Each gear has a tangential force applied at the pitch radius by a mating gear. The bearing...

Each gear has a tangential force applied at the pitch radius by a mating gear. The bearings are located near each gear so that the loads on the shaft are primarily torsional. The number of teeth on a gear is proportional to the pitch radius of the gear. Neglect losses in the systems.

An 18-kW motor operates at 3600 rpm (Figure P6.10). Gears A and B each transmit 5 kW from the shall, whereas gear C transmits 8 kW. The shaft is made of ductile steel with a shear yield strength τY = 180 MPa. The design safety factor of the shaft is SF = 1.80 for general yielding. Determine the minimum required diameter of the shaft.

FIGURE P6.10