JP2001191205A - Throw away type drilling tool - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a drilling tool capable of performing economical and efficient drilling by making it possible to cope with cases of only extremely slightly different inside diameters of a working hole only by replacing throw away tips without preparing a plurality of drilling tools and replacing all the tool bodies. SOLUTION: On a tip mounting seat 11A formed at a tip of a tool body 1, plural kinds of throw away tips 12, 13 in which the sizes of inscribed circles each other of polygonal surfaces made into cutting faces 12A, 13A are made equal, crossed angles each other of a pair of adjacent side surfaces are made equal and corner parts C located on tool outer peripheral sides of at least cutting edges 14, 15 are made to have different sizes can be mounted.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a cutting tool having a pair of insert mounting seats formed at the tip of a tool body, each of which has a cutting edge protruding toward the tip of the tool. Removably mounted indexable drilling tool (hereinafter referred to as drilling tool)
It is about.

[0002]

2. Description of the Related Art As a drilling tool of this type, for example, as shown in FIGS. 5 to 7, an axial line O on the outer periphery of a tip end of a substantially cylindrical tool body 1 having an axis O as a center is interposed. On the opposite side, a pair of chip discharge grooves 2 are formed, which extend from the front end of the tool body 1 toward the rear end of the tool in the direction of the axis O and are gently twisted rearward in the tool rotation direction T. Wall 2A facing the tool rotation direction T at the end of the groove 2 or 2
A pair of chips 4 and 4 are known that have their cutting blades 5 protruding toward the tool tip side and are detachably mounted by clamp screws 6 on the chip mounting seats 3A and 3B formed on the base. The shank 7 is formed at the rear end of the tool body 1, and a supply path 8 for cutting oil or the like is formed along the axis O from the rear end face. The tool body 1 is branched into two and opened at the tip end surface of the tool body 1.

[0003] The chip 4 is a positive chip having a substantially rhombic flat plate shape, and one of the rhombic surfaces has a rake face 4A.
The cutting edge 5 is formed on all the side edges of the rake face 4A, and a mounting hole 4B through which the clamp screw 6 is inserted is formed at the center of the rake face 4A. It is formed so as to penetrate in the thickness direction. Of the four corners of the diamond-shaped rake face 4A, a pair of acute corners C, C are formed so that the tips of the cutting blades 5, 5 extending toward each corner C are bent at an obtuse angle. Thus, the corner cutting edges 5A, 5A, which form a convex V shape symmetrically with respect to a diagonal line connecting the pair of corners C, C.
5A are formed.

On the other hand, the tip mounting seats 3A and 3B are formed so as to be biased toward the outer peripheral side of the tool and the inner peripheral side of the tool.
A bottom surface 3a which is recessed from A and faces the tool rotation direction T side and has a clamp screw hole into which the clamp screw 6 is screwed, and a wall surface 3b rising from the bottom surface 3a and facing the tool tip side, It is defined by a wall surface 3c that rises with respect to the bottom surface 3a, faces the outer peripheral side of the tool rear end, and extends in a direction intersecting at an acute angle with respect to the wall surface 3b. And
The wall surfaces 3b and 3c are formed in a direction intersecting at a crossing angle equal to a pair of side surfaces extending in a direction crossing at an acute angle toward the corner portion C among the side surfaces connected to the cutting edge 5 of the chip 4, and In order to avoid interference with the side surfaces of the chip 4 connected to the corner cutting edges 5A, 5A intersecting the corners C, the wall surfaces 3b, 3c can be brought into contact with the pair of side surfaces. Is formed so as to leave an interval between the chip discharge groove 2 and the wall surface 2B facing the rear side in the tool rotation direction T.

[0005] Further, the tip mounting seat 3 biased toward the inner peripheral side of the tool.
B is a bottom surface 3e in which a clamp screw hole is formed also facing the tool rotation direction T side, and a wall surface 3f facing the tool tip side.
And a wall surface 3g extending in a direction intersecting the wall surface 3f at an obtuse angle and facing the outer peripheral side of the tool tip.
These wall surfaces 3f, 3g are formed in a direction intersecting at an angle equal to the intersection angle of a pair of side surfaces intersecting at an obtuse angle among the side surfaces connected to the cutting edge 5 of the chip 4, and can contact the pair of side surfaces. It has been. As shown in FIG. 7, the portion of the wall surface 3g facing the outer peripheral side of the tool tip on the tool tip side extends beyond the axis O as viewed from the tool tip side.
It is formed so as to protrude to the A side. Furthermore, the corner where these wall surfaces 3f and 3g intersect also has the wall surface 3f.
An escape portion 3h is formed to avoid interference with the intersection of the pair of side surfaces of the chip 4 abutting on f and 3g.

