Slide bearings - Wolf Kunststoff-Gleitlager GmbH

CCCCCC13.5.12. Estimation of working lifeMathematical exampleThe determination of working life requires the total wear rate, which can be calculated by means of formula(23):PrefaceSG = S N ⋅ kϑ⋅kpin which:S N: nominal wear rate, from ill. 30 follows a wear rate of 11 µm/km at a roughness height of the screw of 8 µmRZ and the material ZX-324V2Tkϑ: correction factor for temperature, from ill. 31 follows kϑ = 0,3 at a sliding surface temperature of 85 °Ck p: from ill. 32 follows k p= 40 with a surface pressure of 66 N/mm 2follows:µmµmSG = SN⋅ kϑ⋅kp= 11 ⋅ 0,3 ⋅ 40 = 132kmkmThe expected working life for point load then yields from formula (21):ContentsMaterialoverviewDesignguidelinesL∆D− ∆h− Se=0,06 ⋅ v ⋅ S15000,06 ⋅[ µm] − 151,5 [ µm] − 229 [ µm]0,47 [ m/ min] ⋅132[ µm /km]maxP⇒=Gin which:∆D = permissible screw displacement – In this application case a permissible screw displacement of 1,5 mmhas been determined by the construction department. –300hMathematicalexampleThis corresponds to a transit time of 15 s per stroke for about 72000 strokes.13.5.13. Summary of the resultsmaterial chosenZX-324V2Tclass of bearing clearancesstandardinside diameter of the bushing d1 30 mmoutside diameter of the bushing d2 36 mmbushing width b1 30 mmsurface pressure p 66,66 N/mm 2sliding speed v 0,5 m/minmaximum pv-value pv 33,33 N/mm 2 * m/minswitch-on duration ED 4,76 %pv-value at ED pv ED3,07 N/mm 2 * m/minpermissible pv-value pv zul3,71 N/mm 2 * m/minsliding surface temperature ϑ GF85 °Cslide bearing temperature ϑ L75 °Ccasing temperature ϑ G70 °Cpermissible casing temperature ϑ Gzul130 °Cnecessary mold bearing clearance ∆S ϑZ-0,0851 mmminimum mold bearing clearance Se min0,130 mmmaximum mold bearing clearance Se max0,229 mmwave cavity caused throughdeformations ∆h 0,1515 mmworking life L P300 h = 72000 strokesTribologyConditions ofinstallationSlide bearings(cylindrical)Slide bearings(with collar)IndexWolf Kunststoff-Gleitlager GmbH • Heisenbergstr. 63 - 65 • 50169 Kerpen-Türnich • Tel. 02237/9749-0 • Fax. 02237/9749-2050