Question

For a pair of spur gears with a diametral pitch of 12, and a 20° degree pressure angle and with the number of teeth on the pinion 11 and the number of teeth on the gear 18, compute all the features of the gear teeth described below: (a) Pitch diameter for the gear, (b) Pitch diameter for the pinion (c) The circular pitch, (d) Addendum, (e) Dedendum, (f) Clearance, (g) Whole depth, (h) The tooth thickness (hint: based on circular pitch), (i) Center-to-center distance (j) radius of the base circle for the gear and radius of the base circle for the pinion.

Answer 1

GEAR (Spur Gear) Bottom land face width Tip. Telank? Tooth thickness Root Clearance -Circle Addendum Circle Dedundum Coucle -Pitch Girele. Toosh Space - Tooth, thickness = Backlash ? Tooth thickness. Tooth space addendum Dedendum d Clearance с face width b Circular Pitch Pe Diametral Pitch Pd m = 1.157 m 0.157 m 10 m m. 1 m & Pd = m = mo dule D Pitch Cinde Diameter Z Number of Teeth Circular Pitch Pe E Am - TD Z Tooth thickness + Tooth Space = fa Top za Tooth thickness = Tooth Space = Pc 2 d = 360 angle covered by thickness space on centre 22

Diametral pitch No. of of Teeth Pitch circle Diameter for Gear, 12 = 18 D DE 1.5 for Pinion, 52 = 11 d d = 0.9167 Circular Pitch - * 1.5 AD T 18 Pc = 0.2618 Module m = 0.083 1.5 18 Addendum = a = m = 0.083 Dedundum : 1.157 m 0.096 Clearance = C = 0.157 m = 0.013 whole depth Addendum + dedundum 0.179 Tooth Thicknes = Tooth Space - Pc 2 0.1309 d Centre to Centro distance D 2 + 2 = 1.20835 Radius of Base circle db=rcoso i for Gear Rb 15 1.5 cos 20° Rb 0.7040 9- press wre angle r- pitch circle radius for Pinion de=0.9167 cos 20° 2 = 0.4307