JPH1052027A - Brushless dc linear motor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a small-sized brushless DC linear motor whose cogging force in its stopping or running position is reduced. SOLUTION: This linear motor has a stator block 1 comprising both a stator case 2 with a nearly lateral-U-shaped section and two flat-plate-form magnets 3 provided opposing their poles of the same kind to each other, and has a movable element block 4 comprising both a position sensor 9 and an armature 5 having both a coil 7 and a yoke 6 with an erected piece 61 opposed to nearly lateral-U-shaped pieces 60a opposite to each other. In this case, the standing piece 61 is so formed that the width of its portion opposed to the permanent magnets 3 becomes larger toward the moving direction of the movable element block 4 than the width of its portion with the wound coil 7.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a brushless DC linear motor for conveyance.

[0002]

2. Description of the Related Art Recently, linear motors are often used for conveying electric curtains, automatic doors, and the like. On the movable side, there are a movable magnet type using a magnet and a movable coil type using a coil on the movable side. In the moving coil linear motor, the brushless DC linear motor that controls the direction of current supply to the movable coil without using a brush has no problem of life due to abrasion of the brush.
Various structures have been proposed, such as that disclosed in Japanese Patent Publication No. 7-46895.

As shown in FIG. 9, the DC brushless linear motor disclosed in the above publication has a long rail 2 forming a stator block and having a substantially U-shaped cross section, and having different poles in a thickness direction and a longitudinal direction. And two movable permanent magnets, which are magnetized so that different poles are present alternately at regular intervals and are disposed so that different magnetic pole faces face each other on the side wall of the rail, and a mover block. A flat coil 7 having an air core disposed along the magnetic pole faces of the permanent magnets 3, 3; and a longitudinal direction of the flat coil 7 and the permanent magnets 3, 3 for switching the energization of the flat coil 7. And a sensor (not shown) for detecting the relative position.

The above-mentioned flat coils 7 are connected in the longitudinal direction, and the energization terminals are connected in a star connection or a delta connection to form a mover block as the coil unit 4. The three flat coils 7 are arranged in the longitudinal direction based on a predetermined dimension determined by the pitch between the magnetic poles in the longitudinal direction of the permanent magnets 3. Three sensors are arranged in the longitudinal direction based on a predetermined dimension determined by the pitch between the magnetic poles in the directions to form a sensor unit. The sensor unit is integrated with the coil unit 4, and a position detection signal from the sensor is input to a not-shown energization switching unit to switch energization to each flat coil 7. As a result, the winding portions of at least two flat coils 7 of each coil unit 4 corresponding to the magnetic pole surfaces of the permanent magnets 3, 3 are provided with the framing left hand determined by the relationship with the polarities of the magnetic pole surfaces of the permanent magnets 3, 3. Is generated, and the permanent magnet and each coil unit relatively move in the longitudinal direction.

[0005] In the above, in order to obtain a large transport thrust, it is necessary to add a coil unit. Therefore, in order to obtain a large transport thrust with a small number of units, the applicant has to use a cross section as shown in FIG. Is magnetized such that a substantially U-shaped long stator case 2 and a different pole are present in the thickness direction and the different poles are alternately present at regular intervals in the longitudinal direction. A stator block 1 having two flat permanent magnets 3 and 3 disposed so that the same poles are opposed to each other, and an opposing piece 6c is disposed between a substantially U-shaped opposing piece 6c. Yoke 6 having standing pieces 6b
And an armature 5 having a coil 7 wound on the standing piece 6b, and a relative position detection in the longitudinal direction between the armature 5 and the permanent magnets 3, 3 for controlling the direction of energization to the coil 7. A position sensor 9 fixed to a guide plate 8 or the like, and the opposing side surfaces of the opposing piece 6c and the standing piece 6b and the detection surface of the position sensor 9 face the side surfaces of the permanent magnets 3, 3. A brushless DC linear motor including the mover block 4 disposed therein has been devised.

In the above-described motor, the driving force of the linear motor is based on the magnetic attraction (repulsion) between the yoke 6 and the permanent magnets 3, 3, and the transport thrust is higher than that of the aforementioned electromagnetic force. Is obtained. As a result, in an automatic door or the like, the yoke 6
On the other hand, it is necessary to make an adjustment to reduce a pulsating force called a cogging force, which is a pulsating thrust caused only by the force applied from the permanent magnets 3 and 3 except for the action of the magnetic field by the coil 7. Then, for example, the shape of the permanent magnets 3, 3 is changed only near the stop position, and the gap distance between the opposing surfaces of the armature 5 of the mover block 4 and the permanent magnets 3, 3 of the stator block 1 is changed. Measures are conceivable.

