JP2001268884A - Linear motor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a linear motor easily manufactured by preventing a complicated wiring, not erroneously detecting a position of a permanent magnet and not giving an influence to a thrust ripple due to the position of the magnet. SOLUTION: A pair of adjacent electromagnets are arranged at a constant distance (interval) in a stator 1, and a magnetic sensor block 3 is disposed in a space in which the interval of the poles is wider by 2L of two poles of poles 22 of the permanent magnet 21 than the constant distance. Accordingly, since coils 11 of positions separated at a distance of integral multiple of L become the same phases, it means that the block 3 is disposed without replacing the phase sequence continued at the other parts as they are. Since a plurality of magnetic sensors 31 are gathered at one place as the block 3, the wirings are simplified, and its manufacture is facilitated. The erroneous detection in the case in which the sensors 31 are disposed in the coils 11 does not occur, and yet the thrust ripple can be reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a linear motor used for transporting a door or the like.

[0002]

2. Description of the Related Art Conventionally, as a linear motor, a coil block in which a plurality of coils are arranged in a row is arranged in a magnetic field, and a current is applied to each coil so as to generate a thrust in a direction to move a mover. As shown in FIG. 5, a stator (coil block) 1 in which a plurality of coils 11 are arranged in a row along the traveling direction, and a stator 1 in which a plurality of magnetic poles are alternately different in the traveling direction. A thrust for moving the mover 2 by interaction with the mover (permanent magnet) 2, a plurality of magnetic sensors 31 for detecting the position of the mover 2, and the permanent magnet is provided. Each coil 1 has a timing corresponding to the position of the mover 2 detected by the magnetic sensor 31.
1 is provided with a control means (not shown) for controlling energization of the motor 1. Here, the distance (interval) between adjacent coils 11 in the moving direction of the mover 2
Is set to a dimension (for example, 10 L / 6) larger than the distance L between the magnetic poles of the mover 2 in the moving direction of the mover 2 and smaller than twice the dimension thereof.

In the above-described conventional linear motor, the timing of energizing the coil 11 is controlled in accordance with the position of the mover 2. The position of the mover 2 detects the magnetic pole of the permanent magnet 21. It is detected by the magnetic sensor 31. The number of phases of the coil 11 is, for example, three phases (U phase, V phase, W phase).
In each phase, the magnetic sensor 31 is arranged near the center of the coil 11 of each phase. That is, the magnetic sensor 31
Are arranged at equal intervals over the entire length of the stator 1.

[0004]

As described above, if the magnetic sensors 31 are arranged at regular intervals over the entire length of the stator 1, the magnetic sensors 31 are arranged in a dispersed manner, and the wiring Becomes complicated and the manufacturing operation becomes troublesome. Also,
In the conventional configuration described above, the magnetic sensor 3
Since the coil 1 is disposed, the coil 1 is easily affected by a magnetic field generated around the coil 11 when the coil 11 is energized, and the position of the mover 2 may be erroneously detected.

On the other hand, as shown in FIG. 6, the present applicant completely removes a plurality of coils 11 arranged in the traveling direction one by one at regular intervals, and concentrates the magnetic sensors 31 in the space. By arranging and forming the magnetic sensor block 3, it is possible to prevent wiring from becoming complicated and to facilitate manufacture, and by arranging the magnetic sensor 31 at a position that is not easily affected by the coil 11, A linear motor in which the position is not erroneously detected has already been proposed (see Japanese Patent Application No. 11-44061).

However, in the linear motor disclosed in the above-mentioned application, since the phase sequence is switched at the portion where the coil 11 is removed, the ripple of the thrust (F on the vertical axis) due to the position of the permanent magnet 21 is reduced as shown in FIG. There is a disadvantage that it becomes larger. That is, FIGS. 7A to 7F show how the energization of the coils 11 of each phase is switched when the mover 2 is moved to the left in the figure, and FIG. (F)
The change in the thrust corresponding to (1) indicates that the ripple generated in the thrust is very large due to the change of the phase sequence in the portion where the magnetic sensor block 3 is arranged, as is apparent from this figure.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and has as its object to prevent the wiring from becoming complicated by arranging a plurality of magnetic sensors in a concentrated manner, thereby achieving manufacturing. By providing a magnetic sensor at a position that is easy and is not easily affected by the magnetic field of the coil, the position of the permanent magnet is not erroneously detected, and a linear motor that does not affect the thrust ripple due to the position of the permanent magnet is provided. Is to do.

