WO2024084844A1 - Electric motor - Google Patents

Electric motor Download PDF

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Publication number
WO2024084844A1
WO2024084844A1 PCT/JP2023/032158 JP2023032158W WO2024084844A1 WO 2024084844 A1 WO2024084844 A1 WO 2024084844A1 JP 2023032158 W JP2023032158 W JP 2023032158W WO 2024084844 A1 WO2024084844 A1 WO 2024084844A1
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WO
WIPO (PCT)
Prior art keywords
brush
electric motor
commutator
spring
arc
Prior art date
Application number
PCT/JP2023/032158
Other languages
French (fr)
Japanese (ja)
Inventor
圭策 中野
和雄 遠矢
Original Assignee
パナソニックＩｐマネジメント株式会社
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by パナソニックＩｐマネジメント株式会社 filed Critical パナソニックＩｐマネジメント株式会社
Publication of WO2024084844A1 publication Critical patent/WO2024084844A1/en

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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01R—ELECTRICALLY-CONDUCTIVE CONNECTIONS; STRUCTURAL ASSOCIATIONS OF A PLURALITY OF MUTUALLY-INSULATED ELECTRICAL CONNECTING ELEMENTS; COUPLING DEVICES; CURRENT COLLECTORS
    • H01R39/00—Rotary current collectors, distributors or interrupters
    • H01R39/02—Details for dynamo electric machines
    • H01R39/18—Contacts for co-operation with commutator or slip-ring, e.g. contact brush
    • H01R39/26—Solid sliding contacts, e.g. carbon brush
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02K—DYNAMO-ELECTRIC MACHINES
    • H02K13/00—Structural associations of current collectors with motors or generators, e.g. brush mounting plates or connections to windings; Disposition of current collectors in motors or generators; Arrangements for improving commutation

