JP2008254128A - Cutting insert and insert detachable type rotary cutting tool - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an insert capable of securing wall thickness with a flank of a main cutting edge at a center portion of a side ridge portion closed to a mounting hole in which a clamp screw is inserted, and preventing catching of chips. <P>SOLUTION: A cutting face 2 is formed on one polygon surface of an insert body 1 forming a polygon flat plate shape. On the side ridge portion of the polygon surface, the main cutting edge 7 extending from a corner edge 6 on one end portion side of the side ridge portion toward a corner portion 9 of the other end portion while using a side surface of the insert body 1 as a flank, is formed. On the flank 4, a convex curved surface portion 4B gradually retracting in a convex curved shape toward the other polygon surface side of the insert body 1 on a cross section orthogonal to the side ridge portion is formed. The radius of curvature on the cross section orthogonal to the side ridge portion of the convex curved surface portion 4B is made to be smaller in a center portion than that on the one end portion side and the other end portion side of the side ridge portion. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention is a cutting insert (hereinafter simply referred to as an insert) which is attached to a tool body of an insert detachable rolling tool (hereinafter simply referred to as a rolling tool) and constitutes a cutting blade of the rolling tool. The present invention also relates to a turning tool to which such an insert is attached.

  As an insert and a rolling tool of this type, the inventors of the present invention disclosed in Patent Document 1 that a rake face is formed on one polygonal surface of an insert body having a substantially polygonal flat plate shape. A main cutting edge with the side surface of the insert body as a flank is formed on the side ridge, and the rake face is directed in the tool rotation direction on the tool body of the rolling tool rotated around the axis, and the main cutting edge is formed. The blade is attached so as to extend toward the rear side in the tool rotation direction toward the rear end side on the outer periphery of the tool body, and in this attached state, the projected line of the rotation locus around the axis of the main cutting edge is An insert having a convex arc shape that smoothly contacts the cylindrical surface centered on the axis and goes to the inside of the cylindrical surface toward both ends, and the insert is attached to the tool body as described above. It has proposed possible to the milling tool attachment.

With such inserts and milling tools, even when the milling tool is moved stepwise to form a deep vertical machining surface, the seams between the individual machining surfaces can be made inconspicuous, and the entire vertical machining surface As a result, high precision and surface quality can be obtained, and further high-speed cutting can be performed even with a metal material having high ductility such as aluminum by improving chip separation.
JP 2005-319575 A

  By the way, an insert that is detachably attached to such a rolling tool is usually inserted with a clamp screw because the tool body is rotated at a high speed when processing a material such as aluminum as described above. It is attached to the tool body by being stopped. In the insert described in Patent Document 1 as well, in order to insert the clamp screw into the insert body, a circular mounting hole that penetrates the insert body in the thickness direction is formed at the center of the polygonal surface. It is formed to open.

  However, the insert described in Patent Document 1 specifically has a horizontally long flat plate shape of a parallelogram, and a rake face is formed on the surface forming the parallelogram, and in the longitudinal direction thereof. The main cutting edge is formed at the extending side ridge, and therefore the thickness of the insert body is reduced between the mounting hole and the flank of the main cutting edge at the center of the side ridge near the mounting hole. It is inevitable that the cutting edge strength and the strength of the insert itself are damaged. For this reason, when this insert is used for cutting steel or the like, for example, the main cutting edge may be damaged at the center of the side ridge, or the insert main body may be damaged between the mounting hole.

  Therefore, in such a case, it is desirable to keep the thickness of the flank connected to the main cutting edge as small as possible to ensure the wall thickness and maintain the strength of the cutting edge and the insert body. When the amount is small, the space between the machined surface formed by the main cutting edge and the flank surface becomes small, so when cutting a highly ductile metal material such as aluminum, chipping occurs. Therefore, there is a risk that the high processing accuracy and processing quality as described above may be impaired. Incidentally, in the insert described in Patent Document 1, the flank on the side of the main cutting edge is connected to the main cutting edge, and the first flank is inclined so as to gradually recede toward the seating surface. A second flank that is inclined at an inclination angle and a flat third flank that is perpendicular to the seating surface are formed in a stepped shape so as to ensure the escape amount.

  The present invention has been made under such a background, and even when the mounting hole for inserting the clamp screw is formed as described above, the central portion of the side ridge portion that is particularly close to the mounting hole is provided. In this case, the thickness of the flank of the main cutting edge can be secured, and it is possible to prevent damage even when cutting steel or the like. An object of the present invention is to provide an insert capable of preventing biting, and a turning tool to which the insert is detachably attached.

  In order to solve the above problems and achieve such an object, the insert of the present invention has a rake face formed on one polygonal surface of an insert body having a polygonal flat plate shape, A main cutting edge extending from one end portion of the side ridge portion to the other end portion is formed on the side ridge portion of the square surface with the side surface of the insert main body as a flank surface. In the cross section orthogonal to the section, a convex curved surface portion is formed which gradually recedes in a convex curve shape toward the other polygonal surface side of the insert body, and the curvature radius of the convex curved surface portion in the cross section is the above It is characterized by being made smaller at the center than at one end and the other end of the side ridge.

