The Basics of Spiral Bevel Gears

derived from a straight rack with straight tooth profile. A particular gear, rolling in the rack with constant center dis-tance to the rack, requires involute flank surfaces. A shaping tool with the shape of a rack can machine a gear with a perfect involute flank form. Figure 1 shows a cylindrical gear rolling in a rack. To understand the bevel gear tooth geometry, one might first observe the case of straight bevel gears. If the generating rack used to derive the cylindrical gear involute is bent in a horizontal plane into a circular shape, it results in a crown gear, which is used to derive the flank form of bevel pinion and gear. In the case of straight bevel gears, the crown gear or generating gear can be placed between the pinion and gear assembly. Its center is located exactly at the intersec-This article also appear