JPH0642583A - Damping device - Google Patents

Abstract

PURPOSE:To provide a damping device which is capable of damping the vibration of small amplitude by executing the levitational suspension of a floor plate of a damping table above a setting floor. CONSTITUTION:A damping device consists of a magnetic body 4 to be fixed to a floor plate 1 of a damping table, and an electromagnet 5 for levitation which is fixed to a setting floor 3 side to support the magnetic body 4 by the magnetic attraction in a non-contact manner, and thin magnetic pole parts 14 are provided on the respective corner parts of the magnetic body 4, and a controlling electromagnet 7 having a yoke 10 close to the magnetic pole part 14 is also provided.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an anti-vibration device, and in particular, an anti-vibration device for removing vibrations from a floor on which an anti-vibration table is installed by suspending an anti-vibration table floor plate equipped with a mechanical device that dislikes vibrations. Regarding

[0002]

2. Description of the Related Art Conventionally, mechanical devices such as electron microscopes and semiconductor manufacturing devices, which are extremely reluctant to vibrate, have been used by being mounted on a vibration isolation device. An air spring system is an example of a conventional vibration isolation device. Mechanical devices such as electron microscopes and semiconductor manufacturing equipment are mounted on a vibration isolation base floor plate equipped with an air spring, and the vibration of the installation floor is absorbed by the air spring and is not transmitted to the mechanical device mounted on the vibration isolation base floor plate. It was like this. However, the air-spring type vibration isolation device is mechanical and cannot completely remove vibrations, and it is difficult to completely remove minute vibrations. Further, it is impossible to absorb the large vibration exceeding the limit of the air spring, which may give a shock to the electron microscope or the like mounted on the floor plate of the vibration isolation table.

[0003]

SUMMARY OF THE INVENTION In view of the problems of the related art, the present invention further detects the acceleration of the vibration isolation base floor plate by suspending the vibration isolation base floor plate from the installation floor, and detects the acceleration. By providing a control means for canceling the vibration of the above, it is possible to provide a vibration isolator capable of completely eliminating even the vibration of a small amplitude of the installation floor.

[0004]

A vibration isolator according to the present invention comprises a magnetic body fixed to a floor plate of a vibration isolation base, and a levitation electromagnet fixed to a floor for non-contact support of the magnetic body by magnetic force. The magnetic body fixed to the floor plate of the vibration isolation table is provided with thin magnetic pole portions on four sides through a non-magnetic body, and is equipped with a control electromagnet for exerting a magnetic attraction force on the magnetic pole portion. By detecting the acceleration of the shaking table floor plate, the excitation of the control electromagnet is controlled so as to cancel the vibration applied to the vibration damping table floor plate.

[0005]

When the exciting current flows, the levitation electromagnet fixed to the installation floor side attracts and floats the magnetic material fixed to the vibration isolation base floor plate by the magnetic attraction force. Therefore, the vibration isolation base floor plate fixed to the magnetic body is in a state of being suspended and suspended without contact with the installation floor side. Further, the magnetic body fixed to the floor plate of the anti-vibration table has thin magnetic pole parts on all sides through a non-magnetic body,
A control electromagnet having a yoke is provided near the magnetic pole portion. Therefore, by detecting the acceleration of the vibration isolation base floor plate, a magnetic attraction force that cancels vibration is applied to the thin plate of magnetic material from the yoke of the control electromagnet, whereby the vibration isolation base floor plate is It is also isolated from vibrations with a small amplitude on the installation floor.

[0006]

FIG. 5A is a plan view and FIG. 5B is a side view of a vibration isolator according to an embodiment of the present invention. The anti-vibration base plate 1 is suspended and suspended by an actuator 2 made of an electromagnet. The actuator 2 is
It is installed on the installation floor 3 and supports the vibration isolation table floor plate 1 at four points as shown in the figure. On the vibration isolation base floor plate 1, a mechanical device such as an electron microscope and a semiconductor manufacturing device that is extremely reluctant to vibrate is mounted.

FIG. 1 is an explanatory view of an actuator portion of a vibration isolator according to an embodiment of the present invention. The vibration isolation floor plate 1 is connected and fixed to the magnetic disk 4 via the support member 12. The magnetic disk 4 is a magnetic material having a high magnetic permeability. The levitation electromagnet 5 is fixed to the installation floor 3. The electromagnet 5 is an annular coil wound around a yoke 9, and the yoke 9 faces the magnetic disk 4. That is, the yoke 9 and the magnetic disk 4 form a magnetic circuit of the levitation electromagnet through the gap therebetween. The displacement sensor 8 detects the relative displacement between the magnetic disk 4, that is, the vibration isolation floor plate 1 and the installation floor, by the target provided on the magnetic disk 4.

