一台KATO公司产KR20型起重机在坡道上行使时,突然不能前进,换成其他各挡位也不能前进,驾驶员反映最近有时无挡位。由于该机无前进挡,且有时无挡位。于是怀疑、检查电磁液控阀SOL-F线路和电磁线圈,结果无短路、搭铁和烧蚀现象,电磁线圈的电压为标准值24 V,说明电路无故障。拆检液控阀,性能良好。油箱油位也正常。但油质较差,更换油料后试机仍无前进挡位。检测系统压力,启动发动机,加大油门,系统压力升至1.6 MPa,随后迅 When a KATO KR20 crane was used on a ramp, it suddenly failed to move forward and was unable to move forward with the other gears. The driver reported no gear in the recent past. As the aircraft without forward gear, and sometimes no gear. So suspect, check the electromagnetic liquid solenoid valve SOL-F line and electromagnetic coil, the result no short circuit, ground and ablation phenomenon, the solenoid coil voltage of 24 V, indicating that the circuit is faultless. Dismantling the pilot valve, good performance. Tank level is also normal. However, poor quality of oil, the test machine is still no forward gear after changing the fuel. Check the system pressure, start the engine, increase the throttle, the system pressure rose to 1.6 MPa, then quickly