Planetary Gear Reducer Flexible Cylindrical Support
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Solution Overview
Problem
In aircraft power transmission mechanisms, planetary gear reducers experience misalignment due to bending deformation, leading to edge contact and reduced lifespan, and existing solutions either increase weight or compromise rigidity.
Innovation Solution
A planetary gear reducer design featuring a cylindrical support with a V-shaped flexible structure and varying diameters to absorb deformation and maintain rigidity without increasing weight, incorporating a larger-diameter cylindrical portion with a smaller wall thickness and a flexible structure with a V-shaped cross-section to prevent misalignment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a structure supporting both ends of the rotating shaft is used to prevent misalignment, then misalignment is prevented, but the engine weight increases
Solution Approach 1:
The support structure is segmented into two distinct parts: a rigid support portion for the input shaft and a flexible support portion for the ring gear. This segmentation allows each part to perform its specialized function - the rigid portion provides stable support without deformation, while the flexible portion absorbs engine deformation, preventing misalignment without requiring a heavy dual-end support structure
Solution Approach 2:
Different parts of the support structure have different mechanical properties tailored to their specific functions. The rigid support portion has high stiffness to prevent input shaft deformation, while the flexible support portion has controlled compliance to absorb engine deformation. This local differentiation of structural properties allows the system to prevent misalignment without uniformly increasing the weight of the entire support structure
2Reliability
If flexible support structures are used for both sun gear and ring gear to absorb engine deformation, then misalignment is prevented, but the rigidity of the rotation system becomes insufficient causing excessive whirling
Solution Approach 1:
The support structure is divided into rigid and flexible portions, with only the flexible support portion providing compliance for alignment stability. The rigid support portion maintains high rotational rigidity to prevent whirling. This segmentation allows the system to simultaneously achieve both alignment stability and rotational rigidity without compromising either property
Solution Approach 2:
The rigid support portion is designed with high stiffness to provide rotational stability and prevent whirling, while the flexible support portion is designed with controlled compliance to absorb engine deformation and maintain alignment. This local differentiation ensures that rigidity is maintained where needed for rotation stability, while flexibility is provided where needed for deformation absorption
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 design effectively prevents misalignment and edge contact, enhancing the gear reducer's life performance while maintaining sufficient rigidity and reducing weight, thus improving the overall engine structure.
Implementation Method 1
a flexible structure provided at one part of the cylindrical support along a direction of a central axis of the input shaft between the first cylindrical portion and the second cylindrical portion, the flexible structure is curved radially inward and has a V-shaped longitudinal section
Data Source
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AI summary
A planetary gear reducer (1) includes: a sun gear (5) having external teeth and fixed concentrically to a power input shaft (3); a plurality of planet gears (7) having external teeth and mashing with the sun gear (5); a ring gear (9) having internal teeth and meshing with the planet gears (7); a planet carrier (11) configured to support a plurality of planet shafts (13), each of which is a rotational axis of a corresponding one of the planet gears (7), and to output revolution of the plurality of planet gears (7) as first power; and a cylindrical support (27) connected to the ring gear (9) such that the cylindrical support (27) is non-rotatable relative to the ring gear (9), the cylindrical support (27) being configured to output rotation of the ring gear (9) as second power. The cylindrical support (27) includes, at its one part along the direction of a central axis, a flexible structure (41) which is curved radially inward and has a V-shaped longitudinal section. This configuration makes it possible to both obtain rigidity and prevent misalignment while suppressing an increase in the weight of the gear reducer.