JPH06288432A - Vibration resistant device - Google Patents

Abstract

PURPOSE:To provide a vibration resistant device by magnetic floatation capable of damping vibration rapidly in the case of natural vibration being generated to a floating table mounted with machinery or the like. CONSTITUTION:A vibration isolator is provided with a floating table mounted with machinery detesting vibration; a magnetic yoke fixed to the floating table; a floating electromagnet fixed to an installation floor so as to support the magnetic yoke floatingly in the contactless state by magnetic force; a displacement sensor for measuring a clearance between the floating electromagnet and the magnetic yoke; and a controller formed of a compensating circuit for outputting the exciting current of the floating electromagnet on the basis of the output from the displacement sensor, and a power amplifier. In this vibration resistant device thus supporting the floating table floatingly in the contactless state, the floating table is of such structure that plural plates 21, 22, 23 are overlapped and integrated by fastening means 24 allowing the relative slide of the respective plates.

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 more particularly to an anti-vibration device for removing vibrations from a floor by suspending a levitation table equipped with a mechanical device which is not susceptible to vibrations by magnetic force.

[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 installed in a vibration isolator and installed in a factory or the like. As a conventional vibration isolation device,
An anti-vibration device using magnetic levitation that can realize high-performance anti-vibration has been developed in place of the air spring and rubber that have been used for a long time, and the details thereof are disclosed in, for example, Japanese Patent Laid-Open No. 2-203040.

FIG. 3 shows an example of such a magnetic levitation vibration isolator. On the levitation table 1, mechanical devices such as an electron microscope and a semiconductor manufacturing device, which are extremely reluctant to vibrate, are mounted (not shown). ), Is held in a non-contact floating state by the electromagnetic actuator 2. Therefore, even if the installation floor on which the electromagnetic actuator 2 is installed vibrates due to an earthquake or the like,
Vibration is not transmitted to the levitation table 1 that is levitationally held in a non-contact manner, and mechanical devices and the like that are extremely reluctant to vibration are not affected by the vibration of the installation floor.

FIG. 4 is an explanatory view of an electromagnetic actuator of the vibration isolator. The magnetic yoke 3 is fixed to the levitation table 1 which mounts a device for vibration isolation. Installation floor 6
The levitation electromagnet 4 fixed to the above supports the magnetic yoke 3 to which the vibration isolation table 1 is fixed by the magnetic attraction force in a non-contact manner. The gap between the magnetic pole of the levitation electromagnet 4 and the magnetic yoke 3 as a target is measured by the displacement sensor 5. The controller 7 includes a compensating circuit 9 and a power amplifier 10, and based on the output from the displacement sensor 5, the levitation electromagnet so that the vibration isolation table 1 to which the magnetic yoke 3 is fixed is stably levitationally supported at a target position. The excitation current of 4 is controlled.

In such a conventional vibration isolator, a honeycomb table made of an aluminum material is generally used as the floating table. This is because an electron microscope, which is extremely reluctant to vibrate, and a mechanical device etc. mounted on a levitation table such as a semiconductor manufacturing device generally have a heavy weight, and a rigidity for supporting the weight is required, and a magnetic levitation load is required. This is because the floating table itself needs to be as light as possible in order to reduce the number.

[0006]

However, although the levitation table of the magnetic levitation type vibration isolation device can be manufactured to have a lightweight and high rigidity due to the honeycomb structure, its vibration damping action is small because of its high rigidity. An oscillation phenomenon may occur in the levitation control, which may deteriorate the vibration isolation performance. That is, a mechanical device such as an electron microscope mounted on the levitation table constitutes a mechanical vibration system that is determined by its mass and elastic coefficient together with the levitation table. Even if the levitating table is levitated from the installation floor, if vibration occurs in the system of the levitating table equipped with mechanical devices due to some disturbance, the damping force does not work against this vibration and the vibration continues forever. Become.

In view of the problems of the prior art, the present invention provides a vibration isolator capable of quickly damping the vibration of a vibration system of a floating table on which a mechanical device is mounted.

[0008]

A levitation table according to the present invention is characterized in that a plurality of plate members are stacked and integrated by a fastening means that allows relative sliding of the plate members.

Further, the levitation table according to the present invention is characterized in that a damping steel sheet having a multilayer structure including flat plates of viscoelastic material is used for the upper and lower flat plates sandwiching the honeycomb core material.

[0010]

With the floating table, a plurality of plates are stacked and fastened by fastening means that allows relative sliding of the plates, so that when a vibration occurs on the floating table on which the mechanical device is mounted, a plurality of plates can be used. Since the floating table in which the plate materials are stacked allows the relative slippage of each plate material, a sliding action occurs between the plate materials. A mechanical frictional force is generated by the sliding motion of the plate material, and damping (damping) can be applied to the vibration generated in the floating table system.

