JP2008241032A - Piston ring and its manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a piston ring excellent in Al-agglutination-resistance and wear-resistance relative to upper and lower surfaces of a piston ring groove, and to provide a piston ring excellent in an initial concordance property, wear-resistance and scuff-resistance relative to a cylinder liner of an outer peripheral slide surface of the piston ring. <P>SOLUTION: In the piston ring, a hard carbon film 2 is formed on at least upper surface 8 and a lower surface 9. In the hard carbon film 2, an oxygen content is 1 atom% to 10 atom%, a hydrogen content is 10 atom% to 40 atom%, and a silicon content is 0.1 atom% to 20 atom%. In the first piston ring 10, a structure form of the hard carbon film 2 is columnar structure 2x, and the structure form of the hard carbon film 2 formed on the outer peripheral slide surface 6 becomes a fine structure 2y different from the columnar structure 2x. Further, in the second piston ring in which the hard carbon film is formed on the outer peripheral slide surface, a surface form of the formed hard carbon film has a granular form, and an average particle diameter of the granular form is 700 nm or less. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a piston ring and a method for manufacturing the same, and more specifically, is excellent in initial conformability with the upper and lower surfaces of the piston ring groove provided in the piston and wear resistance, and aluminum adhesion (hereinafter referred to as Al adhesion). The present invention relates to a piston ring in which a hard carbon film that can be suppressed is formed, a piston ring in which a hard carbon film excellent in initial conformability and wear resistance with a cylinder liner is formed, and a method for manufacturing the same.

  In recent years, with the reduction in weight and output of internal combustion engines, piston rings are also required to be further improved in wear resistance and scuff resistance. Under these circumstances, Cr plating films, nitride layers, and the like are formed on the outer peripheral sliding surface and upper and lower surfaces of the piston ring to improve wear resistance and scuff resistance. In recent years, the above requirements have been met by adopting hard films such as CrN (chromium nitride) and TiN (titanium nitride) produced by PVD (physical vapor deposition).

  When the above-mentioned Cr plating film, nitride layer, or hard film made by the PVD method is formed on the upper and lower surfaces of the piston ring, the upper and lower surfaces of the piston ring groove, in particular, where the upper and lower surfaces of the piston ring are made of an Al alloy. As a result, there is a risk of causing an Al adhesion phenomenon and increasing wear in the piston ring groove. For such problems, it has been studied to suppress the Al adhesion phenomenon by forming hard carbon films (sometimes referred to as diamond-like carbon films; the same shall apply hereinafter) on the upper and lower surfaces of the piston ring (for example, , See Patent Documents 1 and 2).

In addition, when the Cr plating film, nitride layer, or hard film produced by the PVD method described above is formed on the outer peripheral sliding surface of the piston ring, the wear resistance to the cylinder liner can be further improved, or the initial familiarity. In order to improve performance, it has been studied to form a hard carbon film similar to the above on the outer peripheral sliding surface of the piston ring (see, for example, Patent Documents 3 and 4).
JP 2000-120869 A JP 2006-283970 A JP 2001-316819 A Japanese Patent Laid-Open No. 2007-232026

  However, the upper and lower surfaces of the piston ring are struck by the upper and lower surfaces in the piston ring groove every time the piston moves up and down. As a result, Al adhesion occurs on the upper and lower surfaces of the piston ring, particularly the lower surface side, and wear occurs. In the conventional piston ring described above, it cannot be said that the Al adhesion resistance and wear resistance of the hard carbon films formed on the upper and lower surfaces have been sufficiently studied. there were.

  Further, the outer peripheral sliding surface of the piston ring is required to have excellent initial conformability with the cylinder liner, wear resistance, and scuff resistance, but demands for these characteristics are increasing day by day. Therefore, further research and development to meet these requirements is desired.

  The present invention has been made to solve these problems, and a first object of the present invention is to provide a piston ring excellent in Al adhesion resistance and wear resistance on the upper and lower surfaces of the piston ring groove. There is to do. A second object of the present invention is to provide a piston ring that is excellent in initial conformability, wear resistance, and scuff resistance to the cylinder liner of the outer peripheral sliding surface of the piston ring. A third object of the present invention is to provide a method for manufacturing such a piston ring.

  A piston ring according to a first aspect of the present invention that achieves the first object is a piston ring in which a hard carbon film is formed on at least an upper surface and a lower surface, and the hard carbon film has an oxygen content of 1. The atomic content is 10 atomic percent or more and 10 atomic percent or less; the hydrogen content is 10 atomic percent or more and 40 atomic percent or less; the silicon content is 0.1 atomic percent or more and 20 atomic percent or less; It is characterized by a columnar structure.

  According to the present invention, since the hard carbon film having the above component composition and structure is formed on at least the upper surface and the lower surface, the initial conformability is good and the Al adhesion resistance and the wear resistance are excellent. Can do. In particular, the structure of the hard carbon film is a columnar structure, and its surface has irregularities, so that it has a function as an oil reservoir. As a result, the opponent aggression can be reduced, and a particularly excellent suppression effect can be obtained for Al adhesion that is likely to occur between the piston ring groove. The piston ring of the present invention is not simply formed with a hard carbon film, but is superior in Al adhesion resistance and wear resistance compared to conventional ones by specifying its component composition and structure morphology. .

  In the piston ring according to the first aspect of the present invention, the hard carbon film is further continuously formed on the outer peripheral sliding surface of the piston ring, and the structure of the hard carbon film formed on the outer peripheral sliding surface. Is preferably a dense structure.

  According to the present invention, the structure of the hard carbon film on the upper surface and the lower surface is a columnar structure, whereas the structure of the hard carbon film formed on the outer peripheral sliding surface is a dense structure. On the other hand, a film having excellent wear resistance can be formed.

  In the piston ring according to the first aspect of the present invention, the surface roughness of the hard carbon film composed of the columnar structure is preferably 1.5 μm or more in terms of a ten-point average roughness Rz based on JIS B0601 (1994). .

  According to the present invention, since the surface roughness of the hard carbon film having a columnar structure is as described above, the uneven surface of the hard carbon film acts as an oil reservoir. As a result, the opponent aggression can be reduced, and a particularly excellent suppression effect can be achieved with respect to the Al adhesion that is likely to occur between the piston ring groove.

  The piston ring according to the second aspect of the present invention for achieving the second object is a piston ring in which a hard carbon film is formed on at least an outer peripheral sliding surface, and the hard carbon film has an oxygen content. 1 atom% or more and 10 atom% or less, hydrogen content is 10 atom% or more and 40 atom% or less, silicon content is 0.1 atom% or more and 20 atom% or less, and is formed on the outer peripheral sliding surface. The hard carbon film is characterized in that its surface form has a granular form, and the granular form has an average particle diameter of 700 nm or less.

