JP2010110111A - Electric motor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To enhance motor efficiency in an electric motor which has four magnetic poles and is equipped with three brushes in order to switch the rotational speed. <P>SOLUTION: Each winding includes a first coil winding 81a which is wound forward to surround four teeth of an armature core adjoining each other, and a second coil winding 81b which is connected in series with the first coil winding 81a, arranged contiguously to the four teeth 12 around which the first coil winding 81a is wound, and is wound reversely to surround the four teeth adjoining each other. A magnet 7a is arranged in a housing to face a position where the first coil winding 81a of winding 14A and the magnet 7a overlap in the radial direction when an armature 6 is arranged rotationally to slide in the position where the boundary 15a of adjacent segments connected with the winding 14A and the center of a first brush 21a substantially overlap in the radial direction. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an electric motor mounted on a vehicle, for example.

  Conventionally, an electric motor with a brush is often used as a wiper motor for an automobile. In this type of electric motor, a plurality of permanent magnets are arranged at an equal pitch in the circumferential direction on the inner peripheral surface of a cylindrical yoke, and an armature is rotatably supported inside these permanent magnets. The armature has an armature core in which a plurality of teeth are formed radially. A plurality of slots that are long in the axial direction are formed between the teeth, and a coil is formed by winding a winding by a lap winding method between slots having a predetermined interval. The coil is electrically connected to a commutator that is externally fixed to the rotating shaft so as to be adjacent to the armature core.

  In the commutator, a plurality of segments, which are metal pieces, are arranged in the circumferential direction in a state of being insulated from each other, and a winding start end and a winding end end of a coil are connected to these segments, respectively. Each segment is slidably connected to the brush, and power is supplied to each coil via the brush. A magnetic field is formed in the supplied coil, and the rotating shaft is driven by a magnetic attractive force or a repulsive force generated between the yoke and the permanent magnet.

  Here, due to the recent demand for smaller and higher performance wiper motors, the number of magnetic poles has been increased to 4 poles (pole pair number: 2), the slots have been increased, the motor performance has been improved, and three brushes have been circumferentially moved. (See, for example, Patent Document 1).

  The electric motor of Patent Document 1 includes a low-speed brush and a high-speed brush that are selectively connected to the positive electrode of the power source, and a common brush that is connected to the negative electrode of the power source. Here, the low-speed brush and the common brush are arranged at a position 90 degrees apart from the mechanical angle, and the high-speed brush is arranged at a position away from the low-speed brush by an angle corresponding to a predetermined advance angle. . The motor speed can be varied by selectively switching energization to the low speed brush and the high speed brush.

  Normally, when a low-speed brush and a high-speed brush as described above are employed in a 4-pole motor, two common brushes arranged at a mechanical angle of 180 degrees, and these common brushes, Two low-speed brushes arranged at positions 90 degrees apart from each other are required, and two high-speed brushes arranged at positions separated by a predetermined angle with respect to these low-speed brushes. That is, a total of six brushes are required.

  In order to reduce the number of brushes of a four-pole motor capable of variable speed, which requires a large number of brushes, the motor of Patent Document 1 uses segments that are arranged at point-of-contrast positions to each other by means of pressure equalization lines. Thus, a method is adopted in which the number of brushes that normally required six is reduced to three (for example, Patent Document 1).

  On the other hand, in order to improve the motor efficiency of the electric motor, as a means for reducing the armature reaction, a method of moving and adjusting the attachment position of the brush or magnet in the rotation direction has been proposed (for example, Patent Document 2). The method of moving and adjusting the mounting position of the brush or magnet in the rotational direction in this way to improve the motor efficiency of the electric motor is that the above-described number of magnetic poles is four and the motor having three brushes for switching the rotational speed is used. Is also required to apply.

Further, in order to cause a large difference in rotational speed, the high-speed brush among the three brushes described above is arranged at a predetermined angle more than a considerable angle with respect to the low-speed brush. When the current is selectively energized, the internal resistance of the electric circuit formed in the armature coil between the high speed brush and the common brush decreases. Therefore, it is assumed that the current value of the current supplied from the high-speed brush to the electric motor increases excessively, and in particular, the lock current generated when the electric motor is locked by an external load becomes excessive.
JP 2007-143278 A JP 2008-99424 A

  Therefore, in an electric motor having four magnetic poles and three brushes for switching the rotation speed, the brush or magnet mounting position is set in the rotation direction as means for reducing armature reaction in order to improve motor efficiency. Application of a method for adjusting the movement to an appropriate position is required.

  Furthermore, when the high-speed brush is selectively energized, the high-speed brush is separated from the low-speed brush by more than a considerable angle in order to prevent the current value of the current flowing through the electric motor from excessively increasing. It is required to arrange at an appropriate position, not at the position.

  Therefore, the present invention has been made in view of the above-described circumstances, and in an electric motor having four magnetic poles and three brushes for switching the rotation speed, the motor efficiency is improved, and the high speed is achieved. An object of the present invention is to prevent an excessive increase in the value of the current flowing through the electric motor when the brush is selectively energized.

  In order to solve the above-mentioned problem, the invention described in claim 1 includes a housing which is a magnetic yoke, four magnets fixed on the inner wall of the housing at a substantially equal pitch, a rotation shaft, and the rotation. An armature core fixed on the shaft and having a plurality of radially formed teeth; a commutator fixed on the rotating shaft at a predetermined interval from the armature core; and having a plurality of segments; and the armature core An armature coil having a plurality of wound windings and a plurality of pressure equalizing lines connecting a pair of segments arranged at a mechanical angle of 180 degrees to each other of the commutator, and surrounded by the four magnets The armature that is arranged and is rotatably supported on the housing, and can slide on the commutator segment of the armature An electric motor comprising a plurality of brushes, wherein the number of teeth is 18, the number of segments is 18, the number of windings is 18, and the brush is connected to the first power supply terminal. First and second brushes that are selectively connected, and a third brush that is connected to a second power supply terminal, wherein the first brush has a mechanical angle with respect to the third brush. The second brush is disposed at a position apart from the first brush by a mechanical angle of 180 degrees with respect to the first brush, and each of the windings is disposed at a position approximately 90 degrees apart. A first coil winding wound in a forward direction around four adjacent teeth of the armature core, and connected in series to the first coil winding, the first coil winding being It is placed next to the four wound teeth and A second coil winding wound around the four teeth adjacent to each other in the opposite direction, and ends of the first and second coil windings are respectively connected to segments adjacent to each other, Any one of the windings is connected so that the boundary between adjacent segments and the center of the first brush are in sliding contact with each other at a position where they substantially coincide with each other in the radial direction of the rotating shaft. When the armature is rotationally arranged, the first coil winding of any one of the windings and any one of the four magnets face each other at a position where they overlap in the radial direction. The four magnets are arranged in the housing.

