JP6531905B2 - Friction part structure and method of forming friction surface - Google Patents

Description

  The present invention relates to a friction part structure and a method of forming a friction surface.

  In mechanical parts used in various fields, friction parts exist in movable parts such as rotation, extension and contraction, and bending. Specific examples thereof include a motor and a pump provided with a drive shaft, a cylinder provided with a rod, and an artificial joint imitating a living joint such as a knee joint and a hip joint.

  And conventionally, from the viewpoint of kinetic efficiency mainly, the structure of the friction part with as little friction resistance as possible is proposed (for example, refer to patent documents 1.).

  According to the mechanical component provided with such a friction part, the movable part can be moved smoothly, and furthermore, the amount of wear can be reduced and generation of wear powder can be suppressed as much as possible.

Japanese Patent Publication No. 2013-531118 gazette

  By the way, focusing on, for example, an artificial joint among the above-mentioned mechanical parts, an artificial joint is implanted in the body by surgery and functions as a substitute for the joint. Exchange is not easy.

  Therefore, it is an important factor in the construction of the artificial joint to provide a friction part having a low friction resistance and a low generation amount of wear powder, and in recent years, one capable of maintaining a low friction resistance state has been developed for many years .

  However, there is a problem that fine wear powder is generated from the friction part having a small friction resistance as compared with the size of the wear powder generated in the conventional friction part.

  Specifically, when attrition powder of about 0.1 μm to 1 μm is generated and dissipated around the artificial joint, it becomes mainly a phagocytosing target of macrophages, causing an immune reaction in the living body, and an inflammatory reaction etc. There was a possibility that it might occur.

  Therefore, there is a need for an artificial joint provided with a friction portion that has three contradictory features of low friction resistance, suppression of miniaturization of wear powder, and suppression of generation of wear powder.

  In addition, in the case of mechanical parts in general having friction parts as well as artificial joints, the dissipation of fine wear powder may cause an undesirable phenomenon, such as causing wear at an unexpected part.

  The present invention has been made in view of such circumstances, and while realizing low friction resistance, it is possible to suppress the generation of fine wear powder, and also suppress the generation amount of wear powder itself. To provide a friction part structure that can be

  The present invention also provides an artificial joint having the same friction portion structure, a method of forming a friction surface that constitutes the friction portion structure, and the like.

  In order to solve the above-mentioned conventional problems, in the friction portion structure according to the present invention, (1) a pair of members formed between a pair of members with different hardness, which slide relative to each other in the presence of lubricating fluid In the structure of the friction portion provided with a friction surface, the friction surface having a relatively high hardness among the pair of friction surfaces is a transfer film on which a transfer film is formed by contact with a friction surface having a relatively low hardness. And at least one of a groove shape and a hole shape in which the width gradually narrows from the surface side to the inside of the high hardness friction surface, and the transfer film formation portion is formed at the time of pressure contact of the pair of friction surfaces. And a concave portion having a capacity for allowing the lubricating fluid present on the surface to flow in and be stored to make the surface substantially non-lubricating liquid, and the surface of the transfer film forming portion is the pair of friction surfaces Of the transfer film forming portion by the lubricating fluid that has spilled out of the recess along with the Further comprising a transcribing film peeling conducive means to promote the release of the transfer adhesive layer formed on the surface was that characterized.

The friction portion structure according to the present invention is also characterized by the following points.
(2) The transfer film separation promoting means is a surface structure of the transfer film forming portion having an arithmetic average roughness (Ra) of 1 nm to 3 nm.
(3) The surface structure is one obtained by polishing with a dispersion formed by dispersing diamond particles having a primary particle diameter of 2 nm to 5 nm in a predetermined solvent.
(4) The dispersion is obtained by dispersing a crushed material having a particle size distribution of 2 nm to 20 nm obtained by crushing a coagulated body formed by aggregating diamond particles having a primary particle diameter of 2 nm to 5 nm. is being done.
(5) The high-hardness friction surface has an orange peel structure in which a plurality of pits functioning as the concave portion are formed on a surface of a predetermined curvature functioning as the transfer film forming portion.
(6) The high-hardness friction surface has a structure in which a plurality of grooves functioning as the concave portion are formed on the surface having a predetermined curvature functioning as the transfer film forming portion.
(7) The plurality of grooves are formed in a lattice shape on the surface, and the edges of adjacent grooves parallel to each other are partially overlapped to form a substantially sine wave in a cross sectional view orthogonal to the extending direction of the grooves. Waveform structure.

  Moreover, in the artificial joint which concerns on this invention, we decided to provide the friction part structure in any one of (8) said (1)-(7).

  In the present invention, (9) diamond particles having a primary particle diameter of 2 nm to 5 nm in order to form a transfer film peeling promoting means in the friction portion structure according to any one of the above (1) to (7). A dispersion dispersed in a predetermined solvent was used as an abrasive.

  In the use of (9), (10) the dispersion may be 2 nm to 5 nm obtained by breaking up a coagulated body formed by aggregating diamond particles having a primary particle diameter of 2 nm to 5 nm. It is also characterized in that crushed materials having a particle size distribution of 20 nm are dispersed.

  In the method of forming a friction surface according to the present invention, (11) a pair of friction surfaces which are formed between a pair of members of different hardness and which slide relative to each other in the presence of a lubricating liquid are provided. A method of forming a friction surface having a relatively high hardness of the pair of friction surfaces in a friction portion, the abrasive grain having a primary particle diameter of 1 μm to 5 μm in a region forming the friction surface on the high hardness side Polishing with the first abrasive liquid in which the particles are dispersed, to make the same region have a surface with an arithmetic average roughness (Ra) of 10 nm to 20 nm, and the surface formed in the lapping step from the same surface side The concave portion forming step of forming a concave portion having at least one of a groove shape and a hole shape whose width gradually narrows toward the inner side, and at least a region other than the concave portion in the surface formed in the concave portion forming step Predetermined diamond particles with primary particle size By grinding with a second abrasive fluid, which is a dispersion dispersed in a medium, and setting the area other than this concave part to an arithmetic average roughness (Ra) of 1 nm to 3 nm, with the friction surface on the low hardness side And polishing the surface as a high hardness side friction surface having a surface structure as transfer film peeling promoting means for promoting peeling of the transfer film transferred to a region other than the concave portion by pressure contact sliding. And

  Further, in the method of forming a friction surface according to the present embodiment, (12) a pair of friction surfaces which are formed between a pair of members having different hardness and which slide relative to each other in the presence of a lubricating liquid are provided. A method of forming a friction surface on the relatively hard side of the pair of friction surfaces in the friction portion, wherein the region forming the friction surface on the high hardness side has a primary particle diameter of 1 μm to 5 μm A lapping step of polishing with the first abrasive fluid in which the particles are dispersed to make the same region a surface with an arithmetic average roughness (Ra) of 10 nm to 20 nm, and the first abrasive fluid or primary particle diameter of 2 nm to A second abrasive fluid, which is a dispersion of abrasive particles of 5 nm dispersed in a predetermined solvent, is linearly focused on the surface formed in the lapping step while being ejected linearly and scanned vertically and horizontally. When forming a groove, and forming a parallel groove adjacent to the formed groove, a new formation is made. The edge of the groove is scanned while partially overlapping with the edge of the formed groove to form a substantially sinusoidal wave structure in a cross sectional view orthogonal to the scanning direction of both grooves, and the arithmetic mean of the scanned area By setting the roughness (Ra) to 1 nm to 3 nm by the collision of the first or second abrasive liquid, the transfer transferred to the region near the top of the corrugated structure by press-contact sliding with the low hardness side friction surface A concave portion forming step of forming a friction surface on the high hardness side on which a surface structure is formed as a transfer film peeling promoting means for promoting the peeling of the deposited film.

