JP6493510B1 - Cutting insert - Google Patents

Abstract

A cutting insert capable of being firmly fixed to a tool body is provided.
A cutting insert includes a first end face, a second end face facing the first end face, a peripheral side face connecting the first end face and the second end face, and a first end face. A cutting edge 12 is provided at a crossing ridge line portion between the outer peripheral surface 30 and the peripheral side surface 30, and the cutting edge 12 is provided on the long side portion 11 a side of the first end surface 10, and has an uneven shape when viewed from the direction facing the first end surface 10. And a corner cutting edge 12b connected to the waveform cutting edge 12a, and the inclination angle of the rake face 10a corresponding to the corner cutting edge 12b is a rake face corresponding to the waveform cutting edge 12a. The inclination angle is smaller than 10a.
[Selection] Figure 1

Description

  The present invention relates to a cutting insert.

  There is known a rotary cutting tool in which a cutting insert having a cutting edge is mounted on a tool body that rotates around an axis. For example, Patent Document 1 discloses this cutting insert.

  The cutting insert of patent document 1 is fundamentally comprised from the two end surfaces which mutually oppose, and the surrounding side surface which exists between these end surfaces. In Patent Document 1, of two end faces facing each other, one face facing the thickness direction of the insert body is a rake face, and a side face arranged around the rake face is a flank face. A cutting edge is formed at the intersection ridge line portion between the rake face and the flank face, and a concave portion is formed on the flank face so that the cutting edge is divided into a plurality of portions. According to Patent Document 1, by having the cutting blades divided in this way, it is possible to generate chips cut by one type of cutting insert.

JP 2012-152867 A

  As in Patent Document 1, when machining is performed with a rotary cutting tool using a cutting insert in which a cutting edge is divided, vibration may occur during the machining. When this vibration occurs, the cutting edge may be easily chipped. In Patent Document 1, no study has been made on a specific structure for suppressing chipping of the cutting edge, and it has been necessary to improve the structure.

  Then, an object of this invention is to provide the cutting insert which can aim at the lifetime improvement of a cutting edge in the cutting insert which has the divided | segmented cutting edge.

  The cutting insert which concerns on 1 aspect of this invention is equipped with a 1st end surface, the 2nd end surface facing this 1st end surface, and the surrounding side surface which connects a 1st end surface and a 2nd end surface, A 1st end surface and a circumference | surroundings It is a cutting insert which has a cutting edge in a crossing ridgeline part with a side, Comprising: When it sees from the direction which opposes the 1st end face, the 1st end face comprises a pair of long sides and a pair of short sides It has a substantially rectangular shape, and the cutting edge is provided on the pair of long side portions, and has a corrugated cutting edge that exhibits an uneven shape when viewed from the direction facing the first end face, and a corner cutting connected to the corrugating cutting edge And a rake face inclination angle corresponding to the corner cutting edge is smaller than a rake face inclination angle corresponding to the corrugated cutting edge.

  According to the knowledge found by the present inventors, it is a substantially quadrangular cutting insert when viewed from the direction facing the first end surface, and has a corrugated waveform located on the long side of the first end surface. It has been found that when a cutting insert having a cutting edge and a corner cutting edge connected to the corrugated cutting edge is used, the corner cutting edge side tends to chip. Based on the knowledge found by the present inventors, the cutting insert according to the present invention has a configuration in which the rake angle of the rake face corresponding to the corner cutting edge is smaller than the inclination angle of the rake face corresponding to the corrugated cutting edge. ing. According to this configuration, the strength of the corner cutting edge can be increased. As a result, chipping on the corner cutting edge side can be suppressed, and the life of the cutting edge can be extended.

  In the above aspect, the mounting hole is formed so as to penetrate the first end face and the second end face, and the cutting edge further includes an inner cutting edge located between the corrugated cutting edge and the corner cutting edge, Assuming a first virtual plane that passes through the mounting hole and is perpendicular to the axis of the mounting hole, the rake face corresponding to the corner cutting edge is relative to the first virtual plane when viewed in the cross-section in the thickness direction of the cutting insert. Assuming a second imaginary plane that is located on the lower side and passes through the inner cutting edge and is perpendicular to the axis, the rake face corresponding to the inner cutting edge is viewed in a cross section in the thickness direction of the cutting insert. Alternatively, it may be located above the second virtual plane.

  In the above aspect, the inner cutting edge may be configured by combining linear cutting edges.

  In the above aspect, the flank corresponding to the inner cutting edge may protrude in the longitudinal direction of the cutting insert and away from the axis with respect to the flank corresponding to the corner cutting edge.

