JP2001003978A - Vibration isolating apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce vibrations over a wide range of frequencies without increasing manufacturing costs. SOLUTION: An intermediate cylinder 22 and an intermediate block 24 are arranged inside an outer cylinder metal fitting 16, and a space partitioned by the intermediate block 24 and an elastic body 28 constitutes a main liquid chamber 30. A shake orifice 64 and an idle orifice 60 communicate the main liquid chamber 30 with a first auxiliary liquid chamber 32. An orifice 62 for confirming communicates the main liquid chamber 30 with a second auxiliary liquid chamber 96 and a rotor 36 opens and closes the idle orifice 60 and the orifice 62 for confirming. In this case, a thick-walled high-rigidity part 20C is provided in such a way as to be sandwiched between a pair of thin-walled low-rigidity parts 20B, 20D provided in a first diaphragm 20 along the flow direction F of a liquid which flows into and out of the first auxiliary liquid chamber 32.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vibration isolator for preventing transmission of vibration from a member that generates vibration, and is applicable to, for example, a case where transmission of vibration from an engine mounted on a vehicle is prevented. Things.

[0002]

2. Description of the Related Art For example, an anti-vibration device as an engine mount is disposed between an engine of a vehicle serving as a vibration generating portion and a vehicle body serving as a vibration receiving portion. There is known a structure that absorbs vibration and prevents vibration from being transmitted to the vehicle body. That is, as an example of the vibration isolator, not only the inner cylinder is arranged inside the outer cylinder formed in a cylindrical shape, but also the main liquid chamber and the sub liquid chamber are provided inside the outer cylinder, and the orifice is used. There is a bush type of structure in which these liquid chambers communicate with each other through a restriction passage. When the mounted engine operates and generates vibration, the vibration is absorbed or attenuated as a low dynamic spring due to the liquid column resonance of the liquid in the restricted passage connecting these liquid chambers. Thus, the transmission of vibration is prevented.

FIGS. 12 and 1 show an example of this vibration isolator.
There is a structure shown in FIG. 3, and a conventional vibration isolator will be specifically described below based on these drawings. That is, there is a main liquid chamber 118 and a sub liquid chamber 120 which communicates with the main liquid chamber 118 through an orifice 122 which is a restriction passage inside the outer cylinder 112 which is an outer frame of the vibration isolator. Room 12
The diaphragm 1 in which a part of the partition wall of rubber 0 is an elastic film made of rubber
24 comprises.

[0004] The elastic body 1 accompanying the displacement of the inner cylinder 114 is provided.
Due to the expansion and contraction of the main liquid chamber 118 due to the deformation of the liquid crystal 16, the liquid is
The diaphragm 124 provided on the sub liquid chamber 120 side is entirely uniform in order to more effectively generate liquid column resonance and improve the vibration isolating performance of the vibration isolator. It is designed to expand and contract, and with this,
The center of the diaphragm 124 is most easily moved.

[0005]

On the other hand, the engine speed varies widely with changes in vehicle conditions, and the vibration frequency becomes wide with a wide range of operating conditions of the engine. For this reason, in order to increase the resonance point of the liquid column resonance in order to improve the vibration isolation characteristics even for vibrations of a wide range of frequencies, it is necessary to further provide not only the orifice but also the auxiliary liquid chamber and the diaphragm. However, the structure in which the auxiliary liquid chamber, the diaphragm, and the like are simply incorporated into the vibration isolator has the disadvantage that the number of components increases, the number of steps for assembling the increased components increases, and the manufacturing cost of the vibration isolator increases.

The present invention has been made in view of the above circumstances, and has as its object to provide a vibration damping device capable of reducing vibrations in a wide range of frequencies without increasing manufacturing costs.

[0007]

According to a first aspect of the present invention, there is provided a vibration isolator which is connected to one of a vibration generator and a vibration receiver, and connected to the other of the vibration generator and the vibration receiver. A second mounting member, an elastic body disposed between the mounting members and elastically deformable, and a main liquid chamber in which a liquid is sealed with the elastic body as a part of the partition wall and the inner volume is changed by deformation of the elastic body. A sub-liquid chamber which is communicated with the main liquid chamber via the passage and in which the liquid is sealed, and which has a pair of low-rigid portions along the flow direction of the liquid flowing into and out of the sub-liquid chamber from the passage; A diaphragm that varies the rigidity with a high-rigidity portion interposed therebetween and forms at least a part of the partition wall of the auxiliary liquid chamber so as to be elastically deformable.

