Hybrid Star Worm Gear for High-Speed Thrust Reverser Actuation
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Solution Overview
Problem
Conventional thrust reverser actuators face challenges with high rotational speeds exceeding the design limits of synchronization shafts due to advancements in thrust reverser technology, necessitating newer rotary-to-linear motion conversion technologies that are compact, lightweight, and compatible with existing designs.
Innovation Solution
The implementation of a hybrid worm gear and epicyclic gearbox assembly, where the ring gear functions as both the worm wheel and planetary gearbox, providing a compact design for rotary-to-linear motion conversion, enabling gear reduction and synchronization of thrust reverser actuation systems with high-speed synchronization shafts.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If conventional back-driven worm gears are used, then the actuators can be synchronized, but the rotational speeds exceed the shaft manufacturer's maximum design speed
Solution Approach 1:
The patent combines a worm gear mechanism with an epicyclic gear assembly into a single integrated drive unit. The worm gear provides speed reduction while the epicyclic gears provide additional reduction and torque multiplication, allowing the synchronization shaft to operate within its design speed limits while still achieving the required actuation speeds.
Solution Approach 2:
The epicyclic gear assembly acts as an intermediary between the high-speed worm gear input and the lower-speed output required by the synchronization shaft. This intermediate stage reduces the speed progressively, preventing the shaft from exceeding its maximum design speed while maintaining the benefits of worm gear self-locking and synchronization.
2Productivity
If a hybrid worm gear and epicyclic gearbox assembly is implemented, then gear reduction and synchronization are achieved, but the device complexity increases
Solution Approach 1:
The patent merges the worm gear and epicyclic gear mechanisms into a single compact assembly where the worm wheel serves as the ring gear of the epicyclic system. This integration reduces the number of separate components and simplifies the overall structure while maintaining the compound gear reduction capability.
Solution Approach 2:
The ring gear component serves dual functions: it acts as the worm wheel for the worm gear mechanism and simultaneously serves as the outer ring gear for the epicyclic gear assembly. This multi-functionality reduces the total number of parts needed while achieving the required gear reduction ratios.
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
This solution provides a compact, space-saving, and weight-efficient system capable of handling high-speed synchronization, reducing mechanical inefficiencies and allowing thrust reverser actuation systems to operate effectively with advanced technologies while minimizing impact on existing designs.
Implementation Method 1
a worm drive assembly having a worm shaft, and a worm wheel configured as a ring having a radially outer perimeter comprising a first collection of gear teeth extending radially outward from the radially outer perimeter and at least partly engaged with the worm shaft
Implementation Method 2
an epicyclic gear assembly having a sun gear and a planet gear engaged with the sun gear and the second collection of gear teeth
Implementation Method 3
a linear actuator assembly having a leadscrew engaged to the sun gear and responsive to revolution of the sun gear, and a nut engaged with the leadscrew and axially movable along the leadscrew in response to rotation of the leadscrew
Data Source
AI summary
The subject matter of this specification can be embodied in, among other things, an actuator that includes a worm drive assembly having a worm shaft, and a worm wheel configured as a ring having a radially outer perimeter comprising a first collection of gear teeth extending radially outward from the radially outer perimeter and at least partly engaged with the worm shaft, and a coaxial radially inner perimeter comprising a second collection of gear teeth extending radially inward from the inner perimeter, and an epicyclic gear assembly having a sun gear and a planet gear engaged with the sun gear and the second collection of gear teeth.