JP3468141B2 - Indexable insert and indexable drilling tool equipped with indexable insert - 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 mounted on a throw-away type drilling tool such as a throw-away type drill and a throw-away type drilling tool equipped with the throw-away tip.

[0002]

2. Description of the Related Art In drilling with a throw-away type drilling tool of this kind, since the cutting site by the cutting edge becomes the bottom of a closed drilling hole, the chips produced during cutting do not clog. If it occurs, it may cause a significant increase in cutting resistance, or the finished surface of the machined hole may be damaged.Therefore, the throw-away drilling tool used for such drilling requires excellent chip discharge performance. To be done. Then, as a throw-away type drilling tool that meets such a demand, for example, Japanese Patent Laid-Open No.
The one described in Japanese Patent Publication No. 150304 has been proposed.

FIG. 6 is a layout view of the above-described conventional throw-away tip and the tip end portion of the throw-away type drilling tool equipped with this throw-away tip as viewed from the side, and FIG. It is the front view which saw the away type drilling tool from the front end side. In this throw-away drilling tool 1, a blade portion 2 is provided on the tip end side of a shank portion (not shown), and an outer peripheral surface of the blade portion 2 extends from the tip end surface of the tool body 1a to the base end portion thereof with a rotation axis O therebetween. A pair of chip discharge grooves are formed so as to be located on opposite sides of each other. Tip mounting seats 3a and 3b are respectively formed at the tips of the wall surfaces of the pair of chip discharge grooves facing the tool rotation direction T side (counterclockwise in FIG. 7), and these chip mounting seats 3a and 3b are formed. Two throw-away tip chips 4 and 4 are removably attached to each by clamp screws. Here, one tip mounting seat 3a is on the inner peripheral side of the tool body 1a, and the other tip mounting seat 3a.
b are installed in a biased manner on the outer peripheral side of the tool body 1a. Along with this, the one throw-away tip 4 forming the inner blade tip 4a is biased toward the inner circumference side of the tool body 1a, and the other throw-away tip 4 forming the outer blade tip 4b is biased toward the outer circumference side of the tool body 1a. It is arranged.

The inner blade tip 4a and the outer blade tip 4b are
For example, it is formed in a substantially parallelogrammatic plate shape made of a hard material such as cemented carbide, and both of them are attached toward the tool rotation direction T side with one of the substantially parallelogrammic surfaces as a rake face. The throw-away tip 4 has a main cutting edge 5 that is bent in a substantially dogleg shape on the side edge of the rake face, and two cutting edges 6b and 6c that intersect at an obtuse angle through a step 6a. 6 and 6 are formed in a pair of rotational symmetry to form a substantially parallelogram. The main cutting edge 5 is bent so as to project toward the outside of the throwaway insert 4 having a substantially parallelogram shape. Here, the main cutting edge 5 of the inner blade tip 4a and the cutting edge portion 6 of the outer blade tip 4b are attached so as to project toward the tip side of the tool body 1a so as to serve as the bottom blades of the tool body 1a. , Inner blade tip 4a
The main cutting edge 5 and the cutting edge portion 6 of the outer blade tip 4b are arranged so as to overlap their respective rotation loci. However, the cutting edge portion 6 of the outer blade tip 4b projects further toward the tip side of the tool body 1a than the main cutting edge 5 of the inner blade tip 4a, and is the tip of the tool body 1a.

During drilling of a work material, cutting is carried out by a main cutting edge 5 forming an inner blade and a cutting edge portion 6 forming an outer blade. In particular, the outer blade tip 4b forming an outer blade is cut. Cutting edge 6
Is separated into the two cutting edges 6b and 6c through the step 6a, and the chips generated during the cutting process are generated in a state of being divided by the step 6a. It is designed so that it can be discharged.

[0006]

When drilling with such a throw-away type drilling tool, the chips generated by the rotation of the cutting edge portion 6 of the outer blade tip 4b are the cutting edge portion 6. Since the step 6a is provided in the cutting edge portion 6, the cutting edge portion 6 is divided into shorter portions than the width of the cutting region. However, since there is no action of dividing the chips in the direction in which the chips extend, the chips continue to extend while curling in a spiral shape or the like in sliding contact with the rake face of the outer blade tip 4b. As described above, since the effect of finely cutting chips is insufficient on the outer peripheral side of the tool body 1a where the cutting amount is particularly large, there is a problem that good chip discharging property cannot be obtained.

