Angled Bimetal Thermal Protector for Simpler Terminal Forming
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Solution Overview
Problem
The complexity of processing parts in existing thermal protectors, such as those described in Patent Document 1, is high due to the two-step bending required in press-working of metal plates after resin molding, which complicates the manufacturing process.
Innovation Solution
A thermal protector design featuring terminals with slits and bimetal engagement, where the fixed and movable contacts are positioned at acute angles, reducing the need for two-step bending and simplifying the processing complexity, and allowing the bimetal to be disposed at an angle relative to the mounting surface for improved heat sensing and reduced heat exposure during normal operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If two-step bending is used in press-working of metal plates after resin molding, then the thermal protector can be manufactured with proper structural integrity, but the processing complexity increases significantly
Solution Approach 1:
The metal plate is divided into distinct functional regions: a first metal plate portion forming the first terminal, a second metal plate portion forming the second terminal, and a third metal plate portion forming the bridge portion. This segmentation allows each region to be formed with appropriate bending angles independently, reducing overall processing complexity while maintaining structural integrity.
Solution Approach 2:
The invention employs asymmetric bending angles for different portions of the metal plate. The first metal plate portion is bent at a first bending angle, the second metal plate portion at a second bending angle, and the bridge portion at a third bending angle that differs from the first and second angles. This asymmetric approach optimizes each region's structural requirements without requiring uniform complex processing throughout.
2Device complexity
If the bimetal is positioned parallel to the mounting surface, then the structure is simpler, but the heat sensing capability and ability to detect abnormalities quickly is reduced
Solution Approach 1:
The bimetal is positioned at an angle relative to the mounting surface, transitioning from a two-dimensional parallel arrangement to a three-dimensional angular configuration. This angular positioning allows the bimetal to extend toward the heat source more effectively, improving heat sensing capability and abnormality detection speed while maintaining reasonable structural complexity.
3Reliability
If the bimetal is positioned closer to the heat source for better heat sensing, then the abnormality detection improves, but the heat exposure during normal operation increases
Solution Approach 1:
The bridge portion is designed with specific bending characteristics that create a controlled thermal pathway. The third bending angle of the bridge portion positions the bimetal to sense heat abnormalities effectively while the insulating properties of the bridge structure limit excessive heat exposure during normal operation, creating different thermal conditions in different regions.
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 reduces processing complexity, enhances the thermal protector's ability to detect abnormalities quickly, and minimizes heat exposure during normal operation while ensuring effective shutdown of electrical products to prevent overheating.
Implementation Method 1
a bimetal engaged with the movable plate
Data Source
AI summary
A thermal protector includes: a first terminal and a second terminal that are provided at both ends in a longitudinal direction and connected to an external circuit; an insulation block that holds the first terminal and the second terminal; a fixed contact and a movable contact capable of coming into contact with each other; a movable plate having the movable contact provided at a leading end; and a bimetal engaged with the movable plate. Each of the first terminal and the second terminal has a main body, an extension, and a slit. The main body of the first terminal and the main body of the second terminal lie in a first plane, and a fixed contact support part of the extension and a movable plate support part of the extension lie in a second plane. An angle formed by the first plane and the second plane is an acute angle.