Elevator Traction Diagnosis via Acceleration-Dependent Rope Feed
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Solution Overview
Problem
Conventional elevator diagnosing devices fail to accurately diagnose traction performance due to neglect of dynamic factors affecting the relative positional relationship between the sheave and main rope, leading to inaccurate threshold settings and increased complexity with the need for encoders in both the hoisting machine and speed governor.
Innovation Solution
An elevator diagnosing device that controls the elevator car's acceleration/deceleration to detect differences in main rope feed amount using a single encoder on the hoisting machine, distinguishing between slippage and displacement caused by dynamic tension differences, allowing for accurate traction performance assessment without a speed governor encoder.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If conventional elevator diagnosing devices use a single encoder in the hoisting machine, then device complexity is reduced, but measurement precision of rope slippage deteriorates due to inability to distinguish dynamic displacement from actual slippage
Solution Approach 1:
The patent applies dynamics by performing diagnosis under two different acceleration conditions (first acceleration and second acceleration). By comparing the rope feed amounts under these different dynamic conditions, the system can distinguish between displacement caused by dynamic factors and actual slippage, thereby maintaining measurement precision without requiring additional encoders.
Solution Approach 2:
The patent changes the acceleration parameter to perform multiple measurements. By varying the acceleration condition (first acceleration vs. second acceleration) and comparing the resulting rope feed amounts, the system can extract accurate slippage information from dynamic measurements, resolving the contradiction between simple configuration and precise measurement.
2Ease of operation
If conventional devices perform diagnosis under normal acceleration conditions, then ease of operation is improved, but measurement precision deteriorates because dynamic displacement is indistinguishable from slippage
Solution Approach 1:
The patent intentionally introduces dynamic conditions by performing diagnosis under different acceleration levels. This dynamic approach allows the system to separate dynamic displacement effects from actual slippage, improving measurement precision while maintaining operational simplicity through automated multi-condition testing.
Solution Approach 2:
The system uses feedback by comparing rope feed amounts under different acceleration conditions. The control unit calculates the difference between measurements taken under first and second acceleration, using this feedback to determine actual slippage, thereby achieving precise measurement without complicating the operation.
3Ease of manufacture
If threshold values are set without considering dynamic factors, then ease of manufacture is improved, but reliability of diagnosis deteriorates due to inaccurate threshold settings
Solution Approach 1:
The patent changes the acceleration parameter during diagnosis to establish accurate threshold values. By performing measurements under different acceleration conditions and analyzing the differences, the system can set reliable thresholds that account for dynamic factors, ensuring diagnosis reliability without complicating the manufacturing process.
Solution Approach 2:
The system performs preliminary diagnosis under different acceleration conditions to establish accurate threshold values before actual operation. This preliminary action ensures that thresholds are set considering dynamic factors, improving reliability while keeping the manufacturing process simple.
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 more accurate and cost-effective traction performance diagnosis with a simplified configuration, considering dynamic factors and preventing slippage by adjusting acceleration/deceleration, thus improving maintenance efficiency.
Implementation Method 1
a sheave (20) around which a middle portion of a main rope (10) that suspends an elevator car (2) is wound
Implementation Method 2
determination means configured to determine traction performance of the sheave, based on the difference in the amount of feed of the main rope
Data Source
AI summary
An elevator diagnosing device includes a hoisting machine including a sheave, around which a middle portion of a main rope suspending an elevator car is wound, and a controller controlling travel of the elevator car by controlling operation of the hoisting machine. The controller includes a car controller performing first travel control causing the elevator car to travel at a first acceleration/deceleration and second travel control causing the elevator car to travel at a second acceleration/deceleration less than the first acceleration/deceleration, a rope feed amount difference detector detecting a difference in feed amount of the main rope by rotation of the sheave when the elevator car travels equal distances under the first and second travel controls, and a determiner determining traction performance of the sheave based on the difference in the amount of feed of the main rope detected by the rope feed amount difference detector.