Type of Gear Trains

What is gear train?

Gear train is a combination of gears and used for transmitting motion and power from one shaft to another shaft. Gear trains are used to achieve large and different velocity ratio in small area or space. Gear trains are use for increasing or reducing speed of driven shaft. Examples of gear trains use in machines are lathe machine, milling machine, in watch and many others. Different types of gear trains are as follow.

Simple gear train




Simple gear train is a type of gear train. Gear train are use to obtain different velocity ratio or to transmit power from one shaft to another. In simple gear train multiple gears are used to obtain different velocity ratio. Only one gear is mounted on each shaft and these shafts are rigidly fixed or not movable. Simple gear train consist three major area or part and these are driving gear, driven gear and intermediate gears. In which driving gear is mounted on driving shaft and driven gear is mounted on driven shaft and these both gears are mesh with the help of intermediate gears. In simple gear train intermediate gears play major role and intermediate gears will be one or more in simple gear train depending upon design or application. To obtain different velocity ratio different size gears are used. In simple gear trains power and motion transmit from driving gear to intermediate gears and from intermediate gears to driven gears. In this way simple gear trains are work.

Compound gear train




Compound gear train is a type of gear train in which two intermediate gears (gears between driving gear and driven gear) are mounted on one shaft. Means only one gear on driving shaft and driven shaft, and intermediate shafts have two mounted gears. Compound gear trains are use to get large velocity ratio or different speed in a small area or space. Compound gear box is good example of compound gear trains.



Reverted gear train




Reverted gear trains are a special type of gear trains. In which driving gear shaft axis and driven gear shaft axis are in a line. In reverted gear train one gear is mounted on each driving and driven shaft and on intermediate shaft two gears are mounted, reverted gear train are arrange in this way that driving gear transmit motion and power to intermediate shaft gear and other gear of intermediate shaft transmit motion and power to driven gear. Reverted gear trains are use there, where velocity ratio required in small space. Watches are good example of reverted gear trains. In watches reverted gear trains are used, in which minute and hour hands of watches are on a same axis.



Epicyclic gear train




In above gear trains simple gear train, compound gear train and reverted gear train, gear shaft axis is fixed or not movable but in epicyclic gear trains, the shaft axes are not fixed means the shaft axis is movable. There is a relative motion between the gears axis. Epicyclic gear trains may consist of simple gear trains, compound gear trains and mixed simple and compound gear trains. The advantage of epicyclic gear train is that, it can get very high or very low velocity ratio compared to simple gear trains and compound gear trains. The common example of epicyclic gear train is differential gear box of automobile

These are the type gear trains are use in machine according to require velocity ratio, speed, space and application.