Cutting tools and their tool bodies and core materials

Abstract

To easily provide a coolant discharge port at a desired position without forming a complicated flow path as in the past, particularly for a drilling tool with a large diameter. [Solution] A core member 20 detachably attached to a tool body 10 of a cutting tool has a coolant groove 28 provided at the base end of the core member 20 and a coolant flow path 29 that communicates from the coolant groove 28 to the tip end of the core member 20. The tool body 10 also has a core mounting portion into which the core member 20 is incorporated, a first coolant supply path 18A for supplying coolant from the base end 10b toward the core mounting portion, and a second coolant supply path that communicates from an inner circumferential surface 11p of the core mounting portion to the tip end 10t of the tool body 10.

Description

[Technical Field]

[0001] The present invention relates to a cutting tool, a tool body and a core member thereof. [Background technology]

[0002] Conventionally, large-diameter drilling tools include tools in which an insert seat for mounting an insert that serves as a central cutting edge is integrally formed with the head, tools in which a pocket for mounting an insert that serves as a central cutting edge is a cartridge type, etc. Also known as such large-diameter drilling tools are those that have a coolant flow path provided inside them (see, for example, Patent Documents 1 to 3). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Chinese Patent No. 103909287 [Patent Document 2] U.S. Patent No. 9,498,829 [Patent Document 3] German Patent Application Publication No. 102017209442 Summary of the Invention [Problem to be solved by the invention]

[0004] However, in large-diameter drilling tools, the outer diameter of the tool is larger than the hole diameter of the coolant flow passage provided near the axial center of the tool body, so if a coolant outlet is to be provided at a desired position from the coolant flow passage provided near the axial center toward the cutting edge provided at the tip of the tool, it becomes necessary to form flow passages that branch off in a complex manner from the coolant flow passage provided near the axial center of the tool body, which tends to make the flow passages complex. For example, to branch the flow passages, it may be necessary to create holes that penetrate the outer surface of the tool, which can create problems such as the need for parts that are unnecessary for the function of the tool to seal the through holes.

[0005] Therefore, the present invention relates particularly to large-diameter drilling tools, and aims to provide a cutting tool, a tool body, and a core member thereof that make it easy to provide a coolant discharge port at a desired position without forming a complex flow path as in the past. [Means for solving the problem]

[0006] One aspect of the present invention is a core member detachable from a tool body of a cutting tool, comprising: a coolant groove provided at a base end of the core member along a central axis of the core member; a coolant flow path communicating from the coolant groove to a tip end portion of the core member; The core member has the following structure.

[0007] Such a core member is designed to allow coolant to be supplied from the base end to the tip end through a coolant flow path, making it possible to provide a coolant outlet at the desired position without forming a complex flow path as in the past.

[0008] In the core member as described above, a plurality of coolant grooves may be provided.

[0009] In the core member as described above, the inlet of the coolant flow path may be provided on the bottom surface of the coolant groove.

[0010] In the core member as described above, a plurality of coolant passages may be provided.

[0011] In the core member as described above, a pair of coolant flow paths may be provided symmetrically about the central axis.

[0012] In the core member as described above, the coolant flow passage may be configured as a flow passage that becomes more distant from the central axis as it moves from the base end to the tip end.

[0013] In the core member as described above, a spiral groove may be provided on the outer peripheral surface.

[0014] The core member as described above may be cylindrical.

[0015] In the core member as described above, an insert seat for mounting a cutting insert may be provided at the tip portion.

[0016] In the core member as described above, the insert seat may be arranged so as to surround the central axis.

[0017] The core member may be a drill.

[0018] Another aspect of the present invention is a tool body of a cutting tool to which a cutting insert and a drill can be removably attached, comprising: a core mounting portion into which a core member having a cutting edge is mounted along a central axis of the tool body; a first coolant supply passage for supplying coolant from a base end side toward the core mounting portion; a second coolant supply passage communicating from the inner circumferential surface of the core mounting portion to the tip end of the tool body; The tool body includes:

[0019] In the tool body as described above, a plurality of second coolant supply passages may be provided.

[0020] In the tool body as described above, a pair of second coolant supply passages may be provided symmetrically about the central axis.

[0021] In the tool body as described above, the second coolant supply passage may be configured as a flow passage that becomes more distant from the central axis as it moves from the base end portion to the tip end portion.

[0022] In the tool body as described above, a spiral groove may be provided on the outer circumferential surface.

[0023] In the tool body as described above, the coolant discharge port may be disposed forward of the spiral groove in the rotation direction of the tool body.

[0024] Another aspect of the present invention is a cutting tool comprising the above-described core member and a tool body, wherein the second coolant supply passage is formed to communicate with the coolant groove of the core member when the core member is incorporated into the core mounting portion of the tool body in a predetermined orientation. [Brief explanation of the drawings]

[0025] [Figure 1] 1 is a perspective view showing a cutting tool according to an embodiment of the present invention. [Figure 2] FIG. 1 is a perspective view showing an example of a drill head (tool body) of a cutting tool. [Figure 3] FIG. 1 is a perspective view showing an example of a core member that can be attached to and detached from a drill head. [Figure 4A] FIG. 2 is an exploded perspective view showing a drill head, a core member, a cutting insert, etc. [Figure 4B] FIG. [Figure 5] FIG. 1 is a view of a drill head and the like as seen from the tip end side. [Figure 6A] 6 is a cross-sectional view of the drill head and the like taken along line VI-VI in FIG. 5. [Figure 6B] FIG. 6B is an enlarged view of a portion of FIG. 6A. [Figure 7] FIG. 2 is a perspective view showing an example of a core member. [Figure 8] FIG. 10 is a view of the core member as seen from the tip end side. [Figure 9] FIG. [Figure 10] 6 is a cross-sectional view of the drill head and the core member taken along line XX in FIG. 5. [Figure 11] FIG. 10 is a cross-sectional view of the drill head and the core member taken along line XI-XI in FIG. 5. [Figure 12] FIG. 11 is a perspective view of the drill head and core member with the cross section shown in FIG. 10. [Figure 13A] FIG. 10 is a perspective view of the core member with a central cutting edge (cutting insert) attached to the insert seat, as viewed from the tip end side. [Figure 13B] FIG. 2 is a perspective view of the core member as viewed from the base end side. DETAILED DESCRIPTION OF THE INVENTION

[0026] Hereinafter, preferred embodiments of a cutting tool, a tool body thereof, and a core member thereof according to the present invention will be described in detail with reference to the drawings (see FIG. 1, etc.).

[0027] A drilling tool 1 will be described below as an example of a preferred embodiment of the present invention (see FIG. 1, etc.). The drilling tool 1 of this embodiment is configured as a tool including a tool body 10, a core member 20 detachable from the tool body 10, a fixing means 30, etc. (see FIG. 4A, etc.).

[0028] Tool Body The tool body 10 is formed as a member to which the cutting insert 50 and the drill can be detachably attached, and functions as a so-called drill head when the cutting tool is the drilling tool 1 as in this embodiment. The tool body 10 of this embodiment has a shape that extends along a central axis 10x from a base end 10b to a tip end 10t, and is provided with a core attachment portion 11, a through hole 12, an outer peripheral surface 13, a chip discharge groove 14, an insert seat 15, an extension attachment / detachment portion 16, a guide pad attachment portion 17, a coolant supply passage 18, and the like (see FIG. 4A, etc.).

[0029] The core mounting portion 11 is provided at the tip end 10t of the tool body 10 so that the core member 20 is fitted along the central axis 10t. The core mounting portion 11 is formed as a circular hole having an inner peripheral surface 11p formed along the central axis 10x to match the outer shape of the core member 20, for example, a cylindrical shape, and a bottom surface 11b against which the base end 20b of the core member 20 abuts (see FIG. 6A, etc.). The core member 20 fitted into the core mounting portion 11 is fixed to the tool body 10 by fixing means 30 (see FIG. 6A, etc.).

