Effects of using cutter with asymmetric tip radius on root stress of thin and solid rimmed internal gear

Nowadays internal spur gears are used in many industrial areas because of their numerous advantages such as reduced sliding velocity and wear, higher transmission ratio, higher running efficiency. In contrast of the external gear an internal gear is generated by pinion cutters towards inside of gear blank. In this study, bending stress of internal spur gear generated with the cutter that has asymmetric tip radius was investigated. This condition is let to use larger tip radius on one side. Firstly, a mathematical equation of pinion cutter is derived and then the points of internal gear are obtained by using coordinate transformation, differential geometry and gearing theory in MATLAB. For realizing the 2D design the points of internal gears are exported to CATIA program. Then for determining the relation between tip radius and bending stress, the case studies are conducted respectively with ANSYS program. According to preliminary results, using asymmetric trochoid concept is rather advantageous when comparing symmetric one.