Wind turbine pitch bearing grease selection

In order to ensure safe and reliable operation of the pitch bearing, the work in pitch bearing to minimize friction and wear, avoiding the pitch bearing and the inner surface of the ball channel failure, the bearings must be lubricated. Bearing lubrication and cooling, dust, rust, sealing, cushioning and so on.
Bearing lubrication can be divided into two kinds of grease and oil lubrication. To prolong the life of the pitch bearing, the bearing must be based on the conditions of use, the adoption of appropriate lubrication. Grease has good angular contact ball bearing is not lost, does not drip, compression resistance, sealing against dust resistance, good corrosion resistance and other characteristics. In the low, medium, medium temperature, high load bearing operation using very common. As the pitch bearing condition is a high load, low speed, the pitch of the bearing means are lubricated with grease. Grease is a base oil, thickener and additives between the between the solids and semi-fluid lubricant. In the content of the grease base oil accounts for 80-95%, and only when under pressure grease base oil from the grease to lubricate the flow effect, when the pressure is removed, grease base oil can be re-absorbed, grease lubrication performance is determined by the performance of the base oil. Grease consistency (from soft to hard) inside grease thickener is determined by the number, the liquid may contain only 2% of grease thickener, and the thick grease may contain from about 20% of the thickening agent. The content and type of additives to form a variety of different characteristics of grease, bearing grease are commonly used calcium based grease, sodium grease, sodium calcium based grease, lithium grease, aluminum grease disulfide molybdenum grease and so on.
A pitch bearing according to the actual conditions, the selection of the pitch bearing grease are taken into consideration fat types of additives, the viscosity of oil, grease dropping point,; E13N oil pumping performance and other properties of the needle penetration.