  According to the second aspect of the present invention, the housing is a magnetic yoke, the four magnets are fixed on the inner wall of the housing at a substantially equal pitch, the rotation shaft, and the rotation shaft is fixed on the rotation shaft and formed radially. An armature core having a plurality of teeth, a commutator having a plurality of segments fixed to the armature core on the rotating shaft at a predetermined interval, and a plurality of windings wound around the armature core. An armature coil having a plurality of pressure equalizing lines that connect a pair of segments arranged at a mechanical angle of 180 degrees to each other of the commutator, and are surrounded by the four magnets and rotated to the housing An electric motor comprising an armature that is supported and a plurality of brushes that are slidable on a segment of the commutator of the armature The number of teeth is 18, the number of segments is 18, the number of windings is 18, and the brush is selectively connected to a first power supply terminal. 1st and 2nd brush, and 3rd brush connected to 2nd electric power supply terminal, The said 1st brush is a position where the mechanical angle was about 90 degree | times away with respect to the said 3rd brush The second brush is disposed at a position apart from the first brush by a mechanical angle of 180 degrees with respect to the first brush, and each of the windings is connected to each other of the armature core. A first coil winding wound in the forward direction surrounding four adjacent teeth, and four coils connected in series to the first coil winding and wound with the first coil winding Four teeth that are placed next to each other and adjacent to each other And end portions of the first and second coil windings are connected to segments adjacent to each other, and any one of the windings. When the armature is rotationally arranged such that two windings are connected and the boundary portion between adjacent segments and the center of the third brush are in sliding contact with each other at a position where they substantially coincide with each other in the radial direction of the rotation shaft The four magnets are disposed in the housing such that the first coil winding of any one of the windings and any one of the four magnets face each other at a position where they overlap each other in the radial direction. Is arranged.

  Furthermore, the invention according to claim 3 is the electric motor according to claim 1 or 2, wherein the center of the first coil winding of any one of the windings in the circumferential direction, 3. The four magnets are arranged in the housing so that the circumferential center of one of the magnets is substantially overlapped with each other in the radial direction. Electric motor.

  On the other hand, the invention described in claim 6 is a housing that is a magnetic yoke, four magnets fixed on the inner wall of the housing at a substantially equal pitch, a rotating shaft, and a radial shaft fixed on the rotating shaft. An armature core having a plurality of teeth formed thereon, a commutator having a plurality of segments fixed to the armature core on the rotating shaft at a predetermined interval, and a plurality of windings wound around the armature core. An armature coil having a wire, and a plurality of pressure equalizing wires connecting a pair of segments arranged at a mechanical angle of 180 degrees to each other of the commutator, and surrounded by the four magnets, the housing An armature rotatably supported on the armature, and a plurality of brushes slidable on the commutator segment of the armature The motor has 18 teeth, 18 segments, 18 windings, and the brush is selectively connected to the first power supply terminal. 1st and 2nd brush, and 3rd brush connected to 2nd electric power supply terminal, The said 1st brush is a position where the mechanical angle was about 90 degree | times away with respect to the said 3rd brush The second brush is disposed at a position apart from the first brush by a mechanical angle of 180 degrees with respect to the first brush, and each of the windings is connected to each other of the armature core. A first coil winding wound in the forward direction surrounding four adjacent teeth, and four coils connected in series to the first coil winding and wound with the first coil winding Four tees placed next to each other and adjacent to each other A second coil winding wound in the opposite direction around the end, and the ends of the first and second coil windings are connected to adjacent segments, respectively, When the armature is rotationally arranged so that the first coil winding of one winding and any one of the four magnets are opposed to each other in a radial direction, the first coil winding The first brush is arranged such that the circumferential center of the brush is connected to any one of the windings and the boundary between adjacent segments is substantially coincident in the radial direction of the rotating shaft. Has been placed.

  According to the seventh aspect of the present invention, the housing is a magnetic yoke, the four magnets are fixed on the inner wall of the housing at a substantially equal pitch, the rotating shaft, and are fixed on the rotating shaft and formed radially. An armature core having a plurality of teeth, a commutator having a plurality of segments fixed to the armature core on the rotating shaft at a predetermined interval, and a plurality of windings wound around the armature core. An armature coil having a plurality of pressure equalizing lines that connect a pair of segments arranged at a mechanical angle of 180 degrees to each other of the commutator, and are surrounded by the four magnets and rotated to the housing An electric motor comprising: an armature supported in a possible manner; and a plurality of brushes slidably contactable with the commutator segment of the armature. The number of teeth is 18, the number of segments is 18, the number of windings is 18, and the brush is selectively connected to a first power supply terminal. 1 and 2 and a third brush connected to a second power supply terminal, wherein the first brush is at a position where the mechanical angle is approximately 90 degrees away from the third brush. The second brush is disposed at a position apart from the first brush by a mechanical angle of 180 degrees with respect to the first brush, and each of the windings is adjacent to the armature core. A first coil winding wound in the forward direction around the four teeth, and four teeth connected in series to the first coil winding and wound with the first coil winding Is placed next to each other and surrounds four teeth adjacent to each other And end portions of the first and second coil windings are respectively connected to the segments adjacent to each other, and any one of the windings When the armature is rotated so that the first coil winding of the winding and one of the four magnets are opposed to a position where they overlap each other in the radial direction, The third brush is arranged such that the circumferential center and any one of the windings are connected and the boundary between adjacent segments is substantially coincident in the radial direction of the rotating shaft. ing.

  Furthermore, the invention according to claim 8 is the electric motor according to claim 6 or 7, wherein the circumferential center of the first coil winding of any one of the windings, The four magnets are arranged in the housing so that the circumferential center of one of the magnets substantially overlaps each other in the radial direction.

  Thus, when the relative positions of the first or third brush and the magnet are set as shown above, a so-called advance angle is provided with respect to the neutral position which is the position of the brush when the armature reaction is not considered. The brush can be arranged at the position where the armature reaction generated in the electric motor can be reduced, and the motor efficiency can be improved.

 By setting the relative positions of the first or third brush and the magnet as shown above, the armature reaction that occurs in the electric motor can be reduced, and the motor efficiency can be improved.

Next, embodiments of the present invention will be described with reference to the drawings.
As shown in FIGS. 1 to 3, the motor 1 with a speed reducer is used as, for example, a wiper motor of an automobile, and includes an electric motor 2 and a speed reducing mechanism 4 connected to a rotating shaft 3 of the electric motor 2. And.
The electric motor 2 includes a bottomed cylindrical yoke 5 and an armature 6 rotatably provided in the yoke 5.

The cylindrical portion 53 of the yoke 5 is formed in a substantially cylindrical shape, and four segment-type permanent magnets (magnets) 7 are arranged on the inner peripheral surface so that the magnetic poles are in order at a constant pitch in the circumferential direction. Yes. That is, the permanent magnet 7 provided on the yoke 5 has a pole pair number of two.
The bottom wall (end portion) 51 of the yoke 5 is formed with a boss portion 19 projecting outward in the axial direction at the radial center, and a bearing 18 for supporting one end of the rotary shaft 3 is provided here. ing.