  Further, in the rolling tool of the present invention, such an insert has the rake face directed in the tool rotation direction on the outer periphery of the tip end of the tool body rotated about the axis, and the one end portion is the tip end of the tool body. The main cutting edge located on the outer peripheral side and extending from the one end is detachably attached so as to move toward the rear side in the tool rotation direction toward the rear end side on the outer periphery of the tool body. Features.

  In the insert configured in this way, first, a convex curved surface portion having a convex curve shape is formed on a flank surface continuous to the main cutting edge in a cross section orthogonal to the side ridge portion where the main cutting edge is formed. Compared with the case where the flank is formed in a stepped shape and the escape amount is ensured as described in Patent Document 1, the thickness of the insert body can be ensured particularly on the main cutting edge side. And since the curvature radius in the said cross section of this convex-curved surface part is made small in the center part rather than the one end part side and other end part side of the said side ridge part, said one polygonal surface in which the rake face was formed Even if the mounting hole for inserting the clamp screw is open at the center of the center, the thickness of the insert body up to the convex curved surface of the flank is at one end side at the center of the side ridge near the mounting hole. And larger than the other end side, the cutting edge strength of the main cutting edge formed at the center of this side ridge and the strength of the insert body between the mounting hole and the flank are improved. You can plan.

  On the other hand, on the other hand, on one end side and the other end side of the side ridge portion, the radius of curvature of the convex curved surface portion is smaller than that of the central portion, and the convex curved surface portion is bent more greatly and retracted. Therefore, it is possible to secure a large space between the machining surface formed by the main cutting edge and the flank surface, and it is possible to prevent chipping. In particular, when the rolling tool is moved stepwise in the axial direction as described above to form a deep vertical machining surface, the periphery of the insert body is positioned on the front end side and the rear end side of the tool body. The one side and the other side of the side ridges that are to be opened tend to bite, but a large space is secured in such a part, so that a highly ductile metal such as aluminum Even when the material is cut, it is possible to more reliably prevent chip biting.

  Here, similarly to the insert described in Patent Document 1, when the one polygonal surface has a parallelogram shape in a plan view facing the one polygonal surface, a main cutting edge is formed. The radius of curvature of the convex curved surface portion at a position that bisects the one polygonal surface in the direction in which the main cutting edge extends is the one end portion of the side ridge portion. As the positions on the side and the other end side, the radius of curvature of the convex curved surface portion at a position that further bisects the bisecting position and both ends of the one polygonal surface in the direction in which the main cutting edge extends. It is desirable to be in the range of 20% to 90%.

  That is, if the radius of curvature of the convex curved portion at the center is smaller than this, the convex curved portion retreats while sharply curving toward the other polygonal surface, and the mounting hole is formed. In some cases, it may be difficult to ensure the thickness of the insert body at the center. On the other hand, even when the radius of curvature of the convex curved surface portion at the center is larger than this range and is close to the curvature radius of the one end side and the other end side, the one end side and the other end side When the escape space is secured, the escape space at the central portion also increases, and there is a possibility that the strength of the main cutting edge and the insert main body at the central portion cannot be ensured.

  In addition, by forming the main cutting edge into a convex curve shape that is convex outward in a plan view facing the one polygonal surface, the flank face connected to the main cutting edge is also directed toward the outside of the rake face. Since it is formed so as to be convex, it is possible to secure a larger thickness up to the flank even if the attachment hole is formed. Further, in this way, the main cutting edge is formed in a convex curve shape, and the main cutting edge is attached so as to extend to the rear side in the tool rotation direction as it goes to the rear end side of the tool body like the rolling tool of the present invention. Thus, like the insert described in Patent Document 1, the projection line of the rotation locus around the axis of the main cutting edge is smoothly in contact with the cylindrical surface centering on the axis at the intermediate portion, and the cylinder as it approaches both ends. High convexity and surface quality can be obtained when the vertical machining surface is formed as described above as a convex arcuate shape that faces the inside of the surface.

  On the other hand, with the other polygonal surface of the insert body as a seating surface, the main cutting edge is curved as it goes from one end of the side ridge to the other end in a side view facing the side of the insert body. By making the convex curve shape toward the seating surface side, the rake face is also a convex curved surface shape along the convex curve, and the main cutting edge that is located on the tool body rear end side in the rolling tool. Since the axial rake angle on the other end side can be increased, chip separation can be improved as in the insert described in Patent Document 1.

  And at this time, the flank, in order from the main cutting edge toward the seating surface side, the torsion surface portion formed so that the flank angle gradually increases from one end of the side ridge to the other end, and The convex curved surface portion and a flat surface portion having a constant width from the seating surface in a direction perpendicular to the seating surface, the one side of the side ridge portion being closer to the width than the width of the flat surface portion. By increasing the sum of the widths of the twisted surface portion and the convex curved surface portion in the direction perpendicular to the seating surface, it is given to the main cutting edge when the flat surface portion is attached to the insert mounting seat of the tool body as a restraint surface. The axial rake angle can be further increased, and further chip separation can be improved to prevent chip biting more effectively.

