JP2012161907A - Cutting insert, and edge changeable cutting tool - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a cutting insert the mount stability of which is secured when a large cutting load acts on the main cutting blade even if the insert body is formed in a rectangular flat shape, and which can prevent the deterioration of machining accuracy, vibration, and noise from occurring, and also provide an edge changeable cutting tool.SOLUTION: This cutting insert includes an insert body 1. The insert body 1 includes a pair of main surfaces 2 opposite to each other in the thickness direction of the insert body, a pair of long side surfaces 3 opposite to each other in the lateral direction of the main surfaces, and a pair of short side surfaces 4 opposite to each other in the longitudinal direction of the main surfaces. The insert body further includes main cutting blades 5 formed at the intersecting ridges between the main surfaces and the long side surfaces, and auxiliary cutting blades 6 which are formed at the intersecting ridges between the long side surfaces and the short side surfaces and which extend continuously with the main cutting blades. If the short side surfaces 4 of the auxiliary cutting blades are viewed in the thickness direction, a pair of contact surfaces 4B are formed in a recessed V-shape.

Description

The present invention relates to a so-called vertical blade type cutting insert in which a side surface disposed around a surface facing the thickness direction of a long plate-like insert body is a rake surface, and such a cutting insert around an axis. The present invention relates to a blade-tip-exchangeable cutting tool that is detachably attached to an insert mounting seat formed on the outer periphery of a tip end of a rotating tool body.
This application claims priority about Japanese Patent Application No. 2011-007995 for which it applied to Japan on January 18, 2011, and uses the content here.

  As a vertical blade type cutting insert, for example, in Patent Document 1 and Patent Document 2, two end surfaces having a substantially rectangular shape and two side surfaces having a substantially parallelogram shape facing the thickness direction of the insert body are disclosed. And two small side surfaces to form a substantially quadrangular plate shape, but when viewed in the thickness direction facing the side surfaces of the substantially parallelogram, the parallelogram formed by them forms an acute angle portion. And the obtuse angle portion are alternately positioned, and thus, the end face is formed into a concave V-shape that is recessed inside the insert.

  Such a cutting insert described in Patent Documents 1 and 2 is a tool in which one of the two end faces is used as a rake face on an insert mounting seat formed on the outer periphery of a tip portion of a tool body rotated about an axis. A tool with one of the two sides of the substantially parallelogram facing toward the outer periphery of the tool as a peripheral flank and one of the two small sides as a tip flank facing forward in the rotational direction The clamp screw is inserted into an attachment hole that is seated toward the distal end side and is opened so as to open in the center of the side surface of the substantially parallelogram, thereby being detachably attached.

  The cutting insert attached in this way is a rake face as well as the main cutting edge formed at the intersection ridge line portion of the end face that is the rake face and the substantially parallelogram side face that is the outer peripheral flank face. The workpiece is cut by the auxiliary cutting edge formed at the intersection ridge line portion between the end face and the small flank face.

JP-T-2006-508810 (FIG. 1, FIG. 4, FIG. 7) JP-T-2005-528230 gazette (FIGS. 1, 4, 8, 11, and 14)

  These cutting inserts described in Patent Documents 1 and 2 are attached to the insert mounting seat as described above, and the side surface opposite to the side surface defined as the outer peripheral relief surface faces the tool outer peripheral side of the insert mounting seat. It is brought into contact with the bottom surface. Further, the end surface opposite to the end surface which is the rake face is brought into contact with a wall surface facing the front side in the tool rotation direction of the insert mounting seat. The small side surface opposite to the small side surface that is the tip flank is brought into contact with the wall surface of the insert mounting seat that faces the tool tip side and is restrained by the insert mounting seat.

  The small side surface of the insert mounting seat that is brought into contact with the wall surface facing the tool tip side is moved toward the rear side in the tool rotation direction as a clearance angle is given to the small side surface that is the tip clearance surface on the opposite side. It extends so as to incline toward the rear end side of the tool body. Correspondingly, the wall surface facing the tool front end of the insert mounting seat is also inclined to the tool rear end side toward the rear side in the tool rotation direction, so that a large cutting load acts on the main cutting edge and the cutting insert is When strongly pressed to the rear side in the tool rotation direction, the small side surface is separated from the wall surface facing the tool front end side of the insert mounting seat.

  Therefore, in the cutting insert and the cutting edge exchange type cutting tool described in Patent Documents 1 and 2, it is avoided that the mounting is unstable due to the rattling of the cutting insert when such a large cutting load is applied. Therefore, there is a possibility that the processing accuracy is deteriorated or that it is difficult to perform smooth cutting due to vibration and noise. And such a problem is that the cutting length of the main cutting edge is lengthened in order to increase the cutting depth, that is, the cutting in which the insert body has a long plate shape when viewed in the thickness direction. This is particularly noticeable in inserts.

  The present invention was made under such a background, and even when the insert body has a long plate shape, it is possible to ensure mounting stability when a large cutting load acts on the main cutting edge, It aims at providing the cutting insert which can prevent generation | occurrence | production of a process precision deterioration, a vibration, and generation | occurrence | production of noise, and the blade-tip-exchange-type cutting tool which attached the said cutting insert so that attachment or detachment was possible.

