JP6615690B2 - DC motor - Google Patents

Description

The present invention relates to a DC motor.

  In a DC motor, electromagnetic noise is generated due to the contact state between the brush and the commutator and the current rectifying action. As a method for removing electromagnetic noise, a method of mounting a choke coil on a power circuit of a DC motor or a method of mounting both a choke coil and a capacitor is common. Since the removal effect can be obtained by mounting the above components in the vicinity of the brush of the noise generating unit, the components are mounted on the brush holder of the DC motor.

  For example, as described in Patent Document 1, a choke coil electrically connected to the positive terminal is electrically connected to the brush via a pigtail wire which is a bag knitted soft copper wire connected to the brush. Similarly, a choke coil is electrically connected between the cathode terminal and the brush.

JP 2008-252972 A

  By the way, when a DC motor with electromagnetic noise elimination measures is mounted on a vehicle, for example, the mounting space of the vehicle is generally limited and downsizing of the DC motor is indispensable. I need it. Therefore, the choke coil and the pigtail line are adjacent to each other at a very close position.

  However, the choke coil is formed of enamel-coated copper wire, and the enamel coating sometimes has pinholes where the base copper is exposed on the surface. As described above, the pigtail wire and the choke coil provided on the brush are adjacent to each other, and the pigtail wire is formed of bag knitted soft copper wire, so the shape is indefinite, and the choke coil copper ground surface where the pigtail wire is exposed May cause a short circuit or inductance change on the circuit, and an effective noise removal effect may not be obtained.

  Further, in a DC motor, brush wear powder is generated with the sliding contact between the brush and the commutator. Since the brush wear powder is conductive, it may not be possible to obtain an effective noise removal effect as described above by adhering and accumulating between the copper ground of the choke coil or between the choke coil and the pigtail wire.

  An object of the present invention is to provide a small DC motor while obtaining an effective noise removal effect by mounting a choke coil on a brush holder.

  In order to solve the above problems, a DC motor according to the present invention includes a brush that feeds a commutator, a wiring connected to the brush, a choke coil connected to the wiring, the brush and the choke coil. A base formed of an insulating material to be mounted and a cap formed of an insulating material covering the outer periphery of the choke coil, and the base when viewed from a direction perpendicular to the mounting surface of the choke coil of the base Forms a taper that overlaps a portion of the cap.

  According to the present invention, it is possible to provide a small DC motor while improving the reliability of a choke coil necessary for removing electromagnetic noise.

It is sectional drawing which shows the structure of the DC motor 1 which concerns on this embodiment. It is a disassembled perspective view of the DC motor 1 which mounts the brush holder base 24 which is this embodiment. 4 is an exploded perspective view of the brush holder base 24 and parts mounted on the brush holder base 24. FIG. It is the perspective view of the bush brush holder base 24 seen from one surface in the state in which components were mounted. It is the perspective view of the brush holder base 24 seen from the other surface of the state in which components were mounted. It is a top view of the brush holder base 24 in a state where components are mounted. FIG. 7 is a cross-sectional view of the brush holder base 24 on which the choke coil 16 is mounted as viewed from the direction of the arrow on the plane passing through the line AA in FIG. 6. It is sectional drawing of the brush holder base 24 with which the choke coil 16 was mounted | worn seen from the arrow direction of the plane which passes along BB line | wire of FIG.

  Hereinafter, a brush holder structure according to an embodiment of the present invention will be described with reference to the drawings.

  FIG. 1 is a cross-sectional view showing the structure of a DC motor 1 according to this embodiment. FIG. 2 is an exploded perspective view of the DC motor 1 equipped with the brush holder according to the present embodiment.

  The yoke 2 forms a magnetic circuit while also serving as a motor case. The plurality of magnets 3 are attached to the inner surface of the yoke 2. The armature 4 is accommodated inside the magnet 3 via an inner peripheral surface of the magnet 3 and an arbitrary gap.

  The shaft 5 is provided at the radial center of the armature 4. The shaft 5 is rotatably supported by the yoke 2 and the bracket 7 via the bearing 6 and the bearing 20. The armature core 8 and the commutator 9 are fixed to the shaft 5.

