JP2008141929A - Cylindrical linear motor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a cylindrical linear motor which detects an amount of movement of the cylindrical linear motor itself. <P>SOLUTION: The cylindrical linear motor 1 includes a hollow outer cylinder 11, a plurality of hollow coils 12 arranged at a predetermined portion of an inner face of the hollow outer cylinder 11, a hollow inner cylinder 13 movably penetrating within the hollow coils 12, and a plurality of magnets 14 arranged at a portion corresponding to the hollow coils 12 within the hollow inner cylinder 13. A detector 15 for detecting the amount of movement is installed at a portion 111 in which the hollow coils 12 of the hollow outer cylinder 11 are not installed, and at a perforated portion 131 corresponding to the portion 111 of the hollow inner cylinder 11. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a cylindrical linear motor, and more particularly, to a cylindrical linear motor having a built-in movement distance measuring sensor that detects a movement amount of the cylindrical linear motor itself.

  Unlike a hydraulic cylinder or an air cylinder, a cylindrical linear motor that can selectively excite a cylindrical coil and linearly drive a shaft disposed in the hollow portion of the cylindrical coil is a separate drive force source. Is not used, and is widely used as a small stage actuator (see, for example, Non-Patent Document 1 and Non-Patent Document 2).

  FIG. 4 is a sectional view of a conventional cylindrical linear motor 30, and U-phase, V-phase, W-phase, U-phase, etc. cylindrical coils 31 are arranged along the inner wall of the hollow outer cylinder 32.

  A hollow inner cylinder 34 is disposed in the hollow portion of the cylindrical coil 31, and a plurality of permanent magnets 33 are stacked inside the hollow inner cylinder 34.

  In the cylindrical linear motor 30 configured as described above, when the cylindrical coil 31 is excited in the order of U phase, V phase, W phase, U phase,..., The hollow outer cylinder 32 moves in one direction with respect to the hollow inner cylinder 34. When the cylindrical coil 31 is excited in the order of W phase, V phase, U phase, W phase,..., The hollow outer cylinder 32 moves in the opposite direction with respect to the hollow inner cylinder 34.

  FIG. 5 is a configuration diagram of a stage to which a conventional cylindrical linear motor 30 is applied. Both ends of the hollow inner cylinder 34 are fixed to a support base 35 fixed to a substrate 39.

  A guide 37 is installed on both sides of the hollow inner cylinder 34 in parallel with the hollow inner cylinder 34, and a slider 38 is installed above the guide 37 so as to be movable with respect to the guide 37.

  A stage 36 is fixed to the upper surfaces of the hollow outer cylinder 32 and the slider 38.

Since the hollow inner cylinder 34 is fixed to the substrate 39, when the hollow outer cylinder 31 moves, the stage 36 also moves. The movement amount of the stage 36 is measured by a movement amount measuring device such as a linear encoder (not shown) attached to the stage 36.
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  However, since the conventional cylindrical linear motor is not equipped with a movement amount detector and cannot measure the movement amount of the cylindrical linear motor itself, the problem is that the movement amount of the stage cannot be accurately controlled. was there.

  The present invention has been made to solve the conventional problems, and an object of the present invention is to provide a cylindrical linear motor that can detect the movement amount of the cylindrical linear motor itself.

  A cylindrical linear motor according to a first aspect of the present invention includes a hollow outer cylinder, a plurality of hollow coils disposed in a predetermined portion of the inner surface of the hollow outer cylinder, and a hollow inner cylinder that movably penetrates through the hollow coil. A cylindrical linear motor including a plurality of magnets installed in a portion corresponding to the hollow coil inside the hollow inner cylinder, wherein the hollow outer cylinder is a portion where the hollow coil is not installed A movement amount detector is installed in the installation part and the perforation part corresponding to the non-installation part of the hollow inner cylinder.

  With this configuration, the movement amount of the cylindrical linear motor itself can be measured.

  A cylindrical linear motor according to a second aspect of the present invention includes a light emitting unit and a light receiving unit in which the movement amount detector is attached to the non-installation part with the hollow inner cylinder interposed therebetween, and a transparent scale plate attached to the punching part. It has the structure containing these.

  With this configuration, the movement amount can be detected by the light transmission type detector.

  In the cylindrical linear motor according to a third aspect of the present invention, the scale plate is attached to a moving amount measurement scale that is graduated at predetermined intervals over the entire length of the scale plate, and a specific portion of the scale plate. A configuration including an origin scale.

  With this configuration, not only the amount of movement but also the origin of the cylindrical linear motor can be detected.

