Thermal Protector With Integrated Resistor Plate
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional thermal protectors require an additional manufacturing step and increased costs due to the incorporation of a separate resistor component for producing Joule heat, which complicates the design and increases pricing.
Innovation Solution
A thermal protector design that utilizes a bimetal with a warpage direction inverted at a predetermined temperature, where a slim hole partitions the movable plate into a wide-width and narrow-width part, allowing the narrow-width part to function as both a conductor and resistor, eliminating the need for a separate resistor component and simplifying the manufacturing process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a separate resistor component is incorporated to produce Joule heat, then thermal responsiveness and current responsiveness are improved, but device complexity and manufacturing cost increase
Solution Approach 1:
The patent merges the resistor function with the movable plate structure by creating a narrow-width part that serves as an integrated resistor. This eliminates the need for a separate resistor component while maintaining the thermal responsiveness required for overcurrent protection. The narrow-width part is formed by cutting a slim hole through the movable plate, creating a high-resistance path that generates Joule heat directly within the existing structure.
Solution Approach 2:
The movable plate is designed to serve multiple functions: it acts as both the movable contact carrier and the resistor element. The narrow-width part of the movable plate functions as a heater that generates Joule heat during overcurrent conditions, while the wide-width part maintains the spring property for normal operation. This multi-functionality reduces component count and simplifies the overall device structure.
2Reliability
If a separate resistor component is incorporated to produce Joule heat, then current responsiveness is improved, but manufacturing cost increases
Solution Approach 1:
The resistor function is merged into the movable plate by forming a narrow-width part through cutting a slim hole. This integration eliminates the need for separate resistor components and their associated assembly steps, thereby reducing manufacturing cost while maintaining current responsiveness. The high-resistance path is created directly within the movable plate structure during the same manufacturing process.
Solution Approach 2:
The resistor function is extracted from a separate component and integrated into the movable plate itself. By removing the need for an external resistor and incorporating the heating function directly into the movable plate's narrow-width part, the patent simplifies the manufacturing process and reduces component procurement costs while maintaining the required current responsiveness.
3Reliability
If the movable plate is made thinner to reduce resistance, then contact responsiveness is improved, but structural strength decreases
Solution Approach 1:
The movable plate is designed with non-uniform thickness through the narrow-width and wide-width parts. The narrow-width part has reduced thickness to provide low resistance for rapid contact responsiveness, while the wide-width part maintains sufficient thickness to provide the necessary spring property and structural strength. This local variation in quality allows the plate to simultaneously achieve both responsiveness and strength requirements.
Solution Approach 2:
The movable plate is segmented into functional zones: the narrow-width part serves as the low-resistance contact path for responsiveness, while the wide-width part provides the spring property and structural support. This segmentation allows each region to be optimized for its specific function without compromising the overall performance of the movable plate.
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
This design achieves superior current and thermal responsiveness with a simple configuration, reducing processing costs and maintaining the spring property of the wide-width part, while the narrow-width part operates effectively as a resistor, enhancing the thermal protector's reliability and responsiveness.
Implementation Method 1
a bimetal having a warpage direction that is inverted at a predetermined temperature in response to a change of an ambient temperature
Implementation Method 2
the narrow-width part... operates effectively as a resistor
Data Source
AI summary
A thermal protector has superiority in current responsiveness or thermal responsiveness with a simple configuration that does not need a separate manufacturing step of incorporating a resistor. At a stage of press processing for cutting from an original material, a movable plate body part of a movable plate is partitioned into a narrow-width part and a wide-width part by a slim hole. The movable plate is assembled to a fixed conductor with columns of an insulator, a bimetal is assembled to the movable plate, the entire configuration is pressed down by a resinous block, and the entire fixing part is fixed by melting tips of the columns. The wide-width part serves as a normal movable plate, whereas the narrow-width part serves as a conductor in a normal state and as a resistor against an overcurrent.