WO2018164139A1 - Palier à roulement et son procédé de fabrication - Google Patents

Palier à roulement et son procédé de fabrication Download PDF

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Publication number
WO2018164139A1
WO2018164139A1 PCT/JP2018/008623 JP2018008623W WO2018164139A1 WO 2018164139 A1 WO2018164139 A1 WO 2018164139A1 JP 2018008623 W JP2018008623 W JP 2018008623W WO 2018164139 A1 WO2018164139 A1 WO 2018164139A1
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WIPO (PCT)
Prior art keywords
layer
hard film
rolling bearing
mixed layer
rolling
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PCT/JP2018/008623
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English (en)
Japanese (ja)
Inventor
雅樹 中西
三上　英信
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Ntn株式会社
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Publication date
Priority claimed from JP2017218848A external-priority patent/JP2018146108A/ja
Application filed by Ntn株式会社 filed Critical Ntn株式会社
Priority to US16/492,090 priority Critical patent/US20200408261A1/en
Publication of WO2018164139A1 publication Critical patent/WO2018164139A1/fr

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    • C—CHEMISTRY; METALLURGY
    • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
    • C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
    • C23C14/00—Coating by vacuum evaporation, by sputtering or by ion implantation of the coating forming material
    • C23C14/06—Coating by vacuum evaporation, by sputtering or by ion implantation of the coating forming material characterised by the coating material
    • C—CHEMISTRY; METALLURGY
    • C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
    • C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
    • C23C14/00—Coating by vacuum evaporation, by sputtering or by ion implantation of the coating forming material
    • C23C14/22—Coating by vacuum evaporation, by sputtering or by ion implantation of the coating forming material characterised by the process of coating
    • C23C14/34—Sputtering
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16C—SHAFTS; FLEXIBLE SHAFTS; ELEMENTS OR CRANKSHAFT MECHANISMS; ROTARY BODIES OTHER THAN GEARING ELEMENTS; BEARINGS
    • F16C33/00—Parts of bearings; Special methods for making bearings or parts thereof
    • F16C33/30—Parts of ball or roller bearings
    • F16C33/32—Balls
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16C—SHAFTS; FLEXIBLE SHAFTS; ELEMENTS OR CRANKSHAFT MECHANISMS; ROTARY BODIES OTHER THAN GEARING ELEMENTS; BEARINGS
    • F16C33/00—Parts of bearings; Special methods for making bearings or parts thereof
    • F16C33/30—Parts of ball or roller bearings
    • F16C33/34—Rollers; Needles
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16C—SHAFTS; FLEXIBLE SHAFTS; ELEMENTS OR CRANKSHAFT MECHANISMS; ROTARY BODIES OTHER THAN GEARING ELEMENTS; BEARINGS
    • F16C33/00—Parts of bearings; Special methods for making bearings or parts thereof
    • F16C33/30—Parts of ball or roller bearings
    • F16C33/58—Raceways; Race rings
    • F16C33/62—Selection of substances
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16C—SHAFTS; FLEXIBLE SHAFTS; ELEMENTS OR CRANKSHAFT MECHANISMS; ROTARY BODIES OTHER THAN GEARING ELEMENTS; BEARINGS
    • F16C33/00—Parts of bearings; Special methods for making bearings or parts thereof
    • F16C33/30—Parts of ball or roller bearings
    • F16C33/58—Raceways; Race rings
    • F16C33/64—Special methods of manufacture
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16C—SHAFTS; FLEXIBLE SHAFTS; ELEMENTS OR CRANKSHAFT MECHANISMS; ROTARY BODIES OTHER THAN GEARING ELEMENTS; BEARINGS
    • F16C2206/00—Materials with ceramics, cermets, hard carbon or similar non-metallic hard materials as main constituents
    • F16C2206/02—Carbon based material
    • F16C2206/04—Diamond like carbon [DLC]
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16C—SHAFTS; FLEXIBLE SHAFTS; ELEMENTS OR CRANKSHAFT MECHANISMS; ROTARY BODIES OTHER THAN GEARING ELEMENTS; BEARINGS
    • F16C2206/00—Materials with ceramics, cermets, hard carbon or similar non-metallic hard materials as main constituents
    • F16C2206/80—Cermets, i.e. composites of ceramics and metal
    • F16C2206/82—Cermets, i.e. composites of ceramics and metal based on tungsten carbide [WC]

Definitions

  • the present invention relates to a rolling bearing and a manufacturing method thereof, and more specifically to a rolling bearing in which a hard film containing diamond-like carbon is formed on the inner ring, outer ring, and rolling element surface, and a manufacturing method thereof.
