JP2006136087A - Dc machine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an inexpensive DC machine with a linear rectifying characteristic. <P>SOLUTION: A motor 1 is provided with two brushes 5a, 5b. The brushes 5a, 5b have double layer structures each comprising a high-resistance sections 12 with a high-resistance material and a low-resistance section 13 with a low-resistance material having resistance lower than that of the material of the high-resistance section 12. The brushes 5a, 5b are disposed so that the high-resistance section 12 is arranged at the back end of a rotating commutator 9 in the rotation direction. Each segment 10 for constituting the commutator 9 slidably contacts with the high-resistance section 12, and separates from the low-resistance section 13 with respect to the brushes 5a, 5b. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a DC machine such as a DC motor.

  As shown in FIG. 6, the DC motor (DC motor) 101 includes magnets 102 and 103, an armature 104, and a brush 105. A plurality of teeth 107a are formed on the core 107 of the armature 104, and a coil 108 is wound around the five teeth 107a. In addition, although illustration is abbreviate | omitted, another coil is similarly wound for every five teeth 107a. The winding method of the DC motor 101 is so-called distributed winding. The armature 104 is provided with a commutator 109. The commutator 109 has a plurality of segments 110, and two brushes 105 are disposed so as to be in sliding contact with the segments 110. Both ends of the coil 108 are connected to two segments 110 adjacent in the circumferential direction.

  In the DC motor 101, a DC current (drive current) flows into the coil 108 through the brush 105 and the segment 110 of the commutator 109. The armature 104 is rotated by the electromagnetic force generated between the magnetic flux generated in the armature 104 and the magnets 102 and 103, and the commutator 109 with which the brush 105 is slidably contacted is changed by the rotation. The direction of the current flowing through the armature 104 is changed, and the armature 104 continuously rotates.

  7A to 7C are schematic views showing the commutator 109 linearly. 7A to 7C, the brush 105 and the segment 110 are shown as being separated from each other, but they are actually in sliding contact with each other.

  As shown in FIG. 7A, the coil 108 connected between the segment 110 in which the brush 105 is in sliding contact and the segment 110 adjacent to the segment 110 in the circumferential direction (right direction in the drawing) A current I flows from left to right. Similarly, a current I flows from the right to the left in the drawing in the segment 110 to which the brush 105 is slidably contacted and the segment 110 and the segment 110 adjacent to the left in the drawing. That is, the brush 105 is supplied with a current (2I) that is twice the current flowing through each coil 108.

  At this time, an induced voltage e is generated in the direction opposite to the current I (from right to left in the figure) due to the influence of the leakage magnetic flux. The induced voltage e is a counter electromotive force induced in the coil 108 due to a change in magnetic flux passing through the coil 108. Then, the armature 104 rotates and the commutator 109 moves to the left with respect to the brush 105 as shown in FIG. Then, the two segments 110 are short-circuited by the brush 105. Further, when the armature 104 rotates, as shown in FIG. 7C, the current I flows from the right to the left in the coil 108, and the induced voltage e is generated in the direction opposite to the current I (from left to right in the figure). To do. That is, when the armature 104 rotates in the order of FIGS. 7A to 7C, the direction of the current I flowing through the coil 108 is reversed. Further, the direction of the induced voltage e generated in the coil 108 is also reversed. Thus, the direction of the current I flowing through the coil 108 is changed, and the direction of the magnetic field in the core 107 wound around the coil 108 is reversed. A rotational force is generated by the electromagnetic force of the coil 108 and the magnetic force from the magnets 102 and 103, and the motor rotates.

As described above, the reversal of the current I flowing through the coil 108 short-circuited by the brush 105 during the short-circuit period is referred to as “rectification”.
Here, as shown by a broken line in FIG. 7D, the induced voltage e changes in the coil 108 being rectified. The induced voltage e gradually changes from the minus side to the plus side with the rotation of the armature 104 as shown in FIGS. 7A to 7C in the rectification section (rotation angle at the time of rectification), In the second half of the rectification period, the induced voltage e is generated in the direction (plus side) that delays rectification. Therefore, as shown by the one-dot chain line in FIG. 7D, the reversal of the current I is delayed with respect to the linear change of the current value (linear rectification which is ideal rectification), and the current at the end of the rectification section I will change rapidly.

