Shielded Twisted-Pair Cable for Bending-Resistant Noise Shielding
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Solution Overview
Problem
Communication cables used in vehicles face challenges with bending resistance and noise shielding, as existing two-core parallel cables have low bending resistance and flexibility, leading to potential damage and disruption of characteristic impedance when subjected to repeated bending.
Innovation Solution
A shielded communication cable design featuring twisted insulated wires with a braided shield and a film-shaped metal shield, where the wires are twisted with a pitch of 30 times the outer diameter or smaller, and a jacket with an inner diameter of 3.5 mm or smaller, maintaining a characteristic impedance of 100±5Ω and enhancing bending resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a two-core parallel cable with two-layer shield is used to improve noise shielding performance, then the shielding performance is improved, but the bending resistance deteriorates due to low flexibility and excessive load on the shielding layer
Solution Approach 1:
The cable structure is segmented into twisted pairs instead of parallel cores, dividing the signal transmission function into multiple twisted units that can independently accommodate bending stresses while maintaining overall shielding effectiveness
Solution Approach 2:
The cable employs a dynamic twisted pair configuration where the wires are twisted along their length with a controlled pitch, allowing the structure to flex and adapt to bending forces while maintaining electrical characteristics and shielding performance
2Device complexity
If a two-core parallel cable is used to achieve simple structure, then the structural complexity is reduced, but the flexibility and bending resistance deteriorate
Solution Approach 1:
The static parallel arrangement is replaced with a dynamic twisted configuration where the wire pairs are twisted along their length, providing flexibility and bendability while maintaining a relatively simple overall cable structure that can be manufactured using standard processes
3Adaptability or versatility
If repeated bending is applied to a two-core parallel cable, then the cable is subjected to movement conditions, but the characteristic impedance cannot be maintained due to changing distance between wires
Solution Approach 1:
The twisted pair configuration creates a dynamic structure where the wires maintain a relatively constant distance through their twisting geometry, allowing the cable to adapt to bending and movement while preserving the characteristic impedance required for proper signal transmission
Solution Approach 2:
The cable design controls the twist pitch parameter to be within a specific range (0.5 to 2 times the outer diameter of the insulated wire), which optimizes the balance between flexibility for movement and maintenance of electrical characteristics including characteristic impedance
Data Source
AI summary
A shielded communication cable. The shielded communication cable includes a pair of insulated wires twisted with each other containing a conductor and an insulation covering which covers the conductor and has the relative dielectric constant of 2.5 or lower, a braided shield which covers the pair of insulated wires, a film-shaped shield which contains a metal film and longitudinally laps the pair of the insulated wires over the braided shield and a jacket having an inner diameter of 3.5 mm or smaller which covers the film-shaped shield. The pair of insulated wires are twisted with each other with a twist pitch of 30 times of an outer diameter of each of the insulated wires or smaller, and the shielded communication cable has a characteristic impedance in range of 100±5Ω.