JP5917646B2 - Manufacturing method of sliding member - Google Patents

Description

The present invention relates to a method for producing a sliding member.

  In rolling bearings, the raceway surface and rolling elements (balls) that roll on the raceway surface, for example, are seized or smeared on the contact surface when used in an environment where a heavy load is applied or an environment with rapid acceleration. Damage such as a ring sometimes occurred. Therefore, a lubricant is interposed between the rolling elements and the raceway surface in a film form, that is, an oil film is formed so as to reduce the friction between the two sliding surfaces.

  And conventionally, in order to improve the oil film forming ability, a structure in which concave grooves are periodically formed on the raceway surface has been proposed (Patent Document 1). That is, as shown in FIG. 14, a plurality of fine groove grooves are formed at a predetermined pitch along a direction perpendicular to the traveling direction of the ball 50 on the raceway surface 51 on which the ball 50 as a rolling element rolls. Thus, the periodic structure 52 is provided.

  In this case, the ball 50 contacts within the range indicated by the contact ellipse 53 at the center (bottom) in the width direction of the raceway surface 51. When the ball 50 rolls and slides along the raceway surface 51, the area indicated by the reference numeral 54 in which the contact ellipse 53 is orthogonal to the direction in which the groove groove of the periodic structure 52 extends is in contact with the raceway 51. It becomes a contact passage area which passes through.

  On both sides of the contact passing region 54, slip occurs between the ball 50 that slides and slides and the raceway surface 51, and this slip causes dynamic pressure to the lubricating oil in the groove extending in the direction perpendicular to the direction of rolling and sliding. Will occur. Then, the lubricating oil is influenced by the dynamic pressure due to the sliding, and is drawn between the convex portion between the concave grooves on the raceway surface and the ball 50. As a result, on both sides of the contact passage region 54, the lubricating oil can be interposed between the raceway surface (specifically, the convex ridge portion between the concave grooves) and the sphere, and an oil film can be formed.

  On the other hand, in the contact passing area 54, the sphere rolls purely, and slip hardly occurs between the sphere and the raceway surface, so that the dynamic oil due to the slip is hardly generated in the lubricating oil in the concave groove of the contact passing area 54. . Therefore, in the contact passage region 54, even if the concave groove is formed, it is not possible to obtain the oil film forming action due to the slip as described above. Further, in the contact passing region, the lubricating oil drawn into the contact passing region 54 flows out along the concave groove as the sphere rolls and slides. For these reasons, in the contact passage region 54, it is considered that the frictional force is increased by forming the concave groove, so that there is a problem that the friction reducing action as the entire raceway surface cannot be effectively obtained.

JP-A-2005-32148

  Therefore, conventionally, as shown in FIG. 15, a structure in which the periodic structure 52 is not provided in the contact passage region 54 has been proposed. That is, since the periodic structure 52 is formed in the raceway surface other than the contact passage region 54, an oil film that promotes the generation of dynamic pressure can be formed. Moreover, since the periodic structure 52 is not formed in the contact passage region 54, the outflow of the lubricating oil to the outside can be prevented, and the formation of the oil film can be maintained. For this reason, by adopting the configuration as shown in FIG. 15, a good friction reducing action is exhibited over the entire raceway surface.

  As described above, an extremely excellent friction reducing action can be exerted on a constant contact passage region (Hertz contact region). However, in a general sliding member, the Hertz contact area varies depending on the load applied, the material of the sliding member, the sliding condition such as the shape of the sliding member, and the variation in the mounting position of the sliding member. It will be. For this reason, there is a possibility that the friction reducing action cannot be exhibited depending on the sliding condition.

In view of the above problems, the present invention can stably exhibit a good friction reducing action without being affected by fluctuations in the Hertz contact area and without performing high-precision alignment between sliding surfaces. to provide a method of manufacturing a can Ru sliding member.

