JP2008036759A - Drill - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve wear resistance of a cutting blade in a drill having the cutting blade with a different tip end angle depending on the position. <P>SOLUTION: The drill 21 is formed to be the shape where a point angle of the cutting blade 6 is reduced by the continuous change from the point angle A° (where 0°<A°<180°) at the central position to the tip angle 0° at the maximum diameter position from the central position toward the maximum diameter position (D-D), and a relief angle of the cutting blade 6 is reduced by the continuous change from the central position toward the maximum diameter position. The cutting blade 6 of the drill 21 composes the cutting blade for reaming by having the relief angle (ε) at the maximum diameter position. Since the cutting edge and a flank of the cutting blade 6 has no corner, the cutting blade has an excellent wear resistance. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a drill having a cutting edge whose tip angle varies depending on the position.

As a drill having a cutting edge whose tip angle varies depending on the position, there are double angle drills described in Patent Documents 1 and 2.
This double angle drill is composed of a primary cutting edge whose tip is the tip of a metal drill, and a flat secondary cutting edge that is continuous with the primary cutting edge and has a tip angle smaller than the primary cutting edge. .
According to this document, this double angle drill is suitable for simultaneous drilling of a composite material of fiber reinforced resin and metal.
According to this double angle drill, a primary hole having a relatively small diameter is first drilled by the primary cutting edge, and then the secondary cutting edge cuts the outer periphery of the primary hole to drill a secondary hole having a target diameter. At the time of drilling, transient delamination (delamination) occurs around the primary hole of the composite material, and this delamination is removed when cutting with the secondary cutting edge.
JP-A 63-306812 Japanese Utility Model Publication No. 6-75612

However, as described in Patent Document 2, the double-angle drill originally has a defect that the wear resistance is not excellent. In the invention described in Patent Document 2, the wear resistance is improved by coating the cutting edge with a diamond film having an appropriate thickness.
However, in double-angle drills, there are corners at the boundary between the primary cutting edge and the secondary cutting edge and at the outermost periphery of the secondary cutting edge. These corners tend to concentrate stress and easily cause chipping. It is a geometric cause that reduces wear.

Further, in the double angle drill, there are still the following problems in drilling the component material in which the metal material and the fiber reinforced resin composite material are combined.
When drilling the above components from the metal side with a double-angle drill, the primary cutting edge cannot completely cut the fibers in the fiber-reinforced resin composite part when drilling the fiber-reinforced resin composite part after drilling the metal part. It penetrates and spreads and is cut with a secondary cutting edge. At this time, delamination and fiber fraying spread within the constituent material at the site that has been spread. The delamination and fiber fray spreading inside the component may remain without being cut and cut even by the secondary cutting blade.
Conversely, when drilling the above components from the fiber reinforced resin composite material side with a double angle drill, even when drilling the metal material part after drilling the fiber reinforced resin composite material part, use a secondary cutting blade with a rake angle. Since the fiber reinforced resin composite material is scooped up and cut, burrs and fiber fraying may occur at the perforated portion entrance.

  This invention is made | formed in view of the problem in the above prior art, Comprising: It aims at improving the abrasion resistance of a cutting blade in the drill which has a cutting blade from which a tip angle differs according to a position. This enables high-precision drilling over a long period of time.

  Another object of the present invention is to prevent delamination and fiber fraying from occurring in a fiber reinforced resin composite material even when perforating a metal material and a fiber reinforced resin composite material.

  The invention according to claim 1 for solving the above-described problems is that the tip angle of the cutting edge is from the center position tip angle A ° (where 0 ° <A ° <180 °) from the center position toward the maximum diameter position. The drill is formed in a shape that decreases with a continuous change to the maximum diameter position tip angle of 0 °, and the clearance angle of the cutting blade decreases with a continuous change from the center position toward the maximum diameter position.

  The invention according to claim 2 is the drill according to claim 1, characterized in that it has a clearance angle (ε) at the maximum diameter position.

  The invention according to claim 3 is the drill according to claim 1 or 2, characterized in that the tip of the cutting blade is formed in a parabolic shape consisting of a part of a parabola.

  The invention according to claim 4 is the drill according to claim 1 or 2, wherein the tip of the cutting edge is formed in an arc shape by one arc.

