Single row cylindrical roller bearings

Product Description

NEWORLD single row cylindrical roller bearings are available in many designs, series and sizes. The major design differences between the bearings presented in this section are in:

   ●  the cage design and material

   ●  the configuration of the inner and outer ring flanges (fig. 1)

Features and benefits

   ●  Low friction (Roller end / flange contact area)

       The open flange design (fig. 2), together with the roller end design and surface finish, promote 

       lubricant film formation resulting in lower friction and higher axial load carrying capacity.

   ●  Long service life

       The logarithmic roller profile reduces edge stresses at the roller/raceway contact (fig. 3) and 

       sensitivity to misalignment and shaft deflection.

   ●  Enhanced operational reliability

       The surface finish on the contact surfaces of the rollers and raceways supports the formation of a 

       hydrodynamic lubricant film.

   ●  Separable and interchangeable

       The separable components of SKF cylindrical roller bearings are interchangeable (fig. 4). This 

       facilitates mounting and dismounting, as well as maintenance inspections.

   ●  High speed capability

       The cage designs are suitable for high speeds, rapid accelerations and peak loads.

COMMON BEARING DESIGN

Common designs

The most common designs of single row cylindrical roller bearings are shown in fig. 5.

NU design bearings 

   ●  have two integral flanges on the outer ring and no flanges on the inner ring

   ●  can accommodate axial displacement of the shaft relative to the housing in both directions

   ●  can be used together with an appropriate angle ring to stabilize the bearing in the axial direction (fig. 

       6, Appropriate angle rings)

N design bearings 

   ●  have two integral flanges on the inner ring and no flanges on the outer ring

   ●  can accommodate axial displacement of the shaft relative to the housing in both directions

NJ design bearings 

   ●  have two integral flanges on the outer ring and one on the inner ring

   ●  can accommodate axial displacement of the shaft relative to the housing in one direction only

   ●  are used to locate the shaft axially in one direction

   ●  can be used together with an appropriate angle ring to stabilize the bearing in the other axial 

       direction (fig. 7, Appropriate angle rings)

NUP design bearings 

   ●  have two integral flanges on the outer ring and one integral flange and one non-integral flange, i.e. a 

       loose flange ring, on the inner ring

   ●  are used to locate the shaft axially in both directions

Appropriate angle rings (thrust collars)

   ●  are used with NU design bearings to locate the shaft axially in one direction (fig. 6)

       Angle rings should not be used on both sides of NU design bearings as this can lead to axial clamping 

       of the rollers.

   ●  are used with NJ design bearings to locate the shaft axially in both directions (fig. 7)

   ●  are made of carbon chromium steel

   ●  are hardened and ground

   ●  have a maximum axial run-out that is in accordance with the Normal tolerance class for the 

       appropriate bearing

   ●  are identified by the series designation HJ followed by the appropriate bearing dimension series and 

       size

   ●  are available as listed in the data table

   ●  must be ordered separately

Reasons to design angle rings into a bearing arrangement include:

   ●  no NJ or NUP design locating bearings in the product range

   ●  to provide an extended inner ring seat for heavily loaded bearings in the locating position:

       ◌  full width inner ring seat of NJ design bearings with an HJ angle ring compared to NUP design 

           bearings having a shorter inner ring and a loose flange

   ●  to simplify design or mounting procedures

Other bearing design

Other designs (fig. 9）

NUB design bearings 

   ●  have two integral flanges on the outer ring and no flanges on the inner ring that is extended on both 

       sides

   ●  can accommodate axial displacement of the shaft relative to the housing in both directions

NJP design bearings

   ●  have two integral flanges on the outer ring and one non-integral flange, i.e. a loose flange ring, on the 

       inner ring

   ●  are used to locate the shaft axially in one direction

NF design bearings

   ●  have two integral flanges on the inner ring and one integral flange on the outer ring

   ●  are used to locate the shaft axially in one direction

NP design bearings 

   ●  have two integral flanges on the inner ring and one integral flange and one non-integral flange, i.e. a 

       loose flange ring, on the outer ring

   ●  are used to locate the shaft axially in both directions

Other variants

Bearings without an inner or outer ring

    ●  are available based on:

        ◌  NU design bearings without an inner ring (RNU series, fig. 10 )

            ▪  enable the shaft diameter to be larger to provide a stronger, stiffer shaft

            ▪  provide inside diameter Fw tolerance limits in accordance with DIN 5412-1

            ▪  are listed in the data table for certain sizes

        ◌  N design bearings without an outer ring (RN series, fig. 11 )

    ●  can accommodate axial displacement of the shaft relative to the housing, limited by the width of the 

        raceway:

