JP2003225817A - Throwaway type drill - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve drill rigidity by providing favorable chip discharging performance. <P>SOLUTION: Recesses 26 formed are formed at centers of cutting edges 24 and 25, and inner side cutting edge parts 24a and 25a and outer side cutting edge parts 24b and 25b are provided on both sides of each recess 26. During the rotation of a drill body, a rotation locus of the inner side cutting edge part 25a of the cutting edge 25 overlaps with a rotation locus between the inner side cutting edge 24a and the outer side cutting edge 24b of the cutting edge 24, and a rotation locus of the outer side cutting edge part 24b of the cutting edge 24 overlaps with a rotation locus between the inner side cutting edge 25a and an outer side cutting edge 25b of the cutting edge 25. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a throw-away type drill (hereinafter referred to as a drill), and more specifically,
The present invention relates to a drill to which a throw-away tip (hereinafter, referred to as a tip) that constitutes a cutting edge of a drill is detachably attached to a tip of a drill body.

[0002]

2. Description of the Related Art In this type of drill, a pair of chip discharge grooves are formed on the tip of a substantially cylindrical drill body that is rotated around an axis line on opposite sides of the axis line. It is known that two chips having the same shape and the same size are detachably attached to a pair of chip attachment seats formed at the tip of the wall surface facing the drill rotation direction. Further, in such a drill, the tip mounting seat formed at the tip of one of the pair of chip discharging grooves is formed in the radial direction inner peripheral side of the drill body with respect to the axis, that is, near the axis. Then, the cutting edge of the tip attached to this tip mounting seat is also arranged so as to be biased toward the inner peripheral side, and the tip mounting seat at the tip of the other chip discharge groove is formed biased toward the outer peripheral side to cut the tip. The blade is also arranged on the outer peripheral side in a biased manner, and these cutting blades intersect and intersect with each other in the rotation trajectory around the axis, so that the inner peripheral side of the machining hole is cut by the inner peripheral side cutting blade. It is known that the outer peripheral side of the machined hole is machined by the outer peripheral side chip and the width of the chip produced by each cutting blade is set to about half the radius of the machined hole to improve the dischargeability. .

[0003]

However, even with a drill constructed in this way, the outer diameter D of the cutting edge, like the one used to form a machined hole with a small inner diameter and a deep hole depth, That is, chips are discharged in a drill in which the ratio L / D of the length L of the tip of the drill body in the axial direction to the diameter of a circle formed around the axis by the outer peripheral edge of the cutting edge of the tip on the outer peripheral side is as large as 5 or more. There was a risk of loss of sex. However, in such a case, the chip discharge groove may be formed deep and wide to increase the cross-sectional area thereof to improve the chip discharge property.
When the cross-sectional area of the chip discharge groove is increased in this way in a drill with a large / D, the core thickness of the drill body becomes smaller, and the drill rigidity is impaired, causing violent chatter vibrations, which causes a large noise during drilling. It may cause damage to the surrounding environment or break the drill body, and of course, the runout of the drill body during drilling and this runout causes the cutting edge to cut at a predetermined point when biting into a workpiece, for example. There is also a risk that processing accuracy will be deteriorated by not sticking to the position of.

On the other hand, in such a drill and a tip attached to the drill, for example, Japanese Patent Laid-Open No. 9-
150304 and Japanese Patent Laid-Open No. 9-290310.
Alternatively, in Japanese Patent Laid-Open No. 10-71516, etc., in a chip in which a cutting edge is formed on the upper side edge of a polygonal plate, a pair of corners R are provided at the corners of the polygon.
A tip in which a protruding portion having a portion is formed, and a drill in which such a tip is arranged on the outer peripheral side of the tip of the drill body have been proposed. However, in such a tip or drill, the chips generated by the cutting blade of the tip arranged on the outer peripheral side are divided by the corner R portion on the inner peripheral side of the protruding portion of the cutting blade, As a result, the chips are generated by being divided into three pieces, and it is possible to secure the chip discharging property, but the chips generated by the cutting blade of the tip arranged on the inner peripheral side are divided. Since it is not discharged, it is not possible to reduce the cross-sectional area of the chip discharge groove that is connected to the tip on the inner peripheral side, and therefore the core thickness of the drill body cannot be increased, ensuring sufficient drill rigidity. Is still difficult.

