JP2005172082A - Sliding component and its manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a sliding component having improved lubricating performance by reliably supplying lubricant residing in a lubricant sump to a sliding portion, and to provide its manufacturing method. <P>SOLUTION: The sliding portion 33 is formed on a balance shaft 25 of a balance to be slid in the supplied state of the lubricant 40. The sliding portion 33 is constructed with a Cr coating 31 and a DLC coating 32 formed on the surface layer of a substrate 30. In the DLC coating 23, the lubricant sump 35 is formed consisting of a recessed portion 34 in which the lubricant 40 resides. An angle 41 between a side wall face 37 of the lubricant sump 35 and an outer surface 36 of the DLC coating 32 is greater than 90°, and so the lubricant 40 residing in the lubricant sump 35 to flow with the sliding motion of a connection member flows along the side wall face 37 with no interruption and then it is reliably supplied to the sliding portion 33. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a sliding component, and more particularly to a sliding component having a lubricant reservoir and a method for manufacturing the same.

  Conventionally, various devices such as a sewing machine often have a plurality of sliding parts slidably assembled. In these sliding parts, the sliding parts are prevented from being seized or worn. In order to reduce this, it is common to supply a lubricant to the sliding part or to form a coating with excellent wear resistance on the surface of the sliding part.

For example, in Patent Document 1, a DLC (diamond-like carbon) film having a low friction coefficient and a high hardness is formed as a wear-resistant film on a sliding portion of a needle bar of a sewing machine. However, when a lubricating oil is used as the lubricant, the DLC film has a property of repelling the lubricating oil, so that the lubricating oil supplied to the sliding portion flows out immediately. Therefore, in the sliding component of Patent Document 1, an oil groove is formed in the DLC film, and the lubricating oil is accumulated in the oil groove to prevent the lubricating oil from flowing out as much as possible and maintain the lubricating performance of the sliding portion. A sliding component is disclosed. In this sliding part, the lubricating oil filled in the oil reservoir easily flows in the same direction as the sliding direction by the sliding of the other sliding component, and the lubricating oil passes through the side wall surface of the oil reservoir and the DLC film Supplied to the outer peripheral surface, the lubricating performance of the sliding part is maintained in a high state.
Japanese Patent Laid-Open No. 2003-247691

  However, when the angle between the side wall surface of the oil groove and the outer peripheral surface of the DLC film is formed to be 90 ° or less, the lubricating oil that flows due to the sliding of the other sliding product is not the edge of the side wall surface of the oil groove. Therefore, the lubricating oil is hardly supplied to the sliding portion, and the lubricating performance of the sliding portion is lowered. Therefore, although the lubricating oil remains in the oil groove, the sliding portion may be seized and the durability of the sliding portion is reduced.

  SUMMARY OF THE INVENTION An object of the present invention is to provide a sliding component capable of reliably supplying a lubricant stored in a lubricant reservoir to a sliding portion to improve lubrication performance and a method for manufacturing the same.

  The invention of claim 1 has a sliding part on at least a part of the surface, and the sliding part is slid in a state where a lubricant is supplied to the sliding part. A hard coating is formed, and a lubricant reservoir for storing a lubricant is formed on the hard coating, and an angle formed between a sidewall surface of the lubricant reservoir and an outer surface of the hard coating is larger than 90 °. It is.

  According to this sliding component, the sliding component slides in a state where the lubricant is stored in the lubricant reservoir formed on the hard coating on the surface of the sliding portion. In the state where the sliding part slides, the lubricant stored in the lubricant reservoir by the other sliding part sliding on the sliding part flows in the same direction as the sliding direction of the other sliding part, The lubricant is reliably supplied to the sliding portion without being scraped off on the side wall surface of the lubricant reservoir formed with an angle formed with the outer surface of the hard coating larger than 90 °.

  According to a second aspect of the present invention, in the first aspect of the invention, the hard coating is a DLC coating. According to this sliding component, the sliding part is slid at the sliding part on which the DLC film having a high hardness and a very low friction coefficient is formed.

  According to a third aspect of the present invention, the depth of the lubricant reservoir is 20 μm or less. According to this sliding component, the supplied lubricant is stored in a shallow lubricant reservoir having a depth of 20 μm or less.

  According to a fourth aspect of the present invention, there is provided a sliding part manufacturing method in which a sliding part is formed on at least a part of a surface, and a DLC film is formed on the surface of the sliding part. When forming the lubricant reservoir, the lubricant reservoir is formed such that the angle between the side wall surface of the lubricant reservoir and the outer surface of the DLC coating is greater than 90 °.