  • the hard carbon film is a hard film generally called diamond-like carbon (hereinafter referred to as DLC.
  • DLC diamond-like carbon
  • a film or layer mainly composed of DLC is also referred to as a DLC film or a DLC layer).
  • hard carbon such as hard amorphous carbon, amorphous carbon, hard amorphous carbon, i-carbon, diamond-like carbon, and these terms are clearly distinguished. Not.
  • DLC diamond-based liquid crystal display
  • DLC diamond-based liquid crystal display
  • PVD physical vapor deposition
  • CVD chemical vapor deposition
  • UBMS unbalanced magnetron sputtering
  • DLC film has been formed on the raceway surface of the bearing ring of the rolling bearing and the rolling surface of the rolling element.
  • a DLC film generates extremely large internal stress during film formation.
  • the DLC film has high hardness and Young's modulus, but has extremely low deformability. For this reason, the DLC film has weaknesses such as weak adhesion to the substrate and easy peeling. In the case where a DLC film is formed on the raceway surface of the bearing ring of the rolling bearing or the rolling surface of the rolling element, it is necessary to improve the adhesion.
  • an intermediate layer is provided between the base material and the DLC film to improve the adhesion of the DLC film.
  • chromium hereinafter, at least one of Cr (hereinafter referred to as Cr), tungsten (hereinafter referred to as W), titanium (hereinafter referred to as Ti), silicon (hereinafter referred to as Si), nickel (hereinafter referred to as Ni), and iron
  • Cr Cr
  • W tungsten
  • Ti titanium
  • Si silicon
  • Ni nickel
  • iron an underlayer having an element-containing composition, a constituent element of the underlayer and carbon, an intermediate layer having a carbon content rate opposite to the underlayer and larger than that of the underlayer, and argon and carbon
  • a rolling device in which a DLC layer having a content rate of 0.02 mass% or more and 5 mass% or less is formed in this order (see Japanese Patent Application Laid-Open No. 2003-314560).
  • an object of the present invention is to provide a rolling bearing having excellent durability.
  • the rolling bearing according to the present disclosure includes an inner ring, an outer ring, a plurality of rolling elements, and a hard film.
  • the inner ring has an inner ring raceway surface on the outer periphery.
  • the outer ring has an outer ring raceway surface on the inner periphery.
  • the plurality of rolling elements roll between the inner ring raceway surface and the outer ring raceway surface.
  • the hard film is formed on at least one surface selected from the group consisting of an inner ring, an outer ring, and a rolling element.
  • the inner ring, the outer ring, and the plurality of rolling elements are made of an iron-based material.
  • the hard film includes an underlayer, a mixed layer, and a surface layer.
  • the underlayer is a layer mainly composed of chromium and formed directly on the surface.
  • the mixed layer is a layer mainly composed of tungsten carbide (WC) and diamond-like carbon (DLC) formed on the base layer.
  • the surface layer is a layer mainly composed of diamond-like carbon (DLC) formed on the mixed layer.
  • the content of tungsten carbide (WC) in the mixed layer decreases continuously or stepwise from the base layer side to the surface layer side, and the diamond-like carbon (DLC) content in the mixed layer This is a layer with a higher rate.
  • the rolling bearing manufacturing method includes a step of preparing an inner ring, an outer ring, and a rolling element, and a step of forming a hard film.
  • the hard film is formed on at least one surface selected from the group consisting of an inner ring, an outer ring, and a rolling element.
  • an unbalanced magnetron sputtering apparatus using argon gas as the sputtering gas is used.
  • a graphite target and a hydrocarbon gas are used in combination as a carbon supply source, and the ratio of the introduction amount of the hydrocarbon gas to the introduction amount 100 of argon gas into the apparatus is 1 or more and 10 or less.
  • the surface layer is formed by depositing carbon atoms generated from the carbon supply source on the mixed layer.
  • the durability is improved by improving the peel resistance of the hard film including the layer mainly composed of DLC formed on the inner / outer ring raceway surfaces of the rolling bearing and exhibiting the original characteristics of DLC.
  • Rolling bearings can be realized.
  • a hard film such as a DLC film has residual stress in the film.
  • the residual stress varies greatly depending on the film structure of the hard film, the film formation conditions, and the shape of the substrate on which the hard film is formed.
