Vibration isolation device

Abstract

In the present application, a first mounting member (11, 111) and a second mounting member (12, 112), an elastic body (13, 113), a partition member (16, 116), and a movable member (41, 141) are included, a restriction passage (24, 124), a plurality of first communication holes (42a, 142a), and a second communication hole (42b, 142b) are formed in the partition member (41, 141), a cylindrical member (21, 121) is provided to a first wall surface (16b, 116b) of the partition member (16, 116), the plurality of first communication holes (42a, 142a) open to both an inner side portion (16f, 116f) and an outer side portion (16g, 116g) in the first wall surface (16b, 116b), and one of the partition member (16) and the cylindrical member (121) forms an elastic force adjusting portion (Z).

Description

TECHNICAL FIELD

[0001] The present application relates to a vibration isolation device that absorbs and attenuates vibrations of a vibration generating portion such as an engine, for example, and is applied to a vehicle, an industrial machine, or the like. This application claims priority based on Japanese Patent Application No. 2019-202574 filed on November 7, 2019, Japanese Patent Application No. 2019-202580 filed on the same day, and Japanese Patent Application No. 2019-202590 filed on the same day, the contents of which are incorporated herein by reference. BACKGROUND

[0002] As such a vibration isolation device, a structure has been known that includes a first mounting member that is cylindrical and is linked to either of a vibration generating portion and a vibration receiving portion, a second mounting member that is linked to the other of the vibration generating portion and the vibration receiving portion, an elastic body that elastically links the two mounting members, a partition member that partitions a liquid chamber in the first mounting member in which a liquid is enclosed into a sub-liquid chamber and a main-liquid chamber that has the elastic body in a portion of a partition wall, and a movable member that is housed in a housing chamber provided in the partition member in a manner capable of being deformed or displaced, a throttle passage that communicates the main-liquid chamber and the sub-liquid chamber is formed in the partition member, a plurality of first communication holes that communicate the main-liquid chamber and the housing chamber, and a second communication hole that communicates the sub-liquid chamber and the housing chamber are formed in the partition member. In this vibration isolation device, when a relatively high frequency idling vibration in a low frequency vibration having a frequency of less than 200 Hz is input in the axial direction, the liquid of the liquid chamber is circulated in the first communication hole and the second communication hole while the movable member is deformed or displaced in the housing chamber, so that the idling vibration is attenuated and absorbed, and when a relatively low frequency rocking vibration is input in the axial direction, the liquid of the liquid chamber is circulated in the throttle passage, so that the rocking vibration is attenuated and absorbed.

[0003] Prior art documents

[0004] Patent documents

[0005] Patent Literature 1: Japanese Patent Application Publication No. 2002-327789 SUMMARY

[0006] PROBLEMS TO BE SOLVED BY THE INVENTION

[0007] However, in the conventional vibration isolation device described above, a medium frequency vibration having a frequency of 200 Hz to 1000 Hz cannot be attenuated and absorbed.

[0008] The present application has been achieved in view of the circumstances described above, and aims to provide a vibration isolation device that can attenuate and absorb a medium frequency vibration.

[0009] MEANS FOR SOLVING THE PROBLEMS

[0010] The vibration isolation device of one aspect of the present application includes: a first mounting member and a second mounting member, the first mounting member being cylindrical, coupled to either of a vibration generating portion and a vibration receiving portion, the second mounting member coupled to the other of the vibration generating portion and the vibration receiving portion; an elastic body elastically coupling the two mounting members; a partition member partitioning a liquid chamber in the first mounting member, in which a liquid is enclosed, into a sub-liquid chamber and a main-liquid chamber having the elastic body in a partial portion of a partition wall, in an axial direction along a central axis of the first mounting member; and a movable member accommodated in an accommodation chamber provided in the partition member in a deformable or displaceable manner, the partition member being formed with a throttle passage communicating the main-liquid chamber and the sub-liquid chamber, a plurality of first communication holes communicating the main-liquid chamber and the accommodation chamber, and a second communication hole communicating the sub-liquid chamber and the accommodation chamber, a first wall surface of the partition member, which is a portion of an inner surface constituting the main-liquid chamber, in which the first communication holes are opened, being provided with a cylindrical member protruding toward the elastic body in the axial direction, the plurality of first communication holes being opened in both an inner side portion, which is on an inner side of the cylindrical member, and an outer side portion, which is on an outer side of the cylindrical member, in the first wall surface, one of the partition member and the cylindrical member forming a spring force adjusting portion that makes a spring force of the elastic body apparently different in a circumferential direction around the central axis.

[0011] Effects of the Invention

[0012] According to the present application, it is possible to attenuate and absorb medium frequency vibrations. BRIEF DESCRIPTION OF DRAWINGS

[0013] Figure 1 is a longitudinal sectional view of a vibration isolation device of a first embodiment of the present application.

[0014] Figure 2 is Figure 1 is a II-II line cross-sectional view of the vibration isolation device shown in FIG. 1.

[0015] Figure 3 is a longitudinal sectional view of a vibration isolation device of a second embodiment of the present application.

[0016] Figure 4 is Figure 3 is a IV-IV line cross-sectional view of the vibration isolation device shown in FIG. 3.

[0017] Figure 5 is a longitudinal sectional view of a vibration isolation device of a third embodiment of the present application.

[0018] Figure 6 is Figure 5 is a A-A line cross-sectional view of the vibration isolation device shown in FIG. 5. DETAILED DESCRIPTION

[0019] (First Embodiment)

[0020] Hereinafter, based on Figure 1 and Figure 2 A first embodiment of a vibration isolation device of the present application will be described.

[0021] As shown in Figure 1 , the vibration isolation device 1 is a liquid-enclosed type vibration isolation device including: a first mounting member 11 that is cylindrical and is linked to either one of a vibration generating portion and a vibration receiving portion, and a second mounting member 12 that is linked to the other one of the vibration generating portion and the vibration receiving portion; an elastic body 13 that elastically links the first mounting member 11 and the second mounting member 12 to each other; a partition member 16 (elastic force adjustment portion Z) that partitions a liquid chamber 19 in the first mounting member 11 in which a liquid is enclosed into a sub-liquid chamber 15 and a main-liquid chamber 14 having the elastic body 13 in a partial portion of a partition wall; and a movable member 41 that is housed in a housing chamber 42 provided in the partition member 16 in a deformable or displaceable manner. The elastic force adjustment portion Z will be described in detail later.

[0022] Hereinafter, a direction along a central axis O of the first mounting member 11 will be referred to as an axial direction. Further, a side on which the second mounting member 12 is located in the axial direction will be referred to as an upper side, and a side on which the partition member 16 is located will be referred to as a lower side. Further, when viewing the vibration isolation device 1 in a plan view from the axial direction, a direction intersecting the central axis O will be referred to as a radial direction, and a direction encircling the central axis O will be referred to as a circumferential direction.

[0023] In addition, the first mounting member 11, the second mounting member 12, and the elastic body 13 each have a circular shape or a circular ring shape and are disposed coaxially with the central axis O when viewed in a plan view.

[0024] In a case where the vibration isolation device 1 is installed in a vehicle, for example, the second mounting member 12 is linked to an engine or the like as the vibration generating portion, and the first mounting member 11 is linked to a vehicle body as the vibration receiving portion. Thus, transmission of vibration of the engine or the like to the vehicle body is suppressed. Alternatively, the first mounting member 11 can be linked to the vibration generating portion, and the second mounting member 12 can be linked to the vibration receiving portion.

[0025] The first mounting member 11 includes an inner cylindrical portion 11a, an outer cylindrical portion 11b, and a lower support portion 11c. The inner cylindrical portion 11a is fitted into the outer cylindrical portion 11b. The lower support portion 11c is formed in a ring shape. An upper surface of an outer peripheral portion of the lower support portion 11c has a lower end opening rim of the outer cylindrical portion 11b placed thereon. The first mounting member 11 is formed as a whole in a cylindrical shape. The first mounting member 11 is linked to the vehicle body or the like as the vibration receiving portion by means of a bracket not shown.

[0026] The second mounting member 12 is located radially inward of the first mounting member 11 and above. The outer diameter of the second mounting member 12 is smaller than the inner diameter of the first mounting member 11. The second mounting member 12 is fitted to the inner side by an unillustrated mounting metal fitting and is joined to an engine or the like as a vibration generating portion by the mounting metal fitting.

[0027] In addition, the relative positions of the first mounting member 11 and the second mounting member 12 are not limited to the illustrated example and can be changed as appropriate. Further, the outer diameter of the second mounting member 12 can be made equal to or greater than the inner diameter of the first mounting member 11.

[0028] The elastic body 13 is formed in a cylindrical shape extending in the axial direction. The elastic body 13 is expanded in diameter as it goes from above to below.

[0029] The first mounting member 11 and the second mounting member 12 are joined to the elastic body 13 respectively at both ends in the axial direction. The second mounting member 12 is joined to the upper end of the elastic body 13, and the first mounting member 11 is joined to the lower end of the elastic body 13. The elastic body 13 closes the upper end opening of the first mounting member 11. The lower end of the elastic body 13 is joined to the inner peripheral surface of the inner cylindrical portion 11a of the first mounting member 11. The upper end of the elastic body 13 is joined to the lower surface of the second mounting member 12. The elastic body 13 is formed of a rubber material or the like and is vulcanization-bonded to the first mounting member 11 and the second mounting member 12. The thickness of the elastic body 13 is made thinner as it goes from above to below. In addition, the elastic body 13 can also be formed of a synthetic resin material or the like, for example.

[0030] A stopper rubber 13a covering the outer peripheral surface and the upper surface of the second mounting member 12 is integrally formed at the upper end of the elastic body 13. A housing 12a surrounding the second mounting member 12 is buried in the elastic body 13 and the stopper rubber 13a.

[0031] The diaphragm 20 is formed of an elastic material such as rubber or soft resin in a bottomed cylindrical shape. The upper end of the diaphragm 20 is sandwiched by the inner peripheral portion of the lower support portion 11c of the first mounting member 11 and the outer peripheral portion of the partition member 16, whereby the liquid tightness of the inside of the diaphragm 20 is ensured, and the lower end opening of the first mounting member 11 is closed.

[0032] In addition, in the illustrated example, the bottom of the diaphragm 20 is shaped so as to be deeper on the outer peripheral side and shallower in the central portion. However, as the shape of the diaphragm 20, various shapes known in the art can be employed in addition to such a shape.

[0033] The lower end opening portion of the first mounting member 11 is closed by the diaphragm 20, and the upper end opening portion of the first mounting member 11 is closed by the elastic body 13 as described above, so that the first mounting member 11 becomes a liquid chamber 19 that is liquid-tightly sealed. A liquid is enclosed (filled) in the liquid chamber 19. As the liquid, for example, ethylene glycol, water, or silicone oil, and the like can be cited.

[0034] The liquid chamber 19 is divided into the main liquid chamber 14 and the sub-liquid chamber 15 in the axial direction by the partition member 16. The main liquid chamber 14 has the inner peripheral surface 13c of the elastic body 13 in part of the wall surface, and is a space surrounded by the elastic body 13 and the partition member 16, and the internal volume changes according to the deformation of the elastic body 13. The sub-liquid chamber 15 is a space surrounded by the diaphragm 20 and the partition member 16, and the internal volume changes according to the deformation of the diaphragm 20. The vibration isolation device 1 including such a structure is a compression type device that is used in a manner that the main liquid chamber 14 is located on the upper side in the vertical direction and the sub-liquid chamber 15 is located on the lower side in the vertical direction.

[0035] The partition member 16 is formed with a plurality of first communication holes 42a that communicate the main liquid chamber 14 and the accommodation chamber 42 and a second communication hole 42b that communicates the sub-liquid chamber 15 and the accommodation chamber 42. The partition member 16 is formed with a plurality of second communication holes 42b, and the number of each of the first communication holes 42a and the second communication holes 42b is the same as each other. Each of the first communication holes 42a and the second communication holes 42b oppose each other in the axial direction. The inner diameter (flow path cross-sectional area) of each of the first communication holes 42a and the second communication holes 42b that oppose each other in the axial direction is the same as each other. The flow path length of each of the first communication holes 42a and the second communication holes 42b that oppose each other in the axial direction is the same as each other. In addition, one second communication hole 42b can be formed in the partition member 16.

[0036] Here, in the partition member 16, the upper wall surface that constitutes part of the inner surface of the main liquid chamber 14 and the lower wall surface that constitutes part of the inner surface of the sub-liquid chamber 15 each have a circular shape that is coaxially arranged with the center axis O when viewed from the axial direction. The diameters of the upper wall surface and the lower wall surface of the partition member 16 are equal to each other. The upper wall surface of the partition member 16 opposes the inner peripheral surface 13c of the elastic body 13 in the axial direction, and the lower wall surface of the partition member 16 opposes the inner surface of the diaphragm 20 in the axial direction.