  In the above aspect, the inclination angle of the rake face corresponding to the corner cutting edge is determined from the connecting portion between one end of the corner cutting edge and one end of the corrugated cutting edge, and the other end and the inner cutting edge on the opposite side of one end of the corner cutting edge. It may decrease as it goes to the connection part with one end of the.

  In the above aspect, the corner cutting edge is configured by combining the first arc and the second arc having different curvature radii, and the curvature radius of the first arc connected to one end of the corrugated cutting edge is continuous with the first arc. It may be smaller than the radius of curvature of the two arcs.

  In the above aspect, the inclination angle of the flank corresponding to the first arc may be smaller than the angle of the flank corresponding to the second arc.

  In the above aspect, when viewed in a cross section in the thickness direction of the cutting insert, the flank corresponding to the corrugated cutting edge may be configured by connecting three surfaces having different inclination angles.

  In the above aspect, the flank corresponding to the corrugated cutting edge is provided with a plurality of abutting surfaces that abut against the wall surface of the insert mounting seat of the tool body to which the cutting insert is attached. It may be decreased from the connecting portion with the corner cutting edge toward the connecting portion between the corrugated cutting edge and the inner cutting edge adjacent to the corrugated cutting edge.

  ADVANTAGE OF THE INVENTION According to this invention, in the cutting insert which has the divided | segmented cutting edge, the cutting insert which can aim at the lifetime improvement of a cutting edge can be provided.

It is a perspective view which shows schematic structure of the cutting insert in this embodiment. It is a front view of the cutting insert shown in FIG. It is a rear view of the cutting insert shown in FIG. It is the side view seen from the long side direction of the cutting insert shown in FIG. It is the side view seen from the short side direction of the cutting insert shown in FIG. It is VI-VI sectional drawing in FIG. It is VII-VII sectional drawing in FIG. It is VIII-VIII sectional drawing in FIG. It is IX-IX sectional drawing in FIG. It is XX sectional drawing in FIG. It is XI-XI sectional drawing in FIG. FIG. 3 is an enlarged view of a circle X in FIG. 2. It is an enlarged side view which expands and shows the front-end | tip part of the cutting insert shown in FIG. It is a perspective view which shows schematic structure of a rotary cutting tool. It is the side view which looked at the rotary cutting tool shown in FIG. 14 from the front end side. It is a perspective view which shows schematic structure of a tool body. It is the side view which looked at the tool body shown in FIG. 16 from the front end side.

  Embodiments of the present invention will be described below with reference to the accompanying drawings. The dimensions, shapes, angles, etc. of the drawings may differ from the actual dimensions, shapes, angles, etc. Therefore, the technical scope of the present invention is not limited to the size, shape, angle, and the like of each part shown in these drawings.

  The configuration of the cutting insert 1 according to the present embodiment will be described with reference to FIGS. FIG. 1 is a perspective view showing a schematic configuration of the cutting insert 1. FIG. 2 is a front view of the cutting insert 1 shown in FIG. FIG. 3 is a rear view of the cutting insert 1 shown in FIG. FIG. 4 is a side view of the cutting insert 1 shown in FIG. 1 viewed from the long side direction. FIG. 5 is a side view of the cutting insert 1 shown in FIG. 1 viewed from the short side direction.

  As shown in FIGS. 1 to 5, the cutting insert 1 is configured in a substantially rectangular plate shape. The cutting insert 1 includes a first end surface 10 having a substantially rectangular shape, a second end surface 20 disposed so as to face the first end surface 10, and a peripheral side surface 30 that connects the first end surface 10 and the second end surface 20. And basically consists of. A mounting hole 5 in which a central axis O is defined is formed so as to pass through a substantially central portion of the first end surface 10 and a substantially central portion of the second end surface 20. The cutting insert 1 is configured to be 180 ° rotationally symmetrical around the central axis O. In the present embodiment, the central axis O is the central axis of the cutting insert 1, and the central axis of the cutting insert 1 and the central axis of the mounting hole 5 coincide, but the present invention is not limited to this.

  The cutting insert 1 of the present embodiment has a longer side (length in the left-right direction in FIG. 2) larger than a width on the shorter side (up-down direction in FIG. 2), and around the central axis O. However, the present invention is not limited to this example. The cutting insert 1 of the present embodiment may have another shape such as a triangular shape or a pentagonal shape, for example.

  The first end face 10 is a substantially quadrangular shape composed of four sides (two long sides 11a and two short sides 11b) when viewed from the direction facing the first end 10 (that is, in FIG. 2). Presents. The two long side portions 11a are opposed to each other, and the two short side portions 11b are also arranged to face each other.

