JPS5840209A - Drill - Google Patents

Abstract

PURPOSE:To perform high accurate drilling work, by continuously performing the drilling work from preliminary hole machining to finish machining, that is, by not only providing point end lips to the point end of a drill but also providing finishing lips and margins behind the point end lip. CONSTITUTION:The bottom surface of a hole is cut by point end lips 33, and then an internal wall surface of the hole is performed with finish cutting by finishing lips 43. Though a cutting chip 71 is formed at cutting work by the point end lip 33, finish cutting of the internal wall surface 7 of the hole can be performed by the finishing lip 43. A drill is stably held to the internal wall surface of the hole by peripheral lips 35 (or margin), provided following to the lips 33, and margins 44, provided following to the lips 43, and run-out of the drill is not caused to smoothly perform cutting work. At machining, cutting oil is supplied from an oil hole opening 61.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a drill capable of drilling and cutting with high precision and excellent surface roughness.

Conventionally, drills have generally only had a tip cutting edge that draws an almost conical rotation trajectory only at the tip, and there is no cutting edge on the outer circumferential surface of the drill. A width margin is formed. In addition, even in carbide drills with a carbide tip attached to the tip of the drill, the cutting edge is only provided at the tip of the tip, and there is no cutting edge on the outer circumference of the tip, and the outer circumference of the tip is used as the drill body. An arcuate surface concentric with the outer circumferential surface was used as a margin with a width corresponding to the chip thickness.

With such conventional drills, the cutting action is performed only by the cutting edge at the tip of the drill, so even if cutting conditions such as rotation speed and feed are improved, the surface roughness of the inner wall surface of the hole will not improve. That is difficult. In other words, in this type of drilling, when chips are formed and discharged, the chips interfere with the inner wall surface of the hole, and the inner wall surface of the hole is damaged by the chips.As a result, the surface roughness of the inner wall surface of the hole decreases, especially when the welded structure is damaged. For drilling of rolled steel materials (S M),
Since the inner wall surface of the hole is easily damaged, it is difficult to improve its roughness, and the roughness could only be processed to about 208.

The purpose of the present invention is to eliminate these drawbacks of conventional drills, and its features include not only providing a tip cutting edge at the tip of the drill, but also providing finishing at the rear of this tip cutting edge. By providing a cutting edge and a margin, cutting with the cutting edge at the tip, and finishing the inner wall surface damaged by the chips with the finishing cutting edge, the surface accuracy and surface roughness of the inner wall surface of the hole can be greatly improved. There are points that could be improved. Another feature is that cutting oil can be supplied to both the cutting part by the tip cutting blade and the cutting part by the finishing cutting blade, which prevents seizure of both cutting blades and improves the life of the drill. The point is that we have made it possible.

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

Reference numeral 1 designates a drill body, which has two helical grooves 2°2 on its outer circumferential surface, and carbide tips 3, 3 are fixed to the tips thereof by brazing or other means, and the front surface of the tips 3, 3 rotates. Rake face 31. si and a flank 32 on the tip surface.
By forming 32, tip cutting edges 33, 33 are formed at the intersection edges of these surfaces 31, 31 and 32, 32.

The tip cutting edge 33.33 has a cutting edge starting end near the center of rotation of the drill when viewed from the bottom, and center cutting edge portions 33a, 35a forming a curve convex with respect to the rotation direction near the center of rotation;
Continuing from this, a linear peripheral cutting edge portion 33b reaches the cutting edge end near the outer peripheral edge.

53b, and is formed so that its rotation locus is approximately conical when viewed from the front.

