Wire Harness Pipe Diameter Reduction for Rattle Suppression
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Solution Overview
Problem
In hybrid vehicles, wire harnesses experience noise and damage due to wire rattling within metal pipes caused by vehicle vibrations, as existing designs fail to adequately secure the wires.
Innovation Solution
A wire harness exterior structure featuring a pipe with a diameter reduction portion that reduces the wire insertion space, combined with a tubular shielding member and an annular member that fixes the shielding member to the pipe, minimizing wire movement and noise generation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If wires are inserted through a metal pipe for protection and shielding, then wire protection and noise shielding are improved, but wire rattling occurs due to clearance between wires and pipe inner surface
Solution Approach 1:
The pipe structure is modified by adding a diameter reduction portion at specific locations where wires pass through. This creates a local narrowing that reduces clearance between the wires and pipe inner surface at critical points, suppressing rattling noise while maintaining overall wire protection and shielding functions.
Solution Approach 2:
Instead of modifying the wire or adding separate restraining components, the solution changes the pipe's cross-sectional dimension dynamically along its length. The diameter reduction portion creates a localized dimensional change in the pipe structure that actively engages with the wires to prevent movement and rattling.
2Object-generated harmful factors
If a diameter reduction portion is added to reduce wire insertion space and suppress rattling, then noise suppression is improved, but pipe structure complexity increases
Solution Approach 1:
The diameter reduction portion is integrated directly into the pipe structure as a continuous formation rather than being a separate component. This merging of the noise suppression feature into the main pipe body eliminates the need for additional parts, reducing overall structure complexity while maintaining the rattling suppression function.
Solution Approach 2:
The pipe structure itself provides the noise suppression function through its own geometric modification. The diameter reduction portion is formed as part of the pipe manufacturing process, allowing the pipe to serve both its protective/shielding function and its noise suppression function without requiring external components or complex assembly.
Data Source
AI summary
An exterior structure for a wire harness is provided with a pipe that has an electric wire insertion space that allows an electric wire to be inserted through the inside of the pipe. The pipe includes a diameter reduction portion that is defined by an inward deformation of the pipe in a diameter direction that narrows the electric wire insertion space. In the diameter reduction portion, the clearance between (i) the electric wire that is inserted through the electric wire insertion space of the pipe and (ii) the inner circumferential surface of the pipe can be reduced or eliminated, which suppresses rattling of the electric wire.