  The plurality of slots 10 are formed in the outer circumferential portion of the armature core 8 in the circumferential direction. The armature coil 11 is wound between the plurality of slots 10.

  The commutator 9 is formed in a cylindrical shape by an insulating material such as resin, and includes a plurality of commutator pieces 12 made of a conductive material on the outer periphery. The armature coil 11 is electrically joined to a part of the commutator piece 12.

  The pair of brushes 14 shown in FIG. 2 supplies power to the commutator piece 12. The brush 14 is pushed out by a spring 15. The choke coil 16 removes electromagnetic noise. The brush holder 13 is housed inside the yoke 2 and mounts the brush 14, the spring 15, and the choke coil 16.

  The brush 14 is electrically connected to the external power supply terminal 26. Further, the brush 14 is brought into sliding contact with the outer peripheral surface of the commutator piece 12 by the pressing force of the spring 15. As a result, power is supplied to the armature coil 11 via the commutator piece 12.

  FIG. 3 is an exploded perspective view of the brush holder base 24 and parts mounted on the brush holder base 24. FIG. 4 is a perspective view of the brush holder base 24 as viewed from one surface in a state where the components are mounted. FIG. 5 is a perspective view of the brush holder base 24 as seen from the other surface in a state where components are mounted. FIG. 6 is a top view of the brush holder base 24 with components mounted thereon.

  The brush holder base 24 is formed in a substantially circular shape by an insulating material such as resin. The brush box 28 holds the brush 14. The spring holder 29 holds the spring 15. In the brush holder 13, the brush box 28 and the spring holder 29 are formed on the brush holder base 24 by a method such as integral molding or assembly by separate parts.

  The brush 14 and the spring 15 are each disposed on the brush holder base 24. The choke coil 16 is installed on the brush 14 mounting surface of the brush holder base 24.

  The power supply terminal 18 is connected to the choke coil 16 and fixed inside the brush holder base 24 by a method such as insert molding. The welding terminal 23 shown in FIG. 4 facilitates the mounting of the choke coil 16 and is electrically connected to the pigtail wire 25. The welding terminal 23 is installed in the brush holder base 24 by a method such as caulking in a through hole 36 formed in the brush holder base 24 shown in FIG.

  Openings 31 shown in FIG. 5 are formed on both surfaces of the brush holder base 24 so as to penetrate the attachment surface of the choke coil 16 of the brush holder base 24 and the back surface thereof. A part of the power supply terminal 18 is exposed through the opening 31 to the mounting surface of the choke coil 16 and the back surface thereof.

  In the present embodiment, the power supply terminal 18 and the external supply terminal 26 provided in the brush holder base 24 are integrally formed. However, the power supply terminal 18 and the external supply terminal 26 are formed as separate parts by joining or the like. Also good. Further, the welding terminal 23 may be fixed to the brush holder base 24 by an insert.

  The choke coil 16 has one end connected to the power supply terminal 18 and the other end connected to the welding terminal 23. As a result, the power supply terminal 18 and the brush 14 are electrically connected via the choke coil 16. The armature coil 16 is fed with power through a commutator piece 12 that is in sliding contact with the brush 14. Note that the end of the choke coil 16 and the pigtail wire 25 may be directly connected by a method such as joining without using the welding terminal 23.

  The substantially cylindrical cap 22 covers the choke coil 16. Thereby, the choke coil 16 and the pigtail wire 25 are separated from each other, the contact with the pigtail wire 25 is prevented, and the adhesion of the brush wear powder to the choke coil 16 is prevented, thereby ensuring insulation.

  The cap 22 is fitted to the brush holder base 24 and fixed by a method such as heat caulking, but a snap fit may be formed at the fitting portion of the brush holder base 24 and the cap 22 may be fixed by the snap fit.

  7 is a cross-sectional view of the brush holder base 24 on which the choke coil 16 is mounted as viewed from the direction of the arrow on the plane passing through the line AA in FIG. 8 is a cross-sectional view of the brush holder base 24 on which the choke coil 16 is mounted as viewed from the direction of the arrow on the plane passing through the BB line of FIG.

