JP2018043321A - Cutting insert and tip replaceable cutting tool - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a cutting insert which suppresses breakage during cutting, and a tip replaceable cutting tool with use of the same.SOLUTION: In a cutting insert which is detachably attached to a tip of a tool body which rotates around a tool axis, a mounting hole which penetrates in one direction is provided, and a fixation member having a shank and a lock part positioned at one end of the shank is inserted in the mounting hole and is fixed to a tool body. The mounting hole is provided with a taper part which reduces a diameter of the mounting hole along an insertion direction of the fixation member, and the taper part has a polishing part at least a part of a portion thereof contacting the lock part of the fixation member.SELECTED DRAWING: Figure 20

Description

  The present invention relates to a cutting insert and a cutting edge exchangeable cutting tool.

  2. Description of the Related Art There is known a cutting edge exchangeable cutting tool in which a detachable cutting insert is attached to the tip of a tool body. The cutting insert is provided with a mounting hole through which a screw for fixing to the tool body is inserted. A large load acts on the shaft portion of the screw during cutting. When a screw having a sufficient shaft diameter is used to suppress the breakage of the screw, it is necessary to enlarge the mounting hole of the cutting insert. Thereby, a thin part is formed in a cutting insert, and it becomes a cause of cutting insert breakage. Patent Document 1 describes a cutting insert having an intermediate surface that is built up on a thin portion in a side surface portion.

US Patent Application Publication No. 2016/0167137

  However, for example, in a small-sized cutting insert or the like, it is difficult to build up enough to suppress breakage.

  This invention is made | formed in view of such a situation, Comprising: It aims at providing the cutting insert which suppresses the damage at the time of cutting, and the blade-tip-exchange-type cutting tool using the same.

  In order to solve the above problems, as one aspect of the present invention, a cutting insert is a cutting insert that is detachably attached to the tip of a tool body that rotates around a tool axis, and is provided with an attachment hole that penetrates in one direction. A fixing member having a shaft portion and a locking portion located at one end of the shaft portion is inserted into the mounting hole and fixed to the tool body, and the mounting hole has a mounting hole along the insertion direction of the fixing member. A taper portion for reducing the diameter of the fixing member is provided, and the taper portion has a polishing portion in at least a part of a portion in contact with the locking portion of the fixing member.

  In the cutting insert, stress accompanying fastening is applied to a portion (contact portion) that contacts the fixing member. For this reason, the cutting insert tends to cause cracks starting from fine irregularities on the surface of the contact portion. According to the above-described configuration, the cutting insert is provided with the polishing portion at least at a part of the contact portion, whereby the unevenness that becomes the starting point of the crack is removed. Thereby, it can suppress that a cutting insert breaks. Moreover, the cutting insert has a taper part in an attachment hole, and contacts the latching | locking part of a fixing member in a taper part. Thereby, relative alignment of the central axis of the mounting hole and the central axis of the fixing member is facilitated.

  Moreover, the above-mentioned cutting insert WHEREIN: The said attachment hole is good also as a structure by which a rake face is provided in the side surface which penetrates a pair of main surface and connects the peripheral edges of a pair of said main surface.

  In this case, a load is easily applied to the fixing member for fixing the cutting insert, and it is necessary to increase the diameter of the fixing member, and a thin portion is easily formed on the cutting insert. According to the above-mentioned cutting insert, since the starting point of a crack hardly arises in a contact part with a fixed member, even if it is a cutting insert in which a thin part was formed, breakage can be controlled. Moreover, since it is not necessary to form a build-up on the rake face, it is possible to prevent the chip dischargeability from being lowered due to the build-up.

  In the above-described cutting insert, the attachment hole has a small diameter portion located at an end portion on the side where the hole diameter of the taper portion is small, and the taper portion has a curved portion that smoothly connects to the small diameter portion. And it is good also as a structure which contacts the latching | locking part of the said fixing member in the said curved part.

  The above-mentioned cutting insert can adjust the attitude | position of a cutting insert easily at the time of fastening of a fixing member by contacting with the latching | locking part of a fixing member in a curved part.

  Moreover, in the above-mentioned cutting insert, it is preferable that arithmetic average roughness Ra of the said grinding | polishing part is 0.35 micrometer or less.

  According to the above-mentioned cutting insert, generation | occurrence | production of a crack is suppressed more reliably.

  Further, the above-mentioned cutting insert has a pair of main surfaces which are front and back surfaces of the cutting insert, and the attachment holes are provided through the pair of main surfaces, and the attachment holes have respective main surfaces. It is good also as a structure in which a pair of said taper part which makes a diameter small toward inner side is provided.

  The cutting insert having the above-described configuration can be attached to the tool body with the front and back reversed.

  In order to solve the above-mentioned problem, a cutting edge exchangeable cutting tool as one aspect of the present invention includes a cutting tool, a tool main body that is provided with a mounting seat provided with a threaded hole at a tip, and rotates about an axis. The screw inserted into the screw hole and fixing the cutting insert to the mounting seat.

  According to this structure, the blade-tip-exchange-type cutting tool which suppresses the damage of the cutting insert at the time of cutting can be provided.

  According to the cutting insert and the cutting edge replaceable cutting tool of the present invention, it is possible to provide a cutting insert that suppresses breakage during cutting, and a cutting edge replaceable cutting tool using the cutting insert.

It is a perspective view which shows the blade-tip-exchange-type cutting tool which concerns on 1st Embodiment. It is the front view which looked at the blade-tip-exchange-type cutting tool from the front end in the tool axis direction toward the base end side. It is the side view which looked at the blade-tip-exchange-type cutting tool from the III direction of FIG. It is the side view which looked at the blade-tip-exchange-type cutting tool from the IV direction in FIG. It is a perspective view which shows the cutting insert which concerns on 1st Embodiment. It is the figure (figure which looked at the long side in the front) which looked at the cutting insert from the insert long side axis direction. It is the figure (figure which looked at the principal surface in the front) which looked at the cutting insert from the insert principal surface axial direction. It is the figure (figure which looked at the short side in the front) which looked at the cutting insert from the insert short side axis direction. It is a figure which shows the IX-IX cross section of FIG. It is a figure which shows the XX cross section of FIG. It is a figure which shows the XI-XI cross section of FIG. It is a figure which shows the XII-XII cross section of FIG. It is a perspective view which shows a tool main body. It is the front view which looked at the tool main part toward the base end side from the front-end | tip of a tool axial direction. It is the side view which looked at the tool main body from the XV direction of FIG. It is the side view which looked at the tool main body from the XVI direction of FIG. It is a perspective view which shows the cutting insert which concerns on 2nd Embodiment. It is the figure (figure which looked at the short side in the front) which looked at the cutting insert from the insert short side axis direction. It is a figure explaining a ramping process. It is sectional drawing of the blade-tip-exchange-type tool with which the cutting insert of 3rd Embodiment was attached. It is an enlarged view of the area | region XXI of FIG.

<First Embodiment>
Hereinafter, the blade exchange type cutting tool 1 and the cutting insert 3 according to the first embodiment will be described with reference to FIGS.

[Schematic configuration of cutting edge exchangeable cutting tool]
As shown in FIGS. 1 to 4, the cutting edge-exchangeable cutting tool 1 of the present embodiment includes a tool body 2 formed of a steel material or the like, a cutting insert 3 formed of a hard material such as cemented carbide, It has. A concave insert mounting seat 4 is formed on the outer periphery of the tip of the tool body 2 that is rotated around the tool axis O. A cutting insert 3 having a cutting edge 5 is detachably mounted on the insert mounting seat 4.

  As shown in FIGS. 5 to 8, the cutting insert 3 is a so-called vertical blade double-sided cutting insert. The cutting insert 3 has a rectangular plate shape, and is formed in a reverse-symmetrical shape. The cutting insert 3 includes a pair of main surfaces 11 that are front and back surfaces, and a side surface 10 that connects the peripheral edges of the pair of main surfaces 11. The side surface 10 includes four surfaces arranged in the circumferential direction on the outer periphery of the cutting insert 3. The side surface 10 includes a pair of long side surfaces 12 that are arranged in the back direction (arranged back to back), and a pair of short side surfaces 13 that are arranged in the back direction and connect the pair of long side surfaces 12 to each other. . The long side surface 12 is connected to the long side among the four sides (a pair of long sides and a pair of short sides) forming the periphery of the rectangular main surface 11. The short side surface 13 is connected to the short side among the four sides forming the periphery of the main surface 11. Each of the long side surface 12 and the short side surface 13 is formed in a rectangular shape.

The cutting insert 3 has at least a main cutting edge 14, a secondary cutting edge 15, and a corner edge 21 as the cutting edge 5. The main cutting edge 14 is formed on the intersecting ridge line between the main surface 11 and the long side surface 12. The auxiliary cutting edge 15 is formed on the intersecting ridge line between the long side surface 12 and the short side surface 13. The corner blade 21 is located at a corner portion (corner portion) of the long side surface 12 and connects the main cutting edge 14 and the auxiliary cutting edge 15. That is, the cutting edge 5 is formed in a substantially L shape by the main cutting edge 14 and the sub cutting edge 15 extending so as to be substantially orthogonal to each other. The cutting insert 3 of this embodiment has a total of four (four sets) of cutting edges 5 having an L shape in this way.
The detailed configuration of the cutting insert 3 will be described later separately.
1 to 4, the cutting insert 3 is attached to an insert mounting seat 4 of the tool body 2. The cutting edge 5 of the cutting insert 3 is disposed so as to protrude to the distal end side and the radially outer side of the tool body 2.

The blade tip-exchangeable cutting tool 1 has a base end portion (shank portion) of the tool body 2 attached to a spindle or the like (not shown) of a machine tool, and is rotated in a tool rotation direction T around a tool axis O. As a result, the cutting edge-exchangeable cutting tool 1 performs a rolling process (milling process) on a work material such as a metal material by the cutting edge 5 of the cutting insert 3. The blade-tip-exchangeable cutting tool 1 is a blade-tip-exchangeable milling cutter, for example.
This cutting edge-replaceable cutting tool 1 can perform front face machining, shoulder machining, etc. on a work material, as well as performing, for example, pocket hole digging (deep digging) by ramping. Can do.

