JP2011010458A - Dc motor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a DC motor including a commutator capable of dealing with supply of a large current in a configuration with a rotor including a field disposed inside an armature.SOLUTION: The rotor 41 disposed inside the armature 21 includes a rotating shaft 42 and a rotor core 43 fixed to the rotating shaft 42. Slip rings 63, 64 connected to a power supply are disposed at one side in an axial direction of the rotor core 43, and the commutator 31 is disposed at the other side, where the commutator includes a plurality of segments 32 that are juxtaposed in a peripheral direction and to which an armature coil 23 of the armature 21 is connected and a connection line 33 for mutually and electrically connecting the segments 32 separated in a peripheral direction. A composite brush 50 is held by a brush holder 46, disposed inside the rotor core 43 and is placed in slide contact with the slip rings 63, 64 and the commutator 31 from an axial direction. Also, the composite brush 50 is directly or relatively pressed to the slip rings 63, 64 and the commutator 31 by a helical compression spring 66.

Description

  The present invention relates to a DC motor.

  Conventionally, there are DC motors in which a rotor having a field is arranged inside a cylindrical armature. For example, in the DC motor described in Patent Document 1, a commutator is disposed at a position facing an armature obtained by winding an armature coil around an armature core in the axial direction. The commutator is fixed to a housing case that holds the armature and has an annular plate shape, and its inner diameter and outer diameter are substantially equal to the inner diameter and outer diameter of the armature. This commutator is connected to a plurality of segments arranged side by side in the circumferential direction and a plurality of connections that are arranged on one end side in the axial direction of these segments and short-circuited between the segments in the circumferential direction so as to have the same potential The armature coil is connected to a plurality of segments. Further, a rotor is disposed inside the armature so as to be rotatable in the circumferential direction. A rotor core is fixed to the rotating shaft of the rotor via a cylindrical fixing member, and a plurality of magnets are embedded in the rotor core so that N poles and S poles are alternately arranged in the circumferential direction. Yes. In addition, a brush holder is fixed to the rotation shaft so as to be integrally rotatable, and the brush holder holds a plurality of power supply brushes and a plurality of rectifying brushes. Each of the plurality of power supply brushes is urged by a compression coil spring, so that it is fixed to the housing case and press-contacted to an annular slip ring connected to an external power supply device. Further, the plurality of rectifying brushes are urged by compression coil springs, respectively, so as to be in slidable contact with the commutator segments.

  In the DC motor described in Patent Document 1 as described above, when current is supplied to the armature through the slip ring, the power supply brush, the rectifying brush, and the commutator, the rotor is rotated with respect to the armature. At the same time, since the brush holder rotates with the rotation of the rotor, the segments that are in sliding contact with the rectifying brush are sequentially replaced, and the armature coils are sequentially rectified.

International Publication No. 2006/025444 Pamphlet

  In recent years, the direct current motor as described above has been desired to have a high output of the motor, and therefore, it is desired to supply a large current to the direct current motor. In order to supply a large current to the DC motor, the commutator needs to have a structure that can handle the large current. In order to obtain a commutator having a structure capable of handling a large current, it is conceivable to increase the cross-sectional area of the connection line (that is, the cross-sectional area in the direction orthogonal to the direction in which the current flows) by increasing the connection line. However, simply thickening the connection line increases the size of the commutator. And since many parts, such as a plurality of power supply brushes, a plurality of rectifying brushes, and a plurality of compression coil springs, are housed inside the housing case, the space for arranging the commutator inside the housing case is limited. Therefore, when the connecting wire is simply thickened and the cross-sectional area of the connecting wire is increased, there is a problem that the DC motor is increased in size.

  The present invention has been made in view of such circumstances, and an object of the present invention is to provide a commutator capable of supplying a large current in a configuration in which a rotor having a field is arranged inside an armature. It is to provide a direct current motor.

  In order to solve the above-described problem, an invention according to claim 1 includes an annular armature having a plurality of armature coils, a rotating shaft disposed inside the armature, a rotor core fixed to the rotating shaft, and A rotor having a field held by the rotor core, a slip ring to which a current is supplied, a plurality of segments arranged in parallel in the circumferential direction and electrically connected to the armature coil, and in the circumferential direction A commutator having a connection line for electrically connecting the segments at separate positions, a plurality of power supply brushes slidably contacting the slip ring from the axial direction, and an axial direction while being electrically connected to the power supply brush A plurality of commutating brushes that are in sliding contact with the commutator, and current is supplied to the armature through the slip ring, the power supply brush, the commutating brush, and the commutator. A flow motor, wherein the power supply brush and the rectifying brush are integrated with each other to form a composite brush, a brush holder disposed inside the rotor core to hold the composite brush, and the composite brush to the slip ring and The gist of the invention is that it comprises pressing means for directly or relatively pressing the commutator.

  According to this configuration, since the power supply brush and the rectifying brush are integrated into a composite brush, the number of brushes provided for supplying power to the armature is reduced. Furthermore, since the power supply brush and the rectifying brush are integrated into a composite brush, the pressing means for pressing the power supply brush against the slip ring and the pressing means for pressing the rectifying brush against the commutator as in the past. May not be arranged. Therefore, the number of pressing means can be reduced. As described above, since the number of components arranged in the DC motor is reduced, the space for arranging the commutator in the DC motor can be expanded without increasing the size of the DC motor. And since the commutator can be enlarged by the amount of space expansion, the connecting line can be thickened to increase the cross-sectional area of the connecting line (that is, the cross-sectional area perpendicular to the direction in which the current flows). It becomes possible. Therefore, the commutator can be adapted to supply a large current. Further, since the number of parts is reduced, the direct current motor can be easily assembled, and the productivity of the direct current motor can be improved.

  According to a second aspect of the present invention, in the DC motor according to the first aspect, the plurality of composite brushes are directly or relatively pressed against the slip ring and the commutator by the one pressing unit. Is the gist.

  According to this configuration, since the plurality of composite brushes are pressed directly or relatively against the slip ring and the commutator with one pressing means, the number of parts is further reduced. Therefore, the direct current motor can be assembled more easily.

  According to a third aspect of the present invention, in the DC motor according to the first or second aspect, the slip ring is provided as a pair of an anode side slip ring and a cathode side slip ring, and the composite brush is 2 The one composite brush is directly or relatively pressed against the slip ring on the anode side and simultaneously contacts a plurality of the segments located in the circumferential direction, and the other composite brush The gist thereof is to simultaneously contact the plurality of segments that are pressed directly or relatively against the slip ring on the cathode side and are spaced apart in the circumferential direction.

  According to this configuration, since the number of composite brushes is minimized, the number of parts is further reduced. In addition, since each composite brush is in contact with a plurality of segments at the same time, it is easy to cope with a large current.

  According to a fourth aspect of the present invention, in the motor according to any one of the first to third aspects, the commutator is disposed on one axial side of the rotor core, and the axial direction of the rotor core. The slip ring is disposed on the other side of the slip ring, and one of the slip ring and the commutator is biased in the axial direction by one pressing means. The gist is to urge a plurality of the composite brushes toward the center.

  According to this configuration, since the pressing means urges one of the slip ring and the commutator in the axial direction, even if only one, a plurality of composite brushes are simultaneously applied to the slip ring and the commutator. It can be biased towards either one. And since there is only one pressing means, the number of parts is reduced.

  According to a fifth aspect of the present invention, in the DC motor according to the first aspect, the commutator is disposed on one axial side of the rotor core, and the slip ring is disposed on the other axial side of the rotor core. The composite brush is configured such that the power supply brush and the rectifying brush are connected by a conductive wire, and the pressing means is disposed along the conductive wire between the power supply brush and the rectifying brush in each composite brush. The gist of the invention is a compression coil spring that is arranged and biases the power supply brush and the rectifying brush toward both sides in the axial direction.

  According to this configuration, in each composite brush, both the power supply brush and the rectifying brush are urged in the axial direction by the compression coil spring disposed between the power supply brush and the rectifying brush. Therefore, it is not necessary to provide a compression coil spring that presses the power supply brush in the axial direction and a compression coil spring that presses the rectifying brush in the axial direction as in the prior art, so the number of compression coil springs is reduced.

