JP2008173727A - Drill - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a drill which can promote the discharge of chips and also can excellently carry out a cutting operation while preventing the contact of the chips to opening end machining blades. <P>SOLUTION: First chip discharging flutes 20 are provided on a drill body so as to twist toward the rear side of the rotational direction T of the drill with the distance from the front end side of the drill body toward the rear end side, and also second chip discharging flutes 30 are provided on the drill body such that the second chip discharging flutes 30 are continued to the rear side of the first chip discharging flutes 20, and are recessed from the wall surfaces 20A of the first chip discharging flutes 20 facing the front side of the rotational direction T of the drill toward the rear side of the rotational direction T of the drill, and elongate in parallel to the axis O of the drill. Drilling blades 22 are arranged at the tip ends of the first chip discharging flutes 20. The opening end machining blades 32 are arranged at the tip ends of the second chip discharging flutes 30 so as to be a little shifted toward the rear side of the rotational direction T of the drill from the wall surface 20A of the first chip discharging flutes 20 facing the front side of the rotational direction T of the drill. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a drill for forming a machining hole in a workpiece and chamfering or counterboring the opening end of the machining hole.

As this type of drill, for example, as disclosed in Patent Documents 1 and 2, a drill blade is provided at the tip of the drill body rotated about the axis, and the drill body is opened at the rear end side of the drill body. The thing provided with the edge processing blade is proposed.
In such a drill, the drill body is rotated around the axis and sent toward the tip in the axial direction, so that the drill blade forms a machining hole in the work material and the open end machining blade works. By chamfering or counterboring the opening end of the processed hole by cutting the opening end of the hole.
Japanese Utility Model Publication No. 58-40311 JP 2005-138258 A

By the way, in the drill currently disclosed by patent document 1, the chip | tip discharge groove | channel which extends along an axis line from the front-end | tip of a drill main body toward a rear end is formed, and the wall surface which faces the drill rotation direction front side of this chip | tip discharge | emission groove | channel. Among them, a cutting insert as a drill blade is attached to the tip portion of the drill body. In addition, a recess recessed in the drill rotation direction rear side is formed in the rear end portion of the drill body in the wall surface facing the drill rotation direction front side of the chip discharge groove, and the opening end machining blade is provided in the recess. ing.
In the drill having such a configuration, the chip discharge groove is formed so as to extend parallel to the axis, so that the chips generated by cutting with the drill blade can be guided to the rear end side of the drill body. Therefore, the chips remain inside the processed hole, and the chips may damage the inner wall surface of the processed hole, or the cutting body may be remarkably increased to break the drill body.

Further, in the drill disclosed in Patent Document 2, a chip discharge groove that twists toward the rear side in the drill rotation direction is formed from the front end to the rear end of the drill body, and the front of the chip discharge groove in the drill rotation direction is formed. The open end working blade is provided at the rear end portion of the drill body in the wall surface facing the side.
In the drill having such a configuration, the chips are guided to the rear end side of the drill body by the twist of the chip discharge groove, and the open end machining blade is brought into contact with the open end machining blade. There was a risk of chipping or premature wear. In addition, since the open end processing blade is disposed in the twisted chip discharge groove, a step is generated between the open end processing blade and the chip discharge groove, and the chip is locked to this step, and the periphery of the open end There was a risk of hurting.

  The present invention has been made in view of such circumstances, and is a drill capable of facilitating cutting by promoting chip discharge and preventing contact between the chip and the open end working blade. The purpose is to provide.

  In order to solve such a problem, the present invention is provided with a drill blade for forming a machining hole with respect to a material to be cut at the tip of a drill body rotated about an axis, and the drill body from the drill blade. A drill provided with an open end processing blade for processing the open end of the processing hole at a position spaced apart on the rear end side, wherein the drill main body has a drill according to the direction from the front end of the drill main body toward the rear end. At least one first chip discharge groove that twists toward the rear side in the rotation direction, and the rear end side of the first chip discharge groove, the drill rotation direction from the wall facing the front side in the drill rotation direction of the first chip discharge groove A second chip discharge groove that is recessed rearward and extends parallel to the axis is formed, the drill blade is disposed at a tip of the first chip discharge groove, and the open end working blade is 2 Chip discharge groove Is arranged, it is characterized in that it is disposed in a position retracted in the drill rotation direction rear side of the wall facing the drill rotation direction front side of the first chip discharging groove.

