JP2002159166A - Pole sensor for linear motor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a pole sensor for a linear motor capable of easily positioning a pole position and a pole sensor position of the motor by preventing an erroneous operation of an output of a Hall element. SOLUTION: The pole sensor for the linear motor comprises a plurality of first pole sensors 11a to 11c disposed in one lateral row at an interval corresponding to 1/3 of a pole pitch of a permanent magnet 2 of the motor to detect a U phase; a V phase and a W phase of the pole positions of the motor; a plurality of second pole sensors 12a to 12c deviated in a direction perpendicular to a direction for disposing the sensors 11a to 11c, and arranged so as to cancel signal changes of the sensors 11a to 11c generated by alternating magnetic fields of the currents flowing to a plurality of armature coils 4; and a pole sensor board 13 provided at a moving element 3 of the motor to mount the sensors and its signal processor.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is used for a feed mechanism of a machine tool and a positioning device of a semiconductor manufacturing apparatus.
The present invention relates to a linear motor in which one of a field pole and an armature is relatively moved as a stator and the other as a moving element, and more particularly to a linear motor pole sensor for detecting a pole position of the linear motor.

[0002]

2. Description of the Related Art Conventionally, it has been used for a feed mechanism of a machine tool or a positioning device of a semiconductor manufacturing apparatus, and is relatively moved with one of a field pole and an armature as a stator and the other as a mover. The resulting linear motor is as shown in FIG. FIG. 5 is a cross-sectional view of a conventional movable magnet type linear motor. In the figure, 18 is a truck, 18a is a running roller, 19 is a transport hanger, 20 is a coil assembly, 2
2 is a fixed coil, 30c is a Hall element, 40 is a guide rail, 40a is a fixed portion, 40b is a rail portion, 50 is a cover, 70 is a mover, 80 is a permanent magnet, and 90 is a movable frame. The one stator side includes a guide rail 40, a coil assembly 20 attached to a fixing portion 40 a formed at an upper end of the guide rail 40, and a detachable cover 50 that covers the coil assembly 20. At the lower end of the guide rail 40, a rail portion 40b having a U-shaped cross section for running the running roller 18a is formed. The other mover 70 is connected to the coil assembly 20.
The permanent magnet 80 facing the fixed coil 22 built therein and the movable frame 90 sandwiching the permanent magnet 80
A carriage 18 for fixing the movable frame 90; a transport hanger 19 formed integrally with the carriage 18;
And a running roller 18a supported in the vertical direction with respect to. Note that a plurality of permanent magnets 80 are arranged so that magnetic poles are alternately arranged in a direction perpendicular to the paper surface of FIG. Further, Hall elements 30c, 30a, 30b for detecting the polarity of the permanent magnet 80 (30a, 30b are not shown)
Is attached to the coil assembly 20 side. FIG. 6 shows a control circuit configuration of a conventional movable magnet type linear motor. In the figure, 22a to 22f are fixed coils, 30c, 30a and 30b are Hall elements, 60 is a driver circuit, 60a and 60b are switches, and 62 is a microcomputer. Hall elements 30c, 30a, 30b for detecting the polarity of the permanent magnet 80 of the moving element 70
The microcomputer 62 detects the position of the moving element 70 based on the outputs of these Hall elements, and excites the coil assembly 20 via the driver circuit 60. By opening and closing the switches 60a and 60b, the driver circuit 60 sequentially switches the energizing and exciting directions of the fixed coils 22a to 22f as the moving element 70 moves. FIG. 7 shows a positional relationship among the coil assembly 20, the moving element 70, and the Hall elements 30c, 30a, and 30b. Hall elements 30c, 30a, and 30b for detecting the polarity of the permanent magnet 80 of the movable element 70 are arranged on the coil assembly 20 side. The Hall elements 30c, 30a, and 30b are coils 22
a, 22b, 22z and coils 22d, 22e, 22
In order to continuously generate a thrust between the motor f and the permanent magnet 80, a relative position between the motor f and the permanent magnet 80 is detected, and the direction in which the coil is energized is switched. In the conventional example, since the width of the permanent magnet 80 is 24 mm, the Hall element is 8 mm.
The detection is performed at the pitch.

