Liquid-filled vibration isolation device

Abstract

To provide a liquid-filled vibration isolation device that can suppress performance defects caused by liquid leakage from the orifice. [Solution] The pair of axial partitions (first partition 33 and second partition 34) have two or more recesses 39 that expose a portion of the circumferential edges on both sides of the connecting wall 42. Therefore, when the axial partition is molded in the mold 70 while embedding the connecting wall 42 in the axial partition made of an elastic material, a portion of the mold 70 is positioned at the location of these recesses 39. Thus, when the axial partition is molded, the circumferential edges on both sides of the connecting wall 42 come into contact with the portion of the mold 70 corresponding to the recesses 39, making it easier to position the connecting wall 42 circumferentially within the mold 70. As a result, the occurrence of leakage from the orifice 63 can be suppressed.

Description

Technical Field

[0001] The present invention relates to a liquid-sealed vibration isolator, and more particularly to a liquid-sealed vibration isolator capable of suppressing characteristic deterioration due to leakage of liquid from an orifice.

Background Art

[0002] Conventionally, for the purpose of vibration attenuation, buffering, etc., a liquid-sealed vibration isolator is disposed at a connection portion between a vibration source such as a wheel or an engine and a vehicle body. For example, in this liquid-sealed vibration isolator, an outer peripheral surface of an inner member and an inner peripheral surface of a cylindrical outer member are connected by a vibration isolation base body made of an elastic body. Between a pair of axial partitions of the vibration isolation base body, a space between the inner member and the outer member is partitioned in the circumferential direction to form a pair of liquid chambers. An orifice that communicates the pair of liquid chambers is formed by an outer peripheral groove provided on an outer peripheral surface of a pair of orifice forming members respectively disposed in the pair of liquid chambers and an inner peripheral surface of the outer member.

[0003] In the liquid-sealed vibration isolator disclosed in Patent Document 1, an elastic body (a part of the axial partition) is compressed in the circumferential direction between a part of an intermediate cylinder embedded in the axial partition and the orifice forming member. By the reaction force accompanying this compression, the orifice forming member is positioned in the circumferential direction.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] However, in the conventional technology described above, if the position of the intermediate cylinder shifts circumferentially within the axial partition, the circumferential free length of the elastic body sandwiched between the intermediate cylinder and the orifice forming member becomes smaller on one side relative to the intermediate cylinder and larger on the other side. On the smaller side, the pressing of the orifice forming member into the elastic body is restricted by the intermediate cylinder and becomes insufficient, while on the larger side, sufficient reaction force cannot be obtained, causing the orifice forming member to be pressed too far into the elastic body. In this case, a gap may form between the outer surface of the orifice forming member and the inner surface of the outer member, potentially causing leakage in the orifice. Consequently, this leakage may lead to performance defects in the liquid-filled vibration isolation device.

[0006] This invention was made to solve the above-mentioned problems, and aims to provide a liquid-filled vibration isolation device that can suppress performance defects caused by liquid leakage from the orifice. [Means for solving the problem]

[0007] To achieve this objective, the liquid-filled vibration damping device of the present invention comprises an inner member extending along an axis, a cylindrical outer member surrounding the inner member, an intermediate cylinder provided on the inner circumference side of the outer member, a pair of radial partitions formed by elastic bodies that connect the outer circumference of the inner member and the inner circumference of the outer member over their entire circumference and are spaced apart in the axial direction from each other, a pair of axial partitions made of elastic bodies that extend radially outward from the outer circumference of the inner member and contact the inner circumference of the outer member, thereby dividing the space surrounded by the inner member, the outer member and the pair of radial partitions in the circumferential direction to form a pair of liquid chambers, and a pair of orifice formations arranged in the pair of liquid chambers, with their outer surfaces contacting the inner circumference of the outer member. The intermediate cylinder comprises a member and an orifice formed by an outer peripheral groove provided on the outer peripheral surface of the orifice-forming member and the inner peripheral surface of the outer member, which connects a pair of liquid chambers, and the intermediate cylinder comprises a pair of peripheral walls provided on the outer peripheral surfaces of a pair of radial partition walls, and a pair of connecting walls extending radially inward from the peripheral walls, connecting the pair of peripheral walls to each other and embedded in each of the pair of axial partition walls, and the pair of axial partition walls has a compressible portion that is compressed in the circumferential direction between the connecting wall and the orifice-forming member, and two or more recesses are formed in the portion of the pair of axial partition walls other than the compressible portion, exposing a portion of the circumferential edges on both sides of the connecting wall over the entire thickness. [Effects of the Invention]

[0008] According to the liquid-filled vibration isolation device described in claim 1, each pair of axial partitions has two or more recesses formed therein that expose a portion of the circumferential edges on both sides of the connecting wall. Therefore, when the axial partition is formed in a mold while embedding the connecting wall of the intermediate cylinder into the axial partition made of an elastic material, a portion of the mold is positioned at the location of these recesses. Thus, when forming the axial partition, the circumferential edges on both sides of the connecting wall come into contact with the portion of the mold corresponding to the recess, making it easier to position the connecting wall circumferentially within the mold.

[0009] Furthermore, if, for example, about half the thickness of the circumferential edges of the connecting wall contacts a part of the mold, the connecting wall may ride up onto that part of the mold, potentially causing it to shift circumferentially from its original position. In contrast, since a portion of the circumferential edges of the connecting wall is exposed as a recess over its entire thickness, the entire thickness of the edge can be made to contact a part of the mold during the molding of the axial partition wall. This prevents the connecting wall from riding up onto a part of the mold, improving the circumferential positional accuracy of the connecting wall within the mold. As a result, the free length of the compressed portion of the axial partition wall that is compressed circumferentially between the connecting wall and the orifice forming member can be suppressed from fluctuating according to the circumferential position of the connecting wall. Consequently, fluctuations in the reaction force of the compressed portion acting on the orifice forming member can be suppressed, stabilizing the circumferential position of the orifice forming member and preventing orifice leakage associated with instability of its position.

[0010] Furthermore, since the recess is formed to avoid the compressed portion, the reduction in the reaction force from the compressed portion when compressed between the connecting wall and the orifice forming member can be suppressed. Therefore, the circumferential position of the orifice forming member can be further stabilized by ensuring the reaction force of the compressed portion, and the occurrence of orifice leakage due to instability in that position can be further suppressed.

