JP4745604B2 - Sliding part manufacturing method and sliding part - Google Patents

Description

  The present invention relates to a sliding part manufacturing method and a sliding part, and more particularly to a sliding part manufacturing method and a sliding part capable of easily forming an oil reservoir for extending the seizure life.

  Conventionally, various devices such as a sewing machine have been slidably assembled with a plurality of sliding parts. In these sliding parts, seizure of the sliding parts is prevented and wear is reduced. Therefore, it is common to supply a lubricant to the sliding part or to form a coating with high wear resistance on the surface of the sliding part.

  For example, in Patent Document 1, a DLC film (diamond-like carbon film) having a low friction coefficient and a high hardness is formed as a wear-resistant film on the sliding portion of the needle bar. This wear-resistant film is formed on the surface of the sliding portion by physical vapor deposition such as UBM sputtering (unbalanced magnetron sputtering) or chemical vapor deposition such as CVD (chemical vapor deposition).

Furthermore, in Patent Document 1, in order to improve wear resistance, an aluminum alloy material having a good compatibility with the DLC film is formed on the sliding portion of the needle bar support member that slidably supports the needle bar. . This aluminum alloy material improves the wear resistance of the DLC film by preventing the bond between the dangling bond of the DLC film and hydrogen at the terminal thereof, and preventing the DLC film from being graphitized.
JP 2003-111990 A

  However, even if the sliding part is constituted by a DLC film as in Patent Document 1, the lubricating oil supplied to the sliding part is indispensable, but the surfaces of the sliding part and the sliding part are smooth. The lubricating oil cannot be held on the sliding part, and the sliding part will be seized in a short time (for example, less than 1000 hours) from the supply of the lubricating oil, and the operator must supply the lubricating oil frequently. I must. In particular, there are multiple sliding parts on the sewing machine, and they are often places where lubricating oil cannot be easily supplied, and it is very wasteful labor and time for operators to supply lubricating oil frequently. Will be. Therefore, it is conceivable to form an oil reservoir such as a groove in the DLC film so that the lubricating oil does not flow out immediately. However, since the DLC film is formed with a thickness of about several μm, the above irregularities are formed by machining such as cutting. It is very difficult to form accurately.

  SUMMARY OF THE INVENTION An object of the present invention is to provide a sliding part manufacturing method capable of easily forming an oil reservoir for improving the lubricating oil supply cycle and extending the baking life, and a sliding component having the oil reservoir.

Invention of Claim 1 has a sliding part in at least one part of the surface of a base material, The manufacturing method of the sliding part which formed the DLC film in the surface of the said sliding part WHEREIN: The said sliding component is the said a component attached to the sewing machine constitutes a sliding portion as a reciprocating sliding portion, wherein a masking member which masks a part of the surface of the DLC film and an inner diameter that can fitted on the sliding portion, double a masking step of and removably fitted in a substantially close contact shape masking member of cylindrical shape arranged in a straight line on the surface of the DLC film to the sliding direction through holes in the number of the same shape at regular intervals, the An etching process for etching the portion of the DLC film that is not masked by the masking member, and a process for removing the masking member from the sliding portion after the etching process are provided.

In the method for manufacturing a sliding component having a sliding part on at least a part of the surface of the base material, in the DLC film forming step, a DLC film having wear resistance and high hardness is formed on the surface of the sliding part by physical vapor deposition or is formed by a chemical vapor deposition, the masking step, an inner diameter of which can be fitted to the sliding portion of the masking member which masks a part of the surface of the DLC film formed on the sliding portion, through the multiple isomorphous formed into a cylindrical shape holes are arranged linearly in the sliding direction at predetermined intervals, the masking member is externally fitted and detachably in a substantially close contact pattern on the front surface of the DLC film, the etching step, The portion of the DLC film that is not masked by the masking member is etched away.

  According to a second aspect of the present invention, in the first aspect of the invention, in the etching step, a concave portion is formed by etching in the region of the sliding portion. In the etching step, the DLC film that is not masked by etching is removed to form a recess.

