JPH0236743A - Rotor and manufacture thereof - Google Patents

Abstract

PURPOSE:To suppress eddy current by winding a thin non-magnetic metal board around a permanent magnet chip by more than one turn. CONSTITUTION:A plurality of permanent magnet chips 9 are fixed through adhesive to the outer circumference of a rotor core 8. A metallic board 10 composed of non-magnetic stainless steel is wound around the permanent magnet chip 9 more than one turn then the ends thereof are jointed through welding or a laser beam. Then it is die casted to produce a rotor 7. By such method, the metallic board to be arranged on the outer circumference of the permanent magnet can be made thin and eddy current can be suppressed.

Description

DETAILED DESCRIPTION OF THE INVENTION (a) Field of Industrial Application The present invention relates to a rotor having permanent magnets and a method for manufacturing the rotor.

(B) Prior Art In general, a conventional rotor having a permanent magnet is described in Japanese Patent Application Laid-Open No. 58-151855. The device described in this publication is one in which the rotor core and permanent magnets are inserted into a cylindrical cover and then integrally molded by die-casting. The purpose was to prevent

(c) Problems to be Solved by the Invention In the conventional rotor configured in this way, the cylindrical cover needs to have a certain thickness for strength reasons, and the magnetic flux from the stator is alternately applied to the cylindrical cover. This caused eddy currents to flow, causing an increase in iron loss.

In view of these problems, the present invention provides a rotor and a method for manufacturing the rotor that suppresses an increase in core loss due to the generation of eddy currents.

(d) Means for Solving the Problems The present invention includes a rotor core, a plurality of permanent magnet pieces attached to the surface of the core, and an outer circumference protection material that covers the outer circumference of the permanent magnet pieces. In manufacturing rotors, permanent magnet pieces are attached to the surface of the rotor core, and non-magnetic thin metal plates are wrapped around the outer periphery of the permanent magnet one or more times, and then the rotor core is permanently It is made by die-casting a magnet piece and a non-magnetic thin metal plate.

(1) By using the rotor and rotor manufacturing method configured as described above, the metal plate provided around the outer periphery of the permanent magnet can be made thinner, and the generation of eddy currents can be suppressed.

(f) Example Embodiments of the present invention will be described below based on the drawings.

FIG. 1 is a longitudinal sectional view of a compressor using a rotor according to the present invention. In the figure, 1 is a closed container, and inside this container there is a
A rotary compression element 4 that can be driven by a rotary shaft 3 of the electric element is housed in the lower side of the dynamic element 2, respectively. The electric element 2 includes a stator 5 fixed to the inner wall of the closed container 1, and a rotor 7 inserted into the rotating shaft 3 through an air gap 6 inside the stator. Figures 2 and 3
The figures are a longitudinal cross-sectional view and a cross-sectional view of the rotor 7.
A plurality of permanent magnet pieces 9 are attached to the outer periphery of the rotor core 8 with adhesive, a metal plate 10 made of non-magnetic stainless steel is wrapped around the outer periphery of the permanent magnet pieces, and the ends are welded or laser beamed. After joining with etc., die-casting is performed using a casting mold 11. The rotor core 8 is provided with a through hole, that is, a vertical hole 20 that penetrates in the axial direction. On the outer periphery of this rotor core 8, four permanent magnets 9 are provided with four poles arranged at approximately 90 degrees each. There is a gap 2 between the permanent magnets 9.
2 is formed, and a notch 21 is provided on the outer periphery of the rotor core 9 that faces and meets this gap 22. Further, the metal plate 10 is provided with a notch 23 for preventing the metal plate 10 from rotating. If molten metal for die casting is poured into the notch 23 and then solidified, the metal plate 10 will be prevented from rotating. At this time, this notch 2
3 is aligned with the space 22 between the joints of the permanent magnets 9, that is, the pole separation position of the permanent magnets 9. As a result, even after die-casting of the rotor 7, the pole separation position remains at the notch 23 at ρ.
It can be easily confirmed from the above, and alignment during magnetization is facilitated. Further, 13° and 14 are end rings of the rotor 7, which are connected via a notch 21 and a gap 22.

