JPH0642575A - Fluid seal type vibration proof device - Google Patents

Abstract

PURPOSE:To provide a fluid seal type vibration proof device where the efficiency of the magnetic circuit is improved, the size of a permanent magnet is reduced, a vibration proof device is downsized, and the liquid pressure control of a fluid chamber can be easily and effectively executed by effectively suppressing the distortion of the vibrating plate affected by the driving force. CONSTITUTION:A cylindrical permanent magnet 50 whose inner and outer circumferential parts are magnetic pole parts is arranged at the back of a vibrating plate 27 consisting a part of a wall part of the fluid chamber 32, an inner side yoke 58 which is located on the inner side of a magnet 50 and formes an annular gap part 60 with the specified spacing between the magnet and the inner circumferential surface of the magnet 50, and an outer side yoke 52 mounted on the outer circumferential part of the magnet 50 is connected to the inner side yoke 58 to form the magnetic path. On the other hand, a ring-shaped coil 66 extending in the circumferential direction along the gap part 60 is arranged in a displaceable manner, the coil 66 is connected to the vibrating plate 27, and the vibrating plate 27 is excited through electrification to the coil 66.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fluid filled type vibration damping device, and in particular, it is a fluid filled type which controls switching of vibration damping characteristics by vibrating a part of a wall of a fluid chamber to control internal pressure. Type vibration damping device.

[0002]

2. Description of the Related Art Conventionally, as a type of a vibration isolation device interposed between members constituting a vibration transmission system, a first support fitting attached to each one of the vibration isolation connected or supported members, respectively. A vibration isolation device is known in which a second support metal fitting is elastically connected by a rubber elastic body interposed between the two metal fittings. For example, an automobile engine mount, a suspension bush, etc. Has been used as.

Further, in recent years, as one means for realizing higher vibration isolation characteristics, a part of the wall portion of the anti-vibration device is made of a rubber elastic body, and a predetermined inside is provided. By providing a fluid chamber containing non-compressible fluid, and controlling the internal pressure of the fluid chamber caused by vibration input, the vibration isolation characteristics are switched and controlled according to the input vibration, etc. Various formula structures have been proposed.

For example, in JP-A-59-1828, JP-A-59-1829, and JP-A-3-73741, a part of the wall portion of the fluid chamber is constituted by a diaphragm. A method has been proposed in which the internal pressure of the fluid chamber is controlled by vibrating the vibration plate with an electromagnetic force, and the vibration control characteristics are switched and controlled according to input vibration or the like.

However, in each of the fluid filled type vibration damping devices having the conventional structure disclosed in those publications, the permanent magnet and the coil are used to generate the electromagnetic force for driving the diaphragm. However, since the magnetic path formed by the permanent magnet is an open magnetic path, it is not possible to efficiently secure the magnetic flux density in which the coil is arranged. When inputting vibration in the middle to low frequency range, it is difficult to secure sufficient driving force for the diaphragm, and effective internal pressure control of the fluid chamber becomes difficult, and practically satisfactory vibration isolation characteristics cannot be obtained. There was a problem.

Further, since the magnetic path formed by the permanent magnets is in the form of an open magnetic path, it is not possible to form a region where the magnetic flux density is substantially constant, and the diaphragm is driven. When it is displaced, the magnetic flux density exerted on the coil will change significantly, which makes the driving force exerted on the diaphragm unstable, which inevitably causes distortion in the internal pressure control of the fluid chamber. There is also a problem in that the desired anti-vibration characteristics cannot be obtained sufficiently.

[0007]

The present invention has been made in view of the above circumstances, and a problem to be solved is to drive a diaphragm that constitutes a part of a wall portion of a fluid chamber. The electromagnetic drive mechanism has been improved to improve the efficiency of the magnetic circuit, reduce the size of the permanent magnet, and thus reduce the size of the anti-vibration device, and the distortion of the driving force exerted on the diaphragm is effective. It is an object of the present invention to provide a fluid-filled type vibration damping device that can be effectively suppressed and can easily and effectively control the hydraulic pressure of a fluid chamber.