  The manufacturing method of the sliding member of the present invention includes a first member having a convex curved sliding surface and a second member having a sliding surface that slides relative to the sliding surface of the first member. And forming a periodic structure of grating-like irregularities in which the convex vertex is a non-flat surface and the height continuously changes on the sliding surface of the first member. A periodic structure forming step, a mirror surface finishing step of mirror-finishing the sliding surface of the second member with a higher surface hardness than the sliding surface of the first member, a sliding surface of the first member and the sliding surface of the second member And a wear step of sliding the moving surface relative to each other under lubrication to wear the periodic structure as a sacrificial layer.

  According to the manufacturing method of the sliding member of the present invention, since the periodic structure of the grating-like irregularities whose height continuously changes is provided in the first member whose hardness is lower than that of the second member, the tip of the periodic structure at the time of sliding Wears selectively and familiarity progresses. At this time, fine wear powder is generated from the first member, but the periodic structure prevents the wear powder from being caught. Further, since the lubricant held in the periodic structure acts on the new surface promptly, the periodic structure of the sliding trace can be worn out with little disturbance.

  The periodic structure of the grating-like irregularities on the sliding surface of the first member remains on the periphery of the sliding trace, and the remaining periodic structure dimension perpendicular to the sliding direction is twice the sliding trace dimension orthogonal to the sliding direction. The above is preferable.

  It is preferable that the periodic structure of the grating-like irregularities is orthogonal to the sliding direction. The absolute value of the radius of curvature of the sliding surface of the first member may be equal to or less than the absolute value of the radius of curvature of the sliding surface of the second member.

  The periodic structure formed on the substrate surface of the first member may be formed in a self-organized manner by irradiating linearly polarized laser with an irradiation intensity near the processing threshold and scanning while overlapping the irradiated portions. preferable.

Moreover, the irregularities height difference of the periodic structure and 50nm or 500nm or less, and the period of the first member having a periodic structure of the grating-like unevenness protrusion vertex continuously height in a non-planar surface is changed preferred periodic pitch structures to the 10μm or less.

  In the present invention, the periodic structure is formed in the peripheral part of the Hertz contact area without depending on the load applied, the sliding member material, the sliding condition such as the shape of the sliding member, or the variation in the mounting position of the sliding member. Can be formed. For this reason, it is possible to form a low-friction sliding surface in which a periodic structure is arranged on the periphery of the Hertz contact area without performing highly accurate positioning. That is, the present invention is not limited to sliding conditions and can exhibit a good friction reducing action without performing high-accuracy positioning, and includes partial solid contact and elastohydrodynamic lubrication. It is possible to provide a sliding member that has low friction in a portion where a mixture exists.

  When the residual size of the periodic structure perpendicular to the sliding direction is more than twice the size of the sliding trace perpendicular to the sliding direction, the oil film increase effect due to the periodic structure remaining at the periphery of the Hertz contact area can be efficiently obtained. Can do.

  When the periodic structure of the grating-like irregularities provided on the first member is perpendicular to the sliding direction, the recess holding the lubricant intermittently passes through the sliding surface of the second member, so that the oil film is prevented from being cut. The periodical structure of the sliding trace can be worn out with less disturbance.

  If the absolute value of the radius of curvature of the first member is less than or equal to the absolute value of the radius of curvature of the second member, the oil film increasing effect due to the periodic structure remaining at the peripheral edge of the Hertz contact area can be obtained efficiently. The sliding surface shape of the second member can be a flat surface or a concave curved surface.

  By irradiating a linearly polarized laser beam with an irradiation intensity in the vicinity of the processing threshold, scanning the overlapping parts, and forming them in a self-organized manner, it is difficult to machine with a submicron periodic pitch and uneven depth. A periodic structure with can be easily obtained.

The first member having the periodic structure of the grating-like unevenness has an uneven height difference of this periodic structure of 50 nm to 500 nm and the periodic pitch of this periodic structure is 10 μm or less. Since the lubricant retained in the prevention and periodic structure acts quickly on the new surface, the periodic structure of the sliding trace can be worn out with less disturbance.

