SFERAX

18 Technical Information Working Life We use the same formula for calculating the working life expectation of ball bearings of all qualities. Ball bearings with a higher level of precision have a much longer working life than those with wider tolerances, although the latter support more play. Table 1 below lists the hardness coefficient which is determined by the hardness of the shaft measured in Rockwell C. (page 20) The tables describing the dimen- sions and the characteristics of the ball bearings also include a factor Y , determined by the allo- wed static load. These first measurements allow you to obtain the fl factor according to the formula : fl = X • Y • P fl = coefficient of the working life expectation X = coefficient of shaft hardness Y = dynamic coefficient of the ball bearing P = load perpendicular to the ball bearing [Kp] Diagram 1, page 21 , gives us the working life expectation in metres. The working temperature influences the working life expectation and must be taken into consideration in the calcula- tion by the Z factor according to Table 2, page 20. The given formula is valid for a maximum deflection of 0,001 mm along the total length of the supporting balls. It is imperative not to use untempered hard-chrome shafts. In case of doubt, do not hesitate to consult us before starting a new combination. We are at your disposal for all information, and will not hesitate to advise against the use of the SFERAX ball bearings when the application is unsuitable.