Definitions

  • This disclosure relates to electric motors.
  • Electric motors are widely used in household electrical appliances such as vacuum cleaners, as well as in the electrical equipment field of automobiles.
  • electric motors are used in two-wheeled and four-wheeled vehicles to drive cooling fans such as radiators.
  • brushed motors include a stator, rotor, commutator, brushes, a brush holder, and a brush spring.
  • the rotor rotates due to the magnetic force of the stator.
  • the commutator is attached to the rotating shaft of the rotor.
  • the brushes are in sliding contact with the commutator.
  • the brush holder holds the brushes.
  • the brush spring presses the brushes against the commutator.
  • a brushed electric motor has a power supply terminal that receives power from an external power source to be supplied to the brushes, and a conductive wire that electrically connects the brushes and the power supply terminal.
  • One end of the conductive wire is fixed to the brush, and the other end is electrically connected to the power supply terminal.
  • a pigtail wire is used as the conductive wire.
  • the conductive wire connecting the brush and the power terminal moves with the end connected to the power terminal as the brush wears and becomes shorter. As the conductive wire moves, it sags, changing shape, etc.
  • the arc-shaped brushes are long, so the length of the conductive wires connecting the brushes to the power terminals is also long. For this reason, the conductive wires connected to the arc-shaped brushes are prone to sagging when the brushes wear and become shorter. In other words, the conductive wires connected to the arc-shaped brushes move more.
  • the conductive wires connecting the brushes and the power terminals are placed in the brush holder together with the brushes.
  • the brush holder has uneven structures of various sizes, such as brush storage areas. Therefore, when the conductive wires placed in the brush holder move as the brushes wear, they can interfere with the uneven structure of the brush holder. This can result in problems such as a reduction in the pressure load when the brush presses against the commutator due to the brush spring. In other words, the load stability of the brush is reduced.
  • the present disclosure has been made to solve such problems.
  • the purpose of the present disclosure is to provide an electric motor that can prevent the load stability of the brush from being reduced due to the conductive wire connected to the brush, even in a motor that uses an arc-shaped brush.
  • one embodiment of the electric motor according to the present disclosure comprises a rotating shaft whose axial direction is the direction in which the shaft extends, a commutator attached to the rotating shaft, a brush in contact with the commutator, a brush holder that holds the brush, a terminal attached to the brush holder, and a conductive wire having one end connected to the brush and the other end electrically connected to the terminal, the brush being arc-shaped, and the terminal being located inside the brush.
  • FIG. 1 is an external perspective view of an electric motor according to a first embodiment of the present invention, as viewed obliquely from above.
  • FIG. 2 is an external perspective view of the electric motor according to the first embodiment as viewed obliquely from below.
  • FIG. 3 is a cross-sectional perspective view of the electric motor according to the first embodiment.
  • FIG. 4 is an exploded perspective view of the electric motor according to the first embodiment.
  • FIG. 5A is a top view showing a brush holder in which various components are arranged and a commutator in the electric motor according to the first embodiment.
  • FIG. 5B is a diagram showing the relationship between the commutator, the brushes, and the brush springs in the electric motor according to embodiment 1.
  • FIG. 5A is a top view showing a brush holder in which various components are arranged and a commutator in the electric motor according to the first embodiment.
  • FIG. 5B is a diagram showing the relationship between the commutator, the brushes, and the brush spring
  • FIG. 6 is a perspective view showing a brush holder in which various components are arranged and a commutator in the electric motor according to the first embodiment.
  • FIG. 7 is a perspective view showing the positional relationship between the pair of brushes, the pair of brush springs, and the commutator in FIG.
  • FIG. 8 is a top view showing the positional relationship between one brush, one brush spring, and a commutator in FIG.
  • FIG. 9 is a perspective view of a brush holder in the electric motor according to the first embodiment.
  • FIG. 10 is a perspective view of the brush spring in a state where the strip-shaped wire is housed in the spiral portion.
  • FIG. 11 is a diagram showing a state in which the brush spring and the brush in the state shown in FIG. 10 are set in the brush holder.
  • FIG. 12 is a diagram for explaining a state in which the brush and the brush spring are fixed to the brush holder.
  • FIG. 13 is a diagram showing how the brush slides due to wear.
  • FIG. 14 is a top view of a brush holder in which brushes and brush springs are arranged in the electric motor according to the second embodiment.
  • FIG. 15 is an enlarged view of the contact point between the front end face of the brush and the commutator and the surrounding area in FIG.
  • FIG. 16 is a perspective view of a brush holder in which brushes and brush springs are arranged in the electric motor according to the third embodiment.
  • FIG. 17 is an enlarged view of the rear end portion of the brush and its surrounding area in FIG.
  • FIG. 18 is a perspective view of a brush and conductive wires included in the electric motor according to the third embodiment.
  • FIG. 19 is a diagram for explaining the arrangement of brushes in an electric motor according to a modified example.
  • FIG. 1 Each figure is a schematic diagram and is not necessarily a precise illustration.
  • the same reference numerals are used for configurations that are substantially the same as in other figures, and duplicate explanations are omitted or simplified.
  • the terms “upper” and “lower” do not necessarily refer to the upper direction (vertically upward) and the lower direction (vertically downward) in an absolute spatial sense.
  • Fig. 1 is an external perspective view of the electric motor 1 according to the first embodiment when viewed obliquely from above.
  • Fig. 2 is an external perspective view of the electric motor 1 according to the first embodiment when viewed obliquely from below.
  • Fig. 3 is a cross-sectional perspective view of the electric motor 1 according to the first embodiment.
  • Fig. 4 is an exploded perspective view of the electric motor 1 according to the first embodiment.
  • Fig. 5A is a top view showing the brush holder 60 and the commutator 30 on which various components are arranged in the electric motor 1 according to the first embodiment.
  • FIG. 5B is a diagram showing the relationship between the commutator 30, the brushes 40, and the brush springs 50 in the electric motor 1 according to the first embodiment.
  • Fig. 6 is a perspective view showing the brush holder 60 and the commutator 30 on which various components are arranged in the electric motor 1 according to the first embodiment.
  • the electric motor 1 includes a stator 10 and a rotor 20 that rotates due to the magnetic force of the stator 10.
  • the electric motor 1 is a brushed electric motor.
  • the electric motor 1 includes a commutator 30, at least one brush 40, a brush spring 50, and a brush holder 60.
  • the commutator 30 is attached to a rotating shaft 21 of the rotor 20. At least one brush 40 contacts the commutator 30.
  • the brush spring 50 presses the brush 40 against the commutator 30.
  • the brush holder 60 holds the brush 40.
  • the electric motor 1 includes a terminal 70 that receives power from an external power source, and a conductive wire 80 that is electrically connected to the terminal 70 and the brush 40.
  • the electric motor 1 further includes a first bearing 91, a second bearing 92, a first bracket 101, and a second bracket 102.
  • the electric motor 1 is a type of direct current motor (DC motor) that is driven by direct current.
  • a magnet is used as the stator 10.
  • an armature having a coil 22 is used as the rotor 20.
  • the electric motor 1 is a flat type (flat type) brushed coreless motor (flat motor) that is mounted on a vehicle such as a two-wheeled or four-wheeled vehicle. Therefore, the stator 10 and the rotor 20 do not have a core (iron core).
  • the electric motor 1 is configured to be thin and lightweight overall. Specifically, the electric motor 1 is a small motor used in a cooling fan for a radiator in a vehicle.
  • the electric motor 1 is driven by an input voltage of, for example, DC 12V.
  • the stator 10 is disposed with a small air gap between it and the rotor 20.
  • the stator 10 generates a magnetic force acting on the rotor 20.
  • the stator 10 is configured to generate magnetic flux on the air gap surface with the rotor 20.
  • the stator 10 forms a magnetic circuit together with the rotor 20, which is an armature.
  • the stator 10 is generally annular.
  • the stator 10 is magnetized so that N poles and S poles are alternately and evenly present on the air gap surface with the rotor 20 along the circumferential direction of the rotating shaft 21.
  • the stator 10 is a field magnet that creates magnetic flux to generate torque.
  • the stator 10 is composed of, for example, a permanent magnet.
  • the direction of the main magnetic flux generated by the stator 10 (magnet) is the direction in which the rotating shaft 21 extends.
  • the stator 10 is fixed to a first bracket 101.
  • the rotor 20 has a rotating shaft 21 and a coil 22.
  • the rotor 20 is a coreless rotor that does not have a core.
  • the rotor 20 rotates around the axis C of the rotating shaft 21.
  • the rotor 20 generates a magnetic force that acts on the stator 10.
  • the direction of the main magnetic flux generated by the rotor 20 is the direction in which the rotating shaft 21 extends.
  • the rotor 20 is disposed opposite the stator 10.
  • the rotor 20 faces the stator 10 in the direction in which the rotating shaft 21 extends.
  • the coils 22 contained in the rotor 20 and the stator 10 face each other in the direction in which the rotating shaft 21 extends.
  • the rotating shaft 21 is a shaft having an axis C.
  • the rotating shaft 21 is a long rod-shaped member.
  • the rotating shaft 21 is a metal rod made of a metal material such as SUS (Steel special use stainless steel).
  • the axis C of the rotating shaft 21 is the center when the rotor 20 rotates.
  • the longitudinal direction of the rotating shaft 21, i.e., the direction in which the rotating shaft 21 extends, is the direction of the axis C (axial direction).
  • the first end 21a which is one end of the rotating shaft 21, is supported by a first bearing 91.
  • the second end 21b which is the other end of the rotating shaft 21, is supported by a second bearing 92.
  • the first bearing 91 and the second bearing 92 are bearings such as ball bearings.
  • the first end 21a of the rotating shaft 21 is the output side end (output shaft).
  • the first end 21a of the rotating shaft 21 protrudes from the first bracket 101 and the first bearing 91.
  • a load such as a rotating fan is attached to the first end 21a.
  • the second end 21b of the rotating shaft 21 is the anti-output side end (anti-output shaft).
  • the second end 21b of the rotating shaft 21 does not protrude from the second bracket 102 and the second bearing 92.
  • the first bearing 91 is held by the first bracket 101. Specifically, the first bearing 91 is fixed to a recess provided in the center of the first bracket 101.
  • the second bearing 92 is held by the brush holder 60. Specifically, the second bearing 92 is fixed to a recess provided in the center of the brush holder 60.
  • the first bracket 101 and the second bracket 102 are made of, for example, a metal material.
  • the first bracket 101 and the second bracket 102 are made of an iron-based material such as cold-rolled steel plate (SPC (Steel Plate Cold) material) or a metal such as aluminum.
  • the material of the first bracket 101 and the second bracket 102 is not limited to a metal material and may be a resin material. However, from the viewpoint of suppressing noise generated from the electric motor 1, it is preferable that the first bracket 101 and the second bracket 102 are made of a metal material.
  • the first bracket 101 is an outer shell member of the electric motor 1.
  • the first bracket 101 is a thin, flat cylinder having a bottom and a cylindrical side wall.
  • the second bracket 102 is a flat plate with a through hole.
  • the first bracket 101 and the brush holder 60 form an outer shell housing.
  • the stator 10 and rotor 20 are arranged inside this outer shell housing.
  • the rotor 20 has a rotating shaft 21, multiple coils 22, and molded resin 23.
  • the multiple coils 22 are wound coils. Specifically, the multiple coils 22 are armature windings made of electric wire. The multiple coils 22 are wound so that a magnetic force acting on the stator 10 is generated when a current flows through them. The direction of the main magnetic flux generated by the coils 22 is along the axis C to which the rotating shaft 21 extends. Specifically, the multiple coils 22 are wound in a flat shape. The coil surfaces of the multiple coils are arranged in a position facing in a direction along the axis C to which the rotating shaft 21 extends.
  • the coils 22 are composed of an insulated wire having a core wire made of a metal such as copper or aluminum and an insulating film coating the core wire.
  • the multiple coils 22 are thin wound coils having a coil layer in which the insulated wire is wound in a planar shape.
  • the multiple coils 22 are composed of, for example, one layer or multiple coil layers in which the insulated wire is wound in a substantially fan-like shape in a planar view.
  • the multiple coils 22 thus configured are arranged in a ring shape surrounding the rotating shaft 21 when viewed from the direction of the axis C along which the rotating shaft 21 extends.
  • the multiple coils 22 are electrically connected to the commutator 30. Specifically, the multiple coils 22 are electrically connected to one of the multiple commutator segments 31 that the commutator 30 has. Therefore, current flows through the multiple coils 22 via the commutator segment 31 that the brush 40 contacts.
  • the multiple coils 22 are molded integrally with the molded resin 23 by being covered with the molded resin 23.
  • the multiple coils 22 are resin molded. Therefore, as shown in FIG. 4, the external shape of the molded resin 23 after the multiple coils 22 are molded is circular in a plan view.
  • an insulating resin material such as phenolic resin or unsaturated polyester (BMC (Bulk Molding Compound)
  • BMC Bulk Molding Compound
  • the molded resin 23 may be either a thermosetting resin or a thermoplastic resin. As shown in FIG. 3, the molded resin 23 is fixed to the rotating shaft 21 via a cylindrical member 24.
  • the electric motor 1 is a coreless motor in which the rotor 20 does not have a core.
  • the multiple coils 22 of the rotor 20 of the electric motor 1 are thin and molded from resin. This makes it possible to realize a thin electric motor 1 with low inductance.
  • the commutator 30 is attached to the rotating shaft 21. Therefore, the commutator 30 rotates together with the rotating shaft 21 as the rotor 20 rotates.
  • the commutator 30 attached to the rotating shaft 21 may be a part of the rotor 20.
  • the commutator 30 has a plurality of commutator pieces 31 (commutator segments) arranged along the rotational direction of the rotating shaft 21.
  • the plurality of commutator pieces 31 are arranged in an annular shape along the rotational direction of the rotating shaft 21 so as to surround the rotating shaft 21.
  • Each commutator piece 31 is shaped as an elongated member extending in the longitudinal direction of the rotating shaft 21.
  • Each commutator piece 31 is formed so as to have a step on its surface.
  • the multiple commutator segments 31 are conductive terminals made of a metal material such as copper.
  • the multiple commutator segments 31 are electrically connected to the coils 22 of the rotor 20.
  • the multiple commutator segments 31 are arranged insulated and separated from each other.
  • the multiple commutator segments 31 are each electrically connected by the coils 22 of the rotor 20.
  • the commutator 30 is a molded commutator.
  • the commutator 30 is configured with multiple commutator segments 31 molded with resin. In this case, the multiple commutator segments 31 are embedded in the resin so that their surfaces are exposed.
  • the multiple commutator segments 31 are fixed to the rotating shaft 21 by fixing the resin that molds the multiple commutator segments 31 to the rotating shaft 21.
  • the molded resin that covers the multiple commutator segments 31 and the molded resin 23 that covers the coil 22 are integrated.
  • the molded resin that covers the multiple commutator segments 31 and the molded resin 23 that covers the coil 22 may be made of the same resin material, or may be separate bodies made of different resin materials or the same resin material.
  • At least one brush 40 is in contact with the commutator 30. Specifically, the tip of the brush 40 is in contact with the commutator segments 31 of the commutator 30. The brush 40 is in contact with the commutator segments 31 in a direction (radial direction) perpendicular to the direction of the axis C of the rotating shaft 21. Since the commutator 30 rotates due to the rotation of the rotating shaft 21, the brush 40 continues to come into contact with all the commutator segments 31 in sequence.
  • Brush 40 is a power supply brush for supplying power to coil 22.
  • Brush 40 is connected to conductive wire 80, which is electrically connected to terminal 70.
  • the current (armature current) supplied to brush 40 via conductive wire 80 flows through commutator segments 31 to coil 22 of rotor 20.
  • Brush 40 is a conductive carbon brush whose main component is carbon.
  • brush 40 is preferably a carbon brush containing a metal such as copper. This can reduce the contact resistance between brush 40 and commutator segments 31.
  • brush 40 is a sintered brush made of a sintered body.
  • brush 40 which is a sintered body, can be produced, for example, by putting a mixture of graphite powder, copper powder, binder resin, and hardener into a mold, compression molding, and sintering.
  • brush 40 is produced without cutting.
  • brush 40 is produced after graphite powder and copper powder are put into a mold, compression molding, and sintering, and then no cutting is performed.
  • the brush 40 is arc-shaped. Specifically, the cross-sectional shape of the brush 40 is substantially rectangular.
  • the brush 40 has a shape that forms an arc when viewed from above. When viewed from above, the width of the brush 40 is constant.
  • the top view shape of the arc-shaped brush 40 does not have to be strictly an arc, but may be approximately an arc.
  • the brush 40 has a pair of opposite side surfaces, a first side surface 41 and a second side surface 42.
  • the first side surface 41 is the side surface on the outer periphery of the arc that constitutes the brush 40.
  • the second side surface 42 is the side surface on the inner periphery of the arc that constitutes the brush 40.
  • the curvature of the arc of the first side surface 41 on the outer periphery is smaller than the curvature of the arc of the second side surface 42 on the inner periphery.
  • the first side surface 41 and the second side surface 42 are cylindrical surfaces. Therefore, the circle that forms the arc of the first side surface 41 has one center point. Similarly, the circle that forms the arc of the second side surface 42 also has one center point. The center point of the circle that forms the arc of the first side surface 41 and the center point of the circle that forms the arc of the second side surface 42 are the same. In other words, the circle that forms the arc of the first side surface 41 and the circle that forms the arc of the second side surface 42 are concentric circles. Note that the center point of the circle that forms the arc of the first side surface 41 and the center point of the circle that forms the arc of the second side surface 42 do not have to be the same.
  • the brush 40 has a front end face 43 which is a surface that contacts the commutator 30, and a rear end face 44 which is a surface opposite to the front end face 43.
  • the front end face 43 is an end face at the front end, which is one end in the longitudinal direction of the brush 40.
  • the front end face 43 is a sliding surface that comes into sliding contact with the commutator pieces 31 of the commutator 30.
  • the rear end face 44 is an end face at the rear end, which is the other end in the longitudinal direction of the brush 40.
  • the rear end face 44 is a surface that comes into contact with the spiral portion 51 of the brush spring 50.
  • the front end surface 43 and the rear end surface 44 are substantially rectangular flat surfaces. However, this is not limited thereto.
  • the front end surface 43 may be a concave curved surface that curves along the surface shape of the commutator piece 31.
  • the rear end surface 44 may be a concave curved surface that curves along the surface shape of the spiral portion 51 so that a part of the spiral portion 51 of the brush spring 50 is accommodated therein.
  • the front end surface 43 of the brush 40 contacts the commutator 30 so that the center line of the front end surface 43 is perpendicular to the surface of the commutator 30.
  • the angle between the tangent line of the brush 40 and the direction of rotation of the motor 1 is 90° (see the enlarged portion of Figure 5B).
  • Multiple brushes 40 are arranged.
  • the multiple brushes 40 are arranged at equal intervals along the rotation direction of the rotor 20.
  • two brushes 40 are arranged.
  • the two brushes 40 are arranged opposite each other with the commutator 30 in between.
  • the two brushes 40 are arranged at 180° intervals along the rotation direction of the rotor 20.
  • the front end face 43 of one brush 40 and the front end face 43 of the other brush 40 face each other with the rotation shaft 21 in between.
  • Each of the two brushes 40 is elongated. As shown in FIG. 5B , if the center of the circle forming the arc of the brush 40 is taken as the center point, the angle ⁇ between the line connecting this center point to the front end surface 43 of the brush 40 and the line connecting the center point to the rear end surface 44 of the brush 40 is 90° or more ( ⁇ 90°). In other words, the central angle of the arc of the brush 40 of both brushes 40 is 90° or more. Specifically, in both brushes 40, the first side surface 41 and the second side surface 42 both have central angles of the arc of 90° or more.
  • the two brushes 40 have the same shape. However, this is not limited to this.
  • the brush 40 is constantly in contact with the commutator segments 31 of the commutator 30 due to the pressing force of the brush spring 50. Specifically, as shown in FIG. 5B, the brush 40 is pressed against the commutator 30 by the brush spring 50, so that the front end surface 43 of the brush 40 is in contact with the commutator segments 31. The brush 40 wears out due to its continuous contact with the rotating commutator segments 31. In this way, the brush 40 is in sliding contact with the commutator 30 due to the pressing force of the brush spring 50. At the same time, the brush 40 becomes shorter due to wear caused by the commutator 30.
  • the brush springs 50 are provided according to the number of brushes 40. Since the electric motor 1 is provided with two brushes 40, two brush springs 50 are also provided. The brushes 40 and brush springs 50 are held in the brush holder 60.
  • the brush spring 50 applies a pressure (spring pressure) to the brush 40 by the spring elastic force.
  • the brush spring 50 biases the brush 40 toward the commutator 30.
  • the brush spring 50 is a constant load spring. Therefore, the brush spring 50 applies a uniform load to the brush 40. In other words, the brush spring 50 applies a uniform pressure to the brush 40 from the initial stage before the brush 40 wears out to the final stage when the brush 40 wears out and the motor 1 reaches the end of its life.
  • the brush spring 50 which is a constant-load spring, is made of a strip-shaped wire material. As shown in Figures 4 to 6, the brush spring 50 is a spiral spring. The brush spring 50 has a spiral portion 51 (coil portion) in which a strip-shaped wire material is wound in a spiral shape. The brush spring 50 is made of a single strip-shaped wire material made of a metal material such as a steel plate.
  • the wire that constitutes brush spring 50 is a long, band-shaped metal plate.
  • spiral portion 51 is the portion of the constant-load spring in which the long, band-shaped metal plate is wound in a spiral shape multiple times in only one direction.
  • Brush spring 50 generates a force (spring restoring force) that returns the wire to its original spiral state by stretching one end of the wire from spiral portion 51.
  • brush spring 50 is made of a stainless steel metal plate.
  • the brush spring 50 has an outer end 50a which is one end of a strip of metal plate, and an inner end 50b which is the other end of the strip of metal plate.
  • the outer end 50a is one end of the strip of metal plate that is pulled outward from the outermost periphery of the spiral portion 51.
  • the inner end 50b is the other end of the strip of metal plate that is located at the innermost periphery of the spiral portion 51.
  • the brush spring 50 presses the brush 40 against the commutator 30 with the spiral portion 51. Specifically, the spiral portion 51 of the brush spring 50 contacts the rear end surface 44 of the brush 40.
  • the brush spring 50 applies a pressing load to the brush 40 with the spring restoring force of the spiral portion 51.
  • the brush spring 50 applies a pressing force (spring pressure) to the brush 40 with the spiral portion 51. This biases the brush 40 towards the commutator 30.
  • FIG. 7 is a perspective view showing the positional relationship between a pair of brushes 40, a pair of brush springs 50, and the commutator 30 in FIG. 6.
  • FIG. 8 is a top view showing the positional relationship between one brush 40, one brush spring 50, and the commutator 30 in FIG. 7. As shown in FIGS. 7 and 8, the brush spring 50 is positioned so as to contact the first side surface 41, which is the side surface on the outer periphery of the brush 40.
  • a strip of wire (metal plate) pulled out from the spiral portion 51 of the brush spring 50 extends along the first side surface 41 of the brush 40. Therefore, the strip of wire pulled out from the spiral portion 51 of the brush spring 50 is curved in an arc, just like the brush 40.
  • the width of the wire constituting the brush spring 50 should be between 1/3 and 2/3 of the width of the first side surface 41 of the brush 40. This improves the sliding properties between the brush spring 50 and the brush 40, while allowing the brush spring 50 to apply a stable pressure load to the brush 40.
  • the brush 40 is held by the brush holder 60.
  • the brush holder 60 is also an outer shell member that constitutes the outer shell of the electric motor 1.
  • the brush holder 60 covers the second bracket 102 from the outside.
  • the brush holder 60 is made of, for example, an insulating resin material.
  • the brush holder 60 is a resin molded product formed by integral molding using a resin material.
  • the resin material that makes up the brush holder 60 is phenolic resin. However, this is not limited to this.
  • the brush holder 60 has a brush storage section 60a, which is a spatial area in which the brush 40 is stored.
  • the brush storage section 60a is a recessed portion formed in a concave shape.
  • the brush storage section 60a is formed in an elongated shape that conforms to the shape of the brush 40. In other words, the brush storage section 60a is curved in an arc shape.
  • Figure 9 is a perspective view of the brush holder 60 in the electric motor 1 according to the first embodiment. As shown in Figure 9, both ends of the brush storage section 60a in the longitudinal direction are both open. In other words, the brush storage section 60a is not only open at the front end on the front end surface 43 side of the brush 40, but also at the rear end on the rear end surface 44 side of the brush 40.
  • the brush storage section 60a stores the brush spring 50 together with the brush 40. Therefore, the longitudinal length of the brush storage section 60a is longer than the length of the brush 40.
  • the brush spring 50 is arranged in the brush storage section 60a so that the spiral portion 51 is located rearward of the rear end of the brush 40.
  • the strip-shaped wire material (metal plate) constituting the brush spring 50 is pulled out from the spiral portion 51 toward the commutator 30 along the arc shape of the brush storage section 60a.
  • the strip-shaped wire material constituting the brush spring 50 is pulled out from the spiral portion 51 along the first side surface 41 of the brush 40.
  • the outer end 50a of the strip-shaped wire pulled out from the spiral portion 51 of the brush spring 50 is fixed to a fixing portion 60b formed near the opening at the front end of the brush storage portion 60a in the brush holder 60.
  • the fixing portion 60b to which the outer end 50a of the brush spring 50 is fixed is a notched groove.
  • the outer end 50a of the brush spring 50 is fixed to the fixing portion 60b by engaging the V-shaped bent portion formed at the outer end 50a of the brush spring 50 with the fixing portion 60b.
  • the brush 40 stored in the brush storage section 60a is covered by a cover plate 110.
  • the brush spring 50 is also stored in the brush storage section 60a. Therefore, the cover plate 110 not only covers the brush 40, but also the brush spring 50.
  • the cover plate 110 is, for example, a metal cover made of a metal plate.
  • the cover plate 110 is arranged so as to cover the brush storage section 60a.
  • the cover plate 110 is provided with a locking claw. By inserting this locking claw into a locking hole formed in the brush holder 60, the cover plate 110 can be fixed to the brush holder 60.
  • the brush storage sections 60a are formed according to the number of brushes 40. Since there are two brushes 40, two brush storage sections 60a are formed in the brush holder 60. The two brush storage sections 60a are long in the direction in which the brushes 40 extend. Furthermore, the two brush storage sections 60a are formed with a rectangular concave cross-sectional shape.
  • the brush storage section 60a has a first side wall 61, a second side wall 62, and a bottom wall 63.
  • the first side wall 61 faces the first side surface 41 of the brush 40.
  • the second side wall 62 faces the second side surface 42 of the brush 40.
  • the bottom wall 63 supports the bottom surface of the brush 40.
  • the first side wall 61 and the second side wall 62 are a pair of side walls that sandwich the brush 40.
  • the first side wall 61 and the second side wall 62 are formed in an arc shape, similar to the arc shape of the brush 40.
  • a fixing portion 60b (locking hole) to which the outer end portion 50a of the brush spring 50 is fixed is formed at the end portion of the first side wall 61 on the commutator 30 side.
  • the first side wall 61 has an arc-shaped side wall surface that faces the first side surface 41, which is the side surface on the outer periphery of the brush 40.
  • the second side wall 62 has an arc-shaped side wall surface that faces the second side surface 42, which is the side surface on the inner periphery of the brush 40.
  • the brush storage section 60a has a shape that allows the brush 40 to rotate once along the brush storage section 60a. In other words, even if the arc-shaped brush 40 is rotated once along the brush storage section 60a, there is no obstacle in the brush holder 60 that the brush 40 comes into contact with. Since the brush 40 is arc-shaped, the brush storage section 60a is formed to form at least a part of the circle that constitutes the arc of the brush 40. Specifically, the shape of the first side wall 61 and the second side wall 62 when viewed from above is an arc of the circle that constitutes the arc of the brush 40.
  • the distance between the first side wall 61 and the second side wall 62 is constant. Therefore, the curvature of the arc of the first side wall 61 on the outer periphery side is smaller than the curvature of the arc of the second side wall 62 on the inner periphery side.
  • the side wall surfaces of the first side wall 61 and the second side wall 62 are cylindrical surfaces. Therefore, the circle forming the arc of the first side wall 61 has one center point. Similarly, the circle forming the arc of the second side wall 62 also has one center point. The center point of the circle forming the arc of the side wall surface of the first side wall 61 and the center point of the circle forming the arc of the side wall surface of the second side wall 62 are concentric.
  • the brush storage section 60a is formed so that the brush 40 can rotate once along the brush storage section 60a. Therefore, the arc circle of the side wall surface of the first side wall 61, the arc circle of the side wall surface of the second side wall 62, the arc circle of the first side surface 41 of the brush 40, and the arc circle of the second side surface 42 of the brush 40 are concentric circles.
  • a gap exists between the first side wall 61 and the first side surface 41 of the brush 40.
  • a strip-shaped wire material drawn out from the spiral portion 51 of the brush spring 50 is in contact with the first side surface 41 of the brush 40.
  • a gap exists between the wire material of the brush spring 50 and the first side wall 61.
  • a gap may exist between the second side wall 62 and the second side surface 42 of the brush 40.
  • the gap between the first side wall 61 and the first side surface 41 of the brush 40, and the gap between the second side wall 62 and the second side surface 42 of the brush 40 are, for example, 100 ⁇ m or more.
  • the brush holder 60 has a third side wall 64.
  • the third side wall 64 is a wall provided along the commutator 30.
  • the third side wall 64 has an arc shape when viewed from above.
  • the third side wall 64 is provided in a portion of the commutator 30 facing the second side surface 42 (the side surface on the inner circumference side) of the brush 40.
  • the third side wall 64 is not provided in a portion of the commutator 30 that does not face the second side surface 42 of the brush 40.
  • the third side wall 64 is provided on the inner circumference side of the brush 40, but not on the outer circumference side of the brush 40.
  • a terminal 70 is attached to the brush holder 60. As shown in FIG. 4, the terminal 70 is formed so that it has a pair of legs and a cross-sectional shape that is substantially U-shaped. As shown in FIG. 9, the brush holder 60 is provided with a pair of slit-shaped through holes 65. The terminal 70 is fixed to the brush holder 60 by pressing the pair of legs of the terminal 70 into the pair of through holes 65 provided in the brush holder 60.
  • the terminal 70 is a conductive terminal made of a conductive metallic material.
  • the terminal 70 is a metal terminal made of a metal plate.
  • the terminal 70 receives the power passed through the coil 22 of the rotor 20 via the brush 40.
  • the terminal 70 is a power supply terminal.
  • the terminal 70 is electrically connected to an external power supply arranged outside the electric motor 1, and receives power supply power from the external power supply. Therefore, power is supplied to the terminal 70 from the external power supply.
  • the external power supply is a power supply that exists outside the electric motor 1.
  • the external power supply supplies a predetermined input voltage to the electric motor 1.
  • the external power supply is a DC power supply that supplies an input voltage of DC 12V to the electric motor 1. Therefore, the terminal 70 receives the DC voltage as the input voltage. For this reason, as shown in Figures 5A to 7, the electric motor 1 is provided with two terminals 70 as a pair of power supply terminals. In this case, one of the two terminals 70 is a positive terminal (plus terminal) that is connected to the positive side of the DC power supply. The other of the two terminals 70 is a negative terminal (minus terminal) that is connected to the negative side of the DC power supply.
  • the terminal 70 is located inside the arc-shaped brush 40. In other words, the terminal 70 is located between the second side surface 42 of the brush 40 and the commutator 30. Specifically, the terminal 70 is disposed in the space surrounded by the second side surface 42 of the brush 40 and the third side wall 64.
  • the terminal 70 is disposed in the center of the area surrounded by the brush 40. Specifically, when viewed from above, at least a portion of the terminal 70 overlaps with the center of the circle that constitutes the arc of the brush 40, which has an arc-shaped shape when viewed from above.
  • the pair of terminals 70 and the pair of brushes 40 are in one-to-one correspondence. In other words, one of the pair of terminals 70 is located inside one of the pair of brushes 40, and the other of the pair of terminals 70 is located inside the other of the pair of brushes 40.
  • electronic components such as a capacitor and a choke coil may be arranged in the brush holder 60. Such electronic components are electrically connected to the brush 40 and the terminal 70.
  • one or more capacitors may be connected in parallel to the two terminals 70. This allows the capacitors to suppress noise generated by the motor 1.
  • one lead of the capacitor is electrically connected to one of the two terminals 70, and the other lead of the capacitor is electrically connected to the other of the two terminals 70.
  • a choke coil may be inserted in the current path between the brush 40 and the terminal 70. This allows the choke coil to remove noise contained in the current flowing in the current path between the brush 40 and the terminal 70.
  • the choke coil is inserted, for example, between the terminal 70 and the conductive wire 80. In this case, one end of the choke coil is electrically connected to the terminal 70, and the other end of the choke coil is electrically connected to the conductive wire 80.
  • the electronic components electrically connected to the brush 40 and the terminal 70 may be arranged inside the arc-shaped brush 40 in the brush holder 60, similar to the terminal 70. Specifically, the electronic components are arranged in the space surrounded by the second side surface 42 and the third side wall 64 of the brush 40. The electronic components do not have to be arranged inside the brush 40. For example, the electronic components may be arranged in the space between two brushes 40.
  • the electronic components arranged in the brush holder 60 are not limited to noise removal elements such as choke coils or capacitors.
  • the brush 40 and the terminal 70 are electrically connected by a conductive wire 80.
  • a current supplied from the terminal 70 flows through the conductive wire 80.
  • the conductive wire 80 is a power supply line for supplying power to the brush 40.
  • a pigtail wire can be used as the conductive wire 80.
  • the first end 80a which is one end of the conductive wire 80, is connected to the brush 40.
  • the first end 80a of the conductive wire 80 is fixed to the rear end of the brush 40.
  • a step portion having a step surface that is one step lower is formed on the upper surface of the rear end of the brush 40.
  • the first end 80a of the conductive wire 80 is fixed to the step surface of this step portion.
  • the first end 80a of the conductive wire 80 is fixed to the brush 40 by being embedded in the brush 40.
  • the other end of the conductive wire 80, the second end 80b, is electrically connected to the terminal 70.
  • the second end 80b of the conductive wire 80 is directly connected to the terminal 70.
  • the second end 80b of the conductive wire 80 and the terminal 70 are joined by welding, soldering, or the like.
  • the conductive wire 80 is pre-twisted before the brush 40 wears.
  • the conductive wire 80 is configured so that the twist is relaxed as the brush 40 wears. Therefore, when joining the conductive wire 80 to the terminal 70, the conductive wire 80 is twisted multiple times and the second end 80b of the conductive wire 80 is joined to the terminal 70. Specifically, the conductive wire 80 is configured so that the twist is eliminated when the brush 40 wears down to its shortest length.
  • Figure 10 is a perspective view of the brush spring 50 in a state where the strip-shaped wire is stored in the spiral portion 51 (before the wire is pulled out).
  • Figure 11 is a diagram showing the brush spring 50 in the state shown in Figure 10 and the brush 40 when set in the brush holder 60.
  • Figure 12 is a diagram for explaining the state when the brush 40 and brush spring 50 are fixed to the brush holder 60.
  • the brush spring 50 is omitted in Figure 12.
  • the brush spring 50 and the brush 40 in the state shown in Figure 10 are set in the brush holder 60.
  • the wire that constitutes the brush spring 50 is inserted into the fixing portion 60b (notched groove) of the brush holder 60, and the tip of the V-shaped bent portion formed on the outer end portion 50a of the brush spring 50 is engaged with the outer surface of the first side wall 61 of the brush storage portion 60a, and the brush spring 50 is set in the brush storage portion 60a.
  • the brush 40 with the conductive wire 80 connected thereto is prepared, and the brush 40 is set in the brush storage section 60a with the rear end surface 44 of the brush 40 abutting against the spiral portion 51 of the brush spring 50. At this time, part of the brush 40 protrudes from the brush storage section 60a. Specifically, part of the brush 40 is present in the area where the commutator 30 is located (the area closer to the center than the third side wall 64). At this time, the conductive wire 80 connected to the brush 40 is joined to the terminal 70. The conductive wire 80 is joined to the terminal 70 as described above.
  • the brush 40 is moved from the state shown in Figure 11. Specifically, as shown in (d) of Figure 12, the brush 40 is moved until the front end surface 43 of the brush 40 is positioned at the front end of the brush storage section 60a.
  • the brush storage section 60a is formed so that the brush 40 can rotate once along the brush storage section 60a. This allows the rear end surface 44 of the brush 40 to be moved sequentially toward the back side of the brush storage section 60a (in the direction of the arrow in FIG. 12) by rotating the brush 40.
  • the conductive wire 80 is in a twisted state.
  • the spiral portion 51 of the brush spring 50 which abuts against the rear end surface 44 of the brush 40, moves toward the rear side of the brush storage section 60a as the brush 40 moves.
  • the outer end portion 50a of the brush spring 50 is fixed to the fixed portion 60b of the brush holder 60, as the brush 40 rotates, the strip-shaped wire that constitutes the brush spring 50 is pulled out from the spiral portion 51 along the arc shape of the brush storage section 60a. In other words, the brush 40 rotates while receiving the spring elastic force from the spiral portion 51 of the brush spring 50.
  • the two brushes 40 and the two brush springs 50 are set in the brush holder 60, and then the two brushes 40 and the two brush springs 50 are attached to the second bracket 102.
  • the brush holder 60 and the second bracket 102 are separate entities. Therefore, even when multiple brushes 40 are placed on the brush holder 60, the brushes 40 can be attached to the second bracket 102 while being held by the brush holder 60. This makes it possible to easily set multiple brushes 40 in the brush holder 60, even when multiple arc-shaped brushes 40 are used.
  • the current (drive current) supplied to the brushes 40 flows through the coils 22 via the commutator segments 31 of the commutator 30.
  • This generates magnetic flux in the rotor 20 (coils 22).
  • the magnetic force generated by the interaction between the magnetic flux generated in the rotor 20 and the magnetic flux generated from the stator 10 becomes torque that rotates the rotor 20.
  • the direction of the current flow is switched depending on the positional relationship when the commutator segments 31 of the commutator 30 come into contact with the brushes 40. In this way, by switching the direction of the current flow, a rotational force in a fixed direction is generated by the repulsive and attractive forces of the magnetic forces generated between the stator 10 and the rotor 20. This causes the rotor 20 to rotate around the rotating shaft 21.
  • Figure 13 shows how the brush 40 slides due to wear.
  • the brush 40 stored in the brush storage section 60a of the brush holder 60 is pressed against the commutator 30 by the brush spring 50. Therefore, when the rotor 20 rotates, the front end portion is worn down due to friction with the commutator segments 31 of the commutator 30. In other words, as shown by the arrow in Figure 13, the brush 40 becomes shorter due to wear. Therefore, the rear end surface 44 of the brush 40 moves toward the commutator 30 inside the brush storage section 60a.
  • the wire that constitutes the brush spring 50 which is a constant-load spring, is wound up into a spiral portion 51 as the brush 40 becomes shorter due to wear. In other words, the spiral portion 51 approaches the outer end portion 50a.
  • the brush 40 slides within the brush storage section 60a toward the commutator 30 as the front end wears.
  • the brush storage section 60a is composed of a first side wall 61 and a second side wall 62. Therefore, the brush 40 moves between the first side wall 61 and the second side wall 62 while being guided by the first side wall 61 and the second side wall 62.
  • the first side wall 61 and the second side wall 62 function as guide walls that guide the brush 40.
  • the spiral portion 51 of the brush spring 50 pressing against the brush 40 also moves between the first side wall 61 and the second side wall 62 toward the commutator 30.
  • the spiral portion 51 of the brush spring 50 moves between the first side wall 61 and the second side wall 62 while being guided by the first side wall 61 and the second side wall 62.
  • the first side wall 61 and the second side wall 62 also function as guide walls that guide the spiral portion 51 of the brush spring 50.
  • the brushes 40 are arc-shaped.
  • the terminals 70 attached to the brush holder 60 are located on the inside of the brushes 40.
  • This configuration allows the length of the conductive wire 80 that electrically connects the terminal 70 and the brush 40 to be shortened. Therefore, even if the conductive wire 80 moves as the brush 40 wears, it is possible to prevent the conductive wire 80 from interfering with the uneven structure of the brush holder 60, etc., and reducing the load stability of the brush 40. Therefore, it is possible to realize a highly reliable, long-life electric motor 1.
  • the terminal 70 overlaps with the center of the circle that constitutes the arc of the brush 40.
  • This configuration allows the length of the conductive wire 80 to be minimized. This further prevents the load stability of the brush 40 from decreasing.
  • a constant load spring is used as the brush spring 50 to press the brush 40 against the commutator 30.
  • a torsion spring When a torsion spring is used as a brush spring, the difference between the pressure (initial pressure) before the brush wears out and the pressure (final pressure) when the motor reaches the end of its life due to brush wear becomes large. In other words, the difference in the pressing load on the commutator becomes large between the initial and final stages of the brush's life. Furthermore, when a torsion spring presses an arc-shaped brush, the arc-shaped brush is pressed outward by the pressing load of the torsion spring. As a result, the pressing load when the brush presses the commutator by the torsion spring is reduced.
  • the torsion spring when a torsion spring is used as a brush spring for pressing an arc-shaped brush against a commutator, the torsion spring is positioned inside the arc-shaped brush. This leaves no free space inside the brush. This makes it difficult to position terminals inside the brush.
  • a constant load spring as the brush spring 50, a constant pressure load can be applied to the brush 40 by the brush spring 50 even if the brush 40 wears. This makes it possible to reduce the difference between the pressure (initial pressure) before the brush 40 wears and the pressure (final pressure) when the motor 1 reaches the end of its life due to wear of the brush 40.
  • the brush spring 50 is positioned so that the strip-shaped wire pulled out from the spiral portion 51 contacts the arc-shaped side of the brush 40.
  • the brush 40 not only receives a pressure load from the brush spring 50 at the rear end surface 44 where the spiral portion 51 contacts, but also at the contact point between the strip-shaped wire pulled out from the spiral portion 51 and the arc-shaped side of the brush 40. Therefore, it is possible to eliminate the reduction in the pressure load when the brush presses against the commutator, as occurs when a torsion spring is used as the brush spring.
  • the brush spring 50 is arranged so that the strip-shaped wire material (metal plate) that constitutes the brush spring 50 is in contact with the first side surface 41 on the outer periphery of the brush 40.
  • the strip-shaped wire pulled out from the spiral portion 51 of the brush spring 50 and the arc-shaped first side surface 41 of the brush 40 are in close contact with each other. Therefore, wear powder from the brush 40 cannot get between the strip-shaped wire of the brush spring 50 and the first side surface 41 of the brush 40. As a result, even when the brush spring 50 is used, the wear powder from the brush 40 does not reduce the sliding properties between the brush spring 50 and the brush 40.
  • the conductive wire 80 connected to the terminal 70 and brush 40 moves with the joint between the conductive wire 80 and the terminal 70 as a fixed end as the brush 40 wears.
  • the conductive wire 80 rotates with the joint between the conductive wire 80 and the terminal 70 as a fixed end.
  • the conductive wire 80 twists as the brush 40 wears, which may cause the load of the brush 40 to decrease.
  • the conductive wire 80 is twisted in advance before the brush 40 wears. This allows the twist to be relaxed as the brush 40 wears.
  • a third side wall 64 is provided along the commutator 30. This makes it possible to prevent brush wear powder from scattering.
  • the third side wall 64 functions as a protective wall that prevents brush wear powder from scattering. In this way, by providing the third side wall 64 on the brush holder 60, it is possible to prevent the load of the brush 40 from decreasing due to clogging with brush wear powder.
  • the third side wall 64 is provided in the portion facing the second side surface 42 of the brush 40 (the inner peripheral portion of the brush 40), and is not provided in the portion not facing the second side surface 42 of the brush 40 (the outer peripheral portion of the brush 40).
  • This can encourage the scattering of brush wear powder to the portion not facing the second side surface 42 of the brush 40.
  • This makes it difficult for brush wear powder to scatter to the portion facing the second side surface 42 of the brush 40.
  • the brush wear powder can be selectively collected to the outer peripheral portion of the brush 40. Therefore, it is possible to prevent the insulation reliability of the terminals 70 and electronic components arranged in the inner peripheral portion of the brush 40 from being reduced by the brush wear powder. For example, it is possible to prevent the electronic components from shorting out, etc., and thereby reducing the electromagnetic compatibility (EMC).
  • EMC electromagnetic compatibility
  • the arc-shaped brush 40 is made without cutting.
  • a sintered body obtained by compressing and sintering powder is cut.
  • the manufacturing costs are high to make an arc-shaped brush 40 with high dimensional accuracy. Therefore, in this embodiment, the arc-shaped brush 40 is made without cutting. This allows the brush 40 to be made at low cost. Therefore, a low-cost electric motor 1 can be realized.
  • the motor 1 also uses a long, arc-shaped brush 40. Specifically, the angle between the line connecting the center point of the circle that forms the arc of the brush 40 to the front end surface 43 of the brush 40 and the line connecting the center point of the circle that forms the arc of the brush 40 to the rear end surface 44 of the brush 40 is 90° or more.
  • a torsion spring is used as the brush spring for such a long, arc-shaped brush 40
  • the pressing load applied to the brush 40 by the brush spring may not be stable, resulting in a reduced lifespan and quality.
  • the pressing load on the brush 40 can be stabilized even when a long, arc-shaped brush 40 is used. This makes it possible to realize an electric motor 1 with a long lifespan and high quality.
  • the electric motor 1 includes the rotating shaft 21 whose axial direction is the direction in which the axis C extends, the commutator 30 attached to the rotating shaft 21, the brush 40 in contact with the commutator 30, the brush holder 60 that holds the brush 40, the terminal 70 attached to the brush holder 60, and a conductive wire having one end connected to the brush 40 and the other end electrically connected to the terminal.
  • the brush 40 is arc-shaped.
  • the terminal 70 is located inside the brush 40.
  • FIG. 14 is a top view of a brush holder 60 in which brushes 40A and brush springs 50 are arranged in an electric motor 1A according to a second embodiment.
  • Fig. 15 is an enlarged view of a contact point between a front end surface 43 of brush 40A and commutator 30 and the surrounding area in Fig. 14.
  • the angle between the tangent of the brush 40 and the direction of rotation of the electric motor 1 is 90° (see the enlarged portion in FIG. 5B).
  • the angle ⁇ (see FIG. 15) between the tangent of the brush 40A and the direction of rotation of the electric motor 1 is less than 90°. It is preferable that the angle ⁇ be greater than 45°. In other words, it is preferable that the angle ⁇ be 45° ⁇ 90°.
  • the configuration of the electric motor 1A in this embodiment is basically the same as the electric motor 1 in the above-mentioned embodiment 1.
  • this embodiment also provides the same effects as the electric motor 1 in the first embodiment.
  • the terminal 70 is located inside the arc-shaped brush 40A, so that it provides the effect of preventing the load stability of the brush 40A from decreasing.
  • the angle ⁇ between the tangent of brush 40A and the direction of rotation of electric motor 1 is less than 90°.
  • This configuration allows the diameter of the circle forming the arc of brush 40A to be increased.
  • the length of brush 40A can be made longer than the length of brush 40 in the first embodiment above. This allows the life of motor 1A to be extended. In this case, by arranging the longer brush 40A to effectively utilize the internal space of motor 1A, the life of motor 1A can be extended without increasing the external dimensions of motor 1A. In other words, a compact motor 1A with a long life can be realized.
  • the load will be strong on the second side 42 (inner peripheral surface) of the brush 40A, and the load on the brush 40 will be biased.
  • a constant load spring is used as the brush spring 50, the load will be biased on the first side 41 (outer peripheral surface) of the brush 40A. Therefore, by making the angle ⁇ between the tangent of the brush 40A and the direction of rotation of the motor 1 less than 90°, the load on the front and rear ends of the brush 40A can be made closer to constant. This makes it possible to apply a load appropriate for the commutator 30 to the commutator 30.
  • FIG. 16 is a perspective view of a brush holder 60 in which a brush 40B and a brush spring 50 are arranged in the electric motor 1B according to the third embodiment.
  • Fig. 17 is an enlarged view of a rear end portion of the brush 40B and its surrounding area in Fig. 16.
  • Fig. 18 is a perspective view of the brush 40B and conductive wire 80 provided in the electric motor 1B according to the third embodiment.
  • the electric motor 1B differs from the electric motor 1 according to the first embodiment in the shape of the brush 40B and the connection structure between the brush 40B and the brush spring 50.
  • brush 40B has protrusion 45 and groove 46.
  • Spiral portion 51 of brush spring 50 is inserted into protrusion 45.
  • the groove 46 is fitted with the wound portion of wire in spiral portion 51 inserted into protrusion 45 (laminated portion of wire).
  • spiral portion 51 of brush spring 50 is wound around protrusion 45 of brush 40B.
  • the protrusion 45 of the brush 40B is formed on the upper surface of the rear end of the brush 40B.
  • the protrusion 45 is formed in a cylindrical shape.
  • the shape of the protrusion 45 when viewed from above is circular.
  • the central axis of the cylindrical protrusion 45 is parallel to the axis C of the rotating shaft 21.
  • the conductive wire 80 is fixed to the center of the protrusion 45. Therefore, when viewed from above, the connection portion between the brush 40B and the conductive wire 80 is located inside the spiral portion 51 of the brush spring 50.
  • the groove 46 is formed on the front side of the protrusion 45.
  • the brush spring 50 thus arranged on the brush 40B applies pressure to the brush 40B on the inner circumferential surface of the spiral portion 51. Specifically, the brush spring 50 applies pressure to the brush 40B on the inner circumferential surface of the spiral portion 51 on the rear end surface 44 side of the brush 40B.
  • the configuration of the electric motor 1B is basically the same as that of the electric motor 1 in the first embodiment described above.
  • the electric motor 1B has the same effect as the electric motor 1 in the first embodiment.
  • the terminal 70 is also located inside the arc-shaped brush 40B. This has the effect of preventing the load stability of the brush 40B from decreasing.
  • the brush spring 50 which is a constant force spring, is also positioned so that it contacts the first side surface 41 (the side surface on the outer periphery) of the brush 40B.
  • the brush spring 50 were arranged so as to contact the second side surface 42 (the side surface on the inner circumference) of the brush 40B, when the outer diameter of the spiral portion 51 increases as the brush 40B wears and the band-shaped wire material constituting the brush spring 50 undergoes plastic deformation, the amount of plastic deformation would be more than doubled. Therefore, it is possible to increase the width W of the groove 46 of the brush 40B. However, if the width W of the groove 46 is made too large, the effective wear length of the brush 40B will be reduced.
  • the amount of plastic deformation of the band-shaped wire material constituting the brush spring 50 can be reduced without increasing the width W of the groove 46 of the brush 40B too much.
  • the width W of the groove 46 should be between 1.3 and 2 times the thickness of the portion of the spiral portion 51 where the wire is wound. This allows the amount of plastic deformation of the strip-shaped wire that makes up the brush spring 50 to be about 1.5 times larger.
  • the brush spring 50 which is a constant-load spring, applies pressure to the brush 40B with the inner circumferential surface of the spiral portion 51.
  • the brush spring 50 has a connection portion between the brush 40B and the conductive wire 80 located inside the spiral portion 51.
  • This configuration maximizes the effective wear length of the brush 40B. It also stabilizes the pressure (spring load) applied by the brush 40B to the commutator 30. Moreover, the brush spring 50 can be connected to the brush 40B by inserting and fitting the spiral portion 51 of the brush spring 50 into the protrusion 45 of the brush 40B, so that the brush 40B can be easily set in the brush holder 60.
  • FIG. 19 is a diagram for explaining the arrangement of the brushes 40 in the electric motor 1C according to the modified example.
  • four arc-shaped brushes 40 may be arranged.
  • a torsion spring is used as the brush spring, it is difficult to arrange four arc-shaped brushes due to space issues unless the external size of the electric motor is increased.
  • a constant-load spring as the brush spring 50 and arranging the terminal 70 inside the arc-shaped brush 40, as shown in FIG.
  • four arc-shaped brushes 40 can be arranged without increasing the external size of the electric motor 1C.
  • the space of the electric motor 1 can be effectively utilized to further extend the life of the electric motor 1.
  • the four brushes 40 may be arranged at equal intervals (0°, 90°, 180°, 270°) in the rotation direction. This allows the space of the electric motor 1C to be used as effectively as possible.
  • the longest-lasting motor 1C can be achieved by using four brushes 40.
  • the number of poles of the motor 1C can be 4n (n is an integer equal to or greater than 1).
  • the electric motors 1 to 1B are coreless motors in which the stator 10 and the rotor 20 do not have cores.
  • the electric motor 1 may be an electric motor in which the stator 10 and the rotor 20 have cores.
  • the stator 10 is composed of only permanent magnets.
  • the stator 10 may be a stator composed of a permanent magnet and an iron core, or an armature composed of a stator winding and an iron core without using permanent magnets.
  • the electric motors 1 to 1B are flat motors with an outer size whose thickness is smaller than the outer diameter.
  • this is not limited to this.
  • the technology disclosed herein can also be applied to, for example, a cylindrical electric motor having a cylindrical housing with an outer size whose thickness is larger than the outer diameter.
  • the direction of the main magnetic flux generated by the stator 10 and the rotor 20 is the direction of the axis C of the rotating shaft 21.
  • the direction of the main magnetic flux generated by the stator 10 and the rotor 20 may be a direction perpendicular to the direction of the axis C of the rotating shaft 21 (the radial direction of the rotation of the rotating shaft 21).
  • the technology disclosed herein can also be applied to an inner rotor type motor in which the rotor 20 is arranged inside the stator 10.
  • the electric motors 1 to 1B are vehicle motors used in vehicles. However, this is not limited to this.
  • the technology disclosed herein can also be applied to electric motors used in various other electrical devices, such as electric motors used in electric blowers mounted on electric vacuum cleaners, etc.
  • this disclosure also includes forms obtained by applying various modifications that a person skilled in the art would conceive of to the above-mentioned embodiments 1 to 3 and modifications, or forms realized by arbitrarily combining the components and functions of embodiments 1 to 3 and modifications without departing from the spirit of this disclosure.
  • this disclosure also includes any combination of one or more components in each of the multiple claims described in the claims at the time of filing this application.
  • a cited-form claim described in the claims at the time of filing this application is made into a multiple claim or multiple-multi claim so as to cite any multiple claims, this disclosure also includes inventions of combinations of all claims included in that multiple claim or multiple-multi claim.
  • the technology disclosed herein can be widely used in a variety of products equipped with electric motors, including products in the electrical equipment field such as automobiles and in the field of household electrical appliances.