It is a simplified block diagram which shows the process of the manufacturing method of the sliding member which shows embodiment of this invention. It is a perspective view of the manufacturing method of the sliding member which shows embodiment of this invention. The sliding surface of a 1st member is shown, (a) is an enlarged plan view of a periodic structure, (b) is a cross-sectional profile figure of a periodic structure. It is a simplification figure of the laser surface processing apparatus used for the manufacturing method of a sliding member. It is a graph for demonstrating the definition of arithmetic mean roughness. The relationship between the periodic structure and the Hertz contact area is shown, (a) is a simplified diagram when the periodic structure is present on the entire surface, and (b) and (c) are the cases when the periodic structure remains on the periphery of the sliding trace. It is a simplified diagram. The relationship between a 1st member and a 2nd member is shown, (a) is a simplified view when the curvature radius of the sliding surface of a 2nd member is infinite, (b) is a sliding surface of a 1st member. FIG. 6C is a simplified diagram when the absolute value of the radius of curvature of the second member is smaller than the absolute value of the radius of curvature of the sliding surface of the second member, and FIG. It is a simplification figure when it is smaller than the absolute value of the curvature radius of the sliding surface of a member, (d) is the absolute value of the curvature radius of the sliding surface of a 1st member, and the curvature radius of the sliding surface of a 2nd member. It is a simplified diagram when the absolute value is the same. It is a graph which shows the relationship between the frequency | count of a reciprocation and the friction coefficient at the time of reciprocating the periodic structure of a 1st member with respect to the mirror-finished sliding surface of a 2nd member. The sliding trace of the first member (ball) when the first member is reciprocated 10,000 times with respect to the mirror-finished sliding surface of the second member, (a) is a photograph of a raw ball, (B) is a photograph when a ball having a periodic structure is slid in a direction orthogonal to the periodic structure, and (c) is a ball having a periodic structure slid in a direction parallel to the periodic structure. FIG. It is a 3D image diagram of the sliding surface of the first member (ball) when the ball is reciprocated 10,000 times in the direction parallel to the periodic structure with respect to the mirror-finished sliding surface of the second member. It is a profile figure of the sliding surface of the 1st member (ball) when a ball is reciprocated 10,000 times in the direction parallel to a periodic structure with respect to the sliding surface which finished the mirror finish of the 2nd member. The sliding surface of the second member when the ball is reciprocated 10,000 times with respect to the mirror-finished sliding surface of the second member is shown. (A) shows the sliding surface when the raw ball is slid. It is a profile figure, (b) is a profile figure of a sliding surface when a ball in which a periodic structure is formed is slid in a direction orthogonal to the periodic structure, and (c) is a ball in which a periodic structure is formed. It is a profile figure when it is made to slide in a direction parallel to a periodic structure. The relationship between the satellite-like oil film and the sliding trace is shown, (a) and (b) are distribution diagrams of the oil film thickness, and (c) is a diagram in which a ball with a periodic structure formed is slid in a direction parallel to the periodic structure. FIG. A conventional rolling bearing is shown, (a) is a simplified cross-sectional view showing the relationship between the ball and the raceway surface, and (b) is a simplified development view showing the relationship between the periodic structure formed on the raceway surface and the ball. It is. It is a simple development view showing the relation between the track surface and the ball which are not provided with the periodic structure in the contact passage region.

  Hereinafter, embodiments of the present invention will be described with reference to FIGS.

  FIG. 1 is a block diagram showing a manufacturing method of a sliding member according to the present invention, and this manufacturing method includes a periodic structure forming step P1, a mirror finishing step P2, and a wear step P3. As shown in FIG. 3, the periodic structure forming step P <b> 1 forms the grating-like irregular structure 3 on the sliding surface 1 a of the first member 1, and the mirror finishing step P <b> 2 is the sliding of the second member 2. This is a step of mirror-finishing the surface 2a. In the wear step P3, the sliding surface 1a of the first member 1 and the sliding surface 2a of the second member 2 are relatively slid to make the periodic structure 3 a sacrificial layer. It is something to wear out.

