JP2006082168A - Insert and throw-away type cutting tool - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To completely and promptly discharge chips generated in a high feed processing in the prescribed flow-out direction without causing clogging. <P>SOLUTION: An insert body 1 having a polygonal flat shape forms an attachment hole 5 opening upper and lower faces 2, 3 and penetrating therethrough, and cutting faces 6 having corner blades 7 at the tip of the corner portions on the upper face 2 and cutting blades 8 at one side edge portions 6A continuous to one ends 7A. Projection portions 12 having upper edge faces 12A continuous to the side edge portions are formed on the inner side of the other side edge portions 6B of the cutting faces 6 to position upper face 2 side opening edge portions 5A of the attachment hole 5 rather on the lower face 3 side than the upper edge faces 12A. On the other hand, recess portions 13 which extend toward the lower face 3 side according to that a bottom face 14 goes toward the attachment hole 5 side to reach the opening edge portions 5A and are recesses against the projection portions 12 are formed on the inner side of the cutting faces 6 from the corner blades 7 toward the cutting blades 8. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an insert that is detachably attached to a throw-away cutting tool (hereinafter referred to as a cutting tool), and a cutting tool to which the insert is attached.

As this type of insert (throw away tip) and cutting tool, the inventors of the present invention disclosed in Patent Document 1 that the front and back surfaces forming the polygon of the throw away tip body having a polygonal flat plate shape are selectively scooped. And corner corners of these front and back surfaces are formed with arcuate corner blades, and throwaway tips with main cutting edges formed on the side ridges of the front and back surfaces that are connected to one end of the corner blades, The tip edge of the tool body is directed to the outer periphery of the tip of the tool body rotated about the axis, and one of the front and back surfaces is selectively used as the rake face in the direction of rotation of the tool body. In addition to projecting to the outer peripheral side, the main cutting blade projects to the tip end side of the tool body so as to incline toward the tip end side from one end of the corner blade toward the inner periphery side of the tool body. Proposing a cutting tool that is detachably attached by arranging the side ridges of the front and back surfaces connected to the other end of the corner blade to be inclined toward the inner peripheral side of the tool body toward the rear end side in the axial direction. Yes. And in this patent document 1, in order to improve chip disposal and to perform smooth cutting, a grooved breaker is formed inside the front and back surfaces along the main cutting edge from the corner blade, In addition, it has also been proposed to form a side ridge that is continuous with the other end of the corner blade.
JP 2003-275920 A

  By the way, in recent years, this type of insert and cutting tool is often used for high-feed machining in which the feed amount during machining is set to be relatively large, and recently, there is a tendency to further increase the rotational speed and feed amount of the tool body. In such high-feed processing, the amount of cutting per blade and the outflow speed of chips are increased, so that rapid chip discharge is required. However, the groove-shaped breaker in the throw-away tip described in Patent Document 1 refers to the corner blade and the main cutting edge after guiding the chips generated by the corner blade and the main cutting edge into the breaker. The purpose of the breaker is to forcibly curl and split by colliding with the opposite breaker wall surface, and when such a breaker generates a large amount of chips at a high speed and flows out, clogging occurs in the breaker. Therefore, it may be difficult to sufficiently satisfy the above-described requirements in terms of chip dischargeability. On the other hand, if the rake face is simply a flat face, the flow direction of the chips generated at a high speed at a high speed is not determined, and the result is that the smooth chip treatment is impaired.

  The present invention has been made under such a background. In particular, it causes clogging of chips generated at a high speed and in a large amount in high feed processing with higher rotational speed and feed amount as described above. The object is to provide an insert and a cutting tool that can be discharged quickly and reliably in a predetermined outflow direction.

  In order to solve the above-described problems and achieve such an object, the insert of the present invention has an insert body having a polygonal flat plate shape and an opening on the upper and lower surfaces forming the polygon. A mounting hole penetrating in the vertical direction is formed, a rake face is formed at the corner of the upper surface of the insert body, and a corner blade is formed at the tip of the corner where the rake face is formed. In addition, a cutting edge is formed on one side ridge of the rake face connected to one end of the corner blade, and the other side ridge of the rake face connected to the other end of the corner blade is formed on the rake face. A convex portion having an upper end surface connected to the other side ridge portion is formed inside, and the upper surface side opening edge portion of the mounting hole is located on the lower surface side of the insert body with respect to the upper end surface of the convex portion. While the above corner blades A concave portion that is concave with respect to the convex portion is formed on the inner side of the rake face over the cutting edge, and the bottom surface of the concave portion extends toward the lower surface side toward the mounting hole side. It reaches the upper surface side opening edge of the mounting hole.

  In addition, the cutting tool of the present invention has such an insert as a positive insert on the outer periphery of the tip end of the tool body rotated around the axis, and the upper surface of the insert body is directed in the rotation direction of the tool body. The corner blade at the tip of the rake face formed at the corner of the upper surface protrudes to the outer peripheral side of the tip of the tool body and is detachably attached by a clamp member inserted through the attachment hole. In this mounted state, the cutting blade formed on the one side ridge portion connected to one end of the corner blade is inclined toward the tip side from one end of the corner blade toward the inner peripheral side of the tool body. The other side ridge portion connected to the other end of the corner blade is inclined toward the inner peripheral side of the tool body as it goes toward the rear end side in the axial direction. Furthermore, the bottom surface of the recess formed on the rake face inside the cutting blade extends toward the rear side in the rotational direction as it goes toward the rear end side in the axial direction. It is characterized by.

  In the insert having the above configuration, a convex portion is formed on the rake face on the inner side of the other side ridge portion of the rake face continuous with the other end of the corner blade. A concave portion that is concave with respect to the convex portion is formed inside the cutting edge formed on one side ridge portion of the rake face that is continuous with one end, and thus is generated by the corner blade and the cutting blade. The cutting direction of the chips is regulated by the standing wall surface formed between the convex portion and the concave portion, and flows out to the inside of the upper surface along the bottom surface of the concave portion. And the opening edge part of the upper surface side in which the rake face of the mounting hole formed in the insert body is formed is located on the lower surface side of the insert body from the upper end surface of the convex part, and the bottom surface of the concave part is also this The mounting hole extends toward the lower surface of the insert body as it goes toward the mounting hole, and reaches the opening edge of the upper surface of the mounting hole. In other words, the mounting hole in which the inside of the rake face of the concave portion is lowered from the convex portion Therefore, chips flowing out along the concave portion flow into the space as they are without being interrupted and are quickly discharged from the rake face.

  Therefore, according to the insert configured as described above, the cutting tool to which the insert is attached can be used for high feed processing in which the rotation speed and feed amount of the tool body are set higher as described above, even at high speed. A large amount of generated chips can be discharged quickly without clogging or staying, and the discharge direction of the chips is controlled by regulating the flow direction of chips on the rake face by the standing wall. Therefore, smooth chip disposal can be promoted. Furthermore, in the insert having the above-described configuration, a concave portion having a bottom surface facing the lower surface is formed inside the corner blade and the cutting blade, so that the substantial rake angle of the corner blade and the cutting blade is increased to the positive angle side. Therefore, in the cutting tool having the above-described configuration, the bottom surface of the recess is extended so as to extend toward the rear side in the rotational direction as it goes toward the rear end side in the axial direction of the tool body. An effect that cutting resistance can be reduced also in the feed processing is obtained.

