JP2000033510A - Drilling tool - Google Patents

Abstract

(57) [Summary] [PROBLEMS] To reduce the thrust force acting at the time of drilling, to easily form and regrind the tool body 11, and to efficiently supply a cutting oil or the like to the inner peripheral side of the tool. To provide a drilling tool capable of A pair of chip discharge grooves (13) extending in the direction of the axis (O) are formed symmetrically with respect to the axis (O) on the outer periphery of the tip of a substantially cylindrical tool body (11) rotated around the axis (O). At the same time, the tip flank 1 between the wall surface of these chip discharge grooves 13, 13 facing the tool rotation direction T and the tool body 11.
In a drilling tool in which cutting edges 15 and 15 are formed at the intersection ridges of the cutting edges 4 and 14, supply holes 17 for cutting oil or the like are formed in the tool body 11 along the axis O.
Is opened on the axis O at the tip flank surfaces 14 and 14.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a drilling tool in which a supply hole for supplying a cutting oil or the like is formed in a tool body.

[0002]

2. Description of the Related Art In a drilling tool of this kind, a pair of chip discharge grooves 2, 2 are formed on an outer peripheral portion of a tip end of a substantially cylindrical tool body 1 rotated around an axis O as shown in FIG. The chip discharge grooves 2, 2 are formed symmetrically with respect to the axis O and twisted about the axis O, and the wall faces of the chip discharge grooves 2, 2 facing the tool rotation direction T, and the tip flank faces 3, 3 of the tool body 1. The cutting edges 4 and 4 are sharpened together at the intersection ridge line of
A so-called two-blade solid drill or a twist drill is generally known. Here, thinning blades 5, 5 are formed by performing thinning on the tool inner peripheral side of the cutting blades 4, 4, and these thinning blades 5, 5 are connected to the axis O at the tip of the tool body 1. A chisel portion 6 is formed by crossing the upper portion. Further, supply holes 7, 7 for supplying a cutting oil or the like to the tip of the tool at the time of drilling are provided on the rear side of the cutting edges 4, 4 of the tip flank surfaces 3, 3 in the tool rotation direction T. It is opened at a position away from the outer peripheral side.

[0003]

However, in such a drilling tool, the peripheral speed becomes zero on the axis O at the tip of the tool main body 1, so that the work material is cut around the chisel portion 6. Rather, it is known that a crushing cutting form is formed, and thereby a large thrust force acts. However, the above-mentioned thinning is performed in order to suppress such an increase in the thrust force. However, as long as the peripheral speed becomes zero in the chisel portion 6, no matter how the thinning is performed, the thinning is performed around the chisel portion 6. The acting thrust force cannot be zero.

In drilling with such a two-blade solid drill, the chisel portion 6 of the tool body 1 is first pushed into the work material, and then the thinning blades 5, 5 are moved into the work material. , And thereafter the drilling is performed by the cutting blades 4, 4. Therefore, if the chisel portion 6 is displaced from the axis O, the tool main body 1 oscillates and the machining accuracy is impaired. For this reason, when thinning the tool body 1 to define the chisel portion 6, it is necessary to perform precision polishing so that the chisel portion 6 is accurately positioned on the axis O. There was a problem that labor would be spent. Further, particularly in such a solid drill, when the cutting edge 4 or the thinning blade 5 is worn, the tip flank surfaces 3 and 3 of the tool body 1 are sharpened and newly added to the cutting edge 4 and the thinning blade 5.
The tool body 1 is reused by performing so-called re-polishing such as forming a chisel portion 6. However, even in the case of such re-polishing, the above-described conventional drilling tool has the above-described configuration. Since such precision polishing is required, it has been difficult to re-grind the tool body 1 at a drilling work site, for example.

On the other hand, the supply holes 7, 7 for supplying a cutting oil or the like to the tool tip end are provided on the tip flank surfaces 3, 3 on the rear side of the cutting edges 4, 4 in the tool rotation direction T as described above. The cutting oil is formed so as to open at a position distant from the axis O, so that the cutting oil is smoothly supplied to the cutting blades 4, 4, but a large thrust force is present near the axis O on the inner peripheral side of the tool. It is unavoidable that the supply of the cutting oil to the chisel portion 6 and the thinning blade 5 around the chisel portion 6 on which the action is effected becomes short. For this reason, in the conventional drilling tool described above,
There is also a problem that wear of the tool main body 1 in these portions becomes remarkable, and further increases the thrust force.