The present invention has been made under such a background, and even if the L / D is 5 or more, it is possible to improve the rigidity of the drill by exhibiting a good chip discharging property. Intended to provide a drill.

[0006]

In order to achieve the above object, the present invention proposes the following means. In the invention according to claim 1, each is detachably attached to an asymmetrical position sandwiching the axis of the drill body at the tip of the drill body, and one is located near the axis of the drill body and the other is the outer periphery of the drill body. In a throw-away type drill having two throw-away tips located on the side, each of the two throw-away tips having a cutting edge protruding from the tip of the drill body, the cutting edges of the throw-away tips are separated from each other on both sides. , And each has an inner cutting edge arranged inside the drill body and an outer cutting edge arranged outside thereof, and when the drill body rotates, the inner cutting edge and the outer cutting edge of the cutting edge of one of the throw-away tips. The rotation path of the inner cutting edge of the other throw-away tip overlaps with the rotation path between the blade and the other throw-away tip. Wherein the rotation locus of the outer cutting edge of the cutting edge of one of the throw-away tip overlaps on a rotating locus between the inner cutting edge and the outer cutting edge of the cutting edge in Ichippu.

According to the throw-away type drill of the present invention, since the cutting edge protruding from the tip of the drill body in the throw-away tip has the inner cutting edge portion and the outer cutting edge portion, the drill main body makes one revolution around the axis. During this, a total of four chips will be generated.

According to a second aspect of the present invention, in the throw-away drill according to the first aspect, the inner cutting edge portion and the outer cutting edge portion of the cutting edge have a recess at the center of the cutting edge of each throw-away tip. It is provided and formed.

According to the throw-away type drill of the present invention, since the inner cutting edge and the outer cutting edge of each cutting edge are formed by providing the concave portions, two cutting edge portions are provided on both cutting edges. It can be easily formed.

According to a third aspect of the present invention, in the throw-away drill according to the second aspect, the concave portion is formed by cutting out in a circular arc shape in a central portion of each of the cutting blades.

According to the throw-away type drill of the present invention, it is possible to prevent the connecting portion between the inner cutting edge and the outer cutting edge of each cutting edge from being sharpened by forming the arcuate recess. This is extremely advantageous in preventing damage to the chip. However, as in the invention according to claims 4 to 6, in the throw-away drill according to claim 2, the recess is formed by notching in a V shape, a trapezoidal shape, or a square shape in the central portion of each cutting edge. However, in this case, the chip can be easily formed.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings. 1 to 4 show a throw-away type drill (hereinafter,
FIG. 1 is a plan view of the drill, FIG. 2 is a side view of the drill, FIG. 3 is a front view of the drill, and FIG. 4 is an enlarged view of the tip of the drill. In the drill 10 of this embodiment, the drill body 11 has a substantially multi-stepped columnar shape with the axis O as the center, and while being rotated in the drill rotation direction T around the axis O, the tip side of the axis O direction ( The workpiece is perforated by being sent out toward the left side in FIGS. 1 and 2.

The rear end portion of the drill body 11 is a shank portion 12, and the tip end side of the shank portion 12 is a collar portion 13 having a larger diameter, and further than the collar portion 13. The tip side is a cutting blade body 14 that is inserted into a drilled hole during drilling.

