JP2007057008A - Method for manufacturing cross-sectionally deformed wire-rod pierced with through-hole - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for manufacturing a cross-sectionally deformed wire-rod in which adhesion of sputtered matters are reduced, referring to a method for manufacturing a cross-sectionally deformed wire-rod having a small cross section. <P>SOLUTION: The manufacturing method is referred to a cross-sectionally deformed wire-rod to be used e.g. to an oil-ring in which a plurality of through holes are pierced longitudinally, and the circumscribed circle of the cross section is at most 10 mm. The manufacturing method comprises at least an oiling process for applying oil on the surface of the cross-sectionally deformed wire-rod wherein the through holes are pierced, a preliminary hole-piercing process for piercing holes respectively in a smaller size than a specified size by a laser beam, and a finished-hole-piercing process for piercing holes respectively by the laser beam in the specified size. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a method for producing a cross-section deformed wire having a plurality of through holes in the longitudinal direction of the wire.

  A drilling method using a laser has been proposed as a method of forming a through-hole in the manufacture of a deformed wire having a plurality of through-holes of a predetermined size used in a two-piece type oil ring or the like in the longitudinal direction of the wire.

For example, Patent Document 1 proposes an improvement in the characteristic that a shape failure such as cracks and burrs in the steel oil ring does not occur by forming a through hole communicating with the radial direction of the steel oil ring by laser beam processing. ing.
In patent document 1, it consists of two, the case where a hole is formed in the state of a wire before ring forming, and the case where a hole is formed after ring forming. In any case, since no punching is used, the ring is free from cracks and burrs.
Patent Document 2 discloses that heating is performed using a high thermal energy density heating method including a YAG laser, and oxygen or air is used as an assist gas. Another feature is that the solidified residue (dross) generated at the time of drilling the through hole is reheated and melted and blown off from the emission side. Although specific numerical values such as dimensions of the wire thick part, hole width and hole length, and assist gas pressure are described, no description is given for countermeasures against sputtering. For dross countermeasures, the effectiveness of the in-line dross removal method by rubbing (grinding, cutting, chipping) is described.
JP-A-3-260473 Japanese Patent Laid-Open No. 9-159025

Although the method for manufacturing a steel oil ring disclosed in Patent Document 1 or 2 described above is advantageous in terms of reducing the man-hours for drilling, the metal (hereinafter referred to as sputter) that has been melted and removed by laser processing on the surface of the cross-section deformed wire rod. ) Was scattered and adhered.
Unlike the dross generated at the boundary with the perforated part, this problem occurs at a distance from the perforated part and scattered at random positions. There was a problem that removal was extremely difficult. If spatter remains, it may interfere with the installation of the spring arranged inside the oil ring, and may cause contact with the local cylinder (local wear). In addition, there is a risk that spatter will fall off during use of the engine and metal lump will be mixed in the engine lubricating oil, causing damage to the cylinder wall.
The above-described spatter problem also occurs in linear guide rails and the like, which are applications of small cross-section shaped wires that require through-hole formation processing.

  In view of the above-described problems, an object of the present invention is to provide a method for manufacturing a cross-sectional deformed wire with reduced spatter adhesion in a method for manufacturing a cross-shaped deformed wire having a small cross section.

  The present inventor forms a pre-drilling step of drilling a hole having a size smaller than a predetermined size, and then forming a hole having a predetermined size, in a state where oil is applied to a surface on which a through-hole of the cross-section deformed wire having a small cross section is formed. It has been found that the use of the finish drilling process can greatly reduce the adhesion of spatter to the cross-section deformed wire, and the present invention has been achieved.

  That is, the present invention is a method for manufacturing a cross-section deformed wire having a plurality of through-holes in the longitudinal direction of the wire and having a cross-section circumscribed circle of 10 mm or less, and applying oil to at least the surface on which the cross-shaped deformed wire is formed. A method of manufacturing a cross-sectional deformed wire having a through hole having an oil application step, a preliminary drilling step of drilling a hole having a size smaller than a predetermined size by a laser, and a finishing drilling step of forming a hole of a predetermined size by a laser. is there.

  Preferably, the cross-sectionally deformed wire is a method for producing a cross-shaped deformed wire having a through hole which is a wire for an oil ring having a substantially H-shaped cross section.

  According to the present invention, it is possible to remarkably reduce the adhesion of spatter, so that it is indispensable for improving the quality and productivity of a deformed wire having a small cross section that requires a through hole forming process such as a two-piece type oil ring. It becomes an important technology that can not be.

