Common faults of excavators
Disassembling the variable mechanism found that the pin of the variable piston fork dropped
Clean the assembly unit, assemble the main pump, and then replace all hydraulic oil. After the error, the engine is basically normal, and the driver calls to inform and excavate the machine to repair ( wéixiu) The walking was off course, the right was faster than the left. This phenomenon did not occur before repair, but it only occurred after repair. Therefore, it is speculated that this repair is related. Checking the information shows that the oil supply of the front pump is walking on the left, and the oil supply of the rear pump is walking on the right. Right now is faster than left, it may be caused by high rear pump pressure or rear pump flow (unit: cubic meter per second) is greater than the front pump. Analysis (Analyse) believes that the rear pump has just replaced five new plungers, the new The plunger clearance is small, and the front pump is still the old one. The oil pressure generated by the new plunger is higher than that of the old plunger, while the leakage is small and the flow is large.
This makes the oil output of the front and rear pumps different, which causes the phenomenon that the left and right wheel speeds are different. After discussion it was decided not to disassemble the main hydraulic pump (Hydraulicpumps), but to adjust the flow of the front and rear pumps to solve this problem. To this end, adjust the adjusting bolts on the rear pump adjusting valve (material: cast iron, cast steel, stainless steel, etc.) Rotate it 90 degrees inward and reduce the rear pump flow. Turn the adjusting bolt on the front pump adjusting valve 90 degrees outward to increase the flow of the front pump, and then tighten the fastening bolt on the outer ring of the adjusting bolt. After restarting, test driving, the phenomenon of walking deflection was obviously improved. Then use the aforementioned method to adjust the flow of the front and rear pumps, and test run. Under normal conditions, the possible causes of abnormal noise around the main pump are as follows: insufficient hydraulic oil causes the main pump to empty. Air is mixed in the road. Blocking (dǔsè) of the oil absorption filter (filter material: glass fiber filter paper, chemical fiber filter paper, etc.) causes the main pump to be empty. The main pump is worn inside. Excavator repair, excavator repair, repair excavator, repair excavator
As a result, the main pump works abnormally. The fault identification process is as follows: first adjust the working device to the oil level detection position, check that the oil level of the hydraulic tank (TheFuelTank) is within the normal level of the oil standard, and initially remove (remove) the pump is empty or mixed in the oil circuit. Possibility of air. Start the engine to revolve the machine and hold the front and rear pump output pipes of the main pump by hand. The test result is that the vibration of the output high-pressure oil pipe of the rear pump is significantly larger than that of the front pump. The severe vibration makes the hand feel unable to hold it. Check the output oil pressure of the main pump. Observation of the oil pressure gauge on the instrument panel shows that the front pump oil pressure is significantly higher than the rear pump, 33MPa and 26MPa, respectively. Check the oil return filter in the oil return tank (function: filter impurities, etc.), there is no obvious metal powder on it. Fumble with your hands at the bottom of the tank.
Excavator Engine Smoke | Excavator Engine Burning Oil | Excavator Engine Exhaust Gas | Excavator Engine Water Temperature High Since I started Doosan-type for a year, Excavator Repair (wéixiu) | Excavator Repair | Excavator憋 Car | Maintenance of the excavator, I often worry that he will have a fault in the circuit system, but it has not appeared in this year, and the excavator that I opened before has such a problem. I also understand the doorway, so It is also a great help for me to maintain the Doosan-type excavator. Doosan is actually a good excavator, with good performance and quality, as well as excellent after-sales service. Excavator engine emits black smoke | Excavator engine burns oil | Excavator engine exhaust gas is large | Excavator engine water temperature is high What will you do when you really encounter a fault in the Electriccircuit system?
Maybe some people will be helpless, and some people will know how to solve it. Let me analyze how I do it below. The boom descends too fast, and "nods" when the boom is raised. A "nod" failure is usually a damage to the load check valve at the control valve inlet, but no problems have been found afterwards. Combined with the system principle (Maxim) diagram analysis: the failure is a check valve failure between the boom control valve and its acceleration valve. Confirmed after disassembly. Turning around and walking right suddenly disappeared within a few minutes. ation), check that the fuel tank (TheFuelTank) returns a large amount of copper (chemical formula Cu) iron powder. Copper and iron powder also appeared in the front pump casing. The front pump is severely damaged. Suddenly, the whole vehicle moves slowly and the speed is 1/5 of the standard operating speed. The repair of the old car for the excavator's pot repair is to repair the assembly, assembly and parts removed from the car during the repair.
