312943/1YD bearings ( 240 mm x 330 mm x 220 mm) have the advantages of Extremely high radial load capacity, high rigidity, separable design, and are therefore widely used in the metallurgical rolling mills, large gearboxes, and heavy-duty extrusion presses.

| Part Number | 312943/1YD |
| Interchangeable | KOYO 312943/1YD |
| Desgin Figure | 1-4 |
| Cage | Machined brass cage |
| Radial internal clearance | C3 |
| Seal | Open |
| Bearing Type | Four-row cylindrical roller bearing for cold rolling mill, hot rolling mill, billet mill |
| Equivalent | FC4866220A (China) 313921 (SKF) 508368 (FAG) 240RV3301 (NSK) 4R4811 (NTN) 312943/1YD (KOYO) |
| Design type | Outer ring with rib, One inner ring |
| Bearing Weight [lb] | 122.355 |
| d φ Inside [inch] | 9.449 |
| D Φ Outside [inch] | 12.992 |
| B Width [inch] | 8.661 |
| Fw Raceway diameter inner ring [inch] | 10.630 |
| C [inch] | 8.661 |
| r min Chamfer outer ring | 3 mm |
| r1 min Chamfer inner ring | 3 mm |
| Cr Radial Dynamic [lbf] | 400144 |
| C0r Radial Static [lbf] | 955400 |
| Mounting dimensions | |
| da min shaft [inch] | 10.000 |
| Da max housing [inch] | 12.441 |
| Da min housing [inch] | 12.205 |
| ra max Fillet radius [inch] | 0.098 |
| rb max Fillet radius [inch] | 0.098 |
The 312943/1YD Four-row cylindrical roller bearings mainly consist of an inner ring, an outer ring, four rows of cylindrical rollers, a cage, and a spacer. Common structures use a configuration of double outer rings (each with double raceways) and a single inner ring (with four raceways), or an interchangeable combination of inner and outer rings. Axial positioning and load distribution are achieved through the spacer.
The advantages of four-row cylindrical roller bearings are their extremely high radial load capacity, high rigidity, and the line contact between the rollers and raceways, resulting in a low coefficient of friction and allowing for high-speed operation under heavy loads. They can also be used as floating end bearings, capable of withstanding axial displacement caused by thermal expansion, and are easy to install and maintain.















