JP2004301333A - Liquid sealing type vibration absorption device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide sufficient damping effect for vibration in a wide high frequency zone by providing bulkhead itself for partitioning with an adjusting function for resonance frequency. <P>SOLUTION: The bulkhead 8 for partitioning for dividing two main and auxiliary liquid chambers 10, 9 communicated and connected mutually through an orifice 11 for buffering is constituted by a laminated structure of a plurality of magnetic substance plates 8A, 8C, 8B and MR fluid 12B, 12A provided between adjacent magnetic substance plates 8A and 8C and between 8A and 8B in a sealed condition. An electromagnet 17 capable of adjusting magnetic field strength to change viscosity of MR fluid 12B, 12A is arranged in outer surroundings of the bulkhead 8 for partitioning of the laminated structure. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid-filled vibration absorber used mainly for an engine mount that absorbs and attenuates vibration by elastically supporting an automobile engine on a vehicle body.

  In this type of liquid-filled vibration absorbing device, two main and sub liquid chambers are defined by providing a partitioning partition inside a hollow main body including an elastic body such as elastic rubber and a diaphragm. A part of the filled liquid in the main liquid chamber, which is compressed due to the deformation of the elastic rubber, flows through the buffer orifice to the sub liquid chamber, thereby absorbing the fluctuation of the liquid pressure in the main liquid chamber and vibrating. Is generally attenuated.

  However, as described above, in the liquid-filled vibration absorbing device having only the buffer orifice and the partition wall fixed, when the vibration is in a low frequency region, the sealed liquid passes through the orifice and moves to the sub liquid chamber side. Since the fluid flows, it is possible to absorb the fluctuation of the liquid pressure in the main liquid chamber and attenuate the vibration.However, when the vibration is in a high frequency range, the state becomes the same as when the orifice is closed. Cannot absorb the fluctuation of the hydraulic pressure, and cannot attenuate the high frequency vibration.

Therefore, conventionally, (1) a partition wall for partitioning two liquid chambers is formed of an elastic film using a rubber emma trama, and when vibration in a high frequency region acts, the partition wall made of the elastic film is elastically displaced. (2) A part of the side wall of the main liquid chamber is formed as a movable plate or a vibrating plate as disclosed in Patent Documents 1 and 2, for example. (Hereinafter referred to as a movable plate or the like), and by displacing the movable plate or the like through an electromagnetic force by a combination of an electromagnet and a magnetic fluid, the main liquid chamber inside the main liquid chamber when a high frequency vibration is applied. A device configured to absorb a change in hydraulic pressure has been proposed.
JP-A-7-224885 JP-A-5-164181

  However, in the case of the conventional liquid-encapsulated vibration absorbing device such as the former (1), even if the partition wall is an elastic film, its rigidity is constant as long as it is one member, and the rigidity depends on the vibration frequency. Cannot be changed, so that only a damping effect is exerted on vibrations in a specific (one or very narrow range) frequency region, and sufficient for vibrations in other frequency regions. The damping effect cannot be exhibited.

  Further, in the conventional liquid-filled vibration absorbing device such as the latter (2), only the liquid pressure in the main liquid chamber can be adjusted by the displacement of the movable plate or the like, and the resonance frequency cannot be adjusted, or Since the adjustment can be performed only in a limited narrow frequency range, there is a problem that the damping effect on vibrations in a wide range of high frequency regions is insufficient.

  The present invention has been made in view of the above-described circumstances, and allows the partitioning partition itself to have a function of adjusting the resonance frequency, thereby exhibiting a sufficient damping effect on vibration in a wide range of high frequencies. It is an object of the present invention to provide a liquid-filled vibration absorbing device that can be used.

