JPH10180521A - Throw-away tip - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve chip discharge performance. SOLUTION: A device comprises an upper surface of which ridge line comprises a pair of outer blades 14 and a pair of inner blades 18 of which are rotation-symmetric. The outer blade 14 comprises a first cutting blade 15 and a second cutting blade 16 provided through a step 14a, and the inner blade 18 comprises a first cutting blade 19 and a second cutting blade 20 provided through a step 18a. The first cutting blade 15 of the outer blade 14 is protruded outside the second cutting blade 16, and they are formed at different angles from each other. The second cutting blade 20 of the inner blade 18 is protruded outside the first cutting blade 19, and they are formed at different angles from each other. A breaker groove 21 is provided on the inner side of the cutting blades 14, 18.

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 used for a throw-away type drill or the like.

[0002]

2. Description of the Related Art Conventionally, as an example of a throw-away tip used for a throw-away type drill, Japanese Utility Model Application Laid-Open No.
There is one disclosed in JP-A-8992. This throw-away insert will be described with reference to FIGS. 10 and 11. The throw-away type drill 1 includes a shank portion 2 and a blade portion 3, and the outer peripheral surface of the blade portion 3 has a rotation axis O of a drill body 1 a.
A pair of linear or spiral chip discharge grooves (flutes) 4 are formed from the base end portion to the tip end surface along. A throwaway tip 6 is attached to the tip end of each chip discharge groove 4 on the tip end surface 3 a of the blade 3. The throw-away tip 6 is a positive tip having a substantially equilateral triangular plate shape, and a ridge portion between an upper surface 7 and a side surface opposing a lower surface forming a seating surface is a cutting edge 8, and each cutting edge 8 forming three ridges is provided. Has a chevron shape in plan view that protrudes toward the tip end with its central portion 8a as the vertex. When cutting is performed with the indexable insert 6 mounted on the drill 1, chips are generated by the cutting blades 8 of the indexable insert 6, and are discharged through the chip discharge groove 4 to the base end side.

[0003]

When such a throw-away insert 6 is drilled using the drill 1, since the cutting area is the entire cutting edge 8 centered on the vertex 8a, the cutting edge Chips having a width corresponding to the size of 8 will be generated. At that time, it is preferable to bring the cutting start point of each cutting edge 8 as close to the rotation center O of the drill body 1a as possible in order to reduce the cutting torque at the time of biting and prevent the cutting edge from being lost. In addition, to increase the rigidity of the drill 1, it is required to increase the core thickness.
Increasing the core thickness inevitably reduces the cross-sectional area of the chip discharge groove 4 and disadvantageously causes the chips generated by the cutting blade 8 to be easily clogged.

SUMMARY OF THE INVENTION [0004] In view of such circumstances, an object of the present invention is to provide a throw-away insert in which the width of the chip is made smaller with respect to the cutting area of the cutting blade to improve the chip discharge property.

[0005]

A throwaway tip according to the present invention is a throwaway tip in which a ridge formed by an end face and a side face facing a seating surface forms a cutting edge, wherein the cutting edge is at least one of a plurality of steps through a step. It is characterized by being divided into a blade and a second cutting blade. Since the chips are separately cut by the first cutting edge and the second cutting edge at the time of cutting to generate separated chips, the chips are thinned, the chips are less likely to be clogged, and the dischargeability is improved. One of the first cutting edge and the second cutting edge may be formed to protrude outward.

[0006] The first cutting edge and the second cutting edge may have different angles. By cutting at different angles, the running direction of the chips is different, and the separability of the chips is improved. The first cutting edge and the second cutting edge may be arranged at the same angle, that is, in parallel. The cutting blade may have a pair of inner blades and an outer blade facing each other, and the inner blade and the outer blade may be respectively divided into at least a first blade and a second cutting blade via a step. For example, if a tip is mounted on a throw-away drill or the like, the rotation locus can be made continuous by the inner blade and the outer blade. In the throw-away tip, the pair of inner blades and outer blades may be rotationally symmetrical, and the intersection angle between the inner blade and the outer blade may be an obtuse angle and an acute angle facing each other. The cutting blade can be exchanged and used for cutting. A breaker groove may be provided inside the cutting blade.

