WO2017150541A1 - Cutting insert and replaceable-edge cutting tool - Google Patents

Abstract

The present invention makes it possible to control the discharging of chips and prevents loss of an insert body and scraping against a head of a clamp screw or a machined wall surface of a work material. The present invention comprises a polygonal plate-shaped insert body (1) provided with first and second polygonal surfaces (2) that are back to back, and a side surface (3) provided on the periphery of the first and second polygonal surfaces (2). A corner edge (5) is formed in a first corner section (C1) of the corner sections of the first polygonal surface (2). A main cutting edge (6) is formed from the corner edge (5) to a second corner section (C2) that is adjacent to the first corner section (C1) in the circumferential direction of the first polygonal surface (2). A secondary cutting edge (7) is formed on the side opposite the side where the main cutting edge (6) extends in the circumferential direction of the first polygonal surface (2) from the corner edge (5). A portion of the corner edge (5) on the main cutting edge (6) side has formed therein a corner edge concave curve section (5A) extending toward the second polygonal surface (2) side while tracing a concave curve that is gradually recessed to the second polygonal surface (2) side going toward the main cutting edge (6).

Description

Cutting insert and cutting edge changeable cutting tool

The present invention relates to a cutting insert that is detachably attached to a cutting edge exchangeable cutting tool, and a cutting edge exchangeable cutting tool to which the cutting insert is detachably attached. This application claims priority on Japanese Patent Application No. 2016-041540 filed in Japan on March 3, 2016 and Japanese Patent Application No. 2016-171161 filed in Japan on September 1, 2016. This is incorporated here.

As such a cutting insert, for example, Patent Document 1 includes a substantially hexagonal plate-like insert body having three main corners and sub-corners alternately on the upper and lower surfaces, and includes three main corners on the upper surface. Among them, in order from the first main corner to the two adjacent sub-corners, the corner blade, the linear sub-cutting blade that inclines toward the lower surface as it moves away from the corner blade, and the sub-cutting blade as it moves away from the sub-cutting blade A so-called unintentional cutting insert in which the main cutting edge inclined toward the lower surface at a large angle is formed, and the portions extending from the first main corner toward two adjacent sub-corners are the same shape. ing.

Japanese Patent No. 5715688

However, the cutting insert described in Patent Document 1 is projected on the outer peripheral side of the tip end of the tool body while the corner blade is projected to the insert mounting seat formed at the tip end portion of the tool body rotated about the axis. Cutting by mounting one set of secondary cutting edge and main cutting edge connected to the corner blade on the outer peripheral side of the tool body, and mounting the other set of secondary cutting edge and main cutting edge on the tip side of the tool body Since the secondary cutting edge located on the outer peripheral side of the tool body is linear, the chips generated by the secondary cutting edge are not easily curled in a string shape, and the upper surface, which is the secondary rake face, extends slightly. It will flow out.

In addition, it is difficult to control the discharge of the chips that have flowed out in this manner. For example, of the three main corners on the upper surface, the remaining two unused main corners other than the main corner used for cutting have chips. If a collision occurs, the insert main body may be damaged at the unused main corner and may not be used for cutting. In addition, if chips scrape the head of the clamp screw that clamps the cutting insert to the insert mounting seat, the clamp screw must be replaced at an early stage. Furthermore, if the chips that have lost control in this way extend further to the outer peripheral side from the auxiliary cutting edge and the main cutting edge directed to the outer peripheral side of the tool body, there is a possibility that the processing wall surface of the work material will be rubbed and damaged.

The present invention is made under such a background, and controls the discharge of chips generated by a cutting blade located on the outer peripheral side of the tool body, so that the chip of the insert body and the head of the clamp screw It is an object of the present invention to provide a cutting insert capable of preventing a work material from rubbing on a processing wall, and a cutting edge exchange type cutting tool to which the cutting insert is detachably attached.

In order to solve the above-described problems and achieve such an object, the cutting insert of the present invention includes first and second polygonal surfaces facing each other and the first and second polygonal surfaces. A polygonal plate-like insert body having a side surface disposed around the first polygonal surface, and the first corner portion of the first polygonal surface has a first polygonal surface. A corner blade having a corner rake surface is formed, and a main blade connected to the corner rake surface extends from the corner blade to a second corner portion adjacent to the first corner portion in the circumferential direction of the first polygonal surface. A main cutting edge having a rake face on the first polygonal surface is formed, and on the side opposite to the side where the main cutting edge extends from the corner blade in the circumferential direction of the first polygonal surface, The secondary rake face connected to the corner rake face is defined as the first polygonal face. A secondary cutting edge is formed, and a portion of the corner blade on the side of the main cutting edge is drawn with a concave curve that is recessed toward the second polygonal surface toward the main cutting edge. A corner blade concave curve portion extending toward the polygonal surface side is formed.

Further, the cutting edge replaceable cutting tool of the present invention has an insert mounting seat formed on an outer periphery of a tip portion of a tool body rotated about an axis, the cutting insert having the above-described configuration, and the corner blade and the outer periphery of the tip end of the tool body. The main cutting edge connected to the corner blade is positioned on the outer peripheral side of the tool body, and the auxiliary cutting edge is positioned on the tip side of the tool body, and the corner blade, the main cutting edge, and The corner rake face, the main rake face, and the auxiliary rake face connected to the auxiliary cutting edge are detachably attached to the tool rotating direction.

Thus, in the cutting insert of the said structure attached to a tool main body, a 2nd polygonal surface is provided in the main cutting blade side part turned to the tool main body outer peripheral side of the corner blade protruded to the front-end | tip outer peripheral side of the tool main body. A corner blade concave curve portion extending toward the second polygonal surface side while forming a concave curve recessed toward the side is formed. Therefore, the tool main body front end side part of the chip | tip produced | generated with a corner blade and a main cutting blade will be produced | generated by this corner blade concave curve part.