  As described above, according to the insert and the rolling tool of the present invention, even when the mounting hole is formed in one polygonal surface which is the rake face of the insert main body, the main cutting edge close to the mounting hole The thickness up to the flank in the center of the side ridge where the ridges are formed can be secured, which can improve the cutting edge strength, even if used for cutting steel etc. Stable cutting can be performed without causing damage to the main body. On the other hand, it is possible to secure a large space between the processed surface on one end side and the other end side of this side ridge part, so even when cutting a highly ductile material such as aluminum, biting of chips is prevented. Therefore, it is possible to prevent high-quality cutting with high accuracy by preventing the processing surface from being damaged by the chips.

  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 an insert body 1 made of a hard material such as cemented carbide having a substantially square shape, more specifically, a horizontally long polygonal flat plate shape having a substantially parallelogram shape. A rake face 2 is formed on the outer peripheral side, and the other parallelogram face is a seating face 3 on a tool body 11 to be described later of the rolling tool.

  Furthermore, flank surfaces 4 are formed on the four side surfaces of the insert body 1, and cutting edges are formed at the crossing ridges between the rake surface 2 and the flank surfaces 4. The flank 4 has a clearance angle with respect to the blade. In addition, a mounting hole 5 having a circular cross section that penetrates the insert body 1 in the thickness direction (vertical direction in FIGS. 3 to 7) is opened at the center of both parallelogram surfaces. Is a flat surface extending in a direction perpendicular to the center line C of the mounting hole 5 and the insert body 1 itself is 180 ° rotationally symmetrical about the center line C.

  Of the four corners on the outer circumference of the one parallelogram surface, the corner portion located at the acute end portion of the parallelogram surface is opposed to the one parallelogram surface along the center line C. In a plan view, a corner blade 6 having a substantially convex arc shape of about 1/4 is formed as shown in FIG. Then, a side ridge extending in the longitudinal direction of the one parallelogram surface (the straight line L direction in FIG. 2) from the corner portion where the corner blade 6 is formed, that is, the long side portion of the parallelogram, A main cutting edge 7 extending from one end 6A toward the other end of the side ridge is formed with the corner blade 6 as one end.

  Further, a minor cutting edge 8 is formed on the short side portion of the one parallelogram surface connected to the other end 6B of the corner blade 6. The corner cutting edge 6 and the main and minor cutting edges 7, 8 are connected to the above cutting edge. The blades are designed to be connected smoothly to each other. On the other hand, the corner portion 9 positioned at the obtuse angle end portion of the one parallelogram surface is the other end portion of the side ridge portion where the main cutting edge 7 is formed, and the corner portion 9 is also in the plan view. It has a substantially convex arc shape of about ¼, but its radius is smaller than the radius of the convex arc formed by the corner blade 6, and is on the opposite side of the corner blade 6 from the side connected to the one end 6 </ b> A. It is connected to the cutting edge 7.

  Here, the auxiliary cutting edge 8 is formed in a straight line extending in a direction perpendicular to the longitudinal direction of the insert main body 1 in the plan view (direction of the straight line M in FIG. 2), and the corner blade 6 is also centered on the center line C. It extends on a single vertical plane. Moreover, the part which goes to the corner | angular part 9 from the other end of the auxiliary cutting edge 8 on the opposite side to the auxiliary cutting edge 8 in the short side part in which this auxiliary cutting edge 8 was formed goes to this corner | angular part 9 side. After being recessed so as to be bent inside the insert body 1 in the plan view, the insert body 1 is also formed as a recess 8A that extends perpendicularly to the longitudinal direction of the insert body 1 and reaches the corner 9. As described above, it has a substantially parallelogram flat plate shape.

  In addition, the concave portion 8A has a corner blade 6 facing the corner portion 9 in a side view facing the side surface of the insert body 1 in which the flank 4 connected to the auxiliary cutting edge 8 is formed as shown in FIG. And after drawing back toward the seating surface 3 side while drawing a convex curve that smoothly touches the one plane in which the auxiliary cutting edge 8 extends, both the obtuse angle end portion 9 is closer to the seating surface 3 side than this one plane. It extends on another plane perpendicular to the center line C located. Further, at least the corner blade 6 and the main and auxiliary cutting blades 7 and 8 which are cutting blades are formed with lands having a very small width perpendicular to the center line C in a cross section perpendicular to the respective cutting blades. In this embodiment, the land is formed over the entire circumference of the one parallelogram surface.

  Further, the main cutting edge 7 is formed in a gently convex curved shape that slightly protrudes outside the insert body 1 in the plan view, and an insert in which a flank 4 connected to the main cutting edge 7 is formed. Also in a side view facing the side surface of the main body 1, as shown in FIG. 3, the seat is gradually bent gradually from the corner blade 6 serving as the one end toward the obtuse end corner 9 serving as the other end. The shape is a convex curve toward the surface 3 side. In addition, the curvature radius of the convex curve that the main cutting edge 7 makes in the plan view at an arbitrary point of the main cutting edge 7 is the radius of curvature at this one point of the convex curve that the main cutting edge 7 makes in the side view. That is, the main cutting edge 7 has a convex curve in a plan view that is gentler than a convex curve in a side view in any part, and the curvature radius thereof is a convex arc formed by the corner blade 6 in a plan view. It is sufficiently larger than the radius and the radius of the recess 8A.