  FIG. 2 shows a schematic diagram of a reciprocating ball-on-plate testing machine. In this example, the first member 1 is a sphere, and the second member 2 is a flat plate. The first member 1 is made of metal such as SUJ2 (high carbon chromium bearing steel), and the second member 2 is made of metal such as SUS440C (martensitic stainless steel).

As shown in FIG. 4, the periodic structure forming step P <b> 1 is formed using a laser surface processing apparatus including a laser generator 11 and an optical system 10. In this laser surface processing apparatus, the laser generator 11 is folded back toward the processing material W by the mirror 12 and guided to the mechanical shutter 13. At the time of laser irradiation, the mechanical shutter 13 is opened, the laser irradiation intensity can be adjusted by the half-wave plate 14 and the polarization beam splitter 16, the polarization direction is adjusted by the half-wave plate 15, and the condenser lens 17 The surface of the work material W on the XYθ stage 19 is focused and irradiated.

  In the periodic structure forming step P1, linearly polarized laser is irradiated with an irradiation intensity in the vicinity of the processing threshold, and the irradiated portions are scanned while being overlapped to form in a self-organized manner. That is, when a workpiece (working material) W is irradiated with a linearly polarized laser beam at a fluence near the ablation threshold, interference between the incident light and the scattered light or plasma wave along the surface of the processing material W is approximately the same as the laser wavelength. At periodic intervals, a slight roughness occurs in the energy distribution. In a general processing method, the entire laser irradiation surface is processed, but a high energy portion can be selectively processed by laser irradiation at an energy density near the processing threshold. As a result, a grating-like periodic structure is formed while performing laser irradiation with one optical axis. At this time, the longer the pulse width of the laser used for processing, the more disturbed the periodic structure is due to the influence of heat and the scattering of the laser due to the interaction with the processed evaporation.

  In this embodiment, an amorphous carbon film (DLC film) is formed on the surface of the second member 2 in the film forming process, and this surface constitutes the sliding surface 2a. For the film forming step, for example, a plasma ion implantation method can be employed. The plasma ion implantation method is a method of forming a film by ionization vapor deposition which is a plasma process in a high vacuum. In other words, toluene gas or other hydrocarbon gas is introduced into the vacuum chamber, and radicals in which hydrocarbon ions are excited in DC arc discharge plasma are generated. For this reason, hydrocarbon ions collide with a substrate (a member to be coated) biased to a negative DC voltage with energy corresponding to the bias voltage to solidify into a film. The thickness of the amorphous carbon film (DLC film) formed in the film forming process is, for example, about 1 μm. Thereby, the surface hardness of the sliding surface 2 a of the second member 2 is made higher than that of the sliding surface 1 a of the first member 1.

  As the mirror finish in the mirror finish step P2, polishing (optical polishing) is performed to finish the optically functional surface with little variation in surface scattering and local refraction with respect to light. In this case, the arithmetic average roughness Ra is preferably 10 nm or less. This mirror finishing process P2 is a polishing process, and this polishing process can be performed by a publicly known existing polishing apparatus, and the material, shape, and target arithmetic average roughness used by the second member 2 Various polishing apparatuses can be selected according to Ra.

As shown in FIG. 5, the arithmetic average roughness Ra is obtained by extracting only the reference length from the roughness curve in the direction of the average line, the X axis in the direction of the average line m of the extracted portion, and the direction of the vertical magnification. When the Y-axis is taken and the roughness curve is represented by y = f (x), the value obtained by the following formula 1 is represented by micrometers (μm) or nanometers (nm).

  As shown in FIG. 3B, the grating-like irregular structure 3 has a continuously changing height. The height difference between the irregularities of the periodic structure 3, that is, the height from the bottom of the concave portion 5 (see FIG. 3A) to the apex of the convex portion 6 (see FIG. 3A) is 50 nm or more and 500 nm or less. preferable. Moreover, it is preferable that the periodic pitch of the periodic structure 3 is 10 μm or less.