  The cylindrical linear motor according to a fourth aspect of the invention has a configuration in which the hollow inner cylinder has a flange that slides on the inner surface of the hollow outer cylinder at a boundary position between the portion including the magnet and the perforated portion. ing.

  With this configuration, the lubricating oil can be prevented from adhering to the movement amount detector.

  A cylindrical linear motor according to a fifth aspect of the invention has a configuration including a signal processing unit for the movement amount detector stored in the hollow outer cylinder.

  With this configuration, the noise tolerance of the actual movement amount signal can be increased.

  The present invention can provide a cylindrical linear motor having an effect that the movement amount of the cylindrical linear motor itself can be accurately measured by incorporating a movement amount detector.

  Hereinafter, embodiments of a cylindrical linear motor according to the present invention will be described with reference to the drawings.

  A perspective sectional view of the cylindrical linear motor of the embodiment is shown in FIG.

  That is, the cylindrical linear motor 1 according to the present invention includes a hollow outer cylinder 11, a plurality of hollow coils 12 disposed on a predetermined portion of the inner surface of the hollow outer cylinder 11, and a hollow that penetrates through the hollow coil 12 movably. An inner cylinder 13, a plurality of magnets 14 installed in a portion corresponding to the hollow coil 12 inside the hollow inner cylinder 13, and a non-installation portion 111 which is a portion where the hollow coil 12 of the hollow outer cylinder 11 is not installed. The movement amount detector 15 is installed in the perforated part 131 corresponding to the non-installed part 111 of the hollow inner cylinder 11.

  The perforated part 131 of the hollow inner cylinder 13 is formed in a flat plate shape in which the upper part and the lower part of the hollow inner cylinder 13 are removed and the central part is opened.

  The movement amount detector 15 includes a light emitting unit 151 and a light receiving unit 152 that are attached to the non-installation unit 111 with the hollow inner cylinder 13 interposed therebetween, and a transparent scale plate 153 that is attached to the perforated unit 131.

  The light emitting unit 151 is, for example, a light emitting diode, and the light emitted from the light emitting unit 151 passes through the scale plate 153 and reaches the light receiving unit 152. The light receiving unit 152 is, for example, a photodiode.

  The scale plate 153 is graduated with a moving amount measurement scale 154 that is graduated at predetermined intervals over the entire length of the scale plate 153, and an origin scale 155 that is attached to a specific location of the scale plate 153. The moving amount measurement scale 154 is formed at the center of the scale plate 153 at intervals of 0.5 micrometers, for example, and the origin scale 155 is formed at specific locations on both side ends of the scale plate 153.

  Accordingly, the light receiving unit 152 is installed on both sides of the movement amount measurement photodiode 156 that receives the light transmitted through the movement amount measurement scale 154 at the center and the movement amount measurement photodiode 156, and passes through the origin scale 155. It includes a first origin detection photodiode 157 and a second origin detection photodiode 158 that receive light.

  FIG. 2 is a block diagram showing the configuration of the cylindrical linear motor 1 and the driving unit that drives the cylindrical linear motor 1 according to the present invention. The light receiving unit 152 is connected to the signal processing unit 21, and the signal processing unit 21. Outputs a movement amount which is an origin detection signal and an analog signal.

  That is, the signal processing unit 21 includes an origin signal generation unit 211 that generates an origin signal based on signals output from the first origin detection photodiode 157 and the second origin detection photodiode 158, and a movement amount measurement. And a movement signal generation unit 212 that generates a movement signal indicating the actual movement amount and the actual movement direction based on the signal output from the photodiode 156.

  The movement signal generation unit 212 may output a two-phase pulse or may output an actual movement amount as an analog signal. However, if the movement signal generation unit 212 outputs a two-phase pulse, the actual movement amount A pulse counter or the like that converts the signal into an analog signal is required.

  The control unit 22 takes in the target movement amount given from the outside and the actual movement amount output from the signal processing unit 21, and based on the deviation calculation unit 221 that calculates the deviation between the target movement amount and the actual movement amount and the deviation. And a drive unit 222 that excites the U phase, V phase, and W phase of the hollow coil 12 in a predetermined order.

  When the hollow coil 12 is excited, an attractive force and a repulsive force act between the hollow coil 12 and the magnet 14 stored in the hollow inner cylinder 13, and the hollow outer cylinder 11 and the hollow inner cylinder 13 move relative to each other. .

  When the target movement amount and the actual movement amount coincide with each other, the deviation becomes zero and the excitation of the hollow coil 12 stops.

