5 Project Planning for Gear Units Overhung and axial loads 5.5Overhung and axial loads

Determining overhung loads An important factor for determining the resulting overhung load is the type of transmis-sion element mounted to the shaft end. The following transmission element factors f

have to be considered for various transmission elements. The overhung load exerted on the motor or gear shaft is calculated as follows:

Transmission element Transmission element factor f
Z CommentsGears 1.15< 17 teeth chain sprockets 1.40< 13 teeth chain sprockets 1.25< 20 teeth Narrow V-belt pulleys 1.75Influence of the tensile force Flat-belt pulleys 2.50Influence of the tensile force Toothed belt pulleys 1.50Influence of the tensile force

M2000d

••

F

d0 R

= f

Z

F

= Overhung load in NM

= Torque in Nmd

= Mean diameter of the installed transmission element in mmf Z

= Transmission element factor

Permitted over-hung load The basis for determining the permitted overhung loads is the computation of the ratedbearing service life L

10h

of the anti-friction bearings supplier (according to ISO 281).For special operating conditions, the permitted overhung loads can be determined withregard to the modified service life L

on request.The permitted overhung loads F

for the output shafts of foot-mounted gear units witha solid shaft are listed in the selection tables for gearmotors. Contact SEW-EURODRIVE in case of other versions. The values refer to force applied to the center of the shaft end (in right-angle gearunits as viewed onto drive end). The values for the force application angle Î± anddirection of rotation are based on the most unfavorable conditions. •Only 50% of the F

value specified in the selection tables is permitted in mountingposition M1 with wall attachment on the front face for K and S gear units.•Helical-bevel gearmotors K167 and K187 in mounting positions M1 to M4: A maxi-mum of 50% of the overhung load F

specified in the selection tables in the case ofgear unit mounting other than as shown in the mounting position sheets.•Foot and flange-mounted helical gearmotors (R..F): A maximum of 50% of the over-hung load F

specified in the selection tables for torque transmission via flangemounting are permitted.

46

Catalog – DR Gearmotors 01/2008