[0008]

In order to solve such a problem, the present invention provides a rubber in which a first support fitting and a second support fitting which are arranged at a predetermined distance from each other are interposed therebetween. In a fluid filled type vibration damping device comprising a fluid chamber in which a predetermined non-compressible fluid is sealed inside, which is connected by an elastic body, and which constitutes a part of a wall portion by the rubber elastic body,
A part of the wall of the fluid chamber is composed of a displaceable diaphragm, and a cylindrical permanent magnet having an inner peripheral part and an outer peripheral part as magnetic pole parts is disposed behind the diaphragm, An inner yoke, which is located inside the permanent magnet and forms an annular gap portion having a predetermined gap with the inner peripheral surface of the permanent magnet, is arranged, and an outer yoke attached to the outer peripheral portion of the permanent magnet. Is connected to the inner yoke to form a magnetic path, and a ring-shaped coil extending in the circumferential direction along the gap portion is displaceably arranged, and the coil is connected to the diaphragm.
The present invention is characterized in that the diaphragm is vibrated by energizing the coil.

[0009]

By the way, in the fluid filled type vibration damping device having the structure according to the present invention, the area where the coil is arranged has a diameter on the magnetic path formed in the closed magnetic path form. Direction, the magnetic flux of the permanent magnet changes from the gap formed between the inner peripheral surface that is one of the magnetic poles of the cylindrical permanent magnet and the facing surface of the inner yoke. Leakage can be effectively suppressed, and the magnetic flux density in such a region can be improved and uniformed advantageously, and moreover, the inner peripheral portion and the outer peripheral portion are made into magnetic pole portions by being magnetized in the radial direction. Since a cylindrical permanent magnet is used and a magnetic path is formed inside the permanent magnet, the effective cross-sectional area of the permanent magnet can be set large, and the generated magnetic force can be advantageously obtained, and at the same time, the permanent magnet can be obtained. The magnetic flux of Accordingly, it is to become the effect of improving the magnetic flux density on the magnetic path is advantageously exhibited.

As a synergistic effect thereof, the improvement and uniformization of the magnetic flux density in the gap portion can be achieved very effectively, and as a result, a large magnetic flux density is exerted on the coil. As a result, a large driving force can be exerted on the diaphragm when the coil is energized, and even when the coil is displaced, a change in the magnetic flux density exerted on it can be prevented, and a stable driving force can be exerted. Therefore, in the fluid filled type vibration damping device according to the present invention, it is possible to vibrate the vibrating plate with a sufficient driving force and stably, and the control thereof is easy. The anti-vibration properties that are achieved can be exhibited highly and stably.

Moreover, by using the cylindrical permanent magnet magnetized in the radial direction, the annular gap portion is arranged so as to arrange the ring-shaped coil by utilizing the inner peripheral surface which is one of the magnetic pole portions. Therefore, the number of components of the yoke for forming such a gap portion can be reduced, the magnetic circuit can be simplified, and the efficiency of the magnetic circuit can be improved. Thus, the size of the permanent magnet can be advantageously reduced, which can effectively contribute to downsizing of the vibration isolator.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS In order to clarify the present invention more specifically, representative embodiments of the present invention will be described in detail with reference to the drawings.

First, FIG. 1 shows an automobile engine mount having a structure according to the present invention. In this figure, 10 is a first support metal fitting, and 12 is a second support metal fitting, which are arranged to face each other with a predetermined distance therebetween, and a rubber elastic body 14 interposed between them.
They are elastically connected to each other. Then, in such an engine mount, one of the first support fitting 10 and the second support fitting 12 is attached to the power unit side or the body side, so that the power unit can be supported in a vibration-proof manner with respect to the body. It is like this.

More specifically, the first support fitting 10 is
An upper metal fitting 16 and a lower metal fitting 18, each of which has a substantially bottomed cylindrical shape and are provided with outer flange portions 20 and 22 on the peripheral edges of the openings, are overlapped with each other on their opening sides, and both outer flange portions 20 and 22 are formed. It is configured by bolt connection. A mounting bolt 21 is erected on the bottom wall portion of the upper metal fitting 16 so as to project outward, and the first supporting metal fitting 10 is mounted on the power unit side or the body side by the mounting bolt 21. It is designed to be used.

