JPH094670A - Damper - Google Patents

Abstract

PURPOSE: To provide a damper capable of reducing vibration in a short time with the excellent portability. CONSTITUTION: A cylinder 12 provided on the inner peripheral surface with an electrode 20 receives electric viscous fluid 24 into which a piston body 14A of a piston part 14 is sunk, and an O-ring 18 for a seal is mounted to the upper surface of the cylinder 12. The piston body 14A is provided on the outer peripheral surface with an electrode 22 and the piston body 14A is formed on the upper part with a flange 14B to close an opening of the cylinder 12. The viscosity of the electric viscous fluid 24 is instantaneously increased by applying desired voltage to the electrodes 20, 22 so that the damping constant of the damper 10 can be instantaneously enlarged. When the damper 10 is transported for example, a flange part 12C is moved into intimate contact with the flange 14B by the use of a screw. Thus, the interior is completely hermetically enclosed and the flowout of the electric viscouse fluid 24 in the transport or the like can be prevented.

Description

Detailed Description of the Invention

[0001]

The present invention relates to an electron microscope, a precision balance,
Equipped with precision equipment such as minute size / shape / roundness measuring instrument, surface roughness meter, and micro hardness meter, precision machining equipment, etc. to eliminate vibration generated by driving precision equipment and vibration received from the floor etc. The present invention relates to a damper used for a vibration isolation table, etc.

[0002]

2. Description of the Related Art An anti-vibration table equipped with precision equipment and precision processing equipment has extremely low rigidity (0.5 to 0.5 in natural frequency).
5Hz) air springs and multi-stage laminated rubber, etc. are used as support materials, and dampers such as dash pots are provided.
A passive vibration isolator that can provide vibration isolation for extremely small vibrations on the order of microns, and a semi-vibration mechanism that changes the spring characteristics of the vibration isolation mechanism so that it can be used not only for small vibrations but also for vibrations of large amplitude. A VCM (Voice Coil Motor) that provides an active vibration isolation device and a vibration sensor on the surface plate, performs feedback control based on a signal from the sensor, and adds a force having a phase opposite to the vibration to the surface plate to eliminate the vibration. There has been an active vibration isolation device that is provided with an actuator such as an air spring and can perform vibration isolation according to the amplitude of vibration.

Here, in the open type electrorheological fluid damper used in the vibration isolator, a fluid such as oil is stored in a cylinder whose upper end is open, and a rod-shaped piston is simply arranged in this fluid. Has been used.

[0004]

The passive vibration isolation device is
Since the vibration received from the floor surface is insulated, the rigidity of the air spring etc. is extremely small, and the vibration amplitude with which the vibration isolation effect can be obtained is of the order of deci-micron, and the large vibration such as the vibration generated by the drive of the on-board equipment itself. There is almost no damping effect for large vibration amplitude, and it takes a long time for the large vibration that has occurred once to converge to the deci-micron order amplitude and to obtain the vibration isolation effect, and the work efficiency is very high. It was bad for me. Therefore, if the damping constant of the damper is increased in order to damp large vibrations in a short time, the high frequency component of the vibrations will not be effectively damped, and the vibration isolation performance will be deteriorated overall.

In addition, a semi-active vibration isolator has not been satisfactorily used for vibration isolation according to the amplitude of vibration. Vibrations can be converged in a short time, but since an air tank must be provided for each air spring, the installation space is very large and expensive, and the actuator using VCM is responsive. Is excellent, but a large VCM is required to support a surface plate on which a heavy object is placed, and the device is complicated, resulting in a very high price.

On the other hand, in recent years, fluid devices using an electrorheological fluid whose viscosity changes instantaneously when a voltage is applied have been proposed.

For example, Japanese Utility Model Publication No. 1-98938 discloses a lock device using an electrorheological fluid.

This lock device is used for a vibration isolation / vibration / isolation device, and is capable of locking a supported portion on which a precision instrument is placed and which is elastically supported by an air spring. However, in the lock device provided with the seal ring, horizontal vibration may be transmitted through the seal ring.

On the other hand, an open type lock device not provided with a seal ring is inferior in portability because the electrorheological fluid will be spilled if it is greatly shaken or tilted. Further, foreign matter such as dust or dust is likely to enter the electrorheological fluid, and the characteristics of the electrorheological fluid may change due to the entry of the foreign matter, for example, electrical insulation may be deteriorated. If the insulating property of the electrorheological fluid is deteriorated, there is a possibility that electric discharge may occur between the electrodes.

An object of the present invention is to provide a damper capable of solving the above problems in consideration of the above facts.

[0011]

A damper according to a first aspect of the present invention is a damper having an open top for accommodating an electrorheological fluid whose viscosity changes when a voltage is applied, and a piston disposed in the viscous fluid. And a first electrode provided on the cylinder for applying a voltage to the electrorheological fluid,
A second electrode provided on the piston and facing the first electrode to apply a voltage to the electrorheological fluid, and a second electrode connected to the piston, connected to the piston, and closing the opening of the cylinder when not in operation. And a blocking means for blocking the outflow of the electrorheological fluid.

