion is located at a position facing the piston portion. Since the opening (membrane member) of the secondary liquid chamber is arranged, when a negative pressure is applied by the piston, a part of the membrane member can be surely displaced (flexed deformation) in conjunction with this pressure change. it can.

  As a result, when a large amplitude vibration (depressurization side vibration) is input with the orifice clogged and a large negative pressure is generated in the first liquid chamber, a part of the membrane member is moved to the first liquid chamber side. The displacement (bending deformation) can be reliably performed, and the negative pressure in the first liquid chamber can be relieved by the above-described volume increase effect, and the occurrence of cavitation can be reliably suppressed.

  Further, according to the present invention, as described above, since the opening of the sub liquid chamber is located in the lower step, cavitation in the lower step can be intensively suppressed. As a result, the flow of liquid in the vicinity of the inlet / outlet on the first liquid chamber side of the orifice (that is, the portion corresponding to the lower part) is suppressed from being influenced by cavitation, and the desired dynamic characteristic (damping characteristic) is stabilized. There is an effect that can be exhibited.

  According to the liquid-filled vibration isolator of claim 3, in addition to the effect exhibited by the liquid-filled vibration isolator of claim 2, the membrane member is attached to the inner peripheral surface of the recess. The member can be displaced (bend deformation) without causing it to collide with the partition member, and as a result, it is possible to avoid the generation of abnormal noise due to the collision.

  According to the liquid-filled vibration isolator of claim 4, in addition to the effect exhibited by the liquid-filled vibration isolator according to any one of claims 1 to 3, the orifice in the space formed by the orifice forming wall Therefore, there is an effect that the space that becomes a dead space can be effectively used without having the function as an orifice. As a result, the secondary liquid chamber can be formed while ensuring the capacity of the orifice, so that the vibration damping function by the fluid flow effect using the orifice (liquid column resonance effect) without causing an increase in the size of the vibration isolator. In addition, it is possible to achieve a coexistence of a negative pressure mitigating action by a volume increase effect using the sub liquid chamber.

  Further, according to the present invention, since the opening (that is, the membrane member) of the sub liquid chamber can be disposed at a position adjacent to the inlet / outlet on the first liquid chamber side of the orifice, the liquid pressure ( (Negative pressure) can be appropriately transmitted to the membrane member, and a part of the membrane member can be reliably displaced (flexed deformation) by the negative pressure in the first liquid chamber.

  As a result, when a large amplitude vibration (depressurization side vibration) is input with the orifice clogged and a large negative pressure is generated in the first liquid chamber, a part of the membrane member is moved to the first liquid chamber side. Displacement (bending deformation) is performed, and the above-described volume increase effect is reliably exhibited, and the negative pressure in the first liquid chamber is alleviated, so that the occurrence of cavitation can be reliably suppressed.

  Furthermore, according to the present invention, as described above, since the opening (membrane member) of the secondary liquid chamber is located adjacent to the inlet / outlet on the first liquid chamber side of the orifice, cavitation in the vicinity of the inlet / outlet is focused on. Can be suppressed. As a result, the flow of the liquid in the vicinity of the inlet / outlet on the first liquid chamber side of the orifice is suppressed from being influenced by cavitation, and the desired dynamic characteristic (attenuation characteristic) can be stably exhibited. is there.

  Further, according to the present invention, the sub liquid chamber and the orifice face each other across the inlet / outlet on the first liquid chamber side of the orifice, that is, the flow direction of the liquid from the inlet / outlet on the first liquid chamber side of the orifice toward the orifice Since the sub liquid chamber is located on the opposite side, when the liquid flows from the first liquid chamber to the orifice by inputting vibration (pressurization side vibration), the flow of the liquid is affected by the membrane member. Can be avoided. Thereby, the fluid flow effect (liquid column resonance effect) between the two liquid chambers via the orifice can be efficiently obtained, and the dynamic characteristics (damping performance) can be improved.

  According to the liquid-filled vibration isolator according to claim 5, in addition to the effect exhibited by the liquid-filled vibration isolator according to any one of claims 1 to 4, the lower step portion is formed in a fan shape in a top view of the partition member. In addition, since the inlet / outlet on the first liquid chamber side of the orifice is arranged in the fan-shaped arc, generation of cavitation in the vicinity of the inlet / outlet can be intensively suppressed. As a result, the flow of the liquid in the vicinity of the inlet / outlet on the first liquid chamber side of the orifice is suppressed from being influenced by cavitation, and the desired dynamic characteristic (attenuation characteristic) can be stably exhibited. is there.

