JP2004301332A - Liquid sealing type vibration absorption device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To develop predetermined damping effect for vibration in a wide high frequency zone by making rigidity of bulkhead itself for partitioning variable. <P>SOLUTION: A bulkhead 7 for partitioning for dividing two main and auxiliary liquid chambers 9, 8 communicated and connected mutually through an orifice 10 for buffering is constituted like a piston displaceable in the direction in which volume of two main and auxiliary liquid chambers 9, 8 is changed. An electromagnet 11 is annularly arranged in an outer peripheral part of the bulkhead 7 like the piston to constitute a part of a main body 6. MR fluid 15 whose viscosity is changed depending on magnitude of magnetic field strength is provided between the electromagnet 11 and the bulkhead 7 like the piston in a sealed condition. <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, a partition wall that partitions the two liquid chambers is formed of an elastic film using a rubber emma tramer or the like, and when 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 liquid chamber.

  However, in the case of the above-described conventional liquid-filled vibration absorbing device, even if the partition wall is an elastic film, its rigidity is constant as long as it is one member, and the rigidity changes according to the vibration frequency. Because it is not possible, only a damping effect is exhibited for vibrations in a specific (one or very narrow range) frequency region, and sufficient damping effect is obtained for vibrations in other frequency regions. There was a problem that it could not be demonstrated.

  SUMMARY OF THE INVENTION The present invention has been made in view of the above-described circumstances, and a liquid-filled type vibration that can exhibit a predetermined damping effect with respect to vibration in a wide high frequency range by making the rigidity of the partition wall itself variable. It is intended to provide an absorption device.

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 partition wall is composed of a piston-like member made of a ferromagnetic material that can be displaced in a direction in which the volumes of the main and sub liquid chambers can be varied. An electromagnet is arranged annularly concentrically with the piston-like partition so as to constitute a magnet, and between the annular electromagnet and the piston-like partition, ferromagnetic metal fine particles are dispersed in a liquid to form a magnetic field. It is characterized in that an MR fluid whose viscosity changes according to the magnitude of the strength is interposed in a sealed state.

  According to the present invention having the above-described features, the energization to the electromagnet is turned on / off, and the energization (application) current is controlled to adjust the magnitude of the magnetic field strength and reduce the viscosity of the MR fluid. By increasing or decreasing, the partitioning piston-shaped partition wall is fixed at a fixed position in the low frequency region, and the volume of the main and sub two liquid chambers is relatively varied in the high frequency region. By changing the rigidity of the partition wall itself by displacing in the direction, it is possible to arbitrarily and responsively change the bulk modulus of both the main and sub liquid chambers. As a result, the peak frequency of the damping coefficient when the vibration in the high frequency region acts can be varied to exert a sufficient damping effect on the vibration in a wide high frequency region.

  The piston-like partition in the liquid-filled vibration absorbing device as described above is made of a non-magnetic or weak magnetic material in view of the fact that the leakage magnetic flux is reduced and the piston-like partition is reliably and smoothly driven and displaced with low power consumption. And a ring portion formed of a ferromagnetic material such as iron, cobalt, nickel or the like that forms a part of a magnetic path together with a yoke connected to both poles of the electromagnet. .

  It is most preferable that the electromagnet, the MR fluid and the piston-like partition are all annular, but they may be elliptical or rectangular.

  As described above, according to the present invention, the combination of the electromagnet and the MR fluid whose viscosity changes according to the magnitude of the magnetic field generated by the electromagnet fixes the partitioning piston-shaped partition wall, and allows the primary and secondary parts to be fixed. Since the rigidity of the partition wall itself can be changed by displacing the volume of the two liquid chambers in a direction that can be relatively varied, the liquid ring vibration absorber is inherently provided for vibration in the low frequency range. In addition to ensuring a high damping coefficient and sufficiently reducing vibration, if the vibration in the high frequency range acts, change the bulk modulus of both the main and sub liquid chambers arbitrarily and with good responsiveness. This makes it possible to vary the peak frequency of the damping coefficient, and thus has the effect of exhibiting a sufficient damping effect even for vibration in a wide high-frequency region.

  In particular, by adopting the configuration as set forth in claim 2, the leakage flux is reduced, the piston-shaped partition wall is reliably and smoothly driven and displaced with low power consumption, and the predetermined vibration damping effect is ensured. Can be achieved.