According to a second aspect of the present invention, in the damper according to the first aspect, at least one of the closing means and the cylinder is provided with a seal member made of an elastic body, and when the opening of the cylinder is closed, the other side is closed. The feature is that it closely adheres to and completely seals the cylinder.

According to a third aspect of the present invention, the damper according to the first or second aspect is characterized in that a dust entry preventing means for covering the opening in a non-contact state is provided.

According to a fourth aspect of the present invention, in the damper according to any one of the first to third aspects, a low-rigidity dust intrusion prevention film that seals the inside of the cylinder is provided. There is.

The invention described in claim 5 is the same as claim 1.
The damper according to any one of claims 4 to 4 is characterized in that the damper is provided with positioning means for designating a position where the first electrode and the second electrode face each other.

[0016]

In the damper according to the first aspect of the present invention, one of the cylinder and the piston is connected to an object to be vibrated, such as a surface plate of a vibration isolation table, and the other is connected to a vibration receiving portion such as a floor. To do. By applying a desired voltage between the first electrode and the second electrode and setting the viscosity of the electrorheological fluid to a desired value,
The damping constant of the damper can be instantaneously changed according to the amplitude, and vibration can be suppressed in a short time according to the amplitude. For example, when the amplitude of vibration is large, a voltage is applied to the electrorheological fluid to increase the viscosity, and when the amplitude of vibration is subsequently reduced, the voltage is lowered (or the application of voltage is stopped). By lowering the viscosity of and damping the
Vibration can be suppressed in a short time.

Further, when the damper is transported, that is, when the damper is not operated, the opening of the cylinder is closed by the closing means to prevent the electrorheological fluid from flowing out. On the other hand, when the damper operates, the opening of the cylinder is not closed by the closing means. That is, when the damper is operated, the closing means does not contact the cylinder, so that vibration is not transmitted from the cylinder to the piston or from the piston to the cylinder through the closing means.

According to the damper of the second aspect, when the opening of the cylinder is closed by the closing means, the seal member comes into close contact with the other side to completely seal the inside of the cylinder. As the seal member, oil resistant rubber or the like is preferable.

In the damper according to the third aspect, since the dust entry preventing means for covering the opening in a non-contact state is provided, it is possible to suppress the entry of dust and the like into the electrorheological fluid in the use state. Further, since the dust entry preventing means is not in contact with the cylinder, vibration is not transmitted from the cylinder to the piston or from the piston to the cylinder via the dust entry preventing means. The dust ingress prevention means
It is preferable to extend below the opening of the cylinder to cover the cylinder.

In the damper according to the fourth aspect, by providing the low-rigidity dust intrusion prevention film for sealing the inside of the cylinder, it is possible to completely seal the inside of the cylinder, and to prevent dust and dirt from entering the electrorheological fluid. It is possible to reliably prevent foreign matter from entering. Further, since the dust entry prevention film has extremely low rigidity, vibration is not transmitted from the cylinder to the piston or from the piston to the cylinder through the dust entry prevention film. The dust intrusion prevention film is preferably made of a flexible material such as rubber or synthetic resin and formed in a bellows shape.

Further, in the damper according to the fifth aspect, since the positioning means indicates the position where the first electrode and the second electrode are correctly opposed to each other, the damper should be attached in a correct state to operate properly. Is possible.

[0022]

【Example】

[First Embodiment] A first embodiment of the present invention will be described with reference to FIGS.

As shown in FIG. 1, the damper 10 includes a cylinder 12 made of an insulating material such as synthetic resin and a piston portion 14 also made of an insulating material such as synthetic resin.

The piston portion 14 is integrally formed with a flange 14B as a closing means on an upper portion of a cylindrical piston body 14A having a constant diameter.

On the other hand, the cylinder 12 has a cylindrical portion 12A,
Bottom part 12B closing the lower part of the cylindrical part 12A, cylindrical part 12
A flange portion 12C provided on the upper portion of A is provided.

An annular groove 16 is formed on the upper surface of the cylinder 12, and an O-ring 18 as a sealing member made of an elastic material such as rubber is fitted into the annular groove 16. A part of the O-ring 18 is the cylinder 1.
2 is projected from the upper surface.

The inner wall surface of the cylinder 12 has a cylindrical portion 12
An electrode plate 20 made of a thin metal plate formed in a ring shape is provided in the middle portion in the height direction of A. The inner peripheral surface of the electrode 20 is flush with the inner peripheral surface of the cylindrical portion 12A.

On the other hand, on the outer peripheral surface of the piston portion 14, an electrode plate 22 made of a thin metal plate formed in a ring shape is provided. The outer peripheral surface of the electrode 22 is flush with the outer peripheral surface of the piston body 14A.

