Liquid-filled vibration isolation device

Abstract

To provide a liquid sealed type vibration control device capable of miniaturizing a negative pressure relief valve.SOLUTION: A projecting portion 27 projecting from a second partition plate 26 closes a communication hole 32 of a movable plate 30. The movable plate 30 is displaced (deformed) to a first partition plate 23 side in negatively pressurizing a first liquid chamber 17, and a liquid flows into the first liquid chamber 17 from a second liquid chamber 18 via the communication hole 32 in separating the projecting portion 27 and the movable plate 30 from each other. Thus, a negative pressure relief valve using the projecting portion 27 and the movable plate 30 is configured. Radial movement of the movable plate 30 to the projecting portion 27 can be restricted by bringing a restriction portion (inclined inner surface 34, second side convex portion 36) of the movable plate 30 into contact with an outer peripheral surface of the projecting portion 27. As it is unnecessary to hold the outer peripheral portion of the movable plate 30 with the first partition plate 23 and the second partition plate 26 so as to position the movable plate 30, the negative pressure relief valve can be miniaturized.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a hydraulic vibration isolating device, and more particularly to a hydraulic vibration isolating device that allows a negative pressure relief valve to be made compact. [Background technology]

[0002] One example of a known vibration-damping device that supports a vibration source such as an engine on a vehicle body (support side) is the hydraulic vibration-damping device disclosed in Patent Document 1. The hydraulic vibration-damping device disclosed in Patent Document 1 has a liquid chamber formed inside that is divided into a first liquid chamber and a second liquid chamber by a partition. The partition includes a first partition plate facing the first liquid chamber, a second partition plate facing the second liquid chamber, and a movable plate made of an elastic material whose outer periphery is sandwiched between the first partition plate and the second partition plate.

[0003] Furthermore, Patent Document 1 describes that a short-circuit path including a communication hole formed through the movable plate is switched between a connected state and a blocked state by a negative pressure relief valve. The negative pressure relief valve displaces (deforms) a part of the movable plate toward the first partition plate when the first fluid chamber reaches a predetermined negative pressure state, thereby connecting the short-circuit path, and basically presses the movable plate against the second partition plate in other cases, thereby blocking the short-circuit path. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2012-215214 Summary of the Invention [Problem to be solved by the invention]

[0005] However, in the prior art, the positioning of the movable plate, which is displaceable to switch the vacuum relief valve between a communicating state and a blocked state, is achieved by clamping the outer periphery of the movable plate between a first partition plate and a second partition plate, which poses a problem in that it is difficult to make the vacuum relief valve compact.

[0006] SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and an object of the present invention is to provide a liquid-filled vibration-damping device that can make a negative pressure relief valve more compact. [Means for solving the problem]

[0007] In order to achieve this object, the present invention provides a liquid-filled vibration-damping device comprising a first member and a cylindrical second member, an elastic vibration-damping base that connects the first member and the second member, an elastic diaphragm that is attached to the second member and forms a liquid chamber between the elastic diaphragm and the vibration-damping base and in which a liquid is sealed, a partition that separates the liquid chamber into a first liquid chamber and a second liquid chamber, and an orifice that connects the first liquid chamber and the second liquid chamber, wherein the partition comprises a first partition plate that has a first through-hole formed through it in the plate thickness direction and faces the first liquid chamber, and a second through-hole formed through it in the plate thickness direction. the second partition plate is formed of a resin and faces the second liquid chamber; and the movable plate is arranged between the first partition plate and the second partition plate and is made of an elastic material and has a communication hole formed through it in the radial center, the first partition plate contacts the movable plate to allow communication between the communication hole and the first through hole, the second partition plate has a protruding portion that protrudes toward the first partition plate and sandwiches the movable plate between itself and the first partition plate to close the communication hole when no vibration is input, and the movable plate has a restricting portion that contacts the outer peripheral surface of the protruding portion and restricts radial movement of the movable plate relative to the protruding portion. [Effects of the Invention]

[0008] According to the liquid-filled vibration-damping device of claim 1, the first partition plate and the movable plate are in contact with each other so that the communication hole and the first through hole can communicate with each other. When vibration is not input, A protruding portion protruding from the second partition plate toward the first partition plate the movable plate is sandwiched in the plate thickness direction only between the protruding portion of the first partition plate and the base portion provided at a position opposite to the protruding portion in the plate thickness direction, Communication hole but Closed Escape. As a result of negative pressure in the first fluid chamber due to vibration input, (When the first fluid chamber reaches a certain negative pressure) When the movable plate is displaced (deformed) toward the first partition plate and the protrusion separates from the movable plate, liquid flows from the second liquid chamber into the first liquid chamber through the communication hole. In this way, a negative pressure relief valve is formed using the protrusion and the movable plate.

[0009] By bringing the restricting portion of the movable plate into contact with the outer peripheral surface of the protrusion that protrudes from the second partition plate to form the negative pressure relief valve, radial movement of the movable plate relative to the protrusion of the second partition plate can be restricted. Since there is no need to sandwich the outer peripheral portion of the movable plate between the first and second partition plates to position the movable plate, the negative pressure relief valve can be made more compact.

[0010] The liquid-filled vibration damping device of claim 2 achieves the following effect in addition to the effect achieved by the liquid-filled vibration damping device of claim 1. The outer peripheral surface of the protrusion has an inclined outer surface that inclines radially inward as it approaches the first partition plate, and the inner peripheral surface of the communicating hole has an inclined inner surface that inclines radially inward as it approaches the first partition plate. The inclined inner surface forms a restricting portion by contacting the inclined outer surface over the entire circumference, and this contact closes the communicating hole. In this way, the inclined outer surface and the inclined inner surface for closing the communicating hole are inclined in the same way, making it easier to position the movable plate radially relative to the protrusion.

