目前国内全液压钻车的自动防卡装置如图1所示。它是在推进回路中设一个液控的两位四通换向阀,即防卡钎阀。它的液控口接到转钎回路中。当转钎油马达正常工作时,防卡钎阀处于正常推进位置;卡钎时,转钎阻力矩增大,转钎回路的油压升高,当超过防卡钎调定压力值时,防卡钎阀立即转向,凿岩机后退,使转钎回路的油压降低到正常值,油马达恢复 At present, the entire domestic hydraulic drilling car anti-card device shown in Figure 1. It is in the promotion of a liquid-controlled two-way four-way valve, that is, anti-card solder valve. Its pilot port connected to the brazing circuit. When the converter oil motor work properly, the anti-brazing and brazing valve is in normal pushing position; when brazing, the brazing torque increases, and the oil pressure in brazing circuit increases. When it exceeds the anti-brazing pressure, the anti- Brake valve immediately turned steering, rock drill backwards, so that the pressure of the drill rod circuit to normal, the oil motor recovery