Nested Planetary Reducer Layout for High Reduction Ratios
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Solution Overview
Problem
Conventional planetary reducers require increased size to achieve higher reduction ratios, limiting their compactness and efficiency.
Innovation Solution
The design incorporates a sun gear rod, gear assembly, first and second external gears, and planetary gears to create multiple interconnected reduction mechanisms, allowing for enhanced reduction ratios while minimizing the overall size of the reducer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the gear ratio is changed to achieve a larger reduction ratio, then the reduction ratio is improved, but the size of the planetary reducer increases
Solution Approach 1:
The patent employs nested planetary gear mechanisms where multiple planetary gears are arranged concentrically around a common sun gear. The first planetary gear and second planetary gear are nested within the same housing space, with the second planetary gear positioned outside the first planetary gear but both rotating around the same sun gear axis. This nesting arrangement allows multiple reduction stages to occupy overlapping spatial volumes, achieving high reduction ratios without proportionally increasing the overall reducer size.
Solution Approach 2:
The patent utilizes the radial dimension by arranging planetary gears at different radial distances from the sun gear center. The first planetary gear has a smaller pitch circle diameter and the second planetary gear has a larger pitch circle diameter, both meshing with the same sun gear. This dimensional arrangement allows multiple gear stages to be stacked radially rather than sequentially along a single axis, effectively using three-dimensional space to achieve compact high-ratio reduction.
2Productivity
If multiple planetary gears are added to increase reduction ratio, then the reduction ratio is improved, but the device complexity increases
Solution Approach 1:
The sun gear serves multiple functions simultaneously: it acts as the central gear for both the first planetary gear and the second planetary gear, providing the reference axis and meshing surface for both planetary stages. The common housing structure provides support and alignment for multiple planetary gears while maintaining a unified assembly architecture. This multi-functionality reduces the need for separate drive mechanisms for each planetary stage, thereby limiting complexity growth despite multiple reduction stages.
Data Source
AI summary
A planetary reducer contains: a sun gear rod, a gear assembly, a first external gear, and a second external gear. The sun gear rod includes an extension and a toothed section. The gear assembly includes a post, a first planetary gear, and a second planetary gear. Some of multiple teeth of the first planetary gear and some of multiple teeth of the second planetary gear expose outside the post. A number of the multiple teeth of the first planetary gear is different from a number of the multiple teeth of the second planetary gear. The first external gear includes a first surrounding portion and a first toothed portion which meshes with the first planetary gear. The second external gear includes a second surrounding portion and a second toothed portion which meshes with the second planetary gear.