JPH10196716A - Active damping device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make damping performance in a continuous tremor and base isolation performance in an earthquake compatible by providing a bearing ball and a rubber member as a vibration barrier member for an actuator member of an active damping member which is located in parallel to a passive damping member consisting of a spring and a vibration damping member. SOLUTION: If external force to cause floor vibration is applied, a surface plate 6 supported by an active damping member vibrates in a horizontal direction. Therefore, the output signal of a detector which detects the acceleration or displacement in vertical direction at each point of the surface plate 6 where an actuator member 5 is placed as well as the acceleration in horizontal direction of equipment to be controlled, etc., is used when a processor drives the actuator member 5 so that the relative displacement between an electron gun and sampling is restricted and the blur of an image is prevented. Against horizontal ground vibration due to the occurrence of an earthquake on the other hand, the distortion of a passive damping member 4 exerts an base isolation function. Against vertical ground vibration, a vibration barrier member 26 of the actuator member 5 eases the load applied to a laminated piezoelectric element 24.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an active vibration isolator.

[0002]

2. Description of the Related Art In precision equipment such as an electron microscope,
Generally, since the image accuracy or performance may be deteriorated due to vibration of the floor on which the device is installed, the device is installed on a surface plate supported by a vibration isolator. An anti-vibration device is a combination of a spring member of an elastic body having low rigidity in a horizontal direction and a vertical direction, for example, a combination of a coil spring, an air spring, or a vibration-proof rubber and a vibration damping member such as a viscous damper having a damping effect. Often used. An anti-vibration device is a device that reduces (vibrates) the absolute acceleration of the response of a surface plate and devices mounted on the surface plate by isolating vibrations from the floor surface. However, a passive vibration isolator always has a natural frequency, and there is a limit in reducing the natural frequency. Generally, the natural frequency of the passive vibration isolator is about 1 to 3 Hz, and the vibration isolation effect of the passive vibration isolator cannot be obtained with respect to the floor vibration of 1.5 to 4 Hz or less. This is a problem of the passive vibration isolator.

In order to solve such a problem, a method of actively suppressing the vibration of the surface plate with respect to the minute vibration of the floor vibration can be considered. As described in Japanese Patent Application Laid-Open No. 1-307537 and Japanese Patent Application Laid-Open No. 2-228712, an active device that uses an actuator to feedback the absolute acceleration and the like on the surface plate to actively suppress the absolute acceleration of the vibration of the surface plate. There is a vibration isolation device.

[0004]

According to the principle of the prior art in an active vibration isolator, the effect of greatly reducing the vibration of the surface plate on which the equipment is mounted against the floor vibration can be obtained.
However, for large floor vibrations such as in the case of an earthquake,
It cannot be handled by the stroke of the actuator of the active vibration isolator. This is because the required stroke of the actuator of the active vibration isolator for an earthquake is of the order of cm, while the vibration level of the floor vibration due to the always fine vibration, which is usually a problem, is of the order of cm. Since the displacement resolution of the actuator and the maximum displacement generated during an earthquake are different on the order of 10 ⁴ or more, only a limited number of actuators are compatible with this. It will be expensive.

An object of the present invention is to provide an inexpensive active anti-vibration apparatus which has both vibration isolation performance against microtremors and seismic isolation performance against seismic motion.

[0006]

Means for Solving the Problems Earthquake motion acts in the horizontal and vertical directions, but it is the horizontal direction that seriously damages equipment and structures, and generally the acceleration level in the vertical direction is 1 / horizontal of the horizontal direction. About 2.

[0007] In order to achieve the above object, the present invention provides the first invention so that seismic isolation performance can be exhibited even during an earthquake.
A passive vibration isolator consisting of a spring member and a vibration damping member, which has a longer natural period determined in consideration of a device to be mounted and which can tolerate a large relative displacement, is provided in parallel with the passive vibration isolator (for the vertical direction). A) a bearing ball member is provided on the actuator member, which is a component of the active vibration isolating member, so as not to receive a horizontal load from a surface plate supported by the actuator member; According to a second aspect of the present invention, a support member and a spring member capable of large horizontal displacement and a vibration damping member for reducing relative displacement are provided in series with the active vibration isolator. A stopper member for restraining horizontal displacement to a passive vibration isolation member of the active vibration isolation device, and an actuator for the active vibration isolation member. Similar to the first invention to the wood, providing the ball bearing member and the vibration isolating member.