  In order to achieve the above object, a liquid-filled vibration absorbing device according to the present invention has two main and sub liquid chambers formed inside a hollow main body including an elastic body via a partition wall. The main and sub liquid chambers communicate with each other to cause a part of the sealed liquid in the main liquid chamber, which is compressed due to the deformation of the elastic body when vibration is applied, to flow to the sub liquid chamber, thereby causing the liquid in the main liquid chamber to flow. In a liquid-filled vibration absorbing device provided with a buffer orifice for absorbing pressure fluctuations, the partitioning partition is composed of a plurality of magnetic plates and ferromagnetic metal fine particles dispersed in a liquid depending on the magnitude of a magnetic field. It has a laminated structure with an MR fluid interposed between adjacent magnetic plates in a sealed state so that the viscosity changes, and the outer peripheral portion of the partition wall of the laminated structure has a viscosity of the MR fluid. Adjust magnetic field strength for change Ability electromagnet is characterized in that it is arranged in an annular.

  According to the present invention having the above-mentioned characteristic configuration, the magnetic field strength is adjusted by controlling the energizing (applied) current to the electromagnet to increase or decrease the viscosity of the MR fluid. It is possible to arbitrarily vary the stiffness and the vibration amplitude over a wide range. In this way, by providing the partitioning partition itself with a vibration resonance system, that is, a function of adjusting the resonance frequency, the viscosity of the MR fluid is maximized under the action of vibration in a low frequency range, thereby making the partitioning partition rigid. In this way, vibration is attenuated by the original hydraulic pressure absorption function of flowing the sealed liquid in the main liquid chamber through the buffer orifice to the sub liquid chamber, while under the vibration action in the high frequency region, the vibration is attenuated due to the viscosity adjustment of the MR fluid. By arbitrarily changing the rigidity of the partition wall itself, the resonance frequency can be finely adjusted over a wide range, and a sufficient damping effect can be exerted on vibrations in a wide range of high frequencies.

  In particular, by providing at least two or more MR fluid layers in the stacking direction in the partitioning partition having a laminated structure, the variable range of the rigidity and vibration amplitude of the partitioning partition, that is, the adjustment range of the resonance frequency is expanded, and The bulk elastic modulus of the two sub chambers can be changed with good responsiveness, and the damping performance against vibration in a high frequency range can be further improved.

  In addition, by forming the magnetic plates facing the main liquid chamber and the sub-liquid chamber out of a plurality of magnetic plates constituting the partition wall of the laminated structure in the above-described liquid-enclosed vibration absorber, the magnetic plates are made thinner. The magnetic plate facing both the main and sub liquid chambers can be controlled like an elastic film, and the rigidity and vibration amplitude of the entire partition wall due to the change in the viscosity of the MR fluid change, and each elastic film (thin magnetic material) Plate) and the change in individual stiffness can be synergized to further improve the vibration damping performance in the high frequency region.

  Further, in the above-described liquid-filled vibration absorbing device, the variable range of the rigidity of the magnetic plate itself may be achieved by supporting one or both of the magnetic plates facing the main liquid chamber and the sub liquid chamber via an elastic body. And the attenuation frequency range can be further expanded.

  The partitioning walls, the electromagnets arranged in an annular shape around the outer periphery thereof are preferably circular, but are not limited to a circle, and may be elliptical or rectangular. , A circle, an ellipse, a rectangle, or a donut.

  As described above, according to the present invention, the partition that separates the main liquid chamber and the sub liquid chamber can arbitrarily increase or decrease the viscosity by adjusting the magnetic field strength through control of the energizing (applied) current to the electromagnet. Since it is composed of a laminated structure of an MR fluid and a plurality of magnetic plates that can be controlled, the rigidity and vibration amplitude of the partition wall can be set arbitrarily and in a wide range in accordance with the vibration frequency. The partitioning partition itself can be provided with a function of adjusting the resonance frequency so as to be variable. Therefore, under the vibration action in the low frequency region, the vibration can be attenuated by the original liquid pressure absorbing action that the enclosed liquid in the main liquid chamber flows to the sub liquid chamber through the buffer orifice with the rigidity of the partition wall. In addition, under the action of vibration in the high frequency range, the resonance frequency can be finely adjusted over a wide range by arbitrarily changing the rigidity of the partition wall itself, and sufficient attenuation can be achieved for vibration in a wide range of high frequency range. The effect that the effect can be exhibited is produced.

