Introduction to cylindrical roller bearings

Most cylindrical roller bearings are separate bearings, which are very convenient to install and disassemble. Cylindrical rollers can withstand large radial loads and are suitable for use in high-speed operation situations. This type of bearing allows the angular error (inclination) between the axis of the inner ring and the axis of the outer ring to be very small, only 2 to 4'. Therefore, the machining accuracy requirements for the shaft and bearing seat are relatively high. Otherwise, uneven loads or stress concentration will easily occur at the raceway contact parts. However, the occurrence of stress concentration can be reduced by correcting the roller or raceway contact busbar.

Cylindrical roller bearings can be divided into different structures such as single-row, double-row and multi-row cylindrical roller bearings according to the number of rows of rollers. Different structural bearings are also reflected in the position design of the ribs. Among them, the commonly used LYC cylindrical roller bearings have the following shapes:

Single row cylindrical roller bearings

N, NU type

The outer ring of N-type bearings has no ribs, and the inner ring has ribs on both sides. It allows for axial displacement in both directions between the shaft and the bearing seat.

The NU type bearing has ribs on both sides of the outer ring and no ribs on the inner ring. It is also possible to allow axial displacement in both directions between the shaft and the bearing seat. Therefore, this type of structure is suitable for use as a free end bearing.

NJ, NF type

NJ type bearings have ribs on both sides of the outer ring and ribs on one side of the inner ring. Can withstand a certain amount of unidirectional axial load

The NF type has ribs on one side of the outer ring and ribs on both sides of the inner ring. It can also bear a certain amount of unidirectional axial load.

Therefore, this type of structure is suitable for use as a unidirectional axial positioning bearing.

NUP, NFP type

NUP type bearings have ribs on both sides of the outer ring, a (fixed) single rib on one side of the inner ring, and a detachable flat ring on the other side. Can withstand a certain amount of bidirectional axial load.

The NFP type bearing has a (fixed) single rib on one side of the outer ring, a detachable flat rib on the other side, and ribs on both sides of the inner ring. It can also bear a certain amount of bidirectional axial load.

This type of structural bearing can limit the displacement of the shaft relative to the bearing seat in both axial directions. Therefore, it is suitable for use as a fixed-end bearing.

NH(NJ+HJ) type

NH type bearing is a combination structure of NJ type bearing and HJ type ramp. Since the inner ring of the NUP type bearing is shorter and the flat retaining ring is not fixed, it is inconvenient to use. The NH type bearing can use the entire width of the inner ring of the NJ type bearing to maintain a closer fit with the shaft. Moreover, NH type bearings are more convenient to install and disassemble.

NH type bearings can limit the displacement of the shaft relative to the bearing seat in both axial directions. Therefore, it is suitable for use as a fixed-end bearing.

Double row cylindrical roller bearings

double row cylindrical roller bearings have two structures: cylindrical inner bore and conical inner bore (bearing suffix code plus K). This type of bearing has the advantages of compact structure, high rigidity, large load-bearing capacity, and small deformation after being loaded. It is especially suitable for machine tool spindle support. The conical inner hole can also play a role in micro-adjustment of clearance, and can simplify the structure of the positioning device and facilitate installation and disassembly.

Commonly used double row cylindrical roller bearings have the following formulas:

NN, NNU type

The outer ring of the NN type bearing has no ribs, and the inner ring has ribs on both sides and a middle rib in the middle. It allows axial displacement in two directions between the shaft and the bearing seat.

The NNU type bearing has ribs on both sides of the outer ring and a middle rib in the middle, and the inner ring has no ribs. It can allow axial displacement in two directions between the shaft and the bearing seat.

Therefore, this type of structure is suitable for free end bearings

NNF type

NNF type bearing is a double row full complement cylindrical roller bearing. The bearing consists of an outer ring with a middle rib and two inner rings with a double rib. The rollers are guided by the ribs of the inner ring, and the two inner rings are fixed together with a fastening ring. In addition to being able to withstand large radial loads and axial loads, this structure can also withstand overturning moments. Therefore, it is often used as a fixed-end bearing.

NNF type bearings adopt contact seals on both sides. The bearing is filled with grease, and the operating temperature of the grease is 50°C to +110°C. However, due to the limitations of the sealing material, the operating temperature of the bearing is limited to -40°C to +80°C. Under better circumstances, sealed NF bearings do not require maintenance, but the bearings can be exposed to moisture or pollution for a long time. When running at medium or high speeds, the bearings can be relubricated through the lubricating oil grooves and lubricating oil holes on the outer ring.

Four row cylindrical roller bearings

four-row cylindrical roller bearings are mainly used in rolling mill machinery such as hot and cold rolling mills and blanking machines. The bearings have a separate structure. The bearing rings and rolling element components can be easily separated. Therefore, the cleaning, inspection or It is very convenient to install and disassemble.

FC type

FC type bearings are composed of two outer rings and one inner ring. Each outer ring has ribs on both sides and a middle rib in the middle. The inner ring has no ribs.

FCD type

FCD type bearings are actually composed of two NN type bearings.

FC type and FCD type bearings can allow axial displacement in two directions between the shaft and the bearing seat. Therefore, this type of structure is suitable for free end bearings. The cages of this type of bearings mostly use machined solid cages.

special design

E-type structural design

Compared with the earlier designed cylindrical roller bearings of the same type, the internal design of the bearing has been improved, and the bearing load-bearing capacity and service life have been increased. In order to distinguish it from the bearings of earlier designs, it is represented by the postcode E.

Tapered bore bearings

The inner bore of single-row and double-row cylindrical roller bearings is generally a cylindrical bore, but some sizes and specifications can also provide tapered bore bearings with a taper of 1:12, which add K to the bearing suffix code.

Bearings with stop groove

can also provide single-row cylindrical roller bearings with stop grooves in the outer ring. The bearings can be positioned with stop rings. During installation, the bearings can be easily fixed in the bearing seat. Therefore, when the axial installation position is limited, priority can be given to selection. It adds N to the bearing suffix code.

can also provide customers with other structural forms of cylindrical roller bearings, such as insulated cylindrical roller bearings, cylindrical roller bearings without inner or outer rings, full complement cylindrical rollers, sealed cylindrical roller bearings, etc. Products, but due to the large number of structures, they cannot be listed in this sample. If customers need it, they can consult the LYC technical department.

can also design and manufacture other cylindrical roller bearing types for customers that meet their individual requirements.

cage

single row cylindrical roller bearing cages are mostly steel plate stamped cages or brass machined solid cage structures. We can also design and provide bearings with glass fiber reinforced nylon 66 cages according to the use occasion and customer requirements. Bearings with glass fiber reinforced nylon 66 cages can continue to rotate at temperatures up to +120°C.

For single-row cylindrical roller bearing cages operating under sustained high temperatures or harsh conditions, it is recommended to use steel plate stamped cages and brass machined solid cage structures.

double (four) row cylindrical roller bearing cages generally adopt a brass machined solid cage structure. For extra large bearings, there are also welded pillar steel cage structures.