Hybrid timepiece oscillator

Patent metadata

Field	Value
Publication number	US-2018024498-A1
Application number	US-201715616241-A
Country	US
Kind code	A1
Filing date	Jun 7, 2017
Priority date	Jul 21, 2016
Publication date	Jan 25, 2018
Grant date	—

Abstract

Timepiece oscillator, comprising a sprung balance assembly including a balance with a rim, which is returned by a balance spring and pivoted with respect to a structure, on a first side by a torsion wire, fixed by an anchoring element to the structure, and on a second side, opposite to the first side, by a contactless magnetic pivot, the balance comprising a first pole embedded with the balance and the torsion wire, this first pole having a symmetry with respect to the axis of the sprung balance assembly, and cooperating with a second pole comprised in the structure, for the magnetic suspension of the first pole, and to exert on the distal end of the torsion wire, opposite to this anchoring element, a magnetic force for tensioning the torsion wire.

First claim

What is claimed is:

1 . A timepiece oscillator, comprising at least one sprung balance assembly including a balance wheel set, itself including at least one balance rim and returned by at least one balance spring, wherein said balance wheel set is pivoted with respect to a structure, on a first side by at least one torsion wire, fixed by a stiff anchoring element or by means of a parachute spring to said structure, and on a second side, opposite to said first side, by a contactless magnetic pivot, said balance wheel set comprising at least a first pole embedded with said balance wheel set and said at least one torsion wire, each said at least one first pole having a symmetry with respect to a plane passing through the axis of said sprung balance assembly, said at least one first pole cooperating with at least one second pole comprised in said structure, for the magnetic suspension of at least one said first pole, and to exert on the distal end of said at least one torsion wire, opposite to said anchoring element, in a resultant magnetic field with axial symmetry, a magnetic force for axially tensioning said at least one torsion wire, for the axial holding of said torsion wire, and a magnetic force for radially centring said balance wheel set:

2 . The oscillator according to claim 1 , wherein at least one said first pole has a symmetry of revolution with respect to said axis of said sprung balance assembly.

3 . The oscillator according to claim 1 , wherein at least one said first pole cooperates by means of magnetic attraction with at least one said second pole.

4 . The oscillator according to claim 3 , wherein each said first pole cooperates by means of magnetic attraction with at least one said second pole.

5 . The oscillator according to claim 1 , wherein at least one said first pole cooperates by means of magnetic repulsion with at least one said second pole.

6 . The oscillator according to claim 5 , wherein each said first pole cooperates by means of magnetic repulsion with at least one said second pole.

7 . The oscillator according to claim 1 , wherein one said first pole is a movable weight independent of said balance wheel set.

8 . The oscillator according to claim 1 , wherein one said second pole is a pole piece with symmetry of revolution about said axis and independent of any external energy source.

9 . The oscillator according to claim 1 , wherein said at least one torsion wire is a bundle grouping together a plurality of said torsion wires regularly distributed around said axis and each supported on a plane passing through said axis or on an helix developing around said axis.

10 . The oscillator according to claim 1 , wherein said at least one torsion wire is a single torsion wire extending at least along said axis.

11 . The oscillator according to claim 1 , wherein said at least one torsion wire includes a slender portion extending substantially in the direction of said axis, and at least one radial extension shoulder for the attachment thereof to a roller comprised in said balance wheel set, and/or an axial portion comprised in said balance rim, and/or to a collet comprised in said balance wheel set for the attachment of a said balance spring, and/or to said movable weight.

12 . The oscillator according to claim 11 , wherein each said shoulder is substantially flat, and is arranged for insertion into a slot comprised in said balance rim, and/or into a collet comprised in said balance wheel set for the attachment of a said balance spring, and/or into said movable weight.

13 . The oscillator according to claim 11 , wherein said at least one torsion wire is a single torsion wire extending at least along said axis, and comprising a single radial shoulder grouping together all of said shoulders.

14 . The oscillator according to claim 11 , wherein said at least one torsion wire is a single torsion wire extending at least along said axis, and comprising a first pair of shoulders, among said radial extension shoulders, grouping together two said shoulders, for the attachment thereof to said roller and to said axial portion of said balance rim, and a second pair of shoulders grouping together two said shoulders, for the attachment thereof to said collet and to said movable weight.

15 . The oscillator according to claim 11 , wherein said at least one torsion wire is a single torsion wire extending at least along said axis, and comprising a single first shoulder among said radial extension shoulders, and a pair of shoulders or a triplet of shoulders from among the other said radial extension shoulders that are different from said first shoulder.

16 . The oscillator according to claim 11 , wherein said at least one torsion wire is a single torsion wire extending at least along said axis, and comprising a first pair of shoulders among said radial extension shoulders, and two separate shoulders from among the other said radial extension shoulders that are different from said first pair of shoulders.

17 . The oscillator according to claim 1 , wherein said at least one torsion wire comprises an end anchoring element for the setting thereof in a main plate comprised in said structure, and extends substantially perpendicularly and overhanging with respect to said plate.

18 . The oscillator according to claim 1 , wherein the torsional stiffness of the set of all said torsion wires comprised in said oscillator is at least ten times lower than the torsional stiffness of the least stiff said balance spring comprised in said oscillator.

19 . The oscillator according to claim 1 , wherein each said torsion wire is made of single crystal silicon, with a rectangular cross-section less than or equal to 5 micrometres×10 micrometres, and is subjected to a magnetic tension force of intensity greater than or equal to 7 mN.

20 . The oscillator according to claim 1 , wherein said movable weight comprises a portion that is conical along said axis and pointed on the side of said pole piece.

21 . The oscillator according to claim 1 , wherein, at rest, along said axis, a play with a value of 5 to 40 micrometres extends between the tip of said conical portion and said pole piece.

22 . The oscillator according to claim 1 , wherein said pole piece is housed inside a setting suspended by a parachute spring to a cabochon housed inside a bridge comprised in said structure, said cabochon includes a pipe forming a radial stop for said movable weight in the event of a shock.

23 . A timepiece movement including at least one said oscillator according to claim 1 .

24 . A watch including at least one said oscillator according to claim 1 .

Assignees

• Montres Breguet Sa
• Montres Breguet Sa

Inventors

• Legeret Benoit
• LENOIR Deirdre
• Sarchi Davide

Classifications

• G04B31/00

  Bearings; Point suspensions or counter-point suspensions; Pivot bearings; Single parts therefor (bearings in general F16C {; manufacture and composition of springs G04B1/145; suspension of oscillating weights G04B5/18; suspension of a pendulum G04B17/02; bearings for electrical measurement apparatus G01R1/10, G01R1/12, G01R11/12, G01R11/14; inserting jewels A44C17/04; inserting cutting diamonds B23P5/00; devices for fixation of bearing jewels, bearing sleeves, or the like G04D3/04}) · CPC title

• F16C32/0427

  for axial load mainly · CPC title

• F16C32/0417

  for axial load mainly · CPC title

• F16C32/04 Primary

  using magnetic or electric supporting means · CPC title

• F16C2370/00

  Apparatus relating to physics, e.g. instruments · CPC title