In order to solve this deterioration of rectification, for example, by providing an extension for increasing the magnetic flux in the magnet, the amount of magnetic flux is increased. As a result, an induced voltage is generated in the coil, and this induced voltage causes a reactance voltage ( There has been proposed a technique in which the voltage that works in the direction of delaying the change in the short-circuit current is canceled to improve the rectification. (See Patent Document 1).
Japanese Patent Laid-Open No. 2004-23915 (paragraph numbers 0027-0030, FIG. 2)

  By the way, in the motor of patent document 1, since the special magnet (extension part) which raises magnetic flux was used, it was expensive. For this reason, it is conceivable to arrange magnets that generate a uniform magnetic flux in the circumferential direction at approximately 360 ° (full pitch) with respect to the rotation surface of the armature. In such a motor, the induced voltage e generated during rectification becomes high, and delayed rectification as shown in FIG. 7D can be prevented. However, in this motor, as shown in FIG. 8, the current suddenly decreases at the initial stage of commutation, and thus a problem such as generation of vibration of the motor due to the current decrease has occurred.

  The present invention has been made in view of the above circumstances, and an object thereof is to provide a DC machine that is inexpensive and has linear rectification characteristics.

  In order to solve the above problem, the invention according to claim 1 includes an armature formed by winding a coil around a core having a plurality of teeth provided at equiangular intervals in a cylindrical yoke, A plurality of magnets having different polarities along the circumferential direction are attached to the inner side surface of the yoke, and are in sliding contact with a plurality of segments arranged along the circumferential direction of the commutator and connected to the coil. A drive current is supplied to the coil via a plurality of brushes, and a magnet is provided between the teeth on the rear end side in the rotation direction and the teeth adjacent to the rotation direction in the plurality of teeth around which the coil is wound at the start of rectification. In the DC machine arranged at a position where the polarity of the high-resistance part changes, the brush includes a high-resistance part made of a high-resistance material and a low-resistance part made of a material having a lower resistance value than the material of the high-resistance part. Have That it has been deployed from the high-resistance portion in sliding contact with the commutator segments to rotate the gist.

  In the invention according to claim 2, the magnet has a uniform magnetic flux density in the radial direction, and m pieces of different polarities are alternately arranged, and the core has m × n teeth, The coil is wound over n-1 teeth, the commutator has a plurality of commutator segments, is connected to the coil, two brushes are provided, and an axial center of the armature The gist is that they are arranged at intervals of 180 °.

  Further, in the invention according to claim 3, the magnet has a uniform magnetic flux density in the radial direction, and m pieces of different polarities are alternately arranged, and the core has m × n teeth, The coil is wound over n teeth, the commutator has a plurality of commutator segments, is connected to the coil, and two brushes are provided, with respect to the axial center of the armature. The main point is that they are arranged at intervals of 180 °.

  According to a fourth aspect of the present invention, the armature can be rotated in any one of a clockwise direction and a counterclockwise direction, and the brush can be rotated with respect to the rotating commutator. The gist is that the resistance portion is arranged so as to be on the rear end side in the rotation direction.

  Further, in the invention according to claim 5, the armature can be rotated in either one of a clockwise direction and a counterclockwise direction, and the brush can be rotated with respect to the rotating commutator. The gist is that the resistance portions are arranged on both sides in the rotation direction of the brush.

(Function)
According to invention of Claim 1, the induced voltage which generate | occur | produces in a coil becomes large by providing the several magnet which has a different polarity along the circumferential direction over the perimeter. Also, the brush slidably contacts the rotating commutator segment from the high-resistance part, so that the current changes linearly without suddenly decreasing and reversing under the large induced voltage. Will be performed. By adopting such a configuration, it is possible to realize a DC machine that is inexpensive and has linear rectification characteristics.

  According to the invention described in claim 2, the armature is wound with n × 1 teeth with m × n teeth, and two brushes are arranged at an interval of 180 ° with respect to the axis center of the armature. By using, the current value changes linearly from the beginning to the end of the rectification section, and ideal rectification is performed.

  According to the invention described in claim 3, an armature in which m × n teeth are wound around n teeth and two brushes are arranged at an interval of 180 ° with respect to the axis center of the armature is used. As a result, the current value linearly changes from the beginning to the end of the rectification section, and ideal rectification is performed.

  According to the fourth aspect of the present invention, since the high resistance portion is arranged on the rear end side in the rotation direction, the current flowing through the coil is brought into sliding contact with the segment of the commutator where the brush rotates from the high resistance portion. A suitable rectification can be obtained without sudden decrease and inversion.

  According to the fifth aspect of the present invention, since the high resistance portion slides on the commutator segment where the brush rotates, a suitable rectification can be obtained without suddenly decreasing and reversing the current flowing in the coil. . In addition, the rapid change in current at the end of the rectifying section can be suppressed by separating the high resistance portion of the brush from the commutator.

