Temperature Sensor Low Young's Modulus Layer Thermal Stress
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Solution Overview
Problem
The existing temperature sensor with a ceramic tablet and glass sealing body, having different linear expansion coefficients, experiences thermal stress due to temperature changes, which can lead to damage and inefficiency.
Innovation Solution
A temperature sensor design incorporating a low Young's modulus layer within the glass sealing body, made of materials like lead glass, to connect the ceramic tablet and glass sealing body, reducing thermal stress by increasing the deformation area and matching the linear expansion coefficients of the materials involved.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a ceramic tablet and glass sealing body with different linear expansion coefficients are joined together, then the temperature sensor can be assembled with existing materials, but thermal stress is generated between the tablet and glass sealing body when temperature changes
Solution Approach 1:
A low Young's modulus layer is introduced as an intermediary between the ceramic tablet and glass sealing body. This intermediate layer has lower Young's modulus than both the tablet and sealing body, allowing it to deform and absorb thermal stress, thereby preventing direct stress transmission between the ceramic tablet and glass sealing body while maintaining their structural integrity.
Solution Approach 2:
The Young's modulus parameter of the intermediate layer is specifically controlled to be lower than both the ceramic tablet and glass sealing body. This parameter change enables the intermediate layer to undergo greater deformation under thermal stress, effectively dissipating stress concentrations that would otherwise occur at the junction between materials with different thermal expansion coefficients.
2Adaptability or versatility
If materials with different linear expansion coefficients are used for the ceramic tablet and glass sealing body, then material selection flexibility is improved, but thermal shock resistance deteriorates
Solution Approach 1:
The low Young's modulus layer serves as a stress-absorbing intermediary that decouples the thermal stress interaction between the ceramic tablet and glass sealing body. This allows each component to maintain its optimal material properties for its specific function while the intermediate layer handles the thermal mismatch, thereby improving thermal shock resistance without compromising material selection flexibility.
3Device complexity
If the glass sealing body is made from a single material, then manufacturing simplicity is maintained, but the ability to suppress thermal stress is reduced
Solution Approach 1:
The glass sealing body is segmented into two distinct parts: a sealing portion and a low Young's modulus layer. The sealing portion maintains its traditional sealing function with appropriate mechanical strength, while the low Young's modulus layer is specifically designed to suppress thermal stress. This segmentation allows each part to perform its specialized function optimally without compromising overall manufacturing feasibility.
Solution Approach 2:
Different regions of the glass sealing body are assigned different material properties: the sealing portion has higher Young's modulus for structural integrity and sealing performance, while the low Young's modulus layer has lower Young's modulus for thermal stress suppression. This local differentiation of material quality enables the sealing body to simultaneously achieve both sealing reliability and thermal stress resistance.
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 low Young's modulus layer effectively reduces thermal stress between the ceramic tablet and glass sealing body, enhancing the sensor's thermal shock resistance and operational stability while maintaining structural integrity.
Implementation Method 1
the ceramic tablet and the glass sealing body, which are two parts having different linear expansion coefficients, are joined to each other. Accordingly, in the temperature sensor, when temperature changes, thermal stress might be generated between the tablet and the glass sealing body
Implementation Method 2
a low Young's modulus layer provided in the glass sealing body, made of a material having lower low Young's modulus than that of a material forming the sealing portion, and at least partially connecting the sealing portion and the interface of the tablet
Data Source
AI summary
A temperature sensor has a thermosensitive element that detects temperature, a pair of element electrode wires electrically connected to the thermosensitive element, and a glass sealing body that has a sealing portion covering the thermosensitive element and a part of the element electrode wires. Further, the temperature sensor has a tablet that has an interface and a pair of insertion holes into which the element electrode wires are inserted, the tablet being joined to the glass sealing body through the interface. Further, the temperature sensor has a low Young's modulus layer provided in the glass sealing body, made of a material having lower low Young's modulus than that of a material forming the sealing portion, and at least partially connecting the sealing portion and the interface of the tablet.