  In the wear process P3, if the sliding surface 1a of the first member 1 and the sliding surface 2a of the second member 2 are relatively slid, the periodic structure 3 of the grating-like irregularities whose height continuously changes. Is provided on the first member 1, the tip of the periodic structure is selectively worn during sliding, and the familiarity advances. At this time, fine wear powder is generated from the first member 1, but the periodic structure 3 prevents the wear powder from being caught. In addition, since the lubricant held in the periodic structure 3 quickly acts on the new surface, the periodic structure 3 having sliding traces can be worn with less disturbance. That is, the present invention is not limited to sliding conditions and can exhibit a good friction reducing action without performing high-accuracy positioning, and includes partial solid contact and elastohydrodynamic lubrication. It is possible to provide a sliding member that has low friction in a portion where a mixture exists.

  Under elastohydrodynamic lubrication (EHL), it has been reported that the oil film thickness increases by leaving a mirror surface part in the Hertz contact area of the ball specimen and arranging a periodic structure in the peripheral part of the Hertz contact area. In the manufacturing method of the sliding member of the invention, the low friction sliding surface in which the periodic structure is arranged on the peripheral portion of the Hertz contact area can be self-formed without positioning with high accuracy.

  By the way, by performing the wear process P3, in the periodic structure 3 of the first member 1, as shown in FIG. 6A, a sliding mark portion (Hertz contact area) 21 is formed by the Hertz contact portion 20. When the 1st member 1 does not rotate, as shown in FIG.6 (b), the periodic structure of a sliding trace part is worn out and the periodic structure 3 remains in the periphery of a sliding trace. Further, when the first member 1 rotates around the axis, the periodic structure remains on the periphery of the sliding trace as shown in FIG. At this time, it is preferable that the remaining size of the periodic structure perpendicular to the sliding direction is at least twice the dimension of the sliding trace perpendicular to the sliding direction. Thus, when the residual size of the periodic structure perpendicular to the sliding direction is more than twice the size of the sliding trace perpendicular to the sliding direction, the effect of increasing the oil film by the periodic structure 3 remaining at the peripheral edge of the Hertz contact area is obtained. Can be obtained efficiently. If the residual size of the periodic structure perpendicular to the sliding direction is less than twice the size of the sliding trace perpendicular to the sliding direction, the wear reduction effect due to the oil film increasing effect by the periodic structure 3 remaining at the peripheral edge of the Hertz contact area is effectively reduced. Can't get.

  In the wear process P3, the sliding direction may be a direction orthogonal to the periodic structure 3 or a direction parallel to the periodic structure 3. The direction orthogonal to the periodic structure 3 is a direction orthogonal to the longitudinal direction of each concave portion 5 of the periodic structure 3, and the direction parallel to the periodic structure 3 is the longitudinal direction of each concave portion 5 of the periodic structure 3. Parallel direction.

  As long as the sliding direction is perpendicular to the periodic structure 3, the recess 5 holding the lubricant intermittently passes through the sliding surface 2a of the second member 2, so that the oil film is prevented from being cut and less disturbed. Thus, the periodic structure 3 of the sliding trace can be worn away.

  Moreover, in the said embodiment, the 1st member 1 was comprised with the spherical body (ball), and it comprised with the flat body as the 2nd member 2. FIG. For this reason, as shown to Fig.7 (a), the curvature radius of the 2nd member 2 was infinite (infinity). However, as shown in FIGS. 7B and 7C, the absolute value of the curvature radius r1 of the sliding surface 1a of the first member 1 is larger than the absolute value of the curvature radius r2 of the sliding surface 2a of the second member 2. Even if it is small, as shown in FIG. 7D, the absolute value of the radius of curvature r1 and the absolute value of the radius of curvature r2 of the second member 2 may be the same. In FIG. 7B, the sliding surface 2a of the second member 2 is a convex curved surface, and in FIG. 7C, the sliding surface 2a of the second member 2 is a concave curved surface. Therefore, in FIG. 7B, the curvature radius r2 is +, and in FIG. 7C, the curvature radius r2 is-. Further, as shown in FIG. 7C, when the sliding surface 2a of the two members 2 is a concave curved surface, the absolute value of the radius of curvature r1 and the absolute value of the radius of curvature r2 of the second member 2 can be the same. In this case, the sliding surfaces are in close contact with each other and cannot slide relative to each other.

