JPH10235511A - Throw away tip - Google Patents

Abstract

PROBLEM TO BE SOLVED: To perform boring of a plurality of kinds of diameters by using differ ent tool main bodies by forming a difference in level on the way of a main cutting edge, making the tip part of the main cutting edge a projecting curved shape which gradually approaches the bottom and making the rear end part a corner. SOLUTION: A main cutting edge 6 is separated into a first cutting edge part 6a and a second cutting edge part 6b by a difference in level 7. Because the rear end part 6d on the outer peripheral side of the main cutting edge 6 is made a nose even if the fitting angle of a throw away tip 1 is changed, fracturing of the cutting edge 6 can be suppressed. By using various kinds of drills provided with tip fitting seats which are different in angles of the first side walls by using the same throw away tip 1, plural kinds of throw-away tipped drills having main cutting edges 6 which are different in tip angles and different in outside dimensions.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a throw-away insert which can be mounted on a throw-away type drill used for drilling or the like.

[0002]

2. Description of the Related Art
When drilling is performed using a two-flute indexable drill, rotary cutting is performed with the main cutting edge of two indexable inserts attached to the tip of the drill body. By the way, when the hole is drilled with such a throw-away type drill, if the inner diameter of the hole is different, another insert with a main cutting edge having an outer diameter dimension corresponding to the inner diameter is attached to the insert. It had to be mounted on another drill body equipped with a possible chip mounting seat for cutting. Therefore, it is necessary to separately prepare a corresponding throw-away tip and a drill body for mounting the same in accordance with the hole size to be machined, resulting in high cost, and a chip having a desired size at the time of hole machining and conforming thereto. There is a disadvantage that the selection of the drill body is complicated.

[0003] In view of the above problems, an object of the present invention is to provide a throw-away insert that can be used for different tool bodies and can be used to machine a plurality of types of holes.

[0004]

The indexable insert according to the present invention has a lower surface forming a seating surface and an upper surface forming a rake face opposite to the lower surface, and is inclined outward from the lower surface toward the upper surface. In the throwaway tip where the intersection ridge line between the side surface and the upper surface is the main cutting edge, the main cutting edge has a step formed in the middle, and the tip of the main cutting edge has a convex curve gradually approaching the lower surface. And the rear end is a corner R. When this tip is mounted on a throw-away type drill, etc., the tip of the main cutting edge has a convex curve shape, so the blade edge strength is large and it is suppressed that the tip is broken at the time of biting etc. And the rear end has a corner R, so that the chip is not easily broken regardless of the mounting angle of the chip. Also, by providing a plurality of types of tool bodies having different angles with respect to the rotation axis of the tip mounting seat, the same throw-away tip can be mounted at different angles with respect to the rotation axis, and the angle of the main cutting edge with respect to the rotation axis is different. This makes it possible to increase or decrease the outer diameter of the tool cutting blade, which is economical. Moreover, since the main cutting edge is provided with a step, the chips are generated in a state of being finely divided into a plurality of pieces.

The main cutting edge may have one or more steps, and the main cutting edges separated by the steps may be parallel to each other. Further, a side clearance angle may be set so that the outer side surface following the rear end of the main cutting edge does not come into contact with the processing surface regardless of the attachment angle of the throw-away insert. For this reason, even if the indexable insert is attached to the tip mounting seats of different tool bodies so that the main cutting edge forms a different angle, the outer side surface does not rub the machined surface during rotary cutting. Further, a breaker groove may be provided on the upper surface along the main cutting edge. Further, the throw-away insert may be formed in a substantially triangular plate shape, and two side surfaces opposite to the side surface forming the flank of the main cutting edge may be positioned in contact with the side wall of the chip mounting seat of the tool body. .

[0006]

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 tip according to an embodiment, FIG. 2 is a side view of the throw-away tip shown in FIG. 1 as viewed in the direction of arrow A, and FIG. 3 is a cross-sectional view of the tip shown in FIG. 4 is an overall view of a throw-away drill equipped with a throw-away tip according to the embodiment, FIG. 5 is a front end view of the drill shown in FIG. 4, and FIG.
5 is an enlarged view of a blade portion of the drill in FIG. 1 to 3, a throw-away tip 1 according to an embodiment is shown.
Is formed in a polygonal plate shape, for example, a substantially triangular plate shape (or a substantially hexagonal plate shape). This throwaway tip 1
The upper surface 3 is provided with a rake face opposite to the lower surface 2 which is a seating surface, and a hole 4 for screw insertion is formed through the lower surface 2 from the center of the upper surface 3. A side surface 5 is formed between the upper surface 3 and the lower surface 2.

