Industrial Robot Wrist Unit Eccentric Rocking Reduction Gear
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Solution Overview
Problem
Conventional wrist units of industrial robots with eccentric rocking-type reduction gears face challenges in size and complexity due to load concentration on crankshafts and bearings, requiring larger components and complicating assembly and disassembly processes.
Innovation Solution
A wrist unit design featuring a second wrist drive motor and an eccentric rocking-type reduction gear with a hollow forming part and through shaft, allowing for efficient power transmission and compact configuration by aligning the rotation center axial line with the second axial line, reducing the need for separate phase-matching parts and simplifying assembly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If the opposite side gear is arranged offset from the crankshaft in the radial direction to engage with the input gear, then the reduction gear can transmit drive power, but the center axial line of the opposite side gear cannot be arranged on the same axial line as the center axial line of the reduction gear, requiring separate phase-matching parts and complicating assembly
Solution Approach 1:
The patent applies asymmetry by positioning the opposite side gear's center axial line coaxially with the reduction gear's center axial line, while the crankshaft remains offset from this axial line. This asymmetric arrangement allows the opposite side gear to engage with the input gear on the crankshaft while maintaining coaxial alignment for simplified assembly and positioning.
2Productivity
If the crankshaft is positioned offset from the center axial line to provide eccentric motion, then the reduction gear can achieve deceleration and motion transformation, but the load concentrates at the crankshaft, requiring larger crankshaft and bearing sizes
Solution Approach 1:
The patent introduces a new spatial dimension by arranging multiple crankshafts around the through shaft in a circular pattern rather than using a single offset crankshaft. This distributes the load across multiple crankshafts and their supporting bearings, reducing the size requirements for each individual component while maintaining the eccentric rocking motion function.
3Device complexity
If a single crankshaft with input gear is used to transmit drive power, then the structure is simpler, but the load concentrates at that crankshaft and its bearings, making them larger in size
Solution Approach 1:
The patent segments the single crankshaft function into multiple crankshafts arranged around the through shaft. Each crankshaft has its own input gear that engages with the opposite side gear, distributing the mechanical load across multiple components. This segmentation reduces the size of individual crankshafts and bearings while maintaining the overall reduction gear functionality.
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 design enables efficient power transmission, reduces the size of the reduction gear, and simplifies assembly and disassembly by allowing the rotation center axes of the reduction gear to be aligned, resulting in a more compact and easier-to-maintain wrist unit.
Implementation Method 1
a gear member provided rotatably centered about the rotation center axial line, the gear member having a first gear to which a rotational force from the second wrist drive motor is input and a second gear with which the input gears of the plurality of crankshafts engage
Data Source
AI summary
A wrist unit of an industrial robot including an eccentric rocking-type reduction gear. The eccentric rocking-type reduction gear includes a hollow forming part forming a hollow part along the rotation center axial line; a through shaft supported rotatably at the hollow forming part and passing through the hollow part to transmit a rotation from the third wrist drive motor from a first wrist element side to a second wrist element side; a plurality of crankshafts arranged around the through shaft and having input gears at ends of the side of the first wrist element; and a gear member provided rotatably centered about the rotation center axial line, the gear member having a first gear to which a rotational force from the second wrist drive motor is input and a second gear with which the input gears of the plurality of crankshafts engage.