The main challenge is to extend wheelset bearing maintenance intervals in the high-speed market with SKF identifying that a continuous and sufficient supply of oil from the grease to the rolling contact was required for the whole life of the bearing. Failure to do this means surface-initiated fatigue is likely, therefore increasing the risk of bearing failure.
A cylindrical roller bearing unit (CRU) has been developed that improves the cage design and contact between the roller face and ring flange. This results in a very stable low bearing temperature which has a direct impact on the lifespan of the grease.
Tapered bearing units (TBU) reduce the friction in rolling contact therefore leading to lower bearing temperature and longer grease life. A new grease retainer increases the quantity of the grease in the bearing while also preventing grease overflow. There is also a new centrifugal lip (CL) seal which acts as a contact seal at lower speeds and turns into a labyrinth seal with zero friction at higher speeds.
SKF has developed innovations to optimise the roller-raceway geometry, reduce the roughness of the raceway surface finish, and improve the contact between the roller end and face-flange.