The chip generated by the concave curved corner portion thus forming a concave curved shape is curled with a small radius and curled with a small radius when its tip is bent into a concave curved cross section, and the main rake face It is controlled so as to extend toward the second corner portion in a string form along the main rake face and to be discharged from the bent second corner portion. For this reason, even if there is another first corner portion in which a corner blade is formed on the first polygonal surface, the chips collide with other unused first corner portions and the insert body is damaged. In addition, it is possible to avoid scraping of chips on the head of the clamp screw and the work wall surface of the work material.

Furthermore, a convex curved surface portion that is convex on the side opposite to the second polygonal surface in the direction along the secondary cutting edge is formed on the secondary rake face inside the concave curved portion of the corner blade. Thus, the tip of the chip generated by the concave curved portion of the corner blade can be brought into sliding contact with the convex curved surface portion to give resistance to the chip, and also with this resistance, the chip is curled to a small radius to form a string winding shape. The discharge can be controlled to extend. For this reason, it is possible to more reliably prevent the insert body from being lost, and prevent deterioration of the machined surface roughness due to early replacement of the clamp screw due to rubbing on the head and rubbing against the machining wall surface.

The insert body has a rotationally symmetric shape by 120 ° around the insert center line passing through the centers of the first and second polygonal surfaces, and is reversely symmetric with respect to the first and second polygonal surfaces. Each of the first and second polygonal surfaces has three first and second corner portions alternately arranged in the circumferential direction, and the insert center line is formed in a hexagonal plate shape. The first and second polygonal surfaces are arranged opposite to each other in the direction, and the main cutting edge and the auxiliary cutting edge extend in opposite directions in the circumferential direction of the insert body from the corner blade. By forming the first and second polygonal surfaces (hexagonal surfaces) three times each on the front and back sides with one insert body, it is possible to use the first corner portion for a total of six times for cutting. Become.

Further, the side surface of the insert body is formed so as to extend in parallel to the insert center line, and if it is a negative type cutting insert, the edge angle of the corner blade, the main cutting edge, and the auxiliary cutting edge is ensured and the cutting edge is secured. Strength can be improved.

Furthermore, when the insert body is formed in a rotationally symmetric shape by 120 ° around the insert centerline as described above, and is formed in a hexagonal plate shape that is symmetrical with respect to the first and second polygonal surfaces. The main cutting edge and the auxiliary cutting edge extend toward opposite polygonal surfaces as they are separated from the corner cutting edge, and the main cutting edge and the auxiliary cutting edge adjacent to each other in the circumferential direction are the second cutting edge. It is formed so as to be connected at the corner portion, and the corner blade is formed at the first corner portion from the position where the main cutting edge and the auxiliary cutting edge are most recessed in the insert center line direction at the second corner portion. In the insert of the corner blades of the first and second polygonal surfaces in the first corner portion, the amount of step height h in the insert centerline direction to the position protruding most in the insert centerline direction. By setting h / H> 0.21 with respect to the total cutting edge height H, which is the distance between the most projecting positions in the line direction in the insert center line direction, the first and second polygonal surfaces 1. A large step difference between the first and second corner portions can be ensured, and the chips extending like a string can be more easily discharged from the second corner portion.

Further, when the insert main body has an insert center line passing through the centers of the first and second polygonal surfaces, the auxiliary cutting edge is directed in a direction away from the corner edge. In order, a straight-lined Saray blade that touches the corner blade or a convex curve-shaped Saray blade that is convex in the insert centerline direction, and a secondary cutting edge convex that draws a convex curve that touches the Saray blade and protrudes in the insert centerline direction A curved portion and a secondary cutting edge concave curved portion that draws a concave curve in contact with the secondary cutting edge convex curved portion and that is concave in the insert center line direction may be provided. The machining bottom surface of the work material can be finished smoothly by the above-mentioned salai blade of the secondary cutting edge located on the tip side of the tool body, and in particular the ramping by the concave curved portion of the secondary cutting edge that is concave in the insert center line direction It is possible to secure the escape amount of the secondary cutting edge with respect to the processing bottom surface during processing.

Further, the secondary cutting edge is further arranged in order in a direction away from the corner blade, in order, a linear secondary cutting edge linear portion that contacts the secondary cutting edge concave curved portion, and the secondary cutting blade linear portion. You may provide the connection part which draws the concave curve which touches and is concave in the said insert centerline direction, and is connected to the said adjacent main cutting blade.

Furthermore, the secondary cutting edge has a secondary relief surface on the side surface of the insert body that intersects the secondary rake surface, and when viewed from a direction perpendicular to the secondary relief surface, the corner blade and the A straight line connecting the contact point with the Saray blade and the position where the auxiliary cutting edge is most recessed in the insert center line direction forms an angle larger than 14 ° with respect to a plane perpendicular to the insert center line direction. Also, it is possible to secure the escape amount of the secondary cutting edge with respect to the processing bottom surface during the ramping process.

Further, when the secondary cutting edge has a secondary flank on the side surface of the insert body intersecting with the secondary rake face in this way, the secondary flank is arranged around the first polygonal surface. By providing a plurality of sub-flank surfaces that bend so as to intersect an obtuse angle in the direction, the sub-cutting blade is the first of the plurality of sub-flank surfaces that is closest to the first corner portion side. It is formed at the crossing ridge line part of the auxiliary flank part and the auxiliary rake face, and the auxiliary flank part on the second corner part side of the first auxiliary flank part is obtuse with respect to the machining surface formed by the auxiliary cutting edge. It will be bent and retreat. For this reason, it is possible to suppress an increase in cutting resistance due to an increase in the back component force by reducing the wear width of the auxiliary flank.

However, in such a case, the second auxiliary flank face portion of the plurality of auxiliary flank face portions that intersects the first auxiliary flank face portion with the first auxiliary flank portion closest to the first corner portion. If the angle formed with respect to the extended surface toward the first corner portion is too small, the above effect may not be obtained. On the other hand, if the angle is too large, for example, as described above, the insert body May be difficult to form in a hexagonal plate shape that is symmetrical with respect to the first and second polygonal surfaces. For this reason, it is desirable that the angle is in the range of 0.5 ° to 2.5 °.