  According to this invention, since the hard carbon film having the above component composition and granular form is formed at least on the outer peripheral sliding surface, the initial conformability to the cylinder liner is good, and the wear resistance and scuff resistance are also excellent. It can be. In particular, since the surface has fine irregularities due to a very large number of fine particles, it is excellent in initial conformability with the cylinder liner which is the counterpart material. The piston ring of the present invention is not simply formed of a hard carbon film, but by specifying its component composition and surface form, the piston ring is particularly excellent in initial conformability and wear resistance as compared with the conventional one.

  The piston ring which concerns on the 2nd viewpoint of this invention WHEREIN: It is preferable that the height of the grain of the said granular form is 70 nm or less.

  In the piston ring according to the second aspect of the present invention, the hard carbon film formed on the outer peripheral sliding surface has an initial wear height Rpk based on JIS B 0601 (2001) of 0.01 μm or more and 0.10 μm or less. It is preferable that

  According to the present invention, since the initial wear height Rpk is in the above-mentioned range, the surface has fine irregularities, so that the initial conformability with the cylinder liner as the counterpart material is excellent.

  In the piston ring according to the first and second aspects of the present invention, the outer peripheral sliding surface may be any one selected from a sputtering film, an ion plating film, a plating film, and a nitride layer as a surface film or the hard film It is preferably formed as a carbon film base film or base layer.

  According to this invention, at least the outer peripheral sliding surface of the piston ring is made of any one selected from a hard and tough sputtering film, an ion plating film, a plating film, and a nitride layer as a surface film or a hard carbon film. Since it is formed as a base film or base layer, for example, even if a hard carbon film formed on the outer peripheral sliding surface is worn, the wear resistance of the outer peripheral sliding surface can be maintained.

  As a preferred embodiment of the piston ring according to the first and second aspects of the present invention, an adhesion film containing at least Cr or Ti is provided between the hard carbon film and the piston ring base material from the base material side. A configuration in which the SiC film is formed in that order can be given.

  The piston ring manufacturing method of the present invention that achieves the third object is a method of manufacturing a piston ring in which a hard carbon film is formed by plasma CVD on at least one of the outer peripheral sliding surface and the upper and lower surfaces of the piston ring. The upper surface and the lower surface of the piston ring are arranged so as to be parallel to the ion flow from the plasma generation source, and the outer peripheral sliding surface is a surface perpendicular to the ion flow from the plasma generation source. And a hard carbon film having an oxygen content of 1 atomic% to 10 atomic%, a hydrogen content of 10 atomic% to 40 atomic%, and a silicon content of 0.1 atomic% to 20 atoms. It is characterized in that the film is formed so as to be not more than%.

  In the piston ring manufacturing method of the present invention, the structure of the hard carbon film formed on the upper surface and the lower surface is a columnar structure, and / or the structure of the hard carbon film formed on the outer peripheral sliding surface is a dense structure. And a surface form turns into a granular form. At this time, it is preferable that the granular form is prepared so that the average particle diameter is 700 nm or less and the height of the grains is 70 nm or less.

  According to the piston ring according to the first aspect of the present invention, initial conformability with the upper and lower surfaces of the piston ring groove is good, and Al adhesion resistance and wear resistance can be excellent. In particular, since the structure of the hard carbon film is a columnar structure and the surface has irregularities, it has a function as an oil reservoir, so that the opponent aggression can be reduced and Al adhesion easily occurs between the piston ring groove In particular, it has an excellent suppression effect. Further, the piston ring according to the second aspect of the present invention has good initial conformability to the cylinder liner, and can be excellent in wear resistance and scuff resistance. In particular, since the surface has fine irregularities due to a very large number of fine particles, it is excellent in initial conformability with the cylinder liner which is the counterpart material.

  Such a piston ring according to the present invention is not simply formed of a hard carbon film, but by specifying the component composition and the structure form or surface form thereof, compared to the conventional one, Al adhesion resistance and wear resistance are reduced. Or the initial conformability and wear resistance are excellent. The piston ring of the present invention can be sufficiently used for a high-power, high-temperature, high-load engine that is expected to be developed in the future.

  The method for manufacturing a piston ring according to the present invention can stably manufacture the piston ring according to the first aspect and the second aspect according to the second aspect with the above-described effects, with high controllability. A high-quality piston ring can be provided.

  Hereinafter, a piston ring and a manufacturing method thereof according to the present invention will be described with reference to the drawings.

(piston ring)
The present invention can be broadly divided into a piston ring according to the first aspect in which the hard carbon film is mainly formed on the upper and lower surfaces and a piston ring according to the second aspect in which the hard carbon film is mainly formed on the outer peripheral sliding surface. . Each will be described below, but common portions will be omitted as appropriate.

  1-3 is typical sectional drawing which shows the various examples of the piston ring which concerns on the 1st viewpoint of this invention. Piston rings 10, 11, 12 (10A,..., 10H, 11A,..., 11G, 12A,..., 12G according to the first aspect of the present invention are hereinafter referred to as “first piston ring 10”. 1), the hard carbon film 2 is formed on at least the upper surface 8 and the lower surface 9 on the base material 1, as shown in FIGS. The present invention is characterized in that the oxygen content is 1 atomic% to 10 atomic%, the hydrogen content is 10 atomic% to 40 atomic%, and the silicon content is 0.1 atomic%. The hard carbon film 2 that is 20 atomic% or less and whose structure is a columnar structure is formed on the upper surface 8 and the lower surface 9. The first piston ring 10 of the present invention having such a structure exhibits excellent initial conformability and wear resistance based on the action of the hard carbon film 2 having the above component composition and structure, and excellent Al adhesion resistance. Showing sex. 1 to 3 and 10, reference numeral 2x indicates a columnar structure, and reference numeral 2y indicates a dense structure. When these are collectively referred to in the text, they are referred to as "hard carbon film 2". .

  4 to 6 are schematic cross-sectional views showing various examples of piston rings according to the second aspect of the present invention. Piston rings 13, 14, 15 (13A, ..., 13F, 14A, ..., 14F, 15A, ..., 15F according to the second aspect of the present invention. 4), the hard carbon film 2 is formed on at least the outer peripheral sliding surface 6 on the base material 1. As shown in FIG. The present invention is characterized in that the oxygen content is 1 atomic% to 10 atomic%, the hydrogen content is 10 atomic% to 40 atomic%, and the silicon content is 0.1 atomic%. The hard carbon film 2 having an average particle diameter of 700 nm or less is formed on the outer peripheral sliding surface 6, which is 20 atomic% or less and the outermost sliding surface has a granular form. The second piston ring 13 of the present invention having such a configuration exhibits excellent initial conformability and wear resistance based on the above-described component composition and the action of the hard carbon film 2 having a granular form. 4 to 6 and 10, as in the first piston ring 10, reference numeral 2x indicates a columnar structure, and reference numeral 2y indicates a dense structure. “Hard carbon film 2”.

