Bicycle Transmission Shift Timing for Synchronized Clutch Engagement
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Bicycle manual transmissions with auxiliary motors face challenges in smooth gear changes, particularly when simultaneous switching of two couplings is required, leading to risks of intermediate steps and empty steps due to inaccurate timing, which can cause instability and accidents.
Innovation Solution
A data processing device that receives switching parameters to generate actuation signals for clutch actuators, controlling the timing and speed of switching movements to ensure simultaneous and accurate engagement of couplings during gear changes, thereby preventing intermediate and empty steps.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If two clutches are engaged simultaneously during gear change, then the gear change is completed, but intermediate gears may be engaged causing cadence disruption
Solution Approach 1:
The system performs preliminary actions by predicting future positions of both clutches based on current switching parameters before the gear change is executed. This allows the control device to determine optimal switching moments in advance, ensuring that both clutches will be engaged simultaneously without intermediate gear engagement. The prediction mechanism calculates future states and uses this information to plan the gear change sequence.
Solution Approach 2:
The system implements feedback by continuously monitoring actual switching parameters during the gear change process and comparing them with predicted values. The control device adjusts the switching moments of the clutches in real-time based on this feedback, ensuring simultaneous engagement. This closed-loop control eliminates intermediate gear engagement by dynamically correcting any deviations from the predicted switching sequence.
2Reliability
If clutch switching timing is not precisely controlled, then gear change may fail, but precise control requires complex timing coordination
Solution Approach 1:
The control device performs preliminary calculation of future clutch positions and determines optimal switching moments before execution. By predicting the state of both clutches in advance, the system simplifies the control task - instead of complex real-time coordination, the system uses pre-calculated switching moments that guarantee successful gear change. This predictive approach reduces control complexity while ensuring reliability.
Solution Approach 2:
The system uses the natural switching parameters and motion characteristics of the clutches themselves to determine the switching sequence. Rather than imposing an external complex control scheme, the control device leverages the inherent behavior of the clutch mechanism - predicting their future positions based on current parameters and using this self-generated information to control the switching moments. This self-service approach simplifies control while ensuring precise timing.
Data Source
Figure 1
Figure 2
Figure 3
AI summary
The invention relates to a data processing device (104) and a computer-implemented method for controlling a gear change in a bicycle transmission (4) for a bicycle (1) with or without an auxiliary motor (2), in particular a bottom bracket or hub gear, from one gear directly to another by automatically actuating a first and a second clutch actuator (42, 64). The invention further relates to a bicycle transmission with such a data processing device and a method for performing a gear change.The data processing device is configured to receive at least one switching parameter (112) that is representative of a state of the bicycle's gearbox; and, depending on the at least one switching parameter (112) and a gear-change signal (106) representing a command for a gear change, to output an actuation signal (120) for actuating the first and second clutch actuators (42, 64). The actuation signal (120) contains control data that is representative of a time interval between the actuation of the first clutch actuator (42) and the actuation of the second clutch actuator (64) and/or a set switching speed of the first clutch actuator (42) and a switching speed of the second clutch actuator (64). This configuration prevents free-pedaling or the unwanted engagement of an intermediate gear during gear changes.