As described above, according to the present invention, it is possible to control string-wound chips so that the inside of the main rake face is discharged from the second corner portion along the main rake face. Prevents chips from colliding with the corner of 1 and prevents the insert body from being damaged, thereby extending the insert life. Also, it is necessary to replace the clamp screw early by scraping the head and wearing it. It is also possible to prevent chips from rubbing on the processed wall surface of the work material and damaging the processed surface roughness.

It is a perspective view which shows 1st Embodiment of the cutting insert of this invention. (A) The perspective view which looked at the embodiment shown in FIG. 1 from another angle, (b) It is the enlarged view of the A section in FIG. It is the top view which looked at embodiment shown in FIG. 1 from the insert centerline direction. (A) It is a side view of the arrow X direction view in FIG. 3, (b) It is an enlarged view of A part in FIG. (A). (A) Side view of arrow Y direction view in FIG. 3, (b) Enlarged view of portion A in FIG. (A). 4A is a partial sectional view of aa in FIG. 3, and FIG. 4B is an enlarged view of a portion A in FIG. It is bb partial sectional drawing in FIG. It is cc partial sectional drawing in FIG. FIG. 4 is a dd partial cross-sectional view in FIG. 3. It is ee partial sectional drawing in FIG. It is ff partial sectional drawing in FIG. It is gg partial sectional drawing in FIG. It is hh partial sectional drawing in FIG. It is ii partial sectional drawing in FIG. It is the perspective view seen from the axial direction front end side which shows one Embodiment of the blade-tip-exchange-type cutting tool of this invention which attached the cutting insert of 1st Embodiment. FIG. 16 is a side view of the embodiment shown in FIG. 15. FIG. 16 is an enlarged side view showing one cutting insert attached to the embodiment shown in FIG. 15. It is the bottom view which looked at embodiment shown in FIG. 15 from the axial direction front end side. FIG. 16 is an enlarged perspective view showing one cutting insert attached to the embodiment shown in FIG. 15. It is the perspective view seen from the axial direction front end side which shows the tool main body of embodiment shown in FIG. 15 in the state which removed the cutting insert. It is a perspective view which shows one insert mounting seat of the tool main body shown in FIG. (A) The top view seen from the insert center line direction which shows the state by which chip | tips are produced | generated by embodiment shown in FIG. 1, (b) It is a perspective view. It is a perspective view which shows 2nd Embodiment of the cutting insert of this invention. It is the top view which looked at embodiment shown in FIG. 23 from the insert centerline direction. It is a side view of the arrow W direction view in FIG. It is a side view of the arrow X direction view in FIG. It is a side view of the arrow line Y direction view in FIG. It is ZZ sectional drawing in FIG. It is an enlarged view of the 1st corner part in FIG.

FIGS. 1 to 14 show a first embodiment of the cutting insert of the present invention, FIGS. 15 to 21 show an embodiment of the cutting edge-exchangeable cutting tool of the present invention, and FIG. The state by which the chip | tip is produced | generated by the cutting insert of the said embodiment is shown. The cutting insert of the present embodiment has an insert body 1 formed of a hard material such as cemented carbide in the form of an eccentric hexagonal plate, and has two hexagonal surfaces (first and second polygons) facing each other. Surface) 2 and side surfaces 3 arranged around these hexagonal surfaces 2.

In the center of the two hexagonal surfaces 2, a mounting hole 4 having a circular cross section passing through the insert body 1 is opened, and the insert body 1 is 120 ° around the insert center line C passing through the center of the mounting hole 4. Each has a rotationally symmetric shape, and is a reversely symmetric shape with respect to the two hexagonal surfaces 2. In addition, the periphery of the opening in the hexagonal surface 2 of the mounting hole 4 is a plane portion 2a perpendicular to the annular insert center line C. Further, the lengths of the sides of the hexagonal surface 2 when viewed from the direction of the insert center line C are substantially equal.

Each of the six corner portions of the two hexagonal surfaces 2 is alternately formed as a first corner portion C1 and a second corner portion C2 in the circumferential direction of the hexagonal surface 2, and in the first corner portion C1 The included angle of the two side ridges of the intersecting hexagonal surface 2 is smaller than the included angle of the two side ridges of the hexagonal surface 2 intersecting at the second corner portion C2, and is therefore smaller than 120 °. It is set to approximately 90 °. In addition, in the two hexagonal surfaces 2, the first corner portion C1 of the other hexagonal surface 2 is located on the opposite side of the first corner portion C1 in the direction of the insert center line C1 in one hexagonal surface, The second corner portion C2 of the other hexagonal surface 2 is located on the opposite side of the second corner portion C2 of the hexagonal surface 2 in the direction of the insert center line C.

In the first corner portion C1, a corner blade 5 having a corner rake face 5a on each hexagonal face 2 and having a convex curve shape such as a convex arc when viewed from the direction of the insert center line C is formed. Further, from the corner blade 5 to the second corner portion C2 adjacent to one side (counterclockwise direction side in FIG. 3) of the first corner portion C1 in the circumferential direction of the hexagonal surface 2, the corner rake surface The main cutting edge 6 which has the main rake face 6a which continues to 5a in each hexagonal surface 2 is formed, and the other side opposite to the side where the main cutting edge 6 extends in the circumferential direction of the hexagonal surface 2 from the corner blade 5 ( On the hexagonal surface 2, auxiliary cutting edges 7 are formed on the hexagonal surfaces 2, which are also connected to the corner rake surfaces 5 a.

Therefore, in the cutting insert of the present embodiment in which the insert body 1 has a two-sided symmetric shape with respect to the two hexagonal surfaces 2, the corner blade 5 to the main cutting edge 6 and the sub-cutting edge between these two hexagonal surfaces 2. 7 extends in the opposite direction to the circumferential direction of the insert body 1. That is, for one side surface 3, the main cutting edge 6 is formed at the intersection ridge line portion with one hexagonal surface 2, and the sub cutting edge 7 is formed at the intersection ridge line portion with the other hexagonal surface 2. .

