CAD Model - Automatic Transmission based on Allison 1000 System
Unlike the manual transmission in which a specific gear ratio has to be selected, the automatic transmission system adjusts the gear ratio by itself as per the torque requirements. They are classified as:
Planetary gearbox Direct shift gearbox CVT – Continuously variable transmissionThis project shows the design of an automatic gearbox based on the Allison 1000 system. The working is based on a simple idea, we have three elements here. The sun gear, the planet carrier and the outer ring. By holding one of the element motionless a gear ratio can be produced from the other two. A total of six gear ratios can thus be produced. Typically two of them are under drive and two are overdrive. Some gear ratios produced are on the extremes and aren’t usually used. Usually three gear ratios are taken from each planetary set.
This design includes three planetary sets. This particular drive produces a 5 speed transmission. The complex clutch mechanism has not been included in this project.
This project was done as a part of the curriculum for a design oriented project during my undergraduate Mechanical degree at BITS,Pilani.
GrabCAD link: https://grabcad.com/library/automatic-transmission-allison-1000-based-1
A Solidworks render of the model with the planetary sets
One of the components of the transmission which rotates as a single component but acts as a Ring, Planet and the Sun Gear for the all the three planetary gear sets in the transmission system
Exploded view of the whole assembly
A Solidworks render of the model with the planetary sets