JPWO2013031926A1 - Cutting insert - Google Patents

Abstract

The present invention relates to a cutting insert having a cutting edge (7) formed at an intersecting ridge line portion between one end surface (2) of two opposing end surfaces and a side surface (9) extending between the two end surfaces ( Regarding 1). The cutting insert (1) of one embodiment is a concave curved blade portion (7a) constituting a part of the cutting blade (7), and has a concave curved blade portion curved in a direction connecting two end faces. A concave curved surface (11) is formed on one end surface (2) so as to extend to the concave curved blade portion (7a). The concave curved surface (11) includes a rake surface portion (11a), a first rising wall surface portion (11c), and a second rising wall surface portion formed at a position farther from the other end surface than the first rising wall surface portion. (11e) is included.

Description

  The present invention relates to a cutting insert used for a blade-tip replaceable cutting tool, and more particularly to a cutting insert mainly used for a blade-tip replaceable drill.

  Conventional cutting inserts have a cutting edge shape intended to generate chips that are curved in the width direction (direction perpendicular to the longitudinal direction) rather than in the longitudinal direction (direction along the chip discharge direction). There is a cutting insert. Chips curved in the width direction that can be generated by using such a cutting insert are easy to break or are prevented from being excessively elongated in a spiral shape.

  As a cutting insert aiming at such an effect, there is a cutting insert as shown in Patent Document 1, for example. The cutting insert of Patent Document 1 is for a drill for drilling a hole. In this drill, as the insert on the outer peripheral side so that the rotation trajectory of each cutting edge intersects the tip of the tool body, As the side insert, the two cutting inserts are detachably mounted in different arrangements. This cutting insert has a cutting edge portion with a recess when used as a cutting insert on the outer peripheral side, and a cutting edge portion without a recess when used as a cutting insert on the center side. It is designed in consideration of the ease of elongation and breakage. When this cutting insert is used as a cutting insert on the outer peripheral side, the cutting edge portion has a substantially corrugated shape due to the presence of the recess, which can contribute to the generation of chips curved in the width direction.

Japanese Patent No. 3652045

  Chips having a curved cross-sectional shape, as represented by chips generated by using the cutting insert of Patent Document 1, are certainly weak in the force in the width direction, and only a relatively small force is applied. Break. However, since this chip has a trough and a peak extending in the longitudinal direction, the chip tends to be strong against bending in the longitudinal direction. Such a tendency is generally higher in a chip having a portion curved in the width direction than in a chip having no portion curved in the width direction.

  When the bending strength in the longitudinal direction of the chip increases, the frequency of the extended chip extending straight without being substantially deformed and vigorously colliding with the wall surface of the chip breaker of the cutting insert increases. When the chips repeatedly vigorously collide with the wall surface of the chip breaker, the wear of the wall surface of the chip breaker proceeds faster. The part where the chip breaker wears is the part on the track where the chip extends. Therefore, if it wears out, the chip breaker will not be able to apply sufficient force to the chip, or will not be able to apply force in the appropriate direction, so chip breaking etc. will not be performed smoothly, for example Chips are easily clogged.

  The present invention has been developed in view of the above problems. That is, an object of the present invention is to provide a cutting insert having a structure that reduces the impact force applied to the chip breaker by chips extending in the longitudinal direction and suppresses wear of the chip breaker.

  The cutting insert of 1 aspect of this invention is a cutting edge formed in the crossing ridgeline part of one end surface and side surface of two end surfaces, the side surface extended between two end surfaces, and two end surfaces It is related with the cutting insert which has. This cutting insert is a concave curved blade part that constitutes a part of the cutting edge, and has a concave curved blade part that curves in a direction connecting two end faces, and one end face that extends to the concave curved blade part. A rake face portion adjacent to the concave curved blade portion, a first rising wall surface portion, and the first rising wall surface, which are sequentially arranged in a direction away from the concave curved blade portion. And a concave curved surface including a second rising wall surface portion formed at a position farther from the other end surface of the two end surfaces than the portion.

  According to the cutting insert having such a configuration, the chip extending along one end face of the cutting insert is first lifted from below by the first rising wall surface portion formed on the cutting edge side, and the chip You can change the course. After that, the chip collides with the second rising wall surface formed at a position farther from the cutting edge than the first rising wall surface and away from the other end surface, so that the second rising wall surface The part applies a force to the chip, which can promote the breaking of the chip. Thus, according to the cutting insert which concerns on 1 aspect of this invention, the course of a chip is first deflected by the 1st standing | starting-up wall surface part arrange | positioned at the cutting-blade side, and a chip is the 2nd 2nd chip. Direct hitting on the rising wall surface portion can be prevented, thereby suppressing wear of the second rising wall surface portion.

  Preferably, the second rising wall surface portion of the concave curved surface extends so as to form a curved surface that is recessed in a direction away from the concave curved blade portion side. The chip breaking ability is further enhanced by the combined action of this structure and the above configuration. That is, when the second rising wall surface portion is a concave curved surface, that is, a concave curved surface, the direction in which the second rising wall surface portion applies a breaking force to the chips is not one direction but multidirectional. Therefore, chips are more easily broken.

