JPH0446549A - Manufacture of motor rotor - Google Patents

Abstract

PURPOSE:To measure and inspect the angle or torsion of a skew precisely and to reduce defectiverate, by making minute recessions in the peripheries of steel plates to be laminated and between adjacent slots, when the steel plates are punched. CONSTITUTION:Minute recessions 8 are made at the peripheries of steel plates 3 to be laminated to make a rotor 1, at the time of punching the steel plates 3. The steel plates 3 are so laminate that each recession 8 may be shifted by a specified amount and run in a line by the rotation of the steel plates 3, and the core body 4 is made to have a skew 5 of a specified angle on its peripheral surface. And the bore diameter of a diecast metal mold is made smaller than the diameter of the core body 4, and the core body 4 is inserted into the diecast metal mold in a state of being expanded by heating the diecast metal mold in diecasting. This makes it possible to visualize the skew easily and to measure and inspect the angle or torsion of the skew precisely, even if slots 2 are formed in a closed state, as the lines of the recessions 8, namely the lines the skew 5, remain at both ends of the recessions 8 after the diecast.

Description

[Detailed description of the invention] (b) Industrial application field The present invention relates to a method of manufacturing a rotor for an electric motor.

(b) Conventional technology Conventionally, the rotor manufacturing method for this type of electric motor was
- As disclosed in Publication No. 45785, etc., a laminated steel plate having a plurality of slots inside is formed by press-punching an electromagnetic steel plate as a raw material, and a plurality of laminated steel plates are laminated while sequentially rotating. The conductor is then clamped while forming a skew, then subjected to heat treatment such as burn-off and annealing, and then the secondary conductor is cast and formed using aluminum die-casting.Finally, the outer circumferential surface is cut and rust-proofed. There is.

(c) Problems to be Solved by the Invention However, according to the above configuration, the slots formed in the laminated steel plates are closed inside the steel plates, so the outer peripheral surface of the completed rotor is Even by looking at it, it is difficult to judge whether the skew is properly formed. For this reason, currently, when inspecting the skew angle, a bar of a predetermined shape is passed through a slot in a clamped state before aluminum die-casting, but it is difficult to check whether the skew is twisted or to measure the exact angle. Currently, the defective rate in electrical property tests on finished products is still high.

Another method is to create a so-called oven slot in which the slot is opened at the outer edge of the laminated steel plate so that the skew can be visually observed in the finished product, and pass the molten aluminum through this slot. The molten metal tends to seep out onto the outer surface of the tool, which necessitates cutting the outer surface as a finishing process, which not only impairs productivity, but also requires cutting materials with different hardness (steel and aluminum) at the same time. There is a problem that the lifespan of the bite is shortened.

Furthermore, there is a method of forming a relatively large recess on the outer edge of the laminated steel sheet at the same time as the press punching of the electromagnetic steel sheet, but in this case, there is a problem that chipping is likely to occur in the mold and the life of the mold is shortened. Furthermore, there is a problem in that the edges of the recesses make it difficult to perform air gap extraction work that will be performed later.

The present invention has been developed in view of these points, and it eliminates the need for cutting the outer peripheral surface, improves productivity, reduces costs, prolongs the life of the tool and mold, and also reduces the skew of the rotor. An object of the present invention is to provide a method for manufacturing a rotor of an electric motor, which allows visual inspection of the skew and allows accurate and easy inspection of the skew.

(d) Means for Solving the Problems The present invention involves forming a core by sequentially rotating and stacking a plurality of laminated steel plates having slots inside and clamping them while forming a skew, and then die-casting the core. When the laminated steel plate is punched, four small parts are formed on the outer periphery of the laminated steel plate located between adjacent slots, while the inner diameter of the die-casting mold is made slightly smaller than the outer diameter of the core. By forming the core in advance and inserting the core into the die-casting mold in a state where the die-casting mold is heated and thermally expanded during die-casting,
This company manufactured rotors for electric motors.

(e) Effect The method for manufacturing a rotor for an electric motor according to the present invention has the above-mentioned configuration.
It has the following effects.

■ Due to the minute recesses formed on the outer periphery of the laminated steel plate, skew can be easily seen even when the slot is closed inside the steel plate, and the skew angle and torsion can be measured and inspected. can be carried out accurately and reduce the defective rate.

■Since the four parts are formed in a minute area between adjacent slots during press punching of a laminated steel plate, the formation of the recess will not deform the laminated steel plate or the slot, and the recess has a depth of 2 Since it is as small as /100 m'm, it does not impair the electrical characteristics of the rotor.

■ Unlike oven slots, hot water during die-casting does not spill over the outer circumferential surface of the rotor, so there is no need to cut the outer circumferential surface, improving productivity and reducing costs.

■Since the recesses are minute, even if a die for punching laminated steel plates is used, there will be no chipping of the die, and the life of the die can be extended.

(f) Example Embodiments of the present invention will be described below with reference to the drawings.

1 is the rotor of the electric motor. This rotor is made by press punching an electromagnetic steel plate as a material to form a disc-shaped laminated steel plate 3 having a plurality of closed slots 2 inside.The laminated steel plate is sequentially rotated at a predetermined angle to The core body 4 is formed by laminating the steel plates and engaging the caulking protrusions 9 provided on each of the steel plates.A skew 5 is formed on the outer circumferential surface of the core body 4 to improve the starting torque. After heat treatment such as burn-off to remove mechanical strain and restore magnetic properties, and annealing to remove press oil and restore electrical properties, aluminum die-casting is performed to form the inside of the slot 2 and the core body. The end face of the core body 4 is wrapped and molded with aluminum to form the secondary conductor and the end ring 6, and finally, the outer peripheral surface of the core body 4 is blued for the purpose of anti-corrosion treatment to complete the core body 4.

