Robot Joint Torque Sensor Sealing to Minimize Secondary Force Flows
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Solution Overview
Problem
Existing robot joint designs with integrated torque sensors face challenges in achieving high sealing effectiveness without distorting torque measurements due to secondary force flows from seal friction, which impairs measurement accuracy.
Innovation Solution
The solution involves separating seals for the transmission and main bearing, with a dynamic contact seal between the transmission and joint torque sensor, and a contactless seal between the links, minimizing friction and maintaining accurate torque measurement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a seal is integrated into the robot joint to seal the gap between links, then sealing effectiveness is improved, but measurement accuracy deteriorates due to secondary force flows from seal friction
Solution Approach 1:
The seal is segmented into two separate seals: a first seal for sealing the transmission casing and a second seal for sealing the gap between links. This segmentation allows each seal to be optimized for its specific function, with the second seal positioned to minimize interference with torque measurement while maintaining sealing effectiveness.
Solution Approach 2:
A seal carrier is introduced as an intermediary component to mount the second seal. The seal carrier is arranged on the output shaft and provides a mounting surface for the second seal, positioning it to seal the gap between links while minimizing secondary force flows that could affect torque measurement accuracy.
2Reliability
If a dynamic contact seal is used to seal the transmission casing, then sealing effectiveness is improved, but friction increases causing measurement distortion
Solution Approach 1:
The sealing function is divided into two separate seals with distinct functions: the first seal handles transmission casing sealing, while the second seal handles gap sealing. This segmentation allows optimization of each seal's position and design to minimize harmful secondary force flows while maintaining effective sealing.
Solution Approach 2:
The second seal is specifically positioned at a location where it can seal the gap between links effectively while minimizing its impact on torque measurement. The seal carrier allows precise positioning of the second seal to achieve optimal local sealing quality without generating significant secondary force flows.
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 approach ensures a complete sealing of the transmission while minimizing secondary force flows, allowing for precise torque measurement without significant distortion, even in sensitive robots.
Implementation Method 1
a dynamic contact seal, which seals off the transmission casing in a lubricant-tight manner
Implementation Method 2
a gap, which is determined by the main bearing arrangement, between the upstream link and the downstream link is sealed off in particular in a dust-tight manner by means of the further dynamic, in particular contactless, seal
Data Source
AI summary
A robot arm has a transmission output-side mating running surface on which a dynamic contact seal that seals off the transmission casing in a lubricant-tight manner is seated. A gap is determined by a main bearing arrangement between an upstream link and a downstream link, to which an output flange of a joint torque sensor is coupled, is sealed off by means of a further dynamic seal, with the objective of increasing the accuracy of the torque measurement by optimizing the secondary force flows.