  An outer flange portion 52 is provided in the opening portion 53 a of the cylindrical portion 53. Bolt holes (not shown) are formed in the outer flange portion 52. Bolts 24 are inserted into the bolt holes and screwed into bolt holes (not shown) formed in a gear housing 23 (described later) of the speed reduction mechanism 4, whereby the yoke 5 is fastened and fixed to the speed reduction mechanism 4.

  The armature 6 includes an armature core 8 that is externally fitted and fixed to the rotary shaft 3, an armature coil 9 that is wound around the armature core 8, and a commutator 10 that is disposed on the other end side of the rotary shaft 3. The armature core 8 is formed by laminating a plate of magnetic material punched by pressing or the like in the axial direction (laminated core), or pressure-molding soft magnetic powder (a dust core). Thus, it has a substantially annular core body 11.

  On the outer periphery of the core body 11, 18 teeth 12 that are substantially T-shaped in a plan view in the axial direction are radially provided at equal intervals along the circumferential direction. Each of the teeth 12 includes a winding drum portion 31 in which the winding 14 is wound in a radial direction, and a peripheral wall provided at the tip of the winding drum portion 31 so as to be symmetrical with respect to the winding drum portion 31. Part 32. That is, the peripheral wall portion 32 provided at the tip of the tooth 12 constitutes the outer peripheral surface of the armature core 8, and the peripheral wall portion 32 faces the permanent magnet 7.

By providing the teeth 12 radially on the outer periphery of the core body 11, 18 dovetail slots 13 are formed between adjacent teeth 12. The slots 13 extend along the axial direction, and a plurality of slots 13 are formed at equal pitches along the circumferential direction.
The windings 14 covered with enamel are inserted between the slots 13, and a plurality of windings 14 are wound through an insulator (not shown) that is an insulating material covered with the winding body 31 of the teeth 12. . The plurality of windings 14 form a plurality of armature coils 9 on the outer periphery of the armature core 8.

  In the present embodiment, four permanent magnets 7 are provided (the number of magnetic poles is 4), so the number of pole pairs is 2, and 18 teeth 12 (slots 13) are provided. That is, the number of teeth 12 (slot 13) is set to 9 times (odd times) the number of pole pairs.

  A commutator 10 is externally fitted and fixed to the other end side of the armature core 8 of the rotating shaft 3. Eighteen segments 15 made of a conductive material are attached to the outer peripheral surface of the commutator 10. The segment 15 is made of a plate-shaped metal piece that is long in the axial direction, and is fixed in parallel at equal intervals along the circumferential direction while being insulated from each other. The outer diameter D1 of the commutator 10 is set in the range of 20 mm or more and 30 mm or less.

  A riser 16 is integrally formed at the end of each segment 15 on the armature core 8 side so as to be folded back to the outer diameter side. The riser 16 is wound around the winding start end and winding end of each winding forming the armature coil 9, and each winding 14 is electrically connected to the riser 16 by fusing or the like and mechanically. It is fixed. Thereby, each segment 15 and each coil | winding 14 corresponding to this are conduct | electrically_connected.

  Further, the risers 16 respectively corresponding to the segments 15 having the same potential, that is, the segments 15 facing each other around the rotation shaft 3 (in this embodiment, the segments 15 arranged with the eight segments 15 interposed therebetween). Each of the pressure equalizing lines 40 is wound around, and the pressure equalizing lines 40 are fixed to the riser 16 by fusing similarly to the winding start end and the winding end end of each winding 14 (FIGS. 5 and 6). reference). The pressure equalizing line 40 is for short-circuiting the segments 15 having the same potential, and is arranged so as to be wound around the rotating shaft 3 between the commutator 10 and the armature core 8.

  The commutator 10 configured in this way is in a state of facing the gear housing 23 of the speed reduction mechanism 4. The gear housing 23 is formed by a housing main body 42 that is formed in a substantially box shape having an opening 42 a on one surface and accommodates the gear group 41 of the speed reduction mechanism 4, and a cover 43 that closes the opening 42 a of the housing main body 42. Yes. On the side of the electric motor 2 of the housing main body 42, a brush housing portion 22 is formed, and the commutator 10 of the electric motor 2 is exposed here.

As shown in FIGS. 2 to 4, the brush housing portion 22 is formed in a concave shape on the side of the electric motor 2 of the gear housing 23. The peripheral wall 30 of the brush housing part 22 is formed in a substantially oval cross section, and is composed of a flat wall 30a and an arc wall 30b.
A cover 33 formed in a cylindrical shape having a substantially oval cross section is provided inside the brush housing portion 22 so as to correspond to the inside. The cover 33 also has a flat wall 33a and an arc wall 33b. Further, a holder stay 34 formed so as to correspond to the cover 33 is provided inside the cover 33. The holder stay 34 is fastened and fixed to the side wall 42 b of the housing body 42 by bolts 35.

  The holder stay 34 is provided with brush holders 36 at three locations in the circumferential direction. In the brush holder 36, the brushes 21 are housed in such a manner that they can be moved in and out in a state where the brushes 21 are urged through the springs S, respectively. Since the tips of the brushes 21 are urged by the springs S, they are in sliding contact with the segments 15 of the commutator 10, and current from an external power source (not shown) is supplied to the commutator 10 via the brushes 21. .

  The brush 21 includes a low-speed brush (first brush) 21a and a high-speed brush (second brush) 21b that are selectively connected to the anode side, and these low-speed brush (first brush) 21a or It is configured by a common brush (third brush) 21c that is used in common with any one of the high-speed brushes (second brush) 21b and connected to the cathode side.

  The low speed brush 21a and the common brush 21c are disposed at an electrical angle of 180 °, that is, at a mechanical angle of 90 ° in the circumferential direction. On the other hand, the high speed brush 21b is spaced apart from the low speed brush 21a by an angle obtained by adding α degrees to 180 degrees in the circumferential direction. In this embodiment, the common brush 21c is described as the cathode side, and the low speed brush 21a and the high speed brush 21b are described as the anode side. However, the anode side and the cathode side may be reversed.

  Here, since the segments 15 having the same potential of the commutator 10, that is, the segments 15 facing each other around the rotation shaft 3 are short-circuited by the pressure equalizing line 40, the segments where the brush 21 is not in sliding contact are also included. Power can be supplied. Therefore, the high speed brush 21b exists at a position advanced by the angle α with respect to the low speed brush 21a. In this embodiment, the angle α is set to 29 degrees. Here, it is needless to say that the angle α is not limited to 29 degrees, and may be any angle from 27 degrees to 33 degrees.

