JP2004254453A - Side force measuring device of linear motor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a side force measuring device that can measure the side force of a linear motor with high accuracy. <P>SOLUTION: A movable stage 5 arranged with the linear motor 2 of which the moving member 22 can move in the vertical direction is arranged on a base 3, the movable stage 5 is movably supported to a direction orthogonal to the vertical direction by an air bearing 7, and a force in the y-direction of the movable stage 5 is detected by a load cell 9. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a side force measuring device capable of measuring a side force of a linear motor.
[0002]
[Prior art]
As a conventional technique, a pair of load cells are arranged at both ends of a linear coil of a linear motor, and a drive motor is used to measure the difference between the outputs of both load cells while moving a linear magnet of the linear motor along the linear coil by a servo motor. There is a device (see the following publication).
[0003]
The linear magnet is held on a movable table.
[0004]
The position of the linear magnet relative to the linear coil is detected by a linear encoder.
[0005]
The driving force of the linear motor is calculated based on the detected position of the linear magnet and the difference between the outputs of the two load cells.
[0006]
[Patent Document 1]
JP-A-7-98256
[Problems to be solved by the invention]
In the conventional technology, the difference between the outputs of both load cells is obtained to cancel the measurement error, and the thrust acting on the linear magnet can be measured. However, the force (side force) in the direction orthogonal to the thrust direction is measured. Can not.
[0008]
Even if a load cell is arranged around the linear magnet to measure the side force, it is difficult to measure with high accuracy because the sliding resistance of the movable table holding the linear magnet is large.
[0009]
The present invention has been made in view of such circumstances, and an object thereof is to provide a side force measuring device capable of measuring the side force of a linear motor with high accuracy.
[0010]
[Means for Solving the Problems]
In order to solve the above-mentioned problem, a side force measuring device for a linear motor according to the present invention comprises a base, a movable stage disposed on the base, and a linear motor on which a mover can move in a vertical direction. A stage supporting means for movably supporting the movable stage in a direction perpendicular to the vertical direction via a fluid, and a detecting means for detecting a force of the movable stage in a direction perpendicular to the vertical direction. Features.
[0011]
As described above, since the stage supporting means supports the movable stage movably in the direction perpendicular to the vertical direction via the fluid, the resistance when moving the movable stage in the direction perpendicular to the vertical direction is negligibly small. Become.
[0012]
According to a second aspect of the present invention, in the linear motor side force measuring device according to the first aspect, the detecting means is a load cell.
[0013]
Since the detection means is a load cell as described above, even if the force acting on the movable stage is small, the force can be detected.
[0014]
According to a third aspect of the present invention, there is provided a linear motor side force measuring apparatus according to the first or second aspect, wherein the stage supporting means is provided on a lower surface of the movable stage. It is characterized by having a nozzle and a compressed air supply device for supplying compressed air to the upper surface of the base through the plurality of air injection nozzles.
[0015]
As described above, the stage support means has a plurality of air injection nozzles provided on the lower surface of the movable stage, and a compressed air supply device for supplying compressed air to the upper surface of the base through the plurality of air injection nozzles. The resistance when moving the movable stage in a direction perpendicular to the direction is reduced.
[0016]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
[0017]
FIG. 1 is a perspective view of a side force measuring device for a linear motor according to an embodiment of the present invention, FIG. 2 is a front view of the side force measuring device for a linear motor shown in FIG. 1, and FIG. FIG. 4 is a side view of the side force measuring device, and FIG. 4 is a plan view of the side force measuring device of the linear motor shown in FIG.
[0018]
This linear motor side force measuring device is a device for measuring the side force of the linear motor 2, that is, the force in the direction orthogonal to the thrust of the linear motor. This side force measuring device can also measure the thrust of the linear motor 2.
[0019]
As shown in FIG. 1, the linear motor 2 includes a stator (not shown) and a mover 22. This linear motor 2 is used, for example, in a semiconductor manufacturing apparatus. The stator has a rectangular coil and a jacket covering the coil. The mover 22 is movable along the x direction (vertical direction). The mover 22 has a yoke 221 and a pair of magnets 222 (only one magnet is shown). The yoke 221 has a substantially rectangular tube shape. The pair of magnets 222 are attached to face the inner wall surface of the yoke 221. The pair of magnets 222 form a magnetic path together with the yoke 221. A part of the magnetic flux passing through the magnetic path is orthogonal to one side of the coil extending along the y direction.
[0020]
The side force measuring device includes a base 3, a movable stage 5, an air bearing 7, and first and second side force detecting load cells 9, 11.
[0021]
The base 3 is formed in a substantially hexagonal shape as shown in FIG. A first base-side fixing plate 31 is fixed to one end of the base 3 in the y direction by bolts 35. The thickness direction of the first base-side fixing plate 31 is parallel to the y direction (see FIG. 1). An elongated hole 31a extending in the x-direction is formed in an upper portion of the first base-side fixing plate 31. A second base-side fixing plate 32 is attached to one end of the base 3 in the z direction by bolts 35. The thickness direction of the second base-side fixing plate 32 is parallel to the z direction. An elongated hole 32a extending in the x-direction is formed in an upper portion of the second base-side fixed plate 32.
