Thermocompensation type sprung balance, movement and timepiece.

摘要

A high quality thermocompensation type sprung balance is provided, which enables the moment of inertia to be easily and precisely adjusted, while suppressing variations affecting the rate, and which exhibits excellent thermal compensation performance. A spring balance of the thermocompensation type according to the invention comprises a balance (62) which is provided with a balance shaft rotating around a first axis by the power of a hairspring and which comprises a high expansion part (82) and a low expansion part (81) having different thermal expansion coefficients. The rocker (62) thus comprises a deformation part (80) which is deformable in a radial direction as a function of a change in temperature, due to the difference between the thermal expansion coefficient of the high expansion part (82) and the coefficient of thermal expansion of the low expansion portion (81), as well as an adjusting portion (64) comprising a weight (102) having a center of gravity at a position eccentric with respect to a second axis (O2) in the radial direction, and attached to the deformation part (80) so as to be rotatable about the second axis (O2) in a state where at least the movement of the weight (102) in a direction along the second axis (O2 ) is blocked.