Nested Planetary Gear Train for High-Torque Compact Wind Gearboxes
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Solution Overview
Problem
Conventional wind turbine generating systems face challenges in achieving high torque load capacity while maintaining a small size and large transmission speed ratio, due to the limitations of simple planetary gear trains.
Innovation Solution
The gear box incorporates a first planetary gear train with an idle planetary gear and a pinion gear that share torque, allowing the pinion gear to float radially and reducing its torque load, while also utilizing staggered bull gears for increased transmission speed ratio.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the number of planetary gear is increased to improve torque load capacity, then the torque load capacity is improved, but the volume of the gear box increases
Solution Approach 1:
The patent implements a nested planetary gear structure where a second planetary gear is positioned inside the first planetary gear. The second planetary gear's sun gear is surrounded by the first planetary gear's planetary gears, creating a compact nested arrangement. This allows multiple planetary gears to occupy overlapping spatial regions, significantly increasing torque load capacity without proportionally increasing the overall gear box volume.
Solution Approach 2:
The patent transitions from a two-dimensional planar arrangement of planetary gears to a three-dimensional nested configuration. By stacking planetary gears in multiple layers along the axial direction and utilizing radial space more efficiently, the design accommodates more planetary gears within the same external dimensions, resolving the contradiction between torque capacity and volume.
2Volume of stationary object
If the size of gears is reduced to arrange more planetary gears in the same volume, then the volume requirement is met, but the transmission speed ratio decreases
Solution Approach 1:
The nested configuration allows the patent to maintain larger individual gear sizes while still fitting multiple planetary gears within the same volume. The sun gear and planetary gears are arranged in concentric nested layers, maximizing the use of radial and axial space. This enables the maintenance of large transmission speed ratios through larger gear diameter ratios while accommodating multiple planetary gears for high torque capacity within compact external dimensions.
3Device complexity
If a simple planetary gear train is used to maintain device simplicity, then the device complexity is low, but the torque load capacity is limited
Solution Approach 1:
The patent merges two planetary gear systems into a single integrated nested structure. The first and second planetary gears share common components such as the sun gear and gear ring, while their planetary gears are arranged in nested layers. This combined structure achieves high torque load capacity through the cumulative effect of multiple planetary gears while maintaining a unified, relatively simple overall architecture compared to having separate gear trains.
Solution Approach 2:
The nested planetary gear structure serves multiple functions simultaneously: it provides high torque load capacity through multiple planetary gears, achieves large transmission speed ratio through optimized gear ratios, and maintains compact volume through efficient space utilization. The sun gear and gear ring serve as shared components for both planetary gear stages, reducing the total number of parts and simplifying the overall structure.
Data Source
AI summary
A gear speed change device. The gear speed change device comprises a first planetary gear train (100). The first planetary gear train (100) comprises a first ring gear (101), a first planetary carrier (102), first planetary gears (103), a solar idle gear (104), and a planetary idle gear (105). The planetary idle gear (105) and the first planetary gears (103) are all mounted on the first planetary carrier (102); each first planetary gear (103) comprises a pinion (103a) and a large gear (103b) coaxially connected to the pinion (103a); the planetary idle gear (105) and the pinion (103a) are both engaged with the inside of the first ring gear (101) and are both engaged with the outside of the solar idle gear (104); the pinion (103a) can float along the radial direction thereof relative to the first planetary carrier (102), and the maximum radial floating amount of the pinion (103a) is greater than the maximum radial floating amount of the planetary idle gear (105); and the large gears (103b) of at least two first planetary gears (103) are arranged in a staggered manner in the axial direction, and projections thereof on a plane perpendicular to the axial direction overlap with each other. The gear speed change device has a relatively high torque load density, and can give consideration to a small volume, a large transmission speed ratio and a high torque load capability.