  Furthermore, in the method of forming a friction surface according to the above (11) or (12), (13) the dispersion dissolves a coagulated body formed by aggregating diamond particles having a primary particle diameter of 2 nm to 5 nm. It is also characterized in that a crushed material having a particle size distribution of 2 nm to 20 nm obtained by crushing is dispersed as an abrasive.

  According to the friction portion structure according to the present invention, the structure of the friction portion includes a pair of friction surfaces which are formed between a pair of members having different hardness and relatively slide in contact with each other in the presence of the lubricating liquid. The relatively high hardness friction surface of the pair of friction surfaces is a transfer film forming portion on which the adhesion film is formed by contact with the relatively low hardness friction surface, and the high hardness friction surface A groove-like and / or hole-like shape in which the width gradually narrows from the surface side to the inside of the surface, and the lubricating fluid present on the surface of the transfer film forming portion flows in during pressure contact of the pair of friction surfaces; And a concave portion having a volume capable of containing the surface and making the surface substantially non-lubricating liquid, and the surface of the transfer film forming portion is closer to the concave portion as the pair of friction surfaces press-contact and slide. Peeling of the transfer film formed on the surface of the transfer film forming portion by the lubricating fluid overflowed As the transfer film peeling promoting means is promoted, it is possible to suppress the generation of fine wear powder while realizing low friction resistance, and to suppress the generation amount of the wear powder itself. It is possible to provide a friction part structure that can be made.

  In addition, if the transfer film separation promoting means is a surface structure of the transfer film forming portion having an arithmetic average roughness (Ra) of 1 nm to 3 nm, the transfer film can be formed steadily. Also, the transfer film can be easily peeled off by the lubricating fluid overflowing from the recess.

  In addition, if the surface structure is polished with a dispersion formed by dispersing diamond particles having a primary particle diameter of 2 nm to 5 nm in a predetermined solvent, the surface structure can be formed accurately and easily. can do.

  In the dispersion, a crushed material having a particle size distribution of 2 nm to 20 nm obtained by crushing a coagulated body formed by aggregating diamond particles having a primary particle diameter of 2 nm to 5 nm is dispersed. Therefore, the polishing efficiency can be improved, and the surface structure can be formed more easily.

  In addition, if the high-hardness friction surface has an orange peel structure in which a plurality of pits functioning as the recess is formed on a surface of a predetermined curvature functioning as the transfer film forming portion, it is other than a pit The portion of the surface of the above can be made to function as transfer film peeling promoting means to make it possible to steadily increase the size of the wear powder.

  In addition, if the high-hardness friction surface has a structure in which a plurality of grooves functioning as the recess is formed on the surface having a predetermined curvature functioning as the transfer film forming portion, a surface other than the grooves Can be made to function steadily as a transfer film peeling promoting means to steadily increase the size of the wear powder.

  Further, the plurality of grooves are formed in a lattice shape on the surface, and edges of adjacent grooves parallel to each other are partially overlapped to form a substantially sinusoidal wave in a cross-sectional view orthogonal to the extending direction of the grooves. With the wave-like structure, the vicinity of the top of the wave-like structure can be made to function as transfer film peeling promoting means, and the wear powder can be made large steadily.

  Further, according to the artificial joint according to the present invention, generation of fine wear powder can be suppressed while realizing low friction resistance, by using the artificial joint provided with the above-mentioned friction part structure, In addition, it is possible to provide the artificial joint provided with the friction portion structure capable of suppressing the generation amount of the wear powder itself.

  In addition, in order to form the transfer film separation promoting means in the above-mentioned friction part structure, a dispersion formed by dispersing diamond particles having a primary particle diameter of 2 nm to 5 nm in a predetermined solvent is used as an abrasive. The transfer film peeling promoting means can be easily formed.

  In addition, in the use, the dispersion has a particle size distribution of 2 nm to 20 nm obtained by breaking up a coagulated body formed by aggregating the diamond particles having the primary particle diameter of 2 nm to 5 nm. With the crushed material dispersed, the polishing efficiency can be improved, and the transfer film peeling promoting means can be formed more easily.

  Further, according to the method of forming a friction surface according to the present invention, the friction provided with a pair of friction surfaces which are formed between a pair of members having different hardness and which relatively slide in contact with each other in the presence of a lubricating fluid. A method of forming a friction surface having a relatively high hardness side among the pair of friction surfaces in a part, wherein an abrasive grain having a primary particle diameter of 1 μm to 5 μm is formed in a region forming the friction surface on the high hardness side A lapping process for polishing with the dispersed first abrasive liquid to make the same area have a surface with an arithmetic average roughness (Ra) of 10 nm to 20 nm, and a surface formed in the lapping process from the same surface side. Forming at least one of a groove shape and a hole shape in which the width gradually narrows, and at least a region other than the recess in the surface formed in the recess formation step, Predetermined solvent for diamond particles having a particle diameter By polishing with a second abrasive liquid, which is a dispersion dispersed in the above, and setting the area other than the concave portion to an arithmetic mean roughness (Ra) of 1 nm to 3 nm, the pressure contact slide with the friction surface on the low hardness side The polishing process has a high hardness side friction surface on which a surface structure is formed as a transfer film peeling promoting means for promoting peeling of the transfer film transferred to the area other than the concave portion by movement. To form a friction surface capable of constituting a friction portion structure which can suppress the generation of fine wear powder while realizing low friction resistance, and can also suppress the generation amount of wear powder itself. be able to.

  Further, according to the method of forming a friction surface according to the present invention, the friction provided with a pair of friction surfaces which are formed between a pair of members having different hardness and which relatively slide in contact with each other in the presence of a lubricating fluid. A method of forming a friction surface having a relatively high hardness side among the pair of friction surfaces in a part, wherein an abrasive grain having a primary particle diameter of 1 μm to 5 μm is formed in a region forming the friction surface on the high hardness side A lapping step of polishing with the dispersed first abrasive liquid to make the same area a surface with an arithmetic average roughness (Ra) of 10 nm to 20 nm, and the first abrasive liquid or primary particle diameter of 2 nm to 5 nm A second abrasive liquid, which is a dispersion in which abrasive grains are dispersed in a predetermined solvent, is jetted while linearly converging on the surface formed in the lapping step and scanned longitudinally and laterally to form a grid-like groove. When forming a parallel groove adjacent to the groove being formed, the newly formed groove Part is overlapped with the edge of the formed groove and scanning is performed to form a substantially sinusoidal waveform structure in a cross sectional view orthogonal to the scanning direction of both grooves, and the arithmetic average roughness (Ra of the scanned area) Of 1 nm to 3 nm by the collision of the first or second abrasive fluid, the peeling of the transferred film transferred to the region near the top of the corrugated structure by pressure contact sliding with the low hardness side friction surface Forming a concave surface on the high hardness side on which the surface structure is formed as a transfer film peeling promoting means to promote the formation of fine particles, so that fine abrasion powder can be realized while realizing low frictional resistance. It is possible to form a friction surface capable of constituting the friction portion structure which can suppress the generation of the friction and can also suppress the generation amount of the wear powder itself.

  In the dispersion, a crushed material having a particle size distribution of 2 nm to 20 nm obtained by crushing a coagulated body formed by aggregating the diamond particles having a primary particle diameter of 2 nm to 5 nm is an abrasive grain If it is dispersed as, the polishing efficiency can be improved, and the transfer film peeling promoting means can be formed more easily.

It is explanatory drawing which showed the concept of the friction part structure which concerns on this embodiment. It is explanatory drawing which showed the concept of the friction part structure which concerns on this embodiment. It is the model which showed the surface state of the orange peel structure. It is a schematic diagram showing the surface structure which has a slot. It is an explanatory view showing composition of a micro slurry erosion device. It is an explanatory view showing a formation process of waveform structure. It is explanatory drawing which showed the formation process of the friction surface. It is the particle size distribution measurement data of the water dispersion of nano diamond particles. It is the graph which showed the verification test result of the amount of wear. It is the graph which showed the particle size distribution measurement result of abrasion powder. It is an explanatory view showing various test results.

