The rolling element is radial rolling bearing of cylindrical roller.

Cylindrical Roller Bearings

The internal structure of the cylindrical roller bearing is arranged in parallel by rollers, and spacers or spacers are arranged between the rollers to prevent the rollers from tilting or friction between the rollers, thereby effectively preventing an increase in the rotational torque.

Overview

Cylindrical rollers and raceways are line contact bearings.

With big load capacity and mainly bear radial load.

The rolling element has little friction with the ferrule rib and is suitable for high speed rotation.

According to the ferrule with or without ribs, it can be divided into single row cylindrical roller bearings such as NU, NJ, NUP, N, NF, and double row cylindrical roller bearings such as NNU and NN.

The bearing is a structure in which the inner ring and the outer ring are separable.

Cylindrical roller bearings with no ribs on the inner or outer ring, the inner and outer rings can move relative to the axial direction, so they can be used as free end bearings.

A cylindrical roller bearing with a single rib on one side of the inner and outer rings and a single rib on the other side can withstand a certain degree of axial load in one direction.

Steel stamping cages or copper alloy solid cages are generally used.

However, some use polyamide shaped cages.

Bearing characteristics

  1. The roller and the raceway are in contact with the wire or repaired, and have a large radial load capacity, which is suitable for bearing heavy loads and impact loads.
  2. The friction coefficient is small, suitable for high speed, and the limit speed is close to the deep groove ball bearing.
  3. N-type and NU-type can move axially, can adapt to the change of the relative position of the shaft and the shell caused by thermal expansion or installation error, and can be used as free end support.
  4. The machining requirements of the shaft or the seat hole are high. After the bearing is installed, the relative deflection of the outer ring axis should be strictly controlled to avoid contact stress concentration.
  5. The inner or outer ring can be separated for easy installation and removal.

Features

The cylindrical roller is in line contact with the raceway and has a large radial load capacity.

Suitable for both heavy and shock loads, as well as for high speed rotation.

Cylindrical roller bearing raceways and rolling elements are geometric.

After the improved design, it has a high carrying capacity.

The new structural design of the rib and the roller end face not only improves the axial bearing capacity of the bearing, but also improves the lubrication condition of the contact area between the roller end face and the rib, and improves the performance of the bearing.

Structural type

 

  1. N0000 type – The outer ring has no rib; NU0000 type – the inner ring has no rib.

 

Cylindrical Roller Bearings – This type of bearing can accept large radial loads, has a high limit speed, does not restrain the axial displacement of the shaft or the casing, and cannot accept axial loads.

 

  1. Cylindrical roller bearings with ribs on the inner and outer rings (NJ0000 and NF0000 bearings) can axially displace the shaft or housing in one direction and accept small one-way axial loads.

 

NU0000+HJ0000, NJ0000+HJ0000, NUP0000 bearings can axially displace shafts or housings in the axial clearance of imported bearings and accept small bidirectional axial loads.

Bearing classification

Cylindrical roller bearings are separate bearings that are easy to install and disassemble.

Cylindrical roller bearings can withstand large radial loads and are suitable for use in high speed applications.

Such bearings allow the angular error (inclination) of the inner ring axis and the outer ring axis to be small, only 2′ to 4′.

Therefore, the machining accuracy of the shaft and the bearing housing is relatively high, otherwise uneven load or stress concentration may occur at the contact portion of the raceway.

However, the correction of the roller or raceway contact busbar can reduce the occurrence of stress concentration.

Cylindrical roller bearings can be divided into different structures such as single row, double row and multi row cylindrical roller bearings depending on the number of rows of rolling elements.

Different structural bearings are also shown in the design of the ribs.

Among them, cylindrical roller bearings are commonly used in the following forms:

Single row cylindrical roller bearing

Single row cylindrical roller bearings are separable bearings for easy installation and disassembly.

A tight fit can be used for both ferrules, and the contact line between the modified roller and the raceway reduces stress concentration.

Double row cylindrical roller bearing

Double row cylindrical roller bearings are floating bearings, and their separability makes installation and disassembly convenient.

A tight fit can be used for both ferrules.

Double row cylindrical roller bearings have almost no inclination angle.

Single row bearing

N, NU type

The outer ring of the N-type bearing has no ribs, and the inner ring has ribs on both sides.

It is possible to allow displacement of the shaft in the axial direction relative to the bearing housing.

The NU type bearing has a rib on both sides of the outer ring, and the inner ring has no ribs.

