Sliding structure for automotive engine

• US 7,255,083 B2
• Filed: 05/02/2005
• Issued: 08/14/2007
• Est. Priority Date: 10/16/2002
• Status: Expired due to Fees

• Current Assignee: Nissan Motor Co., Ltd.
• Original Assignee: Nissan Motor Co., Ltd.
• Inventors: Kano, Makoto, Hamada, Takahiro, Okamoto, Yusuke, Mabuchi, Yutaka, Yasuda, Yoshiteru
• Primary Examiner(s): MCMAHON, MARGUERITE J
• Application Number:
  US11/118,360
• Publication Number:
  US 20050188942A1
• Time in Patent Office: 834 Days
• Field of Search: 1231931-1936, 427/450, 427/540, 427/250, 428/698, 428/217, 921/58
• US Class Current: 123/193.4
• CPC Class Codes: C23C 14/0605 Carbon
• CPC Class Codes: F01L 1/022 Chain drive
• CPC Class Codes: F01L 1/047 Camshafts
• CPC Class Codes: F01L 1/16 Silencing impact; Reducing wear
• CPC Class Codes: F01L 1/3442 using hydraulic chambers with variable volume to transmit the rotating force
• CPC Class Codes: F01L 2001/0476 Camshaft bearings
• CPC Class Codes: F01L 2301/00 Using particular materials
• CPC Class Codes: F01L 2820/01 Absolute values
• CPC Class Codes: F01L 2820/02 Formulas
• CPC Class Codes: F16C 33/16 Sliding surface consisting mainly of graphite
• CPC Class Codes: F16G 13/06 with links connected by parallel driving-pins with or without rollers so called open links if the parallel coupling pins have only a joining function - so called closed links - F16G13/02
• CPC Class Codes: F16J 1/02 Bearing surfaces
• CPC Class Codes: F16J 1/16 with gudgeon-pin; Gudgeon-pins
• CPC Class Codes: F16J 9/26 characterised by the use of particular materials

Abstract

A sliding structure for an automotive engine includes a sliding member with a sliding portion and a lubricant applied to the sliding portion so that the sliding portion can make sliding contact with a counterpart member via the lubricant. The sliding member is either of a piston ring, a piston pin, a cam lobe, a cam journal, a plain bearing, a rotary vane and a timing chain. The sliding portion has a base made of a steel or aluminum material and a hard carbon film formed on the base to coat the sliding portion. The hard carbon film has a thickness of 0.3 to 2.0 μm, a Knoop hardness of 1500 to 4500 kg/mm², a surface roughness Ry (μm) satisfying the following equation: Ry<{(0.75−Hk/8000)×h+0.07/0.8}, where h is the thickness (μm) of the film; and Hk is the Knoop hardness (kg/mm²) of the film.

Claims

1. A sliding structure comprising:

a sliding member which comprises a first sliding surface; and

a lubricant applied to the first sliding surface so that the first sliding surface can make sliding contact with a second sliding surface on a counterpart member via the lubricant,

wherein at least one of the first sliding surface and the second sliding surface comprises a hard carbon film, and the hard carbon film has a thickness of 0.3 to 2.0 μ

m, a Knoop hardness of 1500 to 4500 kg/mm², a surface roughness Ry (μ

m) satisfying the following equation;

Ry<

{(0.75−

Hk/8000)×

h+0.07/0.8}

where h is the thickness (μ

m) of the hard carbon film; and

Hk is the Knoop hardness (kg/mm²) of the hard carbon film.

2. A sliding structure according to claim 1, wherein the hard carbon film is a diamond-like carbon film formed by arc ion plating.

3. A sliding structure according to claim 1, wherein the base with a surface roughness Ra of 0.03 μ

m or smaller.

4. A sliding structure according to claim 1, wherein the sliding surface coated with the hard carbon film has a convexity of which maximum height is 0.3 μ

m or smaller.

5. A sliding structure according to claim 1, wherein the lubricant comprises a base oil having a kinematic viscosity of 2 to 8 m²/s at 100°

C. and a viscosity index of 80 or higher.

6. A sliding structure according to claim 1, wherein the lubricant comprises at least one additive selected from the group consisting of an anti-wear agent, a detergent dispersant, a viscosity index improver, a friction modifier, an anti-forming agent, a pour-point depressant, a rust inhibitor and an antioxidant.

7. A sliding structure according to claim 1, wherein the base comprises a steel material or an aluminum material.

8. An automotive engine comprising a sliding structure according to claim 1.

9. A piston ring, a piston pin, a cam lobe, a cam journal, a plain bearing, a rotary vane or a timing chain comprising a sliding structure according to claim 1.