A gearbox motor, also known as a gear motor, is a high-torque low-speed motor that combines a gearbox with an electric motor. The combination of motor and gearbox can provide customers with thousands of ratios of motor output torque and speed. Therefore, gearbox motors are mainly used in high-torque, low-speed precision transmission fields.


Types of Gearbox Motor
A gearbox motor is a special type of electric motor that produces high torque while maintaining low horsepower (or low speed). The function of the gearbox is to increase the output torque of the gearbox motor by reducing the speed of the output shaft end of the motor.
Gearbox motors come in a variety of types, each with their unique advantages, reduction structure, and applications. These include, but are not limited to:
Note: The choice of gearbox type is entirely dependent on the specific needs of the application. For the selection of gearbox motors, there is no fixed solution, only the most suitable one. DONCEN MOTOR focuses on the development and manufacture of gearbox motors. For 20 years, we have provided customers with the most cost-effective gearbox motors.

What’s Inside a Gearbox?
The gearbox is an integral mechanical structure based on the gear transmission system. Gearboxes include but are not limited to: Gearbox gears, Gearbox shaft, Gear Lubricating oil, Gearbox shafts, Spacers, Gearbox bearings and Gearbox housings.
Component Name | Function Description |
---|---|
Gears | Transmit power and adjust speed ratio |
Gearbox Shaft | Connects gears and transmits torque |
Lubricating Oil | Reduces friction, minimizes wear, and extends lifespan |
Gearbox Housing | Protects internal components and provides structural support |
Spacers | Adjust clearance and reduce wear |
Bearings | Support rotating parts and reduce friction |
1.Gearbox Gears
The gears in micro gearboxes are mainly low modulus, high precision gears. From the analysis of gear materials, the mainstream micro gear materials on the market are mainly composed of three types – plastic – iron alloy – steel alloy.



Material Type | Gear Strength | Self-Lubrication | Temperature Resistance | Corrosion Resistance | Noise Level | Processing Method |
---|---|---|---|---|---|---|
Plastic Gears | ▮▯▯▯▯ ( | ▮▮▮▮▯ | ▮▮▯▯▯ | ▮▮▮▮▮ | ▮▮▮▮▯ | Injection Molding |
Iron Gears | ▮▮▮▯▯ | ▮▯▯▯▯ | ▮▮▮▯▯ | ▮▮▯▯▯ Oxidation | ▮▮▯▯▯ | Powder Metallurgy |
Steel Gears | ▮▮▮▮▮ | ▮▯▯▯▯ | ▮▮▮▮▮ | ▮▮▯▯▯ Oxidation | ▮▮▮▯▯ | Hobbing |
Note:The selection of gears needs to take into account the characteristics of the gear material itself as well as the gear accuracy and processing cost. Doncen Motor provides gear selection suggestions for micro gearboxes. Our professional gear engineers will provide valuable gear selection suggestions based on your application and needs.
2.Gearbox Shaft
Gearbox shaft is a critical component of the gearbox motor as it connects the motor to the application or device it is powering, enabling the transmission of mechanical energy.



In the gearbox motor, the output shaft is responsible for outputting torque, bearing load, and connecting application equipment. Therefore, the output shaft is the key connection accessory in the micro gearbox.
Related Article: Micro Gearbox selection guide – How to choose gearbox shaft
3.Gearbox Bearing
Bearings are critical components in a gearbox motor. Bearings have the following main functions
Benefit | Description |
---|---|
Friction Reduction | Minimizes friction for smooth movement. |
Load Support | Supports radial and axial loads. |
Efficient Rotation | Enables free shaft rotation. |
Alignment Maintenance | Keeps the shaft aligned, preventing damage. |
Heat Management | Helps dissipate heat, prolonging life. |
Vibration Reduction | Reduces vibrations for quieter operation. |


