Cutting insert and blade edge replaceable cutting tool

Abstract

To provide a cutting insert which enables reduction of replacement frequency and reduction of running costs, and to provide a blade edge replaceable cutting tool including the cutting insert.SOLUTION: A cutting insert includes: a rod-like first body extending along a first direction; and a rod-like second body connected to the first body through a bending part and extending along a second direction different from the first direction. A first major surface is provided with a first cutting blade and a first recessed groove extending along the first direction. The second major surface is provided with a second cutting blade and a second recessed groove extending along the second direction. An extending length of the first body from the bending part is the same as an extending length of the second body from the bending part.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a cutting insert and an indexable cutting tool. [Background technology]

[0002] 2. Description of the Related Art Conventionally, a cutting tool for internal grooving having an L-shaped cutting insert has been known (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent No. 6346200 Summary of the Invention [Problem to be solved by the invention]

[0004] The L-shaped cutting insert described in Patent Document 1 is configured to have only one cutting edge portion, and therefore has a problem in that the cutting insert itself needs to be replaced frequently, resulting in high running costs. [Means for solving the problem]

[0005] (1) According to one aspect of the present invention, there is provided a cutting insert that is attached to an insert mounting seat of a holder for an indexable cutting tool for use. The cutting insert includes a rod-shaped first body portion extending in a first direction, and a rod-shaped second body portion connected to the first body portion via a bent portion and extending in a second direction different from the first direction. When a surface on one side of the cutting insert as viewed from a third direction perpendicular to both the first direction and the second direction is defined as a first main surface and a surface opposite to the first main surface is defined as a second main surface, the first main surface is provided with a first cutting edge located at a tip portion of the first body portion opposite to the bent portion, and a first groove extending from a position closer to the bent portion than the first cutting edge along an extension direction of the first body portion and reaching a region on the bent portion. The second main surface is provided with a second cutting edge located at a tip end portion of the second body portion opposite to the bent portion, and a second groove extending from a position closer to the bent portion than the second cutting edge along the extension direction of the second body portion to reach a region on the bent portion. The extension length of the first body portion from the bent portion and the extension length of the second body portion from the bent portion are the same.

[0006] According to this configuration, a cutting insert having an L-shaped bent shape and a two-corner type cutting insert with a symmetrical shape on the front and back sides, in which the first and second main surfaces have the same shape when turned over, is provided. Since two corners of one cutting insert can be used, the frequency of replacement can be reduced compared to conventional L-shaped cutting inserts, and running costs can be suppressed.

[0007] (2) The first main surface may have a first pressing groove extending along the extension direction of the second main body portion in a region above the second main body portion, and the second main surface may have a second pressing groove extending along the extension direction of the first main body portion in a region above the first main body portion.

[0008] (3) The area of ​​the first main surface on the second main body portion may be configured as a first pressed surface consisting of a flat surface, and the area of ​​the second main surface on the first main body portion may be configured as a second pressed surface consisting of a flat surface.

[0009] (4) According to one aspect of the present invention, there is provided an indexable cutting tool including a holder having an insert mounting seat with a pressing surface and a seating surface facing each other, and the cutting insert of (1) above, which is held by the insert mounting seat and has a pressed surface and a seating surface that contact the pressing surface and the seating surface, respectively. The holder includes an upper jaw and a lower jaw for gripping the cutting insert. The lower jaw has the seating surface on a surface facing the upper jaw, and the seating surface is provided with a support protrusion that fits into the first groove or the second groove of the cutting insert. The upper jaw has, on a surface facing the lower jaw, the pressing surface and a protrusion that protrudes toward the lower jaw and is disposed in the second groove or the first groove at the bent portion.

[0010] (5) According to one aspect of the present invention, there is provided a cutting tool including a holder having an insert mounting seat with a pressing surface and a seating surface facing each other, and the cutting insert of (2) above, which is held by the insert mounting seat and has a pressed surface and a seating surface that contact the pressing surface and the seating surface, respectively. The holder includes an upper jaw and a lower jaw for gripping the cutting insert. The lower jaw has the seating surface on a surface facing the upper jaw, and the seating surface is provided with a support protrusion that fits into the first groove or the second groove of the cutting insert. The upper jaw has, on a surface facing the lower jaw, the pressing surface and a protrusion that protrudes toward the lower jaw and is disposed in the second groove or the first groove located at the bent portion of the cutting insert. The pressing surface of the upper jaw is provided with a pressing protrusion that fits into the second pressing groove or the first pressing groove of the cutting insert.