  Further, the rake face 2 connected to the corner blade 6 and the main and sub-cutting edges 7 and 8 is an inclined face toward the seating face 3 as it goes toward the inside of the rake face 2 in the plan view. The angle of inclination of the rake face 2 with respect to the seating surface 3 in the direction toward the center is substantially constant, and therefore intersects the cutting edges (corner edge 6, main cutting edge 7, sub-cutting edge 8) along the direction toward the inside. In the cross section, the rake face 2 has a substantially straight shape inclined toward the seating face 3 side. However, the rake face 2 connected to the main cutting edge 7 has an inclination angle with respect to the seating face 3 that gradually decreases from the one end to the other end as shown in FIGS. In addition, the decreasing rate gradually decreases from one end to the other end, and then gradually increases from the middle. Of the surface of the insert main body 1, at least the rake face 2, preferably the entire one of the parallelogram faces, is lapped.

  Further, on the further inner side of the rake surface 2 thus inclined, the inclined surface is formed as shown in FIGS. 5 to 7 from the inclined surface whose cross section is substantially linear as described above. A concave surface 10A having a concave arc shape in section is formed that intersects an obtuse angle with a straight line and is recessed toward the seating surface 3 with respect to the inclined surface. The concave surface 10 </ b> A has a shape and dimension that is substantially smaller than the outer peripheral shape in plan view of the one parallelogram surface of the insert body 1 on which the rake face 2 is formed in plan view. The undulation of the surface 2 that is easy to be uneven in the direction of the center line C of the cutting edge so that the depth from the intersection with the rake surface 2 in the cross section is substantially constant. In accordance with the shape of the center line C, it is formed so as to be continuous in the center line C direction.

  A portion of the concave surface 10A along the main cutting edge 7 is formed so as to extend at substantially equal intervals with the main cutting edge 7, and accordingly, the rake face 2 connected to the main cutting edge 7 between the concave surface 10A. The width (width along a plane perpendicular to the center line C) is substantially constant. Further, the width of the concave surface 10A is substantially constant at the portion along the main cutting edge 7. On the other hand, the widths of the rake face 2 and the concave face 10A inside the auxiliary cutting edge 8 of the corner blade 6 and the portion connected thereto are made larger than the inner portion of the main cutting edge 7. Further, a portion further inside than the concave surface 10A is once raised upward, and then the height in the direction of the center line C is a plane perpendicular to the center line C located between both ends of the main cutting edge 7. The mounting hole 5 has an opening on the one parallelogram surface side formed in the boss surface 10B.

  On the other hand, the side surface of the insert body 1 on which the flank 4 is formed extends from the corner blade 6, the main cutting edge 7, the auxiliary cutting edge 8, the recessed portion 8 </ b> A, and the obtuse corner portion 9 over the entire circumference of the insert body 1. A shape that does not incline or become convex toward the outside of the insert body 1 while reaching the seating surface 3 in the thickness direction, that is, a shape without an undercut. Among these, the side portion connected to the side ridge portion in which the corner blade 6, the sub-cutting blade 8, the concave portion 8 </ b> A, and the obtuse angle end corner portion 9 are formed is described above in the plan view in the circumferential direction of the insert body 1. Are formed so as to be unevenly curved in accordance with the side ridge portion of the one parallelogram surface that is unevenly curved, and among these, the flank 4 connected to the corner blade 6 and the auxiliary cutting edge 8 is formed by these corner blades. 6 and the minor cutting edge 8 have a small clearance angle, and the seating surface 3 has a large clearance angle.

  On the other hand, the flank 4 connected to the main cutting edge 7 is, in order from the main cutting edge 7 to the seating surface 3 side, one end portion of the side ridge portion where the main cutting edge 7 is formed, that is, a corner blade. 6A, the torsional surface portion 4A formed so that the clearance angle gradually increases toward the other end, that is, the corner portion 9, and the seating surface in a cross section intersecting the torsional surface portion 4A at an obtuse angle and perpendicular to the side ridge portion. A convex curved surface portion 4B that gradually recedes in a convex curve shape toward the side 3, and a flat surface portion 4C in which the width HC from the seating surface 3 in the direction perpendicular to the seating surface 3, that is, the thickness direction is constant. It consists of and. The flat surface portion 4 </ b> C has an inclined flat shape that gradually recedes toward the seating surface 3 side at a constant inclination angle with respect to the seating surface 3.

  Further, the torsional surface portion 4A extends along the main cutting edge 7 having a convex curve in side view as described above so that the width in the direction perpendicular to the main cutting edge 7 is substantially constant. The width HB in the thickness direction perpendicular to the seating surface 3 of the convex curved surface portion 4B between the torsion surface portion 4A and the flat surface portion 4C increases along the main cutting edge 7 from the corner blade 6 side toward the corner portion 9 side. Gradually smaller. However, in this embodiment, the corner portion 6 side that becomes one end portion of the side ridge portion, that is, one end portion side of the side ridge portion, specifically, the corner blade 6 in which the main cutting edge 7 is continuous with the corner blade 6. The sum HA + HB of the width HB of the convex curved surface portion 4B and the width HA in the thickness direction perpendicular to the seating surface 3 of the torsion surface portion 4A is larger than the width HC of the flat surface portion 4C. Has been.