  In particular, by adopting the configuration as described in claims 2 to 4, the damping performance with respect to vibration in a wide range of high frequency ranges can be further improved.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
[Example 1]

  FIG. 1 shows a longitudinal section structure of a liquid-filled vibration absorbing device according to a first embodiment. The liquid-filled vibration absorbing device includes a mounting bracket 1 that can be mounted on a vibration source such as an automobile engine, and a ring-shaped mounting device. A main metal fitting 2, a conical body elastic rubber 3 connected between the two metal fittings 1 and 2, an annular mounting member 4 attachable to a vibration receiving portion side of an automobile frame or the like; A hollow main body 7 is constituted by a cylindrical member 5 made of a magnetic material for fixedly connecting the main member 2 and the main member 2 and a diaphragm 6 stretched and held in the mounting member 4. By disposing a circular partition wall 8 inside the cylindrical member 5 of the main body 7, two main and sub liquid chambers 10 and 9 are defined above and below the partition wall 8, respectively.

  Between the two main and sub liquid chambers 10, 9, the two liquid chambers 10, 9 communicate with each other, and the sealed liquid in the main liquid chamber 10 is compressed by the elastic deformation of the elastic rubber 3 when vibration is applied. A buffer orifice 11 is provided for absorbing a part of the fluid pressure fluctuation in the main liquid chamber 10 together with the deformation of the diaphragm 6 by flowing a part of the diaphragm to the sub liquid chamber 9 side.

  In the liquid-filled vibration absorbing device having the basic configuration as described above, the partitioning partition 8 has a thick magnetic plate 8A located at the center in the thickness direction, as shown in FIG. The thin magnetic plates 8C and 8B arranged so as to face the main liquid chamber 10 and the sub liquid chamber 9 on both sides, respectively, and the thin magnetic plates 8C and 8B and the thick magnetic plate 8A at the center. It has a laminated structure with MR fluids 12B and 12A interposed in a sealed state between them.

  The partition wall 8 having the above-mentioned laminated structure is connected to electromagnet yoke members 14B, 14A to be described later via non-magnetic or weak magnetic members 13B, 13A on the front and back of the outer peripheral edge of the central thick magnetic plate 8A. While being supported, the thin magnetic plates 8C, 8B on both sides are supported by the yoke members 14B, 14A via elastic bodies 15B, 15A such as rubber elastomers and coil springs at their outer peripheral edges. An orifice 16 is formed in the central thick magnetic plate 8A to connect the MR fluids 12B and 12A to each other. The orifice 16 may not be provided.

  An electromagnet 17 is arranged in an annular shape coaxially with the partition wall 8 around the outer periphery of the partition wall 8 having the above-mentioned laminated structure, and the yoke members 14B, 14B, 14A is fixed to the upper and lower end surfaces of the cylindrical member 5 in the main body 7, and the yoke members 14B, 14A, the magnetic plates 8C, 8A, 8B, the MR fluids 12B, 12A, and the magnetic material formed by the cylindrical member 5. The magnetic field strength for changing the viscosity of the MR fluids 12B and 12A can be adjusted by controlling the current supplied to the electromagnet 17 via the path.

  The buffer orifice 11 has a passage 11a formed in one yoke member 14B so as to open and connect to the main liquid chamber 10, and has a sub-angle of 180 ° with respect to the passage 11a. A passage 11b formed in the other yoke member 14A so as to open and connect to the liquid chamber 9, and a passage 11c formed in a semi-annular shape in the cylindrical member 5 so that both ends are connected to the two passages 11a and 11b. It consists of: The MR fluids 12B and 12A are Bingham fluids in which ferromagnetic metal fine particles having a particle diameter of about 1 to 10 μm are dispersed in a high-concentration suspension, and have an operating temperature range of −40 to 150 ° C. The 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 vibration absorbing device having the above-described configuration, under conditions where vibrations in a low frequency range act, an electromagnet switch (not shown) is turned on to energize the electromagnet 17 to increase the magnetic field strength formed in the magnetic path. By adjusting the viscosity of the MR fluids 12B and 12A to the maximum, the partition walls 8 of the laminated structure are made rigid. In this state, the enclosed liquid in the main liquid chamber 10 which is compressed due to the vibration is passed through the buffer orifice 11 and flows to the sub liquid chamber 9 side. Vibration can be sufficiently attenuated.

