Cutting inserts, cutting tools

Abstract

To provide a cutting insert that allows for easy replacement while suppressing misalignment of the cutting edge. [Solution] A cutting insert comprising a roughly diamond-shaped insert body, a rake face facing the thickness direction of the insert body, a relief face formed on the peripheral wall of the insert body corresponding to the acute-angled corner of the rake face and intersecting the rake face, a cutting edge forming the intersecting ridge line of the rake face and the relief face of the insert body, and a mounting hole penetrating the insert body in the thickness direction. The apex angle of the acute-angled corner of the rake face is 20° or more and 35° or less. The peripheral wall of the insert body has a projection that partially protrudes outward at the obtuse-angled corner of the rake face. The projection has a projection restraining surface consisting of a flat surface that extends in a direction intersecting the rake face on the surface facing the cutting edge direction.

Description

Technical Field

[0001] The present invention relates to a cutting insert and a cutting tool.

Background Art

[0002] Conventionally, as a tool for copying machining, a profile bite using a diamond-shaped cutting insert having an apex angle of about 25° has been known. In this type of cutting tool, since the distance from the screwing position of the cutting insert to the cutting edge is large, displacement of the cutting edge is likely to occur due to rotation of the cutting insert caused by cutting load. In order to suppress such displacement of the cutting edge, a structure in which the cutting insert is screwed and then tightened and fixed with a clamp piece (see Patent Document 1), or a structure in which the cutting insert is fixed with a plurality of screws (see Patent Document 2) has been adopted.

Prior Art Literature

Patent Literature

[0003]

Patent Document 1

Patent Document 2

Summary of the Invention

Problem to be Solved by the Invention

[0004] However, when a plurality of clamping members are used to suppress displacement of the cutting edge of the cutting insert, there has been a problem that replacement work of the cutting insert becomes complicated.

Means for Solving the Problem

[0005] According to one aspect of the present invention, the following configuration is disclosed.

[0006] (1) A cutting insert comprising: an insert body in the shape of a roughly rhombic plate; a rake face facing the thickness direction of the insert body; a relief face formed on the peripheral wall of the insert body corresponding to the acute-angled corner of the rake face and intersecting the rake face; a cutting edge forming the intersecting ridge line of the rake face and the relief face of the insert body; and a mounting hole penetrating the insert body in the thickness direction, wherein the apex angle of the acute-angled corner of the rake face is 20° or more and 35° or less; the peripheral wall of the insert body has a projection that partially protrudes outward at the obtuse-angled corner of the rake face; and the surface of the projection facing the cutting edge direction has a projection restraining surface consisting of a flat surface that extends in a direction intersecting the rake face.

[0007] (2) In (1), the projection may be substantially triangular in shape when viewed from above of the insert body, and the projection may have two side surfaces that constrain the projection.

[0008] (3)(2) The vertex angle of the tip of the substantially triangular projection in the direction of protrusion may be an acute angle.

[0009] (4)(1) The insert body has a recess on each of the four peripheral walls that is recessed inward from the relief surface located at the acute corner of the rake face, the projection is a portion that protrudes outward relative to the peripheral wall by the two recesses that sandwich the obtuse corner of the rake face, and the projection restraining surface may be located on the inner surface of the recess facing the cutting edge direction.

[0010] In (5)(4), the opening angle of the two projection restraining surfaces facing a common cutting edge, as seen from the cutting edge, may be 180° or less.

[0011] In (6)(4), the configuration may be such that the opening angle of the two projection restraining surfaces facing a common cutting edge, as seen from the cutting edge, is greater than 180°.

[0012] (7) In any one of (1) to (6), the opening angle (β) of the projection restraint surface may be greater than the apex angle (α) of the acute-angled corner of the rake face.