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Abstract

This electric motor comprises: a rotary shaft, the axial direction of which is the direction in which the axis thereof extends; a commutator that is attached to the rotary shaft; a brush that is in contact with the commutator; a brush holder that holds the brush; a terminal that is attached to the brush holder; and a conductive wire that has one end connected to the brush and the other end electrically connected to the terminal. The brush has an arc shape, and the terminal is positioned inward of the brush.

Description

電動機Electric motor
　本開示は、電動機に関する。 This disclosure relates to electric motors.
　電動機は、電気掃除機等の家庭用電気機器分野をはじめとして、自動車等の電装分野等にも広く用いられている。例えば、二輪又は四輪の車両には、ラジエータ等の冷却ファンを駆動するために電動機が用いられている。 Electric motors are widely used in household electrical appliances such as vacuum cleaners, as well as in the electrical equipment field of automobiles. For example, electric motors are used in two-wheeled and four-wheeled vehicles to drive cooling fans such as radiators.
　電動機としては、ブラシを用いるブラシ付き電動機（整流子電動機）、及び、ブラシを用いないブラシレス電動機が知られている。このうち、ブラシ付き電動機は、固定子と、回転子と、整流子と、ブラシと、ブラシホルダと、ブラシバネとを備える。回転子は、固定子の磁力によって回転する。整流子は、回転子の回転軸に取り付けられる。ブラシは、整流子に摺接する。ブラシホルダは、ブラシを保持する。ブラシバネは、ブラシを整流子に押し当てる。 Known electric motors include brushed motors (commutator motors) that use brushes, and brushless motors that do not use brushes. Of these, brushed motors include a stator, rotor, commutator, brushes, a brush holder, and a brush spring. The rotor rotates due to the magnetic force of the stator. The commutator is attached to the rotating shaft of the rotor. The brushes are in sliding contact with the commutator. The brush holder holds the brushes. The brush spring presses the brushes against the commutator.
　ブラシ付き電動機では、電動機の長寿命化を図るために、ブラシの長さを長くすることが考えられる。しかしながら、直線状のブラシを単純に長くすると、電動機の直径が大きくなって電動機が大型化する。そこで、電動機の長寿命化と小型化との両立を図るために、円弧状のブラシを用いる技術が提案されている（例えば、特許文献１、２を参照）。 In brushed motors, it is possible to lengthen the brushes in order to extend the life of the motor. However, simply lengthening the straight brushes increases the diameter of the motor, resulting in a larger motor. Therefore, technology has been proposed that uses arc-shaped brushes in order to achieve both a longer life and a more compact motor (see, for example, Patent Documents 1 and 2).
　ブラシ付き電動機は、ブラシに供給する電力を外部電源から受ける電源端子と、ブラシと電源端子とを電気的に接続する導電線とを備える。導電線は、一方の端部がブラシに固定され、他方の端部が電源端子と電気的に接続される。導電線としては、例えば、ピグテール線が用いられる。 A brushed electric motor has a power supply terminal that receives power from an external power source to be supplied to the brushes, and a conductive wire that electrically connects the brushes and the power supply terminal. One end of the conductive wire is fixed to the brush, and the other end is electrically connected to the power supply terminal. For example, a pigtail wire is used as the conductive wire.
　ブラシと電源端子とを接続する導電線は、ブラシが摩耗して短くなるにしたがって、電源端子に接続された端部を固定端として移動する。このとき、導電線は、移動するにつれて、たるむ等して形状が変化する。 The conductive wire connecting the brush and the power terminal moves with the end connected to the power terminal as the brush wears and becomes shorter. As the conductive wire moves, it sags, changing shape, etc.
　さらに、円弧状のブラシを備える電動機では、円弧状のブラシは長いので、ブラシと電源端子とを接続する導電線の長さも長くなる。このため、円弧状のブラシに接続された導電線は、ブラシが摩耗して短くなると、たるみやすい。つまり、円弧状のブラシに接続された導電線は、動きが大きくなる。 Furthermore, in electric motors equipped with arc-shaped brushes, the arc-shaped brushes are long, so the length of the conductive wires connecting the brushes to the power terminals is also long. For this reason, the conductive wires connected to the arc-shaped brushes are prone to sagging when the brushes wear and become shorter. In other words, the conductive wires connected to the arc-shaped brushes move more.
　ブラシと電源端子とを接続する導電線は、ブラシとともにブラシホルダに配置される。この場合、ブラシホルダには、ブラシ収納部等の大小様々な凹凸構造が存在する。したがって、ブラシホルダに配置された導電線は、ブラシの摩耗とともに動いていくと、ブラシホルダの凹凸構造に干渉することがある。この結果、ブラシバネによって、ブラシが整流子を押し付ける際の押圧荷重が減少する等の不具合が生じることがある。つまり、ブラシの荷重安定性が低下する。 The conductive wires connecting the brushes and the power terminals are placed in the brush holder together with the brushes. In this case, the brush holder has uneven structures of various sizes, such as brush storage areas. Therefore, when the conductive wires placed in the brush holder move as the brushes wear, they can interfere with the uneven structure of the brush holder. This can result in problems such as a reduction in the pressure load when the brush presses against the commutator due to the brush spring. In other words, the load stability of the brush is reduced.
　このようにブラシの荷重安定性が低下すると、ブラシの有効摩耗部が残っているにもかかわらず、ブラシと整流子との導通不良等の不具合が発生し、電動機としての機能を失ってしまうことがある。つまり、電動機の寿命が短くなる。 When the load stability of the brush decreases in this way, even if the effective wear portion of the brush remains, problems such as poor electrical continuity between the brush and the commutator can occur, causing the motor to lose its functionality. In other words, the lifespan of the motor is shortened.
特開２００６－１４９１５４号公報JP 2006-149154 A 特開２０１０－３５２７２号公報JP 2010-35272 A
　本開示は、このような問題を解決するためになされたものである。本開示は、円弧状のブラシを用いた電動機であっても、ブラシに接続された導電線によってブラシの荷重安定性が低下してしまうことを抑制できる電動機を提供することを目的とする。 The present disclosure has been made to solve such problems. The purpose of the present disclosure is to provide an electric motor that can prevent the load stability of the brush from being reduced due to the conductive wire connected to the brush, even in a motor that uses an arc-shaped brush.
　上記目的を達成するために、本開示に係る電動機の一態様は、軸心が延伸する方向を軸心方向とする回転軸と、前記回転軸に取り付けられた整流子と、前記整流子に接するブラシと、前記ブラシを保持するブラシホルダと、前記ブラシホルダに取り付けられた端子と、一方の端部が前記ブラシに接続され、他方の端部が前記端子と電気的に接続された導電線と、を備え、前記ブラシは、円弧状であり、前記端子は、前記ブラシの内側に位置している。 In order to achieve the above object, one embodiment of the electric motor according to the present disclosure comprises a rotating shaft whose axial direction is the direction in which the shaft extends, a commutator attached to the rotating shaft, a brush in contact with the commutator, a brush holder that holds the brush, a terminal attached to the brush holder, and a conductive wire having one end connected to the brush and the other end electrically connected to the terminal, the brush being arc-shaped, and the terminal being located inside the brush.
　本開示によれば、円弧状のブラシを用いた電動機であっても、ブラシに接続された導電線によってブラシの荷重安定性が低下してしまうことを抑制できる。 According to the present disclosure, even in an electric motor that uses arc-shaped brushes, it is possible to prevent the load stability of the brushes from being reduced due to the conductive wires connected to the brushes.
図１は、実施の形態１に係る電動機を斜め上方から見たときの外観斜視図である。FIG. 1 is an external perspective view of an electric motor according to a first embodiment of the present invention, as viewed obliquely from above. 図２は、実施の形態１に係る電動機を斜め下方から見たときの外観斜視図である。FIG. 2 is an external perspective view of the electric motor according to the first embodiment as viewed obliquely from below. 図３は、実施の形態１に係る電動機の断面斜視図である。FIG. 3 is a cross-sectional perspective view of the electric motor according to the first embodiment. 図４は、実施の形態１に係る電動機の分解斜視図である。FIG. 4 is an exploded perspective view of the electric motor according to the first embodiment. 図５Ａは、実施の形態１に係る電動機において、各種部品が配置されたブラシホルダと整流子とを示す上面図である。FIG. 5A is a top view showing a brush holder in which various components are arranged and a commutator in the electric motor according to the first embodiment. 図５Ｂは、実施の形態１に係る電動機において、整流子とブラシとブラシバネとの関係を示す図である。FIG. 5B is a diagram showing the relationship between the commutator, the brushes, and the brush springs in the electric motor according to embodiment 1. 図６は、実施の形態１に係る電動機において、各種部品が配置されたブラシホルダと整流子とを示す斜視図である。FIG. 6 is a perspective view showing a brush holder in which various components are arranged and a commutator in the electric motor according to the first embodiment. 図７は、図６において、一対のブラシと一対のブラシバネと整流子との位置関係を示す斜視図である。FIG. 7 is a perspective view showing the positional relationship between the pair of brushes, the pair of brush springs, and the commutator in FIG. 図８は、図７において、１つブラシと１つのブラシバネと整流子との位置関係を示す上面図である。FIG. 8 is a top view showing the positional relationship between one brush, one brush spring, and a commutator in FIG. 図９は、実施の形態１に係る電動機におけるブラシホルダの斜視図である。FIG. 9 is a perspective view of a brush holder in the electric motor according to the first embodiment. 図１０は、帯状の線材が渦巻部に収納された状態のブラシバネの斜視図である。FIG. 10 is a perspective view of the brush spring in a state where the strip-shaped wire is housed in the spiral portion. 図１１は、図１０の状態のブラシバネとブラシとをブラシホルダにセットしたときの様子を示す図である。FIG. 11 is a diagram showing a state in which the brush spring and the brush in the state shown in FIG. 10 are set in the brush holder. 図１２は、ブラシ及びブラシバネをブラシホルダに固定するときの様子を説明するための図である。FIG. 12 is a diagram for explaining a state in which the brush and the brush spring are fixed to the brush holder. 図１３は、摩耗によりブラシが摺動する様子を示す図である。FIG. 13 is a diagram showing how the brush slides due to wear. 図１４は、実施の形態２に係る電動機において、ブラシ及びブラシバネが配置されたブラシホルダの上面図である。FIG. 14 is a top view of a brush holder in which brushes and brush springs are arranged in the electric motor according to the second embodiment. 図１５は、図１４におけるブラシの前端面と整流子とが接触する箇所及びその周辺部分の拡大図である。FIG. 15 is an enlarged view of the contact point between the front end face of the brush and the commutator and the surrounding area in FIG. 図１６は、実施の形態３に係る電動機において、ブラシ及びブラシバネが配置されたブラシホルダの斜視図である。FIG. 16 is a perspective view of a brush holder in which brushes and brush springs are arranged in the electric motor according to the third embodiment. 図１７は、図１６におけるブラシの後端部及びその周辺部分の拡大図である。FIG. 17 is an enlarged view of the rear end portion of the brush and its surrounding area in FIG. 図１８は、実施の形態３に係る電動機が備えるブラシ及び導電線の斜視図である。FIG. 18 is a perspective view of a brush and conductive wires included in the electric motor according to the third embodiment. 図１９は、変形例に係る電動機におけるブラシの配置を説明するための図である。FIG. 19 is a diagram for explaining the arrangement of brushes in an electric motor according to a modified example.
　以下、本開示の実施の形態について、図面を参照しながら説明する。以下に説明する実施の形態は、いずれも本開示の一具体例を示すものである。したがって、以下の実施の形態で示される、数値、形状、材料、構成要素、構成要素の配置位置及び接続形態等は、一例であって本開示を限定する主旨ではない。よって、以下の実施の形態における構成要素のうち、本開示の最上位概念を示す独立請求項に記載されていない構成要素については、任意の構成要素として説明される。 Below, embodiments of the present disclosure will be described with reference to the drawings. Each embodiment described below shows a specific example of the present disclosure. Therefore, the numerical values, shapes, materials, components, arrangement positions of the components, connection forms, etc. shown in the following embodiments are merely examples and are not intended to limit the present disclosure. Therefore, among the components in the following embodiments, components that are not described in an independent claim that shows the highest concept of the present disclosure will be described as optional components.
　各図は、模式図であり、必ずしも厳密に図示されたものではない。各図において、実質的に他の図と同一の構成に対しては同一の符号を付しており、重複する説明は省略又は簡略化する。本明細書において、「上」及び「下」という用語は、必ずしも、絶対的な空間認識における上方向（鉛直上方）及び下方向（鉛直下方）を指すものではない。 Each figure is a schematic diagram and is not necessarily a precise illustration. In each figure, the same reference numerals are used for configurations that are substantially the same as in other figures, and duplicate explanations are omitted or simplified. In this specification, the terms "upper" and "lower" do not necessarily refer to the upper direction (vertically upward) and the lower direction (vertically downward) in an absolute spatial sense.
　（実施の形態１）
　まず、実施の形態１に係る電動機１の全体の構成について、図１～図６を用いて説明する。図１は、実施の形態１に係る電動機１を斜め上方から見たときの外観斜視図である。図２は、実施の形態１に係る電動機１を斜め下方から見たときの外観斜視図である。図３は、実施の形態１に係る電動機１の断面斜視図である。図４は、実施の形態１に係る電動機１の分解斜視図である。図５Ａは、実施の形態１に係る電動機１において、各種部品が配置されたブラシホルダ６０と整流子３０とを示す上面図である。図５Ｂは、実施の形態１に係る電動機１において、整流子３０とブラシ４０とブラシバネ５０との関係を示す図である。図６は、実施の形態１に係る電動機１において、各種部品が配置されたブラシホルダ６０と整流子３０とを示す斜視図である。 (Embodiment 1)
First, the overall configuration of the electric motor 1 according to the first embodiment will be described with reference to Figs. 1 to 6. Fig. 1 is an external perspective view of the electric motor 1 according to the first embodiment when viewed obliquely from above. Fig. 2 is an external perspective view of the electric motor 1 according to the first embodiment when viewed obliquely from below. Fig. 3 is a cross-sectional perspective view of the electric motor 1 according to the first embodiment. Fig. 4 is an exploded perspective view of the electric motor 1 according to the first embodiment. Fig. 5A is a top view showing the brush holder 60 and the commutator 30 on which various components are arranged in the electric motor 1 according to the first embodiment. Fig. 5B is a diagram showing the relationship between the commutator 30, the brushes 40, and the brush springs 50 in the electric motor 1 according to the first embodiment. Fig. 6 is a perspective view showing the brush holder 60 and the commutator 30 on which various components are arranged in the electric motor 1 according to the first embodiment.
　図１～図６に示すように、電動機１は、固定子１０（ステータ）と、固定子１０の磁力により回転する回転子２０（ロータ）とを備える。電動機１は、ブラシ付き電動機である。電動機１は、整流子３０と、少なくとも１つのブラシ４０と、ブラシバネ５０と、ブラシホルダ６０とを備える。整流子３０は、回転子２０が有する回転軸２１に取り付けられる。少なくとも１つのブラシ４０は、整流子３０に接する。ブラシバネ５０は、ブラシ４０を整流子３０に押し当てる。ブラシホルダ６０は、ブラシ４０を保持する。電動機１は、外部電源から電力を受ける端子７０と、端子７０及びブラシ４０と電気的に接続された導電線８０とを備える。電動機１は、さらに、第１軸受け９１及び第２軸受け９２と、第１ブラケット１０１及び第２ブラケット１０２とを備える。 As shown in Figs. 1 to 6, the electric motor 1 includes a stator 10 and a rotor 20 that rotates due to the magnetic force of the stator 10. The electric motor 1 is a brushed electric motor. The electric motor 1 includes a commutator 30, at least one brush 40, a brush spring 50, and a brush holder 60. The commutator 30 is attached to a rotating shaft 21 of the rotor 20. At least one brush 40 contacts the commutator 30. The brush spring 50 presses the brush 40 against the commutator 30. The brush holder 60 holds the brush 40. The electric motor 1 includes a terminal 70 that receives power from an external power source, and a conductive wire 80 that is electrically connected to the terminal 70 and the brush 40. The electric motor 1 further includes a first bearing 91, a second bearing 92, a first bracket 101, and a second bracket 102.
　電動機１は、直流により駆動する直流電動機（ＤＣモータ）の一種である。電動機１では、固定子１０として磁石が用いられている。電動機１では、回転子２０としてコイル２２を有する電機子が用いられている。電動機１は、二輪又は四輪等の車両に搭載される扁平型（フラット型）のブラシ付きコアレスモータ（フラットモータ）である。したがって、固定子１０及び回転子２０は、コア（鉄心）を有していない。電動機１は、全体として厚みが薄くて軽い構成になっている。具体的には、電動機１は、車両におけるラジエータの冷却ファンに用いられる小型モータである。電動機１は、例えばＤＣ１２Ｖの入力電圧により駆動する。 The electric motor 1 is a type of direct current motor (DC motor) that is driven by direct current. In the electric motor 1, a magnet is used as the stator 10. In the electric motor 1, an armature having a coil 22 is used as the rotor 20. The electric motor 1 is a flat type (flat type) brushed coreless motor (flat motor) that is mounted on a vehicle such as a two-wheeled or four-wheeled vehicle. Therefore, the stator 10 and the rotor 20 do not have a core (iron core). The electric motor 1 is configured to be thin and lightweight overall. Specifically, the electric motor 1 is a small motor used in a cooling fan for a radiator in a vehicle. The electric motor 1 is driven by an input voltage of, for example, DC 12V.
　以下、電動機１の各構成部材について詳細に説明する。 The components of the electric motor 1 are described in detail below.
　図３に示すように、固定子１０は、回転子２０との間に微小なエアギャップを介して配置されている。固定子１０は、回転子２０に作用する磁力を発生させる。固定子１０は、回転子２０とのエアギャップ面に磁束を生成する構成になっている。固定子１０は、電機子である回転子２０とともに磁気回路を構成している。図４に示すように、固定子１０は、全体として円環状である。固定子１０は、回転軸２１の周方向に沿って回転子２０とのエアギャップ面にＮ極とＳ極とが交互に均等に存在するように着磁されている。固定子１０は、トルクを発生するための磁束を作る界磁である。固定子１０は、例えば永久磁石によって構成されている。固定子１０（磁石）が発生する主磁束の向きは、回転軸２１が延伸する方向である。図３に示すように、固定子１０は、第１ブラケット１０１に固定されている。 As shown in FIG. 3, the stator 10 is disposed with a small air gap between it and the rotor 20. The stator 10 generates a magnetic force acting on the rotor 20. The stator 10 is configured to generate magnetic flux on the air gap surface with the rotor 20. The stator 10 forms a magnetic circuit together with the rotor 20, which is an armature. As shown in FIG. 4, the stator 10 is generally annular. The stator 10 is magnetized so that N poles and S poles are alternately and evenly present on the air gap surface with the rotor 20 along the circumferential direction of the rotating shaft 21. The stator 10 is a field magnet that creates magnetic flux to generate torque. The stator 10 is composed of, for example, a permanent magnet. The direction of the main magnetic flux generated by the stator 10 (magnet) is the direction in which the rotating shaft 21 extends. As shown in FIG. 3, the stator 10 is fixed to a first bracket 101.
　図３に示すように、回転子２０は、回転軸２１及びコイル２２を有する。回転子２０は、コアを有さないコアレス回転子である。 As shown in FIG. 3, the rotor 20 has a rotating shaft 21 and a coil 22. The rotor 20 is a coreless rotor that does not have a core.
　回転子２０は、回転軸２１の軸心Ｃを回転中心として回転する。回転子２０は、固定子１０に作用する磁力を発生させる。回転子２０が発生する主磁束の向きは、回転軸２１が延伸する方向である。 The rotor 20 rotates around the axis C of the rotating shaft 21. The rotor 20 generates a magnetic force that acts on the stator 10. The direction of the main magnetic flux generated by the rotor 20 is the direction in which the rotating shaft 21 extends.
　回転子２０は、固定子１０と対向して配置されている。回転子２０は、回転軸２１が延伸する方向において固定子１０と対向している。具体的には、回転子２０が含むコイル２２と固定子１０とは、回転軸２１が延伸する方向に対向している。 The rotor 20 is disposed opposite the stator 10. The rotor 20 faces the stator 10 in the direction in which the rotating shaft 21 extends. Specifically, the coils 22 contained in the rotor 20 and the stator 10 face each other in the direction in which the rotating shaft 21 extends.
　回転軸２１は、軸心Ｃを有するシャフトである。回転軸２１は、長尺状の棒状部材である。一例として、回転軸２１は、ＳＵＳ（Ｓｔｅｅｌ　ｓｐｅｃｉａｌ　Ｕｓｅ　Ｓｔａｉｎｌｅｓｓ）等の金属材料によって構成された金属棒である。回転軸２１の軸心Ｃは、回転子２０が回転する際の中心になる。回転軸２１の長手方向、すなわち回転軸２１が延伸する方向は、軸心Ｃの方向（軸心方向）である。 The rotating shaft 21 is a shaft having an axis C. The rotating shaft 21 is a long rod-shaped member. As an example, the rotating shaft 21 is a metal rod made of a metal material such as SUS (Steel special use stainless steel). The axis C of the rotating shaft 21 is the center when the rotor 20 rotates. The longitudinal direction of the rotating shaft 21, i.e., the direction in which the rotating shaft 21 extends, is the direction of the axis C (axial direction).
　回転軸２１の一方の端部である第１端部２１ａは、第１軸受け９１に支持されている。回転軸２１の他方の端部である第２端部２１ｂは、第２軸受け９２に支持されている。一例として、第１軸受け９１及び第２軸受け９２は、ボールベアリング等のベアリングである。 The first end 21a, which is one end of the rotating shaft 21, is supported by a first bearing 91. The second end 21b, which is the other end of the rotating shaft 21, is supported by a second bearing 92. As an example, the first bearing 91 and the second bearing 92 are bearings such as ball bearings.
　回転軸２１の第１端部２１ａは、出力側の端部（出力軸）である。回転軸２１の第１端部２１ａは、第１ブラケット１０１及び第１軸受け９１から突出している。第１端部２１ａには、例えば回転ファン等の負荷が取り付けられる。回転軸２１の第２端部２１ｂは、反出力側の端部（反出力軸）である。回転軸２１の第２端部２１ｂは、第２ブラケット１０２及び第２軸受け９２から突出していない。 The first end 21a of the rotating shaft 21 is the output side end (output shaft). The first end 21a of the rotating shaft 21 protrudes from the first bracket 101 and the first bearing 91. A load such as a rotating fan is attached to the first end 21a. The second end 21b of the rotating shaft 21 is the anti-output side end (anti-output shaft). The second end 21b of the rotating shaft 21 does not protrude from the second bracket 102 and the second bearing 92.
　第１軸受け９１は、第１ブラケット１０１に保持されている。具体的には、第１軸受け９１は、第１ブラケット１０１の中央部に設けられた凹部に固定されている。第２軸受け９２は、ブラシホルダ６０に保持されている。具体的には、第２軸受け９２は、ブラシホルダ６０の中央部に設けられた凹部に固定されている。 The first bearing 91 is held by the first bracket 101. Specifically, the first bearing 91 is fixed to a recess provided in the center of the first bracket 101. The second bearing 92 is held by the brush holder 60. Specifically, the second bearing 92 is fixed to a recess provided in the center of the brush holder 60.
　第１ブラケット１０１及び第２ブラケット１０２は、例えば、金属材料によって構成されている。例えば、第１ブラケット１０１及び第２ブラケット１０２は、冷間圧延鋼板（ＳＰＣ（Ｓｔｅｅｌ　Ｐｌａｔｅ　Ｃｏｌｄ）材）等の鉄系材料又はアルミニウム等の金属によって構成されている。第１ブラケット１０１及び第２ブラケット１０２の材質は、金属材料に限るものではなく、樹脂材料であってもよい。しかし、電動機１から発生するノイズを抑制するとの観点では、第１ブラケット１０１及び第２ブラケット１０２は、金属材料によって構成されているとよい。 The first bracket 101 and the second bracket 102 are made of, for example, a metal material. For example, the first bracket 101 and the second bracket 102 are made of an iron-based material such as cold-rolled steel plate (SPC (Steel Plate Cold) material) or a metal such as aluminum. The material of the first bracket 101 and the second bracket 102 is not limited to a metal material and may be a resin material. However, from the viewpoint of suppressing noise generated from the electric motor 1, it is preferable that the first bracket 101 and the second bracket 102 are made of a metal material.
