WD Tapered Roller Bearings | Taper Roller Bearing

Home > Leading Products > Precision Tapered Roller Bearings

Precision Tapered Roller Bearings

WD tapered roller bearings are produced by WD in many designs and sizes to match their many uses.These can be grouped as follows

Design features：
WD tapered roller bearings have tapered inner and outer ring raceways between which tapered rollers are arranged. The projection lines of all the tapered surfaces meet at a common point on the bearing axis. Their design makes tapered roller bearings particularly suitable for the accommodation of combined (radial and axial) loads. The axial load carrying capacity of the bearings is largely determined by the contact angle ; the larger contact angle the greater axial load carrying capacity . An indication of the angle size is given by the calculation factor ; the larger the value of , the larger the contact angle and the greater suitability of the bearing for carrying axial loads.

Tapered roller bearings are generally separable, i.e. the cone, consisting of the inner ring with roller and cage assembly, can be mounted separately from the cup (outer ring).

WD tapered roller bearings have the logarithmic contact profile that provides optimum stress distribution over the roller/raceway contacts. The special design of the sliding surfaces of the guide flange and large roller ends considerably promote lubricant film formation in the roller end/flange contacts. The resulting benefits include increased operational reliability and reduced sensitivity to misalignment.

Metric bearings

The boundary dimensions of metric single row tapered roller bearings listed in the product tables conform to ISO 355-1977 .

The inner rings with roller and cage assembly and outer rings of WD tapered roller bearings having the same designation are interchangeable. The tolerance for the total abutment width T of the bearing will not be exceeded if the cones and cups are interchanged.

WD single-row metric tapered roller bearings are manufactured to Normal tolerances as standard. Some bearings are also available with reduced width tolerance to tolerance class CLN specifications. Bearings having a J in the prefix are produced as standard to tolerance class CLN specifications.

All bearings having an outside diameter above 420 mm have dimensional accuracy to tolerance class Normal specifications but the running accuracy is better than Normal, being P6 specifications.

The values for Normal and CLN tolerances correspond to ISO 492:2002 (classes Normal and 6X). The values for P6 running accuracy are in accordance with DIN 620-3:1964, which was withdrawn in 1988.

Internal clearance and preload

The internal clearance of single row tapered roller bearings can only be obtained after mounting and is determined by adjustment of the bearing against a second bearing, which provides location in the opposite direction. Further details can be found in the section "Bearing preload".

Adjustment and running-in

When adjusting tapered roller bearings against each other, the bearings must be rotated, so that the rollers assume their correct position, i.e. the large end face of the rollers must be in contact with the guide flange.

Conventional tapered roller bearings normally have a relatively high friction torque during the first hours of operation, which drops to a lower level after the running-in period. During this running-in period, bearing temperature increases rapidly because of the high initial friction and falls off to an equilibrium level as the running-in phase is completed.

This running-in phase is considerably reduced with bearings made to the specification. In these bearings, the initial friction is also much lower, so that temperature increase is almost negligible. This also applies to the high-performance CL7C specification bearings, which are designed for easy adjustment.

Misalignment

The ability of a conventional single row tapered roller bearing to accommodate angular misalignment of the inner ring with respect to the outer ring is limited to a few minutes of arc. Bearings have the logarithmic contact profile and can tolerate misalignments of approximately 2 to 4 minutes of arc.

These guideline values apply provided the position of the shaft and housing axes are constant. Larger misalignment is possible, depending on the load and requisite service life. For additional information, please contact the application engineering service.

Cages
WD tapered roller bearings are fitted with one of the following cages.
-A pressed window-type steel cage, roller centred.
-An injection moulded window-type cage of glass fibre reinforced polyamide 6,6, roller centred.