Accelerometer Magnet Fixation with Metallic Insert for Stable Flux
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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 stability, reducing temperature-induced inaccuracies.
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 which affects 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 provides a stable mounting surface for the magnet while being insensitive to temperature changes, thereby isolating the magnet from thermal effects that would otherwise be transmitted through the adhesive to affect scale factor accuracy.
Solution Approach 2:
The invention changes the material parameter of the mounting interface from temperature-sensitive adhesive to temperature-insensitive metallic insert. This parameter change ensures that the physical and magnetic properties of the insert remain stable across temperature variations, preventing changes in magnetic flux and scale factor that would occur with adhesive-based mounting.
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 permeability
Solution Approach 1:
The metallic insert acts as an intermediary that decouples the magnet from the housing, providing a stable magnetic path that is not affected by temperature-induced adhesive deformation. This intermediary component ensures consistent magnetic flux permeability while still allowing for practical assembly through the provision of a stable mounting interface.
3Measurement precision
If a metallic insert is added between the magnet and housing, then temperature stability and magnetic flux consistency are improved, but device complexity increases
Solution Approach 1:
Rather than redesigning the entire accelerometer structure, the invention applies a localized solution by inserting a metallic component only at the critical interface between the magnet and housing. This local modification targets the specific source of temperature-related errors without requiring comprehensive system redesign, thereby minimizing the increase in overall device complexity.
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 consistent magnetic flux and reduces strain, enhancing the accuracy and reliability of accelerometer measurements.
Implementation Method 1
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 be shaped to reduced localized saturation of magnetic flux along the surface of the magnet and/or may reduce circumferential and/or radial strain on the magnet
Data Source
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.