Flexible Grommet Propeller Opening for Easier Cable Harness Insertion
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Solution Overview
Problem
The production process for bulkhead grommets in the automotive industry is complex, time-consuming, and requires significant operator effort, making it difficult to efficiently manage the increasing number of electrical cables and harnesses in electric vehicles.
Innovation Solution
A grommet design featuring a sleeve body with a propeller-shaped opening that unfolds to increase the cross-sectional area, allowing for easier insertion and guidance of larger cables or harnesses without stretching the material, thereby simplifying the production process and reducing operator workload.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a standard circular opening is used in the grommet, then the grommet material can be stretched to accommodate cables, but the production process becomes complex and time-consuming requiring significant operator effort
Solution Approach 1:
The grommet opening transitions from a static circular shape to a dynamic propeller shape that can unfold during cable insertion. The propeller blades are designed to flex and open up when force is applied, automatically adjusting the opening size to match the cable diameter without requiring manual stretching or complex positioning operations
Solution Approach 2:
The opening geometry changes from a small circular cross-section in the unloaded state to a large propeller-shaped cross-section when unfolded. This parameter change allows the same material to provide both a tight seal for small cables and a large opening for easy insertion of larger cables or harnesses, eliminating the need for operators to manually adjust the opening size
2Ease of operation
If the grommet opening is made larger to accommodate larger cables, then cable insertion becomes easier, but the material must be stretched more which increases the risk of damage
Solution Approach 1:
The propeller-shaped opening provides a dynamic structure that unfolds in a controlled manner during cable insertion. The blade design distributes the mechanical stress evenly across the material, preventing localized over-stretching and reducing the risk of material damage while still accommodating large cable diameters
Solution Approach 2:
The opening is segmented into multiple propeller blades that can flex and move independently during insertion. This segmentation allows the opening to adapt to different cable sizes by adjusting the degree of unfolding, providing ease of insertion for large cables while maintaining material integrity through distributed stress
3Reliability
If the grommet opening is made smaller to maintain material integrity, then material damage risk is reduced, but cable insertion becomes difficult and time-consuming
Solution Approach 1:
The propeller opening provides a dynamic solution where the same small-material-grommet maintains its compact form during storage and handling (preserving material integrity) but automatically unfolds to a large opening during cable insertion (reducing insertion time). The unfolding action is triggered by the insertion force itself, eliminating the need for separate opening operations
Solution Approach 2:
The propeller-shaped opening serves multiple functions: it provides a tight seal when closed (maintaining material integrity), unfolds to accommodate various cable sizes (reducing insertion time), and can be reset for repeated use. This multi-functionality eliminates the need for different grommet sizes for different cable applications
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 propeller-shaped grommet design allows for the efficient handling of cables and harnesses with diameters up to 50 mm or larger, reducing production time and operator effort while minimizing the risk of material damage, and enabling easier automation of the assembly process.
Implementation Method 1
The standard grommet material currently employed e.g., in the automotive industry can be stretched up to 400%. The design of a propeller shaped opening allows a significant increase in the clearance of the grommet without the need to stretch the material
Data Source
AI summary
This disclosure presents a grommet designed for accommodating cables, particularly in a vehicle wire harness application. The grommet features a sleeve body made of flexible material with two opposing openings. The first opening is uniquely shaped like a propeller in cross-section when viewed along the axial insertion direction in an unloaded state. This innovative design allows for efficient and secure cable insertion and retention within the grommet, enhancing the overall functionality and reliability of cable management systems in various vehicle applications.