An electrorheological fluid 24 is stored in the cylinder 12. The electrorheological fluid 24 is obtained by dispersing and suspending hydrophobic fine particles in electric insulating oil, and when a voltage is applied, the viscosity increases extremely quickly in accordance with the voltage, and
The viscosity reversibly decreases. The viscosity can be changed not only by direct current but also by alternating current, and can be changed from liquid to almost solid state with low power consumption. Electrorheological fluid 24
When a voltage is applied to the particles, the charge in the particles moves due to the voltage, and the particles are polarized to generate an attractive force between the particles.
Since the particles are connected in a bead shape between the electrodes, the viscosity is increased. Such a change in viscosity changes in millisecond units according to the strength of the electric field, the viscosity changes in response to the detection signal from the sensor, and the change in viscosity is constant with respect to temperature change. It can be used for temperatures of ° to +150 °.

As shown in FIGS. 1 and 2, the piston portion 1
The flange 14B of No. 4 is provided with a screw hole 26 for mounting used for connection with a surface plate or the like and a screw hole 28 used for connection with the cylinder 12. A round hole 29 is formed in the flange portion 12C of the cylinder 12 at a position facing the screw hole 28.

By the way, the damper 10 can be used, for example, in a vibration isolation table. As shown in FIG. 3, the vibration isolation table 30 includes a surface plate 34 on which precision equipment 32 is mounted.
4 is supported by an air spring 36 attached to a frame 39 installed on the floor 38.

The air spring 36 may be of a bellows type, a diaphragm type or the like. Although only one air spring 36 is shown in the figure, a desired number of air springs 36 may be provided so as to correspond to the four corners of the surface plate 34, respectively. The air spring 36 has a spring constant such that vibration with a small amplitude, for example, vibration with a frequency of about 0.5 to 5 Hz can be effectively isolated.
Vibrations received from the floor 38 by the surface plate 34 on which 2 is mounted are converged in a short time.

As shown in FIG. 1, in the damper 10, the flange 14B of the piston portion 14 is attached to the lower surface of the surface plate 34 with bolts 41, and the cylinder 12 is attached to the frame 39 with bolts (not shown) or the like.

The electrode plate 20 of the cylinder 12 is set longer than the electrode plate 22 of the piston portion 14 by a predetermined dimension, and the center of the electrode plate 20 and the center of the electrode plate 22 are opposed to each other.

As shown in FIG. 3, the surface plate 34 includes a surface plate 3
A sensor 40 for detecting vibration or displacement of No. 4 is attached. The sensor 40 may be a displacement sensor or a vibration sensor such as an acceleration sensor or a speed sensor.
The sensor 40 is not installed on the surface plate 34,
It may be mounted on the 2 itself. Although only one sensor 40 is shown in the figure, the number of sensors is not limited to this.

Electrodes 20, 2 of the sensor 40 and damper 10
2 is connected to the drive unit 42 via a wiring (not shown). An on / off circuit 44 that inputs a detection signal from the sensor 40 and shapes a pulse, an amplifier circuit 46 that amplifies an output signal from the on / off circuit 44, and a pulse that is amplified by the amplifier circuit 46 is input to the drive unit 42. A driver 48 that sends a drive signal to the electrodes 20 and 22 of the damper 10 is provided. In this embodiment, the electrode 22 is the anode and the electrode 20 is the cathode.

Vibration or displacement of the surface plate 34 detected by the sensor 40 is appropriately processed, and a detection signal is output when the detected value is equal to or more than a certain value. When the sensor 40 is a speed sensor, the detected value can be differentiated to obtain the acceleration, and when the sensor 40 is an acceleration sensor, the detected value can be integrated to obtain the speed.

The damper 10 may be provided for each of the sensors 40, or may be provided for each of the two sensors, such as one for inputting detection signals sent from a plurality of sensors. good. Also, a plurality of dampers 10 may be controlled by one sensor.

Next, the operation of this embodiment will be described. Plate 3
When 4 vibrates due to the vibration generated from the installation surface such as the floor 38 or the mounted precision instrument 32 itself, the sensor 40 detects the vibration or displacement of the surface plate 34, and when the vibration or the displacement of a certain value or more is detected, the sensor A detection signal is sent from 40 to the drive unit 42.

The detection signal is shaped into a pulse by the on / off circuit 44, amplified by the amplifier circuit 46, and a drive signal is output from the driver 48. The driver 48 causes the damper 10 to output.
A desired voltage is applied to the electrodes 20 and 22 of the.

As a result, the viscosity of the electrorheological fluid 24 in the cylinder 12 to which the voltage is applied increases, and the damping constant of the damper 10 increases. For this reason, vibrations with large amplitude are damped in a short time and efficiently damped.

