Liquid sealed type antivibration device

Abstract

To provide a liquid sealed type antivibration device for easily enabling a reduction in the weight and size of a partition body and attaining the multi-functionality while securing a flow amount when a valve is opened.SOLUTION: A short circuit path formed by an outside hole 24c, a through hole 27b and a storage space 29 performs communication when a valve 30 is opened, and shut-off when the valve 30 is closed. In the valve 30, a first seal part 33 and a second seal part 34 are provided on the radial outside with respect to an annular held part 31 to be held between a first partition plate 23 and a second partition plate 26 for actualizing shut-off of the short circuit path, thus easily enabling a reduction in the weight and size of a partition body 20 and attaining the multi-functionality while securing a flow amount when the valve 30 is opened.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a liquid-filled vibration isolator, and more particularly to a liquid-filled vibration isolator that can easily reduce the weight, size, and multifunctionalize a partition while ensuring the flow rate when the valve is open.

Background Art

[0002] As a vibration isolator for supporting a vibration source such as an engine on a vehicle body (support side), for example, a liquid-filled vibration isolator disclosed in Patent Document 1 is known. In the liquid-filled vibration isolator disclosed in Patent Document 1, a liquid chamber formed inside is partitioned into a first liquid chamber and a second liquid chamber by a partition, and the first liquid chamber and the second liquid chamber communicate with each other through an orifice. The partition includes a first partition plate facing the first liquid chamber, a second partition plate facing the second liquid chamber, and an elastic valve disposed in a disk-shaped accommodation space formed therebetween.

[0003] The valve of Patent Document 1 includes a disk-shaped disk membrane portion, an annular first seal portion and a second seal portion protruding upward and downward respectively from the outer edge portion of the disk membrane portion, an annular sandwiched portion sandwiched between the first partition plate and the second partition plate, and a connecting portion connecting the inner peripheral edge of the sandwiched portion and the outer edge portion of the disk membrane portion at a plurality of locations in the circumferential direction. An outer hole is formed through the first partition plate in the plate thickness direction on the radially outer side of the first seal portion. A through hole is formed through the second partition plate in the plate thickness direction on the radially inner side of the second seal portion.

[0004] A short circuit path connecting the first liquid chamber and the second liquid chamber is formed by the outer hole, the through hole, and the accommodation space. The valve is a cavitation valve that switches between communication and interruption of this short circuit path. In a state where no load is input to the liquid-filled vibration isolator, the first seal portion of the valve contacts the first partition plate, and the entire circumference of the second seal portion contacts the second partition plate, respectively, and the short circuit path is blocked (the valve is closed). On the other hand, when the first liquid chamber is excessively depressurized, the first seal portion pressed against the first partition plate is crushed, the space between the second partition plate and the second seal portion is separated, and the short circuit path is communicated (the valve is opened).

Prior Art Documents

Patent Document

[0005]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0006] However, in the above - mentioned Patent Document 1, since the outer holes and through - holes, which are part of the short - circuit path, are small, the flow rate of the short - circuit path when the valve is open is low. Furthermore, the flow rate of the short - circuit path is also reduced by a plurality of connecting parts arranged across the short - circuit path. Also, in order to ensure the flow rate, simply increasing the diameters of the outer holes, through - holes, the first seal part, and the second seal part will also increase the diameter of the disc membrane part inside the first seal part and the second seal part. Then, the proportion of the valve in the partition body becomes large, and problems such as difficulty in reducing the weight and size of the partition body and difficulty in providing other functions to the partition body occur.

[0007] The present invention has been made to solve the above - mentioned problems, and an object thereof is to provide a liquid - filled vibration isolator that can easily reduce the weight, size, and increase the functionality of the partition body while ensuring the flow rate when the valve is open.

Means for Solving the Problems

[0008] To achieve this object, the liquid-sealed vibration isolator of the present invention includes a first member and a cylindrical second member, a vibration isolation base made of an elastic body that connects the first member and the second member, an elastic diaphragm attached to the second member and forming a liquid chamber in which a liquid is enclosed between the vibration isolation base, a partition body that partitions the liquid chamber into a first liquid chamber and a second liquid chamber, and an orifice that communicates the first liquid chamber and the second liquid chamber. The partition body includes a first partition plate facing the first liquid chamber, a second partition plate facing the second liquid chamber and forming an annular accommodation space between the first partition plate, and a valve made of an elastic body sandwiched between the first partition plate and the second partition plate. The valve includes an annular sandwiched portion sandwiched between the first partition plate and the second partition plate over the entire circumference, an annular annular film portion extending radially outward from the sandwiched portion and projecting into the accommodation space, a first seal portion projecting from the outer edge portion of the annular film portion toward the first partition plate side in the axial direction of the annular film portion, and an annular second seal portion projecting from the entire circumference of the outer edge portion of the annular film portion toward the second partition plate side in the axial direction. A plurality of outer holes communicating the first liquid chamber and the accommodation space are formed through the first partition plate radially outside the first seal portion. A plurality of through holes communicating the second liquid chamber and the accommodation space are formed through the second partition plate radially inside the second seal portion and radially outside the sandwiched portion. A short circuit path connecting the first liquid chamber and the second liquid chamber is formed by the outer holes, the through holes, and the accommodation space. When the first seal portion contacts the first partition plate and the second seal portion contacts the second partition plate over the entire circumference, the short circuit path is blocked. When the annular film portion is displaced toward the first liquid chamber side and the second seal portion is separated from the second partition plate, the short circuit path communicates.

