Lubricant composition

Abstract

A lubricating oil composition, containing the following components a base oil (A), a thiadiazole-based compound (B), and a boron-modified alkenyl succinimide (C). A content of the component (B) is less than 0.60 mass % based on a total amount of the lubricating oil composition, a content ratio [B/N] by mass of boron atoms to nitrogen atoms derived from the component (C) is 0.35 or more, and a content of boron atoms derived from the component (C) is 300 ppm by mass or less based on the total amount of the lubricating oil composition.

1 . A lubricating oil composition, comprising the following components:
 a base oil (A);   a thiadiazole-based compound (B), and   a boron-modified alkenyl succinimide (C),   wherein   a content of the component (B) is less than 0.60 mass % based on a total amount of the lubricating oil composition,   a content ratio [B/N] by mass of boron atoms to nitrogen atoms derived from the component (C) is 0.35 or more, and   a content of boron atoms derived from the component (C) is 300 ppm by mass or less based on the total amount of the lubricating oil composition.   
     
     
         2 . The lubricating oil composition according to  claim 1 , wherein a content of nitrogen atoms derived from the component (C) is 320 ppm by mass or less based on the total amount of the lubricating oil composition. 
     
     
         3 . The lubricating oil composition according to  claim 1 , wherein a content of nitrogen atoms derived from the component (C) is 5.0 to 320 ppm by mass based on the total amount of the lubricating oil composition. 
     
     
         4 . The lubricating oil composition according to  claim 1 , wherein the content ratio [B/N] by mass of boron atoms to nitrogen atoms derived from the component (C) is 0.35 to 2.0. 
     
     
         5 . The lubricating oil composition according to  claim 1 , wherein the content of boron atoms derived from the component (C) is 3.0 to 300 ppm by mass based on the total amount of the lubricating oil composition. 
     
     
         6 . The lubricating oil composition according to  claim 1 , wherein the component (C) comprises a boron-modified alkenyl bis-succinimide (C1). 
     
     
         7 . The lubricating oil composition according to  claim 1 , wherein the component (B) comprises a thiadiazole-based compound (B1) having a branched chain alkyl group. 
     
     
         8 . The lubricating oil composition according to  claim 1 , wherein a content of a sulfurized olefin is less than 0.20 mass % based on the total amount of the lubricating oil composition. 
     
     
         9 . The lubricating oil composition according to  claim 1 , wherein a kinematic viscosity of the lubricating oil composition at 100° C. is 2.1 mm 2 /s or more and less than 5.0 mm 2 /s. 
     
     
         10 . The lubricating oil composition according to  claim 1 , further comprising a component (D) one or more phosphorus-based compounds (D) selected from a phosphoric acid ester and a phosphorous acid ester. 
     
     
         11 . The lubricating oil composition according to  claim 10 , wherein the component (D) comprises one or more sulfur-phosphorus-based compounds (D1) selected from a sulfur atom-containing phosphoric acid ester and a sulfur atom-containing phosphorous acid ester. 
     
     
         12 . A method of lubricating a speed reducer, comprising:
 applying the lubricating oil composition of  claim 1  to the speed reducer.   
     
     
         13 . A speed reducer to which the lubricating oil composition according to  claim 1  has been applied. 
     
     
         14 . (canceled)