JPS61279410A - Throw away drill - Google Patents

Abstract

PURPOSE:To prevent a drill main unit from being flexed by a radial load, by arranging outer and inner cutting tips in one chip discharge flute while an outer cutting tip in the other chip discharge flute. CONSTITUTION:A drill arranges an outer cutting tip 4 and an inner cutting tip 5 in a chip discharge flute 2 while an outer cutting tip 7 in another chip discharge flute 3. The outer cutting tip 7 is arranged in such a manner that its end part in the internal peripheral side overlaps with the peripheral side end part of the inner cutting tip 5 in the chip discharge flute 2 in a locus of rotation. Accordingly, the drill, negating action of radial loads on the two outer cutting tips 4, 7 by each other to prevent a drill main unit 1 from being flexed during drilling, is prevented from vibrating and flexing a drilled hole.

Description

[Detailed Description of the Invention] [Industrial Application Field] This invention is an indexable drill KII, which has a removable index trap with a number of cutting tips attached to the tip of the drill body.
J! do.

[Conventional technology]

As a conventional drill for this plant, for example, g4trA (5
) and (5). This drill has two chip discharge grooves 2 and 3 extending from the tip to the rear end on the outer periphery of the drill body L, spaced apart by 10 degrees in the circumferential direction, and -10,000 chip discharge grooves. 2 (the outer cutting tip 4 that contacts the outer periphery of the drill is attached to the outside of the wall surface, and the inner cutting tip 5 that contacts the axis 0 of the drill body L is detachably attached to the inside of the same wall surface, and the other 9 chips are attached removably). A large-capacity tip 6 is removably attached to the central part of the wall surface facing the rotational direction of the discharge groove 3, and each end of the intermediate cutting tip 6 in the radial direction in the rotation locus is the inner edge of the outer cutting tip 4. The three tips 4, 5, 6 form seven cutting edges extending from the fine wire O to the outer circumference of the drill.

[Problem that the invention seeks to solve]

By the way, in the indexable drill with the above configuration, a large radial load (a load directed in the radial direction) acts on the outer cutting tip 4 that is in contact with the inner circumference of the n-loe six.The drill body is bent by this radial load, There were problems such as the drill vibrating during drilling, or the drilled hole becoming bent.

[Purpose of the invention]

The present invention was made to solve the above-mentioned problems, and an object of the present invention is to provide an indexable drill that can prevent the drill body from being bent due to radial loads.

[Structure of the invention]

In order to achieve the above object, this invention arranges an outer cutter tip and an inner cutter tip in one chip discharge groove, and the gs part on the inner peripheral side of the other chip discharge groove is arranged in one chip discharge groove. The fact that the outer cutter tip is placed on the outer peripheral side S@ portion of the inner cutter tip at an arbitrary point in the rotation locus is considered to be a special fault in the structure.

〔Example〕

Embodiments of the present invention will be described below with reference to the drawings.

Figure 1 shows an embodiment of this invention. The drill shown in this figure is different from the conventional drill mentioned above! A is that the outer cutter tip 7 is not arranged also in the chip discharge groove 3. That is, in the conventional drill described above, the outer cutting tip 4 disposed in the chip discharging groove 3 is disposed in the chip discharging groove 2.
On the other hand, in this drill, an outer cutter tip 7 which is in contact with the outer circumference of the drill is also arranged in the chip discharge groove 3. ing. Moreover, the outer cutter tip 7 has a radial width larger than that of the outer cutter tip 4, so that the inner circumference side end is aligned with the outer circumference side end of the inner cutter tip 5 in the rotation locus. ing.

Therefore, in the indexable drill having the above configuration, the outer cutting tip 4 is provided in the two chip evacuation grooves 2 and 3, respectively.
7 are arranged, and the radial loads acting on these outer cutter tips cancel each other out. Therefore, the drill body l is not bent during drilling (it is possible to prevent the drill from vibrating and the drilled hole from being bent).

In addition, the drill shown in FIGS. 2(A) and 2(U) has an outer cutting tip 8 disposed in the chip discharge groove 2 whose width is smaller than that of the outer cutting tip 4 in the above embodiment, and the inner cutting edge is made smaller by that width. The chip 5 is arranged on the outer circumferential side.

As a result, even though the outer cutter tip 9 arranged in the chip discharge groove 3 is of the same width as the inner cutter tip 5 arranged in the chip discharge groove 2, the inner peripheral side end of the outer cutter tip 9 m at the outer circumferential end of the inner cutting tip 5 in the rotation locus. Note that as a result of arranging the inner cutter tip 5 toward the outer circumferential side, the inner cutter tip 5 is spaced apart from the axis sO. Therefore, in the chip discharge groove 3, the outer circumferential end is attached to the inner circumferential side ga portion of the inner cutter tip 5 in the rotation locus '1! L and axis O
I am busy arranging a circular chip lO that is in contact with K.

Furthermore, the drill shown in Figure 3, β) is shown in Figure 2 (8).
This is a modified example of the drill shown in , (3), in which an equilateral triangular tip is used as the outer cutting tip 11 disposed in the chip discharge groove 3.

〔Effect of the invention〕

As explained above, according to the indexable drill of the present invention, the outer cutting tip and the inner cutting tip are arranged in one chip discharging groove, and the inner circumferential end is placed in the other chip discharging groove. Since the outer cutter tip is arranged at the outer circumferential side m of the inner cutter tip of the chip evacuation groove, the outer cutter tip is arranged at an arbitrary position in the rotation locus.
The radial loads acting on the two outer cutting tips cancel each other out, thus preventing the drill body from bending during drilling (preventing the drill from vibrating or bending the drilled hole). Effects such as this can be obtained.

[Brief Description of the Drawings] Fig. 7, Fig. 2, and Fig. 3 each show an embodiment of the present invention. An example of a conventional indexable drill is shown. Figure 3) is a top view, and Figure 3) is a partially omitted side view. l...Drill body, 2, 3...Chip discharge groove, 4゜7, 8, 9.11...Outer blade tip,
5...Inner blade tip, O...Axis line.

Claims (1)

[Claims] Two chip evacuation grooves are formed on the outer periphery of the drill body, extending from the tip to the rear end, spaced approximately 180 degrees apart in the circumferential direction, and one chip ejection groove is formed on the outer periphery of the wall facing the rotation direction of the drill body. An outer cutter tip that is in contact with the outer cutter tip is removably attached, and an inner cutter tip that is spaced apart in the radial direction from the outer cutter tip is detachably attached to the inner peripheral side of the same wall surface, and the rotation direction of the other chip evacuation groove is The outer edge of the inner cutting edge is in contact with the outer periphery of the drill, and the inner edge of the inner cutting edge is placed in one of the chip evacuation grooves. A throw-away drill featuring a removable tip.