JPH0518434A - Vibration isolating device - Google Patents

Abstract

PURPOSE:To absorb vibrations certainly by furnishing a resilient body between an inner and an outer cylinder, forming a pressure receiving liquid chamber in a part of this resilient body, providing an aux. liquid chamber isolated from the liquid chamber. forming an air chamber with a resilient film which constitutes part of the aux. liquid chamber, and by making part of the bulkhead of the pressure receiving liquid chamber from No.2 rigid film having a higher rigidity in the central part than the perimeter. CONSTITUTION:A resilient body 34 is provided between an outer cylinder 16 and an inner cylinder 31, and the outer cylinder 16 is partitioned into a pressure receiving liquid chamber 48 and an aux. liquid chamber 44 by a bulkhead as a part of the resilient body 34, wherein the aux. liquid chamber 44 is formed part of the bulkhead with No.1 diaphragm 26. The pressure receiving liquid chamber 48 and aux. liquid chamber 44 are put in communication through a restrictive passage 54, and part of the bulkhead of the pressure receiving liquid chamber 48 is formed with No.2 diaphragm 24. This diaphragm 24 has a higher rigidity in the central part than at the perimeter, and therein a communication hole 56 is formed whose one side is coupled directly with the air chamber 52 and the other side connected to a negative pressure means. Another air chamber 27 is formed between the diaphragm 26 and the outer cylinder 16, while the first named air chamber 52 is bounded by the diaphragm 24 and outer cylinder 16. Thereby both shake vibrations and idling vibration can be absorbed effectively.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid-filled bush type vibration damping device which absorbs vibrations from a vibration generating portion such as an engine.

[0002]

2. Description of the Related Art A liquid-filled type vibration damping device is used as a vibration damping device for absorbing engine vibrations and running vibrations of a vehicle.

In this vibration isolator, the pressure receiving liquid chamber and the sub liquid chamber are communicated with each other by a limiting passage, and when vibrating, the vibration is absorbed by the passage resistance of the liquid and the liquid column resonance in the limiting passage. Further, when the vibration has a high frequency, the restriction passage is in a clogged state, so that a vibration plate or the like for expanding and contracting the pressure receiving liquid chamber is provided. However, in this type of vibration damping device, the vibration plate or the like may move due to hydraulic pressure during low-perimeter vibration, so that the movement of the liquid in the restricted passage is reduced, and the vibration absorption effect due to the passage resistance of the liquid may be reduced. ..

[0004]

SUMMARY OF THE INVENTION In consideration of the above facts, an object of the present invention is to provide a vibration isolator capable of reliably absorbing vibration of a desired frequency.

[0005]

A vibration isolator according to the present invention comprises a mounting member which is connected to one of a vibration generating portion or a vibration receiving portion and has an insertion portion, an outer cylinder which is inserted and arranged in the insertion portion, and a vibration. At least an inner cylinder connected to the other of the generating section or the vibration receiving section, an elastic body provided between the inner cylinder and the outer cylinder and deforming when vibration occurs, and the elastic body provided in the outer cylinder. A pressure receiving liquid chamber that can be expanded and contracted as a part of the partition wall, a sub liquid chamber that is provided in the outer cylinder and is separated from the pressure receiving liquid chamber, and a part of the partition wall of the sub liquid chamber that is provided in the outer cylinder. A first elastic film that forms a part, a limiting passage that is provided in the outer cylinder and connects the pressure receiving liquid chamber and the sub liquid chamber, and a part of a partition wall of the pressure receiving liquid chamber that is provided in the outer cylinder. An air chamber is formed between the mounting member and the mounting member, and the shape of the surface on the mounting member side is that of the mounting member. A second elastic membrane stiffness is configured higher than the are and the central portion shape along the peripheral surface outer peripheral portion,
The mounting member is provided at a position facing the central portion of the second elastic film, and one is connected to the air chamber and the other is connected to a negative pressure means for making the air chamber a negative pressure. And a communication hole.

[0006]

In the vibration isolator of the present invention, for example, when the mounting member is connected to the vibration receiving portion such as the vehicle body of the vehicle and the inner cylinder is connected to the vibration generating portion such as the engine, the vibration is generated in the inner cylinder, the elastic body and the outer body. It is supported by a vibration generating unit such as a vehicle body via a cylinder and a mounting member.
At this time, the vibration is absorbed by the resistance based on the internal friction of the elastic body.