[0037] In the illustrated example, a recess is formed on the entire area of ​​the upper wall of the partition member 16, excluding the peripheral portion 16a. A plurality of first connecting holes 42a open across the entire area of ​​the bottom surface (hereinafter referred to as the first wall surface) 16b of this recess. A recess is formed on the entire area of ​​the lower wall of the partition member 16, excluding the peripheral portion 16c. A plurality of second connecting holes 42b open across the entire area of ​​the bottom surface (hereinafter referred to as the second wall surface) 16d of this recess. The recesses on both the upper and lower walls are circular in shape, coaxially arranged with the central axis O when viewed from the axial direction, and the inner diameter and depth of each recess are equal to each other.

[0038] The storage chamber 42 is formed in the axial portion of the partition member 16 between the first wall surface 16b and the second wall surface 16d. When viewed axially, the storage chamber 42 is circular in shape and coaxially aligned with the central axis O. The diameter of the storage chamber 42 is larger than the diameters of both the first wall surface 16b and the second wall surface 16d.

[0039] The movable member 41 is formed as a plate with its front and back surfaces facing axially. When viewed from the axial direction, the movable member 41 is circular in shape and is coaxially arranged with the central axis O. The movable member 41 is formed, for example, from an elastic material such as rubber or soft resin.

[0040] A throttling flow path 24 is formed in the partition member 16, connecting the main liquid chamber 14 and the auxiliary liquid chamber 15. The throttling flow path 24 is formed in the axial portion of the partition member 16 between the outer peripheral edge 16a of the upper wall and the outer peripheral edge 16c of the lower wall. The upper end of the throttling flow path 24 is located above the first wall surface 16b, and the lower end is located below the second wall surface 16d. The cross-sectional shape of the throttling flow path 24 is a rectangular shape that is longer in the axial direction. The resonant frequency of the throttling flow path 24 is lower than the resonant frequencies of the first connecting hole 42a and the second connecting hole 42b.

[0041] like Figure 2 As shown, the opening 25 on the main liquid chamber 14 side of the throttling passage 24 is formed on the outer peripheral edge 16a of the upper wall of the partition member 16. This opening 25 is configured by multiple rows of holes 25b arranged circumferentially at intervals through through holes 25a, with different radial and circumferential positions. The inner diameter of the through hole 25a is smaller than the inner diameter of the first connecting hole 42a. Two rows of holes 25b are arranged on the outer peripheral edge 16a of the upper wall of the partition member 16. The circumferential offset and radial offset of each row of holes 25b are equal to the inner diameter of the through hole 25a.

[0042] The opening portion on the sub liquid chamber 15 side of the throttle passage 24 is formed at the outer peripheral edge portion 16c of the lower wall surface of the partition member 16, and is one opening having a larger opening area than the sum of the opening areas of the plurality of through holes 25a, that is, the opening area of the opening portion 25 on the main liquid chamber 14 side. The opening portion 25 on the main liquid chamber 14 side and the opening portion on the sub liquid chamber 15 side of the throttle passage 24 are located at positions that are radially outward of the first communication hole 42a and the second communication hole 42b.

[0043] A flange portion 16e is formed at the upper end portion of the partition member 16, protrudes toward the radially outer side, and continuously extends in the entire circumferential range. The upper surface of the flange portion 16e abuts against the lower end opening edge of each of the inner cylinder portion 11a and the outer cylinder portion 11b of the first mounting member 11 via the annular upper sealing material 27. The lower surface of the flange portion 16e abuts against the upper surface of the inner circumferential portion of the lower support portion 11c of the first mounting member 11 via the upper end opening edge of the diaphragm 20 and the annular lower sealing material 28 that surrounds the upper end opening edge of the diaphragm 20 from the radially outer side.

[0044] The partition member 16 includes an upper cylinder 31 and a lower cylinder 32 that are arranged in abutment with each other in the axial direction, an upper wall 33 that closes the lower end opening portion of the upper cylinder 31, and a lower wall 34 that closes the upper end opening portion of the lower cylinder 32. In addition, the partition member 16 can also be integrally formed.

[0045] The upper end opening edge of the upper cylinder 31 is the outer peripheral edge portion 16a of the upper wall surface of the aforementioned partition member 16. A flange portion 16e is formed at the upper end portion of the upper cylinder 31. A circumferential groove is formed at a portion of the lower end opening edge of the upper cylinder 31 that is located radially outward of the inner circumferential portion, the circumferential groove being recessed toward the upper side and being open toward the radially outer side.

[0046] The upper wall 33 is fixed to the inner circumferential portion of the lower end opening edge of the upper cylinder 31. The first communication hole 42a is formed at the upper wall 33.

[0047] A circumferential groove recessed toward the lower side is formed at a radially intermediate portion of the upper end opening edge of the lower cylinder 32 that is axially opposite to the circumferential groove of the upper cylinder 31. The throttle passage 24 is formed by the circumferential groove and the circumferential groove of the upper cylinder 31. The outer peripheral edge portion of the upper end opening edge of the lower cylinder 32 that is located radially outward of the circumferential groove abuts against the lower surface of the flange portion 16e of the upper cylinder 31. The upper end portion of the diaphragm 20 is fitted into the upper end portion of the lower cylinder 32, and the upper end portion of the diaphragm 20 is fitted into the lower support portion 11c of the first mounting member 11. Thus, the upper end portion of the diaphragm 20 is clamped in the radial direction by the outer circumferential surface of the lower cylinder 32 and the inner circumferential surface of the lower support portion 11c.

[0048] The lower wall 34 is fixed to the inner circumferential portion of the upper end opening edge of the lower cylinder 32. The second communication hole 42b is formed at the lower wall 34.

[0049] At least one of the inner circumferential portion of the lower end opening edge of the upper cylinder 31 and the inner circumferential portion of the upper end opening edge of the lower cylinder 32 is formed with an abutting protrusion 34a, 34b that protrudes toward the other and abuts against the other. In the example illustrated, the abutting protrusions 34a, 34b are formed at both the inner circumferential portion of the lower end opening edge of the upper cylinder 31 and the inner circumferential portion of the upper end opening edge of the lower cylinder 32. The abutting protrusions 34a, 34b are formed in a ring shape disposed coaxially with the center axis O, and the upper wall 33 and the lower wall 34 are disposed on the radially inner side of the abutting protrusions 34a, 34b in a state of being spaced apart from each other by a gap in the axial direction. The accommodation chamber 42 is formed by the lower surface of the upper wall 33, the upper surface of the lower wall 34, and the inner circumferential surface of the abutting protrusions 34a, 34b.

[0050] Further, in the present embodiment, the first wall surface 16b of the partition member 16, which is provided with the first communication hole 42a and constitutes a part of the inner surface of the main liquid chamber 14, is provided with the cylindrical member 21 that protrudes in the axial direction toward the elastic body 13.

[0051] The cylindrical member 21 is formed in a cylindrical shape and is disposed coaxially with the center axis O. The cylindrical member 21 extends straight in the axial direction. The length of the cylindrical member 21 in the axial direction is 20% or more of the maximum height T in the axial direction of the main liquid chamber 14. In the example illustrated, the maximum height T in the axial direction of the main liquid chamber 14 is the distance in the axial direction between the upper end portion of the inner circumferential surface 13c of the elastic body 13, which extends toward the radially inner side as it goes from the lower side toward the upper side, and the first wall surface 16b. The length of the cylindrical member 21 in the axial direction is set so that the upper end portion of the cylindrical member 21 does not abut against the inner circumferential surface 13c of the elastic body 13 when a static load in the axial direction is applied to the vibration isolation device 1 and when vibration in the axial direction is input.

[0052] Further, as described above, the inner circumferential surface 13c of the elastic body 13 is a portion that extends toward the radially inner side as it goes from the lower side toward the upper side, and in the case where the upper end portion of the inner surface of the elastic body 13, which divides the main liquid chamber 14, is provided with a recessed portion that is recessed toward the upper side as in the example illustrated, the upper end portion of the inner circumferential surface 13c of the elastic body 13 refers to the opening circumferential portion of the recessed portion of the inner surface of the elastic body 13.

[0053] The upper portion of the cylindrical member 21 protrudes upward from the upper end opening of the recessed portion formed in the upper wall surface of the partition member 16. The outer peripheral surface of the upper portion of the cylindrical member 21 opposes the lower end portion of the inner peripheral surface of the inner cylindrical portion 11a of the first mounting member 11 and the lower end portion of the inner peripheral surface 13c of the elastic body 13 in the radial direction. The protruding length of the upper portion of the cylindrical member 21 from the upper end opening of the recessed portion is shorter than the depth of the recessed portion. Further, the protruding length is shorter than the axial distance between the portion of the inner peripheral surface 13c of the elastic body 13 that opposes the upper end opening edge of the cylindrical member 21 in the axial direction and the upper end opening edge of the cylindrical member 21. The upper end opening edge of the cylindrical member 21 opposes the portion of the inner peripheral surface 13c of the elastic body 13 that extends toward the inside in the radial direction as it extends upward from below, which is offset downward from the central portion in the direction that extends from the inner peripheral surface 13c in the axial direction in a longitudinal cross section.

[0054] The radius of the inner peripheral surface of the cylindrical member 21 is larger than the radial distance between the outer peripheral surface of the cylindrical member 21 and the inner peripheral surface of the recessed portion formed in the upper wall surface of the partition member 16. The inner diameter of the cylindrical member 21 is more than half the maximum inner diameter R of the main liquid chamber 14. In the illustrated example, the maximum inner diameter R of the main liquid chamber 14 is the inner diameter of the lower end portion of the inner cylindrical portion 11a of the first mounting member 11. The planar area of the portion of the first wall surface 16b that is located inside the cylindrical member 21 (hereinafter referred to as the inside portion) 16f is larger than the planar area of the portion that is located outside the cylindrical member 21 (hereinafter referred to as the outside portion) 16g.

[0055] The plurality of first communication holes 42a are opened in both the inside portion 16f and the outside portion 16g of the first wall surface 16b. The plurality of first communication holes 42a all oppose the upper surface of the movable member 41.

[0056] The cylindrical member 21 is attached to the portion of the first wall surface 16b that is located between adjacent first communication holes 42a, and is disposed so as not to overlap the first communication holes 42a. The cylindrical member 21 is disposed so that the inner peripheral surface and the outer peripheral surface thereof contact the first communication holes 42a when viewed in the axial direction.

[0057] It is also possible that one of the partition member 16 and the cylindrical member 21 forms a spring force adjustment portion Z that makes the spring force (elasticity) of the elastic body 13 appear to be different in the circumferential direction around the center axis O of the first mounting member 11. In the present embodiment, the partition member 16 that forms the spring force adjustment portion Z will be described.

[0058] In the present embodiment, the plurality of first communication holes 42a are provided in each of the circumferential first region X and the circumferential second region Y that are different in position from the first region X in the first wall surface 16b.

[0059] Further, in the present embodiment, the flow resistance of the liquid flowing through the first communication holes 42a in the first region X, which opens in the circumferential direction, is different from the flow resistance of the liquid flowing through the first communication holes 42a in the second region Y, which opens in the circumferential direction.

[0060] The first region X and the second region Y are provided so as to differ in position in the circumferential direction, respectively. The first region X and the second region Y each include a portion of the inner side portion 16f and the outer side portion 16g, respectively. The plurality of first communication holes 42a each open in the first region X and the second region Y. Each of the circumferential direction and the radial direction of the first region X is larger than the flow path cross-sectional area of the first communication hole 42a that opens in the first region X. Each of the circumferential direction and the radial direction of the second region Y is larger than the flow path cross-sectional area of the first communication hole 42a that opens in the second region Y.

[0061] The proportion of the opening area of the first communication hole 42a in the planar area of the first region X is different from the proportion of the opening area of the first communication hole 42a in the planar area of the second region Y. In the illustrated example, the proportion of the opening area of the first communication hole 42a in the planar area of the first region X is larger than the proportion of the opening area of the first communication hole 42a in the planar area of the second region Y.

[0062] The total of the opening areas of the first communication holes 42a that open in the first region X is larger than the total of the opening areas of the first communication holes 42a that open in the second region Y.

[0063] The first communication holes 42a that open in the first region X are arranged in multiple numbers at equal intervals B, C in the range of the entire region of the first region X. In the first region X, the intervals B, C between the first communication holes 42a adjacent to each other are narrower than the inner diameter of these first communication holes 42a. The first communication holes 42a that open in the second region Y are arranged in multiple numbers at equal intervals D, E in the range of the entire region of the second region Y. In the second region Y, the intervals D, E between the first communication holes 42a adjacent to each other are wider than the inner diameter of these first communication holes 42a.

[0064] The intervals B, C between the first communication holes 42a adjacent to each other in the first region X are different from the intervals D, E between the first communication holes 42a adjacent to each other in the second region Y. In the illustrated example, the intervals B, C between the first communication holes 42a adjacent to each other in the first region X are narrower than the intervals D, E between the first communication holes 42a adjacent to each other in the second region Y.

