The sealing lip is always made of a rubber or synthetic material. For oil seals with a rubber outer case (R, RST, GR, GRST), the rubber quality of the sealing lip and the outer case are the same.
Selecting Quality Silicone and Rubber Gaskets
There is a British Standard laid down for the control of synthetic rubbers. BS 3574 (1989) helps to determine shelf life – for instance, Nitrile (NBR) and Polyacrylic (ACM) are Group ‘B’ rubbers and have a 7-year life, whilst Silicone (VMQ) and Fluoroelastomers (Viton®) are Group ‘C’ rubbers and have a 10-year shelf life. PTFE and Leather do not come into this category but like the others should be kept in the original packing for as long as possible away from direct light, dust, and humidity. Ozone, which can also be produced by battery-driven forklift trucks has a very bad effect on synthetic rubbers. Finally, protect the sealing lip – DO NOT hang the seals on nails, wire etc.
The basic principle of sealing is straightforward – the flexible lip is held against the rotating part (usually the shaft) whilst the casing (or O.D.) is pressed into the housing or bore and holds the seal in place. The sealing lip needs some form of lubrication to avoid overheating and is usually energized by means of a garter spring.
PTFE Lip seals
A piston oil seal, also known as a piston seal ring, is a critical component in an internal combustion engine. It plays a crucial role in preventing oil leakage from the piston and ensuring efficient engine operation.