  According to the present invention, it is possible to provide a DC machine that is inexpensive and has linear rectification characteristics.

(First embodiment)
DESCRIPTION OF THE PREFERRED EMBODIMENTS A first embodiment in which the present invention is embodied in an automotive electrical motor as a direct current machine will be described below with reference to the drawings.

FIG. 1 is a schematic configuration diagram illustrating the electrical component motor according to the first embodiment.
As shown in FIG. 1, the motor 1 includes a motor housing (yoke) 6 having a cylindrical portion, and m pieces (two pieces in this embodiment) are formed on the inner peripheral surface of the motor housing 6 in a circular arc shape in cross section. ) Magnets 2 and 3 are attached. The magnets 2 and 3 are each formed in a semi-cylindrical shape having an arc angle of approximately 180 °, and the two approximately 180 ° magnets 2 and 3 constitute a cylindrical magnet of approximately 360 ° (full pitch). The magnets 2 and 3 are magnetized so that their inner peripheral surfaces are different magnetic poles. In this embodiment, the magnet 2 is magnetized to the N pole, and the magnet 3 is magnetized to the S pole. That is, the number of poles of the motor 1 of this embodiment is 2.

The armature 4 is accommodated in the motor housing 6 so as to be surrounded by the magnets 2 and 3.
The armature 4 includes a core 7, coils (windings) 8 a and 8 b wound around the core 7, a commutator (commutator) 9, and a rotating shaft 11, and the core 7 and the commutator 9 are rotated. The shaft 11 is attached so as to be integrally rotatable.

  The core 7 has a plurality of teeth 7a arranged at equal intervals along the circumferential direction, and each tooth 7a is formed in a substantially T-shape extending along the radial direction. The core 7 has n teeth, that is, (m × n) teeth (2 × 6 = 12 teeth in this embodiment) for one magnetic pole. Therefore, the teeth 7 a are formed every 30 ° in the circumferential direction of the armature 4. That is, the adjacent teeth 7a are formed so that an angle (motor armature slot angle) θ formed by the center line thereof is 30 ° (= 360 ° / 12).

  The core 7 has (n-1) (five in this embodiment) teeth 7a as a set, and coils 8a and 8b are wound around the teeth 7a. Although not shown, a plurality of other coils are wound in the same manner with five teeth 7a as a set. That is, the winding method of the motor 1 is so-called distributed winding.

  The commutator 9 is disposed at one end of the armature 4, and has the same number of teeth 7 a, that is, (m × n) (12 in this embodiment) segments (commutator pieces) 10. The segment 10 is formed so that the slits between the segments 10 are located approximately in the middle between the adjacent teeth 7a, that is, the axis O and the slit between the segments and the center between the teeth 7a are aligned substantially in a straight line. ing.

  A coil is connected between two adjacent segments 10. For example, two adjacent segments 10 are set as one set (segment pair), and two sets of segments 10a, 10b, 10c, and 10d that are point-symmetrical with respect to the axial center O of the armature 4 include a coil 8a and a coil. 8b is connected. That is, the coil 8a is connected to the adjacent segments 10a and 10b, and the coil 8b is connected to the adjacent segments 10c and 10d. The coils connected to the two pairs of segments at the point-symmetrical positions are wound around the teeth 7a leaving the teeth 7a facing each other by 180 °. For example, the rotation direction (arrow) of the teeth 7a on the tip side in the rotation direction (arrow X direction) of the five teeth 7a around which the coil 8a is wound and the rotation direction (arrows) of the five teeth 7a around which the coil 8b is wound (X direction) One tooth 7a exists between the teeth 7a on the rear end side.

  The motor 1 has two brushes 5a and 5b. These brushes 5 a and 5 b are arranged at positions facing the axis center O of the armature 4, that is, the rotating shaft 11 (at intervals of 180 °), and are urged so as to be in sliding contact with the commutator 9. A direct current supplied from a direct current power source (not shown) flows into the coils 8 a and 8 b through the brushes 5 a and 5 b and the segment 10 of the commutator 9. When a direct current flows into the coils 8a and 8b, the armature 4 starts to rotate due to the electromagnetic force generated by the magnetic field generated in the armature 4 by the direct current and the magnetic fields of the magnets 2 and 3. Then, a pair of adjacent segments 10a and 10b are in contact with the brush 5a, a pair of adjacent segments 10c and 10d are in contact with the brush 5b, and the segment 10 is interposed between the brushes 5a and 5b. Short circuit. As a result, the direction of the current flowing through the coils 8a and 8b is changed, and the armature 4 continues to rotate in the clockwise direction (the arrow X direction in the figure).

