JP2002206591A - Liquid sealing type vibration control device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a compact liquid sealing type vibration control device which achieves a given vibration control effect to a vibration in a wide high frequency range, by making a vibration spring constant of a partition wall itself variable. SOLUTION: The partition wall 4 partitioning a liquid chamber into main and sub chambers 5, 6 connected and communicating through a limiting passage 9 is constituted to be displaceable in a direction for varying volumes of the main and sub liquid chambers 5, 6. An electromagnet 10 is integrally attached to the partition wall 4. A MR fluid 12 capable of increasing or decreasing a viscosity by regulating a strength of a magnetic field produced by the electromagnet 10 is interposed in a sealed state between an outer peripheral surface of the partition wall 4 and an inner peripheral surface of a cylindrical attaching member 2.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid-filled type vibration damping device mainly used for an engine mount for absorbing and attenuating vibration by elastically supporting an automobile engine on a vehicle body frame.

[0002]

2. Description of the Related Art A liquid-filled type vibration damping device of this type is provided in a hollow space formed by a mounting member connected to a vibration generating portion and a vibration receiving portion and an elastic body interposed between the mounting members. A partition wall is provided to define two main and sub liquid chambers, and a part of the sealed liquid in the main liquid chamber which is compressed as the elastic body is deformed when vibration is applied is formed between the two liquid chambers. In general, it is configured such that a fluid pressure fluctuation in the main liquid chamber is absorbed by flowing to the sub liquid chamber side through the restricted passage, thereby exhibiting an anti-vibration function.

However, in the liquid filled type vibration damping device having only the restricted passage as described above and the partition wall being fixed, when the vibration is in a low frequency region, the sealed liquid passes through the restricted passage and passes through the auxiliary liquid chamber. Since it flows to the side, it is possible to absorb the fluctuation of the liquid pressure in the main liquid chamber and attenuate the vibration, but if the vibration is in the high frequency range, it will be in the same state as the restricted passage is closed, Fluctuations in the liquid pressure in the main liquid chamber cannot be absorbed, and a predetermined vibration-proof performance cannot be ensured against high-frequency vibration.

Therefore, conventionally, a partition wall that partitions the two liquid chambers is formed of an elastic film using a rubber emma trama, and when a vibration in a high frequency region acts, the partition wall made of the elastic film is elastically displaced. There has been proposed one configured to absorb the fluctuation of the liquid pressure in the main liquid chamber and to dampen the vibration.

[0005]

However, in the case of the conventional liquid-filled type vibration damping device as described above, even if the partition wall is an elastic film, its rigidity is constant as long as it is a single member, and the vibration is reduced. Since the stiffness cannot be changed according to the frequency, only the anti-vibration effect is exerted for vibration in a specific (one or very narrow range) frequency region, and vibration in other frequency regions However, there is a problem that a sufficient anti-vibration effect cannot be exhibited.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and it is possible to make the dynamic spring constant of the partition wall itself variable so as to exhibit a predetermined vibration-proof effect against vibration in a wide high-frequency region. It is an object of the present invention to provide a liquid-filled type vibration damping device that can be made compact in size.

[0007]

To achieve the above object, a liquid filled type vibration damping device according to the present invention comprises a mounting member connected to one of a vibration generating portion and a vibration receiving portion and a connecting member connected to the other. In the hollow closed space formed by the mounting member and the elastic body provided between the mounting members, a partition wall that partitions the inside of the space into two main and sub-liquid chambers relatively reduces the volume of both the liquid chambers. The means for displacing the partition wall in the variable direction and the means for driving the partition wall in the liquid chamber volume variable direction include an MR fluid whose viscosity changes according to the magnitude of the magnetic field strength and a viscosity of the MR fluid. An electromagnet capable of controlling the magnetic field strength for changing the pressure is provided, and a restriction passage is provided for connecting the two liquid chambers to each other and absorbing a fluctuation in the liquid pressure in the main liquid chamber when vibration occurs. It is a liquid filled type vibration damping device , And it is characterized in that it integrally assembled to the electromagnet in the partition wall.

