June 14, 2015
June 14, 2015
June 17, 2015
26.1101.1 - 26.1101.10
Machine Design Experiments Using Gears to Foster Discovery LearningFor the typical undergraduate engineering student the topic of gears is introduced and discussedin several courses. Early exposure may be in a physics course or in a first dynamics course,where gear pairs are presented as an idealized means to change speed ratios and torque ratios.They are used for mechanical advantage or to achieve desired speed, and the focus is usually onkinematics. Since gears have inertia they store kinetic energy and are part of the dynamicequations of motion of mechanisms and machines. For mechanical engineering students, gearsare a core component studied in courses such as 'kinematics and dynamics of mechanisms' and'machine design', where the nomenclature and design equations are developed for various typesof gears. There may be exposure to real gears in a mechanical engineering laboratory; moreoften, students may see gears passed around in class and as part of demonstrations.In this paper we describe new experiments that were designed to provide mechanical engineeringstudents with discovery learning experiences with gears and mechanical systems using gears.The suite of practical experiments presents students with a range of challenges that require themto analyze, measure, design, and fabricate gears. Activities in the experiments include: (1) Identifying gear types (spur, helical, bevel, etc.) and appropriate applications (automotive transmissions and differentials, drills, gearhead motors). (2) Disassembling and re-assembling a kitchen mixer (with design and manufacturing questions related to its gears). (3) Disassembling and re-assembling an automotive HVAC baffle subassembly (with measurement of train ratios, and design and manufacturing questions related to its gears). (4) Designing the gear mechanism for driving the minute and hour hands of a gear clock given a known yet arbitrary drive speed. Fabricating the gears of the clock via rapid prototyping (3D printing), assembling the clock, and then testing the timing accuracy.In addition to reporting the details of the experiments, we share experiences of students andteaching assistants in their use and effectiveness. We provide insights into how well studentsbecame familiar with types and nomenclature of gears and understood the applicability ofdifferent gears to actual real-world problems. The intent of the experiments is to effectivelyenhance mechanical engineering students' awareness of gears and expand their knowledge andconfidence in the use of gears in machine and mechanism design.
Slightam, J. E., & Nagurka, M. L. (2015, June), Machine Design Experiments Using Gears to Foster Discovery Learning Paper presented at 2015 ASEE Annual Conference & Exposition, Seattle, Washington. 10.18260/p.24438
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