  In the present embodiment, twelve segments 10 are provided every 30 ° in the circumferential direction, and when the armature 4 rotates 30 ° in the rectifying section with respect to the brushes 5a and 5b, the coils 8a and 8b that are being rectified. The direction of current is changed. That is, the coils 8a and 8b are rectified by the 30 ° rotation of the armature 4.

  The position of the armature 4 shown in FIG. 1 indicates the middle position of the rectification section when the armature 4 rotates in the X direction. That is, at the middle position of the rectifying section, the approximate center between the plurality of coils in the rectifying state (two coils 8a and 8b rectified by the two brushes 5a and 5b in this embodiment) is the magnetic pole on the stator side. The configurations of the magnets 2 and 3, the brushes 5 a and 5 b, and the armature 4 are set so as to substantially coincide with the boundary position. Incidentally, the commutation start position is rotated by a half slot in the direction opposite to the direction of the arrow X, and the boundary where the poles of the magnets 2 and 3 change is located between the teeth 7a and 7a, that is, in FIG. Is set as follows. That is, the configuration of the motor 1 including the armature 4 having the (m × n) teeth 7a and the coils 8a and 8b wound around the (n−1) teeth 7a The intermediate point between the tooth at the rear end in the rotation direction of the wound tooth 7a and the tooth adjacent to the rotation direction in the rotation direction is set to substantially coincide with the boundary point of the magnetic pole at the start of rectification.

  In this embodiment, the angle between the segments 10 is set to be the same as the angle θ between the teeth 7a, and the contact width angle corresponding to the contact width between the brushes 5a, 5b and the segment 10 is between the teeth 7a. Is set to the same angle θ. The rotation angle of the armature 4 corresponding to the rectifying section of each coil 8a, 8b also corresponds to the angle θ between the teeth 7a.

  Each of the brushes 5a and 5b has a two-layer structure including a high resistance portion 12 made of a high resistance material and a low resistance portion 13 made of a material having a resistance value lower than that of the material of the high resistance portion 12. have. The brushes 5 a and 5 b are formed so that the high resistance portion 12 and the low resistance portion 13 are in sliding contact with the segment 10. Further, the brushes 5a and 5b are arranged so that the high resistance portion 12 is on the rear end side in the rotation direction with respect to the rotating commutator 9. Accordingly, each segment 10 constituting the commutator 9 is in sliding contact with the brushes 5 a and 5 b from the high resistance portion 12 and is separated from the low resistance portion 13. In other words, the brushes 5 a and 5 b are in sliding contact with the segments 10 from the high resistance portion 12 and are separated from the low resistance portion 13.

In addition, the width | variety of the high resistance part 12 shall be a little narrower than the half of the width | variety of brush 5a, 5b.
Next, the rectifying characteristic according to the present invention will be described with reference to FIG. 2A to 2C are schematic configuration diagrams for explaining the rectification characteristics. FIG. 2D is a graph for explaining the rectification characteristics. In FIGS. 2A to 2C, the brush 5a and the segments 10a and 10b are illustrated as being separated from each other, but are actually in sliding contact with each other.

  As shown in FIG. 2A, a current I flows from the left to the right in the drawing in the coil 8a connected between the segment in which the brush is in sliding contact and the segment adjacent to the segment in the circumferential direction. ing.

  At this time, an induced voltage e is generated in the direction opposite to the current I (from right to left in the figure) due to the influence of the leakage magnetic flux. The induced voltage e is a counter electromotive force induced in the coil 8a due to a change in magnetic flux passing through the coil 8a. Then, the armature 4 rotates and the commutator 9 moves to the left with respect to the brush 5a as shown in FIG. 2B (the position of the armature in FIG. 1). Then, the two segments 10a and 10b are short-circuited by the brush 5a. Further, when the armature 4 rotates, as shown in FIG. 2C, the current I flows from the right to the left in the coil 8a, and the induced voltage e is generated in the direction opposite to the current I (from left to right in the figure). To do. That is, when the armature 4 rotates in the order of FIGS. 2 (a) → (b) → (c), the direction of the current I flowing through the coil 8a at that time is reversed. Further, the direction of the induced voltage e generated in the coil 8a is also reversed. Thus, the direction of the current I flowing through the coil 8a is changed, and the direction of the magnetic field in the core 7 wound around the coil 8a is reversed. A rotational force is generated by the electromagnetic force of the coil 8a and the magnetic force from the magnets 2 and 3, and the motor 1 rotates.

