JP2007130739A - Boring tool - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a boring tool capable of forming a machined hole having a small dimensional tolerance by adjusting a radial position of a cutting-blade tool body, and also, capable of simply and accurately executing positional adjustment of a cutting blade. <P>SOLUTION: A recessed part 19 is formed at the tip part of the tool body 12. A mounting seat 20 is formed at the rear side of the recessed part 19 in a tool rotating direction T. An insert 30 is mounted to the mounting seat 20. Back taper is applied on a face 32 of the insert 30 which faces the radial outside of the tool body 12. A clamp screw hole is bored in a wall face of the mounting seat 20 which faces the radial outside of the tool body 12. One adjusting screw hole 26, which stores an adjusting screw 27 for adjusting the radial position of the tool body 12 while pressing a face to be pressed of the insert 30, is provided one by one in one mounting seat 20 at the rear side of the mounting seat 20 in the tool rotating direction T. The adjusting screw hole 26 is formed at the further tip side of the tool body 12 than the clamp screw hole. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a hole machining tool that is inserted into a prepared hole that is formed in advance in a workpiece and that cuts an inner wall surface of the prepared hole.

  As this type of drilling tool, a reamer is known in which a cutting edge provided with a cutting edge is brazed to the tip of a long cylindrical tool body rotated about an axis. This reamer is rotated around the axis and fed in the axial direction, and inserted into a prepared hole formed in the work material in advance, and an inner wall surface of the prepared hole is formed at the cutting edge portion. To form a processed hole having a predetermined inner diameter.

  By the way, in the case where the blade edge portion is brazed to the tool body in this way, the position adjustment in the radial direction of the cutting blade cannot be performed, and the cutting blade position is determined by the brazing accuracy. For this reason, when the dimensional tolerance required for the processed hole formed in the workpiece is very small, it may not be possible to handle the processed hole.

  Therefore, for example, as shown in Patent Document 1, a diameter adjusting mechanism capable of detachably attaching an insert having a cutting blade to the tip of a tool body and adjusting the position of the cutting blade provided in the insert in the tool body radial direction. An insert-type reamer is provided. FIG. 7 shows an example of an insert type reamer having a conventional diameter adjusting mechanism.

  A reamer 1 shown in FIG. 7 has a long cylindrical tool body 2 that is rotated around an axis O, and an insert 4 having a cutting edge 3 is fixed to the outer periphery of the tip end of the tool body 2 by a clamp screw 5. ing. The cutting blade 3 of the insert 4 is directed to the outer side of the tool body 2 in the radial direction and the distal end side of the tool body 2, and the adjustment mechanism 6 that adjusts the position of the insert 4 on the inner side of the tool body 2 of the insert 4 in the radial direction. , Two adjusting screws 7, 8, a first adjusting screw 7 disposed on the rear end side of the tool body 2 of the insert 4 and a second adjusting screw 8 disposed on the front end side of the tool body 2, are provided. The tip surfaces of the two adjusting screws 7, 8 are in contact with the surface of the insert 4 facing inward in the tool body 2 radial direction.

In the reamer 1 having this configuration, when the position of the cutting blade 3 of the insert 4 is adjusted, the first adjusting screw 7 and the second adjusting screw 8 are used to adjust the axis O of the cutting blade 3 formed on the insert 4. When the angle of inclination (back taper) and the tool body 2 radial position can be adjusted, a machined hole with a predetermined inner diameter can be formed with good dimensional accuracy, and the dimensional tolerance required for the machined hole is small Even if there is, we can cope. Further, by appropriately attaching the back taper, unnecessary contact between the inner wall surface of the machining hole and the insert can be prevented, and cutting resistance can be reduced.
JP 2002-160125 A

  However, in the reamer 1 configured as described above, the mounting seat of the insert 4, the clamp screw hole into which the clamp screw 5 is screwed, and the adjustment screw that accommodates the two adjustment screws 7 and 8 at the tip of the tool body 2. It is necessary to form a hole, and a portion where the tool body 2 is cut out becomes large, and the rigidity of the tool body 2 is insufficient. In particular, in the case of a small-diameter reamer, there is no space for forming the mounting seat, the clamp screw hole, and the adjustment screw hole, and therefore, an insert 4 type reamer having such an adjustment mechanism 6 is provided. I could not.