  • the present inventors have unexpectedly discovered that the influence of the substrate shape on the residual stress is large. For example, in a hard film formed on a flat surface, there is no peeling immediately after film formation, and the critical peeling load in the scratch test is large.
  • a hard film having the same structure is formed on curved surfaces such as the inner ring raceway surface and the outer ring raceway surface of the rolling bearing, it peels off immediately after film formation or does not peel immediately after film formation, but peels off during use.
  • a hard film formed on the inner ring raceway surface, outer ring raceway surface, and rolling surface of the rolling element, which are curved surfaces, is a base layer (a layer mainly composed of Cr). It has been found that peeling resistance can be greatly improved by limiting to a predetermined structure comprising a mixed layer (layer having a WC / DLC gradient composition) and a surface layer (layer mainly composed of DLC).
  • the hard film having such a configuration can suppress peeling even under actual use conditions of the bearing.
  • the indentation hardness of the surface layer was 10 to 20 GPa, the peel resistance could be further improved.
  • the present invention has been made based on such findings.
  • ⁇ Configuration of rolling bearing> 1 to 3 are schematic cross-sectional views of rolling bearings according to an embodiment of the present invention (hereinafter also referred to as this embodiment).
  • 4 is a schematic cross-sectional view of a rolling element of the rolling bearing shown in FIG.
  • FIG. 5 is a schematic partial sectional view of a hard film of the rolling bearing shown in FIG.
  • FIG. 1 shows a cross-sectional view of a deep groove ball bearing which is an example of a rolling bearing in which a hard film described later is formed on the inner ring raceway surface.
  • FIG. 2 shows a cross-sectional view of a deep groove ball bearing in which a hard film described later is formed on the outer ring raceway surface.
  • FIG. 3 shows a cross-sectional view of a deep groove ball bearing in which a hard film is formed on the rolling surface of the rolling element.
  • 1 to 3 includes an inner ring 2 having an inner ring raceway surface 2a on an outer periphery, an outer ring 3 having an outer ring raceway surface 3a on an inner periphery, and an inner ring raceway surface 2a and an outer ring raceway surface 3a. And a plurality of rolling elements 4 that roll.
  • the rolling elements 4 are held at regular intervals by a cage 5.
  • the seal member 6 seals both axial end openings between the inner ring and the outer ring.
  • Grease 7 is sealed in the bearing space sealed by the seal member 6. As the grease 7 enclosed around the rolling element 4, a known grease for a rolling bearing can be used.
  • a hard film 8 is formed on the outer peripheral surface of the inner ring 2 including the inner ring raceway surface 2a.
  • a hard film 8 is formed on the inner peripheral surface of the outer ring 3 including the outer ring raceway surface 3a.
  • a hard film 8 is formed on the rolling surface which is the surface of the rolling element 4 as shown in FIG. Since the rolling bearing 1 of FIG. 3 is a deep groove ball bearing, the rolling element 4 is a ball, and its rolling surface is the entire spherical surface. Cylindrical roller bearings or tapered roller bearings may be used as rolling bearings other than those shown in FIGS. At this time, when the hard film 8 is formed on the surface of the rolling element, the hard film 8 may be formed on at least the rolling surface of the rolling element such as the outer peripheral surface of the cylindrical roller. In the rolling bearing 1, the hard film 8 only needs to be formed on at least one surface of the inner ring 2, the outer ring 3, or the rolling element 4 according to the application.
  • the inner ring raceway surface 2a of the deep groove ball bearing is a circular curved surface having an arc-shaped cross section in the axial direction in order to guide the balls as the rolling elements 4.
  • the outer ring raceway surface 3a is also a circular curved surface having an arc-shaped cross section in the axial direction.
  • the radius of curvature of the arc groove is generally about 0.51 dw to 0.54 dw, where dw is the diameter of the ball (steel ball diameter).
  • the inner ring raceway surface and the outer ring raceway surface are at least circumferential in order to guide the rollers of these bearings. It becomes a curved surface in the direction.
  • the inner ring raceway surface and the outer ring raceway surface are curved in the axial direction in addition to the circumferential direction.
  • the inner ring raceway surface 2a and the outer ring raceway surface 3a may have any of the above shapes.
  • the inner ring 2, the outer ring 3, and the rolling element 4, which are bearing members for which the hard film 8 is to be formed, are made of an iron-based material.
  • the iron-based material is a material mainly composed of iron.
