Cryocooler, and diagnosis device and diagnosis method of cryocooler
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Solution Overview
Problem
Existing cryocoolers face challenges in accurately detecting abrasion of the motion conversion mechanism, leading to abnormal noise and potential component failure, as the progression of abrasion cannot be reliably associated with cumulative operation time due to individual variations.
Innovation Solution
A diagnosis technique that includes a cryocooler with a motor, a motion conversion mechanism, a measuring instrument to output time-series data on power consumption or current, and a processor to detect abrasion based on intake and exhaust timing data, calculating a sliding surface abrasion parameter to determine the extent of abrasion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If cumulative operation time is used to predict abrasion, then monitoring is simplified, but detection accuracy deteriorates due to individual variations in abrasion progression
Solution Approach 1:
The patent replaces the mechanical/time-based monitoring approach with an electrical field-based approach. By measuring current consumption and power usage of the motor, the system detects abrasion through electrical parameters rather than mechanical observation or time tracking, achieving both ease of operation and high detection accuracy
Solution Approach 2:
The patent introduces electrical current and power consumption as intermediary parameters to detect abrasion. Instead of directly measuring mechanical wear or using time as a proxy, the system uses electrical parameters that change in response to abrasion, providing an accurate and easy-to-monitor indicator of component degradation
2Duration of action of stationary object
If abrasion is detected early, then component lifespan is extended, but additional monitoring equipment and complexity are required
Solution Approach 1:
The patent makes the measuring instrument serving multiple functions: it monitors both the operational status of the motor and the abrasion condition of the motion conversion mechanism. By using the same electrical measurements for both purposes, the system extends component lifespan through early detection without adding separate monitoring equipment
Solution Approach 2:
The system uses the motor's own electrical characteristics (current and power consumption) to detect abrasion in itself and associated components. This self-diagnostic capability allows early detection of wear without external monitoring equipment, extending component lifespan while maintaining simple system architecture
3Measurement precision
If section data including intake and exhaust timing is used for analysis, then abrasion detection accuracy is improved, but data processing complexity increases
Solution Approach 1:
The patent utilizes the periodic nature of the cryocooler's operation (intake and exhaust cycles) to structure the data analysis. By analyzing current and power data at specific periodic points in the operational cycle, the system achieves high abrasion detection accuracy while keeping data processing manageable through regular, predictable analysis intervals
Data Source
AI summary
A cryocooler includes a motion conversion mechanism that converts rotating motion output by a motor into linear reciprocating motion of a displacer and includes a first component and a second component slidably connected to each other, a measuring instrument that is connected to the motor to output time-series data indicating power consumption of the motor or a current flowing through the motor, and a processing unit that detects abrasion of a sliding surface between a first component and a second component of the motion conversion mechanism on the basis of section data including an intake start timing or an exhaust start timing in the time-series data.