JP5969917B2 - Vibration isolator - Google Patents

Description

  The present invention relates to a liquid-filled vibration isolator that is used, for example, when a vibration generating unit such as an automobile engine is mounted on a vibration receiving unit such as a vehicle body.

  A problem that this type of vibration isolator has is that cavitation occurs in which a large number of bubbles are generated in the liquid when an excessively large shock load is input and an excessive negative pressure is generated in the liquid chamber. There is a problem that abnormal noise is generated when bubbles disappear as the hydraulic pressure increases.

  As a countermeasure, for example, as disclosed in Patent Document 1, a relief hole is formed in a fitting recess formed in the movable rubber film, while a closing projection that can be fitted in the fitting recess on the equilibrium chamber side of the movable rubber film. There is an anti-vibration device in which a contact plate in which a portion is formed is arranged, and the relief protrusion is closed by fitting the closing protrusion into the insertion recess.

  With this configuration, when an excessive negative pressure is generated in the pressure receiving liquid chamber, the movable rubber film is elastically deformed toward the pressure receiving liquid chamber, whereby the closing protrusion protrudes from the fitting recess and opens through the relief hole. The pressure receiving liquid chamber and the equilibrium chamber are communicated with each other. As a result, the fluid flows from the equilibrium chamber to the pressure receiving liquid chamber, thereby eliminating the excessive negative pressure in the pressure receiving liquid chamber and suppressing the occurrence of cavitation.

JP 2009-222192 A

  However, according to the above-mentioned Patent Document 1, the lower communication window formed at the bottom of the lower partition fitting, which is formed between the movable rubber film and the equilibrium chamber, has a large opening. For example, when the engine shake vibration is input, the liquid in the pressure receiving liquid chamber When the pressure increases, the movable rubber film is elastically deformed to the equilibrium chamber side and bulges from the opening of the lower communication window to the equilibrium chamber side. As a result, the substantial volume of the pressure receiving liquid chamber increases. For this reason, an increase in the hydraulic pressure in the pressure receiving liquid chamber is prevented, and the damping characteristics of the entire vibration isolating apparatus are lowered, and there is a possibility that desired vibration isolating characteristics cannot be obtained.

  Accordingly, an object of the present invention is to provide a vibration isolator capable of suppressing the occurrence of cavitation while maintaining the vibration isolating characteristics.

The vibration isolator of the present invention that achieves the above object includes a cylindrical first mounting member connected to one of a vibration generating unit and a vibration receiving unit, a second mounting member connected to the other, and the first An elastic body that elastically connects the first mounting member and the second mounting member; and a liquid chamber that is disposed inside the first mounting member and is formed inside the first mounting member. A partition member that divides the main liquid chamber on one side in the axial direction and the sub liquid chamber on the other side in the axial direction as a part of the wall surface, and is displaced according to a pressure difference between the main liquid chamber and the sub liquid chamber; And a movable plate having a through-hole penetrating in the axial direction, wherein the partition member defines a storage chamber for storing the movable plate, and the storage chamber and the main liquid the first communication hole of one section for communicating with the chamber, and is divided into a plurality of communicating the auxiliary liquid chamber and the storage chamber Is formed a second communication hole, the movable plate is the relative partition member, readily be deformable and in a direction toward the first communicating hole than a direction toward the second communicating hole, the auxiliary liquid of the partition member A closing portion that closes the through hole by contacting the movable plate is disposed on the chamber side.

