JP2005036838A - Compound actuator - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a compound actuator with a simple structure which can be easily controlled and in which turning force does not occur. <P>SOLUTION: The compound actuator is composed of a voice coil motor 10 and a gas actuator. The voice coil motor 10 is composed of a cup-shaped external yoke 12, a columnar internal yoke 13, a permanent magnet 11 provided on the outer periphery of the internal yoke 13, and a coil 14 arranged between the permanent magnet 11 and the external yoke 12. The gas actuator 20 is composed of a tray-like substrate 21 and a diaphragm 24 provided air-tightly between the inner periphery of the substrate 21 and the internal yoke 13. The coil 14 is wound around a bobbin 15 integrally provided on the upper face of the substrate 21. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a composite actuator used for vibration isolation of an ultraprecision processing apparatus, for example, a semiconductor manufacturing apparatus.
[0002]
[Prior art]
As this type of actuator, a structure combining an air spring and a linear motor (voice coil motor) is well known, and many proposals have been made. For example, Patent Document 1 discloses a vibration isolation device in which an air spring and a linear motor are connected in series. In this vibration isolator, since the driving direction of the air spring and the linear motor are orthogonal to each other, it is difficult to control, and the linear motor coil support frame is cantilevered.
[0003]
Further, Patent Document 2 discloses a vibration isolator in which one of an air spring and a voice coil motor is provided with the other. However, since this vibration isolator has a structure that is easily heated from inside or outside of the air spring due to heat generated by the voice coil motor, there is a problem that the pressure of the air spring largely fluctuates.
[0004]
In Patent Document 3, a gas actuator that supports an action member by an elastic member in a casing is configured, and a frame having permanent magnets arranged opposite to each other above and below a coil portion fixed to the casing is fixed to the action member. A hybrid actuator comprising a linear actuator is disclosed. In this hybrid actuator, since the gas actuator has thrust in the Z-axis direction and the linear actuator has thrust in the X-axis direction, there is a problem that the control becomes complicated and the structure becomes complicated.
[0005]
[Patent Document 1]
JP-A-8-285176 (paragraphs 0013, 0019, FIG. 8, FIG. 9)
[Patent Document 2]
JP-A-5-340444 (paragraphs 0026, 0027, 0028, 0029, 0031, 0032, FIGS. 1 and 2)
[Patent Document 3]
Japanese Patent Laying-Open No. 2002-122180 (paragraphs 0006, 0007, 0008, FIG. 1)
[0006]
[Problems of the Invention]
Accordingly, an object of the present invention is to provide a composite actuator that is easy to control with a simple structure and does not generate a rotational force.
[0007]
[Means for solving problems]
In order to solve the above-described problems, in the present invention, an inner yoke is provided on the inner surface of the cup-shaped outer yoke, a permanent magnet is fixed to an appropriate portion of the inner yoke, and the space between the skirt portion of the outer yoke and the inner yoke is fixed. And a voice coil motor having a coil opposed to the permanent magnet disposed thereon, and a diaphragm is hermetically attached between the inner peripheral portion of the tray-like substrate and the inner yoke, and is defined by the inner surface of the inner yoke and the diaphragm and the substrate. A composite actuator is constituted by a gas actuator having a pressure chamber, and the substrate and the bobbin of the coil are integrated.
[0008]
The diaphragm may be airtightly provided between the skirt portion of the outer yoke and the bobbin to which the coil is attached. In this case, the pressure chamber of the gas actuator is formed by the inner surface of the outer yoke, the inner yoke and the substrate.
[0009]
In addition, a coolant passage that circulates around the substrate may be provided in the vicinity of the coil.
[0010]
Embodiment
Embodiments of the present invention will be described below with reference to the accompanying drawings. As shown in FIG. 1, the composite actuator includes a voice coil motor 10 and a gas actuator 20. The voice coil motor 10 includes a tray-shaped or cup-shaped outer yoke 12, a columnar inner yoke 13 fixed to the inner surface of the outer yoke 12, a ring-shaped permanent magnet 11 fixed to the outer periphery of the inner yoke 13, The outer yoke 12 comprises a coil 14 provided facing the outer periphery of the skirt portion 12a and the permanent magnet 11 with a predetermined interval.
[0011]
The gas actuator 20 includes a tray-shaped or cup-shaped substrate 21, a flange portion 23 projecting inward from a side wall 22 of the substrate 21, and a diaphragm 24 provided between the inner yoke 13. The inner space surrounded by the diaphragm 24 and the lower surface of the inner yoke 13 forms an airtight pressure chamber 25. The bobbin 15 that holds the coil 14 is integrated with the flange portion 23 of the substrate 21.
[0012]
As shown in FIGS. 1 and 2, the protrusion 24 b provided on the outer flange 24 a of the diaphragm 24 is sandwiched between the inner surface of the flange portion 23 of the substrate 21 and the support ring 26 a, and the inner flange 24 c is connected to the inner yoke 13. The yokes 12 and 13 and the magnet 11 are supported so as to be movable in the Z-axis direction with respect to the substrate 21 by a movable film portion 24d having a substantially semicircular cross section. The diaphragm 24 may have a ring shape as shown in the figure, but may be a single piece having no space in the center.
[0013]
A cooling liquid circulation passage 27 is provided in the flange portion 23 of the substrate 21 in the vicinity of the coil 14. The passage 27 is provided with a coolant supply hole 27a. The pressure chamber 25 communicates with a supply hole 25a for pressurized gas, for example, compressed air.
