Landing Gear Flexible Interface for Wheel Deformation Isolation
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Solution Overview
Problem
Aircraft ground taxiing is inefficient due to high fuel consumption and brake wear, and existing systems for powering aircraft landing gear wheels during taxiing are laborious and costly, especially when main engine thrust is not feasible.
Innovation Solution
A drive system for aircraft landing gear featuring a pinion gear, driven gear, and a flexible interface with spherical joints and resilient members to isolate the drive system from wheel deformations, allowing for relative movement and torque transmission while accommodating axle bending, braking, and tyre loads.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If a rigid connection is used between the driven gear and the wheel, then the torque transmission is efficient, but the drive system is subjected to high stresses and wear due to wheel deformations under vertical and braking loads
Solution Approach 1:
The patent employs a flexible interface comprising multiple flexible coupling members connecting the driven gear to the wheel. Each coupling member includes a resilient element that can elastically deform to accommodate wheel deformations while maintaining torque transmission. This flexible connection reduces stress and wear on the drive system components compared to a rigid connection, while still efficiently transmitting torque from the driven gear to the wheel during ground taxiing operations
2Device complexity
If the driven gear is rigidly connected to the wheel, then the structural simplicity is maintained, but the misalignment and deformation caused by axle bending and tyre loads increase wear within the drive system
Solution Approach 1:
The patent divides the connection between the driven gear and the wheel into multiple discrete flexible coupling members distributed around the circumference of the wheel. Each coupling member independently accommodates local deformations and misalignments. This segmented approach provides wear protection through flexibility while maintaining relatively simple overall structure compared to a completely rigid integrated connection
3Object-generated harmful factors
If main engine thrust is used for ground taxiing, then the propulsion is available, but the fuel consumption is high due to poor propulsion efficiency at low power
Solution Approach 1:
The patent replaces the mechanical propulsion system (main engines) with an electric motor-driven gear system for ground taxiing operations. The electric motor drives the pinion gear which meshes with the driven gear to rotate the wheel, substituting the engine-thrust-mechanical-propulsion chain with an electrical-mechanical drive system. This substitution enables efficient low-speed taxiing without the high fuel consumption associated with running main engines at low power
4Speed
If wheel brakes are applied to limit ground taxi speeds, then the speed control is achieved, but the brake wear increases significantly
Solution Approach 1:
The patent replaces the brake-based speed control mechanism with an electric motor-controlled drive system. The electric motor can precisely control wheel rotation speed through electrical control, eliminating or significantly reducing the need for mechanical brakes. This substitution reduces brake wear while maintaining effective ground taxi speed control during autonomous taxiing operations
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 flexible interface reduces wear and stress on the drive system and wheel, enabling efficient and reliable power transmission to the landing gear wheels, thus minimizing fuel consumption and brake wear, and allowing for autonomous taxiing without laborious tow truck operations.
Implementation Method 1
each driven gear coupling member comprises a resilient member arranged to bias the first connection portion towards the wheel axis
Implementation Method 2
The joint preferably comprises a spherical joint to provide rotational movement between the first and second connection portions, preferably rotational movement with three or more degrees of freedom
Data Source
Figure 1A~1C
Figure 2
Figure 3
AI summary
A drive system for an aircraft landing gear, the drive system comprising: a pinion gear (110); a drive shaft (120) arranged to rotate the pinion gear about a drive axis; a driven gear (130) arranged to mesh with the pinion gear to be rotatable by the pinion gear, the driven gear being connectable to a wheel of the landing gear to be capable of rotating the wheel about a wheel axis; and a flexible interface. The flexible interface comprises a plurality of driven gear coupling members (400), each driven gear coupling member having a first connection portion attached to the driven gear, a second connection portion adapted to be attached to the wheel at an offset distance from the wheel axis, and a joint between the first connection portion and the second connection portion, the joint permitting relative movement between the first connection portion and the second connection portion.