Slide bearings - Wolf Kunststoff-Gleitlager GmbH

CCCCCC13.5.5. Calculation of the permissible pv-value:Mathematical exampleIn order to calculate the permissible pv-value (pv zul) of the radial slide bearing we have to determine the followingcorrection factors:Prefacek Sch: correction factor for lubrication taken from ill. 24 on dry run k Sch= 1k ϑ: correction factor for ambient temperature, at an ambient temperature of 65°C and with thematerial ZX-324V2T taken from ill. 25 k J= 0,6 .k bd: correction factor for the relation b/d (width / diameter) of the bushing with b/d = 30 mm / 30 mm= 1 follows from ill. 26 k bd=0,75k d: correction factor for the screw diameter d. Ill. 27 with a screw diameter d of 30 mm revealsk d= 0,3.k Geo: the correction factor for the geometry of the bushing is calculated by means of formula (18);from k Geo= k bd·k dresults 0,75·0,3 = 0,225k SP: correction factor for the installation bearing clearance. As this application does not require areduced installation bearing clearance we choose the “standard” class.From ill. 28 with a sliding speed of 0,5 m/min reveals k SP=1: taken from section 13.5.4.1 = 27,5 N/mm² · m/minpvnomzulThe permissible pv-value of the radial slide bearing is determined by means of formula (17).pvzul= pvnom zul⋅ kSch⋅ kϑ⋅ kGeo⋅ k13.5.6. Checking the pv-value:Sp⇒N27,5mm²⋅mmin⋅1⋅0,6 ⋅ 0,225 ⋅1=N3,71mm²⋅mminContentsMaterialoverviewDesignguidelinesMathematicalexampleIn order to avoid a thermal overloading ot the slide bearing the following condition (8) must be fulfilled:pvED ≤ pv zulpvED≤ pvzul⇒N3,07mm²⋅mmin≤N3,71mm²⋅mminwith:pv ED: taken from 13.5.4 = 3,07 N/mm² * m/minpv zul: taken from 13.5.5 = 3,71 N/mm² * m/minerfüllt!As the condition (8) is fulfilled we do not reckon with a thermal overloading.13.5 7. Calculation of the emerging temperatures:13.5.7.1 Calculation of the factor kpv by means of formula (19b):pvkpv =pvN3,71mm²N3,07mm²mminmminzul⇒=EDwith:pv zul: taken from section 13.5.5.pv ED: taken from section 13.5.4.1,21TribologyConditions ofinstallationSlide bearings(cylindrical)Slide bearings(with collar)IndexWolf Kunststoff-Gleitlager GmbH • Heisenbergstr. 63 - 65 • 50169 Kerpen-Türnich • Tel. 02237/9749-0 • Fax. 02237/9749-2046