  Further, in the insert, on the corner blade and the cutting blade side of the bottom surface of the concave portion, the section of the insert main body becomes closer to the mounting hole side so that a cross section perpendicular to the corner blade or the cutting blade forms a convex curve. Despite the fact that the rake angle of the corner blade and the cutting blade can be increased to the positive angle side and the sharpness can be improved by forming the convex curved portion toward the lower surface side, the corner blade and the cutting blade can be improved. It is possible to maintain a sufficient thickness around the cutting edge of the blade itself to maintain the cutting edge strength, and the cutting edge may be damaged even in the high feed processing as described above, which places a heavy burden on the cutting edge. Can be prevented. Further, by forming the convex curved surface portion on the corner blade or the cutting edge side of the bottom surface of the concave portion in this way, it is possible to improve the separation of the chip from the bottom surface of the concave portion, and it is also possible to prompt the quicker chip discharge.

  When the convex curved surface portion is formed in this way, the radius of curvature of the convex curve formed by the convex curved surface portion in the cross section orthogonal to the corner blade or the cutting blade is the total length of the corner blade and the cutting blade. Accordingly, when the chips generated with a width extending from the corner blades to the cutting edge connected to one end of the corner blades flow out along the convex curved surface portion, the chips are partially broken in the width direction. It is possible to prevent the flow from changing and hindering the control of the outflow direction.

  However, the chip generated from the corner blade to the cutting blade does not necessarily have a constant generation speed and thickness in the width direction. For example, when the chip is attached to the cutting tool as described above, The corner blade side located on the outer periphery of the tip of the main body has a larger diameter from the rotation axis than the inner peripheral cutting edge, so the peripheral speed is faster and the generation rate of chips increases, resulting in a faster tool body rotation. As a result, more chips are produced. Therefore, in such a case, particularly when the radius of curvature of the convex curved surface portion is made substantially equal from the corner blade to the entire length of the cutting blade as described above, a large amount of chips generated on the corner blade side are clogged. In order to prevent such clogging due to the difference in the generation speed in the width direction of the chips, the convex curve formed by the convex curved surface portion in the cross section perpendicular to the corner blade or the cutting blade may be used. By making the angle formed by the straight line passing through both ends of the curve with respect to the plane perpendicular to the thickness direction different from the other portions in at least a part of the corner blade and the cutting blade, the convex curved surface portion is inserted. Adjust the amount of dents that drop into the lower surface of the main unit, that is, the pocket capacity of the concave parts in the convex curved part, over the direction in which the corner blades and cutting edges extend. And or by increasing the angle, it is desirable to make larger pocket volume in a portion where the chips become clogged slightly is ensured.

  Furthermore, on the upper surface side opening edge side of the mounting hole on the bottom surface of the concave portion opposite to the convex curved surface portion, the convex portion is formed such that a cross section perpendicular to the corner blade or cutting edge forms a concave curve. By forming a concave curved surface portion that further toward the lower surface side of the insert main body from the curved surface portion toward the mounting hole side, chips flowing out from the corner blade and the cutting blade side through the convex curved surface portion are more smoothly discharged. In addition, the pocket capacity of the recess can be further increased. It should be noted that the concave curve formed by the cross section of the concave curved surface portion is smoothly in contact with the convex curve formed by the convex curved surface portion, or if the gap is connected by the tangent of both curves, smoother chips can be formed. Ejection can be promoted, but the concave and convex curves may be bent and connected, and the radius of curvature may be different from the other parts in at least a part of the corner blade and the cutting edge. .

  Further, the cutting blade may be formed in a convex curve shape such as a convex arc when viewed from the direction facing the rake face, but the cutting blade is opposite to one end of the corner blade and the corner blade. Compared to the case where the cutting edge is formed in a convex curve shape as described above by forming one straight line connecting the above end portions on the side or a broken line shape composed of a plurality of straight lines intersecting each other at an obtuse angle. This makes it possible to shorten the overall length of the cutting blade and prevent an increase or fluctuation in cutting resistance. In addition, the cutting edge can be expected to have a cutting effect especially when the cutting blade is formed by a plurality of straight lines. Thus, it becomes possible to promote a more stable chip disposal.

  Further, for example, when the cutting blade is formed in a polygonal line, the main cutting edge connected to one end of the corner blade and the corner blade of the cutting blade connected to the main cutting edge are connected to the cutting blade. By providing a secondary cutting edge that reaches the opposite end and retracts to the inside of the upper surface with respect to the extension line of the primary cutting edge at the intersection with the primary cutting edge, the secondary cutting edge is a tool in the cutting tool. By attaching the insert so as to extend along a plane perpendicular to the axis of the main body, a smoother plane portion can be formed.

  On the other hand, in the cutting tool, the clamp member is a clamp screw having a head used for a general screw-on type clamp, and the clamp screw is inserted into the mounting hole and screwed into the tool body. When the head presses the inner periphery of the mounting hole and the insert is attached to the tool body, the head moves from the upper opening edge of the mounting hole to the lower surface of the insert body in this mounting state. It is desirable to be configured to be immersive to the side. As a result, as described above, the chips that have flowed into the space above the opening on the upper surface side of the mounting hole from the recess collide with the clamp screw head and hinder smooth discharge, or the clamp screw head is worn out. It is possible to prevent the engagement hole with a wrench or the like provided on the upper surface from being crushed.

  FIGS. 1 to 7 show an embodiment of the insert of the present invention, and FIGS. 8 to 11 show an embodiment of the cutting tool of the present invention to which the insert of this embodiment is attached. The insert of the present embodiment has a flat plate shape in which the insert body 1 is formed of a hard material such as cemented carbide and the outer shape is a substantially regular triangle (more strictly, a hexagonal shape). It is composed of upper and lower surfaces 2 and 3 and three side surfaces 4 arranged around the upper and lower surfaces 2 and 3.

  Further, the insert body 1 is opened at the center of the upper and lower surfaces 2 and 3, and the insert body 1 is disposed in the thickness direction (a direction perpendicular to the drawing in FIG. 2; the vertical direction in FIGS. 3 and 5 to 7). 4, a mounting hole 5 having a circular cross-section is formed to penetrate the left and right direction (hereinafter referred to as the insert thickness direction), and the insert body 1 is 120 ° apart from the center line C of the mounting hole 5. It is substantially formed to be rotationally symmetric. As shown in FIG. 4, the inner periphery of the mounting hole 5 is a large diameter portion that is reduced in diameter by a constant taper angle from the opening edge 5A on the upper surface 2 side toward the lower surface 3 side or has a constant inner diameter. 5B, a reduced diameter portion 5C that decreases in diameter toward the lower surface 3 side so as to form a convex curve shape in which a cross section including the center line C protrudes from the large diameter portion 5B toward the inner peripheral side, and the reduced diameter portion The small-diameter portion 5D having a constant inner diameter reaching the lower surface 3 from 5C. Further, the lower surface 3 of the insert body 1 is formed so as to form a substantially similar shape that is slightly smaller than the upper surface 2, and is a flat surface perpendicular to the insert thickness direction. As it goes from the upper surface 2 toward the lower surface 3, the entire surface is inclined toward the inner side of the insert body 1.

  As described above, the rake face 6 is formed at each of the three corners of the upper surface 2 forming a substantially equilateral triangle, and the corner blade 7 is formed at the tip of the corner where the rake face 6 is formed. At the same time, a cutting edge 8 is formed on one side ridge 6A of the rake face 6 connected to one end (the end on the clockwise direction centering on the center line C in FIG. 2) 7A. . Therefore, a portion of the side surface 4 that is continuous with the corner blade 7 and the cutting blade 8 is a flank 4A. In the insert of this embodiment, the side surface 4 on which the flank 4A is formed is on the side of the lower surface 3 as described above. By being inclined toward the inner side of the insert body 1 as it goes to the positive insert, the corner blade 7 and the cutting blade 8 are positive inserts with clearance angles, and the rotational symmetry is 120 ° with respect to the center line C. With the three sets of corner blades 7 and cutting blades 8 arranged, one insert body 1 can be used three times.