[0013] (8) A cutting tool comprising the above-mentioned cutting insert and a tool body having an insert mounting seat for holding the cutting insert, wherein the insert mounting seat has an inner wall surface that contacts two circumferential wall surfaces that sandwich the acute-angled corner of the rake face of the cutting insert, and a tip surface that contacts the projection restraining surface formed on the projection of the cutting insert. [Effects of the Invention]

[0014] According to one aspect of the present invention, a cutting insert that can be fixed to a holder without using multiple clamping members, and a cutting tool that allows for easy replacement of the cutting insert are provided. [Brief explanation of the drawing]

[0015] [Figure 1] Figure 1 is a perspective view of the tip portion of the replaceable-tip cutting tool according to the first embodiment. [Figure 2] Figure 2 is a perspective view of the cutting insert according to the first embodiment. [Figure 3] Figure 3 is a partial plan view of the first embodiment of an interchangeable-tip cutting tool. [Figure 4] Figure 4 is a perspective view of the tip portion of the replaceable-tip cutting tool according to the second embodiment. [Figure 5] Figure 5 is a perspective view of the cutting insert according to the second embodiment. [Figure 6] Figure 6 is a partial plan view of an indexable cutting tool according to the second embodiment. [Figure 7] Figure 7 is a perspective view of the cutting insert of the third embodiment. [Figure 8] Figure 8 is a partial plan view of an indexable cutting tool according to the third embodiment. [Modes for carrying out the invention]

[0016] (First Embodiment) Figure 1 is a perspective view of a tip portion of a indexable cutting tool according to a first embodiment. Figure 2 is a perspective view of a cutting insert according to the first embodiment. Figure 3 is a partial plan view of the indexable cutting tool according to the first embodiment.

[0017] The cutting insert 1 and the indexable cutting tool 10 of the present embodiment are tools for performing turning on a work material made of a metal material or the like, and are used for, for example, finish cutting such as copying and spherical machining, and medium cutting.

[0018] As shown in Figure 1, the indexable cutting tool 10 comprises: a tool body 11 made of a shaft-shaped steel material or the like, having a recessed insert mounting seat 12 formed at a tip end thereof; and a rhombic plate-shaped cutting insert 1 made of a hard material such as cemented carbide, which is detachably mounted to the insert mounting seat 12.

[0019] The tool body 11 has a rectangular parallelepiped shank portion 13a and a head portion 13b located at a tip end in a direction in which the shank portion 13a extends. In the indexable cutting tool 10, the shank portion 13a is fixedly supported by a machine tool (not shown) in a state where a cutting edge 6 of the cutting insert 1 mounted to a tip portion of the tool body 11 protrudes toward the work material.

[0020] In a top view of the tool body 11, a width of the head portion 13b of the tool body 11 is larger than a width of the shank portion 13a. Specifically, the head portion 13b of the tool body 11 is formed to protrude more than the shank portion 13a toward one side in the width direction. In addition, the width of the head portion 13b of the tool body 11 gradually narrows toward the tip side along the extending direction of the tool body 11. Specifically, a surface facing the other side in the width direction among the tip portion of the tool body 11 is formed to be inclined so as to gradually retract toward one side in the width direction as it goes toward the tip side of the tool body 11.

[0021] The insert mounting seat 12 has a rhomboid-shaped bottom surface 12A facing upward in the height direction, a pair of inner wall surfaces 12B formed to sandwich the triangular portion of the bottom surface 12A located on the base end side of the tool body 11 from the width direction, and arranged in an acute-angled concave V shape when viewed from the front of the bottom surface 12A (in a top view of the tool body 11), and a tip surface 12C that is continuous with the tips of each of the two inner wall surfaces 12B and faces the tip side of the tool body 11. When the cutting insert 1 is mounted on the insert mounting seat 12, the two inner wall surfaces 12B are each positioned facing the flat surface 19 (see Figure 3) of the cutting insert 1, which will be described later, while being spaced apart from the cutting edge 6. The two tip surfaces 12C of the insert mounting seat 12 can be pressed against the projection restraint surfaces 20a and 20b (see Figure 3) of the cutting insert 1, which will be described later.