Further, the side surface 3 is parallel to the insert center line C, and the intersecting ridge line portion between the side surfaces 3 adjacent to each other in the circumferential direction in the first corner portion C1 is formed in a convex curved surface, and the corner relief surface of the corner blade 5 In addition, the portion between the first and second corner portions C1 and C2 is formed in a flat shape, and the main flank of the main cutting edge 6 and the auxiliary flank of the sub cutting edge 7 on the front and back hexagonal surfaces 2 are formed. It is said. That is, the cutting insert of this embodiment is a negative type cutting insert.

The main cutting edge 6 has a convex curve shape that is convex in the direction of the insert center C line, or a straight line, or a shape in which the convex curve and the straight line are smoothly continuous when viewed from the direction facing the side surface 3 that is the flank. As the distance from the corner blade 5 increases, the second hexagonal surface 2 is inclined so as to recede to the second corner portion C2.

On the other hand, the secondary cutting edge 7 is arranged in the direction of the straight line or the insert center line C in contact with the corner blade 5 in order toward the direction away from the corner blade 5 when viewed from the direction facing the side surface 3 which is also the flank. A convex curved Saray blade 7A that is convex, a secondary cutting edge convex curved portion 7B that draws a convex curve that is in contact with the Saray blade 7A in the direction of the insert center line C, and this secondary cutting edge convex curved portion 7C, and a secondary cutting edge concave curve portion 7C that draws a concave curve that is in contact with 7B and that is concave in the direction of the insert center line C.

Further, the secondary cutting edge 7 includes a linear secondary cutting edge linear portion 7D that is in contact with the secondary cutting edge concave curved portion 7C, and a concave portion in the direction of the insert center line C that is in contact with the secondary cutting blade linear portion 7D. The connecting part 7E connected to the adjacent main cutting edge 6 in the 2nd corner part C2 is provided, drawing the concave curve which becomes. Accordingly, the bottom of the concave curve formed by the connecting portion 7E is a position P that is most concave in the direction of the insert center line C in the auxiliary cutting edge 7 of the hexagonal surface 2 in this embodiment.

The corner blade 5 has a concave curve that is recessed toward the opposite hexagonal surface 2 in the direction of the insert center line C toward the main cutting edge 6 on the main cutting edge 6 side. A corner blade concave curved portion 5A extending toward the second side is formed. As with the corner blade concave curve portion 5A of the main cutting edge 6, the opposite hexagonal surface 2 is drawn while forming a concave curve recessed on the opposite hexagonal surface 2 side. The concave curved portion extending toward the side may be formed so as to be smoothly continuous with the corner blade concave curved portion 5A.

Further, on the side of the secondary cutting edge 7 of the corner blade 5, a corner projecting in the direction of the insert center line C while drawing a convex curve which is smoothly continuous with the concave curved portion 5A of the corner blade and convex in the direction of the insert center line C. A blade convex curve portion 5B is formed, and the corner blade convex curve portion 5B is smoothly continuous so as to be in contact with the salai blade 7A of the sub-cutting blade 7. The corner blade 5 and the salai blade 7A Is the position Q that protrudes most in the direction of the insert center line C on the hexagonal surface 2. Note that the boundary (contact point) between the corner blade concave curve portion 5A and the corner blade convex curve portion 5B is located, for example, on the bisector of the first corner portion C1.

Here, in the present embodiment, the main cutting edge 6 and the auxiliary cutting edge 7 are most recessed in the direction of the insert center line C in the second corner portion C2 (in this embodiment, the bottom of the connecting portion 7E of the auxiliary cutting edge 7). ) The distance in the insert center line C direction from P to the position Q at which the corner blade 5 protrudes most in the direction of the insert center line C in the first corner portion C1 (in this embodiment, a contact point with the Sarai blade 7A) The amount h and the interval in the insert center line C direction between the positions Q protruding most in the insert center line C direction of the corner blades 5 of the both hexagonal surfaces 2 in the first corner portion C1 is defined as the total cutting edge height H. H / H> 0.21. In this embodiment, h / H = 0.28.

Further, in the present embodiment, when viewed from the direction perpendicular to the side surface 3 that is the sub-flank, the contact point with the Saray blade 7A, which is the position Q where the corner blade 5 protrudes most in the insert center line C direction, The straight line L connecting the sub-cutting blade 7 with the most recessed position P in the insert center line C direction is set to form an angle θ larger than 14 ° with respect to a plane perpendicular to the insert center line C direction. Yes.

The corner rake face 5a, the main rake face 6a, and the auxiliary rake face 7a have lands on the corner blade 5, the main cutting edge 6 and the auxiliary cutting edge 7, respectively. As the secondary cutting edge 7 is directed to the inside of the hexagonal surface 2, the second direction toward the opposite hexagonal surface 2 side in the direction of the insert centerline C with a substantially constant inclination with respect to the plane perpendicular to the insert centerline C. The first rake face has a second rake face that faces the opposite hexagonal face 2 side at a larger inclination angle with respect to a plane perpendicular to the insert center line C than the first rake face. However, the minor rake face 7a is convex on the opposite side to the opposite hexagonal face 2 in the direction along the minor cutting edge 7, as shown in FIG. A convex curved surface portion 7b is formed inside the corner blade concave curved portion 5A of the corner blade 5 to which the auxiliary cutting blade 7 is continuous.

Such a cutting insert is attachable to and detachable from the insert mounting seat 12 formed on the outer periphery of the tip end of the tool body 11 rotated in the tool rotation direction T around the axis O as shown in FIGS. And a set of corner blades 5, a main cutting edge 6, and a sub cutting edge 7 are used for cutting. In the present embodiment, the tool body 11 is formed in a substantially disk shape with the axis O as the center, and a tip pocket 14 extending toward the rear end is formed on the outer periphery of the tip, and the insert mounting seat 12 is The tip pocket 14 is formed in the wall surface facing the tool rotation direction T as a recess that opens to the wall surface and the tip and outer peripheral surfaces of the tool body 11. In the present embodiment, a plurality (seven) of chip pockets 14 and insert mounting seats 12 are formed at equal intervals in the circumferential direction.

