WO2015030183A1

WO2015030183A1 - Cutting insert and cutting edge-replaceable cutting tool

Info

Publication number: WO2015030183A1
Application number: PCT/JP2014/072760
Authority: WO
Inventors: 潤大塚
Original assignee: 株式会社タンガロイ
Priority date: 2013-08-30
Filing date: 2014-08-29
Publication date: 2015-03-05
Also published as: JP2016187836A

Abstract

A cutting insert in an embodiment of the present invention relates to a cutting tool for machining a narrow groove. Said cutting insert is equipped with an insert body and multiple protrusions. The insert body is equipped with a body upper surface, a body bottom surface, and a body side surface that extends therebetween, and has a mounting hole that has an axis and penetrates through the body upper surface and body bottom surface. The protrusions, each having a cutting edge, are integrally formed with the insert body at outer positions of the insert body in directions orthogonal to the axis. The body lower surface is positioned closer to the body upper surface than the bottom surface of the protrusions in a direction parallel to the axis. As a result, the thickness of the insert body can be made thinner the protrusions, and the thickness of the bottom wall surface of an insert-mounting seat that comes into contact with the insert body can be increased. Consequently, a screw can be screwed with sufficient length into a screw hole of the bottom wall surface through the mounting hole.

Description

Cutting insert and cutting edge exchangeable cutting tool

The present invention relates to a cutting insert and a cutting edge exchangeable cutting tool to which the cutting insert is attached. More specifically, the present invention relates to a vertically installed cutting insert used for grooving and a side cutter to which the cutting insert is detachably attached to an insert mounting seat of a tool body.

Conventionally, as a cutting tool for grooving, there is a replaceable side cutter. An example of such a side cutter is disclosed in Patent Document 1. The cutting insert used for the side cutter described in Patent Document 1 includes a vertical surface provided with an upper surface having a substantially polygonal outline, a lower surface having an outline substantially matching the upper surface, and a side surface connecting the upper surface and the lower surface. It is a stand type. The cutting insert shown in Patent Document 1 has a substantially polygonal outline in a plan view of each of the upper surface and the lower surface, and is formed so as to protrude outward at the top or side of the polygon. It has a plurality of protrusions. More specifically, the cutting insert of one embodiment of Patent Document 1 has a substantially triangular shape in plan view on the upper surface side, and has three protrusions at positions corresponding to the tops of the triangles. Yes. A corner R surface is formed at the intersection between the upper surface of the protruding portion and the side end surface located on the outermost side in the protruding portion. Two cutting edges are formed along both edges of the corner R surface of one protrusion. The length of the intersecting portion where the corner R surface is formed is shorter than the diameter of the inscribed circle defined with respect to the body portion of the cutting insert excluding the protruding portion in plan view on the upper surface side.

With such a configuration, in the cutting insert described in Patent Document 1, the length of the intersection where the corner R surface is formed is shortened to a desired length without reducing the size of the entire cutting insert. Can do. Therefore, it is possible to easily set the rake angle in the radial direction to the positive side without reducing the rigidity of the cutting insert. Further, since the cutting insert has no limitation on the size of the curved shape (for example, the radius of curvature of its cross section) of the corner R surface provided at the intersection, the corner R has a shape corresponding to the corner curved surface to be formed in the groove. It also has the advantage that the surface can be designed freely.

International Publication No. 2012/173255

By the way, in the groove processing, it is necessary to form grooves of various sizes according to the purpose. In particular, in recent years, there is a demand for a tool capable of forming a very narrow groove having a groove width of 6 mm or less.

Here, in order to apply the cutting insert described in Patent Document 1 to a grooving process (specifically, a groove width of 6 mm or less) having a contour shape as it is and having a narrower groove width, according to the groove width. It is necessary to reduce the thickness of the cutting insert. In the side cutter of Patent Document 1, cutting inserts are arranged vertically with respect to each of both end faces of a substantially disk-shaped tool body. Therefore, when the cutting insert is mounted on the side cutter, the length of the cutting edge (that is, the cutting edge that cuts the bottom of the groove) located on the outer peripheral surface of the side cutter is substantially the same as the thickness of the cutting insert. Therefore, in order to ensure a constant cutting edge length, a constant thickness must be maintained for the cutting insert. That is, when considering the case where grooves are formed by mounting cutting inserts on both end faces of the side cutter, the cutting edge length by one cutting insert needs to be at least larger than half of the groove width to be processed. is there. Therefore, the cutting insert itself also requires at least a length greater than half the width of the groove to be machined, that is, a thickness greater than half the width of the side cutter. For this reason, the thickness of the support wall surface (that is, the bottom wall surface) of the portion (insert mounting seat) where the cutting insert is mounted in the side cutter becomes thinner than half of the groove width to be processed. For example, when the groove width is 6 mm, the wall surface of the insert mounting seat of the side cutter is less than 3 mm even at the maximum thickness. Thus, when the thickness of the wall surface of the insert mounting seat becomes extremely thin, when the cutting insert is mounted on the insert mounting seat with the mounting screw, the “hanging portion” (or screw hole) of the mounting screw in the insert mounting seat. Length) becomes too short, and the fixing force of the cutting insert becomes weak. Furthermore, since the tip of the mounting screw is not allowed to protrude from the screw hole to the back side of the insert mounting seat, the “hanging portion” of the mounting screw is further shorter than the screw hole length, so the fixing force of the cutting insert is much weaker. Become. Therefore, the possibility that the cutting insert is displaced due to a certain amount of cutting resistance applied to the cutting insert during machining increases. Such misalignment of the cutting insert may cause chipping of the cutting edge. Further, since the thickness of the support wall surface of the insert mounting seat is thin, the rigidity of the side cutter itself tends to decrease. The reduction in rigidity of the tool itself is a major cause of chattering.