  According to the drill having this configuration, the first chip discharge groove that twists toward the rear side in the drill rotation direction as it goes toward the rear end side of the drill body is provided on the front end side of the drill body, and the front end of the first chip discharge groove Since the drill blade is disposed in the drill, the chips generated by the drill blade move to the rear side in the drill rotation direction as the drill body rotates, and are guided by the first chip discharge groove to the rear end side of the drill body. Discharged. Therefore, chips do not remain inside the machining hole, and it is possible to perform cutting work satisfactorily.

Further, a second chip discharge groove is formed on the rear end side of the first chip discharge groove. The second chip discharge groove is recessed from the wall surface facing the front side in the drill rotation direction of the first chip discharge groove to the rear side in the drill rotation direction and extends in parallel to the axis. Since the open end processing blade is disposed in the second chip discharge groove and is disposed at a position retracted rearward in the drill rotation direction from the wall surface facing the drill rotation direction front side of the first chip discharge groove, Contact between the chips generated by the drill blade and the open end working blade is suppressed, and the open end working blade can be prevented from being broken or prematurely worn.
In addition, since the second chip discharge groove is formed so as to extend parallel to the axis, the open end processing blade is disposed so as to reduce the step between the open end processing blade and the second chip discharge groove. Becomes easy. Therefore, chips are not locked and damage around the open end can be prevented.

Here, you may arrange | position the rake face of the said open end processing blade, and the wall surface which faces the drill rotation direction front side of a said 2nd chip discharge groove | channel.
In this case, since there is no step between the open end processing blade and the second chip discharge groove, even if the chip rubs over the second chip discharge groove, the chip is not locked, and troubles due to this chip may occur. Can be prevented in advance.

Further, a sub-groove that is recessed by one step may be formed in at least a part of the first chip discharge groove.
In this case, the size of the first chip discharge groove is further increased, and chips can be discharged smoothly.

Moreover, it is preferable to set the twist angle α of the first chip discharge groove with respect to the axis within a range of 5 ° ≦ α ≦ 20 °.
In this case, by setting the twist angle α to 5 ° or more, the chips can be reliably discharged to the drill body rear end side along the first chip discharge groove. Further, by setting the twist angle α to 20 ° or less, the portion where the drill body is notched is reduced, and the rigidity of the drill body can be ensured. The twist angle α of the first chip discharge groove may be changed from the drill body front end side to the rear end side.

Moreover, it is preferable to set the core thickness W of the drill main body within a range of 0.2 × D ≦ W ≦ 0.4 × D with respect to the drill outer diameter D.
In this case, the rigidity of the drill body can be secured by setting the core thickness W to 0.2 × D or more with respect to the drill outer diameter D. In addition, by setting the core thickness W to 0.4 × D or less, the size of the first chip discharge groove can be ensured, and chip discharge can be promoted.

  ADVANTAGE OF THE INVENTION According to this invention, while discharging chip | tip, it can prevent the contact with a chip | tip and an open end processing blade, and can provide the drill which can perform cutting favorably.

Hereinafter, a drill according to an embodiment of the present invention will be described with reference to the accompanying drawings. 1 to 6 show a drill which is an embodiment of the present invention.
As shown in FIGS. 1 to 4, this drill includes a drill body 10 having a substantially multi-stage cylindrical shape that is rotated around an axis O.

At the rear end portion (upper side in FIG. 1) of the drill body 10, a mounting shaft portion 11 for mounting on the spindle end of the machine tool or the like is provided. A notch surface 11A is formed in the mounting shaft part 11, and the circumferential alignment between the drill body 10 and the main shaft end is performed by the notch surface 11A.
On the distal end side of the drill body 10 of the mounting shaft portion 11, a flange portion 12 projecting outward in the radial direction, and the diameter gradually decreases toward the distal end side of the drill body 10 connected to the distal end of the flange portion 12. The tapered end portion 13, the open end processed portion 14 that is continuous with the tip of the tapered portion 13 and extends along the axis O, and the open end processed portion 14 that is continuous with the distal end of the open end processed portion 14 has a substantially cylindrical shape. A hole processing portion 15 is provided.

A pair of first chip discharge grooves 20, 20 that twist toward the rear side in the drill rotation direction T as the drill body 10 heads from the front end to the rear end is formed. As shown in FIG. 2, the pair of first chip discharge grooves 20 and 20 are disposed 180 degrees rotationally symmetrically about the axis O. As shown in FIG. 3, the angle formed by the first chip discharge groove 20 and the axis O, the so-called twist angle α, is set within a range of 5 ° ≦ α ≦ 20 °, and more specifically α = The angle is 10 °.
First mounting seats 21 and 21 for mounting a cutting insert 25 provided with a cutting blade 27 serving as a drill blade 22 are respectively provided on the wall surface 20A facing the front side of the drill rotation direction T at the tip of the first chip discharge groove 20. Is provided.