[0065] Further, the intervals B, C between the first communication holes 42a adjacent to each other in the first region X can be set to the intervals D, E between the first communication holes 42a adjacent to each other in the second region Y or more.

[0066] In the illustrated example, in the first region X and the second region Y, the first communication holes 42a are respectively arranged in multiple numbers at equal intervals B, D in the circumferential direction, and the rows of the first communication holes 42a arranged in the circumferential direction are arranged in multiple numbers in a concentric circle shape centered on the center axis O at equal intervals C, E in the radial direction. In the first region X, the interval B in the circumferential direction and the interval C in the radial direction are the same as each other. In the second region Y, the interval D in the circumferential direction and the interval E in the radial direction are the same as each other.

[0067] Further, in the first region X, the interval B in the circumferential direction and the interval C in the radial direction can be different from each other. In the second region Y, the interval D in the circumferential direction and the interval E in the radial direction can be different from each other.

[0068] The flow path cross-sectional area of the first communication hole 42a opening in the first region X and the flow path cross-sectional area of the first communication hole 42a opening in the second region Y are different from each other. The flow path cross-sectional area of each first communication hole 42a is the same in the range of the entire length in the axial direction.

[0069] Further, the flow path cross-sectional area of each first communication hole 42a can be different depending on the position in the axial direction. In this case, the flow path cross-sectional area of the first communication hole 42a can be expressed by the average value of the flow path cross-sectional areas at multiple positions along the axial direction.

[0070] In the present embodiment, the flow path cross-sectional area of the first communication hole 42a opening in the first region X is larger than the flow path cross-sectional area of the first communication hole 42a opening in the second region Y. Due to this, the flow resistance of the liquid flowing in the first communication hole 42a opening in the second region Y is higher than the flow resistance of the liquid flowing in the first communication hole 42a opening in the first region X. In the first region X, the flow resistances of the liquids flowing in the multiple first communication holes 42a are the same as each other. In the second region Y, the flow resistances of the liquids flowing in the multiple first communication holes 42a are the same as each other.

[0071] Here, the thicknesses of the upper wall 33 and the lower wall 34 are the same in the range of the entire region, and the flow path length of the first communication hole 42a opening in the first region X and the flow path length of the first communication hole 42a opening in the second region Y are the same as each other.

[0072] When viewed in the axial direction, the first region X is respectively provided at positions facing each other in one direction across the center axis O, and the second region Y is respectively provided at positions facing each other in another direction orthogonal to the one direction across the center axis O.

[0073] The first region X and the second region Y are provided in the entire region of the first wall surface 16b. The circumferential size of each of the first region X and the second region Y is the same as each other. The planar area of each of the first region X and the second region Y is the same as each other. Each of the first region X and the second region Y is provided in the first wall surface 16b in an angle range of about 90° centered on the center axis O. The first region X and the second region Y are alternately provided along the circumferential direction. The first region X and the second region Y have a fan shape when viewed in the axial direction. In addition, the first region X and the second region Y can also have a quadrangular shape or the like when viewed in the axial direction, for example.

[0074] In the vibration isolation device 1 including such a structure, when the idling vibration, which is higher in frequency, among the low-frequency vibrations is input in the axial direction, the movable member 41 deforms or displaces within the accommodation chamber 42 while the liquid of the liquid chamber 19 flows through the first communication hole 42a and the second communication hole 42b, thereby attenuating and absorbing the vibration. In addition, when the sway vibration, which is lower in frequency, among the low-frequency vibrations is input in the axial direction, the liquid of the liquid chamber 19 flows through the throttle passage 24, thereby attenuating and absorbing the vibration.

[0075] As described above, according to the vibration isolation device 1 of the present embodiment, since the tubular member 21 protruding toward the elastic body 13 is provided in the first wall surface 16b of the partition member 16, when the medium-frequency vibration in the axial direction is input, the portion of the elastic body 13 located on the first mounting member 11 side of the node portion, which is generated in the central portion of the elastic body 13 in the related art, for example, is displaced to the second mounting member 12 side due to the liquid being difficult to flow between the inner peripheral surface of the main liquid chamber 14 and the outer peripheral surface of the upper portion of the tubular member 21, and the portion of the elastic body 13 located on the first mounting member 11 side of the node portion is more easily deformed than the portion of the elastic body 13 located on the second mounting member 12 side of the node portion. Thus, when the medium-frequency vibration in the axial direction is input, the portion of the elastic body 13 located on the first mounting member 11 side of the node portion is actively deformed, the rigidity of the elastic body 13 can be apparently reduced, and the vibration can be attenuated and absorbed.

[0076] In addition, since the plurality of first communication holes 42a are opened to both the inner side portion 16f and the outer side portion 16g of the first wall surface 16b, a large number of first communication holes 42a can be arranged in the first wall surface 16b, and the idling vibration, which is higher in frequency, among the low-frequency vibrations, for example, can be reliably attenuated and absorbed.

[0077] Further, since the flow resistance of the liquid flowing through the first communication holes 42a in the first region X which opens in the circumferential direction is different from the flow resistance of the liquid flowing through the first communication holes 42a in the second region Y which opens in the circumferential direction in the first wall surface 16b, the first communication holes 42a in which the liquid flows more are changed when vibration in the lateral direction which crosses the axial direction and which is in the direction of the first region X with respect to the center axis O is inputted and when vibration in the lateral direction which crosses the axial direction and which is in the direction of the second region Y with respect to the center axis O is inputted, so that the degree of the flow of the liquid of the liquid chamber 19 as a whole can be made different. Thus, the elastic force exhibited by the vibration isolation device 1 when vibration in the lateral direction which is in the direction of the first region X with respect to the center axis O is inputted and when vibration in the lateral direction which is in the direction of the second region Y with respect to the center axis O is inputted can be made different. That is, the cylindrical member 21 which forms the elastic force adjusting portion Z can make the rigidity of the elastic body 13 apparently different in the circumferential direction around the center axis O of the first mounting member 11, that is, can make the elastic force of the elastic body 13 apparently different. Thus, for example, even in the case where the elastic force of the elastic body 13 and the position of the notch portion are different in the front-rear direction and the left-right direction in the radial direction, tuning and the like can be easily performed.

[0078] Further, the thickness or the length of the elastic body 13 can be made different in the front-rear direction and the left-right direction, for example, so that the elastic force of the elastic body 13 is made different.

[0079] In the illustrated example, since the flow resistance of the first region X is lower than the flow resistance of the second region Y, the elastic force exhibited by the vibration isolation device 1 when vibration in the lateral direction which is in the direction of the first region X with respect to the center axis O is inputted is lower than the elastic force exhibited by the vibration isolation device 1 when vibration in the lateral direction which is in the direction of the second region Y with respect to the center axis O is inputted.

[0080] Further, the elastic force exhibited by the vibration isolation device 1 when vibration in the lateral direction which is in the direction of the first region X with respect to the center axis O is inputted and when vibration in the lateral direction which is in the direction of the second region Y with respect to the center axis O is inputted can be made different by designing the first communication holes 42a formed in the first wall surface 16b instead of the cylindrical member 21 which protrudes from the first wall surface 16b, so that the design is not easily restricted as compared with the case where the cylindrical member 21 is designed to have such an effect.

[0081] Since the flow path cross-sectional area of the first communication hole 42a opening in the first region X and the flow path cross-sectional area of the first communication hole 42a opening in the second region Y are different from each other, it is possible to reliably make the flow resistance of the liquid flowing in the former first communication hole 42a and the flow resistance of the liquid flowing in the latter first communication hole 42a different from each other.

[0082] Since the flow path cross-sectional area of the first communication hole 42a opening in the first region X and the flow path cross-sectional area of the first communication hole 42a opening in the second region Y are different from each other, it is possible to reliably make the proportion of the opening area of the first communication hole 42a in the planar area of the first region X and the proportion of the opening area of the first communication hole 42a in the planar area of the second region Y different from each other.

[0083] Since the proportion of the opening area of the first communication hole 42a in the planar area of the first region X and the proportion of the opening area of the first communication hole 42a in the planar area of the second region Y are different from each other, when vibration in the lateral direction in which the first region X is located with respect to the center axis O is input and when vibration in the lateral direction in which the second region Y is located with respect to the center axis O is input, the first communication hole 42a in which the liquid flows more in the plurality of first communication holes 42a changes, and thus it is possible to make the degree of flow of the liquid of the entire liquid chamber 19 different.

[0084] Thus, it is possible to make the elastic force exhibited by the vibration isolation device 1 different when vibration in the lateral direction in which the first region X is located with respect to the center axis O is input and when vibration in the lateral direction in which the second region Y is located with respect to the center axis O is input. Thus, for example, even in the case where the elastic force of the elastic body 13 and the position of the said section are different in the front-rear direction and the left-right direction in the radial direction, it is possible to easily perform tuning and the like.

[0085] In addition, it can also be that the thickness or the length of the elastic body 13 is made different in the front-rear direction and the left-right direction, for example, and thus the elastic force of the elastic body 13 is made different.

[0086] In the illustrated example, since the said proportion of the first region X is larger than the said proportion of the second region Y, the elastic force exhibited by the vibration isolation device 1 when vibration in the lateral direction in which the first region X is located with respect to the center axis O is input is lower than the elastic force exhibited by the vibration isolation device 1 when vibration in the lateral direction in which the second region Y is located with respect to the center axis O is input.

[0087] When viewed from the axial direction, the first region X is located opposite each other in one direction, separated by the central axis O, and the second region Y is located opposite each other in another direction orthogonal to the first direction, separated by the central axis O. Therefore, the vibration isolation device 1 can reliably exhibit different elasticity when vibration in the lateral direction relative to the central axis O is applied to the direction of the first region X relative to the central axis O, and when vibration in the lateral direction relative to the central axis O is applied to the direction of the second region Y relative to the central axis O.

[0088] Since the intervals B and C between adjacent first connecting holes 42a in region X and the intervals D and E between adjacent first connecting holes 42a in region Y are different, it is possible to reliably ensure that the proportion of the opening area of ​​the first connecting hole 42a in the planar area of ​​region X is different from the proportion of the opening area of ​​the first connecting hole 42a in the planar area of ​​region Y.

[0089] Furthermore, since the axial length of the cylindrical member 21 is more than 20% of the maximum axial height T of the main liquid chamber 14, it can reliably attenuate and absorb axial mid-frequency vibrations.

[0090] Furthermore, since the inner diameter of the cylindrical member 21 is more than half of the maximum inner diameter R of the main liquid chamber 14, it can reliably attenuate and absorb axial mid-frequency vibrations.

[0091] (Second Implementation)

[0092] Next, the second embodiment of the present invention will be described, the basic structure of which is the same as that of the first embodiment. Therefore, the same reference numerals are used to refer to the same structures, and their descriptions are omitted; only the differences are described.

[0093] In this embodiment, the partition member 16 that forms the elasticity adjustment part Z will also be described.

[0094] In the vibration isolation device 2 of this embodiment, such as Figure 3 As shown, the flow path length of the first connecting hole 42a opening in the first region X is different from the flow path length of the first connecting hole 42a opening in the second region Y. Therefore, the flow resistance of the liquid flowing through the first connecting hole 42a opening in the first region X is different from the flow resistance of the liquid flowing through the first connecting hole 42a opening in the second region Y.

[0095] In this embodiment, the flow path length of the first connecting hole 42a opening in the second region Y is longer than the flow path length of the first connecting hole 42a opening in the first region X. Therefore, the flow resistance of the liquid flowing through the first connecting hole 42a opening in the second region Y is higher than the flow resistance of the liquid flowing through the first connecting hole 42a opening in the first region X.

[0096] In the illustrated example, the upper wall 33 and the lower wall 34 are thicker in the circumferential direction of the second region Y than in the circumferential direction of the first region X. Therefore, the flow path length of the first connecting hole 42a opening in the second region Y is longer than the flow path length of the first connecting hole 42a opening in the first region X.

[0097] The lower surface of the upper wall 33 and the upper surface of the lower wall 34 are flat throughout the entire region. The thickness of the circumferential portion of the upper wall 33 and the lower wall 34, respectively, in the second region Y, is the same as that of the lower wall 33 and the lower wall 34. The thickness of the circumferential portion of the upper wall 33 and the lower wall 34, respectively, in the first region X, is the same as that of the upper wall 33 and the lower wall 34.

[0098] In the first wall surface 16b, the second region Y is located above the first region X. The portion of the lower opening edge of the cylindrical member 21 located in the first region X is located below the portion of the lower opening edge of the cylindrical member 21 located in the second region Y. The lower opening edge of the cylindrical member 21 abuts against the first wall surface 16b over its entire circumferential length.