The cutting insert of the present invention has an insert body formed in a long plate shape,
The insert body is
A pair of main surfaces (rectangular surfaces) having a long side and a short side and facing in the thickness direction of the insert body;
A pair of long side surfaces that are formed along the length direction in which the long side of the main surface extends, and that face the width direction in which the short side of the main surface extends,
A pair of short side surfaces formed along the width direction of the main surface and facing the length direction of the main surface;
The insert body includes a first center line extending in the thickness direction of the insert body and connecting the centers of the pair of main surfaces, and a pair of the long side surfaces extending in the width direction of the main surface. Each of the second center line connecting the centers and the third center line extending in the length direction of the main surface and connecting the centers of the pair of short side surfaces is formed in a 180 ° rotationally symmetric shape. ,
A main cutting edge is formed on each of the intersecting ridge line portions of the main surface and the long side surface, and the main cutting edge has a rake face on the long side surface and a first flank on the main surface,
Sub-cutting edges are formed at the intersection ridges of the short side and the long side, respectively, and the sub-cutting edges have a rake face on the long side and a second flank on the short side, It is connected to the above main cutting edge,
When viewed from the thickness direction, the short side surface on which the second flank of the sub-cutting blade is formed is directed toward the inside of the main surface toward the center of the short side of the main surface. A pair of abutting surfaces that extend is formed in a concave V shape.

Further, the cutting edge replaceable cutting tool of the present invention has a tool body that is rotated in the tool rotation direction around an axis,
An insert mounting seat is formed on the outer periphery of the tip of the tool body,
The insert mounting seat is a mounting seat bottom surface facing the outer peripheral side of the tool body,
A mounting seat first wall facing the front side in the direction of rotation of the tool;
A mounting seat second wall surface that is inclined toward the tip side of the tool body as it faces the tip side of the tool body and toward the rear side of the tool rotation direction;
The cutting insert is detachably attached to the insert mounting seat, and one of the pair of main surfaces of the insert main body faces the inner peripheral side of the tool main body and contacts the mounting seat bottom surface. Let
One of the pair of long side surfaces is brought into contact with the first wall surface of the mounting seat toward the rear side in the tool rotation direction,
One of the pair of short side surfaces is directed toward the rear end side of the tool body, and one of the pair of contact surfaces of the one short side surface is located on the side opposite to the one long side surface. The contact surface is brought into contact with the second wall surface of the mounting seat.

  In the cutting insert of the present invention, the pair of short side surfaces of the insert body on which the second flank of the secondary cutting edge is formed as described above faces the main surface on which the first flank of the main cutting edge is formed. When viewed in the thickness direction, each is provided with a pair of contact surfaces so as to form a concave V shape. Therefore, at the time of cutting, the short side face is directed to the tool rear end side opposite to the short side face directed to the tool front end side as the second flank face of the auxiliary cutting edge. Further, the one abutment surface of the short side surface is positioned on the opposite side to the one long side surface abutting on the first surface of the mounting seat facing the front side in the tool rotation direction of the insert mounting seat. Therefore, the contact surface located on the front side in the tool rotation direction on the short side surface can be arranged so as to be inclined toward the tip side of the tool body as it goes toward the rear side in the tool rotation direction.

  Like the cutting edge-exchangeable cutting tool of the present invention, the mounting seat second inclined to the tip end side of the tool body as it goes to the rear side in the tool rotation direction, like the one contact surface. Form a wall. By attaching the cutting insert so that the one abutting surface is brought into contact with the second wall surface of the mounting seat, the one abutting surface is moved to the above when the cutting insert is pressed rearward in the tool rotation direction. Strongly pressed by the mounting seat second wall surface. For this reason, the crossed ridge line portion of the long side surface on which the rake face is formed toward the front side in the tool rotation direction and the main surface on which the first flank surface (outer flank surface) is formed is directed toward the tool outer periphery side. Even if a large cutting load is applied to the main cutting edge, it is possible to prevent the mounting stability of the cutting insert from being attached to the insert mounting seat.

  Therefore, according to the cutting insert, for example, when viewed from the thickness direction, the distance between a pair of parallel virtual planes parallel to the thickness direction and in contact with the pair of short side surfaces, and the thickness The ratio between the distance between a pair of parallel virtual planes parallel to the thickness direction and in contact with the pair of long side surfaces when viewed from the thickness direction is within a range of 1.2 to 2.5. Yes. That is, the cutting edge length of the main cutting edge formed in the length direction of the main surface is longer than the length of the short side of the main surface, and therefore the cutting load acting from the main cutting edge tends to be large. Even in this case, it is possible to sufficiently secure the mounting stability to the insert mounting seat, and to improve machining accuracy and prevent vibration and noise during cutting.

  If the concave V-shaped angle formed by the short side surface when viewed from the thickness direction is too large, the short side surface becomes nearly flat when viewed from the thickness direction, and is closer to the tip of the tool body. Depending on the clearance angle given to the short side that is directed and the tip flank, the one contact surface is arranged so as to be inclined toward the tool body tip side toward the rear side in the tool rotation direction. There is a risk that it may be difficult to make contact with the second wall surface of the mounting seat inclined in the direction. However, if the included angle is too small, the crossing angle between the short side surface that is the tip clearance surface and the long side surface that is the rake face of the insert body, that is, the knife angle of the secondary cutting edge becomes small and is missing. Therefore, it is desirable that the included angle of the concave V formed by the short side surface is within a range of 140 ° to 175 °.

  On the other hand, like the cutting inserts described in Patent Documents 1 and 2, one mounting hole through which a clamp screw for mounting the insert body to the tool body is inserted opens at the center of the side surface of the substantially parallelogram. The distance between a pair of virtual planes parallel to each other and in contact with the pair of short side surfaces, particularly when viewed from the thickness direction of the insert main body, as long as it is only provided, In a cutting insert having a large ratio as described above between a pair of parallel virtual planes parallel to the thickness direction and in contact with the pair of long side surfaces when viewed from the thickness direction, When such an excessive cutting load is applied, there is a possibility that the insert body rotates around the center line of the mounting hole and rattling occurs. In addition, when such an insert body is manufactured by press-molding a green compact from raw powder such as a cemented carbide and sintering, the meat between the mounting hole and the long side surface in the green compact is used. Since the difference between the thickness and the wall thickness between the mounting hole and the short side surface becomes remarkably large, the sintered insert body may be deformed or the dimensional accuracy may be lowered.

