ROTARY DRIVE

PURPOSE:To reduce assembling manpower, by forming the coil section with plural types of coil wire having different specific gravities and adjusting the weight of the coil section based on the weight of load. CONSTITUTION:In a magnetic disc drive, plural sheets of discs 1 are mounted on the rotary shaft of a motor and a head 2 is positioned through a rotary drive on one face when the disc rotates. The rotary drive 3 comprises a shaft 4 supported rotatably around the shaft, a carriage 5 secured to the rotary shaft 3 and a voice coil motor 6. The motor 6 comprises a coil section 7 fixed to the carriage 5 and a drive circuit section 8 therefor, where the coil section 7 is formed by winding two types of coil wire having different specific gravities and the weight thereof is adjusted corresponding to the weight of load such as the head 2 thus achieving balanced rotation of the rotary shaft 3. For example, the coil section 7 is formed with copper wire 7a and aluminum wire 7b.