[0011] The liquid-filled vibration isolation device according to claim 2 provides the following effects in addition to the effects of the liquid-filled vibration isolation device according to claim 1: One of a pair of axial partitions is a first partition and the other is a second partition. The orifice passes through the first partition and not through the second partition. If a recess is formed in the first partition, the size of the orifice may be limited by the recess. In contrast, by forming a recess in the second partition, the limitation of the orifice size by the recess can be suppressed, and the degree of freedom in its size can be improved.

[0012] The liquid-filled vibration isolation device according to claim 3 provides the following effects in addition to those of the liquid-filled vibration isolation device according to claim 2: The compressed portion is provided in at least the second partition wall, and the second partition wall comprises an outer groove and a recessed groove. The outer groove is provided on the radial end face of the second partition wall, which is axially outward from the compressed portion, and extends from the circumferential end face of the second partition wall toward the circumferential center. The recessed groove is provided on the radially opposite side of the connecting wall from the outer groove and is recessed toward the circumferential center from the circumferential end face of the second partition wall. These outer groove and recessed groove allow for the reduction of the volume of the elastic body in the liquid-filled vibration isolation device, thereby reducing the material cost of the elastic body and ensuring sufficient volume for the liquid chamber.

[0013] Furthermore, the recess is formed on the circumferential end face so as to connect the outer groove and the recessed groove in the radial direction. As a result, when the second partition wall is formed with a mold, the connecting wall is inserted radially between the molds that form the outer groove and the recessed groove, while the mold for the recess is provided along the entire length of that radial distance. This makes it almost certain that the connecting wall will not ride up onto the mold for the recess, thereby improving the circumferential positional accuracy of the connecting wall within the mold. As a result, the occurrence of orifice leakage due to variations in the position of the connecting wall can be further suppressed.

[0014] The liquid-filled vibration isolation device according to claim 4 provides the following effects in addition to those of the liquid-filled vibration isolation device according to claim 2: The portion to be compressed is provided at least in the second partition wall. The second partition wall is provided on the radial end face of the second partition wall located axially outward from the portion to be compressed, and includes outer grooves extending from the circumferential end face of the second partition wall toward the circumferential center. These outer grooves allow for the reduction of the volume of the elastic body in the liquid-filled vibration isolation device, thereby reducing the material cost of the elastic body and ensuring sufficient volume in the liquid chamber.

[0015] The connecting wall has an enlarged portion whose circumferential dimension gradually widens toward the pair of circumferential walls. The recess is provided at a position that exposes the circumferential edge of this enlarged portion. When forming the second partition wall with a mold, in order to accurately position the enlarged portion by bringing it into contact with the mold in the part that forms the recess, the larger the axial width of the contacting portion (recess), the higher the dimensional accuracy required of the mold. In contrast, since the axial width of the recess is smaller than that of the outer groove, the dimensional accuracy required of the mold in the part that forms the recess can be reduced, making it easier to manufacture the mold.

[0016] The liquid-filled vibration damping device described in claim 5 provides the following effects in addition to the effects of the liquid-filled vibration damping device described in any one of claims 1 to 4. Recesses that expose the circumferential edges on both sides of the connecting wall are provided on both sides in the axial direction relative to the compressed portion, forming a total of four or more recesses. When the axial partition wall is formed with a mold, a part of the mold is located at the position of these recesses, which increases the contact points between the circumferential edges of the connecting wall and the mold. This suppresses wear of the mold at the contact points and improves the durability of the mold. [Brief explanation of the drawing]

[0017] [Figure 1] This is a plan view of a liquid-filled vibration isolation device according to the first embodiment. [Figure 2] This is a front view of a liquid-filled vibration isolation device. [Figure 3] This is a cross-sectional view of a liquid-filled vibration isolation device along line III-III in Figure 1. [Figure 4] Figure 1 is a cross-sectional view of a liquid-filled vibration isolation device along line IV-IV. [Figure 5] Figure 2 is a cross-sectional view of a liquid-filled vibration isolation device on a VV line. [Figure 6] (a) is a cross-sectional view of the liquid-filled vibration damping device near the first partition after the drawing process, and (b) is a cross-sectional view of the liquid-filled vibration damping device near the second partition after the drawing process. [Figure 7] This is a front view of a liquid-filled vibration damping device with the outer components removed. [Figure 8]It is a side view of the second partition wall in the direction of arrow VII in FIG. 7. [Figure 9] It is a schematic diagram showing a method of manufacturing a liquid-sealed vibration isolator, including an end face view of a cut portion of an inner member and an intermediate cylinder on line IX-IX in FIG. 7. [Figure 10] It is a schematic diagram showing a method of manufacturing a liquid-sealed vibration isolator, including an end face view of a cut portion of an inner member and an intermediate cylinder on line X-X in FIG. 7. [Figure 11] It is a rear view of a liquid-sealed vibration isolator with the outer member removed in the second embodiment. [Figure 12] It is a side view of the liquid-sealed vibration isolator in the direction of arrow XII in FIG. 11.

Embodiments for Carrying Out the Invention

[0018] Hereinafter, preferred embodiments will be described with reference to the accompanying drawings. FIG. 1 is a plan view of a liquid-sealed vibration isolator 1 in the first embodiment. FIG. 2 is a front view of the liquid-sealed vibration isolator 1. Arrows U, D, L, R, F, and B in each drawing indicate the upward, downward, leftward, rightward, forward, and rearward directions of the liquid-sealed vibration isolator 1, respectively. Note that the up-down direction, left-right direction, and front-rear direction of this liquid-sealed vibration isolator 1 do not necessarily coincide with the up-down direction, left-right direction, and front-rear direction of a vehicle or the like on which the liquid-sealed vibration isolator 1 is mounted.

[0019] The liquid-sealed vibration isolator 1 mainly includes a substantially cylindrical inner member 10 extending along an axis C, a substantially cylindrical outer member 20 concentrically surrounding the outer peripheral side of the inner member 10, and a vibration isolation base 30 connecting the inner member 10 and the outer member 20. The axial direction of the axis C is the up-down direction. 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.

