Toyota Jidosha Kabushiki Kaisha

Kabushiki Kaisha Toyota Chuo Kenkyusho

Jtekt Corporation

Masaru Okuyama

Hiroyuki Mori

Mamoru Tohyama

Naoya Ikeda

Keiji Hayashi

Yoshio Fuwa

Kazuyuki Nakanishi

Hideo Tachikawa

Takatoshi Shinyoshi

Toshihide Ohmori

Naohito Yoshida

Munehisa Matsui

Noriyuki Emoto

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 &#x3bc;m and exist with a density of 20 protrusions/100 &#x3bc;mor more.

Sliding member and sliding machine

[Technical Problem] An object is to provide a sliding system which can achieve both the reduced friction and the enhanced wear resistance by means of a novel combination of a sliding film and a lubricant oil. [Solution to Problem] The sliding system of the present invention comprises: 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 surfaces comprises a coating surface of a crystalline chromium carbide film. The lubricant oil contains an oil-soluble molybdenum compound that has a chemical structure of a trinuclear of Mo. When the chromium carbide film as a whole is 100 at %, the chromium carbide film contains 40-75 at % of Cr. The chromium carbide film in contact with the lubricant oil containing a Mo-trinuclear appears to react with the Mo-trinuclear adsorbed during the sliding to generate a layered structural body (boundary film) similar to MoSon the surface, thereby developing a considerably low friction property.

Sliding system

A sliding machine includes: a pair of sliding members having sliding surfaces that oppose each other and are able to move relative to each other; and a lubricating oil which is able to be interposed between the opposed sliding surfaces, in which at least one of the sliding surfaces is covered with a chromium (Cr)-containing amorphous carbon film (chromium-coating DLC), and the lubricating oil contains an oil-soluble molybdenum compound having a chemical structure formed from a trinuclear material of molybdenum (Mo). Specifically, the chromium-coating DLC contains, when the entirety of the film is assumed to be 100 at. %, 1% to 49% of Cr, 0% to 30% of hydrogen (H), carbon (C) as a remainder, and impurities. The lubricating oil contains 5 ppm to 800 ppm of the oil-soluble molybdenum compound in terms of Mo mass ratio with respect to the entirety of the lubricating oil.

Sliding machine

[Technical Problem] An object is to provide a sliding system which can drastically reduce the friction coefficient on a sliding portion by means of a novel combination of a chromium nitride film and a lubricant oil. [Solution to Problem] The sliding system according to the present invention includes: a pair of sliding members having sliding surfaces that can relatively move while facing each other; and a lubricant oil that can be interposed between the sliding surfaces facing each other. At least one of the sliding surfaces is formed as a coating surface of a chromium nitride film, and the lubricant oil contains an oil-soluble molybdenum compound that has a chemical structure of a trinuclear of Mo. When the chromium nitride film as a whole is 100 at % (referred simply to as '%'), the chromium nitride film contains 40-65% of Cr and 35-55% of N, and the chromium nitride film has a relative surface area of 15-60% wherein the relative surface area is a surface area ratio of (111) plane to (200) plane obtained when analyzed using X-ray diffraction. The lubricant oil preferably contains 5-800 ppm of the oil-soluble molybdenum compound in a content mass of Mo to the lubricant oil as a whole.

The sliding member according to the present invention includes: a base material; and a sliding film that covers a surface of the base material and constitutes a sliding surface, and is used under a wet condition where lubricant oil exists. The sliding film according to the present invention is a laminated film that includes: an underlying layer formed on the surface of the base material; and an outermost layer formed at least on a part of the underlying layer. This outermost layer is characterized by including specific boron-containing amorphous carbon (specific B-DLC) that contains 4-50% B and 5-50% H when the outermost layer as a whole is 100 at %. This specific B-DLC itself wears away during the sliding to smooth the sliding surface, and an excellent low friction property is exhibited. The underlying layer of the specific B-DLC contributes to improvement in the wear resistance property of the sliding film.

Under wet sliding conditions using drivetrain system lubricating oils, a high frictional sliding member exhibiting a high friction coefficient, a favorable &#x3bc;&#x2212;v characteristic stably, excellent wear resistance, and low mating-member aggressiveness is provided. The present invention is a wet sliding member comprising: a substrate composed of metal, ceramics, or resin; and an amorphous hard carbon film formed integrally on a surface of the substrate, having a surface, at least a part of which is turned into a sliding surface for sliding under wet conditions, and containing at least either one of Si and N in an amount of from 1 to 50 atomic %.

Growing community of inventors

Nagakute, Japan

Masaru Okuyama