  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 perspective view of a cutting insert according to an embodiment of the present invention. FIG. 2 is a plan view of the cutting insert of FIG. FIG. 3 is a front view of the cutting insert of FIG. FIG. 4 is a right side view of the cutting insert of FIG. FIG. 5 is a cross-sectional view taken along line VV of the cutting insert of FIG. 6 is a partially enlarged view of a portion of the cutting insert shown in FIG. 5 surrounded by a circle VI. 7 is a cross-sectional view of the cutting insert of FIG. 2 taken along the line VII-VII. FIG. 8 is a partially enlarged view of a portion surrounded by a circle VIII of the cutting insert of FIG. FIG. 9 is a side view of a blade tip replaceable drill, which is a cutting tool according to an embodiment of the present invention. FIG. 10 is a side view of the drill of FIG. 9 when the cutting insert of FIG. 1 is mounted. 11 is a bottom plan view when the cutting insert of FIG. 1 is mounted on the drill of FIG. FIG. 12 is an enlarged assembly view of the cutting edge replaceable drill provided with the cutting insert of FIG. 1, and is a view when the cutting insert of FIG. 1 is used as a cutting insert on the outer peripheral side. FIG. 13 is an enlarged assembly view of the cutting edge replaceable drill provided with the cutting insert of FIG. 1, and is a view when the cutting insert of FIG. 1 is used as a center side cutting insert. FIG. 14A is a schematic diagram illustrating a basic shape of a cutting insert according to another embodiment of the present invention. FIG. 14B is a schematic diagram illustrating a basic shape of a cutting insert according to still another embodiment of the present invention. FIG. 14C is a schematic diagram illustrating a basic shape of a cutting insert according to still another embodiment of the present invention. FIG. 14D is a schematic diagram illustrating a basic shape of a cutting insert according to still another embodiment of the present invention. FIG. 15A is a schematic diagram illustrating a shape of a cutting edge of a cutting insert according to still another embodiment of the present invention. FIG. 15B is a schematic diagram illustrating a shape of a cutting edge of a cutting insert according to still another embodiment of the present invention. FIG. 16 is a schematic diagram showing the shape of the cutting edge of a cutting insert according to still another embodiment of the present invention. FIG. 17 is a schematic diagram showing the shape of the cutting edge of a cutting insert according to still another embodiment of the present invention. FIG. 18 is a schematic diagram showing the shape of the cutting edge of a cutting insert according to still another embodiment of the present invention. FIG. 19 is a schematic diagram showing the shape of the cutting edge of a cutting insert according to still another embodiment of the present invention.

  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, an embodiment of the present invention will be described with reference to FIGS. In these figures, lines representing surface boundaries, curved shapes, etc. are positively represented to facilitate understanding of the structure and / or features of cutting inserts and cutting tools according to one embodiment of the present invention. .

  A cutting insert 1 according to an embodiment of the present invention is shown in FIGS. The cutting insert 1 has two end faces 2, 3 that are opposite, ie opposite to each other, and a peripheral side face 4 that extends between these end faces 2, 3. A through hole 5 penetrating between the two end surfaces 2 and 3 is formed in the cutting insert 1, and a central axis A extending so as to pass through the two end surfaces 2 and 3 is defined in the through hole 5. The through hole 5 is positioned at the substantial center of each of the end faces 2 and 3. A fastener such as a screw is inserted through the through-hole 5, and the cutting insert 1 is fixed to an insert mounting seat of the tool body as will be described later, and can function as a blade portion of a cutting edge exchangeable cutting tool. In the cutting insert 1, the two end faces 2, 3 are formed substantially in parallel as a whole, and extend along a plane determined to be orthogonal to the central axis A.

  As shown in FIG. 2, when the cutting insert 1 according to the present embodiment is viewed in plan (when the cutting insert 1 is viewed from the side facing the one end surface 12), the outer surface of the end surface is surrounded by a parallelogram imaginary line J. It is. That is, the cutting insert 1 is a plate-like body whose basic shape is a parallelogram, and is 180 ° rotationally symmetric with respect to the central axis A. In this embodiment and the present invention, the “basic shape of the cutting insert” is formed when the outline shape of the cutting insert of the present embodiment and the present invention is roughly surrounded by a minimum number of straight lines. A simple polygonal shape. In other words, the basic shape is simpler and more intuitive when one end surface is viewed in plan, ignoring the fine curved shape of the edge of this one end surface, especially the fine curved shape of the cutting edge. Refers to the shape.

  In the following description, for convenience, one end surface 2 depicted in FIG. 2 is referred to as an “upper surface”, and the other end surface 3 opposite to the upper surface 2 is referred to as a “lower surface”. However, this is not intended to limit the invention. In the following description, “upper” refers to a direction away from the cutting insert 1 in the direction of the axis A with respect to the upper surface 2, for example, and “lower” refers to, for example, the axis A from the cutting insert 1 with respect to the lower surface 3. The direction away in the direction of. In the following description, “height” refers to one end surface or a plane parallel to the end surface, particularly preferably a plane determined to be orthogonal to the axis A, and preferably in the direction of the axis A. It is a specified length.

  In the cutting insert 1, a cutting edge 6 is formed at an intersecting ridge line portion between the upper surface 2 and the peripheral side surface 4. Here, the cutting insert 1 is a positive type insert. That is, as shown in FIGS. 3 and 4, the upper surface 2 and the peripheral side surface 4 are substantially at an angle of less than 90 degrees. Therefore, the cutting insert 1 is suitable for forming a positive clearance angle. The lower surface 3 is configured to function as a seating surface for the insert mounting seat, and is formed as a substantially flat surface in the present embodiment. However, the lower surface 3 as the seating surface is not limited to being flat, and can be formed to have various shapes corresponding to the corresponding surfaces of the insert mounting seat.