When the vibration or displacement detected by the sensor 40 becomes a certain value or less, the sending of the detection signal is stopped and the voltage is not applied to the electrodes 20 and 22 of the damper 10. The vibration with the reduced amplitude is damped by the damper 10 and the air spring 36 in the damping constant of the electrorheological fluid 24 to which no voltage is applied. Therefore, vibrations with small amplitude can be attenuated in a short time.

Further, in the damper 10 of this embodiment, since the cylinder 12 and the piston portion 14 are not connected to each other through anything other than the electrorheological fluid 24 in the operating state, the vibration of the installation surface such as the floor 38 is fixed. It is not transmitted to the board 34.

Not only the voltage is applied when the detection signal detected by the sensor 40 exceeds a certain value, but the amplitude of the vibration detected by the sensor 40 is set to a predetermined value in two steps or three steps. When divided into respective predetermined values, a detection signal is output to the drive unit 42, the voltage applied to the electrodes 20 and 22 is changed, and the electrorheological fluid 24 is changed to a desired viscosity according to the applied voltage. It is also possible to make the attenuation variable to efficiently perform the attenuation.

Here, when the damper 10 is stored or transported, as shown in FIG. 4, the flange 12C of the cylinder 12 and the flange 14B of the piston 14 are screwed together.
Use to adhere. As a result, the O-ring 18 is crushed by a predetermined amount and the inside is completely sealed, so that the electrorheological fluid 24 can be prevented from flowing out during transportation or the like, and foreign matter such as dust or dust enters the electrorheological fluid 24 during storage. Can be prevented.

The cylinder 12 may be formed of a transparent resin so that the electrorheological fluid 24 can be seen.

Further, in this embodiment, the screw hole 28 and the round hole 2
9 and the screw 50 correspond to the fixing means of the present invention. [Second Embodiment] A second embodiment of the present invention will be described with reference to FIGS. The same components as those in the first embodiment are denoted by the same reference numerals, and description thereof will be omitted.

As shown in FIG. 5, the damper 10 of the present embodiment.
The cylinder 12 has no flange.
A cylindrical slider portion 60 having a flange 60A is slidably mounted on the outer circumference of the cylinder 12. A round hole 52 is formed in the flange 60A of the slider portion 60 at a position corresponding to the screw hole 28 of the piston portion 14.

As shown in FIG. 6, a plurality of round holes 54 are formed in the cylindrical main body portion of the slider portion 60 along the outer peripheral direction at a position below a predetermined dimension from the upper surface.

In the cylinder 12, as shown in FIG.
When the flange 14B of the piston portion 14 is brought into close contact with the upper surface of the cylinder 12, a screw hole 56 is formed at a position corresponding to the round hole 54 of the slider portion 60, and as shown in FIG. A screw hole 58 is formed at a position corresponding to the round hole 54 of the slider portion 60 when the axial center portions are opposed to each other.

In the damper 10 of this embodiment, during storage or transportation, as shown in FIG. 6, the slider portion 60 is fixed to the flange 14B of the piston portion 14 with the screw 50, and the screw 59 is screwed into the screw hole 56. The slider part 60 is moved to the cylinder 12
Fixed to.

On the other hand, when assembling the damper 10 to the vibration isolation table 30, first, the screw 59 is once removed, the slider portion 60 is lifted, and the round hole 54 of the slider portion 60 and the cylinder 1 are removed.
The two screw holes 58 are aligned with each other, and a screw 59 is screwed into the screw hole 58 to obtain the state shown in FIG. 7. As a result, the axial center of the electrode 20 and the axial center of the electrode 22 face each other.

Next, the height of the surface plate 34 on which the precision instrument 32 is mounted is adjusted so that the damper 10 in the state shown in FIG. 7 can be inserted between the surface plate 34 and the frame 39.
0 is attached as shown in FIG. After fixing the damper 10, the slider portion 60 is lowered as shown in FIG.

As described above, by using the slider portion 60 as a mounting jig, the electrode 20 can be easily manufactured.
The damper 10 can be attached so that the axial center of the electrode and the axial center of the electrode 22 are correctly opposed, and the damper 10 can be operated in an appropriate state.

Regarding the damping function of the damper 10,
This is the same as the first embodiment. Further, in this embodiment, the screw hole 28, the round hole 52 and the screw 50 correspond to the fixing means of the present invention. Further, the slider portion 60 and the screw hole 58 correspond to the positioning means of the present invention. [Third Embodiment] A third embodiment of the present invention will be described with reference to FIGS. The same components as those in the above-described embodiment are designated by the same reference numerals and the description thereof will be omitted.