[0014]
FIG. 3 shows another embodiment of the present invention. As shown in the figure, the bobbin 15 provided integrally with the substrate 21 of the gas actuator 20 is extended and the inner flange 24c of the diaphragm 24 is sandwiched by the support ring 26b at the tip, and the outer flange 24a is the skirt portion of the outer yoke 12. 12a is sandwiched in the middle. The pressure chamber 25 is a space defined by the inner surface of the substrate 21 and the bobbin 15, the lower surface and outer peripheral surface of the inner yoke 13, and the outer peripheral surface of the magnet 11, and the lower surface of the outer yoke 12 and the upper inner surface of the skirt portion 12a. Formed.
[0015]
FIG. 4 shows still another embodiment of the composite actuator. As illustrated, a disk-shaped permanent magnet 11 is fixed to the inner surface of the cup-shaped outer yoke 12, and an inner yoke 13 is fixed to the lower surface of the permanent magnet 11. In this embodiment, a disk-shaped permanent magnet 11 is disposed between the outer yoke 12 and the inner yoke 13 in place of the permanent magnet 11 of FIG. Similarly, instead of the embodiment of FIG. 3, a disk-shaped permanent magnet 11 may be disposed between the outer yoke 12 and the inner yoke 13, or the disk-shaped permanent magnet 11 is disposed on the lower surface of the inner yoke 13. It may be fixed.
[0016]
Although not shown, a sensor for detecting the displacement and acceleration of the outer yoke 12 or the inner yoke 13 can be attached at appropriate positions. The sensor signal is input to an appropriate control device to control the composite actuator of the present invention. Now, when compressed gas is sent into the pressure chamber 25 from the supply hole 25a and the gas pressure is adjusted as appropriate, thrust in the Z-axis direction acts on the inner yoke 13. On the other hand, when a current is passed through the coil 14, a thrust in the Z-axis direction acts on the inner yoke 13 according to Fleming's law. By controlling these thrusts in response to the signals from the sensors, it is possible to perform vibration isolation of a vibration generating source such as a semiconductor manufacturing apparatus.
[0017]
【The invention's effect】
According to the present invention, as described above, since the gas actuator is arranged in series via the diaphragm on the inner or outer yoke of the vertical voice coil motor, a compact and small composite actuator can be obtained. Since no extra flange or the like is required, the rigidity is high, and control is easy because the thrust axis of the voice coil motor and the gas actuator coincide.
[0018]
Further, since the coil portion of the voice coil motor is arranged outside the gas actuator, the voice coil motor is not affected by the gas pressure, and the pressure fluctuation of the gas actuator is caused by the heating and expansion of the gas due to the heat generation of the coil portion. Therefore, a composite actuator with stable performance can be obtained. In addition, the performance can be further stabilized by providing a cooling mechanism for the coil section.
[0019]
In addition, since a diaphragm having a structure sandwiched between the inner yoke or the outer yoke and the substrate of the gas actuator facing them is used, the effective pressure-receiving area for vertical displacement is equal to the pressure in comparison with the bellows, etc. Therefore, the horizontal position fluctuation due to the pressure is small, the return after the displacement in the horizontal direction is quick, and the horizontal position stability and the position reproducibility are good.
[Brief description of the drawings]
FIG. 1 is a longitudinal sectional view showing an example of a composite actuator of the present invention. FIG. 2 is a plan view of a diaphragm used in a gas actuator. FIG. 3 is a longitudinal sectional view showing another example of the composite actuator. Vertical sectional view showing still another example [Explanation of symbols]
DESCRIPTION OF SYMBOLS 10 Voice coil motor 11 Permanent magnet 12 Outer yoke 12a Skirt part 13 Inner yoke 14 Coil 15 Bobbin 20 Gas actuator 21 Substrate 22 Side wall 23 Flange part 24 Diaphragm 24a Outer flange 24b Projection 24c Inner flange 24d Movable film 25 Pressure chamber 25a Gas supply Holes 26a and 26b Support ring 27 Coolant circulation passage 27a Coolant supply hole

Claims (3)

A voice coil motor in which an inner yoke is provided on the inner surface of the cup-shaped outer yoke, a permanent magnet is fixed to an appropriate portion of the inner yoke, and a coil facing the permanent magnet is disposed between the skirt portion of the outer yoke and the inner yoke. And a gas actuator in which a diaphragm is hermetically attached between the inner peripheral portion of the tray-like substrate and the inner yoke, and a pressure chamber defined by the inner yoke inner surface, the diaphragm and the substrate is formed. Combined actuator with bobbin. A voice coil motor in which an inner yoke is provided on the inner surface of the cup-shaped outer yoke, a permanent magnet is fixed to an appropriate portion of the inner yoke, and a coil facing the permanent magnet is disposed between the skirt portion of the outer yoke and the inner yoke. And a pressure chamber defined by the inner surface of the outer yoke, the inner yoke, and the substrate, wherein a diaphragm is hermetically attached between the bobbin of the coil and the skirt portion of the outer yoke integrally extending upward from the outer periphery of the tray-shaped substrate. A composite actuator consisting of a gas actuator formed with 3. The composite actuator according to claim 1, wherein a passage of a coolant that circulates around the substrate is provided in the vicinity of the coil.

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