一、前言目前,牙轮钻机已广泛用于大中型金属露天矿,牙轮穿孔成为各大中型金属露天矿最主要的穿孔方法。所谓牙轮穿孔是依靠钻机的回转机构,加压机构施加在钻头上的回转力矩及轴向压力来破碎岩石的。并由压气排碴成孔,也就是说通过加压机构加压使钻头 I. Introduction At present, roller cone drilling rig has been widely used in large and medium-sized open-pit metal, roller cone piercing has become the most important medium-sized open-pit metal perforation method. The so-called roller cone piercing depends on the drilling rig rotary mechanism, the pressure applied to the rotary mechanism and axial pressure on the drill to crush the rock. And by ballast ballast hole, that is pressurized by the pressure to make the drill bit