The chip mounting seats 3A, 3A,
3B, the chips 4 and 4 have the same shape and the same size, with the rake face 4A directed in the tool rotation direction T and the pair of side faces on the wall faces 3b and 3c and the wall faces 3f and 3g. The cutting edge 5 and the corner cutting edge 5A connected to the side surface opposite to the side surface abutting on the wall surfaces 3b and 3f are mounted so as to protrude toward the tool tip side. In addition, these chips 4 and 4
A chip 4 attached to one of A and 3B is turned around the center of the mounting hole 4B, so that the rake face 4
A, a cutting edge 5 formed on a pair of mutually opposing side edges
5 and the corner cutting edges 5A, 5A can protrude toward the tool tip side, and this tip 4
A and 3B can be attached to the other of the chip mounting seats 3A and 3B, and the other of the chip mounting seats 3A and 3B is further turned around the mounting hole 4B and remounted, so that the other pair of side ridges of the rake face 4A can be mounted. The formed cutting edges 5, 5 and the corner cutting edges 5A, 5A can protrude toward the tool tip side, and thus the cutting edges 5,... And the corner cutting edges formed on the four side ridges. 5A can be used evenly.

In the state where the chips 4, 4 are mounted on the chip mounting seats 3A, 3B, the chip 4 mounted on the chip mounting seat 3A has an outer periphery of a corner cutting edge 5A protruding toward the tool tip side. The end, that is, the protruding end of the corner portion C, protrudes outward from the outer periphery of the tip end portion of the tool body 1, and the diameter of a circle formed by the outer peripheral end around the axis O is the outer diameter of the cutting edge 5 of the drilling tool. D. The tip 4 attached to the tip mounting seat 3B has the inner peripheral end of the corner cutting edge 5A protruding toward the tool tip side, that is, the protruding end of the corner C exceeding the axis O, and the tip mounting seat 3A. The cutting lobes 5, 5 projecting toward the tool tip side of the tips 4, 4 are arranged so that the rotation trajectories around the axis O are continuous with each other in the radial direction.

[0008]

By the way, in such a drilling tool, the size of the chips 4, 4 that can be mounted on the chip mounting seats 3A, 3B is limited to the size of the chip mounting seat 3.
Since the distances between the clamp screw holes formed on the bottom surfaces 3a and 3e of the A and 3B and the wall surfaces 3b and 3c and the wall surfaces 3f and 3g are constant, the size of each of the tool bodies 1 is usually set in accordance with this. Have been. In particular, in the drilling tool having the above-described configuration, one chip 4 can be mounted on both of the chip mounting seats 3A and 3B as described above, and the chip mounting seats 3A and 3B are turned around the center of the mounting hole 4B. The cutting edges 5 and the corner cutting edges 5A formed on all four side edges of the rake face 4A can be used evenly by being attached even if it is done. In order to obtain the effect, these chips 4 and 4 must be of the same shape and the same size. For this reason, in the above-mentioned conventional drilling tool, for example, even when drilling a processing hole whose inner diameter is only slightly different, a drilling tool having an outer diameter D corresponding to each inner diameter is prepared. In this case, the drilling operation has to be performed while replacing the tool body 1 with the machine tool, so that it is unavoidable that the drilling operation becomes extremely uneconomical and inefficient.

The present invention has been made in view of such circumstances, and in particular, even in the case where the inside diameters of the machined holes are very slightly different as described above, a plurality of types of drilling tools are prepared and these tools are used. An object of the present invention is to provide a drilling tool capable of performing economical and efficient drilling, which can be dealt with only by exchanging a chip without replacing the entire body.

