JP2008148491A - Motor and motor armature - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an armature which can be surely and smoothly started in rotation, even when the armature consists of one coil. <P>SOLUTION: A motor includes a flat plate-like magnet magnetized at a plurality of poles at a substantially equal angle, and an armature rotatably and pivotably supported facing the magnet and having a coil. A magnetic material is provided to the armature, and even when the magnetic material is positioned either at the boundary of each magnetized area of the magnet or at the center of each magnetized area of the magnet, the magnetic material is disposed at a position where the coil can be started. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a flat motor, and more particularly, to an armature structure including one coil.

  As a flat motor used for a cellular phone or the like, for example, a flat coreless vibration motor disclosed in Japanese Patent Laid-Open No. 6-205565 is known. A flat coreless vibration motor disclosed in Japanese Patent Laid-Open No. 6-205565 includes a flat circular magnet fixed to the bottom of a casing, a rotatable armature disposed so as to face the magnet, And a shaft arranged in the center of the child. The armature has three coils arranged in a fan shape and is integrally formed with the resin frame. The armature includes a commutator that rotates together with each coil. When the commutator comes into contact with two electrode brushes extending from the lower portion of the casing, the polarities of the three coils are alternately switched. Since an attractive force and a repulsive force are generated between the armature and the armature, the armature rotates. In particular, when used as a vibration motor, the armature itself is greatly decentered as described above, so that the armature rotates with a large centrifugal force, so that strong vibration is generated in the vibration motor.

Moreover, as a flat motor including one coil in an armature, for example, a flat motor disclosed in Japanese Patent No. 3039857 is known. In the flat motor disclosed in Japanese Patent No. 3039857, the armature is provided with a magnetic body, and when the armature stops rotating, the magnetic body is positioned at the boundary between the north and south poles of the magnet, and the coil is activated. It tries to come to a possible position.
JP-A-6-205565 Japanese Patent No. 3039857

  In the above-described flat motor including one coil in the armature, the armature is provided with a magnetic body, and the magnetic body is positioned at the boundary between the N pole and the S pole of the magnet when the rotation of the armature is stopped. However, even if the magnetic body is positioned at the boundary between the north and south poles of the magnet when the armature stops rotating, if the positional relationship between the coil and the magnetic body is not properly determined, the coil can be activated. May not stop.

  Furthermore, the magnetic body provided in the armature may stop at the center of each pole in addition to the boundary between the N pole and S pole of the magnet. In this state, since the coil stops at a point where the magnetic force generated by the magnet is weak (a point where the magnetic flux density is low), the armature may not start.

  In order to specifically explain this problem, as an example, the angle between the coil of the armature and the magnetic body (the point where the current flows in the longitudinal direction of the armature (points A and B) is close to the magnetic body. Let us consider a case where the angle between the point and the center of the magnetic body is 45 degrees.

  As shown in FIG. 7, when the magnetic body 10 provided in the armature 4 stops at the boundary between the north pole and the south pole of the magnet 3, the point A and the point B of the coil 6 are the center part of the magnet 3 (that is, , Located at a point where the magnetic flux density is large. Therefore, when a current flows through the coil 6, a strong electromagnetic force is applied to the coil 6 and the armature rotates.

  On the other hand, as shown in FIG. 8, when the magnetic body 10 provided in the armature 4 stops at the center of the north pole of the magnet 3, the points A and B of the coil 6 are the boundaries of the magnet 3 (that is, the magnetic flux density). It is located at a point with less. Therefore, when a current flows through the coil 6, the electromagnetic force applied to the coil 6 is weak, the torque at which the armature 4 starts to rotate is insufficient, and the motor may not start.

  The magnet is usually arranged on the commutator side of the armature, but in FIGS. 7 and 8, it is shown on the rear side of the armature for the sake of explanation.

  Therefore, an object of the present invention is to provide a highly reliable motor by an armature that is reliably and smoothly started even when an armature is constituted by a single coil.

