JP7326120B2 - Anti-vibration device - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an anti-vibration device that is applied to, for example, automobiles, industrial machinery, etc., and that absorbs and attenuates vibrations of vibration-generating parts such as engines.

As a vibration isolator of this type, conventionally, a cylindrical first mounting member connected to one of the vibration generating portion and the vibration receiving portion, and a second cylindrical mounting member connected to the other, are used. an elastic body for elastically connecting the mounting members; a partition member for dividing the liquid chamber in the first mounting member containing the liquid into a main liquid chamber and a secondary liquid chamber having the elastic body as a part of the partition; a movable member accommodated deformably or displaceably in a storage chamber provided in the member; an orifice passage connecting the main liquid chamber and the sub-liquid chamber in the partition member; and the main liquid chamber and the storage chamber. and a second communication hole communicating between the auxiliary liquid chamber and the storage chamber.
In this anti-vibration device, when idle vibration with a relatively high frequency among low-frequency vibrations with a frequency of less than 200 Hz is input in the axial direction, the movable member is deformed or displaced in the housing chamber, and the liquid in the liquid chamber is displaced. is passed through the first communicating hole and the second communicating hole to attenuate and absorb idling vibration, and when shake vibration with a relatively low frequency is input in the axial direction, the liquid in the liquid chamber is , orifice passages to attenuate and absorb shake vibrations.

JP-A-2002-327789

However, the conventional anti-vibration device cannot attenuate or absorb medium-frequency vibrations of 200 Hz to 1000 Hz.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a vibration isolator capable of damping and absorbing medium-frequency vibrations.

A vibration isolator according to the present invention comprises a cylindrical first mounting member connected to one of a vibration generating portion and a vibration receiving portion, a cylindrical second mounting member connected to the other, and both of these mounting members. and a liquid chamber in the first mounting member, which is filled with liquid, is connected to the main liquid chamber and the sub-liquid chamber having the elastic body as a part of the partition wall, and the first mounting member. and a movable member accommodated in a housing chamber provided in the partition member so as to be deformable or displaceable, wherein the partition member includes the main liquid chamber and the An orifice passage that communicates with the secondary liquid chamber, a plurality of first communication holes that communicate with the main liquid chamber and the storage chamber, and a second communication hole that communicates with the secondary liquid chamber and the storage chamber. A tubular member that is formed in the partition member and protrudes in the axial direction toward the elastic body on a first wall surface that the first communication hole opens and that constitutes a part of the inner surface of the main liquid chamber. is provided, and the plurality of first communication holes are open to both an inner portion located inside the tubular member and an outer portion located outside the tubular member on the first wall surface, Either one of the outer peripheral surface and the inner peripheral surface of the tubular member is formed through a step portion so that the thickness of the tubular member becomes thinner toward the second mounting member side along the axial direction. It is formed in a step-like shape with a diameter that changes over time.

According to the present invention, since the cylindrical member protruding toward the elastic body is arranged on the first wall surface of the partition member, when intermediate-frequency vibration is input in the axial direction, , when the elastic body deforms in the secondary vibration mode, the node portion that has conventionally occurred in the central portion of the elastic body is, for example, between the inner peripheral surface of the main liquid chamber and the outer peripheral surface of the cylindrical member. Due to the fact that the liquid of the elastic body becomes difficult to flow, the elastic body is shifted toward the second mounting member side, and the elastic body is located closer to the second mounting member side than the joint portion. The portion located on the member side is easily deformed. As a result, when intermediate-frequency vibrations are input in the axial direction, the portion of the elastic body positioned closer to the first mounting member than the node portion is actively deformed, and the apparent rigidity of the elastic body can be reduced. , and this vibration can be damped and absorbed.
In addition, since the plurality of first communication holes are open to both the inner portion located inside the tubular member and the outer portion located outside the tubular member in the first wall surface, It becomes possible to arrange many first communication holes, and for example, among low-frequency vibrations, it is possible to reliably attenuate and absorb relatively high-frequency idling vibrations.
Further, either one of the outer peripheral surface and the inner peripheral surface of the tubular member is provided through the stepped portion so that the thickness of the tubular member becomes thinner as it goes toward the second mounting member side along the axial direction. Since it is formed in a stepped shape with a varying diameter, the flow state, such as the flow velocity, of the liquid between the inner peripheral surface of the main liquid chamber, the tip opening edge of the cylindrical member, and the stepped portion can be adjusted, and each position of the plurality of joint portions generated in the elastic body can be adjusted when the elastic body deforms in a high-order vibration mode with the input of medium-frequency vibration.

