Compact Robot Arm Joint Sealing and Cable Isolation
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Solution Overview
Problem
Existing robotic arm joints face issues with grease infiltration into electrical components, instability of the motor input shaft, and interference between power and signal cables due to irrational structural design and inadequate sealing, leading to safety and reliability concerns.
Innovation Solution
A compact robotic arm joint design that separates the motor, harmonic reducer, and control board into different spaces, uses multiple bearings for support, incorporates sliding seals and magnetic shielding, and employs dual wiring holes for power and signal cables, along with magnetic coders to prevent contamination and interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single large wiring hole is used for power and signal cables, then the structure is simple, but electromagnetic interference occurs between cables
Solution Approach 1:
The single large wiring hole is divided into two separate wiring holes: one dedicated to power cables and another for signal cables. This segmentation prevents electromagnetic interference between power and signal transmissions while maintaining structural simplicity through standardized hole configurations.
2Stability of the object's composition
If the support member is positioned far from the motor output end, then the motor input shaft becomes unstable
Solution Approach 1:
The support member is pre-positioned at an optimal location between the motor output end and the harmonic reducer input shaft. This preliminary positioning ensures adequate support for the motor input shaft while maintaining proper mechanical alignment and transmission efficiency, preventing both instability and excessive length.
3Object-affected harmful factors
If the housing sealing is insufficient, then grease flows out and contaminates the robotic arm, but increased sealing may cause grease infiltration into electrical components
Solution Approach 1:
A sealing structure is introduced as an intermediary element between the harmonic reducer grease chamber and the motor electrical components. This sealing structure prevents grease from escaping to contaminate the robotic arm while blocking the pathway that would allow grease infiltration into electrical components, thus protecting both systems.
4Volume of stationary object
If the motor, harmonic reducer, and control board are in the same space, then the structure is compact, but grease infiltration into electrical components occurs
Solution Approach 1:
The joint unit is segmented into distinct functional spaces: a motor space containing the motor and control board, and a reducer space containing the harmonic reducer. The housing separates these spaces while maintaining overall compactness, preventing grease infiltration into electrical components through the spatial separation.
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 stability, prevents grease contamination, reduces electromagnetic interference, and ensures smooth operation, resulting in a compact and reliable robotic arm joint.
Implementation Method 1
a sliding seal member is provided in a gap between the separated housing and motor shaft. The sliding seal member comprises a sealing plastic and an O-ring
Implementation Method 2
A motor shaft is coaxially connected to the housing via a bearing A and a bearing C
Implementation Method 3
A bearing B and a bearing D are provided between left and right ends of the motor shaft and the output end
Implementation Method 4
A magnetic shielding plate is provided on the housing that separates the motor from the control board
Implementation Method 5
A rotor of the motor is connected to the motor shaft via a flat key
Data Source
AI summary
A small-scale robotic arm joint and a robot thereof are provided. In the small-scale robotic arm, multiple bearings are arranged at both ends and middle of a motor shaft; a sliding seal member is provided between a harmonic reducer and a motor; seal members are fitted on contact surfaces between a circular spline and a housing, as well as between the circular spline and the output end; a control board and the output end are hollow structures, through which cables pass; a magnetic coder is adopted to reduce a volume of the joint; additionally, a magnetic shielding plate is provided on the housing that separates the motor and the control board. Robotic arms of a robot are connected using said small-scale robotic arm joints, which are compact, smooth-operating, and safe, improve stability of a rotational axis, and prevent lubricating grease from entering the motor interior or the control board.