Course No. 71
Gears and Gearing – Helical Gears
Identification of helical gears, their dimensions and measurement procedures; helix angle, shaft angle, and the relationship between them; how to determine the “hand” of helical gears; diametrical pitch (DP), pitch diameter (PD), pressure angle and the use of formulas for DP and PD; selection of a desired helical gear from a stock gear catalog; differences between helical gears on parallel and right angle shafts; direction of rotation of helical gears on parallel shafts and on right angle shafts and how to determine direction of one gear if direction of the other is known on right angle shafts; idler helical gears; thrust of helical gears and how to determine direction of the thrust on parallel and right angle shafts; double helical (or herringbone) gears and how they are different from straight helical gears; and a review of major differences between helical and spur gears.
Prerequisites: Ability to perform simple arithmetic calculations and to read simple engineering drawings. A basic understanding of spur gears, gear ratios and gear installation.
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