[0011] (6) According to one aspect of the present invention, there is provided a cutting tool including a holder having an insert mounting seat with a pressing surface and a seating surface facing each other, and the cutting insert of (3) above, which is held by the insert mounting seat and has a pressed surface and a seating surface that contact the pressing surface and the seating surface, respectively. The holder includes an upper jaw portion and a lower jaw portion for gripping the cutting insert. The lower jaw portion has the seating surface on a surface facing the upper jaw portion, and the seating surface is provided with a support protrusion portion that fits into the first groove or the second groove of the cutting insert. The upper jaw portion has, on a surface facing the lower jaw portion, the pressing surface and a protrusion portion that protrudes toward the lower jaw portion and is disposed in the second groove or the first groove located at the bent portion of the cutting insert. The pressing surface of the upper jaw portion is a flat surface that presses the second pressed surface or the first pressed surface of the cutting insert. Effect of the Invention

[0012] According to one aspect of the present invention, there is provided a cutting insert that can reduce replacement frequency and running costs, and an indexable cutting tool including the cutting insert. [Brief description of the drawings]

[0013] [Figure 1] FIG. 1 is a partial perspective view of an indexable cutting tool according to an embodiment. [Figure 2A] FIG. 2A is a plan view of the cutting insert of the embodiment as viewed from a first main surface side. [Figure 2B] FIG. 2B is a side view of the cutting insert of the embodiment. [Figure 2C] FIG. 2C is a plan view of the cutting insert of the embodiment as viewed from the second main surface side. [Diagram 3] FIG. 3 is a partial side view of the indexable cutting tool according to the embodiment. [Figure 4] FIG. 4 is a partial side view of the holder of the embodiment. [Diagram 5] FIG. 5 is a partial cross-sectional view taken along line VV in FIG. [Figure 6A]FIG. 6A is a plan view of a cutting insert of a modified example as viewed from a first main surface side. [Figure 6B] FIG. 6B is a plan view of the cutting insert of the modified example as viewed from the second main surface side. [Figure 7] FIG. 7 is a partial side view of a modified holder. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0014] FIG. 1 is a partial perspective view of an indexable cutting tool of an embodiment. FIG. 2A is a plan view of a cutting insert of an embodiment, and FIG. 2B is a side view of the cutting insert. FIG. 2C is a plan view of the cutting insert from the opposite side to FIG. 2A. FIG. 3 is a partial side view of an indexable cutting tool of an embodiment. FIG. 4 is a partial side view of a holder of an embodiment. FIG. 5 is a partial cross-sectional view along line VV of FIG. 3.

[0015] The indexable cutting tool 100 shown in FIG. The holder 1 has a rectangular prism-shaped shank portion 2 and a head portion 3 connected to the longitudinal tip of the shank portion 2. The holder 1 is made of, for example, steel. In this embodiment, the direction from the shank portion 2 to the head portion 3 in the indexable cutting tool 100 is called the tip side, and the direction from the head portion 3 to the shank portion 2 is called the rear end side.

[0016] As shown in Figs. 1 and 4, the head portion 3 has a slit 3a extending from the tip of the head portion 3 toward the shank portion 2. The portion of the head portion 3 above the slit 3a is the upper jaw portion 3b, and the portion below the slit 3a is the lower jaw portion 3c. As shown in Fig. 4, the shank portion 2 is connected to the rear of the lower jaw portion 3c of the head portion 3. The height position of the slit 3a roughly coincides with the height position of the upper surface 2b of the shank portion 2. The connection portion 3d between the upper jaw portion 3b and the lower jaw portion 3c is thin, and the upper jaw portion 3b can be deformed so as to bend toward the lower jaw portion 3c with the connection portion 3d as a fulcrum.

