Actuator for Flight Control Surface Using Pin-and-Bush Transmission
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Solution Overview
Problem
Existing aircraft actuator systems that use electric motors with pivotable outlet shafts and screw-and-nut systems project from airfoil surfaces, causing aerodynamic disturbances due to their mechanical structure.
Innovation Solution
An actuator design featuring a motor-drive device with a pivotable outlet shaft that drives movement through a system of orthogonal axes, utilizing a pin and bush mechanism to transmit turning movement between mutually orthogonal axes, minimizing projections from airfoil surfaces and reducing aerodynamic interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a conventional actuator with electric motor and screw-and-nut system is used, then the actuator can drive flight control surfaces, but it projects from airfoil surfaces causing aerodynamic disturbances
Solution Approach 1:
The patent extracts the harmful projecting components (screw-and-nut system and associated mechanical linkages) from the actuator assembly and replaces them with a compact pin-and-bush mechanism. This removes the source of aerodynamic disturbances while preserving the essential function of transmitting rotational motion from the motor to the flight control surface.
Solution Approach 2:
The patent transitions from a linear/screw-based motion transmission approach to a rotational pin-and-bush mechanism that operates in a different dimensional space. The pin rotates within the bush, converting the motor's rotation into the required flight surface movement through a compact angular transmission rather than linear progression, thereby reducing the actuator's projection from the airfoil surface.
2Volume of moving object
If the outlet shaft is extended by a pin pivotally received in a bush to transmit movement between orthogonal axes, then the actuator becomes compact and reduces projections, but the transmission becomes non-homokinetic
Solution Approach 1:
The patent accepts and works with the non-homokinetic transmission characteristic rather than attempting to correct it. By changing the transmission parameters to accommodate the pin-and-bush geometry, the system achieves compactness and reduced aerodynamic interference. The control system can compensate for the non-uniform velocity ratio through electronic control, maintaining adaptability despite the geometric constraints of the compact mechanism.
Data Source
AI summary
An actuator for hinging a first element to a second element about a first pivot axis (A1), the actuator comprising a motor-drive device, a first mounting plate (4) connected to a body (2) of the motor-drive device, a second mounting plate (5) connected to the second element, the second mounting plate being mounted in the first mounting plate in order to pivot about the first axis, and a bush (6) mounted in the second mounting plate to pivot about a second axis (A2) perpendicular to the first axis. The motor-drive device has an outlet shaft (3) pivotable about a third axis (A3) perpendicular to the first axis and intersecting the first axis, and it is extended by a pin (7) that is pivotally received in the bush and that has a central axis (A4) intersecting the first axis and the third axis, and forming an acute angle with the third axis.An aircraft guidance assembly including such an actuator.