JP5835337B2 - Cutting inserts and cutting tools - Google Patents

Description

  The present invention relates to a cutting edge-exchangeable cutting tool, and more particularly to a technique of a cutting insert and a tool body having high seating stability.

  Some types of cutting edge exchangeable cutting tools include a type in which a cutting insert is detachably attached to an insert mounting seat by inserting a screw into a screw hole of an insert mounting seat of a tool body through a through hole of the cutting insert. Such a cutting tool can employ various mechanisms for firmly fixing (clamping) the cutting insert to the insert mounting seat, for example, in order to improve the processing quality.

  For example, as shown in Patent Document 1 or Patent Document 2, in order to fix the cutting insert to the insert mounting seat, the screw is inserted obliquely with respect to the bottom wall surface of the insert mounting seat through the through hole of the cutting insert. This can contribute to improvement of the clamping force of the insert. Alternatively, conventionally, a so-called offset process (centering) that shifts the center axis of the through hole of the cutting insert and the center axis of the screw hole of the insert mounting seat is applied, whereby the clamping force of the cutting insert to the insert mounting seat is applied. To increase.

US2008 / 0199264 JP-A-7-164213

  However, when the screw is inserted obliquely with respect to the bottom wall surface of the insert mounting seat, the cutting insert comes into contact with the insert mounting seat in a so-called one-sided state where the screw contacts only a part of the wall surface that defines the through hole of the cutting insert. Fixed. Therefore, in this mechanism, the cutting insert cannot be uniformly pressed against the bottom wall surface of the insert mounting seat, and there is room for improvement with respect to the seating stability of the cutting insert on the insert mounting seat.

  On the other hand, in the application of offset machining, the screw strongly presses a part of the wall surface defining the through hole of the cutting insert, and in particular, a large bending moment can be applied to the screw from the cutting insert. This affects the life of the screw and may reduce the overall fixing performance of the cutting insert.

  An object of the present invention is to provide a cutting insert and a cutting edge exchangeable cutting tool that enables a cutting insert to be firmly and stably fixed to an insert mounting seat of a tool body.

  The present invention can provide a cutting insert and a cutting edge replaceable cutting tool based on the following three technical ideas. The first technical idea is that the cutting edge of the cutting insert has a rotationally symmetric shape with respect to the central axis of the through hole. The second technical idea is that an end surface having a function as a seating surface of the cutting insert has a plurality of surfaces. The third technical idea is that each of the plurality of surfaces is inclined with respect to a surface determined so that the central axes of the through holes are orthogonal to each other.

  The cutting insert which concerns on 1 aspect of this invention is extended through the 1st end surface and the 2nd end surface on the opposite side substantially with respect to this 1st end surface, The through-hole by which a center axis is defined, 1st A plurality of cutting edges arranged in a rotationally symmetrical manner with respect to the central axis at the intersecting ridge line portion between the end surface and the peripheral side surface extending between the first end surface and the second end surface; A plurality of divided surface portions that are rotationally symmetrical with respect to each other, each divided surface portion being associated with one of the plurality of cutting edges, and a plane that is defined so that the central axis is orthogonal to each other And a plurality of dividing surface portions formed so as to have a predetermined inclination.

  Preferably, each dividing surface portion is formed so as to incline toward the first end surface as it is away from the central axis on a plane that is defined so as to cross the dividing surface and include the central axis. More preferably, the plurality of dividing surface portions are formed to extend along each of a plurality of planes defined so as to intersect with each other at approximately one point on the central axis.

  Moreover, the cutting edge exchange type cutting tool which concerns on the further aspect of this invention is equipped with the tool main body which has at least 1 insert mounting seat, and the above-mentioned cutting insert is detachably mounted to this insert mounting seat. The insert mounting seat of the cutting edge replaceable cutting tool includes a cutting edge that is enabled when the cutting insert is mounted on the insert mounting seat so that one of the plurality of cutting blades can be used. The abutting surface portion with which the split surface portion associated with the blade abuts, and the cutting insert when the cutting insert is attached to the insert mounting seat so that one of the plurality of cutting blades can be used. A screw hole in which a hole axis extending so as to be parallel to the central axis of the through hole is defined.

  The foregoing and / or other aspects and advantages of embodiments of the present invention will be more readily understood from the following detailed description, taken in conjunction with the accompanying drawings, in which:

FIG. 1 is a plan view of a cutting insert according to the first embodiment of the present invention. FIG. 2 is a right side view of the cutting insert of FIG. FIG. 3 is a rear view of the cutting insert of FIG. FIG. 4 is a front view of the cutting insert of FIG. FIG. 5 is a bottom view of the cutting sensor of FIG. FIG. 6 is a perspective view of the cutting insert of FIG. 1 viewed obliquely from above. FIG. 7 is a perspective view of the cutting insert of FIG. 1 as viewed obliquely from below. FIG. 8 is a front view of the cutting edge-exchangeable cutting tool according to the first embodiment of the present invention. FIG. 9 is a view of the cutting tool of FIG. 8 as viewed from the front end side. FIG. 10 is a perspective view of the cutting tool of FIG. FIG. 11 is a partially enlarged view of the cutting tool of FIG. FIG. 12 is a partially enlarged view of the cutting tool of FIG. 13 is an assembly view of the insert mounting seat of the cutting tool of FIG. FIG. 14 is an enlarged perspective view of an insert mounting seat to which the cutting insert is not attached in the cutting tool of FIG. 15 is an enlarged perspective view from another direction of the insert mounting seat of FIG. 14 in which the cutting insert is not attached in the cutting tool of FIG. FIG. 16 is a partially enlarged cross-sectional view of one insert mounting seat on which one cutting insert is arranged and its surroundings in the cutting tool of FIG. FIG. 17 is a plan view of a cutting insert according to the second embodiment of the present invention. 18 is a right side view of the cutting insert of FIG. 19 is a rear view of the cutting insert of FIG. 20 is a bottom view of the cutting insert of FIG. FIG. 21 is a perspective view of the cutting insert of FIG. FIG. 22 is an enlarged view of a portion around the insert mounting seat to which the cutting insert of FIG. 17 is attached in the cutting edge-exchangeable cutting tool according to the second embodiment of the present invention. FIG. 23 is a plan view of a cutting insert according to the third embodiment of the present invention. FIG. 24 is a right side view of the cutting insert of FIG. FIG. 25 is a rear view of the cutting insert of FIG. FIG. 26 is a bottom view of the cutting insert of FIG. FIG. 27 is a perspective view of the cutting insert of FIG. FIG. 28 is a plan view of a cutting insert according to the fourth embodiment of the present invention. FIG. 29 is a right side view of the cutting insert of FIG. 30 is a rear view of the cutting insert of FIG. FIG. 31 is a bottom view of the cutting insert of FIG. FIG. 32 is a perspective view of the cutting insert of FIG.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings as appropriate. However, in the following description and drawings, the same reference numerals are used for the same or similar components throughout a plurality of embodiments, and duplicate descriptions thereof are omitted.