Further, inside the first support fitting 10, between the upper fitting 16 and the lower fitting 18, the recesses 23 and 25 of the fittings 16 and 18 form a void of a predetermined size. ing. Then, in this space, a flexible film 24 having a substantially thin disk shape that divides the space into two is formed.
The flexible membrane 24 is accommodated and arranged, and the flexible membrane 24 is attached by sandwiching the outer peripheral edge portion between the outer flange portions 20 and 22 of the upper metal fitting 16 and the lower metal fitting 18. That is, due to the flexible film 24, such a space is prevented
It is fluid-tightly divided into the recess 23 side of 6 and the recess 25 side of the lower metal fitting 18.

On the other hand, the second support fitting 12 is in the shape of an annular block having a substantially large diameter, and is opposed to the lower fitting 18 of the first support fitting 10 at a predetermined distance in the axial direction. It has been confused. And these first support metal fittings 10
A rubber elastic body 14 is interposed between the second metal fitting 12 and the second support metal fitting 12, and the rubber elastic body 14 is used to connect both metal fittings 10,
12 are elastically connected. The rubber elastic body 14 has a tapered cylindrical shape or a truncated cone shape, and has a bottom wall portion of the lower metal fitting 18 of the first support metal fitting 10 with respect to the opening end surface on the small diameter side. While the outer peripheral surface is fixed, the axial end surface of the second support fitting 12 is fixed to the opening end surface on the large diameter side. That is, the rubber elastic body 14 is formed as an integrally vulcanized molded product having the lower metal fitting 18 and the second support metal fitting 12.

The rubber elastic body 14 connects the first support metal fitting 10 and the second support metal fitting 12 so that the inner hole of the second support metal fitting 12 is passed between them. A recess 26 that opens to the outside is formed.

That is, as is apparent from FIG. 1, the opening 26 on the small diameter side of the tapered rubber elastic body 14 is closed by the first support fitting 10, so that the recess 26 is formed. Is formed in the rubber elastic body 14,
The annular second support fitting 12 is attached to the large-diameter side opening of the rubber elastic body 14,
The recess 26 is connected to the inner hole of the second support fitting 12.

Further, inside the second support fitting 12,
A diaphragm 27 having a substantially thin disk shape is disposed at the opening of the recess 26. At the outer peripheral edge of the vibrating plate 27, an annular plate-shaped support rubber 2 spreading outward in the radial direction is formed.
A ring-shaped plate-shaped mounting ring 30 is integrally mounted via 8 and the mounting plate 30 is bolted to the second support fitting 12, so that the vibration plate 27 is It is adapted to be attached to the second support fitting 12. Therefore, the diaphragm 27 is displaceably attached to the second support fitting 12 based on the elastic deformation of the support rubber 28.

By mounting the vibrating plate 27 on the second support fitting 12, the opening of the recess 26 is fluid-tightly covered. Then, there is formed a pressure receiving chamber 32 in which a predetermined incompressible fluid is sealed. As the enclosed fluid, for example, water, alkylene glycol, polyalkylene glycol, silicone oil, etc. are preferably used.

That is, in the pressure receiving chamber 32, a part of the wall portion is constituted by the rubber elastic body 14, and the vibration input between the first support fitting 10 and the second support fitting 12 is performed. At times, fluctuations in the internal pressure are caused based on the elastic deformation of the rubber elastic body 14.
As is clear from this, in this embodiment, the pressure receiving chamber 32 constitutes a fluid chamber.

On the other hand, the same incompressible fluid as the pressure receiving chamber 32 is sealed in the recess 25 side of the lower metal fitting 18 among the voids formed inside the first support metal fitting 10. As a result, the recess 25 of the lower metal fitting 18 forms an equilibrium chamber 34 in which the volume change is easily allowed due to the deformation of the flexible film 24. The space on the side of the recess 23 of the upper metal fitting 16 that is located on the opposite side of the equilibrium chamber 34 with the flexible film 24 sandwiched therebetween serves as an air chamber 36 that allows deformation of the flexible film 24. There is.