When the frequency of vibration is less than the predetermined frequency,
By making the inside of the first air chamber negative by the negative pressure means, the second diaphragm is closely fixed to the inner wall surface of the second air chamber. In this state, when the inner cylinder moves due to vibration and the elastic body is deformed, the pressure receiving liquid chamber generates a high expansion / contraction force, liquid moves back and forth in the restriction passage, and resistance and liquid column when the liquid passes through the restriction passage A large damping coefficient can be obtained by resonance, and vibrations below a predetermined frequency are effectively absorbed.

On the other hand, when the vibration frequency is equal to or higher than the predetermined frequency, the inside of the second air chamber is not brought into a negative pressure state by the pressure varying means. As a result, the second diaphragm can be elastically deformed away from the inner wall of the second air chamber, the second air chamber can be expanded and contracted, and the pressure rise in the pressure receiving liquid chamber can be suppressed.
Reduce the spring constant of the anti-vibration device. As a result, vibrations of a predetermined frequency or higher are effectively absorbed.

[0009]

【Example】

[First Embodiment] A first embodiment of the vibration isolator 10 according to the present invention will be described with reference to FIGS.

As shown in FIG. 1, the anti-vibration device 10 is provided with a bracket 12 for mounting on a vehicle body (not shown).
Has been inserted. In this embodiment, the outer cylinder 16
After being press-fitted or inserted into the annular portion 14, both ends of the annular portion 14 are caulked inward to form the annular portion 1.
However, the outer cylinder 16 may be fixed to the annular portion 14 only by press-fitting the outer cylinder 16 into the annular portion 14.

As shown in FIG. 2, the outer cylinder 16 has a rectangular hole 18 formed on the upper side and a rectangular hole 20 formed on the lower side. A thin rubber layer 22 is vulcanized and adhered to the inner peripheral surface of the outer cylinder 16, and the thin rubber layer 22 has a portion corresponding to the rectangular hole 18 protruding inward to form a diaphragm 24. Corresponding portions project inward to form the diaphragm 26.

The diaphragm 24 has a thick portion 2 corresponding to the rectangular hole 18 and has a central portion thicker than the thin rubber layer 22.
It is supposed to be 8. The thick portion 28 has a rectangular shape in a plan view, and a cross section perpendicular to the axis line is formed in an arc shape along the inner peripheral surface of the annular portion 14. Therefore, the thick portion 28 can be brought into close contact with the inner peripheral surface of the annular portion 14 when it abuts. A peripheral portion of the thick portion 28 is a movable portion 30 having a substantially U-shaped cross section and having a thickness substantially the same as that of the thin rubber layer 22, and the movable portion 30 includes the thick portion 28 and the thin rubber layer 22. Are integrally formed. Since the thick portion 28 is formed thicker than the movable portion 30, it has high rigidity and is hard to be deformed. In the free state of the diaphragm 24, the thick portion 28 is separated from the inner peripheral surface of the annular portion 14 as shown by the imaginary line in FIG.
An air chamber 52 is formed between the air chamber 52 and 6.

On the other hand, the overall thickness of the diaphragm 26 is substantially the same as that of the thin rubber layer 22. Therefore, the rigidity is lower than that of the diaphragm 24, and the diaphragm 24 is easily deformed. The space between the diaphragm 26 and the outer cylinder 16 is an air chamber 27. The air chamber 27 may have a hole (not shown) formed in the annular portion 14 of the bracket 12 to communicate with the outside.

As shown in FIGS. 1 and 2, a cylindrical block 32 is inserted in the outer cylinder 16. The block 32 is formed of an elastic body 34, and the outer periphery in the radial direction is in close contact with the thin rubber layer 22. An intermediate cylinder 36 is disposed inside the block 32 coaxially with the outer cylinder 16, and the intermediate cylinder 36 is vulcanized and bonded to the elastic body 34. The intermediate cylinder 36 is formed of a steel plate or the like, and both ends in the axial direction of the intermediate cylinder 36 are expanded diameter parts 38 and intermediate parts in the axial direction are small diameter parts 40. It is arranged via the rubber layer 22. In this embodiment, the block 32 is fixed in the outer cylinder 16 by inserting it into the outer cylinder 16 and squeezing the outer cylinder 16 and then crimping both ends of the outer cylinder 16 inward.

