Shielded Wire Harness Sealing at the Crimped Shield Ring
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Solution Overview
Problem
Existing wire harness designs, such as those described in JP 2023-106 844 A, fail to adequately prevent water ingress at the crimped and fixed portion by the shield ring.
Innovation Solution
A wire harness design incorporating a shield electric wire with a braided member, a shield terminal, a shield ring, a packing, and a shrink tube, where the packing seals the first portion of the wire closer to one end of the shield ring and the shrink tube seals the second portion, effectively preventing water ingress at the crimped and fixed portion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a shield ring is crimped and fixed to sandwich a folded portion of the braided member, then the electrical connection is secured, but water can ingress to the crimped and fixed portion
Solution Approach 1:
The sealing function is divided into two segments: a packing that seals the first portion of the shield electric wire (positioned closer to one end), and a shrink tube that seals the second portion (positioned closer to the other end). This segmentation ensures that both sides of the crimped and fixed portion are protected from water ingress, while maintaining electrical connection reliability through the shield ring structure.
Solution Approach 2:
The packing and shrink tube act as intermediary sealing elements between the external environment and the crimped and fixed portion. The packing with its inner peripheral lip portion creates a first sealing barrier, while the shrink tube creates a second sealing barrier, together forming a comprehensive protection system that prevents water from reaching the electrical connection point.
2Object-affected harmful factors
If additional sealing components (packing and shrink tube) are added, then water ingress is suppressed, but device complexity increases
Solution Approach 1:
The packing is made of flexible material that can elastically deform to create an effective seal around the shield electric wire. The shrink tube is a thin-walled hollow cylindrical structure that, when shrunk, forms a tight sealing layer over the second portion of the wire and the shield ring. These flexible sealing components provide effective water protection without adding significant structural complexity.
Solution Approach 2:
The packing is positioned within or alongside the shield terminal assembly, while the shrink tube encompasses the packing, shield ring, and wire portions in a nested arrangement. This nesting approach allows multiple sealing functions to be integrated in a compact configuration, minimizing the overall increase in device complexity while achieving comprehensive water protection.
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 design effectively suppresses water ingress at the crimped and fixed portion by the shield ring, reducing manufacturing labor and cost while maintaining a reliable electrical connection.
Implementation Method 1
a shrink tube that integrally covers an outer peripheral surface of a second portion of the shield electric wire, the second portion being positioned closer to the other end portion side in the axial direction than the shield ring, an outer peripheral surface of the shield ring, and the outer peripheral surface of the shield terminal, and that performs sealing with respect to the outer peripheral surface of the second portion
Data Source
AI summary
A wire harness includes a shield electric wire that has a braided member; a shield terminal that covers an outer peripheral surface of the shield electric wire and is grounded to a shield shell; a shield ring that is crimped and fixed to sandwich a folded portion of the braided member between the shield ring and the shield terminal; a packing performing sealing with respect to an outer peripheral surface of the first portion of the shield electric wire; and a shrink tube. The shrink tube integrally covers an outer peripheral surface of a second portion of the shield electric wire, an outer peripheral surface of the shield ring, and the outer peripheral surface of the shield terminal, and that performs sealing with respect to the outer peripheral surface of the second portion.