JP3022002B2 - Indexable inserts and indexable drilling tools - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a throw-away tip (hereinafter abbreviated as a tip) which is particularly suitable for a drilling tool, and a throw which is attached to the tip of a tool body to form a bottom blade. It relates to an away type drilling tool.

[0002]

2. Description of the Related Art As such a throw-away type drilling tool, for example, the one shown in FIG. 8 is known. This is disclosed in Japanese Utility Model Laid-Open Publication No. 62-201612, in which an inner peripheral cutting edge tip 2 and an outer peripheral cutting edge tip 3 are provided at the tip of a tool body 1 rotated around an axis O. It is configured to be mounted. These cutting blade tips 2,
Numeral 3 is a positive tip having a substantially equilateral triangle shape in plan view, having the same shape and size, and one surface forming the equilateral triangle is a rake face, and each side edge is a side edge cutting edge 4. At the top of the equilateral triangle, two nose cutting edges 5, 5 forming an angle larger than the apex angle are formed.
A nose round blade 6 is provided at the intersection between the two nose cutting blades 5 and 5, and a radius blade 7 between the cutting edges is provided at the intersection between the edge ridge cutting blade 4 and the nose cutting blade 5. Is formed.

[0003] Here, the inner peripheral side cutting edge tip 2 has one side of the nose radius blade 6 located at the apex of the top of one of the equilateral triangles formed by the rake face of the inner peripheral side cutting edge tip 2. The side edge cutting edge 4 connected to the side and the one nose edge cutting edge 5 adjacent to the one side edge cutting edge 4 and located on the inner peripheral side thereof are formed as bottom blades. One of the inter-cutting edge blades 7 at the intersection of the side edge cutting edge 4 and the nose portion cutting edge 5 is mounted on the tool main body 1 so as to protrude toward the tip side in the direction of the axis O. The inner peripheral cutting edge tip 2 is disposed such that the nose radius blade 6 located at the apex is over centered beyond the axis O. On the other hand, the outer peripheral side cutting edge tip 3 has, at the top of one of the equilateral triangles formed by the rake face, a side ridge cutting edge 4 connected to the other side with respect to the nose round blade 6 located at the vertex, and the other side. The other nose portion cutting edge 5 adjacent to the side edge portion cutting edge 4 and located on the outer peripheral side thereof is a bottom edge, and the intersection of the other side edge portion cutting edge 4 and the nose portion cutting edge 5 is provided. The other inter-cutting edge blade 7 of the portion is mounted on the tool body 1 so as to protrude toward the front end in the direction of the axis O. Further, the outer peripheral side cutting edge chip 3 is arranged such that the nose portion cutting edge 5 on one side adjacent to the other nose portion cutting edge 5 serving as the bottom blade via the nose radius blade 6 moves rearward in the axis O direction. The tool O is disposed so as to face the inner peripheral side of the tool body 1 with respect to the axis O.

[0004] The inner peripheral cutting edge tip 2 and the outer peripheral cutting edge tip 3 are, as shown in FIG. One imaginary straight line L perpendicular to the axis O is formed so that the cutting edges 4, 4 intersect at the intersection P, and the inter-cutting edge blades 7, 7 projecting toward the tip of the both cutting edge tips 2, 3 in the direction of the axis O. It is arranged to match above. Thus, in the throw-away type drilling tool having such a configuration, one cutting edge tip can be used three times as the inner peripheral side cutting edge 2 and three times as the outer peripheral side cutting edge tip 3. Thus, it is possible to use the cutting blade six times in total, and it is possible to obtain the advantage that the cutting blade formed on the chip can be used up evenly and the utilization efficiency of the cutting blade chip can be improved to the utmost.

[0005]

By the way, in the machining with such a drilling tool, the chip generated by the inner cutting edge tip 2 and the chip generated by the outer cutting edge tip 3 have different properties. Different chips are produced. That is, specifically, the length of the rotation trajectory of the bottom blade per one rotation of the tool body 1 is such that the radius of rotation on the radially outer side with respect to the axis O is larger than that on the radially inner side. Therefore, chips that are longer on the outer cutting edge tip 3 than on the inner cutting edge tip 2 are generated.