  According to a third aspect of the present invention, in the second aspect of the present invention, a recess as an oil reservoir is formed in the etching step. In the etching process, the DLC film is removed by etching to form a recess that is an oil reservoir.

  According to a fourth aspect of the present invention, in the second or third aspect of the present invention, in the etching step, the concave portion is formed in an area ratio of 14% to 70% with respect to a surface area of the sliding portion. In the etching step, 14% to 70% of the surface area of the DLC film formed on the surface of the sliding portion by etching is removed to form a recess.

  According to a fifth aspect of the present invention, in the first to fourth aspects of the present invention, before the step of forming the DLC film on the surface of the sliding portion, a metal film forming step of forming a metal film on the surface of the substrate is performed. It is provided. In this sliding component manufacturing method, a metal film is formed on the surface of the substrate in the metal film forming step, and a DLC film is formed on the surface of the metal film in the DLC film forming step.

  In a sixth aspect of the present invention, in the fifth aspect of the invention, in the etching step, the DLC film is etched until the metal film appears on the surface. According to this method for manufacturing a sliding component, in the etching process, the portion of the DLC film that is not masked by etching is removed, and the metal film is exposed.

  According to a seventh aspect of the present invention, in the first to sixth aspects of the invention, in the masking step, each exposed area on the surface of the DLC film is circular. Therefore, when the DLC film is removed in the etching process, a circular recess is formed.

  The invention according to claim 8 is the invention according to claims 1 to 7, wherein the DLC film is removed by plasma etching in the etching step. In the etching process, plasma etching using oxygen plasma or the like is performed to remove the DLC film as carbon monoxide and carbon dioxide.

  The invention according to claim 9 is the invention according to claim 8, wherein the substrate is made of a steel material, and the plasma etching is performed at 150 ° C. or less. In the etching step, plasma etching is performed at a base material made of a steel material at 150 ° C. or lower.

  The invention of claim 10 is the invention of claims 1 to 7, wherein the DLC film is removed by laser etching in the etching step. In the etching process, laser etching using a femtosecond laser, an ultraviolet laser, an excimer laser, or the like is performed to remove the DLC film.

  The invention of claim 11 is a sliding component manufactured by the invention of claims 1 to 10.

  In this sliding component, when lubricating oil is supplied, the DLC film is stored in an oil reservoir that is a recess formed so as to penetrate to the metal film.

  Further, in this sliding component, the lubricating oil is held substantially evenly in a plurality of oil reservoirs having the same shape arranged in a predetermined pattern.

  According to a twelfth aspect of the invention, in the invention of the eleventh aspect, the sliding component is a balance having a sewing machine balance shaft. In this sliding component, a balance having a scale shaft of the sewing machine is attached to the sewing machine and slid back and forth to tighten the upper thread.

According to the present invention, since the DLC film not masked by the masking member is removed by ET etching to form a recess which is the oil reservoir, it is possible to easily form the oil reservoir. By forming the masking member in a desired shape, the recess can be formed in the desired shape. By etching, only the DLC film can be easily removed without damaging the substrate. Further, by forming the oil reservoir, the lubricating oil can be prevented from flowing out for a long period of time, the lubricating oil supply cycle can be extended, and the seizure life can be improved. Furthermore, high-speed sewing or long-time sewing can be performed by supplying the lubricating oil once, and high-speed reciprocating sliding or long-time reciprocating sliding can be performed by supplying the lubricating oil once. In addition, since the plurality of concave portions having the same shape are formed at regular intervals, the supplied lubricating oil is evenly accumulated over the entire area of the sliding portion, so that partial baking can be prevented.

  According to the invention of claim 2, the same effect as that of claim 1 can be obtained.

  According to the invention of claim 3, the same effect as that of claim 1 can be obtained.

  According to the fourth aspect of the present invention, since the concave portion which is an oil reservoir is formed at an area ratio of 14% to 70% with respect to the surface area of the sliding portion, the seizure life due to one supply of lubricating oil is greatly extended. be able to.