The chip 1 has a main cutting edge 6 at the intersection ridge formed by the upper surface 3 and the main side surface 5a forming a flank. At the center of the main cutting edge 6, a step 7 reaching the lower surface 2 is formed. The step 7 causes the main cutting edge 6 to have a first cutting edge portion 6a and a second cutting edge portion 6a.
b. The first cutting edge 6a is the second cutting edge 6.
b, and protrudes outside the second cutting edge 6b. The intersection (side) of the adjacent side surface 5b, which intersects the main side surface 5a at an acute angle, with the upper surface 1 is cut into a convex curved surface and is formed as a convex curved surface 8 that curves from the upper surface 3 to the lower surface 2 so as to approach.
One end of the main cutting blade 6 is curved in a convex curve with a radius Ra as shown in FIG. The other end of the main cutting edge 6 is a rear end 6d which is a nose R in plan view. Further, since the main side surface 5a is inclined outward from the lower surface toward the upper surface 3, the chip 1 is a positive chip using one corner.

The first side face 5c which obliquely cuts the convex curved face 8 adjacent to the side face 5b and the second side face 5d via the chamfered side face 5e have a predetermined intersection angle, and the first and fifth side faces are formed. The two side surfaces 5c and 5d are planes orthogonal to the upper and lower surfaces 3 and 2. A third side surface 5f (outside side surface) having a side clearance angle γ is formed between the main side surface 5a and the second side surface 5d. The side surface 5b and the third side surface 5f are also inclined outward from the lower surface 2 toward the upper surface 3 similarly to the main side surface 5a. On the upper surface 3, a breaker groove 9 having an arc-shaped cross section as shown in FIG. 3 is formed along the main cutting edge 6. The breaker groove 9 is formed stepwise along the step 7 and the first and second cutting edge portions 6a and 6b, and ends at the leading end 6c side of the main cutting edge 6 by intersecting the convex curved surface 8 and ending. The end 6d is connected to the third side surface 5f.

The indexable insert 1 according to the present embodiment has the above-described configuration. Next, an indexable drill 10 to which the insert 1 is mounted will be described with reference to FIGS. 4 to 6, the drill body 11 of the throw-away drill 10 includes a shank portion 12.
The tip surface 13a of the blade portion 13 of the drill body 11 is formed in a substantially conical tapered surface having an apex at the intersection with the rotation axis O, and the vicinity of the apex falls to the base end side. The recess 14 is provided. A pair of chip discharge grooves 15 having a substantially fan-shaped cross section are formed on the outer peripheral surface of the blade portion 13 so as to face the rotation axis O (see FIG. 5).
5 is formed by spirally cutting the outer peripheral surface along the rotation axis O.

[0010] Wall surface 1 of each chip discharge groove 15 facing the rotation direction
5a is a chip mounting seat 17 whose tip is cut out in a substantially V shape in plan view, and the chip mounting seat 17 has a bottom surface 17a.
And first and second side walls 17b and 17c on both sides thereof, and a slack is formed at the intersection of the first and second side walls 17b and 17c. The intersection angle between the first and second side walls 17b and 17c is different from the first and second side surfaces 5 of the throw-away tip 1.
It is set to be the same as the intersection angle between c and 5d. As shown in FIG. 5, the first side wall 17b on the side close to the rotation axis O of the drill body 11 has a larger angle (angle) with the rotation axis O than the wall surface 15b of the chip discharge groove 15 facing rearward in the rotation direction. α), and protrudes outward. Also, the first side wall 17
The angle α of b is determined according to the tip angle β of the main cutting edge 6 of the drill 10, that is, the outer diameter dimension φD of the main cutting edge 6, as described later.

As shown in FIG. 6, two indexable inserts 1 according to the embodiment are mounted on the respective tip mounting seats 17 of the drill body 11, and the first and second side surfaces 5c, 5d of the respective inserts 1 are provided. Are brought into contact with the first and second side walls 17b and 17c of the chip mounting seat 17. At this time, the convex curved surface 8 of the tip 1 protrudes from the tip mounting seat 17 to the distal end side, is located near the rotation axis O and almost parallel to the outside thereof, and the main cutting edge 6 is defined by a line perpendicular to the rotation axis O. It is screwed in an attached state forming an acute angle θ (for example, θ ₁ ). Therefore, the main cutting edges 6, 6 of the pair of indexable inserts ₁ , ₁ are provided with a tip angle β (for example, β ₁ ) via a concave portion 14 (chisel portion) that is concave toward the base end in the region of the rotation axis O.
β ₁ = 180 ° −2θ ₁ ). A pair of main cutting blades 6
Is set in advance, the outer diameter φ of the main cutting edge 6 of the drill 10 depends on the angle θ of the main cutting edge 6, ie, the tip angle β.
D (eg, D ₁₎ are determined. In addition, a step 18 is also formed on the tip end surface 13a of the blade portion 13 from the intersection ridge line with the bottom surface 17a of the tip mounting seat 17 in accordance with the step 7 of the main cutting blade 6.