  Here, the ramping process will be described. FIG. 19 attached to this specification explains the ramping process. In the example of FIG. 19, a horizontal blade single-sided cutting insert 101 is mounted on the insert mounting seat of the tool body 100. In the ramping process, while rotating the tool body 100 about the tool axis O, the tool body 100 is moved in the tool radial direction (right side in FIG. 19) and the tool tip side with respect to the work material W as indicated by arrows in FIG. Cutting is performed so as to move obliquely downward (downward in FIG. 19) with respect to the horizontal direction. Accordingly, the main cutting edge 102, the wiping edge 103, and the ramping edge 104 of the cutting insert 101 can be cut into the work material W, for example, and pocket hole digging (deep digging) or the like can be performed.

[Definition of direction (direction) used in this specification]
In this specification, in FIGS. 1 to 4 and FIGS. 13 to 16, the direction from the shank portion toward the insert mounting seat 4 in the direction along the tool axis O of the tool body 2 (direction of the tool axis O) is the tip of the tool. This is referred to as the side (the lower side in FIGS. 3, 4, 15 and 16). Of the direction along the tool axis O of the tool body 2 (the direction of the tool axis O), the direction from the insert mounting seat 4 toward the shank is referred to as the tool base end side (upper side in FIGS. 3, 4, 15 and 16). .
A direction perpendicular to the tool axis O is referred to as a tool radial direction. Of the tool radial direction, the direction approaching the tool axis O is referred to as the inner side of the tool radial direction. Of the tool radial direction, the direction away from the tool axis O is referred to as the outside of the tool radial direction.
Further, a direction around the tool axis O is referred to as a tool circumferential direction. Of the tool circumferential directions, the direction in which the tool body 2 is rotated by the spindle of the machine tool or the like during cutting is referred to as a tool rotation direction T. Of the tool circumferential direction, the rotation direction opposite to the tool rotation direction T is referred to as the side opposite to the tool rotation direction T (counter tool rotation direction).

Moreover, in the cutting insert 3 shown by FIGS. 5-12, the imaginary straight line which passes through each center of a pair of main surface 11 is called insert main surface axis C1. In the cutting insert 3, an imaginary straight line passing through the centers of the pair of long side surfaces 12 is referred to as an insert long side axis C2. In the cutting insert 3, an imaginary straight line passing through each center of the pair of short side surfaces 13 is referred to as an insert short side surface axis C3.
That is, the insert main surface axis C <b> 1 extends through the center of one main surface 11 and the center of the other main surface 11 of the pair of main surfaces 11. The insert long side surface axis C <b> 2 extends through the center of one long side surface 12 and the center of the other long side surface 12 of the pair of long side surfaces 12. The insert short side surface axis C <b> 3 extends through the center of one short side surface 13 and the center of the other short side surface 13 of the pair of short side surfaces 13. Each of these insert axes C1 to C3 intersects each other perpendicularly at the center (center point) of the cutting insert 3.

The direction in which the insert main surface axis C1 extends (the direction along the insert main surface axis C1) is referred to as the insert main surface axis C1 direction. 6 and FIG. 8, in the side view of the cutting insert 3, the direction from the main surface 11 toward the center of the cutting insert 3 (intersection of the insert axes C1 to C3) among the insert main surface axis C1 directions The inside of the insert in the direction of the main surface axis C1 is referred to. On the contrary, the direction from the center of the cutting insert 3 toward each main surface 11 in the insert main surface axis C1 direction is referred to as the insert outer side in the insert main surface axis C1 direction. In addition, the side view of the cutting insert 3 shown by FIG. 6 is the side view which looked at the long side surface 12 in the front. Moreover, the side view of the cutting insert 3 shown by FIG. 8 is a side view which looked at the short side 13 in the front.
The direction in which the insert long side surface axis C2 extends (the direction along the insert long side surface axis C2) is referred to as the insert long side surface axis C2 direction. In the plan view of the cutting insert 3 shown in FIG. 7 and the side view of the cutting insert 3 shown in FIG. 8, the direction from each long side surface 12 to the center of the cutting insert 3 among the insert long side surface axis C2 directions is This is referred to as the inside of the insert in the direction of the long side axis C2. On the contrary, the direction from the center of the cutting insert 3 toward each long side surface 12 in the insert long side surface axis C2 direction is referred to as the insert outer side in the insert long side surface axis C2 direction. 7 is a plan view when the main surface 11 is viewed from the front.
The direction in which the insert short side surface axis C3 extends (the direction along the insert short side surface axis C3) is referred to as the insert short side surface axis C3 direction. In the side view of the cutting insert 3 shown in FIG. 6 and the plan view of the cutting insert 3 shown in FIG. 7, the direction from each short side surface 13 to the center of the cutting insert 3 among the insert short side surface axis C3 directions is This is called the inner side of the insert in the direction of the short side axis C3. On the contrary, the direction from the center of the cutting insert 3 toward each short side surface 13 among the insert short side surface axis C3 directions is referred to as the insert outer side in the insert short side surface axis C3 direction.

Moreover, in this specification, as FIG. 7 shows, the planar view which looked at the main surface 11 in front along the insert main surface axis C1 is called insert main surface axis C1 direction view. Further, as shown in FIGS. 10 and 11, a plan sectional view perpendicular to the insert main surface axis C1 is also referred to as a view in the direction of the insert main surface axis C1.
Further, as shown in FIG. 6, a side view of the long side surface 12 viewed from the front along the insert long side surface axis C2 is referred to as an insert long side surface axis C2 direction view. Also, as shown in FIG. 12, a side sectional view perpendicular to the insert long side surface axis C2 is also referred to as a view in the direction of the insert long side surface axis C2.
Further, as shown in FIG. 8, a side view of the short side surface 13 viewed from the front along the insert short side surface axis C3 is referred to as an insert short side surface axis C3 direction view. Further, as shown in FIG. 9, a side sectional view perpendicular to the insert short side surface axis C3 is also referred to as a view in the direction of the insert short side surface axis C3.

(Tool body)
1 to 4 and 13 to 16, the tool body 2 has a columnar shape or a disk shape. The tool main body 2 is rotated around the tool axis O, which is the central axis thereof, by the spindle of the machine tool or the like.
In the example of this embodiment, the tool body 2 has a cylindrical shape. Further, a portion (shank portion) other than the tip portion is formed with a larger diameter than the tip portion (blade portion) of the tool body 2.

A plurality of chip pockets 6 are formed in the outer periphery of the tip of the tool body 2 so as to be cut out in a concave shape from the outer periphery of the tip, spaced from each other in the tool circumferential direction.
In these chip pockets 6, insert mounting seats 4 to which the cutting inserts 3 are detachably attached are provided at portions located on the side opposite to the tool rotation direction T. The insert mounting seat 4 has a rectangular hole shape corresponding to the shape of the cutting insert 3.
The configuration of the insert mounting seat 4 will be described in detail after the detailed configuration of the cutting insert 3 is described.

  Although not particularly illustrated, the chip pocket 6 may be provided with a coolant hole for ejecting coolant (oil-based or water-soluble cutting fluid). In this case, the coolant hole ejects coolant (oil-based or water-soluble cutting fluid) toward the vicinity of the cutting edge 5 of the cutting insert 3 mounted on the insert mounting seat 4. The coolant hole is connected to a coolant supply means (not shown) through a main shaft of a machine tool attached to the shank portion of the tool body 2 at the base end portion. The coolant hole opens into the chip pocket 6 at the tip.

[Cutting insert]
As shown in FIGS. 5 to 12, the cutting insert 3 is formed in a 180 ° rotationally symmetric shape around the insert main surface axis C <b> 1 passing through the centers of the pair of main surfaces 11. The cutting insert 3 is formed in a 180 ° rotationally symmetric shape around the insert long side surface axis C2 passing through the centers of the pair of long side surfaces 12. Further, the cutting insert 3 is formed in a 180 ° rotationally symmetric shape around the insert short side surface axis C <b> 3 passing through the centers of the pair of short side surfaces 13.

  The distance between the pair of main surfaces 11 is smaller than the distance between the pair of long side surfaces 12 and the distance between the pair of short side surfaces 13. Moreover, the distance between a pair of long side surfaces 12 is made smaller than the distance between a pair of short side surfaces 13. Therefore, the cutting insert 3 has a rectangular plate shape in which the direction of the insert main surface axis C1 is the thickness direction (plate thickness direction).

[Mounting hole]
The cutting insert 3 is formed with attachment holes 16 that pass through the cutting insert 3 in the direction of the insert main surface axis C1 and open to the pair of main surfaces 11. As shown in FIGS. 9 and 12, the attachment hole 16 has a pair of large diameter portions 17, a small diameter portion 18, and a tapered portion 19. The large diameter portion 17 opens in the main surface 11. The small diameter portion 18 is located on the inner side of the insert in the direction of the insert principal surface axis C <b> 1 than the pair of large diameter portions 17. The taper portion 19 is disposed between the pair of large diameter portions 17 and the small diameter portion 18 to connect them. The tapered portion 19 is gradually reduced in diameter from the connecting portion with the large-diameter portion 17 toward the inside of the insert in the direction of the insert principal surface axis C <b> 1, and is smoothly connected to the small-diameter portion 18.

  As shown in FIGS. 1, 3 and 4, a clamp screw (fixing member) 20 is inserted into the mounting hole 16 of the cutting insert 3. Although not particularly illustrated, of the screw shaft portion and the head of the clamp screw 20, the screw shaft portion passes through the mounting hole 16 and is screwed into the screw hole 54 (see FIG. 13) of the insert mounting seat 4. To wear. Further, the head of the clamp screw 20 is locked to the tapered portion 19 while being accommodated in the large-diameter portion 17 of the mounting hole 16.

