Roller Bearing
In bearings of this type, the cylindrical rollers are in linear contact with the raceways. They have a high radial load capacity and are suitable for high speeds.
There are different types designated as NU, NJ, NUP, N, NF (for single-row bearings), NNU, and NN (for double-row bearings depending on the design or absence of side ribs).
The outer and inner rings of all types are separable.
Some cylindrical roller bearings have no ribs on either the inner or outer ring, so the rings can move axially relative to each other. These can be used as free-end bearings. Cylindrical roller bearings, in which either the inner or outer rings has two ribs and the other ring has one, are capable of taking some axial load in one direction Double-row cylindrical roller bearings have high radial rigidity and are used primarily for precision machine tools.
Pressed steel or machined brass cages are generally used, but sometimes molded polyamide cages are also used.
Depending on the existence of ribs on their rings, Cylindrical Roller Bearings are classified into the following types:
Types NU, N, NNU, and NN are suitable as free-end bearings. Types NJ and NF can sustain limited axial loads in one direction. Types NH and NUP can be used as fixed-end bearings.
NH-type cylindrical roller bearings consist of the NJ-type cylindrical roller bearings and HJ-type L-shaped thrust collars.
The inner ring loose rib of an NUP-type cylindrical roller bearing should be mounted so that the marked side is on the outside.
Bearings of this type use conical rollers guided by a back-face rib on the cone. These bearings are capable of taking high radial loads and axial loads in one direction.
In the HR series, the rollers are increased in both size and number giving it an even higher load capacity. They are generally mounted in pairs in a manner similar to single-row angular contact ball bearings. In this case, the proper internal clearance can be obtained by adjusting the axial distance between the cones or cups of the two opposed bearings. Since they are separable, the cone assemblies and cups can be mounted independently.
Depending upon the contact angle, tapered roller bearings are divided into three types; normal angle, medium angle, and steep angle.
Double-row and four-row tapered roller bearings are also available. Pressed steel cages are generally used.
Metric Design Tapered Roller BearingsFor metric-design medium-angle and steep-angle tapered roller bearings, the respective contact angle symbol C or D is added after the bore number. For normal-angle tapered roller bearings, no contact angle symbol is used. Medium-angle tapered roller bearings are primarily used for the pinion shafts of differential gears of automobiles. Among those with high load capacity (HR series), some bearings have the basic number suffixed by J to conform to the specifications of ISO for the cup back face raceway diameter, cup width, and contact angle. Therefore, the cone assembly and cup of bearings with the same basic number suffixed by J are internationally interchangeable. Among metric-design tapered roller bearings specified by ISO 355, there are those having new dimensions that are different than the dimension series 3XX used in the past. Part of them are listed in the bearing tables. They conform to the specifications of ISO for the smaller end diameter of the cup and contact angle. The cone and cup assemblies are internationally interchangeable. The bearing number formulation, which is different than that for past metric design, is as follows:
Inch Design Tapered Roller Bearings
Besides metric design tapered roller bearings, there are also inch design bearings. For the cone assemblies and cups of inch design bearings, except four-row tapered roller bearings, the bearing numbers are approximately formulated as follows:
Design and Feadtured of Combinations of Tapered Roller Bearings
Product List
Shown in the figures, types EA, C, CD, CA, which are designed for high load capacity, are available. Types EA, C, and CD have pressed steel cages; and type CA has machined brass cages. Type EA has especially high load capacity, features low torque, and has a high-strength cage.
An oil groove and holes are provided in the outer ring to supply lubricant and the bearing numbers are suffixed with E4.
To use bearings with oil grooves and holes, it is recommended to provide an oil groove in the housing bore, since the depth of the groove in the bearing is limited.
Product List
Available with cylindrical or spherical rollers, NSK’s thrust roller bearings sustain only axial loads, but they are suitable for heavy loads and have high axial rigidity. Spherical thrust roller bearings contain convex rollers and have a self- aligning capability and are free of any influence of mounting error or shaft deflection. Standard cages are machined brass, where the E-type offers a pressed cage for high load capacity.
These are thrust bearings containing cylindrical rollers. They can sustain only axial loads, but they are suitable for heavy loads and have high axial rigidity.
The cages are machined brass.
These are thrust bearings containing convex rollers. They have a self-aligning capability and are free of any influence of mounting error or shaft deflection. Besides the original type, the E type with pressed cages for high load capacity is also available. Their bearing numbers are suffixed by E.
For horizontal shaft or high speed application, machined brass cages are recommended. For details, contact NSK. Since there are several places where lubrication is difficult, such as the area between the roller heads and inner ring rib, the sliding surfaces between cage and guide sleeve, etc., oil lubrication should be used even at low speed. The cages in the original type are machined brass.
Product List
Axial loads in one direction can be sustained.
Axial loads in both directions can be sustained by shaft sleeve.
Needle roller bearings are a bearing that is classified as either radial or thrust depending on the direction of the load being supported. Needle roller bearings include bearings whose rollers slightly exceed the size range of needle rollers as stipulated by ISO. Needle roller bearings include drawn cup and solid radial bearings, as well as application-specific cam followers, and roller followers. Thrust bearings include thrust needle bearings.
Product List
NSK cage & Needle roller assemblies consist of a complement of needle rollers held in place by a cage. Their unitized design makes for easy handling and installation. With no inner or outer ring, the low cross-section provides maximum load-carrying capability within the smallest envelope.
Properly lubricated, they can operate at high speeds thanks to the unique cage, which guides the rollers precisely. The controlled contour rollers in cage & Needle roller assemblies have an optimum profile which reduces end stresses, allows operation under moderate misalignment and prolongs bearing life.
Solid needle roller bearings are high-accuracy bearings with maximum load capacity within a limited space for various operating conditions. Made of carefully selected vacuum-degassed bearing steel or carburizing steel, the raceway rings are finished with accurate grinding after heat treatment. The outer rings have strong integrated ribs and contain high-accuracy rollers that have the proper crowning finish. Lightweight and extremely strong, the cage guides the rollers accurately and smoothly.
Thrust needle bearings type comes in metric and inch designs. The cage & Needle roller assembly for the thrust needle bearing is a cage that has two pieces joined together, to which surface hardening is applied after the precision press processing of a steel plate, and in which high accuracy rollers are incorporated, in order to achieve rigidity and wear resistance. Many rollers are retained securely in the cage, taking large axial load, and yet rotating smoothly. Mounting space is so small that it is easy to replace a conventional sliding thrust washer. Different thicknesses of various types of thrust raceway washers are available in this cage & Needle roller assembly, which allows selection of the appropriate thickness suited for bearing peripheral mounting conditions.
Cam followers, which are equipped with a thick-wall outer ring, crowned rollers, and a stud with a hardened raceway surface, are especially tough and can sustain shock loads.
The roller follower with a thick-wall outer ring and crowned roller has a large load capacity which enables it to carry shock loads. Handling is easy since it it non-separating and applications such as track rollers, cams and rocker arms are wide.
