Plain Bearings
Damage Types in Plain Bearings
Causes, Phenomena and Treatment Methods of Bearing Temperature Rise
Causes, Phenomena and Treatment Methods of Bearing Temperature Rise

Seal Type of Bearing

In order to maintain good lubrication conditions and normal working environment of the bearing, give full play to the working performance of the bearing and prolong the service life, the rolling bearing must be properly sealed to prevent the leakage of lubricant and the invasion of dust, moisture or other dirt.Seal Type of Bearing

The sealing of bearings can be divided into self sealing and external sealing. The so-called bearing with seal is to make the bearing itself into a device with sealing performance. Such as bearing with dust cover, sealing ring, etc. This kind of seal occupies a small space, is convenient for installation and disassembly, and the cost is relatively low.Seal Type of Bearing

The so-called bearing external sealing performance device is to make a sealing device with various properties inside the installation end cap and other {today hot}.

The following main factors shall be considered in the selection of bearing external seal:Seal Type of Bearing

1. Bearing lubricant and type (grease and oil);

2. The working environment of the bearing and the size of the occupied space;

3. The support structure of the shaft has advantages, and the allowable angle deviation;

4. Circumferential speed of sealing surface;Seal Type of Bearing

5. Working temperature of bearing;Seal Type of Bearing

6. Manufacturing cost.Seal Type of Bearing

The external seal can be divided into non-contact type and contact type. It is described as follows:Seal Type of Bearing

1) Non contact seal

Non contact seal is a seal with proper clearance and no contact between the seal and its relative moving parts. This type of seal produces almost no friction heat and no wear in operation. It is especially suitable for high-speed and high-temperature occasions. Non contact seals are commonly used in various structural forms, such as gap type, labyrinth type and gasket type, which are used in different occasions.

The clearance of non-contact seal should be as small as possible.

Seal Type of Bearing

2) Contact seal

Contact seal is a seal that is in contact with its relative moving parts and has no gap. Due to the direct contact between the seal and the mating part, the seal has large friction and heat generation in the work, which is easy to cause poor lubrication and easy friction loss of the contact surface, resulting in the decline of sealing effect and performance. Therefore, it is only applicable to medium and low speed working conditions. The common structural forms of contact seal include felt seal, leather cup seal and so on, which are used in different occasions.

It should be pointed out that the martensite obtained in this case is cryptocrystalline martensite, and the measured carbon content is the average carbon content. In fact, the carbon content in martensite is uneven in the micro region, and the carbon concentration near the carbide is higher than that far away from the original ferrite part of the carbide.Seal Type of Bearing

 Therefore, they begin to undergo martensitic transformation at different temperatures, which inhibits the growth of martensitic grains and the display of microstructure and becomes cryptocrystalline martensite. It can avoid the micro cracks that are easy to appear when high carbon steel is quenched, and its substructure is dislocation plate and strip martensite with high strength and toughness. 

Therefore, only when medium carbon cryptocrystalline martensite is obtained when high carbon steel is quenched can the bearing parts obtain the matrix with anti failure ability.

According to the requirements of bearing working conditions and working environment for sealing degree, various sealing forms are often used comprehensively in engineering design to achieve better sealing effect.