[0011] According to the liquid-filled vibration-damping device of claim 3, The first partition plate and the movable plate come into contact to allow communication between the communication hole and the first through-hole, and a protrusion protruding from the second partition plate toward the first partition plate sandwiches the movable plate between itself and the first partition plate to block the communication hole when no vibration is input. When vibration input causes negative pressure in the first liquid chamber, the movable plate is displaced (deformed) toward the first partition plate, and the protrusion and the movable plate separate, allowing liquid to flow from the second liquid chamber into the first liquid chamber through the communication hole. In this way, a negative pressure relief valve is formed using the protrusion and the movable plate. By bringing the restricting portion of the movable plate into contact with the outer peripheral surface of the protrusion that protrudes from the second partition plate to form the negative pressure relief valve, radial movement of the movable plate relative to the protrusion of the second partition plate can be restricted. Since there is no need to sandwich the outer peripheral portion of the movable plate between the first and second partition plates to position the movable plate, the negative pressure relief valve can be made more compact. The movable plate has a plurality of second-side protrusions that protrude from the periphery of the communication hole toward the second partition plate. The plurality of second-side protrusions contact the outer peripheral surface of the protrusions to form a restricting portion, making it easier to position the movable plate radially relative to the protrusions. Because the plurality of second-side protrusions are arranged at intervals in the circumferential direction, it is difficult for the second-side protrusions to block the flow path formed between the movable plate and the protrusions when negative pressure is applied to the main liquid chamber. As a result, even when the second-side protrusions are provided, the liquid flow in the flow path that is opened by the negative pressure relief valve when negative pressure is applied to the main liquid chamber can be smooth.

[0012] The liquid-filled vibration damping device of claim 4 achieves the following effect in addition to the effect achieved by the liquid-filled vibration damping device of claim 3. The movable plate has a plurality of first side convex portions that protrude at intervals in the circumferential direction. Since the first through-hole is located radially outward of the first side convex portions that are lined up in the circumferential direction, even when the plurality of first side convex portions come into contact with the first partition plate, the first partition plate and the movable plate are separated in part in the circumferential direction, making it possible to easily communicate the communication hole with the first through-hole.

[0013] Furthermore, since the multiple first-side protrusions protrude from the side of the movable plate opposite to the portion where the multiple second-side protrusions are arranged in the circumferential direction, even if the movable plate is turned over, the original second-side protrusions function as the first-side protrusions, and the original first-side protrusions function as the second-side protrusions. Therefore, when sandwiching the movable plate between the first partition plate and the second partition plate, it is not necessary to check the front and back of the movable plate.

[0014] The hydraulic vibration damping device of claim 5 achieves the following effect in addition to the effect achieved by the hydraulic vibration damping device of any one of claims 1 to 4. The communicating hole is blocked by the protruding portion contacting the entire periphery of the annular flat surface of the movable plate provided around the communicating hole. This flat surface is formed perpendicular to the axis of the protruding portion, making it easy to determine the position of the movable plate in the axial direction relative to the protruding portion. [Brief explanation of the drawings]

[0015] [Figure 1] 1 is a cross-sectional view of a liquid-sealed vibration-damping device according to a first embodiment. [Figure 2] FIG. 2 is a partially enlarged cross-sectional view of the liquid-sealed vibration-damping device, enlarging a portion II in FIG. 1. [Figure 3] FIG. 10 is a partially enlarged cross-sectional view of a liquid-filled vibration-damping device in which the first liquid chamber is excessively negatively pressurized. [Figure 4] FIG. 10 is a partially enlarged cross-sectional view of a liquid-sealed vibration-damping device according to a second embodiment. [Figure 5] FIG. 10 is a partially enlarged cross-sectional view of a liquid-sealed vibration-damping device according to a third embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0016] Preferred embodiments will now be described with reference to the accompanying drawings. FIG. 1 is a cross-sectional view of a hydraulic vibration damping device 10 in a first embodiment. FIG. 2 is a partially enlarged cross-sectional view of the hydraulic vibration damping device 10, enlarging part II in FIG. 1. Note that FIG. 1 shows the hydraulic vibration damping device 10 in a state where no vibration (load) is input. Unless otherwise specified, the state where no input is input will be described for each part of the hydraulic vibration damping device 10. Furthermore, in the following description, the upper side of the paper in FIG. 1 will be described as the upper side of the hydraulic vibration damping device 10, but the top and bottom of this hydraulic vibration damping device 10 do not necessarily coincide with the top and bottom of the vehicle to which the hydraulic vibration damping device 10 is attached.

[0017] The hydraulic vibration damping device 10 is an engine mount that elastically supports an automobile engine. The hydraulic vibration damping device 10 mainly comprises a first member 11 that is attached to the engine side, which is the vibration source, a cylindrical second member 12 that is attached to the vehicle body on the support side, and a vibration-damping base 13 made up of an elastic body that connects the first member 11 and the second member 12. The cross-sectional view of the hydraulic vibration damping device 10 in Figure 1 is an axial cross-sectional view that includes the axis C of the cylindrical second member 12.

[0018] The first member 11 is a boss fitting arranged on the axis C so as to be located above the second member 12, and is made of a metal such as steel or aluminum alloy. A bolt hole is formed in the upper end surface of the first member 11. The first member 11 is attached to the engine side via a bolt attached to the bolt hole.

[0019] The second member 12 is a cylindrical member centered on the axis C, and is made primarily of metal such as steel. The second member 12 includes a large diameter portion 12a at the upper end, a reduced diameter portion 12b that connects to the lower end of the large diameter portion 12a and has gradually smaller inner and outer diameters going downward, and a small diameter portion 12c that connects to the lower end of the reduced diameter portion 12b and has smaller inner and outer diameters than the large diameter portion 12a. For example, the second member 12 is attached to the vehicle body by being inserted into a cylindrical bracket provided on the vehicle body.

[0020] The vibration-isolating base 13 is a generally umbrella-shaped member made of an elastic material such as rubber or thermoplastic elastomer. The vibration-isolating base 13 is vulcanization-bonded to the lower part of the first member 11 and to the inner circumferential surfaces of the large-diameter portion 12a and the reduced-diameter portion 12b, connecting them together. A rubber membrane-like film portion 14 that covers the inner circumferential surface of the small-diameter portion 12c is continuous with the lower end of the vibration-isolating base 13. This film portion 14 is a part of the second member 12.

[0021] A diaphragm 15 is attached to the second member 12 via an attachment portion 16 so as to close the lower end opening of the small diameter portion 12c. The diaphragm 15 is a membrane made of an elastic material such as rubber. The attachment portion 16 is an annular member made of a metal such as steel. The outer periphery of the diaphragm 15 is vulcanization-bonded to the inner periphery of the attachment portion 16 all around.

