Small gear motors integrate the motor and gearhead in a single housing, which is different from a motor-gearhead combination where the two components are considered separate products and are combined depending on their application.
The motor of a small gear motor can be designed either brushless (brushless small gear motor) or brushed (DC small gear motor). The gearhead itself is usually a planetary or spur gear design. Small gear motors are primarily used when compact drives with a low speed are required.
When configuring the gear motors for the target applications, it must be taken into account that the output shaft is sometimes offset to the motor's rotary axis. Other important parameters of a small gear motor are the ratio, the overall efficiency, the backlash, the maximum torque at the output, the maximum speed, and the maximum axial and radial shaft load.
Modern applications primarily use motor-gear combinations, as this allows for significantly greater design flexibility due to the many more options available.