However, in the throw-away type drilling tool having the above-described configuration, the inner peripheral side cutting edge tip 2 and the outer peripheral side cutting edge tip 3 have the same shape and the same size. The one side edge cutting edge 4, the nose cutting edge 5, and a rake face connected to the inside of these chips;
The other side edge cutting edge 4 and the nose cutting edge 5, which are the bottom blades of the outer peripheral side cutting edge tip 3, and the rake face connected to the inside of these tips also have the same shape.
Therefore, it is difficult for a throw-away type drilling tool equipped with such a tip to cope with chips generated in different properties as described above. There has been a problem that long chips cause chip clogging and hinder smooth drilling. On the other hand, in order to solve such a problem, when the inner peripheral side cutting edge tip 2 and the outer peripheral side cutting edge tip 3 use chips of different shapes corresponding to the chips generated by each, The advantage that the utilization efficiency of one chip can be improved to the utmost is completely lost.

The present invention has been made in view of such circumstances, and has as its object the purpose of using a single tip as the inner peripheral side cutting edge tip or using it as the outer peripheral side cutting edge tip. Even in such a case, it is an object of the present invention to provide a chip that can cope with chips generated in different properties as described above, and a throw-away type drill that enables smooth drilling by using such a chip. To provide tools.

[0008]

According to a first aspect of the present invention, there is provided a chip in which a rake face is formed on at least one surface forming the polygon of a polygonal flat chip body. A side edge cutting edge is formed on a pair of side edges connected to at least one apex of the rake face, and the one apex is symmetrical with respect to a bisector of the apex and the apex angle of the apex. Form a pair of nose cutting edges that make a large angle,
In addition, a nose round blade is formed at the intersection of the pair of nose cutting blades, and a round blade between the cutting edges is formed at the intersection of the side ridge cutting blade and the nose cutting blade. One side edge cutting edge of the pair of side edge cutting edges and one nose edge cutting edge adjacent to the one side edge cutting edge have an inner surface on the rake face connected to the inside of the chip. While forming a peripheral chip breaker, the chip inward of the other side ridge cutting edge of the pair of side ridge cutting edges and the other nose portion cutting edge adjacent to the other side ridge cutting edge An outer peripheral chip breaker having a shape different from that of the inner peripheral chip breaker is formed on the rake face connected to the rake face. A chip according to a second aspect is the chip according to the first aspect, wherein the outer chip breaker is a chip breaker depressed from the rake face with respect to the inner chip breaker.

Further, the indexable drilling tool according to a third aspect of the present invention includes an inner peripheral side cutting edge tip forming a central portion of a bottom edge at a tip end of a tool body rotated around an axis.
In a throw-away type drilling tool in which an outer peripheral side cutting tip forming an outer peripheral portion of a bottom blade is detachably attached, the inner peripheral side cutting edge and the outer peripheral side cutting tip have the same shape and the same size. Using the chip of claim 1 or claim 2,
In the inner peripheral side cutting edge tip, the one side edge cutting edge and the one nose portion cutting edge are used as the bottom edge, and the one nose portion cutting edge is on the inner peripheral side of the one side edge cutting edge. Position it,
The one cutting edge between the cutting edges located at the intersection of the one side edge cutting edge and the one nose cutting edge protrudes toward the axial end side, and is adjacent to the one nose cutting edge. The nose radius blade is disposed so as to be over center beyond the axis, and in the outer peripheral side cutting edge tip, the other side edge cutting edge and the other nose portion cutting edge are bottom blades,
This other nose cutting edge is located on the outer peripheral side of the other side ridge cutting edge, and the other cutting edge located at the intersection of the other side ridge cutting edge and the other nose cutting edge A tool in which the one rounded nose cutting edge is protruded toward the axial front end side and the one nose cutting edge adjacent to the other nose cutting edge via the nose round blade is directed toward the axially proximal end side. Disposed so as to face the inner peripheral side of the main body, furthermore, these outer peripheral side cutting edge tip and the inner peripheral side cutting edge tip, with one of the side ridge cutting edges along a rotation locus on a plane including the axis. The other side ridge cutting edge intersects with each other, and the one inter-cutting edge round blade and the other cutting edge round edge are disposed so as to coincide with one virtual straight line perpendicular to the axis. It is characterized by the following.

[0010]

According to the indexable drilling tool having such a configuration, the insert according to claim 1 or 2 having the same shape and size as the inner peripheral side cutting edge tip and the outer peripheral side cutting edge tip is used. Therefore, one chip can be used rationally and its high use efficiency can be maintained.

