LUBRICANT COMPOSITION

PROBLEM TO BE SOLVED: To provide an ashless load resistant lubricant composition excellent in thermal stability and water proofness useful from both an aspect of environment protection or safety and practical performance of the lubricant, and further having excellent extreme pressure property and abrasion resistance even under high load severe environment.SOLUTION: There is provided a lubricant composition containing a lubricant base oil, a phosphorus compound represented by the formula (1) of 10 to 10000 mass.ppm based on the total amount of the composition in terms of phosphorus amount. In the formula (1), Rand Rrepresents a hydrocarbon group having 2 to 18 carbon atoms, Rrepresents a hydrocarbon group having 1 to 4 carbon atoms and Rrepresents a hydrogen atom or a hydrocarbon group having 1 or more carbon atom. 【課題】環境保護や安全性の面と潤滑油の実用性能の両面から有用な、熱安定性・耐水性に優れ、さらには高荷重の過酷な環境下でも優れた極圧性および耐摩耗性を有する無灰の耐荷重性潤滑油組成物を提供する。【解決手段】潤滑油基油、および式（１）で表されるリン化合物を、組成物全量基準、リン量換算で１０〜１００００質量ｐｐｍ含有する潤滑油組成物。【化１】（式中、Ｒ１、Ｒ２は炭素数２〜１８の炭化水素基、Ｒ３は炭素数１〜４の炭化水素基、Ｒ４は水素原子または炭素数１以上の炭化水素基を示す。）【選択図】なし