Effect of the Invention

[0009] According to the liquid-sealed vibration isolator described in claim 1, similar to Patent Document 1, the short circuit path formed by the outer hole, the through hole, and the accommodation space communicates when the valve opens and is blocked when the valve closes. The valve is provided with a first seal portion and a second seal portion for blocking the short circuit path on the radially outer side with respect to the annular sandwiched portion sandwiched between the first partition plate and the second partition plate. Therefore, it is easier to increase the diameters of the first seal portion and the second seal portion than when the first seal portion and the second seal portion are provided on the radially inner side with respect to the sandwiched portion. As a result, it is easy to enlarge the outer hole provided on the radially outer side of the first seal portion and the through hole provided on the radially inner side of the second seal portion, so that it is easy to ensure the flow rate of the short circuit path when the valve is open. Furthermore, since there is no sandwiched portion on the radially outer side with respect to the first seal portion and the second seal portion, it is possible to prevent a plurality of connecting portions as in Patent Document 1 that connect them from crossing the short circuit path. As a result, the flow rate of the short circuit path when the valve is open can be ensured.

[0010] Since the first seal portion and the second seal portion are located on the radially outer side with respect to the annular sandwiched portion, it is easy to provide other functions (such as a characteristic tuning mechanism) inside the sandwiched portion. Also, for example, by not providing anything inside the sandwiched portion, it is easy to reduce the weight and size of the partition body.

[0011] According to the liquid-sealed vibration isolator described in claim 2, in addition to the effects exhibited by the liquid-sealed vibration isolator described in claim 1, the following effects are exhibited. The sandwiched portion has outer steps rising from both axial sides of the annular film portion and is formed thicker axially with respect to the annular film portion. On the valve-side surface of the second partition plate, a second outward convex portion protruding toward the annular film portion is provided from between the portion in contact with the sandwiched portion and the through hole. Thereby, even if the valve tends to shift radially with respect to the second partition plate, the second outward convex portion and the outer step are caught, so that it is difficult for the valve to shift radially.

[0012] On one side, the valve-side surface of the first partition plate is formed flush with the portion in contact with the clamped portion and the portion facing the annular film portion, and there is no convex portion protruding toward the annular film portion. As a result, when the first seal portion pressed against the first partition plate is crushed and the annular film portion is displaced toward the first liquid chamber, it is possible to prevent this displacement from being restricted by the convex portion when the valve opens. Therefore, the gap between the second partition plate and the second seal portion can be increased, and the flow rate of the short circuit path when the valve is open can be increased.

[0013] According to the liquid-filled vibration isolator described in claim 3, in addition to the effects exhibited by the liquid-filled vibration isolator described in claim 2, the following effects are exhibited. In the liquid-filled vibration isolator, the outer peripheral edge of the plate-shaped elastic film portion made of an elastic body is connected to the inner peripheral edge of the clamped portion of the valve. A first central hole for exposing the elastic film portion to the first liquid chamber is formed through the first partition plate. A second central hole for exposing the elastic film portion to the second liquid chamber is formed through the second partition plate at a position axially opposed to the first central hole. Since the thus-exposed elastic film portion deforms according to the liquid pressure difference between the first liquid chamber and the second liquid chamber, the spring constant of the liquid-filled vibration isolator can be adjusted by the elastic film portion. That is, according to the liquid-filled vibration isolator, a characteristic tuning mechanism by the elastic film portion can be provided inside the clamped portion.

[0014] The liquid-filled vibration isolator described in claim 4 incorporates claim 2 and has the same configuration as claim 3. Therefore, in addition to the effects exhibited by the liquid-filled vibration isolators described in claims 2 and 3, the following effects are exhibited. The inner peripheral edge of the clamped portion has inner steps rising from the outer peripheral edge of the elastic film portion to both sides in the axial direction. A second inner convex portion protruding toward the elastic film portion is provided on the valve-side surface of the second partition plate between the portion in contact with the clamped portion and the second central hole. As a result, the second inner convex portion faces the inner step in the radial direction, and the second outer convex portion faces the outer step in the radial direction. That is, since the clamped portion can be accommodated between the second inner convex portion and the second outer convex portion in the radial direction, the valve can be made more difficult to shift in the radial direction with respect to the second partition plate.

[0015] Also, when the clamped portion pressed against the first partition plate collapses and the valve opens, since the first partition plate has no outer step and no convex portion facing the radial direction, when the clamped portion comes out from between the second inner convex portion and the second outer convex portion, the clamped portion may shift in the radial direction with respect to them. However, on the valve-side surface of the first partition plate, a first inner convex portion that protrudes toward the elastic membrane portion from between the portion in contact with the clamped portion and the first central hole is provided. Therefore, even if the clamped portion comes out from between the second inner convex portion and the second outer convex portion, the first inner convex portion and the inner step catch on, making it difficult for the valve to shift in the radial direction.

Brief Description of the Drawings

[0016]

Figure 1

Figure 2

Figure 3

Figure 4

Modes for Carrying Out the Invention

[0017] Hereinafter, preferred embodiments will be described with reference to the accompanying drawings. FIG. 1 is a cross-sectional view of the liquid-filled vibration isolator 10 in the first embodiment. Note that FIG. 1 shows the no-load state in which no vibration (load) is input to the liquid-filled vibration isolator 10. Unless otherwise specified, each part of the liquid-filled vibration isolator 10 will be described in the no-load state. Also, in the following description, the upper side on the paper surface of FIG. 1 will be described as the upper side of the liquid-filled vibration isolator 10 and the like, but the up and down of this liquid-filled vibration isolator 10 does not necessarily coincide with the up and down of the vehicle to which the liquid-filled vibration isolator 10 is attached.

[0018] The liquid-filled vibration isolator 10 is an engine mount that elastically supports the engine of an automobile. The liquid-filled vibration isolator 10 mainly includes a first member 11 attached to the engine side, which is the vibration source, a cylindrical second member 12 attached to the vehicle body on the support side, and a vibration isolation base 13 composed of an elastic body that connects the first member 11 and the second member 12. Note that the cross-sectional view of the liquid-filled vibration isolator 10 in Fig. 1 is an axial cross-sectional view including the axis C of the cylindrical second member 12. The direction of the axis C is the vertical direction of the liquid-filled vibration isolator 10. Hereinafter, the direction perpendicular to the axis C will be simply referred to as the radial direction, and the direction around the axis C will be simply referred to as the circumferential direction for explanation.