  In addition, according to the present invention, the lower stage portion has a sector-shaped central angle set to 120 ° or less, so that the volume ratio of the space formed by the lower stage portion with respect to the first liquid chamber is optimized and described above. There is an effect that the negative pressure mitigating action by the volume increasing effect using the sub liquid chamber can be efficiently exhibited.

  In other words, if the central angle of the sector is set to a value larger than 120 °, the volume ratio of the space formed by the lower stage portion to the first liquid chamber increases, and accordingly, the negative pressure is alleviated by the volume increase effect. It is necessary to increase the volume of the sub liquid chamber in order to fully exert the action. However, when the volume of the secondary liquid chamber is increased, it is necessary to increase the size of the membrane member as the size of the opening of the secondary liquid chamber increases. As a result, the response performance of the displacement (flexure deformation) of the membrane member decreases. Therefore, there arises a problem that the negative pressure relaxation action due to the volume increase effect described above cannot be properly exhibited.

  On the other hand, according to the present invention, since the sector-shaped central angle is set to 120 ° or less, the volume ratio of the space formed by the lower stage portion to the first liquid chamber can be optimized. Thereby, since it is not necessary to unnecessarily increase the volume of the secondary liquid chamber, the membrane member can be reduced in size, and the response performance of the displacement (bending deformation) of the membrane member can be improved. As a result, the negative pressure mitigating action due to the volume increase effect described above can be efficiently exhibited.

  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. As shown in FIG. 1, mounting bolts 1 a and positioning pins protrude from the upper end surface of the first mounting bracket 1. Further, a substantially flange-shaped protruding portion is formed on the outer peripheral portion of the first mounting portion 1, and the protruding portion comes into contact with the stabilizer fitting 13 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. A mounting bolt 6 and a positioning pin 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. In addition, a rubber film 7 covering the inner peripheral surface of the cylindrical metal fitting 4 is connected to the lower end portion of the vibration-isolating base 3, and the rubber film 7 has orifice forming walls 22 and 23 ( For example, refer to FIG. 2), and the orifice 25 is formed.

  The diaphragm 9 is formed in a rubber film shape having a partial spherical shape from a rubber-like elastic body, and is vulcanized and bonded to a mounting plate 10 having a donut shape when viewed from above. As shown in FIG. 1, the diaphragm 9 is attached to the second mounting bracket 2 by fixing the mounting plate 10 together with the raised plate 14 between the cylindrical metal fitting 4 and the bottom metal fitting 5. . As a result, a liquid sealing chamber 8 is formed between the diaphragm 9 and the lower surface of the vibration isolating substrate 3.

  The liquid enclosure 8 is filled with an antifreeze liquid (not shown) such as ethylene glycol. Further, as shown in FIG. 1, the liquid sealing chamber 8 is partitioned into two chambers, a first liquid chamber 11A on the vibration-isolating base 3 side and a second liquid chamber 11B on the diaphragm 9 side, by a partition member 12 described later. It has been.

  As shown in FIG. 1, the partition member 12 is internally fitted and held in a main body portion 20 in which orifice forming walls 22 and 23 are formed on the outer peripheral portion and an opening on the lower surface side (lower side in FIG. 1) of the main body portion 20. The bottom plate 30 is mainly provided with a first membrane member 61 and a second membrane member 62 that are formed in a film shape from a rubber-like elastic body.

  In addition, the partition member 12 is hold | maintained between the raising board 14 and the step part 57 of the vibration isolator base | substrate 3, as shown in FIG. That is, the partition member 12 is inserted into the second mounting bracket 2 (cylindrical bracket 4) in a state where the step portion 57 of the vibration isolation base 3 is compressed and deformed in the axial direction (vertical direction in FIG. 1). It is held in the liquid sealing chamber 8 by the elastic restoring force of the base 3 (step 57).

  An orifice 25 is formed between the outer peripheral surface of the main body 20 and the rubber film 7 covering the inner peripheral surface of the second mounting bracket 2 as shown in FIG. The orifice 25 is an orifice channel for communicating the first liquid chamber 11A and the second liquid chamber 11B, and for allowing the liquid to flow between the two liquid chambers 11A and 11B, and the partition member 12 (main body portion 20). Is formed around the axial center O (see FIG. 2).

