Split Double Helical Planetary Gear Assembly for Easier Meshing
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Solution Overview
Problem
The assembly of single-piece double helical gears in planetary gear systems is challenging due to the opposing helical teeth angles, making meshing difficult and impractical, which affects power transmission efficiency and noise reduction in aircraft gearboxes.
Innovation Solution
A planetary gear system is designed with a split double helical ring gear, a single-piece double helical planet pinion, and a split double helical sun gear, where the first and second helical teeth portions of each component mesh and interlock via mating structures and a sun gear coupler, allowing for easier assembly and operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If single-piece double helical gears are used in planetary gear systems, then power density and noise reduction are improved, but assembly difficulty increases due to opposing helical teeth angles
Solution Approach 1:
The ring gear is divided into two separate helical gear segments (first and second helical ring gears) that can be assembled independently. This segmentation allows each segment to be meshed with the planet pinion separately, avoiding the assembly difficulty caused by opposing helical teeth angles while maintaining the power density benefits of double helical configuration
Solution Approach 2:
Instead of attempting to mesh a single-piece double helical planet pinion with opposing teeth angles directly, the invention inverts the approach by using two separate helical ring gears with matching teeth angles that mesh with opposite sides of the planet pinion. This reversal of the meshing strategy simplifies assembly while achieving the same functional result
2Object-generated harmful factors
If single-piece double helical gears are used in planetary gear systems, then noise is reduced, but meshing becomes difficult and impractical
Solution Approach 1:
The ring gear is segmented into two separate helical gear portions that can be independently positioned and meshed with the planet pinion. This segmentation eliminates the meshing difficulty caused by opposing helical teeth angles while preserving the noise reduction benefits of the double helical configuration through proper alignment of both segments
3Loss of energy
If tight-tolerance double helical gears are assembled, then power transmission efficiency is improved, but assembly precision requirements increase
Solution Approach 1:
By dividing the ring gear into two separate helical segments, the invention reduces the cumulative tolerance stack-up that would occur in a single-piece double helical gear. Each segment can be manufactured and assembled with more relaxed individual tolerances while maintaining the overall tight-tolerance performance needed for efficient power transmission
Solution Approach 2:
The two helical ring gear segments are designed to be pre-aligned and positioned relative to each other before final assembly with the planet pinion. This preliminary positioning action ensures proper meshing geometry is established beforehand, reducing the precision requirements during the critical meshing operation
Data Source
AI summary
In one embodiment of the present disclosure, there is provided a planetary gear system. The planetary gear system includes a split double helical ring gear having a first ring gear with first helical ring teeth and a second ring gear with second helical ring teeth, a split double helical sun gear having a first sun gear with first helical sun teeth and a second sun gear with second helical sun teeth, a sun gear coupler coupling the first sun gear and the second sun gear; and a single-piece double helical planet pinion having a first helical planet teeth portion and a second helical planet teeth portion, where the first helical planet teeth mesh with the first helical sun teeth and the first helical ring teeth, and the second helical planet teeth mesh with the second helical sun teeth and the second helical ring teeth.