大多数国产凿岩机都是在活塞回程时转动钎具。这时,活塞带动转钎机构所产生的扭矩,必须克服钎具旋转的外部阻力。通常,多用螺旋副公式计算转钎扭矩 M_B=p_c·ir·tg(β-p) (1)式中p_c——回程时活塞上的平均作用力; Most domestic rock drills turn the brazing tools on the return stroke of the piston. At this moment, the piston drives the torque produced by the brazing mechanism and must overcome the external resistance of the brazing tool to rotate. In most cases, the helical torque formula M_B = p_c · ir · tg (β-p) (1) is used to calculate the average torque of the piston on the return stroke.