  First, the shape of the cutting insert and the cutting edge replacement type cutting tool according to the first embodiment of the present invention will be described. The cutting insert 1 of 1st Embodiment is shown by FIGS.

  As shown in FIG. 1, the cutting insert 1 according to the first embodiment is substantially circular in a plan view. The cutting insert 1 comprises two end faces 2, 3 that are substantially opposite, ie substantially opposite to each other, and a peripheral side face 4 extending between them. A through hole 5 extending so as to penetrate these two end faces is formed, and a central axis A is defined in the through hole 5. The cutting insert 1 has a shape that is 120 ° rotationally symmetric with respect to the central axis A.

  Here, for ease of explanation, one end surface (corresponding to the first end surface of the present invention) 2 of the two end surfaces is hereinafter referred to as an “upper surface”, and the other end surface of the two end surfaces (the present invention). 3) is hereinafter referred to as a “lower surface”. In addition, the direction from the lower surface 3 to the upper surface 2 in the axis A direction is referred to as “upward”, and the direction from the upper surface 2 to the lower surface 3 in the axis A direction is referred to as “downward”. However, the terms “above” and “below” are not intended to limit the present invention and are not intended to be construed in a limited manner based on these terms.

  The upper surface 2 of the cutting insert 1 has three divided portions 2a, 2b and 2c having the same shape. Hereinafter, since the three portions 2a, 2b, and 2c are divided surface portions of the upper surface 2, they are called “divided upper surface portions”. And in order to distinguish them easily, here, they can be referred to as first to third divided upper surface portions. As shown in FIG. 1, the three division | segmentation upper surface parts 2a, 2b, and 2c are connected via the interposition part 2d, and are formed away with respect to each other. However, the three divided upper surface portions may be continuous.

  The first to third divided upper surface portions 2a, 2b, and 2c are arranged around the through hole 5 and are arranged to be 120 ° rotationally symmetric with respect to the central axis A of the through hole 5, and the upper surface 2 of the cutting insert 1 is The shape is rotationally symmetric with respect to the central axis A by 120 °. In the present embodiment, each of the divided upper surface portions has a fan-shaped shape around the central axis A.

  In the cutting insert of the present embodiment, the divided upper surface portions 2a, 2b, and 2c are formed so as to extend along a single plane that is defined so as to correspond to each of the divided upper surface portions 2a, 2b, and 2c. It is configured as a flat surface. Cutting edges are formed along the edges of each of the first to third divided upper surface portions 2a, 2b, and 2c, that is, the intersecting ridge line portion between each divided upper surface portion and the peripheral side surface 4. . Hereinafter, the symbol “6a” is used for the first cutting edge formed at the edge portion of the first divided upper surface portion 2a, and the symbol “6b” is used for the second cutting edge formed at the edge portion of the second divided upper surface portion 2b. The symbol “6c” can be used for the third cutting edge formed at the edge of the third divided upper surface portion 2c.

  Here, when a plane F perpendicular to the central axis A is defined, the first divided upper surface portion 2a is not parallel to the plane F but inclined so as to form a predetermined angle with the plane F. The relationship between the first divided upper surface portion 2a and the plane F is similarly established between the other second and third divided upper surface portions 2b and 2c and the plane F, and will be described in detail later.

  Then, the first divided upper surface portion 2a is a plane that inclines toward the upper surface 2 side as it is away from the axis A on a plane that crosses the first divided upper surface portion 2a and includes the central axis A. Inclined with respect to F. Therefore, the portion on the central axis A side of the first divided upper surface portion 2a is positioned downward in the direction of the central axis A than the portion on the peripheral side surface 4 side of the first divided upper surface portion 2a. The same applies to the second divided upper surface portion 2b and the third divided upper surface portion 2c. And these 1st-3rd division | segmentation upper surface parts 2a, 2b, 2c are mutually related with respect to each other so that three planes defined so that they may extend may cross at one point on the central axis A in general. That is, these divided upper surface portions are formed so as to extend along each of three planes defined so as to intersect with each other at approximately one point on the central axis A. Therefore, the upper surface 2 extends so as to define a recess.

