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DEMAG company produces the H95 type hydraulic excavator, bucket capacity, high production efficiency, and form a complete set of 32 tons of dump truck when using better effect, its electric control system and hydraulic crawler tension device is easy to operate and maintenance.

1, pump points dynamic gear box channeling in hydraulic oil (1) failure phenomenon pump points dynamic gear box into hydraulic oil, and from the respirator overflow. (2) the cause analysis for three main pump were installed in the pump points dynamic gear box, according to the system working principle analysis, channeling oil site may have two: one is the pump points dynamic gear lubrication pump in the hydraulic oil intrusion, namely due to long time work, lubricating oil pump skeleton oil seal damage or aging, leading to the main pump 1 within the hydraulic oil into lubricating oil pump, the cycle into the pump points dynamic gear box, time from the respirator overflow; The second is the main pump and pump points dynamic gear box joint channeling oil, namely the main pump skeleton oil seal damage or aging, make the main pump in the high pressure hydraulic oil pump points directly into dynamic gear box, and since the respirator overflow. Main pump seal drive or axial movement can also lead to the hydraulic oil into lubricating system. The reasons are: oil seal installation clearance, pump shaft driving produce rotation; And the pump connecting spline in bearing wear, leading to pump shaft runout, make the oil seal inner ring and outer deformation with clearance increases and produce oil seal drive and axial movement; The oil pressure of the long time effect, make oil seal produce axial movement; The hardening of oil seal and the diameter of axle with wear is intensified, leading to fit clearance increases. (3) troubleshooting preempt and disassemble pump points dynamic gear lubrication pump oil seal, check the oil seal and shaft fit are good, whether have damage or aging phenomenon; Check installation oil seal trunnion place to have obvious wear, and then judge whether for fault location; Then check that

the main pump seal. Disassemble the three main pump, respectively take out oil seal and check whether the inner edge of the aging or damage; Oil seal spring is failure, install oil seal in the axial and radial have traces of wear and tear to judge whether the for fault position. Solution to the problem: change regularly oil seal; Regular cleaning and maintenance of hydraulic system heat dissipation device, regular detection system pressure, to ensure the system normal heat; By changing the pump shaft or shaft radial wear parts of chrome plating to repair. 2, the engine is normal, but the work device without action (1) failure phenomenon engine work is normal, but the work device but without any action. (2) the reason analysis in pilot pump discharge, and even damage; Pilot loop pressure reducing valve jammed, in normally open position; Pilot circuit electromagnetic valve main circuit break; Pilot oil circuit main pipe burst; Due to the circuit has fault cause electric liquid control switch valve Y61 the application of electronic controls made possible failure; Engine and pump points between dynamic gear box of elastic coupling damage. (3) troubleshooting for fault, for three main pump not may also damage, so need not to test the system pressure. Should check the oil level of hydraulic system, insufficient add; Such as hydraulic oil enough, can check pilot main lines, the damage should be repaired or replaced. Then, check the pilot oil circuit electromagnetic valve main circuit for open circuit and electric hydraulic control switch valve Y61 circuit; If the electric control part breaks down, should first will be the electro-hydraulic control switch in the fluid control part of the failure, and test movable arm movement situation. Finally, check the pilot pump internal damage and reducing valve clean; After the repair of commissioning. Pilot loop setting pressure is 3.5 MPa, when circuit pressure when more than 3.5 MPa pressure reducing valve and automatic pressure relief. Can the 6 MPa pressure gauge connected to the M5 place, test pilot loop pressure, when the pressure reducing valve when not through four make loop pressure is 3.5 MPa. And debugging. 3, track no tension or without walking motion (1) failure phenomenon track no tension or no walk movement, the other normal action. (2) cause analysis to tension oil circuit electromagnetic valve Y16 circuit break; Tension pressure limiting valve damping hole ÎŚ 2 mm jam or pressure low; Tension control circuit and a check valve of any two failure, can't set up the pressure; Tension accumulator failure, etc., which can lead to track no tension action. Travel brake friction plate burned, deformation, lead to brake lock; Tension cylinder oil leakage serious or walk motor damage; Walk operated valve jammed, etc, all can make the machine without walking motion. (3) troubleshooting first, check to tension oil circuit of electromagnetic valve Y16 related circuit and electromagnetic valve itself is normal or not, the damage should be repaired or replaced, make track tension action returned to normal. Or should be through the test tension hydraulic cylinder M18.3 and M18.4 place pressure, judge tension pressure limiting valve damping hole ÎŚ 2 mm is blocked. At the same time, check the tension loop and a check valve wear (wear serious when can lead to set up the system pressure not to rise) and tension accumulator work, the damage should be repaired or replaced. Then, through the decomposition, check the tension hydraulic cylinder or walk motor can also be found fault reason, if cylinder no serious wear, can replace the seal or change of assembly parts, also can open with the other side of the hydraulic cylinder or motor to test. If the step walk under the pedal moment, gear ring have instant action, in the circuit normal circumstances, can judgment is brake friction plate for burned deformation and lead to the side brake lock, replace the friction plate can debugging; Otherwise should check operated valve or

the plunger is jammed. In addition, brake tube or pipe joint leakage can also lead to the failure occurred, only need to change tubing or flange seal can place. 4, movable arm action is slow (1) failure phenomenon movable arm action is slow, the rest of the normal movement. (2) the cause analysis for movable arm hydraulic oil two pump pressure low; Whip the main control valve set pressure is too low, Movable arm operated valve card die, and not open; Movable arm cylinder seal damage, the drain or leaked seriously. (3) troubleshooting to two pieces of pressure gauge and mpa were up in M11, M12 pressure point test the two groups of main valve pressure, if the pressure is too low, should check whether the main valve body loose, again by adjusting the main relief valve pressure gauge pointer refers to that in 31 mpa or so. In the debugging process, if the pressure is always less than 30 mpa or so, it should be test for movable arm hydraulic oil two main pump pressure point M19.2 and M19.3 pressure, the pressure at 30 mpa or so, and then setting main relief valve pressure in 31 mpa or so. Otherwise, will check the operation valve core in stroke in sports, such as whether agile valve core card death or the oil leaked, the valve should be clean or replace the parts of the seal. If a fault is still cannot rule out, and finally should overhaul movable arm hydraulic cylinder, replace the seal, solve the hydraulic cylinder inside leaking or leaked, fault and can be ruled out. 5, some Suggestions (1) find gear box respirator have oil spill over, want to change in time the corresponding pump oil seal, and stop overhaul, best one-time debugging, or repeated repair will waste a lot of lubricating oil and the mechanic. (2) in the repair process, must be kept clean and sanitary, hydraulic components shall not be cotton and interfusion hydraulic system, lead to valve core card dead and so on the new fault, troubleshooting, must first check the gear oil and hydraulic oil oil level, is insufficient to add. (3) must be in open the hydraulic oil tank switch valve, and then start the engine or may be due to the cylinder oil and cause gear box or main pump damage, even scrapped. (4) eliminate hydraulic system fault, the remove tubing or may have a high pressure oil spurt, should first will engine flameout, the cylinder pressure, and then for troubleshooting.

DEMAGH95 type hydraulic excavator four troubleshooting