[0030] The through hole 12 is provided as a hole for installation, such as by passing the fixing means 30 through it, and can take various forms depending on the specific example of the fixing means 30. For example, in this embodiment, a fixing screw is used as the fixing means 30, and the inner periphery of the through hole 12 is provided with an internal thread that screws into the fixing screw (see FIG. 4A, etc.). In this embodiment, the through hole 12 has a center line 12c that is oblique to the central axis 10x and is inclined toward the tip end 10t as it extends radially outward from the tool body 10, and penetrates from the outer circumferential surface 13 of the tool body 10 to the inner circumferential surface 11p of the core mounting portion 11 (see FIG. 6A, etc.). When the fixing means 30 is passed through the obliquely provided through hole 12 and pressed against the abutment surface 21 provided on the outer periphery of the core member 20, a component force along the central axis 10x acts in addition to a radial force. Therefore, the fixing means 30 not only applies a force pressing the core member 20 against the inner peripheral surface 11p, but also applies a force pressing the core member 20 against the bottom surface 11b of the core mounting portion 11 along the central axis 10x, so that the fixing means 30 presses the core member 20 toward the base end portion 10b along the axial direction and presses it against the bottom surface 11b, thereby more firmly fixing or holding the core member 20 (see FIG. 6B ). As long as the tool body 10 has such a structure, the angle α formed between the central axis 10x of the tool body 10 and the center line 12c of the through hole 12 is not particularly limited. However, in order to achieve the above-mentioned function, it is preferable that the angle α be 45° or more and less than 90°, and more preferably 74° or more and 76° or less, on the imaginary plane formed by the central axis 10x and the center line 12c. In addition, the angle α formed by the center axis 10x of the tool body 10 and the center line 12c of the through hole 12 may be the same as the angle formed by the center axis 10x and the perpendicular line 21v of the abutment surface 21 on the imaginary plane formed by the center axis 10x and the center line 12c.

[0031] The outer peripheral surface 13 of the tool body 10 has a large diameter portion 13t near the tip end 10t, a small diameter portion 13b closer to the base end 10b, and a tapered portion 13m connecting the large diameter portion 13t and the small diameter portion 13b (see FIG. 2, etc.). An opening of the through hole 12 is provided on the outer peripheral surface of the large diameter portion 13t (see FIG. 6).

[0032] The chip discharge grooves 14 are grooves for discharging chips generated during cutting together with coolant. In the tool body 10 of this embodiment, a pair of two spiral chip discharge grooves 14 are provided on the outer circumferential surface 13 so as to be axially symmetrical with respect to the central axis 10x (see FIG. 5, etc.).

[0033] The insert seat 15 is a seat for mounting the cutting insert 50 to the tool body 10. The specific aspects of such an insert seat 15 and the cutting insert 50 mounted therein are not particularly limited, and a plurality of insert seats 15 may be provided radially outward of the core mounting portion 11. As an example, in this embodiment, a total of four insert seats 15 are arranged linearly in the radial direction, with two on either side of the central axis 10x (see FIG. 5, etc.). Each of these insert seats 15 is configured to mount a cutting insert 50 in a predetermined orientation (see FIG. 2, etc.).

[0034] The extension detachable portion 16 is a portion for attaching the extension 62 (see FIGS. 1 and 2, etc.). Although not specifically shown, the adapter 60 may be attached directly to the extension detachable portion 16 without the extension 62.

[0035] The guide pad mounting portion 17 is a portion provided for mounting a guide pad 70. The guide pad 70 is a member that functions as a guide by contacting the inner wall surface of a hole in a workpiece that has been cut by the cutting insert 50 or the like. The guide pad 70 is mounted on the guide pad mounting portion 17 and is attached and fixed to the side portion (outer peripheral surface 13) of the tool body 10 by a set screw 72 (see FIG. 2, etc.).

[0036] The coolant supply passage 18 is a flow path provided to supply coolant to the cutting edge at the tip of the drilling tool 1 (for example, the cutting edge of the cutting insert 40 that constitutes the central cutting edge). In the tool body 10 of this embodiment, a circular first coolant supply passage 18A extending straight along the central axis 10x from the base end 10b to the tip end 10t is provided inside the tool body 10 (see FIGS. 6 and 11). The tip end side of the first coolant supply passage 18A opens at the bottom surface 10b of the core mounting portion 11, and supplies coolant toward the coolant groove 28 of the core member 20.

