Bent Electric Wire Guide Body for Water Drainage in Vehicle Grommets

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Solution Overview

Problem

Water infiltration into the grommet body occurs through the electric wire insertion opening, compromising the protection of the wire harness in vehicles.

Innovation Solution

A grommet design featuring an elastic grommet body with a protector accommodating chamber, an inner protector of higher rigidity, and an outer member, where the electric wire guide body is bent to create a water draining portion between the support and tip portions, preventing water infiltration into the grommet body.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the electric wire guide body is made straight, then the wire harness routing is simple, but water can infiltrate into the protector accommodating chamber along the electric wire

Engineering Contradiction:

Improvewater infiltration preventionVSAvoidelectric wire guide body shape

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The electric wire guide body is designed with a bent shape instead of a straight configuration. Specifically, the guide body includes a first portion extending from the protector body and a second portion extending from the first portion in a direction substantially perpendicular to the longitudinal direction of the first portion, creating a curved path that prevents water infiltration while maintaining routing functionality.

Inventive Principle:

Principle #14Spheroidality (Curvature)

2Strength

If the grommet body is made of rigid material, then the structural strength is improved, but the sealing performance against water infiltration deteriorates

Engineering Contradiction:

Improvegrommet body strengthVSAvoidwater sealing performance

Core Design Contradiction:

StrengthVSReliability

Solution Approach 1:

The grommet system employs different material properties in different components: the grommet body is made of elastic material to provide sealing performance and conform to the recessed portion, while the inner protector and outer member are made of rigid materials to provide structural strength and protection. This local differentiation of material properties allows both sealing and strength requirements to be satisfied simultaneously.

Inventive Principle:

Principle #3Local quality

3Ease of operation

If the electric wire guide body projects straight out, then the wire harness installation is easier, but water can flow directly into the protector accommodating chamber

Engineering Contradiction:

Improvewire harness installationVSAvoidwater drainage capability

Core Design Contradiction:

Ease of operationVSReliability

Solution Approach 1:

The electric wire guide body is configured with a bent geometry including a first portion and a second portion extending perpendicular to the first portion. This curved configuration creates a water draining portion that prevents water from flowing directly into the protector accommodating chamber while still allowing wire harness installation through the bent path.

Inventive Principle:

Principle #14Spheroidality (Curvature)

Data Source

PatentUS11108218B2Grommet

Publication Date: 2021.08.31 YAZAKI CORP

AI summary

A grommet includes a grommet body, an inner protector, and an outer member. The inner protector includes a protector body accommodated in a protector accommodating chamber of the grommet body and an electric wire guide body projecting toward an outside of the protector accommodating chamber from the protector body. The electric wire guide body is bent such that an intermediate position between a support portion on a side of the protector body and a tip portion is lower than heights of both the support portion and the tip portion with the grommet installed in a vehicle body.