[0017] The lower jaw 3c has a generally rectangular plate-shaped pedestal 4 at its tip. A pedestal surface 5 having a rectangular shape in a plan view is formed on the upper surface of the pedestal 4. The pedestal surface 5 extends from the tip of the lower jaw 3c in the longitudinal direction of the holder 1 to the middle of the slit 3a.

[0018] The base surface 5 has a support protrusion 5a that protrudes toward the upper jaw portion 3b. As shown in Figures 4 and 5, the support protrusion 5a is a linear protrusion that extends along the extension direction of the base surface 5 (the left-right direction in Figure 4). As shown in Figure 5, the support protrusion 5a is a protrusion with a convex V-shaped cross section, with the central portion in the width direction of the base surface 5 swelling upward in the figure.

[0019] The upper jaw 3b has a pressing portion 6 at its tip. The pressing portion 6 is a triangular plate in a side view, tapered toward the tip. The tip of the pressing portion 6 is located rearward of the tip of the lower jaw 3c. A pressing surface 7 is formed on the surface of the pressing portion 6 facing the base 4. The pressing surface 7 extends from the tip of the upper jaw 3b to the middle of the slit 3a. The rear end of the pressing surface 7 is located forward of the rear end of the base surface 5.

[0020] The pressing surface 7 has a pressing protrusion 7a that protrudes toward the lower jaw 3c. As shown in Figures 4 and 5, the pressing protrusion 7a is a linear protrusion that extends along the extension direction of the pressing surface 7 (the left-right direction in Figure 4). As shown in Figure 5, the pressing protrusion 7a is a protrusion with a convex V-shaped cross section, with the central part in the width direction of the pressing surface 7 swelling downward in the figure.

[0021] The upper jaw 3b has a protrusion 6a that protrudes downward (toward the lower jaw 3c) on the underside of the tip of the pressing portion 6. The lower end of the protrusion 6a is at approximately the same height as the lower end of the pressing protrusion 7a. Therefore, the protrusion 6a protrudes toward the lower jaw 3c further than the base of the pressing protrusion 7a. The protrusion 6a is a linear protrusion that extends in a direction perpendicular to the direction in which the pressing surface 7 extends.

[0022] In the holder 1, the seat surface 5 of the seat portion 4 and the pressing surface 7 of the pressing portion 6 are disposed opposite to each other in the vertical direction.

[0023] The holder 1 is provided with a clamp screw 9 that is inserted from above into the head portion 3 at the tip of the holder 1 as a clamping means for the insert mounting seat 8. The clamp screw 9 passes through the slit 3a from the upper jaw portion 3b side and is tightened into a screw hole in the lower jaw portion 3c. By tightening the clamp screw 9, the cutting insert 10 that is inserted between the upper jaw portion 3b and the lower jaw portion 3c can be fixed.

[0024] The cutting insert 10 is fixed by being sandwiched vertically between the base portion 4 and the pressing portion 6 of the insert mounting seat 8. The cutting insert 10 is made of, for example, a cemented carbide alloy. As shown in Figs. 2A and 2B, the cutting insert 10 is a cutting insert having an L-shaped bend in a plan view. The cutting insert 10 includes a rod-shaped first body portion 11 extending along a first direction d1, and a rod-shaped second body portion 12 connected to the first body portion 11 via a bent portion 13 and extending along a second direction d2 different from the first direction d1. In this embodiment, the first body portion 11, the second body portion 12, and the bent portion 13 are part of the cutting insert 10 of a single member. In this embodiment, the positive side of the first body portion 11 in the first direction d1 is the tip side of the first body portion 11, and the positive side of the second body portion 12 in the second direction d2 is the tip side of the second body portion 12.

[0025] 2, in the cutting insert 10, one surface of the cutting insert 10 viewed from a third direction d3 perpendicular to both the first direction d1 (extension direction of the first body portion 11) and the second direction d2 (extension direction of the second body portion 12) is defined as a first main surface 21, and the surface opposite to the first main surface is defined as a second main surface 22. In this embodiment, the surface of the cutting insert 10 facing the positive side of the third direction d3 is defined as the first main surface 21, and the surface of the cutting insert 10 facing the negative side of the third direction d3 is defined as the second main surface 22.