        ◌  on the shaft for RNU bearings

        ◌  in the housing for RN bearings

    ●  are typically used in applications where hardened and ground raceways can be machined on the 

        shaft or in the housing (Raceways on shafts and in housings)

Bearings with a tapered bore (fig. 12)

   ●  are available with a 1:12 tapered bore (designation suffix K)

   ●  have radial internal clearance greater than corresponding bearings with a cylindrical bore

Bearings with a snap ring groove in the outer ring (fig. 13)

   ●  are identified by the designation suffix N

   ●  can be axially located in the housing by a snap ring:

       ◌  to save space

       ◌  to reduce mounting time

Bearings with locating slots in the outer ring (fig. 14)

   ●  are available with one or two locating slots (designation suffix N1 or N2)

       The two locating slots are positioned 180° apart.

   ●  can be used to prevent the outer ring from turning where it must be mounted with a loose fit

Matched bearings

   ●  are combined so that any difference in cross-sectional height of the bearings used in a matched set 

       lies within a very small tolerance range. This tighter tolerance is a precondition for equal load sharing 

       between the bearings.

   ●  can be supplied as:

       ◌  sets of two bearings (designation suffix DR)

       ◌  sets of three bearings (designation suffix TR)

       ◌  sets of four bearings (designation suffix QR)

High-capacity cylindrical roller bearings

High-capacity cylindrical roller bearings 

NEWORLD high-capacity cylindrical roller bearings (fig. 15) are designed for applications such as industrial gearboxes, wind turbine gearboxes and mining equipment.

The cage bars are displaced relative to the roller pitch diameter to enable the rollers to be placed closer to each other, creating room for additional rollers (fig. 16) and thereby increasing load carrying capacity and radial stiffness.

The black oxide coating of rings and rollers (designation sufix L4B) contributes to extended service life by improving: 

   ●  smearing damage resistance 

   ●  running-in properties and reducing friction 

   ●  performance under poor lubrication conditions 

   ●  chemical resistance (from aggressive oil additives) 

   ●  corrosion resistance

NEWORLD high-capacity cylindrical roller bearings are available in three different main designs and some variants

Bearings with an inner ring centred cage 

   ●  are identified by the series designation NCF ECJB (fig. 17) 

   ●  are used to locate the shaft axially in one direction and eventually to accommodate axial 

       displacement of the shaft relative to the housing in the opposite direction 

   ●  can be supplied without an outer ring (RN ECJB series, fig. 17), where the outer raceway is integrated 

       into the application

Bearings with an outer ring centred cage 

   ●  are identiied by the series designation NJF ECJA (fig. 18) 

   ●  for some sizes, contain more rollers than same-sized bearings with an inner ring centred cage 

   ●  are used to locate the shaft axially in one direction and eventually to accommodate axial 

       displacement of the shaft relative to the housing in the opposite direction 

   ●  can be supplied without an inner ring (RNU ECJA series, fig. 18), where the inner raceway is integrated 

       into the application 

Separable bearings with an inner ring raceway centred cage 

   ●  are identified by the series designation NUH ECMH (fig. 19) 

   ●  can accommodate axial displacement of the shaft relative to the housing in both directions 

   ●  can be separated (outer ring with the roller and cage assembly from the inner ring), which simplies 

       mounting and dismounting, particularly where load conditions require both rings to have an 

       interference fit

Application

Cages

NEWORLD single row cylindrical roller bearings are fitted with one of the cages shown in table 1. and  single row and high-capacity cylindrical roller bearings are fitted with one of the cages shown in table 2. 

When used at high temperatures, some lubricants can have a detrimental effect on polyamide cages. 

Temperature limits

The permissible operating temperature for cylindrical roller bearings can be limited by:

●  the dimensional stability of the bearing rings and rollers

●  the cage

●  the lubricant

Where temperatures outside the permissible range are expected, contact NEWORLD.

Bearing rings and rollers

NEWORLD cylindrical roller bearings are heat stabilized up to 150 °C (300 °F).

Cages

Steel, brass, light alloy or PEEK cages can be used at the same operating temperatures as the bearing rings and rollers. For temperature limits of cages made of other polymer materials, refer to Polymer cages.

Application:

   ●  Motors 

   ●  Electricity generators

   ●  Internal combustion engines

   ●  Gas turbines

   ●  Machine tool spindles

   ●  Deceleration devices

   ●  Unloading and lifting machines

   ●  Power generation

   ●  Oil field

   ●  Mining and aggregate

   ●  Processing

   ●  Gear drives

   ●  Rolling mills