Machine design lab: Using automotive transmission examples to reinforce understanding of gear train analysis

Abstract

In studying mechanical gear train analysis, some students struggle with relatively simple gear design concepts, and virtually all have difficulty with the complexities of planetary gear sets. This paper describes two labs developed for an undergraduate senior level machine design course. One lab uses a three-speed manual synchromesh transmission with parts of the case cut away to demonstrate the operation of the gears, shifting mechanism, bearings, and other aspects of the design. Students then count teeth and analyze the gear ratios using standard gear train analysis methods. The other lab uses a 1924 Ford Model T planetary transmission to observe how planetary gears can create two forward speeds and reverse from constant rotation of the engine. The students analyze the planetary gear set using relative velocity analysis, and the planetary gear set is used to gain insight into basic principles of modern automatic transmissions. The two labs give students hands-on learning experience that clarifies difficult concepts and teaches students basic principles of gear train design, operation, and analysis. © 2011 American Society for Engineering Education.