Bicycle Hub Torque Sensing With Freewheel and Stationary Sensors
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Solution Overview
Problem
Existing bicycle hub systems with integrated electric motors require complex sensors and control electronics for torque measurement, leading to increased manufacturing complexity and maintenance efforts.
Innovation Solution
A hub arrangement featuring a static hollow shaft with rotatable drive arrangements, a freewheel mechanism, and a torque sensor system using spring-loaded end stops and magnetic signaling elements, allowing for simplified torque measurement without rotating sensors or slip rings.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If rotating sensors or slip rings are used for torque measurement, then torque can be measured, but device complexity and maintenance requirements increase
Solution Approach 1:
The patent extracts the sensor system from the rotating components and places it on the stationary housing. The magnetic field signaling elements remain on rotating components but the actual sensing occurs stationary, eliminating the need for rotating sensors or slip rings while maintaining torque measurement capability.
Solution Approach 2:
The patent introduces magnetic field signaling elements as an intermediary between the rotating drive components and the stationary sensor system. These magnetic elements transmit rotational position information through the housing without requiring physical electrical connections, simplifying the overall system architecture.
2Measurement precision
If rotating sensors with wireless transmission or slip rings are used, then torque measurement is achieved, but manufacturing complexity increases
Solution Approach 1:
The sensor system is extracted from the rotating assembly and positioned on the stationary housing, eliminating the need for complex rotating sensor assemblies or slip ring mechanisms. This significantly simplifies manufacturing as stationary sensors are easier to install and align than rotating equivalents.
Solution Approach 2:
The patent replaces mechanical sensor systems (rotating sensors or slip rings) with a magnetic field-based signaling system. The magnetic signaling elements on rotating components interact with stationary sensors through the housing, substituting complex mechanical electrical connections with simpler magnetic field coupling.
3Measurement precision
If complex sensor arrangements are used for torque measurement, then accurate control is achieved, but maintenance efforts increase
Solution Approach 1:
By extracting the sensor system from rotating components and placing it on the stationary housing, the patent eliminates wear-prone rotating sensor elements and slip rings. The stationary sensors have no moving parts, significantly reducing maintenance requirements while maintaining accurate torque measurement capability.
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 efficient and low-maintenance torque sensing in bicycle hubs, reducing complexity and maintenance needs while providing accurate control of electric motors.
Implementation Method 1
the receiving element is rotatably supported against the drive element with a spring-loaded end stop such that the receiving element may rotate with respect to the drive element about a predetermined angle of rotation
Implementation Method 2
a first signaling element arranged on the receiving element, a second signaling element arranged on the drive element, a first sensor configured to sense the first signaling element, and to provide a respective first output signal, a second sensor configured to sense the second signaling element
Data Source
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AI summary
The present disclosure provides a hub arrangement comprising a static hollow shaft arrangement, a first drive arrangement rotatably arranged on the static hollow shaft arrangement, a second drive arrangement arranged rotatably on the first drive arrangement, wherein the second drive arrangement comprises a receiving element, and a drive element, wherein the receiving element is rotatably supported against the drive element with a spring-loaded end stop such that the receiving element may rotate with respect to the drive element about a predetermined angle of rotation, and a freewheel arrangement that is coupled to the first drive arrangement, and the receiving element of the second drive arrangement, and that allows the receiving element of the second drive arrangement to rotate with regard to the first drive arrangement in a first direction of rotation, and that blocks the receiving element of the second drive arrangement from rotating with regard to the first drive arrangement in a second direction of rotation that is opposite to the first direction of rotation. The hub arrangement further comprises a torque sensor arrangement that comprises a first signaling element arranged on the receiving element, a second signaling element arranged on the drive element, a first sensor configured to sense the first signaling element, and provide a respective first output signal, a second sensor configured to sense the second signaling element, and provide a respective second output signal, a processing unit coupled to the first sensor, and the second sensor, wherein the processing unit is configured to determine a torque transferred via the freewheel arrangement to the receiving element based on the first output signal, and the second output signal, and to output the determined torque.