Captive Connecting Ring for Aircraft Drive Shaft Dismantling
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Solution Overview
Problem
Existing aircraft turbine engine drive line shafts require complete disassembly and reassembly for maintenance due to inaccessible connecting rings, which is time-consuming and complex, especially when the reduction gear shaft has a reduced diameter.
Innovation Solution
A captive connecting ring system within a main shaft, featuring front and rear retaining members that allow the connecting ring to be accessed and rotated from the front, enabling disassembly and assembly without external access, using tools inserted through the main shaft's interior cavity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the connecting ring is positioned downstream at a distance of more than one meter from the upstream end of the low-pressure drive line, then the shafts can be securely connected, but the connecting ring becomes inaccessible for maintenance operations
Solution Approach 1:
The connecting ring is nested within the hollow interior cavity of the low-pressure drive line shafts, allowing it to be positioned at the downstream location needed for secure connection while remaining accessible through the hollow interior for maintenance operations. This nesting approach resolves the contradiction by providing both secure connection and maintenance accessibility.
2Area of moving object
If the reduction gear shaft diameter is reduced to minimize radial size, then the radial footprint is reduced, but the shaft becomes too narrow to allow passage of the connecting ring during maintenance
Solution Approach 1:
The connecting ring is nested within the hollow interior of the reduction gear shaft, allowing the shaft to have a reduced external diameter while still providing sufficient internal space for the connecting ring. This enables both compact radial size and maintenance accessibility.
Solution Approach 2:
Instead of passing the connecting ring through the shaft from the outside, the approach is inverted by inserting the connecting ring through the hollow interior of the shaft from the upstream end, allowing maintenance access while maintaining reduced external dimensions.
3Ease of repair
If complete disassembly and reassembly of the low-pressure drive line is performed for maintenance, then the turbine shaft can be accessed, but the maintenance operation becomes time-consuming
Solution Approach 1:
The drive line is segmented into modular components (reduction gear shaft, compressor shaft, turbine shaft) connected by removable connecting rings. This allows the turbine shaft to be accessed by removing only the relevant connecting ring rather than disassembling the entire drive line, significantly reducing maintenance time.
Solution Approach 2:
The connecting ring is extracted as a separate removable component that can be independently removed from the hollow interior of the drive line during maintenance, allowing access to the turbine shaft without disassembling other parts of the drive line.
Data Source
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AI summary
Disclosed is a main shaft (1) for an aircraft turbine engine drive line (A) extending longitudinally from front to rear along an axis (X) and comprising a rear portion (10) configured for receiving a front portion (20) of a rear shaft (2) by interlocking, the main shaft (1) comprising: - a front retaining member (6) and a rear retaining member (11) together defining a prison (13) and each comprising a central opening, - a connecting ring (4), located in the prison (13), comprising a rear end configured to be screwed to a front end (21) of the rear shaft (2) extending into the central opening of the rear retaining member (11), the connecting ring (4) comprising a gripping member formed on the inner surface and accessible from a front portion (14) of the main shaft (1) by a tool extending via the central opening of the front retaining member (6).