Furthermore, the pressure receiving chamber 32 and the equilibrium chamber 34
On the bottom wall portion of the lower metal fitting 18 that forms the partition wall for partitioning the and the disk metal fittings 38 are superposed and fixed by bolts.
The disc metal fitting 38 is provided with a circumferential groove 40 extending in the circumferential direction on the overlapping surface with the lower metal fitting 18. As a result, when they are stacked on the lower metal fitting 18, between the overlapping surfaces of the disk metal fitting 38 and the lower metal fitting 18,
It extends in a predetermined length in the circumferential direction, and both ends in the circumferential direction are passed through communication holes provided in the lower metal fitting 18 and the disk metal fitting 38,
An orifice passage 46 is formed so as to communicate with the pressure receiving chamber 32 and the equilibrium chamber 34.

When an internal pressure fluctuation is induced in the pressure receiving chamber 32 at the time of vibration input, between the pressure receiving chamber 32 and the equilibrium chamber 34,
By causing the fluid to flow through the orifice passage 46, a predetermined vibration isolation effect is exhibited based on the fluid flow action or resonance action. In the present embodiment, the length and cutoff of the orifice passage 46 are adjusted so that a high damping effect can be exerted when a low-frequency large-amplitude vibration such as a shake is input based on the resonance action of the fluid that is made to flow through the orifice passage 46. Area etc. are tuned.

On the other hand, an electromagnetic drive means 48 according to the present invention is mounted on the second support fitting 12 and is located behind the vibrating plate 27 which constitutes a part of the wall of the pressure receiving chamber 32. Is provided.

The electromagnetic drive means 48 has a cylindrical permanent magnet 50 having a predetermined length. The permanent magnet 50 is magnetized in the radial direction so that the inner peripheral portion is one magnetic pole portion and the outer peripheral portion is the other magnetic pole portion, and the outer peripheral portion on the other magnetic pole side has a bottomed cylindrical shape. It is attached to the outer yoke 52 having a shape. That is, the outer yoke 52 has an outer flange 54 provided in its opening.
In the above, the second support fitting 12 is bolted to the second support fitting 12, while the permanent magnet 50 is attached to the stepped portion on the inner peripheral surface of the opening and is fixed by the holding fitting 56. The permanent magnet 50 is held by the outer yoke 52.

Then, the outer yoke 5 having a bottomed cylindrical shape.
A cylindrical inner yoke 58 is concentrically and integrally erected on the inner side of the bottom of the second magnet so as to form a gap portion 60 having a predetermined gap with the inner peripheral surface of the permanent magnet 50. ing. The outer yoke 52 and the inner yoke 58 are both made of a ferromagnetic material such as iron, thereby forming a magnetic path having a substantially closed magnetic path, and An annular or cylindrical gap portion 60 continuous in the circumferential direction is formed between the peripheral surface and the outer peripheral surface of the inner yoke 58.

On the other hand, a bottomed cylindrical bobbin 62 made of a non-magnetic material such as synthetic resin or aluminum is fixed to the diaphragm 27 at its bottom portion with bolts and nuts. A cylindrical wall portion 64 of the bobbin 62 is axially movable in a gap portion 60 formed between the inner peripheral surface of the permanent magnet 50 and the outer peripheral surface of the inner yoke 58. It is inserted and arranged,
Further, an annular or cylindrical coil 66 is fixed to the outer peripheral surface of the cylindrical wall portion 64, whereby the coil 66 and the bobbin 62 are arranged in the gap portion 60.
The permanent magnet 50 and the outer yoke 52 can be integrally displaced. The coil 66 attached to the bobbin 62 is connected to the coil 68 from the outside through the lead 68.
A predetermined current is made to flow.

Therefore, in the engine mount having the above-described structure, by applying an alternating current to the coil 66, an electromagnetic force (Lorentz force) according to Fleming's left-hand rule is generated in the coil 66, Thus, a driving force proportional to the current is exerted on the diaphragm 27 via the bobbin 62 having the coil 66 attached thereto. Then, the energization of the coil 66 is controlled, and the internal pressure of the pressure receiving chamber 32 can be controlled by vibrating the diaphragm 27 in accordance with the internal pressure variation of the pressure receiving chamber 32 caused by the input vibration. Thus, it becomes possible to appropriately change the vibration damping characteristics of the mount.

