Automatic Transmission Reverse Idler Elimination
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Solution Overview
Problem
Existing automatic transmissions of the twin clutch type face challenges in achieving downsizing and lightweighting due to the need for dedicated reverse idler gears, which complicate power transfer routes and increase dimensions.
Innovation Solution
The design eliminates the reverse idler gear by using a single output gear that meshes with both forward and reverse speed drive gears, allowing for a unified power transfer route and simplifying the sequence of power transfer between reverse and forward speeds, thereby enabling a more compact and lightweight transmission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a dedicated reverse idler gear is provided for meshing with the reverse drive gear, then the reverse speed function is achieved, but the transmission dimensions increase and weight increases
Solution Approach 1:
The output gear is designed to serve dual functions: it acts as the output gear for forward speeds and as the meshing partner for the reverse drive gear during reverse operation. This multi-functionality eliminates the need for a dedicated reverse idler gear, reducing transmission volume while maintaining reverse speed functionality.
Solution Approach 2:
The patent merges the function of the reverse idler gear with the output gear itself. By making the output gear directly mesh with both the reverse drive gear and the first speed driven gear, the separate reverse idler gear component is eliminated, consolidating functions into a single gear structure.
2Reliability
If a dedicated reverse idler gear is provided, then the reverse speed function is achieved, but the transmission weight increases
Solution Approach 1:
The output gear is designed to serve dual functions: it acts as the output gear for forward speeds and as the meshing partner for the reverse drive gear during reverse operation. This multi-functionality eliminates the need for a dedicated reverse idler gear, reducing transmission weight while maintaining reverse speed functionality.
Solution Approach 2:
The patent merges the function of the reverse idler gear with the output gear itself. By making the output gear directly mesh with both the reverse drive gear and the first speed driven gear, the separate reverse idler gear component is eliminated, consolidating functions into a single gear structure and reducing overall weight.
3Reliability
If separate power transfer routes are used for reverse and forward speeds, then the reverse function is achieved, but the sequence of power transfer becomes complex
Solution Approach 1:
The patent merges the power transfer routes by having the output gear directly engage with both the reverse drive gear and the first speed driven gear. This creates a unified power transfer path where the same output gear handles both reverse and forward speed operations, simplifying the sequence of power transfer while maintaining distinct functional routes through gear engagement selection.
Data Source
AI summary
A power transmission 1 includes an output shaft 9 disposed in parallel to an input shaft 5, and provided at one end with an output gear 35 and at an opposite end with a final drive gear 36 meshing with a final driven gear 37 of a differential device 10, the output gear 35 normally meshing with a reverse speed drive gear 26, and with a first speed driven gear 31 in an array 39 of driven gears 31, 32, 33, and 34 on a counter shaft 8 normally meshing with a first speed drive gear 14 in an array 20A of odd-speed shift position drive gears 14, 15, 16, and 17 on an odd-speed shift position drive shaft 6.