[Cutting edge]
As shown in FIGS. 5 to 8, the cutting insert 3 includes, as the cutting edge 5, a main cutting edge 14, a sub cutting edge 15, and a corner blade 21 that connects them. Moreover, the cutting insert 3 of this embodiment has the connection blade 22 which connects a pair of adjacent cutting blades 5 in the periphery of the long side surface 12. FIG. The cutting length of the main cutting edge 14 is longer than the cutting edge length of the auxiliary cutting edge 15, the cutting edge length of the corner cutting edge 21, and the cutting edge length of the connecting cutting edge 22. In addition, since the connecting blade 22 is an apparent cutting edge 5 portion that is not generally used for cutting, the connecting blade 22 may not be provided.

  The main cutting edge 14 is linear. The main cutting edge 14 is located on the long side of the four sides (a pair of long sides and a pair of short sides) forming the periphery of the long side surface 12. As shown in FIG. 7, the main cutting edge 14 has its end connected to the corner edge 21 disposed outside the insert in the direction of the insert long side surface axis C2. The main cutting edge 14 gradually extends from the corner blade 21 toward the inner side of the insert in the direction of the insert long side surface axis C2 while being inclined toward the insert short side surface axis C3 direction. Moreover, as FIG. 6 shows, as for the main cutting edge 14, the edge part connected to the corner blade 21 is arrange | positioned most inside the insert of the insert main surface axis C1 direction. The main cutting edge 14 is inclined and extended toward the outer side of the insert in the direction of the insert major surface axis C1 gradually from the corner blade 21 toward the insert short side surface axis C3.

  The auxiliary cutting edge 15 is located on the short side of the four sides (a pair of long sides and a pair of short sides) forming the periphery of the long side surface 12. The sub cutting edge 15 has a first sub cutting edge 31 and a second sub cutting edge 32. The first sub cutting edge 31 is connected to the main cutting edge 14 via the corner blade 21. The second sub cutting edge 32 is connected to the end of the first sub cutting edge 31 on the side opposite to the main cutting edge 14. The second secondary cutting edge 32 is an insert in the direction of the short insert side axis C3 from the end of the first secondary cutting edge 31 in the direction of the main insert axis C1 in the direction of the long insert side axis C2 shown in FIG. Inclined and extended inward.

  In the present embodiment, the first sub-cutting edge 31 among the sub-cutting edges 15 is used as a finishing cutting edge (sieving edge). The second sub cutting edge 32 is used as a cutting edge for ramping (ramping blade). Specifically, when the cutting insert 3 is mounted on the insert mounting seat 4 of the tool body 2, the first sub cutting edge 31 is disposed so as to extend in a virtual plane perpendicular to the tool axis O. Further, the second sub cutting edge 32 is disposed so as to incline and extend toward the tool base end side from the connecting portion with the first sub cutting edge 31 toward the inside in the tool radial direction.

  The first sub cutting edge 31 is linear. In the view of the insert long side surface axis C2 direction shown in FIG. 6, the first sub-cutting blade 31 has its end connected to the corner blade 21 disposed inside the insert in the direction of the insert short side surface axis C3. Moreover, the 1st sub cutting edge 31 is inclined and extended toward the insert outer side of the insert short side surface axis C3 direction gradually as it goes to the insert main surface axis C1 direction from this corner blade 21. As shown in FIG. Further, in the view of the direction of the insert short side surface axis C3 shown in FIG. 8, the end of the first sub cutting edge 31 connected to the corner blade 21 is arranged on the outermost insert side in the direction of the insert long side surface axis C2. Moreover, the 1st sub cutting edge 31 is inclined and extended toward the insert inner side of the insert long side surface axis C2 direction gradually as it goes to the insert main surface axis C1 direction from this corner blade 21. As shown in FIG.

  The second sub cutting edge 32 has a concave curve shape. Specifically, as viewed in the direction of the insert short side surface axis C3 shown in FIG. 8, the second auxiliary cutting edge 32 has a concave curve shape so as to be recessed toward the inside of the insert in the direction of the insert long side surface axis C2. Further, in the view of the insert long side axis C2 direction shown in FIG. 6, the second sub-cutting edge 32 has the end connected to the first sub-cutting edge 31 disposed outside the insert in the direction of the insert short side axis C3. ing. Further, the second sub cutting edge 32 gradually extends toward the inner side of the insert in the direction of the insert short side axis C3 from the connecting portion with the first sub cutting edge 31 in the direction of the insert main surface axis C1. . As shown in FIGS. 7 and 8, the second auxiliary cutting edge 32 is disposed so as to be recessed inside the insert in the direction of the insert long side surface axis C <b> 2 in each cutting edge 5.

  Here, a virtual plane that passes through the center of the cutting insert 3 (intersection of the insert axes C1 to C3) and is perpendicular to the insert principal surface axis C1 is considered. This virtual plane is perpendicular to the insert major surface axis C1 in FIG. 6 and includes an insert long side surface axis C2 and an insert short side surface axis C3. In the present embodiment, the connecting portion of the sub cutting edge 15 between the first sub cutting edge 31 and the second sub cutting edge 32 is disposed close to or on the virtual plane (that is, on the virtual plane). The connecting portion between the first sub-cutting blade 31 and the second sub-cutting blade 32 of the sub-cutting blade 15 is located at the approximate center in the thickness direction of the cutting insert 3 (in the direction of the insert main surface axis C1). As seen in the direction of the insert long side surface axis C2 shown in FIG. 6, the connecting portion between the first sub cutting edge 31 and the second sub cutting edge 32 protrudes outward from the insert in the direction of the short insert side axis C3. Are arranged.

  The corner blade 21 has a convex curve shape. Of the four corners of the long side surface 12, the corner blade 21 is disposed at a corner where the intersection of the extension line of the main cutting edge 14 and the extension line of the first auxiliary cutting edge 31 is located. The corner blade 21 is in contact with the cutting edges 14 and 31 while smoothly connecting the main cutting edge 14 and the first auxiliary cutting edge 31. The extension line of the main cutting edge 14 is a virtual straight line obtained by extending the main cutting edge 14 toward the sub cutting edge 15 of the same cutting edge 5. The extension line of the first sub cutting edge 31 is a virtual straight line obtained by extending the first sub cutting edge 31 to the main cutting edge 14 side of the same cutting edge 5. As shown in FIG. 7 and FIG. 8, the corner blade 21 is arranged so as to protrude to the outer side of the insert in the direction of the insert long side surface axis C <b> 2 in each cutting edge 5.

  The connecting blade 22 has a convex curve shape. As shown in FIG. 6, the connecting blade 22 has an extension line of the main cutting edge 14 among the four corners of the long side surface 12, and another cutting blade 5 including the main cutting edge 14. It is arrange | positioned in the corner | angular part in which the intersection with the extension line of the 2nd sub cutting edge 32 in the cutting edge 5 is located. As described above, the extension line of the main cutting edge 14 is a virtual straight line obtained by extending the main cutting edge 14 to the side opposite to the sub cutting edge 15 of the same cutting edge 5. The extension line of the second auxiliary cutting edge 32 is a virtual straight line obtained by extending the second auxiliary cutting edge 32 to the opposite side of the main cutting edge 14 of the same cutting edge 5. The connecting blade 22 connects a pair of substantially L-shaped cutting blades 5 adjacent to each other at the periphery of the long side surface 12. Specifically, the cutting edge 5 has an L shape having at least a main cutting edge 14, a sub cutting edge 15, and a corner edge 21. The two sets of cutting edges 5 include a pair of long sides (main cutting edge 14) and a pair of short sides (sub cutting edge 15) forming the periphery of the long side surface 12, and a pair of corners (corner blades) of the long side surface 12. 21), it is formed on the periphery of one long side surface 12. The connecting blade 22 includes the main cutting edge 14 (or the second auxiliary cutting edge 32) of one cutting edge 5 and the second cutting edge 5 of the pair of cutting edges 5 adjacent to each other at the periphery of the long side surface 12. The two secondary cutting edges 32 (or the main cutting edge 14) are smoothly connected. Further, the connecting blade 22 is in contact with these cutting blades 14 and 32.

[Main surface]
The main surface 11 has a rectangular shape. Specifically, as shown in FIG. 7, the main surface 11 is formed in a parallelogram shape. The main surface 11 is a flank (main flank) of the main cutting edge 14. The main surface 11 has a pair of inclined surface portions (first flank surfaces) 23 and a flat surface portion (second flank surface) 24 as viewed in the direction of the insert short side surface axis C3 shown in FIG. The inclined surface part 23 inclines toward the insert outer side of the insert main surface axis C1 direction as it goes from the main cutting edge 14 toward the insert long side surface axis C2. The flat surface portion 24 continues to the insert inner side of the inclined surface portion 23 in the insert long side surface axis C2 direction. The flat surface portion 24 has a planar shape perpendicular to the insert main surface axis C1.

As shown in FIG. 7, the width of the inclined surface portion 23 is the largest at the end portion on the corner blade 21 side adjacent to the main cutting edge 14. Further, the width of the inclined surface portion 23 is the smallest at the end portion on the side of the connecting blade 22 adjacent to the main cutting edge 14. That is, the width of the inclined surface portion 23 gradually decreases along the main cutting edge 14 from the corner blade 21 toward the connecting blade 22 side. Here, the width of the inclined surface portion 23 is a length from the main cutting edge 14 toward the inside of the insert in the direction of the insert long side surface axis C2.
A large diameter portion 17 of the attachment hole 16 is opened in the flat portion 24.

[Long side]
The long side surface 12 has a rectangular shape. Specifically, as shown in FIG. 6, the long side surface 12 is formed in a rectangular shape that is long in the insert short side surface axis C3 direction and short in the insert main surface axis C1 direction. The long side surface 12 is a rake face of the cutting edge 5. 9 to 11, the long side surface 12 includes a first inclined surface portion (first rake surface) 25, a second inclined surface portion (second rake surface) 26, and a flat surface portion (third rake surface). 27. The 1st inclined surface part 25 inclines toward the insert inner side of insert long side surface axis C2 direction gradually as it goes to the inner side of this long side surface 12 from the cutting blade 5. As shown in FIG. The second inclined surface portion 26 is disposed on the opposite side of the first inclined surface portion 25 from the cutting edge 5. The flat surface portion 27 is disposed on the opposite side of the second inclined surface portion 26 from the first inclined surface portion 25. The flat portion 27 has a flat shape perpendicular to the insert long side surface axis C2.

