The parts that move relative to each other in the machine will experience friction and wear on their contact surfaces. According to statistics, more than one-third of the world's energy consumption is in frictional losses, which directly affect the normal operation and service life of machines when the wear exceeds the allowable limit. Therefore, adding lubricant between components in relative motion forms a lubricating oil film to reduce friction and wear, while also serving functions such as cooling, buffering, vibration absorption, and sealing.

The purpose of lubrication is not only to make the machine run faster, but more importantly, to ensure its normal operation and extend its service life.

Lubricants come in different types and have different working properties. To improve certain aspects of lubricant performance, corresponding additives should also be added. In order to provide reasonable lubrication for the machine, different types of lubricants and additives should be selected for different types, working conditions, and oil supply methods.

Therefore, it cannot be assumed that any oil can lubricate. Moreover, improper selection of lubricating oil can lead to lubrication accidents, which account for a large proportion of equipment failures.

Generally, oil lubrication can be indicated by an oil level indicator to show the oil level height. It is advisable to immerse the high-speed gear in oil at a depth of 1-2 tooth heights in the gearbox to prevent poor lubrication of the high-speed gear and reduce the resistance to gear movement and oil temperature rise. The filling amount of lubricating grease for rolling bearings generally does not exceed 1/3-1/2 of the bearing clearance.

Attention: If it is lubricated with grease, excessive resistance will increase, causing bearing heating and resulting in grease leakage, especially in high-speed and heavy-duty machines.

Viscosity is the main indicator of lubricating oil, and its standard is usually determined at a temperature of 100 ℃ to determine the grade of lubricating oil. The higher the grade, the thicker the lubricating oil film formed. Although it reduces the friction force of the friction surface, it increases the resistance, power loss, and energy waste.

When the machine is first started, the temperature is low, and a part of the lubricating oil on the friction surface is lost due to the increase in temperature after working for a period of time. Lubrication cannot form an effective lubricating oil film, and the oil cannot be quickly replenished to the friction surface of the machine. Due to the high viscosity of the oil, the flow is slow, resulting in significant wear of the parts.

The selection of viscosity should consider factors such as working speed and working temperature, and reducing the viscosity of lubricating oil is one of the current measures to save fuel.

If the lubricating oil turns black, it indicates that the lubricating oil has deteriorated and needs to be replaced. This understanding is one-sided. For example, it is normal for mechanical oil with a detergent dispersant to turn black shortly after use, and it cannot be easily assumed that the oil has deteriorated. Lubricating oil with additives often produces a dark protective oil film on the surface of the bearing, and blackening during use is also a normal phenomenon. There is no need to remove the blackened lubricant. Therefore, to determine whether the lubricating oil has deteriorated, a comprehensive analysis should be conducted and the oil should be replaced according to its quality.

In fact, besides the spoiled oil, there are also many lubricating oils that can be utilized: the replaced oil, if only mixed with impurities, can be reused after sedimentation and filtration; After simple treatment, heavily polluted oil can be used as a lubricant for rough machining equipment and rust prevention for outdoor equipment, or waste oil can be collected and handed over for recycling; Oil that is difficult to recycle can generally be burned as fuel oil after simple treatment.

The selection of lubricating oil varies depending on the working conditions, working environment, specific characteristics of the friction surface, and lubrication method of the machine. The type and brand of lubricating oil selected also differ, and generally cannot be replaced.

After a period of use, the performance of lubricating oil decreases or changes. As the oil quality decreases, if the lubricating oil is not replaced or replenished in time, it will lead to poor lubrication and easily cause high temperature phenomena.