  Thus, the armature coil formed between the high-speed brush (second brush) 21b and the common brush (third brush) 21c by setting the angle α to 29 degrees and not making the value larger than necessary. The electrical resistance of 9 can be made larger than a certain value. Thus, by setting the electric resistance to a value larger than a certain level, the current value of the current flowing through the high-speed brush 21b can be prevented from becoming larger than necessary, and the current value of the current flowing excessively when the electric motor 2 is locked. Can be suppressed.

  In this way, by arranging the brushes 21a to 21c, in the cover 33 and the holder stay 34, portions where the brushes 21a to 21c do not exist can be cut off. That is, the cover 33 can be formed in a substantially oval cross section, and the low speed brush 21a and the common brush 21c can be disposed in the vicinity of the connection portion between the flat wall 33a and the arc wall 33b.

  On the other hand, the low speed brush 21a and the common brush 21c of the cover 33 are arranged at positions adjacent to the one arc wall 33b, whereas the high speed brush 21b is arranged with the low speed brush 21a and the common brush 21c. The one arc wall 33b is arranged at a position adjacent to the other arc wall 33b on the opposite side with the rotation axis 3 as the center. For this reason, the brush storage part 22 can be formed in a substantially oval cross section, and the brush storage part 22 can be flattened.

  Further, as shown in detail in FIG. 3, the brush widths W1 in the circumferential direction of the low speed brush 21a and the common brush 21c are set to be substantially the same. On the other hand, the brush width W2 in the circumferential direction of the high speed brush 21b is set smaller than the brush width W1 of the low speed brush 21a. Specifically, when the outer diameter of the commutator 10 is set in the range of 20 mm or more and 30 mm or less, the brush width W1 of the low speed brush 21a and the common brush 21c is in the range of 2.5 mm or more and 5 mm or less. Is set. On the other hand, the brush width W2 of the high speed brush 21b is set in a range of 1.5 mm or more and smaller than 2.5 mm.

  Thus, by setting the brush width W1 of the low speed brush 21a and the common brush 21c and the brush width W2 of the high speed brush 21b, the low speed brush 21a and the high speed brush 21b are simultaneously slid on the same segment 15. It is possible to avoid contact.

  That is, the pressure equalizing line 40 connected to the commutator 10, for example, means that the low speed brush 21a is also present at a point-symmetrical position about the rotating shaft 3 (see the two-dot chain line in FIG. 3). ). In this case, the interval between the low speed brush 21a and the high speed brush 21b is substantially the same as the interval between the adjacent segments 15 and 15. However, since the brush width W2 of the high-speed brush 21b is set smaller than the brush width W1 of the low-speed brush 21a, the low-speed brush 21a and the high-speed brush 21b are prevented from sliding simultaneously on the same segment 15. can do.

  The same can be said for the high-speed brush 21b and the common brush 21c. In other words, the high-speed brush 21 b is also present at a point-symmetrical position about the rotation shaft 3 by the pressure equalizing line 40 connected to the commutator 10. However, since the brush width W2 of the high-speed brush 21b is set to be smaller than the brush width W1 of the common brush 21c, the high-speed brush 21b and the common brush 21c are prevented from simultaneously sliding on the same segment 15. be able to.

  In the electric motor of the present embodiment, the high-speed brush 21b is disposed at a position separated from the low-speed brush 21a by an advance angle α in order to cause a large rotational speed difference. Therefore, when the high-speed brush 21b is selectively energized, the internal resistance of the electric circuit formed in the armature coil 9 between the high-speed brush 21b and the common brush 21c decreases. Therefore, it is assumed that the current value of the current supplied from the high-speed brush to the electric motor increases excessively, and in particular, the lock current generated when the electric motor is locked by an external load becomes excessive.

  In this regard, in the electric motor of the present embodiment, the conductive material (first conductive material) mainly composed of carbon powder forming the high-speed brush 21b is carbon powder forming the low-speed brush 21a and the common brush 21c. A conductive material having a high electrical resistance is used for the conductive material (second conductive material) as a main component. As described above, since the conductive material (first conductive material) mainly composed of carbon powder forming the high-speed brush 21b has a high resistance, when the high-speed brush 21b is selectively energized, the high-speed brush The internal resistance of the electric circuit formed in the armature coil 9 between 21b and the common brush 21c can be increased. Therefore, an object is to prevent an excessive increase in the value of the current flowing through the electric motor 2 when the high-speed brush 21b is selectively energized.

  As described above, in this embodiment, the conductive material (first conductive material) of the high-speed brush 21b is electrically resistant to the conductive material (second conductive material) of the low-speed brush 21a and the common brush 21c. A highly conductive material is used. However, the present invention is not limited to this. For example, the conductive material of the low-speed brush 21a may have a high resistance like the conductive material (first conductive material) of the high-speed brush 21b. By doing so, it is possible to prevent the current value of the current flowing through the electric motor 2 from excessively increasing even when the low speed brush 21a is selectively energized.

  As shown in FIGS. 1 and 2, the gear group 41 accommodated in the housing body 42 of the gear housing 23 meshes with the worm shaft 25 and the worm shaft 25 integrally connected to the rotating shaft 3 of the electric motor 2. A stepped gear 26 and a spar gear 27 that meshes with the stepped gear 26 are configured. One end of the worm shaft 25 is connected to the rotating shaft 3, and the other end is rotatably supported by the housing body 42. The stepped gear 26 is formed by integrally forming a worm wheel 28 that meshes with the worm shaft 25 and a small-diameter gear 29 that has a smaller diameter than the worm wheel 28.

  An end 61 a of an idler shaft 61 is press-fitted and fixed to the housing main body 42. A stepped gear 26 is rotatably supported on the idler shaft 61.

  The spur gear 27 meshes with the small diameter gear 29 of the stepped gear 26. At the center of the spur gear 27 in the radial direction, a boss portion 65 is formed to protrude toward the cover 43 side. The boss 65 is in contact with the cover 43 so as to be rotatable. An output shaft 62 is press-fitted into the boss portion 65. The output shaft 62 protrudes from the bottom wall (end portion) 42 c of the housing body 42. On the bottom wall 42c of the housing main body 42, a boss portion 63 is formed projecting outward at a portion corresponding to the output shaft 62. The boss portion 63 is provided with a sliding bearing 64 for rotatably supporting the output shaft 62.

  A portion of the output shaft 62 that protrudes from the housing main body 42 is formed with a tapered portion 66 that gradually tapers toward the tip. A serration 67 is formed in the tapered portion 66. Thereby, for example, an external mechanism for driving a wiper or the like and the output shaft 62 can be connected.

  In addition, a connector 68 projects from the side wall 42 b of the housing body 42 along the axial direction of the rotary shaft 3. The connector 68 is for supplying a current from an external power source to the electric motor 2. A connection terminal 70 is provided in the receiving port 69 of the connector 68, and the connection terminal 70 is electrically connected to the brush 21 (21 a to 21 c) of the electric motor 2. As a result, current from an external power supply is supplied to the commutator 10 via the brush 21.

