One-Piece Silicon Regulating Member for Timepiece Temperature Stability

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Solution Overview

Problem

The development of regulating members for timepieces is complex due to the different natures of balance wheels and hairsprings, which makes temperature sensitivity and assembly in resonance challenging.

Innovation Solution

A one-piece regulating member is created using silicon-based materials, comprising a balance wheel and a hairspring with a ferrule, where a third silicon-based layer forms a spacing between the ferrule and balance wheel, and the balance wheel includes a rim with an adaptation device to modify inertia and a Grossmann-type curve for improved concentricity, and the hairspring is made more resistant with silicon dioxide.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If separate manufacturing of balance wheel and hairspring is used, then each component can be optimized for its specific function, but the assembly complexity and temperature sensitivity increase

Engineering Contradiction:
Improvetemperature insensitivityVSAvoidassembly complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent merges the balance wheel and hairspring into a single integrated component made of silicon-based material. This consolidation eliminates the assembly step between separate components and ensures that the regulating member has uniform thermal properties throughout, making it insensitive to temperature changes while simplifying manufacturing.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The regulating member is constructed from homogeneous silicon-based material throughout, ensuring uniform thermal expansion characteristics. This homogeneity eliminates the temperature sensitivity issues that arise when assembling different materials with different thermal properties, while also simplifying the manufacturing process.

Inventive Principle:
Principle #33Homogeneity

2Adaptability or versatility

If different materials are used for balance wheel and hairspring, then functional optimization is achieved, but assembly in resonance becomes difficult

Engineering Contradiction:
Improvefunctional optimizationVSAvoidassembly in resonance
Core Design Contradiction:
Adaptability or versatilityVSEase of manufacture

Solution Approach 1:

By combining the balance wheel and hairspring into a single silicon-based component, the patent eliminates the resonance assembly requirement. The integrated structure ensures that both functional requirements are met simultaneously without the need for precise resonance matching between separate components.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The patent changes the material parameter from different materials to a single silicon-based material, which has specific elastic and thermal properties that optimize both the balance wheel and hairspring functions simultaneously, eliminating the need for resonance assembly.

Inventive Principle:
Principle #35Parameter changes

3Manufacturing precision

If traditional assembly methods are used, then component flexibility is maintained, but manufacturing precision and temperature stability are compromised

Engineering Contradiction:
Improveassembly precisionVSAvoidmanufacturing process complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The integration of balance wheel and hairspring into a single component eliminates assembly operations, thereby achieving maximum manufacturing precision without the complexity of resonance assembly processes. The single-piece construction ensures precise geometric relationships are maintained throughout the component.

Inventive Principle:
Principle #5Merging (Combining)

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

This solution minimizes temperature sensitivity and assembly difficulties, providing a robust and precise regulating member that maintains accuracy and reduces manufacturing complexities.

Implementation Method 1

securing by silicon fusion bonding, on the etched upper layer of the substrate, an additional layer of silicon-based material

Methodology Applied
Scientific EffectSilicon fusion bonding: Welding

Implementation Method 2

The inner turn of the balance-spring comprises a Grossmann-type curve in order to improve the concentricity of the development of said balance-spring

Methodology Applied
Scientific EffectGrossmann-type curve geometry: Geometry

Implementation Method 3

the adaptation device comprises recesses made on the rim of the balance in order to be able to adjust the inertia of said balance; the recesses comprise a material of greater density than that of the rim of the balance in order to increase the inertia of said balance

Methodology Applied
Scientific EffectMoment of inertia modification: Moment of Inertia

Implementation Method 4

the hairspring comprises at least one part based on silicon dioxide in order to make it more mechanically resistant and to adjust its thermo-elastic coefficient

Methodology Applied
Scientific EffectThermo-elastic coefficient adjustment: Elasticity

Implementation Method 5

said material of greater density is distributed at the level of the serge in the form of a crenellated ring comprising a succession of studs spaced apart at regular intervals to compensate for the thermal expansion of said material

Methodology Applied
Scientific EffectThermal expansion compensation: Thermal Expansion

Data Source

PatentEP2257856B1Integral adjusting member and method for making same
Publication Date: 2016.11.23 NIVAROX FAR SA
  • EP2257856B1 patent drawingFigure 1~3
  • EP2257856B1 patent drawingFigure 4~6
  • EP2257856B1 patent drawingFigure 7~9

AI summary

The invention relates to a integral adjusting member (41, 41', 41") that comprises a pendulum (43, 43', 43") being in engagement with a hairspring (51, 51', 51") made in a layer of a silicon-based material (21) and including a spiral-spring (53, 53', 53") coaxially mounted on a collet. According to the invention, the collet (55, 55', 55") includes a portion (19) defining an extension protruding from said spiral-spring, made in a second layer of the silicon-based material (5) and attached to the pendulum (43, 43', 43"). The invention also relates to a timepiece including such an adjustment member, and to a related manufacture method. The invention pertains to the field of clock movement.