JPH09131621A - Manufacture of throw-away tip for drilling, and throw-away tip for drilling - Google Patents

Abstract

PROBLEM TO BE SOLVED: To easily form a screw flitting hole with a countersunk part in each cutting face by providing a projected part for forming a countersunk part in which a pin insertion hole for forming a screw fitting hole is provided and a tip part is shrunk in a tapered manner. SOLUTION: The size and the shape inside a pair of dies 20a, 20b are formed so as to be compounding to a throw-away tip 10 for drilling. Pins 21a, 21b for forming a hole in the dies 20a, 20b are arranged so as to be corresponding to each screw fitting hole 14 formed in each of cutting faces 12a, 12b of the throw-away tip 10 for drilling. Projected parts 23b, 23a for forming a countersunk part are provided where insertion holes 22b, 22a in which pins 21a, 21b are inserted are provided on other dies 20b, 20a so as to be corresponding to the pins 21a, 21b, and the tip part is shrunk in a tapered manner.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a drill that cuts an object to be drilled to make a hole, and has a throw-away type drill having a drill throw-away tip attached to the tip of the drill body, and a drill body. The present invention relates to a throw-away tip for a drill that is attached to the tip end of a and a method for manufacturing the throw-away tip for a drill.

[0002]

2. Description of the Related Art Conventionally, various drills have been used for making holes by cutting an object to be cut such as metal.

Conventionally, as such a drill, a drill having a cutting edge formed on both sides of its rotation center made of cemented carbide or the like and brazed to the tip of the drill for cutting is generally used. Was there.

Here, when the object to be cut is cut and a hole is drilled in the drill having the tip portion brazed with cemented carbide, the cutting edge portion at the tip portion is gradually worn away and the cutting property is improved. Therefore, the part of the cutting edge worn as described above is reground and used.

However, it takes skill to regrind the worn cutting edge portion well, and the work is very troublesome, difficult and time-consuming, and the cutting edge portion is regrinded many times. Then, the length of the drill is changed, and there is a problem that various setting conditions and the like in the drilling device to which the drill is attached have to be changed.

For this reason, in recent years, a throw-away tip provided with a cutting edge at the tip of a drill body is attached with a screw, and when the cutting edge of the throw-away tip is worn by cutting, this throw-away tip is used. A throw-away type drill was developed that was designed to be replaced.

As a throw-away type drill in which the throw-away tip is attached to the tip of the drill body in this way, one throw-away tip is attached to each side of the center of rotation at the tip of the drill body. Alternatively, there was one in which a single throw-away tip provided with cutting edges on both sides of the center of rotation was attached to the tip of the drill body.

[0008] Here, in the case of a throw-away type drill in which one throw-away tip is attached to each of the two sides of the center of rotation at the tip of the drill body,
It is necessary to prepare two types of throw-away tips, and also two throw-away tips must be attached to the tip of the drill body, which increases the number of parts and costs, and also replaces the throw-away tip. There was a problem such as troublesome work.

In the case of a throw-away type drill in which cutting inserts having cutting edges on both sides of the center of rotation are attached to the tip of the drill body, the throw-away tip is firmly attached to the tip of the drill body. Therefore, a tip attachment part for attaching the throw-away tip is provided at the tip of the drill body, and screw holes are provided on each attachment surface of this tip attachment part on both sides of the rotation center,
Corresponding to the screw holes on each mounting surface, the countersunk screw with countersink so that the countersink of the countersunk screw does not protrude to the rake face of each cutting edge provided on both sides of the rotation center in the throw-away tip. It was designed to have mounting holes.

Then, the screw mounting holes with countersink holes provided on each rake face of the throw-away tip are aligned with the screw holes provided on each mounting face of the drill body, and in this state, the screws with countersink are used. The throw-away tip was attached to the tip of the drill body.

However, it is extremely difficult to form a screw mounting hole with a countersink portion on each rake face of the throw-away tip so as to correspond to the screw hole provided on each mounting face of the drill body as described above. It was very difficult.