[0010]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems and to achieve such an object, the present invention relates to a method of manufacturing the above-described apparatus, comprising the steps of: A chip discharge groove extending in the direction is formed.A chip is inserted into a chip mounting seat formed on a wall face of the tip of the chip discharge groove that faces the tool rotation direction. A drilling tool in which a corner portion of a cutting edge located on a tool outer peripheral side is protruded from an outer periphery of a tip end portion of the tool main body and is detachably attached. With the square face as the rake face, the cutting edge is formed at a side ridge of the rake face, and the tip mounting seat includes a pair of wall faces that can abut a pair of adjacent side faces of the tip, With a rake face on the tip mounting seat The sizes of the inscribed circles of the polygonal surfaces are equal, and the intersection angles of the pair of adjacent side surfaces are equal to each other, and at least the corner portions located on the tool outer peripheral side of the cutting edge have different sizes. A plurality of different types of chips can be attached.

Therefore, in the drilling tool configured as described above, the size of the inscribed circle of the polygonal surface, which is a rake face, and the wall of the chip mounting seat are brought into contact with each other among the plurality of types of chips. Since the intersection angle of the pair of side surfaces of the chip to be set is equal, the mounting position of the chip on the chip mounting seat does not change.For example, even if the mounting hole is formed in the chip and screwed with a clamp screw, it is mounted. There is no displacement between the hole and the clamp screw hole. In these types of inserts, the corners located on the outer peripheral side of the cutting edge of the cutting edge are different in size. The turning diameter, ie the outer diameter of the cutting edge, can be of different sizes.

Here, as in the above-mentioned conventional drilling tool, the chip has a substantially rhombic flat plate shape, and one of the rhombic surfaces is the rake surface. In the case where the cutting edge having the pair of acute angle portions of the surface as the corner portion is formed, the cutting edge formed on at least the pair of opposite side ridges of the rake face is obtained by inverting the tip. In order to be able to be used evenly, the tip mounting seat biased toward the outer peripheral side of the tool is provided with the pair of wall surfaces extending in directions intersecting at an acute angle with each other toward the outer peripheral side of the tool front end and the outer peripheral side of the tool, These wall surfaces can be brought into contact with a pair of side surfaces adjacent to one of the corner portions among the side surfaces of the chip, and the chip mounting seat has the plurality of types in which the pair of corner portions have different sizes. Chips on the other The corner portion is protruded on the tool periphery side may be capable of being mounted. Further, between the pair of wall surfaces of the chip mounting seat, a relief portion capable of accommodating the one corner portion of the chip is formed so as to reach a wall surface of the chip discharge groove which faces rearward in the tool rotation direction. In addition, even a chip having a large corner can be securely mounted on the chip mounting seat.

[0013]

1 to 4 show an embodiment of the present invention. The same parts as those of the conventional drilling tool shown in FIGS. 5 to 7 are denoted by the same reference numerals. Simplify the description. That is, also in the drilling tool of this embodiment, a pair of chip discharge grooves 2 and 2 are provided on the outer periphery of the tip end of the tool body 1 on opposite sides of the axis O and from the tip of the tool body 1 along the axis O. Are formed so as to be gently twisted rearward in the tool rotation direction T while extending toward the tool rear end side in the direction. 2A, a tip mounting seat 11A biased toward the tool outer peripheral side and a tip mounting seat 11B biased toward the tool inner peripheral side are formed. As shown in FIGS. 1 and 2 and FIGS. 3 and 4, a pair of chips 12, 12 and 13 each having the same shape and the same size are provided on these chip mounting seats 11A and 11B. , 13 can be attached, that is, a plurality (two in this embodiment) of chips 12, 13 can be attached.

Each of these chips 12 and 13 is a positive chip formed in a substantially rhombic flat plate shape from a hard material such as a cemented carbide, and one of the rhombic surfaces is a rake surface 12A, 13A. This rake face 12A,
Cutting edge 14 and cutting edge 15 at all four sides of 13A
Are formed, and the respective cutting blades 14, 15,.
The rake faces 12A and 13A form a pair of corners C and C on the side of the corners C and C, respectively.
A and 15A are formed so as to intersect at an obtuse angle with respect to the cutting edges 14 and 15, and a pair of corner cutting edges 14A and 14A and a corner cutting edge 1 located at one corner C are formed.
5A and 15A are symmetrical to each other with respect to a diagonal line connecting the pair of corners C and C, and the corner cutting edges 14
A and 15A are formed so as to intersect in a convex V-shape at an intersection angle larger than an intersection angle formed by an extension of the cutting blades 14 and 15 continuous to the corner portion C side. Also, rake face 12A,
At the center of 13A, mounting holes 12B and 13B through which the clamp screw 6 is inserted are formed so as to penetrate the chips 12 and 13 in the thickness direction.