  In the arrangement of the conventional magnets 102 and 103 as shown in FIG. 6, since the induced voltage e generated in the coil 108 being rectified is small, the delay rectification has already been described. The induced voltage e can be increased by arranging the magnet so that the induced voltage e can be increased, that is, the arrangement of about 360 ° (full pitch). However, at the moment when the segment is short-circuited by the brush, the current is suddenly decreased and reversed by the action of the induced voltage e, and the rectification is completed. This state does not generate sparks, but is a fatal problem for motors that require low vibration.

  However, in this embodiment, as shown in FIG. 1, a magnet arrangement that can increase the induced voltage e during rectification, that is, an arrangement of about 360 ° (full pitch) is adopted. Furthermore, since the high resistance portion 12 is arranged on the rear end side in the rotation direction with respect to the commutator 9 in which the brushes 5a and 5b rotate, as shown in FIG. The current changes linearly and ideal rectification is performed.

As described above, the present embodiment has the following effects.
(1) The induced voltage e generated in the coils 8a and 8b is increased by providing the plurality of magnets 2 and 3 having different polarities along the circumferential direction over the entire circumference (360 ° full pitch). Further, the brushes 5a and 5b are brought into sliding contact with the segment 10 of the rotating commutator 9 from the high resistance portion 12, so that the current I is linearly reduced and not reversed rapidly under the large induced voltage e. Thus, ideal rectification is performed. By adopting such a configuration, it is possible to realize a DC machine that is inexpensive and has linear rectification characteristics.

  (2) The armature 4 in which the m × n teeth 7 a are wound around the n−1 teeth 7 a and the two brushes 5 a and 5 b are arranged at an interval of 180 ° with respect to the rotating shaft 11 of the armature 4. By using, the current value changes linearly from the beginning to the end of the rectification section, and ideal rectification is performed.

  (3) With respect to the commutator 9 in which the high resistance portion 12 rotates, the current flowing in the coils 8a and 8b is preferably reduced without being rapidly reversed and reversed because it is arranged on the rear end side in the rotation direction. Rectification can be obtained.

  (4) Since the commutation is ideally performed, the vibration of the motor 1 is extremely reduced. In addition, there is no occurrence of sparks, and problems such as noise and electromagnetic noise, and wear of the brushes 5a and 5b are suitably suppressed.

In addition, you may change the said embodiment as follows.
In the above embodiment, the coils 8a and 8b are wound around the five teeth 7a as a set. However, the winding mode of the coils 8a and 8b is limited to this. It is not something. For example, as shown in FIG. 3, the coils 8a and 8b may be wound around a set of six teeth (the winding angle of the coils 8a and 8b is 180 °). The start position of commutation in the motor configured as described above is set to a position substantially shown in FIG. That is, this motor has (m × n) teeth 7a, and (n) a plurality of coils in which the coils 8a and 8b are wound around the teeth 7a. The intermediate point between the tooth on the rear end side in the rotational direction of the teeth 7a and the tooth adjacent in the rotational direction is set to substantially coincide with the boundary point of the magnetic pole at the start of commutation. Also in the motor configured as described above, ideal rectification characteristics (characteristics in which the value of the current flowing through the coil changes linearly) can be obtained as in the above embodiment.

(Second Embodiment)
Hereinafter, a second embodiment of the present invention will be described with reference to FIG. In addition, about the structure similar to 1st Embodiment, the same code | symbol is attached | subjected to drawing and the detailed description is abbreviate | omitted.

FIG. 4 is a schematic configuration diagram illustrating a motor according to the second embodiment. Note that the motor shown in FIG. 4 shows an intermediate position in the commutation section, like the motor shown in FIG.
Instead of the two magnets 2 and 3 (FIG. 1) having an arc angle of approximately 180 ° in the first embodiment, approximately 360 ° (full pitch) by four magnets 22, 23, 24, and 25 having an arc angle of approximately 90 °. A cylindrical magnet is formed. Further, the motor 21 of the present embodiment includes four brushes 5a, 5b, 5c, and 5d.

  As shown in FIG. 4, the motor 21 of this embodiment includes a motor housing (yoke) 6 having a cylindrical portion, and m pieces (this embodiment) are formed on the inner peripheral surface of the motor housing 6 in a circular arc shape in cross section. Four magnets 22, 23, 24, 25 are attached in the form. In the present embodiment, for example, the magnets 22 and 24 are magnetized to the N pole, and the magnets 23 and 25 are magnetized to the S pole. That is, the number of poles of the motor 1 of this embodiment is four.

The armature 4 is accommodated in the motor housing 6 so as to be surrounded by the magnets 22, 23, 24, 25.
The armature 4 includes a core 7, coils (windings) 8 a, 8 b, 8 c, 8 d wound around the core 7, a commutator (commutator) 9, and a rotating shaft 11. The commutator 9 is attached to the rotary shaft 11 so as to be integrally rotatable.

