SHAFT-TYPE LINEAR MOTOR AND DRIVE METHOD THEREFOR

PROBLEM TO BE SOLVED: To provide a shaft-type linear motor which is provided with a barshaped stator, containing filed magnets and a mover provided with an armature coil, and can be efficiently driven with less fluctuation in thrust and with small mover width, and a drive method therefor. SOLUTION: This linear motor comprises a mover 2 provided with an armature coil 21 comprising coils Lu , Lv , Lw , a stator 1 provided with field magnets 11 a magnetic pole width of which is Pm and the north poles and south poles of which are arranged alternately. The width of each coil is set to Pm /3, and the coils are arranged, so that their center positions are shifted by Pm /3. Hall elements h1 , h2 , h3 are placed on the mover 2 in positions shifted by Pm /6 from the center positions of the respective coils. A constant current in a direction such as to generate electromagnetic force in a drive direction is passed through coils a period, from when the center positions of the coils advance by Pm /6 in the direction of drive from the upstream end in the drive direction in the direction of drive the magnetic poles to when the center positions further advance by 2Pm /3 in the drive direction, based on the polarity of the magnetic pole which each Hall element detects.