  According to this method for manufacturing a sliding component, the DLC film is formed on the surface of the sliding portion provided on at least a part of the sliding component, and then the side wall surface of the lubricant reservoir and the outer surface of the DLC coating are A part of the DLC film is etched to form a lubricant reservoir so that the angle is greater than 90 °, and a sliding component is manufactured.

  According to a fifth aspect of the invention, in the invention of the fourth aspect, the DLC film is etched by oxygen plasma when the lubricant reservoir is formed. According to this method for manufacturing a sliding component, all the DLC films in the portion where the lubricant reservoir is formed are simultaneously etched by oxygen plasma.

  According to a sixth aspect of the invention, in the fifth aspect of the invention, an etching gas containing oxygen and carbon tetrafluoride is used when forming the lubricant reservoir. According to this method for manufacturing a sliding component, the surface of the DLC film is treated with hydrofluoric acid generated from carbon tetrafluoride and etched with oxygen plasma.

  According to a seventh aspect of the present invention, in the sixth aspect of the invention, the etching gas used for forming the lubricant reservoir has an oxygen volume concentration of less than 60%. According to this method for manufacturing a sliding component, when the volume concentration of oxygen in the etching gas is 60% or more, the DLC film is over-etched and the angle between the side wall surface of the lubricant reservoir and the outer surface of the sliding portion is 90. A lubricant reservoir of less than 0 ° is formed, but by making the volume concentration of oxygen in the etching gas less than 60%, the angle is larger than 90 ° by oxygen plasma without over-etching the DLC film. A lubricant reservoir is formed.

  The invention of claim 8 is the invention of claim 6, wherein the volume concentration of carbon tetrafluoride is less than 6% in the etching gas used for forming the lubricant reservoir. According to this method for manufacturing a sliding component, when the volume concentration of carbon tetrafluoride in the etching gas is set to 6% or more, the DLC film is over-etched, and the side wall surface of the lubricant reservoir and the outer surface of the sliding portion are separated. A lubricant reservoir having an angle of 90 ° or less is formed. By reducing the volume concentration of carbon tetrafluoride in the etching gas to less than 6%, the DLC film is not over-etched, and the angle is increased by oxygen plasma. A lubricant reservoir is formed which is greater than 90 °.

  According to a ninth aspect of the invention, in the invention of the fourth aspect, when the lubricant reservoir is formed, the DLC film is etched by a focused ion beam or a laser. According to this method for manufacturing a sliding part, the DLC film in the portion where the lubricant reservoir is formed is etched by a focused ion beam or laser.

  According to the first aspect of the present invention, the lubricant retention performance is improved by forming the lubricant reservoir, and the angle formed between the sidewall surface of the lubricant reservoir and the outer surface of the hard coating is 90 ° or more. Therefore, the lubricant that flows due to the sliding of the other sliding part flows along the side wall surface of the lubricant reservoir without being scraped off by the side wall surface of the lubricant reservoir, and is thus stored in the lubricant reservoir. The lubricant can be reliably supplied to the sliding portion, the lubricating performance can be enhanced, and the durability of the sliding component can be enhanced.

  According to the invention of claim 2, since the DLC film having a high hardness and a very low friction coefficient is formed on the sliding portion, the durability and wear resistance of the sliding component can be improved.

  According to the invention of claim 3, by setting the depth of the lubricant reservoir to 20 μm or less, the lubricant can be reliably supplied to the surface of the sliding portion even with a small amount of lubricant stored in the lubricant reservoir. it can.

  According to the fourth aspect of the present invention, the sliding component manufactured by this sliding component manufacturing method has the same effect as the first aspect.

  According to invention of Claim 5, since a DLC film is etched by oxygen plasma, many areas can be etched at once, and manufacturing time can be shortened.

  According to the sixth aspect of the present invention, the surface of the DLC film can be treated with hydrofluoric acid generated from carbon tetrafluoride by etching with an etching gas containing carbon tetrafluoride. Can be shortened.

  According to the invention of claim 7, by making the volume concentration of oxygen in the etching gas less than 60%, the angle between the side wall surface of the lubricant reservoir and the outer surface of the sliding portion is surely larger than 90 °. Can be formed.

