Bowden Cable Pulley Two-Layer PTFE Coating
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Solution Overview
Problem
Existing Bowden cables and cable pull elements face challenges in achieving improved lubricity, mechanical stability, and corrosion resistance, especially in chemically aggressive environments, which are only partially met by current technologies.
Innovation Solution
A two-layer PTFE coating system is applied to the wire rope, where the inner layer consists of modified polytetrafluoroethylene (PTFE) blended with a thermoplastic polymer, such as polyphenylene sulfide (PPS), providing a non-positive and positive connection, and the outer layer is formed through paste extrusion with a highly heat-resistant polymer, ensuring a mechanically strong and wear-resistant coating with low friction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If a single-layer PTFE coating is applied to the wire rope, then low friction and corrosion resistance are achieved, but mechanical stability and wire fixation are insufficient
Solution Approach 1:
The PTFE coating is divided into two distinct layers: an inner layer with modified PTFE for mechanical stability and wire fixation, and an outer layer with standard PTFE for low friction properties. This segmentation allows each layer to optimize its specific function without compromising the other.
Solution Approach 2:
The inner coating layer uses a composite material consisting of modified PTFE combined with other polymers or fillers to enhance mechanical properties while maintaining the base PTFE's corrosion resistance. This composite approach provides both structural integrity and protective properties.
2Length of moving object
If the PTFE coating is made thinner to reduce cable diameter, then cable flexibility improves, but wear resistance and protection quality decrease
Solution Approach 1:
The coating is segmented into two layers with different thicknesses and functions. The inner layer provides mechanical stability and wire fixation, while the outer layer delivers low friction and wear resistance. This segmentation allows optimal protection without excessive thickness.
Solution Approach 2:
Different regions of the coating have different properties: the inner layer is optimized for mechanical stability and adhesion to the wire rope, while the outer layer is optimized for low friction and wear resistance. Each layer's composition and thickness are tailored to its specific functional requirements.
3Reliability
If a highly cross-linked PTFE structure is used to improve wear resistance, then durability increases, but processing difficulty and manufacturing complexity increase
Solution Approach 1:
The manufacturing process is segmented into two separate coating applications. The inner layer can be applied with modified PTFE that may require cross-linking for mechanical stability, while the outer layer uses standard PTFE that is easier to process. This segmentation simplifies the overall manufacturing by dividing complex requirements into manageable steps.
Solution Approach 2:
The inner layer is applied and processed first to establish mechanical stability and wire fixation. This preliminary action creates a stable base that simplifies the subsequent application of the outer layer, reducing overall processing difficulty.
4Device complexity
If the cable pull element is designed with a single coating layer, then device complexity is reduced, but the ability to meet multiple performance requirements (lubricity, mechanical stability, corrosion resistance) is compromised
Solution Approach 1:
The coating system is segmented into two layers, each optimized for specific performance requirements. The inner layer addresses mechanical stability and corrosion resistance, while the outer layer provides low friction and lubricity. This segmentation enables the cable to meet multiple performance requirements simultaneously.
Solution Approach 2:
The dual-layer coating creates a composite structure where each layer contributes different properties. This composite approach allows the cable pull element to achieve a balance of lubricity, mechanical stability, and corrosion resistance that cannot be obtained with a single homogeneous coating.
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 a permanently wear-resistant and low-friction coating that securely fixes the steel wires, prevents corrosion, and maintains performance across a wide temperature range, ensuring reliable operation in chemically aggressive environments.
Implementation Method 1
the invention results in a permanent positive and non-positive connection between the surface of the wire rope and the outer coating
Implementation Method 2
it is particularly important to guide the force-transmitting cable element, usually a steel wire cable, in a surrounding support tube with as little friction as possible
Implementation Method 3
A second cylindrical shaped body with a central bore is again produced by paste extrusion
Data Source
AI summary
The pulley element or a part of Bowden cable for the transmission of pressure and pulling power during the operation of functional parts, about actuation of heating, ventilating or climate- controlling in automobiles or for operation of breaks in bicycle or for the transmission of powers on flaps or levers in machines, comprises a cable, which exists out of single stranded or choked steel wire (2). The cable has an external coating (3, 4) having two single layers by which the first layer is directly present on the cable through a thermoplastic high heat resistant polymer. The pulley element or a part of Bowden cable for the transmission of pressure and pulling power during the operation of functional parts, about actuation of heating, ventilating or climate- controlling in automobiles or for operation of breaks in bicycle or for the transmission of powers on flaps or levers in machines, comprises a cable, which exists out of single stranded or choked steel wire (2). The cable has an external coating (3, 4) having two single layers by which the first layer is directly present on the cable through a thermoplastic high heat resistant polymer. The wall thickness of the first layer amounts to 30-60% of the wall thickness of the total coating of the cable. An independent claim is included for method for the production of pulley element.