  As shown in FIGS. 4 and 5, the peripheral side surface 30 is adjacent to the first side surface portion 30 a adjacent to the long side portion 11 a of the first end surface 10 and the short side portion 11 b of the first end surface 10. A second side surface portion 30b and a third side surface portion 30c.

  A plurality of cutting edges are formed at the intersecting ridge line portion between the first end surface 10 and the peripheral side surface 30. In the present embodiment, the plurality of cutting edges include a pair of corrugated cutting edges 12a, a pair of corner cutting edges 12b, and a pair of inner cutting edges 12c. The corrugated cutting edge 12a is formed across the intersecting ridge line portion corresponding to the pair of long side portions 11a (that is, the intersecting ridge line portion between the first end surface 10 and the first side surface portion 30a). The corner cutting edge 12b and the inner cutting edge 12c are crossed ridge lines corresponding to the pair of short sides 11b (that is, the first end face 10 and the side face on the short side (second side face 30b and third side face 30c). And the crossing ridge part). As shown in FIG. 2, the plurality of cutting edges in the present embodiment are configured such that a corrugated cutting edge 12 a, a corner cutting edge 12 b, and an inner cutting edge 12 c are continuously connected in this order. Hereinafter, the corrugated cutting edge 12a, the corner cutting edge 12b, and the inner cutting edge 12c are collectively referred to as the cutting edge 12.

  As shown in FIG. 2, a part of the cutting edge 12 is divided into a plurality of cutting edges. Specifically, the virtual contour R indicating the contour of the shape in which the cutting edge is not divided into a plurality of cutting edges (in other words, when the corrugated cutting edge 12a shown in FIG. 2 is assumed to be a straight cutting edge). As a result, a plurality of concave portions C that are recessed from the virtual contour line R are formed in the first side surface portion 30a. When viewed from the direction facing the first end face 10 (that is, in FIG. 2), the recess C is recessed in a substantially arc shape from the virtual contour R on the side of the cutting insert 1 in the short direction (vertical direction in FIG. 2). It has a shape. And the recessed part C is extended from the 1st end surface 10 to the 2nd end surface 20 in the 1st side surface part 30a in the thickness direction (FIG. 4 up-down direction) of the cutting insert. A plurality of recesses C are provided at intervals in the circumferential direction around the central axis O in the first side surface 30a. By forming the recess C in this manner, the corrugated cutting edge 12a has an uneven shape when viewed from the direction facing the first end face 10 (that is, in FIG. 2). In the corrugated cutting edge 12a, only the convex portion of the concavo-convex shape is involved in the cutting, and the chips are generated by being divided in the concave portion.

  As shown in FIG. 2, the corner cutting edge 12 b is configured by combining two arcs 12 b 1 and 12 b 2 having different curvature radii. In the present embodiment, the radius of curvature of the arc 12b1 (first arc) continuing to the corrugated cutting edge 12a is smaller than the radius of curvature of the arc 12b2 (second arc) continuing to the arc 12b1. An inner cutting edge 12c is connected to one end of the arc 12b2 (the end opposite to the end to which the arc 12b1 is connected). The inner cutting edge 12c is provided so as to connect the adjacent corrugated cutting edge 12a and the adjacent corner cutting edge 12c to each other.

  In addition, in the cutting insert 1 of this embodiment, the cutting edge 12 (the corrugated cutting edge 12a, the corner cutting edge 12b, the inner cutting edge 12c) is not limited to the shape shown in the figure, and can be changed to another shape. Is possible. Below, the inclination angle of the rake face corresponding to the cutting edge 12 and the inclination angle of the flank corresponding to the cutting edge 12 will be described with reference to FIGS. 6 shows a sectional view taken along line VI-VI in FIG. 7 shows a sectional view taken along line VII-VII in FIG. FIG. 8 is a cross-sectional view taken along the line VIII-VIII in FIG. FIG. 9 is a cross-sectional view taken along the line IX-IX in FIG. FIG. 10 is a sectional view taken along line XX in FIG. FIG. 11 is a cross-sectional view taken along the line XI-XI in FIG.

  A part of the first end face 10 functions as a rake face 10a (FIG. 2 etc.) with respect to the corresponding cutting edge (corrugated cutting edge 12a, corner cutting edge 12b, inner cutting edge 12c). The rake face 10a is a portion adjacent to each of the cutting edges (the corrugated cutting edge 12a, the corner cutting edge 12b, and the inner cutting edge 12c) of the first end face 10, and the second end face 20 side as the distance from the cutting edge 12 increases. The inclined surface gradually approaches. The rake face 10a corresponding to the corrugated cutting edge 12a is given a positive inclination angle θw (FIG. 6). The inclination angle θw shown in FIG. 6 is perpendicular to the central axis O and passes through the tip of the corrugated cutting edge 12a when the cutting insert 1 is viewed in a cross-section cut in the thickness direction (ie, FIG. 6). It means the intersection angle between the determined virtual plane P3 and the rake face 10a. In FIG. 6, the inclination angle (rake angle) of the rake face 10a when the rake face 10a is positioned below the virtual plane P3 is positive.