  The present invention relates to the structure of a friction portion provided with a pair of friction surfaces which are formed between a pair of members of different hardness and which slide relative to each other in the presence of a lubricating fluid.

  Here, the friction portion is a sliding portion of movable parts in various mechanical parts, and the mechanical parts themselves are not particularly limited.

  The components of the lubricating fluid are not particularly limited, and it is possible to use oil-based lubricating fluid, which is used for general mechanical parts, as well as aqueous lubricating fluid, and bodily fluid (joint fluid) that functions as a lubricating fluid in living organisms. ) Is a concept that also includes.

  And, as a feature of the friction portion structure according to the present embodiment, among the pair of friction surfaces, the relatively high hardness friction surface forms a transfer film by contact with the relatively low hardness friction surface. And at least one of a groove shape and a hole shape in which the width gradually narrows from the surface side to the inside of the high hardness friction surface, and the pressure is transferred at the time of pressure contact of the pair of friction surfaces. The surface of the transfer film forming part is provided with a recess having a capacity to allow the lubricating liquid present on the surface of the film forming part to flow in and be stored, and to make the surface substantially non-lubricating liquid state; Transfer film peeling promoting means is provided for promoting peeling of the transfer film formed on the surface of the transfer film forming portion by the lubricating liquid overflowing from the recess along with the pressure contact sliding of the pair of friction surfaces. And

  The concept of the friction portion structure according to the present embodiment having such a configuration will be described with reference to FIGS. 1 and 2 in order to provide an understanding of the invention. 1 and 2 are conceptual views showing the state of the friction surface. In the conceptual diagrams shown in FIGS. 1 and 2, the size of the pit, the thickness, the shape, etc. of the transfer film are not necessarily accurate.

  As shown in FIG. 1A, the high hardness surface 13 and the low hardness surface 14 are formed in the friction portion 12 formed between the high hardness member 10 and the low hardness member 11 and formed between a pair of members with different hardness. The lubricating fluid 15 intervenes between the friction surfaces, that is, between the friction surfaces.

  Further, on the high hardness surface 13, fine recesses 16 are formed in advance.

  In such a state, when a load is gradually applied between the two members and the space between the friction surfaces is narrowed, most of the lubricating fluid 15 is discharged out of the friction portion 12 as shown in FIG. 1 (b). Ru. Further, the lubricating fluid is also filled in the recess 16.

  Here, when the friction portion 12 is further enlarged, as shown in FIG. 1C, a very small amount of lubricating fluid 15 still exists between the friction surfaces in a state where a liquid film is formed.

  Next, when a sufficient load is applied between the two members, as shown in FIG. 1 (d), a very small amount of lubricating fluid 15 existing between the friction surfaces is already full of lubricating fluid 15. It is accommodated while being compressed in the recess 16, the lubricating liquid 15 is not present between the friction surfaces, and the high hardness surface 13 and the low hardness surface 14 are in direct contact with each other.

  When sliding occurs due to relative movement between the high hardness member 10 and the low hardness member 11 in such a state, as shown in FIG. 2A, the low hardness portion of the high hardness surface 13 other than the recess 16 A part of the member 11 is transferred to form the transfer film 17. That is, the portion other than the concave portion 16 of the high hardness surface 13 functions as the transfer film forming portion 18.

  When the transfer film 17 is formed as described above, the transfer film 17 and the low hardness member 11 substantially contact each other, and the material of the transfer film 17 is the same as the material of the low hardness member 11. As compared with the frictional resistance between the high hardness member 10 and the low hardness member 11, a low frictional resistance is exhibited to promote smooth sliding.

  Further, as shown in FIG. 2B, the transfer film 17 formed on the transfer film forming portion 18 is gradually repeated by relative motion between the high hardness member 10 and the low hardness member 11. Thicken.

  Along with this, the position of the friction surface is also gradually separated from the high hardness surface 13, and the depth of the recess 16 becomes relatively deep. With the separation movement of the friction surface, the pressure of the lubricating liquid contained in the recess 16 is released, and the liquid level of the lubricating liquid 15 is higher than the level of the interface between the high hardness surface 13 and the transfer film 17. It becomes a high position.

  Also, between the transfer film 17 and the low hardness surface 14, fine friction powder (hereinafter also referred to as fine friction powder 19) is also generated along with the sliding. As mentioned above, this fine friction powder 19 causes an unexpected reduction in area in a general mechanical component having a movable part, and it is a target for phagocytosis of macrophages in an artificial joint replaced in vivo. And cause an inflammatory reaction.

  Therefore, as a feature of the friction portion structure according to the present embodiment, means is provided for intentionally promoting the peeling of the transfer film 17 which contributes to the reduction of the frictional resistance.

  That is, the transfer film peeling promoting means is provided on the surface of the transfer film forming portion 18, and as shown in FIG. 2C, the peeling start portion 20 of the transfer film 17 at the periphery of the recess 16 or the like. Formation is prompted.

  Then, the lubricating liquid 15 overflowing from the concave portion 16 infiltrates between the high hardness surface 13 and the transfer film 17 from the peeling start portion 20 which has become incised by, for example, capillary phenomenon, and functions as a peeling liquid. The transfer film 17 is gradually peeled off.

  The separated transfer film 17 is enlarged while involving the fine friction powder 19 so that the large scraps of the eraser are combined with each other and the large wear powder 30 is formed (FIG. 2 (d)). reference.).

  Therefore, the enlargement of the wear powder is promoted and the fine friction powder 19 is not dissipated, thereby reducing the possibility of unexpected abrasion in general mechanical parts or the like, inflammation in the living body derived from the artificial joint, etc. be able to.

  Moreover, peeling does not occur in all of the transfer film 17, and the contact area between the transfer film 17 and the low hardness surface 14 is determined when the peeling of the transfer film is not promoted or when the recess 16 does not exist. In comparison with this, the amount of generation of wear powder can be suppressed while realizing low frictional resistance.

  As described above, according to the friction portion structure according to the present embodiment, it is possible to realize the friction portion having the three contradictory characteristics of low friction resistance, suppression of miniaturization of wear powder, and suppression of generation amount of wear powder. Can.

  However, when the high hardness surface 13 and the low hardness surface 14 are in pressure contact with each other, the recess 16 allows the lubricating liquid present on the surface of the transfer film forming portion to flow in and be accommodated, thereby making the surface substantially non-lubricating liquid You need to have a capacity.

  It is desirable that a plurality of such concave portions 16 be provided on the high hardness surface 13. More specifically, when the area of the high hardness surface 13 in planar view not considering unevenness is 100%, in the planar view It is preferable to form the recess 16 so that the area of the region not functioning as the transfer film forming portion 18 is 1% to 50%, more preferably 1% to 30%.

  In addition, the recess 16 may be at least one of a groove shape and a hole shape whose width gradually narrows from the surface side to the inside of the friction surface.

  When the recess 16 is in the form of a hole (pit), it is desirable that the opening diameter be 10 nm to 100 nm and the depth be 35 nm to 65 nm.

  Moreover, when the recessed part 16 is groove shape, it is desirable for the width | variety of a groove | channel to be 10 nm-5 mm, and to be 35 nm-200 nm in depth. More specifically, in the case of a fine lattice structure as shown in FIG. 4A described later, the groove width is 10 nm to 100 nm, the depth is 35 nm to 65 nm, and the groove interval is 0.1 mm to 1.0 mm. The width of the groove may be 0.5 mm to 5 mm and the depth may be 35 nm to 200 nm in the case of a relatively coarse lattice structure as shown in FIG. In the case where the recess 16 is a groove, the possibility that the pressing of the lubricating fluid 15 into the recess 16 described with reference to FIG. 2 does not occur (there is a space for pressure relief) can not be denied either. The interface of the lubricating fluid 15 contained in the recess 16 is considered to be in the vicinity of the interface between the high hardness surface 13 and the transfer film 17 due to the surface tension of the lubricating fluid 15, etc. Spilling out of the lubricating fluid 15 is promoted.