[0008]

According to a first aspect of the present invention, there is provided a coil block in which a plurality of coils are arranged along a traveling direction, and a plurality of magnetic poles are arranged along the traveling direction. A permanent magnet disposed opposite to the coil block so as to have alternately different polarities; a magnetic sensor block including a plurality of magnetic sensors for detecting the position of the permanent magnet; and a coil formed by interaction with the permanent magnet. Control means for controlling energization of each coil at a timing according to the position of the permanent magnet detected by the magnetic sensor block so as to generate a thrust for moving the block or the permanent magnet, and at least one adjacent coil interval is provided. A space is provided which is longer than an interval between other adjacent coils by an integral multiple of one magnetic pole of the permanent magnet, and the magnetic sensor block is disposed in this space. Since a plurality of magnetic sensors for detecting the position of the permanent magnets are combined in one place as a magnetic sensor block, when compared to a case where wiring is individually applied to magnetic sensors arranged in a distributed manner, Wiring is simplified and manufacturing is facilitated. Also, in the coil blocks arranged in the traveling direction, at least one adjacent coil interval is longer than the other adjacent coil interval by an integral multiple of one magnetic pole of the permanent magnet. Since the sensor block is arranged, erroneous detection unlike the case where the magnetic sensor is arranged in the coil does not occur, and the phase order of the coil does not change even if the position where the magnetic sensor block is arranged is interposed. Ripple of the thrust can be reduced as compared with a case where one magnetic sensor block is disposed after removing one magnetic sensor block.

According to a second aspect of the present invention, there is provided an electromagnet comprising a coil and an iron core, and a plurality of electromagnets arranged along a traveling direction, and a stator yoke for magnetically coupling the electromagnets. It is composed of a stator, a permanent magnet disposed opposite to the electromagnet such that a plurality of magnetic poles alternately have different polarities along the traveling direction, and a mover yoke for magnetically coupling the plurality of magnetic poles. Mover, a magnetic sensor block including a plurality of magnetic sensors for detecting the position of the mover,
Control means for controlling energization of each coil at a timing corresponding to the position of the mover detected by the magnetic sensor block so as to generate a thrust for moving the mover by interaction with the permanent magnet; A space is provided in which the distance between two adjacent electromagnets is longer than the distance between other adjacent electromagnets by an integral multiple of one pole of the permanent magnet, and the magnetic sensor block is disposed in this space and The block is fixed to the stator yoke, and a plurality of magnetic sensors for detecting the position of the mover are combined in one place as a magnetic sensor block. In comparison with the case where wiring is provided, the wiring becomes simpler and the manufacturing becomes easier. Also, of the electromagnets arranged in the traveling direction,
Since the magnetic sensor block is arranged where at least one adjacent electromagnet interval is longer than the other adjacent electromagnet intervals by an integral multiple of one magnetic pole of the permanent magnet, the magnetic sensor is disposed in the coil. No misdetection occurs when placing the magnetic sensor block, and even if the position where the magnetic sensor block is placed is interposed, the phase order of the coils does not change.
Ripple of thrust can be reduced as compared with the case where one coil is removed and the magnetic sensor block is arranged. Furthermore, since the magnetic sensor block and the plurality of electromagnets can be integrated via the stator yoke, there is no relative displacement between the position of the electromagnet and the position of the magnetic sensor, and more current is supplied to the coils constituting each electromagnet. Switching can be performed with high accuracy.

According to a third aspect of the present invention, in the first or second aspect, a magnetic sensor block is configured by arranging a plurality of magnetic sensors on a printed circuit board. The work is simply to attach the assembly assembled by a machine or the like to a predetermined position, so that the assemblability is further improved.

According to a fourth aspect of the present invention, in the second aspect of the present invention, a magnetic sensor block is formed by arranging a plurality of magnetic sensors on a printed circuit board. The magnets are fixed to the stator yoke with a gap, and the position of the magnetic sensor block can be easily brought close to the mover, so that energization to the coils constituting each electromagnet can be switched with higher accuracy. In addition, by providing a gap between the stator yoke and the magnetic sensor block by the spacer, electrical insulation between the two can be easily performed.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS In this embodiment, as shown in FIGS. 1 to 3, an electromagnet comprising a coil 11 and an iron core 12 and arranged in a plurality in the direction of travel, and a fixed magnetically coupling each electromagnet. The stator 1 constituted by the child yoke 13, the permanent magnet 21 disposed opposite the electromagnet so that a plurality of magnetic poles are alternately different in the traveling direction, and the magnetic poles 22 of the permanent magnet 21 are connected to each other. A movable element 2 including a movable element yoke 23 which is magnetically coupled; a magnetic sensor block 3 including a plurality of magnetic sensors 31 for detecting a relative position of the movable element 2 with respect to the stator 1; And a control circuit block 4 for controlling the energization of each coil 11 at a timing according to the position of the mover 2 detected by the magnetic sensor block 3 so as to generate a thrust for moving the mover 2 due to the interaction with the coil. There.

