Cutting inserts and turning tools

Abstract

A cutting blade that is easy for an operator or a robot to hold is provided. The first and second end faces (10, 20) are formed into a roughly polygonal shape, including: a second and fourth corners (B, H) formed as obtuse angles, and a first and third corners (A, G) formed as acute angles. The peripheral side surface (30) includes: a first curved portion (41) connecting the first and third corners (A, G), a second curved portion (42) connecting the second and fourth corners (B, H), and a first side surface (31) sandwiched between the first and second curved portions (41, 42). The first side surface (31) is inclined relative to the central axis (O). A holding portion (50) is provided on the second curved portion (42), and the holding portion (50) includes at least one of the following two shapes: a plane (51, 53) chamfered parallel to the central axis (O); and a recessed portion (52) formed at a distance from the first and second end faces (10, 20) and recessed toward the central axis (O).

Description

Technical Field

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

[0002] A cutting insert having a cutting edge formed not only on the upper surface but also on the lower surface, and can be flipped upside down and reused, wherein the peripheral side surface connecting the upper surface and the lower surface is usually in the shape of a ridge parallel to the central axis of the upper and lower surfaces. In a cutting insert having such a shape, since the peripheral side surface cannot be tilted relative to the central axis to ensure the back angle, the central axis has to be tilted relative to the tool body to ensure the back angle. Since the orientation of the central axis is restricted, it is necessary to adjust the front angle by raising the peripheral portions of the upper and lower surfaces. In order to coordinate with the raised peripheral portion, the shape of the portion other than the peripheral portion is also restricted. In order to avoid such restrictions, a cutting insert is proposed, in which the peripheral side surface is formed into a spiral shape and tilted relative to the central axis (for example, refer to patent document 1).

[0003] Prior art literature

[0004] Patent Literature

[0005] Patent Document 1: Japanese Patent No. 6424975 Summary of the Invention

[0006] Technical problems to be solved

[0007] However, because the front-to-back and left-to-right sides of the cutting insert having the shape described in FIG. 15 to FIG. 22C of Patent Document 1 are not parallel, it is difficult for a robot or the like to grasp the cutting insert. This presents a new problem of difficulty in mechanical automation. Therefore, an object of the present invention is to provide a cutting insert that is easy for an operator or a robot to grasp.

[0008] Technical solutions to solve problems

[0009] One aspect of the present invention provides a cutting insert comprising: a first end face, a second end face located on the opposite side of the first end face, and a peripheral side face connecting the first end face and the second end face. The first end face is formed into a roughly polygonal shape, comprising: a second corner formed into a second angle, the second angle being an obtuse angle; and a first corner formed into a first angle, the first corner being a corner adjacent to the second corner, the first angle being smaller than the second angle. The second end face is formed into a roughly polygonal shape, comprising: a fourth corner formed into a fourth angle, the fourth angle being an obtuse angle; and a third corner formed into a third angle, the third corner being a corner adjacent to the fourth corner, the third angle being smaller than the fourth angle. The peripheral side face comprises: a first curved portion connecting the first corner and the third corner, a second curved portion connecting the second corner and the fourth corner, and a first side face sandwiched between the first curved portion and the second curved portion. The first side face is inclined relative to a central axis passing through the center of the first end face and the center of the second end face. The second curved portion is provided with a holding portion, which includes at least one of the following two shapes: a plane chamfered parallel to the central axis; and a recessed portion spaced apart from the first end face and the second end face and recessed toward the central axis.

[0010] According to this aspect, because the first side surface is inclined relative to the central axis, the clearance angle of the cutting edge can be adjusted not only by the inclination angle of the cutting insert's central axis relative to the tool body, but also by the inclination angle of the first side surface. This allows for flexible design of the shapes of the first and second end surfaces. Despite the inclination of the first side surface, the grip formed by the grip facilitates handling of the cutting insert by an operator or a robot, making it suitable for automated machining.

[0011] In the above aspect, the first end face and the second end face may be formed into substantially the same rhombus shape, and a grip portion may be provided on a curved portion connecting a corner opposite the second corner and a corner opposite the fourth corner.