In general, in a precision instrument such as an electron microscope, only relative displacement between members of the instrument, such as between an electron gun or an objective lens and a sample, is measured with high accuracy, not the absolute acceleration of the instrument itself. What is necessary is just to be able to reduce. Therefore, in the present invention, in particular, the detector of the accelerometer for detecting the horizontal vibration state of a plurality of points of the surface plate and the device and the vertical direction of each point on the surface plate where the actuator members for the vertical direction are arranged By using the signal from the accelerometer or displacement meter detector to detect the vibration state of the actuator, the controller controls the actuator member for the vertical direction, so that the absolute acceleration in the vertical direction and the internal structure of the device in question The inclination of the surface plate can be suppressed so as to suppress the horizontal relative acceleration or relative displacement between the member and the sample table.

On the other hand, when the seismic motion occurs, in the first invention, the spring member of the passive vibration isolating member and the vibration damping member are arranged so that the horizontal displacement is not restricted by the ball bearing member provided on the actuator member of the active vibration isolating member. The member can exert a horizontal seismic isolation function.
Also, with respect to the vertical seismic motion, a large shock is not applied to the actuator member by the vibration isolating member.

In the second invention, when a seismic motion is generated, the horizontal displacement of the active vibration isolator is restrained by the stopper member provided on the passive vibration isolator of the active vibration isolator. The seismic isolation device provided in series with the active anti-vibration device moves in the horizontal direction by the horizontal movement member, exerts the seismic isolation effect, and the restoring force is applied by the spring member. And horizontal displacement is suppressed. When a sliding member is used as the horizontal moving member, the effect of suppressing horizontal displacement is further increased.
It acts on vertical seismic motion in the same way as in the first invention.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Some embodiments of the present invention will be described below with reference to the drawings.

First, an embodiment of the present invention will be described with reference to FIGS.

The embodiment shown in FIG. 1 is an example in which the active anti-vibration apparatus of the present invention is applied to an electron microscope apparatus 17. In this embodiment, a plurality of active vibration isolation members 3 are provided on an installation plate 2 installed on a floor 1. As shown in FIG. 2, the active vibration isolation member 3 includes a passive vibration isolation member 4 having a vibration isolation effect in the horizontal and vertical directions, and a vertical actuator member 5 provided in parallel with the passive vibration isolation member. . The plurality of active vibration isolation members 3 support the surface plate 6. Further, an electron microscope device 17 is mounted on the surface plate 6. Actuator member 5 of active vibration isolation member 3
For example, as shown in FIG. 1, the vertical acceleration of the installation plate 2 and the vertical acceleration or displacement of a point on the surface plate 6 supported by the active vibration isolation member 3 are detected as shown in FIG. Detector 7 and electron microscope device 17 to be controlled
A plurality of detectors 7 for detecting horizontal acceleration and the like for grasping the vibration of the main body are provided as necessary. The signals from these detectors 7 are input to A /
The program is input to a DSP (Digital Signal Processor) member 11 through the D converter 10, and an execution program for controlling the actuator member 5 of the active vibration isolation member 3 is written in the DSP member 11. The signal calculated at high speed controls the actuator member 5 via the D / A converter 12 and the amplifier 13.

Next, an embodiment of the active vibration isolator 3 of the present invention will be described with reference to FIG. The active anti-vibration member 3 mainly includes a passive anti-vibration member 4 and a vertical actuator member 5 provided in parallel with the passive anti-vibration member 4. In this embodiment, both ends of the spring member 19 are connected to the pedestal members 18a and 18a.
b, and a viscoelastic body 20 having a damping function is arranged at the center of the spring member 19. The basic structure of the actuator member 5 is a multilayer piezoelectric element 24, a cylindrical support member 21 and a screw member 22, a vibration isolation member 26, and a ball bearing member 28 used for adjusting the height of the multilayer piezoelectric element 24. Receiving member 2 supported from below
7 The laminated piezoelectric element 24 has block members 3 at both ends.
5 and a cover member 25 are attached, and the lower block member 23 is supported by a screw member 22.
Is rotated, the height of the laminated piezoelectric element member 24 can be adjusted, so that the screw member 22 causes the ball bearing member 28 provided above the actuator member 5 to apply an appropriate load to the surface plate 6. Pressed until supported. Further, the vibration isolating member 26 is used to remove a high frequency component outside the control object of the floor vibration, and also to prevent a shocking vertical load received during an earthquake from being applied to the laminated piezoelectric element member 24. Used for The cover member 25 is provided to protect the laminated piezoelectric element 34.

The operation of this embodiment will be described with reference to FIGS.