Therefore, when manufacturing the throw-away tip for a drill as described above, the material for the throw-away tip is filled in a mold, and this is pressed in the mold, and at 600-1000 ° C. Corresponds to the position to form a screw hole with a countersink for this chip temporary sinter after it is made into a soft state that is easy to process by temporary sintering at a temperature After performing the hole processing and forming to a certain shape, the processed product is again sintered at 1350 to 1550 ° C., and then the sintered product is subjected to finish processing such as grinding and the like as described above. It was considered to manufacture throwaway inserts for various drills.

However, when the throw-away tip is manufactured as described above, the manufacture of the throw-away tip is very troublesome and difficult, the cost is high, and the screw mounting hole with the countersink portion is formed. There was a problem that the position of the screw mounting hole with countersink part on each rake face of the throw-away tip was displaced when the hole was drilled to correspond to the position .

Further, in the conventional throw away type drill as described above, the chip guiding groove in the drill body is linear, and the rake face of the throw away tip attached to the drill body is raked. There was also a problem that the angle was 0 °, and the machinability as a drill and the chip discharge performance were poor.

[0015]

SUMMARY OF THE INVENTION According to the present invention, as described above, a throw-away tip having cutting edges and a rake face on both sides of the center of rotation is attached to the tip of a drill body with a countersunk screw. It is an object of the present invention to solve the various problems described above.

That is, according to the present invention, as described above, screw holes are provided on each mounting surface of the tip mounting portion provided at the tip of the drill body, and the screw holes are made to correspond to the screw holes on each mounting surface. Screw holes with countersink holes are provided on the rake face of each cutting edge on both sides of the throw-away tip, and screw holes with countersink holes are provided on each rake face of the throw-away tip. In throw-away drills, in which the throw-away tip is firmly attached to the tip of the drill body by using screws to match the screw holes provided on each mounting surface of the drill body, the screws on each mounting surface of the drill body It is easy to accurately provide a screw mounting hole with a countersink on each rake face of the throw-away tip so as to correspond to the hole. The manufacturing of Eichippu is the so performed in a simple and low cost, it is an object to improve the dischargeability of machinability and chip in such indexable drills.

[0017]

In the method of manufacturing a throw-away tip for a drill according to the present invention, in order to solve the above problems, the cutting edges 11a and 11b and the rake faces 12a and 12b are located on both sides of the rotation center. In order to manufacture the throw-away tip for drill 10 in which the screw mounting hole 14 with the countersink portion 14a is formed in each rake face 12a, 12b, a pair of molds 20a, 2
0b, a pair of holes forming pins 21a, 21b corresponding to the screw mounting holes 14 in the rake faces 12a, 12b.
And the pins 21a, 2 are respectively attached to the molds 20b, 20a so as to correspond to the pins 21a, 21b.
1b is provided with insertion holes 22b and 22a, and the distal end portion is tapered and contracted to form a countersink-shaped protruding portion 23.
b, 23a is provided, and the pair of molds 20a, 20b is provided.
A material for the throw-away tip is filled in the space between the pins 21a, 21b, and the corresponding projections 23b, 2
The inserts 22a and 22a of 3a are inserted into the inserts to compress the throw-away tip material, which is then sintered and finish-processed to manufacture the throw-away tip 10 for a drill.

When the throw-away tip 10 for a drill is manufactured in this manner, the material for the throw-away tip is pre-sintered as in the conventional case to prepare a pre-sintered insert for the tip in a soft state which is easy to process. After that, it is not necessary to perform a troublesome work such as forming the provisional sintered product for a chip to provide a hole corresponding to a screw mounting hole with a countersink portion, and at the same time, screw with a countersink portion 14a. Mounting hole 14
The holes for forming the holes can always be accurately provided at fixed positions, and the accurate throw-away tip for a drill can be easily manufactured.