[0012] According to this aspect, on the roughly diamond-shaped cutting insert, a pair of obtuse corners can be respectively formed with a gripping portion, and a pair of acute corners can be respectively formed with a cutting edge. Since the cutting insert can be gripped by clamping the pair of obtuse corners, it is convenient to use a robot or the like to grip the cutting insert.

[0013] In the above aspect, the peripheral side surface may further include: a third side surface opposite to the first side surface; a second side surface and a fourth side surface connecting the first side surface and the third side surface, wherein the first side surface and the third side surface are respectively inclined in a manner gradually away from the center axis from the first end surface to the second end surface, and on the other hand, the second side surface and the fourth side surface are respectively inclined in a manner gradually approaching the center axis from the first end surface to the second end surface.

[0014] According to this aspect, the following structure can be formed, in which when the cutting edge formed on the first end face is used, the first and third side faces form a negative clearance angle, and when the cutting edge formed on the second end face is used, the second and fourth side faces form a negative clearance angle. Or the following structure can be formed, in which when the cutting edge formed on the first end face is used, the second and fourth side faces form a positive clearance angle, and when the cutting edge formed on the second end face is used, the first and third side faces form a positive clearance angle. In a cutting insert in which the first and second end faces can be flipped upside down for reuse, the angle of the clearance face can be freely designed. Although the two opposing side faces are not parallel, the holding portion is formed, making it convenient for an operator or a robot to hold the cutting insert.

[0015] In the above aspect, the first angle is an acute angle, and the first end face includes: three corners including a first corner, and the three corners are respectively formed as the first angle; and three corners including a second corner, and the three corners are respectively formed as the second angle. Moreover, the first end face is formed into a roughly hexagon, in which the corners formed into the first angle and the corners formed into the second angle are arranged alternately one after another, and the second end face can be formed into the same shape as the first end face.

[0016] According to this aspect, a generally hexagonal cutting insert having alternating acute and obtuse corners can be gripped by clamping the obtuse corner and the acute corner opposite the obtuse corner. The presence of a gripping portion, such as a flat portion, at the obtuse corner allows for more stable gripping than with a clamping edge. Therefore, even if the peripheral side surface, including the first side surface, is inclined, it is easier for an operator or a robot to grip the cutting insert.

[0017] Another aspect of the present invention provides a blade-replaceable turning tool comprising: a replaceable cutting insert; and a tool body to which the cutting insert is secured. The cutting insert is provided with a grip portion having a recessed shape. The tool body is configured to have a spray hole for spraying coolant toward a cutting edge formed at a first corner, with at least a portion of the coolant reaching the cutting edge from the spray hole passing through the recessed portion.

[0018] According to this aspect, the presence of the grip facilitates gripping of the cutting insert by an operator or a robot. Furthermore, since the coolant is injected through the recessed portion forming the grip, the proportion of coolant that collides with the sides of the cutting insert and diffuses can be reduced, thereby increasing the amount of coolant reaching the cutting edge. By providing a space the size of the recessed portion in the direction of travel of the nozzle for injecting the coolant, the injection hole can be positioned closer to the cutting edge compared to a cutting insert without a recessed portion. The closer the injection hole is positioned, the greater the amount of coolant reaching the cutting edge, allowing for more efficient chip removal.

[0019] Effects of the Invention

[0020] According to the present invention, a cutting insert that is easy for an operator or a robot to hold can be provided. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 is a perspective view showing an example of a turning tool including a cutting insert according to a first embodiment of the present invention;

[0022] Figure 2 is a perspective view showing an example of a cutting insert according to a first embodiment of the present invention;

[0023] Figure 3 For observation from the first end face Figure 2 A top view of the cutting insert is shown;

[0024] Figure 4 For observation from the second end face Figure 2 A bottom view of the cutting insert is shown;

[0025] Figure 5 For observation from the first side Figure 2 A side view of the cutting insert is shown;

[0026] Figure 6 To observe from the second side Figure 2 A side view of the cutting insert is shown;

[0027] Figure 7 is a perspective view showing an example of a cutting insert according to a second embodiment of the present invention;