The present invention has been made under such a background, and it is possible to reduce a thrust force acting at the time of drilling, easily form and regrind the tool body, and furthermore, to cut the inner circumferential side of the tool. An object of the present invention is to provide a drilling tool capable of efficiently supplying an oil agent or the like.

[0007]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems and to achieve such an object, the present invention relates to a method of manufacturing the above-described apparatus, comprising the steps of: A pair of chip discharge grooves extending in the direction are formed symmetrically with respect to the axis, and at the intersection ridge portion between the wall surface of the chip discharge grooves facing the tool rotation direction and the tip flank of the tool body. In a drilling tool having a cutting edge formed therein, a supply hole for cutting oil or the like is formed in the tool main body along the axis, and the supply hole is opened on the axis in the flank surface of the distal end. It is characterized by.

Accordingly, according to such a drilling tool,
First, the supply hole for cutting oil etc. is open on the axis at the tip flank of the tool body, that is, since the chisel part does not exist on the axis where the largest thrust force acts at the time of drilling, The thrust force acting on the chisel portion can be reduced, so that the thrust force of the entire tool body can be reduced. In addition, since the chisel portion itself does not exist on the axis of the tool body, it is not necessary to perform precision polishing to accurately define the chisel portion on the axis,
The production and re-polishing of the drilling tool can be facilitated. Moreover, since the supply hole for the cutting fluid is opened on the axis of the flank of the tip of the tool body, it is possible to efficiently supply the cutting fluid to the thinning blades and the like around the axis. Can be reduced.

Here, the supply hole may have a circular cross section, but the supply hole has an appropriate directionality in the supply direction of the cutting oil or the like on the flank of the tip to achieve efficient supply. For this purpose, it is desirable that the supply hole is formed so as to extend in the radial direction with respect to the axis and open at the flank of the distal end, and to extend in the radial direction with respect to the axis in a cross section orthogonal to the axis. In this case, in particular, in a twist drill or the like in which the chip discharge groove is formed to be twisted around the axis, the supply hole is twisted around the axis in accordance with the twist of the chip discharge groove. With such a configuration, even if the tool body is polished again, the positional relationship between the supply hole and the chip discharge groove or the cutting blade can be kept constant, and the supply efficiency of the cutting oil or the like can be maintained. Alternatively, even when a thinning blade is formed, the shape can be maintained and the tool performance can be stabilized.

When the thinning blade extending toward the axis is formed on the inner peripheral side of the tool of the cutting blade as described above, the supply hole is formed in the flank of the distal end along the radial direction with respect to the axis along the thinning blade. If it is opened so as to extend, the cutting oil or the like supplied from the supply hole can be guided to the thinning blade or the cutting blade to achieve efficient cooling and lubrication. On the other hand, when the thinning blade extending toward the axis is formed on the inner peripheral side of the tool of the cutting blade, the supply hole is formed at the flank of the distal end in the direction perpendicular to the thinning blade. If the opening is formed so as to extend in the radial direction with respect to the thickness, the thickness between the groove bottom of the chip discharge groove and the supply hole can be ensured, and by providing the supply hole along the axis, tool rigidity is impaired. Can be prevented.

[0011]

Embodiments of the present invention will be described below with reference to the drawings. FIGS. 1 to 3 show a first embodiment of the present invention. In this first embodiment, a tool body 11 is made of a hard material such as a cemented carbide and the like, as shown in FIG. The rear end portion is formed as a shank portion 12, and the outer periphery of the front end portion is directed toward the rear side in the tool rotation direction T in the direction of the axis O toward the rear end side of the tool. A pair of twisted chip discharge grooves 13, 13 are formed axially symmetric with respect to the axis O, and the tool discharge direction T of these chip discharge grooves 13, 13 is set.
A wall facing the side, a tip flank 14 at the tip of the tool body 11,
Cutting edges 15, 15 are formed in the ridge line crossing with 14.

Thinning blades 16, 16 are formed on the inner peripheral side of the cutting edges 15, 15 by thinning the tip of the tool body 11, and these thinning edges 16, 16 are formed. As shown in FIG. 2 when viewed from the tool tip side, is formed so as to intersect the cutting edges 15 at an obtuse angle and extend toward the axis O at the tip end of the tool body 11. In the present embodiment, the tip flank 14 is constituted by a plurality of flank surfaces whose clearance angles gradually increase from the cutting edge 15 and the thinning blade 16 toward the rear side in the tool rotation direction T. The intersection ridge L between the first flank 14a connected to the cutting edge 15 and the thinning blade 16 and the second flank 14b connected to the first flank 14a on the rear side in the tool rotation direction T is: As shown in FIG. 2, the second flank 14b is formed so as to be parallel to the cutting edge 15 as viewed from the tool tip side, and further behind the second flank 14b in the tool rotation direction T. Is formed in a direction orthogonal to the thinning blade 16 when viewed from the tool tip side.