[0007]

FIG. 1 is a block diagram showing an embodiment of the present invention.
This will be described with reference to FIGS. 1 is a plan view of a throw-away chip according to an embodiment, FIG. 2 is a cross-sectional view taken along line AA of the chip shown in FIG. 1, FIG. 3 is an enlarged view of a breaker groove shown in FIG. 2, and FIG. FIG. 5 is an enlarged view of a cutting edge portion in FIG. 4, FIG. 6 is a front end view of the drill shown in FIG. 4, and FIG. 7 is a view B of the drill shown in FIG. FIG. 8 is a sectional view taken along the line B, FIG.
FIG. 3 is a diagram showing a cutting state by a drill. 1 to 3
, The throw-away tip 10 has a substantially parallelogram plate shape or a substantially octagonal plate shape, and the lower surface 1 forming a seating surface.
1 is an upper surface 12 and a side surface 13 is a lower surface 1
It is a positive chip that is inclined outward from 1 toward the upper surface 12. In the center of the upper surface 12, a hole 9 for screw insertion that penetrates to the lower surface 11 is formed. Note that a clamp surface may be provided instead of the hole 9.

On the upper surface 12, an outer blade 14 forms a ridge line forming a side surface 13 formed from a corner C having a substantially acute corner angle toward one side, and an outer blade 14, and a first blade 15, 15 through a step 14a at the center. The second cutting blade 16 is provided. Moreover, the first cutting edge 15 and the second cutting edge 16 have different angles from each other, and their crossing angle is, for example, 16 °. Also,
The ridge formed by the side surface 13 and the upper surface 12 formed from the corner C to the other side is an inner blade 18 and a step 18 at the center.
The first cutting edge 20 and the second cutting edge 20 are arranged through the line a. Moreover, the first cutting edge 19 and the second cutting edge 20 have different angles from each other (intersection angle is, for example, 5 °), but the difference angle is set smaller than the difference angle of the outer cutter 14.

The outer cutter 14 and the inner cutter 18 are formed in a pair so as to face each other, are respectively formed to be rotationally symmetric, and
The crossing angle of the inner blade 18 is constituted by a pair of acute corners C and a pair of obtuse corners D facing each other. Moreover, the steps 14a and 18a extend from the upper surface 12 to the lower surface 11, respectively. The outer blade 14 and the inner blade 18 are formed to have different lengths from each other, but may have the same length. Further, on the upper surface 12, a breaker groove 21 having, for example, a substantially arc shape in cross section is formed on the inner side of each of the cutting blades 14 and 18 over the entire circumference. A land 22 may be formed on each of the cutting blades 14 and 18 as shown in FIG.

The indexable chip 10 according to the present embodiment has the above-described configuration.
Is used by being attached to a throw-away type drill 40 as shown in FIGS. In the drill 40 shown in FIGS. 4 and 5, the drill body 41 includes a shank portion 42 and a blade portion 43, and a substantially fan-shaped pair is provided at the tip of the drill shown in FIG. Are provided. A pair of chip discharge grooves 45 are formed to face each other with the land portions 44 interposed therebetween. The chip discharge grooves 45 are formed by spirally cutting the outer peripheral surface of the drill body 41 along the rotation axis O. Each chip discharge groove 45 is substantially fan-shaped at the distal end portion of the drill body 41 when viewed from the distal end surface, but has a circular arc-shaped cross section at the proximal end portion near the shank portion 42 as shown in FIG. It is formed so that its cross-sectional shape gradually changes toward the base end side.

