Nested Intermediate Shaft Gearbox for More Ratios in Less Length
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Solution Overview
Problem
Conventional dual-clutch gearboxes face challenges in increasing the number of gear ratios to improve performance, driveability, and emissions, which results in increased size, making it difficult to accommodate in vehicles, especially mid- and rear-engine vehicles where it affects handling.
Innovation Solution
A gearbox design featuring a first main clutch, a second main clutch, input shafts, intermediate shafts, lay shafts, and coupling mechanisms that allow for a plurality of gear ratios, with the output shaft coupled to the wheels via a differential, and the lay shafts positioned to reduce the overall length by eliminating the need for reverse gears, enabling the gearbox to be more compact.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the number of gear ratios is increased to improve performance and driveability, then the gear ratios provide better performance, driveability, and emissions, but the overall length of the gearbox increases making it difficult to accommodate in vehicles
Solution Approach 1:
The patent implements a nested intermediate shaft arrangement where an inner intermediate shaft is positioned within an outer intermediate shaft. Both shafts carry drive gears and are coupled to the input shaft via clutches, allowing multiple gear ratios to be achieved within a compact radial space. This nesting configuration enables increased gear ratio capacity without proportionally increasing the gearbox length.
2Adaptability or versatility
If more drive gears and shaft gears are added to increase gear ratios, then more gear ratios are achieved, but the width of the vehicle needs to be increased in transverse engine vehicles
Solution Approach 1:
The patent transitions from a conventional single-intermediate-shaft layout to a multi-layer nested intermediate shaft configuration. By utilizing the radial dimension (placing the inner intermediate shaft within the outer intermediate shaft), the design achieves multiple gear ratios without increasing the axial length or radial width of the gearbox, thereby maintaining compact vehicle packaging.
3Adaptability or versatility
If the gearbox length is increased to accommodate more gear ratios, then more gear ratios are provided, but the overall length of mid- and rear-engine vehicles increases which is not desirable for performance
Solution Approach 1:
The nested intermediate shaft configuration allows the gearbox to achieve multiple gear ratios within a compact axial footprint. By stacking gear sets radially rather than extending them axially, the design reduces the overall gearbox length, which directly translates to shorter vehicle length for mid- and rear-engine configurations, preserving handling and performance characteristics.
Data Source
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AI summary
A gearbox comprising: an outer intermediate shaft carrying a first set of shaft gears; an inner intermediate shaft carrying a second set of shaft gears, the inner intermediate shaft running concentrically within the outer intermediate shaft;a first lay shaft carrying a first set of drive gears and an output gear positioned along the first lay shaft between two of the first set of drive gears, a second lay shaft carrying a second set of drive gears and an output gear positioned along the second lay shaft between two of the second set of drive gears, each drive gear being coupled to a respective shaft gear to together provide a plurality of gear ratios between the intermediate shafts and the output shaft; and an output shaft, each lay shaft being coupled to the output shaft by the respective output gear.