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Above 420mm Dimension Standard Precision Tapered Roller Ball Bearings 30220
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Above 420mm Dimension Standard Precision Tapered Roller Ball Bearings 30220

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. Taper roller bearing
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.


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, roler centred.    

-A steel pin-type cage

Minimum load In order to provide satisfactory operation, tapered roller bearings, like all ball and roller bearings, must always be subjected to a given minimum load, particularly if they are to operate at high speeds or are subjected to high accelerations or rapid changes in the direction of load. Under such conditions, the inertia forces of the rollers and cage, and the friction in the lubricant, can have a detrimental influence on the rolling conditions in the bearing arrangement and may cause damaging sliding movements to occur between the rollers and raceways.

The requisite minimum radial load to be applied to standard tapered roller bearings can be estimated from

Frm = 0, 02 C Where

minimum radial load, kN
basic dynamic load rating, kN (see product table)

When starting up at low temperatures or when the lubricant is highly viscous, even greater minimum loads may be required. The weight of the components supported by the bearing, together with external forces, generally exceeds the requisite minimum load. If this is not the case, the single row tapered roller bearing must be subjected to an additional radial load, which can be achieved easily by applying preload. For additional information, refer to the section “Bearing preload”.

Equivalent dynamic bearing load

Fr when Fa/Fr =re
0, 4 Fr + Yfa when Fa/Fr >re
The values of the calculation factors e and Y
can be found in the product tables.

Equivalent static bearing load

P0 = 0, 5Fr + Y0Fa
When P0 < Fr, P0 = Fr should be used. The value of the calculation factor Y0 can be found in the product table.

Determination of axial load When a radial load is applied to a single row tapered roller bearing, the load is transmitted from one raceway to the other at an angle to the bearing axis and an internal axial force will be produced in the bearing. It must be considered when calculating the equivalent bearing loads for bearing arrangements consisting of two single bearings and/or bearing pairs arranged in tandem.

The necessary equations are provided in table 3 for the various bearing arrangements and load cases. The equations are only valid if the bearings are adjusted against each other to practically zero clearance, but without any preload. In the arrangements shown, bearing A is subjected to a radial load FrA and bearing B to radial load FrB. Values of the loads FrA and FrB are always considered positive even when they act in the direction opposite to that shown in the figures. The radial loads act at the pressure centres of the bearings (dimension a in the product table).

In addition to an external force Ka acts on the shaft (or on the housing). Cases 1c and 2c are also valid when Ka = 0. Values of the factor Y can be found in the product table.

WD Tapered Roller Bearings have tapered inner and outer ring racesways between which tapered rollers are arranged.Both of which have single and double row structures.With the higher precision than P5 standard, they have high dimension and running accurancy accordingly. Tapered roller bearings with high speed and long lifespan are always used in Automobile, Gearbox, Main shaft of machine tool, Construction machineries, Rolling mill equipment.

Bearing Code 30220
d 100
D 180
B 34
C 29
T 37
R2smin 3
R4smin 2.5
Mkg 3.81
CrkN 250
CorkN 325
E 0.42
Y 1.4
YO 0.8
n1/min 2000
D1max 116
D2max 112
D3min 157
D4min 168

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Contact Information
  • Company Name:WD Bearing Group
  • Contact Person:Mr Huang David
  • Telephone:86-510-82791933
  • Fax:86-510-82718635
  • Email:
  • Country/Territory:China
  • Address:20 Zhengyang Road, Qingyang Industr
  • Zipcode:214400
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