Here, between the chips 12, 13, the portions of the rake faces 12A, 13A on which the corner cutting edges 14A, 15A are formed, excluding the corners C, C, have the same shape and size. Is formed, that is,
The mounting holes 12B and 13B are also formed in the same shape and size, and the size of the circle inscribed in the rhombus formed by the rake faces 12A and 13A around the mounting holes 12B and 13B is made equal. The cutting edges 14,..., 15.
Of the side surfaces 2 and 13, the crossing angles of the side surfaces of the portions connected to the cutting edges 14 and 15 are formed to be equal to each other. In the present embodiment, these chips 1
Between 2 and 13, the corner cutting edges 14A and 15A are the cutting edges 1
The intersection angles formed by the corner cutting edges 14A and 14A and the intersection angles formed by the corner cutting edges 15A and 15A are made equal to each other. Corner cutting edge 14A
Of the point of intersection where the
In the above, the corner portions C and C have different sizes because the position of the intersection where the corner cutting edge 15A intersects the cutting edge 15 is different.

That is, the chip 1 shown in FIGS.
2, the cutting edge 14 is bent at a relatively early stage in the middle of extension to the corner portion C side to form a corner portion cutting edge 14A, and the length of the cutting edge 14 up to the intersection with the corner portion cutting edge 14A. Is relatively short and the length of the corner cutting edge 14A from this intersection to the tip of the corner C is relatively long, whereas the cutting edge 1 in the tip 13 shown in FIGS.
5 is bent at a position relatively close to the protruding end of the corner portion C and continues to the corner portion cutting edge 15A, and the length of the cutting edge 15 to the intersection with the corner portion cutting edge 15A is longer than the tip 12 described above. Conversely, the length of the corner cutting edge 15A from the intersection to the tip of the corner C is shorter than the tip 12. Accordingly, the length of the diagonal line connecting the protruding ends of the corner portions C, C is also changed with respect to the chip 12 by the chip 1.
Therefore, the length from the center of the mounting hole 13B of the chip 13 to the protruding end of each of the corners C, C is also longer from the center of the mounting hole 12 of the chip 12 to each of the corners C, C.
It is longer than the length to the tip.

On the other hand, the tip mounting seats 11A and 11B to which the plurality of types of chips 12 and 13 are mounted have substantially the same configuration as the tip mounting seats 3A and 3B of the conventional drilling tool described above. That is, the tip mounting seat 11A biased toward the tool outer peripheral side is recessed one step from the wall surface 2A of the chip discharge groove 2 and faces the tool rotation direction T side, and has a bottom surface 11a in which a clamp screw hole into which the clamp screw 6 is screwed is formed. And a wall surface 11b rising from the bottom surface 11a toward the tool tip side, and a wall surface 11c rising from the bottom surface 11a toward the outer peripheral side of the tool rear end. Further, these wall surfaces 11b and 11c are portions of the side surfaces of the chips 12 and 13 that are continuous with the cutting blades 14 and 15 excluding a pair of side surfaces extending toward the corner portions C and C, excluding the corner cutting blades 14A and 15A. Are formed in directions intersecting each other at an acute angle so as to extend in a direction intersecting at an intersection angle equal to the intersection angle formed by the extension surface to the corner portion C side of
The tips 12 and 13 can be brought into contact with a pair of side surfaces connected to the cutting blades 14 and 15, respectively.

