Automatic Bicycle Hub Transmission With Sequential Centrifugal Shifting
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Solution Overview
Problem
The existing automatic internal transmissions in bicycles often experience 'overshifting' during gear shifting, which affects the cycling experience by skipping intermediate gears, leading to an inconsistent and less efficient power transmission.
Innovation Solution
The proposed automatic internal transmission incorporates a hub shaft with an input and output mechanism, featuring a transmission mechanism with a first and second planetary gear train, and an automatic shift control mechanism using a centrifugal block and clutch control unit. The centrifugal block rotates to different states to control the clutch control unit, ensuring smooth gear shifting without skipping intermediate gears by synchronizing the rotation of the clutch control unit along the same direction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Extent of automation
If multiple independent centrifugal blocks and clutch control units are used for controlling different gears, then gear shifting automation is achieved, but overshifting occurs causing intermediate gears to be skipped
Solution Approach 1:
The patent combines multiple independent centrifugal blocks into a single integrated centrifugal block structure that controls multiple clutch control units simultaneously. This unified structure ensures that when the centrifugal block is thrown out by centrifugal force, it sequentially engages the clutch control units in a controlled manner, preventing overshifting while maintaining automation. The merging of previously independent components into a coordinated system resolves the contradiction between automation and shifting accuracy.
2Ease of operation
If a centrifugal block is thrown out to control clutch rotation for gear shifting, then automatic gear change is achieved, but intermediate gears may be skipped affecting cycling experience
Solution Approach 1:
The patent designs the centrifugal block with pre-positioned control surfaces and engagement features that prepare the system for sequential gear engagement. Before the centrifugal block is fully thrown out, the structure is already configured to engage clutch control units in the correct sequence, ensuring intermediate gears are properly engaged. This preliminary configuration prevents overshifting and maintains power transmission efficiency while preserving the ease of automatic operation.
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 solution effectively prevents 'overshifting' by ensuring that intermediate gears are engaged during transitions, providing a smoother and more efficient cycling experience by maintaining proper power transmission through synchronized gear shifting.
Implementation Method 1
When the rotation speed of the hub reaches a certain extent, the centrifugal block is 'thrown out' outwards due to the action of a centrifugal force
Data Source
AI summary
An automatic internal transmission and a bicycle are provided. The automatic internal transmission includes a hub shaft, an input mechanism, an output mechanism, a transmission mechanism having a first planetary gear train and a second planetary gear train, and an automatic shifting control mechanism having a clutch control unit and a centrifugal block being connected to the output mechanism and the clutch control unit. The centrifugal block can rotate relative to the output mechanism to a first state in a first direction, to drive the clutch control unit to rotate, so that a driving force is transmitted via the first planetary gear train. The centrifugal block can further rotate relative to the output mechanism to a second state in the first direction, to drive the clutch control unit to further rotate, so that the driving force is transmitted via the second planetary gear train.