Press Release Summary:
Produced with minimal peak roughness values on raceway surfaces to provide optimized stress concentrations, X-Life(TM) bearings feature cylindrical rolling elements that support forces along contact lines and can handle dynamic loads up to 260 kN. Available cage types include pressed steel, profile milled brass cage, one-piece polyamide (plastic), polyamide segmented, machined brass, brass disk separator, and 2-piece brass riveted.
Original Press Release:
X-Life(TM) Cylindrical Roller Bearings From INA/FAG Offer Extended Life and Increased Savings
Improvement of 18% in dynamic load rating and 70% increase in nominal rating life
DANBURY, CT, February 8, 2006 - INA/FAG has used its research capabilities on raceway surface stress concentrations and its expertise in cage design to produce X-Life(TM) Cylindrical Roller Bearings, achieving increased load carrying capacities and extended life. The changes in surface quality have meant an average improvement of 18% in dynamic load rating and an average increase in nominal rating life of 70%.
The achievable life value of these bearings is heavily influenced by the surface roughness of the contact areas (raceways and longitudinal roller surface). The characteristics of the new X-Life bearings include significantly reduced peak roughness values on a raceway surfaces providing optimized stress concentrations
The increased performance and associated economic potential of the new X-Life Cylindrical Roller bearings can best be illustrated by the example of series NJ219E.TVP2:
Dynamic Capacity: 220 kN
Dynamic Capacity: 260 kN
In a bearing application predominantly involving high radial loads, a cylindrical roller bearing is often the ideal choice. In this type of bearing, the rollers are guided between rigid shoulders on the raceways. The raceways and shoulders are part of the bearing rings, which are separated by the rollers. The cylindrical rolling elements support the forces not at contact points, as in a ball bearing, but along contact lines and can therefore support higher loads than ball bearings. The general principle is that the more load-carrying rollers, the higher the basic load rating. If very high loads are to be supported and speeds are relatively moderate, full complement cylindrical roller bearings (with a maximum roller count and no cage.) are recommended. Where other variables and conditions such as high speed play a role, a cylindrical roller bearing with a cage must be adopted. INA/FAG offers various types of cages, depending on the application requirements.
Advantages and Applications of Brass Cages
The X-Life series has been expanded to include two new cage designs - pressed steel cage and profile milled brass cage, in addition to the three traditional types of materials - polyamide, pressed steel and conventional machined brass.
The new INA/FAG one-piece brass cage offers a number of important benefits, including optimized roller contact on the cross piece; optimized roller retainment; and minimized weight with necessary component strength. Applications involving strong vibrations or high accelerations (for example planet gear bearing arrangements) benefit from the one-piece, rib-guided solid brass cage. The new X-Life cage runs at a lower temperature than the existing broached cage. Contact of the rollers against the crosspiece is still in the straight part of the profile, in other words still at a tangent to the circumference of the roller. In this way, it can be ensured that no radial force components occur that would promote friction. Furthermore, the reduced side wall height has a positive effect on lubrication and cage mass: there is a significant reduction in mass-dependent forces such as occur in the case of vibration or accelerations. The resulting improvement in lubricant flow also improves the operating temperature in the bearing.
Pressed Steel Cage as a Cost-effective Alternative
For applications requiring high temperature, good lubrication and high geometric stability of the cage, a bearing with a pressed steel cage is often most cost-effective. The X-Life pressed steel cage is characterized by precisely defined guidance surfaces on the crosspieces with which the rollers are in contact and therefore have very precise parallelism of the cross pieces. In the old design, the guidance surface for the roller on the crosspiece was affected by the stamped surface that had poorer surface quality. The contact running surfaces of the new cage are both flat and uniform.
The advantages of the new steel cage can be summarized as follow:
o The rim type shape of the cage gives considerably better oil and grease flow. With oil lubrication in particular, this can be a decisive feature, since oil flowing through the bearing can absorb heat and thus lead directly to lower bearing temperatures. The newly optimized pressed steel thickness also guarantees higher rigidity than the earlier variant.
o Special geometry of the snap fit edges gives secure retention of the roller set during assembly into the application without impairing lubricant supply to the functional surfaces.
o The very precise guidance of rollers by the cross pieces, both in the load zone and the unloaded zone, prevents skewing of the rolling elements and gives a considerable reduction in transverse forces.
o Further developments in production technology have resulted in optimum geometry of the crosspieces and the running of the rollers against the cage cross pieces. This results in precise roller guidance in the pitch circle. The improved osculation and favorable surface structure have a positive influence on lubricant film formation.
INA/FAG continues to offer the existing polyamide (plastic) one-piece cage, polyamide segmented cage, brass disk separator, two-piece brass riveted cage, and full complement designs in addition to the new cage types described above.
You can obtain additional information about X-Life Cylindrical Roller Bearings by visiting www.fag.com.