In the chip having the above-mentioned structure, when the tip is used as the inner peripheral side cutting edge, the one side edge cutting edge and one nose portion cutting edge are used as the bottom edge, and the outer peripheral side cutting edge is used. When used as a blade tip, the other side edge part cutting edge and the other nose part cutting edge will be used as the bottom edge, but these one side edge part cutting edge and the nose part cutting edge, and the other An inner chip breaker and an outer chip breaker having mutually different shapes are formed on the rake faces of the side ridge portion cutting edge and the nose portion cutting edge which are connected to the inside of the chip. Therefore, according to the throw-away type drilling tool equipped with such a chip, the inner peripheral chip breaker and the outer peripheral chip breaker are formed into shapes corresponding to the chips generated by the cutting blades on each side. By doing so, it becomes possible to prevent the occurrence of chip clogging or the like and to perform a smooth drilling process.

Here, for example, as described above, in the case where the shape of the outer peripheral chip breaker is depressed from the rake face with respect to the inner peripheral chip breaker, the bending of the outer peripheral chip breaker causes the inner peripheral chip breaker to be bent. Therefore, relatively long chips generated by the outer peripheral side cutting edge chip are slid into contact with the outer peripheral side chip breaker, are curled small, and are finely divided. Therefore, by adopting such a configuration, it becomes possible to effectively prevent chip clogging of chips by the outer peripheral side cutting edge tip.

[0013]

1 to 4 show an embodiment of the chip of the present invention. In these figures, the chip body 1
Reference numeral 1 denotes a flat-plate-like positive tip formed of a hard material such as a cemented carbide and having a substantially equilateral triangle in plan view. One surface forming the equilateral triangle in plan view is a rake face 12, and the rake face is also provided. The surface forming an equilateral triangle on the opposite side to the surface 12 is a seating surface 13, and the rake surface 12 and three side surfaces arranged around the seating surface 13 are flank surfaces 1, respectively.
4 ... Here, the clearance angle α of the clearance surface 14
Is preferably set to 5 ° to 15 °, and is set to 7 ° in this embodiment. At the center of the chip body 11 in a plan view, a mounting hole 15 that penetrates the chip body 11 in the thickness direction is formed.

Each ridge of the rake face 12 is formed with a ridge cutting edge 16, and two nose cutting edges 17, 17 is formed in a V-shape. Here, the length C of the side edge cutting blade 16 is equal to the rake face 12.
Assuming that the diameter of the inscribed circle of the equilateral triangle formed by D is D, it is desirable that the diameter is 40% to 60% of 3 ^1/2 D.
50% of ^{1 /} 2D. The nose cutting edges 17, 17 are formed so as to be symmetrical with respect to the bisector of the apex of the equilateral triangle and have a nose angle β greater than the apex angle γ = 60 ° of the equilateral triangle. Have been. The nose angle β is desirably set to 100 ° to 120 °, and is set to 100 ° in the present embodiment.

Further, a nose round blade 18 is formed at the intersection of the nose cutting blades 17, 17, that is, at the apex of each of the tops. Here, the radius of curvature R ₁ of the nose radius edge 18 is desirable set to 0.4 to 1.2 mm, in the present embodiment is set to 0.8 mm. Furthermore, the intersections between the Henryo portion cutting 16 and the nose portion cutting blade 17 is formed with a cutting edge between the rounded edge 19, the radius of curvature R ₂ is made to 0.2~0.8mm I have.

On the other hand, a breaker section 20 is formed inside the chip in a plane view of the rake face 12 so as to rise one step from the rake face 12. The breaker portion 20 rises from a position recessed substantially inward in the chip from the peripheral edge of the rake face 12 in a plan view, and then continues to the breaker upper face 21 parallel to the rake face 12 and the seating face 13. As a result, the outer shape of the breaker portion 20 in plan view presents an equilateral triangle substantially similar to the outer shape of the rake face 12. The portion that rises from the rake face 12 toward the breaker upper face 21 is an inclined face from the rake face 12 side to the chip thickness direction toward the breaker upper face 21 as going inward of the chip. The surface forms a breaker wall surface 22 which slides on the chip to curl the chip. Incidentally, the inclination angle δ formed by the breaker wall surface 22 with respect to the chip thickness direction is set to 60 ° in this embodiment.

