JPS6240940B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an improvement in a method of manufacturing a commutator for a motor, particularly a commutator for a small motor.

Conventionally, as a manufacturing method for commutators for small electric motors,
A method described in Japanese Patent Publication No. 48-37761 is known. This method uses an extrusion punch having a shaft-like punch and a first machined tooth that is slidably combined on the outer periphery of the punch and that forms a protrusion for fixing a commutator piece and a second machined tooth that forms a terminal piece for connection. Using a forging machine equipped with a punch and a die for upsetting the flanged annular member that is the raw material, the shaft-shaped punch is inserted into the annular member that has been upended in the die, and then the extrusion punch is slid. The first working teeth punch out the inner surface of the annular member to form a protrusion, and at the same time, the second working teeth divide the flanged opening of the annular member to form wiring terminal pieces. .

According to the method, the protrusions for fixing the commutator piece and the terminal pieces for connection can be simultaneously formed on the annular member which is the raw material in one step, but the punching process using the extrusion punch Since the material is partially scraped off and removed as excess material, the material yield is very poor.

This invention was made in order to eliminate the drawbacks of the conventional manufacturing methods mentioned above, and its main purpose is to provide a method for manufacturing commutators with the highest material yield without cutting away material. It is something.

The method for manufacturing a commutator for a motor according to the present invention includes:
A forging machine equipped with a punch having a mold groove on its circumferential surface, an extrusion punch that is slidably assembled on the outer periphery of the punch and whose tip has a stepped tooth shape, and a die for upsetting a cylindrical material. A punch with a mold groove is inserted into the cylindrical material loaded in the die to bring the mold groove into contact with the inner surface of the cylindrical material, and then the cylindrical material is pressurized in the axial direction by an extrusion punch, In this pressurizing operation, in the mold groove part of the punch,
On the inner surface of the cylindrical material, protrusions that will serve as claws for fixing the commutator piece are extruded in the radial direction, and at the same time, the stepped tooth section of the extrusion punch is used to connect the cylindrical mouth part of the cylindrical element to the terminal piece for connection. It is characterized by being molded in parts.

Hereinafter, the method of the present invention will be explained in detail based on the drawings showing an example of its implementation.

1A to 4A and 1B to 4B show the manufacturing process of the commutator. First, a cylindrical material 1 shown in FIGS. 1A and 1B is made. This cylindrical material may be either a cut pipe material or a plate material curved into a cylindrical shape. Next, the cylindrical material 1 is placed in a mold of a forging machine as described below, and pressurized in the axial direction of the cylinder.By this pressurizing operation, a claw part for fixing the commutator piece is formed on the inner surface of the cylindrical material. Convex strip 2 [Figure 2A,
Fig. 2B] is extrusion-molded, and at the same time, the connection terminal piece 3 [Figs. 3A and 3B] is separately molded.

5 and 6 show an example of a forging machine. That is, 10 is a lower die set,
11 is a receiving die, 12 is a die, 13 is an upper die set, 14 is a punch, and 15 is an extrusion punch having a stepped tooth profile 15a at the tip, and the punch 14 has a mold groove 16 formed in a part thereof. ing.

That is, the cylindrical material 1 is put into the die 12, the punch 14 fixed to the upper die set 13 is passed through the material 1, and the punch 14 is lowered to the position where the mold groove 16 comes into contact with the material 1. When the extrusion punch 15 is lowered and pressed, the cylindrical material 1
is pressurized in the direction of its cylindrical axis, and the punch 14
The cylindrical material 1 is plastically deformed toward the mold groove 16, thereby forming a protrusion 2 for forming a claw portion on the inner peripheral surface of the cylindrical material 1. This upsetting forging may be either cold or hot.

Therefore, in the lowering operation of the extrusion punch 15, the stepped tooth profile 15a formed at the tip of the extrusion punch 15 causes the opening of the cylindrical material 1 to open in large numbers as shown in FIGS. 3A and 3B. It is molded separately into terminal pieces 3 for connection.

Next, as shown in FIGS. 4A and 4B, the connecting terminal piece 3 is bent outward at a right angle, and the protruding strip 2 is subjected to a pawl process to form a pawl piece 4.

