NTN Cylindrical Roller Bearing

Cylindrical roller bearings can be made of different materials. NTN has unique processes to increase bearing life. These include Austenite Strengthening, a special heat treatment that alters roller surface chemistry and yields compressive stresses, increasing bearing life by 1.5 times. NTN also uses its proprietary High Lubrication (HL) surface treatment, a micro-pitting process that channels oil to the specific places it's needed.

Metallographic structure of the damaged area of a cylindrical roller bearing

Skidding damage of cylindrical roller bearings can be observed by looking at the metallographic structure of the damaged area. This damage can be characterized by the presence of spalling pits that have a diameter of about 13 um. Additionally, the damaged area can be characterized by the presence of microcracks that run along the direction of rolling. This type of wear is usually caused by the excessive radial force of the pulley at the dynamic end. The resulting abnormal local stress can cause serious damage to the cage, a serious burn of the roller, and the generation of noise and vibration.

Skidding damage law

Cylindrical roller bearings suffer skidding damage due to sudden acceleration and deceleration of a rotating assembly. This type of wear is reflected on the surfaces of the inner ring rollers and raceways. The maximum wear depth of these surfaces is 8 um.

Performance

The performance of a cylindrical roller bearing is influenced by the cage mass center whirl orbit. This orbit is a reflection of the cage stability and wear. An orbit with constant whirl speed and radius is considered to be stable. When the cage whirl orbit is a circle with a uniform mass center, then the cage whirl is stable and its wear is less.