  According to this, the movable plate accommodated in the storage chamber of the partition member that divides the liquid chamber into the main liquid chamber and the sub liquid chamber has the through hole, and the partition member is movable on the sub liquid chamber side of the partition member. By providing a closing part that closes the through hole by contacting the main liquid chamber, when a positive pressure is generated in the main liquid chamber, the movable plate is pressed against the closing part to maintain the closed state of the through hole. High hydraulic pressure can be achieved. Further, since the movable plate is configured not to be deformed in the direction toward the second communication hole that communicates the storage chamber and the sub liquid chamber, the volume change of the main liquid chamber occurs when a positive pressure is generated in the main liquid chamber. Can be kept small, and an increase in the fluid pressure in the main fluid chamber can be prevented from being suppressed. On the other hand, when the liquid pressure in the main liquid chamber decreases, the movable plate easily bulges and deforms toward the main liquid chamber to suppress the decrease in the liquid pressure in the main liquid chamber, and the movable plate penetrates away from the closing portion. The holes are opened, and the flow of liquid from the sub liquid chamber to the main liquid chamber is allowed, so that the decrease in the liquid pressure in the main liquid chamber is suppressed and the occurrence of cavitation is suppressed. Thereby, generation | occurrence | production of the abnormal sound by cavitation collapse | damping can be suppressed.

  Moreover, the opening area in the said partition member of the said 1st communicating hole may be larger than the opening area in the said partition member of the said 2nd communicating hole.

  Moreover, you may have the clearance gap which accept | permits the displacement of the outer-periphery edge part of the said movable plate between the outer peripheral range of the surface at the side of the said 1st communicating hole of the said movable plate, and a storage chamber inner surface.

  The through hole has an opening area on the second communication hole side larger than an opening area on the first communication hole side, and gradually decreases in diameter as it moves from the second communication hole side to the first communication hole side. It may be tapered.

  According to the present invention, when a positive pressure is generated in the main liquid chamber, the main liquid chamber can be increased in pressure, and an increase in the liquid pressure in the main liquid chamber can be prevented. Characteristics can be maintained. On the other hand, it is possible to provide a vibration isolator that suppresses the occurrence of cavitation when the liquid pressure in the main liquid chamber decreases.

It is sectional drawing of the vibration isolator concerning 1st Embodiment. It is a perspective view of a partition member. It is a top view of a partition member. It is sectional drawing which follows the AA line of FIG. It is a rear view of a partition member. It is operation | movement explanatory drawing of a vibration isolator. It is principal part sectional drawing of the vibration isolator concerning 2nd Embodiment. It is principal part sectional drawing of the vibration isolator concerning 3rd Embodiment.

(First embodiment)
A first embodiment of the present invention will be described with reference to FIGS.

  As shown in FIG. 1, the vibration isolator 10 includes a cylindrical first mounting member 11 connected to one of the vibration generating unit and the vibration receiving unit, and a second mounting member 12 connected to the other, An elastic body 13 that elastically connects the first mounting member 11 and the second mounting member 12, and a liquid chamber 16 in which the opening of the first mounting member 11 is closed and liquid can be sealed in the first mounting member 11. A diaphragm 14 to be formed, and a partition member 15 disposed inside the first mounting member 11 and partitioning the liquid chamber 16 from the main liquid chamber 16a and the sub liquid chamber 16b are provided.

  These members are provided coaxially with the central axis O. The liquid chamber 16 is filled with a liquid such as ethylene glycol, water, or silicone oil. When the vibration isolator 10 is mounted on an automobile or the like as an engine mount, for example, the second mounting member 12 is connected to an engine that is a vibration generating unit, while the first mounting member 11 receives vibration through a bracket or the like. By being connected to the vehicle body that is a part, the vibration of the engine is prevented from being transmitted to the vehicle body.

  The first mounting member 11 includes a first cylindrical portion 11a on one axial end side, a second cylindrical portion 11b on the other axial end side, and a small diameter step portion connecting the first cylindrical portion 11a and the second cylindrical portion 11b. 11c, and the first cylinder part 11a, the second cylinder part 11b, and the step part 11c are arranged coaxially with the central axis O and are integrally formed.

  The second mounting member 12 is disposed outward in the central axis O direction from one axial end of the first mounting member 11. Then, the opening on the one end side in the axial direction of the first mounting member 11 is closed in a liquid-tight state by the elastic body 13, and the opening portion on the other end in the axial direction of the first mounting member 11 is closed in a liquid-tight state by the diaphragm 14. Thus, a liquid chamber 16 in which a liquid can be sealed is formed in the first mounting member 11.

