The surface of the "Changling" pin has good impact toughness after medium frequency quenching. The surface roughness of the deep hole is improved and the lubrication is smoother by adopting the deep hole machining technology in the middle hole. "Changling" Bushing and inner hole oil groove are formed by crossing single 8-type oil groove, two 8-type oil grooves and 4 ellipses (oil groove is designed according to working conditions), so as to reduce actual contact area between outer diameter of shaft and inner diameter of busher and have sufficient oil stock in the groove to lubricate the pin and bushing. and further improve the service performance of excavator and loader