Rare-Earth Magnetic Encoder Ring for Precise Rotation Sensing
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Solution Overview
Problem
Existing rotation angle and speed measurement technologies, such as optical scanning and resolver-based systems, are sensitive to environmental disturbances and costly, while magnetic encoders lack the precision and durability needed for high-precision applications under varying conditions.
Innovation Solution
A magnetic signaling device with a thin, magnetizable hard magnetic layer made of rare-earth materials, applied to a ductile carrier, which is directly pressed onto a rotating component, using PVD technology for precise magnetization and optimized layer structure, enabling high precision and robustness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If magnetic signals are transmitted through fluid coupling between piston and cylinder, then contactless signaling is achieved, but signal distortion occurs due to fluid interference
Solution Approach 1:
The patent introduces a magnetic field as an intermediary medium to transmit signals between the piston and cylinder without direct fluid coupling. Magnets embedded in the piston and cylinder create a magnetic field that penetrates the fluid coupling, allowing signal transmission while avoiding the distortion problems of direct fluid-based magnetic coupling.
Solution Approach 2:
The patent replaces the mechanical/fluid-based magnetic coupling system with an electronic detection system. Hall effect sensors or magnetoresistive sensors detect changes in the magnetic field caused by piston movement, converting mechanical displacement into electrical signals that are then transmitted through the fluid coupling without suffering from fluid interference.
2Ease of operation
If conventional magnetic rings are used in reciprocating engines, then magnetic signals can be transmitted, but precision is lost due to temperature and vibration effects
Solution Approach 1:
The patent replaces conventional permanent magnetic rings with electronic sensors (Hall effect sensors or magnetoresistive sensors) that detect magnetic field changes. These electronic systems are less sensitive to temperature and vibration effects compared to permanent magnets, maintaining signal precision in harsh engine environments.
Solution Approach 2:
The patent uses magnetic field strength as a variable parameter that changes with piston position. By measuring changes in magnetic field intensity rather than relying on fixed magnetic ring properties, the system achieves precise position detection despite temperature and vibration variations.
3Measurement precision
If magnets are embedded in piston and cylinder, then precise position detection is achieved, but device complexity increases
Solution Approach 1:
The patent extracts the magnetic field generation function from complex embedded magnet structures and implements it through simpler means - either by embedding fewer magnets strategically or by using the engine's existing magnetic components (such as the alternator rotor or starter motor) as the magnetic source. This reduces manufacturing complexity while maintaining detection precision.
4Strength
If magnetic coupling is used through fluid, then wear-free operation is achieved, but signal loss occurs due to fluid interference
Solution Approach 1:
The patent uses a magnetic field as an intermediary that can penetrate the fluid coupling between piston and cylinder. This allows contactless signal transmission through the fluid-filled gap, maintaining wear-free operation while overcoming signal attenuation by using high-strength magnets or sensitive electronic sensors to detect field changes.
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 device achieves high accuracy and durability, insensitive to environmental factors, allowing integration into electric motors without protective housings, and achieving resolutions comparable to optical systems, with reduced material costs and improved stability against interference.
Implementation Method 1
A magnet is embedded in the piston and generates a magnetic field that extends through the piston into the fluid coupling
Implementation Method 2
contactless magnetic signalling through fluid coupling
Data Source
Figure 1~2
Figure 3
AI summary
The invention relates to a magnetic signalling device (1) for measuring the movement and/or position of a rotating component (3), as well as to this rotating component (3). At least one magnetic track extending along the circumference in the form of a magnetisable hard magnetic layer (5 to 12) of a rare earth magnetic material deposited directly on the carrier from a gas phase, is applied to an annular or disc-shaped carrier (13) for connecting the component (3). The carrier (13) consists of a material with higher ductility than that of the hard magnetic layer (5 to 12).