JPS6256740B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for manufacturing a commutator for a small electric motor, and particularly to a method for manufacturing a flat type commutator.

FIG. 1 is a plan view of a conventional commutator blank.
After forming a plurality of protrusions 2 and a center hole 4 by punching out a thin copper plate having an outer diameter of D or more,
Each protrusion 2 is bent at right angles in the same direction at a bending part 3 which is the base of the protrusion 2.

FIG. 2 is a cross-sectional view of the commutator blank shown in FIG. 1 taken along the line AB after the projections are bent. The length of the protrusion 2 from the bending part 3 to the tip is a disk shape having legs of the same length. This brush sliding plate 5
After fixing the lower surface of and the protrusion 2 with molding material,
A commutator is obtained by cutting and dividing the brush sliding plate 5 in the radial direction and connecting each protrusion 2 to a coil of an armature.

However, in this manufacturing method, commutator blank 1
A thin copper plate with a diameter of at least D is required to make a copper plate, and the punching area is large, resulting in a large amount of wasted material. Furthermore, the mold used for this punching operation has the drawback of being large and expensive.

In addition, as a method to improve this drawback,
As a method of forming the riser part of the flat plate commutator in Publication No. 27521, for example, the riser B shown in FIG. 3 is punched out together with the commutator piece 9 to form a complicated shape. Since it is used in a flat plate state, it is not outside the range of conventional common sense.

An object of the present invention is to provide a method for manufacturing a commutator for an electric motor that can save materials and can be molded using a small mold. A plurality of L-shaped protrusions are formed concentrically on the disk, and after these L-shaped protrusions are bent toward the back side of the disk and curved inward, the back side of the disk and the L-shaped protrusions are molded with a molding material. The present invention is to form a brush sliding plate by embedding the brush in the radial direction, and to separate the L-shaped protrusions electrically by cutting and dividing the brush sliding plate in the radial direction.

FIG. 3 is a plan view of a commutator blank according to an embodiment of the present invention, in which the same parts as in FIG. 1 are given the same reference numerals. In this case, since the brush sliding plate 5 is punched out so as to form a plurality of L-shaped protrusions 7 around the periphery, a disc having a diameter D' is sufficient as the material needed. If the direct meridian d of the brush sliding plate 5 in FIGS. 1 and 3 is the same, it is obvious that
D'<D, indicating that the commutator blank 6 of FIG. 3 can be made from thin copper sheets of smaller dimensions. Note that the tip 8 of the L-shaped protrusion 7 is connected to the bent portion 3.
If the part is bent downward at a right angle and then bent inward, the state shown in Fig. 4 will be obtained. FIG. 4 is a sectional view through the center hole after the tip 8 of the commutator blank has been bent in this manner. That is, a plurality of tip portions 8 are present below the brush sliding plate 5, indicating that the same shape as that in FIG. 2 can be easily obtained.

FIG. 5 is a vertical sectional view of a commutator obtained by the manufacturing method of this example. The disk portion of the commutator blank 6 and the tip portion 8 are integrally molded with a molding material 9 to reinforce the tip portion 8. In addition, the brush 12 shown by the broken line is in contact with the upper surface of the brush sliding plate 5,
An armature shaft 10 indicated by a broken line is inserted into the center hole 4 . This armature shaft 10 and commutator 11 are fixed by a fixing means not shown in the figure, so when the armature shaft 10 rotates, the commutator 11 also rotates.

6 is a plan view of the commutator 11 of FIG. 5. FIG.
As shown in FIG. 5, after the disk portion and tip portion 8 of the commutator blank 6 are fixed with a molding material 9, slits 13 are cut radially from the center and cut. As a result, a plurality of fan-shaped brush sliding plates 5 each having one tip 8 are obtained, and these tips 8 are respectively connected to the coils of the armature.

In the commutator of this example, a plurality of L-shaped protrusions were punched out along the outer periphery of the brush sliding plate, and the L-shaped protrusions were bent inward at right angles in one direction and reinforced with molding material. Cut the rear brush sliding plate into a fan shape. Since each fan-shaped brush sliding plate is formed with one tip, a commutator can be easily manufactured by connecting this to the coils of the armature. The commutator formed in this way does not easily rattle due to the difference in thermal expansion coefficient between the brush sliding plate 5 and the molding material 9 due to electrical heat generated by contact between the brush 12 and the brush sliding plate 5. It never occurs. By forming the L-shaped protrusion along the outer periphery of the brush sliding plate as described above, it is possible to significantly reduce the size of the material.