Specifically, for example, when a low frequency vibration is input, the diaphragm 27 is vibrated in the same phase as the input vibration,
By positively generating the internal pressure of the pressure receiving chamber 32 and increasing the flow amount of the fluid that is made to flow through the orifice passage 46, high damping characteristics can be exhibited, and the input of medium to high frequency vibrations can be achieved. At times, the vibration plate 27 is vibrated in a phase opposite to the input vibration to absorb or reduce the internal pressure of the pressure receiving chamber 32, whereby the low dynamic spring characteristic can be exhibited.

Particularly, in the engine mount having the above-described structure, in the electromagnetic drive means 48, the gap portion 60 in which the coil 66 is arranged is formed on the magnetic path formed in the closed magnetic path form, and the magnetic flux Leakage can be effectively suppressed, and the magnetic flux density in the gap portion 60 can be advantageously secured.

Moreover, as the permanent magnet 50, an annular permanent magnet which is magnetized in the radial direction and whose inner peripheral portion and outer peripheral portion are magnetic pole portions is used, and between the inner peripheral surface and the inner yoke 58. Since the gap portion 60 is formed in the coil 66, the magnetic force of the permanent magnet 50 can be made to act on the coil 66 with the largest possible area, whereby the generated magnetic force, and thus the magnetic flux in the gap portion 60. The density can be secured more advantageously.

In addition, since the magnetic path is formed inside by using the annular permanent magnet 50, the magnetic flux of the permanent magnet is collected inside, and it is advantageous to improve the magnetic flux density on the magnetic path. This can be achieved, whereby a further improvement of the magnetic flux density in the gap portion 60 provided on such a magnetic path can be achieved.

As a result, for the coil 66,
A large magnetic flux density can be exerted, and a large electromagnetic force is generated when the coil 66 is energized, so that a sufficient driving force for the diaphragm 27 can be ensured and the pressure receiving chamber 32 can be effectively used. Since the internal pressure can be controlled, the intended vibration damping property can be effectively exhibited.

Further, as described above, the magnetic flux density in the gap portion 60 can be ensured extremely efficiently. As a result, in the engine mount as described above, the permanent magnet 50 does not generate so much magnetic force and is inexpensive. It is also possible to adopt a magnet, which has an advantage that the cost can be reduced, and the size itself of the permanent magnet 50 can be reduced to achieve the weight reduction.

Further, in the engine mount having the above-described structure, the region (gap portion 60) in which the coil 66 is arranged utilizes the inner peripheral portion that constitutes one magnetic pole portion of the permanent magnet 50, and Since the magnetic flux density is directly formed between the peripheral surface and the inner yoke 58 facing the peripheral surface to form a closed magnetic path, it is possible to effectively achieve the uniformization of the magnetic flux density in such a region, and thus the coil 66.
Even when is displaced, the magnetic flux density exerted on the coil 66, and consequently the generated electromagnetic force, can be maintained at a substantially constant value.

Therefore, since it becomes possible to stably obtain an electromagnetic force substantially proportional to the amount of current passing through the coil 66, it becomes easy to control the vibration of the coil 66, and hence the diaphragm 27, and the distortion is generated. It is possible to effectively prevent the occurrence of, and thereby, it is possible to control the internal pressure of the pressure receiving chamber 32 with high accuracy, and the desired vibration damping characteristics can be exhibited more highly and stably. is there. Moreover, the vibration control of the diaphragm 27 can be performed with high accuracy, and the distortion of the pulsation (internal pressure fluctuation) generated in the pressure receiving chamber 32 is reduced or prevented. Therefore, the problem that the vibration in the region other than the target frequency is amplified is not a problem.

FIG. 2 shows another embodiment of the present invention, in which the present invention is applied to a so-called bush type engine mount.

Here, in the engine mount, an inner tubular metal member 70 and an outer tubular metal member 72, which are arranged at a predetermined distance in a radial direction from each other and are eccentric by a predetermined amount, are interposed between the rubber members. The elastic body 74 is provided with a mount main body 76 configured by being elastically connected to each other, and the mount main body 76 is integrally assembled with a bracket 78. . In such an engine mount, the inner tubular metal fitting 70 of the mount body 76 is attached to either the body side or the power unit side, and the outer tubular metal fitting 72 is attached via the bracket 78 to the body side and the power unit. The power unit is attached to either of the other sides so as to support the power unit against vibrations with respect to the body.

