E-Bike Torque Clutch for Integrated Freewheel Reliability
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Solution Overview
Problem
Existing torque-transmitting arrangements in muscle-power-operated vehicles with auxiliary motors, such as e-bikes, require redundant electric systems for reliability and freewheel functions, leading to complexity and potential failures, especially in harsh environments.
Innovation Solution
A mechanical clutch system that transmits torque from the auxiliary motor shaft to the output shaft only when the muscle-power input shaft rotates in the drive direction, and prevents torque transmission when rotating counter to the drive direction, integrating both freewheel functions into a single unit, thus eliminating the need for separate freewheels and reducing reliance on electric systems.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If redundant electric systems are used for reliability, then system reliability improves, but device complexity increases
Solution Approach 1:
The patent replaces electric sensors and control systems with a purely mechanical clutch mechanism that automatically engages and disengages based on rotation direction. The mechanical clutch uses spring-loaded clamping elements that are pressed against the output shaft when rotation occurs in the drive direction, and released when rotation stops or reverses, eliminating the need for electric sensors, controllers, and power supply systems while maintaining reliable freewheel functionality
Solution Approach 2:
The mechanical clutch system is self-regulating and automatically responds to rotation direction without external control. The spring-loaded clamping elements engage or disengage based solely on the mechanical motion itself, making the system self-service and eliminating the need for redundant electric monitoring and control systems
2Reliability
If separate freewheels are installed for both input shafts, then freewheel function reliability improves, but device complexity increases
Solution Approach 1:
The patent merges the freewheel functions for both the first and second input shafts into a single mechanical clutch mechanism. The same clamping elements that engage the output shaft during forward rotation automatically prevent backward rotation and concomitant motor rotation, providing both freewheel functions simultaneously with one device instead of requiring separate freewheels for each input shaft
Solution Approach 2:
The mechanical clutch serves multiple functions simultaneously: it transmits torque from the first input shaft to the output shaft during forward rotation, prevents the output shaft from rotating backward when the first input shaft rotates in reverse, and prevents the second input shaft from rotating the output shaft when the motor is inactive. This multi-functionality eliminates the need for separate freewheel devices
3Measurement precision
If electric systems are used for torque detection and motor control, then control precision improves, but susceptibility to faults increases
Solution Approach 1:
The patent replaces electric torque sensors and control systems with a direct mechanical coupling system. The mechanical clutch provides automatic torque transmission or disengagement based purely on mechanical motion, eliminating electronic components that are susceptible to faults from moisture, temperature extremes, and cable breaks, while maintaining sufficient control precision for the application
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 mechanical clutch system ensures reliable inactivation of auxiliary motor support, provides a compact and inexpensive construction, and maintains freewheel functionality without the need for additional freewheels, enhancing reliability and reducing the risk of system failures in adverse conditions.
Implementation Method 1
a mechanical clutch which is designed to transmit a torque from the second input shaft to the output shaft if, at the first input shaft, a torque prevails which acts in a drive direction of rotation on the output shaft
Data Source
AI summary
A torque-transmitting arrangement for the drive train of a muscle-power-operated vehicle with auxiliary motor includes an output shaft, a first input shaft for the transmission of a torque generated by muscle power to the output shaft, a second input shaft for the transmission of a torque generated by the auxiliary motor to the output shaft, and a freewheel function, which prevents a user from having to concomitantly rotate the auxiliary motor when the auxiliary motor is inactive. A mechanical clutch transmits a torque from the second input shaft to the output shaft if, at the first input shaft, a torque prevails which acts in a drive direction of rotation on the output shaft, and transmits no torque from the second input shaft to the output shaft if, at the first input shaft, a torque prevails which acts on the output shaft counter to the drive direction of rotation.