[0022] The bottom surface 12A of the insert mounting seat 12 has a female screw hole (not shown) into which a clamp screw 15 for attaching the cutting insert 1 to the insert mounting seat 12 is tightened. The insert mounting seat 12 is located at one end in the width direction of the head portion 13b of the tool body 11 and opens toward the upper and tip sides in the height direction of the tool body 11.

[0023] Of the head portion 13b of the tool body 11, the portion located below the insert mounting seat 12 in the height direction is formed to be inclined so as it moves downward, it gradually recedes towards the base end of the tool body 11. Furthermore, of the head portion 13b of the tool body 11, the portion located below the insert mounting seat 12 in the height direction is formed so as it moves towards the tip end of the tool body 11, its width gradually narrows.

[0024] As shown in Figures 1 and 2, the cutting insert 1 comprises a diamond-shaped insert body 2, a rake face 3 facing the thickness direction of the insert body 2, a relief face 5 formed on the peripheral wall of the insert body 2 to correspond to the acute-angled corner 3A of the rake face 3 and intersecting the rake face 3, a cutting edge 6 forming the intersecting ridge line between the rake face 3 and the relief face 5 of the insert body 2, and a mounting hole 7 formed through the insert body 2 in the thickness direction.

[0025] The rake face 3 is formed on one of the two outer surfaces of the insert body 2 that face in the thickness direction. At the four corners of the rake face 3, two acute-angled corners 3A and one obtuse-angled corner 3B are formed, positioned opposite each other with respect to the center of the rake face 3 (the part where the mounting hole 7 opens).

[0026] The cutting insert 1 has projections 8a and 8b on the peripheral wall of the obtuse-angled corner 3B of the rake face 3, projecting outward from the obtuse-angled corner 3B. In this embodiment, because projections 8a and 8b are formed on the two obtuse-angled corners 3B of the rake face 3, the rake face 3 as a whole has a cross shape.

[0027] As shown in Figures 2 and 3, projection 8a has two projection restraining surfaces 20a, which are flat surfaces extending in a direction intersecting the relief surface 5 of the cutting edge, on two faces facing the cutting edge direction. Projection 8b has two projection restraining surfaces 20b, which are flat surfaces extending in a direction intersecting the rake surface 3, on two faces facing the cutting edge direction.

[0028] In this specification, the corners of the rake face 3 where the protrusions 8a and 8b are provided are referred to as the "obtuse-angled corners." This is because the insert body 2 of the cutting insert 1 corresponds to a configuration in which the protrusions 8a and 8b are provided at the obtuse-angled corners of a conventional rhombic plate-shaped insert body. Furthermore, in the following explanation, as shown in Figures 2 and 3, the direction connecting the pair of acute corners 3A is referred to as the longitudinal direction LD of the rake face 3, and the direction connecting the pair of obtuse corners 3B is referred to as the short direction SD of the rake face 3.

[0029] Of the two outer surfaces facing the thickness direction in the insert body 2, the other surface facing away from the rake face 3 is a cross-shaped seating surface 9 with a smaller outer diameter (area) than the rake face 3.

[0030] A cutting edge 6 is formed on the outer edge of the rake face 3, in the portion corresponding to the acute-angled corner 3A. In this embodiment, when the rake face 3 is viewed from the front, the apex angle α of the acute-angled corner 3A of the rake face 3 is 25°. The apex angle of the acute-angled corner 3A is in the range of 20° to 35°.

[0031] The mounting hole 7 is formed by opening into the central portion 3a of the rake face 3 and the seating surface 9. In the mounting hole 7, the inner diameter of the portion that opens into the central portion 3a of the rake face 3 is larger than the inner diameter of the portion that opens into the seating surface 9. The cutting insert 1 is rotationally symmetric about the central axis of the mounting hole 7. Specifically, the cutting insert 1 is formed with two-fold symmetry (180° symmetry) about the central axis of the mounting hole 7.

