Introduction to Two Kinds of Needle Roller Bearings
Needle roller bearings are roller bearings with cylindrical rollers that are thin and long relative to their diameter. Such rollers are called needle rollers. Despite having a smaller cross section, the bearing still has a high load carrying capacity. Needle roller bearings are equipped with thin and long rollers, so the radial structure is compact. When its inner diameter and load capacity are the same as other types of bearings, the outer diameter is the smallest, which is especially suitable for supporting structures with limited radial installation dimensions.
Depending on the application, bearings without inner rings or needle roller and cage assemblies can be selected. At this time, the journal surface and the housing hole surface matched with the bearing directly serve as the inner and outer rolling surfaces of the bearing. In order to ensure that the load capacity and running performance are the same as those of bearings with rings, the hardness, machining accuracy and surface quality of the raceway surface of the shaft or housing hole should be similar to those of the raceway of the bearing ring. This type of bearing can only bear radial loads.
1. Combined needle roller bearing
Combined needle roller bearing is a bearing unit which is composed of radial needle roller bearing and thrust bearing components. It has compact structure, small volume, high rotation precision, and can bear a certain axial load while bearing a high radial load. And the product structure is diverse, adaptable and easy to install. Combined needle roller bearings are widely used in machine tools, metallurgical machinery, textile machinery and printing machinery and other mechanical equipment, and can make the mechanical system design very compact and flexible.
2. Thrust needle roller bearings
Thrust bearings consist of thrust cage assemblies with needle or cylindrical rollers or balls and thrust washers. Needle rollers and cylindrical rollers are held and guided by thrust cages. When used with different series of thrust bearing washers, many different combinations of bearing configurations are available. Due to the selection of high-precision cylindrical rollers (needle rollers) to increase the contact length, this bearing can obtain high load capacity and high rigidity in a small space. Another advantage is that if the surface of the adjacent part is suitable for the raceway surface, the washer can be omitted, which can make the design compact. The needle rollers used in thrust needle roller bearings and cylindrical roller thrust bearings and the cylindrical surface of cylindrical roller are modified surfaces, which can reduce edge stress and improve service life.