The tool body 11 is inserted into the tool body 11 along the axis O inside the tool body 11.
A supply hole 17 for cutting oil or the like is formed so as to penetrate the front end flank surfaces 14 from the rear end surface 2 and open on the axis O at the front end flank surfaces 14. In this embodiment, as shown in FIG. 2, the supply hole 17 has a rectangular slit extending from the axis O in the diametric direction with respect to the axis O with the axis O as the center in the longitudinal direction as viewed from the tool tip side. Tip flank 14, 1
4, and especially the supply hole 17 is provided at the tip flank 1.
The rectangle formed by opening at 4, 14 is the thinning blade 1
6, 16 and both thinning blades 16, 16
Are arranged on the side of the tool rotation direction T.

In addition, the supply hole 17 has a rectangular shape which is the same as the above-mentioned rectangle opening at the tip flank surfaces 14, 14 even in a cross section perpendicular to the axis O, that is, with the axis O as the center in the longitudinal direction. It is extended toward the tool rear end side so as to form a rectangular shape extending in the diameter direction with respect to the axis O. However, in the present embodiment, the supply holes 17
In accordance with the fact that the chip discharge grooves 13 are formed to be twisted around the axis O, the chip discharge grooves 13
In the same direction at the same twist angle, that is, the tool rotation direction T around the axis O toward the tool rear end side.
Is formed to be twisted backward. In order to form such a twisted supply hole 17 in the tool body 11 made of cemented carbide, for example, a molded body fired in the tool body 11 is prepared by adding an appropriate plasticizer to the raw material powder of cemented carbide. Along with forming the added molding material by extrusion press forming while twisting, a core having a rectangular plate twisted in the same manner as the supply hole is arranged in a molding mold at the time of this extrusion press forming. The supply holes may be formed at the same time when the formed body is extruded and pressed.

However, in the drilling tool configured as described above, the supply hole 17 is open on the axis O at the tip flank surfaces 14 and 14 at the tip of the tool body 11, so that the axis O There is no chisel on the top, so that no large thrust force acts on the chisel on the axis O where the peripheral speed becomes zero, and the tool body 11
The thrust force acting on the whole can be significantly reduced. In addition, since the chisel portion does not exist on the axis O, when the drilling tool is manufactured, or when the cutting blade 15 or the thinning blade 16 is worn and re-ground, the chisel portion is not provided on the axis O. It is no longer necessary to perform precision polishing in order to accurately define the chisel portion, and it is possible to reduce the time and labor by simplifying the manufacturing operation and the re-polishing operation.

Further, since the supply hole 17 is opened on the axis O, the cutting oil or the like supplied from the supply hole 17 first moves around the axis O where the large thrust force acts as described above. As a result, the wear and overheating around the axis O at the tip of the tool main body 11 due to such a large thrust force can be effectively suppressed, thereby extending the tool life and preventing the occurrence of welding and the like. It can be reliably prevented. In particular, in this embodiment,
The supply hole 17 is formed in a rectangular shape extending in a diametric direction with respect to the axis O with the axis O as a center in the longitudinal direction in a cross section orthogonal to the axis O. The supply holes 17 are open so that the cutting oil or the like is spread in the longitudinal direction of the rectangle by centrifugal force caused by the rotation of the tool body 11.
Therefore, by appropriately setting the direction of the rectangle formed by the supply holes 17 opening to the flank surfaces 14, 14, the wear and overheating of the tool body 11 can be more effectively suppressed. It becomes possible.

More specifically, in the present embodiment, thinning blades 16, 16 extending toward the axis O are formed on the inner peripheral side of the cutting blades 15, 15 at the tip of the tool body 11, and the supply holes are formed. The rectangle 17 is formed so as to extend in the radial direction with respect to the axis O along the thinning blades 16, 16. A thinning blade 16, on which a large thrust force acts on the inner peripheral side,
16 and then flows out to the outer peripheral side of the tool and the cutting edge 1
5 and 15. For this reason, according to the present embodiment, a cutting oil or the like is first supplied to the thinning blades 16, which are liable to cause abrasion and overheating due to a large thrust force, to cool and lubricate them reliably and efficiently. Therefore, it is possible to more effectively suppress and prevent the shortening of the tool life due to wear and the welding due to overheating.