[0028] Figure 8 For observation from the first end face Figure 7 A top view of the cutting insert is shown;

[0029] Figure 9 is a perspective view showing an example of a cutting insert according to a third embodiment of the present invention;

[0030] Figure 10 is a perspective view showing an example of a cutting insert according to a fourth embodiment of the present invention;

[0031] Figure 11 It is a perspective view showing an example of a cutting insert according to a fifth embodiment of the present invention. DETAILED DESCRIPTION

[0032] The preferred embodiments of the present invention are described with reference to the accompanying drawings. It should be noted that in the various figures, the elements marked with the same reference numerals have the same or similar structures. A feature of the cutting insert 2 of various embodiments of the present invention is that the obtuse corners B, D, F, ... formed on the first end face 10, the obtuse corners H, I, J, L, ... formed on the second end face 20, and the curved portions 42, 44, 46, 48, ... connecting the upper and lower obtuse corners are provided with a gripping portion 50 on the circumferential side 30 (see Figure 3 The gripping portion 50 includes at least one of the following two shapes: a chamfered flat surface 51 parallel to the central axis O of the first and second end faces 10, 20 (see Figure 7 ); or, formed in the middle portion of the first and second end surfaces 10, 20 spaced apart from each other and recessed toward the central axis O 52 (reference Figure 9 Each gripping portion 50 may be a combination of a recess 52 and a flat surface 53 (see Figure 10 ), and may also include multiple planes 51, 53 (refer to Figure 2 ).

[0033] Since the side surfaces 31, 32, 33, 34, 35, 36, ... of the cutting insert 2 are inclined relative to the central axis O (see Figure 5 and Figure 6 ), so when clamping such a side, a part of the horizontal force used for clamping will generate a component force in the vertical direction due to the inclined surface. The robot can easily slide along the inclined side. According to this embodiment, it will not be difficult to hold the side surfaces 31, 32, 33, 34, 35, 36... of the cutting blade 2, but it will be convenient to clamp the holding portion 50 provided at the obtuse corner to hold the cutting blade 2. Therefore, it is suitable for mechanical automation. If the holding portion 50 includes a recess 52, the coolant can be sprayed through the recess 52 (refer to Figure 1 ). Below, combined with Figures 1 to 11 Each structure is described in detail.

[0034] Figure 1 1 is a perspective view showing an example of a turning tool 1 having a cutting insert 2 according to a first embodiment of the present invention. Figure 1 As shown, a blade-replaceable turning tool 1 includes a replaceable cutting insert 2 and a tool body 3 to which the cutting insert 2 is fixed. The tool body 3 is fixed to a tool holder or the like for use. An insert mounting seat 7 and a spray hole 6 are provided at the front end portion of the tool body 3. The front end portion includes the front end of the tool body 3 and the portion adjacent thereto. The spray hole 6 sprays coolant toward the cutting insert 2, which is restrained on the insert mounting seat 7.

[0035] Figure 2FIG1 is a perspective view showing an example of a cutting insert 2 according to the first embodiment of the present invention. The material of the cutting insert 2 is not particularly limited, and various materials for cutting inserts, such as cemented carbide, can be used. Figure 2 As shown, the cutting insert 2 includes a first end surface 10 , a second end surface 20 located on the opposite side of the first end surface 10 , and a peripheral side surface 30 connecting the first and second end surfaces 10 , 20 .

[0036] It should be noted that, in order to emphasize the peripheral side surface 30 as a key part of the present invention, Figure 2 In the following figures, the shapes of the first and second end faces 10 and 20 are simplified. Figure 1 As shown, the first and second end surfaces 10 and 20 include: a mounting hole 9 extending through the first and second end surfaces 10 and 20; cutting edges formed on the ridges ABCD and GHIJ; a rake face 11 facing the cutting edge; and a protruding surface 12 protruding from the rake face 11. When the cutting insert 2 is placed on a horizontal surface such as a platform, the cutting insert 2 is supported by the protruding surface 12 abutting against the horizontal surface. In the illustrated example, the protruding surface 12 is formed as a flat surface and surrounds the mounting hole 9. The protruding surface 12 of the first end surface 10 and the protruding surface (not shown) on the second end surface 20 are parallel to each other.