[0020] The inner member 10 is a member formed from a rigid material such as a steel material or an aluminum alloy. The inner member 10 is fixed to the mating member by bolts inserted on the inner peripheral surface side of the inner member 10. The outer member 20 is press-fitted and fixed to another mating member.

[0021] Figure 3 is a cross-sectional view of the liquid-filled vibration isolation device 1 along the line III-III in Figure 1. Figure 4 is a cross-sectional view of the liquid-filled vibration isolation device 1 along the line IV-IV in Figure 1. Figure 5 is a cross-sectional view of the liquid-filled vibration isolation device 1 along the line VV in Figure 2. In Figure 3, the upper surface of the orifice forming member 51 and the lower surface of the orifice forming member 52 are shown by dashed lines.

[0022] As shown in Figure 3, the outer member 20 comprises a substantially cylindrical tube portion 21 formed from a rigid material such as steel or aluminum alloy, and an elastic film 22 made of an elastic material such as rubber or thermoplastic elastomer, which is vulcanized and bonded to the inner circumferential surface of the tube portion 21. The elastic film 22 forms the inner circumferential surface 23 of the outer member 20. An intermediate cylinder 40, provided on the inner circumferential side of the outer member 20, is fitted onto this inner circumferential surface 23 of the outer member 20. The outer member 20 is crimped and fixed to the intermediate cylinder 40 by bending its axial edge radially inward.

[0023] The vibration-damping base 30 is a component made of an elastic material such as rubber or thermoplastic elastomer, and connects the outer circumferential surface of the inner member 10 and the inner circumferential surface of the outer member 20. The vibration-damping base 30 comprises a pair of annular radial partition walls 31 formed on both the axial sides of the inner member 10 and the outer member 20, and an elastic stopper 32 formed between the radial partition walls 31. The radial partition walls 31 and the elastic stopper 32 are integrally vulcanized and molded, and the inner circumferences of the radial partition walls 31 and the elastic stopper 32 are vulcanized and bonded to the outer circumferential surface of the inner member 10.

[0024] The outer surface of the radial partition wall 31 is vulcanized and bonded to the inner circumference of the peripheral wall 41 of the intermediate cylinder 40 that concentrically surrounds the inner member 10. The axial ends between the inner member 10 and the outer member 20 are closed all around by the pair of radial partition walls 31, thereby forming the first liquid chamber 61 and the second liquid chamber 62. The first liquid chamber 61 and the second liquid chamber 62 are filled with an antifreeze (liquid) such as ethylene glycol.

[0025] As shown in Figures 4 and 5, the intermediate cylinder 40 comprises a pair of ring-shaped peripheral walls 41 that fit onto the inner circumferential surface 23 of the outer member 20, and a pair of connecting walls 42 that extend radially inward from the peripheral walls 41 and connect the pair of peripheral walls 41 to each other. The pair of connecting walls 42 are positioned on both the front and rear sides of the inner member 10, and their cross-section perpendicular to the axis C is formed in an arc shape.

[0026] The connecting wall 42 comprises a central portion extending substantially parallel to the axis C, and expanded portions 42a extending diagonally radially outward from both axial ends of the central portion and connected to the peripheral wall 41. The circumferential dimension of the central portion of the connecting wall 42 is substantially constant in the axial direction. The circumferential dimension of the expanded portions 42a gradually widens toward the peripheral wall 41 (see Figure 7).

[0027] A pair of first partition walls 33 and second partition walls 34 (axial partition walls), which are integrally vulcanized and molded with the radial partition wall 31, are vulcanized and bonded to the inner circumferential surfaces of the pair of connecting walls 42. In addition, the first partition walls 33 and second partition walls 34 are also provided so as to wrap around the outer circumferential surface of the connecting wall 42, and the first partition walls 33 and second partition walls 34 are vulcanized and bonded to the outer circumferential surface of the connecting wall 42. In other words, the pair of connecting walls 42 are embedded in the first partition walls 33 and second partition walls 34, respectively. The portion of the first partition walls 33 and second partition walls 34 into which the connecting wall 42 is embedded extends circumferentially along the connecting wall 42.

[0028] The first partition wall 33 is a portion extending radially outward and rearward from the outer circumferential surface of the inner member 10, and connects the pair of radial partition walls 31 in the axial direction. The second partition wall 34 is a portion extending radially outward and forward from the outer circumferential surface of the inner member 10, and connects the pair of radial partition walls 31 in the axial direction.

[0029] The first partition wall 33 includes a radial end face 33a that contacts the inner circumferential surface 23 of the outer member 20, and a pair of circumferential end faces 33b that extend radially inward from both circumferential edges of the radial end face 33a. A communication groove 33c that is recessed radially inward is formed in the axial center of the radial end face 33a of the first partition wall 33. The communication groove 33c is formed along the entire circumferential length of the first partition wall 33 so as to open into the pair of circumferential end faces 33b. The outer circumferential surface of the connecting wall 42 is exposed at the bottom of the communication groove 33c. In addition, the first partition wall 33 has a recessed groove portion 37 that is recessed toward the circumferential center from the circumferential end face 33b that is radially inward from the connecting wall 42.

[0030] The second partition wall 34 includes a radial end face 34a that contacts the inner circumferential surface 23 of the outer member 20, and a pair of circumferential end faces 34b that extend radially inward from the circumferential edges on both sides of the radial end face 34a. A central groove 35 that is recessed radially inward is formed in the axial center of the radial end face 34a of the second partition wall 34. The central groove 35 is a pair of left and right grooves that extend from the circumferential end faces 34b of the pair of second partition walls 34 toward the circumferential center, and are separated from each other. In addition, the second partition wall 34 has a recessed groove portion 38 that is recessed toward the circumferential center from the circumferential end face 34b that is radially inward from the connecting wall 42.

[0031] The space enclosed by the inner member 10, the outer member 20, and the pair of radial partition walls 31 is divided circumferentially by the first partition wall 33 and the second partition wall 34 to form the first liquid chamber 61 and the second liquid chamber 62. The first liquid chamber 61 and the second liquid chamber 62 are opposite each other with the inner member 10 in between, and are formed substantially symmetrically. The first liquid chamber 61 is located to the left of the first partition wall 33 and the second partition wall 34, and the second liquid chamber 62 is located to the right of the first partition wall 33 and the second partition wall 34.

