An Internal Gear could be described as the contrary of an external equipment in that one’s teeth point towards instead of away from the center, and addendum and dedendum consider invert positions. Internal Gears give a small parallel shaft transmitting drive with large rate reduction. Used with a typical spur pinion the ratio is the same as that of two external gears, however the planetary gearbox 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 utilization of an idler gear.
Internal Gears possess several advantages when properly used. One such advantage is reduced sliding actions. The corresponding working areas of one’s teeth of an internal gear and pinion are more nearly of the same size than is the case with an exterior 
gear and pinion getting the same tooth ratio and tooth duration. Which means relative slippage of the teeth is less in the case of the internal. This aspect presents one of the advantages of using Internal Gears. The sliding action of 1 tooth over another causes friction; and as friction results in tooth wear, a reduction in the quantity of sliding action is usually desirable.
Internal Gear drives could be operated with the apparatus in a fixed position and the pinion rotating along the pitch line, or the apparatus may be free to rotate with the pinion rotating in a fixed position.
When mating pinions are too close in proportions to the gear, interference may result. Consequently, the difference in teeth of the pinion to the apparatus should not be significantly less than 15.
RUSH GEARS inc. provides standard Internal Gears in Metal, STAINLESS, CAST IRON, BRONZE, Aluminium, DELRIN and nonmetallic (PHENOLIC). We will gladly manufacture made to order Internal Gears to meet your needs.
