Patent ID: 6169644
Filing Date: 2001-01-02
Classification: G11B,H02K

Abstract:
A read/write device according to the present invention comprises: heads for writing data on and reading data recorded on a disk-shaped recording medium; a carriage which is equipped with the heads and is supported to as to be able to move in the radial direction of the recording medium; a stepper motor for moving the carriage stepwise; and a medium drive motor for spinning the recording medium, wherein the stepper motor comprises: a rotor which has an annular magnet alternately magnetized with different polarities in a circumferential direction and has a rotary shaft on which is formed a spiral portion engaging the carriage; a first stator which is formed from multilayer magnetic material and is fixedly positioned so as to surround the rotor; a second stator which is formed in substantially the same way as the first stator and is fixedly positioned so as to surround the rotor; and a holder which rotatably retains the rotor and houses the first and second stators, wherein each of the first and second stators comprises: a plurality of teeth which protrude toward the magnet and are arranged at regular intervals around the magnet; a joint section which joins together the base ends of the teeth and has gap angle limitation sections for limiting the angle formed between adjacent teeth; and a coil including drive coils formed on the individual teeth and a cross-over line for electrically connecting the drive coils; and wherein the first and second stators are fixedly positioned such that they are spaced a predetermined distance away from each other along the rotary shaft of the rotor and such that they are offset from each other by a predetermined angle in a rotation direction.