The operation of the vibration isolator according to the first aspect will be described below. When vibration is transmitted from the vibration generating unit connected to either the first mounting member or the second mounting member, the elastic body is deformed and the vibration is attenuated by the elastic body. Further, as the internal volume of the main liquid chamber changes due to the deformation of the elastic body, the liquid actively flows to the sub liquid chamber side through the passage. As a result, a pressure change occurs in the liquid in the passage, and the diaphragm that deforms at least a part of the partition wall of the sub liquid chamber so as to be elastically deformable is deformed.

That is, when the vibration is transmitted from the vibration generating section, not only the deformation of the elastic body but also the liquid in the passage connecting between the main liquid chamber and the sub liquid chamber causes the liquid column resonance and the dynamic spring constant. Is reduced, the vibration is absorbed, and it becomes difficult for the vibration to be transmitted to the vibration receiving portion connected to either the second mounting member or the first mounting member. In addition, the rigidity of the diaphragm is varied by sandwiching a high rigidity portion between a pair of low rigidity portions provided on the diaphragm along the flow direction of the liquid flowing into and out of the sub liquid chamber from the passage. Among these, the pair of low rigid portions having low rigidity can be positively elastically deformed.

Therefore, as the liquid flows out of the passage into the sub-liquid chamber, the pair of low-rigid portions located across the high-rigid portion are positively elastically deformed. As a result, the liquid inside the high-rigidity portion resonates with the liquid column, so that the pair of low-rigidity portions individually function as separate diaphragms. For this reason, without increasing the number of parts and the assembling process, the passage serving as the orifice, the auxiliary liquid chamber, and the diaphragm were substantially added one by one, and as a result,
Vibration at a wide range of frequencies can be reduced without increasing the manufacturing cost of the vibration isolator.

The operation of the vibration isolator according to claim 2 will be described below. The present invention operates in the same manner as the first embodiment. Further, since the rigidity of the diaphragm is varied by changing the thickness of the diaphragm along the flow direction of the liquid, a low-rigid portion and a high-rigid portion having different rigidities are easily provided on the diaphragm with a simple configuration. This does not complicate the manufacture of the diaphragm and does not increase the manufacturing cost of the vibration isolator.

The operation of the vibration isolator according to claim 3 will be described below. In the present invention, the same operation as in the first embodiment is performed, but the center part of the diaphragm along the flow direction of the liquid is formed in a linear shape, and both ends along the flow direction of the liquid with respect to the center part. Since the rigidity of the diaphragm is varied by making the sides slack, the high-rigidity portion is formed by the linear portion and the low-rigidity portion is formed by the slackened portion. Therefore, similarly to the second aspect, the low-rigidity portion and the high-rigidity portion having mutually different rigidities can be easily provided on the diaphragm with a simple configuration, and accordingly, the production of the diaphragm is not complicated, This does not increase the manufacturing cost of the vibration isolator.

According to a fourth aspect of the present invention, there is provided an anti-vibration device having an inner cylinder connected to one of a vibration generator and a vibration receiver, and an inner cylinder connected to the other of the vibration generator and the vibration receiver and surrounding the inner cylinder. An elastic body which is disposed between the inner cylinder and the outer cylinder and which can be elastically deformed, and a liquid is sealed with the elastic body as a part of the partition wall and the inner volume is increased by the deformation of the elastic body. A main liquid chamber that changes, a sub liquid chamber that communicates with the main liquid chamber via a passage and is filled with liquid, and a pair of low-rigid portions along a flow direction of the liquid that flows into and out of the sub liquid chamber from the passage. And having the rigidity fluctuate in the form of sandwiching the high rigidity portion between them, and
A diaphragm for forming at least a part of the partition wall of the sub liquid chamber so as to be elastically deformable.

The operation of the vibration isolator according to claim 4 will be described below. The present invention has the same effect as the first embodiment. However, in the present invention, the first mounting member is replaced by an inner cylinder, and the second mounting member is replaced by an outer cylinder formed in a cylindrical shape. When the vibration is transmitted to one of the outer cylinders, the vibration is less likely to be transmitted to the vibration receiving unit to which the outer cylinder or the inner cylinder is connected.

Further, similarly to the first aspect, the high rigidity portion is sandwiched between a pair of low rigidity portions provided on the diaphragm along the flow direction of the liquid flowing into and out of the sub liquid chamber from the passage. Since the stiffness of the diaphragm was changed, the passage, the auxiliary liquid chamber, and the diaphragm serving as the orifice were substantially added one by one without increasing the number of parts and the assembling process as in claim 1. In addition, vibrations in a wide range of frequencies can be reduced without increasing the manufacturing cost of the vibration isolator.

