High-speed spindle bearings in X-life quality
Three fundamental spindle bearing designs have established themselves on the market, and these can be categorized according to the size of the rolling elements: Large-ball series, small-ball series, and designs with medium-size balls. With its new M, HCM, and VCM series of X-life High-Speed spindle bearings, Schaeffler has optimally combined the kinematic suitability for high speeds of existing small-ball high-speed series with the robustness and load carrying capacity of large-ball bearings by matching the ball size, osculation, and radial internal clearance together in a targeted manner. Important development objectives for the X-life High-Speed series also included an internal construction with particularly optimized friction behavior and a high tolerance towards rapidly changing thermal operating conditions such as those that frequently occur in motor spindles. This optimized construction greatly reduces the rise in bearing preload caused by influencing factors such as interference between the bore and the bearing, high speeds, and large temperature gradients between the shaft and housing. Background: The increase in preload is only desirable within certain limits, because parameters such as friction and heat generation in the rolling contact also dramatically increase at the same time, which limits the maximum permissible speed. The new FAG spindle bearing series will be offered in three different versions.
“M” version – cost-effective and robust
The balls and rings of M-series X-life High-Speed spindle bearings are manufactured from the proven 100Cr6 rolling bearing steel. This version provides a high-performance, cost-effective bearing solution for motor spindles. “HCM” version – outstanding productivity thanks to high performance and suitability for high speeds HCM-type X-life High-Speed spindle bearings are equipped with ceramic balls and rings made from 100Cr6 rolling bearing steel. Thanks to their high performance capability and suitability for very high speeds, HCM spindle bearings allow the performance of motor spindles to be increased even further.
“VCM” version – new degrees of freedom in motor spindle design
Spindle bearings in the VCM X-life High-Speed series also feature balls made from ceramic material, but with bearing rings made from the newly-developed Vacrodur high-performance material. This steel is characterized by its extremely high load carrying capacity, wear resistance, and very high temperature resistance – particularly in the case of abnormal lubrication conditions such as insufficient lubrication or contamination. VCM-type spindle bearings specifically open up entirely new levels of freedom when designing motor spindles compared to conventional spindle bearings.
Bearing configurations for every application
The M, HCM, and VCM series of X-life High-Speed spindle bearings are available for dimension series 70 and 719 and with nominal contact angles of 17 and 25 degrees. What is more, three different pretension options are also available. As is the standard practice for spindle bearings, these bearings are delivered with universal adjustment, which means that any desired arrangement of individual bearings and sets is possible. The spindle bearings can be designed in both open and sealed versions as well as a “direct lube” version with lubrication holes and seals in the outer ring. Available bore diameters range from 25 to 130 mm, and 50 to 80 mm will initially be available for sealed versions. Further diameter ranges are also planned in subsequent release stages.
With these new X-life High-Speed spindle bearings, spindle manufacturers can significantly increase the mechanical and thermal load carrying capacity of their existing product series without changes to the design. The new series opens up entirely new levels of design freedom thanks to its high-performance VCM version.