Needle Roller Bearings

What is Needle Roller Bearings?

Needle roller bearings are roller bearings with cylindrical rollers. The rollers are thin and long relative to their diameter. This kind of roller is called a needle roller. Despite having 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 roller length), so The radial structure is compact, and its inner diameter and load capacity are the same as other types of bearings, and the outer diameter is the smallest. It is especially suitable for supporting structures with restricted radial installation dimensions.

According to different applications, bearings without an inner ring or needle roller and cage components can be selected. At this time, the journal surface and shell hole surface matching the bearing are directly used as the bearing’s inner and outer rolling surfaces to ensure the load capacity. Running performance, Same as the bearing with the ring, the hardness, machining accuracy, and surface quality of the raceway surface of the shaft or housing hole should be similar to the raceway of the bearing ring. This kind of bearing can only bear radial load.

Needle roller bearing types

There are a few styles of needle roller bearing you can choose from. Options can include single row, double row, solid, or split cage. Other needles bearing roller specifications have:

• Metric or inch series

• Open or closed-end

• Open, single seal (U) or double-sealed design (UU)

• Relubrication holes are available on larger sizes (above 10 mm bore)

• Full complement of rollers

• Special internal clearance and unique heat treatments

• A limited range is offered in AISI 440C Stainless Steel

Needle roller bearing application

The structure of needle roller bearings is diverse, and the scope of application is also different. The details are as follows:

Needle roller bearings withdrew outer rings. This type of bearing has two types: perforated type and sealed type. The drawn cup needle roller bearing has no inner circle, and the needle directly contacts the surface of the shaft. Therefore, the machining accuracy and heat treatment hardness of the post should be the same as the inner ring of the bearing.

Scope of application: Drawn cup needle roller bearings with cages are suitable for high-speed and heavy-duty applications and are primarily used in gearboxes for machine tools, automobiles, and motorcycles, or textile machinery.

The stamped ferrule needle roller bearing without a cage is suitable for swinging working conditions under heavy loads because it is full of needle rollers, such as the aircraft’s frame, the shaft end of the main wing of the missile, etc.

Needle roller bearings with solid ferrules. Commonly used reliable ferrule needle roller bearings are NA type and RNA type.

Scope of application: It is mainly used in machine tools and automobile gearboxes. Its advantages are small radial section size and large radial load.

The standard solid ferrule needle roller bearings have cages, so the speed is high, meeting the requirements of machine tools and gearboxes.