  Here, the said corner blade 7 is formed in the convex curve shape which makes a substantially convex circular arc in the planar view seen from the upper surface 2 side along the centerline C. FIG. Further, as shown in FIG. 2, the cutting edge 8 is formed in a polygonal line shape including a plurality of (three in the present embodiment) straight lines that intersect each other at an obtuse angle as shown in FIG. 2. And among these, the main cutting edge 9 is formed by the 1st linear part 9A and the 2nd 2nd linear part 9B of the cutting edge 8 which follow the one end 7A of the corner blade 7, and the said cutting edge 8 The third linear portion that reaches the end P on the opposite side of the corner edge 7 of the one side ridge 6A of the rake face 6 on which is formed is a sub-cutting edge 10.

  Therefore, the secondary cutting edge 10 extends so as to recede to the inner side of the upper surface 2 with respect to the extension line of the main cutting edge 9 at the intersection 8A of the main cutting edge 9 with the second linear portion 9B of the cutting edge 8. It will be. The secondary cutting edge 10 is formed so as to extend substantially at the center of the three sides of the substantially equilateral triangle formed by the upper surface 2. Therefore, the end of the secondary cutting edge 10 on the side opposite to the intersection 8A. That is, the end P of the rake face 6 on the side opposite to the corner edge 7 of the one side edge 6A is a corner edge where the auxiliary cutting edge 10 continues from the midpoint of the side as shown in FIG. 7 is located on the opposite side. Further, the auxiliary cutting edge 10 may have a convex curve shape such as a convex arc having a large curvature radius.

  Furthermore, the other end of the corner blade 7 opposite to the one side ridge 6A where the cutting edge 8 is formed (the end on the counterclockwise direction centering on the center line C in FIG. 2) 7B. In the present embodiment, a dent 11 is formed in the other side ridge 6B of the rake face 6 that is continuous with the rake face 6. The recess 11 is formed by cutting the peripheral surface 4 of the insert main body 1 connected to the other side ridge 6B from the scooping surface 6 to the lower surface 3 by the recess 11A. From the position adjacent to the corner blade 7 directly from the other end 7B or slightly spaced from the other end 7B. The other side edge 6B is formed to a position beyond the center. In this embodiment, the recess 11 has a bottom 11B extending in parallel to the tangent in the plan view, and an end 11C extending in a concave curve from both ends of the bottom 11B and extending toward the other side ridge 6B. However, the entire recess 11 including the bottom 11B may be formed in a concave curve.

  The other side ridge 6B other than the recess 11 is formed so as to extend along the tangent line at the other end 7B of the corner blade 7, and the other side opposite to the corner blade 7 is formed. In the present embodiment, the end Q of the ridge 6B is the above-mentioned one side ridge 6A of the rake face 6 at the other corner adjacent to the corner where the corner blade 7 is formed in the circumferential direction of the upper surface 2. It is made to correspond with the edge part P. FIG. Here, the one side ridge portion 6A and the other side ridge portion 6B of the adjacent corner portions where the end portions P and Q on the opposite side to the corner blade 7 are made to coincide with each other are the end portions. In this embodiment in which the secondary cutting edge 10 is formed on the end P side, the secondary cutting edge 10 intersects the other adjacent side ridge 6B at an obtuse angle. It has been made. Therefore, if the cutting edge 8 of one side ridge portion 6A including the sub-cutting edge 10 is one side, in the present embodiment, the insert body 1 is more precisely the hexagonal top surface 2 as described above. It will exhibit a flat plate shape.

  On the other hand, on the inner side of the other side ridge portion 6B, the rake face 6 is formed with a convex portion 12 having an upper end surface 12A continuous with the other side ridge portion 6B. In this embodiment, the convex portion 12 has its upper end surface 12A extending from the other side ridge portion 6A along the plane S perpendicular to the insert thickness direction to the inside of the rake face 6 as shown in FIG. Further, in the plan view, the upper end surface 12A has a substantially trapezoidal shape in which the width gradually decreases from the other side ridge 6B toward the center line C inside the rake face 6. It is formed to make. Further, the inner portion of the upper surface 2 in the plan view of the convex portion 12 falls one step in the insert thickness direction from the upper end surface 12A as shown in FIG. 7 and enters the opening edge 5A on the upper surface 2 side of the mounting hole 5. Accordingly, the opening edge 5A is positioned on the lower surface 3 side of the insert body 1 with respect to the upper end surface 12A of the convex portion 12. In this embodiment, the opening edge 5A on the upper surface 2 side of the mounting hole 5 has an annular shape having a certain small width in the plan view, and is wider than the plane S over the entire circumference. It is located on another plane V perpendicular to the insert thickness direction located on the lower surface 3 side.

  And the recessed part 13 which becomes recessed with respect to this convex part 12 is formed inside the part from the corner blade 7 to the cutting edge 8 other than the said convex part 12 among the rake faces 6, This recessed part The bottom surface 14 of 13 is formed so as to extend toward the lower surface 3 side toward the mounting hole 5 side inside the rake surface 6 and reach the opening edge 5A on the upper surface 2 side of the mounting hole 5; That is, the bottom surface 14 gradually extends toward the lower surface 3 side toward the mounting hole 5 side, reaches the height of the other plane V in the insert thickness direction, and is not recessed toward the lower surface 3 side than the plane V. Has been. Therefore, between the concave portion 13 and the convex portion 12, the standing wall surface 13A that stands up from the bottom surface 14 and reaches the upper end surface 12A of the convex portion 12 is seen from the inside of the other end 7B of the corner blade 7 in the plan view. It is formed so as to extend toward the center line C of the mounting hole 5, and the standing wall surface 13 </ b> A is inclined so as to recede toward the convex portion 12 side toward the upper end surface 12 </ b> A side.

  Further, as described above, the rake faces 6 formed at the corners adjacent to each other in the circumferential direction of the upper face 2, the end P of one side ridge 6 </ b> A of the rake face 6 and the other rake face 6. In the insert of the present embodiment in which the end portion Q of the other side ridge portion 6B is made to coincide, these are made to coincide with each other in plan view on the opposite side of the standing wall 13A with the concave portion 12 therebetween. The standing wall surface 13B extending from the inner side of the end portions P and Q toward the center line C extends from the bottom surface 14 of the concave portion 13 formed on the one rake surface 6 to the upper end surface 12A of the convex portion 12 of the other rake surface 6. The standing wall surface 13B is also inclined so as to recede toward the convex portion 12 side toward the upper end surface 12A side of the convex portion 12 in the other rake face 6. Yes. However, the standing wall surface 13B is formed so as to extend toward the center line C from a position slightly shifted to the other rake face 6 side from the coincident ends P and Q in the plan view. .

