Needle bearing is a roller bearing with cylindrical rollers, which are both thin and long relative to their diameter. This type of roller is called a rolling needle. Despite having a smaller cross-section, the bearing still has a higher load bearing capacity. Needle roller bearings are equipped with thin and long rollers (roller diameter D ≤ 5mm, L/D ≥ 2.5, L is the length of the roller), so the radial structure is compact. When the inner diameter size and load capacity are the same as other types of bearings, the outer diameter is the smallest, making them particularly suitable for support structures with limited radial installation dimensions.

According to different usage scenarios, bearings or needle and cage components without inner rings can be selected. At this time, the surface of the shaft neck and outer shell hole that match the bearing directly serve as the inner and outer rolling surfaces of the bearing. To ensure the same load capacity and operating performance as bearings with rings, the hardness, machining accuracy, and surface quality of the surface of the shaft or outer shell hole raceway should be similar to that of the bearing ring raceway. This type of bearing can only withstand radial loads.

Needle bearings are widely used in various mechanical equipment such as machine tools, metallurgical machinery, textile machinery, and printing machinery, and can make mechanical system design very compact and flexible.