  Here, first, the inclination of one first divided upper surface portion 2a out of the three divided upper surface portions will be further described. The inclination angle θa of the first divided upper surface portion 2a with respect to the plane F can be determined on a plane that is defined to cross the first divided upper surface portion 2a and include the central axis A. Here, in particular, the inclination angle θa is determined in a plane (hereinafter, referred to as “bisected plane”) that divides the first divided upper surface portion 2a into two equal parts where the angle is the largest. That is, the inclination angle θa of the first divided upper surface portion 2a with respect to the plane F corresponds to the angle in the cross section of the first divided upper surface portion 2a of the cutting insert 1 along the line α in FIG. 1 and can be represented in FIG. . As is apparent from FIG. 2, the angle θa is an acute angle and is greater than 0 ° and less than 90 °. As described above, a surface (hereinafter referred to as an upper extension surface) that is defined to extend the first divided upper surface portion 2 a is less than 90 ° with respect to a plane F that is defined to be orthogonal to the central axis A of the through hole 5. Intersect at an angle of

  Each of the second and third divided upper surface portions 2b and 2c is also divided into two equal parts so as to include the central axis A and to divide the divided upper surface portion into two equal parts. In the plane, inclination angles θb and θc with respect to the plane F can be determined. The inclination angle θb of the second divided upper surface portion 2b with respect to the plane F and the inclination angle θc of the third divided upper surface portion 2c with respect to the plane F are the same as the inclination angle θa (θa = θb = θc), respectively. Therefore, the upper extension surfaces determined to extend the second and third divided upper surface portions 2b and 2c also intersect the plane F at an angle of less than 90 °.

  Similarly to the upper surface 2, the lower surface 3 of the cutting insert 1 has three divided portions 3a, 3b, and 3c having the same shape. Hereinafter, the three portions 3a, 3b, and 3c are respectively divided surface portions of the lower surface 3, and hence are referred to as “divided lower surface portions”. And in order to distinguish them easily, here, they can be referred to as first to third divided lower surface portions. As shown in FIGS. 5 and 7, the three divided lower surface portions 3 a, 3 b, and 3 c are connected via the interposition portion 3 d and are formed apart from each other. However, the three divided lower surface portions may be continuous.

  The first divided lower surface portion 3a has a corresponding relationship with the first divided upper surface portion 2a and the first cutting edge 6a, and when the divided upper surface portion 2a is slid parallel to the direction of the axis A, the first divided upper surface portion that has been slid It extends to overlap 2a. In short, the first divided lower surface portion 3a is located below the first divided upper surface portion 2a, particularly directly below. In other words, the first divided upper surface portion 2a is located above the first divided lower surface portion 3a, particularly directly above. Located in. Similarly, the second divided lower surface portion 3b is in a corresponding relationship with the second divided upper surface portion 2b and the second cutting edge 6b, and is positioned downward, in particular, directly below the second divided upper surface portion 2b. Corresponds to the third divided upper surface portion 2c and the third cutting edge 6c, and is positioned downward, in particular, directly below the third divided upper surface portion 2c.

  Each of the first to third divided lower surface portions 3a, 3b, 3c is formed so as to extend along a single plane determined so as to correspond to each of them, and is configured as a particularly flat surface here. . And these division | segmentation lower surface parts 3a, 3b, 3c are formed in parallel with the respectively corresponding division | segmentation upper surface parts 2a, 2b, 2c. Therefore, the 1st division | segmentation lower surface part 3a inclines with respect to the plane F, and makes the said inclination-angle (theta) a with respect to the plane F in a corresponding bisection plane. Similarly, the second divided lower surface portion 3b is inclined with respect to the plane F, and in the corresponding bisecting plane, the inclination angle θb is formed with respect to the plane F, and the third divided lower surface portion 3c is with respect to the plane F. The inclination angle θc is formed with respect to the plane F in the corresponding bisected plane. Therefore, the planes defined so as to extend the divided lower surface portions 3a, 3b, and 3c (hereinafter referred to as “lower extended surfaces”) intersect the plane F at an angle of less than 90 °. As described above, in the present embodiment, the inclination angle of the divided lower surface portion with respect to the plane F is also that of the corresponding divided upper surface portion among the planes that are defined so as to cross the divided lower surface portion and include the central axis A. It is defined in a bisection plane. This is because the angle of the divided lower surface portion with respect to the plane F is the largest in the bisecting plane.

  As is clear from the above description, the first divided lower surface portion 3a has an upper surface 2 as it moves away from the axis A on a plane that crosses the first divided lower surface portion 3a and includes the central axis A. It is formed so as to be inclined to the side. The same applies to the second divided lower surface portion 3b and the third divided lower surface portion 3c. And these 1st-3rd division | segmentation lower surface parts 3a, 3b, 3c are formed so that it may extend along each of several planes defined so that it may mutually cross | intersect at one point on the central axis A. . Therefore, by extending each of the three divided lower surface portions 3a, 3b, and 3c, a triangular pyramid having a tip end pointed downward in the cutting insert 1 is formed, and the apex of the triangular pyramid is on the axis A. Located in.

  Each divided lower surface portion is provided with one protrusion so as to protrude from the divided lower surface portion. The first divided lower surface 3a is provided with a first protrusion 7a, the second divided lower surface 3b is provided with a second protrusion 7b, and the third divided lower surface 3c is provided with a third protrusion 7c. ing. The three protrusions have the same shape, are disposed adjacent to and around the through hole 5, and are arranged to be 120 ° rotationally symmetric with respect to the axis A, similarly to the three divided bottom surfaces. Each projecting portion has two projecting end surface portions that extend from a side surface portion connected to the divided lower surface portion on which the projecting portion is provided and extend so as to substantially face the downward direction of the axis A.

  The protruding portion 7a provided on the first divided lower surface portion 3a has two protruding end surface portions 7ab and 7ac having different inclinations. The two protrusion end surface portions 7ab and 7ac are each configured as a flat surface. One projecting end surface portion 7ab of the projecting portion 7a of the first divided lower surface portion 3a extends on a lower extended surface determined so as to extend a second divided lower surface portion 3b different from the first divided lower surface portion 3a. In this way, it is positioned closer to the second divided lower surface portion 3b than the other projection end surface portion 7ac. The other protruding end surface portion 7ac of the protruding portion 7a of the first divided lower surface portion 3a extends on a lower extended surface that is determined to extend a third divided lower surface portion 3c different from the first divided lower surface portion 3a. It is formed in this way, and is positioned closer to the third divided lower surface portion 3c than the one projection end surface portion 7ab.

