What Is a Planetary Gearbox and How Does It Work

Planetary gearboxes are special motion control tools typically used by vehicles as an essential piece of automatic transmission equipment. Specifically, planetary gearboxes are a form of gearbox where the input and output have the same center of turning. This formation has several gears spinning in one direction and “orbiting” an interior gear, giving planetary gearboxes their name. This blog provides a short overview of planetary gearboxes, so that way you can best make an informed decision when considering multiple components for your assembly.

At its base level, a planetary gear box is a combination of interconnected gears organized so that the input and output shafts are aligned. This design makes the planetary gearbox an effective way of transmitting high torque in the most compact shape. With its cylindrical form and in-line shafting, planetary gearboxes are often seen as compact alternatives to normal pinion-and-gear reducers. They are suited for a wide range of applications, from usage in automobile wheel drives to hydraulic motors and electric screwdrivers.       

As stated before, the name planetary gearbox refers to how the various gears move in a set together. There is a satellite (ring) gear, a sun (solar) gear, and two or more planet gears in a planetary gearbox. The sun-gear functions as the input, turning on the centermost shaft. Surrounding the sun-gear are the planet gears bolted into the planet carrier to form the output shaft. In comparison with the sun and planet gears, the satellite gear stays in the same place and has a set of internal grooves which the planetary gears move along. These terms are helpful for understanding the arrangement, but it should be noted that in industrial operations, the sun gear is called the input shaft, while the planet gears and carrier form the output shaft. Lastly, the satellite part (or ring gear) is called the housing.

When the device is working, input power to the sun gear results in spinning that turns the planetary gears around it. With external teeth on the sun gear and internal teeth on the satellite gear, the planetary gears can smoothly orbit the sun gear as they turn in the same direction. Though this is a relatively simple arrangement, the many teeth operating simultaneously provide a high-speed reduction to be achieved with comparatively smaller gears and lower inertia reflected back to the system. Having several teeth share the load also allows planetary gearing to transfer higher levels of torque than other gearbox arrangements. Overall, the combination of large speed reduction, compact size, and high torque transmission make planetary gearboxes a dependable option for compact operations.

When you are considering different types of gearboxes for an assembly, planetary gearboxes offer several key benefits which could be useful in space-constrained areas. Here on Veritable Aerospace, we are a leading supplier of planetary gearboxes and other machinery components; our items have been tested for their durability and function to guarantee immediate implementation upon arrival. If you are currently on the search for reliable machinery parts, we invite you to browse our online catalog of available products and make use of our Instant RFQ service to receive competitive quotes for your comparisons. Our team of experts are available 24/7x365 to answer customer inquiries and requests, meaning we will reply to submitted RFQ forms in just 15 minutes or less!