bulldozer lack of gear is a common failure. The main reasons for this include several aspects. First, there is a leak in the shift control valve. Second, there is no proper seal between the shift control valve and the clutch oil passage. Third, the shift clutch piston is not properly sealed. Fourth, the friction plate 5. Excessive friction of the steel plate. Fifth, the planetary gear reducer is faulty.

　　diagnosis method

　　First, use a pressure gauge to measure the pressure value of different gears. If the detected pressure value is slightly smaller than the standard value, it may be due to the sealing problem of the shift control valve. If it is found to be damaged after inspection, it must be replaced in time. After the replacement is completed, the test is performed again. When the detected pressure value is still less than For standard values, the inner core of the transmission valve is tested again. If it needs to be replaced, replace it in time. If the monitored values are normal, and then further detect the cause of the failure, you can complete the test by carrying out the compression test of the transmission. The operation method is: disassemble the control valve and inflate the compressed air of a specific pressure into the oil passage. If the piston driven by air at this time produces a crisp sound under the action of the spring and returns to the position at the same time, it indicates that the gears of the speed change device are properly sealed. If there is no sound from the clutch device of any gear, the surface piston seal is not good, and the shape may change. If there is a jam, it should be restored to normal in time, and the condition of the friction plates and steel plates should be checked at the same time. If the friction value is too large, the parts should be replaced in time.

　　1: Bulldozer flameout and solution

　　If the bulldozer is in operation, the warning light will give a warning sound, and the equipment needs to be stopped in time to conduct a comprehensive inspection. If the engine fuel tank liquid level is within the normal value range, it means that the equipment is working normally and there is no abnormal phenomenon. If the operation continues, the equipment is turned off and cannot be restarted. Remove the fuel tank. If the neck is severely damaged and the bearing bush melts, it indicates that the flywheel installation was unreasonable and unbalanced during the repair process.

　　2: Causes of flywheel imbalance

　　The function of the flywheel is to increase the rotational inertia of the engine to keep it rotating at a constant speed. In addition, it is extremely beneficial to the startup of the equipment. Promote the piston to pass through the top dead center, so that the engine overcomes the overload problem. Before installation, the flywheel must be properly calibrated. If an imbalance occurs during operation, recalibrate to avoid severe vibrations during operation, resulting in a burnt tile accident, and to break the flywheel components. During the installation process, when the degree of unbalance exceeds the standard allowable range, under the action of external load, it may cause the crankshaft to oscillate violently, resulting in lubrication failure, increased friction, and rapid local temperature rise, which causes the alloy to melt and cause burning Tile accident.

　　3: Measures to avoid unbalance of flywheel

　　First, because the unbalance degree of the flywheel exceeds the allowable range of the standard, after the maintenance of the equipment, an unbalance test must be carried out. After the flywheel assembly is completed, check the amount of runout of the plane to the crankshaft, whether it meets the specifications. Second, there are no cracks on the flywheel, keep the surface flat, and have sufficient smoothness flatness error, the plane error is less than 0.1 mm, to ensure flatness, the size is less than 1.2 mm, to avoid the flywheel thickness does not meet the requirements. Third, the working surface of the flywheel is in a wave state, the depth is less than 0.5 mm, and it is kept flat on the lathe. The depth of the wave groove is not more than 0.5 mm. Two annular grooves are not allowed to avoid burrs. The full runout of the end surface of the crankshaft by the flywheel plane exceeds the stipulation, and a gasket is added between the flywheel coupling disk and the flywheel, and mechanical adjustment is not allowed. Fourth, from the process point of view, if the flywheel casting is not annealed, it may cause an increase in the offset, resulting in an unbalanced flywheel. In the casting process, if there is a large internal stress in the web, which is not annealed, it may be due to local defects and uneven thickness, or cracks may occur under the impact of external forces. If the flywheel is used after processing, balancing, and installation, local stress or uneven thickness may occur when the stress disappears, resulting in a change in the amount of deformation around the web, causing the center of mass to move, and the flywheel to become unbalanced. Annealing treatment.

　　4: Failure analysis of bulldozer without steering

　　If the bulldozer pulls any one of the rotation directions during use, the left and right levers are simultaneously pulled, and the bulldozer still advances straight ahead. It was initially determined that the steering system was malfunctioning. Then conduct a detailed inspection of the following issues. First, check whether the steering system guarantees that the bulldozer can still run in a straight line, check the tie rod and spring equipment, and ensure that the connection is good, the gap between the rods is reasonable, and the fault occurs on the steering hydraulic circuit. If the steering pump and transfer case are kept connected, the mechanical energy can be converted into hydraulic energy, the oil is sucked out from the rear axle box, filtered through the coarse filtration equipment and fine filtration equipment, enters the diverter valve, and passes the diverter valve according to the determination The ratio is allocated to the steering valve and the brake circuit. The operating pressure of the steering valve is the standard value, and this pressure value needs to be realized by the sequential valve. The oil of the sequence valve enters the circuit and mixes with the oil liquid inside, and enters the torque converter again. Under normal circumstances, if the handle is not turned, the pressure oil flowing to the left or right side of the diverter valve is closed into the steering valve, and will not flow to the clutch device to achieve oil supply. The steering clutch device is in an engaged state, to the left and right A small hole is provided on each side to continuously supply oil. If the steering valve works, the separation of the clutch equipment can be achieved, so that the bulldozer stops working. When troubleshooting, the oil pressure is measured by fine filtration equipment to ensure that the steering pump is running well, and the pressure oil pressure can be measured. Check the diverter valve, sequence valve and steering valve. If the chip inside the sequence valve is stuck, it means that it cannot turn flexibly.

　　5: Common clutch faults and troubleshooting methods

　　Clutch equipment slipping: If the distance between the friction plates is too large, the gap can be adjusted in time. When the distance between the friction plates is greater than one-third of the thickness, it needs to be replaced in time. If the friction lining of the clutch device is contaminated with oil, it can be washed or replaced.

　　The clutch equipment cannot be completely separated: steel sheet warping, or bearing bite, can be handled by replacement and adjustment.

　　Clutch equipment shakes: If the bolt is loose or the arc is too large, you can adjust it by tightening it.

　　6: The joystick is too heavy: When the adjustment of the whole disk is unreasonable and the amount of oil is insufficient, the adjustment disk can be loosened and the oil amount can be adjusted.

　　In summary, crawler bulldozers are widely used in industrial production and have a positive significance for the development of production. It is necessary to do equipment maintenance and maintenance to avoid equipment failures during operation. Replace with new ones to prevent equipment from running abnormally due to component aging and affecting production. Technical personnel should understand the working principle of the equipment. When the equipment fails, the fault location should be judged in time and repaired reasonably.