Cylindrical roller bearing category

Cylindrical roller bearing category

Cylindrical roller bearings are separable bearings, which are very convenient for installation and disassembly. Cylindrical roller bearings can withstand larger radial loads and are suitable for use in high-speed running 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'～4'. Therefore, the machining accuracy of the shaft and the bearing seat is relatively high. Otherwise, uneven load or stress concentration will easily occur in the contact part of the raceway. But after correcting the roller or raceway contact bus bar, the occurrence of stress concentration can be reduced.

Cylindrical roller bearings can be divided into single row, double row and multiple row cylindrical roller bearings according to the number of rows of rolling elements. Bearings of different structures are also shown in the design of the rib position. The commonly used cylindrical roller bearings have the following forms:

Single-row cylindrical roller bearings: Single-row cylindrical roller bearings are separable bearings, which are easy to install and disassemble. Both rings can be tightly fitted, and the contact line between the roller and raceway can be modified to reduce stress concentration.

Double-row cylindrical roller bearings: Double-row cylindrical roller bearings are floating bearings, and their separability makes installation and disassembly easy. Both ferrules can be tightly fitted. The double row cylindrical roller bearing almost does not allow inclination angle.

Types of cylindrical roller bearings

N, NU type

N-type bearings have no ribs on the outer ring, and ribs on both sides of the inner ring. It can allow the displacement of the shaft relative to the bearing seat in both axial directions. The NU type bearing has ribs on both sides of the outer ring and no ribs on the inner ring. It can also allow displacement of the shaft relative to the bearing seat in both axial directions. Therefore, this type of structure is suitable for use as a floating 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. It can bear 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, one side of the inner ring has a (fixed) single rib, and the other side is a detachable flat ring. Can bear a certain amount of bidirectional axial load.

NFP type bearing has a (fixed) single rib on one side of the outer ring, and a separable flat ring on the other side, with ribs on both sides of the inner ring. It can also bear a certain amount of bidirectional axial load. This kind 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 of NJ type bearing and HJ type oblique retaining ring. Because the inner ring of the NUP type bearing is short, and the flat retaining ring is not fixed, it is inconvenient to use, while the NH type bearing can use the width of the entire inner ring of the NJ type bearing to maintain a tighter fit with the shaft. And NH type bearing is more convenient to install and disassemble.

The NH type 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.

Double row bearings

Double row cylindrical roller bearings

Double row cylindrical roller bearings

Double-row cylindrical roller bearings have two structures: cylindrical inner bore and conical inner bore (the bearing rear code plus K). This type of bearing has the advantages of compact structure, high rigidity, large carrying capacity, and small deformation after load. It is especially suitable for machine tool spindle support. The conical inner hole can also play the role of micro-adjustment of the 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 forms:

NN, NNU type

The outer ring of the NN type bearing has no ribs, while the inner ring has ribs on both sides and the middle ribs. It can allow the shaft relative to the bearing seat to produce axial displacement in two directions.

NNU type bearings have ribs on both sides of the outer ring, with middle ribs in the middle, and no ribs on the inner ring. It can allow the shaft relative to the bearing seat to produce axial displacement in two directions. Therefore, this type of structure is suitable as a floating end bearing. The cage of this type of bearing mostly adopts a car-made solid cage.

NNF type

NNF type bearings are double-row full complement cylindrical roller bearings. The bearing consists of an outer ring with a central rib and two inner rings with a double rib. The roller is guided by the rib 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 and axial loads, this structure can also withstand overturning moments. Therefore, it is often used as a fixed end bearing.

NNF type bearing adopts contact seal on both sides. The bearing is filled with grease. The working temperature of the grease is -50°C to +110°C, but due to the limitation of the sealing material, the bearing's working temperature is limited to -40°C to +80°C. In the case of good working conditions, the sealed NNF bearing does not need to be maintained. If the bearing is exposed to water vapor or polluted environment for a long time and is running at medium or high speed, it can be adjusted through the lubricating oil groove and lubricating hole on the outer ring.

FC type

The FC type bearing is composed of two outer rings and an inner ring. There are ribs on both sides of each outer ring and a middle rib in the middle, and the inner ring has no ribs.

FCD type

FCD type bearing is actually a combination of two NN type bearings.

FC type and FCD type bearings can allow the shaft relative to the bearing seat to produce axial displacement in two directions. Therefore, this type of structure is suitable as a floating end bearing. The cage of this type of bearing mostly adopts a car-made entity 13:58.