BCM’s tandem bearings are primarily used when reliable support must be provided for high axial forces in a limited radial design envelope. A typical application for tandem bearings is the distribution gear in twin screw extruders (Figure 2).
The power range found in twin screw extruders ranges from approx 2 kW and 16 MW. The back pressure forces are also quite high: theyrange from 2.5 to 3,400 kN.
Tandem Bearing Design
Tandem bearings consist of several coaxially arranged thrust cylindrical roller and cage assemblies. Two, three or four thrust cylindrical roller and cage assemblies can be used, corresponding to product designations T2AR.., T3AR.. and T4AR.. respectively. Six row and eight row tandem bearings (T6AR.. and T8AR..) are also available. These products consist of two triple row and two four row tandembearings respectively.
The special elastic system of matched rings and washers made from hardened rolling bearing steel ensures that there is an equal load on all rows regardless of the magnitude of the axial load. Benchmarking performed at INA has shown that a comparable competitor product has been designed only for a certain point of operation. Axial loads deviating from this point are not supported equally across all stages.