  According to the invention of claim 8, by making the volume concentration of carbon tetrafluoride in the etching gas less than 6%, the angle between the side wall surface of the lubricant reservoir and the outer surface of the sliding portion is surely 90 °. Larger than that.

  According to the invention of claim 9, by adjusting the intensity or irradiation time of the focused ion beam or laser for etching the DLC film, or the incident angle to the DLC film, the side wall surface of the lubricant reservoir and the sliding portion The angle with the outer surface can be accurately formed at a desired angle larger than 90 °. Further, since the step of masking the DLC film necessary for etching by plasma etching or the like can be omitted, the manufacturing process can be simplified.

  The invention of the present application provides a sliding part having a sliding part on at least a part of a surface and sliding the lubricant in a state where a lubricant is supplied to the sliding part. The hard coating is formed with a lubricant reservoir for storing a lubricant, and an angle formed between a side wall surface of the lubricant reservoir and an outer surface of the hard coating is formed to be greater than 90 °. And a method for manufacturing the sliding component.

  Embodiments of the present invention will be described below with reference to the drawings. This embodiment is an example in which the present invention is applied to a balance of a two-needle sewing machine. In the following description, front, rear, left and right are defined as shown in FIG. First, the two-needle sewing machine 1 will be briefly described. As shown in FIG. 1, the two-needle sewing machine 1 includes a bed portion 2 that is long in the left-right direction, a leg column portion 3 that extends upward from the right end portion of the bed portion 2, and a bed portion 2 that faces the bed column 2. The arm part 4 extended to the left is provided.

  As shown in FIG. 1, a main shaft 10 is disposed in the left-right direction inside the arm portion 4, and a needle bar swinging shaft 11 is disposed substantially parallel to the main shaft 10 below the main shaft 10. Yes. The right end portion of the main shaft 10 protrudes from the arm portion 4 to the outside, and a manual pulley 12 is provided at the protruding portion. The main shaft 10 is rotationally driven by a sewing machine motor (not shown).

  As shown in FIGS. 1 and 2, the arm head at the left end portion of the arm portion 4 includes a crank 13, a crank lever 14, a needle bar holder 15, a needle bar 16, a needle bar support member 17, A balance mechanism 19 having a balance 18 is provided.

  The crank 13 is fixed to the left end portion of the main shaft 10 and is rotated together with the main shaft 10. A head portion 14 a of the crank lever 14 is rotatably connected to a connecting shaft 13 a extending leftward from the crank 13, and a lower end portion of the crank lever 14 is rotatably connected to a needle bar holder 15. The needle bar 16 is formed in a columnar shape, and a needle bar holder 15 is fixed to the middle step part thereof, and is supported by the upper end part and the lower end part of the needle bar support member 17 so as to be slidable. The lower end portion of the needle bar 16 projects downward from the sewing machine frame of the arm portion 4, and the two needles 21 are attached.

  Accordingly, when the rotational driving force of the sewing machine motor is transmitted to the crank 13 via the main shaft 10, the rotational driving force is transmitted to the needle bar holder 15 via the crank lever 14, and the needle bar holder 15 is moved to the needle bar 16. The needle bar 16 is driven to swing in the front-rear and horizontal directions together with the needle bar support member 17 by driving the needle bar swinging shaft 11 to swing back and forth.

  As shown in FIG. 2, the balance mechanism 19 includes a balance (corresponding to a sliding part) 18, a connecting member 22, and a rotation shaft 23 that supports the balance 18 on a sewing machine frame so as to be rotatable. The connecting member 22 is rotatably connected to the left end portion of the head portion 14 a of the crank lever 14, and is slidably supported on the balance shaft 25. The balance 18 has a cylindrical balance shaft 25 at the lower end and a balance portion 26 on which an upper thread is hung. As shown in FIGS. 3 and 4, the balance shaft 25 has a structure in which a Cr (chrome) coating 31 and a DLC coating 32 are formed on the surface layer portion of a steel cylindrical rod-shaped substrate 30. The Cr coating 31 and the DLC coating 32 correspond to hard coatings.

  In order to prevent the DLC film 32 from being peeled off from the surface of the base material 30, the Cr film 31 is formed at a thickness of about 0.5 μm on the portion of the surface of the base material 30 that becomes the sliding portion 33. Yes. Since this Cr coating 31 remains unremoved even if a part of the DLC coating 32 is removed to form the lubricant reservoir 35 as will be described later, the substrate 30 can be protected from oxidation, breakage, and the like. it can.