[0099] like Figure 4 As shown, the flow path cross-sectional area of ​​the first connecting hole 42a opening in the first region X is the same as that of the first connecting hole 42a opening in the second region Y.

[0100] All of the first connecting holes 42a opening on the first wall surface 16b are adjacent to each other and the spacing between them is equal.

[0101] The proportion of the opening area of ​​the first connecting hole 42a in the planar area of ​​the first region X is the same as the proportion of the opening area of ​​the first connecting hole 42a in the planar area of ​​the second region Y. The sum of the opening areas of the first connecting holes 42a opening in the first region X is the same as the sum of the opening areas of the first connecting holes 42a opening in the second region Y.

[0102] According to the vibration isolation device 2 of the present embodiment, since the flow path length of the first communication hole 42a opening in the first region X and the flow path length of the first communication hole 42a opening in the second region Y are different from each other, the flow resistance of the liquid flowing in the former first communication hole 42a and the flow resistance of the liquid flowing in the latter first communication hole 42a can be reliably made different from each other, and the vibration isolation device 2 has the same effect as the vibration isolation device 1 of the first embodiment.

[0103] A vibration isolation device according to one aspect of the present invention includes: a first mounting member and a second mounting member, the first mounting member being cylindrical, and being coupled to either one of a vibration generating portion and a vibration receiving portion, the second mounting member being coupled to the other one of the vibration generating portion and the vibration receiving portion; an elastic body elastically coupling the two mounting members; a partition member partitioning a liquid chamber in the first mounting member in which a liquid is enclosed into a sub-liquid chamber and a main-liquid chamber having the elastic body in a partial portion of a partition wall in an axial direction along a center axis of the first mounting member; and a movable member accommodated in an accommodation chamber provided in the partition member in a deformable or displaceable manner, the partition member being provided with a throttle passage communicating the main-liquid chamber and the sub-liquid chamber, a plurality of first communication holes communicating the main-liquid chamber and the accommodation chamber, and a second communication hole communicating the sub-liquid chamber and the accommodation chamber, a first wall surface of the partition member, which is provided with the first communication hole and constitutes a portion of an inner surface of the main-liquid chamber, being provided with a cylindrical member protruding toward the elastic body in the axial direction, the plurality of first communication holes being opened in both an inner side portion inside the cylindrical member and an outer side portion outside the cylindrical member in the first wall surface, one of the partition member and the cylindrical member forming a spring force adjusting portion that makes the spring force of the elastic body apparently different in a circumferential direction around the center axis.

[0104] A vibration isolation device according to one aspect of the present invention, since the cylindrical member protruding toward the elastic body is provided in the first wall surface of the partition member, with input of a mid-frequency vibration in the axial direction, when the elastic body is deformed in a secondary vibration mode in a longitudinal cross section along the axial direction, a node portion that is conventionally generated in a central portion of the elastic body is shifted to the second mounting member side, for example, due to difficulty of flow of the liquid between an inner peripheral surface of the main-liquid chamber and an outer peripheral surface of the cylindrical member, and a portion of the elastic body located on the first mounting member side than the node portion is easily deformed compared to a portion of the elastic body located on the second mounting member side than the node portion. Thereby, with input of the mid-frequency vibration in the axial direction, the portion of the elastic body located on the first mounting member side than the node portion is actively deformed, the rigidity of the elastic body can be apparently reduced, and the vibration can be attenuated and absorbed.

[0105] Further, since the plurality of first communication holes are opened in both the inner side portion on the inner side of the tubular member and the outer side portion on the outer side of the tubular member in the first wall surface, it is possible to arrange a large number of the first communication holes in the first wall surface, for example, to reliably attenuate and absorb an idling vibration and the like which is a higher frequency in low frequency vibrations.

[0106] Further, since one of the partition member and the tubular member forms an elastic force adjusting portion which makes the elastic force of the elastic body apparently different in the circumferential direction around the center axis, it is possible to make the elastic force of the elastic body apparently different in the circumferential direction around the center axis.

[0107] In the partition member which forms the elastic force adjusting portion, it is also possible that the flow resistance of the liquid flowing in the first communication hole opened in the first region of the circumferential direction around the center axis in the first wall surface is different from the flow resistance of the liquid flowing in the first communication hole opened in the second region of the circumferential direction.

[0108] In this case, in the partition member which forms the elastic force adjusting portion, since the flow resistance of the liquid flowing in the first communication hole opened in the first region of the circumferential direction in the first wall surface is different from the flow resistance of the liquid flowing in the first communication hole opened in the second region of the circumferential direction, when a vibration in a direction in which the first region is located with respect to the center axis in a transverse direction intersecting the axial direction is input and when a vibration in a direction in which the second region is located with respect to the center axis in the transverse direction intersecting the axial direction is input, the first communication hole in which the liquid flows more in the plurality of first communication holes changes, and thus it is possible to make the degree of flow of the liquid in the entire liquid chamber different. Thereby, it is possible to make the elastic force exhibited by the vibration isolation device different when a vibration in a direction in which the first region is located with respect to the center axis in the transverse direction is input and when a vibration in a direction in which the second region is located with respect to the center axis in the transverse direction is input. Thus, for example, even in a case where the elastic force of the elastic body and the position of the joint portion are different in the front-rear direction and the left-right direction in the radial direction, it is possible to easily perform tuning and the like.

[0109] Further, it is possible to make the elastic force exhibited by the vibration isolation device different when a vibration in a direction in which the first region is located with respect to the center axis in the transverse direction is input and when a vibration in a direction in which the second region is located with respect to the center axis in the transverse direction is input by designing the first communication hole formed in the first wall surface rather than the tubular member which protrudes from the first wall surface, and thus it is less likely to cause a design constraint compared to a case where the tubular member is designed to have such an effect.

[0110] The flow path cross-sectional area of the first communication hole opening in the first region and the flow path cross-sectional area of the first communication hole opening in the second region can be different from each other.

[0111] In this case, since the flow path cross-sectional area of the first communication hole opening in the first region and the flow path cross-sectional area of the first communication hole opening in the second region are different from each other, the flow resistance of the liquid flowing in the former first communication hole and the flow resistance of the liquid flowing in the latter first communication hole can be reliably made different from each other.

[0112] The flow path length of the first communication hole opening in the first region and the flow path length of the first communication hole opening in the second region can be different from each other.

[0113] In this case, since the flow path length of the first communication hole opening in the first region and the flow path length of the first communication hole opening in the second region are different from each other, the flow resistance of the liquid flowing in the former first communication hole and the flow resistance of the liquid flowing in the latter first communication hole can be reliably made different from each other.

[0114] The proportion of the opening area of the first communication hole in the planar area of the first region and the proportion of the opening area of the first communication hole in the planar area of the second region can be different from each other.

[0115] In this case, since the proportion of the opening area of the first communication hole in the planar area of the first region and the proportion of the opening area of the first communication hole in the planar area of the second region are different from each other, when vibration in the lateral direction in the direction of the first region with respect to the center axis is input and when vibration in the lateral direction in the direction of the second region with respect to the center axis is input, the first communication hole in which the liquid flows more in the plurality of first communication holes changes, and thus the degree of flow of the liquid in the entire liquid chamber can be made different.

[0116] The first regions can be respectively provided at positions facing each other in one direction across the center axis, and the second regions can be respectively provided at positions facing each other in another direction orthogonal to the one direction across the center axis, when viewed in the axial direction.

[0117] In this case, the first regions are respectively provided at positions opposite each other in one direction across the center axis, and the second regions are respectively provided at positions opposite each other in another direction orthogonal to the one direction across the center axis, when viewed in the axial direction. Thus, it is possible to reliably make the elastic force exhibited by the vibration isolation device different when a vibration in a lateral direction with respect to the direction in which the first regions are located with respect to the center axis is input and when a vibration in the lateral direction with respect to the direction in which the second regions are located with respect to the center axis is input.

[0118] In the partition member forming the elastic force adjustment portion, the first regions in the first wall surface around the circumferential direction of the center axis and the second regions provided at positions different from the first regions around the circumferential direction each have a plurality of the first communication holes, and the proportion of the opening area of the first communication holes in the planar area of the first regions and the proportion of the opening area of the first communication holes in the planar area of the second regions are different from each other.

[0119] In this case, in the partition member forming the elastic force adjustment portion, because the proportion of the opening area of the first communication holes in the planar area of the first regions and the proportion of the opening area of the first communication holes in the planar area of the second regions are different from each other in the first wall surface, the first communication holes in which the liquid flows more are changed among the plurality of first communication holes when a vibration in a lateral direction crossing the axial direction with respect to the direction in which the first regions are located with respect to the center axis is input and when a vibration in the lateral direction crossing the axial direction with respect to the direction in which the second regions are located with respect to the center axis is input, and thus it is possible to make the degree of flow of the liquid in the entire liquid chamber different. Thus, it is possible to make the elastic force exhibited by the vibration isolation device different when a vibration in a lateral direction with respect to the direction in which the first regions are located with respect to the center axis is input and when a vibration in the lateral direction with respect to the direction in which the second regions are located with respect to the center axis is input. Thus, for example, even in a case where the elastic force of the elastic body and the position of the node portion are different in the front-back direction and the left-right direction in the radial direction, it is possible to easily perform tuning and the like.

[0120] Further, by designing the first communication holes formed in the first wall surface instead of the cylindrical member protruding from the first wall surface, it is possible to make the elastic force exhibited by the vibration isolation device different when a vibration in a lateral direction with respect to the direction in which the first regions are located with respect to the center axis is input and when a vibration in the lateral direction with respect to the direction in which the second regions are located with respect to the center axis is input, and thus it is less likely to be subject to design constraints compared to a case where the cylindrical member is designed to have such an effect.

[0121] The flow path cross-sectional area of the first communication hole opening in the first region and the flow path cross-sectional area of the first communication hole opening in the second region can be different from each other.

[0122] In this case, since the flow path cross-sectional area of the first communication hole opening in the first region and the flow path cross-sectional area of the first communication hole opening in the second region are different from each other, it is possible to reliably make the proportion of the opening area of the first communication hole in the planar area of the first region and the proportion of the opening area of the first communication hole in the planar area of the second region different from each other.

[0123] The interval between the first communication holes adjacent to each other in the first region and the interval between the first communication holes adjacent to each other in the second region can be different from each other.

[0124] In this case, since the interval between the first communication holes adjacent to each other in the first region and the interval between the first communication holes adjacent to each other in the second region are different from each other, it is possible to reliably make the proportion of the opening area of the first communication hole in the planar area of the first region and the proportion of the opening area of the first communication hole in the planar area of the second region different from each other.

[0125] The first regions can be respectively provided at positions opposite each other in one direction across the center axis when viewed in the axial direction, and the second regions can be respectively provided at positions opposite each other in another direction orthogonal to the one direction across the center axis.

[0126] In this case, the first regions are respectively provided at positions opposite each other in one direction across the center axis when viewed in the axial direction, and the second regions are respectively provided at positions opposite each other in another direction orthogonal to the one direction across the center axis. Thus, it is possible to reliably make the elastic force exhibited by the vibration isolation device different when a vibration in a lateral direction in the direction in which the first regions are located with respect to the center axis is input and when a vibration in a lateral direction in the direction in which the second regions are located with respect to the center axis is input.

[0127] In addition, the scope of the present application is not limited to the embodiments, and various modifications can be made without departing from the spirit of the present application.

[0128] For example, in the first embodiment, it can also be that the flow resistance of the liquid flowing in the first communication hole 42a opening in the second region Y is made lower than the flow resistance of the liquid flowing in the first communication hole 42a opening in the first region X, in a state where the proportion of the opening area of the first communication hole 42a in the planar area of the second region Y is kept smaller than the proportion of the opening area of the first communication hole 42a in the planar area of the first region X.

[0129] In the first embodiment, it can also be that the flow path cross-sectional area of the first communication hole 42a opening in the second region Y is made larger than or equal to the flow path cross-sectional area of the first communication hole 42a opening in the first region X, in a state where the proportion of the opening area of the first communication hole 42a in the planar area of the second region Y is kept smaller than the proportion of the opening area of the first communication hole 42a in the planar area of the first region X.

[0130] For example, in the first embodiment, it can also be that the flow resistance of the liquid flowing in the first communication hole 42a opening in the second region Y is made lower than the flow resistance of the liquid flowing in the first communication hole 42a opening in the first region X, in a state where the proportion of the opening area of the first communication hole 42a in the planar area of the second region Y is kept smaller than the proportion of the opening area of the first communication hole 42a in the planar area of the first region X.

[0131] In the first embodiment, it can also be that the flow path length of the first communication hole 42a opening in the first region X and the flow path length of the first communication hole 42a opening in the second region Y are made different from each other, for example, the flow path length of the first communication hole 42a opening in the first region X is made shorter than the flow path length of the first communication hole 42a opening in the second region Y.

