JP2006283779A - Liquid seal type vibration damper - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a vibration damper capable of absorbing low frequency vibration by a simple and low cost structure in a liquid seal type vibration damper. <P>SOLUTION: A diaphragm 5 forming a liquid chamber F1 in an elastic bearing member 4 is formed of a thin-walled center part 5a and a thick-walled outer peripheral part 5b. A projected part 5c of roughly ring-shape in plan view projected to the inside of the liquid chamber F1 is formed between the outer peripheral part 5b and the inner peripheral side, i.e., the center part 5a. In this constitution, when the low frequency vibration is input, the center part 5a of the diaphragm 5 is relatively largely deformed by a variation in liquid pressure produced in the liquid chamber F1 to produce a flow in a damping liquid. An input vibration can be damped by a flow resistance caused by the flow of the damping liquid. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention mainly relates to a liquid-filled vibration isolator for supporting a vibration generator such as an automobile engine.

  Conventionally, as this type of liquid-filled vibration isolator, for example, as disclosed in Patent Document 1, a first mounting member connected to a vibration receiving side (support side) of a vehicle body frame and the like and vibration of an engine or the like A second mounting member connected to the source side (supported side) is connected by an elastic member so that a liquid chamber is defined between them, and vibration from the vibration source side is caused by elastic deformation of the elastic member. Those that absorb water are generally known. In this type of vibration isolator, a liquid chamber partitioned and formed inside the elastic member is divided into a main liquid chamber whose hydraulic pressure varies due to elastic deformation of the elastic member by a partition plate, and a hydraulic pressure fluctuation of the main liquid chamber. In addition, an orifice passage that communicates the main liquid chamber and the sub liquid chamber is provided to attenuate vibration transmitted from the vibration source side.

  For example, as shown in FIG. 12, in the vibration isolator 100, a liquid chamber F is formed in the elastic member 103 that connects the first mounting member 101 having a substantially cylindrical shape and the second mounting member 102 having a substantially cylindrical shape. Thus, the elastic membrane member 104 is provided, and the liquid chamber F is divided into the main liquid chamber F1 and the sub liquid chamber F2 by the partition plate 105 disposed in the liquid chamber F. ing.

Further, an orifice plate 106 is disposed between the elastic membrane member 104 and the partition plate 105, and the main liquid chamber F1 is disposed through a double spiral orifice passage S formed on the outer periphery of the orifice plate 106. And the auxiliary liquid chamber F2 communicate with each other, and low-frequency vibration is attenuated by the flow resistance of the liquid moving in the communication path S.
JP 2004-251438 A

  However, the vibration isolator provided with the orifice passage as described above requires an orifice plate for forming the orifice passage and a partition plate for dividing the liquid chamber into two parts. There is a problem that the process becomes complicated and the manufacturing cost increases.

  The present invention has been made in view of the above points, and the object of the present invention is to simplify the structure of the elastic film member that partitions the liquid chamber in the liquid-filled vibration isolator. Another object of the present invention is to provide a vibration isolator capable of absorbing low frequency vibration with a low cost structure.

  In order to achieve the above object, in the liquid-filled vibration isolator according to the present invention, a thick portion is formed so as to surround the thin portion of the elastic membrane member and protrude toward the liquid chamber. The orifice and the secondary liquid chamber are partitioned in the liquid chamber by the section.

  Specifically, in the first aspect of the invention, the two attachment members respectively connected to the vibration source side and the vibration receiving side and the both attachment members are elastically connected, and the two attachment members are relatively displaced by elastic deformation. It is premised on a liquid-filled vibration isolator including an elastic member and an elastic film member that partitions and forms a liquid chamber filled with liquid inside the elastic member. The elastic membrane member has a thin portion for absorbing a change in volume of the liquid chamber accompanying relative displacement of the two mounting members, and a thickness provided so as to protrude at least around the thin portion toward the liquid chamber. A sub-liquid chamber that is surrounded by the thin-walled portion and the thick-walled portion, and whose volume changes with deformation of the thin-walled portion, and fluid flow to the sub-liquid chamber. It is assumed that a road is formed.

