JPH10196717A - Base isolation device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To eliminate a coil spring or a gas spring and enable base isolation operation even in microscopic vibration by providing an upper base for loading the items to be protected from vibration and a lower base for supporting the upper base while allowing its movement, and restoring the upper base to the specified position on the lower base using an actuator when the base isolation operation is complete. SOLUTION: In a base isolation device 1 on which items to be protected from vibration such as a work of art are placed, spherical bearings 6a-6d provided on the upper face of a lower base 5 support an upper base rocking-free. Two or more upper pullies 8a-8h provided to the lower face of an upper base and two or more lower pullies 9a-9d provided on the upper face of the lower base 5, are so placed as to form an identical loop, and a wire 12 is laid through these pullies 8a-8h and 9a-9d. One end 12a of the wire 12 is hooked on a hook rod 13 and the other end 12b is connected to a rod 14a of an actuator 14, and when the base isolation operation is complete, the actuator 14 moves the upper base back to the specified position on the lower base 5.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a seismic isolation device, and more particularly to a seismic isolation device configured to reduce the resistance at the start of seismic isolation operation so that seismic isolation operation can be performed well even when relatively small vibration is transmitted. Related to seismic device.

[0002]

2. Description of the Related Art Conventionally, precision equipment such as a semiconductor exposure apparatus or an art object such as a Buddha image is susceptible to vibration, and is therefore installed so as to be supported by a seismic isolation device. This type of seismic isolation device is installed on the floor with an upper base on which objects are placed to prevent collapse of seismically isolated objects such as precision equipment when vibrations mainly due to earthquakes are propagated. It is configured to be able to be relatively displaced with respect to the lower base. That is, when the vibration caused by the earthquake is propagated to the lower base, even if only the lower base vibrates, the upper base is relatively displaced, and the upper base and the base-isolated object are supported as if they seem to be almost stationary.

[0003] Between the upper base and the lower base,
A coil spring is stretched, and when the upper base and the lower base are relatively displaced, the bases of the bases are returned to the origin positions where the centers of the bases are opposed to each other by the spring force of the coil spring. In addition to the above, a wire is stretched between an upper pulley provided on the lower surface of the upper base and a lower pulley provided on the upper surface of the lower base, one end of the wire is fixed, and the other end of the wire is a gas spring. Is connected to a rod. In the case of this seismic isolation device, the urging force of the gas spring acts as wire tension, the upper base and the lower base are relatively displaced, and the rod of the gas spring is pulled out to increase the wire tension. The spring force of the gas spring is set so that the wire tension is minimized when returning to the position.

[0004]

However, in the conventional seismic isolation device, the vibration caused by the earthquake can be isolated by the relative displacement between the upper base and the lower base, but the coil spring or the gas for returning the base to the origin position can be used. When the vibration smaller than the spring force of the spring is propagated, the upper base and the lower base are not relatively displaced, and the vibration propagates to the precision equipment which is the seismically isolated object.

[0005] In this case, despite the fact that the precision equipment is supported by the seismic isolation device, a minute vibration from the floor propagates to the precision equipment, and the precision of the precision equipment is disturbed. There is a problem that it becomes impossible. In addition, if the spring force of the coil spring or gas spring is set small so that seismic isolation can be achieved even with minute vibrations, the upper base cannot return to the home position after the end of the seismic isolation operation. The stroke becomes short. Also, if the spring force of the coil spring or gas spring is too small, when a large vibration is propagated, the spring force of the coil spring or gas spring is weak and the maximum amplitude of the relative displacement between the upper base and the lower base is allowable. May reach the stroke limit, and the seismic isolation operation cannot be performed any more.

Therefore, an object of the present invention is to provide a seismic isolation device which solves the above-mentioned problems.

[0007]

In order to solve the above problems, the present invention has the following features. Claim 1
The invention of the above is a seismic isolation device comprising an upper base on which a seismic isolated object is placed, and a lower base movably supporting the upper base. An actuator for returning to a predetermined position is provided.

