How much do you know about wind turbine bearing?

In recent years, wind power in emerging markets around the world has developed rapidly. Against the backdrop of national policy support and tight energy supply, China's wind power equipment manufacturing industry has risen rapidly, and the market demand for wind power equipment has grown rapidly, which has also driven the development of wind turbine bearings.
Bearings are the core components of wind turbines. Wind turbine bearings range from bearings used in blades, main shafts and yaws to high speed bearings used in gearboxes and generators
Main features of wind turbine bearings
1. Bad use environment.
2. High maintenance cost.
3. High requirement of service life.
Bearings for wind turbines mainly include yaw bearings, pitch bearings, spindle bearings, gearbox bearings, and generator bearings.
Generator bearing
Bearing type: deep groove ball bearings, angular contact bearings.
Working conditions: high speed (1000-1500rpm), high temperature (90-120 °C) heavy load.
Grease requirements: excellent shear stability, good oxidation stability, good wear resistance, excellent low temperature start-up performance.
Spindle bearing
Bearing type: tapered roller bearing, spherical bearing.
Working conditions: low speed (<25rpm), wide temperature range, heavy load, vibration, high humidity.
Grease requirements: excellent wear resistance, good oxidation stability, excellent low temperature start-up performance, good water resistance and so on.
Pitch/yaw bearing
Bearing type: four point contact ball bearing
Working conditions: wide temperature range, heavy load, vibration, high humidity.
Grease requirements: excellent corrosion resistance and wear resistance, excellent low temperature start-up performance, good water resistance, good oxidation stability, etc.
Each wind turbine equipment has 1 set of yaw bearing and 3 sets of pitch bearing (not equipped for the wind turbine below MW), 3 sets of generator bearings (deep groove ball bearings, cylindrical roller bearings), 2 sets of spindle bearings (spheroidal roller bearings), totally 9 sets.
In addition, there are also gearbox bearings. The gearbox has three structural forms. The first type requires 15 sets of bearings, the second type requires 18 sets of bearings, and the third form requires 23 sets of bearings. Thus, the average number of wind turbine bearings is 27 sets.
The structural forms of bearings for wind turbines mainly include four point contact ball bearings, cross roller bearings, cylindrical roller bearings, spherical roller bearings, and deep groove ball bearings. The yaw bearing is installed at the connection between the tower and the cockpit, and the pitch bearing is installed at the joint of the root of each blade and the hub.
Wind power bearing production process
1. Control the forging temperature.
2. Control the modulation process to ensure the mechanical properties.
3. Control the depth of the intermediate frequency quench hardened layer on the surface.
4. Avoid micro cracks on the surface.
The cleaning process of wind power bearing:
1. Inspection of forging blank
2. Rough turning
3. Finish turning
4. Molding finish turning
5. Heat treatment
6. Gear-hobbing and gear-milling processing
7. During drilling, according to customer requirements, it can be treated with blue, phosphating and vulcanization.
8. Rough grinding and fine grinding
9. Demagnetization, cleaning, assembly, surface coating, grease filling,packaging

What causes the bearing cage to break?

The cage/retainer in the rolling bearing plays the role of equidistance separating the rolling elements and preventing the rolling elements from falling, guiding and driving the rolling elements to rotate.
Although the bearing is composed of many bearing parts, the first damaged/failed part of the bearing is often the bearing cage. The cage can be said to be the bearing "blood vessel", because it can evenly distribute the inner ring, the outer ring and the rolling element. The failure or damage of bearing cage will easily shorten the life of the bearing or even damage it. What causes the bearing cage to break?

◐◑ Insufficient bearing lubrication
Lubricating oil or grease is dry without adding in time / daily maintenance, or use the wrong label of the oil or grease.
◐◑ Bearing impact load
The intense vibrations in the impact load create an impact of the rolling elements on the cage.
◐◑ Bearing cleanliness
The bearing is not well sealed in the bearing box, and then dust may enter; the friction between the rolling element and the cage may be added, thus causing damage to the cage.
◐◑ Installation problem
The bearings are not installed correctly and damage the cage during installation.
◐◑ Bearing creep
Creep mostly refers to the sliding phenomenon of the ring. Under the condition of insufficient interference of the matching surface, the load point moves in the surrounding direction due to sliding, resulting in the deviation of the ring from position of the shaft or the outer casing towards the circumference direction.
Improper installation, the inclination, and too large interference will easily cause clearance reduction, increasing friction heat production, surface softening, and the abnormal peeling occurs prematurely. As peeling spreads, the foreign matter is peeled off into the pocket of the cage, resulting in the blockage of cage operation; the generation of additional loads increased the wear of the cage, and such a deteriorating cycle can cause the cage to break.
◐◑ Bearing cage material defect
Cracks, metal inclusions, shrinkage cavities, air bubbles and riveting defects, nails, padding, severe riveting, etc. may cause the cage to break.
◐◑ Intrusion of hard foreign objects
The intrusion of foreign hard foreign objects or other foreign matter increase the wear of bearing cage.
Bearing cage performance varies with cage materials and molding technology, ZYS can supply all types of bearing cage to meet the requirements of different applications. Besides the textile laminated phenolic resin, porous polyamide and PTFE engineering plastic, and other plastic cage materials, we can also supply finished cages according to the drawings provided by customers. For more information, please send email to zysdong@gmail.com or visit our website www.zysbearing.com.

Which type of bearing is less noisy?

The noise of bearing not only affects the bearing operation, but also brings a lot of trouble to the mechanical equipment. The intrusion of foreign materials will directly cause certain noise during the operation of the bearing, and the improper lubrication and wrong bearing installation will also cause bearing noise. Which kinds of bearings have less noise?

1. The noise of the ball bearing is lower than that of the roller bearing, and the friction noise of the bearing with less sliding is lower than that of the bearing with relatively more sliding; the bearing with more balls and thick outer ring also has smaller noise.

2. The noise of bearing with solid cage is relatively lower than that of a bearing using a stamped cage.

3. The noise of bearing with the plastic cage is lower than that of the bearings using solid cage or stamped cage.

4.Bearings with high precision, especially those with higher precision rolling elements, have lower noise than low precision bearings.

5. The noise of small bearings is relatively small compared to the noise of large bearings.

In order to maintain the good performance of the bearing, daily maintenance, inspection, overhaul, and prevention must be done. For long-running equipment, the usual inspection and tracking is particularly important, including the rotation of the bearing, vibration, temperature, lubricant status, etc. According to the test results, equipment maintenance personnel can find and deal with problems in time. ZYS will carefully analyze the technical information and application of bearing offered by the customer, and then choose the right type of bearing and inform the precautions during installation and operation. If you want to know more information, please send email to zysdong@gmail.com or visit our website: www.zysbearing.com.