The indexable drill 10 equipped with the indexable insert 1 according to the present embodiment is configured as described above. At the time of cutting, a pair of main cutting edges 6 and 6 having a tip angle β ₁ is used. Drilling is performed. At this time, thin chips are separately generated at the first cutting edge portion 6a and the second cutting edge portion 6b of the main cutting edge 6, and flow smoothly along the chip discharge groove 15 to be discharged from the base end side. . At the time of cutting, the speed around the rotation axis O of the drill body 11 becomes low, but since the concave portion 14 is provided and the main cutting edge 6 is not provided, there is no breakage. Since no chisel is provided in this portion, thrust resistance during cutting is small. For this reason, uncut portions can be left in the concave portions 14 at the time of drilling cutting. However, since the uncut portions are broken by the generated chips or crushed by the drill 10, no problem occurs.
Further, the workpiece gradually comes into contact with the main cutting edge 6 from the front end side. However, since the front end portion 6c of the main cutting edge 6 has a convex curve, the main cutting edge 6 has an impact on the main cutting edge 6 when biting. The load is not applied, and the tip 6c is not easily chipped. Further, since the first side wall 17b on the rotation axis O side of the tip mounting seat 17 receiving the cutting load of the throw-away tip 1 projects outward from the wall surface 15b of the chip discharge groove 15 facing rearward in the rotation direction, the drill rigidity is reduced. high. Since the rear end portion 6d on the outer peripheral side of the main cutting edge 6 has a nose R, it is possible to suppress breakage during cutting.

When the outer diameter φD of the main cutting edge of the drill 10 is to be made larger and a larger diameter hole is to be drilled, as shown in FIG. A drill 20 of the same size is used. The tip mounting seat 17 '
The angle α (eg, α ₂ ) of the first side wall 17 b ′ with respect to the rotation axis O is set to be larger than α ₁ , and the intersection angle between the first and second side walls 17 b ′ and 17 c ′ is set to be the same as that of the drill 10. I just need. When the above-described throw-away tip 1 is mounted on the drill 20, the angle θ (for example, θ ₂ ) of the main cutting edge 6 with respect to a line orthogonal to the rotation axis O becomes larger than θ ₁ , and a pair of throw-aways Chip 1,
The tip angle β (for example, β ₂ ) of the _first main cutting edge 6 becomes larger than the angle β ₁ , and the outer diameter φ of the main cutting edge 6 of the drill 20.
D (for example, D ₂₎ also increases from D ₁ by a predetermined distance.

Even if the mounting angle of the throw-away tip 1 changes, the rear end 6d of the outer peripheral side of the main cutting edge 6 has a nose R, so that it is possible to suppress breakage during rotary cutting. A third side surface 5 connected to the rear end 6d of the chip 1
f, a positive side clearance angle γ (with respect to a line parallel to the rotation axis O) is set so as not to scratch the processing surface with respect to the maximum value of the mounting angle θ that the main cutting edge 6 can take. Therefore, there is no possibility that the third side surface 5f of the chip 1 will scrape the machined surface during rotary cutting. Therefore, various drills 10 having the tip mounting seats 17, 17 'having different angles α of the first side walls 17b, 17b'.
20 ..., the tip angle β differs, and the outer diameter dimension φ
A plurality of types of indexable drills having main cutting edges 6 having different D can be obtained. An example of the correlation between the angle θ of the main cutting edge 6 with respect to a line orthogonal to the rotation axis O, the tip angle β of the main cutting edge 6 and the outer diameter φD is shown in Table 1 below. become.

[0015]

[Table 1]

As described above, according to the present embodiment, 1
Each of the tip mounting seats 17, 17 'having a different angle .alpha.
Can be mounted on a plurality of types of drills 10, 20,... Provided with the above, and a plurality of types of indexable drills having different outer diameters φD of the main cutting edge 6 can be obtained. Accordingly, the same tip is mounted on different drills 10, 20,... To obtain drills having different outer diameters, and it is possible to perform a drilling operation with different inner diameters, and it is economical because it is not necessary to provide a plurality of types of tips. In addition, the work of attaching the tip 1 to various drills becomes easy.

