NNU 4948 BK/SPW33
Super-precision double row cylindrical roller bearing with lubrication feature
Super-precision double row cylindrical roller bearings in the NNU 49 series are designed to accommodate heavy radial loads and high speeds, while providing a high degree of stiffness.
Having three flanges on the outer ring and no flanges on the inner ring, the bearings can accommodate axial displacement in both directions. The separable design simplifies mounting and dismounting, particularly when load conditions require both rings to have an interference fit.
- High radial load carrying capacity
- Very high rigidity and high running accuracy
- Minimize noise, vibration and heat generation
- Accommodate axial displacement in both directions
- Lubrication feature
- Thin section enabling compact application design
Dimensions
| d |
240 mm
|
Bore diameter |
| D |
320 mm
|
Outside diameter |
| B |
80 mm
|
Width |
| D1 |
292.2 mm
|
Shoulder diameter outer ring (NNU design) |
| F |
265 mm
|
Raceway diameter inner ring (NNU design) |
| b |
11.1 mm
|
Width annular lubrication groove at outer ring |
| K |
3 mm
|
Diameter lubrication hole (outer ring) |
| r1,2 |
min.2.1 mm
|
Chamfer dimension outer ring |
| r3,4 |
min.1.1 mm
|
Chamfer dimension inner ring (bearing with tapered bore) |
| s |
max.3.7 mm
|
Permissible axial displacement from the normal position of one bearing ring relative to the other (all) |
Abutment dimensions
| da |
min.251 mm
|
Abutment diameter shaft |
| da |
max.262 mm
|
Abutment diameter shaft (NNU design) |
| Da |
max.309 mm
|
Abutment diameter housing |
| ra |
max.2 mm
|
Fillet radius |
| dn |
267 mm
|
Oil nozzle position (not for variants with TNHA cage) |
Calculation data
| Basic dynamic load rating |
C |
528 kN
|
| Basic static load rating |
C0 |
1 220 kN
|
| Fatigue load limit |
Pu |
118 kN
|
| Attainable speed for grease lubrication |
|
2 200 r/min
|
| Attainable speed for oil-air lubrication |
|
2 600 r/min
|
| Reference grease quantity |
Gref |
171 cm³
|
| Static radial stiffness (guideline value) |
|
6 340 N/µm
|
