1. Using the simplified approach (do not refine results by using AGMA equations), design a single-reduction straight spur gear unit to operate from a 5.0-hp electric motor running at 900 rpm to drive a rotating machine operating at 80 rpm. The motor is to operate steadily at full rated power. Near-infinite life is desired. A reliability of 90 percent is acceptable for this application. It is proposed to use ASTM A-48 (class 40) gray castiron material for both gears. Using , properties for this material may be based on Chapter 3 data, except for surface fatigue strength, which may be taken as psi. A safety factor of 1.3 is desired. As part of the design procedure, select or determine the following so as to satisfy design specifications:
a. Tooth system .
b. Quality level.
c. Diametral pitch.
d. Pitch diameters.
e. Center distance .
f. Face width .
g. Number of teeth on each gear. Do not attempt to evaluate heat generation.