Further, a bolt seat 71 for fastening and fixing the cover 43 is integrally formed at the opening edge of the housing body 42. The cover 43 is integrally formed with a mounting seat 73 having a bolt hole (not shown) through which the bolt 72 can be inserted at a portion corresponding to the bolt seat 71 of the housing main body 42. The cover 43 is configured to be fastened and fixed to the housing main body 42 by inserting bolts 72 into the mounting seat 73 and screwing the bolts 72 into the bolt seat 71 of the housing main body 42.
Further, the cover 43 is provided with a power distribution board 74 for electrically connecting the connection terminal 70 of the connector 68 and the brush 21 of the electric motor 2. A pattern (not shown) having a role of a lead wire is formed on the power distribution board 74.

  Based on FIG. 5 and FIG. 6, a winding structure of a plurality of windings 14 constituting the armature coil 9 wound around the armature core 8 will be described. 5 and 6 are development views of the armature 6, and a gap between adjacent teeth 12 corresponds to the slot 13. In the following drawings, each segment 15 and each tooth 12 will be described with reference numerals.

  The armature coil 9 is composed of first and second conducting wires 101 and 102, and the first and second conducting wires 101 and 102 are wound around the armature core 8 by a double flyer system in which the opposing faces are 180 degrees, An armature coil 9 is formed. In the present embodiment, one nine windings 14 are wound around the armature core 8 by the first conducting wire 101, and the other nine windings 14 are wound around the armature core 8 by the second conducting wire 102. The armature coil 9 is formed by a total of 18 windings 14. Here, the equalizing wire 40 is also formed in series with the windings 14 by the first and second conducting wires 101 and 102 described above.

  FIG. 5 shows a winding 14 that is first wound around the armature core 8 among the windings 14 that are wound around the armature core 8 by the first conductor 101 in the double flyer system. Hereinafter, the winding 14 formed first by the first conductive wire 101 will be described with reference to FIG.

  Winding 14 is integrated from coil winding 81 wound around tooth 14, winding start portion 82 and winding end portion 83 formed at both ends of coil winding 81, and winding start portion 82 and winding end portion 83. The first and second connection lines 84 and 85 extend continuously.

  The coil winding 81 includes a first coil winding 81a wound around the first to fourth teeth 12 adjacent to each other and wound in the forward direction, and 4 wound with the first coil winding 81a. The second coil winding 81b is disposed adjacent to one tooth and wound in the opposite direction so as to surround the fifth to eighth teeth adjacent to each other. Here, the first coil winding 81a and the second coil winding 81b are connected in series.

  The first connection line 84 is connected to the riser 16 of the twelfth segment 15. On the other hand, the second connection line 85 is routed in the circumferential direction opposite to the first connection line 84 and connected to the riser 16 of the eleventh segment 15.

  Next, the winding process of the first conducting wire 101 around the armature core 8 and the commutator 10 will be described. First, the end portion 101 a of the first conducting wire 101 is entangled with the riser 16 of the third segment 15. Then, it is routed in the direction of the second segment 15 and is entangled with the riser 16 of the twelfth segment 115 arranged at the point of contrast with the third segment 15. At this time, a pressure equalizing line 40 is formed by the first conducting wire 101 from the third segment 15 to the twelfth segment 15.

  Thereafter, the first conductive wire 101 is routed between the twelfth segment 15 and the eighteenth and first teeth 12, and is wound around the first to fourth teeth 12 in the forward direction to be wound around the first winding. After forming the line portion 81a, the second winding portion 81b is formed by being wound in the reverse direction around the fifth to eighth teeth 12. The first conducting wire 101 is entangled with the riser 16 of the eleventh segment 11. This is a step of winding one equalizing wire 40 and one winding 14 around the armature core 8 and the commutator 10 with the first conductive wire 101. By repeating this step nine times in succession, The winding process of the lead wire 101 to the armature core 8 and the commutator 10 is completed, and nine windings 14 and nine connecting wires are wound or arranged on the armature core 8 and the commutator 10 by the first lead wire 101. The

  FIG. 6 shows the winding 14 first wound around the armature core 8 among the windings 14 wound around the armature core 8 by the second conductor 102 by the double flyer method. Hereinafter, the winding 14 formed by the second conductive wire 102 will be described with reference to FIG.

  Winding 14 is integrated from coil winding 81 wound around tooth 14, winding start portion 82 and winding end portion 83 formed at both ends of coil winding 81, and winding start portion 82 and winding end portion 83. The first and second connection lines 84 and 85 extend continuously.

  The coil winding 81 includes a first coil winding 81a wound in the forward direction around the tenth to thirteenth teeth 12 adjacent to each other, and a first coil winding 81a wound around the coil winding 81. The second coil winding 81b is disposed adjacent to one tooth and wound around the fourteenth to seventeenth teeth 12 adjacent to each other and wound in the opposite direction. Here, the first coil winding 81a and the second coil winding 81b are connected in series.

  The first connection line 84 is connected to the riser 16 of the third segment 15. On the other hand, the second connection line 85 is arranged in the circumferential direction opposite to the first connection line 84 and connected to the riser 16 of the second segment 15.

  Next, a process of winding the second conductive wire 102 around the armature core 8 and the commutator 10 will be described. First, the end 102 a of the second conducting wire 102 is entangled with the riser 16 of the twelfth segment 15. Then, it is routed in the direction of the eleventh segment 15 and is entangled with the riser 16 of the third segment 115 arranged in a point contrast position with respect to the twelfth segment 15. At this time, a pressure equalizing line 40 is formed by the second conducting wire 102 from the twelfth segment 15 to the third segment 15.

  Thereafter, the first conductive wire 101 is routed between the eighteenth and first teeth 12 from the third segment 15, wound around the tenth to thirteenth teeth 12 and wound in the forward direction. After forming the line portion 81a, the second winding portion 81b is formed by surrounding the fourteenth to seventeenth teeth 12 and winding in the reverse direction. The second conductive wire 102 is entangled with the riser 16 of the second segment 11. This is a step of winding one equalizing wire 40 and one winding 14 around the armature core 8 and the commutator 10 with the second conductive wire 102. By repeating this step nine times, The winding process of the conductor 102 to the armature core 8 and the commutator 10 is completed, and the nine conductors 14 and the nine connection wires are wound around the armature core 8 and the commutator 10 by the second conductor 102.

  Next, based on FIG.7 and FIG.8, the relative position of the permanent magnet 7 and the brush 21 of the electric motor 2 of this embodiment is demonstrated. Here, FIG. 7 is a cross-sectional view of the electric motor 2 showing the relative positions of the permanent magnet 7 and the brush 21. On the other hand, FIG. 8 is a development view of the electric motor 2 showing the relative positions of the permanent magnet 7 and the brush 21.

