Landing Gear Hubcap Gear Reduction for High-Torque Aircraft Taxiing
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Solution Overview
Problem
Autonomous taxiing systems for aircraft require high torque output, which is typically achieved by large and heavy motors, and existing solutions introduce additional rotating components that can fail and cause retarding torque during takeoff, increasing maintenance and noise concerns.
Innovation Solution
A landing gear system with a planetary gear assembly and a clutch assembly that selectively engages and disengages the ring gear with the wheel, using a compact motor to convert high-speed/low-torque input into low-speed/high-torque output, and includes a clutch assembly with sliding clutch portions and alignment features to ensure proper engagement and disengagement without introducing additional failure modes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If large and heavy motors are used to deliver high torque for aircraft taxiing, then the required torque output is achieved, but the motor size and weight increase
Solution Approach 1:
The motor function is segmented into two separate components: a compact high-speed motor and a planetary gear assembly. The motor provides high-speed rotation while the gear assembly provides mechanical advantage to generate high torque, eliminating the need for a single large heavy motor.
Solution Approach 2:
The planetary gear assembly acts as an intermediary between the compact motor and the wheel. It transforms the motor's high-speed/low-torque output into low-speed/high-torque output suitable for driving the aircraft wheel during taxiing.
2Adaptability or versatility
If additional rotating components are added to the landing gear for autonomous taxiing, then drive capability is provided, but the risk of retarding torque during takeoff increases
Solution Approach 1:
The clutch assembly extracts and isolates the autonomous taxi drive system from the wheel during takeoff operations. By disengaging the clutch, the planetary gear assembly and drive shaft are disconnected from the wheel, eliminating the risk of retarding torque during critical takeoff acceleration.
Solution Approach 2:
The clutch assembly provides dynamic engagement and disengagement of the drive system. It can be engaged during taxiing to provide drive capability and disengaged during takeoff to eliminate potential failure modes, adapting the system state based on operational requirements.
3Weight of moving object
If compact lightweight motors are used for aircraft, then motor size and weight are reduced, but the torque output becomes insufficient
Solution Approach 1:
The planetary gear assembly serves as a mechanical intermediary that amplifies the torque output of the compact motor. Through the gear reduction mechanism, the motor's high-speed/low-torque rotation is converted into low-speed/high-torque rotation sufficient for aircraft taxiing.
Solution Approach 2:
The function of torque generation is segmented from the motor itself and transferred to the planetary gear assembly. This allows the motor to be optimized for weight and size while the gear assembly handles the torque multiplication function.
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 effectively provides the necessary torque for aircraft taxiing while minimizing additional rotating components, reducing maintenance and noise, and ensuring safe operation by isolating the planetary gear assembly from the wheels during disengagement.
Implementation Method 1
a planetary gear assembly having a sun gear operably coupled to the drive shaft and a planet gear operably engaging the sun gear. A ring gear surrounds and is operably coupled to the planet gear such that rotation of the drive shaft rotates the ring gear.
Implementation Method 2
A clutch assembly is selectively moveable between an engaged state and a disengaged state. The clutch assembly transfers rotation of the ring gear to the wheel when the clutch assembly is in the engaged state, and the clutch assembly does not transfer rotation of the wheel to the ring gear when the clutch assembly is in the disengaged state.
Data Source
AI summary
A landing gear system includes wheel rotatably coupled to an axle. A driveshaft extends through a cavity formed in the axle and is rotatable about an axis. A planetary gear includes a sun gear operably coupled to the drive shaft and a planet gear operably engaging the sun gear. The planetary gear further includes a ring gear that surrounds and is operably coupled to the planet gear so that rotation of the drive shaft rotates the ring gear. A clutch assembly is selectively moveable between an engaged state and a disengaged state. The clutch assembly transfers rotation of the ring gear to the wheel when the clutch assembly is in the engaged state, and the clutch assembly does not transfer rotation of the wheel to the ring gear when the clutch assembly is in the disengaged state.