Magnetic Stroke Sensor Assembly for One-to-One Position Detection
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Solution Overview
Problem
Existing stroke sensors fail to establish a one-to-one correspondence between the position of a moving object with a large range of movement and the rotation angle of the arm portion due to the sinusoidal shape of the guide groove, leading to inaccurate position detection.
Innovation Solution
A stroke sensor that converts linear movement of a moving object into rotational movement of a magnetic field generator relative to a magnetic field detecting element, using a support member to maintain a one-to-one correspondence between the rotation angle and the object's position within a defined rotational movement range, excluding the ends.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If a sinusoidal guide groove is used to enable large range movement detection, then the movement range is extended, but a one-to-one correspondence between position and rotation angle cannot be established
Solution Approach 1:
The guide groove is segmented into a first guide groove with sinusoidal shape for extended range and a second guide groove with different shape (linear or curved) for maintaining one-to-one correspondence. This segmentation allows different portions of the groove to serve different functions: the first groove extends the movement range while the second groove ensures accurate position detection through one-to-one correspondence between rotation angle and position.
2Length of moving object
If the rotational movement range is extended to cover large position changes, then the detection range is increased, but the one-to-one correspondence relationship is lost at the ends of the range
Solution Approach 1:
Different sections of the guide groove are given different local qualities or characteristics. The first guide groove has a sinusoidal shape optimized for extending the detection range, while the second guide groove has a different shape optimized for maintaining reliable one-to-one correspondence. This local differentiation ensures that each section performs its specific function effectively.
3Device complexity
If a potentiometer and arm portion mechanism is used, then the structure is simple, but the position detection accuracy deteriorates for large range movements
Solution Approach 1:
The patent replaces the traditional potentiometer-based mechanical detection system with a magnetic field-based detection system. Instead of using an arm portion that mechanically engages with the guide groove and a potentiometer to detect rotation angle, the invention uses a magnetic field generator and magnetic field detecting element. This substitution eliminates the mechanical coupling issues and enables accurate position detection over large ranges while maintaining structural simplicity.
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 accurate position detection of a moving object over a large range by ensuring a consistent magnetic field detection, reducing sensor size and cost, and maintaining a one-to-one correspondence between rotation angle and position.
Implementation Method 1
a magnetic field generator; a support member that supports the magnetic field generator; and a magnetic field detecting element that detects a magnetic field that is generated by the magnetic field generator
Data Source
AI summary
Stroke sensor 3 for detecting a position of moving object 2 that moves linearly has: magnetic field generator 11; support member 7 that supports magnetic field generator 11; and magnetic field detecting element 14 that detects a magnetic field that is generated by magnetic field generator 11. Support member 7 converts a linear movement of moving object 2 relative to magnetic field detecting element 14 to a rotational movement of magnetic field generator 11 relative to magnetic field detecting element 14. Magnetic field generator 11 moves rotationally in a rotational movement range having two ends, and a one-to-one correspondence is realized between a rotation angle of magnetic field generator 11 and a position of moving object 2 within a region of the rotational movement range that excludes at least the two ends.