Bicycle Torque Sensor Using Nested Angular Displacement Detection
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Solution Overview
Problem
There is a need for a torque-measuring device that can be inserted between an inner shaft or hub and an outer structure to measure torque forces effectively, particularly for a sprocket-cassette holder or sprocket holder on a bicycle wheel, which existing technologies have not adequately addressed.
Innovation Solution
A sprocket-cassette holder that fits between a bicycle rear-wheel hub and one or more sprockets, incorporating an electrical, optical, or magnetic displacement-measuring device and circuit to measure torque by detecting relative angular displacement between the outer and inner portions of the holder, with the signal wirelessly transmitted to a display for real-time monitoring.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a torque-measuring device is inserted between the inner shaft and outer structure, then torque measurement capability is improved, but device complexity increases
Solution Approach 1:
The displacement-measuring device is nested within the hollow body of the sprocket-cassette holder, with the sensor positioned between the inner shaft and outer structure. This nesting approach allows the measurement functionality to be integrated into the existing holder structure without requiring a completely separate device, thereby improving torque measurement capability while limiting the increase in overall device complexity.
Solution Approach 2:
A displacement-measuring device acts as an intermediary between the inner shaft and outer structure, measuring the relative angular displacement that corresponds to torque. This intermediary sensor approach enables torque measurement through displacement detection rather than direct force measurement, simplifying the measurement mechanism while maintaining measurement capability.
2Measurement precision
If a displacement-measuring device is used to measure relative angular displacement, then torque measurement accuracy is improved, but ease of operation deteriorates
Solution Approach 1:
The patent replaces direct mechanical torque measurement with an optical or magnetic displacement-measuring device that detects angular displacement. This substitution improves measurement accuracy by using non-contact sensing methods, but requires the user to understand and interpret displacement data rather than direct torque readings, thereby reducing ease of operation.
Solution Approach 2:
The displacement-measuring device serves as an intermediary that converts mechanical torque into measurable displacement signals. While this improves accuracy, it adds a layer of complexity in data interpretation and signal processing that reduces ease of operation for the end user.
3Loss of information
If real-time torque monitoring is implemented, then information availability is improved, but use of energy increases
Solution Approach 1:
The displacement-measuring device continuously monitors relative angular displacement in real-time, providing continuous torque information to the user. This continuous measurement improves information availability but requires constant power supply to the sensor and signal processing circuitry, thereby increasing energy consumption.
Solution Approach 2:
The system implements real-time feedback by continuously measuring displacement and providing torque information to the user during operation. This feedback mechanism improves information availability for performance monitoring but requires sustained energy input to maintain the measurement and communication systems active throughout the cycling activity.
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 and real-time measurement of torque applied by a bicycle rider, converting it into power and energy data displayed on a user-friendly interface, providing graphical representations of current and past trips for enhanced performance monitoring.
Implementation Method 1
measuring the relative angular displacement of an outer portion of the holder in relation to an inner portion of the holder
Implementation Method 2
at least one magnetic-field generator placed on a first plane of a right section of a shaft and at least one magnetic-field detector placed in a second plane of a right section of the shaft. The detector produces a signal proportional to the torque following the relative angular shift of the field generator in relation to the detector
Data Source
AI summary
A torque-measurement device that has a rotational axis, and wherein the torque-measurement device includes an inner tubular structure, an outer tubular structure, and a plurality of ribs that each have a length dimension in a rib-length direction parallel to the rotational axis, a rib-width dimension in a width direction perpendicular to the length direction and extending radially rotational axis, and a minimum rib-thickness dimension in a thickness direction perpendicular to the length direction and perpendicular to the width direction, wherein the length dimension is greater than the width dimension and the width dimension is greater than the thickness dimension, wherein each of the plurality of ribs has a center plane that lies in the rib-length direction and the rib-width direction, and wherein a torque applied between the inner tubular structure and the outer tubular structure results in an angular displacement of inner tubular structure relative to the outer tubular structure.