  The elastic body 13 is made of, for example, a rubber material, and protrudes outward from the inner circumferential surface at one axial end portion of the first mounting member 11 toward the center axis O direction, and decreases in diameter as it moves outward in the center axis O direction. A substantially frustoconical main body portion 13a, and a covering portion 13b extending from the main body portion 13a toward the other axial end along the inner peripheral surface of the first mounting member 11. The main body portion 13a and the covering portion 13b are integrally formed. The covering portion 13b is vulcanized and bonded to the inner peripheral surface of the first mounting member 11, and the inner peripheral surface of the first mounting member 11 is covered with the elastic body 13 over the entire area.

  The partition member 15 disposed inside the first mounting member 11 will be described with reference to FIGS. 2 to 5. 2 is a perspective view of the partition member 15, FIG. 3 is a plan view of the partition member 15, FIG. 4 is a cross-sectional view taken along line AA of FIG. 3, and FIG. 5 is a rear view of the partition member.

  As shown in FIG. 2, the partition member 15 is made of, for example, an aluminum alloy or resin, and a disk-shaped first partition plate 21 and second partition plate 22 that are opposed to each other are integrally formed by a peripheral wall 27.

  As shown in FIG. 1, the outer surface 21b on the one axial side of the first partition plate 21 faces the main liquid chamber 16a side, and the first partition plate 21 forms a part of the partition wall of the main liquid chamber 16a. doing. Further, the outer surface 22b on the other axial side of the second partition plate 22 faces the sub liquid chamber 16b side, and the second partition plate 22 forms a part of the partition wall of the sub liquid chamber 16b.

  As shown in FIG. 4, the first partition plate 21 and the second partition plate 22 are connected by a peripheral wall 27 to accommodate the movable plate 18 between the first partition plate 21 and the second partition plate 22. A storage chamber 29 is defined by being surrounded by the inner surface 21 a of the first partition plate 21, the inner surface 22 a of the second partition plate 22, and the peripheral wall 27. An opening 28 communicating with the storage chamber 29 is formed in the peripheral wall 27, and the movable plate 18 is inserted into the movable plate accommodating portion 29 from the opening 28.

  The first partition plate 21 is formed with a first communication hole 23 having a circular shape in plan view that penetrates the first partition plate 21 in the axial direction, and the storage chamber 29, the main liquid chamber 16 a, and the like are formed through the first communication hole 23. Communicate.

  As shown in FIGS. 2 and 3, the first communication hole 23 includes a plurality of ribs 23 b extending inward in the radial direction on the inner peripheral surface 23 a of the first communication hole 23, in the present embodiment. Projected at substantially equal intervals in the circumferential direction. The ribs 23b prevent the movable plate 18 from coming out of the storage chamber 29 toward the main liquid chamber 16a. Further, the protruding amount of each rib 23b from the inner peripheral surface 23a of the first communication hole 23 toward the radially inner side is smaller than the radius of the inner peripheral surface 23a, for example, half the radius of the inner peripheral surface 23a of the first communication hole 23. It is about.

  The second partition plate 22 is formed with a second communication hole 24 having a circular shape in plan view that penetrates the second partition plate 22 in the axial direction. The second communication hole 24 allows the storage chamber 29 and the auxiliary liquid chamber 16b to be connected. Communicate.

  On the inner peripheral surface 24a of the second communication hole 24, a plurality of bridging portions 24b that connect portions facing each other in the radial direction of the inner peripheral surface 24a protrude, and in the present embodiment, the two bridging portions 24b are centered. The position is shifted by 90 ° about the axis O. The circumferential width of the bridging portion 24b is formed wider than the width of the rib 23b, and the bridging portion 24b is configured to have a larger contact area with the movable plate 18 than the rib 23b.

  A planar closing portion 25 is formed on the central axis O where the bridging portions 24b intersect. As a result, the closing portion 25 supported by the partition member 15 is disposed on the side of the sub liquid chamber 16 a of the movable plate 18.