  However, when the cutting insert 1 is a negative type insert, both of the two end surfaces 2 and 3 can be the upper surface, both of which can be the lower surface, and there is a cutting edge at each edge of both end surfaces. Can be formed. Therefore, when the cutting insert 1 is such a negative type cutting insert, the configuration on the upper surface side described below can be applied to both end surfaces. In this case, the two end surfaces are formed so as to function as seating surfaces for the insert mounting seats.

  In the cutting insert 1, two types of cutting edges 7 and 8 are formed as the cutting edge 6 at the intersecting ridge line portion between the upper surface 2 and the peripheral side surface 4 whose basic shape is a parallelogram. In the cutting insert 1, the two types of cutting edges 7 and 8 are alternately continuous, but may not be continuous.

  Since the upper surface 2 has a parallelogram as a basic shape, the peripheral side surface 4 has substantially four side surface groups (hereinafter simply referred to as “side surfaces”). The four side surfaces are two opposing first sides 9 that are opposite to each other and two opposing second sides 10 that are opposite to each other. The first side surface 9 and the second side surface 10 are alternately continuous.

  A first cutting edge 7 is formed at the intersecting ridge line portion between the first side surface 9 and the upper surface 2. A second cutting edge 8 is formed at the intersecting ridge line portion between the second side surface 10 and the upper surface 2. The first cutting edge 7 and the second cutting edge 8 are formed for different purposes. Therefore, as is apparent from FIGS. 1 and 2, the first cutting edge 7 and the second cutting edge 8 are formed to have a unique curved shape, and the upper surface 2 and the peripheral side surface 4 are Sides 9, 10 are shaped. In the cutting insert 1, the first and second cutting edges 7 and 8 are shaped to have tip portions 7L and 8L, respectively.

  As shown in FIGS. 9 to 11, the cutting insert 1 includes a cutting insert 1 ′ on the outer peripheral side and a cutting insert 1 ″ on the central side so that the rotation trajectories of the cutting edges intersect with the tip of the tool body. It is formed so that any of the cutting inserts 1 ′, 1 ″ having different usage purposes can be used in the cutting edge exchange type cutting tool that is detachably mounted. The first cutting edge 7 is configured to function as an outer peripheral blade when the cutting insert 1 is used as an outer peripheral cutting insert 1 ′. On the other hand, the second cutting edge 8 is configured to function as a center blade when the cutting insert 1 is used as a center-side cutting insert 1 ″. Thus, the cutting insert 1 can be used as a cutting insert for an outer peripheral blade or a cutting insert for a central blade with a single cutting insert. As can be understood from FIG. 2, in the cutting insert 1, the first cutting edge 7 and the first side surface 9 appear to be shorter than the second cutting edge 8 and the second side surface 10 in a plan view of the cutting insert 1. Is associated with them. However, the present invention allows cutting inserts having these length relationships reversed.

  The cutting insert 1 is formed into a shape that is 180 ° rotationally symmetric with respect to the central axis A and is an indexable cutting insert. The pair of first cutting edges 7 are formed to have the same configuration, and the pair of second cutting edges 8 are formed to have the same configuration. The cutting blades formed to have the same configuration have the same or substantially the same configuration with respect to the upper surface 2 and the peripheral side surface 4. Therefore, in the following, the cutting insert 1 will be described with respect to any one cutting edge of the pair of first cutting edges and any one cutting edge of the pair of second cutting edges.

  With respect to the first cutting edge 7, a concave curved surface (hereinafter referred to as “first concave curved surface”) 11 is formed on the upper surface 2. Specifically, three first concave curved surfaces 11 are formed on the first cutting edge side as the outer peripheral edge with a space from each other. However, two concave curved surfaces (hereinafter referred to as “second concave curved surfaces”) 12 are also formed on the second cutting edge 8 side as the central blade with a space from each other.

  As shown in FIGS. 3 and 4, each concave curved surface 11, 12 is formed so as to extend to the edge of the upper surface 2 as if it were the first and second cutting edges 7, 8. Correspondingly, the first and second cutting edges 7 and 8 have concave curved blade portions that curve so as to be concave toward the lower surface 3 in the direction connecting the two end faces 2 and 3, that is, in the direction of the axis A. (Hereinafter referred to as “concave curved blades”) 7a and 8a are formed.

  Regarding the first cutting edge 7 side, as shown in FIGS. 1 to 3, the upper surface 2 has a convex curved surface, that is, a first convex curved surface (or first raised portion) adjacent to the first concave curved surface 11. 13 is formed. More specifically, the first convex curved surface 13 is disposed between the first concave curved surfaces 11, and is formed so that the end edge portion thereof and the end edge portion of the first concave curved surface 13 are smoothly and continuously connected. ing.

  Similarly to the first concave curved surface, the first convex curved surface 13 is formed to extend to the edge of the upper surface 2, that is, to the cutting edge 7. Corresponding to the formation of the first convex curved surface 13, the first cutting edge 7 swells upward, that is, a convex curved blade portion curved in a convex shape in the direction connecting the two end faces (hereinafter referred to as “convex”). 7b) is formed.

  In the cutting insert 1, since the first concave curved surface 11 and the first convex curved surface 13 that are curved in opposite directions are connected smoothly and continuously, the concave curved blade 7 a and the convex curved blade in the first cutting edge 7 are connected. 7b is also connected smoothly and continuously. Therefore, as shown in FIG. 3, when the cutting insert 1 is viewed from the side facing the first side surface 9, particularly when the cutting insert 1 is viewed from the side with respect to the first cutting edge 7, the first cutting edge 7, particularly its main part. Exhibits an almost wavy shape.

