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Unformatted text preview: g ley 7 ed. or Bud ynas 8 ed] can help to det ermine gear parameters. o Face widt h (FW) o f spur gear is reco mmended t o be w it hin [9m, 14m], m is mo du le. o Face widt h (FW) o f helical gear is reco mmend ed to be at least t wice o f t he axial p it ch px to o bt ain good helicalgear action. The transverse circular pitch, pt, normal circular pitch, pn, and axial pitch px, are related as: p x = p / tan , p n = p cosy , cosy = tan f n / tan ft , where ft and fn are pressure y t t angles in rotation and transverse direct ions and y is helix angle of teeth. o Face widt h (FW) o f bevel gear is reco mmend ed to be e it her 0.3A0 o r 10m depends which is smaller. o Wo r m gear ing toot h fo rms are NOT hig hly st andard ized: pressure ang les depend o n lead ang les and must be large enough to avoid undercutting of the worm gear tooth on the side where contact ends. o Face widt h o f worm gear sho u ld be equal t o lengt h o f a t angent to wo rm p it ch circle between it s points of intersection with addendum circle. GEAR TRAINS o Relatio nships between a dr iving p inio n and a driven gear n P N G , where, n , nG are ration speed of pinio n and gear, in rpm; N P , N G are tooth numbers of = P n N...
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- Fall '09