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Project Planning for Gear Units RM gear units 5.6RM gear units

Project planning You must take account of the higher overhung loads and axial forces when planningprojects with RM helical gearmotors with extended bearing housing. Observe the follow-ing project planning procedure:

Start of ProjectPlanning a = Conversion factor from data tableb = Conversion factor from data tablec
Determine the requirements of theapplication F = Gear-unit constants from data tableF = Axial loads during operationF • Performance• Torque• Output speed• Overhung load (F
a F = Gear-unit constants from data tableF
R = Overhung loadsduring operationF
R )/ axial load (F
a )• Lever arm (x-dimension)
Ra = Permitted overhung load (at x = 1000 mm) from data tableF
XF = Permitted overhung load on the housing (flange tensile strength)F
Select minimum service factors,e.g.: XL = Permitted overhung load according tobearing service lifex = Distance between force application and shaft shoulder •• ff
Bmin = 1.5 for L
10h 10 000 h
Bmin = 2.0 for L
10h 25 000 h M = Output torqueF = Permitted axial load
aAa all other requirements on request Select gear-unit size based onminimum service factor: f
Bmin f
B(gearunit) Select next largergear unit Check overhung load (bearing /shaft)? no F R F XL = F Ra •a/(x+b) yes x-dimension
R F
XF = c
F /(F
F +x)
Select next largergear unit yes F no no R Check axial load?
no (F • x/F )
yes F /M > 3 F
R Aa aa a F
Aa yes yes Special solutionon request from SEW Check connection dimensions Determine additional features required: • gear unit with double seal• dry-well-version (special feature)• leakage sensor (special feature)• relubrication of bearings (special feature) Additional featuresnecessary?
yes no End ofPoject Planning 02457BEN

Figure 7: Project planning for RM gear units

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Catalog – DR Gearmotors 01/2008