Aircraft Trigger Brake With Roller Jamming Mechanism
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Solution Overview
Problem
Current braking devices in aircraft actuator systems experience undesirable drag due to multiple static and dynamic friction plates, which increase the burden on the power drive unit and transmission system, especially at low operational temperatures.
Innovation Solution
A selectively operable trigger brake with a preloaded torsion spring and a roller jamming mechanism that allows limited rotational movement between the trigger brake and input shaft, utilizing a solenoid actuator to engage static and rotary braking elements and activate the roller jamming mechanism upon exceeding a predetermined rotational threshold.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If multiple static and dynamic friction plates are used in the brake, then the braking effectiveness is improved, but the drag on the actuator system increases
Solution Approach 1:
The brake employs a dynamic plate that rotates with the input shaft and a static plate, where the relative motion between them creates the braking effect only when needed. The dynamic configuration allows the brake to engage selectively without continuous drag, resolving the contradiction between braking effectiveness and energy loss.
Solution Approach 2:
The brake operates periodically rather than continuously, engaging only when braking is required and disengaging during normal operation. This periodic action eliminates continuous drag while maintaining effective braking capability when activated, addressing the contradiction between reliable braking and energy efficiency.
2Reliability
If the brake is fully effective as a braking mechanism, then the braking performance is improved, but the drag particularly at low operational temperatures increases
Solution Approach 1:
The brake utilizes changes in operational parameters such as temperature and rotational speed to modulate its effectiveness. At low temperatures, the brake maintains full braking capability when engaged while minimizing drag during non-braking conditions, adapting to environmental conditions to resolve the contradiction between performance and energy loss.
3Reliability
If the brake provides continuous drag on the actuator system, then the braking readiness is improved, but the burden on the power drive unit and transmission system increases
Solution Approach 1:
The brake is pre-positioned and ready for immediate engagement without requiring continuous application of braking force. The mechanical configuration allows the brake to be primed and responsive while minimizing the burden on the power drive unit during normal operation, resolving the contradiction between braking readiness and power consumption.
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 solution minimizes drag by using a compact design that reduces the power absorbed by the brake unit, allowing for a less powerful and lighter power drive unit, while ensuring rapid activation to stop actuator systems in case of faults, thus maintaining symmetric deployment of aircraft components.
Implementation Method 1
a preloaded torsion spring rotationally coupled to the input shaft but permitting a limited rotational movement between the trigger brake and the input shaft
Implementation Method 2
a roller jamming mechanism operable upon the relative rotation between the trigger brake and the input shaft exceeding a predetermined amount to stop rotation of the input shaft
Data Source
AI summary
A brake device for braking rotation of an input shaft, comprises a selectively operable trigger brake comprising a preloaded torsion spring rotationally coupled to the input shaft but permitting a limited rotational movement between the trigger brake and the input shaft; and a roller jamming mechanism operable upon the relative rotation between the trigger brake and the input shaft exceeding a predetermined amount to stop rotation of the input shaft upon operation of the trigger brake.