[0037] A cutting edge is formed on at least a portion of the ridgeline ABCD where the first end face 10 and the peripheral side face 30 intersect. Similarly, a cutting edge is also formed on at least a portion of the ridgeline GHIJ where the second end face 20 and the peripheral side face 30 intersect. In the illustrated example, corner cutting edges are formed at the acute corners A and C of the first end face 10 and the acute corners G and I of the second end face 20, and the main cutting edge (side cutting edge) and the secondary cutting edge (front cutting edge) are formed in a manner that clamps each corner cutting edge. The structure of the cutting edge is not limited to the illustrated example. Figure 3 and Figure 4 Describe the cutting edge in detail.

[0038] In the illustrated example, the peripheral side surface 30 includes: first to fourth flat side surfaces 31, 32, 33, and 34; and first to fourth curved portions 41, 42, 43, and 44 connecting the first to fourth side surfaces. The first to fourth side surfaces 31, 32, 33, and 34 are formed at positions on the sides AB, BC, CD, and DA facing the first end surface 10, and the first to fourth curved portions 41, 42, 43, and 44 are formed at positions on the corners A, B, C, and D facing the first end surface 10. In other words, on the peripheral side surface 30, the first side surface 31 is sandwiched between the first and second curved portions 41 and 42, the second side surface 32 is sandwiched between the second and third curved portions 42 and 43, the third side surface 33 is sandwiched between the third and fourth curved portions 43 and 44, and the fourth side surface 34 is sandwiched between the fourth and first curved portions 44 and 41.

[0039] Figure 3 For observation from the first end face 10 Figure 2 A top view of the cutting insert 2 is shown. Figure 4 For observation from the second end face 20 Figure 2 A bottom view of the cutting insert 2 is shown. In the illustrated example, the first and second end faces 10, 20 have substantially the same shape and function. In the turning tool 1, the first end face 10 may be the upper surface side (the front cutting edge side) and the second end face 20 may be the lower surface side (the constraint surface side disposed on the tool body 3). It may also be flipped upside down, with the second end face 20 being the upper surface side and the first end face 10 being the lower surface side. Therefore, this article will provide a detailed description using the first end face 10 as an example, and repeated description of the second end face 20 may be omitted. It should be noted that the first and second end faces 10, 20 do not necessarily have to be the same shape.

[0040] In the example shown in the figure, the first end face 10 is a roughly rhombus-shaped shape with four corners ABCD and is formed symmetrically at 180° around the center O1. Similarly, the second end face 20 is a roughly rhombus-shaped shape with four corners GHIJ and is formed symmetrically at 180° around the center O2. Hereinafter, the straight line connecting the center O1 of the first end face 10 and the center O2 of the second end face 20 is referred to as the central axis O of the first and second end faces 10 and 20. It should be noted that the central axis O can be a straight line that passes through the first end face 10 and the second end face 20. Figure 1 The center axis of the mounting hole 9 of the first and second end surfaces 10 and 20 is shown. If the first and second end surfaces 10 and 20 are not point-symmetrical, the center of gravity of the first and second end surfaces can be centers O1 and O2. The center axis O is perpendicular to the protruding surface of the first and second end surfaces 10 and 20.

[0041] The main cutting edge extends from the acute corner A to the obtuse corner B on side AB, from the acute corner C to the obtuse corner D on side CD, from the acute corner G to the obtuse corner J on side GJ, and from the acute corner I to the obtuse corner H on side IH. The main cutting edge is formed so as to be substantially parallel to the longitudinal direction of the tool body 3 when the cutting insert 2 is fixed to the tool body 3.

[0042] The minor cutting edge extends from the acute corner A to the obtuse corner D on the side AD, extends from the acute corner C to the obtuse corner B on the side CB, extends from the acute corner G to the obtuse corner H on the side GH, and extends from the acute corner I to the obtuse corner J on the side IJ. The minor cutting edge is formed so as to be substantially parallel to the width direction of the tool body 3 when the cutting insert 2 is fixed to the tool body 3.

