HENGIN's ring internal gear SIR series has an accuracy grade of JIS N9. Due to the thin thickness of the ring, it is difficult to produce high-precision products. On the other hand, gear manufacturers and grinding equipment that can improve the accuracy of internal gears by gear tooth grinding are limited, resulting in very high costs for grinding internal gears with high precision.In addition, the cost of helical internal gears is usually high. However, KHK has realized the simple production of helical internal gears using gear cutters by using gear cutting equipment that does not require a spiral guide.
Generally, the internal gear can be used with the same modulus spur gear. It must be noted that, depending on the combination of the number of teeth of the internal gear and spur gear, involute interference, trochoidal interference, and inter-gear interference may occur.