DIN ISO 14635-3:2011-08

Zahnräder - FZG-Prüfverfahren - Teil 3: FZG-Prüfverfahren A/2,8/50 zur Bestimmung von relativer Fresstragfähigkeit und Verschleißverhalten von Getriebefließfetten (ISO 14635-3:2005) Gears - FZG test procedures - Part 3: FZG test method A/2,8/50 for relative scuffing load-carrying capacity and wear characteristics of semifluid gear greases (ISO 14635-3:2005) Engrenages - Méthodes d'essai FZG - Partie 3: Méthode FZG A/2,8/50 pour évaluer la capacité de charge au grippage et les caractéristiques d'usure des graisses d'engrenages semi-fluides (ISO 14635-3:2005) Lubricating oil is mainly used in highly stressed gears. However, semifluid gear greases are becoming increasingly important here. The test standards DIN ISO 14635-1 and DIN ISO 14635-2 deal with the determination of the scuffing load-carrying capacity of gear oils. DIN ISO 14635-3 describes a test method based on an FZG four-square test machine for determining the relative load-carrying capacity of semi-fluid gear greases defined by the gear surface damage known as scuffing. The test method described here is applicable for semi-fluid gear greases of NLGI classes 0 to 000, typically used with highly stressed gearing for enclosed gear drives. It can only be applied to greases giving a sufficient lubricant flow in the test gear box of the FZG test machine. A defined set of test gears, the weight of which was determined prior to the test, is run with the test lubricant at constant speed for a fixed number of revolutions and a defined temperature in dip lubrication mode. Loading of the gear teeth is increased step-by-step in a maximum of 12 load stages until the failure criteria is reached or the test is completed without reaching the failure criteria. After load stage 4, the pinion tooth flanks are visually inspected for surface damage and the weight loss of the gear set is determined. The test is considered complete when either the failure criteria have been met or when load stage 12 is run without meeting the failure criteria.