Further, the block 32 has an inner cylinder 31 arranged substantially in the center thereof along the axis. Like the intermediate cylinder 36, the inner cylinder 31 is also vulcanized and bonded to the elastic body 34.

The intermediate cylinder 3 is attached to the elastic body 34 of the block 32.
A concave portion 42 is formed on the lower side of 6 and at an intermediate portion in the axial direction. The recess 42 is formed by the thin rubber layer 22 on the inner peripheral surface of the outer cylinder 16.
Also, the auxiliary liquid chamber 44 is constituted by being surrounded by the diaphragm 26.

Further, the elastic body 34 of the block 32 is provided with a recess 46 on the upper side of the inner cylinder 31 and at the axially intermediate portion. The recess 46 is formed by the thin rubber layer 2 on the inner peripheral surface of the outer cylinder 16.
The pressure receiving liquid chamber 48 is surrounded by the diaphragm 2 and the diaphragm 24.

Further, the elastic body 34 of the block 32 is
A hollow portion 50 is formed so as to penetrate along the axial direction of the inner cylinder 31 between the sub liquid chamber 44 and the inner cylinder 31, so that the inner cylinder 31 can easily move in the direction in which the inner cylinder 31 comes into contact with and separates from the pressure receiving liquid chamber 48. There is.

A groove 48 is formed on the outer periphery of the block 32 at an intermediate portion in the axial direction. One end of this groove 48 is connected to the pressure receiving liquid chamber 48 and the other end thereof is connected to the auxiliary liquid chamber 44, and the outer side in the radial direction is closed by the outer cylinder 16, whereby the limiting passage 54 is formed. Is forming. Therefore,
The pressure receiving liquid chamber 48 and the sub liquid chamber 40 communicate with each other via a restriction passage 54. The pressure receiving liquid chamber 48 and the auxiliary liquid chamber 44 are
And the limiting passage 54 is filled with a liquid such as water or oil.

On the other hand, a communication hole 56 is formed in the annular portion 14 of the bracket 12 so as to correspond to the air chamber 52,
A pipe 58 is attached to the annular portion 14 so as to correspond to the communication hole 56. In this embodiment, the pipe 58
The joint portion of the and the annular portion 14 is fixed by welding all around or brazing.

One end of a connecting pipe 60 is connected to the pipe 58, and the other end of the connecting pipe 60 is connected to a 3-port / 2-position switching valve 62. In addition to the connecting pipe 60, one end of a pipe 64 and one end of an atmosphere communication pipe 66 are connected to the three-port two-position switching valve 62. The other end of the pipe 64 is connected to an intake manifold 68 of an engine (not shown), and the other end of the atmosphere communication pipe 66 is connected to the atmosphere. The 3-port 2-position switching valve 62 is connected to the control means 70 to control switching. The control means 60 is driven by the vehicle power supply and can detect the vehicle speed and the engine speed by receiving the detection signals from at least the vehicle speed sensor 72 and the engine speed sensor 74. As a result, the control means 60 can determine whether the vehicle is in the idle state or the shake state.

Next, the assembly sequence and operation of the vibration isolator 10 will be described. When assembling the vibration isolator 10, the block 32 is inserted into the outer cylinder 16 in a liquid such as water or oil. Therefore, the pressure receiving liquid chamber 48, the auxiliary liquid chamber 44, and the restriction passage 54 are uniformly filled with the liquid without air being mixed therein. Next, after squeezing the outer cylinder 16,
The vibration-proof device 10 is completed by crimping both ends of each of them and inserting (or press-fitting) the crimped outer cylinder 16 into the annular portion 14 of the bracket 12 to crimp both ends of the annular portion 14. When the outer cylinder 16 is press-fitted into the annular portion 14, both ends of the annular portion 14 do not have to be caulked.

Next, the operation of this embodiment will be described. When the bracket 12 of the vibration isolator 10 is connected to the vehicle body of a vehicle such as an automobile and the inner cylinder 31 is connected to the engine, the vibration of the engine causes vibration of the inner cylinder 31, the elastic body 34, and the outer cylinder 16.
Also, the vibration is absorbed by the resistance due to the internal friction of the elastic body 34, which is supported by the vehicle body of the automobile through the bracket 12.

