The Design of Rolling Bearing Mountings

89 Drive unit of a finished goods elevatorFinished-goods elevators are used, for example, forcharging salt granulating plants. The material isconveyed in buckets attached to a chain. The chain isdriven by the tumbler situated at the upper end.Operating dataInput power 22 kW; speed 13.2 min –1 ; radial bearingload 90 kN.Bearing selectionAs shaft deflections and misalignments have to be expectedthe drive shaft is supported on self-aligningbearings. Selecting split spherical roller bearings FAG222SM125T ensures that the heavy drive unit withthe torque arm does not have to be dismounted in theevent of repair.As a result, the downtimes of the plant and the cost ofproduction loss are considerably lower than theywould be with one-piece bearings. To limit the varietyof bearings used, a split spherical roller bearing wasprovided at the free shaft end as well.Split spherical roller bearings have a cylindrical bore.Inner ring, outer ring and cage with roller set are splitinto halves.The split inner ring halves are braced together bymeans of four dowel screws and attached to the shaft.Both outer ring halves are fitted together without a gapby means of two dowel screws.The drive-end bearing is mounted with two locatingrings and acts as the locating bearing; the bearing at theopposite end is the floating bearing. Split spherical rollerbearings FAG 222SM125T are designed in such away that they can be mounted into split series housingsFAG SNV250 instead of one-piece spherical rollerbearings with an adapter sleeve. Outside diameter, outerring width and shaft seat diameter are identical.The theoretical fatigue life L h of the bearings is over100,000 hours.Machining tolerancesShaft to h6...h9;housing to H7Lubrication, sealingThe bearings are lubricated with grease. The housingsare connected to a central lubricating system so thatcontinuous relubrication is ensured.The shaft openings on both sides of the housing areeach sealed by a two-lip seal.89: Drive unit of a finished goods elevatorFAG 126