  The invention according to claim 5 is characterized by having a center position tip angle A and a center position clearance angle δ satisfying a relationship of δ> (180−A) / 2, where δ is a clearance angle at the center position. It is a drill as described in any one of Claims 1-4.

  A sixth aspect of the present invention is the drill according to any one of the first to fifth aspects, wherein the cutting edge has a rake angle.

  The invention according to claim 7 is the drill according to any one of claims 1 to 5, wherein a rake angle of the cutting edge is zero.

  The invention according to claim 8 has two twist grooves, and has a margin at both edges along the twist groove of the land portion formed between the twist grooves. It is a drill as described in any one of Claim 7.

  The invention according to claim 9 is characterized in that the length along the center axis of the cutting edge is 1.6 times or more of the maximum diameter. It is a drill as described in any one.

According to the present invention, since the tip angle of the cutting edge decreases due to a continuous change from the center position to the maximum diameter position, an angle that tends to be lost does not occur at the cutting edge, and the wear resistance of the cutting edge is improved.
In addition, according to the present invention, the clearance angle of the cutting edge is reduced by a continuous change, so that a corner that easily wears is not generated on the clearance surface, and the wear resistance of the cutting edge is improved.
In addition, according to the present invention, the cutting edge tip forms a curved line (including a case where the straight line is included in part), so that the cutting edge of the same size is compared to the conventional cutting edge in which the cutting edge tip is configured by a straight line. Compared with each other, the blade length becomes longer. By increasing the blade length, the cutting amount per unit length of the cutting edge tip is reduced with respect to a fixed cutting amount, and therefore the wear amount is also reduced, so that the wear resistance of the cutting blade is improved.
According to the present invention, the wear resistance of the cutting blade is improved as described above, thereby enabling highly accurate drilling over a long period of time.

  According to the second aspect of the present invention, the reaming cutting edge portion is formed by having the clearance angle (ε) at the maximum diameter position, and reaming with the cutting edge becomes possible. Such a reaming cutting blade portion is continuous with a drilling cutting blade portion on the distal end side. The cutting edge is integrated from the cutting edge for drilling to the cutting edge for reaming, and the tip angle and clearance angle of the cutting edge are continuously changing. A corner that is easily worn out does not occur on the surface, and even if such a reaming cutting edge is provided, the wear resistance of the cutting edge is not deteriorated.

  Hereinafter, an embodiment of the present invention will be described with reference to the drawings. The following is one embodiment of the present invention and does not limit the present invention.

[First Embodiment]
First, a first embodiment of the present invention will be described with reference to FIGS. FIG. 1 is a side view showing a drill according to a first embodiment of the present invention.
As shown in FIG. 1, the drill 21 of the present embodiment has only a blade portion 1 and a shank portion 2. A twist groove 3 is formed between the blade 1 and the shank 2.

FIG. 2 shows an enlarged view of the tip of the drill 21 shown in FIG.
A pair of cutting blades 6 and 6 are provided symmetrically with respect to the central axis 9 in the blade 1. The cutting edges 6 and 6 each have a rake face 7 and a flank face 8.
Only the blade portion 1 is cross-sinned, and a rake face 7 is formed at a portion missing by the thinning. Further, the portion missing due to the thinning continues to the twisted groove 3. The two twisted grooves 3 and 3 are twisted with a certain twist angle. Margins 5 and 5 are formed at both edges along the twisted grooves 3 and 3 of the land portion 4 formed between the twisted grooves 3 and 3. The margin 5 is a portion that hits the inner surface of the hole to be processed and supports the drill and burnishing.

  As shown in FIG. 2, the blade 1 has a maximum diameter φD1 and a length L1. The tip angle of the cutting edge 6 at the center position is A ° (however, 0 ° <A ° <180 °). The center position tip angle A is suitably in the range of 90 ° <A ° <150 °. The tip angle of the cutting edge 6 is 0 ° at the position having the maximum diameter φD1 (DD position).