Here, as described above, the pair of molds 20a,
The pair of pins 21a and 21b provided on the mold 20b are connected to the protrusions 23b and 23 provided on the molds 20b and 20a, respectively.
When inserting into the insertion holes 22b and 22a of a, the respective pins 21a and 21b are not properly inserted into the insertion holes 22b and 22a, and the insertion holes 22 in the protrusions 23b and 23a are inserted.
The protrusions 23b, 23
Since a may be damaged, this protrusion 23
It is preferable to increase the angle of the tapered portion at the tips of b and 23a and to provide a flat portion around the insertion holes 22b and 22a to increase the strength of the protrusions 23b and 23a.

Further, in the throw-away tip for a drill of the present invention, the cutting edges 11a and 11b and the rake face 1 are provided.
2a and 12b are provided on both sides of the center of rotation,
Throw-away tip 1 for drill in which screw mounting holes 14 with countersink portions 14a are formed on each rake face 12a, 12b
0, the countersink part 14 in the screw mounting hole 14 with countersink part 14a provided in each of the above-mentioned rake faces 12a, 12b
The angle θ of the tapered portion of a is set to 70 ° or more.

Then, like the throw-away tip for a drill according to the present invention, the angle of the tapered portion of the countersink hole 14a in the screw mounting hole 14 with the countersink hole 14a provided on each rake face 12a, 12b is 70 ° or more. With this configuration, when manufacturing the throw-away tip 10 for a drill as described above, it is possible to increase the angle of the taper portion at the tip end portions of the protrusions 23b and 23a. Provided pins 21a, 2
When inserting 1b into the insertion holes 22b, 22a of the corresponding protrusions 23b, 23a of the other mold 20b, 20a, the pins 21a, 21b are inserted into the insertion holes 22b, 2a.
Even if the projections 23b, 23a are not properly inserted into the 2a and come into contact with the edges of the insertion holes 22b, 22a in the projections 23b, 23a, the projections 23b, 23a are less likely to be damaged. Stable manufacturing becomes possible.

In order to prevent the protrusions 23b and 23a from being damaged in this way, it is possible to increase the angle θ of the tapered portion of the countersink 14a in the screw mounting hole 14 with the countersink 14a. Although it is preferable, if the angle θ is too large, the pressing force when the drill throw-away tip 10 is attached to the drill body 30 by screwing the screw 13 with the dish 13a into the screw mounting hole 14 with the countersink portion 14a becomes weak. Therefore, the angle θ of the tapered portion of the countersink portion 14a is preferably set to 80 to 100 °.

Further, in the throw-away type drill according to the present invention, at the tip portion of the drill body 30,
A tip mounting portion 31 for mounting the above-mentioned drill throw-away tip 10 is provided from the center of rotation toward both sides, and each of the above-mentioned drill throw-away tips 10 is provided on both side mounting surfaces 32 of this tip mounting portion 31. Screw holes 33 corresponding to the screw mounting holes 14 with countersink portions 14a on the rake faces 12a and 12b are provided, and the above-mentioned drill throw-away tip 10 is mounted on the drill body 30.
Mounted on the tip mounting part 31 at the tip of the drill, and the screw mounting holes 14 with the countersink parts 14a provided on the rake faces 12a and 12b of the drill throw-away tip 10 and the mounting faces on the chip mounting part 31. Three
The screw holes 33 provided in 2 are aligned with each other, and the drill throw-away tip 10 is detachably attached to the tip portion of the drill body 30 by the screw 13 with the plate 13a.

Then, like the throw-away type drill of the present invention, the drill throw-away tip 10 is attached to the tip mounting portion 31 provided at the tip of the drill body 30, and each scoop in the drill throw-away tip 10 is made. Countersink holes 14 provided on the surfaces 12a and 12b
Align the screw mounting hole 14 with a with the screw hole 33 provided in each mounting surface 32 of the tip mounting portion 31, and use the screw 13 with the plate 13a to move the drill throw-away tip 10 to the tip of the drill body 30. When attached, the above-mentioned drill throw-away tip 10 is used for the drill body 30.
It can be easily and surely attached to the tip end of the plate by the two screws 13 with the plate 13a.