  The first and second piston rings 10 and 13 of the present invention are mounted in piston ring grooves formed in the piston, and slide on the inner peripheral surface of the cylinder liner by the vertical movement of the piston (same as reciprocal movement). Further, the sliding member moves up and down while being hit by the upper and lower surfaces in the piston ring groove. The first and second piston rings 10 and 13 of the present invention may be a top ring, a second ring, an oil ring, or all of them. The first and second piston rings 10 and 13 of the present invention are preferably used as piston rings attached to pistons made of aluminum alloy, and for cylinder liners made of cast iron, boron cast iron, cast steel, aluminum alloy or the like. It is preferably used as a piston ring, and can achieve excellent initial conformability, wear resistance, and Al adhesion resistance, which are the first object of the present invention, and is a second object, which is excellent. Initial conformability and wear resistance can be achieved.

  The base material 1 of the first and second piston rings 10 and 13 is not particularly limited as long as it is made of a conventionally used material. Therefore, the present invention can be applied to the base material 1 made of any material, and for example, a stainless steel material, a casting material, a cast steel material, a steel material and the like that are preferably used conventionally can be applied as the base material 1 for the piston ring, In addition, a material obtained by nitriding each base material can be applied.

  In the first piston ring 10, the hard carbon film 2 is formed on at least the upper surface 8 and the lower surface 9 on the base material 1, and exhibits excellent initial conformability, wear resistance, and Al adhesion resistance, and the piston ring. It is a film that can further improve the sliding characteristics with respect to the piston ring groove. The second piston ring 13 is formed on at least the outer peripheral sliding surface 6 on the base material 1 and has excellent initial conformability and wear resistance. This is a film that can further improve the sliding characteristics of the piston ring with respect to the cylinder liner. The hard carbon film 2 has an oxygen content of 1 atomic% to 10 atomic%, a hydrogen content of 10 atomic% to 40 atomic%, and a silicon content of 0.1 atomic% to 20 atomic%. The first piston ring 10 has the following component composition, and the tissue form is a columnar structure 2x, and the second piston ring 13 is a dense structure 2y. In addition, in this application, the component composition in the hard carbon film 2 can be quantified using a backscattering measurement apparatus, and a structure | tissue form is observed using a metal microscope or an X-ray microanalyzer (EPMA). Can do.

  As described above, the oxygen content is 1 atom% or more and 10 atom% or less, preferably 2 atom% or more and 7 atom% or less.

  In the first piston ring 10, when the hard carbon film 2 contains oxygen within the above range, the reaction component in the hard carbon film 2 easily reacts with oxygen in the atmosphere to form a compound. Since the compound is excellent in conformity (familiarity) with the upper and lower surfaces of the piston ring groove, which is the sliding surface of the counterpart material, there is an effect of exhibiting “initial conformability” that reduces the coefficient of friction particularly in the early stage of sliding. On the other hand, when the oxygen content is less than 1 atomic%, the obtained hard carbon film 2 hardly reacts with oxygen in the atmosphere, and a compound having excellent initial conformability is not generated, so that the wear amount increases and the wear resistance is poor. Tend. On the other hand, if the oxygen content exceeds 10 atomic%, “chips” tend to occur during sliding. The upper and lower surfaces of the piston ring groove are surfaces of a groove formed in the piston to which the first piston ring 10 of the present invention is attached, and the upper surface 8 and the lower surface 9 of the first piston ring 10 face each other. It is the surface to do. In particular, the first piston ring 10 of the present invention exhibits excellent Al adhesion resistance with respect to a piston ring groove formed of aluminum or an alloy thereof.

  On the other hand, in the second piston ring 13, similarly to the first piston ring 10, the reaction component in the hard carbon film 2 reacts with oxygen in the atmosphere by causing the hard carbon film 2 to contain oxygen within the above range. The compound is formed easily, but the compound is excellent in the compatibility (familiarity) with the cylinder liner which is the sliding surface of the mating material. There is an effect of playing. On the other hand, when the oxygen content is less than 1 atomic%, the obtained hard carbon film 2 hardly reacts with oxygen in the atmosphere, and a compound having excellent initial conformability is not generated, so that the wear amount increases and the wear resistance is poor. Tend. On the other hand, if the oxygen content exceeds 10 atomic%, “chips” tend to occur during sliding.

  As described above, the hydrogen content is 10 atom% or more and 40 atom% or less, preferably 20 atom% or more and 38 atom% or less.

  In the first and second piston rings 10 and 13, if the hydrogen content is less than 10 atomic%, the internal stress of the film becomes high, and “chip” may occur during sliding. On the other hand, if the hydrogen content exceeds 40 atomic%, the hardness of the film decreases and the film tends to wear.

  As described above, the silicon content is 0.1 atomic% or more and 20 atomic% or less, and preferably 2 atomic% or more and 10 atomic% or less.

  If the silicon content is less than 0.1 atomic%, the toughness is insufficient and “chips” may occur during sliding. On the other hand, when the silicon content exceeds 20 atomic%, it becomes easy to adhere to the upper and lower surfaces of the piston ring groove formed of aluminum or an alloy thereof.

  Of the components constituting the hard carbon film 2, the main component other than the above-mentioned oxygen, hydrogen, and silicon is carbon, and the carbon content is generally based on the total content of the above-mentioned components. It is in the range of 50 atomic% to 90 atomic%.

  In the first and second piston rings 10 and 13, the hardness of the hard carbon film 2 having the above component composition is adjusted to a Vickers hardness of 500 Hv (0.05) or more and 3000 Hv (0.05) or less by adjusting the content thereof. It can be controlled in a range. Further, the hard carbon film 2 has a laminated structure of two or more layers, and the hard carbon film 2 on the outermost surface thereof has a Vickers hardness of 500 Hv (0.05) or more and 1000 Hv (0.05) or less, thereby further improving initial conformability. Can be improved. If the Vickers hardness is less than 500 Hv (0.05), the wear resistance required for the piston ring cannot be obtained. If the Vickers hardness exceeds 3000 Hv (0.05), the opponent's aggression increases, and the first In the piston ring 10, the wear of the upper and lower surfaces of the piston ring groove formed of aluminum or an alloy thereof is increased. In the second piston ring 13, the partner aggression against the cylinder liner that is the sliding partner increases, and the wear of the cylinder liner increases.

  The thickness of the hard carbon film 2 is not particularly limited, but is usually 1 μm or more and 15 μm or less. If the thickness of the hard carbon film 2 is less than 1 μm, the hard carbon film 2 itself may disappear due to wear, and the wear resistance of the piston ring may not be obtained. This is remarkable in the second piston ring 13 mainly formed. On the other hand, if the thickness of the hard carbon film 2 exceeds 15 μm, “chips” are likely to occur, and the film formation time increases, resulting in an increase in cost.