As shown in FIGS. 20 and 21, the insert mounting seat 12 has an annular flat bottom surface 12 a facing the tool rotation direction T, and an outer periphery of the tip of the tool body 11 that rises perpendicularly to the bottom surface 12 a on the tool rotation direction T side. And a wall surface 12c facing the inner peripheral side of the tip. The bottom surface 12a is inclined slightly toward the tool rotation direction T as it goes toward the rear end side of the tool body 11, and a screw hole 12d into which the clamp screw 13 is screwed is formed at the center. Further, relief portions that prevent interference with the insert body 1 are formed between the bottom surface 12a and the wall surfaces 12b and 12c, and at the intersection ridge line portion between the tip surface and the outer peripheral surface of the tool body 11 and the bottom surface 12a.

In such an insert mounting seat 12, the cutting insert of the above embodiment has one hexagonal surface 2 of the insert body 1 directed in the tool rotation direction T, and one corner blade 5 of the one hexagonal surface 2 is placed. While projecting to the outer peripheral side of the front end of the tool body 11, the main cutting edge 6 connected to the corner blade 5 is directed toward the outer peripheral side of the tool body 11 so as to extend to the side opposite to the tool rotation direction T. Further, the sub-cutting blade 7 connected to the corner blade 5 is seated so as to face the rear end side slightly toward the inner peripheral side toward the tip end side of the tool body 11. At this time, the Sarai blade 7A of the sub-cutting blade 7 is substantially positioned on a plane perpendicular to the axis O of the tool body 11, and the insert center line C is moved to the opposite side of the tool rotation direction T and the rear of the tool body 11 is moved. It is arranged slightly inclined so as to go to the end side.

Further, the hexagonal surface 2 opposite to the one hexagonal surface 2 of the insert main body 1 is such that the flat portion 2a at the center thereof is in close contact with the bottom surface 12a of the insert mounting seat 12, and further the tip end side of the tool main body 11 The two side surfaces 3 of the insert main body 1 connected to the remaining two secondary cutting edges 7 in the one hexagonal surface 2 other than the secondary cutting edge 7 projected in the contact with the wall surfaces 12b and 12c of the insert mounting seat 12 Be made. In addition, the wall surface between these wall surfaces 12b and 12c does not contact the insert main body 1 seated in this way, and a slight space is provided between the opposing side surfaces 3. Then, when the clamp screw 13 inserted through the mounting hole 4 is screwed into the screw hole 12d, the insert main body 1 is pressed against the bottom surface 12a and the two side surfaces 3 are pressed against the wall surfaces 12b and 12c. And fixed to the insert mounting seat 12 and attached to the tool body 11.

In the cutting insert having the above-described configuration that is attached to the tool body 11 in this manner, the main cutting edge 6 side portion of the corner blade 5 that is projected to the outer periphery side of the tool body 11 is directed to the outer periphery side of the tool body 11. A corner blade concave curve portion 5A extending toward the opposite hexagonal surface 2 while drawing a concave curve concaved on the side of the hexagonal surface 2 opposite to the hexagonal surface 2 on which the main cutting edge 6 is formed. Is formed. Accordingly, the chips generated by the corner blade 5 and the main cutting edge 6 are generated by the corner blade concave curved portion 5A at the tip side portion of the tool body 11 regardless of the depth of cut.

Here, the chip generated by such a concave curved corner blade concave curved portion 5A is bent in a concave curved shape in the same manner in a cross section whose tip side portion is orthogonal to the generation direction, and stress In response to this, as shown in FIG. Then, the chips curled in this manner extend in the form of a coil winding from the inner side of the main rake face 6a along the main rake face 6a toward the rear end side of the tool body 11, that is, the second corner part C2. 2 is controlled so as to be discharged from the second corner portion C2 bent at an obtuse angle as viewed from the direction opposite to 2.

For this reason, the chip | tip produced | generated by the corner blade 5 which protruded to the front-end | tip outer peripheral part of the tool main body 11, and the main cutting blade 6 connected to this is the other 1st corner of the hexagonal surface 2 in which the tool rotation direction T was orientated. It can avoid colliding with the unused corner blade 5 etc. in the part C1, and it can prevent that a defect | deletion arises in the periphery of the unused corner blade 5 by the collision of such a chip. Moreover, since the chip flows out along the main rake face 6a inside the main rake face 6a as described above, the work material formed by the clamp screw 13 for fixing the insert body, the corner blade 5 and the main cutting edge 6 is used. The processing wall surface is not rubbed, the head wear of the clamp screw 13 does not require early replacement, and the processing surface roughness is not impaired.

In this embodiment, the auxiliary rake face 7a of the auxiliary cutting edge 7 connected to the corner edge 5 is convex in the direction of the insert center line C in the direction along the auxiliary cutting edge 7, that is, the opposite hexagonal shape. A convex curved surface portion 7b that is convex on the side opposite to the surface 2 is formed inside the corner blade concave curved portion 5A, and the chips curled with a small radius as described above are formed on the convex curved surface portion 7b. The corner blades are in sliding contact with the concave curved portion 5A side. Therefore, even if the chip receives resistance by sliding contact with the convex curved surface portion 7b, the discharge is controlled so as to be curled to a smaller radius and extend in a string shape, so that the insert body 1 is more reliably connected. Defects, wear of the clamp screw 13 and deterioration of the machined surface roughness can be prevented.

Furthermore, the insert main body 1 of the present embodiment has a rotationally symmetric shape by 120 ° around the insert center line C passing through the centers of the two hexagonal surfaces, and the six hexagonal surfaces 2 have a reverse-inverted symmetrical shape. It is formed in the shape of a square plate, and the hexagonal surface 2 has three first and second corner portions C1 and C2 arranged alternately in the circumferential direction and opposite to each other in the direction of the insert center line C. In these two hexagonal surfaces 2, the main cutting edge 6 and the auxiliary cutting edge 7 are formed so as to extend from the corner blade 5 in opposite directions in the circumferential direction of the insert body 1. For this reason, it becomes possible to use three sets of the corner blades 5, the main cutting blade 6, and the auxiliary cutting blade 7 of the hexagonal surface 2 on the front and back with one insert body 1, which is efficient and economical. .

