JPS5828463Y2 - small dc motor - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a small DC motor suitable for driving a tape recorder, etc., and particularly to a structure for holding a winding portion of a rotor.

In this type of electric motor, as shown in Fig. 1, a ring-shaped permanent magnet 2 magnetized in the axial direction is fixed in a case 1 consisting of an upper cylindrical body 1A and a bottom plate 1B made of a magnetic material such as an iron plate. An annular axial gap is formed by the upper surface of the permanent magnet 2, the top of the upper cylindrical body, the valve plate, and the valve plate.

Further, a disc-shaped rotor 3 configured by integrally molding an armature winding 4 with a synthetic resin 5 is fixed to a rotating shaft 7 rotatably supported in the case 1 via a bearing 6. , and the armature winding 4 is disposed within the annular axial gap.

In addition to the rotor 3, a commutator 8 is fixed to the rotating shaft 7, and a brush (not shown) is pressed into contact with the commutator 8.

In such an axial gap type electric motor, the time required for the process of integrally molding the armature winding 4 with the synthetic resin 5 is generally longer than other processes, and it is extremely difficult to shorten the time required for the process. Moreover, it is also very difficult to accurately position and fix the armature winding 4 by molding.

Furthermore, in an axial gap type electric motor using such a rotor 3, the thickness of the rotor 3 in the axial direction is equal to that of the armature winding 4.
is the sum of the width of the case 1 and the thickness of the coating of the synthetic resin 5, and the distance between the case 1 and the permanent magnet 2 becomes longer due to the thickness of the coating of the synthetic resin 5. In addition to the effective magnetic flux that interlinks with the armature winding 4 of the rotor 3 and reaches the case, as shown by the arrow φ2 from the permanent magnet 2, it interlinks with the armature winding 4 of the rotor 3. This has the disadvantage that leakage magnetic flux directly enters the case 1 in the radial direction without doing so, and the magnetic flux generated by the permanent magnet 2 cannot be fully utilized.

The purpose of the present invention is to eliminate the above-mentioned drawbacks, to position and fix the armature winding 4 with high accuracy in a short time, and to increase the amount of effective magnetic flux interlinking with the rotor winding, thereby increasing its output. The object of the present invention is to provide a small-sized DC motor that can increase the amount of power.

To achieve this objective, the present invention is characterized in that the rotor windings are fixed to a plate-shaped holder made of a magnetic material.

Hereinafter, one embodiment of the present invention will be described with reference to FIGS. 2 and 3.

In FIGS. 2 and 3, the same reference numerals as in FIG. 1 indicate the same or equivalent parts.

The structure is similar to that of a conventional electric motor, except that the armature winding 4 of the disc-shaped rotor 3 is fixed to a plate-shaped holder 9 made of a magnetic material having magnetic permeability equal to or higher than that of the case 1. .

FIG. 3a shows a state in which the winding 4 is fixed to the holder 9.

Fixing pieces 9a and 9b are formed in this holder 8 by cutting, and the fixing piece 9a provided on this holder 9 is bent while pressing the inner part 84a of the winding 4 so as to pull the winding 4 in the axial direction. The blade fixing pieces 9b are bent between the windings 4 so as to push and spread the thresholds of the windings 4, and the holder 9 fixes the windings 4 using these two types of fixing pieces 9a and 9b.

According to the present embodiment described above, the winding 4 is fixed to the holder 9 simply by mechanically bending the fixing pieces 9a and 9b of the holder 9, so that the winding 4 can be fixed in a shorter time than the manufacturing process, and
Can be positioned and fixed with high precision.

Furthermore, since a plate-shaped holder 9 having a magnetic permeability equal to or higher than that of the case 1 is provided in the axial gap facing the permanent magnet 2, the magnetic resistance of the magnetic path against the effective magnetic flux passing through the axial gap is reduced. The leakage magnetic flux generated from the outer periphery of the armature winding 4 is effectively guided to the holder 9 having high magnetic permeability.

As explained above, according to the present invention, the armature winding is mechanically fixed to the holder made of a magnetic material having magnetic permeability equal to or higher than that of the case using a fixing piece, so that the winding can be quickly and easily fixed. It has great practical effects because it can be accurately positioned and fixed, and the amount of effective magnetic flux interlinked with the windings can be increased to increase the motor output.

[Brief explanation of the drawing]

Figure 1 is a vertical cross-sectional view of a conventional small DC motor;
The figure is a longitudinal sectional view of a small DC motor showing one embodiment of the present invention. FIG. 3 is a diagram showing the state in which the winding wire 4 of the present invention is attached to the holder 9, the holder 9, and the winding wire 4. 1... Case, 2... Ring-shaped permanent magnet, 3... Rotor, 4... Armature winding, 9 Holder.

Claims (1)

[Scope of utility model registration request] A small DC motor in which the rotor windings are placed in the axial gap formed between the permanent magnet and the case, which is equipped with a plate-shaped holder made of a magnetic material with magnetic permeability equal to or higher than that of the case. A small direct current motor, characterized in that the holder is formed by bending a fixing piece for fixing to the winding part.