  In the present embodiment, the inclination angles θf (FIG. 10) and θe (FIG. 9) of the rake face 10a corresponding to the corner cutting edge 12b (the arc 12b1 and the arc 12b2) and the inclination of the rake face 10a corresponding to the corrugated cutting edge 12a. The angle θw (FIG. 6) is different. That is, the inclination angle θw, the inclination angle θe, and the inclination angle θf are set to different angles, and the inclination angle θw is larger than any of the inclination angle θe and the inclination angle θf.

  Further, the inclination angle of the rake face 10a corresponding to the corner cutting edge 12b is positive, while the inclination angle of the rake face 10a corresponding to the inner cutting edge 12c is negative. That is, the inclination angles θd (FIG. 8), θe (FIG. 9), θf (FIG. 10), and θg (FIG. 11) of the rake face 10a corresponding to the corner cutting edge 12b are all positive inclination angles. On the other hand, the inclination angle θc (FIG. 7) of the rake face 10a corresponding to the inner cutting edge 12c is a negative inclination angle. Note that the inclination angles θd, θe, θf, θg of the rake face 10a corresponding to the corner cutting edge 12b are perpendicular to the central axis O when the cutting insert 1 is viewed in a section cut in the thickness direction, and It means the intersection angle between the imaginary plane P1 (first imaginary plane) defined so as to pass through the tip of the corner cutting edge 12b and the rake face 10a. In addition, the inclination angle θc of the rake face 10a corresponding to the inner cutting edge 12c is perpendicular to the central axis O when the cutting insert 1 is viewed in a cross section cut in the thickness direction and the tip of the inner cutting edge 12c. It means a crossing angle between a virtual plane P2 (second virtual plane) determined to pass through and the rake face 10a. 8 to 11, the inclination angle (rake angle) when the rake face 10a is located below the virtual plane P1 is positive, and in FIG. 7, the rake face 10a is located above the virtual plane P2. The inclination angle (rake angle) is negative.

  Further, the inclination angle of the rake face 10a corresponding to the corner cutting edge 12b decreases from the connecting portion with the corrugated cutting edge 12a toward the connecting portion with the inner cutting edge 12c. Specifically, it corresponds to the inclination angle θd (FIG. 8) of the rake face 10a corresponding to the connecting portion (G2 shown in FIG. 2) between the corner cutting edge 12b and the inner cutting edge 12c, and the arc 12b2 of the corner cutting edge 12b. The inclination angle θe (FIG. 9) of the rake face 10a, the inclination angle θf (FIG. 10) of the rake face 10a corresponding to the arc 12b1 of the corner cutting edge 12b, and the connecting portion between the corner cutting edge 12b and the corrugated cutting edge 12a. When the inclination angle θg (FIG. 11) of the rake face 10a corresponding to (G1 shown in FIG. 2) is compared, there is a relationship of θg> θf> θe> θd. That is, the inclination angle of the rake face 10a decreases as it goes from G1 to G2 shown in FIG.

  As shown in FIG. 12, the inner cutting edge 12c is configured by connecting two linear cutting edges 12c1 and 12c2. That is, the inner cutting edge 12c is not configured in an arc shape like the corner cutting edge 12b when viewed from the direction facing the first end face 10, but is a linear cutting having different extending directions. The blade is combined.

  A part of the peripheral side surface 30 functions as a flank for the corresponding cutting edges (the corrugated cutting edge 12a, the corner cutting edge 12b, and the inner cutting edge 12c). Specifically, the first side face 30a (FIG. 4 and the like) adjacent to the corrugated cutting edge 12a functions as a flank, and the second side face 30b (FIG. 5 and the like) adjacent to the corner cutting edge 12b serves as a flank. The third side surface portion 30c that functions and is adjacent to the inner cutting edge 12c functions as a flank.