The end rings 13, 14 are integrally die-cast by injecting molten metal such as aluminum or zinc from the sprue 19 using a mold as shown in FIG.

In this figure, the casting mold 11 includes an outer cylindrical mold 12 that covers the outer periphery of the rotor core 8, and an end ring having an annular space 15.16 forming an end ring 13.14 provided on both sides of the outer cylindrical mold. It is formed by molds 17 and 18. 1
Reference numeral 9 denotes a sprue completely formed in the end ring mold 17, and is located above the gap 22 between the permanent magnets 9. Further, the inner diameter of the annular space 15 and 16 is made to coincide with the outer circumference of the metal plate 10. As a result, when the rotor 7 is placed in the casting mold 11, the allowable range of finishing dimensional accuracy in the length direction (axial direction) of the rotor 7 is increased. That is, this rotor 7 is of type 1.
There is no need for dimensional processing when fitting it into 1.

After the rotor 7 is placed in the casting mold 11 in this way, when molten metal is injected from the sprue 19, the molten metal first passes through the gap 22 and the notch 21 and goes around to the opposite side of the rotor 7, and at the same time hits the permanent magnet 9. Press it against the metal plate 10. When the molten metal flows to a certain extent and the molten metal pressure increases, the molten metal flows through the vertical holes 20 of the rotor core 8, forming the end rings 13 and 14, and forming the notches 21.
The hot water fills the gaps 22 between adjacent permanent magnet pieces 9, forming a rotation preventing material for the permanent magnet pieces. After the hot water has solidified, it is taken out from the casting mold 11 and magnetized to complete the rotor 7.

Incidentally, FIG. 5 is a perspective view of the metal plate 10 used in the above embodiment, and the metal plate 10 is, for example, a stainless steel plate having a thickness of 1 mm wound twice. Both sides of 10 may be coated.

In the rotor configured in this manner, the thin metal plate 10 reduces the generation of hot water current, improving the operating efficiency of the motor. Incidentally, the plate thickness of the cylindrical cover described in the prior art is generally 0 to 5 mm.

(g) Effects of the invention The present invention provides a non-magnetic thin metal plate on the outer periphery of a permanent magnet piece.
By overlapping the coils more than once, the thickness of the metal plate provided around the outer periphery of the permanent magnet piece becomes thinner, which suppresses the generation of eddy currents, reduces iron loss caused by eddy currents, and improves the efficiency of the motor. can be done.

[Brief explanation of the drawing]

Fig. 1 is a sectional view of a compressor using an embodiment of the present invention;
The figure is a half-sectional view of the rotor shown in Fig. 1, Fig. 3 is a cross-sectional view of the rotor shown in Fig. 2, and Fig. 4 shows a casting mold for pouring hot water into the rotor core. A sectional view showing the configuration, Figure 5 is the third
It is a perspective view of the metal plate shown in the figure. 7...Rotor, 8...Rotor core, stone piece, 1
0...Metal plate. 9...Permanent magnetism

Claims (3)

[Claims] (1) In a method for manufacturing a rotor comprising a rotor core, a plurality of permanent magnet pieces attached to the surface of the core, and an outer circumference protection material that covers the outer circumference of the permanent magnet pieces, the rotor A permanent magnet piece is attached to the surface of the iron core, and a non-magnetic thin metal plate is wrapped around the outer circumference of the permanent magnet piece one or more times, and then the rotor core, permanent magnet piece, and non-magnetic thin metal plate are wrapped. A method for manufacturing a rotor, characterized in that plates are integrally formed by die-casting. (2) The method for manufacturing a rotor according to claim (1), characterized in that both upper and lower surfaces of the metal plate are coated with an insulating film. (3) A rotor core, a plurality of permanent magnets attached to the outer periphery of the rotor core, a non-magnetic metal plate wrapped around the outer periphery of the permanent magnet, and the rotor core, permanent magnets, and metal plate integrated A rotor characterized in that it is equipped with a die-cast molding.