  Further, since the adjustment mechanism 6 for adjusting the back taper and the adjustment mechanism 6 for adjusting the radial position of the tool body 2 are the same first and second adjustment screws 7 and 8, for example, after adjusting the back taper, the tool When adjusting the position of the main body 2 in the radial direction, the adjusted back taper may change, and it may be necessary to adjust the position again. Therefore, it takes a lot of time and labor to adjust the position of the insert 4. It was impossible to easily adjust the position.

  This invention has been made in view of the circumstances described above, and by adjusting the position of the cutting blade provided in the insert in the radial direction of the tool body, it is possible to form a machining hole with a small dimensional tolerance, An object of the present invention is to provide a drilling tool capable of easily and accurately adjusting the position of an insert.

  In order to solve this problem, the present invention is a hole machining tool that is inserted into a pilot hole formed in advance in a workpiece and cuts the inner wall surface of the pilot hole, and is rotated about an axis. A concave portion opened toward the distal end side of the tool body and the radially outer side of the tool body is formed at the distal end portion of the tool body, and a mounting seat is formed on the rear side in the tool rotation direction of the recessed portion. A flat plate-like insert having a cutting edge is attached to the seat with its thickness direction directed in the tool body radial direction, and the surface of the insert facing inward in the tool body radial direction is a seating surface. A surface facing the rear side in the tool rotation direction is a pressed surface, a surface facing the front side in the tool rotation direction of the insert is a rake surface, and the cutting edge is formed on the ridge line portion on the outer side in the tool body radial direction of the rake surface. A blade is formed and the inserter A back taper is attached to a surface of the tool body in the radial direction of the tool body so as to gradually recede toward the inner side of the tool body in the radial direction of the tool body. A clamp screw hole is formed in the wall surface facing the outer side in the main body radial direction, and the insert is mounted by screwing the clamp screw into the clamp screw hole, and on the rear side in the tool rotation direction of the mounting seat. Adjusting screw holes for accommodating adjusting screws for pressing the pressed surface of the insert and adjusting the tool body radial position of the cutting blade are provided one by one in the mounting seat, The adjustment screw hole is formed on the distal end side of the tool body with respect to the clamp screw hole.

  In the hole drilling tool with this configuration, the adjustment screws for adjusting the position of the insert are arranged one by one on one mounting seat, so it is only necessary to adjust the screwing amount of the adjustment screw to adjust the cutting edge provided in the insert. The tool body radial position can be adjusted. Here, the back taper is attached in advance when the insert is attached to the mounting seat, and when the insert is pressed with the adjusting screw, the adjusting screw is arranged on the tip side of the tool body with respect to the clamp screw. Therefore, the back taper is displaced toward the larger side. Therefore, the insert and the inner wall surface of the processed hole do not needlessly contact each other, and an increase in cutting resistance can be prevented. Thus, since the position of the cutting blade in the radial direction of the tool body may be adjusted without adjusting the back taper, the position of the cutting blade can be easily adjusted.

  Further, the insert has a flat plate shape and is attached with the thickness direction facing the tool body radial direction, and the surface facing the front side in the tool rotation direction is a rake face and the surface facing the tool body radial inner side. Since the so-called vertical blade insert with a seating surface is attached, the insert body can be attached so that the thickness direction of the insert substantially coincides with the radial direction of the tool body. The part which cuts out can be made small. In addition, since only one adjusting screw is formed on one mounting seat, the portion where the tool body is cut out can also be reduced. Therefore, even if it is a small diameter drilling tool, it can be set as the insert type drilling tool which can adjust a diameter. Therefore, the processing hole can be formed with high dimensional accuracy, and processing of a processing hole with a small dimensional tolerance can be handled.

