Indexable insert drill, cutting insert and drill body

Abstract

In the indexable insert drill, a cutting insert (10) having a cutting edge (14) is detachably mounted on a insert mounting seat (6) of a drill body (1). The insert mounting seat (6) is formed with a bottom surface (6a) facing the front end side of the drill body (1) and a wall surface (6b) extending toward the front end side and facing the drill rotation direction (T). The cutting insert (10) is formed with: a seating surface (15) facing the rear end side of the drill body (1) and seating on the bottom surface (6a); a contact surface (16) facing the side opposite to the drill rotation direction (T) and contacting the wall surface (6b); a convex portion (17) protruding from the front end side of the contact surface (16) toward the side opposite to the drill rotation direction (T); and a mounting hole extending from the front end back face (12) to the seating surface (15).

Description

Technical Field

[0001] The present invention relates to an indexable insert drill, a cutting insert, and a drill body of the indexable insert drill. The indexable insert drill has a insert mounting seat formed at the front end of the drill body rotating around an axis, and the cutting insert is detachably mounted on the insert mounting seat. The cutting insert is detachably mounted on the insert mounting seat of the blade-replaceable drill.

[0002] This application claims priority based on Patent Application No. 2019-50081 filed in Japan on March 18, 2019 and Patent Application No. 2020-25571 filed in Japan on February 18, 2020, and the contents of these are incorporated herein by reference. Background Art

[0003] For example, in the indexable insert drill described in Patent Document 1, a split surface extending perpendicularly to the axis and a torque transmission surface adjacent to the split surface are formed on the insert mounting seat of the drill body, and a split surface extending perpendicularly to the axis and a torque receiving surface extending from the split surface to the front end flank face and adjacent to the front end flank face are formed on the cutting insert. The cutting insert is detachably mounted on the insert mounting seat by tightening screws.

[0004] Patent Document 1: European Patent No. 2408581

[0005] However, in the indexable insert drill described in Patent Document 1, the torque bearing surface of the cutting insert is adjacent to and intersects with the front flank surface, and the contact portion between the torque bearing surface and the torque transmission surface of the drill body is exposed at the front end of the indexable insert drill. Therefore, in particular, in the case of wet cutting in which drilling is performed while supplying coolant, fine cutting powder generated by cutting is likely to become sludge together with the coolant and enter the contact portion between the torque bearing surface and the torque transmission surface from the front end side of the drill body, and the torque bearing surface and the torque transmission surface are worn due to the sludge, which may shorten the life of the drill. Summary of the invention

[0006] An object of the present invention is to prevent shortening of the life of a drill by preventing sludge from entering a contact portion between a cutting insert and an insert mounting seat from the front end side of a drill body.

[0007] A replaceable insert drill according to one aspect of the present invention comprises: a drill body having an insert mounting seat formed at a front end portion thereof and rotatable about an axis; and a cutting insert detachably mounted to the insert mounting seat.

[0008] A main body chip groove is formed on the outer periphery of the front end portion of the drill body, the main body chip groove opens at the front end surface of the drill body and extends to the rear end side of the drill body, and an insert chip groove is formed on the cutting insert, the insert chip groove opens at the front end back surface of the cutting insert and is connected to the main body chip groove.

[0009] A cutting edge is formed on the intersecting ridge of the wall surface of the above-mentioned blade chip groove facing the direction of rotation of the drill bit and the above-mentioned front end back cutting edge, and the above-mentioned blade mounting seat is formed with: a bottom surface facing the front end side of the above-mentioned drill bit body; a wall surface extending toward the front end side of the above-mentioned drill bit body and facing the direction of rotation of the drill bit relative to the bottom surface; and a screw hole opening in the above-mentioned bottom surface.

[0010] The cutting insert is formed with: a seating surface facing the rear end side of the drill body and seating on the bottom surface; a contact surface facing the side opposite to the drill rotation direction and contacting the wall surface from the drill rotation direction; a convex portion protruding from the front end side of the contact surface to the side opposite to the drill rotation direction; and a mounting hole penetrating from the front end back face to the seating surface. The cutting insert is mounted on the insert mounting seat by screwing a clamping screw inserted into the mounting hole into the screw hole.

[0011] In the above-mentioned indexable insert drill, when the cutting insert is mounted on the insert mounting seat, the front end of the contact area between the contact surface and the wall surface is covered by a convex portion, and the convex portion protrudes from the front end side of the contact surface to the side opposite to the drill rotation direction. That is, the convex portion protruding further to the side opposite to the drill rotation direction than the contact surface blocks the front end of the contact interface between the contact surface and the wall surface. Thus, foreign matter such as sludge can be prevented from entering from the front end of the contact area between the contact surface and the wall surface.

[0012] The cutting insert of the present invention is mounted on the above-mentioned insert mounting seat of the above-mentioned drill body of the above-mentioned blade-replaceable drill in a manner that allows it to be loaded and unloaded, and the cutting insert is formed with a blade chip groove, the above-mentioned blade chip groove is opened at the front end back cutting surface of the blade body and is connected to the above-mentioned body chip groove, and a cutting edge is formed at the intersection ridgeline portion of the wall surface of the blade chip groove facing the direction of rotation of the drill and the above-mentioned front end back cutting surface. The above-mentioned cutting insert is formed with: a seating surface facing the rear end side of the above-mentioned drill body and seating on the above-mentioned bottom surface of the above-mentioned blade mounting seat; a contact surface facing the side opposite to the drill rotation direction and contacting the above-mentioned wall surface of the above-mentioned blade mounting seat from the direction of rotation of the drill; a convex portion protruding at the front end side of the contact surface more toward the side opposite to the drill rotation direction than the above-mentioned contact surface; and a mounting hole penetrating from the above-mentioned front end back cutting surface to the above-mentioned seating surface.