The present invention has been made in view of the above circumstances, and is a throw-away tip capable of improving the dischargeability of chips by efficiently cutting finely the chips generated during drilling of a work material. Another object of the present invention is to provide a throw-away type drilling tool equipped with the throw-away tip.

[0008]

In order to solve the above problems and to achieve the above object, the throw-away tip of the present invention has an upper surface which is a rake surface and a flank surface of a polygonal flat plate-shaped tip body. In a throw-away tip in which a cutting edge is formed on a ridge portion intersecting with a side surface, the crossing ridge portion includes a first cutting blade and a second cutting blade that intersect each other through a nose portion, each pair being rotationally symmetrical. And the first cutting edge is a circle on at least the nose portion side that intersects at an obtuse angle.
It is composed of an arcuate cutting edge and a linear cutting edge ,
It is characterized in that the arcuate cutting edge portion is formed in an arcuate shape that forms a convex curve curved in the outer direction of the chip body, and the linear cutting edge portion is formed in a straight line shape.

In the throw-away tip having the above construction, the chips produced by the nose side of the first cutting blade are
A U-shaped cross section is formed in the direction in which the chips extend.
Such chips are bent and cut by, for example, slidingly contacting the rake face of the throw-away tip body and being curled. In this way, by effecting the dividing action in the direction in which the chips extend, the chips can be made fine and the chip discharging performance can be improved.

[0010]

In the throw-away tip having the above structure, the chips generated by the first cutting blade are divided and generated at the portions where two adjacent cutting blades intersect each other, so that the width of the cutting area of the first cutting blade is increased. The chips can be divided into smaller pieces, and the chip discharge performance can be further improved.

Further , the throw-away type drilling tool of the present invention is a throw-away type drilling tool equipped with the throw-away tip of the present invention , wherein the tool body is provided on the outer periphery of the drill portion of the tool body having the rotation axis O. Is formed with a pair of chip discharge grooves extending from the front end to the rear end thereof, and the throw-away chip, which is an inner blade chip, is located at a position close to the rotation axis O at the tip of one of the chip discharge grooves, and the other chip discharge groove. The throw-away tip, which is an outer blade tip at a position distant from the rotation axis O at the tip of, is removably mounted on the opposite sides of the rotation axis O, with the cutting edges facing the tip side. Of these, at least the outer blade tip is mounted with the nose portion facing the tip outer peripheral side of the tool body and the first cutting edge facing the tip side of the tool body. It is characterized by a door.

In the throw-away type drilling tool having the above construction, the cutting edge curved in a convex curve is arranged on the outer peripheral side of the tool body in which chip elongation is likely to occur due to a large amount of cutting during cutting. Therefore, the cutting of the chips in the direction in which the chips extend can be effectively acted.

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of a throw-away type drilling tool of the present invention will be described below with reference to FIGS. 1 to 5. FIG. 1 is a plan view showing an embodiment of a throw-away tip according to the present invention, FIG. 2 is a sectional view taken along line ZZ in FIG. 1, and FIG. 3 is a throw-throw equipped with the throw-away tip shown in FIG. It is a side view of an away type drilling tool, and FIG. 4 is a side view which expands and shows the front-end | tip part of the throw away type drilling tool shown in FIG.
FIG. 5 is a front view of the throw-away hole drilling tool shown in FIG. 3 as seen from the front end side. The throw-away tip 10 according to the present embodiment is formed, for example, in a substantially parallelogrammatic plate shape made of cemented carbide, is axially symmetric with respect to the central axis M, and is a flank of the throw-away tip 10. 11 is a positive tip that inclines outward from a lower surface 12 that forms a seating surface toward an upper surface 13 that is a rake surface. A screw hole 14 for inserting a clamp screw that penetrates to the lower surface 12 is provided at the center of the upper surface 13 coaxially with the central axis M. At the ridge line portion where the upper surface 13 and the side surface 11 intersect, the first cutting blade 15 and the second cutting blade 16 both of which are bent in a substantially V shape toward the outside of the throw-away tip 10 are provided with a nose portion 17 therebetween. Are crossed with each other, and each pair is arranged rotationally symmetrically about the central axis M. The nose portion 17 is formed in a substantially convex curved shape protruding toward the outside of the throw-away tip 10.