  According to invention of Claim 5, even if a DLC film is removed by an etching, since a metal film is not removed, it can prevent that a base material is exposed.

  According to invention of Claim 6, even if a DLC film is removed, since the surface of a base material is protected by a metal film, a base material can be protected from deterioration by rust etc.

  According to the seventh aspect of the present invention, since the recesses are all circular, the supplied lubricating oil is less likely to be biased within each recess, so that partial baking can be further prevented.

  According to the invention of claim 8, by performing plasma etching with oxygen plasma that reacts only with the DLC film, the DLC film is not damaged without damaging the substrate or the metal film formed between the substrate and the DLC film. Only the coating can be removed.

  According to the ninth aspect of the invention, since the plasma etching is performed while maintaining the base material to be quenched at about 250 ° C. at 150 ° C. or lower, deformation of the base material in the plasma etching can be prevented.

  According to the invention of claim 10, the same effects as those of claims 1 to 7 can be obtained.

  According to the invention of claim 11, since the sliding component is manufactured by the manufacturing method according to any one of claims 1 to 10, the same effects as those of claims 1 to 10 can be obtained.

  According to the invention of claim 12, it is possible to pull up the thread at the time of high-speed sewing or pull up the thread at the time of sewing for a long time by supplying the lubricating oil once.

  The object of the present invention is to provide a sliding part manufacturing method capable of easily forming an oil reservoir capable of improving the supply cycle of the lubricating oil and extending the seizure life, and a sliding component having the oil reservoir. This was achieved by partially removing the DLC film formed on the surface of the sliding portion by plasma etching to form an oil reservoir.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. The present embodiment is an example in which the present invention is applied to a method of manufacturing a balance having a balance shaft in which a sliding portion is formed on a part of the surface of a base material of a balance of a two-needle sewing machine and the balance. In the following description, as shown in FIG. 1, the direction in which the worker is located is defined as the front, and the left and right as viewed from the worker are defined as the left and right.

  First, the two-needle sewing machine will be briefly described. As shown in FIG. 1, the two-needle sewing machine M has a bed portion 1 that is long in the left-right direction, a leg column portion 2 that extends upward from the right end portion of the bed portion 1, and the leg column portion 2 that faces the bed portion 1. The arm part 3 extended to the left is provided.

  A main shaft 10 facing in the left-right direction is disposed inside the arm portion 3, and a needle bar swinging shaft 11 facing in the left-right direction is disposed below the main shaft 10. A right end portion of the main shaft 10 protrudes from the arm portion 3 to the outside, and a pulley 12 is fixed to the protruding portion. The main shaft 10 is rotationally driven by a pulley 12 or a sewing machine motor (not shown).

  As shown in FIGS. 1 and 2, the left end portion of the arm portion 3 has a crank 13, a crank lever 14, a needle bar holder 15, a needle bar 16, a needle bar support member 17, and a balance 18. A balance mechanism 19 is provided. The crank 13 is fixed to the left end portion of the main shaft 10 and is driven to rotate 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 forward 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 at the center, and is supported by the upper and lower ends of the needle bar support member 17 so as to be slidable.

  The lower end portion of the needle bar 16 protrudes downward from the arm portion 3, and the two needles 21 are attached. When the rotational drive 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 includes the needle bars 16 and two. It is reciprocated up and down together with the needle 21. Further, the needle bar 16 is driven to swing in the front-rear and horizontal directions together with the needle bar support member 17 when the needle bar swinging shaft 11 is rotationally driven.

  As shown in FIG. 2, the balance mechanism 19 includes a balance 18, a connecting member 22, and a rotation shaft 23 that supports the balance 18 on a two-needle sewing machine M so as to be rotatable. The balance 18 includes a cylindrical balance shaft 25 at a lower end portion and a balance portion 26 on which an upper thread is hung. As shown in FIGS. 3 and 4, the balance shaft 25 includes a columnar base material 27 made of a steel material, and a Cr coating 29 formed on the surface of the base material 27 at a position corresponding to the sliding portion 28. And a DLC coating 30 formed on the surface of the Cr coating 29, and an oil reservoir 32 comprising a plurality of recesses 31 formed in the DLC coating 30 so as to penetrate to the Cr coating 29.

