Ceramic Sensor Module Sealing via Integrated O-Ring Groove
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Solution Overview
Problem
Existing physical quantity measuring sensors, particularly pressure sensors with ceramic sensor modules, face challenges in securely attaching ceramic modules to metallic joints without welding, leading to fluid leakage and increased manufacturing costs due to complex O-ring holding structures and complicated electronic component attachment processes.
Innovation Solution
A simplified structure where a ceramic sensor module with a diaphragm and cylindrical portion is integrated with a joint's projection, using an O-ring interposed between the sensor-module flat portion and joint flat portion, which functions as a cross-sectionally square C-shaped groove, and a retaining member to prevent displacement, allowing direct attachment of electronic components to the sensor module, eliminating the need for flexible circuit boards and reducing assembly complexity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a ceramic sensor module is used, then the sensor module cannot be welded to the metallic joint, but this causes fluid leakage between the sensor module and joint
Solution Approach 1:
An O-ring is introduced as an intermediary sealing element between the ceramic sensor module and metallic joint. The O-ring fits into a groove structure that is integrally formed with the joint projection, mediating the connection between dissimilar materials (ceramic and metal) while preventing fluid leakage.
2Reliability
If a C-shaped groove is separately machined to hold the O-ring, then the O-ring can be securely held, but the manufacturing cost increases
Solution Approach 1:
The O-ring holding groove is merged with the joint projection structure itself, forming an integrally formed groove. This eliminates the need for separate machining operations to create the groove, reducing manufacturing steps and costs while maintaining secure O-ring retention.
3Ease of manufacture
If the groove width is increased to fit the O-ring, then the O-ring can be fitted, but the projection width decreases making the tip end likely to break
Solution Approach 1:
The groove is positioned in the axial direction of the projection rather than only in the radial direction. This axial positioning allows the groove to be located away from the tip end, maintaining the projection's structural strength while still providing adequate space for the O-ring in the radial dimension.
4Strength
If the projection is lengthened to prevent tip breakage, then the projection strength is maintained, but the sensor length increases
Solution Approach 1:
The groove is positioned axially away from the tip end rather than requiring a longer projection with a groove near the tip. This allows the projection to maintain its original length while the groove's axial displacement prevents tip breakage by reducing stress concentration.
5Adaptability or versatility
If electronic components are mounted on a flexible circuit board, then the components can be connected to the sensor module, but the assembly process becomes complicated
Solution Approach 1:
The electronic component is merged directly with the sensor module structure, eliminating the need for a separate flexible circuit board. This integration simplifies the assembly process by reducing the number of components and connection steps while maintaining electrical connectivity functionality.
Data Source
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AI summary
A physical quantity measuring sensor includes: a joint (1) having a projection (15); a ceramic sensor module (2) including a diaphragm (21) and a cylindrical portion (22) integrated with the diaphragm (21) and provided to the projection (15); and an O-ring (7) interposed between a sensor-module flat portion (22A) extending in a direction orthogonal to an axial direction of the cylindrical portion (22) and a joint flat portion (15A) extending in a direction orthogonal to an axial direction of the projection (15).