, also known as a packing, or a toric
, is a mechanical
in the shape of a
; it is a loop of
, designed to be seated in a groove and
compressed during assembly between two or more parts,
at the interface.
The joint may be static, or
(in some designs) have relative motion between the parts
and the o-ring; rotating
pump shafts and
hydraulic cylinders, for example. Joints with motion
lubrication of the o-ring to reduce wear. This is
typically accomplished with the fluid being sealed.
O-rings are one of the most common seals used in
machine design because they are inexpensive and easy to
make, reliable, and have simple mounting requirements.
They can seal tens of
megapascals (thousands of