JPH05231471A - Vibration isolator - Google Patents

Abstract

PURPOSE:To provide a vibration isolator capable of completely isolating horizontal vibration of small-medium amplitude by suspending a vibration isolating base floor plate in the state of being levitated from an installation floor and allowing the vibration isolating base floor plate to be returned into the original balanced position against the vibration of large amplitude, disturbance and the like. CONSTITUTION:A vibration isolator is formed of a magnetic body 4 fixed to a vibration isolating base floor plate 1, and electromagnets 5 fixed to the installation floor 3 side so as to support the magnetic body 4 in the non-contact state by magnetic force. The magnetic body 4 fixed to the vibration isolating base floor plate 1 is provided with coils 7 at the parts opposed to the yokes 9 of the electromagnets 5, and a current is applied to the coils 7 by the signals of displacement sensor 8 or the like to move the vibration isolating base floor plate 1.

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, it suspends an anti-vibration pedestal floor plate equipped with a mechanical device that dislikes vibration.
The present invention relates to a vibration isolation device that removes vibrations from a floor on which a vibration isolation table is installed.

[0002]

2. Description of the Related Art Conventionally, mechanical devices such as an electron microscope and a semiconductor manufacturing device, 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 so that the vibration of the installation floor is not transmitted to the mechanical device mounted on the vibration isolation base floor plate by the air spring. Was becoming. However, the air-spring type vibration isolation device is mechanical and cannot completely remove vibrations. In particular, 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 prior art, the present invention completely eliminates vibrations of small and medium amplitudes by suspending and suspending a vibration isolation base floor plate from the installation floor. (EN) Provided is a vibration isolation device capable of moving a floor plate of a vibration isolation table so as not to give a large impact to a mounted mechanical device even with respect to vibrations and large disturbances.

[0004]

The vibration isolator according to the present invention comprises a magnetic body fixed to a vibration isolation base floor plate and an electromagnet fixed to the installation floor side for supporting the magnetic body in a non-contact manner by magnetic force. The magnetic body fixed to the vibration isolation base floor plate is provided with a coil at a portion facing the yoke of the electromagnet, and the vibration isolation is performed by applying a current to the coil by a signal from a displacement sensor or the like. Move the base plate.

[0005]

When the exciting current flows, the 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 table floor plate fixed to the magnetic body is in a state of being suspended and suspended in a non-contact manner with respect to the installation floor side. Therefore, the vibration on the installation floor side in the horizontal direction is not transmitted because the vibration isolation base floor plate is in non-contact and is suspended, and the mechanical device mounted on the vibration isolation base floor plate is
The vibration on the installation floor side is not transmitted, that is, is isolated. Furthermore,
The magnetic body fixed to the floor plate of the vibration isolation table is provided with a coil at a portion facing the yoke of the electromagnet. Since this coil is located in a portion facing the yoke of the electromagnet, it is in a position to cross the magnetic flux formed between the yoke of the electromagnet and the magnetic body. Therefore, when an electric current is applied to the coil, the coil receives a force from the magnetic field and moves the vibration isolation base plate. Therefore, by detecting a large-amplitude signal with a displacement sensor or the like, an electric current is passed through a coil provided on the magnetic body, so that the vibration isolation base plate can be moved to the original equilibrium position.

[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 composed of an electromagnet. The actuator 2 is
It is installed on the installation floor 3 and supports the vibration isolation floor plate 1 at the four corners as shown in the figure. On the vibration isolator 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 10. The magnetic disk 4 is a magnetic material having a high magnetic permeability. The electromagnet 5 is fixed to the installation floor 3. 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 electromagnet 5. A coil 7 is provided at a portion of the magnetic disk 4 facing the yoke 9 of the electromagnet 5. Displacement sensor 8
Is a target provided on the magnetic disk 4,
The relative displacement between the magnetic disk 4, that is, the vibration isolation floor plate 1 and the installation floor is detected.