[0019] 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 formed of a metal such as steel or an aluminum alloy. Bolt holes are formed on the upper end surface of the first member 11. The first member 11 is attached to the engine side via bolts attached to the bolt holes.

[0020] The second member 12 is a cylindrical member centered on the axis C, and is mainly formed of a metal such as steel. The second member 12 includes a large-diameter portion 12a on the upper end side, a reduced-diameter portion 12b that is continuous with the lower end of the large-diameter portion 12a and whose inner and outer diameters gradually decrease downward, and a small-diameter portion 12c that is continuous with the lower end of the reduced-diameter portion 12b and has inner and outer diameters smaller than those of the large-diameter portion 12a. For example, the second member 12 is attached to the vehicle body side by being inserted into a cylindrical bracket provided on the vehicle body side.

[0021] The vibration isolation base 13 is a member made of an elastic body such as rubber or thermoplastic elastomer formed in a substantially umbrella shape. The vibration isolation base 13 is vulcanized and adhered to the lower part of the first member 11 and the inner peripheral surfaces of the large-diameter portion 12a and the reduced-diameter portion 12b, respectively, to connect them. A rubber film-like film portion 14 that covers the inner peripheral surface of the small-diameter portion 12c is continuous with the lower end portion of the vibration isolation base 13. This film portion 14 is a part of the second member 12.

[0022] 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 film made of an elastic body such as rubber. The attachment portion 16 is an annular member made of metal such as steel. The outer peripheral portion of the diaphragm 15 is vulcanized and adhered to the inner peripheral portion of the attachment portion 16 over the entire circumference.

[0023] A liquid chamber is formed by a sealed space defined by the vibration-proof base 13, the second member 12, and the diaphragm 15. An antifreezing liquid (not shown) such as ethylene glycol is enclosed in the liquid chamber. The liquid chamber is partitioned by a partition body 20 into a first liquid chamber 17 in which the vibration-proof base 13 constitutes a part of the chamber wall and a second liquid chamber 18 in which the diaphragm 15 constitutes a part of the chamber wall.

[0024] In order 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 a step 13a of the vibration-proof base 13 that projects stepwise inward in the radial direction from the upper end of the film portion 14. Next, after the attachment portion 16 integrated with the diaphragm 15 is inserted into the small-diameter portion 12c, the small-diameter portion 12c (second member 12) is reduced in diameter by drawing, and the outer peripheral portions of the partition body 20 and the attachment portion 16 are held by the film portion 14. Thereby, the diaphragm 15 and the partition body 20 are attached to the second member 12.

[0025] Referring to FIG. 2 in addition to FIG. 1, the partition body 20 will be described. FIG. 2 is a plan view of the partition body 20. A cross-section of the partition body 20 along line I-I in FIG. 2 is shown in FIG. 1. The partition body 20 includes a cylindrical member 21 held inside the film portion 14, flat plate-shaped first partition plates 23 and second partition plates 26 that partition the inner peripheral side of the cylindrical member 21 vertically, and valves 30 and elastic film portions 40 disposed between the first partition plates 23 and the second partition plates 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 overlapped vertically with each other and joined by welding, adhesion, or press-fitting.

[0026] The cylindrical member 21 is a cylindrical part made of metal or synthetic resin. The outer peripheral surface of the cylindrical member 21 is pressed against the small-diameter part 12c of the second member 12 via the film part 14 over the entire circumference. An outer peripheral groove 22 having a length of approximately two turns is formed on the outer peripheral surface of the cylindrical member 21. An orifice 19 is formed between the outer peripheral groove 22 and the film part 14.

[0027] One end of the outer peripheral groove 22 opens to the inner peripheral surface of the cylindrical member 21 above the first partition plate 23 or to the upper end of the cylindrical member 21, whereby the orifice 19 communicates with the first liquid chamber 17. The other end of the outer peripheral groove 22 opens to the inner peripheral surface of the cylindrical member 21 below the second partition plate 26 or to the lower end of the cylindrical member 21, whereby the orifice 19 communicates with the second liquid chamber 18.

[0028] In this way, the orifice 19 is a flow path that communicates the first liquid chamber 17 and the second liquid chamber 18. The orifice 19 is set such that, for example, in order to attenuate the shake vibration during vehicle travel, the attenuation coefficient becomes large in a frequency band corresponding to the shake vibration (for example, about 5 to 15 Hz) when a large-amplitude shake vibration is input, such as the cross-sectional area, length, and circumferential perimeter of the flow path of the orifice 19.

[0029] The first partition plate 23 is a part made of metal or synthetic resin and is formed in an annular plate shape perpendicular to the axis C. A plurality of holes are formed through the first partition plate 23 in the plate thickness direction (vertical direction). The plurality of holes include a first central hole 24a that forms the inner peripheral surface of the first partition plate 23, a plurality (eight in this embodiment) of inner holes 24b provided radially outward from the first central hole 24a, and a plurality (eight in this embodiment) of outer holes 24c provided radially outward from the inner holes 24b.

[0030] The first central hole 24a is a circular hole centered on the axis C. The inner diameter of the first central hole 24a is at least half of the inner diameter of the cylindrical member 21. The plurality of inner holes 24b are each formed in an arc shape centered on the axis C and are arranged at equal intervals in the circumferential direction. The circumferential lengths of the plurality of inner holes 24b are the same as each other, and the intervals between the inner holes 24b are sufficiently smaller than that length.