The diameter of either one of the outer peripheral surface and the inner peripheral surface of the tubular member may be the same over the entire length in the axial direction.

In this case, the diameter of the other of the outer peripheral surface and the inner peripheral surface of the tubular member is the same over the entire length in the axial direction. It becomes possible to ensure the thickness of the base end portion side, and it is possible to prevent deterioration in durability.

The entire cylindrical member may be integrally formed.

In this case, since the entire cylindrical member is integrally formed, it becomes easier to ensure the strength of the cylindrical member, and deterioration in durability can be easily suppressed.

According to the present invention, intermediate frequency vibration can be damped and absorbed.

1 is a vertical cross-sectional view of a vibration isolator according to an embodiment of the present invention; FIG. FIG. 2 is a cross-sectional view of the anti-vibration device shown in FIG. 1 taken along the line AA.

An embodiment of a vibration isolator according to the present invention will be described below with reference to FIGS. 1 and 2. FIG.
As shown in FIG. 1, the vibration isolator 1 includes a cylindrical first mounting member 11 connected to one of the vibration generating portion and the vibration receiving portion, and a mounting member 11 connected to the other of the vibration generating portion and the vibration receiving portion. The second mounting member 12 to be connected, the elastic body 13 that elastically connects the first mounting member 11 and the second mounting member 12 to each other, and the liquid chamber 19 in the first mounting member 11 in which the liquid is sealed are A partition member 16 partitioning a main liquid chamber 14 and a sub-liquid chamber 15 having an elastic body 13 as a part of the partition wall, and a movable member 41 housed in a storage chamber 42 provided in the partition member 16 so as to be deformable or displaceable. and a liquid-enclosed vibration isolator.

Hereinafter, the direction along the central axis O of the first mounting member 11 is referred to as the axial direction. In addition, the side of the second mounting member 12 along the axial direction is called the upper side, and the side of the partition member 16 is called the lower side. Further, in a planar view of the vibration isolator 1 viewed from the axial direction, the direction intersecting the central axis O is called the radial direction, and the direction rotating around the central axis O is called the circumferential direction.
The first mounting member 11, the second mounting member 12, and the elastic body 13 each have a circular shape or an annular shape in plan view, and are arranged coaxially with the central axis O. As shown in FIG.

When this anti-vibration device 1 is installed in an automobile, for example, the second mounting member 12 is connected to an engine or the like as a vibration generating portion, and the first mounting member 11 is connected to the vehicle body as a vibration receiving portion. This suppresses transmission of vibrations of the engine or the like to the vehicle body. Alternatively, the first mounting member 11 may be connected to the vibration generating portion and the second mounting member 12 may be connected to the vibration receiving portion.

The first mounting member 11 includes an inner cylinder portion 11a, an outer cylinder portion 11b, and a lower support portion 11c.
The inner tubular portion 11a is fitted into the outer tubular portion 11b. The lower support portion 11c is formed in an annular shape. A lower opening edge of the outer cylindrical portion 11b is placed on the upper surface of the outer peripheral portion of the lower support portion 11c. The first mounting member 11 is formed in a cylindrical shape as a whole. The first mounting member 11 is connected to a vehicle body or the like as a vibration receiving portion via a bracket (not shown).

The second mounting member 12 is positioned radially inside and above the first mounting member 11 . 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 connected to an engine or the like as a vibration generating section via a mounting bracket (not shown) fitted inside.
Note that the relative positions of the first mounting member 11 and the second mounting member 12 are not limited to the illustrated example and may be changed as appropriate. Also, the outer diameter of the second mounting member 12 may be equal to or greater than the inner diameter of the first mounting member 11 .

The elastic body 13 is formed in a tubular shape extending in the axial direction. The elastic body 13 expands in diameter from top to bottom.
A first mounting member 11 and a second mounting member 12 are separately connected to both ends of the elastic body 13 in the axial direction. The second mounting member 12 is connected to the upper end of the elastic body 13 , and the first mounting member 11 is connected to the lower end of the elastic body 13 . The elastic body 13 closes the upper end opening of the first mounting member 11 . A lower end portion of the elastic body 13 is connected to the inner peripheral surface of the inner cylindrical portion 11 a of the first mounting member 11 . The upper end of the elastic body 13 is connected to the lower surface of the second mounting member 12 . The elastic body 13 is made of a rubber material or the like, and is vulcanized and bonded to the first mounting member 11 and the second mounting member 12 . The thickness of the elastic body 13 decreases from top to bottom. Note that the elastic body 13 may be formed of, for example, a synthetic resin material.
A stopper rubber 13 a is formed integrally with the upper end portion of the elastic body 13 to cover the outer peripheral surface and the upper surface of the second mounting member 12 . An outer shell 12a surrounding the second mounting member 12 is embedded in the elastic body 13 and the stopper rubber 13a.

