Multi-Layer PPS Flat Cable for Rotary Connectors
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Solution Overview
Problem
Conventional flat cables used in rotary connectors face challenges with high production costs, heat resistance, and durability due to the use of polyester-based resins, which degrade at high temperatures, and PPS-based resins are expensive and difficult to produce using extrusion molding.
Innovation Solution
A flat cable design featuring multiple layers of polyphenylene sulfide-based resins with a lower melting point innermost layer and a higher melting point outermost layer, produced through thermal compression bonding, allowing for efficient and cost-effective production with excellent heat resistance and flexibility.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If polyester-based resins are used for the insulating coating, then the flat cable has good flexibility and low cost, but the resin undergoes degeneration at high temperature and exhibits heat setting phenomenon
Solution Approach 1:
The insulating coating is divided into multiple layers with different materials: the innermost layer uses polyester-based resin for flexibility and ease of manufacture, while outer layers use heat-resistant materials like polyimide or cycloolefin-based resin to prevent heat setting phenomenon. This segmentation allows each layer to perform its specific function optimally.
Solution Approach 2:
The patent employs composite material structure where polyester-based resin is combined with heat-resistant polymers in a multi-layer configuration. The composite structure integrates the advantages of both materials: the flexibility and low cost of polyester with the high-temperature stability of polyimide or cycloolefin-based resin, preventing degeneration at high temperatures.
2Reliability
If PPS-based resin is used for the insulating film, then the flat cable has high heat resistance and flame retardance, but the production cost becomes very high and production is difficult
Solution Approach 1:
Instead of using PPS-based resin throughout the entire insulating coating, the patent segments the coating into multiple layers where only the outermost layer uses heat-resistant material like polyimide or cycloolefin-based resin, while inner layers use more easily manufactured materials. This reduces production complexity and cost while maintaining heat resistance where it is most needed.
Solution Approach 2:
The patent applies heat-resistant materials locally at the outermost layer where heat resistance is most critical for preventing heat setting phenomenon, while using more cost-effective and easier-to-manufacture materials in inner layers. This local quality approach optimizes the balance between heat resistance and ease of manufacture.
3Temperature
If the flat cable is placed in a high-temperature environment, then heat dissipation becomes more difficult, but the polyester-based insulating coating undergoes heat setting phenomenon and curls
Solution Approach 1:
The insulating coating is segmented into multiple layers with the outermost layer using heat-resistant material to maintain shape stability at high temperatures, while inner layers provide flexibility. This prevents the heat setting phenomenon that causes curling in single-layer polyester coatings.
Solution Approach 2:
The composite multi-layer structure combines polyester-based resin with heat-resistant polymers, where the heat-resistant outer layer acts as a constraint that prevents the inner polyester layer from undergoing heat setting phenomenon and curling, even in high-temperature environments with difficult heat dissipation.
4Temperature
If cycloolefin-based resin is used for the insulating film, then the melting point is high, but the resin swells due to lubricating agent and film thickness becomes non-uniform
Solution Approach 1:
The patent uses cycloolefin-based resin only in the outermost layer where high melting point is needed, while inner layers use materials less sensitive to lubricating agent swelling. This segmentation reduces the overall impact of swelling on film thickness uniformity while maintaining the high-temperature performance where it is most critical.
Solution Approach 2:
The cycloolefin-based resin with high melting point is applied locally at the outermost layer where thermal stability is most important, while inner layers use materials that are more dimensionally stable in the presence of lubricating agents, thus maintaining overall film thickness uniformity.
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 an inexpensive, durable, and flexible flat cable with enhanced heat resistance and flame retardance, suitable for high-temperature environments, while reducing production costs and complexity.
Implementation Method 1
the melting point of the polyphenylene sulfide-based resin that constitutes the innermost layer is lower by 5° C. or more than the melting point of the polyphenylene sulfide-based resin that constitutes the outermost layer
Data Source
AI summary
A flat cable 10 according to the invention has a plurality of arrayed conductors 11; and an insulating layer 12 covering the periphery of the conductors 11 with a coating film, in which the insulating layer 12 includes a plurality of layers, the outermost layer 13 of the insulating layer 12 and the innermost layer 14 contacting the conductors are both formed from polyphenylene sulfide-based resins, and the melting point of the polyphenylene sulfide-based resin constituting the innermost layer 14 is lower by 5° C. or more than the melting point of the polyphenylene sulfide-based resin constituting the outermost layer 13.