Hermetic Pressure Sensor with Annular Wave-like Section
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Solution Overview
Problem
Existing hermetic pressure sensors for automotive applications are prone to malfunction due to non-gas-tight housings, copper-sulfur corrosion, and vulnerability to harsh environmental conditions, requiring a more robust and reliable solution with reduced sensitivity to point forces and dynamic pressures.
Innovation Solution
A hermetic pressure sensor design featuring a disk-shaped housing with a membrane section and a second housing structure connected by an annular weld, using non-conductive sealing materials for electrical pins and microfused silicon strain gages, along with an annular wave-like section to distribute forces and reduce sensitivity to external pressures, and a printed circuit board for signal processing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a glass base sensor chip is used with glass to metal seal, then hermetic sealing is achieved, but the sensor becomes vulnerable to cracking under pressure peaks and dynamic forces
Solution Approach 1:
The housing is divided into two separate hermetic housing structures (first and second housing structures) that are hermetically connected to each other. The sensor chip is enclosed in the first housing structure while the electronics are enclosed in the second housing structure. This segmentation isolates the fragile sensor chip from direct exposure to pressure peaks and dynamic forces, preventing cracking while maintaining hermetic sealing.
Solution Approach 2:
The two hermetic housing structures act as intermediary protective enclosures between the sensor chip and the harsh external environment. The first housing structure protects the sensor chip, while the second housing structure protects the electronics, and their hermetic connection maintains overall sealing without exposing the sensor chip to damaging forces.
2Volume of moving object
If the sensor housing is made smaller for transmission applications, then space requirements are reduced, but hermetic sealing becomes more difficult to achieve
Solution Approach 1:
The sensor chip is nested within the first hermetic housing structure, which is then nested within or connected to the second hermetic housing structure. This nested arrangement allows the compact enclosure of multiple components (sensor chip, electronics, and interconnections) in a small overall housing volume while maintaining hermetic sealing through the nested housing structures.
3Ease of operation
If electrical connection pins pass through the housing with hermetic sealing material, then electrical connections are established, but the housing integrity and hermetic seal may be compromised
Solution Approach 1:
The electrical connection pins are extracted through openings in the second housing structure and affixed with non-conductive hermetic sealing material. This extraction method allows electrical connections to be established while the non-conductive hermetic sealing material maintains the housing integrity and hermetic seal by filling and sealing the openings through which the pins pass.
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 solution provides a robust, cost-effective, and airtight pressure sensor capable of withstanding harsh conditions and temperature variations, with reduced sensitivity to point and uniform forces, ensuring accurate pressure measurement in automotive applications.
Implementation Method 1
The strain sensing element may be a micro fused silicon strain gage
Implementation Method 2
The hermetic housing also includes a second housing structure which is hermetically connected to the first housing structure
Data Source
AI summary
A hermetic pressure sensor for measuring a fluid pressure includes a hermetic housing, formed of a first housing structure with a membrane section, a second housing structure hermetically connected to the first structure, and one or more strain sensing elements attached to the membrane section. The second housing structure includes openings for one or more electrical pins while a non-conductive hermetic seal holds the electrical pins in place. The pressure sensor measures the pressure of fluid entering the housing while also providing a hermetic seal.