Rotor Blade Coupling Device with Elastomeric Damping
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Solution Overview
Problem
Existing rotor blade coupling devices for rotorcraft are complex, with high maintenance efforts due to hydraulic damping elements and additional joints, which can generate negative dynamic effects and are complicated to install and maintain.
Innovation Solution
A rotor blade coupling device featuring a divided ring arrangement with plate-shaped transfer elements and damping devices, providing a simplified design with improved damping of lead-lag motions and reduced flapping motion effects, using elastomeric spherical bearing elements and plate dampers for efficient energy absorption and distribution of forces.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If hydraulic damping elements are used to adjust angular adjustment resistance, then damping of lead-lag motions is improved, but device complexity and maintenance effort increase
Solution Approach 1:
The patent replaces hydraulic damping elements with a purely mechanical damping device comprising a elastomeric element and a lever arm mechanism. The elastomeric element provides damping through its material properties while the lever arm mechanism provides the mechanical advantage needed for effective lead-lag motion damping, eliminating complex hydraulic systems entirely.
Solution Approach 2:
The patent extracts and eliminates the hydraulic damping elements from the rotor blade coupling device, retaining only the essential mechanical components needed for damping functionality. This simplification removes the complexity of hydraulic systems while preserving the core damping capability through the elastomeric element and lever arm mechanism.
2Reliability
If additional joints and connecting brackets are added between damping elements and rotor blade mountings, then damping functionality is improved, but ease of manufacture and maintenance deteriorate
Solution Approach 1:
The patent merges the damping element, lever arm, and connecting functionality into an integrated assembly that attaches directly to the rotor blade mounting. This consolidation eliminates the need for separate connecting brackets and multiple joints, simplifying both manufacturing and maintenance while preserving full damping functionality.
Solution Approach 2:
The lever arm mechanism serves multiple functions simultaneously: it provides mechanical advantage for damping, connects the elastomeric element to the rotor blade mounting, and accommodates the necessary motion geometry. This multi-functionality reduces the number of separate components needed.
3Reliability
If two joints spaced apart from the blade pitch axis are used, then lead-lag motion damping is achieved, but negative dynamic effects are generated
Solution Approach 1:
The patent positions the lever arm mechanism and elastomeric element at a specific location optimized for damping functionality, rather than using two separate joints spaced apart from the blade pitch axis. This localized arrangement achieves lead-lag motion damping while minimizing negative dynamic effects by concentrating the damping action at the most effective point.
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 achieves sound damping in the regressive mode, reduces the effect of collective and cyclic flapping motions, prolongs the service life of components, and simplifies installation and maintenance by minimizing additional joints and complex designs.
Implementation Method 1
elastomeric spherical bearing elements
Implementation Method 2
damping devices... using elastomeric spherical bearing elements and plate dampers for efficient energy absorption
Implementation Method 3
plate dampers for efficient energy absorption
Implementation Method 4
Such lead-lag motions are primarily caused by Coriolis forces and aerodynamic drag, wherein these lead-lag motions are also affected by centrifugal forces and inertial forces
Implementation Method 5
Such lead-lag motions are primarily caused by Coriolis forces and aerodynamic drag
Data Source
AI summary
A rotor blade coupling device for coupling to a rotor mast having a rotor head centerpiece. The coupling device has at least three rotor blade mountings mounted on the rotor head centerpiece and accommodating at least three rotor blades lying in a rotor plane, and at least one connecting element between adjacent rotor blade mountings. The rotor blade mountings can carry out pivoting motions about a pivoting axis extending vertical to the rotor plane. The at least one connecting element is a damping device, and the rotor blade coupling device has a plate-shaped transfer element, which respectively crosses a rotor blade mounting and is coupled to at least one damping device. The rotor blade coupling device has a simplified design and ensures improved damping of lead-lag motions.