  As shown in FIG. 4, the first side surface portion 30 a that functions as a flank adjacent to the corrugated cutting edge 12 a is configured by connecting a corrugated portion 30 a 1, a contact surface 30 a 2, and a connection surface 30 a 3. The corrugated portion 30a1 has a corrugated surface extending so as to have a corrugated shape such as a W shape, an M shape, or a zigzag shape, corresponding to the corrugated cutting edge 12a. The contact surface 30a2 functions as a contact surface with the wall surface of the insert mounting seat of the tool body, and the connection surface 30a3 is connected to the bottom surface side (second end surface 20 side) of the contact surface 30a2. In the present embodiment, the area of the contact surface 30a2 increases from the connecting portion between the corner cutting edge 12b and the corrugated cutting edge 12a toward the connecting portion between the corrugated cutting edge 12a and the inner cutting edge 12c (in other words, cutting) It becomes smaller in the longitudinal direction of the insert 1 in the direction in which the wavy cutting edge 12a approaches the second end face 20 (that is, in the right direction shown in FIG. 4).

  The first side surface portion 30a (the corrugated portion 30a1, the contact surface 30a2, and the connection surface 30a3) functioning as a flank corresponding to the corrugated cutting edge 12a is a cross-section obtained by cutting the cutting insert 1 in the thickness direction through the central axis O. When viewed (that is, in FIG. 6), the relief angle θr3 of the wavy portion 30a1 is negative, the relief angle of the contact surface 30a2 is 0 °, and the relief angle of the connection surface 30a3 is positive. Here, the clearance angle θr3 shown in FIG. 6 means an intersection angle between the undulating portion 30a1 and the virtual plane Q2 that is defined so as to be parallel to the central axis O and along the corrugated cutting edge 12a. The clearance angle when the wavy portion 30a1 is positioned on the opposite side of the central axis O with respect to the virtual plane Q2 (in FIG. 6, on the left side of the virtual plane Q2) is negative. The positive and negative relationship of the clearance angle in the right first side surface portion 30a shown in FIG. 6 is the same as the positive and negative relationship of the clearance angle in the left first side surface portion 30a shown in FIG. is there.

  As shown in FIG. 4, the second side surface portion 30 b that functions as a flank adjacent to the corner cutting edge 12 b progresses in the direction from the first end surface 10 toward the second end surface 20 (downward in FIG. 4). It is inclined so as to approach the central axis O. The third side surface portion 30c (FIGS. 1 and 3, etc.) that functions as a clearance surface adjacent to the inner cutting edge 12c also approaches the central axis O as it proceeds in the direction from the first end surface 10 toward the second end surface 20. It is inclined to. The shapes and sizes of the first side surface portion 30a, the second side surface portion 30b, and the third side surface portion 30c are not limited to the illustrated example. For example, as shown in FIG. 1, the third side surface portion 30 c is configured by connecting a plurality of inclined surfaces 30 c 1, 30 c 2, and 30 c 3, but the shape and number of each surface are not limited to the illustrated example and can be changed as appropriate. It is.

  The clearance angle θr1 (FIG. 10) of the flank corresponding to the arc 12b1 of the corner cutting edge 12b is smaller than the clearance angle θr2 (FIG. 9) of the flank corresponding to the arc 12b2 of the corner cutting edge 12b. The clearance angle θr1 and the clearance angle θr2 are parallel to the central axis O and are defined so as to be along the corner cutting edge 12b, and a clearance surface (second side surface portion 30b) corresponding to the corner cutting edge 12b. Is the crossing angle of each surface when viewed in the cross section shown in FIG. 9 or 10 (that is, the cross section obtained by cutting the cutting insert 1 in the thickness direction).

  As shown in FIG. 13, the third side surface portion 30c functioning as the flank corresponding to the inner cutting edge 12c has a cutting insert 1 as compared to the second side surface portion 30b functioning as the flank corresponding to the corner cutting edge 12b. Projecting in a direction away from the central axis O (leftward in FIG. 2).

  The second end surface 20 (the bottom surface of the cutting insert) is viewed from four sides (two long sides 20a and two short sides 20b) when viewed from the direction facing the second end surface 20 (that is, in FIG. 3). It has a substantially rectangular shape. Each long side part 20a is mutually opposing, and the two short side parts 20b are also arrange | positioned so that it may mutually oppose. As shown in FIG. 3, the second end surface 20 covers the periphery of the attachment hole 5 and extends from the periphery of the attachment hole 5 to the pair of long side portions 20 a and the pair of short side portions 20 b, The two end surfaces 20 have a plurality of inclined surfaces 24a, 24b, 24c, and 24d located in a portion excluding the plane portion 22. Hereinafter, the inclined surfaces 24a, 24b, 24c, and 24d are collectively referred to as the inclined surface 24. In this specification, an example in which there are four inclined surfaces will be described, but a configuration including four or more inclined surfaces may be used, and the number of inclined surfaces can be changed as appropriate.