  The second protrusion 7b of the second divided lower surface 3b and the third protrusion 7c of the third divided lower surface 3c have the same characteristics as the first protrusion 7a of the first divided lower surface 3a. The second projecting portion 7b of the second divided lower surface portion 3b includes two flat projecting end surface portions 7ba and 7bc, and one projecting end surface portion 7ba is defined as a lower extension that extends the first divided lower surface portion 3a. The other projecting end surface portion 7bc is formed so as to extend on a lower extension surface that is defined so as to extend the third divided lower surface portion 3c. The third projecting portion 7c of the third divided lower surface portion 3c includes two flat projecting end surface portions 7ca and 7cb, and one projecting end surface portion 7ca is a lower extension defined to extend the first divided lower surface portion 3a. The other projecting end surface portion 7cb is formed so as to extend on a lower extended surface that is defined so as to extend the second divided lower surface portion 3b.

  FIG. 2 shows a lower extension surface P defined to extend the divided lower surface portion 3a. On the surface P, the protruding end surface portion 7ca of the protruding portion 7c extends.

  The first projecting portion 7a is divided into two equal parts by the bisection plane defined including the axis A so as to substantially bisect each of the first divided upper surface part 2a and the first divided lower surface part 3a. Is done. Two projecting end surface portions 7ab and 7ac are arranged symmetrically with respect to the bisecting plane. The same applies to the second protrusion 7b and the third protrusion 7c.

  The peripheral side surface 4 of the cutting insert 1 mainly has three side surfaces 4 a, 4 b, and 4 c so as to correspond to the configurations of the upper surface 2, the lower surface 3, and the protruding portion 7. The first side surface 4a extends between the first divided upper surface portion 2a and the first divided lower surface portion 3a. The second side surface 4b extends between the second divided upper surface portion 2b and the second divided lower surface portion 3b. The third side surface 4c extends between the third divided upper surface portion 2c and the third divided lower surface portion 3c. The first, second, and third cutting edges 6a, 6b, and 6c are formed at the edges of the first, second, and third side surfaces 4a, 4b, and 4c.

  Three cutout portions 8 are formed on the peripheral side surface 4. The three notches 8 are formed at positions that are rotationally symmetrical by 120 ° with the central axis A as the center. As will be described later, the surface of the notch 8 is a portion that comes into contact with the side wall of the insert mounting seat when the cutting insert 1 is attached to the tool body. Each notch is formed so as to extend over two of the three side surfaces of the peripheral side surface 4. In the cutting insert 1, each notch is formed so as to be biased to one of the two side surfaces and is formed to be continuous with the lower surface 3. However, each notch may be formed so as to extend between the two side surfaces. In the present embodiment, since the notch portion 8 is formed so as to be biased to one of the two side surfaces, the bisector plane does not strictly divide the corresponding divided lower surface portion into two halves. However, when the notch is not provided, the bisected plane can extend so as to bisect the corresponding divided lower surface.

  The cutting insert 1 having the above-described configuration is detachably attached to the insert mounting seat 12 of the tool body 11 of the cutting edge exchangeable cutting tool 10 of the present embodiment using screws that are mechanical attachment means. With reference to FIG. 8 to FIG. 16, the blade tip exchangeable cutting tool 10 to which the cutting insert 1 is attached will be further described.

  The cutting tool 10 includes a tool body 11 provided with a plurality of insert mounting seats 12. The cutting insert 1 can be detachably attached to each insert mounting seat 12. In addition, this invention does not exclude the cutting tool provided with the tool main body provided with only one insert mounting seat.

  The tool body 11 is configured to rotate around a rotation axis O determined to pass through the tool body 11 from the rear end portion to the front end portion. Around the tip of the tool body 11, five insert mounting seats are arranged at equal intervals (see FIG. 9). Therefore, the cutting tool 10 is a rotary cutting tool.

  The cutting insert 1 is attached to one insert mounting seat 12 of the tool body 11 so that the upper surface 2 faces in the rotation direction K around the rotation axis O. The insert mounting seat 12 includes a bottom wall portion 13 and a side wall portion 14 and is open toward the outer periphery on the front end side of the tool body.

  The cutting insert is arranged on the insert mounting seat and fixed with a screw S so that one cutting edge of the cutting insert 1 can be used. Hereinafter, the structure of the insert mounting seat will be specifically described by taking as an example a case where the cutting insert 1 is mounted on the insert mounting seat 12 so that the first cutting edge 6a can be used. In the illustrated cutting tool 10, the cutting insert 1 is attached to the insert mounting seat 12 using the first cutting edge 6 a as a used cutting edge. The case where the cutting insert 1 is attached to the insert mounting seat using the second cutting edge 6b or the third cutting edge 6c as the use cutting edge is the same as that of the first cutting edge 6a.

  The bottom wall portion 13 of the insert mounting seat 12 is formed with a first abutted surface portion 13a, a second abutted surface portion 13b, a recess portion 13c, and a screw hole 13d. The first abutted surface portion 13a is a substantially flat surface portion, and a recessed portion 13c and a screw hole 13d are disposed in the middle thereof. The second abutted surface portion 13b is positioned on the back side of the bottom wall portion 13, and is not on the extension of the first abutted surface portion 13a. 13 d of screw holes are formed in the middle of the 1st to-be-contacted surface part 13a, and are located in the back | inner side adjacent to the hollow part 13c.

  When the cutting insert 1 is attached to the insert mounting seat 12 so that the first cutting edge 6a can be used, the first divided lower surface portion 3a related to the first cutting edge 6a and the first divided lower surface portion 3a. And the projection end surface portion 7ba of the second projection portion 7b of the second divided lower surface portion 3b and the projection end surface portion 7ca of the third projection portion 7c of the third divided lower surface portion 3c, which are formed so as to extend on the same plane. The first abutted surface portion 13a is formed so as to abut on the first abutted surface portion 13a. The first divided lower surface portion 3a, the projecting end surface portion 7ba, and the projecting end surface portion 7ca are simultaneously in contact with the first abutted surface portion 13a, that is, the surface portions 3a, 7ba, 7ca The recessed portion 13c is positioned and formed so that the first protrusion 7a positioned therebetween is accommodated in the recessed portion, that is, the recessed portion 13c. The recess 13c of the insert mounting seat 12 is adapted to the shape of the protrusion of the cutting insert 1.