  Also on the second cutting edge 8 side, a convex curved surface corresponding to the first convex curved surface 13, that is, a second convex curved surface (or second raised portion) 14 is provided. The second convex curved surface 14 is disposed between the two second concave curved surfaces 12 and is formed so that the edge portion thereof and the edge portion of the second concave curved surface 12 are smoothly and continuously connected. The second convex curved surface 14 is also formed so as to extend to the edge of the upper surface 2, similarly to the second concave curved surface 12. Corresponding to the formation of the second convex curved surface 14 on the second cutting edge 8 side, a convex curved blade portion similar to the convex curved edge 7b, that is, the convex curved edge 8b is also formed on the second cutting edge 8. ing. Therefore, as shown in FIG. 4, when the cutting insert 1 is viewed from the side facing the second side face 10, particularly when the cutting insert 1 is viewed from the side with respect to the second cutting edge 8, the second cutting edge 8, particularly its main part. Exhibits an almost wavy shape.

  Regarding the first cutting edge 7 side configured to function as the outer peripheral edge of the cutting insert 1, the first concave curved surface 11 and the first convex curved surface 13 are respectively the concave curved blade 7 a and the convex of the first cutting edge 7. Extending to the curved blade 7b, one continuous curved surface 15 is formed. 5 and 6 are cross-sectional views taken along a plane that passes through the deepest portion of one first concave curved surface 11 on the first cutting edge 7 side and extends at right angles to the lower surface 3. 7 and 8 are cross-sectional views taken along a plane that passes through the top of one first convex curved surface 13 on the first cutting edge 7 side and extends at right angles to the lower surface 3. 5 to 8 are cross-sectional views taken along planes defined so as to extend substantially perpendicular to the cutting edge 7 and parallel to the axis A in the plan view of FIG.

  As shown in FIGS. 5 to 8, the curved surface 15 is adjacent to the rake face 16 (hereinafter referred to as “first rake face”) formed adjacent to the first cutting edge 7 and the first rake face 16. A second rake face (or dent face) 17 arranged in order from the first rake face side and a dent portion 15c having a first rising wall surface 18, and a top of the first rising wall surface 18, A connecting surface 19 that is gently inclined toward the lower surface 3 side and a second rising wall surface 20 connected to the connecting surface 19 are provided.

  Such a curved surface 15 is formed through each of the first concave curved surface 11 and the first convex curved surface 13. Accordingly, the first concave curved surface 11 is disposed adjacent to each other in order in a direction away from the first cutting edge 7, and is formed as a first rake face portion 11 a formed adjacent to the first cutting edge 7 and a hollow surface portion. A second rake face portion 11b, a first rising wall surface portion 11c, a connecting surface portion 11d, and a second rising wall surface portion 11e are provided (see FIG. 6). The 1st convex curved surface 13 is arrange | positioned adjacent to each other in order in the direction away from the 1st cutting edge 7, the 1st rake surface part 13a formed adjacent to the 1st cutting edge 7, and the 2nd as a hollow surface part. A rake face portion 13b, a first rising wall surface portion 13c, a connecting surface portion 13d, and a second rising wall surface portion 13e are provided (see FIG. 8). Therefore, the first rake surface 16 of the curved surface 15 includes the first rake surface portion 11 a of the first concave curved surface 11 and the first rake surface portion 13 a of the first convex curved surface 13. The second rake surface 17 of the curved surface 15 includes a second rake surface portion 11 b of the first concave curved surface 11 and a second rake surface portion 13 b of the first convex curved surface 13. The first rising wall surface 18 of the curved surface 15 includes a first rising wall surface portion 11 c of the first concave curved surface 11 and a first rising wall surface portion 13 c of the first convex curved surface 13. The connecting surface 19 of the curved surface 15 includes a connecting surface portion 11 d of the first concave curved surface 11 and a connecting surface portion 13 d of the first convex curved surface 13. The second rising wall surface 20 of the curved surface 15 includes a second rising wall surface portion 11 e of the first concave curved surface 11 and a second rising wall surface portion 13 e of the first convex curved surface 13. The first rake face 16 and the second rake face 17 are particularly related to the first cutting edge 7 when the cutting insert 1 is attached to the tool body and used as a cutting tool blade. By surface intended to function as a rake face.

  In the cutting insert 10 of the present embodiment, the first rake face 16 and the second rake face 17 are configured to form a rake face that is inclined downward toward the lower surface 3 side, that is, has a positive rake angle. ing. From FIG. 6, it can be seen that the first rake face 16 is formed substantially parallel to the lower surface 3, but it is understood from FIG. 8 that the first rake face 16 is inclined toward the lower surface 3 side. it can. Thus, the 1st rake face 16 is formed so that it may incline toward the lower surface 3 side when it sees as a whole. Moreover, the inclination angle with respect to a plane determined to be orthogonal to the axis A of the second rake face 17 that is a depression surface is larger than the same inclination angle of the first rake face 16, and the rake angle in the second rake face is the first. The first and second rake faces are formed so as to be larger than the rake angle in the rake face (see FIGS. 6 and 8).

  Of the curved surface 15, a portion adjacent to the first rake surface 16, in particular, the first rising wall surface 18 and the second rising wall surface 20 (see the CB portion in FIG. 2) is configured to function as a chip breaker. Yes.

