Gearbox Selector Barrel Layout for Reduced Axial Length
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Solution Overview
Problem
The need to locate selector forks between adjacent gear ratios in traditional gearbox assemblies limits the overall minimum axial length, making them less compact, especially when high-speed accuracy and clearance are required.
Innovation Solution
A gearbox assembly with a selector barrel located inside the second shaft and a selector shoe assembly that connects a selector peg to a rotating selector ring, eliminating the need for space between adjacent gears for selector forks, allowing for a more compact design by using a selector shoe assembly to set the axial position of the selector ring.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If selector forks are used to move selector rings between adjacent gear ratios, then the gear selection function is achieved, but the axial length of the gearbox increases
Solution Approach 1:
The selector barrel is positioned inside the second shaft (main shaft), creating a nested configuration where the selector mechanism components are housed within the existing shaft structure. This eliminates the need for external selector forks and reduces the overall axial length of the gearbox while maintaining the gear selection function.
Solution Approach 2:
The invention transitions from a linear external fork mechanism to a rotational barrel mechanism with radial tracks. The selector peg moves along radial tracks in the selector barrel, converting the motion dimension from axial (external forks) to radial (internal barrel), thereby reducing axial length requirements.
2Measurement precision
If selector forks are made sturdy to move at high speeds accurately, then high-speed accuracy is achieved, but the clearance and axial space requirements increase
Solution Approach 1:
By nesting the selector barrel inside the main shaft, the mechanism achieves compact dimensions while maintaining structural integrity. The radial track configuration provides inherent guidance and support, enabling accurate high-speed operation without requiring excessive clearance or axial space.
Solution Approach 2:
The radial track design in the selector barrel provides guidance in a different dimension compared to external forks. This radial configuration naturally constrains the selector peg motion, achieving high-speed accuracy without requiring the same axial clearance that external forks would need.
Data Source
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AI summary
A gearbox assembly comprises a first shaft and a second shaft, a gearset comprising a first gear wheel fixed to the first shaft and a second gear wheel that is supported by an annular bearing assembly around the second shaft, the second gear wheel having an engagement face, in which the first gear wheel and second gear wheel are permanently intermeshed to define one gear ratio of the gearbox so that rotation of the first shaft causes corresponding rotation of the first gear wheel and in turn rotation of the second gear wheel. A selector mechanism comprises a selector barrel located inside the second shaft having at least one selector barrel track that guides a selector peg, rotation of the selector barrel causing movement of the selector pin in a direction that is parallel to the axis of the second shaft, and a selector ring assembly is movable axially along the second shaft between an engaged position and a disengaged position, the selector ring in the engaged position engaging with the second gear wheel and in the disengaged position being spaced apart from the second gear wheel. The assembly further comprises a selector shoe assembly that connects the selector ring assembly to the selector peg so that the axial position of the selector ring is set by the axial position along the second shaft of the selector peg.