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Multi-phase flat-type PM stepping motor and driving circuit thereof
| Details |
Inventors: Isozaki, Kouki; Tsuda, Yuichi; Rokunohe, Junji;
Assignee: Japan Servo Co., Ltd. (Tokyo-to, JP)
Primary Examiner: Ramirez; Nestor
Assistant Examiner: Mohandesi; Iraj A
Attorney, Agent or Firm: Oblon, Spivak, McClelland, Maier & Neustadt, P.C.
Disclosed is a multi-phase flat-type PM stepping motor comprising a first motor unit having a first stator unit and a first rotor unit, and a second motor unit having a second stator unit and a second rotor unit. The first stator unit has a plurality of air-core coils that are radially arranged on a first isolating magnetic disc. The first rotor unit has a plurality of permanent magnets that are alternatively magnetized in N-pole and S-pole and radially arranged on a second magnetic disc with a predetermined air gap with respect to the coil surface of the first stator unit. In the same manner, the second stator unit has a plurality of air-core coils that are radially arranged on a third isolating magnetic disc, and the second rotor unit has a plurality of permanent magnets arranged on a fourth magnetic disc. The first and second motor units are coaxial and symmetric with each other about a non-magnetic disc arranged therebetween. |
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DETAILED DESCRIPTION An object of the present invention is to solve the above described problems of the conventional motor and to provide a high-resolution, high-accuracy multi-phase flat-type PM stepping motor with employing a multi-unit construction.
Another object of the present invention is to provide a simple and low-cost driving circuit for the multi-phase flat-type PM stepping motor.
A multi-phase flat-type PM stepping motor of the present invention described in claim 1 comprises a first motor unit that comprises a first stator unit and a first rotor unit, and a second motor unit that comprises a second stator unit and a second rotor unit.
The first stator unit has a plurality of air-core coils that are radially arranged on a first isolating magnetic disc.
The first rotor unit has a plurality of permanent magnets that are alternatively magnetized in N-pole and S-pole and radially arranged on a second magnetic disc with a predetermined air gap with respect to the coil surface of the first stator unit.
In the same manner, the second stator unit has a plurality of air-core coils that are radially arranged on a third isolating magnetic disc, and the second rotor unit has a plurality of permanent magnets arranged on a fourth magnetic disc.
The first and second motor units are coaxial and symmetric with each other about a non-magnetic disc arranged therebetween.
The motor defined in claim 2 is characterized in that the coils arranged on the first stator unit are deviated from the coils arranged on the second stator unit by 1/2 of the coil arrangement angular pitch, and the permanent magnets arranged on the first rotor unit are deviated from the permanent magnets arranged on the second rotor unit by 1/4 of the angular pitch of the magnetic poles having the same polarity.
In such a case, as defined in claim 3, the total number Pr of the N-poles and S-poles of each rotor unit preferably satisfies the following equation: Pr=m.
+-.
2 where m is a phase number.
Further, as described in claim 4 or 5, it is suitable that the phase number of the multi-phase flat-type PM stepping motor is 6-phase or 10-phase
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Generators or Motors 