In such a mounted state, in the mount body 76, the rubber elastic body 74 is deformed by the weight of the power unit exerted between the inner and outer tubular metal fittings 70 and 72, so that the inner and outer tubular metal fittings 70, 72 is positioned substantially coaxially. Further, under such a mounted state, the engine mount includes inner and outer tubular metal fittings 70, 72.
The main vibration to be isolated is input in the eccentric direction (vertical direction in FIG. 2).

By the way, such a structure of the mount body 76 is well known, and is disclosed in, for example, Japanese Patent Laid-Open No. 1-1538.
Since it is obvious from reference to the publication No. 31, etc., the detailed description will be omitted here, and the structure will be briefly described.

That is, in such a mount main body 76, the pressure receiving chamber 80 formed by the rubber elastic body 74 and the outer tubular metal fitting 72 includes the deformable diaphragm 82 formed of a thin rubber film and the outer tubular metal fitting 72. Between the pressure-receiving chamber 80 and the equilibrium chamber 84, which are made to communicate with the equilibrium chamber 84 formed between them through the orifice 86 having a predetermined length and cross-sectional area. Are allowed to flow to each other through the orifice 86.

Further, as is well known, an umbrella metal fitting 88 is arranged in the pressure receiving chamber 80, and at its leg portion,
It is fixed to the inner cylinder metal fitting 70.
0 and the umbrella metal fitting 88 are moved relative to the outer tubular metal fitting 72 (in the vertical direction in the figure), so that the umbrella metal fitting 88 is positioned in an annular narrow portion formed around the umbrella metal fitting 88. As is well known, a predetermined vibration damping effect can be exhibited based on the flow action or resonance action of the fluid.

The mount body 76 having such a structure is integrally assembled with the bracket 78. The bracket 78 has a mounting portion for fixing to the body side or the power unit side. 90
However, a circular mounting hole 92 is formed so as to project outwardly and penetrate through the central portion thereof, and the mount main body 76 is press-fitted and fixed in the mounting hole 92. It is supposed to be assembled by.

The mounting hole 9 is formed in the bracket 78.
The through hole 9 extending through the peripheral wall portion is formed in the portion of the mount body 76 mounted on the second body, which is located outside the pressure receiving chamber 80.
4 is provided, and a through hole 96 is provided in the outer tubular metal fitting 72 of the mount body 76 located on the inner opening of the through hole 94. Thereby, such a through hole 9
4 is the pressure receiving chamber 8 of the mount body 76 through the through hole 96.
It is connected to 0.

On the other hand, the outer opening of the through hole 94 has a diameter increased by a predetermined dimension, and a diaphragm 98 having a substantially disc shape is disposed therein. An attachment ring 102 is attached to the outer peripheral edge of the vibration plate 98 via a disc-shaped support rubber 100 that covers the surface on the mount body 76 side and spreads outward in the radial direction. Since 102 is bolted to the bracket 78,
A diaphragm 98 is attached to the bracket 78. That is, the vibration plate 98 is displaceably attached to the bracket 78 based on the elastic deformation of the support rubber 100.

By attaching the vibrating plate 98, the opening of the through hole 94 provided in the bracket 78 is covered in a fluid-tight manner, whereby a predetermined incompressible fluid is sealed inside, and A sub liquid chamber 104 is formed in communication with the pressure receiving chamber 80. Therefore, in the present embodiment, the pressure receiving chamber 80 and the sub liquid chamber 104 constitute a fluid chamber in which fluctuations in the internal pressure are induced at the time of vibration input.

The through hole 9 that forms the sub liquid chamber 104 is formed.
4, a cylindrical seal rubber sleeve 108 is inserted and arranged on the inner peripheral surface of the mounting member 4, and an annular plate-shaped pressing metal fitting 110 and a mount body 7 which are bolted to the bracket 78.
A connecting portion between the sub liquid chamber 104 and the pressure receiving chamber 80 is sealed by being pinched in the axial direction between the outer tubular metal member 72 and the outer tubular metal member 72.

Then, the electromagnetic drive means 112 according to the present invention is mounted on the bracket 78 so as to be positioned behind (above in the figure) a diaphragm 98 which constitutes a part of the wall portion of the sub liquid chamber 104. Has been done.