  Further, the substantially non-lubricated liquid state does not mean a state in which no composition component of the lubricating liquid adheres to the surface of the transfer film forming portion 18, and the lubricating function of the lubricating liquid 15 It means a state of being depleted to such an extent that it can not be fully exerted.

  By the way, the transfer film peeling promoting means provided on the surface of the transfer film forming portion 18 is not particularly limited as long as it is means for promoting the peeling of the transfer film 17 by the lubricating liquid 15 overflowing from the recess 16 .

  If a more specific example of such a transfer film peeling promoting means is daringly shown, it is an edge shape of the recess 16 and is smooth connected from the recess side wall surface expanding upward and the transfer film forming portion 18 Curved surface shape can be mentioned.

  By providing such an edge shape, the transfer film can be formed to be thin gradually along the depression direction of the recess, and the end of the transfer film is caused to break up along with the sliding in the friction portion 12. Can promote the peeling.

  Further, as a further example, the transfer film separation promoting means may include the surface structure of the transfer film forming portion 18 having an arithmetic average roughness (Ra) of 1 nm to 3 nm.

  For example, when the arithmetic mean roughness of this surface structure is less than 1 nm, the cohesion wear increases and the amount of friction powder is increased, which is not preferable. Moreover, even if it exceeds 3 nm, it is not preferable because the machinability wear (abrasive wear) increases and the amount of friction powder increases.

  By setting the arithmetic average roughness of the surface structure to 1 nm or more and 3 nm or less, it is possible to appropriately reduce the biting depth of fine unevenness on the interface between the transfer film forming portion 18 and the transfer film 17 Peeling of the transfer film 17 from the transfer film forming unit 18 can be promoted at the time of penetration of the lubricating liquid 15 from the peeling start unit 20.

  Further, in forming such a surface structure of the transfer film forming portion 18, it is preferable to use an abrasive liquid in which fine abrasive particles of about 2 nm to 5 μm are dispersed in a solvent.

  Specifically, an abrasive liquid in which diamond particles or alumina particles having a particle diameter of about 1 μm to 5 μm are dispersed as abrasive particles, or diamond particles or alumina particles having a particle diameter of about 2 nm to 5 nm are dispersed as abrasive particles. Abrasive fluid can be employed. For example, an abrasive liquid containing abrasive grains of about 1 μm to 5 μm forms a surface structure of the transfer film forming portion 18 having an arithmetic average roughness (Ra) of 1 nm to 3 nm by being provided to a microslurry erosion device 40 described later. can do.

  In addition, an abrasive liquid containing abrasive particles of about 2 nm to 5 nm, more preferably, an aggregate having a secondary particle diameter of 2 nm to 20 nm formed by aggregating diamond particles having a primary particle diameter of 2 nm to 5 nm A dispersion dispersed in a solvent can form the above-described surface structure by being subjected to a polishing operation. In addition, this grinding | polishing is grinding | polishing corresponding to the below-mentioned polishing process, and mentions a polishing process later.

  A clot with such properties can be obtained, for example, by a detonation method in which an oxygen-deficient explosive is detonated. For details, it is entrusted to International Publication WO2009 / 060613, International Publication WO2007 / 001031, etc., but the explosive composition in a predetermined mixing ratio is detonated in the explosion chamber to recover and purify the explosive product. It can be obtained by doing. In addition, the obtained coagulated body may be subjected to a heat treatment in a hydrogen atmosphere, if necessary, to a hydrogenated coagulated body to facilitate disintegration.

  In addition, in the dispersion used as the abrasive fluid, it is possible that primary particles may be mixed as well as coagulated bodies which are secondary particles, and coagulated bodies which are easily disintegrated (for example, The hydrogenated coagulated substance) may be subjected to a bead milling method or the like in a predetermined solvent and subjected to wet dispersion treatment to increase the primary particle ratio. Further, if necessary, further dispersion processing may be performed by ultrasonic treatment or the like. In the dispersion obtained by the dispersion treatment method, fine particles having a 50% particle size of 50 nm or less, preferably 30 nm or less, more preferably 2 nm to 20 nm in volume average particle diameter in particle size distribution measurement by dynamic scattering method It is used as a formulated dispersion.

  The solvent used for the dispersion is not particularly limited as long as the diamond particles obtained as described above can be dispersed uniformly, but a polar solvent is preferable. Examples of polar solvents include protic polar solvents and aprotic polar solvents. Specific examples of the protic polar solvent which can be used include water, methanol, ethanol, 1-propanol, 2-propanol, 1-butanol, formic acid, acetic acid, 2-methoxyethanol and the like, preferably a C3 to C6 alcohol or C1-C3 alkoxy substituted C1-C4 alcohol etc. are preferable. Specific examples of aprotic polar solvents that can be used include ether solvents such as tetrahydrofuran (THF), methyl tert-butyl ether, 1,4-dioxane, diethylene glycol dimethyl ether, ethylene glycol dimethyl ether, 1,3-dioxolane, 2-methyltetrahydrofuran and the like Amide solvents such as N, N-dimethylformamide (DMF) or N, N-dimethylacetamide (DMAc); ketone solvents such as acetone or N-methyl-2-pyrrolidone; nitrile solvents such as acetonitrile or propionitrile; dimethyl Sulfoxide (DMSO), sulfolane, 1,3-dimethyl-2-imidazolidinone (DMI), acetone, acetonitrile, N, N-dimethylformamide, dimethylsulfoxide, N-methane -2-pyrrolidone is preferred. These solvents may be used alone or in combination of any combination. Although the amount of the solvent used is not particularly limited, it is preferably used so that the concentration of diamond is about 0.1% by weight to 20% by weight.

  The high-hardness surface 13 and the low-hardness surface 14 are surfaces that constitute the friction portion 12 and thus need to have surface shapes that can exhibit functions according to the constituent members provided with the friction portion 12. It does not need to be a horizontal surface, and may be a surface having a predetermined curvature. That is, it may be a complex surface shape such as a friction surface of a joint in a living body.

  Further, the high hardness surface 13 is a so-called orange in which a plurality of pits functioning as the concave portion 16 are formed on a surface of a predetermined curvature functioning as the transfer film forming portion 18 as one form of the friction portion structure described above. It may be a surface having a peel structure.

  FIG. 3 shows a schematic view of the orange peel structure. As shown in FIG. 3, the orange peel structure is a technical term in the field derived from the surface shape of the orange peel, and the high hardness surface 13 a has a transfer film forming portion 18 a having a predetermined curvature (see FIG. In 3, it describes as curvature 0.) and pit 21 as crevice 16 formed in the shape of a hole. Such an orange peel structure can be obtained, for example, as innumerable rounded unevenness formed on the surface of a workpiece by polishing.

  Even with the friction portion 12 having such a high hardness surface 13a, the portion of the surface other than the pits 21, that is, the transfer film forming portion 18a functions as transfer film peeling promoting means, and the wear powder is enlarged. It can be done consistently.

  Further, as a further form of the friction portion structure, for example, the high hardness surface 13 has a structure in which a plurality of grooves functioning as the recess 16 are formed on the surface having a predetermined curvature functioning as the transfer film forming portion 18 It may be something.

  FIG. 4A shows a schematic view of a surface provided with such a plurality of groove structures. As shown in FIG. 4 (a), the high hardness surface 13b is a transfer film forming portion 18b (indicated as a curvature 0 as in FIG. 3) having a predetermined curvature, and a recess 16 formed in a groove shape. And the groove 22.

