SFERAX

17 Technical Information Fitting Instructions When fitting SFERAX ball bea- rings, extreme care should be taken (just as for radial bea- rings). For best results and to ensure precise fitting, the bea- ring should be pressed into the housing using a mandrel 0,1 mm smaller than the housing bore. It should be square to the bearing and in contact with the outer housing only (see illustration 1). The ball bearing can be held in place by being slightly tightened without hold or left to slide freely and fastened by screw nut, circlips, end cover, etc. It can also be bonded (see tolerances p. 22). _____________________________ Illus. 1 _____________________________ Where two ball bearings are to be used in tandem, it is recom- mended that the shaft be inser- ted into the ball bearings prior to bonding in place. Working Life More than 50 years of experien- ce in the manufacture and appli- cation of SFERAX ball bearings testifies to our claim that linear ball bearings in general, and SFERAX in particular, have contributed directly to the impro- ved performance and longer life of all types of high technology machines, with reduced energy consumption. Details on SFERAX ball-bearing installations and working life calculations are provided below. For well-installed elements that are submitted to normal use and carefully protected from dust and contamination, the values obtained are in fact below reali- ty ; a large safety margin has been allowed. Nevertheless, we would remind users that ball bearings are fragile elements requiring due care. The following rules should always apply : – A high degree of cleanliness – Avoidance of shock loads – Correct alignment of the ball bearing and shaft – Adequate lubrication – Correct loading of the ball bearing and shaft. – Appropriate temperature – Careful adjustment (bearing and shaft) The shaft deflection should always be calculated, as this may dictate that a larger diame- ter bearing is required (see page 60) . It is easily understandable that a shaft bent under the load is not supported by all the balls of the bearing. Normally a deflection larger than 0,01 mm with respect to the length of the supporting balls is unacceptable, unless the ball bearing is strongly overdimensioned for the actual load.