  The DLC film 32 is formed on the surface of the Cr film 31 with a thickness of about 5 μm. The DLC film 32 can be adjusted in hardness according to the hydrogen content at the time of film formation, and the HV (Vickers hardness) can be formed into a high hardness film of about 8000, which is close to HV of diamond, from several hundreds. In this embodiment, the DLC film 32 having a hardness of HV1000 or higher, which is higher than the Cr film 31 (HV200) and the base material 30 (HV600 by carburizing and quenching) is formed. The coefficient of friction of the DLC film 32 is about 0.1 or less, and is a very excellent film in wear resistance and slidability. The thicknesses of the Cr coating 31 and the DLC coating 32 are merely examples, and may be smaller or larger than the above values.

  As shown in FIGS. 3 and 4, the DLC film 32 is provided with a lubricant 40 made of lubricating oil, and the lubricant composed of a recess 34 penetrating to the Cr film 31 in order to enhance the retention performance of the lubricant 40. A reservoir 35 is formed. The plurality of recesses 34 are arranged so as to have a pattern that is shifted by a predetermined height in the vertical direction (axial direction) at intervals of 90 ° in the circumferential direction. Each recess 34 is formed in a rhombus shape and has a depth of about 5 μm which is the same as the thickness of the DLC film 32.

  The side wall surface 37 of each recess 34 is formed at about 120 ° with respect to the outer surface 36 of the DLC coating 32. Thus, the supplied lubricant 40 is stored in the lubricant reservoir 35 by forming the angle 41 between the side wall surface 37 of the recess 34 and the outer surface 36 of the DLC coating 32 to be larger than 90 °. When the connecting member 22 slides on the sliding portion 33, the lubricant 40 flowing in the sliding direction by the sliding of the connecting member 22 flows along the side wall surface 37 without stopping the flow on the side wall surface 37. The lubricant 40 is reliably supplied to the sliding portion 33. The angle 41 is not limited to 120 °, and may be formed larger than 90 °. The angle 41 is appropriately determined depending on the viscosity of the lubricant 40, the depth of the recess 34, the sliding speed, the installation angle of the balance 18, and the like. It can be changed.

  According to the balance mechanism 19, when the crank 13 is rotated by the rotational driving force of the sewing machine motor, the connecting shaft 13 a of the crank 13 is rotated along the circular orbit A shown in FIG. 2 together with the head portion 14 a and the connecting member 22. By this rotational drive, the connecting member 22 is guided by the balance shaft 25 and reciprocated in the substantially vertical direction, and by this reciprocation drive, the balance 18 is driven to swing around the rotation shaft 23 and the upper thread is tightened.

  Next, with reference to FIGS. 5 and 6, a method for manufacturing the balance 18, particularly the balance shaft 25 will be described. First, the base material 30 of the steel balance 18 is manufactured, the Cr film 31 is formed on the surface of the base material 30 of the balance shaft 25, and the DLC film is formed on the surface of the Cr film 31. 32 is continuously formed in a vacuum by UBM sputtering (see FIG. 5-1). Specifically, first, sputtering is performed using Cr as a target, and a Cr coating 31 is formed to a predetermined thickness. Next, while sputtering of Cr is continued, sputtering using graphite as a target is performed in parallel. Then, the sputtering rate of Cr with respect to the graphite is gradually decreased, and the sputtering rate of graphite is gradually increased, so that the DLC coating 32 is formed on the surface of the Cr coating 31.

Next, as shown in FIG. 6, an aluminum masking member 47 having a diamond-shaped hole 46 formed on the balance shaft 25 on which the Cr coating 31 and the DLC coating 32 are formed is externally fitted in a substantially close contact manner (FIG. 5). -2). Next, the masked balance 18 is introduced into a chamber where etching is performed. Next, the inside of the chamber is set to a humidity of 50% and an atmospheric pressure of 760 Torr. Further, the inside of the chamber is reduced to 0.05 Torr, and an etching gas composed of oxygen, carbon tetrafluoride (CF ₄ ), argon or the like is put into the chamber. Introduce. Next, oxygen in the etching gas is turned into plasma, and the surface of the DLC film 32 exposed from the masking member 47 is treated with carbon tetrafluoride until the Cr film 31 is exposed to oxygen plasma by the DLC film 32. Plasma etching is performed for 60 minutes to form the lubricant reservoir 35 in which the angle 41 between the sidewall surface 37 of the lubricant reservoir 35 and the outer surface 36 of the DLC coating 32 is greater than 90 ° (see FIG. 5-3). Finally, the balance 18 is taken out from the chamber, the masking member 47 is removed, and the balance shaft 25 of the balance 18 is completed (see FIG. 4).