[0022] A liquid chamber is formed by the sealed space partitioned by the vibration-isolating base 13, the second member 12, and the diaphragm 15. An antifreeze liquid (not shown) such as ethylene glycol is sealed in the liquid chamber. The liquid chamber is partitioned by a partition member 20 into a first liquid chamber 17, whose wall is made up of the vibration-isolating base 13, and a second liquid chamber 18, whose wall is made up of the diaphragm 15.

[0023] To attach the diaphragm 15 and the partition body 20 to the second member 12, first, the partition body 20 is inserted into the small diameter portion 12c of the second member 12 until it hits the step 13a of the vibration-isolating base 13 that protrudes radially inward from the upper end of the membrane portion 14. Next, the mounting portion 16 with the diaphragm 15 integrated therewith is inserted into the small diameter portion 12c, and then the small diameter portion 12c (second member 12) is reduced in diameter by drawing, and the outer peripheries of the partition body 20 and the mounting portion 16 are held by the membrane portion 14. In this way, the diaphragm 15 and the partition body 20 are attached to the second member 12.

[0024] The partition body 20 includes a cylindrical member 21 held inside the membrane portion 14, flat first and second partition plates 23 and 26 that separate the inner circumferential side of the cylindrical member 21 into upper and lower sections, and a movable plate 30 disposed between the first and second partition plates 23 and 26. The first partition plate 23 facing the first liquid chamber 17 and the second partition plate 26 facing the second liquid chamber 18 are stacked one on top of the other and joined by welding, bonding, or press-fitting.

[0025] The tubular member 21 is a cylindrical part made of metal or synthetic resin. The outer peripheral surface of the tubular member 21 is pressed against the small diameter portion 12c of the second member 12 via the membrane portion 14 over the entire circumference. A circumferential groove 22 having a length of approximately two circumferences is formed on the outer peripheral surface of the tubular member 21. A first orifice 19 is formed between this circumferential groove 22 and the membrane portion 14.

[0026] One end of the outer circumferential groove 22 opens to the upper end of the cylindrical member 21 radially inward from the step 13a, so that the first orifice 19 communicates with the first liquid chamber 17. The other end of the outer circumferential groove 22 opens to the lower end of the cylindrical member 21 radially inward from the contact position with the diaphragm 15, so that the first orifice 19 communicates with the second liquid chamber 18.

[0027] In this way, the first orifice 19 is a flow path that communicates the first fluid chamber 17 and the second fluid chamber 18. In order to attenuate shake vibrations, for example, when the vehicle is running, the first orifice 19 has a flow path cross-sectional area, length, cross-sectional circumference, etc. that are set so that the damping coefficient is large in a frequency band corresponding to the shake vibrations (for example, about 5 to 15 Hz) when large amplitude shake vibrations are input.

[0028] The first partition plate 23 is made of metal or synthetic resin and is formed in a disk shape perpendicular to the axis C. A cylindrical base portion 24 centered on the axis C protrudes downward (toward the second partition plate 26) from the radial center of the first partition plate 23. A plurality of first through holes 25 are formed in the first partition plate 23 radially outward of the base portion 24 and penetrate the first partition plate 23 in the plate thickness direction.

[0029] A cylindrical portion 23a extends upward from the outer peripheral edge of the first partition plate 23, and a flange 23b extends radially outward from the upper edge of the cylindrical portion 23a. The first partition plate 23 is attached to the cylindrical member 21 by fitting the cylindrical portion 23a onto the inner peripheral side of the cylindrical member 21 until the flange 23b contacts the upper end of the cylindrical member 21. The flange 23b, which has contacted the upper end of the cylindrical member 21, contacts the step 13a of the vibration-damping base 13. In addition, portions of the cylindrical portion 23a and the flange 23b in the circumferential direction are omitted so as not to block the opening of the outer peripheral groove 22 on the first liquid chamber 17 side.

[0030] The second partition plate 26 is a part that is molded integrally with the tubular member 21, and is formed in a circular plate shape that is perpendicular to the axis C. The outer peripheral edge of the second partition plate 26 is connected to the inner peripheral surface of the tubular member 21 along the entire circumference, and an accommodation space 29 is formed between the first partition plate 23 and the second partition plate 26 that are attached to the tubular member 21.

[0031] A substantially cylindrical protrusion 27, centered on the axis C, protrudes upward (toward the first partition plate 23) from the radial center of the second partition plate 26, at a position facing the base 24. The outer peripheral surface of the protrusion 27 includes a cylindrical surface 27a having a constant outer diameter centered on the axis C, and an inclined outer surface 27b that connects the upper end of the cylindrical surface 27a to the tip of the protrusion 27 and inclines radially inward toward the tip (toward the first partition plate 23). The outer diameter of the cylindrical surface 27a is smaller than the outer diameter of the base 24. The inclined outer surface 27b is a conical surface whose diameter decreases toward the tip of the protrusion 27, and its cross section including the axis C is linear.

[0032] A plurality of second through holes 28 are formed in the second partition plate 26 so as to penetrate in the plate thickness direction, radially outward from the protruding portion 27. The second through holes 28 are basically set to have a shape, size, and position symmetrical to (mirrored) the first through holes 25 of the first partition plate 23.

[0033] The movable plate 30 is a member made of an elastic body such as rubber or thermoplastic elastomer, and is formed in a disk shape perpendicular to the axis C. The movable plate 30 is disposed in the accommodation space 29 between the first partition plate 23 and the second partition plate 26.

[0034] The fluid pressure of the first fluid chamber 17 and the second fluid chamber 18 is applied to the movable plate 30 in the accommodation space 29 via the first through-hole 25 and the second through-hole 28 formed in the first partition plate 23 and the second partition plate 26, respectively. When the movable plate 30 is deformed or displaced by this fluid pressure, the vibration energy input to the fluid-filled vibration-damping device 10 is consumed, and the vibration can be damped by the fluid-filled vibration-damping device 10.

[0035] In order to suppress abnormal noise when the deformed or displaced movable plate 30 comes into contact with the first partition plate 23 or the second partition plate 26, a plurality of protrusions 31 are provided on both the upper and lower surfaces of the movable plate 30.