[0043] In the illustrated example, acute corners A, C, G, and I are formed at 80°, and obtuse corners B, D, H, and J are formed at 100°. Regarding the technical features of the present invention, in the first embodiment and the second to fourth embodiments described below, an example of the second and fourth angles being obtuse angles is 100°, an example of the first and third angles being smaller than the second and fourth angles is 80°, an example of the second corner formed at the second angle is corner B, an example of the first corner formed at the first angle is corner A, the first corner is a corner adjacent to the second corner, an example of the fourth corner formed at the fourth angle is corner H, an example of the third corner formed at the third angle is corner G, and the third corner is a corner adjacent to the fourth corner.

[0044] Figure 5 For observation from the first side 31 Figure 2 The side view of the cutting blade 2 shown. Figure 5 and Figure 3 As shown, the second and fourth side surfaces 32 and 34 facing each other are inclined from the first end surface 10 to the second end surface 20 , that is, the further downward, the farther away from the central axis O. In other words, the further downward, the greater the distance between the second and fourth side surfaces 32 and 34 .

[0045] Figure 6 For observation from the second side 32 Figure 2 The side view of the cutting blade 2 shown. Figure 6 and Figure 4 As shown, the first and third side surfaces 31 and 33 facing each other are inclined from the first end surface 10 to the second end surface 20, that is, the further downward, the closer to the central axis O. In other words, the further downward, the smaller the distance between the first and third side surfaces 31 and 33.

[0046] The following, combined Figure 2 and Figure 3 The grip portion 50 will be described. Figures 2 to 10 One feature of the generally rhombus-shaped cutting insert 2 shown is that the gripping portions are not formed on a pair of acute corners A and C serving as cutting edges, but are formed on a pair of obtuse corners B and D not serving as cutting edges. Figure 3 As shown, a gripping portion 50 is provided on the curved portions 42 and 44 connecting the obtuse corners B and D of the first end face 10 and the obtuse corners H and I of the second end face 20. Figure 2 As shown, each holding portion 50 includes: a flat plane (flat surface) 51, 51 chamfered parallel to the center axis O, a recess 52 clamped from the upper and lower sides on the plane 51, and a flat plane (flat surface) 53 formed parallel to the center axis O at the bottom of the recess 52.

[0047] like Figure 3 As shown, the planes 51 and 53 are formed parallel to the central axis O. That is, they are formed perpendicular to the first and second end faces 10 and 20. In the illustrated example, at each corner B and D, the plane 51 facing the upper side of the first end face 10 is flush with the plane 51 facing the lower side of the second end face 20. In the illustrated example, the plane 51 of the corner B and the plane 51 of the corner D located at the diagonal corners of the first end face 10 are formed parallel to each other, and the plane 53 of the corner B and the plane 53 of the corner D are formed parallel to each other. In the illustrated example, at each corner B and D, the planes 51 and 53 are formed parallel to each other. It should be noted that the structure of the planes 51 and 53 is not limited to the illustrated example. For example, the plane 51 of the corner B and the plane 51 of the corner D located at the diagonal corners may not be parallel, and at the corner B, the plane 51 and the plane 53 may not be parallel.

[0048] like Figure 2 As shown, the plane 51 on the second curved portion 42 is formed in the following manner: when the first end surface 10 is approximately polygonal, the vertex corresponding to the second corner is cut off (chamfered). Figure 9 The vertex of the corner B of the third embodiment shown) and the vertex corresponding to the fourth corner when the second end face 20 is approximately polygonal (for example, Figure 9 A virtual edge line of the vertex of the corner H of the third embodiment shown.