First, in the case of a floor vibration external force, the surface plate 6 supported by the active vibration isolating member 3 and the main body of the electron microscope apparatus 17 are vibrated in horizontal and vertical directions. Since the platen 4 is not supported by the center of gravity, a vibration mode inclined with respect to the horizontal plane is applied to the platen 4. As a result, for example, a horizontal relative displacement tends to occur between the electron gun in the electromagnetic lens holder and the sample stage. At this time, the output signal of the detector 7 for detecting the vertical acceleration or displacement of each point of the surface plate 6 on which the actuator member 5 is disposed, the horizontal acceleration of the electron microscope device 17 to be controlled, and the like are A The DSP member 11 is input to the DSP member 11 through the / D converter 10, and the DSP member 11 instantaneously calculates a voltage corresponding to the control force of the actuator member 5, and the calculated control voltage is converted by the D / A converter 12 and the amplifier. By driving the actuator member 5 through 13, the relative displacement between the electron gun and the sample can be suppressed, and image blur can be prevented.

Next, when an external force is generated, a large horizontal displacement of the platen 6 is not restrained by the ball bearing member 28 of the actuator member 5 against the horizontal seismic motion. By deforming 4, the seismic isolation function can be exhibited. At this time, excessive horizontal displacement is suppressed by the viscoelastic member 20. In addition, with respect to the vertical earthquake motion, the vibration load applied to the laminated piezoelectric element member 24 can be reduced by the vibration blocking member 26 of the actuator member 5. The detector 7 or the surface plate 6 provided on the installation plate 2
When the vibration amount equal to or more than a certain allowable value is detected by the detector 7 or the like provided above, the control of the laminated piezoelectric element member 24 from the DSP member 11 may be stopped.

Next, FIG. 3 shows a second embodiment. The embodiment of FIG. 3 is different from the embodiment of FIG. 2 in that an inner cylindrical member 29a and an outer cylindrical member 29b are provided so as to surround the spring member 19,
The buffer member 30 is provided in a portion where the two cylindrical members 29 come into contact, in this figure, inside the outer cylindrical member 29b.
This is because when the external force of the earthquake exceeds the allowable displacement of the passive vibration isolation member 4, the inner cylindrical member 29a
By being received by the buffer member 30 provided inside 9b, a large impact force is not applied to the precision equipment mounted on the surface plate. Further, the outer cylindrical member 29b in FIG. 3 may be filled with a high-viscosity fluid 38 to achieve a vibration damping effect.

FIGS. 4 and 5 show a vertical sectional view and a horizontal sectional view of the third embodiment. A plurality of active vibration isolation members 3 supporting a surface plate 6 on which precision equipment such as an electron microscope device is mounted.
The installation board 2 on which the installation board 2 is installed is divided, and a horizontal moving member 32 is provided below each of the installation boards 2 so that the installation board 2 moves horizontally on the bottom board 31 provided between the installation board 2 and the floor 1. You can move to. Further, a fixing member 33 for fixing an end of a coil spring member 34 which is a seismic isolation element is provided. As shown in FIG. 5, the coil spring member 34 provided on the facing installation plate 2 is connected by a wire member 35. The central portion of the wire member 35 is supported by a support bar member 36 attached to the bottom plate 31 so that the wire member 35 can move in the axial direction and is restrained in the perpendicular direction. Also, the horizontal gap between the stopper member formed of the inner and outer cylindrical members 29 provided on the passive vibration isolator 3 of the active vibration isolator 3 is made small enough not to hinder the micro vibration. In this embodiment, when a horizontal seismic external force is applied, the horizontal displacement of the active vibration isolating member 3 is restrained by the stopper member provided on the passive vibration isolating member 4, and the active vibration isolating member 3 is provided on the installation plate 2 by the seismic force. The installation plates 2 move on the bottom plate 31 in the same direction by the horizontal moving members 32. For example, in FIG. 5, when the four installation plates 2 move rightward on the paper surface, the wire members 35b and 3
5d is restrained by the support rod members 36b and 36d,
By extending the coil spring member connected to the wire members 35b and 35d, a restoring force in the left direction on the paper is given to the installation plate 2. Conversely, when the installation plate 2 moves to the left on the paper, the wire members 35b and 35d
Is restrained by the support rod members 36b and 36d, and the coil spring member connected to the wire members 35b and 35d is extended, so that the installation plate 2 is given a restoring force in the rightward direction of the drawing. In these cases, the wire member 3
5a and 35c are not restricted by the support rod members 36a and 36c, and the coil spring members connected to the wire members 35a and 35c are not extended, and no spring force is generated. When the installation plate 2 moves in the vertical direction, the wire members 35a and 35c are restrained by the support rod members 36a and 36c, and each installation plate 2 is given a restoring force in a direction opposite to the moving direction. Due to this restoring force, the horizontal displacement of the installation plate 2 is suppressed, and after the earthquake, the installation plate 2 and the precision instruments supported by these are returned to their original positions.

