3R8-68N3B Bore 1493.4184 Mm, Heavy Duty Three Row Roller Slewing Rings With Internal Gears
The 3R8-68N3B Three-row roller slewing bearings are widely used in ultra-heavy equipment with extremely high load-bearing capacity requirements, which need to withstand both massive wind loads and overturning moments, such as ultra-large tonnage cranes (crawler cranes, tower cranes), tunnel boring machines (cutterhead drive), large wind power (main bearings), port machinery (ship unloaders), mining machinery (crushers), and marine engineering equipment, among other fields.
The 3R8-68N3B bearing is a Heavy Duty Three Row Roller Slewing Rings With Internal Gears with an inner diameter of 1493.4184 mm , an outer diameter of 1892.3 mm, a width of 142.748 mm. 50Mn or 42CrMo rings, chrome-alloy steel rolling mlement. Seal on one side only type, together determine its load-bearing capacity, rotational accuracy, and applicable working conditions.
3R8-68N3B bearings ( 1493.4184 mm x 1892.3 mm x 142.748 mm) have the advantages of The strongest load-bearing capacity, independently bears the load, and has a robust and reliable structure, and are therefore widely used in the Heavy tower cranes, truck cranes, large excavators, wind turbines and tunnel boring equipment.
| Part Number | 3R8-68N3B |
| Bearing Type | Heavy Duty Three Row Roller Slewing Rings With Internal Gears |
| Gears type | Internal Gear |
| Units | inch |
| Seal | Seal on one side only |
| Seal Material | NBR (Nitrile Butadiene Rubber) |
| Rows NO. | Three |
| Outside - OD Φ [inch] | 74.50 |
| Inside - ID φ [inch] | 58.796 |
| IO [inch] | 66.57 |
| OI [inch] | 66.50 |
| Overall Hight - HT [inch] | 5.62 |
| OH [inch] | 5.43 |
| IH [inch] | 5.00 |
| K [inch] | 0.62 |
| Mounting Holes - OBC [inch] | 72.000 |
| OU [inch] | 1.19 |
| No. Holes - OBC | 28 |
| Mounting Holes - IBC [inch] | 64.125 |
| IU [inch] | 1.31 |
| No. Holes - IBC | 48 |
| PD [inch] | 59.333 |
| DP [inch] | 1.5 |
| No. Of Teeth | 89 |
| F [inch] | 5.00 |
| Tooth Form 20˚ | Full Depth |
| Gear hardness (BHN) | 250-300 |
| Max. Tangential Tooth Load [lbs] | 57100 |
| Nominal Capacity Compressive Thrust [lbs] | 2380000 |
| Nominal Capacity Moment [ft-lbs] | 2978000 |
| Nominal Capacity Curve No. | 8-68 |
| Nominal Capacity Radial [lbs] | 340000 |
| Weight [lbs] | 2070 |
The 3R8-68N3B Three-row roller slewing bearings mainly consist of an upper ring, a lower ring, a middle ring, three rows of independent rollers (two rows of axial rollers at the top and bottom, and one row of radial rollers in the middle), spacers, and a sealing device. The three rows of raceways are separate and do not interfere with each other, resulting in a clear structural layout.
Three-row roller slewing bearings have the strongest load-bearing capacity. The three rows of rollers respectively bear axial force, radial force, and overturning moment, resulting in a reasonable load distribution. They exhibit excellent rigidity and impact resistance, have a long service life, and are suitable for heavy-duty rotation under extremely heavy loads and harsh working conditions.
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