The setting pressure of the overload valve is higher than the setting pressure of the main overflow valve. It is more complicated to measure the setting pressure of the valve. If a external force is applied and the method of blocking the oil circuit of the main operation valve is measured at the same time, the pressure of the oil road increases sharply, and the results are very unreliable and can not be used.
The pressure setting of the overload valve must be set under the prescribed flow (usually far less than the amount of oil in the main pump). If the setting pressure of the main overflow valve should be reset to higher than the setting pressure of the overload valve, the main pump needs a lot of hydraulic oil to measure the setting pressure of the overload valve correctly. The valve must be unloaded from the main control valve and tested on the test stand.
The setting pressure of the overload valve is higher than the setting pressure of the main overflow valve. When testing the performance of the overload valve on the excavator, the main overflow valve first overflow the mechanism with the overload valve, such as the bucket, the bucket and the moving arm. Therefore, the overflow pressure of the main overflow valve can be considered to be overloaded if the overflow valve overflow pressure is measured. The performance of the oil valve is normal.
1) detection of overloading valve. According to the above, only the overflow pressure of the main overflow valve is detected when the bucket, the bucket and the arm cylinder are operated. The detection steps and methods of the overflow pressure of the main overflow valve are the same as the main overflow setting pressure.
2) the setting pressure adjustment of overload relief valve. The adjustment of overload pressure setting valve is carried out on the test stand.
A wrench the lock nut with a 17mm open wrench.
B turn the pressure regulating screw with the six angle wrench inside 6mm, increase the pressure when turning clockwise. The screw number and pressure change are shown in Table 1.
C tightened the nut again.
D is re measuring the set pressure on the test bed.
Table 1 change of screw number and pressure