FIGS. 6 and 7 show a vertical sectional view and a horizontal sectional view of the fourth embodiment. A plurality of active vibration isolation members 3 supporting a surface plate 6 on which precision equipment such as an electron microscope device is mounted.
Horizontal moving member 32 provided at the lower part of the installation plate 2 for installing
Is arranged in the dish member 37 provided on the floor 1 so that the horizontal moving member 32 can move horizontally on the bottom member of the dish member. As shown in FIG. 7, both ends of a coil spring member 34 that applies a restoring force to the installation plate 2 are connected to the wire members 5, and the other ends of the respective wire members 35 are fixed to the facing horizontal moving member 32. Further, these wire members 35 are supported by being sandwiched between two roller members 39 fixed to a wall member around the dish member 37. The space between the resistance member 40 provided on the horizontal moving member 32 and the bottom member of the plate member 37 is filled with a highly viscous fluid 38. In this embodiment, when a horizontal earthquake external force is applied, the horizontal displacement of the active vibration isolating member 3 is restrained by the stopper member provided on the passive vibration isolating member 4 and the horizontal moving member 32 provided on the installation plate 2. Thereby, each installation plate 2 moves on the bottom member 41 of the dish member 37 in the same direction. For example,
In FIG. 7, when the installation plate 2 moves rightward on the paper,
Since the wire members provided at both ends of each of the coil spring members 34b and 34d are partially restrained from moving in the right direction on the paper by the roller members supporting these wire members, the coil spring members 35b and 35d By extending, the restoring force in the left direction on the paper is given to the installation plate 2 via the horizontal moving member 32. Conversely, when the installation plate 2 moves to the left on the plane of the paper, the coil spring members 35b and 35d are extended and the horizontal movement member 32 is applied to the installation plate 2 this time. Provides resilience. In these cases, the coil spring members 34a and 3
Since the wire members provided at both ends of 4c are not restrained by the roller members supporting them, the coil spring members 34a and 34c are not extended, and no spring force is generated. When the installation plate 2 moves in the vertical direction, the wire members provided at both ends of the coil spring members 34a and 34c are restrained by the roller members, and each installation plate 2 is restored in the direction opposite to the moving direction. Power is given. With this restoring force, the horizontal displacement of the installation plate 2 is suppressed,
After the earthquake, the installation plates 2 and the precision equipment supported by them are returned to their original positions. Further, when the horizontal moving member 32 moves, the high-viscosity fluid 38 between the resistance member 40 provided on the horizontal moving member 32 and the bottom member of the plate member 37.
Thereby, since the shear viscous resistance acts on the resistance member, there is an effect of suppressing the horizontal displacement.

[0021]

According to the present invention, in the active vibration isolating member provided with the passive vibration isolating member and the vertical actuator member in parallel, the passive vibration isolating member is used as a seismic isolation member. By providing the seismic isolation members in series, it is possible to provide an active anti-vibration device that can prevent damage to precision equipment due to an external earthquake force.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view of an embodiment in which an active vibration isolation device of the present invention is applied to an electron microscope device.

FIG. 2 is a longitudinal sectional view of an embodiment of an active vibration isolating member using the passive vibration isolating member of the present invention as a seismic isolation member.

FIG. 3 is a longitudinal sectional view of an embodiment of an active vibration isolating member using the passive vibration isolating member of the present invention as a seismic isolation member.

FIG. 4 is a sectional view of an embodiment in which a seismic isolation member is provided in series with an active vibration isolation member.

FIG. 5 is a sectional view of an embodiment in which a seismic isolation member is provided in series with an active vibration isolation member.

FIG. 6 is a sectional view of another embodiment in which a seismic isolation member is provided in series with an active vibration isolation member.

FIG. 7 is a sectional view of another embodiment in which a seismic isolation member is provided in series with an active vibration isolation member.

[Explanation of symbols]

2. Arrangement plate, 4. Passive vibration isolation member, 5: Active vibration isolation member, 6: Surface plate, 18: Pedestal member, 19: Coil spring member, 20: Viscoelastic member, 21: Cylindrical support member, 22 ...
Screw member, 23: Block member, 24: Laminated piezoelectric element, 25: Cover member, 26: Vibration blocking member, 27: Bearing receiving member, 28: Ball bearing.

Claims (1)

[Claims] 1. A passive vibration isolation member comprising a spring member and a vibration damping member provided between a floor and a surface plate on which equipment is mounted, a vertical actuator member, and a detection device provided for controlling the same. In an active vibration isolator comprising a vessel and a controller, the passive vibration isolation member and the vertical actuator member are arranged in parallel, so that the vertical motion of the surface plate is not restricted by the vertical actuator member. An active vibration isolator comprising a ball bearing member and an elastic vibration blocking member.