Manufacturing and Quality Control
First, an elastomer, most often nitrile, is vulcanised to a metal ring. This creates a stiffening effect that includes a specialised metal tension spring directly behind the sealing lip, keeping the oil seal firmly in place against the moving part.
NBR, also known as nitrile rubber or nitrile, is the most popular material for an oil seal because of its good resistance to many oils and greases, such as mineral grease and hydraulic oil. Depending on their composition, synthetic oils and greases, such as those based on glycol, can damage NBR rubber materials. Depending on the amount of glycol, a PTFE lip seal may be the best choice. NBR is also unable to cope with contact with acids and solvents. The rubber is suitable for oil and grease at temperatures from -35 °C to 100 °C.
Usually, these oil seals are used to seal lubricating oil or grease and contain it within the application, so that moving parts such as bearings are continually supplied with enough lubrication. However, such seals are also used for sealing other liquids, gases, and solids, such as powders or granules.
The lip is specially designed to ensure the oil seal works effectively with the different forces that arise during rotation. Many different designs and materials are used, so countless types of oil seals are available. These are chosen according to the application; pumps, gearboxes, wheels, and many other rotating applications where fluids need to be sealed. They are used in a variety of sectors, such as the chemical industry, manufacturing, wind turbines, automotive sector, food industry, and more. Oil seals are used in nearly all sectors.
Oil Seals 101 – The Ultimate Guide
Shaft Hardness
In recent research, MWCNTs and carbon black were mixed with the butadiene/natural rubber to form a hybrid composite which gives very strong filler links by partial replacement of carbon black based on the m1:m2:X (m1—MWCNT; m2—reduction amount of carbon black; X-varies from 1 to 6) [40,64]. An internal blending mixer and two-roll milling were used to formulate the composites. The synergistic effect plays a major role in improving the abrasion resistance property due to the partial replacement of carbon black by adding MWCNTs in different ratios. The optimal ratio value of MWCNTs is 5 (parts per hundred of rubber) and 27.5 (parts per hundred of rubber) for carbon black with better resistant to abrasion compared to the matrix material [64]. The vulcanized hybrid composite material reinforced with MWCNT/carbon black at the ratio of 1:1 shows better mechanical properties, curing characteristics, and thermal conductivity. This shows a better tyre thread with an improved endurance life, less curing time, and improved thermal conductivity [42,64]. Fig. 4.4 shows the SEM and TEM images of uncured and cured rubber and Figs. 4.5 and 4.6 show the application of rubber nanocomposites in a tyre application.



