Concentric Ballscrew Actuator for Short-Envelope Thrust Reversers
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Solution Overview
Problem
Aerospace thrust reverser actuation systems require increased stow and deploy strokes within a smaller installation envelope while maintaining performance, which existing single ballscrew actuators fail to achieve efficiently.
Innovation Solution
A telescopic ballscrew actuator system with two concentric ballscrew mechanisms, allowing for both translational and rotational movements, enabling sequential modes of operation to achieve defined actuator strokes within a reduced installation length.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If a single ballscrew actuator is used, then the structure is simple, but the installation envelope is too large and the stroke is insufficient
Solution Approach 1:
The patent implements a telescopic ballscrew actuator where one ballscrew mechanism is nested within another. The inner ballscrew (second mechanism) is positioned concentrically within the outer ballscrew (first mechanism), allowing both mechanisms to occupy the same radial space. This nesting arrangement reduces the overall installation envelope length while providing combined strokes from both mechanisms, directly resolving the contradiction between compact size and sufficient stroke.
Solution Approach 2:
The actuator is divided into two separate ballscrew mechanisms that operate independently but contribute to the same output motion. Each ballscrew mechanism has its own screw thread, nut, and control system, allowing the total stroke to be the sum of both mechanisms' strokes. This segmentation enables the actuator to achieve longer effective stroke within a compact installation envelope.
2Length of moving object
If the stow and deploy strokes are increased, then the performance is improved, but the installation envelope size increases
Solution Approach 1:
By nesting the second ballscrew mechanism within the first, the patent achieves combined strokes from both mechanisms without proportionally increasing the installation envelope length. The concentric arrangement allows the outer diameter to remain determined by the larger of the two mechanisms rather than the sum of both, thus providing increased stroke capability within a compact envelope.
Solution Approach 2:
The patent transitions from a single linear dimension of stroke to a two-dimensional configuration where two ballscrew mechanisms operate in parallel within the same radial space. This dimensional arrangement allows the effective stroke to be increased by combining the travel of both mechanisms while maintaining a compact installation envelope length.
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 telescopic ballscrew actuator system fits into a shorter installation envelope compared to conventional systems, offering size benefits while maintaining performance characteristics, and allowing for efficient thrust reverser operation in aerospace applications.
Implementation Method 1
a first ballscrew mechanism between the input shaft and the first component, and configured such that rotational movement of the input shaft causes a translational movement of the first component via the first ballscrew mechanism
Implementation Method 2
a second ballscrew mechanism between the first component and the second component, and configured such that rotational movement of the first component causes a translational movement of the second component via the second ballscrew mechanism
Data Source
AI summary
An apparatus for a thrust reverser actuation system (“TRAS”), the apparatus comprising: an input shaft; a first component located concentrically around the input shaft; a second component located concentrically around the first component; a first balls crew mechanism between the input shaft and the first component, and configured such that rotational movement of the input shaft causes a translational movement of the first component via the first ballscrew mechanism; and a second ballscrew mechanism between the first component and the second component, and configured such that rotational movement of the first component causes a translational movement of the second component via the second ballscrew mechanism.