　図１～図４に示すように、第１ブラケット１０１は、電動機１の外殻部材である。第１ブラケット１０１は、底部及び円筒状の側壁部を有する薄い扁平状の筒体である。第２ブラケット１０２は、貫通孔を有する平板である。第１ブラケット１０１とブラシホルダ６０とで外殻筐体が構成されている。この外殻筐体の中に、固定子１０と回転子２０とが配置されている。 As shown in Figures 1 to 4, the first bracket 101 is an outer shell member of the electric motor 1. The first bracket 101 is a thin, flat cylinder having a bottom and a cylindrical side wall. The second bracket 102 is a flat plate with a through hole. The first bracket 101 and the brush holder 60 form an outer shell housing. The stator 10 and rotor 20 are arranged inside this outer shell housing.
　図３に示すように、回転子２０は、回転軸２１と、複数のコイル２２と、モールド樹脂２３とを有する。 As shown in FIG. 3, the rotor 20 has a rotating shaft 21, multiple coils 22, and molded resin 23.
　複数のコイル２２は、巻線コイルである。具体的には、複数のコイル２２は、電線によって構成された電機子巻線である。複数のコイル２２は、電流が流れることで固定子１０に作用する磁力を発生するように巻回されている。コイル２２が発生する主磁束の向きは、回転軸２１が延伸する軸心Ｃに沿った方向である。具体的には、複数のコイル２２は、扁平状に巻回されている。複数のコイルのコイル面は、回転軸２１が延伸する軸心Ｃに沿った方向を向く姿勢で配置されている。 The multiple coils 22 are wound coils. Specifically, the multiple coils 22 are armature windings made of electric wire. The multiple coils 22 are wound so that a magnetic force acting on the stator 10 is generated when a current flows through them. The direction of the main magnetic flux generated by the coils 22 is along the axis C to which the rotating shaft 21 extends. Specifically, the multiple coils 22 are wound in a flat shape. The coil surfaces of the multiple coils are arranged in a position facing in a direction along the axis C to which the rotating shaft 21 extends.
　コイル２２は、銅又はアルミニウム等の金属からなる芯線と、芯線を被膜する絶縁膜とを有する絶縁被覆線によって構成されている。複数のコイル２２は、この絶縁被覆線が平面状に巻回されたコイル層を有する薄形の巻線コイルである。具体的には、複数のコイル２２は、例えば、絶縁被覆線が平面視で実質的に扇状に巻回された１層又は複数のコイル層によって構成されている。このように構成された複数のコイル２２は、回転軸２１が延伸する軸心Ｃ方向から見たときに、回転軸２１を囲むように環状に配置されている。 The coils 22 are composed of an insulated wire having a core wire made of a metal such as copper or aluminum and an insulating film coating the core wire. The multiple coils 22 are thin wound coils having a coil layer in which the insulated wire is wound in a planar shape. Specifically, the multiple coils 22 are composed of, for example, one layer or multiple coil layers in which the insulated wire is wound in a substantially fan-like shape in a planar view. The multiple coils 22 thus configured are arranged in a ring shape surrounding the rotating shaft 21 when viewed from the direction of the axis C along which the rotating shaft 21 extends.
　複数のコイル２２は、整流子３０と電気的に接続されている。具体的には、複数のコイル２２は、整流子３０が有する複数の整流子片３１のいずれかと電気的に接続されている。したがって、複数のコイル２２には、ブラシ４０が接する整流子片３１を介して電流が流れる。 The multiple coils 22 are electrically connected to the commutator 30. Specifically, the multiple coils 22 are electrically connected to one of the multiple commutator segments 31 that the commutator 30 has. Therefore, current flows through the multiple coils 22 via the commutator segment 31 that the brush 40 contacts.
　複数のコイル２２は、モールド樹脂２３で覆われることでモールド樹脂２３とともに一体に成型されている。つまり、複数のコイル２２は、樹脂モールド成型されている。したがって、図４に示すように、複数のコイル２２をモールドした後のモールド樹脂２３の外形の平面視形状は、円形である。モールド樹脂２３として、例えばフェノール樹脂又は不飽和ポリエステル（ＢＭＣ（Ｂｕｌｋ　Ｍｏｌｄｉｎｇ　Ｃｏｍｐｏｕｎｄ））等の絶縁性樹脂材料を用いることができる。モールド樹脂２３は、熱硬化性樹脂及び熱可塑性樹脂のいずれであってもよい。図３に示すように、モールド樹脂２３は、円筒部材２４を介して回転軸２１に固定されている。 The multiple coils 22 are molded integrally with the molded resin 23 by being covered with the molded resin 23. In other words, the multiple coils 22 are resin molded. Therefore, as shown in FIG. 4, the external shape of the molded resin 23 after the multiple coils 22 are molded is circular in a plan view. As the molded resin 23, for example, an insulating resin material such as phenolic resin or unsaturated polyester (BMC (Bulk Molding Compound)) can be used. The molded resin 23 may be either a thermosetting resin or a thermoplastic resin. As shown in FIG. 3, the molded resin 23 is fixed to the rotating shaft 21 via a cylindrical member 24.
　このように、電動機１は、回転子２０がコアを有していないコアレスモータである。電動機１は、回転子２０の複数のコイル２２が薄形で樹脂モールド成型されている。これにより、インダクタンスが低い薄型の電動機１を実現することができる。 In this way, the electric motor 1 is a coreless motor in which the rotor 20 does not have a core. The multiple coils 22 of the rotor 20 of the electric motor 1 are thin and molded from resin. This makes it possible to realize a thin electric motor 1 with low inductance.
　図３に示すように、整流子３０は、回転軸２１に取り付けられている。したがって、整流子３０は、回転子２０が回転することで回転軸２１とともに回転する。回転軸２１に取り付けられた整流子３０は、回転子２０の一部であってもよい。 As shown in FIG. 3, the commutator 30 is attached to the rotating shaft 21. Therefore, the commutator 30 rotates together with the rotating shaft 21 as the rotor 20 rotates. The commutator 30 attached to the rotating shaft 21 may be a part of the rotor 20.
　図５Ａに示すように、整流子３０は、回転軸２１の回転方向に沿って設けられた複数の整流子片３１（整流子セグメント）を有する。具体的には、複数の整流子片３１は、回転軸２１を囲むように、回転軸２１の回転方向に沿って円環状に配列されている。各整流子片３１の形状は、回転軸２１の長手方向に延在する長尺状部材である。各整流子片３１は、表面に段差を有するように形成されている。 As shown in FIG. 5A, the commutator 30 has a plurality of commutator pieces 31 (commutator segments) arranged along the rotational direction of the rotating shaft 21. Specifically, the plurality of commutator pieces 31 are arranged in an annular shape along the rotational direction of the rotating shaft 21 so as to surround the rotating shaft 21. Each commutator piece 31 is shaped as an elongated member extending in the longitudinal direction of the rotating shaft 21. Each commutator piece 31 is formed so as to have a step on its surface.
　複数の整流子片３１は、銅等の金属材料によって構成された導電端子である。複数の整流子片３１は、回転子２０が有するコイル２２と電気的に接続されている。複数の整流子片３１は、互いに絶縁分離されて配置されている。複数の整流子片３１は、それぞれ回転子２０のコイル２２によって電気的に接続されている。 The multiple commutator segments 31 are conductive terminals made of a metal material such as copper. The multiple commutator segments 31 are electrically connected to the coils 22 of the rotor 20. The multiple commutator segments 31 are arranged insulated and separated from each other. The multiple commutator segments 31 are each electrically connected by the coils 22 of the rotor 20.
　整流子３０は、モールド整流子である。整流子３０は、複数の整流子片３１が樹脂によってモールドされた構成になっている。この場合、複数の整流子片３１は、表面が露出するように樹脂に埋め込まれている。複数の整流子片３１は、複数の整流子片３１をモールドする樹脂が回転軸２１に固定されることで、回転軸２１に固定されている。複数の整流子片３１を覆うモールド樹脂とコイル２２を覆うモールド樹脂２３とは、一体である。複数の整流子片３１を覆うモールド樹脂とコイル２２を覆うモールド樹脂２３とは、同じ樹脂材料によって構成されていてもよいし、異なる樹脂材料又は同じ樹脂材料によって構成された別体であってもよい。 The commutator 30 is a molded commutator. The commutator 30 is configured with multiple commutator segments 31 molded with resin. In this case, the multiple commutator segments 31 are embedded in the resin so that their surfaces are exposed. The multiple commutator segments 31 are fixed to the rotating shaft 21 by fixing the resin that molds the multiple commutator segments 31 to the rotating shaft 21. The molded resin that covers the multiple commutator segments 31 and the molded resin 23 that covers the coil 22 are integrated. The molded resin that covers the multiple commutator segments 31 and the molded resin 23 that covers the coil 22 may be made of the same resin material, or may be separate bodies made of different resin materials or the same resin material.
　整流子３０には、少なくとも１つのブラシ４０が接している。具体的には、ブラシ４０の先端部が整流子３０の整流子片３１に接している。ブラシ４０は、回転軸２１の軸心Ｃの方向に直交する方向（径方向）において、整流子片３１に接している。回転軸２１の回転により整流子３０が回転するため、ブラシ４０は、全ての整流子片３１と順次接触し続ける。 At least one brush 40 is in contact with the commutator 30. Specifically, the tip of the brush 40 is in contact with the commutator segments 31 of the commutator 30. The brush 40 is in contact with the commutator segments 31 in a direction (radial direction) perpendicular to the direction of the axis C of the rotating shaft 21. Since the commutator 30 rotates due to the rotation of the rotating shaft 21, the brush 40 continues to come into contact with all the commutator segments 31 in sequence.
　ブラシ４０は、コイル２２に電力を供給するための給電ブラシである。ブラシ４０には、端子７０と電気的に接続された導電線８０が接続されている。ブラシ４０が整流子片３１に接することで、導電線８０を介してブラシ４０に供給される電流（電機子電流）が、整流子片３１を介して回転子２０のコイル２２に流れる。 Brush 40 is a power supply brush for supplying power to coil 22. Brush 40 is connected to conductive wire 80, which is electrically connected to terminal 70. When brush 40 comes into contact with commutator segments 31, the current (armature current) supplied to brush 40 via conductive wire 80 flows through commutator segments 31 to coil 22 of rotor 20.
　ブラシ４０は、カーボンを主成分とする導電性のカーボンブラシである。この場合、ブラシ４０は、銅等の金属を含むカーボンブラシであるとよい。これにより、ブラシ４０と整流子片３１との接触抵抗を小さくすることができる。一例として、ブラシ４０は、焼結体からなる焼結ブラシである。この場合、焼結体であるブラシ４０は、例えば、黒鉛粉と銅紛とバインダー樹脂と硬化剤とを混錬した混錬物を金型に入れて圧縮成型して焼成することで作製することができる。本実施の形態において、ブラシ４０は、切削加工を施すことなく作製している。つまり、ブラシ４０は、黒鉛粉と銅紛との粉末を金型に入れて圧縮成型して焼成した後に、切削加工を施していない。 Brush 40 is a conductive carbon brush whose main component is carbon. In this case, brush 40 is preferably a carbon brush containing a metal such as copper. This can reduce the contact resistance between brush 40 and commutator segments 31. As an example, brush 40 is a sintered brush made of a sintered body. In this case, brush 40, which is a sintered body, can be produced, for example, by putting a mixture of graphite powder, copper powder, binder resin, and hardener into a mold, compression molding, and sintering. In this embodiment, brush 40 is produced without cutting. In other words, brush 40 is produced after graphite powder and copper powder are put into a mold, compression molding, and sintering, and then no cutting is performed.
　図５Ａ及び図５Ｂに示すように、ブラシ４０は、円弧状である。具体的には、ブラシ４０は、断面形状が実質的に矩形状である。ブラシ４０は、上面視形状が円弧をなす形状である。ブラシ４０を上面視したときに、ブラシ４０の幅は、一定である。円弧状であるブラシ４０の上面視形状は、厳密に円弧でなくてもよく、概ね円弧であればよい。 As shown in Figures 5A and 5B, the brush 40 is arc-shaped. Specifically, the cross-sectional shape of the brush 40 is substantially rectangular. The brush 40 has a shape that forms an arc when viewed from above. When viewed from above, the width of the brush 40 is constant. The top view shape of the arc-shaped brush 40 does not have to be strictly an arc, but may be approximately an arc.
　図４及び図５Ａに示すように、ブラシ４０は、一対の互いに反対側の側面として、第１側面４１及び第２側面４２を有する。第１側面４１は、ブラシ４０を構成する円弧の外周側の側面である。第２側面４２は、ブラシ４０を構成する円弧の内周側の側面である。 As shown in Figures 4 and 5A, the brush 40 has a pair of opposite side surfaces, a first side surface 41 and a second side surface 42. The first side surface 41 is the side surface on the outer periphery of the arc that constitutes the brush 40. The second side surface 42 is the side surface on the inner periphery of the arc that constitutes the brush 40.
　ブラシ４０の幅は一定であるので、外周側の第１側面４１の円弧の曲率は、内周側の第２側面４２の円弧の曲率よりも小さい。第１側面４１及び第２側面４２は、円筒面である。したがって、第１側面４１の円弧をなす円の中心点は、１つである。同様に、第２側面４２の円弧をなす円の中心点も、１つである。第１側面４１の円弧をなす円の中心点と、第２側面４２の円弧をなす円の中心点とは、一致している。つまり、第１側面４１の円弧をなす円と第２側面４２の円弧をなす円とは、同心円である。なお、第１側面４１の円弧をなす円の中心点と、第２側面４２の円弧をなす円の中心点とは、一致していなくてもよい。 Since the width of the brush 40 is constant, the curvature of the arc of the first side surface 41 on the outer periphery is smaller than the curvature of the arc of the second side surface 42 on the inner periphery. The first side surface 41 and the second side surface 42 are cylindrical surfaces. Therefore, the circle that forms the arc of the first side surface 41 has one center point. Similarly, the circle that forms the arc of the second side surface 42 also has one center point. The center point of the circle that forms the arc of the first side surface 41 and the center point of the circle that forms the arc of the second side surface 42 are the same. In other words, the circle that forms the arc of the first side surface 41 and the circle that forms the arc of the second side surface 42 are concentric circles. Note that the center point of the circle that forms the arc of the first side surface 41 and the center point of the circle that forms the arc of the second side surface 42 do not have to be the same.
　ブラシ４０は、整流子３０に接する面である前端面４３と、前端面４３とは反対側の面である後端面４４とを有する。前端面４３は、ブラシ４０の長手方向の一方の端部である前端部における端面である。前端面４３は、整流子３０の整流子片３１に摺接する摺接面である。後端面４４は、ブラシ４０の長手方向の他方の端部である後端部における端面である。後端面４４は、ブラシバネ５０の渦巻部５１に接する面である。 The brush 40 has a front end face 43 which is a surface that contacts the commutator 30, and a rear end face 44 which is a surface opposite to the front end face 43. The front end face 43 is an end face at the front end, which is one end in the longitudinal direction of the brush 40. The front end face 43 is a sliding surface that comes into sliding contact with the commutator pieces 31 of the commutator 30. The rear end face 44 is an end face at the rear end, which is the other end in the longitudinal direction of the brush 40. The rear end face 44 is a surface that comes into contact with the spiral portion 51 of the brush spring 50.
　前端面４３及び後端面４４は、実質的に矩形の平坦面である。しかし、これに限らない。例えば、前端面４３は、整流子片３１の表面の形状に沿って湾曲する凹状の湾曲面であってもよい。後端面４４は、ブラシバネ５０の渦巻部５１の一部が収納されるように、渦巻部５１の表面形状に沿って湾曲する凹状の湾曲面であってもよい。 The front end surface 43 and the rear end surface 44 are substantially rectangular flat surfaces. However, this is not limited thereto. For example, the front end surface 43 may be a concave curved surface that curves along the surface shape of the commutator piece 31. The rear end surface 44 may be a concave curved surface that curves along the surface shape of the spiral portion 51 so that a part of the spiral portion 51 of the brush spring 50 is accommodated therein.
　ブラシ４０の前端面４３は、前端面４３の中心線が整流子３０の表面に対して垂直となるように整流子３０に接している。つまり、ブラシ４０の前端面４３と整流子３０とが接触する箇所において、ブラシ４０の接線と電動機１の回転方向とのなす角度は、９０°になっている（図５Ｂの拡大部分を参照）。 The front end surface 43 of the brush 40 contacts the commutator 30 so that the center line of the front end surface 43 is perpendicular to the surface of the commutator 30. In other words, at the point where the front end surface 43 of the brush 40 contacts the commutator 30, the angle between the tangent line of the brush 40 and the direction of rotation of the motor 1 is 90° (see the enlarged portion of Figure 5B).
　ブラシ４０は、複数配置されている。この場合、ブラシ４０は、回転子２０の回転方向に沿って等間隔に複数配置されているとよい。具体的には、ブラシ４０は、２つ配置されている。２つのブラシ４０は、整流子３０を挟むように対向して配置されている。つまり、２つのブラシ４０は、回転子２０の回転方向に沿って１８０°間隔で配置されている。具体的には、一方のブラシ４０の前端面４３と他方のブラシ４０の前端面４３とは、回転軸２１を挟んで対向している。 Multiple brushes 40 are arranged. In this case, it is preferable that the multiple brushes 40 are arranged at equal intervals along the rotation direction of the rotor 20. Specifically, two brushes 40 are arranged. The two brushes 40 are arranged opposite each other with the commutator 30 in between. In other words, the two brushes 40 are arranged at 180° intervals along the rotation direction of the rotor 20. Specifically, the front end face 43 of one brush 40 and the front end face 43 of the other brush 40 face each other with the rotation shaft 21 in between.
　２つのブラシ４０の各々は、いずれも長尺状である。図５Ｂに示すように、ブラシ４０の円弧をなす円の中心を中心点とすると、この中心点とブラシ４０の前端面４３とを結ぶ線と、中心点とブラシ４０の後端面４４とを結ぶ線とのなす角θは、９０°以上（θ≧９０°）になっている。つまり、２つのブラシ４０は、いずれもブラシ４０の円弧の中心角が９０°以上になっている。具体的には、２つのブラシ４０において、第１側面４１及び第２側面４２は、いずれも円弧の中心角が９０°以上になっている。２つのブラシ４０は、同じ形状である。しかし、これに限らない。 Each of the two brushes 40 is elongated. As shown in FIG. 5B , if the center of the circle forming the arc of the brush 40 is taken as the center point, the angle θ between the line connecting this center point to the front end surface 43 of the brush 40 and the line connecting the center point to the rear end surface 44 of the brush 40 is 90° or more (θ≧90°). In other words, the central angle of the arc of the brush 40 of both brushes 40 is 90° or more. Specifically, in both brushes 40, the first side surface 41 and the second side surface 42 both have central angles of the arc of 90° or more. The two brushes 40 have the same shape. However, this is not limited to this.
　ブラシ４０は、ブラシバネ５０からの押圧力を受けて、整流子３０の整流子片３１と常に接している。具体的には、図５Ｂに示すように、ブラシ４０がブラシバネ５０によって整流子３０に押し付けられることで、ブラシ４０の前端面４３が整流子片３１に接している。ブラシ４０は、回転する整流子片３１に接触し続けることで摩耗する。このように、ブラシ４０は、ブラシバネ５０からの押圧力を受けて整流子３０に摺接する。同時に、ブラシ４０は、整流子３０との摩耗により短くなっていく。 The brush 40 is constantly in contact with the commutator segments 31 of the commutator 30 due to the pressing force of the brush spring 50. Specifically, as shown in FIG. 5B, the brush 40 is pressed against the commutator 30 by the brush spring 50, so that the front end surface 43 of the brush 40 is in contact with the commutator segments 31. The brush 40 wears out due to its continuous contact with the rotating commutator segments 31. In this way, the brush 40 is in sliding contact with the commutator 30 due to the pressing force of the brush spring 50. At the same time, the brush 40 becomes shorter due to wear caused by the commutator 30.
　ブラシバネ５０は、ブラシ４０の数に応じて設けられている。電動機１には、２つのブラシ４０が設けられているので、ブラシバネ５０も２つ設けられている。ブラシ４０及びブラシバネ５０は、ブラシホルダ６０に保持されている。 The brush springs 50 are provided according to the number of brushes 40. Since the electric motor 1 is provided with two brushes 40, two brush springs 50 are also provided. The brushes 40 and brush springs 50 are held in the brush holder 60.
　ブラシバネ５０は、バネ弾性力によってブラシ４０に押圧（バネ圧）を付与している。ブラシバネ５０は、ブラシ４０を整流子３０に向けて付勢している。ブラシバネ５０は、定荷重バネである。したがって、ブラシバネ５０は、ブラシ４０に均一な荷重を付与している。つまり、ブラシバネ５０は、ブラシ４０が摩耗する前の初期時から、ブラシ４０が摩耗して電動機１が寿命に到達したときの末期時にわたって、ブラシ４０に均一な押圧力を付与する。 The brush spring 50 applies a pressure (spring pressure) to the brush 40 by the spring elastic force. The brush spring 50 biases the brush 40 toward the commutator 30. The brush spring 50 is a constant load spring. Therefore, the brush spring 50 applies a uniform load to the brush 40. In other words, the brush spring 50 applies a uniform pressure to the brush 40 from the initial stage before the brush 40 wears out to the final stage when the brush 40 wears out and the motor 1 reaches the end of its life.
　定荷重バネであるブラシバネ５０は、帯状の線材により構成されている。図４～図６に示すように、ブラシバネ５０は、渦巻バネである。ブラシバネ５０は、帯状の線材が渦巻状に巻回された渦巻部５１（コイル部）を有する。ブラシバネ５０は、例えば、鋼板等の金属材料等からなる１枚の帯板状の線材によって構成されている。 The brush spring 50, which is a constant-load spring, is made of a strip-shaped wire material. As shown in Figures 4 to 6, the brush spring 50 is a spiral spring. The brush spring 50 has a spiral portion 51 (coil portion) in which a strip-shaped wire material is wound in a spiral shape. The brush spring 50 is made of a single strip-shaped wire material made of a metal material such as a steel plate.
　具体的には、ブラシバネ５０を構成する線材は、長尺状かつ帯状の金属板である。したがって、渦巻部５１は、定荷重バネにおいて、長尺状かつ帯状の金属板が一方向のみに渦巻状に複数回巻かれた部分である。ブラシバネ５０は、渦巻状の渦巻部５１から線材の一方の端部を引き延ばすことで、元の渦巻状の状態に戻る力（バネ復元力）が発生する。一例として、ブラシバネ５０は、ステンレス製の金属板によって構成されている。 Specifically, the wire that constitutes brush spring 50 is a long, band-shaped metal plate. Thus, spiral portion 51 is the portion of the constant-load spring in which the long, band-shaped metal plate is wound in a spiral shape multiple times in only one direction. Brush spring 50 generates a force (spring restoring force) that returns the wire to its original spiral state by stretching one end of the wire from spiral portion 51. As an example, brush spring 50 is made of a stainless steel metal plate.
　図５Ａに示すように、ブラシバネ５０は、帯状の金属板の一方の端部である外側端部５０ａと、帯状の金属板の他方の端部である内側端部５０ｂとを有する。外側端部５０ａは、渦巻部５１の最外周から外側に引き出された帯状の金属板の一方の先端部である。内側端部５０ｂは、渦巻部５１の最内周に位置する帯状の金属板の他方の先端部である。 As shown in FIG. 5A, the brush spring 50 has an outer end 50a which is one end of a strip of metal plate, and an inner end 50b which is the other end of the strip of metal plate. The outer end 50a is one end of the strip of metal plate that is pulled outward from the outermost periphery of the spiral portion 51. The inner end 50b is the other end of the strip of metal plate that is located at the innermost periphery of the spiral portion 51.
　図５Ａ及び図６に示すように、ブラシバネ５０は、渦巻部５１によってブラシ４０を整流子３０に押し付けている。具体的には、ブラシバネ５０は、渦巻部５１がブラシ４０の後端面４４に接している。ブラシバネ５０は、渦巻部５１のバネ復元力によってブラシ４０に押圧荷重を付与している。つまり、ブラシバネ５０は、渦巻部５１によってブラシ４０に押圧力（バネ圧）を付与している。これにより、ブラシ４０は、整流子３０に向けて付勢される。 As shown in Figures 5A and 6, the brush spring 50 presses the brush 40 against the commutator 30 with the spiral portion 51. Specifically, the spiral portion 51 of the brush spring 50 contacts the rear end surface 44 of the brush 40. The brush spring 50 applies a pressing load to the brush 40 with the spring restoring force of the spiral portion 51. In other words, the brush spring 50 applies a pressing force (spring pressure) to the brush 40 with the spiral portion 51. This biases the brush 40 towards the commutator 30.
　図７は、図６において、一対のブラシ４０と一対のブラシバネ５０と整流子３０との位置関係を示す斜視図である。図８は、図７において、１つのブラシ４０と１つのブラシバネ５０と整流子３０との位置関係を示す上面図である。図７及び図８に示すように、ブラシバネ５０は、ブラシ４０の外周側の側面である第１側面４１に接触するように配置されている。 FIG. 7 is a perspective view showing the positional relationship between a pair of brushes 40, a pair of brush springs 50, and the commutator 30 in FIG. 6. FIG. 8 is a top view showing the positional relationship between one brush 40, one brush spring 50, and the commutator 30 in FIG. 7. As shown in FIGS. 7 and 8, the brush spring 50 is positioned so as to contact the first side surface 41, which is the side surface on the outer periphery of the brush 40.