Furthermore, the cutting insert of the present embodiment is a negative type cutting in which the side surface 3 of the insert body 1 serving as a flank surface of the corner blade 5, the main cutting blade 6 and the auxiliary cutting blade 7 extends in parallel to the insert center line C. It is an insert. For this reason, the cutting edge angle | corner of the corner blade 5, the main cutting blade 6, and the subcutting blade 7 is ensured comparatively large, and edge strength is improved, and also the defect | deletion of the insert main body 1 can be prevented.

On the other hand, in this embodiment, the main cutting edge 6 and the auxiliary cutting edge 7 extend toward the opposite hexagonal surface 2 as they are separated from the corner cutting edge 5, and the main cutting edge 6 and the auxiliary cutting edge that are adjacent to each other in the circumferential direction. The cutting edge 7 is connected to the connecting portion 7E at the second corner portion C2, and the connecting portion 7E at the second corner portion is recessed most in the direction of the insert center line C at the main cutting edge 6 and the auxiliary cutting edge 7. The position P is formed. For this reason, as described above, chips extending along the main rake face 6a on the inner side of the main rake face 6a can be more easily discharged from the second corner portion C2 which is the most recessed position P.

Further, in the present embodiment, the corner blade 5 is formed in the first corner portion C1 from the position P where the main cutting edge 6 and the sub-cutting blade 7 are most recessed in the insert center line C direction in the second corner portion C2. The edge step height h in the insert center line C direction up to the position Q that protrudes most in the insert center line C direction is the largest in the insert center line C direction of the corner blades 5 of the two hexagonal surfaces 2 in the first corner portion C1. With respect to the total cutting edge height H, which is the distance between the protruding positions Q in the insert center line C direction, h / H> 0.21.

That is, the above-mentioned cutting edge level difference h, which is the height of the corner blade 5 on each hexagonal surface 2, has a large proportion of the total cutting edge height H, which is the thickness of the insert body 1. Since the height to the terminal end of 6 is large, the insert body 1 is inclined so that the insert center line C is slightly inclined toward the rear end side of the tool body 11 as it goes to the side opposite to the tool rotation direction T as described above. Even if it is attached to the insert mounting seat 12, the main cutting edge 6 extends to the side opposite to the tool rotation direction T as it goes to the rear end side of the tool body 11, and the axial rake angle is a positive angle. It is possible to control so that chips are reliably discharged from the second corner portion C2.

Further, by setting the cutting edge level difference h to a relatively large ratio of h / H> 0.21 with respect to the total cutting edge height H, the corners of the auxiliary cutting edge 7 directed toward the tip side of the tool body 11 are reduced. The amount of depression from the blade 5 to the most depressed position P of the connecting portion 7E increases. For this reason, if the clearance angle of the side surface 3 serving as the flank face of the auxiliary cutting edge 7 is the same, the escape amount of the auxiliary cutting edge 7 can be secured larger than that of a cutting insert having a small h / H. Even in the ramping process in which the main body 11 is sent to the oblique tip side with respect to the axis O and the plunge process in which the main body 11 is sent in the direction of the axis O, it is possible to avoid the portion on the second corner portion C2 side of the auxiliary cutting edge 7 from interfering with the machining bottom surface. .

Note that these effects are obtained when the corner blade 5 protrudes most in the insert center line C direction and the sub-cutting blade 7 is most recessed in the insert center line C direction when viewed from the direction perpendicular to the side surface 3. The straight line L connecting the position P can also be obtained by setting an angle θ larger than 14 ° with respect to a plane perpendicular to the insert center line C direction. Here, if the cutting edge level difference h is h / H ≦ 0.21 with respect to the total cutting edge height H, or the angle θ is less than 14 °, these effects may not be obtained.

In order to achieve such an effect more reliably, it is desirable that the cutting edge level difference h is h / H> 0.23 with respect to the total cutting edge height H, and h / H> 0.25. Is more desirable. However, if h / H becomes too large, the thickness of the insert body 1 between the two hexagonal surfaces 2 becomes too thin, and the insert body 1 is liable to be lost due to insufficient strength, so h / H ≦ 0.33. It is desirable that

Furthermore, in the present embodiment, the auxiliary cutting edge 7 is provided with a salai blade 7A having a linear shape in contact with the corner blade 5 or a convex curve shape convex in the direction of the insert center line C, and the tool body 11 is attached to the axis O. In the case of normal milling that feeds in a direction perpendicular to the surface, the bottom surface of the machining can be finished smoothly by the Saray blade 7A. Further, on the side opposite to the corner blade 5 of the Saray blade 7A, a convex curved portion 7B having a convex curve that is convex in the direction of the insert center line C is continuous, and the ramping process and the plunging process are performed. In this case, cutting can be performed using the sub cutting edge convex curved portion 7B.

Further, on the side opposite to the corner blade 5 of the sub cutting edge convex curve portion 7B, a sub cutting edge concave drawing a concave curve in contact with the sub cutting blade convex curve portion 7B and concave in the insert center line C direction. A curved portion 7C is formed, and the secondary cutting edge concave curved portion 7C has a secondary cutting edge as viewed from the direction perpendicular to the side surface 3 as compared with the Sarai blade 7A and the secondary cutting edge convex curved portion 7B. When 7 goes to the 2nd corner part C2 side, the ratio dented in the insert centerline C direction becomes large. For this reason, the escape amount of the portion of the secondary cutting edge 7 on the second corner portion C2 side can be ensured more, and interference with the processing bottom surface during ramping processing and plunge processing can be more reliably prevented. .

