Many years ago, when asked how the
five-meter gear was checked, the quality manager responded, “When they’re that big, they’re never bad!” That may have been the attitude and practice in the past, but it no longer serves the manufacturer nor the customer. Requirements have been evolving steadily, requiring gears to
perform better and last longer.
Since we began publishing in 1984, Gear Technology's mission has been to educate our readers. For 31 years, we've shown you the basics of gear manufacturing as well as the cutting edge. We take our educational mission quite seriously, and we go through steps that most publishers don't have time for or wouldn't consider.
This paper presents the geometric design of hypoid gears with involute gear teeth. An
overview of face cutting techniques prevalent in hypoid gear fabrication is presented. Next,
the specification of a planar involute rack is reviewed. This rack is used to define a variable
diameter cutter based upon a system of cylindroidal coordinates; thus, a cursory presentation
of cylindroidal coordinates is included. A mapping transforms the planar involute rack into a variable diameter cutter using the cylindroidal coordinates. Hypoid gears are based on the envelope of this cutter. A hypoid gear set is presented based on an automotive rear axle.
At the dawn of the Industrial
Revolution, so-called mechanics
were tasked with devising the precise methods that would make mass production possible. The result was the first generation of machine tools, which in turn required improved tooling and production methods.