TIMEPIECE BARREL ASSEMBLY HAVING A SMALL CORE DIAMETER

摘要

The invention relates to a timepiece barrel assembly (1) comprising a barrel mainspring (2) mounted between a barrel drum (3) and a surface (5) for receiving a barrel core coaxial to said drum (3). Said spring (2) is made from a multiphase cobalt/nickel/chrome alloy having a Young's modulus of between 200 and 240 GPa and a shear modulus of between 80 and 100 GPa, and having a width/thickness ratio of between 9 and 21, and the maximum radius of said core (4), which is made of steel, relative to the swivel axis thereof (D), is less than nine times the maximum thickness of said spring (2), and said barrel assembly (1) comprises, at said spring (2) or said drum (3), a means (6) for limiting the longitudinal play between said drum (3) and said mainspring (2) in the direction of said swivel axis (D).