  Next, when the DLC film 32 is subjected to plasma etching, the volume concentration of oxygen or carbon tetrafluoride in the etching gas, the side wall surface 37 of the recess 34 etched by the etching gas, and the outside of the DLC film 32 are etched. The angle 41 with the surface 36 will be described quantitatively.

  First, an experiment in which the volume concentration of oxygen in the etching gas is changed will be described with reference to FIG. In this experiment, the volume concentration of oxygen is changed between 43% and 70% with the gas pressure in the chamber where etching is performed being 0.28 Torr and the volume concentration of carbon tetrafluoride being 3.7%. I went. As shown in FIG. 7, when the volume concentration of oxygen is 43% and 55%, the angle 41 is formed at 140 ° and 110 °. However, when the concentration is 60%, the angle 41 is formed at 90 °, and when the concentration is 70%, the DLC film 32 is over-etched to form the angle 41 at 70 °, that is, as shown in FIG. Thus, the angle 41A is formed to be 90 or less, and the lubricant 40 is less likely to flow out of the lubricant reservoir 35A. Therefore, in order to prevent over-etching and to form the angle 41 larger than 90 ° by plasma etching, it is desirable that the volume concentration of oxygen be 60% or less.

  Next, an experiment in which the volume concentration of carbon tetrafluoride in the etching gas is changed will be described. In this experiment, the volume concentration of carbon tetrafluoride is between 3.7% and 7.3% with the gas pressure in the chamber where etching is performed being 0.28 Torr and the volume concentration of oxygen being 43%. It was changed with. As shown in FIG. 8, when the volume concentration of carbon tetrafluoride is 3.7% and 5%, the angle 41 is formed at 140 ° and 130. However, when the concentration is 6%, the angle 41 is formed at 90 °, and when the concentration is 7.3%, the DLC film 32 is over-etched and the angle 41 is formed at 45 °. 9, the angle 41A is formed to be 90 ° or less, and the lubricant 40 is less likely to flow out of the lubricant reservoir 35A. Therefore, in order to prevent over-etching and to form the angle 41 larger than 90 ° by plasma etching, it is desirable that the volume concentration of carbon tetrafluoride is 6% or less. 9 described above is not an example of the present invention but a comparative example.

  Next, the operation and effect of the above-described balance 18, particularly the balance shaft 25 will be described.

  According to the balance shaft 25, since the lubricant reservoir 35 is formed, the retention performance of the lubricant 40 can be enhanced. Furthermore, since the angle 41 between the side wall surface 37 of the lubricant reservoir 35 and the outer surface 36 of the DLC coating 32 is formed to be larger than 90 °, the lubricant 40 filled in the lubricant reservoir 35 is connected to the connecting member 22. The lubricant 40 flows along the side wall surface 37 of the lubricant reservoir 35 without being scraped off by the lubricant reservoir 35, so that the lubricant 40 flows outside the DLC coating 32. Since it is reliably supplied to the surface, the lubrication performance can be improved. Since the sliding part 33 of the balance shaft 25 is covered with the DLC film 32 having a high hardness and a very low friction coefficient, durability and wear resistance can be improved.

  In the method of manufacturing the balance shaft 25, when the DLC film 32 is subjected to plasma etching, the volume concentration of oxygen in the etching gas is set to less than 60% or the volume concentration of carbon tetrafluoride is set to less than 6%. 32 can be prevented, and the angle 41 between the side wall surface 37 of the lubricant reservoir 35 and the outer surface 36 of the DLC coating 32 can be reliably formed to be larger than 90 °. A large area can be etched at once by etching the DLC film 32 with oxygen plasma, and the surface of the DLC film 32 is treated with hydrofluoric acid generated by carbon tetrafluoride contained in an etching gas. Therefore, the time required for etching can be greatly reduced.

  Next, a modified example in which the above-described embodiment is partially modified will be described.