  Here, the tool body is provided with a pair of mounting seats that are 180 ° rotationally symmetric about the axis, and from the wall surface of the one mounting seat facing the tool body in the radial direction, the other mounting seat A through hole penetrating to a wall surface facing the radially outer side of the tool body is formed, and one end side of the through hole is used as the clamp screw hole of one of the mounting seats, and the other end side of the through hole is the other mounting seat. By using the clamp screw hole, even if two mounting seats are provided, the portion of the tool body cut out can be reduced, and the rigidity of the tool body can be ensured.

  Therefore, even if it is a small diameter drilling tool, two inserts can be attached and the inner wall surface of a prepared hole can be cut smoothly. In addition, since the rigidity of the tool body is ensured, runout when the drilling tool is rotated at a high speed is prevented, and the drilled hole can be formed with high accuracy. Further, since the two inserts are arranged in a 180 ° rotational symmetry, the dynamic balance of the drilling tool can be ensured, and the deflection of the drilling tool during high-speed rotation can be reliably suppressed.

  Furthermore, as the insert, a cutting blade portion made of diamond is provided, and by using the cutting blade portion on which the cutting blade is formed, the wear resistance of the cutting blade can be improved. The life of the insert can be extended.

  As described above, according to the present invention, the position of the cutting blade provided in the insert in the radial direction of the tool body can be adjusted to form a machined hole with a small dimensional tolerance, and the position of the insert can be easily adjusted. It is possible to provide a drilling tool that can be accurately performed.

Hereinafter, a drilling tool according to an embodiment of the present invention will be described with reference to the accompanying drawings. 1 to 5 show a reamer as a drilling tool according to an embodiment of the present invention. FIG. 6 shows a cutting tool to which this reamer is attached.
The reamer 11 is provided with a long cylindrical tool body 12 centering on the axis O. The tool body 12 includes a rear member 12A made of cemented carbide and a tip member 12B made of steel. And have.

  A V-shaped groove 13 whose central portion is recessed toward the front end side is formed on the rear end surface of the distal end member 12B so that the bottom of the groove is perpendicular to the axis O and the V-shaped bisector is positioned on the axis O. Is formed. Further, on the front end surface of the rear member 12A, a convex portion 14 having a convex V-shaped cross section that can be fitted into the V-shaped groove 13 has a V-shaped ridge line orthogonal to the axis O, and is V-shaped, etc. The dividing line is formed so as to be positioned on the axis O. The tool body 12 is integrally formed by fitting and brazing the V-shaped groove 13 and the convex portion 14.

As shown in FIG. 6, a mounting portion 15 for mounting the reamer 11 to the cutting tool 40 is provided on the rear end side of the tool body 12 (the rear end side of the rear member 12A). 15 is formed with an inclined plane 16 that is inclined so as to gradually approach the axis line O toward the tip end side of the tool body 12 with respect to the axis line O.
The tool body 12 has a coolant supply hole 17 extending along the axis O and penetrating from the rear end surface to the front end surface. The coolant supply hole 17 opens at the front end surface of the front end member 12B. Yes.

  On the distal end side of the tool body 12, a recess 19 opened toward the distal end side and the radially outer side of the tool body 12 extends parallel to the axis O toward the rear end side, and has a length of the rear member 12A. It is formed to reach near the center. As shown in FIG. 5, the concave portion 19 has a concave curved shape in which a cross section perpendicular to the axis O is recessed toward the inside in the radial direction of the tool body 12. In the present embodiment, a pair of recesses 19 and 19 are formed in the tool body 12, and the pair of recesses 19 and 19 are arranged 180 degrees rotationally symmetrical about the axis O.

