LYHG extra large bearings four point contact or cross cylindrical roller slewing bearing seat in yaw strusture of the bottom of the windwill generator to adjust the angle of wind timely,letting the thunder to the earth.The mafor load supported radial load,axial load and tilting moment.The requirements come up to good seal,reliability,rotate nicely and stably,the surface anti-corrosion for over 20 years life.