Nonvolatile Multi-Turn Rotation Sensor Using Magnetic Spiral Guide
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Solution Overview
Problem
Existing multi-turn rotation sensors face challenges in providing a non-volatile absolute angular position over greater than 360 degrees due to the reliance on electronic counters, which can reset during power failures, and the addition of mechanical gear systems or power generation increases cost and complexity.
Innovation Solution
A rotation sensor system utilizing an interacting radial guide and spiral guide to move a marker element along a radial path, eliminating the need for electronic counters by using a ferromagnetic marker element and magnetic attraction, allowing for non-volatile multi-turn measurements with reduced friction and contamination risk.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If electronic counters are used to track multi-turn rotations, then absolute angular position over greater than 360 degrees can be measured, but the system loses reliability during power failures as the counter resets
Solution Approach 1:
The patent replaces electronic counters with a mechanical marker element that physically follows a spiral track. The marker's radial position along the spiral track mechanically encodes the number of rotations, eliminating power dependency. This mechanical system naturally retains position information without requiring power or memory storage.
Solution Approach 2:
The spiral track is pre-configured with radial positions that correspond to specific rotation counts. As the marker element moves along the spiral track during rotation, it automatically records the number of turns by its radial position, preparing the measurement in advance without requiring post-processing or memory storage.
2Reliability
If mechanical gear systems are added to create a non-volatile multi-turn sensor, then position retention is improved, but device complexity and cost increase
Solution Approach 1:
The patent extracts the essential function of rotation counting from complex mechanical gear systems and implements it using a simple marker element following a spiral track. This eliminates the need for multiple sensors, gear trains, and associated mechanical components while retaining the non-volatile position tracking capability.
Solution Approach 2:
The patent changes the measurement parameter from angular position only to radial position along a spiral track. This parameter transformation allows a single rotating component to encode both angular and rotational count information in the marker's radial position, eliminating the need for multiple sensors and complex gearing.
3Measurement precision
If multiple rotation sensors and gear trains are used to achieve multi-turn measurement, then measurement range is extended, but friction and potential for mechanical failure increase
Solution Approach 1:
The patent merges the functions of multiple rotation sensors and gear reduction mechanisms into a single integrated system. The marker element simultaneously tracks both angular position and rotation count by following the spiral track, eliminating multiple mechanical components and their associated friction and failure points.
Solution Approach 2:
The patent replaces mechanical gear reduction and multiple sensor systems with a magnetic field-based tracking system. The magnetic marker element follows the spiral track without physical contact, eliminating mechanical friction and wear while maintaining accurate multi-turn measurement capability.
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 provides a cost-effective, low-friction, and non-volatile multi-turn rotation sensor that simplifies the system by eliminating the need for gearing and power sources, ensuring accurate and reliable angular position measurement across multiple turns without the risk of counter reset during power failures.
Implementation Method 1
a magnetic spiral guide which moves a ferromagnetic marker element
Data Source
AI summary
A non-volatile, absolute rotation sensor employs a radial guide and spiral guide rotating with respect to each other to move a marker element continuously along the radial guide so that a distance of the marker element along the radial guide provides an indication of shaft movement over multiple turns. A sensor system senses the distance of the marker element along the radial guide to provide an electric output.