The tip of the cutting blade 14, that is, the outer circumference from the tip of the drill body 11 to the collar 13 is opposite to each other with the axis O interposed therebetween, and the direction of drill rotation is toward the rear end. A pair of chip discharge grooves 15 and 15 having a twisted shape are formed on the rear side of T, and the wall surfaces 15A and 15 of the chip discharge grooves 15 and 15 facing the drill rotation direction T.
The throw-away tips 21 and 22 are detachably attached to the tip attachment seats 16 and 17 formed at the tip of A by the clamp screws 18, respectively.

These throw-away tips (hereinafter simply referred to as tips) 21 and 22 have the same shape and size as each other in the drill 10 of the present embodiment, and the tip bodies thereof are made of hard metal such as cemented carbide. The material is in the form of a substantially square flat plate, and the upper surface of the substantially square is the rake face 23, and the cutting edges 24, 25 are formed on one side of the square formed by the rake face 23. .

As shown in FIG. 4, recesses 26 are formed in the center of the cutting blades 24, 25 so as to be recessed inward, and the inner cutting blade portions 24a, 25a and the outer cutting blade portions are provided on both sides of the recess portion 26, respectively. 24b and 25b are provided. Therefore, the cutting edge 2
4 and 25 are inner cutting edges 24a, 25a which are separated from each other.
And outer cutting edges 24b and 25b. Recess 26
Has an arc shape in which the central portions of the cutting blades 24 and 25 are cut inward with an appropriate curvature.

In this embodiment, both chips 21,
In the same manner, the cutting edge 24, 25 and the recessed portion 26 are also provided on one side portion opposite to the one side portion having the cutting edge 24, 25 and are formed in the same manner.

Further, the peripheral surface of the chip body which intersects the rake face 23 via the cutting edges 24, 25 is a flank face, and the chips 21, 22 of this embodiment have the flank faces separated from the rake face 23 side. The lower surface on the side opposite to the rake surface 23 is a seating surface to be seated on the bottom surfaces of the chip mounting seats 16 and 17 (not shown). Further, an insertion hole through which the clamp screw 18 is inserted is provided at the center of the rake face 23.

Of the two chip mounting seats 16 and 17 for mounting the chips 21 and 22 thus constructed, one of the chip mounting seats 16 is arranged so as to be biased toward the inner peripheral side of the drill main body 11 and the other. The tip mounting seats 17 are unevenly arranged on the outer peripheral side of the drill body 11. These chips 2
As shown in FIG. 3, both 1 and 22 are along a center line B orthogonal to the axis O.

Then, the chips 21, 22 are mounted on the rake face 23 with respect to the chip mounting seats 16, 17 in the drill rotation direction T.
It is arranged so as to face to the side, and one of the chips 21 is
While positioning the cutting edges 24, 25 near the axis O,
The cutting blades 24 and 25 project to the inner peripheral side of the tip of the drill body 11, and the other tip 22 positions the cutting blades 24 and 25 on the outer peripheral side of the tip of the drill body 11 and
4, 25 are attached to the drill body 11 so as to project to the outer peripheral side of the tip.

The cutting edge 24 of the tip 21 and the cutting edge 25 of the tip 22 thus attached obtain a double rotation locus with each other when the drill body 11 rotates. The rotation loci of the cutting blades 25 intersect each other. That is, when the drill body 11 rotates, the inner cutting edge portion 25a of the cutting edge 25 overlaps with the inner cutting edge portion 25a of the cutting edge 24 while the inner cutting edge portion 25a of the cutting edge 24 overlaps between the inner cutting edge portion 24a and the outer cutting edge portion 24b. The outer cutting edge portion 24b of the cutting edge 24 overlaps with the outer cutting edge portion 25b of 25a.

That is, when the drill body 11 rotates, the inner cutting edge portion 2 of the cutting edge 25 of the tip 22 is located on the rotation locus between the inner cutting edge 24a and the outer cutting edge 24b of the cutting edge 24 of the tip 21.
The rotation loci of 5a overlap and the inner cutting edge 2 of the cutting edge 25
The rotation locus of the outer cutting edge portion 24b of the cutting edge 24 overlaps the rotation locus between the outer cutting edge 25b and the outer cutting edge 5b.

