In the past few years, the number of wind turbines used for power generation has been increasing. In order to ensure the normal operation of these wind turbines, bearings are used to ensure their continuous rotation. They actively separate from many parts of the machine and play different roles. This means that each turbine has various types of bearings.
Usually, bearings are divided into two groups, namely sliding bearings and roller bearings. Sliding bearings usually have no moving parts, so they move between the bearing and the supporting components. Unlike sliding bearings, roller bearings contain moving parts.
The motion between the rolling element and the raceway supports radial and axial loads. Nowadays, most wind turbines only use rolling bearings because of their stronger versatility. The following is a classification of commonly used applications in wind turbines.
Cylindrical roller bearings
The design of cylindrical roller bearings has undergone significant changes. They are single roller row models and designs provided by manufacturers, all the way up to four roller rows. The more rows in the model, the higher the radial load they can support at moderate speeds.
Single roller bearings with cages can withstand slightly lower radial loads at higher speeds. The ideal use of cylindrical roller bearings is in generators and gearboxes.
Spherical roller bearings
Generally speaking, spherical roller bearings have two rows of rollers running on two raceways. With this design, they can withstand both high axial and radial loads simultaneously, reducing friction and the resulting heat.
Spherical roller bearings are commonly used bearings on the main shaft of wind turbines, but were previously commonly used in gearboxes.
Deep groove ball bearing
Deep groove ball bearings are a very common type of bearing that can be used in many different applications. These bearings help with radial and axial loads in both directions. Because they contain deeper grooves, they can handle higher speeds.
This makes them very suitable for generators and motors in wind turbines. Deep groove ball bearings can also be coated to prevent the influence of electrical corrosion.
Tapered roller bearing
The tapered roller bearing is composed of tapered rollers, which are conical in shape, and the inner and outer raceways are also conical. The number of rows for this type of bearing is usually 1 to 4 rows. The design of these bearings allows them to handle tilting motion while reducing internal vibration of the machine.
The main use of tapered roller bearings is in gearboxes, as they have durability under common conditions in operating gearboxes, such as high vibration levels. Another method is to use it as a spindle bearing.
Slewing support
The rotary bearing is a large component with a diameter of 3-6 meters and gear teeth on the outer ring. This type of bearing usually has multiple rows of rollers and must be very sturdy.
Rotary bearings are designed for heavy-duty rotating machinery, allowing the engine compartment in the turbine to rotate at a specified speed to achieve high energy output. They are also used in pitch and yaw applications and can survive in harsh weather conditions.
Wind turbines are a great way of energy production with minimal pollution. Surprisingly, bearings have such a significant impact on clean energy.
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