[0022]
A mover support arm 33 is attached to the other end of the base 3 in the z direction. The mover support arm 33 has an arm main body 331, a mounting plate 332, a horizontal plate 333, and a reinforcing plate 334. The arm body 331 is formed substantially in an L shape, and has a reinforcing rib 331a. The mounting plate 332 is mounted on the upper end of the arm body 331. The position of the mounting plate 332 in the x direction with respect to the arm body 331 can be adjusted. The horizontal plate 333 is fixed to the mounting plate 332. The reinforcing plate 334 is fixed to the mounting plate 332 and the horizontal plate 333, and the mounting plate 332 and the horizontal plate 333 are firmly connected.
[0023]
As shown in FIG. 2, legs 34 are attached to three places on the lower surface of the base 3. The leg 34 has a male thread (not shown), and this male thread is fitted into a female thread (not shown) formed on the base 3. Therefore, the length of the leg 34 can be adjusted.
[0024]
The movable stage 5 is arranged on the base 3. A first stage-side fixing plate 51 is attached to one end of the movable stage 5 in the y direction by bolts 55. The thickness direction of the first stage side fixed plate 51 is parallel to the y direction (see FIG. 1). A second stage-side fixing plate 52 is attached to one end of the movable stage 5 in the z direction by bolts 55. The thickness direction of the second stage side fixing plate 52 is parallel to the z direction. As shown in FIG. 3, a stator support block 53 is fixed to the other end of the movable stage 5 in the z direction. The stator support block 53 supports the stator. Two balance weights 54 are attached to the upper surface of the movable stage 5.
[0025]
The air bearing 7 has a bolt portion 7a. The bolt portion 7a is passed through an insertion hole (not shown) formed in the movable plate 5. A nut 72 is fitted into a portion of the bolt portion 7a protruding from the upper surface of the movable stage 5. Thus, the three air bearings 7 are attached to the lower surface of the movable stage 5. The air bearing 7 has a nozzle portion (not shown), and this nozzle portion jets compressed air supplied from a compressor (not shown) as a compressed air supply device toward the upper surface of the base 3. Stage support means for movably supporting the movable stage 5 in a direction orthogonal to the vertical direction is constituted by the air bearing 7 and the compressor.
[0026]
One end of the first side force detection load cell 9 is fixed to the first stage-side fixing plate 51 by a screw (not shown), and the other end of the first side force detection load cell 9 is connected to the first base by a screw 91. It is fixed to a fixing plate 31. Adjustment of the mounting position of the first side force detection load cell 9 in the x direction can be performed by tightening or loosening the screw 91 on the first base side fixed plate 31 side.
[0027]
One end of the second side force detection load cell 11 is fixed to the second stage side fixing plate 52 by a screw (not shown), and the other end of the second side force detection load cell 11 is connected to the second base side by a screw 111. It is fixed to a fixing plate 32. Adjustment of the mounting position of the second side force detection load cell 11 in the x direction can be performed by tightening or loosening the screw 111 on the second base side fixing plate 32 side.
[0028]
One end of the thrust detection load cell 13 is fixed to the horizontal plate 333 of the mover support arm 33 with a screw (not shown), and the other end of the thrust detection load cell 13 is fixed with a screw (not shown). 15 fixed.
[0029]
The mover holding member 15 has a horizontal plate 151 and a pair of vertical plates 152 connected to both ends of the horizontal plate 151.
[0030]
The yoke 221 of the mover 22 is positioned with respect to the mover holding member 15 by a pin 153, and is fixed to the mover holding member 15 by a screw 154 (see FIG. 3). The mover 22 is suspended from the mover support arm 33 via the mover holding member 15 and the thrust detection load cell 13.
[0031]
Next, a procedure for measuring the side force of the linear motor using the linear motor side force measuring device of this embodiment will be described.
[0032]
When measuring the side force in the y direction of the linear motor 2, the second side force detection load cell 11 is detached from the second base side fixed plate 32 and the second stage side fixed plate 52.
[0033]
Before the measurement, the lengths of the legs 34 and the bolts 7a are adjusted so that the upper surfaces of the base 3 and the movable stage 5 are horizontal.
[0034]
Next, when the movable stage 5 floats from the base 3 by the air bearing 7, the weight of the balance weight 54 is adjusted so that the upper surface of the movable stage 5 becomes horizontal.
[0035]
Also, the first side force is set so that the mounting position of the first side force detection load cell 9 in the x direction is the same as the position of the first side force detection load cell 9 in the x direction when the movable stage 5 is levitated. Adjustment of the mounting position of the detection load cell 9 in the x direction is performed by loosening or tightening the screw 91 on the first base side fixing plate 31 side.
[0036]
When the above preparation is completed, the side force of the linear motor 2 in the y direction is measured.
[0037]
First, compressed air is supplied to the air bearing 7 by the compressor. When the compressed air is supplied, the movable stage 5 floats and separates from the base 3.
