JPH1052026A - Brushless dc linear motor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a large thrust with narrow rails by arranging erected pieces, counter pieces, and a position sensor so that the side faces of the erected and counter counter pieces and the detecting surface of the sensor can be faced oppositely to the side faces of permanent magnets. SOLUTION: When the relative positions between permanent magnets 3 and 3 and an armature 5 are set so as to make stronger the magnetic attraction which varies depending upon the intensities of magnetic poles generated at the end faces of erected pieces 6b and 6b and counter pieces 6c and 6c and the magnitude of the magnetic field generated by the magnets 3 and 3 in addition to the energizing current of a coil 7, the interval between the counter side faces of the pieces 6b and 6c and the side faces of the magnets 3 can be made as shorter as possible and a large thrust can be obtained with narrow rails. In addition, since a yoke 6 is formed by bringing one external surfaces of the U-shaped constituent pieces of the erected pieces 6 and 6 with each other, the yoke 6 having a complicated shape can be formed at a low cost by combining parts having simple shapes with each other.

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. 7, 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-mentioned motor, the driving force of the linear motor is based on the electromagnetic force, and the magnetic flux density B (Wb /
Square m), the number of turns N of the coil, and the current value I to be energized
(A), assuming that the area A (square m) of the hollow portion facing the flat coil 7 is, the thrust F is given by: F = BIAAN (N / m). Therefore, in order to increase the thrust F, it is conceivable to increase the size of the permanent magnets 3, 3, increase the current flowing through the flat coil 7, or increase the number of turns. As a result, in order to obtain a large thrust, the thickness dimension of each coil unit 4 was large, and the rail 2 was large in width.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a small brushless DC linear motor capable of obtaining a large thrust with a rail having a small width.

[0007]

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. It is set to be equipped with and. Thereby, a long stator case having a substantially U-shaped cross section,
It is magnetized so that different poles are present in the thickness direction and different poles are alternately present at regular intervals in the longitudinal direction, and is arranged in a stator case so that the same poles face each other with a predetermined interval in the stator case. An electric machine having a stator block having two permanent magnets, a yoke having a standing piece facing the facing piece in the middle of a substantially U-shaped facing piece, and a coil wound around the standing piece Armature, and a position sensor for detecting the relative position in the longitudinal direction of the armature and the permanent magnet to control the direction of current supply to the coil, and the opposing side surfaces of the opposing piece and the standing piece having A mover block disposed so that a detection surface of the position sensor faces a side surface of the permanent magnet.

According to a second aspect of the present invention, there is provided a brushless DC linear motor, wherein the standing piece according to the first aspect is formed by abutting the outer surfaces of one opposed piece of the substantially U-shaped piece. As a result, the yoke is formed by abutting the standing piece on the outer surface of one of the opposed pieces of the substantially U-shaped element.

According to a third aspect of the present invention, there is provided a brushless DC linear motor, wherein an end of the opposing piece of the yoke according to the first or second aspect is formed so as to approach the standing piece. Thereby, the end of the opposing piece of the yoke is formed so as to approach the standing piece.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a DC brushless linear motor according to the present invention will be described below with reference to FIGS. FIG. 1 is a sectional view of a linear motor. FIG.
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 the DC brushless linear motor shown in FIG. FIG. 4 is a wiring diagram of coils of the DC brushless linear motor shown in FIG. FIG. 5 is a schematic configuration diagram of a controller that drives the DC brushless linear motor shown in FIG. FIG. 6 is an explanatory diagram of a positional relationship between an armature and a 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 predetermined intervals 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 and 3 are magnetized so that different poles are present in the thickness direction and the different poles are alternately present 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. The movable block 4 is used in such a manner that a number of units required as a transport thrust, such as a door to be transported, are connected in a longitudinal direction at predetermined intervals, and in the present embodiment, three movable units are used. The child blocks 4 are provided continuously.

The armature 5 has a yoke 6 and a coil 7 wound around standing pieces 6b, 6b of the yoke 6, which will be described later. The yoke 6 is made of a magnetic metal material and is formed by, for example, cutting so that one end 6d of the substantially U-shaped opposing piece 6c approaches the side of the other opposing piece. The pieces 6a, 6a are combined and formed. And
In the middle of the substantially U-shaped opposed pieces 6c, 6c, a shape having standing pieces 6b, 6b opposed to these opposed pieces is formed.

