18-3 For the case study problem, use helical gears anddesign the intermediate shaft. Compare your
results with the spur gear design presented in thischapter.
Case Study Problem Specification:
Section 1–18, p. 34, presents the background for this case studyinvolving a speed reducer. A two-stage, compound reverted geartrain such as shown in Fig. 18–1 will be designed. In this chapter,the design of the intermediate shaft and its components ispresented, taking into account the other shafts as necessary.
A subset of the pertinent design specifications that will beneeded for this part of the design are given here.
-Power to be delivered: 20 hp
-Input speed: 1750 rpm
-Output speed: 82–88 rev/min
-Usually low shock levels, occasional moderate shock Input andoutput shafts extend 4 in outside gearbox
-Maximum gearbox size: 14-in x 14-in base, 22-in height
-Output shaft and input shaft in-line
-Gear and bearing life > 12 000 hours; infinite shaft life