  In addition, the concave portion 13 in the present embodiment is formed so as to be concave on the inner side from a position slightly spaced from the corner blade 7 and the cutting edge 8 on the rake face 6 so that the bottom surface 14 faces the lower surface 3 side. The interval between the recess 13 and the corner blade 7 and the cutting edge 8 is substantially constant width W from the corner blade 7 to the cutting edge 8 and is flush with the upper end surface 12A of the protrusion 12. That is, the flat surface 15 extends along the plane S perpendicular to the insert thickness direction. Therefore, in this embodiment, as shown in FIG. 3, the corner edge 7 and the cutting edge 8 and the other side ridge 6 </ b> B of the rake face 6 have an insert thickness where the flat face 15 and the upper end face 12 </ b> A are located. The edge P and the other side ridge of one side ridge 6A between the rake faces 6 of the corners adjacent to each other in the circumferential direction of the upper surface 2 are positioned on the plane S perpendicular to the vertical direction. In the present embodiment, the corner blades 7, the cutting edges 8, and the other side ridges 6 </ b> B of all the rake faces 6 on the upper surface 2 are continuously arranged by matching the end Q of the portion 6 </ b> B. The flat surface 15 that is located on the plane S and is also located on the plane S and the upper end surface 12A of the convex portion 12 are formed in a frame shape on the periphery of the upper surface 2 as shown in FIGS. The attachment hole 5 and the recess 13 are formed inside the frame.

  Further, on the bottom surface 14 of the concave portion 13, the cross section perpendicular to the corner blade 7 or the cutting edge 8 forms a convex curve on the corner blade 7 and the cutting edge 8 side as shown in FIGS. 5 and 6. Thus, a convex curved surface portion 16 is formed which is directed toward the lower surface 3 as it is directed toward the mounting hole 5. In the present embodiment, the convex curved surface portion 16 is such that the convex curve forms a substantially convex arc, and the convex arc is a straight line perpendicular to the insert thickness direction formed by the flat surface 15 in the same cross section. It smoothly touches (a straight line formed by the plane S in the same cross section). Further, the radius of the convex arc (the radius of curvature of the convex curve) R is the boundary between the concave portion 13 and the convex portion 12 on the corner blade 7 side and the concave portion on the auxiliary cutting edge 8 side in the insert of this embodiment. 13 and the cutting edge 8 are made substantially equal over the entire length of the cutting edge 8 except for the boundary between the ridge 12 of the other rake face 6 adjacent thereto.

  Furthermore, on the bottom surface 14 of the concave portion 13, a cross section perpendicular to the corner blade 7 or the cutting blade 8 is concave on the opening edge 5 A side on the top surface 2 side of the mounting hole 5 further inside the convex curved surface portion 16. A concave curved surface portion 17 is formed so as to form a curved line and further toward the lower surface 3 side of the insert body 1 from the convex curved surface portion 16 toward the mounting hole 5 side. In the present embodiment, the concave curved surface portion 17 is also formed so that the concave curve formed by the cross-section is a substantially concave arc. However, the concave arc has its radius (the radius of curvature of the concave curve). ) R is not constant depending on the position of the corner blade 7 or the cutting blade 8, and the connecting portion with the convex arc formed by the convex curved surface portion 16 in the cross section is also a contact (inflection point) having a common tangent to the convex arc. ), Or may be connected via a tangent line, or may be connected such that the concave and convex arcs of each other are bent at an angle at this connecting portion. Further, a flat surface along the plane V may be formed between the concave curved surface portion 17 and the opening edge portion 5 </ b> A on the upper surface 2 side of the mounting hole 5.

  Here, in the present embodiment, the convex arc formed by the cross section of the convex curved surface portion 16 has the same radius R from the corner blade 7 to the cutting edge 8 as described above, while its both ends 16A. , 16B, the angle θ formed with respect to the plane S perpendicular to the insert thickness direction in the cross section is at least a part of the corner blade 7 and the cutting edge 8 different from the other parts. Has been. Moreover, particularly in the present embodiment, from the end P on the opposite side to the corner blade 7 of the one side ridge portion 6A where the cutting edge 8 is formed, the secondary cutting edge 10 and the main cutting edge 9 of the cutting edge 8 are passed. The angle θ formed by the straight line L with respect to the plane S is gradually increased toward the corner blade 7 side.

  That is, in the present embodiment in which the flat surface 15 perpendicular to the insert thickness direction is formed on the corner blade 7 and the cutting blade 8 side, the flat surface 15 forms in the cross section perpendicular to the corner blade 7 or the cutting blade 8. A contact point between the straight line perpendicular to the insert thickness direction and the convex arc, that is, one end 16A of the convex arc, and a connecting point between the concave arc formed by the concave curved surface portion 17 and the convex arc in the cross section (the concave and convex arcs are mutually connected). The inflection point if it touches smoothly, the contact point between the tangent and the convex arc if it passes through the tangent, the inflection point if the concave and convex arc is bent at an angle), that is, the convex arc The angle θ formed by the straight line L connecting the other end 16B with respect to the plane S is the corner blade 7 side of the cutting blade 8 as shown in FIG. 5 (first linear portion 9A of the main cutting blade 9). And the cutting edge as shown in FIG. 8, the angle θ2 on the side of the auxiliary cutting edge 10 (second linear portion 9B of the main cutting edge 9) is different from each other, and θ1> θ2.

  The angle θ formed by the straight line L of the convex arc formed by the cross section of the convex curved surface portion 16 with respect to the plane S perpendicular to the insert thickness direction is changed in the cross section. In the embodiment, the connection state is set at the connection portion with the radius r of the concave arc formed by the cross section of the concave curved surface portion 17 according to the position of the corner blade 7 and the cutting blade 8 and the convex arc formed by the convex curved surface portion 16. . That is, the concave curved surface portion 17 is set according to the difference in depression of the convex curved surface portion 16 toward the inner surface of the rake face 6 toward the lower surface 3 due to the difference in the angle θ, and the bottom surface of the concave portion 13 as described above. 14 gradually extends toward the lower surface 3 as it goes toward the mounting hole 5, and does not dent on the lower surface 3 side from the plane V where the opening edge 5 A of the mounting hole 5 is located in the insert thickness direction. Has been made.

  In this embodiment, the corner blade 7 and the corner blade 7 including the dent 11 and the cutting blade 8 formed on one side ridge 6A of the rake face 6 connected to the one end 7A of the corner blade 7 are described. A honing 18 is also applied to the other side ridge 6B of the rake face 6 connected to the end 7B. As shown in FIGS. 5 to 7, the honing 18 has the flat surface 15 of the rake face 6 or the upper end face 12 </ b> A of the convex part 12 in a cross section perpendicular to the cutting edge 8, the other ridge line part 6 </ b> B, or the corner edge 7. And a plane that intersects the flank 4A, and a complex honing in which a convex curved surface is formed at the intersecting ridge line portion between the plane and the flat surface 15 or the upper end surface 12A and the flank 4A. Further, reference numeral 19 in the figure indicates which of the three sets of corner blades 7 and cutting blades 8 that can be used three times with one insert body 1 as described above is used. It is an index to do.

  The cutting tool of the present embodiment to which the insert configured as described above is attached has a tool body 21 formed in a substantially cylindrical shape with an axis O as the center, and the insert on the outer periphery of the distal end portion of the tool body 21. Is attached in a detachable manner, and the rear end portion of the tool body 21 is attached to the main shaft of the machine tool, and intersects the axis O while being rotated in the rotation direction indicated by T in the drawing around the axis O. By being sent out in the direction of cutting, a processed surface such as a flat portion or a standing wall is formed on the workpiece (cutting target). Here, in the present embodiment, a plurality of (this embodiment) are provided on the outer periphery of the tip of the tool body 21 so that the outer periphery of the tip of the tool body 21 is cut out in an L shape when viewed from the front in the axis O direction as shown in FIG. The shape of the chip pockets 22 is shown in the other figures, but only one is shown and the others are omitted.) The chip pockets 22 are formed at substantially equal intervals in the circumferential direction. A mounting seat 23 is formed on the front end side of the wall surface 22A facing the T side, and the inserts of the above embodiment are respectively mounted on the mounting seat 23.