[0026] As shown in FIG. 2A, the first main surface 21 is provided with a first cutting edge 31 located at the tip portion opposite the bent portion 13 of the first main body portion 11, and a first groove 41 extending along the first direction d1 from a position closer to the bent portion 13 than the first cutting edge 31 and reaching the area above the bent portion 13.

[0027] The first cutting edge 31 is formed on three sides of the tip of the first main body 11 on the first main surface 21. The first cutting edge 31 is formed on a side extending in a direction (second direction d2) intersecting the extension direction of the first main body 11 and two sides adjacent to this side extending in the extension direction of the first main body 11 (first direction d1) at the tip of the first main body 11. A side surface of the first main body 11 connected to the first cutting edge 31 is defined as a clearance surface 31a of the first cutting edge 31. A part of the first main surface 21 of the first main body 11 connected to the first cutting edge 31 is defined as a scooping surface 31b. In this embodiment, the scooping surface 31b is a trapezoidal shape that widens toward the tip of the first main body 11 in a plan view.

[0028] A first groove 41 is formed from an end of the rake face 31b on the bent portion 13 side along the direction in which the first main body portion 11 extends (first direction d1). The first groove 41 reaches from above the first main body portion 11 to an area above the bent portion 13, and further, an end of the first groove 41 opposite the rake face 31b reaches the side surface of the bent portion 13 opposite to the first main body portion 11. The first groove 41 is formed on the upper surface of the portion where the cutting insert 10 is bent.

[0029] The first groove 41 is formed in a V-shape by a pair of inclined surfaces 41a, 41b which move away from each other toward the upper side in a vertical cross section perpendicular to the first direction d1. In this embodiment, the height position of the upper end of the first groove 41 is located on the positive side of the third direction d3 relative to the height position of the scooping face 31b. The height position of the scooping face 31b is approximately the same as the height position of the bottom of the first groove 41. Between the region where the first groove 41 is formed and the scooping face 31b, an inclined surface 11a is formed which descends from the upper end of the first groove 41 toward the scooping face 31b.

[0030] In this embodiment, the inclined surfaces 41a and 41b are convex curved surfaces that are slightly convex upward when viewed from a side in the first direction d1 as shown in Fig. 2B. The cross-sectional shape of the inclined surfaces 41a and 41b is not particularly limited, and may be a flat surface or a concave curved surface.

[0031] A first pressing groove 51 extending along the second direction d2 is provided in the first main surface 21 in an area on the second body portion 12. The first pressing groove 51 extends linearly from the tip of the second body portion 12 to a connection portion of the second body portion 12 with the bent portion 13. In the vicinity of the connection portion between the second body portion 12 and the bent portion 13, an end portion of the first pressing groove 51 opens in a V-shape on the inner wall of the first groove 41. The bottom of the first pressing groove 51 and the bottom of the first groove 41 are connected.

[0032] The first pressing groove 51 is formed in a V-shape by a pair of inclined surfaces 51a, 51b that move away from each other toward the upper side in a vertical cross section perpendicular to the second direction d2. In this embodiment, the height position of the upper end of the first pressing groove 51 coincides with the height position of the upper end of the first groove 41. The height position of the bottom of the first pressing groove 51 approximately coincides with the height position of the bottom of the first groove 41.

[0033] In this embodiment, the inclined surfaces 51a and 51b are convex curved surfaces that are slightly convex upward when viewed from the side in the second direction d2. The cross-sectional shape of the inclined surfaces 51a and 51b is not particularly limited, and may be a flat surface or a concave curved surface.

[0034] As shown in FIG. 2C, the second main surface 22 is provided with a second cutting edge 32 located at the tip portion opposite the bent portion 13 of the second main body portion 12, and a second groove 42 extending along the second direction d2 from a position closer to the bent portion 13 than the second cutting edge 32 and reaching the area above the bent portion 13. The second cutting edge 32 has the same shape as the first cutting edge 31 of the first body portion 11. A clearance surface 32a (see FIG. 2B) is provided on the side surface of the second body portion 12 connected to the second cutting edge 32. A rake surface 32b is provided on the upper surface of the second body portion 12 connected to the second cutting edge 32.

