Cycloidal Magnetic Gear Regulator for Mechanical Watch

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Solution Overview

Problem

Mechanical watch regulating devices with traditional balance-spring and Swiss lever escapements suffer from jerky motion and reduced efficiency due to mechanical friction, while magnetic coupling devices face challenges in maintaining synchronization and motor torque due to reduced magnetic interaction force with increased frequency reduction.

Innovation Solution

A regulating device with a resonator and two annular magnetic structures having different numbers of angular periods, where the resonator undergoes a curvilinear translation around a fixed axis, and a magnetic interaction that maintains resonance mode excitation, utilizing a cycloidal gear mechanism for continuous rotation and anti-unhooking to prevent synchronization loss.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If traditional balance-spring and Swiss lever escapement are used, then mechanical timekeeping is achieved, but jerky motion and reduced efficiency occur due to mechanical friction

Engineering Contradiction:
Improvetimekeeping reliabilityVSAvoidenergy loss due to friction
Core Design Contradiction:
ReliabilityVSLoss of energy

Solution Approach 1:

The patent replaces the traditional mechanical Swiss lever escapement with a magnetic coupling system. The resonator magnet interacts magnetically with the escape wheel magnets, eliminating the need for physical contact and mechanical friction. This substitution maintains timekeeping reliability while dramatically reducing energy loss through frictionless magnetic interaction.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent changes the fundamental operating parameters by using magnetic fields instead of mechanical contact. The magnetic coupling allows for continuous rotation of the escape wheel without the jerky motion characteristic of traditional escapements, as the magnetic attraction and release can occur smoothly without physical impact and friction.

Inventive Principle:
Principle #35Parameter changes

2Reliability

If frequency reduction is increased in magnetic coupling devices, then synchronization between resonator and escape wheel is achieved, but magnetic interaction force decreases

Engineering Contradiction:
Improvesynchronization reliabilityVSAvoidmagnetic interaction force
Core Design Contradiction:
ReliabilityVSForce

Solution Approach 1:

The patent uses multiple annular magnetic tracks arranged in different angular positions around the resonator. This spatial arrangement in multiple dimensions allows the system to maintain strong magnetic interaction forces while achieving the necessary frequency reduction through the geometric configuration of multiple magnetic zones rather than relying solely on increasing the number of periods in a single track.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

Solution Approach 2:

The patent employs multiple annular magnetic tracks that are nested concentrically around the resonator. This nesting arrangement allows the magnetic fields to interact in a layered fashion, maintaining strong coupling forces while the geometric relationship between the nested tracks provides the frequency reduction necessary for synchronization.

Inventive Principle:
Principle #7Nested doll (Nesting)

3Productivity

If continuous rotation is implemented in escape wheel, then efficiency is improved, but mechanical friction and stalling risks increase in traditional designs

Engineering Contradiction:
Improvetimekeeping efficiencyVSAvoidoperational reliability
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The patent replaces mechanical friction-based continuous rotation with magnetic coupling-based continuous rotation. The escape wheel rotates continuously driven by magnetic attraction from the resonator magnet, eliminating mechanical friction at the pivot points and preventing stalling that occurs in traditional mechanical systems. The magnetic force can maintain rotation without the energy losses associated with mechanical friction.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

The device achieves a higher resonator frequency with continuous rotation, enhanced efficiency, and improved synchronization by maintaining a strong magnetic interaction and mechanical drive torque, reducing the risk of stalling and ensuring precise timekeeping.

Implementation Method 1

The first and second magnetic structures are arranged to exhibit a magnetic interaction such that the aforementioned relative rotation of the second magnetic structure, upon application of a driving torque within a useful torque range, excites said resonance mode

Methodology Applied
Scientific EffectMagnetic interaction: Magnetism

Data Source

PatentEP3191898B1Regulator device for the operation of a mechanical timepiece movement
Publication Date: 2020.03.04 ETA SA MFG HORLOGERE SUISSE
  • EP3191898B1 patent drawingFigure 1~2
  • EP3191898B1 patent drawingFigure 3A~3B
  • EP3191898B1 patent drawingFigure 3C~3D

AI summary

The regulator device (2) for the operation of a mechanical timepiece movement comprises: - a chassis (4); - a resonator fixed to said chassis and comprising a first annular magnetic structure (8) having a first number N1 of magnets, arranged regularly in a circle, and an elastic structure (20,21,22); - a second annular magnetic structure (14) having a second number N2 of magnets and defining a central axis (16) around which said structure turns, N2 being different from N1. The resonator is arranged such that a resonance mode in which the first magnetic structure undergoes a curvilinear movement, preferably substantially circular, around the central axis can be excited by the rotation of the second magnetic structure. The two magnetic structures define a cycloidal magnetic gearing such that the regulator device incorporates a frequency reducer between the resonance frequency and the frequency of rotation of the second magnetic structure rigidly attached to an escapement wheel.