The stator yoke 13 is formed of a soft magnetic material in an elongated shape along the moving direction of the mover 2, and a plurality of holes (not shown) for fixing an electromagnet are arranged at regular intervals. I have. The coil 11 is wound around a coil bobbin 14 formed of an insulating material such as a synthetic resin, and an electromagnet is inserted by inserting an iron core 12 into a cylindrical hole provided at the center of the coil bobbin 14. Is configured. And a plurality of electromagnets configured in this way are
The stator 1 is formed by fitting one end of the iron core 12 into a hole provided in the stator yoke 13 and fixing it by an appropriate method such as caulking. In this embodiment, the number of phases of the coil 11 is three, and these coils 11 are
The method of energizing each phase is adopted.

The permanent magnet 21 constituting the mover 2 is provided such that a plurality of magnetic poles 22 are alternately different in the moving direction, and the distance (interval) between adjacent magnetic poles 22 is constant. I have. The mover 2 is formed by magnetizing one magnetic body so that a plurality of magnetic poles 22 are formed, or by attaching a plurality of permanent magnets 21 to a mover yoke 23 as shown in FIG. . In a structure in which a plurality of permanent magnets 21 are attached to the mover yoke 23, each permanent magnet 21 forms one magnetic pole 22.

Here, in the present embodiment, the distance (interval) between a pair of adjacent electromagnets in the stator 1 is arranged to be constant, and further, at every constant interval according to the length and the moving distance of the mover 2, A space is provided in which the distance between the electromagnets is wider than the above-mentioned fixed distance by two poles of the magnetic poles 22 of the permanent magnet 21, and the magnetic sensor block 3 is disposed in this space.

The magnetic sensor block 3 includes a printed board 3
2, three magnetic sensors 31 such as Hall elements are arranged on the stator yoke 1 via a spacer 33 made of an insulating material.
3 is fixed at about the same height as the iron core 12 by a spacer 33. Thus, since the magnetic sensor block 3 and the plurality of electromagnets are integrated via the stator yoke 13, there is no relative displacement between the position of the electromagnet and the position of the magnetic sensor 31, and each electromagnet is formed. The energization of the coil 11 can be switched with higher accuracy. In addition, since the magnetic sensor block 3 is configured by arranging the plurality of magnetic sensors 31 on the printed circuit board 32, the work of simply mounting the magnetic sensor block 3 separately assembled at a predetermined position by a component mounting machine or the like is performed. Thus, there is an advantage that the assemblability is further improved. Further, since the magnetic sensor block 3 is fixed to the stator yoke 13 by providing a gap between the magnetic sensor block 3 and the stator yoke 13 by the spacer 33, the position of the magnetic sensor block 3 can be easily brought close to the mover 2. The energization of the coil 11 constituting each electromagnet can be switched with higher precision, and the gap between the stator yoke 13 and the magnetic sensor block 3 is provided by the spacer 33, so that electrical insulation between the two can be easily performed. There are advantages.

On the other hand, the control circuit block 40 is, as shown in FIG. 3, a bridge circuit of a power supply section 41 composed of a DC power supply and six switch elements Q in which, for example, a back-electromotive prevention diode D is connected in anti-parallel. And each phase (U
An output unit 42 for switching between three phases (phase, V-phase, and W-phase), and a control unit 43 for performing switching control of each switch element Q of the output unit 42 are provided. The control unit 43 has, for example, a CPU as a main component, receives a position detection signal from the magnetic sensor 31, and outputs the signal to the output unit 4 based on a predetermined program.
The second switching element Q is sequentially turned on and off. The control circuit block 40 allows current to always flow through the two-phase coils 11 of the three-phase coils 11 of the stator 1,
A traveling magnetic field that moves along the longitudinal direction of the mover 2 is generated between the movable element 2 having the permanent magnet 21 and the traveling magnetic field moves in a substantially linear longitudinal direction with the permanent magnet 21. A thrust that can be obtained can be obtained.