The present invention has been made in view of the above circumstances, and it can be used for groove processing with a relatively narrow width, but it can be used as a cutting insert having high fixability to an insert mounting seat and it can be freely attached and detached. It aims at providing the cutting tool with which it is mounted | worn.

According to the first aspect of the present invention,
An insert body part, comprising: an upper surface of the body part; a lower surface of the body part facing the upper surface of the body part; and a side surface of the body part extending between the upper surface of the body part and the lower surface of the body part. An insert body portion having an attachment hole having an axis passing through the upper surface and the lower surface of the body portion;
A plurality of protrusions, each having a cutting edge, each provided integrally with the insert body part at an outer position of the insert body part in a direction perpendicular to the axis. And
The protrusion includes an upper surface of the protrusion disposed on the upper surface side of the body part, a lower surface of the protrusion disposed on the lower surface side of the body part, two protrusion side surfaces connected to the corresponding body part side surfaces, and A protrusion-side end surface extending between the corners, and a corner R surface extending between the upper surface of the protrusion and the end-side end surface of the protrusion is formed on the protrusion.
The cutting edge has a corner cutting edge formed along an edge of the corner R surface, and the protrusion upper surface, the corner R surface, and the protrusion so that the side surface of the protrusion becomes a rake face. It is formed along the crossed ridge line portion between the side end surface and the protruding portion side surface,
The lower surface of the body part is located on the upper surface side of the body part with respect to the lower surface of the protruding part in a direction parallel to the axis.
A cutting insert is provided.

The lower surface of the body part may extend to the side surface of the body part. Further, the lower surface of the body part may extend substantially perpendicular to the axis of the mounting hole. The upper surface of the body part and the upper surface of the protruding part can be formed to extend along the same plane that is substantially perpendicular to the axis of the mounting hole. Alternatively, the upper surface of the body part and the upper surface of the protruding part may have an insert inner angle of less than 180 °, in which case the upper surface of the body part extends substantially perpendicular to the axis of the mounting hole, and the upper surface of the protruding part is the upper surface of the body part It is possible to extend away from the extended surface. The upper surface of the body part and the upper surface of the protruding part are preferably connected without a step. A chamfered portion or a concave portion may be formed along the intersection ridge line portion between the upper surface of the body part and the side surface of the body part. When the upper surface of the cutting insert is regarded as a polygonal shape, the protruding portion may be formed so as to be located at a position corresponding to the top of the polygon. For example, the upper surface of the cutting insert has a substantially triangular shape. In this case, the cutting insert can comprise three protrusions.

The present invention also exists in a cutting tool. The cutting tool which concerns on the 2nd aspect of this invention is a cutting tool provided with the tool body which has an at least 1 insert mounting seat, and the cutting insert of the said 1st aspect is detachably mounted in this insert mounting seat. Preferably, when the cutting insert is attached to the insert attachment seat, the insert attachment seat has one wall surface in contact with the body side surface of the cutting insert, and the other wall surface or walls are the body portion. It is configured so as to be in contact with any one of the lower surface and the lower surface of the protruding portion, and to have no other mutual contact. The insert mounting seat may include a bottom wall surface and at least two side wall surfaces that are substantially perpendicular to the bottom wall surface. The bottom wall surface includes a first bottom wall surface portion in which a screw hole for fixing the cutting insert is formed, and a second bottom wall surface portion formed in a position recessed from the first bottom wall surface portion. In addition, the second bottom wall surface portion may be provided around the first bottom wall surface portion so as to correspond to the position of the protruding portion of the cutting insert. The side wall surface may include a first side wall surface portion connected to the first bottom wall surface portion and a second side wall surface portion connected to the second bottom wall surface portion.

According to the cutting insert of the first aspect of the present invention, the lower surface of the body part is located on the upper surface side of the body part with respect to the lower surface of the protruding part in the direction parallel to the axis of the mounting hole. Therefore, since the insert body portion is configured to be thinner than the protruding portion, the “hanging portion” of the mounting screw in the insert mounting seat of the tool body is ensured longer than the thickness in the direction parallel to the axis of the protruding portion. be able to. Therefore, even in the case of a relatively thin cutting insert, it is possible to greatly suppress a decrease in the fixing property of the cutting insert with respect to the tool body. Therefore, according to the first aspect of the present invention, it is possible to remarkably reduce chatter, breakage of the cutting edge, and the like due to a decrease in cutting insert fixability.

