Construction machinery oil refers to the special lubricating oil specially used for large mechanical equipment such as large excavators, loaders, hoists, forklifts, cranes, concrete mixers and rollers. It mainly includes four categories and more than ten varieties of diesel supercharged engine oil for construction machinery, anti-wear hydraulic oil for construction machinery, heavy-duty gear oil and hydraulic transmission oil. This article will briefly introduce the use standards of diesel engine oil, transmission system hydraulic oil and heavy-duty gear oil for reference only.
1. Engine oil or diesel oil
Construction machinery often works at high speed and high load. The role of engine oil is to deliver lubricating oil to the friction surface of moving parts, so as to realize the functions of lubrication, sealing, cleaning, cooling, hydraulic pressure, cushioning and rust prevention.
The quality level shall be selected according to the recommendations of the internal combustion engine manufacturer, the mechanical load and thermal load of the diesel engine, the severity of working conditions and other factors. Viscosity grade can be selected according to:
1) Ambient temperature: if it is often in a high temperature environment, high viscosity oil products, such as 15w-40 or even 20W-50, should be selected. If it is used in northern winter, oil products with better low temperature performance should be selected.
2) Load: high viscosity oil shall be selected for construction machinery with large tonnage, heavy load and continuous high-speed operation, so as to ensure sufficient oil film strength at high temperature; Small mechanical equipment with small load and mild working conditions can use diesel engine oil with low viscosity.
3) New and old equipment: the matching clearance of new equipment is small, and low viscosity oil can be selected. The old equipment has a certain degree of wear and large matching clearance. It is necessary to use oil with greater viscosity to meet better sealing requirements. Therefore, the oil viscosity of old equipment is generally higher.
2. Transmission system hydraulic oil
Hydraulic transmission takes liquid as the working medium and uses liquid kinetic energy to transfer energy. The impeller converts the speed and torque input by the power machine (internal combustion engine, motor, turbine, etc.) and drives the working part of the machine through the output shaft. The liquid interacts with the impellers installed on the input shaft, output shaft and shell to produce the change of momentum moment, so as to transfer energy.
Hydraulic transmission oil is not only the force transmission medium of hydraulic transmission, but also the hydraulic control oil for shift actuators, such as wet shift clutch, shift brake and various control valves in automatic shift hydraulic system. It also provides lubrication and cooling for bearings and gears in torque converter and gear transmission. Therefore, hydraulic transmission oil is a highly demanding oil, which is directly related to the reliability, transmission efficiency and service life of hydraulic components. The commonly used brands of hydraulic transmission oil for construction machinery include No. 6, No. 8 and other products.
3. Heavy duty gear oil
The gear transmission device of construction machinery mainly includes transmission device, steering gear, gearbox of front and rear drive axle, universal joint needle roller bearing and other parts. The importance of transmission in power system is second only to engine. The stepped transmission is the most widely used. It adopts gear transmission and has several fixed transmission ratios.
In order to make the transmission work stably and effectively for a long time, appropriate vehicle gear oil must be added to reduce the friction and wear of the gear, transmit the heat generated by the friction surface and prevent corrosion and corrosion.
The performance characteristics of vehicle gear oil mainly lie in its small kinematic viscosity, excellent extreme pressure and wear resistance, good low temperature performance, excellent viscosity temperature performance, energy saving and environmental protection performance. GL-5 level is optional for general equipment. The viscosity level can be 80w-90, 85w-90 and 85w-140 according to the load and ambient temperature.