[0032] A flat surface 19 is formed in the peripheral wall of the insert body 2, in the region between the protrusions 8a and 8b and the acute-angled corner 3A. The flat surface 19 is formed in the peripheral wall of the insert body 2, excluding the relief surface 5 portion located on the rake face 3 side in the thickness direction at both ends of the longitudinal direction LD of the rake face 3. The flat surface 19 intersects the rake face 3 at the end on the rake face 3 side along the thickness direction, and intersects the seating surface 9 at the end on the seating surface 9 side along the thickness direction. Furthermore, the flat surface 19 is inclined to gradually recede inward towards the peripheral wall of the insert body 2 as it moves toward the seating surface 9 side along the thickness direction.

[0033] The projections 8a and 8b are formed on both sides of the rake face 3 in the short direction relative to the central portion 3a. When viewing the rake face 3 from the front, the projections 8a and 8b are approximately isosceles triangles, becoming narrower as they move away from the central portion 3a in the short direction. In this embodiment, the vertex angles of the projections 8a and 8b are 50°. The vertex angles of the projections 8a and 8b may be acute or obtuse. If the vertex angles of the projections 8a and 8b are acute, the sides of the projections 8a and 8b face more toward the cutting edge, making it easier to obtain the rotation suppression effect of the cutting insert 1 by the projections 8a and 8b.

[0034] The projection 8a has two projection restraint surfaces 20a that each face the two cutting edges of the insert body 2. The projection 8b has two projection restraint surfaces 20b that each face the two cutting edges of the insert body 2. The projection restraint surfaces 20a and 20b each consist of flat surfaces that extend in a direction intersecting the rake face 3.

[0035] The two projection restraint surfaces 20a and 20b, which face a common cutting edge, are inclined at the same angle with respect to the longitudinal direction LD. In this embodiment, the projection restraint surfaces 20a and 20b intersect with respect to the longitudinal direction LD at 65°. That is, the opening angle β of the two projection restraint surfaces 20a and 20b as seen from the common cutting edge is 130°. The opening angle β of the projection restraint surfaces 20a and 20b described above is just an example and can be changed as appropriate as long as the function of the projection restraint surfaces 20a and 20b is not impaired. The opening angle β can be set to an angle greater than the apex angle α (20° to 35°) of the acute-angled corner 3A and less than 180°. For example, the opening angle β can be set in the range of 60° to 170°.

[0036] The cutting insert 1 is positioned on the insert mounting seat 12 of the tool body 11 and fastened to the tool body 11 by a clamp screw 15 inserted into the mounting hole 7. With the cutting insert 1 mounted on the tool body 11, the flat surface 19 of the cutting insert 1 and the inner wall surface 12B of the insert mounting seat 12 face each other in a non-contact state. The bottom surface 12A of the insert mounting seat 12 is pressed against the seating surface 9 of the cutting insert 1. The two tip surfaces 12C of the insert mounting seat 12 are pressed against the projection restraint surfaces 20a and 20b, respectively.

[0037] When a cutting force is applied to the cutting edge of the cutting insert 1 during machining, a force acts on the cutting insert 1 that rotates it around the axis of the clamp screw 15. In the case of a rhombic cutting insert, it is unavoidable that a gap will occur between the restraining surface of the peripheral wall connected to the relief surface and the inner wall of the insert mounting seat, so it will rotate slightly due to the action of the cutting force. Furthermore, in the case of an elongated rhombic cutting insert with an apex angle of about 25°, the length from the clamp screw to the cutting edge is large, so even a slight rotation will cause the cutting edge to move significantly.