[0007]

The above-described linear motor is required to have various lengths in, for example, an automatic door. Therefore, when changing the gap interval between the stator block and the permanent magnet, an adjusting member for changing and setting the gap interval for each transport length is required. As a result, the parts cost was high.

The present invention has been made in view of the above circumstances, and it is an object of the present invention to provide a small-sized brushless DC linear motor having a small cogging force at a stop position or a running position.

[0009]

According to a first aspect of the present invention, there is provided a brushless DC linear motor according to the first aspect, wherein a long stator case having a substantially U-shaped cross section and a different pole in a thickness direction are provided. Two permanent magnets, which are magnetized so that different poles are alternately present at regular intervals in the longitudinal direction, and are arranged on the stator case so that the same poles face each other at a predetermined interval, An armature having a stator block, a yoke having a standing piece facing the facing piece in the middle of the substantially U-shaped facing piece, and an armature having a coil wound on the standing piece; A position sensor for detecting the relative position of the armature and the permanent magnet in the longitudinal direction for controlling the direction of conduction, and having a facing surface of the facing piece and the standing piece and a detection surface of the position sensor; Mover block is disposed facing the side surface of the permanent magnet. In the brushless DC linear motor comprising: the standing piece is formed so that a portion facing the permanent magnet has a wider width in a moving direction of the mover block than a portion around which the coil is wound. I have.
As a result, the portion where the standing piece faces the permanent magnet is formed with a wider width in the moving direction of the mover block than the portion around which the coil is wound, and the gap between the adjacent yoke is formed. As a result, the rate of change of the magnetic flux applied from the permanent magnet decreases.

In the brushless DC linear motor according to a second aspect, the standing piece according to the first aspect is a separate member fixed to the yoke main body forming the opposed piece. Thereby, after forming the coil, it can be mounted on the standing piece of another member.

According to a third aspect of the present invention, there is provided a brushless DC linear motor, wherein at least two of the armatures are integrally formed. Thus, at least two armatures are integrally formed, and there is no need to position and fix each armature to the base, resulting in a simple configuration.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a first embodiment of a brushless DC linear motor according to the present invention will be described with reference to FIGS. 1 and 7, and a second embodiment will be described with reference to FIG.

[First Embodiment] FIG. 1 is a sectional view of a brushless DC linear motor according to a first embodiment.
FIG. 2 is a perspective view of the permanent magnet of the DC brushless linear motor shown in FIG. FIG. 3 is an exploded perspective view of the armature of the DC brushless linear motor shown in FIG. FIG.
FIG. 2 is an exploded perspective view of the entire DC brushless linear motor shown in FIG. 1. FIG. 5 is a wiring diagram of coils of the DC brushless linear motor shown in FIG. FIG. 6 is a schematic configuration diagram of a controller that drives the DC brushless linear motor shown in FIG. FIG. 7 is an explanatory diagram of the positional relationship between the armature and the permanent magnet of the DC brushless linear motor shown in FIG.

Reference numeral 1 denotes a stator block, and a stator case 2
And a permanent magnet 3. As shown in FIG. 1, the stator case 2 is provided with permanent magnets 3, which will be described later, and is formed by extrusion molding of aluminum or the like to support a movable block 4 which will be described later in a movable state. The cross section is formed in a substantially U-shaped long cylindrical shape. The stator case 2 is formed into a long cylindrical shape having a substantially U-shaped cross section of a predetermined width by the upper wall 2a, the side walls 2b, 2b and the support walls 2c, 2c on the opening side. The block 4 is a storage room for movably storing the block 4. Therefore,
Support grooves 2d, 2d for supporting the permanent magnets 3, 3 at a predetermined interval in the center of the inner surface of the upper wall 2a, and support walls 2c, 2c
Has an opening 2e at the center. Also, 2f, 2f
Is a guide portion of the mover block 4 for preventing the permanent magnets 3, 3 from being attracted by contact with the permanent magnets 3 by swaying at the time of movement, and is formed with a predetermined width and depth. .