In this embodiment, apart from the electromagnets adjacent to the magnetic sensor block 3 in the stator 1, the interval between each pair of adjacent electromagnets is arranged to be constant, and the interval between the magnetic poles 22 of the mover 2 is also set. There is constant. Assuming that the length of one pole of the magnetic pole 22 of the mover 2 is L, the distance between the electromagnets at a portion where the electromagnets are arranged at a constant pitch is 10
It is configured to be L / 6. The interval between adjacent magnetic sensors 31 in the magnetic sensor block 3 is set to 2L / 3.

The symbols U, V, and W in FIGS. 1 and 2 indicate the phase (excitation phase) of each electromagnet (coil 11). Here, the coil 11 of the phase to which the apostrophe is added means that the winding direction is opposite to the coil 11 of the same phase to which the apostrophe is not added. For example, when the coil 11 corresponding to U is energized clockwise when viewed from above, the coil 11 corresponding to U ′
Is energized counterclockwise. In the illustrated example, the coil 11 is U,
V ′, W, U ′, V, W ′ are arranged in this order, and by sequentially energizing two phases, U, V → V, W → W, U →
Energize cyclically as U, V. In addition, since each coil 11 is Y-connected, two phases, that is, those without an apostrophe or those with an apostrophe are energized in opposite directions. For example, when U and W are excited in FIG.
The coil 11 corresponding to U and the coil 11 corresponding to W are energized in opposite directions. In other words, two adjacent coils 11 in the stator 1 are simultaneously energized in the same direction, and no current is applied to the left and right adjacent coils 11 of the set of two energized coils 11. The pair of left and right coils 11 is energized in opposite directions to each other with the coil 11 not energized therebetween.

A description will be given of when to switch the excitation phase when two phases are energized simultaneously. Here, when the position of each electromagnet when the left end of the electromagnet arranged at the leftmost end in the stator 1 is set to the origin O is taken on the horizontal axis and normalized by the peak value F of thrust generated by each electromagnet, the stator FIG. 4 shows a waveform diagram in which the vertical axis represents the thrust generated in 1. The thrust generated by one coil 11 when the mover 2 travels is equal to the length of two poles of N and S of the permanent magnet 21, that is, two cycles of two poles of the magnetic pole 22. Sine waveform. Here, it is assumed that the waveform of the thrust is a sine wave for convenience. In the present embodiment, the distance between adjacent electromagnets is set to 10 L / 6, so that the thrust F generated by the electromagnets of each phase of U, V, and W
Has a waveform as shown in FIG.
Deviating by 0L / 6 is synonymous with deviating by 2L / 6. In addition, two adjacent phases (U
And V ', W and U', and V and W '), the total thrust generated by the electromagnets of the respective phases may be added up, and this added thrust is indicated by a thick line in FIG. . If the excitation phase is switched at a point where two adjacent lines intersect with each other in the waveform, the efficiency is the highest.

The thrust generated by a one-phase electromagnet becomes maximum when the center of the electromagnet of the phase coincides with the point at which the magnetic pole 22 of the permanent magnet 21 switches in the traveling direction. Referring to the respective waveforms in FIG. 4, for example, the peak of the thrust generated by the electromagnet of W phase coincides with the switching point of the thrust generated by the two-phase electromagnets of V ′ and W and W and U ′. You can see that. That is, when the center of the electromagnet of a certain phase coincides with the switching point of the magnetic pole 22 of the permanent magnet 21, the excitation phase may be switched. Normally, the magnetic sensor 31 detects the switching point of the magnetic pole 22, so that if the magnetic sensor 31 is arranged at the center of the electromagnet, the excitation phase can be switched at the most efficient position. Of course, since the period is 2L, the same effect can be obtained even if the magnetic sensor 31 is arranged at a position shifted from the center of the electromagnet by an integral multiple of 2L. The thrust waveform at the time of switching at such a position is as shown by the thick line in FIG.

In the present embodiment, the interval between some adjacent electromagnets is larger than the interval between other adjacent electromagnets.
And a space for arranging the magnetic sensor block 3 by extending the two poles by 2L. That is, the magnetic sensor block 3 is disposed in a space in which two electromagnets are disposed at a distance of 10 L / 6 + 2 L = 22 L / 6. Here, based on the optimal arrangement condition of the magnetic sensor 31, the magnetic sensor 31 is arranged at an interval of 12L / 6 (= 2L) along the moving direction of the mover 2 from the left W-phase electromagnet as shown in FIG. And the magnetic sensor 31
If the remaining two magnetic sensors 31 are arranged at a distance of 2 L / 3 from each other along the moving direction of the mover 2, the excitation is performed at the same position as when the magnetic sensors 31 are dispersedly arranged at the center of each electromagnet. Phase switching can be performed. At this time, since 2 L of space without the coil 11 can be provided, the permanent magnet 21 having a length of 2 L, that is, 2 poles, is compared with the case where the coils 11 are arranged at regular intervals and the magnetic sensors 31 are dispersed. By arranging the magnetic poles 22 extra, the same thrust can be obtained.

