Citizen Watch Company, Ltd.

Takeaki Shimanouchi

Takanori Nanya

Takayasu Machida

Kazuo Suzuki

Shigeyuki Takahashi

A stator ( ) is made up by bonding a first stator part ( ) made of a high-permeability material to a second stator part ( ) made of a high-permeability material respectively by welding through the intermediary of connections ( ) made of a low-permeability material or a nonmagnetic material, interposed therebetween. Paired recesses ( ) serving as holding torque setting means for holding a rotor ( ) by a magnetic action are formed on the inner periphery of a rotor hole ( ) defined inside the stator ( ) at the position forming an initial phase angle (&thgr; ). A field coil ( ) for excitation is magnetically bonded to opposite ends of the stator ( ), thereby forming a two-pole step motor for a timepiece.

Two-pole step motor for timepiece

A stator ( ) is made up by bonding a first stator part ( ) made of a high-permeability material to a second stator part ( ) made of a high-permeability material respectively by welding through the intermediary of connections ( ) made of a low-permeability material or a nonmagnetic material, interposed therebetween. Paired recesses ( ) serving as holding torque setting means for holding a rotor ( ) by a magnetic action are formed on the inner, periphery of a rotor hole ( ) defined inside the stator ( ) at the position forming an initial phase angle (&thgr; ). A field coil ( ) for excitation is magnetically bonded to opposite ends of the stator ( ), thereby forming a two-pole step motor for a timepiece

2-Pole stepper motor for timepiece

A pair of parallel rectangular windows are punched out in a thin sheet base material having the same thickness as that of a short hand part ( ) including a weight part ( ) of a second hand ( ) so as to form a hand forming part between the pair of windows and a part in the hand forming part forming a long hand part and a mounting part of a hand is pressed so as to form a thin wall part. Then, the second hand in a final shape is punched out from the base material so that a long hand part ( ) and a mounting part ( ) are formed with the thin wall part of the hand forming part and the short hand part ( ) is formed with an original thickness part. Consequently, the second hand for an analog electronic timepiece in which the weight part ( ) is provided on the short hand part ( ) can be easily and securely manufactured only by a press working.

Method of manufacturing hand for analog electronic timepiece

In an analog electronic timepiece in which the rotation of a rotor ( a) step motor ( ) is decelerated through train wheels before it is transmitted an hour hand ( ) and a minute hand ( ), the gravity center of a center wheel composed of a center wheel gear ( ), a center wheel pinion ( ), and a center wheel shaft ( ) to which the minute hand ( ) is mounted is displaced from the axis of the center wheel shaft ( ) to within an angle range of less than &plusmn;90&deg; with respect to the opposite direction to a direction in which a time indicating part ( a) of the minute hand ( ) extends so as to reduce a moment on the center wheel shaft ( ) caused by a combination of the minute hand ( ) and the center wheel. This makes it possible to prevent a hand-skip due to disturbance even if the value of holding energy of the step motor ( ) is reduced.

Growing community of inventors

Hanno, Japan

Takeaki Shimanouchi