[0013] The drill body of the present invention is a drill body in the above-mentioned indexable insert drill, wherein a blade mounting seat is formed at the front end of the drill body, and a body chip removal groove is formed on the outer periphery of the front end of the drill body, and the body chip removal groove opens at the front end surface of the drill body and extends to the rear end side, and the blade mounting seat is formed with: a bottom surface facing the front end side; a wall surface extending toward the front end side relative to the bottom surface and facing the direction of rotation of the drill; and a screw hole opening at the bottom surface and into which the clamping screw is screwed.

[0014] In the above-mentioned indexable insert drill, cutting insert and drill body, a convex portion protruding further toward the side opposite to the drill rotation direction than the above-mentioned abutting surface (torque receiving surface) abutting against the above-mentioned wall surface (torque transmission surface) of the insert mounting seat from the drill rotation direction toward the side opposite to the drill rotation direction of the cutting insert is formed, and the above-mentioned abutting surface of the cutting insert is not adjacent to and is not continuous with the front end back face. When the cutting insert is mounted on the insert mounting seat, the above-mentioned convex portion is arranged on the front end side of the abutting portion between the abutting surface and the wall surface, whereby the abutting portion is covered by the above-mentioned convex portion, and therefore the abutting portion between the abutting surface of these cutting inserts and the wall surface of the insert mounting seat is not exposed to the front end portion of the indexable insert drill.

[0015] Therefore, even in the case of wet cutting in which drilling is performed while supplying coolant, it is possible to prevent fine cutting powder generated by cutting from becoming sludge together with the coolant and entering the contact area between the contact surface of the cutting insert and the wall surface of the insert mounting seat from the front end side of the drill body, thereby preventing the contact surface and the wall surface from being worn due to such sludge. Therefore, according to the indexable insert drill, cutting insert, and drill body having the above-described structure, it is possible to prevent the drill life from being shortened due to such wear, thereby enabling stable drilling for a long time.

[0016] However, in such an indexable insert drill, if the cutting edge is worn and becomes blunt during such a long period of drilling, the front end flank of the cutting insert is reground, and sometimes a new cutting edge is ground at the intersection of the reground front end flank and the wall of the insert chip groove facing the drill rotation direction. At this time, the convex portion is formed with a side surface adjacent to the front end flank facing the side opposite to the drill rotation direction, so by confirming the width of the side surface in the axial direction, it can be confirmed with the naked eye whether it can be reground.

[0017] Furthermore, in the indexable insert drill described in Patent Document 1, a shaft portion is formed on the dividing surface of the cutting insert, and a hole portion is formed on the dividing surface of the insert mounting seat, and the shaft portion is inserted into the hole portion. However, the hole portion is a circular hole with a continuous inner circumference. If the hole portion is a blind hole that does not penetrate the drill body and the difference between the inner diameter of the hole portion and the outer diameter of the shaft portion of the cutting insert is small, the air in the hole portion is compressed when the shaft portion is inserted, and a force that ejects the cutting insert is exerted due to the pressure.

[0018] Therefore, in the above-mentioned structure of the indexable insert drill, it is desired to form an axial portion centered on the above-mentioned axis on one of the seating surface of the above-mentioned cutting insert and the bottom surface of the above-mentioned insert mounting seat, and to form a hole portion centered on the above-mentioned axis in which the above-mentioned axial portion can be embedded on the other surface, and the above-mentioned hole portion opens in the above-mentioned main body chip groove or the above-mentioned insert chip groove.

[0019] Thus, in the case where the hole is a blind hole having a bottom surface, even if the difference between the inner diameter of the hole and the outer diameter of the shaft is reduced, the air in the hole is discharged from the opening of the main body chip groove or the insert chip groove, so that no force to eject the cutting insert is applied. By reducing the difference between the inner diameter of the hole and the outer diameter of the shaft in this way, the runout accuracy of the cutting edge of the cutting insert can be ensured.

[0020] Furthermore, by forming the wall surface and the abutting surface so that the width in the axial direction is wider on the outer peripheral side of the drill body than on the inner peripheral side, the abutting area of ​​the abutting surface abutting against the wall surface can be ensured to be larger on the outer peripheral side of the drill body where the largest cutting load is applied during drilling. Therefore, the stress of the insert mounting seat acting on the outermost periphery of the drill body can be reduced.

[0021] At the corner where the bottom surface of the insert mounting seat intersects the wall surface, a recessed portion is formed from the main body chip groove to the outer peripheral surface of the drill body, which is recessed relative to the bottom surface and the wall surface. This can prevent the installation stability of the cutting insert from being impaired due to interference between the intersection ridge portion of the seating surface and the abutment surface of the cutting insert and the corner where the bottom surface and the wall surface of the insert mounting seat intersect.

[0022] When such a recess is formed, the cross-sectional area of ​​the recess is set so that the opening on the outer peripheral surface side of the drill body is larger than the opening on the chip groove side of the body, thereby alleviating the stress concentration on the recess on the outer peripheral surface side of the drill body, which acts on the largest cutting load during drilling, as described above. On the other hand, the cross-sectional area of ​​the opening on the chip groove side of the body is smaller, so the rigidity of the convex wall portion of the drill body forming the wall surface is not impaired.

[0023] By chamfering the intersecting ridges between the wall surface and the inner peripheral surface of the main body chip discharge groove, scratches can be prevented compared to a case where the intersecting ridges are sharp.

