Planetary Gearbox: Introduction, Working Principle, and Components

What is a Planetary Gearbox?

A Planetary Gearbox is commonly known as Planetary Gear or Planetary Gear Set. It is a high-torque gear system used in many industrial and automation applications. It is designed to reduce speed, increase torque, and manage power flow efficiently between the input and output shaft. 

Its design and operation are based on the concept of planetary motion, where multiple gears revolve around the central gears, similar to the movement of Earth around the sun and work together to transmit the power and torque from one component to another component in an efficient manner.

The key feature of a planetary gearbox is its compactness. Despite its ability to handle high torque loads, the planetary gearbox requires minimal space, making it suitable for applications where space is limited. Its compact design allows for seamless integration into various mechanical systems without compromising the performance of the application. 

Please find a visual representation of what is a Planetary Gearbox and how it works from the YouTube video presented by "3D Printer Academy"

Planetary gearboxes are also known for their exceptional efficiency. The distribution of torque across multiple gears within the system results in smooth and reliable power transmission. This efficiency is crucial in maximising the performance of machinery and equipment while minimising energy losses during the operation. 

Planetary Gearbox is commonly used in automotive transmissions, industrial machinery, robotics, and aerospace systems. Their precise control over speed and torque enables engineers to optimise performance and reliability in complex mechanical systems.

Parts and Components of a Planetary Gearbox

A planetary gearbox is a type of gearbox used to transmit power and torque from the input shaft to the output shaft.

Parts of planetary gearbox consist of sun gear, planet gear, ring gear, and other components that work together, to achieve precise control over the speed and torque of the motor.

The key parts of Planetary Gearbox are as follows:

• Sun Gear

It is an essential part of the planetary gearbox and plays an important role in the function of the gear system. This gear is located at the centre of the gear system and is surrounded by multiple gears. This gear is smaller in size compared to the other gears as it meshes with the teeth of the gears for smooth and efficient power transmission. 

Its main function is to control the speed and direction of the shaft and act as a central point of the gearbox. 

• Planet Gear

An important part of planetary gearbox is the planet gear. Its main function is to provide gear reduction. It has several teeth that surround its circumference. These teeth mesh with the teeth of the sun gear and cause the rotation of the output shaft.

The ratio of the number of teeth of planetary gear and sun gear determines the gear reduction ratio. This ratio is important to achieve high torque at a small size as compared to other gear systems.

• Ring Gear

The ring gear is a large circular gear of planetary gearboxes that acts as a stationary component of a planetary gearbox. It is made up of steel and is responsible for transmitting the power from the input gear to the output shaft. 

The design of the ring gear contributes to the reliability and durability of the gearbox. Its high-strength steel construction helps the gearbox to withstand in high torque and shock load conditions and makes it suitable for heavy-duty applications. 

Mechtex 62P Planetary Gearbox is a 62mm Planetary Gearbox with Metal Gears. It has 12 Nm to 65 Nm Gear Torque and up to 938.85 Gear Ratio. It can combine with various types of motors and is suitable for heavy-duty applications. 

• Carrier

It is another important part of the planetary gearbox. It is a cylindrical structure with holes that hold the planet gear and allow it to rotate around the sun gear. It not only holds the planet gear but also helps in evenly distributing the load on other gears. 

It is a crucial part for the smooth and efficient operation of the gearbox without a single gear being burnt with load. 

Other Components

• Input Shaft

It receives the power from the motor and transfers it to the gears of the planetary gearbox to determine the output speed and torque of the gearbox. It also helps to evenly distribute the load among all the gears 

• Output Shaft

It is located at the end of the planetary gearbox and connected to the final drive or gears. It is made up of high-strength materials to ensure smooth operation and efficient power transmission. 

Planetary Gearbox Assembly 

The assembly of a planetary gearbox involves the precise integration of key components to ensure smooth power transmission.

• Sun Gear Mounting

The sun gear is fixed at the centre and connected to the input shaft. It serves as the driving gear in the system.

• Planet Gears and Carrier

Multiple planet gears are mounted on a rotating carrier around the sun gear. These gears mesh with both the sun gear and the ring gear, distributing the load evenly.

• Ring Gear Installation

The ring gear, with internal teeth, surrounds the planet gears and remains stationary or rotates depending on the design.

• Final Assembly

All components are enclosed in a compact housing. Lubrication is applied, and the gearbox is sealed to ensure long-term durability.

This compact assembly results in high torque output, low backlash, and reliable operation across various industrial and automotive applications.

Applications of Planetary Gearbox 

Planetary gearboxes are widely used across industries due to their compact size, high torque output, and precision control. Below are key applications:

• Automotive Industry

Used in automatic transmissions to provide gear reduction and torque multiplication. Their compact design fits modern vehicle layouts while handling heavy loads efficiently.

• Industrial Machinery

Ideal for conveyors, packaging machines, and CNC equipment, where consistent torque and precise speed control are essential.

• Robotics and Automation

Enables smooth, backlash-free motion in robotic arms and actuators, ensuring high precision in movement and positioning.

• Aerospace Systems

Lightweight yet powerful gearboxes support flight control systems and satellite positioning mechanisms.

• Medical Devices

Used in surgical robots and diagnostic machines where accurate, noise-free motion is critical.

Their efficiency, durability, and versatility make planetary gearboxes essential in applications demanding compact design, high load capacity, and reliable performance.

Why Choose Mechtex for Planetary Gearboxes?

Mechtex is one of India's leading manufacturers of planetary gearboxes ranging from 32mm to 122mm, available in both metal and plastic versions. Our gearboxes are designed for robotics, medical devices, electric vehicles, and industrial automation, delivering high performance, durability, and compactness.