Escape Wheel Coating for Stable Lubrication in Non-Magnetic Escapements
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Solution Overview
Problem
Swiss lever escapement mechanisms made of nickel-plated steel are sensitive to magnetic fields, and materials like nickel-phosphorus (NiP12) face performance degradation under certain climatic conditions, affecting amplitude regularity and stability due to loss of lubrication and aging issues.
Innovation Solution
A method involving a galvanic or chemical deposition of a low-phosphorus nickel or nickel-boron layer on LIGA NiP12 components, such as escape wheels and anchors, to improve lubricant adhesion and stability under varying conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If nickel-phosphorus (NiP12) material is used for escape wheels and anchors, then non-magnetic behavior is achieved, but performance degradation occurs under certain climatic conditions leading to amplitude irregularity and stopping
Solution Approach 1:
The patent applies a composite material structure by depositing a nickel-phosphorus layer (NiP6-9) with controlled phosphorus content onto a substrate. This composite structure combines the non-magnetic properties of nickel-phosphorus with optimized tribological characteristics, achieving both magnetic field resistance and reliable amplitude performance under varying climatic conditions.
Solution Approach 2:
The patent changes the chemical composition parameters by controlling phosphorus content in the nickel-phosphorus layer to be between 6-9%, which is lower than conventional NiP12. This parameter optimization improves lubricant adhesion and reduces aging effects, thereby maintaining amplitude regularity while preserving non-magnetic behavior.
2Object-affected harmful factors
If LIGA NiP12 components are used, then non-magnetic behavior is achieved, but lubricant adhesion deteriorates causing oil spread and loss of lubrication at contact surfaces
Solution Approach 1:
The patent optimizes the phosphorus content parameter in the nickel-phosphorus coating to 6-9%, which creates an optimal surface chemistry for lubricant adhesion. This parameter change prevents oil spread and maintains stable lubrication at the contact between the wheel tooth and the ruby lift, while preserving the non-magnetic properties of the LIGA component.
3Object-affected harmful factors
If NiP12 material is used for escape wheels, then non-magnetic behavior is achieved, but aging resistance decreases leading to performance degradation
Solution Approach 1:
The patent reduces phosphorus content from conventional NiP12 to optimized NiP6-9, which significantly improves aging resistance. The lower phosphorus content creates a more stable surface that resists chemical degradation over time, extending the service life of the non-magnetic escape wheel while maintaining its magnetic field resistance.
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
Enhances lubricant retention, ensuring consistent amplitude and reducing aging, with improved shock resistance and stability in climatic variations.
Implementation Method 1
the substrate is coated, by galvanic and/or chemical means, at the level of at least one surface of the substrate of the movement, with at least a second material of thin thickness
Implementation Method 2
the substrate is coated, by galvanic and/or chemical means, at the level of at least one surface of the substrate of the movement
Implementation Method 3
better adhesion of the epilame to the material when the amount of phosphorus on the surface is reduced
Data Source
AI summary
A method for manufacturing a watch movement, in which a substrate is made with a first material comprising at least nickel and phosphorus, the substrate is shaped to the geometry of the movement, and the substrate is coated, by galvanic and/or chemical means, at the level of at least one surface of the substrate of the movement, with at least a second material, which constitutes the peripheral layer of the movement at the level of at least one surface of the substrate of the movement, and which comprises at least nickel and is poorer in phosphorus than the first material, or which comprises nickel and is devoid of phosphorus.