[0024] As described above, according to the present invention, even in wet cutting in which drilling is performed while supplying coolant, it is possible to prevent cutting powder from becoming sludge together with the coolant and from entering the abutment area between the abutment surface of the cutting insert and the wall surface of the insert mounting seat from the front end side of the drill body, thereby preventing wear from occurring on these abutment surfaces and wall surfaces, thereby enabling stable drilling to be performed for a long period of time. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 It is a perspective view showing a first embodiment of the indexable insert drill according to the present invention.

[0026] Figure 2 Observe from another direction Figure 1 A perspective view of the embodiment shown.

[0027] Figure 3 yes Figure 1 Front view of the embodiment shown.

[0028] Figure 4 is from Figure 3 Observe in the direction of arrow A Figure 1 Side view of the embodiment shown.

[0029] Figure 5 is from Figure 3 Observe in the direction of arrow B Figure 1 Side view of the embodiment shown.

[0030] Figure 6 is from Figure 3 Observe in the direction of arrow C Figure 1 Side view of the embodiment shown.

[0031] Figure 7 yes Figure 1 Exploded view of the embodiment shown.

[0032] Figure 8 It is a front view showing a first embodiment of the drill body according to the present invention.

[0033] Fig. 9 Observed from the direction of arrow A Figure 8 Side view of the embodiment shown.

[0034] Fig.10 It is a perspective view showing a first embodiment of the cutting insert according to the present invention.

[0035] Fig.11 Observe from another direction Fig.10 A perspective view of the embodiment shown.

[0036] Fig.12 yes Fig.10 Front view of the embodiment shown.

[0037] Fig.13 is from Fig.12 Observe in the direction of arrow A Fig.10 Side view of the embodiment shown.

[0038] Fig.14 is from Fig.12 Observe in the direction of arrow B Fig.10 Side view of the embodiment shown.

[0039] Fig.15 It is a perspective view showing a second embodiment of the indexable insert drill according to the present invention.

[0040] Fig.16 Observe from another direction Fig.15 A perspective view of the embodiment shown.

[0041] Fig.17 yes Fig.15 Front view of the embodiment shown.

[0042] Fig.18 is from Fig.16 Observe in the direction of arrow A Fig.15 Side view of the embodiment shown.

[0043] Fig.19 is from Fig.16 Observe in the direction of arrow B Fig.15 Side view of the embodiment shown.

[0044] Fig. 20 is from Fig.16 Observe in the direction of arrow C Fig.15 Side view of the embodiment shown.

[0045] Fig.21 yes Fig.15 Exploded view of the embodiment shown.

[0046] Fig. 22 It is a front view showing a second embodiment of the drill body according to the present invention.

[0047] Fig.23 Observed from the direction of arrow A Fig. 22 Side view of the embodiment shown.

[0048] Fig.24 Observed from the direction of arrow B Fig. 22 Side view of the embodiment shown.

[0049] Fig.25It is a perspective view showing a second embodiment of the cutting insert according to the present invention.

[0050] Fig.26 Observe from another direction Fig.25 A perspective view of the embodiment shown.

[0051] Fig. 27 yes Fig.25 Front view of the embodiment shown.

[0052] Fig.28 is from Fig. 27 Observe in the direction of arrow A Fig.25 Side view of the embodiment shown.

[0053] Fig.29 is from Fig. 27 Observe in the direction of arrow B Fig.25 Side view of the embodiment shown.

[0054] Fig.30 is from Fig. 27 Observe in the direction of arrow C Fig.25 Side view of the embodiment shown.

[0055] Fig.31 It is cut along the axis of the cutting blade and the drill body. Fig.15 An exploded sectional view of the embodiment shown. DETAILED DESCRIPTION

[0056] Figure 1 to Figure 6 A first embodiment of the indexable insert drill according to the present invention is shown. Figure 7 An exploded view of the indexable insert drill according to the first embodiment is shown. Figure 8 and Fig. 9 A first embodiment of a drill body used in an indexable insert drill according to a first embodiment is shown. Figure 10 to Figure 14 A first embodiment of a cutting insert detachably mounted on the drill body is shown.

[0057] The drill body 1 is formed of a metal material such as steel into a multi-stage cylindrical shape centered on the axis O. The rear end portion of the drill body 1 (at Figure 1 , Figure 2 , Figures 4 to 7 and Fig. 9 The right part in the middle) is a large diameter handle 2, and the front end (at Figure 1 , Figure 2 , Figures 4 to 7 and Fig. 9The left side portion in the middle is a cutting edge portion 3 of a blade body 11 to which a cutting blade 10 is detachably mounted. In the present specification, unless otherwise defined, "front end side" refers to the front end side of the drill body 1, and "rear end side" refers to the rear end side of the drill body 1. The diameter of the cutting edge portion 3 is smaller than the diameter of the shank portion 2, and a flange portion 4 is formed between the shank portion 2 and the cutting edge portion 3. The flange portion 4 is further enlarged in diameter toward the front end side compared to the shank portion 2, and then is reduced in diameter to be the same as the diameter of the cutting edge portion 3.

[0058] In this indexable insert drill, the shank 2 of the drill body 1 is held by the spindle of a machine tool, and is fed toward the front end side in the direction of the axis O while rotating in the drill rotation direction T around the axis O, thereby drilling the workpiece using the cutting edge of the cutting insert 10. On the outer peripheral surface of the shank 2, a flat surface 2a extending parallel to the axis O is formed at a distance between the front end and the rear end of the shank 2, and a flat surface 4a parallel to the flat surface 2a is also formed on the portion of the flange 4 that is enlarged in diameter relative to the shank 2.

[0059] A plurality of main body chip removal grooves 5 are formed at intervals in the circumferential direction from the front end of the cutting edge portion 3 to the leading edge of the rear end of the flange portion 4 on the outer periphery of the drill body 1. In the present embodiment, two main body chip removal grooves 5 are formed at equal intervals in the circumferential direction, and these main body chip removal grooves 5 are in a spiral shape that is gently twisted around the axis O toward the side opposite to the drill rotation direction T as it moves toward the rear end side of the drill body 1.

