Aircraft Power Plant Connecting Rods for Misalignment Control
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Solution Overview
Problem
Rotorcraft power plants equipped with piston engines face challenges in maintaining proper alignment of power transmission components due to relative movements between the engine and power transmission box, leading to potential misalignment and deterioration, which is difficult to predict and size without complex tests.
Innovation Solution
The power plant incorporates two connecting rods articulated by ball joints to the engine and power transmission box, limiting relative movements to predictable rotations around a common geometric axis, allowing for refined dimensioning of the transmission shaft and reducing stress on elastic coupling means by biasing them in bending rather than shear or tension.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If a rigid connecting trumpet is used to limit misalignment, then alignment stability is improved, but device complexity increases and manufacturing precision requirements worsen
Solution Approach 1:
The power transmission chain is segmented into modular components (engine, transmission shaft, power transmission box, elastic coupling means) that can independently accommodate movements. This segmentation allows each component to be optimized separately while maintaining overall alignment stability without requiring a complex rigid connecting structure.
Solution Approach 2:
The patent changes the approach from rigid constraint to elastic deformation by introducing elastic coupling means. The coupling means changes its physical state from rigid to flexible, allowing it to absorb misalignments through elastic deformation rather than requiring precise rigid positioning.
2Reliability
If elastic coupling means are used to accommodate misalignment, then reliability is improved, but the coupling means is subjected to significant efforts and deteriorates faster
Solution Approach 1:
The elastic coupling means acts as a pre-designed cushioning element that absorbs misalignments before they can transmit damaging forces to the transmission shaft. By anticipating and absorbing the shocks and misalignments in advance, the system protects the more critical components from deterioration.
3Adaptability or versatility
If the transmission shaft is designed with sufficient flexibility to allow misalignment, then adaptability is improved, but manufacturing precision and structural integrity worsen
Solution Approach 1:
The elastic coupling means serves as an intermediary element between the transmission shaft and the power transmission components. It absorbs the misalignment adaptability requirements, allowing the transmission shaft to maintain its structural integrity and manufacturing precision while still accommodating movements through the coupling means.
4Loss of energy
If piston engine is used instead of turbine engine, then ecological and economic benefits are improved, but unpredictable movements increase causing more misalignment
Solution Approach 1:
The patent applies dynamic principles by introducing elastic coupling means that can adapt to the varying movements of the piston engine. The coupling means dynamically deforms to accommodate the unpredictable movements during start-up, acceleration, and operation, maintaining alignment stability despite the engine's variable motion characteristics.
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
This configuration reduces unpredictable movements, improves the service life of elastic coupling means, and allows for better evaluation and sizing of the power transmission chain, enhancing the power plant's reliability and durability, especially when used with piston engines driving rotorcraft rotors.
Implementation Method 1
Each flexible coupling means deforms in the event of axial or angular misalignment to allow this misalignment and limit the impact of the misalignment on the transmission shaft
Implementation Method 2
Each link rod is articulated by a ball joint to the power transmission box and the engine
Data Source
Figure 1~3
Figure 4~5
AI summary
The present invention relates to a drive unit (10) comprising a heat engine (15), a power transmission unit (20), and a power transmission chain (30). The drive unit (10) has two connecting rods (41, 42) extending respectively in a first direction (101) and a second direction (102) that are not parallel and intersect a common geometric axis (103) of rotation, each connecting rod (41, 42) being articulated by a ball joint (50) to the power transmission unit (20) and to the engine (15) to eliminate relative movement in said longitudinal direction (100) between the power transmission unit (20) and the engine (15) and to allow limited rotation of said power transmission unit (20) and said engine (15) with respect to said geometric axis (103).