Q: What does the "NoWear" mark on the bearing mean?
A: "NoWear" translates into Chinese as "lossless", which literally means a durable lossless bearing, and is also figuratively defined as a bearing that never wears out.
In some advanced and high-end applications, some equipment has higher requirements for bearing performance, especially equipment that needs to operate under extreme conditions, such as adhesion, wear, poor lubrication, sudden load changes, low loads or high temperatures. In order to meet these unconventional working conditions, SKF Bearings has developed a special bearing with a low-friction ceramic coating on the internal contact surface. , this coating can be applied to the rolling elements or inner ring raceway of the bearing.
NoWear coating is a wear-resistant carbon coating that can be machined on the rolling elements and inner ring raceway of the bearing
20 (model suffix L7DA) or only on the rolling elements (model suffix L5DA). It uses a physical vapor deposition process to machine the wear-resistant carbon coating onto the surface of the bearing, with a coating thickness ranging from 1 to 3 microns, depending on the bearing size. The hardness of the coating is 1200HV10.
There are currently two coating structures for this type of bearing, namely "L5DA" and "L7DA". L5DA bearings are relatively common, and their low-friction coating is machined onto the rolling elements of the bearing, suitable for medium loads and below, vibration or reciprocating conditions; while L7DA bearings, the low-friction coating is machined on the rolling element surface and the inner ring raceway of the bearing, suitable for heavy loads or special conditions with high wear resistance.
Such NoWear coated bearings can achieve longer service life in high speed, light load applications.
For grease-lubricated bearings operating at speeds close to or exceeding the permissible speed, or at high temperatures that damage the grease service life, the use of NoWear coating can extend the relubrication interval. If you want to extend the service life of bearings in heavily loaded applications where lubrication is close to insufficient, NoWear coating is a good solution. However, NoWear coating itself cannot prevent spalling caused by constant heavy loads. Because under heavy loads, the part below the surface, that is, the bearing steel under the coating, is subject to the greatest shear stress and therefore still has the characteristics of ordinary bearing steel.
In order to have the adaptability to ordinary bearings, the tolerances of NoWear never wear bearings are the same as those of ordinary bearings in terms of size, clearance and load, which greatly increases the application effect of this bearing.