  FIG. 7 is a photomicrograph showing the structure of the hard carbon film formed on the upper and lower surfaces of the first piston ring 10 of the present invention, FIG. 7 (A) is a surface photograph, and FIG. ) Is a cross-sectional photograph. The structure of the hard carbon film 2 is a characteristic configuration of the present invention, and has a columnar structure 2x as shown in FIG. As shown in FIGS. 7A and 7B, this columnar structure 2x is characterized in that an innumerable columnar structure is formed on the base material 1. The width of one unit of each columnar structure (the width measured in the direction along the surface direction of the base material 1) is not particularly limited, but is in the range of 100 nm to 800 nm, and is shown in FIG. In the example shown, it can be seen that the width of one unit of each columnar structure is about 500 nm. In addition, the width | variety can also be called the diameter of one unit of columnar structure | tissue so that the surface photograph shown to FIG. 7 (A) may show.

  The surface of the hard carbon film 2 exhibiting such a structure has irregularities. Since such irregularities function as an oil reservoir, the opponent attack can be reduced, and an especially excellent suppression effect can be obtained with respect to Al adhesion that is easily generated between the piston ring groove.

  Moreover, it is preferable that the surface roughness of the hard carbon film 2 which shows the said structure | form form is 1.5 micrometers or more by 10-point average roughness Rz based on JISB0601 (1994). Since the surface of the hard carbon film 2 having such a surface roughness acts as an oil reservoir as described above, it is possible to reduce the attack of the opponent and to prevent Al adhesion easily occurring between the piston ring groove. In particular, an excellent suppression effect is achieved. The upper limit of the surface roughness is not particularly limited, but is usually about 3.5 μm.

  The surface roughness of the hard carbon film 2 on the outer peripheral sliding surface 6 formed when the hard carbon film 2x having the above-described structure is formed on the upper and lower surfaces is a ten-point average roughness based on JIS B0601 (1994). The thickness Rz is preferably less than 1.5 μm, more preferably 0.4 μm or more and 1.0 μm or less. Since the surface roughness Rz of the hard carbon film 2 formed on the outer peripheral sliding surface 6 is less than 1.5 μm, it has excellent wear resistance while reducing the partner's aggression against the cylinder liner which is the counterpart material. Obtainable. The surface roughness is measured by a surface roughness measuring device in accordance with JIS B0601 (1994).

  In the first piston ring 10 of the present invention, as shown in FIGS. 1 to 3, the hard carbon film 2 having the above-described component composition and structure is formed on at least the upper surface 8 and the lower surface 9 (10A, 10E, 11A, 11B, 11E, 12A, 12B, 12E) may be piston rings 10B, 10F, 11D, 12D formed on the outer peripheral sliding surface 6 in addition to the upper surface 8 and the lower surface 9, or the upper surface 8 The piston rings 10D, 10H, 11F, 11G, 12F, and 12G may be formed on the inner peripheral surface 7 in addition to the lower surface 9, and the outer peripheral sliding surface 6 and the inner surface in addition to the upper surface 8 and the lower surface 9. The piston rings 10C, 10G, 11C, and 12C may be formed on both of the peripheral surfaces 7, that is, on the entire periphery. The hard carbon film 2 formed on the outer peripheral sliding surface 6 has the following structure similar to that of the hard carbon film 2 mainly formed on the second piston ring 13.

  FIG. 8 is a micrograph showing the structure of the hard carbon film formed on the outer peripheral sliding surface of the second piston ring 13, FIG. 8A is a surface photograph, and FIG. It is a cross-sectional photograph. For example, as shown in FIGS. 2 and 3, the outer peripheral sliding surface 6 is preferably one in which an ion plating film is formed as a base film 3 on a base material 1 and a hard carbon film 2 is formed thereon. Although it can be exemplified, the structure is different from the structure of the hard carbon film 2 formed on the upper surface 8 and the lower surface 9 described above. Specifically, as shown in FIG. 8, the organization form is a dense organization 2y. As shown in FIGS. 8A and 8B, the dense structure 2y is significantly different from the columnar structure 2x formed on the upper surface 8 and the lower surface 9 described above. Since the surface of the hard carbon film 2 showing such a structure is dense, it is a film excellent in initial conformability and wear resistance with respect to the cylinder liner. The vertical scratches in the surface photograph in FIG. 8A are scratches due to lapping of the base material surface before the hard carbon film 2 is formed.

  In addition, the form in such a 2nd piston ring 13 is the hard carbon film of the outer periphery sliding surface 6 formed when forming the hard carbon film 2 of the said structure | tissue form on the upper and lower surfaces like the 1st piston ring 10. 2 is the same form.

  FIG. 9 is an SPM (Scanning Probe Microscope) image showing a more detailed surface form of the hard carbon film formed on the outer peripheral sliding surface of the second piston ring. As shown in FIG. 9, the hard carbon film 2 formed on the outer peripheral sliding surface 6 of the second piston ring 13 has a granular form in which the surface is covered with fine particles. And as for the hard carbon film 2, the outermost surface of an outer periphery sliding surface has a granular form, and the granular form has an average particle diameter of 700 nm or less. A more preferable range is 350 nm to 600 nm or less. The hard carbon film 2 having such a surface form has good initial conformability to the cylinder liner due to the action of the fine particles, and is excellent in wear resistance and scuff resistance. In particular, since it has fine irregularities due to a very large number of fine particles, it is excellent in initial compatibility with a cylinder liner as a counterpart material. The particle size can be adjusted by adjusting the pressure during film formation, the gas flow rate, and the like.

  Moreover, in the 2nd piston ring 13, it is preferable that the particle | grain height of the granular form of the hard carbon film 2 formed in the outer peripheral sliding surface 6 is 70 nm or less. Setting the grain height to 70 nm or less is effective in reducing friction. A preferable range is 30 nm or more and 50 nm or less, and is particularly effective in reducing initial conformability and friction, and further reducing opponent attack. The average grain size and grain height are obtained by measuring the surface morphology of a 3 μm × 3 μm square film in DMF (dynamic force mode) of a scanning probe microscope. As a measurement method at this time, using a scanning probe microscope manufactured by Seiko Instruments Inc., first, the surface morphology of the film surface was observed in a range of 3 μm × 3 μm by DMF, and then the obtained surface morphology image was obtained. The flat treatment was performed, and after the flat treatment, 10 particles were arbitrarily selected and the average particle size and height thereof were measured. The average particle diameter is obtained by selecting 10 arbitrary particles in a 3 μm × 3 μm square region, and measuring and averaging the major axis and minor axis of each particle. In the same region, the grain height was measured by selecting 10 arbitrary grains and changing the color tone.

  In the second piston ring 13, the initial wear height Rpk based on JIS B 0601 (2001) of the hard carbon film 2 formed on the outer peripheral sliding surface 6 is 0.01 μm or more and 0.10 μm or less. Is preferred. Since the surface of the hard carbon film 2 having such an initial wear height Rpk has fine irregularities, it is excellent in initial conformability with a cylinder liner as a counterpart material. A preferable initial wear height Rpk is 0.05 μm or more and 0.09 μm or less, and particularly has an effect of reducing friction. The initial wear height Rpk is measured with a surface roughness measuring device in accordance with JIS B0601 (2001).