  With this configuration, when the elastic member bends due to vibration input to the vibration isolator and the liquid chamber expands and contracts to change its volume, the entire elastic film member that partitions the liquid chamber is deformed accordingly. However, at this time, the thin part of the elastic film member has a lower rigidity than the thick part, so that it is relatively greatly deformed to expand and contract the sub liquid chamber constituted by the thin part and the thick part. As a result, the liquid flows in the flow passage formed so as to communicate with the sub liquid chamber, and the input vibration is attenuated by the flow resistance at this time. That is, the flow passage formed in the elastic membrane member functions as an orifice passage having a conventional structure, and the same operation and effect can be obtained.

  Therefore, with the above-described configuration, low-frequency vibrations can be effectively damped even if members such as an orifice plate and a partition plate that are conventionally required for forming the orifice passage are omitted. In addition, the overall structure of the vibration isolator can be simplified.

  In the above-described configuration, the thick part of the elastic film member includes at least a cylindrical outer peripheral thick part surrounding the flow passage and a columnar inner peripheral thick part located on the liquid chamber inner side in the outer peripheral thick part. The flow path is formed between the outer peripheral thick part and the inner peripheral thick part, and the thin part is a ring that connects the outer peripheral thick part and the inner peripheral thick part on the outer side of the liquid chamber. Preferably, it is formed in a shape (invention of claim 2). In this way, by forming the flow passage between the inner and outer thick wall portions, the flow passage area becomes relatively small, and the frequency at which liquid column resonance occurs in the flow passage can be lowered. , It will be possible to attenuate the lower frequency vibration.

  Further, as described above, in the case where the thick part of the elastic membrane member is constituted by the inner peripheral thick part and the outer peripheral thick part surrounding it, the inner peripheral thick part includes the inner part of the liquid chamber. It is preferable that at least one recess opening toward the surface is formed (the invention of claim 3). Thus, by providing a hole in the inner peripheral thick part, the portion of the inner peripheral thick part provided with the hole is thinner than other parts, and the liquid pressure in the liquid chamber is reduced. Fluctuations tend to cause minute deformation. As a result, when high-frequency vibration is transmitted to the vibration isolator, the liquid moves microscopically in the hole portion, so that the high-frequency vibration can be attenuated by the flow resistance of the liquid. That is, by providing the hole in the inner peripheral thick portion as described above, not only the low frequency vibration can be attenuated due to the deformation of the thin portion, but also the high frequency vibration can be attenuated.

  Further, a shielding portion that closes a part of the opening end of the flow passage on the liquid chamber side may be formed integrally with the thick portion of the elastic membrane member (invention of claim 4). In this way, when the thin part of the elastic membrane member is deformed and the liquid moves in the flow path, the shielding part acts as a resistance and functions as an orifice so that the low frequency vibration is attenuated. Become.

  As described above, according to the liquid-filled vibration isolator according to the present invention, the elastic film member that partitions the liquid chamber inside the elastic member is surrounded by the thin portion that absorbs the volume change of the liquid chamber and the thin portion. In the case where the vibration is transmitted to the vibration isolator, the sub liquid chamber and the flow passage are formed by the thin portion and the thick portion. The thin wall portion is deformed more than the thick wall portion due to the fluid pressure fluctuation in the liquid chamber, and the liquid in the liquid chamber and the sub liquid chamber moves relative to each other in the flow passage due to the deformation. As a result, since the flow passage functions as an orifice, it is possible to obtain an inexpensive vibration isolator that can absorb low-frequency vibrations with a simple configuration without providing a partition plate or the like as in the conventional structure.

