Integrated Torque Sensing for Self-Monitoring No-Back Drives
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Solution Overview
Problem
Existing high lift systems for aircraft require regular inspection of friction disc arrangements to maintain safety, which is time-consuming and increases maintenance costs.
Innovation Solution
A drive system comprising a drive unit, a shaft, a torque sensing device, a no-back friction unit with a one-way clutch and friction discs, and an axial bearing, where the no-back friction unit applies a friction-induced torque only during retraction, allowing for continuous operation without the need for regular inspection.
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 regular inspection is required which increases maintenance time and costs
Solution Approach 1:
The torque sensing device enables the no-back device to perform self-monitoring by detecting torque values and comparing them against threshold values. The system automatically identifies when friction disc wear exceeds acceptable limits, eliminating the need for manual inspections and allowing the system to service itself through continuous automated monitoring.
Solution Approach 2:
The torque sensing device provides continuous feedback about the torque transmitted through the friction disc arrangement. This feedback mechanism allows the control system to monitor the condition of the friction discs in real-time and trigger maintenance alerts when performance degradation is detected, replacing the need for periodic manual inspections.
2Reliability
If friction discs are used to provide mechanical resistance during retraction, then the actuator is protected from reverse movement, but the friction disc arrangement requires active engagement that increases device complexity
Solution Approach 1:
The torque sensing device is integrated directly into the drive system's torque transmission path, combining the monitoring function with the existing mechanical structure. This merging approach allows the sensing element to detect torque without requiring separate monitoring systems or additional mechanical components, thereby maintaining safety while reducing overall device complexity.
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 drive system reduces the need for regular inspection while maintaining or improving safety by integrating a self-checking mechanism that detects deviations in torque, preventing dormant failures and eliminating the need for a wing tip brake.
Implementation Method 1
The torque sensing element comprises a torsion spring having ends which are coupled to the input shaft and the output shaft for rotation therewith
Implementation Method 2
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
Figure 1~3
AI summary
A drive system for driving a movable flow body is proposed, comprising a drive unit, a shaft, a torque sensing device, a no-back friction unit, and an axial bearing, wherein the drive unit is coupled with the shaft to rotate the shaft, wherein 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, wherein 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 wherein 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.