  According to a sixth aspect of the present invention, in the DC motor according to any one of the first to fifth aspects of the present invention, the field magnets are arranged in a circumferential direction so that N poles and S poles are alternately arranged in the circumferential direction. The composite brush has a rectifying side sliding contact portion that is in sliding contact with the commutator, and the rectifying side sliding contact portion extends in a radial direction through a central portion in a circumferential direction of the field magnet. Its gist is that it is arranged on the center line of the magnetism.

  According to this configuration, the magnetic flux flows from the central portion in the circumferential direction of the field toward the central portion in the circumferential direction of the adjacent field. Therefore, by arranging the rectifying side sliding contact portion where rectification is performed and the direction of the current is switched on the center line of the field, it is possible to suppress generation of useless magnetic flux that does not contribute to generation of torque.

  ADVANTAGE OF THE INVENTION According to this invention, the direct current motor provided with the commutator which can respond to supply of a large electric current by the structure by which the rotor which has a field is arrange | positioned inside an armature can be provided.

The schematic block diagram of the direct-current motor of 1st Embodiment. Sectional drawing of the direct-current motor of 1st Embodiment. The expanded sectional view of a commutator. (A) And (b) is an expansion perspective view of the composite brush of 1st Embodiment. The expansion perspective view of the composite brush of 2nd Embodiment. The schematic block diagram of the DC motor of 2nd Embodiment. Sectional drawing of the DC motor of 2nd Embodiment. The schematic block diagram of the direct-current motor of 3rd Embodiment. Sectional drawing of the DC motor of 3rd Embodiment. (A) And (b) is an expansion perspective view of the composite brush of 3rd Embodiment.

(First embodiment)
Hereinafter, a first embodiment of the present invention will be described with reference to the drawings.
FIG. 1 is a schematic configuration diagram of a DC motor according to the first embodiment. As shown in FIG. 1, a housing case 10 that is an outer shell of a DC motor is composed of first and second cases 11 and 12 that are divided into two in the axial direction.

  The first case 11 located on the left side in FIG. 1 has a cylindrical first support portion 11a and a first end portion in the axial direction of the first support portion 11a (the left end portion in FIG. 1). 1 closed portion 11b and has a substantially bottomed cylindrical shape. In addition, the second case 12 located on the right side in FIG. 1 includes a cylindrical second support portion 12a having the same outer diameter and inner diameter as the first support portion 11a, and the second support portion 12a. It is comprised from the 1st case 11 and the 2nd obstruction | occlusion part 12b which obstruct | occludes the edge part of the axial direction on the opposite side, and has comprised the bottomed cylindrical shape. The first and second support steps 11c are formed by expanding the inner diameters of the first and second support portions 11a and 12a in the opening portions of the first and second cases 11 and 12 facing each other. , 12c are formed. The first case 11 and the second case 12 are connected and fixed to each other by screws (not shown) penetrating in the axial direction.

  The first case 11 and the second case 12 support a substantially annular armature 21 sandwiched from both sides in the axial direction, and the armature 21 is attached to a substantially annular armature core 22. It is formed by winding an armature coil 23. As shown in FIG. 2, the armature core 22 is made of a metal magnetic material, and has a cylindrical yoke portion 22a provided on the outer peripheral side, and extends radially inward from the inner peripheral surface of the yoke portion 22a. It is comprised from the book teeth 22b. The outer diameter of the armature core 22 is larger than the inner diameters of the first and second support portions 11a and 12a and smaller than the outer diameters of the first and second support portions 11a and 12a. . The plurality of armature cores 22 are wound around the armature core 22 so as to pass through a space between adjacent teeth 22b in the circumferential direction, and end portions of the armature coil 23 at the start and end of winding. Is pulled out to one end side (second closing portion 12b side) of the armature core 22 in the axial direction (see FIG. 1).

  As shown in FIG. 1, such an armature 21 has both end portions in the axial direction of the yoke portion 22 a at the first support step portion 11 c of the first case 11 and the second case 12 of the second case 12. It is supported by the first and second cases 12 in a state of being engaged with the support step portion 12c.

  A commutator 31 is integrally fixed to the axial end of the armature 21 on the second closing portion 12b side by a resin mold. The commutator 31 includes 36 segments 32 arranged side by side in the circumferential direction, and 36 connection lines 33 that short-circuit the segments 32 located at positions separated in the circumferential direction. In FIG. 1, only two of the 36 segments 32 are illustrated, and only two of the 36 connection lines 33 are illustrated.

  As shown in FIG. 3, each segment 32 made of a conductive metal material has a wider width in the circumferential direction as the shape seen from the axial direction goes from the radially inner end to the radially outer end. A plate-shaped segment main body 32a having a sector shape, an outer peripheral side connection portion 32b projecting in a thickness direction of the segment main body 32a from a radially outer end of the segment main body 32a, and a radially inner side of the segment main body 32a The outer peripheral side connection part 32b and the inner peripheral side connection part 32c projecting in the same direction are integrally formed from the end part. Each segment 32 is substantially U-shaped when viewed from the circumferential direction. Further, in each segment 32, the end surface of the segment body 32a opposite to the outer peripheral side connection portion 32b and the inner peripheral side connection portion 32c (that is, the end surface on the back side in FIG. 3) is a flat slidable contact surface 32d (FIG. 1). See).

  The 36 segments 32 are arranged side by side in the circumferential direction so that their sliding contact surfaces 32d are arranged in the same plane orthogonal to the axial direction of the armature 21, and the segments 32 adjacent to each other in the circumferential direction. A gap is provided between them so that they are not in contact with each other. As shown in FIG. 1, the 36 segments 32 have sliding contact surfaces 32 d on one end side in the axial direction of the armature 21, that is, on the side opposite to the second closing portion 12 b of the second case 12. It is arranged to face. Furthermore, the outer diameters of the 36 segments 32 arranged side by side in the circumferential direction are substantially equal to the inner diameter of the armature 21, and the inner diameter of the segment 32 is slightly larger than the outer diameter of the rotating shaft 42 described later. Yes. For the 36 segments 32 arranged in parallel in the circumferential direction, the 36 connecting lines 33 are arranged between the outer peripheral side connecting portion 32b and the inner peripheral side connecting portion 32c.

  As shown in FIG. 3, each connection line 33 is formed by bending a strip-shaped copper plate in the thickness direction and bending both end portions in the longitudinal direction. Note that the connection line 33 may be formed of a conductive wire. The 36 connecting lines 33 are arranged such that the thickness direction is along the circumferential direction, and the axial direction and the short direction are coincident. In addition, the radially outer end of the connection line 33 is connected to the outer peripheral side connection part 32 b of the segment 32 by welding or the like, and the radially inner end of the connection line 33 is the diameter of the connection line 33. It is connected by welding or the like to the inner peripheral side connection portion 32c of the segment 32 located 90 ° counterclockwise from the segment 32 to which the outer end of the direction is connected. In this way, each connection line 33 electrically connects the segments 32 located at 90 ° apart in the circumferential direction (short-circuited to the same potential).

  As shown in FIGS. 1 and 3, the end portions 23a of the armature coil 23 are connected to the outer peripheral side connection portions 32b of nine pairs of segments 32 adjacent to each other in the circumferential direction and a total of 18 segments 32. Each is connected by welding or the like. Note that the end of the armature coil 23 is between the pair of segments 32 to which the end 23a of the armature coil 23 is connected and another pair of segments 32 to which the end 23a of the armature coil 23 is connected. Two segments 32 that are not directly connected to each other are interposed.

  As shown in FIG. 1, the mold resin 34 for molding the armature 21 and the commutator 31 (that is, the 36 segments 32 and the 36 connecting wires 33) is made of an insulating resin material, and the radial direction of the teeth 22b. The armature 21 and the commutator 31 are integrated by exposing the distal end surface of the opposite side and the outer peripheral surface of the yoke portion 22a and exposing the sliding contact surface 32d of the segment 32. The mold resin 34 is interposed between the segments 32 adjacent to each other in the circumferential direction to insulate the segments 32 adjacent to each other in the circumferential direction and is adjacent to each other in the circumferential direction between the connection lines 33 adjacent to each other in the circumferential direction. A short circuit between the connecting wires 33 is suppressed. Further, the mold resin 34 is also interposed in an axial gap between the segment 32 and the connection line 33, and the segment 32 and the connection line 33 are formed at a portion other than a joint portion between the segment 32 and the connection line 33 by welding. Suppressing short circuit due to contact.