[0036] The multiple protrusions 31 are circular ring-shaped portions that are continuous around the entire circumference, and are arranged on concentric circles centered on the axis C. The base portion 24 and the protruding portion 27 are located radially inward of the radially innermost protrusion 31, and the innermost edges of the multiple first through holes 25 and second through holes 28 (the radially innermost edges of the edges of the multiple first through holes 25 and second through holes 28) are located radially inward of the radially innermost protrusion 31.

[0037] The multiple protrusions 31 are arranged alternately on both the upper and lower surfaces. This reduces the difference in rigidity between the thick and thin portions of the movable plate 30 compared to when the protrusions 31 are arranged in the same position on both the upper and lower surfaces. As a result, it is possible to suppress the likelihood of cracks starting from the thin portions of the movable plate 30, and improve the durability of the movable plate 30.

[0038] Furthermore, the height of the multiple protrusions 31 is the same, and the dimension of the accommodation space 29 in the direction of the axis C is greater than the overall thickness of the movable plate 30 (the distance in the direction of the axis C between the tips of the protrusions 31 on both the upper and lower sides). Furthermore, the inner diameter of the accommodation space 29 is greater than the outer diameter of the movable plate 30. Therefore, when the movable plate 30 is positioned in the center of the accommodation space 29, a second orifice that communicates between the first liquid chamber 17 and the second liquid chamber 18 is formed by the gap between the wall surface of the accommodation space 29 and the movable plate 30, the first through-hole 25, and the second through-hole 28.

[0039] The flow path cross-sectional area, length, cross-sectional circumference, etc. of this second orifice are set so that the damping coefficient becomes large in a frequency band corresponding to idle vibration (for example, about 15 to 50 Hz) when small amplitude idle vibration is input, in order to reduce idle vibration, for example, when the vehicle is idling (when stopped).

[0040] A circular communication hole 32, centered on the axis C in a plan view, is formed penetrating the plate thickness direction at the radial center of the movable plate 30 and inside the multiple protrusions 31. This communication hole 32 forms a short-circuit path that short-circuits the second orifice.

[0041] The inner peripheral surface of the communicating hole 32 has inclined inner surfaces 33, 34 that incline radially inward toward the center in the plate thickness direction. The inclined inner surface 33 is a conical surface whose diameter decreases downward and is located on the upper side of the communicating hole 32. The inclined inner surface 34 is a conical surface whose diameter decreases upward and is located on the lower side of the communicating hole 32.

[0042] The inclined inner surface 34 is in surface contact over the entire periphery with the inclined outer surface 27b of the protruding portion 27. While this surface contact is maintained, the communication hole 32 is blocked by the protruding portion 27, and the short-circuit path is cut off.

[0043] The inclined inner surfaces 33, 34 are formed symmetrically at their boundary surfaces, so that even when the movable plate 30 is turned upside down, the inclined inner surface 33 comes into surface contact with the inclined outer surface 27b of the protrusion 27 over the entire periphery. Therefore, when the movable plate 30 is disposed between the first partition plate 23 and the second partition plate 26, it is not necessary to check the front and back of the movable plate 30.

[0044] A plurality of first side protrusions 35 protrude from the inside of the plurality of protrusions 31 on the upper surface of the movable plate 30 and around the communicating holes 32 toward the first partition plate 23. Furthermore, a plurality of second side protrusions 36 protrude from the inside of the plurality of protrusions 31 on the lower surface of the movable plate 30 and around the communicating holes 32 toward the second partition plate 26.

[0045] The multiple first side protrusions 35 and second side protrusions 36 are arranged at intervals in the circumferential direction along the edge of the communicating hole 32. In this embodiment, the first side protrusions 35 and second side protrusions 36 are arranged in groups of four at equal intervals on all four sides of the communicating hole 32. The multiple first side protrusions 35 and second side protrusions 36 all have the same height, which is shorter than the height of the protrusion 31.

[0046] The multiple first side protrusions 35 contact the tip surface of the base portion 24 of the first partition plate 23 with the inclined inner surface 34 of the communicating hole 32 and the inclined outer surface 27b of the protrusion 27 in surface contact. In this contact state and when no vibration is input, the first side protrusions 35 are slightly pre-compressed (for example, by about 0.2 mm). Because the multiple first side protrusions 35, which are arranged at intervals in the circumferential direction, contact the base portion 24, the base portion 24 and the movable plate 30 are separated in part of the circumferential direction, and the communicating holes 32 can easily communicate with the first through-holes 25 around the base portion 24.

[0047] Furthermore, when vibrations that do not release the pre-compression of the first-side convex portions 35 are input to the hydraulic vibration damping device 10, or when no vibrations are input at all, the first-side convex portions 35 maintain surface contact between the inclined inner surface 34 and the inclined outer surface 27b. That is, the movable plate 30 is sandwiched between the base portion 24 and the inclined outer surface 27b of the protruding portion 27, and the state in which the communication hole 32 is blocked by the protruding portion 27 can be maintained. Furthermore, maintaining surface contact by the first-side convex portions 35 makes it easier to position the movable plate 30 relative to the protruding portion 27 in the direction of the axis C, and the movable plate 30 can be positioned in the center of the accommodation space 29 in the direction of the axis C.

[0048] Furthermore, since the inclined inner surface 34 and the inclined outer surface 27b, which come into surface contact, are both conical surfaces centered on the axis C and are similarly inclined relative to each other, it is easy to position the movable plate 30 radially relative to the protrusion 27, and the movable plate 30 can be positioned radially in the center within the storage space 29.

[0049] Due to these positioning arrangements, when the vibration (load) input from the vibration source to the liquid-filled vibration damping device 10 via the first member 11 is small, it is possible to maintain a communication state of the gap between the wall surface of the accommodation space 29 and the movable plate 30, and the second orifice through the first through-hole 25 and the second through-hole 28. On the other hand, when the vibration input to the liquid-filled vibration damping device 10 becomes large and the movable plate 30 comes into contact with the first partition plate 23 or the second partition plate 26, the second orifice enters a blocked state, and the damping characteristics of the first orifice 19 are mainly exerted.

