# Structure and Characteristic of DC Gearbox Motor

Sometimes,when users choose DC motor, they would find that it cannot reach their requirement because of higher speed or lower torque, so gear motor solution is the best choice.

Dolin Gear motors micro DC gear motor uses standard DC motor. Diameter of gearbox is from 6 to 50mm,Voltage is from 1V to 30V; Low Speed: from 0.1rpm to 1500rpm

Torque: 0.1kg.cm to 400kg.cm;Low noise & Long lifetime expected;Power is under 50W.

How to Calculation of gear motor ?

1.Output Speed n= nm÷I (rpm).nm--DC motor speed;I--reduction ratio of gearbox

2.Torque T=Tm×i×ηg÷1000 (kg.cm);Tm--DC motor output torque,i--entire reduction ratio of gearbox;ηg--entire efficiency of gearbox (%)

3.Entire efficiency of gearbox ηg = η1×η2×η3×η4••• η1 – efficiency of the first pair of gear,η2--efficiency of the second pair of gear,η3--efficiency of the third pair of gear…the efficiency of every pair of gear is about 95%.

4.Input power P1=U×I (W) U:voltage (Voltage)，I:current (Amps)

5.Output power P2=T×n÷97.5 (W) T:torque (kg.cm)，n:speed (rpm)

6.Total efficiency of gear motor η=P2÷P1×100=ηm×ηg(%) ηm:efficiency of DC motor

The load torque of DC gear motor has direct relationship with speed and current. When the load increases,the speed linearly decreases and the current linearly increases.

So the gear motor has better working near maximum efficiency, then it can obtain ideal running performance, working life and stable characteristic.

In general,the working environment of DC gear motor is the same as DC motor. If there are any special requirement,such as environment temperature, overload, and current limit , reversible etc. need to advise us up front.

Expected working life of gearbox usually longer than DC motor, it can reach 1000 to 3000 hours.

The gearbox is combined with multi-pair of gears. Every step includes gear wheel and pinion which is joggled one another. The first pinion is mounted on the motor shaft of DC motor. The bearing of gearbox output shaft is usually oil bearing made of brass or iron.

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