Cylindrical roller bearings with four or more rows of rollers are used almost exclusively for rolling mills. They have lower friction than other roller bearings and can be successfully used where high speed operation is called for. The low cross-sectional height of cylindrical roller bearing means that the roll necks can have large diameter in relation to the roll itself. Cylindrical roller bearing with more than four rows of rollers and cages are used primarily for small cold rolling mills and for flat products where the rolling forces are considerable and rolling speed high. Multi-row bearings are produced for roll neck diameters of up to approximately 220mm. The outer ring is without flanges. Limited axial displacement of the shaft with respect to the housing can therefore be accomodated by the bearing.
The dimensions of the bearing with the series designations listed in the tables comply to ISO 15-1981.
Multi-row cylindrical roller bearings are not designed to accomodate any misalignment.
Excluding particular request of customers, six row cylindrical roller bearings are menufactured to normal tolerance class specifications.
RADIAL INTERNAL CLEARANCE
Six row cylindrical roller bearings are manufactured with radial internal clearance that depending on the application. On costumers request are available bearings with different radial internal clearances. All cylindrical roller bearings that present helical groove on the inner ring bore are made with C2 radial internal clearance.
In relation to the execution, multi-row cylindrical roller bearings are fitted with either two double pringe machined roller guided cages of brass or steel, pin-types cage of steel (with pierced roller) or machined cage of brass with vent-hole. Some execution are supplied with steel pressed sheet.
With some special exceptions, multi-row cylindrical roller bearings are undergo special stabilizing treatment S0 which makes them suitable for operating temperatures up to +150°C. On customers request it’s possible have other stabilizing treathment as:
> S1 (for working up to +200°C)
>S2 (for working up to +250°C)
A/B/C/D/E – Deviating or modified internal design
C2 – Radial internal clearance less than Normal
C3 – Radial internal clearance greather than Normal
C4 – Radial internal clearance greather than C3
C5 – Radial internal clearance greather than C4
HA1 – Case-hardening of outer and inner rings
HA2 – Case-hardening of outer ring
HA3 – Case-hardening of inner ring
HA4 – Case-hardening of rollers, outer and inner rings
HB1 – Bainitic hardening for outer and inner rings
HB2 – Bainitic hardening for outer ring
HB3 – Bainitic hardening for inner ring
G – Helicoidal groove on the bore
K/K30 – Tapered bore, 1:12 on diameter (K); 1:30 on diameter (K30)
M – Machined brass cage
P4/P5/P6 – Dimensional and running accuracy to ISO tolerance class 4/5/6
VJ202 – Two rows bearing group
W – Lubrication groove on rings surface
WI – Lubrication groove on inner rings surface
WO – Lubrication groove on outer rings surfaces
W33 – Lubrication groove and three holes in outer ring
S0 – Stabilized rings up to 150°C
S1 – Stabilized rings up to 200°C
S2 – Stabilized rings up to 250°C
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