Preventive Measures for Burning Loss of Diesel Engine Bearings

Early damage to sliding bearings is much more common than bearing burnout, so it is important to prevent early damage to sliding bearings. Correct maintenance of sliding bearings is an effective way to reduce early bearing damage and a reliable guarantee for extending bearing life. Therefore, in the daily maintenance and repair of the engine, it is necessary to pay attention to the appearance and shape of the alloy surface, back, end and edge corners of the bearing. measures to improve the working conditions of the bearing, and pay attention to the prevention of early damage to the sliding bearing. ①Strictly measure the coaxiality and roundness of the main bearing hole of the diesel engine body. For the measurement of the coaxiality of the main bearing hole of the body, the coaxiality of the diesel engine body must be measured accurately, and the runout of the crankshaft must be measured at the same time, so as to select the thickness of the bearing bush, so that the oil-lubricating gap is consistent in each axis. . If the diesel engine has been subjected to rolling tiles, flying cars, etc., the coaxiality of the main bearing hole of the body must be tested before assembly. The roundness and cylindricity are also required. If it exceeds the limit, it is disabled. If it is within the limit, use the grinding method (that is, apply an appropriate amount of red powder on the bearing bush, install it into the crankshaft and rotate it, and then remove the bearing cover to check the bearing bush, and if there are hard spots convex After scraping the outgoing part, measure the change in size to ensure the reliability of use. ②Improve the maintenance and assembly quality of the bearing, strictly control the pass rate of the connecting rod on the car, improve the hinge quality of the bearing, and ensure that the back of the bearing is smooth and free Spots and positioning bumps are intact; the self-opening amount is 0.5-1.5mm, which can ensure that the bearing bush fits closely with the bearing seat hole by its own elastic force after assembly; the parallelism and distortion of the new and old connecting rods are required to be measured. The unqualified connecting rod is forbidden to get on the car; each end of the upper and lower bearing shells installed in the bearing seat should be 30-50mm higher than the plane of the bearing seat, and the higher amount can ensure that the bearing cap bolts are tightened according to the specified torque. It is closely matched with the bearing seat to generate sufficient frictional self-locking force, the bearing will not loosen, the heat dissipation effect is good, and the bearing ablation and wear are prevented; , The matching clearance of the bearing and the journal should meet the requirements without scraping. In addition, pay attention to check the processing quality of the crankshaft journal and the bearing during assembly, and strictly implement the repair process specifications to prevent improper installation due to improper installation methods. And the torque of the bearing bolts is uneven or does not meet the regulations, resulting in bending deformation and stress concentration, resulting in early damage of the bearing. Sampling inspection of the purchased new bearing pads. Focus on the thickness difference of the bearing pads and the size of the free opening, and visually inspect the surface. Quality. After cleaning and testing the old bearing bushes in good condition, the original body, original crankshaft, original bearing bushes, and in-situ assembly and use are implemented to ensure the cleanliness of diesel engine assembly and oil. Improve the performance of cleaning equipment, strictly control the cleaning quality, and improve The cleanliness of each part of the diesel engine. At the same time, purify the assembly site environment and make the cylinder liner dust cover, so that the cleanliness of the diesel engine assembly has been significantly improved. ③ Reasonable selection and filling of lubricating oil. In the process of use, the oil film surface tension should be selected It can effectively prevent bearing cavitation; the viscosity grade of lubricating oil cannot be increased arbitrarily, so as not to increase the coking tendency of the bearing; the oil level of the engine lubricating oil Must be within the standard range, lubricating oil and refueling tools must be clean to prevent the entry of any dirt and water, while ensuring the sealing effect of all parts of the engine. Pay attention to regular inspection and replacement of lubricating oil; the place where lubricating oil is filled should be free of pollution, No sandstorm to prevent the intrusion of all pollutants; Lubricants of different quality, different viscosity grades and different types of use are not allowed to be mixed, and the precipitation time before lubricating oil filling should generally not be less than 48h. ④ Correct use and maintenance of the engine. When installing bearings , the moving surface of the shaft and bearing should be coated with clean oil of the specified grade. After the engine bearing is installed, the fuel switch should be turned off before the initial start, and the engine should be driven to idle several times with the starter. Turn on and open the fuel switch, put the accelerator to the low-medium speed position, start the engine and observe the operation. The high-speed operation time cannot exceed 5min. Do a good job in the running-in operation of the new engine and the engine during the running-in period after the overhaul. During the running-in period, it is forbidden to work under the condition of sudden increase and decrease of load and high speed for a long time; after the engine finishes working at full load for a long time, it cannot be stopped immediately, and the engine must be left empty. It can be stopped after running at medium and low speed for 15 minutes, otherwise the internal heat will not be dissipated. Strictly control the starting temperature of the locomotive and increase the fuel supply time for starting the locomotive.