Shaft Mounted Rotor Brake with Centrifugal Speed Control
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Solution Overview
Problem
Conventional rotor brake systems for helicopters are limited to deployment only on the ground when the rotor reaches 40% to 50% of its rated speed, and actuating the brake above this range can lead to component deformation and overheating due to excessive thermal loads, posing safety risks and increasing manufacturing costs.
Innovation Solution
A shaft-mounted rotor brake with a braking force absorption element and a rotor speed-controlled deactivation device, utilizing lamellas and stationary lamellas within the rotor gearbox housing lubricated by gearbox oil, which absorbs heat and filters wear particles, and includes a centrifugal slide mechanism to prevent unintended actuation above critical speeds.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the rotor brake is designed to be effective at 70% to 100% of the rated rotor speed, then the braking performance is improved, but the weight and manufacturing costs increase substantially
Solution Approach 1:
The brake system uses a centrifugal activation mechanism with centrifugal elements that automatically engage the brake based on rotor speed. At low speeds (below 40-50% of rated speed), the centrifugal elements remain retracted, keeping the brake disengaged. As speed increases, the centrifugal force activates the brake automatically, providing speed-dependent braking performance without requiring a heavy-duty brake design for high-speed operation.
2Reliability
If the rotor brake is actuated above 40% to 50% of the rated rotor speed, then the braking capability is enhanced, but component deformation and overheating occur due to excessive thermal loads
Solution Approach 1:
The centrifugal activation mechanism creates a speed-dependent braking system that automatically prevents brake engagement above 40-50% of rated rotor speed. The centrifugal elements remain engaged only within the safe speed range, automatically disengaging at higher speeds to prevent excessive thermal loading and component deformation.
Solution Approach 2:
The centrifugal activation mechanism provides automatic feedback control based on rotor speed. The system continuously monitors speed through the centrifugal force generated by rotating elements, and automatically adjusts brake engagement state accordingly - engaging only when speed is within the safe 40-50% range and disengaging when speed exceeds this threshold, thereby preventing thermal overload.
3Device complexity
If a conventional rotor brake system is used without speed control, then the device complexity is reduced, but unintended actuation and overheating risks increase
Solution Approach 1:
The brake system uses the rotor's own rotational energy to control its own activation. The centrifugal elements, driven by the rotor's rotation, automatically engage or disengage the brake based on speed conditions without requiring external sensors, control systems, or additional power sources. This self-regulating mechanism provides safety against unintended actuation while maintaining relatively simple device complexity.
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 allows for a durable, low-maintenance rotor brake system that reduces pilot workload and minimizes misuse, effectively preventing overheating and component failure by engaging the brake only within safe operational ranges.
Implementation Method 1
said lamellas and stationary lamellas are arranged inside of the rotor gear box housing with oil inside
Implementation Method 2
at least one rotor speed-controlled rotor brake deactivation device
Data Source
AI summary
A shaft mounted rotor brake (7) with at least one braking force absorption element non-rotatable connected to said shaft (1). A stationary brake actuator (8, 24) is mounted to a rotor gear box housing (4). Said stationary brake actuator (8, 24) actuates a braking force transmission element (17, 23) that is functionally coupled to the at least one braking force absorption element (2) so as to exert a braking effect. At least one rotor brake deactivation device (6, 9, 25) is provided. The at least one braking force absorption element comprises lamellas (2) interacting with stationary lamellas (3), said lamellas (2) and stationary lamellas (3) being arranged inside of the rotor gear box housing (4) with oil inside.