  Next, the partition member 12 will be described with reference to FIGS. FIG. 2 is a perspective view of the partition member 12, and FIGS. 3A and 3B are a top view and a front view of the partition member 12. 4A is a bottom view of the partition member 12, and FIG. 4B is a cross-sectional view of the partition member 12 taken along line IVa-IVa in FIG. 3A. FIG. 5 is a cross-sectional view of the partition member 12 taken along the line Vb-Vb in FIG.

  As described above, the partition member 12 is a member for partitioning the liquid sealing chamber 8 into the first liquid chamber 11A and the second liquid chamber 11B (see FIG. 1), and the main body 20 and the bottom plate 30 are mainly used. It is configured to prepare for. As shown in FIGS. 2 to 5, the main body 20 and the bottom plate 30 are formed in a substantially circular plate shape having a shaft core O from a thermoplastic resin material. It is fitted and held.

  A pair of orifice-forming walls 22 and 23 are formed on the upper and lower ends in the axial direction of the main body 20 so as to protrude radially outwardly in a substantially flange shape, and the opposing surfaces of the pair of orifice-forming walls 22 and 23 are formed. An orifice channel is formed between them.

  As described above, the orifice forming walls 22 and 23 are in close contact with the rubber film 7 covering the inner periphery of the cylindrical metal fitting 4 to form the orifice 25 having a substantially rectangular cross section (see FIG. 1). Further, as shown in FIGS. 2 to 5, the main body portion 20 includes a vertical wall 24 that connects the upper and lower orifice forming walls 22 and 23, and the orifice 25 (see FIG. 1) is formed by the vertical wall 24. Divided (partitioned) in the circumferential direction.

  As shown in FIGS. 2, 3, and 4 (b), a cutout 55 is formed in the upper orifice forming wall 22 and the main body 20, and the orifice flow path is formed through the cutout 55. One end of the orifice 25 (see FIG. 1) communicates with the first liquid chamber 11A. That is, the notch 55 is an entrance / exit of the orifice 25 on the first liquid chamber 11A side.

  On the other hand, a notch 56 is formed in the lower orifice forming wall 23 and the main body portion 20, and the other end of the orifice channel (orifice 25, see FIG. 1) is formed through the notch 56. It communicates with the two liquid chamber 11B. That is, the notch 56 is an entrance / exit of the orifice 25 on the second liquid chamber 11B side.

  As shown in FIGS. 2 to 4, the main body 20 has a stepped shape in which the upper surface side (for example, FIG. 3 (a) front side of FIG. 3A) on the first liquid chamber 11 </ b> A side has an upper step portion 21 a and a lower step portion 21 b. In the position corresponding to the lower step portion 21b, the inlet / outlet (that is, the notch 55) of the orifice 25 on the first liquid chamber 11A side is disposed.

  In addition, as shown in FIG. 3A, the lower step portion 21a is formed in a fan shape in the top view of the partition member 12, and the inlet / outlet on the first liquid chamber 11A side of the orifice 25 (that is, in the fan-shaped arc portion) A notch 55) is disposed, and the central angle of the sector is set to 100 ° in the present embodiment. The central angle is preferably set to 120 ° or less.

  As shown in FIG. 4B, a through hole 26 is formed in the lower step portion 21 b of the main body portion 20, and the bottom surface side of the through hole 21 b is sealed with a plate member 30. Accordingly, a recess having an opening on the first liquid chamber 11A (see FIG. 1) side, that is, the first sub liquid chamber 11C is formed in the lower stage portion 21a of the main body section 20, and the first sub liquid chamber is formed. The first membrane member 61 is vulcanized and bonded to the C opening.

  The first membrane member 61 is a member for partitioning the first sub-liquid chamber 11C and the first liquid chamber 11A, and is configured in a circular shape in a top view from a rubber-like elastic body as shown in FIG. 2 or FIG. ing. In the first membrane member 61, a part of the outer peripheral edge portion (40% in the circumferential direction in the present embodiment) is vulcanized and bonded to the inner peripheral surface of the through hole 26. Thereby, as will be described later, a part of the first membrane member 61 is displaced toward the first liquid chamber 11A, whereby the first sub-liquid chamber 11C and the first liquid chamber 11A are communicated (FIG. 6 ( a) and FIG. 6 (c)).