The diaphragm 20 is made of an elastic material such as rubber or soft resin, and is formed in a cylindrical shape with a bottom. The upper end portion of the diaphragm 20 is sandwiched between 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, thereby ensuring liquid tightness inside the diaphragm 20, and A lower end opening of the first mounting member 11 is closed.
In the illustrated example, the bottom portion of the diaphragm 20 is deep at the outer peripheral side and shallow at the central portion. However, as the shape of the diaphragm 20, various conventionally known shapes can be adopted besides such a shape.

The diaphragm 20 closes the lower end opening of the first mounting member 11, and as described above, the elastic body 13 closes the upper end opening of the first mounting member 11, so that the inside of the first mounting member 11 is liquid-tight. The liquid chamber 19 is sealed with A liquid is enclosed (filled) in the liquid chamber 19 . Liquids include, for example, ethylene glycol, water, or silicone oil.

The liquid chamber 19 is axially partitioned into a main liquid chamber 14 and a sub liquid chamber 15 by a partition member 16 . The main liquid chamber 14 has an inner peripheral surface 13c of the elastic body 13 as part of its wall surface, is a space surrounded by the elastic body 13 and the partition member 16, and changes its internal volume as the elastic body 13 deforms. . The sub-liquid chamber 15 is a space surrounded by the diaphragm 20 and the partition member 16 , and its internal volume changes as the diaphragm 20 deforms. The anti-vibration device 1 having such a configuration is a compression-type device that is mounted so that the main liquid chamber 14 is positioned vertically upward and the auxiliary liquid chamber 15 is positioned vertically downward. .

The partition member 16 is formed with a plurality of first communication holes 42a communicating between the main liquid chamber 14 and the storage chamber 42, and second communication holes 42b communicating between the secondary liquid chamber 15 and the storage chamber 42. . A plurality of second communication holes 42b are formed in the partition member 16, and the numbers of the first communication holes 42a and the numbers of the second communication holes 42b are the same. The respective first communication holes 42a and second communication holes 42b face each other in the axial direction. The inner diameters (flow passage cross-sectional areas) of the first communication hole 42a and the second communication hole 42b, which face each other in the axial direction, are the same. The channel lengths of the first communication hole 42a and the second communication hole 42b, which face each other in the axial direction, are the same. One second communication hole 42 b may be formed in the partition member 16 .

Here, in the partition member 16, the upper wall surface forming a part of the inner surface of the main liquid chamber 14 and the lower wall surface forming a part of the inner surface of the sub-liquid chamber 15 each have a central axis O when viewed from the axial direction. It has a circular shape arranged coaxially with the 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 faces the inner peripheral surface 13c of the elastic body 13 in the axial direction, and the lower wall surface of the partition member 16 faces the inner surface of the diaphragm 20 in the axial direction.

In the illustrated example, the upper wall surface of the partition member 16 is formed with a recess over the entire area except for the outer peripheral edge portion 16a. A plurality of first communication holes 42a are open over the entire bottom surface (hereinafter referred to as first wall surface) 16b of the recess. A depression is formed in the lower wall surface of the partition member 16 over the entire area except for the outer peripheral edge 16c. A plurality of second communication holes 42b are open over the entire bottom surface (hereinafter referred to as a second wall surface) 16d of this recessed portion. Each depression on the upper wall surface and the lower wall surface has a circular shape arranged coaxially with the central axis O when viewed from the axial direction, and the sizes such as the inner diameter and depth of each depression are equal to each other. .

The storage chamber 42 is formed in a portion of the partition member 16 located between the first wall surface 16b and the second wall surface 16d in the axial direction. The housing chamber 42 has a circular shape coaxial with the central axis O when viewed from the axial direction. The diameter of the storage chamber 42 is larger than each diameter of the first wall surface 16b and the second wall surface 16d.
The movable member 41 is formed in a plate shape with front and back surfaces facing the axial direction. The movable member 41 has a circular shape arranged coaxially with the central axis O when viewed from the axial direction. The movable member 41 is made of an elastic material such as rubber or soft resin.

