Types of Common lubricating Grease
Types of Common lubricating Grease
2022年3月20日
Method for Judging Deterioration of lubricating Grease
Method for Judging Deterioration of lubricating Grease
2022年3月20日

Purpose and Mode of Lubrication

For bearings, lubrication is an important issue affecting their performance. Whether the lubricant or lubrication method is appropriate or not will greatly affect the service life of the bearing.Purpose and Mode of Lubrication

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

1) Lubricate all parts of the bearing to reduce the rotary friction between the channel surface and the steel ball, the sliding friction between the steel ball and the retainer, and the sliding friction between the retainer and the channel guide surface

2) Take away the heat generated by the internal friction of the bearing and other heat transmitted from the outside to prevent the heating of the bearing and the deterioration of the lubricant

3) Make the rolling contact surface of the bearing often form an appropriate oil film, alleviate the concentrated stress of impact load and prolong the fatigue life of the bearing. 4) prevent the corrosion of steel ball, channel and retainer, the invasion of garbage, foreign matter and moisture, and the rust prevention and dust prevention of the bearing

grease

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 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.

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 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 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 Lubrication2) 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 Lubrication

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

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

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

(7) Oil air lubrication

Standard lubricant

Grease is a semi-solid lubricant composed of base oil, tackifier and additives. It is necessary to select the grease suitable for use according to its combination.

(1) Base oil

Mineral oil is generally used as the base oil of oil, but in order to improve heat resistance and low-temperature fluidity, synthetic oils such as silicone oil are also used.Purpose and Mode of Lubrication

(2) Tackifier

Tackifiers include various composite agents, which are used to control the characteristics of mechanical stability, water resistance, service temperature range and so on.Purpose and Mode of Lubrication

(3) Additive

Add various additives according to the purpose of use.

·Extreme pressure additives make the shock load and heavy load characteristics upward.

·Oxidation additives prevent oxidation deterioration when there is no supplement for a long time.

·Anti rust additives prevent corrosion of bearings and their surroundings.

(4) Viscosity

Indicates the degree of grease hardness, which is the physical quantity of the depth of grease poured into the metal cone with the specified weight within 5 seconds (expressed as 0.1mm). The larger the value, the softer.Purpose and Mode of Lubrication

(5) Drop point

The oil turns into flowing state after heating. The temperature when dropping from the specified hole is called dropping point. The higher its value is, the higher the service temperature is.Purpose and Mode of Lubrication

(6) Mixing of different oils and fats

When viscosifiers and additives are mixed, the properties of oils and fats change. Therefore, in principle, different oils and fats should not be mixed.Purpose and Mode of Lubrication

(7) Sealing amount of grease

(8) Grease life

(9) Grease replenishing clearance

Purpose and Mode of Lubrication

Automotive general lithium grease, which is a kind of grease widely used in modern automotive industry. It has the characteristics of long service life, good water resistance and good lubrication effect. It is a substitute for ordinary butter. It can be used for the lubrication of most automobiles. Its service life is twice that of calcium based grease.Purpose and Mode of Lubrication

Calcium base grease, which is commonly known as butter. Grease is the most widely used grease in the current automobile maintenance industry. This grease is a technology from the 1930s. In developed countries, it is already an obsolete product. Because of its low price, it is also widely used in the automobile maintenance industry. It is strongly recommended not to use such products again. At least don’t use it in your own car.Purpose and Mode of Lubrication

Extreme pressure composite lithium base grease, which is a kind of grease with higher extreme pressure and wear resistance than general lithium base grease. Note that different grades of lubricating oil are suitable for different service conditions.Purpose and Mode of Lubrication

Generally speaking, the larger the number, the more viscous it is. Generally, it can be used throughout the year in the South 2#, and in winter in the North 1#. 3# only for tropical heavy-duty vehicles. Of course, strictly speaking, the choice of grease is also affected and restricted by other factors. 

Even if high-quality grease is used, the performance of the grease is degraded and the lubrication performance is low due to long-term use and the surrounding environment. 

Therefore, it is necessary to supplement and replace the grease in time. Generally, the operating temperature of about 50 ℃ is once a year. If it exceeds 100 ℃, even if there is good heat resistance, it can be exchanged 2 ~ 3 times a year.Purpose and Mode of Lubrication