Many people usually come into contact with the oil seal. The oil seal is a mechanical element used to seal the liquid medium (including oil, water, etc.), which isolates the parts in need of lubrication in the transmission parts from the external environment, so that the lubricating oil will not leak.

TC oil seal model section

The above figure is a cross-sectional view of TC oil seal

The commonly used oil seals are TC, SC, TB, Sb, Ta and SA. Many people are not particularly familiar with TF and SF oil seals. Let's talk about TC / SC and TF / SF oil seals.

First of all, these four types of oil seals belong to one type of skeleton oil seal. They all belong to inner package skeleton oil seal, and their movement mode belongs to rotary type,

1. TC type

TC type oil seal is the most commonly used oil seal form in modern industry. TC is the double lip skeleton oil seal wrapped with rubber on the inner skeleton. It is also called lip seal in some places, in which T represents double lip and C represents rubber coated on the outside. The main lip of the double lip framework oil seal is used to prevent oil and the auxiliary lip is used to prevent dust.

2. SC type

SC type oil seal is a rubber skeleton oil seal with a single lip. Compared with TC type, it lacks a dust-proof lip, which is suitable for sealing in a dust-free environment.

3. TF type

TF oil seal is not a very common type of oil seal in daily sealing equipment, because it belongs to rubber coated iron shell oil seal. Generally, the cost of this type of oil seal is much higher than that of TC type, which is commonly used in corrosive environment. Since the carbon steel shell skeleton of oil seal has no resistance to corrosive environment, it is necessary to completely cover the iron shell skeleton of oil seal with specific corrosion-resistant rubber to protect the oil seal skeleton, In this way, there will be no corrosion. Generally, TF oil seals are made of fluororubber and stainless steel spring, so they can be used for a long time in high temperature and corrosive environment.

4. SF type

Like TF type oil seal, SF type oil seal is a rubber fully coated iron shell skeleton oil seal. The difference between SF and TF is that SF is a single lip seal suitable for dust-free environment, while TF is a double lip seal, which is both dust-proof and oil-proof.

TF type oil seal

Several common types of oil seals are introduced above. They can only be used in the environment with pressure ≤ 0.3bar. In the specific selection, we also need to consider the influence of temperature and speed in the actual sealing environment on the selection of rubber materials. The commonly used oil seal materials include nitrile rubber, fluorine rubber, nitrile rubber and silicone rubber. Nitrile rubber has the widest application range at present due to its low cost, oil resistance and wear resistance, However, its disadvantage is that it is not resistant to high temperature and high speed, so it can only be applied to the environment with temperature less than 100 degrees. If the temperature resistance exceeds 100 degrees, hydrogenated nitrile rubber or fluororubber should be considered. If it exceeds 150 degrees, fluororubber must be used. If it exceeds 200 degrees, perfluoroether ffkm material should be considered. This rubber has higher chemical stability, can withstand more than 1600 chemical media, and the maximum temperature resistance can reach 320 degrees Celsius, It is the rubber elastomer with the highest temperature resistance on the market. We will introduce ffkm in more detail later.

The above is a brief introduction to the four common oil seal models. The specific oil seal selection should be analyzed according to the actual environment.