|
|
|
|
 |
|
|
 Products New Bearing Technologies |
|
| Hi-TF Bearings / Characteristics |
|
|
|
- Remarkably superior life under contaminated lubrication conditions.
- Life longer than that of standard bearings when in clean environment.
- Reduced wear.
- Higher gripping resistance.
- Dimensional stability up to 140°C.
Due to the arrested austenite, the mark generated on the race and on the rolling elements by the presence of impurities is minimized and the tension concentration generated around the teeth formed decreases. This HTF bearing property increases bearing fatigue life.
Tension concentration around the tooth is expressed by the equation [P/P0 a (r/c)-0,24]. The meaning of the unknown quantities and the illustration of an arbitrary mark is shown in Figures 1 and 2.
As exemplified, the concentration ratio (P/P0) is inversally proportionate to (r/c), that is, the larger the radius (lower depth) and the lower the mark size (c), the lower the tension concentration on this mark. This property is attributed to the arrested austenite. This control was named TF Technology (forerunner of HTF bearings). The relation between r/c values and the level of arrested austenite is shown in figure 3.
The arrested austenite is an instable structure at ambient temperature and is obtained through specific thermal treatment only. Its main property is high tenacity, which is the capacity to absorb energy. However, it has a structure with hardness below steel standards for bearings. For that reason, new materials and thermal treatments were developed, combining high tenacity and strong hardness. That originated the HTF (fig. 5).
Tests with the L44649/10 bearing are listed below (fig. 6), which demonstrates the superiority in terms of service life obtained with the Hi-TF bearings, when under contaminated lubrication conditions.
Even in optimum lubrication conditions, Hi-TF bearings excel, as demonstrated by the 6206 bearing (fig. 7).
In face of these tests, the supremacy of Hi-TF bearings is evident, especially in contaminated lubrication environments (fig. 8).
Below we observe that, in deficient lubrication conditions, that is, protective film formation is insufficient, the contact between the rolling elements and the races is more effective. Hi-TF bearings present an extraordinary performance (fig. 9). The TRIANGLE parameter represents the ratio between the oil film width and the surface rugosity.
In addition to increasing the bearing life under contaminated lubrication conditions, another factor that contributes to the superiority of the Hi-TF bearing is its greater wear and gripping resistance (fig. 10).
This technology is used in small and medium sized bearings, and it gives the bearing a 62 to 63 HRC hardness. These bearings have manganese as alloy element.
|
|
|
|
 |
| Self-aligning roller bearings. |
 |
|
 |
| A NSK relationship program with its Distributors. |
|
|
|
|
|
|
|
|