Furthermore, in this embodiment, the tool body 1
In contrast to the above-described twist drill, the chip discharge grooves 13 formed in the outer peripheral portion of the tip 1 are twisted toward the rear side in the tool rotation direction T as going toward the tool rear end in the direction of the axis O. The supply hole 17 is also formed to be twisted toward the rear side in the tool rotation direction T toward the tool rear end side around the axis O in accordance with the twist of the chip discharge grooves 13, 13. The distal end of the main body 11 has the same cross section orthogonal to the axis O at any position. Therefore, according to the present embodiment, the cutting blade 1
Even when the tool body 11 is polished again due to wear of the blades 5, 15 and the thinning blades 16, 16, the positional relationship between the cutting holes 15, 15 and the thinning blades 16, 16 and the supply holes 17 is fixed. That is, as described above, the cutting oil or the like is first supplied to the thinning blades 16 and 1.
6, the effect that reliable and efficient cooling and lubrication can be achieved can be maintained, and the thinning blade 1 extending from the cutting blades 15, 15 to the tool inner peripheral side at the time of re-polishing.
Also when forming 6,16, it is possible to maintain the same shape as before repolishing and obtain stable tool performance.

Next, FIGS. 4 to 8 show second to fifth embodiments of the present invention, in which constituent elements common to the first embodiment are assigned the same reference numerals. The description is omitted. First, in the second embodiment shown in FIG. 4, the supply hole 21 for the cutting oil or the like is formed in a stepped manner from the axis O along the thinning blades 16, 16 in the radial direction with respect to the axis O from the tool tip side. It is formed so as to form a pair of elongated rectangles and opens to the front end flank surfaces 14, 14, so that the same effects as those of the first embodiment can be obtained, and the inner circumference of the thinning blades 16, 16. Since the end can be close to the axis O, by forming the supply hole 21 so as to open on the axis O, it is possible to more reliably prevent a situation in which the workpiece is left uncut during drilling. Can be.

On the other hand, in the third to fifth embodiments shown in FIGS. 5 to 8, the supply holes 17 and 21 of the first and second embodiments have a diameter with respect to the axis O along the thinning blades 16 and 16. While it was formed to extend in the direction,
The supply hole is formed so as to extend in the radial direction with respect to the axis O in the direction perpendicular to the thinning blades 16, 16 when viewed from the tool tip side. That is, the third
In the embodiment, the supply hole 22 is formed so as to open to the tip flank surfaces 14 and 14 in a rectangular shape with the axis O as the center in the longitudinal direction as in the first embodiment, as viewed from the tool tip side. However, in the first embodiment, this rectangle extends along the thinning blades 16, 16, whereas in the third embodiment, the direction orthogonal to the thinning blades 16, that is, the tip flank surface 14. Of the second flank 14
The third flank 14c is formed so as to extend along the intersection ridge M of the third flank 14c.

However, in the third embodiment, the supply hole 22 is formed in a cross section orthogonal to the axis O.
Chip discharge grooves 13 in the circumferential direction of the drill body 11
First and second embodiments in which the supply holes 17, 21 are formed in the direction connecting the chip discharge grooves 13, 13 because they are formed to extend in the direction connecting the lands defined between them. The thickness of the tool body 11 can be sufficiently ensured between the supply hole 22 and the bottom of the chip discharge grooves 13, 13, and the supply hole 22 is formed along the axis O. It is possible to prevent a situation in which the rigidity of the tool main body 11 is impaired, and to promote more stable drilling.
In addition, since the supply holes 22 are not formed along the thinning blades 16, the bevel angles of the thinning blades 16, 16 do not become small at the supply hole 22, and the thinning blades 16, 16 are damaged. Is also obtained.

Further, in the first to third embodiments, the supply holes 17, 21, and
22 are formed so as to have a rectangular shape extending in the radial direction with respect to the axis O.
As in the embodiment, the supply hole 23 may be formed in an elliptical shape extending in the radial direction with respect to the axis O of the tool body 11, or may be formed in an elliptical shape in which both ends of a rectangle are semicircular. Good. Further, as in the fifth embodiment shown in FIGS. 7 and 8, the rectangular end formed by the supply hole 24 may be shaped such that its width becomes wider toward the outer peripheral side of the tool. As shown in FIGS. 7 and 8, if the supply hole 24 is formed such that the circumferential width of the supply hole 24 becomes wider toward the rear side in the tool rotation direction T as it goes toward the tool outer peripheral side, the supply hole 24 at the tool outer peripheral side of the supply hole 24 is formed. It is possible to supply more cutting fluid and the like, and the tip flank 1
4 and 14, the supply holes 24 are provided with thinning blades 16 and 16 respectively.
Is supplied to the thinning blades 16, 16 and the cutting blades 15, 15 located on the rear side of the supply hole 24 in the tool rotation direction T even if they are formed so as to extend in the direction orthogonal to. be able to.

