JP2009074652A - Seismic isolator and semiconductor manufacturing facility - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve a seismic isolating function by reducing a natural frequency of a structure. <P>SOLUTION: In this seismic isolator 10, a floor 1 is connected with a structure 8 by a pipe 5 with high rigidity, and vibrations of the structure 8 are restrained. This seismic isolator comprises a linear movement actuator 11 interposed between the floor 1 and the structure 8 and capable of driving the structure 8 to be relatively displaced from the floor 1, a relative displacement sensor 17 (rotary encoder) capable of detecting relative displacement of the structure 8 relative to the floor 1, and a controller 12 controlling the linear movement actuator 11 based on outputs of the relative displacement sensor 17. The controller 12 positively feedbacks the outputs of the relative displacement sensor 17 to control signals inputted to the linear movement actuator 11. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a seismic isolation device and semiconductor manufacturing equipment that suppress the transmission of vibration due to an earthquake to a structure such as a semiconductor manufacturing device or a building.

  There are a passive seismic isolation method and an active seismic isolation method as a seismic isolation device that suppresses transmission of vibration caused by an earthquake to a structure. The passive seismic isolation device has vibration absorbing means such as laminated rubber interposed between a floor surface (ground) and a structure (see, for example, Patent Document 1). By this vibration absorbing means, the natural frequency of the structure is set to be lower than the main frequency component of the seismic wave, and vibration transmission from the floor surface to the structure is suppressed (see FIG. 7A).

On the other hand, the active seismic isolation device has an actuator interposed between the floor surface and the structure, and cancels the vibration of the structure based on the output of an acceleration sensor or the like installed on the floor surface or the structure. The actuator is controlled (see, for example, Patent Document 2). In the event of an earthquake, horizontal relative displacement occurs between the floor and the structure, so a clearance is provided between the structure and the floor wall so that the structure does not collide with the floor wall. However, in order to reduce the dead space, it is desired to reduce the clearance as much as possible. Therefore, the active seismic isolation device is generally designed to reduce the absolute acceleration of the structure and suppress the relative displacement between the floor and the structure to suppress the shaking of the structure. It has been targeted.
Japanese Patent Publication No. 7-54132 Japanese Patent Laid-Open No. 10-299237

  By the way, in the passive seismic isolation device, the vibration absorbing means is required to have sufficient flexibility in order to make the natural frequency of the structure lower than the main frequency component of the seismic wave. However, when applied to a structure such as a semiconductor manufacturing apparatus, if a rigid body, which is an accessory such as a pipe, is connected between the floor and the structure, the rigid body is flexible to the vibration absorbing means. It is conceivable that the natural frequency on the structure side increases and the seismic isolation function decreases (see FIGS. 7B and 8).

  The active seismic isolation device described above is intended to reduce the absolute acceleration of the structure and moderately suppress the relative displacement between the floor and the structure. In order to maintain the seismic isolation function, there is nothing that aims to reduce the natural frequency on the structure side.

  Therefore, an object of the present invention is to improve the seismic isolation function by reducing the natural frequency on the structure side.

  The present invention has been made in view of the circumstances as described above, and the seismic isolation device according to the present invention is a seismic isolation device in which a floor surface and a structure are connected by a rigid body and the vibration of the structure is suppressed. An actuator that is interposed between the floor surface and the structure and is capable of being driven to displace the structure relative to the floor surface; and a relative displacement amount of the structure relative to the floor surface. And a controller that controls the actuator based on the output of the relative displacement sensor, and the controller detects the relative displacement when the floor surface is relatively displaced with respect to the structure. The output of the relative displacement sensor is fed back to a control signal input to the actuator.

  According to the above configuration, when the floor surface is displaced relative to the structure, the actuator is controlled to amplify the relative displacement. Then, even if a force that reduces the relative displacement between the floor surface and the structure is exerted by the rigid body, the force can be canceled by the actuator. Therefore, the seismic isolation function can be improved.

  The controller may control the actuator so as to reduce the natural frequency of the structure.

  According to the said structure, since the natural frequency by the side of a structure is reduced, a seismic isolation function can be improved.

