JP4166238B2 - Opening tool for soft material - Google Patents

Description

  The present invention relates to an opening device that can open a beautiful round hole in a soft material such as rubber.

  As shown in FIG. 10, a drill 100, which is a representative tool for opening a round hole, has an edge 101 formed in the radial direction (corresponding to a radius) of a drill tip to a workpiece (metal or wood) W. The workpiece W is squeezed while rotating to pierce and scrape the workpiece W from the surface side, and the chips (cutting chips) S generated as a fine tear shape or a coiled flow shape are drill grooves 102 on the outer peripheral surface. Along the shank to the shank side (the base side of the drill 100). In the drilling process using the drill 100, it is well known that when the drill 100 penetrates the workpiece W, a burr T is generated at the peripheral edge of the drilled side.

This burr T has the trouble of removing it from the back surface side of the workpiece W by post-processing (burr removal work) such as chamfering. Therefore, conventionally, a drill is provided with a recess on the rear side of the drill tip so that the burr T can be removed at the time of drilling, and a chamfering blade whose radial edge is directed in the recess is provided in the recess. Has been proposed (see, for example, Patent Document 1).
In the drill according to this proposal, after the drill penetrates the workpiece W, the drill is once moved slightly in the direction perpendicular to the axis (one eccentric direction) (swinged sideways) and slightly pulled back in the axial direction. A complicated chamfering process that combines an operation of pressing the chamfering blade against the peripheral edge of the hole and a returning operation such as subsequent axial extrusion and lateral swing return is necessary. That is, as a result, the process has not been reduced, and the conventional drilling machine cannot be used.

By the way, in order to perform drilling with the drill 100, the workpiece W needs to have a certain degree of hardness and cannot be drilled into a soft material (it is easy to understand if the soft material is considered to be a sponge or the like). That is, when the drill 100 is pressed against the soft material while rotating, the soft material easily undergoes elastic deformation, and the diametrical edge 101 at the tip of the drill does not cause any piercing or scooping action. This is because the contact force with respect to the surface becomes a high pressure, and a biting phenomenon occurs.
Therefore, when the rotary processing device has a low torque, the driving rotation may stop, and when the rotary processing device has a high torque, the drill 100 may be broken. Even if a hole can be drilled, the hole diameter may be smaller than the drill diameter, or the hole shape may be distorted instead of circular.

  Therefore, the present inventor has developed a hole opening tool 120 as shown in FIGS. This hole-opening tool 120 is suitable for punching a hole for air venting in a hollow soft material such as a shock-absorbing rubber tube of an automobile door, and is held by a tool mounting part (chuck part, etc.) of a rotary processing apparatus. It has a shank portion (not shown) to be made and a blade portion 121 provided at the tip of the shank portion, and the blade portion 121 is the center of the tip (diameter direction) of a tool material (round bar) having a circular cross section. In addition, a V-notch-shaped slit (cut) 122 is formed by polishing or the like, and it is bifurcated so that a bowl-shaped blade 123 protrudes on both sides thereof. Each blade 123 has a cylindrical back surface 123a that remains in a state where the outer peripheral surface of the shank portion is extended as it is, and the tip of the blade 123 has a sharp blade edge 123b. A region that is applied to both side edges 123c of the body 123 is used as a cutting blade.

That is, when the punch 120 is rotated and pressed against the soft material N such as the shock-absorbing rubber tube, a cutting blade (blade edge 123b to side edge 123c) is formed on the surface of the soft material N. It is in a state of cutting into the thickness of the soft material N while generating a cutting action that draws a line along the outline of the round hole to be attempted. In other words, this is a cutting mechanism similar to a razor or a cutter blade. According to the opening tool 120, it is possible to open a beautiful circular hole in the soft material N.
In the punching process using the punch 120, a disk-shaped or columnar chip-shaped cutting rod G formed by cutting the outer periphery with a cutting blade (blade edge 123b to side edge 123c) is gradually formed. It is compressed by the opening tool 120 inside the round hole, and when the opening tool 120 penetrates the soft material N, it is discharged together to the penetration destination. This chip-shaped cutting rod G is completely different from the so-called burr T. In this way, in view of the cutting mechanism and the occurrence situation of the chip-shaped cutting rod G, it is clear that the hole opening tool 120 is completely different from the technical idea of the hole drilling by the drill 100.
Japanese Patent Laid-Open No. 4-152009

