Influence of a roller-bearing load to its operating temperature

Doba trajanja kotalnega ležaja je odvisna od obremenitve, obratovalne temperature, pogojev okolja. Povišana obratovalna temperatura lahko predstavlja ključni razlog za predčasno odpoved ležaja. Razlogi za povišano temperaturo so lahko obremenitev ležaja, način vgradnje, kvaliteta mazanja, temperatura okolice itn. V tej nalogi smo se posvetili konstruiranju preizkuševališča za ležaje, na katerem smo merili stacionarno obratovalno temperaturo ležaja pri različnih obremenitvah. Silo obremenjevanja smo merili z merilnimi uporovnimi lističi in obratovalno temperaturo ležaja z uporovnim temperaturnim zaznavalom. Ugotovili smo, da se pri konstantni vrtilni hitrosti ležaja 600 obr/min in temperaturi okolice med 20 in 23 °C, stacionarna obratovalna temperatura ležaja povečuje z večanjem obremenitve. Pri teh pogojih naj obremenitev ne bi presegla 25 % dinamične radialne nosilnosti ležaja, če želimo doseči ciljno dobo trajanja, saj je stacionarna obratovalna temperatura ležaja v tem primeru rahlo pod 70 °C. Pri višjih obratovalnih temperaturah pride do odpovedi ležajne masti, kar lahko privede do obrabe in predčasne odpovedi ležaja.Roller bearing rated life depends on operating conditions such as load, working temperature, enviroment conditions. Increased working temperature may lead to a premature bearing failure. Causes for the increased working temperature may be load of the bearing, mounting type, grease quality, room temperature etc. In this thesis test rig is presented with strain gauges for measuring load on the bearing and resistance temperature sensor for measuring working temperature of the bearing. It was found out that stationary working temperature of the bearing increases with a load increase at 600 rpm bearings rotation speed and room temperature between 20 and 23 °C. In this conditions the bearing load should not exceed 25 % of bearing dynamic radial load. Otherwise, stationary working temperature of the bearing would surpass 70 °C, which would lead to bearings grease failure and consequently premature bearing failure