An important feature of the present invention lies in the combination of oil application and a plurality of through-hole forming processes for the purpose of preventing spattering on a cross-section deformed wire having a small cross section in the laser drilling process.
Specifically, an oil application step is first provided for applying oil to at least the surface on which the through hole of the cross-sectionally shaped wire rod is formed.
Oil application has the effect of drastically reducing spatter. The effect is considered to be due to the prevention of the occurrence of welding by suppressing the direct contact between the metal surface and the droplet when the scattered metal droplet lands on the metal surface.
However, this method alone cannot completely suppress the sputter close to the through hole. This is thought to be due to the fact that the scattering distance is short and the cooling is difficult.

On the other hand, looking at the relationship between laser drilling treatment and sputtering, once the hole has penetrated, it has been generated on the surface until now, and it has been a driving source for spatter scattering. It was confirmed that the assist gas used escaped to the opposite side through the through hole, and the droplets scattered by laser processing were drastically reduced.
Therefore, in order to take advantage of the effect of limiting the generation of spatter to a portion close to the through hole by oil application, a preliminary drilling step for drilling a small diameter hole is first provided. Since the drilling process has a small diameter, it is not necessary to introduce high energy, which is also effective in suppressing sputtering.

Next, a finishing drilling step for forming holes of a predetermined size is provided. As a result, the holes formed in the pre-drilling step are expanded, so that the sputtered portion limited to the vicinity of the through-hole, that is, the substantial expanded portion is processed and removed by the effect of oil application.
And since the through-holes through which the gas escapes have already been formed, the above-described effects can further reduce the spatter in the finishing process, and in combination with the effect of oil application, almost no spatter can be generated. It was done.

  In the present invention, the circumscribed circle of the cross-section is limited to a cross-section deformed wire having a cross-section of 10 mm or less, in the processing of a wire having a size of 10 mm or more, it is not possible to maintain the superiority of processing productivity over general machining, This is because the size of the steel oil ring material generally does not exceed 10 mm.

Further, it is preferable to apply oil to the entire surface of the surface where the through hole is formed in order to prevent the spatter from adhering to the surface where the spatter is scattered.
Applying oil directly to the cross-section deformed wire with a brush or the like can provide a sufficient effect, but considering productivity, a method of injecting oil with a tube pump immediately before laser processing, or the inside of an oil tank It is also possible to take a method of adhering through immersion, or a method of attaching oil to absorbent cotton or the like and adhering it to the deformed wire rod.

  The type of oil is preferably mineral oil such as rolling oil, lubricating oil, rust preventive oil, etc., and vegetable oils and emulsions can also be used. Water is not preferable because rusting of the material is a concern. Liquid that replaces oil with too low viscosity is easily removed by high-pressure assist gas, which is useless. Further, if the amount of oil adhered, that is, the oil film thickness is 1 μm or more on one side of the perforated surface, the effect of preventing spatter adhesion can be clearly obtained. However, if the amount of oil film is small, the molten metal is not sufficiently cooled, and spatter is likely to adhere. On the other hand, if the amount of oil attached is too large, there will be problems in handling such as conveying materials, and most of the oil may be removed by assist gas, so the oil film thickness before laser processing is about 1 to 10 μm on one side Is preferred.

  By increasing the beam diameter of the next drilling process to be performed in accordance with the preliminary drilling diameter, the amount of spatter scattering can be suppressed to a level that does not affect a hole having a predetermined dimension. For example, the preliminary drilling process can be penetrated with φ0.4 mm or less.

The oil ring material has a cross-sectional shape as shown in FIG. 1, and there is a hole in the central part of the cross-section of FIG. It plays the role of the content shown. FIG. 2 is a plan view showing the through-hole portion.
The oil ring reciprocates on the inner wall surface of the cylinder to form an appropriate amount of lubricating oil film on the inner wall surface of the cylinder. That is, when the piston approaches the combustion part, the lower rail part scrapes off the lubricating oil on the inner wall surface and discharges it from the through hole of the web part. Conversely, when the piston moves away from the combustion part, excess lubricant is scraped off by the upper and lower rail parts. Therefore, the part which connects two rail parts is required, and a cross-sectional shape takes H shape.

When the cross-section deformed wire rod of the present invention is applied to an oil ring, the shape is as shown in FIGS. At this time, the thickness 1 of the web part is 0.7 mm or less, the width 2 of the through hole formed in the web part is 0.1 to 1.2 mm, the length 3 of the through hole is 0.1 to 5.0 mm, and the through hole is formed. The pitch 4 of the holes is 1 to 10 mm and is extremely small.
The dimension 5 between the insides of the two rails is reduced to 2 mm or less in order to reduce the amount of lubricant scraped off. The dimension in the width direction of the through hole is also narrowed to 1.2 mm or less, and further to 0.4 mm or less.