  Here, in the present embodiment, the first mounting seat 21 provided in one first chip discharge groove 20 is positioned outward in the radial direction of the drill body 10 and provided in the other first chip discharge groove 20. The first mounting seat 21 is located inward of the drill body 10 in the radial direction. Further, a sub-groove that is recessed by one step toward the rear side of the drill rotation direction T on the rear end side of the drill body 10 with respect to the first mounting seat 21 of the wall surface 20A facing the front side of the drill rotation direction T of the first chip discharge groove 20. 23 is provided. Furthermore, as shown in FIG. 5, a sub-groove 23 that is recessed by one step toward the front side of the drill rotation direction T is also provided on the wall surface of the first chip discharge groove 20 facing the rear side of the drill rotation direction T. As shown in FIG. 5 in the cross section perpendicular to the axis O of the drilled portion 15, the core thickness W of the drill is in a range of 0.2 × D ≦ W ≦ 0.4 × D with respect to the drill outer diameter D. More specifically, W = 0.3 × D.

  On the rear end side of the drill main body 10 of the pair of first chip discharge grooves 20, 20, second chip discharge grooves 30, 30 extending in parallel with the axis O are connected. The second chip discharge groove 30 is formed so as to extend from the rear end portion of the hole processing portion 15 to the rear end portion of the taper portion 13, and is rounded up in the radial direction of the drill body 10 at the rear end of the taper portion 13. ing. As shown in FIG. 2, the pair of second chip discharge grooves 30, 30 are also disposed 180 degrees rotationally symmetrical about the axis O.

The wall surface 30A facing the front side of the drill rotation direction T of the second chip discharge groove 30 is drilled more than the wall surface 20A facing the front side of the drill rotation direction T of the first chip discharge groove 20 as shown in FIGS. It is made to move backward in the rotational direction T.
A counterbore blade 32 for countersinking the opening end of the machining hole in a portion of the wall surface 30A facing the front side of the drill rotation direction T of the second chip discharge groove 30 at the tip of the opening end machining portion 14; A second mounting seat 31 to which the cutting insert 35 to be mounted is mounted is provided.

The second mounting seat 31 is recessed from the wall surface 30A facing the front side of the drill rotation direction T of the second chip discharge groove 30 further toward the rear side of the first-stage drill rotation direction T, so It is provided so as to open outward in the direction. Note that the second mounting seat 31 and the first mounting seat 21 are disposed at different positions in the circumferential direction of the drill body 10 when viewed from the distal end side of the axis O.
In the present embodiment, as shown in FIG. 6 when viewed from the direction along the wall surface 30 </ b> A facing the front side of the drill rotation direction T of the second chip discharge groove 30, the second mounting seat 31 includes the first chip discharge groove 20. The drill body 10 is positioned on the tip side of the drill body 10 with respect to the extension line L of the wall surface 20A facing the front side of the drill rotation direction T.

  The drill body 10 has a coolant hole 16 extending along the axis O, and a plurality of coolant discharge holes 17 communicating with the coolant hole 16 and opened to the first mounting seat 21 and the second mounting seat 31, respectively. And are formed.

  The cutting insert 25 attached to the first mounting seat 21 has a substantially parallelogram flat plate shape, and one parallelogram surface serves as a rake face 26, and a cutting edge 27 is provided on a side ridge portion of the rake face 26. Is provided. The cutting inserts 25 are attached to the first mounting seats 21 and 21, respectively, and the cutting blades 27 and 27 protruding from the distal end side of the drill main body 10 are connected to the drill main body 10 from the axis O in a rotation locus around the axis O. It arrange | positions so that it may continue to an outer periphery end.

  Further, the cutting insert 35 attached to the second mounting seat 31 has a substantially square flat plate shape (or parallelogram flat plate shape), and one square surface (parallelogram surface) serves as a rake face 36. A cutting edge 37 is provided at the edge of the rake face 36. One corner portion of the cutting insert 35 is disposed so as to be located on the outer side in the radial direction of the drill body 10 with respect to the hole processing portion 15. In addition, the thickness of the cutting insert 35 is the same as the dent amount from the wall surface 30A facing the front side of the drill rotation direction T of the second chip discharge groove 30 of the second mounting seat 31, and the cutting insert 35 is attached. The rake face 36 and the wall surface 30 </ b> A facing the front side in the drill rotation direction T of the second chip discharge groove 30 are configured to be flush with each other.

