Torque Measurement Assembly Using Deformable Rings
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Solution Overview
Problem
Existing torque measurement systems for rotating shafts in mechanical systems, such as motor-assisted bicycles, lack accuracy in measuring torque applied from specific sources, which affects the optimization of performance and efficiency.
Innovation Solution
A torque measurement assembly comprising a disk coupled to a motor, a first ring and a second ring with deformable members between them, and a sensor unit to measure rotational displacement, allowing for precise measurement of torque applied to a shaft by detecting the rotational angle shift between the rings.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional torque measurement systems are used, then the system structure is simple, but the measurement precision is insufficient
Solution Approach 1:
The measurement assembly is segmented into distinct functional components: a first ring coupled to the motor, a second ring coupled to the shaft, and deformable members connecting them. This segmentation allows each component to perform its specific function independently while contributing to the overall measurement accuracy without excessive complexity.
Solution Approach 2:
Deformable members serve as intermediary elements between the first ring and second ring. These members transmit torque while undergoing measurable deformation, acting as a mediator that converts mechanical torque into a detectable rotational displacement that can be measured by the sensor unit.
2Measurement precision
If deformable members are introduced to improve measurement accuracy, then the torque measurement precision improves, but the device complexity increases
Solution Approach 1:
The deformable members are designed as flexible elastic elements that can deform under torque loading. This flexibility allows them to undergo measurable angular displacement while maintaining structural integrity, enabling accurate torque measurement through the relationship between deformation and applied torque.
Solution Approach 2:
The sensor unit provides feedback by continuously measuring the rotational displacement between the first and second rings. This displacement data is directly related to the torque applied to the shaft, creating a feedback mechanism that enables accurate torque determination through measurement of the deformable members' angular deformation.
3Measurement precision
If a sensor unit is added to measure rotational displacement, then the measurement precision improves, but the device complexity and cost increase
Solution Approach 1:
The invention replaces direct mechanical torque sensing with an optical or magnetic measurement system. The sensor unit measures rotational displacement of the rings rather than directly measuring mechanical forces, substituting a more precise non-contact measurement method for traditional mechanical torque sensors.
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 system provides accurate torque measurement, enabling better control of motor output in motor-assisted bicycles, enhancing their performance and operational efficiency.
Implementation Method 1
one or more deformable members coupled between the disk and the shaft, each deformable member including a pair of ends and a curved body extending between the pair of ends. For each deformable member, one of the pair of ends is coupled to the shaft and the other of the pair of ends is coupled to the disk such that a rotation of the shaft relative to the disk about the central axis is configured to cause the curved body to bend
Implementation Method 2
a sensor unit configured to measure a rotational displacement between the first ring and the second ring about the central axis
Data Source
AI summary
A measurement assembly for determining a torque applied to a shaft including a disk coupled to a motor such that the motor is to drive rotation of the disk about a central axis. The measurement assembly also includes a first ring and second ring coupled to the disk and the shaft, respectively, and a sensor unit to measure a rotational displacement between the first and second rings about the central axis. The measurement assembly further includes one or more deformable members coupled between the disk and the shaft, each including a pair of ends and a body extending therebetween. For each deformable member, one of the ends is coupled to the shaft and the other end is coupled to the disk such that a rotation of the shaft relative to the disk about the central axis is to cause the deformation of the body.