[0003]

However, in the prior art, the coils 22a to 22a flowing when the moving element 70 is accelerated or decelerated are used.
An AC magnetic field is generated by the current f, and the influence of the AC magnetic field affects the Hall elements 30c, 30a, and 30b.
There has been a problem that the Hall element output malfunctions and the reliability is lacking. Further, each of the Hall elements 30c, 30a, 30b
Is mounted on the coil assembly 20 side alone, so that there is a problem that it is extremely difficult to position the pole position of the motor and the Hall element position. The present invention has been made to solve the above-described problem, and can prevent a malfunction of a Hall element output, and can easily perform a positioning between a pole position of a linear motor and a magnetic sensor position. An object of the present invention is to provide a pole sensor for a motor.

[0004]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention is directed to a field pole in which a plurality of permanent magnets are arranged alternately with different magnetic poles, and a magnetic gap between the field pole and a magnetic gap. , The armature having a plurality of three-phase armature coils mounted thereon, one of the field poles and the armature being a stator, and the other being a mover, and the mover being fixed. In the linear motor, which is relatively moved along the longitudinal direction of the armature, the permanent magnets are arranged in a horizontal line at intervals corresponding to 1/3 of the pole pitch P of the permanent magnets, and are the pole positions of the linear motor. A first pole sensor composed of a plurality of magnetic sensors for detecting a U phase, a V phase, and a W phase, and a signal change of the first pole sensor generated by an AC magnetic field of a current flowing through the plurality of armature coils is canceled. I will do it A second pole sensor composed of a plurality of magnetic sensors arranged so as to be deviated at a position orthogonal to a direction in which the plurality of first pole sensors are arranged, and provided on the armature; A pole sensor for a linear motor, comprising: each of the pole sensors; and a pole sensor board on which a signal processing circuit of each of the pole sensors is mounted. According to a second aspect of the present invention, in the pole sensor for a linear motor according to the first aspect, holes for positioning and fixing the pole sensor board with respect to the armature are provided at both ends of the pole sensor board. It is.
According to a third aspect of the present invention, in the pole sensor for a linear motor according to the second aspect, the hole has a length corresponding to １ ／ of a pole pitch P of the permanent magnet.

[0005]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. 1A and 1B show a linear motor according to an embodiment of the present invention, in which FIG. 1A is a front view of the linear motor viewed from a thrust direction, and FIG. 1B is a pole sensor and a pole attached to the moving element shown in FIG. FIG. 2 is a side view of the stator on which the permanent magnets shown in FIG. 1 are arranged. In the figure, 1 is a stator, 2 is a permanent magnet, 3 is a moving element, 4 is an armature coil, 11 is a first pole sensor, 12 is a second pole sensor, and 13 is a pole sensor board. The configuration of the present invention is as follows. As shown in FIG. 2, a plurality of permanent magnets 2 serving as field poles are provided on one of the stators 1 with an adhesive or the like so that the magnetic poles N and S are alternately different along the longitudinal direction of the stator 1. Fixed.
Assuming that the pole pitch of the permanent magnets 2 is P, the permanent magnets 2 are arranged on the stator 1 at intervals corresponding to の of the pole pitch P. The other mover 3 is shown in FIG.
As shown in FIG. 3A, an armature is provided with a plurality of three-phase armature coils 4 mounted thereon while being arranged via a magnetic gap with the stator 1, and is provided via a bearing (not shown). Supported. In addition, the moving element 3 includes
As shown in (a) and (b), the first pole sensor 11 which is a magnetic sensor for detecting the polarity of the permanent magnet 2
Are fixed so as to face the stator 1. This first
Specifically, the pole sensor 11 includes three Hall elements 11
a, 11b, and 11c, corresponding to 1/3 of the pole pitch in the longitudinal direction of the substantially rectangular pole sensor board 13 so that the U-phase, V-phase, and W-phase, which are the pole positions of the linear motor, can be detected. Are arranged in a horizontal line at an interval. Further, the pole sensor substrate 13 has a first AC magnetic field generated by a current flowing through the armature coil 4.
To cancel the erroneous signal output of the pole sensor 11,
A second pole sensor 12, which is a magnetic sensor, is provided so as to be deviated by a predetermined distance L from a mounting position of the first pole sensor 11 in a direction orthogonal to the longitudinal direction of the pole sensor board 13. The second pole sensor 12 has a Hall element 12a,
12b and 12c. The pole sensor substrate 13 is provided with holes 14a at both ends of the substrate for positioning and fixing to the movable element 3, and is fixed to the movable element 3 using screws (not shown).