  Thus, the main liquid chamber 16a and the sub liquid chamber 16b are communicated with each other through the storage chamber 20, the first communication hole 23, and the second communication hole 24. The opening area of the first communication hole 23 on the main liquid chamber 16a side is set larger than the opening area of the second communication hole 24 on the sub liquid chamber 16b side.

  As shown in FIG. 2, the partition member 15 is provided with an orifice separately from the first communication passage 23, the second communication passage 24, and the housing portion 29 as a passage that connects the main liquid chamber 16 a and the sub liquid chamber 16 b. A passage 17 is formed.

  The movable plate 18 is made of, for example, a rubber material. The movable plate 18 has a plate shape substantially similar to the shape of the housing portion 29 and is formed in a substantially rectangular shape in plan view having a size covering the first communication hole 23 and the second communication hole 24 over the entire area.

  The outer peripheral edge portion 18a of the movable plate 18 can contact the inner surface 21a of the first partition plate 21 and the inner surface 22a of the second partition plate 22, and a plurality of spherical convex portions 18d are formed on the upper surface 18b and the lower surface 18c. Thus, the collision sound generated when the movable plate 18 vibrates and comes into contact with the first partition plate 21 and the second partition plate 22 is reduced.

  Furthermore, the movable plate 18 is formed to a size that covers the first communication hole 23 and the second communication hole 24 formed in the first partition plate 21 and the second partition plate 22 over the entire area, and vibration with a large amplitude is generated. When generated, the vibration is prevented by the orifice passage 17 without being communicated via the peripheral portions of the main liquid chamber 16a and the sub liquid chamber 16b. A through-hole 19 having a circular cross section that penetrates from the upper surface 18 b to the lower surface 18 c is formed in the central portion on the central axis O of the movable plate 18 so as to correspond to the closing portion 25.

  In the vibration isolator 10 configured as described above, the opening area of the first communication hole 23 on the main liquid chamber 16a side is set larger than the opening area of the second communication hole 24 on the sub liquid chamber 16b side. The movable plate 18 is less likely to deform toward the sub liquid chamber 16b than the main liquid chamber 16a, and the movable plate 18 protrudes toward the main liquid chamber 16a compared to the sub liquid chamber 16b. It is easy to be displaced or elastically deformed, and by this deformation, the lower surface 18c is separated from the closing portion 25, and the closing of the through hole 19 is released. Further, in a state where no negative pressure is generated in the main liquid chamber 16 a, the through hole 19 of the movable plate 18 is kept closed by the closing portion 25.

  Further, in a state where no negative pressure is generated in the main liquid chamber 16 a, the through hole 19 of the movable plate 18 is maintained in a closed state by the closing portion 25. For example, when a positive pressure is generated in the main liquid chamber 16a, the movable plate 18 is pressed against the closing portion 25 formed on the side of the sub liquid chamber 16b, so that the closed state of the through hole 19 is stabilized and the closing portion 25 is stabilized. Reliability due to the blockage of the through-hole 19 due to can be ensured. That is, the main fluid chamber 16a can have a high hydraulic pressure, and a damping characteristic at a high load can be obtained.

  The orifice passage 17 is adjusted so that the vibration-proofing effect based on the fluid flow action can be exhibited, for example, against vibrations in a low frequency range corresponding to engine shake. In addition, the natural frequency is such that an anti-vibration effect based on the hydraulic pressure absorption effect of the main liquid chamber 16a due to the elastic deformation of the movable plate 18 is effectively exerted against vibration in the middle frequency range corresponding to idling vibration or the like. It has been adjusted.

  Accordingly, absorption of pressure change in the main liquid chamber 16a due to elastic deformation of the movable plate 18 and pressure leakage through the through hole 19 are suppressed, and an effective pressure difference is generated between the main liquid chamber 16a and the sub liquid chamber 16b. As a result, a sufficient amount of flow through the orifice passage 17 is ensured. As a result, the vibration isolation effect due to the resonance action of the fluid flowing through the orifice passage 17 is effectively exhibited.