Further, although not shown, a synthetic resin layer is formed within the cylindrical material, the cylindrical material is separated into commutator pieces by groove processing, and the outer diameter is finished to complete the commutator.

Thus, as mentioned above, the cylindrical material 1 is pressurized in the axial direction of the cylinder in a special forging die, thereby pushing out the flesh of the part that will form the claw piece, and leaving the other parts to the bare minimum necessary to wear out the commutator. By forming the cylindrical material to a thick wall and dividing the opening of the cylindrical material into a number of terminal pieces for connection, it is possible to form the protruding strips for fixing the commutator and the terminal pieces for connection on the cylindrical material in one step. Since they can be molded simultaneously, not only can the manufacturing process of the commutator be greatly simplified, but also the material yield can be maintained at the highest level since there is no cutting into the material.

Further, since the die groove 16 on the punch side for forming the protruding stripes 2 on the inner surface of the cylindrical material 1 is held stationary, there is an advantage that the life of the die is greatly improved. Furthermore, according to the method of upsetting the cylindrical material in a mold, the accuracy and roundness of the outer diameter of the cylindrical material can be significantly improved compared to conventional products, so it is possible to improve the final finish for the outer diameter. The cost may be small, and it can greatly contribute to improving the material yield.

In addition, the protrusion 2 formed in the upsetting forging
is not limited to the shape shown in FIGS. 2A and 3A, but can be formed into various shapes, such as a dovetail shape as shown in FIGS. 7 and 8, by the mold groove 16 of the punch 14. .

As described above, according to the present invention, there is provided a punch having a mold groove on the circumferential surface, an extrusion punch that is slidably assembled on the outer periphery of the punch and has a stepped tooth shape at the tip, and a cylindrical material. A forging machine equipped with a die for upsetting the cylindrical material is used, a punch with a die groove is inserted into the cylindrical material that is uprooted in the die, the die groove is brought into contact with the inner surface of the cylindrical material, and then extrusion is performed. The cylindrical material is pressurized in the axial direction by a punch, and in this pressurizing operation, the mold groove portion of the punch is used to radially form protrusions that will become claws for fixing the commutator piece on the inner surface of the cylindrical material. This method is characterized by extrusion molding in the same direction and at the same time dividing and molding the cylindrical mouth part of the cylindrical material into terminal pieces for connection using the stepped tooth-shaped part of the extrusion punch. It is possible to achieve significant simplification and significant improvement in material yield.

[Brief explanation of the drawing]

1A to 4A are cross-sectional views of a cylindrical material showing an example of the processing order of the method of the present invention, and FIGS. 1B to 4B are partial plan views corresponding to each of the above figures;
FIG. 5 is a longitudinal sectional view of a forging machine used in the method of the present invention, FIG. 6 is a longitudinal sectional view of the forging operation state, and FIGS. 7 and 8 are partial sectional views showing the convex shape of the inner surface of the cylindrical material. . 1... Cylindrical material, 2... Convex strip for fixing commutator piece,
3...Terminal piece for connection, 4...Claw piece, 10...Lower die set, 11...Receiving die, 12...Die, 13...Upper die set, 14...Punch,
15...Extrusion punch, 15a...Stepped tooth profile,
16...Mold groove.

Claims (1)

[Claims] 1. A forging machine equipped with a punch having a mold groove on its circumferential surface, an extrusion punch that is slidably assembled on the outer periphery of the punch and whose tip has a stepped tooth shape, and a die for upsetting a cylindrical material. A punch with a mold groove is inserted into the cylindrical material loaded in the die to bring the mold groove into contact with the inner surface of the cylindrical material, and then the cylindrical material is pressurized in the axial direction by an extrusion punch. In this pressurizing operation, a convex strip serving as a claw for fixing the commutator piece is radially extruded on the inner surface of the cylindrical material using the die groove of the punch, and at the same time, the step of the extrusion punch is A method of manufacturing a commutator for an electric motor, characterized in that the mouth part of a cylindrical element is divided into terminal pieces for connection using a toothed part.