  • any steel material generally used as a bearing member can be used, and examples thereof include high carbon chromium bearing steel, carbon steel, tool steel, martensitic stainless steel, and the like.
  • the surface on which the hard film 8 is formed may have a Vickers hardness of Hv650 or higher.
  • Hv650 or more the hardness difference with the hard film 8 (more specifically, the base layer 8a shown in FIG. 5) can be reduced, and the adhesion of the hard film 8 to the bearing member can be improved.
  • a nitride layer may be formed by nitriding treatment on the surface of the bearing member on which the hard film 8 is formed before the hard film 8 is formed.
  • the nitriding treatment it is preferable to perform a plasma nitriding treatment that hardly forms an oxide layer that hinders adhesion on the surface of the bearing member as a base material.
  • the hardness of the nitrided layer surface after the nitriding treatment may be Vickers hardness of Hv1000 or more. In this case, the adhesion of the hard film 8 to the bearing member can be further improved.
  • the surface roughness Ra of the surface of the bearing member on which the hard film 8 is formed may be 0.05 ⁇ m or less. When the surface roughness Ra exceeds 0.05 ⁇ m, it is difficult to form the hard film 8 at the tip of the concavo-convex protrusion on the surface, and the film thickness of the hard film 8 may be locally reduced.
  • the indentation hardness of the surface layer 8c may be 10 GPa or more and 20 GPa or less. In this case, the peel resistance of the hard film 8 can be improved.
  • the indentation hardness may be 18 GPa or less, or 15 GPa or less.
  • the indentation hardness may be 12 GPa or more, or 13 GPa or more.
  • FIG. 5 shows the structure of the hard film 8 in the rolling bearing 1 shown in FIG.
  • the hard film 8 has a three-layer structure including a base layer 8a, a mixed layer 8b, and a surface layer 8c.
  • the foundation layer 8a is a layer formed directly on the inner ring raceway surface 2a of the inner ring 2 and mainly composed of Cr.
  • the mixed layer 8b is formed on the underlayer 8a and is a layer mainly composed of WC and DLC.
  • the surface layer 8c is formed on the mixed layer 8b and is a layer mainly composed of DLC.
  • the WC content in the mixed layer 8b decreases continuously or stepwise from the base layer 8a side to the surface layer 8c side, and the DLC content in the mixed layer 8b. The rate is high.
  • the foundation layer 8a is a layer mainly composed of Cr, the compatibility between the inner ring 2 which is a bearing member made of an iron-based material as a base material and the foundation layer 8a is good. Therefore, compared with the case where W, Ti, Si, etc. are used as the foundation layer 8a, the adhesion of the foundation layer 8a to the bearing member as the base material is high. In particular, when high carbon chromium bearing steel used as a material for the bearing race is used as a material for the bearing member, the base layer 8a mainly composed of Cr is excellent in adhesion to the bearing member.
  • WC used for the mixed layer 8b has intermediate hardness and elastic modulus between Cr and DLC. For this reason, concentration of residual stress after the hard film 8 is formed hardly occurs.
  • the intermediate in the hard film 8 Material selection in the mixed layer 8b as a layer is also an important factor.
  • the mixed layer 8b has a gradient composition in which the WC content decreases toward the surface layer 8c and the DLC content increases. Therefore, the mixed layer 8b has excellent adhesion on both the interface with the base layer 8a and the interface with the surface layer 8c.
  • the mixed layer 8b has a structure in which WC and DLC are physically combined, and the DLC content is increased on the surface layer 8c side in the mixed layer 8b. Therefore, the surface layer 8c and the mixed layer 8b Excellent adhesion.
  • the surface layer 8c is a film mainly composed of DLC.
  • the surface layer 8c has an inclined layer portion 8d whose hardness increases continuously or stepwise from the mixed layer 8b side to the opposite side (upper surface side of the surface layer 8c) on the side adjacent to the mixed layer 8b. preferable. This is because when the bias voltage at the time of film formation is different between the mixed layer 8b and the surface layer 8c, the bias voltage is changed continuously or stepwise in order to avoid a sudden change in the bias voltage (for example, a set value of the bias voltage). This is the part obtained by raising the The inclined layer portion 8d changes the bias voltage in this way, and as a result, the hardness changes in the thickness direction of the surface layer 8c as described above.