  The plurality of recesses 31 constituting the oil reservoir 32 are formed so that the DLC film 30 is partially removed by plasma etching and the Cr film 29 is exposed. The oil sump 32 is arranged based on a predetermined pattern in which a plurality of circular recesses 31 having the same shape are arranged at regular intervals in the vertical direction and are spaced at 90 ° intervals in the circumferential direction and at a certain height in the vertical direction. Has been. The connecting member 22 is formed in a cylindrical shape, is rotatably connected to the rear end portion of the crank lever 14, and is slidably fitted to the balance shaft 25.

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

  Next, the manufacturing method of the balance 18 which has the balance axis | shaft 25 in which the connection member 22 reciprocates up and down is demonstrated with reference to FIGS. As shown in FIG. 5, the sliding part manufacturing method includes a metal film forming process, a DLC film forming process (FIG. 5-1), a masking process (FIG. 5-2), and an etching process (FIG. 5-3). 3), the sliding portion 28 having a circular oil reservoir 32 for holding the lubricating oil on the surface is formed.

  As shown in FIG. 5A, in the metal film forming process and the DLC film forming process, a Cr film 29 is formed on the surface of the sliding portion 28 of the base material 27 made of a columnar steel material by about 0.5 μm, Further, a DLC film 30 of about 1.5 μm is formed on the surface of the Cr film 29. The Cr coating 29 and the DLC coating 30 are continuously formed by UBM sputtering in a vacuum. Specifically, first, sputtering is performed using Cr as a target, and after the Cr coating 29 has been formed to a predetermined thickness, next, while sputtering of Cr is performed, sputtering using graphite as a target is performed simultaneously. The DLC coating 30 is formed on the surface of the Cr coating 29 by shifting the sputtering rate of graphite and graphite so that the sputtering rate of graphite gradually increases.

  The hardness of the DLC film 30 can be adjusted by the hydrogen content or the like, and can be a high-hardness film having a high hardness of about 8000, which is close to HV of diamond, from several hundreds of HV. Further, the coefficient of friction of the DLC film 30 is about 0.1 or less. Therefore, the DLC film 30 is a film that is very excellent in wear resistance and slidability.

  As shown in FIGS. 5-2 and 6, in the masking process, the masking member 34 is fitted onto the surface of the DLC film 30 in a substantially close contact state, and a part of the surface of the DLC film 30 is masked. The masking member 34 is made of aluminum and has a cylindrical shape whose inner diameter is substantially the same as the outer shape of the DLC coating 30. The masking member 34 includes a plurality of circular holes 35 (through holes) having the same shape and arranged in a straight line in the vertical direction at regular intervals. The masking member 34 has 90 ° intervals in the circumferential direction and constant intervals in the vertical direction. They are offset. Therefore, even if the masking member 34 is fitted on the DLC film 30, only a part of the surface of the DLC film 30 is masked, and the position corresponding to the hole 35 of the masking member 34 remains exposed.

  As shown in FIG. 5-3, in the etching process, the masked balance 18 is introduced into a vacuum chamber, oxygen is introduced into the vacuum chamber, and a high frequency (eg, 13.8 MHz) high voltage is applied. The oxygen gas is applied and ionized to create a plasma atmosphere, and the DLC film 30 reacts with the oxygen plasma gas to become carbon dioxide or carbon monoxide, so that the exposed portion that is not masked by the masking member 34 Only the DLC film 30 is subjected to plasma etching until the Cr film 29 is exposed, and a plurality of recesses 31 that are oil reservoirs 32 are formed in the region of the sliding part 28.