[0031] The plurality of outer holes 24c are each formed in an arc shape centered on the axis C and are arranged at equal intervals in the circumferential direction. The circumferential lengths of the plurality of outer holes 24c are the same as each other, and the intervals between the outer holes 24c are sufficiently smaller than that length. The intervals between the outer holes 24c are the same as the intervals between the inner holes 24b. The outer holes 24c are arranged at positions where the inner holes 24b are projected radially outward.

[0032] The first partition plate 23 includes a first clamping portion 23a which is an annular portion between the first central hole 24a and the plurality of inner holes 24b, an intermediate portion 23b which is an annular portion between the plurality of inner holes 24b and the plurality of outer holes 24c, and an outer peripheral portion 23c which is an annular portion from the plurality of outer holes 24c to the outer peripheral edge of the first partition plate 23.

[0033] From the lower surface of the first clamping portion 23a, a first outer convex portion 25a projects so as to extend the outer edge on the inner hole 24b side, and a first inner convex portion 25b projects so as to extend the inner edge on the first central hole 24a side. Both the first outer convex portion 25a and the first inner convex portion 25b are annular portions centered on the axis C. A groove is formed over the entire circumference between the first outer convex portion 25a and the first inner convex portion 25b. The bottom of the groove is located on the same plane as the lower surfaces of the intermediate portion 23b and the outer peripheral portion 23c.

[0034] A cylindrical portion 23d extends upward substantially perpendicularly from the outer peripheral portion 23c. The cylindrical portion 23d is fitted on the inner peripheral side of the cylindrical member 21. By this cylindrical portion 23d, the contact area between the cylindrical member 21 and the first partition plate 23 can be widened in the vertical direction, and their fitting can be stabilized.

[0035] The second partition plate 26 is a portion integrally formed with the cylindrical member 21 and is formed in an annular plate shape perpendicular to the axis C. A plurality of holes are formed through the second partition plate 26 in the plate thickness direction (vertical direction). Among the plurality of holes, there are a second central hole 27a forming the inner peripheral surface of the second partition plate 26 and a plurality of through holes 27b provided at a distance radially outward from the second central hole 27a.

[0036] The second central hole 27a is a circular hole centered on the axis C and is disposed at a position vertically opposite to the first central hole 24a. The inner diameter of the second central hole 27a is the same as that of the first central hole 24a.

[0037] The plurality of through holes 27b are each formed in an arc shape centered on the axis C and are arranged at equal intervals in the circumferential direction. The plurality of through holes 27b are respectively provided at positions vertically opposite to the plurality of inner holes 24b. The circumferential lengths of the plurality of through holes 27b are the same as each other and are the same as the circumferential length of the inner hole 24b. The interval between the through holes 27b is sufficiently smaller than that length, and the interval between the through holes 27b is the same as the interval between the inner holes 24b.

[0038] The second partition plate 26 includes a second clamping portion 26a which is an annular portion between the second central hole 27a and the plurality of through holes 27b, and an outer peripheral portion 26b which is an annular portion from the plurality of through holes 27b to the outer peripheral edge of the second partition plate 26.

[0039] From the upper surface of the second clamping portion 26a, a second outer convex portion 28a protrudes so as to extend the outer edge on the side of the through hole 27b, and a second inner convex portion 28b protrudes so as to extend the inner edge on the side of the second central hole 27a. Both the second outer convex portion 28a and the second inner convex portion 28b are annular portions centered on the axis C. The second outer convex portion 28a is vertically opposite to the first outer convex portion 25a. The second inner convex portion 28b is vertically opposite to the first inner convex portion 25b. A groove is formed over the entire circumference between the second outer convex portion 28a and the second inner convex portion 28b. The bottom of the groove is located on the same plane as the upper surface of the outer peripheral portion 26b.

[0040] The outer peripheral edge of the outer peripheral portion 26b is connected to the inner peripheral surface of the cylindrical member 21. From a part on the outer peripheral edge side of the outer peripheral portion 26b, a cylindrical step portion 26c extends substantially vertically upward. The outer peripheral surface of this step portion 26c is also connected to the inner peripheral surface of the cylindrical member 21. By overlapping the outer peripheral portion 23c of the first partition plate 23 on the upper end of the step portion 26c, the first partition plate 23 and the second partition plate 26 are positioned. Thereby, an annular accommodation space 29 is formed between the first partition plate 23 and the second partition plate 26.

[0041] The accommodation space 29 is a space radially outside the first clamping portion 23a and the second clamping portion 26a, and an outer peripheral wall surface is formed by the inner peripheral surface of the step portion 26c. The accommodation space 29 communicates with the first liquid chamber 17 through the inner hole 24b and the outer hole 24c. The accommodation space 29 communicates with the second liquid chamber 18 through the through hole 27b. These outer holes 24c, the accommodation space 29, and the through hole 27b form a short circuit path connecting the first liquid chamber 17 and the second liquid chamber 18.

[0042] The valve 30 is a cavitation valve that switches between the communication and the blockage of this short circuit path. The valve 30 is composed of an elastic body such as rubber or thermoplastic elastomer, and is formed in an annular plate shape centered on the axis C. The valve 30 includes an annular clamped portion 31 that is clamped over the entire circumference by the first clamping portion 23a and the second clamping portion 26a, an annular film portion 32 that extends radially outward from the clamped portion 31 and projects into the accommodation space 29, a first seal portion 33 that projects upward (toward the first partition plate 23 in the axial direction) from the outer edge portion of the annular film portion 32, and a second seal portion 34 that projects downward (toward the second partition plate 26 in the axial direction) from the outer edge portion of the annular film portion 32.

[0043] The clamped portion 31 is an annular portion centered on the axis C. The outer peripheral edge of a disk-shaped elastic film portion 40 is connected to the inner peripheral edge of the clamped portion 31 so as to close the inner peripheral side of the valve 30. The elastic film portion 40 is a portion made of an elastic body integrally formed with the valve 30. Therefore, the productivity of the valve 30 and the elastic film portion 40 can be improved as compared with the case where they are integrally formed after being separately formed.