  If the absolute value of the radius of curvature of the sliding surface 1a of the first member 1 is equal to or less than the absolute value of the radius of curvature of the sliding surface 2a of the second member 2, the effect of increasing the oil film due to the periodic structure remaining at the peripheral edge of the Hertz contact area Can be obtained efficiently.

  Further, the irregularities of the first member 1 having the periodic structure 3 with grating-like irregularities are 50 nm or more and 500 nm or less and the periodic pitch is 10 μm or less. Since the lubricant acts on the new surface promptly, the periodic structure 3 of the sliding trace can be worn with little disturbance.

  As mentioned above, although it demonstrated per embodiment of this invention, this invention is not limited to the said embodiment, A various deformation | transformation is possible, For example, in the said embodiment, the 1st member 1 was comprised with the spherical body. However, in the periodic structure 3, the formed sliding surface 1a may be a convex curved surface, and may be a columnar shape, a cone shape or a truncated cone shape. Alternatively, the first member 1 may not rotate, or may rotate like a cam so as to slide on the sliding surface 2a of the second member 2 around its axis.

  As a laser used for the periodic structure forming step, a pulse laser such as a femtosecond laser, a picosecond laser, and a nanosecond laser can be used. Further, in the wear process P3, even if the first member 1 side is fixed and the second member 2 is slid with respect to the first member 1, conversely, the second member 2 side is fixed and the first member 1 is fixed. The first member 1 and the second member 2 may be slid with respect to the second member 2.

  In addition, the sliding direction may be parallel or orthogonal to the orientation direction of the periodic structure 3, and may be inclined at a predetermined angle (for example, about 45 degrees). Also good. Further, the sliding direction is not linear but may be circular or elliptical. The load during sliding, sliding stroke, reciprocating frequency, etc. can be arbitrarily set.

  By the way, in the processing of DLC coating, there are a plasma technique using a chemical vapor deposition (CVD) method and a physical vapor deposition (PVD) method. Therefore, in the present invention, the amorphous carbon film can be formed by various conventional methods such as plasma CVD, ionized vapor deposition, sputtering, and arc ion plating.

  Moreover, in the said embodiment, although the DLC layer was provided as the 2nd member 2, you may not provide a film in this way. That is, the periodic structure 3 of grating-like irregularities whose height continuously changes is lower in hardness than the sliding surface 2a of the second member 2, and the sliding surface 1a on which the periodic structure 3 is formed is What is necessary is that the tip of the periodic structure is selectively worn when sliding relative to the sliding surface 2a and the familiarity advances.

  The periodic structure 3 is formed over a wide range of the ball test piece as the first member 1, and the periodic structure 3 is worn away by solid contact, so that the sliding surface 1a in which the periodic structure 3 is arranged at the periphery of the Hertz contact area is self-formed. In addition, the friction characteristics were investigated.

  FIG. 2 is a schematic view of the reciprocating ball-on-plate tester used in this embodiment. An optically polished SUS440c substrate (Ra 2 nm) having an aC: H DLC film formed by plasma ion implantation was used as a plate test piece (second member 2), and the DLC film thickness was 1 μm. The ball test piece was a SUJ2 ball (Ra 8 nm) having a diameter of 6.35 mm. The ball test piece (first member 1) was irradiated with a femtosecond laser at an energy density near the processing threshold to form a grating-like periodic structure (pitch: about 700 nm, depth: about 200 nm) 3. The sliding directions were two directions orthogonal (period orthogonal SUJ2) and parallel (period parallel SUJ2) to the orientation direction of the periodic structure 3. For comparison, an unprocessed ball specimen (unprocessed SUJ2) was also used. The sliding conditions were a load of 5 N, a stroke of 20 mm, a reciprocation frequency of 0.5 Hz, and the sliding resistance up to 10,000 reciprocations was measured with a load cell. Note that PAO6 was used as the lubricant.

