Wheel and Gear Assembly Radial Isolation Torque Transmission
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Solution Overview
Problem
Existing aircraft ground taxi systems face inefficiencies in propulsion, high fuel consumption, and brake wear due to limited traction and space constraints, particularly when using nose landing gears, which are insufficient for reliable ground taxiing and pre-landing wheel spin-up.
Innovation Solution
A wheel assembly with radial isolation of the ring gear from wheel rim deformations, allowing torque transmission through a radial clearance interface, and a drive system detachably mounted on main landing gear for efficient power transmission and control, incorporating a motor and constant-velocity joint to maintain engagement during deflections.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the ring gear is rigidly connected to the wheel rim, then torque transmission is strong, but the ring gear is subjected to deformations from the wheel rim under load
Solution Approach 1:
The connection between the ring gear and wheel rim is segmented into multiple discrete connection members (bolts, studs, or keys) distributed around the circumference. This segmentation allows the connection to accommodate local deformations while maintaining overall torque transmission integrity.
Solution Approach 2:
Connection members serve as intermediaries between the ring gear and wheel rim, providing a controlled interface that transmits torque while isolating the ring gear from direct deformation. The connection members can elastically deform or allow slight relative movement to absorb deformation stresses.
2Stability of the object's composition
If a radial clearance interface is provided between the wheel hub and ring gear, then the ring gear is isolated from wheel rim deformations, but torque transmission path is lengthened
Solution Approach 1:
The radial clearance interface is segmented into multiple discrete connection members distributed around the circumference. This segmentation allows the torque to be transmitted through multiple short paths rather than one long path, reducing the overall effect of the extended transmission distance.
Solution Approach 2:
The connection transitions from a direct radial interface to a circumferential array of connection members. This dimensional change allows torque to be transmitted through the circumferential distribution of connection members, effectively managing the extended path length.
3Area of stationary object
If nose landing gear is used for ground taxiing, then space requirements are reduced, but sufficient traction for reliable ground taxiing cannot be achieved
Solution Approach 1:
The mechanical system is replaced by providing a drive interface (ring gear and pinion gear) that enables powered ground taxiing. This substitution allows the aircraft to generate its own propulsion force, replacing the need for external tow trucks and providing sufficient traction through the driven wheels.
4Power
If main engines are run at low power for ground taxiing, then propulsion efficiency is poor, but fuel consumption increases
Solution Approach 1:
The propulsion function is segmented from the main engines to dedicated auxiliary power units (APUs) or electric motors. This segmentation allows the main engines to operate at efficient power levels while the auxiliary systems handle the low-power ground taxiing operations, improving overall fuel efficiency.
Solution Approach 2:
The auxiliary power units or electric motors provide multi-functionality by handling both ground taxiing propulsion and potential pre-landing wheel spin-up operations. This universal application optimizes energy use across different operational phases.
5Speed
If wheel brakes are applied to limit ground taxi speeds, then ground taxi speed control is achieved, but brake wear increases
Solution Approach 1:
The mechanical braking system is supplemented or replaced by a powered drive system with controlled acceleration and deceleration. The drive system can provide propulsive force for acceleration and regenerative braking or controlled power reduction for deceleration, reducing reliance on friction brakes and extending their service life.
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 enables reliable aircraft ground taxiing with reduced fuel consumption and brake wear by optimizing torque transmission and traction, allowing for efficient power delivery and maintenance flexibility.
Implementation Method 1
incorporating a motor and constant-velocity joint to maintain engagement during deflections
Implementation Method 2
The interface provides for radial isolation of the ring gear from deformations of the wheel rim while permitting torque to be transmitted through the interface
Data Source
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AI summary
A wheel assembly (600) is disclosed, in which a ring gear (700) is movably mounted to the rim of the wheel (601), so that torque can be transmitted between wheel and rim, while the ring gear is isolated from deformations induced in the wheel rim.