US 12,074,494 B2
Timepiece mechanism provided with a magnetic gear
Matthias Imboden, St-Blaise (CH); Jean-Pierre Mignot, Pontarlier (FR); Milan Calic, La Conversion (CH); Cédric Nicolas, Neuchâtel (CH); and Jean-Jacques Born, Morges (CH)
Assigned to The Swatch Group Research and Development Ltd, Marin (CH)
Filed by The Swatch Group Research and Development Ltd, Marin (CH)
Filed on Jul. 25, 2022, as Appl. No. 17/872,544.
Claims priority of application No. 21193817 (EP), filed on Aug. 30, 2021.
Prior Publication US 2023/0060562 A1, Mar. 2, 2023
Int. Cl. H02K 49/10 (2006.01); G04B 13/02 (2006.01)
CPC H02K 49/102 (2013.01) [G04B 13/02 (2013.01)] 18 Claims
OG exemplary drawing
 
1. A timepiece mechanism comprising:
a magnetic gear (2) including a first wheel (6A) and a second wheel (6B), the first wheel (6A) being provided with 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 of alternating polarities respectively emerge;
wherein the second wheel is provided with teeth made of a soft ferromagnetic material defining a second magnetic toothing (10), the number of teeth of this second magnetic toothing (10) being greater than that of the first magnetic toothing (8), and having a first magnetic coupling with this first magnetic toothing (8) such that, when one of the first and second wheels (6A, 6B) is driven such that it rotates, the other wheel is also driven such that it rotates, with a first transmission ratio defined by the first and second magnetic toothings, by said first magnetic coupling which is generated, at least for the most part, by magnetic fluxes, from among said first magnetic fluxes, momentarily polarising, in magnetic attraction, teeth of the second magnetic toothing (10) which are momentarily located in a magnetic coupling zone with the first magnetic toothing (8) and thus through which these magnetic fluxes respectively flow; and
wherein the magnetic gear (2) further comprises a third wheel (6C) provided with teeth made of a soft ferromagnetic material defining a third magnetic toothing (12), the number of teeth whereof is also greater than that of the first magnetic toothing (8), the second magnetic toothing (10) being arranged on a rim made of a non-magnetic material with non-magnetic zones between the teeth of this second toothing, the third wheel (6C) being disposed relative to the second wheel (6B) in such a way that the third magnetic toothing (12) has a second magnetic coupling, in said magnetic coupling zone, with momentarily magnetised teeth of the second magnetic toothing (10), such that, when one of the second and third wheels (6B, 6C) is driven such that it rotates, the other wheel is also driven such that it rotates, with a second transmission ratio defined by the second and third magnetic toothings, by said second magnetic coupling which is generated, at least in part, by second magnetic fluxes, respectively emerging from said momentarily magnetised teeth of the second magnetic toothing (10) with alternating polarities, these second magnetic fluxes momentarily polarising, in magnetic attraction, teeth of the third magnetic toothing (12) which are momentarily located in said magnetic coupling zone and thus through which the second magnetic fluxes respectively flow, this magnetic coupling zone defining a magnetic meshing zone for the first, second and third wheels.