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 small cross-section, the bearing still has a high 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 journal surface and shell hole surface 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 shaft or shell hole raceway surface should be similar to the raceway of the bearing ring. This type of bearing can only withstand radial loads.

type

In addition to the bearings listed in the catalog, they can be used for general engineering purposes, such as open stamped outer ring needle roller bearings .

(1) , closed stamped outer ring needle roller bearings

(2) , needle roller bearings with inner rings

(3) and needle roller bearings without inner rings/without inner rings and cages

(4) , full needle roller bearings with and without cages.

Install

Installing a fully loaded needle roller bearing is usually done using an auxiliary sleeve. At this point, the auxiliary roller or sleeve supports the needle to prevent it from falling out. The journal lifts the needle with its own chamfer, and as the needle bearing slowly moves inward on the journal, the auxiliary roller or sleeve slowly exits until it is installed in the working position. The outer diameter of the auxiliary roller and auxiliary sleeve should be 0.1-0.3mm smaller than the shaft diameter.

When installing, first apply lubricating grease to the inner surface of the outer ring of the bearing, and place the roller needle tightly against the inner surface (there should be a gap when placing the last roller needle). Then, push the auxiliary roller or sleeve that replaces the journal or bearing inner ring into the outer ring hole, and align its end face with the installation shaft end face or the bearing inner ring end face that has already been installed on the shaft. Then, use a press or hammer to tap and apply pressure. Needle roller bearings can also be installed in this way by applying a thin layer of lubricating oil to the outer diameter of the auxiliary sleeve, inserting it into the outer ring of the bearing, forming an annular hole between the auxiliary sleeve and the outer ring of the bearing, and then installing a needle in the annular hole.

 After installing the needle roller, use the working shaft to push out the auxiliary sleeve. For needle roller bearings without inner or outer rings, a thin layer of lubricating grease can be applied to the rolling surface of the shaft or housing hole before installation, and the needle rollers can be tightly pressed onto the lubricating grease at the installation site in sequence.

When placing the last needle roller, there should be a gap, and the size of the gap should be 0.5mm on the circumference of the needle roller bearing. Do not forcefully squeeze the last roller needle into it, or install one less roller needle, because during forceful extrusion, the bearing will become stuck and cannot rotate; When installing less, excessive clearance can easily cause the rolling needle to twist and break during bearing operation. For needle bearing with only stamped outer ring, due to the thin outer ring wall, the needle bearing needs to be installed by tapping with a hammer and should be pressed in using a press. Because the pressure is uneven when struck by a hammer, it is easy to cause local deformation of the outer ring of the needle bearing.