Split Cam Brake With Wedging Rollers for Back-Drive Prevention
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Solution Overview
Problem
Current rotary actuator braking systems for aircraft are too large for confined spaces and generate heat due to friction plates, leading to inefficiencies and potential damage, making them unsuitable for modern aircraft designs.
Innovation Solution
A split cam braking system with a driving cam and wedging cam, utilizing cylindrical rollers to prevent back-drive without friction plates, allowing for a compact, efficient, and easy-to-assemble solution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If friction plates are used in braking systems, then braking force is generated, but heat is generated causing wear and inefficiency
Solution Approach 1:
The patent replaces the traditional friction-based mechanical braking system with a cam-based mechanical system that uses geometric transformation instead of friction. The cam mechanism converts rotational motion into linear motion to apply braking force, eliminating the friction plates that generate harmful heat while maintaining effective braking capability.
2Force
If multiple friction plates are used in disc type or skewed roller type braking systems, then braking force is improved, but the system size becomes larger than desired
Solution Approach 1:
The braking system is segmented into distinct functional components: a driving cam, a follower cam, and a braking element. This segmentation allows each component to be optimized independently and packed efficiently in space. The cam mechanisms are designed with specific geometric profiles that enable compact arrangement while delivering the required braking force, reducing overall system volume compared to multi-plate friction systems.
Solution Approach 2:
The cam mechanisms are designed to nest within each other or arrange in a compact configuration where the driving cam and follower cam occupy overlapping or adjacent spaces. This nesting approach allows the braking system to achieve high braking force in a reduced volume by efficiently utilizing three-dimensional space rather than requiring linear stacking of multiple friction plates.
3Reliability
If traditional braking systems are used, then back-drive prevention is achieved, but the system is too large for confined aircraft spaces
Solution Approach 1:
The cam mechanisms are designed with dynamic geometric profiles that automatically adjust their mechanical advantage during operation. During normal rotation, the cams follow their designed profiles to transmit motion efficiently. When back-drive is attempted, the cam geometry transforms to create a mechanical lock or increased resistance, providing reliable back-drive prevention. This dynamic behavior allows the system to maintain compact dimensions while ensuring reliability under different operational conditions.
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 split cam design effectively prevents back-drive in rotary actuators, reducing heat generation and wear, while being compact enough to fit in smaller aircraft spaces and simplifying assembly.
Implementation Method 1
The plurality of cylindrical rollers is configured to wedge between a surface of the wedging cam and the housing when the torque is applied to the downstream side, thus preventing back-drive
Data Source
AI summary
A system and method for preventing back-drive in a braking system for a rotary actuator. The braking system comprises a housing and split cam design. A driving cam located within the housing is associated with an upstream side of the braking system. The driving cam is configured to rotate when a torque is applied to the upstream side. The braking system has a wedging cam and a plurality of cylindrical rollers. The wedging cam located within the housing and is associated with a downstream side of the braking system. The wedging cam is configured to react and prevent back-drive motion when torque is applied to the downstream side. The plurality of cylindrical rollers is positioned between the wedging cam and the housing. The plurality of cylindrical rollers is configured to wedge between a surface of the wedging cam and the housing when the torque is applied to the downstream side.