  The thickness of the hard carbon film 2 formed on the outer peripheral sliding surface 6 varies depending on the film forming method, but the thickness can be arbitrarily adjusted. When the hard carbon film 2 is formed on the other surface of the outer peripheral sliding surface 6, the thickness of the outer peripheral sliding surface 6 is greater than the thickness of the upper surface 8, the lower surface 9, and the inner peripheral surface 7.

  In the second piston ring 13 of the present invention, as shown in FIGS. 4 to 6, the hard carbon film 2 having the above-described component composition and structure is formed on at least the outer peripheral sliding surface 6 (13A, 13D, 14A, 14D, 15A, 15D) may be piston rings 13B, 13E, 14B, 14E, 15B, 15E formed on the upper surface 8 and the lower surface 9 in addition to the outer peripheral sliding surface 6, or the outer peripheral sliding surface. In addition to the moving surface 6, the upper surface 8, the lower surface 9, and the inner peripheral surface 7, that is, piston rings 13C, 13F, 14C, 14F, 15C, and 15F formed on the entire periphery may be used.

  As a method of forming the hard carbon film 2 formed on the first and second piston rings 10 and 13, a so-called PVD method such as a reactive ion plating method or a reactive sputtering method, or a CVD such as a plasma CVD method is used. Although it can be formed by various methods such as a method, in the present invention, a CVD method such as a plasma CVD method is preferably applicable. For example, in the plasma CVD method, a thickness difference may occur in each part of the workpiece based on the shape factor of the workpiece. In particular, as in the first and second piston rings 10 and 13 of the present invention, In a work to be deposited on a jig, the outer peripheral sliding surface 6 tends to be the thickest, the upper surface 8 and the lower surface 9 continue, and the inner peripheral surface 7 tends to be the thinnest. Such a difference in thickness can be controlled by adjusting the gap between adjacent piston ring base materials 1 when attaching the piston ring base material 1 to a jig. For example, increasing the gap Thus, the difference in thickness between the surfaces can be reduced, and the difference in thickness between the surfaces can be increased by reducing the gap.

  Among the CVD methods, a PIG (Phillips Ion Gauge) type plasma CVD method is particularly preferable. This PIG plasma CVD method is characterized in that since the plasma source is close to the outer peripheral sliding surface of the piston ring, a denser film can be formed, and it can be easily formed on the upper and lower surfaces. It is preferable for obtaining the piston ring of the present invention in terms of the functionality of the membrane and the ease of coating.

  Next, other layers will be described.

  In the first and second piston rings 10 and 13 of the present invention, any one selected from a sputtering film, an ion plating film, a plating film, and a nitride layer is used as a surface film, or as a base film or a base layer. Preferably, it is formed on the outer peripheral sliding surface 6. Here, when these films are provided as surface films, the hard carbon film 2 is not formed on these films, and when these films are provided as a base film or a base layer, This is a case where the hard carbon film 2 is formed on this film. In the following description, these are collectively referred to as “underlying film 3” for convenience.

  In the first piston ring 10, the base film 3 may be formed only on the outer peripheral sliding surface 6 as shown in FIGS. 2 and 3, or formed on the outer peripheral sliding surface 6, the upper surface 8, and the lower surface 9. It may be formed on the inner peripheral surface 7, the upper surface 8 and the lower surface 9, or may be formed on the entire circumference of the outer peripheral sliding surface 6, the inner peripheral surface 7, the upper surface 8 and the lower surface 9, It can be provided as necessary. In particular, it is preferable to form the outer peripheral sliding surface 6. On the other hand, the second piston ring 13 may be formed only on the outer peripheral sliding surface 6 as shown in FIGS. 5 and 6, or may be formed on the outer peripheral sliding surface 6, the upper surface 8 and the lower surface 9. Alternatively, it may be formed on the entire circumference of the outer peripheral sliding surface 6, the inner peripheral surface 7, the upper surface 8, and the lower surface 9, and may be provided as necessary. In particular, it is preferable to form the outer peripheral sliding surface 6.

  Since any base film 3 selected from a sputtering film, an ion plating film, a plating film, and a nitride layer is hard and tough, the wear resistance on the surface on which the base film 3 is formed is further improved. However, even when the hard carbon film 2 is not formed, it can be formed on the outer peripheral sliding surface 6 as a surface film, and the outer peripheral sliding surface 6 can be provided with preferable wear resistance. it can. Further, if the second piston ring 13 is formed as the base film 3 of the hard carbon film 2 formed on the outer peripheral sliding surface 6, the wear resistance against the cylinder liner can be further improved, and the hard Even when the carbon film 2 is worn away, the wear resistance can be maintained by the presence of the base film 3.

  A preferable undercoat film 3 is an ion plating film formed by an ion plating method, and in particular, Cr—N, Ti—N, Cr—O—N, Cr—B—N, Cr—B—V—N. It is preferable that it is a hard film. Since the ion plating film is hard and tough, it is possible to further improve the wear resistance of the outer peripheral sliding surface 6 of the first and second piston rings 10 and 13 acting as a sliding surface. Note that the base film 3 may be a sputtering film formed by a reactive sputtering method or the like instead of the ion plating method. The thickness of the base film 3 is preferably about 1 to 50 μm.

  The means for forming the plating film and the nitride layer is not particularly limited. The plating film may be a single layer plating film, a multilayer plating film, or a composite plating film. The nitride layer may be an ion nitride layer, a gas nitride layer, or a soft nitride layer, and the formation means is not particularly limited.

  An adhesive film (not shown) containing at least Cr or Ti can be formed between the hard carbon film 2 and the piston ring base material 1 on the piston ring base material 1. By forming such an adhesion film between the piston ring base material 1 and the hard carbon film 2, the adhesion can be improved. As the adhesion film, a metal chromium film or a metal titanium film is usually applied, and it is desirable to form the adhesion film by a sputtering method, an ion plating method or a plating method. The thickness of the adhesion film is preferably 0.1 to 10 μm.

  The SiC film 4 can be provided as a lower layer that is in direct contact with the hard carbon film 2. This SiC film 4 is for further improving the adhesion of the hard carbon film 2 and is provided in various forms shown in FIGS. 1, 3, 4 and 6. The SiC film 4 may be a single layer or a laminate of two or more layers. In the case of a single layer, an SiC film having a silicon content higher than that of the hard carbon film 2 can be provided, and in the case of a laminate, an SiC film having a silicon content higher than that of the hard carbon film 2 and silicon An SiC gradient film having a content lower than that of the SiC film and higher than that of the hard carbon film 2 and gradually decreasing toward the hard carbon film 2 can be provided in that order. Such an SiC film 4 has an effect of adjusting the overall internal stress, and can further improve the adhesion of the hard carbon film 2. The thickness of the SiC film 4 is preferably about 0.05 to 5 μm.

