Accelerometer Magnet Fixation Using a Metallic Flux Insert
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Solution Overview
Problem
Adhesives used to secure magnets in accelerometers change shape with temperature, affecting magnetic flux and scale factor, thereby reducing accuracy.
Innovation Solution
Incorporating a metallic insert between the magnet and non-moving member to enhance magnetic flux permeability and maintain shape consistency, reducing temperature-induced variability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If adhesives are used to secure the magnet to the non-moving member, then the magnet can be fixed in place, but the adhesive changes shape with temperature changes, affecting magnetic flux and scale factor accuracy
Solution Approach 1:
A metallic insert is introduced as an intermediary component between the magnet and the non-moving member. This insert serves as a mediator that maintains magnetic flux pathways while providing mechanical support, eliminating the need for adhesives that deform with temperature changes.
Solution Approach 2:
The invention changes the material parameter from adhesive (which has poor thermal stability and magnetic flux properties) to a metallic insert with superior thermal stability and enhanced magnetic flux permeability, thereby maintaining accuracy across temperature variations.
2Ease of manufacture
If adhesives are used to secure the magnet, then assembly is simplified, but temperature changes cause adhesive deformation that alters magnetic flux and reduces accelerometer accuracy
Solution Approach 1:
The metallic insert acts as a stable intermediary that maintains consistent physical and magnetic properties across temperature ranges, replacing the thermally unstable adhesive while preserving the assembly function.
Solution Approach 2:
The solution employs a composite structure combining the metallic insert with the existing accelerometer components, creating a hybrid assembly that leverages the superior thermal and magnetic properties of metal while maintaining the overall device architecture.
3Measurement precision
If a metallic insert is added between the magnet and non-moving member, then magnetic flux permeability and temperature stability are improved, but device complexity increases
Solution Approach 1:
The metallic insert is placed locally at the critical interface between the magnet and non-moving member, providing enhanced magnetic flux permeability and thermal stability only where needed, rather than redesigning the entire device structure.
Solution Approach 2:
The insertion of a separate metallic component segments the magnetic assembly into distinct functional zones, allowing independent optimization of magnetic flux pathways and mechanical support without affecting other device 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 metallic insert maintains magnetic flux balance and accuracy by distributing flux and compensating for temperature changes, enhancing the accelerometer's precision and reliability.
Implementation Method 1
The shim may be formed from a metallic alloy. The shim may exhibit increased permeability of magnetic flux (e.g., compared to an adhesive) between the non-moving member and the magnet
Implementation Method 2
The shim may maintain a substantially similar shape regardless of the internal temperature of the accelerometer system
Implementation Method 3
processing circuitry configured to: cause a current to flow through the coil to apply a Lorentz force to the proof mass
Data Source
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AI summary
An accelerometer system comprising: a housing; a magnet disposed within the housing and extending along a longitudinal axis from a first end to a second end; and a metallic insert disposed between the first end of the magnet and a surface of the housing, wherein a first surface of the metallic insert is configured to contact the first end of the magnet, and wherein a second surface of the metallic insert is configured to contact the surface of the housing.