Therefore, according to the first aspect of the invention, after the seismic isolation operation is completed, the upper base can be returned to a predetermined position on the lower base by driving the actuator. It is not necessary to provide a vibration, and the seismic isolation operation can be performed even with a small vibration that cannot be isolated because the spring force of the coil spring or the gas spring becomes a resistance at the start of the seismic isolation operation.

According to a second aspect of the present invention, there is provided the seismic isolation device according to the first aspect, wherein, during the seismic isolation operation, a resistance force corresponding to a displacement of the upper base with respect to the lower base or an acceleration of the upper base. Is driven between the upper base and the lower base.

Therefore, according to the second aspect of the present invention, during the seismic isolation operation, the actuator drives the upper base to displace the upper base with the lower base or to generate a resistance force corresponding to the acceleration of the upper base between the upper base and the lower base. In order to provide, the relative displacement between the upper base and the lower base is suppressed, and the displacement of the upper base is suppressed so that the amplitude between the upper base and the lower base does not exceed a stroke limit which is an allowable maximum displacement. be able to.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to the drawings. FIG. 1 shows a first example of the seismic isolation device according to the present invention.
FIG. 2 is a front view of the embodiment, and FIG. 2 is a plan view of the seismic isolation device. still,
FIG. 2 shows a state in which the upper base is removed so that the internal configuration of the seismic isolation device can be understood.

A seismic isolation device 1, such as a computer or a work of art, is placed on the seismic isolation device 1. The seismic isolation device 1 is installed on a foundation 3, and the object 2 is mounted on the upper base 4 of the seismic isolation device 1. The upper base 4 is provided so as to be swingable in a horizontal direction with respect to a lower base 5 fixed to the base 3.

That is, spherical bearings 6a slidably contacting the lower surface of the upper base 4 are provided at the four corners of the upper surface of the lower base 5.
To 6d are provided. Each spherical bearing 6a-6d
Is provided at the upper end of the column 7. Therefore, the spherical bearings 6a to 6d regulate the height position of the upper base 4 and support the upper base 4 in a swingable manner.

A plurality of upper pulleys 8a are provided on the lower surface of the upper base 4.
8h are arranged at predetermined intervals in a substantially square loop shape, and the upper pulleys 8a to 8h are provided at four corners on the upper surface of the lower base 5.
A plurality of lower pulleys 9a to 9d are rotatably provided at intervals so as to form the same loop as 8h.

That is, the upper pulleys 8a to 8i and the lower pulley 9a
9d are disposed inside the spherical bearings 6a to 6d, and are supported by shafts 10 and 11 arranged at predetermined intervals on the upper base 4 and the lower base 5.
The upper pulleys 8a to 8i and the lower pulleys 9a to 9d are rotatably supported at the ends of the shafts 10 and 11 so as to be located at the same height (same plane).

The upper pulleys 8a to 8i and the lower pulleys 9a to 9i
9d is disposed in a substantially rectangular loop shape, and is provided so as to be substantially the same for each side. Upper pulleys 8a to 8i and lower pulleys 9a to 9 arranged as described above
In h, the wire 12 is mounted in a loop shape. One end 12a of the wire 12 is locked by a locking rod 13 rising from the lower base 5, and the other end 12b is connected to an actuator 14
Is connected to the rod 14a.

The actuator 14 is a linear drive type motor comprising a cylindrical electromagnetic coil 14b and a rod-shaped magnet 14c slidably inserted into the electromagnetic coil 14b. Supported. The end of the magnet 14c is connected to the rod 14a to which the wire 12 is connected. Actuator 1
4 indicates that when no voltage is applied to the electromagnetic coil 14b, no driving force is generated for the magnet 14c, and when a voltage is applied to the electromagnetic coil 14b, the magnet 14c is attracted in the direction A and the wire 12 Can be increased in tension.

In this embodiment, since the linear drive type actuator 14 is disposed in a direction extending in the horizontal direction inside the loop of the wire 12, space saving and thinning are achieved. Further, in a conventional seismic isolation device having a coil spring or gas spring for returning the base, when vibration smaller than the spring force of the coil spring or gas spring is propagated, the upper base 4 and the lower base 5 are displaced relative to each other. Without this, there is a problem that the vibration propagates to the base-isolated object 2.

