Aircraft Rotor Constraint Assembly Sliding Mechanism
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Solution Overview
Problem
Existing helicopter rotor assemblies are complex, heavy, expensive, and require constant lubrication and inspection due to alternating loads, leading to slack in connecting rods and increased maintenance needs, necessitating redundant systems to meet design redundancy requirements.
Innovation Solution
A rotor assembly with a simplified constraint assembly comprising a retaining arm and antirotation bracket, eliminating the need for hinges and reducing the number of components, allowing for a sliding connection that maintains precision and minimizes slack, thereby reducing weight and maintenance needs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a compass-type connecting device with hinged parts is used, then rotation prevention is achieved, but device complexity and weight increase
Solution Approach 1:
The connecting device is divided into separate functional elements: a retaining arm attached to the movable member and an antirotation bracket attached to the supporting member. This segmentation allows each component to be simple in structure while collectively achieving the rotation prevention function, eliminating the need for complex hinged mechanisms.
Solution Approach 2:
The invention extracts and eliminates the hinged parts from the connecting device structure. By using a direct sliding connection between the retaining arm and antirotation bracket without hinges, the design removes unnecessary mechanical complexity while maintaining the essential antirotation function through the sliding engagement mechanism.
2Reliability
If hinged connecting rods are used, then rotation constraint is provided, but maintenance requirements increase due to slack from alternating loads
Solution Approach 1:
The sliding connection between the retaining arm and antirotation bracket is designed to automatically maintain its functional relationship without requiring external lubrication or adjustment. The geometry of the sliding surfaces ensures continuous contact and constraint, allowing the device to maintain its antirotation function self-servingly over time without maintenance intervention.
3Reliability
If redundant connecting devices are implemented, then design redundancy requirements are met, but weight and cost increase
Solution Approach 1:
The invention changes the fundamental parameters of the connecting device by transitioning from hinged mechanical linkages to a direct sliding connection. This parameter change in the connection mechanism allows the device to achieve both redundancy and lightness, as the simplified structure requires fewer materials and components while maintaining the necessary safety margins through the robust sliding engagement.
Data Source
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AI summary
A constraint assembly (40) for an aircraft (1), having a first member (8); a second member (20) mounted to translate along and rotate about its own axis (A); and connecting means (39) for connecting the first and second member (8, 20), / to prevent rotation of the second member (20) about the axis (A) with respect to the first member (8); the connecting means (39) having a retaining arm (41), which projects outwards from one (20) of the first and second member (8, 20), and extends at a distance of other than zero from the axis (A); and an antirotation bracket (42), which projects from the other (8) of the first and second member (8, 20), extends at a distance of other than zero from the axis (A), and defines a through opening (43) engaged in sliding manner by the retaining arm (41).