  As shown in FIG. 3, the flat portion 22 includes a first flat portion 22 a extending in the longitudinal direction of the cutting insert 1 and a second flat portion 22 b extending in the short direction of the cutting insert 1. The first flat surface portion 22a extends on the center side of the short side portion 20b of the second end face 20 from one short side portion 20b to the other short side portion 20b except for the region of the attachment hole 5. The second flat surface portion 22b extends from the one long side portion 20a to the other long side portion 20a on the center side of the long side portion 20a of the second end surface 20 except for the region of the attachment hole 5. The 1st plane part 22a and the 2nd plane part 22b are substantially orthogonal. In addition, the plane part 22 in this embodiment should just extend from the circumference | surroundings of the attachment hole 5 to a pair of long side part 20a and a pair of short side part 20b from the circumference | surroundings of the attachment hole 5, and is an example of illustration. Without being limited thereto, the shape and size of the planar portion 22 can be changed as appropriate.

  As shown in FIG. 3, the inclined surfaces 24 a, 24 b, 24 c, and 24 d are located in a portion of the second end surface 20 excluding the plane portion 22 (in other words, near the four corners of the second end surface 20). The inclined surfaces 24a and 24b are located near the two corners on one end side in the longitudinal direction of the cutting insert 1, and the inclined surfaces 24c and 24d are located near the two corners on the other end side in the longitudinal direction. In the present embodiment, the inclined surfaces 24 a, 24 b, 24 c and 24 d are inclined along the diagonal direction of the second end surface 20. Specifically, the inclined surfaces 24 a, 24 b, 24 c, and 24 d are arranged so that the second end surface becomes closer to the direction away from the center axis O when viewed in a cross section along the diagonal line of the second end surface 20 through the center axis O. It inclines in the direction approaching the 1st end surface 10 from 20. In other words, when the inclined surfaces 24a, 24b, 24c, 24d are assumed to be virtual planes that pass through the center of the second end surface 20 and are perpendicular to the central axis O, the inclined surfaces 24a, 24b, 24c, 24d It is inclined to stand up from the virtual plane. Since the cutting insert 1 has the inclined surface 24 which inclines in this way, when the cutting insert 1 is seen from the side surface (namely, the 2nd side surface part 30b and the 3rd side surface part 30c) of the short side part 11b side among the surrounding side surfaces 30. 2 (that is, in FIG. 5), the short side portion 20b side of the second end face 20 is substantially V-shaped. In other words, when viewed from the short side direction of the cutting insert, the second end surface 20 has a shape protruding outward in a substantially V shape.

  The relationship between the inclination angles of the inclined surfaces 24a, 24b, 24c, and 24d of the second end surface 20 will be described. Specifically, among the inclined surfaces 24a, 24b, 24c, and 24d, the inclined surfaces 24a and 24b located on one end side in the longitudinal direction of the cutting insert 1 (in other words, one end side of the pair of long side portions 20a) Each tilts at a different angle. That is, the inclination angle of the inclined surface 24a is different from the inclination angle of the inclined surface 24b, and the inclination angle of the inclined surface 24c is different from the inclination angle of the inclined surface 24d. Of the inclined surfaces 24a, 24b, 24c, and 24d, the two inclined surfaces located on the diagonal side of the second end surface 20 are inclined at substantially the same angle. That is, the inclination angle of the inclined surface 24a and the inclination angle of the inclined surface 24c are substantially the same angle, and the inclination angle of the inclined surface 24b and the inclination angle of the inclined surface 24d are substantially the same angle. is there.

  The cutting insert 1 may be warped in the direction from the second end surface 20 toward the first end surface 10 (upward in FIG. 4) on the short side 20b side of the second end surface.

  The cutting insert 1 described above is a hard material such as cemented carbide, cermet, ceramic, or ultra-high pressure sintered body containing single crystal diamond, diamond or cubic boron nitride, or PVD or CVD coating film applied thereto. Can be made from things.

  Next, the rotary cutting tool 100 to which the cutting insert 1 of the above embodiment is detachably mounted will be described with reference to FIGS. 14 to 17. FIG. 14 is a perspective view showing a schematic configuration of the rotary cutting tool. FIG. 15 is a side view of the rotary cutting tool shown in FIG. FIG. 16 is a perspective view showing a schematic configuration of the tool body when the cutting insert is removed. FIG. 17 is a side view of the tool body shown in FIG. 16 as viewed from the front end side.