The first cutting blade 15 has an arcuate cutting edge portion 15a and a linear cutting edge portion 15b on the nose portion 17 side, and a first bending portion 15c.
It is constructed by crossing through. The arcuate cutting edge portion 15a is formed into an arcuate shape, the convex side of which is formed to face the outside of the throw-away tip 10, and the tangent line of the arcuate cutting edge portion 15a in the first bent portion 15c is a straight cutting edge. It intersects the portion 15b at a substantially obtuse angle. The length of the arcuate cutting edge 15a is shorter than that of the linear cutting edge 15b. The arc of the arcuate cutting edge 15a has a larger radius R than the size of the indexable insert 10 main body. The radius R is preferably set to 5.0 to 30.0 mm, and is 15.0 m in this embodiment.
It is supposed to be m. The second cutting edge 16 has two linear cutting edges 1
6a, 16b are configured by intersecting each other at a substantially obtuse angle via the second bent portion 16a, and one linear cutting edge 16a on the nose portion 17 side is formed to be longer than the other linear cutting edge 16b. There is.

The side surface 11 of the throw-away tip 10 is
Intersection with the upper surface 13 and the curved side surface 11A having the arcuate cutting edge portion 15a of the first blade 15 and the flat side surface 11B having the straight cutting edge portion 15b at the ridge line intersecting with the upper surface 13 It is composed of a flat surface 11C on which a linear cutting edge 16a of the second cutting edge 16 is formed and a flat surface 11D on which a linear cutting edge 16b is formed on the ridge portion. Here, the curved side surface 11A is formed in a substantially convex curved surface shape, and the flat side surface 11B.
And the two flat surfaces 11C and 11D are both substantially flat. A tip breaker groove 18 having a substantially arcuate cross section is formed on the upper surface 13 of the throw-away tip 10 along each pair of the first and second cutting edges 15 and 16. As described above, the throw-away tip 10 is formed symmetrically with respect to the central axis M. Therefore, when the throw-away tip 10 is attached to the throw-away type drilling tool or the like, one throw-away tip 10 is changed to a corner. You can use the corner.

The throw-away tip 10 according to the present embodiment has the above-mentioned configuration. Next, the configuration of the throw-away type drilling tool equipped with the above-mentioned throw-away tip 10 will be described. The tool body 20a of the throw-away type drilling tool 20 has a substantially multi-stage cylindrical appearance centered on the rotation axis O, and has a blade portion (drill portion) 21 and a shank portion 22 in order from the front end to the rear end side. And are coaxial with each other about the rotation axis O. A pair of chip discharge grooves 23, 23 are provided on the outer periphery of the blade portion 21 so as to be located on the opposite sides with the rotation axis O interposed therebetween from the front end surface 21A of the throw-away drilling tool 20 toward the rear end side. The chip discharge grooves 23, 23 are formed so as to be twisted at an appropriate angle in a direction opposite to the tool rotation direction T (clockwise in FIG. 5). Of the pair of chip mounting seats 24, 25 provided at the tips of the wall surfaces of the chip discharge grooves 23, 23 facing the tool rotation direction T side, one chip mounting seat 24 is formed at a position away from the rotation axis O. The throw-away tip 10 serving as the outer blade tip 10A is detachably mounted by the clamp screw 26A, and the other tip mounting seat 25 is formed at a position close to the rotation axis O and serves as the inner blade tip 10B. The away tip 10 is detachably attached by the clamp screw 26B.

The outer blade tip 10A is attached such that the first blade 15 of the throw-away tip 10 is directed toward the tip side of the tool body 20a, and the nose portion 17 is projected toward the outer peripheral side of the tool body 20a. The inner blade tip 10B uses the second cutting edge 16 of the throw-away tip 10 as the tool body 20.
The nose portion 17 is attached so as to extend toward the tip end side of a and extend beyond the rotation axis O in the radial direction of the tool body 20a. Here, in both tips 10A and 10B, the respective first bending portion 15a and the second bending portion 16a are projected so that their positions in the direction of the rotation axis O coincide with each other and become the tip of the tool body 20a. There is. Also, the outer blade tip 10
The respective loci of rotation of the first cutting blade 15 of A and the second cutting blade 16 of the inner blade tip 10B intersect and overlap with each other.