[0050] The multiple second side protrusions 36 contact the cylindrical surface 27a of the protrusion 27 with the inclined inner surface 34 and the inclined outer surface 27b in surface contact. As a result, radial movement of the movable plate 30 relative to the protrusion 27 is restricted not only by the surface contact between the inclined inner surface 34 and the inclined outer surface 27b but also by the contact between the multiple second side protrusions 36 and the protrusion 27, and the movable plate 30 can be positioned radially relative to the protrusion 27.

[0051] The multiple first side protrusions 35 are located on the opposite side of the portion where the multiple second side protrusions 36 are lined up in the circumferential direction. In this embodiment, the second side protrusions 36 are located on the opposite side of each first side protrusion 35. This allows the movable plate 30 to be turned over, with the first side protrusions 35 serving as second side protrusions and the second side protrusions 36 serving as first side protrusions, and still allow the respective protrusions to function. Therefore, when placing the movable plate 30 between the first partition plate 23 and the second partition plate 26, it is not necessary to check the front and back of the movable plate 30.

[0052] 3 is a partially enlarged cross-sectional view of the liquid-filled vibration damping device 10 with an excessively negative pressure in the first liquid chamber 17. When a large load (large-amplitude vibration) is input to the liquid-filled vibration damping device 10 and the first liquid chamber 17 is excessively negatively pressurized, the movable plate 30 is displaced toward the first partition plate 23, the protrusion 31 and the first side convex portion 35 are crushed, and the inclined outer surface 27b of the protrusion 27 and the inclined inner surface 34 of the communication hole 32 are separated.

[0053] As a result, the communication hole 32 communicates not only with the first through-hole 25 but also with the second through-hole 28 around the protrusion 27. As a result, the short-circuit path is connected, allowing the liquid to quickly flow from the second liquid chamber 18 to the first liquid chamber 17, making it less likely that cavitation will occur due to negative pressure in the first liquid chamber 17.

[0054] When the first fluid chamber 17 is under positive pressure, the inclined inner surface 34 is pressed against the inclined outer surface 27b, similar to when no load is applied as shown in Fig. 2, so the short-circuit path is maintained in a blocked state. When the fluid pressure in the first fluid chamber 17, which is under negative pressure, is low, the inclined inner surface 34 is pressed against the inclined outer surface 27b in accordance with the amount of pre-compression of the first side convex portion 35, so the short-circuit path is maintained in a blocked state. In other words, the level of fluid pressure that opens the short-circuit path can be adjusted by adjusting the amount of pre-compression of the first side convex portion 35.

[0055] A mechanism that opens the short-circuit path when the first fluid chamber 17 is under excessive negative pressure and closes the short-circuit path in other cases is called a negative pressure relief valve. In this embodiment, the negative pressure relief valve is mainly formed by the movable plate 30 and the protrusion 27.

[0056] As described above, the movement of the movable plate 30 in the radial direction and in the direction of the axis C relative to the protruding portion 27 can be regulated by the contact between the inclined outer surface 27b and the inclined inner surface 34, the contact between the base portion 24 and the first side convex portion 35, and the contact between the cylindrical surface 27a and the second side convex portion 36. Therefore, since there is no need to sandwich the outer periphery of the movable plate 30 between the first partition plate 23 and the second partition plate 26 to position the movable plate 30 relative to the protruding portion 27, the negative pressure relief valve can be made more compact than one that has such a sandwiching portion.

[0057] Furthermore, the movable plate 30 has dot-like first and second side protrusions 35 and 36 arranged between the annular protrusions 31 and the communication holes 32 that are alternately arranged on both the upper and lower surfaces. Therefore, the movable plate 30 is prone to deformation in the vicinity of the communication holes 32 where the first and second side protrusions 35 and 36 are arranged, relative to the range in which the protrusions 31 are arranged. Therefore, when the negative pressure relief valve opens and puts the short-circuit path into a communication state, the movable plate 30 is prone to deformation in the vicinity of the communication holes 32, bending toward the second partition plate 26.

[0058] This allows the entrance of the short-circuit path on the second liquid chamber 18 side between the inclined outer surface 27b and the inclined inner surface 34 to be opened widely. This makes it easier for the liquid in the second liquid chamber 18 to flow into the short-circuit path, and makes it easier to quickly eliminate the negative pressure in the first liquid chamber 17.

[0059] Furthermore, to eliminate the need to position the movable plate 30 or check the front and back of the movable plate 30, second side protrusions 36 are arranged around the communication hole 32 and around the inlet of the shunt path on the second liquid chamber 18 side. However, because these second side protrusions 36 are arranged at intervals in the circumferential direction, it is difficult for the second side protrusions 36 to block the inlet of the shunt path on the second liquid chamber 18 side. Therefore, even when the second side protrusions 36 are provided, the liquid in the shunt path that is in a connected state by the negative pressure relief valve can flow smoothly, making it easier to quickly release the negative pressure in the first liquid chamber 17.

[0060] In a cross section including the axis C, the inclined outer surface 27b and the inclined inner surface 34 are formed linearly, so that when the negative pressure relief valve is opened, the short-circuit path between them can be made linear. This allows for smooth liquid flow in the short-circuit path that is connected by the negative pressure relief valve, making it easier to quickly release the negative pressure in the first liquid chamber 17.

[0061] Next, a second embodiment will be described with reference to Fig. 4. In the second embodiment, a small-diameter protrusion 46 provided at the tip of the protrusion 45 is inserted into a communication hole 49 to radially position a movable plate 48 with respect to the protrusion 45. Note that the same parts as those in the first embodiment are given the same reference numerals, and the following description will be omitted.

[0062] 4 is a partially enlarged cross-sectional view of a liquid-sealed vibration damping device 40 according to the second embodiment. The partition body 41 of the liquid-sealed vibration damping device 40 includes a cylindrical member 21 (see FIG. 1), flat first and second partition plates 42 and 44 that separate the inner periphery of the cylindrical member 21 into upper and lower sections, and a movable plate 48 disposed between the first and second partition plates 42 and 44.

[0063] The first partition plate 42 facing the first liquid chamber 17 and the second partition plate 44 facing the second liquid chamber 18 are stacked one on top of the other and joined by welding, bonding, or press-fitting. The first partition plate 42 has a first through-hole 43 formed in the radial center of the base portion 24 in addition to the multiple first through-holes 25, and is configured in the same way as the first partition plate 23 in the first embodiment, except that the outer diameter of the base portion 24 is increased.