Thin magnetic pole portions 14 are provided at four ends of the magnetic disk 4 with a non-magnetic material 11 interposed therebetween. A control electromagnet 7 having a yoke 10 is arranged at both ends of the thin magnetic pole portion 14 so as to be slightly shifted and close to each other. York 10
Has a tapered tip and a thin magnetic pole portion 14
And a magnetic circuit is formed through the void. FIG. 2 is a plan view of an actuator portion of the vibration isolation device according to the exemplary embodiment of the present invention. When the control electromagnets 7 arranged on the four sides of the magnetic disk 4 are excited by the coil 13, the control electromagnets 7 pass from the yoke 10 having a tapered tip end to a thin magnetic pole portion 14 which is slightly deviated and approached through an air gap. Then, a magnetic circuit returning to the yoke 10 via the air gap is formed again, and a magnetic flux is formed. Since the tip of the yoke 10 is tapered and the magnetic pole portion 14 is thin, the magnetic flux concentrates in a narrow range and a strong magnetic shearing force is generated even with a minute amplitude. The thin magnetic pole portion 14 is located inside the taper-shaped yoke 10 of the control electromagnets 7 on the four sides, which is slightly deviated and close to the tapered yoke 10. Therefore, when the control electromagnet 7 is excited, the thin magnetic pole portion 14
Receives a horizontal force due to the magnetic shearing force of the yoke 10. That is, when the control electromagnet 7 on the right side of the drawing is excited, the magnetic disk 4 receives a horizontal force in the right direction (X direction), and this force is proportional to the magnitude of the exciting current.
In this way, the electromagnets for control, which are provided close to the thin magnetic poles at the four ends of the magnetic disk 4, apply a force to the magnetic disk 4 in any direction on the XY plane. You can

Next, the operation of the vibration isolator will be described. In FIG. 1, when an exciting current flows through the coil of the levitation electromagnet 5, a magnetic circuit is formed between the yoke 9 of the levitation electromagnet 5 and the magnetic disk 4 via a gap, and a magnetic flux is generated. Due to the magnetic attraction of this magnetic flux, the magnetic disk 4 floats in a non-contact manner. At the position where the gravity including the mechanical devices mounted on the vibration isolation base floor plate 1 and the magnetic attraction force by the electromagnet 5 are balanced, the magnetic disk 4 or the vibration isolation base floor plate 1 is in contact with the installation floor 3 in a non-contact manner. Suspended and held. That is,
Since the levitation electromagnet 5 is fixed to the installation floor 3, the vibration isolation floor plate 1 on which the mechanical device is mounted is suspended from the installation floor 3 by levitation. Therefore, the levitation electromagnet 5 supports the vibration isolation base plate 1 mainly by the force only in the vertical direction. In the horizontal direction, the magnetic disk 4 is supported by the magnetic shearing force generated on the outer circumference of the yoke 9 of the levitation electromagnet 5 and the magnetic disk 4, and the magnetic shearing force generated on the control electromagnet 7 and the thin magnetic pole portion 14. There is.

The anti-vibration base plate 1 is provided with an acceleration sensor 6 to perform horizontal control according to the horizontal acceleration.
The acceleration sensor 6 detects the XY-direction acceleration of the vibration isolation floor plate 1 and excites the control electromagnet 7 with a magnetic attraction force in the XY direction that cancels the vibration on the floor plate. The thin magnetic pole portion 14 is provided. Thin magnetic pole part 14
Is connected to the magnetic disk 4 via the non-magnetic material 11, and the tip of the yoke 10 of the control electromagnet 7 is tapered, so that a strong magnetic attraction force against vibration with a small amplitude is obtained. Can be operated.

FIG. 3 is a block diagram of vertical control of the vibration isolator according to an embodiment of the present invention. Flying position command signal 15
The desired vertical flying position of the magnetic disk 4 is designated by. Ascending position designation signal 1 by the comparator 17
5 is compared with the signal obtained by amplifying the signal of the displacement sensor 8 by the displacement sensor amplifier 16. And displacement sensor amplifier 16
If the output of 1 does not reach the flying position command signal 15, the phase is adjusted by the phase compensation circuit 18 by the difference,
The power is amplified by the drive circuit 19 and applied to the coil of the levitation electromagnet 5 as an exciting current. When an exciting current flows through the levitation electromagnet 5, a magnetic attraction force is generated with respect to the magnetic disk 4, which is a magnetic material, and the magnetic disk 4 floats. With such a feedback control system,
The position of the magnetic disk 4 flies to the position designated by the flying position command signal 15.