  A first invention is a motor comprising: a plate-like magnet magnetized with a plurality of poles at substantially equal angles; and an armature that is rotatably supported so as to face the magnet and has a coil. The armature is provided with a magnetic body, and the coil can be activated even when the magnetic body is located at either the boundary of the magnetized regions of the magnet or the center of the magnetized regions of the magnet. The magnetic body was disposed.

  According to a second aspect of the present invention, in the first aspect, the end of the coil may be located at any of the boundary between the magnetized regions of the magnet and the center of the magnetized regions of the magnet. The motor according to claim 1, wherein the motor is disposed at a position away from a boundary of each magnetized region by a predetermined distance.

  According to a third invention, in the first or second invention, a central angle of the coil is substantially equal to a central angle of each of the magnetized regions, and the magnetic body has a central angle of each of the magnetized regions as θ. In this case, the coil is disposed at a position where the central angle satisfies (2n + 1) × 0.25 × θ (n is an integer) from one end of the coil.

  According to a fourth invention, in the first to third inventions, a central angle of the coil is substantially equal to a central angle of each of the magnetized regions, and the magnetic body extends from one end of the coil to each of the magnetized regions. It arrange | positions in at least one position of 0.25 times and 0.75 times of a central angle.

  According to a fifth invention, in the first to fourth inventions, the magnet is magnetized into four poles, and the magnetic body has center angles of 22.5 degrees and 67.5 degrees from one end of the coil. It arrange | positions in at least one position.

  A sixth invention is an armature that is rotatably supported opposite to a magnet in a motor having a magnet including a plane magnetized with a plurality of poles at substantially equal angles, the coil and the magnet The magnetic body is disposed at a position where the coil can be activated regardless of whether the magnetic body is located at the boundary between the magnetized regions of the magnet or at the center of the magnetized region of the magnet. .

  According to the present invention, the coil stops at the position where the coil can be activated regardless of whether the magnetic body is located at the boundary between the magnetized regions of the magnet or the center of the magnetized region of the magnet. The resulting winding part stops in the magnet. That is, since the winding portion that generates the rotational force of the coil does not stop at the boundary of each magnetized region, an electromagnetic force sufficient for starting the armature can be obtained, and the rotation of the armature can be started smoothly. .

  In addition, even when the armature is composed of a single coil, the rotation of the armature can be started reliably and smoothly, and the flat motor can be further minimized and reduced in weight, further reducing the manufacturing cost. can do.

  Hereinafter, the structure of the flat motor according to the present invention will be described with reference to the drawings.

  FIG. 1 is a longitudinal sectional view showing an example of a flat motor according to an embodiment of the present invention.

  The flat motor 1 of the present embodiment is housed in a space formed by the upper casing 2A and the lower casing 2B. A flat magnet 3 is fixed to the inside of the lower casing 2B. The magnet 3 is formed in a substantially disk shape (more precisely, a donut-shaped plate shape with a missing central portion), and is magnetized by being divided into a plurality of poles. Therefore, one magnet including the N pole and the S pole is formed by one magnetized region that is divided and magnetized. In the present embodiment, a four-pole magnetized magnet is shown in which a disc is divided into four equal parts and N poles and S poles are alternately arranged, but other numbers of poles (for example, 6 poles, 8 poles, etc.) You may use the magnet magnetized by.

  Bearings 12 and 13 are provided at the center of the upper casing 2A and the center of the lower casing 2B, respectively. A shaft 5 is rotatably attached to the bearings 12 and 13. An armature 4 composed of a resin frame 7 is attached to the shaft 5. Therefore, the armature 4 is rotatably attached to the casings 2A and 2B via the bearings 12 and 13.