[0064] The second partition plate 44 is a part that is molded integrally with the tubular member 21, and is formed in a circular plate shape that is perpendicular to the axis C. The outer peripheral edge of the second partition plate 44 is connected to the inner peripheral surface of the tubular member 21 along the entire circumference, and an accommodation space 29 is formed between the first partition plate 42 and the second partition plate 44 that are attached to the tubular member 21.

[0065] A substantially cylindrical protrusion 45, centered on the axis C, protrudes upward from the radial center of the second partition plate 44, at a position facing the base portion 24. A plurality of second through holes 28 are formed in the second partition plate 44 radially outward of the protrusion 45 and penetrate the second partition plate 44 in the plate thickness direction.

[0066] The protrusion 45 has a small diameter protrusion 46 that protrudes from the tip on the first partition plate 42 side. The outer peripheral surface of the protrusion 45 excluding the small diameter protrusion 46 is a cylindrical surface 27a with a constant outer diameter about the axis C. The outer peripheral surface of the small diameter protrusion 46 is a small diameter surface 47 with a smaller outer diameter than the cylindrical surface 27a, and is formed with a constant outer diameter about the axis C. The corner between the tip surface of the small diameter protrusion 46 and the small diameter surface 47 is chamfered to make it easier to insert the small diameter protrusion 46 into a communicating hole 49, which will be described later.

[0067] The movable plate 48 is a member made of an elastic body such as rubber or thermoplastic elastomer, and is formed in a disk shape perpendicular to the axis C. A plurality of protrusions 31 protrude from both the upper and lower surfaces of the movable plate 48. Of the plurality of protrusions 31 provided on the upper surface, at least the radially innermost protrusion 31 contacts the tip of the base portion 24 around the first through-hole 43 over the entire circumference. Note that even when the movable plate 48 is turned over, it is preferable that at least the radially innermost protrusion 31 contacts the tip of the base portion 24 around the first through-hole 43 over the entire circumference.

[0068] As a result, a second orifice is formed by the first through hole 25 on the radially outer side of the base portion 24, the second through hole 28, and the gap between the wall surface of the storage space 29 and the movable plate 48, connecting the first liquid chamber 17 and the second liquid chamber 18.

[0069] A circular communication hole 49, centered on the axis C in a plan view, is formed penetrating the movable plate 48 in the plate thickness direction at the radial center of the movable plate 48 and inside the multiple protrusions 31. This communication hole 49 forms a short-circuit path that short-circuits the second orifice. Even if the protrusion 31 is in contact with the tip of the base portion 24 over the entire circumference, the first through hole 43 is located radially inside the protrusion 31, so that the first through hole 43 and the communication hole 49 can easily be communicated with each other.

[0070] The inner peripheral surface of the communicating hole 49 is formed parallel to the axis C. The inner diameter of the communicating hole 49 and the outer diameter of the small diameter surface 47 of the small diameter protrusion 46 are approximately the same. By inserting the small diameter protrusion 46 into the communicating hole 49 and bringing the small diameter surface 47 into contact with the inner peripheral surface (restriction portion) of the communicating hole 49, it becomes easier to position the movable plate 48 radially relative to the protrusion 45, and the movable plate 48 can be positioned radially in the center within the accommodation space 29.

[0071] The movable plate 48 has annular flat surfaces 48a, 48b that are located inside the multiple protrusions 31 and are continuous via ridges to the inner circumferential surface of the communication hole 49. The flat surface 48a is a part of the upper surface of the movable plate 48 and is formed perpendicular to the axis C. The flat surface 48b is a part of the lower surface of the movable plate 48 and is formed perpendicular to the axis C. In the first embodiment, the first side protrusions 35 and the second side protrusions 36 are provided in the portions corresponding to these flat surfaces 48a, 48b, but in the second embodiment, the first side protrusions 35 and the second side protrusions 36 are not provided.

[0072] When the small diameter protrusion 46 is inserted into the communication hole 49 and the tip of the protrusion 45 radially outward of the small diameter protrusion 46 comes into surface contact with the flat surface 48b over the entire circumference, the communication hole 49 is blocked by the protrusion 45 and the short-circuit path is shut off. On the other hand, when the surface contact between the tip of the protrusion 45 and the flat surface 48b is released due to displacement (deformation) of the movable plate 48 and the small diameter protrusion 46 comes out of the communication hole 49, the short-circuit path is opened. In this way, in this embodiment as well, the negative pressure relief valve is formed mainly by the movable plate 48 and the protrusion 45.

[0073] When no vibration is input, the protrusion 45 and the flat surface 48b are in contact, and the protrusion 31 in contact with the base 24 is slightly pre-compressed (for example, by about 0.2 mm). As a result, when vibration is input to the liquid-sealed vibration-damping device 40 to an extent that the pre-compression of the protrusion 31 is not released, or when no vibration is input, the protrusion 31 maintains surface contact between the flat surface 48b and the tip of the protrusion 45, and the state in which the communication hole 49 is blocked by the protrusion 45 can be maintained (a state in which the short-circuit path is blocked).

[0074] Furthermore, by maintaining surface contact by the projections 31, it is easy to position the movable plate 48 in the direction of the axis C with respect to the protruding portions 45, and the movable plate 48 can be positioned at the center in the direction of the axis C within the accommodation space 29. Due to this positioning in the direction of the axis C and radial positioning by the communicating holes 49 and the small diameter protruding portions 46, it is not necessary to sandwich and position the outer periphery of the movable plate 48 between the first partition plate 42 and the second partition plate 44, as in the first embodiment, and therefore the negative pressure relief valve can be made more compact.

[0075] Even if the movable plate 48 is turned upside down, the tip of the protrusion 45 radially outward of the small diameter protrusion 46 will be in surface contact with the flat surface 48a over the entire periphery, thereby blocking the short-circuit path. Therefore, when placing the movable plate 48 between the first partition plate 42 and the second partition plate 44, it is not necessary to check the front and back of the movable plate 48.

