Actuator Arrangement Jam Protection Differential Gearbox
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The existing actuator arrangements for aircraft thrust reverser cowls are prone to damage due to jamming, particularly when electrically powered actuators are used, as they cannot withstand the high aerodynamic forces transmitted during deployment, leading to potential buckling of screw shafts.
Innovation Solution
An actuator arrangement featuring a pair of screw actuators driven by a common motor through a differential gearbox with a protection mechanism that senses jam conditions using sensors or a tie arrangement to prevent continued drive application to the jammed actuator, thereby reducing the risk of damage by distributing torque unequally and applying locks to prevent further movement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Weight of moving object
If electrically powered actuators are used to reduce weight, then weight is reduced, but the actuators cannot withstand high aerodynamic forces during deployment
Solution Approach 1:
The patent applies beforehand cushioning by designing a protection arrangement that anticipates potential jamming conditions. Sensors detect abnormal conditions before damage occurs, and the control system prepares to interrupt drive or apply locks in advance, cushioning the actuator against the full force of aerodynamic loads that would otherwise cause buckling during deployment
2Stability of the object's composition
If a tie arrangement is used to resist relative rotation of drive shafts, then synchronisation is improved, but the system becomes vulnerable to excessive torque during jamming
Solution Approach 1:
The patent applies dynamics by making the tie arrangement's mechanical properties changeable. The tie arrangement is designed with controlled flexibility or yield characteristics, allowing it to transition from a rigid synchronising element to a compliant element that can yield or disconnect under excessive torque, thus adapting its behavior based on operational conditions
Solution Approach 2:
The protection arrangement acts as an intermediary between the tie arrangement and the actuators. When the tie arrangement experiences excessive torque, the protection arrangement (including sensors and control systems) mediates by detecting the condition and interrupting drive or applying locks, preventing the full force from reaching the actuators
3Reliability
If drive is interrupted to protect the actuator, then actuator damage is prevented, but system complexity increases
Solution Approach 1:
The patent applies self-service by designing a protection arrangement that automatically detects and responds to jamming conditions without external intervention. Sensors continuously monitor actuator conditions, and the control system automatically interrupts drive or applies locks when abnormalities are detected, making the system self-protecting and reducing the need for complex external monitoring systems
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 solution effectively reduces the risk of actuator damage by interrupting drive to the jammed actuator and distributing aerodynamic forces, ensuring continued operation of the system without increasing size or weight, thus enhancing the robustness of electrically powered thrust reverser systems.
Implementation Method 1
the motor is arranged to drive the drive shafts through a differential gearbox
Implementation Method 2
senses jam conditions using sensors
Implementation Method 3
applying locks to prevent further movement
Data Source
Figure 1
Figure 2
AI summary
An actuator arrangement comprises a pair of symmetrically loaded screw actuators (14) driven from a common motor (22) through respective drive shafts (20), and a protection arrangement (36, 40) arranged to avoid the continued application of full motor drive to one of the actuators (14) in the event of the occurrence of a jam condition on associated therewith.