JPH09117109A - Cylindrical commutator of compact dc motor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a cylindrical commutator where the strength of a riser part is improved and at the same time the insulation from a coil is made possible by extending one portion of a core member at least to the coil side of the riser part. SOLUTION: In a cylindrical commutator 7, a conductive segment 22 which is divided into a plurality of portions around a core 21 with a cylindrical part consisting of such insulation material as synthetic resin is uniformly arranged and a riser part 23 which projects in the direction of diameter in one piece with the segment 22 is formed. Then, a winding part 24 is formed at the tip of the riser part 23 to connect the terminal of a coil, for example, by binding. Also, an extension part 26 is arranged in one piece at the riser part 23 by extending one portion of the core member 21 at the coil side, thus preventing the terminal part 24 from being deformed without increasing the number of parts, insulating from the coil, and improving strength.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cylindrical commutator for a small direct current motor, and more particularly to improvement of a riser portion of the cylindrical commutator.

[0002]

2. Description of the Related Art FIG. 4 is a sectional view of a main part of a conventional small direct current motor, and FIG. 5 shows a conventional cylindrical commutator thereof, (a) is a plan view and (b) is a sectional view. is there. In FIG. 4, reference numeral 31 denotes a case having a bottomed cylindrical shape having an opening at one end, and a cylindrical magnet 32 is provided on the inner surface of the case 31. Case 3
A rotor 34 rotatably supported by a bearing 36 is disposed in the magnet 32 by a core 34 fixed to a shaft 33 and a coil 35 formed in the core 34 in the magnet 1. There is. This rotor S has a shaft 3
A cylindrical commutator 37 inserted in the No. 3 is provided.

A bracket 38 made of, for example, synthetic resin is fitted in the opening of the case 31, and a bearing 39 for rotatably supporting the shaft 33 together with the bearing 36 and a cylindrical commutator are fitted in the bracket 38. A pair of brushes 40 that are in sliding contact with 37 are provided.

A conventionally used cylindrical commutator 37 is as shown in FIG. 5, in which 41 is a cylindrical core made of synthetic resin and a plurality of cores 41 are provided around the core 41. Segments 42 made of noble metal divided into (three in the figure) are arranged. Further, a riser portion 43 is formed integrally with the segment 42 in the radial direction, and a winding portion 44 for connecting the end of the coil 35 is formed at the tip portion of the riser portion 43. In addition, 4
Reference numeral 5 is a washer for holding the segment portion having the above-mentioned configuration on the core 41.

[0005]

However, in the above structure, the riser portion is exposed without being particularly protected, so that various problems as shown in FIG. 6 occur. Here, FIG. 6A is a diagram showing a relationship between the cylindrical commutator and the coil, and FIG. 6B is a diagram showing a state when the end of the coil is soldered to the cylindrical commutator.

First, as can be seen from (a), the riser portion 43 of the cylindrical commutator 37 and the coil 35 are superposed, and in this state, the flattened type, the number of turns of the coil 35 increases. It becomes more prominent. In this case, the coil 35 may come into contact with the riser portion 43 to cause a rare short circuit, or the solder may flow and come into contact when soldering the coil end.

Further, in (b), the cylindrical commutator 3 is used.
When the coil end is soldered to the winding portion 44 of 7 and the riser portion 43 is pressed in the Y direction, the segment 42 integrally formed with the riser portion 43 is rotated by the momentum.
It deforms in the direction. Therefore, the contact with the brush 40 becomes very unstable.

Therefore, the present invention provides a cylindrical commutator for a small direct current motor, which solves the above problems and improves the strength by improving the riser portion, and at the same time, enables insulation from the coil. To do.

[0009]

SUMMARY OF THE INVENTION A cylindrical commutator for a small direct current motor according to the present invention comprises a cylindrical core member made of an insulating material, and a plurality of divided segments arranged around the cylindrical core member. In a cylindrical commutator of a small direct current motor which is projected to a part, a part of the core member is extended to at least the coil side of the riser portion. It is preferable that the extension portion is provided just before the coil winding portion of the riser portion.

[0010]

If a part of the core member is extended in the radial direction and this extended portion is arranged at least on the coil side of the riser portion, the riser portion can be insulated from the coil. The strength can be improved.