  5 and 6, the first inclined surface portion 25 extends along the cutting edge 5 formed on the outer peripheral edge of the long side surface 12. The first inclined surface portion 25 has a rectangular frame shape as a whole. The width of the first inclined surface portion 25 (the length in the direction orthogonal to the cutting edge 5) is the largest at the portion corresponding to the corner edge 21. The width of the first inclined surface portion 25 is the smallest at the portion corresponding to the connecting blade 22. Further, the width of the first inclined surface portion 25 is the largest at the end portion on the corner blade 21 side adjacent to the main cutting edge 14 in the portion corresponding to the main cutting edge 14. The width of the first inclined surface portion 25 is gradually reduced from the end portion on the corner blade 21 side adjacent to the main cutting edge 14 toward the connecting blade 22 side adjacent to the main cutting edge 14. Further, the width of the first inclined surface portion 25 is the largest at the end corresponding to the sub cutting edge 15 on the corner blade 21 side adjacent to the sub cutting edge 15 (the end of the first sub cutting edge 31). Has been. The width of the first inclined surface portion 25 is gradually reduced from the end portion on the corner blade 21 side adjacent to the auxiliary cutting edge 15 toward the connecting blade 22 side adjacent to the auxiliary cutting edge 15.

  Moreover, in this embodiment, the part corresponding to the main cutting edge 14, the part corresponding to the corner blade 21, and the part corresponding to the 1st sub cutting edge 31 among the 1st inclined surface parts 25 comprise planar shape. Yes. Moreover, the part corresponding to the 2nd sub cutting edge 32 and the part corresponding to the connection blade 22 among the 1st inclined surface parts 25 are formed in the concave curved surface shape.

The second inclined surface portion 26 extends along the first inclined surface portion 25. The second inclined surface portion 26 has a rectangular frame shape as a whole.
As shown in FIGS. 5, 8, and 9 to 11, the second inclined surface portion 26 corresponds to the portion corresponding to the main cutting edge 14, the portion corresponding to the corner blade 21, and the first auxiliary cutting edge 31. And a portion located on the first sub cutting edge 31 side in the second sub cutting edge 32 (specifically, approximately half of the blade length of the second sub cutting edge 32 on the first sub cutting edge 31 side. The portion corresponding to) is gradually inclined toward the inner side of the insert in the direction of the insert long side surface axis C2 from the first inclined surface portion 25 toward the inner side of the long side surface 12. In addition, the inclination of these parts of the 2nd inclined surface part 26 is made larger than the inclination in each part of the 1st inclined surface part 25 located in the outer side of the long side surface 12 corresponding to these parts. The inclination of the first inclined surface portion 25 and the second inclined surface portion 26 refers to the insert in the direction of the insert long side surface axis C2 per unit length toward the inside of the long side surface 12 along a virtual plane perpendicular to the insert long side surface axis C2. The amount of displacement toward the inside. Further, in the second inclined surface portion 26, a portion of the second sub cutting edge 32 that is positioned on the connecting blade 22 side (specifically, approximately half of the blade length of the second sub cutting edge 32 on the connecting blade 22 side). And the portion corresponding to the connecting blade 22 are gradually inclined toward the outside of the insert in the direction of the insert long side surface axis C2 from the first inclined surface portion 25 toward the inside of the long side surface 12 (FIG. 10). And FIG. 11).
Further, as shown in FIG. 6, the planar portion 27 has a rectangular shape.

[Short side]
The short side surface 13 has a rectangular shape. Specifically, as shown in FIG. 8, the short side surface 13 is formed in a parallelogram shape. The short side surface 13 is a flank (sub flank) of the sub cutting edge 15. The short side surface 13 has a first sub flank (a flank of the first sub cutting edge) 41 and a second sub flank (a flank of the second sub cutting edge) 42. The first auxiliary flank 41 extends from the first auxiliary cutting edge 31 of the auxiliary cutting edge 15 in the direction of the insert long side surface axis C2. The second secondary relief surface 42 extends from the second secondary cutting edge 32 in the direction of the insert long side surface axis C2. The first sub-flank 41 and the second sub-flank 42 have a rectangular shape, and are specifically formed in a trapezoidal shape. Moreover, the 1st sub flank 41 and the 2nd sub flank 42 are each formed in planar shape. The length of the second sub-flank 42 in the insert long side axis C2 direction is longer than the length of the first sub-flank 41 in the insert long side axis C2 direction.

  On the short side surface 13, the second sub flank 42 is connected to the side of the first sub flank 41 opposite to the first sub cutting edge 31 along the insert long side surface axis C <b> 2 direction. In addition, a first sub-flank 41 is connected to the side of the second sub-flank 42 opposite to the second sub-cutting edge 32 along the insert long side surface axis C2 direction. That is, in the short side surface 13, between the 1st sub cutting edge 31 and the 2nd sub cutting edge 32 which are arrange | positioned at the both ends edge of insert long side surface axis C2 direction, the 1st sub flank 41 and the 2nd sub flank A surface 42 is formed. The first sub-flank 41 and the second sub-flank 42 are connected in this order from the first sub-cutting edge 31 toward the second sub-cutting edge 32. In addition, a second sub-flank 42 and a first sub-flank 41 are formed between the second sub-cutting blade 32 and the first sub-cutting blade 31 arranged at both end edges in the insert long side surface axis C2 direction. Has been. The second sub-flank 42 and the first sub-flank 41 are connected in this order from the second sub-cutting edge 32 toward the first sub-cutting edge 31.

For this reason, the first auxiliary flank 41 and the second auxiliary flank 42 function as the flank (sub flank) of the auxiliary cutting edge 15 as follows.
That is, in the first sub cutting edge 31, the first sub flank 41 substantially functions as a first sub flank (first sub flank connected to the sub cutting edge). Further, the second auxiliary flank 42 is disposed adjacent to the first auxiliary flank 41 on the opposite side of the first auxiliary cutting edge 31 along the insert long side surface axis C2 direction, and is substantially the second auxiliary flank. It functions as a surface (second auxiliary flank counting from the secondary cutting edge).
On the other hand, in the second sub cutting edge 32, the second sub flank 42 substantially functions as a first sub flank (first sub flank connected to the sub cutting edge). Further, the first sub-flank 41 is disposed adjacent to the second sub-flank 42 on the opposite side of the second sub-cutting edge 32 along the insert long side surface axis C2 direction, and is substantially the second sub-flank. It functions as a surface (second auxiliary flank counting from the secondary cutting edge).
In the present specification, when simply referring to “the flank of the first sub cutting edge 31”, it refers to “the first sub flank 41”, and when simply referring to “the flank of the second sub cutting edge 32”. , “Second auxiliary flank 42”.

  As shown in FIGS. 7 and 10, the flank (second sub flank 42) of the second sub cutting edge 32 formed on the short side surface 13 has the second sub flank as viewed in the direction of the insert main surface axis C <b> 1. As it goes from the cutting edge 32 to the insert long side surface axis C2 direction, it inclines toward the insert outer side of the insert short side surface axis C3 direction. Further, as shown in FIG. 12, the second secondary flank 42, as viewed in the direction of the insert long side surface axis C2, from the main surface 11 adjacent to the second sub flank 42 in the direction of the insert main surface axis C1. The insert is formed to be inclined toward the outer side of the insert in the direction of the short side axis C3.

  And as FIG. 8 shows, the flank (1st sub flank 41) of the 1st subcut blade 31 formed in the short side 13 is this 1st subcut in the insert short side axis C3 direction view. The length in the direction of the insert principal surface axis C1 (that is, the “width” of the flank) is made smaller from the blade 31 toward the insert long side surface axis C2. A ridge line is formed at the boundary between the first sub-flank 41 and the second sub-flank 42 adjacent to the insert long side surface axis C2 of the first sub-flank 41. This ridge line inclines toward the insert inner side in the insert main surface axis C1 direction as it goes from the first sub cutting edge 31 toward the insert long side axis C2 direction (as it goes toward the insert inner side in the insert long side axis C2 direction). It extends. As a result, the length (width) of the first sub-flank 41 in the insert main surface axis C1 direction is gradually reduced toward the inner side of the insert in the insert long side surface axis C2 direction.

  In the present embodiment, the length (width) of the first sub-flank 41 in the insert main surface axis C1 direction is the end of the first sub-flank 41 in the insert long side axis C2 direction inside the insert. It is zero. For this reason, the flank surfaces (first sub flank surfaces 41) of the pair of first sub cutting edges 31 are separated from each other without being connected to each other. The pair of first sub cutting edges 31 are opposite to each other along the insert long side surface axis C2 direction from the pair of first sub cutting edges 31 positioned at both ends of the short side surface 13 in the insert long side surface axis C2 direction. Extends towards.

  The pair of first sub-flanks 41 formed on the short side surface 13 are formed on different planes. Specifically, the pair of first sub-flanks 41 on the short side surface 13 are formed separately. The pair of first sub-flanks 41 have mutually different plane inclinations and are not arranged in parallel. Accordingly, the pair of first sub-flanks 41 are not included in the same plane.

Further, the flank surfaces (second sub flank surfaces 42) of the pair of second sub cutting edges 32 are disposed adjacent to each other in the direction of the insert main surface axis C1. That is, the pair of second auxiliary flank surfaces 42 formed on the short side surface 13 are directly connected (intersect) adjacent to each other in the direction of the insert principal surface axis C1. Note that the flank surfaces (second sub flank surfaces 42) of the pair of second sub cutting edges 32 are from the pair of second sub cutting edges 32 located at both end edges of the short side surface 13 in the insert long side surface axis C2 direction. It extends toward the mutually opposite side along the insert long side surface axis C2 direction.
The pair of second sub-flank surfaces 42 formed on the short side surface 13 are also formed on different planes. The pair of second auxiliary flank surfaces 42 have different plane inclinations. Moreover, the 1st sub flank 41 and the 2nd sub flank 42 are formed in a mutually different plane. The first sub-flank 41 and the second sub-flank 42 have different plane inclinations.
For this reason, the short side surface 13 is formed with four different planes including at least a pair of first auxiliary flank surfaces 41 and a pair of second auxiliary flank surfaces 42.