Also, the tip mounting seat 1 biased toward the tool inner peripheral side.
1B also has a bottom surface 11e facing the tool rotation direction T side, a wall surface 11f facing the tool tip side, and a wall surface facing the tool tip outer peripheral side formed so that the tool tip side protrudes beyond the axis O toward the tip mounting seat 11A side. 11g, and these wall surfaces 11f, 11g are the cutting edges 1 of the side surfaces of the chips 12, 13 except for the corner cutting edges 14A, 15A.
4, 15 are formed so as to intersect at an angle equal to the intersection angle between a pair of side portions intersecting at an obtuse angle at the corner portions other than the corner portions C and C, respectively. It is possible to abut. And the wall surfaces 11b of these chip mounting seats 11A and 11B,
Also at the corner where 11c and wall surfaces 11f and 11g intersect,
Relief portions 11d and 11h are formed, respectively.
1d is formed in a concave shape deeper on the corner side than the relief portion 3d of the conventional drilling tool, and particularly in the present embodiment, the wall surface 2B of the chip discharge groove 2 facing the tool rotation direction T rear side. , And can accommodate the corner portion C of the chip 13 having a long length up to the protruding end.

In the drilling tool configured as described above, the plurality of types of chips 12 and 13 are combined with the rake face 12.
A, 13A are inscribed circles of rhombic surfaces (polygonal surfaces) having the same size, and a pair of side surfaces adjacent to the corner portion C excluding the corner cutting edges 14A, 15A. The side surfaces connected to the blades 14 and 15 and the side surfaces intersecting and adjoining the corners other than the corners C also have the same crossing angles.
Since the escape portion 11d of A can also be accommodated in the corner portion C of the chip 13, the pair of side surfaces of the chips 12 and 13 can be attached to the wall surfaces 11b and 1 respectively.
1c and the wall surfaces 11f and 11g, and can be mounted on the chip mounting seats 11A and 11B by the clamp screws 6 and 6. In addition, in the drilling tool in which the chips 12 and 13 are respectively mounted, the chip mounting seat 1
The tips of the corners C located on the tool tip side of the chips 12 and 13 attached to 1A are made to protrude more toward the tool outer periphery than the outer periphery of the tool tip of the tool body 1, and the corners extending from this tip to the tool rear end side. While the outer cutting edges 14A and 15A are given an outer clearance angle, the protruding ends of the corners C located on the tool tip side of the chips 12 and 13 mounted on the chip mounting seat 11B slightly exceed the axis O. Further, the cutting blades 14 and 15 connected to the corners C and C and protruding toward the tip end of the tool are arranged so that the rotation locus around the axis O is continuous.

In the tip mounting seat 11A, which is biased toward the outer peripheral side of the tool, the center position of the mounting holes 12B and 13B remains unchanged regardless of whether the tip 12 or 13 is mounted. , Chips 12, 13
The size of the corner portion C is different between the two, and the length from the center to the tip of the corner portion C is longer in the tip 13 than in the tip 12, so that the corner portion C
The tip 13 also has a longer diameter of the circle formed by the tip of the tip 12 around the axis O, that is, as shown by the chain line in FIG.
Than the outer diameter D ₁₂ of the cutting edge 14 and the corner portion cutting edge 14A of the drilling tool when fitted with the outer cutting edge 15 and the corner portion cutting edge 15A when fitted with a chip 13 as shown by the solid line towards the diameter D ₁₃ is increased. Therefore, according to the drilling tool having the above-described configuration, it is possible to drill machining holes having different inner diameters by exchanging the tips 12 and 13 even for one type of the tool main body 1, and in particular, a large number of slightly different inner diameters. It is extremely economical when drilling a machined hole, and since the outer diameters D ₁₂ and D ₁₃ can be changed without removing the tool body 1 from the machine tool, efficient drilling work can be achieved. it can.

In the present embodiment, the chip 12,
13 has a rhombic flat plate shape, and the rake faces 12A,
Cutting edges 14 on all four sides of the diamond-shaped surface 13A
, 15 ... and corner cutting edges 14A, 15A are formed. On the other hand, the tip mounting seat 11A biased toward the outer peripheral side of the tool includes a wall surface 11b facing the front end side of the tool and an outer peripheral side of the rear end of the tool. And a wall surface 11c extending in a direction intersecting the wall surface 11b at an acute angle toward the wall surface 11b.
The b, 11c can be brought into contact with a pair of side surfaces connected to the cutting blades 14, 15 on the side surfaces adjacent to the sharp corners C, C among the side surfaces of the chips 12, 13. Therefore, in any of the chips 12 and 13, even if any of the corners C and C is directed toward the escape portion 11 d and the other is protruded toward the outer periphery of the tool, the chips 12 and 13 are attached to the mounting holes 12 B and 12 B. By inverting around the center of 13B, both the cutting edges 14, 15 and the corner cutting edges 14A, 15A formed on a pair of opposing sides of the rhombic surface formed by the rake faces 12A, 13A are on the tool tip side. And can be used for drilling.

