Bicycle Gear Shift Control With Coordinated Front-Rear Derailleurs
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Solution Overview
Problem
Traditional bicycle transmission systems with separate control devices for front and rear derailleurs can be cumbersome, requiring complex adjustments to achieve desired gear changes, especially when large transmission ratio changes are needed.
Innovation Solution
A bicycle transmission control system with a first and second transmission, each with actuatable derailleurs, controlled by a controller that simplifies gear shifts through intuitive sensing devices and actuators, allowing seamless transitions between multiple discrete and continuous transmission ratios.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If separate control devices are used for front and rear derailleurs, then each transmission can be controlled independently, but the operation becomes cumbersome and complex adjustments are required for desired gear changes
Solution Approach 1:
The patent combines control of both front and rear derailleurs into a single integrated control device with multiple sensing devices. This allows the cyclist to operate both transmissions through one interface, eliminating the need to manage separate control devices and their respective cables independently, thus simplifying the overall operation while maintaining independent transmission control capability
Solution Approach 2:
The single control device is designed with multiple sensing devices that can control different transmissions (front derailleur, rear derailleur, internal hub transmission) depending on the selected mode. This multi-functional design allows one control device to perform the work of multiple separate control devices, improving ease of operation without sacrificing adaptability
2Speed
If front derailleur is used for large transmission ratio changes, then quick gear range switching is achieved, but complex compensation shifts are needed in the rear derailleur
Solution Approach 1:
The controller receives signals from multiple sensing devices and monitors the current transmission state. When a gear shift is commanded, the controller calculates the appropriate coordination between front and rear derailleurs based on feedback about current gear position, ensuring that large ratio changes from the front derailleur are properly compensated by rear derailleur adjustments without requiring complex manual coordination from the cyclist
Solution Approach 2:
The electronic controller acts as an intermediary between the sensing devices and the derailleur actuators. It processes the shift command, determines the optimal coordination strategy between front and rear transmissions, and automatically executes the coordinated shifts, eliminating the need for the cyclist to manually manage the complexity of multi-transmission coordination
3Measurement precision
If multiple separate control devices are provided for different transmissions, then each transmission can be precisely controlled, but the overall system complexity increases
Solution Approach 1:
Multiple sensing devices that would traditionally be part of separate control devices are merged into a single integrated control unit. This consolidation maintains the precision control capability for each transmission while reducing the overall number of separate control devices and their associated cable routing, thus lowering system complexity
Solution Approach 2:
The electronic controller serves as an intermediary that receives precise control signals from multiple sensing devices and translates them into coordinated actuation commands for multiple derailleurs. This electronic mediation replaces complex mechanical cable linkages and enables precise control of multiple transmissions through a unified control interface, reducing structural complexity while maintaining control precision
Data Source
AI summary
A bicycle transmission control system for controlling a bicycle transmission, comprising a first control device comprising at least a first and a second sensing device, the first sensing device being actuatable through a first user contact surface, and the second sensing device being actuatable through a second user contact surface different from the first user contact surface, a second control device comprising at least a third and fourth sensing device, the third sensing device being actuatable through a third user contact surface. and the fourth sensing device being actuatable through a fourth user contact surface different from the third user contact surface: and a controller that is operatively connected to the sensing devices of the first and second control devices, wherein the controller is configured to control the bicycle transmission to activate a gear shift upon actuation of one of the first, second, third or fourth sensing devices.