An Internal Gear may be described as the contrary of an external gear in that one’s teeth point towards instead of away from the guts, and addendum and dedendum consider reverse positions. Internal Gears provide a compact parallel shaft tranny drive with large rate reduction. Used with a typical spur pinion the ratio is the same as that of two external gears, however the center distance is a lot smaller. Where it is necessary to have two parallel shafts rotate in the same direction, the internal gear eliminates the use of an idler gear.
Internal Gears possess several advantages when properly used. One such benefit is reduced sliding action. The corresponding working surfaces of 
one’s teeth of an internal gear and pinion are more nearly of the same size than may be the case with an external gear and pinion having the same tooth ratio and tooth duration. Which means relative slippage of the teeth is less planetary gearbox regarding the internal. This aspect presents one of the benefits of using Internal Gears. The sliding action of 1 tooth over another causes friction; and as friction outcomes in tooth wear, a reduction in the amount of sliding action is usually desirable.
Internal Gear drives could be operated with the gear in a set position and the pinion rotating along the pitch line, or the gear may be absolve to rotate with the pinion rotating in a set position.
When mating pinions are as well close in proportions to the gear, interference may result. As a result, the difference in tooth of the pinion to the apparatus should not be significantly less than 15.
RUSH GEARS inc. offers standard Internal Gears in Metal, STAINLESS, CAST IRON, BRONZE, Aluminium, DELRIN and nonmetallic (PHENOLIC). We will gladly produce made to order Internal Gears to meet your needs.