The operation of the vibration damping device according to the fifth and sixth aspects will be described below. Since claim 5 operates in the same manner as in claim 2 and claim 6 operates in the same manner as in claim 3, the manufacturing of the diaphragm is also not complicated by these claims 5 and 6, so that the vibration isolator is not required. It has become possible to reduce vibrations in a wide range of frequencies without increasing the manufacturing cost of the device.

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment of a vibration isolator according to the present invention is shown in FIGS. 1 to 8, and this embodiment will be described with reference to these drawings. As shown in FIGS. 1 to 4, the so-called bush type vibration damping device 10 is provided with a bracket 12 having a pair of legs 12 </ b> A at a lower portion in a ring shape for connection to a vehicle body (not shown). Bracket 1
Inside 2, a cylindrical outer tube fitting 16 is fitted and arranged.

As shown in FIG. 5, a pair of arc members 14A each formed in an arc shape and a pair of connecting members 14B respectively connecting both ends of the pair of arc members are formed.
A metal supporting frame 14 is formed in a square frame shape, and an outer peripheral edge 20A constituting the outer peripheral portion of the first diaphragm 20 which is a thin elastic film made of rubber is vulcanized on the rectangular frame-shaped supporting frame 14. Glued. The first diaphragm 20 is located closer to the upper side in FIGS. 1 and 2 on the inner peripheral surface side of the outer cylinder fitting 16 by installing the support frame 14 at a position closer to the upper side in the outer cylinder fitting 16. Be placed. In addition, as shown in FIGS.
The central portion of the diaphragm 20 is made thick to be a high rigidity high rigidity portion 20C, and on both sides of the high rigidity portion 20C,
Low rigidity portions 20B and 20D which are thinner than this and have lower rigidity than the high rigidity portion 20C are formed, respectively.

On the other hand, an intermediate tube 22 and an intermediate block 24 are inserted into the outer tube fitting 16.
And the intermediate block 24 constitutes a partition member. The intermediate block 24 is formed in a substantially semicircular block shape when viewed from the axial direction of the outer cylindrical member 16. As shown in FIG. 1, the outer peripheral surface of the intermediate block 24 is formed on the inner peripheral surface of the outer cylindrical member 16. Closely adhered. As shown in FIG. 2, flange portions 22 </ b> A are formed at both ends in the axial direction of the intermediate cylinder 22. An intermediate block 24 is provided between the pair of flange portions 22 </ b> A and closer to the lower side of the intermediate cylinder 22. It will be inserted. The outer peripheral surfaces of the pair of flange portions 22 </ b> A are in close contact with the inner peripheral surface of the outer cylinder fitting 16.

Along with this, the support frame 14 is fitted between the pair of flange portions 22A and closer to the upper side of the intermediate cylinder 22, so that the outer peripheral edge 20 of the first diaphragm 20 is
A is fixed while being supported between the inner peripheral surface side near the upper part of the outer cylinder fitting 16 and the intermediate cylinder 22.

As shown in FIG. 1 and FIG. 2, the space between the first diaphragm 20 and the outer cylinder 16 is the first space.
The first diaphragm 2 shown in FIG. 1 is an air chamber 31 which is a central portion in the axial direction of the outer tube fitting 16 shown in FIG.
A through hole 18 is provided in a portion of the outer cylinder 16 eccentric along the circumferential direction of the outer cylinder 16 from a position facing the center of the outer cylinder 0. A hole 12 </ b> B is provided through the bracket 12 at a position overlapping the through hole 18.

For this reason, the first air chamber 31 is
Is communicated with the outside through the through hole 18 and the hole 12B of the bracket 12, so that the air in the first air chamber 31 can flow to and from the outside through the through hole 18 and the hole 12B. In addition, as shown in FIG. 1 and FIG.
8, a rivet hole 82 for a rivet 78 for sealing the inside of the vibration isolator 10 and a hole 84 for receiving a rotating shaft 71 of a motor 70 to be described later are formed in the outer metal shell 16. It is provided through.

As shown in FIGS. 1 and 2, the portion of the intermediate cylinder 22 facing the flat portion 24B serving as the upper surface of the intermediate block 24 is notched and has a hollow interior.
An inner cylinder fitting 26 connected to an engine (not shown) penetrates the inside of the cavity. This inner cylinder fitting 26 is used for the outer cylinder fitting 16.
And an elastic body 28 formed of a rubber material or the like is stretched between the intermediate tube 22 and the intermediate tube 22. As a result, the inner cylindrical member 26 can be moved relative to the outer cylindrical member 16. That is, the inner cylindrical metal fitting 26 connected to the engine as the vibration generating part is the first mounting member, and the outer cylindrical metal fitting 1 connected to the vehicle body as the vibration receiving part via the bracket 12.
6 is a second mounting member.