[0032] As shown in Figures 3 and 5, a pair of orifice-forming members 51 and 52 are arranged between the inner member 10 and the outer member 20. The orifice-forming members 51 and 52 are members for forming an orifice 63 that connects the first liquid chamber 61 and the second liquid chamber 62.

[0033] The orifice-forming members 51 and 52 are formed in a substantially semi-circular shape from metal or synthetic resin. The orifice-forming member 51 is placed in the first liquid chamber 61, and the orifice-forming member 52 is placed in the second liquid chamber 62.

[0034] One circumferential end 54 (rear end) of the pair of orifice-forming members 51 and 52 fits into the communication groove 33c of the first partition wall 33, and they face each other directly in the circumferential direction within the communication groove 33c. The other circumferential end 55 (front end) of the pair of orifice-forming members 51 and 52 fits into the central groove 35 of the second partition wall 34, and a part of the second partition wall 34 is interposed between them so that they do not face each other directly. In this way, the orifice-forming members 51 and 52 are assembled to the vibration-damping base 30 which is vulcanized and bonded to the inner member 10, and the outer circumferential surfaces of the orifice-forming members 51 and 52 contact the inner circumferential surface 23 of the outer member 20 over substantially the entire circumference.

[0035] An outer peripheral groove 53 is formed on the outer peripheral surfaces of a pair of orifice-forming members 51 and 52, opening at one end 54 and connecting to each other. By bringing the outer peripheral surfaces of the orifice-forming members 51 and 52, on which the outer peripheral groove 53 is formed, into contact with the inner peripheral surface 23 of the outer member 20, an orifice 63 is formed between the outer peripheral groove 53 and the inner peripheral surface 23. The outer peripheral groove 53 opens on the upper surface of the central part of the circumferential portion of the orifice-forming member 51, allowing the orifice 63 to communicate with the first liquid chamber 61. The outer peripheral groove 53 opens on the lower surface of the central part of the circumferential portion of the orifice-forming member 52, allowing the orifice 63 to communicate with the second liquid chamber 62. The orifice 63 passes through the first partition wall 33 without passing through the second partition wall 34.

[0036] When a load is applied in the left-right direction to the liquid-filled vibration isolation device 1, the radial partition wall 31, the first partition wall 33, and the second partition wall 34 undergo elastic deformation, causing relative displacement between the inner member 10 and the outer member 20. This elastic deformation causes fluid pressure fluctuations in the first liquid chamber 61 and the second liquid chamber 62, and the liquid in the first liquid chamber 61 and the second liquid chamber 62 flows through the orifice 63. Liquid column resonance occurs through the orifice 63, and the vibration is damped. The damping characteristics of the orifice 63 are adjusted by the length of the flow path and the cross-sectional area of ​​the flow path of the orifice 63.

[0037] To manufacture such a liquid-filled vibration damping device 1, first, the inner member 10 and the intermediate cylinder 40 are set in a mold 70 (see Figures 9 and 10), the vibration damping base 30 is vulcanized and molded, and the inner member 10 and the intermediate cylinder 40 are vulcanized and bonded to the vibration damping base 30. Details of this vulcanization molding will be described later.

[0038] Next, the vulcanized molded product, the orifice forming members 51 and 52, and the outer member 20 are submerged in liquid. Then, the orifice forming members 51 and 52 are assembled to the vulcanized molded product and inserted into the inner circumferential surface 23 side of the outer member 20. After that, the outer member 20 is reduced in diameter by drawing and pressed against the outer circumferential surface 23 of the outer member 20 against the outer circumferential surface 23 of the orifice forming members 51 and 52. Finally, the axial edge of the outer member 20 is bent radially inward and the outer member 20 is crimped and fixed to the intermediate cylinder 40. This gives rise to the liquid-filled vibration damping device 1.

[0039] Figures 1-5 show the liquid-filled vibration damping device 1 before the drawing process. In contrast, Figure 6(a) is a cross-sectional view of the liquid-filled vibration damping device 1 near the first partition wall 33 after the drawing process. Figure 6(b) is a cross-sectional view of the liquid-filled vibration damping device 1 near the second partition wall 34 after the drawing process.

[0040] As shown in Figure 5, the orifice forming member 51 includes a first opposing surface 51a facing the circumferential end surface 33b of the first partition wall 33, and a second opposing surface 51b facing the circumferential end surface 34b of the second partition wall 34. The orifice forming member 52 includes a first opposing surface 52a facing the circumferential end surface 33b of the first partition wall 33, and a second opposing surface 52b facing the circumferential end surface 34b of the second partition wall 34.

[0041] The first opposing surfaces 51a, 52a and the second opposing surfaces 51b, 52b are all formed in a substantially planar shape and are separated from the circumferential end surfaces 33b, 34b before the drawing process. One end 54 protrudes from the first opposing surfaces 51a, 52a, and the other end 55 protrudes from the second opposing surfaces 51b, 52b, respectively.

[0042] As shown in Figure 6(a), the drawing process causes one end 54 of the pair of orifice-forming members 51 and 52 to abut against each other. Furthermore, the drawing process presses the first opposing surfaces 51a and 52a against the circumferential end surface 33b, respectively. At this time, a portion of the elastic body of the first partition wall 33 is compressed in the circumferential direction between the first opposing surfaces 51a and 52a of the orifice-forming members 51 and 52 and the connecting wall 42 of the intermediate cylinder 40. Of the elastic body compressed in this way, the side on the orifice-forming member 51 is designated as the compressed portion 33d, and the side on the orifice-forming member 52 is designated as the compressed portion 33e. Due to the reaction force accompanying the compression of the compressed portions 33d and 33e, the end 54 side of the orifice-forming members 51 and 52 is positioned in the circumferential direction relative to the first partition wall 33.

[0043] As shown in Figure 5, projections 33f extend from the circumferential end face 33b, continuing around the communication groove 33c. Through the drawing process, these projections 33f are pressed against and crushed by the first opposing surfaces 51a and 52a of the orifice forming members 51 and 52, thereby sealing the space between the circumferential end face 33b and the first opposing surfaces 51a and 52a. This prevents the liquid in the first liquid chamber 61 and the second liquid chamber 62 from leaking through the gap between the wall surface of the communication groove 33c and one end 54 of the orifice forming members 51 and 52.