  Further, the thick part is constituted by an inner peripheral thick part and an outer peripheral thick part, and a communication path is formed between the inner peripheral thick part and the outer peripheral thick part, or a communication path is connected to the thick part. By integrally forming the shielding portion so as to block a part of the vibration, it is possible to adjust the frequency range of vibration that can be damped. Furthermore, by providing a concave portion that opens toward the inside of the liquid chamber in the inner peripheral thick wall portion, the concave portion functions as a so-called orifice, so that not only low frequency but also high frequency vibration can be attenuated. Become.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. Note that the following description of the embodiment is merely illustrative in nature, and does not mean that the present invention, its application, or its use is limited.

(Embodiment 1)
As shown in FIG. 1, the vibration isolator 1 according to the first embodiment is a liquid-filled type in which a liquid is sealed. For example, a powertrain (supported body side) of an automobile engine or the like is used. It is interposed between the vehicle body (support side) and supports the load of the power train and attenuates the vibration generated in the power train to suppress the transmission of the vibration to the vehicle body side.

  Specifically, the vibration isolator 1 includes an attachment member 2 connected to a vibration receiving side such as a vehicle body, and another attachment member connected to a vibration source side such as an engine via a casing (not shown). A metallic cylindrical member 3, an elastic support member 4 (elastic member) as an annular elastic member that connects the mounting member 2 and the cylindrical member 3 to each other, and the cylindrical member 3 are disposed in the cylindrical member 3. And a diaphragm 5 made of a rubber thin film as an elastic membrane member.

  The cylindrical member 3 is formed in a thin cylindrical shape, and the inner peripheral side thereof is connected to the mounting member 2 by the elastic support member 4, while the outer peripheral surface is connected to the elastic support member 4. Thus, a rubber layer 6 is provided, and the outer side thereof is covered with a casing (not shown). The casing is provided with a flange, and the flange is connected to a vibration source side such as an engine.

  The attachment member 2 has a substantially conical shape with a lower concavity, and is disposed substantially coaxially so that its lower end is located at the approximate center of the upper end opening of the tubular member 3. An elastic support member 4 is interposed between the side surface portion 2a and the inner peripheral surface of the cylindrical member 3 facing the outer periphery thereof. The mounting member 2 is provided with a screw hole 2b so as to be recessed from the upper end surface, and is fastened to a member on the vehicle body side by a bolt (not shown) screwed into the screw hole 2b. It has become.

  Further, a flange portion 2c is formed at the central portion in the axial direction of the mounting member 2 so as to project radially outward over the entire circumference thereof. On the surface of the flange portion 2c, the elastic portion is formed. A rubber layer 7 is provided so as to be connected to the support member 4. Of the rubber layer 7, the horizontal bulging portion 7 a that bulges radially outward on the outer peripheral surface of the flange portion 2 c is when a large horizontal displacement is input to the vibration isolator 1. The upper bulging portion 7b that bulges upwardly from the flange portion 2c receives a large displacement in the upward direction to the vibration isolator 1 while abutting against a casing (not shown) to restrict its displacement. In such a case, the displacement is restricted by contacting an unillustrated counterpart member.

  A mortar-shaped concave portion is formed on the inner peripheral side of the upper portion 4 a of the elastic support member 4, and the peripheral surface of the concave portion is attached to the tapered side surface portion 2 a of the mounting member 2. In addition, the elastic support member 4 is formed in a substantially truncated cone shape so as to expand radially outward from the entire circumference of the mounting member 2 and to extend obliquely downward. An outer peripheral surface of a certain lower portion 4 b is bonded to an inner peripheral surface of the cylindrical member 3. Thus, the lower part 4 b of the elastic support member 4 that is bonded and fixed to the inner periphery of the cylindrical member 3 has a cylindrical shape that opens downward, and its lower end is more predetermined than the lower end of the cylindrical member 3. It is positioned to be above the length.

  Then, a substantially disk-shaped rubber diaphragm 5 is superimposed on the lower end portion of the elastic support member 4 from below, and the lower end portion of the cylindrical member 3 is bent to the inner peripheral side, so that the diaphragm 5 is It is designed to be fixed. Thereby, the lower end opening of the elastic support member 4 is closed in a liquid-tight manner, and a cavity is formed therein.