  As shown in FIG. 16, the screw hole 13 d is formed obliquely with respect to the first contacted surface portion 13 a of the bottom wall portion 13. The inclination of the screw hole can be determined between the hole axis B of the screw hole and the plane H determined so as to include the first contacted surface portion 13a. In particular, the inclination of the screw hole 13d is determined in a plane that includes the axis B and is defined to be orthogonal to the plane H. FIG. 16 is also a cross-sectional view in a plane that includes the axis B and is defined to be orthogonal to the plane H. In this plane, the insert mounting seat 12 is used so that the cutting insert 1 can use the first cutting edge 6a. The insert mounting seat 12 is formed so that the above-mentioned bisection planes of the first cutting edge 6a and the first divided upper surface portion 2a overlap.

  In FIG. 16, a line C defined to be orthogonal to the plane H is shown. In FIG. 16, the screw hole 13d is inclined with respect to the first contact surface portion 13a so that the axis B of the screw hole 13d forms an inclination angle θs with respect to the line C. The inclination angle θs is equal to the inclination angle θa, θb or θc.

  The second abutted surface portion 13b of the bottom wall portion 13 of the insert mounting seat 12 is related to the first cutting edge 6a when the cutting insert is attached to the insert mounting seat 12 so that the first cutting edge 6a can be used. Other than the attached first divided lower surface portion 3a, the boundary portion between the second and third divided lower surface portions 3b and 3c, that is, the interposition portion 3d is formed thereon. The side wall portion 14 of the insert mounting seat is formed so as to connect to the second abutted surface portion 13b.

  The side wall portion 14 of the insert mounting seat 12 has a shape that matches the peripheral side surface 4 of the cutting insert 1. Two step portions 14a and 14b are formed on the side wall portion 14 (see FIGS. 14 to 16). One step portion 14a of the two step portions is formed at a portion of the side wall portion 14 facing the tip outer peripheral side of the tool body 11, and the other step portion 14b of the two step portions is a side wall portion. 14 is formed at a portion facing the tip side of the tool body 11. These step portions are positioned such that when the cutting insert 1 is attached to the insert mounting seat 12, the two notch portions 8 formed in the cutting insert 1 abut against the corresponding step portions 14a and 14b. Are shaped.

  A coolant injection hole 15 is formed in the vicinity of the insert mounting seat 12. The coolant can be supplied to the injection holes through a supply passage (not shown) formed so as to extend in the tool body 11 from the rear end portion to the tip portion of the tool body 11 during cutting. As a result, coolant is sprayed toward the cutting insert 1.

  The operation and effect of the cutting insert described above and the cutting tool to which it is attached will be described below.

  As described above, the cutting insert 1 includes the divided lower surface portions 3 a, 3 b, and 3 c that are rotationally symmetrical with respect to the axis A of the through hole 5. Each of the divided lower surface portions 3a, 3b, and 3c is formed to be inclined at a predetermined inclination with respect to a plane F that is determined to be orthogonal to the axis A of the through hole 5. In addition, the first contacted surface portion 13a of the insert mounting seat 12 of the tool body 11 is in contact with the projecting end surface portion of the projecting portion of the divided lower surface portion and the other divided lower surface portion with respect to the usable cutting edge. Is formed. The screw hole 13d of the insert mounting seat 12 has a predetermined angle that is substantially the same as the predetermined angle of the insert with respect to the line C that is defined to be perpendicular to the first contacted surface portion 13a. Is formed obliquely with respect to the first abutted surface portion 13a. Therefore, in such an insert mounting seat 12, the cutting insert 1 is disposed so that the axis A of the through hole 5 and the axis B of the screw hole 13 d are preferably parallel to each other, and the screw S is inserted into the through hole. The cutting insert 1 is attached and fixed by being screwed into the screw hole 13 d through 5. Therefore, the screw S can cause the cutting insert 1 to exert a force that presses the cutting insert 1 substantially uniformly against the first abutted surface portion 13a spreading around the screw hole of the insert mounting seat. Therefore, the cutting insert 1 is firmly fixed to the insert mounting seat 12.

  Further, as described above, the cutting insert 1 includes the above-described three divided lower surface portions, and has the substantially triangular pyramid-shaped lower surface 3 that protrudes downward in the cutting insert as a whole. On the other hand, the insert mounting seat forms a pocket shape, that is, a recess, with the bottom wall portion and the side wall portion having the abutted surface portion. Therefore, the cutting insert is disposed on the insert mounting seat so that the cutting insert fits into a space defined by the plurality of wall surfaces of the insert mounting seat. In this state, as described above, the screw exerts a force pressing the cutting insert 1 toward the bottom wall portion and the side wall portion of the insert mounting seat, so that the cutting insert is firmly fixed by the insert mounting seat.

  Further, when the cutting insert is attached to the insert mounting seat so that the first cutting edge 6a can be used, the cutting blade that can be used on the second abutting surface portion 13b of the bottom wall portion of the insert mounting seat Portions other than the related divided lower surface portions are placed. Therefore, the seating stability of the cutting insert on the insert mounting seat is improved. In the cutting insert 1 and the cutting tool 10, only one interposition part 3d abuts against the second abutted surface part 13b, so that the abutting area of the cutting insert against the second abutted part is compared. Narrow. The second contact surface portion may be formed in a shape that is more suitable for the shape of the cutting insert, and the contact region of the cutting insert with respect to the second contact surface portion may be widened.

