... bearings, its outer wall to double, a single inner wall. NF-cylindrical roller bearings, the outer ring of single-wall, double inner wall. NJ and ... type, for non-bearing inner ring, outer ring has a double wall, that is, without the inner-NU cylindrical roller bearings. ... Man-loaded roller cylindrical roller bearings The general use of double-wall outer ring, inner ring of single-block structure, that ...