When the vehicle travels at 70-80 km / h, for example, shake vibration (less than 15 Hz) may occur. Control means 7
In 0, the vehicle speed sensor 72 and the engine speed sensor 74 determine whether or not a shake vibration is occurring. When the control means 70 determines that the shake vibration is occurring, the control means 70
Switches the 3-port 2-position switching valve 62 to connect the connecting pipe 6
The 0 side (the air chamber 52 side) and the pipe 64 side (the intake manifold hold 68 side) are connected. As a result, the air in the air chamber 52 is sucked toward the intake manifold hold 68 side, and the inside of the air chamber 52 becomes negative pressure, and the diaphragm 24
Is the annular portion 1 of the bracket 12 as shown by the solid line in FIG.
4 Stick to the inner surface.

The inner cylinder 31 is moved to the outer cylinder 1 by the shake vibration input.
When the elastic body 34 is deformed relative to 6 and the elastic body 34 is deformed, the pressure in the pressure receiving liquid chamber 48 changes, and the liquid moves back and forth between the pressure receiving liquid chamber 48 and the sub liquid chamber 44 via the restriction passage 54. At this time, the liquid receives passage resistance in the limiting passage 54 or resonates in the liquid column to obtain a large loss coefficient (tan δ), and the shake vibration is effectively absorbed. Since the thick portion 28 that comes into contact with the opening of the communication hole 56 has high rigidity when the diaphragm 24 comes into close contact with the inner peripheral surface of the annular portion 14,
It does not bulge and deform in the suction direction due to the suction force. Therefore, there is no risk that the thick portion 28 will be marked by the opening of the communication hole 56 or will be scratched.

When the engine is idling or when the vehicle speed is 5 km / h or less, idle vibration (for example, in the case of a 4-cylinder engine, a frequency of 20 to 30 Hz,
Amplitude ± 0.3 mm, frequency 30 for 6 cylinder engine
.About.40 Hz, amplitude ± 0.1 mm) occurs. The control means 7
In 0, the vehicle speed sensor 72 and the engine speed sensor 74 determine whether or not idle vibration is occurring. When the control means 70 determines that the idle vibration is occurring, the control means 70
Switches the three-port two-position switching valve 62 to connect the pipe 60 side (air chamber 52 side) and the atmosphere communication pipe 66 side (atmosphere side) so that the air chamber 52 has the same pressure as the atmosphere. Therefore, the diaphragm 24 is moved by the elastic force of the movable portion 30 as shown in FIG.
As shown by the imaginary line, it can move away from the inner peripheral surface of the annular portion 14. This suppresses an increase in the pressure inside the pressure receiving liquid chamber 48 during idle vibration, that is, suppresses an increase in the dynamic spring constant of the vibration isolator 10 and reliably absorbs idle vibration.

Also, when the engine speed increases and vibration in the muffled sound range (for example, high frequency vibration of frequency 80 Hz or more) occurs, the control means 70 controls the 3-port 2-position switching valve 62. Pipe 60 side (air chamber 52 side)
And the atmosphere communication pipe 66 side (atmosphere side) are communicated with each other, and the diaphragm 24 is movable. As a result, the dynamic spring constant of the vibration isolator 10 is reduced and the vibration in the muffled sound range is absorbed.

Further, in this vibration isolator 10, the elastic body 34
Since the thin rubber layer 22 and the thin rubber layer 22 are in close contact with each other, the liquid is enclosed in the outer cylinder 16 and the sealing portion does not move, so that the reliability of the liquid leakage is high. Furthermore, it is possible to immediately cope with mounting on another vehicle body having a different shape simply by changing the bracket 12.

[Second Embodiment] Anti-vibration device 10 according to the present invention
The second embodiment will be described with reference to FIG. The first
The same components as those in the embodiment are designated by the same reference numerals and the description thereof will be omitted.

In this embodiment, the pipe 58 has a flange portion 58A formed at one end thereof.
An annular small protrusion 58B is formed on the annular portion 14 side of A. This pipe 58 has a flange portion 58A and an annular portion 14A.
It is fixed to the annular portion 14 by pressing against and resistance welding.

[Third Embodiment] Anti-vibration device 10 according to the present invention
A third embodiment will be described with reference to FIG. The first
The same components as those in the embodiment are designated by the same reference numerals and the description thereof will be omitted.

In this embodiment, the pipe 58 is the annular portion 14
Since it is formed by drawing a part of it with a press, it has no joint with the annular portion 14 and has high reliability against air leakage.

[Fourth Embodiment] Anti-vibration device 10 according to the present invention
A fourth embodiment will be described with reference to FIG. The first
The same components as those in the embodiment are designated by the same reference numerals and the description thereof will be omitted.

In this embodiment, a rectangular hole 76 having substantially the same size as the rectangular hole 18 of the outer cylinder 16 is formed in the annular portion 14, and the outer periphery of the annular portion 14 is closed so as to close the rectangular hole 76. An arc plate 78 is fixed to the. Also, the arc plate 7
A hole 80 is formed in the central portion of 8, and the pipe 58 is fixed to the arc plate 80 corresponding to the hole 80.

In this embodiment, since the diaphragm 24 can move to the outer side of the outer cylinder 16 by the thickness dimension of the annular portion 14 compared with the vibration isolator 10 shown in the first embodiment, the vibration of the diaphragm 24 is caused. At this time, even if the pressure in the pressure receiving liquid chamber 48 rises, the diaphragm 24 does not come into contact with the inner peripheral surface of the annular portion 14, so that the vibration of the diaphragm 24 is not hindered and the spring constant is not increased.

[Fifth Embodiment] Anti-vibration device 10 according to the present invention
A fifth embodiment will be described with reference to FIG. The first
The same components as those in the embodiment are designated by the same reference numerals and the description thereof will be omitted.

As shown in FIG. 6, in this embodiment, a plurality of communicating holes 56 are formed over the entire surface of the air chamber 52 in the annular portion 14 of the bracket 12 corresponding to the air chamber 52. Further, these communication holes 56 are provided on the outer periphery of the annular portion 14.
A preliminary air chamber 82 that surrounds the auxiliary air chamber 82 is provided, and the partition pipe 84 that forms the preliminary air chamber 82 is integrally provided with the connecting pipe 58.

In this embodiment, since the air in the air chamber 52 is sucked through the plurality of communication holes 56, the air in the air chamber 52 can be sucked in more reliably.

[Sixth Embodiment] Anti-vibration device 10 according to the present invention
A sixth embodiment will be described with reference to FIG. The first
The same components as those in the embodiment are designated by the same reference numerals and the description thereof will be omitted.

As shown in FIG. 7, in this embodiment, in the thick portion 28 of the diaphragm 24, a fiber layer 86 made of synthetic fiber or the like is embedded in the vicinity of the surface on the annular portion 14 side. For this reason, the surface hardness of the thick portion 28 on the side of the annular portion 14 is higher than that of the thick portion 28 of the first embodiment, and the contact mark at the opening corner portion of the communication hole 56 is further difficult to be formed.

[Seventh Embodiment] Anti-vibration device 10 according to the present invention
A seventh embodiment will be described with reference to FIG. The first
The same components as those in the embodiment are designated by the same reference numerals and the description thereof will be omitted.

As shown in FIG. 8, in this embodiment, a plate 88 made of resin or metal is fixed to the surface of the thick portion 28 of the diaphragm 24 on the annular portion 14 side. In this case, since the plate 88 comes into close contact with the annular portion 14,
There is no fear that the contact mark at the opening corner of the communication hole 56 will be attached to the thick portion 28.

[Eighth Embodiment] Anti-vibration device 10 according to the present invention
The eighth embodiment will be described with reference to FIG. The first
The same components as those in the embodiment are designated by the same reference numerals and the description thereof will be omitted.

As shown in FIG. 9A, in this embodiment,
The thick portion 28 of the diaphragm 24 has a substantially block shape,
As shown in FIG. 9B, a cross groove 90 is formed on the surface of the thick portion 28 on the annular portion 14 side. The center intersecting portion of the cross groove 90 corresponds to the communication hole 56 of the annular portion 14, and even when the thick portion 28 comes into close contact with the annular portion 14,
Air in the vicinity of the movable portion 30 of the air chamber 52 can be reliably sucked. Further, the thick portion 28 has a role of a stopper that restricts the inner cylinder 31 from moving toward the pressure receiving liquid chamber 48 more than a predetermined amount.