  • the reason why the hardness increases continuously or stepwise is that the constituent ratio of the graphite structure (sp2) and the diamond structure (sp3) in the DLC structure is biased toward the latter as the bias voltage increases. Thereby, a sudden change in hardness in the interface region between the mixed layer 8b and the surface layer 8c is reduced, and the adhesion between the mixed layer 8b and the surface layer 8c is further improved.
  • the film thickness of the hard film 8 (the total film thickness of the base layer 8a, the mixed layer 8b, and the surface layer 8c) may be 0.5 ⁇ m or more and 3.0 ⁇ m or less. If the film thickness is less than 0.5 ⁇ m, the hard film 8 may have insufficient wear resistance and mechanical strength. If the film thickness exceeds 3.0 ⁇ m, the hard film 8 may be easily peeled off. Furthermore, the ratio of the thickness of the surface layer 8c to the thickness of the hard film 8 is preferably 0.8 or less. If this ratio exceeds 0.8, the gradient structure for physically bonding WC and DLC in the mixed layer 8b becomes a discontinuous structure, so that the adhesion of the hard film 8 may deteriorate.
  • the hard film 8 has a three-layer structure including the base layer 8a, the mixed layer 8b, and the surface layer 8c having the above-described composition, thereby realizing excellent peeling resistance.
  • a rolling bearing 1 includes an inner ring 2, an outer ring 3, a plurality of rolling elements 4, and a hard film 8.
  • the inner ring 2 has an inner ring raceway surface 2a on the outer periphery.
  • the outer ring 3 has an outer ring raceway surface 3a on the inner periphery.
  • the plurality of rolling elements 4 roll between the inner ring raceway surface 2a and the outer ring raceway surface 3a.
  • the hard film 8 is formed on at least one surface selected from the group consisting of the inner ring 2, the outer ring 3, and the rolling elements 4.
  • the inner ring 2, the outer ring 3, and the plurality of rolling elements 4 are made of an iron-based material.
  • the hard film 8 includes a base layer 8a, a mixed layer 8b, and a surface layer 8c.
  • the underlayer 8a is a layer mainly composed of chromium (Cr), which is directly formed on the surface.
  • the mixed layer 8b is a layer mainly composed of tungsten carbide (WC) and diamond-like carbon (DLC) formed on the base layer 8a.
  • the surface layer 8c is a layer mainly composed of diamond-like carbon (DLC) formed on the mixed layer 8b.
  • the content of tungsten carbide (WC) in the mixed layer 8b decreases continuously or stepwise from the base layer 8a side to the surface layer 8c side, so that the diamond-like carbon ( DLC) is a layer with a high content.
  • the underlying layer 8 a mainly composed of Cr formed directly on the surface has good compatibility with the iron-based material, and is more closely adhered to the iron-based material than the layer mainly composed of W or Si. Excellent in properties. Since the WC used for the mixed layer 8b has intermediate hardness and elastic modulus between Cr and DLC, it is possible to suppress the concentration of residual stress in the mixed layer 8b after the hard film 8 is formed. Further, the mixed layer 8b mainly composed of WC and DLC has a gradient composition as described above, so that the mixed layer 8b has a structure in which WC and DLC are physically coupled.
  • the rolling bearing 1 has excellent seizure resistance, wear resistance, and corrosion resistance, and has a long life with little damage to the raceway surface even under severe lubrication.
  • the rolling bearing 1 by forming the hard film 8 having the above-described structure and properties, even when the hard film 8 receives a load such as rolling contact when the bearing is used. The wear and peeling of the hard film 8 can be suppressed. For this reason, the rolling bearing 1 having a long service life with little damage to the raceway surface and the like can be obtained even in a severely lubricated state. Further, in the rolling bearing 1 in which the grease 7 is sealed, if the new metal surface is exposed due to damage to the race rings such as the inner ring 2 and the outer ring 3, the grease is promoted to be deteriorated by the catalytic action.
  • the hard film 8 since the hard film 8 is formed, damage to the inner ring raceway surface 2a, the outer ring raceway surface 3a and the rolling surfaces of the rolling elements 4 due to metal contact can be suppressed. Deterioration can also be suppressed.
  • FIG. 6 is a flowchart for explaining a method of manufacturing the rolling bearing shown in FIGS.
  • FIG. 7 is a schematic diagram for explaining the film forming principle of the UBMS method.
  • FIG. 8 is a schematic diagram illustrating a configuration of an example of the UBMS apparatus.
  • a preparation step (S10) is performed.