  The convex curved surface portion 4B has a curvature radius of the convex curve formed by the convex curved surface portion 4B in a cross section orthogonal to the side ridge portion of the one parallelogram surface from which the main cutting edge 7 extends. As shown in FIG. 6, the radius of curvature RB at the center of the side ridge is made smaller than both the radius of curvature RA on one end of the side ridge and the radius of curvature RC on the other end. Further, in the present embodiment, the convex curved surface at a position (the straight line M in FIG. 2 or the position of the center line C in FIG. 3) that bisects the one parallelogram surface in the straight line L direction in which the main cutting edge 7 extends. The position where the radius of curvature RB of the portion 4B bisects this position and the both ends in the direction in which the main cutting edge 7 of the one parallelogram surface extends, that is, the position of the sub-cutting edge 8, is further divided into two equal parts ( It is in the range of 20% to 90% with respect to both the curvature radii RA and RC of the convex curved surface portion 4B at the positions of the straight lines A and B in FIG.

  More specifically, in the present embodiment, the diameter of the circle inscribed in the cutting edge (main cutting edge 7) with the center line C as the center in the plan view, that is, the one parallelogram surface on which the rake face 2 is formed. The width in the straight line M direction is 6.6 mm, and the length in the straight line L direction (the length in the straight line L direction between the pair of auxiliary cutting edges 8) is 12 mm, whereas the curvature radius RA is 28 mm. The radius of curvature RB is 24 mm, and the radius of curvature RC is 30 mm. Note that the radius of curvature RA on the one end side and the radius of curvature RC on the other end side may be equal to each other, RA <RC as in the present embodiment, or RA> RC on the contrary. In this embodiment, the width HA is 1.86 mm, the width HB is 6.45 mm, and the width HC is 6.80 mm.

  Further, in the flank portion 4 connected to the corner blade 6 and the corner portion 9, the portion connected to the torsion surface portion 4A, the convex curved surface portion 4B, and the flat surface portion 4C has a constant width in the thickness direction, and the corner blade 6 or The corner portion 9 is a conical surface or a cylindrical surface along a ¼ arc formed in the plan view. Furthermore, the flank 4 connected to the auxiliary cutting edge 8 is constituted by two steps of inclined flat portions extending along the auxiliary cutting edge 8, and the side surface portion of the insert body 1 connected to the recess 8A is located on the rake face 2 side. While the concave curved surface is curved along the concave portion 8A, the portion on the side of the seating surface 3 is an inclined flat surface portion 8B that recedes toward the seating surface 3 at a certain tilt angle with respect to the seating surface 3. ing.

  The insert of the present embodiment configured as described above is detachably attached to the tool body 11 as shown in FIGS. 8 to 11 to constitute the turning tool of the present embodiment. The tool body 11 is formed in a substantially cylindrical shape centered on the axis O by a steel material or the like, and the shank portion 11A on the rear end side (right side in FIGS. 9 and 10) is gripped by the spindle of the machine tool and the like around the axis O While being rotated in the tool rotation direction T, it is fed in a direction intersecting the axis O and used for cutting. Here, a pair of chip pockets 12 that are open to the front end surface and extend to the rear end side are formed symmetrically with respect to the axis O on the outer periphery of the front end portion of the tool body 11, and the rotation direction of the tip pocket 12 Insert mounting seats 13 are respectively formed on the front end side of the wall surface facing the T side, and the insert main body 1 of the insert of the above embodiment is attached to these insert mounting seats 13. The tip pocket 12 is formed to extend to the rear side in the rotation direction T as it goes to the rear end side of the tool body 11 as shown in FIG.

  The insert mounting seat 13 is a recess formed so as to be recessed in one step from the wall surface of the chip pocket 12 to the rear side in the rotation direction T, and is a plane that forms a parallelogram that is substantially the same shape and size as the seating surface 3. A mounting seat bottom surface 13A facing the tool rotation direction T, a planar mounting seat wall surface 13B standing on the tool rear end side of the mounting seat bottom surface 13A and facing the tool tip side so as to be connected to the wall surface, and a mounting seat It is also composed of a flat mounting seat wall surface 13C which stands on the inner peripheral side of the tool on the bottom surface 13A and faces the outer peripheral side of the tool. Accordingly, the mounting seat bottom surface 13A is inclined to the rear side in the rotational direction T as it goes to the rear end side of the tool body 11 like the chip pocket 12, and the mounting seat bottom surface 13A includes the insert body. 1 is formed with a screw hole 15 into which the clamp screw 14 is screwed.

  Further, the mounting seat wall surfaces 13B and 13C are inclined with respect to the mounting seat bottom surface 13A so as to gradually recede toward the wall surface side of the chip pocket 12, and the inclination angles thereof are respectively seated on the insert body 1. The inclination angle of the inclined surface portion 8B with respect to the surface 3 and the inclination angle of the flat surface portion 4C are made equal. Further, the width of the mounting seat wall surface 13B in the direction perpendicular to the mounting seat bottom surface 13A is slightly smaller than the width of the inclined flat surface portion 8B in the direction perpendicular to the seating surface 3, and the width of the mounting seat wall surface 13C is also the main cutting edge. 7 is slightly smaller than the width HC of the flat surface portion 4C. Furthermore, at the corner corners on the inner peripheral side of the rear end of the tool body 11 of the mounting seat bottom surface 13A where these mounting seat wall surfaces 13B and 13C intersect, an escape portion (not shown) that avoids interference with the periphery of the corner blade 8 of the insert body 1 is shown. Abbreviation) is formed.

