Turboprop Fan Blade Pitch Control via Eccentric Counterweights
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Solution Overview
Problem
Existing turboprop systems with adjustable fan blades face challenges in reliable and lightweight orientation control, often requiring complex mechanisms with intermediate parts prone to wear and maintenance issues.
Innovation Solution
A control device using a bevel gear system with a counterweight mechanism, where each blade is coupled to a rotary ring via a toothed wheel and counterweight, allowing for synchronized angular movement without intermediate guiding parts, ensuring easy maintenance and reduced mass.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a complex mechanism with intermediate guiding parts is used for blade orientation control, then the control precision can be improved, but the device complexity and mass increase, and reliability decreases due to wear-prone parts
Solution Approach 1:
The patent removes intermediate guiding parts from the control mechanism, extracting only the essential elements needed for blade orientation control. The direct coupling of the blade to the rotating ring through the simplified linkage eliminates unnecessary components that would increase complexity and maintenance requirements.
Solution Approach 2:
The control mechanism is segmented into discrete functional elements: the rotating ring, the linkage arms, and the blade mounting points. This segmentation allows for simpler individual components that are easier to manufacture and maintain, while collectively achieving the required control precision.
2Reliability
If intermediate guiding parts are used in the control mechanism, then the blade orientation control can be achieved, but the reliability decreases due to wear phenomena and maintenance requirements
Solution Approach 1:
The simplified control mechanism requires minimal intervention and maintenance. The direct linkage system without intermediate guiding parts reduces wear points, allowing the mechanism to operate reliably with less frequent maintenance and easier serviceability.
3Weight of moving object
If a simplified control mechanism without intermediate parts is used, then the device mass and complexity are reduced, but the reliability may worsen due to fewer redundancy options
Solution Approach 1:
The patent merges the functions of multiple separate components into a integrated linkage system that directly couples the blade to the rotating ring. This consolidation reduces the total mass while maintaining reliability through the robustness of the simplified direct connection, eliminating weak points that would exist in multi-component systems.
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 provides a reliable, lightweight, and easy-to-maintain orientation control system for turboprop fan blades, eliminating the need for complex intermediate parts and reducing wear, while ensuring efficient thrust management and safety through stable angular positioning.
Implementation Method 1
carrying a counterweight eccentric by relative to its axis of rotation
Implementation Method 2
a bevel gear formed of a first toothed wheel integral with the blade root support and centered on an axis radial to the rotary ring and a second toothed wheel integral with the rotary ring
Data Source
Figure 1~4B
Figure 2
Figure 3A~3B
AI summary
The invention relates to a device for controlling the orientation of fan blades of a turboprop engine comprising at least one set (24a, 24b) of adjustable-orientation fan blades rotatably secured to a rotary ring (28a, 28b) mechanically linked to a turbine rotor (22a, 22b). Each blade of the set is coupled to a blade shank support pivotably mounted to the rotary ring by means of a bevel gear formed by a first toothed wheel solidly connected to the blade shank support and a second toothed wheel (50) solidly connected to the rotary ring and bearing a counterweight (54) located eccentrically to the axis of rotation thereof. The invention also includes a cylinder (30a, 30b), rotatably connected to the turbine rotor and including a rod (32a, 32b) that is connected to each counterweight (54) by means of a linking arm, which cylinder can be used for the angular and synchronised movement of the set of counterweights around the axis of rotation of the respective toothed wheel thereof.