4:1 reduction, 15 N.m continuous — the real load envelope
The GBX0400040403D is a 40 mm-diameter planetary gearbox with a 4:1 reduction ratio, straight-cut teeth, and a black anodized aluminium housing. It delivers 15 N.m continuous output torque and can handle 24 N.m peak — the continuous figure is the one to size against for a servo axis that runs cycles all shift. Efficiency is 96 %, so about 4 % of the input power dissipates as heat inside the housing. At 15 N.m output and 100 rpm that is roughly 6 W of thermal loss — well within the aluminium housing's natural convection capacity at 30 °C ambient.
Backlash and torsional windup — positioning error budget
Maximum torsional backlash is 30 arcmin — that is the lost motion at the output shaft when the input reverses direction. For a pick-and-place axis with a 10:1 effective ratio after the belt, 30 arcmin at the gearbox translates to roughly 0.5 mm of positioning uncertainty at the load; budget it into the controller's backlash compensation or accept it as a deadband. Torsional rigidity is 1 N.m/arcmin — the shaft winds up 1 arcmin for every N.m of applied torque. At the 15 N.m continuous rating the windup is 15 arcmin, which adds to the backlash figure for the total angular error under load.
30,000-hour service life — bearing and gear fatigue limits
Rated service life is 30,000 hours at 100 rpm output speed and 30 °C ambient. At that operating point the maximum radial force on the output shaft is 160 N (applied mid-shaft), and the maximum axial force is 160 N. Run it at higher speed or temperature and the life derates — the 10,000-hour figures allow 200 N radial and 200 N axial. The gearbox is lubricated for life — no oil changes or regreasing intervals. Shaft output seal is IP54, so it keeps out dust and light splash but is not rated for washdown.
Mounting and integration — any position, 40 mm bore
Mounts in any position — horizontal, vertical, or inverted — with no oil migration concern because the lubrication is a lifetime grease charge. The 40 mm outer diameter and C 45 steel output shaft suit direct coupling to a servo motor with a matching pilot diameter. Noise at no-load is 55 dB at 1 m — about the level of a quiet office printer, so it will not dominate the acoustic profile of a machine cell.