  The controller may control the actuator such that an apparent spring constant of the operation by the actuator cancels a spring constant of the rigid body.

  According to the above configuration, for example, when the spring constant of the rigid body is kp and the spring constant compensated by the actuator is kc, the controller is set so that kc≈−kp, so that the rigid body exists. Therefore, the same function as that of a normal passive seismic isolation device in which the structure is supported only by the vibration absorbing means can be maintained, and the seismic isolation function can be more effectively exhibited.

  The actuator is a linear motion actuator including a motor having a rotational position detection means and a linear motion mechanism that converts rotational motion by the motor into linear motion, and the rotational position detection means also serves as the relative displacement sensor. May be.

  According to the above configuration, since the rotational position detecting means attached to the motor is also used as a relative displacement sensor, it is not necessary to provide a stroke sensor or the like as a relative displacement sensor as a separate component, and the number of components can be reduced. .

  You may further provide the damper interposed between the said floor surface and the said structure.

  According to the above configuration, since the damper attenuates the vibration of the floor surface due to the seismic wave, the actuator needs only a small output, and the cost can be reduced.

  A semiconductor manufacturing facility according to the present invention includes the above-described seismic isolation device and a semiconductor manufacturing device constituting the structure.

  According to the above configuration, since the vibration transmission from the floor surface to the semiconductor manufacturing apparatus is sufficiently suppressed by the seismic isolation device, it is possible to realize a semiconductor manufacturing facility with high earthquake resistance.

  As is clear from the above description, according to the present invention, the flexibility of the vibration absorbing means is sufficiently exhibited, the apparent natural frequency on the structure side is reduced, and the seismic isolation function can be improved. .

  Embodiments according to the present invention will be described below with reference to the drawings.

  FIG. 1 is a schematic view showing a seismic isolation device 10 according to an embodiment of the present invention. As shown in FIG. 1, in a semiconductor manufacturing factory, a fixed floor 2 on which an operator walks is provided on a floor surface 1 integrated with the ground. In the semiconductor manufacturing facility 100, in a place where the fixed floor 2 does not exist on the floor surface 1, vibration absorbing means 9 made of laminated rubber is installed on the floor surface 1, and the structure 8 is supported by the vibration absorbing means 9. Yes. That is, the vibration absorbing means 9 absorbs horizontal vibrations of the floor surface 1 caused by seismic waves and suppresses the acceleration of the structure 8.

  The structure 8 includes a base isolation floor 3 supported by the vibration absorbing means 9 and a semiconductor manufacturing apparatus 4 installed on the base isolation floor 3. The seismic isolation floor 3 is disposed at substantially the same height as the fixed floor 2 with a predetermined clearance with respect to the fixed floor 2. In addition, the semiconductor manufacturing apparatus 4 is connected to an end of a metal pipe 5 that is a rigid body having higher rigidity than the vibration absorbing means 9, and a required portion of the pipe 5 is fixed to the floor surface 1. Yes. Therefore, not only the vibration absorbing means 9 but also the rigid pipe 5 is connected between the floor surface 1 and the structure 8.

  The seismic isolation device 10 controls the linear motion actuator 11 interposed between the floor surface 1 and the base isolation floor 3 and the linear motion actuator 11 based on the relative displacement between the floor surface 1 and the base isolation floor 3. And a controller 12 for performing the above operation. A fixed bracket 6 is fixed on the floor surface 1, and a movable bracket 7 is fixed to the lower surface of the seismic isolation floor 3, and a horizontal straight movement is generated between the brackets 6, 7. A linear actuator 11 is interposed. As described above, the semiconductor manufacturing facility 100 is configured by the base isolation device 10, the base isolation floor 3, and the semiconductor manufacturing apparatus 4.

  FIG. 2 is a plan view mainly showing the linear actuator 11 of the seismic isolation device 10 shown in FIG. As shown in FIG. 2, the linear motion actuator 11 includes an AC servo motor 14 and a linear motion mechanism 15 that converts the rotational motion of the AC servo motor 14 into linear motion. The AC servo motor 14 includes a motor main body 16 having a drive shaft (not shown), and a rotary encoder 17 (rotational position detecting means) capable of detecting the rotation phase of the drive shaft (not shown) of the motor main body 16. Have. The operation of the AC servo motor requires a rotary encoder, and a commercially available AC servo motor is usually provided with a rotary encoder.