[0076] The flat surface 48b (flat surface 48a) and the tip of the protrusion 45, which come into contact with each other, are formed perpendicular to the axis C, making it easy to determine the position of the movable plate 48 in the direction of the axis C relative to the protrusion 45. This makes it possible to suppress fluctuations in vibration-damping characteristics due to positional deviation of the movable plate 48 in the direction of the axis C.

[0077] Next, a third embodiment will be described with reference to Fig. 5. In the third embodiment, the tip of the protrusion 64 is brought into contact with the flat surface 48b around the communicating hole 49 to block the communicating hole 49, and the second side convex portion 36 is brought into contact with the outer circumferential surface of the protrusion 64 to position the movable plate 66. Note that the same parts as those in the first and second embodiments are given the same reference numerals, and the following description will be omitted.

[0078] 5 is a partially enlarged cross-sectional view of a liquid-sealed vibration damping device 60 according to the third embodiment. The partition body 61 of the liquid-sealed vibration damping device 60 includes a cylindrical member 21 (see FIG. 1), flat first and second partition plates 23 and 63 that separate the inner periphery of the cylindrical member 21 into upper and lower sections, and a movable plate 66 arranged between the first and second partition plates 23 and 63.

[0079] The second partition plate 63 is a part that is molded integrally with the cylindrical member 21, is formed in a circular plate shape perpendicular to the axis C, and faces the second liquid chamber 18. The outer peripheral edge of the second partition plate 63 is connected to the inner peripheral surface of the cylindrical member 21 over the entire circumference, and an accommodation space 29 is formed between the first partition plate 23 attached to the cylindrical member 21 and the second partition plate 63.

[0080] A protruding portion 64 having a generally cylindrical shape and centered on the axis C protrudes upward from the radial center of the second partition plate 63 at a position facing the base portion 24. The outer peripheral surface of the protruding portion 64 is a cylindrical surface 27a having a constant outer diameter and centered on the axis C. A plurality of second through holes 28 are formed in the second partition plate 63 radially outward of the protruding portion 64 and penetrating in the plate thickness direction.

[0081] The movable plate 66 is a member made of an elastic body such as rubber or thermoplastic elastomer, and is formed in a disk shape perpendicular to the axis C. The movable plate 66 includes a plurality of protrusions 31 protruding from both the upper and lower surfaces, a communication hole 49 formed to penetrate the protrusion 31 radially inward, flat surfaces 48a, 48b around the communication hole 49, and a plurality of first side protrusions 35 and second side protrusions 36 protruding from both the upper and lower surfaces around the flat surfaces 48a, 48b.

[0082] When no vibration is input, the contact between the tip of the protrusion 64 and the flat surface 48b blocks the communication hole 49, and the short-circuit path including the communication hole 49 is shut off. On the other hand, when the surface contact between the tip of the protrusion 64 and the flat surface 48b is released due to displacement (deformation) of the movable plate 66, the short-circuit path is opened. In this way, in this embodiment as well, the negative pressure relief valve is formed mainly by the movable plate 66 and the protrusion 64.

[0083] The contact between the base portion 24 and the multiple first side protrusions 35 and the contact between the tip of the protrusion 64 and the flat surface 48b makes it easy to position the movable plate 66 relative to the protrusion 64 in the direction of the axis C, and the movable plate 66 can be positioned at the center in the direction of the axis C within the accommodation space 29. Furthermore, the contact between the cylindrical surface 27a of the protrusion 64 and the multiple second side protrusions 36 makes it easy to position the movable plate 66 in the radial direction relative to the protrusion 64, and the movable plate 66 can be positioned at the center in the radial direction within the accommodation space 29. Therefore, as in the first and second embodiments, there is no need to sandwich the outer periphery of the movable plate 66 between the first partition plate 23 and the second partition plate 63 for positioning, and the negative pressure relief valve can be made more compact.

[0084] The tip of the second side protrusion 36 is curved in a dome shape. As a result, when the protrusion 64 is inserted radially inward of the multiple second side protrusions 36, the curved tip of the second side protrusion 36 can guide the protrusion 64 radially inward. As a result, when the internal pressure of the first fluid chamber 17 drops after the negative pressure relief valve opens, it is possible to prevent the tip of the protrusion 64 from hitting the tip of the second side protrusion 36 and maintaining the short-circuit path in a connected state, making it easier to close the negative pressure relief valve.

[0085] While the present invention has been described above based on the embodiments, it is not limited to the above embodiments, and it is readily apparent that various improvements and modifications are possible within the scope of the present invention. For example, the first member 11 may be disposed at a position offset radially from the axis C. In order to facilitate deformation of the movable plates 30, 48, and 66, multiple slits may be provided in the protrusion 31, dividing it in the circumferential direction.

[0086] The position and length of the first orifice 19 may be changed as appropriate. A liquid chamber separate from the first liquid chamber 17 and the second liquid chamber 18 may be formed in the partition body 20, 41, 61, etc. An orifice separate from the first orifice 19 may communicate between the two liquid chambers.

[0087] Furthermore, a cup-shaped metal cap may be provided below the diaphragm 15 (on the opposite side to the first liquid chamber 17 and the second liquid chamber 18), and an air chamber may be formed by the inner surface of the metal cap and the diaphragm 15. This air chamber may be an enclosed space that has an air spring effect. A through-hole may be provided in part of the metal cap to open the air chamber to the atmosphere, and a damping effect may be added by the air passing through the through-hole.

[0088] In the above embodiments, engine mounts have been exemplified as an application of the hydraulic vibration damping devices 10, 40, and 60, but the application can be any application. Other application targets include, for example, motor mounts, member mounts, and differential mounts. Furthermore, the first member 11 may be attached to the vibration source side, such as an engine, and the second member 12 may be attached to the vibration receiver side, such as a vehicle body. Alternatively, the second member 12 may be attached to the vibration source side and the first member 11 may be attached to the vibration receiver side.

[0089] A part of each of the above embodiments may be replaced with a part of another embodiment, or a part of each of the above embodiments may be added to another embodiment. For example, the outer peripheral surface of the small diameter protrusion 46 of the second embodiment may be replaced with the inclined outer surface 27b of the first embodiment, and the communication hole 49 of the second embodiment may be replaced with the communication hole 32 of the first embodiment.