FIG. 2 is an explanatory view of a coil provided on the magnetic disk of the vibration isolator according to one embodiment of the present invention. The magnetic disk 4 is provided with four U-shaped coils 7 as shown in the drawing. The position of the U-shaped coil 7 faces the yoke 9 of the annular electromagnet 5. That is, the outward path of the U-shaped coil faces the outside of the yoke 9, and the return path of the coil 7 faces the inside of the yoke 9.

Next, the operation of this vibration isolator will be described. When an exciting current flows in the coil of the electromagnet 5, the electromagnet 5
A magnetic circuit is formed between the yoke 9 and the magnetic disk 4, and a magnetic flux 11 is generated in the direction shown. This magnetic flux 1
Due to the attraction force of 1, the magnetic disk 4 floats in a non-contact manner. At the position where the gravity including the mechanical device mounted on the vibration isolation base floor plate 1 and the magnetic attraction force of 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. The electromagnet 5 is fixed to the installation floor 3, and due to the magnetic attraction of the electromagnet 5,
An anti-vibration base plate 1 on which a mechanical device is mounted is suspended. Therefore, the electromagnet 5 supports the vibration isolation base plate 1 only by the force in the vertical direction. In the horizontal direction, the magnetic disk 4 is larger than the yoke 9, so that the horizontal magnetic attraction force by the electromagnet 5 is not generated.

Now, assuming that the installation floor 3 vibrates in the horizontal direction, the electromagnet 5 vibrates together with the installation floor 3 in the horizontal direction. However, since the electromagnet 5 has no horizontal force on the magnetic disk 4, the magnetic disk 4 receives no force. Therefore, even if the installation floor 3 vibrates in the horizontal direction, the magnetic disk 4, that is, the vibration isolation floor plate 1 having the mechanical device mounted thereon remains stationary in the horizontal direction. That is,
The vibration is not transmitted to the vibration isolation base floor plate 1 and is isolated.

However, when a large amplitude vibration is applied,
The installation floor 3 is largely displaced with respect to the magnetic disk 4,
In an extreme case, the electromagnet 5 collides with the support member 10 that connects and fixes the vibration isolation base plate 1 to the magnetic disk 4. When the electromagnet 5 collides with the support member 10, a large impact is applied to the mechanical device mounted on the vibration isolation floor plate 1. Further, when a horizontal force is applied to the vibration isolation base floor plate 1 for some reason, since there is no horizontal restraining force, the vibration isolation base floor plate 1 similarly moves beyond the control range ( Step out). The magnetic disk 4 is provided with a coil 7 in order to prevent step-out due to such large amplitude or disturbance.

Since the coil 7 is provided in the portion of the magnetic disk 4 facing the yoke 9 of the electromagnet 5, the coil 7 is orthogonal to the magnetic flux generated by the yoke 9 of the electromagnet 5. When a current is applied to the U-shaped coil 7, a force 12 as shown in FIG. 1 is generated in the coil 7 by Fleming's left-hand rule, as shown in FIG. Here, the forward current and the backward current of the U-shaped coil 7 flow in opposite directions, and the magnetic flux formed between the yoke 9 and the magnetic disk 4 is also reversed inside and outside due to bankruption of the coil of the electromagnet 5. Formed in the direction. Therefore, the force 12 is the U-shaped coil 7
The same direction can be obtained on the outward and return routes. This force 12 accelerates the magnetic disk 4 in the horizontal direction. Therefore, since the magnetic disk 4 can be moved in the horizontal direction, it is possible to prevent the problem that the magnetic disk 4 largely moves and loses the step and collides with the yoke 9 of the electromagnet 5. ..