  1) The shape of the recess 34 of the lubricant reservoir 35 in the above-described embodiment can be changed to various shapes. For example, as shown in FIGS. 10 and 11, the DLC films 32a and 32b may be formed so that the side wall surfaces 37a and 37b of the recesses 34a and 34b are curved. In this case, the tangents at the upper ends of the side wall surfaces 37a and 37b and the outer surfaces 36a and 36b of the DLC films 32a and 32b are formed so as to be 90 ° or more. Further, as shown in FIG. 12, the upper portion of the side wall surface 37c of the recess 34c is formed to be 90 ° or more with the outer surface 36c of the DLC coating 32c, and the lower portion of the side wall surface 37c is outside the DLC coating 32c. You may form so that it may become substantially 90 degrees with respect to the surface 36c.

  2) In the above-described embodiment, the concave portion 34 is formed in a diamond shape, but various shapes such as a circular shape, a rectangular shape, a triangular shape, or a continuous shape such as a lattice shape or a groove shape are applied. be able to. However, when the recess is formed in a groove shape, if the length of the groove is increased, the lubricant easily flows and flows out along the groove, and it is difficult to improve the lubricity. Further, the depth of the recess 34 is not limited to 5 μm, but the depth of the recess is preferably 20 μm or less in consideration of the supply of lubricant. Furthermore, although the concave portions are formed periodically at regular intervals, they may be formed non-periodically at different intervals.

  3) In the embodiment described above, the Cr coating 31 is formed between the base material 30 and the DLC coating 32. However, the Cr coating 31 is not necessarily required and may be omitted. However, in such a configuration, it is desirable to form a lubricant reservoir by etching the DLC film to such an extent that the base material is not exposed, and to protect the base material from rust and breakage by the DLC film.

  4) Instead of the Cr coating 31 in the above-described embodiment, a W (tungsten) coating, a Ti (titanium) coating, a Si (silicon coating), a Ni (nickel) coating, or the like may be applied.

  5) In the above-described embodiment, the DLC film 32 is plasma etched until the Cr film 31 is exposed. However, the DLC film may be etched to the extent that the Cr film is not exposed to form a lubricant reservoir in the DLC film. .

  6) In the above-described embodiments, the lubricating oil is applied as the lubricant 40. However, the lubricant is not limited to the lubricating oil, and nano-level particles may be applied. In this case, particles such as silicon oxide (diameter: about 10 to 40 nm), titanium oxide (diameter: about 20 nm), aluminum oxide (diameter: 10 nm) can be applied.

  7) In the above-described embodiments, the DLC film 32 is formed by UBM sputtering. However, the DLC film may be formed by a physical vapor deposition method other than UBM sputtering or a chemical vapor deposition method such as a CVD method.

  8) In the embodiment described above, the DLC film 32 is etched by oxygen plasma, but the lubricant reservoir may be formed by etching the DLC film by a focused ion beam or laser. In order to form the lubricant reservoir so that the angle between the side wall surface of the lubricant reservoir and the outer surface of the hard coating becomes larger than 90 ° by the focused ion beam or laser, for example, the following three etching methods are used. Can be considered.

  8-1) The intensity of the focused ion beam or laser is decreased at the outer peripheral portion of each concave portion of the lubricant reservoir, and the strength is gradually increased while the focused ion beam or laser is directed toward the center of each concave portion of the lubricant reservoir. Is moved to etch the DLC film, and the angle between the side wall surface of the lubricant reservoir and the outer surface of the hard film can be formed larger than 90 °.

  8-2) At the outer periphery of each recess of the lubricant reservoir, the focused ion beam or laser is shortened, and the time is gradually increased while the focused ion beam or laser is moved to the center of each recess of the lubricant reservoir. The angle between the sidewall surface of the lubricant reservoir and the outer surface of the hard coating can be formed to be larger than 90 ° by etching the DLC coating.

  8-3) A focused ion beam or laser is incident on the surface of the DLC film at a desired angle (for example, 120 °), and the DLC film is etched, so that the side of the lubricant reservoir is at the same angle as the incident angle. An angle between the wall surface and the outer surface of the DLC coating can be formed.

