Wire Harness Grommet Structure With Protected Rear-Side Hinge

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Solution Overview

Problem

Existing grommets with hinge portions exposed on the front surface of attachment panels are susceptible to damage from external forces, such as flying stones during automobile travel.

Innovation Solution

A grommet design with a hinge portion located on the back surface of the attachment panel, integrated clamping bodies, and a configuration that reduces part count and minimizes exposure to external forces, using a shaft and bearing mechanism for opening and closing, and elastic engagement with the attachment hole.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If the hinge portion is located on the front surface side of the attachment panel, then the grommet structure is simpler, but the hinge portion is susceptible to damage from external forces such as flying stones

Engineering Contradiction:

Improvedamage to hinge portionVSAvoidgrommet structure

Core Design Contradiction:

Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The hinge portion is repositioned from the front surface to the back surface of the attachment panel, utilizing the depth dimension to protect it from external forces like flying stones while maintaining the overall grommet structure

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

2Ease of operation

If the hinge portion is formed of resin material for elastic deformation, then the grommet can open and close easily, but the hinge portion may be damaged by repeated opening and closing

Engineering Contradiction:

Improveopening and closingVSAvoidhinge portion durability

Core Design Contradiction:

Ease of operationVSReliability

Solution Approach 1:

The hinge portion material is changed from resin to metal, altering the physical parameters to provide both the necessary elasticity for repeated opening/closing operations and the strength to prevent damage from fatigue

Inventive Principle:

Principle #35Parameter changes

3Strength

If the engagement portion engages deeply with the attachment hole, then the grommet is securely attached, but excessive insertion may occur causing damage

Engineering Contradiction:

Improveattachment strengthVSAvoidexcessive insertion damage

Core Design Contradiction:

StrengthVSObject-affected harmful factors

Solution Approach 1:

A protrusion is provided on the engagement portion that preliminarily contacts the attachment hole edge, establishing a stop position before full insertion occurs, thus preventing excessive insertion while maintaining secure attachment

Inventive Principle:

Principle #10Preliminary action

Data Source

PatentUS12589706B2Grommet and grommet attachment structure

Publication Date: 2026.03.31 NIFCO INC

AI summary

A grommet includes: a pair of clamping bodies that clamp a wire harness; a hinge portion that openably and closably couples the pair of clamping bodies; and an engagement portion that is provided at the pair of clamping bodies and that engages with an attachment hole formed in an attachment panel in a state in which the wire harness and the hinge portion clamped by the pair of clamping bodies are inserted into the attachment hole.