Two-Stage Differential Cycloidal Speed Reducer for High Rigidity
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Solution Overview
Problem
Conventional speed reducers, such as harmonic drives and RV speed reducers, lack rigidity and have large sizes and weights, which affect the inertia and load capacity of robots, particularly in applications requiring compact and high reduction ratios.
Innovation Solution
A two-stage differential cycloidal speed reducer design featuring a crank shaft input shaft with opposing first and second crank shaft portions, a first and second cycloidal gear, and annular gears with ring pins, providing a high reduction ratio through sliding contact and symmetrically arranged supporting crank shafts to connect and actuate the cycloidal gears.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If harmonic drive is used, then transmission ratio is large and operation is smooth, but rigidity is insufficient and motion accuracy deteriorates over time
Solution Approach 1:
The patent divides the speed reduction function into two independent stages: a harmonic drive stage providing high reduction ratio and smooth operation, and a cycloidal gear stage providing rigidity and precision. Each stage operates independently to compensate for the other's deficiencies, resolving the contradiction between transmission ratio and rigidity.
2Stability of the object's composition
If RV speed reducer is used, then rigidity is improved, but size and weight increase, affecting inertia
Solution Approach 1:
The patent merges two different gear mechanisms (harmonic drive and cycloidal gear) into a single integrated two-stage speed reducer. This combination achieves the rigidity of cycloidal gears while maintaining compact size through efficient space utilization, avoiding the excessive weight of conventional RV speed reducers.
3Weight of moving object
If compact speed reducer is employed, then inertia is reduced, but reduction ratio may be insufficient
Solution Approach 1:
The patent segments the speed reduction function into two stages with different characteristics: the first stage (harmonic drive) provides high reduction ratio in a compact form, while the second stage (cycloidal gear) provides additional reduction and rigidity. This segmentation achieves high overall reduction ratio without excessive size or weight.
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
The design enhances the rigidity and reduces inertia, achieving a compact and efficient speed reduction with improved motion accuracy and dynamic balance, suitable for robotic applications.
Implementation Method 1
a first annular gear provided on one end of the input shaft adjacent the first cycloidal gear and having a plurality of first ring pins provided around the outer circumference of the first cycloidal gear and being in sliding contact with the plurality of teeth of the first cycloidal gear
Data Source
AI summary
A two-stage differential cycloidal speed reducer with a high reduction ratio is provided, including: a plurality of supporting crank shafts; an input shaft including a first crank shaft portion and a second crank shaft portion; a first cycloidal gear provided on the first crank shaft portion; a second cycloidal gear provided on the second crank shaft portion and connected with the first cycloidal gear through the supporting crank shafts; a plurality of first ring pins provided around the outer circumference of the first cycloidal gear and in sliding contact with a plurality of teeth on the periphery of the first cycloidal gear; a first annular gear with the plurality of first ring pins; a plurality of second ring pins provided around the outer circumference of the second cycloidal gear and being in sliding contact with a plurality of teeth on the periphery of the second cycloidal gear; and a second annular gear with the plurality of second ring pins.