Reduction Gear Life Estimation via Stress Detection
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Solution Overview
Problem
Current life estimation methods for reduction gears are inaccurate due to failure to account for external loads, leading to prolonged machine stoppages and maintenance delays.
Innovation Solution
A life estimation system that includes sensors to detect stress in specific parts of the reduction gear, combined with an estimator using S-N diagram data to calculate the remaining life based on both torque and load information, providing a more comprehensive and accurate estimation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional life estimation methods are used that only consider torque, then the estimation process is simple, but the estimation accuracy is low
Solution Approach 1:
The patent combines multiple detection parameters (torque from motor current and external load from output shaft sensors) into a comprehensive life estimation system. By merging these different stress sources and combining them through stress conversion coefficients, the system achieves accurate life estimation that accounts for both driving torque and external load effects.
Solution Approach 2:
The patent introduces stress conversion coefficients as intermediary elements that translate different types of stresses (torque stress from motor, external load stress from output) into a unified stress metric that can be directly compared with material fatigue data. This intermediary conversion layer enables accurate life estimation without requiring complex direct measurement of internal gear stresses.
2Reliability
If comprehensive stress detection is implemented using multiple sensors, then life estimation accuracy improves, but system cost and complexity increase
Solution Approach 1:
The patent makes the external load sensor serve multiple functions: it detects not only the magnitude of external load but also its direction (tensile or compressive stress). This multi-functionality allows a single sensor to provide comprehensive stress information that would otherwise require multiple specialized sensors, reducing overall system complexity while maintaining high reliability.
Solution Approach 2:
The patent changes the parameter detection approach by using sensors that can detect both magnitude and direction of stress (tensile/compressive). This parameter change enables the system to capture comprehensive stress information from external loads, improving life estimation reliability without proportionally increasing sensor quantity or complexity.
3Loss of time
If early failure detection is implemented through accurate life estimation, then machine downtime is reduced, but measurement and detection difficulty increases
Solution Approach 1:
The patent replaces direct mechanical stress measurement (which would be difficult and require intrusive sensors on gear components) with electrical measurement substitution. By measuring motor current to infer torque stress and using output shaft sensors to detect external load, the system achieves accurate stress detection through easier electrical measurements, reducing detection difficulty while enabling early failure detection.
Data Source
AI summary
The life estimation system is a life estimation system that estimates a life of the reduction gear including a reduction mechanism. The life estimation system includes a sensor that is to be mounted onto the reduction gear and detects information for identifying a stress generated in a specific part of the reduction gear, and an estimating unit that identifies the stress generated in the specific part based on detection information obtained by the sensor and estimates the life of the specific part based on the identified stress.