Rotor Transmission Joint With Decoupled Torque and Force Paths
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Solution Overview
Problem
Current transmission joints for tilt-rotor aircrafts with elastomeric bearings face issues of reduced fatigue life, increased cost and weight, and complex maintenance due to overheating and the need for frequent inspection, which complicates the transition between 'airplane' and 'helicopter' configurations.
Innovation Solution
A transmission joint utilizing a constant velocity joint design with rollers and dampening elements made of alternating layers of elastomeric materials and steel, allowing for independent transmission of torque and aerodynamic forces while enabling oscillation of the hub relative to the control shaft, reducing the reliance on elastomeric bearings and simplifying maintenance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If elastomeric bearings are used to transmit torque and aerodynamic forces, then the transmission joint can handle both forces, but the fatigue life is reduced and the cost and weight increase
Solution Approach 1:
The invention divides the transmission joint into two separate functional paths: one for torque transmission (via the constant velocity joint mechanism) and another for aerodynamic force transmission (via the spherical bearing). This segmentation allows each component to be optimized for its specific function, reducing the overall stress and fatigue on any single element while maintaining the ability to handle both torque and aerodynamic forces simultaneously.
2Adaptability or versatility
If elastomeric bearings are used to transmit torque and aerodynamic forces, then the transmission joint can handle both forces, but the weight and cost increase
Solution Approach 1:
The invention divides the transmission joint into two separate functional paths: one for torque transmission (via the constant velocity joint mechanism) and another for aerodynamic force transmission (via the spherical bearing). This segmentation allows each component to be optimized for its specific function, reducing the overall stress and fatigue on any single element while maintaining the ability to handle both torque and aerodynamic forces simultaneously.
3Adaptability or versatility
If elastomeric bearings are used, then torque and force transmission is possible, but maintenance complexity increases due to overheating and frequent inspection needs
Solution Approach 1:
The invention divides the transmission joint into two separate functional paths: one for torque transmission (via the constant velocity joint mechanism) and another for aerodynamic force transmission (via the spherical bearing). This segmentation allows each component to be optimized for its specific function, reducing the overall stress and fatigue on any single element while maintaining the ability to handle both torque and aerodynamic forces simultaneously.
Solution Approach 2:
The spherical bearing acts as an intermediary element that specifically handles aerodynamic forces, while the constant velocity joint mechanism handles torque transmission. This intermediary arrangement allows each component to operate within its optimal performance range, reducing overheating issues and maintenance complexity associated with using a single elastomeric bearing for both functions.
4Difficulty of detecting and measuring
If a long probe is used to visually inspect components, then inspection can be performed, but the procedure becomes more cumbersome
Solution Approach 1:
The spherical bearing acts as an intermediary element that specifically handles aerodynamic forces, while the constant velocity joint mechanism handles torque transmission. This intermediary arrangement allows each component to operate within its optimal performance range, reducing overheating issues and maintenance complexity associated with using a single elastomeric bearing for both functions.
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 enhances the fatigue life, reduces weight and cost, and simplifies maintenance by decoupling the torque and force transmission paths, providing a more balanced and efficient operation during configuration transitions.
Implementation Method 1
A transmission joint utilizing a constant velocity joint design with rollers and dampening elements
Implementation Method 2
dampening elements made of alternating layers of elastomeric materials and steel
Implementation Method 3
dampening elements made of alternating layers of elastomeric materials and steel
Implementation Method 4
constant velocity joint design with rollers
Implementation Method 5
rollers and dampening elements
Data Source
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AI summary
An articulated transmission joint (20; 20'; 20'') for connecting a drive shaft (10) to a hub (15) of a rotor (8, 8', 8"), comprising: a first element (45, 45', 45") rotatable about a first axis (C); a second element (50, 51, 52; 50", 51'', 52'') rotatable about a second axis (D); and connecting means (60, 60', 60") to allow transmitting the motion between the first and the second element (45, 45', 45"; 50, 51, 52; 50", 51", 52") of a torque having a main component along the first axis (C) and a torque having a main component along the second axis (D); the connecting means (60, 60', 60") comprise, a roller (54) articulated on the first element (45, 45', 45''); and a chamber (53) defined at least partially by the second element (50, 51, 52; 50", 51", 52") and housing at least partially the roller (54); the chamber (53) is delimited towards the roller (54) by a first surface (59) that contacts the roller (54) circumferentially to the first axis (C), after the rotation of the first element (45) about the first axis (C); the first and second element (45, 45', 45"; 50, 51, 52; 50", 51", 52") are coupled so as to allow a tilt of an angle (α) between the first and second axis (C, D).