NNU4922B/SPW33 bearings ( 110 mm x 150 mm x 40 mm) have the advantages of Ultimate stability, ultimate precision, ultimate durability, and are therefore widely used in the Machine tool spindles, high-speed motors, precision rolling mills, industrial robots, and aerospace equipment.

| Part Number | NNU4922B/SPW33 |
| Interchangeable | SKF NNU4922B/SPW33 |
| Cage | Machined brass cage, prong-type, roller centred |
| Bearing Type | Cylindrical roller bearing, double row, super-precision |
| Load | radial |
| Accuracy class | SP (ABEC 7) |
| Coating | NO |
| Bearing part | Complete |
| Internal design | B = Modified internal design |
| Dimension series | 49 = ISO dimension series 49 |
| Design | NNU |
| Internal clearance | CN |
| Row NO. | Two |
| Seal | Open |
| Number of ring | outer ring(3), inner ring(0) |
| Units | Metric |
| Manufacturer Part Code | NNU 4922 B/SPW33 |
| Series | NNU 49 series (NNU 49.. B/SPW33) |
| Lubrication | NO |
| Relubrication feature | W33 = Annular groove and three lubrication holes in the outer ring |
| Loose flange | NO |
| Weight [lb] | 4.4974 |
| Cr Radial Dynamic [lbf] | 29631 |
| C0r Radial Static [lbf] | 60389 |
| Pu Fatigue load limit [lbf] | 6591 |
| nB Speed ratings (grease) [rpm] | 5223 |
| nG Speed ratings (oil) [rpm] | 5904 |
| d φ Inside [inch] | 4.3307 |
| D Φ Outside [inch] | 5.9055 |
| B Thickness [inch] | 1.5748 |
| F [inch] | 4.843 |
| b [inch] | 0.2165 |
| K [inch] | 0.1181 |
| r1,2 min Chamfer [inch] | 0.0433 |
| r3,4 min Chamfer [inch] | 0.0433 |
| D1 [inch] | 5.3464 |
| dn Oil nozzle [inch] | 4.8819 |
| s max. Permissible axial displacement [inch] | 0.0433 |
| ra max Radius of fillet [inch] | 0.0394 |
| db min [inch] | 4.9606 |
| da min [inch] | 4.5669 |
| Da max [inch] | 5.650 |
| da max [inch] | 4.764 |
| Gref Reference grease quantity | 17 |
| Static radial stiffness [N/µm] | 3130 |
The NNU4922B/SPW33 Ultra-precision cylindrical roller bearings are primarily composed of high-precision inner and outer rings (bearing steel precision ground to P4 grade or higher), cylindrical rollers (high-graded, often logarithmically modified), and a cage (solid brass or outer ring guided type). Common structures are the N10 series (single row) and NN30 series (double row), with separable inner and outer rings for easy installation.
Ultra-precision cylindrical roller bearings offer extremely high radial stiffness and load-carrying capacity, making them suitable for precision spindles requiring heavy loads and high rigidity. They feature high limiting speeds, optimized roller end face and flange contact to reduce friction and heat generation. Precision grades can reach P4 to P2, providing smooth rotation and low vibration. They can be used as floating end bearings to compensate for thermal expansion and maintain high positioning accuracy.