[0038] Therefore, in the replaceable-tip cutting tool 10 of this embodiment, a cutting insert 1 having protrusions 8a and 8b is used, and the cutting insert 1 is restrained by pressing the protrusions 8a and 8b against the tip surface 12C of the insert mounting seat 12. With this configuration, when a rotational force caused by the cutting force acts on the cutting insert 1, the projection restraining surface 20a of the protrusion 8a or the projection restraining surface 20b of the protrusion 8b abuts against the tip surface 12C of the insert mounting seat 12. This suppresses the rotation of the cutting insert 1. Therefore, displacement of the cutting edge of the cutting insert 1 during machining can be suppressed, and excellent machining accuracy can be obtained. In particular, it can be suitably used for "copy machining" in which cutting forces act on the cutting edge of the cutting insert 1 from all directions.

[0039] In this embodiment, the cutting insert 1 and the replaceable-tip cutting tool 10 have rotational suppression effects from the projections 8a and 8b, which suppress misalignment of the cutting edge of the cutting insert 1. Therefore, there is no need to provide separate clamp pieces or screws for rotational suppression. In other words, in this embodiment, the cutting insert 1 is installed simply by placing it on the insert mounting seat 12 of the tool body 11 and tightening the clamp screw 15. Thus, in this embodiment, the replaceable-tip cutting tool 10 allows for easy and quick replacement of the cutting insert 1.

[0040] (Second Embodiment) Figure 4 is a perspective view of the tip portion of the indexable cutting tool of the second embodiment. Figure 5 is a perspective view of the cutting insert of the second embodiment. Figure 6 is a partial plan view of the indexable cutting tool of the second embodiment.

[0041] The following describes the cutting insert 1A of the second embodiment and the replaceable-tip cutting tool 10 equipped therewith. In the following description, components common to the first embodiment are denoted by the same reference numerals, and their detailed descriptions are omitted as appropriate.

[0042] As shown in Figures 4 to 6, the replaceable tip cutting tool 10 of the second embodiment includes a cutting insert 1A. The cutting insert 1A includes an insert body 2, a rake face 3, a relief face 5, a cutting edge 6, a mounting hole 7, projections 8a and 8b, and recesses 21a and 21b.

[0043] In the cutting insert 1A of this embodiment, recesses 21a and 21b are formed on the four peripheral wall surfaces of the insert body 2, recessing inward from the relief surface 5 located at the acute-angled corner 3A of the rake face 3. The projection 8a is located between the two recesses 21a, 21a that sandwich one obtuse-angled corner 3B of the rake face 3. The projection 8a is a portion that protrudes relatively outward from the peripheral wall due to the formation of the two recesses 21a. The projection 8b is located between the two recesses 21b that sandwich the other obtuse-angled corner 3B of the rake face 3. The projection 8b is a portion that protrudes relatively outward from the peripheral wall due to the formation of the two recesses 21b. The projections 8a and 8b are formed on both sides in the short-side direction relative to the central portion 3a of the rake face 3. When the rake face 3 is viewed from the front, the projections 8a and 8b have the same shape as the obtuse-angled corners of the rhombus.

[0044] On the two sides of the projection 8a facing the cutting edge, projection restraint surfaces 22a are formed, each consisting of a flat surface extending in a direction intersecting the rake face 3. The projection restraint surfaces 22a are formed on the inner side of the recess 21a facing the cutting edge. Similarly, projection restraint surfaces 22b are formed on the two sides of the projection 8b facing the cutting edge. The projection restraint surfaces 22b are formed on the inner side of the recess 21b facing the cutting edge.

[0045] A flat surface 19 is formed on the bottom surface of the recesses 21a and 21b, extending in a direction intersecting the scoop surface 3. The flat surface 19 intersects the scoop surface 3 at its end on the scoop surface 3 side along the thickness direction, and intersects the seating surface 9 at its end on the seating surface 9 side along the thickness direction. In this embodiment, the flat surface 19 is a vertical surface extending in a direction parallel to the thickness direction. The flat surface 19 may be inclined to gradually recede inward towards the peripheral wall of the insert body 2 as it moves toward the seating surface 9 side along the thickness direction.