Further, the elastic body 28 also extends on the outer peripheral surface between the flange portions 22A of the intermediate cylinder 22, and protrudes from both ends of the intermediate block 24 and is formed on the inner peripheral side of the arc-shaped portion. A part of the elastic body 28 is in close contact with the inner circumferential arc surface 24A. A notch 28A is formed in the middle of the elastic body 28 and below the inner cylindrical fitting 26 so as to depress the lower surface of the elastic body 28. The space between them is the main liquid chamber 30.

On the other hand, a pair of flange portions 22 of the intermediate cylinder 22
A first sub-liquid chamber 32 surrounded by the intermediate cylinder 22 and the first diaphragm 20 is formed between A, and the first diaphragm 20 elastically deforms a part of the partition wall of the first sub-liquid chamber 32. It is configured to be possible. As shown in FIG. 7, a groove 46 is formed in a U-shape on the outer peripheral surface of the intermediate block 24. One end of the groove 46 is connected to the intermediate block 24.
In FIG. 1, the first sub liquid chamber 32 is opened at the right end.
It is connected to. The other end of the groove 46 communicates with the main liquid chamber 30 via a through hole 48 formed through the middle block 24. The groove 46 and the through hole 48 form a shake orifice 64 as a restriction passage for absorbing shake vibration.

Further, the plane portion 24B of the intermediate block 24
A circular hole 34 is formed on the side of the intermediate block 2.
A circular through-hole 35 penetrating the outer peripheral surface of 4 is formed coaxially with the circular hole 34. The counterbore portion 3 is coaxially formed with the circular through hole 35 on the outer cylinder fitting 16 side of the intermediate block 24.
9 is provided, and an O-ring 41 for sealing is fitted outside the counterbore portion 39.

The circular hole 34 and the circular through hole 35 have:
A rotor 36 as a valve is rotatably inserted.
The main liquid chamber 30 side of the rotor 36 has a cylindrical cylindrical portion 36A.
A thin shaft portion 36B as a rotation axis is provided coaxially with the cylindrical portion 36A at a portion opposite to the cylindrical portion 36A. Further, a lid plate 40 also serving as a washer is fixed to the plane portion 24B side of the intermediate block 24 to prevent the rotor 36 from coming off.

A pair of O-rings 44 are fitted around the outer periphery of the thin shaft portion 36B. Therefore, this O
The liquid does not leak out of the intermediate block 24 through the circular through hole 35 by the ring 44. Further, a through hole 38 is formed in the cylindrical portion 36A of the rotor 36 to communicate the inside and the outside of the cylindrical portion 36A. On the other hand, one end side of the intermediate block 24 is connected to the circular hole 34 and FIG.
The passage 56 extends in a direction perpendicular to the plane of FIG.
Are formed. That is, one end of the passage 56 is opened at the inner periphery of the circular hole 34.

As shown in FIG. 6 and FIG.
Is connected to one end of a passage 58 which is a groove formed in the outer periphery of the intermediate block 24 along the circumferential direction. The other end of the passage 58 is connected to the first auxiliary liquid chamber 32. . Accordingly, when the rotor 36 rotates and the through hole 38 faces the passage 56 as shown in FIG. 1, the main liquid chamber 30 and the first sub liquid chamber 32 are communicated by the passages 56 and 58. Will be. In other words, the idle orifice 6 which communicates the main liquid chamber 30 and the first sub liquid chamber 32 by these passages 56 and 58 and serves as a restriction passage for absorbing idle vibration.
0 will be configured.

As shown in FIGS. 1 and 3, a portion corresponding to the first auxiliary liquid chamber 32 facing the ends of the shake orifice 64 and the idle orifice 60 is provided with the pair of low rigid portions 20B described above. One of the low rigidity portions 2 of 20D
0B is located, a high-rigidity portion 20C is disposed to the left of the one low-rigidity portion 20B, and another low-rigidity portion 20D is disposed to the left of the high-rigidity portion 20C. . That is, the pair of low-rigidity portions 20B, 2B, 2C, 2D, 2D
By changing the thickness of the first diaphragm 20 so as to have 0D and sandwich the high rigidity portion 20C between them,
The structure in which the rigidity of the first diaphragm 20 is changed is adopted.