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

  FIG. 1 shows a longitudinal sectional structure of a liquid-filled vibration absorbing device according to a first embodiment. This liquid-filled vibration absorbing device has a mounting bracket 1 that can be mounted on a vibration source side of an automobile engine or the like, and an annular main body. A metal fitting 2, a conical body elastic rubber 3 connected between the metal fittings 1 and 2, an annular mounting member 4 that can be mounted on a vibration receiving portion side of a frame for an automobile or the like, and stretched inside the mounting member 4. A partition wall 7 is installed inside a hollow main body 6 from the held diaphragm 5, and two main and sub liquid chambers 9 and 8 are formed above and below the partition wall 7. ing.

  Between the two main and sub liquid chambers 9, 8, the two liquid chambers 9, 8 communicate with each other, and the sealed liquid in the main liquid chamber 9 is compressed by the elastic deformation of the elastic rubber 3 when vibration is applied. A buffer orifice 10 is provided to absorb a part of the pressure in the main liquid chamber 9 together with the deformation of the diaphragm 5 by causing a part of the fluid to flow to the sub liquid chamber 8 side.

  In the liquid-filled vibration absorbing device having the basic configuration as described above, the partitioning wall 7 is made of a disk-shaped main body 7A made of a nonmagnetic or weak magnetic material and a ferromagnetic material such as iron, cobalt, or nickel. And a ring-shaped member 7B, which is a piston-like member that can be displaced in the a-b direction that relatively varies the volumes of the two main and sub liquid chambers 9, 8.

  An electromagnet 11 is annularly arranged concentrically with the piston-like partition 7 so as to constitute a part of the main body 6 around the outer periphery of the ring portion 7B of the piston-like partition 7. A magnetic path 14 is formed by the annular yokes 12 and 13 connected to both pole portions and the ring portion 7B of the piston-like partition wall 7. The buffer orifice 10 has a passage 10a formed on one yoke 12 so as to open and connect to the main yoke chamber 9 on one yoke 12 side, and one end connected to the passage 10a. A passage 10 b formed in a semi-annular shape on the yoke 13 side, and one end connected to the semi-circular passage 10 b and the other end displaced, for example, by 180 ° with respect to the opening position of the passage 10 a on the yoke 12 side. A passage 10c formed on the yoke 13 side so as to open and connect to the auxiliary liquid chamber 8 is constituted.

  Then, both ends of the annular space formed between the ring portion 7B and the electromagnet 11 in the piston-like partition 7 in the displacement direction of the piston-like partition 7 are sealed by annular elastic rubbers 16 and 16, respectively. The MR fluid 15 is hermetically sealed in the annular gap, and the piston-like partition 7 is elastically supported by the annular elastic rubbers 16 at both ends so as to be displaceable in the a-b direction. The MR fluid 15 is a Bingham fluid obtained by dispersing ferromagnetic metal fine particles having a particle diameter of about 1 to 10 μm in a high-concentration suspension, has an operating temperature range of −40 to 150 ° C., and has a strong magnetic field. The viscosity changes depending on the size of the fluid, and is called a magnetorheological fluid or a magnetorheological fluid.

  In the liquid-filled vibration absorbing device having the above-described configuration, under a condition in which vibration in a low frequency range acts, an electromagnet switch (not shown) is turned on to apply a constant applied current to the electromagnet 11, thereby causing the magnetic path 14 to pass through. The strength of the formed magnetic field increases, and the viscosity of the MR fluid 15 increases accordingly. As shown by the dotted line in FIG. 2A, the rigidity of the piston-like partition wall 7, that is, the dynamic spring constant is reduced. growing. As a result, the piston-like partition 7 is almost fixed, and the sealed liquid in the main liquid chamber 9 flows through the buffer orifice 10 to the sub liquid chamber 8 to absorb fluctuations in the liquid pressure in the main liquid chamber 9. As shown by the dotted line in FIG. 2B, a large attenuation coefficient is obtained in a low frequency region.

  On the other hand, under the condition where the vibration in the high frequency region acts, the magnetic field strength is reduced by turning off the electromagnet switch and stopping the energization to the electromagnet 11, and the viscosity of the MR fluid 15 is reduced accordingly. Thus, as shown by the solid line in FIG. 2 (a), the rigidity of the piston-shaped partition wall 7, that is, the dynamic spring constant becomes smaller than when energized. As a result, the piston-like partition 7 can be freely displaced, and the damping coefficient in the low frequency region becomes smaller as compared with the case where the electromagnet switch is ON, as shown by the solid line in FIG. Since the bulk elastic moduli of the sub two liquid chambers 9 and 8 are changed with good responsiveness, it is possible to exert a sufficiently large damping effect on vibration in a high frequency region.

