The needle roller bearing cage assembly is a part of the needle roller bearing, which is used to separate the needle roller, maintain the symmetrical radial spacing of the needle roller, and in most cases, keep the bearings together. The cage may also provide lubrication by acting as a reservoir of lubricating oil or by providing a solid film through the cage material itself or the coating on the cage.

It is very important for the designer to choose the proper cage design for the application to realize the ideal life and performance of the bearing. When the holder swings like a hula hoop, it causes torque spike in the rotating assembly. The keeper should be tracked on a true circular plane concentric with the pitch diameter of the ball.

When the axial load is applied to the static bearing whose shaft is in horizontal mode, the needle rollers fall to a position where they are not evenly spaced before the load is applied. When an axial load is applied, it compresses the needle between the inner and outer raceways. Now the balls are firmly held at unequal intervals, and they cause the retainers to engage.

This combination is referred to as "holder suspend.". Once the bearing rotation starts, the retainer is stressed, and some balls may slip, causing damage, leading to premature failure of the bearing. The installation site shall be away from the machine tool, grinder and other mechanical equipment for a certain distance; the site shall be cleaned and kept dry and clean frequently to prevent iron dust, sand, dust and moisture from entering the needle bearing.

Check whether the model and size of needle bearing meet the installation requirements, and select the appropriate assembly method according to the structural characteristics of needle bearing and the matching parts, and prepare the tools and measuring tools for installation. The commonly used installation tools are hammer, copper rod, sleeve, special base plate, screw mosquito clamp, press, etc., with vernier caliper, micrometer, dial indicator, etc.