FIG. 1 shows a top perspective view of a cutting insert according to an embodiment of the present invention. FIG. 2 shows a top view of the cutting insert of FIG. FIG. 3 shows a bottom view of the cutting insert of FIG. 4 shows a side view of the cutting insert of FIG. 5 shows a bottom perspective view of the cutting insert of FIG. FIG. 6 shows a cross-sectional view of the cutting insert of FIG. 1 along the line VI-VI in FIG. FIG. 7 shows a perspective view of a blade-tip-exchangeable cutting tool equipped with the cutting insert of FIG. 1 according to one embodiment of the present invention. FIG. 8 shows a perspective view of a tool body in the cutting tool of FIG. FIG. 9 shows an enlarged perspective view of one insert mounting seat of the tool body of FIG. 8 and the vicinity thereof. FIG. 10 is a perspective view showing a state in which the cutting insert of FIG. 1 is mounted on the insert mounting seat of FIG. FIG. 11 is an enlarged view of one cutting insert of the cutting tool of FIG. 7 and the vicinity thereof. FIG. 12 is a schematic cross-sectional view taken along the line XII-XII in FIG. 11, and is an explanatory diagram exaggeratingly showing the relationship between the cutting insert and the tool body. 13 is a cross-sectional view of a cutting insert and a cutting tool according to another embodiment of the present invention, and shows a cross-sectional view at a position corresponding to the line XII-XII of FIG.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

As shown in FIGS. 1 to 6, the cutting insert 1 of the present embodiment includes an upper surface 2 and a lower surface 3 that face each other or are opposite to each other, and a peripheral side surface 4 that extends therebetween. With. The upper surface 2 and the lower surface 3 are substantially parallel. An axis A passing through the upper surface 2 and the lower surface 3 can be defined in the cutting insert 1. The cutting insert 1 is shaped to be substantially 120 ° rotationally symmetrical around this axis A. A mounting hole 5 having a central axis A that coincides with the axis A is formed so as to penetrate the upper surface 2 and the lower surface 3.

The cutting insert 1 includes an insert body portion 6 and three projecting portions 7 provided integrally with the insert body portion 6. The insert body part 6 includes a body part upper surface 8, a body part lower surface 9, and three body part side surfaces 10 extending therebetween. The body part upper surface 8 and the body part lower surface 9 face each other or are positioned on the opposite side with respect to each other and are substantially parallel to each other. Therefore, the body part upper surface 8 and the body part lower surface 9 extend substantially perpendicular to the axis A. One protrusion 7 is disposed between any two side surfaces of the three body side surfaces 10. In addition, the part remove | excluding the three protrusion parts 7 from the cutting insert 1 can be defined as the insert body part 6. FIG.

The insert body portion 6 is designed so as to substantially have a 120 ° rotationally symmetric shape around the axis A, that is, the center axis A of the mounting hole 5. Similarly, three protrusions 7 are arranged at rotationally symmetrical positions around the axis A. Therefore, the three protrusions 7 are arranged at equal intervals in the circumferential direction around the axis A. Thus, the cutting insert 1 is formed so as to have a shape that is rotationally symmetric about 120 ° around the axis A substantially as a whole. Further, in this cutting insert 1, when a plane is defined so as to include the axis A and divide each protrusion 7 into two equal parts, each protrusion 7 is formed to be bilaterally symmetric with respect to this plane. . As an example, this plane is a plane along line VI-VI in FIG. The line VI-VI in FIG. 2 corresponds to a first plane that includes the axis A and extends so as to bisect the one protrusion 7 located on the upper side in FIG. Note that, as shown in FIGS. 1 and 2, marks M <b> 1 and M <b> 2 are provided on the upper surface 2 so as to make it easy to identify the position of a cutting edge described later. However, different marks may be used in the same place or different places, or such identification marks may not be used.

When the upper surface 2 of the cutting insert 1 is regarded as a triangular shape (when the body upper surface 8 (or the body lower surface 9) of the insert body 6 is regarded as a substantially triangular shape or a triangular shape), it corresponds to the top of the triangle. The three protrusions 7 are positioned so as to be positioned. The protruding portion 7 is provided at an outer position of the insert body portion 6 in the direction orthogonal to the axis A. That is, the protruding portion 7 is provided so as to protrude or extend outward from the insert body portion 6.

The three protrusions 7 are independent from each other and have substantially the same configuration. Therefore, unless otherwise specified, any one protrusion 7 will be described below.

