Excavator maintenance and overhaul are necessary for excavators, just as people rely on meals. Good maintenance and overhaul methods will also increase the service life of the excavator and promote the coordination ability of the excavator operation. In the same way, poor maintenance and overhaul will cause great harm to the excavator. So, what taboos and misconceptions exist in the maintenance and overhaul of excavators?
1. Avoid only adding but not changing the oil
Engine oil is indispensable in the application of diesel engines. The key is to moisturize, refrigerate, and purify.
Therefore, many drivers pay attention to check the remaining oil of the grease and add it according to the specifications, but they ignore the regular inspection of the grease quality and the replacement of the oil that has already deteriorated. As a result, the hydraulic components of some diesel engines are always in Running in a badly moisturized natural environment will accelerate the damage of hydraulic components. In the whole process of diesel engine operation, a lot of wastes (soot, carbon deposits and grease stains, etc. converted into gasoline and diesel ethanol combustion) are entered into the engine oil. For new or repaired mechanical equipment, there will be a large amount of residue after trial operation. If you only need to replace it and deliver it eagerly, it is very easy to cause accidents such as tile burning and axle holding.
2. Avoid installing new cylinder liners and pistons without matching
When removing and replacing cylinder liners and pistons, many people ignore the certain dimensional tolerances of cylinder liners and pistons. Although the two are all standard parts, it is still necessary to match the size specifications to prevent the gap from being too large and jeopardizing startup.
In addition, if each cylinder is equipped with cylinder liners and pistons of the same sequence number, attention should be paid to the inspection of the cylinder plug gap before installation. In order to ensure the standardization of the assembly line, a test should be carried out before installation to prevent the installation of fake and inferior 名媛直播. .
3. Avoid checking the plunger stroke capacity
In the irony of the plunger diesel pump, many maintenance workers did not pay attention to checking the stroke capacity of the plunger. To put it plainly, the stroke capacity of the plunger refers to the amount of movement that the plunger can move up again after the top of the camshaft on the engine camshaft is higher than all dead points. Interruption of the oil supply in the adjustment may cause the accident. Just after the start time, the stroke capacity is often checked, because the stroke capacity of the plunger is related to the damage of the plunger and sleeve specifications.
After the plunger and sleeve specifications are damaged, the plunger must be strengthened for a while before the oil supply can be interrupted, which may cause an accident, and then interrupt the oil supply, which may cause the accident to occur. . When the adjusting anchor bolts are unscrewed or the thicker adjusting protective layer pads or gaskets are used, the least part of the plunger is displaced, which reduces the stroke capacity of the plunger.
Therefore, when repairing and adjusting the diesel pump, the stroke capacity should be checked first to determine whether the diesel pump still allows adjustment. When checking, the following different methods should be selected according to the different structure of the diesel pump:
a. Rotate the engine camshaft, and after the plunger top is higher than all dead points, remove the oil outlet valve and high pressure gate valve and measure with a depth vernier.
b. After the plunger is pushed to the top dead center, use a screwdriver to pry up the yellow spring seat of the plunger to raise the plunger to the highest peak. Then insert a thickness gauge between the lower plan view of the plunger and the tappet adjustment anchor bolt to measure. The standard stroke capacity of the plunger is about 1.5mm, and the ultimate stroke capacity after damage should not be less than 0.5mm.
4. Avoid inaccurate measurement of cylinder gap
When measuring the cylinder gap, it is impossible to measure the orientation of the piston pin hole vertically bisecting the piston journal, and measure it in other orientations. The structural characteristics of the aluminum alloy piston are small in the upper part and larger in the lower part. It is a cone, and the cross section of the journal is elliptical, so the cylinder gaps above the circle are not the same. When measuring, it is required to take the gap of the elliptical minor axis as the standard, that is, to measure the gap of the piston pin hole perpendicular to the piston journal. That measurement is more convenient and accurate, and in repeated motions, the orientation of the piston pin hole that is vertically bisected by the piston journal is greatly damaged due to the effect of the side working pressure. Therefore, when measuring the cylinder gap, the piston should be bisected vertically on the piston journal Orientation measurement of pin holes.
5. It is not suitable to sand and polish the piston pin
When someone replaces the bearing bush, in order to increase the contact area between the bearing bush and the crankshaft, they use emery cloth instead of scraping bushes. This method is extremely undesirable in actual maintenance, because the abrasive grains on the emery cloth are harder, but the bearing alloy is softer, so the sand grains are easily embedded in the alloy during grinding, and the wear of the journal will be accelerated when the diesel engine is working. Shorten the life of the crankshaft.
6. Avoid over-tightening the anchor bolts
Many people feel that the tighter the anchor bolts are, the less likely they are to loosen, and the safer they are. In fact, it is an incorrect idea. Not only excavators, but many positions of industrial equipment actually have certain regulations for anchor bolt torque. In other words, there are certain regulations for the tightness of anchor bolts in many positions, and it cannot be too loose or too tight. Too tight and easy to break, will cause common failures.
7. Avoid adding cold water to the water tank when the temperature is too high
Overloading of the engine, poor heat dissipation or lack of water in the water tank will cause the water tank to boil. If cold water is immediately added at this time, it will cause the cylinder head and cylinder block to burst. Therefore, once the water tank is found to be boiling during use, emergency measures should be taken to stop the operation to allow the diesel engine cooling water to cool down by itself.
The above are the 7 aspects of daily maintenance that we often forget or don’t pay attention to. We hope that in the future, the operators can pay attention to the maintenance of the excavator. After all, correct maintenance is an effective means to extend the service life. One of the prerequisites for improving work efficiency.
