JP5292328B2 - Brush structure of outer armature motor - Google Patents

Description

  The present invention relates to a brush structure of an outer armature motor, and in particular, a slip ring fixed on the stator side and a brush that makes axial contact with a commutator are provided inside a rotor in which a permanent magnet is attached to an outer peripheral surface. The present invention relates to a brush structure of an outer armature motor.

  Conventionally, a motor including a rotor having a permanent magnet attached to an outer peripheral surface is known (see, for example, Patent Documents 1 and 2). In such a motor, a commutation brush is disposed inside the rotor, and the axial tip of the commutation brush is in contact with a commutator fixed on the stator side. The commutating brush is urged toward the commutator so that the contact with the commutator at the axial tip is maintained.

JP 2001-157314 A Special table 2007-507198 gazette

  By the way, in order to pass a current to the stator-side electric winding through the brush in the rotor, a stator-side slip ring connected to an external power source is connected to the brush along with a rectifying brush that contacts a commutator connected to the electric winding. It is necessary to integrally provide a power supply brush that contacts the surface. In this case, it is conceivable to provide a power supply brush at one axial end of the brush and a rectifying brush at the other axial end of the brush. In such a brush structure, either the slip ring on the stator side or the commutator can be displaced in the axial direction to bring the power supply brush into contact with the slip ring and the commutator brush into contact with the commutator. It is conceivable to provide an urging means for urging the slip ring or commutator with the brush toward the opposite side in the axial direction outside the slip ring or commutator after fixing the other. According to such a brush structure, since the force that compresses in the axial direction acts between the slip ring and the commutator by the urging means, both the contact of the power supply brush with the slip ring and the contact of the commutation brush with the commutator are performed. Can be secured.

  However, as described above, the biasing means is provided on the outside of the slip ring or the commutator in the axial direction, and the force is applied to the slip ring of the power supply brush and the commutator of the commutation brush by applying a force in one direction from the outside in the axial direction. In the brush structure that realizes pressurization, the pressurization path from the urging means to the commutator or slip ring via the brush becomes long and complicated. The reliability of contact with the commutator may be impaired.

  The present invention has been made in view of the above-described points. The pressure path from the biasing means to the slip ring via the power supply brush and the pressure path from the biasing means to the commutator via the rectifying brush are provided. It is an object of the present invention to provide a brush structure for an outer armature motor that can be shortened and simplified.

  The above-described object is to provide a rotor having a permanent magnet attached to the outer peripheral surface, a stator having an electric winding disposed on the outer peripheral side of the rotor so as to face the permanent magnet, and a non-rotatably fixed to the stator side. A slip ring that is electrically connected to an external power source, a commutator that is non-rotatably fixed to the stator side, and that is electrically connected to the electric winding, and a plurality of axial directions provided on the rotor. A brush structure of an outer armature motor, each of which is disposed inside a through-hole, wherein the brush is provided at one end in the axial direction and contacts the slip ring, and the other end in the axial direction A rectifying brush that is provided in contact with the commutator, and an urging means that is provided between the power supply brush and the rectifying brush and urges both the brushes outward in the axial direction. Energizing means is achieved by the brush structure of the outer armature motor constituted by the power supply member having conductivity.

  In the invention of this aspect, the urging means urges the power supply brush provided at one end in the axial direction and contacting the slip ring toward the slip ring, and the rectifying brush provided at the other end in the axial direction and contacting the commutator. Energize to the commutator side. In such a brush structure, the pressure path from the urging means to the slip ring via the power supply brush and the pressure path from the urging means to the commutator via the rectifying brush are both short and simplified.

  According to the present invention, it is possible to shorten and simplify both the pressure path from the biasing means to the slip ring via the power supply brush and the pressure path from the biasing means to the commutator via the rectifying brush.

It is a block diagram of the outer armature motor which is one Example of this invention. It is the figure at the time of seeing the inside of the outer side armature motor of a present Example from an axial direction.

  Hereinafter, specific embodiments of the present invention will be described with reference to the drawings.

