SKF - Industrial Shaft Seals

Runout
Runout (or dynamic runout, DRO) describes the
dynamic eccentricity of the shaft. Particularly at
high speeds, there is a risk that the sealing lip,
because of its inertia, will not be able to follow
the shaft surface († fig. 8). If the eccentricity
is such that the distance between the sealing lip
and shaft becomes larger than that required to
maintain a hydrodynamic lubricant film, the
medium to be sealed will escape through the
gap. It is therefore advisable to arrange the seal
in close proximity to the bearing and to keep
bearing operating clearance to a minimum.
Permissible runout values can be obtained
from diagram 4 on page 62. These values are
normally lower for narrow seals.
2
Fig. 8
Runout
61