Bicycle Shifting Controller with Dynamic Delay for Chain Engagement
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Bicycle shifting systems face challenges in coordinating the front and rear shifting devices to prevent simultaneous changes, which can lead to disengagement of coupling members like chains or belts, and existing systems lack flexibility in adjusting delay times based on gear ratios and rotational speeds.
Innovation Solution
A bicycle shifting apparatus with a controller that adjusts the delay time period for shifting operations based on gear ratios, rear shift positions, and current rotational speeds, using stored reference time periods and shift-map information to coordinate front and rear shifting devices, ensuring synchronized shifting while preventing simultaneous changes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the front shifting device and rear shifting device change shift positions simultaneously, then the shifting operation is fast and responsive, but the coupling member (chain or belt) may disengage from the shifting devices
Solution Approach 1:
The controller introduces a delay time period for the rear shifting device relative to the front shifting device. This preliminary timing adjustment ensures that shifting operations are sequenced rather than simultaneous, preventing coupling member disengagement while maintaining responsive shifting performance.
2Device complexity
If a fixed delay time period is used for rear shifting device operation, then the control logic is simple, but the system cannot adapt to different gear ratios and rotational speeds
Solution Approach 1:
The delay time period is made dynamic rather than fixed. The controller adjusts the delay time based on detected gear ratios and rotational speeds, allowing the system to adapt to different operating conditions. This dynamic adjustment maintains reliability across various scenarios while the controller manages the increased complexity through automated sensing and calculation.
Solution Approach 2:
The delay time period parameter is changed based on gear ratio and rotational speed conditions. The controller selects appropriate delay times from stored reference values corresponding to different gear ratios and speed ranges, enabling the system to optimize shifting behavior for each operating condition.
3Reliability
If the delay time period is extended to prevent disengagement, then coupling member engagement reliability is improved, but shifting response time increases and efficiency decreases
Solution Approach 1:
The delay time period is optimized based on gear ratio and rotational speed parameters. For higher gear ratios and speeds where disengagement risk is greater, longer delay times are applied. For lower ratios and speeds, shorter delays suffice. This parameter-based optimization maintains reliability while minimizing unnecessary delays that would reduce shifting efficiency.
Data Source
AI summary
A bicycle shifting apparatus comprises a shifting controller. The shifting controller is configured to control one of a front shifting device and a rear shifting device to change one of a front shift position and a rear shift position in response to a user input. The shifting controller is configured to control the other of the front shifting device and the rear shifting device to change the other of the front shift position and the rear shift position with a delay time period in conjunction with the one of the front shifting device and the rear shifting device in response to the user input. The shifting controller is configured to change the delay time period based on at least one of a gear ratio, the rear shift position, and a current rotational speed of a bicycle crank.