  The tip angle of the cutting edge 6 is formed in a shape that decreases with a continuous change from the center position tip angle A ° to the maximum diameter position tip angle 0 °. Thereby, the tip of the cutting edge 6 forms a smooth curve without corners (discontinuous points). The curve formed by the tip of the cutting edge 6 is a curve that swells outward without an inflection point. For example, the tip of the cutting edge 6 forms a curve from the center position tip angle A ° to the maximum diameter position tip angle 0 ° as a part of the parabola. A part of the tip of the cutting edge 6 may include a straight line. However, even when the straight line and the curve (not including the straight line) are changed, the tip angle of the cutting edge 6 is continuously changed so that no corner is provided.

  FIG. 3 is a side view of the drill 21 as seen from the direction of the arrow F shown in FIG. The drill 21 has a symmetrical three-dimensional shape with the axis 9 as the center. Therefore, the side surface seen from any angle of the drill 21 has the same shape as the side surface on the opposite side of 180 degrees.

  4A1 is a cross-sectional view taken along line BB shown in FIG. FIG. 4A2 is a cross-sectional view taken along the line CC shown in FIG. FIG. 4A3 is a cross-sectional view taken along the line DD shown in FIG. FIG. 4A4 is a cross-sectional view taken along line EE shown in FIG. FIG. 4 (b1) is a detailed view of part B1 shown in FIG. 4 (a1). FIG. 4 (b2) is a detailed view of the portion C1 shown in FIG. 4 (a2). FIG. 4 (b3) is a detailed view of the portion D1 shown in FIG. 4 (a3). FIG. 4 (b4) is a detailed view of the E1 portion shown in FIG. 4 (a4).

As shown in FIG. 3, the clearance angle at the center position is δ °. It is preferable that the center position tip angle A and the center position clearance angle δ satisfy the relationship δ> (180−A) / 2. FIG. 3 shows the case where δ = 45 °.
As shown in FIGS. 4 (b1), (b2), and (b3), the clearance angle of the cutting edge 6 gradually decreases due to a continuous change from the center position clearance angle δ as it moves backward from the tip along the central axis 9. It decreases to the clearance angle ε in the DD line. FIG. 3 and FIG. 4 show the case where δ = 45 °, the position of the clearance angle 30 ° is shown by the line BB, the position of the clearance angle 20 ° is shown by the line CC, and the case where ε = 5 ° is shown. Yes. Thus, the drill 21 is formed in a shape in which the clearance angle of the cutting edge 6 is reduced by a continuous change from the center position toward the maximum diameter position (DD line). The condition is ε <δ. A range of ε <15 ° is appropriate.

Further, as shown in FIG. 4 (a4), margins 5 and 5 are formed at both edges along the twisted grooves 3 and 3 of the land portion 4 formed between the twisted grooves 3 and 3, respectively. A total of four margins 5 are formed along the outer periphery. In the land portion 4, a relief portion 4 a that is recessed between the margins 5 and 5 is formed. For example, the width of the margin 5 is 0.1 to 1.5 mm, the width of the escape portion 4a is 2.5 mm, and the depth of the escape portion 4 is 0.3 to 1.2 mm.
Further, as shown in FIGS. 4 (a1) to (a3) and (b1) to (b3), the cutting edge 6 is not provided with a rake angle. That is, the rake angle is zero and the rake face 7 is perpendicular to the work surface.

  The drill 21 having the above configuration is suitable for processing a fiber reinforced resin composite material such as CFRP because the cutting edge 6 is not provided with a rake angle. This is because the fiber-reinforced resin composite material is more accurately processed by cutting than the shearing process, and a clean processed surface free from fiber breakage or the like can be obtained. That is, it is less likely that delamination (delamination) occurs and the cutting can be performed with high precision and accuracy when cutting by cutting finely without providing a rake angle rather than cutting with a rake angle.

  When this drill 21 is applied to processing of a fiber reinforced resin composite material, it is preferable that the slenderness ratio (L1 / φD1) of the blade portion 1 is 1.6 or more. For example, (L1 / φD1) = 1.6. Thereby, it is possible to obtain a sufficient cutting edge length of a cutting edge having a relatively small tip angle corresponding to the secondary cutting edge of the double angle drill described above. Even if transient delamination occurs around the hole in the composite material drilled by the cutting edge having a relatively large tip angle on the drill tip side, this delamination has a relatively small tip angle. It is removed at the time of cutting by the cutting blade having.

