Cylindrical gears

Cilindrische schroefwielen

Normal module = mn = Image7 = mt.cosb = Image135 .cosb
Transverse module = mt = Image136
Normal pitch in mm = pn = pt.cosb = mn.p
Transverse module in mm = pt = Image137
Normal base pitch in mm = pbn = pn.cosan = pt. cosan.cosb
Transverse pitch in mm = pbt = pt. cosat
Number of teeth = z =Image138 or Image139or Image140
Virtual number of teeth = zv = Image141
Pitch diameter in mm = d = z.mt of Image142 or Image143
Tip diameter in mm = da = d+2.mn
Facewidth in mm = b = 10.mn
Tooth depth in mm = h = 2,16.mn or 2,16.Image15 for a= 14°30’
= h =2,25.mn or 2,25.Image15 for a= 20°
Addendum in mm = ha = mn or Image15
Dedendum in mm = hf = 1,16.mn (1,25.mn)
Thickness below the tooth in mm = H = approx 1,6.mn minimum
Centre distance in mm = a = Image144
Helix angle = cosb = Image145 = Image146 = Image147
Base helix angle = tgb b = tgb .cosa t
Transverse pressure angle = tga t = Image148

NOTES:

Cylindrical gears are used in transmissions between parallel or crossed shafts. For the crossed shafts the case of having an angle different from 90° are omitted; after all this hardly occurs. The abovementioned formulas apply on cylindrical gears for parallel and / or crossed shafts; for the size and direction of the tooth angles there are, however, separate rules we will explain below.