  • parts to be a bearing member constituting the rolling bearing 1 are prepared. Examples of the parts include the inner ring 2, the outer ring 3, the rolling element 4, and the seal member 6.
  • a film forming step (S20) is performed.
  • a hard film is formed on the surface of the component prepared in the above step (S10). Details of the film forming step (S20) will be described later.
  • a post-processing step (S30) is performed in which finishing processing, assembly processing, or the like of the part on which the hard film is formed is performed. In this way, the rolling bearing 1 shown in FIGS. 1 to 3 can be obtained.
  • the hard film 8 is obtained by forming the base layer 8a, the mixed layer 8b, and the surface layer 8c in this order on the film formation surface of the component to be the bearing member.
  • the underlayer 8a and the mixed layer 8b are preferably formed using a UBMS apparatus using Ar gas as a sputtering gas.
  • the film forming principle of the UBMS method using the UBMS apparatus will be described with reference to the schematic diagram shown in FIG.
  • the base material 12 is an inner ring 2, an outer ring 3, or a rolling element 4 that is a component to be a bearing member to be formed, but is schematically illustrated as a flat plate shape.
  • the substrate 12 is connected to a bias power source 11.
  • the target 15 is disposed so as to face the substrate 12.
  • the planar shape of the target 15 which is a supply source of the film forming raw material is, for example, a round shape.
  • An inner magnet 14 a and an outer magnet 14 b having different magnetic characteristics in the central portion and the peripheral portion of the round target 15 are disposed below the round target 15.
  • the outer magnet 14b forms a relatively strong magnetic field
  • the inner magnet 14a forms a relatively weak magnetic field.
  • an inner magnet is formed such that a portion 16a of the magnetic force lines 16 generated by the inner magnet 14a and the outer magnet 14b reaches the vicinity of the substrate 12 while forming a high-density plasma 19 from Ar gas near the target 15.
  • a magnetic field is formed by 14a and the outer magnet 14b.
  • a part of the high-density plasma 19 (Ar plasma) generated at the time of sputtering diffuses to the vicinity of the substrate 12 along a part 16a of the lines of magnetic force.
  • the Ar plasma 17 and electrons reach the base material 12 more than the amount of ionized particles 18 derived from the target 15 along the part 16a of the magnetic field lines reaching the vicinity of the base material 12 than during normal sputtering.
  • an ion assist effect is called an ion assist effect.
  • a dense film 13 can be formed on the surface of the substrate 12 by an ion assist effect.
  • a Cr target is used as the target 15.
  • a WC target and a graphite target are used in combination as the target 15.
  • the mixed layer 8b is formed in a continuous or stepwise manner while increasing the power applied to the graphite target serving as the carbon supply source and decreasing the power applied to the WC target.
  • the WC content rate decreases continuously or stepwise from the base layer 8a side to the surface layer 8c side, and the DLC content rate increases continuously or stepwise. The part which became the layer of can be formed.
  • the surface layer 8c may also be formed using a UBMS apparatus using Ar gas as the sputtering gas. More specifically, the following conditions can be used as conditions for forming the surface layer 8c. That is, using a UBMS apparatus, a graphite target and a hydrocarbon gas are used in combination as a carbon supply source. The ratio of the introduction amount of the hydrocarbon-based gas to the introduction amount 100 of the Ar gas into the UBMS apparatus is set to 1 or more and 10 or less. The degree of vacuum in the UBMS device is set to 0.2 Pa or more and 0.8 Pa or less. It is preferable to form the surface layer 8c which is a DLC film by depositing particulate carbon generated by sputtering from the carbon supply source on the mixed layer 8b using such conditions. The conditions described above will be described below.
  • the hardness and elastic modulus of the DLC film can be adjusted by using a graphite target and a hydrocarbon-based gas in combination as a carbon supply source.
  • Gases such as methane, acetylene, and benzene can be used as the hydrocarbon gas. Although it does not specifically limit as hydrocarbon type gas, It is preferable to use methane gas from the point of cost and handleability.
  • the ratio of the introduction amount of the hydrocarbon-based gas is 1 to 10 (volume part) with respect to 100 introduction amount (volume part) of Ar gas into the UBMS apparatus (specifically, in the film forming chamber of the UBMS apparatus).
  • the degree of vacuum in the film forming chamber is preferably 0.2 Pa or more and 0.8 Pa or less as described above. More preferably, the degree of vacuum is 0.25 Pa or more and 0.8 Pa or less.