  The mounting seat 23 is formed as a recess that opens at the tip and outer periphery of the tool body 21, and has a bottom surface 23 </ b> A that is recessed from the wall surface 22 </ b> A to the rear in the rotation direction T, and the bottom surface 23 </ b> A described above. It is comprised from wall surface 23B, 23C and convex part 23D which stand on the wall surface 22A. Of these, the bottom surface 23A has a planar shape that inclines toward the rear side in the rotational direction T toward the rear end side of the tool body 21, and a screw hole 23E is formed in the center of the bottom surface 23A perpendicular to the bottom surface 23A. Has been. Further, the wall surface 23C is positioned on the inner peripheral side of the mounting seat 23 and extends toward the outer peripheral side of the rear end while facing the substantially outer peripheral side from the front end surface of the tool body 21, and the wall surface 23C is positioned on the outer peripheral side of the rear end of the mounting seat 23. It is formed so as to be positioned and extend from the outer peripheral surface of the tool body 21 to the inner peripheral side of the rear end, and at least the portion on the wall surface 22A side is inclined at an angle substantially equal to the inclination of the side surface 4 with respect to the lower surface 3 of the insert body 1. It is supposed to be flat. Further, the convex portion 23 </ b> D is formed between the wall surfaces 23 </ b> B and 23 </ b> C so as to be located on the inner peripheral side of the rear end of the mounting seat 23 and to be convex toward the outer peripheral side of the tip end of the tool body 21.

  In such a mounting seat 23, the insert has one side surface 4 of the insert main body 1 directed toward the distal end side of the tool main body 21, and the upper surface 2 is directed in the rotational direction T, and the lower surface 3 is brought into close contact with the bottom surface 23A. Thus, the cutting edge 8 having the flank 4A on the one side surface 4 is projected to the tip side of the tool body 21, and the corner blade 7 connected to the cutting edge 8 is projected to the outer periphery of the tip part of the tool body 21. The other edge 7 </ b> B of the other edge 7 </ b> B connected to the other end 7 </ b> B of the corner blade 7 is seated so as to face the outer peripheral side of the tool body 21. Here, in each of the cutting blades 8 that are attached to the plurality of mounting seats 23 and are projected to the tip side of the tool main body 21, the mutual sub-cutting blades 10 are perpendicular to the axis O of the tool main body 21. 10 and 11, a positive axial rake angle (however, the flat surface 15 on the inner side of the cutting blade 8 extends above the cutting blade 8 is arranged so as to be positioned substantially on the plane of the first blade. An axial rake angle (α) along the flat surface S and a negative radial rake angle β are given as shown in FIG. Therefore, the convex curved surface portion 16 on the cutting edge 8 side is formed on the bottom surface 14 of the concave portion 13 formed so as to face the lower surface 3 side of the insert body 1 toward the mounting hole 5 side inside the cutting edge 8. 11, the axial rake angle is substantially given as the axial rake angle α + θ, and the bottom surface 14 is directed toward the rear side in the rotational direction T toward the rear end side in the axis O direction of the tool body 21. Will be extended.

  At this time, on the other side surface 4 of the insert body 1 on the opposite side to the corner blade 7 projected from the outer periphery of the tip end portion of the tool body 21, the flank 4A is brought into contact with the wall surface 23B of the mounting seat 23. In addition, the convex portion 23D is engaged with the concave portion 11A of the other side surface 4. However, the wall surface 23B may be brought into contact with the other side surface 4 other than the recess 11A without forming the convex portion 23D. Further, in the remaining side surface 4 facing the outer peripheral side of the tool body 21, the flank 4A is brought into contact with the wall surface 23C, and thus the head 24A is provided in the mounting hole 5 in a state of being seated on the mounting seat 23. By inserting the clamp screw 24 and screwing it into the screw hole 23E, the head 24A of the clamp screw 24 presses the reduced diameter portion 5C of the inner periphery of the mounting hole 5 so that the insert body 1 can be attached to and detached from the tool body 21. Attached to. An escape portion for preventing mutual interference is appropriately formed between the wall surface of the mounting seat 23 other than the wall surfaces 23B and 23C and the convex portion 23D and the side surface 4 of the insert body 1. Furthermore, in this mounted state, the upper end of the head 24A of the clamp screw 24 does not protrude beyond the upper surface 2 side opening edge 5A of the mounting hole 5, and as shown in FIG. It is accommodated in the diameter portion 5B and is immersed in the lower surface 3 side.

  Further, in the present embodiment, in addition to the clamp screw 24, the tool body 21 is provided with a clamp mechanism 25 for ensuring the mounting rigidity of the insert body 1 more reliably. The clamp mechanism 25 is intended to improve the mounting rigidity by pressing the upper surface 2 of the insert body 1 with a clamp piece 26. That is, as shown in FIG. A clamp screw hole 25A and a smaller diameter hole 25B are formed in the wall surface 22A of the pocket 22, and a clamp screw 27 inserted through the center of the clamp piece 26 is attached to the clamp screw hole 25A. The hole 20B is configured such that the coil spring 28 is accommodated and the pin portion 26A on the rear end side of the clamp piece 26 is inserted.

  And the front-end | tip 26B of the clamp piece 26 is extended even to the scoop surface 6 which will be located in the rear-end side of the tool main body 21 among the upper surfaces 2 of the insert main body 1, and clamp screw 27 is clamp screw. By screwing and tightening into the hole 25A, the tip 26B of the clamp piece 26 presses the upper end surface 12A of the convex portion 12 on the rake face 6 located on the rear end side of the tool body 21 toward the bottom surface 23A side of the mounting seat 23. Thus, the insert body 1 is firmly fixed to the tool body 21. On the other hand, when the clamp screw 27 is loosened, the clamp piece 26 is pushed up by the coil spring 28 so that the press of the insert body 1 is quickly released.

  In the insert attached to the tool body 21 as described above, the cutting blade 8 protruded from the corner blade 7 protruding toward the outer peripheral side of the tool body 21 toward the inner peripheral side so as to extend toward the inner peripheral side. A recess 13 is formed on the inner side of the rake face 6 extending from to the convex part 12 formed on the inner side of the other side ridge 6B of the rake face 6 connected to the other end 7B of the corner blade 7. Therefore, the chips generated by the cutting blade 8 from the corner blade 7 are guided into the recess 13 and flow out toward the opening edge 5A of the mounting hole 5 inside the rake face 6 along the bottom surface 14 thereof. It becomes. The opening edge 5A of the mounting hole 5 is positioned closer to the lower surface 3 side of the insert body 1 than the upper end surface 12A of the convex portion 12, and the bottom surface 14 of the concave portion 13 is moved to the lower surface 3 as it goes to the mounting hole 5 side. Since it extends to the side and reaches the opening edge 5A, the chips introduced into the recess 13 are not interrupted at all and flow into the open space on the mounting hole 5 as they are. It is discharged from the surface 6.

  Moreover, a convex portion 12 is formed on the rake face 6 as described above on the inside of the other side ridge portion 6B where the corner blade 7 and the cutting edge 8 are not formed. The convex portion 12 and the concave portion Standing wall surfaces 13A and 13B are formed between the upper wall 13 and the direction of the outflow of the chips guided to the recess 13 by the standing wall surfaces 13A and 13B. It flows into the released space. Therefore, according to the insert having the above-described configuration, the corner blade 7 and the cutting blade 8 can be used even when performing high feed processing in which the rotation speed and feed amount of the tool body 21 are set higher by the cutting tool to which the insert is attached. Can quickly discharge a large amount of chips generated while controlling the discharge direction, which can lead to an increase in cutting resistance due to clogging or stagnation of the chips, or an unstable chip discharge direction. Thus, it is possible to promote efficient and high-quality high-feed processing by promoting reliable and smooth chip disposal without damaging the processing surface due to biting or the like.

