Rotorcraft Rotor Flapping Abutment Mechanism
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Solution Overview
Problem
Existing rotorcraft rotor systems face challenges in effectively limiting the flapping movement of blades, particularly under external forces like wind, and in preventing detachment of spherical abutment components due to lack of centrifugal force, which can lead to mechanical imbalance and inefficiency.
Innovation Solution
A rotorcraft rotor with a stop mechanism featuring a laminated spherical abutment and a hook with a J-shaped groove, where a lever pivots under centrifugal force to engage or disengage the abutment end, limiting flapping movements by asymmetric support zones and using a return means to position the lever for engagement, thus preventing undue rotation and maintaining the abutment end in the groove.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If a stop mechanism is provided to limit flapping movement of blades, then blade stability is improved, but device complexity increases due to additional abutment members and tracks
Solution Approach 1:
The patent combines the lower abutment ring and upper abutment members into a unified stop mechanism system where the lower abutment ring serves as a common structure for all blades while upper abutment members are selectively positioned. This merging approach reduces the total number of independent components compared to having separate stop mechanisms for each blade, thereby improving blade stability while controlling device complexity.
Solution Approach 2:
The lower abutment ring serves multiple functions: it acts as a common stop structure for all blades, provides a reference structure for positioning upper abutment members, and contributes to overall rotor stability. This multi-functionality reduces the need for additional specialized components, resolving the contradiction between stability improvement and complexity increase.
2Stability of the object's composition
If upper abutment members are positioned to limit flapping movement, then blade control is improved, but ease of operation deteriorates due to risk of impeding upward mobility during rotation
Solution Approach 1:
The patent positions upper abutment members at specific locations and orientations tailored to each blade's requirements. Each upper abutment member is locally optimized to limit flapping movement in critical directions while maintaining upward mobility during rotation. This localized customization allows precise control where needed without unnecessarily restricting blade operation elsewhere.
Solution Approach 2:
The stop mechanism is designed to be dynamically adaptive: during rotation, centrifugal force and blade aerodynamics naturally overcome the abutment constraints, allowing free upward flapping motion. During stationary or low-speed conditions, the abutment members actively limit flapping movement. This dynamic behavior resolves the contradiction between control and ease of operation.
3Ease of manufacture
If spherical abutment components are used for blade articulation, then ease of manufacture is improved, but reliability deteriorates due to potential detachment in absence of centrifugal force
Solution Approach 1:
The patent incorporates preventive measures against spherical abutment detachment by designing the lower abutment ring and upper abutment members to work together as an interconnected system. The lower abutment ring provides a foundational structure that prevents spherical abutments from detaching during ground operations or low-speed conditions when centrifugal force is insufficient. This preliminary protective action maintains reliability while preserving the manufacturing advantages of spherical abutments.
4Manufacturing precision
If multiple abutment members are provided per blade, then flapping limitation precision is improved, but device complexity increases due to additional components
Solution Approach 1:
The patent divides the stop mechanism into two functional segments: a lower abutment ring that provides common support for all blades, and upper abutment members that provide blade-specific flapping limitation. This segmentation allows precise control of each blade's flapping motion while avoiding the need for multiple complex components per blade, as the lower ring handles common functions and upper members handle specific adjustments.
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 effectively limits flapping movements at low rotor speeds, prevents blade detachment, and maintains mechanical balance by ensuring the abutment end remains engaged, allowing free flapping at higher speeds without hindrance, thus enhancing rotor stability and operation efficiency.
Implementation Method 1
at least one lever (35) capable of blocking said abutment end (30) in flapping under the effect of a centrifugal force
Implementation Method 2
a return means (45) positioned on said lever (35) and tending to position this lever (35) in said engagement position
Data Source
Figure 1~2
Figure 3~5
Figure 6~7
AI summary
The present invention relates to a rotor (2) of a gyroplane (1) equipped with a plurality of lift assemblies (10), said rotor (2) having a flapping stop mechanism (20) per lift assembly (10). Each stop mechanism (20) comprises a projection (25) integral with a lift assembly (10) comprising a stop end (30) provided with an inner face (31) and an outer face (32), and at least one pivoting lever (35) extending longitudinally from a weight (40) to a hook (50). The hook (50) is provided with two elevation walls (53, 54) and a bottom wall (55) forming a periphery which delimits said groove (52), a first elevation wall (54) comprising an upper support zone (54') to block said internal face (31) and a second elevation wall (53) comprising a lower support zone (53') to block said external face (32).