Design the shaft for 72 teeth gear if the shearing stress is not to exceed 60 MPa in the shaft.

Question

A simple gear train consists of three gears with 18, 16 and 72 teeth. The 18 teeth pinion is connected to a 4 kW electric motor running at 2400 rpm. Design the shaft for 72 teeth gear if the shearing stress is not to exceed 60 MPa in the shaft.