Accordingly, in addition to this, for example, similarly to a conventional drilling tool, the tip mounting seat 11 biased toward the tool inner peripheral side.
B, the cutting blades 14 formed on the remaining pair of side edges,
15 and the corner portion cutting blades 14A and 15A can be used, so that the tip 1 having a different size of the corner portion C can be used.
No matter which of 2 and 13 is attached, the rake face 12
A, all cutting edges 14, 1 formed on the side edges of 13A
5 and the corner cutting edges 14A and 15A can be used evenly, which is more economical. Moreover, in the present embodiment, the wall surface 1 is formed on the tip mounting seat 11A.
An escape portion 11d formed between 1b and 11c is formed deeply so as to reach a wall surface 2B of the chip discharge groove 2 facing the rear side in the tool rotation direction T, and can accommodate a large corner portion C of the chip 13. Since the large corner portion C does not interfere with the chip mounting seat 11A, the chip mounting seat 11
A can be attached. Incidentally, since the size of the remaining pair of corner portions other than the corner portions C, C does not change between the chips 12, 13, the escape portion 1 formed between the wall surfaces 11f, 11g of the chip mounting seat 11B.
1g does not need to be as deep as the escape portion 11d.

In this embodiment, the chips 12, 13
Between the corners C, the intersection angles of the corner cutting edges 14A and 15A with the cutting edges 14 and 15 and the intersection angles of the corner cutting edges 14A and 15A are equal to each other. By making the positions of the intersections of the cutting edges 15A and the cutting blades 14 and 15 different, the lengths to the protruding ends of the corners C are different, and the corners C are different in size. It is also possible that the corners C between the chips 12 and 15 have different sizes after the crossing angles between the partial cutting edges 14A and 15A and between the cutting edges 14 and 15 are different.
However, in that case, these plural kinds of chips 12, 1
Since the angles of the corner cutting edges 14A and 15A with respect to the axis O are different between the three, the machining state may be changed, and the corners C of the chips 12 and 13 mounted on the chip mounting seat 11A may be changed. Since there is a possibility that a sufficient outer clearance angle may not be secured at the corner cutting edges 14A and 15A facing the tool outer peripheral side, even when the sizes of the corners C are different as described above, as in the present embodiment. Each intersection angle of the corner cutting edges 14A and 15A is the tip 1
These two or more kinds of chips 1
It is desirable that the corner portions C have similar shapes but have different sizes only between the two.

On the other hand, in the present embodiment, a plurality of types of chips 12, 13 are formed in a rhombic flat plate shape, and the pair of acute corners C, C have different sizes from each other. Besides, for example, a chip is formed in a substantially equilateral triangular flat plate shape, and a cutting edge is formed on a side ridge of the equilateral triangular surface which is a rake face, while the chip mounting seat of the tool main body has this chip. A pair of wall surfaces that can be brought into contact with the pair of side surfaces, and a cutting blade that continues to the remaining one side surface,
Is positioned on the outer peripheral side of the tool so as to protrude toward the tip end of the tool, and the size of the inscribed circles of the equilateral triangular surface, which is a rake face, is equal to the tip mounting seat, and the adjacent While the intersection angles of the pair of side surfaces are made equal to each other, at least the corner portions located on the outer peripheral side of the tool are made to have different sizes by forming corner cutting edges of different lengths on the corner portions. A plurality of types of chips may be attached. Also in this case, the tip mounting seats are formed on the tool outer peripheral side and the inner peripheral side, and the chips can be mounted by rotating the chips by 120 ° at each of the chip mounting seats. If one chip can be attached, 3 of the rake face
This makes it possible to use the cutting blades formed at the two ridges evenly.

