Rotary Swaged Litz Inner Conductor for Coaxial Cable
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Solution Overview
Problem
Conventional coaxial cables with litz inner conductors experience mechanical and electrical issues such as increased insertion loss and frequency-dependent return loss spikes due to the structural design and surface texture of the inner conductor, leading to suboptimal signal transmission properties.
Innovation Solution
A method involving the production of a litz inner conductor by stranding multiple wires with a constant or variable pitch, followed by rotary swaging to ensure tight wire abutment and a homogenous surface, encasing with a dielectric and outer conductor, and applying a protective sheath, utilizing coatings like silver, gold, or tin to enhance conductivity and mechanical stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a litz inner conductor with multiple stranded wires is used, then mechanical flexibility is improved, but return loss spikes and insertion loss increase due to surface texture and wire arrangement irregularities
Solution Approach 1:
The patent applies preliminary action by performing rotary swaging on the litz conductor before final cable assembly. This pre-compression process densifies the wire arrangement and creates a homogenous surface texture in advance, preventing the irregularities that would otherwise cause return loss spikes and insertion loss during signal transmission.
Solution Approach 2:
The patent changes physical parameters of the litz conductor through rotary swaging, which compresses the wires to increase density and alter surface texture. This parameter change from loose stranded structure to compressed homogenous structure eliminates the harmful effects while preserving mechanical flexibility.
2Strength
If wires are stranded with tight arrangement, then mechanical strength is improved, but frequency-dependent return loss spikes occur due to surface irregularities
Solution Approach 1:
The rotary swaging process is applied as a preliminary action to compress and densify the wire arrangement before cable assembly. This pre-compression creates a homogenous surface texture that eliminates the irregularities causing return loss spikes, while the tight wire arrangement maintained during swaging preserves mechanical strength.
Solution Approach 2:
The patent applies local quality by creating a specific compressed zone in the litz conductor through rotary swaging. The compression is applied locally to densify the wire arrangement and smooth the surface texture in the critical regions where signal transmission occurs, while maintaining the overall stranded structure for mechanical strength.
3Manufacturing precision
If rotary swaging is applied to compress the litz conductor, then wire abutment and surface homogeneity are improved, but manufacturing complexity increases
Solution Approach 1:
The rotary swaging device performs multiple functions simultaneously: it compresses the litz conductor, densifies the wire arrangement, creates homogenous surface texture, and maintains circular cross-section geometry. This multi-functionality achieves high manufacturing precision without requiring multiple separate processing steps, thereby limiting the increase in manufacturing complexity.
Solution Approach 2:
The rotary swaging process controls parameter changes systematically by adjusting compression force, rotation speed, and pass number to achieve the desired wire abutment and surface homogeneity. These controlled parameter changes produce consistent results while keeping the manufacturing process manageable through standardized parameters.
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 method improves mechanical flexibility, reduces return loss spikes, and maintains signal integrity by ensuring tight wire arrangement and constant cross-section, resulting in enhanced electrical and mechanical properties of the coaxial cable.
Implementation Method 1
the forming tool comprises a central, mostly continuous, working opening which has a tapering cross section in the longitudinal direction. Work pieces to be processed can be introduced into the working opening of the forming tool and removed via the same opening or, in the case of a continuous process, via a second opposite opening. The work piece is continuously deformed within the working opening by means of the jaws which move in the radial and circumferential direction.
Implementation Method 2
The jaws of the forming tool are for example deflected inwards in the radial direction by means of circumferential rollers. At the same time, said jaws move in the circumferential direction. The work piece is continuously deformed within the working opening by means of the jaws which move in the radial and circumferential direction.
Implementation Method 3
The surface of the wires is coated as required prior to stranding and/or prior to rotary swaging. Good results can be obtained using coatings made of silver, gold or tin.
Data Source
AI summary
The invention relates to a method for producing a stranded inner conductor (1), and to a coaxial cable (9). In a first step, a stranded inner conductor (2) is provided, which consists of several wires (3) twisted together. Then the stranded inner conductor (1) is rotary swaged by means of a rotary swaging device (10). In a further step, the rotary swaged stranded inner conductor (3) is enclosed with a dielectric (4). In a further step, the dielectric (4) is enclosed with an outer conductor (5) and a cable sheath (6).