Patent ID: 6774513
Filing Date: 2004-08-10
Classification: G04C,H02K

Abstract:
A The two-pole step motor for a timepiece comprising:a rotor including a rotor magnet and a rotor axle; a stator comprising a high-permeability material, having a rotor hole in which the rotor is installed; and a field coil for excitation, including a magnetic core comprising a high-permeability material around which a conductor is wound, and opposite ends of which are magnetically bonded to opposite ends of the stator; wherein the stator comprises a plurality of holding torque setting means disposed on inner periphery of the rotor hole at installation angles differing in a direction of the inner periphery; and wherein at least one of the plurality of the holding torque setting means is formed in shape asymmetrical with respect to a center of the rotor hole, wherein said holding torque setting means formed in a shape asymmetrical with respect to the center of the rotor hole comprises a pair of recesses facing each other, formed on the inner periphery of the rotor hole, on opposite sides of the center of the rotor hole.