(Manufacturing method of piston ring)
The piston ring manufacturing method of the present invention is a method of forming the hard carbon film 2 on at least one of the outer peripheral sliding surface 6 and the upper and lower surfaces 8 and 9 of the piston rings 10 and 13 by plasma CVD. In this method, the upper surface 8 and the lower surface 9 of the piston rings 10 and 13 are arranged so as to be parallel to the ion flow from the plasma generation source, and the outer peripheral sliding surface 6 is against the ion flow from the plasma generation source. The hard carbon film 2 has an oxygen content of 1 atomic% to 10 atomic%, a hydrogen content of 10 atomic% to 40 atomic%, and a silicon content. The film is formed so as to be 0.1 atomic% or more and 20 atomic% or less. In the piston rings 10 and 13 manufactured by such a method, the structure of the hard carbon film 2 formed on the upper surface 8 and the lower surface 9 is a columnar structure, and the structure formed on the outer peripheral sliding surface 6 is a dense structure. The surface form becomes a granular form.

  Although the manufacturing method of a piston ring is demonstrated in detail, the following examples are the examples and are not limited to the following contents.

  A piston ring base material 1 is prepared, and an adhesion film (not shown) and a base film 3 are formed thereon as necessary. The adhesion film is formed by providing at least one of a sputtering film and an ion plating film as described above, and the base film 3 is also formed as described above by a sputtering film, an ion plating film, a plating film, and It is formed by providing any selected from the nitride layer. Such an adhesion film and the base film 3 can be formed by a sputtering apparatus, an ion plating apparatus, a plating apparatus, a nitriding apparatus, or the like, respectively. If necessary, an SiC film or an SiC gradient film is provided on the adhesion film or the base film 3. These films can be formed by a sputtering apparatus, an ion plating apparatus, a plasma CVD apparatus, or the like.

  Next, the hard carbon film 2 is formed. A piston ring base material 1 on which an adhesion film (not shown), a base film 3 or a SiC film and the like are arbitrarily formed is set on a mounting jig in a chamber of a plasma CVD apparatus, and the inside of the chamber is evacuated. Thereafter, an inert gas such as argon is introduced while rotating the mounting jig, and the surface of the piston ring base material 1 is cleaned by ion bombardment. Thereafter, a hydrocarbon gas such as methane, which is a carbon source, is introduced into the chamber, and further, a silane gas containing oxygen, oxygen, etc. are introduced, activated by plasma, and carbon atoms in the chamber and evaporated metal atoms To form a hard carbon film 2 on the piston ring by depositing a film that falls within the range of the above component composition. The content ratio of each component composition is controlled by adjusting the pressure of the reactive gas containing Si element. In this case, the surface on which the hard carbon film 2 is not formed is subjected to a process such as masking.

  FIG. 10 is an explanatory diagram of a film formation mode of the hard carbon film included in the first and second piston rings of the present invention. As described above, in the hard carbon film 2 according to the present invention, the structure of the upper surface 8 and the lower surface 9 is a columnar structure 2x, the outer peripheral sliding surface 6 is a dense structure, and the surface form is a granular form. However, the reason is considered as follows. That is, since the upper surface 8 and the lower surface 9 are surfaces parallel to the ion flow from the plasma generation source as shown in FIG. 10, the decomposed ions wrap around and reach the upper surface 8 and the lower surface 9. . With such a film formation mode, it is considered that the hard carbon film 2 of the columnar structure 2x that exhibits the effect peculiar to the first piston ring of the present invention is formed on the upper surface 8 and the lower surface 9. On the other hand, since the outer peripheral sliding surface 6 and the inner peripheral surface 7 are surfaces perpendicular to the ion flow from the plasma generation source, the decomposed ions directly reach the outer peripheral sliding surface 6 and the inner peripheral surface 7. It will be. According to such a film formation mode, the hard carbon film 2 of the dense structure 2y made of the particle form exhibiting the effect peculiar to the second piston ring of the present invention is used instead of the columnar structure 2x such as the upper and lower surfaces. It is considered that the surface 7 is formed. Therefore, in this invention, it can manufacture by arrange | positioning the upper surface 8 and the lower surface 9 so that it may become a surface parallel to the ion flow from a plasma generation source.

  Hereinafter, the present invention will be described in more detail with reference to Examples and Comparative Examples.

Example 1
C: 0.8 mass%, Si: 0.4 mass%, Mn: 0.3 mass%, Cr: 17.5 mass%, Mo: 1.1 mass%, V: 0.1 mass%, P: Using a piston ring base material 1 made of SUS440 (17Cr stainless steel) composed of 0.02% by mass, S: 0.02% by mass, balance: iron and inevitable impurities, An ion plating film was formed as the base film 3. This ion plating film uses an ion plating apparatus and has a thickness of 3 μm Cr—N film (Cr: 4.1 mass%, Cr ₂ N: 1.1 mass%, CrN: 94.8 mass%) did.

  Next, an adhesion film and an SiC film are formed in that order from the piston ring base material side on the entire circumference, that is, the outer peripheral sliding surface 6, the inner peripheral surface 7, the upper surface 8 and the lower surface 9, and then the present invention. Such a hard carbon film 2 was formed on the entire circumference by a plasma CVD apparatus. Thus, the first piston ring 12C of Example 1 (see FIG. 3C) was produced. The conditions for forming the adhesion film, the SiC film, and the hard carbon film are as follows.

<Adhesion film>
The adhesion film was formed by a sputtering process. Specifically, in an argon gas atmosphere, the pressure in the vacuum chamber is adjusted to 0.5 Pa, a 4 kW DC power is applied to the sputtering target made of pure Ti, and the sputtering process is performed for 15 to 20 minutes. Formed. The thickness of the adhesion film thus obtained was 0.4 μm for the outer peripheral sliding surface, 0.2 μm for the upper and lower surfaces, and 0.2 μm for the inner peripheral surface.

<SiC film>
The SiC film 4 was formed by a plasma CVD process. Specifically, in an argon gas atmosphere, the pressure in the vacuum chamber was 0.3 Pa, the plasma output was 500 W, and the bias voltage was −550 V. Plasma CVD treatment under such conditions is performed for 5 minutes, and then the flow rate of TMS (tetramethylsilane) gas, acetylene gas and oxygen is continuously changed for 15 minutes, and the plasma gun output is also 500 W over the same time. Gradually increased to 2 kW. At this time, the argon gas flow rate was not changed, and the bias voltage was kept at -550V. The thickness of the SiC film 4 thus obtained was 0.1 μm on the outer peripheral sliding surface, 0.1 μm on the upper and lower surfaces, and 0.1 μm on the inner peripheral surface.

