Micro DC motors can be equipped with planetary gearboxes and spur gear reducers. Most reducers have plastic or metal input gears, which can reduce noise during high-speed operation. Metal gears are used in high torque scenarios.

When choosing a gearbox, it is important to remember that changes in the gearbox position not only affect the output speed and torque level on the output shaft, but also have a greater impact.

1、 Bounce

Tooth clearance is a characteristic of the gearbox and gear system structure, allowing for bi-directional shaft clearance. This may be caused by excessive tolerances in gear design, time-varying tooth wear, and slight machining errors during gear cutting. It is measured on the output shaft of the gearbox and typically varies between 1 and 7 degrees. The back gap depends on the load and will increase with the increase of the load. Gaps can cause significant errors in the positioning system and should be compensated for. Usually, the shaft encoder is installed on the micro motor shaft instead of the output gear shaft of a small DC gear reducer micro motor. This means that the armature position of the micro motor can differ from the expected position of the output gear shaft by the backlash of the gear. A 3 ° angle on the output shaft of the gearbox may indicate hundreds of encoder pulses on the micro motor, depending on the resolution of the encoder and the ratio of the gearbox. For example, if a 512 pulse shaft encoder is used and the transmission ratio of the gearbox is 43:1, a 3 ° backlash on the gearbox output shaft may mean that the system generates a maximum of 183 encoder errors.

By applying load tension on the shaft before starting movement, clearance can be eliminated in one direction. For more dynamic bidirectional applications, gaps can be compensated electronically by comparing external absolute encoders with shaft encoders. It is possible to program motion control electronic devices to correct positional errors

The zero backlash reducer mechanically eliminates backlash. They are dual channel spur gear reducers, with each channel pre tightened to eliminate shaft clearance.

2、 Bearing selection

Ball bearings are commonly used in applications with high radial and axial shaft loads. In some cases, using ball bearings can increase audible noise. Please refer to the gearbox data sheet for axle load specifications. Sintered bearings can be used for applications with lower torque, characterized by lower radial shaft load and constant load characteristics. Ceramic bearings are alternative products for cost sensitive applications, where extending service life and improving radial load-bearing capacity are crucial.

Extra caution should be taken when pressing the components into the output shaft of the gearbox. We recommend not to exceed the rated compression force specified in the gearbox data sheet. This will damage the bearings and internal gears themselves. In some cases, the gearbox shaft bearings (only ball bearings) are pre installed with small waveform washers below the fixed rings of the bearings. Exceeding the compression force specifications on the data sheet will damage the waveform washer and counteract the preload on the bearing. This will affect the performance of the bearings and should always be avoided.

3、 Lubrication

The lubrication of gears and bearings may be the decisive factor in the performance of the gearbox. The bearing system and gear system of the gearbox are lubricated for life. No need for further lubrication, it is not recommended to do so. The use of unapproved lubricants on or around gearboxes or micro motors may have a negative impact on their functionality and expected lifespan.

The standard lubricant for reduction gears is formulated to provide the best service life with minimal current consumption under no-load conditions. Specially lubricated gear systems can also be used for extended temperature and vacuum environments.

4、 Input speed and rotation direction

The input speed specifications on the precision gearbox data sheet refer to the recommended input speed for maximizing the lifespan of the gearbox. It can be considered as the average safety value of the operation. The application may not require the maximum service life of the gearbox, and according to performance requirements, it can safely exceed this input speed specification. All gearboxes are reversible. In the micro motor data table, you may see an equal or unequal symbol. Don't let this confuse you. This simply means that when a positive voltage is applied to the positive terminal of the micro motor and a negative voltage is applied to the positive terminal of the micro motor, the output shaft of the reducer is proportional to or not equal to the direction of rotation of the micro motor.

5、 Locked rotor and reverse drive

Usually, we do not recommend blocking the gearbox when the micro motor is powered on. Due to the wide speed ratio range of the gearbox, even in low current situations, the micro motor has sufficient power. If the gearbox is blocked or stalled, it can "overload" the gearbox. This means that the torque generated on the micro motor is sufficient to peel off the gears and even cut off the output shaft in the rear stage of the reducer. If it is necessary to block the gearbox to stop it, careful consideration should be given to setting appropriate current limits in the application.

It is not recommended to drive the gearbox in reverse. Reverse drive refers to applying a torque to the output shaft of the gearbox, which in turn drives the input stage of the gearbox. This can damage the gearbox in various ways, including causing it to get stuck or simply breaking the output shaft.