Tandem roller bearing F-213621.T6AR for extruder gearbox

Tandem roller bearing F-213621.T6AR for extruder gearbox

F-213621.T6AR BEARINGS Information:

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.

How to Mount Tandem Bearings:

Tandem bearings are mounted with a loose F7 fit for the housing and f6 for the
tandem bearing shaft. A loose fit is necessary to allow the axial shifting (deflection) of the washers, rings and sleeves. The seating surface of the adjacent structure (housing and shaft) should be designed to have a perpendicularity tolerance to DIN ISO 1101 and qualities IT4 to IT7
(depending on the diameter range). For the mating structure, care should also be taken to ensure that the contact diameter indicated on the delivery drawing is maintained. The contact diameter
(support diameter) for the shaft shoulder may not be lower than the diameter indicated, and the contact diameter for the housing must not be exceeded. Insufficient support will not only cause an unequal load distribution but also an increased washer deformation (washers GS 0 and WS 0), which in turn will result in increased strain on the components.

The tandem design allows the use of a high thrust capacity bearing in a small area. It was originally designed for a rotary swivel used on an oil drilling rig. Later these bearings were adopted by plastics and rubber manufacturers for use in single screw extruders utilizing 2 and 3 stage bearings. The tandem design enabled the extruder manufacturers to
increase the output of the machines without increasing the size of the
gearboxes.This allowed their customers to have a higher output machine without taking up more floor space. These bearings are used in twin screw extruders as well.Twin screw extruders have two parallel shafts very close to each other, making the use of the tandem thrust bearing essential. Some twin screw extruder designs use eight stage tandem thrust bearings.We manufacture two, three, four, six and eight stage bearings in both inch and metric
series. Bore sizes range from about 1 to 22 inches with corresponding outside diameters ranging from 3.5 to 42 inches. tandem thrust bearings are supplied to original equipment manufacturers and the aftermarket.