Excavator maintenance often encounter 9 problems, The real reason is actually like this!
1. After checking that the orifice is not blocked, why is the safety valve pressure still no adjusted?
A: Most that :is due to the fact that the cone valve and the valve seat are not tightly closed, so that the oil pressure in the C chamber cannot be established.
2. What should I pay attention to when grinding the end face of the gear?
A: It is necessary to grind with a high-precision grinding machine after the gear pump gear wears, And find a responsible master for example, the grinder table should be absolutely clean and do not allow dust on the platform.It will offset the ground plane from the vertical line of the bearing hole because the table is slightly unclean.
3. How do you know that the ground plane of the ground gear & bearing hole have changed?
A: It can only be found when assembling the gear pump, because the clearance of the end face is very small, generally about 0.05mm. If the end face is perpendicular to the bearing hole, The gear shaft cannot move after the pump is assembled. If the locking screw is loosened a little, but it still does not turn smoothly, then the gear pump is removed and the end face is scratched. Because the end face plane is not perpendicular to the bearing hole.
4. What should I pay attention to when assembling the gear pump?
1.The wear of the pump casing will be more in the oil inlet cavity. The contact point of the 180° line can be reversed If the pump casing is symmetrical. It is necessary to add a little oil and then rotate it by hand after the pump is assembled. The hand will feels smooth.
2.Must be replaced at the same time. Because of the wear of the pump end face, mainly because the bearing clearance is too large, causing the gear to sway during rotation.
3.Reuse,For the passive gear, the two ends cannot be exchanged, and the mark is to be taken when removing. Because the gear will wear on one side. The driving tooth is integral with the rotating shaft and cannot be turned over; the passive tooth is turned over to make the two gears mesh.
5. While the track can only move forward and not back. What is the reason?
A: It is caused by the overload overflow spool in the travel motor being stuck. The travel motor is safe for the protection system. Two overload relief valves are installed in the system. The system pressure is lost if one of the overload relief valve spools is stuck in the overflow position.
6. The crawler is slow on the side, The crawler can get up quickly if you do a swing at the same time. Why?
A: This fault will occur on many excavators. This is because the flow rate supplied to the travel motor plunger pump is insufficient. When the excavator does another action at the same time, It is equivalent to adding another plunger pump flow. The flow rate of the two pumps will be merged in the Komatsu PC200-2 excavator control valve, and the Komatsu PC200-3 to PC200-6 excavator will merge on the linear travel valve. However, the flow rate of the plunger pump is insufficient, not necessarily because the pump is damaged, and most of them are caused by the fact that the flow control valve is not adjusted.
7. When operating the two joysticks at the same time, The engine speed will drop in an instant or even turn off when the shovel starts. Why?
A: It is more common. This is mainly due to problems with the variable mechanism of the plunger pump. The plunger pump still has a large flow rate when the machine is idling.
8. The traveling oil motor has just been repaired. The crawler will go faster when the small throttle is used. It will not go When the throttle is too big . Why?
A: Because the distribution plate is ground during maintenance & amount of grinding is too much, So the pressing force of the distribution plate and the plane of the cylinder is not enough. The oil pressure is small, and there is no leakage between the plane and the plane when the throttle is small; The oil pressure increases when the throttle is large , The overflow occurs between the planes, which causes the crawler belt to be unable to move when the throttle is large. The remedy can be applied to the spring. The butterfly spring can be added if it is a butterfly spring.
9. What is pulling the excavator to walk the joystick and feel heavy (almost unmovable).why?
A: The travel distribution valve is different from other distribution valves. The travel distribution valves of most machines are not hydraulically controlled, but are pulled directly by hand through mechanical levers. Because the machine is outdated, or the distribution slide valve has worn out, the clearance between the travel slide valve and the hole becomes larger, and the high-pressure oil leaks fro