Skuteczność działania smarów plastycznych przy zmiennych wartościach obciążenia i prędkości poślizgu

Przedstawiono wyniki badań tribologicznych skuteczności działania wybranych smarów plastycznych. Oceny dokonano na podstawie testów przeprowadzonych przy zmiennych wartościach obciążenia i prędkości poślizgu. Zbadano 8 różnych smarów plastycznych, przy czym 7 z nich to smary będące w handlu. Eksperyment prowadzono na aparacie czterokulowym metodą planowanego eksperymentu z wykorzystaniem planu rotalnego na 5 poziomach. Dla każdego z wytypowanych smarów została opracowana funkcja regresji, która uzależniała zużycie od prędkości poślizgu i obciążenia nadanego. Skuteczność badanych smarów oceniano według kryterium wartości objętości funkcji zużycia.

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The results of tribological research concerning the efficiency of lubrication of some selected greases are presented. The efficiency was evaluated based upon tests carried out under fluctuating load and sliding speed. Eight different grease lubricants were tested (seven of theses are commercially available). The last one was an own compositions made by the authors': the 1S vehicle grease with 6% of PTFE powder. The employed powder was suspended Tarflen (20 žm to 40 žm granulation) manufactured by Z. A. Tarnów. The testing was carried out using a four ball apparatus under a rotatable experimentation plan at 5 levels, which provides a constant estimate of the regression function. Independent variables were the load F and the slip speed [ni]. Dependent variables were the wear d measured as a diameter of a smudge circle on the stationary balls. The measurements were done after some 33.5 meters of the friction distance. The assumed friction distance equals the distance covered by the mobile ball under a standard four ball testing for limiting wear index Goz. The tests were carried out under fluctuating loading (32 to 128 daN) and slip speed (0.12 to 0.68 m/s). For mathematical description of the input/output data the regression analysis was used. A bi-polynomial with the first grade support served as an approximation function. For each of the selected greases a regression function was worked put, which relates the wear with the load and slip speed. The efficiency of the tested greases was evaluated using a volume wear function. The lower is the value, the more efficient is a grease. According to the research, the least efficient was the 1S grease and the most efficient, the Litmos EP-25 grease.