Test run is provided as reference for calculation algorithm. Listing is taken from pg program.
Analysis of Planetary Transmissions
INPUT DATA:
Kinematics:
Input -> Sun
Fixed -> Ring
Output -> Carrier
Number of teeth of the Sun gear: 21
Number of the Planets : 3
Number of teeth of the Ring gear: 108
Geometry:
Normal modul: 1.75 mm
Helix angle: 0 deg
Normal angle: 20.0 deg
Addendum of basic rack: 1.00 of module
Bottom clearance: 0.25 of module
Face width: 38.00 mm
Gear quality: 6
RESULTS
Number of teeth of the Planet gears: 43
Transmission ratio: 6.14286
Center distance (a): 56.8 mm
Widths (b):
Sun 39.75 mm
Planet 38.00 mm
Ring 41.50 mm
Addendum modification coefficients (x):
Sun 0.4380 of module
Planet 0.0426 of module
Ring 0.0000 of module
Reference diameter (d):
Sun 36.7500 mm
Planet 75.2500 mm
Ring -189.0000 mm
Tip diameter (da):
Sun 41.7008 mm
Planet 78.8170 mm
Ring -185.4992 mm
Number of teeth in a span (k):
Sun 3
Planet 5
Base tangent length for "k" teeth (Wk):
Sun 13.9546 mm
Planet 24.3530 mm
Diameter of measuring sphere (Dm): 3.0000 mm
Dimension over balls (Mdk): -184.7755 mm
Profile form error : 5 um
Radial run-out (Fr):
Sun 11 um
Planet 12 um
Ring 14 um
Total aligment error (Fb): 9 µm