  The diaphragm 5 includes a relatively thin central portion 5a (thin portion) formed in a substantially hat shape, and a relatively thick outer peripheral portion 5b (thick portion) surrounding the periphery. A metal reinforcing ring 8 is embedded in a portion sandwiched between the elastic support member 4 and the cylindrical member 3 on the outer peripheral side of 5b. The outer peripheral portion 5 b whose outer peripheral side is reinforced in this way is press-fitted into the lower end side inner periphery of the cylindrical member 3 from below, and is in an internally fitted state with the cylindrical member 3.

  Further, as described above, the cavity formed by the mounting member 2, the cylindrical member 3, the elastic support member 4 and the diaphragm 5 is filled with a buffer solution (liquid) such as ethylene glycol, and the liquid chamber F1 is formed. It is configured.

  A substantially annular projecting portion 5c is provided between the inner peripheral side of the outer peripheral portion 5b of the diaphragm 5, that is, between the diaphragm 5 and the central portion 5a. Thus, the protruding portion 5c forms an orifice passage S (flow passage) and a secondary liquid chamber F2 as will be described later.

  Next, the operation of the vibration isolator 1 having the above-described configuration will be described. When vibration is transmitted from the vibration source side to the vibration isolator 1, the elastic deformation of the elastic support member 4 is performed in the liquid chamber F1. As a result, the fluid pressure fluctuates, and the diaphragm 5 facing the fluid chamber F1 is vibrated. At this time, the diaphragm 5 has a central portion 5a formed thinner than the outer peripheral portion 5b, so that the central portion 5a vibrates more greatly than the outer peripheral portion 5b (shown by a dotted line in FIG. 1). .

  Then, with the deformation of the central portion 5a of the diaphragm 5, the buffer solution in the liquid chamber F1 moves in the region corresponding to the central portion 5a, that is, the region S surrounded by the protruding portion 5c. That is, when the central portion 5a is deformed downward, the buffer solution moves downward in the region S surrounded by the projecting portion 5b along with the deformation, while the central portion 5a is deformed upward. With the deformation, the buffer solution moves upward in the region S, and the input vibration is attenuated by the flow resistance of the buffer solution at that time.

  That is, the area surrounded by the protrusion 5c of the diaphragm 5 constitutes the orifice passage S (flow passage), and together with the central portion 5a of the diaphragm 5, the volume of the liquid chamber F1 accompanying the deformation of the central portion 5a. Thus, the secondary liquid chamber F2 that absorbs the fluctuations is also constituted.

  As described above, according to the present embodiment, the central portion 5a of the diaphragm 5 of the vibration isolator 1 is thinner than the outer peripheral portion 5b so that the central portion 5a can be easily deformed and protrudes so as to surround the central portion 5a. By providing the portion 5c, the vibration can be absorbed by the flow resistance accompanying the movement of the buffer solution when the central portion 5a is deformed. Therefore, as in the conventional structure, the liquid is used to absorb the low-frequency vibration. It is no longer necessary to partition the room up and down with a partition plate to provide an orifice passage, and the structure of the vibration isolator 1 can be simplified. Therefore, it is possible to reduce the number of parts and the assembly work, and to reduce the manufacturing cost of the vibration isolator 1.

-Modification of Embodiment 1-
In the first embodiment, as shown in FIG. 1, the inner diameter of the outer peripheral portion 5b of the diaphragm 5 is constant, that is, the protruding portion 5c has a substantially cylindrical shape with a constant inner diameter. However, as shown in FIG. You may make it the shape where the internal diameter of the (liquid chamber side) becomes smaller than the lower part.

