Needle Roller Bearing and Cage Design Criteria and Uses

The design is simple as the only components are the needles and the cage. Needle Roller and Cage Assemblies are perfect for use in small envelope designs. This type of bearing is considered a direct bearing arrangement where the shaft and housing are used as the raceways for the needle rolling element. The Needle Roller and Cage Assembly have no inner or outer ring, so they are incorporated with the shaft and housing.

Components of Needle Roller Bearings

The shaft and housing are rolling raceways, so they must be carefully designed and toleranced to a high accuracy to be used when high radial runout is needed. Other considerations for optimal design include radial clearance, the function of the proper shaft and housing tolerances, and the needle roller grade. Needle roller and cage assemblies must be located axially using snap rings or abutment shoulders.

Needle roller and cage assemblies may be single or double row with a cage and needle rollers. The radial section height matches the diameter of the needle rollers, so designing with small envelopes is possible.

Radial needle roller and cage assemblies are designed to support high radial loads and operate at high speeds. Needle Roller Cage bearings have the load carrying capacity advantages of full complement needle roller bearings but with the speed advantages of a caged bearing. Other advantages for using Needle roller cage and cage type assemblies are ease of installation, rigid bearing arrangements, and their economic value and cost effectiveness.

INA needle roller and cage assemblies

• INA series KZK Needle roller and cage assemblies for crank pins

INA Needle roller and cage assemblies for crank pins are externally guided. Externally guided means the connecting rod bore guides the cage. The radial movement of the cage relative to the connecting rod bore and the rolling elements is very small. The cages are made from quenched and tempered steel, have good wear resistance, high strength, and large guidance surfaces designed for optimum lubrication.

• INA series KBK Needle roller and cage assemblies for piston pins

The needle roller and cage assemblies for piston pins are internally guided, which means that the piston pin guides the cage. Designed with a small radial internal clearance, tilting of the connecting rod is minimally reduced. The KBK INA series bearings support high-frequency oscillating loads. The INA KBK series bearings are available in many of the piston pin diameters with different widths. The INA KBK series have low-wear steel cages that are case hardened or quenched and tempered for long wear.

• INA series KZK Needle roller and cage assemblies for planetary gear bearing arrangements

Needle roller and cage assemblies that are designed into planetary gearing applications operate at remarkably high speeds. In planetary automatic gearbox applications, the bearing is subject to high centrifugal and acceleration forces, where the cage is then subject to higher stresses than normal.

Design of Raceways

Raceways for bearings without an inner and/or outer ring are crucial for proper operation, so the following link to INA must be used to correctly define the shaft and bore tolerances needed.

When the needle roller and cage assemblies run directly on the shaft and/or in the housing bore, then the raceway for the rolling elements on the shaft and in the housing must be produced as a rolling bearing raceway (hardened and ground). The surface hardness of the raceways must be 670 HV to 840 HV, and the hardening depth CHD or SHD must be sufficiently large.

For Needle roller and cage bearing selection and purchase visit the PIB catalog.