　具体的には、ブラシバネ５０の渦巻部５１から引き出された帯状の線材（金属板）が、ブラシ４０の第１側面４１に沿って延在している。したがって、ブラシバネ５０の渦巻部５１から引き出された帯状の線材は、ブラシ４０と同様に、円弧状に湾曲している。なお、ブラシバネ５０を構成する線材の幅は、ブラシ４０の第１側面４１の幅の１／３以上２／３以下にするとよい。これにより、ブラシバネ５０とブラシ４０との滑り性を良化しつつ、ブラシバネ５０よって安定した押圧荷重をブラシ４０に与えることができる。 Specifically, a strip of wire (metal plate) pulled out from the spiral portion 51 of the brush spring 50 extends along the first side surface 41 of the brush 40. Therefore, the strip of wire pulled out from the spiral portion 51 of the brush spring 50 is curved in an arc, just like the brush 40. The width of the wire constituting the brush spring 50 should be between 1/3 and 2/3 of the width of the first side surface 41 of the brush 40. This improves the sliding properties between the brush spring 50 and the brush 40, while allowing the brush spring 50 to apply a stable pressure load to the brush 40.
　図５Ａ及び図６に示すように、ブラシ４０は、ブラシホルダ６０に保持されている。図２及び図３に示すように、ブラシホルダ６０は、電動機１の外殻を構成する外殻部材でもある。ブラシホルダ６０は、第２ブラケット１０２を外側から覆っている。 As shown in Figures 5A and 6, the brush 40 is held by the brush holder 60. As shown in Figures 2 and 3, the brush holder 60 is also an outer shell member that constitutes the outer shell of the electric motor 1. The brush holder 60 covers the second bracket 102 from the outside.
　ブラシホルダ６０は、例えば、絶縁性の樹脂材料によって構成されている。ブラシホルダ６０は、樹脂材料を用いた一体成型により形成された樹脂成型品である。一例として、ブラシホルダ６０を構成する樹脂材料は、フェノール樹脂である。しかし、これに限らない。 The brush holder 60 is made of, for example, an insulating resin material. The brush holder 60 is a resin molded product formed by integral molding using a resin material. As an example, the resin material that makes up the brush holder 60 is phenolic resin. However, this is not limited to this.
　図３～図６に示すように、ブラシホルダ６０は、ブラシ４０が収納される空間領域であるブラシ収納部６０ａを有する。図３に示すように、ブラシ収納部６０ａは、凹状に形成された凹部である。図５Ａ及び図６に示すように、ブラシ収納部６０ａは、ブラシ４０の形状に沿って長尺状に形成されている。つまり、ブラシ収納部６０ａは、円弧状に湾曲している。図９は、実施の形態１に係る電動機１におけるブラシホルダ６０の斜視図である。図９に示すように、ブラシ収納部６０ａの長手方向の両端部は、いずれも開口している。つまり、ブラシ収納部６０ａは、ブラシ４０の前端面４３側の前方端部が開口しているだけではなく、ブラシ４０の後端面４４側の後方端部も開口している。 As shown in Figures 3 to 6, the brush holder 60 has a brush storage section 60a, which is a spatial area in which the brush 40 is stored. As shown in Figure 3, the brush storage section 60a is a recessed portion formed in a concave shape. As shown in Figures 5A and 6, the brush storage section 60a is formed in an elongated shape that conforms to the shape of the brush 40. In other words, the brush storage section 60a is curved in an arc shape. Figure 9 is a perspective view of the brush holder 60 in the electric motor 1 according to the first embodiment. As shown in Figure 9, both ends of the brush storage section 60a in the longitudinal direction are both open. In other words, the brush storage section 60a is not only open at the front end on the front end surface 43 side of the brush 40, but also at the rear end on the rear end surface 44 side of the brush 40.
　図５Ａ及び図６に示すように、ブラシ収納部６０ａには、ブラシ４０とともにブラシバネ５０も収納されている。したがって、ブラシ収納部６０ａの長手方向の長さは、ブラシ４０の長さよりも長くなっている。具体的には、ブラシバネ５０は、渦巻部５１がブラシ４０の後端部の後方側に位置するようにブラシ収納部６０ａに配置される。この場合、ブラシバネ５０を構成する帯状の線材（金属板）は、ブラシ収納部６０ａの円弧形状に沿って、渦巻部５１から整流子３０側に向けて引き出される。具体的には、図６～図８に示すように、ブラシバネ５０を構成する帯状の線材は、渦巻部５１からブラシ４０の第１側面４１に沿って引き出される。 As shown in Figures 5A and 6, the brush storage section 60a stores the brush spring 50 together with the brush 40. Therefore, the longitudinal length of the brush storage section 60a is longer than the length of the brush 40. Specifically, the brush spring 50 is arranged in the brush storage section 60a so that the spiral portion 51 is located rearward of the rear end of the brush 40. In this case, the strip-shaped wire material (metal plate) constituting the brush spring 50 is pulled out from the spiral portion 51 toward the commutator 30 along the arc shape of the brush storage section 60a. Specifically, as shown in Figures 6 to 8, the strip-shaped wire material constituting the brush spring 50 is pulled out from the spiral portion 51 along the first side surface 41 of the brush 40.
　ブラシバネ５０の渦巻部５１から引き出された帯状の線材の外側端部５０ａは、ブラシホルダ６０におけるブラシ収納部６０ａの前方端部の開口近傍に形成された固定部６０ｂに固定される。ブラシバネ５０の外側端部５０ａが固定される固定部６０ｂは、切り欠き溝である。この場合、図５Ａに示すように、ブラシバネ５０の外側端部５０ａに形成されたＶ字状の折曲部を固定部６０ｂに係止させることで、ブラシバネ５０の外側端部５０ａが固定部６０ｂに固定される。 The outer end 50a of the strip-shaped wire pulled out from the spiral portion 51 of the brush spring 50 is fixed to a fixing portion 60b formed near the opening at the front end of the brush storage portion 60a in the brush holder 60. The fixing portion 60b to which the outer end 50a of the brush spring 50 is fixed is a notched groove. In this case, as shown in FIG. 5A, the outer end 50a of the brush spring 50 is fixed to the fixing portion 60b by engaging the V-shaped bent portion formed at the outer end 50a of the brush spring 50 with the fixing portion 60b.
　図３に示すように、ブラシ収納部６０ａに収納されたブラシ４０は、カバープレート１１０によって覆われている。ブラシ収納部６０ａには、ブラシ４０だけではなくブラシバネ５０も収納されている。したがって、カバープレート１１０は、ブラシ４０を覆っているだけではなく、ブラシバネ５０も覆っている。カバープレート１１０は、例えば、金属板によって構成された金属カバーである。カバープレート１１０は、ブラシ収納部６０ａに蓋をするように配置される。図４に示すように、カバープレート１１０には係止爪が設けられている。この係止爪をブラシホルダ６０に形成された係止穴に挿入することで、カバープレート１１０をブラシホルダ６０に固定することができる。 As shown in FIG. 3, the brush 40 stored in the brush storage section 60a is covered by a cover plate 110. In addition to the brush 40, the brush spring 50 is also stored in the brush storage section 60a. Therefore, the cover plate 110 not only covers the brush 40, but also the brush spring 50. The cover plate 110 is, for example, a metal cover made of a metal plate. The cover plate 110 is arranged so as to cover the brush storage section 60a. As shown in FIG. 4, the cover plate 110 is provided with a locking claw. By inserting this locking claw into a locking hole formed in the brush holder 60, the cover plate 110 can be fixed to the brush holder 60.
　ブラシ収納部６０ａは、ブラシ４０の数に応じて形成されている。ブラシ４０の数は２つであるので、ブラシホルダ６０には、２つのブラシ収納部６０ａが形成されている。２つのブラシ収納部６０ａは、ブラシ４０が延在する方向に長尺である。かつ、２つのブラシ収納部６０ａは、断面形状が矩形の凹状に形成されている。 The brush storage sections 60a are formed according to the number of brushes 40. Since there are two brushes 40, two brush storage sections 60a are formed in the brush holder 60. The two brush storage sections 60a are long in the direction in which the brushes 40 extend. Furthermore, the two brush storage sections 60a are formed with a rectangular concave cross-sectional shape.
　図４に示すように、ブラシ収納部６０ａは、第１側壁６１と、第２側壁６２と、底壁６３とを有する。第１側壁６１は、ブラシ４０の第１側面４１に対向する。第２側壁６２は、ブラシ４０の第２側面４２に対向する。底壁６３は、ブラシ４０の底面を支持する。 As shown in FIG. 4, the brush storage section 60a has a first side wall 61, a second side wall 62, and a bottom wall 63. The first side wall 61 faces the first side surface 41 of the brush 40. The second side wall 62 faces the second side surface 42 of the brush 40. The bottom wall 63 supports the bottom surface of the brush 40.
　図５Ａ及び図６に示すように、第１側壁６１及び第２側壁６２は、ブラシ４０を挟む一対の側壁である。第１側壁６１及び第２側壁６２は、円弧状のブラシ４０と同様に、円弧状に形成されている。ブラシバネ５０の外側端部５０ａが固定される固定部６０ｂ（係止穴）は、第１側壁６１の整流子３０側の端部に形成されている。 As shown in Figures 5A and 6, the first side wall 61 and the second side wall 62 are a pair of side walls that sandwich the brush 40. The first side wall 61 and the second side wall 62 are formed in an arc shape, similar to the arc shape of the brush 40. A fixing portion 60b (locking hole) to which the outer end portion 50a of the brush spring 50 is fixed is formed at the end portion of the first side wall 61 on the commutator 30 side.
　第１側壁６１は、ブラシ４０の外周側の側面である第１側面４１に対面する円弧状の側壁面を有する。第２側壁６２は、ブラシ４０の内周側の側面である第２側面４２に対面する円弧状の側壁面を有する。 The first side wall 61 has an arc-shaped side wall surface that faces the first side surface 41, which is the side surface on the outer periphery of the brush 40. The second side wall 62 has an arc-shaped side wall surface that faces the second side surface 42, which is the side surface on the inner periphery of the brush 40.
　ブラシ収納部６０ａは、ブラシ４０がブラシ収納部６０ａに沿って１回転できる形状を有する。つまり、円弧状のブラシ４０をブラシ収納部６０ａに沿って一回転させたとしても、ブラシホルダ６０には、ブラシ４０が接触する障害物が存在しない。ブラシ４０が円弧状であるので、ブラシ収納部６０ａは、ブラシ４０の円弧を構成する円の少なくとも一部をなすように形成されている。具体的には、第１側壁６１及び第２側壁６２の上面視形状は、ブラシ４０の円弧を構成する円の円弧になっている。 The brush storage section 60a has a shape that allows the brush 40 to rotate once along the brush storage section 60a. In other words, even if the arc-shaped brush 40 is rotated once along the brush storage section 60a, there is no obstacle in the brush holder 60 that the brush 40 comes into contact with. Since the brush 40 is arc-shaped, the brush storage section 60a is formed to form at least a part of the circle that constitutes the arc of the brush 40. Specifically, the shape of the first side wall 61 and the second side wall 62 when viewed from above is an arc of the circle that constitutes the arc of the brush 40.
　第１側壁６１と第２側壁６２との間隔は一定である。よって、外周側の第１側壁６１の円弧の曲率は、内周側の第２側壁６２の円弧の曲率よりも小さい。第１側壁６１の側壁面及び第２側壁６２の側壁面は、円筒面である。したがって、第１側壁６１の円弧をなす円の中心点は、１つである。同様に、第２側壁６２の円弧をなす円の中心点も、１つである。第１側壁６１の側壁面の円弧をなす円の中心点と、第２側壁６２の側壁面の円弧をなす円の中心点とは、一致している。つまり、第１側壁６１の円弧をなす円と第２側壁６２の円弧をなす円とは、同心円である。 The distance between the first side wall 61 and the second side wall 62 is constant. Therefore, the curvature of the arc of the first side wall 61 on the outer periphery side is smaller than the curvature of the arc of the second side wall 62 on the inner periphery side. The side wall surfaces of the first side wall 61 and the second side wall 62 are cylindrical surfaces. Therefore, the circle forming the arc of the first side wall 61 has one center point. Similarly, the circle forming the arc of the second side wall 62 also has one center point. The center point of the circle forming the arc of the side wall surface of the first side wall 61 and the center point of the circle forming the arc of the side wall surface of the second side wall 62 are concentric.
　ブラシ収納部６０ａは、ブラシ４０がブラシ収納部６０ａに沿って１回転できるように形成されている。したがって、第１側壁６１の側壁面の円弧をなす円と、第２側壁６２の側壁面の円弧をなす円と、ブラシ４０の第１側面４１の円弧をなす円と、ブラシ４０の第２側面４２の円弧をなす円とは、同心円になっている。 The brush storage section 60a is formed so that the brush 40 can rotate once along the brush storage section 60a. Therefore, the arc circle of the side wall surface of the first side wall 61, the arc circle of the side wall surface of the second side wall 62, the arc circle of the first side surface 41 of the brush 40, and the arc circle of the second side surface 42 of the brush 40 are concentric circles.
　第１側壁６１とブラシ４０の第１側面４１との間には、隙間（クリアランス）が存在する。ブラシ４０の第１側面４１には、ブラシバネ５０の渦巻部５１から引き出された帯状の線材が、接している。ブラシバネ５０の線材と第１側壁６１との間に、隙間が存在している。第２側壁６２とブラシ４０の第２側面４２との間に、隙間が存在していてもよい。第１側壁６１とブラシ４０の第１側面４１との間の隙間、及び第２側壁６２とブラシ４０の第２側面４２との間の隙間は、一例として、１００μｍ以上である。 A gap (clearance) exists between the first side wall 61 and the first side surface 41 of the brush 40. A strip-shaped wire material drawn out from the spiral portion 51 of the brush spring 50 is in contact with the first side surface 41 of the brush 40. A gap exists between the wire material of the brush spring 50 and the first side wall 61. A gap may exist between the second side wall 62 and the second side surface 42 of the brush 40. The gap between the first side wall 61 and the first side surface 41 of the brush 40, and the gap between the second side wall 62 and the second side surface 42 of the brush 40 are, for example, 100 μm or more.
　図５Ａ、図６及び図９に示すように、ブラシホルダ６０は、第３側壁６４を有する。第３側壁６４は、整流子３０に沿って設けられた壁である。第３側壁６４の上面視形状は、円弧状である。第３側壁６４は、整流子３０におけるブラシ４０の第２側面４２（内周側の側面）に対向する部分に設けられている。整流子３０におけるブラシ４０の第２側面４２に対向しない部分には、第３側壁６４は設けられていない。つまり、第３側壁６４は、ブラシ４０の内周側に設けられているが、ブラシ４０の外周側に設けられていない。 As shown in Figures 5A, 6 and 9, the brush holder 60 has a third side wall 64. The third side wall 64 is a wall provided along the commutator 30. The third side wall 64 has an arc shape when viewed from above. The third side wall 64 is provided in a portion of the commutator 30 facing the second side surface 42 (the side surface on the inner circumference side) of the brush 40. The third side wall 64 is not provided in a portion of the commutator 30 that does not face the second side surface 42 of the brush 40. In other words, the third side wall 64 is provided on the inner circumference side of the brush 40, but not on the outer circumference side of the brush 40.
　ブラシホルダ６０には、端子７０が取り付けられている。図４に示すように、端子７０は、一対の脚部を有するように、断面形状が実質的にコの字状となるように形成されている。図９に示すように、ブラシホルダ６０には、スリット状の一対の貫通孔６５が設けられている。端子７０は、端子７０の一対の脚部をブラシホルダ６０に設けられた一対の貫通孔６５に圧入することで、ブラシホルダ６０に固定されている。端子７０は、金属材料の導電材料によって構成された導電端子である。端子７０は、金属板によって構成された金属端子である。 A terminal 70 is attached to the brush holder 60. As shown in FIG. 4, the terminal 70 is formed so that it has a pair of legs and a cross-sectional shape that is substantially U-shaped. As shown in FIG. 9, the brush holder 60 is provided with a pair of slit-shaped through holes 65. The terminal 70 is fixed to the brush holder 60 by pressing the pair of legs of the terminal 70 into the pair of through holes 65 provided in the brush holder 60. The terminal 70 is a conductive terminal made of a conductive metallic material. The terminal 70 is a metal terminal made of a metal plate.
　端子７０は、ブラシ４０を介して回転子２０のコイル２２に通電される電力を受ける。端子７０は、電源端子である。端子７０は、電動機１の外部に配置された外部電源と電気的に接続されることで、外部電源から電源電力を受電する。したがって、端子７０には、外部電源から電力が供給される。外部電源は、電動機１の外部に存在する電源である。外部電源は、電動機１に所定の入力電圧を供給する。 The terminal 70 receives the power passed through the coil 22 of the rotor 20 via the brush 40. The terminal 70 is a power supply terminal. The terminal 70 is electrically connected to an external power supply arranged outside the electric motor 1, and receives power supply power from the external power supply. Therefore, power is supplied to the terminal 70 from the external power supply. The external power supply is a power supply that exists outside the electric motor 1. The external power supply supplies a predetermined input voltage to the electric motor 1.
　外部電源は、電動機１にＤＣ１２Ｖの入力電圧を供給する直流電源である。したがって、端子７０は、入力電圧として直流電圧を受電する。このため、図５Ａ～図７に示すように、電動機１には、一対の電源端子として２つの端子７０が設けられている。この場合、２つの端子７０の一方は、直流電源の正極側に接続される正極側端子（プラス端子）である。２つの端子７０の他方は、直流電源の負極側に接続される負極側端子（マイナス端子）である。 The external power supply is a DC power supply that supplies an input voltage of DC 12V to the electric motor 1. Therefore, the terminal 70 receives the DC voltage as the input voltage. For this reason, as shown in Figures 5A to 7, the electric motor 1 is provided with two terminals 70 as a pair of power supply terminals. In this case, one of the two terminals 70 is a positive terminal (plus terminal) that is connected to the positive side of the DC power supply. The other of the two terminals 70 is a negative terminal (minus terminal) that is connected to the negative side of the DC power supply.
　端子７０は、円弧状のブラシ４０の内側に位置している。つまり、端子７０は、ブラシ４０の第２側面４２と整流子３０との間に位置している。具体的には、端子７０は、ブラシ４０の第２側面４２と第３側壁６４とで囲まれるスペースに配置される。 The terminal 70 is located inside the arc-shaped brush 40. In other words, the terminal 70 is located between the second side surface 42 of the brush 40 and the commutator 30. Specifically, the terminal 70 is disposed in the space surrounded by the second side surface 42 of the brush 40 and the third side wall 64.
　端子７０は、ブラシ４０で囲まれる領域の中央部に配置されている。具体的には、上面視において、端子７０の少なくとも一部は、上面視形状が円弧であるブラシ４０の円弧を構成する円の中心に重なっている。 The terminal 70 is disposed in the center of the area surrounded by the brush 40. Specifically, when viewed from above, at least a portion of the terminal 70 overlaps with the center of the circle that constitutes the arc of the brush 40, which has an arc-shaped shape when viewed from above.
　一対の端子７０と一対のブラシ４０とは、一対一に対応している。つまり、一対の端子７０の一方は、一対のブラシ４０の一方の内側に位置しており、一対の端子７０の他方は、一対のブラシ４０の他方の内側に位置している。 The pair of terminals 70 and the pair of brushes 40 are in one-to-one correspondence. In other words, one of the pair of terminals 70 is located inside one of the pair of brushes 40, and the other of the pair of terminals 70 is located inside the other of the pair of brushes 40.
　図示しないが、ブラシホルダ６０には、コンデンサ及びチョークコイル等の電子部品が配置されていてもよい。このような電子部品は、ブラシ４０及び端子７０と電気的に接続される。 Although not shown, electronic components such as a capacitor and a choke coil may be arranged in the brush holder 60. Such electronic components are electrically connected to the brush 40 and the terminal 70.
　例えば、２つの端子７０と並列接続になるように、１つ又は複数のコンデンサが接続されていてもよい。これにより、コンデンサによって電動機１から発生するノイズを抑制することができる。この場合、コンデンサの一方のリードが２つの端子７０の一方に電気的に接続され、コンデンサの他方のリードが２つの端子７０の他方に電気的に接続される。 For example, one or more capacitors may be connected in parallel to the two terminals 70. This allows the capacitors to suppress noise generated by the motor 1. In this case, one lead of the capacitor is electrically connected to one of the two terminals 70, and the other lead of the capacitor is electrically connected to the other of the two terminals 70.
　ブラシ４０と端子７０との間の電流経路にチョークコイルが挿入されていてもよい。これにより、ブラシ４０と端子７０との間の電流経路に流れる電流に含まれるノイズをチョークコイルによって除去することができる。チョークコイルは、例えば、端子７０と導電線８０との間に挿入される。この場合、チョークコイルの一方の端部は、端子７０に電気的に接続され、チョークコイルの他方の端部は、導電線８０に電気的に接続される。 A choke coil may be inserted in the current path between the brush 40 and the terminal 70. This allows the choke coil to remove noise contained in the current flowing in the current path between the brush 40 and the terminal 70. The choke coil is inserted, for example, between the terminal 70 and the conductive wire 80. In this case, one end of the choke coil is electrically connected to the terminal 70, and the other end of the choke coil is electrically connected to the conductive wire 80.
　ブラシ４０及び端子７０と電気的に接続された電子部品は、ブラシホルダ６０において、端子７０と同様に、円弧状のブラシ４０の内側に配置されているとよい。具体的には、電子部品は、ブラシ４０の第２側面４２と第３側壁６４とで囲まれるスペースに配置される。電子部品は、ブラシ４０の内側に配置されていなくてもよい。例えば、電子部品は、２つのブラシ４０の間のスペースに配置されていてもよい。ブラシホルダ６０に配置される電子部品は、チョークコイル又はコンデンサ等のノイズ除去素子に限るものではない。 The electronic components electrically connected to the brush 40 and the terminal 70 may be arranged inside the arc-shaped brush 40 in the brush holder 60, similar to the terminal 70. Specifically, the electronic components are arranged in the space surrounded by the second side surface 42 and the third side wall 64 of the brush 40. The electronic components do not have to be arranged inside the brush 40. For example, the electronic components may be arranged in the space between two brushes 40. The electronic components arranged in the brush holder 60 are not limited to noise removal elements such as choke coils or capacitors.
　図５Ａ～図８に示すように、ブラシ４０と端子７０とは、導電線８０によって電気的に接続されている。導電線８０には、端子７０から供給される電流が流れる。つまり、導電線８０は、ブラシ４０に給電するための給電線である。導電線８０としては、例えばピグテール線を用いることができる。 As shown in Figs. 5A to 8, the brush 40 and the terminal 70 are electrically connected by a conductive wire 80. A current supplied from the terminal 70 flows through the conductive wire 80. In other words, the conductive wire 80 is a power supply line for supplying power to the brush 40. For example, a pigtail wire can be used as the conductive wire 80.
　図７及び図８に示すように、導電線８０の一方の端部である第１端部８０ａは、ブラシ４０に接続されている。具体的には、導電線８０の第１端部８０ａは、ブラシ４０の後端部に固定されている。ブラシ４０の後端部の上面に、一段下がった段差面を有する段差部が形成されている。導電線８０の第１端部８０ａは、この段差部の段差面に固定されている。この場合、導電線８０の第１端部８０ａは、ブラシ４０に埋め込まれることでブラシ４０に固定されている。 As shown in Figures 7 and 8, the first end 80a, which is one end of the conductive wire 80, is connected to the brush 40. Specifically, the first end 80a of the conductive wire 80 is fixed to the rear end of the brush 40. A step portion having a step surface that is one step lower is formed on the upper surface of the rear end of the brush 40. The first end 80a of the conductive wire 80 is fixed to the step surface of this step portion. In this case, the first end 80a of the conductive wire 80 is fixed to the brush 40 by being embedded in the brush 40.
　導電線８０の他方の端部である第２端部８０ｂは、端子７０と電気的に接続されている。図７及び図８に示すように、導電線８０の第２端部８０ｂは、端子７０に直接接続されている。この場合、導電線８０の第２端部８０ｂと端子７０とは、溶接又は半田等によって接合される。 The other end of the conductive wire 80, the second end 80b, is electrically connected to the terminal 70. As shown in Figures 7 and 8, the second end 80b of the conductive wire 80 is directly connected to the terminal 70. In this case, the second end 80b of the conductive wire 80 and the terminal 70 are joined by welding, soldering, or the like.
　導電線８０は、ブラシ４０が摩耗する前に予めねじられている。導電線８０は、ブラシ４０が摩耗していくにしたがってねじれが緩和するように構成されている。したがって、導電線８０を端子７０に接合する際、導電線８０を複数回ねじって導電線８０の第２端部８０ｂを端子７０に接合する。具体的には、導電線８０は、ブラシ４０が摩耗して最短の長さになったときにねじりがなくなるように構成されている。 The conductive wire 80 is pre-twisted before the brush 40 wears. The conductive wire 80 is configured so that the twist is relaxed as the brush 40 wears. Therefore, when joining the conductive wire 80 to the terminal 70, the conductive wire 80 is twisted multiple times and the second end 80b of the conductive wire 80 is joined to the terminal 70. Specifically, the conductive wire 80 is configured so that the twist is eliminated when the brush 40 wears down to its shortest length.
