Composite Drive Shaft End Fitting Bonding
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Solution Overview
Problem
Conventional composite drive shafts face challenges in achieving strong connections between composite core structures and metallic end fittings, leading to inadequate transfer of rotational power due to insufficient bonding strength, which results in increased complexity and weight.
Innovation Solution
A composite drive shaft assembly with a core structure formed by weaving fibers into an open composite structure, featuring helically shaped grooves and through holes on end pieces, where fibers are woven into these features and secured with structural adhesives, eliminating the need for mechanical fasteners.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If conventional adhesives or mechanical fasteners are used to bond composite core structure to metallic end fittings, then bonding strength is improved, but device complexity and weight increase
Solution Approach 1:
The patent merges the composite core structure and metallic end fitting into a single integrated component. The metallic end fitting is formed directly from the composite material through differential curing, eliminating the need for separate bonding operations and mechanical fasteners. This integration resolves the contradiction by achieving strong bonds without adding complexity from multiple components and fastening mechanisms.
Solution Approach 2:
The patent uses composite materials with different cure rates - a fast-curing material for the end fitting and a slow-curing material for the composite core. This allows the metallic end fitting and composite core to be formed as an integrated structure with inherent bonding strength, avoiding the need for additional adhesives or mechanical connectors, thus reducing complexity while maintaining strength.
2Strength
If conventional adhesives or mechanical fasteners are used to bond composite core structure to metallic end fittings, then bonding strength is improved, but weight increases
Solution Approach 1:
By merging the composite core and metallic end fitting into one integrated component formed through differential curing of composite materials, the patent eliminates the weight of separate adhesives and mechanical fasteners. The integrated structure achieves bonding strength through the material transition zone itself, reducing overall weight while maintaining connection strength.
Solution Approach 2:
The use of composite materials with different cure characteristics allows the creation of an integrated structure where the bonding interface is formed by the material transition rather than additional bonding agents. This eliminates the weight penalty associated with conventional adhesives and mechanical fastening systems while maintaining adequate bonding strength.
3Ease of manufacture
If conventional composite materials are used, then manufacturing is simplified, but bonding strength to metallic end fittings is insufficient
Solution Approach 1:
The patent changes the material parameters by using composite materials with different cure rates - a fast-curing material for the end fitting region and a slow-curing material for the core region. This parameter change enables the formation of a strong integrated bond between the end fitting and composite core during the manufacturing process itself, without requiring additional bonding steps or mechanical fasteners.
Solution Approach 2:
By employing composite materials with differential curing characteristics, the patent achieves both manufacturing simplicity and bonding strength. The materials are applied in sequence with different cure rates, allowing the end fitting to set quickly while the core cures slowly, creating a strong integrated structure in a single manufacturing process without complex assembly steps.
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
This solution enhances the bonding strength between the composite core and metallic end fittings, improving the drive shaft's durability and reducing weight by eliminating the need for mechanical connectors, thus providing improved functionality and viability.
Implementation Method 1
one or more structural adhesives are applied over the one or more fibres of the composite drive shaft and allowed to cure
Data Source
AI summary
A composite shaft assembly including a core structure formed by weaving fiber(s) into an open composite structure. The assembly further includes a first end piece and a second end piece having helically shaped groove(s) and/or axially groove(s) on an outer surface of an end portion of the first and second end piece. Woven into the helical and/or axial groove(s) on the first end piece and at least partially within through hole(s) disposed at an end of the groove(s) is the fiber(s) at a first end portion of the of the core structure. Woven into the helical and/or axial groove(s) on the second end piece and at least partially within through hole(s) disposed at an end of the groove(s) is the fiber(s) at a second end portion of the of the core structure. Structural adhesive(s) are applied over the fiber(s) and allowed to cure to form the composite drive shaft.