Mitsubishi Denki Kabushiki Kaisha

Nidec Copal Corporation

Hidenobu Itou

Takao Mizutani

Kouichi Takamune

A motor with a permanent magnet is provided. A motor has a rotor and an annular drive magnet surrounding the rotor. The drive magnet includes a plurality of magnetized areas having an entire circumference divided into a multiple of at equiangular intervals and includes a plurality of divided areas having an entire circumference divided into the same number as the number of magnetized areas at equiangular intervals. The two adjacent magnetized areas have different polarities. In an inner circumferential surface of each divided area in the drive magnet, a distance D from a rotation center line of the rotor becomes longer from a center in a circumferential direction toward both ends of the area. A magnetization polarization line of the two adjacent magnetized areas deviates from a boundary between the two adjacent divided areas in the circumferential direction.

Motor

An operation command for constructing compensation data is generated in a control device, and measurement data obtained from an external length measuring device is input to an input unit. The measurement data is compared with an estimated position in a control device of a cylinder servo motor, and errors between them is stored in a compensation memory. In addition, in normal operation, the external length measuring device is removed. A movement command is input to the input unit and compensated using the error stored in the compensation memory, so that the estimated error is deleted in the normal operation.

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Tokyo, Japan

Hidenobu Itou