JPH09100869A - Vibration resistant device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To facilitate horizontal positioning by providing a vertically supporting air spring on a variation resistant table, a magnetic substance on the vibration resistant table, and an electromagnet on an installation floor side, controlling pressure of the air spring by a signal of a displacement sensor, and controlling magnetic attracting force by a signal of an acceleration sensor. SOLUTION: A vibration resistant table 10 is vertically supported by an air spring 11, a member 18 of a common base 12 on the installation floor side and a member 10 on the vibration resistant table 10 side are connected to each other by a spring member 19, and the vibration resistant table 10 is positioned in the position balancing with the center in the clearance of an electromagnet in the horizontal direction by spring force. A displacement sensor detects the pole of the electromagnet fixed on the installation floor side and the clearance of a magnetic substance fixed on the vibration resistance table side, and performs vertical positioning by the signal. Vibration detected by an acceleration sensor 13 is removed by controlling magnetic attracting force of an electromagnetic actuator 15. Accordingly, since horizontal positioning can be performed by a weak spring without using any actuator, and the vibration resistance performance can be prevented from being deteriorated caused by the contact of the vibration resistant table with the actuator on the installation floor side.

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 supports an anti-vibration table equipped with a mechanical device which is not sensitive to slight vibrations with an air spring, and the vibration detected on the anti-vibration table of an electromagnet. The present invention relates to a vibration isolation device that removes by controlling magnetic attraction force.

[0002]

2. Description of the Related Art Conventionally, mechanical devices such as an electron microscope and a semiconductor manufacturing device that are not sensitive to microvibration have been mounted on a vibration isolation device and installed in a factory or the like. As a conventional vibration isolator, an active vibration isolator capable of realizing high-performance vibration isolator has been developed in place of a passive air isolator or a passive one using rubber. Among these, an anti-vibration device has been devised which supports the anti-vibration table with an air spring and removes the vibration by controlling the magnetic attraction force of the electromagnet (for example, JP-A-2-2661).
No. 34).

The anti-vibration device described in the above publication supports an anti-vibration table equipped with a device that dislikes minute vibrations vertically with an air spring so that the vibration of the installation floor itself is not directly transmitted to the anti-vibration table. I have to. Along with that, an acceleration sensor is provided on the vibration isolation table, and the vibration on the vibration isolation table detected by the sensor is isolated by controlling the magnetic attraction force exerted on the magnetic body fixed by the electromagnet on the vibration isolation table. doing.

[0004]

In the vibration isolator using the electromagnet as an actuator, the magnetic material on the vibration isolation table side is always in contact with the X and Y ( Must be positioned horizontally). However, the vibration isolator described above does not perform any particular positioning in the horizontal direction, but is merely passively supported by the rigidity of the air spring in the horizontal direction. Air springs have variations in characteristics, and due to the characteristics of rubber or the assembly accuracy, there is a steady horizontal displacement, and the magnetic poles of electromagnets fixed to the installation floor and the vibration isolation table supported by the air springs. There was a risk of contact with the magnetic substance fixed to the side and damaging the device.

This positioning can be performed by an electromagnet, but if the weight of the mounted object on the vibration isolation table is large, the rigidity of the air spring that supports it becomes high, and the capacity of the electromagnet for positioning becomes large. In connection with this, the capacity and size of the current amplifier for exciting the electromagnet and the power supply also increase. Also, a horizontal positioning controller is required.

Although it is not impossible to control the position in the horizontal direction by attaching an air spring so that the actuator can be positioned in the horizontal direction, the mechanism becomes complicated, and a control device is required. Space is also required. In any case, it is necessary to position the actuator in the horizontal direction, and the size increases,
Also, the cost will increase.

The present invention has been made in view of the above-mentioned circumstances, and in a vibration isolation device provided with an air spring, horizontal positioning can be easily performed without using a complicated actuator, and the device is supported by the air spring. An object of the present invention is to provide a vibration isolation device capable of preventing the vibration isolation table from coming into contact with the actuator on the installation floor side.

[0008]

In order to achieve the above-mentioned object, the present invention provides a vibration isolation table equipped with a vibration-disturbing device, an air spring for vertically supporting the vibration isolation table, and the vibration isolation device. A magnetic body fixed to the table, an electromagnet fixed to the installation floor side that controls the magnetic body by a magnetic attraction force, and a gap between the magnetic body fixed to the vibration isolation table and the electromagnet fixed to the installation floor side. A displacement sensor that detects the vibration, an acceleration sensor that is fixed to a vibration isolation table to detect the vibration, a control device that controls the pressure of the air spring by the signal of the displacement sensor, and a magnetic attraction of the electromagnet by the signal of the acceleration sensor. An anti-vibration device comprising a control device for controlling force, which is characterized by including a spring element for positioning in a horizontal direction.

Further, the spring constant of the spring element for positioning in the horizontal direction is less than ⅕ of the horizontal spring constant of the air spring.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION In a vibration isolation device for isolating microvibrations with an electromagnet, an air spring vertically supports and positions a mounted object on a vibration isolation table, and a coil spring having a small spring constant in the horizontal direction. Position with. As a result, even if the weight of the mounted object is large, the magnetic body on the vibration isolation table side is reliably positioned in the space where the electromagnet magnetic poles face each other, and contact is prevented. As a result, it is possible to prevent the problem that the electromagnet magnetic pole and the magnetic body come into contact with each other, and sufficient vibration isolation performance cannot be obtained, or the vibration isolation device or the mounted object is damaged in some cases.

Further, since the horizontal positioning is performed by a mechanically simple spring element, the horizontal electromagnet does not require a positioning force, and has a capacity necessary for controlling the vibration isolation. Therefore, the electromagnetic actuator can be small and have a small capacity.