[0038]
Next, a current is supplied to the coil of the linear motor 2. When an electric current is applied, a thrust is generated in the mover 22, and the mover 22 slightly moves upward. The thrust of the mover 22 is transmitted to the thrust detection load cell 13 via the mover holding member 15. The load cell 13 for thrust detection is distorted by the thrust of the mover 22, and outputs an electric signal corresponding to the distortion. The thrust is measured based on the electric signal.
[0039]
If one side of the above-mentioned coil is not oriented in the correct direction, a side force in the y-direction will be generated when a current flows through the coil. When the y-direction side force is generated, the mover 22 tries to move along the y-direction by the y-direction side force. However, the thrust detection load cell 13 connected to the mover 22 via the mover holding member 15 allows the mover 22 to move in the x direction, but does not allow the mover 22 to move in the y direction and the z direction. Block. Therefore, the mover 22 does not move in the y direction, and the reaction force of the side force in the y direction at this time is applied to the stator. Since the stator is connected to the movable stage 5 via the stator support block 53, the movable stage 5 moves along the y direction when a reaction force of the side force in the y direction is applied to the stator. At this time, since the movable stage 5 is floating, it moves very smoothly. Therefore, the reaction force of the side force in the y direction is transmitted to the first side force detection load cell 9 via the first stage-side fixing plate 51 without weakening. Due to the reaction force of the side force, the first side force detecting load cell 9 is distorted, and an electric signal corresponding to the distortion is output. The reaction force of the y-direction side force differs from the y-direction side force only in direction, and is the same strength as the y-direction side force. Therefore, the y-direction side force is detected based on the electric signal of the first side force detection load cell 9. The strength of the force can be measured.
[0040]
To measure the side force in the z-direction, the first side force detection load cell 9 is detached from the first stage-side fixed plate 51 and the first base-side fixed plate 31, and the second stage-side fixed plate 52 and the second The second side force detection load cell 11 is attached to the base side fixing plate 32.
[0041]
The side force in the y direction is mainly caused by a mounting error of the coil, and the side force in the z direction is mainly generated by a mounting error of the magnet.
[0042]
As described above, according to the linear motor side force measuring device of this embodiment, the movable stage 5 is floated by the three air bearings 7 and the sliding resistance is eliminated, so that the side force can be measured with high accuracy. it can.
[0043]
The side force measuring device for a linear motor according to this embodiment is for a linear motor used in a semiconductor manufacturing device or the like, but, of course, the present invention can be used as a side force measuring device for another type of linear motor. .
[0044]
In this embodiment, the stator is fixed to the movable stage 5 and the mover 22 is fixed to the base 3. However, the mover 22 is fixed to the movable stage 5, and the stator is fixed to the base 3. Is also good.
[0045]
In this embodiment, the stage supporting means composed of the air bearing 7 and the compressor is used. However, the stage supporting means is not limited to this. For example, the stage supporting means is attached to the base 3 and is directed toward the movable stage 5. A nozzle that injects compressed air to the nozzle and a compressor that supplies compressed air to the nozzle, or a nozzle that is attached to the movable stage 5 and injects liquid such as water toward the base 3, A pump for supplying a liquid to the nozzle may be used.
[0046]
【The invention's effect】
As described above, according to the linear force side force measuring device of the first aspect of the present invention, the side force can be measured with high accuracy.
[0047]
According to the linear force side force measuring device of the invention of claim 2 or 3, the side force can be measured with higher accuracy.
[Brief description of the drawings]
FIG. 1 is a perspective view of a side force measuring device for a linear motor according to an embodiment of the present invention.
FIG. 2 is a front view of the side force measuring device for a linear motor shown in FIG. 1;
FIG. 3 is a side view of the linear force measuring device for a linear motor shown in FIG. 1;
FIG. 4 is a plan view of the linear force side force measuring device shown in FIG. 1;
[Explanation of symbols]
2 linear motor 22 mover 3 base 31 first fixed side fixed plate 32 second fixed side fixed plate 33 mover support arm 34 leg 5 movable stage 51 first movable side fixed plate 52 second movable side fixed plate 53 stator support Block 54 Balance weight 7 Air bearing 9 First side force detection load cell 11 Second side force detection load cell 13 Thrust detection load cell 15 Mover holding member x x direction y y direction z z direction

Claims (3)

Base and
A movable stage on which a linear motor mounted on the base and capable of moving the mover in a vertical direction is mounted;
Stage supporting means for supporting the movable stage movably in a direction orthogonal to the vertical direction via a fluid,
Detecting means for detecting a force in a direction orthogonal to a vertical direction of the movable stage. 2. The side force measuring device for a linear motor according to claim 1, wherein said detecting means is a load cell. The stage support means includes a plurality of air injection nozzles provided on a lower surface of the movable stage, and a compressed air supply device for supplying compressed air to an upper surface of the base through the plurality of air injection nozzles. 3. The side force measuring device for a linear motor according to claim 1, wherein

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