  Further, the step portions 14 a and 14 b are formed on the side wall portion 14 of the insert mounting seat, and the two notches 8 formed in the cutting insert 1 when the cutting insert 1 is mounted on the insert mounting seat 12. Are in contact with the corresponding stepped portions. Therefore, sufficient contact between the cutting insert and the insert mounting seat is further ensured, and the seating stability of the cutting insert 1 at the insert mounting seat is further enhanced.

  Furthermore, when the cutting insert 1 is attached to the insert mounting seat 12, the protrusion 7 a, 7 b or 7 c of the cutting insert 1 is accommodated in the recess 13 c of the insert mounting seat 12. Therefore, the seating stability of the cutting insert 1 at the insert mounting seat 12 is further enhanced by the engagement between the recess and the projection. Therefore, even when a force for rotating the cutting insert 1 is applied to the cutting insert 1 during cutting with the cutting tool 10, the cutting insert 1 is more reliably prevented from sliding on the insert mounting seat 12 and attempting to rotate. (Rotation prevention effect)

  Thus, since the cutting insert is firmly fixed to the insert mounting seat, an offset process for shifting the axis of the through hole of the cutting insert and the axis of the screw hole of the insert mounting seat is unnecessary. Therefore, in the cutting insert and the cutting tool, the bending moment is suppressed from being applied to the mounting screw, and the load applied to the screw is preferably equalized. For this reason, the life of the screw can be extended, and thereby the life of the cutting insert and the tool body can be extended.

  Further, in the cutting insert 1, the divided upper surface portion is formed to be inclined with respect to the plane F so as to form an angle of less than 90 ° with respect to the plane F. Therefore, when the cutting insert is disposed and attached to the insert mounting seat, it is possible to prevent the axial rake from becoming significantly negative, and it is preferable to easily make the axial rake positive. Thereby, the fall of the cutting insert sharpness can be suppressed or improved.

  Next, a second embodiment of the present invention will be described. The cutting insert 101 of 2nd Embodiment is represented by FIGS.

  The cutting insert 101 is different from the cutting insert 1 of the first embodiment in that the protrusion 7 is not provided on the lower surface 3. Regarding other configurations, the cutting insert 101 is substantially the same as the cutting insert 1.

  FIG. 22 shows a state in which the cutting insert 101 is attached to an insert mounting seat formed at the tip of the tool body of the cutting tool according to the second embodiment. In addition, FIG. 22 is drawing equivalent to FIG. 12 regarding 1st Embodiment.

  As shown in FIG. 22, in the second embodiment, the bottom wall portion 13 of the insert mounting seat 12 has a more suitable shape along the shape of the lower surface 3 of the cutting insert 1. That is, the bottom wall portion 13 of the insert mounting seat 12 is formed so that the three divided lower surface portions of the cutting insert abut around the screw hole. In particular, the second abutted surface portion 13b is formed so that the divided lower surface portions 3b and 3c that are not related to the usable cutting edge 6a abut. Therefore, in the cutting insert and cutting tool of the second embodiment, a large contact area between the cutting insert and the bottom wall portion of the insert mounting seat is further ensured, and the cutting insert can be firmly fixed to the insert mounting seat.

  And since the cutting insert 101 is provided with the above-mentioned three division | segmentation lower surface parts, the lower surface 3 as a whole protrudes toward the downward direction of the cutting insert rather than the cutting insert 1 of 1st Embodiment. It has a cone shape. On the other hand, the insert mounting seat forms a substantially triangular pyramid-shaped pocket, that is, a recess, by a bottom wall portion having a shape corresponding to the three divided lower surface portions. Therefore, the seating stability of the cutting insert on the insert mounting seat is increased, and the cutting insert is more securely fixed to the insert mounting seat more securely against the force of rotating the cutting insert.

  In addition, 2nd Embodiment similarly has the effect | action and effect demonstrated regarding the said 1st Embodiment except the point regarding a projection part.

  Next, a third embodiment of the present invention will be described. The cutting insert 201 of the third embodiment is shown in FIGS.

  The cutting insert 201 has a 180 ° rotationally symmetric shape with respect to the central axis A of the through-hole 5 and includes two rectangular bottom surfaces 3a and 3b. Each of the divided lower surface portions 3a and 3b is a substantially flat surface and is disposed so as to form a substantially V shape.

  Each of the divided lower surface portions 3a and 3b also has a predetermined inclination with respect to a plane F that is determined so that the central axis A is orthogonal, as in the divided lower surface portion of the first embodiment. Each of the divided lower surface portions 3a and 3b is a plane that inclines toward the upper surface 2 side with increasing distance from the axis A on a plane that crosses the divided lower surface portion and includes the central axis A. Inclined with respect to F. Moreover, these division | segmentation lower surface parts 3a and 3b are related with respect to each other so that two planes defined so as to extend them may intersect on the central axis A.

  Two protruding portions 7a and 7b are provided on each divided lower surface portion. The two projecting portions 7a provided on one divided lower surface portion 3a are disposed so as to face the two projecting portions 7b provided on the other divided lower surface portion 3b.

  The projecting end surface portions 7ab of the two projecting portions 7a provided on the first divided lower surface portion 3a are formed so as to extend on the extended surface of the second divided lower surface portion 3b. Similarly, the projection end surface portions 7ba of the two projection portions 7b provided on the second divided lower surface portion 3b are also formed to extend on the extended surface of the first divided lower surface portion 3a. With such a shape, when one of the divided lower surface portions comes into contact with the contacted surface portion of the bottom wall portion of the insert mounting seat, the protrusion formed on the other divided lower surface portion also reliably It can contact | abut to the to-be-contacted surface part of a bottom wall part. Therefore, the cutting insert 201 is stably fixed to the insert mounting seat.

  In addition, description of the tool main body of the cutting tool of 3rd Embodiment is abbreviate | omitted. The insert mounting seat of the tool body of the third embodiment also has the same characteristics as the insert mounting seat of the tool body of the first embodiment.