[0060] A blade mounting seat 6 is formed at the front end of the cutting edge portion 3. Figure 5 , Figure 7 and Figure 8 As shown in FIG. 1 , the insert seat 6 is formed by cutting off the central portion of the front end of the cutting edge portion 3 in a rectangular shape when viewed from a direction perpendicular to the axis O. Figure 8 As shown, the cut-away area extends in the radial direction relative to the axis O and reaches from one of the main body chip flutes 5 to the other main body chip flutes 5. The width of the cut-away rectangular area is from the wall surface of each main body chip flute 5 facing the drill rotation direction T to the wall surface facing the side opposite to the drill rotation direction T. Regarding the cut-away area, when viewed from a direction perpendicular to the axis O, the depth in the axis O direction is smaller than the width in the radial direction, and the area is flat.

[0061] like Figure 8As shown in the figure, the insert mounting seat 6 includes: a bottom surface 6a extending in a direction perpendicular to the axis O and facing the front end side of the drill body 1; and two wall surfaces 6b extending from both sides of the bottom surface 6a perpendicular to the bottom surface 6a and parallel to the axis O and facing the drill rotation direction T. The wall surfaces 6b are opposite to each other and parallel to each other. In the present embodiment, each of these wall surfaces 6b is a rectangle having a length direction in the radial direction relative to the axis O.

[0062] In the present embodiment, a hole portion 6c is formed in a manner extending toward the rear end side of the drill body 1, the hole portion 6c is opened at the center of the bottom surface 6a, and is in a circular cross-section with a constant inner diameter centered on the axis O. The inner diameter of the hole portion 6c is larger than the diameter of an imaginary circle inscribed in the bottom surface of the main body chip flute 5 facing the outer peripheral side of the drill body 1 in a cross section orthogonal to the axis O. Therefore, both sides of the hole portion 6c are opened in rectangular shapes at the bottom surface of each main body chip flute 5, and the bottom surface 6a of the insert mounting seat 6 is divided into two parts that are rotationally symmetrical at 180° centered on the axis O by the hole portion 6c. The hole portion 6c is a blind hole having a bottom surface facing the front end side of the drill body 1.

[0063] The bottom surface 6a divided into two by the hole portion 6c is formed with a screw hole 6d having a center at an equal distance from the axis O at a distance from the hole portion 6c. A cooling hole 1a is formed in the drill body 1 from the rear end surface of the shank 2 along the axis O toward the front end side, and the cooling hole 1a is branched into two in front of the insert mounting seat 6, and each front end is opened in the wall surface of the main body chip groove 5 facing the side opposite to the drill rotation direction T.

[0064] A convex wall portion 7 is left on the side of the wall surface 6b of the insert mounting seat 6 opposite to the drill bit rotation direction T. The convex wall portion 7 is surrounded by the wall surface 6b, the outer peripheral surface of the cutting edge portion 3 and the wall surface of the main body chip removal groove 5 facing the side opposite to the drill bit rotation direction T. The front end surface 7a of the convex wall portion 7 is a plane perpendicular to the axis O. In this embodiment, as Figure 8 and Fig. 9 As shown, a recessed portion 6e is formed as a tool retracting portion at the corner where the bottom surface 6a and the wall surface 6b intersect, and the recessed portion 6e is a circular cross-section with a constant inner diameter and is recessed relative to the bottom surface 6a and the wall surface 6b. The recessed portion 6e is used to avoid interference between the bottom surface 6a and the wall surface 6b of the insert mounting seat 6 and the cutting insert 10. Moreover, the insert mounting seat 6 and the two main body chip removal grooves 5 are respectively 180° rotationally symmetrical about the axis O.

[0065] like Figure 10 to Figure 14As shown, the cutting insert 10 detachably mounted on the insert mounting seat 6 has a insert body 11 formed of a hard material such as cemented carbide having a higher hardness than the drill body 1. The insert body 11 has a shape that is 180° rotationally symmetrical about the axis O of the drill body 1 when mounted on the insert mounting seat 6.

[0066] The insert body 11, when mounted on the insert mounting seat 6, is formed with a front end flank 12 facing the front end side of the drill body 1 and an insert chip groove 13 opened on the front end flank 12 and connected to the two main body chip grooves 5, respectively, and a cutting edge 14 is formed at the intersection of the wall surface of the insert chip groove 13 facing the drill rotation direction T and the front end flank 12. The front end flank 12 is inclined toward the rear end side of the drill body 1 as it faces the side opposite to the drill rotation direction T and the outer peripheral side of the drill body 1, thereby giving the cutting edge 14 a clearance angle and a drill taper angle.

[0067] like Fig.13 and Fig.14 As shown, in the state of being installed in the insert mounting seat 6, the rear end face of the insert body 11 is a plane perpendicular to the axis O, and is a seating surface 15 facing the rear end side of the drill body 1 and seated on the above-mentioned bottom surface 6a of the insert mounting seat 6. In the central part of the seating surface 15, a multi-stage cylindrical shaft portion 15a is formed in a manner protruding toward the rear end side, with the axis O as the center and the front end portion having a large diameter and the rear end portion having a slightly smaller diameter. The outer diameter of the front end portion of the shaft portion 15a is a size that can be inserted into the above-mentioned hole portion 6c of the insert mounting seat 6.

