Rolling Bearing Grease Life Estimation from Temperature and Speed
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Solution Overview
Problem
Current methods for determining the lifespan of grease in rolling bearings lack precision, as they do not adequately account for the combined effects of mechanical and thermal degradation, leading to inconsistent grease life prediction across various operating conditions.
Innovation Solution
A modified Grease Aging Master Curve is developed, incorporating the Arrhenius equation to correct for thermal effects, which takes into account both shear and temperature influences on grease degradation, allowing for a more accurate prediction of grease life by calculating the imposed energy on the grease based on temperature and speed profiles.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If empirical grease aging models are used, then grease life prediction is simplified, but precision and universality across various operating conditions deteriorate
Solution Approach 1:
The patent transforms the grease aging prediction from using simple time-based parameters to using energy density parameters that incorporate both mechanical work (shear) and thermal effects. By changing the fundamental parameter from time to energy density (combining mechanical and thermal contributions), the model achieves both simplicity and high precision across diverse operating conditions.
Solution Approach 2:
The patent creates a composite prediction model that integrates two separate degradation mechanisms (mechanical shear aging and thermal aging) into a unified energy density framework. This composite approach combines the advantages of both mechanical and thermal models while eliminating their individual limitations, achieving universal applicability.
2Reliability
If separate mechanical and thermal aging models are used, then each degradation mechanism is addressed, but the overall prediction becomes complex and inconsistent
Solution Approach 1:
The patent merges the separate mechanical shear aging model and thermal aging model into a single unified energy density parameter. By combining these two degradation mechanisms into one comprehensive parameter, the system maintains complete coverage of all degradation mechanisms while eliminating the complexity of managing separate models.
Solution Approach 2:
The unified energy density parameter serves multiple functions simultaneously: it captures mechanical shear effects, thermal effects, and their interaction, providing a universal prediction framework that works across all operating conditions without requiring separate models for different scenarios.
3Ease of operation
If traditional grease life models are used, then calculation is straightforward, but accuracy under varying temperature and speed conditions deteriorates
Solution Approach 1:
The patent replaces traditional mechanical time-based calculation methods with an energy-based approach that accounts for the actual physical effects (shear and thermal) on grease. This substitution maintains computational simplicity while dramatically improving accuracy by reflecting the true degradation mechanisms.
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 provides a precise method for determining the remaining grease life in rolling bearings, improving the accuracy of grease life prediction and enabling more effective re-lubrication schedules, thereby extending the operational life of mechanical systems.
Implementation Method 1
A modified Grease Aging Master Curve is developed, incorporating the Arrhenius equation to correct for thermal effects
Implementation Method 2
The mechanical degradation of the grease is mainly caused by pressure and shear
Implementation Method 3
chemical deterioration (mainly at high temperature, e.g., higher than 120° C.)
Data Source
AI summary
A rolling bearing arrangement having a first and a second raceway element, and rolling bodies being arranged between the two raceway elements so that the two raceway elements are rotatable against each other in the manner of a rolling bearing, a space between the raceway elements in which the rolling bodies are rolling off comprising a lubricating grease, at least one sensor element for sensing temperature, at a specific point of the rolling bearing, particularly in the space, and for sensing speed of the rolling bearing and a unit receiving the sensed temperature and speed, calculating from the profiles of the sensed temperature over time and from the speed over time via a calculated energy imposed on the grease a used and/or remaining period of the grease life-time.