Tip mounting seats 46a and 46b are formed at the tip of the wall surface of each chip discharge groove 45 facing the rotation direction.
Is mounted by a clamp member such as a screw. FIG.
In the throw-away type drill 40 shown in FIG. 1, one tip mounting seat 46a is formed on the outer peripheral side with respect to the rotation axis O of the drill body 41, and the outer blade 14 of the attached throw-away tip 10 is attached to the tip of the drill body 11. It is formed so as to protrude to the front end side with respect to the surface. In the chip mounted state, the lead angle of the first blade 15 of the outer blade 14 is set to, for example, 10 °. The other tip mounting seat 46b is formed on the inner side with respect to the rotation axis O of the drill main body 41, and the inner blade 18 of the attached throw-away tip 10 protrudes distally with respect to the distal end of the drill main body 41. It is formed as follows. With the chip mounted,
The inner end of the first blade 19 of the inner blade 18 intersects the rotation axis O, and the lead angle of the second cutting blade 20 is set to, for example, 4 °.

In the tip mounted state, the outer blade 14 projects more toward the tip side in the rotation axis O direction than the inner blade 18, and the angle of each blade with respect to the direction orthogonal to the rotation axis O is as follows.
In a region on one side with respect to the rotation axis O shown in FIG. 8, for example, when indicated by a rotation trajectory, the first cutting edge 16 of the outer blade 14 is 10 ° (lead angle) inward from the outer peripheral side and the second cutting edge 16 is inward. From the outer side to the inner side, the first cutting edge 19 of the inner blade 18 is 9 ° from the outer side to the inner side, and the second cutting edge 20 is also 4 ° from the outer side to the inner side (lead angle). ) Is set to The outer cutter 14 and the inner cutter 18 are assumed to be continuous on the rotation locus. Therefore, at the start of cutting, the outer blade 14 is at the end on the rotation axis O side of the first blade 15,
The inner cutter 18 first comes into contact with the workpiece at the end of the second cutting edge 20 on the rotation axis O side. Also, an oil hole 48 is formed in the center of the drill body 11, and the tip of the oil hole 48 is bifurcated and discharged from the openings 48a and 48b shown in FIG.

When drilling a hole using the throw-away type drill 40 in such a mounted state, first, the first cutting edge 15 of the outer blade 14 comes into contact with the work material to start cutting. The inner end of the first blade 15 provided with the lead angle first comes into contact with the workpiece, so that the impact and cutting torque at the time of biting can be reduced. Then, with a slight delay, the second cutting edge 20 of the inner cutter 18 starts cutting at the inner end thereof, so that the cutting torque at the start of cutting of the inner cutter 18 can be similarly reduced. Moreover, since the outer blade 14 and the inner blade 18 do not start cutting at the same time and the outer blade 14 cuts first, the impact and cutting resistance at the time of biting can be reduced.

Then, the first and second cutting blades 1 of the outer blade 14
By cutting the work material at 5 and 16, the chips generated by the outer blade 14 have a step 14 a as shown in FIG. It will be produced in a state separated from the chips. Moreover, since the angles of the first cutting edge 15 and the second cutting edge 16 are different, chips run in slightly different directions. Similarly, the inner blade 18
Is generated in a state where it is separated into chips by the first blades 19 and chips by the second cutting blades 20 due to the step 18a, and travels in different directions.
Then, the chips are curled in the breaker groove 21 and cut off. Therefore, even if the core thickness of the core thickness portion 39 is set large in order to increase the drill rigidity of the throw-away type drill 40 and the cross-sectional area of the chip discharge groove 45 is reduced, the chip is divided into two parts. By running in the chip discharge groove 45, chip clogging can be suppressed and smooth guided discharge can be performed. Note that the inner blade 18 may protrude more toward the tip side in the rotation axis O direction than the outer blade 14.

As described above, according to the present embodiment, the chips generated by the inner blade 14 and the outer blade 18 are generated in a state of being finely divided into a plurality of pieces. The chip can be discharged. In particular, insert this throw-away tip 10 into a throw-away drill 4
If it is set to 0, the chips can be smoothly discharged through the chip discharge grooves 45 even if the core thickness is increased to increase the rigidity of the drill 40 and the cross-sectional area of the chip discharge grooves 45 is reduced.