  7 and 8, any one of the plurality of windings 14 </ b> A is connected to the 11th and 12th segments 15 and 15. In these drawings, the boundary portion 15a of the 11th and 12th segments 15, 15 is located at the center (circumferential center) L5 of the low speed brush (first brush) 21a and the radial direction of the rotating shaft. The state in which the armature 6 is rotationally arranged so as to be in sliding contact at a substantially coincident position is shown.

  In such a state, the first coil winding 81a of the winding 14A and the magnet 7a, which is any one of the four magnets 7, face each other at a position where they overlap in the radial direction. Two magnets 7 are fixedly arranged in a cylindrical portion (housing) 53. Specifically, the circumferential center L1 of the first coil winding 81a of the winding 14A and the circumferential center L3 of the magnet 7a, which is any one of the magnets, are opposed to positions where they overlap each other in the radial direction. In addition, four magnets 7 are fixedly arranged in the cylindrical portion (housing) 53 at an equal pitch.

  In the embodiment of the present invention, the relative angle β1 between the circumferential center L1 of the first coil winding 81a of the winding 14A and the circumferential center L3 of the magnet 7a is set to 0 degree. Needless to say, the relative angle β1 may be within a range of plus or minus 2 degrees. The eleventh and twelfth segments 15 and 15 are also connected to the winding 14B via pressure equalizing wires 40 and 40, and the same is true for the relative positional relationship between the winding 14B and the magnet 7c. I can say.

  Here, the common brush (third brush) 21c is arranged at a position that is 90 degrees apart from the low speed brush (first brush) 21a. On the other hand, the four magnets 7 are disposed in the cylindrical portion (housing) 53 at an equal pitch of a mechanical angle of 90 degrees. Therefore, the above applies similarly between the common brush (third brush) 21 c and any one of the four magnets 7.

  That is, the boundary 15a between the segments 15 and 15 to which any one of the windings 14 is connected is substantially the center (circumferential center) L6 of the common brush (third brush) 21c and the radial direction of the rotation shaft. When the armature 6 is rotationally arranged so as to be in sliding contact with the matching position, the first coil winding 81a of any one of the windings 14 and any one of the four magnets 7 are used. The four magnets 7 are fixedly arranged in the cylindrical portion (housing) 53 so as to face a certain magnet 7 at a position overlapping in the radial direction.

(Arranged so that the magnet of the first coil winding overlaps in the radial direction ⇒ The boundary where the winding is connected and the brush match)
In the above, the arrangement position of the magnet 7 has been described with reference to the arrangement position of the low speed brush (first brush) 21a or the common brush (third brush) 21c. Next, the relative positions of the permanent magnet 7 and the brush 21 are described by explaining the arrangement position of the low speed brush (first brush) 21a or the common brush (third brush) 21c with reference to the arrangement position of the magnet 7. The positional relationship will be described.

  7 and 8, the first coil winding 81a of any one of the windings 14A and the magnet 7a, which is any one of the four magnets 7, have a diameter. The state where the armature 6 is rotationally arranged so as to face the position overlapping in the direction is shown. Specifically, the armature 6 is rotationally arranged in a state where the circumferential center L1 of the first coil winding 81a of the winding 14A and the circumferential center L3 of the magnet 7a are opposed to each other in the radial direction. ing.

  In such a state, the circumferential center L5 of the low speed brush (first brush) 21a and the boundary 15a of the eleventh and twelfth segments 15, 15 to which the winding 14A is connected rotate. A low speed brush (first brush) 21a is fixedly arranged so as to be substantially coincident in the radial direction of the shaft.

  In the embodiment of the present invention, the relative angle β2 between the circumferential center L5 of the low speed brush (first brush) 21a and the boundary portion 15a of the eleventh and twelfth segments 15 and 15 is set to 0 degree. However, it goes without saying that the angle is not limited to 0 degrees, and the relative angle β2 only needs to be within a range of plus or minus 2 degrees.

  Here, the winding 14B is wound around the armature core 8 at a position 180 degrees apart from the winding 14A by the double flyer method, and the eleventh and twelfth through the equalizing wires 40, 40. Connected to segments 15 and 15. Therefore, the circumferential center L4 of the magnet 7c disposed at a position 180 degrees away from the magnet 7a and the circumferential center L2 of the first coil winding 81a of the winding 14B are mutually in the radial direction. The same can be said when the armature 6 is rotationally arranged in a state of facing the overlapping position.

  That is, even in such a state, the circumferential center L5 of the low speed brush (first brush) 21a and the boundary portion 15a of the eleventh and twelfth segments 15, 15 to which the winding 14A is connected However, it can be said that the low-speed brush (first brush) 21a is fixedly arranged so as to be substantially coincident with the radial direction of the rotation shaft.

  Here, the common brush (third brush) 21c is arranged at a position that is 90 degrees apart from the low speed brush (first brush) 21a. On the other hand, the four magnets 7 are disposed in the cylindrical portion (housing) 53 at an equal pitch of a mechanical angle of 90 degrees. Therefore, the above applies similarly between the common brush (third brush) 21 c and any one of the four magnets 7.

  That is, the armature 6 is arranged so that the first coil winding 81a of any one of the windings 14 and the magnet 7 that is one of the four magnets 7 are opposed to each other at a position where they overlap in the radial direction. When rotated, the boundary 15a of the segments 15, 15 to which any one of the windings 14 is connected is the center (circumferential center) L6 of the common brush (third brush) 21c and the rotation axis. The common brush (third brush) 21c is rotationally arranged so as to be in sliding contact with a position that substantially matches in the radial direction.

  As shown in FIGS. 7 and 8, the relative positional relationship between the brush 21 and the permanent magnet 7 is that the brush 21 or the magnet 7 is used in order to reduce the armature reaction that occurs in the electric motor 2 and improve the motor efficiency. This is because the relative position is adjusted and the advance angle is set in the electric motor 2. The contents will be described below.

  The advance angle of the electric motor 2 can be set by adjusting the arrangement position of either the brush 21 or the magnet 7. Hereinafter, based on FIG.9 and FIG.10, while showing the arrangement position of the magnet 7 with respect to the magnet 7 when it is assumed that there is no influence of an armature reaction, the brush for low speeds (1st brush) 21a with respect to the magnet 7 is shown. It is shown that the advance angle is set for the electric motor 2 of the present embodiment by appropriately moving and adjusting the common brush (third brush) 21c.

  9 and 10 show the neutral position of the brush 21 with respect to the magnet 7 when the influence of the armature reaction is not taken into consideration. 9 is a cross-sectional view of the electric motor 2 showing the relative position of the permanent magnet 7 and the brush 21, and FIG. 10 is a development view of the electric motor 2 showing the relative position of the permanent magnet 7 and the brush 21. is there.

