Watch Lubrication with Oxide Surfaces and Polyols

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Solution Overview

Problem

Mechanical watches face challenges in achieving low friction between moving parts due to the limitations of traditional lubricants, particularly at low temperatures, where interposed carbon films do not provide improved results compared to traditional lubrication.

Innovation Solution

The use of oxide surfaces with chemical affinity for hydrophilic groups and compounds containing hydrophilic groups, such as C3-C9 polyols, directly associated without an intermediate carbon layer, to achieve low friction coefficients between sliding surfaces.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If a carbon film is interposed between friction surfaces with an additive containing -OH groups, then friction coefficients are reduced to ≤0.06 at high temperatures (80°C), but the lubrication shows no progress compared to traditional lubrication at low temperatures (watchmaking conditions)

Engineering Contradiction:
Improveoperating temperature rangeVSAvoidlubrication effectiveness
Core Design Contradiction:
TemperatureVSReliability

Solution Approach 1:

The patent removes the intermediate carbon layer from the friction surfaces, extracting the element that prevented effective lubrication at low temperatures. By eliminating this barrier, the hydrophilic groups can directly interact with the oxide surfaces, enabling effective lubrication across both high and low temperature ranges.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent uses hydrophilic groups (such as -OH groups from polyols like glycerol) as intermediaries that can directly bond to oxide surfaces without requiring a carbon film. These hydrophilic groups act as mediators between the lubricant and the metal oxide surfaces, forming effective lubricating layers at low temperatures where carbon films fail.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Loss of energy

If traditional lubricants are used between steel and ruby parts, then lubrication is provided, but friction coefficients are not low enough and energy reserve is depleted

Engineering Contradiction:
Improveenergy reserveVSAvoidfriction reduction
Core Design Contradiction:
Loss of energyVSReliability

Solution Approach 1:

The patent changes the chemical parameters of the lubricant by using compounds with multiple hydrophilic groups (such as polyols with at least one third of -OH groups relative to carbon atoms). This chemical modification enables the lubricant to form stronger bonds with oxide surfaces, significantly reducing friction coefficients to ≤0.06 and minimizing energy loss.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent creates a composite lubricating system combining oxide surfaces (ruby, alumina, zirconia) with organic compounds containing hydrophilic groups (polyols). This composite approach leverages the chemical affinity between oxide surfaces and hydrophilic groups to achieve superior friction reduction compared to traditional single-material lubricants.

Inventive Principle:
Principle #40Composite materials

3Reliability

If oxide surfaces with hydrophilic group affinity are directly associated with compounds containing hydrophilic groups without an intermediate carbon layer, then friction coefficients are significantly reduced to ≤0.06, but this requires specific material compatibility

Engineering Contradiction:
Improvefriction coefficientVSAvoidmaterial compatibility
Core Design Contradiction:
ReliabilityVSAdaptability or versatility

Solution Approach 1:

The patent applies local quality by treating only the sliding surfaces with oxide coatings (ruby, sapphire, alumina, zirconia) that have affinity for hydrophilic groups, while other parts of the watch mechanism can remain traditional. This localized approach enables low friction where needed without requiring complete system redesign.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent achieves universality by using polyols with multiple hydrophilic groups that can interact with various oxide surfaces (ruby, sapphire, alumina, zirconia, stainless steel oxides). The same lubricant compound works across different material combinations, providing broad applicability throughout the watch mechanism.

Inventive Principle:
Principle #6Universality (Multi-functionality)

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 approach significantly reduces friction coefficients to values less than or equal to 0.06, providing excellent sliding performance between materials like ruby and steel, as demonstrated by the results obtained with glycerol and other polyols, which are stable over numerous cycles.

Implementation Method 1

a first part in relative sliding on a second part, the first part being formed of oxide or comprising an oxide layer on the surface, the sliding surface having a chemical affinity with hydrophilic groups

Methodology Applied
Scientific EffectHydrophilic interaction: Hydrophile

Implementation Method 2

at least some of the moving parts of which are lubricated by agents with a very low coefficient of friction

Methodology Applied
Scientific EffectLubrication: Lubrication

Data Source

PatentEP2082014B1Watch
Publication Date: 2018.02.14 ROLEX SA
  • EP2082014B1 patent drawingFigure 1
  • EP2082014B1 patent drawingFigure 1

AI summary

The invention relates to a timepiece, mainly a mechanical timepiece, in which at least certain mobile parts are lubricated by agents or compounds having a very low friction coefficient. The timepiece includes a first part capable of relative sliding movement on a second part, the first part being made of an oxide or comprising an oxide surface layer. The timepiece also includes on the sliding surface of the first part at least one compound containing one or more hydrophilic groups selected from C3-C9 polyols having at least one third of -OH groups relative to the number of carbon atoms. The first part may consist of ruby or zirconia and the second part of steel or vice-versa, and the compound containing one or more hydrophilic groups may consist of glycerol or aqueous glycerol.