  The insert body of the present invention is provided with a pair of insert mounting holes that open to the main surface and penetrate the insert body in the thickness direction, and the pair of insert mounting holes has the length of the main surface. It is desirable that they are formed side by side in the direction. As a result, even if a force that rotates the insert body around the center line of one of the insert mounting holes is applied, it is possible to prevent rattling from occurring due to the clamp screw inserted into the other insert mounting hole. Can do. Even when the insert body is manufactured by sintering the green compact as described above, the thickness of the insert body between the insert mounting hole and the long side surface and the short side surface in the green compact, and the insert mounting holes It is possible to avoid a large difference in the thickness between the two and prevent deformation after sintering and deterioration of dimensional accuracy.

  Further, the main surface of the insert main body is formed such that the edge portions on the pair of long side surfaces protrude in the thickness direction with respect to a portion inside the main surface. By this, even if a defect or the like occurs in the main cutting edge formed in the intersecting ridge line portion between the edge and the long side surface, this is suppressed to a portion protruding in the thickness direction of the edge, for example, Further, it is possible to prevent the insert life from being crushed due to the chipping or cracking reaching the insert mounting hole or the long side surface on the opposite side. In addition, when the edge part of a main surface is protruded in this way, what is necessary is just to make the main surface of the inner part of these edge parts contact | abut to the said attachment seat bottom face of an insert attachment seat.

  As described above, according to the cutting insert and the cutting edge replaceable cutting tool of the present invention, even when the cutting length of the main cutting edge of the insert body is long and a large cutting load is applied, the insert mounting of the cutting insert is performed. Stable mounting stability can be ensured, high accuracy of processing can be obtained by suppressing rattling of the insert body, etc., and smooth cutting can be promoted by preventing vibration and noise. It becomes possible.

It is a perspective view which shows one Embodiment of the cutting insert of this invention. It is the side view which looked at the cutting insert shown in FIG. 1 from the thickness direction of the insert main body facing the main surface. It is the front view which looked at the cutting insert shown in FIG. 1 from the direction which opposes the long side surface. It is the top view which looked at the cutting insert shown in FIG. 1 from the direction which opposes the short side surface. It is AA sectional drawing in FIG. It is BB sectional drawing in FIG. It is a perspective view which shows the tool main body in one Embodiment of the blade-tip-exchange-type cutting tool of this invention. It is a perspective view which shows the insert mounting seat of the tool main body shown in FIG. It is a perspective view which shows one Embodiment of the blade-tip-exchange-type cutting tool of this invention which attached the cutting insert of embodiment shown in FIGS. 1-6 to the tool main body shown in FIG. It is the bottom view which looked at the blade-tip-exchange-type cutting tool shown in FIG. 9 from the tool main body front end side. It is a side view of the arrow C direction view in FIG. It is a side view of the arrow D direction view in FIG.

  FIGS. 1-6 shows one Embodiment of the cutting insert of this invention. 7 and 8 show a tool body in one embodiment of the cutting edge-exchangeable cutting tool of the present invention to which the cutting insert of this embodiment is attached. FIGS. 9-12 shows one Embodiment of the blade-tip-exchange-type cutting tool of this invention which attached the cutting insert of embodiment shown in FIGS. 1-6 to this tool main body.

  As for the cutting insert of this embodiment, the insert main body 1 is formed with hard materials, such as a cemented carbide. As shown in FIG. 2, the cutting insert has a long plate shape, and includes a pair of main surfaces 2, a pair of long side surfaces 3, and a pair of short side surfaces 4. The pair of main surfaces 2 face the direction in which the insert mounting hole 8 of the insert main body 1 penetrates, that is, the thickness direction (the horizontal direction in FIGS. 3 and 5; the vertical direction in FIGS. 4 and 6). The pair of long side surfaces 3 are continuous with the long sides (sides extending in the vertical direction in FIG. 2) of the main surface 2. The pair of short side surfaces 4 are continuous with the short sides (sides extending in the left-right direction in FIG. 2) of the main surface 2.

  The insert body 1 includes a center line X extending in the thickness direction of the insert body 1 and connecting the centers of the pair of main surfaces 2, and a pair of long side surfaces 3 extending in the width direction of the main surface 2. Each of the center line Y connecting the centers and the center line Z extending in the length direction of the main surface 2 and connecting the centers of the pair of short side surfaces 4 is formed in a 180 ° rotationally symmetric shape. The center line X is a first center line, the center line Y is a second center line, and the center line Z is a third center line.

  Of these four side surfaces, the crossing ridge line portion between the long side surface 3 and the main surface 2, that is, the long side of the long side surface 3 has a rake face on the long side surface 3. A main cutting edge 5 having a flank is formed, and a cross ridge line portion between the long side surface 3 and the short side surface 4, that is, a short side of the long side surface 3 has a rake face on the long side surface 3. Sub cutting edges 6 having two flank surfaces are formed.

  Among these, the main cutting edge 5 and one of the circumferential directions of the long side face 3 when viewed from the direction facing the long side face 3 with respect to each main cutting edge 5 (in this embodiment, FIG. 3). The secondary cutting edge 6 adjacent to the side in the clockwise direction in FIG. 2 is continuously in contact with a corner blade 7 having a substantially arc shape when viewed from the direction facing the long side surface 3. Accordingly, four sets of continuous main cutting edges 5, corner cutting edges 7 and auxiliary cutting edges 6 are formed in each insert body 1. Further, the intersecting ridge line portion between the main surface 2 and the short side surface 4 where the arcuate corner blade 7 is formed is formed in a cylindrical surface shape.

