JPH0130874Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a small motor, and particularly to a structure for positioning a bracket with respect to a case.

FIG. 1 is an exploded perspective view of essential parts of a conventional small motor. A rotor 5, a yoke plate 6, a vibration isolating rubber 7, and a bracket 8 are sequentially inserted into a cup-shaped case 4 having a cylindrical peripheral wall 1 and a bottom wall 3 having a through hole 2 in the center. .

The shaft 9 of the rotor 5 is inserted into the through hole 2 of the case 4. A permanent magnet 10 is attached to the surface of the yoke plate 6 facing the rotor 5, and three protrusions 11 are integrally formed on the outer periphery of the yoke plate 6 at predetermined intervals in the circumferential direction. on the other hand,
Vertical groove-shaped locking recesses 12 are formed in the peripheral wall portion 1 of the case 4 at locations corresponding to the protrusions 11 of the yoke plate 6, respectively. Therefore, by fitting each protrusion 11 into the locking recess 12, the yoke plate 6 is positioned with respect to the case 4 in the axial direction and the circumferential direction. A brush holder 14 holding a plurality of brushes 13 is attached to the bracket 8, and the brushes 13 are in sliding contact with the rotor 5.

A stepped portion 15 is previously formed along the circumferential direction at the position where the bracket 8 is placed on the inner circumferential surface of the case 4. By locking the outer circumferential portion of the bracket 8 to this stepped portion 15, the bracket 8 can be fixed. 8 is case 4
It has a structure that allows it to be positioned against.

By the way, in this conventional small motor, Case 4
It is necessary to form a step 15 on the inner peripheral surface of the case 4, and since the step 15 simply extends in the circumferential direction, it is necessary to position the bracket 8 in the circumferential direction with respect to the case 4 by another means. It was hot. As a result, the number of parts increases, work efficiency is poor, and costs are high.

An object of the present invention is to provide a small motor that eliminates the drawbacks of the prior art, reduces the number of parts, improves work efficiency, and reduces costs.

To achieve this objective, the present invention provides a small motor in which a rotor, a yoke plate holding a permanent magnet, and a bracket having a brush holder are sequentially inserted into a case having a side wall.
at least one protrusion on the outer periphery of the yoke plate,
Protrusions wider than the protrusions of the yoke plate are provided on the outer periphery of the bracket, and at least one narrow groove part having a groove width approximately the same as the protrusion of the yoke plate is provided on the side wall of the case. , at least one wide groove having a groove width of approximately the same size as the protrusion of the bracket provided above the narrow groove, and the protrusion of the yoke plate is placed in the narrow groove of the case,
The yoke plate and the bracket are positioned relative to the case in the axial and circumferential directions by fitting the protrusions of the bracket into the wide grooves.

Next, an embodiment of the present invention will be described with reference to FIGS. 2 to 4.

Fig. 2 is an exploded perspective view of essential parts of a small motor according to an embodiment of the present invention, Fig. 3 is a perspective view of the small motor after assembly is completed, and Fig. 4 is a diagram for explaining the machining of the case of the small motor. It is a diagram.

As shown in FIG. 2, the rotor 5, the yoke plate 6 to which the permanent magnet 10 is attached, the vibration isolating rubber 7, and the bracket 8 to which the brush holder 14 is attached are sequentially inserted into the case 4 as in the conventional case.

Three protrusions 11 are integrally formed on the outer periphery of the yoke plate 6 at predetermined intervals, and a bracket 8
Three protrusions 15, which are slightly wider than the protrusions 11, are integrally formed on the outer periphery of the yoke plate 6 at positions corresponding to the protrusions 11 of the yoke plate 6.

On the other hand, on the peripheral wall 1 near the opening of the case 4, there are three narrow grooves 16 along the circumferential direction, each having a groove width approximately the same as the protrusion 11 of the yoke plate 6. Above is the protrusion 15 of the bracket 8.
Wide groove portions 17 having substantially the same groove width are provided respectively. Therefore, as shown in Figure 3,
When sequentially inserting the rotor 5, yoke plate 6, anti-vibration rubber 7, bracket 8, etc. into the case 4, insert the protrusion 11 of the yoke plate 6 into the narrow groove 16 of the case 4, and insert the protrusion 14 of the bracket 8 into the wide groove. By inserting them into the grooves 17, the yoke plate 6 and the bracket 8 can be simultaneously positioned with respect to the case 4 in the axial direction and the circumferential direction.

4 and 5 show a wide groove 1 in the case 4.
6 is a diagram for explaining a process of forming a wide groove portion 6 and a wide groove portion 17 at the same time. That is, a split mold 18 is placed in the case 4 in contact with the peripheral wall 1 of the case 4, and a wide groove 17 is formed between the split molds 18.
Three intervals 19 are formed which are slightly larger than the groove width. A punch 20 is installed on the outside of the case 4 at a position corresponding to the interval 19, and the punch 20 has a T-shaped front view as shown in FIG. It is composed of a narrow lower end portion 21 and a wide upper end portion 22 for forming the wide groove portion 17. This punch 20
By driving the grooves toward the inside of the case 4 as shown by the arrows, a narrow groove portion 16 and a wide groove portion 17 are simultaneously formed in the peripheral wall portion 1 of the case 4.

The present invention has the above-described structure, and the positioning of the yoke plate and the bracket relative to the case can be performed simultaneously with a simple structure, thereby reducing the number of parts, improving work efficiency, and reducing costs.

[Brief explanation of the drawing]

Figure 1 is an exploded perspective view of the main parts of a conventional small motor.
Fig. 2 is an exploded perspective view of the main parts of a small motor according to an embodiment of the present invention, Fig. 3 is a perspective view of the small motor after assembly is completed, Fig. 4 is a plan view showing the case machining process, and Fig. 5 is a perspective view of a punch used in the process. 1... Peripheral wall portion, 4... Case, 5... Rotor,
6...Yoke plate, 8...Bracket, 10...Permanent magnet, 11...Protrusion, 13...Brush, 14...
...Brush holder, 16...Narrow groove portion, 17...Wide groove portion.

Claims (1)

[Scope of utility model registration request] A small motor in which a rotor, a yoke plate holding a permanent magnet, and a bracket to which a brush holder is attached are sequentially inserted into a case having a side wall, at least one protrusion on the outer periphery of the yoke plate; A protrusion wider than the protrusion of the yoke plate is provided on the outer periphery of the bracket, and at least one narrow groove part having a groove width approximately the same size as the protrusion of the yoke plate is provided on the side wall of the case, and the width thereof is At least one wide groove having a groove width of approximately the same size as the protrusion of the bracket provided above the narrow groove is provided in series, and the protrusion of the yoke plate is placed in the narrow groove of the case, and the protrusion of the bracket is placed in the wide groove of the case. A small motor characterized in that a yoke plate and a bracket are positioned relative to a case in the axial and circumferential directions by fitting the protrusions into the respective protrusions.