In the opening tool 120 developed by the present inventor, as shown by a two-dot chain line in FIG. 12, the opening tool 120 penetrates the soft material N and is discharged together to the penetration point. In some cases, cocoon G did not peel off from the soft material N and remained. Therefore, after the drilling process is completed, the operator must check the presence or absence of the chip-shaped cutting rod G and tear the chip-shaped cutting rod G if it is found. Further, if the chip-shaped cutting rod G is overlooked in the inspection, an appearance defect may be caused.
Further, since the perforated counterpart is the soft material N, and the chip-shaped cutting rod G is naturally the same soft material N, as shown in FIG. Small convex pieces Y may occur, but in some cases (depending on the product manufactured by the soft material N or the manufacturer of the product), these dents X and convex pieces Y are judged to be a factor that lowers the product value. Sometimes there was.

  In addition, the punching process to such a soft material N may be performed with respect to a hollow tube material. For example, it is a sealing tube attached around the door of an automobile, and the round hole is for inserting an attachment rod on the automobile side. In this case, the round hole only penetrates a part of the peripheral wall of the tube material, and cannot penetrate the tube material itself, so that the chip-shaped cutting rod G is generated inside the tube. Moreover, there are many round holes at fine pitches along the longitudinal direction of the tube material. For this reason, it is very troublesome and difficult to check and tear the chip-like cutting chips G.

In addition, when fine drilling or powdering of the soft material N is generated during the drilling process, and the pitch is changed by heat change, they adhere to the periphery of the blade part 121 (such as each blade 123) of the punching tool 120, and thereafter As a result, the sharpness of the hole-opening tool 120 is shortened, and the life of the hole-opening tool 120 is shortened.
The present invention has been made in view of the above circumstances, and in a soft material punch for punching a soft material such as rubber, it is possible to open a beautiful circular hole, An object of the present invention is to provide a soft material punch that prevents the chip-like cut residue from remaining on the periphery and prolongs the service life.

In order to achieve the above object, the present invention has taken the following measures.
That is, the blade present invention, to form a shank portion, a support neck formed on the positive polygonal shape small diameter that Batch, a round hole into a soft material with provided through the support neck ahead of the shank portion And
The blade section, by forming a V-notch-shaped slit reaching pre Symbol support neck, a pair of blades only arranged in opposing form across the slit,
Wherein each blade body has, on the cylindrical rear drawn by the radial distance of the round holes, a cutting blade the blade edge faces the other party of the blade portion, and a burr blade cutting edge facing the front Symbol support neck Formed ,
When the outer edge of the support neck is formed with an electric discharge machining wire while changing the angle by the number of regular polygonal sides of the support neck, the edge of the burr blade is connected to the support neck (3 ) From the base side to the blade portion, and is pulled out obliquely rearward at the portion where the burrow blade is formed, so that the edge of the blade edge and the edge of the blade edge formed in a semicircular direction toward the support neck A cutting edge formed on both sides with sharp teeth .

In the case of an opening tool having such a configuration, a round blade to be formed can be formed by a cutting blade in the blade portion in the same manner as the opening tool developed by the present applicant (see FIGS. 11 and 12). With a cutting action that draws a line along the hole outline (a cutting mechanism similar to that of a razor or a cutter blade), it is possible to open a beautiful circular hole in a soft material.
Not only that, after the punch has penetrated through the soft material, even if the chip-shaped cutting chips discharged together to the tip of the punch remain without being peeled off from the soft material, When pulling out from the cutting edge, the edge of the round hole and the chip-shaped cutting edge are cut off by the pulling-like cutting action (similar cutting mechanism as a razor or cutter blade). It is.

Therefore, after the opening tool is actually pulled out from the soft material, the chip-shaped cutting residue does not remain on the soft material. Naturally, after the drilling process is completed, the troublesome work of checking the presence or absence of the chip-like cutting flaws and tearing off the chip-like cutting flaws becomes unnecessary. In addition, since there are no small dents or protrusions caused by the tearing of the chip-shaped cutting rod, it is possible to prevent the value of the product manufactured from the soft material from being lowered.
It is preferable that the blade portion is provided with a pair of blades that are arranged to face each other with a slit. If it does in this way, a cutting effect | action can be increased by the number of blades, it becomes suitable for improving the sharpness and reducing the strength burden of each blade, and improving the durability as a blade part. Further, the formation of the blade portion is rather easy as compared with the case where the blade is provided in a single piece.