It is also possible to allow displacement of the shaft relative to the bearing housing in both axial directions.

Therefore, this type of structure is suitable for use as a swim end bearing.

NJ, NF type

NJ-type bearings have ribs on both sides of the outer ring, and the inner ring has ribs on one side.

Can withstand a certain amount of one-way axial load.

The outer ring of the NF type has rib on one side and rib on both sides of the inner ring.

It can also withstand a certain amount of one-way axial load.

Therefore, this type of structure is suitable for use as a unidirectional axially oriented bearing.

NUP, NFP type

The NUP type bearing has rib on both sides of the outer ring, (fixed) single rib on one side of the inner ring, and detachable flat ring on the other side.

Can withstand a certain amount of bidirectional axial load.

The NFP type bearing has (fixed) single rib on one side and detachable flat ring on the other side, and ribs on both sides of the inner ring.

It can also withstand a certain amount of bidirectional axial load.

Such structural bearings can limit the displacement of the shaft in both axial directions relative to the bearing housing.

Therefore, it is suitable for use as a fixed end bearing.

NH(NJ+HJ) type

The NH type bearing is a combination of the NJ type bearing and the HJ type slanting ring.

Because the inner ring of the NUP bearing is short, and the flat ring is not fixed, it is inconvenient to use.

The NH-type bearing can utilize the width of the entire inner ring of the NJ-type bearing to maintain a tighter fit with the shaft.

Moreover, the NH type bearing is more convenient to install and disassemble.

The NH type bearing can limit the displacement of the shaft in both directions with respect to the bearing housing.

Therefore, it is suitable for use as fixed end bearing.

Double row bearing

Double row cylindrical roller bearings have cylindrical inner bore and conical inner bore (bearing rear code plus K).

This kind of bearing has the advantages of compact structure, large rigidity, large bearing capacity, small deformation after load, etc., and is especially suitable for machine tool spindle support.

The conical inner hole can also play a role of slightly adjusting the clearance, and can simplify the structure of the positioning device, and is convenient for installation and disassembly.

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

NN, NNU type

The outer ring of the NN bearing has no ribs, and the inner ring has middle rib in the middle of the rib.

It is possible to allow displacement of the shaft in the axial direction relative to the bearing housing in both directions.

NNU type bearings have middle rib on the outer side of the outer ring and no rib on the inner side.

It is possible to allow displacement of the shaft in the axial direction relative to the bearing housing in both directions.

Therefore, such a structure is suitable as a swim end bearing.

Most of the cages of this type of bearing use a vehicle-made solid cage.

NNF type

The NNF type bearing is double row full complement cylindrical roller bearing.

The bearing consists of a structure with middle rib outer ring and two double rib inner rings.

The rollers are guided by the ribs of the inner ring and the two inner rings are fastened together by fastening rings.

In addition to being able to withstand large radial loads and axial loads, the structure can withstand overturning moments.

Therefore, it is often used as a fixed end bearing.

Contact seals are used on both sides of the NNF type bearing.

The bearing is filled with grease, the working temperature of the grease is -50 °C ~ +110 °C.

However, due to the limitation of the sealing material, the operating temperature of the bearing is limited to between -40 °C and +80 °C.

In the case of better working conditions, the sealed NNF bearing does not require maintenance.

If the bearing is in water vapor or polluted environment for a long time, and it is running at medium and high speed, the bearing can be relubricated through the lubricating oil groove and the lubricating oil hole on the outer ring.

Four row bearing

Four row cylindrical roller bearings are mainly used in rolling mill machinery such as cold and hot rolling mills and blanking machines.

The bearing is a separate structure.

The bearing ring and rolling element assembly can be easily separated.

Therefore, it is convenient to clean, inspect or install and disassemble the bearing.

FC type

The FC type bearing is composed of two outer rings and one inner ring, and each of the outer rings has middle rib in the middle of the rib and rib in the inner ring.

FCD type

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

FC and FCD bearings allow for axial displacement in the axial direction relative to the housing.

Therefore, such a structure is suitable as a swim end bearing.

The cage of this type of bearing mostly uses the milling body 13:58.

Bearing applications

  • Large and medium motor
  • Locomotive vehicle
  • Machine tool spindle
  • Internal combustion engine
  • Generator
  • Gas turbine
  • Gearbox
  • Rolling mill
  • Vibrating screen
  • Lifting and transport machinery