  Next, a fourth embodiment of the present invention will be described. The cutting insert 301 of 4th Embodiment is represented by FIGS. 28-32.

  The cutting insert 301 has a 90 ° rotationally symmetric shape with respect to the central axis of the through hole, and includes four large divided lower surface portions 3a, 3b, 3c, and 3d disposed at the corners of the lower surface 3, and a large divided lower surface. A total of eight divided lower surface portions including four small divided lower surface portions 3e, 3f, 3g, and 3h arranged between the portions are provided. These large divided lower surface portions and small divided lower surface portions are alternately arranged around the axis A. Therefore, the four large divided lower surface portions are arranged away from each other.

  The four large divided lower surface portions 3a, 3b, 3c, and 3d correspond to the divided lower surface portions in the first to third embodiments. Accordingly, each of the four large divided lower surface portions 3a, 3b, 3c, and 3d is also predetermined with respect to the plane F that is defined so that the central axis A is orthogonal to the predetermined lower surface portion in the first embodiment. Has a slope of. Then, each of the four large divided lower surface portions 3a, 3b, 3c, 3d crosses the large divided lower surface portion, and on the plane determined to include the central axis A, the upper surface 2 It is inclined with respect to the plane F so as to incline to the side. Further, these four large divided lower surface portions 3a, 3b, 3c, and 3d are related to each other such that four planes that are defined so as to extend them intersect at substantially one point on the central axis A.

  Of these divided lower surface portions 3a to 3h, the protruding portions are formed only on the small divided lower surface portions. The surfaces extending on the extended surface of the large divided lower surface portion 3a are the protruding end surface portion 7ga of the protruding portion 7g formed on the small divided lower surface portion 3g and the protruding end surface portion of the protruding portion 7h formed on the small divided lower surface portion 3h. 7 ha.

  The surfaces extending on the extended surface of the large divided lower surface portion 3b are the protrusion end surface portion 7hb of the protrusion portion 7h formed on the small divided lower surface portion 3h and the protrusion end surface portion of the protrusion portion 7e formed on the small divided lower surface portion 3e. 7 eb. Further, the surface extending on the extended surface of the large divided lower surface portion 3c is a protrusion end surface portion 7fc of the protruding portion 7f formed on the small divided lower surface portion 3f and the protrusion of the protruding portion 7e formed on the small divided lower surface portion 3e. This is the end face portion 7ec. Furthermore, the surface extending on the extended surface of the large divided lower surface portion 3d is a protrusion end surface portion 7fd of the protruding portion 7f formed on the small divided lower surface portion 3f and the protrusion of the protruding portion 7g formed on the small divided lower surface portion 3g. It is an end face part 7gd.

  The cutting insert of the fourth embodiment having such a configuration is also stably attached to the insert mounting seat of the tool main body of a cutting tool (not shown and not described). The insert mounting seat of the tool body of the fourth embodiment has the same characteristics as the insert mounting seat of the tool body of the first embodiment.

  As mentioned above, although several embodiment was demonstrated to the example about the cutting insert and blade-tip-exchange-type cutting tool of this invention, embodiment of this invention is not limited to said thing.

  For example, in the first embodiment and the second embodiment, the divided upper surface portion and the divided lower surface portion in the downward direction are parallel to each other, but their extended surfaces are planes orthogonal to the central axis A at different angles. You may cross F. For example, a cutting insert having a shape in which the inclination angle of the divided upper surface portion with respect to the plane F is θ1 and the inclination angle of the divided lower surface portion with respect to the plane F is θ2 smaller than θ1 is allowed in the present invention. Naturally, a cutting insert that reverses the magnitude relationship between the angle θ1 and the angle θ2 is also allowed.

  The cutting insert of the above-described embodiment is not particularly provided with a chip breaker, but may be provided. By forming the chip breaker on the upper surface, advantageous effects such as improvement of chip dischargeability and promotion of appropriate curling of chips can be expected.

  Moreover, not only the said notch part and step part but a recessed part or a convex part may be provided in the side surface of the cutting insert, and the convex part or recessed part engaged with it may be provided in the side wall part of an insert mounting seat. Their engagement can enhance the fixation of the cutting insert to the insert mounting seat. When providing the concavo-convex portions, the fastening force can be increased by forming them into a tapered shape.

  Further, regarding the screw hole formed in the insert mounting seat, the screw hole is directly formed in the bottom wall portion of the insert mounting seat in the above-described embodiment. However, unlike this, a female threaded protrusion with an internal thread formed on the inside is formed obliquely with respect to the bottom wall of the insert mounting seat, and the female threaded protrusion is fitted into the through hole of the cutting insert. Such a form is also possible. At that time, the effect of preventing rotation of the cutting insert 1 can be enhanced by making the cross-sectional shapes of the female threaded protrusion and the through hole not a circle but a polygon such as a triangle or a quadrangle.

  Moreover, you may form the long concave groove extended in the thickness direction of a cutting insert with respect to the side surface of a cutting insert, and may provide the convex part for fitting in the concave groove in the side wall of an insert mounting seat. Thereby, the detent effect of the cutting insert can be enhanced. In addition, the ditch | groove formed in the side surface which does not face the side wall part of insert mounting seat can also exhibit the effect as a nick. In addition, when the cutting insert is circular, the concave groove can be utilized as a means for positioning.

  The present invention can be applied not only to the rolling tool as in the above embodiment, but also to other types of cutting tools such as a turning tool and a drilling tool.

  Although the present invention has been described with a certain degree of specificity in the above-described embodiment and its modifications, the present invention is not limited to the above-described embodiment. It should be understood that various changes and modifications can be made to the present invention without departing from the spirit and scope of the claimed invention. That is, the present invention includes all modifications, applications, and equivalents included in the concept of the present invention defined by the claims.