  Specifically, a bulging portion 15d that bulges in the circumferential direction is formed in the upper portion of the protruding portion 15c provided in the diaphragm 15. By doing so, the cross-sectional area of the region S surrounded by the projecting portion 15c, that is, the cross-sectional area of the orifice passage can be reduced, and the inside of the orifice passage S moves along with the deformation of the central portion 15a of the diaphragm 15. A large flow resistance is generated by the buffer solution. Therefore, the resonance frequency of the liquid column resonance is lower than that of the first embodiment, and it is possible to absorb vibrations at a lower frequency. Here, in the case of this modification, the bulging part 15d constitutes the orifice passage S, and the space surrounded by the central part 15a, the lower part of the protruding part 15c and the outer peripheral part 15b constitutes the secondary liquid chamber F2. ing.

  Instead of forming the bulging portion 15d on the upper portion of the protruding portion 15c as described above, a plurality of projecting portions 15e, 15e,... May be provided as shown in FIG. Even with such a configuration, the resistance when the buffer solution moves in the orifice passage S is increased, and the frequency of the liquid column resonance in the orifice passage S can be lowered. Can absorb.

  Therefore, by providing the protruding portion 15c of the diaphragm 15 with the bulging portion 15d and the protruding portions 15e, 15e,... Bulging into the orifice passage S, it is possible to change the frequency range of vibration that can be damped. become.

(Embodiment 2)
FIG. 4 shows a cross-sectional structure of the vibration isolator 20 according to the second embodiment of the present invention. The vibration isolator 20 according to the second embodiment has substantially the same configuration as that of the modification of the first embodiment (see FIG. 2). Yes, only the structure of the diaphragm is different, so that the same parts are denoted by the same reference numerals and only the different parts will be described below.

  Specifically, in the second embodiment, a thick portion 25d (inner peripheral thick portion) is formed in the central portion 25a of the diaphragm 25, and the thick portion 25d is an outer peripheral portion 25b (outer peripheral thick portion). ) Is protruded inwardly of the liquid chamber F1 from the protruding portion 25c (outer peripheral thick portion) formed on the inner peripheral side. That is, the central portion 25a includes a substantially cylindrical thick portion 25d positioned at the central portion, a lower side of the outer peripheral end portion (outside of the liquid chamber), and an inner peripheral side of the outer peripheral portion 25b (protruding portion 25c). And a thin-walled portion 25e formed in a substantially ring shape in top view so that the upper half of the thick-walled portion 25d is located above the projecting portion 25c. It is designed to be positioned.

  Accordingly, as shown in FIG. 4, the main liquid chamber F1 formed in the elastic support member 4 and the thin wall portion are formed between the thick portion 25d of the central portion 25a and the protruding portion 25c of the outer peripheral portion 25b. A substantially ring-shaped flow passage S is formed in a top view that communicates with the secondary liquid chamber F2 formed by 25e and the outer peripheral portion 25b.

  In the vibration isolator 20 configured as described above, when vibration is transmitted from the vibration source side, in the main liquid chamber F1, as the elastic support member 4 is deformed, the hydraulic pressure of the buffer liquid is the same as in the first embodiment. Fluctuation occurs, causing the diaphragm 25 to vibrate. At this time, since the thin portion 25e of the central portion 25a of the diaphragm 25 is relatively greatly deformed, the buffer solution is caused to reciprocate between the main liquid chamber F1 and the sub liquid chamber F2 by the liquid column resonance in the flow path S. It will be distributed to. Thus, the vibration transmitted to the vibration isolator 20 is attenuated by the flow resistance when the buffer solution moves in the flow path S.

  As described above, in the present embodiment, the thick portion 25d is provided in the substantially central portion of the central portion 25a of the diaphragm 25, and the upper half of the thick portion 25d is positioned above the protruding portion 25c of the diaphragm 25. The auxiliary liquid chamber F2 can be formed by the thin wall portion 25e that connects the thick wall portion 25b and the outer peripheral portion 25b of the diaphragm 25, and the auxiliary liquid chamber is formed between the thick wall portion 25d and the protruding portion 25c. A flow path S that allows F2 and the main liquid chamber F1 to communicate with each other can be formed. That is, since the diaphragm 25 can form the sub liquid chamber F2 that absorbs the fluid pressure fluctuation in the main liquid chamber F1 and the flow path S that connects the main liquid chamber F1 and the sub liquid chamber F2, it has been conventionally necessary. The partition plate becomes unnecessary, and the configuration of the vibration isolator 20 can be simplified to reduce the cost.