  FIG. 1 shows a configuration diagram of an outer armature motor 10 according to an embodiment of the present invention. Moreover, FIG. 2 shows the figure at the time of seeing the inside of the outer side armature motor 10 of a present Example from an axial direction. An outer armature motor (hereinafter simply referred to as a motor) 10 according to the present embodiment is mounted on, for example, an electric steering device for a vehicle or a driving device for an electric vehicle, and its rotation shaft is coupled to a steering wheel, a tire wheel, or the like. It is a motor.

  The motor 10 includes a motor housing 12 that is fixed to the vehicle body side, a shaft 14 that transmits power, a cylindrical rotor 16 that is a rotatable rotor in which the shaft 14 is press-fitted and fixed at the center, and the motor housing 12. And a cylindrical stator 18 that is a non-rotatable stator that is attached to and fixed to the stator. The shaft 14 is rotatably supported by the motor housing 12 via bearings 20 and 22.

  The rotor 16 includes a permanent magnet 24, a laminated steel plate (rotor yoke) 26 that is laminated in the axial direction, a brush 28, and a brush holder 30. The permanent magnets 24 are arranged on the outer peripheral surface of the rotor 16 at regular intervals in the circumferential direction at predetermined angles (predetermined intervals; for example, 45 °), and a plurality (for example, eight as shown in FIG. 2) are provided. . The rotor 16 has a plurality of permanent magnets 24 in which N poles and S poles are alternately arranged in the circumferential direction.

  The laminated steel plate 26 has a cross-sectional shape formed in a polygon (for example, an octagon as shown in FIG. 2), and is formed into a multi-face structure so that the permanent magnets 24 are attached to the outer surface one by one. . The laminated steel plate 26 includes a shaft hole 26a through which the shaft 14 is inserted, an outer peripheral portion 26b on which one permanent magnet 24 is attached to each surface, and a radially extending outer peripheral portion 26b from the shaft hole 26a side. And a radiating portion 26c connected to the inner surface. The laminated steel plate 26 has hollow holes 26d penetrating in the axial direction by the number corresponding to the number of brass 28. Each hollow hole 26d has a cross-sectional shape surrounded by two radiating portions 26c and an outer peripheral portion 26b adjacent to each other in the circumferential direction, and is formed in a substantially fan shape.

  One brush 28 is disposed in each of the hollow holes 26d of the laminated steel plate 26. The brush 28 is held by a resin brush holder 30. Each brush 28 extends parallel to the shaft 14 and is erected in the radial direction from the axial center. Both ends of each brush 28 protrude outward in the axial direction from the axial end surface of the laminated steel plate 26. A power supply brush 28a is provided at one axial end of the brush 28 (left end portion in FIG. 1), and a rectifying brush 28b is provided at the other axial end of the brush 28 (right end portion in FIG. 1). .

  Between the power supply brush 28a of the brush 28 and the rectifying brush 28b, a biasing means 28c for generating a biasing force in the axial direction is provided. One urging means 28c is provided for each brush 28, and is integrated with the power supply brush 28a and the rectifying brush 28b. The urging means 28c is disposed in the hollow hole 26d of the laminated steel plate 26, and can be displaced in the axial direction within the hollow hole 26d. The biasing means 28c is a leaf spring having one axial end connected to the power supply brush 28a and the other axial end connected to the rectifying brush 28b. The biasing means 28c moves the power supply brush 28a outward in the axial direction (left side in FIG. 1). In addition to generating a biasing force, a force for biasing the rectifying brush 28b outward in the axial direction (right side in FIG. 1) is generated. The entire brush 28 including the power supply brush 28a, the rectifying brush 28b, and the urging means 28c is composed of a conductive member.

  Tubular slip rings 32 and 34 are attached and fixed to the motor housing 12. The slip rings 32, 34 are tubular members having different diameters, and the slip ring 32 is arranged on the inner diameter side of the slip ring 34 on the same axis. Hereinafter, the slip ring 32 is appropriately referred to as an inner diameter side slip ring 32, and the slip ring 34 is referred to as an outer diameter side slip ring 34, respectively.

