Oil Seals vs. O-Rings

function of oil seal and O ring are same they made for sealing

but they are different in construction and application. some oil seal are made of special neoprene rubber material and having spring instead while O ring are also made of special rubber material. Oil seal used generally with rotating and sliding component while ORing is used with stationary part.

So it is decided to the material and exact work enviorment!

What is the material of oil seal and O ring do you need?

An ORing is round in shape but oil seal shape can dependent on application, every ORing can can be called an oil seal(provided it is made of rubber) but every oil seal can not be called and an ORing.

If you mean lip seal by the oil seal

Then O rings are usually best for static sealing and a small range of dynamic sealing (low RPM/ surface speed,, reciprocating motion) etc.

The lip seals are usually used for much higher velocity. Almost always for Rotary motion, but there are a few special seals for the linear one too, but are limited by the pressure handling capacity.

We all know what an O ring is. An oil seal is accomplished when oil is flung off a series of rings by centripetal force connected to a rotary to provide a thin film of oil. Pressure differentials between the rings isolate different gasses (ie; hydrogen-air) without mechanical contact, as in an O ring. Other mechanical seals are called 'gaskets'.

One difference would be its construction...

This is an O ring.. Almost always Circular in shape and a tube in width. Used in general sealing applications.

This would be an Oil seal... Grooved according to the application and almost always used in rotary applications... like Shafts..