The protruding portion 7 is provided at an outer position of the insert body portion 6 in a direction orthogonal to the axis A. The protrusion 7 has a substantially rectangular parallelepiped shape (substantially block shape). Specifically, the protrusion 7 includes a protrusion upper surface 11, a protrusion lower surface 12, two protrusion side surfaces 13, and a protrusion-side end surface 14. The protruding part upper surface 11 is located on the body part upper surface 8 side and is connected to the body part upper surface 8. The projecting portion lower surface 12 is located on the body portion lower surface 9 side, and is located a certain distance away from the body portion lower surface 9 in the insert thickness direction (direction parallel to the axis A). Therefore, the protrusion part 7 protrudes on the lower surface side in the insert thickness direction on the basis of the insert body part 6. Each of the two protrusion side surfaces 13 is connected to the corresponding body side surface 10. The protruding portion side end surface 14 extends between the protruding portion upper surface 11, the protruding portion lower surface 12, and the two protruding portion side surfaces 13. Further, a corner R surface (corner curved surface) 15 extending between the protrusion upper surface 11 and the protrusion-side end surface 14 is formed on the protrusion 7 from one side to the other of the two protrusion side surfaces 13. ing. The corner R surface 15 is directly connected to each of the protrusion upper surface 11, the two opposing protrusion side surfaces 13, and the protrusion-side end surface 14. The corner R surface 15 and the protruding portion side end surface 14 formed in this way include the axis A and the protruding portion 7 as can be understood from the protruding portion 7 having a substantially rectangular parallelepiped shape in each protruding portion 7. Is extended in a direction orthogonal to a plane (for example, the first plane) defined to bisect.

In the present embodiment, the upper surface 11 of the protruding portion is formed on substantially the same plane as the upper surface 8 of the body portion. However, as is apparent from the sectional view of FIG. It is in a position protruding one step in a direction parallel to the axis A rather than 9. That is, the upper surface 11 of the protruding portion is substantially flush with the upper surface 8 of the body portion, while the lower surface 9 of the body portion is closer to the upper surface 11 of the protruding portion in the direction parallel to the axis A than the lower surface 12 of the protruding portion. Is formed. In other words, the insert body portion 6 is formed so as to be thinner than the protruding portion 7 in the insert thickness direction parallel to the axis A. As a result, a recessed space so as to be surrounded by the protrusion 7 is substantially formed between the body lower surface 9 and the three protrusions 7 on the lower surface 3 side. Moreover, in this embodiment, although the protrusion part 7 is formed so that it may have the same thickness altogether, it is not limited to this, The inside of the insert body part 6 from the protrusion part side end surface 14 side It may be formed so that the thickness gradually decreases as it moves away to the side (mounting hole 5 side), and finally becomes the same as the thickness of the insert body portion 6. Alternatively, instead of gradually decreasing the thickness, the protruding portion 7 may be formed so that the thickness gradually decreases. Here, the protrusion upper surface 11 and the body upper surface 8 are “substantially” in the same plane. In the side view of the cutting insert 1 and the cross-sectional view of FIG. This is because the connection is made at a slight angle so that the insert inner angle α is less than 180 °. This means that the protrusion upper surface 11 extends away from the extension surface E of the body upper surface 8 shown in FIG. 6 as the distance from the body upper surface 8 increases. Thus, the structure which the protrusion part upper surface 11 and the body part upper surface 8 connect with a fixed angle may be sufficient, and you may exist on the same plane completely.

As described above, on the lower surface 3 side, the body portion lower surface 9 is not flush with the protruding portion lower surface 12. Therefore, on the lower surface 3, a step surface 18 (see FIG. 5) is formed so as to connect the body portion lower surface 9 and the protruding portion lower surface 12. The step surface 18 may be included in a part of the protrusion 7. The step surface 18 is configured as a substantially concave curved surface portion that is smooth to some extent. The step surface 18 is formed in consideration of the stress concentration between the lower surface 9 of the body part and the lower surface 12 of the projecting portion and the mounting property of the cutting insert to the insert mounting seat described later.

As shown in FIG. 2, for each corner R surface 15, the maximum dimension sandwiching both ends (both corners) at the intersections with the protruding side surfaces 13 on both sides is defined as the length L of the corner R surface 15. To do. The length L of the corner R surface 15 is set within a predetermined range. In the cutting insert 1, an inscribed circle IC can be defined with respect to the body part upper surface 8 of the insert body part 6 as shown in FIG. 2. When the cutting insert 1 is viewed from the side facing the upper surface 2 along the axis A (that is, FIG. 2), the inscribed circle IC is an insert in which the protruding portion 7 is not connected to the upper surface 2 of the cutting insert 1. It may be determined so as to be inscribed in the edge region of the body portion 6. The length L of the corner R surface 15 is shorter than the diameter of the inscribed circle IC. Accordingly, the length L of the corner R surface 15 is sufficiently shorter than the size of the insert body portion 6. The length L of the corner R surface 15 is preferably equal to or greater than the thickness T of the protrusion 7. By doing in this way, the rigidity of the protrusion part 7 can be raised suitably, aiming at size reduction of the protrusion part 7. FIG.

