Segmented Grommet Assembly for Secure Sealing and Holding Force
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Solution Overview
Problem
Conventional grommets face issues with maintaining a holding force between the base member and grommet main body due to excessive mold loads, leading to potential deformation and gaps, especially when the base member and grommet main body are integrally molded.
Innovation Solution
A grommet design featuring a cylindrical base member with an annular flange and cylindrical body, combined with an annular grommet main body made of elastically deformable and harder materials, and engagement mechanisms to secure the assembly, including hollow and projection shapes for engagement, ensuring a stable fit.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the base member and grommet main body are integrally molded, then the manufacturing process is simplified and production efficiency is improved, but excessive mold load causes deformation and gaps reducing assembly precision
Solution Approach 1:
The grommet is divided into two separate parts: a base member and a grommet main body. This segmentation allows each part to be molded independently with appropriate mold loads, avoiding deformation while maintaining manufacturing efficiency. The separate parts are then assembled through engagement mechanisms to form the complete grommet assembly.
2Reliability
If the base member size is increased to accommodate wiring member passage, then the wiring protection function is improved, but the base member shape becomes complicated increasing mold complexity
Solution Approach 1:
The base member is segmented into a flange portion and a cylindrical body portion. The flange provides a simple mounting surface for waterproofing, while the cylindrical body provides the through-hole for wiring passage. This segmentation simplifies the mold design while maintaining the protective function.
3Strength
If engagement mechanisms are added between base member and support member, then the holding force is improved, but the device complexity increases
Solution Approach 1:
Engagement mechanisms are placed at specific locations (four positions) around the circumference of the base member and support member. This localized approach provides sufficient holding force through strategic positioning while keeping the overall design simple and avoiding excessive complexity.
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 design maintains a strong holding force and prevents liquid ingress by ensuring a secure assembly and minimizing mold-induced deformation, thus enhancing the grommet's durability and sealing effectiveness.
Implementation Method 1
a plurality of engagement mechanisms for engaging a first engagement portion provided in the base member with a second engagement portion provided in the support member and holding the base member and the grommet main body at the assembly completion position are provided around an axis of a cylinder axis of the base member
Implementation Method 2
an annular grommet main body which is coaxially assembled to the base member and is disposed in the one space at an attachment completion position on the peripheral edge portion of the through-hole of the insertion object, wherein the grommet main body is a molded article formed by integrally molding an annular waterproof member made of an elastically deformable synthetic resin material
Data Source
AI summary
A base member made of a hard resin, and a grommet main body formed by integrally molding a waterproof member made of an elastically deformable soft resin and a support member made of a hard resin and assembled to the base member, are provided, and a plurality of engagement mechanisms for engaging a first engagement portion of the base member with a second engagement portion of the support member and holding the base member and the grommet main body at the assembly completion position are provided around an axis of a cylinder axis of the base member, between the base member and the support member.