Shape-Memory Protection Tube for Large-Connector Wire Harnesses
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Solution Overview
Problem
The existing methods for manufacturing wire harnesses require cumbersome operations such as widening slits in protection tubes and tape winding, which increase weight and risk damage to electric wires, especially when dealing with connectors of larger dimensions.
Innovation Solution
A method involving shape-memory polymer protection tubes that are shaped into a corrugated tube form, expanded to accommodate connectors of larger dimensions, and then cooled and reheated to fit snugly around electric wires without slits or seams, eliminating the need for cumbersome operations and tape winding.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a protection tube with a slit is used to accommodate connectors larger than the tube's inner dimension, then the connector can be mounted on the electric wire, but the slit requires cumbersome operations to widen and tape winding to secure the protection tube
Solution Approach 1:
The patent applies temperature parameter changes to the shape-memory polymer protection tube. By heating the tube to its transition temperature, the material softens and allows expansion to accommodate large-dimension connectors. After mounting, cooling the tube restores it to its original shape, creating a secure fit without slits or tape winding.
Solution Approach 2:
The protection tube utilizes phase transition of shape-memory polymer material. The tube transitions from a rigid state at room temperature to a soft, expandable state when heated to the transition temperature, enabling it to be mounted over large connectors. Upon cooling, it returns to its original rigid state, securing the connector in place.
2Ease of manufacture
If an overlapped wound portion is used in the protection tube to eliminate tape winding, then tape winding operations are eliminated, but the protection tube weight increases
Solution Approach 1:
Instead of adding structural material like overlapped wound portions, the patent uses parameter changes (temperature-induced shape memory effect) to achieve the same functional result. The protection tube maintains its original lightweight structure while gaining the ability to secure connectors through thermal expansion and contraction.
Solution Approach 2:
The patent replicates the securing function of tape winding and overlapped structures through a different mechanism - the shape-memory effect. The protection tube 'copies' the functional outcome (secure mounting) without replicating the heavy structural means (overlapped portions), thereby eliminating unnecessary weight.
3Adaptability or versatility
If the protection tube is made with a slit to accommodate large-dimension connectors, then mounting is possible, but the slit creates potential damage to electric wire covers and requires additional securing operations
Solution Approach 1:
The patent eliminates the slit by using parameter changes. The protection tube is heated to expand its inner dimension temporarily for mounting, then cooled to restore its original shape, creating a secure, slit-free fit that protects the electric wire cover while accommodating large connectors.
Solution Approach 2:
The patent performs preliminary heating and expansion of the protection tube before mounting, allowing the large-dimension connector to be inserted easily. After mounting, the tube is cooled to contract and secure the connector, eliminating the need for slits and subsequent securing operations that could damage the wire cover.
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 approach simplifies the mounting process, reduces weight, and prevents damage to electric wires by eliminating slits and seams, resulting in improved quality and ease of manufacturing for wire harnesses.
Implementation Method 1
heating it to a temperature equal to or higher than a glass-transition point
Implementation Method 2
cooling the electric wire protection tube to a temperature below the glass-transition point and solidifying the electric wire protection tube
Implementation Method 3
reheating the electric wire protection tube to a temperature equal to or higher than the glass-transition point such that the electric wire protection tube is restored to the inner dimension obtained after the step of shaping
Data Source
AI summary
A method of manufacturing a wire harness having an electric wire and a protection tube covering, one end side of the electric wire being provided with a large-dimension portion greater than an inner dimension of the protection tube, including shaping the electric wire protection tube made of shape-memory polymer into a tube shape; expanding the protection tube by heating to a temperature equal to or higher than a glass-transition point such that the inner dimension of the protection tube becomes larger than the large-dimension portion; cooling the protection tube to a temperature below the glass-transition point and solidifying the protection tube; passing the large-dimension portion and the electric wire inside the protection tube; and reheating the electric wire protection tube to a temperature equal to or higher than the glass-transition point such that the electric wire protection tube is restored to the inner dimension obtained after the step of shaping.