As shown in FIG. 8, in the piston portion 14 of this embodiment, the piston body 14A submerged in the electrorheological fluid 24 and the flange 14B used for mounting are smaller in diameter than the piston body 14A. Rod 14C
Are connected by

Further, the electrode plate 2 is attached to the piston body 14A.
An annular projecting portion 14D is integrally formed so as to be in contact with both axial end portions of 2. This overhanging portion 14D is the electrode 2
0 serves as a radial stroke stopper for preventing contact between the electrode 22 and the electrode 22 and preventing the electrode 22 from coming closer to a predetermined size or less.

Accordingly, in the damper 10 of this embodiment,
It is possible to prevent electric discharge between the electrodes when the cylinder 12 and the piston portion 14 are relatively displaced in the radial direction (for example, when the surface plate 34 moves largely in the horizontal direction).

Since discharge is likely to occur from the edge portion, it is effective to provide the protrusion of the insulator on the end portion of the electrode 22 as in this embodiment. The end of the electrode 22 may be covered with the protruding portion 14D.

Further, in the operation state as shown in FIG. 8, the liquid surface of the electrorheological fluid 24 is located below the upper surface of the cylinder 12 by a predetermined dimension, and between the cylinder 12 and the piston rod 14C. A large-capacity liquid reservoir 64 is provided. By providing the liquid reservoir portion 64, it is possible to prevent the electrorheological fluid 24 from spilling out of the cylinder 12 when the piston portion 14 is largely displaced vertically.

The other damping action of the damper 10 is the same as that of the first embodiment. During storage and transportation, as shown in FIG. 9, the slider portion 60 is fixed to the flange 14B of the piston portion 14 with the screw 50, and the screw 59 is screwed into the screw hole 56 to move the slider portion 60 into the cylinder 12.
Fixed to. [Fourth Embodiment] A fourth embodiment of the present invention will be described with reference to FIGS.
Follow the instructions below. The same components as those in the above-described embodiment are designated by the same reference numerals and the description thereof will be omitted.

As shown in FIG. 10, the damper 1 according to the present embodiment.
At 0, the annular projecting portion 14D provided on the piston portion 14 has a smooth round shape. Further, the piston portion 14 has a rounded shape with a large radius of curvature at the lower end,
An intermediate portion of the piston rod 14C (near the liquid surface of the electrorheological fluid 24 in the operating state) is depressed in an arc shape.

By forming the piston portion 14 in such a shape, it is possible to reduce resistance when the piston portion 14 moves in the electrorheological fluid 24 in the axial direction (vertical direction in the drawing).

The other damping action of the damper 10 is the same as that of the first embodiment. During storage or transportation, as shown in FIG. 11, the slider portion 60 is fixed to the flange 14B of the piston portion 14 with the screw 50, and the screw hole 56
A screw 59 is screwed on the slider portion 60 to attach the slider 1 to the cylinder 1.
Fix to 2. [Fifth Embodiment] A fifth embodiment of the present invention will be described with reference to FIGS. 12 and 13.
Follow the instructions below. The same components as those in the above-described embodiment are designated by the same reference numerals and the description thereof will be omitted.

The damper 10 of this embodiment is constructed so that not only the radial stroke but also the axial stroke can be restricted.

As shown in FIG. 12, a stopper 66 as a cylindrical dust intrusion preventing means is screwed to the lower surface of the flange 14B of the piston portion 14.

A stopper flange 66A is formed at the lower end of the stopper 66 and extends radially inward.

On the other hand, a male screw 68 is formed on the outer circumference of the cylinder 12, and an upper stopper 70 is screwed on the upper side and a lower stopper 72 is screwed on the lower side.

A flange 70A is formed at the upper end of the upper stopper 70 and extends radially outward. The outer diameter of the flange 70A is the same as the stopper flange 6 of the stopper 66.
It is set larger than the outer diameter of 6A, and the stopper 66
It is set to be smaller than the inner diameter of the cylindrical main body portion by a predetermined dimension.

The inner diameter of the stopper flange 66A is
The outer diameter of the cylindrical main body of the upper stopper 70 is set to be larger by a predetermined dimension.

In this embodiment, the inner surface of the stopper flange 66A abuts on the outer surface of the upper stopper 70, or the flange 70A of the upper stopper 70 abuts on the inner peripheral surface of the stopper 66, so that the cylinder 12 and the piston portion 14 are not in contact with each other. The amount of relative displacement in the radial direction between and is limited, thereby preventing discharge between the electrodes.

Further, when the axial center of the electrode 20 and the axial center of the electrode 22 face each other, between the flange 70A of the upper stopper 70 and the stopper flange 66A of the stopper 66, and between the stopper flange 66A and the lower stopper 72.
The positions of the upper stopper 70 and the lower stopper 72 are adjusted so that a space having a predetermined size is provided between the upper stopper 70 and the lower stopper 72. The vertical stroke of the piston portion 14 can be arbitrarily adjusted by changing the positions of the upper stopper 70 and the lower stopper 72.