  In FIG. 1, the shaft 5 is illustrated so as to penetrate the bearings 12 and 13. However, the shaft 5 may not penetrate the bearings 12 and 13 and the end portion of the shaft 5 may not be exposed. . Further, the bearings 12 and 13 are provided in the casings 2A and 2B, and the shaft 5 is rotatably provided to the casings 2A and 2B. The shaft 5 is fixed to the casings 2A and 2B, and the armature 4 is provided with a bearing. Thus, the armature 4 may be structured to be rotatable with respect to the shaft 5 (so-called fixed shaft structure).

  The resin frame 7 of the armature 4 is integrally formed with a coil 6 having a substantially trapezoidal shape (a sector having a missing central portion).

  The armature 4 includes a commutator 8 connected to the coil 6. The lower casing 2B is provided with two brushes 9 extending inward. One end of the brush 9 is connected to a power supply terminal (not shown) through which DC power is supplied to the flat motor. The other end (contact portion) of the brush 9 is in contact with the commutator 8. A current is supplied to the coil 6 by the contact between the commutator 8 and the brush 9. When the armature 4 rotates, the contact point between the commutator 8 and the brush 9 moves, and the polarity of the coil 6 is switched. Every time the polarity of the coil 6 is switched, an attracting force and a repulsive force are generated between the coil 6 and the magnet 3, so that the armature 4 continues to rotate.

  FIG. 2 is a rear view (viewed from the direction of the commutator 8) showing the configuration of the armature 4 according to the embodiment of the present invention.

  As described above, the armature 4 is constituted by the resin frame 7 in which the substantially trapezoidal coil 6 is integrally formed. Further, a commutator 8 divided into four poles around the shaft 5 is provided on the back side of the resin frame 7. In other words, the armature 4 is formed by disposing one substantially quarter circular coreless coil 6 and a magnetic body 10 inside a resin frame 7 and integrally molding them into a fan shape. In addition, as shown in FIG. 2, the center angle of the sector which forms the armature 4 may exceed 180 degree | times.

  The coil 6 is a single coreless coil having a shape substantially corresponding to the shape of the resin frame 7, and an opening angle θ of both side edges (portions where current flows in the diameter direction of the coil winding) is about 90 degrees. When the flat motor 1 is used as a vibration motor, a weight may be disposed in the air core of the coil 6 in order to increase the centrifugal force.

  The crimped portion of the resin frame 7 is provided with a commutator 8 having four electrodes obtained by dividing a circle into four equal parts. A shaft hole is formed at the center of the commutator 8 (position equal to the rotation center of the armature 4), and the shaft 5 is inserted into the shaft hole. The commutator 8 is connected to two electrodes facing each other in the diagonal direction, one end of which is connected to the inner end of the coreless coil 6, and the other electrode is connected to the outer end. ing.

  In the present embodiment, the armature 4 includes a substantially quarter circular coil 6 having an angle of about 90 degrees, but the shape of the coil is not limited to this. The fact that the coil 6 has a substantially quarter circle corresponds to the magnet 3 being divided into four poles and magnetized. That is, the central angle of the coil is substantially the same as the central angle of one magnetized region where the magnet 3 is divided and magnetized. Therefore, when the magnet 3 is magnetized to four poles as in the present embodiment, the coil 6 is formed with a central angle of about 90 degrees. Further, for example, when the magnet 3 is divided into 6 poles and magnetized, the coil is preferably formed in a substantially 1/6 circle having an angle of about 60 degrees. The commutator 8 also has its electrodes divided according to the center angle of the coil 6.

  Further, the magnetic body 10 disposed on the resin frame 7 of the armature 4 can be formed of a thin round bar made of iron, and is disposed substantially parallel to the rotation direction (or reverse rotation direction) of the armature 4. . In addition, the magnetic body 10 is not limited to a thin round bar, and may be a flat piece or a square bar having a rectangular cross section. By forming the magnetic body 10 long along the rotation direction, the N pole and the S pole are easily formed on both sides of the magnetic body 10. In the present invention, when the armature 4 stops, the magnetic body 10 needs a magnetic force for forcibly stopping the armature at a predetermined position. Furthermore, it is necessary to have a magnetic force that does not hinder the rotational movement of the armature 4.

