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.

Claims

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.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0006] An aspect of the present invention is a low-friction sliding mechanism including a lubricant composition on a sliding plane between a DLC-coated sliding member (A) and a sliding member (B). The DLC-coated sliding member (A) is formed by coating a base material with diamond-like-carbon (DLC) 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. 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.

[0007] Preferably, the diamond-like-carbon contain 0.5 atom % or less of hydrogen.

[0008] A further embodiment of the present invention is a low-friction sliding mechanism including a lubricant composition on a sliding plane between a DLC-coated sliding member (A) and a sliding member (B). In this embodiment, 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. 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.

[0009] Preferably in the low-friction sliding mechanism of the present invention, 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. 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.

[0010] Also preferably, the PAG (D) is at least one kind selected from the group consisting of polyethylene glycol, polypropylene glycol, and polybutylene glycol. The PAG (D) has a weight-average molecular weight of from 200 to 10,000.

[0011] In an embodiment of the present invention, 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.

[0012] Preferably, the acid oxygen-containing organic compound (E) has a carbon number of 8 to 1,000.

[0013] Also preferably, the acid number of the acid oxygen-containing organic compound (E) is 1.2 mgKOH/g or more.

[0014] Preferably, in the low-friction sliding mechanism of the present invention, 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 lubricant composition. It is also preferred that 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.

[0015] The present invention also provides a lubricant system including the low-friction sliding mechanism as described herein.

[0016] According to any of the aspects of the present invention, the function of reducing the friction of DLC can be further increased by adding an acid oxygen-containing organic compound to a system with PAG added to a basic oil.