Causes, Phenomena and Treatment Methods of Bearing Temperature Rise
Causes, Phenomena and Treatment Methods of Bearing Temperature Rise
2022年3月18日
Simple Identification of Lubricating Oil and Grease
Simple Identification of Lubricating Oil and Grease
2022年3月19日

Purpose and Mode of Bearing Lubrication

For bearings, lubrication is an important issue affecting their performance. The suitability of lubricants or lubrication methods will greatly affect the life of bearings.

The functions of lubrication are as follows:Purpose and Mode of Bearing Lubrication

1) Lubricate all parts of the bearing to reduce friction and wear

2) Take away the heat generated by friction or other reasons inside the bearing

3) The rolling contact surface of the bearing often forms an appropriate oil film to prolong the fatigue life of the bearing

4) Rust prevention and dust prevention of bearings

The lubrication methods of bearings are mainly divided into grease lubrication and oil lubrication. The general comparison is shown in Table 1:

Table 1 Comparison between grease lubrication and oil lubrication

Project fat

The sealing device is simple and complex, and attention should be paid to maintenance

The lubrication performance is very good

Low speed – medium speed can also be used for high speed

The replacement of lubricant is troublesome and simple

The service life of lubricant is short and long

Poor cooling effect (circulation required)

It is difficult and easy to remove impurities

Grease lubrication can be filled with grease for a long time without supplement, and the structure of its sealing device is relatively simple, so it is widely used.

Grease lubrication includes the sealing method of filling grease in the sealed bearing in advance, and the filling grease supply method of filling an appropriate amount of grease in the shell and replenishing or replacing it at regular intervals.Purpose and Mode of Bearing Lubrication

In addition, for machines with multiple bearings that need lubrication, the centralized grease supply mode of connecting pipes to each lubrication point is also adopted.Purpose and Mode of Bearing Lubrication

1) Filling amount of grease

The filling amount of lubricating grease in the shell varies with the structure and volume of the shell. Generally, it is appropriate to fill it to 1 / 3-1 / 2 of the volume.Purpose and Mode of Bearing Lubrication

When the filling amount is too much, the lubricating grease will deteriorate, age and soften due to stirring and heating, which should be paid attention to.Purpose and Mode of Bearing Lubrication

However, when it is used for low-speed bearings, it is sometimes filled to 2 / 3-1 of the volume in order to prevent the invasion of foreign matters.Purpose and Mode of Bearing Lubrication

The lubrication methods of bearings are divided into grease lubrication and oil lubrication. In order to make the bearing function well, first of all, choose the lubrication method suitable for the use conditions and purposes. If only lubrication is considered, the lubricity of oil lubrication is dominant. However, grease lubrication has the advantage of simplifying the structure around the bearing. Compare the advantages and disadvantages of grease lubrication and oil lubrication.

Purpose and Mode of Bearing Lubrication

2) Supplement and replacement of lubricating grease

The supplement and replacement of lubricating grease are closely related to the lubrication method. No matter what method is adopted, clean lubricating grease must be used, and attention must be paid to prevent the invasion of external foreign matters.

The lubricating grease to be supplemented shall be of the same brand.Purpose and Mode of Bearing Lubrication

When replenishing grease, it is particularly important to ensure that the new grease does enter the bearing.Purpose and Mode of Bearing Lubrication

 

Oil lubrication

Oil lubrication is suitable for high-speed bearings and can withstand a certain degree of high temperature. It is also effective in reducing vibration and noise. It is mostly used in occasions where grease lubrication is not suitable.

Oil lubrication is generally divided into:Purpose and Mode of Bearing Lubrication

(1) Oil bath lubrication (2) drip lubrication (3) splash lubrication

(4) Circulating lubrication (5) jet lubrication (6) oil mist lubrication

(7) Oil air lubrication

Reduce friction and wear.

The contact parts of the ring, rolling element and retainer constituting the bearing prevent metal contact and reduce friction and wear.

Extend fatigue life.

The rolling fatigue life of the bearing is prolonged when the rolling contact surface is well lubricated during rotation. On the contrary, if the oil viscosity is low and the lubricating oil film thickness is not good, it will be shortened.

Discharge friction heat and cooling.

Circulating oil supply method can use oil to discharge the heat generated by friction or the heat transmitted from the outside for cooling. Prevent the bearing from overheating and the lubricating oil from aging.

other

It also has the effect of preventing foreign matters from invading the interior of the bearing, or preventing rust and corrosion.