Offset Chamfered Gear Teeth for Smooth Shifting
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Solution Overview
Problem
Existing power train components in all-terrain vehicles and motorcycles face issues with binding and difficulty in smoothly shifting gears due to axial movement against spring bias, particularly when moving between multiple gear positions, leading to uncontrolled engagement forces.
Innovation Solution
The implementation of coaxially arranged gears with offset chamfer edges on the teeth surfaces, facilitating smoother movement between engaged and non-engaged positions by reducing initial misalignment and binding, allowing for easier gear shifting.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If the driving gear is axially biased by a spring toward one direction to control shifting force, then the shifting force is regulated and determined by spring constant, but the gear binding occurs during axial movement against spring force and smooth shifting becomes difficult
Solution Approach 1:
The chamfered tooth surfaces are pre-formed on the driving and driven gears before engagement. These chamfers create preliminary contact surfaces that guide the axial movement and reduce misalignment before the main tooth engagement occurs, preventing binding during the shifting process against spring force
Solution Approach 2:
The chamfered surfaces act as intermediary contact surfaces between the driving gear and driven gear teeth. Instead of the full tooth width engaging directly, the chamfers provide a gradual transition zone that mediates the engagement process, reducing shock and binding during axial movement
2Volume of moving object
If the driving gear moves between three axial positions to engage with multiple driven gears, then the gearbox size is reduced, but the axial movement force becomes uncontrolled and binding occurs in at least one direction
Solution Approach 1:
Different chamfer configurations are applied to different sides of the driving gear teeth. One side has chamfers optimized for engagement with the first driven gear, while the other side has chamfers optimized for engagement with the second driven gear. This local differentiation allows controlled axial movement in both directions without binding, enabling compact multi-gear design
3Power
If the gear teeth are engaged with high number of teeth in contact, then torque transfer is improved, but the initial misalignment and binding during engagement becomes more significant
Solution Approach 1:
The chamfered surfaces perform preliminary alignment and contact before the full tooth width engages. This preliminary action ensures that even when many teeth are engaged simultaneously, they all make contact smoothly without significant misalignment or binding, maintaining both high torque transfer and smooth engagement
Data Source
AI summary
A power train component such as a gearbox includes driving and driven, coaxially arranged cooperating gears which engage each other via teeth. The engaging end surfaces of the teeth are provided with a first chamfer and a second chamfer, in which the chamfer edge is offset from bisecting the tooth. Preferably the offset chamfer edges are provided on both a driving gear (shifter), axially positionable using a shifting fork on a shift drum, and a driven low gear. In one preferred driving gear (shifter) design, the offset chamfer edges are only provided for the side engaged when the shifting fork moves against a spring force. The invention facilitates smoother and less binding movement between the non-engaged and the engaged axial positions, such that the gear can be more easily shifted by the shifting fork in at least one direction.