Magnetostrictive Torque Sensor with Encapsulated Magnet and Die
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing magnetic field sensors struggle to accurately measure torque applied to a shaft, particularly in applications requiring precise detection of force values.
Innovation Solution
A sensor system comprising a supporting member, a permanent magnet, and a sensor die with sensing elements and processing circuitry, which generates signals in response to a pattern of magnetic flux density modulated by force applied to a shaft, and maps these signals to force values for output.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Difficulty of detecting and measuring
If magnetic field sensors are used to detect torque applied to a shaft, then the ability to detect magnetic field patterns is improved, but the measurement precision of force values deteriorates
Solution Approach 1:
The sensor system segments the measurement function into multiple specialized sensing elements (Hall effect sensors, magnetoresistive sensors, or magnetic field gradient sensors) that detect different aspects of the magnetic field pattern. Each sensing element is optimized for detecting specific magnetic field characteristics, and the processing circuitry integrates these segmented measurements to reconstruct the complete force information with high precision.
Solution Approach 2:
A ferromagnetic shaft or ferromagnetic target acts as an intermediary between the applied force and the magnetic field sensors. The ferromagnetic material concentrates and modulates the magnetic field in response to applied force, creating an enhanced magnetic field pattern that the sensors can detect with higher precision. This intermediary transforms mechanical force into a detectable magnetic field modulation.
2Device complexity
If a permanent magnet and sensor die are encapsulated together, then the structural integration is improved, but the manufacturing complexity worsens
Solution Approach 1:
The permanent magnet and sensor die are merged into a single encapsulated unit using a molding process. The encapsulating material simultaneously bonds both components together and provides environmental protection, creating a structurally integrated sensor assembly that functions as a single manufacturable unit.
Solution Approach 2:
The encapsulating material undergoes a parameter change from liquid or semi-liquid state to solid state through curing or cooling. This phase transition allows the material to flow around and conform to the permanent magnet and sensor die during molding, then solidifies to provide strong mechanical bonding and structural integration of the components.
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 sensor system effectively measures torque applied to a shaft by accurately mapping signal patterns to force values, enhancing precision and reliability in applications such as automotive control systems.
Implementation Method 1
a magnetic field sensor that includes a magnetic field sensing element, or transducer... the plurality of sensing elements being arranged to generate one or more signals in response to a pattern of magnetic flux density that is produced by the permanent magnet and modulated by an application of force to a shaft
Data Source
AI summary
A sensor, comprising: a supporting member; a permanent magnet that is coupled to the supporting member; and a sensor die having a plurality of sensing elements and processing circuitry formed thereon, the plurality of sensing elements being arranged to generate one or more signals in response to a pattern of magnetic flux density that is produced by the permanent magnet and modulated by an application of force to a shaft, the processing circuitry being configured to map the one or more signals to a value of a force applied to the shaft, and output an indication of the value of the force, wherein the permanent magnet and the sensor die are encapsulated in an encapsulating material, the encapsulating material being used to form a package of the sensor.