  Moreover, the connection part (crossing ridgeline) of a pair of 2nd sub relief surfaces 42 in the short side surface 13 is extended along the insert long side surface axis C2 direction substantially, as FIG. 8 shows. Specifically, the connection part of a pair of 2nd sub relief surfaces 42 passes along the intersection of insert axis line C1-C3 in the insert short side surface axis C3 direction view. A connection portion (intersecting ridge line) between the pair of second sub-flanks 42 is slightly inclined with respect to a virtual plane perpendicular to the insert main surface axis C1. As shown in FIG. 12, the connection portion (cross ridge line) between the pair of second auxiliary relief surfaces 42 on the short side surface 13 is the shortest side surface of the insert on the short side surface 13 as viewed in the direction of the insert long side surface axis C2. It is arranged to protrude outside the insert in the direction of the axis C3.

The length (width) in the insert main surface axis C1 direction at the flank (second sub flank 42) of the second auxiliary cutting edge 32 in the view of the insert short side axis C3 shown in FIG. 8 will be described. The width of the second auxiliary flank 42 is greater than that of the second auxiliary flank 42 compared to the end of the second auxiliary flank 42 located on the opposite side of the insert long side surface axis C2 direction from the second auxiliary cutting edge 32. It is enlarged at a portion adjacent to the sub cutting edge 32.
Specifically, the width of the second auxiliary flank 42 is substantially constant in the range from the second auxiliary cutting edge 32 to the central portion of the short side surface 13 in the direction of the insert long side surface axis C2. Further, the width of the second auxiliary flank 42 is gradually reduced from the central portion toward the end located on the side opposite to the second auxiliary cutting edge 32.

Of the flank (second flank 42) of the second sub-cutting edge 32, the second sub-cutting edge 32 is located on the opposite side of the insert long side surface axis C2 direction, and the second The secondary cutting edge 32 is adjacent to the flank (first secondary flank 41) of the first secondary cutting edge 31 located at the edge opposite to the insert long side surface axis C2 direction in the direction of the insert main surface axis C1. Are arranged. In the example of the present embodiment, on the short side surface 13, the end portion of the second auxiliary flank 42 is disposed adjacent to the outer side of the insert in the insert principal surface axis C <b> 1 direction with respect to the first auxiliary flank 41. .
Further, the flank (second sub flank 42) of the second sub cutting edge 32 formed on the short side surface 13 is opposite to the second sub cutting edge 32 in the short side surface 13 in the direction of the insert long side surface axis C2. It does not reach the first sub-cutting edge 31 located at the side edge.

[Insert restraint angle of cutting insert]
The flank face (second flank face 42) of the second secondary cutting edge 32 formed on the short side surface 13 and the insert long side axis line C2 of the short side surface 13 as viewed in the direction of the insert main surface axis C1 shown in FIG. And a flat surface portion 27 of the long side surface 12 connected to the short side surface 13 via a first sub cutting edge 31 located on the edge opposite to the second sub cutting edge 32 along the direction. This angle is defined as a first insert restraint angle θ1. The first insert restraint angle θ1 is less than 90 °.
In addition, when viewed in the direction of the insert long side surface axis C2 shown in FIG. 12, one second sub flank 42 and the other second sub flank out of the pair of second sub flank 42 formed on the short side 13. An angle formed between the flat portion 24 of the main surface 11 adjacent to 42 is a second insert restraint angle θ2. The second insert restraint angle θ2 is less than 90 °.

(Insert mounting seat)
As shown in FIGS. 13 to 16, the insert mounting seat 4 of the tool body 2 includes a main surface mounting wall 51, a long side surface mounting wall 52, and a short side surface mounting wall 53. The main surface mounting wall 51 faces the outer side in the tool radial direction and is brought into contact with the main surface 11 of the cutting insert 3. The long side surface mounting wall 52 faces the tool rotation direction T and is brought into contact with the long side surface 12 of the cutting insert 3. The short side surface mounting wall 53 faces the tool tip side, and is located on the outer side in the tool radial direction among the flank surfaces (second sub flank surfaces 42) of the pair of second sub cutting edges 32 formed on the short side surface 13. It is made to contact | abut to the 2nd sub flank 42 to do.

  The main surface mounting wall 51 has a planar shape. The main surface attachment wall 51 is brought into contact with the flat portion 24 in the main surface 11 of the cutting insert 3. The main surface mounting wall 51 has a rectangular shape corresponding to the shape of the main surface 11. As shown in FIG. 14, the main surface mounting wall 51 is formed to be inclined toward the outer side in the tool radial direction as it goes in the tool rotation direction T. Further, as shown in FIG. 15, the main surface mounting wall 51 is formed so as to be inclined toward the inner side in the tool radial direction toward the tool tip side. The main surface mounting wall 51 has a screw hole 54 into which the screw shaft portion of the clamp screw 20 is screwed.

  The long side mounting wall 52 has a planar shape. The long side mounting wall 52 is brought into contact with the flat portion 27 on the long side surface 12 of the cutting insert 3. The long side surface mounting wall 52 has a rectangular shape corresponding to the shape of the long side surface 12. As shown in FIG. 16, the long side surface mounting wall 52 is formed to be inclined toward the side opposite to the tool rotation direction T as it goes toward the tool tip side.

The short side mounting wall 53 has a planar shape. The short side surface mounting wall 53 is disposed outside the tool radial direction when the cutting insert 3 is mounted on the insert mounting seat 4 among the pair of second auxiliary flank surfaces 42 on the short side surface 13 of the cutting insert 3. It is made to contact | abut with respect to one 2nd sub flank 42. FIG.
Specifically, the short side mounting wall 53 is brought into contact with only one of the second auxiliary flank faces 42 arranged on the outer side in the tool radial direction, out of the pair of second auxiliary flank faces 42 of the short side face 13. It does not contact the other second auxiliary flank 42 arranged on the inner side in the radial direction.
The short side mounting wall 53 has a rectangular shape (trapezoidal shape) corresponding to the shape of the second auxiliary flank 42. As shown in FIG. 15, the short side surface mounting wall 53 is formed to be inclined toward the tool tip side as it goes outward in the tool radial direction. Further, as shown in FIG. 16, the short side surface mounting wall 53 is formed so as to be inclined toward the tool tip side in the tool rotation direction T.

What is indicated by reference sign θ1 in FIG. 16 is an angle (first insert restraint angle) formed between the short side surface mounting wall 53 and the long side surface mounting wall 52 in the insert mounting seat 4, and this angle θ1 is , Less than 90 °. The angle θ1 of the insert mounting seat 4 is equal to the first insert restraint angle θ1 of the cutting insert 3 shown in FIG.
Further, what is indicated by reference sign θ2 in FIG. 15 is an angle (second insert restraint angle) formed between the main surface mounting wall 51 and the short side surface mounting wall 53 in the insert mounting seat 4 and this angle. θ2 is less than 90 °. The angle θ2 of the insert mounting seat 4 is equal to the second insert restraint angle θ2 of the cutting insert 3 shown in FIG.

[Mounting posture of the cutting insert to the insert mounting seat, etc.]
1 to 4, when the cutting insert 3 is mounted on the insert mounting seat 4, one main surface 11 facing the inner side in the tool radial direction is the insert mounting among the pair of main surfaces 11 of the cutting insert 3. The seat 4 is brought into contact with a main surface mounting wall 51 facing outward in the tool radial direction. Further, the other main surface 11 is disposed facing the outer side in the tool radial direction, and serves as a flank of the main cutting edge 14. Of the pair of long side surfaces 12 of the cutting insert 3, one long side surface 12 facing away from the tool rotation direction T abuts on the long side surface mounting wall 52 facing the tool rotation direction T in the insert mounting seat 4. Be made. The other long side surface 12 is arranged facing the tool rotation direction T and is a rake face of the cutting edge 5 (the main cutting edge 14, the corner edge 21 and the auxiliary cutting edge 15). In addition, of the pair of short side surfaces 13 of the cutting insert 3, one short side surface 13 facing the tool base end side is brought into contact with the short side surface mounting wall 53 facing the tool distal end side in the insert mounting seat 4. The other short side surface 13 is arranged facing the tool front end side, and serves as a flank of the auxiliary cutting edge 15.

  In FIG. 3, when the cutting insert 3 is mounted on the insert mounting seat 4, although not particularly illustrated, the insert long side surface axis C <b> 2 of the cutting insert 3 gradually approaches the tool tip side toward the tool rotation direction T. Inclined and extended toward. Further, the insert short side surface axis C3 is gradually inclined toward the side opposite to the tool rotation direction T toward the tool tip side. And insert short side axis C3 is inclined and extended toward the inner side of a tool radial direction gradually toward the tool tip side. Further, the insert main surface axis C1 extends while being inclined toward the tool tip side gradually toward the outer side in the tool radial direction.

[Effects of this embodiment]
According to the cutting insert 3 of this embodiment described above and the cutting edge-exchangeable cutting tool 1 using the same, the auxiliary cutting edge 15 of the cutting insert 3 includes the first auxiliary cutting edge 31 and the second auxiliary cutting edge 32. ,have. The first sub cutting edge 31 continues to the main cutting edge 14. The second sub cutting edge 32 is connected to the end of the first sub cutting edge 31 on the side opposite to the main cutting edge 14. The second sub-cutting edge 32 extends obliquely from the end of the first sub-cutting edge 31 toward the insert inner side in the direction of the insert short side axis C3 as it goes in the direction of the insert main plane axis C1. Therefore, as in the present embodiment, of the sub cutting edges 15, the first sub cutting edge 31 is used as a finishing cutting edge (scraping blade), and the second sub cutting edge 32 is used as a ramping cutting edge (ramping). Blade).

