Patent ID: 6838792

Claim:
A low-profile stepping motor, comprising: a first stator unit including: a first upper stator yoke having a plurality of pole teeth formed along a semicircular inner circumference thereof; a first lower stator yoke having a plurality of pole teeth formed along a semicircular inner circumference thereof, the plurality of pole teeth meshing with the pole teeth of the first upper stator yoke; and a first coil unit fixedly sandwiched between the first upper and lower stator yokes, a second stator unit including: a second upper stator yoke punched out as one piece integrally with the first upper stator yoke so as to form an upper twin-stator yoke plate, and having a plurality of pole teeth formed along a semicircular inner circumference thereof; a second lower stator yoke punched out as one piece integrally with the first lower stator yoke so as to form a lower twin-stator yoke plate, and having a plurality of pole teeth formed along a semicircular inner circumference thereof, the plurality of pole teeth meshing with the pole teeth of the second upper stator yoke; and a second coil unit fixedly sandwiched between the second upper and lower stator yokes and arranged horizontally flush with the first coil unit, wherein one of the upper twin-stator yoke plate and the lower twin-stator yoke plate is structured such that one half of its pole teeth partitioned in half by a predetermined datum line and open spaces each residing between two adjacent pole teeth of the other half are positioned symmetrically about the predetermined datum line, a resin plate formed simultaneously with a resin which is filled between the pole teeth of the first and second stator units, and a rotor assembly including a cylindrical magnet and rotatably disposed in a circular open space defined by the pole teeth of the first and second stator units.