  A ball screw 18 is connected to a drive shaft (not shown) of the motor body 16, and the movable bracket 7 is screwed to the ball screw 18. The movable bracket 7 is guided in one direction by a linear guide 19 arranged in parallel with the axial direction of the ball screw 18. That is, when the ball screw 18 is rotated by driving the motor body 16, the movable side bracket 7 moves along the linear guide 19, and the horizontal distance between the floor surface 1 and the seismic isolation floor 3 changes. It will be.

  A controller 12 is connected to the AC servo motor 14. The controller 12 receives the output of the rotary encoder 17, calculates a relative displacement amount of the floor surface 1 with respect to the seismic isolation floor 3 based on the output, and transmits a control signal to the motor body 16 based on the calculation result. The AC servo motor 14 is controlled. That is, the rotary encoder 17 also serves as a relative displacement sensor that can detect the relative displacement amount of the floor surface 1 with respect to the seismic isolation floor 3.

  FIG. 3 is a diagram for explaining the positive feedback control of the controller 12 of the seismic isolation device 10 shown in FIG. As shown in FIG. 3, the controller 12 determines the output value of the rotary encoder 17 (relative displacement sensor) of the linear actuator 11, that is, the relative displacement amount between the floor surface 1 and the seismic isolation floor 3. In this configuration, the control signal to be fed back to the control signal is positively fed back. Note that kc in FIG. 3 is a compensation element. In this way, when the floor 1 is displaced relative to the base-isolated floor 3 by the vibration absorbing means 9 absorbing the roll caused by the seismic wave, the linear actuator 11 is controlled to amplify the relative displacement. Become. That is, even if a resistance that reduces the relative displacement between the floor surface 1 and the seismic isolation floor 3 is generated by the pipe 5, the force by the linear actuator 11 acts so as to cancel the resistance.

Specifically, if the spring constant of the vibration absorbing means 9 is kb, the spring constant of the pipe 5 is kp, the spring constant compensated by the linear motion actuator 11 is kc, and the mass of the structure 8 is m, the structure 8 The natural frequency f _n can be expressed as follows from the equation of motion.

f _n = √ {(kb + kp + kc) / m} / 2π (1)
At this time, since the spring constant kc is controlled to be a negative value with respect to the spring constant kp by positive feedback, the apparent natural frequency f _{n of} the structure 8 is reduced by kc, and vibration absorbing means 9 flexibility is fully exhibited, and the seismic isolation function can be improved. In particular, if kc≈−kp, the same function as a normal passive seismic isolation device in which the structure 8 is supported only by the vibration absorbing means 9 without the pipe 5 can be maintained, and the seismic isolation function is effective. It is possible to demonstrate it. That is, as can be seen from the graph of FIG. 4, the frequency response in the seismic isolation device 10 of the present invention can be in the same state as the frequency response of the passive seismic isolation device without the pipe 5 shown in FIG. . Therefore, as shown in FIG. 5, it is possible to suppress the roll of the floor surface 1 due to the seismic wave from being transmitted to the seismic isolation floor 3.

  Furthermore, in this embodiment, since the rotary encoder 17 attached to the AC servomotor 14 is also used as a relative displacement sensor, it is not necessary to provide a stroke sensor or the like as a relative displacement sensor as a separate part, and the number of parts can be reduced. It becomes possible to reduce. Further, since the apparent spring constant of the operation by the linear actuator 11 can be continuously adjusted by the controller 12, it is possible to reduce the design man-hour compared with the adjustment work of the spring constant using the spring member. It becomes.

  Next, FIG. 6 is a schematic diagram showing a seismic isolation device 20 according to a modification of the present invention. In addition, about the part which is common in embodiment shown in FIG. 1, the same code | symbol is attached | subjected and description is abbreviate | omitted. As shown in FIG. 6, in the seismic isolation device 20 of the modified example, a damper 21 is interposed between the floor surface 1 and the seismic isolation floor 3. A fixed bracket 22 is fixed on the floor surface 1, and a movable bracket 23 is fixed to the lower surface of the seismic isolation floor 3, and a damper that attenuates horizontal vibration between the brackets 22, 23. 21 is connected. According to this configuration, the damper 21 attenuates the horizontal vibration of the floor surface 1 due to the seismic wave, so that the motor used for the linear motion actuator 11 is sufficient with a small output, and the cost can be reduced. . Other configurations are the same as those of the embodiment shown in FIG.

