DIMENSION SERIES

SINGLE ROW:

•    N – open-end outer ring
•    NF – one-sided open-end outer ring
•    NP – closed-end outer ring and retaining ring P
•    NU – open-end inner ring
•    NUB – extended open-end inner ring
•    NUC – open-end inner ring (as NU, but different make of the inner ring)
•    NUJ – NU bearing and HJ angular ring
•    NJ – one-sided open-end inner ring
•    NH – NJ bearing and HJ angular ring
•    NJP – NJ bearing with a separate lip in the form of the P retaining ring
•    NUP –- one-sided open-end inner ring and additionally the P retaining ring
The  dimension  series  listed  below  are  characteristic  for various solutions described above:
•    18.. 38.. 48.. 19.. 29.. 39.. 49.. 69.. 10.. 20.. 30.. 40.. 50.. 31.. 51.. 2.. 12.. 22.. 32.. 52.. 3.. 23.. 33.. 4..
Cylindrical  roller  bearings  are  dismountable  and  after  removing  the  free  ring we always get  the  following  types of bearings:
•    RNU – without the inner ring or
•    RN – without the outer ring.

DOUBLE ROW:

•   NN 30.. NN31.. NN48.. NN49.. NN40..
•   NN 30..K NN31..K NN48..K NN49..K NN40..K
•   NNU 49.. NNU60.. NNU41..
•   NNU 49..K NNU60..K NNU41..K

STRUCTURE

Because of the wide variety of construction types it is very difficult to describe in detail the structure of cylindrical roller bearings. On the whole, though, cylindrical roller bearings consist of the cage with rollers, which  is fixed  to one of  the rings (to the inner ring in the N, NP and NF makes and to the outer ring in the NU, NJ, NUP and NH makes), and the second, free  ring  of  diversified  structure. And  precisely  this  diversified  structure  of the  free  ring  contributed  to  such  great number of construction types. Individual construction types have been listed above in the form of dimension series. The key feature of all cylindrical roller bearings is their dismountability, of course, besides bearings that lack free rings.