Next, a signal processing circuit for driving the pole sensor and amplifying the detection signal will be described. FIG. 3 is a block diagram showing a signal processing circuit of the pole sensor. Although not specifically shown on the pole sensor board 13 of FIG. 1B, the signal processing circuit is mounted on the pole sensor board. Hall elements 11a to 11c and 12a to 12c, which are magnetic sensors, are amplifier ICs.
It is driven at a constant voltage by 2A, IC2B and transistors TR1, TR2. The pin numbers 2p and 4p, which are the output pins of the Hall elements 11 and 12, have an inverted output relationship with each other, and the output pins of the Hall elements 11 and 12 are
As shown in FIG. 3, the inverted output pins are connected via a resistor R. For example, in the case of the hall elements 11a and 12a, the pin number 4p of the hall element 11a is connected to the pin number 2p of the hall element 12a via the resistors R2 and R1, and the pin number 2p of the hall element 11a is
The pin number 4 of the Hall element 12a is connected via the resistors R3 and R4.
connected to p. The hall elements 11b and 12b and the hall elements 11c and 12c are similarly connected. As described above, the connection of the Hall elements 11 and 12 is of a differential configuration, and the output signals of the Hall elements 11a, 11b and 11c are output from the pole positions U, V and W of the linear motor.
If the phases match, the Hall elements 12a, 12b, 12c
Has a relationship of u-phase, v-phase, and w-phase, which are inverted signals of the output signals of the Hall elements 11a, 11b, and 11c, and the in-phase output signal can be canceled. The output signals of the Hall elements 11 and 12 are supplied to the comparator IC1.
A, IC1B, and IC1C are formed into a rectangular wave and output to the host controller 5.

Therefore, in the linear motor of the first embodiment, the permanent magnets 2 are arranged in a horizontal row at intervals corresponding to 1/3 of the pole pitch P of the permanent magnets 2, and the U-phase and the V-phase , A first pole sensor 11 composed of a plurality of magnetic sensors for detecting the W phase, and a signal change of the first pole sensor 11 generated by an AC magnetic field of a current flowing through the plurality of armature coils 4 are canceled. A second pole sensor 12 composed of a plurality of magnetic sensors arranged to be deviated at a position orthogonal to a direction in which the plurality of first pole sensors 11 are arranged; Since the sensors 11 and 12 and the pole sensor board 13 on which the signal processing circuit of each pole sensor is mounted are provided, for example, the armature core which flows when the moving element 3 is accelerated or decelerated is provided. AC magnetic field generated by the current Le 4, the Hall element 11a on the pawl sensor substrate 13, 1
1b, 11c, the Hall elements 12a, 12b, 12c respectively corresponding to the Hall elements 11a, 11b, 11c are erroneously generated by the influence of the AC magnetic field generated by the current of the armature coil 4. The output signal can be detected in phase, and the erroneous output signal can be canceled by connecting the differential configuration in the signal processing circuit of the pole sensor. Detection can be performed, and malfunction of the Hall element can be prevented.

FIG. 4 is a side view of a pole sensor substrate according to a second embodiment of the present invention. The second embodiment is different from the first embodiment in that a hole 14b having a length corresponding to １ ／ of the pole pitch P of the permanent magnet, that is, a so-called long hole is provided at both ends of the pole sensor substrate 13. It is. The hole 14
If b is at least 1/3 or more of the pole pitch P, the pole sensor board 13 is screwed onto the mover 3 so that one of the Hall elements 11a, 11b, and 11c matches the U-phase pole position of the linear motor. The position can be easily adjusted in a state temporarily fixed by, for example, not shown). For example, when the Hall element 11b is tightened with a screw or the like at a position corresponding to the U-phase pole position of the linear motor, the Hall element 11c is in the V phase and the Hall element 11a is in the W phase. Whether any of the Hall elements 11a, 11b, 11c matches the U-phase, V-phase, W-phase of the linear motor is set in the host controller, or a changeover switch is arranged on the pole sensor board 13 to switch the switch. Is performed, it is possible to determine the phase of the Hall elements 11a, 11b, 11c. Further, the Hall elements 11a, 11b,
11c are fixed to the U-phase, V-phase, and W-phase, respectively.
P may be the length of b. The second embodiment has a hole 4b having a length corresponding to 1/3 of the pole pitch P of the permanent magnet.
Is provided on the pole sensor board 13, the pole sensor board 13 is temporarily fixed to the movable element 3, and the positioning with respect to the pole position of the linear motor can be performed. It can be done easily. In the second embodiment, the holes 14b are provided at both ends of the pole sensor board 13. However, the position may not be at both ends, and the holes may not necessarily be holes but may have a cut shape. it is obvious.

