What is the Importance of Lubrication in Planetary Gearboxes?

What is the Importance of Lubrication in Planetary Gearboxes?
Lubrication is crucial for the proper functioning and longevity of planetary gearboxes. Planetary gearboxes are complex systems consisting of several gears that rotate around each other, transmitting torque and power from one end to another. Lubricants play a critical role in protecting the gears from wear and tear, reducing friction, and dissipating heat generated during operation. Here are some of the key benefits of lubricants in a planetary gearbox.

Preventing Corrosion and Reducing Weariness

Proper lubrication protects gears from corrosion. Lubricant with correct and proper viscosity will form a stable oil film at specified temperature and speed of operation to minimize friction between the gears and preventing them from rubbing against each other and wearing down. This helps extend the precision and life of the gears and ensures that the gearbox continues to operate smoothly.

Minimizing Heat Generation

As gears rotate and contact, they generate heat due to friction. Lubricants help to dissipate this heat and prevent the gearbox from overheating. Overheating can lead to damage to the gears and other components in the gearboxes, and in extreme cases, even cause the gearbox to fail.

Improving Efficiency

Lubricants help reduce friction, which in turn improves the efficiency of the gearbox. A well-lubricated gearbox requires less energy to operate, which can translate into cost savings over the long term.

Preventing Contamination

Particulates ingress and moisture condense may result from the air expands and contracts due to temperature change when the gears are stopped. Such debris and moisture will lead to gears weariness, corrosion and rust eventually. Lubricant also helps to isolate moisture and prevent contamination of the gearbox. It acts as a barrier between the gears and any external particles, preventing them from entering the gearbox and causing damage.

Now we know lubrication is very important to planetary gearboxes, and there are many types of lubricant, what we need to know when choosing lubricant? Here are some important considerations:

Operating Conditions

The operating conditions of the planetary gearbox must be taken into account when selecting a lubricant. Factors such as temperature, load, speed, and environment can affect the performance of the lubricant. High speed and high loading will cause heating in the gearboxes. Therefore, the consideration must be given when selecting a lubricant to ensure that the lubricant will provide protection over the entire operating temperature range of the gearboxes. It is important to choose a lubricant that is specifically designed for the operating conditions of the gearbox.


The viscosity of lubricants drops as the temperature rises. This means the lubricant will get thinner at high temperature, thicker as the temperature decrease.  Lubricant that is too thick at low temperature cannot fully flow inside the gearbox to provide lubrication. Likewise, Lubricant that are too thin at high temperatures cannot produce an oil film on the meshing surfaces of the gears to reduce wear. A lubricant in too thick or too thin viscosity will cause excessive wear of the gears and shorten the service life of the gearbox.


Lubricant typically incorporate various additives to enhance their rust prevention, oxidation resistance, anti-wear, and corrosion resistance properties. If the lubricant cannot withstand high temperatures and oxidizes, acidic substances may be generated, corroding the metal surfaces and causing accelerated gear wear. However, certain additives can form a protective film on the metal surface, potentially reducing gear wear and extending the lifespan of the gearbox.

Materials Compatibility

The gearbox housing, gears and seals of a speed reducer are made up of various types of metals, plastics or rubber materials. Compatibility issues between the lubricant and the materials used in the gearbox must be taken into consideration. Certain lubricant or additives, after prolonged contact with plastic or rubber materials, may cause them to crack or swell, ultimately resulting in oil leakage or damage to the gearbox.

Operating Environment

In certain industries, such as food and beverage, specific regulations may require lubricant used in gearboxes to meet certain standards. In some special application scenarios, gearboxes must operate under extreme conditions, such as very low temperatures, chemical exposure, high levels of dust, or clean room environments. These factors need to be taken into consideration when selecting lubricant. Some lubricating oils provide a wide operating temperature range, allowing the gearbox to perform excellently even in low-temperature environments. Certain lubricating oils offer additional moisture resistance and antioxidant protection to prevent gear rusting.
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In general, using suitable lubricant is crucial for ensuring the smooth operation and extended lifespan of a planetary gearbox, while also reducing maintenance and repair costs. For enclosed or sealed gearboxes in planetary gear systems, Sesame Motor selects specialized fully synthetic lubricating oils designed specifically for gear drives. These lubricating oils offer higher viscosity index, superior lubrication performance, and longer service life compared to general lubricants. With no oil changes required, downtime is minimized, resulting in cost savings. We also offer customized planetary gearboxes and appropriate lubricating oils for special environments such as the food industry, low-temperature conditions, or corrosion resistance. Please feel free to contact Sesame Motor for further information.