Lasers that can be used in the present invention include CO ₂ laser, CO laser, dye laser, excimer laser, YAG laser, YVO 4 laser, titanium sapphire laser, ruby laser, glass laser, fiber laser, semiconductor laser, and dye laser. Preferably, by using a YAG laser, the wavelength is as short as 1 μm, the heat absorption rate of the workpiece is high, and a high output can be obtained. Moreover, it is easy to automate the equipment, and the processing speed can be further increased.
Further, with respect to the assist gas, it is effective in improving the hole quality and stable machining to further increase the flow velocity and to create a state in which the flow is not disturbed.

  Recently, linear guide rails having a thickness of about 2 mm have been used in optical fiber connection devices. The guide rail portion is a deformed wire having the same cross section as the oil ring, and the material is also stainless steel or tool steel. A fixing method using screws is used to fix the linear guide rail. At the time of screw hole machining, the lower hole is drilled and threaded. By applying laser drilling to this drilling, the machining time can be shortened and the drilling tool can be omitted, contributing to the rationalization of the linear guide rail.

  The workpiece has the dimensions shown in FIG. 1, and the material used is a rolled material equivalent to SUS440B and SUS420J2 specified in JIS G4303. The oil was applied by brushing on the perforated surface of the cross-sectionally deformed wire. As the oil, cold rolling oil (viscosity 20 cSt / 40 ° C.) was used. As processing conditions, a YAG pulse laser with an output of 6 kW was used as the laser used. The sizes of the holes drilled in the cross-section deformed wire were through-hole widths 0.2, 0.4, and 0.6 mm, through-hole length 0.6 mm, through-hole pitch 10 mm, and web thickness 0.55 mm. The preliminary drilling beam diameters were φ0.2 mm and φ0.3 mm, and the final drilling beam diameters were φ0.4 mm and φ0.6 mm. Pre-drilling and finish drilling were carried out in separate passes. The feeding speed of the wire was 6 m / min. The assist gas was nitrogen gas, compressed air, and oxygen gas. The assist gas nozzle diameter was 0.17 mm, and the distance (standoff amount) between the tip of the assist gas nozzle and the workpiece was 0.3 mm. The quality of the through hole was observed off-line using a stereomicroscope. Under the conditions shown in Table 1, spatter adhesion was confirmed in laser drilling. The spatter adherence was observed over the full length and the full width with a 40-fold stereo microscope, the adhering matter having a diameter of 2 μm or more was counted, and the average number of spatter adherents per perforated hole was determined.

  In the embodiment of the present invention, the drill hole is drilled by preliminary drilling in a state where the rolling oil is applied to the perforated surface of the cross-section deformed wire, and then the total length and the full width of the cross-section deformed wire are subjected to spatter adhesion. The final drilling beam diameter was not confirmed. On the other hand, the total length and the full width of the cross-section deformed wire, in which the pre-drilling process is not performed in the state where the rolling oil is applied to the perforated surface of the cross-section deformed wire, and only the finish perforation is performed, per one perforated hole On average, adhesion of two spatters was confirmed. In particular, it was confirmed that the amount of spatter deposition increased as the diameter of the finished drilling beam increased. In addition, the total length and the full width of the cross-section deformed wire obtained by performing preliminary drilling and finishing drilling on a wire rod in which rolling oil is not applied to the perforated surface of the cross-section deformed wire which is a comparative example are per one perforated through hole. On the other hand, adhesion of 4 spatters was confirmed on average.

It is a block diagram which shows an example of this invention. It is a top view which shows the through-hole part of FIG.

Explanation of symbols

1. Web thickness, 2. 2. the width of the through hole; 3. the length of the through hole; 4. Pitch of through holes, Inner dimensions between rails, 6. Rail part, 7. Through hole

Claims (2)

A method of manufacturing a cross-section deformed wire having a plurality of through-holes in the longitudinal direction of the wire and having a cross-section circumscribed circle of 10 mm or less, and an oil application step of applying oil to at least a surface forming the through-hole of the cross-section deformed wire; A method for producing a cross-sectional deformed wire having a through hole, comprising: a preliminary drilling step of drilling a hole having a size smaller than a predetermined size by a laser; and a finish drilling step of forming a hole of a predetermined size by a laser. The method of manufacturing a cross-shaped deformed wire having a through hole according to claim 1, wherein the cross-shaped deformed wire is an oil ring wire having a substantially H-shaped cross section.

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