Of the pair of tip mounting seats 24, 25, one of the tip mounting seats 24 is seated in a substantially flat surface shape that abuts the flat side surface 11B of the outer blade tip 10A facing the rear end side of the tool body 20a. A wall surface 24B and a seating wall surface 24C having a substantially flat surface shape that contacts the flat surface 11C of the outer blade tip 10A facing the inner peripheral side of the tool body 20a are formed. These seating wall surfaces 24B and 24C intersect toward the rear end side of the tool body 20a via a mounting seat recess 24A formed in a substantially concave curved surface, and the mounting seat recesses 24A are arranged facing each other. The outer blade tip 10A does not come into contact with the curved side surface 11A. Therefore, the outer blade tip 10A
Are fixed by contact between the flat side surface 11B and the seating wall surface 24B in the direction of the rotation axis O and by contact between the flat surface 11C and the seating wall surface 24C in the radial direction of the tool body 20a. There is. On the other tip mounting seat 25, a seating wall surface 25B having a substantially flat surface shape that abuts the flat side surface 11B of the inner blade tip 10B facing the inner peripheral side of the tool body 20a, and an inner surface facing the rear end side of the tool body 20a. A substantially flat seating wall surface 25C that abuts the flat surface 11C of the blade tip 10A is formed, and these seating wall surfaces 25B and 25C are formed in a substantially concave curved surface shape toward the rear end side of the tool body 20a. The mounting seat recesses 25A intersect with each other so that the mounting seat recesses 25A do not come into contact with the flat surfaces 11D of the inner blade tips 10A arranged facing each other. Since the throw-away tip 10 is formed symmetrically with respect to the central axis M, one throw-away tip 10 is used as the outer blade and the inner blade tips 10A and 10B.
Can be used for both.

The throw-away type drilling tool 20 according to the present embodiment has the above-mentioned configuration. Next, the operation when performing the drilling using the throw-away type drilling tool 20 will be described. During drilling of the work material, the tool body 20a is rotated about the rotation axis O, and the outer blade tip 1 protruding toward the tip side of the tool body 20a.
0A first blade 15 and inner cutting tip 10B second cutting blade 16
Is cut by. At this time, the chips are generated by being divided by the first bent portion 15c of the first cutting blade 15 and the second bent portion 16c of the second cutting blade 16.

Moreover, the linear cutting edge portion 15b of the outer blade tip 10A and the two linear cutting edges 16 of the inner blade tip 10B.
The chips generated by a and 16b are slidably brought into contact with the breaker groove 18 of the throw-away tip 10 and curled into a spiral shape, for example. On the other hand, the outer blade tip 10
The chips produced by the arcuate cutting edge portion 15a of A have a U-shaped cross section in the axial direction of the chips, that is, in the direction in which the chips extend. The chips having such a shape are bent and cut by slidingly contacting the breaker groove 18 and being curled. The finely divided chips flow into the twist discharge groove portion on the rear end side of the chip discharge groove 23, and are sent to the rear end side along the twist of the chip discharge groove 23 as the tool body 20a rotates.

As described above, according to the throw-away tip 10 of this embodiment, the first cutting edge and the second cutting edge 15,
The chips can be divided into widths shorter than the respective cutting regions of 16, and the arcuate cutting edge portion 1 of the first cutting blade 15 can be further divided.
The chips generated by 5a have a dividing action even in the direction in which the chips extend, so that the effect of cutting the chips into small pieces is high, and such fine chips can be smoothly discharged. Further, since the side surface 11 of the throw-away tip 10 in which the first cutting edge 15 is formed on the ridge portion is composed of the curved side surface 11A and the flat side surface 11B, a pair of the first away tip 10 of the throw-away tip 10 is provided. Of the blades 15, 15
When installing the first cutting blade 15 as the bottom blade in the throw-away type drilling tool, this first cutting blade 15 and the central axis M
The flat side surface 11B on the side of the other first blade 15 located on the opposite side across the pin can be brought into contact with and fixed to the tip mounting seat of the throw-away type drilling tool.
The throw-away tip 10 can be fixed more reliably than when the 1 A is abutted and fixed.

According to the throw-away type drilling tool 20 of the present embodiment described above, the outer blade tip 10A, which has a large amount of cutting and is likely to grow chips, has the first cutting edge 15 of the throw-away tip 10 and the tip of the tool body 20a. Since it is mounted toward the side, the arcuate cutting edge portion 15a effectively acts, and the chips are finely divided in the direction in which the chips extend, and the chip discharging property is improved. In addition, the cutting amount is 10
The inner cutter tip 10B, which is less in number than A, is mounted with the second cutting edge 16 of the throw-away tip 10 facing the tip side of the tool body 20a, so that one throw-away tip 10 is used as the outer cutter and the inner cutter tip. It can be used for both 10A and 10B, and it is possible to effectively utilize the throw-away tip 10 to extend the life of the throw-away tip 10.

