Oil seal is a kind of sealing parts with many applications and huge market demand. It’s sealing effect is mainly reflected in two aspects:
First, when the device is stationary, the interference fit between the sealing lip and the shaft forms a static seal.
Second, when the device is working, the fitting area of the sealing lip and the shaft is produced a thin layer of lubricating oil film, forming the dynamic sealing effect of the oil seal.
The oil seal is composed of three parts: a self-tightening coil spring,a sealing base and a metal frame. Among them, the sealing base body is made of a material having high elasticity.
Under the vibration of mechanical equipment and the pressure of the fluid medium, the sealing lip and the surface of the shaft can still form and maintain a close contact state, maintaining a stable sealing effect.
Common materials for oil seals
(1) Nitrile oil seal has good oil resistance and aging resistance, and has excellent air tightness and water resistance.
(2) FKM oil seal has the characteristics of resistance to oil, high temperature and corrosion of many types of chemical solutions.
(4) Silicone rubber seal is excellent in ozone resistance, atmospheric aging resistance, heat resistance and cold resistance, and dielectric properties. It can work for a long time at -60 ℃ ~ 250 ℃ (even wider temperature range).
Generally, it is better to choose a rubber with a hardness between 65 and 75 (Shore A) for the seal material.