[0044] The elastic membrane portion 40 is exposed from the first partition plate 23 through the first central hole 24a, and the upper surface of the elastic membrane portion 40 constitutes a part of the wall surface of the first liquid chamber 17. Similarly, the elastic membrane portion 40 is exposed from the second partition plate 26 through the second central hole 27a, and the lower surface of the elastic membrane portion 40 constitutes a part of the wall surface of the second liquid chamber 18. According to the liquid pressure difference between the first liquid chamber 17 and the second liquid chamber 18, the elastic membrane portion 40 between them is deformed, and the spring constant of the liquid-filled vibration isolator 10 can be adjusted by this deformation. That is, according to the liquid-filled vibration isolator 10, a characteristic tuning mechanism by the elastic membrane portion 40 can be provided inside the clamped portion 31.

[0045] The elastic membrane portion 40 and the annular membrane portion 32 of the valve 30 have substantially the same thickness (dimension in the vertical direction), and their upper and lower surfaces are located on the same plane respectively. With respect to these elastic membrane portion 40 and annular membrane portion 32, the clamped portion 31 is formed thick on both the upper and lower sides. Therefore, the clamped portion 31 includes an outer step 31a that rises substantially vertically upward from the upper surface of the annular membrane portion 32, an outer step 31b that rises substantially vertically downward from the lower surface of the annular membrane portion 32, an inner step 31c that rises substantially vertically upward from the upper surface of the elastic membrane portion 40, and an inner step 31d that rises substantially vertically downward from the lower surface of the elastic membrane portion 40. The outer steps 31a, 31b form a part of the outer peripheral edge of the clamped portion 31, and the inner steps 31c, 31d form a part of the inner peripheral edge of the clamped portion 31.

[0046] The clamped portion 31 sandwiched between the first clamping portion 23a and the second clamping portion 26a is accommodated between the radial directions of a first outer convex portion 25a protruding toward the annular membrane portion 32 and a first inner convex portion 25b protruding toward the elastic membrane portion 40, and contacts the first clamping portion 23a. Similarly, the clamped portion 31 is accommodated between the radial directions of a second outer convex portion 28a protruding toward the annular membrane portion 32 and a second inner convex portion 28b protruding toward the elastic membrane portion 40, and contacts the second clamping portion 26a. At this time, the first outer convex portion 25a and the outer step 31a, the first inner convex portion 25b and the inner step 31c, the second outer convex portion 28a and the outer step 31b, and the second inner convex portion 28b and the inner step 31d are respectively opposed in the radial direction.

[0047] The annular film portion 32 is an annular plate-shaped portion centered on the axis C. The outer edge portion of the annular film portion 32 is separated from the inner peripheral surface of the stepped portion 26c over the entire circumference. The annular film portion 32 faces the inner hole 24b and the through hole 27b in the vertical direction.

[0048] The first seal portion 33 and the second seal portion 34 are portions that project vertically from the entire circumference of the outer edge portion of the annular film portion 32 and are formed in an annular shape centered on the axis C. The outer peripheral surfaces of the first seal portion 33 and the second seal portion 34 are formed in a tapered shape that reduces in diameter toward the tip. The inner peripheral surfaces of the first seal portion 33 and the second seal portion 34 rise substantially vertically in the vertical direction from the annular film portion 32. The first seal portion 33 and the second seal portion 34 are arranged symmetrically in the vertical direction.

[0049] In the unloaded state of the liquid-sealed vibration isolator 10, the first seal portion 33 contacts the intermediate portion 23b, and the second seal portion 34 contacts the outer peripheral portion 26b over the entire circumference. Therefore, the short-circuit path formed by the outer hole 24c, the accommodation space 29, and the through hole 27b is blocked by the valve 30.

[0050] This state where the short-circuit path is blocked is referred to as the state where the valve 30 is closed. In the state where the valve 30 is closed, the liquid does not move through the short-circuit path, and the liquid mainly moves through the orifice 19. Therefore, it is easy to exhibit the damping characteristics by the orifice 19.

[0051] On the other hand, when a large load (vibration with a large amplitude) is input to the liquid-sealed vibration isolator 10 and the first liquid chamber 17 is excessively depressurized as the vibration isolation base 13 deforms, the annular film portion 32 of the valve 30 is displaced (deformed) toward the first partition plate 23 side, and the first seal portion 33 is crushed. As a result, a gap is formed between the second seal portion 34 and the outer peripheral portion 26b in the vertical direction. As a result, the short-circuit path formed by the outer hole 24c, the accommodation space 29 (between the second seal portion 34 and the outer peripheral portion 26b, and between the valve 30 and the inner peripheral surface of the stepped portion 26c), and the through hole 27b communicates.

[0052] The state in which this short - circuit path is in communication is referred to as the state in which the valve 30 is open. When the valve 30 is open, since the liquid flows from the second liquid chamber 18 to the first liquid chamber 17 through the short - circuit path, the excessive negative pressure in the first liquid chamber 17 can be eliminated, and the cavitation associated with the negative pressure can be suppressed.

[0053] When the valve 30 opens, the liquid between the annular membrane portion 32 and the first partition plate 23 escapes to the first liquid chamber 17 through the inner hole 24b. As a result, the valve 30 including the annular membrane portion 32 can be quickly displaced toward the first partition plate 23 side, and the second seal portion 34 can be quickly separated from the outer peripheral portion 26b. Conversely, when the valve 30 closes, the liquid in the first liquid chamber 17 flows through the inner hole 24b between the annular membrane portion 32 and the first partition plate 23, so that the second seal portion 34 can be quickly brought into contact with the outer peripheral portion 26b. Thus, the inner hole 24b can improve the switching sensitivity of the opening and closing of the valve 30.