  Further, according to the drill 21 of the present embodiment, the cutting blade 6 shown in FIGS. 4 (a3) and (b3) constitutes a reaming cutting blade having a tip angle of 0 ° and a clearance angle ε. Following drilling, reaming with this cutting edge is possible. Further, following the reamer finishing with the cutting edge, the burnishing finish processing with the margin 5 is performed, and the hole to be processed is precisely finished. From drilling to finishing can be performed with the drill 21.

  Further, the drill 21 of the present embodiment has four margins 5 along the torsion grooves. With these four margins, the drill 21 is supported at four points in any cross section, and the position of the four fulcrums moves according to the axial direction position by twisting. For this reason, it is possible to perform hole processing with less bending and being held stably on the inner surface of the hole to be processed or the bush guide.

  According to the drill 21 of the present embodiment, the tip angle and the relief angle of the cutting edge 6 are continuously changed, so that an angle that tends to be lost does not occur at the cutting edge, and an angle that tends to wear out does not occur on the flank. Wearability is good, and the above-described highly accurate drilling can be performed over a long period of time.

  Next, when drilling the component 30 shown in FIG. 5 with a drill 21a in which the tip end angle A of the center position of the drill 21 is 120 ° and the slenderness ratio (L1 / φD1) of the blade 1 is 1.6. explain. As shown in FIG. 5, the constituent material 30 is formed by combining a metal material 31 and a fiber reinforced resin composite material 32.

  FIGS. 5A to 5C show a case where the component 30 is drilled from the metal 31 side by the drill 21a. Since the tip of the cutting edge of the drill 21a is formed in a smooth curve, cutting proceeds smoothly from the metal material 31 to the fiber reinforced resin composite material 32. As shown in FIG. 5B, the fiber reinforced resin composite material 32 is cut by a cutting blade having a relatively large tip angle on the tip side of the drill. Even if transient delamination occurs around the perforated fiber reinforced resin composite 32, this delamination is removed during subsequent cutting with a cutting edge having a relatively small tip angle ( FIG. 5 (b) → (c)). Furthermore, as shown in FIG. 5 (c), the cutting edge having a tip angle of 0 ° and a clearance angle ε hits parallel to the work surface and cuts, so that no burr or the like occurs.

  FIGS. 5D to 5F show a case where the component 30 is drilled from the fiber reinforced resin composite 32 side by the drill 21a. Since the tip of the cutting edge of the drill 21 a is formed in a smooth curve, cutting proceeds smoothly from the fiber reinforced resin composite material 32 to the metal material 31. As shown in FIG. 5D, the fiber reinforced resin composite material 32 is cut by a cutting blade having a relatively large tip angle on the tip side of the drill. Even if transient delamination occurs around the hole in the perforated fiber reinforced resin composite material 32, this delamination is removed during subsequent cutting with a cutting edge having a relatively small tip angle. Further, since the cutting edge having a tip angle of 0 ° and a clearance angle ε hits the cutting surface of the fiber reinforced resin composite material 32 and the metal material 31 in parallel, the burrs are not generated.

  As shown in FIG. 6, in the case where the component material 30 is drilled from the metal material 31 side by the drill 21a and the component material 30 is drilled from the fiber reinforced resin composite material 32 side by the drill 21a, as shown in FIG. A clean and accurate hole 33 in which no burrs or the like are generated in the reinforced resin composite material 32 and the metal material 31 can be processed.

[Second Embodiment]
Next, a second embodiment of the present invention will be described. FIG. 7 is a sectional view showing a drill according to a second embodiment of the present invention. The positional relationship of the cross section is the same as in FIG. The drill 22 of the present embodiment is a drill suitable for metal processing having a cutting edge with a rake angle.
As shown in FIGS. 7 (a1) to (a3) and (b1) to (b3), the cutting edge 6a is provided with a rake angle. That is, the rake face 7a of the cutting edge 6a is inclined to the flank 8 side from the line 10 perpendicular to the work surface. Other shapes are the same as the drill 21 of the first embodiment. The dimensions of each part are designed according to the application.