[0049] like Figure 2 As shown, the recess 52 is formed at a distance from the first and second end faces 10, 20 and is recessed inwardly toward the central axis O. In the illustrated example, the recess 52 is formed at the upper and lower centers of the first curved portion 41, that is, in the middle portion of the first curved portion 41 that is equally spaced from the first and second end faces 10, 20 in the axial direction of the central axis O. Figure 1 A portion of the coolant ejected from the cooling medium and sprayed toward the cutting edge of the cutting insert 2 collides with the peripheral side surface 30 of the cutting insert 2 and spreads out, thereby failing to reach the cutting edge. Figure 3 The dot-dash line in FIG. 1 shows a trajectory W of the coolant in a state where the cutting insert 2 is removed from the insert seat 7 .

[0050] like Figure 3 As shown, if the trajectory W of the coolant in the absence of obstacles is projected parallel to the central axis O relative to the cutting insert 2 constrained on the insert mounting seat 7, at least a portion of the trajectory W will overlap with the recess 52. In other words, at least a portion of the coolant reaching the cutting edge will pass through the recess 52. By providing an opening of the same size as the recess 52 in the direction of travel of the nozzle 6 that sprays the coolant W, the proportion of the coolant W that collides with the peripheral side surface 30 of the cutting insert 2 and diffuses can be reduced, thereby increasing the amount of coolant reaching the cutting edge.

[0051] The depth of the recess 52, that is, the distance between the plane 51 and the plane 53 is not limited to the example shown in the figure. For example, the recess 52 can be set to a shallower depth, as long as it is a depth that does not slip and fall off when held by a robot or the like. The recess 52 can also be set to a deeper depth to avoid the trajectory W of the coolant from the injection hole 6 to the cutting edge. Observing the plane 53 on the holding portion 50 that serves as the bottom of the recess 52, it can also be considered that the plane 51 protrudes from the plane 53. The more the plane 51 protrudes from the plane 53, the greater the contact area between the peripheral side surface 30 (the second and third side surfaces 32, 33) and the insert mounting seat 7 of the tool body 3. Therefore, the constraint state of the cutting insert 2 is stable near the first and second end surfaces 10, 20.

[0052] According to the cutting blade 2 of the first embodiment constructed as described above, on the cutting blade whose first end face and second end face are formed into a roughly rhombus shape, the holding portion is not formed at the first corner A with an acute angle, but is formed at the second corner B with an obtuse angle and the obtuse corner D located at its diagonal corner. Therefore, on the roughly rhombus-shaped cutting blade, a pair of obtuse corners can be formed with holding portions, and a pair of acute corners can be formed with cutting edges. The pair of obtuse corners can be held by clamping them. Although the first side surface 31 is inclined, the holding portion 50 is formed thereon, making it easy for an operator or a robot to hold the cutting blade. It is suitable for mechanical automation. In the first embodiment, since each holding portion 50 includes a plurality of shapes that are easy to hold, such as two planes 51, a recess 52, and a plane 53, there is a high degree of freedom in choosing how to hold the blade. It can cope with various robots, etc. Since the position of the injection hole 6 can be designed so that part of the coolant passes through the recess 52 , the injection hole 6 can be positioned closer to the cutting edge compared to the cutting insert 2 of the second embodiment without the recess 52 .

[0053] Next, combine Figures 7 to 11 The cutting inserts 2 according to the second to fifth embodiments will now be described. It should be noted that structures having the same or similar functions as those in the first embodiment are designated with the same reference numerals, and reference can be made to the corresponding descriptions in the first embodiment, and no further description will be given here. In addition, except for the structures described below, the other structures are the same as those in the first embodiment.

[0054] Figure 7 It is a perspective view showing an example of a cutting insert 2 according to a second embodiment of the present invention. Figure 8 For observation from the first end face 10 Figure 7 The top view of the cutting blade 2 shown. Figure 7As shown in FIG, the grip portion 50 is composed only of a flat surface 51 chamfered parallel to the central axis O. In this point, the second embodiment is different from the first embodiment. Figure 8 In the example shown, the flat surfaces 51 formed at the obtuse corners B and D are parallel to each other. According to the second embodiment, similar to the first embodiment, a cutting insert 2 that is easy for an operator or a robot to hold can be provided.