As shown in FIG. 2, the permanent magnets 3, 3 are plate-like magnetized such that different poles are present in the thickness direction and different poles are present alternately at a constant interval L / 2 in the longitudinal direction. belongs to. Then, by fixing the support grooves 2d, 2d of the stator case 2 by appropriate means such as press-fitting or bonding, the same poles are opposed at a predetermined interval over almost the entire length of the stator case 2, and the longitudinal direction is Are arranged so that different poles are present alternately.

Reference numeral 4 denotes a mover block, which comprises an armature 5, guide plates 8, 8, a magnetic sensor 9, and a base plate 10 as main constituent members. Further, the linear motor of this embodiment has three armatures 5, 5, and 5 for three-phase driving, and coils 7 described later are respectively connected to each other and each of them has a predetermined interval. One unit of the mover block 4 is formed by being disposed on the plate 10. This mover block 4 is used in such a manner that a number of units required by gravity, such as a door to be conveyed, are connected in a longitudinal direction at predetermined intervals, but in the present embodiment, three units are used. A mover block 4 is provided continuously.

The armature 5 has a yoke 6 and a coil 7 wound around a standing piece 61 of the yoke 6 which will be described later.

The yoke 6 is made of a magnetic metal material, for example, by cutting, so that the ends 60b, 60b of the substantially U-shaped opposed pieces 60a, 60a are formed to approach inward and approach. And an upright piece 61 that engages with an engagement hole 60c provided in an intermediate portion of the yoke main body 60. The standing piece 61 has a portion facing the permanent magnets 3 and 3 has a wider width in a moving direction of the mover block than a portion around which a coil 7 described later is wound. The yoke main body 60 and the standing piece 61 may be formed by directly forming a magnetic metal material by, for example, sintering or the like in addition to the above-described cutting.

The coil 7 has a winding body 7b of a bobbin 7a made of a synthetic resin or the like, and a soft copper wire whose surface is coated with an insulating layer, for example, is wound around the U-shaped opening side of the yoke 6, ie, the upper end. It is formed by winding as a side. As shown in the wiring diagram of FIG. 5, the start end and the end of the winding end of the coil 7 have the same relative positions of the three mover blocks 4, for example, the start ends are connected and the end ends. All units are connected collectively and star-connected. In this connection, predetermined winding ends are connected to each other by a wiring pattern of a printed board (not shown), and wired via a flexible printed board or the like having flexibility toward a control device 11 described later. You.

In the armature 5, the width of the opposed pieces 60a of the yoke main body 60 of the yoke 6 in the longitudinal direction and the outer shape of the wound coil 7 are the same in the longitudinal direction of the permanent magnet 3. It is set appropriately so as to have a value smaller than 1/3 of the interval pitch L. In the assembly, the bobbin 7 of the coil 7 is attached to the standing piece 61 provided on the yoke main body 60.
The through-hole 7c provided in the winding drum part 7b of a is inserted and fitted. The armature 5 has end portions 60b, 60a of the opposing pieces 60a, 60a of the yoke 6, depending on the direction of the current flowing through the coil 7.
As for the magnetic pole b, when one is an N pole, the other is also an N pole, and when one is an S pole, the other forms an S pole.

The guide plates 8 and 8 are for positioning the yoke 6 together with a base 10 to be described later. The guide plates 8 and 8 are made of a nonmagnetic material such as a synthetic resin material and have a length smaller than the pitch dimension L in the longitudinal direction. It has a recess 8a formed with an interval P and a guide ridge 8b, and is formed. Further, the guide plate 8 is provided with a fixing portion 8c for fixing a magnetic sensor 9 described later at a predetermined position in the longitudinal direction at the same interval P as the predetermined interval P.

The magnetic sensor 9 is a position sensor for detecting the relative position of the armature 5 and the permanent magnet 3 in the longitudinal direction in order to control the direction in which the coil 7 is energized. In addition, a magnetic diode element that converts a change in a magnetic field caused by the permanent magnet 3 into an electric signal is used. The magnetic sensor 9 may use, for example, a magnetoresistive element or a Hall element in addition to the magnetic diode.
Further, a marking based on, for example, a black and white color change is applied to the surface of the permanent magnet 3 facing the sensor, and an optical projection / reception unit using infrared light capable of optically detecting the marking and detecting the relative position. It may be a position detection sensor. Three magnetic sensors 9 are fixed to the fixing portion 8c of the guide plate 8 and disposed.
Then, a change in the magnetic flux in the vicinity of the arrangement is detected, and a detection signal is output to the control unit 11c of the control device 11 shown in FIG. 5 are detected.