[0054] Also, when the first liquid chamber 17 is under positive pressure, since the second seal portion 34 is pressed against the second partition plate 26, the valve 30 closes in the same way as in the no - load state. Furthermore, since the liquid pressure from the first liquid chamber 17 is applied to the annular membrane portion 32 of the valve 30 through the inner hole 24b, the second seal portion 34 is pressed more strongly against the second partition plate 26. Therefore, it is difficult for the liquid to leak through the gap between the second seal portion 34 and the second partition plate 26.

[0055] In the present embodiment, the first seal portion 33 and the second seal portion 34 that switch the communication and interruption of the short - circuit path in this way are provided on the radially outer side with respect to the annular sandwiched portion 31 sandwiched between the first partition plate 23 and the second partition plate 26. Therefore, compared with the case where the first seal portion 33 and the second seal portion 34 are provided on the radially inner side with respect to the sandwiched portion 31, it is easier to increase the diameters of the first seal portion 33 and the second seal portion 34. As a result, it is easy to enlarge the outer hole 24c provided on the radially outer side of the first seal portion 33 and the through - hole 27b provided on the radially inner side of the second seal portion 34, so that it is easy to ensure the flow rate of the short - circuit path when the valve 30 is open.

[0056] Also, when the clamped portion 31 is provided radially outside the first seal portion 33 and the second seal portion 34, a plurality of connecting portions connecting them will cross the short - circuit path, and the flow rate of the short - circuit path will decrease. However, in the present embodiment, since the clamped portion 31 is not present radially outside the first seal portion 33 and the second seal portion 34 but is present radially inside, a plurality of connecting portions connecting them can be prevented from crossing the short - circuit path. As a result, the flow rate of the short - circuit path when the valve 30 is opened can be ensured.

[0057] Furthermore, since the first seal portion 33 and the second seal portion 34 are located radially outside the annular clamped portion 31, it is easy to provide other functions inside the clamped portion 31. In the present embodiment, as a specific other function, a characteristic tuning mechanism by the elastic membrane portion 40 is provided.

[0058] The elastic membrane portion 40 tends to bulge upward or downward in response to changes in the hydraulic pressures of the first liquid chamber 17 and the second liquid chamber 18. At this time, the valve 30 connected to the elastic membrane portion 40 is pulled radially inward. Due to this pulling, when the second seal portion 34 is displaced to the through - hole 27b, the short - circuit path cannot be blocked.

[0059] However, in the present embodiment, when the valve 30 tends to be displaced radially inward with respect to the first partition plate 23 and the second partition plate 26, the first inner convex portion 25b, the second inner convex portion 28b, and the inner steps 31c, 31d catch, so that the valve 30 can be made difficult to be displaced radially inward. As a result, even when the valve 30 is connected to the elastic membrane portion 40, the short - circuit path can be surely blocked by the valve 30 in a no - load state or the like.

[0060] Also, regardless of the tension from the elastic film portion 40, even if the valve 30 tends to shift radially with respect to the first partition plate 23 and the second partition plate 26, at any position in the circumferential direction, the first inner convex portion 25b, the second inner convex portion 28b, and the inner steps 31c, 31d catch on each other. Similarly, at any position in the circumferential direction, the first outer convex portion 25a, the second outer convex portion 28a, and the outer steps 31a, 31b catch on each other. As a result, it is possible to make it difficult for the valve 30 to shift radially, so that it is possible to suppress the first seal portion 33 from shifting to the outer hole 24c or the second seal portion 34 from shifting to the through hole 27b. Therefore, it is possible to suppress a decrease in the short-circuit path blocking performance due to the valve 30 caused by such a shift.

[0061] In particular, since the sandwiched portion 31 is accommodated between the first outer convex portion 25a and the first inner convex portion 25b and between the second outer convex portion 28a and the second inner convex portion 28b, it is possible to make it more difficult for the valve 30 to shift radially with respect to the first partition plate 23 and the second partition plate 26. As a result, it is possible to further suppress a decrease in the short-circuit path blocking performance due to the valve 30 caused by such a shift.

[0062] Since the annular film portion 32 of the valve 30 is sandwiched vertically between the first outer convex portion 25a and the second outer convex portion 28a, the valve 30 opens and closes by displacement (deformation) that rotates about the sandwiched portion as a fulcrum. As a result, the movement of the valve 30 during opening and closing is stabilized, so that it is easy to adjust the timing of its opening and closing.

[0063] When the first liquid chamber 17 is excessively depressurized, both the valve 30 and the elastic film portion 40 deform toward the first liquid chamber 17 side, and the vicinity of the sandwiched portion 31, which is the connecting portion between them, deforms in a substantially V shape in a cross section including the axis C. However, in addition to the annular film portion 32 being sandwiched vertically between the first outer convex portion 25a and the second outer convex portion 28a, the elastic film portion 40 is sandwiched vertically between the first inner convex portion 25b and the second inner convex portion 28b, so that the substantially V-shaped deformation can be made stepwise. As a result, it is possible to suppress the concentration of strain due to the substantially V-shaped deformation and improve the durability of the valve 30 and the elastic film portion 40.

[0064] Next, a second embodiment will be described with reference to FIGS. 3(a) and 3(b). In the first embodiment, the case where the first outward convex portion 25a is provided on the first partition plate 23 was described. In contrast, in the second embodiment, the case where the first outward convex portion 25a is not provided on the first partition plate 52 will be described. For the same parts as in the first embodiment, the same reference numerals are given and the following description will be omitted.

[0065] FIG. 3(a) is a partially enlarged cross-sectional view of the liquid-filled vibration isolator 50 in the unloaded state in the second embodiment. FIG. 3(b) is a partially enlarged cross-sectional view of the liquid-filled vibration isolator 50 when the valve 30 is open.

