Segmented Thermocouple Sheath for Vibration Resistance
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Solution Overview
Problem
Existing temperature sensors for high-temperature applications, such as exhaust gas measurement in motor vehicles, face challenges with mechanical and thermal stresses, leading to malfunctions and complex manufacturing processes, particularly due to the use of small-diameter insulating sheaths that require additional reinforcement and manual operations.
Innovation Solution
A temperature sensor design featuring a large-diameter insulating sheath without the need for reinforcing tubes, with a thermocouple configuration that includes a narrowed end portion and a cap structure to enhance robustness and simplify manufacturing, allowing for precise and rapid temperature measurement while withstanding severe vibrations and high temperatures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If a small-diameter insulating sheath (3-4 mm) is used, then the response time is improved, but the mechanical strength and vibration resistance deteriorate
Solution Approach 1:
The insulating sheath is segmented into two distinct zones: a first zone with small diameter (3-4 mm) for optimized response time, and a second zone with large diameter (6-10 mm) for enhanced mechanical strength. This segmentation allows each zone to fulfill its specific functional requirement independently, resolving the contradiction between response time and mechanical strength.
2Loss of time
If a small-diameter insulating sheath (3-4 mm) is used, then the response time is improved, but the device complexity increases due to requiring reinforcing tubes
Solution Approach 1:
The insulating sheath is segmented into two distinct zones: a first zone with small diameter (3-4 mm) for optimized response time, and a second zone with large diameter (6-10 mm) for enhanced mechanical strength. This segmentation allows each zone to fulfill its specific functional requirement independently, resolving the contradiction between response time and mechanical strength.
Solution Approach 2:
The patent merges the functions of the insulating sheath and reinforcing tube into a single integrated structure. The second zone of the insulating sheath itself provides the mechanical reinforcement that would otherwise require a separate tube, thereby reducing device complexity while maintaining vibration resistance.
3Strength
If a large-diameter insulating sheath (6 mm) is used, then the vibration resistance is improved, but the response time deteriorates
Solution Approach 1:
The insulating sheath is segmented into two distinct zones: a first zone with small diameter (3-4 mm) for optimized response time, and a second zone with large diameter (6-10 mm) for enhanced mechanical strength. This segmentation allows each zone to fulfill its specific functional requirement independently, resolving the contradiction between response time and mechanical strength.
4Strength
If a large-diameter insulating sheath (6 mm) is used, then the vibration resistance is improved, but the manufacturing complexity increases due to requiring shrinkage operations
Solution Approach 1:
The insulating sheath is pre-formed with a stepped configuration during manufacturing, with the first zone having small diameter and the second zone having large diameter. This preliminary formation eliminates the need for post-assembly shrinkage operations, simplifying the manufacturing process while maintaining vibration 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 solution provides a robust, precise, and rapidly responding temperature sensor that is simpler to implement, capable of measuring temperatures above 900°C with improved durability and reduced manufacturing complexity compared to prior art.
Implementation Method 1
The measuring principle of thermocouples is based on the Seebeck effect which results in a potential difference between two wires of different metals when they are subjected to a temperature difference.
Data Source
Figure 1~2
Figure 3
AI summary
The invention relates to a temperature sensor (1) for a motor vehicle and a method for manufacturing same. The temperature sensor (1) comprises: - a thermocouple (2) that has two metal wires (3) which are welded together at a first end (4) forming a hot junction for measuring a temperature T1 in the motor vehicle, the two metal wires (3) each having a second end that is electrically connected to an electric connector; and - a first thermocouple section (5) in which an insulating sheath (7) surrounds the metal wires (3) of the thermocouple (2), the two metal wires (3) in the first thermocouple section (5) being separated from each other by a distance D. According to the invention, the temperature sensor (1) comprises: - a second thermocouple section (6) which is not covered by the insulating sheath (7), extends from the first end (4) of the metal wires (3) of the thermocouple (2) to a front end (8) of the insulating sheath (7), and has a constricted end portion (9) in which the two metal wires (3) in the second thermocouple section (6) are separated from each other by a distance d that is shorter than the distance D separating the metal wires (3) in the first thermocouple section (5); and - a cap (10) which surrounds the second thermocouple section (6) in order to protect the hot junction.