To effectively prevent a leakage of grease existing inside a bearing or base oil in the grease to the outside regardless of a rotational direction of an outer cylinder.
While externally fitting and fixing a seal ring 19a onto parts near both ends of a roll shaft not rotating at a time of use through the medium of a ring shape member, a pad member is internally fitted and fixed onto parts near both ends of an outer cylinder rotating at a time of use. An axial outside surface of the pad member and an axial inside surface of the seal ring 19a face each other through a gap. Projections 39, 39 are formed in a plurality of parts disposed at equal intervals circumferentially in the axial inside surface, each of which has an approximately trapezoidal shape. The tilting side surfaces 40a, 40b existing circumferentially on both sides are tilted in a direction separating from each other with distance radially outward. Grease or base oil packed in the gap is discharged radially inward and circulated to the bearing side by respective projections 40a, 40b.
Nakai Shun
Kinzo Koyama