Engine piston-pin sliding structure

• US 7,228,786 B2
• Filed: 05/13/2004
• Issued: 06/12/2007
• Est. Priority Date: 06/06/2003
• Status: Expired due to Fees

• Current Assignee: Nissan Motor Co., Ltd.
• Original Assignee: Nissan Motor Co., Ltd.
• Inventors: Kano, Makoto, Hamada, Takahiro, Mabuchi, Yutaka, Miyake, Hidenori
• Primary Examiner(s): LESLIE, MICHAEL S
• Application Number:
  US10/844,395
• Publication Number:
  US 20040261614A1
• Time in Patent Office: 1,125 Days
• Field of Search: 921/55, 921/57, 921/58, 921/87, 922/16, 922/55, 745/95
• US Class Current: 92/155
• CPC Class Codes: C10M 2207/281 of (cyclo)aliphatic monocarboxylic acids
• CPC Class Codes: C10M 2207/283 of polyhydroxy compounds
• CPC Class Codes: C10M 2207/289 containing free hydroxy groups
• 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 2215/28 Amides; Imides
• CPC Class Codes: C10M 2223/045 Metal containing thio derivatives
• CPC Class Codes: C10N 2030/06 Oiliness; Film-strength; Anti-wear; Resistance to extreme pressure
• CPC Class Codes: C23C 14/0605 Carbon
• CPC Class Codes: F16J 1/16 with gudgeon-pin; Gudgeon-pins

Abstract

An engine piston-pin sliding structure includes a piston pin slidably engaged into a pin boss of an engine piston and having a base and a hard carbon coating formed on the base so as to define a sliding surface slidable over a bearing surface of the pin boss and a lubricant interposed between the sliding surface of the piston pin and the bearing surface of the pin boss. The hard carbon coating contains 25 atomic % or less of hydrogen, and the lubricant contains at least one of an ashless fatty-ester friction modifier and an ashless aliphatic-amine friction modifier.

Claims

1. An engine piston-pin sliding structure, comprising:

a piston pin slidably engaged into a pin boss of an engine piston, the piston pin having a pin base and a hard carbon coating formed by physical vapor deposition on the pin base so as to define a sliding surface slidable over a bearing surface of the pin boss, the hard carbon coating containing 25 atomic % or less of hydrogen; and

a lubricant interposed between the sliding surface of the piston pin and the bearing surface of the pin boss, the lubricant containing at least one of an ashless fatty-ester friction modifier and an ashless aliphatic-amine friction modifier.

2. An engine piston-pin sliding structure according to claim 1, wherein the hard carbon coating contains 5 atomic % or less of hydrogen.

3. An engine piston-pin sliding structure according to claim 2, wherein the hard carbon coating contains 0.5 atomic % or less of hydrogen.

4. An engine piston-pin sliding structure according to claim 1, wherein said at least one of the ashless fatty-ester friction modifier and the ashless aliphatic-amine friction modifier has a C₆–

C₃₀ hydrocarbon group and is contained in an amount of 0.05 to 3.0% by mass based on the total mass of the lubricant.

5. An engine piston-pin sliding structure according to claim 1, wherein the lubricant further contains polybutenyl succinimide and/or a derivative thereof.

6. An engine piston-pin sliding structure according to claim 5, wherein the polybutenyl succinimide and/or the derivative thereof is contained in an amount of 0.1 to 15% based on the total mass of the lubricant.

7. An engine piston-pin sliding structure according to claim 1, wherein the lubricant further contains 0.1% or less of zinc dithiophosphate in terms of phosphorus based on the total mass of the lubricant.

8. An engine piston-pin sliding structure according to claim 1, wherein the hard carbon coating is a diamond-like carbon coating formed by arc ion plating.

9. An engine piston-pin sliding structure according to claim 1, wherein the pin base has a surface roughness Ra of 0.03 μ

m or lower.

10. A piston pin to be slidably engaged into a pin boss of an engine piston with a lubricant interposed between the piston pin and pin boss, the lubricant containing at least one of an ashless fatty-acid friction modifier and an ashless aliphatic-amine friction modifier, the piston pin comprising:

a pin base; and

a hard carbon coating formed by physical vapor deposition on the pin base so as to define a sliding surface slidable over a bearing surface of the pin boss via the lubricant, the hard carbon coating having 25 atomic % or less of hydrogen.

11. A piston pin according to claim 10, wherein the hard carbon coating has 5 atomic % or less of hydrogen.

12. A piston pin according to claim 11, wherein the hard carbon coating has 0.5 atomic % or less of hydrogen.

13. A piston pin according to claim 10, wherein the hard carbon coating is a diamond-like carbon coating formed by arc ion plating.

14. A piston pin according to claim 10, wherein the pin base has a surface roughness Ra of 0.03 μ

m or lower.