  When this drill 22 is applied to metal processing, for example, as shown in FIG. 8, the slenderness ratio (L1 / φD1) of the blade portion 1 is made smaller than that for the composite material. In this case, the tip of the cutting edge 6 of the drill 22 can be formed in an arc shape by one arc having a curvature radius R as shown in FIG. If it forms in the shape of a circular arc by one circular arc, manufacture of a drill will become comparatively easy.

[Third Embodiment]
Next, a third embodiment of the present invention will be described. FIG. 9 is a side view showing a drill according to a third embodiment of the present invention. 10 is a cross-sectional view taken along the line GG shown in FIG. The drill 23 of the present embodiment is obtained by replacing the torsion groove 3 in the drill 21 of the first embodiment with a V groove 11.

  As shown in FIG. 9, the drill 23 has only the blade portion 1 b and the shank portion 2. A pair of cutting blades 6b, 6b are provided symmetrically with respect to the central axis 9 in the blade portion 1b. Each of the cutting edges 6b and 6b has a rake face 7b and a flank face 8b. As shown in FIGS. 9 and 10, two V grooves 11 and 11 are formed between the blade portion 1 b and the shank portion 2. The V-groove 11 is formed straight along the central axis 9 including a missing portion due to thinning of the blade portion 1b.

  As shown in FIG. 10, margins 13 and 13 are formed at both edges along the V grooves 11 and 11 of the land portion 12 formed between the V grooves 11 and 11. The margin 13 is a portion that hits the inner surface of the hole to be processed and supports the drill and burnishing. With these four margins, the drill 23 is supported at four points in any cross section. Although there is no support by twisting, it is stably held on the inner surface of the hole to be machined or the bush guide, and drilling with less bending is possible.

It is a side view which shows the drill of 1st Embodiment of this invention. It is an enlarged view of the front-end | tip part of the drill shown in FIG. It is the side view of a drill seen from the direction of arrow F shown in FIG. (a1) is sectional drawing in the BB line shown in FIG. (a2) is sectional drawing in the CC line. (a3) is sectional drawing in the DD line. (a4) is sectional drawing in the EE line. (b1) is a detailed view of B1 part shown in (a1). (b2) is a detailed view of the C1 part shown in (a2). (b3) is a detailed view of a D1 portion shown in (a3). (b4) is a detailed view of a portion E1 shown in (a4). It is a figure which shows the mode of the drilling by the drill of 1st Embodiment of this invention. It is sectional drawing which shows the hole drilled with the drill of 1st Embodiment of this invention. It is sectional drawing which shows the drill of 2nd Embodiment of this invention. It is a front-end | tip part side view which shows an example of the drill of 2nd Embodiment of this invention. It is a side view which shows the drill of 3rd Embodiment of this invention. It is sectional drawing in the GG line shown in FIG.

Explanation of symbols

1 Cutting edge 2 Shank 3 Torsion groove 4 Land 5 Margin 6 Cutting edge 7 Rake face 8 Flank 11 V groove 12 Land 13 Margin φD1 Maximum diameter

Claims (9)

  The cutting edge tip angle decreases from the center position toward the maximum diameter position by a continuous change from the center position tip angle A ° (however, 0 ° <A ° <180 °) to the maximum diameter position tip angle 0 °. A drill with a shape in which the clearance angle of the blade decreases with a continuous change from the center position toward the maximum diameter position.   The drill according to claim 1, wherein the drill has a clearance angle at the maximum diameter position.   The drill according to claim 1 or 2, wherein a tip of the cutting blade is formed in a parabolic shape including a part of a parabola.   The drill according to claim 1 or 2, wherein a tip of the cutting blade is formed in an arc shape by one arc.   5. The center position tip angle A and the center position clearance angle δ satisfying the relationship of δ> (180−A) / 2, where δ is a clearance angle at the center position. 6. The drill according to any one of them.   The said cutting blade has a rake angle, The drill as described in any one of Claims 1-5 characterized by the above-mentioned.   The drill according to any one of claims 1 to 5, wherein a rake angle of the cutting edge is zero.   8. The structure according to claim 1, comprising two twisted grooves, and a margin at both edges along the twisted groove of a land portion formed between the twisted grooves. Drill as described in.   The drill according to any one of claims 1 to 8, wherein a length along a center axis of the cutting edge is 1.6 times or more of the maximum diameter.

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