Timepiece mechanism provided with a magnetic gear

A timepiece mechanism, comprising a magnetic gear (2) including a first wheel (6A) and a second wheel (6B), the first (6A) wheel being provided with first permanent magnetic poles (7) which are arranged so as to form the magnetised teeth of a first magnetic toothing (8) from which first magnetic fluxes having alternating polarities respectively emerge, the second wheel (6B) being provided with teeth made of a soft ferromagnetic material defining a second magnetic toothing (10), the first wheel (6A) and the second wheel (6B) being arranged such that the first magnetic toothing (8) has a first magnetic coupling with the second magnetic toothing (10) generated by said first magnetic fluxes which momentarily polarise, in magnetic attraction, teeth of the second magnetic toothing (10), which are momentarily located in a first magnetic coupling zone with the first magnetic toothing (8) and thus through which first magnetic fluxes from among said first magnetic fluxes respectively flow, such that the first and second wheels (6A, 6B) magnetically mesh with one another, the magnetic gear (2) defining a first reference half-axis (30) starting from the rotational axis (34) of the second wheel (6B) and intercepting the rotational axis (32) of the first wheel (6A);

• wherein the magnetic gear (2) further comprises a third wheel (6C) provided with second permanent magnetic poles (9) which are arranged so as to form the magnetised teeth of a third magnetic toothing (12) from which second magnetic fluxes with alternating polarities respectively emerge, the third wheel (6C) and the second wheel (6B) being arranged such that the third magnetic toothing (12) has a second magnetic coupling with the second magnetic toothing (10) generated by said second magnetic fluxes which momentarily polarise, in magnetic attraction, teeth of the second magnetic toothing (10), which are momentarily located in a second magnetic coupling zone with the third magnetic toothing (12) and thus through which second magnetic fluxes from among said second magnetic fluxes respectively flow, such that the second and third wheels (6B, 6C) magnetically mesh with one another, the magnetic gear (2) defining a second reference half-axis (36) starting from the rotational axis (34) of the second wheel (6B) and intercepting the rotational axis (38) of the third wheel (6C), the first reference half-axis (30) and the second reference half-axis (36) having a given angle @ therebetween;
• wherein the first permanent magnetic poles (7A) of the first wheel (6A) have a first phase relative to the first reference half-axis (30), and the second permanent magnetic poles (9A) of the third wheel (6C) have a second phase relative to the second reference half-axis (36), the magnetic gear (2) being arranged such that a phase shift between the first and third wheels, defined as the difference between said first and second phases, is constant at all times;
• and
• wherein the magnetic gear is configured, with said angle Φ and said phase shift, to transfer a mechanical torque in the magnetic gear without slippage occurring between the second wheel and the first and third wheels, that is higher than a maximum mechanical torque which can be transferred, without slippage occurring between the second wheel (6B) and the first wheel (6A), in a magnetic gear comprising the first wheel (6A) and the second wheel (6B) without the third wheel (6C).