Acceleration Sensor Core Unit Base Board Deflection Control
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Solution Overview
Problem
Existing acceleration sensor core units face challenges in maintaining detection accuracy due to deflection of the base board, which affects the precision of vibration acceleration measurement, especially at high frequencies.
Innovation Solution
The implementation of a base board reinforced by a first and second metallic plate fixed via spacers to suppress deflection, ensuring the base board's stability and parallelism, allowing for accurate detection of vibration acceleration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a simple base board structure is used, then ease of manufacture is improved, but measurement precision deteriorates due to base board deflection
Solution Approach 1:
The patent applies composite material structure by combining the base board with reinforcing plates to create a hybrid structure. The reinforcing plates are made of different material (e.g., metal or ceramic) with higher rigidity than the base board material (e.g., PCB), forming a composite structure that enhances overall stiffness while maintaining manufacturability through standardized assembly processes
Solution Approach 2:
The base board structure is segmented into multiple functional components: the base board itself, separate reinforcing plates, and spacing members. This segmentation allows each component to be manufactured independently using appropriate processes, then assembled together to achieve the required rigidity without compromising the ease of manufacture of individual parts
2Measurement precision
If reinforcing structures are added to suppress deflection, then measurement precision is improved, but device complexity increases
Solution Approach 1:
Rather than making the entire base board structure uniformly complex, the patent applies reinforcing plates only at specific locations where deflection occurs most significantly. The spacing members are positioned strategically to provide localized support, thereby improving measurement precision without unnecessarily increasing overall device complexity
Solution Approach 2:
The patent addresses the two-dimensional base board deflection problem by introducing a third dimension - vertical spacing members that create separation between the base board and reinforcing plates. This dimensional approach allows the reinforcing structure to counteract deflection forces effectively while maintaining a compact overall design
3Measurement precision
If the base board is made more rigid, then measurement precision is improved, but thermal expansion issues arise
Solution Approach 1:
The composite structure of base board plus reinforcing plates allows selection of materials with complementary thermal properties. The base board can be made of a material with low thermal expansion coefficient, while the reinforcing plates provide the necessary rigidity, together forming a structure that is both dimensionally stable and rigid without suffering from severe thermal expansion issues
Solution Approach 2:
The spacing members act as intermediaries between the base board and reinforcing plates, providing a buffer that accommodates differential thermal expansion between the two materials. This intermediary element allows the rigid reinforcing structure to be attached to the base board without creating thermal stress concentration points
Data Source
AI summary
An acceleration sensor core unit 1 includes a circuit board 3 and metallic plates 4, 5. The circuit board 3 is made of an epoxy resin, and an acceleration sensor 11 for detecting vibration acceleration in an arrow 105 direction is mounted thereon. The circuit board 3 is sandwiched between the metallic plates 4, 5. Ring-shaped metallic spacers 7a to 7c and ring-shaped metallic spacers 8a to 8c are respectively interposed between the circuit board 3 and the metallic plate 4 and between the circuit board 3 and the metallic plate 5. The circuit board 3 is screwed to each of the metallic plates 4, 5 at three positions. Thus, it is possible to reliably fix the circuit board 3 to the metallic plates 4, 5 with a small attachment space. In this way, rigidity as the acceleration sensor core unit 1 can be secured.