Wire Harness Water Blocking Structure Low-Pressure Molding
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Solution Overview
Problem
Existing water blocking structures for wire harnesses face challenges such as low working efficiency due to slow solidification of single-component silicone-based systems, difficulty in managing butyl rubber, and inefficiencies in resin-based mold structures, which include issues like resin leakage and wire scratching during molding.
Innovation Solution
A water blocking structure using a hard resin stopper injection-molded at low pressure to surround wires, conforming to the inner shape of a wire passage portion, and a manufacturing method involving a low-pressure injection molding machine with flat burr-cutting portions to prevent resin leakage and wire damage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If single-component silicone is used as water-stop agent, then waterproof performance is improved, but solidification time increases and working efficiency decreases
Solution Approach 1:
The patent changes the material parameter from single-component silicone to two-component silicone, which fundamentally alters the curing mechanism. The two-component system uses crosslinking reaction between base resin and curing agent, enabling faster setting time while maintaining waterproof performance. This parameter change directly resolves the contradiction between waterproof reliability and solidification time.
2Reliability
If butyl rubber is used for water blocking, then waterproof performance is improved, but material management becomes difficult
Solution Approach 1:
The patent changes the material type from butyl rubber to two-component silicone, which fundamentally improves manageability. The silicone system provides clear visual indicators for charging state and maintains stable properties during processing, making material management significantly easier while preserving waterproof performance.
3Productivity
If injection molding is used for mold structure, then productivity is improved, but facility size and complexity increase
Solution Approach 1:
The patent adopts a simpler molding approach that does not require expensive, large-scale injection molding equipment. By using alternative molding methods with smaller, more accessible equipment, the facility size and complexity are reduced while maintaining manufacturing efficiency for the water blocking structure.
4Productivity
If ordinary injection molding machine is used, then productivity is improved, but resin leakage and wire scratching occur
Solution Approach 1:
The patent changes the molding parameters by using low-pressure injection instead of ordinary high-pressure injection molding. This parameter change prevents resin leakage and avoids wire scratching while maintaining manufacturing efficiency. The low-pressure process allows controlled resin flow that fills the mold cavity without causing harmful effects.
5Reliability
If burr-cutting portions with sharp projections are used, then resin leakage is prevented, but wire coatings are scratched
Solution Approach 1:
The patent changes the burr-cutting portion design from sharp projections to flat surfaces. This parameter change in the geometric shape eliminates wire scratching while maintaining the sealing function. The flat surface design prevents concentration of stress on wire coatings, avoiding damage while still preventing resin leakage through proper contact.
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 solution enhances waterproof performance, increases working efficiency by preventing resin leakage and wire scratching, and allows for easier handling and management of the water blocking material, while reducing facility size and operational complexity.
Implementation Method 1
an integrally molded stopper made of a hard resin that is injection-molded at a low pressure
Implementation Method 2
injecting the hard resin in a molten state into the cavities of the upper die and the lower die at a low pressure
Implementation Method 3
flat burr-cutting portions for holding an outer circumference of the set of wires between the upper die and the lower die
Data Source
AI summary
A water blocking structure of a wire harness and a method for manufacturing the wire harness is provided. The water blocking structure includes a set of wires including a plurality of wires arranged in at least one row and side by side in a direction of a diameter of the wire, and an integrally molded stopper made of a hard resin that is injection-molded at a low-pressure so as to surround a portion of the set of wires in an extending direction of the wires and to have an outer circumferential shape defining portion that conforms to an inner circumferential shape of a wire passage portion into which the set of wires is to be inserted.