On the other hand, under conditions where vibrations in the high frequency region act, the electromagnet switch is turned off to stop energization of the electromagnet 17, or the electromagnet switch is turned on to control the energization current to the electromagnet 17 to control the magnetic path. The rigidity and vibration amplitude of the entire partition wall 8 can be arbitrarily and widely set by reducing the intensity of the formed magnetic field to zero or adjusting the size to increase or decrease the viscosity of the MR fluids 12B and 12A. In addition to being able to change over time, the thin magnetic plates 8C and 8B themselves facing the main and sub liquid chambers 10 and 9 can be individually changed in rigidity like an elastic film. In addition, the resonance frequency of the partition wall 8 can be finely adjusted over a wide range, and a sufficiently large damping effect can be exerted on vibrations in a wide range of high frequencies.
[Examples 2 and 3]

FIG. 3 shows a longitudinal sectional structure of the liquid-filled vibration absorbing device of the second embodiment, and FIG. 4 shows a longitudinal sectional structure of the liquid-filled vibration absorbing device of the third embodiment. The MR fluids 12B, 12A are used to reduce the amount of use of the MR fluids 12B, 12C that are hermetically sealed between the central thick magnetic plate 8A and the thin magnetic plates 8C, 8B on both sides of the MR fluid 12B. In the second embodiment, cylindrical elastic films 18B, 18A are stretched between the central portions of the thick magnetic plate 8A at the center and the thin magnetic plates 8C, 8B on both sides thereof. The third embodiment is different from the first embodiment in that the cylindrical rubber elastic bodies 19B and 19A are interposed and the inside of the cylindrical elastic films 18B and 18A and the cylindrical rubber elastic bodies 19B and 19A is an air layer. The other configuration is the same as that of the first embodiment. Because it is, detailed description of the structure of them are denoted by the same reference numerals to the corresponding portions is omitted.
[Example 4]

FIG. 5 shows a vertical cross-sectional structure of a liquid-filled vibration absorbing device according to a fourth embodiment. In the fourth embodiment, uneven portions 8a are formed on both front and back surfaces of a thick magnetic plate 8A at the center of a partition wall 8. By changing the layer thickness of the MR fluids 12B and 12A, the magnetic flux is concentrated on a plurality of convex portions of the concave and convex portions 8a so that the viscosity of the MR fluids 12B and 12A can be efficiently changed by controlling the supplied current. Since the configuration is different from that of the first embodiment and the other configuration is the same as that of the first embodiment, the corresponding portions are denoted by the same reference numerals and the detailed description of those components is omitted.
[Example 5]

FIG. 6 shows a longitudinal sectional structure of the liquid-filled vibration absorbing device of the fifth embodiment. In the fifth embodiment, a gap 20 is provided at the center of gravity of the thick magnetic plate 8A at the center of the partitioning wall 8, and This embodiment differs from the first embodiment in that the intervening layers of the MR fluids 12B and 12A are divided in the horizontal direction by an elastic rubber seal 21, and other configurations are the same as those in the first embodiment. A detailed description of those structures will be omitted.
[Example 6]

  FIG. 7 shows a vertical cross-sectional structure of a liquid-filled vibration absorbing device according to a sixth embodiment. In the sixth embodiment, a partitioning wall 8 is formed by a magnetic plate 8A located at the center in the thickness direction and both sides of the magnetic plate 8A. The thin magnetic plates 8C and 8B arranged so as to face the main liquid chamber 10 and the sub liquid chamber 9, and another thin magnetic plates 8C and 8B and another magnetic plate 8A disposed between the thin magnetic plates 8C and 8B and the central magnetic plate 8A, respectively. The thin magnetic plates 8E, 8D are interposed between the thin magnetic plates 8E, 8D and the central thick magnetic plate 8A and between the adjacent thin magnetic plates 8C, 8E, 8B, 8D in a sealed state. And a variable range of the rigidity and vibration amplitude of the entire partition wall 8 as compared with the above-described first to fifth embodiments, and a variable structure of the MR fluids 12D, 12C, 12B, and 12A. Is the same as in the first embodiment. Detailed description of the structure of those in the corresponding portion are denoted by the same reference numerals will be omitted.