  • the degree of vacuum is less than 0.2 Pa, since the amount of Ar gas in the film formation chamber is small, Ar plasma is not generated and the surface layer 8c may not be formed. Further, when the degree of vacuum in the film forming chamber is higher than 0.8 Pa, reverse sputtering phenomenon tends to occur, and the wear resistance of the surface layer 8c may be deteriorated.
  • the method for manufacturing the rolling bearing 1 includes a step of preparing an inner ring, an outer ring, and a rolling element (S10), and a step of forming a hard film (film formation step (S20)).
  • the hard film 8 is formed on at least one surface selected from the group consisting of the inner ring 2, the outer ring 3, and the rolling element 4.
  • an unbalanced magnetron sputtering (UBMS) apparatus using argon gas as the sputtering gas is used.
  • a graphite target and a hydrocarbon gas are used in combination as a carbon supply source, and the ratio of the introduction amount of the hydrocarbon gas to the introduction amount 100 of argon gas into the apparatus is 1 or more. 10 or less.
  • the surface layer 8c is formed by depositing carbon atoms generated from the carbon supply source on the mixed layer 8b. If it does in this way, the rolling bearing 1 excellent in durability which concerns on this embodiment can be obtained.
  • the surface layer 8c formed by the step (S20) has an inclined layer portion 8d whose hardness increases continuously or stepwise from the mixed layer 8b side on the side adjacent to the mixed layer 8b. You may have.
  • the bias voltage applied to at least one selected from the group consisting of the inner ring 2, the outer ring 3, and the rolling element 4 including the surface is increased continuously or stepwise.
  • the inclined layer portion 8d is formed. In this way, the inclined layer portion 8d can be easily formed.
  • the base layer 8a and the mixed layer 8b are formed using the UBMS apparatus using argon gas as the sputtering gas as described above. Also good.
  • the mixed layer is continuously or stepwise increased while increasing the sputtering power applied to the graphite target serving as the carbon supply source and lowering the power applied to the tungsten carbide target. 8b may be formed. In this way, the composition of WC and DLC in the mixed layer 8b can be changed in the thickness direction.
  • the method for manufacturing a rolling bearing includes a step of forming a nitride layer by performing nitriding treatment on the surface on which the hard film 8 is formed before the step of forming the hard film (S20). Also good.
  • the nitriding treatment may be a plasma nitriding treatment.
  • the surface roughness Ra of the surface on which the hard film 8 is formed in the step of forming the hard film (S20) may be 0.05 ⁇ m or less. In this case, the hard film 8 in which the film thickness variation is suppressed can be formed.
  • the above rolling bearing manufacturing method may further include a step of enclosing grease around the rolling element 4.
  • the rolling bearing 1 in which the grease 7 is enclosed can be obtained.
  • Example 2 In order to confirm the effect of the hard film formed on the rolling bearing according to the present embodiment, a hard film was formed on a predetermined substrate, and the physical properties of the hard film were evaluated. The peel resistance was evaluated by a friction and wear test using a reciprocating sliding tester. This will be specifically described below.
  • FIG. 8 is a schematic diagram of a UBMS apparatus.
  • the UBMS apparatus instantaneously vaporizes and ionizes the AIP evaporation source material 22a using the vacuum arc discharge to the base material 21 arranged on the disk 20, and based on this. It has an AIP function of depositing on the material 21 to form a film. Further, the UBMS apparatus forms a non-equilibrium magnetic field between the target 22b, which is a sputter evaporation source material, and the base material 21, and increases the plasma density near the base material 21 by the magnetic field to increase the ion assist effect. (See FIG.
  • the sputtering power applied to the Cr target and WC target is adjusted by the UBMS method, the composition ratio of Cr and WC is tilted, and a Cr / WC graded layer with a lot of Cr on the substrate side and a lot of WC on the surface side is formed. did.
  • the formation conditions of the mixed layer are basically the same as the formation conditions of the underlayer except for the sputtering power described above.
  • Sample No. Regarding 1 to 7, the above-described underlayer and mixed layer were formed under the same conditions.
  • Surface layer formation conditions Sample No. For each of 1 to 7, a surface layer was formed under the conditions shown in Table 1.
  • Manufacturing method of each sample The substrate shown in Table 1 described later was ultrasonically cleaned with acetone and then dried.
  • the substrate was attached to a UBMS apparatus, and an underlayer and a mixed layer were formed under the above-described formation conditions.
