Ball bearings and bearing assemblies.

I. Introduction to the structure of needle roller bearings Needle roller bearings are roller bearings with cylindrical rollers. Although the cross section is small, the bearings still have a high bearing capacity. Needle roller bearings are equipped with thin and long rollers (rollers The diameter of the roller is D≤5mm, /D≥2.5, which is the length of the roller.) The radial structure is compact. The inner diameter and bearing capacity are the same as those of other types of bearings.

The outer diameter is smaller. It is especially suitable for supporting structures with limited radial installation size. . 2. Needle bearing components Auxiliary sleeves are usually used to install full complement Tapered Roller Bearing needle bearings. The outer diameter of the auxiliary roller and auxiliary sleeve should be 0.1-0.3mm smaller than the shaft diameter. Needle bearings can use bearings without inner rings or needle and cage assemblies. The surface of the journal and the hole of the housing matched with the bearing are directly used as the inner and outer rolling surfaces of the bearing to ensure the bearing capacity and running performance.

As with the ring bearing, the hardness, machining accuracy and surface quality of the raceway surface of the shaft or bearing hole should be similar to the raceway of the bearing ring. At this time, the auxiliary roller or auxiliary sleeve holds the needle without dropping the needle, and the journal pinches the needle with its own chamfer. When the needle roller bearing moves slowly inward on the journal bearing, the auxiliary roller or auxiliary sleeve will slowly withdraw until it is placed in the working position. Common failures of needle roller bearings (1) Bearings are difficult to rotate and generate heat; (2) strange noises in bearing operation; (3) bearings vibrate; (4) inner ring spalling; (5) outer ring spalling And cracking; (6) indentation in bearing raceways and rolling elements.