The Design of Rolling Bearing Mountings

92 Double toggle jaw crusherDouble toggle jaw crushers have a large mouth opening.They are used, for example, as primary crushers toprepare ballast for road building. The coarse crushingis followed by further crushing operations until an aggregateof the size and shape required, e.g. gravel orgrit, is obtained.Operating dataInput power 103 kW; speed of eccentric shaftn = 210 min –1 ; mouth opening 1,200 x 900 mm;eccentric radius 28 mm.Bearing selection, dimensioningSwing jawMachining tolerancesEccentric shaftPitmanThe pitman is fitted to the eccentric part of the horizontalshaft and actuates the swing jaw through a doubletoggle lever system. The inner bearings supportingthe pitman must accommodate heavy crushing loads.The outer bearings transmit, in addition to theseloads, the flywheel weight and the circumferentialloads resulting from the drive. Due to the high loadingand the rugged operation, spherical roller bearings arechosen. Spherical roller bearings FAG 23260K.MB aremounted as outer bearings and FAG 23176K.MB asinner bearings. The pitman bearing arrangement is ofthe floating bearing type. The outer bearing arrangementfeatures a locating bearing at the drive side andthe floating bearing at the opposite side. With an indexof dynamic stressing f L ≈ 4.5 the bearing arrangement issafely dimensioned with regard to nominal rating life.The bearings are mounted on the shaft with adaptersleeves FAG H3260HGJ and FAG H3176HGJ, respectively.The bearing seats on the shaft are machinedto h7 with a cylindricity tolerance IT5/2 (DIN ISO1101), and the bores of housing and pitman to H7.Lubrication, sealingGrease lubrication with a lithium soap base grease ofpenetration class 2 wit EP additives (FAG rolling bearinggrease Arcanol L186V). The relubrication intervalfor the bearings is 2...3 months.The bearings are sealed by multiple labyrinths. Once ortwice a week, fresh grease is injected into the labyrinths.Locating bearingFloating bearing92: Bearing mounting of a double-toggle jaw crusherFAG 130