  Even with the friction portion 12 provided with such a high hardness surface 13b, a portion of the surface other than the groove 22, that is, the transfer film forming portion 18b functions as transfer film peeling promoting means, and the wear powder is enlarged. It can be done consistently.

  Further, as a further form of the friction portion structure, the high hardness surface 13 has, for example, a plurality of grooves functioning as the recess 16 formed in a lattice shape on the surface of a predetermined curvature, and adjacent as described in detail later The edges of the grooves parallel to each other may be partially overlapped to have a substantially sinusoidal waveform structure in a cross-sectional view orthogonal to the extending direction of the grooves.

  FIG. 4 (b) shows a schematic view of the high hardness surface 13c having such a corrugated structure. It should be noted that in order to make the asperity shape remarkable, the scale of the asperity direction is greatly enlarged, and in fact, the asperity shape is much smoother than illustrated.

  The waved structure shown in FIG. 4B can be regarded as a structure formed by overlapping the edge portions while making the groove spacing (the space of the concave portion 16) of the shape shown in FIG. The vicinity of the top portion thus formed is referred to as a transfer film forming portion 18c. In addition, in the transfer film forming portion 18c, a transfer film is formed in a snow-like state accumulated on the top of a mountain. In the waveform structure shown in FIG. 4B, although the transfer film forming portion 18c is not flat, since it has an extremely gentle uneven shape, transfer is actually performed by contact with the low hardness surface 14 A film 17 is formed. That is, the transfer film forming unit 18 can be understood as a region where the transfer film 17 is formed regardless of whether it is flat or not. In addition, the inner wall of the recess can be understood as a portion near the recess where the transfer film 17 is not formed.

  Even by the friction portion 12 provided with such a high hardness surface 13c, the edge portion and the transfer film forming portion 18c can function as transfer film peeling promoting means, thereby making it possible to steadily increase the wear powder size. .

  As described above, the friction part structure according to the present embodiment is a structure applicable to the friction parts in various mechanical parts, and has low friction resistance, suppression of the reduction of wear powder, and generation of wear powder. It solves three contradictory problems of quantity suppression, but if mechanical parts are particularly limited, it is particularly suitable for artificial joints from the viewpoint of the suppression of inflammation in the living body described above and the difficulty of maintenance. It can be said that it is a structure.

  That is, according to the artificial joint provided with the above-mentioned friction part structure, it is possible to suppress the generation of fine wear powder while realizing low friction resistance, and to suppress the generation amount of the wear powder itself. It is possible to provide an artificial joint having a friction part structure that can be

  In addition, the present specification also provides a method of forming a high hardness side friction surface that constitutes the above-described friction portion structure.

  That is, the present application is formed between a pair of members having different hardnesses, and among the pair of friction surfaces in the friction portion provided with a pair of friction surfaces that slide relatively while contacting each other in the presence of the lubricating fluid It also provides a method of forming a relatively hard surface.

  And one of the features in the method of forming a friction surface according to the present embodiment is the first abrasive liquid in which abrasive grains having a primary particle diameter of 1 μm to 5 μm are dispersed in the region forming the friction surface on the high hardness side. Lapping process to make the same area a surface with an arithmetic average roughness (Ra) of 10 nm to 20 nm, and a groove whose width gradually decreases from the surface side to the inside on the surface formed by the lapping process. Forming a recess having a shape of at least one of a circle and a hole, and diamond particles having a primary particle diameter of 2 nm to 5 nm in an area other than the recess at least in the surface formed in the recess forming step The second abrasive liquid, which is a dispersion in which a coagulated body having a secondary particle diameter of 2 nm to 20 nm is dispersed in a predetermined solvent, is polished, and the area other than this concave portion is arithmetic average roughness ( By setting Ra) to 1 nm to 3 nm, friction on the low hardness side Polishing a surface on the high hardness side having a surface structure as a transfer film separation promoting means for promoting separation of the transfer film transferred to the area other than the concave part by pressure contact sliding with a surface; Have.

  The first abrasive used in the lapping step is not particularly limited as long as it is an abrasive in which abrasives having a primary particle diameter of 1 μm to 5 μm are dispersed. For example, diamond or alumina is used as the abrasive. It can be used.

  A lapping process is performed by polishing the area | region which forms the high hardness side friction surface using such 1st abrasives, and making the area | region the surface of 10 nm-20 nm of arithmetic mean roughness (Ra).

  Here, if the arithmetic mean roughness of the surface is less than 10 nm, it is not preferable because it causes unnecessary concave portions that are difficult to remove. Moreover, if it exceeds 20 nm, the processing efficiency of the subsequent polishing step is significantly reduced, which is not preferable. By setting the arithmetic mean roughness to a surface of 10 nm to 20 nm, the subsequent polishing step can be favorably performed.

  The recess forming step is a step of forming the recess 16 on the surface having an arithmetic average roughness (Ra) of 10 nm to 20 nm. As described above, the recess 16 may be at least one of a groove and a hole whose width gradually decreases from the surface side to the inside.

  A well-known method can be suitably employ | adopted for formation of the recessed part 16, for example, can be based on erosion and etching.

  For example, if the recess 16 is the pit 21 described in FIG. 3, it may be formed by being subjected to a lapping process until the pit 21 is formed due to the occurrence of erosion or the dropping of a part of the metal crystal. Can. In addition, the recess forming step may be performed simultaneously with the lapping step.

  In particular, when forming the pits 21 by performing the recess formation process simultaneously with the lapping process, after starting the lapping process, polishing is performed while reducing the abrasive grains without supplying a new abrasive liquid, The formation of the surface having an arithmetic average roughness (Ra) of 10 nm to 20 nm and the formation of pits 21 by erosion can be performed efficiently and simultaneously.

  The polishing step is a step of polishing at least a region other than the recess in the surface formed in the recess forming step, that is, the surface of the transfer film forming portion 18 to set the arithmetic average roughness (Ra) to 1 nm to 3 nm.

  The polishing performed here is performed using the second abrasive liquid, which is the above-described dispersion, to transfer and transfer the surface of the transfer film forming portion 18 by press-contact sliding with the low hardness side friction surface. It is possible to form a high hardness side friction surface on which a surface structure is formed as a transfer film separation promoting means for promoting film separation.

  Further, in this polishing step, the peripheral edge of the recess 16 formed in the recess forming step is rounded to form a smooth curved surface, suppressing abrasive wear during pressure-contact sliding with the low hardness surface 14 and peeling off the lubricating fluid 15 It also has a role of improving the penetration into the start part 20.

  As described above, according to the method of forming a friction surface according to the present embodiment, it is possible to suppress the generation of fine wear powder while realizing low friction resistance, and further, the generation amount of the wear powder itself is also It is possible to form a frictional surface that can constitute a frictional portion structure that can be suppressed.

  In addition, as another characteristic configuration of the method of forming a friction surface according to the present embodiment, a first abrasive particle having a primary particle diameter of 1 μm to 5 μm is dispersed in a region forming the friction surface on the high hardness side. Polishing with abrasive liquid to make the same area have a surface with an arithmetic average roughness (Ra) of 10 nm to 20 nm, and the first abrasive liquid or abrasive particles with a primary particle diameter of 2 nm to 5 nm in a predetermined solvent And a second abrasive liquid, which is a dispersion dispersed in the above, is linearly converged on the surface formed in the lapping step while scanning it longitudinally and transversely to form a grid-like groove, When forming a parallel groove adjacent to a groove, the edge portion of the groove to be newly formed is scanned while being partially overlapped with the edge portion of the groove formed, and a cross sectional view orthogonal to the scanning direction of both grooves And the arithmetic mean roughness (Ra) of the scanned area is the first or By setting the thickness to 1 nm to 3 nm by the collision of the abrasive liquid of 2, the transfer film peeling that promotes the peeling of the transfer film transferred to the area near the top of the corrugated structure by pressure contact sliding with the low hardness side friction surface And a recessed portion forming step to be a friction surface on the high hardness side on which a surface structure is formed as a promoting means.