As a result, the amount of relative displacement between the cylinder 12 and the piston portion 14 in the axial direction is limited, and the vertical movement of the liquid surface of the electrorheological fluid 24 is limited to a predetermined amount or less, so that the electrorheological fluid 24 is moved to the cylinder 12 by a predetermined amount. It is possible to prevent the electrode 22 from overflowing and to prevent the electrode 22 from being exposed above the liquid surface of the electrorheological fluid 24.

Further, in the present embodiment, since the opening portion of the cylinder 12 is covered with the stopper 66, it is difficult for foreign matter such as dust and the like to enter the electrorheological fluid 24 and the electrorheological fluid 24.
The characteristics of are stable.

The lower stopper 72 has a round hole 73,
A screw hole 75 is formed in the stopper flange 66A of the stopper 66.
13 is formed, the long screw 77 inserted into the round hole 73 is screwed into the screw hole 75 at the time of storage or transportation, as shown in FIG.
And the flange 14B of the piston portion 14 is brought into close contact with the upper surface of the cylinder 12.

The other damping function of the damper 10 is the same as that of the first embodiment. [Sixth Embodiment] A sixth embodiment of the present invention will be described with reference to FIG. The same components as those in the above-described embodiment are designated by the same reference numerals and the description thereof will be omitted.

As shown in FIG. 14, in this embodiment, a ring 74 having an inwardly extending flange 74A is attached to the upper portion of the cylinder 12 and
The lower end of the bellows 76 as a thin dust intrusion prevention film formed of an elastic body such as rubber is sandwiched between the lower end and the flange 74A.

On the other hand, a step portion 14E is formed on the piston portion 14, and a ring 78 is attached to this step portion 14E. An annular groove 80 is formed in the ring 78, and an O-ring 82 as a seal member is fitted in the groove 80. Also, the ring 78 and the step 14
The upper end of the bellows 76 is sandwiched between E and E.

The upper surface of the ring 74 and the slider portion 60
When the upper surface of the ring 74 is aligned with the upper surface of the ring 74, the screw hole 83 formed in the ring 74 and the round hole 85 formed in the vicinity of the flange 60A of the slider portion 60 face each other. And the upper surface of the slider portion 60 are aligned, and the slider portion 60 is fixed with screws 59.

Further, in the slider portion 60 of this embodiment, when the electrodes 20 and 22 are opposed to each other in their axial center portions,
A round hole 87 is formed at a position facing the screw hole 83 of the ring 74. Therefore, when the damper 10 is assembled to the vibration isolation table 30, a screw (not shown) inserted in the round hole 87 is screwed into the screw hole 83 of the ring 74, and the slider portion 60 is shown by an imaginary line (two-dot chain line) in the figure. In this way, the damper 10 can be attached with the electrodes 20 and 22 facing each other at appropriate positions.

In the damper 10 of this embodiment, the bellows 7
Since the inside is completely sealed by 6, the foreign matter and the like never enter the electrorheological fluid 24, and the characteristics are stable for a long period of time.

Since the bellows 76 is made of an elastic material such as rubber and has a thin wall, it is extremely flexible and does not transmit unnecessary vibrations to the surface plate 34 from the installation surface such as the floor 38.

The other damping action of the damper 10 is the same as that of the first embodiment. [Seventh Embodiment] A seventh embodiment of the present invention will be described with reference to FIGS.
Follow the instructions below. The same components as those in the above-described embodiment are designated by the same reference numerals, and the description thereof will be omitted.

As shown in FIG. 15 and FIG. 16, the piston portion 14 of this embodiment is integrally formed with a cylindrical portion 14F as a dust invasion preventing means extending downward on the lower surface of the flange 14B.

The inner diameter of the cylindrical portion 14F is set to be larger than the outer diameter of the cylinder 12 by a predetermined dimension, and serves as a radial stopper.

The flange 14 is provided on the inner surface of the cylindrical portion 14F.
A female screw 84 is formed on the base portion on the B side, and a male screw 86 is formed on the upper portion on the outer surface of the cylinder 12.
Therefore, when the damper 10 is transported, the inside can be sealed by screwing the female screw 84 and the male screw 86 as shown in FIG.

Further, in the damper 10 of this embodiment, the cylindrical portion 1
A bellows 88 is provided as a dust intrusion prevention film that covers the gap between the 4F and the cylinder 12. The bellows 88 has an upper end fitted in the groove 14G of the tubular portion 14F and a lower end fitted in the groove 12D of the cylinder 12. In addition,
When tightening or loosening the screw, if one end of the bellows 88 is removed, the bellows 88 will not be twisted.

In the damper 10 of this embodiment, the bellows 88 completely cut off the inside, so that no foreign matter or the like is mixed into the electrorheological fluid 24 and the characteristics are stable for a long period of time.