  The slip rings 32 and 34 are electrically connected to an external DC power source. Each of the slip rings 32 and 34 has a sliding surface whose normal is directed in the axial direction, and is in contact with the power supply brush 28a of the brush 28 in the axial direction on the sliding surface. The power supply brush 28a is urged outward in the axial direction by the urging means 28c, so that the power supply brush 28a can move in the hollow hole 26d of the laminated steel plate 26, and the tip in the axial direction always contacts the slip rings 32 and 34. It is possible.

  Half of the total number of the brushes 28 (for example, four) of the power supply brushes 28a are in contact with the inner diameter side slip ring 32, and the other half of the power supply brushes 28a are in contact with the outer diameter side slip ring 34. Yes. The brush (+ potential brush) 28 in contact with the inner diameter side slip ring 32 and the brush (−potential brush) 28 in contact with the outer diameter side slip ring 34 are alternately arranged in the circumferential direction.

  A commutator 36 is also attached and fixed to the motor housing 12. The commutators 36 are arranged at regular intervals in the circumferential direction around the shaft 14 at predetermined angles (for example, 10 °), and a plurality (for example, 36) of commutators 36 are provided. Each commutator 36 has a sliding surface whose normal is directed in the axial direction, and is formed in a substantially fan shape. Each commutator 36 can be in axial contact with the straightening brush 28b of the brass 28 on the substantially fan-shaped sliding surface. The rectifying brush 28b is urged outward in the axial direction by the urging means 28c, so that the rectifying brush 28b can move in the hollow hole 26d of the laminated steel plate 26, and its axial tip can contact the commutator 36. It is. The commutator 36 has a function of rectifying the flowing current.

  The stator 18 is arranged on the outer peripheral side of the rotor 16 coaxially with the rotor 16 with a predetermined gap in the radial direction. The stator 18 has a plurality of cores 38 and a coil 40 wound around each core. The coils 40 are arranged at equal intervals in the circumferential direction around the shaft 14 at predetermined intervals (for example, 10 °), and a plurality (for example, 36) are provided. Each coil 40 is electrically connected to the corresponding commutator 36 one by one, and is supplied with power through the corresponding commutator 36.

  In the outer armature motor 10 described above, when a DC power supply is input from the outside to the slip rings 32 and 34, a current flows from the slip ring 32 to the brush 28 of the rotor 16 via the power supply brush 28a. The current flows to the commutator 36 on the stator 18 side via the urging means 28c and the rectifying brush 28b and is supplied to the coil 40, and the current flows from the coil 40 to the brush 28 via the commutator 36 and the rectifying brush 28b. Thereafter, the current flows to the slip ring 34 via the biasing means 28c and the power supply brush 28a. At this time, a magnetic circuit is formed between the stator 18 and the rotor 16 to generate a rotational magnetomotive force that rotates the rotor 16. For this reason, an attractive force or a repulsive force acts between the permanent magnet 24 on the rotor 16 side and the core 38 on the stator 18 side, and the rotor 16 and the shaft 14 rotate.

  In the present embodiment, the brush 28 of the motor 10 includes a power supply brush 28a and a rectifying brush 28b provided at both ends in the axial direction, and a biasing means 28c for connecting the brushes 28a and 28b. The urging means 28c urges the power supply brush 28a toward the slip rings 32 and 34 in the axial direction, and urges the rectifying brush 28b toward the commutator 36 in the axial direction.

  That is, in the motor 10 of this embodiment, the brush 28 is divided into two parts, the power supply brush 28a side and the rectifying brush 28b side, and the brush 28 urges both the power supply brush 28a and the rectifying brush 28b outward in the axial direction. The urging means 28c is provided, and the urging force of the urging means 28c ensures contact between the power supply brush 28a and the slip rings 32 and 34, and also ensures contact between the rectifying brush 28b and the commutator 36. Is done.