[0044] As shown in Figure 6(b), the drawing process presses the second opposing surfaces 51b and 52b of the pair of orifice-forming members 51 and 52 against the circumferential end surface 34b, respectively. At this time, a portion of the elastic body of the second partition wall 34 is compressed in the circumferential direction between the second opposing surfaces 51b and 52b of the orifice-forming members 51 and 52 and the connecting wall 42 of the intermediate cylinder 40. Of the elastic body compressed in this way, the side on the orifice-forming member 51 is designated as the compressed portion 34d, and the side on the orifice-forming member 52 is designated as the compressed portion 34e. Due to the reaction force accompanying the compression of the compressed portions 34d and 34e, the other end 55 side of the orifice-forming members 51 and 52 is positioned in the circumferential direction relative to the second partition wall 34.

[0045] However, if the position of the connecting wall 42 shifts circumferentially from the circumferential center within the first partition wall 33 and the second partition wall 34, the free lengths of the compressed portions 33d, 33e, 34d, and 34e will change. For example, if the connecting wall 42 shifts clockwise from the state shown in Figure 5, the free lengths of the compressed portions 33e and 34d will decrease, and the free lengths of the compressed portions 33d and 34e will increase.

[0046] Consequently, on the side with a small free length, the pushing of the orifice-forming members 51 and 52 into the compressed portions 33e and 34d is restricted by the connecting wall 42 before sufficient reaction force can be obtained from the compressed portions 33e and 34d, resulting in insufficient pushing. On the side with a large free length, sufficient reaction force cannot be obtained from the compressed portions 33d and 34e, causing the orifice-forming members 51 and 52 to be pushed too far into the compressed portions 33d and 34e. In these cases, the outer circumferential surfaces of the orifice-forming members 51 and 52 are no longer located on the cylindrical surface centered on axis C, and a partial gap is created between their outer circumferential surfaces and the inner circumferential surface 23 of the outer member 20, potentially causing leakage in the orifice 63. Therefore, this leakage may result in performance defects in the liquid-filled vibration isolation device 1.

[0047] Next, with reference to Figures 7 to 10, a configuration for suppressing this characteristic defect will be described. Figure 7 is a front view of the liquid-filled vibration isolation device 1 with the outer member 20 removed. In Figure 7, the outline of the connecting wall 42 embedded in the second partition wall 34 is shown by a dashed line. Figure 8 is a side view of the vicinity of the central groove 35 of the second partition wall 34 in the direction of arrow VII in Figure 7. Figure 9 is a schematic diagram showing the manufacturing method of the liquid-filled vibration isolation device 1, including a cross-section end view of the connecting wall 42 of the inner member 10 and the intermediate cylinder 40 along the line IX-IX in Figure 7. Figure 10 is a schematic diagram showing the manufacturing method of the liquid-filled vibration isolation device 1, including a cross-section end view of the connecting wall 42 of the inner member 10 and the intermediate cylinder 40 along the line XX in Figure 7.

[0048] As shown in Figures 7 and 8, the second partition wall 34 is formed approximately symmetrically with respect to the center in the circumferential direction (left-right direction). Hereinafter, the second partition wall 34 will be described mainly from the side with the orifice forming member 52 (right side), and the description of the side with the orifice forming member 51 (left side) will be partially omitted.

[0049] The radial end face 34a of the second partition wall 34 has three grooves formed therein, which extend parallel to each other from the circumferential end face 34b toward the circumferential center and are recessed radially inward. Of these three grooves, the axial central groove is the central groove 35 into which the other ends 55 of the orifice forming members 51 and 52 fit, as described above.

[0050] Of the three grooves, the grooves located on both sides in the axial direction relative to the central groove 35 are the outer grooves 36. The outer grooves 36 are provided on the radial end faces 34a that are axially outward from the compressed portions 34d and 34e. Similar to the pair of central grooves 35 that are spaced apart in the circumferential direction, the four outer grooves 36 are also spaced apart from each other in the circumferential direction.

[0051] The outer groove 36 is a portion that reduces the volume of the second partition wall 34 (elastic body) radially outward from the connecting wall 42, thereby securing the volumes of the first liquid chamber 61 and the second liquid chamber 62. Similarly, the recessed grooves 37 and 38 provided in the first partition wall 33 and the second partition wall 34 radially inward from the connecting wall 42 are portions that reduce the volume of their respective elastic bodies, thereby securing the volumes of the first liquid chamber 61 and the second liquid chamber 62, respectively.

[0052] These external grooves 36 and recessed grooves 37, 38 allow for the reduction of the volume of the elastic body in the liquid-filled vibration isolation device 1, thereby reducing the material cost of the elastic body. The portion where the elastic body has been reduced is filled with an antifreeze (liquid) such as ethylene glycol, and since the material cost of this liquid is cheaper than that of the elastic body, the material cost of the liquid-filled vibration isolation device 1 can be reduced. Furthermore, the damping characteristics of the liquid-filled vibration isolation device 1 can be adjusted by adjusting the volume of the first liquid chamber 61 and the second liquid chamber 62 using the external grooves 36 and recessed grooves 37, 38.

[0053] The radially inner groove bottom of the central groove 35 is located radially deeper than the radially inner groove bottom of the outer groove 36. A portion of the outer surface of the connecting wall 42 is exposed at the groove bottom of the central groove 35. Furthermore, by partially removing the corner between the groove bottom of the central groove 35 and the circumferential end face 34b, the circumferential edge of the connecting wall 42 is partially exposed at that corner. At this corner, about half the thickness of the edge of the connecting wall 42 is exposed.

[0054] Furthermore, the second partition wall 34 has a recess 39 that exposes a portion of the circumferential edge of the enlarged portion 42a of the connecting wall 42 over its entire thickness. The recess 39 is a portion that is recessed in the circumferential direction relative to the circumferential end face 34b and is formed in the shape of a groove that connects the outer groove portion 36 and the recessed groove portion 38 in the radial direction. The bottom of this groove 39 and the circumferential edge of the connecting wall 42 are on the same plane, so the connecting wall 42 is exposed at the bottom of the groove 39.