  A rotor 41 is disposed inside the armature 21 so as to be rotatable in the circumferential direction. The rotor 41 includes a rotating shaft 42 disposed in the radial center of the DC motor, a rotor core 43 fixed to the rotating shaft 42, and eight magnets (fixed to the outer peripheral surface of the rotor core 43). Field) 44.

  A columnar rotating shaft 42 is provided at the radial center of the first closing portion 11b and at the radial center of the second closing portion 12b and is opposed to the bearing 45a. Both ends in the axial direction are pivotally supported by the bearing 45b. The rotating shaft 42 passes through the central portion of the commutator 31 in the radial direction, and the inner diameter of the commutator 31 is set to be slightly larger than the outer diameter of the rotating shaft 42. The rotor core 43 is fixed at a position near the second closing portion 12b on the rotating shaft 42.

  As shown in FIG. 2, the rotor core 43 has a cylindrical shape in which the shape seen from the axial direction is a regular octagon. A fixing hole 43a penetrating the rotor core 43 in the axial direction is formed in the central portion of the rotor core 43 in the radial direction, and the rotor shaft 43 is press-fitted into the fixing hole 43a. Thus, the rotation shaft 42 is fixed. In addition, a rectangular plate-like magnet 44 is fixed to each of the eight planes constituting the outer peripheral surface of the rotor core 43, and the N magnets and the S poles are alternately arranged in the circumferential direction. It arrange | positions with respect to the rotor core 43 so that it may become. The eight magnets 44 are arranged at equiangular intervals (that is, 45 ° intervals) in the circumferential direction, and the radially outer side surface corresponds to the inner circumferential surface of the armature core 22 (that is, the tip surface of the teeth 22b). Each has an arc shape and faces the armature 21 in the radial direction.

  The rotor core 43 is formed with receiving holes 43b at eight positions that are equiangularly spaced in the circumferential direction. The accommodation holes 43b are formed corresponding to the circumferential positions of the eight magnets 44, and the center line L1 extending in the radial direction through the center in the circumferential direction of each accommodation hole 43b is the circumferential direction of each magnet 44. Coincides with a center line L2 extending in the radial direction through the center. And each accommodation hole 43b penetrates the rotor core 43 to an axial direction (refer FIG. 1), and the cross-sectional shape cut along the direction orthogonal to an axial direction goes to a radial direction outer side from radial inner side. It has a substantially fan shape with a wider width in the circumferential direction. In addition, an engagement recess 43c that is recessed toward the radially outer side is formed in the central portion in the circumferential direction on the radially inner side surface of the accommodation hole 43b. The engaging recess 43c extends along the axial direction, and has a rectangular cross-sectional shape cut along a direction orthogonal to the axial direction.

  As shown in FIGS. 1 and 2, a brush holder 46 is accommodated in each accommodation hole 43b. Each brush holder 46 is made of an insulating resin material and has a cylindrical shape corresponding to the inner peripheral surface of the accommodation hole 43b. That is, each brush holder 46 has a substantially fan shape in which the cross-sectional shape cut along the direction orthogonal to the axial direction has a generally fan-shaped width that increases from the radially inner side toward the radially outer side. On the radially outer side wall of the holder 46, a convex portion receiving portion 46a having a rectangular cross section is formed in a central portion in the circumferential direction so as to protrude radially outward. Further, the axial length of each brush holder 46 is formed to be equal to the axial length of the rotor core 43. The brush holders 46 are inserted into the receiving holes 43b from the axial direction, the outer peripheral surfaces thereof abut against the inner peripheral surfaces of the receiving holes 43b, and the convex portion receiving portions 46a are disposed in the engaging concave portions 43c. .

  Each brush holder 46 accommodates a composite brush 50 having conductivity. In this embodiment, out of a total of eight composite brushes 50, every other four in the circumferential direction are composite brushes 51 on the anode side, and the remaining four are composite brushes 52 on the cathode side.

  FIG. 4A is a perspective view of the composite brush 51 on the anode side. In FIGS. 4A and 4B, the axial direction, the radial direction, and the circumferential direction are directions when the composite brush 50 is disposed inside the DC motor. As shown in FIG. 4A, the columnar brush body 50a has a shape corresponding to the inside of the brush holder 46 (see FIG. 2), and is a cross-sectional shape cut along a direction orthogonal to the axial direction. Is formed in a fan shape, and an engaging convex portion 50b that protrudes radially outward is integrally formed at the center portion in the circumferential direction on the side surface on the radially outer side. The brush body 50a is formed such that the axial length thereof is shorter than the axial length of the brush holder 46, and the engaging protrusion 50b extends from one end of the brush body 50a to the other end along the axial direction. It extends to.

  Further, a straightening-side sliding contact portion 50c is integrally formed on one end surface in the axial direction of the brush body portion 50a (the right end surface in FIG. 4A). The rectifying side sliding contact portion 50c is a portion closer to the radially outer side on one end face in the axial direction of the brush body portion 50a and a central portion in the circumferential direction and one end portion in the axial direction of the engaging convex portion 50b (see FIG. 4 (a) protrudes along the axial direction from the right end, and has a rectangular parallelepiped shape. The circumferential width of the rectifying side sliding contact portion 50c is set to a width that does not straddle the three segments 32 (see FIG. 3) arranged in the circumferential direction at the same time.

  Further, a first power supply side sliding contact portion 50d is integrally formed on the other end surface in the axial direction of the brush main body portion 50a (the left end surface in FIG. 4A). The first power supply side sliding contact portion 50d protrudes along the axial direction from the radially inner end of the other end surface in the axial direction of the brush body portion 50a, and the shape viewed from the axial direction is from the radially inner side. It has a trapezoidal shape whose width in the circumferential direction increases as it goes radially outward.

  The length of the composite brush 51 on the anode side in the axial direction, that is, the length from the front end surface of the rectifying side sliding contact portion 50c to the front end surface of the first power supply side sliding contact portion 50d is the axis of the brush holder 46. It is formed longer than the length in the direction (see FIG. 1).

  FIG. 4B is a perspective view of the composite brush 52 on the cathode side. The composite brush 52 on the cathode side, like the composite brush 51 on the anode side, has a brush body 50a, an engaging convex portion 50b, and a rectifying side sliding contact portion 50c. And the 2nd electric power feeding side sliding contact part 50e is integrally formed in the other end surface (left end surface in FIG.4 (b)) of the axial direction in the brush main-body part 50a. The second power supply side sliding contact portion 50e protrudes along the axial direction from the radially outer end of the other axial end surface of the brush body 50a. The length in the axial direction of the cathode-side composite brush 52, that is, the length from the front end surface of the rectifying side sliding contact portion 50 c to the front end surface of the second power supply side sliding contact portion 50 e is the anode-side composite brush 51. Is longer than the axial length of the brush holder 46 (see FIG. 1).

  As shown in FIGS. 1 and 2, the anode-side composite brush 51 and the cathode-side composite brush 52 are arranged on the brush holder 46 from the axial direction so that the engaging convex portion 50b is disposed in the convex portion accommodating portion 46a. The rectifying side sliding contact portion 50c and the first and second power feeding side sliding contact portions 50d and 50e protrude from the both sides of the rotor core 43 in the axial direction through the rotor core 43 inserted in the axial direction. At the same time, the tip surface of the rectifying side sliding contact portion 50c comes into contact with the sliding contact surface 32d of the commutator 31 from the axial direction. Thus, each composite brush 50 is arranged inside the rotor core 43 by being arranged in the brush holder 46 arranged in the accommodation hole 43 b formed in the rotor core 43. Further, in the eight composite brushes 50 accommodated in the brush holder 46, the four first power supply side sliding contact portions 50d are positioned on the outer peripheral side with respect to the four second power supply side sliding contact portions 50e. Further, the eight rectifying side sliding contact portions 50c are arranged at equiangular intervals (that is, 45 ° intervals) in the circumferential direction, and the radial distance from the rotating shaft 42 in each rectifying side sliding contact portion 50c is equal. It has become. Further, the center line L3 extending in the radial direction through the center in the circumferential direction of each rectifying side sliding contact portion 50c coincides with the center line L2 of each magnet 44.

  As shown in FIG. 1, an annular guide member 61 is fixed to the inner surface of the first closing portion 11 b so as to be coaxial with the rotation shaft 42, and on the inner side of the guide member 61, A slip ring holder 62 is arranged. The slip ring holder 62 is made of an insulating resin material, and has a cylindrical guided portion 62a and one end in the axial direction of the guided portion 62a (the axial end on the rotor core 43 side, which is the right side in FIG. And an annular fixed holding portion 62b provided so as to be substantially closed.

  The guided portion 62 a is disposed on the inner side of the guide member 61 so as to be coaxial with the rotation shaft 42, and the outer diameter thereof is formed substantially equal to the inner diameter of the guide member 61, along the inner peripheral surface of the guide member 61. Can be moved in the axial direction.

  A pair of slip rings 63 and 64 are fixed to the outer surface of the fixed holding portion 62b (that is, the surface facing the rotor core 43 in the axial direction). That is, the DC motor of this embodiment has a configuration in which the commutator 31 is disposed on one side of the rotor core 43 in the axial direction, and slip rings 63 and 64 on the other side in the axial direction are disposed.

  The pair of slip rings 63 and 64 have an annular shape with different diameters, and are arranged concentrically around the rotation shaft 42. Moreover, the end surface of the axial direction by the side of the rotor core 43 in each slip ring 63, 64 has comprised the planar shape orthogonal to an axial direction. In this embodiment, the slip ring 63 on the inner peripheral side is a slip ring on the anode side, and the slip ring 64 on the outer peripheral side is a slip ring on the cathode side. Each of the slip rings 63 and 64 is connected to a power supply line 65 drawn out of the DC motor through the fixed holding portion 62 b and the guide member 61, and an external power source is connected via the power supply line 65. Current is supplied from the device.

  The pair of slip rings 63 and 64 are in contact with the end surfaces of the first and second power supply side sliding contact portions 50d and 50e of the composite brush 50 on the end surfaces in the axial direction on the rotor core 43 side. . Specifically, the tip surface of the first power supply side sliding contact portion 50d of the anode-side composite brush 51 facing in the axial direction is brought into contact with the slip ring 63 on the inner peripheral side from the axial direction, and on the outer peripheral side. The tip surface of the second power supply side sliding contact portion 50e of the cathode-side composite brush 52 facing the axial direction is in contact with the slip ring 64 from the axial direction. That is, the pair of slip rings 63 and 64 are arranged such that the composite brush 50 is interposed between the commutator 31 and the pair of slip rings 63 and 64.

  Further, one compression coil spring 66 (pressing means) is disposed inside the guided portion 62a and between the fixed holding portion 62b and the first closing portion 11b. The compression coil spring 66 has one end in the axial direction abutting on the inner surface of the first closing portion 11b on the outer periphery of the bearing 45a and the other end in the axial direction on the inner surface of the fixed holding portion 62b (ie, the first side) The slip ring holder 62 is urged toward the rotor core 43 along the axial direction. Due to the biasing force of the compression coil spring 66, the slip rings 63 and 64 together with the slip ring holder 62 are pressed toward the composite brush 50, and the composite brush 50 pressed against the slip rings 63 and 64 is further rectified along the axial direction. It is urged toward the child 31 and is pressed against the commutator 31. In other words, the composite brush 50 is relatively pressed against the slip rings 63 and 64 by the urging force of the compression coil spring 66 and directly pressed against the commutator 31.

  In the direct current motor configured as described above, the current supplied to the slip rings 63 and 64 from the external power supply device via the power supply line 65 is the first and second power supply side sliding contact portions 50d of the composite brush 50. , 50e through the brush body 50a to the rectifying side sliding contact portion 50c, and further supplied to the armature coil 23 directly or through the connection line 33 from the segment 32 in contact with the rectifying side sliding contact portion 50c. Then, a magnetic field is generated in the armature 21, and the rotor 41 rotates according to the magnetic field. As the rotor 41 rotates, the composite brush 50 rotates together with the rotor core 43, so that in the commutator 31, the segments 32 with which the commutation side sliding contact portion 50c comes into contact are sequentially switched, thereby sequentially commutating the armature coil 23. And the rotating shaft 42 is continuously rotated.

As described above, according to the first embodiment, the following operational effects can be achieved.
(1) Since the power supply brush and the rectifying brush are integrated into the composite brush 50 (51, 52), the number of brushes provided for supplying power to the armature 21 is reduced. Further, since the power supply brush and the rectifying brush are integrated into the composite brush 50, a compression coil spring for pressing the power supply brush against the slip ring and a rectifying brush for pressing the rectifier brush against the commutator as in the past. It is not necessary to arrange the compression coil springs. Therefore, the number of compression coil springs that bias the brush can be reduced. As described above, since the number of components arranged in the DC motor is reduced, the space for arranging the commutator 31 in the DC motor can be expanded without increasing the size of the DC motor. Since the commutator 31 can be enlarged by an amount corresponding to the increased space, the connecting wire 33 is thickened to increase the cross-sectional area of the connecting wire 33 (ie, the cross-sectional area perpendicular to the direction in which the current flows). It becomes possible to do. Therefore, the commutator 31 can be adapted to supply a large current. In addition, since the structure of the DC motor, which has been complicated in the past due to the large number of parts, has been simplified by reducing the number of parts, the assembly of the DC motor is improved. As a result, the direct current motor can be easily assembled, and the productivity of the direct current motor can be improved.

  (2) Since the eight composite brushes 50 are directly or relatively pressed against the slip rings 63 and 64 and the commutator 31 by one compression coil spring 66, the compression coil spring 66 that biases the composite brush 50 is used. The number is minimal. Therefore, the direct current motor can be assembled more easily.

  (3) Since only one compression coil spring 66 biases the slip rings 63 and 64 in the axial direction by biasing the slip ring holder 62 holding the slip rings 63 and 64, even if only one compression coil spring 66 is used. The eight composite brushes 50 in contact with the slip rings 63 and 64 can be simultaneously urged toward the commutator 31. Since only one compression coil spring 66 is provided, it is possible to contribute to a reduction in the number of parts.

  (4) The center line L1 of the rectifying side sliding contact portion 50c coincides with the center line L2 of the magnet 44, respectively. That is, the rectifying side sliding contact portion 50 c is disposed on the center line L <b> 2 of the magnet 44. In general, the magnetic flux of the magnet 44 flows from the central portion in the circumferential direction of the magnet 44 toward the central portion in the circumferential direction of the adjacent magnet 44. Therefore, by arranging the rectifying side sliding contact portion 50c where rectification is performed and the direction of the current is switched on the center line L2 of the magnet 44, it is possible to suppress generation of useless magnetic flux that does not contribute to generation of torque. Can do.

  (5) The armature 21 and the commutator 31 are molded and integrated with the mold resin 34. Therefore, when the DC motor is assembled, the armature 21 and the commutator 31 can be handled as one integrated part. Therefore, the number of parts is reduced, and the DC motor can be more easily assembled. Further, since the commutator 31 is integrated with the armature 21 by the mold resin 34, the second case 12 that accommodates the commutator 31 is suppressed from being complicated to hold the commutator 31. The

(Second Embodiment)
Hereinafter, a second embodiment of the present invention will be described with reference to the drawings. In the present embodiment, the same components as those in the first embodiment are denoted by the same reference numerals, and the description thereof is omitted.

  FIG. 6 is a schematic configuration diagram of a DC motor according to the second embodiment. A rotor 71 disposed inside the armature 21 includes a rotation shaft 72 disposed at a central portion in the radial direction of the DC motor, a rotor core 73 fixed to the rotation shaft 72, and an outer peripheral surface of the rotor core 73. Eight magnets 44 fixed thereto are provided.

  The columnar rotating shaft 72 is disposed through the radial center of the commutator 31 inside the DC motor, and both ends in the axial direction are pivotally supported by bearings 45a and 45b. Then, serrations are formed on the outer peripheral surface at a portion closer to the second closing portion 12b than the central portion in the axial direction of the rotating shaft 72, and the portions where the serrations are formed are connected via the brush holder 74. The rotor core 73 is fixed.

  The brush holder 74 made of an insulating resin material has a substantially cylindrical shape, and has a coupling hole 74a penetrating in the axial direction at a central portion in the radial direction. Then, by inserting the rotary shaft 72 into the coupling hole 74a, the brush holder 74 is serrated with the portion of the rotary shaft 72 where the serration is formed, and can rotate integrally with the rotary shaft 72. It is fixed. Further, as shown in FIG. 7, on the outer peripheral surface of the brush holder 74, engagement convex portions 74b projecting radially outward are formed at eight locations that are equiangularly spaced in the circumferential direction (that is, 45 ° intervals). At the same time, each engaging projection 74b extends from one end of the brush holder 74 in the axial direction to the other end along the axial direction. In addition, each engagement convex portion 74b has a rectangular cross-sectional shape cut along a direction orthogonal to the axial direction.

  The rotor core 73 has a cylindrical shape with a regular octagonal shape when viewed from the axial direction, and the axial length thereof is longer than the axial length of the brush holder 74 (see FIG. 6). ). The magnets 44 are fixed to the eight planes constituting the outer peripheral surface of the rotor core 73 so that the N pole and the S pole are alternately arranged in the circumferential direction. In addition, the housing hole 73a penetrating the central portion in the radial direction of the rotor core 73 in the axial direction has a circular cross section, and the inner diameter thereof is equal to the outer diameter of the brush holder 74 excluding the engaging convex portion 74b. Yes. Further, in the inner peripheral surface of the accommodation hole 73a, there are eight locations that are equiangularly spaced in the circumferential direction, and are recessed toward the radially outer side at eight locations that correspond to the circumferential center of each magnet 44. An engaging recess 73b is formed. These engagement concave portions 73b are formed corresponding to the eight engagement convex portions 74b formed on the outer peripheral surface of the brush holder 74, extend along the axial direction, and extend in a direction perpendicular to the axial direction. The cross-sectional shape cut along is a rectangular shape.

  Then, the rotor core 73 is fitted and fixed to the brush holder 74 by inserting the brush holder 74 into the receiving hole 73a so that the engaging convex portions 74b are inserted into the respective engaging concave portions 73b. . That is, the brush holder 74 is accommodated inside the rotor core 73. Further, as shown in FIG. 6, the axial end surface of the rotor core 73 facing the commutator 31 and the axial end surface of the brush holder 74 facing the commutator 31 are arranged in the same plane perpendicular to the axial direction. Has been. And in the accommodation hole 73a of the rotor core 73, the space S is formed between the brush holder 74 and the axial end surface of the rotor core 73 opposite to the commutator 31.

  As shown in FIGS. 6 and 7, the brush holder 74 is formed with holding holes 74c penetrating in the axial direction at eight positions that are equiangularly spaced in the circumferential direction. Each holding hole 74 c is formed at eight locations corresponding to the central portion in the circumferential direction of each magnet 44 at a portion near the outer peripheral edge of the brush holder 74. In the present embodiment, the radial distance from the rotation shaft 72 in each holding hole 74c is equal to the radial distance from the rotation shaft 72 in the anode side slip ring 64. Each holding hole 74c has a rectangular shape that is long in the radial direction when viewed from the axial direction, and the center line L4 that extends in the radial direction through the center in the circumferential direction of each holding hole 74c is the center line of the magnet 44. It matches L2. The circumferential width of each holding hole 74c is set to a width that does not straddle the three segments 32 (see FIG. 3) arranged in the circumferential direction at the same time. Such a brush holder 74 holds two composite brushes 81 and 82.

  FIG. 5 is a perspective view of the two composite brushes 81 and 82, showing a half cut in the diametrical direction. And the positional relationship of the composite brush 81 and the composite brush 82 in FIG. 5 is equal to the positional relationship when arrange | positioning inside a DC motor. The composite brushes 81 and 82 are both conductive. The anode-side composite brush 81 disposed on the inner peripheral side includes a cylindrical first power supply side sliding contact portion 81a and four first rectifying side sliding contact portions 81b extending from the power supply side sliding contact portion 81a. It is composed of As shown in FIG. 6, the first power feeding side sliding contact portion 81a has a cylindrical shape having an inner diameter and an outer diameter substantially equal to the inner diameter and the outer diameter of the anode side slip ring 63, and the first power feeding side sliding portion 81a. The axial length of the contact portion 81 a is set to a length that allows the first power supply side sliding contact portion 81 a to be accommodated in the space S between the brush holder 74 and the slip ring 63. Note that, in the first power supply side sliding contact portion 81a, the axial end surface opposite to the first rectifying side sliding contact portion 81b is in contact with the first contact surface 81c that is pressed against the anode side slip ring 63. Become.

  As shown in FIG. 5 to FIG. 7, the four first rectifying side sliding contact portions 81 b are formed in four holding holes 74 c that are alternately arranged in the circumferential direction among the eight holding holes 74 c provided in the brush holder 74. Correspondingly formed. Specifically, the four first rectifying side sliding contact portions 81b are equiangularly spaced in the circumferential direction (that is, the right end portion in FIG. 7) in the axial direction of the first power feeding side sliding contact portion 81a (that is, the right end portion in FIG. 7). 90 ° intervals). And each 1st rectification | straightening side sliding contact part 81b was extended in the radial direction outer side along the radial direction from the axial one end part (right end part in FIG. 7) of the 1st electric power feeding side sliding contact part 81a. Later, it extends along the axial direction to the side opposite to the first contact surface 81c (that is, the right side in FIG. 7). Further, each first rectifying side sliding contact portion 81b is a length from the axial end surface of the first power feeding side sliding contact portion 81a on the side where the first rectifying side sliding contact portion 81b is provided to the tip end surface thereof. Is longer than the length of the brush holder 74 in the axial direction. Further, the portion extending in the axial direction in each first rectifying side sliding contact portion 81b has a radial distance from the radial center of the composite brush 81 from the radial center of the brush holder 74 in the holding hole 74c. Equal to the radial distance of. Further, the portion extending in the axial direction in each first rectifying side sliding contact portion 81b has a cross-sectional shape orthogonal to the longitudinal direction (same as the axial direction) in the same manner as the shape of the holding hole 74c viewed from the axial direction. The front end surfaces of the four first rectifying side sliding contact portions 81b are located in the same plane orthogonal to the axial direction. The outer diameter of the composite brush 81 on the anode side (that is, the diameter of a circle passing through the radially outer side surface of the four first rectifying side sliding contact portions 81b) is substantially equal to the outer diameter of the slip ring 64 on the cathode side. The diameters of the circles passing through the radially inner side surfaces of the four first rectifying side sliding contact portions 81 b are substantially equal to the inner diameter of the slip ring 64. The axial length of the composite brush 81 is longer than the axial length of the rotor core 73.

  The cathode-side composite brush 82 disposed on the outer peripheral side includes a cylindrical second power supply side sliding contact portion 82a and four second rectifying side sliding contact portions 82b extending from the power supply side sliding contact portion 82a. It is configured. The second power supply side sliding contact portion 82a has a cylindrical shape having an inner diameter and an outer diameter substantially equal to the inner diameter and the outer diameter of the cathode side slip ring 64. The axial length of the second power supply side sliding contact portion 82a is equal to the first contact surface 81c of the first power supply side sliding contact portion 81a and the base end of the first rectifying side sliding contact portion 81b. The length is set to be shorter than the distance between the side end faces. Note that, in the second power supply side sliding contact portion 82a, the end surface in the axial direction opposite to the second rectifying side sliding contact portion 82b is in contact with the second contact surface 82c pressed against the slip ring 64 on the cathode side. Become.

  The four second rectifying side sliding contact portions 82b are arranged in the same manner as in the first rectifying side sliding contact portion 81b, but in the four holding holes 74c provided in the brush holder 74, every other four in the circumferential direction. It is formed corresponding to the holding hole 74c. More specifically, the four second rectifying side sliding contact portions 82b are arranged along the axial direction from the end surface in the axial direction opposite to the second contact surface 82c in the second power feeding side sliding contact portion 82a. It extends to the opposite side (ie, the right side in FIG. 7) from the contact surface 82c, and is formed at equiangular intervals (ie, 90 ° intervals) in the circumferential direction. Each of the second rectifying side sliding contact portions 82 b is formed such that the axial length is longer than the axial length of the brush holder 74. Further, each second straightening side sliding contact portion 82b has a radial distance from the radial center of the composite brush 82, and a radial distance from the radial center of the brush holder 74 in the holding hole 74c. equal. Further, each second straightening side sliding contact portion 82b has a rectangular shape whose cross-sectional shape orthogonal to the longitudinal direction (same as the axial direction) is long in the radial direction, similar to the shape of the holding hole 74c viewed from the axial direction. It has a shape. Further, the radial width of each second rectifying side sliding contact portion 82b is formed to be equal to the radial width of the second power feeding side sliding contact portion 82a. Further, the tip surfaces of the four second rectifying side sliding contact portions 82b are located in the same plane orthogonal to the axial direction, like the four first rectifying side sliding contact portions 81b. The outer diameter and inner diameter of the cathode composite brush 82 are substantially equal to the outer diameter and inner diameter of the cathode-side slip ring 64, and the length in the axial direction of the cathode-side composite brush 82 is the anode-side composite brush 81. Are formed equal to the length in the axial direction.

  The anode-side composite brush 81 as described above is arranged with respect to the brush holder 74 by inserting the four first rectifying-side sliding contact portions 81b into a total of four holding holes 74c every other one in the circumferential direction. Is done. In the composite brush 81 disposed with respect to the brush holder 74, the first power supply side sliding contact portion 81a is disposed in the space S, and the first power supply side sliding contact portion 81a is provided on the rotating shaft 72. And are arranged coaxially. Further, both ends of the composite brush 81 in the axial direction protrude in the axial direction from both ends of the rotor core 73 in the axial direction, and the first contact surface 81c of the first power supply side sliding contact portion 81a is the slip ring 63 on the anode side. The tip surfaces of the four first rectifying side sliding contact portions 81b are in contact with the sliding contact surface 32d of the commutator 31 from the axial direction. That is, the composite brush 81 simultaneously contacts the four segments 32 that are spaced by 90 ° in the circumferential direction at the first rectifying side sliding contact portion 81b.

  Similarly, the composite brush 82 on the cathode side is disposed with respect to the brush holder 74 by inserting the four second rectifying side sliding contact portions 82b into the remaining four holding holes 74c every other one in the circumferential direction. Is done. That is, the first rectifying side sliding contact portion 81b and the second rectifying side sliding contact portion 82b are alternately arranged in the circumferential direction. In the composite brush 82 disposed with respect to the brush holder 74, the second power supply side sliding contact portion 82a is disposed on the outer periphery of the first power supply side sliding contact portion 81a in the space S, and The second power supply side sliding contact portion 82 a is disposed concentrically with the first power supply side sliding contact portion 81 a around the rotation shaft 72. Further, both end portions of the composite brush 82 in the axial direction protrude in the axial direction from both ends of the rotor core 73 in the axial direction, and the second contact surface 82c of the second power supply side sliding contact portion 82a is the slip ring 64 on the cathode side. The tip surfaces of the four second rectifying side sliding contact portions 82b are in contact with the sliding contact surface 32d of the commutator 31 from the axial direction. That is, the composite brush 82 is simultaneously in contact with the four segments 32 that are spaced by 90 ° in the circumferential direction at the second rectifying side sliding contact portion 82b.

  As shown in FIG. 7, the first and second rectifying side sliding contact portions 81b and 82b inserted into the holding holes 74c have center lines L5 and L6 extending in the radial direction through the center in the circumferential direction. , And the center line L2 of each magnet 44 respectively. These composite brushes 81 can rotate together with the rotor core 73 as the rotary shaft 72 rotates.

  Further, as shown in FIG. 6, one compression coil spring 66 disposed inside the slip ring holder 62 biases the slip ring holder 62 toward the rotor core 73 along the axial direction. 66, the slip rings 63 and 64 together with the slip ring holder 62 are pressed against the composite brushes 81 and 82, and the composite brushes 81 and 82 pressed against the slip rings 63 and 64 are applied to the commutator 31 side. And is pressed against the commutator 31. That is, the composite brushes 81 and 82 are relatively pressed against the slip rings 63 and 64 and directly against the commutator 31 by the urging force of the compression coil spring 66.

  In the DC motor as described above, the current supplied from the external power supply device to the slip rings 63 and 64 via the power supply line 65 is supplied from the first and second power supply side sliding contact portions 81a and 82a to the first. And flows into the second rectifying side sliding contact portions 81b and 82b, and further from the segment 32 in contact with the first and second rectifying side sliding contact portions 81b and 82b to the armature coil 23 directly or through the connection line 33. Supplied. Then, a magnetic field is generated in the armature 21, and the rotor 71 rotates according to the magnetic field. As the rotor 71 rotates, the composite brushes 81 and 82 rotate together with the rotor core 73, so that in the commutator 31, the segments 32 that are in contact with the first and second rectifying side sliding contact portions 81b and 82b are sequentially switched. Thereby, the rectification of the armature coil 23 is sequentially performed, and the rotating shaft 72 is continuously rotated.

As described above, according to the second embodiment, in addition to the functions and effects (1) to (5) of the first embodiment, the following functions and effects can be achieved.
(6) The DC motor includes one composite brush 81 on the anode side and one composite brush 82 on the cathode side. That is, the number of composite brushes is minimized. Therefore, since the number of parts is further reduced, the assembling property is further improved and the productivity of the DC motor is improved. Moreover, since each composite brush 81 and 82 contacts the some segment 32 simultaneously, it is easy to respond also to a large current.

(Third embodiment)
Hereinafter, a third embodiment of the present invention will be described with reference to the drawings. In the present embodiment, the same components as those in the first embodiment are denoted by the same reference numerals, and the description thereof is omitted.

FIG. 8 is a schematic configuration diagram of a DC motor according to the third embodiment.
A substantially annular slip ring holder 101 is fixed inside the first case 11. A slip ring holder 101 made of an insulating resin material holds a pair of slip rings 63 and 64 at an end portion in the axial direction on the side opposite to the first closing portion 11b (that is, the inner side of the DC motor). The slip rings 63 and 64 are supplied with an electric current from an external power supply device through a power supply line 102 drawn out of the DC motor through the slip ring holder 101.

  A rotor 111 disposed inside the armature 21 includes a rotating shaft 42 disposed at the radial center of the DC motor, a rotor core 112 fixed to the rotating shaft 42, and an outer peripheral surface of the rotor core 112. Eight magnets 44 fixed thereto are provided.

  The rotor core 112 is fixed at a position near the second closing portion 12b on the rotation shaft. As shown in FIG. 9, the substantially cylindrical rotor core 112 has a regular octagonal shape when viewed from the axial direction, and the N plane and the S pole are formed on the eight planes constituting the outer peripheral surface of the rotor core 112. Magnets 44 are fixed to be alternately arranged in the circumferential direction. As shown in FIG. 8, at the axial end of the rotor core 112 on the side of the commutator 31, there are eight positioning portions 112 a that abut against the axial end surface of the magnet 44 on the side of the commutator 31. It extends toward the outer side in the radial direction, and the positioning of each magnet 44 in the axial direction with respect to the rotor core 112 is performed by the positioning portion 112a.

  The rotor core 112 is provided with a housing recess 112b that opens on the opposite side to the commutator 31 (that is, the left side in FIG. 8). The housing recess 112b is recessed from the end of the rotor core 112 in the axial direction opposite to the commutator 31 to the commutator 31 side along the axial direction, and the depth thereof is the length of the magnet 44 in the axial direction. The shape seen from the axial direction is substantially circular. In addition, a fixing hole 112c into which the rotary shaft 42 is inserted for fixing is formed in the center of the bottom of the housing recess 112b in the axial direction, and around the fixing hole 112c in the circumferential direction, etc. Insertion holes 112d are formed in eight positions corresponding to the central portions in the circumferential direction of the eight magnets 44 so as to penetrate in the axial direction at eight positions that are angular intervals (that is, 45 ° intervals). In FIG. 8, only two of the eight insertion holes 112d are shown. Further, as shown in FIG. 9, the inner circumferential surface of the accommodating recess 112b has eight locations that are equiangularly spaced in the circumferential direction (that is, 45 ° intervals), and is located at the center in the circumferential direction of the eight magnets 44. Engaging recesses 112e that are recessed toward the outside in the radial direction are formed at eight corresponding locations. Each engaging recess 112e extends from the opening of the housing recess 112b to the bottom along the axial direction, and has a rectangular cross-sectional shape cut along a direction perpendicular to the axial direction.