  The center of the magnetic body 10 is disposed at a central angle of about 67.5 degrees from one end (point A) of the coil 6. As will be described later, this position corresponds to 3/4 of the central angle (90 degrees) of one magnetized region of the magnet.

  Although the magnetic body 10 is disposed substantially parallel to the rotation direction, the magnetic body 10 may not necessarily be orthogonal as long as the N pole and the S pole can be generated on both sides of the magnetic body 10.

  In addition, as shown in FIG. 5, the magnetic body 10 may be disposed at a center angle of about 22.5 degrees from the one end (point A) of the coil 6. As will be described later, this position corresponds to a quarter of the central angle (90 degrees) of one magnetized region of the magnet.

  In addition, as shown in FIG. 6, the magnetic body 10 may be provided in the air core portion of the coil 6. In this case, the center of the magnetic body 10 is at a center angle of about 67.5 degrees from one end (point A) of the coil 6 and at a center angle of about 22.5 degrees from the other end (point B) of the coil 6. Has been placed. As will be described later, this position corresponds to 3/4 of the central angle (90 degrees) of one magnetized region of the magnet 3 (1/4 from the point B).

That is, in the armature 4 of the flat motor to which the present invention is applied, the magnetic body has a central angle of one magnetized region of the magnet 3 from one end of the coil as θ,
(2n + 1) × 0.25 × θ (n is an integer)
It suffices if it is in a position that satisfies

  Further, as shown by a broken line in FIG. 6, as an application of the armature 4, two armatures are provided in the armature 4, and the center of one magnetic body 10 is approximately 22.2 from one end (point A) of the coil 6. The center angle of the other magnetic body 11 is about 22.5 degrees from the other end (point B) of the coil 6 (about 67.5 degrees from the point A) with a central angle of 5 degrees (approximately 67.5 degrees from the point B). It can also be arranged at the center angle position. As will be described later, this position corresponds to a quarter of the central angle (90 degrees) of one magnetized region of the magnet.

  Furthermore, the armature 4 may be configured to include a plurality of magnetic bodies arranged as shown in FIGS. 2, 5, and 6. For example, the first magnetic body 10 is provided at a position of 67.5 degrees outward from the point A of the coil 6 as shown in FIG. 2, and 22.5 degrees inward from the point A of the coil 6 as shown in FIG. The second magnetic body 11 may be provided at this position. The combination of the number of magnetic bodies and the positions of the magnetic bodies can be arbitrarily selected as long as the above-described conditions for the arrangement positions of the magnetic bodies are satisfied.

  As shown in FIG. 1 of FIG. 1 of Japanese Patent No. 3039857, which is a known technique, the magnetic body 10 is not embedded and integrally molded in the resin frame 7 as shown in FIG. You may protrude in the side (rotation direction) from one side edge. In this case, the magnetic body 10 may be slightly curved inward so as to constitute a part of the arc.

  Next, the rotation principle of the flat motor 1 according to the embodiment of the present invention will be described.

  As shown in FIG. 1, two brushes 9 extend from the lower casing 2 </ b> B, and a contact portion provided at the tip of the brush 9 contacts each electrode of the commutator 8 of the armature 4. Each brush 9 sequentially moves at the contact point with the commutator 8 while sliding on the commutator 8 at a predetermined angle (for example, about 90 degrees) as the armature 4 rotates. To go.

