What kind of oil is added to the gearbox of the loader? Is the gearbox of the loader a hydraulic coupling?
Dec 20 , 2021
What kind of oil does the loader gearbox add?

Wheel loader for sale have many kinds of gearboxes, and the oil added is different. The gearbox of the loader is equipped with hydraulic oil, the ZF gearbox is equipped with engine oil, and other planetary gearboxes are added with hydraulic transmission oil.

Is the gearbox of the loader a hydraulic coupling?

The gearbox is divided into planetary type and fixed shaft type. Both of them use different gear ratios to change the output speed and torque to achieve the effect of changing the output speed and output torque.

The pump wheel of the torque converter of the loader and the flywheel of the engine are rigidly connected, that is, the input speed of the torque converter and the output speed of the engine are always the same. There will be a variable speed pump in the torque converter of the loader. This

The main function of the pump is to suck oil from the oil pan of the gearbox, supply the transmission oil in the torque converter, and lubricate and cool the gears and clutch plates in the gearbox.

For torque converters, the main parameters are gear ratio and torque ratio. For torque converter manufacturers, they generally provide thousands of revolutions of torque to match the engine with the torque converter.

The working principle of the torque converter is that the pump wheel of the torque converter directly connected to the engine rotates, and the transmission oil in the torque converter is stirred according to a certain law. There is a fixed guide wheel in the middle of the torque converter. When the liquid passes through When guiding the wheel, through various complex changes, it impacts on the output turbine and drives the turbine to rotate to achieve the effect of increasing torque. When the torque is increased, the output speed of the turbine will decrease.

Repair and Maintenance of Damaged Gearshift Mechanism of Loader Transmission

1. Reasons for clutch damage. When the clutch of the power shift transmission is engaged, the pressure of hydraulic oil overcomes the force of the spring to compress the friction plate. With the increase of hydraulic oil pressure, the friction plate comes into contact with the metal disc and is gradually compressed, so that the clutch transfers the flywheel power to the transmission input shaft smoothly. Every time a gear is shifted, the friction plate will rub against the steel plate, and the heat generated will be dissipated by the coolant. When the friction plate and the steel plate become thinner, in order to make them fully engaged, more hydraulic oil is needed. The engine must be further accelerated, and the friction plate slipping time on the steel plate will also be prolonged, and the resulting frictional heat will also be greater. To increase the temperature of the hydraulic oil, when it reaches a temperature sufficient to change the performance of the seals in the transmission, the transmission will leak internally. The internal leakage continues to cause the increase of heat from two aspects: the high-pressure oil leaks through the damaged seal, causing the oil temperature to continue to rise; due to the oil leakage, the hydraulic pump is bound to deliver more oil to ensure that the clutch is engaged. The required pressure enables the clutch to be fully engaged, which also requires the engine to continue to accelerate, so that the hydraulic pump produces greater flow. Such a vicious circle will eventually cause the clutch to overheat or burn, until it completely fails.

2. Detection of clutch piston tightness. When the loader is weak or the oil temperature is too high, it is necessary to judge whether the clutch piston is not tightly sealed or the oil pressure is insufficient. However, it is sometimes difficult to determine which cause the failure by conventional detection methods, especially In the case of no power, it is even more difficult to inspect the seal rings of the assembled transmission assembly. At this time, a pneumatic valve can be used for testing. First, remove the transmission control valve (for the assembled transmission, before installing the control valve), and then in turn pass the oil holes of the transmission with a gas of 0.6 to 0.8MPa. If a certain hole is filled with gas, you will hear " "Boom" and no air leakage or little air leakage. Imported metering pump indicates that the seal between the corresponding clutch piston and cylinder barrel is good; if you can’t hear the sound of the piston pressing the friction plate and the sound of air leakage Larger, it means that the seal between the clutch piston and the cylinder is ineffective, and the seal should be replaced.

3. Prevention of loader transmission failure The bearings and gear pairs of the power shift transmission are vulnerable parts, so the loader transmission should be checked and maintained regularly. The maintenance interval of a typical foreign transmission is 5000-10000h. According to my country's national conditions, it is recommended to check the wear of the clutch every 2500 to 5000h, and catch abnormal signals at any time. Since the power shift transmission is unlikely to fail quickly, it can usually continue to be used for 750-1000h after the first signs of wear on the friction linings. During this period, frequent inspections and maintenance, and timely replacement of friction plates, seals and individual bearings can avoid damage to undamaged parts (such as steel plates, gears, shafts, hydraulic cylinders, and most bearings, etc.).

4. The following abnormal conditions often occur before the clutch fails: (l) Although the machine can still work, the oil in the transmission has long been deteriorated, the viscosity has dropped and contains metal impurities, so it should be more frequent before the recommended oil change interval. Analyze the transmission oil sample. Because the clutch wear is a sign of the expansion of the transmission failure, if metal impurities enter the gear pair or jam the gears so that they cannot be centered, other components in the transmission will be crushed if the machine does not stop. (2) Decreased shifting performance is a sign of clutch damage. When the clutch starts to slip, the machine will rush forward even if it accelerates steadily. At this time, it should be shut down for maintenance. (3) The clutch operating oil level drops. When the machine must accelerate to make the clutch engage, it means that the clutch has been excessively worn or the seal has failed. Therefore, the wear of the clutch can be determined by measuring the oil pressure of the loader transmission and observing whether the oil temperature rises. At the same time, the oil quality should be analyzed. If iron or chromium particles appear in the oil, it indicates that the gear pair has begun to wear. In summary, if the seals and friction plates are replaced before the clutch fails, the maintenance cost will be 30% lower than the maintenance after the clutch fails. Similarly, if repairs are carried out before the planetary row or gear pair fails, the cost will be 2/3 lower than repairing a completely damaged transmission.
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