An orifice passage 24 that communicates the main liquid chamber 14 and the sub-liquid chamber 15 is formed in the partition member 16 . The orifice passage 24 is formed in a portion of the partition member 16 located between the outer peripheral edge portion 16a of the upper wall surface and the outer peripheral edge portion 16c of the lower wall surface in the axial direction. The upper end of the orifice passage 24 is located above the first wall surface 16b, and the lower end of the orifice passage 24 is located below the second wall surface 16d. The cross-sectional shape of the orifice passage 24 is a rectangular shape elongated in the axial direction. The resonance frequency of the orifice passage 24 is lower than the resonance frequencies of the first communication hole 42a and the second communication hole 42b.

As shown in FIG. 2 , the opening 25 of the orifice passage 24 on the side of the main liquid chamber 14 is formed in the outer peripheral edge 16 a of the upper wall surface of the partition member 16 . The opening 25 is formed by arranging a plurality of hole rows 25b in which a plurality of through holes 25a are arranged at intervals in the circumferential direction at different positions in the radial direction and the circumferential direction. The inner diameter of the through hole 25a is smaller than the inner diameter of the first communication hole 42a. Two hole rows 25 b are arranged on the outer peripheral edge portion 16 a of the upper wall surface of the partition member 16 . The amount of displacement in the circumferential direction of each row of holes 25b and the amount of displacement in the radial direction of each row of holes 25b are equal to the inner diameter of the through hole 25a.

The opening of the orifice passage 24 on the side of the secondary liquid chamber 15 is formed in the outer peripheral edge portion 16c of the lower wall surface of the partition member 16, and the opening area of the opening 25 on the side of the main liquid chamber 14, that is, the opening of the plurality of through holes 25a It is one opening whose opening area is larger than the sum of the areas. The opening 25 of the orifice passage 24 on the side of the main liquid chamber 14 and the opening on the side of the sub-liquid chamber 15 are located radially outside the first communication hole 42a and the second communication hole 42b.

An upper end portion of the partition member 16 is formed with a flange portion 16e that protrudes radially outward and continuously extends over the entire circumference. The upper surface of the flange portion 16 e abuts the lower opening edges of the inner cylinder portion 11 a and the outer cylinder portion 11 b of the first mounting member 11 via an annular upper seal member 27 . The lower surface of the flange portion 16e is formed on the upper surface of the inner peripheral portion of the lower support portion 11c of the first mounting member 11, the upper opening edge of the diaphragm 20, and the annular lower surface surrounding the upper opening edge of the diaphragm 20 from the outside in the radial direction. They are in contact with each other via a sealing material 28 .

The partition member 16 includes an upper cylinder 31 and a lower cylinder 32 which are arranged facing each other in the axial direction, an upper wall 33 closing the lower end opening of the upper cylinder 31, and an upper end opening of the lower cylinder 32. a lower wall 34 that closes the . In addition, the partition member 16 may be integrally formed.

The upper end opening edge of the upper cylindrical body 31 forms the outer peripheral edge portion 16a of the upper wall surface of the partition member 16 described above. A flange portion 16 e is formed at the upper end portion of the upper cylindrical body 31 . A peripheral groove that is recessed upward and is open radially outward is formed in a portion of the lower opening edge of the upper cylinder 31 located radially outward from the inner peripheral portion.
The upper wall 33 is fixed to the inner peripheral portion of the lower end opening edge of the upper cylindrical body 31 . A first communication hole 42 a is formed in the upper wall 33 .

A circumferential groove recessed downward is formed in a radially intermediate portion of the upper end opening edge of the lower cylindrical body 32 that faces the circumferential groove of the upper cylindrical body 31 in the axial direction. The orifice passage 24 is defined by this circumferential groove and the circumferential groove of the upper cylindrical body 31 . At the upper end opening edge of the lower cylinder 32 , the outer peripheral edge located radially outside the circumferential groove abuts the lower surface of the flange portion 16 e of the upper cylinder 31 . The lower cylindrical body 32 is fitted into the upper end portion of the diaphragm 20 , and the upper end portion of the diaphragm 20 is fitted into the lower support portion 11 c of the first mounting member 11 . Thereby, the upper end portion of the diaphragm 20 is radially sandwiched between the outer peripheral surface of the lower cylindrical body 32 and the inner peripheral surface of the lower support portion 11c.
The lower wall 34 is fixed to the inner peripheral portion of the upper opening edge of the lower cylindrical body 32 . A second communication hole 42b is formed in the lower wall 34 .

