Planetary Speed Increaser for Compact Bicycle Transmission Load Relief
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Solution Overview
Problem
Existing components for human-powered vehicles do not efficiently transmit human driving force, leading to increased loads on the transmission device and potential size constraints.
Innovation Solution
A component comprising a transmission device, a shaft member, and a speed increaser with at least one planetary gear group, which reduces torque input to the transmission device, thereby decreasing loads and allowing for a more efficient transmission of human driving force.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the transmission device directly receives human driving force without a speed increaser, then the structure is simpler, but the torque input to the transmission device is higher, increasing loads on the transmission device
Solution Approach 1:
A speed increaser mechanism is introduced as an intermediary component between the human driving force input and the transmission device. This mediator increases rotational speed and reduces torque before the force reaches the transmission device, thereby decreasing the load on the transmission device while maintaining overall system functionality.
2Length of moving object
If the input rotational shaft is positioned close to the transmission device, then the component size in the axial direction is smaller, but the human driving force cannot be efficiently transmitted to the transmission device
Solution Approach 1:
The speed increaser mechanism is designed to rotate about the rotational center axis of the shaft member, utilizing the radial dimension rather than extending axially. This dimensional arrangement allows efficient force transmission through the speed increaser while keeping the axial length of the component compact, effectively decoupling the transmission efficiency from axial size constraints.
3Length of moving object
If the speed increaser is designed with planetary gear groups rotating about the shaft member's rotational center axis, then the axial size is reduced, but the gear arrangement becomes more complex
Solution Approach 1:
The planetary gear groups are arranged concentrically around the rotational center axis of the shaft member, with gears nested within each other in radial layers. This nesting arrangement allows multiple gear stages to be compacted into a small axial space while maintaining clear functional separation and manageable complexity through systematic configuration.
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
The component effectively transmits human driving force with reduced loads on the transmission device, allowing for a preferred manner of force transmission while also decreasing the component's size in the axial direction.
Implementation Method 1
The speed increaser includes at least one first planetary gear group. The at least one first planetary gear group is rotatable about a rotational center axis of the shaft member.
Data Source
AI summary
A component for a human-powered vehicle basically includes a transmission device, a shaft member and a speed increaser. The transmission device includes a plurality of transmission stages. The shaft member is spaced from an input rotational shaft of the human-powered vehicle and arranged on the shaft member. The speed increaser is configured to transmit a human driving force that is input to the input rotational shaft to the transmission device. The speed increaser includes at least one first planetary gear group. The at least one first planetary gear group is rotatable about a rotational center axis of the shaft member.