Abstract: This paper points out seven problems that are easily overlooked in tractor maintenance. These seven problems are analyzed and the correct solutions are proposed.
When the tractor is working, the wear and aging of the parts are inevitable, the technical state is deteriorated, the power is reduced, the fuel consumption is increased, and the faults are constantly appearing. In order to prevent the occurrence of faults, the tractor should be properly and timely maintained to extend the life of the tractor and reduce the cost of use.
In the process of conducting a technical state survey on agricultural tractors, if the maintenance of some parts is found to be not given due attention, it often causes many adverse consequences.
1.Ignore the maintenance of diesel filters
The diesel filter has always played the role of a scavenger. The main function is to filter out the particulate impurities and moisture in the diesel to protect the normal operation of the engine. However, there are also many diesel car drivers who believe that every time the fuel is filled, it will be precipitated for a long time. The impurities and water in the oil are already very clean. Instead, they choose to give up the installation or not to maintain the diesel filter for a long time. This often leads to small losses.
Diesel filters are generally used for 200 to 300 h, and should be cleaned or replaced. Pay attention to the following points:
(1) Air leakage is not allowed in the sealing parts of the air filter assembly. Do not twist when installing the sealing ring. Install it firmly.
(2) Clean the filter element regularly. The paper filter element can not be cleaned with diesel oil. It must be brushed with a soft brush or blown back. The filter element should be replaced if it is broken or blocked. The oil bath type air filter should be replaced with oil regularly, clean the oil pan, and refuel to the appropriate height, not too full or too little.
(3) After the filter has been disassembled and maintained, reassembled and installed on the tractor, the air should be drained.
2. The valve spring will not be replaced for a long time.
Due to the high temperature of the valve spring, it is easy to cause annealing if it is not replaced for a long time, so that the elastic force is insufficient. At the same time, since the valve spring is constantly subjected to the alternating stress, it will be plastically deformed without replacement for a long time, so that the free length is shortened and the elastic force is insufficient. The result of insufficient elasticity will inevitably lead to slow valve operation, close hysteresis, and also cause the valve to be closed tightly, resulting in insufficient cylinder pressure.
3.Ignore the maintenance of small holes
(1) Do not pay attention to the role of starting the nozzle. The carbon deposit in the starting nozzle hole is not removed for a long time, so that the nozzle hole is not smooth or blocked. The function of the starting nozzle is to enable the diesel to be directly injected into the cylinder through the nozzle hole, and first fired in the main combustion chamber to increase the temperature in the cylinder and improve the combustion condition of the mixed gas in the main combustion chamber. Therefore, if the starting nozzle hole is not smooth or blocked, the starting condition is deteriorated, resulting in difficulty in starting.
(2) Fuel tank cap vent. After the hole is blocked, the oil tank is no longer open to the atmosphere, and the upper part of the oil tank will have a negative pressure due to the oil level falling, causing the oil supply to be interrupted; the fuel will evaporate after being heated, causing the pressure in the oil tank to rise, causing oil leakage at the fuel tank switch. This hole cannot be blocked.
(3) Crankcase ventilation holes. When the engine is working, there is always a certain amount of exhaust gas leaking into the crankcase through the piston ring. The oil machine has been used for a long time. As the piston ring of the cylinder liner wears, the clearance increases, the piston ring elasticity decreases, and the exhaust gas leaking into the crankcase will be more. After the venting hole is blocked, the exhaust gas in the crankcase accumulates more, the air pressure in the crankcase rises, the oil leakage will occur, and the high-humidity exhaust gas will be mixed into the oil, which will also accelerate the deterioration of the oil and accelerate the wear of the machine. Therefore, during maintenance Be sure to clear this hole.
(4) Oil pump drain hole. The drain hole on the oil pump is blocked, which will cause a small amount of diesel oil leakage between the push rod and the pipe to enter the fuel injection pump, dilute the lubricating oil in the casing and accelerate the wear of the parts. Therefore, the hole cannot be blocked.
(5) Pump drain hole. If the hole is clogged, the leaked water will not drain out of the pump body and enter the bearing housing, which will accelerate the damage of the bearing. Therefore, the hole must be unblocked during maintenance.
(6) The oil spray hole on the cylinder head cover will not be unblocked for a long time. Because the oil is not clean, etc., it is easy to block or leak the nozzle, which causes the lubrication of the valve, valve guide, rocker arm and other parts, and the wear is too fast, resulting in the valve closing is not strict, the intake is insufficient, the exhaust is not clean. , power loss and other issues.
4.The valve clearance is not adjusted for a long time
When the engine is working, the valve and the valve transmission will expand due to the temperature increase. If the engine without the hydraulic tappet is used, the valve and the valve transmission member have no gap or the gap is too small in the cold state, then it will be in the hot state. The expansion of the valve and its transmission parts causes the valve to be closed tightly, causing the engine to leak during compression and power strokes. Therefore, a normal valve clearance is very necessary. The adjusted valve clearance will also become larger due to the wear of the valve train mechanism, which will reduce the valve lift, cause insufficient inflation, poor exhaust, and will cause abnormal knocking sound. Therefore, after the tractor has been used for a period of time, check and adjust the valve clearance.
5.cooling scale does not clear all year round
If the scale is not removed for many years, the scale will be too thick, and the heat dissipation performance of the machine will deteriorate, which will lead to excessive machine temperature, thinning and deterioration of the oil, deterioration of the mechanical strength of the parts, and early wear of the parts. At the same time, the intake air will be reduced and the power will be reduced; the expansion of the parts will be too large, which will affect its normal technical performance. In severe cases, there will be phenomena such as burning tiles and holding shafts. To this end, before maintenance, the solution prepared with 10 L water, 750 g caustic soda and 250 g kerosene ratio is filled with the cooling system. After the engine runs at medium speed for 5-10 min, the solution is left for 10~12 h (Note: In winter, keep warm or work continuously to prevent freezing. Then, restart the engine at medium speed for 5-10 minutes, release the washing solution, and rinse it carefully with clean water.
6.Ignore the maintenance of the oil filter
Engine lubrication is used for a period of time, mixed with metal chips and other mechanical impurities from the friction of the engine parts and the glue produced by the oil itself. If these impurities enter the lubricating oil path along with the oil, it will accelerate the wear of the engine parts and may also block the oil pipe and the oil passage. In order not to allow these impurities to enter the main oil passage, an organic oil filter is installed in the engine lubricating oil passage. The oil filter should be replaced once at 7500 km. For vehicles that are frequently driven under bad road conditions, the oil should be checked frequently and the time limit for replacing the oil filter should be shortened if necessary.
7.Repeated use of disposable supplies
Paper mats, asbestos mats, cork mats are used for a period of time, and the disassembly process can cause damage and will lose work performance, so it cannot be reused.