The rake face 31.31 has a curved central cutting edge 35a.
, 55a are the center cutting edge portions 53a, 33.
A circular surface drawn with the radius of curvature R of a is the bottom surface, and an arbitrary point on the rotation axis of the drill is a conical surface, and the portions corresponding to the peripheral cutting edges 35b and 33b are formed on the conical surface. It is a continuous flat surface. In this embodiment, the outer (circumferential) surfaces of the tips 6 and B protrude radially outward from the outer circumferential surface of the drill body 1, and flank surfaces 34 and 34 are formed in this portion. 34.34 and the above scoop 31.31
An outer peripheral cutting edge 35.3 extends rearward along the helical grooves 2, 2 from near the end of the cutting edge of the tip cutting edge 33.33.
5 is formed. In this case, the outer surface of the tip 3.3 is connected to the outer peripheral surface i1 of the drill body 1. The arc surface is concentric with ii, and the margin is formed at which part, and the outer cutting edge is 35.55 mm.
may be omitted.

Furthermore, in this drill, the carbide tips 4, 4 are also fixed to the intermediate portion of the twisted portions 2, 2 by brazing or the like, and rake faces 41, 41 are formed on the rotating front surface of the tips 4, 4. At the same time, by forming flank surfaces 42 and 42 on the tip surfaces, a finishing cutting edge 43 degrees 43 is formed at the intersection edge of these surfaces 41 degrees 41 and surfaces 42 and 42, and the tips 4 and 4
Margins 44, 44 are formed on the outer (peripheral) surface of.

The rake faces 41, 41 are formed on the wall surfaces of the helical grooves 2, 2. In addition, the outer peripheral surfaces 11, 11 of the drill body 1
, a circumferential groove 5 is formed in a portion corresponding to directly below the chips 4, 4.
. 42.4
2 and the scoops 41, 41 create a wide finishing cutting edge 4.
3.43 is formed.

The finishing cutting edge 43.43 is formed into a straight line having a predetermined width in the radial direction, and the rotation radius of the inner peripheral end is equal to or less than the rotation radius of the outer peripheral cutting edge 55.35, and the rotation of the outer peripheral end is controlled. By making the radius larger than the rotation radius of the outer circumferential cutting edge, it is formed so as to draw an annular rotation locus with at least a portion protruding outward in the radial direction than the outer circumferential cutting edge 33.55 when viewed from the bottom.

In addition, from the outer circumferential end of the tip cutting edge 35 to the cutting edge 4
The distance H to 3.43 shall be one or more of the radius of rotation of the 66°330 outer peripheral edge of the cutting edge. The outer circumferential surface of the tip 4.4 is an arcuate surface concentric with the outer circumferential surface 11.11 of the drill body 1, and projects radially outward from the outer circumferential surface 11.11. (A negative land is formed on each cutting edge of the blades 43 and 46 on one side.

Further, the drill is provided with oil/water 6 along the axial direction, and its tip is placed in two places on the tip face of the drill body 1 and in the helical groove 2.
Openings are made at two locations corresponding to the upper positions of the finishing cutting blades 43 and 46 on the bottom surface of the cutting edge 2, respectively. 61.61 and 62.62 indicate the openings. Note that the rear end of the oil/water 6 is opened at the rear end of the drill body 1.

When drilling a hole with the above-mentioned drill, first, the bottom of the hole is cut using the cutting edge 53.55 at the tip, and then the inner wall surface of the hole is finished cut using the finishing cutting edge 43.45.

At this time, when cutting with the cutting edge 36° 33, chips 7
1 is formed as shown in FIG.
Finish cutting is done at ゜43. Furthermore, during the above-mentioned cutting, the peripheral cutting edges 35, 35 following the tip cutting edge 33.35
(or margin) and the margin 44.44 following the finishing cutting edge 43.43, the drill is stably held in a normal position with four-point support against the inner wall surface of the hole, preventing runout from occurring. However, cutting is done smoothly.

This greatly improves the surface accuracy and surface roughness of the inner wall surface of the hole.