[0035] The second groove 42 is formed in the same shape and length as the first groove 41 of the first main body portion 11. The second groove 42 has an inclined surface 42a and an inclined surface 42b. The second groove 42 extends from the end of the rake face 32b on the bent portion 13 side to the side surface of the bent portion 13 facing the negative side in the second direction d2. Between the region where the second groove 42 is formed and the rake face 32b, an inclined surface 12a is formed that descends from the upper end of the second groove 42 toward the rake face 32b.

[0036] A second pressing groove 52 extending along the first direction d1 is provided in the second main surface 22 in an area on the first body portion 11. The second pressing groove 52 is formed to have the same shape and length as the first pressing groove 51 in the first main surface 21. The second pressing groove 52 has an inclined surface 52a and an inclined surface 52b.

[0037] In the cutting insert 10 of this embodiment, the extension length L1 of the first body portion 11 from the bent portion 13 and the extension length L2 of the second body portion 12 from the bent portion 13 are the same. Note that "extension lengths L1, L2 are the same" also includes a case where a slight difference occurs between the extension lengths L1, L2 due to manufacturing errors.

[0038] The cutting insert 10 of this embodiment having the above configuration is a two-corner type cutting insert capable of using the first cutting edge 31 and the second cutting edge 32. That is, the cutting insert 10 is a cutting insert having a symmetrical shape between the front and back, in which the first main surface 21 and the second main surface 22 have the same shape when turned over.

[0039] A case in which the first cutting edge 31 of the cutting insert 10 is used will be described. When the first cutting edge 31 is used, the cutting insert 10 is attached by inserting the second body portion 12 into the insert attachment seat 8 of the holder 1. In this case, the area of ​​the first main surface 21 on the second body portion 12, i.e., the surface of the second body portion 12 facing the positive side in the third direction d3, is the pressed surface facing the pressing surface 7 of the pressing portion 6. Also, the area of ​​the second main surface 22 on the second body portion 12, i.e., the surface of the second body portion 12 facing the negative side in the third direction d3, is the seating surface facing the seating surface 5 of the seat portion 4.

[0040] With the seating surface (second main surface 22) of the cutting insert 10 supported from below by the seating surface 5 of the insert mounting seat 8, the clamp screw 9 is tightened, whereby the pressing surface 7 of the pressing part 6 is pressed against the pressed surface (first main surface 21) of the cutting insert 10. As a result, the cutting insert 10 is fixed in a sandwiched state between the upper jaw part 3b and the lower jaw part 3c.

[0041] 5, the support protrusion 5a of the seat surface 5 fits into the second groove 42 of the cutting insert 10. Also, the pressing protrusion 7a of the pressing surface 7 fits into the first pressing groove 51 of the cutting insert 10. According to this clamping mechanism, even if a force is applied in the width direction of the cutting insert 10 (the horizontal direction perpendicular to the direction in which the second body portion 12 extends), the cutting insert 10 is firmly fixed by the fitting structure of the protrusion and the recessed groove, so that the cutting insert 10 can be prevented from shifting from the clamping position. This can prevent a decrease in machining accuracy due to the positional shift of the cutting insert 10, and also prevents the cutting insert 10 from being damaged or falling off.

[0042] Furthermore, when the clamp screw 9 is tightened to fix the cutting insert 10, the upper jaw 3b may be tilted with respect to the cutting insert 10. This is because the clamp screw 9 is located at a position offset from the extension line of the upper jaw 3b and the lower jaw 3c. Even in this case, in this embodiment, the pressing protrusion 7a of the upper jaw 3b is fitted into the first pressing groove 51 of the cutting insert 10, so that even if the upper jaw 3b is slightly tilted, the contact area between the pressing protrusion 7a and the first pressing groove 51 is not reduced, and the cutting insert 10 can be stably fixed.

