12:1 planetary reduction for servo or stepper output
The GBX0400120703F is a 40 mm-diameter planetary gearbox with a 12:1 reduction ratio — sized for the output shaft of a servo or stepper motor where you need to multiply torque and drop speed into the usable band for a linear actuator, conveyor roll, or indexing table. Continuous output torque is 20 N.m at 100 rpm, with a maximum peak of 32 N.m at the same speed — the 12:1 ratio means the input motor sees about one-twelfth the output torque reflected back, so a 2–3 N.m motor covers the continuous case. Straight-tooth spur gearing keeps the cost and backlash predictable — 28 arcmin maximum torsional backlash is typical for this class, adequate for positioning tasks that don't need zero-reversal precision.
Torque, life, and force limits at 100 rpm
All the load ratings — continuous torque, maximum torque, axial force, radial force, and service life — are specified at 100 rpm and 30 °C. At 20 N.m continuous the gearbox is rated for 30,000 hours; push it to 32 N.m peak and the life drops to the same 30,000-hour figure at the lower duty cycle implied by a peak rating. Axial force limit is 200 N for a 10,000-hour life, 160 N for 30,000 hours. Radial force applied at mid-shaft follows the same derating: 200 N for 10k hours, 160 N for 30k. These numbers govern bearing selection on the driven shaft — an overhung load from a belt or chain needs to stay under the radial limit or the gearbox life shortens. Efficiency is 94 % — the 6 % loss is mostly gear mesh friction and bearing drag. At 20 N.m and 100 rpm the input power is about 210 W; the 13 W loss heats the housing, which is black anodized aluminium for radiative cooling. Noise level is 55 dB at 1 m, no-load — this is the gear mesh whine without load-induced deflection. Under load the noise rises a few dB as the teeth deflect, but 55 dB is quiet enough for lab or light industrial environments.
Obsolete — sourcing through independent channels
Available through independent surplus and broker channels. Quantities are lot-specific and confirmed at RFQ. The gearbox is lubricated for life — no maintenance schedule, which simplifies storage and re-commissioning from surplus stock. Shaft output seal is IP54 — protects against dust ingress and splashing water, but not submersion. The housing is black anodized aluminium with a C 45 steel shaft. Operating ambient is -25 to 90 °C.