  The rotary cutting tool 100 includes a tool body 110. In the tool body 110, a rotation axis RA extending from the front end side to the rear end side is defined. Here, the tip side refers to the end of the tool body 110 on which the cutting insert 1 is mounted, and is denoted by reference numeral 110a in FIGS. The rear end side refers to an end located on the opposite side. The rotary cutting tool 100 is configured to be rotatable around the rotational axis RA and forward in the rotational direction K (FIG. 15 and the like).

  The tool body 110 has a substantially cylindrical overall shape extending along the rotation axis RA. A plurality of insert mounting seats 120 (FIG. 16 and the like) are formed on the distal end side 110 a of the tool body 110. In the present embodiment, three insert mounting seats 120 are formed, but the number of insert mounting seats 120 may be one or three or more. Each insert mounting seat 120 is formed so as to open forward in the rotational direction K around the rotation axis RA and open to the front end side and the outer peripheral side.

  The insert mounting seat 120 includes a bottom wall surface 120 a that can contact the inclined surface 24 of the second end surface 20 of the cutting insert 1. The bottom wall surface 120a includes two divided surface portions, and each is configured to contact the inclined surface 24 of the cutting insert 1. Therefore, the angle formed by the extended surfaces obtained by extending the two split surface portions of the bottom wall surface 120a is substantially equal to the angle formed by the extended surfaces obtained by extending the inclined surface 24 of the cutting insert 1. Further, a relief portion (that is, an arc-shaped concave portion) is provided between the two bottom wall surfaces 120a. Further, the bottom wall surface 120 a basically has the same shape as the inclined surface 24 of the cutting insert 1 or a corresponding shape, and has a size corresponding to the inclined surface 24. The bottom wall surface 120a faces forward in the rotation direction K. A screw hole 125 for inserting a fixing screw 115 for fixing the cutting insert 1 is formed at substantially the center of the bottom wall surface 120a.

  Furthermore, a chip pocket 117 for discharging chips generated by cutting is provided on the front side of each insert mounting seat 120 in the tool rotation direction K.

  The cutting insert 1 is attached to the insert mounting seat 120 by the fixing screw 115 being screwed into the screw hole 125 through the mounting hole 5.

  According to the cutting insert 1 of the present embodiment described above, the first end surface 10 is composed of a pair of long side portions 11a and a pair of short side portions 11b when viewed from the direction facing the first end surface 10. The cutting edge 12 has a corrugated cutting edge 12a positioned on the pair of long sides 11a and a corner cutting edge 12b connected to one end of the corrugated cutting edge 12a. When viewed from the direction facing the end surface 10 (that is, in FIG. 2), a plurality of concave portions C that are recessed toward the short side of the cutting insert 1 are formed at intervals in the circumferential direction on the first side surface portion 30a. Accordingly, the corrugated cutting edge 12a has an uneven shape, and the inclination angle of the rake face 10a corresponding to the corner cutting edge 12b is smaller than the inclination angle of the rake face 10a corresponding to the corrugated cutting edge 12a. Thus, since the inclination angle of the rake face 10a corresponding to the corner cutting edge 12b is set, the strength of the corner cutting edge 12b can be increased. As a result, chipping of the cutting edge can be suppressed, and the life of the cutting edge can be extended.

  Moreover, according to the cutting insert 1 provided with the structure demonstrated above, the inclined surface 24 of the 2nd end surface 20 is fixed in the state contact | abutted to the bottom wall surface 120a of the insert mounting seat 120. FIG. Since the cutting insert 1 is attached to the tool body 110 in this way, it is seen in a cross section in a direction along a diagonal line of the second end face 20 including the central axis O, specifically, at least four inclined faces inclined in a predetermined direction. Sometimes, the cutting insert 1 is supported by an inclined surface 24) that inclines in a direction approaching the first end surface 10 from the second end surface 20 as it goes away from the central axis O. As a result, the cutting insert 1 can be more firmly fixed to the tool body. Moreover, since the cutting insert 1 of this embodiment has the plane part 22 which covers the circumference | surroundings of the attachment hole 5 at least, damage around the attachment hole 5 can be suppressed. Further, the flat portion 22 extends from the periphery of the mounting hole 5 to the pair of short side portions 10b in the longitudinal direction of the cutting insert 1 and from the periphery of the mounting hole 5 to the pair of long side portions 10a. Since it has the 2nd plane part 22b extended in the transversal direction of the cutting insert 1, the rigidity of the whole bottom face of the cutting insert 1 is securable.

  The embodiments described above are for facilitating the understanding of the present invention, and are not intended to limit the present invention. Each element included in the embodiment and its arrangement, material, condition, shape, size, and the like are not limited to those illustrated, and can be changed as appropriate. In addition, the structures shown in different embodiments can be partially replaced or combined.

