JPH08288163A - Manufacturing method for rotor iron core - Google Patents

Abstract

PURPOSE: To provide a rotor iron core piece which is excellent in roundness of outer diameter, and concentricity of axis hole and outer diameter, by punching stress release holes around a predetermined position of a pole gear with intervals before the pole gear on the periphery of the rotor iron core piece is punched out of a blank metal thin board. CONSTITUTION: At a station A, pilot holes 3 are punched out in a blank metal thin board 1, and at a station B, stress release holes 3 are formed, by punching, around a predetermined position for punching a pole gear of outer diameter of a rotor iron core piece with intervals. Then, a part 5a which is going to be the outer diameter of the pole gear 5 of the rotor iron core piece 4 and an axis hole 6 are punched at the same time at a station C. Caulking parts 7 are, at the core piece 4 laminated in the first place, punched as caulking through holes 7a at a station D, and the core piece 4 after that is punched as caulking protrusion 7b at a station E. Further at a station F, a part 5b other than a part 5a of the outer diameter of the pole gear 5 is punched, so that the core piece 4 is punched, and laminated on the core piece 4 punched in advance with the caulking parts 7 in between.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of manufacturing a rotor core having excellent inner and outer diameter concentricity.

[0002]

2. Description of the Related Art An electric motor uses a laminated iron core in which iron core pieces are laminated. There are various types of electric motors, such as precise rotation
Stepping motors, precision small-sized motors, and the like are used for braking.

In the stepping motor, a rotor having a large number of pole teeth formed on the outer circumference is rotatably provided in a stator having a large number of small teeth formed on the inner ends of magnetic poles, and an air gap between the stator and the rotor is formed. It is narrowed. Further, even in a small precision motor, the air gap between the stator and the rotor is narrowed so as to perform precise rotation control.

Not only the stepping motor but also a motor which requires precise rotation has excellent outer diameter roundness of the rotor and concentricity between the rotor shaft hole and the outer diameter. It is indispensable to be excellent, and it is necessary to eliminate the deviation of micron order.

As a technique for increasing the outer diameter roundness of the rotor and the concentricity of the shaft hole and the outer diameter, for example, in punching a rotor core piece as in Japanese Patent Publication No. 5-72179, the rotor core piece There is one that punches the shaft hole and the outer diameter at the same time. It is said that this has a corresponding effect of improving roundness and concentricity.

[0006]

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention
The material metal thin plates are punched into a desired shape, and are caulked and laminated via the caulking portion. The material metal thin plate has anisotropy due to its manufacturing process, for example, different workability in the rolling direction and the direction orthogonal to the rolling, and because there is residual stress when slit to a predetermined plate width, The stamped rotor core piece has a slight expansion and contraction depending on its location, and a small error of, for example, several microns occurs in the circularity of the outer diameter. Further, the concentricity between the shaft hole of the rotor core piece and the outer diameter is reduced.

According to the present invention, a rotor core piece having excellent concentricity and roundness is punched to obtain a rotor core having excellent characteristics even if the residual stress is present or anisotropy in the thin metal sheet. The purpose is that.

[0008]

SUMMARY OF THE INVENTION The gist of the present invention is to provide a rotor core manufacturing method in which rotor core pieces each having pole teeth on the outer periphery and axial holes formed in the center are punched out and laminated through caulking parts. Before punching the pole teeth on the outer periphery of the rotor core piece from the thin metal plate, intermittently punch the stress relief holes around the pole teeth to be punched, and then simultaneously punch the shaft hole and part of the pole teeth. It is a method for manufacturing a rotor core, which comprises punching and punching and laminating the remaining punched portions of the pole teeth.

[0009]

According to the present invention, since the stress relief holes are intermittently punched around the intended position of the pole teeth before punching the pole teeth on the outer periphery of the rotor core piece from the thin metal plate, The stress when punching and residual stress are released from it,
The stress when punching part of the shaft hole and the magnetic pole at the same time is released, and the punched rotor core piece has excellent roundness of the outer diameter,
Moreover, the concentricity of the shaft hole and the outer diameter is excellent.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will now be described based on one embodiment with reference to the drawings. In the drawing, reference numeral 1 is a thin metal plate, which is a material for punching out rotor core pieces, and 2 is a pilot hole punched by station A.

Numeral 3 is a stress release hole punched by the station B, which is formed intermittently around the outside of the position where the outer pole teeth of the rotor core piece are to be punched. It is preferable that the stress releasing hole 3 is punched out in a ring shape with a small small piece for releasing residual stress and for releasing stress by punching the pole teeth thereafter. The length of the small and short pieces and the intermittent length of the stress release hole 3 are arbitrarily determined.

In the station C, the shaft hole 6 is punched out at the same time as the portion 5a of the pole tooth 5 of the rotor core piece 4 which is the outer diameter. Since the pole teeth 5 have irregularities in the radial direction, the punching of the portion 5a having the outer diameter is a small square in this embodiment, which is punched so as to form a dot array and a ring shape.

Reference numeral 7 is a caulking portion, and the rotor core piece 4 to be first laminated is punched out by the station D as the caulking through hole 7a, and the subsequent rotor core piece 4 is stationed as the caulking protrusion 7b by the station E. Punched out.

In station F, the punched pole teeth 5 are used.
The rotor core piece 4 is punched out by punching out a portion 5b other than the outer diameter portion 5a, and is laminated on the previously punched rotor core piece 4 via the caulking portion 7. In addition, after punching out a part 5a of the outer diameter of the pole tooth 5 in FIG.
The punching of b is enlarged and shown.

According to the present invention, when the outer diameter of the rotor core piece 4 is punched out, the stress releasing hole 3 is formed in advance along the outer side of the rotor iron piece 4, so that the punching stress and the residual stress of the material metal plate are released, It is punched out in a perfect circle without deterioration of shape. Also,
Concentricity is excellent because the shaft hole 6 and the outer diameter portion 5a of the pole tooth 5 are punched at the same time.

[0016]

As described above, according to the present invention, a rotor core piece having excellent roundness and concentricity, which is excellent in shape accuracy, is punched, and the rotor core piece is caulked and laminated has high characteristics. .

[Brief description of drawings]

FIG. 1 is a diagram showing a manufacturing process of a rotor core piece according to an embodiment of the present invention.

FIG. 2 is a diagram showing punching of pole teeth of a rotor core piece according to one embodiment of the present invention.

[Explanation of symbols]

 1 Material Metal thin plate 2 Pilot hole 3 Stress release hole 4 Rotor core piece 5 Pole tooth 6 Shaft hole 7 Caulking part

Claims (1)

[Claims] 1. A method of manufacturing a rotor core, comprising punching rotor core pieces each having a pole tooth on the outer periphery and a shaft hole formed in the center, and laminating the rotor core pieces through a caulked portion. Before punching teeth, punching intermittently stress relief holes around the pole tooth punching planned position, then punching the shaft hole and part of the pole tooth at the same time, punching and laminating the punching residual part of the pole tooth. A method for manufacturing a rotor core, comprising: