Planetary gearbox for precision indexing and positioning
The GBX0400200551F is a 40 mm diameter planetary gearbox from Schneider Electric's GBX series, delivering a 20:1 reduction ratio with straight-cut teeth. It's sized for servo-driven positioning axes where repeatable indexing matters more than peak torque. Continuous output torque is 20 N.m at 100 rpm, with a maximum intermittent torque of 32 N.m at the same speed — the margin covers acceleration peaks in pick-and-place cycles or indexing tables.
Torque, life, and the real duty cycle
Rated service life is 30,000 hours at 100 rpm and 30 °C ambient, which translates to roughly 3.4 years of continuous 24/7 operation at that speed. The gearbox is lubricated for life, so no maintenance interval for oil changes — just monitor the input-side bearing temperature. Efficiency is 94 % at rated load, typical for a single-stage planetary with straight teeth. The 6 % loss is mostly gear mesh friction and bearing drag; it shows up as heat in the housing, so the black anodized aluminium body acts as the heatsink. Maximum torsional backlash is 28 arcmin — that is the total angular play between input and output when reversing direction. For a 20:1 ratio, 28 arcmin at the output corresponds to about 1.4 arcmin at the input side; acceptable for general positioning, but not for high-precision contouring where you would spec a lower-backlash version. Torsional rigidity is 1.1 N.m/arcmin — the stiffness of the gear train under load. At the continuous torque of 20 N.m, the wind-up is roughly 18 arcmin from the gear train alone, before the backlash gap closes. This matters when the load oscillates or when you need positional hold under varying torque.
Mounting and environmental fit
Mounts in any position — horizontal, vertical shaft-up, or vertical shaft-down — with no derating for orientation. The IP54 rating on the shaft output means it resists dust ingress and splashing water at the seal; the rest of the housing is sealed by the anodized surface and O-rings at the joints. The C 45 steel output shaft handles radial and axial loads: 200 N radial (applied at mid-shaft) and 200 N axial for a 10,000-hour life at 30 °C, derated to 160 N for the full 30,000-hour rating. Noise level is 55 dB at 1 m, no-load — quieter than a typical office printer. In a machine with servo drives and cooling fans, the gearbox noise will be masked by the ambient floor level.