The main reason for the burning of the clutch friction plate
(1) The oil temperature is too high
According to the transmission parts surface and the degree of oxidation of the hydraulic oil, determine the hydraulic system oil temperature is too high, and the oil temperature is too high is caused by the hydraulic system hydraulic pump, oil filter, cooler and other components and hydraulic oil, due to In the hydraulic system, too much oil impurities, resulting in oil filter blockage, hydraulic system cycle is blocked, poor cooling and circulation too fast, so that the oil temperature rise; oil temperature and aging of the rubber seal inside the transmission clutch deformation and cracking The performance and life of the clutch are reduced, resulting in poor engagement between the main and the moving parts of the clutch, the slippage between the main and the moving parts, the incomplete clutch separation, and the increased frictional resistance, thereby accelerating the severe wear of the clutch friction lining.
(2) improper use of hydraulic oil
According to the degree of oxidative deterioration of the residual oil of the transmission, it is confirmed that the hydraulic oil is improperly selected. In the hydraulic system, the hydraulic oil acts as a transmission power, and at the same time, it functions as a lubricant and a cooling. If the hydraulic oil is used improperly, it will directly affect the working quality of the hydraulic system. . Practice has proved that 80% of the faults in the hydraulic system are caused by the oxidative deterioration of the hydraulic oil. The valve components in the hydraulic system, such as variable speed pumps, control valves, and lubrication valves, require very precise clearances. The components are provided with resistance holes, control valve holes, lubricant holes, and hydraulic oil inlets. Once the hydraulic oil is oxidized or mixed with a large amount of impurities, these oil holes will be blocked and the flow of hydraulic oil will be hindered, making these components impossible. normal work.
(3) The pressure is too low
If the impurities in the hydraulic oil enter the transmission, it will cause the oil inlet and the oil hole to be blocked. If the impurities in the oil enter the clutch piston and the hydraulic cylinder, the seal ring will be stuck in the hydraulic cylinder and it will not be able to rise outwards. Therefore, the seal between the piston seal ring and the hydraulic cylinder body is not strict, resulting in leakage of pressure oil to reduce the working oil pressure of the clutch, resulting in slippage and ineffective operation. This in turn causes severe wear of the clutch friction lining and poor engagement, and the clutch master The follower plate is not sufficiently lubricated to increase the wear of the Clutch Plate.
2. Preventive measures
In order to extend the service life of the bulldozer transmission clutch, according to our long-term work experience, we must do the following:
(1) Cleaning system
When installing with a new transmission, the hydraulic pump, oil filter, torque converter, cooler, and operating valve of the main hydraulic system should be strictly cleaned. The cleaning fluid is preferably used in the same grade as the torque converter. No. 8 fluid transmission oil is prohibited to use kerosene or diesel oil for cleaning. When cleaning, increase the flow of the cleaning fluid as much as possible so that the mechanical impurities and oil stains in the hydraulic system piping are washed out. After the cleaning is completed, the cleaning solution should be removed in a warm state.
(2) Correct selection of oil products
According to the requirements of the instruction manual, No. 8 hydraulic transmission oil is used for the transmission and chassis hydraulic system. The selected hydraulic oil should have good low temperature fluidity, suitable high temperature viscosity, good thermal oxidation stability and anti-bubble resistance, as well as good resistance to friction and corrosion. It is forbidden to use different brands of hydraulic oil. The oil must be strictly filtered before refueling to prevent mechanical impurities, dust, moisture, emulsions, etc. from intruding into the hydraulic system.
(3) Control system pressure
Before the operation of the machine, the pressure of the hydraulic system shall be strictly inspected, that is, the pressure entering the transmission control valve shall be tested with a pressure gauge, and the standard value of the engagement pressure of the transmission II and III transmission clutch shall be set under the action of the pressure regulator valve (2.5MPa ±0.2MPa), the oil pressure of the I block lock clutch (1.25MPa ± 0.1MPa) and the oil pressure of the lubrication valve (0.1MPa ± 0.025MPa). If the measured clutch pressure is lower than the standard value, first check the variable speed control valve to determine if the clearance between the valve stem and the valve body hole of the variable speed control valve is too large; if the spring force of the pressure regulating valve and the pressure reducing valve is too weak The O-ring on the variable-speed operating valve stem is damaged. If it is damaged, it should be promptly replaced and adjusted. When the decompression spring force of the pressure regulating valve is insufficient, an appropriate-thickness washer can be added to the spring seat to adjust the working oil pressure. And re-installed for testing, if the measured pressure is still lower than the standard value, you must replace the variable speed valve assembly.
(4) Reasonably adjust the meshing gap
Transmission output ends with a pair of helical bevel gears to deliver power to the central axle of the rear axle box. Therefore, the correct degree of engagement has a great influence on the noise, service life and work performance of the whole machine. It should be removed before installation. The large bevel gear on the old host, the new pair of large bevel gears are mounted on the central drive shaft and tightened with bolts; the gear clearance of the bevel gear pair is adjusted through the speed-adjusting gasket to 0.25-0.33mm, and the meshing impression is maintained; This bevel gear must be used as a pair.
(5) Doing maintenance
Maintaining good maintenance and maintenance are important prerequisites for ensuring production safety, giving play to the performance of the transmission clutch, and prolonging its service life. The driver should carry out routine maintenance carefully and strictly, and discover and eliminate minor faults in time to avoid accidents. For newly-manufactured bulldozers or bulldozers that have just undergone major repairs, the oil should be cleaned up after 100 hours of trial operation or operation, and the No. 8 hydraulic transmission oil should be added again. After that, the working oil should be changed every 1000 hours. In daily work, the hydraulic pressure and oil temperature of the hydraulic system should be observed to prevent the oil pressure from being too low and the oil temperature to continue to work. Check the quality of hydraulic oil regularly to keep the hydraulic system and hydraulic oil clean. If any abnormal conditions are found, check the cause and remove the malfunction in time to ensure that the gear clutch of the bulldozer maintains a good working condition.