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 electromagnet 5 as an exciting current. When an exciting current flows through the 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. Then, the magnetic disk 4 detected by the displacement sensor 8
When the position No. has not reached the flying position designated by the flying position command signal 15, the difference is amplified and a larger exciting current is applied by the phase compensation circuit 18 and the drive circuit 19, so that the magnetic disk is stronger. It levitates to a higher position due to magnetic attraction. With such a feedback control system, the position of the magnetic disk 4 is
Ascend 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 one embodiment of the present invention. First, a desired equilibrium position is set at the horizontal setting position 21. Then, the displacement sensor 8 detects the displacement of the magnetic disk 4 in the horizontal direction. The horizontal setting position 21 and the output of the displacement sensor 8 are compared, and the difference is input to the phase compensation circuit 22 and the comparator 25. In the comparator 25, an allowable displacement, that is, an allowable displacement for preventing step-out is inputted in advance, and the difference between the horizontal setting position 21 and the output of the displacement sensor 8 is compared.

When the horizontal displacement of the magnetic disk 4 becomes large due to large-amplitude vibration or disturbance, and exceeds the allowable displacement, the multiplexer 24 is brought into conduction by the output of the comparator 25. In such a case, the phase is adjusted by the phase compensation circuit 22 and the gain is adjusted by the amplifier circuit 23 in proportion to the horizontal displacement, and the current is amplified by the push-pull drive circuit 26 through the multiplexer 24 and applied to the coil 7. To be done. When a current flows through the coil 7, the force 12 shown in FIG. 1 is generated by Fleming's left-hand rule. As a result, the magnetic disk 4 is
It is returned to the original equilibrium position, and the magnetic disk 4 is prevented from losing synchronization.

When the amplitude is small and does not exceed the allowable range set in the comparator 25, the comparator 25 does not operate and the multiplexer 24 is also turned off. In this case, since no current flows through the coil 7, no horizontal force is applied and the vibration isolation base plate 1 is completely isolated in the horizontal direction.

Further, an acceleration sensor is attached to the vibration isolation base floor plate 1 to detect acceleration in the horizontal and vertical directions, and based on this signal, the coils on the magnetic body in the horizontal and vertical directions, and
It is possible to control the current of the levitation electromagnet. For example, in the horizontal direction, the acceleration sensor 13 attached to the vibration isolation floor plate 1 integrates the acceleration signal to generate a velocity signal as shown in the block diagram of FIG. 6, and the output signal is output in the horizontal direction of FIG. It is applied to the terminal indicated by the symbol x in the control block diagram. In the control system shown in FIG. 4, by providing the coil 7 with an exciting current that cancels the horizontal speed of the vibration isolation base plate 1, damping of horizontal cooperation of the vibration isolation base plate 1 caused by disturbance is performed. Can be given. By such control, it becomes possible to perform vibration isolation in the horizontal and vertical absolute coordinate systems.

[0018]

As described in detail above, the vibration isolator of 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. Therefore, even if the installation floor side vibrates, a horizontal force is not applied to the magnetic body, so that the magnetic body is completely vibration-isolated, and the vibration is not transmitted to the mechanical device mounted on the vibration-isolation base plate. Further, the magnetic body is provided with a coil at a portion facing the yoke of the electromagnet, and the vibration isolation base plate can be moved by applying a current to the coil by a signal from a displacement sensor or the like. Therefore, due to large amplitude vibration, disturbance, etc.,
When a certain allowable range is exceeded, the vibration isolation base plate can be moved and returned to the original equilibrium position by applying a current to the coil.

[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 an explanatory diagram of a coil included in a magnetic disk of a vibration isolation device according to an 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 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.

FIG. 6 is a block diagram for generating a velocity signal from an acceleration signal.

[Explanation of symbols]

 1 Vibration Isolation Floor Plate 2 Actuator 3 Installation Floor 4 Magnetic Disk 5 Electromagnet 7 Coil 8 Displacement Sensor 9 Yoke 10 Supporting Member 11 Magnetic Flux 12 Force 13 Accelerometer

Claims (1)

[Claims] 1. A magnetic body fixed to an anti-vibration base plate, an electromagnet fixed to the installation floor side for supporting the magnetic body in a non-contact manner by a magnetic force, and a portion of the magnetic body facing the yoke of the electromagnet. 2. A vibration isolation device comprising: a coil; and means for moving the vibration isolation base floor plate by applying a current to the coil.