Low-friction sliding mechanism

• US 8,152,377 B2
• Filed: 07/13/2010
• Issued: 04/10/2012
• Est. Priority Date: 11/06/2002
• Status: Active Grant

• Current Assignee: Nippon Oil Corporation (ENEOS Holdings, Inc.), Nissan Motor Co., Ltd.
• Original Assignee: Nippon Oil Corporation (ENEOS Holdings, Inc.), Nissan Motor Co., Ltd.
• Inventors: Konishi, Shozaburo, Kano, Makoto, Yasuda, Yoshiteru, Mabuchi, Yutaka, Hamada, Takahiro, Takeshima, Shigeki, Tsushima, Kenji
• Primary Examiner(s): Hannon, Thomas R
• Application Number:
  US12/835,705
• Publication Number:
  US 20110028361A1
• Time in Patent Office: 637 Days
• Field of Search: 384/13, 384/42, 384/129, 384/297, 384/322, 384/907.1
• US Class Current: 384/13
• CPC Class Codes: C10M 163/00 Lubricating compositions characterised by the additive being a mixture of a compound of unknown or incompletely defined constitution and a non-macromolecular compound, each of these compounds being essential
• CPC Class Codes: C10M 2203/1006 used as base material
• CPC Class Codes: C10M 2205/0285 used as base material
• CPC Class Codes: C10M 2207/028 Overbased salts thereof
• CPC Class Codes: C10M 2207/289 containing free hydroxy groups
• CPC Class Codes: C10M 2215/042 containing hydroxy groups; Alkoxylated derivatives thereof
• CPC Class Codes: C10M 2215/28 Amides; Imides
• CPC Class Codes: C10M 2219/046 Overbasedsulfonic acid salts
• CPC Class Codes: C10M 2219/068 Thiocarbamate metal salts
• CPC Class Codes: C10M 2223/045 Metal containing thio derivatives
• CPC Class Codes: C10N 2010/04 Groups 2 or 12
• CPC Class Codes: C10N 2010/12 Groups 6 or 16
• CPC Class Codes: C10N 2040/04 Oil-bath; Gear-boxes; Automatic transmissions; Traction drives
• CPC Class Codes: C10N 2040/18 in connection with recordings on magnetic tape or disc
• CPC Class Codes: C10N 2040/25 Internal-combustion engines
• CPC Class Codes: F16C 2204/20 Alloys based on aluminium
• CPC Class Codes: F16C 2204/26 Alloys based on magnesium
• CPC Class Codes: F16C 2206/04 Diamond like carbon [DLC]
• CPC Class Codes: F16C 33/04 Brasses; Bushes; Linings
• CPC Class Codes: F16C 33/10 Construction relative to lubrication lubrication in general F16N
• CPC Class Codes: F16C 33/109 : Lubricant compositions or properties, e.g. viscosity
• CPC Class Codes: F16C 33/12 : Structural composition; Use of special materials or surface treatments, e.g. for rust-proofing

Abstract

A low-friction sliding mechanism includes first and second sliding members having respective sliding surfaces slidable relative to each other and a lubricant applied to the sliding surfaces of the first and second sliding members. At least the sliding surface of the first sliding member is made of a diamond-like carbon material, and at least the sliding surface of the second sliding member is made of either an aluminum-based alloy material, a magnesium-based alloy material or a diamond-like carbon material. The lubricant contains a base oil and at least one of an ashless fatty-ester friction modifier and an ashless aliphatic-amine friction modifier.

Claims

1. A low-friction sliding mechanism, comprising:

a first sliding member having a sliding surface, at least the sliding surface of the first sliding member comprising a diamond-like carbon material;

a second sliding member having a sliding surface slidable relative to the sliding surface of the first sliding member, the second sliding member being formed in one piece of diamond-like carbon material; and

a lubricant applied to the sliding surfaces of the first and second sliding members, the lubricant comprising at least one of an ashless fatty-ester friction modifier and an ashless aliphatic-amine friction modifier.

2. A low-friction sliding mechanism according to claim 1, wherein the diamond-like carbon material of the first sliding member is hydrogen-free amorphous carbon.

3. A low-friction sliding mechanism according to claim 1, wherein the aluminum-based alloy material of the second sliding member is a hypoeutectic or hypereutectic aluminum alloy containing 4 to 20% by mass silicon and 1.0 to 5.0% by mass copper.

4. A low-friction sliding mechanism according to claim 1, wherein the magnesium-based alloy material of the second sliding member comprises at least one alloy selected from the group consisting of magnesium-aluminum- zinc alloys, magnesium-aluminum-rare earth metal alloys, magnesium- aluminum-calcium alloys, magnesium-zinc-aluminum-calcium alloys, magnesium-aluminum-calcium-rare earth metal alloys, magnesium-aluminum- strontium alloys, magnesium-aluminum-silicon alloys, magnesium-rare earth metal-zinc alloys, magnesium-silver-rare earth metal alloys and magnesium-yttrium-rare earth metal alloys.

5. A low-friction sliding mechanism according to claim 1, wherein each of the sliding surfaces of the first and second sliding member has an arithmetic mean roughness of 0.1 μ

m or less.

6. A low-friction sliding mechanism according to claim 1, wherein the first sliding member comprises a base and a coating of the diamond-like carbon material applied to the base to define the sliding surface, the coating has a thickness of 0.3 to 2.0 μ

m and a micro Vickers hardness HV of 1000 to 3500 as measured by application of a 10 g load, the second sliding member is made of the aluminum-based alloy material, and the sliding surface of the second sliding member has a Brinell hardness HB of 80 to 130.

7. A low-friction sliding mechanism according to claim 1, wherein the first sliding member comprises a base and a coating of the diamond-like carbon material applied to the base to define the sliding surface, the coating has a thickness of 0.3 to 2.0 μ

m and a micro Vickers hardness HV of 1000 to 3500 as measured by application of a 10 g load, the second sliding member comprises an magnesium-based alloy material, and the sliding surface of the second sliding member has a Brinell hardness HB of 45 to 95.

8. An internal combustion engine comprising a low-friction sliding mechanism according to claim 1.

9. A low-friction sliding mechanism according to claim 1, wherein the fatty-ester friction modifier and the aliphatic-amine friction modifier comprise C6-C30 straight or branched hydrocarbon chains, respectively, and the lubricant comprises 0.05 to 3.0% by mass based on the total mass of the lubricant of the at least one of the fatty-ester friction modifier and the aliphatic-amine friction modifier.

10. A low-friction sliding mechanism according to claim 1, wherein the lubricant further comprises polybutenyl succinimide and/or a derivative thereof.

11. A low-friction sliding mechanism according to claim 10, wherein the lubricant comprises 0.1 to 15% by mass based on the total mass of the lubricant of the polybutenyl succinimide and/or the derivative.

12. A low-friction sliding mechanism according to claim 1, wherein the lubricant further comprises zinc dithiophosphate in an amount of 0.1% or less by mass in terms of an phosphorus element based on a total mass of the lubricant.

13. A low-friction sliding mechanism, comprising:

a first sliding member having a sliding surface, at least the sliding surface of the first sliding member comprising a diamond-like carbon material wherein the diamond-like carbon material of the first sliding member is hydrogen-free amorphous carbon;

a second sliding member having a sliding surface slidable relative to the sliding surface of the first sliding member, the second sliding member consisting essentially of a diamond-like carbon material; and

a lubricant applied to the sliding surfaces of the first and second sliding members, the lubricant comprising friction modifier.