Bicycle Shifting Device Axial Coupling Release Mechanism
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing bicycle shifting devices face challenges in smoothly changing transmission ratios, especially under high load conditions, as they struggle to effectively transmit human power to adjust gear couplings efficiently.
Innovation Solution
The bicycle shifting device incorporates a first and second transmission unit, a coupling member, and a release unit, where the coupling member moves axially to couple and uncouple the second rotational body from the rotational shaft using human power, with a guide portion and restriction structure to stabilize movement and a biasing member to ensure stable coupling, allowing for improved shifting performance under high loads.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a wire and control ring are used to change the coupling state of pawls and shifting gears, then the device complexity is reduced, but the shifting performance deteriorates under high load conditions
Solution Approach 1:
The patent replaces the wire-based control system with a human power-based mechanical release unit. The release unit includes a release lever, release arm, and pawl mechanism that directly utilize human power to uncouple the second rotational body from the rotational shaft, eliminating the need for wire transmission and control rings while improving shifting performance under high load
Solution Approach 2:
The release unit is designed to utilize human power directly from the rider's pedaling action to operate the shifting mechanism. The human power transmitted through the first transmission unit activates the release mechanism, allowing the system to serve itself without requiring separate control wires or external actuation systems
2Reliability
If the coupling member is made movable in axial direction to enable uncoupling, then the shifting performance improves, but the device complexity increases
Solution Approach 1:
The coupling member is designed with dynamic characteristics, being movable in the axial direction to enable uncoupling of the second rotational body from the rotational shaft. This dynamic design allows the coupling member to transition between coupled and uncoupled states based on human power input, improving shifting performance while maintaining a relatively simple overall structure
Solution Approach 2:
The shifting device is segmented into distinct functional components: the first transmission unit, second transmission unit, coupling member, and release unit. This segmentation allows each component to perform its specific function independently, with the coupling member's axial movement providing the necessary uncoupling capability without complicating the entire system
3Stability of the object's composition
If a guide portion with restriction structure is added to stabilize coupling member movement, then the stability improves, but the device complexity increases
Solution Approach 1:
The guide portion acts as an intermediary element that stabilizes the movement of the coupling member. It includes a guide groove that restricts the coupling member's movement to the axial direction, ensuring stable and controlled uncoupling action without requiring complex constraint mechanisms
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
This configuration enhances shifting performance by increasing the force for uncoupling the second rotational body from the rotational shaft, thereby improving gear changes even under high load conditions, ensuring smoother and more efficient power transmission.
Implementation Method 1
a biasing member that biases the coupling member toward the second rotational body
Implementation Method 2
the guide portion has a restriction structure that restricts relative rotation of the rotational shaft and the coupling member
Implementation Method 3
the coupling member includes a cam surface that faces a side surface of the second rotational body, and the contact member contacts the cam surface to move the coupling member in the axial direction
Data Source
AI summary
A bicycle shifting device includes a first transmission unit, a second transmission unit, a coupling member and a release unit. The first transmission unit includes a first rotational body, to which human power is transmitted. The second transmission unit includes a second rotational body coupled to the first rotational body and a rotational shaft rotatably supporting the second rotational body. The coupling member is movable relative to the second rotational body in an axial direction of the rotational shaft and configured to couple the second rotational body and the rotational shaft so that the human power transmitted from the first transmission unit is transmitted to the rotational shaft through the second rotational body. The release unit uncouples the second rotational body from the rotational shaft by moving the coupling member in the axial direction using the human power transmitted from the first transmission unit.