  The main cutting edge 5 and the sub-cutting edge 6 that form a pair as described above are viewed from the same direction facing the long side surface 3, although the main cutting edge 5 extends substantially linearly over the entire length. On the other hand, the sub cutting edge 6 has a short portion extending to the corner cutting edge 7 extending in a direction substantially perpendicular to the main cutting edge 5, while a portion extending in a direction away from the corner cutting edge 7 is bent slightly at an obtuse angle. The main cutting edge 5 extends in a direction that intersects at a slightly acute angle rather than a right angle. Thereby, as shown in FIG. 3, the long side surface 3 is formed in a substantially parallelogram shape in which the corner portion where the corner blade 7 is formed is an acute angle corner portion.

  However, when viewed from the direction facing the long side surface 3, the auxiliary cutting edge 6 extends so as to be concave on the obtuse angle side of the parallelogram formed by the long side surface 3, and extends to the obtuse angle end portion. The sub cutting edge 6 on the obtuse angle portion side is substantially not used for cutting. In other words, in the present embodiment, the short portion of the auxiliary cutting edge 6 that extends in a direction substantially orthogonal to the main cutting edge 5 connected to the corner edge 7 when viewed from the direction facing the long side surface 3; A portion on the corner blade 7 side of a portion extending in a direction intersecting with this portion and intersecting the main cutting blade 5 at an acute angle is used as the auxiliary cutting blade 6. Accordingly, the portion of the short side surface 4 that is continuous with the sub cutting edge 6 of the short side becomes the second flank 4 A of the sub cutting edge 6.

  Further, the main cutting edge 5, the corner cutting edge 7, and the auxiliary cutting edge 6 that form a pair as described above are arranged in the direction of the center line Y of the long side surface 3 (the horizontal direction in FIGS. 2 and 4). ), The corner blade 7 protrudes the most, and the main cutting edge 5 and the auxiliary cutting edge 6 are formed so as to be recessed in the center line Y direction while drawing a convex curve from both ends of the corner blade 7. Therefore, the long side surface 3 is formed such that the obtuse angle portion opposite to the corner blade 7 is most recessed in the center line Y direction as shown in FIGS. The obtuse angle portion of the auxiliary cutting edge 6 extends so as to be bent from the portion of the convex curve when viewed from the direction facing the short side surface 4 as shown in FIG. It is formed to reach the obtuse angle end.

  Further, as shown in FIG. 3, the pair of long side surfaces 3 of one insert main body 1 have corner blades 7 on one long side 3 opposite to each other when viewed from the direction facing either long side surface 3. The main cutting edges 5 of the long side surfaces 3 intersect with each other at a slight angle so as to protrude from the obtuse angle portion of the parallelogram formed by the long side surface 3 in the direction of the center line Z. The main cutting edges 5 connected to the obtuse angle portion of the long side surface 3 are twisted together around the center line Y so that they protrude slightly from the main cutting edge 5 connected to the corner edge 7 of one long side face 3. Placed in position.

  Further, the first side surface of the long side surface 3 is substantially similar to the long side surface 3 and has a parallelogram shape smaller than the long side surface 3 as shown in FIG. A contact surface 3A is formed. The first contact surface 3A has a flat surface perpendicular to the center line Y. The position in the direction of the center line Y is between the corner blade 7 that protrudes most in the direction of the center line Y and the obtuse angle portion that is recessed most, and the center line Y is more intermediate than the corner blade 7 and the obtuse angle portion. The position is recessed in the direction.

  Further, the main cutting edge 5, the corner edge 7 and the auxiliary cutting edge 6 are inclined toward the inside of the long side surface 3 toward the inside of the long side surface 3 so as to be recessed in the center line Y direction toward the inside. A positive land surface 3B that is recessed and a breaker surface 3C that forms a concave curved surface from the inside of the positive land surface 3B and continues to the first contact surface 3A are formed in this order. At least the positive land surface 3B and the breaker surface 3C form the rake face of the main cutting edge 5, the corner edge 7, and the auxiliary cutting edge 6.

  Of these, as shown in FIG. 6, the breaker surface 3C is located on the inner side in the same manner as the positive land surface 3B at the portion where the inner peripheral edge of the positive land surface 3B protrudes in the center line Y direction from the first contact surface 3A. In the portion where the inner peripheral edge of the positive land surface 3B is recessed in the direction of the center line Y from the first contact surface 3A, the portion of the positive land surface 3B is recessed in the direction of the center line Y. It is bent so as to be recessed.

  On the other hand, each of the pair of main surfaces 2 is formed such that an edge portion 2A on the pair of long side surfaces 3 protrudes in one step in the thickness direction with respect to an inner portion of the main surface 2. Here, these edge portions 2A are formed so as to protrude from the main cutting edge 5 in the thickness direction with a width substantially equal to the center line Y direction, and the protruding surface connected to the main cutting edge 5 is the above-mentioned The first flank 2B of the main cutting edge 5 is provided with a clearance angle so as to be gradually recessed as the distance from the main cutting edge 5 in the direction of the center line Y is increased. Moreover, the part between these edge parts 2A of the main surface 2 is a flat surface perpendicular | vertical to the said thickness direction, ie, orthogonal to the centerline X, and is made into the contact side surface 2C. Therefore, the contact side surface 2 </ b> C is formed in a direction orthogonal to the first contact surface 3 </ b> A of the long side surface 3.

  Further, the insert body 1 is formed with an insert mounting hole 8 penetrating the insert body 1 in the thickness direction, and is opened at the abutting side surface 2C portion of the main surface 2. Here, in the present embodiment, as shown in FIGS. 1, 2, and 5, a pair of insert mounting holes 8 having the same shape and the same size are arranged in the longitudinal direction in which the long side of the main surface 2 extends, that is, the center line Z. It is formed so as to open side by side in the direction.

