Complex Planetary Gear Layout for High Reduction in Compact Space
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing complex planetary gear units face challenges in achieving a high speed reducing ratio while maintaining a compact size, as increasing the speed reducing ratio often results in increased size in either the axial or radial direction, making them unsuitable for industrial machines and vehicles.
Innovation Solution
A complex planetary gear unit design where the first and second planetary gears are formed integrally around a common rotational axis, and the third and fourth planetary gears are formed integrally around another common rotational axis, with specific gear ratios between the gears to achieve a high speed reducing ratio comparable to that of a unit combining four sets of planetary gear units, while being downsized to a size comparable to three sets of units.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If the speed reducing ratio is increased by combining multiple planetary gear units or using larger gears, then the output torque is multiplied by a larger factor, but the size of the planetary gear unit increases in axial or radial direction
Solution Approach 1:
The patent combines multiple planetary gear sets (first and second planetary gear sets) into a single integrated unit where they share common components. Specifically, the second sun gear serves as the third planetary gear in the first planetary gear set, and the third sun gear serves as the second planetary gear in the second planetary gear set. This merging allows achieving a high speed reducing ratio comparable to four separate units while maintaining a compact size similar to three sets.
Solution Approach 2:
The patent implements multi-functionality by designing gears that serve multiple roles within different planetary gear sets. The second sun gear functions both as the second sun gear in the first planetary gear set and as the third planetary gear in the same set. Similarly, the third sun gear acts as both the third sun gear and the second planetary gear in the second planetary gear set. This universal design enables torque multiplication without proportional size increase.
2Productivity
If larger gears with larger number of teeth are arranged in the complex planetary gear mechanism, then the speed reducing ratio is increased, but the size of the planetary gear unit increases in radial direction
Solution Approach 1:
The patent employs a nested arrangement where planetary gears are positioned within the structure of sun gears of other planetary gear sets. The second planetary gear is nested within the third sun gear, and the third planetary gear is nested within the second sun gear. This nesting allows the gears to share space efficiently, achieving a high speed reducing ratio without increasing the radial footprint of the unit.
3Productivity
If a plurality of complex planetary gear mechanisms are arranged in line, then the speed reducing ratio is increased, but the size of the planetary gear unit increases in axial direction
Solution Approach 1:
Instead of arranging multiple planetary gear mechanisms in a linear axial sequence, the patent reorganizes them in a concentric radial arrangement around a common axis. The first and second planetary gear sets are positioned side-by-side in the radial direction, sharing common sun gears and planetary gears. This dimensional reorganization achieves high speed reduction without extending the axial length, making the unit suitable for compact installations.
Data Source
AI summary
A planetary gear unit includes a first gear, a second gear, and a third gear arranged coaxially while allowed to rotate relatively. A first planetary gear and a second planetary gear are integral, and a third planetary gear and a fourth planetary gear are integral. The planetary gears are rotatably supported by a carrier. The first planetary gear is meshed with the first gear, the second planetary gear is meshed with the second gear, the third planetary gear is meshed with the second gear, and the fourth planetary gear is meshed with the third gear. A gear ratio between the first planetary gear and the first gear is different from a gear ratio between the second planetary gear and the second gear, and a gear ratio between the third planetary gear and the second gear is different from a gear ratio between the fourth planetary gear and the third gear.