The outer cutting edge portion 24b of the cutting edge 24 and the inner cutting edge portion 25a of the cutting edge 25 are mounted so as to project to the most distal end side of the drill body 11, and the projecting amount is the axis line. The same amount is projected in the O direction. Also,
In the tip 21, the inner cutting edge portion 24a is arranged so as to be slightly overcenter beyond the axis O of the drill body 11, while in the tip 22, the outer cutting edge portion 25b is located behind the drill body 11. It is arranged so as to gradually extend toward the inner peripheral side as it goes. Further, the tip mounting seats 16 and 17 have cutting edges 24 of the tips 21 and 22,
Recesses each having a size such that it can be housed including the other three sides except one having 25 are formed.

As described above, in the drill 10 having the above-described structure, the tips 21 and 22 are attached to the tip of the drill main body 11 so as to be biased toward the inner and outer circumferences, and the cutting edges 24 protruding from the tip of the drill main body 11 at the tips 21 and 22. , 25 are provided with recesses 26, and inner cutting edge portions 24a, 25a and outer cutting edge portions 24b, 25b are provided, so that these inner cutting edge portions 24a, 25a and outer cutting edge portions 24b, 25b are ,
Since each drill body 11 is responsible for its own cutting region while having an overlapping region, a total of four chips are produced while the drill body 11 makes one revolution around the axis O. Therefore, the chip discharge grooves 15, 1
Even if the cross-sectional area of 5 is reduced to improve the drill rigidity, it is possible to prevent chip clogging and ensure good chip discharge performance, and chatter vibration due to insufficient rigidity, breakage of the drill body 11, or machining accuracy. It is possible to prevent a situation in which deterioration occurs, and smooth and stable drilling can be performed even if the L / D is 5 or more.

The inner cutting edge 24 of each cutting edge 24, 25
a, 25a and the outer cutting edge 24b, 25b between the recess 2
Since 6 is provided, two cutting edge portions 24a, 25a, which are arranged inward and outward, are provided on both cutting edges 24, 25.
24b and 25b can be easily formed.

Further, the concave portion 26 provided in the central portion of the cutting blades 24, 25 is formed in an arc shape, but for example, as shown in FIG. 5, the width becomes gradually narrower toward the inner side of the concave portion 26. Character shape or trapezoidal shape as shown in FIG. 6, or cutting edge 24,
It may be a rectangular shape as shown in FIG. 7 that opens in a “U” shape on the 25 side, and in these cases, the formation of the chips 21 and 22 is different from the case where the concave portion 26 has an arc shape. Can be easy. However, since the chips 21 and 22 are made of a hard material such as cemented carbide and have a brittle characteristic, the chips 21 and 22 are formed in a V shape or the like so that the inner cutting edges 24a and 25a and the outer cutting edge 24b on both sides thereof are formed. Since there is a risk of damage if the shape of the connecting portion with the connecting portions 25b and 25b is sharpened, it is possible to prevent the connecting portion from having a sharp shape by forming the arcuate recess 26 as described above. You can
This is extremely advantageous in preventing damage to the chip.

Further, the cutting edges 24, 25 of the chips 21, 22
If the inner cutting edges 24a, 25a and the outer cutting edges 24b, 25b are provided in the chip, the chips can be divided into four chips without increasing the cross-sectional area of the chip discharge groove.

Furthermore, since the cutting edges 24 and 25 are provided on the other side opposite to the one side having the cutting edges 24 and 25, when the cutting edges 24 and 25 on the one side are worn, the other edge is removed. It can be used by replacing the cutting edges 24, 25 of the parts with the tips. At that time, since the chips 21 and 22 are formed in a substantially square shape, even if the cutting blades 24 and 25 are replaced, the cutting blades 24 and 25 can be accurately positioned,
The cutting blades 24, 25 can be easily replaced.