  In any of the liquid-enclosed vibration absorbing devices of the above-described Embodiments 2 to 6, for the vibration in the low frequency region, the sealed liquid in the main liquid chamber 10 compressed along with the addition of the vibration passes through the buffer orifice 11. A large damping coefficient is obtained by the inherent action of the liquid-filled vibration absorbing device such as passing through and flowing to the sub-liquid chamber 9 to absorb the fluctuation of the liquid pressure in the main liquid chamber 10. That is, the rigidity and vibration amplitude of the entire partition wall 8 can be arbitrarily varied over a wide range, the resonance frequency of the partition wall 8 can be finely adjusted over a wide range, and a wide range of high frequency ranges can be obtained. It is possible to exhibit a vibration reduction effect substantially similar to that of the first embodiment, such as exhibiting a sufficiently large damping effect on vibration.

  In each of the above embodiments, the magnetic plate 8C facing the main liquid chamber 10 and the magnetic plate 8B facing the sub liquid chamber 9 have the same thickness. The size (diameter) may be changed. Further, in each of the above embodiments, one or more orifices 16 for connecting the layers of the MR fluids 12B and 12A to each other are provided, but this orifice may not be provided.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a vertical sectional view of a liquid-filled vibration absorbing device according to a first embodiment of the present invention. FIG. 2 is an enlarged vertical sectional view of a main part of FIG. 1. FIG. 6 is a vertical sectional view of a liquid-filled vibration absorbing device according to a second embodiment of the present invention. FIG. 9 is a longitudinal sectional view of a liquid-filled vibration absorbing device according to a third embodiment of the present invention. FIG. 8 is a longitudinal sectional structural view of a liquid-filled vibration absorbing device according to a fourth embodiment of the present invention. FIG. 13 is a longitudinal sectional view of a liquid-filled vibration absorbing device according to a fifth embodiment of the present invention. FIG. 14 is a longitudinal sectional view of a liquid-filled vibration absorbing device according to a sixth embodiment of the present invention.

Explanation of reference numerals

REFERENCE SIGNS LIST 3 body elastic rubber 6 diaphragm 7 hollow body 8 partition wall 8A to 8E magnetic plate 9 auxiliary liquid chamber 10 main liquid chamber 11 buffer orifice 12A to 12D MR fluid 15A, 15B elastic body 17 electromagnet

Claims (4)

Two main and sub-liquid chambers are formed inside a hollow main body including an elastic body via a partition wall, and the two main liquid chambers and the two sub-liquid chambers are communicated with each other to provide an elastic body when vibration is applied. In the liquid-filled vibration absorbing device, there is provided a buffer orifice for absorbing part of the liquid pressure in the main liquid chamber by flowing a part of the liquid sealed in the main liquid chamber to the sub liquid chamber side due to the deformation of the liquid. ,
The partition wall is composed of a plurality of magnetic plates, and an MR fluid interposed between adjacent magnetic plates in a sealed state such that ferromagnetic metal fine particles are dispersed in a liquid and the viscosity changes depending on the magnitude of a magnetic field. And a laminated structure of
A liquid-enclosed vibration absorbing device characterized in that an electromagnet capable of adjusting the magnetic field strength for changing the viscosity of the MR fluid is disposed in an annular shape around the outer periphery of the partition wall of the laminated structure. .   2. The liquid-filled vibration absorbing device according to claim 1, wherein the partition wall having the laminated structure includes at least two or more MR fluid layers in the laminating direction.   The magnetic plate facing the main liquid chamber and the sub liquid chamber is formed to be thinner than other magnetic plates among a plurality of magnetic plates constituting the partition wall of the laminated structure. 6. A liquid-filled vibration absorbing device according to item 5. 2. A plurality of magnetic plates constituting the partition wall of the laminated structure, at least one or both of the magnetic plates facing the main liquid chamber and the sub liquid chamber are supported via an elastic body. 3. 4. The liquid-filled vibration absorbing device according to any one of items 1 to 3.

Images