When you take a faucet apart,
you can see a round rubber seal that keeps water from spilling.
The cylinder in a hydraulic excavator does the same thing.
The part called "O-ring" prevents oil from leaking,
and the part called "urethane seal" prevents soil
and other stuff from coming inside.
The cylinder is a shiny silver color because the surface is
extremely smooth. Even a small bump on the cylinder can cause
oil leak. |
 |
| *Image of
the cut cylinder seen from side. See how tightly it
is guarded with O-ring and the seal ? |
|