  • a DLC film which is a surface layer, was formed on the film formation conditions shown in Table 1 to obtain a test piece having a hard film. Note that “degree of vacuum” in each table is the degree of vacuum in the film forming chamber in the above apparatus.
  • the reciprocating sliding test machine shown in FIG. 9 includes a pedestal 32 that holds a sample on which a base material 21 and a hard film 8 are formed, a load cell 27 and an acceleration sensor 28 installed on the pedestal 32, and a hard film 8 of the sample.
  • the holder 26 can apply a load from the direction indicated by the arrow 30.
  • the test was performed without lubrication. In the test, the load was increased, and the load when the friction coefficient increased due to the peeling of the hard film 8 was defined as the limit load. Specific test conditions are shown below.
  • Lubrication No lubrication Ball: 3/8 inch, silicon nitride ball Load: 30-80N Load increase speed: 10 N / min Vibration frequency: 60Hz Amplitude: 2mm
  • Indentation hardness measurement For the hard film 8 of each sample, the indentation hardness was measured using a nanoindenter (G200) manufactured by Agilent Technologies. In addition, the measured value has shown the average value of the depth (location where hardness is stabilized) which is not influenced by surface roughness, and measured 10 places for each sample.
  • Table 1 shows the sample conditions and test results.
  • the methane gas introduction ratio is the ratio of the methane gas introduction amount to the argon gas introduction amount 100.
  • Sliding surfaces and rolling surfaces for which application of DLC is considered are often in a severely lubricated state such as poor lubrication or high sliding speed.
  • DLC is formed on the inner and outer ring raceway surfaces and the rolling surfaces of the rolling elements. Therefore, even when operated in a severely lubricated state, the rolling bearing has excellent peeling resistance, and The characteristics can be demonstrated. For this reason, the rolling bearing is excellent in seizure resistance, wear resistance, and corrosion resistance. Therefore, the rolling bearing can be applied to various uses including use in severe lubrication.

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  • Engineering & Computer Science (AREA)
  • General Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Chemical & Material Sciences (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Materials Engineering (AREA)
  • Metallurgy (AREA)
  • Organic Chemistry (AREA)
  • Manufacturing & Machinery (AREA)
  • Rolling Contact Bearings (AREA)

Abstract

Palier à roulement qui présente une excellente durabilité. Ce palier à roulement (1) est pourvu d'une bague intérieure (2), d'une bague extérieure (3), d'une pluralité de corps roulants (4) et d'un film dur (8). Le film dur (8) est formé sur la surface d'au moins un composant sélectionné dans le groupe constitué de la bague intérieure (2), de la bague extérieure (3) et des corps roulants (4). La bague intérieure (2), la bague extérieure (3) et la pluralité de corps roulants (4) sont formés à partir d'un matériau à base de fer. Le film dur (8) comprend une couche de base (8a), une couche mixte (8b) et une couche de surface (8c). La couche de base (8a) est principalement composée de Cr, et est formée directement sur la surface précitée. La couche mixte (8b) est principalement composée de WC et de DLC, et est formée sur la couche de base (8a). La couche de surface (8c) est principalement composée de DLC, et est formée sur la couche mixte (8b). La couche mixte (8b) est conçue de telle sorte que la teneur en WC dans la couche mixte (8b) diminue et que la teneur en DLC dans la couche mixte augmente en continu ou par étapes depuis le côté couche de base (8a) vers le côté couche de surface (8c).
PCT/JP2018/008623 2017-03-07 2018-03-06 Palier à roulement et son procédé de fabrication WO2018164139A1 (fr)

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Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20220010836A1 (en) * 2019-04-05 2022-01-13 Ntn Corporation Self-aligning roller bearing
US11542985B2 (en) 2018-09-26 2023-01-03 Ntn Corporation Rolling bearing and wind power generation rotor shaft support device

Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2011122662A1 (fr) * 2010-03-30 2011-10-06 Ntn株式会社 Palier anti-friction

Patent Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2011122662A1 (fr) * 2010-03-30 2011-10-06 Ntn株式会社 Palier anti-friction

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US11542985B2 (en) 2018-09-26 2023-01-03 Ntn Corporation Rolling bearing and wind power generation rotor shaft support device
US20220010836A1 (en) * 2019-04-05 2022-01-13 Ntn Corporation Self-aligning roller bearing
US11773901B2 (en) * 2019-04-05 2023-10-03 Ntn Corporation Self-aligning roller bearing

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