How to choose the appropriate motor for planetary gearbox

How to choose the appropriate motor for planetary gearbox

When adapting to micro motors, planetary reducers must consider parameters such as the type of driving motor, output power, diameter specifications, operating voltage, lifespan, noise environment, no-load output speed, and installation method.

1) The type of motor.
The common driving motors for planetary gear motors include brush motors, brushless motors, hollow cup motors, stepper motors, and other micro motors as the driving source. Different driving motors have different advantages, such as low cost and convenient speed regulation of brush motors, long service life and low noise of brushless motors, high efficiency and small size of hollow cup motors
 

2) Output power.
The output power of a micro planetary reduction motor is generally around 0.1W-40W, and the power of the driving motor determines the application scenario.
 

3) Diameter specifications.
The diameter specification of micro motors is generally around a few millimeters to tens of millimeters, and the appropriate diameter specification should be selected according to the different application products.
 

4) Working voltage.
The working voltage range of micro motors is around 1.5V-24V, which can meet the requirements of most products in the market. The higher the working voltage, the faster the motor speed.
 

5) Lifespan.

It refers to the continuous working time of micro motors under rated load and no-load conditions. The lifespan of brush motors with carbon brushes is thousands of hours, while brushless hollow cup motors can reach tens of thousands of hours. For applications that require continuous long-term operation, brushless hollow cup motors can be selected, such as electronic locks and other products that can use brush motors.

type
Applicable scenarios
Advantages of planetary gearbox matching
precautions
servo motor
High dynamic and precise positioning (robot/machine tool)
High rigidity vibration suppression, backlash compensation
Requires drivers, high cost
stepping motor
Low cost open-loop control (conveyor belt/indexing plate)
Reduce speed and increase torque to avoid losing steps at low speeds
Poor high-speed performance, prone to overheating
with brush
Simple speed regulation (AGV/small equipment)
Reduce speed and expand torque range
Electric brush wear and low lifespan
brushless
High speed and long lifespan (fan/pump)
Efficient cooperation with gearbox for high torque output
Moderate control complexity
Comparison Table of Motor Types

Installation and Thermal Management

interface matching

The shaft diameter (such as 14mm), keyway/flange (such as IEC B5), and stopper size should correspond exactly.

Heat dissipation capacity

Continuous high torque working conditions require verification of the thermal power of the gearbox (e.g. a certain model has a continuous thermal power limit of 200W).

Avoiding selection traps

Neglecting efficiency loss: actual output torque=theoretical value × η (η≈ 0.85~0.95)

Low frequency resonance: The motor reducer system needs to avoid the natural frequency of the load (notch filtering can be set through a frequency converter)

Axial/Radial Forces: Check if the gearbox bearings can withstand external forces (such as belt side tension)

Practical suggestions

Use selection software (such as Neugart, SEW's online tools) to input parameters for automatic matching.

Request curve chart:

Motor torque speed curve+reducer efficiency curve → Confirm whether the operating point is in the high-efficiency zone.

Prototype testing: High load applications must undergo a 24-hour temperature rise test (shell temperature should be<90 ℃).

Summary: The essence of selection is a closed-loop iteration of load requirements → reducer parameters → motor parameters. It is recommended to prioritize the combination of servo motor and low backlash planetary gearbox for precision transmission, and optimize dynamic response through inertia matching. In industrial scenarios, collaborative simulation with suppliers (such as Simulink or AMESim) can significantly reduce debugging risks.