Here, in this rotor, the laminated steel plates 3 are punched out, and minute recesses 8 are formed in the outer peripheral surface of the laminated steel plates 3 using a punching die for the steel plates. This recess 8 is
The outer edge of the laminated steel plate 3 has a depth b of 2/100 mm.
, and the length C is 1 mm. Here, the diameter a of the laminated steel plate 3 is 54.38 mm. The recesses 8 are successively shifted by a predetermined amount as the laminated steel plate 3 rotates, and a skew 5 of a predetermined angle formed in the core body 4 is marked on the outer peripheral surface of the core body 4. lamination,
The clamped core body 4 is inserted into a die-casting mold, and the inner diameter of the die-casting mold is 54.37 mm, which is slightly smaller than the diameter of the core body 4. That is, the core body 4 is inserted into a die-casting mold which is heated and expanded by the heat during die-casting. Then, the diameter of the core body 4 after die-casting becomes 27100 mm due to the die-casting mold shrinking due to natural cooling.
It is finished about ~3/100mm smaller. At this time, the core body 4 is pressed by the die-casting mold and finished small, but the recess 8 is not pressed by the die-casting mold, so the recess 8
As shown in FIG. 4, the outer peripheral surface of the core body 4 forms a flat surface between the road surface and the outer peripheral surface of the core body 4. Here, although the four parts 8 have a flat surface as a whole, there is a minute difference in level between the outer peripheral surface of the core body 4 and the outer peripheral surface of the core body 4 at both ends. The lines are clearly visible even after die casting.

The rotor of an electric motor formed by such a method has the following effects.

■A minute recess 8 is formed on the outer periphery of the laminated steel plate 3, and the line of the recess 8 remains clearly on both ends of the die-cast e, so the slot 2 is formed in a closed state inside the steel plate. The skew 5 can be easily visually observed even when the skew 5 is not in use, and the angle and torsion of the skew 5 can be accurately measured and inspected.
Moreover, defects in skew 5 can be detected early, and rotor 1
electrical defect rate can be reduced. Here, the above is
It was confirmed through experiments that the skew mark 5 was clearly visible even after the outer peripheral surface of the rotor 1 was blued.

■Since the recess 8 is formed between the adjacent slots 2, the laminated steel plate 3 is
There is no deformation of the slot 2, and the depth b of the recess 8 is only about 27,100 mm.
The magnetic properties and electrical properties of the rotor 1 are not impaired.

- Unlike oven slots, hot water during die-casting does not spill onto the outer circumferential surface of the rotor 1, so cutting of the outer circumferential surface is not necessary, improving productivity and reducing costs.

■As mentioned above, the four parts 8 are minute, so they can be easily formed using a die for punching the laminated steel plate 3. However, since almost no four parts remain after die casting, the core body 4 The outer circumferential surface can be finished into a substantially perfect circle, and the air gap creation work that will be performed later as an electric motor can be performed satisfactorily.

■Recently, with advances in mold precision and die-casting technology, products have been produced that allow the outer circumferential surface of the rotor 1 to be finished without cutting, and are particularly useful for this type of product.

(G) Effects of the Invention As described above, the present invention provides the following effects.

■Minute four parts are formed on the outer periphery of the laminated steel plate, and the line of the four parts remains clearly at both ends of the four parts even after die casting, making it easy to prevent skew even if the slot is formed with the steel plate closed inside. The skew angle and torsion can be visually observed, the skew angle and torsion can be measured and inspected accurately, and skew defects can be detected early, reducing the electrical failure rate of the rotor.

■Since the four parts are formed between adjacent slots, the laminated steel plate and the slots will not be deformed when forming the four parts when punching the laminated steel plate.2 Also, since the four parts are small, the rotor's magnetism It does not impair the characteristics or electrical properties.

■Unlike open slots, hot water during die-casting does not spill onto the outer circumferential surface of the rotor, so there is no need to cut the outer circumferential surface, improving productivity and reducing costs.

■As mentioned above, the recesses are minute, so they can be easily formed using a die for punching laminated steel sheets, and since almost no recesses remain after die-casting,
The outer peripheral surface of the core body can be finished in a nearly perfect circle,
As an electric motor, air gap opening work that will be performed later can be performed well.

[Brief explanation of the drawing]

Fig. 1 is a front view of a rotor showing an embodiment of the present invention. Fig. 2 is a vertical sectional view of the core body. Fig. 3 is an enlarged view of section A in Fig. 2. Fig. 4 is section A after die casting. FIG. 1. Rotor, 2.-slot, 3. Laminated steel plate, 4
... Core body, 5 ... Skew, 8 ... Recess.

Claims (1)

[Claims] (1) A plurality of laminated steel plates having internal slots are successively laminated while rotating and clamped while forming a skew to form a core, and then this core is cast-in by die casting, in which the laminated steel plate At the time of punching, a minute recess is formed on the outer periphery of the laminated steel plate located between adjacent slots, and the inner diameter of the die-casting mold is formed slightly smaller than the outer diameter of the core. A method of manufacturing a rotor for an electric motor, comprising inserting a core into the die-cast mold in a heated and thermally expanded state.