[Ninth Embodiment] Anti-vibration device 10 according to the present invention
A ninth embodiment will be described with reference to FIG. The same components as those in the first embodiment are designated by the same reference numerals and the description thereof will be omitted.

As shown in FIG. 10, in this embodiment, a stopper plate 92 is arranged in the pressure receiving liquid chamber 48 with a predetermined distance from the diaphragm 24. This stopper plate 92 has an elastic body 34 and a thin rubber layer 2 at the edge.
It is sandwiched and fixed between the two. Further, the stopper plate 92 has a plurality of holes 94 for liquid circulation.

In this embodiment, even if the pressure fluctuation in the pressure receiving liquid chamber 48 exceeds a predetermined value, the diaphragm 24 comes into contact with the stopper plate 92 and its movement is restricted, so that the movable portion 30 of the diaphragm 24 has a predetermined value. The tensile stress described above does not act, and the durability of the diaphragm 24 is improved.

[Tenth Embodiment] Anti-vibration device 1 according to the present invention
A tenth embodiment of No. 0 will be described with reference to FIG. The same components as those in the first embodiment are designated by the same reference numerals and the description thereof will be omitted.

As shown in FIG. 11, in the vibration isolator 10 of this embodiment, a stopper plate 92 is provided in the pressure receiving liquid chamber 48 as in the ninth embodiment. The first
In the zero embodiment, the stopper plate 92 is formed in an arc shape along the thick portion 28 of the diaphragm 24,
A large diameter hole 96 is formed in the center.

In this embodiment as well, as in the ninth embodiment, even if the pressure fluctuation in the pressure receiving liquid chamber 48 exceeds a predetermined value, the diaphragm 24 comes into contact with the stopper plate 92 and its movement is restricted. A tensile stress of a predetermined amount or more does not act on the movable portion 30 of 24, and the durability of the diaphragm 24 is improved.

[Eleventh Embodiment] A vibration isolation device 1 according to the present invention
An eleventh embodiment of No. 0 will be described with reference to FIG. The same components as those in the first embodiment are designated by the same reference numerals and the description thereof will be omitted.

As shown in FIG. 12, in this embodiment, a cup-shaped stopper 98 having an opening on the diaphragm 24 side is provided in the pressure receiving liquid chamber 48. A plurality of holes 100 are formed on the outer periphery of the stopper 98, and a flange portion 102 is formed on the peripheral edge portion. The outer periphery of the flange portion 102 is sandwiched and fixed between the elastic body 34 and the thin rubber layer 22. Further, the cross-sectional shape of the flange portion 102 follows the shape of the movable portion 30 of the diaphragm 24, and has a role of limiting the moving amount of the diaphragm 24 when moving to the pressure receiving liquid chamber 48 side. Also, the stopper 98
The bottom portion is separated from the bottom surface of the recess 46 by a predetermined dimension, and has a role of limiting the amount of movement of the inner cylinder 31 toward the pressure receiving liquid chamber 48 side. Therefore, the elastic body 34 and the diaphragm 2
No excessive stress acts on 4, and the durability is improved.

13 and 14 are graphs showing the vibration-damping characteristics of the experimental example of the vibration-damping device 10 according to the present invention.

The vibration isolator 10 having the characteristics shown in FIG. 13 is tuned so that a large loss coefficient (tan δ) is obtained in the shake vibration region (frequency of about 8 to 12 Hz) when the diaphragm 24 is in close contact with the annular portion 14. ing.
Therefore, by separating the diaphragm 24 from the annular portion 14, the idle vibration range (frequency of 20 to 30 Hz)
It is possible to reduce the dynamic spring constant in the vicinity) and in the muffled sound range (frequency of 100 Hz or more).

On the other hand, the vibration isolation device 10 having the characteristics shown in FIG.
Is the size (length and cross-sectional area) of the restriction passage 54 and the pressure receiving liquid chamber so that the dynamic spring constant decreases in the idle vibration range (frequency near 20 to 30 Hz) when the diaphragm 24 is in close contact with the annular portion 14. The expansion and contraction power of 48 is tuned. Therefore, when the diaphragm 24 is separated from the annular portion 14, the loss factor (tan
The peak of δ) moves to the low frequency side, that is, moves to the shake vibration region (frequency near 10 Hz), and the dynamic spring constant decreases in the shake vibration region. Further, when the diaphragm 24 is separated from the annular portion 14, the dynamic spring constant is reduced even in the muffled sound range (frequency of 80 Hz or higher).