　ここで、ブラシ４０及びブラシバネ５０をブラシホルダ６０に固定する方法について、図１０～図１２を用いて説明する。図１０は、帯状の線材が渦巻部５１に収納された状態（線材を引き出す前の状態）のブラシバネ５０の斜視図である。図１１は、図１０の状態のブラシバネ５０とブラシ４０とをブラシホルダ６０にセットしたときの様子を示す図である。図１２は、ブラシ４０及びブラシバネ５０をブラシホルダ６０に固定するときの様子を説明するための図である。図１２では、ブラシバネ５０は省略されている。 Here, a method for fixing the brush 40 and brush spring 50 to the brush holder 60 will be described with reference to Figures 10 to 12. Figure 10 is a perspective view of the brush spring 50 in a state where the strip-shaped wire is stored in the spiral portion 51 (before the wire is pulled out). Figure 11 is a diagram showing the brush spring 50 in the state shown in Figure 10 and the brush 40 when set in the brush holder 60. Figure 12 is a diagram for explaining the state when the brush 40 and brush spring 50 are fixed to the brush holder 60. The brush spring 50 is omitted in Figure 12.
　図１１に示すように、まず、図１０の状態のブラシバネ５０とブラシ４０とをブラシホルダ６０にセットする。具体的には、ブラシバネ５０を構成する線材をブラシホルダ６０の固定部６０ｂ（切り欠き溝）に挿入し、ブラシバネ５０の外側端部５０ａに形成されたＶ字状の折曲部の先端をブラシ収納部６０ａの第１側壁６１の外面に係止させて、ブラシバネ５０をブラシ収納部６０ａにセットする。 As shown in Figure 11, first, the brush spring 50 and the brush 40 in the state shown in Figure 10 are set in the brush holder 60. Specifically, the wire that constitutes the brush spring 50 is inserted into the fixing portion 60b (notched groove) of the brush holder 60, and the tip of the V-shaped bent portion formed on the outer end portion 50a of the brush spring 50 is engaged with the outer surface of the first side wall 61 of the brush storage portion 60a, and the brush spring 50 is set in the brush storage portion 60a.
　導電線８０が接続されたブラシ４０を準備し、ブラシ４０の後端面４４をブラシバネ５０の渦巻部５１に当接させた状態で、ブラシ４０をブラシ収納部６０ａにセットする。このとき、ブラシ４０の一部は、ブラシ収納部６０ａからはみ出している。具体的には、ブラシ４０の一部は、整流子３０が配置される領域（第３側壁６４よりも中心側の領域）に存在している。このときに、ブラシ４０に接続された導電線８０を端子７０に接合する。上記のように、導電線８０を端子７０に接合する。 The brush 40 with the conductive wire 80 connected thereto is prepared, and the brush 40 is set in the brush storage section 60a with the rear end surface 44 of the brush 40 abutting against the spiral portion 51 of the brush spring 50. At this time, part of the brush 40 protrudes from the brush storage section 60a. Specifically, part of the brush 40 is present in the area where the commutator 30 is located (the area closer to the center than the third side wall 64). At this time, the conductive wire 80 connected to the brush 40 is joined to the terminal 70. The conductive wire 80 is joined to the terminal 70 as described above.
　次に、図１２の（ａ）～（ｄ）に示すように、図１１の状態からブラシ４０を移動させる。具体的には、図１２の（ｄ）に示すように、ブラシ４０の前端面４３がブラシ収納部６０ａの前方端部に位置するまでブラシ４０を移動させる。 Next, as shown in (a) to (d) of Figure 12, the brush 40 is moved from the state shown in Figure 11. Specifically, as shown in (d) of Figure 12, the brush 40 is moved until the front end surface 43 of the brush 40 is positioned at the front end of the brush storage section 60a.
　本実施の形態では、ブラシ４０がブラシ収納部６０ａに沿って１回転できるようにブラシ収納部６０ａが形成されている。これにより、ブラシ４０を回転させることで、ブラシ４０の後端面４４をブラシ収納部６０ａの奥側（図１２の矢印の方向）へと順次移動させることができる。ブラシ４０がブラシ収納部６０ａに収納されることにより、導電線８０は、ねじられた状態になる。 In this embodiment, the brush storage section 60a is formed so that the brush 40 can rotate once along the brush storage section 60a. This allows the rear end surface 44 of the brush 40 to be moved sequentially toward the back side of the brush storage section 60a (in the direction of the arrow in FIG. 12) by rotating the brush 40. When the brush 40 is stored in the brush storage section 60a, the conductive wire 80 is in a twisted state.
　このとき、図示されていないが、ブラシ４０の後端面４４に当接するブラシバネ５０の渦巻部５１は、ブラシ４０の移動とともにブラシ収納部６０ａの奥側へと移動する。その際、ブラシバネ５０の外側端部５０ａがブラシホルダ６０の固定部６０ｂに固定されているので、ブラシ４０を回転させるにしたがって、ブラシバネ５０を構成する帯状の線材は、ブラシ収納部６０ａの円弧形状に沿って渦巻部５１から引き出されていく。つまり、ブラシ４０は、ブラシバネ５０の渦巻部５１からバネ弾性力を受けながら回転する。 At this time, although not shown, the spiral portion 51 of the brush spring 50, which abuts against the rear end surface 44 of the brush 40, moves toward the rear side of the brush storage section 60a as the brush 40 moves. At that time, since the outer end portion 50a of the brush spring 50 is fixed to the fixed portion 60b of the brush holder 60, as the brush 40 rotates, the strip-shaped wire that constitutes the brush spring 50 is pulled out from the spiral portion 51 along the arc shape of the brush storage section 60a. In other words, the brush 40 rotates while receiving the spring elastic force from the spiral portion 51 of the brush spring 50.
　このように、ブラシ４０がブラシ収納部６０ａに沿って一回転してもブラシ４０に接触する障害物が存在しない。したがって、円弧状のブラシ４０と定荷重バネとを組み合わせた本構成を採用することで、電動機１の組立性を向上させることができる。 In this way, there is no obstacle that comes into contact with the brush 40 even when the brush 40 rotates once along the brush storage section 60a. Therefore, by adopting this configuration that combines the arc-shaped brush 40 with a constant load spring, the assembly of the electric motor 1 can be improved.
　その後、図示しないが、２つのブラシ４０及び２つのブラシバネ５０をブラシホルダ６０にセットした後、２つのブラシ４０及び２つのブラシバネ５０を第２ブラケット１０２に取り付ける。このように、ブラシホルダ６０と第２ブラケット１０２とは別体である。したがって、ブラシホルダ６０に複数のブラシ４０を配置する場合でも、ブラシ４０をブラシホルダ６０に保持した状態で第２ブラケット１０２に取り付けることができる。これにより、複数の円弧状のブラシ４０を用いる場合であっても、複数のブラシ４０をブラシホルダ６０に容易にセットすることができる。 Then, although not shown, the two brushes 40 and the two brush springs 50 are set in the brush holder 60, and then the two brushes 40 and the two brush springs 50 are attached to the second bracket 102. In this way, the brush holder 60 and the second bracket 102 are separate entities. Therefore, even when multiple brushes 40 are placed on the brush holder 60, the brushes 40 can be attached to the second bracket 102 while being held by the brush holder 60. This makes it possible to easily set multiple brushes 40 in the brush holder 60, even when multiple arc-shaped brushes 40 are used.
　以上のように構成される電動機１では、ブラシ４０に供給される電流（駆動電流）が、整流子３０の整流子片３１を介してコイル２２に流れる。これにより、回転子２０（コイル２２）に磁束が発生する。回転子２０に生じた磁束と固定子１０から生じる磁束との相互作用によって生じた磁気力とが、回転子２０を回転させるトルクとなる。このとき、整流子３０が有する整流子片３１とブラシ４０とが接する際の位置関係によって電流が流れる方向が切り替えられる。このように、電流が流れる方向が切り替えられることで、固定子１０と回転子２０との間に発生する磁力の反発力と吸引力とで一定方向の回転力が生成される。これにより、回転子２０が回転軸２１を中心として回転する。 In the electric motor 1 configured as described above, the current (drive current) supplied to the brushes 40 flows through the coils 22 via the commutator segments 31 of the commutator 30. This generates magnetic flux in the rotor 20 (coils 22). The magnetic force generated by the interaction between the magnetic flux generated in the rotor 20 and the magnetic flux generated from the stator 10 becomes torque that rotates the rotor 20. At this time, the direction of the current flow is switched depending on the positional relationship when the commutator segments 31 of the commutator 30 come into contact with the brushes 40. In this way, by switching the direction of the current flow, a rotational force in a fixed direction is generated by the repulsive and attractive forces of the magnetic forces generated between the stator 10 and the rotor 20. This causes the rotor 20 to rotate around the rotating shaft 21.
　図１３は、摩耗によりブラシ４０が摺動する様子を示す図である。図１３に示すように、ブラシホルダ６０のブラシ収納部６０ａに収納されたブラシ４０は、ブラシバネ５０によって整流子３０に押し付けられている。したがって、回転子２０が回転すると、整流子３０の整流子片３１との摩擦により前端部が摩耗していく。つまり、図１３の矢印に示されるように、ブラシ４０は、摩耗によって長さが短くなっていく。このため、ブラシ４０の後端面４４は、ブラシ収納部６０ａ内を整流子３０に向かって移動していく。このとき、定荷重バネであるブラシバネ５０を構成する線材は、ブラシ４０の摩耗によりブラシ４０が短くなるにつれて渦巻部５１となって巻かれていく。つまり、渦巻部５１が外側端部５０ａに近づいていく。 Figure 13 shows how the brush 40 slides due to wear. As shown in Figure 13, the brush 40 stored in the brush storage section 60a of the brush holder 60 is pressed against the commutator 30 by the brush spring 50. Therefore, when the rotor 20 rotates, the front end portion is worn down due to friction with the commutator segments 31 of the commutator 30. In other words, as shown by the arrow in Figure 13, the brush 40 becomes shorter due to wear. Therefore, the rear end surface 44 of the brush 40 moves toward the commutator 30 inside the brush storage section 60a. At this time, the wire that constitutes the brush spring 50, which is a constant-load spring, is wound up into a spiral portion 51 as the brush 40 becomes shorter due to wear. In other words, the spiral portion 51 approaches the outer end portion 50a.
　このように、ブラシ４０は、前端部が摩耗していくにしたがって、ブラシ収納部６０ａ内を整流子３０に向かって摺動する。本実施の形態では、ブラシ収納部６０ａが第１側壁６１及び第２側壁６２によって構成されている。このため、ブラシ４０は、第１側壁６１及び第２側壁６２でガイドされながら、第１側壁６１及び第２側壁６２の間を移動する。つまり、第１側壁６１及び第２側壁６２は、ブラシ４０をガイドするガイド壁として機能する。 In this way, the brush 40 slides within the brush storage section 60a toward the commutator 30 as the front end wears. In this embodiment, the brush storage section 60a is composed of a first side wall 61 and a second side wall 62. Therefore, the brush 40 moves between the first side wall 61 and the second side wall 62 while being guided by the first side wall 61 and the second side wall 62. In other words, the first side wall 61 and the second side wall 62 function as guide walls that guide the brush 40.
　図１３に示すように、ブラシ４０が第１側壁６１及び第２側壁６２の間を摺動することで、ブラシ４０を押し付けるブラシバネ５０の渦巻部５１も、整流子３０に向かって第１側壁６１及び第２側壁６２の間を移動する。具体的には、ブラシバネ５０の渦巻部５１は、第１側壁６１及び第２側壁６２でガイドされながら、第１側壁６１及び第２側壁６２の間を移動する。このように、第１側壁６１及び第２側壁６２は、ブラシバネ５０の渦巻部５１をガイドするガイド壁としても機能する。 As shown in FIG. 13, as the brush 40 slides between the first side wall 61 and the second side wall 62, the spiral portion 51 of the brush spring 50 pressing against the brush 40 also moves between the first side wall 61 and the second side wall 62 toward the commutator 30. Specifically, the spiral portion 51 of the brush spring 50 moves between the first side wall 61 and the second side wall 62 while being guided by the first side wall 61 and the second side wall 62. In this way, the first side wall 61 and the second side wall 62 also function as guide walls that guide the spiral portion 51 of the brush spring 50.
　以上説明したように、電動機１では、ブラシ４０が円弧状である。ブラシホルダ６０に取り付けられた端子７０が、ブラシ４０の内側に位置している。 As described above, in the electric motor 1, the brushes 40 are arc-shaped. The terminals 70 attached to the brush holder 60 are located on the inside of the brushes 40.
　この構成により、端子７０とブラシ４０とを電気的に接続する導電線８０の長さを短くすることができる。よって、ブラシ４０が摩耗するにつれて導電線８０が移動していったとしても、導電線８０がブラシホルダ６０の凹凸構造等に干渉してブラシ４０の荷重安定性が低下することを抑制できる。したがって、高い信頼性を有する長寿命の電動機１を実現することができる。 This configuration allows the length of the conductive wire 80 that electrically connects the terminal 70 and the brush 40 to be shortened. Therefore, even if the conductive wire 80 moves as the brush 40 wears, it is possible to prevent the conductive wire 80 from interfering with the uneven structure of the brush holder 60, etc., and reducing the load stability of the brush 40. Therefore, it is possible to realize a highly reliable, long-life electric motor 1.
　また、端子７０の少なくとも一部は、ブラシ４０の円弧を構成する円の中心に重なっている。 Furthermore, at least a portion of the terminal 70 overlaps with the center of the circle that constitutes the arc of the brush 40.
　この構成により、導電線８０の長さを最短にすることができる。したがって、ブラシ４０の荷重安定性が低下することを一層抑制できる。 This configuration allows the length of the conductive wire 80 to be minimized. This further prevents the load stability of the brush 40 from decreasing.
　また、ブラシ４０を整流子３０に押し当てるためのブラシバネ５０として定荷重バネを用いている。 In addition, a constant load spring is used as the brush spring 50 to press the brush 40 against the commutator 30.
　ブラシバネとしてトーションバネを用いると、ブラシが摩耗する前の押圧（初圧）とブラシの摩耗により、電動機が寿命に到達したときの押圧（終圧）との差が大きくなってしまう。つまり、ブラシの初期時と末期時とで整流子への押圧荷重の差が大きくなってしまう。しかも、トーションバネで円弧状のブラシを押し付けると、トーションバネによる押圧荷重によって、円弧状のブラシが外側に向けて押し付けられる。この結果、トーションバネによってブラシが整流子を押し付ける際の押圧荷重が軽減されてしまう。さらに、円弧状のブラシを整流子に押し付けるためのブラシバネとしてトーションバネを用いると、トーションバネは、円弧状のブラシの内側に配置される。このため、ブラシの内側に空きスペースが無くなる。したがって、ブラシの内側に端子を配置することが難しい。 When a torsion spring is used as a brush spring, the difference between the pressure (initial pressure) before the brush wears out and the pressure (final pressure) when the motor reaches the end of its life due to brush wear becomes large. In other words, the difference in the pressing load on the commutator becomes large between the initial and final stages of the brush's life. Furthermore, when a torsion spring presses an arc-shaped brush, the arc-shaped brush is pressed outward by the pressing load of the torsion spring. As a result, the pressing load when the brush presses the commutator by the torsion spring is reduced. Furthermore, when a torsion spring is used as a brush spring for pressing an arc-shaped brush against a commutator, the torsion spring is positioned inside the arc-shaped brush. This leaves no free space inside the brush. This makes it difficult to position terminals inside the brush.
　これに対して、本実施の形態のように、ブラシバネ５０として定荷重バネを用いることで、ブラシ４０の内側に空きスペースを設けることができる。これにより、円弧状のブラシ４０の内側に端子７０を容易に配置することができる。この場合、端子７０だけではなく、ブラシ４０の内側には、ブラシ４０と電気的に接続された電子部品（チョークコイル又はコンデンサ等）も配置することもできる。 In contrast, by using a constant load spring as the brush spring 50 as in the present embodiment, it is possible to provide an empty space inside the brush 40. This makes it easy to arrange the terminals 70 inside the arc-shaped brush 40. In this case, not only the terminals 70 but also electronic components (such as a choke coil or a capacitor) electrically connected to the brush 40 can be arranged inside the brush 40.
　しかも、ブラシバネ５０として定荷重バネを用いることで、ブラシ４０が摩耗していっても、ブラシバネ５０によってブラシ４０に一定の押圧荷重をかけることができる。これにより、ブラシ４０が摩耗する前の押圧（初圧）とブラシ４０の摩耗により、電動機１が寿命に到達したときの押圧（終圧）との差を小さくすることができる。 Furthermore, by using a constant load spring as the brush spring 50, a constant pressure load can be applied to the brush 40 by the brush spring 50 even if the brush 40 wears. This makes it possible to reduce the difference between the pressure (initial pressure) before the brush 40 wears and the pressure (final pressure) when the motor 1 reaches the end of its life due to wear of the brush 40.
　さらに、ブラシバネ５０として定荷重バネを用いた場合、本実施の形態のように、ブラシバネ５０は、渦巻部５１から引き出された帯状の線材がブラシ４０の円弧状の側面に接触するように配置される。これにより、ブラシ４０は、渦巻部５１が接する後端面４４においてブラシバネ５０からの押圧荷重を受けるだけではなく、渦巻部５１から引き出された帯状の線材とブラシ４０の円弧状の側面との接触箇所においてもブラシバネ５０からの押圧荷重を受けることができる。したがって、ブラシバネとしてトーションバネを用いたときのように、ブラシが整流子を押し付ける際の押圧荷重が軽減されることを無くすことができる。 Furthermore, when a constant load spring is used as the brush spring 50, as in this embodiment, the brush spring 50 is positioned so that the strip-shaped wire pulled out from the spiral portion 51 contacts the arc-shaped side of the brush 40. As a result, the brush 40 not only receives a pressure load from the brush spring 50 at the rear end surface 44 where the spiral portion 51 contacts, but also at the contact point between the strip-shaped wire pulled out from the spiral portion 51 and the arc-shaped side of the brush 40. Therefore, it is possible to eliminate the reduction in the pressure load when the brush presses against the commutator, as occurs when a torsion spring is used as the brush spring.
　具体的には、ブラシバネ５０は、ブラシバネ５０を構成する帯状の線材（金属板）とブラシ４０の外周側の第１側面４１とが接触するように配置されている。 Specifically, the brush spring 50 is arranged so that the strip-shaped wire material (metal plate) that constitutes the brush spring 50 is in contact with the first side surface 41 on the outer periphery of the brush 40.
　これにより、ブラシバネ５０の帯状の線材とブラシ４０の円弧状の第１側面４１との接触箇所から、整流子３０に向かう方向に押圧荷重が発生する。したがって、円弧状のブラシ４０であってもブラシ４０から整流子３０に対して安定した押圧荷重をかけることができる。つまり、ブラシ４０による安定した押圧を実現することができる。 As a result, a pressure load is generated in the direction toward the commutator 30 from the contact point between the band-shaped wire of the brush spring 50 and the arc-shaped first side surface 41 of the brush 40. Therefore, even with an arc-shaped brush 40, a stable pressure load can be applied from the brush 40 to the commutator 30. In other words, a stable pressure from the brush 40 can be achieved.
　また、ブラシバネ５０の渦巻部５１から引き出された帯状の線材とブラシ４０の円弧状の第１側面４１とが密着している。よって、ブラシバネ５０の帯状の線材とブラシ４０の第１側面４１との間に、ブラシ４０の摩耗粉が入り込むことができない。この結果、ブラシバネ５０を用いたとしても、ブラシ４０の摩耗粉によってブラシバネ５０とブラシ４０との滑り性が低下することがない。 In addition, the strip-shaped wire pulled out from the spiral portion 51 of the brush spring 50 and the arc-shaped first side surface 41 of the brush 40 are in close contact with each other. Therefore, wear powder from the brush 40 cannot get between the strip-shaped wire of the brush spring 50 and the first side surface 41 of the brush 40. As a result, even when the brush spring 50 is used, the wear powder from the brush 40 does not reduce the sliding properties between the brush spring 50 and the brush 40.
　また、ブラシ４０の内側に端子７０を配置すると、端子７０とブラシ４０とに接続された導電線８０は、ブラシ４０が摩耗するにしたがって、導電線８０と端子７０との接合部分を固定端として移動する。具体的には、導電線８０は、導電線８０と端子７０との接合部分を固定端として回転する。このとき、導電線８０は、ブラシ４０が摩耗するにしたがってねじれていくので、ブラシ４０の荷重が低下するおそれがある。 In addition, when the terminal 70 is placed inside the brush 40, the conductive wire 80 connected to the terminal 70 and brush 40 moves with the joint between the conductive wire 80 and the terminal 70 as a fixed end as the brush 40 wears. Specifically, the conductive wire 80 rotates with the joint between the conductive wire 80 and the terminal 70 as a fixed end. At this time, the conductive wire 80 twists as the brush 40 wears, which may cause the load of the brush 40 to decrease.
　そこで、電動機１では、導電線８０は、ブラシ４０が摩耗する前に予めねじられている。これにより、ブラシ４０が摩耗していくにしたがってねじれが緩和するように構成されている。 Therefore, in the electric motor 1, the conductive wire 80 is twisted in advance before the brush 40 wears. This allows the twist to be relaxed as the brush 40 wears.
　この構成により、ブラシ４０が摩耗するにしたがって導電線８０と端子７０との接合部分を固定端として導電線８０が回転移動したときに、導電線８０の回転移動とともに、導電線８０のねじれが緩和していく。これにより、導電線８０が回転移動したとしても、ブラシ４０の荷重が低下することを効果的に抑制できる。 With this configuration, when the conductive wire 80 rotates around the joint between the conductive wire 80 and the terminal 70 as the brush 40 wears, the twist in the conductive wire 80 is relaxed as the conductive wire 80 rotates. This effectively prevents the load of the brush 40 from decreasing even if the conductive wire 80 rotates.
　また、ブラシ４０が摩耗するとブラシ摩耗粉が発生するが、特に、円弧状のブラシ４０は、直線状のブラシと比べてブラシ摩耗粉が増大する。この点、本実施の形態では、整流子３０に沿って第３側壁６４が設けられている。これにより、第３側壁６４によってブラシ摩耗粉が飛散することを抑制することができる。つまり、第３側壁６４は、ブラシ摩耗粉の飛散することを抑制する防護壁として機能する。このように、ブラシホルダ６０に第３側壁６４を設けることで、ブラシ摩耗粉が目詰まりしてブラシ４０の荷重が低下することを抑制することができる。 In addition, when the brush 40 wears, brush wear powder is generated, and in particular, the arc-shaped brush 40 generates more brush wear powder than a straight brush. In this regard, in this embodiment, a third side wall 64 is provided along the commutator 30. This makes it possible to prevent brush wear powder from scattering. In other words, the third side wall 64 functions as a protective wall that prevents brush wear powder from scattering. In this way, by providing the third side wall 64 on the brush holder 60, it is possible to prevent the load of the brush 40 from decreasing due to clogging with brush wear powder.
　特に、第３側壁６４は、ブラシ４０の第２側面４２に対向する部分（ブラシ４０の内周側部分）に設けられており、且つ、ブラシ４０の第２側面４２に対向しない部分（ブラシ４０の外周側部分）には設けられていない。これにより、ブラシ４０の第２側面４２に対向しない部分にブラシ摩耗粉の飛散を促すことができる。これにより、ブラシ４０の第２側面４２に対向する部分にブラシ摩耗粉が飛散しにくくなる。つまり、ブラシ摩耗粉をブラシ４０の外周側部分へと選択的に集めることができる。したがって、ブラシ４０の内周側部分に配置された端子７０及び電子部品がブラシ摩耗粉によって、絶縁信頼性が低下することを抑制できる。例えば、電子部品がショート等して電磁両立性（Ｅｌｅｃｔｒｏｍａｇｎｅｔｉｃ　Ｃｏｍｐａｔｉｂｉｌｉｔｙ（ＥＭＣ））が低下することを抑制できる。 In particular, the third side wall 64 is provided in the portion facing the second side surface 42 of the brush 40 (the inner peripheral portion of the brush 40), and is not provided in the portion not facing the second side surface 42 of the brush 40 (the outer peripheral portion of the brush 40). This can encourage the scattering of brush wear powder to the portion not facing the second side surface 42 of the brush 40. This makes it difficult for brush wear powder to scatter to the portion facing the second side surface 42 of the brush 40. In other words, the brush wear powder can be selectively collected to the outer peripheral portion of the brush 40. Therefore, it is possible to prevent the insulation reliability of the terminals 70 and electronic components arranged in the inner peripheral portion of the brush 40 from being reduced by the brush wear powder. For example, it is possible to prevent the electronic components from shorting out, etc., and thereby reducing the electromagnetic compatibility (EMC).
　また、本実施の形態では、切削加工を施すことなく作製した円弧状のブラシ４０を用いている。円弧状のブラシ４０を高い寸法精度で加工するには、粉末を圧縮成型して焼成して得られた焼結体に切削加工を施す。しかし、円弧状の焼結体に対して切削加工を施すことは難しい。このため、高い寸法精度を有する円弧状のブラシ４０を作製するには、製造コストが大きくかかる。そこで、本実施の形態では、切削加工を施すことなく円弧状のブラシ４０を作製している。これにより、低コストでブラシ４０を作製することができる。したがって、低コストの電動機１を実現することができる。 In addition, in this embodiment, the arc-shaped brush 40 is made without cutting. To process the arc-shaped brush 40 with high dimensional accuracy, a sintered body obtained by compressing and sintering powder is cut. However, it is difficult to cut an arc-shaped sintered body. For this reason, the manufacturing costs are high to make an arc-shaped brush 40 with high dimensional accuracy. Therefore, in this embodiment, the arc-shaped brush 40 is made without cutting. This allows the brush 40 to be made at low cost. Therefore, a low-cost electric motor 1 can be realized.
