Cylindrical gears with straight external teeth

rechte stub-vertanding

Module = mn = Image7 or Image8 or Image126
Normal pitch in mm = pn = mn or Image10
Normal base pitch in mm = pbn = pn.cosa
Number of teeth = z = Image127 or Image128 or Image129
Pitch diameter = d = z.mn or Image130 of da – 2.mn or Image131
Tip diameter in mm = da = mn.(z + 2) or 2.mn + d or d + Image14
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 or 1,16. Image15 (a = 14°30’)
= hf = 1,25.mn or 1,25. Image15 (a = 20°)
Rim thicknes below the tooth in mm = H = approx 1,6.mn minimum
Centre distance in mm = a = Image132

NOTES:

  • Most teeth have a pressure angle of 20° and a dedendum of 1.25. mn, so the total height is then 2.25. mn.
  • For certain special teeth a fully rounded dedendum is requested; in this case the tip-root clearance is between 0,375.mn till 0,4.mn. For these teeth there are naturally special tools required.