JP2002345213A - Pair of 90° opening angle brush - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a means preventing a defect that in a flat motor, in brushes taking a pair of truncated chevron shaped-arrangement into slide contact at an opening angle of center angle 90 deg. relating to a disk-shaped commutator of an armature corresponding to a fixed field magnet of four-pole hollow disk shape, a mutually forward/reverse direction is taken relating to a rotational direction, when the reverse direction is taken relating to the rotational direction, resistance of the brush is increased, to quicken abrasion, shorten the life, or at passing a slit, generate vibration and spark, and generate electric noise. SOLUTION: The arrangement of a pair of brushes is changed from a truncated chevron shape into a superposition type taking the same direction, an opening angle of center angle 90 deg. is taken relating to a disc-shaped commutator, the same direction to a forward direction is taken relating to rotation, the root of the brush is made small for avoiding superposition with a circular arc shape in a sliding tip end of the brush for taking the forward direction, a means for ensuring a clearance for avoiding a contact short-circuiting is adopted.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pair of 90.degree. Open angle brushes which contact a disc-shaped commutator of an armature with an opening angle of 90.degree. In a small flat motor.

In a small flat motor, three coils are arranged uniformly in a circular shape, or three or two or one coil is provided on one side, mainly corresponding to a four-pole hollow disk-shaped fixed field magnet. Some commutators have six or four segments, and some have eight, with a pair of brushes being centered. An open angle arrangement of 90 ° is adopted.

[0003]

2. Description of the Related Art A brush in sliding contact with a disk-shaped commutator is arranged in a pair of U-shapes in order to obtain an opening angle of a central angle of 90 °.
No. 2000-152585.

[0004]

SUMMARY OF THE INVENTION Conventionally, Japanese Patent Publication No. 3039857 and Japanese Patent Laid-Open Publication No. 2000-15
Each pair of brushes described in 2585 has a pair of C-shaped arrangements in order to take an opening angle of 90 ° central angle. Therefore, the pair takes forward and reverse directions with respect to the rotation direction. If the direction opposite to the rotating direction is taken, the resistance of the brush will increase, the wear will be accelerated, the life will be shortened, and when passing through the slit of the commutator, there will be a drawback that vibration and sparks are generated and electrical noise is generated, which prevents this. It is necessary to provide means for doing so.

[0005]

SUMMARY OF THE INVENTION The present invention has been made to achieve the above-mentioned object. In order to make a brush taking a direction opposite to rotation take a forward direction, a pair of brushes is used. A superimposed arrangement that takes the same direction from the letter-shaped arrangement is adopted, and a measure is taken to secure a gap in order to avoid contact short-circuit between the brushes due to the overlap.

For this reason, a pair of brushes are arranged so as to overlap each other so as to have an opening angle of a central angle of 90 ° with respect to the disk-shaped commutator and to be in the same direction in the forward direction with respect to the rotation. The arc shape at the sliding tip of the brush was made small to take a forward direction, and a gap was secured.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described with reference to the drawings based on embodiments. FIG.
No. 039857 and FIG.
In the embodiment according to 52585, the armature 20 comprises one central coil 1, a disc-shaped commutator 10 and a central bearing 9, the commutator 10 having four segments a. The slit b of the commutator 10 of FIG. 2 separated by the slits b has a protrusion c at the center. FIG. 3 shows a four-pole hollow disk-shaped field magnet 15 facing the armature 20.
A pair of brushes 4 having a central angle of 90 ° inside,
5 and 4 for the rotation direction 16 around the center 11
Indicates a forward direction and 5 indicates a reverse direction.

Here, when actually operated, the slits b, b of the disc-shaped commutator 10 in FIG.
As shown in (a), when the brush tips 6, 6 come in contact with the same segment a, a short-circuit occurs momentarily during rotation, sparks are generated, electric noise is generated, and the brush is worn. FIG. 2 shows a projection c provided at the center of the slit b. As shown in FIG. 4B, an instantaneous short circuit can be avoided, but a sharp impact occurs at the brush tip 6, and the brush 4 in the forward direction is free to escape. Although the impact occurs slightly, the reverse brush 5 generates vibration, electric noise, and abrasion due to a strong impact, and the life is reduced. Therefore, as shown in FIG. However, the mass of the tip is increased, and vibration is caused to easily cause electric noise.

