E-Bike Power Transmission Layout for Integrated Torque and Rotation Sensing
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Solution Overview
Problem
Existing power transmission units for electric bicycles face challenges in effectively utilizing space due to the separate placement of torque sensors and rotation detectors, leading to complex interconnections and increased size.
Innovation Solution
A power transmission unit configuration where the torque detection unit and detection target overlap when viewed perpendicularly to the rotational axis, allowing for closer arrangement and simplified interconnection, along with a transmission member that transmits rotational power from the input shaft to the output structure, facilitating efficient space use.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the torque sensor and rotation detector are arranged at separate positions along the axis of the crankshafts, then each component can be independently positioned for optimal function, but the interconnection between them becomes too complicated and space utilization is reduced
Solution Approach 1:
The patent combines the torque sensor and rotation detector into a single integrated detection unit. The torque detection unit includes a magnetostriction generator unit formed on the outer peripheral surface of the input structure and a coil wound around it, while the rotation detector uses a detection target that rotates with the input structure. This merging eliminates the need for separate positioning and complex interconnections, simplifying the overall structure while maintaining detection functionality.
Solution Approach 2:
The detection unit serves multiple functions simultaneously: it detects both torque (through the magnetostriction effect) and rotation state (through the rotating detection target). This multi-functionality allows a single integrated unit to replace what would traditionally require separate components, reducing structural complexity while maintaining comprehensive detection capabilities.
2Measurement precision
If the torque sensor and rotation detector are arranged at separate positions, then each detector can be optimized for its specific function, but the overall unit size increases and space inside the unit is not effectively utilized
Solution Approach 1:
The detection target for rotation detection is positioned within the spatial envelope of the torque detection unit. When viewed perpendicularly to the rotational axis, the detection target overlaps with the torque detection unit, allowing the rotation detection functionality to be nested within the same radial space as the torque detection, thereby minimizing the overall unit size.
Solution Approach 2:
The patent transitions from arranging detectors along the axial dimension to utilizing the radial dimension for overlapping placement. By positioning the detection target such that it overlaps with the torque detection unit when viewed perpendicularly to the rotational axis, the design effectively uses the radial space to accommodate multiple detection functions without increasing axial length.
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 configuration enables effective space utilization within the unit, simplifies connections, and reduces the overall size of the power transmission system while maintaining accurate torque detection and rotational state monitoring.
Implementation Method 1
the torque sensor is implemented as a magnetostrictive sensor, which includes a magnetostriction generator unit formed on an outer peripheral surface of the human driving force transmission body
Data Source
AI summary
A motor unit comprises a case, a motor, an input shaft, an output structure, a transmission member, a first tooth portion, a torque detection unit, and a rotator. The case includes a first supporting portion located at a first end of an inside of the case in the axial direction and rotatably supporting the rotator, and a second supporting portion located at a second end of the inside of the case in the axial direction and rotatably supporting the rotator. The rotator includes a second tooth portion meshing with the first tooth portion. A meshing part of the first tooth portion with the second tooth portion is arranged between the input shaft and the rotator in a direction perpendicular to the axis and is arranged radially outward of the rotator than the first supporting portion and the second supporting portion.