JPS5845508Y2 - small dc motor - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a small DC motor having a cup-shaped ironless armature.

In a conventional small DC motor with a coreless armature, the armature is constructed by fixing an armature winding 1, a cylindrical commutator 2, and a shaft 3 with a fixing plate 4, as shown in FIG. A frame 6 is provided to hold a yoke 5 that passes magnetic flux around the outer periphery of the child,
On the other hand, a magnet 7 disposed inside the yoke 5 and a magnet holder 9 equipped with an 8° bearing for rotatably holding the armature shaft 3 are provided on the inner periphery of the armature, and is attached to the frame 6. An insulating plate 11 is attached to the bracket 10.
A brush holder 12 is provided through the brush holder 12, and the brush 13 held in the brush holder 12 is provided so as to be in sliding contact with the segment portion 14 of the commutator 2 having a cylindrical sliding portion.

However, with the above configuration, the brush 13 and the brush holder 12 must be made of the same ribbon-like material, and there is not much space for the brush holder, and it is very difficult to attach anti-vibration rubber, etc. There are problems such as sliding noise leaking to the outside of the motor, reverberating within the set such as a micro cassette that houses the motor, and being recorded by the built-in microphone.Also, the sliding part makes up a large proportion of the motor height, making the set This hindered the thinning of the product.

In order to make the motor thinner, motors with so-called flat coreless armatures, in which the armature windings are arranged in a flat plate and the magnetic field is set parallel to the axis, have also been put into practical use, but the outer diameter There were problems such as sagging, armature imbalance, and the amount of work required to arrange the armature windings.

The present invention has been devised in view of the above-mentioned drawbacks of the conventional art, and one embodiment of the present invention will be described below with reference to FIG. 2.

The same numbers are used for the same parts as in the conventional structure described above, and the explanation thereof will be omitted.

As shown in the figure, the armature consists of an armature winding 1, a commutator mold 16 to which a flat plate commutator segment 15 is attached, a button and a shaft 3, which are held by a fixing plate 4. A protrusion 18 that protrudes outward is provided at the center of the flakets 17 in a row in the commutator segment 15, and an elastic material 19 made of rubber or the like is provided inside the protrusion 18.
The vicinity of the sliding portion is elastically pressed against this elastic material 19,
A brush 20 is provided so that its tip is in sliding contact with the commutator segment 15, and this brush 20 is attached to the bracket 17 via a brush holder 21.

Hey, 22 is the equipment case.

As is clear from the above configuration, the present invention provides a flat plate commutator at the bottom of the camph type armature, and also has the central part of the bracket provided at the bottom of the motor protrude outward, and a vibration-proofing material is provided within this protruding part. Since the vicinity of the sliding contact portion of the brush that comes into sliding contact with the flat commutator is brought into pressure contact with the vibration isolating material, the following effects are achieved.

(a) Since the chattering of the brush is reduced by the anti-vibration material, the generation of sliding noise is reduced.

(b) Since there is a vibration-proofing material between the sliding sound generating part and the outside, the sliding sound hardly leaks to the outside.

(C) Since a flat plate commutator is used, the motor height σ is low and the volumetric efficiency is high.

(The central protrusion of the bracket allows it to be inserted into the hole in the case, making positioning within the motor set easy.

[Brief explanation of drawings]

FIG. 1 is a sectional view of a conventional small DC motor, and FIG. 2 is a sectional view of a small DC motor according to an embodiment of the present invention. 1... Armature winding, 3... Shaft, 5... Yoke, 6... Frame, 7... Magnet, 15...
・Flat type commutator segment, 17...Bracket, 1
8...Protrusion part, 19...Elastic material, 20...Brush.

Claims (1)

[Scope of utility model registration request] a magnet holder equipped with a bearing that rotatably holds the armature shaft; a magnet fixed to the magnet holder; a frame having one end attached to the magnet holder; a yoke fixed to an inner surface of the frame; a cup-shaped armature winding attached to the shaft and located in the gap between the yoke and the magnet; a bracket covering an end opening of the frame; a flat commutator segment attached to the bottom of the cup of the armature winding; a brush attached to the outer periphery of the bracket via a brush holder, one end of which is in sliding contact with the commutator segment; A protrusion protruding outward is provided at the bottom, a vibration isolating material is provided within the protrusion, and a vibration isolating material is provided on the top of the protrusion so as to press against the vicinity of the sliding contact portion of the brush that is attached to the bracket and slides into contact with the commutator segment. A small DC motor.