However, in the seismic isolation device 1, since the coil spring or the gas spring for returning the upper base 4 to the origin position where the center of the upper base 4 coincides with the center of the lower base 5 is not provided, the seismic isolation operation is performed. At the start, the seismic isolation operation can be performed even with a small vibration that cannot be seismically isolated because the spring force of the coil spring or the gas spring becomes a resistance.
Therefore, the seismic isolation device 1 can perform the seismic isolation operation so that the seismic isolated object 2 is not affected by the micro-vibration even if it is a precision instrument or the like that is easily affected by the micro-vibration.

Further, since the actuator 14 is driven after the seismic isolation operation is completed to apply tension to the wire 12, the upper base 4 can be returned to a predetermined position (origin position) of the lower base 5, and The stroke at the start of seismic isolation operation can be secured. Further, the actuator 14 is provided with an acceleration sensor 16 which outputs a sensor signal according to the magnitude of the acceleration of the upper base 4 itself when the relative displacement between the upper base 4 and the lower base 5 becomes equal to or more than a predetermined value. In order to drive and control the actuator 14 according to the magnitude of the sensor signal output from the displacement sensor 17 that outputs a sensor signal according to the magnitude of the relative displacement with respect to the base 5, the vibration of the upper base 4 is attenuated, It is possible to prevent the amplitude (the amount of relative displacement) between 4 and the lower base 5 from exceeding the stroke limit which is the maximum allowable displacement.

In the conventional seismic isolation device, when the vibration input by the spring constant of the coil spring or gas spring for returning the upper base 4 to the origin position matches the natural frequency of the coil spring or gas spring, There was a risk that the spring would resonate. However, in this embodiment, since the coil spring or gas spring for returning to the origin is not provided, the configuration is such that the above-described resonance phenomenon does not occur.

An acceleration sensor 15 detects the acceleration of the lower base 5. This acceleration sensor 15 is a lower base 5
Is stationary, the output is zero, but the vibration from the base 3 is propagated to the lower base 4 and a signal corresponding to the acceleration of the lower base 5 is output.

An acceleration sensor 16 detects the acceleration of the upper base 4. The acceleration sensor 16 has an upper base 4
Is stationary, the output is zero, but the upper base 4
And outputs a signal corresponding to the acceleration of the upper base 4. Reference numeral 17 denotes a displacement sensor that detects the displacement of the upper base 4. The output of the displacement sensor 17 is zero when the upper base 4 is stationary at the origin position where the center of the upper base 4 is opposed to the center of the lower base 5. When displaced, a signal corresponding to the displacement of the upper base 4 is output.

Reference numeral 18 denotes a control device for driving and controlling the actuator 14. In the memory of the control device 18, when the relative displacement between the upper base 4 and the lower base 5 exceeds a predetermined value, the drive of the actuator 14 is controlled in accordance with the magnitude of the signal output from the acceleration sensor 16 or the displacement sensor 17. To attenuate the vibration of the upper base 4 and after the seismic isolation operation,
A control program for driving the actuator 14 to return the upper base 4 to the origin position when the output of each of the sensors 15 to 17 becomes zero is stored.

[0025] Here, consider the operation when the lower base 5 is displaced in the X ₁ direction, the upper base 4 attempts stationary by static inertia, lower pulley 9c, 9d are top pulley 8 g, 8
h, the wire 12 is displaced in the direction in which the wire 12 is extended. Therefore, the rod 14a of the actuator 14 connected to the wire 12 is pulled in the direction B. At this time, since the actuator 14 is not driven, the wire 12 is pulled with almost no resistance. Therefore, the upper base 4 and the lower base 5 can be relatively displaced smoothly without receiving resistance other than friction of the spherical bearings 6a to 6d.

Further, the lower base 5 when displaced in the X ₂ direction, the lower pulley 9a is opposite to the reverse, 9b presses the wire 12 in a direction to extend the wire 12. Also in this case, since the actuator 14 is not driven as in the above case, the upper base 4 and the lower base 5 can be relatively displaced smoothly without receiving any resistance other than friction of the spherical bearings 6a to 6d. .