  The upper surface of the first membrane member 61 is set to the same height as the upper surface of the lower step portion 21b as shown in FIG. 4B. Thereby, the upper part of the lower step part 21b is configured to be flush with a step, so that the liquid can flow smoothly.

  Further, as shown in FIGS. 2 to 5, the partition member 12 is a space that is the remainder of the orifice 25 in the space formed by the pair of orifice forming walls 22, 23, that is, the vertical wall 24 and the notch 55. A space formed between the second sub-liquid chamber 11D and the second membrane member 62 is vulcanized and bonded to the opening of the second sub-liquid chamber 11D.

  The second membrane member 62 is a member for partitioning the second auxiliary liquid chamber 11D and the first liquid chamber 11A. As shown in FIGS. 2 to 5, the second membrane member 62 is rectangular in front view corresponding to the cross-sectional shape of the orifice 25. The shape is composed of a rubber-like elastic body. Only one side of the second membrane member 62 corresponding to the orifice forming wall 22 is vulcanized and bonded to the inner peripheral surface of the orifice forming wall 22. Thereby, as will be described later, a part of the second membrane member 62 is displaced to the first liquid chamber 11A side, whereby the second sub liquid chamber 11D and the first liquid chamber 11A communicate with each other through the notch 55. (See FIG. 6C and FIG. 6D).

  Next, with reference to FIG. 6, an operation in which the first and second auxiliary liquid chambers 11C and 11D and the first and second membrane members 61 and 62 suppress the occurrence of cavitation when vibration is input will be described. .

  6A and 6C are cross-sectional views of the partition member 12, and FIGS. 6B and 6D are front views of the partition member 12. 6 (a) and 6 (b) show the state where the pressure side vibration is inputted, and FIGS. 6 (c) and 6 (d) show the state where the decompression side vibration is inputted. .

  When vibration (pressure-side vibration) that moves the first mounting bracket 1 and the second mounting bracket 2 relative to each other in the direction close to each other is input, the inside of the first liquid chamber 11 </ b> A accompanies elastic deformation of the vibration-proof base 3. Is higher than the pressure in the second liquid chamber 11B, the liquid flows from the first liquid chamber 11A to the second liquid chamber 11B through the orifice 25.

  On the other hand, when vibration (reduced pressure side vibration) that moves the first mounting bracket 1 and the second mounting bracket 2 relative to each other in a direction away from each other is input, the first liquid chamber is generated along with the elastic deformation of the vibration-proof base 3. Since the pressure in 11A becomes lower than the pressure in the second liquid chamber 11B, the liquid flows from the second liquid chamber 11B to the first liquid chamber 11A through the orifice 25.

  As a result, the input vibration flows between the first liquid chamber 11A and the second liquid chamber 11B through the orifice as the pressure in the first liquid chamber 11A changes due to the input vibration. Is attenuated by the fluid flow effect (liquid column resonance effect).

  Here, in the conventional liquid-filled vibration isolator, there is a problem that cavitation (cavitation phenomenon) occurs in the first liquid chamber when the decompression side vibration is input while the orifice is clogged. .

  On the other hand, in the liquid-filled vibration isolator 100 of the present invention, the first and second membrane members 61 and 62 are disposed in the openings of the first and second sub liquid chambers 11C and 11D. As shown in FIG. 6C or FIG. 6D, a part of the first and second membrane members 61 and 62 is displaced toward the first liquid chamber 11A, thereby suppressing the occurrence of cavitation. it can.

  Specifically, for example, a large amplitude vibration (pressurization side vibration) is input, and as shown in FIGS. 6A and 6C, a large amplitude vibration (decompression side) with the orifice clogged. (Vibration) is further input, and when a large negative pressure is generated in the first liquid chamber 11A, as shown in FIGS. 6C and 6D, the negative pressure generated in the first liquid chamber 11A is generated. Using the pressure, a part of the first and second membrane members 61, 62 was displaced (flexed deformation) toward the first liquid chamber 11A, and was partitioned by the first and second membrane members 61, 62. The first and second sub liquid chambers 11C and 11D and the first liquid chamber 11A can be communicated with each other.