　また、電動機１では、長さが長い円弧状のブラシ４０を用いている。具体的には、ブラシ４０の円弧をなす円の中心の中心点とブラシ４０の前端面４３とを結ぶ線と、ブラシ４０の円弧をなす円の中心の中心点とブラシ４０の後端面４４とを結ぶ線とのなす角が、９０°以上になっている。 The motor 1 also uses a long, arc-shaped brush 40. Specifically, the angle between the line connecting the center point of the circle that forms the arc of the brush 40 to the front end surface 43 of the brush 40 and the line connecting the center point of the circle that forms the arc of the brush 40 to the rear end surface 44 of the brush 40 is 90° or more.
　このように長さが長い円弧状のブラシ４０に対して、ブラシバネとしてトーションバネを用いると、ブラシバネによるブラシ４０への押圧荷重が安定せずに寿命及び品質が低下するおそれがある。しかし、電動機１のようにブラシバネ５０として定荷重バネを用いることで、長さが長い円弧状のブラシ４０を用いる場合であっても、ブラシ４０への押圧荷重を安定させることができる。したがって、長寿命及び高品質の電動機１を実現することができる。 If a torsion spring is used as the brush spring for such a long, arc-shaped brush 40, the pressing load applied to the brush 40 by the brush spring may not be stable, resulting in a reduced lifespan and quality. However, by using a constant-load spring as the brush spring 50 as in the case of the electric motor 1, the pressing load on the brush 40 can be stabilized even when a long, arc-shaped brush 40 is used. This makes it possible to realize an electric motor 1 with a long lifespan and high quality.
　以上のように、本実施の形態に係る電動機１は、軸心Ｃが延伸する方向を軸心方向とする回転軸２１と、回転軸２１に取り付けられた整流子３０と、整流子３０に接するブラシ４０と、ブラシ４０を保持するブラシホルダ６０と、ブラシホルダ６０に取り付けられた端子７０と、一方の端部がブラシ４０に接続され、他方の端部が端子と電気的に接続された導電線と、を備える。ブラシ４０は、円弧状である。端子７０は、ブラシ４０の内側に位置している。 As described above, the electric motor 1 according to this embodiment includes the rotating shaft 21 whose axial direction is the direction in which the axis C extends, the commutator 30 attached to the rotating shaft 21, the brush 40 in contact with the commutator 30, the brush holder 60 that holds the brush 40, the terminal 70 attached to the brush holder 60, and a conductive wire having one end connected to the brush 40 and the other end electrically connected to the terminal. The brush 40 is arc-shaped. The terminal 70 is located inside the brush 40.
　これにより、円弧状のブラシを用いた電動機であっても、ブラシに接続された導電線によってブラシの荷重安定性が低下してしまうことを抑制できる。 This makes it possible to prevent the load stability of the brush from being reduced by the conductive wire connected to the brush, even in motors that use arc-shaped brushes.
　（実施の形態２）
　次に、実施の形態２に係る電動機１Ａについて、図１４及び図１５を用いて説明する。図１４は、実施の形態２に係る電動機１Ａにおいて、ブラシ４０Ａ及びブラシバネ５０が配置されたブラシホルダ６０の上面図である。図１５は、図１４におけるブラシ４０Ａの前端面４３と整流子３０とが接触する箇所及びその周辺部分の拡大図である。 (Embodiment 2)
Next, an electric motor 1A according to a second embodiment will be described with reference to Fig. 14 and Fig. 15. Fig. 14 is a top view of a brush holder 60 in which brushes 40A and brush springs 50 are arranged in an electric motor 1A according to a second embodiment. Fig. 15 is an enlarged view of a contact point between a front end surface 43 of brush 40A and commutator 30 and the surrounding area in Fig. 14.
　上記実施の形態１における電動機１では、ブラシ４０の前端面４３と整流子３０とが接触する箇所において、ブラシ４０の接線と電動機１の回転方向とのなす角度は、９０°である（図５Ｂの拡大部分を参照）。しかし、本実施の形態における電動機１Ａでは、ブラシ４０Ａの前端面４３と整流子３０とが接触する箇所において、ブラシ４０Ａの接線と電動機１の回転方向とのなす角度θ（図１５を参照）は、９０°未満になっている。角度θは、４５°よりも大きくなっているとよい。つまり、角度θは、４５°＜θ＜９０°であるとよい。 In the electric motor 1 in the first embodiment, at the point where the front end surface 43 of the brush 40 contacts the commutator 30, the angle between the tangent of the brush 40 and the direction of rotation of the electric motor 1 is 90° (see the enlarged portion in FIG. 5B). However, in the electric motor 1A in this embodiment, at the point where the front end surface 43 of the brush 40A contacts the commutator 30, the angle θ (see FIG. 15) between the tangent of the brush 40A and the direction of rotation of the electric motor 1 is less than 90°. It is preferable that the angle θ be greater than 45°. In other words, it is preferable that the angle θ be 45°<θ<90°.
　それ以外の構成については、基本的には、本実施の形態における電動機１Ａは、上記実施の形態１における電動機１と同様である。 　Other than that, the configuration of the electric motor 1A in this embodiment is basically the same as the electric motor 1 in the above-mentioned embodiment 1.
　したがって、本実施の形態においても、上記実施の形態１における電動機１と同様の効果を奏する。例えば、本実施の形態に係る電動機１Ａにおいても、端子７０が円弧状のブラシ４０Ａの内側に位置しているので、ブラシ４０Ａの荷重安定性が低下することを抑制できる等の効果を奏する。 Therefore, this embodiment also provides the same effects as the electric motor 1 in the first embodiment. For example, in the electric motor 1A according to this embodiment, the terminal 70 is located inside the arc-shaped brush 40A, so that it provides the effect of preventing the load stability of the brush 40A from decreasing.
　電動機１Ａでは、ブラシ４０Ａの接線と電動機１の回転方向とのなす角度θが９０°未満になっている。 In electric motor 1A, the angle θ between the tangent of brush 40A and the direction of rotation of electric motor 1 is less than 90°.
　この構成により、ブラシ４０Ａの円弧をなす円の直径を大きくすることができる。つまり、ブラシ４０Ａの長さを、上記実施の形態１におけるブラシ４０の長さよりも長くすることができる。これにより、電動機１Ａの長寿命化を図ることができる。この際、長くなったブラシ４０Ａを電動機１Ａの内部スペースを有効活用して配置することで、電動機１Ａの外形を大きくすることなく、電動機１Ａの長寿命化を図ることができる。つまり、長寿命で小型の電動機１Ａを実現することができる。 This configuration allows the diameter of the circle forming the arc of brush 40A to be increased. In other words, the length of brush 40A can be made longer than the length of brush 40 in the first embodiment above. This allows the life of motor 1A to be extended. In this case, by arranging the longer brush 40A to effectively utilize the internal space of motor 1A, the life of motor 1A can be extended without increasing the external dimensions of motor 1A. In other words, a compact motor 1A with a long life can be realized.
　円弧状のブラシ４０Ａを整流子３０に押し付けるためのブラシバネとしてトーションバネを用いると、ブラシ４０Ａの第２側面４２（内周面）側に荷重が強くなって、ブラシ４０に対する荷重が偏ってしまう。一方、ブラシバネ５０として定荷重バネを用いることで、ブラシ４０Ａの第１側面４１（外周面）側に荷重が偏ってしまう。そこで、ブラシ４０Ａの接線と電動機１の回転方向とのなす角度θを９０°未満にすることで、ブラシ４０Ａの前端部と後端部との荷重を一定に近づけることができる。これにより、整流子３０に適した荷重を整流子３０に与えることができる。 If a torsion spring is used as the brush spring for pressing the arc-shaped brush 40A against the commutator 30, the load will be strong on the second side 42 (inner peripheral surface) of the brush 40A, and the load on the brush 40 will be biased. On the other hand, if a constant load spring is used as the brush spring 50, the load will be biased on the first side 41 (outer peripheral surface) of the brush 40A. Therefore, by making the angle θ between the tangent of the brush 40A and the direction of rotation of the motor 1 less than 90°, the load on the front and rear ends of the brush 40A can be made closer to constant. This makes it possible to apply a load appropriate for the commutator 30 to the commutator 30.
　（実施の形態３）
　実施の形態３に係る電動機１Ｂについて、図１６、図１７及び図１８を用いて説明する。図１６は、実施の形態３に係る電動機１Ｂにおいて、ブラシ４０Ｂ及びブラシバネ５０が配置されたブラシホルダ６０の斜視図である。図１７は、図１６におけるブラシ４０Ｂの後端部及びその周辺部分の拡大図である。図１８は、実施の形態３に係る電動機１Ｂが備えるブラシ４０Ｂ及び導電線８０の斜視図である。 (Embodiment 3)
An electric motor 1B according to the third embodiment will be described with reference to Figs. 16, 17 and 18. Fig. 16 is a perspective view of a brush holder 60 in which a brush 40B and a brush spring 50 are arranged in the electric motor 1B according to the third embodiment. Fig. 17 is an enlarged view of a rear end portion of the brush 40B and its surrounding area in Fig. 16. Fig. 18 is a perspective view of the brush 40B and conductive wire 80 provided in the electric motor 1B according to the third embodiment.
　電動機１Ｂは、上記実施の形態１に係る電動機１に対して、ブラシ４０Ｂの形状と、ブラシ４０Ｂ及びブラシバネ５０の連結構造とが異なる。 The electric motor 1B differs from the electric motor 1 according to the first embodiment in the shape of the brush 40B and the connection structure between the brush 40B and the brush spring 50.
　具体的には、図１６～図１８に示すように、ブラシ４０Ｂは、突起４５と、溝４６とを有する。突起４５には、ブラシバネ５０の渦巻部５１が挿入される。溝４６には、突起４５に挿入された渦巻部５１における線材が巻回された部分（線材の積層部分）が差し込まれる。つまり、ブラシバネ５０の渦巻部５１は、ブラシ４０Ｂの突起４５に巻回された構成になっている。 Specifically, as shown in Figures 16 to 18, brush 40B has protrusion 45 and groove 46. Spiral portion 51 of brush spring 50 is inserted into protrusion 45. The groove 46 is fitted with the wound portion of wire in spiral portion 51 inserted into protrusion 45 (laminated portion of wire). In other words, spiral portion 51 of brush spring 50 is wound around protrusion 45 of brush 40B.
　ブラシ４０Ｂにおける突起４５は、ブラシ４０Ｂの後端部の上面に形成されている。突起４５は、円柱状に形成されている。突起４５の上面視形状は、円形である。円柱状の突起４５の中心軸は、回転軸２１の軸心Ｃと平行である。導電線８０は、突起４５の中心に固定されている。したがって、上面視において、ブラシ４０Ｂと導電線８０との接続部は、ブラシバネ５０の渦巻部５１の内側に位置している。溝４６は、突起４５の前方側に形成されている。 The protrusion 45 of the brush 40B is formed on the upper surface of the rear end of the brush 40B. The protrusion 45 is formed in a cylindrical shape. The shape of the protrusion 45 when viewed from above is circular. The central axis of the cylindrical protrusion 45 is parallel to the axis C of the rotating shaft 21. The conductive wire 80 is fixed to the center of the protrusion 45. Therefore, when viewed from above, the connection portion between the brush 40B and the conductive wire 80 is located inside the spiral portion 51 of the brush spring 50. The groove 46 is formed on the front side of the protrusion 45.
　このようにブラシ４０Ｂに配置されたブラシバネ５０は、渦巻部５１の内周面でブラシ４０Ｂに押圧を付与している。具体的には、ブラシバネ５０は、渦巻部５１におけるブラシ４０Ｂの後端面４４側の内周面でブラシ４０Ｂに押圧を付与している。 The brush spring 50 thus arranged on the brush 40B applies pressure to the brush 40B on the inner circumferential surface of the spiral portion 51. Specifically, the brush spring 50 applies pressure to the brush 40B on the inner circumferential surface of the spiral portion 51 on the rear end surface 44 side of the brush 40B.
　それ以外の構成については、基本的には、電動機１Ｂは、上記実施の形態１における電動機１と同様である。 Other than that, the configuration of the electric motor 1B is basically the same as that of the electric motor 1 in the first embodiment described above.
　したがって、電動機１Ｂは、上記実施の形態１における電動機１と同様の効果を奏する。例えば、電動機１Ｂにおいても、端子７０が円弧状のブラシ４０Ｂの内側に位置している。したがって、ブラシ４０Ｂの荷重安定性が低下することを抑制できる等の効果を奏する。 Therefore, the electric motor 1B has the same effect as the electric motor 1 in the first embodiment. For example, in the electric motor 1B, the terminal 70 is also located inside the arc-shaped brush 40B. This has the effect of preventing the load stability of the brush 40B from decreasing.
　また、電動機１Ｂにおいても、定荷重バネであるブラシバネ５０は、ブラシ４０Ｂの第１側面４１（外周側の側面）に接触するように配置されている。 In the electric motor 1B, the brush spring 50, which is a constant force spring, is also positioned so that it contacts the first side surface 41 (the side surface on the outer periphery) of the brush 40B.
　仮にブラシバネ５０をブラシ４０Ｂの第２側面４２（内周側の側面）に接触するように配置すると、ブラシ４０Ｂが摩耗するにつれて渦巻部５１の外径が大きくなってブラシバネ５０を構成する帯状の線材が塑性変形したときに、その塑性変形量が２倍以上になってしまう。そこで、ブラシ４０Ｂの溝４６の幅Ｗを大きくしておくことも考えられる。しかし、溝４６の幅Ｗを大きくし過ぎると、ブラシ４０Ｂの有効摩耗長が減ってしまう。そこで、本実施の形態のように、ブラシバネ５０をブラシ４０Ｂの第１側面４１に接触するように配置することで、ブラシ４０Ｂの溝４６の幅Ｗをあまり大きくすることなく、ブラシバネ５０を構成する帯状の線材の塑性変形量を小さくすることができる。 If the brush spring 50 were arranged so as to contact the second side surface 42 (the side surface on the inner circumference) of the brush 40B, when the outer diameter of the spiral portion 51 increases as the brush 40B wears and the band-shaped wire material constituting the brush spring 50 undergoes plastic deformation, the amount of plastic deformation would be more than doubled. Therefore, it is possible to increase the width W of the groove 46 of the brush 40B. However, if the width W of the groove 46 is made too large, the effective wear length of the brush 40B will be reduced. Therefore, as in this embodiment, by arranging the brush spring 50 so as to contact the first side surface 41 of the brush 40B, the amount of plastic deformation of the band-shaped wire material constituting the brush spring 50 can be reduced without increasing the width W of the groove 46 of the brush 40B too much.
　渦巻部５１の外径が４ｍｍでステンレス製のブラシバネ５０の場合、溝４６の幅Ｗは、渦巻部５１における線材が巻回された部分の厚みの１．３倍以上２倍以下であるとよい。これにより、ブラシバネ５０を構成する帯状の線材の塑性変形量を１．５倍程度許容することができる。 In the case of a stainless steel brush spring 50 with an outer diameter of the spiral portion 51 of 4 mm, the width W of the groove 46 should be between 1.3 and 2 times the thickness of the portion of the spiral portion 51 where the wire is wound. This allows the amount of plastic deformation of the strip-shaped wire that makes up the brush spring 50 to be about 1.5 times larger.
　また、電動機１Ｂでは、定荷重バネであるブラシバネ５０は、渦巻部５１の内周面でブラシ４０Ｂに押圧を付与している。上面視において、ブラシバネ５０は、ブラシ４０Ｂと導電線８０との接続部が渦巻部５１の内側に位置している。 In addition, in the electric motor 1B, the brush spring 50, which is a constant-load spring, applies pressure to the brush 40B with the inner circumferential surface of the spiral portion 51. When viewed from above, the brush spring 50 has a connection portion between the brush 40B and the conductive wire 80 located inside the spiral portion 51.
　この構成により、ブラシ４０Ｂの有効摩耗長を最長にすることができる。また、ブラシ４０Ｂによる整流子３０への押圧（バネ荷重）を安定化させることができる。しかも、ブラシバネ５０の渦巻部５１をブラシ４０Ｂの突起４５に挿入して嵌め込むことでブラシバネ５０をブラシ４０Ｂに連結できるので、ブラシ４０Ｂをブラシホルダ６０に容易にセットすることができる。 This configuration maximizes the effective wear length of the brush 40B. It also stabilizes the pressure (spring load) applied by the brush 40B to the commutator 30. Moreover, the brush spring 50 can be connected to the brush 40B by inserting and fitting the spiral portion 51 of the brush spring 50 into the protrusion 45 of the brush 40B, so that the brush 40B can be easily set in the brush holder 60.
　（変形例）
　以上、本開示に係る電動機について、実施の形態１～３に基づいて説明した、しかし、本開示は、上記実施の形態１～３に限定されるものではない。 (Modification)
The electric motor according to the present disclosure has been described above based on the first to third embodiments. However, the present disclosure is not limited to the first to third embodiments.
　例えば、上記実施の形態１～３では、ブラシ４０、４０Ａ及び４０Ｂは、２つ配置されている。しかし、これに限らない。図１９は、変形例に係る電動機１Ｃにおけるブラシ４０の配置を説明するための図である。図１９に示される電動機１Ｃのように、円弧状のブラシ４０は、４個配置されていてもよい。ブラシバネとしてトーションバネを用いた場合、電動機の外形サイズを大きくしなければ、スペースの問題から円弧状のブラシを４個配置することが困難であった。しかし、上記実施の形態１～３のように、ブラシバネ５０として定荷重バネを用いるとともに、端子７０を円弧状のブラシ４０の内側に配置することで、図１９に示すように、電動機１Ｃの外形サイズを大きくすることなく、４個の円弧状のブラシ４０を配置することができる。つまり、電動機１のスペースを有効活用してさらに長寿命化を図ることができる。一例として、４個のブラシ４０は、回転方向において等間隔（０°、９０°、１８０°２７０°）に配置するとよい。これにより、電動機１Ｃのスペースも最大限有効活用することができる。４個のブラシ４０を用いた場合に最も長寿命な電動機１Ｃを実現することができる。４個のブラシ４０を用いる場合、電動機１Ｃの極数は、４ｎとすることができる（ｎは、１以上の整数である）。 For example, in the above-mentioned embodiments 1 to 3, two brushes 40, 40A and 40B are arranged. However, this is not limited to this. FIG. 19 is a diagram for explaining the arrangement of the brushes 40 in the electric motor 1C according to the modified example. As in the electric motor 1C shown in FIG. 19, four arc-shaped brushes 40 may be arranged. When a torsion spring is used as the brush spring, it is difficult to arrange four arc-shaped brushes due to space issues unless the external size of the electric motor is increased. However, as in the above-mentioned embodiments 1 to 3, by using a constant-load spring as the brush spring 50 and arranging the terminal 70 inside the arc-shaped brush 40, as shown in FIG. 19, four arc-shaped brushes 40 can be arranged without increasing the external size of the electric motor 1C. In other words, the space of the electric motor 1 can be effectively utilized to further extend the life of the electric motor 1. As an example, the four brushes 40 may be arranged at equal intervals (0°, 90°, 180°, 270°) in the rotation direction. This allows the space of the electric motor 1C to be used as effectively as possible. The longest-lasting motor 1C can be achieved by using four brushes 40. When using four brushes 40, the number of poles of the motor 1C can be 4n (n is an integer equal to or greater than 1).
　上記実施の形態１～３において、電動機１～１Ｂは、固定子１０及び回転子２０がコアを有していないコアレスモータである。しかし、これに限らない。例えば、電動機１は、固定子１０及び回転子２０がコアを有する電動機であってもよい。 In the above embodiments 1 to 3, the electric motors 1 to 1B are coreless motors in which the stator 10 and the rotor 20 do not have cores. However, this is not limited to this. For example, the electric motor 1 may be an electric motor in which the stator 10 and the rotor 20 have cores.
　上記実施の形態１～３において、固定子１０は、永久磁石のみによって構成されている。しかし、これに限らない。例えば、固定子１０は、永久磁石と鉄心とによって構成された固定子であってもよいし、永久磁石を用いずに固定子巻線と鉄心とからなる電機子であってもよい。 In the above embodiments 1 to 3, the stator 10 is composed of only permanent magnets. However, this is not limited to this. For example, the stator 10 may be a stator composed of a permanent magnet and an iron core, or an armature composed of a stator winding and an iron core without using permanent magnets.
　上記実施の形態１～３において、電動機１～１Ｂは、厚みが外径より小さい外形サイズの扁平型のフラットモータである。しかし、これに限らない。本開示の技術は、例えば、厚みが外径よりも大きい外形サイズの円筒状の筐体を有する寸胴型の電動機等にも適用することができる。 In the above-mentioned embodiments 1 to 3, the electric motors 1 to 1B are flat motors with an outer size whose thickness is smaller than the outer diameter. However, this is not limited to this. The technology disclosed herein can also be applied to, for example, a cylindrical electric motor having a cylindrical housing with an outer size whose thickness is larger than the outer diameter.
　上記実施の形態１～３において、固定子１０及び回転子２０が発生する主磁束の向きは、回転軸２１の軸心Ｃ方向である。しかし、これに限らない。具体的には、固定子１０及び回転子２０が発生する主磁束の向きは、回転軸２１の軸心Ｃ方向と直交する方向（回転軸２１の回転の径方向）であってもよい。例えば、本開示の技術は、回転子２０が固定子１０の内側に配置されたインナーロータ型のモータに適用することもできる。 In the above-mentioned embodiments 1 to 3, the direction of the main magnetic flux generated by the stator 10 and the rotor 20 is the direction of the axis C of the rotating shaft 21. However, this is not limited to this. Specifically, the direction of the main magnetic flux generated by the stator 10 and the rotor 20 may be a direction perpendicular to the direction of the axis C of the rotating shaft 21 (the radial direction of the rotation of the rotating shaft 21). For example, the technology disclosed herein can also be applied to an inner rotor type motor in which the rotor 20 is arranged inside the stator 10.
　上記実施の形態１～３において、電動機１～１Ｂは、車両に用いられる車両用モータである。しかし、これに限らない。本開示の技術は、例えば、電気掃除機等に搭載される電動送風機等に用いられる電動機など、その他の種々の電気機器に用いられる電動機にも適用することができる。 In the above embodiments 1 to 3, the electric motors 1 to 1B are vehicle motors used in vehicles. However, this is not limited to this. The technology disclosed herein can also be applied to electric motors used in various other electrical devices, such as electric motors used in electric blowers mounted on electric vacuum cleaners, etc.
　その他、上記実施の形態１～３及び変形例に対して当業者が思い付く各種変形を施して得られる形態、又は、本開示の趣旨を逸脱しない範囲で実施の形態１～３及び変形例における構成要素及び機能を任意に組み合わせることで実現される形態も本開示に含まれる。また、本願出願時の請求の範囲に記載された複数の請求項の各々における１つ又は複数の構成要素を任意に組み合わせたものも本開示に含まれる。また、本願出願時の請求の範囲に記載された引用形式請求項を、任意の複数の請求項を引用するようにマルチクレーム又はマルチマルチクレームとしたときに、そのマルチクレーム又はマルチマルチクレームに含まれる全ての請求項の組み合わせの発明も本開示に含まれる。 In addition, this disclosure also includes forms obtained by applying various modifications that a person skilled in the art would conceive of to the above-mentioned embodiments 1 to 3 and modifications, or forms realized by arbitrarily combining the components and functions of embodiments 1 to 3 and modifications without departing from the spirit of this disclosure. In addition, this disclosure also includes any combination of one or more components in each of the multiple claims described in the claims at the time of filing this application. In addition, when a cited-form claim described in the claims at the time of filing this application is made into a multiple claim or multiple-multi claim so as to cite any multiple claims, this disclosure also includes inventions of combinations of all claims included in that multiple claim or multiple-multi claim.
　本開示の技術は、自動車等の電装分野及び家庭用電気機器分野の製品をはじめとして、電動機が搭載される種々の製品に広く利用することができる。 The technology disclosed herein can be widely used in a variety of products equipped with electric motors, including products in the electrical equipment field such as automobiles and in the field of household electrical appliances.
　１、１Ａ、１Ｂ、１Ｃ　電動機
　１０　固定子
　２０　回転子
　２１　回転軸
　２１ａ　第１端部
　２１ｂ　第２端部
　２２　コイル
　２３　モールド樹脂
　２４　円筒部材
　３０　整流子
　３１　整流子片
　４０、４０Ａ、４０Ｂ　ブラシ
　４１　第１側面
　４２　第２側面
　４３　前端面
　４４　後端面
　４５　突起
　４６　溝
　５０　ブラシバネ
　５０ａ　外側端部
　５０ｂ　内側端部
　５１　渦巻部
　６０　ブラシホルダ
　６０ａ　ブラシ収納部
　６０ｂ　固定部
　６１　第１側壁
　６２　第２側壁
　６３　底壁
　６４　第３側壁
　６５　貫通孔
　７０　端子
　８０　導電線
　８０ａ　第１端部
　８０ｂ　第２端部
　９１　第１軸受け
　９２　第２軸受け
　１０１　第１ブラケット
　１０２　第２ブラケット
　１１０　カバープレート 1, 1A, 1B, 1C Electric motor 10 Stator 20 Rotor 21 Rotating shaft 21a First end 21b Second end 22 Coil 23 Molded resin 24 Cylindrical member 30 Commutator 31 Commutator segment 40, 40A, 40B Brush 41 First side surface 42 Second side surface 43 Front end surface 44 Rear end surface 45 Protrusion 46 Groove 50 Brush spring 50a Outer end 50b Inner end 51 Spiral portion 60 Brush holder 60a Brush storage portion 60b Fixing portion 61 First side wall 62 Second side wall 63 Bottom wall 64 Third side wall 65 Through hole 70 Terminal 80 Conductive wire 80a First end 80b Second end 91 First bearing 92 Second bearing 101 First bracket 102 Second bracket 110 Cover plate