The base plate 10 is for positioning and arranging the armatures 5 at a predetermined pitch interval. The base plate 10 is made of a non-magnetic material such as a synthetic resin material and has a width smaller than the U-shaped width of the stator case 2. A recess 10a formed at a predetermined interval P with a small width, a length smaller than the pitch dimension L in the longitudinal direction, and a ridge 10b on which a conveyed object is fixedly attached to the through-hole 10c and vertically suspended. And is molded. The recess 10a
The armature 5 is fixed thereto, and is a rectangle slightly larger than the longitudinal width of the yoke main body 60 of the yoke 6 and the outside dimensions of the opposing pieces 60a, 60a, and has a predetermined depth. In addition,
In this embodiment, the recess 10
The predetermined distance P between a and the recess 8a and the fixing portion 8c of the guide plate 8 is set to L / 3. The guide plate 8 and the base plate 10 may be made of a non-magnetic metal material such as aluminum, for example, in addition to the above-mentioned synthetic resin material.

As shown in FIG. 3, after the bobbin 7a is inserted into the upright piece 61, the lower end of the upright piece 61 is fitted into the engaging hole 60c of the yoke main body 60, as shown in FIG. It is formed by sticking. The yoke main body 6 is inserted into the recess 10a of the base 10.
0 is provided with three at a predetermined interval P. Further, the ends 60b, 60b are similarly positioned at a predetermined interval P by the recess 8a of the guide plate 8, and form one unit of the mover block 4. Armature 5
The three units are connected and movably disposed inside the stator case 2.

The brushless DC linear motor has a power supply section 11a as a DC power supply for exciting the coil 7, an output section 11b, and a control section 11c shown in FIG.
The current supplied to the coil 7 is controlled by the control device 11 which is current control means having the following. The output unit 11b
A bridge circuit for switching and outputting the excitation phase of the coil 7 and includes, for example, six switch elements Q and a back electromotive prevention diode D. The control unit 11c sequentially controls each switch element Q of the output unit 11b, and includes, for example, a CPU circuit, receives a detection signal of the position of the mover block 4 from the magnetic sensor 9, and receives a signal based on a predetermined program. To sequentially open and close the switch element Q of the output unit 11b.
The control device 11 controls two of the three armature coils a1 to a3, b1 to b3, and c1 to c3 of the armature coils 7 of the three units of the mover block 4 of the brushless DC linear motor. When a current is always supplied, a thrust that can move in a substantially linear longitudinal direction can be obtained.

Next, the operation of the above-described brushless DC linear motor will be described with reference to FIG. First, when a DC voltage having a predetermined voltage value is applied to the coil 7 from the control device 11, an exciting current for exciting the yoke 6 flows. Since the coil 7 is wound with the start of winding of the coil as the upper end side of the yoke 6, for example, when a current is passed clockwise, that is, clockwise, the coil 7 facing the side surface of the permanent magnet 3 is wound. The turned upright piece 61 has the S pole and the end 60.
b and 60b are N poles, respectively. When a current is applied in the counterclockwise direction, ie, counterclockwise, the permanent magnet 3
The standing piece 61 on which the coil 7 opposed to the side surface is wound is N
The pole and the ends 60b, 60b are S poles.

Now, when the armature 5 of the mover block 4 and the permanent magnets 3, 3 of the stator block 1 are in the positions shown in FIG. 7A, an exciting current is applied to the coils 7 of a and c at this time. And the yoke 6 of the armature 5 having the signs of a and c.
The polarity of the surface of the standing piece 61 facing the permanent magnet 7 is shown in FIG.
The state shown in FIG. Therefore, the armature 5 having the coils 7 of the signs a and c and the permanent magnet 3,
3, an attractive force is generated between the magnetic poles facing each other, and a repulsive force is generated between the magnetic poles adjacent thereto, so that a propulsive force acts on the permanent magnets 3, rightward in the figure.