  The friction coefficients of various SUJ2 balls under PAO6 lubrication are shown in FIG. Although all the SUJ2 balls had a stable coefficient of friction, the periodic orthogonal SUJ2 had the lowest friction. FIG. 9 shows photographs of sliding marks of various SUJ2 balls reciprocated 10,000 times on the optical mirror surface DLC. As can be seen from FIG. 9, the unprocessed SUJ2 had the largest sliding trace and the contact portion was flattened. On the other hand, in the sliding traces of the periodic orthogonal SUJ2 and the periodic parallel SUJ2, three island-shaped regions (dark portions in the sliding traces in FIGS. 9B and 9C) with little wear were formed.

  FIG. 10 shows a 3D image of the periodic parallel SUJ2 sliding trace. Although the periodic structure at the center of the sliding mark disappeared, it was almost spherical and a groove having a width of about 10 μm was recognized between the island-like regions. The groove depth was about 350 nm for periodic orthogonal SUJ2 and about 600 nm for periodic parallel SUJ2. Since there was almost no damage on the DLC layer side, it is considered that the ball sliding trace shape reflects the elastic deformation shape.

  In an EHL test that does not involve solid contact using a ball having a periodic structure, it is reported that a satellite-like oil film is formed so as to increase the oil film thickness or sandwich a normal horseshoe-shaped EHL oil film. As shown in FIG. 11, the sliding traces of the SUJ2 ball having a satellite-like oil film and a periodic structure have a similar shape. There is a high possibility that the three island-like regions with little wear in the sliding traces were formed by the EHL oil film and the satellite-like oil film in the horseshoe shape. It can be inferred that the grooves between the island-like regions were formed by the horseshoe-shaped thin film portion contacting during reciprocating sliding. It is considered that the reduction in friction of the periodic orthogonal SUJ2 is mainly caused by the effect of increasing the EHL oil film thickness and the friction reducing effect including the familiarity of the contact portion.

DESCRIPTION OF SYMBOLS 1 1st member 1a Sliding surface 2 2nd member 2a Sliding surface 3 Periodic structure P1 Periodic structure formation process P2 Mirror surface finishing process P3 Wear process

Claims (6)

  A sliding member manufacturing method comprising a first member having a convex curved sliding surface and a second member having a sliding surface sliding relative to the sliding surface of the first member. A periodic structure forming step for forming a periodic structure of grating-like irregularities in which the convexity apex is a non-flat surface and the height continuously changes on the sliding surface of the first member; and the second member The sliding surface of the first member is mirror-finished with a higher surface hardness than the sliding surface of the first member, and the sliding surface of the first member and the sliding surface of the second member are relatively slid under lubrication. A sliding member manufacturing method, comprising: a wear step of moving the periodic structure as a sacrificial layer.   The periodic structure of the grating-like irregularities on the sliding surface of the first member remains on the periphery of the sliding trace, and the remaining periodic structure dimension perpendicular to the sliding direction is twice the sliding trace dimension orthogonal to the sliding direction. The manufacturing method of the sliding member according to claim 1, characterized in that it is as described above.   The method for manufacturing a sliding member according to claim 1, wherein the periodic structure of the grating-like irregularities is orthogonal to the sliding direction.   4. The absolute value of the radius of curvature of the sliding surface of the first member is equal to or smaller than the absolute value of the radius of curvature of the sliding surface of the second member. 5. The manufacturing method of the sliding member of description.   The periodic structure formed on the substrate surface of the first member is formed by self-organizing by irradiating a linearly polarized laser beam with an irradiation intensity in the vicinity of a processing threshold and scanning the overlapping portions in an overlapping manner. The manufacturing method of the sliding member of any one of Claims 1-4 characterized by the above-mentioned. The first member having a periodic structure of grating-like irregularities in which the height of the convex portion is a non-planar surface and the height continuously changes , and the irregularity height difference of this periodic structure is set to 50 nm to 500 nm . method for producing a sliding member according to any one of claims 1 to 5, characterized in that the periodic pitch and 10μm or less.