E-Bike Power Transmission Layout for Integrated Torque Detection
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Solution Overview
Problem
Existing power transmission units for electric bicycles are inefficient in utilizing space, with torque sensors and rotation detectors often placed at separate positions along the crankshaft axis, complicating their interconnection and hindering effective use of internal space.
Innovation Solution
A power transmission unit design where the torque detection unit is placed on the outer periphery of the input structure, and the detection target rotates with or interlocks with the input structure, allowing the detection unit to detect the rotational state of the detection target, with parts overlapping perpendicularly to the rotational axis, facilitating closer arrangement and efficient space utilization.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the torque sensor and rotation detector are arranged at separate positions along the crankshaft axis, then the detection functions are achieved, but the interconnection becomes complicated and space utilization is reduced
Solution Approach 1:
The patent combines the torque sensor and rotation detector into a single integrated detection unit that rotates together with the crankshaft. This merging of previously separate detection components eliminates the need for complex interconnections between separately positioned sensors and simplifies the overall system architecture while maintaining reliable detection of both torque and rotational state.
2Reliability
If the torque sensor and rotation detector are arranged at separate positions along the crankshaft axis, then the detection functions are achieved, but the space utilization inside the unit is reduced
Solution Approach 1:
The patent merges the torque sensor and rotation detector into a single rotating detection unit that is positioned at one location on the crankshaft. This integration significantly improves space utilization by eliminating the need for separate sensor positions and their associated interconnection pathways, allowing more efficient use of the available internal space within the power transmission unit.
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 simplifies the interconnection of detection components, reduces the overall size of the unit, and enhances space utilization within the electric bicycle, improving the integration and functionality of the power transmission system.
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 and a coil wound around its outer periphery
Data Source
AI summary
A power transmission unit is used for generating auxiliary driving force for an electric bicycle, and includes a motor, an input structure, a speed reducer, a case, a bearing, and a bearing support portion. The motor includes a motor shaft. The input structure includes an input shaft and configured to rotate along with the input shaft, the input shaft being caused to rotate by external force transmitted thereto. Thea speed reducer mechanism is configured to transmit a rotational power of the motor shaft while reducing a rotational speed. The case houses the motor, the input structure, and the speed reducer mechanism. The case includes a first divided part and a second divided part. The bearing is located inside the case. The bearing supporting portion, to which the bearing is attached, supports the speed reducer mechanism. The bearing supporting portion is attached to the first divided part.