The number of wind turbines used to create energy has been increasing within the last few years. In order for these wind turbines to work correctly, people use bearings to ensure the turbines keep on turning. They are actively apart of a number of parts of the machinery and play different roles. This means there is a great variety of bearings in each turbine.
Typically, bearings have two different groups, plain bearings, and rolling bearings. Plain bearings generally do not have moving parts so the movement happens between the bearing and a supporting part. In contrast to plain bearings, rolling bearings contain moving parts.
The motion happens between rolling elements and the raceways to support radial and axial loads. Today, most wind turbines solely use roller bearings because of their greater versatility. Below is a breakdown of the most common applications used in wind turbines.
Cylindrical roller bearings designs vary immensely. Manufacturers offer in single roller row models along with designs all the way up to four roller rows. The higher the number of rows in a model means they can support higher radial loads at moderate speeds.
Single roller bearings containing a cage are able to withstand slightly lower radial loads at higher speeds. The best uses for cylindrical roller bearings are in generators and gearboxes.
Generally, spherical roller bearings have two rows of rollers that run in two raceways. With this type of design, they are able to withstand both high axial and radial loads and reduce friction and consequent heat all at the same time.
The main shaft of a wind turbine usually uses spherical roller bearing but gearboxes use them before.
Deep groove ball bearings are a very common type of bearing that is able to appear in a number of different applications. These bearings facilitate radial and axial loads in both directions. Because they contain a deeper groove, they can deal with higher speeds.
This makes them a perfect fit for generators and electric motors in wind turbines. People can also coat deep groove ball bearings in order to stop the effects of electrical erosion.
Tapered roller bearings consist of tapered rollers. The inner and outer raceways of tapered rollers are also tapered. The number of rows that this type of bearing can have is usually one to four. These bearings' designs allow them to deal with tilting movements while reducing vibrations within the machinery.
The main use of tapered roller bearings are for gearboxes because of their durability in conditions generally found in operational gearboxes, for example, high vibration levels. Another way people can use them as the main shaft bearings.
The slewing bearing is a large component with a diameter of 3-6 meters with gear teeth on the outer rings. This type of bearing usually has multiple rows of rollers and must be very robust.
People design slewing bearings for heavy rotating machinery and allow the nacelle in the turbine to rotate at a regulated pace for maximum energy output. They are also used in the pitch and yaw applications and can survive horrible weather conditions.
Wind turbines are a great way to create energy with little pollution. It is amazing that bearings have such an impact on a clean energy source.