  As the first rising wall surface 18 and the second rising wall surface 20 are separated from the cutting edge 7, the first rising wall surface 18 and the second rising wall surface 20 extend away from the lower surface 3, that is, so that the wall surface facing the cutting edge 7 side rises. Accordingly, the first rising wall surface 18 and the second rising wall surface 20 have inclinations opposite to those of the first rake face 16 and the second rake face 17 with respect to a plane determined to be orthogonal to the axis A, respectively. . The first rising wall surface 18 has a first rising slope that is determined so as to change the chip extending direction, that is, the flow direction. On the other hand, the second rising wall surface 20 has a second rising inclination determined so as to promote the cutting or breaking of the chips. The first rising slope and the second rising slope may be the same, but are different from each other here. In the cutting insert 1, the inclination angle θ <b> 2 of the second rising wall surface is larger than the inclination angle θ <b> 1 of the first rising wall surface with reference to the plane P defined to be orthogonal to the axis A (see FIGS. 6 and 8). ). This angular relationship is preferably determined on a plane determined so as to extend substantially perpendicular to the cutting edge 7 and parallel to the axis A in the plan view of FIG.

  The rising height h of the first rising wall surface 18 is higher than the portion 18 a farthest from the lower surface 3 in the axis A direction of the first rising wall surface 18, that is, the portion where the top portion intersects the extended surface E of the first rake face 16. It is designed to be at a high position (position farther from the lower surface 3 in the direction of the axis A) (see FIG. 6). That is, the height h of the first rising wall surface 18 is designed to be high enough that the top portion 18 a of the first rising wall surface 18 does not intersect with the extended surface of the first rake face 16. This is true for both the first rising wall surface portions 11c and 13c. That is, as shown in FIGS. 6 and 8, the extension surface E <b> 1 defined to extend the first rake surface portion 11 a of the first concave curved surface 11 intersects the portion excluding the edge portion of the first rising wall surface portion 11 c. As described above, the first and second rake face portions 11a and 11b and the first rising wall surface portion 11c of the first concave curved surface 11 are formed and extended to extend the first rake face portion 13a of the first convex curved surface 13. The first and second rake face portions 13a and 13b and the first rising wall surface portion 13c of the second convex curved surface 13 are formed so that the surface E2 intersects the portion excluding the edge portion of the first rising wall surface portion 13c. Yes. Referring to FIG. 6, the rising height h refers to the minimum portion 15 u of the hollow portion 15 c (corresponding to the cutting edge side edge portion of the first rising surface) to the top portion 18 a of the first rising wall surface 18. It can be defined by referring to the vertical distance (distance in the direction of the axis A). However, the rising height h is preferably determined on a plane determined so as to extend substantially perpendicular to the cutting edge 7 and parallel to the axis A in the plan view of FIG. The rising height h may be different at different locations on the curved surface 15.

  The second rising wall surface 20 has a portion farthest from the lower surface 3 in the direction of the axis A of the second rising wall surface 20, that is, its top portion 20 a is at least compared with the top portion 18 a and the first cutting edge 7 of the first rising wall surface 18. Thus, it is designed to be located at a position away from the lower surface 3 in the direction of the axis A. This configuration is clearly shown in the cross-sectional views in FIGS. 5 to 8 in a plane defined to extend substantially perpendicular to the cutting edge 7 and parallel to the axis A in plan view of the cutting insert 1. Yes.

  Note that the cross-sectional shape of the first concave curved surface 11 is not limited to the above-mentioned shape only at the deepest portion, and the shape of the first concave curved surface 11 is not limited to that shown in FIG. It has a shape feature as shown in FIG. In other words, the first concave curved surface 11 is slightly dimensionally different at each position regardless of where the first concave curved surface 11 is viewed in cross section, but at each position, the first rake surface portion, the second rake surface portion, the communication surface portion, 2 rising wall surfaces. The same applies to the first convex curved surface 13.

  As shown in FIGS. 1 and 2, particularly FIG. 1, the second rising wall surface portion 11 e of the first concave curved surface 11 is curved to be recessed in a direction away from the concave curved blade 7 a of the corresponding first cutting edge 7. It extends to form a surface. In other words, as shown in FIG. 2, when the second rising wall surface portion 11e corresponding to the first concave curved surface 11 is viewed in plan, the edge portion on the cutting edge side of the second rising wall surface portion is defined. The edge contour 11 f on the different side has a concave curve shape that curves toward the center of the upper surface 2 of the cutting insert 1.

  The second rising wall surface portion 11e of the first concave curved surface 11 will be described in more detail with a focus on the first concave curved surface 11 ′ through which the line mm shown in FIG. 2 passes. The second rising wall surface portion 11e of the first concave curved surface 11 ′ is located farthest from the corresponding concave curved blade 7a at a position located on a line mm passing through the deepest portion of the first concave curved surface 11 ′. A concave curved surface is formed that is bent into a V shape so as to approach the corresponding concave curved blade 7a as it goes away from the line mm. In other words, in the plan view of FIG. 2, the second rising wall surface portion 11 e has a shape that becomes tapered toward the center of the upper surface 2.

  On the other hand, the second rising wall surface portion 13e of the first convex curved surface 13 is extended so as to form a convex curved surface that curves toward the convex curved blade 7b of the corresponding first cutting edge 7, as shown in FIG. Exist. In other words, as shown in FIG. 2, when the second rising wall surface portion 13 e of the first convex curved surface 13 is viewed in plan, the side of the second rising wall surface portion is different from the edge on the cutting edge side. The edge contour 13 f has a convex curve shape that curves outwardly of the cutting insert 1.