FIGS. 8 to 10 show a second embodiment of the present invention.
Has a substantially triangular plate shape having a configuration substantially similar to that of the above-described indexable chip 1, and the same reference numerals are given to the same portions as the chip 1. In the tip 30, an intersection ridge formed by the upper surface 3 and the main side surface 5a is a main cutting edge 31,
Two steps 32, 33 are formed in the middle of the main cutting blade 31, and the separated first all-blade portion 31a, the second cutting blade portion 31b,
The third cutting edge portion 31c is formed in parallel with each other. The steps 32 and 33 extend from the main cutting edge 31 to the lower surface 2 and are provided in steps on the main side surface 5a. The leading end 31d of the main cutting edge 31 has a convex curve shape gradually approaching the lower surface 2, and the rear end 31e has a nose R. The cutting edge 41 of the drill 40 equipped with the indexable insert 30 is shown in FIG.
Is shown in In FIG. 11, the tip surface 4 of the blade portion 41
1a, a stepped portion 4 corresponding to the steps 32, 33 of the main cutting edge 31 from the intersection ridge line with the bottom surface 42a of the chip mounting seat 42.
3, 44 are provided.

Therefore, the generated chips are divided into three. The number of steps formed on the main cutting edges 6 and 31 may be three or more, and the cutting blades are divided and formed according to the number of steps, and chips are generated according to the number of cutting blades. Each cutting edge may not be parallel to each other. Further, the shape of the chips 1 and 30 is not limited to a substantially triangular shape, and various shapes such as a square plate shape can be adopted.

[0019]

As described above, in the indexable insert according to the present invention, the main cutting edge has a step formed in the middle thereof, and the tip of the main cutting edge has a convex curve shape gradually approaching the lower surface. Since the rear end is a corner R, when this tip is mounted on a throw-away type drill or the like and cut, cutting chips are generated in a state of being finely divided into a plurality according to the number of steps, Good chip evacuation. In addition, since the tip of the main cutting edge has a convex curve shape, the tip strength is large, and it is possible to prevent the tip from being damaged at the time of biting, etc.
Further, since the rear end portion has a corner R, the chip is unlikely to be broken regardless of the mounting angle of the chip. Also, by providing a plurality of types of tool bodies having different angles with respect to the rotation axis of the tip mounting seat, the same throw-away tip can be mounted at different angles with respect to the rotation axis, and the angle of the main cutting edge with respect to the rotation axis is different. This makes it possible to increase or decrease the outer diameter of the main cutting edge, which is economical. The outer side surface following the rear end of the main cutting edge has a side clearance angle set so that it does not come into contact with the processing surface regardless of the mounting angle of the indexable insert. Even if the indexable insert is mounted so that the cutting edges have different tip angles, the outer side surface does not rub against the processing surface during rotary cutting.

[Brief description of the drawings]

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

FIG. 2 is a side view of the throw away tip shown in FIG.

FIG. 3 is a sectional view taken along line BB of the throw-away tip shown in FIG.

FIG. 4 is an overall view of a throw-away drill equipped with a throw-away tip according to the first embodiment.

FIG. 5 is a front end view of the drill shown in FIG. 4;

FIG. 6 is an enlarged view of a blade portion of the drill in FIG.

FIG. 7 is an enlarged view of the blade portion in a state where the indexable insert is mounted on a drill having a tip mounting seat at another angle.

FIG. 8 is a plan view of a throw-away tip according to a second embodiment of the present invention.

FIG. 9 is a side view of the throw away tip shown in FIG.

FIG. 10 is a DD of the throw-away tip shown in FIG. 8;
It is a line sectional view.

FIG. 11 is an enlarged view of a blade portion of a throw-away drill equipped with a throw-away tip according to the second embodiment.

[Explanation of symbols]

 1, 30 indexable insert 5a main side 5c first side 5d second side 5f third side 6,31 main cutting edge 6a, 31a first cutting edge 6b, 31b second cutting edge 6c, 31d tip 6d, 31e Rear end 17, 17 'Chip mounting seat 17b, 17b' First side wall 17c, 17c 'Second side wall 31c Third cutting edge

Claims (2)

[Claims] 1. A lower surface forming a seating surface, and an upper surface forming a rake face opposing the lower surface, wherein an intersection ridge line portion of the side surface inclined outward from the lower surface side to the upper surface and the upper surface is mainly provided. In the indexable insert that is a cutting edge, the main cutting edge has a step formed in the middle thereof, and the front end portion of the main cutting edge has a convex curve shape gradually approaching the lower surface, and the rear end portion has a corner R. A throwaway tip characterized by being done. 2. An outer side surface following a rear end of the main cutting blade,
2. The throw-away insert according to claim 1, wherein a side clearance angle is set so that the side-away insert does not come into contact with a processing surface regardless of an attachment angle of the throw-away insert.