In this embodiment, the distance between adjacent electromagnets in the space where the magnetic sensor block 3 is arranged is longer than the distance between other parts by 2L, and the distance between adjacent electromagnets is a distance that is an integral multiple of L. Since the coils 11 have the same phase, as shown in FIG. 2, the magnetic sensor block 3 is arranged without changing the phase order which is continuous in other portions.

Here, as described in the related art, there is a disadvantage that the ripple of the thrust increases when the phase sequence is switched, and the controllability deteriorates when the thrust ripple further increases. As shown in FIG. 6, in the configuration in which one coil 11 is removed and the sensor block is disposed, the phase order is switched at both ends of the magnetic sensor block 3 and the permanent magnet 2
FIG. 7 shows a thrust waveform when the number of poles is 1. On the other hand, in the present embodiment, when seven magnetic poles 22 are used, a thrust waveform as shown by a bold line in FIG. 4 is obtained, and a thrust ripple is suppressed and a linear motor with high controllability can be configured. .

In this embodiment, the stator 1 is composed of a plurality of electromagnets. However, the same effect can be obtained by using an air-core coil instead of the electromagnet.

[0026]

According to the first aspect of the present invention, there is provided a coil block in which a plurality of coils are arranged in a row along a traveling direction, and a coil block facing a coil block such that a plurality of magnetic poles alternately have different poles in a traveling direction. And a magnetic sensor block including a plurality of magnetic sensors for detecting the position of the permanent magnet, and a thrust for moving the coil block or the permanent magnet by interaction with the permanent magnet. Control means for controlling the energization of each coil at a timing corresponding to the position of the permanent magnet detected by the magnetic sensor block, and the distance between at least one adjacent coil is compared with the distance between other adjacent coils. Since a space longer by an integral multiple of one pole of the magnetic pole is provided, and the magnetic sensor block is arranged in this space, a plurality of positions for detecting the position of the permanent magnet are provided. The magnetic sensors are integrated as a magnetic sensor block in one place, so that the wiring is simpler and easier to manufacture than in the case where wiring is individually applied to the magnetic sensors arranged in a distributed manner. Of at least one adjacent coil among the coil blocks arranged in a row is compared with the intervals of other adjacent coils.
Since the magnetic sensor block is placed where it is extended by an integral multiple of the pole, erroneous detection unlike the case where a magnetic sensor is placed in a coil does not occur, and the position where the magnetic sensor block is placed Since the phase order of the coils is not interchanged even if the magnetic sensor block is interposed, there is an effect that the thrust ripple can be reduced as compared with the case where one coil is removed and the magnetic sensor block is arranged.

According to a second aspect of the present invention, there is provided a stator comprising a plurality of electromagnets comprising a coil and an iron core and arranged in the traveling direction, a stator yoke for magnetically coupling the electromagnets, A permanent magnet disposed opposite the electromagnet such that a plurality of magnetic poles are alternately different poles, a mover including a mover yoke for magnetically coupling the plurality of magnetic poles, and a position of the mover. And a magnetic sensor block having a plurality of magnetic sensors for detecting the position of the mover detected by the magnetic sensor block so as to generate a thrust for moving the mover by interaction with the permanent magnet. Control means for controlling energization of the coil, wherein at least one adjacent electromagnet interval is longer than another adjacent electromagnet interval by an integral multiple of one magnetic pole of the permanent magnet. Since the magnetic sensor block is arranged in this space and the magnetic sensor block is fixed to the stator yoke, a plurality of magnetic sensors for detecting the position of the mover are provided in one place as a magnetic sensor block. Since they are summarized, the wiring is simpler and easier to manufacture compared to the case where wiring is individually applied to the magnetic sensors arranged in a dispersed manner, and at least one of the electromagnets arranged in the traveling direction is arranged. One of the magnetic poles of the permanent magnet is compared with the distance between two adjacent electromagnets to the distance between other adjacent electromagnets.
Since the magnetic sensor block is placed where it is extended by an integral multiple of the pole, erroneous detection unlike the case where a magnetic sensor is placed in a coil does not occur, and the position where the magnetic sensor block is placed Even if the coil is interposed, the coil sequence does not change, so that the thrust ripple can be reduced as compared with the case where one coil is removed and the magnetic sensor block is arranged, and the magnetic sensor is connected via the stator yoke. Since the block and multiple electromagnets can be integrated,
There is no relative displacement between the position of the electromagnet and the position of the magnetic sensor, and there is an effect that energization to the coils constituting each electromagnet can be switched with higher accuracy.