[0132] In the first embodiment, it can also be that the total of the opening areas of the first communication holes 42a opening in the first region X is made smaller than the total of the opening areas of the first communication holes 42a opening in the second region Y, and the proportion of the opening area of the first communication hole 42a in the planar area of the first region X is made smaller than the proportion of the opening area of the first communication hole 42a in the planar area of the second region Y, in a state where the flow resistance of the liquid flowing in the first communication hole 42a opening in the first region X is kept lower than the flow resistance of the liquid flowing in the first communication hole 42a opening in the second region Y.

[0133] In the first embodiment, it is also possible that the total of the opening areas of the first communication holes 42a opening to the first region X is set to be smaller than the total of the opening areas of the first communication holes 42a opening to the second region Y, and the proportion of the opening areas of the first communication holes 42a in the planar area of the first region X is made smaller than the proportion of the opening areas of the first communication holes 42a in the planar area of the second region Y, in a state where the flow resistance of the liquid flowing in the first communication holes 42a opening to the first region X is lower than the flow resistance of the liquid flowing in the first communication holes 42a opening to the second region Y.

[0134] In the second embodiment, it is also possible that the flow path cross-sectional areas of the first communication holes 42a opening to the first region X and the flow path cross-sectional areas of the first communication holes 42a opening to the second region Y are different from each other. In the second embodiment, it is also possible that the proportion of the opening areas of the first communication holes 42a in the planar area of the second region Y and the proportion of the opening areas of the first communication holes 42a in the planar area of the first region X are different from each other.

[0135] In the second embodiment, it is also possible that the total of the opening areas of the first communication holes 42a opening to the first region X and the total of the opening areas of the first communication holes 42a opening to the second region Y are different from each other.

[0136] It is also possible that the flow resistance of the first communication holes 42a opening to the first region X is increased to the degree of the first communication holes 42a located on the second region Y side.

[0137] It is also possible that the flow resistance of the first communication holes 42a opening to the second region Y is decreased to the degree of the first communication holes 42a located on the first region X side.

[0138] It is also possible that the planar areas of the first region X and the second region Y are different from each other.

[0139] The number of the first region X and the second region Y is not limited to the embodiment, and can be appropriately changed. The positions of the first region X and the second region Y are not limited to the embodiment, and can be appropriately changed, for example, to positions where the first region X and the second region Y are respectively provided at positions opposite each other in one direction when viewed in the axial direction, and the like.

[0140] The first wall surface 16b is not limited to including the first region X and the second region Y, and can include other regions in which the first communication holes having a flow resistance of liquid different from the first communication holes 42a opening to the first region X and the second region Y are provided.

[0141] Also, the first communication holes 42a in which the liquid is contained in the first region X and the second region Y can be different from each other. For example, the first communication holes 42a in which the liquid is contained in the first region X can have a higher flow resistance than the first communication holes 42a in which the liquid is contained in the second region Y. Also, the first communication holes 42a in which the liquid is contained in the second region Y can have a lower flow resistance than the first communication holes 42a in which the liquid is contained in the first region X.

[0142] Further, although the tubular member 21 is shown as being joined to the first wall surface 16b in a manner not overlapping the first communication holes 42a, the tubular member 21 can be joined to the first wall surface 16b in a manner overlapping the first communication holes 42a.

[0143] Further, although the elastic body 13 is shown as being formed in a tubular shape extending in the axial direction, the elastic body 13 can be formed in a plate shape having a ring shape with upper and lower surfaces.

[0144] Further, although the recessed portion is formed in the upper wall surface of the partition member 16, the recessed portion can not be formed.

[0145] Further, in the embodiment, the compression-type vibration isolation device 1, 2 in which the positive pressure is applied to the main liquid chamber 14 by the support load is described, but the vibration isolation device can also be applied to a suspension-type vibration isolation device in which the main liquid chamber 14 is installed on the lower side in the vertical direction and the sub liquid chamber 15 is installed on the upper side in the vertical direction, and in which the negative pressure is applied to the main liquid chamber 14 by the support load.

[0146] Further, the vibration isolation device 1, 2 of the present application is not limited to being applied to the engine support of the vehicle, but can also be applied to devices other than the engine support. For example, the vibration isolation device can also be applied to a support of a generator mounted on a construction machine, or can also be applied to a support of a machine installed in a factory or the like.

[0147] Further, the configuration elements of the embodiment can be appropriately replaced with well-known configuration elements within the scope of the gist of the present application, and the embodiment and the modified example can also be appropriately combined.

[0148] (Third Embodiment)

[0149] Hereinafter, a third embodiment of the vibration isolation device of the present application will be described based on Figure 5 and Figure 6

[0150] As described above, the vibration isolation device of the present application can be applied to a vibration isolation device in which the main liquid chamber is installed on the lower side in the vertical direction and the sub liquid chamber is installed on the upper side in the vertical direction, and in which the negative pressure is applied to the main liquid chamber by the support load. Figure 5 ​As shown, the vibration isolation device 101 is a liquid-enclosed vibration isolation device that includes a first mounting member 111 that is cylindrical and is coupled to either one of a vibration generating portion and a vibration receiving portion, a second mounting member 112 that is coupled to the other one of the vibration generating portion and the vibration receiving portion, an elastic body 113 that elastically links the first mounting member 111 and the second mounting member 112 to each other, a partition member 116 that partitions a liquid chamber 119 in the first mounting member 111 in which a liquid is enclosed into a sub-liquid chamber 115 and a main-liquid chamber 114 that has the elastic body 113 in a portion of a partition wall, and a movable member 141 that is housed in a housing chamber 142 provided in the partition member 116 in a deformable or displaceable manner.

[0151] Hereinafter, a direction along a central axis O of the first mounting member 111 will be referred to as an axial direction. Further, a side on which the second mounting member 112 is located in the axial direction will be referred to as an upper side, and a side on which the partition member 116 is located will be referred to as a lower side. Further, when viewing the vibration isolation device 101 in plan view from the axial direction, a direction that intersects the central axis O will be referred to as a radial direction, and a direction that encircles the central axis O will be referred to as a circumferential direction.

[0152] Further, the first mounting member 111, the second mounting member 112, and the elastic body 113 each have a circular shape or a circular ring shape when viewed in plan view, and are disposed coaxially with the central axis O.

[0153] In a case where the vibration isolation device 101 is mounted on, for example, an automobile, the second mounting member 112 is coupled to an engine or the like as the vibration generating portion, and the first mounting member 111 is coupled to a vehicle body as the vibration receiving portion. Thus, transmission of vibration of the engine or the like to the vehicle body is suppressed. Further, the first mounting member 111 can be coupled to the vibration generating portion, and the second mounting member 112 can be coupled to the vibration receiving portion.

[0154] The first mounting member 111 includes an inner cylindrical portion 111a, an outer cylindrical portion 111b, and a lower support portion 111c. The inner cylindrical portion 111a is fitted into the outer cylindrical portion 111b. The lower support portion 111c is formed in a ring shape. An upper surface of an outer peripheral portion of the lower support portion 111c has a lower end opening rim of the outer cylindrical portion 111b placed thereon. The first mounting member 111 is formed as a whole in a cylindrical shape. The first mounting member 111 is coupled to the vehicle body or the like as the vibration receiving portion by means of a bracket that is not shown.

[0155] The second mounting member 112 is located radially inward of and upward of the first mounting member 111. An outer diameter of the second mounting member 112 is smaller than an inner diameter of the first mounting member 111. The second mounting member 112 is fitted into the inner side by a mounting metal fitting that is not shown, and is coupled to the engine or the like as the vibration generating portion by means of the mounting metal fitting.

[0156] Further, the relative positions of the first mounting member 111 and the second mounting member 112 are not limited to the illustrated example, and can be appropriately changed. Further, the outer diameter of the second mounting member 112 can be set to be equal to or greater than the inner diameter of the first mounting member 111.

[0157] The elastic body 113 is formed in a cylindrical shape extending in the axial direction. The elastic body 113 expands in diameter as it goes downward from the top.

[0158] The first mounting member 111 and the second mounting member 112 are respectively joined to both ends in the axial direction of the elastic body 113. The second mounting member 112 is joined to the upper end of the elastic body 113, and the first mounting member 111 is joined to the lower end of the elastic body 113. The elastic body 113 closes the upper end opening of the first mounting member 111. The lower end of the elastic body 113 is joined to the inner peripheral surface of the inner cylindrical portion 111a of the first mounting member 111. The upper end of the elastic body 113 is joined to the lower surface of the second mounting member 112. The elastic body 113 is formed of a rubber material or the like, and is vulcanization-bonded to the first mounting member 111 and the second mounting member 112. The thickness of the elastic body 113 decreases as it goes downward from the top. Further, the elastic body 113 can also be formed of a synthetic resin material or the like, for example.

[0159] A stopper rubber 113a covering the outer peripheral surface and the upper surface of the second mounting member 112 is integrally formed at the upper end of the elastic body 113. The outer housing 112a surrounding the second mounting member 112 is buried in the elastic body 113 and the stopper rubber 113a.

[0160] The diaphragm 120 is formed in a bottomed cylindrical shape of an elastic material such as rubber or soft resin. The upper end of the diaphragm 120 is sandwiched by the inner peripheral portion of the lower support portion 111c of the first mounting member 111 and the outer peripheral portion of the partition member 116, whereby the liquid tightness of the inside of the diaphragm 120 is ensured, and the lower end opening of the first mounting member 111 is closed.

[0161] Further, in the illustrated example, the bottom of the diaphragm 120 is shaped so as to be deeper on the outer peripheral side and shallower in the central portion. However, as the shape of the diaphragm 120, various shapes known in the art can be employed in addition to such a shape.

[0162] The lower end opening of the first mounting member 111 is closed by the diaphragm 120, and the upper end opening of the first mounting member 111 is closed by the elastic body 113 as described above, whereby the inside of the first mounting member 111 becomes a liquid chamber 119 that is liquid-tightly sealed. A liquid is enclosed (filled) in this liquid chamber 119. As the liquid, for example, glycol, water, silicone oil, or the like can be cited.

[0163] The liquid chamber 119 is divided into a main liquid chamber 114 and a sub liquid chamber 115 in the axial direction by the partition member 116. The main liquid chamber 114 has a partial inner peripheral surface 113c of the elastic body 113 in a partial region of the wall surface, and is a space surrounded by the elastic body 113 and the partition member 116, and the volume of which changes in accordance with the deformation of the elastic body 113. The sub liquid chamber 115 is a space surrounded by the diaphragm 120 and the partition member 116, and the volume of which changes in accordance with the deformation of the diaphragm 120. The vibration isolation device 101 including such a structure is a compression type device which is used in a manner that the main liquid chamber 114 is positioned on the upper side in the vertical direction and the sub liquid chamber 115 is positioned on the lower side in the vertical direction.

[0164] The partition member 116 is formed with a plurality of first communication holes 142a that communicate the main liquid chamber 114 and the accommodation chamber 142, and second communication holes 142b that communicate the sub liquid chamber 115 and the accommodation chamber 142. The partition member 116 is formed with a plurality of second communication holes 142b, and the number of the first communication holes 142a and the second communication holes 142b is the same as each other. Each of the first communication holes 142a and the second communication holes 142b is opposed to each other in the axial direction. The inner diameter (flow path cross-sectional area) of each of the first communication holes 142a and the second communication holes 142b opposed to each other in the axial direction is the same as each other. The flow path length of each of the first communication holes 142a and the second communication holes 142b opposed to each other in the axial direction is the same as each other. In addition, one second communication hole 142b can be formed in the partition member 116.

[0165] Here, in the partition member 116, the upper wall surface that constitutes a part of the inner surface of the main liquid chamber 114 and the lower wall surface that constitutes a part of the inner surface of the sub liquid chamber 115 are each in a circular shape that is coaxially arranged with the center axis O when viewed in the axial direction. The diameters of the upper wall surface and the lower wall surface of the partition member 116 are equal to each other. The upper wall surface of the partition member 116 is opposed to the inner peripheral surface 113c of the elastic body 113 in the axial direction, and the lower wall surface of the partition member 116 is opposed to the inner surface of the diaphragm 120 in the axial direction.

[0166] In the illustrated example, a dimple portion is formed in the entire region of the upper wall surface of the partition member 116 except for the outer peripheral portion 116a. The plurality of first communication holes 142a are opened in the entire region of the bottom surface (hereinafter referred to as a first wall surface) 116b of the dimple portion. A dimple portion is formed in the entire region of the lower wall surface of the partition member 116 except for the outer peripheral portion 116c. The plurality of second communication holes 142b are opened in the entire region of the bottom surface (hereinafter referred to as a second wall surface) 116d of the dimple portion. The dimple portions of the upper wall surface and the lower wall surface are each in a circular shape that is coaxially arranged with the center axis O when viewed in the axial direction, and the sizes of the inner diameters and depths of the respective dimple portions are equal to each other.

