Shaft Position Detection Using Electromagnetic Induction
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Solution Overview
Problem
Existing position detection devices for shafts moving forward and backward in an axial direction suffer from inaccuracies due to vibrations and changes in tooth contact, especially when detecting the absolute position over a large stroke range.
Innovation Solution
A position detection device comprising a detection object attached to the shaft, an excitation coil generating an alternating magnetic field, and detection coils arranged along the axial direction, where the magnitude of the voltage induced in the detection coils varies with the position of the detection object.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If magnetoresistive elements and grooves are used for position detection, then the detection mechanism can be implemented, but position detection accuracy deteriorates due to vibrations and tooth contact changes
Solution Approach 1:
The patent replaces the mechanical contact-based magnetoresistive element detection system with a non-contact electromagnetic detection system using coils. The excitation coil generates a magnetic field that interacts with the detection coil to detect shaft position without physical contact, eliminating errors caused by vibrations and tooth contact changes while maintaining detection functionality.
2Adaptability or versatility
If shallow inclination angle grooves are used for absolute position detection over entire stroke range, then detection coverage is improved, but detection accuracy deteriorates due to large errors
Solution Approach 1:
The patent replaces the groove-based mechanical detection system with an electromagnetic field-based detection system using excitation and detection coils. This substitution allows for accurate absolute position detection across the entire stroke range without relying on shallow inclination angle grooves, as the electromagnetic interaction between coils provides both wide coverage and high precision simultaneously.
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 solution enables high-accuracy detection of the shaft's position, minimizing errors caused by vibrations and changes in tooth contact, and allowing for precise detection over the entire stroke range.
Implementation Method 1
an excitation coil for generating an alternating magnetic field
Implementation Method 2
a detection coil arranged along an axial direction of the shaft, wherein a magnitude of a voltage induced in the detection coil varies in accordance with a position of the detection object
Data Source
AI summary
A position detection device for detecting a position of a shaft moving forward and backward in an axial direction is provided with a detection object attached to the shaft, an excitation coil for generating an alternating magnetic field, and a detection coil arranged along an axial direction of the shaft. A magnitude of a voltage induced in the detection coil varies in accordance with a position of the detection object.