Oil Temperature Sensor Thermistor Embedding and Resin Molding
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Solution Overview
Problem
Existing oil temperature sensors face issues with thermistor damage and disconnection, leading to decreased temperature detection accuracy due to exposure of the thermistor element during manufacturing and potential contact with equipment.
Innovation Solution
A sensor body design where a thermistor is buried within a resin mold portion, with lead frames having recesses to secure the thermistor and prevent exposure, and the connecting portions are cut after molding to prevent relative movement and damage, ensuring accurate temperature detection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the thermistor is exposed outside the sensor body, then the manufacturing process is simpler, but the thermistor may be damaged or disconnected leading to deteriorated temperature detection accuracy
Solution Approach 1:
The patent embeds the thermistor inside the sensor body housing, nesting it within a protective cavity. The thermistor is positioned inside the housing rather than exposed externally, similar to how nested dolls contain one within another. This protective nesting prevents damage and disconnection while maintaining manufacturing feasibility through integrated molding processes.
Solution Approach 2:
The patent performs preliminary protective action by pre-embedding the thermistor in a protective position within the housing before final assembly. The thermistor is secured in place with mounting structures and protective coverings during the manufacturing process, preventing potential damage before the sensor is put into service.
2Reliability
If the thermistor is embedded in resin mold portion, then the thermistor is protected from damage, but the manufacturing process becomes more complex
Solution Approach 1:
The patent merges the thermistor mounting structure with the housing structure by integrating the resin mold portion directly into the housing. The mounting protrusions, recesses, and protective features are combined with the housing itself rather than being separate components, reducing overall device complexity while maintaining protection.
Solution Approach 2:
The resin mold portion serves multiple functions simultaneously: it provides structural support for the thermistor, offers protective embedding, enables electrical insulation, and facilitates mounting within the housing. This multi-functionality reduces the need for separate protective components, simplifying the overall device structure.
3Manufacturing precision
If the connecting portion is cut after molding, then the lead frames are separated properly, but the molding process requires precise timing
Solution Approach 1:
The patent performs the cutting operation after the molding process is complete, using the molded state as a preliminary stage before final separation. The resin is first molded with the lead frames connected, providing a stable structure, and then cutting is performed to achieve precise separation. This sequencing improves precision without significantly impacting overall productivity.
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 effectively protects the thermistor from damage and ensures reliable electrical connections, enhancing the accuracy and durability of temperature detection in oil temperature sensors.
Implementation Method 1
a resin mold portion in which the thermistor is buried
Implementation Method 2
a first lead frame including a first buried portion on which one end of the thermistor is mounted and which is buried in the resin mold portion
Data Source
AI summary
A method of manufacturing a sensor body used in an oil temperature sensor includes mounting a thermistor on a scheduled first resin mold portion and a scheduled second resin mold portion. The manufacturing method includes molding the scheduled first resin mold portion, the scheduled second resin mold portion, and the thermistor to form a resin mold portion. The manufacturing method includes cutting connecting portions, after the resin mold portion is formed, and separating a scheduled first-terminal-portion forming portion and a scheduled second-terminal-portion forming portion.