The burrs of the blade portion may have a plurality of blade edges in the circumferential direction, and a recessed blade bottom may be formed between adjacent blade edges. By doing in this way, the area | region which can be cut | disconnected will increase as a result, and it will lead to improving sharpness.
It is preferable that the cutting blade and the burring blade of the blade portion have surface roughness and hardness obtained by wire electric discharge machining in oil. In other words, the surface roughness obtained by wire electric discharge machining in oil is moderately rough compared to the surface roughness obtained by polishing, which leads to a reduction in cutting resistance (contact surface pressure) against soft materials. This is useful for improving sharpness. It is also useful for improving the peelability of the pitch. The hardness obtained by wire electric discharge machining in oil is moderately hard compared to the hardness obtained by polishing, and the durability is increased accordingly.

  The soft material opening tool according to the present invention can open a beautiful circular hole in a soft material such as rubber. In addition, the chip-shaped cutting residue does not remain on the periphery of the formed round hole. Moreover, it has become possible to extend the service life as a hole punch.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
1 to 7 show a first embodiment of a soft material punch 1 according to the present invention. The soft material N is a rubber sealing tube attached around the door of an automobile. The opening tool 1 has a shank portion 2 and a blade portion 4 provided at the tip of the shank portion 2 via a support neck portion 3 and is integrally formed. For example, a cemented carbide is used as the forming material.
The shank portion 2 is to be held by a tool mounting portion (chuck portion or the like) 6 of the rotary processing device 5 and has various cross-sectional shapes (half-moon shape, square shape, or It is a rod-shaped portion formed as another polygon. What is necessary is just to select suitably the length, thickness, etc. of this shank part 2 according to the outer diameter of the blade part 4. FIG.

The blade part 4 has a pair (two) of blades 10 facing each other with the rotation axis of the shank part 2 sandwiched between them. A split (break) 11 is provided. As shown in FIG. 1, each blade 10 has an axial length L that is equal to or greater than the thickness t of the soft material N, and a round hole 12 that is to be opened around the rotational axis of the shank portion 2. Are formed with a cylindrical back surface 13 drawn with a radial distance Φ / 2 and side edges 14 on both sides that give a width H (see FIG. 3 and the like) to be finite in the circumferential direction.
In addition, in this blade part 4, although the site | part (radius position of the round hole 12) used as the largest outer diameter from the rotating shaft center of the shank part 2 is the columnar back surface 13 as mentioned above, The support neck 3 is formed with a narrower diameter than the columnar back surface 13 of the blade portion 4. Further, the V-notch-shaped slit 11 provided between the opposed blades 10 reaches the support neck 3.

Each blade 10 is provided with a cutting blade 20 and a burr blade 21. The cutting blade 20 has a blade edge 22 facing forward. A region extending from the blade edge 22 to the side edges 14 on both sides is formed in a toe-shaped arc shape in which an ellipse is divided in half by a short axis, and this arc-shaped region is cut as the cutting blade 20. It is an area.
The cutting blade 20 formed in this way exists on the same plane as the cylindrical back surface 13. That is, when the punching tool 1 is rotated and pressed against the surface of the soft material N, the cutting blade 20 comes into contact with the soft material N at right angles to the surface thereof, and is a round that is intended to open the hole. It will be in the state contact | abutted by the surface pair with respect to the hole 12 inner peripheral surface. For this reason, the cutting blade 20 has a cutting action (cutting mechanism similar to that of a razor or a cutter blade) that draws along the hole contour of the round hole 12, and the soft material N has a beautiful circular hole. 12 can be opened.

The burrs 21 have a plurality of cutting edges (three in total in the illustrated example, the central cutting edges 24 and the cutting edges 25 on both sides thereof) directed toward the support neck 3. A portion between the adjacent portions 25 is formed in a recessed shape, and a blade bottom 26 is formed by the recessed portion. A region extending from the central blade edge 24 to the blade bottoms 26 on both sides thereof is formed in a semicircular shape. Further, the blade edges 25 on both sides are formed in a tooth-like shape in a region between the side edge 14 and the blade bottom 26. The semicircular region formed by the central blade edge 24 and the fang region formed by the blade edges 25 on both sides are cutting regions as the burrs 21.
The burrs 21 formed in this way also exist on the same plane as the cylindrical back surface 13. That is, by forming the round hole 12 in the soft material N with the aperture 1, the blade portion 4 penetrates the soft material N, and then the aperture 1 is coaxially pulled back in the round hole 12. The burrs 21 are in a positional relationship perpendicular to the back surface with respect to the soft material N, and are in a state where the round holes 12 come into contact with the inner peripheral surface of the holes by face-to-face contact.

