Text version of the page

Definitions

Operatingtemperatures Swivelling angle Nominal service life

The swiveling angle is the excursion ofthe rod end from one final position to the other.Half the swiveling angle The term »nominal service life« is used for DURBAL heavy-duty antifriction bearing rod ends and represents thenumber of swivelling motions or rotations and/or the number of service hours the rod end performs before showing the first signs of material fatigue at the raceway or roller bodies.In view of many influence factors that are difficult or impossible to assess, the service life of several obviously identical bearings differ under the same operating conditions.For this reason, thefollowing method for the service lifedetermination of DURBAL heavy-duty antifriction rod ends results in a nominal service life being achieved or exceeded by at least 90 % of a largerquantity of identical rod ends. DURBAL heavy-duty antifriction bearingrod ends can be used for operating temperatures between – 20 °C and + 120 °C. C2 . isused to calculate the service or workinglife. The temperature range of DURBAL heavy-duty rod ends with integral sphe- rical plain bearing is between – 30 °Cand + 60 °C, without affecting the loadability.Higher temperatures will reduce the loadability taken into account for the calculation of the working life under the temperature factor

Loads

12034 The decisive parameters for the sele c tionand calculation of DURBAL heavy-dutyrod ends are size, direction and type of load. the following calculation procedurewhich is based on numerous resultsfrom endurance test runs and values from decades of experience.The values determined by this formula are achieved, if not exceeded, by the majority of theDURBAL heavy-duty rod ends.

Working life

Radial or combined loads

The DURBAL heavy-duty rod ends havebeen especially designed to adopt highradial loads. They can furthermore be used for combined loads, the axial load share ofwhich does not exceed 20% of the corresponding radial load.

Angle of Misalignment

The term »working life« is used with DURBAL heavy-duty plain bearing rodends.It represents the number of swivelling motions or rotations and/or the number of services hours the DURBAL heavy-duty plain bearing rod end performs before becomingunserviceable because of material fatigue, wear, increased bearing clearance or increase of the bearing friction moment.The working life is notonly influenced by the size and the type of load, it is also affected by a number of factors, which are partially difficult to assess.A calculation of the exact servicelife is therefore impossible.Field-experienced standard values for the approximate working lifecan nevertheless be determined by using The angle of tilt, also called
misalingment angle, refers to the possible excursion ofthe joint ball and/or the inner ring to the rod end axis in degrees.The tilting angle indicated in the table for the DURBAL heavy-duty antifriction bearingrod ends corresponds to the max.Possible excursion being limited by the shields on both sides.It is important that this tilting angle is not exceeded either during installation or operation, as otherwise the shields may be damaged.As far as DURBAL heavy-duty plain bearing rod ends are concerned, distinction is made between the tilting angles

Unilaterally acting load

In this case the load acts only in the same direction, which means that theload area is always in the same bearing section. 1 and 2.If the excursion is not limited by adjacentcomponents, excursion angle 1 canfully be used without affecting the rodend capacity.Tilting angle 2 is theexcursion limit when connecting a forked component.

Alternately acting load

In case of alternating loads, the loadareas facing each other are alternatelyloaded and/or relieved, which means that the load changes its direction constantly by approx.180°.
1

5