  By this communication, the volume of the first liquid chamber 11A can be substantially increased by the volume of the first and second sub liquid chambers 11C, 11D. It is possible to relieve the negative pressure inside and suppress the occurrence of cavitation. As a result, it is possible to suppress the generation of abnormal noise and improve quietness and ride comfort, and avoid damage to the partition member 12 (surface on the first liquid chamber 11A side of the main body portion 20) due to cavitation. be able to.

  Here, when a large amplitude vibration (pressurization side vibration) is input and the orifice 25 is clogged, the first sub liquid chamber 11C or the second sub liquid chamber 11D and the first liquid chamber 11A are already in communication with each other. (For example, when a part of the first or second membrane member 61, 62 is displaced (bend deformation) so as to enter the first or second sub liquid chamber 11C, 11D) When amplitude vibration (reduced pressure side vibration) is input, the above-described negative pressure relaxation action due to the volume increase effect cannot be effectively exhibited.

  On the other hand, in the liquid-filled vibration isolator 100 of the present invention, the liquid sealed in the liquid-filled chamber 8 is incompressible, so even if a large amplitude vibration (pressure-side vibration) is input, the first Alternatively, the second membrane members 61 and 62 are not displaced (bent and deformed) so that a part of the second membrane members 61 and 62 enters the first or second auxiliary liquid chambers 11C and 11D, as shown in FIGS. 6 (a) and 6 (b). As shown, the first and second auxiliary liquid chambers 11C and 11D and the first liquid chamber 11A can be maintained in a state of being partitioned by the first and second membrane members 61 and 62. Therefore, at the time of the subsequent input of the decompression-side vibration, the negative pressure mitigating action due to the volume increase effect described above can be effectively exhibited.

  Further, as described above, the upper surface (upper side surface in FIG. 6) of the first liquid chamber 11A is formed in a stepped shape having the upper step portion 21a and the lower step portion 21b, and the partition member 12 is formed in the first liquid chamber of the orifice 25. Since the entrance / exit (notch 55) on the 11A side is disposed at a position corresponding to the lower step portion 21b, the lower step portion 21b and the vibration isolation substrate are compared with the separation distance between the upper step portion 21a and the vibration isolation substrate 3. 3 can be made longer (see FIG. 1).

  As a result, even when a large amplitude vibration (depressurization side vibration) is further input in a state where the orifice 25 is clogged and a large negative pressure is generated in the first liquid chamber 11A, the above-mentioned separation distance is longer. The negative pressure in the lower step portion 21b can be made smaller than that in the upper step portion 21a. As a result, the liquid flow in the vicinity of the inlet / outlet of the orifice 25 on the first liquid chamber 11A side (that is, the portion corresponding to the lower step portion 21b) is suppressed from being influenced by cavitation, and desired dynamic characteristics (damping characteristics). ) Can be exhibited stably.

  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-described embodiment, the case where the range in which the first membrane member 61 is vulcanized and bonded to the inner peripheral surface of the through hole 26 is 40% in the circumferential direction has been described, but the present invention is not necessarily limited thereto. However, it is preferable that the vulcanization adhesion range is set to a range of 30% or more and 50% or less in the circumferential direction. If the vulcanization adhesion range is less than 30% in the circumferential direction, the displacement (flexure deformation) of the first membrane member 61 becomes excessive and the negative pressure relaxation action becomes unstable, while the vulcanization adhesion range is greater than 50% in the circumferential direction. This is because the displacement (flexure deformation) of the first membrane member 61 becomes insufficient, and the negative pressure relaxation action cannot be fully exhibited.

  Further, in this case, the bonding position of the first membrane member 61 to the through hole 26 is located on the axis O side of the main body portion 20, that is, the non-bonding position of the first membrane member 61 is located on the notch 55 side. It is preferable to do. The liquid flow in the vicinity of the inlet / outlet (notch 55) on the first liquid chamber 11A side of the orifice 25 is effectively suppressed from being influenced by cavitation, and desired dynamic characteristics (damping characteristics) are stably exhibited. It is because it can be made.

  In the above embodiment, the case where the second membrane member 62 is vulcanized and bonded to the inner peripheral surface of the orifice forming wall 22 is described. However, the present invention is not necessarily limited to this, and vulcanized and bonded to other locations Of course it is possible. For example, the second membrane member 62 may be vulcanized and bonded to the outer peripheral surface portion of the main body portion 20.

