Why does the Komatsu PCA00-2 excavator turn the boom to move in one direction when the boom is raised or the walking joystick is pulled?
To turn the turntable, the turntable distribution valve must not be in a neutral position. This must first be confirmed clearly, and at the same time, the distribution valve should slide normally. Then check again. 0. C. When the pilot control valve does not work, does a large amount of pilot oil enter the two ends of the distribution valve. If the inspection conclusion is normal, it can be determined that the fault is in the rotary flow control valve. Rotary flow control valve A. When there is no control rotation, the A spool is in the middle position, and the relatively zero-pressure hydraulic oil coming out of the Pd port of the jet valve passes through the pump 1 N. After the upper end of the C valve flows through the A valve, and then to the tank. Once the A valve is stuck and the A valve core is not in the middle position, the Pd pressure oil cannot return to the tank, and the oil pressure may rise. Because the A spool is not in the middle position, the openings of the control oil passages of the pump 1, pump 2 and the rotary distribution valve are opened. Move sideways. As a result, the turntable will automatically rotate.
Komatsu PC200-5, PC200-6 type excavation motor arm cylinder piston rod and middle arm cylinder piston rod will appear flange discoloration phenomenon (local oil temperature is too high phenomenon). What is the reason?
Because the PC200-5 and PC200-6 type excavator arm cylinder bottom to the distribution valve, a boom holding valve is installed to prevent the arm movement from automatically lowering. The PC200-6 excavator is also equipped with a middle arm holding valve between the piston rod side of the middle arm cylinder and the distribution valve. Prevent the middle arm from falling automatically.
Because the holding valve is installed in the oil circuit, the hydraulic oil in and out of the cylinder increases resistance. Especially when the back pressure of the spool valve is not well released, the opening of the spool valve is not enough, making the resistance of hydraulic oil flow greater. The greater the resistance, the greater the temperature caused by friction, which causes the local oil temperature to be too high. Komatsu other models do not have this phenomenon.
Komatsu PCA00-3 excavator plunger, plunger body and valve plate work after replacing the new parts for less than half a day, the contact surface of the valve plate and plunger body burns out, why?
There are many reasons, it is possible that the purchased parts are not qualified, and the fuel tank and pipeline are not cleaned well. Excluding the above reasons, the key is that the plunger body and the valve plate are not run in. The newly purchased plunger body and the distribution plate are all in arc surface contact (PC400-3 and PC400-5 types), and the contact surface must be run in before it can be put into normal work. The running-in method can be run-in manually, and then run-in after the machine is installed. The small throttle is used to contract for 4 hours, and the intermediate throttle is used for 4 hours.
Komatsu PC400-3 excavator working pressure is normal. Control pump output pressure and jet valve pressure are also normal. Why do you work weak?
This should carefully check the servo valve. It should be checked from two aspects: first disassemble the valve parts, check the color of the spool and spool, if there is a black part, it means that there is oil in this part, and a new part should be replaced. Secondly, check for abnormal colors. If it is likely that the spool is not adjusted properly, the oil inlet B and the oil outlet C are connected.
Is the overload valve and distribution valve damaged? How to judge?
Judgment method of overload valve failure: remove the plug of the travel distribution valve and replace it with the overload valve. If the boom no longer drops, it means that the overload valve is faulty; the judgment method of the distribution valve failure: pull out the distribution spool, Observe the color. The spool is black. Leakage has occurred.