  These insert attachment holes 8 are for attaching the insert body 1 to the tool body with a clamp screw as will be described later. As shown in FIGS. 5 and 6, the insert mounting hole 8 includes an opening 8A, a contacted portion 8B, and a through portion 8C. The opening 8A is reduced in diameter by a very small constant taper in order from the both abutting side surfaces 2C of the pair of main surfaces 2 toward the inner side in the thickness direction toward the inner side in the thickness direction. The abutted portion 8B has a taper larger than that of the opening portion 8A or a diameter decreasing toward the inner side in the thickness direction so as to form a convex curve in a cross section along the center line of the insert mounting hole 8. The penetrating portion 8C penetrates from the abutted portion 8B having a reduced diameter with a substantially constant inner diameter. Of these, the insert main body 1 is fixed when the head of the clamp screw is brought into contact with and pressed against the contacted portion 8B.

  Further, the short side surface 4 on which the second flank 4A of the auxiliary cutting edge 6 is formed is generally formed on the short side surface 4 when viewed from the thickness direction as shown in FIG. It is formed in a concave V-shape that is recessed inward of the main surface 2 in the center line Z direction toward the center of the short side of the main surface 2. Then, the V-shaped surface that is continuous with the pair of long side surfaces 3 of the short side surface 4 thus formed in the concave V shape is formed with a pair of second flank surfaces 4A that are continuous with the auxiliary cutting edge 6 formed on the long side surface 3. And a pair of second abutting surfaces 4B are formed so as to extend toward the inside of the main surface 2 toward the center of the short side of the main surface 2, respectively. The surface is a contact surface in the present embodiment.

  Here, in each V-shaped surface of the short side surface 4 having the concave V-shape, the second flank 4A connected to the short portion continuous to the corner blade 7 of the auxiliary cutting blade 6 has a width of the short portion. The flat surface is parallel to the center line X extending inside the main surface 2. The second contact surface 4B intersects the second relief surface 4A slightly in an obtuse angle toward the direction away from the corner blade 7 in the same manner as the auxiliary cutting edge 6 and the parallel four sides formed by the long side surface 3. It is formed in a planar shape extending to the obtuse angle portion side of the shape, and its area is larger than the second flank 4A.

  Accordingly, the second abutting surface 4B is in contact with the abutting side surface 2C of the main surface 2 on which the main cutting edge 5 that is paired with the sub-cutting blade 6 that is continuous with the second abutting surface 4B is formed. In a cross section orthogonal to the center line Y, the cross section is formed in a direction that intersects a slightly acute angle rather than a right angle. Further, the second contact surface 4B is orthogonal to the center line X with respect to the first contact surface 3A of the long side surface 3 which is the rake face of the auxiliary cutting blade 6 to which the second contact surface 4B is continuous. While formed in a direction that intersects an acute angle in the cross section, the first contact surface 3A formed on the long side surface 3 on the opposite side crosses the obtuse angle in the cross section that is also orthogonal to the center line X. Formed in the direction.

  The concave V-shaped angle θ formed by the short side surface 4 when viewed from the thickness direction is in the range of 140 ° to 175 °. However, in the present embodiment, the included angle θ is an intersection angle between the second flank surfaces 4A of both V-shaped surfaces of one short side surface 4 when viewed in the thickness direction (centerline X direction). Further, in the concave V-shaped valley bottom portion formed by the short side surface 4, the second flank 4A and the contact surface 4B of both V-shaped surfaces are smoothly connected by the concave curved surface 4C.

  Therefore, the short side 4 along the short side of the main surface 2 has a concave V-shape, so that the main surface 2 of the insert main body 1 of the present embodiment has a rectangular short side that is strictly concave. It will exhibit an eccentric hexagonal shape. Further, in the present embodiment, the main cutting edge 5 along the long side of the main surface 2 also protrudes from the corner blade 7 side in the center line Y direction. Will also have a concave octagonal shape.

  Here, more precisely, the ratio of the long side to the short side of the main surface 2 forming the declination octagon is parallel to the thickness direction when viewed from the thickness direction as shown in FIG. A length L that is a distance between a pair of parallel virtual planes S that are in contact with a pair of short side surfaces 4 and a pair of long side surfaces 3 that are parallel to the thickness direction when viewed from the thickness direction. In this embodiment, the ratio L / M formed by the length M, which is the distance between a pair of virtual planes S ′ parallel to each other, is in the range of 1.2 to 2.5.

  The cutting insert of the present embodiment configured as described above is seated on the insert mounting seat 12 as shown in FIG. 8 of the tool body 11 of the cutting edge exchangeable cutting tool (rolling tool) as shown in FIG. Then, the clamp screw 13 inserted through the insert mounting hole 8 is screwed into the tool main body 11 so as to be detachable, and constitutes a blade-tip-exchangeable cutting tool of the present embodiment as shown in FIGS. To do.

  Here, the tool body 11 of the present embodiment has a substantially disk shape that is vertically long in the direction of the axis O in which the tip portion (the lower portion in FIGS. 11 and 12) is enlarged by one step with the axis O as the center, and the rear end The part is attached to the main shaft of the machine tool and rotated around the axis O to the front side in the tool rotation direction T, while being fed in a direction perpendicular to the axis O, and the workpiece is cut by the cutting insert. A plurality of chip pockets 14 are formed on the outer periphery of the tip end portion of the tool body 11 at intervals in the circumferential direction, and the insert mounting seat 12 is formed on the wall surface on the rear side in the tool rotation direction T of these chip pockets 14. Are formed respectively.