  In such an insert mounting seat 13, the insert body 1 seats the seating surface 3 on the mounting seat bottom surface 13 </ b> A with the one parallelogram surface on which the rake face 2 is formed facing the tool rotation direction T. The plane of the flank 4 of the one main cutting edge 7 connected to the mounting seat wall surface 13B through the inclined flat surface portion 8B connected to the one recessed portion 8A and the auxiliary cutting edge 8 and the corner blade 6 to the one recessed portion 8A. After the portion 4C is brought into contact with the mounting seat wall surface 13C, the clamp screw 14 inserted through the mounting hole 5 is screwed into the screw hole 15, so that the inclined flat surface portion 8B and the flat surface portion 4C are attached to the mounting seat wall surface. 13B and 13C are pressed and fixed. Therefore, the inclined flat surface portion 8B and the flat surface portion 4C that are in contact with the mounting seat wall surfaces 13B and 13C are a restraining surface that restrains rotation around the center line C of the insert body 1 and displacement movement in the direction along the mounting seat bottom surface 13A. Is done.

  Therefore, in the insert body 1 attached in this way, the corner blade 6 opposite to the corner blade 6 connected to the above-described concave portion 8A via the sub-cutting blade 8 is positioned on the outer peripheral side of the tip of the tool body 11, and The main cutting edge 7 opposite to the main cutting edge 7 of 1 is extended to the rear side in the rotation direction T toward the rear end side on the outer periphery of the front end portion of the tool body 11. In addition, the secondary cutting edge 8 connected to the other end 6B of the corner blade 6 is positioned on a plane perpendicular to the axis O of the tool body 11, and the concave portion 8A connected to the secondary cutting edge 8 is in this plane. Arranged to retract. The main cutting edge 7 extending to the outer periphery of the tip end portion of the insert of this embodiment attached to the tool body 11 in this way has a projection line on the plane including the axis O of the rotation locus around the axis O. The cylindrical surface is smoothly in contact with the cylindrical surface centered on the axis O in the central portion, and the cylindrical surface is directed from the central portion toward the one end portion (corner blade 6) side and the other end portion (corner portion 9) side. It is made into the convex arc shape which goes inside.

  Thus, in the insert having the above-described configuration, the flank 4 connected to the main cutting edge 7 is protruded as shown in FIGS. 5 to 7 in a cross section perpendicular to the side ridge where the main cutting edge 7 is formed. Since the curved convex surface portion 4B is formed between the twisted surface portion 4A and the flat surface portion 4C, for example, the flat surface portion 4C is retracted from the twisted surface portion 4A with a steep slope and then retreated with a gentle slope. Compared with the case where the stepped portion is formed so as to be continuous, the section of the insert body 1 in the convex curved surface portion 4B extends over the entire flank 4 in the direction along the side ridge portion because the cross section is convex. The thickness can be increased. For this reason, in the state where the insert is attached to the tool body 11, the main cutting edge 7 is also directed in the direction from the rake surface 2 on which the cutting load acts on the main cutting edge 7 toward the seating surface 3, that is, on the rear side in the tool rotation direction T. A large thickness can be ensured on the rear side of the blade 7, whereby the cutting edge strength of the main cutting edge 7 can be improved.

  Further, in the insert, the insert body 1 is attached to the tool body 11 by the clamp screw 14 inserted through the attachment hole 5 opened in the center of one parallelogram surface on which the rake face 2 is formed. Since the radius of curvature of the convex curve formed by the cross section of the convex curved surface portion 4B is made larger at the central portion of the side ridge portion adjacent to the mounting hole 5 than at the one end portion side and the other end portion side. Then, it is possible to secure a larger thickness of the flank 4 by the convex curved surface portion 4B.

  Therefore, even if the mounting hole 5 is formed in this way, it is possible to prevent the cutting edge strength of the main cutting edge 7 in the central portion adjacent to the mounting hole 5 from being lowered, even when cutting steel or the like. In this central portion, it is possible to prevent the main cutting edge 7 from being damaged or the insert main body 1 from being damaged with respect to the mounting hole 5. Moreover, in the insert of the present embodiment, the main cutting edge 7 is formed in a convex curve shape that is convex outward in a plan view facing the one parallelogram surface, and also by this, the flank 4 in this central portion Therefore, the cutting edge strength can be further improved.

  On the other hand, on the other hand, at one end (corner blade 6) side and the other end (corner portion 9) side of the side ridge portion, the radius of curvature of the convex curve formed by the cross section of the convex curved surface portion 4B compared to the central portion. Is smaller, that is, the convex curved surface portion 4B is curved so as to recede with a steep slope. For this reason, in these parts located in the front end side and the rear end side of the main cutting edge 7 in the mounting state to the tool main body 11 in the said rolling tool, it is between the process surfaces formed by the said main cutting edge 7. A large space can be secured.