According to the present invention having the above-mentioned characteristic configuration, the magnitude of the magnetic field strength is adjusted by turning on / off the energization of the electromagnet or controlling the energization (applied) current to thereby reduce the MR fluid. The partition wall can be fixed at a fixed position by increasing or decreasing the viscosity, or the dynamic spring constant of the partition wall can be reduced by displacing the main and sub chambers in a direction in which the volumes of the two chambers are relatively variable. Under the conditions where vibration in the low-frequency region acts, the vibration-proof performance inherent in the liquid-ring type vibration-proof device inherently limited to the enclosed liquid in the main liquid chamber to the sub-liquid chamber side is ensured. In addition, under conditions where vibrations in the high-frequency region act, by adjusting the dynamic spring constant of the partition wall, it is possible to arbitrarily and responsively change the bulk modulus of both the main and sub liquid chambers. Wide, high frequency range It is possible to exhibit a sufficient vibration damping effect against vibration.

In addition, the electromagnet for controlling the magnetic field strength for changing the viscosity of the MR fluid is integrally mounted on the partition wall, so that the electromagnet is disposed on the outer peripheral portion of the partition wall. It is possible to make the whole apparatus compact.

In particular, in the liquid filled type vibration damping device as described above, a central portion of a diaphragm for forming an air chamber filled with gas on the side of the main liquid chamber so as to face the main liquid chamber. Is integrally connected to the partition wall, and the control line for the electromagnet integrally mounted on the partition wall is drawn out to the outside through the integrated connection portion, thereby bringing the control line into contact with the sealed liquid in the liquid chamber. As a result, a special sealing structure for the control lines is not required, which makes it possible to reduce the size of the entire device, simplify the structure, and reduce the cost. The dynamic spring constant of the partition wall during the vibration action in the high frequency range can be further reduced by the integral connection with the .

It is most preferable that the partition wall is circular and that the MR fluid disposed on the outer peripheral portion is of an annular shape. However, the partition wall is elliptical or rectangular, and the MR fluid has a corresponding shape. An elliptical ring shape or a rectangular ring shape may be used.

[0012]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 shows a longitudinal section structure of a liquid-filled vibration damping device according to the present invention. The liquid-filled vibration damping device has a mounting member 1 connected to a vibration generating source side such as an engine for a vehicle and a mounting member 1 for a vehicle. A bottomed cylindrical mounting member 2 made of a ferromagnetic material such as iron, cobalt, or nickel, and both mounting members 1, which are connected and mounted on a vibration receiving portion side of a frame or the like.
A substantially circular conical elastic rubber (elastic body) interposed between the two
By disposing the partition wall 4 in the hollow closed space formed by 3, two main and sub liquid chambers 5 and 6 are formed on both sides of the partition wall 4.

The partition wall 4 has two main and sub liquid chambers 5,
6, two disc-shaped plate portions 4A and 4B made of a ferromagnetic material and arranged in parallel and opposed to each other so as to face 6;
A and a boss portion 4C that integrally connects the 4B at the center thereof, and the bottomed cylindrical mounting member 2 is mainly used as a cylinder.
The sub two liquid chambers 5 and 6 are configured so as to be displaceable in the a-b direction that relatively changes the volume.

On the bottom side of the main liquid chamber 5, an air chamber 8 in which gas (air) is sealed via a diaphragm 7 is formed so as to face each other. Further, the bottomed cylindrical mounting member 2
The two liquid chambers 5 and 6 are communicated with each other, and a part of the sealed liquid in the main liquid chamber 5 which is compressed due to the elastic deformation of the elastic rubber 3 at the time of vibration is caused to flow to the sub liquid chamber 6 side. In addition, a buffering restriction passage 9 is formed to absorb the fluctuation of the liquid pressure in the main liquid chamber 5 in conjunction with the deformation of the diaphragm 8.

