Composite Grommet Assembly for Bolt-Load Sealing
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing fluid systems in machines, particularly those used in engine aftertreatment systems, face challenges with grommets that can become impermeable when submerged, leading to air entrapment and fuel gassing issues.
Innovation Solution
A grommet assembly for an engine aftertreatment system is designed with a skirt portion made of a resilient material and a carrier portion made of a less compressible material, featuring bolt holes formed in the carrier to maintain structural integrity under bolting loads.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a grommet is made entirely of compressible material to ensure sealing, then sealing performance is improved, but structural integrity under bolting loads deteriorates
Solution Approach 1:
The grommet is constructed as a composite structure with a compressible material portion (skirt) for sealing and a less compressible material portion (flange) for structural support. This composite approach allows each material to perform its optimal function without compromising the other.
Solution Approach 2:
The grommet is divided into distinct functional segments: a skirt portion made of compressible material for sealing against the tank opening, and a flange portion made of less compressible material for maintaining structural integrity under bolting loads. Each segment is optimized for its specific function.
2Strength
If a grommet is made entirely of less compressible material to maintain structural integrity, then structural integrity under bolting loads is improved, but sealing performance deteriorates
Solution Approach 1:
The grommet combines materials with different compressibility characteristics - the flange uses less compressible material for structural support while the skirt uses compressible material for sealing, creating a composite structure that excels at both functions simultaneously.
Solution Approach 2:
Different regions of the grommet have different material properties tailored to local requirements: the flange region uses less compressible material where structural strength is needed, while the skirt region uses compressible material where sealing is critical.
3Device complexity
If a grommet is designed with integrated bolt holes to simplify assembly, then device complexity is reduced, but manufacturing precision requirements increase
Solution Approach 1:
The bolt holes are formed directly in the flange portion of the grommet itself rather than requiring separate alignment and fastening operations. This integration of the fastening features into the grommet structure simplifies the overall assembly process while the molding process maintains adequate manufacturing precision.
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 assembly effectively prevents air entrapment and fuel gassing by maintaining permeability and structural integrity, ensuring reliable operation of the fluid system.
Implementation Method 1
a skirt portion made at least in part of a first material, and a flange portion made at least in part of a second material, with the second material being less compressible than the first material
Data Source
AI summary
A grommet includes a skirt portion made at least in part of a skirt material. The grommet further includes a carrier attached to the skirt portion and made at least in part of a second material more resistant to deformation than the skirt material. The grommet further includes a plurality of bolt holes formed in the carrier, and formed at least in part by the second material. Forming the bolt holes at least in part of the second material imparts greater resistance to the carrier taking a set in the vicinity of the bolt holes and reducing a bolting load on the grommet over time.