  In the above embodiment, the case where the first sub liquid chamber 11C and the first membrane member 61 are provided in the lower step portion 21b has been described. However, the present invention is not necessarily limited thereto, and instead of this, or in addition to this. Of course, it is possible to provide the auxiliary liquid chamber in another location. For example, a secondary liquid chamber may be provided in a side wall portion connecting the upper step portion 21a and the lower step portion 21b.

  In the above embodiment, the case where the through-hole 26 is formed in a circular cross section has been described. However, the present invention is not necessarily limited to this, and other shapes can naturally be adopted. For example, an elliptical shape, a rectangular shape, or a polygonal shape is exemplified.

It is sectional drawing of the liquid filled type vibration isolator in one embodiment of this invention. It is a perspective view of a partition member. (A) is a top view of a partition member, (b) is a front view of a partition member. (A) is a bottom view of a partition member, (b) is sectional drawing of the partition member in the IVa-IVa line | wire of Fig.3 (a). It is sectional drawing of the partition member in the Vb-Vb line | wire of FIG.3 (b). (A) And (c) is sectional drawing of a partition member, (b) And (d) is a front view of a partition member.

Explanation of symbols

100 Liquid-sealed vibration isolator 1 First mounting bracket (first mounting bracket)
2 Second mounting bracket (second mounting bracket)
3 Antivibration Base 8 Liquid Enclosure Chamber 9 Diaphragm 11A First Liquid Chamber 11B Second Liquid Chamber 11C First Sub Liquid Chamber (Sub Liquid Chamber)
11D Second sub-liquid chamber (sub-liquid chamber)
12 Partition member 21a Upper step portion 21b Lower step portion 22, 23 Orifice forming wall 24 Vertical wall 25 Orifice 26 Through hole (part of recess)
30 Bottom plate (part of recess)
55 Notch (entrance on the first fluid chamber side of the orifice)
61 First membrane member (membrane member)
62 Second membrane member (membrane member)

Claims (5)

A first fixture, a cylindrical second fixture, a vibration isolating base that connects the second fixture and the first fixture and is made of a rubber-like elastic body, and the second fixture. A diaphragm which is attached and forms a liquid sealing chamber between the vibration isolating substrate, a partition member which partitions the liquid sealing chamber into a first liquid chamber on the vibration isolating substrate side and a second liquid chamber on the diaphragm side; In a liquid-filled vibration isolator comprising an orifice formed on an outer peripheral portion of the partition member and communicating the first liquid chamber and the second liquid chamber,
A space formed by the partition member and having an opening on the first liquid chamber side, and located at the opening of the sub liquid chamber to partition the sub liquid chamber and the first liquid chamber A membrane member composed of a rubber-like elastic body, and the sub-liquid chamber and the first liquid chamber communicate with each other by displacing a part of the membrane member to the first liquid chamber side,
The partition member is formed in a stepped shape having an upper surface portion and a lower step portion on an upper surface on the first liquid chamber side, and an inlet / outlet on the first liquid chamber side of the orifice is disposed at a position corresponding to the lower step portion. A liquid-filled vibration isolator characterized by comprising: A concave portion provided in a lower step of the partition member and having an opening on the first liquid chamber side;
2. The liquid filled type vibration damping device according to claim 1, wherein the space formed by the recess is the sub liquid chamber, and the sub liquid chamber and the first liquid chamber are partitioned by the membrane member. .   3. The liquid filled type vibration damping device according to claim 2, wherein the membrane member is attached to an inner peripheral surface of the concave portion. The partition member includes a pair of orifice-forming walls projecting radially outward to form the orifice between the second fixture and the pair of orifice-forming walls connected to each other. A vertical wall that divides in the circumferential direction,
Of the space formed by the pair of orifice forming walls, the space that becomes the remaining portion of the orifice is defined as the sub liquid chamber, and the sub liquid chamber and the first liquid chamber are partitioned by the membrane member. The liquid-filled vibration isolator according to any one of claims 1 to 3.   The lower step portion is formed in a fan shape in a top view of the partition member, and an inlet / outlet on the first liquid chamber side of the orifice is disposed at a portion of the fan arc and a central angle of the fan shape is 120 ° or less. The liquid-filled vibration isolator according to any one of claims 1 to 4, wherein

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