After repairing, they are all replaced in the original car. The engine is working properly. The fault was damage to the engine speed (RotationalSpeed). Suddenly, the whole car acted as a “car,” and it was found that the variable solenoid valve PCV of the rear pump did not work. The reason was that the connection between the solenoid valve and the computer board was often shaken by the machine, and the wiring harness plug was loose, resulting in disconnection. The whole machine is slow and the hydraulic pump has abnormal noise. After inspection, there was a large amount of paper dust on the strainer at the pump suction port of the hydraulic oil tank. After cleaning (liquidate), the whole machine works normally. After about 30 minutes of normal work, turning and right walking, and boom and stick movements are extremely slow. Other actions are normal. After exchanging the main pump outlet tubing, the bucket and left-hand movements are extremely slow, indicating that the fault is on the front pump or its variable organization. After cleaning the valves of the variable mechanism, the whole machine works normally. Suddenly the bucket and left walking were extremely slow.
After exchanging the main pump's outlet tubing, turning and right walking, as well as the movement of the boom and stick are extremely slow. Checking with the separation method confirmed that the fault was on the variable mechanism of the rear pump. Disassembling the variable mechanism found that the pin of the variable piston fork dropped. Normal after reinstallation. After the engine is running for about 2 to 3 minutes, left walking becomes slower. The inspection revealed that the engine was muffled at no load and seemed to be working under load. After testing the hydraulic pump outlet pressure, immediately after the engine is started, the no-load pressure of the front pump is 1.3 MPa, and the no-load pressure of the rear pump is 1. Z MPa. However, after 2 to 3 minutes, the no-load pressure of the front pump was 1.3 MPa, and the no-load pressure of the rear pump was 30 MPa. According to the analysis of the schematic diagram: After the pressure changes, the actuators have no action, and the pressure generated by the system can only come from the action of the backup valve. After removing the pilot control tube at both ends of the backup valve, the fault disappeared. The second mobile phone has been used for 3 years.
Since the purchase of the machine, I found that the retracting lever and lifting boom are slow during work, and the others are normal. After inspection, the tie-rod half-flow (unit: cubic meter per second) valve was artificially changed, and it worked normally after the original system was restored. Tracks are weak and have no low gear. The excavator's inability to introduce the hydraulic system of the excavator is systematic, specific. The structure and working principle of the pump, valve, motor, hydraulic cylinder and auxiliary components in the hydraulic system are introduced in detail, and the disassembly, repair and installation methods of each component are described in detail. In each model, the electronic control system and fault diagnosis and elimination method are also introduced systematically. The basic contents of Komatsu excavator maintenance include: equipment maintenance, equipment inspection and equipment repair. After replacing the seal of the central swivel joint, the fault remains. The travel speed solenoid valve (magnetvalve) found that the spool was stuck due to dirt in the oil. Normal after cleaning. Suddenly left walking forward without moving, the rest of the movement is normal.
After inspection, the overload valve of the left travel motor was cushioned with dirt by the dirt, resulting in weak forward movement. Large excavator maintenance technical service agency. The company has always served the majority of excavator owners with the basic concept of "sincerity as the foundation and faith first". Tongda Excavator Maintenance Co., Ltd. relies on domestic leading inspection, debugging, maintenance equipment and experienced maintenance technicians. It is called "the most professional excavator repair and after-sales center in the west". Xinzhou Komatsu excavator maintenance service station calls China's current research and application of condition monitoring and fault diagnosis is not extensive enough, in-depth, comprehensive maintenance support, the level of informatization is still low, and maintenance research and development and verification technology is still immature The research on the basic problems of software-intensive mechanical equipment, such as failure and repair mechanisms, corrosion and protection mechanisms, has just begun. The development of Shantui bulldozer maintenance technology is still facing huge challenges. There are particularly large gaps.