  Furthermore, in the cutting tool of the present embodiment, in the state where the insert is attached to the tool body 21, the upper end of the head 24A of the clamp screw 24 that is inserted into the attachment hole 5 and clamps the insert body 1 to the attachment seat 23, Since the mounting hole 5 does not protrude from the opening edge portion 5A on the upper surface 2 side and is recessed toward the lower surface 3 side than the opening edge portion 5A, as described above, the space from the recess 13 to the mounting hole 5 The chips that have flowed in do not collide with or rub against the head 24A of the clamp screw 24, so that the chips can be discharged more reliably. On the other hand, on the clamp screw 24 side, the head 24A is worn by the collision and abrasion of the chips, and the engagement hole with the work tool such as a wrench formed on the upper surface of the corresponding portion 24A is crushed. There is no possibility that the corner blade 7 and the cutting blade 8 used for cutting will be changed (corner change) or the insert itself may be replaced.

  In addition, in the insert of the present embodiment, rake surfaces 6 are formed at a plurality (three) corners of the upper surface 2 of the polygonal (triangular) flat plate-like insert body 1, and the bottom surface 14 is attached to each of the mounting holes 5. The recesses 13 reaching the upper surface 2 side opening 5A are formed, that is, these recesses 13 communicate with each other through the space on the mounting hole 5. Therefore, by appropriately controlling the outflow direction of the chips by the standing wall surfaces 13A and 13B as described above, for example, in the cutting tool to which the insert of the embodiment is attached, the cutting tool protrudes toward the tip side of the tool body 21 and is used for cutting. Chips generated by the corner blades 7 and the cutting blades 8 are moved from the recesses 13 inside the corner blades 7 and the cutting blades 8 through the space on the mounting holes 5 to the rear end of the tool body 21 of the mounting holes 5. It is also possible to guide to the recess 13 in the other rake face 6 positioned on the outer peripheral side and guide it to the rear end outer peripheral side of the tool body 21 as it is. Can be achieved.

  Further, the insert main body 1 is attached to the tool main body 21 so that the bottom surface 14 of the recess 13 extends toward the rear side in the rotational direction T as it goes toward the rear end side in the axis O direction as described above. In the cutting tool, even if the axial rake angle α of the insert main body 1 itself (the rake angle formed by the plane S with respect to the axis O) is not increased so much, the cutting edge 8 can be protruded toward the tip end side of the tool main body 21. For example, a larger axial rake angle can be provided substantially on the positive angle side by the angle θ. Therefore, since the sharpness of the cutting edge 8 can be improved thereby, the cutting resistance can be further reduced. Therefore, according to the cutting tool configured as described above, the higher feed amount and the tool body 21 as described above can be used. Even in high-feed machining that requires a rotational speed, it is possible to promote more efficient cutting.

  On the other hand, in spite of such a sharp sharpness being imparted to the cutting edge 8, in the insert of the present embodiment, a convex curved surface portion whose section forms a convex curve on the side of the cutting edge 8 of the bottom surface 14 of the concave portion 13. 16 is formed, whereby a large thickness of the insert body 1 around the cutting edge 8 can be secured. The same applies to the corner blade 7, and accordingly, according to the present embodiment, the corner blade 7 and the cutting edge 8 are also used in the above-described high-feed processing in which the burden on the cutting edge 8 and the corner blade 7 is increased. It is possible to prevent the occurrence of defects in the insert and to extend the insert life, and to promote more stable processing. In addition, in the present embodiment, a flat surface 15 perpendicular to the insert thickness direction is formed between the corner blade 7 and the cutting edge 8 and the recess 13, and the cornering blade 7 and the cutting edge 8 themselves have honing 18. Therefore, it is possible to provide an insert having a longer life by further improving the strength around the cutting edge.

  However, in this embodiment, the flat surface 15 is formed on the rake face 6 on the side of the corner blade 7 and the cutting edge 8 in this way, and the corner blade 7 and the cutting edge 8 are honed 18. As shown in FIG. 13, the flat surface 15 is not formed as in the modification shown in FIG. 6, and the concave portion 13 may be formed on the rake face 6 from the inner side of the corner blade 7 or the cutting blade 8 as shown in FIG. In addition, the corner face 7 and the cutting edge 8 may be formed so that the rake face 6 and the flank face 4A intersect with each other directly without being subjected to the honing 18. Furthermore, even if the honing 18 is applied, in this embodiment, the rake face 6 side and the flank face 4A side of the plane intersecting the rake face 6 and the flank face 4A in the cross section orthogonal to the corner blade 7 and the cutting edge 8 are provided. Although the composite honing made into the convex curved surface is given, the angle honing formed only by the plane which cross | intersects the rake face 6 and the flank 4A may be sufficient, and also from the rake face 6 in the said cross section, as shown in FIG. Round honing in which the edge of the corner blade 7 or the cutting edge 8 over the flank 4A is a convex curved surface may be used. In addition, in the modified examples shown in FIGS. 12 to 14, the same reference numerals are assigned to the portions common to the above embodiment in the following modified examples, and the description thereof is omitted.

  Further, when the convex curved surface portion 16 having a convex curved section is formed on the bottom blade 14 of the concave portion 13 on the side of the corner blade 7 or the cutting blade 8 as described above, it is generated by the corner blade 7 or the cutting blade 8. Since chips flow out along the convex curved surface portion 16 of the bottom surface 14 of the concave portion 13, the chips are easily separated from the bottom surface 14. Moreover, in the present embodiment, a concave curved surface portion 17 having a concave curve in cross section is formed on the bottom surface 14 of the concave portion 13 on the opening 5A side on the top surface 2 side of the mounting hole 5, contrary to the convex curved surface portion 16. Therefore, the chips separated from the bottom surface 14 flow into the released space on the mounting hole 5 as they are, and it is possible to promote more smooth and quick chip discharge from the rake face 6 by these. In addition, more efficient and high quality high feed processing can be achieved.

  Further, the curvature radius (radius) R of the convex curve (convex arc) formed by the convex curved surface portion 16 formed on the bottom surface 14 in the cross section orthogonal to the corner blade 7 or the cutting edge 8 is the corner in the insert of this embodiment. The corner blades 7 except for the periphery of the other end 7B of the blade 7 and the periphery of the end portion P of one side ridge 6A where the cutting blade 8 is formed are substantially equal over the entire length of the cutting blade 8. Therefore, the resistance received by the chip flowing out along the convex curved surface portion 16 from the convex curved surface portion 16 is also the width direction of the chip, that is, the end on the side of the cutting blade 8 from the other end 7B of the corner blade 7. The direction extending over the portion P can be made substantially uniform. For this reason, according to the present embodiment, for example, there is a situation in which the resistance received by the chips in the width direction is partly increased or decreased, thereby hindering the control of the outflow direction of the chips as described above. It is possible to prevent the chips from flowing out in a desired direction more reliably and stably.