[0066] As shown in FIG. 3(a), the lower surface (the surface on the valve 30 side) of the first clamping portion 53 of the first partition plate 52 in the partition body 51 of the liquid-filled vibration isolator 50 includes a flat portion 54 facing the annular film portion 32. This flat portion 54 is formed flush with the portion of the lower surface of the first clamping portion 53 that contacts the clamped portion 31.

[0067] That is, on the lower surface of the first clamping portion 53, there is no first outward convex portion 25a of the first embodiment where the outer step 31a of the clamped portion 31 catches when the valve 30 tends to shift radially outward. The liquid-filled vibration isolator 50 of the second embodiment is the liquid-filled vibration isolator 10 of the first embodiment excluding the first outward convex portion 25a, and the rest is configured in the same manner as the first embodiment.

[0068] According to such a liquid-filled vibration isolator 50, as shown in FIG. 3(b), when the valve 30 opens so that the first seal portion 33 pressed against the first partition plate 52 is crushed and displaced toward the first liquid chamber 17 side, it is possible to prevent this displacement from being restricted by the first outward convex portion 25a. Therefore, the upper side of the clamped portion 31 pressed against the first partition plate 52 is also crushed, and the annular film portion 32 near the clamped portion 31 is displaced toward the flat portion 54 (the first liquid chamber 17 side). As a result, the gap between the second partition plate 26 and the second seal portion 34 can be increased, and the flow rate of the short-circuit path when the valve 30 is open can be increased.

[0069] In addition, when the valve 30 tends to shift radially with respect to the first partition plate 52 and the second partition plate 26, even if the outer step 31a does not catch on the flat portion 54, the outer step 31b catches on the second outer convex portion 28a on the opposite side in the vertical direction, so that the valve 30 can be made difficult to shift radially. Similarly, since the inner steps 31c and 31d catch on the first inner convex portion 25b and the second inner convex portion 28b, the valve 30 can be made difficult to shift radially.

[0070] Also, when the upper side of the clamped portion 31 is crushed and the valve 30 opens, since the first partition plate 52 has no first outer convex portion 25a, when the lower side of the clamped portion 31 comes out from between the second outer convex portion 28a and the second inner convex portion 28b, the clamped portion 31 may shift radially with respect to them. However, since the first partition plate 52 is provided with the first inner convex portion 25b that catches on the inner step 31c of the clamped portion 31, the valve 30 can be made difficult to shift radially even in such a case.

[0071] As described above, the present invention has been described based on the embodiments. However, the present invention is not limited to the above embodiments at all, and it can be easily inferred that various improvements and modifications are possible without departing from the gist of the present invention. For example, the number of the inner holes 24b, the outer holes 24c, the through holes 27b, etc. may be appropriately changed.

[0072] The first member 11 may be arranged at a position offset radially from the axis C. Also, the axis C of the second member 12 and the axis C of each part of the valve 30, the accommodation space 29, etc. may be offset. Each part of the valve 30, the accommodation space 29, etc. is not limited to the case of being annular, and may be formed in an annular shape such as a polygon, an ellipse, or an oblong. The formation position, length, etc. of the orifice 19 may be appropriately changed.

[0073] A cup-shaped cap fitting may be provided at the lower part of the diaphragm 15 (on the side opposite 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 cap fitting and the diaphragm 15. This air chamber may be made into a sealed space to have an air spring effect. A through hole may be provided in a part of the cap fitting to open the air chamber to the atmosphere, and a damping effect by the air passing through the through hole may be added to the liquid-filled vibration isolators 10 and 50.

[0074] In the above embodiment, an engine mount was exemplified as an application target of the liquid-filled vibration isolators 10 and 50, but the application target is arbitrary. Other application targets include, for example, motor mounts, member mounts, and differential mounts. Also, it is not limited to the case where the first member 11 is attached to the vibration source side such as an engine and the second member 12 is attached to the vibration receiving side such as a vehicle body. The second member 12 may be attached to the vibration source side and the first member 11 may be attached to the vibration receiving side.

[0075] In the above embodiment, the case where a part of the chamber wall of the first liquid chamber 17 is constituted by the vibration isolation base 13 and a part of the chamber wall of the second liquid chamber 18 is constituted by the diaphragm 15 was described, but it is not necessarily limited to this. For example, the second liquid chamber 18 may be referred to as the first liquid chamber, and the first liquid chamber 17 may be referred to as the second liquid chamber.

[0076] A part of the above embodiment may be omitted. For example, the film part 14 may be omitted, and the partition bodies 20 and 51 and the diaphragm 15 may be attached to the inner peripheral surface of the second member 12. The connecting part between the valve 30 and the elastic film part 40 may be omitted, and they may be independent. The first inner convex part 25b, the second outer convex part 28a, and the second inner convex part 28b may be omitted. The groove between the first outer convex part 25a and the first inner convex part 25b may be filled, or the groove between the second outer convex part 28a and the second inner convex part 28b may be filled, so that the outer steps 31a and 31b and the inner steps 31c and 31d may be omitted from the clamped part 31.

[0077] In the above-described embodiment, the case where the characteristic tuning mechanism by the elastic film portion 40 is provided inside the clamped portion 31 has been described. However, it is not necessarily limited to this, and other functions may be provided. For example, a liquid chamber different from the first liquid chamber 17 and the second liquid chamber 18 may be provided inside the clamped portion 31. An orifice for communicating between the two liquid chambers may be provided inside the clamped portion 31 separately from the orifice 19. A switching film for switching the communication and blocking of the orifice may be provided inside the clamped portion 31. A switching mechanism for actively changing the volume of the first liquid chamber 17 or the second liquid chamber 18 by an actuator or the like may be provided inside the clamped portion 31.

