Spur Gear Selection - Cross & Morse

1 Tel +44 121 360 0155 Fax +44 121 325 1079 Email For a required centre distance and gear ratio a suitable pair of spurgears can be selected used and assessed by the following numbers of teeth in gears and module (pitch). gear Ratio i = Shaft centre distance in mm = sum gear teeth xpitch= (Z1+ Z2) PFrom this initial Selection each gear can be assessed for strength andwear using the following formulae. The least of the four calculatedpowers is the capacity of the gear set. The capacity required isdetermined by multiplying actual power by a service factor relativeto driver and driven equipment, refer page 3.

2 If calculated power isbelow required capacity increase pitch or face width of gears, adjustteeth sizes accordingly, and reassess drive. If calculated power issubstantially in excess of required capacity a lower Module couldbe considered. Strength capacity Ps= XbxSbxYSxF xN xZ xP2kw19,100 x103 Wear capacity Pw = Xc x Scx YZx Fx Nx Zx ,000 x103 Where:- F = Face width mmN = gear shaft speed = gear pitch, Module Bending stress for gear material (see below)Sc = Surface stress for gear material (see below)Xb= Speed factor for strength - see table 1Xc= Speed factor for wear - see table 2YS= Strength factor - see table 3YZ= Zone factor - see table 4Z= Number of teethSpur gear Selection9 Factors Sb and Sc GearsGear TypeSb N/mm2Sc N/mm2 Steel Gears and racksCast (Teeth driven gear )Z1(Teeth driven gear )

3 1/21/2 Table 2 Combined Speeed Factor for Wear Xc (for 26000 hour rating)Daily Shaft 1 Speed factor for Strength Xb (for 26000 hour rating)Daily Shaft 3 Strength Factor Ys No. TeethRackNumber Teeth Mating of Teeth on gear being 4 Zone Factor Yz(Note: factor same for both gears in gearset) No. TeethRackNumber Teeth Mating Gear121314151617181920222426283035405060 7080100127 RackNumber of Teeth on gear being +44 121 360 0155 Fax +44 121 325 1079 Email Standard spur Mod spur Gears Suffix of Cat.

4 No. indicates gear type gear Type A gear Type B BDdpdABDdpdCDimensions tables for spur Gears and gears machined from medium carbon, induction hardening steels. Pitch1 Mod1 Mod25301517 ABGear Mod spur GearsCat. TeethPitch Dia. dpMin Bore dMax. BoreHub COutside Dia. DWeight TeethPitch Dia. dpMin Bore dMax. BoreHub COutside Dia. DWeight TeethPitch Dia. dpMin Bore dMax. BoreHub COutside Dia. DWeight TeethPitch Dia. dpMin Bore dMax. BoreHub COutside Dia.

5 DWeight +44 121 360 0155 Fax +44 121 325 1079 Email Standard spur GearsBDdpdABDdpdCDimensions tables for spur Gears to gears machined from medium carbon steels. Pitch2 Mod3 Mod4 Mod5 Mod6 ModABGear Widths mm354050607580202530405060 gear Type A gear Type B Mod spur Gears Suffix of Cat. No. indicates gear Mod spur GearsCat. TeethPitch Dia. dpMin Bore dMax. BoreHub COutside Dia. DWeight TeethPitch Dia.

6 DpMin Bore dMax. BoreHub COutside Dia. DWeight TeethPitch Dia. dpMin Bore dMax. BoreHub COutside Dia. DWeight TeethPitch Dia. dpMin Bore dMax. BoreHub COutside Dia. DWeight +44 121 360 0155 Fax +44 121 325 1079 Email Mod spur GearsStandard spur Mod spur Mod spur Mod spur GearsCat. TeethPitch Dia. dpMin Bore dMax. BoreHub COutside Dia. DWeight TeethPitch Dia. dpMin Bore dMax. BoreHub COutside Dia. DWeight TeethPitch Dia.

7 DpMin Bore dMax. BoreHub COutside Dia. DWeight TeethPitch Dia. dpMin Bore dMax. BoreHub COutside Dia. DWeight kgS4038A381522590 TeethPitch Dia. dpMin Bore dMax. BoreHub COutside Dia. DWeight TeethPitch Dia. dpMin Bore dMax. BoreHub COutside Dia. DWeight kgS5038A3819030110 TeethPitch Dia. dpMin Bore dMax. BoreHub COutside Dia. DWeight TeethPitch Dia. dpMin Bore dMax. BoreHub COutside Dia. DWeight