  The core 7 has n teeth, that is, (m × n) teeth (4 × 3 = 12 teeth in the present embodiment) for one magnetic pole. Therefore, the teeth 7 a are formed every 30 ° in the circumferential direction of the armature 4. That is, the adjacent teeth 7a are formed so that an angle (motor armature slot angle) θ formed by the center line thereof is 30 ° (= 360 ° / 12).

  Coils 8a, 8b, 8c, and 8d are wound around the core 7 as a set of (n-1) (two in this embodiment) teeth 7a. Although not shown, a plurality of other coils are wound in the same manner with two teeth 7a as one set. That is, the winding method of the motor 1 is so-called distributed winding.

  The commutator 9 is disposed at one end of the armature 4, and has the same number of teeth 7 a, that is, (m × n) (12 in this embodiment) segments (commutator pieces) 10. The segment 10 is formed so that the slits between the segments 10 are located approximately in the middle between the adjacent teeth 7a, that is, the axis O and the slit between the segments and the center between the teeth 7a are aligned substantially in a straight line. ing.

  A coil is connected between two adjacent segments 10. For example, two adjacent segments 10 are set as one set (segment pair), and four sets of segments 10 a, 10 b, segments 10 c, 10 d, segments 10 e, 10 f, which are in point symmetry with respect to the axis center O of the armature 4, Coils 8a, 8b, 8c and 8d are connected to the segments 10g and 10h. That is, the coil 8a is connected to the adjacent segments 10a and 10b, the coil 8b is connected to the adjacent segments 10c and 10d, the coil 8c is connected to the adjacent segments 10e and 10f, and the adjacent segments 10g and 10h. Is connected to a coil 8d. The coils respectively connected to the four pairs of segments at the point-symmetrical positions are wound around the teeth 7a leaving the teeth 7a facing each other by 180 °. For example, the rotational direction (arrow X direction) of the two teeth 7a wound with the coil 8a and the rotational direction (arrow indicated by the arrow 7) of the two teeth 7a wound with the coil 8b are shown. (X direction) One tooth 7a exists between the teeth 7a on the rear end side.

  The four brushes 5 a, 5 b, 5 c, 5 d are arranged at 90 ° intervals with respect to the axial center O of the armature 4, that is, the rotating shaft 11, and are urged so as to be in sliding contact with the commutator 9. It is arranged.

  A direct current supplied from a direct current power source (not shown) flows into the coils 8 a, 8 b, 8 c and 8 d through the brushes 5 a, 5 b, 5 c and 5 d and the segment 10 of the commutator 9. When a direct current flows into the coils 8a, 8b, 8c, and 8d, the armature 4 starts to rotate by an electromagnetic force generated by the magnetic field generated in the armature 4 by the direct current and the magnetic fields of the magnets 22, 23, 24, and 25.

  Then, a pair of adjacent segments 10a and 10b are in contact with the brush 5a, and a pair of adjacent segments 10c and 10d are in contact with the brush 5b. Also, a pair of adjacent segments 10e and 10f are in contact with the brush 5c, a pair of adjacent segments 10g and 10h are in contact with the brush 5d, and the brushes 5a, 5b, 5c, Short circuit through 5d. As a result, the direction of the current flowing through the coils 8a and 8b is changed, and the armature 4 continues to rotate in the clockwise direction (the arrow X direction in the figure).

  In the present embodiment, twelve segments 10 are provided every 30 ° in the circumferential direction, and when the armature 4 rotates 30 ° in the rectifying section with respect to the brushes 5a, 5b, 5c, and 5d, The direction of the current of the coils 8a, 8b, 8c, 8d is changed. That is, the coils 8a, 8b, 8c, and 8d are rectified by the rotation of the armature 4 by 30 °.

  In the present embodiment, the angle between the segments 10 is set to be the same as the angle θ between the teeth 7a, and the contact width angle corresponding to the contact width between the brushes 5a, 5b, 5c, 5d and the segment 10 is It is set to be the same as the angle θ between the teeth 7a.

