An Internal Gear could be described as the contrary of an external gear in that one’s teeth point towards rather than away from the center, and planetary gearbox addendum and dedendum take invert positions. Internal Gears provide a compact parallel shaft transmitting drive with large speed reduction. Used with a standard spur pinion the ratio is equivalent to that of two exterior gears, however the center distance is a lot smaller. In cases where it is necessary to possess two parallel shafts rotate in the same direction, the inner gear eliminates the use of an idler gear.
Internal Gears possess a number of 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 external gear and pinion getting the same tooth ratio and tooth size. Which means relative slippage of the teeth is less in the case of the internal. This point presents among the benefits of using Internal Gears. The sliding action of 1 tooth over another causes friction; and because friction outcomes in tooth wear, a reduction in the amount of sliding action can be desirable.
Internal Gear drives could be operated with the apparatus in a fixed position and the pinion rotating along the pitch line, or the gear may be free to rotate with the pinion rotating in a fixed position.
When mating pinions are too close in size to the apparatus, interference may result. Therefore, the difference in tooth of the pinion to the gear should not be significantly less than 15.
RUSH GEARS inc. offers standard Internal Gears in STEEL, STAINLESS STEEL, CAST IRON, BRONZE, Aluminium, DELRIN and 
NON-METALLIC (PHENOLIC). We will gladly produce made to order Internal Gears to your requirements.