At least one of the inner peripheral portion of the lower opening edge of the upper cylinder 31 and the inner peripheral portion of the upper opening edge of the lower cylinder 32 is formed with abutment projections 34a and 34b that protrude toward and abut on the other. ing. In the illustrated example, abutting protrusions 34a and 34b are formed on both the inner periphery of the lower opening edge of the upper cylinder 31 and the inner periphery of the upper opening edge of the lower cylinder 32 . The abutment projections 34a and 34b are annularly arranged coaxially with the central axis O, and the upper wall 33 and the lower wall 34 are arranged radially inwardly of the projections 34a and 34b with a gap therebetween in the axial direction. It is The accommodation chamber 42 is defined by the lower surface of the upper wall 33, the upper surface of the lower wall 34, and the inner peripheral surfaces of the abutment projections 34a and 34b.

In this embodiment, in the partition member 16 , the first communication hole 42 a is open and protrudes in the axial direction toward the elastic body 13 on the first wall surface 16 b forming part of the inner surface of the main liquid chamber 14 . A cylindrical member 21 is provided for the purpose.

The cylindrical member 21 is formed in a cylindrical shape and arranged coaxially with the central axis O. As shown in FIG. The inner peripheral surface of the tubular member 21 extends straight in the axial direction. The inner diameter of the cylindrical member 21 is the same over the entire length in the axial direction. The axial length of the cylindrical member 21 is 20% or more of the maximum axial height T of the main liquid chamber 14 . In the illustrated example, the maximum axial height T of the main liquid chamber 14 is the upper end portion of the inner peripheral surface 13c of the elastic body 13 extending radially inward as it goes upward from below, and the first It is the distance in the axial direction from the wall surface 16b. The length of the tubular member 21 in the axial direction is such that the upper end portion of the tubular member 21 becomes an elastic body when a static load in the axial direction is applied to the vibration isolator 1 and when vibration in the axial direction is input. 13 is set so as not to come into contact with the inner peripheral surface 13c.
As described above, the inner peripheral surface 13c of the elastic body 13 is a portion that extends radially inward as it goes upward from below. As in the illustrated example, when the upper end portion of the inner surface of the elastic body 13 that defines the main liquid chamber 14 is provided with a recess that is recessed upward, the recess in the inner surface of the elastic body 13 It is the opening peripheral part of the part.

The upper portion of the tubular member 21 protrudes upward from the upper end opening of the depression formed in the upper wall surface of the partition member 16 . The outer peripheral surface of the upper portion of the tubular member 21 radially faces the lower end portion of the inner peripheral surface of the inner tubular portion 11 a of the first mounting member 11 and the lower end portion of the inner peripheral surface 13 c of the elastic body 13 . The projection length of the upper part of the cylindrical member 21 from the upper end opening of the recessed portion is longer than the depth of this recessed portion. Moreover, the protrusion length is determined by the portion of the inner peripheral surface 13c of the elastic body 13 where the upper end opening edge (tip opening edge) 21a of the tubular member 21 faces in the axial direction, and the upper end opening edge 21a of the tubular member 21 . and less than the axial distance of . Of the inner peripheral surface 13c of the elastic body 13 extending inward in the radial direction from the bottom to the top, in a vertical cross-sectional view along the axial direction, below the central portion in the extending direction of the inner peripheral surface 13c The upper end opening edge 21a of the tubular member 21 axially faces the shifted portion.

The radius of the inner peripheral surface of the tubular member 21 is larger than the radial distance between the outer peripheral surface of the tubular member 21 and the inner peripheral surface of the recess formed in the upper wall surface of the partition member 16 . The inner diameter of the cylindrical member 21 is half or more of 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 tubular portion 11 a of the first mounting member 11 . In the first wall surface 16b, the plane area of the portion (hereinafter referred to as the inner portion) 16f located inside the tubular member 21 is the plane area of the portion (hereinafter referred to as the outer portion) 16g located outside the tubular member 21. greater than

The plurality of first communication holes 42a are open to both the inner portion 16f and the outer portion 16g of the first wall surface 16b. All of the plurality of first communication holes 42 a face the upper surface of the movable member 41 .
The tubular member 21 is connected to a portion of the first wall surface 16b located between adjacent first communication holes 42a, and is arranged so as not to overlap with the first communication holes 42a. The cylindrical member 21 is arranged so that its outer peripheral surface is in contact with the first communication hole 42a when viewed from the axial direction.