Further, since the spring constant for positioning in the horizontal direction is as small as ⅕ or less in proportion to the horizontal spring constant of the air spring, the rigidity in the horizontal direction is weak and good vibration isolation characteristics are maintained. , Can be positioned.

[0013]

An embodiment of the present invention will be described below with reference to the accompanying drawings. FIG. 1 shows an elevation view of a vibration isolator according to an embodiment of the present invention, and FIG. 2 shows a plan view thereof. On the vibration isolation table 10, a mechanical device such as an electron microscope or a semiconductor manufacturing device that dislikes vibration is mounted. Vibration isolation table 10
Are vertically supported by air springs 11 at their four corners. The air spring 11 has one end fixed to a common base 12 fixed on the installation floor. Further, the vibration isolation table is provided with an acceleration sensor 13 that detects accelerations in the X and Y directions.

The air spring is positioned in the vertical direction by a signal from a displacement sensor (not shown) by a control device (not shown) for controlling pressure. The displacement sensor detects a gap between the magnetic pole of the electromagnet fixed on the installation floor side and the magnetic body fixed on the vibration isolation table side. The vibration detected by the acceleration sensor is controlled by controlling the exciting current of the electromagnet of the electromagnetic actuator 15 to control the magnetic attraction force exerted on the magnetic body facing the magnetic pole of the electromagnet, thereby eliminating the vibration on the vibration isolation table. Control. The vibration isolation control is performed by a control device (not shown).

In this embodiment, coil springs 16A, 16B and 16C for horizontal positioning are provided at six positions in the X, Y and θ directions as shown in the drawing. The horizontal position correction mechanism using the coil springs 16A, 16B and 16C is a member 1 provided on a common base on the installation floor side as shown in the drawing.
8 and a member 19 provided on the vibration isolation table 10 side are connected by a spring member 16. By providing this spring element in the X, Y, and θ directions, the spring force causes
The vibration isolation table 10 is positioned at a position that balances with the center of the electromagnet gap in the horizontal direction.

Therefore, when a large and heavy load (for example, several hundred kg) is placed on the vibration isolation table, the vertical positioning is performed by adjusting the pressure of the air spring, and the horizontal positioning is performed as described above. This is performed by the horizontal position correction mechanism 16 using the spring force. And the vibration isolation table 1
The vibration detected by the acceleration sensor 13 above 0 is controlled by controlling the magnetic attraction force of the electromagnetic actuator 15.

The higher the spring constant of the coil spring for horizontal positioning, that is, the larger the spring force, the easier the horizontal positioning becomes. However, the strong spring force means that the vibration isolation table and the installation floor side are strongly coupled, and when the installation floor itself vibrates, the vibration transmissibility of the vibration to the vibration isolation table deteriorates. Therefore, the vibration on the installation floor cannot be attenuated, and the vibration is directly transmitted to the vibration isolation table.
Further, it may be difficult to perform minute positioning.

Further, if the spring constant of the coil spring is extremely small, the vibration on the installation floor will not be transmitted to the vibration isolation table, but since the spring force for positioning in the horizontal direction is weak, the length pulled by the spring in the horizontal direction is large. Therefore, the operation space of the spring also becomes large. In some cases, the spring force is weak,
It may not be possible to position. In the vibration isolator of this embodiment, the spring constant of the coil spring for positioning in the horizontal direction is about 1 with respect to the spring constant of the air spring in the horizontal direction.
By setting / 5 or less, it is possible to perform fine positioning in the horizontal direction without increasing the rigidity in the horizontal direction.

In the above-mentioned embodiments, the coil spring is used as the spring element, but other types of spring elements are of course included in the spirit of the present invention.

[0020]

As described above, according to the present invention, the vibration isolation table is supported in the vertical direction by the air spring, the horizontal positioning is performed by the spring element, and the vibration generated on the vibration isolation table is generated by the electromagnetic actuator. It is a vibration isolation device to be removed. Therefore, in the vibration isolation device including the air spring, horizontal positioning can be easily performed without using a complicated actuator. Since it is positioned by a relatively weak spring element in the horizontal direction, the vibration isolation table supported by the air spring does not reduce the vibration isolation performance,
It is possible to prevent the vibration isolation performance from being deteriorated or damaged due to contact with the actuator on the installation floor side.

[Brief description of the drawings]

FIG. 1 is an elevation view of a vibration isolation device according to an embodiment of the present invention.

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

[Explanation of symbols]

 10 Vibration Isolation Table 11 Air Spring 13 Acceleration Sensor 14 Electromagnetic Actuator 16 Coil Spring 16A X-direction Positioning Coil Spring 16B Y-direction Positioning Coil Spring 16C θ-direction Positioning Coil Spring

Claims (2)

[Claims] 1. An anti-vibration table equipped with a vibration-disturbing device, and an air spring supporting the anti-vibration table in a vertical direction.
A magnetic body fixed to the vibration isolation table, an electromagnet fixed to the installation floor side for controlling the magnetic body by a magnetic attraction force, a magnetic body fixed to the vibration isolation table and an electromagnet fixed to the installation floor side A displacement sensor that detects the gap between the and, and an acceleration sensor that is fixed to the vibration isolation table and that detects the vibration,
A vibration isolator comprising a control device for controlling the pressure of an air spring by a signal of the displacement sensor and a control device for controlling a magnetic attraction force of an electromagnet by a signal of the acceleration sensor, which performs horizontal positioning. A vibration isolator comprising a spring element. 2. The vibration isolator according to claim 1, wherein the spring constant of the spring element for positioning in the horizontal direction is ⅕ or less of the spring constant of the air spring in the horizontal direction.