Vehicle Grommet Lip Mountain Deformation for Reduced Mounting Force
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Solution Overview
Problem
Existing grommets require excessive force for mounting due to their design, which involves pulling or pushing the cylinder toward the inner cabin side, leading to instability and potential incomplete fitting.
Innovation Solution
A grommet design featuring a lip mountain structure with a pressing surface portion that reduces the diameter of the lip mountains by sliding into the through hole, facilitated by a working portion and connection portion with an inclined and convex shape, allowing easy mounting by pushing toward the inner cabin side and enhancing waterproof sealing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the inner cabin side portion is pulled toward the inner cabin side during mounting, then the grommet can be fitted into the through hole, but an excessive force is required to push the outer cabin side portion toward the inner cabin side
Solution Approach 1:
The patent changes the geometric parameters of the inner cabin side lip by making the outer diameter small at the front end, gradually increasing toward the fitting portion, then decreasing again. This creates a mountain-shaped cross-section that controls the deformation sequence during mounting, allowing the grommet to slide in easily while reducing the pushing force required
Solution Approach 2:
The patent introduces dynamic deformation characteristics to the inner cabin side lip, allowing it to change shape during the mounting process. The lip deforms elastically as it is pushed into the through hole, with the outer diameter dynamically adjusting to facilitate entry and then expanding to create the waterproof seal
2Ease of operation
If the outer diameter of the inner cabin side lip is small at the front end and gradually increases toward the fitting portion, then the grommet can slide into the through hole, but an excessive force is required when the connection portion is connected
Solution Approach 1:
The patent segments the inner cabin side lip into distinct zones with different outer diameters: a small diameter front end for easy insertion, a gradually increasing section for controlled deformation, and a reduced diameter section near the fitting portion for connection. This segmentation allows different portions to perform different functions during the mounting process
Solution Approach 2:
The patent designs the lip geometry in advance so that the small front end diameter facilitates initial insertion into the through hole before the connection portion is engaged. The preliminary shaping of the lip creates favorable conditions for the subsequent connection operation, reducing the force needed during assembly
3Reliability
If the inner cabin side lip is increased in diameter by receiving an axial compressive force, then the connection portion can be connected, but an excessive force is required to mount the grommet
Solution Approach 1:
The patent employs curved, mountain-shaped geometry in the inner cabin side lip instead of straight or angular forms. The curved profile allows gradual deformation under compressive force, distributing the mounting load and enabling the lip to expand reliably to create the waterproof seal without requiring excessive force
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 grommet can be easily mounted with reduced force requirements and ensures a secure, waterproof fit by deforming the lip mountains to fit into the through hole, reducing the need for excessive force and enhancing stability and sealing.
Implementation Method 1
When the work pressing portion is pressed toward an inner cabin side, the pressing surface portion abuts on the lip mountain and the lip mountain is pushed toward the inner cabin side
Implementation Method 2
the lip mountains are reduced in diameter by sliding into the through hole while being deformed
Data Source
AI summary
A grommet mounted to a through hole formed in a vehicle body panel includes an inner cabin side harness insertion portion that projects toward an inner cabin side through which a wire harness penetrate, an outer cabin side harness insertion portion that projects toward an outer cabin side through which the wire harness penetrate, a lip mountain integrated with the inner cabin side harness insertion portion, a panel abutting portion that abuts on a periphery of the through hole on an outer cabin side of the vehicle body panel, a connection portion that connects the lip mountain and the panel abutting portion, a working portion formed across the outer cabin side harness insertion portion and the panel abutting portion, a work pressing portion integrated with the outer cabin side harness insertion portion and the working portion, and a pressing surface portion that is integrated with the work pressing portion and protrudes toward the lip mountain.