Revo classroom: excavator cold car normal hot car slow to teach you to solve!

In the whole digging machine circle, there is a kind of fault that can make the old and new drivers equally helpless and helpless. That is, the excavator is normal when the cold car or the newly started work, but after a period of hot work, the excavator moves weakly and the speed gradually slows down. So what is the cause of the failure, and how to troubleshoot?

Revo excavator

1. Hydraulic oil replacement and maintenance

Special reminder, relative to the car of the age, the car with the breaker for a long time must change the hydraulic oil on time, many of the faults are caused by the hydraulic oil, of course, the hydraulic oil is thicker when the car is cold, so the pressure when the car is cold Basically, the flow rate can be guaranteed. Once the temperature of the hydraulic oil rises to about 60 degrees, the operation starts slowly. First, look at the cleanliness of the hydraulic oil. The oil return filter and the cleanliness of the oil filter are checked and judged.

Brick home reminder: the hydraulic oil commonly used in excavators is No. 46. The bigger the grade, the greater the viscosity. The lower the grade, the high temperature is very easy to occur. The higher the viscosity of the grade will affect the speed! Komatsu excavators now also recommend Komatsu TO10 special transmission oil.

2, control the oil circuit failure

When the hot car is slow, check the pilot pressure first. If the pressure is too low (minimum 3.2MPA), then check if the gear pump (Komatsu self-pressure reducing valve) is leaking. Is the pilot filter (filter) miscellaneous? Causing blockages. If the pilot pressure is not enough, the main control valve working device stem cannot be fully opened, resulting in slow speed and no force.

3, the main pump failure

The hot-vehicle slow-fault main pump is also one of the reasons. When checking the pressure flow of the main pump, the reaction after adjustment is not large or basically no effect, then the main pump should be removed, the regulator wears, the servo plunger wears, and the distribution plate Wear, the plunger and cylinder wear, the swashplate wear, and the wear and tear in these places will cause the hot car pressure flow to be low.

4, electromagnetic proportional pressure reducing valve failure

There is also a component that affects the main pump pressure and flow rate is an electromagnetic proportional pressure reducing valve (each brand is called different, the function is basically the same), the electromagnetic proportional pressure reducing valve function is to obtain the signal current provided by CP U computer version, so that the pilot pressure is carried out. The proportional pressure is reduced to control the output oil of the pump. If there is a problem, the flow pressure of the pump will also be too low or the card will not adjust at a certain position.

5, the main control valve failure

The main control valve internal leakage is the main cause of the slow speed of the hot car. The main reason is that the daily maintenance is not in place. The hydraulic oil is not checked or replaced in time. The frequent use of the crusher is also the main cause of the main control valve. The pressure of the crusher is improperly adjusted. The hydraulic pressure is not replaced in time. The oil will cause impact wear on the valve stem of the main control valve, the main relief valve, and the oil port relief valve, and finally cause the internal leakage to be slow.

The above points are the main reason for the slow speed of the excavator after the hot car, whether it is the maintenance master or the excavator boss must first find the root cause of the fault and then "the right medicine." (This article is from Revo)