Further, from the peripheral edge of the rake face 12 where the respective cutting blades are formed to the peripheral edge of the breaker portion 20, a portion which orbits the peripheral edge of the rake face 12 with a substantially constant width in a plan view is included in this planar view. In a predetermined circumferential direction (clockwise direction in the present embodiment) around the mounting hole 15, the nose is formed from the inside of the tip of the nose round blade 18 located at each top of the equilateral triangle formed by the rake face 12. Nose cutting edge 17 connected to radius blade 18, radius edge 19 between cutting edges,
Along the edge ridge cutting edge 16, a concave groove 23 is formed which is depressed so as to be lowered one step from the rake face 12 to the inside of the chip substantially at the center of the edge ridge cutting edge 16.

Here, as shown in FIG. 4, the bottom of the groove 23 goes from the periphery of the rake face 12 toward the inside of the chip, and sits on the rake face 12 via a land portion 24 of a very small width which is flush with the rake face 12. The breaker portion 20 extending from the rake face 12 to the bottom face parallel to the rake face 12 and extending into the concave groove 23 after being connected to the inclined face 25 inclined toward the face 13 side. Is formed so as to be continuous with the breaker wall surface 22. Therefore, this inclined surface 25
Is equal to the inclination angle of the inclined surface 25 with respect to the rake surface 12 in this embodiment. Incidentally, in the present embodiment, the inclination angle φ is set to 20 °. The breaker wall 22 of the breaker section 20
The portion connected to the concave groove 23 is a portion 22a connected to the inside of the tip of the side ridge cutting blade 16 and a portion 22b connected to the inside of the tip of the nose portion cutting blade 17 in plan view, as shown in FIG. As described above, each chip is formed in the shape of a concave curved surface depressed toward the inside of the chip.

In the chip having such a configuration, the rake face 1
2 at each apex of the equilateral triangle, a pair of nose cutting edges 17 and 1 are provided on both sides of the nose radius blade 18 with a nose radius blade 18 formed at the vertex therebetween.
7. Round blades 19 between cutting edges 19 and edge cutting edge 1
6, 16 would be formed symmetrically with respect to the top bisector.

The pair of nose cutting blades 17,
17, round blades 19 between cutting edges 19, and edge cutting edge 1
Of the nose round blades 18, the nose part cutting blades 17 and the inter-cutting round blades 19, which extend from the vicinity of the nose round blade 18 to one side of the nose round blade 18 (the counterclockwise direction in FIG. 1), Similarly, this one side edge cutting edge 1
6, the inside of the chip in a plan view of the portion up to the substantially central portion (the range indicated by the symbol M in FIG. 1) is provided with the breaker wall 2
A chip breaker connected to 2 is formed.
Thus, the chip breaker connected to the inside of the nose portion cutting edge 17, the cutting edge round edge 19, and the side ridge portion cutting edge 16 on one side is the inner peripheral side chip breaker 27 in this embodiment. .

On the other hand, the nose radius blade 1 at each vertex
8, the other side of the nose radius blade 18 (FIG. 1)
Along the nose part cutting edge 17 and the inter-cutting edge blade 19 which are connected in the clockwise direction in FIG. (Indicated range) inside the chip in plan view,
The breaker wall 22 from each cutting edge via the groove 23
(22a, 22b), a chip breaker having a shape different from that of the inner peripheral side chip breaker 27 is formed. The chip breaker connected to the inside of the chip of the nose portion cutting edge 17, the inter-cutting edge blade 19, and the side edge cutting edge 16 on the other side is the outer peripheral side chip breaker 28 in the present embodiment. .

Next, an embodiment of a throw-away type drilling tool using the insert having such a configuration as the outer peripheral side cutting edge tip and the inner peripheral side cutting edge tip will be described with reference to FIGS. . In these figures, the tool body 31
Is formed of steel or the like, and has a multi-stage cylindrical shape whose diameter is reduced toward the tip side in the direction of the axis O, and the base end side is a shank portion 32 for mounting the tool main body 31 to the spindle end of the machine tool. In addition, two chip discharge grooves 33, 33 extending along the axis O are formed on the front end side on opposite sides of the axis O. The tip mounting seats 3 are provided at the tips of the chip discharge grooves 33, 33, respectively.
4 and 34 are formed. Further, the chips of the above-described embodiment having the same shape and the same size are mounted on the chip mounting seats 34 and 34, and the inner peripheral side cutting edge chip 3 is mounted on one of the chip mounting seats 34.
5, and the other tip mounting seat 34 is removably mounted as an outer peripheral cutting edge tip 36 by clamp screws 37, 37 inserted into the mounting holes 15, respectively.