<Hard carbon film>
The hard carbon film 2 was also formed by plasma CVD processing. Specifically, in the argon gas atmosphere, the pressure in the vacuum chamber was 0.2 Pa, the plasma output was kept constant at 2 kW, and the bias voltage was kept constant at −550 V. Plasma CVD treatment under such conditions was performed for 160 minutes. The component composition of the upper and lower surfaces of the hard carbon film 2 is adjusted by controlling reaction conditions such as silane gas pressure in the plasma CVD method, and the component composition is as shown in Table 1, except for hydrogen, silicon, and oxygen. All was carbon. As for the thickness of the hard carbon film 2 thus obtained, the outer peripheral sliding surface was 8.0 μm, the upper and lower surfaces were 4.7 μm, and the inner peripheral surface was 3.8 μm. The total thickness of the adhesion film, the SiC film 4 and the hard carbon film 2 obtained as described above is 8.5 μm for the outer peripheral sliding surface 6, 5.0 μm for the upper surface 8, and 5.0 μm for the lower surface 9. The inner peripheral surface 7 was 4.1 μm.

(Example 2)
Example 1 is the same as Example 1 except that, among the reaction conditions in the plasma CVD apparatus, the composition of the upper and lower surfaces of the hard carbon film 2 is adjusted as shown in Table 1 by changing the gas flow rate and the chamber internal pressure. In the same manner as described above, the first piston ring of Example 2 was produced. The thickness of each surface of the obtained hard carbon film 2 was also the same as in Example 1.

(Example 3, Comparative Examples 1-5)
Example 3 is the same as Example 1 except that the reaction conditions in the plasma CVD apparatus are changed to adjust the composition of the upper and lower surfaces of the hard carbon film 2 as shown in Table 1. The 1st piston rings of comparative examples 1-5 were produced, respectively. In Comparative Examples 1 to 3, in order to obtain a dense structure on the upper and lower surfaces of the piston ring, the upper and lower surfaces were set so as to face the plasma generation source, and a hard carbon film made of the dense structure was formed. The thickness of each surface of the obtained hard carbon film 2 was the same as in Example 1.

(Examples 4-15, Comparative Examples 6-14)
In Example 1, except that the reaction conditions in the plasma CVD apparatus were changed to adjust the component composition of the hard carbon film 2 on the outer peripheral sliding surface 6 as shown in Table 2, the same as in Example 1, Second piston rings 15C (see FIG. 6A) of Examples 4 to 15 and Comparative Examples 6 to 14 were produced. The thickness of the outer peripheral sliding surface of the obtained hard carbon film 2y was 8.0 μm. The total film thickness of the adhesion film, the SiC film 4 and the hard carbon film 2 obtained as described above was 8.5 μm. The Vickers hardness was in the range of 1500 to 3000.

(Abrasion test)
For the wear test, an Amsler type wear tester 20 shown in FIG. 11 is used, a specimen 21 (7 mm × 8 mm × 5 mm) is used as a fixed piece, and the mating material 22 (rotating piece) has a donut shape (outer diameter 40 mm, A sample having an inner diameter of 16 mm and a thickness of 10 mm was used, the specimen 21 and the counterpart material 22 were brought into contact with each other, and a load P was applied. As the test material 21, the test materials of Examples 1 to 3 and Comparative Examples 1 to 5 were used, and the lower surface of each test material 21 on which the hard carbon film 2x was formed was measured. The friction coefficient test conditions using each test material 21 were as follows: Lubricating oil 23: Krysef H8 (No. 1 spindle oil equivalent), oil temperature: 80 ° C., peripheral speed: 1 m / sec (478 rpm), load: 1471.5 N Test time: Boron cast iron was used as the counterpart material 22 under the condition of 7 hours. The counterpart material 22 made of boron cast iron is ground into a predetermined shape, and then subjected to sequential surface grinding by changing the fineness of the grinding wheel, and finally 2 μm Rz (10-point average roughness, in accordance with JIS B0601 (1994). )). The coefficient of friction was calculated by dividing the frictional resistance by the load.

  The wear resistance index shown in Table 1 compares the wear index of each of the test materials of Examples 1 to 3 and Comparative Examples 2 to 5 as a relative ratio to the wear index of the test material corresponding to Comparative Example 1. The abrasion resistance index was used. Therefore, the smaller the wear resistance index of each test material is, the smaller the wear amount is. Each test piece corresponding to Examples 1 to 3 had a small wear resistance index, and was markedly superior in wear resistance than the test pieces corresponding to Comparative Examples 1 to 5.

(Groove wear test)
In the groove wear test, an NPR type groove wear tester shown in FIG. 12 was used, and the gas seal rings and specimens of Examples 1 to 3 and Comparative Examples 1 to 5 were formed on the piston ring groove of the piston member (Al material). (Test-ring) is mounted, a motor (not shown) is driven under the following test conditions, and gas pressure is introduced from the liner member 31 side while rotating eccentrically in the radial direction, so that the gas seal ring 33 has a ring groove 35A. The lower test material 32 was seated on the lower surface of the ring groove 35B to reproduce the sliding of the piston member and the piston ring in the actual machine, and a groove wear test was performed.

Groove wear test;
Eccentricity: 0.3mm
Eccentricity cycle: 50Hz
Gas pressure: 0.5 MPa
Groove bottom temperature: 200 ° C
Oil supply: Supply mist oil for 8 sec every 10 min. Operation time: 25 hours

  After the test, the profiles of the piston member 34 and the specimen 32 are measured, the wear amount is calculated, and compared as a relative ratio to the abrasion index of the specimen corresponding to Comparative Example 1, It was. Therefore, the opponent attack resistance index is smaller as 100, indicating that the opponent attack is smaller. From the opponent attack resistance index shown in Table 1, each of the test pieces corresponding to Examples 1 to 3 has a smaller opponent attack index, which is superior to the test pieces corresponding to Comparative Examples 1 to 5. It was. Moreover, generation | occurrence | production of Al adhesion was not seen in the lower surface of a test material and the lower surface of the ring groove 35 in any of Examples 1-3 at this time.

(Reciprocating friction and wear test)
A reciprocating friction and wear test machine 41 shown in FIG. 13 was used to perform a reciprocating friction and wear test between the second piston ring 13 and an aluminum bore as a piston material. Sample materials 42 of Examples 4 to 15 and Comparative Examples 6 to 14 were used as the piston ring material, and Si: 24.0% by mass, Cu: 4.0% by mass, Mg: 1.0% by mass, Fe: 0.1% by mass, Mn: 0.1% by mass, balance: Al and an aluminum alloy having a composition of inevitable impurities were used as the test material 45 for evaluation. In this reciprocating friction and wear tester 41, the specimen 42 (diameter thickness: 3.1 mm, axial thickness: 1.2 mm, diameter: 87 mm) is cut out 8 mm from the joint and supported by the fixed block 43. ing. The test material 42 was loaded with a downward load by a hydraulic cylinder 44 from above, and pressed a test material 45 (flat plate shape: 25 mm × 135 mm × 25 mm) as a piston material. The specimen 45 was supported by a movable block 46 and reciprocated horizontally and in a plane by a crank mechanism 47. Reference numeral 48 denotes a load cell.