[0037] The tool body 10 is further provided with a second coolant supply passage 18B and a coolant discharge port 19 (see FIG. 10 ). The second coolant supply passage 18B is provided to communicate from the inner circumferential surface 11p of the core mounting portion 11 of the tool body 10 to the tip end 10t of the tool body 10, and the specific form thereof is not particularly limited. As an example, in the tool body 10 of this embodiment, two second coolant supply passages 18B are provided symmetrically about the central axis 10x so as to form a pair (see FIGS. 10 and 12 ). Furthermore, these two second coolant supply passages 18B are configured to diverge from the central axis 10x as they extend from the base end 10b of the tool body 10 toward the tip end 10t of the tool body 10 (see FIGS. 10 and 12 ). In this case, the centrifugal force acting during rotation of the tool body 10 can also act as a force to send coolant toward the tip end 10t.

[0038] The coolant discharge ports 19 are outlets through which coolant that has flowed through the coolant supply paths 18 (first coolant supply path 18A, second coolant supply path 18B) is discharged. In the tool body 10 of this embodiment, the coolant discharge ports 19 are disposed in each of the two second coolant supply paths 18B at positions forward of the chip discharge grooves (spiral grooves) 14 in the rotation direction of the tool body 10 (see FIGS. 4A and 5). The coolant discharged from the coolant discharge ports 19 disposed in this manner easily sends chips into the chip discharge grooves (spiral grooves) 14 and allows them to be discharged.

[0039] [Core material] The core member 20 is a steel member (steel body) that can be attached to and detached from the core attachment portion 11 of the tool body 10 described above (see FIGS. 3 to 9). The core member 20 may be a so-called solid drill having an integrated cutting edge at its tip, or a replaceable cutting edge or replaceable head member. As an example, in this embodiment, a core member 20 having a replaceable head structure will be described. The core member 20 of this embodiment has a substantially cylindrical shape (including a cylindrical shape) extending along the central axis 20x, and includes an abutment surface 21, a spiral groove 22, an insert seat 23, a coolant groove 28, a coolant flow path 29, etc.

[0040] The abutment surface 21 is formed as a surface with which a portion of the fixing means 30 abuts. In this embodiment, a portion of the outer peripheral surface 20p of the core member 20 is cut out, and the abutment surface 21 is formed in the cutout portion (see FIG. 7, etc.). The core member 20 is assembled into the core attachment portion 11 along the central axis 10x of the tool body 10, and in this state, a portion of the fixing means 30 is brought into abutment with the abutment surface 21, thereby fixing the core member 20 to the tool body 10 (see FIG. 3, etc.). The abutment surface 21 is inclined with respect to an imaginary plane (indicated by the symbol VP in FIG. 6) perpendicular to the central axis 20x of the core member 20, and is provided so as to face outward and toward the tip end 20t of the core member 20 (see FIG. 9, etc.). It is preferable that the angle β formed by the central axis 20x of core member 20 and the perpendicular line 21v of abutment surface 21 is 45° or more and less than 90° on an imaginary plane (see the plane that appears as a cross section in FIG. 6B) formed by central axis 20x and perpendicular line 21v (see FIG. 9). An example of a preferable range for angle β is 74° or more and 76° or less.

[0041] In this embodiment, such abutment surface 21 is provided near the base end 20b of the core member 20 (see FIG. 7, etc.), but this is merely an example, and conversely, it may be provided near the tip end 20t, or near the center in the longitudinal direction along the central axis 20x. Also, in this embodiment, the abutment surface 21 is configured as a flat surface (see FIG. 9, etc.), but for example, this abutment surface 21 may be configured as a surface that includes at least a partial curved surface. Although not particularly shown, for example, by configuring the abutment surface 21 as a concave surface and configuring a portion of the fixing means 30 (the portion abutting the abutment surface 21) as a convex surface that matches this concave surface, it becomes possible to perform autonomous alignment or centering when the fixing means 30 is pressed against the abutment surface 21. Although not specifically shown, the opposite structure may be used, that is, the abutment surface 21 may be configured as a convex surface and a portion of the fixing means 30 (the portion that abuts against the abutment surface 21) may be configured as a concave surface that matches this convex surface, or the abutment surface 21 may be configured as a convex surface and a portion of the fixing means 30 (the portion that abuts against the abutment surface 21) may be configured as a flat surface. In the latter case, the position where the fixing means 30 and the abutment surface 21 abut is less susceptible to the influence of manufacturing tolerances, and the core member 20 can be fixed precisely in the designed position.

