Rotary Reduction Actuator Overlap Structure for Stable Power Transfer
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Solution Overview
Problem
Conventional rotary reduction actuators experience gear shaking during power transmission due to the center line of the tooth-contact section being deviated from the meshing section, leading to unstable power delivery and increased axial package dimension.
Innovation Solution
A rotary reduction actuator with an overlapping power transmission structure, where the center line of the tooth-contact section between the input and output-shaft gears is positioned within the meshing section between the input and ring gears, utilizing an eccentrically disposed input gear and a wobbling-motion inducing part with paired protrusions and receiving grooves to reduce gear shaking and minimize axial package.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of stationary object
If the center line of the tooth-contact section is deviated from the meshing section, then the axial package dimension is reduced, but gear shaking occurs during power transmission
Solution Approach 1:
The patent merges the tooth-contact section and meshing section by positioning their center lines to overlap with each other. This alignment ensures that the input gear's tooth-contact with the output-shaft gear occurs within the same axial region where the input gear meshes with the ring gear, eliminating gear shaking while maintaining compact axial dimensions.
Solution Approach 2:
The patent employs eccentric positioning of the input gear relative to the drive shaft, creating a wobbling motion that transfers power through both the tooth-contact section and meshing section simultaneously. This dimensional arrangement allows the center lines of both sections to overlap in the axial direction, resolving the contradiction between compact size and transmission stability.
2Stability of the object's composition
If the center line of the tooth-contact section is positioned within the meshing section, then gear shaking is reduced and power transmission is stabilized, but the axial package dimension increases
Solution Approach 1:
The patent nests the tooth-contact section within the meshing section by positioning the former inside the axial boundaries of the latter. The output-shaft gear is arranged concentrically with the drive shaft, while the input gear is eccentrically positioned, allowing the tooth-contact section to be nested within the meshing section's axial space. This nesting achieves stable power transmission without significantly increasing the overall axial package dimension.
3Stability of the object's composition
If an eccentric input gear with wobbling motion is used, then the center lines of tooth-contact and meshing sections can overlap, but the device complexity increases
Solution Approach 1:
The input gear serves multiple functions simultaneously: it transmits power through tooth-contact with the output-shaft gear, meshes with the ring gear for speed reduction, and generates wobbling motion through its eccentric positioning. This multi-functionality eliminates the need for separate components to achieve each function, reducing overall device complexity while maintaining stable power transmission.
Data Source
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AI summary
The present invention relates to a rotary reduction actuator capable of performing more stable power transmission by reducing shaking of gears during a power transmission process, by configuring a center line of a tooth-contact section between an input gear and an output-shaft gear to be positioned within a meshing section between the input gear and a ring gear in a reduction gear unit for reducing and outputting rotation of a drive shaft. The rotary reduction actuator includes a drive shaft installed on an output side of an electric motor, and a reduction gear unit configured to reduce and output rotation of the drive shaft. The reduction gear unit includes an input gear disposed eccentrically with respect to the drive shaft, an output-shaft gear interlocked with the input gear via a wobbling-motion inducing part, and a ring gear internally fitted to the input gear via an eccentric tooth-meshing portion. The eccentric tooth-meshing portion includes external teeth formed on an outer circumferential surface of the input gear and internal teeth formed on an inner circumferential surface of the ring gear. The wobbling-motion inducing part includes paired protrusions provided on an inner circumferential surface of the input gear and paired receiving grooves provided on an outer circumferential surface of the output-shaft gear. A center line of a tooth-contact section between the paired protrusions of the input gear and the paired receiving grooves of the output-shaft gear is positioned within a meshing section between the external teeth of the input gear and the internal teeth of the ring gear.