Test conditions;
Rotation speed: 750rpm
Stroke: 20mm
Load: 10N
Time: 12 hours Oil: Supply every 2-5 minutes

  After the test, the wear amount of the test material (piston ring material) 43 and the test material (piston material) 45 is measured, and compared as a relative ratio to the wear amount of the test material corresponding to Comparative Example 9, The wear resistance index was used. Therefore, the smaller the wear resistance index is, the smaller the wear amount is. From the wear resistance index shown in Table 2, each of the test pieces corresponding to Examples 4 to 15 has a smaller wear amount for both the piston material and the piston ring material, and is more wear resistant than the test pieces corresponding to Comparative Examples 6 to 14. It was excellent. From this, it was confirmed that while maintaining the wear resistance of the piston ring, it is excellent in the opponent attack resistance that suppresses the wear of the piston as the counterpart material.

(Other evaluation)
The surface roughness is measured with a surface roughness measuring device (manufactured by Tokyo Seimitsu Co., Ltd.) according to JIS B0601 (2001), and the upper and lower surfaces of the first piston rings of Examples 1 to 3 and Comparative Examples 1 to 5 are measured. Was evaluated by 10-point average roughness Rz. On the other hand, the outer peripheral sliding surfaces of the second piston rings of Examples 4 to 15 and Comparative Examples 6 to 14 were evaluated by the initial wear height Rpk. The results are shown in Table 2. Moreover, the component composition in the hard carbon film 2 was quantified using a backscattering measuring device (manufactured by Nissin High Voltage Co., Ltd.). Moreover, the cross-sectional form of the hard carbon film 2 was observed using a metal microscope, and the surface form was observed using an X-ray microanalyzer (EPMA). Moreover, the average particle diameter and the height of the outer peripheral sliding surface were measured using a scanning probe microscope (manufactured by Seiko Instruments Inc.). The hardness was measured using a micro Vickers hardness tester (manufactured by Akashi Co., Ltd.). The thickness of the hard carbon film 2 is calculated from the cross-sectional observation described above, and the thickness is adjusted so that the thickness of the hard carbon film 2 is 8.0 μm in all cases, and the adhesion film and the SiC The thickness of the hard carbon film 2 was adjusted to 8.5 μm together with the film 4, and the structure of the hard carbon film 2 was dense.

It is typical sectional drawing which shows the example of the 1st piston ring of this invention. It is typical sectional drawing which shows the other example of the 1st piston ring of this invention. It is typical sectional drawing which shows the other example of the 1st piston ring of this invention. It is typical sectional drawing which shows the example of the 2nd piston ring of this invention. It is typical sectional drawing which shows the other example of the 2nd piston ring of this invention. It is typical sectional drawing which shows the other example of the 2nd piston ring of this invention. It is a microscope picture which shows the structure | tissue form of the hard carbon film formed in the upper surface and the lower surface, FIG. 7 (A) is a surface photograph, FIG.7 (B) is a cross-sectional photograph. It is a microscope picture which shows the structure | tissue form of the hard carbon film formed in the outer periphery sliding surface, FIG. 8 (A) is a surface photograph, and FIG. 8 (B) is a cross-sectional photograph. It is a SPM image which shows the more detailed surface form of the hard carbon film formed in the outer periphery sliding surface. It is explanatory drawing of the film-forming aspect of the hard carbon film which the piston ring of this invention has. It is a block diagram of the configuration of an Amsler type wear tester used for measurement. It is a block diagram showing the configuration of a groove wear tester used for measurement. It is a block diagram of the reciprocating friction and wear tester used for the measurement.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Base material 2 Hard carbon film 2x Columnar structure 2y Dense structure 3 Base film 4 SiC film 6 Outer peripheral sliding surface 7 Inner peripheral surface 8 Upper surface 9 Lower surface 10, 11, 12, 13, 14, 15 Piston ring

Claims (12)

A piston ring having a hard carbon film formed on at least the upper surface and the lower surface,
The hard carbon film has an oxygen content of 1 atomic% to 10 atomic%, a hydrogen content of 10 atomic% to 40 atomic%, and a silicon content of 0.1 atomic% to 20 atomic%. And
The piston ring, wherein the hard carbon film formed on the upper surface and the lower surface has a columnar structure.   2. The hard carbon film is further formed continuously on the outer peripheral sliding surface of the piston ring, and the structure of the hard carbon film formed on the outer peripheral sliding surface is a dense structure. Piston ring as described in.   The piston ring according to claim 1 or 2, wherein the surface roughness of the hard carbon film composed of the columnar structure is 1.5 µm or more in terms of a ten-point average roughness Rz based on JIS B0601 (1994). A piston ring having a hard carbon film formed on at least the outer peripheral sliding surface,
The hard carbon film has an oxygen content of 1 atomic% to 10 atomic%, a hydrogen content of 10 atomic% to 40 atomic%, and a silicon content of 0.1 atomic% to 20 atomic%. And
The hard carbon film formed on the outer peripheral sliding surface has a granular form on the surface, and the granular form has an average particle diameter of 700 nm or less.   The piston ring according to claim 4, wherein the granular form has a height of 70 nm or less.   6. The hard carbon film formed on the outer peripheral sliding surface has an initial wear height Rpk based on JIS B 0601 (2001) of 0.01 μm or more and 0.10 μm or less. The piston ring as described.   Any one selected from a sputtering film, an ion plating film, a plating film, and a nitride layer is formed on the outer peripheral sliding surface as a surface film, or as a base film or a base layer of the hard carbon film. The piston ring according to any one of claims 2 to 6.   8. An adhesion film containing at least Cr or Ti and an SiC film are formed in that order from the base material side between the hard carbon film and the piston ring base material. The piston ring according to any one of the above. A piston ring manufacturing method for forming a hard carbon film by plasma CVD on at least one of an outer peripheral sliding surface and an upper and lower surface of a piston ring,
The upper and lower surfaces of the piston ring are arranged so as to be parallel to the ion flow from the plasma generation source, and the outer peripheral sliding surface is arranged to be a plane perpendicular to the ion flow from the plasma generation source. And
The hard carbon film has an oxygen content of 1 atomic% to 10 atomic%, a hydrogen content of 10 atomic% to 40 atomic%, and a silicon content of 0.1 atomic% to 20 atomic%. A method for producing a piston ring, characterized in that the film is formed as follows.   The manufacturing method of the piston ring of Claim 9 whose structure | tissue form of the hard carbon film formed in the said upper surface and lower surface is columnar structure | tissue.   The manufacturing method of the piston ring of Claim 9 or 10 whose structure | tissue form of the hard carbon film formed in the said outer periphery sliding surface is a dense structure | tissue, and whose surface form is a granular form.   The manufacturing method of the piston ring according to claim 11, wherein the granular form has an average particle size of 700 nm or less and a particle height of 70 nm or less.

Images