[0046] The projection restraint surfaces 22a and 22b each consist of flat surfaces extending in a direction intersecting the rake face 3. The two projection restraint surfaces 22a and 22b facing the common cutting edge are inclined at the same angle with respect to the longitudinal direction LD. In this embodiment, the projection restraint surfaces 22a and 22b intersect the longitudinal direction LD at 65°. That is, the opening angle β of the two projection restraint surfaces 22a and 22b as seen from the common cutting edge is 130°. The opening angle β of the projection restraint surfaces 22a and 22b in this embodiment is an example of a configuration where the opening angle is 180° or less, and can be changed as appropriate as long as the function of the projection restraint surfaces 22a and 22b is not impaired. The opening angle β can be set to an angle greater than the apex angle α (20° to 35°) of the acute-angled corner 3A and less than or equal to 180°. For example, the opening angle β can be set in the range of 60° to 180°.

[0047] The cutting insert 1A is positioned on the insert mounting seat 12 of the tool body 11 and fastened to the tool body 11 by a clamp screw 15 inserted into the mounting hole 7. With the cutting insert 1A mounted on the tool body 11, the flat surface 19 of the cutting insert 1A and the inner wall surface 12B of the insert mounting seat 12 face each other in a non-contact state. The bottom surface 12A of the insert mounting seat 12 is pressed against the seating surface 9 of the cutting insert 1A. The two tip surfaces 12C of the insert mounting seat 12 are pressed against the projection restraint surfaces 22a and 22b.

[0048] In the replaceable-tip cutting tool 10 of this embodiment, when a rotational force due to the cutting force acts on the cutting insert 1A, the projection restraining surface 22a of the projection 8a or the projection restraining surface 22b of the projection 8b abuts against the tip surface 12C of the insert mounting seat 12. This suppresses the rotation of the cutting insert 1A. Therefore, displacement of the cutting edge of the cutting insert 1A during machining can be suppressed, and excellent machining accuracy can be obtained. In particular, it can be suitably used for "copy machining" in which cutting forces act on the cutting edge of the cutting insert 1A from all directions. Furthermore, in the replaceable-tip cutting tool 10 of this embodiment, the cutting insert 1A can be replaced by attaching and detaching a single clamp screw 15, thus enabling the replacement of the cutting insert 1 to be performed easily and quickly.

[0049] (Third embodiment) Figure 7 is a perspective view of a cutting insert according to the third embodiment. Figure 8 is a partial plan view of an indexable cutting tool according to the third embodiment.

[0050] The following describes the cutting insert 1B of the third embodiment and the replaceable-tip cutting tool 10 equipped therewith. The third embodiment is configured such that the opening angle β of the projection restraining surfaces 22a and 22b of the second embodiment is greater than 180°. Therefore, in the following description, components common to the second embodiment are denoted by the same reference numerals, and their detailed descriptions are omitted as appropriate.

[0051] As shown in Figures 7 and 8, the replaceable tip cutting tool 10 of the third embodiment includes a cutting insert 1B. The cutting insert 1B includes an insert body 2, a rake face 3, a relief face 5, a cutting edge 6, a mounting hole 7, projections 8a and 8b, a flat surface 19, recesses 21a and 21b, and projection restraining surfaces 22a and 22b.

[0052] In the cutting insert 1B of this embodiment, the two projection restraint surfaces 22a and 22b facing the common cutting edge are inclined at the same angle with respect to the longitudinal direction LD. In this embodiment, the projection restraint surfaces 22a and 22b intersect the longitudinal direction LD at 102.5°. That is, the opening angle β of the two projection restraint surfaces 22a and 22b as seen from the common cutting edge is 205°. In this embodiment as well, the opening angle β of the projection restraint surfaces 22a and 22b can be changed as appropriate, as long as the function of the projection restraint surfaces 22a and 22b is not impaired. The opening angle β can be set to an angle greater than 180°, but the range that does not impair the function of the projection restraint surfaces 22a and 22b is, for example, 240° or less.