[0068] Furthermore, abutment surfaces 16 are formed from the wall surfaces of the two blade chip removal grooves 13 facing the side opposite to the drill rotation direction T to the outer peripheral surface of the blade body 11, and the abutment surfaces 16 abut against the above-mentioned wall surface 6b of the blade mounting seat 6 from the drill rotation direction T facing the side opposite to the drill rotation direction T. These abutment surfaces 16 are formed to be parallel to the axis O while perpendicularly intersecting the seating surface 15, and these abutment surfaces 16 also extend parallel to each other. The abutment surface 16 of this embodiment is a rectangular having a length direction in the radial direction relative to the axis O.

[0069] Two mounting holes 11a are formed in the blade body 11 at intervals from the shaft portion 15a, extending from the front flank surface 12 to the seat surface 15. These mounting holes 11a are arranged so as to be coaxial with the two screw holes 6d of the blade mounting seat 6 when the abutting surface 16 abuts against the wall surface 6b of the blade mounting seat 6. Fig.12 As shown, the inner diameter of the mounting hole 11 a gradually decreases from the opening portion on the front flank 12 side toward the seating surface 15 side, and is constant on the seating surface 15 side.

[0070] like Fig.10 and Fig.11 As shown, a convex portion 17 is formed on the insert body 11 of the cutting insert 10, and the convex portion 17 protrudes further to the side opposite to the drill rotation direction T than the abutting surface 16 at the front end side of the abutting surface 16. Therefore, when the shaft portion 15a of the insert body 11 is inserted into the hole portion 6c of the insert mounting seat 6 and the seating surface 15 is closely attached to the bottom surface 6a, and the abutting surface 16 is abutted against the wall surface 6b, these convex portions 17 are arranged almost without gap at the front end side of the abutting portion P between the abutting surface 16 and the wall surface 6b, covering the front end of the abutting portion P. As a result, the abutting portion P between the abutting surface 16 and the wall surface 6b is blocked by the convex portion 17 almost without gap, thereby preventing foreign matter from entering from the front end.

[0071] That is, the rear end face 17a of the protrusion 17 facing the rear end side of the drill body 1 is a plane that can slide and abut against the front end face 7a of the convex wall portion 7 which is a plane perpendicular to the axis O when the seating surface 15 of the blade body 11 is in close contact with the bottom surface 6a of the blade mounting seat 6 as described above, so that the rear end face 17a of the protrusion 17 abuts against the front end face 7a of the convex wall portion 7, thereby covering the front end portion of the abutment portion P of the abutment surface 16 and the wall surface 6b by the protrusion 17.

[0072] The side surface 17b of the convex portion 17 facing the side opposite to the drill rotation direction T extends parallel to the abutment surface 16 and is adjacent to the front end flank 12, that is, the side surface 17b extends parallel to the axis O and perpendicular to the rear end surface 17a, and intersects with the front end flank 12 of the blade body 11 at a certain angle at the intersection ridge line Q. The convex portion 17 of this embodiment does not cover all the front end surfaces 7a of the convex wall portion 7 of the drill body 1, but exposes the front end surface 7a on the side opposite to the drill rotation direction T of the side surface 17b. If the front end of the abutment portion P between the abutment surface 16 and the wall surface 6b is covered by the rear end surface 17a of the convex portion 17, the effect of suppressing the entry of sludge can be obtained. However, the convex portion 17 may also cover all the front end surfaces 7a of the convex wall portion 7 of the drill body 1.

[0073] As described above, the shaft portion 15a is inserted into the hole portion 6c of the blade mounting seat 6 so that the seat surface 15 is in close contact with the bottom surface 6a and the contact surface 16 is in contact with the wall surface 6b. Figure 7 As shown, the insert body 11 of the cutting insert 10 is detachably mounted on the insert mounting seat 6 by screwing the clamp screw 18 inserted into the mounting hole 11 a from the front end side of the drill body 1 into the screw hole 6 d .

[0074] In the thus constructed indexable insert drill and cutting insert 10, a coolant such as a cutting oil is sprayed from the cooling hole 1a formed in the drill body 1, and the cutting edge 14 of the insert body 11 in the cutting insert 10 cuts the cut material to perform a hole drilling process on the cut material. At this time, a convex portion 17 is formed in the insert body 11, and the convex portion 17 protrudes to the side opposite to the drill rotation direction T compared to the abutment surface 16 at the front end side of the abutment surface 16 abutting against the wall surface 6b of the insert mounting seat 6. The convex portion 17 is arranged at the front end side of the abutment portion P between the abutment surface 16 and the wall surface 6b and covers the front end portion of the abutment portion P, so that the front end portion of the abutment portion P is blocked by the convex portion 17, and the abutment portion P is not exposed at the front end portion of the indexable insert drill.

[0075] Therefore, as described above, in wet cutting with the cutting oil sprayed, even if fine cutting powder generated by cutting becomes sludge together with the cutting oil, the sludge can be prevented from entering the contact portion P between the contact surface 16 of the cutting insert 10 and the wall surface 6b of the insert mounting seat 6 from the front end side of the drill body 1. Therefore, the contact surface 16 and the wall surface 6b can be prevented from being worn by the sludge, and the life of the indexable insert drill can be suppressed from being shortened due to the wear, so that stable drilling can be performed for a long time.

[0076] In the present embodiment, the side surface 17b is adjacent to the front end flank face 12 toward the side opposite to the drill rotation direction T, and the side surface 17b is formed on the convex portion 17 in such a manner as to intersect the front end flank face 12 at a certain angle at the intersection ridge line Q. Therefore, when the cutting edge 14 is worn and becomes blunt, when the front end flank face 12 is reground and a new cutting edge 14 is ground at the intersection ridge line portion with the wall surface of the insert chip flute 13 facing the drill rotation direction T, it is possible to visually check whether regrounding is possible by checking the width of the side surface 17b in the direction of the axis O between the intersection ridge line Q and the seating surface 15. Therefore, it is possible to avoid the situation where the convex wall portion 7 of the drill body 1 is worn due to the convex portion 17 being too thin.