  FIG. 5: is explanatory drawing which shows the apparatus structure which can be used at the recessed part formation process which concerns on the above-mentioned other characteristic structure. There are no particular limitations on the equipment used to perform the recess-type process, but this can also be realized by using, for example, a micro-slurry erosion device 40 shown in FIG.

  The micro-slurry erosion device 40 is a device that sprays the abrasive liquid onto the object in a state where the abrasive liquid is converged into a very thin linear shape by air pressure, and supplies the abrasive liquid (first or second abrasive liquid) from the abrasive liquid introduction unit 41 However, by supplying compressed air from the air supply unit 42, the abrasive fluid flow 44 can be sprayed from the tip nozzle 43 onto the high hardness member 10 at high speed.

  In addition, the micro slurry erosion device 40 and the high hardness member 10 are configured to be movable relative to each other. That is, the surface of the high hardness member 10 is abraded by moving the micro slurry erosion device 40 relative to the high hardness member 10 or, conversely, moving the high hardness member 10 relative to the micro slurry erosion device 40. It is possible to scan with the liquid flow 44.

  Therefore, by scanning the surface of the high hardness member 10 longitudinally and horizontally (in a lattice) at the predetermined scanning speed with the abrasive fluid flow 44, the high hardness of the grooved groove as shown in FIG. 4 (a) or 4 (b) The surface 13 can be formed.

  Further, in particular, in the high hardness surface 13c shown in FIG. 4B, the edges of adjacent grooves parallel to each other are partially overlapped.

  FIG. 6 is an explanatory view showing a process of forming the high hardness surface 13c shown in FIG. 4B by the micro slurry erosion device 40. As shown in FIG. As shown in FIG. 6A, when forming a corrugated structure such as the high hardness surface 13c, the surface of the high hardness member 10 is scanned linearly with the abrasive liquid flow 44, as shown by a solid line. First, one groove 22 is formed.

  At this time, when the abrasive fluid flow 44 jetted to the high hardness member 10 is reflected on the surface of the high hardness member 10 by its momentum, the foundation of the high hardness member 10 is formed from the side wall surface of the groove portion expanding upward. A smooth curved edge 46 is formed which leads to a flat surface. The edge portion 46 is also a portion functioning as a transfer film peeling means.

  Next, in forming the parallel groove 22 adjacent to the formed groove 22, the edge 46 of the groove 22 to be newly formed is partially overlapped with the edge 46 of the formed groove as shown by a broken line. While scanning.

  By repeating this a plurality of times, as shown in FIG. 6B, a substantially sinusoidal waveform structure is formed in a cross sectional view orthogonal to the extending direction of the groove.

  The groove width p and the depth q of the corrugated structure thus formed are not particularly limited, but preferably the groove width p is 0.5 mm to 5 mm, and the depth q is 35 nm to 200 nm, as described above. By doing this, it is possible to suppress the generation of fine wear powder while realizing low friction resistance, and moreover, it is possible to configure a friction part structure capable of suppressing the generation amount of wear powder itself. Can be formed. The region where such a corrugated structure is formed is in a state in which substantially the entire surface has been polished by the abrasive fluid flow 44, that is, a surface state in which a polishing process is performed. This is considered to be due to the formation of innumerable collision marks (nanometer erosion) due to the collision of the abrasive grains with the high hardness surface 13. Therefore, according to the recess forming process according to the other characteristic configuration, it is possible to omit the polishing process separately. However, this does not prevent the implementation of the polishing process as needed.

  By the way, the friction part structure according to the present embodiment can also be considered to improve the wear characteristics in the friction part where direct contact between the friction surfaces is required if it is caught by another different cut.

  For example, in a shaft sealing device or the like provided around a shaft rotatably or reciprocably supported and provided with a seal member for securing liquid tightness around the shaft, the shaft and the like for improving liquid tightness. Although tightness with the seal member is required, if the seal member is in close contact with the shaft, liquid tightness is improved but frictional resistance is increased. On the other hand, if the contact is loosened Although the frictional resistance is reduced, there is a problem that the liquid tightness is reduced.

  On the other hand, the friction part structure according to the present embodiment can realize low friction resistance and low abrasion while contacting the friction surfaces, and is an extremely useful technique in such a shaft sealing device or the like. It can be said that there is.

  Hereinafter, the structure of the friction portion, the method of forming the friction surface, and the like according to the present embodiment will be described in more detail with experimental results and the like. In the following, an example in which the structure shown in FIG. 3 and FIG. 4 (a) is examined first will be shown as Example 1, and an example in which the structure shown in FIG.

Example 1
[1. Formation of high hardness side friction surface]
First, the formation of the high hardness side friction surface is mentioned. In this embodiment, as a pair of members having different hardnesses, one member having a relatively high hardness is a cobalt chromium molybdenum alloy (Co-28Cr-Mo), and the other member having a relatively low hardness is an ultrahigh molecular weight polyethylene ( Average molecular weight was 6 million).

  As shown in FIG. 5, the lapping process was performed by performing lapping processing on a region (hereinafter, simply referred to as a formation region) which forms the friction surface on the high hardness side in the surface of the high hardness member.

  Specifically, an abrasive liquid obtained by dispersing abrasive particles having a particle diameter of 1 μm to 5 μm made of diamond or alumina in a predetermined dispersion medium is used as a first abrasive liquid, and the above-described high hardness member is used as a lapping apparatus. Then, lapping was performed so that the arithmetic mean roughness (Ra) of the surface was 10 nm to 20 nm.

  After the first abrasive liquid is supplied at the initial stage of lapping, the abrasive grains are abraded while being abraded without causing additional replenishment, and pits are formed by causing erosion on the surface of the high hardness member. The That is, the recess formation step was performed together with the lapping step to form an orange peel structure.

  Next, the polishing process was performed by polishing with a second abrasive liquid until the arithmetic average roughness (Ra) became 1 nm to 3 nm with respect to at least a region other than the recess in the surface formed in the recess forming step.

  As the second abrasive liquid, an aqueous dispersion of nanodiamond particles having a primary particle diameter of 2 nm to 5 nm (trade name "Ustalla (registered trademark) Type A" manufactured by Nippon Kayaku Co., Ltd.) was used. The second abrasive liquid is a dispersion in which diamond particles having a primary particle diameter of 2 nm to 5 nm are dispersed in a predetermined solvent, and a coagulated body formed by aggregating diamond particles is disintegrated. It is dispersed as a crushed material having a particle size distribution of 2 nm to 20 nm obtained. FIG. 6 shows the particle size distribution measurement data of this second abrasive liquid. As can also be seen from FIG. 6, it can be seen that the second abrasive fluid used is a dispersion finely divided to 2 nm to 20 nm.

  Thus, by passing through the polishing step, a surface structure as a transfer film peeling promoting means for promoting the peeling of the transfer film transferred to the area other than the concave portion by pressure contact sliding with the low hardness side friction surface. Thus, a high hardness member A provided with the high hardness side friction surface (L-2) formed was obtained. The high hardness member A provided with the friction surface (L-2) is a high hardness member A capable of forming the friction portion structure according to the present embodiment.

  Moreover, creation of the other high hardness member B which can build the friction part structure which concerns on this embodiment was also performed. The high hardness member B is different in structure from the high hardness member A in that the recess structure formed on the friction surface is groove-shaped.

  Specifically, first, the high hardness member is subjected to the lapping apparatus with the above-mentioned first abrasive liquid, and the first abrasive liquid is additionally supplied or not during the lapping process without causing erosion. In addition, lapping was performed such that the arithmetic mean roughness (Ra) of the surface was 10 nm to 20 nm.

