How to Install Needle Roller Bearings?

Ⅰ. Understanding 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. Although it has 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, and its inner diameter size and load capacity are the same as other types of bearings, and its outer diameter is the smallest, especially suitable for support structures with limited radial installation dimensions. Needle roller bearings have a large load-carrying capacity and are suitable for supporting structures with limited installation dimensions. The journal surface is hardened as a rolling surface, and the bearing is fitted into the seat hole by press-fitting, so there is no need to perform axial positioning on it.

Ⅱ. The installation of needle roller bearings

1. Install full complement needle roller bearings, generally using auxiliary sleeves. The auxiliary roller or auxiliary sleeve supports the needle roller so that the needle roller does not fall out. The journal lifts the needle roller with its own chamfer. As the needle roller bearing moves inward on the journal slowly, the auxiliary roller or auxiliary sleeve The cylinder will withdraw slowly until it is installed to the working position. The outer diameter of the auxiliary roller and the auxiliary sleeve should be 0.1~0.3mm smaller than the shaft diameter.

2. The needle roller bearing can also be installed in this way, that is, the outer diameter of the auxiliary sleeve is coated with a thin layer of lubricating oil, and inserted 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 the needle roller is installed in the annular hole. After the needle roller is installed, use the working shaft to push the auxiliary sleeve out.

3. For needle roller bearings without inner ring or outer ring, when installing, first apply a thin layer of grease to the rolling surface of the shaft or housing hole, and stick the needle rollers to the grease on the installation part in turn , There should be a gap when pasting the last needle roller. The size of the gap should be 0.5mm on the circumference of the needle roller bearing.

4. For needle roller bearings with only stamped outer rings, because the outer ring wall is very thin, do not use a hammer to install it, but use a press to press it in, because when the hammer is tapped, the pressure is uneven, and it is easy to make the outer ring of the needle roller bearing The circle produces local deformation.

When you know how to install needle roller bearings, you will be able to do it well when doing this work. When to use a socket? Where to apply lube? Can it be hit with a hammer? How to install the needle, etc., all these will no longer be a problem after you understand the relevant introduction above, you can easily handle it. Of course, practice is the most important thing. Only by doing it can you really learn from it.

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