Carter Excavator Repair
Caterpillar CAT320 excavator troubleshooting technology
Therefore, the pilot oil pressure should be checked first and determined to be normal. Use a DC clamp meter (set in the milliamp block) to clamp a single proportional solenoid valve. On the wire, place the mode switch under heavy load, start the car, do it, and do it. The clamp meter has no current indication. The voltage at the input terminal is about 24V, which is positive. Often; measuring the proportional solenoid valve resistance is ∞, indicating the proportional solenoid valve. The coil is open. Check the proportional solenoid valve. Found the lead seal. The wire has been fatigued and broken. Re-weld the seal and put it back into the test drive. Do it. The DC clamp meter will read between 250 and 600mA during operation. The function is normal, the fault is removed, and the failure phenomenon Ⅱ is slow, but the vehicle is not stuck, and the engine load is very light. The speed of the excavator is determined by the flow rate. The amount of force is determined by the pressure output by the main pump. For this reason, obstacles need to be checked from both flow and pressure control.
Check with fault I method, the DC clamp meter reads 280 ~. 600mA. The output pressure of the proportional solenoid valve is 15 ～, indicating that the proportional control system and the pilot oil circuit are working normally. The output pressures of the upper and lower main pumps are about 26 MPa, which is too low. Upon inquiry, the aircraft was previously transferred. The main relief valve is broken. The pressure cannot be adjusted. Raise the engine to the rated speed. Adjust the main relief valve 48 in the middle of the multi-way valve group. As shown in Figure 1, screw the adjusting lever to the end. Only rose to 27MPa. Explain that there is indeed a problem with the main relief valve, remove it. Clean the lower main relief valve and screw the upper piston chamber of the relief valve inward. 4 turns, then replace the main relief valve and adjust. The pressure rises. Will Lord. The pump pressure was adjusted to 32 MPa. At this point the digging force came up, but the whole car. The movement is still very slow.
CAT320 Excavator Common Troubleshooting Technology, Dai Wei. (Liaoning Liaozhong County Water Conservancy Bureau Construction Engineering Company, Liaozhong 110200, Liaoning, China), [Chinese Classification Number] TU621 [Document Identification Code] B [Article Number] 1001-1366 (2006), Examine and repair of common failures of CAT320 excavators DAI Wei, Figure 1 Multi-way control valve group, 1-main relief valve 48; 2-flow regulating valve 33; 3-flow regulating valve 38; and then adjust the power regulator of the main pump up and down. Adjust the screws. Turn it in and the power will increase. Go back and the power will decrease. Due to the hydraulic pressure, power = flow × pressure. When the pressure is constant.
Increase power. The system traffic will increase, and the speed of the entire vehicle will become faster. It will be adjusted for the first time. Screw the whole screw in 1/4 turn. No change in speed, twist 1/2 further. Circle, the speed still does not change, indicating that the fault is in multi-channel control, troubleshooting, 58 2006 (03) Construction MECHANIZATION, the flow regulating valve in the valve, the flow adjustment of the upper and lower main pumps in Figure 1, throttle valves 38 and 33 Installed on the bottom and right sides of the left and right ends of the multi-channel control group. Remove the flow control valve and find that the paper cores in the valve core are clogged with oil filters. Open the hydraulic tank cover and the oil return filter has been sucked. Broken, two big holes, immediately drain the oil, clean the hydraulic system, change the filter. Device, refuel. Clean the flow regulating valve, put it back, and try again.
The car is very fast, but the engine feels awkward. Then slowly back out the adjustment screw of the power and rate adjuster until the speed is moderate, but you don't get stuck. The fault was completely eliminated, and the CAT320 excavator appeared to have slow movements, engine crashes, and obstacles. Under normal circumstances of the pilot oil circuit, proportional solenoid valves are mostly used. The failure of the solenoid valve control circuit should focus on checking the output of the controller, and whether there is overlap, short circuit and open circuit in the line and proportional solenoid valve coils. The speed of the computer excavator and the size of the digging force vary with the outside world and the size of the load. When the proportional control circuit fails, the output of the pump cannot be automatically adjusted, and the speed of the engine is continuously reduced until The flameout and severe car jamming phenomenon, the diagnosis and elimination of this fault is suitable for all computer excavators. Such as slow motion, weak digging, but the engine does not get stuck.
If there is a fault, the pressure and flow are mostly under the condition that the pilot oil circuit is normal. The volume adjustment system is faulty. First, adjust the main relief valve and adjust the pressure of the main pump to 30 to 32 MPa. Then adjust the flow. If not, use the power regulator to adjust the flow to the required range. Adjustable, flow regulating valve, flow regulating valve is adjusted by adding or removing gaskets. Yes, increasing the shim flow increases, decreasing the shim flow decreases, such as. There is a flow tester. Connect the flow sensor to each single pump back. Circuit, and raise the engine to the rated speed. Under no-load conditions, the flow rate is adjusted to 240L / min. Without a flow tester. Can only rely on. How fast you do it. Based on experience and feeling to adjust the flow, the author has repaired several CAT320 computer excavators using the above method, and achieved good results.
[references].  Zhu Qiping. Manual for Imported Engineering Machinery Maintenance [M]. Shenyang :, Liaoning Science and Technology Press. 2001.  Liang Jie and Wang Huijun. Engineering machinery electrical and electronic control devices, [M]. Beijing: People's Communications Press. 1999. , (Editor Wu Rongsheng). [Received Date], [Author's Introduction] Dai Wei (1961-), male, Shenyang, Liaoning, senior engineer, deputy, manager. Engaged in water conservancy project management. 130 Government Road, Liaozhong County. [Brief introduction of the author] Li Jianbin (1962-), born in Zhaoxian, Hebei. General manager. The national first-level construction division is engaged in the construction management of tunnel engineering. Luoyang City, No. 3 Dongbei Lingyuan East Road. (Continued from page 49), the large uniaxial compressive strength is between 60 and 150 MPa.
It is more suitable for mining. Use double shield TBM for construction. In conclusion 5, double shield TBM has two driving modes. Strong adaptability, suitable for both hard rock and soft rock; when corresponding measures are taken, it can. Adapt to fault fracture zone, high in-situ stress, rock burst, karst and other bad, geological, and has the advantages of factory three-dimensional construction, flow operation, the construction progress is 3 to 6 times the drilling and blasting method. Long, large railway tunnels greater than 5km. When the geological conditions are suitable, after full technical and economic justification, double shield TBM can be used for construction, and the construction period will be increased before it will produce huge economic and social benefits,  Wang Mengshu. Li Dianyu. Zhang Jingjian, etc. Rock Tunnel Boring Machine, (TBM) Construction and Engineering Examples [M]. Beijing: China Railway Publishing House, Press, 2004. .