FIG. 7 shows the rotation locus of the inner peripheral cutting edge tip 35 and the outer peripheral cutting edge tip 36 in a plane including the axis O. As shown in this figure, the inner peripheral side cutting edge tip 35 has a pair of nose part cutting edges 17, 17 arranged on both sides of one top of the rake face 12 with the nose round blade 18 interposed therebetween. Among the round blades 19, 19 and the side ridge cutting blades 16, the nose section cutting blade 17 on one side, the round blade 19 between the cutting blades, and the side ridge cutting blade 1.
Reference numeral 6 denotes a bottom edge, and one nose edge 17 is disposed on the inner peripheral side of the one edge ridge 16.

Also, in the inner peripheral side cutting edge tip 35, there is one inter-cutting edge formed at the intersection of one of the bottom edge cutting edges 16 and one nose cutting edge 17. The blade 19 includes the one side edge cutting edge 16 and the nose cutting edge 1.
7 is provided so as to protrude toward the front end side in the direction of the axis O. Therefore, the one side edge cutting blade 16 is attached to the tool body 31.
The one nose portion cutting edge 17 is arranged so as to be inclined toward the base end side in the direction of the axis O as it goes toward the outer peripheral side of the tool body 31. It will be arrange | positioned so that it may incline toward the end side. In addition, this inner peripheral side cutting edge tip 35 is
A nose round blade 18 adjacent to the one nose cutting edge 17 serving as a bottom blade is disposed so as to be over-centered beyond the axis O.

On the other hand, the outer peripheral cutting edge tip 36 has a pair of nose cutting edges 17, 17, which are arranged on both sides of one top of the rake face 12 with the nose round blade 18 interposed therebetween.
Round blades 19, 19 between cutting edges, and edge cutting edges 16, 1
6, the nose portion cutting edge 17, the inter-cutting edge blade 19, and the edge ridge cutting edge 16 on the other side are bottom blades. Nose cutting edge 1
7 are located. Also in the outer peripheral side cutting edge tip 36, the other inter-cutting edge blade 19 at the intersection of the other side edge cutting edge 16 serving as the bottom edge and the other nose portion cutting edge 17 is also the other edge cutting edge. Are arranged so as to protrude further in the direction of the axis O than the side ridge cutting edge 16 and the nose cutting edge 17. Therefore, the other side ridge cutting blade 16 and the nose cutting blade 17 are respectively provided with a tool. The main body 31 is arranged so as to be inclined toward the base end side in the axis O direction toward the inner peripheral side or the outer peripheral side of the main body 31. In the outer peripheral side cutting edge tip 36, the nose portion cutting edge 17 on one side adjacent to the other nose portion cutting edge 17 serving as a bottom edge via a nose radius blade 18 is attached to the tool main body 31. The clearance angle ε is given to the axis O toward the radially inner peripheral side toward the rear end side in the axis O direction.

Thus, one edge ridge 16 serving as the bottom edge of the inner peripheral edge tip 35 and the other edge ridge 16 serving as the bottom edge of the outer edge tip 36 are provided. Are arranged so as to intersect with each other at an intersection P located substantially at the center of each of the side edge cutting blades 16 on a plane including the axis O. Further, the inner peripheral side cutting edge tips 3 which are disposed so as to protrude toward the front end side in the direction of the axis O, respectively.
5. One of the inter-cutting edge round blades 19 and the outer peripheral side cutting edge tip 36
The other inter-cutting edge blade 19 is an imaginary straight line L perpendicular to the axis O in a rotation locus on a plane including the axis O.
They are arranged so as to coincide with each other above, that is, the positions of the round blades 19 between the cutting edges in the direction of the axis O are set to be equal to each other. Further, in the present embodiment, as one goes toward the outer peripheral side or the inner peripheral side of the tool main body 31, one of the side edge cutting edges 16 of the inner peripheral side cutting edge tip 35 inclined toward the base end side in the direction of the axis O and The inclination angles θ that the other side edge cutting edge 16 of the outer peripheral side cutting edge tip 36 makes with the virtual straight line L are set to be equal to each other.