[0042] The spiral groove 22 is formed by a groove spirally provided on the outer periphery of the core member 20. In the core member 20 of this embodiment, two pairs of spiral grooves 22 are provided on the outer periphery surface 20p so as to be axially symmetrical with respect to the central axis 20x (see FIG. 8, etc.). Furthermore, the spiral groove 22 is formed so as to smoothly connect with the chip discharge groove 14 of the tool body 10 when the core member 20 is assembled into the core mounting part 11, or to form a surface that smoothly connects with it (see FIG. 2, etc.). Because the chip discharge groove 14 is formed in this way and has a shape without steps, there are no obstacles when chips are discharged, which improves chip discharge performance.

[0043] The insert seat 23 is provided at the front end portion 20t of the core member 20 so that the cutting insert (chip) 40 can be attached along the central axis 20x (see FIG. 4A, etc.). A threaded hole 23h is provided near the insert seat 23, through which a fixing screw 23s for fixing the cutting insert 40 passes. In this manner, the cutting insert 40 attached to the insert seat 23 along the central axis 20x functions as the central cutting edge of the drilling tool 1. The front end of the cutting insert 40, which functions as the central cutting edge of the drilling tool 1, has a rake face 41 facing forward in the tool rotation direction and a flank face 42 facing in the axial direction of the central axis 10x and gradually moving away from the front end as it approaches the rear end in the tool rotation direction, and the intersection of the rake face 41 and the flank face 42 forms a cutting edge 43 (see FIGS. 4A and 4B). Furthermore, although an example has been shown here in which a single insert seat 23 is provided at the center of the drilling tool 1, other embodiments are possible, such as an indexable drill, which is not specifically shown, in which multiple insert seats 23 are arranged around the central axis 20x and indexable inserts are attached to these insert seats 23.

[0044] The coolant groove 28 is provided in the base end 20b of the core member 20. When the core member 20 is assembled into the core mounting portion 11 of the tool body 10, the coolant groove 28 communicates with the coolant supply passage 18 of the tool body 10 to form a flow passage through which the coolant flows (see FIG. 6A, etc.). The shape and structure of the coolant groove 28 are not particularly limited, and may be formed as a single groove or multiple grooves. In the core member 20 of this embodiment, the coolant groove 28 is formed as two grooves, a first coolant groove 281 and a second coolant groove 282, which intersect in a crisscross pattern (see FIGS. 7, 13B, etc.). An inlet 29a of the coolant flow passage 29 is provided in the bottom surface 281b of the first coolant groove 281. In the core member 20 of this embodiment, the two inlets 29a are provided symmetrically about the central axis 20x (see FIGS. 11 and 13B).

[0045] The coolant flow passages 29 are, for example, a plurality of flow passages provided inside the core member 20, and guide the coolant that has flowed into the coolant grooves 28 to the tip end 20t and discharges it. The coolant flow passages 29 in the core member 20 of this embodiment are configured with two flow passages that run from a part of the coolant grooves 28 (for example, the bottom surface 281b of the first coolant groove 281) to the coolant discharge ports 29e (see, for example, Figures 7, 8, 12, etc.). The pair of coolant discharge ports 29e are positioned to discharge the coolant toward the cutting edge at the tip of the drilling tool 1 (for example, the cutting edge of the cutting insert 40 that forms the central cutting edge) (see, for example, Figure 13A). The two coolant flow passages 29 in the core member 20 of this embodiment are arranged symmetrically about the central axis 20x (see, for example, Figure 11, etc.). Moreover, these coolant flow paths 29 are configured so as to gradually move away from the central axis 20x from the base end portion 20b toward the tip end portion 20t, so as to fan out (see FIG. 11).

[0046] The core member 20 of this embodiment, which has such a structure, is capable of supplying coolant from the base end 20b to the tip end 20t through the above-described coolant flow path 29. Therefore, it is possible to provide the coolant discharge port 29e at a desired position without forming a complicated flow path as in the conventional case.

