Rotating Shaft Position Detection Using Pre-encoded Gear Encoding
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Solution Overview
Problem
Existing position detecting devices for rotating shafts are bulky due to the need for multiple rotational angle detectors and code recording media, and require high-speed arithmetic processing for real-time absolute position calculation, making them costly and inefficient.
Innovation Solution
A position detecting device with first to third rotational angle detectors, an arithmetic processing unit, and a current position detecting unit, where the device calculates absolute position at initiation and uses a low-speed processing unit to determine current position during rotation, reducing size and cost by eliminating the need for code recording media and high-speed processing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If multiple rotational angle detectors and code recording media are used to detect absolute position, then measurement precision is improved, but device complexity and size increase
Solution Approach 1:
The patent combines multiple detection functions into a single integrated system. The gear structure serves both as a speed reduction mechanism and as a positional encoding element, where the tooth pattern itself encodes absolute position information. This eliminates the need for separate code recording media and multiple independent detectors, resolving the contradiction between measurement precision and device complexity.
Solution Approach 2:
The gear component performs multiple functions simultaneously: it acts as a speed reduction mechanism, a rotational angle detector, and an absolute position encoder. The single gear structure provides both incremental position information through its rotation and absolute position information through its tooth pattern, making it a universal component that replaces multiple specialized components.
2Productivity
If high-speed arithmetic processing is used to calculate absolute position in real-time, then productivity is improved, but device complexity and cost increase
Solution Approach 1:
The patent pre-encodes absolute position information directly into the gear's physical structure through its tooth pattern. This eliminates the need for real-time calculation of absolute position, as the information is already prepared and embedded in the gear geometry. The system only needs to read and interpret the pre-encoded pattern, dramatically reducing computational requirements while maintaining real-time performance.
3Measurement precision
If code recording media with specialized scannable codes are used, then measurement precision is improved, but manufacturing cost increases
Solution Approach 1:
The patent replaces expensive, specialized code recording media with a simple gear structure that can be manufactured using conventional machining processes. The tooth pattern on the gear serves as the encoding medium, which is far cheaper to produce than vapor-deposited or precision-machined code discs, while still providing the necessary positional information.
Solution Approach 2:
The patent extracts the encoding function from separate code recording media and integrates it directly into the gear structure itself. The gear teeth serve dual purposes as both mechanical transmission elements and positional encoding features, eliminating the need for additional code recording components and their associated manufacturing processes.
Data Source
AI summary
At a time that a position detecting device is initiated, an arithmetic processing unit calculates the absolute position of a rotating shaft at the time of initiation, on the basis of first to third analog signals corresponding to first to third angles of rotation, which are detected respectively by first to third rotational angle detectors. During rotation of the rotating shaft, a current position counter detects a current absolute position of the rotating shaft by counting a number of pulses of forward rotation pulses or reverse rotation pulses, corresponding to the first angle of rotation detected by the first rotational angle detector, taking as a standard a total number of pulses corresponding to the absolute position of the rotating shaft at the time of initiation.