Two-Sun Planetary Gearbox Layout for High Reduction in Tight Space
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Solution Overview
Problem
There is a need for a drive mechanism that achieves slow transmission ratios with a small space requirement without using worm or helical gears, while also providing a large gear ratio and power split in a compact installation space.
Innovation Solution
The design incorporates an annular drive with an epicyclic gear system, where the total number of planets is greater than the differential number of teeth, and the planets are offset relative to each other by a calculated angle to achieve a large gear ratio in a small space, with a torque motor and a hollow shaft, and the use of separate toothings for each sun gear to ensure proper meshing and alignment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a planetary gear system with two sun gears is used to achieve a large gear ratio, then the reduction ratio is improved, but the installation space requirement increases
Solution Approach 1:
The planetary carrier is segmented into multiple segments, each carrying a planet gear. This segmentation allows for optimized spatial arrangement of the planet gears around the sun gears, enabling compact configuration that achieves large reduction ratios without proportionally increasing installation space.
Solution Approach 2:
The planetary gear system with two sun gears and multiple planet gears creates a nested structure where planets orbit within the space defined by the sun gears. This nested arrangement maximizes the use of available space, allowing high reduction ratios to be achieved within a compact footprint by utilizing the radial and axial dimensions efficiently.
2Manufacturing precision
If multiple planets with separate toothings are used to ensure proper meshing, then the manufacturing precision is improved, but the device complexity increases
Solution Approach 1:
Each planet gear is equipped with separate toothings tailored to mesh with specific sun gears. This local customization of toothings ensures precise meshing alignment at each contact point, improving manufacturing precision. The separate toothings are designed with specific parameters (number of teeth, profile shift) optimized for their respective meshing relationships.
Solution Approach 2:
The patent utilizes parameter changes in the gear toothings, specifically varying the number of teeth and profile shift values for different planet gears. By adjusting these parameters, the meshing conditions are optimized for each planet-sun gear combination, ensuring proper alignment and contact while accommodating the geometric constraints of the two-sun-gear configuration.
3Productivity
If the total number of planets is greater than the difference number of teeth, then the gear ratio is improved, but the device complexity increases
Solution Approach 1:
The planetary carrier is designed as a dynamic structure that can accommodate multiple planet gears at different angular positions. This dynamic configuration allows the system to achieve high reduction ratios by distributing the load across multiple planets, with each planet contributing to the overall gear ratio multiplication effect.
Solution Approach 2:
Multiple planet gears serve universal functions in the system: each planet meshes with both sun gears, transmits power, and contributes to the reduction ratio. The redundant planet gears provide both functional benefits (higher reduction ratio, load distribution) and structural benefits (symmetry, balance), making the system more versatile and robust.
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
This configuration allows for a compact, high-gear ratio transmission with power split, enabling efficient slow-speed operation without the need for worm or helical gears, while maintaining a small installation space and ensuring precise alignment and meshing of the sun gears and planets.
Implementation Method 1
a planetary carrier supporting at least two planets, the individual planets of which roll on a first externally toothed sun gear
Implementation Method 2
a second externally toothed sun gear driven from it, wherein subtracting the number of teeth of the driving second sun gear from the number of teeth of the non-rotatably arranged first sun gear
Data Source
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AI summary
The invention relates to a drive with a speed-reducing planetary gearbox which is integrated into a housing, a drive motor which acts upon a peripheral web mounted on at least two planets, said individual planets rolling on one first sun wheel arranged in the housing and also on a driven second sun wheel. The subtraction of the number of teeth of the second sun wheel from the number of teeth of the first sun wheel gives an even-numbered number of differential teeth. The number of planets is equal to the number of differential teeth and all planets have the same number of teeth. Either at least one sun wheel has a profile shift or the individual planet has a separate toothing in addition to the profile shift(s) of the sun wheels for the respective engagement with the individual sun wheel. According to the invention, a drive which enables a speed-reducing gear ratio requiring a small amount of space without using a screw or helical gear transmission, is developed.