Angular speed regulating device for a wheel set in a timepiece movement including a magnetic escapement mechanism

A device for regulating the relative angular speed between a magnetic structure and a resonator magnetically coupled so as to define together an oscillator forming said regulating device, the magnetic structure including at least one annular magnetic path centred on an axis of rotation of said magnetic structure or of the resonator, the magnetic structure and the resonator being arranged to undergo a rotation relative to each other about said axis of rotation when a drive torque is applied to the magnetic structure or to the resonator;

• the resonator including at least one element for magnetic coupling to said annular magnetic path, this annular magnetic path being at least partially formed of a first magnetic material arranged so that the magnetic potential energy of the oscillator varies angularly in a periodic manner along the annular magnetic path and so that it defines an angular period of said annular magnetic path;
• said magnetic coupling element having an active end portion, located on the side of said magnetic structure, which is formed of a second magnetic material, of which at least one physical parameter is correlated to the magnetic potential energy of the oscillator but different therefrom, and which is magnetically coupled to the annular magnetic path so that an oscillation along a degree of freedom of a resonant mode of the resonator is maintained within a useful drive torque range applied to the magnetic structure or to the resonator and so that a determined integer number of periods of said oscillation occurs during said relative rotation in each angular period of the annular magnetic path, the frequency of said oscillation thus determining said relative angular speed;
• wherein said annular magnetic path has a dimension along said degree of freedom of the magnetic coupling element which is smaller than the dimension along this degree of freedom of said active end portion of the magnetic coupling element;
• wherein the resonator is arranged relative to the magnetic structure so that said active end portion is traversed, in orthogonal projection to a general geometric surface defined said active end portion, by a geometric circle passing through the middle of the annular magnetic path during substantially a first vibration in each period of said oscillation;
• wherein, within said useful drive torque range, said annular magnetic path and said magnetic coupling element define, in each angular period, as a function of the relative position defined by their relative angular position and the position of the coupling element along its degree of freedom, a magnetic potential energy accumulation area in the oscillator;
• and wherein said second magnetic material is arranged so that, at least in one area of said second magnetic material magnetically coupled at least partially to said annular magnetic path for relative positions of said annular magnetic path with respect to magnetic coupling element corresponding to at least one part of the magnetic potential energy accumulation area in each angular period, said physical parameter gradually increases angularly or gradually decreases angularly.