Friction reduction on powertrains by polyglycols, alternative steels and/or thin films

摘要

The contribution of thin films, such as diamond like carbons (DLCs), to reduce friction undermixed/boundary conditions in highly concentrated contacts entered into focus. This is the moreso, as their slip-rolling resistance became pertinent, proven and repeatable in particular frombatch to batch. Therefore, using such coatings to reduce power losses in the whole power-trainreceives a dramatically increasing priority. The actual benchmark covers slip-rolling contactsabove FZG 14 (P_(0max) > 2,170 MPa) lubed by a factory fill engine oil (SAE 0W-30; ν~(120℃)= 5.33mPas; HTHS~(150℃)= 3.0 mPas) at 120℃. These parameters are typical for power-train applications(not the oil). The present benchmark illuminates the tribological impact on friction, wear andslip-rolling resistance as well as load carrying capacity of commonly used uncoated bearingsteels and uncoated alternative steel alloys in comparison to high performance thin film coatings(e.g. a-C, ta-C, Zr(C,N)). This benchmark suggests a change in philosophy. Rather than prescribingspecific oils, formulated to specifically reduce the friction of thin films, better resultscan be obtained, if the uncoated steel metallurgy and the thin films can respond uniformly tocommon, hydrocarbon-based engine oil formulations used by end-users.