Multi-Path Torque Coupling for Rotorcraft Jam Tolerance
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Solution Overview
Problem
Existing torque transmission systems in rotorcrafts are prone to jamming due to accidental breakage of bearings or segments, leading to misalignment of the driving shaft with the axis of rotation.
Innovation Solution
A torque transmission system with a hollow driving shaft and a driven shaft, featuring a nominal spline coupling and a backup spline coupling, as well as a backup radial guide device, which remain inactive in nominal operating mode but become operational in degraded modes to maintain torque transmission and guidance, providing multiple pathways for operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a single torque transmission pathway is used, then the device complexity is reduced, but the reliability decreases due to jamming risk from bearing or segment breakage
Solution Approach 1:
The torque transmission system is divided into multiple independent pathways: a primary pathway (driving shaft → driven shaft) and at least one alternative pathway (driving shaft → intermediate element → driven shaft). This segmentation allows the system to switch pathways when one fails, resolving the contradiction by improving reliability through redundancy while maintaining manageable complexity through modular design.
Solution Approach 2:
The system changes the operational parameter from single-pathway torque transmission to multi-pathway torque transmission. By introducing alternative transmission routes with different structural parameters (different gears, shafts, or coupling mechanisms), the system achieves improved reliability without proportionally increasing overall complexity, as the alternative pathways use similar component types.
2Reliability
If backup torque transmission pathways are added, then the reliability improves, but the device complexity increases
Solution Approach 1:
The alternative torque transmission pathways are designed to perform the same fundamental function as the primary pathway: transmitting torque from the driving shaft to the driven shaft. By using universal component types (gears, shafts, couplings) that serve multiple functions across different pathways, the system achieves improved operation continuity while minimizing the increase in component complexity through design standardization.
3Reliability
If multiple torque transmission pathways are implemented, then the reliability is improved, but the manufacturing precision requirements increase
Solution Approach 1:
By segmenting the torque transmission into independent pathways with distinct mechanical interfaces, the system isolates precision requirements to individual coupling points rather than requiring high precision across the entire transmission chain. Each pathway can be manufactured and assembled independently with standard precision tolerances, reducing overall manufacturing complexity while maintaining system robustness.
Data Source
AI summary
A torque transmission system having multiple torque transmission pathways from a driving shaft to a driven shaft. The driving shaft extends from a lower segment to an upper segment via an intermediate segment, the driven shaft extending from a first segment to a second segment. The transmission system includes a nominal spline coupling that is operational in a nominal operating mode, a backup spline coupling between the driving shaft and the driven shaft that is inactive in the nominal operating mode, and a backup radial guide device between the driving shaft and the driven shaft that is inactive in the nominal operating mode.