Further, in the throw-away type drill of the present invention, the drill body 30 is provided with the chip guiding spiral groove 3.
4 and the above-mentioned drill throw-away tip 10 attached to the tip of the drill body 30.
Rake angle of each rake face 12a, 12b at +10
When it is set to be equal to or more than 0 °, the dischargeability of chips in this throw-away drill is improved and the cutting property is also improved. Then, from the viewpoint of improving the chip discharge performance in this throw-away drill, the twist angle in the above-described twist groove 34 is 10 ° or more, preferably 17 to.
It is preferable that the rake angle of each rake face 12a, 12b of the throw-away tip 10 for drill is +17 to 25 ° from the viewpoint of improving the machinability of the throw-away drill by setting the angle to 25 °.

[0026]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be specifically described below with reference to the accompanying drawings.

Here, in the throw-away tip 10 for a drill of this embodiment, as shown in FIGS. 1A to 1C, the cutting edges 11a and 11b and the cutting edges 11a and 11b are provided on both sides of the center of rotation. Rake face 12a, 12b against
And each of the rake faces 12a, 12b is provided with a screw mounting hole 14 having a countersink hole portion 14a for accommodating the countersink portion 13a of the countersunk screw 13 respectively.
The angle θ of the tapered portion of the countersunk hole 14a of No. 4 is about 9
It was set to 0 °.

Here, in manufacturing such a throw-away tip 10 for a drill, in this embodiment, as shown in FIG. 2, the size and shape of the pair of molds 20a, 20b in the mold are as described above. The rake faces 12a, 12b of the throw-away tip 10 for drill are formed corresponding to the throw-away tip 10 for drill.
In order to correspond to the screw mounting holes 14 formed in the mold, holes 21a, 21b for forming holes are formed in the molds 20a, 20b, respectively.
21b is arranged, and each pin 21a, 21b is made to correspond to the other mold 20b, 20a and each pin 2
Insertion holes 22b and 22a for inserting 1a and 21b are provided, and projecting portions 23b and 23a for forming countersinks having a tapered tip end are provided.

Then, the pair of molds 20a, 20b described above.
The molds 20a and 20b are moved while being filled with the throw-away tip material, and the pins 21a and 21b provided on the molds 20a and 20b correspond to the other molds 20b and 20a, respectively. Protruding portion 23b,
23a to insert into the insertion holes 22b and 22a to compress the throw-away tip material between the pair of molds 20a and 20b, and the thus-compressed and molded throw-away tip material to the sintering temperature. Thirteen
Sintering was performed at 50 to 1550 ° C. to produce a sintered product in a state close to the above throw-away tip 10 for a drill.

Thereafter, the sintered product was ground to produce the throw-away tip 10 for a drill.

When the throw-away tip 10 for drills is manufactured in this manner, the material for the throw-away tip is pre-sintered as in the prior art to produce a pre-sintered insert for the tip in a soft state that is easy to process. After that, compared to the case where holes corresponding to the screw mounting holes having countersink holes are formed in this pre-sintered product for chips, holes can be easily and stably formed at accurate positions. At the same time, it is not necessary to re-sinter this temporary calcination product for chips, and the above-mentioned drill throw-away chip 10 can be easily manufactured.

Further, in the drill throw-away tip 10 according to this embodiment, each rake face 12a,
Since the angle θ of the taper portion in the countersink portion 14a of each screw mounting hole 14 provided in 12b is set to 90 °,
The protrusions 23a provided on the molds 20a and 20b,
The angle of the tapered portion at the tip of 23b can be increased, and when inserting the pins 21a and 21b into the insertion holes 22b and 22a of the protrusions 23b and 23a as described above, the pins 21a and 21b are Each insertion hole 22
Even if it hits the edge portions of b and 22a, the respective protruding portions 23b and 23a are not damaged and the above-mentioned drill throw-away tip 10 can be stably manufactured.

