SLIDING MEMBER AND SLIDING MACHINE

• US 20190323498A1
• Filed: 01/03/2019
• Published: 10/24/2019
• Est. Priority Date: 04/20/2018
• Status: Active Grant

• Current Assignee: Jtekt Corporation (Toyota Motor Corporation), Kabushiki Kaisha Toyota Chuo Kenkyusho (Toyota Motor Corporation)
• Original Assignee: Kabushiki Kaisha Toyota Chuo Kenkyusho (Toyota Motor Corporation)
• Inventors: OKUYAMA, Masaru, MORI, Hiroyuki, TOHYAMA, Mamoru, EMOTO, Noriyuki, YOSHIDA, Naohito
• Granted Patent: US 10,851,776 B2
• Time in Patent Office: Days
• CPC Class Codes: C10M 169/04 Mixtures of base-materials and additives
• CPC Class Codes: C10M 2201/04 Elements
• CPC Class Codes: C10M 2201/041 Carbon; Graphite; Carbon black
• CPC Class Codes: C10M 2227/066 derived from Mo or W
• CPC Class Codes: C10N 2020/06 Particles of special shape or size
• CPC Class Codes: C10N 2020/061 Coated particles
• CPC Class Codes: C10N 2030/06 Oiliness; Film-strength; Anti-wear; Resistance to extreme pressure
• CPC Class Codes: C10N 2040/00 Specified use or application for which the lubricating composition is intended
• CPC Class Codes: C10N 2040/045 for continuous variable transmission [CVT]
• CPC Class Codes: C10N 2040/44 Super vacuum or supercritical use
• CPC Class Codes: C10N 2050/025 in the form of films or sheets
• CPC Class Codes: F04C 2/344 with vanes reciprocating with respect to the inner member

Abstract

A sliding member has a sliding surface sliding under a wet condition in which a lubricant oil exists. The sliding surface is coated with a laminate film comprising an upper layer and a lower layer. The lower layer comprises hydrogen-free amorphous carbon (hydrogen-free DLC) and carbon particles dispersed on or in the hydrogen-free DLC. The hydrogen-free DLC has a hydrogen content of 5 atom % or less when the lower layer as a whole is 100 atom %. The upper layer comprises boron-containing amorphous carbon (B-DLC) and has protrusions on a surface side of the upper layer along the carbon particles of the lower layer. The B-DLC has a boron content of 1-40 atom % when the upper layer as a whole is 100 atom %. The protrusions have a particle diameter of 0.5-5 μm and exist with a density of 20 protrusions/100 μm² or more.

Claims

1. A sliding member having a sliding surface sliding under a wet condition in which a lubricant oil exists,

the sliding surface being coated with a laminate film comprising an upper layer and a lower layer,

the lower layer comprising hydrogen-free amorphous carbon (referred to as “

hydrogen-free DLC”

) and carbon particles dispersed on or in the hydrogen-free DLC and having a hydrogen content of 5 atom % or less when the lower layer as a whole is 100 atom %,

the upper layer comprising boron-containing amorphous carbon (referred to as “

B-DLC”

) and having protrusions on a surface side of the upper layer along the carbon particles of the lower layer, the B-DLC having a boron content of 1-40 atom % when the upper layer as a whole is 100 atom %,

the protrusions having a particle diameter of 0.5-5 μ

m and existing with a density of 20 protrusions/100 μ

m² or more.

2. The sliding member as recited in claim 1, wherein

the B-DLC has a thickness of 0.2-3 μ

m, and

the hydrogen-free DLC has a thickness of 0.5-5 μ

m.

3. The sliding member as recited in claim 1, wherein

the B-DLC has hardness of 15-35 GPa, and

the hydrogen-free DLC has hardness of 40-70 GPa.

4. A sliding machine comprising:

a pair of sliding members having sliding surfaces that can relatively move while facing each other; and

a lubricant oil interposed between the sliding surfaces facing each other,

at least one of the sliding members comprising the sliding member as recited in claim 1.

5. The sliding machine as recited in claim 4, wherein the sliding machine is an oil pump that pumps the lubricant oil under pressure.

6. The sliding machine as recited in claim 5, wherein

the pair of sliding members are a vane and a cam ring,

the oil pump is a vane pump, and

the vane has the sliding surface coated with the laminate film on a tip end side of the vane.

7. The sliding machine as recited in claim 6, wherein the cam ring comprises an iron-based sintered material.

8. The sliding machine as recited in claim 4, wherein the lubricant oil contains an oil-soluble molybdenum compound with a mass ratio of Mo to the lubricant oil as a whole of 200-1000 ppm, wherein the oil-soluble molybdenum compound has a chemical structure comprising a trinuclear of Mo.