[0077] In the present embodiment, the seating surface 15 in the insert body 11 of the cutting insert 10 is formed with a shaft portion 15a centered on the axis O, and a hole portion 6c capable of embedding the shaft portion 15a is formed on the bottom surface 6a of the insert mounting seat 6 centered on the axis O. Therefore, the cutting insert 10 can be accurately mounted centered on the axis O of the drill body 1, thereby ensuring the runout accuracy of the cutting edge 14.

[0078] The hole 6c opens at the main body chip groove 5 of the drill body 1, so when the shaft 15a is inserted into the hole 6c, the air in the hole 6c can be discharged, thereby preventing the air in the hole 6c from being compressed. Therefore, the pressure of the compressed air does not generate a force that pushes the blade body 11 to the front end side of the drill body 1, so according to this embodiment, the cutting blade 10 can be firmly and stably mounted on the blade mounting seat 6.

[0079] In the present embodiment, as described above, an axial portion 15a centered on the axis O is formed on the seating surface 15 of the blade body 11, and a hole portion 6c capable of embedding the axial portion 15a is formed on the bottom surface 6a of the blade mounting seat 6 with the axis O as the center. Conversely, a hole portion centered on the axis O may be formed on the seating surface 15 of the blade body 11, and an axial portion capable of embedding into the hole portion may be formed on the bottom surface 6a of the blade mounting seat 6 with the axis O as the center, and the hole portion is opened in the blade chip groove 13.

[0080] Furthermore, in the present embodiment, a cooling hole 1a is formed in the drill body 1 from the rear end face of the shank 2 along the axis O toward the front end side, so that the cooling hole 1a is branched into two in front of the insert mounting seat 6 and opens on the wall surface of the main body chip groove 5 on the side opposite to the drill rotation direction T. However, instead, two cooling holes can also be formed from the rear end face of the shank 2 through the two main body chip grooves 5 toward the front end side of the drill body 1, and these cooling holes are opened in front of the insert mounting seat 6 on the wall surface of the main body chip groove 5 on the side opposite to the drill rotation direction T.

[0081] Moreover, in the present embodiment, in the blade body 11, two mounting holes 11a extending from the front end back blade surface 12 to the seating surface 15 are arranged coaxially with the two screw holes 6d of the blade mounting seat 6 when the abutting surface 16 is abutted against the wall surface 6b of the blade mounting seat 6. However, alternatively, the two mounting holes 11a may be arranged slightly eccentrically to the side opposite to the abutting surface 16 relative to the two screw holes 6d of the blade mounting seat 6.

[0082] then, Figures 15 to 20 A second embodiment of the indexable insert drill according to the present invention is shown. Fig.21 and Fig.31 An exploded view of the indexable insert drill according to the second embodiment is shown. Figure 22 to Figure 24 The second embodiment of the drill body of the present invention of the indexable insert drill of the second embodiment is shown. Figure 25 to Figure 30 A second embodiment of the cutting insert 10 detachably mounted on the drill body is shown. Figure 1 to Figure 14The same reference numerals are used for the common parts of the first embodiment, and the description of the first embodiment is used for matters not mentioned in the following description.

[0083] In the first embodiment, the wall surface 6b of the insert mounting seat 6 facing the drill rotation direction T and the abutment surface 16 of the insert body 11 of the cutting insert 10 abutting against the wall surface 6b are rectangular, and the width of the wall surface 6b and the abutment surface 16 in the direction of the axis O is constant in the radial direction relative to the axis O. In contrast, in the second embodiment, the width of these wall surfaces 6b and the abutment surface 16 in the direction of the axis O is larger on the outer peripheral side of the drill body 1 than on the inner peripheral side.

[0084] In the second embodiment, Fig.21 , Fig.24 , Fig.29 and Fig.30 As shown, the wall surface 6 b and the contact surface 16 are formed so that the width in the direction of the axis O gradually increases from the inner peripheral side toward the outer peripheral side of the drill body 1 , and these wall surface 6 b and the contact surface 16 are formed in a substantially trapezoidal shape.

[0085] Furthermore, in the first embodiment, the recessed portion 6e formed as the tool retraction portion at the corner where the bottom surface 6a of the insert mounting seat 6 intersects the wall surface 6b is a circular cross-section with a constant inner diameter, so the cross-sectional area is constant. In contrast, in the second embodiment, the cross-sectional area of ​​the recessed portion 6e is formed so that the opening on the outer peripheral surface side of the drill body 1 is larger than the opening on the side of the main body chip groove 5.

[0086] In the second embodiment, Fig. 22 As shown, the concave portion 6e is formed by a portion having a circular cross section and a portion having a concave curved cross section having a cross-sectional area two levels larger than that of the circular portion, from the opening portion on the main body chip groove 5 side toward the opening portion on the outer peripheral surface side of the drill body 1. The length of the portion having a circular cross section opening on the main body chip groove 5 side of the concave portion 6e is the longest. Fig. 22 and Fig.23 As shown, in the second embodiment, the intersecting ridgeline of the wall surface 6b of the insert mounting seat 6 and the inner peripheral surface of the main body chip flute 5 is chamfered to form a chamfered portion 6f intersecting the wall surface 6b and the inner peripheral surface of the main body chip flute 5.

[0087] In the second embodiment of the indexable insert drill, cutting insert 10 and drill body 1, the same effects as those of the first embodiment can of course be obtained, and firstly, the width in the direction of the axis O between the wall surface 6b of the insert mounting seat 6 and the abutment surface 16 of the cutting insert 10 is set to be wider on the outer peripheral side of the drill body 1 than on the inner peripheral side, thereby ensuring that the abutment area of ​​the abutment surface 16 abutting against the wall surface 6b is larger on the outer peripheral side of the drill body 1 where the largest cutting load acts during drilling.

