Explanation And Design Of Internal Gear Systems

In engineering history, there are various kinds of gear systems are designed and used in various types of machinery and systems. One of them is internal gear systems.

Internal gear systems are the gear systems that in bigger gear includes teeth, inside of gear body. And pinion gear is placed inside the internal gear.

Why Internal Gears Are Used?

One of the most important reasons to use internal gears is the desire to obtain pinion and bigger gear is turning in the same direction. In regular gear pairs, turning rotations of pinion and bigger gear are not the same.

But idler gear systems are also used to obtain the same turning rotations in ordinary gear pairs.

The advantage of internal gear systems over idler gear addition is the saving from the place. When two external gears are assembled, the volume that is taken up is equal to the volumes of two external gears. But for internal gear pairs, the volume that is occupied is equal to just internal bigger gear.

Calculation Of Center Distance For Internal Gears

Center Distance Calculator For Internal Gears

You can use the calculator above the precisely calculate the center distance between internal gear pairs. You just need to enter the diametral pitch value of gears which is standard for gear pairs. If you have metric value for your gears, click on this link to convert it to diametral pitch value.

Enter the number of teeth of the internal gear and the pinion then click on the ‘Calculate!’ button to find out the center distance.


These are the general expression of the internal gears. Do not forget to leave your comments and questions about the internal gear and internal gear design below.

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