Next, when the mover block 4 moves rightward by the above-mentioned propulsive force and moves to the position shown in FIG. 7B, the output from the magnetic sensor 9 is switched, and the coils b and c are switched. Excitation current is supplied to b and c of the coil 7, and b
7B, the polarity of the surface of the armature 5 facing the permanent magnet 7 of the standing piece 61 of the yoke 6 of the armature 5 is set to the state shown in FIG. 7B. Accordingly, in the same manner as in the above case, the armature 5 having the coils 7 of the signs b and c and the permanent magnet 3,
3, a repulsive force is generated between the magnetic poles facing each other, and an attractive force is generated between the magnetic poles adjacent to each other, and a propulsive force acts on the permanent magnets 3, 3 in the right direction in the figure.

As described above, the relative position in the longitudinal direction between the armature 5 of the mover block 4 and the permanent magnets 3 of the stator block 1 is determined by the output of the magnetic sensor 9 as a position sensor. When the magnetic pole of the yoke 6 of the armature 5 is energized while the energizing direction of the coil 7 is switched, FIG.
6 (f). In any case, the propulsion force continuously acts on the right side of the permanent magnet 6 on the same principle as the above-described case. That is, a, b, c of the three-phase coil 7
A constant thrust is obtained by constantly supplying a current to the two phases.

The magnitude of the thrust is determined by the current flowing through the coil 7, that is, the magnetizing current for magnetizing the yoke 6.
It changes by the magnetic attraction (repulsion) force determined by the size of the magnetic pole generated on the end face of the standing piece 61 and the end portions 60b, 60b, and the size of the magnetic field by the permanent magnets 3,3.
Therefore, in order to increase this magnetic force, the facing piece 6
The distance between the side surface of the permanent magnet 3 and the side surfaces of the permanent magnets 3 and 3 is set as small as possible to set the relative position of the permanent magnet 3 and the armature 5. Also,
Ends 60b, 6 of opposed pieces 60a, 60a of yoke main body 60
0b is formed so as to approach the standing piece 61 and reduce the magnetic resistance. At the same time as the magnetic force increases, the gap between the yoke 6 and the adjacent yoke 6 is reduced, so that the rate of change of the magnetic flux applied from the permanent magnets 3 is reduced. In order to suppress the fluctuation of the force acting from the permanent magnets 3, 3 on the standing piece 61 and the end 60b, the end face of the standing piece 61 and the end 60b, 60b facing the permanent magnet 3, 3 It is configured to have a wider width in the moving direction of the mover block than the portion where the coil 7 is wound. In the case where the propulsive force is obtained in the left direction in the drawing, that is, in the reverse direction, the timing of the energization switching by the control device 11 is changed to cope with the problem.

According to the brushless DC linear motor described above, the portion where the standing piece 61 faces the permanent magnets 3 has a wider width in the moving direction of the mover block 4 than the portion where the coil 7 is wound. Since the air gap between the yoke 6 and the adjacent yoke 6 is small and the rate of change of the magnetic flux applied from the permanent magnets 3 is reduced, the standing piece 61 and the end 60b of the yoke 6 are formed. In contrast, the fluctuation of the force acting from the permanent magnets 3 becomes small, and the cogging force at the stop position or the traveling position becomes small. In addition, the standing piece 61
Is a separate member that is fixed to the yoke main body 60 forming the opposing piece 60a, so that the coil 7 can be wound around the bobbin 7a and formed, and then attached to the standing piece 61, facilitating assembly.

[Second Embodiment] FIG. 8 is an exploded perspective view of an armature according to a second embodiment.

This brushless DC linear motor differs from the first embodiment only in the configuration of the armature, and the other components are the same as those in the first embodiment. The armature 5 includes three armatures forming one unit of the mover block 4 as at least two of the armatures 5 of the first embodiment are integrally formed. Has formed. As in the first embodiment, the mover blocks 4 of three units are connected in series.

The yoke 6 is made of a magnetic metal material, for example, formed by cutting.
And an upright piece 61 that engages with an engagement hole 60c provided in an intermediate portion of the yoke main body 60. The yoke main body 60 includes three sets of substantially U-shaped opposed pieces 60a, 60a.
Are divided by slits 60e with a width appropriately set so as to be smaller than 1/3 of the pitch L between the same poles in the longitudinal direction of the permanent magnet 3, and the end 60
b, 60b are formed continuously so as to approach inward. A slit 60d is formed in an intermediate portion between the opposing pieces 60a, 60a, adjacent to the engaging hole 60c, for alternately dividing the magnetic circuit generated at the time of excitation with the engaging hole 60c. The standing piece 61 is formed such that a portion facing the permanent magnets 3 has a wider width in a moving direction of the mover block than a portion around which a coil 7 described later is wound. And also in this embodiment, the interval P at which the opposing pieces 60a, 60a are
L / 3 is set as in the first embodiment.
The yoke main body 60 and the standing piece 61 may be formed by directly forming a magnetic metal material by, for example, sintering or the like in addition to the above-described cutting.