  A cylindrical brush holder 113 is housed in the housing recess 112b. The brush holder 113 is made of an insulating resin material, and the axial length of the brush holder 113 is formed to be equal to the depth of the housing recess 112b. In addition, on the outer peripheral surface of the brush holder 113, engagement convex portions 113a protruding outward in the radial direction are formed at eight positions that are equiangularly spaced (45 ° intervals) in the circumferential direction. These engaging convex portions 113a are formed corresponding to the eight engaging concave portions 112e formed on the inner peripheral surface of the accommodating concave portion 112b of the rotor core 112, and the axial direction of the brush holder 113 along the axial direction. In addition to extending from one end to the other end, the cross-sectional shape cut along a direction orthogonal to the axial direction forms a rectangular shape. In addition, a through hole 113b having a circular cross section penetrating in the axial direction is formed in the central portion of the brush holder 113 in the radial direction. The brush holder 113 is housed in the housing recess 112b with the rotating shaft 42 inserted through the through-hole 113b and the eight engaging projections 113a inserted into the eight engaging recesses 112e, respectively. Yes.

  Further, as shown in FIGS. 8 and 9, the axial end portions of the brush holder 113 facing the slip rings 63, 64 have eight positions that are equiangularly spaced (that is, 45 ° intervals) in the circumferential direction. The holding recesses 113c are recessed in the axial direction at eight locations corresponding to the central portions of the magnets 44 in the circumferential direction. The holding recess 113c has a fan shape in which the shape seen from the axial direction becomes wider in the circumferential direction from the radially inner side to the radially outer side, and the bottom surface of each holding recess 113c has A holding hole 113d that penetrates the brush holder 113 in the axial direction is formed at a position that is an end portion on the outer side in the radial direction and a central portion in the circumferential direction. The eight holding holes 113d have a trapezoidal shape in which the cross-sectional shape in the direction orthogonal to the axial direction becomes wider in the circumferential direction from the radially inner side to the radially outer side, and at the bottom of the housing recess 112b. The eight insertion holes 112d formed are arranged in the axial direction.

  The brush holder 113 as described above holds eight composite brushes 120. Of the eight composite brushes 120, four composite brushes 120 are anode-side composite brushes 121, and the remaining four composite brushes 120 are cathode-side composite brushes 122.

  As shown in FIG. 10A, the anode-side composite brush 121 includes a rectifying side sliding contact portion 120a, a first power feeding portion 120b, and the rectifying side sliding contact portion 120a and the first power feeding portion 120b. It is comprised from the conducting wire 120c which connects and integrates.

  The rectifying side sliding contact portion 120a has a shape corresponding to the holding hole 113d (see FIG. 9), a cross-sectional shape orthogonal to the longitudinal direction forms a trapezoidal columnar shape, and the rectifying side sliding contact portion 120a includes The holding hole 113d is shorter than the axial length (see FIG. 8).

  The first power feeding portion 120b includes a base 120d having a fan-like plate shape corresponding to the holding recess 113c (see FIG. 8), and a first power feeding side sliding contact portion 120e formed integrally with the base 120d. It is composed of The base portion 120d is connected to one end surface in the longitudinal direction of the rectifying side sliding contact portion 120a at one end surface in the thickness direction by a conducting wire 120c. The conducting wire 120c is bent in a hook shape and can be expanded and contracted in the longitudinal direction. Further, the first feeding side sliding contact portion 120e is the same as the radially inner end portion (see FIG. 8) of the other end surface in the thickness direction of the base portion 120d (that is, the end surface in the thickness direction opposite to the conductor 120c). It protrudes along the thickness direction of the base 120d. And the compression coil spring 123 is arrange | positioned along the conducting wire 120c between the rectification | straightening side sliding contact part 120a and the base 120d. The compression coil spring 123 is arranged so that the conducting wire 120c penetrates the inside thereof in the axial direction, that is, surrounds the outer periphery of the conducting wire 120c.

  As shown in FIG. 10B, the cathode-side composite brush 122 includes a rectifying side sliding contact portion 120a similar to the anode-side composite brush 121, a second power feeding portion 120f, and these rectifying side sliding contact portions 120a. And a conductive wire 120c that connects and integrates the second power feeding unit 120f.

  The second power feeding unit 120f includes a base part 120d similar to the first power feeding part 120b, and a second power feeding side sliding contact part 120g formed integrally with the base part 120d. That is, the cathode-side composite brush 122 is different from the anode-side composite brush 121 in the configuration of the power feeding side sliding contact portion. The second feeding-side sliding contact portion 120g has a base portion 120d from the radially outer end (see FIG. 8) on the other end surface in the thickness direction of the base portion 120d (that is, the end surface in the thickness direction opposite to the conductive wire 120c). Is formed so as to protrude along the thickness direction. Further, a compression coil spring 123 is disposed between the rectifying side sliding contact portion 120a and the base portion 120d so as to extend along the conducting wire 120c. The compression coil spring 123 is arranged so that the conducting wire 120c penetrates the inside thereof in the axial direction, that is, surrounds the outer periphery of the conducting wire 120c.

  As shown in FIGS. 8 and 9, the four composite brushes 121 on the anode side are accommodated in the four holding recesses 113 c and the holding holes 113 d that are alternately arranged in the circumferential direction in the brush holder 113. The four composite brushes 122 on the cathode side are accommodated in the remaining four holding recesses 113c and holding holes 113d. Specifically, the first and second power feeding portions 120b and 120f are accommodated in the holding recess 113c, respectively, and the rectifying side sliding contact portion 120a, the conductive wire 120c, and the compression coil spring 123 are respectively disposed in the holding holes 113d. Yes. And the one side end surface (end surface on the opposite side to the conducting wire 120c) of the longitudinal direction of each rectification | straightening side sliding contact part 120a contact | abuts to the sliding contact surface 32d of the commutator 31 from an axial direction, and each rectification | straightening side sliding contact part 120a A center line L7 that extends in the radial direction through the center in the circumferential direction coincides with the center line L2 of each magnet 44. Further, the front end surfaces of the four first power supply side sliding contact portions 120e are in contact with the slip ring 63 on the anode side from the axial direction, and the front end surfaces of the four second power supply side sliding contact portions 120g are respectively on the cathode side. Is in contact with the slip ring 64 from the axial direction.

  And the compression coil spring 123 arrange | positioned between the rectification | straightening side sliding contact part 120a and the 1st and 2nd electric power feeding parts 120b and 120f makes the rectification side sliding contact part 120a to the commutator 31 side along an axial direction. In addition to urging, the first and second power feeding portions 120f are urged toward the slip rings 63 and 64 along the axial direction, so that each rectifying side sliding contact portion 120a is caused by the urging force of the compression coil spring 123. Directly pressed by the commutator 31, the first and second feeding-side sliding contact portions 120 e and 120 g are pressed directly by the slip rings 63 and 64.

  In the DC motor configured as described above, the current supplied from the external power supply device to the slip rings 63 and 64 via the power supply line 102 is supplied from the first and second power supply side sliding contact portions 120e and 120g. The rectification side sliding contact portion 120a flows to the rectification side sliding contact portion 120a through the base portion 120d and the conducting wire 120c, and is further supplied to the armature coil 23 directly or through the connection line 33 from the segment 32 in contact with the rectification side sliding contact portion 120a. Then, a magnetic field is generated in the armature 21, and the rotor 111 rotates according to the magnetic field. Since the composite brushes 121 and 122 rotate together with the rotor core 112 as the rotor 111 rotates, the segments 32 with which the commutator 31 is brought into contact with the commutating side sliding contact portion 120a are sequentially switched. Is rectified, and the rotating shaft 42 is continuously rotated.

As described above, according to the third embodiment, the following operational effects can be achieved in addition to the operational effects of (1), (4), and (5) of the first embodiment.
(7) In each composite brush 120, the first and second power feeding units 120b, 120f are provided by the compression coil spring 123 disposed between the first and second power feeding units 120b, 120f and the rectifying side sliding contact part 120a. Both 120f and the rectifying side sliding contact portion 120a are urged in the axial direction. Therefore, it is not necessary to provide a compression coil spring that presses the power supply brush in the axial direction and a compression coil spring that presses the rectifying brush in the axial direction as in the prior art, so the number of compression coil springs 123 is reduced. As a result, the assembling property of the DC motor is improved and the productivity is improved.

