Hydraulic excavator repair and maintenance Excavator is a major machine in engineering construction. At the same time, it can also be used as a multi-functional working machine, such as it can complete a variety of engineering operations such as lifting, grabbing, trench cleaning, slope repair, crushing, demolition, etc., the excavator has now become one of the main machinery for engineering construction. What do you know about hydraulic maintenance knowledge of excavators?
1. One track can only move forward but not back?
The overload spool in the travel motor and engine is stuck. To protect the safety of the system, two overload relief valves are installed in the system. If one of the overload relief valve spools is stuck in the overflow position, the system pressure will be lost.
2. The crawler moves slowly on one side, but if you make a swing motion at the same time, the crawler can get faster, why?
This failure occurs on many excavators. This is because the flow rate to the plunger pump of the travel motor is insufficient. When the excavator performs another action at the same time, it is equivalent to adding another plunger pump flow. The flow rates of the two pumps will be merged in the Komatsu 200-2 excavator control valve, and Komatsu 200-3 to PC200-6 excavator will be merged on the straight travel valve.
The plunger pump's insufficient flow rate is not necessarily the pump is damaged. Most of them are caused by the flow control valve not being adjusted.
3. Why is it so heavy to pull the excavator walking handle?
Walking distribution valve is different from other distribution valves. The walking 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 spool has worn out, the clearance between the walking spool and the hole becomes larger, high-pressure oil will leak from the oil passage through the spool clearance to the end with the spring, and there is a spring cover outside the spring The cover is tightly closed to make high pressure inside the cover, which causes the lever to be very heavy when the distribution valve is to be displaced towards the spring side (it is lighter in the other direction).
4. When the excavator is started by operating the walking operation levers of two crawlers at the same time, the engine speed will drop instantaneously, or even turn off, is it and the reason?
This failure is more common. This is mainly a problem with the variable mechanism of the plunger pump. When the machine is idling, the plunger pump still has a large flow rate.
5. The walking oil motor has just been repaired. The track will move faster when the throttle is small, but it will not walk when the throttle is high. What is the remedy?
The walking oil motor has just been repaired, the crawler will go faster when the throttle is small, but it will not walk when the throttle is high. What are the reasons and what are the remedies?
This is because the valve plate has been ground during maintenance and the amount of grinding is too much, so that the pressure force between the valve plate and the cylinder plane is not enough. When the throttle is small, the oil pressure is small, and it is not easy to cause leakage between the planes; when the throttle is large, the oil pressure increases, and the overflow occurs between the planes, which causes the crawler to not move when the throttle is large. The remedy can be to add a gasket on the spring, if it is a butterfly spring, you can add an additional butterfly spring.
