Four rows of tapered roller bearings consisting of two inner ring components; An inner septum; The inner diameter of the inner ring and the shaft are designed as a clearance fit, and at the same time, the outer ring and the aperture are transitional fit. It can meet the requirements of quick loading and unloading on site. This type of bearing can bear large combined radial and axial force loads, and can be used separately on the roll system without positioning bearings. This feature is conducive to simplifying the structure and length of the roll system in the rolling mill design, and is mainly applied in Sanling Rishi in Japan. The German west mark; American I2s and Italian Mino and other single and continuous rolling equipment, at present domestic six-high mill roll system selection also presents a trend of four-row conical structure selection, especially continuous rolling equipment.

Although the four-row tapered bearing can achieve clearance fit and quick loading and unloading after it is installed in the bearing box, the installation requirements and the size, roughness and hardness of the matching parts have certain requirements, such as the following field problems:

1. Bearing end face contact roller shoulder wear subsidence and deep pits

2. Wear of shaft shoulder produces metal foreign matters

Comprehensive analysis of the reasons:

Analysis on the bearing shoulder sinking and its problems: because the bearing inner diameter and shaft diameter dimension are clearance fit, there is sliding friction during high-speed rotation, which is bound to cause wear of bearing inner ring end face and mating part end face. After assembly, there is an axial clearance of 0.5-1 mm (assembly process requirements) between the shoulder end face and the bearing inner ring end face, and the abnormal wear and subsidence of the shoulder is about 3 mm As a result, the axial clearance exceeds the required clearance, about 4mm. As the axial movement of the roller increases, the inner hole of the bearing cage may touch the outer diameter of the shoulder. If the shoulder is touched, the cage will be interfered, and the bearing will be burnt and locked at high speed.