E-Bike Hub Torque Sensor PCB Layout for Slim Rear-Wheel Drives
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing electric bicycles face challenges in providing a reliable and efficient drive system with high power transfer, particularly due to limitations in sensor systems that affect riding performance.
Innovation Solution
A sensor unit for an electric bicycle drive device featuring a hub axle, a housing element, and separate printed circuit boards to determine torque, utilizing a magnetostrictive measuring principle with a measuring sleeve and Hall sensors, allowing for a slim and space-saving design that integrates torque sensors effectively.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a torque sensor system is integrated into the rear wheel hub drive, then riding performance and power transmission are improved, but the device complexity and structural space requirements increase
Solution Approach 1:
The sensor unit is divided into two separate printed circuit boards: a first printed circuit board with sensor technology and evaluation electronics for torque determination, and a second printed circuit board with coils and Hall sensor. This segmentation allows each board to have specialized functions, reducing interference and optimizing performance while maintaining a compact overall structure.
Solution Approach 2:
The two printed circuit boards are arranged on opposite sides of the housing element and surround the hub axle at least in sections with respect to the axis of rotation. This spatial arrangement in three dimensions enables efficient use of available space, creating a slim drive device structure while accommodating all necessary sensor components.
2Measurement precision
If separate printed circuit boards are used for torque determination, then measurement precision and reliability are improved, but the device complexity increases
Solution Approach 1:
The sensor unit separates measurement functions across two printed circuit boards: the first board handles sensor technology and evaluation electronics, while the second board contains coils and Hall sensors. This functional segmentation improves measurement precision by isolating sensitive measurement components from potential interference sources, while the modular design manages complexity through clear functional separation.
3Length of moving object
If the sensor unit is designed with a slim structure, then integration into the rear wheel hub is improved, but the space available for sensor components is reduced
Solution Approach 1:
The sensor components are arranged in a three-dimensional configuration around the hub axle, with printed circuit boards positioned on opposite sides of the housing element. This spatial arrangement allows the drive device to maintain a slim external profile while accommodating sufficient sensor component volume through efficient use of internal space in multiple dimensions.
Solution Approach 2:
The printed circuit boards surround the hub axle and are integrated within the housing element structure. This nested arrangement allows sensor components to be compactly organized around the central rotation axis, achieving a slim overall structure while providing adequate space for all necessary sensor elements.
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 solution enhances riding performance by improving power transmission and integration of torque sensors, preventing measurement interference from the motor, and enabling efficient heat dissipation, resulting in a reliable and efficient drive system.
Implementation Method 1
A torsional moment twists the measuring sleeve so that the magnetic field in the measuring sleeve changes. Such a magnetic field change is proportional to the torque
Implementation Method 2
the other printed circuit board is equipped, for example, only with one or more coils and a Hall sensor
Data Source
AI summary
In an embodiment a sensor unit includes a hub axle connectable to an electric motor of a drive device of an electric bicycle, a housing element rotatable about an axis of rotation and configured to form a part of a motor housing for the electric motor, wherein the housing element is coupled to the hub axle and comprises an opening through which the hub axle extends and a first printed circuit board and a second printed circuit board configured to determine a torque of a rider of the electric bicycle and are coupled to one another in terms of signal technology, wherein the printed circuit boards are coupled to the hub axle on opposite sides of the housing element and at least partially surround the hub axle with respect to the axis of rotation.