An electromagnet 10 is integrally attached to the partition wall 4 while being sandwiched between the two disk-shaped plate portions 4A and 4B. Between the outer peripheral surface of the partition wall 4 including the electromagnet 10 and the inner peripheral surface of the bottomed tubular mounting member 2, both ends in the displacement direction of the partition wall 4 are annular elastic rubbers 11, respectively.
An MR fluid 12 whose viscosity varies according to the magnitude of the magnetic field strength is interposed in a sealed state in the annular gap sealed by 11, and energization / deactivation of the electromagnet 10 and control of the energization current are carried out. Disc-shaped plate 4B → MR fluid 12 →
Attachment member 2 → Disc-shaped plate 4A → Adjust the magnitude of the magnetic field flowing through the magnetic path formed by electromagnet 10 to adjust the MR fluid 12
By changing the viscosity of the partition wall 4, the partition wall 4 can be fixed in position and can be driven to be displaced in the above-described a-b directions.

A hole 7a is formed in the center of the diaphragm 7, and the peripheral edge of the hole 7a is integrally connected to a boss 4C at the center of the partition wall 4, and the integrally connected portion and the air A control line 13 for the electromagnet 10 is drawn through the chamber 8 to the outside.

The MR fluid 12 is a Bingham fluid in which fine ferromagnetic metal particles having a particle diameter of about 1 to 10 μm are dispersed in a high-concentration suspension.
It has an operating temperature range of ° C., and its viscosity changes depending on the magnitude of the magnetic field strength, and is called a magnetorheological fluid or a magnetorheological fluid.

In the liquid filled type vibration damping device having the above structure,
Under the condition where the vibration in the low frequency region acts, the electromagnetic fluid switch (not shown) is turned on to apply a constant applied current to the electromagnet 10 to increase the magnetic field strength formed in the magnetic path, thereby increasing the MR fluid 12. And the dynamic spring constant of the partition wall 4 increases, and the partition wall 4 is fixed in position. In this state, the sealed liquid in the main liquid chamber 5 that is compressed due to the deformation of the elastic rubber 3 due to the vibration is restricted to the sub liquid chamber 6 via the restriction passage 9 and the hydraulic pressure in the main liquid chamber 5 is reduced. The fluctuations are absorbed, whereby the vibration in the low frequency region is attenuated, and the predetermined vibration isolation performance can be secured.

On the other hand, under the condition that the vibration in the high frequency region acts, the electromagnet switch is turned off to stop the energization to the electromagnet 11, or the magnitude of the magnetic field strength is adjusted by increasing or decreasing the energizing current. As a result, the viscosity of the MR fluid 12 is changed in the decreasing direction, and the dynamic spring constant of the partition wall 4 becomes smaller than when the power is supplied. As a result, the bulk modulus of the main and sub liquid chambers 5 and 6 is changed with good responsiveness in accordance with the vibration frequency, so that a sufficiently large vibration damping effect is exerted against vibration in a wide high frequency range. be able to.

Here, in particular, by assembling the electromagnet 10 for controlling the magnetic field strength for increasing and decreasing the viscosity of the MR fluid 12 integrally with the partition wall 4 itself, this electromagnet 1
The entire apparatus can be made more compact as compared to the case where the O is fixed to the outer peripheral portion of the partition wall 4 by, for example, fixing to the mounting member 2. Further, when the control line 13 for the electromagnet 10 integrally attached to the partition wall 4 is drawn out, the central portion of the diaphragm 7 and the partition wall 4 for forming the air chamber 8 on the main liquid chamber 5 side in an opposed state. Control line 1 by pulling it out through an integral connection with the
3 can be drawn out to the outside without making contact with the sealed liquid in the liquid chamber 5, and as a result, a special sealing structure for the control line 13 is not required. Can be achieved. Further, by integrally connecting the diaphragm 7 and the partition wall 4, the dynamic spring constant of the partition wall 4 can be further reduced, and the vibration damping effect in a high frequency region can be further enhanced.

FIG. 2 is a vertical sectional view showing another embodiment of the liquid-filled type vibration damping device according to the present invention. In this embodiment, the partition wall 4 has a main liquid chamber 5 side and a sub liquid chamber 6. Only the electromagnets 10A and 10B are integrally fixed and assembled on the surfaces facing the sides, and the restriction wall 9 is formed in the partition wall 4 itself, which is different from the embodiment shown in FIG.
Since other configurations are the same as those of the embodiment of FIG. 1, corresponding portions are denoted by the same reference numerals, and detailed description of those structures is omitted.