In the throw-away type drilling tool having such a configuration, the portion of the inner peripheral cutting edge tip 35 that is connected to the inner peripheral chip breaker 27 on the inner peripheral side of the tool body 31 with respect to the intersection point P is described. One side ridge cutting edge 16, a portion of one nose cutting edge 17 located on the inner peripheral side thereof up to the axis O, and one inter-cutting edge blade 19 formed at the intersection thereof. Will be used as a bottom blade. That is, in one chip, the one side edge cutting blade 16, the nose cutting blade 17, which is formed on each top of the rake face 12 as the inner peripheral side cutting blade tip 35,
When the round blade 19 between the cutting edges is used, the portion provided for this use is in the range indicated by the symbol M in FIG. Further, in the outer peripheral side cutting edge tip 36, the other side ridge cutting edge 16 of the portion connected to the outer peripheral side chip breaker 28 on the outer peripheral side with respect to the intersection point P, and the other nose portion cutting edge located on the outer peripheral side thereof. The blade 17, the other inter-cutting edge round blade 19 formed at the intersection thereof, and the portion of the nose round blade 18 located on the outer peripheral side of the other nose portion cutting blade 17 are used as bottom blades. Will be offered. Therefore, one tip is used as the outer peripheral cutting edge tip 36 and the other side edge cutting edge 1 formed on each top of the rake face 12 is used.
6, when the nose portion cutting edge 17, the inter-cutting edge round blade 19, and the nose round edge blade 18 are used, the portion provided for this use is in the range indicated by reference numeral N in FIG.

Therefore, in this embodiment, as shown in FIG. 1, the cutting edge portion used when the tip is subjected to cutting three times as the inner peripheral cutting edge tip 35, and the outer peripheral cutting edge tip 36 The cutting edge portion used when the cutting is performed three times is continuous without overlapping with each other. That is, one chip can be used three times as the inner peripheral side cutting edge tip 35 and three times as the outer peripheral side cutting edge tip 36, so that a total of six reusable times are possible, and the rake face 12 is formed on the edge of the rake face 12. It is possible to use the cutting blades evenly and to improve the use efficiency of the chips to the utmost.

In the throw-away type drilling tool having the above-described configuration, the one side edge cutting edge 16, the nose cutting edge 17, which is the bottom edge of the inner peripheral cutting edge tip 35, and the radius between the cutting edges. As described above, an inner peripheral chip breaker 27 that extends from the rake face 12 to the breaker wall surface 22 of the breaker section 20 is formed inside the tip of the blade 19, and serves as a bottom blade of the outer peripheral cutting tip 36. The other side ridge cutting edge 16, the nose cutting edge 17, the inter-cutting edge 19,
Inside the tip of the nose radius blade 18, an outer peripheral chip breaker 28 having a different shape from the inner peripheral chip breaker 27 is formed, so that the inner peripheral cutting chip 35 and the outer peripheral cutting chip 27 are formed. It is possible to cope with the chips having different properties generated by the same type of chip with one kind of chip.

That is, in the chip of the above embodiment, the inner peripheral chip breaker 27 has the rake face 1 as shown in FIG.
This is a breaker having a one-step bend from the second to the breaker wall surface 22. The bend is relatively small, while the outer chip breaker 28 has a rake face 1 as shown in FIG.
2 is a breaker that bends in multiple steps from the land 26 that is flush with the surface of the groove 23 to the breaker wall surface 22 that extends into the groove 23 through the inclined surface 25 and the bottom surface 26 of the groove 23. Becomes For this reason, according to the throw-away type drilling tool having the above-mentioned configuration equipped with such a chip, the relatively long chip generated by the outer-side cutting edge tip 36 is not removed by the outer-side chip breaker 28.
As a result, the sheet is curled into small pieces and is cut into small pieces, so that chip clogging or the like due to such long chips can be prevented beforehand and smooth drilling can be performed.