  Next, the operation and effect of the vibration isolator 10 configured as described above will be described.

  In the vibration isolator 10 configured as described above, a vibration having a minute amplitude (for example, engine idling vibration) acts on the first mounting member 11 or the second mounting member 12, and the hydraulic pressure in the main fluid chamber 16a is increased. Is changed, the movable plate 18 is displaced or elastically deformed between the inner surface 21a of the first partition plate 21 and the inner surface 22a of the second partition plate 22 to absorb and attenuate the vibration.

  Note that when the pressure fluctuation in the main liquid chamber 16a is absorbed by the elastic deformation of the movable plate 18, the pressure fluctuation generated in the main liquid chamber 16a is extremely small. Therefore, the change in which the movable plate 18 is separated from the closing portion 25. It is configured that a negative pressure large enough to apply the pressure hardly occurs in the main liquid chamber 16a. Thereby, the through-hole 19 is maintained in the state closed by the closing part 25, and the hydraulic pressure absorption effect is stably obtained.

  In addition, when a shocking heavy load is input to the vibration isolator 10 when overcoming a step or the like while the automobile is running, a high hydraulic pressure is generated in the main liquid chamber 16a, and the movable plate 18 is moved to the second partition plate. The through-hole 19 is closed by the closing portion 25 by being pressed by the inner surface 22a of the 22, so that a damping characteristic at high load is obtained. Here, since the opening area of the first communication hole 23 on the main liquid chamber 16a side is set larger than the opening area of the second communication hole 24 on the sub liquid chamber 16b side, it is compared with the main liquid chamber 16a side. The movable plate 18 is unlikely to be deformed toward the sub liquid chamber 16b, and therefore when the positive pressure is generated in the main liquid chamber 16a, the volume of the main liquid chamber 16a is unlikely to increase due to the elastic deformation of the movable plate 18, The liquid pressure in the main liquid chamber 16a is kept high. That is, high attenuation characteristics can be obtained.

  A case where an excessive negative pressure is generated in the main liquid chamber 16a will be described with reference to FIG.

  When the pressure in the main liquid chamber 16a decreases, the movable plate 18 is sucked toward the main liquid chamber 16a due to the relative pressure difference between the main liquid chamber 16a and the sub liquid chamber 16b, and in particular, the first communication hole on the main liquid chamber 16a side. 23 is formed to be larger than the opening area on the side of the sub liquid chamber 16B, so that it is easily swelled and deformed toward the main liquid chamber 16a as compared with the side of the sub liquid chamber 16b. Suppresses the decrease in hydraulic pressure.

  On the other hand, with the elastic deformation of the movable plate 18, the lower surface 18 c is separated from the closing portion 25 and the through hole 19 is opened. As a result, the main liquid chamber 16a and the sub liquid chamber 16b communicate with each other through the first communication hole 23, the through hole 19, and the second communication hole 24, and the flow of liquid from the sub liquid chamber 16b to the main liquid chamber 16a is allowed. The decrease in hydraulic pressure in the main liquid chamber 16a is suppressed, and the occurrence of cavitation can be suppressed.

  Furthermore, in order for the movable plate 18 to easily bulge and deform toward the main liquid chamber 16a, the space α defined between the surface of the movable plate 18 on the side of the secondary liquid chamber 16b, that is, the lower surface 18c and the storage chamber 19 is formed. Thus, the fluidity of the liquid flowing from the sub liquid chamber 16b through the second communication hole 24 can be improved, and the occurrence of cavitation can be suppressed quickly. In addition, such an effect can be achieved without disposing a closing projection to be inserted into a relief hole formed on the movable plate or providing a valve, thereby reducing the cost and the desired prevention. The generation of abnormal noise due to the collapse of cavitation can be suppressed while maintaining the vibration characteristics.