  Further, the flow passage S is formed between the thick portion 25b and the outer peripheral portion 25b of the central portion 25a of the diaphragm 25, and the passage area is smaller than that of the configuration of the first embodiment. The frequency at which resonance occurs becomes lower, and it becomes possible to absorb lower frequency vibrations.

-Modification 1 of Embodiment 2
In the diaphragm 35 configured as in the second embodiment, as shown in FIG. 5, a substantially circular hole 35f (concave portion) is formed on the upper surface side of the thick portion 35d (inner peripheral thick portion) of the central portion 35a. You may make it provide.

  Specifically, the hole portion 35f is provided at the approximate center of the thick portion 35d so as to open toward the liquid chamber, and is formed so that the diameter thereof increases at the bottom. Thus, by providing the hole portion 35f in the thick portion 35d, the thickness of the portion of the thick portion 35d where the hole portion 35f is formed becomes thin, and deformation is relatively likely to occur.

  In the above-described configuration, when a relatively high frequency vibration is transmitted from the vibration source side to the vibration isolator 30, only a small fluid pressure fluctuation is generated in the main fluid chamber F1 due to the vibration. Due to the variation, the entire central portion 35a of the diaphragm 35 hardly deforms, and only the portion where the hole portion 35f of the thick portion 35d is formed slightly deforms. Then, due to the liquid column resonance in the hole 35f, the buffer solution in the main liquid chamber F1 moves through the hole 35f by the minute deformation, and the input vibration is attenuated by the flow resistance. Is done.

  That is, the hole 35f serves as an orifice passage and a sub liquid chamber different from the flow passage S constituted by the thick portion 35d and the protruding portion 35c and the sub liquid chamber F2 constituted by the thin portion 35e and the outer peripheral portion 35b. Will work.

  On the other hand, when the low frequency vibration is transmitted from the vibration source side to the vibration isolator 30, the central portion 35a of the diaphragm 35 is greatly deformed as in the above-described second embodiment. The buffer solution moves between the main liquid chamber F1 and the sub liquid chamber F2 by liquid column resonance, and the input vibration is attenuated by the flow resistance at that time.

  As described above, by providing the hole 35f in the thick portion 35d of the central portion 35a of the diaphragm 35, the vibration isolator 30 capable of attenuating not only low-frequency vibration but also high-frequency vibration can be simplified without a partition plate. It can be realized with a configuration.

  In addition to the hole portion 35f, another hole portion 35f 'having a different diameter may be provided in the thick portion 35d' of the central portion 35a 'of the diaphragm 35' as shown in FIG. By doing so, similar to the hole portion 35f, the hole portion 35f 'can obtain the same effect as the orifice passage, so that vibrations of different frequencies can be attenuated.

-Modification 2 of Embodiment 2
In the first modification of the second embodiment, the thick portion 35d of the central portion 35a of the diaphragm 35 is provided with a substantially circular hole portion 35f in a top view. However, as shown in FIG. A groove portion 45f (concave portion) having a substantially ring shape in a top view having substantially the same cross-sectional shape as the portion 35f is provided, and a portion of the thick portion 45d located on the inner peripheral side of the groove portion 45f is thicker than other portions. Thus, the main liquid chamber F1 may be protruded inward.

  Thus, by providing the groove 45f functioning as the orifice passage instead of the round hole, the passage area of the orifice passage can be increased, and higher-frequency vibrations can be damped efficiently. Moreover, the flow resistance of the buffer solution flowing into the ring-shaped groove 45f can be increased by increasing the thickness of the central part 45g of the thick-walled part 45d surrounded by the substantially ring-shaped groove 45f. The vibration can be absorbed more effectively.