[0055] Figure 9 FIG. 2 is a perspective view showing an example of a cutting insert 2 according to a third embodiment of the present invention. Figure 9 As shown, the third embodiment differs from the first embodiment in that the grip portion 50 consists solely of a recessed portion 52 recessed toward the central axis O. According to the third embodiment, as in the first embodiment, the operator's finger or the tip of a robotic arm can be hooked onto the recessed portion 52, making it easier to grip the cutting insert. The injection hole 6 can be positioned so that a portion of the coolant passes through the recessed portion 52, allowing the injection hole 6 to be positioned closer to the cutting edge.

[0056] Figure 10 1 is a perspective view showing an example of a cutting insert according to a fourth embodiment of the present invention. Figure 10 As shown, the bottom of the recess 52 is formed with a flat surface 53. The fourth embodiment differs from the third embodiment in that the recess 52 is not only recessed toward the central axis O but also has a flat surface 53 formed parallel to the central axis O at the bottom of the recess 52. According to the fourth embodiment, as in the first and third embodiments, an operator's finger or the tip of a robot arm can be hooked onto the recess 52. As in the first embodiment, the flat surface 53 formed at the bottom of the recess 52 can also be gripped.

[0057] Figure 11 1 is a perspective view showing an example of a cutting insert according to a fifth embodiment of the present invention. The fifth embodiment differs from the second embodiment in that the first and second end faces 10 and 20 are not roughly rhombus-shaped. The first end face 10 is formed into a roughly hexagonal shape, wherein the three corners A, C, and E formed as acute angles and the three corners B, D, and F formed as obtuse angles are arranged alternately. The second end face 20 is formed into a roughly hexagonal shape, wherein the three corners G, I, and K formed as acute angles and the three corners H, J, and L formed as obtuse angles are arranged alternately. A gripping portion 50 is formed on each of the curved portions 42, 44, and 46 connecting the obtuse corners.

[0058] In the illustrated example, acute corners A, C, E, G, I, and K are formed at 80°, and obtuse corners B, D, F, H, J, and L are formed at 160°. Regarding the technical features of the present invention, in a fifth embodiment, an example of the second and fourth angles being obtuse angles is 160°, an example of the first and third angles being smaller than the second and fourth angles is 80°, an example of the second corner formed at the second angle is corner B, an example of the first corner formed at the first angle is corner A, the first corner is a corner adjacent to the second corner, an example of the fourth corner formed at the fourth angle is corner H, an example of the third corner formed at the third angle is corner G, and the third corner is a corner adjacent to the fourth corner.

[0059] The first side surface 31 (surface ABHG) sandwiched between the first and second curved portions 41 and 42 is inclined so as to gradually approach the central axis O from the first end surface 10 to the second end surface 20. The second side surface 32 (surface BCIH) sandwiched between the second and third curved portions 42 and 43 is inclined so as to gradually move away from the central axis O from the first end surface 10 to the second end surface 20. Similarly, the third to sixth side surfaces 33, 34, 35, and 36 are inclined relative to the central axis O. In contrast, the plane 51 constituting the gripping portion 50 is formed parallel to the central axis O. It should be noted that the gripping portion 50 is not limited to the example shown in the figure. The gripping portion 50 may also be constituted by a recessed portion 52 that is recessed toward the central axis O.

[0060] According to the fifth embodiment, for example, the cutting insert 2 can be held by clamping the gripping portion 50 provided at the obtuse corner B and the acute corner E located at the diagonal position opposite to the corner B. The gripping portion 50 having a flat surface 51 formed flat on the obtuse corner B enables more stable clamping than clamping the inclined first side surface 31 facing the side AB, thereby facilitating gripping of the cutting insert 2 by an operator or a robot.

[0061] The embodiments described above are intended to facilitate understanding of the present invention and are not intended to limit the present invention. The various elements and their configurations, materials, conditions, shapes, and dimensions included in the embodiments are not limited to examples and may be appropriately modified. In addition, the structures shown in different embodiments may be partially replaced or combined.