In the first to fifth embodiments, the supply holes 17, 21, 22, 23, and 24 are formed so as to extend in a radial direction with respect to the axis O in a cross section orthogonal to the axis O. However, for example, a cross section perpendicular to the axis O may be formed so as to form a circle centered on the axis O. Even in this case, the cutting blades 15, 15 and the thinning blade 16, With a constant positional relationship between the supply holes 16 and the supply holes, stable tool performance can be obtained. Further, the supply holes 17, 21, 22, 23, 24
Can be used to supply, for example, cooling air or the like in addition to supplying the cutting fluid to the tool tip side.

[0024]

As described above, according to the present invention,
Since the supply hole for cutting oil etc. is open on the axis at the flank of the tip of the tool body, no chisel is formed on this axis, and it acts on the chisel on this axis during drilling. Large thrust force to reduce the thrust force acting on the entire tool body.
This thrust force prevents wear at the tip of the tool body or prevents a situation in which excessive heat is generated between the workpiece and welding, thereby extending the life of the tool and ensuring a smooth hole. It is possible to encourage dawning. In addition, since the chisel portion does not exist on the axis as described above, it is not necessary to perform precision polishing to accurately define the chisel portion on the axis, and it is easy to manufacture and re-polish the drilling tool. It can be. In addition, cutting oil can be efficiently supplied to the thinning blades and cutting blades on the tool inner peripheral side located on the periphery from the supply holes opening on the axis of the flank of the tip, further reducing the thrust force. Can be achieved.

[Brief description of the drawings]

FIG. 1 is a side view showing a first embodiment of the present invention.

FIG. 2 is an enlarged front view of the embodiment shown in FIG. 1 as viewed from a tool tip side.

FIG. 3 is a side view as viewed in the X direction in FIG. 2;

FIG. 4 is an enlarged front view showing a second embodiment of the present invention as viewed from a tool tip side.

FIG. 5 is an enlarged front view showing a third embodiment of the present invention as viewed from a tool tip side.

FIG. 6 is an enlarged front view showing a fourth embodiment of the present invention as viewed from a tool tip side.

FIG. 7 is an enlarged front view showing a fifth embodiment of the present invention as viewed from a tool tip side.

FIG. 8 is a side view as viewed in the X direction in FIG. 7;

FIG. 9 is an enlarged front view showing a conventional drilling tool as viewed from a tool tip side.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 11 Tool main body 13 Chip discharge groove 14 Tip flank 15 Cutting blade 16 Thinning blade 17, 21, 22, 23, 24 Supply hole for cutting oil etc. O Axis line of tool main body 11 T Tool rotation direction

Claims (4)

[Claims] 1. A pair of chip discharge grooves extending in the axial direction are formed symmetrically with respect to the axis on the outer periphery of the tip of a substantially cylindrical tool body rotated about the axis. In a drilling tool in which a cutting edge is formed at an intersection ridge line between a wall surface of a chip discharge groove facing a tool rotation direction and a flank of a tip of the tool body, the tool body includes a cutting oil along the axis. Supply holes are formed,
The drilling tool is characterized in that the supply hole is opened on the axis at the flank surface of the tip. 2. The chip discharge groove is formed to be twisted around the axis, and the supply hole is formed to extend in a radial direction with respect to the axis in a cross section orthogonal to the axis. The drilling tool according to claim 1, wherein the drilling tool is formed so as to be twisted around the axis in accordance with the twist of the discharge groove. 3. A thinning blade extending toward the axis is formed on the inner peripheral side of the tool of the cutting blade, and the supply hole has a diameter with respect to the axis along the thinning blade at the tip flank. The drilling tool according to claim 2, wherein the drilling tool is opened so as to extend in the direction. 4. A thinning blade extending toward the axis is formed on a tool inner peripheral side of the cutting blade, and the supply hole is formed in the tip flank in a direction perpendicular to the thinning blade. The drilling tool according to claim 2, wherein the opening is formed so as to extend in a radial direction with respect to the axis.