The coil 7 has a winding body 7b of a bobbin 7a formed of a synthetic resin or the like, and a soft copper wire whose surface is covered with an insulating layer, for example, is wound at the U-shaped opening side of the yoke 6, that is, at the upper end. It is formed by winding as a side. As shown in the wiring diagram of FIG. 4, the start end and the end of the winding end of the coil 7 are 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 substantially U-shaped piece 6a of the yoke 6 in the longitudinal direction and the outer shape of the wound coil 7 are equal to the pitch between the same poles of the permanent magnet 3 in the longitudinal direction. It is appropriately set to a value smaller than 1/3 of the dimension L.
Then, the substantially U-shaped element pieces 6a, 6a abut the standing pieces 6b, 6b formed by contacting the opposing outer surfaces corresponding to the other of the above-mentioned pieces, and the bobbin 7b of the bobbin 7a of the coil 7
Are inserted and fitted together. The armature 5 has ends 6 d, 6 d of the opposed pieces of the yoke 6 depending on the direction of the current flowing through the coil 7.
When one of the magnetic poles is an N pole, the other is also an N pole, and one is an S pole.
When it is a pole, the other also forms an S pole. The substantially U-shaped element 6a 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 guide plates 8 and 8 are for positioning the yoke 6 together with a base 10 to be described later. The guide plates 8 are made of a non-magnetic 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 has a longitudinal edge side and the recess 8a.
A fixing portion 8c for fixing a magnetic sensor 9 described later at the same interval P as the predetermined interval P is provided in the middle of each.

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 of energization of the coil 7, and in this embodiment, 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 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, and the detection signal is arithmetically processed by the control unit 11c. 5 are detected.

The base plate 10 positions and arranges 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 slightly 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
A substantially U-shaped piece 6a of the yoke 6 for fixing the armature 5
, And a rectangle having a predetermined depth, which is slightly larger than the outer pitch dimension of the substantially U-shaped outer facing piece 6c formed by combining the width in the longitudinal direction and the substantially U-shaped element pieces 6a, 6a. 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.

The armature 5 includes a bobbin 7a and a standing piece 6b, which is formed by combining two substantially U-shaped pieces 6a, 6a as described above and abutting the outer surfaces of the opposing pieces.
Are fitted and fixed in the recess 10a of the base 10, and three are arranged at a predetermined interval P. The U-shaped outer end 6d is similarly positioned at a predetermined interval P by the recess 8a of the guide plate 8 to form one unit of the mover block 4. 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.
By this control device 11, two of the three armature coils a1 to a3, b1 to b3, and c1 to c3 of the armature coil 7 of each of the three units of the mover block 4 of the brushless DC linear motor are provided. 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, the substantially U-shaped pieces 6a and 6
Excitation current for exciting a 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 standing pieces 6b, 6b have S poles, and the opposing pieces 6d, 6d have N poles. When a current is applied in the counterclockwise direction, that is, in the counterclockwise direction, the standing pieces 6b, 6b around which the coil 7 facing the side surface of the permanent magnet 3 is wound have N poles,
d and 6d are S poles, respectively.

When the armature 5 of the mover block 4 and the permanent magnets 3 of the stator block 1 are in the positions shown in FIG. And the yoke 6 of the armature 5 having the signs of a and c.
The polarities of the surfaces of the standing pieces 6b, 6b facing the permanent magnet 7 are set as shown in FIG. Therefore, a
And the permanent magnets 3 and 3 having the coil 7 with the reference numerals c and c generate a repulsive force between opposing magnetic poles and an attractive force between adjacent magnetic poles. A thrust to the right in the figure works.

Next, when the mover block 4 moves rightward by the above-mentioned propulsive force and moves to the position shown in FIG. 6B, 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
The polarity of the surfaces of the standing pieces 6b and 6b of the yoke 6 of the armature 5 of the reference numerals c and c facing the permanent magnet 7 is set to the state shown in FIG. Therefore, in the same manner as described above, the armature 5 having the coils 7 of b and c and the permanent magnets 3 and 3 have a repulsive force between opposing magnetic poles and a repulsive force between adjacent magnetic poles. Generates an attractive force, and a propulsive force acts on the permanent magnets 3 and 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, 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, (a) in 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 this propulsion is
Of the magnetic poles generated on the end faces of the standing pieces 6b, 6b and the opposing pieces 6c, 6c, and the magnitude of the magnetic field generated by the permanent magnets 3, 3 by the current flowing through the yoke 6, that is, the exciting current for magnetizing the yoke 6. It changes with the suction (repulsion) force. Therefore, to increase this magnetic force,
The distance between the opposing side surfaces of the opposing piece 6b and the standing piece 6c and the side surface of the permanent magnet 3 is made as small as possible to set the relative position of the permanent magnet 3 and the armature 5 and the like. Also, the end of the opposing piece 6c of the substantially U-shaped element 6a is
It is formed so as to be close to b and reduce the magnetic resistance. In the case where the propulsion force is obtained in the left direction in the drawing, that is, in the reverse direction, the timing of the power supply switching by the control device 11 is changed to cope with the problem.