  In the embodiment described above, laminated rubber is exemplified as the vibration absorbing means. However, the present invention is not limited to this. For example, a ball attached to the seismic isolation floor is rotatably mounted on a dish member attached to the floor surface. A placed ball support mechanism or the like may be used. In the above-described embodiment, the rotary encoder attached to the motor is exemplified as the relative displacement sensor. However, the present invention is not limited to this. For example, a stroke sensor may be used as a separate component from the motor. In the above-described embodiment, the structure includes two seismic isolation floors and a semiconductor manufacturing apparatus. However, the structure is not limited thereto, and may be a single building such as an apartment or a building. Furthermore, in the above-described embodiment, a rotary encoder is used as the rotational position detection means, but a rotational angle sensor such as a resolver may be used.

  As described above, the seismic isolation device and the semiconductor manufacturing facility according to the present invention have an excellent effect of improving the seismic isolation function, such as a semiconductor manufacturing device or a building that can demonstrate the significance of this effect. It is useful when applied to seismic isolation devices for structures.

It is the schematic which shows the seismic isolation apparatus which concerns on embodiment of this invention. FIG. 2 is a plan view mainly showing a linear actuator of the seismic isolation device shown in FIG. 1. It is drawing explaining the positive feedback control of the controller of the seismic isolation apparatus shown in FIG. It is a graph which shows the frequency response in the seismic isolation apparatus shown in FIG. It is the graph which compared the absolute acceleration of the floor surface and structure in the seismic isolation apparatus shown in FIG. It is the schematic which shows the seismic isolation apparatus which concerns on the modification of this invention. (A) is a graph which shows the frequency response in the conventional passive seismic isolation (without a rigid body), (b) is a graph which shows the frequency response in the conventional passive seismic isolation (with a rigid body). It is the graph which compared the absolute acceleration of the floor surface and a structure in the conventional passive seismic isolation (with a rigid body).

Explanation of symbols

1 Floor 3 Seismic Isolation Floor 4 Semiconductor Manufacturing Equipment 5 Piping (Rigid Body)
8 Structure 9 Vibration Absorbing Means 10, 20 Seismic Isolation Device 11 Linear Actuator 12 Controller 14 AC Servo Motor 15 Linear Motion Mechanism 16 Motor Body 17 Rotary Encoder (Rotation Position Detection Means and Relative Displacement Sensor)
21 Damper 100 Semiconductor manufacturing equipment

Claims (6)

A seismic isolation device in which a floor surface and a structure are connected by a rigid body to suppress vibration of the structure,
An actuator that is interposed between the floor surface and the structure and that can be driven to displace the structure relative to the floor surface;
A relative displacement sensor capable of detecting a relative displacement amount of the structure relative to the floor surface;
A controller for controlling the actuator based on the output of the relative displacement sensor,
The controller feeds back an output of the relative displacement sensor to a control signal input to the actuator so as to amplify the relative displacement when the floor surface is displaced relative to the structure. Seismic isolation device.   The seismic isolation device according to claim 1, wherein the controller controls the actuator so as to reduce a natural frequency of the structure.   The seismic isolation device according to claim 1, wherein the controller controls the actuator so that an apparent spring constant of the operation by the actuator cancels a spring constant of the rigid body. The actuator is a linear motion actuator comprising a motor having a rotational position detection means and a linear motion mechanism that converts rotational motion by the motor into linear motion,
The seismic isolation device according to any one of claims 1 to 3, wherein the rotational position detecting means also serves as the relative displacement sensor.   The seismic isolation device according to any one of claims 1 to 4, further comprising a damper interposed between the floor surface and the structure.   6. A semiconductor manufacturing facility comprising the seismic isolation device according to claim 1 and a semiconductor manufacturing apparatus constituting the structure.

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