  As shown in FIG. 8, each insert mounting seat 12 has a mounting seat bottom surface 12 </ b> A, a mounting seat first wall surface 12 </ b> B, and a mounting seat second wall surface 12 </ b> C all formed in a planar shape. The mounting seat bottom surface 12 </ b> A faces the outer peripheral side of the tool body 11. The mounting seat first wall surface 12B faces the front side in the tool rotation direction T. The mounting seat second wall surface 12 </ b> C faces the tip side of the tool body 11. Among these, a pair of clamp screw holes 12D into which the clamp screws 13 are screwed are formed in the mounting seat bottom surface 12A so as to be aligned in the axis O direction. Between the mounting seat bottom surface 12A and the mounting seat first and second wall surfaces 12B and 12C, the main cutting blade 5, the auxiliary cutting blade 6, the corner blade 7, and the edge portion 2A of the insert main body 1 are provided. A concave curved surface (concave cylindrical surface) -shaped relief portion 15 is formed to avoid interference.

  The mounting seat bottom surface 12A and the mounting seat first wall surface 12B are formed in directions orthogonal to each other. On the other hand, the mounting seat second wall surface 12C is formed in a direction that intersects the mounting seat bottom surface 12A at a slightly acute angle rather than a right angle in a cross section along a plane parallel to the mounting seat first wall surface 12B. ing. The crossing angle is such that the abutment side surface 2C is in contact with the abutment side surface 2C of the main surface 2 on which the main cutting edge 5 that forms a pair with the sub cutting edge 6 that is continuous with the second abutment surface 4B in the insert body 1 is formed. It is equal to the acute angle made.

  Furthermore, the mounting seat second wall surface 12 </ b> C is formed on the front side in the tool rotation direction T of the insert mounting seat 12, and is inclined toward the tip side of the tool body 11 as it goes to the rear side in the tool rotation direction T. Yes. The mounting seat second wall surface 12C is formed in a direction intersecting with the mounting seat first wall surface 12B at an obtuse angle in a cross section along a plane parallel to the mounting seat bottom surface 12A. The crossing angle between the mounting seat second wall surface 12C and the mounting seat first wall surface 12B is such that the second contact surface 4 of the insert body 1 is the rake face of the auxiliary cutting edge 6 in which the second contact surface 4B is continuous. The obtuse angle of the first abutting surface 3A of the long side surface 3 opposite to the long side surface 3 is equal to the obtuse angle formed in the cross section perpendicular to the center line X.

  In the insert mounting seat 12 formed in this way, the cutting insert of the above embodiment is in contact with one main surface 2 of the pair of main surfaces 2 of the insert main body 1 facing the inner peripheral side of the tool main body 11. The side surface 2C is brought into contact with the mounting seat bottom surface 12A, and one long side surface 3 of the pair of long side surfaces 3 faces the rear side in the tool rotation direction T, and the first contact surface 3A is set to the mounting seat first. The short side surface 4 is brought into contact with the wall surface 12B, and one short side surface 4 of the pair of short side surfaces 4 is directed toward the rear end side of the tool body 11, and the mounting portion of the pair of second contact surfaces 4B of the short side surface 4 is attached. One second contact surface 4B located on the opposite side to the one long side surface 3 in which the first contact surface 3A is in contact with the seat first wall surface 12B is in contact with the mounting seat second wall surface 12C. Let me sit down.

  The cutting insert seated in this way has a pair of clamp screws 13 inserted through the pair of insert mounting holes 8 respectively screwed into the pair of clamp screw holes 12D. Comes into contact with the contacted portion 8B of the insert mounting hole 8 and presses the insert body 1 toward the inner peripheral side of the tool body 11, the rear side in the tool rotation direction T, and the rear end side of the tool body 11, thereby 11 and is detachably attached. Of the pair of second contact surfaces 4B of the one short side surface 4, the other one located on the one long side surface 3 side in which the first contact surface 3A is in contact with the mounting seat first wall surface 12B. The second contact surface 4B and the second flank 4A connected to the second abutment surface 4B are accommodated in a flank 15 formed between the mounting seat second wall surface 12C and the mounting seat first wall surface 12B.

  In the cutting insert attached in this way, the main cutting edge 5 located on the outer peripheral side of the tool body 11 on the other long side surface 3 which is directed to the front side in the tool rotation direction T and is a rake face is used for cutting. The main cutting edge 5 is given a positive axial rake angle as shown in FIG. Further, the auxiliary cutting edge 6 used for cutting in a continuous assembly via the main cutting edge 5 and the corner edge 7 is viewed from the direction facing the long side surface 3 continuously to the corner edge 7. The short part extending in the direction orthogonal to the main cutting edge 5 is positioned on a plane orthogonal to the axis O.

  Note that the main cutting edge 5 and the auxiliary cutting edge of the one long side surface 3 abutted against the mounting seat first wall surface 12B on the side opposite to the main cutting edge 5 and the auxiliary cutting edge 6 used for these cuttings. 6, the corner blade 7 or the obtuse angle portion is formed with the first flank (outer flank) 2B of the main cutting edge 5 used for cutting, and the other main surface 2 directed toward the outer rim side of the tool body 11. Further, the second flank (tip flank) 4A of the auxiliary cutting edge 6 that is also used for cutting is formed, and an appropriate flank angle is given to the other short side surface 4 directed toward the tip side of the tool body 11. Therefore, it does not interfere with the work material.

  Thus, in the cutting insert having the above-described configuration, the direction in which one short side surface 4 facing the rear end side of the tool body 11 faces the main surface 2 in a state of being attached to the insert mounting seat 12 of the tool body 11. And a pair of second contact surfaces (contact surfaces) 4B. The direction in which the short side surface 4 extends as a whole is the rear side of the tool body 11 toward the rear side of the tool rotation direction T in order to give a clearance angle to the other short side surface 4 directed toward the tip side of the tool body 11 as described above. Even in the direction toward the end side, of the pair of second contact surfaces 4B, the tool rotation direction on the opposite side to the one long side surface 3 that contacts the mounting seat first wall surface 12B of the insert mounting seat 12 One second contact surface 4B located on the front side of T may be disposed so as to be inclined toward the tip side of the tool body 11 as it goes to the rear side in the tool rotation direction T as shown in FIG. it can.

