Chapter 11, Problem 18P

For the shaft application defined in Prob. 3-77, p. 153, the input shaft EG is driven at a constant speed of 191 rev/min. Obtain a Basic Load Rating for a ball bearing at A for a life of 12 kh with a 95 percent reliability, assuming distribution data from manufacturer 2 in Table 11-6.

3-77* A torque T = 100 N · m is applied to the shaft EFG, which is running at constant speed and contains gear F. Gear F transmits torque to shaft ABCD through gear C, which drives the chain sprocket at B, transmitting a force P as shown. Sprocket B, gear C, and gear F have pitch diameters of a = 150, b = 250, and c = 125 mm, respectively. The contact force between the gears is transmitted through the pressure angle ϕ = 20°. Assuming no frictional losses and considering the bearings at A, D, E, and G to be simple supports, locate the point on shaft ABCD that contains the maximum tensile bending and maximum torsional shear stresses. Combine these stresses and determine the maximum principal normal and shear stresses in the shaft.