Further, the wire 12 when the when the lower base 5 is displaced in the Y ₁ direction wire 12 is pressed in the direction of the lower pulleys 9a, 9d can extend the wire 12, the lower base 5 is displaced in the Y ₂ direction It is pressed by the lower pulleys 9b and 9c. Also in this case, since the actuator 14 is not driven, as in the above case, the upper base 4 and the lower base 5 are relatively displaced without receiving any resistance other than friction of the spherical bearings 6a to 6d.

Here, control processing executed by the control device 18 will be described. FIG. 3 is a flowchart for explaining the processing executed by the control device 18. Control device 1
8 reads the signals output from the sensors 15 to 17 in step S1 (hereinafter, "step" is omitted), and checks in step S2 whether the lower base 5 is vibrating. In S2, when the lower base 5 is not vibrating, the process returns to S1, and when the lower base 5 is vibrating, the process proceeds to S3.

In S3, it is checked whether the displacement or acceleration of the upper base 4 is larger than a predetermined value. In step S3, when the displacement of the upper base 4 with respect to the lower base 5 or the acceleration occurring on the upper base 4 itself is larger than a predetermined value X, the upper base 4 is allowed with respect to the lower base 5. It is determined that there is a possibility of relative displacement to the stroke limit position, which is the maximum displacement, or possible displacement to the stroke limit position, and the process proceeds to S4, where the magnitude of the sensor signal output from the acceleration sensor 16 or the displacement sensor 17 is determined. A corresponding voltage is applied to the electromagnetic coil 14b of the actuator 14 to attract the magnet 14c in the direction A.

As a result, a resistance corresponding to the magnitude of the voltage value is applied to the wire 12, the tension of the wire 12 increases, and the acceleration of the upper base 4 is reduced. Therefore, the upper base 4 is prevented from exceeding the stroke limit, and the spherical bearing 6 slidably supports the upper base 4.
a to 6d are prevented from coming off the upper base 4. Therefore, it is possible to prevent the amplitude of the relative displacement of the upper base 4 from becoming too large and the seismic isolated object 2 from falling down.

In the next step S5, it is checked whether the displacement or acceleration of the upper base 4 has become zero. In S5, when the displacement or acceleration of the upper base 4 is not zero,
Since the upper base 4 is vibrating, the process returns to S3, and S3
To S5. If the displacement or acceleration of the upper base 4 is zero in S5, the process proceeds to S6, in which the application of the voltage to the electromagnetic coil 14b of the actuator 14 is stopped, and the control of the actuator 14 is stopped.

In step S3, if the displacement or acceleration of the upper base 4 is smaller than the predetermined value X, the process in step S6 is executed to stop the control of the actuator 14. In S3, if the displacement or acceleration of the upper base 4 is smaller than a predetermined value X before the drive of the actuator 14 is controlled,
The process proceeds to S6 without driving the actuator 14 at all.

As described above, when the displacement or acceleration of the upper base 4 is small, the actuator 14 is not driven.
The upper base 4 and the lower base 5 are provided with spherical bearings 6a to 6
d can be relatively displaced without receiving any resistance other than friction. Therefore, unlike the conventional case having a coil spring or a gas spring, a minute vibration is not propagated to the upper base 4 via the coil spring or the gas spring, and even if the minute vibration is propagated to the lower base 5, Can be prevented from transmitting to the seismic isolated object 2 due to relative displacement.

In S7, it is checked whether the lower base 5 is vibrating. In S7, the lower base 5
When is oscillating, the process returns to S3, and the processes of S3 to S7 are repeated. However, in S7, when the lower base 5 is not vibrating, the process proceeds to S8 and the actuator 1
4 is driven to return the upper base 4 to the origin position with respect to the lower base 5. That is, although the wire 12 is in a slack state due to the relative displacement between the upper base 4 and the lower base 5, when a voltage is applied to the electromagnetic coil 14b of the actuator 14, the magnet 14c is attracted in the direction A and the tension of the wire 12 is increased. And the upper base 4 can be returned to the origin position.

