Seiko develops long-life bearings for rolling mills

Seiko has developed 'long-life sealed backup roll bearings' for Sendzimir rolling mills. By improving the lubricity of the seal and using special steel with long life, it can adapt to the high-speed operation of the rolling mill. Sendzimir rolling mills are mainly used for rolling steels with high hardness, such as electromagnetic steel sheets and stainless steel sheets, which are difficult to roll. With the electrification of machinery, the increase in the production of hybrid vehicles, and the addition of power stations and substations in the process of improving infrastructure in emerging market countries, the demand for electromagnetic steel plates has increased rapidly, and the operating speed of Sendzimir mills has also continued to increase. Most of the backup roll bearings used in high-speed Sendzimir mills are exposed to a large amount of low-viscosity rolling oil with poor lubricity. Therefore, oil mist lubrication is used for bearing lubrication. However, in order to stably provide oil mist lubrication in the conventional bearings, the oil mist is not passed through the seal, but is discharged from the small hole, so the lubrication and durability of the seal are insufficient during high-speed operation. For this reason, the new bearing adopts a structure in which the supplied oil mist first passes through the seal and then is discharged to the outside of the bearing, thereby improving the lubricity of the seal. In addition, the integration of the seal and the mandrel reduces the number of parts, and improves the accuracy of the parts and reduces the error in the amount of pressurization of the seal, thereby optimizing the contact surface of the seal. With the above measures, not only the wear of the seal is reduced, but also the discharge of oil mist is made more stable, and the rolling oil is prevented from immersing in the bearing. In addition, the bearing also removes the O-ring at the installation part of the slinger, and integrates the O-ring with the slinger by covering the slinger with rubber. Replacement work is also easier because the number of parts is reduced. In addition, this time, 'SAC steel' developed by the company is also used. High durability even if foreign matter enters, resulting in a long service life.