Hard Magnetic Encoder Layer for High-Temperature Position Sensing
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Solution Overview
Problem
Current magnetic rotary encoders are limited by precision, speed, operating temperature, and service life due to polymer-based composite layers, which are sensitive to oils and greases, and cannot meet the increasing demands of high-performance applications.
Innovation Solution
A magnetic signaling device with a hard magnetic layer composed of NdFeB and/or Co5Sm, applied directly onto a support element via gas phase deposition methods, such as hollow cathode gas flow sputtering or PVD, without a polymer matrix, achieving high adhesion, resistance to oils and greases, and precise magnetization.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If polymer-based composite magnetic layers are used in rotary encoders, then manufacturing cost is reduced and ease of manufacture is improved, but service life is limited due to sensitivity to oils and greases, and operating temperature is restricted
Solution Approach 1:
The patent changes the fundamental material parameter from polymer-based composite to metal-based hard magnetic layer deposited from gas phase. This material parameter change eliminates sensitivity to oils and greases while maintaining manufacturability through PVD/CVD processes, thereby resolving the contradiction between ease of manufacture and service life
Solution Approach 2:
The patent uses composite structure of metal magnetic layer (NdFeB, CoSm, or Co17Sm2) deposited on a support element, creating a new composite material system that combines the advantages of hard magnetic properties with resistance to environmental factors, thus improving service life while maintaining ease of manufacture
2Ease of manufacture
If polymer-based composite layers are used in magnetic encoders, then manufacturing simplicity is improved, but measurement precision is limited to ±1° and cannot achieve high-resolution measurements
Solution Approach 1:
The patent changes the material composition parameter from polymer composite to metal-based hard magnetic layer, which enables much finer magnetization patterns and higher resolution measurements. The gas phase deposition process allows precise control of layer thickness and magnetic properties, achieving measurement precision beyond the ±1° limitation of polymer-based systems
3Measurement precision
If optical encoders are used with protective housings to compensate for environmental sensitivity, then measurement precision is maintained, but device complexity increases and mounting options are limited
Solution Approach 1:
The patent replaces the optical measuring system with a magnetic measuring system. The magnetic field-based measurement principle is inherently insensitive to environmental factors like dust, moisture, and temperature fluctuations, eliminating the need for complex protective housings and ball bearings while maintaining measurement precision and simplifying the overall device structure
4Measurement precision
If optical encoders are used, then measurement precision can be maintained with protective housings, but mounting options are limited and costs rise disproportionately with shaft diameter
Solution Approach 1:
The patent replaces the optical system with a magnetic system that does not require complex protective housings or additional ball bearings. The magnetic encoder can be mounted directly on the shaft without requiring a free shaft end, providing greater adaptability and versatility across different shaft diameters and mounting configurations while maintaining measurement precision
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 solution provides high precision, robustness, and extended operating temperature up to 250°C, enabling resolutions of up to 18 bits and integration into electric motors without complex housings or bearings, suitable for high-speed and harsh environments.
Implementation Method 1
a hard magnetic layer without polymer content applied to the support element and/or the support structure, wherein the hard magnetic layer is applied by at least one of the methods according to hollow cathode gas flow sputtering and/or hollow cathode sputtering and/or electroplating and/or PVD and/or CVD and/or plasma spraying
Implementation Method 2
the hard magnetic layer has a magnetic structure in the direction of rotation such that, depending on the angle of rotation of the component, the magnetic structure of the hard magnetic layer, for example the magnetic field strength and/or orientation at different heights, can be measured via a sensor
Data Source
Figure 1~2
Figure 3
AI summary
The invention relates to a magnetic signal device (1) for measuring the movement and/or the position of a component of a drive machine, wherein the magnetic signal device has a support structure (13) and a hard magnetic layer (14) applied to the support structure, wherein the hard magnetic layer (14) is applied via hollow cathode flow sputtering and/or electroplating and/or PVD and/or CVD and/or plasma spraying, the hard magnetic layer consists of X mass% NdFeB and/or Co5Sm and/or Co2Sm17 and/or Co5Sm and/or Co2Sm17, and the hard magnetic layer has a magnetic remanence of 0.1 T to 1.3 T in the sensing range thereof.