FIG. 7, FIG. 8, and FIG. 9 are diagrams for explaining a method of manufacturing a commutator according to an embodiment of the present invention. FIG. 7 is a plan view of the commutator blank 14, in which a thin copper plate is machined into a circular shape, a center hole 4 is punched in the center, and a plurality of L-shaped cuts 15 are machined along the outer periphery. The outer diameter of this commutator blank 14 is
If the diameter d of the brush sliding plate 5 is the same as in FIGS. 3 and 1 as D'', obviously D'' will be the minimum. If the commutator blank 1 shown in Fig. 1 is punched out of a square thin copper plate with one side D'', and the commutator blank 14 shown in Fig. 7 is formed by punching out a square copper thin plate with one side D''. In the case of this embodiment shown in FIG. 7, the size can be reduced by about 40%, and the thin copper plate used as the material can be significantly saved.

FIG. 8 is a plan view of each tip 8 of FIG. 7 bent downward, and FIG. 9 is a sectional view passing through the center hole 4 of FIG. 8. Since FIG. 9 has the same shape as FIG. 4 explained in the previous example, from now on, the fifth
After reinforcing the tip 8 with a molding material 9 as shown in the figure, by processing the slit 13 in the same manner as shown in FIG. 6, a commutator 11 similar to that of the previous embodiment can be obtained.

In the method for manufacturing a commutator of this embodiment, a commutator blank can be obtained by simply providing cuts, so that the amount of material can be further reduced.

Although the above embodiment is an example in which a thin copper plate is used as the material, it is also possible to manufacture the same using a thin aluminum plate.

The method of manufacturing a commutator for an electric motor according to the present invention has the advantage that the amount of materials used can be significantly reduced and the commutator can be manufactured at low cost.

[Brief explanation of the drawing]

Figure 1 is a plan view of a conventional commutator blank, Figure 2 is a plan view of a conventional commutator blank.
The figure is an AB sectional view after bending the protrusions of the commutator blank shown in Fig. 1, Fig. 3 is a plan view of a commutator blank that is an embodiment of the present invention, and Fig. 4 is the view shown in Fig. 3. 5 is a vertical sectional view of the commutator obtained by the manufacturing method of this example, and FIG. 6 is the commutator shown in FIG. 5. , FIG. 7 is a plan view of a commutator blank which is another embodiment of the present invention, FIG. 8 is a plan view showing a state in which the tip of FIG. FIG. 2 is a cross-sectional view through the center hole of the commutator blank shown in the figure; 3...Bending portion, 4...Center hole, 5...Brush sliding plate,
6, 14... Commutator blank, 7... L-shaped protrusion, 8
... Tip part, 9 ... Mold material, 10 ... Armature shaft, 1
1...Commutator, 12...Brush, 13...Slit, 1
5...Cut.

Claims (1)

[Claims] 1. A method for manufacturing a flat motor commutator made of an easily deformable metal plate, in which a plurality of L-shaped protrusions are formed on the outer periphery of a disc constituting a circular brush sliding plate. After concentrically punching out and bending these L-shaped protrusions to the back side at right angles to the disk, the back surface of the disk and the L-shaped protrusions are embedded with molding material, and then 1. A method of manufacturing a commutator for a motor, characterized in that a brush sliding plate is equally divided in the circumferential direction to electrically separate commutator pieces. 2. The method of forming a plurality of L-shaped protrusions concentrically on the outer periphery of the disc is a method of punching out the peripheral part of the disc, leaving a plurality of L-shaped protrusions. A method for manufacturing a commutator for a motor according to item 1. 3. The method according to claim 1, wherein the method of forming a plurality of L-shaped protrusions in the same shape on the outer periphery of the disk is a method of making a plurality of L-shaped cuts in the peripheral portion of the disk. A method of manufacturing a commutator for electric motors.