Grease Evaporation Prediction Using Vapor Pressure and Capillary Force

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Solution Overview

Problem

Existing technologies fail to predict the change in grease evaporation amount due to evaporation, which affects the operation and lifespan of mechanical devices, and there is a need for a method to easily predict this change considering relevant conditions.

Innovation Solution

A prediction method and device that calculate the evaporation amount of grease using a first molar mass based on vapor pressure depression and a second molar mass based on capillary force, considering the base oil and thickener in the grease, and output the calculated change as an evaporation amount.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If grease is used in mechanical devices to reduce friction, then the operation stability is improved, but the grease evaporates over time causing change in amount and viscosity which affects device operation

Engineering Contradiction:
Improveoperation stabilityVSAvoidgrease evaporation
Core Design Contradiction:
ReliabilityVSLoss of substance

Solution Approach 1:

The patent applies preliminary action by predicting the evaporation amount of grease before it actually affects device operation. The prediction device calculates expected evaporation based on grease composition (base oil and thickener properties) and operating conditions, allowing maintenance to be scheduled proactively before grease degradation impacts reliability.

Inventive Principle:
Principle #10Preliminary action

2Duration of action of stationary object

If existing technologies are used without evaporation prediction, then the device operation continues normally, but the change amount due to evaporation cannot be predicted making it difficult to stabilize operation and predict lifespan

Engineering Contradiction:
Improvedevice lifespan predictionVSAvoidevaporation change amount information
Core Design Contradiction:
Duration of action of stationary objectVSLoss of information

Solution Approach 1:

The patent implements feedback by using the predicted evaporation amount to inform maintenance decisions and grease replacement scheduling. The prediction device provides quantitative information about grease degradation, which feeds back into maintenance planning to optimize device lifespan and operation stability.

Inventive Principle:
Principle #23Feedback

3Ease of operation

If grease composition is optimized for low torque performance at low temperatures, then low temperature operation is improved, but evaporation characteristics are not considered affecting long term stability

Engineering Contradiction:
Improvelow torque performanceVSAvoidoxidation stability
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The patent applies parameter changes by considering multiple grease composition parameters (base oil type, thickener type, their ratios) and their combined effect on evaporation. The prediction device evaluates how changes in composition parameters affect both low-temperature performance and evaporation characteristics, enabling optimized grease selection.

Inventive Principle:
Principle #35Parameter changes

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

Enables accurate prediction of grease evaporation amount, considering the influence of vapor pressure depression and capillary force, thereby stabilizing mechanical device operation and predicting its lifespan.

Implementation Method 1

a first molar mass obtained by a first equation based on a vapor pressure depression due to a base oil and a thickener contained in the grease

Methodology Applied
Scientific EffectVapor pressure depression: Vapour Pressure

Implementation Method 2

a second molar mass obtained by a second equation based on a capillary force due to the thickener

Methodology Applied
Scientific EffectCapillary force: Capillary Action

Implementation Method 3

The components of the grease may evaporate over time. As the grease evaporates, the amount and viscosity of the grease change

Methodology Applied
Scientific EffectEvaporation: Evaporation

Data Source

PatentEP4722690A1Grease evaporation amount prediction method, prediction device, and program
Publication Date: 2026.04.08 NSK LTD
  • EP4722690A1 patent drawingFigure 1(a)~1(c)
  • EP4722690A1 patent drawingFigure 2
  • EP4722690A1 patent drawingFigure 3(a)~3(c)

AI summary

This grease evaporation amount prediction method comprises: a calculation step for calculating a change in the amount of grease by using the lesser between a first substance amount and a second substance amount, the first substance amount being obtained by a first formula based on a vapor pressure drop caused by a base oil and a thickener included in the grease, and the second substance amount being obtained by a second formula based on a capillary force according to the thickener; and an output step for outputting the calculated change in amount as the amount of evaporation of the grease.