  9 and 10, the first coil winding 81a of the winding 14A is wound in the forward direction around the first to fourth teeth 12 adjacent to each other, and the second coil winding of the winding 14A is wound. The wire 81 b is wound in the opposite direction so as to surround the fifth tooth 12 to the eighth tooth 12 adjacent to the fourth tooth 12. The winding 14 </ b> A is connected to the risers 16 of the eleventh and twelfth segments 15 by first and second connection lines 84 and 85, respectively.

  At this time, the winding 14B wound around the position facing the winding 14A by the double flyer method is wound around the armature core 8 as follows. The first coil winding 81a of the winding 14B is wound in the forward direction around the tenth to thirteenth teeth 12 adjacent to each other, and the second coil winding 81b of the winding 14B is the thirteenth winding. The fourteenth teeth 12 adjacent to the teeth 12 are wound around the seventh teeth 12 in the reverse direction. The winding 14B is connected to the riser 16 of the second and third segments 15 by the first and second connection wires 84 and 85, respectively, and is connected to the winding 14A by the pressure equalizing wires 40 and 40. Similarly, the risers 16 of the eleventh and twelfth segments 15 are respectively connected.

  Here, FIGS. 9 and 10 show the armature 6 at a position where the circumferential center L9 of the slot 13b in which the conductors b and c of the winding 14A are disposed overlaps with the center LA between the magnets 7a and 7b in the radial direction. Shows a state in which the rotation is arranged. At this time, the circumferential center L11 of the slot 13e in which the conductors f and g of the winding 14B are arranged and the interpolar center LC of the magnets 7c and 7d overlap in the radial direction. Further, the circumferential center L12 of the 18th tooth 12 sandwiched between the conductor h of the winding 14B and the conductor a of the winding 14A and the center LD between the poles of the magnets 7d and 7a overlap in the radial direction. The circumferential center L10 of the ninth tooth 12 sandwiched between the conductor d of the wire 14A and the conductor e of the winding 14B and the interpolar center LB of the magnets 7b and 7c overlap in the radial direction.

  When the armature 6 is rotationally arranged as described above, the conductors b and c are arranged on the interpolar center LA, and the conductors f and g are arranged on the interpolar center LC. On the other hand, the conductor a and the conductor h are arranged in line-symmetrical positions with respect to the interpolar center LD, and the conductor d and the conductor e are arranged in line-symmetrical positions with respect to the interpolar center LB. Therefore, it can be said that the conductors a to h are arranged in line-symmetrical positions with respect to the interelectrode centers LA to LD, respectively.

  Thus, in the state where the armature 6 is rotationally arranged inside the electric motor 2, the low speed brush 21 a has a circumferential center L <b> 7 in the radial direction with the boundary portion 15 a of the eleventh and twelfth segments 15, 15. It is arranged at the overlapping position. Therefore, when the armature 6 is rotationally arranged at the position shown in FIGS. 9 and 10 due to the rotation of the armature 6, the low speed brush 21a slides over the eleventh and twelfth segments 15,15. As a result, the windings 14A and 14B are short-circuited by the low speed brush 21a, and no current is supplied to the windings 14A and 14B.

  In this case, as described above, the conductors a to h (conductors hatched in FIG. 9 and indicated by circles) arranged in line-symmetrical positions with respect to the interelectrode centers LA to LD, respectively. No current is supplied, and current is supplied to the other conductors (conductors indicated by white circles in FIG. 9). In such a state, if there is no distortion in the main magnetic field generated by the magnets 7a to 7b, the current is supplied and the conductor (effective conductor) intersecting with the main magnetic field is geometrically largest, so the motor efficiency Is the maximum. Therefore, when no current is supplied to the winding 14, that is, the position of the brush 21 shown in FIGS. 9 and 10 is a neutral position when the influence of the armature reaction is not considered.

  However, when a current is supplied to the winding 14, the distortion of the main magnetic field due to the field magnetomotive force generated by the winding 14 must be taken into consideration and the distortion must be reduced. In this embodiment, as shown in FIGS. 7 and 8, the advance angle of the mechanical angle φ is set in the rotational direction of the armature 6 with respect to the neutral position of the brush 21 shown in FIGS. The neutral position is adjusted. By setting the advance angle of the mechanical angle φ in this way, a current is supplied to the winding 14 and the distortion of the main magnetic field due to the field magnetomotive force generated by the winding 14 can be reduced. We are trying to improve. Here, in the present embodiment, the mechanical angle φ (advance angle) is set to 5 degrees. Needless to say, the mechanical angle φ (advance angle) is not limited to 5 degrees, and may be in the range of 3 degrees to 7 degrees.

It is a top view of the motor with a reduction gear in the embodiment of the present invention. It is a longitudinal cross-sectional view of the motor with a reduction gear in embodiment of this invention. It is a cross-sectional view of the electric motor in the embodiment of the present invention. FIG. 3 is a view as seen from an arrow A in FIG. 2. It is an expanded view of the armature which shows the coil | winding wound by the 1st conducting wire in embodiment of this invention. It is an expanded view of the armature which shows the coil | winding wound by the 2nd conducting wire in embodiment of this invention. It is a cross-sectional view of the electric motor which shows the relative position of the brush and magnet in embodiment of this invention. It is an expanded view of the electric motor which shows the relative position of the brush and magnet in embodiment of this invention. It is a cross-sectional view of the electric motor showing the relative positions of the brush and the magnet when the armature reaction is not considered. It is an expanded view of the electric motor which shows the relative position of a brush and a magnet in the case where an armature reaction is not considered.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Motor with reduction gear 2 Electric motor 3 Rotating shaft 4 Reduction mechanism 5 Yoke 6 Armature 7 Permanent magnet (magnetic pole)
8 Armature core 9 Armature coil (coil)
10 Commutator 12 Teeth 13 Slot 14 Winding (coil)
15 segment 15a boundary 16 riser 21 brush 21a low speed brush 21b high speed brush 21c common brush 25 worm shaft 28 worm wheel 40 pressure equalization line (short circuit member)
81 Winding portion 82 Winding start portion 83 Winding end portion 84 First connecting wire 85 Second connecting wire 101 First conducting wire 102 Second conducting wire

Claims (10)