  The ferrite core 30 is installed at the center of the choke coil 16. A cap 22 formed in an approximately cylindrical shape with an insulating material such as resin is attached to the outer periphery of the choke coil 16. As shown in FIG. 7, the outer peripheral portion of the choke coil 16 is held by a protrusion 34 formed on the inner peripheral surface of the cap 22.

  Between the cap 22 and the crimped portion formed on the brush holder base 24, the resin of the brush holder base 24 is deformed into a tapered portion 35 provided on the cap 22 by a method such as heat caulking. Tighten. In other words, when the brush holder base 24 is viewed from the direction of the arrow C shown in FIG. 8 (the brush holder base 24 and the direction perpendicular to the mounting surface of the choke coil 16), the brush holder base 24 is The taper part 35 which overlaps with the part is formed. Thereby, the cap 22 is prevented from coming off and the cap 22 is firmly fixed to the brush holder base 24.

  Further, as shown in FIG. 7, the cap 22 is formed by a caulking punch 32 having a convex shape from the upper surface of the cap 22 when performing heat caulking, so that the upper surface of the cap 22 faces the ferrite core 30. The deformed portion 33 is formed, and the gap between the cap 22 and the ferrite core 30 is eliminated, and the ferrite core 30 is fixed.

  Conventionally, as a fixing method of the ferrite core 30 and the choke coil 16, a fixing method using an adhesive is generally used. However, in the present embodiment, it is possible to fix without using an adhesive. The choke coil 16 and the ferrite core 30 can be fixed without the agent application operation.

  In addition, for example, a DC motor mounted on a vehicle engine unit is exposed to a high temperature environment, which may exceed the heat resistance temperature of the adhesive and lose the adhesive fixing function. Can do. In order to ensure the insulation between the choke coil 16 and the pigtail wire 25, there is a method of covering the outer periphery of the choke coil 16 with, for example, an adhesive or an insulating tape. There is. In this embodiment, the workability is easy and the uniform quality can be ensured by simply attaching the cap 22.

  As described above, by using the cap 22 for the purpose of ensuring insulation between the pigtail wire 25 and the choke coil 16, it is possible to provide the DC motor 1 having high reliability while being a small brush holder.

DESCRIPTION OF SYMBOLS 1 ... DC motor, 2 ... Yoke, 3 ... Magnet, 4 ... Armature, 5 ... Shaft, 6 ... Bearing, 7 ... Bracket, 8 ... Armature core, 9 ... Commutator, 10 ... Slot, 11 ... Armature coil, 12 ... Commutator piece, 13 ... Brush holder, 14 ... Brush, 15 ... Spring, 16 ... Choke coil, 18 ... Feeding terminal, 20 ... Bearing, 22 ... Cap, 23 ... Welding terminal, 24 ... Brush holder base, 25 ... Pigtail wire , 26 ... external power supply terminal, 28 ... brush box, 29 ... spring holder, 30 ... ferrite core, 31 ... opening, 32 ... caulking punch, 33 ... deformation part, 34 ... projection part, 35 ... taper part

Claims (3)

A brush that feeds the commutator;
Wiring connected to the brush;
A cylindrical choke coil connected to the wiring;
A base formed of an insulating material on which the brush and the choke coil are mounted;
A cap formed of an insulating material covering an outer peripheral portion of the choke coil mounted in a standing state on the mounting surface of the base ,
When viewed from the vertical direction of the mounting surface of the choke coil of the base,
The base is a direct current motor in which a tapered portion that overlaps with a part of the cap is formed at a tip of a protruding portion formed by standing from a mounting surface of the base . The DC motor according to claim 1,
The cap is a DC motor in which a protrusion for pressing the choke coil against the base is provided on an inner peripheral portion of the cap. In the DC motor according to claim 1 or 2,
A core provided on the choke coil;
The cap is a DC motor in which a protrusion for pressing the core against the base is provided on an inner peripheral portion of the cap.

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