When the bulldozer is working, the temperature of parts and components in each part is within a certain range. If the temperature of a part suddenly rises, shut down and stop the operation immediately for troubleshooting. Taking a sd7k hydrostatic bulldozer as an example, the temperature of the transfer case is abnormal, and its shell temperature is about 90 ℃. To analyze the cause of heating and troubleshooting.

　　Transfer case structure

　　The purpose of the transfer case is to distribute the power output from the flywheel of the engine to the working pump, (left and right) travel pump, make-up oil pump and pilot pump through its driving gear, passive gear and idler gear. The lubricating oil from the lubricating pump is delivered to the meshing parts of each bearing and gear of the transfer case for lubrication after being regulated by the pressure regulating valve (the regulated pressure is 0.14MPa). The heat generated by the normal operation of the transfer case is dissipated through its shell, thus forming the balance and stability of the transfer case lubricating oil temperature.

　　Troubleshooting

　　Under the heavy load working condition of the machine, we observe that the engine is running normally, the transfer case is running normally and there is no abnormal noise, and the lubricating pressure of the transfer case is normal after the field test, which means that there is no abnormal damage to the internal gear and bearing of the transfer case. According to the structural analysis of the transfer case and its lubrication system, under the normal working condition of the transfer case, the heat source is mainly the heat generated by the operation of its gears and bearings, while the heat generated by the hydraulic pump and the pressure regulating valve is less, which is unlikely to cause a sharp rise in the temperature of the lubricating oil.

　　Further analysis shows that the volume of the transfer case shell is small, and the speed of the built-in flywheel is 1700-2100r / min. If the transfer case is filled with too much lubricating oil, under the high-speed rotation of the flywheel, the internal gear of the transfer case will stir the lubricating oil in the case, which may cause the loss of engine power and the heating of the lubricating oil.

　　Check the dipstick and find that the lubricating oil filled in the transfer case housing has greatly exceeded the upper limit of the dipstick. Put the lubricating oil in the transfer case into the calibrated range of the dipstick, start the engine and test it under the heavy load working condition of the bulldozer for a period of time, the transfer case temperature is normal, and the fault phenomenon disappears.

　　According to the regulations, the transfer case can be filled with 15-17l oil for lubrication, and the oil level is just within the calibration range of the dipstick, at this time, the oil just submerges the edge of the flywheel ring gear. If the lubricating oil is filled too much, it will not only produce a large power loss, but also cause a sharp increase in the temperature of the lubricating oil in a very short time.

　　In a word, if you have any problems, you should stop and shut down in time to check and contact the after-sales service for troubleshooting.