Counterbalanced Landing Gear Actuator for Fast Retraction
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Solution Overview
Problem
Aircraft landing gear actuation systems face high power and weight challenges due to high actuator loads and short retraction time requirements, necessitating a reduction in actuator loads, size, and weight, particularly with the need for electrified actuation.
Innovation Solution
An aircraft landing gear actuation system utilizing a hydraulic actuator with a pressurized fluid source that exerts a force on an actuator piston or rod to retract the landing gear, combining with a separate hydraulic fluid for efficient retraction and deployment, and incorporating a pressurized fluid counterbalance to reduce actuator size and energy consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If high power actuators are used to meet short retraction time requirements, then landing gear retraction speed is improved, but actuator weight and system weight increase
Solution Approach 1:
The patent uses a counterbalance chamber filled with pressurized fluid that exerts an upward force on the actuator piston, counteracting the weight of the landing gear. This reduces the net force required from the actuator, thereby reducing actuator weight and power requirements while maintaining retraction speed
Solution Approach 2:
The patent employs a hydraulic system where pressurized fluid is directed to both the actuator chamber for motion control and the counterbalance chamber for weight compensation. This dual-use hydraulic approach efficiently reduces actuator load without compromising retraction performance
2Speed
If high power actuators are used to meet short retraction time requirements, then landing gear retraction speed is improved, but energy consumption increases
Solution Approach 1:
The counterbalance chamber reduces the effective load on the actuator by providing an upward force that counteracts landing gear weight. This reduces the energy required from the actuator while maintaining the ability to achieve short retraction times when needed
Solution Approach 2:
The system uses periodic or intermittent application of pressurized fluid to the actuator, rather than continuous high-power operation. The counterbalance provides continuous support, allowing the actuator to operate in shorter, more energy-efficient bursts to achieve retraction
3Reliability
If larger actuators are used to handle high actuator loads, then landing gear retraction reliability is improved, but actuator size and weight increase
Solution Approach 1:
The counterbalance chamber provides continuous upward force to support the landing gear weight, reducing the peak and sustained loads on the actuator. This allows for a smaller actuator volume while maintaining reliability through the combined action of the actuator and counterbalance system
Solution Approach 2:
The system divides the load support function between two components: the actuator provides controlled motion and force, while the counterbalance chamber provides continuous weight support. This segmentation allows each component to be optimized for its specific function, resulting in a smaller overall system
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 system effectively reduces the size and energy requirements of the actuator, enabling efficient retraction and deployment of aircraft landing gear while providing a damping function for controlled movement and ensuring the landing gear can be locked in the deployed position, even in failure situations.
Implementation Method 1
pressurized fluid from the pressurized fluid source exerts a fluid pressure on the actuator piston
Implementation Method 2
pressurized fluid from the pressurized fluid source exerts a force on the actuator that biases the actuator piston and the actuator rod in a landing gear retraction direction
Implementation Method 3
The second retraction force may be used to help dampen movement of the aircraft landing gear from the retracted position to the deployed position
Data Source
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AI summary
An aircraft landing gear actuation system which uses two separate actuation forces to retract aircraft landing gear is disclosed. One of the actuation forces may be provided by an actuator, such as a hydraulic actuator. Another of these actuation forces may be provided by a pressurized fluid that is directed into the actuator through a conduit (232) that extends into a hollow interior of an actuator rod (206, 206') of the actuator. The pressurized fluid may be provided from a pressurized fluid source (230, 230') that contains a fixed volume of pressurized fluid. This pressurized fluid may exert a force on an actuator piston of the actuator or the actuator rod (206, 206'). The pressurized fluid may also be used to dampen the deployment of the landing gear.