Robot Arm Driving Unit With Nested Transmission Shafts
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Solution Overview
Problem
Existing robot arm driving units face challenges in efficiently rotating hollow members relative to each other about a rotary axis, particularly in reducing the offset of the motor with respect to the reducer's central axis, which affects the design and assembly of the robot arm components.
Innovation Solution
A driving unit comprising a bracket, a motor, a reducer, and a power transmission mechanism with a driving shaft, where the motor's shaft is positioned closer to the rotary axis than the driving shaft, utilizing a first and second transmission mechanism to transmit rotation, and a sealing member to maintain a lubricated sealed space, allowing for reduced offset and efficient rotation of the robot arm components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the motor shaft is positioned closer to the rotary axis than the driving shaft, then the outer diameter of the wrist shaft casing is minimized, but the device complexity increases due to the additional driving shaft and transmission mechanisms
Solution Approach 1:
The patent positions the motor shaft and driving shaft at different radial distances from the rotary axis, utilizing the radial dimension to accommodate both shafts within the limited space. This dimensional arrangement allows the motor shaft to be closer to the rotary axis while the driving shaft operates at a larger radius, enabling compact overall design without excessive complexity
Solution Approach 2:
The transmission mechanisms are nested within the bracket structure, with the first transmission mechanism positioned between the motor shaft and driving shaft, and the second transmission mechanism positioned between the driving shaft and reducer input shaft. This nesting arrangement minimizes the outer diameter of the wrist shaft casing while organizing the transmission components in a compact, hierarchical manner
2Object-affected harmful factors
If a driving shaft is introduced between the motor shaft and reducer input shaft, then the load on wires routed through hollow members is reduced, but the device complexity increases
Solution Approach 1:
The driving shaft acts as an intermediary component between the motor shaft and the reducer input shaft. By introducing this intermediate element with associated transmission mechanisms, the patent distributes and reduces the load on wires routed through hollow members, while organizing the complexity into manageable modular transmission stages
Solution Approach 2:
The transmission system is segmented into distinct functional stages: the first transmission mechanism between the motor shaft and driving shaft, and the second transmission mechanism between the driving shaft and reducer input shaft. This segmentation allows each transmission stage to handle a portion of the total load, reducing wire load while distributing the complexity across separate, manageable components
Data Source
AI summary
A driving-unit that rotates a first-member and a second-member constituting a robot-arm about a rotary-axis. The driving-unit includes: a bracket fixed to the first-member and including a first-hollow-hole penetrating along the rotary-axis; a motor fixed to the bracket and accommodated in the first-member; a reducer that connects the bracket and the second-member rotatable about the rotary-axis and that includes a second-hollow-hole penetrating along the rotary-axis; and a driving power transmission mechanism accommodated in the bracket and transmitting a rotation of the motor to the reducer. The driving power transmission mechanism includes a driving-shaft, a first-transmission-mechanism that transmits the rotation of the motor to the driving-shaft, and a second-transmission-mechanism that transmits a rotation of the driving-shaft to an input-shaft of the reducer. A distance between a shaft of the motor and the rotary-axis is shorter than a distance between the driving-shaft and the rotary-axis.