Loader Gearbox maintenance:
Loader power shift gearbox hydraulic multi-disc wet clutch shift shift, each shift is composed of 3-10 friction plates and corresponding pressure plate, hydraulic cylinder and so on. When operating the shift lever in the variable speed control valve, the pressure oil flows into the corresponding hydraulic cylinder through the variable speed control valve, and pushes the piston to compress the active plate and the driven plate, so as to achieve the purpose of transferring power. In practical use, often wait until the machine can not work properly before maintenance, resulting in the loss of optimal maintenance time, shorten the service life of the transmission. This paper analyzes the cause of clutch damage of power shift transmission. In order to prolong the service life of power shift transmission, this paper introduces a method of detecting the sealing of clutch piston and measures to prevent transmission failure. 1. Causes of clutch damage Power shift gearbox when the clutch engages, the pressure of hydraulic oil resists the force of the spring to compress the Friction Plate. As the hydraulic oil pressure increases, the friction plate comes into contact with the metal plate and gradually compresses, allowing the clutch to smoothly transfer flywheel power to the transmission input shaft. With each shift, the disc rubs against the steel and the coolant dissipates the heat generated. When the friction plate and steel plate thinner, more of the hydraulic oil is needed to fully engage, engine need to be further accelerated, friction plate on the steel friction time also increased, the resulting friction heat more, makes the hydraulic oil temperature, when to produce enough to change the transmission when the temperature of the sealing performance, transmission tends to leak. Internal leakage continues to increase heat in two ways: high-pressure oil leaks through damaged seals, making the oil temperature continue to rise; As a result of the oil leak, the hydraulic pump may deliver more oil to ensure that the pressure required to fully engage the clutch also requires that the engine continue to accelerate to produce more flow to the hydraulic pump. This vicious cycle eventually causes the clutch to overheat or burn out until it fails completely. 2. Clutch piston sealing test When the loader is weak or the oil temperature is too high, it is necessary to determine whether the clutch piston is not tightly sealed or the pressure is insufficient. However, it is sometimes difficult to determine the cause of routine testing. In particular, it is more difficult to check the seals on an assembled Transmission Assembly without power. At this point, a pressure valve can be used for testing. First remove the gearbox control valve (the control valve should be installed before assembling the gearbox), and then open 0.6-0.8mpa of air to each oil hole in the gearbox. If one of the holes through the gas, "bang" and no leakage or leakage sound is very small, the seal between the clutch piston and the cylinder well is intact; If you can't hear the piston compression friction plate and the larger leakage sound, it indicates that the seal between the clutch piston and the cylinder is faulty, and the seal should be replaced. 3. Prevention of gearbox failure: the bearings and gears of the gearbox are vulnerable parts, and the gearbox should be checked and maintained regularly. The typical foreign transmission maintenance interval is 5000 to 10000h. According to China's national conditions, it is suggested that the clutch wear should be checked every 2500-5000h, and abnormal conditions should be captured at any time. Since the power-shift transmission does not fail quickly, debris first appears on the friction plate and can usually continue to be used for 750-1000h. During this period, regular inspection and maintenance, and timely replacement of friction plates, seals and individual bearings. Clutch in failure before often appear the following abnormalities: (1) although the machine can still work, but the oil in the gearbox has long deteriorated, viscosity reduced, containing metal impurities. Check the transmission oil sample before the recommended oil change interval. Because clutch wear is a sign of an expanding gearbox failure, if metal impurities get into the gears or jam them out of center, they can break other parts of the gearbox if not stopped. (2) The decline of shift performance is a sign of clutch damage. When the clutch starts to slip, the machine will charge forward even if the acceleration is smooth. At this time should be shut down maintenance. (3) The clutch control oil level drops, when the machine must accelerate the clutch engagement, indicating that the clutch has excessive wear or seal failure phenomenon. Therefore, measuring the transmission oil pressure, observing the oil temperature rise, can judge the clutch wear situation. The oil should also be analyzed. If iron or chromium particles are present in the oil, it indicates that the gear pair has begun to wear. In summary, if the seals and friction plates are replaced before clutch failure, the repair cost will be 30% lower than after clutch failure.