[0167] The storage chamber 142 is formed in the axial portion of the partition member 116 between the first wall surface 116b and the second wall surface 116d. The storage chamber 142 is circular in shape and coaxially aligned with the central axis O when viewed from the axial direction. The diameter of the storage chamber 142 is larger than the diameters of both the first wall surface 116b and the second wall surface 116d.

[0168] The movable member 141 is formed as a plate with its front and back surfaces facing axially. When viewed from the axial direction, the movable member 141 is circular in shape and is coaxially arranged with the central axis O. The movable member 141 is formed, for example, from an elastic material such as rubber or soft resin.

[0169] A throttling passage 124 is formed in the partition member 116, connecting the main liquid chamber 114 and the auxiliary liquid chamber 115. The throttling passage 124 is formed in the axial portion of the partition member 116 between the outer peripheral edge 116a of the upper wall and the outer peripheral edge 116c of the lower wall. The upper end of the throttling passage 124 is located above the first wall surface 116b, and the lower end is located below the second wall surface 116d. The cross-sectional shape of the throttling passage 124 is a rectangular shape that is longer in the axial direction. The resonant frequency of the throttling passage 124 is lower than the resonant frequencies of the first connecting hole 142a and the second connecting hole 142b.

[0170] like Figure 6 As shown, the opening 125 on the main liquid chamber 114 side of the throttling passage 124 is formed on the outer peripheral edge 116a of the upper wall of the partition member 116. This opening 125 is configured by multiple rows of holes 125b arranged circumferentially at intervals through through holes 125a, with different radial and circumferential positions. The inner diameter of the through hole 125a is smaller than the inner diameter of the first connecting hole 142a. Two rows of holes 125b are arranged on the outer peripheral edge 116a of the upper wall of the partition member 116. The circumferential offset and radial offset of each row of holes 125b are equal to the inner diameter of the through hole 125a.

[0171] The opening on the side of the auxiliary liquid chamber 115 of the throttling passage 124 is formed on the outer periphery 116c of the lower wall of the partition member 116. This opening has an area larger than the opening area of ​​the opening 125 on the side of the main liquid chamber 114, i.e., the sum of the opening areas of the plurality of through holes 125a. The openings 125 on the side of the main liquid chamber 114 and the auxiliary liquid chamber 115 of the throttling passage 124 are located radially outward from the first connecting hole 142a and the second connecting hole 142b.

[0172] A flange portion 116e is formed at the upper end portion of the partition member 116, and protrudes toward the radially outer side, continuously extending over the entire circumference. The upper surface of the flange portion 116e abuts against the lower end opening edge of each of the inner cylinder portion 111a and the outer cylinder portion 111b of the first mounting member 111, via the annular upper side sealing material 127. The lower surface of the flange portion 116e abuts against the upper surface of the inner circumferential portion of the lower support portion 111c of the first mounting member 111, via the upper end opening edge of the diaphragm 120 and the annular lower side sealing material 128 that surrounds the upper end opening edge of the diaphragm 120 from the radially outer side.

[0173] The partition member 116 includes an upper cylinder body 131 and a lower cylinder body 132 that are arranged facing each other in the axial direction, an upper wall 133 that closes the lower end opening portion of the upper cylinder body 131, and a lower wall 134 that closes the upper end opening portion of the lower cylinder body 132. In addition, the partition member 116 can also be integrally formed.

[0174] The upper end opening edge of the upper cylinder body 131 is the outer circumferential portion 116a of the upper wall surface of the aforementioned partition member 116. A flange portion 116e is formed at the upper end portion of the upper cylinder body 131. A circumferential groove is formed at a portion of the lower end opening edge of the upper cylinder body 131 that is located radially outward of the inner circumferential portion, the circumferential groove being recessed toward the upper side and opening toward the radially outer side.

[0175] The upper wall 133 is fixed to the inner circumferential portion of the lower end opening edge of the upper cylinder body 131. A first communication hole 142a is formed in the upper wall 133.

[0176] A circumferential groove recessed toward the lower side is formed at a radially intermediate portion of the upper end opening edge of the lower cylinder body 132 that is axially opposite to the circumferential groove of the upper cylinder body 131. A throttle passage 124 is formed divided by the circumferential groove and the circumferential groove of the upper cylinder body 131. The outer circumferential portion of the upper end opening edge of the lower cylinder body 132, which is located radially outward of the circumferential groove, abuts against the lower surface of the flange portion 116e of the upper cylinder body 131. The upper end portion of the diaphragm 120 is fitted into the upper end portion of the lower cylinder body 132, and the upper end portion of the diaphragm 120 is fitted into the lower support portion 111c of the first mounting member 111. Thus, the upper end portion of the diaphragm 120 is clamped in the radial direction by the outer circumferential surface of the lower cylinder body 132 and the inner circumferential surface of the lower support portion 111c.

[0177] The lower wall 134 is fixed to the inner circumferential portion of the upper end opening edge of the lower cylinder body 132. A second communication hole 142b is formed in the lower wall 134.

[0178] At least one of the inner circumferential portion of the lower end opening edge of the upper cylinder 131 and the inner circumferential portion of the upper end opening edge of the lower cylinder 132 is formed with an abutting protrusion 134a, 134b that protrudes toward the other and abuts against the other. In the example illustrated, the abutting protrusions 134a, 134b are formed at both the inner circumferential portion of the lower end opening edge of the upper cylinder 131 and the inner circumferential portion of the upper end opening edge of the lower cylinder 132. The abutting protrusions 134a, 134b are formed in a ring shape arranged coaxially with the center axis O, and the upper wall 133 and the lower wall 134 are arranged on the radially inner side of the abutting protrusions 134a, 134b in a state in which they are spaced apart from each other by a gap in the axial direction. The accommodation chamber 142 is formed by the lower surface of the upper wall 133, the upper surface of the lower wall 134, and the inner circumferential surface of the abutting protrusions 134a, 134b.

[0179] Further, in the present embodiment, the first wall surface 116b of the partition member 116, which is provided with the first communication hole 142a and constitutes a part of the inner surface of the main liquid chamber 114, is provided with a cylindrical member 121 that protrudes in the axial direction toward the elastic body 113.

[0180] The cylindrical member 121 is formed in a cylindrical shape and is arranged coaxially with the center axis O. The cylindrical member 121 extends straight in the axial direction. The length of the cylindrical member 121 in the axial direction is 20% or more of the maximum height T in the axial direction of the main liquid chamber 114. In the example illustrated, the maximum height T in the axial direction of the main liquid chamber 114 is the distance in the axial direction between the upper end portion of the inner circumferential surface 113c of the elastic body 113, which extends toward the radially inner side as it goes from the lower side toward the upper side, and the first wall surface 116b. The length of the cylindrical member 121 in the axial direction is set so that the upper end portion of the cylindrical member 121 does not abut against the inner circumferential surface 113c of the elastic body 113 when a static load in the axial direction is applied to the vibration isolation device 101 and when vibration in the axial direction is input.

[0181] Further, as described above, the inner circumferential surface 113c of the elastic body 113 is a portion that extends toward the radially inner side as it goes from the lower side toward the upper side, and in the case where the upper end portion of the inner surface of the elastic body 113, which divides the main liquid chamber 114, is provided with a recessed portion that is recessed toward the upper side as in the example illustrated, the upper end portion of the inner circumferential surface 113c of the elastic body 113 refers to the opening circumferential portion of the recessed portion of the inner surface of the elastic body 113.

[0182] The upper portion of the cylindrical member 121 protrudes upward from the upper end opening of the recessed portion formed in the upper wall surface of the partition member 116. The outer peripheral surface of the upper portion of the cylindrical member 121 opposes the lower end portion of the inner peripheral surface of the inner cylindrical portion 111a of the first mounting member 111 and the lower end portion of the inner peripheral surface 113c of the elastic body 113 with a gap provided in the radial direction. The protruding length of the upper portion of the cylindrical member 121 from the upper end opening of the recessed portion is shorter than the depth of the recessed portion. Further, the protruding length is shorter than the axial distance between the portion of the inner peripheral surface 113c of the elastic body 113 that opposes the upper end opening edge of the cylindrical member 121 in the axial direction and the upper end opening edge of the cylindrical member 121. The upper end opening edge of the cylindrical member 121 opposes the portion of the inner peripheral surface 113c of the elastic body 113 that extends toward the inside in the radial direction as it extends upward from below, which is offset downward from the central portion in the direction that extends from the inner peripheral surface 113c in the longitudinal cross section along the axial direction.

[0183] The cylindrical member 121 has an elliptical shape when viewed in the axial direction. The minimum value of the radius of the inner peripheral surface of the cylindrical member 121 is greater than the maximum value of the gap in the radial direction between the outer peripheral surface of the cylindrical member 121 and the inner peripheral surface of the recessed portion formed in the upper wall surface of the partition member 116. The maximum value of the inner diameter of the cylindrical member 121 is greater than half the maximum inner diameter R of the main liquid chamber 114. In the illustrated example, the maximum inner diameter R of the main liquid chamber 114 is the inner diameter of the lower end portion of the inner cylindrical portion 111a of the first mounting member 111. The planar area of the portion of the first wall surface 116b that is located inside the cylindrical member 121 (hereinafter referred to as the inside portion) 116f is smaller than the planar area of the portion that is located outside the cylindrical member 121 (hereinafter referred to as the outside portion) 116g.

[0184] The plurality of first communication holes 142a are opened in both the inside portion 116f and the outside portion 116g of the first wall surface 116b. The plurality of first communication holes 142a all oppose the upper surface of the movable member 141. The first communication holes 142a are provided in the entire area of the inside portion 116f and in the entire area of the circumferential direction of the outside portion 116g.

[0185] The cylindrical member 121 is joined to the portion of the first wall surface 116b that is located between adjacent first communication holes 142a in such a manner as not to overlap the first communication holes 142a.

[0186] The number of first communication holes 142a opened in the outside portion 116g is different from the number of first communication holes 142a opened in the inside portion 116f. In the illustrated example, the number of first communication holes 142a opened in the outside portion 116g is less than the number of first communication holes 142a opened in the inside portion 116f.

[0187] The proportion of the opening area of the first communication hole 142a in the planar area of the outer side portion 116g is different from the proportion of the opening area of the first communication hole 142a in the planar area of the inner side portion 116f. In the illustrated example, the proportion of the opening area of the first communication hole 142a in the planar area of the outer side portion 116g is smaller than the proportion of the opening area of the first communication hole 142a in the planar area of the inner side portion 116f. The total of the opening areas of the first communication holes 142a that open in the inner side portion 116f is larger than the total of the opening areas of the first communication holes 142a that open in the outer side portion 116g.

[0188] The flow path cross-sectional areas of the first communication holes 142a that open in the outer side portion 116g are the same as the flow path cross-sectional areas of the first communication holes 142a that open in the inner side portion 116f. Alternatively, the flow path cross-sectional areas of the first communication holes 142a that open in the outer side portion 116g can be different from the flow path cross-sectional areas of the first communication holes 142a that open in the inner side portion 116f.

[0189] The first communication holes 142a among the plurality of first communication holes 142a that open in the first wall surface 116b, other than the first communication holes 142a that are adjacent to each other in the radial direction across the cylindrical member 121, are all first communication holes 142a for which the intervals between first communication holes 142a that are adjacent to each other are equal to each other and smaller than the inner diameter of the first communication holes 142a. Alternatively, the intervals between first communication holes 142a that are adjacent to each other in the inner side portion 116f can be different from the intervals between first communication holes 142a that are adjacent to each other in the outer side portion 116g.

[0190] Here, the thicknesses of the upper wall 133 and the lower wall 134 are the same in the entire area, and the flow path lengths of the first communication holes 142a that open in the outer side portion 116g are the same as the flow path lengths of the first communication holes 142a that open in the inner side portion 116f. Alternatively, the flow path lengths of the first communication holes 142a that open in the outer side portion 116g can be different from the flow path lengths of the first communication holes 142a that open in the inner side portion 116f.

[0191] The flow resistance of the liquid that flows through the first communication holes 142a that open in the outer side portion 116g is the same as the flow resistance of the liquid that flows through the first communication holes 142a that open in the inner side portion 116f. Alternatively, the flow resistance of the liquid that flows through the first communication holes 142a that open in the outer side portion 116g can be different from the flow resistance of the liquid that flows through the first communication holes 142a that open in the inner side portion 116f.

[0192] It is also possible that one of the partition member 116 and the cylindrical member 121 forms an elastic force adjusting portion Z that makes the elastic force of the elastic body 113 different in the circumferential direction around the center axis O of the first mounting member 111. In the present embodiment, the cylindrical member 121 that forms the elastic force adjusting portion Z will be described.

