Solution 1 Sealing ring 1.1 Choose reliable sealing ring materials The key performance of domestic sealing rings, such as anti-aging and anti-wear, is still far behind that of foreign countries. At present, most wind turbine manufacturers use imported sealing ring materials with high cost. 1.2 Improve the structure of the sealing ring At present, most of the pitch bearing sealing rings in China use a structure similar to double lips, as shown in Figure 4, the structure is simple, and the ability to prevent internal grease leakage is limited, so the optimization is based on the original structure. The lip structure is changed to a multi-lip structure (Figure 5), and two straight sealing lips are added to enhance the leakage prevention effect. The installation schematic diagram is shown in Figure 6. Figure 4 The original sealing structure of the pitch bearing 1—boss; 2—main sealing body; 3—dust lip; 4—third oil seal lip; 5 — second oil seal lip; 6 — first oil seal 7—the 1st straight sealing lip; 8—the 4th oil seal lip; 9—the 2nd straight seal lip Figure 5 The schematic diagram of the cross-section of the new type of anti-leakage seal Figure 6 The schematic diagram of the installation of the new type of anti-leakage seal The first oil seal The front end of the lip is in close contact with the outer surface of the inner ring of the pitch bearing, and the end is in close contact with the inner surface of the outer ring. The gap between the first seal oil lip and the inner and outer rings leaks. The 2nd and 3rd sealing oil lips are fish tail-shaped, they are in contact with the sealing groove on the outer surface of the inner ring, and there is a small gap between them. To ensure the normal rotation of the pitch bearing, and to prevent the grease leaking from the first sealing oil lip from continuing to leak out. The fourth seal oil lip is in contact with the groove of the outer ring, which can prevent the grease leaking from the pitch bearing from continuing to leak out. The shape of the dust lip is in the shape of a fin, and the end is in close contact with the outer surface of the inner ring. The dust lip has the characteristics of two-way protection, which can not only prevent the leaked grease from continuing to leak to the outside, but also prevent dust, impurities or other harmful substances in the air from entering the pitch bearing, causing the channel to wear or heat to get stuck, resulting in Wind turbines cannot work normally, and even major accidents occur. The first and second straight sealing lips are in contact with the surface of the outer ring, which can prevent the leaking grease from continuing to leak out. The boss is located on the main sealing body, the upper surface is flat, and the operating space of the installation tool is reserved between the dust lip and the dust lip. The operating tool with a roller structure can be used to roll back and forth along the upper surface of the boss to compact the sealing ring. , so as to ensure the sealing effect of the sealing ring. The overall shape of the new anti-leakage sealing ring is fishbone-shaped. It adopts 1 dust lip, 4 oil sealing lips and 2 straight sealing lips, which can effectively prevent the grease inside the bearing from leaking out. 1.3 Reasonable maintenance and timely replacement of damaged or aged seals. The seals must be installed or maintained in strict accordance with the prescribed process to avoid unqualified installation or damage to the seals. Check the sealing ring of the pitch bearing with grease leakage. If the sealing ring is found to be aging, severely worn, damaged, warped, etc., it is necessary to clean up the leaking grease in time, and replace the new sealing ring according to the process requirements. 1.4 Reduce the size of the stretching head of the hydraulic stretcher and conduct technical communication with the supplier of the hydraulic stretcher to reduce the overall size of the stretching head to avoid extrusion and damage to the sealing ring during the on-site operation of the hydraulic stretcher; further standardize the on-site installation process and add a Item 'During the field operation of the hydraulic stretcher, check the distance between the stretching head and the sealing ring'. 2 Improve the internal structure of the pitch bearing 2.1 Groove at the bottom of the channel The design of the pitch bearing channel structure not only affects the fluidity of the grease in the internal channel of the bearing, but also affects the diameter of a section of the grease drain hole connected to the channel. The fluidity of grease is related to the cross-sectional shape and area through which it flows. The smaller the cross-section, the worse the fluidity. The internal structure of the pitch bearing channel designed by a supplier is shown in Figure 7a. The bottom of the groove is all arc transitions. It has been verified by the wind field that this channel cross-sectional shape is not conducive to the flow of grease at the bottom of the groove. The improved cross-sectional shape of the channel is shown in Figure 7b, and a rectangular groove is added to the bottom of the groove, thereby increasing the fluidity of the grease. The test results show that the grease can be smoothly discharged from the grease discharge hole after the channel cross-sectional shape is improved, and the sealing ring has no bulge and grease leakage. Figure 7 Channel structure of a pitch bearing 2.2 Improve the size and distribution of grease holes in the bearing 1 mm, and the size of the grease drain hole is M14mm×1.5 mm. When there are special requirements, the number, location and size of the grease drain hole shall be determined by the bearing manufacturer and the wind turbine manufacturer through negotiation. The structure of the grease injection hole and the grease discharge hole is shown in Figure 8. Fig. 8 Schematic diagram of the structure of grease injection hole and grease discharge hole It can be seen from Fig. 8 that the entire grease discharge channel is a stepped structure, which is divided into the threaded hole part on the outside of the bearing connected to the grease collection bottle and the light hole near the inside of the bearing and connected with the channel part.