  FIG. 3 shows a state when the armature 4 is stopped. In the state shown in FIG. 3, most of the coil 6 overlaps with one S pole of the magnet 3, and a part overlaps with one N pole of the magnet 3. When power is supplied to the flat motor 1 in this state, a current flows through the coil 6 through the electrode of the commutator 8 with which the tip of the brush 9 contacts, thereby generating a magnetic field in the coil 6. If the polarity of the magnetic field generated on the side of the coil 6 facing the magnet 3 (front side in the drawing) is the S pole, a repulsive force is generated between the S pole of the magnet 3 in the vicinity thereof. Further, since the N poles adjacent to the magnet 3 attract each other, a rotational force is generated in that direction (counterclockwise direction), and the armature 4 starts to rotate. The magnet 3 is originally disposed on the back surface side (commutator 8 side) of the armature 4, but in FIG. 3 and FIG. 4, it is illustrated on the rear side of the armature for explanation.

  When the armature 4 is further rotated, the electrode adjacent to the commutator 8 contacts the contact portion of the brush 9, so that a current in the direction opposite to that shown in FIG. For this reason, a reverse polarity (N pole) is generated in the coil 6 on the side facing the magnet 3, repels the N pole on the lower side of the magnet 3, and a rotating force in the same direction is applied to keep rotating.

  Thus, according to the rotation of the armature 4, the coil 6 alternately repeats the N pole and the S pole, and repeats repulsion and attraction with the magnet 3. As a result, the armature 4 can continue to rotate.

  When the armature 4 is rotated in the reverse direction (clockwise direction), the current supply direction is reversed or the winding direction of the coil 6 is reversed.

  3 and 4 are explanatory diagrams at the time of start-up showing the rotation principle of the armature 4 of the embodiment shown in FIG. 2 of the present invention, and FIG. 3 shows that the magnetic body 10 provided in the armature 4 is a magnet. FIG. 4 shows a state where the magnetic body 10 provided in the armature 4 is stopped at the center of the N pole of the magnet 3.

  In the armature 4 of the present embodiment having the structure described above, after the armature 4 is rotated clockwise (or counterclockwise) on the magnet 3, the power supplied to the coil 6 of the armature 4 is supplied. 3, the center of the magnetic body 10 in the longitudinal direction is stopped on the boundary line 21 between the N pole and the S pole of the magnet 3 as shown in FIG. This is because when the magnetic body 10 is positioned on the boundary line 21 between the N pole and the S pole of the magnet 3, one end in the longitudinal direction of the magnetic body 10 is magnetized to the S pole by the influence of the magnet 3, and the other end is the N pole. This is because the magnet 3 and the magnetic body 10 are attracted to each other and overcome the free rotation of the armature 4 to be in a stable state where it stops at that position.

  At this time, when the magnetic body 10 provided in the armature 4 stops at the boundary between the N pole and the S pole of the magnet 3, the points A and B of the coil 6 are the center of the N pole of the magnet 3 or the S pole. It is located at a point about 22.5 degrees away from the center. Therefore, when a current flows through the coil 6, an electromagnetic force sufficient for starting the armature 4 is applied to the coil 6 and the armature 4 rotates.

  Further, the armature 4 of the present embodiment, when the armature 4 is rotated clockwise (or counterclockwise) on the magnet 3 and then the power supplied to the coil 6 of the armature 4 is cut off, As shown in FIG. 4, the magnetic body 10 stops even when the center in the longitudinal direction is located at the center of the south pole (or north pole) of the magnet 3. This is because the magnetic part 10 is attracted to the center of the S pole (or S pole) of the magnet 3 because the magnetic flux density is large in the center part of the N pole (or S pole) of the magnet 3. It is because it will be in a stable state where it overcomes the free rotation and stops at that position.

  At this time, when the magnetic body 10 provided in the armature 4 stops at the center of the S pole of the magnet 3 (the same applies when it stops at the center of the N pole), the points A and B of the coil 6 are It is located at a point about 22.5 degrees away from the center of the north pole or the center of the south pole. Therefore, when a current flows through the coil 6, an electromagnetic force sufficient for starting the armature 4 is applied to the coil 6 and the armature 4 rotates.

