GREASE COMPOSITION FOR ROLLING BEARING

• Main Authors: OKUDA YUKARI, WATANABE KAZUYA, HIRANO TAKAHIRO, NAGANO KATSUMI, FUJIMAKI YOSHITOMO, FUJII AKIRA, KONDO MASAYUKI, MUKAI HISAYOSHI, KATO SHOTA, TANAKA KEIJI
• Format: Patent
• Language: English; Japanese
• Published: 01.11.2018
• Subjects: CHEMISTRY; FUELS; LUBRICANTS; LUBRICATING COMPOSITIONS; METALLURGY; PEAT; PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; USE OF CHEMICAL SUBSTANCES EITHER ALONE OR AS LUBRICATINGINGREDIENTS IN A LUBRICATING COMPOSITION

To provide urea grease that maintains basic properties such as heat resistance and water resistance required of grease for a bearing used in a machine of an iron-manufacturing facility and has a function of sufficiently forming a grease lubrication film especially under a severe lubrication condition such as a low speed and high load condition to prevent fatal stepped wear from occurring on the raceway surfaces of the inner and the outer rings of a bearing.SOLUTION: There is provided a urea grease composition for a rolling bearing, comprising a diurea thickening agent represented by formulae (a) to (c), base oil of a dynamic viscosity at 40°C of 150 to 400 mm/sec and of a viscosity index of lower than 120, i.e., mineral oil belonging to the group 1 or the group 2 of the API classification, and a specific amount of calcium salicylate and calcium sulfonate, which grease composition is of specific consistency and is suitable for a low speed rotary bearing. (a) RNHCONHRNHCONHR, (b) RNHCONHRNHCONHR, (c) RNHCONHRNHCONHR, (Ris a diphenylmethane residue; Ris a 6-10C saturated hydrocarbon group; and Ris a 12-18C saturated hydrocarbon group).SELECTED DRAWING: None 【課題】耐熱性や耐水性等の製鉄設備機械軸受用グリースに求める基本的な性能を保持し、特に低速、高荷重の厳しい潤滑条件下で、グリース潤滑膜が十分に形成でき、軸受内外輪の起動面で生ずる致命的な段付き摩耗を抑制する機能を持つウレアグリースの提供。【解決手段】式（ａ）〜（ｃ）で表されるジウレア増ちょう剤と基油の４０℃動的粘度が１５０〜４００ｍｍ２／ｓｅｃで、粘度指数が１２０未満のＡＰＩ分類グループ又は２に属するの鉱物油とを含み、特定量のカルシウムサリシレート及びカルシウムスルホネートを含む特定ちょう度のグリース組成物を低速回転軸受に適用する、ころがり軸受用ウレアグリース組成物。（ａ）Ｒ１ＮＨＣＯＮＨＲ２ＮＨＣＯＮＨＲ１（ｂ）Ｒ３ＮＨＣＯＮＨＲ２ＮＨＣＯＮＨＲ３（ｃ）Ｒ１ＮＨＣＯＮＨＲ２ＮＨＣＯＮＨＲ３（Ｒ２はジフェニルメタン残基；Ｒ１はＣ６〜１０の飽和炭化水素基；Ｒ３はＣ１２〜１８の飽和炭化水素基）【選択図】なし