Then, when the upper base 4 returns to the origin position with respect to the lower base 5, the drive control of the actuator 14 is stopped, and the current processing ends. In the present embodiment, when the displacement of the upper base 4 with respect to the lower base 5 or the acceleration generated on the upper base 4 itself is larger than a predetermined value, the displacement of the upper base 4 depends on the sensor output of the displacement sensor 17 or the acceleration sensor 16. However, regardless of the predetermined value, the displacement sensor 17 or the acceleration sensor 1
A resistance force according to the sensor output of No. 6 may always be generated.

FIG. 4 is a front view of a second embodiment of the present invention, and FIG.
FIG. 5 is a plan view of a second embodiment of the present invention. FIG. 5 shows a state in which the upper base 4 is removed so that the internal configuration of the seismic isolation device can be understood. In the seismic isolation device 21, a rotary drive type motor 22 is provided instead of the linear drive type actuator 14. The drive shaft 22a of this motor 22
, A pulley 23 is attached.

The other end 12b of the tire 12 is locked to the outer periphery of the pulley 23, and the tire 12 is wound around the pulley 23 by driving the drive shaft 22a of the motor 22 to rotate. Then, the control device 18 operates as shown in FIG.
The control processing shown in FIG. In the above embodiment, the actuator is configured to return the upper base 4 to the home position by a linear drive motor or a rotary drive motor. However, other actuators such as a pneumatic cylinder may be used.

In the above embodiment, the wire 14 is stretched between the upper base 4 and the lower base 5 and the actuator 14 pulls the wire 12 back.
Is returned to the origin position. However, the present invention is not limited to this, and a configuration may be adopted in which the actuator is driven so that the actuator directly returns the upper base 4 to the origin position.

[0039]

As described above, according to the first aspect of the present invention,
After the seismic isolation operation is completed, the upper base can be returned to a predetermined position on the lower base by driving the actuator.Therefore, there is no need to provide a coil spring or gas spring as in the conventional case. Seismic isolation operation is possible even with small vibrations that cannot be seismically isolated because the spring force of the spring acts as resistance. Therefore, even when a seismically isolated object such as a precision instrument that is easily affected by minute vibrations is placed, the seismic isolation operation can be performed well and the minute vibration can be prevented from propagating to the seismically isolated object.

According to the second aspect of the present invention, during the seismic isolation operation, the actuator drives the upper base to displace the upper base with the lower base or to generate a resistance force corresponding to the acceleration of the upper base between the upper base and the lower base. In order to provide, the relative displacement between the upper base and the lower base is suppressed, and the displacement of the upper base is suppressed so that the amplitude between the upper base and the lower base does not exceed a stroke limit which is an allowable maximum displacement. be able to. Therefore, it is possible to prevent the amplitude of the movable member from exceeding the stroke limit and preventing further seismic isolation operation, and prevent the relative displacement between the upper base and the lower base from becoming too large and the seismic isolated object from collapsing. it can.

[Brief description of the drawings]

FIG. 1 is a front view of a first embodiment of a seismic isolation device according to the present invention.

FIG. 2 is a plan view of the first embodiment.

FIG. 3 is a flowchart illustrating a process executed by a control device.

FIG. 4 is a front view of a second embodiment of the seismic isolation device according to the present invention.

FIG. 5 is a plan view of a second embodiment.

[Explanation of symbols]

 1, 21 Seismic isolation device 2 Seismic isolated object 4 Upper base 5 Lower base 6a to 6d Spherical bearing 8a to 8h Upper pulley 9a to 9d Lower pulley 13 Wire 14 Actuator 15, 16 Acceleration sensor 17 Displacement sensor 18 Control device 22 Motor 23 Pulley

Claims (2)

[Claims] 1. A seismic isolation device comprising an upper base on which a seismic isolated object is mounted and a lower base movably supporting the upper base, wherein after the seismic isolation operation is completed, the upper base is connected to the lower base. An actuator for returning to a predetermined position is provided. 2. The seismic isolation device according to claim 1, wherein during the seismic isolation operation, a displacement force of the upper base with respect to the lower base or a resistance force according to an acceleration of the upper base is applied to the upper base and the lower base. A seismic isolation device, wherein the actuator is driven so as to be provided between the base and a base.