Further, by changing the magnetic field strength by increasing or decreasing the current applied to the electromagnet 11 when the electromagnet switch is ON, the viscosity of the MR fluid 15 fluctuates and the difference in the thickness in FIG. As shown by a plurality of solid lines, the peak value of the dynamic spring constant of the piston-like partition wall 7 and the frequency of the peak value can be changed, whereby the plurality of solid lines having different thicknesses in FIG. Thus, the peak frequency of the damping coefficient in the low frequency region is varied, and accordingly, when the electromagnet switch is OFF, that is, the bulk modulus of the two main and sub liquid chambers 9 and 8 in the high frequency region is reduced. By arbitrarily changing, it is possible to exert a large damping effect on vibration in a wide frequency range in a high frequency range.
[Example 2]

FIG. 4 shows a vertical cross-sectional structure of a liquid-filled vibration absorbing device according to a second embodiment. The second embodiment differs from the first embodiment in that an orifice 10 is formed in a main body 7A of a piston-like partition wall 7. Only the other components are the same as those of the first embodiment, and the same reference numerals are given to the corresponding portions, and detailed description of those components is omitted.
[Examples 3 and 4]

FIG. 5 shows a longitudinal sectional structure of a liquid-filled vibration absorbing device of the third embodiment, and FIG. 6 shows a longitudinal sectional structure of a liquid-filled vibration absorbing device of the fourth embodiment. In the annular gap formed between the ring portion 7B and the electromagnet 11, the annular elastic rubber 16, 16 is formed only in the portion where the magnetic path 14 is formed near one end of the piston-like partition wall 7 in the displacement direction (ab). The first embodiment differs from the first embodiment in that the MR fluid 15 is interposed in a hermetically sealed state via the second embodiment 16, and other configurations are the same as those in the first embodiment. Detailed description of the structure is omitted. In Examples 3 and 4, the leakage magnetic flux is reduced and the magnetic flux can be formed more efficiently. In particular, as in Embodiment 4 shown in FIG. 6, the outer peripheral edge 7e of the main body 7A and the inner peripheral edge 12e of the yoke 12 in the piston-like partition 7 are both sharpened and opposed to each other to reduce the gap. The electromagnetic force can be increased relative to the applied current.
[Examples 5 and 6]

FIG. 7 shows a longitudinal sectional structure of the liquid-filled vibration absorbing device of the fifth embodiment, and FIG. 8 shows a longitudinal sectional structure of the liquid-filled vibration absorbing device of the sixth embodiment. , 16 are formed in a substantially mountain-shaped cross-sectional shape so as to protrude outward from the magnetic path 14, so that the elastic rubbers 16, 16 do not interfere with the magnetic flux. The sixth embodiment differs from the first embodiment in that the electromagnets 11 are additionally arranged in an inner and outer double, and the other configuration is the same as that of the first embodiment. The detailed description of those structures is omitted.
[Examples 7 to 9]

9 is a longitudinal sectional view of the liquid-filled vibration absorbing device of the seventh embodiment, FIG. 10 is a longitudinal sectional view of the liquid-filled vibration absorbing device of the eighth embodiment, and FIG. In the seventh, eighth and ninth embodiments, a protruding portion 7b is integrally formed outwardly from an intermediate position of the ring portion 7B in the piston-like partition wall 7 and the inner circumferences of the yokes 12 and 13 are shown. The extension yoke portions 12a and 13a are integrally formed so as to protrude from the end portion toward the protruding portion 7b, so that a plurality of magnetic paths 14 are formed to further increase or decrease the viscosity of the MR fluid 15 due to the magnitude of the magnetic field strength. Embodiment 8 differs from Embodiment 1 in that it can be performed efficiently. In Embodiment 8, in addition to this, an orifice 17 for restricting the flow of the MR fluid 15 is provided in the protruding portion 7b of the ring portion 7B to provide a high frequency region. Piston-shaped partition 7 The embodiment differs from the first embodiment in that the displacement speed is appropriately controlled. In the ninth embodiment, in addition, the orifice 17 provided on the protruding portion 7b of the ring portion 7B is displaced in the displacement direction (ab). The embodiment is different from the first embodiment also in that it is inclined with respect to the flow direction of the MR fluid 15 to provide resistance to the flow of the MR fluid 15, and the other configuration is the same as that of the first embodiment. The detailed description of those structures is omitted.
[Example 10]