  The second rising wall surface 13e of the first convex curved surface 13 will be described in more detail by focusing on the first convex curved surface 13 'through which the line nn in FIG. 2 passes. The second rising wall surface portion 13e of the first convex curved surface 13 ′ is a convex curved blade corresponding to a portion located on a line nn passing through a portion farthest from the lower surface 3 side of the first convex curved surface 13 ′, that is, the top portion. A convex curved surface bent in a V shape is formed so as to be the closest to 7b and away from the corresponding convex curved blade 7b as the distance from the line nn increases. That is, in the plan view of FIG. 2, the second rising wall surface portion 13 e of the first convex curved surface 13 has a V-shape opposite to the second rising wall surface portion 11 e of the first concave curved surface 11.

  Since the second rising wall surface portions 11e and 13e are designed as described above, the contour lines 11f and 13f of the second rising wall surface portion have a zigzag shape in plan view. Accordingly, the second rising wall surface 20 constitutes a wall surface extending in a sawtooth shape toward the first cutting edge 7 side.

  Also on the second cutting edge 8 side, similarly to the first cutting edge 7 side, the second concave curved surface 12 and the second convex curved surface 14 respectively extend to the second cutting edge 8 and have one continuous curved surface 22. Form. However, the degree of curvature of each of the second concave curved surface 12 and the second convex curved surface 14 on the second cutting edge 8 side is that of each of the first concave curved surface 11 and the first convex curved surface 13 on the first cutting edge 7 side. The degree of curvature of the second cutting edge 8 is smaller than the degree of curvature of the first cutting edge 7. As can be understood from FIGS. 1 and 2, the second concave curved surface 12 partially has the same configuration as the first concave curved surface 11, but particularly (corresponding to the second rising wall surface portion 11e). It is not formed so as to have two rising wall portions. The second convex curved surface 14 also has a configuration partially similar to that of the first convex curved surface 13, but is not particularly formed to have a second rising wall surface portion (corresponding to the second rising wall surface portion 13e). . This is because the curved surface 22 on the second cutting edge side is not particularly configured to function as a chip breaker, and is formed so that the second cutting edge functions as a central blade.

  However, the present invention allows the curved surface 22 on the second cutting edge side to be characterized and formed in the same manner as the curved surface 15 on the first cutting edge side. Alternatively, the second cutting edge may not be formed in a curved shape but may be formed in a substantially linear shape. In this case, the curved surface 22 on the second cutting edge side may be a flat surface.

  FIG. 9 is a side view of a blade tip replaceable drill 30 as a blade tip replaceable cutting tool according to an embodiment of the present invention. The drill 30 has a tool body 32 to which the cutting insert 1 is detachably mounted. In the drill 30 of FIG. 9, the cutting insert 1 is detachably attached to a tool body 32 as an outer peripheral cutting insert 1 ′ and the cutting insert 1 as a central cutting insert 1 ″.

  A central axis O is defined so as to extend in the longitudinal direction of the tool body 32, and the drill 30 is generally used by being rotated around the axis O. FIG. 10 is a perspective layout view of the cutting insert 1 as seen from the side of the tool body 32. In FIG. 10, the cutting insert 1 ′ as the outer peripheral side insert indicated by the dotted line is for showing the relationship between the locus of the outer peripheral side insert 1 ′ and the center side insert 1 ″, and the outer peripheral side indicated by the solid line. The cutting insert 1 ′ is represented by a position rotated by 180 ° with respect to the axis O.

  As shown in FIGS. 9 and 10, the two cutting inserts 1 have an outer surface side insert 1 ′ and a center side insert 1 ″ with the upper surface 2 facing the same rotational direction R on one tool body 32. Installed. That is, as shown in FIG. 11, the upper surface 2 of the outer peripheral cutting insert 1 ′ and the upper surface 2 of the central cutting insert 1 ″ are oriented in the opposite direction of approximately 180 °. Then, as shown in FIGS. 10 and 11, the two cutting inserts 1 are installed in the tool body 32 so that the rotation trajectories of the first cutting edge 7 on the outer peripheral side and the second cutting edge 8 on the center side intersect. . In addition, in FIG. 11, the processing hole H processed using the drill 30 with which the two cutting inserts 1 were mounted | worn with the tool main body 32 is represented by the dotted line.

  The tool body 32 has a spiral groove 34, a first insert mounting seat 36 for mounting the cutting insert 1 as a cutting insert 1 'on the outer peripheral side, and a cutting insert 1 "on the center side. And a second insert mounting seat 38 for mounting as described above. The first insert mounting seat 36 and the second insert mounting seat 38 are formed asymmetrically with respect to the rotation axis O of the tool body 32. One first insert mounting seat 36 is formed at a position farther from the rotation axis O than the other second insert mounting seat 38. As shown in FIG. 12, the cutting insert 1 is fixed to the first insert mounting seat 36 using a screw 40 that is a mechanical mounting means with the first cutting edge 7 facing the distal end side. As shown in FIG. 13, the cutting insert 1 is fixed to another second insert mounting seat 38 by using a screw 42 which is a mechanical mounting means in a state where the second cutting edge 8 is directed to the distal end side. . As shown in FIG. 10, in the cutting insert attached to the tool body 32, the tip portions 7 </ b> L and 8 </ b> L of the cutting blades 7 and 8 to be used are located on the most tip side of the tool body 32.

  The first insert mounting seat 36 is configured such that the lower surface 3 of the cutting insert 1 can be brought into contact with the bottom wall surface 36b having a screw hole 36a, and extends so as to rise from the bottom wall surface 36b so as to contact the side surface of the cutting insert 1. It has two side wall surfaces 36c and 36d that can be configured. Similarly, the second insert mounting seat 38 is configured such that the lower surface 3 of the cutting insert 1 can come into contact therewith, and has a bottom wall surface 38b having a screw hole 38a, and extends so as to rise from the bottom wall surface 38b, and is side surface of the cutting insert 1. And three side wall surfaces 38c, 38d, and 38e configured to be able to come into contact with each other.

