JPS61288758A - Permanent magnet type rotor - Google Patents

Abstract

PURPOSE:To obtain sufficient strength by using as a die-cast material a metal at desired temperature into which a filler such as glass fiber is stuffed, even if the die-cast material is thin which covers the surface of a rotor. CONSTITUTION:From a gate 7 a molten metal is poured which is composed of an alloy of tin and lead stuffed with glass fiber. This molten metal flows into a gap 17 between a fixed mold and a stator iron core 2, forming an upper end ring 4, a lower end ring 5 and a covered layer 6 and anchoring a permanent magnet 3 to the stator iron core 2. In a permanent magnet rotor 1 manufactured in this way, the alloy of tin and lead constituting the covered layer 6 can bring down the casting temperature in molding die-cast lower than in aluminium die-casting as the melting point of alloy thereof is about 250 deg.C and is lower than that of aluminium. Thus, the rotor can secure sufficient strength even if the covered layer is thin.

Description

DETAILED DESCRIPTION OF THE INVENTION (a) Field of Industrial Application The present invention relates to a permanent magnet rotor having permanent magnet pieces attached to the outer peripheral surface of an iron core.

(b) Conventional technology Conventionally, this type of permanent magnet rotor has
As described in Publication No. 29159, etc., a plurality of permanent magnet pieces are attached to the outer peripheral surface of an iron core, and then the surfaces of the iron core and permanent magnet pieces are integrally molded with synthetic resin such as epoxy resin, As described in Japanese Unexamined Patent Publication No. 57-177263, after a plurality of permanent magnet pieces are attached to the outer circumferential surface of an iron core, glass fiber impregnated with a thermosetting resin is wrapped around the outer circumferential surface of the vaginal magnet. The magnet is fixed to the iron core by heating and curing, and the aluminum die-casting after placing a plurality of permanent magnet pieces on the outer circumferential surface of the iron core, as described in Japanese Patent Application Laid-open No. 59-11747, etc. There is a type in which the magnet is integrally fixed to an iron core. These products protect the rotor surface with resin or aluminum to prevent damage to the permanent magnets in the buttons during assembly.

(c) Problems to be Solved by the Invention However, all of the above configurations have the following problems.

Generally, the coating material coated on the outer peripheral surface of the rotor for the purpose of surface protection is required to be as thin as possible in order to ensure an air gap with the stator and maintain the characteristics of the motor. Ru.

However, with the above-mentioned synthetic resins that are integrally molded or those that are wound with glass fiber impregnated with thermosetting resin, sufficient strength cannot be obtained when the thickness of the coating layer is reduced, and the rotor Depending on the rotation speed, there is a problem in that the coating layer is destroyed by centrifugal force and the permanent magnet falls off.

On the other hand, in the case where the magnet is integrally fixed to the iron core using aluminum die-casting, the die-casting material has a high melting point (approximately 66
Since it is made of aluminum (0°C), there is a problem in that the permanent magnet is easily cracked at the temperature during die-casting.

The present invention was developed in view of these points, and it is possible to obtain sufficient strength even if the thickness of the die-cast material coated on the surface of the rotor is thin, and moreover, the permanent magnets are formed by the heat generated during die-casting of the die-cast material. The purpose of the present invention is to provide a permanent magnet type rotor that does not crack.

B) Means for Solving the Problems The present invention provides a permanent magnet rotor in which a rotor core and a plurality of permanent magnet pieces attached to the outer peripheral surface of the core are integrally coated and fixed by die casting. In this case, the die-casting material is a metal having a melting point of 250 to 600° C. and filled with a filler such as glass fiber.

(E) Function By configuring the permanent magnet rotor of the present invention as described above, the coating layer is made of a metal filled with glass fibers, and the strength of the layer can be increased compared to a synthetic resin or the like. By using a metal with a melting point of 250 to 600°C, the temperature during die-casting can be lowered, and the thickness of the coating layer is thin (although sufficient strength can be ensured to ensure sufficient strength during high-speed rotation of the rotor). This prevents the permanent magnet pieces from falling off and also prevents the permanent magnets from cracking due to heat during die-casting.

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

(1) is a rotor core (
2), a plurality of permanent magnet pieces (3) attached to the outer peripheral surface of this iron core, an upper end ring (4) and a lower end ring (4) that cover the surface of this magnet and the end faces of the iron core (2). 5) and a coating layer (6) formed integrally with the rotor. The coating layer (6) is made of a material in which an alloy consisting of tin (35-39%) and lead (65-61%) is filled with glass fiber.

The permanent magnet rotor (1) configured as described above is manufactured by the following method. First, as shown in Figure 3, 5.
Fixed mold (9) with sprue (7) and degassing hole (8)
), a movable mold aυ and 02 having gas vent holes,
The rotor core (2
) and permanent magnet piece (3). Next, the molten metal sprue (7) is made by filling the aforementioned tin and lead alloy with glass fiber.
Pour hot water from This hot water is poured into the recess (15) of the fixed mold (9).
It flows into the recess ae of the movable mold (11) and the gap (I7) between the movable mold a and the stator core (2), and flows into the upper end ring (4), the lower end ring (5), and the coating layer ( 6) and a permanent magnet piece (3) is fixed to the stator core (2).

In the permanent magnet rotor (Ik) manufactured by such a method, tin (melting point: 231.8°C) constituting the coating layer (6)
) and lead (melting point: 327.4°C) has a melting point of approximately 2
50℃, which is lower than aluminum (melting point 2660℃),
The casting temperature during die-casting can be lowered compared to aluminum die-casting, and the permanent magnet piece (3) is prevented from cracking due to the heat during casting. Further, the tin and lead alloy that forms the coating layer (6) is filled with glass fiber in a molten state, and the melting point of the alloy is the melting point of glass fiber (approximately 60
Since the temperature is lower than 0°C, the glass fibers do not melt and serve as reinforcement for the alloy.

Here, in electric motors that are generally equipped with the permanent magnet rotor (1) as described above, the melting temperature of the polyester insulating paper inserted between the windings of the stator is approximately 250°C. Its operating temperature limit is approximately 250°C.

From this, the operating limit temperature of the rotor (1) is 250°C.
The above is desirable.

In other words, when these conditions are taken into account, the die-casting material has a melting point at which the glass fiber does not melt even if it is filled with glass fiber in a molten state, and furthermore, it does not melt up to the limit temperature for use on the stator side. Metals with a temperature of 250 to 600°C are suitable.

In addition, both tin and lead are non-magnetic materials, and their alloy is also non-magnetic, so this alloy does not affect the magnetic flux of the permanent magnet piece (3) and degrades the magnetic properties of the motor. There is no such thing.

In this example, a tin-lead alloy filled with glass fiber was used as the die-casting material, but the die-casting material may be a metal with a melting point of 250 to 600°C filled with a filler such as glass fiber. However, even if lead is filled with carbon fiber, etc., this does not deviate from the scope of the present invention.

(G) Effects of the Invention As described above, the present invention provides a permanent magnet rotor in which a rotor core and a plurality of permanent magnet pieces attached to the outer peripheral surface of the core are integrally coated and fixed by die casting. Since the die-casting material is made of a metal with a melting point of 250 to 600°C and a filler such as glass fiber, it is possible to increase the strength of the coating layer compared to synthetic resin. It can lower the temperature and ensure sufficient strength even if the coating layer is thin, preventing permanent magnet pieces from falling off when the rotor rotates at high speed, and preventing permanent magnet pieces from cracking due to heat during die-casting. This is a reduction of

Further, at this time, there is no possibility that the die-casting material of the permanent magnet rotor melts before reaching the usable limit temperature of the stator side and lowers the usable limit temperature of the electric motor.

[Brief explanation of the drawing]

1 to 3 show one embodiment of the present invention, FIG. 1 is a longitudinal sectional view of a permanent magnet rotor, FIG. 2 is a cross sectional view of the same permanent magnet rotor, and FIG. FIG. 3 is a longitudinal cross-sectional view of the mold. (11...Permanent magnet rotor, (2)...Rotor core, (3)...Permanent magnet piece, (6)...Coating layer. Applicant: Sanyo Electric Co., Ltd. and one other representative Person Patent Attorney Yasuo Sano Figure 3

Claims (1)

[Claims] (1) In a permanent magnet rotor in which a rotor core and a plurality of permanent magnet pieces attached to the outer peripheral surface of the core are integrally coated and fixed with die casting, the die casting material has a melting point of 250 to 600°C. A permanent magnet rotor characterized by being made of metal with a filler such as glass fiber.