As is clear from the graph of the above experimental example, the vibration isolator 10 of the present invention has excellent vibration isolating performance capable of reliably absorbing vibrations in different frequency ranges.

The frequencies of the idle vibration range, the shake vibration range and the muffled sound range are not limited to the frequency ranges described in the above embodiments. Further, it goes without saying that the vibrations to be absorbed may be vibrations other than the idle vibration range, the shake vibration range and the muffled sound range.

[0058]

Since the vibration isolator according to the present invention has the above-mentioned structure, it has an excellent effect that it can surely absorb the vibration of the desired frequency.

[Brief description of drawings]

FIG. 1 is an exploded perspective view showing a vibration damping device according to a first embodiment of the present invention.

FIG. 2 is a partial cross-sectional view of a vibration isolator according to the first exemplary embodiment of the present invention.

FIG. 3 is a partial cross-sectional view of a vibration control device according to a second embodiment of the present invention.

FIG. 4 is a partial cross-sectional view of a vibration damping device according to a third embodiment of the present invention.

FIG. 5 is a partial cross-sectional view of a vibration damping device according to a fourth embodiment of the present invention.

FIG. 6 is a partial cross-sectional view of a vibration control device according to a fifth embodiment of the present invention.

FIG. 7 is a partial cross-sectional view of a vibration control device according to a sixth embodiment of the present invention.

FIG. 8 is a partial cross-sectional view of a vibration control device according to a seventh embodiment of the present invention.

FIG. 9 is a partial cross-sectional view of a vibration damping device according to an eighth embodiment of the present invention.

FIG. 10 is a partial cross-sectional view of a vibration control device according to a ninth embodiment of the present invention.

FIG. 11 is a partial cross-sectional view of a vibration control device according to a tenth embodiment of the present invention.

FIG. 12 is a partial cross-sectional view of a vibration control device according to an eleventh embodiment of the present invention.

FIG. 13 is a graph showing vibration damping characteristics of the vibration damping device according to the present invention.

FIG. 14 is a graph showing vibration damping characteristics of the vibration damping device according to the present invention.

[Explanation of symbols]

 10 Vibration Isolator 12 Blacket (Mounting Member) 16 Outer Cylinder 24 Diaphragm (Second Elastic Membrane) 26 Diaphragm (First Elastic Membrane) 31 Inner Cylinder 34 Elastic Body 44 Sub Liquid Chamber 48 Pressure Received Liquid Chamber 52 Air Chamber 54 Restriction Passage 56 Communication hole 68 Intake manifold (negative pressure means)

Claims (1)

Claim: What is claimed is: 1. A mounting member that is connected to one of a vibration generating portion or a vibration receiving portion and has an insertion portion, an outer cylinder inserted and arranged in the insertion portion, and a vibration generating portion or a vibration receiving portion. An inner cylinder connected to the other of the inner cylinder, an elastic body that is provided between the inner cylinder and the outer cylinder and deforms when vibration occurs, and the elastic body provided in the outer cylinder expands and contracts as at least a part of a partition wall. A possible pressure receiving liquid chamber, a sub liquid chamber provided in the outer cylinder and separated from the pressure receiving liquid chamber, and a first sub liquid chamber provided in the outer cylinder and forming a part of a partition wall of the sub liquid chamber. An elastic film, a restriction passage provided in the outer cylinder for connecting the pressure receiving liquid chamber and the sub liquid chamber, a part of a partition wall of the pressure receiving liquid chamber provided in the outer cylinder, and the mounting member. And an air chamber between the mounting member and the mounting member side surface shape along the inner peripheral surface of the mounting member And a central part of the second elastic film having a rigidity higher than that of the outer peripheral part, and a second elastic film provided on the mounting member and arranged at a position facing the central part of the second elastic film, and one of And a communication hole connected to the air chamber and the other of which is connected to a negative pressure means for making the air chamber have a negative pressure.