Analysis of Loader Hydraulic Transmission System Faults from External Characteristics
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November 27 03:06:14, 2022
zl40 loader hydraulic transmission system work, the gear pump from the oil sump suction low pressure oil, pump out the high pressure oil filtered into the variable speed distribution valve. When the system build pressure (pressure exceeds 1.1mpa), the pressure regulator valve is divided into two, one of them with a pressure of 1.1-1.3mpa through the cut-off valve to the gear distribution valve, and then into the different working hydraulic cylinder according to work needs to achieve â… block, â…± block or reverse gear; the other way through the overflow valve to 0.57mpa struggling to the torque converter to ensure that the torque converter within the hydraulic pressure and flow from the torque converter out of the heat after the low-pressure oil, Back-pressure valve to the size of the clutch and the gear over the gear lubrication. In general, zl40 type loader used 3000h, the hydraulic transmission system will have a variety of failures, have some external performance. Starting from the external characteristics of the aircraft, analysis of the causes of the system failures and exclusion methods. 1 From the hydraulic oil pressure gauge can be found on the fault (1) pressure gauge pointer swing pressure gauge pointer swing in the gear under all conditions, then the air into the air. At this point, lock the oil pump and oil stupid connection tubing to troubleshoot. (2) Each gear pressure deviates from the normal value â‘ The pressure gauge is low for each gear pressure (less than 0.8mpa). Possible causes are as follows: Serious burns on gear pump cause low efficiency; Serious burns on gear pump cause The efficiency is too low; Variable speed valve spring pressure loss of elasticity, the spring seat fracture, the valve stem or accumulator piston stuck, unable to compress the pressure regulating spring; cut off the valve stem stuck in the cut-off position; , Resulting in insufficient oil supply; variable speed distribution valve accumulator seal within the seal damage, so that high and low pressure collusion and so on. â‘¡ block and reverse gear pressure is normal, â…± block pressure low may be due to the reasons: end cover and the box with the â…± block oil hole seal damage or missing equipment (with oil leakage); cover the middle and â…± block Hydraulic cylinder with the Department between the rotation of the oil seal damage, there is leakage; Piston guide pin off, so that high pressure collusion and so on. â‘¢ block and reverse gear pressure is normal, â…° block low pressure may be due to: the hydraulic cylinder and the cylinder into the oil at the junction of the rectangular seal damage or missing equipment; â…° block piston seal damage or cylinder blisters. â‘£ block and â…± block pressure is normal, the reverse pressure is low because of its possible reasons: box wall cracks in the reverse position; reverse piston seal damage; variable speed distribution valve seal damage; variable speed distribution valve seal damage. ⑤ â… block and reverse gear pressure does not go up, â…± block pressure normal its possible reasons are: the cover and the box connecting bolt fracture; the cover and â…° blocked the gap between the hydraulic cylinder is not controlled between 0.3-0.4mm. 2 Malfunctions found from hydraulic oil (1) Large amounts of aluminum scrap in the oil indicate mutual wear and tear between the working wheels of the torque converter; the transmission efficiency is reduced at this time, accompanied by the heating of the working oil. Torque converter should be dismantled to find the wear parts, if necessary, replace the bearing, riveting a turbine cover and so on. (2) The oil contains a large amount of copper flakes, indicating that the main and driven friction plates dry or slip between. Should check the hydraulic oil filling is in place; Check the hydraulic pump pressure is normal, such as normal pressure is the main, driven friction plate improper assembly or deformation, inspection should be replaced. (3) The oil contains a large amount of iron filings, indicating that the clutch is over skidding. At this time, the floor-mounted machine is light-loaded to high-speed and low-speed overloaded. At this time, there is metal friction noise in the transmission, Dead in the wedge tight position; work in this case i block strong work, â…± gear speed does not go up. 3 Malfunctions found from changes in hydraulic oil volume (1) Hydraulic fluid in the transmission is constantly increasing, accompanied by a continuous decrease of hydraulic oil in the hydraulic tank. This situation is generally the work of gear pump or steering pump oil seal damage caused by the oil into the transmission caused. If the replacement of the oil seal, there is still failure, you should check the work of gear pump seal copper sleeve; because copper sleeve damage will result in high-pressure oil will be broken oil seal. Work gear pump gear shaft and the copper gear with the gap between the control 0.025-0.045mm, and does not allow geometric deviation. (2) The amount of hydraulic oil in the transmission is decreasing, and the amount of hydraulic oil in the hydraulic tank is constantly increasing. This situation is generally the gear pump gearbox seal (pg45 × 62 × 12) damage, the hydraulic oil is inhaled by the work of the gear pump. (3) The fluid oil in the transmission is continuously reduced and the oil quantity in the oil pan of the engine is increasing. â‘ The seal ring and the oil seal on the guide ring seat are damaged, causing the hydraulic oil in the torque converter to leak into the flywheel housing. â‘¡ torque converter cover wheel and the impeller between the o-ring damage. â‘¢ torque converter hydraulic return pipe plugging, so that the torque converter back to the oil slowly or without oil, resulting in torque converter seal effect. 4 from the hydraulic oil temperature gauge and engine water temperature table can be found on the fault (1) high oil temperature, water temperature is also high In this case, should first be excluded by water temperature troubleshooting (no longer analyzed here). After the water temperature is normal, if the oil temperature is still high, the following steps can be ruled out. (2) high oil temperature, normal water temperature â‘ check the working medium used is appropriate. Generally 30 # turbine oil or 6 # hydraulic oil. â‘¡ Check the fuel tank level. The oil level is too low or the strainer is clogged, reducing oil supply to the oil circuit and causing the oil temperature to be too high. â‘¢ hydraulic oil radiator blockage, too much sludge between the heat sink, so that poor heat dissipation, leading to increased oil temperature. â‘£ beyond clutch clutching stubborn death. ⑤ gear â…± gear cover 312 bearing assembly too tight. Shaft and bearing with the gap should be controlled between 0.3-0.4mm.