[0025]

As described above, according to the present invention,
The size of the inscribed circles of the polygonal faces, which are rake faces, are equal to each other and the intersection angles of a pair of adjacent side faces are equal to each other, and at least the cutting edge is formed on the tip mounting seat formed at the tip of the tool body. A plurality of types of chips having different sizes can be attached to the corners located on the outer peripheral side of the tool. In particular, in the case of drilling a large number of drilled holes having slightly different inner diameters, it is extremely economical and the drilling work can be made more efficient.

[Brief description of the drawings]

FIG. 1 is a side view of a tip of a drilling tool to which a throw-away tip 12 is attached according to an embodiment of the present invention.

FIG. 2 is a front view of the embodiment shown in FIG. 1 as viewed from a tool tip side.

FIG. 3 is a side view of a tip of a drilling tool to which a throw-away tip 13 is attached according to an embodiment of the present invention.

FIG. 4 is a front view of the embodiment shown in FIG. 3 as viewed from a tool tip side.

FIG. 5 is a side view showing a conventional drilling tool.

6 is an enlarged side view of a tip portion of the conventional drilling tool shown in FIG.

FIG. 7 is a front view of the drilling tool shown in FIG. 6, as viewed from a tool tip side.

[Description of Signs] 1 Tool main body 2 Chip discharge groove 2A, 2B Wall surface of chip discharge groove 11A, 11B Chip mounting seat 11b, 11c, 11f, 11g Wall surface of chip mounting seat 11d, 11h Relief portion 12, 13 Throwaway tip 12A , 13A Rake face 14, 15 Cutting edge 14A, 15A Corner cutting edge C Corner part O Axis line of tool body 1 Tool rotation direction D ₁₂ Outer diameter when throw-away tip 12 is attached D ₁₃ Attach throw-away tip 13 Outer diameter when

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Yasuhiko Kawade 1528 Nakashinda, Yokoi, Kobe-cho, Anpachi-gun, Gifu Prefecture F-term in Mitsubishi Materials Corporation Gifu Works 3C037 AA00 BB15

Claims (3)

[Claims] 1. A chip discharge groove extending in the axial direction is formed on an outer periphery of a distal end portion of a substantially cylindrical tool body rotated around an axis, and a wall surface of a tip of the chip discharge groove facing a tool rotation direction. In the tip mounting seat formed in, the throw-away tip causes the cutting edge to protrude toward the tool tip side, and the corner portion of the cutting edge located on the tool outer circumference side protrudes from the tool tip outer circumference of the tool body. A throw-away type drilling tool that is detachably attached, wherein the throw-away tip is in the shape of a polygonal flat plate, and one of the polygonal surfaces is a rake face, and the edge of the rake face is a ridge. The cutting edge is formed, and the tip mounting seat has a pair of wall surfaces that can abut on a pair of adjacent side surfaces of the throw-away tip, and the tip mounting seat is a rake face. The sizes of the inscribed circles of the polygonal surfaces are equal, and the intersection angles of the pair of adjacent side surfaces are equal to each other, and at least the corner portion of the cutting edge located on the tool outer peripheral side has a different size. Characterized in that a plurality of types of indexable inserts can be attached. 2. The indexable insert has a substantially rhombic flat plate shape, and one of the rhombic surfaces is the rake face.
Along the edge of the rake face, the cutting edge is formed with the pair of acute angles of the rhomboid face as the corners,
The tip mounting seat is provided with the pair of wall surfaces extending in a direction intersecting at an acute angle with each other, facing the tool front end side and the tool rear end outer peripheral side, and these wall surfaces are one of side surfaces of the indexable insert. The corners of the plurality of types of throw-away chips, in which the pair of corners are different in size, can be brought into contact with a pair of side surfaces adjacent to each other. 2. The indexable drilling tool according to claim 1, wherein the corner portion can be mounted by projecting to the outer peripheral side of the tool. 3. An escape portion capable of accommodating the one corner portion of the throw-away tip is provided between a pair of wall surfaces of the tip mounting seat on a wall surface of the chip discharge groove facing rearward in the tool rotation direction. The indexable drilling tool according to claim 2, characterized in that it is formed so as to reach.