Low-friction sliding member in transmission, and transmission oil therefor

• US 7,650,976 B2
• Filed: 11/28/2007
• Issued: 01/26/2010
• Est. Priority Date: 08/22/2003
• Status: Active Grant

• Current Assignee: Nissan Motor Co., Ltd.
• Original Assignee: Nissan Motor Co., Ltd.
• Inventors: Nakamura, Kiyotaka, Kano, Makoto, Ishikawa, Takao, Ueno, Takafumi
• Primary Examiner(s): Bonck; Rodney H
• Application Number:
  US11/946,407
• Publication Number:
  US 20080236984A1
• Time in Patent Office: 790 Days
• Field of Search: None
• US Class Current: 192/107.00M
• CPC Class Codes: C10M 129/00 Lubricating compositions characterised by the additive being an organic non-macromolecular compound containing oxygen
• CPC Class Codes: C10M 133/06 having amino groups bound to acyclic or cycloaliphatic carbon atoms
• CPC Class Codes: C10M 2205/0285 used as base material
• CPC Class Codes: C10M 2207/021 having hydroxy groups bound to acyclic or cycloaliphatic carbon atoms
• CPC Class Codes: C10M 2207/022 containing at least two hydroxy groups
• CPC Class Codes: C10M 2207/04 Ethers; Acetals; Ortho-esters; Ortho-carbonates
• CPC Class Codes: C10M 2207/044 Cyclic ethers having four or more ring atoms, e.g. furans, dioxolanes
• CPC Class Codes: C10M 2207/122 monocarboxylic
• CPC Class Codes: C10M 2207/123 polycarboxylic
• CPC Class Codes: C10M 2207/126 monocarboxylic
• CPC Class Codes: C10M 2207/127 polycarboxylic
• CPC Class Codes: C10M 2207/141 monocarboxylic
• CPC Class Codes: C10M 2207/142 polycarboxylic
• CPC Class Codes: C10M 2207/281 of (cyclo)aliphatic monocarboxylic acids
• CPC Class Codes: C10M 2207/282 of (cyclo)aliphatic oolycarboxylic acids
• CPC Class Codes: C10M 2207/285 of aromatic polycarboxylic acids
• CPC Class Codes: C10M 2207/289 containing free hydroxy groups
• CPC Class Codes: C10M 2209/108 etherified
• CPC Class Codes: C10M 2215/04 having amino groups bound to acyclic or cycloaliphatic carbon atoms
• CPC Class Codes: C10M 2215/042 containing hydroxy groups; Alkoxylated derivatives thereof
• CPC Class Codes: C10M 2215/224 : Imidazoles
• CPC Class Codes: C10M 2215/28 : Amides; Imides
• CPC Class Codes: C10N 2030/06 : Oiliness; Film-strength; Anti-wear; Resistance to extreme pressure
• CPC Class Codes: C10N 2040/042 : for automatic transmissions
• CPC Class Codes: C10N 2040/045 : for continuous variable transmission [CVT]
• CPC Class Codes: C10N 2060/14 : by boron or a compound containing boron
• CPC Class Codes: F16C 33/16 : Sliding surface consisting mainly of graphite
• CPC Class Codes: F16H 57/041 : Coatings or solid lubricants, e.g. antiseize layers or pastes
• CPC Class Codes: Y10T 428/30 : Self-sustaining carbon mass or layer with impregnant or other layer

Abstract

A low-friction sliding member in a transmission is at least one of sliding members which are in slidable contact with each other in presence of a transmission oil composition. The low-friction sliding member includes a base material having a sliding section. A hard carbon thin film is coated at a sliding surface of the sliding section of the base material. The hard carbon thin film contains hydrogen in an amount not more than 20 atomic %. The transmission oil composition contains at least one of organic oxygen-containing compound and aliphatic amine compound.

Claims

1. A low-friction sliding member in a transmission, the sliding member being at least one of a plurality of sliding members which are in slidable contact with each other in the presence of a transmission oil composition, the low-friction sliding member comprising:

a base material having a sliding section; and

a hard carbon thin film coated on a sliding surface of the sliding section of the base material,

wherein the transmission oil composition comprises at least one of an organic oxygen-containing compound and aliphatic amine compound,

wherein the transmission comprises a continuously variable transmission, and

wherein the hard carbon thin film contains hydrogen in an amount not more than 0.5 atomic %.

2. A low-friction sliding member as claimed in claim 1, wherein the sliding section of the base material has a surface roughness (Ra) not larger than 0.1 μ

in a condition before the base material is coated with the hard carbon thin film.

3. A low-friction sliding member as claimed in claim 1, wherein the hard carbon thin film has a surface hardness (Hv) ranging from 1000 to 3500 in micro Vickers hardness as measured under application of a 10 g load, and a thickness ranging from 0.3 to 2.0 μ

m.

4. A low-friction sliding member as claimed in claim 1, wherein the hard carbon thin film comprises amorphous DLC and is formed by a physical vapor deposition process.

5. A low-friction sliding member in a transmission, the sliding member being at least one of a plurality of sliding members which are in slidable contact with each other in the presence of a transmission oil composition, the low-friction sliding member comprising:

a base material having a sliding section; and

a hard carbon thin film coated at a sliding surface of the sliding section of the base material,

wherein the transmission oil composition comprises at least one of an organic oxygen-containing compound and aliphatic amine compound,

wherein the transmission comprises an automatic transmission, and

wherein the hard carbon thin film contains hydrogen in an amount not more than 0.5 atomic %.

6. A low-friction sliding member as claimed in claim 5, wherein the sliding section of the base material has a surface roughness (Ra) not larger than 0.1μ

in a condition before the base material is coated with the hard carbon thin film.

7. A low-friction sliding member as claimed in claim 5, wherein the hard carbon thin film has a surface hardness (Hv) ranging from 1000 to 3500 in micro Vickers hardness as measured under application of a 10 g load, and a thickness ranging from 0.3 to 2.0 μ

m.

8. A low-friction sliding member as claimed in claim 5, wherein the hard carbon thin film comprises amorphous DLC and is formed by a physical vapor deposition process.