  In the above embodiment, the through-hole 19 having a circular cross section is formed in the movable plate 18. However, for example, the through-hole 19 may be formed by slit-shaped cuts, and small holes are provided at both ends of the cut. As a result, the local distortion in the cutting is relaxed and the durability of the cutting is improved.

  The through-hole 19 can also be formed in a tapered shape in which the opening area on the lower surface 18c side is larger than the opening area on the upper surface 18b side and gradually decreases in diameter as it moves from the lower surface 18c side to the upper surface 18b side. According to this, when the liquid pressure in the main liquid chamber 16a becomes high, it is difficult for liquid to escape from the through hole 19 to the sub liquid chamber 16b side, and the positive pressure in the main liquid chamber 16 is more reliably ensured. On the other hand, when the main liquid chamber 16a has a negative pressure, it is easy to flow out from the sub liquid chamber 16b side to the main liquid chamber 16a side, and cavitation can be more smoothly suppressed. In other words, the flow amount from the sub liquid chamber 16b side to the main liquid chamber 16a side is set larger than the flow amount from the main liquid chamber 16a side to the sub liquid chamber 16b side, so that a leak effect, that is, cavitation occurs. Can be suppressed.

(Second Embodiment)
A second embodiment of the present invention will be described with reference to FIG.

  FIG. 7 is a cross-sectional view of a main part of the vibration isolator according to the present embodiment. In FIG. 7, parts corresponding to those in FIGS. 1 to 5 are denoted by the same reference numerals, and detailed description thereof is omitted, and the partition member 15 different from the first embodiment will be mainly described.

  The partition member 15 disposed inside the first mounting member 11 includes a disk-shaped first partition plate 21 and a second partition plate 22 that face each other in the same manner as in the first embodiment. The outer surface 21b of the second partition plate 22 faces the side of the main liquid chamber 16a, the outer surface 22b of the second partition plate 22 faces the side of the sub liquid chamber 16b, and the first partition plate 21 and the second partition connected by the peripheral wall 27. A storage chamber 29 is defined between the plate 22 and the plate 22.

  The first partition plate 21 is formed with a first communication hole 23 having a circular shape in plan view that penetrates in the axial direction, and the storage chamber 29 and the main liquid chamber 16 a communicate with each other through the first communication hole 23. On the inner peripheral surface 23a of the first communication hole 23, a plurality of ribs 23b that connect portions facing each other in the radial direction of the inner peripheral surface 23a are disposed so as to protrude.

  The second partition plate 22 is formed with a second communication hole 24 having a circular shape in plan view that penetrates in the axial direction, and the storage chamber 29 and the auxiliary liquid chamber 16 b communicate with each other through the second communication hole 24. On the inner peripheral surface 24a of the second communication hole 24, a plurality of bridging portions 24b that connect portions facing each other in the radial direction of the inner peripheral surface 24a are disposed so as to protrude. A planar closing portion 25 is formed in the bridging portion 24b adjacent to the inner peripheral surface 24a.

  The movable plate 18 has a shape substantially similar to the shape of the movable plate housing portion 29, and a plurality of spherical convex portions 18d are formed on the upper surface 18b and the lower surface 18c, and the outer peripheral edge portion 18a from the center side in the outer peripheral area of the upper surface 18b. A tapered inclined surface 18e that gradually separates from the inner surface 21a of the first partition plate 21 as it moves to the side is formed, and an annular thin portion 18f is formed along the outer peripheral edge portion 18a. A through hole 19 is formed in the thin portion 18f so as to face the closing portion 25 formed in the bridging portion 24b.

  In the vibration isolator 10 configured as described above, a thin portion 18 f having an annular inclined surface 18 e is formed along the outer peripheral edge portion 18 a of the movable plate 18, and the lower surface 18 c contacts the inner surface 22 a of the second partition plate 22. On the other hand, the central range of the upper surface 18b can contact the inner surface 21a of the first partition plate 21, and the central axis O direction is between the inclined surface 18e of the thin portion 18f and the inner surface 21a of the first partition plate 21. The gap δ is formed. Accordingly, the outer peripheral edge portion 18a including the thin wall portion 18f, that is, the outer peripheral range is configured to be easily displaced or elastically deformed so as to rise toward the main liquid chamber 16a side as compared with the sub liquid chamber 16b side. Due to this elastic deformation, the lower surface 18c is separated from the closing portion 25, and the closing of the through hole 19 is released. Further, in a state where no negative pressure is generated in the main liquid chamber 16 a, the through hole 19 is maintained in a closed state by the closing portion 25.

