In the working process of the underground loader, if the oil pressure is lower than 0.2MPa, stop the machine immediately to find out the cause, and continue to work after troubleshooting, otherwise it will cause serious mechanical accidents such as tile burning and cylinder pulling. Generally speaking, what are the reasons for the low oil pressure of the loader?

井下装载机的机油压力过低的原因：

The reasons for low oil pressure of underground loader are as follows:

①机油油量不足：若机油油量不足，会使机油泵的泵油量减少，导致机油压力下降，加剧曲轴与轴承、缸套与活塞的磨损。而如果发动机温度过高，不但加速机油老化、变质，也容易使机油变稀，导致油压下降。

① Insufficient oil quantity: if the oil quantity is insufficient, the oil quantity of the oil pump will be reduced, resulting in the decrease of oil pressure, and aggravating the wear of crankshaft and bearing, cylinder liner and piston. If the engine temperature is too high, it will not only accelerate the aging and deterioration of the oil, but also make the oil thinner, resulting in the decrease of oil pressure.

②机油泵停转或泵油量不足：如果机油泵的驱动齿轮与驱动轴的固定销断裂或配合键脱落，以及机油泵吸入异物而将泵油齿轮卡住，都会使机油泵停止运转，机油压力也随之降为0。

② The oil pump stops running or the pump oil quantity is insufficient: if the fixed pin of the drive gear and the drive shaft of the oil pump breaks or the matching key falls off, and the oil pump sucks foreign matters and blocks the oil pump gear, the oil pump will stop running and the oil pressure will drop to 0.

③机油滤油器堵塞：当机油因滤油器堵塞而不能流通时，设在滤油器底座上的安 全阀就被顶开，机油便不经过滤而直接进入主油道。如果安 全阀的开启压力调得过高，滤油器被堵塞时，安 全阀就不能及时打开，于是机油泵压力升高，主油道供油量减少，引起油压下降。

③ Oil filter blockage: when the oil cannot flow due to the blockage of the oil filter, the safety valve on the base of the oil filter will be pushed open, and the oil will directly enter the main oil passage without filtering. If the opening pressure of the safety valve is adjusted too high and the oil filter is blocked, the safety valve can not be opened in time, so the oil pump pressure increases and the oil supply quantity of the main oil passage decreases, causing the oil pressure to drop.

④回油阀损坏或失灵：若回油阀弹簧疲劳软化或调整不当，阀座与钢珠的配合面磨损或被脏物卡住而关闭不严时，回油量便明显增加，主油道的油压也会随之下降。

④ The oil return valve is damaged or out of order: if the spring of the oil return valve is fatigued and softened or improperly adjusted, the mating surface of the valve seat and the steel ball is worn or stuck by dirt, and the valve is not closed tightly, the oil return volume will increase significantly, and the oil pressure of the main oil passage will also decrease.

一般来说，如果井下装载机的调压阀设定油压低，机油就不能有效地输送到各润滑部位，从而发生机械故障。如果油压过高，就会增加油耗，给机油泵和润滑部位增加负荷，损坏油路密封件并引发机油泄漏。

Generally speaking, if the set oil pressure of the pressure regulating valve of the underground loader is low, the oil can not be effectively delivered to the lubricating parts, resulting in mechanical failure. If the oil pressure is too high, it will increase the oil consumption, increase the load to the oil pump and lubrication parts, damage the oil seal and cause oil leakage.