[0055] The axial width of the recess 39 is smaller than the axial width of the outer groove 36 and the axial width of the central groove 35, for example, about half or less of their widths. Furthermore, the recess 39 is provided in the second partition wall 34 in a location other than the compression-reduced portions 34d and 34e. Specifically, a total of four recesses 39 are formed by providing approximately symmetrical recesses on both sides of the circumferential direction of the second partition wall 34, on both sides of the axial direction relative to the compression-reduced portions 34d and 34e.

[0056] As shown in Figures 9 and 10, the vibration-damping base 30 having such a recess 39 is vulcanized by a mold 70. The mold 70 includes a fixed mold (not shown) that forms the upper surface of the vibration-damping base 30, a movable mold (not shown) that forms the lower surface of the vibration-damping base 30, a sliding mold 71 that forms the left half of the outer circumferential surface of the vibration-damping base 30, and a sliding mold 72 that forms the right half of the outer circumferential surface of the vibration-damping base 30. Alternatively, the lower surface of the vibration-damping base 30 may be formed with the fixed mold and the upper surface with the movable mold.

[0057] To vulcanize the vibration-damping base 30, first the inner member 10 and the intermediate cylinder 40 are set in a fixed mold. Next, the movable mold is moved toward the fixed mold, and the inner member 10 is sandwiched between them. In addition, the slide molds 71 ​​and 72 are moved toward each other between the fixed mold and the movable mold, and the mold 70 is clamped by bringing them into contact with each other. Inside the clamped mold 70, a cavity 70a is formed that conforms to the outer shape of the vibration-damping base 30. By filling this cavity 70a with an elastic material and performing vulcanization molding (hardening), the vibration-damping base 30 with the intermediate cylinder 40 embedded is vulcanized, and the vibration-damping base 30 is vulcanized and bonded to the inner member 10. Finally, by opening the mold 70, a vulcanized molded product consisting of the inner member 10, the intermediate cylinder 40, and the vibration-damping base 30 is obtained.

[0058] The slide-type molds 71 ​​and 72 include a first partition-forming section 73 that forms a first partition wall 33 within the cavity 70a, and a second partition-forming section 74 that forms a second partition wall 34 within the cavity 70a. In Figures 9 and 10, the first partition-forming section 73 is shown by a dashed line along the outer shape (radial end face 33a and circumferential end face 33b) of the first partition wall 33 when the communication groove 33c and recessed groove section 37 are omitted. Similarly, in Figures 9 and 10, the second partition-forming section 74 is shown by a dashed line along the outer shape (radial end face 34a and circumferential end face 34b) of the second partition wall 34 when the central groove 35, outer groove section 36, recessed groove section 38, and recessed section 39 are omitted.

[0059] From the first partition wall forming section 73, a communication groove forming section 75 that forms the communication groove 33c and a recessed groove forming section 76 that forms the recessed groove section 37 each protrude toward the internal space. From the second partition wall forming section 74, a central groove forming section 77 that forms the central groove 35, a recessed groove forming section 78 that forms the recessed groove section 38, an outer groove forming section 79 that forms the outer groove section 36, and a recess forming section 80 that forms the recess 39 each protrude toward the internal space.

[0060] The shape, dimensions, and arrangement of each of these formed parts 75-80 are the same as the shape, dimensions, and arrangement of the parts 33c, 35-39 that they each form. Therefore, when the vibration-damping base 30 is formed (with the mold 70 clamped), a portion of the axial direction on the outer circumferential surface of the rear connecting wall 42 contacts the communication groove forming part 75 over its entire circumference. In addition, a portion of the axial direction on the outer circumferential surface of the front connecting wall 42 contacts the central groove forming part 77 over predetermined ranges on both sides in the circumferential direction. As a result, the connecting wall 42 is positioned radially (front-back, left-right, and right-back directions) within the mold 70. However, this alone may cause the connecting wall 42 to rotate around axis C.

[0061] In the central groove forming section 77, a stepped section 77a is formed, in which a portion of the circumferentially outer edge of the connecting wall 42 protrudes radially inward, exposing about half the thickness of the edge of the connecting wall 42 from the second partition wall 34. During the molding of the vibration-damping base 30, the circumferentially outer edges of the connecting wall 42 come into contact with this stepped section 77a. This allows the connecting wall 42 to rotate around axis C within the mold 70, that is, the connecting wall 42 can be positioned circumferentially within the mold 70.

[0062] However, since only about half the thickness of the circumferential edges of the connecting wall 42 are in contact with the stepped portion 77a, there is a risk that the connecting wall 42 may ride up onto one side of the stepped portion 77a when the mold is clamped after the intermediate cylinder 40 has been set in the fixed mold. This riding up may cause the connecting wall 42 to shift circumferentially from its original position (the circumferential center within the second partition forming portion 74 (second partition 34)).

[0063] However, in this embodiment, a recess-forming portion 80 (recess 39) is formed so that the entire thickness of the edge of the connecting wall 42 is exposed from the second partition wall 34. When the vibration-damping base 30 is molded, the edges on both sides in the circumferential direction of the connecting wall 42 come into contact with this recess-forming portion 80 over their entire thickness. This prevents the connecting wall 42 from riding up onto the recess-forming portion 80, and, similar to the stepped portion 77a, prevents the connecting wall 42 from rotating around axis C within the mold 70. Therefore, the circumferential positional accuracy of the connecting wall 42 within the mold 70 can be improved.

[0064] As described above, the liquid-filled vibration isolation device 1, which includes a vulcanized vibration isolation base 30, can suppress fluctuations in the free length of the compressed portions 33d, 33e, 34d, and 34e according to the circumferential position of the connecting wall 42. As a result, fluctuations in the reaction forces of the compressed portions 33d, 33e, 34d, and 34e acting on the orifice forming members 51 and 52 can be suppressed, and the circumferential position of the orifice forming members 51 and 52 can be stabilized. Therefore, the occurrence of leakage of the orifice 63 due to instability of its position can be suppressed.

[0065] The recess 39 formed by the stabilizing recess-forming portion 80 is formed to avoid the compressible portions 34d and 34e of the second partition wall 34. Therefore, the reduction in the reaction force from the compressible portions 34d and 34e during circumferential compression can be suppressed by the recess 39. Thus, by securing the reaction force from the compressible portions 34d and 34e, the circumferential positions of the orifice-forming members 51 and 52 can be further stabilized, and the occurrence of leakage from the orifice 63 due to instability in their position can be further suppressed.