[0078] Also, the liquid-filled vibration isolator may be changed as shown in FIG. 4. FIG. 4 is a cross-sectional view of the left half of the partition body 60 of the liquid-filled vibration isolator in the modified example. The partition body 60 is assembled to the liquid-filled vibration isolator 10 in place of the partition body 20 in the first embodiment. The partition body 60 is obtained by omitting the elastic film portion 40 from the partition body 20 of the first embodiment and providing a partition portion 61 for closing the second central hole 27a on the second partition plate 26. In this way, by not providing anything inside the clamped portion 31, the partition body 60 can be easily reduced in weight and size.

[0079] In the above-described embodiment, the case where the first seal portion 33 is an annular shape continuous over the entire circumference has been described. However, it is not necessarily limited to this. For example, a plurality of the first seal portions 33 may be provided intermittently in the circumferential direction. In this case, since the liquid between the annular film portion 32 and the first partition plates 23 and 52 moves through between the plurality of the first seal portions 33, the inner hole 24b may be omitted. However, when the first seal portion 33 is an annular shape continuous over the entire circumference, the distortion generated in the valve 30 in the vicinity of the first seal portion 33 can be made uniform in the circumferential direction. As a result, the durability of the valve 30 can be improved.

[0080] In addition, the first outer convex portion 25a, the first inner convex portion 25b, the second outer convex portion 28a, and the second inner convex portion 28b may be provided intermittently in the circumferential direction, not limited to the case where they are continuous annular shapes extending over the entire circumference. However, when these convex portions are continuous annular shapes extending over the entire circumference, the distortion generated in the valve 30 and the elastic film portion 40 in the vicinity of the clamped portion 31 can be made uniform in the circumferential direction. As a result, the durability of the valve 30 and the elastic film portion 40 can be improved.

Explanation of Reference Numerals

[0081] 10, 50 Liquid-sealed vibration isolator 11 First member 12 Second member 13 Vibration isolation base 15 Diaphragm 17 First liquid chamber 18 Second liquid chamber 19 Orifice 20, 51, 60 Partition body 23, 52 First partition plate 24a First central hole 24c Outer hole (part of short circuit path) 25b First inner convex portion 26 Second partition plate 27a Second central hole 27b Through hole (part of short circuit path) 28a Second outer convex portion 28b Second inner convex portion 29 Accommodation space (part of short circuit path) 30 Valve 31 Clamped portion 31a, 31b Outer step 31c, 31d Inner step 32 Annular film portion 33 First seal portion 34 Second seal portion 40 Elastic film portion

Claims

1. a first member and a cylindrical second member; a vibration isolation base made of an elastic body that connects the first member and the second member; a diaphragm made of an elastic body attached to the second member and forming a liquid chamber in which a liquid is enclosed between the diaphragm and the vibration isolation base; a partition body that partitions the liquid chamber into a first liquid chamber and a second liquid chamber; an orifice that communicates the first liquid chamber and the second liquid chamber, and comprising: the partition body includes a first partition plate facing the first liquid chamber; a second partition plate facing the second liquid chamber and forming an annular accommodation space between the second partition plate and the first partition plate; a valve made of an elastic body sandwiched between the first partition plate and the second partition plate; the valve includes an annular clamped portion clamped by the first partition plate and the second partition plate over the entire circumference; an annular annular film portion extending radially outward from the clamped portion and protruding into the accommodation space; a first seal portion protruding from an outer edge portion of the annular film portion toward the first partition plate in the axial direction of the annular film portion; an annular second seal portion protruding from the entire circumference of the outer edge portion of the annular film portion toward the second partition plate in the axial direction; a plurality of outer holes communicating the first liquid chamber and the accommodation space are formed through the first partition plate radially outside the first seal portion; a plurality of through holes communicating the second liquid chamber and the accommodation space are formed through the second partition plate radially inside the second seal portion and radially outside the clamped portion; a short circuit path connecting the first liquid chamber and the second liquid chamber is formed by the outer holes, the through holes, and the accommodation space; the short circuit path is blocked by the first seal portion contacting the first partition plate and the second seal portion contacting the second partition plate over the entire circumference; a liquid-filled vibration isolation device, characterized in that the short circuit path communicates when the annular film portion is displaced toward the first liquid chamber side and the second seal portion separates from the second partition plate.

2. the clamped portion has outer steps rising from both sides in the axial direction from the annular film portion, and is formed thicker than the annular film portion in the axial direction; the surface of the first partition plate on the valve side is formed flush at the portion contacting the clamped portion and the portion facing the annular film portion; the liquid-filled vibration isolation device according to claim 1, wherein a second outward convex portion protruding toward the annular film portion is provided on the surface of the second partition plate on the valve side between the portion contacting the clamped portion and the through hole.

3. It is provided with a plate-shaped elastic film portion made of an elastic body having an outer peripheral edge connected to the inner peripheral edge of the clamped portion of the valve. The first partition plate is formed with a first central hole that exposes the elastic film portion to the first liquid chamber. The liquid-filled vibration isolator according to claim 1 or 2, wherein the second partition plate is formed with a second central hole that exposes the elastic film portion to the second liquid chamber at a position axially opposed to the first central hole.

4. It is provided with a plate-shaped elastic film portion made of an elastic body having an outer peripheral edge connected to the inner peripheral edge of the clamped portion of the valve. The first partition plate is formed with a first central hole that exposes the elastic film portion to the first liquid chamber. The second partition plate is formed with a second central hole that exposes the elastic film portion to the second liquid chamber at a position axially opposed to the first central hole. The inner peripheral edge of the clamped portion has inner stepped portions that rise from the outer peripheral edge of the elastic film portion to both sides in the axial direction. On the surface of the first partition plate on the valve side, a first inner convex portion that protrudes toward the elastic film portion is provided between the portion in contact with the clamped portion and the first central hole. The liquid-filled vibration isolator according to claim 2, wherein a second inner convex portion that protrudes toward the elastic film portion is provided on the surface of the second partition plate on the valve side between the portion in contact with the clamped portion and the second central hole.

Images