9) Although the etching gas containing carbon tetrafluoride is applied in the above-described embodiments, C ₂ F ₆ , CHF ₃ , C ₂ F ₈ , and SF ₆ may be applied instead of carbon tetrafluoride. Good. In this case, in order to form the angle between the side wall surface of the lubricant reservoir and the outer surface of the hard coating larger than 90 °, the concentration of fluorine atoms in the unit volume is set to the above-described fluorine atom of carbon tetrafluoride. It is necessary to set the same range as the concentration in the unit volume. For example, in the case of C ₂ F ₆ ,
(Volume concentration of C ₂ F ₆ ) × (number of fluorine atoms in C ₂ F ₆ molecule (= 6))
≦ (maximum volume concentration of carbon tetrafluoride) × (number of fluorine atoms in carbon tetrafluoride molecule (= 4))
From
(Volume concentration of C ₂ F ₆ ) ≦ 6% × (4/6) = 4%
It becomes. That is, when C ₂ F ₆ is used instead of carbon tetrafluoride, the volume concentration of C ₂ F ₆ is desirably less than 4%. However, the number of molecules of C ₂ F ₆ and carbon tetrafluoride contained in the same volume is the same.

  In addition to the sewing machine balance, the present invention can be applied to sliding parts of various machines. Further, the sliding portion is not limited to a sliding portion that slides linearly, and includes a sliding portion that slides by a rotational motion. The present invention is not limited to the embodiments described above, and those skilled in the art can implement the present invention by adding various modifications to the embodiments without departing from the spirit of the present invention. Includes those modifications.

It is a perspective view which shows the internal mechanism in the arm part of the 2 needle | hook sewing machine which concerns on the Example of this invention. It is a left view which shows the said internal mechanism. It is a principal part enlarged view of a balance shaft and its lubricant reservoir. It is a principal part expanded sectional view of a balance shaft and its lubricant reservoir. It is the principal part enlarged view which formed the Cr film and the DLC film in the base material in the middle of balance manufacture. It is the principal part enlarged view which made the masking member fit on the balance axis | shaft in the middle of balance manufacture. It is the principal part expanded sectional view which etched the DLC film in the middle of balance manufacture. It is a figure which shows a balance axis and a masking member. It is a table | surface of the experimental result which shows the relationship between the volume concentration of oxygen in etching gas, the angle of the side wall surface of a lubricant reservoir, and the outer surface of a DLC film. FIG. 6 is a view corresponding to FIG. 5 regarding the volume concentration of carbon tetrafluoride in an etching gas. FIG. 5 is a diagram corresponding to FIG. 4 of a comparative example in an over-etched state. FIG. 5 is a view corresponding to FIG. 4 showing a first modification example. FIG. 5 is a view corresponding to FIG. 4 showing a second modification example. FIG. 9 is a diagram corresponding to FIG. 4 and showing a third modification example.

Explanation of symbols

18 Balance 25 Balance shaft 30 Base material 31 Cr coating 32 DLC coating 33 Sliding part 35 Lubricant reservoir 36, 36a, 36b, 36c Outer surface 37, 37a, 37b, 37c Side wall surface 40 Lubricant 41 Angle

Claims (9)

In a sliding component that has a sliding part on at least a part of the surface and is slid in a state where a lubricant is supplied to the sliding part,
A hard coating is formed on the surface of the sliding part,
The hard coating is formed with a lubricant reservoir in which a lubricant is stored,
A sliding part characterized in that an angle formed between a side wall surface of the lubricant reservoir and an outer surface of the hard coating is formed to be larger than 90 °.   The sliding component according to claim 1, wherein the hard coating is a DLC coating.   The sliding component according to claim 1 or 2, wherein a depth of the lubricant reservoir is 20 µm or less. In a manufacturing method of a sliding part having a sliding part on at least a part of the surface and forming a DLC film on the surface of the sliding part,
When the lubricant reservoir is formed by etching a part of the DLC coating, the lubricant reservoir is formed so that the angle between the side wall surface of the lubricant reservoir and the outer surface of the DLC coating is greater than 90 °. A method for manufacturing a sliding component, characterized in that:   The method for manufacturing a sliding component according to claim 4, wherein the DLC film is etched by oxygen plasma when the lubricant reservoir is formed.   6. The method for manufacturing a sliding component according to claim 5, wherein an etching gas containing oxygen and carbon tetrafluoride is used when forming the lubricant reservoir.   The method for manufacturing a sliding part according to claim 6, wherein the etching gas used for forming the lubricant reservoir has an oxygen volume concentration of less than 60%.   The method for manufacturing a sliding part according to claim 6, wherein the etching gas used for forming the lubricant reservoir has a volume concentration of carbon tetrafluoride of less than 6%. 5. The method for manufacturing a sliding part according to claim 4, wherein the DLC film is etched by a focused ion beam or a laser when the lubricant reservoir is formed.

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