FIG. 12 shows a longitudinal sectional structure of a liquid-filled vibration absorbing device according to the tenth embodiment. In the tenth embodiment, the piston-like partition wall 7 includes only a disk-shaped main body 7A. The end portion is different from the first embodiment in that the piston-like partition wall 7 is configured to be displaceable in the a-b direction by holding the MR fluid 15 with a rubber tube-like elastic body 18 hermetically sealed. Since this embodiment is the same as the first embodiment, the same reference numerals are given to the corresponding portions, and the detailed description of the structures is omitted.
[Example 11]

  FIG. 13 shows a vertical cross-sectional structure of the liquid-filled vibration absorbing device according to the eleventh embodiment. In the eleventh embodiment, the ring portion 7B of the piston-like partition wall 7 is attached and fixed to the inner peripheral ends of the yokes 12, 13. The first embodiment differs from the first embodiment in that the MR fluid 15 is formed between the non-magnetic annular elastic member 19 and the electromagnet 11 and housed and held in an annular gap in which the MR fluid 15 is sealed so as to be displaceable in the a-b direction. Differences and other configurations are the same as those of the first embodiment. Therefore, corresponding portions are denoted by the same reference numerals, and detailed description of those structures is omitted.

  In any of the liquid-filled vibration absorbing devices of the above-described Embodiments 2 to 11, the piston-shaped partition wall 7 is fixed and the liquid in the main liquid chamber 9 is filled with the buffer orifice 10 against vibration in the low frequency range. And flows to the sub liquid chamber 8 side to absorb the fluctuation of the liquid pressure in the main liquid chamber 9 to obtain a large damping coefficient. With the decrease, the dynamic spring constant of the piston-like partition 7 becomes small and becomes freely displaceable, and the bulk modulus of the two main and sub-liquid chambers 9 and 8 is changed with good responsiveness to exhibit a sufficiently large damping effect. As in the case of the first embodiment, it is possible to exhibit the substantially same vibration damping action as in the first embodiment.

  In each of the above embodiments, the piston-shaped partition wall 7 is circular, and accordingly, the electromagnet 11 is formed in an annular shape, and the MR fluid 15 is also arranged and interposed in an annular shape. In the case where the partition wall 7 has an elliptical shape or a rectangular shape, the shape of the electromagnet 11 and the interposed shape of the MR fluid 15 may be an elliptical annular shape or a rectangular annular shape.

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. (A) is a characteristic diagram showing the correlation between the dynamic spring constant and the frequency when the electromagnet switch is turned ON / OFF, and (b) is a characteristic diagram showing the correlation between the damping coefficient and the frequency at that time. (A) is a characteristic diagram showing the correlation between the dynamic spring constant and the frequency when the applied current is increased or decreased by turning on the electromagnet switch, and (b) is a characteristic diagram showing the correlation between the damping coefficient and the frequency at that time. is there. 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. FIG. 13 is a longitudinal sectional structural view of a liquid-filled vibration absorbing device according to a seventh embodiment of the present invention. FIG. 14 is a longitudinal sectional view of a liquid-filled vibration absorbing device according to an eighth embodiment of the present invention. FIG. 16 is a longitudinal sectional view of a liquid-filled vibration absorbing device according to a ninth embodiment of the present invention. FIG. 16 is a longitudinal sectional view of a liquid-filled vibration absorbing device according to a tenth embodiment of the present invention. FIG. 21 is a vertical sectional view of a liquid-filled vibration absorbing device according to an eleventh embodiment of the present invention.

Explanation of reference numerals

3 Body Elastic Rubber 5 Diaphragm 6 Hollow Body 7 Piston Partition 7A Body 7B Ring 8 Sub-Liquid Chamber 9 Main Fluid Chamber 10 Orifice 11 Electromagnet 12, 13 Yoke 14 Magnetic Path 15 MR Fluid

Claims (3)

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 piston-like member made of a ferromagnetic material that can be displaced in a direction in which the volumes of the main and sub two liquid chambers are changed,
An electromagnet is annularly arranged concentrically with the piston-like partition so as to constitute a part of the main body, on an outer peripheral portion of the piston-like partition,
Between the annular electromagnet and the piston-shaped partition, ferromagnetic metal fine particles are dispersed in a liquid, and an MR fluid whose viscosity changes according to the magnitude of the magnetic field strength is interposed in a sealed state. Liquid-enclosed vibration absorber.   The piston-shaped partition wall includes a main body made of a nonmagnetic or weak magnetic material, and a ring made of a ferromagnetic material forming a part of a magnetic path together with a yoke connected to both poles of the electromagnet. The liquid-filled vibration absorbing device according to claim 1. 3. The liquid-filled vibration absorbing device according to claim 1, wherein the MR fluid is annularly arranged and interposed on an outer peripheral portion of the piston-shaped partition wall.

Images