  The drill constructed in this manner is attached to the first mounting seat 21 by the mounting shaft 11 being held at the spindle end of a machine tool (not shown), rotated around the axis O and fed in the direction of the axis O. A machining hole is formed in the material to be cut by the cutting blade 27 (drilling blade 22) of the cutting insert 25, and machining is performed by the cutting blade 37 (counterbore blade 32) of the cutting insert 35 attached to the second mounting seat 31. A counterbore hole having a diameter larger than that of the processed hole is formed at the opening end of the hole. In this cutting process, the coolant supplied from the machine tool is directed to the cutting inserts 25 and 35 attached to the first mounting seat 21 and the second mounting seat 31 through the coolant hole 16 and the coolant discharge hole 17. Discharged.

  According to the drill of this embodiment, the first chip discharge groove that twists toward the rear side of the drill main body 10 toward the rear end side of the drill main body 10 toward the rear side of the drill rotation direction T in the hole processing portion 15 located on the front end side of the drill main body 10. 20 is formed, and a first mounting seat 21 is provided on a wall surface 20A facing the front side of the drill rotation direction T at the tip of the first chip discharge groove 20, and a cutting blade 27 serving as a drill blade 22 is provided on the first mounting seat 21. Since the provided cutting insert 25 is attached, chips generated by the cutting edge 27 (drilling blade 22) of the cutting insert 25 attached to the first mounting seat 21 are rotated in the drill rotation direction T as the drill body 10 rotates. It moves to the rear side, is guided by the first chip discharge groove 20, and is discharged to the rear end side of the drill body 10. For this reason, the chips do not remain inside the machining hole, and the cutting can be performed satisfactorily.

  In the present embodiment, the radial positions of the first mounting seat 21 provided in one first chip discharge groove 20 and the first mounting seat 21 provided in the other first mounting seat 21 are shifted from each other. Among the cutting edges 27 of the cutting insert 25 attached to the first mounting seat 21, the cutting edges 27 protruding from the tip end side of the drill body 10 are drilled from the axis O in a rotation locus centering on the axis O. Since it arrange | positions so that it may continue to the outer periphery end of the main body 10, it can drill a to-be-cut material with these two cutting inserts 25 and 25. FIG.

  In addition, the rear end of the first chip discharge groove 20 on the rear end side of the drill main body 10 extends in parallel with the axis O and the rear side of the first chip rotation direction T from the wall surface 20A facing the front side of the drill rotation direction T of the first chip discharge groove 20. The second chip discharge groove 30 is formed so as to recede to the wall, and a second mounting seat 31 is provided on the wall surface 30 </ b> A facing the front side of the drill rotation direction T of the second chip discharge groove 30. Since the cutting insert 35 provided with the cutting edge 37 which becomes the blade 32 is attached, the chips generated by the cutting edge 27 (drilling blade 22) of the cutting insert 25 attached to the first attachment seat 21 are the second attachment. The cutting insert 35 attached to the seat 31 is discharged from the machining hole without rubbing the cutting blade 37 (counterbore blade 32).

  Furthermore, in this embodiment, as shown in FIG. 6 when viewed from the direction along the wall surface 30A facing the front side of the drill rotation direction T of the second chip discharge groove 30, the second mounting seat 31 is configured to discharge the first chip. Since the drill 20 is positioned on the tip end side of the drill body 10 with respect to the extended line L of the wall surface 20A facing the front side in the drill rotation direction T, the chips guided by the first chip discharge groove 20 enter the second mounting seat 31. Contact with the attached cutting insert 35 can be more reliably prevented. As a result, it is possible to prevent the cutting edge 37 that is the counterbore blade 32 from being lost or to be worn early, and to extend the life of the cutting insert 35.

Further, since the second chip discharge groove 30 is formed so as to extend in parallel to the axis O, the step between the cutting insert 35 attached to the second mounting seat 31 and the second chip discharge groove 30 is reduced. Thus, it is possible to prevent the chips from being locked.
In particular, in this embodiment, the dent amount from the wall surface 30A facing the front side of the drill rotation direction T of the second chip discharge groove 30 of the second mounting seat 31 and the thickness of the cutting insert 35 are set to be the same, and the rake face 36 is set. And the wall surface 30 </ b> A facing the front side of the drill rotation direction T of the second chip discharge groove 30 are arranged so as to be flush with each other. Is not locked. Thereby, damage around the opening end of the processed hole can be prevented.

