JPS6226258B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for cutting out the stator core of a small electric motor in which the stator core is directly supported by brackets on both sides.

Figure 1 is a sectional view showing the configuration of an electric motor using this type of core punching.
is a rotor core, 3 is a rotor conductor, 4 is a stator core, 5 is a stator coil, 6 is a bracket that supports the stator core 4 on both sides, 7 is a tightening bolt for tightening the bracket, 8 is a nut, Reference numeral 9 denotes a self-aligning bearing that supports the rotating shaft 1. FIG. 2 shows a core punched 10 constituting the stator core 4 shown in FIG.
This figure shows an example of a plate cut out using the conventional method of blanking (hereinafter referred to as blanking). In the figure, 11 is a groove that accommodates the stator coil 5, and 13 inside the chain line 12 with diameter D is the part that constitutes the magnetic circuit. The outer side 14 of the chain line 12 is a lug through which the tightening bolt 7 passes, and the reference numeral 15 is a through hole for the tightening bolt 7 provided in the lug 14. In addition, part 1 constituting the magnetic circuit
Even if the outer periphery of No. 3 is partially cut out by about 5% of the diameter D, the magnetic properties will not be affected much. Therefore, as shown by the distance A across flats, a portion of the outer circumference is cut out to save on expensive magnetic steel plates. FIG. 3 is a diagram showing a conventional blanking state of the blanking 10 shown in FIG. 2. FIG.
The ear portion 14 outside the chain line 12 shown in FIGS. 2 and 3 has no relation to the magnetic properties, so this ear portion 1
It would be more efficient if the area of 4 could be effectively reduced, and if the material could be further saved, the conventional sheet cutting method shown in Figures 2 and 3 requires dividing the steel plate into multiple rows. However, since the punched plates are arranged adjacent to each other vertically and horizontally, the area of the ear portion 14 becomes large, making it impossible to reduce the amount of steel used.

This invention was made in view of the above points, and it is possible to effectively reduce the area of the ear portion through which the tightening bolt is passed, without changing the shape of the parts that make up the magnetic circuit, and to save on the use of magnetic steel plates. The present invention provides an improved method for cutting out stator cores.

An example of the method of this invention is shown in FIGS. 4 and 5 below.
This will be explained using figures. In the figure, the same reference numerals as in FIGS. 1 to 3 indicate the same or corresponding parts, 16 is a punched board cut out by the method of this embodiment, 17 to 20
17 is a part constituting the periphery of the punched board 16, 17 is the long side with one side length L and the distance between opposite sides is A, 18 is located perpendicular to the long side 17, and the length M of one side is long. The short side is shorter than side length L and the distance between opposite sides is A,
19 has a length of M/2, which is half the length of the short side 18, and draws a parallel line from one end of the long side P to the short side 18,
Straight line portion PQ connecting the intersection Q with the chain line 12, 20
is a diagonally shaded portion RQ connecting one end R of the short side and point Q. Note that if the intersection of the long side 17 and the chain line 12 is S, then the long side 17, the straight line portion PQ19, and the chain line 1
The portion surrounded by 2 forms the ear portion 14.
By configuring the blanking 16 as described above, the area of the lug 14 is reduced compared to the conventional blanking method. FIG. 5 is a diagram showing the cutting state of the punched sheets 16 shown in FIG. 4 according to this embodiment. They are arranged with a 1/2 pitch shift in the direction. A convex portion formed by the short side 18 of the lower row and the hatched portion RQ20 is fitted into a recessed portion formed by the straight line portion PQ19 and the hatched portion RQ20 of the adjacent punched plates 16 in the upper row. Conversely, the protrusions in the upper row are fitted into the recesses formed by the adjacent blanks 16 in the lower row.

Therefore, by performing the cutting in this way, the vertical width W can be reduced compared to the conventional one. Let Wo be the width dimension in the case of two-stage cutting using the conventional board cutting method shown in Fig. 3. Fifth
Assuming that the width dimension in the case of two-stage punching in the sampling method of the present invention shown in the figure is W, the material saving rate α is expressed as α=Wo−W/Wo×100%. Now L/A
= 0.8, the saving rate α in the case of two-stage removal is 5
%, in the case of three-stage punching, it is 6.7%, and the more stages of punching, the less the influence of punching debris caused by the concave portions at the ends in the width direction, and the more the material saving rate improves.

As described above, when the method of the present invention is used, it is possible to reduce the dimensions of the edges of the stator core punching that do not affect the magnetic properties, and it is possible to improve the efficiency of blanking, so there is no need to reduce the electrical properties. Therefore, it is possible to reduce the amount of materials used.

[Brief explanation of the drawing]

Figure 1 is a vertical cross-sectional view of the upper half showing the configuration of a small electric motor, Figures 2 and 3 are for explaining the conventional method of blanking, and Figure 2 is a vertical cross-sectional view of the upper half of the small electric motor. Plan view, Figure 3 is a layout diagram showing the state of board cutting, Figure 4
Figures 5 and 5 show an embodiment of the method of the present invention, in which Fig. 4 is a plan view of the upper half of the cutting board, and Fig. 5 is a layout diagram showing the state of cutting the board. In the drawings, the same reference numerals indicate the same or equivalent parts, 16 is the punched board, 17 is the long side, 18 is the short side, 1
9 is a straight line PQ, and 20 is a diagonal line RQ.

Claims (1)

[Claims] 1. In a stator core cutting method in which blanks are punched out from a steel plate for the core by punching multiple rows, the punching is performed on a short side and a long side where the distance between the opposite sides is equal and perpendicular to each other, and from one end of the long side. parallel to the short side,
It is formed by a straight line part of 1/2 length and a diagonal line part connecting the end of the straight line part and the short side, and by shifting each row by 1/2 pitch, adjacent punches in the upper row are The convex part formed by the short side and the diagonal line part of the lower row fits into the concave part formed by the straight line part and the diagonal line part of the board, and the convex part of the upper row fits into the concave part formed by the adjacent blanks of the lower row. A method for cutting a stator core, characterized in that the plates are cut so that the parts fit together.