On the other hand, as shown in FIGS. 1 and 3, the intermediate block 24 is further provided with a recessed hole 92 extending in the radial direction of the circular hole 34 and in the opposite direction to the passage 56.
Although much shorter than 6, it is formed. A second sub-liquid chamber 96 which is an arc-shaped space is formed in a portion of the intermediate block 24 corresponding to the opening end of the hole 92, and the end of the hole 92 is formed in a second shape. The second sub liquid chamber 96 is open. Accordingly, the rotor 36 rotates, and FIG.
When the through hole 38 is opposed to the hole 92 for stagnation as shown in FIG. 7, the communication between the main liquid chamber 30 and the second sub liquid chamber 96 is established. In other words, the hollow hole 92 formed much shorter than the passage 56 so as to absorb the high frequency vibration.
The main orifice orifice 62 communicates with the main liquid chamber 30 and the second sub liquid chamber 96 and serves as a restriction passage for absorbing a medium-to-low speed muffled sound that is higher in frequency than idle vibration.
Is configured.

A thin rubber-made second diaphragm 94 is provided on the outer peripheral side of the intermediate block 24 with respect to the second sub liquid chamber 96, and the outer peripheral portion of the second diaphragm 94 is formed between the outer tube fitting 16 and the intermediate block 24. The second diaphragm 94 is sandwiched between them, and serves as an elastically deformable partition wall of the second sub liquid chamber 96. Therefore, the space between the second diaphragm 94 and the inner peripheral surface side of the outer cylinder fitting 16 is
And a second air chamber 98 in which a gas is sealed. The second air chamber 98 enables the deformation of the second diaphragm 94.

Accordingly, the second diaphragm 94 constitutes a part of the partition wall of the second auxiliary liquid chamber 96. As shown in FIG. 1, the area of the second diaphragm 94 is equal to the first auxiliary liquid chamber 96. The first diaphragm 20 which constitutes a part of the partition wall 32
And the thickness of the second diaphragm 94 is substantially equal to that of the first diaphragm 20, so that the second diaphragm 94 has a higher rigidity than the first diaphragm 20. The main liquid chamber 30, the first sub liquid chamber 32, and the second sub liquid chamber 96 are sealed so as to be filled with a liquid such as ethylene glycol.

On the other hand, a motor 70 as an actuator is provided outside the bracket 12. The tip of the rotating shaft 71 of the motor 70 is
6B. The motor 70 is provided with a flange 70A.
0A is formed in an arc shape along the outer diameter of the bracket 12. Therefore, a screw (not shown) inserted through the flange portion 70 </ b> A is screwed into a screw portion (not shown) provided on the bracket 12, so that the motor 70 is fixed to the bracket 12.

With the structure described above, the rotor 36 is rotated by the motor 70, and as shown in FIG.
When the through hole 38 of 6A opens the idle orifice 60, the main liquid chamber 30 and the first
Is communicated with the sub liquid chamber 32. When the rotor 36 is rotated 180 ° by the motor 70 from this position, and the through hole 38 of the cylindrical portion 36A opens the orifice 62 as shown in FIG. 3, the main liquid chamber is opened via the orifice 62. The 30 and the second sub liquid chamber 96 are communicated.

When the rotor 36 is further rotated by 180 ° from this position by the motor 70, the idle orifice 60 is opened again as described above.
Thereafter, the orifices are sequentially opened as described above. Accordingly, the orifices 60 and 62 are switched by opening and closing the orifices 60 and 62 so that the idle vibration as the vibration in the low frequency range and the vibration during traveling as the vibration in the high frequency range can be reduced. .

As described above, the arrangement in which the rotor 36 communicates between the main liquid chamber 30 and the first sub liquid chamber 32 through the idle orifice 60 as shown in FIG. 1 and the confinement as shown in FIG. The rotor 36 is rotated by the motor 70 so as to selectively adopt an arrangement for communicating between the main liquid chamber 30 and the second sub liquid chamber 96 via the orifice 62.
The motor 70 is connected to a controller 72 as control means, and its rotation is controlled by the controller 72. The controller 72 is operated by the vehicle power supply, receives detection signals from at least the vehicle speed sensor 74 and the engine speed detection sensor 76, detects the vehicle speed and the engine speed, and can determine whether idle vibration or shake vibration occurs. It has become.

Next, the operation of the present embodiment will be described. When the engine mounted on the vibration isolator 10 connected to the inner cylinder fitting 26 operates, the vibration of the engine is transmitted to the elastic body 28 via the inner cylinder fitting 26. The elastic body 28 acts as a vibration absorbing main body, and can absorb vibration by a vibration damping function based on internal friction of the elastic body 28. Further, the elastic body 2
The liquids in the main liquid chamber 30 and the first sub liquid chamber 32, whose internal volumes change with the deformation of the first and second diaphragms 20, 8 and the like, flow mutually via the shake orifice 64 or the idle orifice 60, and the like. , The main liquid chamber 3 whose internal volume changes with the deformation of the elastic body 28 and the second diaphragm 94
The liquids in the zero and second sub liquid chambers 96 flow mutually via the orifice 62 for spillover, and a vibration damping effect is provided by a damping action based on the viscous resistance of the liquid flow generated in these orifice spaces and liquid column resonance. Can be improved.

In addition to the normally open shake orifice 64, an idle orifice 60 and a muffled orifice 62 are provided, and a rotor 36 for switching the passage between the idle orifice 60 and the muffled orifice 62 is provided. As a result, it operates as follows.

For example, when the engine is idling or the vehicle speed is 5 km / h or less, the idle vibration (2
5Hz). The controller 72 is a vehicle speed sensor 7
4. It is determined by the engine speed sensor 76 whether idle vibration has occurred. When the controller 72 determines that idle vibration has occurred, the controller 72 rotates the motor 70 to rotate the rotor 36 as shown in FIG.
Are arranged so as to correspond to the idle orifices 60 and do not correspond to the orifices 62 for shunting.

As a result, the orifice 62 is closed, and the liquid moves between the main liquid chamber 30 and the first sub liquid chamber 32 through the idle orifice 60. Due to column resonance, the dynamic spring constant decreases, and idle vibration is absorbed.

On the other hand, when the vehicle runs at a high speed of, for example, 70 to 80 km / h or more, shake vibration (about 10 Hz) occurs. The controller 72 determines whether or not a shake vibration has occurred based on a vehicle speed sensor 74 and an engine speed detection sensor 76. When the controller 72 determines that the shake vibration is occurring, the controller 72 operates the motor 70 to rotate the rotor 36, as shown in FIG. 3, and associates the through hole 38 with the retraction orifice 62 and the idle orifice 60. And an arrangement that does not correspond to

As a result, the idle orifice 60 is closed, the normally open shake orifice 64 communicates the main liquid chamber 30 with the first sub liquid chamber 32, and the confined orifice 62 connects the main liquid chamber 30 with the first liquid chamber 30. Second sub liquid chamber 96
And communicate with. As a result, a pressure change based on the engine vibration generated in the main liquid chamber 30 is transmitted to the liquid in the shake orifice 64 and the orifice 62, and the shake of the liquid is absorbed by the resistance of the liquid. Further, for a low-speed muffled sound (about 80 Hz), which is a high-frequency and small-amplitude vibration that may be generated together with the shake vibration, the liquid column resonates in the short orifice 62 and the dynamic spring constant decreases. Then, this muffled sound is absorbed.

As described above, the main liquid chamber 30 and the sub liquid chambers 32, 96
The two orifices 60, 62, which are respectively opposed to one ends of the two orifices 60, 62 which can communicate with each other to reduce the vibration, are rotated by the motor 70, and the two orifices 60, 62 are rotated. 62 can be selectively opened and closed, and accordingly, vibrations at two different frequencies can be reduced. As a result, the vibration is appropriately absorbed at any vibration frequency, and a wide range of vibration can be reduced.

Also, as shown in FIGS. 1 and 3, the first orifice 60 and the shake orifice 64
The thick high-rigidity portion 20C is sandwiched between a pair of thin low-rigidity portions 20B and 20D provided in the first diaphragm 20 along the flow direction F of the liquid flowing into and out of the sub liquid chamber 32. Since the rigidity of the first diaphragm 20 is changed, the pair of thin, low-rigidity portions 20B and 20D of the first diaphragm 20 can be positively elastically deformed.

Therefore, the high-rigidity portion 20C is unlikely to be deformed as the liquid flows out of the orifices 60 and 64 into the first auxiliary liquid chamber 32, whereas the high-rigidity portion 20C in FIGS. Low rigidity part 20B and high rigidity part 2 on the right of 20C
The low-rigidity portion 20D on the left of 0C is positively elastically deformed as indicated by the two-dot chain line.
Have the same function as the passage. As the liquid inside the high-rigidity portion 20C resonates with the liquid column, the pair of low-rigidity portions 20B and 20D individually function as separate diaphragms.

