Low-friction sliding mechanism including lubricant composition

Abstract

The present invention provides a low-friction sliding mechanism comprising a lubricant composition on a sliding plane between a DLC-coated sliding member (A) and a sliding member (B), wherein the DLC-coated sliding member (A) is formed by coating a base material with diamond-like-carbon containing 10 atom % or less of hydrogen, the sliding member (B) includes at least one kind of material selected from the group consisting of a metal material, a non-metal material, and a metal or non-metal coated material having a surface coated with a thin film, and the lubricant composition contains a basic oil (C), PAG (D), and an acid oxygen-containing organic compound (E) with an acid number of more than 1 mgKOH/g.

1 . A low-friction sliding mechanism comprising a lubricant composition on a sliding plane between a DLC-coated sliding member (A) and a sliding member (B), wherein: the DLC-coated sliding member (A) is formed by coating a base material with diamond-like-carbon containing 10 atom % or less of hydrogen; the sliding member (B) includes at least one kind of material selected from the group consisting of a metal material, a non-metal material, and a metal or non-metal coated material having a surface coated with a thin film; and the lubricant composition contains a basic oil (C), PAG (D), and an acid oxygen-containing organic compound (E) with an acid number of more than 1 mgKOH/g. 
     
     
         2 . The low-friction sliding mechanism according to  claim 1 , wherein the diamond-like-carbon contains 0.5 atom % or less of hydrogen. 
     
     
         3 . A low-friction sliding mechanism comprising a lubricant composition on a sliding plane between a DLC-coated sliding member (A) and a sliding member (B), wherein: the DLC-coated sliding member (A) is formed by coating a base material with a-C diamond-like-carbon without hydrogen; the sliding member (B) includes at least one kind of material selected from the group consisting of a metal material, a non-metal material, and a metal or non-metal coated material having a surface coated with a thin film; and the lubricant composition contains a basic oil (C), PAG (D), and an acid oxygen-containing organic compound (E) with an acid number of more than 1 mgKOH/g. 
     
     
         4 . The low-friction sliding mechanism according to  claim 1 , wherein: the metal material of the sliding member (B) is at least one kind of material selected from the group consisting of a material containing iron, a material containing aluminum alloy, and a material containing magnesium alloy; and the coated material is formed by being coated with the thin film of at least one kind of material selected from the group consisting of DLC and ceramics. 
     
     
         5 . The low-friction sliding mechanism according to  claim 1 , wherein: the PAG (D) is at least one kind selected from the group consisting of polyethylene glycol, polypropylene glycol, and polybutylene glycol, and the PAG (D) has a weight-average molecular weight of from 200 to 10,000. 
     
     
         6 . The low-friction sliding mechanism according to  claim 1 , wherein the PAG (D) is present in an amount in the range of from 0.1 to 20.0% based on the entire amount of the lubricant composition. 
     
     
         7 . The low-friction sliding mechanism according to  claim 1 , wherein the acid oxygen-containing organic compound (E) has a carbon number of from 8 to 1,000. 
     
     
         8 . The low-friction sliding mechanism according to  claim 1 , wherein the acid number of the acid oxygen-containing organic compound (E) is 1.2 mgKOH/g or more. 
     
     
         9 . The low-friction sliding mechanism according to  claim 1 , wherein the lubricant composition contains the acid oxygen-containing organic compound (E) in an amount in the range of from 0.05 to 5.0% based on the entire amount of the lubricant composition, and the acid oxygen-containing organic compound (E) contains at least one kind selected from the group consisting of alcohols, esters, ethers, ketones, aldehydes, carbonates, and derivatives thereof. 
     
     
         10 . A lubricant system comprising the low-friction sliding mechanism according to  claim 1 .