[0053] With the cutting insert 1B mounted on the tool body 11, the projection restraint surfaces 22a and 22b are pressed against the two tip surfaces 12C of the insert mounting seat 12. In this embodiment, the projection restraint surfaces 22a and 22b are oriented more toward the cutting edge compared to the second embodiment. As a result, when a rotational force due to the cutting force acts on the cutting insert 1B, the direction in which the projection restraint surface 22a of projection 8a or the projection restraint surface 22b of projection 8b abuts against the tip surface 12C of the insert mounting seat 12 is closer to the tangential direction of the rotational motion. Consequently, the effect of suppressing the rotation of the cutting insert 1B is greatly increased, and excellent machining accuracy can be obtained. In particular, it can be suitably used for "copy machining" where cutting forces act on the cutting edge of the cutting insert 1B from all directions. Furthermore, in the replaceable-tip cutting tool 10 of this embodiment, the cutting insert 1B can be replaced by attaching and detaching a single clamping screw 15, thus enabling the replacement of the cutting insert 1 to be performed easily and quickly. [Explanation of symbols]

[0054] 1, 1A, 1B… Cutting inserts 2… Insert body 3... Scoop surface 3a...Central part 3A... The corner on the acute side 3B... Obtuse angle corner 5,5a...Escape side 6…Cutting edge 7…Mounting holes 8a, 8b…Protrusion 9…Seat surface 10… Replaceable tip cutting tools 11...Tool body 12…Insert mounting seat 12A...bottom 12B...Inner wall surface 12C…Tip surface 13a... Shank 13b... Head section 15… Clamp screw 19...Flat surface 20a, 20b, 22a, 22b…Protrusion restraining surface 21a, 21b… recessed LD...longitudinal direction SD...short direction α… Vertex angle β...Opening angle

Claims

1. A roughly diamond-shaped insert body, The rake surface of the insert body facing the thickness direction, A relief surface is formed on the peripheral wall of the insert body corresponding to the acute-angled corner of the rake face, and intersects the rake face. The cutting edge forming the intersecting ridge between the rake face and the relief face of the insert body, The insert body comprises a mounting hole that penetrates in the thickness direction, The apex angle of the acute-angled corner of the rake face is 20° or more and 35° or less. The rake face has a projection at the obtuse-angled corner where the peripheral wall of the insert body partially protrudes outward. The projection has a projection restraining surface on the surface facing the cutting edge direction, which is a flat surface extending in a direction intersecting the rake surface. Cutting insert.

2. The projection is substantially triangular in plan view of the insert body, and has two side surfaces that constrain the projection. The cutting insert according to claim 1.

3. The apex angle of the tip of the aforementioned roughly triangular projection in the direction of protrusion is acute. The cutting insert according to claim 2.

4. The insert body has a recess on each of its four peripheral walls that is recessed inward from the relief surface located at the acute corner of the rake face, The aforementioned projection is a portion that protrudes relatively outward from the peripheral wall by the two recesses that sandwich the obtuse-angled corner of the rake face, The aforementioned projection restraining surface is located on the inner surface of the recess facing the cutting edge direction, The cutting insert according to claim 1.

5. The opening angle of the two projection restraining surfaces, which face a common cutting edge, as viewed from the cutting edge, is 180° or less. The cutting insert according to claim 4.

6. The opening angle of the two aforementioned restraining surfaces of the protrusions, which face a common cutting edge, as viewed from the cutting edge, is greater than 180°. The cutting insert according to claim 4.

7. The opening angle (β) of the projection restraining surface is greater than the apex angle (α) of the acute-angled corner of the rake face. A cutting insert according to any one of claims 1 to 6.

8. A cutting insert according to claim 1, A tool body having an insert mounting seat for holding the cutting insert, Equipped with, The insert mounting seat has an inner wall surface that contacts two circumferential wall surfaces that sandwich the acute-angled corner of the rake face of the cutting insert, and a tip surface that contacts the projection restraining surface formed on the projection of the cutting insert. cutting tools.

Images