DESCRIPTION OF SYMBOLS 1 ... Cutting insert 5 ... Mounting hole 10 ... 1st end surface 10a ... Rake face 12a ... Corrugated cutting edge 12b ... Corner cutting edge 12c ... Inner cutting edge 20 ... 2nd end surface 20a ... Long side part 20b ... Short side part 22 ... Plane Part 22a ... 1st plane part 22b ... 2nd plane part 24a, 24b, 24c, 24d ... Inclined surface 30 ... Peripheral side surface 30a ... 1st side surface part 30b ... 2nd side surface part 30c ... 3rd side surface part 100 ... Rotary cutting tool DESCRIPTION OF SYMBOLS 110 ... Tool body 120 ... Insert mounting seat 120a ... Bottom wall surface P1 ... 1st virtual plane P2 ... 2nd virtual plane

Claims (10)

A first end face; a second end face facing the first end face; and a peripheral side face connecting the first end face and the second end face; and a cross ridge line portion between the first end face and the peripheral side face. A cutting insert having a cutting edge,
When viewed from a direction facing the first end surface, the first end surface has a substantially rectangular shape including a pair of long side portions and a pair of short side portions,
The cutting edge is provided on the pair of long side portions, and has a corrugated cutting edge that exhibits an uneven shape when viewed from a direction facing the first end face, and a corner cutting edge connected to the corrugated cutting edge; Have
The inclination angle of the rake face corresponding to the corner cutting edge is smaller than the inclination angle of the rake face corresponding to the corrugated cutting edge,
Cutting insert. A mounting hole is formed so as to penetrate the first end surface and the second end surface,
The cutting edge further comprises an inner cutting edge located between the corrugated cutting edge and the corner cutting edge,
Assuming a first imaginary plane that passes through the corner cutting edge and is perpendicular to the axis of the mounting hole, the rake face corresponding to the corner cutting edge is as viewed in a cross section in the thickness direction of the cutting insert. Located below the first virtual plane,
Assuming a second imaginary plane that passes through the inner cutting edge and is perpendicular to the axis, the rake face corresponding to the inner cutting edge is the second rim when viewed in a cross section in the thickness direction of the cutting insert. Located above the virtual plane,
The cutting insert according to claim 1. The inner cutting edge is configured by combining linear cutting edges,
The cutting insert according to claim 2. The flank corresponding to the inner cutting edge protrudes in the longitudinal direction of the cutting insert and away from the axis with respect to the flank corresponding to the corner cutting edge.
The cutting insert according to claim 2 or 3. The angle of inclination of the rake face corresponding to the corner cutting edge is determined from the connecting portion between one end of the corner cutting edge and one end of the corrugated cutting edge and the other end on the opposite side of the one end of the corner cutting edge and the inner cutting edge. Decreases as it goes to the connection part with one end of the blade,
The cutting insert according to any one of claims 2 to 4. The corner cutting edge is configured by combining a first arc and a second arc having different radii of curvature,
A radius of curvature of the first arc connected to one end of the corrugated cutting edge is smaller than a radius of curvature of the second arc continuing to the first arc;
The cutting insert according to any one of claims 1 to 5. An inclination angle of the flank corresponding to the first arc is smaller than an inclination angle of the flank corresponding to the second arc;
The cutting insert according to claim 6. When viewed in a cross section in the thickness direction of the cutting insert, the flank corresponding to the corrugated cutting edge is configured by connecting three surfaces having different inclination angles,
The cutting insert according to any one of claims 1 to 7. The flank corresponding to the corrugated cutting edge is provided with a plurality of contact surfaces that contact the wall surface of the insert mounting seat of the tool body to which the cutting insert is attached,
The area of the contact surface decreases from the connecting portion between the corrugated cutting edge and the corner cutting edge toward the connecting portion between the corrugating cutting edge and the inner cutting edge adjacent to the corrugated cutting edge.
The cutting insert according to any one of claims 1 to 8. A first end face; a second end face facing the first end face; and a peripheral side face connecting the first end face and the second end face; and a cross ridge line portion between the first end face and the peripheral side face. A cutting insert having a cutting edge,
When viewed from a direction facing the first end surface, the first end surface has a substantially rectangular shape including a pair of long side portions and a pair of short side portions,
The cutting edge is provided so as to extend along the pair of long sides, and has a corrugated cutting edge that exhibits an uneven shape when viewed from a direction facing the first end surface, and the pair of short sides A corner cutting edge connected to the corrugated cutting edge, and
The inclination angle of the rake face corresponding to the corner cutting edge is smaller than the inclination angle of the rake face corresponding to the corrugated cutting edge,
Cutting insert.

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