The number of first communication holes 42a opening to the outer portion 16g and the number of first communication holes 42a opening to the inner portion 16f are different from each other. In the illustrated example, the number of first communication holes 42a opening to the outer portion 16g is smaller than the number of first communication holes 42a opening to the inner portion 16f.
The ratio of the opening area of the first communication holes 42a to the plane area of the outer portion 16g and the ratio of the opening area of the first communication holes 42a to the plane area of the inner portion 16f are different from each other. In the illustrated example, the ratio of the opening area of the first communication holes 42a to the plane area of the outer portion 16g is smaller than the ratio of the opening area of the first communication holes 42a to the plane area of the inner portion 16f.
The total opening area of the first communication holes 42a opening to the inner portion 16f is larger than the total opening area of the first communication holes 42a opening to the outer portion 16g.

The channel cross-sectional area of the first communication hole 42a that opens to the outer portion 16g and the channel cross-sectional area of the first communication hole 42a that opens to the inner portion 16f are the same. Note that the cross-sectional area of the first communication hole 42a that opens to the outer portion 16g and the cross-sectional area of the first communication hole 42a that opens to the inner portion 16f may be different from each other.

For all of the plurality of first communication holes 42a opened in the first wall surface 16b, the intervals between adjacent first communication holes 42a are equal to each other and smaller than the inner diameter of the first communication holes 42a. In the inner portion 16f, the interval between adjacent first communication holes 42a may be different from the interval between adjacent first communication holes 42a in the outer portion 16g.

A plurality of first communication holes 42a opening in the outer portion 16g are arranged at equal intervals in the circumferential direction over the entire circumferential length of the outer portion 16g.
In the inner portion 16f, a plurality of first communication holes 42a are arranged at equal intervals in the circumferential direction, and the rows of the first communication holes 42a arranged in the circumferential direction are arranged at equal intervals in the radial direction. A plurality of are arranged concentrically around the central axis O with a space between them.

Here, the thickness of each of the upper wall 33 and the lower wall 34 is the same over the entire area, and the channel length of the first communicating hole 42a opening to the outer portion 16g and the first communicating hole 42a opening to the inner portion 16f The channel lengths of the holes 42a are the same as each other. Note that the channel length of the first communication hole 42a that opens to the outer portion 16g and the channel length of the first communication hole 42a that opens to the inner portion 16f may be different from each other.
The flow resistance of the liquid flowing through the first communication hole 42a opening in the outer portion 16g is the same as the flow resistance of the liquid flowing through the first communication hole 42a opening in the inner portion 16f. The flow resistance of the liquid flowing through the first communication hole 42a opening in the outer portion 16g and the flow resistance of the liquid flowing through the first communication hole 42a opening in the inner portion 16f may be different from each other.

In the present embodiment, the outer peripheral surface of the tubular member 21 is arranged through the stepped portion 21b so that the thickness of the tubular member 21 becomes thinner as it goes upward (toward the second mounting member along the axial direction). It is formed in a stepped shape with a reduced diameter. The entire tubular member 21 is integrally formed. In the cylindrical member 21, the widths in the radial direction of the upper end opening edge 21a and the step portion 21b that are continuous with the inner peripheral surface are the same. A plurality of stepped portions 21b are provided at different positions in the axial direction, and the radial widths of the stepped portions 21b are the same. The axial distance between the stepped portions 21b adjacent to each other in the radial direction and the axial distance between the stepped portions 21b adjacent to each other in the radial direction and the upper end opening edge 21a of the tubular member 21 are the same. .

In the anti-vibration device 1 having such a configuration, when the idle vibration having a relatively high frequency among the low-frequency vibrations is input in the axial direction, the movable member 41 is deformed or displaced in the housing chamber 42, causing the liquid to move. This vibration is damped and absorbed by the liquid in the chamber 19 flowing through the first communication hole 42a and the second communication hole 42b. When shake vibration, which has a relatively low frequency among low-frequency vibrations, is input in the axial direction, the liquid in the liquid chamber 19 flows through the orifice passage 24, thereby attenuating and absorbing this vibration.

