Linear Positioners Catalog_en-US_revA - Kollmorgen

N2 Dual Rod-End Bearing OptionDB Dual Rod-End BearingOur standard N2 Series electric cylinder contains a single rodendbearing. The dual rod-end bearing (DB) option increasesthrust tube side load capacity and reduces undesirable thrusttube runout, while reducing the stroke by 1.5 inches. (All ECSeries cylinders are equipped with a dual rod-end bearingautomatically, so this option does not apply to them.)DB available with:• N2 Series 12 inch stroke and belowDB required with:• N2 Series above 12 inch strokeNotes:• The DB option reduces stroke by 1.5 inches(e.g. 18” with DB yields only 16.5” actual stroke.)Side LoadAll Kollmorgen electric cylinders are designed to withstand alimited amount of side load on the thrust tube. The thrust tubein a standard N2 Series cylinder is supported by a single rodendbearing and by a patented internal guide assembly. Thisbearing system has a limited capacity to handle side loads,shown in the curve below.When increased side load capacity or stiffness is required, orwhen moving a load that is not externally supported, the dualrod-end bearing (DB) option is recommended. This option addsa second thrust tube rod-end bearing for additional support,while subtracting 1.5 inches from the available stroke. N2models above 12 inches stroke require the DB option.Another means of increasing side load capacity is to use thehigher capacity EC series, which includes the dual rod-endbearing in its standard configuration.Standard N2 Cylinder (Single Bearing)DB Option (Dual Bearings)Actual Travel Reducedby 1.5 InchesRunoutThe -DB option reduces thrust tube runout by lengthening thethrust tube support bearing in the rod-end housing.Kollmorgen recommends the DB option to reduce runoutwhenever the thrust tube is the only means of guiding the load.Performance improvement is most observable for cylinderswith stroke length above 12 inches, or whenever runout iscritical as the thrust tube approaches full extension.For the least amount of runout possible for a standard product,specify the DB option and also increase the stroke of thecylinder while “short-stroking” the unit.If the load is guided externally by linear bearings, thestandard bearing is preferred since it allows greater mountingmisalignment and minimal friction.Top or Side ofCylinder HousingSide Load Moment(in-lbs)Side Load (lbs)L I N E A R P O S I T I O N E R SN2 Series — Side Load Capacity vs. Extended LengthN359337Lb8075-DB MAXExtend Distance(inches)Runout311702892676560Selection CriteriaSide Load2452222001781561331118967442205550454035302520151050002.564STANDARD MAX12 -DB8 -DB6 -DB6, 4, 2 84 -DB12 18 -DB5 7.5 10 12.5 15 17.5 20 in127 191 254 318 381 445 508 mmExtended LengthDB OptionWhen using clevis or trunnion mountStandardWhen rigidlymounted>12 in