Also, in the embodiment, the indexable insert 10 is such that the outer blade 14 has the first all-blade 15 as the inner blade 1.
8, the second cutting edge 20 is arranged to protrude outward, but conversely, the second cutting edge 16 of the outer cutter 14 and the inner cutter 1
The eighth first blade 19 may project outward. In the embodiment, the two cutting edges 15, 16 at different angles via the steps 14a, 18a so that the generated chips are divided into two, respectively, for the outer blade 14 and the inner blade 18. 19 and 20,
Two or more steps may be provided and three or more cutting blades may be used. In this case, chips are generated in a state of being separated into three or more divisions. The angles of the first and second cutting blades of the outer blade 14 and the inner blade 18 may be the same (parallel).

In the indexable insert of the present invention, the "outer blade" and the "inner blade" are simply named for the sake of convenience so as to be distinguished from each other. It goes without saying that the outer cutter 14 may be arranged on the inner side with respect to the rotation axis O, and the inner cutter 18 may be arranged on the outer peripheral side. In addition, the throw away tip 10
The pair of outer blades 14 and the inner blades 18 having different configurations (shapes) are formed.
8 may be formed in the same shape. In the embodiment, the cutting blade is provided only on the upper surface 12 of the chip 10, but the cutting blade may be provided on both upper and lower surfaces.

[0018]

As described above, in the indexable insert according to the present invention, since the cutting edge is divided into at least the first cutting edge and the second cutting edge via the step, the first cutting edge and the second cutting edge are cut at the time of cutting. Since the chips separated by the two cutting blades are generated, the chips become thinner, the chips are less likely to be clogged, and the dischargeability is improved.

Further, since the first cutting edge and the second cutting edge have different angles, cutting at different angles results in different running directions of the chips, thereby improving the separation of the chips. Further, since the cutting blade has a pair of inner and outer blades facing each other, and the inner and outer blades are separated into at least a first blade and a second cutting blade via a step, respectively, for example, If inserts are attached to a throw-away type drill, etc., one insert can perform the functions of two types of cutting blades, leading to cost reduction, and the inner blade and outer blade can make the rotation locus continuous, and the cutting blade can be replaced. It can be used for cutting.

[Brief description of the drawings]

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

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

FIG. 3 is an enlarged view of the breaker groove of FIG. 2;

FIG. 4 is an overall view of a throw-away drill to which a throw-away tip according to an embodiment is attached.

FIG. 5 is an enlarged view of a cutting edge portion of the drill in FIG.

FIG. 6 is a front end view of the drill shown in FIG. 4;

7 is a sectional view of the drill shown in FIG. 4 taken along line BB.

FIG. 8 is a diagram showing a contour of a tip of a cutting blade of a drill.

FIG. 9 is a diagram showing a cutting state by a drill.

FIG. 10 is a side view of a conventional drill.

11 is a front end view of the drill shown in FIG.

[Explanation of symbols]

 10 indexable insert 14 outer blade 14a, 18a step 15, 19 first blade 16, 20 second cutting blade 18 inner blade

Continued on the front page (72) Inventor Yasuhiko Kawade Gibe, Kochi-cho, Anpachi-gun, Gifu Prefecture 1528 Nakashinden, Yokoi, Mitsubishi Materials Corporation Gifu Works

Claims (5)

[Claims] 1. A throw-away insert in which a ridge formed by an end surface and a side surface facing a seating surface forms a cutting edge, wherein the cutting edge is divided into at least a first cutting edge and a second cutting edge via a step. A throwaway tip characterized by: 2. The indexable insert according to claim 1, wherein the first cutting edge and the second cutting edge have different angles. 3. The cutting blade has a pair of inner blades and an outer blade facing each other, and the inner blade and the outer blade are respectively connected to at least the first blade and the second cutting blade via the step. 3. The indexable insert according to claim 1, wherein the insert is divided. 4. The indexable insert according to claim 1, wherein the pair of inner blades and the outer blades are each rotationally symmetric, and an intersection angle between the inner blade and the outer blades is a pair of obtuse angles and a pair of acute angles facing each other. The throw-away tip according to claim 3, characterized in that: 5. The indexable insert according to claim 1, wherein a breaker groove is provided inside the cutting blade.