In the present embodiment, the first cutting blade 15 is formed by the arcuate cutting blade portion 15a on the nose portion 17 side and the straight cutting blade portion 15b intersecting each other through the first bent portion 15c. Although configured, it is not limited to this,
More than two cutting edges may be formed to have a polygonal shape. In this case, at least the cutting edge on the nose portion 17 side may be formed in a convex curve shape. Further, the second cutting edge 16 may have the same shape as the first cutting edge 15,
In this case, the throw-away tip 10 is formed in a substantially diamond plate shape.

Further, in the present embodiment, the inner blade tip 10B is the second cutting edge 16 of the throw-away tip 10.
Although the tool is directed to the tip side of the tool body 20a, the invention is not limited to this, and the first blade 15 of the throw-away tip 10 may be directed to the tip side of the tool body 20a. In short, the outer blade tip 10A and the inner blade tip 10B may have their respective loci of rotation intersecting and overlapping with each other.

[0026]

As described in the foregoing, according to the indexable insert of the present invention, chips generated by the nose-side portion of the first change blade, forming section with respect to the direction in which chips extend within U-shaped To be done. Such chips are bent and cut by, for example, slidingly contacting the rake face of the throw-away tip body and being curled. In this way, by effecting the dividing action in the direction in which the chips extend, the chips can be made fine and the chip discharging performance can be improved.

Further , according to the throw-away tip of the present invention, the chips produced by the first cutting blade are divided and produced at the portion where two adjacent cutting blades intersect each other. The chips can be divided into smaller pieces than the width of the cutting region, and the chip discharge performance can be further improved.

Further, according to the throw-away type drilling tool of the present invention, a cutting edge curved in a convex curved shape is formed on the outer peripheral side of the tool body in which chip elongation is likely to occur due to a large amount of cutting particularly during cutting. Since the chips are arranged, the chips can be effectively divided in the chip extending direction, and the chip discharging property can be improved.

[Brief description of drawings]

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

FIG. 2 is a sectional view taken along line ZZ of the throw-away tip shown in FIG.

FIG. 3 is a side view of a throw-away type drilling tool equipped with the throw-away tip shown in FIG. 1.

FIG. 4 is an enlarged side view showing a tip portion of the throw-away type drilling tool shown in FIG.

5 is a front view of the throw-away hole punching tool shown in FIG. 3 as seen from the front end side. FIG.

FIG. 6 is a layout view of a tip end portion of a conventional throw-away tip and a throw-away type drilling tool equipped with the throw-away tip as seen from a side surface side.

7 is a front view of the throw-away type drilling tool shown in FIG. 6 as seen from the front end side.

[Explanation of symbols]

10 Throw-away tip 10A outer blade tip 10B inner blade tip 15 First blade 15a Circular cutting edge 15b Straight cutting edge 15c First bent portion 16 Second cutting edge 16a, 16b Straight cutting edge 16c Second bent portion 17 Nose part 20 Throwaway drilling tools 20a Tool body 21 blade 22 Shank part M central axis

Front Page Continuation (56) References JP-A-53-75589 (JP, A) JP-A-10-71516 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) B23B 27 / 00 B23B 51/00

Claims (2)

(57) [Claims] 1. A throw-away tip in which a cutting edge is formed at an intersection ridge line portion between an upper surface which is a rake face and a side face which is a flank of a polygonal flat plate-shaped chip body, wherein the intersection ridge line portion has a first change blade and a second cutting edge cross each other through the nose portion is arranged in each pair of rotational symmetry, the first change blade, at least the no-crossing substantially obtuse angle
It is constituted by an arcuate cutting edge portion and a linear cutting edge portion on the side of the groove portion, and the arcuate cutting edge portion is formed in an arcuate shape that forms a convex curve curved in the outer direction of the tip body. At the same time, the throw-away tip is characterized in that the linear cutting edge portion is formed in a linear shape. 2. A throw-away type drilling tool equipped with the throw-away tip according to claim 1, wherein the tool body has a rotation axis O on the outer periphery of the drill portion from the tip to the rear end of the tool body. Is formed with a pair of chip discharge grooves extending in parallel, and a throw-away tip that is an inner blade tip at a position close to the rotation axis O at the tip of one of the chip discharge grooves and a rotation away from the rotation axis O at the tip of the other chip discharge groove. The throw-away tips, which are outer blade tips at distant positions, are removably attached to the opposite sides of the rotation axis O with the cutting edges facing toward the tip side. The insert has a throw-away hole in which the nose portion is directed toward the tip outer peripheral side of the tool body and the first cutting blade is mounted toward the tip side of the tool body. Drilling tool.