On the other hand, in the drill main body 30 to which the above-mentioned drill throw-away tip 10 is attached, as shown in FIGS. 3 and 4 (A) and 4 (B), the above-mentioned drill throw is provided at the tip of the drill main body 30. A tip mounting portion 31 for mounting the away tip 10 is provided from the center of rotation toward both sides, and each of the mounting surfaces 32 on both sides of the tip mounting portion 31 has a throw-away tip 10 for drilling.
A screw hole 33 corresponding to the screw mounting hole 14 having the countersink portion 14a on each of the rake faces 12a and 12b is provided, and a pair of screw grooves 34 for discharging chips continuously from the chip mounting portion 31 are formed on the drill body 30. It is arranged along the axial direction from the tip of.

When the throw-away tip 10 for a drill is attached to the tip of the drill body 30 to manufacture the throw-away drill of this embodiment, as shown in FIGS. 4 (A) and 4 (B). The drill throw-away tip 10 is attached to the tip mounting portion 31 provided at the tip of the drill body 30, and the screw holes 33 provided on the mounting surfaces 32 on both sides of the tip mounting portion 31, The screw attachment holes 14 provided on the rake faces 12a and 12b on both sides of the drill throw-away tip 10 are matched with each other, and in this state, the above-mentioned countersunk screw 13 is provided on each rake face 12a, 12b. The throw-away tip 10 for drill is screwed into each screw hole 33 provided on the mounting surface 32 of the drill body 30 through the screw mounting hole 14.
Is a tip mounting portion 3 provided at the tip of the drill body 30.
I attached it to 1 freely.

With the drill throw-away tip 10 thus mounted on the tip mounting portion 31 provided at the tip of the drill body 30, the drill throw-away tip 10 is drilled on both sides of the center of rotation. When attached to the tip of the main body 30 with the two screws 13 with the plate 13a, the throw-away tip 10 for the drill
Is now firmly attached to the drill body 30.

Further, in the throw-away type drill according to this embodiment, when the drill throw-away tip 10 is attached to the tip portion of the drill body 30 as described above, the cutting edges on both sides of the drill throw-away tip 10 are provided. Each rake face 12a, 1 continuous with 11a, 11b
The rake angle of 2b was set to + 10 ° or more.

Then, the throw-away type drill is rotated, the object to be cut is cut by the cutting edges 11a and 11b on both sides provided in the drill throw-away tip 10, and the chips are cut from the rake faces 12a and 12b. It was guided to each twist groove 34 and discharged through each twist groove 34.

Here, as described above, each rake face 12a,
When the rake angle of 12b is + 10 ° or more, this throw-away type drill is rotated and the cutting edges 11a, 11 on both sides are rotated.
When the object to be cut is cut by b, the object to be cut can be easily cut, and as described above, the chips are guided from the rake faces 12a and 12b to the respective twist grooves 34, and the respective twist grooves. If it is discharged through 34, the chips of the work piece will be discharged well through each spiral groove 34, and the conventional one with cutting edges formed on both sides of the rotation center of cemented carbide etc. by brazing The same excellent machinability and chip discharge performance as those of the above drills were obtained.

[0039]

As described above in detail, according to the present invention, a screw hole is provided in each mounting surface of the tip mounting portion provided at the tip of the drill body, and the screw holes are made to correspond to the screw holes in each mounting surface. And, there are screw mounting holes with countersink holes on the rake face of each cutting edge provided on both sides of the rotation center of the drill throw-away tip, and the countersink holes provided on each rake face of the drill throw-away tip. A throw-away type that matches the screw mounting hole with a part with the screw hole provided on each mounting surface of the drill body and firmly mounts the drill throw-away tip to the tip of the drill body with the screw with a plate. In the drill, accurately equip the rake face of the drill throw-away tip with screw holes with countersink holes so as to correspond to the screw holes on each mounting face of the drill body. Bets are easy, the fabrication of such a throw-away tip drill becomes so performed in a simple and low cost.

