Rotary Position Sensor with Arcuate Magnet Biasing
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Solution Overview
Problem
Existing position sensors, both contact-type and magnetic, face limitations such as physical wear leading to signal drift and failure, and inability to provide static positional information, with magnetic sensors relying on magnet movement and lacking in static position detection.
Innovation Solution
A position sensor design featuring at least two magnetic conductive structures, magnets, and a magnetic flux responsive device, with an arcuate magnet providing a biasing field and allowing the device to travel beyond the sensing range without damage, enabling detection of both static and moving positions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If contact-type sensors (potentiometers) are used to detect position, then positional information can be obtained, but physical wear of rotating parts and resistive elements causes signal drift and ultimate failure
Solution Approach 1:
The patent replaces the mechanical contact system (wiping contact on resistive element) with a magnetic field-based sensing system. A magnetic flux responsive device detects changes in magnetic flux caused by magnet movement, eliminating physical contact and wear while maintaining positional measurement capability.
Solution Approach 2:
The patent introduces magnetic field lines as an intermediary between the moving magnet and the stationary flux responsive device. The magnetic flux serves as the mediator that transfers positional information without requiring direct physical contact, thereby eliminating wear.
2Reliability
If magnetic position sensors are used to detect movement, then non-contact sensing is achieved, but they cannot provide information about static position of mechanical components
Solution Approach 1:
The patent employs multiple flux responsive devices positioned at different locations within the magnetic field. These devices are pre-positioned to detect specific portions of the magnetic flux pattern, enabling the system to determine static position by reading the state of all devices even when the magnet is stationary.
Solution Approach 2:
The patent divides the magnetic field detection into multiple segments by using several flux responsive devices positioned at different angular locations. Each device monitors a specific portion of the magnetic flux, and collectively they provide complete positional information including static positions.
3Adaptability or versatility
If the travel of the magnetic flux sensing device is not restrained, then the device may inappropriately come into contact with magnets or structural portions, but restraining it limits the sensing range
Solution Approach 1:
The patent transitions from linear travel of the flux sensing device to rotational movement within a magnetic field. The arcuate path allows the device to sweep through a defined angular range, expanding the sensing capability to cover a broader operational envelope while maintaining safe distances from physical components.
Solution Approach 2:
The patent implements a dynamic sensing approach where the flux responsive device can move along an arcuate path to scan the magnetic field. This dynamic positioning enables the device to access different portions of the magnetic flux pattern corresponding to different mechanical positions, thereby expanding the effective sensing range.
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
The sensor provides reliable static and dynamic positional information without physical movement limitations, allowing continued operation even if damaged, as the magnetic flux responsive device is constrained within a path with a varying magnetic field and benefits from an arcuate magnet's biasing field.
Implementation Method 1
A magnetic flux responsive device is provided which is constrained to travel an arcuate path that extends beyond at least one of the magnets. The arcuate magnet is positioned concentrically with the path and produces a biasing magnetic field therearound.
Implementation Method 2
A Hall effect device disposed within a cylindrical-shaped magnet, the magnet having a magnetic field that varies from a north pole to a south pole as detected along a circular face of the magnet.
Implementation Method 3
The arcuate magnet is positioned concentrically with the path and produces a biasing magnetic field therearound.
Data Source
AI summary
A position sensor for sensing an angular position including at least two magnetic conductive structures, at least two magnets, a magnetic flux responsive device, and an arcuate magnet. The at least two magnetic conductive structures include a first magnetic conductive structure and a second magnetic conductive structure. The first magnetic conductive structure is substantially arcuately parallel with the second magnetic conductive structure. The at least two magnets include a first magnet and a second magnet. The first magnet being magnetically coupled with the first magnetic conductive structure and with the second magnetic conductive structure. The second magnet being magnetically coupled with both the first magnetic conductive structure and the second magnetic conductive structure. The magnetic flux responsive device is constrained to travel a path that is partially located between the first magnetic conductive structure and the second magnetic conductive structure. The path extends beyond at least one of the at least two magnets. The arcuate magnet is positioned concentrically with the path.