Q: Performance and structure of precision cylindrical roller bearings.

A: Precision cylindrical roller bearings are used in places with high precision requirements, such as machine tool spindles or printing machinery.

It has the advantages of high running accuracy, good rigidity, strong load-bearing capacity and high rotation speed.

There are many structures of precision cylindrical roller bearings with cages, including single-row bearings with size series 19 and 10, and double-row bearings with size series 30 and 49. In each diameter series, the inner diameter and outer diameter of single-row bearings and double-row bearings are the same.

The suffix of precision cylindrical roller bearings with tapered holes is K. The taper angle is 1:12. Since this tapered hole allows the bearing to adjust the radial clearance and preload of the bearing by axial offset at the corresponding tapered position of the shaft, this bearing is mainly used in the machine tool industry. The structure of single-row and double-row precision cylindrical roller bearings is shown in the figure below.

The rolling elements of precision cylindrical roller bearings are guided by the outer ring rib (NNU type) or the inner ring rib (N type and NN type). The NNU type rolling bearing system is highly rigid, but the load-bearing capacity is lower than that of the NN type. The outer ring of the precision double-row cylindrical roller is generally equipped with a lubrication groove and three evenly distributed lubrication holes. N, NN, and NNU precision cylindrical rollers can only bear radial loads. Cylindrical roller bearings require good alignment of the bore and shaft. Poor alignment will lead to a certain amount of forced rotation, which will increase the operating noise of the bearing and reduce its service life. Precision cylindrical roller bearings use ceramic rolling elements, which can have higher speeds and stronger system rigidity, and can reduce the bearing temperature rise. Improve the service life of the equipment. Hybrid ceramic precision cylindrical roller bearings have the highest speed, but this is at the expense of the rated static load of the bearing.