[0047] [Fixing means] The fixing means 30 is used to fix the core member 20 assembled in the core mounting portion 11 of the tool body 10. As described above, in this embodiment, a fixing screw is used as the fixing means 30 (see FIG. 6A, etc.), but this is one example of a suitable means for fixing the core member 20, and it goes without saying that a member other than a screw may also be used. As a member other than a screw, for example, a biasing member that utilizes elastic deformation (a spring member, a deformed portion of the tool body 10, etc.) may also be used. Furthermore, the form of the through-hole 12 can be appropriately changed (for example, changed to a structure in which a biasing member is housed in a non-through hole) in accordance with the form of the fixing means 30.

[0048] [Drilling tools] The drilling tool 1 of this embodiment is configured as a tool including the above-described tool body 10, a core member 20 detachably attached to the tool body 10, and a fixing means 30 (see FIG. 4A, etc.). When the core member 20 is assembled in a predetermined orientation into the core mounting portion 11 of the tool body 10 and fixed by the fixing means 30 (see FIG. 6A, etc.), the second coolant supply passage 18B communicates with the second coolant groove 282 in the coolant groove 28 of the core member 20 (see FIG. 10). A portion of the coolant supplied from the first coolant supply passage 18A flows into the second coolant supply passage 18B through the coolant groove 28 of the core member 20 and is discharged from the coolant discharge port 19.

[0049] According to the above-described tool body 10, core member 20, and fixing means 30, or the drilling tool 1 configured by these, the fixing means 30 presses the outer peripheral surface 20p of the core member 20 in a direction inclined with respect to an imaginary plane VP perpendicular to the central axis 20x of the core member 20, thereby generating a component force in a direction along the central axis 10x of the tool body 10 or the central axis 20x of the core member 20, and it is possible to fix the core member 20 more firmly. In this regard, conventional large-diameter drilling tools with cartridge-type insert seats for central cutting inserts have the advantage over non-cartridge-type tools that the insert seat for the central cutting edge can be replaced if the insert seat for the central cutting edge is damaged. However, the cylindrical part that serves as the central cutting edge is sometimes inserted into an insertion hole located at the center of the axial tip of the drilling tool body and fixed by pressing a flat surface parallel to the central axis of the part against the side of the part with the tip of a screw inserted into a threaded hole that runs perpendicular to the central axis of the tool body from the outer surface of the tool body to the inner surface of the insertion hole. With this fixing method, it must be said that forces parallel to the central axis of the part can only be withstood by the friction force generated between the inner surface of the insertion hole and the outer surface of the part due to the pressing force of the screw. In contrast, the advantages of the drilling tool 1 of this embodiment are as described above.

[0050] Furthermore, according to the drilling tool 1 of this embodiment, a replaceable central blade (cutting insert 40) is incorporated into the core member 20, and the core member 20 is incorporated into the tool body 10, creating a so-called double structure, which makes it easier to prevent damage or deformation of the tool body 10 itself, and also makes it possible to firmly fix the core member 20 to the tool body 10, making it easier to demonstrate stable cutting performance even when processing under high-efficiency conditions or in unstable conditions.

[0051] While the above-described embodiment is one example of a preferred embodiment of the present invention, it is not limited to this and various modifications are possible without departing from the spirit of the present invention. For example, the drilling tool 1 described in the above embodiment is a so-called indexable tool with a dual structure in which the core member 20 is detachably attached to the tool body (drill head) 10 and the central cutting edge (cutting insert 40) is detachably attached to the core member 20. However, this is merely one preferred example, and it goes without saying that the present invention can also be applied to other structures, such as tools with brazed tips of cemented carbide or the like (for example, a tipped drill with brazed tips of cemented carbide or other materials as cutting edges, or the core member 20).

[0052] In the above embodiment, the present invention is applied to the drilling tool 1, but this is merely one example of a cutting tool to which the present invention can be applied. In addition to drilling tools (drills), the present invention can also be applied to milling tools such as end mills.

