Shear Beam Load Cell Dynamometer Roller Torque Measurement
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Solution Overview
Problem
Existing dynamometers face challenges in accurately measuring torque due to friction in roller shaft bearings, requiring complex and costly systems for compensation, which are influenced by changes in oil viscosity, applied load, and tractive effort forces.
Innovation Solution
A dynamometer design featuring a hollow annular roller with a shear beam load cell as the sole structural connection between the roller and shaft, minimizing bearing friction influences and simplifying torque measurement by directly applying and measuring torque through the load cell.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a torque transducer is installed in the driven shaft between a shaft bearing and the load, then the dynamometer can measure torque, but the measurement accuracy deteriorates due to bearing friction influences
Solution Approach 1:
The patent extracts the torque measurement function from the traditional shaft mounting location and relocates it to the roller itself. The roller is divided into a driven portion and a measurement portion, with the torque transducer mounted on the measurement portion. This separation allows the measurement to be taken directly at the point of torque application, eliminating the interference of bearing friction that occurs in traditional shaft-mounted transducers.
Solution Approach 2:
The patent introduces a magnetic coupling mechanism as an intermediary between the roller and the torque transducer. The magnetic coupling transmits torque information without requiring direct mechanical connection through friction-prone bearings. This intermediary mechanism allows accurate torque measurement while isolating the measurement system from harmful bearing friction effects.
2Measurement precision
If complex compensation systems are used to correct bearing friction errors, then torque measurement accuracy improves, but device complexity and cost increase
Solution Approach 1:
The patent eliminates the need for complex compensation systems by extracting the torque measurement from the friction-affected shaft area and placing it directly on the roller. This structural reconfiguration removes the source of measurement error rather than requiring post-measurement compensation, thereby simplifying the overall system while maintaining high accuracy.
Solution Approach 2:
The measurement portion of the roller serves itself by directly measuring the torque at its point of application without requiring external compensation mechanisms. The design inherently compensates for bearing friction by measuring torque before it passes through the friction-prone bearing interfaces, making additional compensation systems unnecessary.
3Device complexity
If traditional shaft-mounted torque transducers are used, then the system structure is simple, but measurement accuracy deteriorates due to friction losses
Solution Approach 1:
The patent segments the roller into distinct functional portions: a driven portion that receives torque from the vehicle wheel and a measurement portion that houses the torque transducer. This segmentation allows each portion to perform its specific function optimally while minimizing interference between functions, achieving both structural simplicity and measurement accuracy.
Solution Approach 2:
The magnetic coupling acts as an intermediary that connects the driven portion to the measurement portion without requiring direct mechanical contact. This intermediary mechanism maintains a simple overall structure while enabling accurate torque measurement by isolating the transducer from friction-prone mechanical connections.
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 accuracy, reduces costs, and simplifies the dynamometer system by eliminating the need for separate measurement of braking force, while minimizing friction losses and maintaining high sensitivity and temperature compensation.
Implementation Method 1
a shear beam load cell disposed within the roller, the load cell having a first end secured adjacent to an inner surface of the roller and a second end attached to the roller shaft
Data Source
AI summary
A dynamometer includes a roller that is rotabably mounted upon a shaft with the shaft being rotatably mounted upon a support that carries the weight of the roller, the dynamometer also having a shear beam load cell disposed within the roller with a first end secured adjacent to an inner surface of the roller and a second end attached to the shaft to provide the sole structural connection between the roller and the shaft.