SFERAX

16 Technical Information Design The basic SFERAX ball bearing is composed of : – A housing made of ball bearing steel, machined, hardened to 65 HRC +0 -3, ground and lapped except the B quality, which is only precision-ground. – Brass turned and milled ball tray or in polyamid for the GBP execution. – Precision steel balls. – Steel locking rings and plastic control rings injected after assembling. Design changes in the different types of SFERAX ball bearings are described under the appropriate headings. Precision Grades (see table page 22) B = medium ................................... (red) BA = medium improved ................... A = good ................................... (green) XA = very good ........................... (blue) ZA = high precision ............. (black) Friction Coefficient Approx. 0,002 Reduced friction allows heavy loads to be shifted longitudinally with a minimum expenditure of power, hence energy. Dynamic Load On request. Preload Depending on the application and the dimension, from 0,002 to 0,02 mm on the shaft diameter. Maximum Speed of Movement For Standard SFERAX 5 m/sec. In case of ball-bearing move- ment, the speed at the end of the stroke must be decreased. Admitted Acceleration Standard SFERAX 100 m/sec 2 Special SFERAX 150 m/sec 2 Recommendation For rapid acceleration/decele- ration, we recommend using three dowel pins at 120° angle at either end. Ball bearings with an inner diameter of 100 mm or more are fitted with 3 dowel pins as standard. Allowed Temperatures For Standard SFERAX - 30° + 80°C. For Special SFERAX, type BL - 30° + 140°C. For SFERAX type HT, SMX and COMPACT - 30° +200° C. Lubrication – Thin bodied oil - for high speeds – Dry if necessary Max. speed 1 to 2 m/min. (without seal) – Lithium-based grease. For instance, for horizontal applications and medium speeds. Choice of viscosity depends on speed ; the higher the speed is, the lower the viscosity should be. Cleaning Rectified benzine Petroleum Compressed air Protection SFERAX ball bearings are delivered with a corrosion- preventive coating.