Grommet Fold-back Mechanism for Wire Harness Water Sealing
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Solution Overview
Problem
Conventional grommets face challenges in improving water stopping performance while maintaining workability during assembly, as extending the covering part to enhance water resistance complicates the passage of wire harnesses or washer hoses through the grommet.
Innovation Solution
A grommet design featuring a tubular part with a fold-back mechanism, where the fold-back part is foldable between an attachment position and a use position, allowing it to extend radially outside the tubular part main body, providing enhanced water stopping performance without compromising assembly workability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the part that covers the leading member is extended long to improve water stopping performance, then water stopping performance is improved, but it becomes difficult to pass the leading member through the grommet and workability deteriorates
Solution Approach 1:
The fold-back part is designed to be flexible and changeable in configuration. During assembly, it is folded back to reduce the effective length and facilitate passage of the leading member. After assembly, it is extended to provide sufficient water stopping coverage. This dynamic adjustment resolves the contradiction between needing long coverage for water stopping and short length for ease of assembly.
Solution Approach 2:
The fold-back part utilizes radial dimension by folding back toward the central axis of the grommet during assembly, effectively reducing the radial profile and length in the assembly direction. After assembly, it extends radially outward to provide the necessary water stopping barrier. This dimensional transformation allows the same structure to satisfy both assembly ease and water stopping requirements.
2Strength
If the fold-back part is folded back toward the holding part to press the holding part against the leading member, then holding force is improved, but the length available for water stopping coverage is reduced
Solution Approach 1:
The fold-back part transitions between two states: during assembly it is folded back to exert pressing force on the holding part for secure attachment, and after assembly it is extended to maximize water stopping coverage. This dynamic state change allows the structure to fulfill both holding and water stopping functions with the same component.
Solution Approach 2:
The grommet is divided into distinct functional segments: the holding part that provides attachment force and the fold-back part that provides water stopping coverage. The fold-back part acts as a separate segment that can independently change configuration - folded for holding, extended for water stopping - without compromising the other function.
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 fold-back mechanism allows for improved water stopping performance while maintaining ease of assembly by ensuring the grommet can be easily attached and covers the wiring material effectively, suppressing the deterioration in workability.
Implementation Method 1
the fold-back part is foldable between an attachment position where the fold-back part is folded back to outside of the tubular part main body, and a use position where the fold-back part is positioned on the side opposite to the side where the main body part is positioned
Data Source
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AI summary
A grommet (1) includes a main body part (10) fitted to a penetration hole (101) penetrating an attachment panel (100), and a tubular part (20) unified with the main body part (10) so as to have a tubular shape. The tubular part (20) includes a tubular part main body (50) formed continuing from the main body part (10), and a fold-back part (60) formed continuing from the tubular part main body (50) on a side opposite to a side where the main body part (10) is positioned in the axial direction (X) and that can be folded back to the outside of the tubular part main body (50). The fold-back part (60) is foldable between an attachment position where the fold-back part (60) is folded back to the outside of the tubular part main body (50), and a use position where the fold-back part (60) is positioned on the side opposite to the side where the main body part (10) is positioned.