As described above, according to the vibration isolator 1 according to the present embodiment, the cylindrical member 21 projecting toward the elastic body 13 is disposed on the first wall surface 16b of the partition member 16. When the elastic body 13 is deformed in the secondary vibration mode in the vertical cross-sectional view along the axial direction with the input of the intermediate frequency vibration in the direction, the node portion that was conventionally generated in the central part of the elastic body 13 is For example, the liquid between the inner peripheral surface of the main liquid chamber 14 and the outer peripheral surface of the upper portion of the cylindrical member 21 becomes difficult to flow, and thus the liquid is shifted toward the second mounting member 12, resulting in the elastic body. In 13, the portion positioned closer to the first mounting member 11 than the joint portion is more likely to deform than the portion positioned closer to the second mounting member 12 than the joint portion. As a result, when intermediate-frequency vibrations are input in the axial direction, the portion of the elastic body 13 located closer to the first mounting member 11 than the node portion is actively deformed, and the apparent rigidity of the elastic body 13 is reduced. It is possible to attenuate and absorb this vibration.

Also, since the plurality of first communication holes 42a are open to both the inner portion 16f and the outer portion 16g of the first wall surface 16b, many first communication holes 42a can be arranged on the first wall surface 16b. Thus, among low-frequency vibrations, for example, idling vibrations with relatively high frequencies can be reliably damped and absorbed.

In addition, since the outer peripheral surface of the cylindrical member 21 is formed in a stepped shape that decreases in diameter via the step portion 21b as it goes upward, the inner peripheral surface of the main liquid chamber 14 and the upper end of the cylindrical member 21 It is possible to adjust the flow state of the liquid, for example, the flow velocity, between the opening edge 21a and the stepped portion 21b located radially outside therefrom. When the elastic body 13 deforms in a high-order vibration mode, each position of the plurality of joint portions generated in the elastic body 13 can be adjusted.
Since the outer peripheral surface of the tubular member 21 is formed in a stepped shape, the liquid between the inner peripheral surface of the main liquid chamber 14, the upper end opening edge 21a of the tubular member 21, and the stepped portion 21b is removed. In addition to the flow state of the liquid between the inner peripheral surface of the main liquid chamber 14 and the outer peripheral surface of the upper portion of the cylindrical member 21, it is possible to adjust the flow state of the liquid, effectively damping the intermediate frequency vibration. , can be absorbed.

Since the inner diameter of the cylindrical member 21 is uniform over the entire length in the axial direction, it is possible to secure the wall thickness of the cylindrical member 21 on the lower end side connected to the first wall surface 16b. A decrease in durability can be prevented.
Since the entire tubular member 21 is integrally formed, the strength of the tubular member 21 can be easily ensured, and deterioration in durability can be easily suppressed.

In addition, since the axial length of the cylindrical member 21 is 20% or more of the maximum axial height T of the main fluid chamber 14, it is possible to reliably attenuate and absorb axial intermediate frequency vibrations. can be done.
Further, since the inner diameter of the tubular member 21 is half or more of the maximum inner diameter R of the main liquid chamber 14, it is possible to reliably attenuate and absorb intermediate frequency vibrations in the axial direction.

The technical scope of the present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the scope of the present invention.

For example, a cylindrical member having only one stepped portion 21b or three or more stepped portions 21b may be employed.
The cylindrical member 21 is composed of, for example, a plurality of cylindrical bodies that are fitted in layers in the radial direction, and that have longer axial lengths as they are positioned further inward in the radial direction. and is the longest in the axial direction as the upper end opening edge 21a of the cylindrical member 21, and the upper end opening edge of the cylindrical body positioned radially outside the cylindrical member 21a is the step A configuration of the portion 21b may be employed. This configuration also has the same effects as those of the anti-vibration device 1 of the above-described embodiment.
The radial widths of the upper opening edge 21a and the step portion 21b of the tubular member 21 may be different from each other.
The axial distance between the radially adjacent stepped portions 21b and the axial distance between the radially adjacent stepped portions 21b and the upper opening edge 21a of the tubular member 21 may be different from each other. .

As the cylindrical member 21, the inner peripheral surface of the cylindrical member 21 has a stepped shape whose diameter is increased via a stepped portion so that the thickness of the cylindrical member 21 becomes thinner as it goes upward (toward the second mounting member along the axial direction). may be formed.
Also in this configuration, it is possible to adjust the flow state of the liquid between the inner peripheral surface of the main liquid chamber 14, the upper end opening edge of the cylindrical member, and the stepped portion located radially inward from this. is possible, and when the elastic body 13 is deformed in a high-order vibration mode with the input of medium-frequency vibration, each position of the plurality of joint portions generated in the elastic body 13 can be adjusted.
In this configuration, the outer diameter of the cylindrical member may be the same over the entire length in the axial direction.
In this configuration as well, it is possible to ensure the thickness of the lower end portion of the cylindrical member connected to the first wall surface 16b, thereby preventing deterioration in durability.

