Composite Transmission Shaft With Integrated Flanged End Fitting
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Solution Overview
Problem
Metallic flanged end fittings in transmission shafts for high lift actuation systems are heavy, increasing weight in aircraft, and while composite materials reduce weight, they complicate manufacturing and may not adequately address structural and mechanical property requirements.
Innovation Solution
A composite transmission shaft formed entirely of composite material, where the flanged end fitting is integrally formed with the shaft portion using resin transfer moulding, with reinforcement portions and holes aligned for bolt connection, reducing weight and manufacturing complexity while maintaining mechanical properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If metallic flanged end fittings are used in transmission shafts, then structural and mechanical properties for transmitting torsional loads are achieved, but weight of the system increases
Solution Approach 1:
The patent changes the material parameter from metallic to composite material for the flanged end fitting, while maintaining the structural functionality. The composite material (fibres embedded in matrix) provides sufficient mechanical strength for torsional load transmission while significantly reducing the weight compared to traditional metallic materials.
Solution Approach 2:
The patent employs composite materials consisting of fibres embedded in a matrix material for the flanged end fitting. This composite structure provides the necessary mechanical properties for transmitting torsional loads without the weight penalty of metallic materials, directly resolving the contradiction between strength and weight.
2Weight of moving object
If the flanged portion is formed integrally with the shaft portion by winding fibres about a mandrel with a flared part, then weight is reduced, but manufacturing complexity increases
Solution Approach 1:
The patent divides the flanged end fitting into separate functional components: a tubular portion for connection to the shaft and a flanged portion with holes for bolts. These portions are formed separately using different manufacturing approaches and then joined, simplifying the overall manufacturing process compared to forming the entire structure in one complex integral operation.
Solution Approach 2:
The patent introduces a mandrel as an intermediary tool during the fabrication process. The mandrel is used to form the flanged portion with the necessary holes and geometry, and is subsequently removed. This intermediary approach simplifies the manufacturing of complex flanged geometries compared to direct forming methods.
3Ease of operation
If metal eyelets are inserted into holes after winding and curing, then bolt connection capability is achieved, but manufacturing complexity and weight increase
Solution Approach 1:
The patent incorporates the holes for bolt connections directly into the flanged portion during the initial fibre winding and curing process, rather than creating them as a separate post-processing step. This preliminary action integrates the connection feature into the main manufacturing flow, reducing overall manufacturing complexity and eliminating the need for separate eyelet insertion operations.
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 solution results in a lightweight, cost-effective, and structurally robust all-composite transmission shaft that optimizes torsional load transmission and reduces manufacturing complexity, negating the need for drilling in cured laminates and minimizing weight addition.
Implementation Method 1
The flanged end fitting and shaft portion have been resin transfer moulded together to form the transmission shaft
Data Source
Figure 1
Figure 2
AI summary
There is provided a composite transmission shaft 100, comprising a shaft portion 110, and a flanged end fitting 120. The flanged end fitting 120 comprises a flared sleeve 121 comprising a tubular portion 122 and a flared portion 124, and a reinforcement portion 126, 128 fixed to the flared portion 124 of the sleeve 124. The flanged end fitting 120 and shaft portion 110 have been resin transfer moulded together to form the transmission shaft 100. There is also provided a method of manufacturing such a composite transmission shaft 100 comprising providing a sleeve 121 which is substantially tubular; deforming an end of the sleeve to form a flared portion 124; fixing a reinforcement portion 126, 128 to the flared portion 124 of the sleeve 124 to form a preform of the flanged end fitting 124 comprising a tubular portion 122 and a flange; positioning the tubular portion 122 of the flanged end fitting 120 in contact with the shaft portion 110; and resin transfer moulding the shaft portion 110 and the flanged end fitting 120 together to form the transmission shaft 100.