Further, by using the damping steel plates containing the viscoelastic material on the upper and lower flat plates sandwiching the honeycomb core material in the floating table, the viscoelastic material such as rubber similarly damps the vibration generated in the floating table system. be able to.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS In the vibration isolator of the present invention, the mechanism for holding the levitation table by the magnetic attraction force of the levitation electromagnet is the same as that of the conventional vibration eliminator shown in FIGS. Is omitted.

FIG. 1 is an explanatory view of the structure of a floating table according to the first embodiment of the present invention. (A) shows the stationary state of the floating table, and (B) shows the elastically deformed state of the floating table. As shown in the figure, the floating table 1 includes an upper plate 22, a honeycomb core member 21, and a lower plate 23 that are stacked on top of each other and fixed by bolts 24 that are fastening means that allow relative sliding of the respective plate members. Therefore, when the floating table vibrates, as shown in (B), elastic deformation occurs and slip occurs between the plate members. Therefore, on the contact surface of each plate member, sliding friction occurs due to the deformation of the plate member, and the elastic energy of the deformation can be dissipated. As the plate material of the upper plate 22 and the lower plate 23, for example, a stainless steel plate is used.

FIG. 2 shows the structure of a floating table according to the second embodiment of the present invention. The floating table 1 has a structure in which a damping steel plate 25 having a multilayer structure including a flat plate 26 made of an elastic material such as rubber is fixed to an upper plate and a lower plate sandwiching a honeycomb core material 21. The honeycomb core material 21 is a plate material having a honeycomb structure such as an amyl similar to that shown in the related art. The vibration damping steel plates 25 of the upper plate and the lower plate are, for example, flat plates of viscoelastic material such as rubber sandwiched by steel plates, and the vibration is damped by the viscoelastic material absorbing the vibration. Is.

Therefore, when some disturbance occurs in the mechanical vibration system composed of the levitation table on which a mechanical device that dislikes vibration is mounted, vibration of the natural frequency of this vibration system occurs. Viscoelastic material 26 included in damping steel plate 25
By absorbing the vibrations, the elastic energy of the vibrations is dissipated, so that the vibrations can be quickly damped.

[0016]

As described above, the floating table of the vibration isolator of the present invention uses a fastening means that allows a plurality of plate members to be stacked and allows relative sliding of the plate members, or a honeycomb core member to be sandwiched. The upper and lower flat plates are made of damping steel plates containing a viscoelastic material. Therefore, when vibration occurs due to some disturbance to the mechanical vibration system composed of the mechanical device mounted on the levitation table and the levitation table, as friction energy of relative slip of each plate material, or viscous Vibration can be quickly absorbed as the deformation energy of the elastic material. Therefore, the levitation table of the present invention can enhance the vibration damping function against disturbance vibration, and as a result, realize a high-performance vibration isolator that can easily perform levitation control.

[Brief description of drawings]

FIG. 1 is an explanatory diagram of a structure of a floating table according to a first embodiment of the present invention.

FIG. 2 is an explanatory diagram of a structure of a floating table according to a second embodiment of the present invention.

FIG. 3 is a perspective view of a vibration isolation device.

FIG. 4 is an explanatory diagram of an electromagnetic actuator.

[Explanation of symbols]

 1 Floating table 2 Electromagnetic actuator 3 Magnetic yoke 4 Electromagnet for levitation 5 Displacement sensor 6 Installation floor 7 Controller 9 Compensation circuit 10 Power amplifier 21 Honeycomb core material 22 Upper plate 23 Lower plate 24 Bolt 25 Damping steel plate 26 Viscoelastic material

Claims (2)

[Claims] 1. A levitation table equipped with a vibration-disturbing device, a magnetic yoke fixed to the levitation table, and a levitation fixed to an installation floor for levitationally supporting the magnetic yoke without magnetic contact. An electromagnet, a displacement sensor that measures a gap between the levitation electromagnet and the magnetic yoke, a compensation circuit that outputs an exciting current of the levitation electromagnet based on an output from the displacement sensor, and a power amplifier. In a vibration isolation device comprising a controller and supporting the floating table in a non-contact manner, the floating table comprises a stack of a plurality of plate members,
An anti-vibration device having a structure integrated by a fastening means that allows relative sliding of each plate material. 2. A levitation table equipped with a vibration-disturbing device, a magnetic yoke fixed to the levitation table, and a levitation fixed to an installation floor for levitationally supporting the magnetic yoke without magnetic contact. An electromagnet, a displacement sensor that measures a gap between the levitation electromagnet and the magnetic yoke, a compensation circuit that outputs an exciting current of the levitation electromagnet based on an output from the displacement sensor, and a power amplifier. In a vibration isolator that includes a controller and floats and supports the floating table in a non-contact manner, the floating table uses a vibration damping steel plate having a multilayer structure including flat plates of viscoelastic material for upper and lower flat plates sandwiching a honeycomb core material. An anti-vibration device, which is characterized in that