That is, FIG. 1 and FIG.
, The portion of the first sub liquid chamber 32 facing the low rigidity part 20B on the right side is a small auxiliary liquid chamber on the front side, and the low rigidity part 20B itself independently functions as a diaphragm. Further, the first sub liquid chamber 3 facing the high rigidity portion 20C
The orifice 2 is an orifice that resonates with the liquid column inside, and the low rigid portion 20 adjacent to the high rigid portion 20C in FIGS.
The portion of the first sub-liquid chamber 32 facing D is a small sub-liquid chamber on the back side, and the low-rigidity portion 20D itself independently functions as a diaphragm.

Accordingly, without increasing the number of parts and the assembling process, a passage serving as an orifice, a sub-liquid chamber and a diaphragm are substantially added one by one.
As a result, it is possible to reduce vibrations in a wider range of frequencies without increasing the manufacturing cost of the vibration isolator 10. Specifically, a pair of low rigidity parts 20B, 20D
Function as individual diaphragms, the range of frequencies at which the dynamic spring is reduced is widened. For this reason, as shown in FIG. 8 showing the relationship between the dynamic spring constant and the vibration frequency, the dynamic spring constant K represented by the solid line of the vibration isolator 10 according to the present embodiment is different from that of the conventional vibration isolator represented by the dotted line. The dynamic spring constant K is lower up to a higher frequency range.

Further, in this embodiment, the rigidity of the first diaphragm 20 is varied by changing the thickness along the flow direction F of the liquid.
0B, 20D and the high-rigidity portion 20C with the first diaphragm 2
0 can be easily provided with a simple configuration, and accordingly, the manufacture of the first diaphragm 20 does not become complicated.

Next, a second embodiment of the vibration isolator according to the present invention is shown in FIGS. 9 to 11, and this embodiment will be described with reference to FIGS. The same members as those described in the first embodiment are denoted by the same reference numerals, and redundant description will be omitted. In the present embodiment, as shown in FIGS. 9 and 10, not only the auxiliary liquid chamber is made larger than the conventional vibration isolator, but also the central portion of the diaphragm along the flow direction F of the liquid has no slack. The high-rigidity portion 20C has a linear shape, and the low-rigidity portions 20B and 20B have a shape in which both ends along the liquid flowing direction F are slackened with respect to the center.
As D, the rigidity of the first diaphragm 20 was varied.

As a result, as in the first embodiment, it becomes possible to reduce vibrations in a wider range of frequencies without increasing the manufacturing cost of the vibration isolator 10. Specifically, as in the first embodiment, the range of the frequency at which the dynamic spring is reduced is widened, and as shown in FIG. 11, the dynamic vibration represented by the solid line of the vibration damping device 10 according to the present embodiment. Spring constant K
Is lower than the dynamic spring constant K of the conventional vibration isolator represented by the dotted line to a higher frequency side.

Further, by adopting such a structure, similarly to the first embodiment, the first diaphragm 20 has a simple structure in which the low rigidity portions 20B and 20D and the high rigidity portion 20C having different rigidities are provided. Therefore, the manufacture of the first diaphragm 20 is not complicated.

According to the above embodiment, the present invention not only makes the auxiliary liquid chamber larger than the conventional vibration isolator, but also
With the first diaphragm 20, it is possible to obtain a vibration isolation characteristic having two peaks similar to that of an engine mount having a double orifice structure. The structure for providing a difference in the rigidity of the diaphragm is the same as that of the first embodiment.
In addition to the structure in which the thickness of the diaphragm 20 is changed or the shape of the first diaphragm 20 is changed as in the second embodiment, the width dimension of the first diaphragm 20 in a direction perpendicular to the flow direction F of the liquid May be narrowed at the center and widened at both ends.

Further, in the above embodiment, the outer cylinder fitting 16 is attached to the vehicle body, and the inner cylinder fitting 26 is attached to the engine.
Although the side is attached, the reverse configuration may be adopted. Also, two sub liquid chambers of the first sub liquid chamber and the second sub liquid chamber are provided, but may be one sub liquid chamber. Only one orifice may be used. On the other hand, in the above-described embodiment, the purpose is to dampen the engine mounted on the vehicle.
It goes without saying that the vibration damping device of the present invention is used for other purposes, and the shape and the like are not limited to those of the embodiment. On the other hand, in the above embodiment, the rotor is configured to be rotated by the motor, but the present invention is not limited to this, and the actuator for rotating the rotor may be other than the motor, and the valve body may be a valve other than the rotor. Etc. may be used, and the rotor may not be provided.