  Specifically, when the cutting insert 3 is mounted on the insert mounting seat 4 of the tool body 2, the first sub cutting edge 31 is arranged in a virtual plane perpendicular to the tool axis O. Thereby, the 1st sub cutting edge 31 can be used as a wiping edge. Further, the second sub cutting edge 32 is inclined toward the tool base end side from the connecting portion with the first sub cutting edge 31 toward the inside in the tool radial direction. Thereby, the 2nd sub cutting edge 32 can be used as a ramping blade.

  Thereby, not only can the face cutting or shoulder cutting (peripheral cutting) process be performed on the work material by one cutting edge-replaceable cutting tool 1, but also, for example, pocket hole digging by ramping ( Deep digging) and the like. Therefore, it is possible to consolidate the tools while reducing the number of tool types, and it is possible to continuously perform various cutting processes and to shorten the processing time.

Further, the flank (second sub flank 42) of the second sub cutting edge 32 formed on the short side surface 13 of the cutting insert 3 is inserted from the second sub cutting edge 32 toward the insert long side surface axis C2. It is inclined toward the outer side of the insert in the direction of the short side axis C3. Accordingly, the clearance angle of the second auxiliary cutting edge 32 when the cutting insert 3 is viewed as a single unit is set to a negative angle (negative angle). Therefore, a large blade angle of the second auxiliary cutting edge 32 can be ensured.
That is, when the second sub cutting edge 32 is used as a ramping blade as described above, a large cutting resistance tends to act on the second sub cutting edge 32. However, since the second sub-cutting edge 32 has a large blade angle, the cutting edge strength can be increased, and the cutting edge defect and the like can be suppressed and stable cutting can be performed.

  When the cutting edge-replaceable cutting tool 1 is viewed as a whole, the mounting posture of the cutting insert 3 to the insert mounting seat 4 is set as in this embodiment, so that the substantial relief of the second sub cutting edge 32 is achieved. The angle can be set to a positive angle. That is, the flank (second sub flank 42) of the second sub-cutting edge 32 is inclined toward the tool base end side from the second sub-cutting edge 32 toward the side opposite to the tool rotation direction T. Further, the cutting insert 3 is disposed on the insert mounting seat 4. Thereby, the clearance angle of the 2nd sub-cutting edge 32 at the time of a cutting process can be set to a positive angle substantially. Furthermore, the contact between the second auxiliary flank 42 and the work surface of the work material is prevented, and good cutting can be performed.

In addition, since the clearance angle of the second auxiliary cutting edge 32 is set to a negative angle as the cutting insert 3 alone, an effect of improving the seating stability of the cutting insert 3 with respect to the insert mounting seat 4 can be obtained. it can.
Specifically, when the cutting insert 3 is mounted on the insert mounting seat 4 of the tool body 2, as shown in FIGS. 3 and 4, a short side mounting wall facing the tool tip side in the insert mounting seat 4 is shown. 53 of the flank faces (second flank face 42) of the pair of second sub cutting edges 32 of the short side face 13 facing the short side surface mounting wall 53, the second sub flank position located outside in the tool radial direction. It is brought into contact with the surface 42. Further, the long side surface mounting wall 52 facing the tool rotation direction T in the insert mounting seat 4 is brought into contact with the long side surface 12 facing the long side surface mounting wall 52. For this reason, when the cutting insert 3 is viewed inward in the tool radial direction (when the main surface 11 is viewed from the insert main surface axis C1 direction), the short side mounting wall 53 and the long side surface of the insert mounting seat 4 are viewed. The angle θ1 (first insert restraint angle, see FIG. 16) formed between the mounting wall 52 and the mounting wall 52 can be set to an angle smaller than 90 °. Accordingly, the pulling force (indicated by reference numeral F1 in FIG. 16) toward the apex side of the angle θ1 with respect to the cutting insert 3 restrained by the short side mounting wall 53 and the long side mounting wall 52 of the insert mounting seat 4. Force in the direction of the arrow) can be generated. Thereby, rattling (lifting) of the cutting insert 3 at the time of cutting is suppressed, and seating stability can be improved.

Further, the flank (second sub flank 42) of the second sub cutting edge 32 moves from the main surface 11 adjacent to the second sub flank 42 toward the insert main surface axis C1 direction along the insert short side surface axis C3. In this configuration, the effect of improving the seating stability of the cutting insert 3 with respect to the insert mounting seat 4 can be obtained.
Specifically, when the cutting insert 3 is mounted on the insert mounting seat 4 of the tool body 2, as shown in FIG. 3, a short side mounting wall 53 facing the tool tip side in the insert mounting seat 4 is Of the flank surfaces (second sub flank surfaces 42) of the pair of second sub cutting edges 32 on the short side surface 13 facing the short side surface mounting wall 53, the second sub flank surface 42 located on the outer side in the tool radial direction. Abutted. Further, the main surface mounting wall 51 facing the outside in the tool radial direction in the insert mounting seat 4 is brought into contact with the main surface 11 facing the main surface mounting wall 51. For this reason, when the cutting insert 3 is viewed toward the side opposite to the tool rotation direction T (when the long side surface 12 is viewed from the front from the insert long side surface axis C2 direction), the short side surface mounting wall 53 of the insert mounting seat 4 is used. The angle θ2 (second insert restraint angle; see FIG. 15) formed between the main surface mounting wall 51 and the main surface mounting wall 51 can be set to an angle smaller than 90 °. Accordingly, a pulling force (indicated by reference numeral F2 in FIG. 15) toward the apex side of the angle θ2 with respect to the cutting insert 3 constrained by the short side mounting wall 53 and the main surface mounting wall 51 of the insert mounting seat 4. Force in the direction of the arrow) can be generated. Thereby, rattling (lifting) of the cutting insert 3 at the time of cutting is suppressed, and seating stability can be improved.

The flank (first sub flank 41) of the first sub cutting edge 31 formed on the short side surface 13 of the cutting insert 3 is inserted from the first sub cutting edge 31 toward the insert long side axis C2 direction. The length (width) in the main surface axis C1 direction is reduced. Thereby, according to this embodiment, the area of the flank (2nd sub flank 42) of the 2nd sub cutting edge 32 is securable.
Specifically, as shown in FIG. 8, the first auxiliary cutting edge 31 and the second auxiliary cutting edge 32 that are located at both end edges of the short side surface 13 in the direction of the insert long side surface axis C <b> 2 are flank surfaces of each other. (The first auxiliary flank 41 and the second auxiliary flank 42) are arranged adjacent to each other. For this reason, as described above, the flank (first sub flank 41) of the first sub cutting edge 31 is formed so that the width becomes narrower from the first sub cutting edge 31 toward the insert long side surface axis C2. Therefore, the flank (second sub-flank 42) of the second sub-cutting blade 32 adjacent to the flank (first sub-flank 41) of the first sub-blade 31 is It forms so that a width | variety may become large as it goes to the insert long side surface axis C2 direction from the 1st sub cutting edge 31. FIG.

  As a result, the short side surface mounting wall 53 facing the tool tip side in the insert mounting seat 4 can be brought into contact with the flank (second sub flank 42) of the second sub cutting edge 32 over a wide range. The cutting insert 3 can be stably fixed to the insert mounting seat 4. Therefore, the effect that the above-described seating stability of the cutting insert 3 can be enhanced becomes even more remarkable.

Further, the flank surfaces (first sub flank surfaces 41) of the pair of first sub cutting edges 31 formed on the short side surface 13 are formed on different planes. Thereby, the 1st sub flank 41 can be variously formed with a restriction | limiting according to the desired cutting performance.
Specifically, for example, the clearance angle of the first sub cutting edge 31 when the cutting insert 3 is viewed as a single unit is set to a negative angle (negative angle), and the blade angle of the first sub cutting edge 31 is set to be the same. It can be secured greatly. Alternatively, the clearance angle of the first secondary cutting edge 31 is set to a positive angle (positive angle), and the rake angle is increased to the positive side while ensuring the clearance angle of the first secondary cutting edge 31 during cutting. Can improve sharpness. When the clearance angle of the first secondary cutting edge 31 is set to a positive angle, the first side clearance surface 41 and the second secondary clearance surface 42 adjacent to each other in the insert long side surface axis C2 direction on the short side surface 13 are arranged. In addition, it is preferable to arrange another plane (connection surface) for connecting these flank surfaces.
That is, according to the present embodiment, the flank surfaces (first sub flank surfaces 41) of the pair of first sub cutting edges 31 formed on the short side surface 13 are formed as separate planes. For this reason, the first auxiliary flank surfaces 41 are less likely to affect each other's arrangement, shape, inclination, and the like. Thereby, it is possible to suppress the cutting edge angle, clearance angle, and the like of the first sub cutting edge 31 from being restricted, and to significantly improve cutting performance such as chipping resistance and machining accuracy of the cutting edge.

  From the above, according to the cutting insert 3 of the present embodiment and the cutting edge-exchangeable cutting tool 1 using the cutting insert 3, ramping can be performed as well as face cutting and shoulder cutting. In addition, according to the cutting insert 3 of this embodiment and the cutting edge-exchangeable cutting tool 1 using the cutting insert 3, the seating stability of the cutting insert 3 on the insert mounting seat 4 at the time of cutting can be improved, and the cutting performance Can be improved.

In the present embodiment, the clearance angle of the second secondary cutting edge 32 is a negative angle, or the clearance surface (second secondary clearance surface 42) of the second secondary cutting edge 32 is the second secondary clearance surface 42. By inclining toward the insert outer side in the direction of the insert short side surface axis C3 as it goes from the main surface 11 adjacent to the direction of the insert main surface axis C1, the following effects can be obtained.
That is, in the cutting insert 3 mounted on the insert mounting seat 4 of the tool body 2, the tool rotation direction T of the main cutting edge 14 with respect to the rotation trajectory around the tool axis O of the main cutting edge 14 used for cutting processing. The corners (see FIG. 2) of the cutting insert 3 located rearward can be arranged closer to the inside in the tool radial direction than the rotation locus. Therefore, it is possible to stably improve the cutting accuracy. In addition, the corner | angular part of the cutting insert 3 mentioned above is the edge part of the insert outer side of the insert principal surface axis line C1 direction of the 2nd sub cutting edge 32 located in the opposite side to the tool rotation direction T rather than the main cutting edge 14 ( It is located at the outer end in the tool radial direction.

