Oxidized Titanium Barrel for Watch Mainspring Friction Reduction
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Solution Overview
Problem
Mechanical timepieces experience energy loss and reduced accuracy due to frequent frictional movements between the main spring and the barrel, with existing solutions like using softer barrel materials not adequately addressing the issue of weight, strength, and corrosion resistance.
Innovation Solution
A titanium or titanium alloy barrel with an oxidized surface treated via plasma electrolytic or microarc oxidation is used, providing a lighter weight, high strength, and reduced friction, while maintaining corrosion resistance and efficient energy transfer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If a softer barrel material like brass is used, then wear and energy loss are reduced, but the weight increases and strength decreases
Solution Approach 1:
The patent uses titanium as the barrel material, which is a single material that simultaneously provides high strength, low weight, and reduced friction. This replaces the traditional brass material that required softness for wear reduction but suffered from weight and strength limitations. The titanium barrel with oxidized surface creates a composite-like effect where the base metal provides structural properties while the oxide layer provides low-friction surface properties.
Solution Approach 2:
The patent applies plasma electrolytic oxidation or microarc oxidation to the titanium barrel surface, changing the surface properties by creating an oxidized layer. This parameter change in surface composition reduces the friction coefficient between the barrel and mainspring, thereby reducing energy loss without compromising the bulk material's strength-to-weight ratio.
2Loss of energy
If a softer barrel material is used, then frictional wear is reduced, but the strength and toughness decrease
Solution Approach 1:
The oxidized titanium surface creates a functional composite structure where the titanium substrate provides high strength and toughness, while the oxide layer provides low-friction surface properties. This resolves the contradiction by separating the structural function (provided by titanium) from the surface friction function (provided by oxide layer).
Solution Approach 2:
The patent applies oxidation treatment specifically to the mating surface of the barrel where friction occurs, while the bulk material remains as high-strength titanium. This local quality change ensures that only the surface has modified friction properties, while the overall barrel maintains high strength and toughness throughout its structure.
3Ease of manufacture
If traditional brass barrel material is used, then manufacturing is easy, but weight is excessive and energy transfer efficiency is low
Solution Approach 1:
The patent applies plasma electrolytic oxidation or microarc oxidation processes to the titanium barrel surface. These are established industrial surface treatment techniques that can be integrated into manufacturing workflows. The oxidation process creates a low-friction surface that improves energy transfer efficiency from the mainspring to the barrel, while the base titanium material maintains good manufacturability through conventional machining and forming processes.
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 titanium alloy barrel with an oxidized surface significantly reduces friction and energy loss, enhancing the accuracy and longevity of the timepiece while maintaining a lightweight and cost-effective design.
Implementation Method 1
The oxidation process is achieved through plasma electrolytic oxidation or microarc oxidation
Implementation Method 2
The oxidation process is achieved through plasma electrolytic oxidation or microarc oxidation
Implementation Method 3
The mating wall surface of the barrel is of oxidized titanium surface. The oxidation process is achieved through plasma electrolytic oxidation or microarc oxidation
Data Source
AI summary
The present invention relates to a timepiece having a barrel, wherein a main spring is located within the barrel, wherein the hardness of the material of the main spring is substantially equal or higher than the hardness of the material of the mating wall surface of the barrel, wherein the mating wall surface of the barrel comprises titanium. Titanium generally gives the barrel a lighter weight compared to other common barrels made of brass. Such characteristic is highly sought after as it reduces the overall weight of te timepiece, thus allowing more components to be included into the timepiece. The titanium surface of the barrel is oxidized by plasma electrolytic oxidation or microarc oxidation, through anodization process. The oxidized titanium surface of the barrel allows less surface frictions between the mating surface of the barrel and the mating surface of the main spring, thus avoiding energy loss while allowing for an efficient energy transfer from the main spring to the barrel. The accuracy of the timepiece can thus be enhanced.