Thread-On Freewheel Torque Sensing for Accurate Pedaling Force
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Solution Overview
Problem
Existing torque sensors installed inside motors are affected by rider weight and rotation angle, leading to inaccurate measurement of pedaling force.
Innovation Solution
A dynamic torque sensing device in a thread-on freewheel structure, comprising a thread-on freewheel sensing body, stationary housing, and a deformation sensing sensor, which includes a torque sensing Hall and magnet, with inductor primary and secondary control circuits and electromagnetic shields, allowing for precise measurement of pedaling force without interference from rider weight or vehicle unladen weight.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the torque sensor is installed inside the motor, then the wiring and assembly of the whole vehicle become easier and cleaner, but the signal variation of the torque sensor is affected by rider weight and rotation angle, leading to inaccurate measurement of pedaling force
Solution Approach 1:
The sensing body is divided into three separate portions: a relatively stationary portion, a relatively rotating portion, and an intermediary portion. This segmentation allows the sensor to measure torque on the rotating portion while the stationary portion remains unaffected by rider weight and rotation angle, thus resolving the contradiction between ease of installation and measurement precision.
2Adaptability or versatility
If the sensor measures torque while affected by rider weight and rotation angle, then the sensor can be installed inside the motor, but the sensor cannot measure the true pedaling force
Solution Approach 1:
The measurement function is extracted from the motor installation environment and placed on the rotating sensing body. By positioning the torque sensor on the rotating portion that is mechanically isolated from the stationary housing, the system achieves accurate pedaling force measurement while maintaining installation flexibility in the motor.
3Measurement precision
If the sensing body is designed with stationary and rotating portions, then the device can measure precise pedaling force, but the device complexity increases
Solution Approach 1:
The stationary and rotating portions are merged through the intermediary portion that connects them mechanically. This integration allows the complex functionality of measuring torque on a rotating body while maintaining a relatively simple overall structure that can be manufactured as a single piece or assembled from few components.
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
Enables accurate measurement of pedaling force by isolating the sensing device from external forces, providing a modular design with higher compatibility for assembly on bicycles and motors.
Implementation Method 1
The sensor is a deformation sensing sensor which is disposed in the thread-on freewheel sensing body intermediary portion
Implementation Method 2
The sensor includes a torque sensing Hall and a torque sensing magnet
Data Source
AI summary
A dynamic torque sensing device of a thread-on freewheel structure includes a thread-on freewheel sensing body (1), a stationary housing (2) and a sensor (12). The thread-on freewheel sensing body and the stationary housing are rotatable relative to each other, and the sensor is configured to sense a torque of the thread-on freewheel sensing body. The thread-on freewheel sensing body includes a thread-on freewheel sensing body relatively stationary portion (101), a thread-on freewheel sensing body relatively rotating portion (102) and a thread-on freewheel sensing body intermediary portion (103). The thread-on freewheel sensing body relatively stationary portion, the thread-on freewheel sensing body intermediary portion and the thread-on freewheel sensing body relatively rotating portion are sequentially arranged along an axial direction of the thread-on freewheel sensing body. The thread-on freewheel sensing body intermediary portion is configured to connect the thread-on freewheel sensing body relatively stationary portion to the thread-on freewheel sensing body relatively rotating portion.