  The operations and effects of the cutting insert 1 and the drill 30 described above will be described below.

  In the cutting insert 1 of this embodiment, since the 1st concave curved surface 11 and the 1st convex curved surface 13 are formed regarding the 1st cutting edge 7 as an outer peripheral blade, the 1st cutting edge 7 is the curve shape which exhibits a waveform shape. Have Due to such a cutting edge shape, the shape of the first cutting edge 7 is transferred to the chips generated by the cutting with the first cutting edge 7, and the chips can have a wavy shape.

  Chips generated by cutting using the first cutting edge 7 of the cutting insert 1 as a cutting edge first extend almost straight along the rake face, in particular the first rake face 16, toward the first rising wall face 18. Go ahead. Thereafter, the chip preferably collides with the first rising wall surface 18.

  The chips that have collided with the first rising wall surface 18 are changed in the flow direction, and once extend upward along the first rising wall surface 18, and thereafter, preferably in accordance with the shapes of the first rising wall surface 18 and the communication surface 19. Advances (extends) toward the center of the upper surface 2 of the cutting insert 1 while drawing a gentle curve. The chips collide with the second rising wall surface 20. Thereby, since the second rising wall surface 20 is curved and rises toward the first cutting edge 7 in the shape of the saw tooth as described above, the width direction of the chips without cutting from the second rising wall surface 20. The power is applied and the chips are broken. Since the chip when contacting the second rising wall surface 20 extends toward the upper side of the cutting insert 1 while drawing an arc, the component parallel to the second rising wall surface 20 of the chip speed increases. Accordingly, the component in the normal direction of the second rising wall surface 20 is reduced. As a result, the impact force received by the second rising wall surface 20 from the chip is weakened compared with the case where the chip hits the second rising wall surface directly, and wear of the second rising wall surface 20 is suppressed.

  As described above, the chips can collide with the first rising wall surface before colliding with the second rising wall surface 20. Since the first rising wall surface is designed to change the flow direction of the chip, the first rising wall surface 18 is also less susceptible to a large impact from the chip than the conventional chip breaker.

  In summary, the first rising wall surface 18 whose main purpose is to change the chip flow direction is disposed between the first cutting edge 7 and the second rising wall surface 20. Before the chip collides with the second rising wall surface and breaks, the first rising wall surface 18 can lift the chip from the lower side and divert the extending direction upward. Since the chip extending direction deviates upward, the impact when the chips contact the second rising wall surface 20 is weakened, and wear of the second rising wall surface 20 is suppressed.

  Furthermore, since the second rising wall surface portion 11e of the first concave curved surface 11 and the second rising wall surface 13e of the first convex curved surface 13 are curved as described above, each second rising wall surface 11e. , 13e can apply a breaking force to the chips from multiple directions. Therefore, according to the cutting insert 1, the chip breaking force is improved and the cutting performance is enhanced.

  Further, since the cutting insert 1 is formed so that the rake angle of the rake face 16 is positive and its extended surface intersects the first rising wall surface 18, chips generated by using the first cutting edge 7 are surely removed. It can collide with the first rising wall surface 18.

  As mentioned above, although one Embodiment of this invention was described, this invention is not limited only to said embodiment. In particular, at least one concave curved surface is formed on one end surface of the edge where the cutting edge is formed so that at least one concave curved blade is formed on the first cutting edge. A surface portion (corresponding to the first rake surface), a first rising wall surface portion, and a second rising wall surface portion, and the second rising wall surface portion faces away from the corresponding concave curved blade. Cutting inserts characterized by extending to form a concave curved surface are within the scope of the technical idea of the present invention.

  For example, the basic shape of the outer shape of the cutting insert is not limited to a parallelogram, but may be other shapes. 14A, 14B, 14C, and 14D show the basic outline of the outer shape of a cutting insert according to another embodiment of the present invention. 14A to 14D, the basic shape of the outline of the cutting insert can be a triangle, a rectangle, a square, a deformed hexagon, or the like.

  The recess of the chip breaker is not an essential component. A first rising wall surface may be formed directly directly on a rake face corresponding to the first rake face. However, it is preferable that a recess is formed to form the second rake face. In this case, since the contact area between the rake face including the first and second rake faces and the chip is reduced, the speed of rake face wear is reduced.

  The angle of the rake face is a rake face having a positive rake angle in the above embodiment, but may be a rake face having a negative rake angle. However, since the positive rake face can control the chip extending direction toward the lower surface side by the rake face, the chip can be reliably collided with the first rising wall surface. In this case, the curvature of the chip curl also increases. As the curvature of the chip curl increases, the contact force between the chip and the second rising wall surface tends to decrease.

  The chip breaker includes the first rising wall surface and the second rising wall surface. In the above embodiment, the chip breaker is positively formed only on the first cutting edge corresponding to the outer peripheral blade. However, it is also possible for chip breakers to be formed for all cutting edges. Moreover, all the cutting edges in the cutting insert may be formed so as to be able to function as outer peripheral blades, and for example, can be formed like the first cutting edge.