[0088] Therefore, the stress of the insert mounting seat 6 acting on the outermost periphery of the drill body 1 can be reduced, and the cutting insert 10 can be stably held relative to the cutting load during drilling, so that high-precision drilling can be performed. In particular, in the present embodiment, the width of the wall surface 6b and the abutting surface 16 in the direction of the axis O is formed to gradually widen from the inner peripheral side toward the outer peripheral side of the drill body 1, so that the abutting area of ​​the abutting surface 16 abutting against the wall surface 6b can be ensured to be large.

[0089] In the second embodiment, a recessed portion 6e is formed as a cutter relief portion at a corner where the bottom surface 6a and the wall surface 6b of the insert mounting seat 6 intersect, and the cross-sectional area of ​​the recessed portion 6e is formed so that the opening portion on the outer peripheral surface side of the drill body 1 is larger than the opening portion on the side of the body chip flute 5. Therefore, as described above, the stress concentration on the recessed portion 6e can be relieved on the outer peripheral surface side of the drill body 1, where the largest cutting load acts during drilling.

[0090] On the other hand, the cross-sectional area of ​​the opening on the side of the main body chip groove 5 is small, so the rigidity of the convex wall portion 7 of the drill body 1 forming the wall surface 6b is not impaired, and the cutting insert 10 is not hindered from being stabilized. In particular, in the present embodiment, the cross-sectional area of ​​the concave portion 6e is formed in a stepwise manner, and the length of the section of the circular cross-section on the side of the main body chip groove 5 is the longest, so that the rigidity of the convex wall portion 7 can be further reliably maintained. Regarding the cross-sectional shape of the concave portion 6e, the cross-sectional shape of any section may be circular or a non-circular concave curve.

[0091] As in the second embodiment, the wall surface 6b of the insert mounting seat 6 and the intersecting ridgeline portion of the inner peripheral surface of the main body chip flute 5 are chamfered to form a chamfered portion 6f intersecting with the wall surface 6b and the inner peripheral surface of the main body chip flute 5, thereby preventing scratches and notches from being generated compared to the situation where the intersecting ridgeline portion maintains a sharp edge. The chamfered portion 6f does not contact the insert body 11, but is mostly formed into a concave curved surface shape inclined in the direction of the axis O.

[0092] use Fig.31 , the shaft portion 15a and the hole portion 6c in the second embodiment are described in detail. In this embodiment, in the hole portion 6c opened on the bottom surface 6a of the insert mounting seat 6 of the drill body 1, the front end side portion is a large diameter portion 6c1 with a constant inner diameter and a circular cross section centered on the axis O and a long length in the direction of the axis O, and the rear end side portion is a small diameter portion 6c2 with a constant inner diameter slightly smaller than the large diameter portion 6c1 and a circular cross section centered on the axis O and a length in the direction of the axis O shorter than the length in the direction of the axis O of the large diameter portion. However, these large diameter portions 6c1 and small diameter portions 6c2 are cut away along the bottom surface of the main body chip removal groove 5 that opens toward the outer peripheral side of the drill body 1.

[0093] On the other hand, similarly to the first embodiment, the shaft portion 15a protruding from the seating surface 15 of the insert body 11 of the cutting insert 10 is formed into a multi-stage cylindrical shape centered on the axis O, with the front end portion being the large diameter portion 15a1 and the rear end portion being the small diameter portion 15a2 with a diameter slightly smaller than the diameter of the large diameter portion 15a1, and the length of the large diameter portion 15a1 in the direction of the axis O is longer than the length of the small diameter portion 15a2 in the direction of the axis O. However, in the shaft portion 15a, the portion forming the insert chip groove 13 is also cut away along the bottom surface of the insert chip groove 13 toward the outer peripheral side.

[0094] In the present embodiment, the outer diameter of the large diameter portion 15a1 of the shaft portion 15a is such that it can be inserted into the large diameter portion 6c1 of the hole portion 6c, thereby making it possible to coaxially mount the insert body 11 of the cutting insert 10 with high precision around the axis O of the drill body 1, thereby ensuring high runout accuracy for the cutting edge 14. In order to ensure such high runout accuracy, in the fitting level in JIS B 0401-1: 1998 (ISO 286-1: 1988), it is desirable that the shaft portion 15a is within the range of h6 to h7, and it is desirable that the hole portion 6c is within the range of H6 to H7.

[0095] The length of the entire shaft portion 15a in the direction of the axis O is slightly smaller than the length (depth) of the hole portion 6c in the direction of the axis O, and the length of the large diameter portion 15a1 of the shaft portion 15a in the direction of the axis O is also slightly smaller than the length (depth) of the large diameter portion 6c1 of the hole portion 6c in the direction of the axis O. When the shaft portion 15a is embedded in the hole portion 6c, no gap is formed between the bottom surface 6a of the insert mounting seat 6 of the drill body 1 and the seating surface 15 of the insert body 11 of the cutting insert 10. These structures are the same as in the first embodiment except that the inner diameter of the hole portion 6c is constant.

[0096] Industrial Applicability

[0097] According to the present invention, even in wet cutting in which drilling is performed while supplying coolant, it is possible to prevent cutting powder from becoming sludge together with the coolant and entering the contact area between the contact surface of the cutting insert and the wall surface of the insert mounting seat from the front end side of the drill body, thereby preventing wear from occurring on these contact surfaces and the wall surface, thereby enabling stable drilling for a long time. Thus, industrial utilization can be achieved.