  In the cylindrical linear motor 1 according to the present invention, since the hollow inner cylinder 13 moves through the hollow portion of the hollow coil 12, a lubricating oil is filled to reduce the friction between the hollow coil 12 and the hollow inner cylinder 13. However, if the lubricant is attached to the movement amount detector 15, the detection accuracy is deteriorated. Therefore, it is necessary to prevent the lubricant in the hollow coil 12 portion from entering the movement amount detector 15.

  Therefore, the hollow inner cylinder 13 of the cylindrical linear motor according to the present invention is provided with a flange 132 that slides on the inner surface of the hollow outer cylinder 11 at the boundary position between the portion including the magnet 14 and the perforated portion 131.

  By providing the flange 132, it is possible to prevent the lubricating oil from entering the movement amount detector 15, so that the power source for the signal processing unit 21 and the light emitting unit 151 can be incorporated into the hollow outer cylinder 11, and the signal The noise resistance can be increased by increasing the current of the two-phase pulse or analog signal output from the processing unit 21.

  In the above configuration, the gap between the hollow outer cylinder 11 and the hollow inner cylinder 13 is adjusted when the cylindrical linear motor 1 is attached to the driven body that is a stage, for example. It is necessary to ensure accuracy.

  Therefore, in the cylindrical linear motor 1 according to the present invention, the first bearing 161 and the second bearing 162 that support the hollow inner cylinder 13 are provided at both ends of the hollow outer cylinder 11 to simplify the mounting of the cylindrical linear motor 1. Is possible.

  FIG. 3 is a cross-sectional view of the cylindrical linear motor 1 according to the present invention, in which the first bearing 161 on the magnet 14 storage side is a ball spline. Here, the ball spline is preferably a circulation type ball spline.

  The second bearing 162 on the movement amount detector installation side only needs to allow the movement of the hollow inner cylinder 13 in the axial direction.

  Furthermore, in the cylindrical linear motor 1 according to the present invention, the magnetic force is enhanced by inserting the soft magnetic plate 16 between the magnets 14 stored in the hollow inner cylinder 13.

  In the above embodiment, the movement amount detector is assumed to be optical, but a magnetic scale and a differential transformer (LVDT) can also be applied as the movement amount detector.

  As described above, the cylindrical linear motor according to the present invention has an effect of being able to detect the movement amount of the cylindrical linear motor itself, and is effective as a linear actuator or the like.

The perspective sectional view of the embodiment of the cylindrical linear motor concerning the present invention The block diagram which shows the structure of the drive part which drives the cylindrical linear motor and cylindrical linear motor which concern on this invention Sectional drawing of the cylindrical linear motor concerning this invention Sectional view of a conventional cylindrical linear motor Configuration diagram of a stage using a conventional cylindrical linear motor

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Cylindrical linear motor 11 ... Hollow outer cylinder 12 ... Hollow coil 13 ... Hollow inner cylinder 14 ... Magnet 15 ... Movement amount detector 132 ... １５ 151 ... Light emission part 152 ... Light receiving part 153 ... Scale plate 154 ... For movement amount measurement Scale 155 ... Origin scale 156 ... Movement amount measurement photodiode 157 ... First origin detection photodiode 158 ... Second origin detection photodiode

Claims (5)

A hollow outer cylinder,
A plurality of hollow coils disposed on a predetermined portion of the inner surface of the hollow outer cylinder;
A hollow inner cylinder movably penetrating through the hollow coil;
A cylindrical linear motor including a plurality of magnets installed in a portion corresponding to the hollow coil inside the hollow inner cylinder,
A cylinder in which a movement amount detector is installed in a non-installation part which is a part where the hollow coil of the hollow outer cylinder is not installed and a perforation part corresponding to the non-installation part of the hollow inner cylinder. Type linear motor. 2. The cylindrical linear device according to claim 1, wherein the movement amount detector includes a light emitting part and a light receiving part that are attached to the non-installation part with the hollow inner cylinder interposed therebetween, and a transparent scale plate that is attached to the perforation part. motor. The scale plate is
A scale for measuring the amount of movement with a scale attached at predetermined intervals over the entire length of the scale plate;
The cylindrical linear motor according to claim 2, including an origin scale attached to a specific location of the scale plate. The hollow inner cylinder is
2. The cylindrical linear motor according to claim 1, further comprising a flange that slides on an inner surface of the hollow outer cylinder at a boundary position between the portion including the magnet and the perforated portion. The cylindrical linear motor according to any one of claims 1 to 4, further comprising a signal processing unit for the movement amount detector stored in the hollow outer cylinder.

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