Preload as required
A bearing´s preload determines both the performance of the spindle, as well as the quality of the product. Heavy preloads increase the rigidity of the bearings set; light preloads enable higher operating speeds. Besides the usual classes of preload (L-M-S) UKF can also, upon request, prepare the bearings with preloads meeting specific requirements in Fv[N]. For example:"Super Light" with its value lower than standard "Light".
For especially challenging applications, bearings can be factory screened, such that all bearings of a specific lot have no more than 2...3 µm variation in bore diameter. The point of maximum runout (ring´s eccentricity), along with the size variation (actual measured deviation), is marked on the bearing.
Special Precision Classes
Spindle Bearings and Bearing Cartridges are manufactured in Precision Classes from UKF I (Standard) to UKF 0, or even higher. Axial runouts of the inner ring (which is the rotating part in most cases), to < 1 µm, (bore d < 50 mm), in accordance with UKF precision "HQ", are also available. For larger bore bearings, consult the factory.
Lubrication with high performance special greases
As the result of many years experience, greases like ISOFLEX LDS 18 Special A and ISOFLEX NBU 15 for Spindle Bearings, have found to be well suited for our Angular Contact Ball Bearings. (Messrs. Klüber: www.klueber.com). For very high RPM applications, especially with Hybrid Bearings, we suggest TURMOGREASE Highspeed L252 (Messrs. Lubcon: www.lubcon.com). But other qualified bearing greases, especially greases of NLG class 3 (for lower speed) and class 2 (for medium speed), with a penetration of 220...295, are usable.
Design „XH" of CRONIDEX®-Steel
Developed as corrosion-resistant steel for aerospace applications, this alloy´s high strength has also proven itself to be ideal for Spindle Bearings. Compounded with carbon, molybdenum, and increased levels of nitrogen, it achieves a hardness comparable to Bearing Steel 100Cr6,> 58 HRc, but with higher fatigue and wear resistance.
For Spindle Bearings, this means:
Certain bearings are available with optional, factory-installed shields. These bearings are also pre-lubricated with the appropriate type and quantity of grease, and are ready for installation. In general, these bearings need no additional lubricants during their service life. Shields are provided on both sides, and are fixed in the Outer Ring. The shields are made of a special, exceptionally stabile plastic, which is resistant to most lubricants and against temperatures up to 80° (180°F). The shields are non-contacting with the Inner Ring, and do not add any friction load to the bearing. Shield designation: „2Z"