Further, in the throw-away type drill according to the present invention, a twist groove for guiding chips is formed in the drill body, and the rake face of each rake face of the drill throw-away tip attached to the tip of the drill body. When the angle was set to + 10 ° or more, the machinability and the chip discharge performance of the throw-away drill were significantly improved.

[Brief description of the drawings]

FIG. 1 is a front view, a plan view and a perspective view of a throw-away tip for a drill used in an embodiment of the present invention.

FIG. 2 is a cross-sectional explanatory view showing a state of manufacturing a throw-away tip for a drill in the above embodiment.

FIG. 3 is a partial explanatory view and a sectional explanatory view showing a state of a tip end portion of a drill main body to which the above-mentioned drill throw-away tip is attached in the embodiment.

FIG. 4 is a front view and a plan view of a throw-away type drill in which the above-mentioned drill throw-away tip is attached to a tip end portion of a drill body in the embodiment.

[Explanation of symbols]

 10 Throw-away tip for drill 11a, 11b Cutting edge 12a, 12b Rake surface 13 Screw with plate 13a Plate part 14 Screw mounting hole with countersink part 14a Countersink part 20a, 20b Mold 21a, 21b Hole forming pin 22a , 22b Insertion holes 23a, 23b Projection part for forming countersink 30 Drill body 31 Tip mounting part 32 Mounting surface 33 Screw hole 34 Twist groove θ Angle of tapered part in countersink part

Claims (4)

[Claims] 1. Cutting edges 11a, 11b and a rake face 12
a and 12b are provided on both sides of the center of rotation, and a throw-away tip 10 for a drill in which screw mounting holes 14 with countersinks 14a are formed on each rake face 12a, 12b.
In manufacturing, a pair of molds 20a, 20b are provided with a pair of hole forming pins 21a, 21b corresponding to the screw mounting holes 14 in the rake faces 12a, 12b and corresponding to the respective pins 21a, 21b. In this manner, each die 20b, 20a is provided with an insertion hole 22b, 22a for inserting the pin 21a, 21b, respectively, and one tip 23b, 23a for forming a countersink having a tapered tip is provided. , A material for the throw-away tip is filled between the pair of molds 20a, 20b, and the pins 21a, 2
1b is inserted into the insertion holes 22b, 22a of the corresponding projecting portions 23b, 23a to compress the material for the throw-away tip, and after sintering this material, finish processing is performed for the drill. Away chip manufacturing method. 2. Cutting edges 11a, 11b and a rake face 12
a and 12b are provided on both sides of the rotation center, and in the throw-away tip for a drill in which screw holes with countersink portions 14a are formed on each rake surface 12a, 12b, provided on each rake surface 12a, 12b. The throw-away tip for a drill, wherein the angle θ of the tapered portion of the countersink portion 14a in the screw mounting hole 14 with the countersink portion 14a is 70 ° or more. 3. A tip mounting portion 31 for mounting the drill throw-away tip 10 according to claim 2 is provided at the tip portion of the drill body 30 from the center of rotation toward both sides, and at this tip mounting portion 31. The mounting surfaces 32 on both sides are provided with screw holes 33 corresponding to the screw mounting holes 14 with the countersink portions 14a in the rake surfaces 12a and 12b of the drill throw-away tip 10, respectively. 10 is attached to the tip mounting portion 31 at the tip of the drill body 30 and each countersink portion 1 provided in each rake face 12a, 12b of the drill throw-away tip 10
The screw attachment hole 14 with 4a and the respective screw holes 33 provided on the respective attachment surfaces 32 of the tip attachment portion 31 are aligned with each other, and the drill throw-away tip 10 of the drill main body 30 is moved by the screw 13 with the plate 13a. A throw-away drill that is detachably attached to the tip. 4. The throw-away drill according to claim 3, wherein a twist groove 34 for guiding chips is formed in the drill body 30, and the drill body 30 is provided.
A throw-away drill in which the rake angles of the rake faces 12a, 12b of the above-described drill throw-away tip 10 attached to the tip of the drill are + 10 ° or more.