  As shown in FIG. 8, a substantially circular hole 45h may be provided in the central portion 45g 'of the thick portion 45d'. By so doing, the hole 45h also functions as an orifice passage and a secondary liquid chamber in the same manner as the groove 45f, so that vibrations other than the frequencies damped by the groove 45f can also be attenuated.

—Modification 3 of Embodiment 2—
In the first modification of the second embodiment, a hole 35f is simply provided in the thick portion 35d of the central portion 35a of the diaphragm 35. As shown in FIG. 9, a buffer solution is provided in the hole 55f. You may make it provide the shielding part 56 which makes the distribution area of this small.

  Specifically, the shielding part 56 is integrally formed with the thick part 55d on the opening side of the hole 55f, and is arranged in a columnar shape so as to be positioned at the approximate center of the hole 55f in a top view. It consists of the part 56a and the connection part 56b which connects this columnar part 56a and the inner peripheral surface of the hole 55f. By providing such a shielding portion 56, the passage area of the opening portion of the hole portion 55f can be reduced, so that the flow resistance of the buffer solution that moves in the hole portion 55f with the input vibration is increased. Can do. Therefore, since the liquid column resonance occurs in the hole 55f due to the low-frequency vibration as compared with the case where the hole 55f is simply provided, the low-frequency vibration can be attenuated.

(Embodiment 3)
FIG. 10 shows a cross-sectional structure of a vibration isolator 60 according to Embodiment 3 of the present invention. The vibration isolator 60 according to Embodiment 3 has substantially the same configuration as that of the modification of Embodiment 1 (see FIG. 2). Yes, only the structure of the diaphragm is different. Therefore, the same reference numerals are given to the same parts, and only the different parts will be described below.

  Specifically, as in the first and second embodiments, a substantially ring-shaped protruding portion 65c is formed on the inner peripheral side of the outer peripheral portion 65a of the diaphragm 65 in a top view protruding toward the inside of the liquid chamber F1. Has been. A shielding portion 66 (shielding portion) is formed integrally with the opening end on the liquid chamber side so as to block a part of the opening end. As shown in FIG. 11, the shielding portion 66 includes a substantially rectangular parallelepiped thick portion 66 a disposed in the approximate center of the region S surrounded by the protruding portion 65 c in a top view, and the thick portion 66 a. It consists of connecting portions 66b, 66b,... That connect both ends to the protruding portion 65c, and is provided so as to close a part of the opening of the protruding portion 65c as described above, so that it is surrounded by the protruding portion 65c. This is a resistance when the buffer solution in the liquid chambers F1 and F2 moves in the region S, that is, in the orifice passage.

  Accordingly, the resistance received by the buffer solution moving in the region S surrounded by the projection 65c of the diaphragm 65, that is, in the orifice passage, is increased by the shielding portion 66, and vibration that causes liquid column resonance in the orifice passage S is caused. Since the frequency can be lowered, the lower frequency vibration transmitted to the vibration isolator 60 can be effectively damped.

(Other embodiments)
The present invention is not limited to the above-described embodiments, but includes other various embodiments. That is, in each of the above embodiments, the diaphragms 5, 15,... Are provided with the projecting portions 5c, 15c,... Projecting inward of the liquid chambers F, F1, but the present invention is not limited to this. , 15,... May be provided with a step between the outer peripheral portions 5 b, 15 b,... That are formed thick and the thin central portions 5 a, 15 a,.

  Further, in each of the above embodiments, the attachment member 2 is connected to the fixed body side such as the vehicle body, and the cylindrical member 3 is connected to the vibration source side such as the engine. The cylindrical member 3 may be connected to the fixed body side on the vibration source side.

  Furthermore, in the said Embodiment 2, as a modification, substantially circular shape which opens upwards in thick part 35d, 35d ', ... of center part 35a, 35a', ... of diaphragm 35, 35 ', ... One or two holes 35f, 35f 'are provided, or a substantially ring-shaped groove 45f is provided in a top view. However, the present invention is not limited to this, and three or more holes may be provided. However, the hole may have any shape.