  That is, the flat motor 1 according to the present embodiment is about 22.5 degrees away from the center of the S pole or the center of the N pole of the magnet 3 regardless of the position of the armature 4 due to the action of the magnetic body 10. The winding portion (point A and point B) that generates the rotational force of the coil 6 stops at the point. As can be seen from the above description, the position 22.5 degrees apart is the midpoint of the boundary between the center of the south pole (or north pole) of the magnet 3 and the south pole and north pole.

  In addition, 22.5 degree | times shown by this embodiment are equivalent to 1/4 of the center angle (90 degree | times) of one magnetization area | region of the magnet 3, and 67.5 degree | times is one magnetization area | region of the magnet 3. Is equivalent to 3/4 of the central angle (90 degrees). That is, 22.5 degrees is half the angle formed by the center of one magnetized region of the magnet 3 and the boundary between adjacent magnetized regions. If the magnetic body 10 is arranged at the half angle position, the magnetic body 10 stops at the boundary between the N pole and the S pole of the magnet 3, and the magnetic body 10 has the N pole (or S pole) of the magnet 3. ) And the case where the armature 4 is stopped at the center, an even electromagnetic force can be obtained and the armature 4 can be smoothly started.

  Note that 22.5 degrees and 67.5 degrees are the optimum angle values proposed by the present invention, but even if this angle is slightly deviated (for example, several degrees), the armature 4 is in two stopped states. The electromagnetic force at the time of starting becomes unbalanced, but it does not matter as long as it does not have a great influence on the starting of the armature 4. For example, when the magnetic body 10 stops at the boundary between the N pole and the S pole of the magnet 3, the point A of the coil 6 is set to 15 degrees from the center of the N pole (or S pole) of the magnet. When the magnetic body 10 stops at the center of the N pole (or S pole) of the magnet 3, the point A of the coil 6 is separated by 30 degrees from the center of the N pole (or S pole) of the magnet. Even in this case, the start-up of the armature 4 is not greatly affected.

  Therefore, in any case, the flat motor 1 of the present embodiment is sufficient for starting the armature 4 because the points A and B of the coil 6 are not located at the boundary between the S pole and the N pole of the magnet 3. Electromagnetic force can be obtained, and the rotation of the armature 4 can be started smoothly.

  Similarly, at a position corresponding to 5/4 and 7/4 of the central angle of one magnetized region of the magnet 3, at a point about 22.5 degrees away from the center of the S pole or the center of the N pole of the magnet 3. Since the winding portions (points A and B) that generate the rotational force of the coil 6 are stopped, an electromagnetic force sufficient for starting the armature 4 can be obtained.

  In other words, in the flat motor 1 of the present embodiment, the armature is such that the coil 6 is necessarily located at the midpoint between the center of the S pole (or N pole) of the magnet 3 and the boundary between the S pole and the N pole. 4 is stopped (the points A and B are not stopped at the boundaries between the magnetized regions of the magnet 3). This is the essence of the present invention.

  Similarly, the armature 4 according to the embodiment shown in FIG. 5 and the armature 4 according to the embodiment shown in FIG. 6 are arranged even when the magnetic body 10 stops at the boundary between the N pole and the S pole of the magnet 3. Even when the magnetic body 10 stops at the center of the N pole (or S pole) of the magnet 3, the rotational force of the coil 6 is about 22.5 degrees away from the center of the S pole or the center of the N pole of the magnet 3. The winding part (point A and point B) that generates the point stops. Therefore, the flat motor 1 according to the embodiment shown in FIG. 5 also does not stop at the boundary between the S pole and the N pole of the magnet 3 at the points A and B of the coil 6. A force can be obtained, and the rotation of the armature 4 can be started smoothly.