[0066] The recess 39 may also be formed in the first partition wall 33, as in the second embodiment described later. However, in this case, since the orifice 63 is formed to pass through the first partition wall 33, the size (axial width) of the orifice 63 may be limited in order to secure space for the recess 39. In contrast, in this embodiment, the recess 39 is formed in the second partition wall 34, through which the orifice 63 does not pass, so the limitation of the size of the orifice 63 by the recess 39 can be suppressed, and the degree of freedom of its size can be improved.

[0067] The recess 39 is formed on the circumferential end face 34b so as to connect the outer groove 36 and the recessed groove 38 in the radial direction. As a result, when the vibration-damping base 30 is vulcanized, the connecting wall 42 is inserted radially between the recessed groove forming portion 78 and the outer groove forming portion 79, and the recess forming portion 80 is provided along the entire length of that radial distance. This makes it almost certain that the connecting wall 42 will not ride up onto the recess forming portion 80, thereby improving the circumferential positional accuracy of the connecting wall 42 within the mold 70. As a result, the occurrence of leakage from the orifice 63 due to variations in the position of the connecting wall 42 can be further suppressed.

[0068] The recess 39 is provided at a position that exposes the circumferential edge of the enlarged portion 42a of the connecting wall 42. Therefore, during the vulcanization molding of the vibration-damping base 30, the enlarged portion 42a is brought into contact with the recess forming portion 80 to position it in the circumferential direction. Here, as the circumferential dimension of the enlarged portion 42a gradually widens toward the circumferential wall 41, the edge of the enlarged portion 42a is inclined with respect to the axis C when viewed in the front-rear direction.

[0069] When the recess-forming portion 80 is brought into contact with the edge of the inclined enlarged portion 42a in this manner, if the edge of the enlarged portion 42a and the recess-forming portion 80 are not parallel in a view in the front-to-back direction, they will come into contact at one point on the upper or lower end in the axial direction. Furthermore, the wider the recess-forming portion 80, the greater the circumferential displacement of the enlarged portion 42a when contact occurs on the upper end side versus the lower end side. In other words, in order to accurately position the recess-forming portion 80 in the circumferential direction when it comes into contact with the edge of the inclined enlarged portion 42a, the wider the recess-forming portion 80 (recess 39), the higher the dimensional accuracy required of the recess-forming portion 80 so that the contacting parts are approximately parallel to each other.

[0070] In contrast, the recess 39 (recess-forming portion 80) has a sufficiently small axial width, smaller than, for example, the axial width of the outer groove 36 (outer groove-forming portion 79) or the central groove 35 (central groove-forming portion 77). Therefore, the dimensional accuracy required for the recess-forming portion 80 that forms the recess 39 can be reduced, making it easier to manufacture the mold 70 including the recess-forming portion 80.

[0071] Furthermore, for the purpose of positioning the connecting wall 42 in the circumferential direction, it is sufficient to have at least one recess 39 (recess-forming portion 80) on each side of the connecting wall 42 in the circumferential direction. In this embodiment, recesses 39 are provided on both sides in the axial direction relative to the compression portions 34d and 34e on each side of the second partition wall 34 in the circumferential direction. Therefore, during the vulcanization molding of the vibration-damping base 30, the number of contact positions between the circumferential edges of the connecting wall 42 and the recess-forming portion 80 can be increased to four. This suppresses wear of the recess-forming portion 80 at these contact positions and improves the durability of the mold 70 including the recess-forming portion 80.

[0072] Furthermore, the volume of the elastic body constituting the vibration-damping base 30 can be reduced by the amount of the recess 39, thereby reducing the material cost of the elastic body. Also, since the recess 39 is provided substantially symmetrically on both sides in the axial direction with respect to the compressed portions 34d and 34e, the way in which the compressed portions 34d and 34e elastically deform when the orifice forming members 51 and 52 are pressed against them can be made substantially symmetrical in the axial direction. This makes it easier to homogenize the reaction force of the compressed portions 34d and 34e on both sides in the axial direction. As a result, tilting of the orifice forming members 51 and 52 in the axial direction can be suppressed, and leakage of the orifice 63 associated with that tilt can be suppressed.

[0073] Next, a second embodiment will be described with reference to Figures 11 and 12. In the second embodiment, a case will be described in which a recess 91 is provided in the first partition wall 33 instead of the recess 39 in the second partition wall 34. Note that parts identical to those in the first embodiment are denoted by the same reference numerals and their descriptions will be omitted below.

[0074] Figure 11 is a rear view of the liquid-filled vibration isolation device 90 with the outer member 20 removed in the second embodiment. Figure 12 is a side view of the liquid-filled vibration isolation device 90 viewed in the direction of arrow XII in Figure 11. The liquid-filled vibration isolation device 90 is the same as the liquid-filled vibration isolation device 1 in the first embodiment, except that the recess 39 is omitted and a recess 91 is provided instead.

[0075] The recess 91 is formed in the first partition wall 33 such that a portion of the circumferential edge of the enlarged portion 42a of the connecting wall 42 is exposed over its entire thickness. The recess 91 is a portion that is recessed in the circumferential direction relative to the circumferential end face 33b of the first partition wall 33, and is formed as a groove that opens to the radial end face 33a of the first partition wall 33 and communicates with the recessed groove portion 37. The bottom of the groove of the recess 91 and the circumferential edge of the connecting wall 42 are on the same plane, so the connecting wall 42 is exposed at the bottom of the groove of the recess 91.

[0076] The recesses 91 are provided in the parts of the first partition wall 33 other than the compression portions 33d and 33e. Specifically, a total of four recesses 91 are formed by providing them approximately symmetrically on both sides in the axial direction relative to the compression portions 33d and 33e on each of the circumferential sides of the first partition wall 33.

[0077] When the first partition wall 33 (vibration-damping base 30) having such a recess 91 is vulcanized, a part of the mold 70 is positioned at the location of the recess 91, similar to the first embodiment. Therefore, during vulcanization, the circumferential edges on both sides of the connecting wall 42 come into contact with the part of the mold corresponding to the recess 91, making it easier to position the connecting wall 42 circumferentially within the mold 70.