Since this electromagnetic drive means 112 has the same structure as the electromagnetic drive means 48 in the above-mentioned embodiment, in the figure, the members and parts corresponding to those in the above-mentioned embodiment are respectively executed as described above. The detailed description will be omitted by giving the same reference numerals to the examples.

In the electromagnetic drive means 112 of the present embodiment, the inner yoke 114 has a cylindrical shape, and the inner yoke 114 has a bottom inner surface with respect to the outer yoke 52 having a bottomed cylindrical shape. It is different from the above-mentioned embodiment in that it is bolted to.

Therefore, according to the structure of such an embodiment, the present invention can be advantageously applied to a cylindrical structure, that is, a so-called bush type engine mount, whereby the same as in the above embodiments. Such effects can be effectively exhibited.

Although the representative embodiments of the present invention have been described in detail above, they are literal examples and the present invention should not be construed as being limited to such specific examples. Needless to say, the present invention is carried out in a mode in which various changes, modifications, improvements, etc. are added based on the knowledge of those skilled in the art, and such an embodiment is not departing from the spirit of the present invention. It should be understood that all are included within the scope of the present invention.

For example, in each of the above-described embodiments, equilibrium chambers 34, 84 are provided which communicate with the fluid chambers (pressure receiving chamber 32, pressure receiving chamber 80 and sub liquid chamber 104) through orifice passages 46, 86. However, the orifice passage and the equilibrium chamber are not necessarily provided.

Even in the vibration isolator having neither the orifice passage nor the equilibrium chamber, by controlling the internal pressure of the fluid chamber, the above-described effect based on the switching control of the vibration isolation characteristic can be effectively exhibited. Can be done.

Further, the specific structure of the yoke portion for forming the magnetic path including the permanent magnet should not be construed as being limited to that of the above embodiment, and the required shape of the vibration isolator is required. It can be appropriately changed according to the size, size and the like.

Further, in the above-mentioned embodiment, a specific example of the present invention applied to an engine mount for an automobile is shown, but in addition, a body mount, a differential mount, a suspension bush for an automobile, or various devices other than an automobile. It is needless to say that the same can be applied to the vibration isolator in FIG.

[Brief description of drawings]

FIG. 1 is a vertical cross-sectional explanatory view showing an engine mount for an automobile as an embodiment of the present invention.

FIG. 2 is a cross-sectional explanatory view showing an automobile engine mount having a cylindrical structure as another embodiment of the present invention.

[Explanation of symbols]

 10 1st support metal fitting 12 2nd support metal fitting 14,74 Rubber elastic body 27,98 Vibration plate 28,100 Support rubber 32,80 Pressure receiving chamber 48,112 Electromagnetic drive means 50 Permanent magnet 52 Outer yoke 58,114 Inner yoke 60 Gap part 62 Bobbin 64 Cylinder wall part 66 Coil 70 Inner cylinder metal fitting 72 Outer cylinder metal fitting 76 Mount body 78 Bracket 104 Sub liquid chamber

Claims (1)

[Claims] 1. A first supporting metal member and a second supporting metal member, which are arranged at a predetermined distance from each other, are connected by a rubber elastic body interposed therebetween, and a predetermined non-conductive member is internally provided. In a fluid filled type vibration damping device in which a fluid chamber in which a compressive fluid is enclosed is provided by forming a part of the wall portion with such a rubber elastic body, a portion of the wall portion of the fluid chamber can be displaced. A cylindrical permanent magnet having a vibrating plate, the inner peripheral portion and the outer peripheral portion of which are magnetic poles is disposed behind the vibrating plate, and the permanent magnet is located inside the permanent magnet. A magnetic path is formed by arranging an inner yoke that forms an annular gap portion with a predetermined gap between the inner yoke and the inner peripheral surface, and connecting an outer yoke attached to the outer peripheral portion of the permanent magnet to the inner yoke. On the other hand, a ring-shaped coil extending in the circumferential direction along the gap is disposed so as to be displaceable. , Ligated to the coil to the diaphragm,
A fluid-filled type vibration damping device characterized in that the diaphragm is vibrated by energizing the coil.