Spoke-Type Bicycle Crank Torque Sensor for Sensitive Strain Detection
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Solution Overview
Problem
Resistance strain gauges attached to the front of a bicycle spoke bar fail to easily sense the deformation of the spoke-type elastomer due to the large area, leading to insensitive sensing of pedaling force.
Innovation Solution
A wireless transmission bicycle crankset spoke-type torque sensor with a five-way-end stationary circuit housing and rotating torque circuit board, incorporating power source coils, resistance strain gauges, Hall elements, and magnetic rings, allowing the strain gauges to be attached to the side walls of spoke bars for precise deformation sensing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of moving object
If resistance strain gauges are attached to the front of the spoke bar, then the sensing area is increased, but the sensitivity to deformation is reduced
Solution Approach 1:
The patent applies local quality by attaching resistance strain gauges to the side walls of spoke bars rather than the front surface. This localized placement on the side walls (where deformation occurs during hub and rim rotation in opposite directions) provides both sufficient sensing area and high sensitivity to bending deformation, resolving the contradiction between area and sensitivity.
2Area of stationary object
If resistance strain gauges are attached to the front of the spoke bar, then the installation area is increased, but the deformation detection capability is reduced
Solution Approach 1:
The patent places strain gauges on the side walls of spoke bars where bending deformation occurs during operation. This localized placement provides adequate installation area while maximizing deformation detection capability, as the side wall location experiences the greatest strain during hub and rim rotation in opposite directions.
Solution Approach 2:
The patent transitions from attaching strain gauges to the front surface (two-dimensional plane) to attaching them on the side walls (different spatial dimension). This dimensional change allows the strain gauges to be positioned where deformation is most pronounced, improving detection capability while maintaining sufficient installation area.
3Measurement precision
If the spoke-type elastomer structure is used with hub and rim rotating in opposite directions, then the deformation of spoke bars is enhanced, but the complexity of the sensing system increases
Solution Approach 1:
The patent utilizes the natural deformation of spoke bars when the hub and rim rotate in opposite directions to generate the sensing signal. The mechanical deformation itself serves the sensing function, eliminating the need for additional active sensing components or complex signal generation mechanisms, thus reducing overall system complexity while enhancing deformation magnitude for detection.
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 sensor enhances sensitivity by detecting changes in resistance values as the spoke bars bend, improving the accuracy of pedaling force detection through wireless transmission.
Implementation Method 1
a power source transmitting coil, arranged on the stationary circuit board; a power source induction receiving coil, arranged on the rotating torque circuit board
Implementation Method 2
the resistance strain gauges fail to easily sense the deformation of the spoke-type elastomer, leading to insensitive sensing
Implementation Method 3
a Hall element and a magnetic ring, where the stationary circuit board is arranged inside the five-way-end stationary circuit housing; the power source transmitting coil, the sensor torque signal receiving circuit and the Hall element are arranged on the stationary circuit board
Data Source
AI summary
Disclosed is a wireless transmission bicycle crankset spoke-type torque sensor, which belongs to the field of bicycles. The torque sensor comprises a five-way-end stationary circuit housing. The structural feature of the torque sensor lies in further comprising a power source transmitting coil, a power source induction receiving coil, resistance strain gauges, a stationary circuit board, a sensor torque signal receiving circuit, a spoke-type elastomer, a sensor torque signal transmitting circuit, a power source induction receiving modulation circuit unit, a rotating torque circuit board, a Hall element and a magnetic ring, wherein the stationary circuit board is arranged inside the five-way-end stationary circuit housing; the power source transmitting coil, the sensor torque signal receiving circuit and the Hall element are arranged on the stationary circuit board; the rotating torque circuit board and the resistance strain gauges are both arranged on the spoke-type elastomer.