[0053] Although the above description has been given using the cutting tool (drilling tool) having a so-called double structure as an example, the present invention can also be applied to a cutting tool having a so-called triple structure. For example, the present invention can also be applied to a cutting tool having a so-called triple structure in which the core member 20 is a so-called solid drill in which a drill serving as a central cutting edge is integrally provided at the tip portion 20t, and cutting inserts are disposed on the outer periphery (outside the central cutting edge) of the solid drill, and this is further combined with the tool body 10. [Industrial Applicability]

[0054] The present invention is suitably applied to a tool body of a cutting tool and its core member. [Explanation of symbols]

[0055] 1...Drilling tools (cutting tools) 10...Tool body 10b...Proximal end 10t...Tip 10x…center axis 11...Core mounting part 11b…Bottom surface 11p…Inner peripheral surface 12...Through hole 12c...Center line (of the hole) 13...Outer surface 13b…Small diameter part 13t...large diameter section 13m...Tapered section 14...Chip discharge groove (spiral groove) 15...insert seat 16...Extension attachment / detachment part 17...Guide pad attachment part 18...Coolant supply passage 18A...First coolant supply line 18B...Second coolant supply passage 19...Coolant outlet 20...Core member 20b...Proximal end 20p…outer surface 20t...Tip 20x…center axis 21...Abutment surface 21v...perpendicular to the contact surface 22...Spiral groove 23...insert seat 23h...screw hole 23s...Fixing screw 28...Coolant groove (at base end) 281...1st coolant groove 281b...Bottom surface (of first coolant groove) 282...Second coolant groove 29...Coolant passage 29a...Inlet of coolant passage 29e...Coolant outlet 30...Fixing means 40...Central cutting edge (cutting insert) 41...Scooping surface 42...flank 43...Cutting edge 50...Cutting insert 60...Adapter 62...Extension 70...Guide pad 72...Set screw α: Angle between the central axis 10x of the tool body 10 and the center line 12c of the through hole 12 β: Angle between the central axis 20x of the core member 20 and the perpendicular line 21v of the contact surface 21 VP...imaginary plane (perpendicular to the central axis)

Claims

1. A core member detachable from a tool body of a cutting tool, a coolant groove provided at a base end of the core member along a central axis of the core member; a coolant flow path communicating from the coolant groove to a tip end portion of the core member; and A core member having a plurality of the coolant grooves.

2. 2. The core member according to claim 1, wherein an inlet of the coolant flow passage is provided on a bottom surface of the coolant groove.

3. The core member according to claim 1 , wherein a plurality of the coolant passages are provided.

4. 4. The core member according to claim 3, wherein two of said coolant flow passages forming a pair are provided symmetrically about said central axis.

5. 4. The core member according to claim 3, wherein the coolant flow passage is configured as a flow passage that moves away from the central axis as it moves from the base end portion to the tip end portion.

6. The core member according to claim 1 , wherein a spiral groove is provided on the outer peripheral surface.

7. A core member detachable from a tool body of a cutting tool, a coolant groove provided at a base end of the core member along a central axis of the core member; a coolant flow path communicating from the coolant groove to a tip end portion of the core member; and A cylindrical core member.

8. A core member detachable from a tool body of a cutting tool, a coolant groove provided at a base end of the core member along a central axis of the core member; a coolant flow path communicating from the coolant groove to a tip end portion of the core member; and A core member having an insert seat at its tip, on which a cutting insert is attached.

9. The core member according to claim 8 , wherein the insert seat is disposed so as to surround the central axis.

10. The core member according to any one of claims 1 to 5, which is a drill.

11. A tool body of a cutting tool to which a cutting insert and a drill can be detachably attached, a core mounting portion into which a core member having a cutting edge is mounted along a central axis of the tool body; a first coolant supply passage for supplying coolant from a base end side toward the core attachment portion; a second coolant supply passage communicating from an inner peripheral surface of the core mounting portion to a coolant discharge port at a tip end of the tool body; A tool body comprising:

12. The tool body according to claim 11 , wherein a plurality of the second coolant supply passages are provided.

13. The tool body according to claim 12 , wherein the pair of second coolant supply passages are provided symmetrically about the central axis.

14. The tool body according to claim 12 , wherein the second coolant supply passage is configured as a flow passage that moves away from the central axis as it moves from the base end portion to the tip end portion.

15. 15. A tool body according to any one of claims 11 to 14, wherein the outer peripheral surface is provided with a spiral groove.

16. The tool body according to claim 15 , wherein the coolant discharge port is disposed forward of the spiral groove in the rotation direction of the tool body.

17. A cutting tool comprising the core member according to any one of claims 1 to 5 and the tool body according to any one of claims 11 to 14, the second coolant supply passage is formed to communicate with the coolant groove of the core member when the core member is incorporated into the core mounting portion of the tool body in a predetermined orientation.

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