Daily inspection work is an important link to ensure that the hydraulic excavator can maintain efficient operation for a long time, especially for the self-employed, doing a good job in the daily inspection work can effectively reduce the maintenance cost.
First around the mechanical turn two laps check appearance and mechanical chassis, and rotary support whether there is oil outflow, then check the deceleration brake device and the crawler bolt fasteners, the tighten the tightening, the timely replacement, if it is a wheeled excavator will need to check whether the tire is strange, and the stability of the pressure.
Check whether the excavator bucket teeth have large wear, it is understood that the wear of the bucket teeth will greatly increase the resistance in the construction process, which will seriously affect the work efficiency and increase the wear of equipment parts.
Check whether the bucket rod and the oil cylinder have cracks or oil leakage phenomenon. Check the battery electrolyte to avoid being below the low level line.
Air filter element is an important part to prevent a large amount of dusty air from entering the excavator, and should be checked and cleaned frequently.
Check often the fuel oil, lubricating oil, hydraulic oil, coolant, etc., whether you need to add, and it is best to choose the oil according to the requirements of the instructions, and keep clean.
post-firing check
1. Whether the whistle and all the instruments are in good condition.
2. Starting status, noise and exhaust color of the engine.
3. Whether there is any engine oil, fuel oil and coolant leakage.
Management of fuel oil
Diesel oil with different grades shall be selected according to different ambient temperature (see Table 1); diesel oil shall not be mixed with impurities, dust and water, otherwise the fuel pump will wear prematurely; the high paraffin and sulfur content in inferior fuel will damage the engine; the fuel tank shall fill up the fuel to prevent the water wall of the fuel tank; before daily operation; after the engine fuel is exhausted or the filter element is replaced, discharge air in the road.
Management of other oils
Other oils include engine oil, hydraulic oil, gear oil, etc.; different grades and different grades of oil cannot be mixed; different kinds of excavator oil add additives with chemical or physical effects in the production process; keep the oil clean, prevent debris (water, dust, particles, etc.); select the oil label according to the environmental temperature and use. High ambient temperature, should choose oil with high viscosity, low ambient temperature should choose oil with low viscosity; gear oil viscosity is relatively large, to adapt to a large transmission load, hydraulic oil viscosity is relatively small, to reduce liquid flow resistance.
1. Reasonable selection of hydraulic oil
(1) Hydraulic oil viscosity
The principle for determining the viscosity of the hydraulic oil is to keep the hydraulic oil viscosity (for the operating temperature and efficiency of the hydraulic loop) in the optimal range (16-36x10-6m ㎡ / s); 1000X10-6m ㎡ / s corresponding to the lowest ambient temperature; and 10X10-6m ㎡ / s corresponding to the maximum leakage oil temperature of 90℃.
(2) Viscosity index (VI)
This index directly reflects the change of oil viscosity with temperature, (that is, the viscosity index of the oil), which indicates that the viscosity of the oil changes less with temperature; otherwise, it is larger. The viscosity index of the anti-wear hydraulic oil of the well-known foreign manufacturers (such as Mobil, Shell, etc.) is VI 110, and the viscosity index of the domestic advanced anti-wear hydraulic oil is about VI=95. The viscosity index of high viscosity index hydraulic oil (HV) and multi-stage engine oil produced abroad is VI> 140. This point for the use of large imported hydraulic excavator and using domestic hydraulic oil (or the engine oil for hydraulic oil) users should be paid special attention to. The decrease of viscosity index will reduce the ambient temperature range of the oil. If it is not used, the relevant information should be inquired to the oil manufacturer, the use range of the oil should be adjusted appropriately, and the relevant set value of the equipment (such as the limit temperature) should be changed if necessary.
(3) Other comprehensive performance
Due to the high working pressure of modern large hydraulic excavator hydraulic system (32MPa), allowing the highest working oil temperature of hydraulic oil is higher (about 90℃), so in order to ensure that the hydraulic system can work in the normal oil cycle, for the system selected oil lubrication, oxidation stability, wear resistance, rust corrosion, emulsification resistance, bubble resistance, shear stability and extreme pressure load has good quality.
2. Good hydraulic oil heat dissipation system
For large hydraulic excavator hydraulic oil cooling system (more specifically should be the hydraulic oil temperature control system), although the specific way is different, but the basic idea is the same, can make the hydraulic oil temperature in continuous operation balance in the ideal range, and can make the hydraulic system in cold work can heat up quickly (to the oil normal working temperature range). Under the condition of using qualified hydraulic oil, when the hydraulic oil is overheating, the inspection steps of the hydraulic oil cooling temperature control system are as follows:
(1) Whether the hydraulic oil radiator is blocked with dirt, resulting in the decline of heat dissipation efficiency, and clean the radiator when necessary.
(2) Check the actual working pressure of the system at the fan speed under extreme conditions to determine whether the hydraulic parts of the circuit are faulty, and whether the oil temperature sensor or the control circuit is working normally. At this time, the fan speed and system working pressure shall be maximum; otherwise, the system parameters shall be adjusted or the damaged components replaced.
3. Check of the relevant hydraulic parameters in the system
There are two main control modes of working pump of large hydraulic excavator: ultimate load adjustment (GLR) with load loss (CUT) and load induction adjustment (OFF function). The function of CUT-OFF is that when the working pressure of the system reaches the adjusted value, the oblique disc Angle of the variable pump is reduced, so that the pump can only maintain the "residual" flow state required to maintain the pressure, so as to avoid overheating caused by the overflow of the overflow valve. For this purpose, the system parameters are matched to keep the set value of the CUT-OFF valve below that of the primary pressure valve in the circuit; otherwise, the opening of the primary pressure valve will cause overflow overheating.
At the same time, check whether the secondary valve works normally, this work must be carried out in strict accordance with the technical requirements, and the relevant parameters of the system should be adjusted when necessary.
4. Exclude abnormal internal leakage
It mainly refers to the abnormal leakage caused by the card bite of the directional valve and pressure valve caused by the pollution of the hydraulic oil of the system. Check the method: measure the pressure, check the function, or listen to whether there is abnormal noise (throttle closing caused by the valve is not strict) or touch check whether the temperature is locally too high.
5. Prevent the volume efficiency of the components from decreasing
Abnormal wear and normal wear, should be paid attention to. The former may occur in a very short time, and can be judged by checking the quality of the oil and the function of the system (such as whether the action of the execution components is normal, whether the speed drops, etc.); the latter should follow certain rules, investigate comprehensively, and take timely measures.
Lubricating oil lipid management
The use of lubricating oil (butter) can reduce the wear of the moving surface and prevent noise. When storing grease, avoid dust, sand, water and other impurities; recommend lithium base grease G2-L1 with good wear resistance and suitable for heavy load conditions; remove the old oil as far as possible to prevent sand adhesion.