[0193] Further, in the present embodiment, at least a portion of each of the inner peripheral surface of the elastic body 113 and the outer peripheral surface of the cylindrical member 121 opposes the other in the radial direction, and an annular gap 10X extending in the circumferential direction is partitioned. The width in the radial direction of one or more portions of the annular gap 10X in the circumferential direction is different from the width in the radial direction of other portions. The cylindrical member 121 that forms the elastic force adjusting portion Z is formed so that the width in the radial direction of one or more portions of the annular gap 10X in the circumferential direction is different from the width in the radial direction of other portions.

[0194] In the outer side portion 116g, the total of the opening areas of the first communication holes 142a that open in the portion located at the same position in the circumferential direction as the portion of the annular gap 10X in which the width in the radial direction is wider is greater than the total of the opening areas of the first communication holes 142a that open in the portion located at the same position in the circumferential direction as the portion of the annular gap 10X in which the width in the radial direction is narrower. Alternatively, the total of the opening areas of the former can be set to be less than the total of the opening areas of the latter.

[0195] In the illustrated example, as described above, the outer peripheral surface of the upper portion of the cylindrical member 121 opposes the lower end portion of the inner peripheral surface 113c of the elastic body 113 in a state in which a gap is provided in the radial direction, and the annular gap 10X is partitioned. In the annular gap 10X, the portions in which the width in the radial direction is the smallest are respectively provided at positions that oppose each other in one direction across the center axis O, and the portions in which the width in the radial direction is the largest are respectively provided at positions that oppose each other in another direction orthogonal to the one direction across the center axis O.

[0196] The shapes of the portions of each of the inner peripheral surface 113c of the elastic body 113 and the outer peripheral surface of the cylindrical member 121 that oppose each other in the radial direction are different from each other when viewed in the axial direction. The inner peripheral surface 113c of the elastic body 113 is circular in shape when viewed in the axial direction over the entire length in the axial direction, and the outer peripheral surface of the cylindrical member 121 is elliptical in shape when viewed in the axial direction over the entire length in the axial direction. The center axes of the portions of each of the inner peripheral surface 113c of the elastic body 113 and the outer peripheral surface of the cylindrical member 121 that oppose each other in the radial direction coincide with the center axis O of the first mounting member 111. The inner peripheral surface of the cylindrical member 121 is elliptical in shape when viewed in the axial direction over the entire length in the axial direction. The wall thickness of the cylindrical member 121 is uniform over the entire region.

[0197] The outer peripheral surface of the cylindrical member 121 has an elliptical shape in which the long axis extends in the one direction and the short axis extends in the other direction when viewed in the axial direction. The width of the annular gap 10X in the radial direction gradually changes with the position in the circumferential direction in such a manner that it is smallest between the end portion of the one direction of the outer peripheral surface of the cylindrical member 121 and the inner peripheral surface 113c of the elastic body 113 and is largest between the end portion of the other direction of the outer peripheral surface of the cylindrical member 121 and the inner peripheral surface 113c of the elastic body 113.

[0198] In the vibration isolation device 101 including such a structure, when the idling vibration, which is higher in frequency, among the low-frequency vibrations is input in the axial direction, the liquid chamber 119 and the movable member 141 deform or displace in the accommodation chamber 142 at the same time that the liquid of the liquid chamber 119 flows through the first communication hole 142a and the second communication hole 142b, thereby attenuating and absorbing the vibration. In addition, when the sway vibration, which is lower in frequency, among the low-frequency vibrations is input in the axial direction, the liquid of the liquid chamber 119 flows through the throttling passage 124, thereby attenuating and absorbing the vibration.

[0199] As described above, according to the vibration isolation device 101 of the present embodiment, since the cylindrical member 121 that protrudes toward the elastic body 113 is provided at the first wall surface 116b of the partition member 116, with the input of the mid-frequency vibration in the axial direction, when viewed in the longitudinal section along the axial direction, the portion of the elastic body 113 that is located on the first mounting member 111 side of the node portion that is generated in the central portion of the elastic body 113 in the past, for example, due to the liquid being difficult to flow between the inner peripheral surface of the main liquid chamber 114 and the outer peripheral surface of the upper portion of the cylindrical member 121, and the like, is shifted to the second mounting member 112 side, and in the elastic body 113, the portion that is located on the first mounting member 111 side of the node portion is more easily deformed than the portion that is located on the second mounting member 112 side of the node portion. Thus, with the input of the mid-frequency vibration in the axial direction, in the elastic body 113, the portion that is located on the first mounting member 111 side of the node portion is actively deformed, the rigidity of the elastic body 113 can be apparently reduced, and the vibration can be attenuated and absorbed.

[0200] In addition, since the plurality of first communication holes 142a are opened to both the inner side portion 116f and the outer side portion 116g of the first wall surface 116b, it is possible to arrange many first communication holes 142a in the first wall surface 116b, and for example, it is possible to reliably attenuate and absorb the idling vibration, which is higher in frequency, among the low-frequency vibrations, and the like.

[0201] Since the radial width of one or more portions of the annular gap 10X between the inner peripheral surface of the elastomer 113 and the outer peripheral surface of the cylindrical member 121 along the circumferential direction is different from the radial width of other portions, the flow state of the liquid at the time of input of vibration, for example, the flow rate, can be adjusted according to each position of the circumferential direction of the annular gap 10X. Thus, the position of the nodal portion generated in the elastomer 113 at the time of input of the medium-frequency vibration in the axial direction can be adjusted according to each position along the circumferential direction, and in addition, the degree of flow of the liquid in the annular gap 10X at the time of input of the medium-frequency vibration in the direction in which the portion in which the radial width of the annular gap 10X with respect to the center axis O is narrow (hereinafter referred to as a narrow-width portion) in the transverse direction intersecting the axial direction and the degree of flow of the liquid in the annular gap 10X at the time of input of the medium-frequency vibration in the direction in which the portion in which the radial width of the annular gap 10X with respect to the center axis O is wide (hereinafter referred to as a wide-width portion) in the transverse direction intersecting the axial direction can be made different, and the elastic property exhibited by the vibration isolation device 101 can be made different. That is, the cylindrical member 121 forming the elastic property adjustment portion Z can make the rigidity of the elastomer 113 in the circumferential direction around the center axis O of the first mounting member 111 appear to be different, that is, can make the elastic property (elasticity) of the elastomer 113 appear to be different. Thus, for example, even in the case where the elastic property of the elastomer 113 and the position of the nodal portion are different in the front-rear direction and the left-right direction in the radial direction, tuning and the like can be easily performed.

[0202] In addition, it can also be that the thickness or length of the elastomer 113 is made different in the front-rear direction and the left-right direction, for example, so as to make the elastic property of the elastomer 113 different.

[0203] Specifically, in the narrow-width portion of the annular gap 10X, the liquid is difficult to flow, and thus in the portion of the elastomer 113 located at the same circumferential position as the narrow-width portion at the time of input of the medium-frequency vibration in the axial direction, the nodal portion is relatively greatly shifted toward the second mounting member 112 side along the axial direction, and the elastic property exhibited by the vibration isolation device 101 is relatively high at the time of input of the medium-frequency vibration in the direction in which the narrow-width portion is located with respect to the center axis O in the transverse direction.

[0204] On the other hand, in the wide-width portion of the annular gap 10X, the liquid easily flows, and thus in the portion of the elastomer 113 located at the same circumferential position as the wide-width portion at the time of input of the medium-frequency vibration in the axial direction, the nodal portion is relatively slightly shifted toward the second mounting member 112 side along the axial direction, and the elastic property exhibited by the vibration isolation device 101 is relatively low at the time of input of the medium-frequency vibration in the direction in which the wide-width portion is located with respect to the center axis O in the transverse direction.

[0205] Since the shapes of the portions of the inner peripheral surface of the elastic body 113 and the outer peripheral surface of the cylindrical member 121 that are each opposed to each other in the radial direction are different from each other when viewed in the axial direction, the annular gap 10X in which the width in the radial direction at one or more portions along the circumferential direction is different from the width in the radial direction at other portions can be easily provided.

[0206] Since the central axes of the portions of the inner peripheral surface of the elastic body 113 and the outer peripheral surface of the cylindrical member 121 that are each opposed to each other in the radial direction are identical, the vibration isolation device 1 having the aforementioned effects can be easily obtained.

[0207] In the annular gap 10X, the portions having the smallest width in the radial direction are respectively provided at positions opposed to each other in one direction across the central axis O, and the portions having the largest width in the radial direction are respectively provided at positions opposed to each other in another direction orthogonal to the one direction across the central axis O. Thus, the elastic force exhibited by the vibration isolation device 101 can be reliably made different when a mid-frequency vibration in a direction in which the portion having the smallest width in the radial direction in the annular gap 10X with respect to the central axis O is input and when a mid-frequency vibration in a direction in which the portion having the largest width in the radial direction in the annular gap 10X with respect to the central axis O is input.

[0208] Further, since the length of the cylindrical member 121 in the axial direction is 20% or more of the maximum height T of the main liquid chamber 114 in the axial direction, axial mid-frequency vibrations can be reliably attenuated and absorbed.

[0209] Further, since the maximum value of the inner diameter of the cylindrical member 121 is more than half of the maximum inner diameter R of the main liquid chamber 114, axial mid-frequency vibrations can be reliably attenuated and absorbed.

[0210] The vibration isolation device according to one aspect of the present invention includes: a first mounting member and a second mounting member, the first mounting member being cylindrical and coupled to either of a vibration generating portion and a vibration receiving portion, the second mounting member being coupled to the other of the vibration generating portion and the vibration receiving portion; an elastic body elastically coupling the two mounting members; a partition member partitioning a liquid chamber in the first mounting member, in which a liquid is enclosed, into a sub-liquid chamber and a main-liquid chamber having the elastic body in a partial portion of a partition wall, in an axial direction along a central axis of the first mounting member; and a movable member accommodated in an accommodation chamber provided in the partition member in a deformable or displaceable manner, the partition member being provided with a throttle passage communicating the main-liquid chamber and the sub-liquid chamber, a plurality of first communication holes communicating the main-liquid chamber and the accommodation chamber, and a second communication hole communicating the sub-liquid chamber and the accommodation chamber, a first wall surface of the partition member, which is a portion of an inner surface of the main-liquid chamber and in which the first communication holes are provided, being provided with a cylindrical member protruding toward the elastic body in the axial direction, the plurality of first communication holes being opened in both an inner side portion inside the cylindrical member and an outer side portion outside the cylindrical member in the first wall surface, and one of the partition member and the cylindrical member forming a spring force adjustment portion that makes a spring force of the elastic body different in a circumferential direction around the central axis.

[0211] According to the vibration isolation device of one aspect of the present invention, since the cylindrical member protruding toward the elastic body is provided in the first wall surface of the partition member, with input of a mid-frequency vibration in the axial direction, when the elastic body is deformed in a secondary vibration mode in a longitudinal cross section along the axial direction, a node portion that is generated in a central portion of the elastic body in the related art is shifted to the second mounting member side, for example, due to difficulty of flow of the liquid between an inner peripheral surface of the main-liquid chamber and an outer peripheral surface of the cylindrical member, and a portion of the elastic body located on the first mounting member side than the node portion is easily deformed compared to a portion of the elastic body located on the second mounting member side than the node portion. Thus, with input of the mid-frequency vibration in the axial direction, the portion of the elastic body located on the first mounting member side than the node portion is actively deformed, the rigidity of the elastic body can be apparently reduced, and the vibration can be attenuated and absorbed.

[0212] Further, since the plurality of first communication holes are opened in both the inner side portion inside the cylindrical member and the outer side portion outside the cylindrical member in the first wall surface, a large number of the first communication holes can be arranged in the first wall surface, for example, and an idling vibration and the like, which is relatively high in frequency among low-frequency vibrations, can be reliably attenuated and absorbed.

[0213] Further, since one of the partition member and the tubular member forms the elastic force adjusting portion that makes the elastic force of the elastic body different in the circumferential direction around the center axis, it is possible to make the elastic force of the elastic body appear different in the circumferential direction around the center axis.

[0214] Also, the elastic body can be formed in a tubular shape extending in the axial direction,

[0215] At least a part of each of the inner peripheral surface of the elastic body and the outer peripheral surface of the tubular member faces the other in the radial direction, and a ring-shaped gap extending in the circumferential direction around the center axis is partitioned,

[0216] The tubular member forming the elastic force adjusting portion is formed so that the radial width of one or more portions in the circumferential direction in the ring-shaped gap is different from the radial width of the other portions.

