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@bharrisau
Last active April 8, 2019 02:15
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A selection of compact split compound planetary gears

Conducted a search of gear configuations matching the below requirements:

  • Minimum module of 1mm
  • Maximum outer diameter of 55mm (ring dedenum plus a 1mm wall)
  • All meshing gears co-prime
  • Module values must be terminating decimals
  • Planetary gears must be similar size (planet addendums equal, ring dedendums equal, or somewhere between)
  • At least 11 teeth on all gears (minimise undercut)
  • Minimum of 4 planets (6 planet options indicated)

Found 7 gear configurations, 6 of which permit driving via sun gear in addition to planet carrier. (>=12 tooth options highlighted)

  • 30x reduction, 52.1mm diameter, 16t/1.05m planet with 45t ring, 11t/1.45m planet with 32t ring
  • 49x reduction, 52.3mm diameter, 13t/1.08m planet with 44t ring, 11t/1.24m planet with 38t ring (6 planets supported)
  • 58x reduction, 50.2mm diameter, 13t/1.25m planet with 36t ring, 11t/1.4375m planet with 31t ring
  • 60x reduction, 49.4mm diameter, 13t/1.04m planet with 43t ring, 11t/1.2m planet with 37t ring
  • 77x reduction, 52.1mm diameter, 15t/1.15m planet with 41t ring, 13t/1.3m planet with 36t ring
  • 91x reduction, 49.0mm diameter, 12t/1.08m planet with 41t ring, 11t/1.16m planet with 38t ring (6 planets supported)
  • 100x reduction, 52.5mm diameter, 17t/1.04m planet with 46t ring, 15t/1.16m planet with 41t ring
  • 134x reduction, 52.1mm diameter, 16t/1.05m planet with 13t sun and 45t ring, 11t/1.45m planet with 32t ring
  • 170x reduction, 52.3mm diameter, 13t/1.08m planet with 18t sun and 44t ring, 11t/1.24m planet with 38t ring (6 planets supported)
  • 212x reduction, 49.4mm diameter, 13t/1.04m planet with 17t sun and 43t ring, 11t/1.2m planet with 37t ring
  • 311x reduction, 49.0mm diameter, 12t/1.08m planet with 17t sun and 41t ring, 11t/1.16m planet with 38t ring (6 planets supported)
  • 365x reduction, 52.1mm diameter, 15t/1.15m planet with 11t sun and 41t ring, 13t/1.3m planet with 36t ring
  • 481x reduction, 52.5mm diameter, 17t/1.04m planet with 12t sun and 46t ring, 15t/1.16m planet with 41t ring

Additional options allowing 60mm diameter and minumum 12 teeth: (>=13 tooth options highlighted)

  • 44x reduction, 57.9mm diameter, 17t/1.15m planet with 46t ring, 13t/1.45m planet with 36t ring
  • 56x reduction, 57.7mm diameter, 19t/1.04m planet with 51t ring, 15t/1.28m planet with 41t ring
  • 57x reduction, 59.5mm diameter, 14t/1.16m planet with 47t ring, 12t/1.32m planet with 41t ring (6 planets supported)
  • 63x reduction, 57.7mm diameter, 17t/1.08m planet with 49t ring, 14t/1.28m planet with 41t ring
  • 75x reduction, 59.3mm diameter, 16t/1.03125m planet with 53t ring, 14t/1.15625m planet with 47t ring (6 planets supported)
  • 107x reduction, 56.0mm diameter, 13t/1.16m planet with 44t ring, 12t/1.24m planet with 41t ring (6 planets supported)
  • 199x reduction, 59.5mm diameter, 14t/1.16m planet with 19t sun and 47t ring, 12t/1.32m planet with 41t ring (6 planets supported)
  • 211x reduction, 57.9mm diameter, 17t/1.15m planet with 12t sun and 46t ring, 13t/1.45m planet with 36t ring
  • 265x reduction, 59.3mm diameter, 16t/1.03125m planet with 21t sun and 53t ring, 14t/1.15625m planet with 47t ring (6 planets supported)
  • 270x reduction, 57.7mm diameter, 17t/1.08m planet with 15t sun and 49t ring, 14t/1.28m planet with 41t ring
  • 274x reduction, 57.7mm diameter, 19t/1.04m planet with 13t sun and 51t ring, 15t/1.28m planet with 41t ring
  • 367x reduction, 56.0mm diameter, 13t/1.16m planet with 18t sun and 44t ring, 12t/1.24m planet with 41t ring (6 planets supported)

18 gear combinations are >=12 teeth and <=55mm if scaling the design so the smallest module == 1 is done. The other module will be an imprecise module value. (>=13 teeth highlighted)

  • 31x reduction, 52.6mm diameter, 17t/1.15m planet with 48t ring, 12t/1.55m planet with 35t ring
  • 41x reduction, 53.6mm diameter, 19t/1.15m planet with 49t ring, 14t/1.5m planet with 37t ring
  • 44x reduction, 50.6mm diameter, 17t/1.15m planet with 46t ring, 13t/1.45m planet with 36t ring
  • 57x reduction, 51.5mm diameter, 14t/1.16m planet with 47t ring, 12t/1.32m planet with 41t ring (6 planets supported)
  • 63x reduction, 53.6mm diameter, 17t/1.08m planet with 49t ring, 14t/1.28m planet with 41t ring
  • 77x reduction, 45.6mm diameter, 15t/1.15m planet with 41t ring, 13t/1.3m planet with 36t ring
  • 81x reduction, 53.6mm diameter, 15t/1.2m planet with 49t ring, 13t/1.36m planet with 43t ring
  • 100x reduction, 50.6mm diameter, 17t/1.04m planet with 46t ring, 15t/1.16m planet with 41t ring
  • 107x reduction, 48.5mm diameter, 13t/1.16m planet with 44t ring, 12t/1.24m planet with 41t ring (6 planets supported)
  • 123x reduction, 51.5mm diameter, 14t/1.24m planet with 47t ring, 13t/1.32m planet with 44t ring (6 planets supported)
  • 139x reduction, 52.6mm diameter, 17t/1.15m planet with 14t sun and 48t ring, 12t/1.55m planet with 35t ring
  • 199x reduction, 51.5mm diameter, 14t/1.16m planet with 19t sun and 47t ring, 12t/1.32m planet with 41t ring (6 planets supported)
  • 211x reduction, 50.6mm diameter, 17t/1.15m planet with 12t sun and 46t ring, 13t/1.45m planet with 36t ring
  • 270x reduction, 53.6mm diameter, 17t/1.08m planet with 15t sun and 49t ring, 14t/1.28m planet with 41t ring
  • 289x reduction, 53.6mm diameter, 15t/1.2m planet with 19t sun and 49t ring, 13t/1.36m planet with 43t ring
  • 367x reduction, 48.5mm diameter, 13t/1.16m planet with 18t sun and 44t ring, 12t/1.24m planet with 41t ring (6 planets supported)
  • 428x reduction, 51.5mm diameter, 14t/1.24m planet with 19t sun and 47t ring, 13t/1.32m planet with 44t ring (6 planets supported)
  • 481x reduction, 50.6mm diameter, 17t/1.04m planet with 12t sun and 46t ring, 15t/1.16m planet with 41t ring
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