According to a third aspect of the present invention, in the first or second aspect of the present invention, the magnetic sensor block is configured by arranging a plurality of magnetic sensors on a printed circuit board. This is an operation of merely attaching the assembled product to a predetermined position, which has the effect of further improving the assemblability.

According to a fourth aspect of the present invention, in the second aspect of the present invention, a magnetic sensor block is formed by arranging a plurality of magnetic sensors on a printed circuit board, and the magnetic sensor block is interposed between the magnetic sensor block and a stator yoke by a spacer. Since the magnetic sensor block is fixed to the stator yoke with a gap, the position of the magnetic sensor block can be easily brought close to the mover, so that energization to the coils constituting each electromagnet can be switched with higher accuracy. In addition, by providing a gap between the stator yoke and the magnetic sensor block by the spacer, there is an effect that both can be easily electrically insulated.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram illustrating a main part of an embodiment.

FIG. 2 is a schematic configuration diagram showing an overall configuration of the above.

FIG. 3 is a schematic circuit configuration diagram showing a circuit configuration of the above.

FIG. 4 is a waveform diagram for explaining the operation of the above.

FIG. 5 is a schematic configuration diagram showing a main part of a conventional example.

FIG. 6 is a schematic configuration diagram showing a main part of another conventional example.

FIG. 7 is an operation explanatory diagram of the above.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 stator 2 mover 3 magnetic sensor block 11 coil 12 iron core 13 stator yoke 21 permanent magnet 22 magnetic pole 31 magnetic sensor 32 printed circuit board

Continued on the front page (72) Inventor Mitsumasa Mizuno 1048 Kadoma Kadoma, Osaka Prefecture Matsushita Electric Works Co., Ltd. 5H641 BB06 BB19 GG02 GG04 GG08 GG11 GG12 GG17 GG19 GG24 GG26 GG28 HH03 HH05 HH06 HH14

Claims (4)

[Claims] 1. A coil block in which a plurality of coils are arranged in a row along a traveling direction, and a permanent block disposed in opposition to the coil block such that a plurality of magnetic poles alternately have different poles in a traveling direction. A magnet, a magnetic sensor block having a plurality of magnetic sensors for detecting the position of the permanent magnet, and a magnetic sensor block that generates a thrust for moving the coil block or the permanent magnet by interaction with the permanent magnet. Control means for controlling the energization of each coil at a timing according to the position of the permanent magnet, wherein the interval between at least one adjacent coil is an integer of one pole of the magnetic pole of the permanent magnet as compared with the interval between other adjacent coils. A linear motor, wherein a space that is twice as long is provided, and the magnetic sensor block is disposed in this space. 2. A stator comprising a plurality of electromagnets comprising a coil and an iron core arranged in the traveling direction, a stator comprising a stator yoke for magnetically coupling the electromagnets, and a plurality of magnetic poles in the traveling direction. A permanent magnet arranged opposite to the electromagnet so as to have alternate poles alternately, a mover composed of a mover yoke for magnetically coupling a plurality of magnetic poles, and a plurality of movers for detecting the position of the mover A current is supplied to each coil at a timing according to the position of the mover detected by the magnetic sensor block so as to generate a thrust for moving the mover by interaction with the magnetic sensor block having the magnetic sensor and the permanent magnet. Control means for controlling the space between at least one adjacent electromagnet and an adjacent electromagnet, wherein the space is longer than the other adjacent electromagnet by an integral multiple of one pole of the magnetic pole of the permanent magnet. A linear motor having the magnetic sensor block disposed therebetween and the magnetic sensor block fixed to a stator yoke. 3. The linear motor according to claim 1, wherein a magnetic sensor block is formed by arranging a plurality of magnetic sensors on a printed circuit board. 4. A magnetic sensor block is formed by arranging a plurality of magnetic sensors on a printed circuit board, and the magnetic sensor block is fixed to a stator yoke by providing a gap between the magnetic sensor block and a stator yoke by a spacer. The linear motor according to claim 2, wherein: