JPS63220749A - Magnet protecting mechanism for rotary electric machine of permanent magnet type - Google Patents

Abstract

PURPOSE:To tightly shield a rare earth permanent magnet from open air, by filling up a space section between a yoke and a magnet cover with a filler. CONSTITUTION:A rotor 3 with a rare earth permanent magnet 2 combined integrally with the cylindrical inner periphery of a yoke 1 is provided with the members of a core 4 wound up with a coil, a commutator 5 with which a brush 5a elastically comes in sliding contact, and the like. The rare earth permanent magnet 2 is placed in a space section between the yoke 1 and a magnet cover 6, and is retained. Besides, the space section generated between the magnet cover 6 and the yoke 1 is filled up with a filler 7, and the rare earth permanent magnet 2 is perfectly shielded from open air.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a magnet protection structure for a permanent magnet type rotating electrical machine such as an electric motor or a generator, which is constructed using rare earth permanent magnets.

[Prior art and problems to be solved by the invention] Generally speaking, in this type of permanent magnet type rotating electric machine, the material of the permanent magnet assembled on the inner peripheral surface of the yoke has recently been changed to alnico or ferrite. from.

Materials using rare earth elements such as samarium and neodymium, which have excellent magnetic properties, are being adopted. However, so-called rare earth permanent magnets containing these rare earth elements have problematic properties other than their magnetic properties, such as those that easily react with oxygen in the air and are easily oxidized, or those that are brittle and easily chipped. Conventionally, magnets have been plated or painted separately and coated with a protective film, but these work processes are laborious and complicated, and not only do they increase costs, but the magnets are sometimes chipped when assembled. The actual situation is that the protective film is often not able to play a sufficient role, and further improvements are needed.

[Means for Solving the Problems] In view of the above-mentioned circumstances, the present invention was created for the purpose of providing a magnet protection structure for a permanent magnet rotating electrical machine that can eliminate these drawbacks. In a permanent magnet rotating electric machine in which a rare earth permanent magnet is sandwiched between the inner peripheral surface of a cylindrical yoke and a magnetic cover fitted inside the yoke, a space between the yoke and the magnetic cover is It is characterized by being filled with a filler and covering the rare earth permanent magnet from the outside.

With this configuration, the present invention enables the rare earth permanent magnet to be reliably shielded from the outside air.

[Example] Next, in Figure 8, which describes an example of the present invention based on the drawings, 1 is a yoke in a permanent magnet type electric motor, and the cylindrical inner circumference of the yoke 1 has a , a rare earth permanent magnet 2 is integrally assembled as will be described later. On the other hand, 3 is a rotor, and the rotor 3 is provided with members such as a core 4 around which a coil is wound and a commutator 5 with which a brush 5a elastically slides.

Reference numeral 6 denotes a magnetic cover fitted into the yoke 1, and the magnet 2 is held in the space S between the magnetic cover 6 and the yoke 1.
One end side is open apart from the inner peripheral surface of the yoke, and the other end side is almost in close contact with the inner peripheral surface of the yoke 1. Reference numeral 7 denotes a filler to be filled in the space S, and examples of the material include silicone resin, polycarbonate resin, urea resin, phenol resin, wire resin, polyamide resin, and acrylic resin. Organic or inorganic resin materials with properties such as heat resistance, oxidation resistance, and chemical resistance, such as resins, polyester resins, epoxy resins, and polysulfone resins, are used, and as a filling method. is filled with a liquid material and thermally cured or subjected to a monopolymerization reaction, or by an appropriate means that does not affect the incorporated magnet 2, such as filling by injection of a molten resin material. A hard or elastomer filler 7 is formed to cover the rare earth permanent magnet 2 from the outside with the filler 7 to isolate it from the outside air.

In an embodiment of the invention constructed as described.

The magnet 2 is held between the space S between the yoke 1 and the magnet cover 6, and the space S created between the magnet cover 6 and the yoke 1 is filled with a filler 7. The rare earth permanent magnet 2 is completely isolated from the outside air. As a result, the magnet 2 is not exposed to the outside air and remains effective for a long period without being oxidized, even if it is made of a material that is easily oxidized by oxygen in the air. It will be possible to protect it. Moreover, since the filler 7 is filled with the magnet 2 sandwiched in the space S between the yoke 1 and the magnet cover 6, the filler 7 also actively prevents the magnet 2 from shifting. In addition, it is possible to reliably prevent the magnet 2 from chipping and the material surface being exposed, as in the case of assembling a plated or painted item.

Therefore, an unprecedentedly high level of coating protection for the magnet 2 can be reliably achieved by simply filling the space S with the filler 7, and an extremely reliable rotating electric machine can be provided at a low cost. .

[Operation and Effect] In summary, since the present invention is constructed as described above, although the rare earth permanent magnet is sandwiched in the space between the yoke and the magnet cover, the space between the yoke and the magnet cover is Filling with filler not only prevents the rare earth permanent magnet from shifting, but also ensures that the rare earth permanent magnet is coated securely and prevents the material surface from being exposed to the outside air. It will be possible. Therefore, even if rare earth permanent magnets are formed using materials that are brittle and easily oxidized, the unprecedented high degree of protection of rare earth permanent magnets can be achieved by simply filling the void with filler. It is possible to provide an extremely reliable rotating electric machine at a low cost, by using reliable means.

[BRIEF DESCRIPTION OF THE DRAWINGS] The drawings show an embodiment of the magnet protection structure for a permanent magnet rotating electric machine according to the present invention. FIG. 3 is an enlarged sectional side view of the main part. In the figure, 1 is a yoke, 2 is a rare earth permanent magnet, 6 is a magnet cover, and 7 is a filler.

Claims (1)

[Claims] In a permanent magnet rotating electric machine in which a rare earth permanent magnet is sandwiched between the inner peripheral surface of a cylindrical yoke and a magnetic cover fitted inside the yoke, a filling material is provided in the space between the yoke and the magnetic cover. A magnet protection structure for a permanent magnet type rotating electric machine, characterized by filling it with rare earth permanent magnets and covering it from the outside.