Aircraft Control Surface Drive Link with Spherical Bearings
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Solution Overview
Problem
Aircraft control surface operating devices face challenges in handling significant forces during flight, often requiring bulky designs that compromise other aircraft features, and existing solutions do not adequately address the need for a compact and efficient mechanism to move control surfaces between retracted and extended positions.
Innovation Solution
The aircraft control surface operating device incorporates a drive arm rotatable about a drive axis, connected via a drive link with a drive bearing joint and a control bearing joint, allowing for rotational motion to be translated into retracting and extending forces on the control surface mounting assembly, with the drive link capable of movement in x, y, and z directions to accommodate lateral offsets and minimize stress.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional operating devices are designed to handle significant aerodynamic forces, then the device can reliably operate control surfaces during flight, but the device becomes bulky and compromises other aircraft features
Solution Approach 1:
The patent employs spherical bearings (both drive spherical bearing and control spherical bearing) to replace conventional pivot connections. The spherical bearings allow rotational movement in multiple directions while maintaining compact dimensions, enabling the drive link to accommodate lateral offsets and angular misalignments without requiring bulky adjustment mechanisms. This curved/spherical geometry resolves the contradiction by providing reliable force transmission through the aerodynamic loads while maintaining a compact device volume.
Solution Approach 2:
The patent changes the geometric parameters of the connection mechanism by introducing non-parallel axis arrangements. Specifically, the axis of rotation of the drive link is made non-parallel to the imaginary line connecting the drive bearing connecting portions, and the axis of rotation about the control bearing is made parallel to the imaginary line connecting the control bearing connecting portions. This parameter change allows the mechanism to accommodate lateral offsets and minimize stress concentrations, enabling compact design while maintaining reliability under aerodynamic forces.
2Volume of moving object
If the operating device is designed to be compact, then other aircraft features are preserved, but the device may struggle to handle significant forces during flight
Solution Approach 1:
The spherical bearings provide compact connections that can handle significant forces. The spherical geometry allows the bearings to accommodate lateral offsets and angular misalignments while maintaining reliable force transmission through the aerodynamic loads. The spherical shape distributes stresses more evenly across the bearing surfaces, enabling compact design without sacrificing force handling capability.
Solution Approach 2:
The non-parallel axis arrangement changes the geometric parameters to optimize force transmission. By making the drive link's axis of rotation non-parallel to the line connecting the drive bearing connecting portions, and the control bearing's axis of rotation parallel to the line connecting its connecting portions, the mechanism minimizes stress concentrations and efficiently transmits aerodynamic forces through the compact structure.
3Power
If rigid connections are used in the operating device, then force transmission is efficient, but stress on connection points increases
Solution Approach 1:
The spherical bearings replace rigid fixed-axis connections with flexible spherical joints. These spherical connections maintain efficient force transmission while accommodating lateral offsets and angular misalignments through their rotational degrees of freedom. The spherical geometry distributes stresses more evenly across the bearing surfaces and connection points, reducing stress concentrations while maintaining power transmission efficiency.
Solution Approach 2:
The non-parallel axis arrangement changes the geometric parameters to optimize the balance between force transmission and stress distribution. By carefully positioning the axes of rotation relative to the connecting portions, the mechanism achieves efficient force transmission through the aerodynamic loads while minimizing stress concentrations at the connection points between the drive link, drive arm, and control surface mounting assembly.
Data Source
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AI summary
An aircraft control surface operating device is provided for operating a control surface on an aircraft body portion to move between a retracted position and an extended position. The aircraft control surface operating device includes a control surface mounting assembly which movably secures the control surface to the aircraft body portion, a drive arm rotatable about a drive axis relative to the aircraft body portion, an actuator for rotating the drive, and a drive link connecting the drive arm to the control surface mounting assembly. The drive link has a control end connected to the control surface mounting assembly and a driven end connected to the drive arm via a drive bearing joint. The drive link connects the drive arm and the control surface mounting assembly such that rotation of the drive arm is causes extending or retracting movement of the control surface.