[0009]

As described above, according to the first embodiment of the present invention, in the linear motor, the linear motors are arranged in a horizontal line at an interval corresponding to 1/3 of the pole pitch P of the permanent magnets. U-phase, V-phase, which are the motor pole positions,
A first pole sensor including a plurality of magnetic sensors for detecting a W phase and a plurality of first pole sensors configured to cancel a signal change of the first pole sensor generated by an AC magnetic field of a current flowing through the plurality of armature coils. A second pole sensor composed of a plurality of magnetic sensors arranged to be displaced in a direction orthogonal to the direction in which the pole sensors are arranged; a second pole sensor provided on the armature; And a pole sensor board on which the signal processing circuit is mounted, so that each hall element constituting the second pole sensor corresponding to each hall element constituting the first pole sensor is generated by the current of the armature coil. An erroneous output signal due to the influence of an AC magnetic field can be detected in the same phase, and the connection of a differential configuration in the signal processing circuit of the pole sensor is eliminated. It makes since it is possible to cancel the erroneous output signal, it is possible to detect only the magnetic field of the permanent magnet 2, it is possible to prevent malfunction of the Hall element. Further, according to the second embodiment of the present invention, since the hole having a length corresponding to at least に of the pole pitch P of the permanent magnet is provided at both ends of the pole sensor substrate, the pole sensor substrate can be used as a movable element. Since the linear motor can be temporarily fixed and positioned with respect to the pole position of the linear motor, the pole position can be easily adjusted and highly accurate positioning can be easily performed.

[Brief description of the drawings]

FIG. 1 is a linear motor showing an embodiment of the present invention,
FIG. 2A is a front view of a linear motor, and FIG. 2B is a side view of a pole sensor and a pole sensor board attached to the moving element shown in FIG. 1A (first embodiment).

FIG. 2 is a side view of a stator on which the permanent magnet shown in FIG. 1 is arranged.

FIG. 3 is a block diagram of a signal processing circuit of the pole sensor.

FIG. 4 is a side view of a pole sensor substrate according to a second embodiment of the present invention.

FIG. 5 is a cross-sectional view of a conventional movable magnet type linear motor.

FIG. 6 shows a control circuit configuration of a conventional movable magnet type linear motor.

FIG. 7 shows a conventional coil assembly 20 and a moving element 70.
And a positional relationship between the Hall elements 30A, 30B, and 30C.

[Explanation of symbols]

Reference Signs List 1 stator 2 permanent magnet 3 mover 4 armature coil 11, 11a, 11b, 11c: Hall element (first pole sensor) 12, 12a, 12b, 12c: Hall element (second pole sensor) 13 Pole sensor substrate 14a Hole part 14b Hole part 15 Host controller IC1A, IC1B, IC1C: Comparator IC2A, IC2B: Operational amplifier TR1, TR2: Transistor R1 to R20: Resistance

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 5H611 AA01 BB09 PP01 PP05 QQ03 RR02 UA01 UA07 5H641 BB06 BB18 BB19 GG02 GG03 GG07 GG24 GG26 GG28 HH02 HH03 HH06 JA01

Claims (3)

[Claims] 1. An armature having a plurality of permanent magnets arranged so that magnetic poles are alternately different from each other, and an armature provided with a plurality of three-phase armature coils arranged through the magnetic gap with the field pole. And a linear motor in which one of the field pole and the armature is a stator and the other is a mover, and the mover is relatively moved along a longitudinal direction of the stator. A plurality of magnetic sensors are arranged in a horizontal row at intervals corresponding to 1/3 of the pole pitch P of the permanent magnets, and include a plurality of magnetic sensors for detecting U-, V-, and W-phases, which are pole positions of the linear motor. One pole sensor and a direction orthogonal to the direction in which the plurality of first pole sensors are arranged so as to cancel a signal change of the first pole sensor generated by an AC magnetic field of a current flowing through the plurality of armature coils. A second pole sensor composed of a plurality of magnetic sensors arranged to be deviated at the position of: and a pole provided on the armature and mounting each of the pole sensors and a signal processing circuit of each of the pole sensors. A pole sensor for a linear motor, comprising: a sensor substrate. 2. A pole sensor for a linear motor according to claim 1, wherein holes are provided at both ends of said pole sensor board for positioning and fixing said pole sensor board with respect to said armature. 3. The pole sensor for a linear motor according to claim 2, wherein the hole has a length corresponding to at least 1/3 of a pole pitch P of the permanent magnet.