  In this etching step, the balance 18 that has been quenched and tempered at about 250 ° C. is etched while being kept at 150 ° C. or lower, so that the balance 18 can be prevented from being deformed. Thereafter, the balance 18 is taken out from the vacuum chamber, and as shown in FIGS. 3 and 4, the balance shaft 25 having the sliding portion 28 in which the masking member 34 is removed from the balance shaft 25 and the oil reservoir 32 is formed. Complete.

  The manufacturing method of the balance 18 demonstrated above and the effect of the balance 18 are demonstrated. In this method of manufacturing the balance 18, the portion of the DLC film 30 that is not masked by the masking member 34 is removed by plasma etching to form the oil reservoir 32. Therefore, the oil reservoir 32 can be easily formed compared to machining. Can be formed. The oil reservoir 32 can be formed into a desired shape by making the masking member 34 into a desired shape. Although the DLC film 30 is etched by plasma etching, the Cr film 29 does not react with oxygen, and therefore remains, and the base material 27 made of a steel material is not covered with the Cr film 29 so that the base material 27 is rusted. It can be protected from deterioration due to.

  In the balance shaft 25 in which the oil reservoir 32 is formed, when the lubricating oil is supplied, a part of the lubricating oil is accumulated in the oil reservoir 32, so that the lubricating oil can be prevented from flowing out immediately. The oil supply cycle can be extended, and the baking life of the balance shaft 25 by supplying lubricant once can be extended. In particular, as shown in FIG. 7, the surface area ratio of the DLC film 30 that remains without being removed by plasma etching is 30% to 86% (that is, the recess 31 is 14% to 70% with respect to the surface area of the sliding portion 28). ), The baking life of the balance shaft 25 becomes 3000 hours or more, the supply cycle of the lubricating oil becomes very long, and the worker's supply operation of the lubricating oil can be greatly reduced.

  In the oil reservoir 32, since the circular concave portions 31 are arranged based on a predetermined pattern, it is possible to prevent the supplied lubricating oil from being biased and held in a part of the sliding portion 28, and to slide. Partial baking of the portion 28 can be prevented.

  A modified example in which the above-described embodiment is partially modified will be described.

  1) In the above-described embodiments, the DLC film 30 is formed by UBM sputtering. However, the DLC film may be formed by a physical vapor deposition method other than UBM sputtering, a chemical vapor deposition method such as a CVD method, or the like. .

  2) In the above-described embodiment, the masking member 34 is made of Al. However, the material constituting the masking member is not particularly limited as long as it is a material that hardly rusts, such as ceramic or stainless steel.

  3) In the above-described embodiment, the Cr coating 29 is formed between the base material 27 and the DLC coating 30, but the Cr coating 29 is not necessarily required and may be omitted. However, in this case, it is desirable to form a recess by etching the DLC film to such an extent that the base material is not exposed in the etching step, and to protect the base material from rusting by the DLC film. The DLC film may be etched until is exposed.

  4) In the above-described embodiment, the DLC film 30 is plasma etched until the Cr film 29 is exposed. However, a recess that does not expose the Cr film may be formed in the DLC film, and the recess may be used as an oil reservoir.

  6) In the above-described embodiment, the DLC film is removed by plasma etching in the etching process, but the DLC film may be removed by laser etching. For example, a femtosecond laser (laser wavelength is 870 nm, pulse width is femtosecond), an ultraviolet laser (laser wavelength is in the ultraviolet region. For example, a THG-YAG laser having a pulse width of 20 to 100 nm and a wavelength of 353 nm, The DLC film may be removed by a laser such as a solid laser such as an FHG-YAG laser having a wavelength of 265 nm) or an excimer laser (wavelength is 308 nm or 248 nm, pulse width is 20 to 30 nm). In particular, the etching process can be significantly shortened by irradiating the DLC film with a plurality of lasers from a plurality of directions to form oil reservoirs. Alternatively, by providing one laser and moving the relative position between the laser and the sliding component to form an oil reservoir, capital investment can be reduced.

  7) Instead of the Cr coating 29 described above, a W coating, a Ti coating, a Si coating, a Ni coating, or the like may be applied.