In the one protrusion 7, the cutting edge 16 is formed for each of the two protrusion side surfaces 13, and thus two cutting edges 16 are formed. The cutting edge 16 has a corner cutting edge 16 a formed along the edge of the corner R surface 15. And the cutting edge 16 is formed along the intersection ridgeline part of each of the protrusion part upper surface 11, the corner | angular R surface 15, and the protrusion part side end surface 14, and the protrusion part side surface 13 so that the protrusion part side surface 13 may become a rake face. Has been. The curved shape of the corner cutting edge 16a, for example, the curvature or the radius of curvature thereof, can be appropriately changed according to the size of the corner curved surface of the groove desired to be formed in the work material. One cutting edge 16 in one protrusion 7 is a right-handed cutting edge, and the other cutting edge 16 is a left-handed cutting edge. Therefore, in the cutting insert 1, the three cutting edges 16 can be used as a right-handed cutting edge, and another three cutting edges 16 can be used as a left-handed cutting edge. Thus, the cutting insert 1 is an indexable cutting insert. The right-handed cutting edge means that the protrusion upper surface 11 is the right side when the cutting insert 1 is viewed from the direction of the blade edge, that is, the direction facing the protrusion side surface 13 and the protrusion side end face 14 is viewed upward. The left-handed cutting edge is a cutting edge on the left side when the cutting insert 1 is viewed from the direction of the cutting edge. In this way, with respect to each cutting edge 16, the protruding portion side surface 13 can be configured to function as a rake face, and the protruding portion upper surface 11, the protruding portion side end surface 14, and the corner R surface 15 are respectively flank surfaces. It is configured to be able to function as.

Further, in the present embodiment, a concave portion 17 is formed along the entire length of the intersection ridge line portion (intersection portion) between the body upper surface 8 and the body side surface 10. That is, the thickness of the insert body portion 6 is thinner than the other portions along the intersecting ridge line portion between the body portion upper surface 8 and the body portion side surface 10. In the cutting insert 1 of the present embodiment, the concave portion 17 is formed in a stepped shape as shown in FIG. 6, but is not limited to this, and other parts such as a chamfer cut obliquely are used. It may be a shape.

Furthermore, in this embodiment, the body part side surface 10 has the upper surface side part 10a and the lower surface side part 10b. The upper surface side portion 10a protrudes outward in the direction perpendicular to the axis A as compared with the lower surface side portion 10b. Therefore, the upper surface side portion 10a of the body part side surface 10 can particularly function as a contact surface during attachment to an insert mounting seat described later. A recess 10c extends from the upper surface side to the lower surface side at the approximate center of the upper surface portion 10a.

The vicinity of the cutting edge of the cutting insert 1 can be made of a hard material such as cemented carbide, coated cemented carbide, cermet, ceramic, or ultra-high pressure sintered body containing diamond or cubic boron nitride.

The cutting insert 1 having such a configuration is detachably mounted on a tool body 21 of a cutting tool 20 that is a side cutter, as shown in FIG.

The tool body 21 has a substantially disk shape, and as shown in FIG. 8, two end faces 22 (including the back side face in FIG. 8), and an outer peripheral face 23 extending between the two end faces 22. It is basically composed of a bore hole 24 penetrating the center of the two end faces 22. The two end faces 22 face each other, that is, are located on the opposite sides of each other, and each has a substantially circular shape. A plurality of pairs of chip pockets 25 and insert mounting seats 26 are formed on the outer peripheral surface 23. The chip pocket 25 is provided so as to suitably discharge chips. The insert mounting seat 26 is provided on the outer peripheral surface 23 on the rear side in the tool rotation direction K adjacent to the corresponding chip pocket 25. The insert mounting seats 26 are alternately formed in a staggered pattern on each of the two end faces 22 of the tool body 21, and the plurality of cutting inserts 1 are alternately mounted in a staggered pattern on each of the two end faces 22. At this time, the cutting insert 1 is vertically mounted on the insert mounting seat 26 so that a corner cutting edge of a usable cutting edge protrudes outward. When the cutting insert 1 is attached, the protruding portion side end surface 14 of the protruding portion 7 of the cutting insert 1 slightly protrudes from the outer peripheral surface 23 of the tool body 21, and the corner R surface 15 of the protruding portion 7 is positioned outside. ing. In the present embodiment, the insert mounting seat 26 is configured so that the cutting insert 1 is mounted at an axial rake of −3 ° and a radial rake of −7 °. However, the axial rake and the radial rake are large. This is not limited to this. By setting the axial rake and the radial rake in this way, the working cutting edge 16 of the cutting insert 1 is provided with a positive clearance angle with respect to the tool radial direction and the tool rotating shaft 21A direction.

In the tool body 21, an insert mounting seat 26 is formed for each of the two end faces 22. The insert mounting seat 26 for one of the two end faces 22 is configured for a right-handed cutting edge, and the insert mounting seat 26 for the other is configured for a left-handed cutting blade. The insert mounting seat 26 for the right-handed cutting edge and the insert mounting seat 26 for the left-handed cutting edge are left and right with respect to a plane (not shown) defined to be orthogonal to the tool rotation axis 21A and extend between the two end faces 22. Symmetric.

