Integrated Torque Sensing for No-Back Friction Drive Shafts
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Solution Overview
Problem
High lift systems in aircraft require frequent inspection of friction disc arrangements to maintain safety, which is inefficient and increases system complexity.
Innovation Solution
A drive system incorporating a torque sensing device, a no-back friction unit with a one-way clutch and friction discs, and an axial bearing, which allows free rotation during extension and generates a friction-induced torque during retraction, enabling detection of torque deviations and reducing the need for frequent inspections.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a friction disc arrangement is used in the no-back device, then safety is maintained by preventing the actuator from being pushed back, but frequent inspection is required and system complexity increases
Solution Approach 1:
A torque sensing device is integrated into the drive system to continuously monitor the torque transferred from the drive unit to the shaft. This feedback mechanism detects torque deviations that indicate potential failures in the no-back friction unit, enabling condition-based monitoring that reduces the need for frequent manual inspections while maintaining safety
Solution Approach 2:
The patent replaces the need for mechanical inspection of the friction disc arrangement with a torque sensing system. Instead of physically examining the friction discs, the system uses torque measurement to indirectly assess the condition of the no-back device, simplifying the inspection process while maintaining reliability
2Reliability
If the no-back friction unit applies friction-induced torque during retraction, then safety is maintained, but the drive unit must work against additional resistance
Solution Approach 1:
The no-back friction unit is designed to apply friction-induced torque only during retraction (opposite second direction of rotation), not during extension. This partial application of friction force provides safety when needed while minimizing the impact on drive power during the extension phase where safety is less critical
3Reliability
If the friction disc arrangement is regularly inspected, then safety is maintained, but inspection time and operational downtime increase
Solution Approach 1:
The torque sensing device provides continuous feedback on the operational condition of the no-back friction unit by monitoring torque deviations. This real-time monitoring enables predictive maintenance, allowing inspections to be scheduled based on actual condition rather than fixed intervals, thereby reducing total inspection time and operational downtime
Solution Approach 2:
The torque sensing device detects potential failures before they occur by monitoring torque deviations that indicate deteriorating condition of the friction disc arrangement. This preliminary detection allows maintenance to be performed at optimal times rather than through frequent scheduled inspections, reducing overall inspection time
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 system maintains safety by detecting potential failures and reducing the need for frequent inspections, eliminating the requirement for a wing tip brake, thereby simplifying the system and reducing weight.
Implementation Method 1
the no-back friction unit is designed to substantially not counteract a rotation of the shaft in a first direction of rotation of the shaft and to apply a friction-induced additional torque to the shaft in an opposite second direction of rotation
Data Source
AI summary
A drive system for driving a movable flow body having a drive unit, a shaft, a torque sensing device, a no-back friction unit, and an axial bearing. The drive unit is coupled with the shaft to rotate the shaft, the torque sensing device is coupled with at least one of the drive unit and the shaft to detect a torque transferred from the drive unit into the shaft, the no-back friction unit is arranged between the axial bearing and an axial support means of the shaft, such that an axial load of the shaft is supported by the axial bearing, and the no-back friction unit is configured to substantially not counteract a rotation of the shaft in a first direction of rotation of the shaft and to apply a friction-induced additional torque to the shaft in an opposite second direction of rotation.