  The flat motor using the magnet divided and magnetized into four poles has been described above, but the present invention can also be applied to a flat motor using a magnet magnetized into six poles. That is, in the magnet magnetized with 6 poles, the central angle of one magnetized region is 60 degrees. At this time, in order to obtain an electromagnetic force sufficient for starting the armature 4 at any stop position, the center of the S pole (or N pole) of the magnet 3 and the middle of the boundary between the S pole and N pole. In order to stop the points A and B of the coil 6, the center of the magnetic body 10 is moved from one end (point A) of the coil 6 to 1 / of the central angle (60 degrees) of one magnetized region of the magnet. It may be arranged at a position of approximately 15 degrees corresponding to 4, a position of approximately 45 degrees corresponding to 3/4, and a position of an angle corresponding to (2n + 1) / 4. Note that n is an integer.

  Similarly, when the present invention is applied to a flat motor using a magnet magnetized in eight poles, the center of the magnetic body 10 is centered from one end (point A) of the coil 6 in one magnetized region of the magnet. Arranged at a position of approximately 11.25 degrees corresponding to 1/4 of the angle (45 degrees), a position of approximately 33.75 degrees corresponding to 3/4, and a position of an angle corresponding to (2n + 1) / 4 do it. Note that n is an integer.

  As described above, the present invention is not limited to a flat motor using magnets magnetized to four poles, but also to flat motors using magnets magnetized to other pole numbers (for example, six poles, eight poles, etc.). It can also be applied to motors.

It is a longitudinal section showing an example of a flat motor of an embodiment of the invention. It is a reverse view which shows the structure of the armature of embodiment of this invention. It is explanatory drawing at the time of the start which shows the rotation principle of the armature of embodiment of this invention. It is explanatory drawing at the time of the start which shows the rotation principle of the armature of embodiment of this invention. It is a reverse view which shows another structure of the armature of embodiment of this invention. It is a reverse view which shows another structure of the armature of embodiment of this invention. It is explanatory drawing which shows the problem at the time of the starting of the conventional armature. It is explanatory drawing which shows the problem at the time of the starting of the conventional armature.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Flat motor 2A Upper casing 2B Lower casing 3 Magnet 4 Armature 5 Shaft 6 Coreless coil 7 Resin frame 8 Commutator 9 Brush 10, 11 Magnetic body 12, 13 Bearing

Claims (6)

A motor comprising: a plate-like magnet magnetized in a plurality of poles at substantially equal angles; and an armature that is rotatably supported opposite to the magnet and has a coil,
A magnetic body is provided in the armature,
The magnetic body is arranged at a position where the coil can be activated regardless of whether the magnetic body is located at the boundary between the magnetized regions of the magnet or at the center of the magnetized region of the magnet. Motor.   The end of the coil is separated from the boundary of each magnetized region by a predetermined distance regardless of whether the magnetic body is located at the boundary between the magnetized regions of the magnet or the center of each magnetized region of the magnet. The motor according to claim 1, wherein the motor is disposed at a different position. The central angle of the coil is substantially equal to the central angle of each magnetized region,
The magnetic body is disposed at a position where the central angle satisfies (2n + 1) × 0.25 × θ (n is an integer) from one end of the coil, where θ is the central angle of each magnetized region. The motor according to claim 1 or 2. The central angle of the coil is substantially equal to the central angle of each magnetized region,
The said magnetic body is arrange | positioned in the at least one position of 0.25 times and 0.75 times the central angle of each said magnetization area | region from the end of the said coil. The motor as described in one. The magnet is magnetized to 4 poles,
5. The magnetic body according to claim 1, wherein the magnetic body is disposed at at least one of a central angle of 22.5 degrees and 67.5 degrees from one end of the coil. motor. In a motor having a magnet including a plane magnetized with a plurality of poles at substantially equal angles, the armature is pivotally supported so as to face the magnet,
A coil and a magnetic body;
The magnetic body is arranged at a position where the coil can be activated regardless of whether the magnetic body is located at the boundary between the magnetized regions of the magnet or at the center of the magnetized region of the magnet. Armature for motor.