[0043] 3, in this embodiment, the protrusion 6a of the upper jaw portion 3b is disposed in the first groove 41 of the cutting insert 10. The protrusion 6a is disposed at a position facing the inclined surface 41b of the first groove 41. It is preferable that the protrusion 6a and the inclined surface 41b are in contact with each other or are separated from each other with a small gap therebetween. When copy machining is performed using the indexable cutting tool 100, the cutting insert 10 is moved along the longitudinal direction of the holder 1. Therefore, a force acts on the cutting insert 10 in a direction to pull the cutting insert 10 out of the holder 1. Here, in this embodiment, since the protrusion 6a of the holder 1 is disposed in the first groove 41 of the cutting insert 10, even if a force acts on the cutting insert 10 in a direction to pull the cutting insert 10 out during copy machining, the protrusion 6a is caught on the inclined surface 41b of the first groove 41, and the position of the cutting insert 10 can be prevented from moving.

[0044] Therefore, according to this embodiment, it is possible to suppress the positional deviation of the cutting insert 10 during machining, and it is possible to stably perform a variety of types of machining including copy machining using the L-shaped cutting insert 10.

[0045] In this embodiment, the protrusion 6a provided on the holder 1 is a linear protrusion extending in a direction perpendicular to the extending direction of the second body portion 12 (the second direction d2 in the cutting insert). With this configuration, the area where the inclined surface 41b of the first groove 41 and the protrusion 6a face each other is increased, so that the protrusion 6a is more likely to be caught in the first groove 41. Since the cutting insert 10 can be more stably held in the insert mounting seat 8, the machining stability of the indexable cutting tool 100 can be further improved. The shape of the protrusion 6a is not limited to a linear protrusion, and may be, for example, a configuration consisting of a single or multiple dot-shaped protrusions.

[0046] (Modification) Hereinafter, a modified example of an indexable cutting tool will be described with reference to FIGS. 6A, 6B, and 7. FIG. Fig. 6A is a plan view showing a cutting insert 10A of a modified example as viewed from the first main surface 21 side. Fig. 6B is a plan view showing the cutting insert 10A of a modified example as viewed from the second main surface 22 side. Fig. 7 is a partial side view of a holder 1A of a modified example that holds the cutting insert 10A of a modified example. 6A, 6B and 7, the same components as those in Fig. 1 to 5 are denoted by the same reference numerals. In the following description, the description of the same components as those in the previous embodiment will be omitted as appropriate.

[0047] Fig. 6A corresponds to Fig. 2A in the previous embodiment, and Fig. 6B corresponds to Fig. 2C. As shown in Fig. 6A, in the cutting insert 10A of the modified example, the region on the second main body portion 12 in the first main surface 21 is a first pressed surface 61 consisting of a flat surface. As shown in Fig. 6B, in the cutting insert 10A, the region on the first main body portion 11 in the second main surface 22 is a second pressed surface 62 consisting of a flat surface.

[0048] 7, the holder 1A of the modified example has a pressing surface 7A made of a flat surface on the surface of the pressing part 6 facing the base part 4. A protrusion 6a is provided on the tip side of the pressing surface 7A.

[0049] In the indexable cutting tool of the modified example, the cutting insert 10A is fixed to the insert mounting seat 8 by pressing the pressing surface 7A of the holder 1A against the first pressed surface 61 and the second pressed surface 62 of the cutting insert 10A. Even when the first pressed surface 61 and the second pressed surface 62 contact the pressing surface 7A in the form of flat surface-to-flat surface contact as in this modified example, the cutting insert 10A can be firmly fixed to the insert mounting seat 8. The contact between the flat surfaces allows the relative positions of the first cutting edge 31 and the second cutting edge 32 of the cutting insert 10A with respect to the pressing surface 7A to be more accurately determined. [Explanation of symbols]

[0050] 1,1A…Holder 2…Shank 2b…Top surface 3…Head section 3a…Slit 3b...Maxillary part 3c…Mandibular part 3d…Connection part 4…Pedestal 5…Pedestal surface 5a...Support protrusion 6…Pressing part 6a…Protrusion 7,7A…Pressing surface 7a…Pressing protrusion 8…Insert mounting seat 9…Clamp screw 10, 10A…Cutting insert 11...First body part 41a, 41b, 42a, 42b, 51a, 51b, 52a, 52b...Slope 12...Second body part 13...Bend 31b, 32b...Scooping surface 21…First main surface 22…Second main surface 31…First cutting edge 31a, 32a…flank 32…Second cutting edge 41...First groove 42...Second concave groove 51...First pressing groove 52...Second pressing groove 61...first pressed surface 62...Second pressed surface 100…Replaceable cutting tools d1…first direction d2…Second direction d3…Third direction L1, L2...extension length