In the present embodiment, the secondary cutting edge 7 is further in contact with the secondary cutting edge concave curve portion 7C, and the linear secondary cutting edge linear portion 7D is in contact with the secondary cutting edge linear portion 7D. And a connecting portion 7E connected to the adjacent main cutting edge 6 while drawing a concave curve that is concave in the direction of the line O, and connected to the sub cutting edge concave curved portion 7C by the sub cutting edge linear portion 7D. The cutting edge strength of the auxiliary cutting edge 7 between the part 7E is ensured. However, the portion of the secondary cutting edge linear portion 7D may be a concave curved shape in which the secondary cutting edge concave curved portion 7C and the connecting portion 7E are extended and continuous. In the present embodiment, the case where the present invention is applied to a negative type cutting insert in which the side surface 3 of the insert body 1 is parallel to the insert center line C as described above is described. However, the present invention is applied to a positive type cutting insert. Is also possible.

Next, FIG. 23 to FIG. 29 show a second embodiment of the cutting insert of the present invention, and the same reference numerals are assigned to the parts common to the first embodiment shown in FIG. 1 to FIG. Therefore, the description is omitted. In the cutting insert of the second embodiment, the auxiliary cutting edge 7 has an auxiliary flank on the side surface 3 of the insert body 1 intersecting the auxiliary rake face 7a as in the first embodiment. In the first embodiment, the side surface 3 of the insert body 1 that is the secondary flank is formed in a flat shape between the first and second corner portions C1 and C2, whereas the side flank is the secondary flank. The side surface 3 is provided with a plurality of (two) sub-flank portions 3a and 3b that bend so as to intersect an obtuse angle in the circumferential direction of the hexagonal surface 2 that is the first polygonal surface. Features.

That is, in the second embodiment, the side surface 3 serving as a secondary flank has a narrow circumferential width in order from the first corner portion C1 side of the hexagonal surface 2 on which the secondary cutting edge 7 is formed. A planar first sub-flank 3a and a flat second sub-flank 3b having a circumferential width wider than that of the first sub-flank 3a are formed. The two auxiliary flank portions 3a and 3b intersect at an obtuse angle in the circumferential direction. As shown in FIG. 29, the first corner portion of the second sub-flank surface portion 3b where the first sub-flank portion 3a of the first corner portion C1 intersects the first sub-flank surface portion 3a. The angle α formed with respect to the extended surface S toward the C1 side is in the range of 0.5 ° to 2.5 ° in this embodiment, and is particularly 1.5 °.

In such a cutting insert of the second embodiment, the intersecting ridge line portion between the second sub-flank surface portion 3b and the sub-rake surface 7a is the intersecting ridge line portion between the first sub-flank surface portion 3a and the sub-rake surface 7a. With respect to the extension line toward the second corner portion C <b> 2, the line moves backward so as to gradually move away from the corner blade 5. For this reason, the auxiliary cutting edge 7 formed at the intersecting ridge line portion between the first auxiliary flank face portion 3a and the auxiliary rake face 7a is used as the above-mentioned salai blade 7A on a plane perpendicular to the axis O of the tool body 11 as described above. When approximately positioned, the intersecting ridge line portion of the second auxiliary flank surface portion 3b and the auxiliary rake surface 7a is bent at an obtuse angle with respect to the plane perpendicular to the axis O, that is, the machining surface of the work material by the salai blade 7A. 2 toward the rear end side in the direction of the axis O as it goes toward the corner C2.

Therefore, according to the cutting insert of this 2nd Embodiment, the Saray blade formed in the cross ridgeline part of the 1st minor relief surface part 3a and the minor rake face 7a with a narrow width | variety wears the minor cutting edge 7 by cutting. 7A portion can be suppressed, the wear width can be prevented from increasing, the increase in the back force due to the increase in the wear width is suppressed, the increase in cutting resistance is suppressed, and stable cutting is performed. It becomes possible. And if the crossing angle of the 2nd wide flank 2b which adjoins via the 2nd corner part C2 is made equal to 1st Embodiment, the blade edge | tip to which the cutting insert of this 1st Embodiment is attached It is possible to attach the cutting insert of the second embodiment as it is to the insert mounting seat 12 formed in the tool body 11 of the exchangeable cutting tool.

In the cutting insert according to the second embodiment, the first sub-flank portion 3a closest to the first corner portion C1 among the plurality of sub-flank portions 3a, 3b is the first sub-flank portion. If the angle α formed with respect to the extended surface S of the second sub-flank surface portion 3b intersecting the surface portion 3a toward the first corner portion C1 is too small, the first and second sub-flank surface portions 3a and 3b are There is a possibility that the wear width cannot be reduced due to being close to one plane, and the above-described effect cannot be obtained. On the other hand, if the angle α is too large, it becomes difficult to form the insert body into a hexagonal plate shape that is symmetric with respect to the first and second polygonal surfaces 2 as in the present embodiment, for example. Therefore, it is desirable that the angle α be in the range of 0.5 ° to 2.5 °.

As described above, according to the cutting insert and the cutting edge-exchangeable cutting tool of the present invention, the control is performed so that the chord wound chips are discharged from the second corner portion along the main rake face inside the main rake face. It is possible to prevent the chip from colliding with the unused first corner and to prevent the insert body from being damaged, thereby prolonging the insert life. It is also possible to prevent the screw from being replaced at an early stage or the surface roughness of the machined surface from being damaged due to chips scraping on the machined wall of the work material. Therefore, industrial use is possible.

