Radial shaft seals that are primarily used for contaminant exclusion should be installed with the lip pointing outward. When additional protection is needed, SKF recommends a seal design that incorporates an auxiliary lip, for example the HMSA10 or CRWA1 seals.
V-rings (fig 4) are used primarily to exclude contaminants. These seals, which act as flingers, rotate with the shaft and seal against a surface that is perpendicular to the shaft.
V-rings and axial clamp seals are often used as secondary seals to protect the primary seals from coarse contaminants.
None of these seal arrangements are intended for oil retention.