  And the mounting seat 20 for attaching the insert 30 which has a cutting blade is formed in the tool main body 12 front end side of this recessed part 19, and the tool rotation direction T back side. The mounting seat 20 is provided with a wall surface 21 facing the front side in the tool rotation direction T and a wall surface 22 facing the outer side in the radial direction of the tool body 12, and is orthogonal to the axis O of the portion where the mounting seat 20 is formed. As shown in FIGS. 3 and 4, the cross section is configured such that one end of the concave curve forming the concave portion 19 is continuous with the wall surface 22 facing the tool body 12 radially outward of the mounting seat 20.

  Here, in this embodiment, mounting seats 20 and 20 are formed in the respective recesses 19 and 19, that is, the tool body 12 has a pair of mounting seats 20 and 20, and the pair of mounting seats 20. , 20 are arranged 180 degrees rotationally symmetrical about the axis O. As shown in FIGS. 3 and 4, the wall surfaces 22, 22 facing the radially outer side of the tool body 12 included in the pair of mounting seats 20, 20 are arranged in parallel with the axis O therebetween. The tool body 12 is formed with one through-hole 23 that extends perpendicular to the axis O so as to open to the wall surfaces 22, 22 facing radially outward of the tool body 12. And the part opened to the wall surfaces 22 and 22 which face each tool main body 12 radial direction outer side is the clamp screw hole 24 into which the clamp screw 25 is screwed.

Further, as shown in FIG. 3, an adjustment screw hole 26 is formed on the rear side of the mounting seat 20 in the tool rotation direction T, and one end of the adjustment screw hole 26 extends to the front side of the mounting seat 20 in the tool rotation direction T. Opened to the facing wall surface 21, the other end is opened to the outer peripheral surface of the tool body 12 and the end of the other recess 19. The adjusting screw holes 26 are formed so as to extend so as to incline and intersect with the wall surface 21 facing the front side in the tool rotation direction T of the mounting seat 20. It has been. The adjustment screw hole 26 is formed on the distal end side of the tool body 12 with respect to the clamp screw hole 24.
The adjustment screw 27 screwed into the adjustment screw hole 26 has a substantially cylindrical shape, and a tapered portion 28 that gradually decreases in diameter toward the distal end side is formed at the distal end portion.

  In addition, a guide pad 29 made of a hard material and having a substantially oval plate shape as an outer shape is disposed on the outer peripheral portion on the distal end side of the tool body 12. In the present embodiment, as shown in FIGS. 4 and 5, the pair of guide pads 29, 29 are 180 ° rotationally symmetric about the axis O, and the recess 19 and the mounting seat 20 are arranged radially outside the tool body 12. It is arranged at a position of approximately 90 ° with respect to the intersection with the facing wall surface 22.

Next, the insert 30 attached to the tool body 12 will be described.
As shown in FIGS. 1 and 3, the insert 30 has a substantially rectangular flat plate shape, one surface 31 facing the thickness direction is formed in a flat shape, and the other surface 32 facing the thickness direction is formed. It is formed in a convex curved surface that is convex outward. One surface 31 facing the thickness direction is a seating surface to the mounting seat 20, and the other surface 32 facing the thickness direction is an outer peripheral flank. In the present embodiment, the curvature radius of the convex curve in the cross section perpendicular to the axis O of the convex curved surface formed by the other surface 32 facing the thickness direction is formed so as to substantially match the outer radius of the tool body 12. ing.

  An insertion hole 33 for inserting the clamp screw 25 is formed in the insert 30 so as to extend perpendicularly to one surface 31 facing the thickness direction formed in a planar shape and penetrate in the thickness direction. . A large-diameter portion 33A capable of accommodating the head portion 25A of the clamp screw 25 is formed in the opening portion on the other surface 32 side facing the thickness direction formed in the convex curved surface shape of the insertion hole 33. A tapered hole 33 </ b> B that is reduced in diameter toward one surface 31 facing the thickness direction is formed.

  One of the side faces of the insert 30 is a rake face 34, and a flat cutting edge part 35 made of a diamond sintered body is disposed on one end side of the side face part forming the rake face 34. ing. An outer peripheral blade 35 is formed at the intersecting ridge line portion of the cutting blade portion 35 with the other surface 32 facing the thickness direction, and a bottom blade 37 is formed at the ridge line portion connected to the outer peripheral blade 35, so-called vertical A blade insert 30 is provided.