  However, on the other hand, for example, when such an insert is attached to the cutting tool as described above and particularly high feed machining is performed, it is generated around the auxiliary cutting edge 10 of the cutting edge 8 located on the inner peripheral side of the tip of the tool body 21. While the generated chips are thin and the generation speed is relatively low, thick chips are generated at a high speed around the corner blade 7 projected to the outer peripheral side. If the curvature radius R of the convex curve formed by the cross section of 16 is made constant, chips may be clogged in the concave portion 13 inside the corner blade 7. Therefore, in this embodiment, in addition to making the curvature radius R of the convex curve formed by the cross section of the convex curved surface portion 16 constant in this way, the straight line L passing through both ends of the convex curve is a plane S perpendicular to the insert thickness direction. The angle θ formed with respect to is increased as it goes from the auxiliary cutting edge 10 side of the cutting edge 8 toward the corner cutting edge 7, and at least a part of the corner cutting edge 7 and the cutting edge 8 is different from the other portions. It is said.

  Therefore, according to such an insert, on the corner blade 7 side, the convex curved surface portion 16 on the bottom surface 14 of the concave portion 13 on the inner side thereof is greatly recessed on the lower surface 3 side compared to the sub cutting blade 10 side. Accordingly, it is possible to secure a large amount of recess for accommodating the chips of the concave portion 13 by the convex curved surface portion 16, that is, the pocket capacity. Therefore, even if thick chips are generated at high speed in high feed processing, this corner blade It is possible to prevent chips from becoming clogged in the recess 13 on the 7 side. Further, in the present embodiment, as described above, the cross section perpendicular to the corner blade 7 or the cutting edge 8 is a concave curve (concave) on the opening edge 5A side of the mounting hole 5 on the bottom surface 14 inside the convex curved surface portion 16. Since the concave curved surface portion 17 that forms an arc) is formed, the pocket capacity can be further increased over the entire concave portion 13, and clogging of chips and convection can be more reliably prevented. .

  Moreover, although the pocket capacity by the convex curved surface portion 16 is increased on the corner blade 7 side in this way, in this embodiment, the concave curved surface portion 17 inside the convex curved surface portion 16 has a concave curve ( The radius of curvature (radius) r of the concave arc is not constant from the corner blade 7 to the cutting edge 8, and for example, the concave and convex curves formed by the concave and convex curved surface portions 16 and 17 in the cross section are common tangents. Even when the contact point (inflection point) has a smooth contact, the radius of curvature r of the concave curve portion 17 is small on the corner blade 7 side, and conversely large on the sub-cutting blade 10 side. Thus, the recess 13 can be formed so that the entire bottom surface 14 is not recessed toward the lower surface 3 with respect to the plane V. However, if the concavo-convex curves are connected via a tangent line or are connected so as to bend at an angle to each other, the concave portion 13 is formed so that the bottom surface 14 is not recessed from the plane V even if the curvature radius r is constant. It can also be formed, and there is an advantage that the degree of freedom of design increases.

  In the present embodiment, the curvature radius R is made constant as described above, and the angle θ formed by the straight line L with respect to the plane S perpendicular to the insert thickness direction is set from the side of the auxiliary cutting edge 10 of the cutting edge 8 to the corner. The curvature radius R is changed depending on the cutting conditions and the like, or the angle θ is increased from the corner blade 7 toward the sub cutting edge 10 side, contrary to the above. Or the angle θ may be constant. However, in the case where the angle θ is different from the other portions in at least a part of the corner blade 7 and the cutting blade 8 as described above, of course, for example, when the angle θ is constant. However, if the angle θ is too small, the dent of the recess 3 is also reduced, and there is a risk that prompt chip discharge and stable control of the chip discharge direction may be hindered. On the other hand, even if the angle θ is too large, the recess 13 is excessively dented and the thickness of the insert main body 1 is scraped. In particular, as in the modification shown in FIG. When the flat surface 15 is not formed between the concave portion 13 and the concave portion 13, the blade edge strength may be impaired. Therefore, the angle θ is set within a range of 3 ° to 30 °. desirable.

  On the other hand, in the insert of this embodiment, the dent 11 is formed in the other side ridge 6B of the rake face 6 that is directed to the outer peripheral side of the tool body 21, so that a vertical wall surface is formed on the workpiece. Even in this case, a large clearance can be secured between the wall surface and the other side ridge portion 6B of the insert main body 1. Therefore, it is possible to surely prevent chipping into the portion between the wall portion and the good vertical direction. A wall surface can be obtained. In addition, in the present embodiment, the rake faces 6 formed at the corners adjacent to each other in the circumferential direction of the upper surface 2, the end P of one side ridge part 6 </ b> A of one rake face 6 and the other rake face 6. As shown in FIG. 8, the rake face 6 adjacent to the inner peripheral side of the cutting edge 8 facing the tip side of the tool body 21 is made to coincide with the end Q of the other side ridge 6B. Since the dent 11 of the other side ridge 6B is positioned, the chips generated when the plane is formed by the cutting blade 8 bite into the other side ridge 6B adjacent to the inner peripheral side. In rare cases, it is possible to prevent the processing surface from being damaged, and it is possible to promote higher-quality cutting.

  Moreover, in this embodiment, the said cutting edge 8 is formed in the shape of a broken line with the main cutting edge 9 and the subcutting edge 10 which consist of several linear part 9A, 9B which cross | intersects an obtuse angle. However, this point, for example, the entire cutting edge 8 or the main cutting edge 9 may be formed in a convex curve shape such as a convex arc, but in this embodiment, the overall length of the cutting edge 8 is shortened compared to this. Since cutting resistance can be reduced and fluctuations can be suppressed, chips can be divided at the intersections of the linear portions 9A and 9B and at the intersection 8A between the main cutting edge 9 and the auxiliary cutting edge 10. It becomes possible to achieve more stable chip disposal. Further, in the present embodiment, as described above, the auxiliary cutting edge 10 is formed on the side farthest from the corner edge 7 of the cutting edge 8 (the end P side of one side ridge), and the tool body of the cutting tool When the secondary cutting edge 10 is disposed so as to be along a plane perpendicular to the axis O in the state where it is attached to 21, the bottom surface (plane) of the processing surface can be finished more smoothly by the secondary cutting edge 10. However, in the insert of this embodiment, the cutting edge 8 is thus constituted by the main cutting edge 9 and the auxiliary cutting edge 10, and the main cutting edge 9 is also constituted by a plurality of linear portions 9A and 9B. However, for example, the main cutting edge 9 may be formed by only one linear portion as in the modification shown in FIG. 15, and the auxiliary cutting edge 10 is not formed as in the modification shown in FIG. The entire cutting edge 8 may be constituted by one linear portion.

  Further, in the inserts of these embodiments and modified examples, the insert body 1 has a substantially equilateral triangular flat plate shape as described above, and has a convex portion 12 and a concave portion 13 at three corners of the upper surface 2 thereof. A surface 6 is formed, and at the three sides of the upper surface 2, the end portion P of one side ridge portion 6A and the end portion Q of the other side ridge portion 6B of the adjacent rake surfaces 6 are made to coincide with each other. However, for example, the insert body is formed in a flat plate shape such as a substantially parallelogram, and a rake face having the above-described concavo-convex portion is formed at the corner that forms the acute angle of the rake face of the substantially parallelogram shape. Alternatively, such a rake face may be formed on one or a plurality of, or all of the corners of the upper surface of a rectangular flat plate-like or pentagonal or higher polygon flat plate-like insert body. Furthermore, including the case where the upper surface 2 has a triangular shape as in the present embodiment, one side ridge 6A and the other side ridge 6B of the rake face 6 adjacent to one side of the polygonal upper surface are Even if it exists, the edge part P and Q does not necessarily need to be corresponded, and may be arrange | positioned mutually spaced apart on the said edge | side.

