F-55471.T2AR thrust roller bearing in plastic powder extruder machine

 F-55471-100.T2AR f-55471-100.t2ar bearing specification as following:

Tandem roller bearing structure :
Tandem 2 rows(T2AR), Tandem 3 rows(T4AR), Tandem 6 rows(T6AR), Tandem 7 rows(T7AR), Tandem 8 rows(T8AR)* Tandem thrust bearings are produced by only through orders

Application of tandem multi-stages roller bearings:

When using tandem bearings, the following recommendations should be adhered to:
1. Preload: 1% of the dynamic basic load rating. The dynamic basic load rating of each tandem bearing see Figure 1~3. Figures not listed will be provided by out institute on request.
2. Radial guidance: full complement cylindrical roller bearings or needle roller bearings can be used.

3. Eliminate tilting: the supporting parts must be machined to eliminate any tilting.
4. Mounting tolerances: recommended the following mounting tolerances: shaft f6 and housing bore F7.
5. Lubrication: tandem bearings must always be lubricated by oil circulation

How to choose the tandem cylindrical roller bearing type:

Three pieces of information are necessary when selecting a suitable tandem bearing:
– the maximum possible bearing OD
– the desired calculated rating life under operating load and speed
– the maximum screw pressure.
The maximum possible bearing OD results from the intermeshing of two screws in the case of twin screw extruders. In the process, the crest diameter of one screw contacts the root diameter of the other screw. The resulting tight center distance and the output shaft near the
tandem bearing limit the radial design space. The length of a tandem bearing is normally not a crucial factor in bearing selection. For this limited envelope, tandem bearings are available in the 31.5 to 900 mm OD range.
The required calculated rating life under operating load and speed is generally between 20,000 and 40,000 hours for extruder gearboxes. Smaller gearboxes such as those used in extruders for
laboratory applications have shorter life requirements. Here, a value of 5,000 hour is sufficient. Another factor to consider in bearing selection is the maximum screw pressure. Due to the deformation of the components and the resulting stresses, a maximum permissible axial load Fa max may not be exceeded. The value for Fa max, the dynamic load rating C as well as the static load rating C0 can usually be found in the tandem bearing delivery drawing.

Tandem bearings offer an optimum solution wherever the
following requirements apply:
■ small radial design envelope
■ high axial forces
■ long operating life
■ low frictional energy.
Tandem bearings have proven effective principally in gearboxes
for single and twin screw extruders in the rubber and plastics
industry.
Other possible applications include:
■ deep hole drilling equipment
■ friction welding machines.