  However, when, for example, the tool main body 11 is moved stepwise in the direction of the axis O to form a vertical machining surface with such a rolling tool, the front and rear end portions of the main cutting edge 7 are formed. At least one of them is open to the machined surface cut in the previous stage, and chips are likely to enter, but the insert with the above configuration ensures a particularly large space in these parts, so even if chips enter. It is possible to prevent biting between the insert body 1 and the processed surface. This is particularly effective when chips are generated in a stretched manner and easily enter between the flank 4 and the processed surface, such as when cutting a highly ductile metal material such as aluminum or an aluminum alloy. Therefore, it is possible to prevent the processing surface from being damaged by such biting of chips and the accuracy of the processing surface from being deteriorated or the quality of the processing surface from being impaired.

  Further, in the insert according to the present embodiment, the main cutting edge 7 is formed in a convex curve shape in the plan view as described above, and the central portion of the insert is attached to the tool main body 11 and the central portion is a cylinder centering on the axis O. Even when the tool body 11 is moved stepwise in the direction of the axis O to form a deep vertical machining surface, both ends are formed in a convex arc shape that smoothly contacts the surface and both ends are inward of the cylindrical surface. Higher machined surface quality can be obtained by making the joints between the machined surfaces of the step inconspicuous.

  Here, the radius of curvature of the convex curved surface portion 4B is a central portion that bisects the one parallelogram surface along the side ridge portion in the direction in which the main cutting edge 7 extends as in the present embodiment. One end side and the other end side in which the radius of curvature RB at the position further bisects the bisecting position and both ends in the direction of the side ridge where the main cutting edge 7 of the one parallelogram surface extends It is desirable that the radius of curvature RA is set to be smaller in the range of 20% to 90% of RC, and if the radius of curvature RB in the central portion is smaller than this range, the convex curved surface portion 4B in the central portion is the seating surface 3. Since it will be curled abruptly as it goes to the side, it will recede to the inside of the insert main body 1, so that there is a possibility that the cutting edge strength of the main cutting edge 7 and the strength of the insert main body 1 cannot be reliably ensured.

  On the other hand, when the radius of curvature RB of the convex curved surface portion 4B at the center is larger than the above range and is close to the radii of curvature RA and RC at the one end side and the other end side, the one end side and the other end side When the escape space of the convex curved surface portion 4B is secured, the escape space in the central portion is also increased, and conversely, the cutting blade strength and the like are reduced. There is a possibility that the clearance space between the portion and the other end portion becomes small and chips are bitten.

  Moreover, in this embodiment, the insert main body 1 is made into the shape of a substantially parallelogram flat plate as described above, and the rake face 2 is formed on one of the parallelogram faces, and the longitudinal direction of this parallelogram face ( The radius of curvature RB is set with the position obtained by dividing the length of the straight line L direction in half as the center, and this position and both ends of the parallelogram surface in the longitudinal direction (positions of both auxiliary cutting edges 8). The curvature radii RA and RC are set with the length further divided into two equal positions on the one end side and the other end side. The insert body 1 has a rectangular or square flat plate shape, When the rake face 2 is formed on the rectangular surface or square surface, the position of the rectangular surface or the square surface in the direction along the side ridge where the main cutting edge 7 is formed is bisected. The central part, and the position that bisects this position and both ends of the edge It may be the position of the side and the other end side. Further, even if the main cutting edge 7 is curved in the plan view or the side view as in the present embodiment, the side ridge portion is regarded as a straight line and is a cross section orthogonal to the straight line L, that is, a cross section orthogonal to the straight line L. The curvature radii RA to RC may be set.

  On the other hand, in the present embodiment, the main cutting edge 7 has a convex curve shape in a side view of the insert body 1 on which the flank 4 is formed, and accordingly, the rake face 2 also follows the main cutting edge 7. Therefore, the chips generated by the main cutting edge 7 and curled while rubbing the rake face 2 are lifted from the rake face 2 on both end sides of the side ridge, Moreover, combined with the fact that the rake surface 2 is lapped, the chips can be quickly separated from the rake surface 2. Further, the main cutting edge 7 is inclined so as to be directed toward the seating surface 3 from one end side to the other end side of the side ridge portion, and the main cutting edge 7 has a convex curve shape. Together with this, the axial rake angle of the main cutting edge 7 on the other end side, which is particularly located on the rear side in the tool rotation direction T, can be increased, so that the sharpness at the end of the cutting per blade can be improved. The separation of chips can be made better.

  Further, in the insert of the present embodiment, the seating surface of the torsional surface portion 4A and the convex curved surface portion 4B of the flank 4 connected to the main cutting edge 7 on one end side of the side ridge portion opposite to the other end portion. Since the sum HA + HB of the width HA in the direction perpendicular to 3 and the width HB is made larger than the width HC in the direction perpendicular to the seating surface 3 of the flat surface portion 4C as the constraining surface as described above, If the width HC of the flat surface portion 4C for restraining 1 is the same, the corner blade 6 side directed toward the one end portion side of the main cutting blade 7, that is, the tip end side of the tool body 11, is greatly projected in the tool rotation direction T. The inclination of the main cutting edge 7 in the attached state, that is, the axial rake angle can be further increased. Accordingly, the axial rake angle on the other end side of the main cutting edge 7 is further increased, so that the chip separation is further improved, and the chips flow out in close contact with the surface 2 of the main cutting edge 7 that is easy to contact. It is possible to prevent a situation in which the workpiece is caught between the processed surfaces.