In addition, in the chip of the present embodiment, a portion of the breaker wall surface 22 of the breaker portion 20 which continues to the concave groove 23 of the outer peripheral chip breaker 28 has the edge ridge cutting blade 16 as described above. Part 2 connected inside the chip
2a and a portion 22 of the nose portion cutting edge 17 that continues inward of the tip
and b, each is formed in a concave curved surface shape recessed toward the inside of the chip. Thus, the chip generated by the other side edge cutting edge 16 of the outer peripheral side cutting edge tip 36 and the chip generated by the other side nose portion cutting edge 17 are each separated by a breaker after rubbing the groove 23. Wall 2
2 slidably comes into contact with the portions 22a and 22b and is curled in the width direction. For this reason, according to the indexable drilling tool of the present embodiment, the outer peripheral side cutting tip 36
Thus, the chips generated by the method can be more smoothly separated, and the advantage that chip clogging can be prevented more effectively can be obtained.

By the way, in the drilling process using such a drilling tool having a bottom blade, the rotation speed becomes slower toward the inner peripheral side of the bottom blade, and accordingly, the cutting load acting on the cutting blade increases. Is known to be. On the other hand, in the present embodiment, since the inner peripheral side chip breaker 27 is a chip breaker extending directly from the rake face 12 to the breaker wall surface 22, the one side edge cutting edge connected to the inner peripheral side chip breaker 27 is provided. 16, round blade 19 between cutting edges,
The nose cutting edge 17 has the other side ridge cutting edge 16 connected to the outer peripheral side chip breaker 28, the inter-cutting edge blade 19, as long as there is no depression by the inclined surface 25 of the concave groove 23.
And the nose portion cutting edge 17 is formed at a larger included angle. Therefore, according to the throw-away type drilling tool having the above-mentioned configuration in which such a chip is mounted, the chip is cut by the outer-side chip breaker 28 which is depressed from the rake face 12 in the outer-side cutting edge tip 36, while the inner chip is cut. In the peripheral cutting edge tip 35, each of the cutting edges 16, 17,
The blade edge strength of 19 can be maintained, and it is possible to prevent the cutting edge from being broken against a large cutting load as described above.

In this embodiment, the chip body 11 is formed so as to form a substantially equilateral triangle in plan view from the rake face 12 side. May be formed in a parallelogram shape or a rhombus shape having a pair of nose cutting edges, an inter-cutting-edge cutting edge, and a top provided with a side edge cutting edge, respectively. However, when such a configuration is adopted, the seating area of the chip body can be increased while the lengths of the respective cutting blades are made equal, so that the seating stability of the chip is improved, The advantage is that the dawn accuracy can be increased.

[0034]

According to the present invention as described above,
Edge cutting edge, nose cutting edge on one side of one chip,
And the inner peripheral side chip breaker is formed on the rake face connected to the round edge between the cutting edges, and the inner ridge cutting edge, the nose portion cutting edge, and the inner side on the rake face connected to the round edge between the cutting edges. By forming an outer peripheral chip breaker with a different shape from the peripheral chip breaker, when such a chip is used for a throw-away type drilling tool, the inner peripheral side cutting tip and the outer peripheral side cutting chip It is possible to provide chip breakers of different shapes to each bottom blade. And, while maintaining the high use efficiency of the chip, to prevent the occurrence of chip clogging and the like corresponding to the chips generated in different properties on the inner peripheral side and the outer peripheral side of the bottom blade,
Smooth drilling can be performed.

[Brief description of the drawings]

FIG. 1 shows a rake face 12 of a chip showing one embodiment of the present invention.
It is a top view from the side.

FIG. 2 is a sectional view taken along line XX of the embodiment shown in FIG.

FIG. 3 is a YY sectional view of the embodiment shown in FIG. 1;

FIG. 4 is a ZZ cross-sectional view of the embodiment shown in FIG.

FIG. 5 is a side view showing an example of a throw-away type drilling tool using the embodiment shown in FIG.

FIG. 6 is an enlarged side view of the tip of the indexable drilling tool shown in FIG. 5; (However, this is a diagram viewed from the opposite side to FIG. 5)

7 is a diagram showing a rotation locus on a plane including the axis O of the outer peripheral side cutting edge tip 36 and the inner peripheral side cutting edge tip 35 in the throw-away type drilling tool shown in FIG.

FIG. 8 is a side view showing the tip of a conventional throw-away drilling tool.