Specifically, in the conventional vertical blade double-sided type cutting insert, it is difficult to ensure the second clearance of the main cutting edge. In the cutting insert, it is more difficult to ensure the second clearance especially as the diameter of the rotation trajectory of the main cutting edge becomes smaller (that is, as the cutting diameter becomes smaller).
On the other hand, according to the present embodiment, as described above, the corner of the cutting insert 3 positioned behind the tool rotation direction T of the main cutting edge 14 with respect to the rotation trajectory of the main cutting edge 14 is set in the tool radial direction. It is easy to set it back inside. For this reason, even if it is a case where the processing diameter of cutting is made into the small diameter, the 2nd relief of the main cutting edge 14 can be ensured, and processing accuracy can be maintained favorable. Note that it is generally known that the end portion of the main cutting edge 14 on the tool front end side is easily affected by bending due to a cutting load. If the second escape amount is ensured as in the present embodiment, damage to the tool can be reliably suppressed even when bending occurs, and the tool life can be extended.

Further, in this embodiment, the flank (second sub flank 42) of the second sub cutting edge 32 formed on the short side surface 13 of the cutting insert 3 is different from the second sub cutting edge 32 on the short side surface 13. Since it does not reach the first sub cutting edge 31 located at the end edge on the opposite side of the insert long side surface axis C2 direction, the following effects are obtained.
That is, in this case, the second auxiliary flank 42 prevents the second auxiliary cutting edge 32 from affecting the shape of the first auxiliary cutting edge 31 located at the edge opposite to the insert long side surface axis C2 direction. it can. At the same time, a large area of the second auxiliary flank 42 can be secured as described above. For example, when the second auxiliary flank 42 is simply formed large, the second auxiliary flank 42 is an edge of the short side surface 13 opposite to the second auxiliary cutting edge 32 in the direction of the insert long side surface axis C2. It is conceivable that the first auxiliary cutting edge 31 located at the position 1 may be reached and the shape and function of the first auxiliary cutting edge 31 may be affected. According to the configuration of the present embodiment, such a problem can be prevented. Therefore, the first sub-cutting edge 31 can be made to function stably as a wiping edge, for example, while the above-described operational effect by the second sub-flank 42 is remarkably obtained.

Moreover, in this embodiment, the main surface 11 (the inclined surface portion 23) of the cutting insert 3 is in the direction of the insert main surface axis C1 as it goes from the main cutting edge 14 toward the insert long side surface axis C2 in the direction of the insert short side surface axis C3. Since it is inclined toward the outer side of the insert, the following effects are obtained.
That is, in this case, as the flank of the main cutting edge 14 formed on the main surface 11 of the cutting insert 3 (the inclined surface portion 23 which is the first flank) moves from the main cutting edge 14 toward the insert long side surface axis C2. It inclines toward the insert outer side of the insert principal surface axis C1 direction. For this reason, the clearance angle of the main cutting edge 14 when the cutting insert 3 is viewed as a single body is set to a negative angle (negative angle). Therefore, a large blade angle of the main cutting edge 14 can be secured.

  Specifically, in the vertical blade type cutting insert 3 as in the present embodiment, generally heavy cutting (high efficiency processing) is required. The vertical blade type cutting insert 3 is required to have a high rigidity capable of withstanding a large cutting resistance especially on the main cutting edge 14 due to high cutting and high feed. For this reason, as long as the blade angle of the main cutting edge 14 is secured as described above, the strength of the cutting edge can be sufficiently increased, the chipping of the cutting edge is suppressed, and stable cutting (particularly heavy cutting). It can be performed.

In this embodiment, the length (width) of the flank (second sub flank 42) of the second sub cutting edge 32 in the insert main surface axis C1 direction is the second sub flank 42 of the second sub flank 42. The second sub-cutting edge 32 is larger at the portion adjacent to the second sub-cutting edge 32 than the end located on the opposite side of the insert long side surface axis C2 direction, and therefore has the following effects.
That is, in this case, the above-described operation effect of the present embodiment that the cutting insert 3 is restrained by the short side surface mounting wall 53 and the long side surface mounting wall 52 of the insert mounting seat 4 to improve the seating stability is more remarkable. It will be something. That is, the short side surface mounting wall 53 of the insert mounting seat 4 is separated from the long side surface mounting wall 52 in the short side surface mounting wall 53 (near the end in the tool rotation direction T of the short side surface mounting wall 53). The second sub-flank 42 can be contacted over a wide range. Thereby, the restraining force of the cutting insert 3 by the short side surface mounting wall 53 and the long side surface mounting wall 52 can be remarkably increased, and rattling of the cutting insert 3 can be reliably suppressed.

In the present embodiment, a pair of second auxiliary cutting edges 32 positioned at both edges of the short side surface 13 in the insert long side surface axis C2 direction and extending toward opposite sides along the insert long side surface axis C2 direction. Since the flank surfaces (a pair of second sub flank surfaces 42) of the second sub cutting edge 32 are arranged adjacent to each other in the direction of the insert main surface axis C1, the following operational effects are obtained.
That is, in this case, the pair of second sub-flanks 42 are directly adjacent to each other without interposing another surface therebetween. For example, the flank (first sub flank 41) of the first sub cutting edge (sweeper blade) 31 is not interposed between the second sub flank surfaces 42. Therefore, according to the above configuration, the area of the second sub-flank 42 is further ensured. Thereby, the short side surface mounting wall 53 facing the tool front end side in the insert mounting seat 4 can contact the second sub-flank 42 in a wide range. The effect that the above-mentioned seating stability of the cutting insert 3 can be improved becomes more remarkable.

Second Embodiment
Next, the cutting insert 30 of the cutting edge exchange type cutting tool according to the second embodiment will be described with reference to FIGS. 17 and 18.
Detailed description of the same components as those of the above-described embodiment will be omitted, and only differences will be described below.

[Differences from the previous embodiment]
The cutting edge replaceable cutting tool of the present embodiment has a common tool body 2 and a cutting insert 30 different from the cutting edge replaceable cutting tool 1 described in the above embodiment. Specifically, the configuration of the short side surface 13 of the cutting insert 30 is mainly different.

  As shown in FIG. 17 and FIG. 18, the cutting insert 30 of the present embodiment includes an insert long side surface axis from a pair of first auxiliary cutting edges 31 positioned at both end edges of the short side surface 13 in the insert long side surface axis C2 direction. The flank faces (a pair of first flank faces 41) of the pair of first sub cutting edges 31 extending toward opposite sides along the C2 direction are connected to each other.

Specifically, in FIG. 18, the pair of first sub-flanks 41 on the short side surface 13 has a length in the insert main surface axis C1 direction from the first sub cutting edge 31 toward the insert long side surface axis C2 ( The width is reduced. The pair of first auxiliary flank surfaces 41 are connected to each other on the insert short side surface axis C3.
Further, in this way, a pair of second second ends extending from the pair of second auxiliary cutting edges 32 located at both ends of the short side surface 13 in the insert long side surface axis C2 direction toward the opposite sides along the insert long side surface axis C2 direction. The flank surfaces (a pair of second sub flank surfaces 42) of the sub-cutting blades 32 are separated from each other without being connected to each other.

The pair of first sub-flanks 41 formed on the short side surface 13 are formed on different planes. The pair of first sub-flanks 41 of the short side surface 13 have mutually different plane inclinations and are not arranged in parallel (thus not included in the same plane).
Specifically, the flank surfaces (a pair of first sub flank surfaces 41) of the pair of first sub cutting edges 31 on the short side surface 13 are opposite to the first sub cutting edges 31 along the insert long side surface axis C2 direction. Although the edge parts located in are connected, they are formed by mutually different planes. The pair of first sub-flanks 41 intersect each other at this connection portion. In other words, the pair of first sub-flanks 41 are connected so as to be twisted via the connection portions, and ridge lines or valley lines are formed in the connection portions.

In addition, the pair of second sub-flank surfaces 42 formed on the short side surface 13 are also formed on different planes, and these planes have different inclinations. Moreover, the 1st sub flank 41 and the 2nd sub flank 42 are formed in a mutually different plane, and these planes differ in inclination.
For this reason, the short side surface 13 is formed with four different planes including at least a pair of first auxiliary flank surfaces 41 and a pair of second auxiliary flank surfaces 42.

[Effects of this embodiment]
According to the cutting insert 30 of this embodiment and the cutting edge-exchange-type cutting tool using the same, the same effects as those of the above-described embodiment can be obtained.

<Third Embodiment>
A cutting insert 130 of a cutting edge exchangeable cutting tool according to a third embodiment of the present invention will be described. FIG. 20 is a cross-sectional view of the blade tip replaceable tool to which the cutting insert 130 of the third embodiment is attached. FIG. 21 is an enlarged view of a region XXI in FIG.
Detailed description of the same components as those of the above-described embodiment will be omitted, and only differences will be described below.

  The cutting edge replaceable cutting tool of the present embodiment has a common tool body 2 and a cutting insert 130 different from the cutting edge replaceable cutting tool 1 described in the above embodiment. Specifically, the configuration of the mounting hole 116 of the cutting insert 130 is different.

  The cutting insert 130 of this embodiment is provided with a mounting hole 116 as in the first embodiment. The attachment hole 116 is provided so as to penetrate in a direction (one direction) orthogonal to the pair of main surfaces 11. A clamp screw (fixing member) 20 for fixing the cutting insert 130 to the tool body 2 is inserted into the mounting hole 116.

  The clamp screw 20 includes a shaft portion 20b on which a male screw is formed, and a head portion (locking portion) 20a located at one end of the shaft portion 20b. The head portion 20a is formed with a larger diameter than the shaft portion 20b. The head 20a has a conical shape. The seating surface 20c of the head 20a constitutes a tapered surface that decreases in diameter toward the connecting portion with the shaft portion 20b.