  In the vibration isolator 10 configured as described above, when a positive pressure is generated in the main liquid chamber 16a, the movable plate 18 is hardly elastically deformed toward the sub liquid chamber 16b, and depending on the elastic deformation of the movable plate 18, The volume of the main liquid chamber 16a hardly increases, and the liquid pressure in the main liquid chamber 16a is maintained high. That is, high attenuation characteristics can be obtained. On the other hand, when an excessively large negative pressure is generated in the main liquid chamber 16a due to the input of a shocking large load, the movable plate 18 is caused by the relative pressure difference between the main liquid chamber 16a and the sub liquid chamber 16b. Since the gap δ is formed between the inclined surface 18e and the inner surface 21a of the first partition plate 21, the main liquid chamber 16a is easily deformed toward the main liquid chamber 16a. While the liquid pressure drop in the chamber 15a is suppressed, the lower surface 18c is separated from the closing portion 25 as the movable plate 18 is deformed, and the through hole 19 is opened. As a result, the main liquid chamber 16a and the sub liquid chamber 16b communicate with each other through the through-hole 19, and the flow of liquid from the sub liquid chamber 16b to the main liquid chamber 16a is allowed, and a decrease in the liquid pressure in the main liquid chamber 16a is suppressed. Therefore, the occurrence of cavitation can be suppressed.

(Third embodiment)
A third embodiment of the present invention will be described with reference to FIG. FIG. 8 is a cross-sectional view of a main part of the vibration isolator according to the present embodiment. In FIG. 8, parts corresponding to those in FIGS. 1 to 5 are denoted by the same reference numerals, and detailed description thereof is omitted, and different parts are mainly described.

  The inner surface 21a of the first partition plate 21 is formed with a tapered inclined surface 21c that gradually separates from the inner surface 22a of the second partition plate 22 in the direction of the central axis O as it moves from the center side to the outer peripheral edge side in the outer peripheral range.

  In the vibration isolator 10 configured as described above, the lower surface 18c of the movable plate 18 can contact the inner surface 22a of the second partition plate 22, while the central range of the upper surface 18b is on the inner surface 21a of the first partition plate 21. Since a gap δ in the direction of the central axis O is formed between the outer peripheral range of the upper surface 18b and the inclined surface 21c of the first partition plate 21, the outer peripheral edge portion 18a has an outer peripheral edge portion 18a as compared with the sub liquid chamber 16b side. It is easy to be displaced or elastically deformed so as to rise toward the main liquid chamber 16a side, and this deformation causes the lower surface 18c to move away from the closing portion 25 and the closure of the through hole 19 is released. Further, in a state where no negative pressure is generated in the main liquid chamber 16 a, the through hole 19 is maintained in a closed state by the closing portion 25.

  In the vibration isolator 10 configured as described above, when a positive pressure is generated in the main liquid chamber 16a, the movable plate 18 is hardly elastically deformed toward the sub liquid chamber 16b, and depending on the elastic deformation of the movable plate 18, The volume of the main liquid chamber 16a hardly increases, and the liquid pressure in the main liquid chamber 16a is maintained high. That is, high attenuation characteristics can be obtained. On the other hand, when an excessively large negative pressure is generated in the main liquid chamber 16a due to the input of a shocking large load, the movable plate 18 is caused by the relative pressure difference between the main liquid chamber 16a and the sub liquid chamber 16b. Since the gap δ in the direction of the central axis O is formed between the outer peripheral area of the upper surface 18b of the movable plate 18 and the inclined surface 21c of the first partition plate 21 in particular, the gap δ in the central axis O direction is formed. The outer peripheral edge portion 18a is easily deformed toward the main liquid chamber 16a side to suppress a decrease in the liquid pressure in the main liquid chamber 15a, and the lower surface 18c is separated from the closing portion 25 as the movable plate 18 is deformed. The through hole 19 is opened. As a result, the main liquid chamber 16a and the sub liquid chamber 16b communicate with each other through the through-hole 19, and the flow of liquid from the sub liquid chamber 16b to the main liquid chamber 16a is allowed, and a decrease in the liquid pressure in the main liquid chamber 16a is suppressed. Therefore, the occurrence of cavitation can be suppressed.