It is a perspective view which shows one Embodiment of the insert of this invention. FIG. 2 is a plan view of the embodiment shown in FIG. 1 viewed from the upper surface 2 side along the center line C. It is a side view of the arrow Y direction view in FIG. It is ZZ sectional drawing in FIG. In the embodiment shown in FIG. 1, it is an expanded sectional view orthogonal to 9 A of 1st linear parts among the main cutting edges 9 of the cutting edge 8. FIG. In the embodiment shown in FIG. 1, it is an expanded sectional view orthogonal to the 2nd linear part 9B among the main cutting edges 9 of the cutting edge 8. FIG. It is an expanded sectional view orthogonal to the other side ridge part 6B of the rake face 6 in embodiment shown in FIG. It is the partially broken side view which looked at the upper surface 2 of the insert main body 1 from the rotation direction T side which shows one Embodiment of the throw-away type cutting tool of this invention which attached the insert of embodiment shown in FIG. It is a bottom view of embodiment shown in FIG. It is ZZ partial side sectional drawing in FIG. It is an expanded sectional view of the periphery of the mounting hole 5 in FIG. It is sectional drawing orthogonal to the corner blade 7 or the cutting blade 8 which shows the modification in case the flat surface 15 is not formed in embodiment shown in FIG. It is sectional drawing orthogonal to the corner blade 7 or the cutting blade 8 which shows the modification in case the honing 18 is not given in embodiment shown in FIG. It is sectional drawing orthogonal to the corner blade 7 or the cutting blade 8 which shows the modification in case honing is round honing in embodiment shown in FIG. It is a top view which shows the modification of the cutting blade 8 of embodiment shown in FIG. It is a top view which shows the other modification of the cutting blade 8 of embodiment shown in FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Insert main body 2 Upper surface of insert main body 4A Flank 5 Mounting hole 5A Opening edge part of the upper surface 2 side of the mounting hole 5 6 Rake face 6A One side ridge part of the rake face 6B The other side ridge part of the rake face 6 7 Corner blade 7A One end of the corner blade 7 7B The other end of the corner blade 7 8 Cutting blade 9 Main cutting blade 9A, 9B Straight portion of the main cutting blade 9 10 Sub cutting blade 12 Convex portion 12A Upper end surface of the convex portion 13 Concavity 13A, 13B Standing wall surface 14 Bottom surface of recess 13 15 Flat surface 16 Convex surface portion 17 Concave surface portion 21 Tool body 23 Mounting seat 24 Clamp screw (clamp member)
24A Head of the clamp screw 24 25 Clamp mechanism 26 Clamp piece C Center line of the mounting hole 5 of the insert body 1 P End of the one side ridge 9A opposite to the corner blade 7 Q of the other side ridge 9B End R on the opposite side of the corner blade 7 R The radius of curvature of the convex curve formed by the convex curved surface portion 16 in the cross section orthogonal to the corner blade 7 or the cutting blade 8 r The concave curved surface portion in the cross section orthogonal to the corner blade 7 or the cutting blade 8 The curvature radius of the concave curve formed by S 17 A plane that includes the corner blade 7 and the cutting edge 8 and is perpendicular to the insert thickness direction V includes the upper surface 2 side opening edge 5A of the mounting hole 5 and is perpendicular to the insert thickness direction Plane L L A straight line passing through both ends of the convex curve formed by the convex curved surface portion 16 in a cross section perpendicular to the corner blade 7 or the cutting edge 8 .theta. (.Theta.1, .theta.2) A straight line L is flat in a cross section perpendicular to the corner blade 7 or the cutting edge 8. For S Angle O rotational direction of the rotation axis T tool body 21 of tool body 21

Claims (9)

  In the insert body having a polygonal flat plate shape, mounting holes are formed in the upper and lower surfaces forming the polygon to penetrate the insert body in the thickness direction. A rake face is formed, a corner blade is formed at the tip of the corner where the rake face is formed, and a cutting edge is formed at one edge of the rake face connected to one end of the corner blade. A convex portion having an upper end surface connected to the other side ridge portion is formed on the rake surface inside the other side ridge portion of the rake surface continuous to the other end of the corner blade. The upper opening edge of the mounting hole is positioned on the lower surface side of the insert body with respect to the upper end surface of the convex portion, while the convex surface is formed on the inner side of the rake face from the corner blade to the cutting edge. The concave part that is concave to the part Made which have the insert bottom surface of the recess, characterized in that it reaches the upper surface opening edge of the mounting hole extends toward the above lower surface side toward the above mounting hole side.   On the corner blade and cutting blade side of the bottom surface of the concave portion, a convex curved surface that faces the lower surface side of the insert body as it goes to the mounting hole side so that a section perpendicular to the corner blade or the cutting blade forms a convex curve. The insert according to claim 1, wherein a portion is formed.   The curvature radius of the convex curve which the said convex curved surface part makes in the cross section orthogonal to the said corner blade or a cutting blade is made substantially equal over the full length of this corner blade and a cutting blade. The described insert.   An angle formed by a straight line passing through both ends of the convex curve formed by the convex curved surface portion in a cross section perpendicular to the corner blade or the cutting edge with respect to a plane perpendicular to the thickness direction is at least a part of the corner blade and the cutting blade. The insert according to claim 2 or 3, wherein the angle is different from that of other portions.   On the upper surface side opening edge side of the mounting hole on the bottom surface of the concave portion, the cross section perpendicular to the corner blade or the cutting blade forms a concave curve and further toward the mounting hole side from the convex curved surface portion. The insert according to any one of claims 2 to 4, wherein a concave curved surface portion is formed toward the lower surface side of the insert main body.   The cutting edge is formed in one straight line connecting one end of the corner blade and the end on the opposite side of the corner blade, or a broken line formed of a plurality of straight lines intersecting each other at an obtuse angle. The insert according to any one of claims 1 to 5, wherein the insert is characterized.   The cutting blade is connected to one end of the corner blade, and reaches the end of the cutting blade opposite to the corner blade, connected to the main cutting blade, and at the intersection with the main cutting blade. The insert according to any one of claims 1 to 6, further comprising a secondary cutting edge that retreats to the inside of the upper surface with respect to an extension line of the main cutting edge.   The insert according to any one of claims 1 to 7, wherein the insert is a positive insert on an outer periphery of a tip portion of a tool body rotated about an axis, and the upper surface of the insert body is directed in a rotation direction of the tool body. The corner blade at the tip of the rake face formed at the corner of the upper surface protrudes to the outer peripheral side of the tip of the tool body and is detachably attached by a clamp member inserted through the attachment hole. In this attached state, the cutting edge formed on the one side ridge portion connected to one end of the corner blade is inclined toward the tip side from the one end of the corner blade toward the inner peripheral side of the tool body. And the other side ridge portion connected to the other end of the corner blade is directed to the inner peripheral side of the tool main body toward the rear end side in the axial direction. The bottom surface of the recess, which is disposed so as to be inclined and is formed on the rake face inside the cutting blade, extends toward the rear side in the rotation direction toward the rear end side in the axial direction. A throw-away type cutting tool characterized by that. The clamp member is a clamp screw having a head, and when the clamp screw is inserted into the mounting hole and screwed into the tool body, the head presses the inner periphery of the mounting hole to insert the insert Is attached to the tool body, and in this attached state, the head portion is immersed in the lower surface side of the insert body from the opening edge of the upper surface side of the attachment hole. Away-type cutting tool.

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