According to the brushless DC linear motor described above, a long stator case 2 having a substantially U-shaped cross section is provided.
Are arranged such that different poles exist in the thickness direction and different poles alternately exist at regular intervals in the longitudinal direction, and are arranged in the stator case 2 so that the same poles face each other at a predetermined interval. A stator block 1 having two plate-shaped permanent magnets 3, 3 and a standing piece 6b, 6b opposed to the opposed pieces 6c, 6c is provided between the substantially U-shaped opposed pieces 6c, 6c. An armature 5 having a yoke 6 and a coil 7 wound on the standing pieces 6b, 6b, and a longitudinal direction of the armature 5 and the permanent magnets 3, 3 for controlling a direction of current to the coil 7 And a magnetic sensor 9 for detecting a relative position of the permanent magnets 3 and 6, and the opposing side surfaces of the opposing pieces 6 c and 6 c and the standing pieces 6 b and 6 b and the detection surface of the position sensor are And a mover block 4 disposed opposite to the movable block.
The magnitude of the propulsion force is determined by the strength of the magnetic poles generated on the end faces of the standing pieces 6b, 6b and the opposing pieces 6c, 6c and the magnitude of the magnetic field generated by the permanent magnets 3, 3, in addition to the current flowing through the coil 7. In order to increase the attractive force (repulsion), the relative position between the permanent magnet 3 and the armature 5 is set so that the opposing side surfaces of the opposing piece 6b and the standing piece 6c and the side surface of the permanent magnet 3 are opposed. The spacing dimension can be made as small as possible, and a large thrust can be obtained with a rail having a small width.

The yoke 6 is provided with its standing pieces 6b, 6b
Is formed by abutting the outer surfaces of one of the substantially opposite U-shaped pieces 6a, 6a, so that a yoke 6 having a complicated shape is formed by a combination of parts having the same shape. Yes, it can be configured at low cost. Also, the ends 6d, 6d of the opposing pieces 6c, 6c of the yoke 6 are
b, 6b, the magnetic resistance of the substantially U-shaped element 6a is reduced,
It will have more propulsion.

[0028]

According to the first aspect of the present invention, there is provided a brushless DC linear motor having a long stator case having a substantially U-shaped cross section, and having different poles in the thickness direction and having different poles alternately at regular intervals in the longitudinal direction. A flat plate 2 which is magnetized so as to exist and is disposed on the stator case so that the same poles face each other at a predetermined interval.
An armature having a stator block having two permanent magnets, a yoke having a standing piece opposed to the facing piece in the middle of the substantially U-shaped facing piece, and a coil wound around the standing piece. And a position sensor for detecting the relative position of the armature and the permanent magnet in the longitudinal direction for controlling the direction of current supply to the coil, and having the opposing side surfaces of the opposing piece and the standing piece, Since the detection surface of the position sensor includes the mover block disposed to face the side surface of the permanent magnet, the magnetic attraction (repulsion) force between the stator block and the mover block is increased. And a large thrust can be obtained with a rail having a small width.

According to a second aspect of the present invention, in addition to the effects of the first aspect, the yoke is formed by connecting the standing piece to the outer surface of one of the substantially U-shaped opposed pieces. Is formed by abutting the parts, so that a yoke 6 having a complicated shape can be formed by combining parts having the same shape and a simple shape, and can be configured at low cost.

The brushless DC linear motor according to the third aspect has the effect of the first or second aspect.
Since the end of the opposing piece of the yoke is formed so as to approach the standing piece, the magnetic resistance of the substantially U-shaped piece is reduced, and the propulsion force is increased. Become.

[Brief description of the drawings]

FIG. 1 is a sectional view showing an embodiment of a DC brushless linear motor 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 the DC brushless linear motor shown in FIG.

FIG. 4 is a wiring diagram of coils of the DC brushless linear motor shown in FIG.

FIG. 5 is a schematic configuration diagram of a controller that drives the DC brushless linear motor shown in FIG.

FIG. 6 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. 7 is a sectional view of a conventional example.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Stator block 2 Stator case 3 Permanent magnet 4 Mover block 5 Armature 6 Yoke 6a Substantially U-shaped element 6b Standing piece 6c Opposing 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, wherein the opposing side surfaces of the opposing piece and the standing piece and the detection surface of the position sensor have a mover block disposed to face the side surface of the permanent magnet. Brushless DC linear motor. 2. The brushless DC linear motor according to claim 1, wherein the standing piece is formed by abutting the outer surfaces of one of the opposed pieces of the substantially U-shaped element piece. 3. The brushless DC linear motor according to claim 1, wherein an end of the opposing piece of the yoke is formed so as to approach the standing piece.