Therefore, the base plate 10 of this embodiment is similar to that of FIG.
, A width slightly smaller than the U-shaped width of the stator case 2 and a rectangular length slightly larger than the length in the longitudinal direction to which the yoke main body 60 can be fixed and the outer width of the opposing pieces 60a, 60a. A recess 10d having a predetermined depth at
A conveyed article is fixedly formed in the through hole 10c and is provided with a ridge 10b which is vertically provided, and is formed. The guide plate 8 and the base plate 10 may be made of a non-magnetic metal material such as aluminum, for example, in addition to the above-mentioned synthetic resin material.

According to the brushless DC linear motor described above, at least two armatures 5 are integrally formed, so that it is not necessary to position each armature and fix it to the base 10, so that a simple configuration is obtained. Therefore, assembly becomes easier.

[0037]

In the brushless DC linear motor according to the first aspect of the present invention, the portion where the standing piece faces the permanent magnet has a wider width in the moving direction of the mover block than the portion where the coil is wound. Then, the gap between the adjacent yoke becomes small and the rate of change of the magnetic flux applied from the permanent magnet decreases, so that the force acting from the permanent magnet on the standing piece and the end of the yoke is reduced. The fluctuation becomes small, and the cogging force at the stop position or the traveling position becomes small.

The brushless DC linear motor according to the second aspect has the same effects as those of the first aspect, and can be mounted on an upright piece of another member after the coil is formed. After that, you can attach it to the standing piece,
It is easy to assemble.

Further, the brushless DC linear motor according to the third aspect has the advantages of the first and second aspects.
Since at least two armatures are integrally formed and there is no need to position and fix each armature to the base, the armature has a simple configuration, so that it is easier to assemble.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view showing a first embodiment of the present invention.

FIG. 2 is a perspective view of a permanent magnet of the DC brushless linear motor shown in FIG.

FIG. 3 is an exploded perspective view of an armature of the DC brushless linear motor shown in FIG.

FIG. 4 is an exploded perspective view of the DC brushless linear motor shown in FIG.

FIG. 5 is a wiring diagram of coils of the DC brushless linear motor shown in FIG.

FIG. 6 is a schematic configuration diagram of a controller that drives the DC brushless linear motor shown in FIG.

FIG. 7 is an explanatory diagram of a positional relationship between an armature and a permanent magnet of the DC brushless linear motor shown in FIG.

FIG. 8 is an exploded perspective view of an armature, which is a main part of the second embodiment of the present invention.

FIG. 9 is a sectional view of a conventional example.

FIG. 10 is an exploded perspective view of another conventional example.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 stator block 2 stator case 3 permanent magnet 4 mover block 5 armature 6 yoke 60 yoke main body 60 a opposing piece 61 standing piece 7 coil 9 magnetic sensor (position sensor)

Claims (3)

[Claims] An elongated stator case having a substantially U-shaped cross section and magnetized so that different poles are present in the thickness direction and different poles are present alternately at regular intervals in the longitudinal direction. A stator block having two plate-shaped permanent magnets disposed so that the same poles face each other at a predetermined interval; and a vertically opposed opposed piece in the middle of the substantially U-shaped opposed piece. An armature having a yoke having a set piece and a coil wound on the standing piece, and detecting a relative position in a longitudinal direction between the armature and the permanent magnet to control a direction of energizing the coil. And a mover block having a facing surface of the facing piece and the standing piece and a sensing surface of the position sensor facing a side surface of the permanent magnet. In the motor, the standing piece faces the permanent magnet. Brushless DC linear motor, characterized in that it has formed with a wider width toward the moving direction of the slider blocks than the portion that is wound in the coil portion. 2. The brushless DC linear motor according to claim 1, wherein the standing piece is a separate member fixed to a yoke main body forming the opposing piece. 3. The armature according to claim 1, wherein at least two of the armatures are integrally formed.
The brushless DC linear motor as described.