Constant-Velocity Joint Assembly for Clean Torque Measurement
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Solution Overview
Problem
Existing power tools, such as nutrunners, face issues with torque measurement accuracy due to external influences and bending forces that contaminate sensor readings, particularly because the torque sensor is integrated into the angle head, leading to length extension and potential contamination.
Innovation Solution
A constant-velocity joint assembly is designed to decouple the coupling structure and torque transducer from the output shaft, allowing for variable angling at constant rotational speed, thereby reducing the impact of bending forces on torque measurements, and featuring a torque transducer with strain gauge elements on the external or internal surface of the coupling structure for accurate measurements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the torque sensor is integrated into the angle head, then torque measurement capability is provided, but the angle head length is extended and measurement accuracy is reduced due to bending forces
Solution Approach 1:
The torque transducer is extracted from the angle head and integrated into the coupling structure instead. This relocation removes the torque sensing function from the angle head, allowing the angle head to be shortened while maintaining torque measurement capability through the coupling structure's transducer.
Solution Approach 2:
The coupling structure acts as an intermediary between the output shaft and the angle head. It transmits torque while isolating the torque transducer from bending forces through the constant-velocity joint mechanism, enabling accurate torque measurement without extending the angle head length.
2Measurement precision
If the torque sensor is integrated into the angle head, then torque measurement capability is provided, but measurement accuracy is contaminated due to external influences and bending forces
Solution Approach 1:
The torque transducer is extracted from the angle head and placed in the coupling structure, removing it from the zone affected by bending forces. This extraction eliminates the harmful effect of bending force contamination on torque measurements.
Solution Approach 2:
The constant-velocity joint assembly in the coupling structure serves as a mechanical intermediary that transmits torque while filtering out bending forces. This mediator protects the torque transducer from external influences, ensuring clean torque measurement signals.
3Measurement precision
If the coupling structure and torque transducer are decoupled from the output shaft, then torque measurement accuracy is improved, but device complexity increases due to the constant-velocity joint assembly
Solution Approach 1:
The coupling structure is designed to perform multiple functions: it provides the constant-velocity joint mechanism for angular misalignment compensation, houses the torque transducer for torque measurement, and transmits power from the output shaft. This multi-functionality reduces overall device complexity by combining what could be separate components.
Solution Approach 2:
The torque transducer is merged with the coupling structure, and the constant-velocity joint assembly is integrated into the same component. This merging of functions into a single integrated assembly reduces the number of separate parts and simplifies the overall device architecture.
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 enhances torque measurement accuracy by isolating the torque sensor from bending forces, providing more reliable readings and minimizing the length impact, while also allowing for efficient power and signal transmission using a slip ring or alternative methods.
Implementation Method 1
the torque transducer comprises strain gauge elements
Data Source
Figure 1
Figure 2~3
Figure 4
AI summary
A constant-velocity joint assembly (1) comprising: an output shaft (7), and a coupling structure (5) configured to drive the output shaft (7), wherein the output shaft (7) and the coupling structure (5) form a first joint configured to enable angling of the output shaft (7) relative to the coupling structure (5) at constant rotational speed, wherein the coupling structure (5) is provided with a torque transducer (5f) configured to detect a torque acting on the coupling structure (5) provided by the output shaft (7).