  The outer peripheral blade 35 is formed so as to gradually retreat inside the insert 30 as it moves away from the bottom blade 37. In other words, the other surface 32 facing the thickness direction as viewed from the side facing the rake surface 34 is directed toward the one surface 31 gradually facing the thickness direction as the distance from the cutting edge 35 increases. It is made to approach.

  Moreover, the side part located on the opposite side of the side part made into the rake face 34 is comprised from two planes which make a convex V shape toward the outside, and is on one face 31 side facing the thickness direction. The flat surface located is the pressed surface 38, and the flat surface located on the other surface 32 side facing the thickness direction is in contact with the wall surface 21 facing the front side in the tool rotation direction T of the mounting seat 20 39.

  The insert 30 having such a configuration is attached to the mounting seat 20 of the tool body 12. One surface 31 (sitting) facing the thickness direction of the insert 30 on the wall surface 22 facing the outside of the tool body 12 in the radial direction of the tool body 12 so that the side surface portion to be the rake face 34 faces the front side in the tool rotation direction T. The insert 30 is placed so that the abutment surface 39 of the insert 30 abuts the wall surface 21 of the mounting seat 20 facing the front side in the tool rotation direction T.

  The clamp screw 25 is inserted into the insertion hole 33 of the insert 30 and is screwed into the clamp screw hole 24 opened in the wall surface 22 facing the outside of the tool body 12 in the radial direction of the mounting seat 20. Fixed to. Here, by screwing the adjusting screw 27 screwed into the adjusting screw hole 26 provided on the rear side of the mounting seat 20 in the tool rotation direction T, the taper portion 28 formed at the tip of the adjusting screw 27 is inserted into the insert 30. It comes into contact with the pressed surface 38.

By attaching the insert 30 in this manner, the bottom blade 37 is disposed toward the distal end side of the tool main body 12 and the outer peripheral blade 35 is disposed outward in the radial direction of the tool main body 12. Here, since the outer peripheral blade 35 is formed so as to gradually recede to the inner side of the insert 30 as it moves away from the bottom blade 37, the outer peripheral blade 35 has a back taper.
In the present embodiment, as shown in FIG. 3, the rake face 34 of the insert 30 has a cross section perpendicular to the axis O, the intersection 19 of the wall surface 22 facing the recess 19 and the tool body 12 in the radial direction, and the axis O. Will be arranged along a straight line connecting the two.

The reamer 11 thus configured is used by being mounted on the cutting tool 40 shown in FIG. The cutting tool 40 has a multi-stage cylindrical main body 41 that rotates about the axis M, and a mounting hole 42 that extends along the axis M is formed in the tip surface 41 A of the main body 41. A coolant hole 44 accommodating the position adjusting bolt 43 is provided on the rear end side of the main body 41 of the mounting hole 42 so as to communicate with the mounting hole 42, and one end is provided on the rear end side of the main body 41. The mounting portion 45 is opened.
Further, a fixing screw hole 46 is formed in the side surface of the main body 41 and communicated with the mounting hole 42, and a fixing screw 47 is screwed. Further, a plurality of runout adjustment screws 48 for adjusting the runout of the reamer 11 are arranged at equal intervals in the circumferential direction and perpendicular to the axis M, respectively, at the front end side of the fixing screw hole 46. The rear member 12A is screwed so as to come into contact with the outer peripheral surface.

  The reamer 11 is inserted into a mounting hole 42 formed in the distal end surface of the main body 41, and after adjusting the position of the reamer 11 in the axis M direction with the position adjusting bolt 43, the rear end surface of the tool main body 12 is positioned. The adjusting bolt 43 is placed in contact with the front end surface of the adjusting bolt 43 so that the inclined plane 16 of the mounting portion 15 faces in the direction in which the fixing screw hole 46 of the main body portion 41 is provided. Then, the position is adjusted by a plurality of shake adjusting screws 48 so that the axis O of the reamer 11 and the axis M of the main body 41 coincide with each other, and the fixing screw 47 screwed into the fixing screw hole 46 of the main body 41 is screwed in. The reamer 11 is fixed to the main body 41 by pressing the inclined plane 16.

