June 18, 2006
June 18, 2006
June 21, 2006
11.189.1 - 11.189.10
An Innovative Approach to a Classic Design Project
Each year many gear reducers are designed by students of mechanical engineering and mechanical engineering technology in their machine design courses. In many instances, these design projects offer little challenge other than perhaps the volume of work that must be completed. This paper outlines a gear reducer design project that was created to be intentionally challenging. This was accomplished by requiring the gear reducer to have concentric shafts, double reduction, standard diametral pitches, and an exact train value that just might be a prime number. The project is structured around American Gear Manufacturers Association (AGMA) design procedures for spur gears, and is patterned after a line of commercially available gear reducers having a similar configuration and performance. The design specifications for the project, a methodology to satisfy the technical requirements, and a spreadsheet tailored to analyze the student’s gear designs are presented and discussed.
At the University of Dayton, junior mechanical engineering technology students are required to take a course in machine design titled Design of Mechanical Elements. The content is typical of many introductory courses in machine design with the content divided into three groupings. The first grouping contains topics that are a review and extension of those covered in an introductory strength of materials course. These topics typically include transverse shear stresses in beams, combined stress, symmetrical bending of beams in 2-planes, transformation of stress, principal stresses, and Mohr’s circle. The second grouping covers failure theories and fatigue. The third grouping contains topics from machine design like the design of shafts, spur gears, springs, fasteners, shear pins, keys, couplings, seals, roller bearings, and plain bearings. The text for the course is Machine Elements in Mechanical Design by Mott1. As an integrating capstone-type experience, the students are required to complete a design project.
The subject and scope of the project given in the Design of Machine Elements course varies somewhat depending on the instructor of the course. However, the project is typically the design of either a power transmission or a power transmission component. Either approach provides an excellent vehicle for the student to integrate many of the course topics into a single design project.
This paper focuses on a portion of a design project where the students are required to design a gear reducer. In this project the student must design two stages of spur gearing, the input, intermediate, and output shafts, select appropriate bearings and (where applicable) seals for each shaft, and configure the assembly. The project has now been successfully used three times and has been refined after each use. The current design specifications for the project include:
Penrod, J. (2006, June), An Innovative Approach To A Classic Design Project Paper presented at 2006 Annual Conference & Exposition, Chicago, Illinois. https://peer.asee.org/1335
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