A housing that is a magnetic yoke;
Four magnets fixed at substantially equal pitch on the inner wall of the housing;
A rotary shaft, an armature core having a plurality of teeth radially formed and fixed on the rotary shaft, and a commutator having a plurality of segments fixed on the rotary shaft at a predetermined interval from the armature core An armature coil having a plurality of windings wound around the armature core, and a plurality of pressure equalizing lines connecting a pair of segments arranged at a mechanical angle of 180 degrees apart of the commutator, An armature disposed between the four magnets and rotatably supported by the housing;
An electric motor comprising a plurality of brushes slidably contactable with the commutator segment of the armature;
The number of teeth is 18, the number of segments is 18, the number of windings is 18,
The brush includes first and second brushes that are selectively connected to a first power supply terminal, and a third brush that is connected to a second power supply terminal. The mechanical angle is arranged at a position approximately 90 degrees away from the third brush, and the second brush is separated from the position at a mechanical angle of 180 degrees away from the first brush by a predetermined angle. Placed in position,
Each of the windings is connected in series to a first coil winding wound in a forward direction around four adjacent teeth of the armature core, and the first coil winding, A second coil winding disposed adjacent to the four teeth wound with one coil winding and wound in the opposite direction around the four adjacent teeth; The ends of the second coil windings are respectively connected to adjacent segments,
Any one of the windings is connected so that the boundary between adjacent segments and the center of the first brush are in sliding contact with each other at a position where they substantially coincide with each other in the radial direction of the rotating shaft. When the armature is rotationally arranged,
The four magnets are placed in the housing such that the first coil winding of any one of the windings and any one of the four magnets face each other in a radial direction. An electric motor characterized by being arranged. A housing that is a magnetic yoke;
Four magnets fixed at substantially equal pitch on the inner wall of the housing;
A rotary shaft, an armature core having a plurality of teeth radially formed and fixed on the rotary shaft, and a commutator having a plurality of segments fixed on the rotary shaft at a predetermined interval from the armature core An armature coil having a plurality of windings wound around the armature core, and a plurality of pressure equalizing lines connecting a pair of segments arranged at a mechanical angle of 180 degrees apart of the commutator, An armature disposed between the four magnets and rotatably supported by the housing;
An electric motor comprising a plurality of brushes slidably contactable with the commutator segment of the armature;
The number of teeth is 18, the number of segments is 18, the number of windings is 18,
The brush includes first and second brushes that are selectively connected to a first power supply terminal, and a third brush that is connected to a second power supply terminal. The mechanical angle is arranged at a position approximately 90 degrees away from the third brush, and the second brush is separated from the position at a mechanical angle of 180 degrees away from the first brush by a predetermined angle. Placed in position,
Each of the windings is connected in series to a first coil winding wound in a forward direction around four adjacent teeth of the armature core, and the first coil winding, A second coil winding disposed adjacent to the four teeth wound with one coil winding and wound in the opposite direction around the four adjacent teeth; The ends of the second coil windings are respectively connected to adjacent segments,
Any one of the windings is connected so that the boundary between adjacent segments and the center of the third brush are in sliding contact with each other at a position where they substantially coincide with each other in the radial direction of the rotating shaft. When the armature is rotationally arranged,
The four magnets are placed in the housing such that the first coil winding of any one of the windings and any one of the four magnets face each other in a radial direction. The electric motor according to claim 1, wherein the electric motor is arranged.   The four magnets are arranged such that the circumferential center of the first coil winding of the one winding and the circumferential center of the one magnet substantially overlap each other in the radial direction. The electric motor according to claim 1, wherein the electric motor is disposed in the housing.   The second brush is disposed at a position where the mechanical angle is greater than 27 degrees and less than or equal to 33 degrees with respect to the first brush from a position where the mechanical angle is 180 degrees apart. 4. The electric motor according to any one of 3.   The first conductive material forming the second brush is a conductive material having a higher electric resistance than the second conductive material forming the first and second brushes. The electric motor according to any one of claims 1 to 4. A housing that is a magnetic yoke;
Four magnets fixed at substantially equal pitch on the inner wall of the housing;
A rotary shaft, an armature core having a plurality of teeth radially formed and fixed on the rotary shaft, and a commutator having a plurality of segments fixed on the rotary shaft at a predetermined interval from the armature core An armature coil having a plurality of windings wound around the armature core, and a plurality of pressure equalizing lines connecting a pair of segments arranged at a mechanical angle of 180 degrees apart of the commutator, An armature disposed between the four magnets and rotatably supported by the housing;
An electric motor comprising a plurality of brushes slidably contactable with the commutator segment of the armature;
The number of teeth is 18, the number of segments is 18, the number of windings is 18, and the brush is selectively connected to a first power supply terminal. A brush and a third brush connected to a second power supply terminal, wherein the first brush is disposed at a mechanical angle of about 90 degrees with respect to the third brush; The second brush is disposed at a position away from the position where the mechanical angle is 180 degrees away from the first brush by a predetermined angle.
Each of the windings is connected in series to a first coil winding wound in a forward direction around four adjacent teeth of the armature core, and the first coil winding, A second coil winding disposed adjacent to the four teeth wound with one coil winding and wound in the opposite direction around the four adjacent teeth; The ends of the second coil windings are respectively connected to adjacent segments,
The armature is rotationally disposed so that the first coil winding of any one of the windings and any one of the four magnets face each other in a radial overlap position. When
The center of the first brush in the circumferential direction is connected to any one of the windings, and the boundary between adjacent segments is positioned substantially coincident with the radial direction of the rotating shaft. An electric motor, wherein one brush is disposed. A housing that is a magnetic yoke;
Four magnets fixed at substantially equal pitch on the inner wall of the housing;
A rotary shaft, an armature core having a plurality of teeth radially formed and fixed on the rotary shaft, and a commutator having a plurality of segments fixed on the rotary shaft at a predetermined interval from the armature core An armature coil having a plurality of windings wound around the armature core, and a plurality of pressure equalizing lines connecting a pair of segments arranged at a mechanical angle of 180 degrees apart of the commutator, An armature disposed between the four magnets and rotatably supported by the housing;
An electric motor comprising a plurality of brushes slidably contactable with the commutator segment of the armature;
The number of teeth is 18, the number of segments is 18, the number of windings is 18, and the brush is selectively connected to a first power supply terminal. A brush and a third brush connected to a second power supply terminal, wherein the first brush is disposed at a mechanical angle of about 90 degrees with respect to the third brush; The second brush is disposed at a position away from the position where the mechanical angle is 180 degrees away from the first brush by a predetermined angle.
Each of the windings is connected in series to a first coil winding wound in a forward direction around four adjacent teeth of the armature core, and the first coil winding, A second coil winding disposed adjacent to the four teeth wound with one coil winding and wound in the opposite direction around the four adjacent teeth; The ends of the second coil windings are respectively connected to adjacent segments,
The armature is rotationally disposed so that the first coil winding of any one of the windings and any one of the four magnets face each other in a radial overlap position. When
The center of the third brush in the circumferential direction is connected to any one of the windings, and the boundary between adjacent segments is positioned substantially coincident with the radial direction of the rotating shaft. 3. An electric motor characterized in that three brushes are arranged.   The four magnets are arranged such that the circumferential center of the first coil winding of the one winding and the circumferential center of the one magnet substantially overlap each other in the radial direction. The electric motor according to claim 6, wherein the electric motor is disposed in the housing.   The second brush is disposed at a mechanical angle of 29 degrees or more and 33 degrees or less from a position where the mechanical angle is 180 degrees away from the first brush. The electric motor according to any one of 8. The first conductive material forming the second brush is a conductive material having a higher electric resistance than the second conductive material forming the first and second brushes. The electric motor according to any one of Items 6 to 9.

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