All SKF angular contact thrust ball bearings for screw drives are designed for low friction operation. The frictional moment depends on the preload, rotational speed, seals and quantity of lubricant in the bearing set. The starting torque is typically double the frictional moment.
Single direction bearings
Guideline values for the frictional moment of single direction bearings are listed in the product table
and apply to unmounted bearing sets with two bearings arranged back-to-back or face-to-face that will operate at low speeds.
Bearing sets consisting of three or four bearings have a higher frictional moment than sets with two bearings. The frictional moment for these bearing sets is obtained by multiplying the values in the product table by a factor provided in table 1.
Double direction bearings
Guideline values for the frictional moment of double direction bearings are listed in the relevant product tables (→ BEAS series
Guideline values for the frictional moment of cartridge units are listed in the product table
and apply to unmounted bearings that will operate at low speeds.