  (8) The compression coil spring 123 is in a state where either one of the first power feeding unit 120b and the second power feeding unit 120f and the rectifying side sliding contact part 120a are connected to both ends and the conducting wire 120c is penetrated. It arrange | positions between either one of the 1st electric power feeding part 120b and the 2nd electric power feeding part 120f, and the rectification | straightening side sliding contact part 120a. Therefore, when the DC motor is assembled, the composite brush 120 and the compression coil spring 123 can be handled as one integrated part. Therefore, the DC motor can be assembled more easily.

Each embodiment of the present invention may be modified as follows.
In each of the above embodiments, the center lines L3, L5, L6, and L7 of the rectifying side sliding contact portions 50c, 81b, 82b, and 120a all coincide with the center line L2 of the magnet 44. However, the rectifying side sliding contact portions 50 c, 81 b, 82 b, 120 a may be arranged such that the center lines L 3, L 5, L 6, L 7 are shifted from the center line L 2 of the magnet 44.

  In the third embodiment, the compression coil spring 123 is arranged so that the conducting wire 120c penetrates the inside thereof. However, the compression coil spring 123 is arranged along the conducting wire 120c so that the first and second power feeding portions 120b and 120f are arranged. In addition, as long as both of the rectifying side sliding contact portions 120a can be urged in the axial direction, the conducting wire 120c does not have to penetrate therethrough.

  In the first and second embodiments, the slip rings 63 and 64 fixed to the slip ring holder 62 are urged in the axial direction toward the composite brushes 50, 81 and 82 by the compression coil spring 66. The composite brushes 50, 81, and 82 are relatively pressed against the slip rings 63 and 64, and the composite brushes 50, 81, and 82 are pressed against the commutator 31 (directly). However, the commutator 31 is urged in the axial direction toward the composite brushes 50, 81, 82 by the compression coil spring 66, thereby relatively (directly) pressing the composite brushes 50, 81, 82 against the commutator 31. At the same time, the composite brushes 50, 81, 82 may be pressed against the slip rings 63, 64. Even if it does in this way, there can exist an effect similar to the said 1st and 2nd embodiment.

  -In the said 2nd Embodiment, the composite brush 81,82 is provided 1 each corresponding to the anode side and the cathode side. However, the composite brush 81 may be divided into a plurality of pieces in the circumferential direction so as to have the first rectifying side sliding contact portion 81b, and the composite brush 82 may have the second rectifying side sliding contact portion 82b. It may be divided into a plurality of pieces in the circumferential direction. Even if it does in this way, there can exist an effect similar to above-mentioned (1) thru | or (4).

  In the first and second embodiments, the two slip rings 63 and 64 are pressed in the axial direction by one compression coil spring 66, but the compression coil springs that press the slip rings 63 and 64 are Each may be provided. Even if it does in this way, there can exist an effect similar to above-mentioned (1).

  In each of the above embodiments, the compression coil springs 66 and 123 are used as pressing means for pressing the composite brushes 50, 81, 82, and 120 directly or relatively in the axial direction against the slip rings 63 and 64 and the commutator 31. Although used, this pressing means is not limited to the compression coil springs 66 and 123. For example, the pressing means may be a spring other than a compression coil spring such as a leaf spring.

  In each of the above embodiments, the armature 21 and the commutator 31 are molded and integrated with the mold resin 34, but may not be integrated. In this case, the commutator 31 is provided separately from the armature 21 and is configured by partially burying the segment 32 and the connection line 33 in a holding portion made of an insulating resin material, for example, It is fixed to the armature 21 or the second case 12.

  In each of the above embodiments, the number of teeth 22 b of the armature core 22, the number of segments 32, the number of connection wires 33, the number of magnets 44 provided in the rotors 41, 71, 111, the composite brushes 50, 81, 82 , 120 may be appropriately changed.

The technical ideas that can be grasped from each of the above embodiments and each of the above modifications will be described below.
(A) The DC motor according to claim 5, wherein the compression coil spring is disposed so that the conductive wire penetrates in the axial direction. According to this configuration, the compression coil spring is disposed between the power supply brush and the rectifying brush in a state in which the conducting wire in which the power supply brush and the rectifying brush are connected to both ends is penetrated. Therefore, when the DC motor is assembled, the composite brush and the compression coil spring can be handled as one integrated part. Therefore, the DC motor can be assembled more easily.

  DESCRIPTION OF SYMBOLS 21 ... Armature, 23 ... Armature coil, 31 ... Commutator, 32 ... Segment, 33 ... Connection line, 41, 71, 111 ... Rotor, 42, 72 ... Rotating shaft, 43, 73, 112 ... Rotor core, 44 ... Magnets as field magnets, 46, 74, 113 ... Brush holders, 50, 51, 52, 81, 82, 120, 121, 122 ... Composite brushes, 50c, 120a ... Rectification side sliding contact portions as rectification brushes, 50d , 81a: first feeding side sliding contact portion as a feeding brush, 50e, 82a: second feeding side sliding contact portion as a feeding brush, 63, 64 ... slip ring, 66, 123 ... compression coil as pressing means Spring, 81b ... first rectifying side sliding contact portion as a rectifying brush, 82b ... second rectifying side sliding contact portion as a rectifying brush, 120b ... first feeding portion as a feeding brush, 120c ... Line, the second feeding portion as 120f ... power supply brush, L2 ... center line.

Claims (6)

An annular armature having a plurality of armature coils;
A rotor disposed inside the armature and having a rotating shaft, a rotor core fixed to the rotating shaft, and a field held by the rotor core;
A slip ring to which current is supplied;
A commutator having a plurality of segments that are juxtaposed in the circumferential direction and the armature coils are electrically connected to each other, and a connection line that electrically connects the segments at positions separated in the circumferential direction;
A plurality of power supply brushes slidably contacting the slip ring from an axial direction;
A plurality of rectifying brushes that are electrically connected to the power supply brush and slidably contact the commutator from an axial direction;
A DC motor that supplies current to the armature through the slip ring, the power supply brush, the rectifying brush, and the commutator,
The power supply brush and the rectifying brush are integrated with each other to form a composite brush,
A brush holder that is disposed inside the rotor core and holds the composite brush;
Pressing means for pressing the composite brush directly or relatively against the slip ring and the commutator;
A direct current motor comprising: The direct current motor according to claim 1,
A direct current motor characterized by pressing a plurality of the composite brushes directly or relative to the slip ring and the commutator with one pressing means. In the DC motor according to claim 1 or 2,
The slip ring is provided as a pair of an anode side slip ring and a cathode side slip ring,
There are only two composite brushes, and one of the composite brushes is directly or relatively pressed against the slip ring on the anode side and simultaneously contacts the plurality of segments located at circumferentially spaced positions, The other composite brush is directly or relatively pressed against the slip ring on the cathode side and simultaneously contacts a plurality of the segments at positions spaced apart in the circumferential direction. The motor according to any one of claims 1 to 3,
The commutator is disposed on one side in the axial direction of the rotor core, and the slip ring is disposed on the other side in the axial direction of the rotor core,
By urging one of the slip ring and the commutator in the axial direction with one pressing means, the plurality of composite brushes are urged toward the other of the slip ring and the commutator. A direct current motor. The direct current motor according to claim 1,
The commutator is disposed on one side in the axial direction of the rotor core, and the slip ring is disposed on the other side in the axial direction of the rotor core,
The composite brush is formed by connecting the power supply brush and the rectifying brush with a conductive wire,
The pressing means is a compression coil spring that is disposed along the conductor between the power supply brush and the rectifying brush in each composite brush and urges the power supply brush and the rectifying brush toward both sides in the axial direction. DC motor characterized by that. The DC motor according to any one of claims 1 to 5,
A plurality of the magnetic fields are arranged in the circumferential direction so that the N pole and the S pole are alternately arranged in the circumferential direction,
The composite brush has a rectifying side sliding contact portion that is in sliding contact with the commutator, and the rectifying side sliding contact portion is disposed on a center line of the field that extends in a radial direction through a central portion in a circumferential direction of the field. A direct current motor characterized by being arranged.

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