Lubricating oil composition, and sliding mechanism using lubricating oil composition

Patent metadata

Field	Value
Publication number	US-9803155-B2
Application number	US-201314383403-A
Country	US
Kind code	B2
Filing date	Mar 18, 2013
Priority date	Mar 16, 2012
Publication date	Oct 31, 2017
Grant date	Oct 31, 2017

Abstract

Disclosed is a lubricating oil composition for low-friction sliding materials, which is used in a sliding mechanism where a DLC film containing hydrogen in an amount of from 5 atom % to 50 atom % is formed on at least one sliding surface. The lubricating oil composition contains, in the lubricant base oil therein and based on the total amount of the composition, (A) an organic zinc dithiophosphate in an amount of from 0.005% by mass to 0.12% by mass in terms of the phosphorus concentration therein, (B) an amine-based friction-reducing agent in an amount of from 0.05% by mass to 5.0% by mass, and (C) an alkaline earth metal salicylate-based detergent and/or an alkaline earth metal sulfonate-based detergent in an amount of from 0.05% by mass to 0.5% by mass in terms of the alkaline earth metal concentration therein, wherein the component (A) contains, based on the total amount of the composition, a zinc primary dialkyldithiophosphate in an amount of from 0.005% by mass to 0.05% by mass in terms of the phosphorus concentration therein.

First claim

The invention claimed is:

1. A lubricating oil composition, comprising a lubricant base oil, wherein the lubricant base oil comprises, based on the total amount of the composition:
(A) an organic zinc dithiophosphate in an amount of from 0.005% to 0.10% by mass in terms of the phosphorus concentration therein;
(B) an amine-based friction-reducing agent in an amount of from 0.1% to 3.0% by mass, wherein the amine-based friction-reducing agent is an adduct of a primary amine having an aliphatic hydrocarbon group having from 16 to 24 carbon atoms with an ethylene oxide;
(C) a calcium salicylate-based detergent and/or a calcium sulfonate-based detergent in an amount of from 0.1% to 0.25% by mass in terms of the alkaline earth metal concentration therein; and
(D) an ashless dispersant comprising a succinic acid imide, a boron-containing succinic acid imide, or mixture thereof,
wherein the organic zinc dithiophosphate (A) comprises, based on the total amount of the composition, a zinc primary dialkyldithiophosphate in an amount of from 0.005% to 0.05% by mass in terms of the phosphorus concentration therein, and
wherein the lubricating oil composition exhibits a friction coefficient of less than or equal to 0.064 when subjected to a frictional property test in which a diamond-like carbon (DLC) coated disc containing 20 atom % of hydrogen is subject to a load of 100 N at a temperature of 100° C. in a reciprocating friction tester operated at an amplitude of 8 mm with a frequency of 10 Hz.

2. A sliding mechanism comprising:
two sliding members that slide to each other, each sliding member having a sliding surface; and
a lubricating oil composition, which is sandwiched between the sliding surfaces of the two sliding members,
wherein at least one sliding surface of the two sliding members is formed from a diamond-like carbon film comprising hydrogen in an amount of 5 to 50 atom %, and the other sliding surface of the sliding material is formed from a DLC material, an iron base, or an aluminum alloy material, and
wherein the lubricating oil composition comprises a lubricant base oil, wherein the lubricant base oil comprises, based on the total amount of the composition:
(A) an organic zinc dithiophosphate in an amount of from 0.005% to 0.10% by mass in terms of the phosphorus concentration therein;
(B) an amine-based friction-reducing agent in an amount of from 0.1% to 3.0% by mass, wherein the amine-based friction-reducing agent is an adduct of a primary amine having an aliphatic hydrocarbon group having from 16 to 24 carbon atoms with an ethylene oxide;
(C) a calcium salicylate-based detergent and/or a calcium sulfonate-based detergent in an amount of from 0.1% to 0.25% by mass in terms of the alkaline earth metal concentration therein; and
(D) an ashless dispersant comprising a succinic acid imide, a boron-containing succinic acid imide, or mixture thereof,
wherein the organic zinc dithiophosphate (A) comprises, based on the total amount of the composition, a zinc primary dialkyldithiophosphate in an amount of from 0.005% to 0.05% by mass in terms of the phosphorus concentration therein.

3. The sliding mechanism of claim 2 , wherein the diamond-like carbon film comprises graphite crystal peaks in a X-ray scattering spectrum.

4. The sliding mechanism of claim 3 , wherein a crystal diameter of the graphite crystal in the diamond-like carbon film is 15 nm to 100 nm.

5. The sliding mechanism of claim 2 , wherein the diamond-like carbon film is formed in a high-density plasma atmosphere by a cathode PIG plasma CVD method.

Assignees

• Idemitsu Kosan Co

Inventors

• Koshima Hiroaki
• Kasai Moritsugu
• Ogahara Yoko
• Tsujioka Masanori
• Miyake Koji

Classifications

• C10M2215/082

  containing hydroxyl groups; Alkoxylated derivatives · CPC title

• C10M2219/046

  Overbased sulfonic acid salts · CPC title

• C10M2207/289

  containing free hydroxy groups · CPC title

• C10M141/10 Primary

  at least one of them being an organic phosphorus-containing compound · CPC title

• C10N2030/42

  Phosphor free or low phosphor content compositions · CPC title