9 is a diagram showing a rotation locus on a plane including an axis O of the inner peripheral side cutting edge tip 2 and the outer peripheral side cutting edge tip 3 of the conventional example shown in FIG.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 11 Chip main body 12 Rake surface 16 Edge cutting edge 17 Nose part cutting edge 18 Nose round blade 19 Round blade between cutting edges 20 Breaker part 22, 22a, 22b Breaker wall surface 23 Groove 27 Inner peripheral side chip breaker 28 Outer peripheral side chip Breaker 31 Tool main body 35 Inner peripheral side cutting edge tip 36 Outer peripheral side cutting edge tip O Rotation axis L of tool main body 31 It is perpendicular to axis O and passes through the tip of round edge 19 between cutting edges of each cutting edge tip 35, 36. Virtual straight line P Intersection point of edge ridges 16, 16 serving as the bottom edge of each cutting edge tip 35, 36 M Used as inner peripheral side cutting edge tip 35 of each cutting edge portion formed in tip body 11 Provided portion N A portion provided for use as outer peripheral cutting edge tip 36 of each cutting edge portion formed in tip body 11 δ Breaker wall surface 22 extends in the chip thickness direction The inclination angle φ formed by the inclined surface 25 of the groove 23 with respect to the bottom surface 26 The inclination formed by the imaginary straight line L and the edge ridge cutting edge 16 serving as the bottom blade of each of the cutting tips 35 and 36. Corner

Continuation of the front page (56) References JP-A-63-260715 (JP, A) JP-A-63-131311 (JP, U) (58) Fields investigated (Int. Cl. ⁷ , DB name) B23B 51 / 00

Claims (3)

(57) [Claims] A rake face is formed on at least one surface of the polygonal flat chip body that forms the polygon, and a pair of edge ridges connected to at least one apex of the rake face are edge ridge cutting edges. Is formed, and a pair of nose cutting blades are formed on the one apex, which are symmetric with respect to the bisector of the apex and have an angle larger than the apex angle of the apex. A nose round blade is formed at the intersection of the nose cutting blades, and a round blade between the cutting edges is formed at the intersection of the side ridge cutting blade and the nose cutting blade. One of the ridge cutting edges and one nose cutting edge adjacent to the one side ridge cutting edge have an inner peripheral tip on the rake face connected to the inside of the tip. A breaker is formed, and the other side edge cutting edge of the pair of side edge cutting blades is formed. An outer peripheral chip breaker having a shape different from that of the inner peripheral chip breaker is formed on the rake face connected to the inside of the chip between the blade and the other nose cutting edge adjacent to the other side edge cutting blade. A throwaway tip characterized by being made. 2. The throw-away chip according to claim 1, wherein the outer chip breaker is a chip breaker depressed from the rake face with respect to the inner chip breaker. 3. An inner peripheral cutting edge tip forming a central portion of a bottom blade and an outer peripheral cutting edge tip forming an outer peripheral portion of a bottom blade are attached to and detached from a tip end portion of a tool body rotated about an axis. 3. The indexable drilling tool according to claim 1, wherein the inner peripheral side cutting edge tip and the outer peripheral side cutting edge tip have the same shape and size. In the inner peripheral side cutting edge tip, the one edge cutting edge and one nose cutting edge are bottom edges, and the one nose cutting edge is connected to the one edge cutting edge. While being located on the inner peripheral side of the blade, one of the edge cutting edges located at the intersection of the one side edge cutting edge and one nose portion cutting edge is projected to the axial direction tip side, and The nose radius blade adjacent to the one nose cutting edge extends beyond the axis. The outer peripheral side cutting edge tip is arranged so as to be a bar center, and the other side edge cutting edge and the other nose portion cutting edge are bottom edges, and the other nose portion cutting edge is provided. Is positioned on the outer peripheral side of the other side ridge cutting edge, and the other cutting edge round blade located at the intersection of the other side ridge cutting edge and the other nose portion cutting blade in the axial direction. The one nose cutting edge adjacent to the other nose cutting edge via the nose radius blade is projected toward the distal end side, and is directed toward the inner peripheral side of the tool body as the axial direction is directed toward the base end side. The outer peripheral side cutting edge tip and the inner peripheral side cutting edge tip are further arranged as follows.
The one edge cutting edge and the other edge cutting edge intersect with each other on a rotation locus on a plane including the axis, and the one edge cutting edge and the other edge cutting edge are both intersecting. Are arranged so as to coincide with one virtual straight line perpendicular to the axis.