  The cutting tool 40 to which the reamer 11 is mounted is attached to the spindle end of the machine tool via the attachment portion 45, rotated about the axis M (axis O) and at the tip of the axis M (axis O). The reamer 11 is inserted into a prepared hole formed in the workpiece, and an inner wall surface of the prepared hole is cut to form a processed hole having a predetermined inner diameter.

  In the reamer 11 having this configuration, the adjustment screws 27 for adjusting the radial position of the insert 30 are arranged one by one on the mounting seat 20, so that the insert 30 can be adjusted by adjusting the screwing amount of the adjustment screw 27. The tool body 12 radial position can be adjusted. Here, the back taper is configured to be attached in advance when the insert 30 is attached to the mounting seat 20, and the adjustment screw 27 is disposed on the distal end side of the tool body 12 with respect to the clamp screw 25. When the insert 30 is pressed with the adjusting screw 27, the back taper is displaced larger. Therefore, even if the radial position of the insert 30 is adjusted with the adjusting screw 27, the back taper is largely fluctuated and the insert 30 and the processing hole do not come into unnecessary contact. Thus, since it is only necessary to adjust the radial position of the insert 30, the position of the insert 30 can be easily adjusted.

  Furthermore, since the insert 30 of the vertical blade is attached so that one surface 31 facing the thickness direction of the insert 30 faces the inner side in the radial direction of the tool body 12 as a seating surface, a tool is formed to form the attachment seat 20. A portion where the main body 12 is cut out can be reduced. Further, since only one adjusting screw 27 is formed on one mounting seat 20, the portion where the tool body 12 is cut out can be reduced. Therefore, even if the reamer 11 has a small diameter, as the insert 30 type reamer 11 whose diameter can be adjusted, the machining hole can be formed with high dimensional accuracy, and it is possible to cope with the formation of a machining hole with a small dimensional tolerance. .

  Further, the pair of mounting seats 20 are arranged 180 ° rotationally symmetrically about the axis O, and the wall surfaces 22 of the mounting seats 20 facing the outside in the radial direction of the tool body 12 are arranged in parallel to each other. A through hole 23 is formed so as to open to the wall surface 22 facing outward in the direction and orthogonal to the axis O, and a portion opened to the wall surface 22 facing radially outward of the tool body 12 is a clamp screw hole 24. Therefore, the portion of the tool body 12 notched as the clamp screw hole 24 can be reduced, and the rigidity of the tool body 12 can be ensured. Further, these clamp screw holes 24 can be easily formed.

  By forming the mounting seat 20 in this way, the two inserts 30 can be mounted even with the small-diameter reamer 11, and the inner wall surface of the prepared hole can be cut smoothly. In addition, since the rigidity is ensured, it is possible to prevent the shake at the time of high-speed rotation and form the processed hole with high accuracy. Further, since the two inserts 30 are arranged in 180 ° rotational symmetry, the dynamic balance of the reamer 11 can be ensured, and the reamer 11 can be reliably prevented from shaking.

  Further, since the insert 30 is provided with the cutting edge portion 35 made of a diamond sintered body, the wear resistance of the outer peripheral edge 36 and the bottom edge 37 can be improved. It is possible to extend the service life.

  In addition, since the pair of guide pads 29 are disposed on the outer periphery on the tip side of the tool body 12, the reamer 11 can be prevented from shaking more reliably by sliding the inner surface of the machining hole and the guide pads 29. The processing hole can be formed with high dimensional accuracy. Further, the pair of guide pads 29 is approximately 90 degrees with respect to the intersection of the recess 19 and the wall surface 22 of the mounting seat 20 facing the outside in the radial direction of the tool body 12 about the axis O. Since it is arranged at a position of °, the dynamic balance of the reamer 11 is improved, and shake during high-speed rotation can be surely prevented.