FIG. 4 is a block diagram of horizontal control of the vibration isolator according to an embodiment of the present invention. An acceleration sensor 6 installed on the vibration isolation table floor plate 1 detects the horizontal acceleration applied to the vibration isolation table. Then, the detected acceleration is input to the amplifier circuit 21 as it is, converted to speed information by being integrated by the integrating circuit 20 and input to the amplifier circuit 21, or the displacement information is integrated twice. And input to the amplifier circuit 21. Then, after being amplified by the amplification circuit 21 having a constant gain, the rectification detection circuit 2
In 2, the + side and-side are distributed, the power is amplified by the drive circuit 23, and the amplified power is applied to the coils 13 of the control electromagnets 7R and 7L on the right side.

By exciting the control electromagnet 7 with the acceleration information (), the total weight of the apparent vibration isolation base plate 1 increases and the natural vibration value decreases. By passing the acceleration signal through the integration circuit and exciting the control electromagnet 7 with the speed information (), the peak of the natural vibration can be suppressed. Further, by exciting the control electromagnet 7 with the displacement information (), the spring rigidity from the virtual support point is increased, and the level of the natural vibration system can be lowered.

Therefore, as a whole, by exciting the control electromagnet 7 based on the horizontal acceleration of the acceleration sensor 6 mounted on the anti-vibration base plate 1, the horizontal direction applied to the anti-vibration base plate 1 can be increased. It is possible to perform vibration removal control that cancels the vibration and eliminates the peak of the natural vibration value.

Further, it is conceivable to attach a vertical acceleration sensor to the vibration isolation base floor plate 1, detect the vertical acceleration, and control the exciting current of the levitation electromagnet in the vertical direction based on this signal. . By such control,
It is possible to perform vibration isolation in the horizontal and vertical absolute coordinate systems.

[0016]

As described in detail above, the vibration isolator according to the present invention levitates the magnetic body fixed to the vibration isolation base floor plate in a non-contact manner by the magnetic force of the electromagnet fixed to the installation floor side. Is. Thin magnetic pole portions are provided at four ends of the magnetic body via a non-magnetic body, and a control electromagnet having a yoke close to the magnetic pole portion is provided. Therefore, by detecting the horizontal acceleration of the anti-vibration base plate and exciting the control electromagnet so as to cancel the force applied to the anti-vibration base plate, the vibration of all floors from small amplitude to large amplitude can be detected. Can be removed (vibrated). In particular, the end of the magnetic body is provided with a thin magnetic pole through a non-magnetic body, and the yoke of the control electromagnet has a tapered tip, which enables vibration isolation with a small amplitude.

[Brief description of drawings]

FIG. 1 is an explanatory diagram of an actuator portion of a vibration isolation device according to an embodiment of the present invention.

FIG. 2 is a plan view of an actuator portion of the vibration isolation device according to the exemplary embodiment of the present invention.

FIG. 3 is a block diagram of vertical control of a vibration isolation device according to an embodiment of the present invention.

FIG. 4 is a block diagram of horizontal control of a vibration isolation device according to an exemplary embodiment of the present invention.

FIG. 5 (a) is a plan view of a vibration isolation device according to an embodiment of the present invention,
(B) A side view.

[Explanation of symbols]

 1 Vibration Isolator Floor Plate 2 Actuator 3 Installation Floor 4 Magnetic Disk 5 Levitation Electromagnet 6 Acceleration Sensor 7 Control Electromagnet 8 Displacement Sensor 9 Yoke 10 Yoke 11 Non-Magnetic Material 12 Supporting Member 13 Coil 14 Thin Magnetic Pole

Claims (3)

[Claims] 1. A magnetic body fixed to a floor plate of an anti-vibration table, a levitation electromagnet fixed to the installation floor side for supporting the magnetic body in a non-contact floating manner by a magnetic force, and four end portions of the magnetic body. And a control electromagnet having a yoke that is slightly deviated from and close to the magnetic pole portion. 2. The anti-vibration table floor plate is provided with an acceleration sensor, and the control electromagnet applies a magnetic attraction force to the thin magnetic pole portion so as to cancel the detected vibration of the anti-vibration table. The vibration isolator according to claim 1, which is caused to act. 3. The vibration isolator according to claim 1, wherein the yoke of the control electromagnet has a tapered end.