  Accordingly, the one of the insert mounting seats 12 of the tool body 11 is in contact with the second contact surface 4B that is inclined toward the tip side of the tool body 11 as it goes rearward in the tool rotation direction T. The mounting seat second wall surface 12 </ b> C that contacts the short side surface 4 is also formed to be inclined toward the tip side of the tool body 11. As a result, even when a large cutting load acts on the main cutting edge 5 during cutting and the insert body 1 is pressed backward in the tool rotation direction T, this one second contact surface 4B is used as the mounting seat second wall surface. The insert main body 1 can be stably held together with the contact of the first contact surface 3A with the mounting seat first wall surface 12B.

  For this reason, according to the cutting insert and the cutting edge exchangeable cutting tool having the above-described configuration, even when the cutting edge length of the main cutting edge 5 is long and a large cutting load is applied at the time of deep cutting, the mounting stability of the cutting insert is improved. Sufficiently securing the insert main body 1 during the cutting process can be prevented. As a result, machining accuracy can be improved, and smooth cutting can be performed while preventing generation of vibration and noise. This is, for example, the distance between a pair of virtual planes S parallel to each other and in contact with the pair of short side surfaces 4 when viewed from the thickness direction of the insert body 1 as in the present embodiment. A certain length L and a length M that is a distance between a pair of parallel virtual planes S ′ parallel to the thickness direction and in contact with the pair of long side surfaces 3 when viewed from the thickness direction. This is particularly effective when the ratio L / M is as large as 1.2 to 2.5 and the cutting load acting on the main cutting edge 5 formed on the long side of the main surface 2 is large.

  On the other hand, also on the tool body 11 side of the cutting edge exchangeable cutting tool, the second mounting wall surface 12C of the insert mounting seat 12 is formed so as to be inclined toward the tip end side of the tool body 11, as shown in FIG. As shown in FIG. 11, the crossing angle α between the mounting seat second wall surface 12C and the portion 14A intersecting the mounting seat second wall surface 12C among the wall surfaces facing the front side in the tool rotation direction T of the chip pocket 14 is It can be set on the obtuse angle side. For this reason, it is possible to prevent occurrence of a situation in which chipping or the like occurs at these intersecting portions and the mounting stability of the insert body 1 is impaired, and smoother cutting can be promoted. .

  In the present embodiment, of the V-shaped surface of the short side surface 4 having a concave V-shape, the second flank 4A is connected to the second flank 4A continuous with the portion extending in the direction perpendicular to the main cutting edge 5 of the auxiliary cutting edge 6. The area of the 2 abutting surface 4B is made larger, so that the mounting stability of the insert body 1 can be improved.

  In addition, the one second contact surface 4B is formed in a direction that intersects a slightly acute angle rather than a right angle with respect to one contact side surface 2C that contacts the mounting seat bottom surface 12A of the insert mounting seat 12. Accordingly, the mounting seat first wall surface 12B is also formed in a direction crossing an acute angle with respect to the mounting seat bottom surface 12A, so that the insert body 1 is moved to the rear end side of the tool body 11 by the cutting load acting on the auxiliary cutting edge 6. When pressed, a so-called wedge effect acts between the insert body 1 and the insert mounting seat 12. For this reason, according to the present embodiment, it is possible to ensure the mounting stability of the insert body 1 even when an excessive cutting load is applied to the auxiliary cutting edge 6.

  In the present embodiment, the included angle θ of the short side surface 4 formed in the concave V shape as described above is in the range of 140 ° to 175 °. However, if the included angle θ is too large, The side surface 4 is nearly flat when viewed from the direction facing the main surface 2, and the first second contact of the mounting seat second wall surface 12 </ b> C of the insert mounting seat 12 and the one short side surface 4 brought into contact with the mounting seat second wall surface 12 </ b> C. The surface 4B cannot be inclined toward the distal end side of the tool body 11 as it goes rearward in the tool rotation direction T. Alternatively, even if it can be tilted, the tilt angle with respect to a plane perpendicular to the axis O of the tool body 11 becomes gentle, and there is a possibility that the above-described effects cannot be reliably achieved.

  On the other hand, if the included angle θ is too small, the second short side surface 4 of the insert body 1 that is directed toward the tip side of the tool body 11 and serves as a tip flank face is positioned on the front side in the tool rotation direction T. The crossing angle between the two flank surfaces 4A and the other long side surface 3 that is the rake face directed toward the front side in the tool rotation direction T, that is, the knife angle of the auxiliary cutting edge 6 is reduced, and the cutting edge strength is impaired. This tends to cause defects. For this reason, it is desirable that the included angle θ is set within a range of 140 ° to 175 ° as in the present embodiment.

  Further, in the cutting insert of the present embodiment, a pair of insert mounting holes 8 are formed in the insert body 1 so as to be aligned in the direction in which the long side of the main surface 2 extends (centerline Z direction). The pair of clamp screws 13 respectively inserted into the holes 8 are screwed into the pair of clamp screw holes 12D of the insert mounting seat 12 to attach the cutting insert. Therefore, as compared with the case where a single clamp screw is inserted into one mounting hole as in the cutting inserts described in Patent Documents 1 and 2, the clamping force itself is strong, and a large cutting load acts. Even when this is done, rattling does not occur as the insert body 1 rotates around the insert mounting hole 8.

  Moreover, by forming the pair of insert mounting holes 8 in this way for the long plate-shaped insert body 1, the distance between the insert mounting holes 8 and the long and short side surfaces 3, 4 of the insert body 1 and the insert mounting holes. It is possible to avoid a large difference in the wall thickness between the eight members. For this reason, when such an insert body 1 is manufactured by sintering a green compact press-molded from a raw material powder such as a cemented carbide, the difference in thickness of the green compact becomes large. It is also possible to prevent the dimensional accuracy and shape accuracy of the sintered insert body 1 from being impaired due to the difference in the thickness of the green compact.