In addition to the four segments a of the commutator 10 shown in FIGS. 1 and 2, those having six or more conventional segments a also have a four-pole hollow disk-shaped field facing the armature 20 in FIG. The magnet 15 has a pair of brushes 4 and 5 having an opening angle of a central angle of 90 ° inside the magnet 15, and 4 is a forward direction and 5 is a reverse direction with respect to a rotation direction 16 about the center 11 as an axis. Is also adaptable. As an example of this, FIG. 5 shows the number of segments of the uniform three-coil commutator 10, FIG. 6 shows the number of segments of the unevenly distributed three-coil commutator 10, and FIG. FIG. 8 shows an unevenly distributed two-coil commutator 10 having eight segments. In any case, there is no short-circuit between the brushes 4 and 5 and the segment a, and there is no protrusion c of the slit b where a strong impact is generated. It is larger than the brush 4 in the direction, indicating a decrease in life. In each figure, a pair of brushes each having an opening angle of 90 ° at each center are indicated by phantom lines.

FIG. 9 shows an embodiment of the present invention, in which a pair of brushes are arranged in an overlapping manner so as to have the same forward direction with respect to the rotational direction, and a gap is secured to avoid contact and short circuit between the brushes due to the overlapping. The brush 8 in the forward direction of an arc of about 1/4 circle with respect to the rotation direction 16 about the center 11 as an axis.
A pair of superimposed brushes are formed by superimposing a forward brush 7 having an arc of approximately 1/4 circle. A brush root 13 is an arc-shaped gap with respect to the brush root 12 as shown in the figure. 14 to ensure a fundamental gap between the brushes. Also, as shown in FIG. 3A, the arc shapes 6, 6 at the tip of the brush are small because the brush is in the forward direction, and the gap 17 between the brushes is secured.

A brush having a superposition arrangement in the forward direction in the same direction as the rotation direction 16 is replaced with a disk-shaped commutator 10 having four segments a and a projection c provided at the center of a slit b. FIG. 10 shows an example of an adaptation. In this case, as shown in FIG. 10B, the brushes 7 and 8 are in the forward direction with respect to the rotation direction and are easy to escape from the projection c. The shape is small and the generation of vibration is small.

[0012]

As described above, in the flat-type motor, the pair of the armature disc-shaped commutators corresponding to the four-pole hollow disc-shaped field magnets are slid in contact with the central angle of 90 ° with an open angle. In the brush of the above, the arc shape at the tip can also be reduced by overlapping and leaving a gap that does not contact each other in the same direction, and the impact generated by the rotation of the tip of the brush and the slit of the commutator and the projection in the slit Was able to alleviate the problem by escaping, preventing the reduction of life due to vibration, generation of electrical noise, and wear.

[Brief description of the drawings]

FIG. 1 shows an embodiment of a conventional one-coil four-segment commutator.

FIG. 2 shows a conventional one-coil, four-segment, embodiment in which a slit has protrusions.

FIG. 3 is a layout diagram of a conventional field magnet and a C-shaped brush.

FIG. 4 (a) Contact diagram between brush and slit of commutator

FIG. 4 (b) A contact diagram of a brush and a protrusion in a slit of a commutator.

FIG. 5 is an example of a conventional equivalent three-coil six-segment commutator.

FIG. 6 shows an embodiment of a conventional unevenly distributed three-coil six-segment commutator.

FIG. 7 shows an embodiment of a conventional unevenly distributed two-coil six-segment commutator.

FIG. 8 is an embodiment of a conventional unevenly distributed 2-coil 8-segment commutator.

FIG. 9 shows an embodiment of a four-pole field magnet having a pair of brushes of the superposition type according to the present invention.

FIG. 10 is an application example of a pair of brushes of a superposition type according to the present invention; (b) a contact diagram between a protrusion in a slit of a commutator and a brush;

[Explanation of symbols]

REFERENCE SIGNS LIST 1 coil 11 axis 2 coil 12 root of superimposed brush 3 coil 13 root of superimposed brush 4 forward brush 14 gap 5 reverse brush 15 magnet 6 brush tip 16 rotating direction 61 brush tip 17 brush gap 7 superposition brush 20 armature 8 Superposition brush a Segment 9 Bearing b Slit 10 Commutator c Projection

Claims (1)

[Claims] In a flat type motor, a pair of brushes which slide in contact with a disk-shaped commutator of an armature corresponding to a quadrupole hollow disk-shaped fixed field magnet at an opening angle of a central angle of 90 ° are provided. A pair of 90 ° open-angle brushes, which are arranged so as to overlap with each other with a gap that does not contact each other in the directions.