As shown in the enlarged view of FIG. 9, the insert mounting seat 26 includes a bottom wall surface 27 and a side wall surface 28 that extends in a direction intersecting the bottom wall surface 27, and in particular, here is a substantially right angle. The bottom wall surface 27 includes a first bottom wall surface portion 27a in which a screw hole 30 for screwing an attachment screw 29 for fixing the cutting insert 1 is formed, and a position lower than the first bottom wall surface portion 27a (that is, The second bottom wall surface portion 27b is formed basically at a position recessed from the first bottom wall surface portion 27a. The three second bottom wall surface portions 27b are provided so as to correspond to the positional relationship of the protrusions 7 of the cutting insert 1, and the first bottom wall surface portion 27a is centered on the screw hole 30 of the first bottom wall surface portion 27a. It is arranged around. The three second bottom wall surface portions 27b are formed so as to suitably accommodate the corresponding protruding portions 7, and are different from each other in order to put the cutting insert 1 into a use state. The side wall surface 28 includes a first side wall surface portion 28a directly connected to the first bottom wall surface portion 27a and a second side wall surface portion 28b directly connected to the second bottom wall surface portion 27b. It is configured to be continuous. In addition, a recessed part (soaking part) may be provided between the 1st bottom wall surface part 27a and the 1st side wall surface part 28a, and a recessed part is similarly provided between the 2nd bottom wall surface part 27b and the 2nd side wall surface part 28b. It may be provided.

10, the cutting insert 1 is fixed to the insert mounting seat 26. That is, the projecting portions 7 of the cutting insert 1 are arranged so as to correspond to the second bottom wall surface portions 27b of the insert mounting seats 26, respectively. At this time, the body side surface 10 of the cutting insert 1 and the first side wall surface portion 28a of the insert mounting seat 26 are in contact, but the protruding portion 7 is not in contact with the second side wall surface portion 28b (FIGS. 10 and 11). reference). That is, the second side wall surface portion 28 b is formed so as not to come into contact with the protruding portion side surface 13 and the protruding portion side end surface 14. This prevents the cutting edge 6 that has not been used from being damaged by coming into contact with the insert mounting seat 26. Further, the step surface 18 (see FIGS. 5 and 6) of the protrusion 7 of the cutting insert 1 extends so as to connect the first bottom wall surface portion 27a and the second bottom wall surface portion 27b of the insert mounting seat 26. ) No contact with the stepped wall surface 31. That is, the first bottom wall surface portion 27a is in a plan view (viewed from the direction parallel to the axis of the screw hole 30) of the first bottom wall surface portion 27a than the outer shape of the inside of the projecting portion lower surface 12 of the cutting insert 1. It is formed to have a small width. Therefore, when the cutting insert 1 is disposed on the insert mounting seat 26, the first bottom wall surface portion 27a extends away from the inside so as to be surrounded by the three protruding portions 7. Thereby, the peripheral side surface 4 of the cutting insert 1 is in contact with only the two first side wall surface portions 28a in the tool radial direction, that is, substantially adjacent to each other via one second side wall surface portion 28b. It is supported only by the two first side wall surface portions 28a. Therefore, even if some distortion or the like occurs due to manufacturing errors or the like in the cutting insert 1 or the insert mounting seat 26, the cutting insert 1 can be more firmly fixed without rattling in the insert mounting seat 26b.

Further, in this embodiment, when the cutting insert 1 is attached to the insert attachment seat 26, the body portion lower surface 9 is in contact with the first bottom wall surface portion 27a as schematically shown in FIG. The projecting portion lower surface 12 does not contact the second bottom wall surface portion 27b. That is, the difference in the height direction (in the insert thickness direction) between the body bottom surface 9 and the protrusion bottom surface 12 is the screw hole between the first bottom wall surface portion 27a and the second bottom wall surface portion 27b. The cutting insert 1 and the insert mounting seat 26 are configured to be smaller than the difference in the height direction (which is a direction parallel to the 30 axis). Accordingly, the lower surface of the cutting insert 1 is in contact with only the first bottom wall surface portion 27a, that is, only the body lower surface 9 of the cutting insert 1 is used as a seating surface, and the lower surface 3 of the cutting insert is formed only by the first bottom wall surface portion 27a. Will be supported. Therefore, even if some distortion or the like occurs due to manufacturing errors or the like in the cutting insert 1 or the insert mounting seat 26, the cutting insert 1 can be reliably fixed without rattling. 12 exaggerates only the contact state between the surface of the cutting insert 1 and the wall surface of the insert mounting seat 26. In FIG. 12, the inclination of the cutting insert in the insert mounting seat, their dimensions, etc. are not necessarily shown. Not accurate.

