Kaydon Developed Bearings Meet Wind Power Needs

Kaydon Developed Bearings Meet Wind Power Needs RA Rodriguez is the UK factory representative for Kaydon, an American bearings specialist which has just received its largest ever renewable energy order. Kaydon has developed a range of bearing types that best meet critical pitch, yaw and gearbox applications in land-based or offshore systems from 200kW to 5MW and beyond. The typical requirement is for a large slewing ring - a large diameter bearing with a large bore - in diameters ranging from 2 to 5m.To combine the function of a bearing and gear, teeth can be cut into the inner or outer race to rotate with the assembly or remain stationary in respect to the ground during operation. The use of a single, larger diameter bearing allows wiring and other services to pass through the bore with ease.This simplifies the overall system design, improves outward appearance and protects components. Selecting the right bearing design depends on load, stiffness, speed, size and the smoothness of rotation required.One that has proven to be particularly popular for wind turbines is the four-point contact ball bearing.This bearing accepts combinations of radial, thrust and moment loads. It uses races shaped like gothic arches on both the inner and outer race ball paths that generate four points of contact on each ball.To satisfy requirements for maximum load capacity within a given envelope, especially in larger sized bearings, Kaydon has also developed an eight-point contact bearing that is also widely used in wind turbines.This is an annular bearing with two rows of balls which uses the gothic arch internal geometry in both rows.This additional row increases load capacity by an additional 80%. Naturally corrosion resistance is an important consideration for outdoor use and the Kaydon wind turbine bearings are therefore available with a range of surface treatments to meet the conditions of the application. Selection of the most appropriate materials is also critical for operating temperatures that may be as low as -40C.Sealing arrangements are available for severe conditions. While other manufacturers may specialise in one or two specific bearing types. Kaydon has the experience and manufacturing flexibility to match the product to the exact requirement.This includes accommodating special needs without sacrificing system performance or increasing cost.