Lubricating oil composition for shock absorber

Patent metadata

Field	Value
Publication number	US-9745536-B2
Application number	US-201414910893-A
Country	US
Kind code	B2
Filing date	Aug 25, 2014
Priority date	Aug 23, 2013
Publication date	Aug 29, 2017
Grant date	Aug 29, 2017

Abstract

The lubricating oil composition for a shock absorber of the present invention contains (A) a base oil composed of a mineral oil and/or a synthetic oil, (B) a tertiary amine represented by the following general formula (I), and (C) a zinc dithiophosphate represented by the following general formula (II):

wherein R 1 and R 2 each independently represent an aliphatic hydrocarbon group having from 1 to 5 carbon atoms, and R 3 represents an aliphatic hydrocarbon group having from 12 to 24 carbon atoms in the general formula (I),

wherein R 4 to R 7 each independently represent one selected from an alkyl group and an alkenyl group each having 1 to 24 carbon atoms in the general formula (II).

First claim

The invention claimed is:

1. A lubricating oil composition for a shock absorber, comprising (A) a base oil composed of a mineral oil and/or a synthetic oil, (B) from 0.01 to 3% by mass of a tertiary amine represented by the following general formula (I), (C) from 0.01 to 3% by mass of a zinc dithiophosphate represented by the following general formula (II):

wherein R 1 and R 2 each independently represent an aliphatic hydrocarbon group having from 1 to 5 carbon atoms, and R 3 represents is a linear, branched or cyclic alkyl group having from 16 to 20 carbon atoms in the general formula (I),

wherein R 4 to R 7 each independently represent one selected from a linear, branched or cyclic alkyl group having from 6 to 10 carbon atoms in the general formula (II),
(D) from 0.001 to 0.1% by mass of a polydimethylsiloxane foaming agent having a kinematic viscosity at 20° C. of from 0.5 to 15 mm 2 /s, and
(E) from 0.0001 to 0.01% by mass of a fluorinated polysiloxane anti-foaming agent having a kinematic viscosity at 20° C. of from 200 to 2,000 mm 2 /s.

2. The lubricating oil composition for a shock absorber according to claim 1 , wherein R 3 in the general formula (I) is a stearyl group.

3. The lubricating oil composition for a shock absorber according to claim 1 , which is a lubricating oil composition for a shock absorber for cars.

4. The lubricating oil composition for a shock absorber according to claim 1 , wherein R 1 and R 2 in the general formula (I) each have 1 or 2 carbon atoms.

5. The lubricating oil composition for a shock absorber according to claim 1 , wherein R 1 and R 2 each have one or two carbon atoms, and R 3 is a stearyl group in general formula (I).

6. The lubricating oil composition for a shock absorber according to claim 1 , wherein the lubricating oil composition does not contain stearic acid.

7. The lubricating oil composition for a shock absorber according to claim 1 , wherein the lubricating oil composition does not contain a non-fluorinated silicon antifoaming agent.

8. The lubricating oil composition for a shock absorber according to claim 1 , having a friction coefficient μ to bronze of from 0.072 to 0.075.

9. The lubricating oil composition for a shock absorber according to claim 1 , having a worn area in a bronze wear test of from 0.028 to 0.030 mm 2 .

10. A shock absorber comprising the lubricating oil composition of claim 1 .

Assignees

• Idemitsu Kosan Co

Inventors

• Sakanoue Shuichi
• Aoki Aya

Classifications

• C10N2030/70

  Soluble oils · CPC title

• C10M2229/02

  Unspecified siloxanes; Silicones · CPC title

• C10M2215/04

  having amino groups bound to acyclic or cycloaliphatic carbon atoms · CPC title

• C10N2030/18

  Anti-foaming property · CPC title

• C10N2010/04

  Groups 2 or 12 · CPC title