Thus, in the present embodiment, the lower surface side of the cutting insert 1 is configured to support it only with the lower body surface 9. However, conversely, a configuration in which the cutting insert 1 is supported on the lower surface side by contact with only the lower surface 12 of the projecting portion is also possible. Such another embodiment is described with reference to FIG. However, unlike FIG. 12, the cutting insert 1 ′ and the cutting tool described in FIG. 13, which is not a schematic diagram, have the same configuration as the cutting insert 1 and the cutting tool 20 except for those described here. In FIG. 13, the protrusion lower surface 12 of the cutting insert 1 ′ is in contact with the second bottom wall surface portion 27b, but the body lower surface 9 is not in contact with the first bottom wall surface portion 27a. In other words, in the present invention, on the lower surface side of the cutting insert, the fixing property of the cutting insert can be improved by supporting the cutting insert on either the body lower surface 9 or the protruding lower surface 12. However, the present invention does not exclude a form in which both the body lower surface 9 and the protruding lower surface 12 are in contact with the bottom wall surface 27 of the insert mounting seat 26.

The operation and effect of the cutting insert 1 and the cutting tool 20 described above will be described.

First, in the cutting insert 1, the insert body portion 6 and the protruding portion 7 are integrally provided as described above, and the protruding portion has the shape and the size. Therefore, when the cutting insert 1 is placed vertically on the tool body 21 as described above, the radial rake angle of the cutting edge 16 formed on the protruding portion 7 can be easily set to the positive side. This is because, for one thing, the length of the corner R surface 15 of the protrusion is smaller than the size of the cutting insert. Another reason is that, in such an attached state, the protruding portion side end face 14 does not protrude outward in the tool radial direction, so that a clearance angle can be easily secured.

Furthermore, in the said embodiment of this invention, since the body part lower surface 9 is formed in the position close | similar to the body part upper surface 8 side rather than the protrusion part lower surface 12, the "hanging part" of the attachment screw 29 in the tool body 21 Can be made relatively long. That is, in the cutting insert 1, the insert body part 6 is formed thinner than the projecting part 7 from the side of the body part lower surface 9, so that the first bottom wall surface of the insert mounting seat 26 of the tool body 21 is thinned. The portion 27a can be made thicker in the direction parallel to the axis of the screw hole 30 than the second bottom wall surface portion 27b. Therefore, since the screw hole 30 can be deepened by the amount that the thickness of the first bottom wall surface portion 27a is increased, the “hanging portion” of the mounting screw 29 can be made longer. As a result, even if the entire thickness of the cutting insert is reduced in order to process a groove with a very narrow width, it is possible to ensure a large “hanging portion”, that is, an engageable portion in the insert mounting seat 26 of the mounting screw 29. Can do. Therefore, the effect that the fall of the fixability of the cutting insert 1 is suppressed can be acquired. At this time, since it is not necessary to reduce the thickness of the protruding portion 7 for the purpose of improving the fixability of the cutting insert 1, the protruding portion 7 is formed at the intersecting ridge line portion of the protruding portion side surface 13 and the protruding portion side end surface 14. The cutting blade 16 has a necessary length. Therefore, the cutting edge length required for mounting the cutting inserts 1 on both sides of the tool body 21 in a zigzag manner and performing grooving, that is, a length larger than at least half of the groove width to be machined (tool body) The thickness of the protrusions, which is greater than half the thickness of 21, remains maintained at the cutting edge 16 of the cutting insert 1.

Further, since the first bottom wall surface portion 27a formed to be relatively thick is directly connected to the first side wall surface portion 28a that is a part of the side wall surface 28, the rigidity of the entire insert mounting seat 26 is improved. There is an effect. That is, the first bottom wall surface portion 27a formed thick is not provided independently, but is directly connected to a part of the side wall surface 28 so that the entire bottom wall surface 27 is twisted. The insert mounting seat 26 is remarkably strong against a large distortion. In particular, the rigidity around the screw hole 30 that is generally fragile in strength can be greatly improved. Therefore, since the effect of suppressing the decrease in seating stability of the cutting insert 1 and the occurrence of chatter due to the distortion of the tool body 21 itself due to the low rigidity can be obtained, the accuracy of the groove to be formed is improved. As described above, the present invention can exert a particularly great effect in the side cutter using the vertical type cutting insert in which the thickness of the insert mounting seat is extremely thin.

Moreover, in the cutting insert 1, although the body part upper surface 8 and the protrusion part upper surface 11 are substantially on the same plane, it is not limited to this, The body part upper surface 8 protrudes in the axis A direction. It may be formed so as to be lower than the part upper surface 11 (that is, a step is formed between the body part upper surface 8 and the protruding part upper surface 11). However, if there is such a step, the “hanging portion” of the mounting screw 29 becomes smaller by the step, or the insert body portion 6 becomes thinner by the step. Therefore, in order to maximize the thickness of the “hanging portion” of the mounting screw 29 and the insert body portion 6, it is preferable that the body portion upper surface 8 and the protruding portion upper surface 11 are connected without a step.

