Eccentric Transmission Mechanism Using External-Teeth Planetary Gearing
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Solution Overview
Problem
Conventional internal engagement transmission mechanisms face difficulties in machining due to the arrangement of internal teeth in the eccentric shaft, especially in small-sized components, which complicates the processing and increases manufacturing costs.
Innovation Solution
The transmission mechanism employs an outer wheel, inner wheel, eccentric shaft, first flange, rotating shaft, and planetary gearing devices with external teeth, allowing for power transmission between the rotating shaft and eccentric shaft through planetary gearing, reducing the need for internal teeth and simplifying machining.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If internal teeth are arranged in the eccentric shaft for direct engagement, then the structure is simple, but the machining difficulty increases significantly
Solution Approach 1:
The patent inverts the conventional approach by arranging external teeth on the rotating shaft instead of internal teeth in the eccentric shaft. This inversion allows the teeth to be machined from the outside where access is easier, while maintaining the engagement function. The planetary gearing device mediates the power transmission between the externally toothed rotating shaft and the eccentric shaft, resolving the machining difficulty while preserving structural simplicity.
Solution Approach 2:
The planetary gearing device serves as an intermediary between the rotating shaft and the eccentric shaft. It contains both a first planetary gear engaging with the rotating shaft's external teeth and a second planetary gear engaging with the eccentric shaft's external teeth. This intermediary mechanism enables power transmission without requiring difficult-to-machine internal teeth in the eccentric shaft.
2Volume of moving object
If the transmission mechanism is reduced to a small size, then the compactness improves, but the machining of internal teeth becomes even more difficult
Solution Approach 1:
By inverting the tooth arrangement to external teeth on the rotating shaft and planetary gears, the patent enables small-sized construction while maintaining machinability. External teeth can be precisely machined even on small components using standard gear cutting methods, whereas internal teeth in small hollow cavities become increasingly difficult to process as size decreases.
Solution Approach 2:
The transmission mechanism is segmented into multiple components: the rotating shaft with external teeth, the planetary gearing device with two sets of planetary gears, and the eccentric shaft with external teeth. This segmentation allows each component to be machined separately with appropriate tool access, avoiding the need to machine internal teeth in a confined small-space hollow cavity.
3Ease of manufacture
If external teeth are used on the rotating shaft and planetary gearing device, then the machining ease improves, but the device complexity increases
Solution Approach 1:
The planetary gearing device performs multiple functions: it transmits power from the rotating shaft to the eccentric shaft, provides speed reduction or multiplication, and enables the use of externally machined teeth throughout the transmission path. By consolidating these functions into a single compact planetary gear assembly, the patent achieves multi-functionality that justifies the moderate increase in structural complexity.
Solution Approach 2:
The patent merges the functions of multiple gear stages into a single planetary gearing device that simultaneously engages with both the rotating shaft and the eccentric shaft. This combining of functions into one integrated component achieves power transmission with external teeth while minimizing the overall structural complexity compared to using separate external gear trains.
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 enables efficient power transmission with a larger range of speed ratios while reducing manufacturing costs and time, as it utilizes easily machinable external teeth, and maintains dynamic balance during high-speed eccentric rotation.
Implementation Method 1
The at least one planetary gearing device is supported by the first flange. The periphery of each of the at least one planetary gearing device is provided with a first row of planetary teeth and a second row of planetary teeth. The first row of planetary teeth engage with the rotating shaft external teeth, and the second row of planetary teeth engage with the eccentric shaft external teeth.
Data Source
AI summary
Disclosed in the present invention is a transmission mechanism, comprising an outer wheel, an inner wheel, an eccentric shaft, a first flange body, a rotating shaft and a planetary gear device. The inner wheel is provided in the outer wheel and is engaged with the outer wheel. The eccentric shaft can rotate around a central axis; an eccentric portion, eccentric shaft outer teeth and a first support portion are provided on the periphery of the eccentric shaft; and the inner wheel is provided around the eccentric portion. The first flange body and the inner wheel are provided side by side, and the first flange body is provided around the first support portion. The rotating shaft has rotating shaft external teeth. The planetary gear device is supported by the first flange body, and a first row of planetary teeth engaged with the rotating shaft outer teeth and a second row of planetary teeth engaged with the eccentric shaft outer teeth are provided at the periphery of the planetary gear device. The transmission mechanism can provide a wide range of speed ratios and reduce production costs.