Basic Knowledge of INA BearingThe codes of bearings consist of basic code, pre-code, and post-code. Basic code stands for the basic type, structure and dimensions of bearings; post-code stands for the complementary code which is added to the end of the basic code in case there are some changes happen to the structure, dimensions, sealing, cage, tolerances, clearances, packages, and technical requirements of bearings.
[Retainer, seal ring and cover]
Z - bearing with a dust-proof cover on one side of it.
2Z - bearing with dust-proof covers on both sides of it.
ZW - roller pin and retainer assembly, double row.
P - bearing with a seal ring on one side of it.
PP - bearing with seal rings on both sides.
D - split-casting roller pin and retainer assembly.
RS - bearing with a seal ring on one side of it.
2RS - bearing with seal rings on both sides of it.
V - sealed bearing.
TN - plastic retainer.
X - bearing and accessories with dimensions changed to meet requirements of international standard. This complementary code is only used in transition period. While the general structure is spheric rolling plane, X also means the supporting roller and curve roller which have the cylindrical rolling plane.
[Special tolerance and accuracy]
P - bearing with its dimensions tolerance and geometric accuracy meet the general standard. (no complementary code is needed.);
P6 - bearing with its dimensions tolerance and geometric accuracy meet relatively high standard;
P5 -bearing with its dimensions tolerance and geometric accuracy meet high standard;
P4 - bearing with its dimensions tolerance and geometric accuracy meet extremely high standard;
C2 - initial radical clearance is below C0;
C0 - normal initial radical clearance. (no complementary code is needed.);
C3 - initial radical clearance is above C0;
C4 - initial radical clearance is above C3;
These complementary codes could be used in combination for bearing with relatively high standard dimensions tolerance and geometric accuracy and its initial radical clearance is different from that of the normal value;
H+…+…－ bearing without inner ring with its inscribed circle diameter tolerance scope becoming narrower;
G - quality grade of roller pin;
SORT - diameter classification of roller pins in roller pins and retainer assembly, the unit of tolerance is micron;
GP - bearing that has passed noise test;
2S, 3S, S - this complementary code is used for two or more bearings which are tandemly mounted and with the load evenly distributed; the foregoing number means the number of the selected and matched bearings which are of the same series and dimensions, the bearing and its accessories which are matched can not be interchanged.