Modeling of magnetic field perturbations on the balance-spring of a mechanical watch

Refzul Khairi (1) , Xavier Mininger (1) , Romain Corcolle (1) , Lionel Pichon (1) , Laurent Bernard (1)

1 GeePs - Laboratoire Génie électrique et électronique de Paris

A magnetic field is a major enemy of a mechanical watch. This field may modify the structure of the balance-spring and change its resonance frequency. As a consequence, the watch loses its accuracy. The aim of this work is to quantify the impact of the magnetic field to the balance-spring resonance using a finite element approach. This coupled magneto-mechanical problem implies magnetic forces computation while accounting for a large rotation of the spring. An original algorithm including a dynamic mechanical time-stepping scheme is proposed to quantify the change of the resonance frequency. Index Terms-Mechanical watch, resonance frequency, coupled magneto-mechanic problem.

Domains: Engineering Sciences [physics]; Electromagnetism

Refzul Khairi, Xavier Mininger, Romain Corcolle, Lionel Pichon, Laurent Bernard. Modeling of magnetic field perturbations on the balance-spring of a mechanical watch. 20th International Conference on Computation of Electromagnetic Fields (Compumag 2015), Jun 2015, Montréal, Canada. ⟨hal-01235591⟩