[0029]

As described above, according to the invention of claim 1, in the throw-away tip, the cutting edge protruding from the tip of the drill body has the inner cutting edge portion and the outer cutting edge portion, which is high. The rigidity can be maintained, and a total of four chips are generated while the drill body makes one revolution around the axis, so that the chip discharge property can be improved.

According to the invention of claim 2, since the inner cutting edge and the outer cutting edge of each cutting edge are formed by providing the concave portions, two cutting edge portions can be easily provided on both of the cutting edges. Can be formed.

According to the third aspect of the present invention, by forming the arcuate recess, it is possible to prevent the connecting portion between the inner cutting edge and the outer cutting edge of each cutting edge from having a sharp shape. ,
This is extremely advantageous in preventing damage to the chip. On the other hand, claim 4
According to the inventions of to 6, by forming the concave portion in a V shape, a trapezoidal shape, and a rectangular shape, it is possible to easily form the chip.

[Brief description of drawings]

FIG. 1 is a plan view showing an embodiment of a throw-away drill of the present invention.

FIG. 2 is a side view of the throw-away drill.

FIG. 3 is also a front view of the throw-away drill.

FIG. 4 is an enlarged view showing a throw-away tip attached to a throw-away drill.

FIG. 5 is a plan view showing a modification of the throw-away tips 21 and 22 in which the recess 26 has a V shape.

FIG. 6 is a plan view showing a modification of the throw-away tips 21 and 22 in which the recess 26 has a trapezoidal shape.

FIG. 7 is a plan view showing a modified example of the throw-away tips 21 and 22 in which the recess 26 has a rectangular shape.

[Explanation of symbols]

10 Throw-away drill 11 drill body 14 cutting edge 15 Chip discharge groove 16,17 Chip mounting seat 21,22 throw-away tip 24,25 cutting edge 24a, 25a Inner cutting edge 24b, 25b Outer cutting edge 26 recess O Drill body axis T Drill body rotation direction

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Yasuhiko Kawade             1528, Nakashinden, Yokoi, Kobe-cho, Anpachi-gun, Gifu Prefecture             Address Mitsubishi Materials Corporation Gifu Factory             Within F-term (reference) 3C037 BB00

Claims (6)

[Claims] 1. Each of the drill bodies is detachably attached to an asymmetrical position sandwiching the axis of the drill body at the tip of the drill body, and one is located near the axis of the drill body and the other is located on the outer peripheral side of the drill body. In a throw-away type drill having two throw-away tips, each of the two throw-away tips having a cutting edge protruding from the tip of the drill body, the cutting edges of each of the throw-away tips are spaced from each other on both sides, and the drill Each has an inner cutting edge arranged inside the main body and an outer cutting edge arranged outside thereof, and when the drill main body rotates, the inner cutting edge and the outer cutting edge of the cutting edge of one of the throwaway tips On the rotation trajectory between
While the rotation trajectories of the inner cutting edge of the cutting edge of the other throw-away tip overlap, the one throw-away tip is on the rotation trajectory between the inner cutting edge and the outer cutting edge of the cutting edge of the other throw-away tip. A throw-away type drill characterized in that the rotational trajectories of the outer cutting edge of the cutting edge in are overlapped. 2. The throw-away type drill according to claim 1, wherein the inner cutting edge portion and the outer cutting edge portion of the cutting edge are formed by providing a concave portion at a central portion of a cutting edge of each throw-away tip. A throw-away type drill characterized by. 3. The throw-away drill according to claim 2, wherein the concave portion is formed by cutting out in a circular arc shape in the central portion of each of the cutting blades. 4. The throw-away drill according to claim 2, wherein the recess is formed by notching in a V-shape at the center of each cutting edge. 5. The throw-away drill according to claim 2, wherein the recess is formed by notching in a trapezoidal shape in the central portion of each cutting edge. 6. The throw-away drill according to claim 2, wherein the recess is formed by notching in a rectangular shape in the central portion of each of the cutting blades.