Electrical generator or motor structure – Dynamoelectric – Rotary
Reexamination Certificate
2002-03-06
2003-04-22
Ramirez, Nestor (Department: 2834)
Electrical generator or motor structure
Dynamoelectric
Rotary
C310S156030, C310S156560, C310S216055, C310S216006, C310S180000, C310S254100
Reexamination Certificate
active
06552461
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a permanent magnet type rotating electric machine with a field use permanent magnet rotor and, in particular, relates to a permanent magnet type rotating electric machine mounted for such as a compressor in an air conditioner.
2. Conventional Art
Conventionally, permanent magnets having a variety of configurations were used for this sort of permanent magnet type rotating electric machine. For example, JP-A-6-339241 (1994) discloses a permanent magnet type rotating electric machine which includes a stator to which concentratedly wound armature windings are applied so as to surround a plurality of teeth formed in a stator core and a rotor accommodating permanent magnets in a plurality of permanent magnet insertion holes formed in a rotor core and of which output is improved by making use of its reluctance toque.
The above conventional art intends to improve output torque of the rotating electric machine, however, when reducing into an actual practice of such rotating electric machine, a problem of noises of such rotating electric machine can not be forgotten. Namely, since the concentrated windings increase ripple torques in comparison with conventional distributed windings and which frequently causes problem of noises.
SUMMARY OF THE INVENTION
An object of the present invention is to provide a permanent magnet type rotating electric machine which resolves the noise problem even if concentrated windings are used therefor.
In order to achieve the above object, one aspect of the present invention proposes a permanent magnet type rotating electric machine comprising a stator of which concentratedly wound armature windings are disposed in a plurality of slots formed in a stator core so as to surround teeth and a rotor accommodating permanent magnets in a plurality of permanent magnet insertion holes formed in a rotor core, wherein a part of outer circumferential faces of slots is formed to extend in parallel with a part of inner circumferential faces of the teeth.
Further, another aspect of the present invention proposes a permanent magnet type rotating electric machine comprising a stator of which concentratedly wound armature windings are disposed in a plurality of slots formed in a stator core so as to surround teeth and a rotor in which around a rotor core permanent magnets are disposed and around the outer circumference thereof, a non-iron metal is covered, wherein a part of outer circumferential faces of slots is formed to extend in parallel with a part of inner circumferential faces of the teeth.
Effective countermeasures for reducing the noises of a permanent magnet type rotating electric machine are either to reduce electromagnetic excitation force of the noise origin cause or to remove a resonating structural body caused thereby.
The present invention proposes structures result from a variety of studies performed in view of removing the resonating structural body.
Namely, through provision of a part of outer circumferential faces of slots in a stator core extending in parallel with a part of inner circumferential faces of teeth thereof, oscillation of magnetic pole pieces of the teeth is prevented, thereby, a permanent magnet type rotating electric machine with reduced vibration and noises can be provided.
REFERENCES:
patent: 4741677 (1988-05-01), Frigo
patent: 5838086 (1998-11-01), Cuenot
patent: 6353275 (2002-03-01), Nishiayma
patent: 06-339241 (1994-06-01), None
Hirayama Hiroshi
Kawaminami Shigeya
Kikuchi Satoshi
Koharagi Haruo
Noma Keiji
Crowell & Moring LLP
Hitachi , Ltd.
Mohandesi Iraj A
Ramirez Nestor
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