[0078] In particular, since a portion of the circumferential edges on both sides of the connecting wall 42 is exposed by recesses 91 over its entire thickness, the entire thickness of these edges can be brought into contact with a portion of the mold 70 during vulcanization molding. This prevents the connecting wall 42 from riding up onto a portion of the mold 70, and improves the circumferential positional accuracy of the connecting wall 42 within the mold 70. As a result, similar to the first embodiment, the circumferential positions of the orifice forming members 51 and 52 can be stabilized, and the occurrence of leakage from the orifice 63 due to instability in its position can be suppressed.

[0079] Although the present invention has been described above based on embodiments, it is easy to infer that the present invention is not limited in any way to the above embodiments, and that various improvements and modifications are possible without departing from the spirit of the present invention. For example, the shapes and materials given in each of the above embodiments are just examples, and it is of course possible to use other shapes and materials.

[0080] The inner member 10 may be cylindrical in shape other than a roughly cylindrical shape, or it may be columnar. In the case of a columnar shape, the threaded portion protruding from the axial end of the inner member 10 may be joined to the mating member, or the axial end of the inner member 10 may be integrally molded with the mating member.

[0081] In the above embodiment, a case in which four recesses 39 and 91 are formed has been described, but it is not necessarily limited to this. There should be at least two recesses 39 and 91 in total, one or more on one side of the circumferential direction of the connecting wall 42 and one or more on the other side of the circumferential direction of the connecting wall 42. For example, the two lower recesses 39 of the four recesses 39 in the first embodiment may be omitted. Also, the upper right and lower left recesses 91 of the four recesses 91 in the second embodiment may be omitted. Only the upper right recess 39 of the first embodiment and the upper left recess 91 of the second embodiment may be provided. Four recesses 39 and four recesses 91 may also be provided.

[0082] In the above embodiment, the case in which the recesses 39 and 91 expose the enlarged portion 42a of the connecting wall 42 was described, but the invention is not necessarily limited to this. The recesses 39 and 91 may be arranged to expose the central portion of the connecting wall 42. Alternatively, the enlarged portion 42a of the connecting wall 42 may be omitted, and the circumferential width of the connecting wall 42 may be made uniform along the axial direction.

[0083] In the above embodiment, a stepped portion 77a is provided in the central groove forming portion 77 of the mold 70, and the circumferential edge of the connecting wall 42 is partially exposed from the corner between the groove bottom of the central groove 35 and the circumferential end face 34b. However, the embodiment is not necessarily limited to this. The stepped portion 77a may be omitted, so that the connecting wall 42 is not exposed from the corner between the groove bottom of the central groove 35 and the circumferential end face 34b. [Explanation of Symbols]

[0084] 1.90 Liquid-filled vibration isolation device 10 Inner member 20 Outer member 31 Radial bulkhead 33 First bulkhead (axial bulkhead) 34 Second bulkhead (axial bulkhead) 33a,34a Radial end face 33b,34b Circumferential end face 33d,33e,34d,34e Compressed part 36 Outer groove section 38 Groove 39,91 recess 40 Intermediate tube 41 Peripheral wall 42 Connecting wall 42a Enlarged section 51,51 Orifice forming member 53 Outer perimeter groove 61 1st liquid chamber (liquid chamber) 62 2nd liquid chamber 63 Orifice C axis

Claims

1. An inner member extending along the axis, A cylindrical outer member surrounding the inner member, An intermediate cylinder provided on the inner circumference side of the outer member, The outer circumferential surface of the inner member and the inner circumferential surface of the outer member are connected by elastic bodies that extend around the entire circumference, and a pair of radial partitions are spaced apart from each other in the axial direction, A pair of axial partitions made of elastic material extend radially outward from the outer peripheral surface of the inner member and contact the inner peripheral surface of the outer member, thereby dividing the space surrounded by the inner member, the outer member and the pair of radial partitions in the circumferential direction to form a pair of liquid chambers, A pair of orifice-forming members are arranged in the pair of liquid chambers, with their outer surfaces in contact with the inner surface of the outer member, The orifice is formed by an outer circumferential groove provided on the outer circumferential surface of the orifice-forming member and the inner circumferential surface of the outer member, thereby connecting a pair of liquid chambers. The intermediate cylinder comprises a pair of peripheral walls provided on the outer circumferential surfaces of the pair of radial partition walls, The system comprises a pair of connecting walls that extend radially inward from the circumferential wall, connecting the pair of circumferential walls together, and being embedded in each of the pair of axial partition walls, The pair of axial partition walls each have a portion to be compressed in the circumferential direction between the connecting wall and the orifice forming member, A liquid-filled vibration isolation device characterized in that, in the portion of a pair of axial partition walls other than the portion to be compressed, two or more recesses are formed that expose a portion of the circumferential edges on both sides of the connecting wall over the entire thickness.

2. Of the pair of axial partitions, one is the first partition and the other is the second partition. The orifice passes through the first partition wall without passing through the second partition wall. The liquid-filled vibration isolation device according to claim 1, characterized in that the recess is formed in the second partition wall.

3. The portion to be compressed is provided at least in the second partition wall, The second partition wall is provided on the radial end face of the second partition wall located axially outward from the compressed portion, and has outer grooves extending from the circumferential end face of the second partition wall toward the circumferential center, The connecting wall is provided on the radially opposite side from the outer groove, and comprises a recessed groove that is recessed from the circumferential end face toward the circumferential center, The liquid-filled vibration damping device according to claim 2, characterized in that the recess is formed on the circumferential end face such that the outer groove and the recessed groove communicate in the radial direction.

4. The portion to be compressed is provided at least in the second partition wall, The second partition wall is provided on the radial end face of the second partition wall located axially outward from the compressed portion, and includes outer grooves extending from the circumferential end face of the second partition wall toward the circumferential center. The connecting wall has an enlarged portion whose circumferential dimension gradually widens toward the pair of circumferential walls, The liquid-filled vibration damping device according to claim 2, characterized in that the recess is provided at a position that exposes the circumferential edge of the enlarged portion, and its axial width is smaller than that of the outer groove portion.

5. The liquid-filled vibration damping device according to any one of claims 1 to 4, characterized in that the recesses that expose the circumferential edges of the connecting wall are provided on both sides in the axial direction with respect to the compressed portion, thereby forming a total of four or more recesses.

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