  Each of the brushes 5a, 5b, 5c, and 5d includes a high resistance portion 12 made of a high resistance material and a low resistance portion 13 made of a material having a lower resistance value than the material of the high resistance portion 12. It has a two-layer structure. The brushes 5 a, 5 b, 5 c, and 5 d are formed so that the high resistance portion 12 and the low resistance portion 13 are in sliding contact with the segment 10. Further, the brushes 5a, 5b, 5c, and 5d are arranged such that the high resistance portion 12 is on the rear end side in the rotation direction with respect to the rotating commutator 9. Therefore, each segment 10 constituting the commutator 9 is in sliding contact with the brushes 5 a, 5 b, 5 c, and 5 d from the high resistance portion 12 and is separated from the low resistance portion 13. In other words, each brush 5 a, 5 b, 5 c, 5 d is in sliding contact with each segment 10 from the high resistance portion 12 and is separated from the low resistance portion 13.

Note that the width of the high resistance portion 12 is slightly narrower than half of the width of the brushes 5a, 5b, 5c, and 5d.
With such a configuration, a large induced voltage e is generated by arranging the magnets 22, 23, 24, and 25 in the same manner as in the first embodiment or in conformity thereto. The brushes 5a, 5b, 5c, and 5d are arranged so that the high resistance portion 12 is on the rear end side in the rotation direction with respect to the rotating commutator 9, and under this large induced voltage e, Rectification can be realized ideally in which the current I changes linearly from the beginning to the end of the rectification interval without suddenly decreasing and reversing.

According to the second embodiment described above, it is possible to obtain the same effects as the effects (1), (3), and (4) according to the previous first embodiment, or effects equivalent thereto.
(Third embodiment)
Hereinafter, a third embodiment of the present invention will be described with reference to FIG. In addition, about the structure similar to 1st Embodiment, the same code | symbol is attached | subjected to drawing and the detailed description is abbreviate | omitted.

FIG. 5 is a schematic configuration diagram illustrating a motor according to the third embodiment. In addition, the motor shown in FIG. 5 has shown the intermediate position of the commutation area like the motor shown in FIG. 1, FIG.
As shown in FIG. 5, the motor 31 of the present embodiment includes brushes 5e and 5f instead of the brushes 5a and 5b (FIG. 1) of the first embodiment. Further, the motor 31 of the present embodiment is a one-turn motor.

  As shown in FIG. 5, the motor 31 includes magnets 2, 3, an armature 4, brushes 5e, 5f, and the like. More specifically, the motor 31 of the present embodiment is a two-pole DC motor, and in the motor housing (yoke) 6, two magnets 2, 3 having an arcuate cross section forming an N pole and an S pole are provided. The armature 4 is disposed opposite to the armature 4. The two magnets 2 and 3 are each formed in a semi-cylindrical shape with an arc angle of approximately 180 °, and are arranged point-symmetrically with respect to the axial center O of the armature 4. The two magnets 2 and 3 of about 180 ° constitute a cylindrical magnet of about 360 ° (full pitch).

  The armature 4 includes a core 7, coils (windings) 8 a and 8 b wound around the core 7, a commutator (commutator) 9, and a rotating shaft 11, and the core 7 and the commutator 9 are rotated. The shaft 11 is attached so as to be integrally rotatable. Then, it is driven to rotate in the direction of the arrow in FIG. 4 (clockwise direction) based on the direction of the supplied direct current. That is, when the current is supplied as shown in FIG. 2 described above, the rotation is clockwise.

  The brushes 5e and 5f each have a two-layer structure including a high resistance portion 12 made of a high resistance material and a low resistance portion 13 made of a material having a lower resistance value than the material of the high resistance portion 12. ing. The brushes 5e and 5f are formed so that the high resistance portion 12 and the low resistance portion 13 are in sliding contact with the segment 10. Further, the brushes 5e and 5f have the high resistance portions 12 arranged on both sides of the brushes 5e and 5f with respect to the rotating commutator 9. Accordingly, each segment 10 constituting the commutator 9 is in sliding contact with the brushes 5 e and 5 f from the high resistance portion 12, passes through the low resistance portion 13, and is separated from the high resistance portion 12. In other words, the brushes 5 a and 5 b are in sliding contact with the segments 10 from the high resistance portion 12 and are separated from the high resistance portion 12 through the low resistance portion 13.

Note that the width of the high resistance portion 12 is slightly narrower than half the width of the brushes 5e and 5f.
That is, the high resistance portion 12 is provided on the front end side and the rear end side of the brushes 5e and 5f with respect to the rotating commutator 9 (so-called both sides of the brushes 5e and 5f), and the low resistance portion 13 includes the brush 5e, The other part of 5f, that is, the central part is provided.

