Bottom Bracket Torque Measurement via Chainring Shaft
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Solution Overview
Problem
Existing bottom bracket designs face challenges in accurately measuring torque for each pedal crank due to difficulties in sensor positioning, especially when the shaft is formed by two hollow component shafts joined together, which increases assembly costs and complexity.
Innovation Solution
A bottom bracket design featuring a chainring carrier connected to a chainring shaft, which is subsequently fastened to a solid or hollow shaft, allowing for a screw connection and simplified assembly, with magnetized areas and sensors to detect torque, enabling precise measurement of torques introduced by each pedal crank.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the shaft is formed by two hollow component shafts joined together, then torque measurement capability is improved, but assembly complexity and cost increase
Solution Approach 1:
The bottom bracket is divided into modular components: a shaft module (solid or hollow) and a chainring carrier module (with or without integrated chainring). This segmentation allows flexible assembly where the chainring carrier is pre-assembled with the chainring, then mounted to the shaft as a complete unit, reducing overall assembly complexity while maintaining torque measurement capabilities through magnetized portions on the shaft.
2Stability of the object's composition
If the chainring carrier is joined fixedly to the hollow shaft, then structural stability is improved, but assembly ease deteriorates
Solution Approach 1:
The chainring carrier is pre-assembled with the chainring in a preliminary assembly step, creating a stable sub-assembly. This pre-assembled unit is then mounted to the shaft as a complete package, ensuring structural stability of the chainring carrier-shaft connection while simplifying the overall assembly process by reducing the number of separate mounting operations required.
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 simplifies assembly, ensures accurate and positionally correct mounting of the chainring carrier, and allows for direct detection of torques introduced by each pedal crank, facilitating the calculation of total torque and power exerted by the operator.
Implementation Method 1
to form a magnetized portion on the body of the shaft so that when applying or altering a torque, the magnetized portion alters its magnetization due to the magnetostrictive effect
Data Source
AI summary
A bottom bracket, which has a shaft, a first pedal crank, which is connected in a rotationally fixed manner to the shaft, a second pedal crank, which is connected in a rotationally fixed manner to the shaft, and a chainring carrier, which is connected to the shaft. The object of providing a bottom bracket with a chainring carrier that is easy to assemble is achieved by the chainring carrier being connected in a rotationally fixed manner to a chainring shaft and by the chainring shaft being connected in a rotationally fixed manner to the shaft.