The other damping function of the damper 10 is the same as that of the first embodiment. In this embodiment, the female screw 8
4 and the male screw 86 correspond to the fixing means of the present invention. [Eighth Embodiment] An eighth embodiment of the present invention will be described with reference to FIGS. The same components as those in the above-described embodiment are designated by the same reference numerals, and the description thereof will be omitted.

As shown in FIG. 17, the piston portion 14 of this embodiment has a tapered bottom portion and a connecting portion between the piston body 14A and the piston rod 14C.

A flange plate 92 having a mounting screw hole 90 is fixed to the upper surface of the piston portion 14.

A cylindrical slider portion 94 is slidably provided on the outer periphery of the cylinder 12. The slider portion 94 is provided with four round holes 96, which are bored at equal intervals along the outer peripheral direction, in four rows in the axial direction.

In the damper 10 of this embodiment, the flange 14B is in close contact with the upper surface of the cylinder 12 at the time of storage or transportation and the screw 100 inserted into the round hole 96 in the uppermost row, as shown in FIG. Is screwed into the screw hole 98 formed in the flange 14B of the piston portion 14,
4 is fixed to the flange 14B, and the round hole 9 in the second row from the top
The screw 102 is inserted through the screw 6, and the screw 102 is inserted into the cylindrical portion 1
The slider portion 9 is screwed into the screw hole 104 of 2A.
4 is fixed to the cylinder 12.

On the other hand, when the damper 10 is attached to the vibration isolation table 30, as shown in FIG. 18, the screw 102 is inserted through the round holes 96 in the third row (or the fourth row) from the top, and the screw 1
02 is screwed into the screw hole 104 of the cylindrical portion 12A to fix the piston portion 14. In this embodiment, at this time, the electrode 20 and the electrode 22 face each other.

During operation, by removing the screws 100 and 102 and lowering the slider portion 94 as shown by the imaginary line (two-dot chain line) in the figure, the vibration of the installation surface such as the floor 38 is fixed. It is not transmitted to the board 34.

Regarding the damping function of the damper 10,
This is the same as the first embodiment. In this embodiment, the slider portion 9
4 and the screw hole 104 correspond to the positioning means of the present invention.

Further, in the above-described embodiment, the electrode plate 20 of the cylinder 12 is set to be longer than the electrode plate 22 of the piston portion 14 by a predetermined dimension. However, as shown in FIG. Electrode plate 20 and piston part 1
The four electrode plates 22 may be set to have the same length. In this case, the piston portion 14 is in the neutral position (position shown in FIG. 19).
The area of the part where the electrodes face each other decreases as it is displaced upward or downward from. That is, the piston portion 14
When is largely separated from the neutral position upward or downward, the portion where the electrorheological fluid 24 becomes highly viscous automatically decreases, and the piston portion 14 can be quickly returned to the neutral direction. Further, the damper 10 may have a structure in which the electrode plate 20 of the cylinder 12 is vertically divided into two parts, each of which is separated by a predetermined dimension. In this case, as shown in FIG. 20, as the piston portion 14 is displaced upward or downward, the area of the portion where the electrodes face each other increases. For this reason,
When the piston portion 14 tries to largely move upward or downward from the neutral position, the portion where the electrorheological fluid 24 becomes highly viscous increases, and the effect of suppressing the displacement of the piston portion 14 automatically increases. That is, it is possible to suppress the power when the amplitude is small and to apply the power according to the amplitude when the amplitude is large. When the lengths of the electrode plate 20 and the electrode plate 22 are determined so that the areas of the electrodes facing each other do not change depending on the amplitude, the same action should be obtained depending on the control method. Although it is possible, the control by the drive unit 42 becomes complicated.

[0098]

As described above, since the damper according to claim 1 has the above-mentioned structure, the following (1) to (3) are provided.
The effect of is obtained. (1) By using the electrorheological fluid, vibration can be damped in a short time with good responsiveness. Further, the damper can be downsized, and a large-scale device is not required. (2) Since the cylinder opening can be closed by the closing means when not in operation, the electrorheological fluid can be prevented from flowing out during transportation and the portability is improved. Further, it is possible to prevent foreign matter from entering the electrorheological fluid during storage or the like. (3) When the damper is in operation, since the closing means does not contact the cylinder, the closing means does not transmit vibration from the cylinder to the piston or from the piston to the cylinder, and vibration can be reliably suppressed. Since the damper has the above-mentioned configuration, it has an excellent effect that the inside of the cylinder can be completely sealed and the outflow of the electrorheological fluid can be reliably prevented.

Since the damper described in claim 3 has the above-mentioned structure, it has an excellent effect that foreign matter such as dust and dirt can be prevented from entering the electrorheological fluid in a use state. Further, since vibration is not transmitted from the cylinder to the piston or from the piston to the cylinder through the dust entry preventing means, there is an excellent effect that vibration can be reliably suppressed.

Since the damper described in claim 4 has the above-mentioned structure, it has an excellent effect that the inside of the cylinder is completely sealed and the entry of dust or other foreign matter into the electrorheological fluid can be reliably prevented.