Claims (17)

  1. 　軸心が延伸する方向を軸心方向とする回転軸と、
    　前記回転軸に取り付けられた整流子と、
    　前記整流子に接するブラシと、
    　前記ブラシを保持するブラシホルダと、
    　前記ブラシホルダに取り付けられた端子と、
    　一方の端部が前記ブラシに接続され、他方の端部が前記端子と電気的に接続された導電線と、を備え、
    　前記ブラシは、円弧状であり、
    　前記端子は、前記ブラシの内側に位置している、
    　電動機。     A rotation axis having an axial direction in a direction in which the axis extends;
    A commutator attached to the rotating shaft;
    A brush in contact with the commutator;
    A brush holder for holding the brush;
    A terminal attached to the brush holder;
    a conductive wire having one end connected to the brush and the other end electrically connected to the terminal;
    The brush is arc-shaped,
    The terminal is located inside the brush.
    Electric motor.
  2. 　前記ブラシの上面視形状は、円弧をなす形状であり、
    　上面視において、前記端子の少なくとも一部は、前記円弧を構成する円の中心に重なっている、
    　請求項１に記載の電動機。     The brush has a circular arc shape when viewed from above,
    When viewed from above, at least a portion of the terminal overlaps with a center of a circle that constitutes the arc.
    2. The electric motor according to claim 1.
  3. 　前記ブラシを前記整流子に押し当てるブラシバネをさらに備え、
    　前記ブラシバネは、定荷重バネである、
    　請求項１又は２に記載の電動機。     A brush spring is further provided to press the brush against the commutator.
    The brush spring is a constant force spring.
    3. The electric motor according to claim 1 or 2.
  4. 　前記定荷重バネは、前記ブラシの外周側の側面に接触して配置されている、
    　請求項３に記載の電動機。     The constant force spring is disposed in contact with a side surface of the outer circumferential side of the brush.
    4. The electric motor according to claim 3.
  5. 　前記導電線は、前記ブラシが摩耗する前に予めねじられている、
    　請求項１又は２に記載の電動機。     The conductive wire is pre-twisted before the brush is worn.
    3. The electric motor according to claim 1 or 2.
  6. 　前記ブラシホルダは、前記整流子に沿って設けられた壁を有し、
    　前記壁は、前記整流子における前記ブラシの内周側の側面に対向する部分に設けられているが、前記整流子における前記ブラシの内周側の側面に対向しない部分には設けられていない、
    　請求項１又は２に記載の電動機。     The brush holder has a wall provided along the commutator,
    the wall is provided at a portion of the commutator facing the inner peripheral side surface of the brush, but is not provided at a portion of the commutator not facing the inner peripheral side surface of the brush;
    3. The electric motor according to claim 1 or 2.
  7. 　前記ブラシの内側に、前記ブラシと電気的に接続された電子部品が配置されている、
    　請求項１又は２に記載の電動機。     An electronic component electrically connected to the brush is disposed inside the brush.
    3. The electric motor according to claim 1 or 2.
  8. 　前記ブラシの前端面と前記整流子とが接触する箇所において、前記ブラシの接線と前記電動機の回転方向とのなす角度は、９０°未満である、
    　請求項１又は２に記載の電動機。     At a point where the front end surface of the brush contacts the commutator, an angle between a tangent of the brush and a rotation direction of the motor is less than 90°.
    3. The electric motor according to claim 1 or 2.
  9. 　前記ブラシホルダは、前記ブラシを収納するブラシ収納部を有し、
    　前記ブラシ収納部は、前記ブラシが前記ブラシ収納部に沿って１回転できる形状を成す、
    　請求項１又は２に記載の電動機。     The brush holder has a brush storage portion that stores the brush,
    The brush housing is shaped so that the brush can rotate once along the brush housing.
    3. The electric motor according to claim 1 or 2.
  10. 　前記ブラシは、複数配置されている、
    　請求項１又は２に記載の電動機。     The brush is arranged in plurality.
    3. The electric motor according to claim 1 or 2.
  11. 　前記ブラシは、４個配置されている、
    　請求項１０に記載の電動機。     The brushes are arranged in four pieces.
    11. The electric motor according to claim 10.
  12. 　前記電動機の極数は、４ｎである（ｎは、１以上の整数である）
    　請求項１１に記載の電動機。     The number of poles of the motor is 4n (n is an integer equal to or greater than 1).
    12. The electric motor according to claim 11.
  13. 　前記ブラシホルダとは別体のブラケットをさらに備え、
    　前記ブラシホルダは、複数の前記ブラシを保持した状態で前記ブラケットに取り付け可能に構成されている、
    　請求項１０に記載の電動機。     A bracket separate from the brush holder is further provided,
    The brush holder is configured to be attachable to the bracket while holding a plurality of the brushes.
    11. The electric motor according to claim 10.
  14. 　前記定荷重バネは、帯状の線材が渦巻状に巻回された渦巻部を有し、
    　前記定荷重バネは、前記渦巻部の内周面で前記ブラシに接する、
    　請求項３に記載の電動機。     The constant force spring has a spiral portion in which a strip-shaped wire is wound in a spiral shape,
    The constant force spring contacts the brush at an inner circumferential surface of the spiral portion.
    4. The electric motor according to claim 3.
  15. 　上面視において、前記ブラシと前記導電線との接続部は、前記渦巻部の内側に位置している、
    　請求項１４に記載の電動機。     When viewed from above, a connection portion between the brush and the conductive wire is located inside the spiral portion.
    15. The electric motor of claim 14.
  16. 　前記ブラシは、前記渦巻部が挿入される突起と、前記突起に挿入された前記渦巻部における前記線材が巻回された部分が差し込まれる溝とを有する、
    　請求項１４に記載の電動機。     The brush has a protrusion into which the spiral portion is inserted, and a groove into which a portion of the spiral portion around which the wire is wound is inserted when the protrusion is inserted.
    15. The electric motor of claim 14.
  17. 　前記溝の幅は、前記渦巻部における前記線材が巻回された部分の厚みの１．３倍以上２倍以下である、
    　請求項１６に記載の電動機。     The width of the groove is 1.3 times or more and 2 times or less the thickness of the portion of the spiral portion around which the wire is wound.
    17. The electric motor of claim 16.
PCT/JP2023/032158 2022-10-19 2023-09-01 Electric motor WO2024084844A1 (en)

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Application Number Priority Date Filing Date Title
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JP2022167861 2022-10-19

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Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5434463A (en) * 1994-04-21 1995-07-18 Siemens Electric Limited Direct current motor with crescent shaped brushes
JP2006166698A (en) * 2004-11-10 2006-06-22 Black & Decker Inc Brush assembly including energizing component for impacting force

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5434463A (en) * 1994-04-21 1995-07-18 Siemens Electric Limited Direct current motor with crescent shaped brushes
JP2006166698A (en) * 2004-11-10 2006-06-22 Black & Decker Inc Brush assembly including energizing component for impacting force

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