[0011]

[First Embodiment] FIG. 1 is a sectional view of a main part of a small direct current motor according to a first embodiment of the present invention, and FIG. 2 is a plan view (a) showing the cylindrical commutator in FIG.
(B) It is sectional drawing. In FIG. 1, 1 is a case having an opening at one end and formed in a cylindrical shape with a bottom, and an annular magnet 2 is arranged on the inner surface of the case 1. Further, in the case 1, a rotor S having a core 3 fixed to a shaft 3 and a plurality of coils 5 formed on the core 4 is provided on the output side of the shaft 3 through a gap in a magnet 2. It is rotatably supported by a bearing 6 arranged in the case 1.

A cylindrical commutator 7 is attached to the shaft 3 not on the output side but on the opposite side, and the commutator 7 has a structure as shown in FIG. On the other hand, a bracket 8 made of synthetic resin or the like is fitted in the opening of the case 1, and the bracket 8 is provided with a bearing 9 for rotatably supporting the other end of the shaft which is not the output side. Further, a pair of elastic brushes 10 are attached, and the brushes 10 are brought into sliding contact with the cylindrical commutator 7.

Now, the cylindrical commutator of the present invention will be described with reference to FIG. That is, in the figure, a plurality of cylindrical commutators 7 are provided around the core 21 having a tubular portion made of an insulating material such as synthetic resin (in the figure, 3
Conductive segments 22 divided into individual pieces are evenly arranged, and a riser portion 23 projecting in the radial direction is integrally formed with the segment 22. The riser portion 23 has a coil 5 at the tip thereof. A winding part 24 is formed for connecting the terminals of the device by twisting or the like. In addition, 25 is a ring washer for pressing which prevents these conductive members from coming off.

An extension portion 26 is integrally arranged in the riser portion 23 by extending a part of the core member 21 in the radial direction on the coil side thereof. By doing so, the terminal portion 24 can be provided without increasing the number of parts.
Can be prevented from being deformed, and its strength can be significantly improved. Moreover, the insulation from the coil can be easily achieved, and the reliability is also improved.

[0015]

[Second Embodiment] FIG. 3 is a plan view of a cylindrical commutator according to a second embodiment of the present invention. As shown in FIG. 3, the extending portion 26 of the core member 21 is formed not only in the riser portion 23 but also in a disc shape. According to this structure, it is relatively easy to create a mold, and the dimensions of parts can be easily managed.

In each of the above embodiments, the assembly type cylindrical commutator is described in detail, but it is needless to say that the present invention can be applied to a mold type commutator by integrally molding a core member and a segment portion. Nor. Further, in the present invention, if it is extended to at least the riser portion on the coil side, the other shapes can be variously modified in addition to the above embodiments.

[0017]

As described above, according to the present invention, if a part of the core member is extended to at least the coil side of the riser portion, the riser portion is insulated from the coil and its strength is improved. Therefore, the reliability is improved without being deformed even when the terminal portion is pressed. Moreover, since the horizontal portion can be made large, the dimensional stability of the riser portion can be improved and the riser portion can be easily assembled.

[Brief description of the drawings]

FIG. 1 is a sectional view of an essential part of a small DC motor according to a first embodiment of the present invention.

FIG. 2 shows the cylindrical commutator in FIG.
It is a (a) top view and a (b) sectional view.

FIG. 3 is a plan view of a cylindrical commutator according to a second embodiment of the present invention.

FIG. 4 is a cross-sectional view of a main part of a conventional small DC motor.

FIG. 5 shows a conventional cylindrical commutator,
(A) is a plan view and (b) is a sectional view.

FIG. 6A is a diagram showing a relationship between a cylindrical commutator and a coil, and FIG. 6B is a diagram showing a state when the end of the coil is soldered to the cylindrical commutator.

[Explanation of symbols]

 7: Cylindrical commutator 21: Core 22: Segment 23: Riser part 24: Terminal part 26: Extension part

Claims (2)

[Claims] 1. A cylindrical commutator for a small direct current motor, wherein a plurality of divided segments are arranged around a cylindrical core member made of an insulating material, and a riser portion of this segment is projected in a radial direction. A cylindrical commutator for a small DC motor, wherein a part of the member is extended to at least the coil side of the riser portion. 2. The cylindrical commutator for a small DC motor according to claim 1, wherein the extended portion is provided up to immediately before a coil winding portion of the riser portion.