Cylindrical roller bearings are radial rolling bearings in which the rolling elements are cylindrical rollers. The bearing has a separable structure with an inner ring and an outer ring. The rollers in the bearing are arranged in parallel. The interval retainer or spacer is installed between each cylindrical roller, which can prevent the tilting of rollers or friction between the rollers, and also effectively prevent the increase of rotational torque. Cylindrical rollers and raceways are line contact structure, so the bearing primarily bears a large radial load. The friction between the rolling element and ring ribs is small, which is good for high-speed rotation. Depending on whether the ring has ribs or not, 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, NN. Cylindrical roller bearings without ribs on their inner or outer rings and the rings can move relatively in the axial direction, so they can be used as free-end bearings. Cylindrical roller bearings with double ribs on one side and a single rib on the other side of their rings, they can withstand a certain degree of axial load in one direction. Stamped steel cages, copper alloy cages or polymer cages are generally used inside the bearing.
Cylindrical roller bearing has the following characteristics:
1. Rollers and raceways are in line contact, with a large radial loading capacity, suitable for bearing heavy load and impact load;
2. The friction coefficient is small, suitable for high speed, and its limiting speed is very close to deep groove ball bearings;
3. N type and NU type can move axially, can adapt to the relative position changes of the shaft and the housing, which is caused by thermal expansion or installation error. Both types can be used as free end supports;
4. High processing requirement for the shaft or holes in the housing. The relative deflection of the outer ring axis after the installation must be strictly controlled to avoid contact stress concentration;
5. The inner or outer ring can be separated for easy installation and removal.
The applications of cylindrical roller bearings are wide, such as in medium or large electric motors, machine tool spindles, internal combustion engines, generators, gas turbines, reduction gearboxes, rolling mills, vibrating screens, and lifting and transportation machinery.