[0055]

As described above, the vibration isolator according to the present invention can reduce vibrations of a wide range of frequencies without increasing the manufacturing cost.

[Brief description of the drawings]

FIG. 1 is a sectional view showing a first embodiment of a vibration isolator according to the present invention (however, legs are omitted), showing a state where an idle orifice is opened.

FIG. 2 is a view taken in the direction of arrow 2-2 in FIGS. 1 and 3 (however, legs are omitted).

FIG. 3 is a sectional view showing the first embodiment of the vibration isolator according to the present invention (however, legs are omitted), and is a view showing a state in which the orifice for the stagnation is opened.

FIG. 4 is a perspective view showing a first embodiment of a vibration isolator according to the present invention.

FIG. 5 is an exploded perspective view of a main part of a first diaphragm and an outer cylinder fitting applied to the first embodiment of the vibration isolator according to the present invention.

FIG. 6 is an exploded perspective view of an intermediate block and a rotor applied to the first embodiment of the vibration isolator according to the present invention.

FIG. 7 is a diagram showing an intermediate block applied to the first embodiment of the vibration isolator according to the present invention, wherein (A) is a left side view, (B) is a bottom view, (C) is a right side view.

FIG. 8 is a graph showing a relationship between a dynamic spring constant and a vibration frequency of the vibration isolator according to the first embodiment of the present invention.

FIG. 9 is a cross-sectional view (with legs omitted) showing a second embodiment of the vibration isolator according to the present invention.

FIG. 10 is a view taken in the direction of arrow 10-10 in FIG. 9 (however, legs are omitted).

FIG. 11 is a graph showing a relationship between a dynamic spring constant and a vibration frequency of the vibration isolator according to the second embodiment of the present invention.

FIG. 12 is a cross-sectional view of a vibration isolator according to the related art.

FIG. 13 is a view taken along the arrow 13-13 in FIG.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Vibration isolator 16 Outer cylinder fitting 20 1st diaphragm 20B Low rigidity part 20C High rigidity part 20D Low rigidity part 26 Inner cylinder fitting 28 Elastic body 30 Main liquid chamber 32 First subliquid chamber 60 Idle orifice 64 Shake orifice

Claims (6)

[Claims] A first mounting member connected to one of the vibration generating portion and the vibration receiving portion; a second mounting member connected to the other of the vibration generating portion and the vibration receiving portion; An elastic body that is arranged and elastically deformable; a main liquid chamber in which a liquid is sealed with the elastic body as a part of a partition wall and whose internal volume changes due to deformation of the elastic body; And a pair of low-rigid portions along the flow direction of the liquid flowing into and out of the sub-liquid chamber from the passage, and varying the rigidity by sandwiching the high-rigid portion between them. And a diaphragm for forming at least a part of a partition wall of the sub liquid chamber so as to be elastically deformable. 2. The vibration damping device according to claim 1, wherein the rigidity of the diaphragm is changed by changing the thickness of the diaphragm along the flow direction of the liquid. 3. The central portion of the diaphragm along the direction of flow of the liquid has a linear shape, and both ends along the direction of flow of the liquid are slackened with respect to the central portion. 2. The vibration isolator according to claim 1, wherein the rigidity of the diaphragm is varied. 4. An inner cylinder connected to one of the vibration generator and the vibration receiver, and an outer cylinder connected to the other of the vibration generator and the vibration receiver and formed into a cylindrical shape so as to surround the inner cylinder. An elastic body disposed between the inner cylinder and the outer cylinder and capable of being elastically deformed; a main liquid chamber in which a liquid is sealed with the elastic body as a part of a partition wall and the inner volume is changed by deformation of the elastic body; A sub-liquid chamber, which is in communication with the main liquid chamber via the passage and in which the liquid is sealed, and has a pair of low-rigid portions along the flow direction of the liquid flowing into and out of the sub-liquid chamber from the passage, and A diaphragm that varies the rigidity so as to sandwich the high-rigidity portion and forms at least a part of the partition wall of the auxiliary liquid chamber so as to be elastically deformable. 5. The vibration damping device according to claim 4, wherein the rigidity of the diaphragm is changed by changing the thickness of the diaphragm along the flow direction of the liquid. 6. A central portion of the diaphragm along the liquid flow direction is formed in a linear shape, and both ends along the liquid flow direction are slackened with respect to the central portion. 5. The vibration isolator according to claim 4, wherein the rigidity of the diaphragm is varied.