Bicycle Start-Off Gear Shifting for Steep and Low-Speed Launches
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Bicycles with electrical propulsion means face difficulties in shifting gears at a standstill, especially on steep terrain, leading to inefficient power utilization and increased physical effort for the rider.
Innovation Solution
A method for automatically shifting into a suitable gear based on current speed, inclination angle, crank torque, and gear comparison, using sensors and a control device to optimize cadence between 60-120 rpm, enabling effortless starting-off assist.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the rider manually shifts the bicycle gear at a standstill on steep terrain, then the gear can be changed to optimal starting-off gear, but the rider must lift the rear wheel which becomes very difficult due to ambient conditions and bicycle weight
Solution Approach 1:
The gear shifting system performs the shifting operation automatically without requiring manual intervention from the rider. The control device monitors sensor data (speed, inclination angle, crank torque, current gear) and autonomously actuates the derailleur gear to shift into the optimal starting-off gear, making the system serve itself rather than requiring the rider to manually lift the wheel and shift gears
Solution Approach 2:
The manual mechanical action of lifting the rear wheel and shifting gears is replaced by an automated control system that uses sensors and a control device to monitor riding conditions and automatically actuate the gear shifting mechanism, substituting the mechanical rider action with an automated electromechanical system
2Power
If the rider is in an unfavorable gear when starting off on a steep hillside, then the full system power is not available, but manual gear shifting at standstill is difficult or impossible
Solution Approach 1:
The control device performs preliminary assessment of riding conditions (speed, inclination angle, crank torque, current gear) before the rider attempts to start off, and proactively shifts the gear into the optimal starting-off gear in advance, ensuring full system power is available when needed without requiring difficult manual intervention at the moment of starting
3Ease of operation
If automatic gear shifting is implemented, then gear shifting at standstill becomes easy, but the device complexity increases due to sensors and control logic
Solution Approach 1:
The control device performs multiple functions: it monitors speed, inclination angle, crank torque, and current gear; it determines the optimal starting-off gear based on these parameters; and it actuates the gear shifting mechanism. By consolidating these multiple functions into a single control device, the patent reduces overall system complexity compared to having separate systems for each function
Data Source
AI summary
A method for automatically shifting into a suitable gear of a bicycle transmission of a bicycle for starting off, the suitable gear enabling a cadence in a range from 60 to 120 rotations per minute, the method being carried out when starting-off assist is activated. The method includes automatically shifting into the suitable gear when, simultaneously: a current speed of the bicycle reaches or falls below a speed threshold value, a current crank torque of the bicycle reaches or exceeds a crank torque threshold value, a current gear of the bicycle deviates from a gear threshold value, and either i) the current inclination angle of the bicycle reaches or exceeds a first inclination angle threshold value, or ii) the current inclination angle of the bicycle falls below a second inclination angle threshold value.