1 Insert body 2 Hexagonal surface (first and second polygonal surfaces)
3 side face 3a first auxiliary flank face part 3b second auxiliary flank face part 4 mounting hole 5 corner blade 5a corner rake face 5A corner blade concave curve part 5B corner blade convex curve part 6 main cutting edge 6a main rake face 7 auxiliary Cutting edge 7a Secondary rake face 7b Convex curved surface part 7A Saray blade 7B Secondary cutting edge convex curved part 7C Secondary cutting edge concave curved part 7D Secondary cutting edge linear part 7D
7E Connecting portion 11 Tool body 12 Insert mounting seat 13 Clamp screw C Insert center line C1 First corner portion C2 Second corner portion P In the second corner portion C2, the main cutting edge 6 and the auxiliary cutting edge 7 are the insert centerline. The most recessed position in the C direction Q The position in which the corner blade 5 protrudes the most in the direction of the insert center line C in the first corner portion C1 h Cutting edge step height H Total cutting edge height L A straight line connecting the contact point (position Q) and the position P between the corner blade 5 and the salai blade 7A, as viewed from the direction in which the second sub-flank portion 3b extends to the first corner portion C1 side θ side surface 3, an angle formed by the straight line L with respect to a plane perpendicular to the direction of the insert center line C, as viewed from the direction perpendicular to 3 (sub-flank), the first sub-flank 3 a is To the first corner C1 side Axis T tool rotation direction of the angle O tool body 11 makes with the long surface S

Claims (11)

A polygonal plate-like insert body having first and second polygonal surfaces facing each other and side surfaces disposed around the first and second polygonal surfaces;
Of the corner portion of the first polygonal surface, a corner blade having a corner rake surface on the first polygonal surface is formed in the first corner portion,
From the corner blade to the second corner portion adjacent to the first corner portion in the circumferential direction of the first polygonal surface, the main rake surface connected to the corner rake surface becomes the first polygonal surface. A main cutting edge is formed,
On the opposite side of the circumferential direction of the first polygonal surface from the corner blade to the side on which the main cutting edge extends, the minor cutting surface having a minor rake surface connected to the corner rake surface on the first polygonal surface. The blade is formed,
A corner blade extending toward the second polygonal surface while drawing a concave curve recessed toward the second polygonal surface toward the main cutting blade at a portion on the main cutting blade side of the corner blade A cutting insert in which a concave curved portion is formed. A convex curved surface portion that is convex on the opposite side of the second polygonal surface in the direction along the auxiliary cutting edge is formed on the inner side of the concave curved portion of the corner blade. The cutting insert according to claim 1. The insert body has a rotationally symmetric shape by 120 ° around an insert center line passing through the centers of the first and second polygonal surfaces, and has a reverse-inverted symmetrical shape with respect to the first and second polygonal surfaces. It is formed in a hexagonal plate shape,
Each of the first and second polygonal surfaces has three first and second corner portions arranged alternately in the circumferential direction and opposite to each other in the insert centerline direction. ,
The said 1st, 2nd polygon surface WHEREIN: The said main cutting edge and the subcutting blade are extended in the opposite direction to the circumferential direction of the said insert main body from the said corner blade. 2. The cutting insert according to 2. The cutting insert according to claim 3, wherein a side surface of the insert body extends parallel to the insert center line. The main cutting edge and the auxiliary cutting edge extend toward opposite polygonal surfaces as they are separated from the corner cutting edge, and the main cutting edge and the auxiliary cutting edge adjacent to each other in the circumferential direction are the second corner cutting edge. Connected at the
From the position where the main cutting edge and the auxiliary cutting edge are most recessed in the insert center line direction in the second corner portion, to the position where the corner blade protrudes most in the insert center line direction in the first corner portion. The cutting edge level difference h in the insert center line direction is
With respect to the total cutting edge height H, which is the distance in the insert center line direction between the positions of the first and second polygonal surface corner blades that protrude most in the insert center line direction in the first corner portion. ,
The cutting insert according to claim 3 or 4, wherein h / H> 0.21. The insert body has an insert center line passing through the centers of the first and second polygonal surfaces, and the sub-cutting blades are sequentially connected to the corner blades in a direction away from the corner blades. A linear curve that touches or a convex curved Saray blade that is convex in the direction of the insert centerline, a secondary cutting edge convex curve that draws a convex curve that touches the Saray blade and is convex in the direction of the insert centerline, and The sub cutting edge concave curve-shaped part which draws the concave curve which touches a sub cutting-blade convex curve-shaped part and becomes concave in the said insert centerline direction is provided, The any one of Claims 1-5 characterized by the above-mentioned. The cutting insert according to claim 1. The secondary cutting edge is further in contact with the secondary cutting edge linear portion and the linear secondary cutting edge linear portion in contact with the secondary cutting edge concave curved portion in order in a direction away from the corner blade. The cutting insert according to claim 6, further comprising a connecting portion connected to the adjacent main cutting edge by drawing a concave curve that is concave in the insert center line direction. The sub-cutting blade has a sub-flank on the side surface of the insert body that intersects the sub-rake face, and the corner blade, the salai blade, and the like when viewed from the direction perpendicular to the sub-flank. The straight line connecting the contact point and the position where the auxiliary cutting edge is most recessed in the insert center line direction forms an angle greater than 14 ° with respect to a plane perpendicular to the insert center line direction. The cutting insert according to claim 6 or claim 7, characterized by the above. The secondary cutting edge has a secondary flank on the side surface of the insert body that intersects the secondary rake surface, and the secondary flank intersects an obtuse angle toward the circumferential direction of the first polygonal surface. The cutting insert according to any one of claims 1 to 8, further comprising a plurality of sub-flank portions that bend so as to. Of the plurality of sub-flank parts, the first sub-flank part closest to the first corner part is on the first corner part side of the second sub-flank part intersecting with the first sub-flank part 10. The cutting insert according to claim 9, wherein an angle formed with respect to the extended surface is within a range of 0.5 ° to 2.5 °. The cutting insert according to any one of claims 1 to 10, wherein the insert insert is formed on an outer periphery of a tip end of a tool body rotated about an axis, and the corner blade is connected to the tip of the tool body. While projecting to the outer peripheral side, the main cutting blade connected to the corner blade is positioned on the outer peripheral side of the tool body, and the auxiliary cutting blade is positioned on the tip side of the tool body, and the corner blade, the main cutting blade, A cutting edge exchangeable cutting tool, wherein the corner rake face, the main rake face, and the auxiliary rake face connected to the auxiliary cutting edge are detachably attached to the tool rotating direction.

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