GEAR MECHANISM AND TIMEPIECE

摘要

PROBLEM TO BE SOLVED: To provide a gear mechanism which suppresses the strength of a gear, the change of a distance between gears, and the increase of the number of components; and a timepiece equipped with the same.

SOLUTION: A gear mechanism 110 comprises a gear 50 which is a Geneva drive, and a wind-up amount display portion 60 to which rotations of the gear 50 are transmitted. If assuming a module selected for determining dimensions of a tooth of the gear 50 and the wind-up amount display portion 60 as M, tooth thickness corresponding to an arc tooth thickness of the gear 50 as s1, pitch corresponding to the circular pitch of the gear 50 as CP, the arc tooth thickness determined by the module M as tx, the circular pitch as CPx, when the relations are expressed by tx=π*M/2, CPx=π*M, the gear 50 has adjacent teeth 53a and 53b having the pitch CP set to be smaller than the circular pitch CPx, and an outer peripheral portion 56 having a distance from the rotation center of the gear 50 to tip ends of the teeth 53a and 53b as a radius, and provided at a part except for between the teeth 53a and 53b.

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