As mentioned above, although the reamer which is embodiment of this invention was demonstrated, this invention is not limited to this, It can change suitably in the range which does not deviate from the technical idea of the invention.
For example, the reamer has been described as being used by being mounted on the cutting tool shown in FIG. 6, but is not limited thereto, and may be used by being mounted on other cutting tools or adapters. .

In addition, the insert has been described as having a cutting blade portion made of a diamond sintered body, but the insert is integrally formed of a cemented carbide alloy or has a cutting blade portion made of a cBN sintered body. But it ’s okay.
Also, the shape of the insert is not limited to this embodiment, and can be of any shape.

It is a front-end | tip part side surface enlarged view of the reamer which is embodiment of this invention. It is a bottom view of the reamer shown in FIG. It is XX sectional drawing in FIG. It is YY sectional drawing in FIG. It is ZZ sectional drawing in FIG. It is a side view of the cutting tool with which the reamer shown in FIG. 1 was mounted | worn. It is a side part enlarged view of the front-end | tip part of the conventional reamer.

Explanation of symbols

11 Reamer (Drilling tool)
12 Tool body 19 Recess 20 Mounting seat 23 Through hole 24 Clamp screw hole 25 Clamp screw 26 Adjustment screw hole 27 Adjustment screw 30 Insert 31 One surface (sitting surface) facing the thickness direction
32 The other surface facing the thickness direction (surface facing the tool body radial direction outer side)
34 Rake face 35 Cutting edge 36 Outer peripheral edge (cutting edge)
37 Bottom edge (cutting edge)
38 Pressed surface

Claims (3)

A hole machining tool that is inserted into a pilot hole formed in advance in a workpiece and cuts the inner wall surface of the pilot hole,
A concave portion opened toward the distal end side of the tool body and the radially outer side of the tool body is formed at the distal end portion of the tool body rotated around the axis, and a mounting seat is formed on the rear side in the tool rotation direction of the recessed portion. Has been
A flat plate-like insert having a cutting edge is attached to the mounting seat with its thickness direction facing the tool body radial direction, and the surface of the insert facing the tool body radial direction inside is a seating surface, The surface of the insert that faces the rear side in the tool rotation direction is a pressed surface, and the surface of the insert that faces the front side in the tool rotation direction is a rake surface. The cutting edge is formed, and the surface of the insert that faces the outer side of the tool body in the radial direction is back-tapered so as to gradually recede toward the inner side of the tool body in the radial direction as it goes toward the rear end side of the tool body. And
A clamp screw hole is formed in the wall surface of the mounting seat facing the tool body in the radial direction, the clamp screw is screwed into the clamp screw hole, the insert is mounted, and the tool of the mounting seat is mounted. On the rear side in the rotation direction, adjustment screw holes that accommodate adjustment screws for pressing the pressed surface of the insert and adjusting the tool body radial position of the cutting blade are provided one by one in the mounting seat. Is provided,
The drilling tool according to claim 1, wherein the adjustment screw hole is formed closer to the tip side of the tool body than the clamp screw hole. The tool body is provided with a pair of mounting seats that are 180 ° rotationally symmetric about the axis,
A through hole penetrating from the wall surface of the one mounting seat facing the radially outer side of the tool body to the wall surface of the other mounting seat facing the radially outer side of the tool body is formed, and one end side of the through hole is 2. The drilling tool according to claim 1, wherein the clamp screw hole of one of the mounting seats is the clamp screw hole of the other mounting seat, and the other end of the through hole is the clamp screw hole of the other mounting seat.   The said insert is provided with the cutting blade part comprised with the diamond sintered compact, The said cutting blade is formed in this cutting blade part, The Claim 1 or Claim 2 characterized by the above-mentioned. Drilling tool.

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