  In such a brush structure, in order to ensure each of these contacts, a pressure path from the biasing means 28c to the slip rings 32 and 34 via the power supply brush 28a and a commutator from the biasing means 28c via the rectifying brush 28b. The pressurization path to 36 is both short and simplified. For this reason, according to the brush structure of the present embodiment, the sliding failure between the power supply brush 28a and the slip rings 32 and 34 and the rectifying brush 28b and the commutator are compared with those having a long pressure path and a complicated brush structure. It is possible to reduce the sliding failure with the power supply 36, improve the reliability of the contact of the power supply brush 28a with the slip rings 32, 34 and the contact of the commutation brush 28b with the commutator 36, and motor efficiency. It is possible to improve.

  Further, since the pressing from the urging means 28c to the power supply brush 28a and the pressing from the urging means 28c to the rectifying brush 28b are performed for each brush 28 at the radial center of the brush 28, the offset from the radial center. Unlike the structure performed in this respect, it is possible to suppress the occurrence of a moment accompanying the pressurization in the axial direction on the brush 28 itself. For this reason, according to the brush structure of the present embodiment, it is possible to suppress the sliding failure of the brush 28 and reduce the electric resistance value, and to improve the motor efficiency.

  Further, since the rotor 16 is a cylindrical member extending in the axial direction, the brush 28 in the hollow hole 26d of the laminated steel plate 26 has a long shape in the axial direction. Biasing means 28c made of a leaf spring is provided between 28a and the rectifying brush 28b. For this reason, according to the brush structure of the present embodiment, compared with the brush structure in which the urging means 28c is not provided between the power supply brush 28a and the rectifying brush 28b, the electric power of the brush 28 having a long shape in the axial direction. The resistance value can be prevented from becoming excessive, and the motor efficiency can be improved.

  Further, since each of the brushes 28 is provided with a biasing means 28c for biasing both the brushes 28a and 28b outward in the axial direction between the power supply brush 28a and the rectifying brush 28b, the axially outer side of the rotor 16 (for example, slip ring) 32, 34 axially outside of the commutator 36 and axially outside of the commutator 36), the contact between the power supply brush 28 a and the slip rings 32, 34 is secured to all the brushes 28, and the commutator brush 28 b and the commutator 36 are in contact with each other. It is not necessary to provide a large biasing means for ensuring contact. Therefore, according to the brush structure of the present embodiment, it is possible to reduce the space outside the rotor 16 in the axial direction and reduce the size of the entire motor 10.

  In the present embodiment, the biasing means 28c between the power supply brush 28a and the rectifying brush 28b is a leaf spring, so that the contact with the power supply brush 28a and the rectifying brush 28b is less than that in the structure of a coil spring. The area can be increased, and the biasing means 28c of the brush 28 can be used as a power supply member.

  In the above-described embodiment, the leaf spring is used as the biasing means 28c between the power supply brush 28a and the rectifying brush 28b. However, the present invention is not limited to this and is used as a power supply member. If possible, a compression spring may be used.

DESCRIPTION OF SYMBOLS 10 Outer armature motor 16 Rotor 18 Stator 24 Permanent magnet 26 Laminated steel plate 26b Outer peripheral part 26d Hollow hole 28 Brush 28a Power supply brush 28b Commutation brush 28c Energizing means 36 Commutator 40 Coil

Claims (1)

A rotor to which a permanent magnet is attached on the outer peripheral surface, a stator having an electric winding disposed on the outer peripheral side of the rotor so as to face the permanent magnet, and an external power source fixed to the stator side so as not to rotate A slip ring that is electrically connected to the stator, a commutator that is non-rotatably fixed to the stator side, and that is electrically connected to the electric winding, and a plurality of axially penetrating holes provided in the rotor A brush structure of an outer armature motor comprising:
The brush is provided between the power supply brush and the rectifying brush provided at one end in the axial direction and in contact with the slip ring, a rectifying brush provided at the other end in the axial direction and in contact with the commutator. Urging means for urging both brushes outward in the axial direction,
The outer armature motor brush structure, wherein the urging means is constituted by a power supply member having conductivity.

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