  The attachment hole 116 is provided with a pair of large diameter portions 117, a pair of taper portions 119, and a small diameter portion 118. The pair of large diameter portions 117 open to the main surface 11 facing the opposite sides. The small diameter portion 118 is located between the pair of large diameter portions 117. The pair of taper portions 119 are disposed between the large diameter portion 117 and the small diameter portion 118 and connect them. One large-diameter portion 117, one tapered portion 119, small-diameter portion 118, the other tapered portion 119 and the other large-diameter portion 117 are formed in this order along the insertion direction of the clamp screw 20.

The taper portion 119 decreases the diameter of the attachment hole 116 from each main surface 11 toward the inside. That is, the tapered portion 119 reduces the diameter of the mounting hole 116 along the insertion direction of the clamp screw 20.
As shown in FIG. 21, the taper portion 119 has a first R portion (curved portion) 119a at the end portion on the side having a smaller hole diameter (that is, the end portion on the small diameter portion 118 side). The taper portion 119 is smoothly connected to the small diameter portion 118 via the first R portion 119a. Similarly, the taper portion 119 has a second R portion 119b at an end portion on the side where the hole diameter is large (that is, an end portion on the large diameter portion 117 side). The tapered portion 119 is smoothly connected to the large diameter portion 117 via the second R portion 119b. The cutting insert 130 contacts the seat surface 20c formed in the taper shape of the clamp screw 20 in the first R portion 119a.

  The tapered portion 119 has a polishing portion 109. The polishing portion 109 is formed in a strip shape and along the entire circumference along the circumferential direction of the taper portion 119. The cutting insert 130 is in contact with a tapered seat surface 20 c provided on the head 20 a of the clamp screw 20 in the polishing portion 109. Therefore, the polishing portion 109 is formed at least in the first R portion 119a of the tapered portion 119.

  The polishing unit 109 is formed by, for example, blasting or brushing. The arithmetic average roughness Ra of the polishing portion 109 is 0.35 μm or less, preferably 0.30 μm or less. The polishing unit 109 is in contact with the seating surface 20 c of the clamp screw 20.

[Effects of this embodiment]
In the cutting insert 130 of the present embodiment, the attachment holes 116 are provided through the pair of main surfaces 11, and a rake surface is provided on the side surface connecting the peripheral edges of the pair of main surfaces 11. That is, the cutting insert 130 is a so-called vertical blade type cutting insert. In this case, a large shear stress is applied to the clamp screw 20 during cutting. When the shaft diameter of the clamp screw is increased in order to suppress the breakage of the clamp screw against a large shear stress, the cutting insert becomes thin accordingly. For this reason, there was a problem that the cutting insert was easily cracked.

According to the cutting insert 130 of the present embodiment, the polishing portion 109 is provided in a portion that contacts the seat surface 20c of the clamp screw 20. The stress accompanying the fastening of the clamp screw 20 is applied to the portion in contact with the seating surface 20c. A defect on the surface of the contact portion becomes a starting point of the crack. In a cemented carbide used as a constituent material of a general cutting insert 130, fine defects due to tungsten carbide grains are formed on the surface. In particular, when manufacturing a vertical-blade double-sided type cutting insert, a molded body is first manufactured by press molding of the raw material powder, but since the insert is formed from the direction of the insert long side surface axis C2, a part of the periphery of the mounting hole is low. The density tends to be high, and surface defects due to this low density are likely to occur after sintering. By providing the polishing portion 109 in the contact portion, it is possible to remove the defect that becomes the starting point of the crack, and to prevent the cutting insert 130 from being cracked. Further, by making the arithmetic average roughness Ra of the polishing portion 109 0.35 μm or less, the occurrence of cracks is more reliably suppressed.
Note that the cutting insert 130 of the present embodiment is provided with a polishing portion 109 on the entire portion of the clamp screw 20 that contacts the head 20a. However, if the polishing part 109 is provided in at least a part of the contacted part, a certain effect is exerted on the generation of cracks.

  According to the present embodiment, the tapered portion 119 of the attachment hole 116 is in contact with the tapered seat surface 20c. Thereby, relative alignment of the center axis of the mounting hole 116 and the center axis of the clamp screw 20 is facilitated. Further, since the seating surface 20c of the clamp screw 20 comes into contact with the first R portion 119a of the tapered portion 119, the posture of the cutting insert 130 can be easily adjusted when the clamp screw 20 is fastened. However, on the other hand, the contact area of the cutting insert 130 and the clamp screw 20 decreases because the seating surface 20c comes into contact with the cutting insert 130 in the first R portion 119a. Thereby, the stress added to the cutting insert 130 from the clamp screw 20 increases. According to the present embodiment, since the polishing portion 109 is provided at the contact portion between the cutting insert 130 and the clamp screw 20 and the generation of cracks is suppressed, the cutting insert even when the stress at the contact portion increases. Damage to 130 can be suppressed.

[Other configurations]
The present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the spirit of the present invention.

  For example, in the above-described embodiment, the first sub-flank 41 and the second sub-flank 42 formed on the short side surface 13 of the cutting inserts 3 and 30 have a rectangular shape, specifically a trapezoidal shape. Although described as being formed, it is not limited to this. That is, the shape of the first sub-flank 41 and the second sub-flank 42 may be, for example, a polygonal shape other than a rectangular shape, an oval shape, an elliptical shape, or the like.

  In addition, in the range which does not deviate from the meaning of this invention, you may combine each structure (component) demonstrated by the above-mentioned embodiment, a modification, and a remark etc., addition of a structure, omission, substitution, others It can be changed. Further, the present invention is not limited by the above-described embodiments, and is limited only by the scope of the claims.

  The cutting insert 130 according to the third embodiment described above, and an example in which the polishing portion 109 is provided in a contact portion with the clamp screw 20 (that is, the first R portion 119a) and no polishing portion. Comparative examples were prepared. The arithmetic average roughness Ra of the contact portion is shown in Table 1 below. The arithmetic average roughness Ra was measured in an analysis region of 20 μm × 20 μm in a non-contact type laser measuring device. In addition, the measurement value is not corrected in consideration of the cutoff value.

  The cutting inserts 130 of the examples and comparative examples are attached to the tool body 2 having a diameter of 25 mm by four, and the cutting speed is 160 m / min, the axial cutting depth is 7.5 mm, and the radial cutting width is 12.5 mm. A cutting test was performed by changing the rotation speed (feed amount per blade) of the tool body 2. As a work material, SCM440 was used.

  When the feed amount per blade is increased, the load applied to the cutting insert 130 is increased, and the cutting insert 130 is easily damaged. In the cutting test, breakage of the cutting insert 130 when the feed amount per blade was changed was confirmed, and the feed amounts at the time of breakage are summarized in Table 1. In Table 1, “◯” indicates that there was no breakage in a 5-pass cutting test with 1 pass taken as 400 mm. Further, “x” indicates that breakage occurred midway.

  As shown in Table 1, in the cutting insert 130 of the example, breakage could be suppressed as compared with the comparative example. From this result, it was confirmed that the breakage of the cutting insert 130 can be suppressed by providing a polishing portion at the contact portion between the cutting insert 130 and the clamp screw 20.

  As described above, according to the cutting insert and the cutting edge exchange type cutting tool of the present invention, it is possible to perform face machining and shoulder machining as well as ramping. Moreover, according to the cutting insert and cutting edge exchange-type cutting tool of this invention, the seating stability of the cutting insert to the insert mounting seat at the time of cutting can be improved, and cutting performance can be improved.

DESCRIPTION OF SYMBOLS 1 Cutting edge exchange type cutting tool 2 Tool main body 3, 30, 130 Cutting insert 4 Insert mounting seat 10 Side surface 11 Main surface (main flank surface)
12 Long side (rake face)
13 Short side (sub-flank)
14 Main cutting edge 15 Sub cutting edge 16, 116 Mounting hole 20 Clamp screw (fixing member)
20a Head (locking part)
21 Corner blade 31 1st sub cutting edge 32 2nd sub cutting edge 41 1st sub flank (flank of 1st sub cutting edge)
42 Second auxiliary flank (flank of the second auxiliary cutting edge)
51 Main surface mounting wall 52 Long side surface mounting wall 53 Short side surface mounting wall 119 Tapered portion 119a First R portion (curved portion)
C1 insert main surface axis C2 insert long side surface axis C3 insert short side surface axis O tool axis T tool rotation direction

Claims (6)

A cutting insert that is detachably attached to the tip of a tool body that rotates about a tool axis,
A mounting hole penetrating in one direction is provided, and a fixing member having a shaft portion and a locking portion located at one end of the shaft portion is inserted into the mounting hole and fixed to the tool body,
The mounting hole is provided with a tapered portion that reduces the diameter of the mounting hole along the insertion direction of the fixing member,
The tapered portion has a polishing portion in at least a part of a portion that contacts the locking portion of the fixing member.
Cutting insert. The mounting hole is provided through a pair of main surfaces,
A rake face is provided on the side face connecting the peripheral edges of the pair of main faces.
The cutting insert according to claim 1. The mounting hole has a small diameter portion located at an end portion on the side where the hole diameter of the tapered portion is small,
The tapered portion has a curved portion that smoothly connects to the small diameter portion;
Contacting the locking portion of the fixing member at the curved portion;
Cutting insert.
The cutting insert according to claim 1 or 2. The arithmetic average roughness Ra of the polished portion is 0.35 μm or less,
The cutting insert as described in any one of Claims 1-3. It has a pair of main surfaces that are front and back surfaces of the cutting insert,
The mounting hole is provided through the pair of main surfaces,
The mounting hole is provided with a pair of taper portions that reduce the diameter inward from each main surface.
The cutting insert as described in any one of Claims 1-4. The cutting insert according to any one of claims 1 to 4,
A tool body that is provided with a mounting seat in which a screw hole is formed at the tip and rotates about an axis;
The screw inserted into the screw hole and fixing the cutting insert to the mounting seat, and
The blade-tip-exchangeable cutting tool according to any one of claims 1 to 5.

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