  Next, in the formation region subjected to the lapping process, grid-like grooves as a plurality of recesses were formed by etching or erosion, and a recess-type process was performed. The lattice spacing was 500 μm, the groove width was 250 μm, and the groove depth was 35 nm to 65 nm.

  Next, by performing the polishing process in the same manner as the above-described high hardness member A with respect to the formation area having undergone the recess type process, the transfer transferred to the area other than the recess by press-contacting sliding with the low hardness side friction surface. A high-hardness member B was obtained which has a high-hardness-side friction surface (X-1) on which a surface structure is formed as a transfer film separation promoting means for promoting separation of the deposited film.

  Further, in addition to the high hardness member A and the high hardness member B, a friction surface (G-to which only the lapping process is applied to the formation region of the high hardness member is provided as a comparison target for verification and testing described below. 1) A method of forming the same as the high hardness member Z1 and the high hardness member A, but the depth of the pit as a recess is deep and the friction surface (L can not spill out the lubricating fluid by having an excessive capacity) The same method as in the case of the high hardness member Z2 and the high hardness member A, but the depth of the pit as a recess is small, and the friction surface can not store the lubricating liquid in an amount capable of promoting the peeling of the transfer film. It formed also about high hardness member Z3 provided with (L-3).

[2. Verification of high hardness side friction surface]
Next, the above-mentioned [1. Formation of High-Hardness Side Friction Surface] The properties of each of the friction surfaces G-1, L-1, L-2, L-3, and X-1 formed in the above were verified. The results are shown in Table 1.

  As can be seen from Table 1, it was shown that the surface roughness of G-1 was rough as compared to the surface roughness of L-1 to L-3 and X-1. In addition, it was shown from the surface analysis result of G-1 that a relatively sharp asperity remains.

  On the other hand, it was shown that the surface roughness of each of L-1 to L-3 and X-1 was as smooth as several nm. However, according to the surface analysis results of these friction surfaces, the concave portion formed in L-1 has a large capacity so as not to promote spillage of the contained lubricating fluid, and the concave portion formed in L-3 has the transfer film It was shown that only a sufficient amount of lubricating fluid could be stored to delaminate. In addition, the concave portions formed in L-2 and X-1 can accommodate lubricating fluid sufficient for peeling of the transfer film, and the contained lubricating fluid can also spill out with sliding of the friction surface. It was shown to be.

[3. Friction resistance confirmation test]
Next, with respect to each of the friction surfaces G-1, L-1, L-2, L-3, and X-1, a test was conducted on the frictional resistance with a relatively low hardness member (ultrahigh molecular weight polyethylene). As a result, it was shown that G-1> L-1 ≒ L-2 ≒ X-1> L-3.

[4. Confirmation test of the amount of wear]
Next, with respect to each of the friction surfaces G-1, L-1, L-2 and L-3, the amount of wear at the time of sliding when constructing a member (ultrahigh molecular weight polyethylene) having a relatively low hardness and a friction portion Were confirmed by the Pin-on-disc method. In this test, 25% bovine serum aqueous solution was used as the lubricating fluid. The results are shown in FIG.

  As can be seen from FIG. 7, in the L-1 and L-2, a decrease in wear was observed as compared with the friction surface G-1 which was subjected only to the lapping step. In particular, L-2 resulted in the lowest amount of wear. L-3 also resulted in increased wear. This is thought to be because the lubricating liquid is induced and stored in the concave portions formed in L-1 and L-2, and the high hardness member Z2 or the high hardness member A and the low hardness member are in a non-lubricant state. Be That is, it was considered that due to such a state, the transfer film was formed on the surface of the high hardness member, that is, the surface of the transfer film forming portion, and the wear was reduced along with the self-lubricating action. On the other hand, in the case of L-3, the volume of the recess was insufficient, and the induction and storage of the lubricating fluid were insufficient, and it was considered that the adhesive wear was apparent.

[5. Particle size distribution measurement of wear powder]
For each friction surface G-1, L-1, L-2, L-3, the particle size of wear powder generated during sliding when constructing a member (ultrahigh molecular weight polyethylene) with relatively low hardness and friction part We confirmed the distribution. The results are shown in FIG.

  As shown in FIG. 8, it was revealed that the size of the wear powder was larger in any of L-1 to L-3 as compared with the friction surface G-1 which was subjected only to the lapping step.

  When the transfer film is formed on the high hardness surface of the friction portion not provided with the friction portion structure according to the present embodiment, although the amount of wear decreases, there is a problem that the size of the wear powder also decreases.

  However, in the case of L-1 to L-3, exfoliation of the transfer film is promoted by the lubricating fluid induced and stored in the recess overflowing. Then, the peeled transfer film is aggregated and enlarged between the friction surfaces whose lubrication state is not sufficient, and as a result, the size of the wear powder is increased.

  And [3. Frictional resistance confirmation test] to [5. When comprehensively considering the results of the particle size distribution measurement of the wear powder], although L-2 capable of constructing the friction part structure according to the present embodiment realizes low friction resistance, generation of fine wear powder It can be seen that the surface is a high hardness surface which can suppress the generation of wear powder and also can suppress the generation amount of wear powder itself.

Example 2
Next, an example in which the structure shown in FIG.

[1. Formation of high hardness side friction surface]
First, the formation of the high hardness side friction surface is mentioned. Also in Example 2, as a pair of members having different hardnesses, one member of relatively high hardness is a cobalt chromium molybdenum alloy (Co-28Cr-Mo), and the other member of relatively low hardness is an ultra high molecular weight It was polyethylene (average molecular weight 6 million).

  Next, a polishing solution prepared by dispersing abrasive particles having a particle diameter of 1 μm to 5 μm composed of diamond or alumina in a predetermined dispersion medium is used as a first polishing solution, and the above-mentioned high hardness member is applied to a lapping machine. Lapping was performed on the formation region so that the arithmetic mean roughness (Ra) of the surface was 10 nm to 20 nm.

  Next, using the above-described micro-slurry erosion device 40, the first or second abrasive liquid described above is ejected while linearly converging on the surface formed in the lapping process, and the abrasive liquid flow 44 scans lengthwise and crosswise did.

  When forming a parallel groove adjacent to the formed groove, scanning is performed while partially overlapping the edge of the formed groove with the edge of the newly formed groove, and the scanning direction of both grooves It was made to have a waveform structure of a substantially sine wave in the cross-sectional view orthogonal to form a grid-like groove structure shown in FIG. 4 (b).

  Thus, by passing through the concave portion forming step, as a transfer film peeling promoting means for promoting the peeling of the transfer film transferred to the transfer film forming portion 18c by the pressure contact sliding with the low hardness side friction surface. The high hardness member C provided with the high hardness side friction surface (M) on which the surface structure was formed was obtained. The high hardness member C provided with the friction surface (M) is a high hardness member capable of forming the friction portion structure according to the present embodiment.

[2. Verification of high hardness side friction surface]
As a result of analyzing the friction surface (M) of the high hardness member C, the groove width p of the groove 22 was 1 mm, and the depth q was 180 nm. Further, it was confirmed by the scanning with the abrasive liquid flow 44 that the arithmetic mean roughness (Ra) of the formed region was 2 nm, and that substantially the same effect as the polishing step was obtained.

[3. Friction resistance confirmation test]
Next, with respect to the friction surface (M), a test was conducted on the frictional resistance with a relatively low hardness member (ultrahigh molecular weight polyethylene). As a result, it was shown that the frictional resistance was substantially equivalent to that of L-2 and X-1 described above.

[4. Confirmation test of the amount of wear]
Next, with respect to the friction surface (M), the amount of wear at the time of sliding when constructing a member (ultrahigh molecular weight polyethylene) having a relatively low hardness and the friction portion was confirmed by the Pin-on-disc method . In addition, in this test, the friction surface (G2) of the high hardness member subjected only to the lapping process as a comparative object was also examined. The data of the surface state of the friction surface (M) and the friction surface (G2) are shown in Table 2.

