Simply mentioning the main relief valve, the first impression of all machine friends is that the valve is very important, and many very difficult failures are caused by the abnormality of the main relief valve, but the specific role may still be very important for everyone. strangeness.
For example, you may have encountered the phenomenon that the whole car is weak and the speed is very slow during the work of the excavator. Sometimes the high-pressure oil pipe often bursts, even after it is replaced with a new one. In fact, the “culprit” of these problems It is the main relief valve!
The main relief valve function:
In the hydraulic system, the main relief valve is used to adjust and limit the system pressure to protect the entire hydraulic system from being damaged. It is installed on the main control valve (distributor) with a cylindrical shape and the top of the main relief valve is available Hexagon socket adjustment, different from other safety valves (overload relief valve), there are two fixed nuts on the top of the main relief valve.
The main relief valve power comes from the hydraulic pump, and then the main relief valve controls the system pressure, and flows to each action cylinder or motor through the main control valve to realize the safety of the entire hydraulic system and the performance of the excavator.
Main relief valve failure:
① The high-pressure tubing often bursts, and the tubing will burst after replacing the new tubing. If this phenomenon occurs, it is necessary to check the main overflow pressure of the excavator.
Solve! Generally, this phenomenon is caused by the pipe burst caused by the excessively high main pressure of the hydraulic system of the excavator, and it can be solved as long as the main relief valve is reduced to the standard pressure.
②The excavator is weak and the speed is very slow during work. This failure phenomenon is a frequent failure of the excavator, usually due to low system pressure, the main overflow valve is blocked by impurities, or the main overflow valve is severely worn. As a result, the flow rate is reduced, and the main overflow pressure is also reduced, and the excavator will be weak and slow.
Solve! Generally, this phenomenon occurs, and it can be disassembled and cleaned slightly, and replaced if it is more serious.
Main relief valve adjustment:
When adjusting, use a wrench to loosen the tightening nut (C) in the picture, turn the adjusting nut (D) clockwise, the pressure increases, and the counterclockwise rotation pressure decreases. After tightening the nut, try again to confirm whether the pressure value after adjustment is normal ( A pressure gauge must be installed during adjustment).
Summarize:
According to the above article, everyone has also found the excavator that has been troubled for a long time, the whole vehicle is weak, the speed is very slow, and the reason for the frequent pipe burst failure. The next step is to check and adjust, but because the main relief valve is in the hydraulic system A very important precision part, so be careful when adjusting!
Post time: Nov-03-2021