Further, during the above-mentioned drilling process, cutting oil or the like is supplied from the tip openings 61.61 and 62.62 of the oil/water 6 to the cutting portion by the tip cutting blade 53.63 and the cutting portion by the finishing cutting blade 43° 43, respectively. By doing so, it is possible to prevent seizure of each cutting edge, and in particular, even when finish cutting the inner wall surface of the hole with the finishing cutting edge 45.45 after the tip cutting edge 33.55 has penetrated the hole, this finish can be prevented. Smooth finishing cutting can be performed without seizing of the cutting edge 45. 450 In the above drill, the grooves 2, 2 may be straight, and the peripheral grooves 5, 5 and the negative land at the tip of each cutting edge may be straight. It can be omitted. Further, the cutting edge starting end of the tip cutting edge 53.53 may be located at a position away from the drill rotation center,
The specific shape of each part such as the bottom shape of the tip cutter 56°65, the shape of each cutting edge, rake face, flank face, etc. is not particularly limited and can be arbitrarily determined as desired. However, especially if the structure is as in the above embodiment, heavy cutting is possible, and the cutting can be performed with high precision and excellent precision. Incidentally, when drilling holes in rolled material for welded structures using the drill of the above example, the surface roughness should be 2 to 2.
It is possible to add up to 2.58. The drill of the present invention is not limited to drilling holes in the above-mentioned rolled steel materials for welded structures, but can also be used to drill holes in other steel materials with the same excellent surface accuracy and roughness. be.

As explained above, according to the present invention, by drilling, so-called pilot hole machining to finishing machining (reamer machining) is performed.
It can be carried out continuously up to 100 degrees, and it can achieve a finish that is superior to that of reaming and is extremely efficient. Also,
By opening the tip of the oil filler both near the tip cutting edge and near the finishing cutting edge, finishing after penetrating the hole can be done smoothly. −

[Brief explanation of the drawing]

The figures show an embodiment of the present invention, in which Fig. 1 is a front view, Fig. 2 is a side view, Fig. 6 is a bottom view of the tip of the drill, Fig. #14 is a sectional view taken along the line 311-III in Fig. 1, FIG. 5 is a schematic cross-sectional view showing the six-hole drilling state. 1...Drill body, 2.2...Twisted groove, 6,3.
...Carbide tip (tip), 4.4...Carbide tip (medium flit), 5.5...Peripheral groove, 33,33...Tip cutting edge, 65°35...Peripheral cutting Blade, 43.43... Finish cutting edge, 44° 44... Margin. Patent applicant Toshiaki Hosoi Agent Patent attorney Etsuji Kotani Figure 1 Figure 2 Figure 3 Figure 4

Claims (1)

[Scope of Claims] 1. A tip cutting edge that draws a substantially conical rotation locus is provided at the tip of the drill, and a predetermined length of circumferential cut is made on the outer circumferential surface of the drill from near the outer circumferential end of the tip cutting edge along the drill groove. A blade or margin is installed 1, and behind it is a finishing cutting edge that draws an annular rotation locus that protrudes outward beyond the outer peripheral cutting edge or margin with respect to the 7'M JJ direction, and the outer peripheral edge of the finishing cutting blade is installed. A margin of a predetermined length along the drill groove is provided rearward from the tip, and the distance from the outer circumferential edge of the tip cutting edge to the finishing cutting edge is 91/2 or more with the rotation radius of the outer circumferential edge of the tip cutting edge. A drill characterized by: 2. A tip cutting edge that draws a substantially conical rotation locus is provided at the tip of the drill, and an outer circumferential cutting edge or margin of a predetermined length along the drill groove is provided on the outer peripheral surface of the drill from near the outer peripheral end of the tip cutting edge. , at the rear thereof, a finishing cutting edge is provided which draws an annular rotation locus protruding outward from the outer circumferential cutting edge or the margin in the radial direction, and from the outer circumferential end of the finishing cutting edge to the rear. Provide a margin of a predetermined length along the drill groove,
And, the distance from the outer circumferential end of the tip cutting edge to the finishing cutting edge is 1/2 or more of the rotation radius of the outer circumferential edge of the tip cutting edge, and furthermore, oil water is provided in this drill, and the rear end of the oil water is is opened at the rear end of the drill, and the tip of the oil and water is opened near the finishing cutting edge at the middle of the drill tip and the drill groove.