  On the other hand, in the cutting insert of the present embodiment, the edge portions 2A on the pair of long side surfaces 3 side of the main surface 2 of the insert body 1 protrude in the thickness direction with respect to the contact side surface 2C on the inner side. The first flank 2B of the main cutting edge 5 formed at the intersecting ridge line portion between the main surface 2 and the long side surface 3 is formed on the edge portion 2A. For this reason, even if a large cutting load as described above acts on the main cutting edge 5 and the main cutting edge 5 is chipped, such a chipping, a crack accompanying this, etc. protruded. It is possible to prevent the edge 2A from spreading beyond the edge portion 2A, and avoid the insert mounting hole 8 and the long side surface 3 on the opposite side from being cracked and crushed to shorten the life of the insert. it can.

  According to the cutting insert and the cutting edge replaceable cutting tool of the present invention, even when the cutting length of the main cutting edge of the insert body is long and a large cutting load is applied, the mounting stability of the cutting insert to the insert mounting seat is stable. Can be ensured sufficiently, shakiness etc. of the insert body can be suppressed and high machining accuracy can be obtained, and generation of vibration and noise can be prevented and smooth cutting can be promoted.

1 Insert body 2 Main surface 2A Edge of main surface 2 2B First flank (outer flank)
2C Contact side surface 3 Long side surface 3A First contact surface 4 Short side surface 4A Second flank (tip flank)
4B Second contact surface (contact surface)
5 Main cutting blade 6 Sub cutting blade 7 Corner blade 8 Insert mounting hole 11 Tool body 12 Insert mounting seat 12A Mounting seat bottom surface 12B Mounting seat first wall surface 12C Mounting seat second wall surface 12D Clamp screw hole 13 Clamp screw L A pair of virtual planes Distance between S M Distance between a pair of virtual planes S ′ Axis of the tool body 11 S When viewed from the thickness direction of the insert body 1, it is parallel to the thickness direction and in contact with the pair of short side surfaces 4. A pair of virtual planes S ′ A pair of virtual planes parallel to each other and in contact with the pair of long side surfaces 3 when viewed from the thickness direction of the insert body 1 T Tool rotation direction θ Concave V-shaped The included angle of the short side 4

Claims (6)

A cutting insert having an insert body that forms a long plate shape,
The insert body is
A pair of main surfaces having a long side and a short side and facing in the thickness direction of the insert body;
A pair of long side surfaces that are formed along the length direction in which the long side of the main surface extends, and that face the width direction in which the short side of the main surface extends,
A pair of short side surfaces formed along the width direction of the main surface and facing the length direction of the main surface;
The insert body includes a first center line extending in the thickness direction of the insert body and connecting the centers of the pair of main surfaces, and a pair of the long side surfaces extending in the width direction of the main surface. Each of the second center line connecting the centers and the third center line extending in the length direction of the main surface and connecting the centers of the pair of short side surfaces is formed in a 180 ° rotationally symmetric shape. ,
A main cutting edge is formed on each of the intersecting ridge line portions of the main surface and the long side surface, and the main cutting edge has a rake face on the long side surface and a first flank on the main surface,
Sub-cutting edges are formed at the intersection ridges of the short side and the long side, respectively, and the sub-cutting edges have a rake face on the long side and a second flank on the short side, It is connected to the above main cutting edge,
When viewed from the thickness direction, the short side surface on which the second flank of the sub-cutting blade is formed is directed toward the inside of the main surface toward the center of the short side of the main surface. A cutting insert comprising a pair of extending contact surfaces and having a concave V shape. The cutting insert according to claim 1,
The distance between a pair of parallel virtual planes parallel to the thickness direction and in contact with the pair of short side surfaces when viewed from the thickness direction, and the thickness direction when viewed from the thickness direction. A cutting insert in which a ratio of a distance between a pair of parallel imaginary planes parallel to each other and in contact with the pair of long side surfaces is within a range of 1.2 to 2.5. The cutting insert according to claim 1 or 2,
A cutting insert in which a concave V-shaped angle formed by the short side surface is within a range of 140 ° to 175 ° when viewed from the thickness direction. The cutting insert according to any one of claims 1 to 3,
The insert body is provided with a pair of insert mounting holes that open in the main surface and penetrate the insert body in the thickness direction,
The cutting insert in which the pair of insert mounting holes are formed side by side in the length direction of the main surface. The cutting insert according to any one of claims 1 to 4,
The said main surface is a cutting insert in which the edge part of said pair of long side surface side is formed so that it may protrude in the said thickness direction with respect to the part inside the said main surface. It has a tool body that rotates in the tool rotation direction around the axis,
An insert mounting seat is formed on the outer periphery of the tip of the tool body,
The insert mounting seat is a mounting seat bottom surface facing the outer peripheral side of the tool body,
A mounting seat first wall facing the front side in the direction of rotation of the tool;
A mounting seat second wall surface that is inclined toward the tip side of the tool body as it faces the tip side of the tool body and toward the rear side of the tool rotation direction;
The cutting insert according to any one of claims 1 to 5 is detachably attached to the insert mounting seat, and one of the pair of main surfaces of the insert body is attached to the tool. It is brought into contact with the bottom surface of the mounting seat toward the inner peripheral side of the main body,
One of the pair of long side surfaces is brought into contact with the first wall surface of the mounting seat toward the rear side in the tool rotation direction,
One of the pair of short side surfaces is directed toward the rear end side of the tool body, and one of the pair of contact surfaces of the one short side surface is located on the side opposite to the one long side surface. A cutting edge replaceable cutting tool, wherein the contact surface is in contact with the second wall surface of the mounting seat.

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