  In addition, 25% bovine serum aqueous solution was used as the lubricating fluid in this test. The result is shown in FIG.

  As can be seen from FIG. 11 (a), in the friction surface (M), a decrease in wear was observed as compared with the friction surface (G2) subjected only to the lapping step. In particular, the amount of wear on the friction surface (M) was about 0.6 mg on average, which was lower than the above-mentioned L-2.

[5. Particle size distribution measurement of wear powder]
With respect to each of the friction surfaces G2 and M, the particle size distribution of wear powder generated at the time of sliding when a member (ultrahigh molecular weight polyethylene) having a relatively low hardness and a friction portion were constructed was confirmed. The result is shown in FIG.

  As shown in FIG. 11 (b), the size of the wear powder on the friction surface (M) is larger than that of the friction surface G2 subjected only to the lapping process, and the size of 0.2 μm to 1.0 μm is classified. It was found that the amount of wear was significantly reduced. In particular, the distribution tendency of the wear powder on the friction surface (M) shows better results than the above-mentioned L-2.

[6. Measurement of expression level of inflammation related substance]
Next, the amount of cytokines released from macrophages, in particular IL-6 (interleukin-6) and TNF-α, is measured using the attrition powder obtained on each friction surface G2, M, and the inflammation suppression effect We examined whether or not we were obtained.

  Specifically, human monocyte-derived macrophages (HMDM) were cultured together with attrition powder obtained on each friction surface G2, M, and the amount of secreted IL-6 and TNF-α was measured. . The result is shown in FIG.

  As can be seen from FIG. 11 (c), in both IL-6 and TNF-α, the wear powder generated on the friction surface M is smaller than the wear powder on the friction surface G2 subjected only to the lapping step. It was shown that the amount of cytokine production was low.

  That is, it was shown that the friction portion structure according to the present embodiment and the friction surface obtained by the method of forming the friction surface are less likely to cause inflammation in a living body.

  As described above, according to the friction portion structure according to the present embodiment, a pair of friction surfaces which are formed between a pair of members with different hardness and relatively slide in contact with each other in the presence of the lubricating liquid In the structure of the provided friction portion, the friction surface having relatively high hardness among the pair of friction surfaces is a transfer film forming portion where the transfer film is formed by contact with the friction surface having relatively low hardness. And at least one of a groove shape and a hole shape in which the width gradually narrows from the surface side to the inside of the high hardness friction surface, and is present on the surface of the transfer film forming portion when the pair of friction surfaces are in pressure contact. And a concave portion having a volume capable of causing the lubricating fluid to flow in and storing the same surface substantially in a non-lubricating liquid state, and the surface of the transfer film forming portion is a pressure contact slide of the pair of friction surfaces. It forms on the surface of the said transfer film formation part by the lubricating fluid which overflowed from the said recessed part with movement. Since the transfer film separation promoting means for promoting the separation of the transfer film is provided, generation of fine wear powder can be suppressed while realizing low friction resistance, and moreover, wear powder It is possible to provide a friction portion structure that can also suppress the generation amount of itself.

  Finally, the description of each of the above-described embodiments is an example of the present invention, and the present invention is not limited to the above-described embodiments. For this reason, even if it is a range which does not deviate from the technical idea concerning the present invention even if it is other than each embodiment mentioned above, it is needless to say that various change is possible according to a design etc.

DESCRIPTION OF SYMBOLS 10 High hardness member 11 Low hardness member 12 Friction part 13 High hardness surface 14 Low hardness surface 15 Lubricant 16 Concave part 17 Transfer film 18 Transfer film formation part 19 Fine friction powder 20 Peeling start part 21 Pit 22 Groove 30 Large wear powder

Claims (9)

In the structure of a friction part provided with a pair of friction surfaces which are formed between a pair of members of different hardness and which slide relative to each other in the presence of a lubricating fluid,
Of the pair of friction surfaces, the relatively hard one is
A transfer film forming portion in which a transfer film is formed by contact with a relatively low hardness friction surface;
Anda recess having a substantially capacity to the unlubricated liquid state of the same surface accommodated by introducing the lubricant present on the surface of the transfer film deposition forming portion during pressing prior Symbol pair of friction surfaces ,
The surface of the transfer film forming part promotes the peeling of the transfer film formed on the surface of the transfer film forming part by the lubricating liquid overflowing from the recess along with the pressure contact sliding of the pair of friction surfaces. Transfer film peeling promoting means ,
The high-hardness friction surface has a structure in which a plurality of grooves functioning as the concave portion whose width gradually narrows from the surface side to the inside is formed on the surface having a predetermined curvature functioning as the transfer film forming portion And
The plurality of grooves are formed in a lattice shape on the surface, and the edges of adjacent grooves parallel to each other are partially overlapped to form a substantially sinusoidal wave structure in a cross-sectional view orthogonal to the extending direction of the grooves The friction part structure characterized by.   The friction part structure according to claim 1, wherein the transfer film separation promoting means is a surface structure of the transfer film forming part having an arithmetic mean roughness (Ra) of 1 nm to 3 nm.   3. The friction part structure according to claim 2, wherein the surface structure is a surface of a diamond particle having a primary particle diameter of 2 nm to 5 nm and dispersed in a predetermined solvent.   The dispersion has dispersed therein a crushed material having a particle size distribution of 2 nm to 20 nm obtained by crushing a coagulated body formed by aggregating the diamond particles having the primary particle diameter of 2 nm to 5 nm. The friction part structure according to claim 3, characterized in that: The artificial joint provided with the friction part structure according to any one of claims 1 to 4 . A dispersion formed by dispersing diamond particles having a primary particle diameter of 2 nm to 5 nm in a predetermined solvent, for forming transfer film separation promoting means in the friction portion structure according to any one of claims 1 to 4. Use as a polishing agent. The dispersion is a dispersion of crushed material having a particle size distribution of 2 nm to 20 nm obtained by crushing a coagulated body formed by aggregating diamond particles having a primary particle diameter of 2 nm to 5 nm. The use according to claim 6 , characterized in that: Relatively high hardness among the pair of friction surfaces in the friction portion provided with a pair of friction surfaces which are formed between a pair of members of different hardnesses and relatively slide in contact with each other in the presence of lubricating fluid A method of forming the side friction surface,
The area forming the high hardness side friction surface is polished with a first abrasive liquid in which abrasive grains having a primary particle diameter of 1 μm to 5 μm are dispersed, and the area is arithmetic average roughness (Ra) of 10 nm to Lapping process with 20 nm surface,
The first abrasive liquid or a second abrasive liquid, which is a dispersion in which abrasive grains having a primary particle diameter of 2 nm to 5 nm are dispersed in a predetermined solvent, is linear to the surface formed in the lapping step. At the same time when forming parallel grooves adjacent to the formed groove, the edge of the groove to be newly formed is formed by spraying while performing convergence and scanning vertically and horizontally to form a lattice-like groove. The scanning is carried out while partially overlapping the edge portion to form a substantially sinusoidal waveform structure in a cross-sectional view orthogonal to the scanning direction of both grooves, and the arithmetic average roughness (Ra) of the scanned area is the first or second Transfer film peeling promoting means for promoting peeling of the transferred film transferred to the area near the top of the above-mentioned waveform structure by pressure sliding with the low hardness side friction surface by setting the thickness to 1 nm to 3 nm by the collision of the abrasive liquid Forming a concave surface on the high hardness side on which the surface structure as a surface is formed
A method of forming a friction surface comprising: In the dispersion, a crushed material having a particle size distribution of 2 nm to 20 nm obtained by crushing a coagulated body formed by aggregating the diamond particles having a primary particle diameter of 2 nm to 5 nm is dispersed as abrasive grains. method of forming a friction surface according to 請 Motomeko 8 characterized in that which is.