It is sectional drawing which shows schematic structure of the vibration isolator which concerns on Embodiment 1 of this invention. FIG. 6 is a view corresponding to FIG. 1 according to a modification of the first embodiment. It is a cross-sectional view of the vibration isolator when a plurality of protrusions are provided on the inner periphery of the protrusion of the diaphragm in the modification of the first embodiment. FIG. 3 is a view corresponding to FIG. 1 according to a second embodiment. FIG. 10 is a view corresponding to FIG. 1 according to a first modification of the second embodiment. FIG. 9 is a view corresponding to FIG. 1 when a plurality of hole portions are provided in a thick portion at a central portion of a diaphragm in Modification 1 of Embodiment 2. FIG. 10 is a view corresponding to FIG. 1 according to a second modification of the second embodiment. FIG. 9 is a view corresponding to FIG. 1 when a hole is provided in the center of the thick portion in the second modification of the second embodiment. FIG. 10 is a view corresponding to FIG. 1 according to a third modification of the second embodiment. FIG. 6 is a view corresponding to FIG. 1 according to the third embodiment. It is the XI-XI sectional view taken on the line of FIG. It is sectional drawing which shows the structure of the conventional vibration isolator.

Explanation of symbols

F1 Main liquid chamber (liquid chamber)
F2 Sub liquid chamber S Flow passage, orifice passage 1, 10, 20, 30, 30 ', 40, 40', 50, 60 Vibration isolator 2 Mounting member 3 Tubular member (mounting member)
4 Elastic bearing members (elastic members)
5, 15, 25, 35, 35 ', 45, 45', 55, 65 Diaphragm (elastic membrane member)
5a, 15a, 25a, 35a, 35a ′, 65a Center portion (thin wall portion, inner peripheral thick wall portion)
5b, 15b, 25b, 35b, 65b Outer peripheral part (thick part, outer peripheral thick part)
5c, 15c, 25c, 35c, 65c Protruding part (thick part, outer peripheral thick part)
25d, 35d, 35d ', 55d Thick part at the center (inner peripheral thick part)
25e, 35e Thin part at the center (thin part)
35f, 35f ', 45h, 55f Hole (recess)
45f groove (concave)
45g, 45g 'Thick part central part 56, 66 Shielding part

Claims (4)

Two attachment members respectively connected to the support side and the supported side, an elastic member that elastically connects the two attachment members and relatively displaces both the attachment members by elastic deformation, and the inside of the elastic member is filled with liquid An elastic film member that partitions and forms a liquid chamber, and a liquid-filled vibration isolator comprising:
The elastic membrane member includes a thin portion for absorbing a change in volume of the liquid chamber caused by relative displacement of the two mounting members, and a thick portion provided so as to protrude at least around the thin portion toward the liquid chamber. And comprising
In the liquid chamber, there are formed a sub-liquid chamber that is surrounded by the thin-walled portion and the thick-walled portion, and whose volume changes with deformation of the thin-walled portion, and a fluid flow path to the sub-liquid chamber. A liquid-filled vibration isolator characterized by comprising: In claim 1,
The thick part of the elastic membrane member comprises at least a cylindrical outer peripheral thick part surrounding the flow passage, and a columnar inner peripheral thick part located on the liquid chamber side in the outer peripheral thick part. The flow path is formed between the meat part and the inner peripheral thick part,
The thin portion is formed in a substantially ring shape so as to connect the outer peripheral thick portion and the inner peripheral thick portion on the outer side of the liquid chamber. In claim 2,
The liquid filled type vibration damping device, wherein the inner peripheral thick wall portion is formed with at least one concave portion opening toward the inside of the liquid chamber. In claim 1,
A liquid-filled vibration damping device, wherein a shielding portion that closes a part of the opening end of the flow passage on the liquid chamber side is integrally formed with a thick portion of the elastic membrane member.