Dual-Path Shaft Coupling for Misalignment-Tolerant Torque Backup
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Solution Overview
Problem
Existing torque transmission systems in vehicles, such as aircraft, are prone to blocking due to misalignment of the drive shaft with respect to the axis of rotation following accidental ruptures or bearing failures, leading to system failure.
Innovation Solution
A multiple path torque transmission system with a hollow drive shaft and a driven shaft, featuring a nominal splined connection and an emergency splined connection, along with an emergency radial guide device, which remain inactive during nominal operation but become functional in degraded modes to maintain torque transmission and radial guidance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a single torque transmission path is used between drive shaft and driven shaft, then the structure is simple, but the system blocks after accidental rupture or bearing failure
Solution Approach 1:
The torque transmission system is divided into multiple independent paths: a primary path (drive shaft → large wheel → driven shaft) and a secondary path (drive shaft → emergency connection → driven shaft). When the primary path fails due to bearing rupture or shaft breakage, the secondary path remains functional and can sustain torque transmission, ensuring system continuity without requiring complete system redesign
Solution Approach 2:
The emergency splined connection is pre-positioned above the nominal connection in the drive shaft, with splines already formed and ready for engagement. In the event of primary path failure, the drive shaft can automatically shift upward to engage the emergency connection without requiring complex activation mechanisms, enabling immediate failover to the secondary transmission path
2Reliability
If emergency connection components are always engaged, then immediate backup is available, but premature wear occurs during nominal operation
Solution Approach 1:
The emergency splined connection is designed to be dynamically engageable and disengageable along the axial direction of the drive shaft. During normal operation, the emergency connection remains disengaged (positioned above the nominal connection) to avoid wear. Upon detection of primary path failure or automatic mechanical triggering, the drive shaft shifts axially to engage the emergency connection, providing backup functionality only when needed and maximizing component service life
3Reliability
If the drive shaft is solid, then the structure is simple, but rupture causes complete system failure
Solution Approach 1:
The drive shaft is designed as a hollow shaft with multiple functional sections: lower guide section, intermediate section with nominal connection, and upper guide section with emergency connection. This segmented hollow structure allows the shaft to potentially fail in one section while maintaining integrity and functionality in other sections, enabling the emergency path to remain operational even after partial shaft rupture
Solution Approach 2:
The hollow drive shaft incorporates the emergency splined connection pre-formed in the upper guide section, ready for automatic engagement if the lower or intermediate sections fail. The hollow structure also provides space for potential reinforcement elements or sensors that can detect shaft integrity issues and trigger emergency path engagement
4Reliability
If bearing guidance is the only radial guidance method, then the structure is simple, but bearing failure causes misalignment and blocking
Solution Approach 1:
The radial guidance system is segmented into primary guidance (bearings at lower and upper guide sections) and secondary guidance (emergency radial guide device with guide splines). The emergency radial guide device includes multiple guide splines distributed around the circumference that can independently support the drive shaft radially, providing distributed guidance that maintains alignment even if some guide elements fail
Solution Approach 2:
The emergency radial guide device is pre-positioned to engage automatically when bearing guidance fails. The guide splines are pre-formed with appropriate clearance to allow normal bearing operation, but will engage radially to prevent misalignment if bearing rupture occurs, maintaining shaft alignment without requiring complex sensing or activation systems
Data Source
Figure 1
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Figure 3
AI summary
The present invention relates to a multi-path torque transmission system (1) between a driving shaft (10) and a driven shaft (20). The driving shaft extends from a lower section (11) to an upper section (15) via an intermediate section (12), the driven shaft (20) extending from a first section (21) to a second section (22). The transmission system (1) comprises a nominal splined linkage (30) functional in nominal operation, a backup splined linkage (40) between the driving shaft (10) and the driven shaft (20) which is inactive in nominal operation, and a backup radial guide device (50) between the driving shaft (10) and the driven shaft (20) which is inactive in nominal operation.