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/*728*90 created on 2018/5/16*/ var cpro_id = "u3440131"; Home>Bearing knowledge>Analysis of the application of wind energy gearbox bearings Analysis of the application of wind energy gearbox bearings
At present, the wind turbine gearbox is an important part of the whole wind turbine. Because it is affected by variable load and strong gusts all year round, it is different from the normal gearbox in production, drawing and protection. The application theory at home and abroad indicates that Among all the components of the wind power gearbox, the bearing is one of the thinnest links. Therefore, the necessary analysis of the bearing is an important method to ensure the reliability of the gearbox. /*250*250 was created on 2017/12/25*/ var cpro_id = 'u3171089';
A smooth analysis of a wind turbine gearbox bearing is well known. The input shaft speed of a wind turbine gearbox is usually 10-20 rpm. Because the speed is relatively low, it is often difficult to form the oil film of the input shaft bearing, which is the planet carrier support bearing. It is to separate the two metal touch surfaces when the bearing works, to prevent metal and metal from directly hitting the touch. We can introduce a parameter λ to characterize the smoothing effect of the bearing (λ is the ratio of the thickness of the oil film to the sum of the roughness of the two touch surfaces) If λ is greater than 1, it is clarified that the thickness of the oil film satisfactorily separates the two metal surfaces, and the smoothing effect is outstanding. If λ is less than 1, the thickness of the oil film is not sufficient to completely separate the two metal surfaces, and the smoothing effect is not ambivalent. Because the wind power gear box ISOVG320 viscosity cycle smoothing oil is usually used, so if λ is less than 1, we can only improve the smoothing effect by reducing the roughness of the bearing raceway and roller. In addition, when the gearbox is drawn, the planet carrier supports the bearing. Try to prevent the scale of one end bearing from being too small. In practice analysis, we found that even if the life expectancy is satisfactory, this depiction will also invite Line speed is very low for small bearings, the oil film can not form even more.
The analysis of the load-bearing area of ​​the bearing of the second wind power gearbox usually only takes part of the load of the roller of the working bearing, and some of the areas of the roller are called the bearing area of ​​the bearing. The load accepted by the bearing is large, and the working clearance is The size will have an impact on the carrying area. If the size of the carrying area is too small, the roller will simply slip in the practice. For the wind power gear box, if the drawing of the main shaft is a double bearing support plan, then in theory, Torque is transmitted to the gearbox. Under this condition, after a brief analysis of the force, it is not difficult to find that the load received by the planet carrier support bearing is relatively small, so the bearing area of ​​the bearing is often small, and the roller has a simple slip. Currently, in the description of wind turbine gearboxes, the carrier support bearings usually use two single-row tapered bearings or two full-roller cylindrical bearings. We can reduce the cylindrical roller bearing clearance by properly pre-tightening the tapered roller bearings. The way to improve the carrying area.
In addition, the analysis of the load-bearing area can help us know whether there is a problem with the double-row bearing. There are many plans for the wind turbine gearbox manufacturer to use tapered roller bearings and cylindrical roller bearings on the high-speed shaft. The plan deals with the problem of simple pitting and shedding of ball bearings in the traditional ball bearing and cylindrical roller bearing plan. However, it is necessary to pay attention to a problem in this plan, that is, to prevent the double row tapered roller bearing from being attacked by a single row. Representation. Double row tapered roller bearings have a large damage to the single row: on the one hand, the bearing load of the bearing is greatly reduced, and then the fatigue life is drastically reduced. On the other hand, the unloaded roller is simply in a slip condition. After analyzing the bearing area, we can know whether the selected double row tapered roller bearing can have the problem of single row bearing, and can adopt the alignment method. The speed of the high speed shaft of the wind power gear box is usually 1100-2000 rpm. /min, because the speed is relatively high, the clearance value selected by the bearing is usually larger than that of other bearings, but the clearance is relatively large and simple The status of the column.
If it is found that the appearance of a single-row bearing does exist, then it is possible to consider the use of tapered bearings with different cone angles. In summary, the analysis of the bearing bearing area can help us better understand the working condition of the bearing in order to optimize the bearing selection and Improve the depiction of the gearbox.
Three Wind Power Gearbox Bearing Stress Analysis The difference between the wind turbine gearbox and the normal gearbox is the irregularity of the received load. Taking the 1.5 MW gearbox currently prevailing in China as an example, the nominal power value is usually 1660 KW. However, the maximum power value in the load spectrum can usually reach about 5000KW, which is about three times the nominal power value. The maximum power value of the swing can usually reach about twice the nominal power value, and they are often used to carry out the safe static load coefficient. Check. In the case that the power value is much larger than the nominal power value, the probability of bearing stress gathering will be greatly increased. This appearance is especially outstanding at the low speed center axis. The reason is that the low speed center shaft usually uses a hollow shaft, and the stiffness is relatively high. Poor, simple to present a situation of partial pain, and partial pain can aggravate the episode of stress gathering.
The above is mainly aimed at the application characteristics of wind turbine gearboxes. From the aspects of bearing bearing area, smoothness, stress gathering, etc., it is necessary to pay attention to several key points that must be paid attention to in the selection and analysis of wind turbine gearbox bearings. It is expected to prevent this. Speaking of some difficulties, then improve the reliability of the wind turbine gearbox, drop the fan stop time.
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Analysis of the application of wind energy gearbox bearings
Source: China Bearing Network Time: 2017-10-28