  Further, in the present embodiment, the first chip discharging groove 20 is one step toward the rear end side of the drill body 10 toward the rear end side of the drill body 10 from the first mounting seat 21 of the wall surface 20A facing the front side of the drill rotation direction T of the first chip discharge groove 20. Since the concave groove 23 is provided, and the wall surface facing the rear side of the drill rotation direction T of the first chip discharge groove 20 is also provided with the auxiliary groove 23 recessed one step toward the front side of the drill rotation direction T. The size of the first chip discharge groove 20 is ensured, and the chips generated by the drill blade 22 can be discharged smoothly from the machining hole.

Furthermore, since the twist angle α with respect to the axis O of the first chip discharge groove 20 is set in the range of 5 ° ≦ α ≦ 20 °, more specifically, α = 10 °, the first chip discharge The chips can be reliably guided to the rear end side of the drill body 10 along the groove 20, and the rigidity of the drill body 10 can be ensured by reducing the portion where the drill body 10 is notched.
Further, the core thickness W of the drill body 10 in the hole processing portion 15 is set within the range of 0.2 × D ≦ W ≦ 0.4 × D with respect to the drill outer diameter D, and more specifically, W = Since it is set to 0.3 * D, while ensuring the rigidity of the drill main body 10, the magnitude | size of the 1st chip discharge groove | channel 20 can be ensured and chip | tip discharge can be accelerated | stimulated.

As mentioned above, although the drill which is embodiment of this invention was demonstrated, this invention is not limited to this embodiment, In the range which does not deviate from the technical idea of the invention, it can change suitably.
For example, although it has been described that a counterbore blade is provided on the rear end side of the drill body, the present invention is not limited to this, and a chamfering blade for chamfering the end portion of the processing hole is provided. May be.
Further, the shape of the insert is not limited to this embodiment, and is preferably selected as appropriate in consideration of cutting conditions and the like.
Furthermore, although it demonstrated as what provided the counterbore blade (opening edge process blade) at the rear end of a pair of 1st chip discharge groove, it is not limited to this, Of a pair of 1st chip discharge groove A counterbore blade (open end machining blade) may be provided only at one rear end of the.

It is a side schematic diagram of a drill which is an embodiment of the present invention. It is a front end view of the drill shown in FIG. FIG. 3 is a view in the direction of an arrow X in FIG. 2. It is a Y direction arrow directional view in FIG. It is VV sectional drawing in FIG. It is a Z direction arrow directional view in FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Drill main body 20 1st chip discharge groove 20A Wall surface 22 which faces the drill rotation direction front side Drill blade 23 Sub-groove 30 Second chip discharge groove 30A Wall surface 32 which faces the drill rotation direction front side Counterbore blade (open end processing blade)
36 Rake face

Claims (5)

A drill blade for forming a machining hole in the workpiece is provided at the tip of the drill body rotated about the axis, and the machining hole is opened at a position spaced from the drill blade to the drill body rear end side. A drill provided with an open end machining blade for machining an end,
The drill body is connected to at least one first chip discharge groove that twists toward the rear side in the drill rotation direction from the front end of the drill body toward the rear end, and the rear end side of the first chip discharge groove, A second chip discharge groove that is recessed from the wall surface facing the front side in the drill rotation direction of the one chip discharge groove to the rear side in the drill rotation direction and extending in parallel with the axis;
The drill blade is disposed at the tip of the first chip discharge groove,
The opening edge processing blade is disposed in the second chip discharge groove, and is disposed at a position retracted rearward in the drill rotation direction from the wall surface facing the front side in the drill rotation direction of the first chip discharge groove. A drill characterized by.   2. The drill according to claim 1, wherein a rake face of the open end machining blade and a wall surface facing the front side in the drill rotation direction of the second chip discharge groove are arranged flush with each other.   The drill according to claim 1 or 2, wherein at least a part of the first chip discharge groove is formed with a sub-groove that is recessed by one step.   The drill according to any one of claims 1 to 3, wherein a twist angle α of the first chip discharge groove with respect to the axis is set in a range of 5 ° ≦ α ≦ 20 °.   The core thickness W of the drill body is set in a range of 0.2 x D ≤ W ≤ 0.4 x D with respect to the drill outer diameter D. The drill according to any one of the above.

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