Full-filling Thrust Tapered Roller Bearings

Product Description

Tapered roller thrust bearings include rollers that have conical sections. These bearings have been engineered so that the rollers and raceways form a cone in which the vertex is on the center line of the bearing. This bearing geometry assures a true rolling motion. In addition, the large end of each tapered roller is spherically ground so that its curvature conforms with the concave face of the washer rib. Pressure between the rib and roller, under load, guides the rollers accurately.

NEWORLD tapered roller thrust bearings are designed to accommodate heavy axial loads and peak loads. The bearings are very stiff and require little axial space.

NEWORLD tapered roller thrust bearings are produced with the logarithmic contact profile between raceways and rollers to guarantee optimum stress distribution in the bearing, thus enhancing bearing life.

NEWORLD tapered roller thrust bearings with cage are of separable design so that the two washers and the roller and cage thrust assembly can be mounted separately and easily. The full complement screw-down bearings are held together by special retaining components and, to simplify handling, the washers have threaded holes for eye bolts.

Designs and variants

NEWORLD manufactures, as standard, tapered roller thrust bearings in the following basic and application-specific designs:

●  single direction tapered roller thrust bearings (fig. 1)

●  double direction tapered roller thrust bearings (fig. 2)

●  screw-down bearings (fig. 3)

Single direction tapered roller thrust bearings

Single direction tapered roller thrust bearings

●  are available as symmetrical or asymmetrical variants with regard to the shaft and housing washers

    ◌  symmetrical variants (fig. 4):

         ▪  have shaft and housing washers in the same design with tapered raceways and one guide flange

         ▪  are preferred where very heavy axial loads are to be supported, for example in the swivels or top 

            drives of drilling rigs or in crane hooks

    ◌  asymmetrical variants (fig. 5):

         ▪  have a shaft washer with tapered raceway and guide flange, whilst the housing washer has a flat 

            (plane) raceway

         ▪  carry higher axial loads than same-sized symmetrical variants, because longer rollers can be 

            incorporated

         ▪  can compensate minor eccentricity of the shaft relative to the housing bore

         ▪  are fitted with a roller centred cage

●  are available in several variants, for example with a different housing washer and cover (fig. 6)

Small single direction tapered roller thrust bearings

●  are used almost exclusively for the kingpin bearing arrangement of commercial vehicles (fig. 7)

●  are available with a full complement of rollers and are held together by a sheet steel cover (fig. 8)

●  are available with wear- and oil-resistant NBR seals (fig. 9) and lubricated for life with a multi-purpose 

    grease

Large single direction tapered roller thrust bearings

●  are used mainly for top drive systems in the oil and gas industry

●  are designed to boost top drive reliability with long service life and high load carrying capacity

Double direction tapered roller thrust bearings

Double direction tapered roller thrust bearings

●  are mainly used together with double row cylindrical roller bearings or four-row cylindrical roller 

    bearings in rolling mill applications 

●  are available with a flat (plane) shaft washer or with tapered raceways on both the shaft and housing 

    washers 

    ◌  variants with a flat shaft washer (fig. 11):

        ▪  can compensate minor eccentricity of the shaft relative to the housing bore - for example, 

           to the extent of the internal clearance of the radial bearing (fig. 10)

        ▪  have a spacer sleeve between the two housing washers, which is designed so that the cover 

           screws of the chock can be fully tightened and no springs are required

    ◌  variants with tapered raceways on both washers (fig. 12):

        ▪  generally have a higher axial load carrying capacity compared with bearings with a flat shaft washer

        ▪  can radially locate the shaft, to a certain extent

●  are available with a shaft washer that has one or two locating slots to prevent the shaft washer from 

    rotating on its seat, because the bearings are usually mounted with a loose fit on the roll neck as well as 

    in the chock

If the load carrying capacity of double direction tapered roller thrust bearings is insufficient, a double row tapered roller bearing with a steep contact angle, for example in the TDIS design, could be an alternative.

Screw down bearing

Screw-down bearings

●  are used almost exclusively in rolling mill screw-down applications

●  are a special design (fig. 13) of single direction tapered roller thrust bearings

●  are tailored to customer requirements

●  have a full complement of rollers with extremely long rollers of large diameter

●  can accommodate extremely heavy axial loads

●  are held together by special retaining components

●  have washers with threaded holes for eye bolts to simplify handling

●  can compensate angular movement of the screw spindle relative to its support

●  can accommodate alignment movements of the chock without detrimental effect on bearing 

    performance by using either a spherical shaft washer (fig. 14) or a spherical housing washer (fig. 15)

    ◌  spherical shaft washer:

        ▪  alignment movements are accommodated above the roller complement between the spherical 

           shaft washer and a corresponding concave screw spindle or pressure plate (fig. 16)

    ◌  spherical housing washer:

        ▪  alignment movements are accommodated below the roller complement between the housing 

           washer and a pressure plate

    ◌  NEWORLD also supplies the suitable pressure plates

Application

Cages

NEWORLD tapered roller thrust bearings that do not have a full complement of rollers are fitted with one (for single direction bearings) or two (for double direction bearings) of the following cages:

●  machined brass cage (fig. 17)

●  steel pin-type cage (pierced rollers, fig. 18)

●  pressed steel window-type cage (fig. 19)

Temperature limits

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

●  the dimensional stability of the bearing washers, spacer sleeves and rollers

●  the cage

●  the seal

●  the retaining component

●  the lubricant

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

Bearing washers, spacer sleeves and rollers

NEWORLD tapered roller thrust bearings are heat stabilized up to at least 120 °C (250 °F).

Cages

Steel or brass cages can be used at the same operating temperatures as the bearing washers, sleeves and rollers.

Seals

The permissible operating temperature for NBR seals is –40 to +100 °C (–40 to +210 °F). Temperatures up to 120 °C (250 °F) can be tolerated for brief periods.

Typically, temperature peaks are at the seal lip.

Retaining components

Sheet steel covers can be used at the same operating temperatures as the bearing washers, sleeves and rollers.

The permissible operating temperature for O-rings is –40 to +100 °C (–40 to +210 °F). Temperatures up to 120 °C (250 °F) can be tolerated for 

Features and benefits

●  Separable design

    The shaft and housing washers and the roller and cage thrust assemblies of tapered roller thrust 

    bearings with cages can be mounted separately.

●  Low friction

    The optimized roller end design and surface finish on the flange promote lubricant film formation, 

    resulting in lower friction. This also reduces frictional heat and flange wear.

●  Long service life

    Depending on the design, crowned or logarithmic raceway profiles optimize the load distribution along 

    the contact surfaces, reduce stress peaks at the roller ends, and reduce the sensitivity to misalignment 

    compared with conventional straight raceway profiles (fig. 1).

●  Enhanced operational reliability

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

    hydrodynamic lubricant film.

●  High load carrying capacity

    The rollers incorporated in SKF tapered roller thrust bearings are manufactured to such close 

    dimensional and geometrical tolerances that they are practically identical. This provides optimal 

    load distribution and enables the bearings to accommodate heavy axial loads

Applications

Here are examples of applications in which tapered roller thrust bearings might be used:

● Material handling

● Industrial transmissions

● Machine tools

● Trucks, trailers and buses

● Aggregate

● Metals

● Oil, Power Generation

● Cone crushers

● Crane hooks

● Oil well swivels

● Extruders 

● Pulverizer drives

● Rolling machine tool spindles & tables 

● Drilling rig hydraulic heads

● Gear boxes, 

● Pre-heater fans  

● Mill roll necks