Claims

1. A cutting insert to be attached to an insert mounting seat of a holder for an indexable cutting tool, a rod-shaped first main body portion extending in a first direction; and a rod-shaped second main body portion connected to the first main body portion via a bent portion and extending in a second direction different from the first direction, When a surface on one side of the cutting insert as viewed from a third direction perpendicular to both the first direction and the second direction is defined as a first main surface, and a surface on the opposite side to the first main surface is defined as a second main surface, The first main surface has a first cutting edge located at a tip portion of the first body portion opposite the bent portion; A first groove extending along the first direction from a position closer to the bent portion than the first cutting edge and reaching a region on the bent portion; was established, The second main surface has A second cutting edge located at a tip portion of the second body portion opposite to the bent portion; A second groove extending along the second direction from a position closer to the bent portion than the second cutting edge and reaching a region on the bent portion; There is a system in place, The extension length of the first body portion from the bent portion and the extension length of the second body portion from the bent portion are the same. Cutting insert.

2. a first pressing groove extending along the second direction in a region of the first main surface on the second body portion; a second pressing groove extending along the first direction in a region of the second main surface on the first body portion; The cutting insert according to claim 1 .

3. A region of the first main surface on the second main body portion is a first pressed surface consisting of a flat surface, A region of the second main surface on the first main body portion is a second pressed surface consisting of a flat surface. The cutting insert according to claim 1 .

4. 2. An indexable cutting tool comprising: a holder having an insert mounting seat having a pressing surface and a seating surface opposed to each other; and the cutting insert according to claim 1, which is held by the insert mounting seat and has a pressed surface and a seating surface in contact with the pressing surface and the seating surface, respectively, The holder includes an upper jaw portion and a lower jaw portion that grip the cutting insert, the lower jaw portion has a seat surface on a surface facing the upper jaw portion, and the seat surface is provided with a support protrusion portion that fits into the first groove or the second groove of the cutting insert, The upper jaw portion has, on a surface facing the lower jaw portion, the pressing surface and a protrusion portion protruding toward the lower jaw portion and disposed in the second groove or the first groove at the bent portion. Indexable cutting tool.

5. 3. An indexable cutting tool comprising: a holder including an insert mounting seat having a pressing surface and a seating surface opposed to each other; and the cutting insert according to claim 2, which is held by the insert mounting seat and includes a pressed surface and a seating surface that are in contact with the pressing surface and the seating surface, respectively, The holder includes an upper jaw portion and a lower jaw portion that grip the cutting insert, the lower jaw portion has a seat surface on a surface facing the upper jaw portion, and the seat surface is provided with a support protrusion portion that fits into the first groove or the second groove of the cutting insert, the upper jaw portion has, on a surface facing the lower jaw portion, the pressing surface and a protrusion portion protruding toward the lower jaw portion and disposed in the second groove or the first groove located at the bent portion of the cutting insert, A pressing protrusion portion that fits into the second pressing groove or the first pressing groove of the cutting insert is provided on the pressing surface of the upper jaw portion. Indexable cutting tool.

6. 4. An indexable cutting tool comprising: a holder including an insert mounting seat having a pressing surface and a seating surface opposed to each other; and the cutting insert according to claim 3, which is held by the insert mounting seat and includes a pressed surface and a seating surface that are in contact with the pressing surface and the seating surface, respectively, The holder includes an upper jaw portion and a lower jaw portion that grip the cutting insert, the lower jaw portion has a seat surface on a surface facing the upper jaw portion, and the seat surface is provided with a support protrusion portion that fits into the first groove or the second groove of the cutting insert, the upper jaw portion has, on a surface facing the lower jaw portion, the pressing surface and a protrusion portion protruding toward the lower jaw portion and disposed in the second groove or the first groove located at the bent portion of the cutting insert, The pressing surface of the upper jaw portion is a flat surface that presses the second pressed surface or the first pressed surface of the cutting insert, Indexable cutting tool.

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