... impressive.The geometry, design, and manufacture of helical gears was the subject of researchpresented in the works of Litvin et al. [ 19 95 , 19 99 , 2001a, 2003], Stosic [ 19 98 ], and Feng et al. [ 19 99 ].The ... (Figs. 14 .3.2 and 14 .3.3)φ, φ 1 , and φ2angle of gear rotation (Figs. 14 .4 .1 and 14 .5 .1) η2half of the angular tooth thickness on pitch circle of gear 2E shortest axes distance (Fig. 14 .5 .1) F (12 ,n)normal ... cylinder(i = b), and on the cylinder of radius ρ (Figs. 14 .2 .1, 14 .4.5 and 14 .4.7)µ 1 half of the angular width of the tooth space on the base circle of gear 1 (Fig. 14 .3.2)θ, θ 1 , and θ2surface...