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 during installation, and the needle rollers can be sequentially pressed against the lubricating grease at the installation site. There should be a gap when placing the last needle roller, and the size of the gap should be zero on the circumference of the needle roller bearing. 5mm is suitable. Never forcefully insert the last needle roller or install one less needle roller, as the bearing may get stuck and unable to rotate during the process; When installed sparingly, excessive clearance can easily cause the rolling pins to twist and break during bearing operation.

It is specifically pointed out here that for needle roller bearings with only stamped outer rings, due to the thin outer ring wall, it is best not to use a hammer to install them, but to use a press to press them in. Because the pressure is uneven when struck with a hammer, it is easy to cause local deformation of the outer ring of the needle roller bearing.

Installing fully loaded needle roller bearings is usually done using auxiliary sleeves. At this point, the auxiliary roller or auxiliary sleeve supports the rolling needle to prevent it from falling out. The shaft neck lifts the rolling needle with its own chamfer, and as the rolling needle bearing slowly moves inward on the shaft neck, the auxiliary roller or auxiliary 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 bearing outer ring, and place the rolling needle tightly against the inner surface (leaving a gap when placing the last rolling needle). Then, push the auxiliary roller or auxiliary sleeve that replaces the shaft neck 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 already installed on the shaft. Finally, use a press or hammer to 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, so that the auxiliary sleeve and the outer ring of the bearing form an annular hole, and then installing the needle roller into the annular hole. After installing the needle roller, use the working shaft to push out the auxiliary sleeve.