  8) In the above-described embodiment, the concave portion 31 is formed in a circular shape, but is not limited to a circular shape, and may be formed in a rectangular shape, a linear shape, a triangular shape, or the like. Further, although the oil reservoirs 32 are periodically formed at regular intervals, they may be formed at appropriate intervals.

  9) In the above-described embodiment, the present invention is applied to the balance shaft 25 of the sewing machine. However, the sliding part having a sliding part, for example, the needle bar 16, the needle bar support member 17, the connecting member 22 or the like, or the sewing machine The present invention can be applied to other sliding parts.

  10) In the above-described embodiments, the process from the metal film forming process to the etching process is continuously performed, but may be performed separately in time or region. For example, the metal film process and the DLC film formation process may be performed in country A, the part on which the DLC film is formed may be sent to country B, and the masking process and the etching process may be performed in country B.

  Note that the present invention is not limited to the above-described embodiment, and those skilled in the art can implement various modifications to the above-described embodiment without departing from the spirit of the present invention. In addition, the present invention includes such modified forms.

1 is an internal perspective view of a two-needle sewing machine according to an embodiment of the present invention. It is an internal left view for demonstrating a balance mechanism. It is a fragmentary perspective view of a sliding part. It is a partial fragmentary sectional view of the outline of a sliding part. It is process drawing explaining the manufacturing method of a sliding component. It is a figure explaining a masking process. It is a graph explaining the relationship between a DLC residual area and a burn-in lifetime.

M 2-needle sewing machine 18 Balance 27 Base material 28 Sliding part 29 Cr coating 30 DLC coating 31 Recessed part 32 Oil reservoir 34 Masking member

Claims (12)

In a manufacturing method of a sliding part having a sliding part on at least a part of the surface of the substrate, and forming a DLC film on the surface of the sliding part,
The sliding component is a component that is attached to a sewing machine configured with the sliding portion as a reciprocating sliding portion,
Wherein a masking member which masks a part of the surface of the DLC film and an inner diameter that can fitted on the sliding portion, straight in the sliding direction of the through hole of the multiple isomorphous at regular intervals A masking step in which the cylindrical masking members arranged in the outer surface of the DLC film are detachably fitted in a substantially close contact state;
An etching step of etching the portion of the DLC film that is not masked by the masking member;
Removing the masking member from the sliding part after the etching step;
A method for manufacturing a sliding part, comprising:   The method for manufacturing a sliding component according to claim 1, wherein in the etching step, a recess is formed by etching in a region of the sliding portion.   The method for manufacturing a sliding component according to claim 1, wherein a recess as an oil reservoir is formed in the etching step.   The method for manufacturing a sliding component according to claim 2 or 3, wherein, in the etching step, the concave portion is formed in an area ratio of 14% to 70% with respect to a surface area of the sliding portion. Before the step of forming the DLC film on the surface of the sliding portion,
The method for manufacturing a sliding component according to any one of claims 1 to 4, further comprising a metal film forming step of forming a metal film on a surface of the base material.   6. The method for manufacturing a sliding part according to claim 5, wherein in the etching step, the DLC film is etched until the metal film appears on the surface.   In the said masking process, each area | region where the surface of the said DLC film is exposed is circular, The manufacturing method of the sliding components as described in any one of Claims 1-6 characterized by the above-mentioned.   The said etching process removes the said DLC film by plasma etching, The manufacturing method of the sliding components as described in any one of Claims 1-7 characterized by the above-mentioned.   The method for manufacturing a sliding component according to claim 8, wherein the base material is made of a steel material, and the plasma etching is performed at a temperature of 150 ° C or lower.   The said etching process removes the said DLC film by laser etching, The manufacturing method of the sliding components as described in any one of Claims 1-7 characterized by the above-mentioned.   The sliding component manufactured by the manufacturing method as described in any one of Claims 1-10. The sliding component according to claim 11, wherein the sliding component is a balance having a scale shaft of a sewing machine.

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