For this reason, the burring blade 21 has a cutting action (cutting mechanism similar to that of a razor or a cutter blade) that draws along the hole contour of the round hole 12, and the chip-shaped cutting rod G remains in the round hole 12. If this happens, it can be cut off reliably.
The support neck 3 described above has a regular polygonal cross-sectional shape (in the first embodiment, a regular hexagon) around the rotation axis of the shank portion 2. Then, both end positions (corner ridge lines) of one side of the regular polygon are positioned so as to coincide with the blade bottom 26 provided on the edge blade 21 of the blade portion 4. This is because wire electric discharge machining is adopted when forming the burrs 21.

  In the wire electrical discharge machining, a voltage is applied between the tool material forming the aperture tool 1 and a wire made of ultrafine (for example, about 0.25 mm) brass or the like, and is discharged in oil (or in ionic water). This is a method of cutting the tool material by destroying the metal molecules of the tool material. The wire is bitten so as to form each outer surface of the support neck 3 from the base side of the support neck 3 (near the shank 2) toward the blade 4 and is obliquely formed from the tool material at the portion where the burr blade 21 is formed. Pull out backwards and repeat this while changing the angle by the number of sides of the regular polygonal shape of the support neck 3, so that the above-mentioned shape (with the blade edges 24, 25 and the blade bottom 26) is a blade. 21 will be formed.

The cutting edge 20 and the burring blade 21 formed by employing wire electric discharge machining in oil have a surface roughness that is moderately rough compared to the surface roughness obtained by polishing. Accordingly, the cutting resistance (contact surface pressure) with the soft material N is reduced accordingly, so that the sharpness can be improved and the peelability of the pitch can be improved. Also, regarding the hardness, the wire electric discharge machining in oil is moderately harder than the hardness obtained by polishing, so that the durability as the opening tool 1 is increased accordingly.
As shown in FIG. 5, the outer diameter Φ of the blade portion 4 (same as the hole diameter of the round hole 12 provided in the soft material N) can correspond to about 1 to 10 mm, and the axial length L of the blade 10 Can correspond to about 1-2 mm. Further, the opening angle θ of the V-notch-shaped slot 11 provided between the blades 10 can be set to about 20 to 50 ° (preferably around 30 °). In this case, if it is smaller than 20 °, the soft material N is generated. If a pitch or the like adheres to the slit 11, it may be difficult to remove it, and if it is larger than 50 °, the sharpness of the cutting blade 20 may be reduced. The angle α of the burrow blade 21 with respect to the support neck 3 can be about 20 to 60 ° (preferably around 30 °). In this case, if the angle is less than 20 °, the strength of the burrow blade 21 is reduced. There is a possibility that the sharpness of the blade 21 may be reduced.

If it is the aperture tool 1 which comprises the structure explained in full detail above, as shown in FIG. 7, with the cutting blade 20 in the blade part 4, the aperture tool (refer FIG.11 and FIG.12) which the present applicant developed in earnest Similarly, a cutting action (cutting mechanism similar to that of a razor or a cutter blade) is generated along the hole contour of the round hole 12, and a clean circular hole 12 is formed in the soft material N. Can do.
Not only that, after the punch 1 has penetrated the soft material N, the chip-shaped cutting rod G discharged together to the penetration destination remains without being peeled off from the soft material N. When the hole tool 1 is pulled out from the soft material N, the portion where the opening edge of the round hole 12 and the chip-shaped cutting rod G are connected by the burring blade 21 in the blade portion 4 is a streak-like cutting action (razor or cutter). It is cut off reliably by the same cutting mechanism as the blade).

Therefore, after the punch 1 is actually pulled out from the soft material N, the chip-shaped cutting rod G does not remain. Naturally, after the drilling process is completed, the troublesome work of checking the presence or absence of the chip-shaped cutting rod G or tearing off the chip-shaped cutting rod G becomes unnecessary. Moreover, since the small dent X and the convex piece Y (refer FIG. 13) resulting from the tearing of the chip-shaped cutting stick G do not arise, it can also prevent that the value of the goods manufactured with the soft material N falls.
In addition, the opening tool 1 of 1st Embodiment has the cutting edge in the cutting edge 20 provided in each blade 10, and the cutting edge 21 from the cutting edge 22 and 25 to the side edge 14 of both sides, respectively. Since it is provided, the direction of rotation is not limited. That is, since it can be used in forward rotation or reverse rotation, there is an advantage that a usable site is not selected (general versatility is increased).