The number of first communication holes 42a opening to the outer portion 16g may be greater than or equal to the number of first communication holes 42a opening to the inner portion 16f.
The ratio of the opening area of the first communication holes 42a to the plane area of the outer portion 16g may be equal to or greater than the ratio of the opening area of the first communication holes 42a to the plane area of the inner portion 16f.
In the above-described embodiment, the total opening area of the first communication holes 42a opening to the inner portion 16f is larger than the total opening area of the first communication holes 42a opening to the outer portion 16g. The total opening area of the first communication holes 42a opening to the inner portion 16f may be less than or equal to the total opening area of the first communication holes 42a opening to the outer portion 16g.

Further, although the configuration in which the tubular member 21 is connected to the first wall surface 16b so as not to overlap the first communication hole 42a is shown, the tubular member 21 is connected to the first wall surface 16b so as not to overlap the first communication hole 42a. may be overlapped and concatenated.
Further, although the elastic body 13 is formed in a cylindrical shape extending in the axial direction, it may be formed in a ring-like plate shape having upper and lower surfaces.
Also, although the recessed portion is formed in the upper wall surface of the partition member 16, the recessed portion may not be formed.

Further, in the above embodiment, the compression-type vibration isolator 1 in which a positive pressure acts on the main fluid chamber 14 due to the application of a supporting load has been described, but the main fluid chamber 14 is positioned vertically downward and It can also be applied to a suspension type anti-vibration device in which the sub-liquid chamber 15 is mounted vertically upward and negative pressure acts on the main liquid chamber 14 when a supporting load acts.

Moreover, the vibration isolator 1 according to the present invention is not limited to the engine mount of a vehicle, and can be applied to other than the engine mount. For example, it can be applied to the mount of a generator mounted on a construction machine, or it can be applied to the mount of a machine installed in a factory or the like.

In addition, it is possible to appropriately replace the components in the above-described embodiments with known components without departing from the scope of the present invention, and the above-described embodiments and modifications may be combined as appropriate.

1 Vibration isolator 11 First mounting member 12 Second mounting member 13 Elastic body 14 Main liquid chamber 15 Sub liquid chamber 16 Partition member 16b First wall surface 16f Inner portion 16g Outer portion 19 Liquid chamber 21 Cylindrical member 21a Top opening edge 21b Stepped portion 24 Orifice passage 41 Movable member 42 Accommodating chamber 42a First communicating hole 42b Second communicating hole O Center axis

Claims (3)

a cylindrical first mounting member connected to one of the vibration generating portion and the vibration receiving portion, and a second cylindrical mounting member connected to the other;
an elastic body that elastically connects these mounting members;
A partition that divides a liquid chamber in the first mounting member in which the liquid is sealed into a main liquid chamber and a sub liquid chamber having the elastic body as a part of the partition wall in an axial direction along the central axis of the first mounting member. a member;
a movable member housed in a housing chamber provided in the partition member so as to be deformable or displaceable;
The partition member includes an orifice passage communicating the main liquid chamber and the secondary liquid chamber, a plurality of first communication holes communicating the main liquid chamber and the storage chamber, and the secondary liquid chamber and the storage chamber. and a second communication hole communicating with the
In the partition member, a tubular member projecting in the axial direction toward the elastic body is disposed on a first wall surface on which the first communication hole opens and which constitutes a part of the inner surface of the main liquid chamber. is,
The plurality of first communication holes open to both an inner portion located inside the tubular member and an outer portion located outside the tubular member on the first wall surface,
Either one of the outer peripheral surface and the inner peripheral surface of the tubular member is formed through a step portion so that the thickness of the tubular member becomes thinner toward the second mounting member side along the axial direction. An anti-vibration device formed in a staircase shape with a diameter that varies from step to step. 2. The vibration damping device according to claim 1, wherein the diameter of the other of the outer peripheral surface and the inner peripheral surface of said cylindrical member is the same over the entire length in the axial direction. 3. The vibration isolator according to claim 1, wherein the tubular member is integrally formed as a whole.

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