Claims (14)

A through-hole extending through the first end surface and the second end surface substantially opposite to the first end surface, the center axis being defined;
A plurality of cutting blades disposed in a rotationally symmetrical manner with respect to the central axis line at an intersecting ridge line portion between the first end surface and the peripheral side surface extending between the first end surface and the second end surface;
A plurality of divided surface portions disposed rotationally symmetrically with respect to the central axis on the second end surface, each divided surface portion being associated with one of the plurality of cutting edges, and the center A plurality of divided surface portions formed so as to have a predetermined inclination with respect to a plane determined so that the axes are orthogonal to each other;
A cutting insert comprising a plurality of protrusions on the second end surface.   Each division surface part is formed so that it may incline to the 1st end face side as it leaves | separates from the said center axis line on the plane defined so that the said division axis part and the said center axis line may be included. The cutting insert according to 1.   3. The cutting insert according to claim 2, wherein the plurality of dividing surface portions are formed so as to extend along each of a plurality of planes defined to intersect with each other at approximately one point on the central axis. A cutting insert that is detachably attached to the insert mounting seat of the tool body using screws,
A through-hole extending through the first end surface and the second end surface substantially opposite to the first end surface, the center axis being defined;
A plurality of cutting blades disposed in a rotationally symmetrical manner with respect to the central axis line at an intersecting ridge line portion between the first end surface and the peripheral side surface extending between the first end surface and the second end surface;
A plurality of divided surface portions disposed rotationally symmetrically with respect to the central axis on the second end surface, each divided surface portion being associated with one of the plurality of cutting edges, and the center A plurality of divided surface portions formed so as to have a predetermined inclination with respect to a plane determined so that the axes are orthogonal to each other;
The number of the divided surface portions is equal to the number of the cutting edges,
When the cutting insert is attached to the insert mounting seat,
The divided surface portion related to the cutting edge to be enabled is a contacted surface portion in which a screw hole into which the screw in the insert mounting seat is screwed is arranged, and the screw hole is in contact with the contacted portion. Abutting against the abutted surface portion arranged obliquely with respect to the surface portion;
The cutting insert in which the inclination angle of the divided surface portion with respect to the plane corresponds to the inclination angle of the screw hole with respect to the contacted surface portion.   The cutting insert according to claim 4, wherein the second end surface further includes a plurality of protrusions. Each of the plurality of divided surface portions is formed substantially flat,
Each of the plurality of protrusions further includes at least one protrusion end surface;
Each protrusion end face portion is formed so as to extend on a plane defined to extend the division surface portion which is implicated, cutting insert according to any one of claims 1 to 3, 5. Comprising the three divided surface portions,
Each of the three divided surface portions is provided with one protrusion.
Each protrusion includes two protrusion end surfaces,
The cutting insert according to claim 6, wherein each projection end surface portion is associated with a division surface portion different from the division surface portion provided with the projection portion having the projection end surface portion. Comprising the two split surface portions,
Each of the two divided surface portions is provided with two protrusions,
Each protrusion includes one protrusion end surface,
The cutting insert according to claim 6, wherein each projection end surface portion is associated with a division surface portion different from the division surface portion provided with the projection portion having the projection end surface portion. The two divided surface portions are arranged to form a substantially V shape,
The two projecting portions provided on one of the two divided surface portions are arranged to face the two projecting portions provided on the other of the two divided surface portions. Item 9. The cutting insert according to Item 8. Comprising four of the dividing surface portions,
The four divided surface portions are disposed away from each other while at least one protrusion is disposed between the adjacent divided surface portions.
Each cutting surface part is a cutting insert of Claim 6 related with the projection part of the both sides of the dividing surface part arrange | positioned on the opposite side on both sides of the said center axis line.   The cutting insert is attached to the insert mounting seat by screwing a screw into a screw hole of the insert mounting seat of the tool body through the through hole of the cutting insert so that one of the plurality of cutting blades can be used. When attached, the divided surface portion related to the cutting edge to be usable comes into contact with the abutted surface portion of the insert mounting seat, and the hole axis of the screw hole of the insert mounting seat and the through hole The cutting insert according to any one of claims 1 to 3, and 5 to 10, wherein the plurality of dividing surface portions are formed so as to be parallel to the central axis. A cutting edge exchangeable cutting tool comprising a tool body having at least one insert mounting seat, wherein the cutting insert according to claim 4 is detachably mounted on the insert mounting seat,
The insert mounting seat is
When the cutting insert is attached to the insert mounting seat to enable use of one of the plurality of cutting edges, the split surface portion associated with the cutting edge to be enabled is A to-be-contacted surface part to be in contact;
When the cutting insert is attached to the insert mounting seat so that one of the plurality of cutting edges can be used, a hole axis extending so as to be parallel to the central axis of the through hole is provided. A cutting tool with a defined screw hole. A cutting-blade exchangeable cutting tool comprising a tool body having at least one insert mounting seat, to which the cutting insert according to any one of claims 1 to 3, and 5 to 11 is detachably mounted. Because
The insert mounting seat is
When the cutting insert is attached to the insert mounting seat to enable use of one of the plurality of cutting edges, the split surface portion associated with the cutting edge to be enabled is A to-be-contacted surface part to be in contact;
When the cutting insert is attached to the insert mounting seat so that one of the plurality of cutting edges can be used, a hole axis extending so as to be parallel to the central axis of the through hole is provided. Screw holes defined,
When the cutting insert is attached to the insert mounting seat so that one of the plurality of cutting edges can be used, each one of the plurality of protrusions is accommodated. Comprising at least one indentation,
Cutting tools. Each of the plurality of protrusions further includes at least one protrusion end surface;
When the cutting insert is attached to the insert mounting seat, at least one protrusion end surface portion formed so as to extend on a plane defined to extend the divided surface portion that contacts the contacted surface portion. The cutting tool according to claim 13, which is in contact with the abutted surface portion.

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