[0217] In this case, since the tubular member forming the elastic force adjusting portion is formed so that the radial width of one or more portions in the circumferential direction in the ring-shaped gap is different from the radial width of the other portions, that is, the radial width of one or more portions in the circumferential direction in the ring-shaped gap between the inner peripheral surface of the elastic body and the outer peripheral surface of the tubular member is different from the radial width of the other portions, it is possible to adjust the flow state of the liquid at the time of input of vibration, for example, the flow rate, according to each position in the circumferential direction of the ring-shaped gap. Thus, it is possible to adjust the position of the nodal portion generated in the elastic body at the time of input of mid-frequency vibration in the axial direction according to each position in the circumferential direction, and further, to make the degree of flow of the liquid in the ring-shaped gap different at the time of input of mid-frequency vibration in the direction in which the portion in which the radial width of the ring-shaped gap with respect to the center axis is narrow (hereinafter referred to as a narrow-width portion) is located and at the time of input of mid-frequency vibration in the direction in which the portion in which the radial width of the ring-shaped gap with respect to the center axis is wide (hereinafter referred to as a wide-width portion) is located, and to make the elastic force exhibited by the vibration isolation device appear different. Thus, for example, even in the case where the elastic force of the elastic body and the position of the nodal portion are different in the front-rear direction and the left-right direction in the radial direction, it is possible to easily perform tuning and the like.

[0218] Specifically, in the narrow-width portion of the ring-shaped gap, the liquid is difficult to flow, and thus at the time of input of mid-frequency vibration in the axial direction, the nodal portion is relatively largely shifted toward the second mounting member side in the portion in the elastic body located in the same circumferential direction as the narrow-width portion, and the elastic force exhibited by the vibration isolation device is high at the time of input of mid-frequency vibration in the transverse direction in the direction in which the narrow-width portion is located with respect to the center axis.

[0219] On the other hand, in the wide portion of the annular gap, liquid easily flows, and thus, when a mid-frequency vibration in the axial direction is input, the portion of the elastic body located in the same circumferential direction as the wide portion is less displaced toward the second mounting member side in the axial direction, and when a mid-frequency vibration in the lateral direction with respect to the direction in which the wide portion is located with respect to the center axis is input, the vibration isolation device exhibits lower elastic force.

[0220] Also, the shapes of the portions of the inner circumferential surface of the elastic body and the outer circumferential surface of the cylindrical member that face each other in the radial direction can be different from each other when viewed from the axial direction.

[0221] In this case, since the shapes of the portions of the inner circumferential surface of the elastic body and the outer circumferential surface of the cylindrical member that face each other in the radial direction are different from each other when viewed from the axial direction, the annular gap in which the width in the radial direction of a portion or portions in the circumferential direction is different from the width in the radial direction of other portions can be easily provided.

[0222] Also, the center axes of the portions of the inner circumferential surface of the elastic body and the outer circumferential surface of the cylindrical member that face each other in the radial direction can coincide with each other.

[0223] In this case, since the center axes of the portions of the inner circumferential surface of the elastic body and the outer circumferential surface of the cylindrical member that face each other in the radial direction coincide with each other, the vibration isolation device having the aforementioned effects can be easily obtained.

[0224] Also, in the annular gap, the portions having the smallest width in the radial direction can be respectively provided at positions facing each other in one direction across the center axis, and the portions having the largest width in the radial direction can be respectively provided at positions facing each other in another direction orthogonal to the one direction across the center axis.

[0225] In this case, in the annular gap, the portions having the smallest width in the radial direction are respectively provided at positions facing each other in one direction across the center axis, and the portions having the largest width in the radial direction are respectively provided at positions facing each other in another direction orthogonal to the one direction across the center axis. Thus, the elastic force exhibited by the vibration isolation device when a mid-frequency vibration in the lateral direction with respect to the direction in which the portion having the smallest width in the radial direction in the annular gap is located with respect to the center axis is input and the elastic force exhibited by the vibration isolation device when a mid-frequency vibration in the lateral direction with respect to the direction in which the portion having the largest width in the radial direction in the annular gap is located with respect to the center axis is input can be reliably made different.

[0226] In addition, the scope of the present application is not limited to the embodiments, and various modifications can be made without departing from the spirit of the present application.

[0227] For example, the inner peripheral surface 113c of the elastic body 13 and the outer peripheral surface of the cylindrical member 121 can each have a shape that is the same as that of the other when viewed in the axial direction, and the center axes of the respective portions can be eccentric.

[0228] For example, the outer peripheral surface of the cylindrical member 121 can have a circular shape when viewed in the axial direction, and the inner peripheral surface 113c of the elastic body 113 can have an elliptical shape or a square shape or a non-circular shape other than a circular shape.

[0229] In the embodiment, the inner peripheral surface of the cylindrical member 121 can have a circular shape when viewed in the axial direction. That is, the wall thickness of the cylindrical member 121 can be different at one or a plurality of portions along the circumferential direction, so that the radial width of one or a plurality of portions along the circumferential direction in the annular gap 10X is different from the radial width of other portions.

[0230] The radial width of the annular gap 10X can be different, for example, only at one or a plurality of portions along the circumferential direction from that of other portions.

[0231] As the annular gap 10X, for example, a structure in which the portion having the smallest radial width and the portion having the largest radial width are provided at positions opposite each other in one direction across the center axis O, or the like, can be employed.

[0232] The outer peripheral surface of the cylindrical member 121 can be opposed to the inner peripheral surface 113c of the elastic body 113 with a gap provided in the radial direction in the entire area.

[0233] In the embodiment, a structure in which the shapes of the outer peripheral surface of the cylindrical member 121 and the first wall surface 116b are different from each other when viewed in the axial direction is shown, but the shapes thereof can be the same as each other.

[0234] The number of the first communication holes 142a that are open to the outer side portion 116g can be greater than the number of the first communication holes 142a that are open to the inner side portion 116f.

[0235] The proportion of the opening area of the first communication holes 142a in the planar area of the outer side portion 116g can be greater than the proportion of the opening area of the first communication holes 142a in the planar area of the inner side portion 116f.

[0236] In the embodiment, the sum of the opening areas of the first communication holes 142a opening at the inner side portion 116f is made larger than the sum of the opening areas of the first communication holes 142a opening at the outer side portion 116g, but is not limited thereto, and for example, the sum of the opening areas of the first communication holes 142a opening at the inner side portion 116f can be set to be smaller than the sum of the opening areas of the first communication holes 142a opening at the outer side portion 116g.

[0237] Further, the structure in which the cylindrical member 121 is joined to the first wall surface 116b in a manner not to overlap the first communication holes 142a is shown, but the cylindrical member 121 can be joined to the first wall surface 116b so as to overlap the first communication holes 142a.

[0238] Further, the dimple portion is formed in the upper wall surface of the partition member 116, but the dimple portion can not be formed.

[0239] Further, in the embodiment, the compression type vibration isolation device 101 in which a positive pressure is applied to the main liquid chamber 114 due to the support load is described, but the vibration isolation device can also be applied to a suspension type vibration isolation device in which the main liquid chamber 114 is installed on the lower side in the vertical direction and the sub liquid chamber 115 is installed on the upper side in the vertical direction, and a negative pressure is applied to the main liquid chamber 114 due to the support load.

[0240] Further, the vibration isolation device 101 of the present application is not limited to be applied to the engine support of the vehicle, and can be applied to devices other than the engine support. For example, the vibration isolation device can be applied to a support of a generator mounted on a construction machine, or can be applied to a support of a machine installed in a factory or the like.

[0241] Further, the configuration elements of the embodiment can be appropriately replaced with well-known configuration elements within a range not departing from the gist of the present application, and further, the embodiment and the modified example can be appropriately combined.

[0242] The scope of protection of the present application is not limited to the first to third embodiments described above, and various modifications can be made to the first to third embodiments within a range not departing from the gist of the present application. For example, the configuration elements of the first to third embodiments can be appropriately combined within a range not departing from the gist of the present application.

[0243] Industrial applicability

[0244] According to the present application, a middle frequency vibration can be attenuated and absorbed.

[0245] Explanation of reference numerals

[0246] 1, 2, 101, vibration isolation device; 11, 111, first mounting member; 12, 112, second mounting member; 13, 113, elastic body; 14, 114, main liquid chamber; 15, 115, sub liquid chamber; 16, 116, partition member; 16b, 116b, first wall surface; 16f, 116f, inner side portion; 16g, 116g, outer side portion; 19, 119, liquid chamber; 21, 121, cylindrical member; 24, 124, throttle passage; 41, 141, movable member; 42, 142, accommodation chamber; 42a, 142a, first communication hole; 42b, 142b, second communication hole; O, central axis; X, first region; Y, second region; Z, elastic force adjusting portion; 10X, annular gap.

Claims

1. A vibration isolation device, wherein the vibration isolation device includes: a first mounting member that is cylindrical, is linked to either one of a vibration generating portion and a vibration receiving portion, and a second mounting member that is linked to the other one of the vibration generating portion and the vibration receiving portion; an elastic body that elastically links the two mounting members; a partition member that divides a liquid chamber in the first mounting member, in which a liquid is enclosed, into a sub-liquid chamber and a main-liquid chamber having the elastic body in a partial portion of a partition wall, in an axial direction along a central axis of the first mounting member; and a movable member that is housed in a housing chamber provided in the partition member, in a manner that is deformable or displaceable, a throttle passage that communicates the main-liquid chamber and the sub-liquid chamber, a plurality of first communication holes that communicate the main-liquid chamber and the housing chamber, and a second communication hole that communicates the sub-liquid chamber and the housing chamber are formed in the partition member, a first wall surface that is a portion of an inner surface of the main-liquid chamber and in which the first communication holes are opened is provided with a cylindrical member that protrudes toward the elastic body in the axial direction, the plurality of first communication holes are opened in both an inner side portion that is on an inner side of the cylindrical member and an outer side portion that is on an outer side of the cylindrical member in the first wall surface, one of the partition member and the cylindrical member forms a spring force adjusting portion that makes an apparent difference in spring force of the elastic body in a circumferential direction around the central axis, the first wall surface includes a first region in the circumferential direction around the central axis and a second region that is provided at a position different from the first region in the circumferential direction, a flow path cross-sectional area of the first communication hole that is opened in the first region and a flow path cross-sectional area of the first communication hole that is opened in the second region are different from each other, in the first wall surface, the plurality of first communication holes are opened in the inner side portion of the cylindrical member, the elastic body is formed in a cylindrical shape that extends in the axial direction, at least a portion of each of an inner peripheral surface of the elastic body and an outer peripheral surface of the cylindrical member faces the other in a radial direction, and an annular gap that extends in the circumferential direction around the central axis is partitioned, the cylindrical member that forms the spring force adjusting portion is formed so that a radial width of one or a plurality of portions in the annular gap in the circumferential direction is different from a radial width of other portions.

2. The vibration isolation device according to claim 1, wherein in the partition member that forms the spring force adjusting portion, a flow resistance of a liquid that flows through the first communication hole that is opened in the first region and the first communication hole that is opened in the second region in the first wall surface is different from each other.

3. The vibration isolation device according to claim 2, wherein a flow path length of the first communication hole that is opened in the first region and the first communication hole that is opened in the second region in the first wall surface is different from each other.

4. The vibration isolation device according to claim 2 or 3, wherein The proportion of the opening area of the first communication hole in the planar area of the first region and the proportion of the opening area of the first communication hole in the planar area of the second region are different from each other.

5. The vibration isolation device according to claim 2 or 3, wherein The first regions are respectively provided at positions opposite each other in one direction across the center axis when viewed in the axial direction, and the second regions are respectively provided at positions opposite each other in another direction orthogonal to the one direction across the center axis.

6. The vibration isolation device according to claim 1, wherein In the partition member that forms the elastic force adjustment portion, A plurality of the first communication holes are respectively provided in the first regions and the second regions in the first wall surface, The proportion of the opening area of the first communication hole in the planar area of the first region and the proportion of the opening area of the first communication hole in the planar area of the second region are different from each other.

7. The vibration isolation device according to claim 6, wherein The flow path cross-sectional area of the first communication hole that opens in the first region and the flow path cross-sectional area of the first communication hole that opens in the second region are different from each other.

8. The vibration isolation device according to claim 6 or 7, wherein The interval between the first communication holes adjacent to each other in the first regions and the interval between the first communication holes adjacent to each other in the second regions are different from each other.

9. The vibration isolation device according to claim 6 or 7, wherein The first regions are respectively provided at positions opposite each other in one direction across the center axis when viewed in the axial direction, and the second regions are respectively provided at positions opposite each other in another direction orthogonal to the one direction across the center axis.

10. The vibration isolation device according to claim 1, wherein The shapes of the portions of the inner peripheral surface of the elastic body and the outer peripheral surface of the cylindrical member that respectively face each other in the radial direction are different from each other when viewed in the axial direction.

11. The vibration isolation device according to claim 1 or 10, wherein The center axes of the portions of the inner peripheral surface of the elastic body and the outer peripheral surface of the cylindrical member that respectively face each other in the radial direction coincide with each other.

12. The vibration isolation device according to claim 1 or 10, wherein The portions of the annular gap in which the radial width is the smallest are respectively provided at positions opposite each other in one direction across the center axis, and the portions of the annular gap in which the radial width is the largest are respectively provided at positions opposite each other in another direction orthogonal to the one direction across the center axis.

Images