Magnetostrictive Sensor Torque Detection with Local Composition Gradients
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Solution Overview
Problem
Existing magnetostrictive sensors face challenges in achieving high sensitivity while maintaining efficient manufacturing processes, as strict control of chemical composition is required to optimize magnetostriction constant and magnetic permeability, limiting flexibility in material composition variations.
Innovation Solution
A magnetostrictive sensor design featuring a magnetostrictive portion with varying concentrations of elements, arranged in specific patterns across the surface, allowing for internal stress generation without strict chemical composition control, thereby enhancing sensitivity and manufacturing efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the chemical composition of the magnetostrictive material is strictly controlled to optimize magnetostriction constant and magnetic permeability, then sensitivity of the magnetostrictive sensor is improved, but manufacturing complexity and cost increase
Solution Approach 1:
The magnetostrictive material is designed with non-uniform chemical composition, where different regions contain different concentrations of alloying elements (Ni, Co, Mo, Mn, Cr). This local variation in composition creates corresponding variations in magnetostriction constant and magnetic permeability across the material, allowing the sensor to achieve high sensitivity without requiring strict overall compositional control. The non-uniform structure enables different areas to contribute differently to the sensing function.
Solution Approach 2:
The invention changes the chemical composition parameters of the magnetostrictive material by intentionally introducing variations in element concentrations rather than maintaining uniform composition. By allowing the magnetostriction constant and magnetic permeability to vary spatially through compositional changes, the sensor achieves enhanced sensitivity while simplifying manufacturing requirements, as exact compositional uniformity is no longer necessary.
2Measurement precision
If the chemical composition is adjusted to increase magnetostriction constant and magnetic permeability, then sensitivity increases, but manufacturing precision requirements become more stringent
Solution Approach 1:
Rather than requiring precise uniform composition throughout the magnetostrictive material, the invention employs local quality variations where different regions have different element concentrations. This approach transforms the manufacturing challenge from achieving uniform precision to allowing controlled local variations, thereby reducing overall manufacturing precision requirements while maintaining or enhancing sensitivity.
Solution Approach 2:
The magnetostrictive material is designed as a composite with spatially varying composition, combining multiple alloying elements (Ni, Co, Mo, Mn, Cr) in non-uniform distributions. This composite structure with graded or zoned composition enables the material to achieve desired magnetic and magnetostrictive properties without requiring strict compositional control, as the varied composition itself is the functional feature.
3Ease of manufacture
If uniform chemical composition is used throughout the magnetostrictive portion, then manufacturing is simplified, but sensitivity is reduced due to lack of internal stress variations
Solution Approach 1:
The invention introduces local quality variations in the form of non-uniform chemical composition to generate internal stress variations throughout the magnetostrictive material. These local compositional differences create corresponding variations in magnetostriction constant and magnetic permeability, which enhance sensitivity while still allowing for relatively simple manufacturing processes that do not require complex compositional control.
Solution Approach 2:
By changing the composition parameters from uniform to non-uniform distribution, the invention simultaneously achieves enhanced sensitivity through internal stress variations and maintains manufacturing simplicity. The key is that the non-uniform composition can be achieved through standard manufacturing variations rather than requiring additional complex processing steps.
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 design achieves increased sensitivity and simplified manufacturing by allowing deviations in chemical composition, while maintaining effective torque detection capabilities.
Implementation Method 1
a magnetostrictive portion containing a magnetostrictive material is formed on an outer peripheral surface of a base material on which a torque or a load acts... The above-described structure of the magnetostrictive sensor causes a magnetic permeability of the magnetostrictive material of the magnetostrictive portion to change when a force acts on the base material
Data Source
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AI summary
A configuration that enables efficient manufacturing of magnetostrictive sensors with high sensitivity can be obtained. A torque sensor 1 includes a magnetic structure 20 including a base material 21 and a magnetostrictive film 2. In the magnetic structure 20, suppose a cross section orthogonal to an axis A is a first cross section and a cross section orthogonal to the first cross section and passing through the axis A is a second cross section, the magnetostrictive film 2 satisfies at least one of requirements (A), (B), and (C): (A) in the first cross section, portions having different concentrations of at least one element are arranged clockwise about the axis A, (B) in the first cross section, portions having different concentrations of the at least one element are arranged in the thickness direction of the magnetostrictive film 2, and (C) in the second cross section, the portions having different concentrations of the at least one element are arranged along the axis A.