  By adopting such a configuration, a large induced voltage e is generated by arranging the magnets 2 and 3 in the same manner as in the first embodiment or in conformity thereto. Since the high resistance portions 12 are provided on both sides of the brushes 5e and 5f, the current I does not rapidly decrease and invert under the large induced voltage e, but linearly from the beginning to the end of the rectifying section. The ideal rectification can be realized by changing. In the latter half of rectification, the high resistance portion 12 is provided on the tip side (arrow X direction side) with respect to the rotating commutator 9, so that delayed rectification occurs, but the induced voltage e is originally increased, Since the influence of the high resistance portion 12 works strongly on the acceleration side (the rear end side with respect to the rotating commutator 9), the influence of the delayed rectification is small.

  According to the third embodiment described above, it is possible to obtain the same effects as the effects (1), (2), and (4) of the previous first embodiment, or an effect equivalent thereto, and a new one. In addition, the following effects can be obtained.

  (5) Since the high resistance portions 12 are provided on both sides of the brushes 5e and 5f, the brushes 5e and 5f flow into the coils 8a and 8b by slidingly contacting the segment 10 of the commutator 9 from which the brushes 5e and 5f rotate. The current can be suitably rectified without rapidly decreasing and reversing. Further, when the high resistance portions 12 of the brushes 5e and 5f are separated from the commutator 9, a rapid change in current at the end of the commutator section can be suppressed.

(Other embodiments)
Other elements that can be changed in common with the above embodiments include the following.
In each of the above embodiments, the magnets are composed of two 180 ° magnets 2 and 3 or four 90 ° magnets 22, 23, 24, and 25 and constitute a 360 ° (full pitch) magnet. One 360 ° magnet may be configured as a 360 ° magnet.

The schematic block diagram which shows the DC machine of 1st Embodiment. (A)-(d) is a schematic block diagram and graph for demonstrating the rectification | straightening characteristic concerning this invention. The schematic block diagram which shows the modification of the DC machine of 1st Embodiment. The schematic block diagram which shows the DC machine of 2nd Embodiment. The schematic block diagram which shows the DC machine of 3rd Embodiment. The schematic block diagram of the conventional DC motor. (A)-(d) is a schematic block diagram and graph for demonstrating the conventional rectification characteristic. The graph explaining other conventional rectification characteristics.

Explanation of symbols

  1, 2, 31, ... motor 2, 3, 22, 23, 24, 25, 102, 103 ... magnet, 4 ... armature, 5a, 5b, 5c, 5d, 5e, 5f ... brush, 6 ... motor housing, 7 ... Core, 7a ... Teeth, 8a, 8b, 8c, 8d, 108 ... Coil, 9 ... Commutator, 10, 10a, 10b, 10c, 10d, 10e, 10f, 10g, 10h ... Segment (commutator piece), 11 ... rotation axis, 12 ... high resistance part, 13 ... low resistance part, O ... axis center.

Claims (5)

An armature constructed by winding a coil around a core having a plurality of teeth provided at equal angular intervals is enclosed in a cylindrical yoke, and the inner surface of the yoke is circumferentially extended along the entire circumference. A plurality of magnets having different polarities are attached, and a drive current is supplied to the coil via a plurality of brushes which are arranged along the circumferential direction of the commutator and are slidably contacted with the plurality of segments connected to the coil. In the DC machine in which the polarity of the magnet changes between the teeth on the rear end side in the rotation direction and the teeth adjacent to the rotation direction in the plurality of teeth on which the coil is wound at the start,
The brush has a high resistance portion made of a high resistance material and a low resistance portion made of a material having a resistance value lower than that of the material of the high resistance portion, and the segment of the rotating commutator has a high resistance portion. A direct current machine arranged so as to be in sliding contact. The magnet has a uniform magnetic flux density in the radial direction, and is alternately arranged with m different polarities,
The core has m × n teeth,
The coil is wound over n-1 teeth,
The commutator has a plurality of commutator segments and is connected to the coil;
2. The DC machine according to claim 1, wherein two brushes are provided and arranged at an interval of 180 ° with respect to an axis center of the armature. The magnet has a uniform magnetic flux density in the radial direction, and is alternately arranged with m different polarities,
The core has m × n teeth,
The coil is wound over n teeth,
The commutator has a plurality of commutator segments and is connected to the coil;
2. The DC machine according to claim 1, wherein two brushes are provided and arranged at an interval of 180 ° with respect to an axis center of the armature. The armature is rotatable in either one of a clockwise direction or a counterclockwise direction,
4. The direct current according to claim 1, wherein the brush is arranged so that the high resistance portion is on a rear end side in a rotation direction with respect to the rotating commutator. 5. Machine. The armature is rotatable in either one of a clockwise direction or a counterclockwise direction,
4. The DC machine according to claim 1, wherein the brush has the high resistance portion disposed on both sides of the rotating direction of the brush with respect to the rotating commutator. 5.

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