Furthermore, in the insert body part 6, it is preferable to provide a recessed part 17 that is recessed in the thickness direction along the entire length of the intersecting ridge line part between the body part upper surface 8 and the body part side surface 10. This is because it is possible to greatly suppress the phenomenon that chips generated by cutting work are caught in the gap between the body side surface 10 and the side processed surface of the work material. The reason is as follows. In cutting with a tool using the cutting insert 1 adapted for grooving with a groove width of 6 mm or less, chips having a small size are generated as compared with a case where this is not the case. On the other hand, as described above, the cutting insert 1 is disposed on the tool body with a predetermined axial rake and a predetermined radial rake in order to ensure a positive clearance angle. That is, the cutting insert 1 is disposed in a positional relationship that is inclined at a constant angle with respect to the end surface 22 and the outer peripheral surface 23 of the tool body 21. Therefore, between the cross ridge line part of the body part upper surface 8 and the body part side surface 10 that is located in front of the tool rotation direction K of the working cutting edge 16, and the side machining surface of the work material, Narrow “wedge-shaped” gaps inevitably occur. Since the wedge-shaped gap is narrow as described above, when the chip is large, the possibility that the chip enters the chip is low. However, small chips may enter the gap and get caught in the narrowest part of the wedge shape. As described above, when chips are bitten between the cutting insert and the work material, the surface of the work material may be damaged by the chips. On the other hand, when the recessed part 17 is provided in the intersection ridgeline part of the body part upper surface 8 and the body part side surface 10, the space between the intersection ridgeline part and the side part machining surface of the work material is widened, and the wedge shape Even the narrowest part is large enough not to bite chips. That is, by increasing the gap between the cutting insert 1 and the work material, the cutting insert 1 is configured so that even if chips enter the gap, they are easily separated from the outside without being bitten. Thus, since the biting of small chips can be suppressed by providing the concave portion 17, the surface roughness of the surface of the work material is improved.

In the above-described embodiment and its modifications, the present invention has been described with a certain degree of specificity, but 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

The body part upper surface (8), the body part lower surface (9) facing the body part upper surface (8), the body part upper surface (8) and the body part lower surface (9). And a body part side surface (10) extending between the body part upper surface (8) and the body part lower surface (9) and having an attachment hole (5) having an axis (A). The insert body (6),
A plurality of protrusions (7), each having a cutting edge (16), each at an outer position of the insert body part (6) in a direction perpendicular to the axis (A). A plurality of protrusions (7) provided integrally with (6),
The protrusion (7) includes a protrusion upper surface (11) disposed on the body upper surface (8) side, and a protrusion lower surface (12) disposed on the body lower surface (9) side. It has two protrusion side surfaces (13) connected to the corresponding body side surface (10), and a protrusion side end surface (14) extending therebetween, and the protrusion (7) includes the protrusion A corner R surface (15) extending between the top surface (11) and the protruding portion side end surface (14) is formed;
The cutting edge (16) has a corner cutting edge formed along an edge of the corner R surface (15), and the protrusion upper surface so that the protrusion side surface (13) is a rake face. (11), the corner R surface (15) and the projecting portion side end surface (14), and the projecting portion side surface (13) is formed along the intersecting ridge line portion,
The lower surface (9) of the body part is positioned closer to the upper surface (8) of the body part than the lower surface of the protrusion (12) in a direction parallel to the axis (A).
Cutting insert (1).
The cutting insert (1) according to claim 1, wherein the body part lower surface (9) extends to the body part side surface (13).
The cutting insert (1) according to claim 1 or 2, wherein the upper surface (8) of the body part and the upper surface (11) of the protruding part are connected without a step.
The chamfered part or the recessed part (17) is formed in the intersection ridgeline part of the said body part upper surface (8) and the said body part side surface (10) along this intersection ridgeline part. The cutting insert (1) according to claim 1.
The protrusion (7) is formed so as to be located at a position corresponding to the top of the polygon when the upper surface (2) of the cutting insert (1) is regarded as a polygon. Cutting insert (1) as described in any one of 1-4.
The upper surface (2) of the cutting insert (1) has a substantially triangular shape and includes the three protrusions.
Cutting insert (1) according to claim 5.
A cutting tool (20) comprising a tool body (21) having at least one insert mounting seat (26), wherein a cutting insert is detachably mounted on the insert mounting seat (26),
The cutting insert is a cutting insert (1) according to any one of claims 1 to 6,
Cutting tool (20).
When the cutting insert (1) is attached to the insert mounting seat (26), the insert mounting seat (26) includes the body part side surface (10) of the cutting insert (1) and the body part lower surface ( The cutting tool (20) according to claim 7, wherein the cutting tool (20) is configured to contact only one of 9) and the lower surface (12) of the protruding portion.
The insert mounting seat (26) includes a bottom wall surface (27) and a side wall surface (28) substantially perpendicular to the bottom wall surface (27),
The bottom wall surface (27) is recessed more than the first bottom wall surface portion (27a) in which a screw hole (30) for fixing the cutting insert (1) is formed, and the first bottom wall surface portion (27a). And a second bottom wall surface portion (27b) formed at the position, and the second bottom wall surface portion (27b) is located at the position of the protrusion (7) of the cutting insert (1). It is provided around the first bottom wall surface portion (27a) so as to correspond,
The side wall surface (28) includes a first side wall surface portion (28a) connected to the first bottom wall surface portion (27a) and a second side wall surface portion connected to the second bottom wall surface portion (27b) ( 28b),
Cutting tool (20) according to claim 7 or 8.