JPH01138955A - Rotor equipped with permanent magnet - Google Patents

Abstract

PURPOSE:To miniaturize a rotor and increase the mechanical strength of the same, by a method wherein a plurality of permanent magnets is arranged around a cylindrical rotor core while the magnets are fixed by non-magnetic pushing members, having T-sections, and a retaining ring. CONSTITUTION:A plurality of permanent magnets 12 is arranged circumferentially around the outer periphery of a cylindrical rotor core 11, fitted to a rotary shaft 13 and made of a magnetic material, while axial grooves 14, having dovetailed sections, are provided at the intermediate positions of neighboring permanent magnets 12. The magnets 12 are formed so as to be plates, having arced and bent sectional configurations so as to be contacted closely with the outer periphery of the rotor core 11. The vertical sections of the pushing members 15, consisting of non-magnetic material having T- sections, are inserted into the grooves 14 and are fixed to push the permanent magnets 12. A retaining ring 16 is fitted to the outside of the pushing members 15 and the permanent magnets 12. According to this method, the sectional area of the magnetic paths of the permanent magnets 12 may be increased and the rotor core 11 may be miniaturized.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a rotor with permanent magnets for a rotating electric machine in which the rotor core can be downsized and the mechanical strength can be increased.

[Conventional technology]

A conventional example of a rotor with permanent magnets for a rotating electrical machine will be explained based on FIG. In this figure, a cylindrical rotor core 1 made of a magnetic material is fixed to a rotating shaft 3 via a plurality of permanent magnets 2 forming magnetic poles. The permanent magnets 2 are rod-shaped with a rectangular cross section, and are magnetized alternately in opposite directions in the radial direction. The rotating shaft 3 has a core supporting portion having a rectangular cross-sectional shape;
Joint part with permanent magnet 2 and permanent magnet 2 and rotor core l
The joints are each fixed with adhesive or the like.

The rotor core 1 is provided with a slit 4 of an appropriate depth from the inner circumferential side at an intermediate position between adjacent magnetic poles to suppress short-circuit magnetic flux flow between the magnetic poles.

[Problem that the invention seeks to solve]

The structure described above has many drawbacks, such as increasing the magnetic path cross-sectional area of the permanent magnets 2, increasing the size of the rotor core 1, and reducing the mechanical strength of the rotor core 1 due to the slits 4.

SUMMARY OF THE INVENTION In order to eliminate the above-mentioned drawbacks, it is an object of the present invention to provide a rotor with permanent magnets for a rotating electric machine, which is capable of downsizing the rotor core and increasing mechanical strength.

[Means for solving problems]

In order to achieve the above object, the present invention includes a plurality of permanent magnets 12 arranged in the circumferential direction on the outer periphery of a cylindrical rotor core 11, and an axial groove with a dovetail-shaped cross section in an intermediate position between adjacent permanent magnets 12. 14 is provided, and a holding member 15 made of a non-magnetic material and having a T-shaped cross section that is locked in this groove 14 holds down both side edges of the permanent magnet 12, and a retaining ring 16 is fitted on the outside of these to fix the permanent magnet 12. It was designed to do so.

[Effect]

By arranging the permanent magnets 12 on the outer periphery of the rotor core 11, the magnetic path cross-sectional area can be increased, so the rotor core 11 can be downsized, and the permanent magnets 12
The holding member 15 is made non-magnetic, eliminating the need for the slit 4 described in the conventional example, and fixing it with the retaining ring 16. This suppresses the short-circuit magnetic flux flow between the magnetic poles and the rotor core 1.
The mechanical strength of 1 can be increased.

〔Example〕

FIG. 1 shows an embodiment of the present invention, in which a plurality of permanent magnets 12 are circumferentially arranged on the outer periphery of a cylindrical rotor core 11 made of a magnetic material fitted onto a rotating shaft 13. An axial groove 14 having a dovetail-shaped cross section is provided at an intermediate position between the grooves 12 and 12 . The permanent magnets 12 are formed into a plate shape having an arcuate cross-sectional shape so as to be in close contact with the outer periphery of the rotor core 11, and are magnetized alternately in opposite directions in the radial direction.

A holding member 15 made of a non-magnetic material and having a substantially T-shaped cross section is fixed and attached to the groove 14 by inserting its vertical portion, and holds both side edges of the permanent magnet 12 with the horizontal portion of this holding member 15. It is designed to be attached. A retaining ring 16 is fitted on the outside of the holding member 15 and the permanent magnet 12, and is designed to receive and stop part of the centrifugal force of the permanent magnet 12 caused by the rotation of the rotor, thereby fixing the permanent magnet 12. .

This retaining ring 16 may be made of either magnetic or non-magnetic material. The rotor core 11° permanent magnet 12. The joints of the holding member 15 and the retaining ring 16 are fixed with adhesive or the like.

According to the embodiment, the magnetic path cross-sectional area of the permanent magnet 12 can be increased, so the rotor core 11 can be made smaller. Furthermore, since the holding member 15 of the permanent magnet 12 is made non-magnetic and the slit 4 described in the conventional example is not required, it is possible to suppress the short-circuit magnetic flux flow between the magnetic poles and increase the mechanical strength of the rotor core 11. Since the permanent magnets 12 are fixed by the retaining ring 16, the strength of the entire rotor can be further increased. The rotor core 11 can also be made into a block core by processing a round bar, and in this way, the strength can be further increased. When a magnetic material is used for the retaining ring 16, a slight short-circuit magnetic flux flow is generated between the magnetic poles through this, but most of the centrifugal force of the permanent magnet 12 due to rotation is stopped by the retaining member 15. Therefore, the thickness of the retaining ring 16 can be made thinner than the core thickness at the bottom of the slit 4, which was explained in the conventional example.Therefore, since the magnetic resistance of the retaining ring 16 is large, the occurrence of short-circuit magnetic flux current can be reduced as explained in the conventional example. This can be further suppressed.

When a non-magnetic material is used for the retaining ring 16, it is possible to prevent the generation of short-circuit magnetic flux between the magnetic poles, but on the other hand, the magnetic resistance in the gap between the rotor and the stator (not shown) surrounding the rotor increases.
For example, in the case of binding to the outside of the permanent magnet 12 using non-magnetic glass tape or piano wire, the binding thickness must be thicker than the retaining ring 16 to maintain strength. Magnetic resistance can be reduced.

〔Effect of the invention〕

According to this invention, in a rotor with permanent magnets for a rotating electric machine, a plurality of permanent magnets are arranged circumferentially around the outer periphery of a cylindrical rotor core, and the permanent magnets are fixed to the rotor core to form a T-shaped cross section. Since the permanent magnet is held down and fixed by a non-magnetic holding member and a retaining ring fitted on the outside thereof, it is possible to increase the magnetic path cross-sectional area of the permanent magnet, downsize the rotor core, and increase mechanical strength. You can get the effect that you can.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal sectional view of an embodiment of the present invention, and FIG. 2 is a longitudinal sectional view of a conventional example.

Claims (1)

[Claims] 1) A plurality of permanent magnets forming magnetic poles are arranged circumferentially on the outer periphery of a cylindrical rotor core made of a magnetic material, and an axial groove with a dovetail cross section is provided at an intermediate position between adjacent permanent magnets. A permanent magnet characterized in that a holding member made of a non-magnetic material and having a T-shaped cross section is held in place to hold both side edges of the permanent magnet, and a holding ring is fitted on the outside of these holding members to fix the permanent magnet. rotor with.