[0090] Some of the above embodiments may be omitted. For example, the membrane portion 14 may be omitted, and the partitions 20, 41, 61 and the diaphragm 15 may be attached to the inner peripheral surface of the second member 12. The protrusion 31 may also be omitted. The second side protrusion 36 of the first embodiment may also be omitted. The base portion 24 may not protrude from the radial center of the first partition plate 23, and the first side protrusion 35 may be brought into contact with the radial center of the first partition plate 23.

[0091] Furthermore, the first side protrusion 35 of the first and third embodiments may be omitted. In this case, a groove may be formed in a corner on the tip side of the base 24, or a slit may be provided in the protrusion 31 that abuts the base 24, so that the communicating holes 32, 49 communicate with the first through hole 25. Alternatively, as in the second embodiment, the first through hole 43 provided in the center of the base 24 may be made to communicate with the communicating holes 32, 49. Note that, also in the second embodiment, instead of the first through hole 43, a groove may be formed in a corner on the tip side of the base 24, or a slit may be provided in the protrusion 31 that abuts the base 24.

[0092] In the above embodiment, the case where the multiple protrusions 31 are arranged on concentric circles has been described, but the centers of the multiple protrusions 31 may be offset from each other. The protrusions may also be formed in a dotted, linear, curved, or spiral shape. The multiple protrusions may be arranged periodically or randomly. Furthermore, the multiple protrusions may be provided in the same position on both the top and bottom surfaces.

[0093] In the first embodiment, the inclined outer surface 27b and the inclined inner surfaces 33, 34 are conical surfaces, but for example, the inclined outer surface and the inclined inner surface may be inclined so that a cross section including the axis C is curved. Note that it is easier to form the inclined outer surface 27b and the inclined inner surfaces 33, 34 when they are conical surfaces. [Explanation of symbols]

[0094] 10, 40, 60 Liquid-filled vibration isolation device 11 First member 12 Second member 13 Vibration-isolating base 15 diaphragm 17 1st liquid chamber 18 2nd liquid chamber 19 First orifice (orifice) 20, 41, 61 Partition 23,42 First partition 24 Base 25,43 First through hole 26,44,63 Second partition 27,45,64 Protrusion 27b Slanted outer surface 28 Second through hole 30,48,66 Movable plate 32,49 Communication hole 33, 34 Inclined inner surface (restriction part) 35 1st side convex part 36 Second side convex portion (restriction portion) 48a,48b flat surface C axis center

Claims

1. a first member and a cylindrical second member; a vibration-isolating base made of an elastic material that connects the first member and the second member; a diaphragm made of an elastic material attached to the second member and forming a liquid chamber filled with liquid between the diaphragm and the vibration-isolating base; a partition member that separates the liquid chamber into a first liquid chamber and a second liquid chamber; an orifice communicating the first liquid chamber with the second liquid chamber; the partition body includes a first partition plate having a first through-hole formed therethrough in a plate thickness direction and facing the first liquid chamber; a second partition plate having a second through hole formed therethrough in a plate thickness direction and facing the second liquid chamber; a movable plate made of an elastic body, disposed between the first partition plate and the second partition plate, and having a communication hole formed through the center in the radial direction, the first partition plate is in contact with the movable plate so as to allow communication between the communication hole and the first through hole; the second partition plate includes a protruding portion that protrudes toward the first partition plate and sandwiches the movable plate between itself and the first partition plate to close the communication hole when no vibration is input, The first partition plate has a base portion provided at a position opposite to the protrusion portion in the plate thickness direction, When no vibration is input, the movable plate is sandwiched only between the base portion and the protrusion portion in the plate thickness direction, When the first liquid chamber reaches a predetermined negative pressure state, the protrusion and the movable plate are separated, and the first liquid chamber and the second liquid chamber communicate with each other through the communication hole. The liquid-filled vibration-damping device is characterized in that the movable plate includes a restricting portion that contacts the outer peripheral surface of the protruding portion and restricts radial movement of the movable plate relative to the protruding portion.

2. an outer peripheral surface of the protrusion has an inclined outer surface that inclines radially inward toward the first partition plate, A liquid-sealed vibration-damping device as described in claim 1, characterized in that the inner surface of the communicating hole is inclined radially inward as it approaches the first partition plate, and has an inclined inner surface that contacts the inclined outer surface around the entire circumference to form the regulating portion.

3. A first member and a cylindrical second member, a vibration-isolating base made of an elastic material that connects the first member and the second member; a diaphragm made of an elastic material attached to the second member and forming a liquid chamber filled with liquid between the diaphragm and the vibration-isolating base; a partition member that separates the liquid chamber into a first liquid chamber and a second liquid chamber; an orifice communicating the first liquid chamber with the second liquid chamber; the partition body includes a first partition plate having a first through-hole formed therethrough in a plate thickness direction and facing the first liquid chamber; a second partition plate having a second through hole formed therethrough in a plate thickness direction and facing the second liquid chamber; a movable plate made of an elastic body, disposed between the first partition plate and the second partition plate, and having a communication hole formed through the center in the radial direction, the first partition plate is in contact with the movable plate so as to allow communication between the communication hole and the first through hole; the second partition plate includes a protruding portion that protrudes toward the first partition plate and sandwiches the movable plate between itself and the first partition plate to close the communication hole when no vibration is input, the movable plate includes a restricting portion that contacts an outer peripheral surface of the protruding portion and restricts radial movement of the movable plate relative to the protruding portion; a plurality of second side protrusions arranged at intervals in the circumferential direction around the communication hole and protruding toward the second partition plate, A liquid-filled vibration-damping device, characterized in that the plurality of second-side convex portions come into contact with the outer peripheral surface of the protruding portion to form the restricting portion.

4. the movable plate includes a plurality of first side protrusions protruding at intervals in the circumferential direction from an opposite side to a portion where the plurality of second side protrusions are arranged in the circumferential direction, 4. The hydraulic vibration damping device according to claim 3, wherein the first through-holes are positioned radially outward of the first side protrusions arranged in the circumferential direction.

5. the movable plate has an annular flat surface formed perpendicular to the axis of the protrusion and provided around the communication hole, 5. The hydraulic vibration-damping device according to claim 1, wherein the protrusion contacts the entire periphery of the flat surface, thereby blocking the communication hole.

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