Wheel Hub Stepping Clutch for Low-Force Internal Gear Shifting
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Solution Overview
Problem
Existing internal speed change devices for bicycles require large structures and high operating forces due to direct lever control, leading to increased weight, power consumption, and cost, as well as reduced lever lifespan.
Innovation Solution
A control device for indirect clutching operation in wheel hubs, featuring a sun gear, guiding trenches, shaft or teethed claws, and a stepping clutch mechanism driven by a rotating unit, allowing for stepwise rotation and non-direct lever operation to control the fixedness of the sun gear, reducing resistance and effort required.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a lever directly controls the opening and closing of a control claw to retain or un-retain a sun gear, then the clutching operation can be achieved, but the lever requires large moving distance and high operating force, resulting in larger structure and reduced lever lifespan
Solution Approach 1:
A control rod is introduced as an intermediary component between the lever and the control claw. The lever controls the control rod, which in turn controls the control claw. This indirect control mechanism reduces the operating force required on the lever and eliminates the need for the lever to have large moving distance, while maintaining the clutching function.
Solution Approach 2:
The direct control function is segmented into multiple components: the lever, the control rod, and the control claw. By dividing the control function across these separate components, each can be optimized for its specific function, reducing the overall structural complexity and improving ease of operation.
2Reliability
If a lever directly controls the sun gear retaining mechanism, then clutching operation is achieved, but the lever receives high resistance directly from the sun gear, decreasing lever lifespan
Solution Approach 1:
The control rod serves as a mediator that transmits the control force from the lever to the control claw without subjecting the lever to high resistance from the sun gear. This protects the lever from excessive forces and extends its service life.
3Weight of moving object
If direct lever control is used for sun gear clutching, then the structure can be simple, but the lever requires large moving distance and high force, increasing overall system weight and power consumption
Solution Approach 1:
The control rod intermediary allows the lever to operate with smaller moving distance and lower force, reducing the mechanical advantages needed and thereby reducing overall system weight while maintaining ease of operation.
Data Source
AI summary
A control device of an internal speed change device of a wheel hub for indirect clutching operation includes a sun gear installed on a sun gear ring which is installed on a wheel shaft; a shaft claw installed between the sun gear and the wheel shaft; a stepping clutch mechanism installed on the wheel shaft; the stepping clutch mechanism being driven by a rotating unit; the stepping clutch mechanism serving to control opening and closing of the shaft claw to control fixedness of the sun gear; the stepping clutch mechanism including a plurality of first control claws and a plurality of second control claws for controlling clutching operation between the stepping clutch mechanism and the rotating unit; and a lever installed in one of at least one guiding trench of the wheel shaft.