  The present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the spirit of the invention. For example, in the present embodiment, the orifice passage 17 is provided on the peripheral wall 27 of the partition member 15 along the central axis O. However, the orifice passage extends along the circumferential direction of the peripheral wall 27 and one end of the orifice passage. It is also possible to provide a long passage for the orifice 19 by providing a passage that communicates with the main liquid chamber 16a and a passage that communicates the other end of the orifice passage and the sub liquid chamber 16b.

  Furthermore, although the partition member 15 is configured by integrally forming the first partition member 21 and the second partition plate 22, the first partition member 21 and the second partition member 22 may be formed separately.

  The same configuration can also be adopted in a so-called adhesive type membrane in which the outer peripheral edge portion 18a of the movable plate 18 is bonded to the inner surface 21a of the first partition plate 21, the inner surface 22a of the second partition plate 22, or the like.

DESCRIPTION OF SYMBOLS 10 ... Vibration isolator 11 ... 1st attachment member 12 ... 2nd attachment member 13 ... Elastic body 14 ... Diaphragm 15 ... Partition member 16 ... Liquid chamber 16a ... Main liquid chamber 16b ... Sub liquid chamber 17 ... Orifice passage 18 :: Movable plate 19 ... Through hole 21 ... First partition plate 21a ... Inner surface 21b ::: Outer surface 22 ... 2nd partition plate 22a ... Inner surface 22b ... Outer surface 23 ... 1st communicating hole 23a ... Inner peripheral surface 24 ... 2nd communicating hole 25 ... Closure part 29 ... Storage chamber

Claims (4)

A cylindrical first mounting member coupled to either one of the vibration generating unit and the vibration receiving unit, and a second mounting member coupled to the other;
An elastic body that elastically connects the first mounting member and the second mounting member;
A liquid chamber disposed inside the first mounting member and formed inside the first mounting member;
A partition member that divides the main liquid chamber on one side in the axial direction and the sub liquid chamber on the other side in the axial direction with the elastic body as a part of the wall surface;
A movable plate that is displaced according to a pressure difference between the main liquid chamber and the sub liquid chamber and has a through hole penetrating in the axial direction;
In the vibration isolator with
In the partition member, a storage chamber for storing the movable plate is defined, a first communication hole of a section communicating the storage chamber and the main liquid chamber, and the storage chamber and the sub liquid chamber. A plurality of second communication holes that communicate with each other are formed,
The movable plate can be easily deformed with respect to the partition member in a direction toward the first communication hole rather than a direction toward the second communication hole,
A vibration isolator, wherein a closing portion that closes the through hole by being in contact with the movable plate is disposed on the side of the secondary liquid chamber of the partition member.   2. The vibration isolator according to claim 1, wherein an opening area of the first communication hole in the partition member is larger than an opening area of the second communication hole in the partition member.   2. The gap according to claim 1, wherein a gap allowing displacement of an outer peripheral edge portion of the movable plate is provided between an outer peripheral range of a surface of the movable plate on the first communication hole side and an inner surface of the accommodation chamber. Anti-vibration device.   The through hole has a taper that has an opening area on the second communication hole side larger than an opening area on the first communication hole side and that gradually decreases in diameter as it moves from the second communication hole side to the first communication hole side. The vibration isolator according to any one of claims 1 to 3, wherein the vibration isolator is in a shape.

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