[0098] Explanation of symbols

[0099] 1 Drill body

[0100] 1a Cooling holes

[0101] 5 Main body chip groove

[0102] 6 Blade mounting seat

[0103] 6a: bottom surface of blade mounting seat 6

[0104] 6b: wall surface of blade mounting seat 6

[0105] 6c hole

[0106] 6c1 Large diameter part of hole 6c

[0107] 6c2 Small diameter portion of hole 6c

[0108] 6d Screw holes

[0109] 6e recess

[0110] 6f Chamfer

[0111] 7 convex wall part

[0112] 7a Front end surface of the convex wall portion 7

[0113] 10 Cutting blades

[0114] 11 Blade body

[0115] 11a Mounting holes

[0116] 12 Front flank

[0117] 13 Insert chip groove

[0118] 14 Cutting edge

[0119] 15 Seating surface

[0120] 15a Shaft

[0121] 15a1 Large diameter part of shaft part 15a

[0122] 15a2 Small diameter portion of the shaft portion 15a

[0123] 16 Abutment surface

[0124] 17 convex part

[0125] 17a rear end surface of the projection 17

[0126] 17b: side surface of the convex portion 17 facing the side opposite to the drill rotation direction T

[0127] 18 Clamping screw

[0128] O Axis of drill body 1

[0129] T Drill bit rotation direction

[0130] P: contact area between the wall surface 6b and the contact surface 16

[0131] Q: Intersection line between the front flank 12 and the side surface 17b of the convex portion 17

Claims

1. An indexable insert drill having: A drill body, a blade mounting seat is formed at the front end of the drill body and rotates around the axis; and The cutting blade is detachably mounted on the blade mounting seat. A main body chip removal groove is formed on the outer periphery of the front end portion of the drill main body. The main body chip removal groove opens at the front end surface of the drill main body and extends toward the rear end side of the drill main body. The cutting insert is provided with a blade chip removal groove, the blade chip removal groove is opened at the front end flank of the cutting insert and communicates with the main body chip removal groove. A cutting edge is formed at the intersection of the wall surface of the chip groove of the insert facing the rotation direction of the drill and the front end relief surface. The insert mounting seat is formed with: a bottom surface facing the front end side of the drill body; a wall surface extending toward the front end side of the drill body relative to the bottom surface and facing the drill rotation direction; and a screw hole opened in the bottom surface. The cutting insert is formed with: a seating surface facing the rear end side of the drill body and seating on the bottom surface; a contact surface facing the side opposite to the drill rotation direction and contacting the wall surface from the drill rotation direction; a convex portion protruding further toward the side opposite to the drill rotation direction than the contact surface at the front end side of the contact surface; and a mounting hole penetrating from the front end back surface to the seating surface. The cutting insert is mounted on the insert mounting seat by screwing the clamping screw inserted into the mounting hole into the screw hole. A convex wall portion is provided on the side of the wall surface of the insert mounting seat opposite to the drill rotation direction, and the convex wall portion is surrounded by the wall surface, the outer peripheral surface of the drill body, and the wall surface of the main body chip groove facing the side opposite to the drill rotation direction. When viewed from the front end side of the indexable insert drill, the front end surface of the convex wall portion is partially covered by the convex portion of the cutting insert and is partially exposed on the side of the convex portion opposite to the drill rotation direction.

2. The indexable insert drill according to claim 1, wherein: The convex portion has a side surface that is adjacent to the front end relief surface and faces the side opposite to the rotation direction of the drill.

3. The indexable insert drill according to claim 1, wherein: A shaft portion centered on the axis is formed on one of the seating surface of the cutting insert and the bottom surface of the insert mounting seat, and a hole portion capable of inserting the shaft portion is formed centered on the axis on the other surface. The hole portion opens in the main body chip groove or the insert chip groove.

4. The indexable insert drill according to claim 2, wherein: A shaft portion centered on the axis is formed on one of the seating surface of the cutting insert and the bottom surface of the insert mounting seat, and a hole portion capable of inserting the shaft portion is formed centered on the axis on the other surface. The hole portion opens in the main body chip groove or the insert chip groove.

5. The indexable insert drill according to any one of claims 1 to 4, wherein: The width of the wall surface and the contact surface in the axial direction is wider on the outer peripheral side of the drill body than on the inner peripheral side.

6. The indexable insert drill according to any one of claims 1 to 4, wherein: At a corner where the bottom surface of the insert mounting seat intersects the wall surface, a recessed portion is formed from the main body chip removal groove to the outer peripheral surface of the drill body, which is recessed relative to the bottom surface and the wall surface. The cross-sectional area of ​​the recessed portion is larger at an opening portion on the outer peripheral surface side of the drill body than at an opening portion on the body chip discharge groove side.

7. The indexable insert drill according to claim 5, wherein: At a corner where the bottom surface of the insert mounting seat intersects the wall surface, a recessed portion is formed from the main body chip removal groove to the outer peripheral surface of the drill body, which is recessed relative to the bottom surface and the wall surface. The cross-sectional area of ​​the recessed portion is larger at an opening portion on the outer peripheral surface side of the drill body than at an opening portion on the body chip discharge groove side.

8. The indexable insert drill according to any one of claims 1 to 4, wherein: The intersecting ridgeline portion between the wall surface and the inner peripheral surface of the main body chip discharge groove is chamfered.

9. The indexable insert drill according to claim 5, wherein: The intersecting ridgeline portion between the wall surface and the inner peripheral surface of the main body chip discharge groove is chamfered.

10. The indexable insert drill according to claim 6, wherein: The intersecting ridgeline portion between the wall surface and the inner peripheral surface of the main body chip discharge groove is chamfered.

11. The indexable insert drill according to claim 7, wherein: The intersecting ridgeline portion between the wall surface and the inner peripheral surface of the main body chip discharge groove is chamfered.

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