In the liquid-filled type vibration damping device according to the other embodiment, the partition wall 4 is fixed to the vibration in the low frequency region, and the liquid filled in the main liquid chamber 5 is supplied through the restriction passage 9 to the auxiliary liquid. A predetermined vibration damping performance is exhibited by the fluid pressure fluctuation absorbing action in the main fluid chamber 5 due to the restricted flow to the fluid chamber 6 side, and the MR fluid 12 is protected against vibration in a high frequency region.
1 is reduced by reducing the dynamic spring constant of the partition wall 4 as the viscosity decreases, and changing the bulk modulus of the two main and sub liquid chambers 5 and 6 with good responsiveness. It is possible to exhibit the same vibration damping effect as the device shown by.

In each of the above embodiments, the partition wall 4
Is circular, the electromagnets 10, 10A, and 10B are annular, and the MR fluid 12 is also annularly interposed. However, when the partition wall 4 is elliptical or rectangular, the It goes without saying that the shapes of the electromagnets 10, 10A and 10B and the interposed shape of the MR fluid 12 may be an elliptical ring shape or a rectangular ring shape.

[0024]

As described above, according to the present invention, a partition wall can be fixed or a partition wall can be fixed by a combination of an electromagnet and an MR fluid whose viscosity changes depending on the magnitude of a magnetic field generated by the electromagnet. The dynamic spring constant of the partition wall itself can be changed arbitrarily by displacing the main and sub two liquid chambers in a direction in which the volume of the two liquid chambers is relatively varied. While the liquid ring type vibration isolator can secure the predetermined vibration isolation performance by the fluid pressure fluctuation absorbing action in the main liquid chamber originally provided,
With respect to vibration in the high frequency region, the bulk modulus of both the main and sub liquid chambers can be changed arbitrarily and with good responsiveness.
As a result, a sufficient anti-vibration effect can be exhibited even for vibration in a wide high-frequency region.

Further, by integrally attaching the electromagnet for controlling the magnetic field strength for changing the viscosity of the MR fluid to the partition wall, the entire apparatus can be compared with the case where the electromagnet is disposed on the outer peripheral portion of the partition wall. Can be designed and manufactured in a compact manner.

In particular, by adopting the configuration as set forth in claim 2, the control line for the electromagnet integrally mounted on the partition wall can be drawn out without contacting the sealed liquid. , No special sealing structure for the control line is required, and the structure is simplified as well as the compact design.
Cost reduction can be achieved.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional structural view showing an embodiment of a liquid filled type vibration damping device according to the present invention.

FIG. 2 is a longitudinal sectional structural view showing another embodiment of the liquid filled type vibration damping device according to the present invention.

[Explanation of symbols]

 1, 2 mounting member 3 elastic rubber 4 partition wall 5 main liquid chamber 6 sub liquid chamber 7 diaphragm 8 air chamber 9 restriction passage 10, 10A, 10B electromagnet 12 MR fluid 13 control line 14 magnetic path

Claims (2)

[Claims] A mounting member connected to one of a vibration generating portion and a vibration receiving portion, a mounting member connected to the other, and a hollow closed space formed by an elastic body provided between the mounting members. A partition wall for partitioning the interior of the space into a main and a sub-liquid chamber is provided so as to be displaceable in a direction in which the volumes of the two liquid chambers are relatively varied, and the partition wall is moved in the above-described liquid chamber volume variable direction. Fluids whose viscosity changes depending on the magnitude of the magnetic field,
An electromagnet capable of controlling the magnetic field strength for changing the viscosity of the R fluid is provided, and a restriction passage that connects the two liquid chambers to each other to absorb a fluctuation in the liquid pressure in the main liquid chamber when vibration occurs is provided. A liquid-filled type vibration damping device provided, wherein the electromagnet is integrally attached to a partition wall. 2. An air chamber filled with a gas is formed on the main liquid chamber side through a diaphragm so as to face each other.
The center part of the diaphragm is integrally joined to the partition wall,
2. The liquid-filled type vibration damping device according to claim 1, wherein a control line for the electromagnet integrally mounted on the partition wall is drawn out to the outside through the integral connecting portions.