Gerotor Ball Screw Actuator Locking for Thrust Reversers
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Solution Overview
Problem
Existing thrust reverser systems for gas turbine engines require an additional motor to drive multiple flexshafts, increasing weight and space requirements around the thrust reverser.
Innovation Solution
An actuator system for a thrust reverser that includes a ball screw coupled to a gerotor, eliminating the need for an additional motor by using a lock system to control the rotation of the ball screw, allowing the thrust reverser to move between multiple positions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If multiple flexshafts are used to move the thrust reverser, then the thrust reverser can be driven effectively, but an additional motor is required which increases weight and space requirements
Solution Approach 1:
The patent combines the motor and ball screw actuator into a single integrated unit mounted directly on the thrust reverser. The motor drives the ball screw through a gerotor mechanism, eliminating the need for separate flexshaft drive systems. This merging of functions reduces the overall component count, removes the need for additional motors, and decreases both weight and space requirements while maintaining reliable thrust reverser operation.
Solution Approach 2:
The patent introduces a gerotor mechanism as an intermediary between the motor and ball screw. The gerotor converts the motor's rotational output into the appropriate motion to drive the ball screw, enabling direct mounting on the thrust reverser without requiring external flexshaft connections. This intermediary mechanism facilitates the integration of the drive system into a compact, self-contained unit.
2Reliability
If multiple flexshafts are used to move the thrust reverser, then the thrust reverser can be driven effectively, but an additional motor is required which increases space requirements
Solution Approach 1:
The patent combines the motor and ball screw actuator into a single integrated unit mounted directly on the thrust reverser. The motor drives the ball screw through a gerotor mechanism, eliminating the need for separate flexshaft drive systems. This merging of functions reduces the overall component count, removes the need for additional motors, and decreases both weight and space requirements while maintaining reliable thrust reverser operation.
Solution Approach 2:
The patent employs a nested arrangement where the ball screw is received within an extension shaft, and the gerotor mechanism is integrated within the actuator housing. This nesting of components allows the entire drive system to be compacted into a space-efficient configuration that can be directly mounted on the thrust reverser without requiring additional external space for separate motor and transmission components.
3Ease of operation
If a lock system is added to control ball screw rotation, then positional control is improved, but device complexity increases
Solution Approach 1:
The lock system is designed to automatically engage and disengage based on the position of the thrust reverser. The system uses the existing motion of the ball screw and gerotor mechanism to trigger locking at predetermined positions, eliminating the need for external actuators or complex control systems. This self-service approach provides reliable positional control while minimizing additional complexity by leveraging the existing mechanical motion rather than requiring separate locking actuators.
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 actuator system reduces the weight and space requirements of the thrust reverser by eliminating the need for an additional motor, while also enabling efficient movement between multiple positions.
Implementation Method 1
a ball screw configured to be coupled to the thrust reverser, and a ball nut coupled to the ball screw
Implementation Method 2
a gerotor coupled to the ball screw. The gerotor includes an inner rotor coupled to the ball screw and an outer rotor
Implementation Method 3
The piston housing includes a piston spring and a fitting, the piston includes a head and a shaft, the shaft is configured to engage the one of the plurality of bores of the outer rotor and the piston spring is disposed between the head and the fitting to bias the piston into engagement with the one of the plurality of bores of the outer rotor
Data Source
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AI summary
An actuator for a thrust reverser includes a ball screw, a ball nut coupled to the ball screw, and a gerotor coupled to the ball screw. The gerotor includes an inner rotor coupled to the ball screw and an outer rotor. The outer rotor includes a plurality of bores. The actuator includes a lock system coupled to the outer rotor. The lock system is to enable the gerotor to rotate the ball screw in an unlocked state and to inhibit a rotation of the ball screw in a lock state. The lock system includes a piston coupled to a piston housing and a grippable member coupled to the piston housing. The piston is received in one of the bores in the lock state, and the grippable member is to move the piston housing relative to the gerotor to move the lock system to the unlocked state.