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Spur gear motor VS Planetary gear motor

What’s The Difference Between Spur Gear Motors And Planetary Gear Motors?

The popular gear motor options of spur gear motor and planetary gear motor have their own unique advantages and disadvantages, designed to meet specific application needs. However, if you’re not familiar with these types of gear systems, choosing the right one can be a challenge. Don’t worry, though! We’ll break down the differences and help you select the perfect gear motor solution to elevate your industrial applications to new levels of performance and success. Get ready to unlock the true power of precision and efficiency in motion!

INEED Electronics has over 10 years of experience in designing and manufacturing spur gear motors and planetary gear motors. As a leading manufacturer in the DC gear motor industry, we offer our brushed and brushless DC motors paired with spur and planetary gearheads. The design objective of our gearboxes is to provide cost-effective products without compromising quality.  Submit your gear motor requirements today and let us help make your application more efficient. 

Quick tips on the difference between spur and planetary gear motors:

Spur gear motorPlanetary gear motor
Easily maintained and manufactured
Simple design
Bigger gear ratio range
Bigger gear tooth load
Efficient power transmission
Stability & reliability
ConsNoisy at high speeds
Prone to wear
Low load
Higher unit price

Have you already formed a preference on which motor to choose? Curious about the reasons behind their variations? Keep reading this article to make your decision-making process easier and more straightforward.

Let’s now explore in more detail the distinctions between spur gear motors and micro planetary gearbox motors, focusing on their structure, operating principles, torque and speed characteristics, as well as cost, to provide a comprehensive understanding of their differences.

What is difference in the structure?

Spur gear motors are a type of cylindrical gears, commonly made of brass or steel. The structure of a Spur Gear Motor is simple, consisting of a driving gear and a driven gear that directly engage with each other to transmit power. The gear teeth are straight and connected on parallel axes but offset from each other. The teeth of spur gears have involute profiles, engaging only one tooth at a time, resulting in the load being supported by a single point of contact between the gears. This method of tooth engagement generates high stress and noise. Spur gears excel at providing high torque at lower speeds.

Spur gears may produce noise, especially when there is insufficient lubrication. The size of the gears and the number of teeth on each gear are important considerations in spur gear design. The dimensions and quantity of teeth determine the gear ratio for transmitting output torque and the rotational speed of the shaft.

Spur gear motor structure
Spur gear motor structure

Spur gear head

The gear arrangement of a planetary gearbox resembles the solar system in space, where multiple planet gears rotate around a central sun gear. These planet gears are surrounded by a ring gear, and the teeth of the ring gear mesh with the planet gears. Due to the ability to engage multiple gears at once, a planetary gear motor can handle higher loads.

Depending on the product series, the gears of a planetary gearbox can be made of metal or plastic. Plastic gears are lighter, operate more quietly, and provide a more economical solution. Please check out our 6mm plastic planetary gear motor and 6mm metal planetary gear motor solution.

6mm planetary gear motor
6mm planetary gear motor structure

On the other hand, metal gears can transmit greater forces and have a longer lifespan under the same load. Additionally, they are suitable for use in vacuum and high-temperature conditions. Surprisingly, these two materials can be combined. Typically, plastic gears are installed at the input end of the motor to reduce noise during high-speed operation.

The output shaft of the motor is connected to the first stage of the planetary gearbox, driving its movement. These gearboxes have at least one or more reduction stages. On the ring gear, there is another sun gear that drives more planet gears, which in turn drive the next ring gear, and so on. This allows for a wide range of reduction ratios in planetary gear reduction.

Planetary gear motors have numerous gears and teeth that share the load, resulting in less wear and pressure. This makes them more capable of transmitting a large amount of power without damaging the gears. However, the manufacturing cost of planetary gear transmissions is higher due to the need for more components. While this mechanism leads to higher reliability and lower gear noise, it is usually more complex and difficult to access or repair, making maintenance impractical.

Torque and speed

The two most important parameters of a gear motor are torque and speed. Planetary gear motors typically have higher gear ratios, allowing them to generate greater output torque. In contrast, spur gear motors have lower gear ratios, resulting in smaller output torque. Additionally, planetary gear motors usually offer higher output speeds compared to spur gear motors, which have lower output speeds.

The cost for spur motors and planetary DC motor

Spur gear motors are often cheaper than planetary gear motors because they use fewer gears and are easier to manufacture. Due to the more complex structure of planetary gear motors, they typically have slightly higher costs compared to spur gear motors.


Spur gearboxes are highly regarded for their simple design and cost-effective nature. They are an ideal choice for applications with low torque and low speed requirements, as they can achieve higher efficiency under these conditions. They operate smoothly and are well-suited for applications such as high-precision positioning of optical components or driving door lock systems.

Planetary gearboxes, on the other hand, can transmit higher torque compared to spur gearboxes. If torque is your primary concern, then a planetary gearbox would be the optimal choice. They are compactly designed and offer a high torque-to-weight ratio.

We can manufacture both spur gear motors and planetary gear motors based on your specific requirements. Our engineers are ready to collaborate on your next project, so please reach out to us today!



What is the difference spur gear motors and micro planetary gear motors?

Spur gear motors are simpler in structure and lower in cost than planetary gear motors. Spur gear motors perform well for low torque applications. Torque is limited by the speed of the reduction motor because each gear carries all the load.

Why are planetary gears better?

Planetary gears are considered superior for several reasons.

First, the transmission structure of planetary gears allows them to efficiently transfer the maximum input energy to the desired output. The first stage of the planetary gearbox can achieve up to 97% efficiency.
In addition, planetary gears offer a compact design and high torque transmission capability. Its unique configuration, with multiple planetary gears around a central sun gear, allows for greater torque output while maintaining a compact size. This makes planetary gearboxes ideal for applications where space is limited but high torque is required.
In addition, planetary gear systems provide excellent load distribution because the load is shared among multiple planetary gears. This reduces wear and increases durability, making it suitable for demanding and heavy duty applications.


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