Hydraulic excavator repair and maintenance Excavator is a main machine in engineering construction. At the same time, it can also be used as a multi-functional operation machine. For example, it can complete a variety of engineering operations such as lifting, grabbing, ditch cleaning, slope repair, crushing, and demolition. The excavator has become one of the main engineering construction machines. What do you know about excavator maintenance?
1. One track can only move forward, not backward?
The overload overflow valve element in the traveling motor and engine is stuck. To protect the safety of the system, the traveling motor is equipped with two overload relief valves in the system. If one of the overload relief valve cores is stuck in the overflow position, the system pressure will be lost.
2. One side of the track moves very slowly, but if you do a rotation at the same time, the track can get up quickly. Why?
This fault can occur on many excavators. This is because the flow to the plunger pump of the travel motor is insufficient. When the excavator performs another action at the same time, it is equal to the flow of another plunger pump. The flow of the two pumps will converge in the control valve of Komatsu 200-2 excavator, and Komatsu 200-3 excavator to PC200-6 excavator will converge on the straight travel valve.
The insufficient flow of the plunger pump is not necessarily due to the damage of the pump, but mostly due to the failure to adjust the flow control valve.
3. Pulling the excavator's walking handle makes me feel heavy. Why?
Travel distribution valve is different from other distribution valves. The travel distribution valve of most machines is not hydraulically controlled, but directly pulled by hand through a mechanical pull rod. As the machine is old or the distribution slide valve has been worn, the fitting clearance between the travel slide valve and the hole becomes larger. High pressure oil will leak from the oil passage through the slide valve clearance to the end with spring. There is a spring cover outside the spring, which forms high pressure inside the cover. As a result, when the distribution valve moves to the side with spring, the control lever is very heavy (lighter in the other direction).
4. When the excavator starts up by operating the traveling levers of the two tracks at the same time, the engine speed will drop instantly, or even stop. What is the reason?
This fault is common. This is mainly due to the problem of the variable mechanism of the plunger pump. When the machine is idling, the plunger pump still has a large flow.
5. The traveling oil motor has just been repaired. The track moves faster when the accelerator is small, but it will not move when the accelerator is large. What is the remedy?
The traveling oil motor has just been repaired. When the accelerator is small, the crawler will move faster, but when the accelerator is large, it will not. What is the reason and what remedies are available? This is because the valve plate has been grinded and the grinding amount is too much during maintenance, so that the compression force between the valve plate and the cylinder surface is not enough. When the throttle is small, the oil pressure is small, and there is no leakage between the planes; The oil pressure increases when the throttle is high, and overflow occurs between the planes, which makes the track unable to move when the throttle is high. The remedy can be to add a gasket to the spring. If it is a butterfly spring, an additional butterfly spring can be added.