[0062] Description of Reference Numerals

[0063] 1 Turning tools

[0064] 2 cutting blades

[0065] 3 Tool body

[0066] 6 injection holes

[0067] 7-blade mounting seat

[0068] 8 Fastening screws

[0069] 9 mounting holes

[0070] 10 first end surface

[0071] 11 Rake face

[0072] 12 protruding surface

[0073] 20 second end surface

[0074] 30-week side view

[0075] 31-36 First to sixth side

[0076] 41-46 First to sixth bends

[0077] 50 handle

[0078] 51, 53 planes

[0079] 52 recess

[0080] Corner of the first end face of A to F

[0081] Corner of the second end face of G~L

[0082] O Center axis

[0083] O1 Center of the first end face

[0084] Center of the second end face of O2

[0085] W Coolant Trajectory

Claims

1. A cutting insert comprising: a first end surface, a second end surface located on the opposite side of the first end surface, and a peripheral side surface connecting the first end surface and the second end surface, The first end face is formed into a substantially polygonal shape, including: a second corner formed at a second angle, the second angle being an obtuse angle; and a first corner formed at a first angle, the first corner being a corner adjacent to the second corner, the first angle being smaller than the second angle. The second end face is formed into a substantially polygonal shape, including: a fourth corner formed at a fourth angle, the fourth angle being an obtuse angle; and a third corner formed at a third angle, the third corner being a corner adjacent to the fourth corner, the third angle being smaller than the fourth angle. The peripheral side surface includes: a first curved portion connecting the first corner and the third corner; a second curved portion connecting the second corner and the fourth corner; and a first side surface sandwiched between the first curved portion and the second curved portion. The first side surface is inclined relative to a central axis passing through the center of the first end surface and the center of the second end surface, The second curved portion is provided with a handle. The holding portion includes a concave shape that is formed at a distance from the first end surface and the second end surface and is recessed toward the central axis.

2. The cutting insert according to claim 1, wherein The first end surface and the second end surface are formed into substantially the same rhombus shape, The gripping portion is also provided on a curved portion connecting a corner located diagonally opposite to the second corner and a corner located diagonally opposite to the fourth corner.

3. The cutting insert according to claim 2, wherein The peripheral side surface further includes: a third side surface opposite to the first side surface, and a second side surface and a fourth side surface connecting the first side surface and the third side surface. The first side surface and the third side surface are inclined so as to gradually move away from the central axis from the first end surface to the second end surface. The second side surface and the fourth side surface are respectively inclined so as to gradually approach the central axis from the first end surface toward the second end surface.

4. The cutting insert according to claim 1, wherein The first angle is an acute angle, The first end surface includes: three corners including the first corner, each formed at the first angle; and three corners including the second corner, each formed at the second angle. Moreover, the first end surface is formed into a substantially hexagonal shape, wherein the corners formed at the first angle and the corners formed at the second angle are alternately arranged one after another. The second end surface is formed in the same shape as the first end surface.

5. A turning tool with replaceable blade, comprising: A replaceable cutting insert and a tool body for fixing the cutting insert, The cutting blade comprises: a first end surface, a second end surface located on the opposite side of the first end surface, and a peripheral side surface connecting the first end surface and the second end surface, The first end face is formed into a substantially polygonal shape, including: a second corner formed at a second angle, the second angle being an obtuse angle; and a first corner formed at a first angle, the first corner being a corner adjacent to the second corner, the first angle being smaller than the second angle. The second end face is formed into a substantially polygonal shape, including: a fourth corner formed at a fourth angle, the fourth angle being an obtuse angle; and a third corner formed at a third angle, the third corner being a corner adjacent to the fourth corner, the third angle being smaller than the fourth angle. The peripheral side surface includes: a first curved portion connecting the first corner and the third corner, a second curved portion connecting the second corner and the fourth corner, and a first side surface sandwiched between the first curved portion and the second curved portion. The first side surface is inclined relative to a central axis passing through the center of the first end surface and the center of the second end surface, The second curved portion is provided with a handle. The holding portion includes a concave shape that is spaced apart from the first end surface and the second end surface and is recessed toward the central axis. The tool body is composed of: A spray hole is provided, wherein the spray hole sprays coolant toward the cutting edge formed at the first corner, At least a portion of the coolant reaching the cutting edge from the injection hole passes through the recess.

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