4.Gear Lubrication
The lubrication system used inside the gearbox is mainly lubricating oil, which can reduce the friction in the gear transmission system. Effectively protect the life of the gears and reduce the noise emitted by the gear box during transmission.
Property | Mineral Oil | Synthetic Oil (PAO) | Synthetic Oil (Ester) |
---|---|---|---|
Viscosity Grade (ISO VG) | ISO VG 68 | ISO VG 68 | ISO VG 68 |
Viscosity Index (VI) | 95 | 160 | 180 |
Thermal Stability | – Flash Point: 200°C | – Flash Point: 240°C | – Flash Point: 250°C |
– Oxidation Life: 1000 hours | – Oxidation Life: 3000 hours | – Oxidation Life: 3500 hours | |
Low-Temperature Fluidity | – Pour Point: -15°C | – Pour Point: -45°C | – Pour Point: -48°C |
– Cold Start Torque (-20°C): >20 N·m | – Cold Start Torque (-30°C): <10 N·m | – Cold Start Torque (-40°C): <8 N·m |
5.Gearbox Casing
The gearbox housing is the housing used to house all the accessories of the gearbox. The main function of the casing is to provide mechanical support for the components that are driven in it, and to provide protection for these internal components from external interference.
Material | Advantages | Disadvantages |
---|---|---|
Aluminum Alloy | ✅ Lightweight ✅ Corrosion Resistance ✅ Heat Dissipation ✅ Strength | ❌ Higher Cost ❌ Wear |
Zinc Alloy | ✅ High Strength ✅ Precision | ❌ Heavier ❌ Corrosion |
ABS Plastic | ✅ Cost-Effective ✅ Lightweight ✅ Design Flexibility | ❌ Heat Resistance ❌ Strength |
Choose the housing material based on specific application needs (e.g., heat dissipation, load capacity, budget)
Related Article – What is a Gearbox Housing (Gearbox Casing)
Application of Gearbox Motor
Micro gear motors are suitable for most low speed, high torque fields. We can see gearbox motors in various automation fields.
How to Select the Right Motor for Your Gearbox
Selecting the right motor to pair with your gearbox is critical for achieving optimal efficiency, performance, and reliability. An incorrect match can lead to system inefficiencies, premature wear, or even failure. Follow these steps to ensure a proper selection:
Step 1: Define Your Requirements
Before selecting a motor, clearly define the operational needs of your application:
- Power: Determine the required power output (in watts or horsepower).
- Speed: Identify the desired operating speed (RPM).
- Torque: Calculate the torque needed to drive the load.
- Environmental Factors: Consider temperature, humidity, and exposure to dust or chemicals.
- Duty Cycle: Evaluate how often and how long the system will operate (continuous or intermittent).
- Install Size: Consider the size of the motor from the perspective of mounting dimensions.
Step 2: Choose the Right Motor Types
Select a motor type that aligns with your application’s requirements:
- DC Brush Motor:
- BLDC Motor (Brushless DC Motor):
- Outrunner BLDC Motor
- AC Motor
- Stepper Motor
- Servo Motor


Step 3: Select the Gearbox
Match your motor with a gearbox that complements its performance:
- Spur Gearbox:
- Planetary Gearbox:
- Worm Gearbox:
- Harmonic Gearbox:
- Cycloid gearbox:


Step 4: Calculate Gear Ratios
Ensure the gear ratio aligns with your system’s requirements:
- Use the formula: Gear Ratio = Motor Speed ÷ Output Speed.
- A higher gear ratio increases torque but reduces speed, while a lower ratio does the opposite.
Step 5: Test and Validate
After pairing the motor and gearbox, conduct thorough testing to validate performance:
- Measure output speed, torque, and efficiency under real-world conditions.
- Adjust the system as needed to optimize performance and reliability.
For a comprehensive guide on gear motor selection, check out our Gear Motor Selection Guide.
Conclusion
Understanding the gearbox motor, its components, its types, and how to match it with a motor is integral to leveraging its capabilities. At Doncen Motor, we excel in providing a wide range of high-quality gearboxes and motors that can meet various applications. Explore our catalog to find the perfect motor and gearbox for your needs today!
Author’s Note: This article has been written with the engineer’s perspective in mind, considering the logic and precision that drives our field. It aims to provide a comprehensive guide to gearbox motors for both seasoned engineers and novices in the field. As always, if you have any queries or need further assistance, feel free to contact us.
Thanks SGMADA for the technical guide for this article.