JPS6111981Y2 - - Google Patents

Description

[Detailed description of the invention] The present invention relates to a small DC motor having a cup-shaped coreless armature, in which a commutator is provided on the inner surface of the bottom of the cup, and a brush holder is mounted on a stand that holds a magnet placed inside the cup. The object of the present invention is to provide a small, thin DC motor with the following features.

As shown in Fig. 1, a conventional small DC motor with a non-ferrous core armature has a cup type non-ferrous core armature by fixing the armature winding 1, commutator 2, and shaft 3 with a fixing plate 4. A yoke 6 attached to a frame 5 is disposed on the outer periphery of the armature, and a magnet 8 attached to a magnet holder 7 made of an electrically insulating material is attached to the yoke 6 on the inner periphery of the armature. They are placed facing each other. Bearings 9 and 9' for rotatably supporting the armature shaft 3 are attached to the center of the magnet holder 7, and the frame 5 is attached to the outer periphery of the magnet holder 7. cover 1 attached to frame 5
0 is provided with a terminal plate 12 via an insulating plate 11, and a brush 14 is attached to the terminal plate 12 so as to be in sliding contact with the segment portion 13 of the commutator 2, which has a sliding contact portion on the outside of the bottom of the cup. ing. Note 1
5 is a thrust washer, and 16 is an E-shaped washer for preventing vertical movement of the shaft 3.

In the conventional motor mentioned above, the distance from the outside of the lower part of the motor (cover) to the sliding part of the commutator is short, so the sliding sound of the motor leaks to the outside, and the microphone built into the motor cannot be heard in a set such as a cassette. There were problems such as echoes being recorded by the built-in microphone, and the sliding part occupied a large proportion of the height of the motor, hindering the development of thinner sets. In addition, in order to make the motor thinner, motors with so-called flat coreless armatures have been implemented in which the armature windings are arranged in a flat plate shape and the magnetic field is parallel to the axis, but the outer diameter becomes larger. There were problems such as armature imbalance and the number of man-hours involved in arranging the armature windings.

The present invention solves all of the above-mentioned conventional problems, and an embodiment thereof will be described with reference to FIG. Note that the same numbers are used for the same parts as in the conventional configuration described above, and the explanation thereof will be omitted. In the figure, the difference from the conventional configuration is that a commutator segment 17 is provided on the inner surface of the bottom of the armature cup having the armature winding 1,
The commutator segment 17 is held on the shaft 3 by commutator molding resin 18, and the armature winding 1 is
The armature is configured by being held on the commutator mold resin 18 by a fixing plate 19. On the other hand, the magnet holder 20 that holds the frame 5, the magnet 8, and the bearings 9, 9' is provided with two brush holder holes 21 at positions facing the commutator segment 17. 22, coil spring 23, conductive holder cap 24
has been established. Note that 25 is a commutator riser to which the lead wire of the armature winding 1 is connected.

With the above construction, the armature is rotated by supplying power to the brush holder cap 24.

As described above, the present invention provides a commutator on the inner surface of the bottom of the cup-shaped armature, and also provides two brush holder holes in the magnet holder facing the commutator, and inserts the brush into the brush holder holes. Since it is held by a coil spring, it has the following effects.

Since the brush sliding contact area is in the center of the motor, sliding noise does not leak outside the motor.

Since the brush holder hole is provided between the magnet and the bearing, no space is required for the brush holder, the height of the motor can be reduced, and there is no need to increase the outer diameter, resulting in high volumetric efficiency.

It is easy to use a coil spring to push the brush, which improves the followability of the brush and is advantageous in reducing sliding noise, brush and commutator wear, etc.

It is possible to hold the motor, connect it to a power source, transmit output, etc. only on the top of the motor, making maintenance and inspection easy.

[Brief explanation of the drawing]

Figure 1 is a cross-sectional view of a conventional small DC motor, Figure 2
The figure is a sectional view of a small DC motor according to an embodiment of the present invention. 1... Armature winding, 3... Shaft, 6... Yoke, 8... Magnet, 9, 9'... Bearing, 1
7... Commutator segment, 20... Magnet holding base, 21... Brush holder hole, 22... Brush,
23...Coil spring.

Claims (1)

[Scope of utility model registration request] In a small DC motor having a cup-shaped ironless core armature, a magnet provided in the armature, and a yoke provided on the outer periphery of the armature opposite to the magnet, the shaft attached to the armature A pair of brush holder holes are provided in opposing positions centering on the shaft in a magnet holding base that holds the magnet and a bearing that rotatably supports the armature, and the cup bottom of the armature faces the brush holder holes. A small direct current motor comprising a commutator segment provided on the inner surface and a brush energized by a spring so as to be in constant contact with the commutator segment in the brush holder hole.