Sectional Magnetic Encoding for Shaft Torque Measurement
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Solution Overview
Problem
Conventional methods for measuring forces and shaft operating parameters on large diameter shafts, such as those in wind turbines, face challenges due to high power requirements, complex encoding schemes, and limited accuracy, making them costly and impractical for large diameter applications.
Innovation Solution
The use of sectional magnetic encoding on the shaft, where magnetically encoded regions are created by applying current through electrodes to form alternating polarized tracks, allowing for the detection of torque, bending moments, and rotational parameters without the need for continuous circumferential encoding, thus reducing the power and complexity associated with large diameter shafts.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional magnetic encoding is applied to large diameter shafts, then measurement capability is achieved, but power requirements become excessively high
Solution Approach 1:
The shaft circumference is divided into discrete magnetic tracks spaced at specific intervals (e.g., 90 degrees apart). Instead of encoding the entire circumference, only specific angular positions are magnetically encoded, creating segmented measurement zones that reduce the total power required while maintaining measurement capability through multiple discrete tracks.
Solution Approach 2:
Magnetic encoding is applied locally at specific angular positions around the shaft circumference rather than uniformly across the entire circumference. Each local track serves a specific measurement function, and the non-uniform distribution of encoded regions reduces overall energy consumption while preserving measurement precision at critical locations.
2Measurement precision
If continuous circumferential magnetic encoding is applied to large diameter shafts, then complete measurement coverage is achieved, but system complexity increases
Solution Approach 1:
The continuous circumferential encoding is segmented into discrete tracks at specific angular intervals. This segmentation simplifies the encoding scheme by eliminating the need for continuous encoding while maintaining measurement coverage through strategically positioned tracks that capture essential shaft parameters.
Solution Approach 2:
The discrete magnetic tracks are designed to serve multiple measurement functions simultaneously. The same track configuration enables measurement of rotational position, speed, and acceleration, reducing system complexity by eliminating the need for separate encoding schemes for different measurement types.
3Measurement precision
If conventional magnetic encoding is used on large diameter shafts, then measurement is possible, but cost increases significantly
Solution Approach 1:
By segmenting the magnetic encoding into discrete tracks rather than continuous circumferential encoding, the amount of magnetic material and encoding processing required is significantly reduced. This segmentation directly lowers manufacturing costs while preserving measurement capability through the use of multiple discrete tracks.
Solution Approach 2:
Instead of applying magnetic encoding to the entire shaft circumference, the invention uses partial action by encoding only specific angular positions. This partial encoding approach reduces material costs, processing costs, and system complexity while maintaining sufficient measurement coverage for large diameter shafts.
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 approach enables accurate and cost-effective measurement of forces and rotational parameters on large diameter shafts, improving operational efficiency and reducing the complexity of sensor systems, allowing for continuous torque readout independent of shaft diameter.
Implementation Method 1
magnetically encoded regions are created by applying current through electrodes to form alternating polarized tracks
Implementation Method 2
a first fixed magnetic field sensor for detecting magnetic fields in the force-sensitive regions
Data Source
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AI summary
Magnetically encoded shafts for use in detecting forces exerted on the shaft (271) during operation. magnetically encoded regions (272) arranged in tracks (272) or bands, encircle the shaft (271) and are formed within or affixed to the shaft (271). The magnetically encoded regions (272) define force-sensitive regions (272) therebetween. Magnetic fields surround the force-sensitive regions (272) and are altered by force vectors passing through the force sensitive region (509). These magnetic fields are sensed by magnetic field sensors (352) to determine various shaft (271) parameters including, for example: shaft (271) rotational speed, shaft (271) rotational position, and forces exerted on the shaft (271), e.g., torque, bending forces, stress forces and strain forces. To provide continuous detection of shaft (271) operational parameters and forces, dead zones between magnetically encoded regions (272) are aligned with force sensitive regions (509) associated with magnetically encoded regions (272) in other bands.