It is a perspective view which shows one Embodiment of the insert of this invention. It is the top view which looked at the insert shown in FIG. 1 from the direction which opposes one parallelogram surface (polygonal surface) in the centerline C direction. It is the side view which looked at the insert shown in FIG. 1 from the direction which opposes the side surface in which the flank 4 of the main cutting edge 7 is formed. It is the side view which looked at the insert shown in FIG. 1 from the direction which opposes the side surface in which the flank 4 of the subcutting blade 8 is formed. It is XX sectional drawing in FIG. It is YY sectional drawing in FIG. It is ZZ sectional drawing in FIG. It is a perspective view showing one embodiment of a turning tool of the present invention. It is the top view which looked at the cutting tool shown in FIG. 8 from the direction which opposes one parallelogram surface in the centerline C direction of one insert. It is the side view which looked at the rolling tool shown in FIG. 8 from the direction which opposes the side surface in which the flank 4 of the main cutting edge 7 of one insert is formed. It is the front view which looked at the cutting tool shown in FIG. 8 from the axis line O direction front end side.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Insert body 2 Rake face 3 Seating surface 4 Relief face 4A Torsion surface part 4B Convex-curved surface part 4C Plane part 5 Mounting hole 6 Corner blade (one end part of the side ridge part where the main cutting edge 7 extends)
7 Main cutting edge 8 Sub cutting edge 9 Obtuse corner of one parallelogram surface of the insert body 1 (the other end of the side ridge extending from the main cutting edge 7)
11 Tool body 13 Insert mounting seat 14 Clamp screw C Center line of the insert body 1 O Tool body 11 axis T Tool rotation direction L Straight line extending in the longitudinal direction of one parallelogram surface of the insert body 1 RA The radius of curvature of the convex curved surface portion 4B on one end side of the extending side ridge portion RB The radius of curvature of the convex curved surface portion 4B at the center of the side ridge portion where the main cutting edge 7 extends RC The other end of the side ridge portion where the main cutting edge 7 extends Radius of curvature of convex curved surface portion 4B on the portion side HA Width of twisted surface portion 4A on one end portion side of the side ridge portion where main cutting edge 7 extends HB of convex curved surface portion 4B on one end portion side of the side ridge portion on which main cutting edge 7 extends Width of the flat portion 4C on one end of the side ridge where the HC main cutting edge 7 extends

Claims (5)

  A rake face is formed on one polygonal surface of the insert body having a polygonal flat plate shape, and one side of the side ridge portion is formed on the side ridge portion of the one polygonal surface with the side surface of the insert body as a relief surface. A main cutting edge extending from the portion toward the other end is formed, and the relief surface has a convex curve shape toward the other polygonal surface side of the insert body in a cross section orthogonal to the side ridge portion. A convex curved surface portion that gradually recedes is formed, and the radius of curvature of the convex curved surface portion in the cross section is smaller at the central portion than at one end side and the other end side of the side ridge portion. Features cutting inserts.   The one polygonal surface has a parallelogram shape in a plan view opposite to the one polygonal surface, and the one polygonal surface is divided into two in the direction in which the main cutting edge extends. The radius of curvature of the convex curved surface portion is equal to 20 of the radius of curvature of the convex curved surface portion at a position where the position at which the main cutting edge of the one polygonal surface extends further bisects. The cutting insert according to claim 1, wherein the cutting insert is in a range of% to 90%.   The cutting insert according to claim 1 or 2, wherein the main cutting edge has a convex curved shape that protrudes outward in a plan view facing the one polygonal surface.   The other polygonal surface of the insert body is a seating surface, and the main cutting edge is curved as it goes from one end of the side ridge to the other end in a side view facing the side of the insert body. However, it is formed in a convex curve shape toward the seating surface side, and the flank surface runs away from one end portion of the side ridge portion to the other end portion in order from the main cutting edge toward the seating surface side. This plane is composed of a torsional surface portion formed so that the angle gradually increases, the convex curved surface portion, and a flat portion having a constant width from the seating surface in a direction perpendicular to the seating surface. The sum of the widths in the direction perpendicular to the seating surface of the twisted surface portion and the convex curved surface portion on one end side of the side ridge portion is made larger than the width of the portion. The cutting insert according to claim 3.   The cutting insert according to any one of claims 1 to 4, wherein the rake face is directed in the tool rotating direction on the outer periphery of the distal end portion of the tool body rotated about an axis, and the one end portion is disposed on the end portion. The main cutting edge that is located on the outer peripheral side of the front end of the tool body and extends from one end thereof is detachably attached so as to go to the rear side in the tool rotation direction toward the rear end side on the outer periphery of the tool body. An insert detachable type rolling tool characterized by that.

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