In rock drilling process with percussion-rotary drill rotating drilling tool bears two toques: dynamic torque which drives drilling tool into rock mass, and resistance torque of rock mass.

前言：在冲击—回转式凿岩机向岩石钻进过程中，旋转中的钻具承受着两种力矩的作用：一是驱动其旋转的动力矩；二是被钻岩石阻止其旋转的阻力矩。

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The rock stratum drilled by a rotary drill is random distributed and complicated, so it is difficult to define the drilling process.

牙轮钻机钻凿的岩层是随机分布、错综复杂的，因而钻进过程难以定义。

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For small rotary rock drill bits and rotary prospecting bits to cut soft, medium-hard rock.

用于中小规格冲击钻及旋转勘探钻具，凿进软岩层、中硬岩层。

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