Magnetoelastic Torque Transducer Noise Reduction
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Solution Overview
Problem
Existing torque sensing devices suffer from rotation noise due to physical irregularities and variations in magnetic field strength and direction, which affect the accuracy of torque measurement.
Innovation Solution
A method and system for magnetizing a torque transducer that adjusts the magnetization field direction to eliminate rotation noise by creating radially distinct, oppositely polarized magnetically conditioned regions on a rotatable shaft or disk, using permanent magnets and magnetic field sensors to measure and compensate for irregularities, ensuring accurate torque measurement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a magnetoelastically active region is used for torque sensing, then torque measurement capability is provided, but rotation noise is generated due to physical irregularities and magnetic field variations
Solution Approach 1:
The magnetoelastically active region is divided into multiple magnetically conditioned regions with distinct magnetic polarizations. Each region is magnetized in a specific direction (e.g., circumferential, radial, axial) to create segmented magnetic fields that collectively cancel rotation noise while maintaining torque sensing capability.
Solution Approach 2:
Different regions of the magnetoelastically active material are given different magnetic properties through selective magnetization. Each local region has a specific magnetic polarization direction tailored to its position, creating local quality variations that eliminate rotation noise while preserving overall torque measurement function.
2Measurement precision
If magnetically conditioned regions are created to eliminate rotation noise, then measurement accuracy is improved, but device complexity increases
Solution Approach 1:
The magnetically conditioned regions are created during the manufacturing process through preliminary magnetization of the magnetoelastically active material. By pre-establishing the desired magnetic polarization patterns before the device is put into service, the complex magnetization process is performed once during fabrication rather than requiring ongoing complexity during operation.
3Object-generated harmful factors
If multiple magnetically conditioned regions are used to cancel rotation noise, then noise elimination is achieved, but manufacturing complexity increases
Solution Approach 1:
Multiple magnetization operations that would otherwise be performed separately are merged into a single integrated magnetization process. By combining the creation of multiple magnetically conditioned regions with distinct polarizations into one coordinated magnetization step, the manufacturing process becomes more efficient and less complex.
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 effectively eliminates rotation noise, providing accurate and reliable torque measurement by compensating for physical irregularities and variations in the magnetization of the torque transducer, resulting in a magnetoelastic torque transducer with minimal noise and improved accuracy.
Implementation Method 1
the magnetoelastically active region includes one or more magnetically conditioned regions that are magnetically polarized in a circumferential direction and possess sufficient magnetic anisotropy to return the magnetization in the region, following the application of torque to the shaft, to the circumferential direction when the applied torque is reduced to zero. When a torque is applied to the shaft, the circumferential magnetic orientations of the magnetically conditioned regions reorient such that they exhibit helical magnetic orientations having both circumferential and axial components.
Implementation Method 2
Magnetic field sensors mounted proximate to the magnetically conditioned regions, without contacting the regions, are configured to sense only the axial components of magnetic fields produced by the regions.
Data Source
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AI summary
A system and method for creating one or more magnetically conditioned regions on a rotatable shaft or disk-shaped torque sensing element, wherein rotation noise produced by the element due to magnetic field variations is substantially negated, and a system and method for creating one or more magnetically conditioned regions on a rotatable shaft or disk-shaped element to allow the element to function as part of a rotational speed or rotational position sensing device.