FIG. 8 shows a second embodiment of the punch 1 according to the present invention. The most different point from the punch 1 of the first embodiment is the axial length of the blade 10 in the blade portion 4. Is that the support neck 3 has a square cross section. Other configurations and operational effects are substantially the same as those of the first embodiment, and a detailed description thereof is omitted here.
FIG. 9 shows a second embodiment of the aperture 1 according to the present invention. In this aperture 1, a diamond reinforcement at the center in the width direction with respect to the blade 10 of the blade 4. The point 30 is provided. Such a reinforcing portion 30 is obtained by embedding a diamond tip at a predetermined position in a mold for molding the round bar at the stage of manufacturing a carbide round bar as a forming material of the aperture 1. Then, wire electric discharge machining for forming the support neck 3 and the blade 4 may be performed.

By the way, the present invention is not limited to the above embodiments, and can be appropriately changed according to the embodiments.
For example, only one blade 10 can be used. The cutting blade 20 and the burring blade 21 may be provided with a cutting edge only in a region extending from the cutting edge 22 or 25 to one of the side edges 14 (the side edge 14 that precedes when rotating). it can.
The support neck portion 3 can have a cross-sectional shape having a desired number of square shapes from square to regular decagon.

  The soft material N that can be perforated by the perforating tool 1 may be rubber, resin, paper or fabric.

It is the side view which showed the use condition about 1st Embodiment of the opening tool which concerns on this invention. It is the middle abbreviation perspective view showing the opening tool of a 1st embodiment. It is an AA arrow directional view of FIG. It is a BB line arrow directional view of FIG. It is CC sectional view taken on the line of FIG. FIG. 6 is a view taken along line DD in FIG. 4. It is the side view explaining the opening mechanism about the opening tool of 1st Embodiment. It is the side view which showed 2nd Embodiment of the opening tool which concerns on this invention with the same viewing angle as FIG. It is the side view which showed 3rd Embodiment of the opening tool which concerns on this invention with the same viewing angle as FIG. It is the side view explaining the drilling mechanism of the drill generally used for drilling. It is the perspective view which showed the front-end | tip part of the hole opening tool for soft materials which the present applicant developed extensively. It is the side view explaining the opening mechanism by the opening tool of FIG. FIG. 12 is a partial plan view of the soft material illustrating a phenomenon that is sometimes a difficulty when the soft material is punched by the opening tool of FIG. 11.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Opening tool 2 Shank part 3 Support neck part 4 Blade part 5 Rotation processing device 6 Tool attachment part 10 Blade body 12 Round hole 13 Columnar back surface 14 Side edge 20 Cutting blade 21 Cut edge 22 Cutting edge 24 Edge Center edge 25 Edge edge on both sides of the edge 26 Edge of the edge 26 N soft material

Claims (1)

Shank portion (2), a supporting neck portion formed in the positive polygonal shape small diameter that Batch (3), soft material with disposed through the tip to the support neck (3) of the shank portion (2) ( N) with a blade (4) for forming a round hole (12),
The cutting unit (4), by pre-forming Symbol support neck (3) V notch-shaped slit reaching the (11), a pair of blades arranged in opposed form across the slit (11) With body (10)
Each blade (10) has a cutting edge (20) with a blade edge (22) facing the tip of the blade portion (4) on a cylindrical back surface (13) drawn by the radial distance of the round hole (12). ) and it is cutting edge before Symbol support neck (3) and burrs blade (21) pointing towards the formation,
When the outer edge of the support neck (3) is formed with the wire for electric discharge machining while changing the angle of the edge of the burr blade (21) by the number of regular polygonal sides of the support neck (3). The wire is bitten from the base side of the support neck portion (3) toward the blade portion (4), and is pulled out obliquely rearward at the portion where the burr blade (21) is formed, whereby the support neck portion (3 And a cutting edge (24) formed in a semicircular shape facing toward the edge) and a cutting edge (25) formed so as to be pointed like a tooth on both sides of the cutting edge (24). Opening tool for materials.

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