Since the damper described in claim 5 has the above-mentioned structure, it has an excellent effect that the damper can be easily attached in a correct state and the damper can be operated properly.

[Brief description of drawings]

FIG. 1 is a sectional view of a damper according to a first embodiment attached to a vibration isolation table.

FIG. 2 is a plan view of a flange of a piston portion.

FIG. 3 is a configuration diagram of a vibration isolation table.

FIG. 4 is a cross-sectional view of the sealed damper according to the first embodiment.

FIG. 5 is a sectional view of a damper according to a second embodiment attached to a vibration isolation table.

FIG. 6 is a cross-sectional view of the damper according to the second embodiment which is hermetically sealed.

FIG. 7: Second height adjustment before mounting on the vibration isolation table
It is sectional drawing of the damper which concerns on an Example.

FIG. 8 is a sectional view of a damper according to a third embodiment attached to a vibration isolation table.

FIG. 9 is a cross-sectional view of a damper according to a third embodiment which is hermetically sealed.

FIG. 10 is a sectional view of a damper according to a fourth embodiment attached to a vibration isolation table.

FIG. 11 is a cross-sectional view of a sealed damper according to the fourth exemplary embodiment.

FIG. 12 is a sectional view of a damper according to a fifth embodiment attached to a vibration isolation table.

FIG. 13 is a cross-sectional view of the damper according to the fifth exemplary embodiment that is hermetically sealed.

FIG. 14 is a sectional view of a damper according to a sixth embodiment attached to a vibration isolation table.

FIG. 15 is a sectional view of a damper according to a seventh embodiment attached to a vibration isolation table.

FIG. 16 is a sectional view of a damper according to a seventh embodiment which is hermetically sealed.

FIG. 17 is a sectional view of a damper according to an eighth embodiment attached to a vibration isolation table.

FIG. 18 is a sectional view of a damper according to an eighth embodiment attached to a vibration isolation table.

FIG. 19 is a sectional view of a damper according to another embodiment.

FIG. 20 is a sectional view of a damper according to another embodiment.

[Explanation of symbols]

 10 Damper 12 Cylinder 14 Piston Part 14B Flange (Closing Means) 14F Cylinder Part (Dust Entry Prevention Means) 18 O-ring (Seal Member) 20 Electrode (First Electrode) 22 Electrode (Second Electrode) 24 Electrorheological Fluid 28 Screw hole (fixing means) 29 Round hole (fixing means) 50 Screw (fixing means) 52 Round hole 52 (fixing means) 58 Screw hole (positioning means) 60 Slider part (positioning means) 66 Stopper (dust entry preventing means) ) 76 bellows (dust entry prevention film) 82 O-ring (sealing member) 84 female screw (fixing means) 86 male screw (fixing means) 88 bellows (dust entry prevention film) 94 slider part (positioning means) 104 screw hole (positioning) means)

Front page continuation (72) Inventor Kimio Uchida 2-1-1 Oda Sakae, Kawasaki-ku, Kawasaki-shi, Kanagawa Showa Electric Wire & Cable Co., Ltd. (72) Inventor Hiroyuki Yamaya 3-1-1 Ogawa-higashi, Kodaira-shi, Tokyo Inside the Bridgestone Tokyo Plant (72) Inventor Satoshi Kawasan 3-1-1 Ogawahigashicho, Kodaira-shi, Tokyo Inside the Bridgestone Tokyo Plant (72) Yuichi Ishino 3-1-1 Ogawahigashi-cho, Kodaira-shi, Tokyo Inside the Bridgestone Tokyo factory (72) Inventor Shigeki Endo 3-1-1 Ogawahigashi-cho, Kodaira-shi, Tokyo Inside the Bridgestone Tokyo factory

Claims (5)

[Claims] 1. A cylinder having an open upper portion for containing an electrorheological fluid whose viscosity changes when a voltage is applied, a piston disposed in the viscous fluid, and a voltage applied to the electrorheological fluid provided in the cylinder. A first electrode for applying a voltage, a second electrode provided on the piston to face the first electrode and apply a voltage to the electrorheological fluid, and a second electrode connected to the piston and not operating A damper that closes the opening to block the outflow of the electrorheological fluid. 2. A sealing member made of an elastic material is provided on at least one of the closing means and the cylinder, and when the opening of the cylinder is closed, the cylinder is brought into close contact with the other side to completely seal the cylinder. The damper described in 1. 3. The damper according to claim 1 or 2, further comprising a dust intrusion prevention unit that covers the opening in a non-contact state. 4. The damper according to claim 1, further comprising a low-rigidity dust intrusion prevention film that seals the inside of the cylinder. 5. A positioning means for indicating a position where the first electrode and the second electrode face each other is provided, and the positioning means is provided. damper.