Sun-Gear-Free Robot Joint Transmission for High Torque Density
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing robot joint transmission structures, such as those using cycloidal pin gearboxes and harmonic gearboxes, face limitations in reduction ratio range, input speed, structural impact resistance, and processing complexity, which restrict their application and performance.
Innovation Solution
A thickened robot joint transmission structure employing dual thickened planetary gear rings driven by a planetary carrier, eliminating the need for a sun gear, allowing for two degrees of freedom and a large reduction ratio range, with a modular design and high power density, and utilizing a sun-gear-free structure with continuously changing gear thickness and helix angles for improved stability and accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If cycloidal pin gear reducer is used, then transmission precision is improved, but mechanism complexity and processing technology requirements increase extremely
Solution Approach 1:
The patent removes the sun gear from the traditional planetary gear system, extracting the problematic element that caused high complexity and processing requirements. This sun-gear-free design simplifies the mechanism while maintaining transmission precision through the planetary carrier-driven dual gear ring structure.
Solution Approach 2:
Instead of using the conventional sun gear as the driving element, the patent inverts the driving mechanism to use the planetary carrier as the driver. This inversion fundamentally changes the transmission path and simplifies the overall mechanism structure while achieving the desired precision.
2Volume of moving object
If harmonic gearbox is used, then structure compactness is improved, but structural impact resistance deteriorates due to elastic deformation requirements
Solution Approach 1:
The patent employs thickened planetary gears with continuously changing thickness in the tooth direction, along with continuously changed helix angles and pressure angles. These parameter variations strengthen the gear structure to resist impact while maintaining compact dimensions, eliminating the need for elastic deformation.
3Power
If dual thickened planetary gear rings are used, then power density and rigidity are improved, but device complexity increases
Solution Approach 1:
The planetary carrier serves multiple functions: it acts as the driving element, supports the planetary pins, and drives the dual thickened planetary gears. This multi-functionality reduces the need for separate components, thereby increasing power density without proportionally increasing complexity.
Solution Approach 2:
The patent merges the functions of the sun gear and planetary carrier into a single planetary carrier-driven system. By combining these elements and eliminating the sun gear, the structure achieves higher power density while the modular design keeps complexity manageable.
4Measurement precision
If thickened gears with continuously changing parameters are used, then motion accuracy is improved, but manufacturing difficulty increases
Solution Approach 1:
The patent uses gears with dynamically varying parameters - continuously changing thickness, helix angles, and pressure angles along the tooth direction. These dynamic parameter changes optimize motion accuracy while modern manufacturing techniques make production feasible.
Data Source
AI summary
A thickened robot joint transmission structure comprises a shell, dual gear rings and a planet carrier, wherein the planet carrier is fixed to the shell through a crossed roller bearing. Planet gears are dual thickened planet gears free of a sun gear. The input ends are a pair of gears or spiral bevel gears with a variable velocity ratio and are fixed to the shell through deep groove ball bearings. The dual thickened planet gears serve as a hollow for a cable, a related shaft or a line object to pass through after the sun gear is removed.