  Furthermore, based on the embodiments conceptually showing only a part of each of FIGS. 15A to 19, examples of the cutting edge shape of the first cutting edge having a shape different from the first cutting edge of the above embodiment will be described. FIG. 15A is a schematic diagram showing the shape of the first cutting edge 7 when a cutting insert according to another embodiment of the present invention is viewed from the side. As shown in FIG. 15A, the entire first cutting edge 7 can be composed of one concave curved blade portion 7a and a linear cutting blade portion 7c. The shape of the concave curved blade portion 7a is not a curved shape as shown in FIG. 15A, but may be a V shape as shown in FIG. 15B.

  FIG. 16 is a schematic diagram showing the shape of the first cutting edge 7 when a cutting insert according to another embodiment is viewed from the side. As shown in FIG. 16, in one first cutting edge 7, the concave curved blade portions 7a may be formed adjacent to each other.

  As in the embodiment shown in FIGS. 15 and 16, one or more concave curved blades can be formed with respect to one first cutting edge without forming the convex curved blade. In this case, the number of concave curved surfaces corresponding to the concave curved blades is formed on one end surface of the first cutting blade formed at the edge. When the plurality of concave curved blades are formed with respect to one first cutting blade, the plurality of concave curved blade portions may be continuous as in the embodiment of FIG. 16, but may be separated from each other. Thus, even with a cutting insert in which only at least one concave curved blade and the corresponding number of concave curved surfaces are formed with respect to one first cutting edge, the operations and effects described in the above embodiment are similarly achieved. . That is, even in cutting using such a cutting insert having a substantially corrugated first cutting edge, the path of the chip can be first deflected by at least one first rising wall surface portion constituting the first rising wall surface. . The chips whose course has been changed can collide with at least one second rising wall surface portion constituting the second rising wall surface. Therefore, chip breakage can be promoted while suppressing wear of the chip breaker including the second rising wall surface portion.

  FIG. 17 is a schematic diagram showing the shape of the first cutting edge when the cutting insert of still another embodiment is viewed from the side. In the embodiment shown in FIG. 17, a plurality of concave curved surfaces and concave curved blades 7 a are formed for one first cutting edge 7, and the depth of each concave curved surface is different. The “depth of the concave surface” refers to the length from the straight cutting edge 7c to the deepest part of the concave curved surface, that is, the concave curved blade 7a, in the direction of the axis A when viewed from the side. In addition, the “depth of the concave surface” when there is no linear cutting edge refers to the length from the flat surface (for example, the boss surface) of the upper surface to the deepest portion of the concave surface.

  Drawing 18 is a mimetic diagram showing the shape of the 1st cutting edge when the side view of the cutting insert of another embodiment is seen. Similarly to the embodiment shown in FIG. 17, the first cutting edge of the embodiment of FIG. 18 has a plurality of convex curved surfaces and convex curved blades 7b, and the height of each convex curved surface is different. The “height of the convex curved surface” refers to the length from the straight cutting edge 7c to the raised portion, that is, the top of the convex curved blade 7b in the direction of the axis A when viewed from the side.

  As described above, the depth of the plurality of concave curved surfaces in one cutting edge may be different. Moreover, the height of the several convex curved surface in one cutting edge may differ. Even when a plurality of concave curved blades and convex curved blades, that is, a concave curved surface and a convex curved surface, are formed with respect to one cutting edge, the depth of each concave curved surface does not have to be the same size. The heights of the curved surfaces need not all be the same size.

  FIG. 19 is an enlarged schematic view showing the shape of the first cutting edge when the cutting insert of still another embodiment is viewed from the side. In the embodiment shown in FIG. 19, the concave curved surface and the convex curved surface of one first cutting edge 7 are not continuous. Thus, the concave curved surface and the convex curved surface of one first cutting edge, that is, the concave curved blade 7a and the convex curved blade 7b may not be continuous.

  In general, as shown in FIG. 16 to FIG. 19, as the number of concave curved blades or convex curved blades in one cutting blade increases, that is, as the number of concave curved surfaces or convex curved surfaces increases, chips are more likely to be broken. . Further, chips are more easily broken when the concave curved blade and the convex curved blade are continuous than when the curved blade is not continuous.

  As described above, there are various cutting edge shapes within the scope of the technical idea of the present invention. Among them, the most effective in terms of the amount of reduction in the wear rate of the rising wall due to chips and the chip breaking property is that a plurality of concave curved surfaces and convex curved surfaces are alternated as in the first embodiment. It is the form which is connected smoothly and continuously, and the shape of the cutting edge when viewed from the side becomes a smooth corrugated shape.

  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 (13)

Two end faces (2, 3) facing each other, a side face (9) extending between the two end faces, and a cut formed at a cross ridge line portion between one end face of the two end faces and the side face A cutting insert (1) having a blade (7),
A concave curved blade portion (7a) which is a concave curved blade portion constituting a part of the cutting blade and which is curved in a direction connecting the two end faces;
A concave curved surface (11) formed on the one end surface so as to extend to the concave curved blade portion, adjacent to the concave curved blade portion, which is sequentially arranged in a direction away from the concave curved blade portion. The rake face portion (11a), the first rising wall surface portion (11c), and the second rising surface formed at a position farther from the other end surface of the two end surfaces than the first rising wall surface portion. A cutting insert (1) comprising a concave curved surface (11) including a wall surface portion (11e).   The second rising wall surface portion (11e) of the concave curved surface (11) extends so as to form a curved surface that is recessed in a direction away from the concave curved blade portion side. The cutting insert (1) according to 1.   The cutting insert (1) according to claim 1 or 2, wherein the cutting edge (7) has a plurality of concave curved blade portions, and the concave curved surface is formed with respect to each concave curved blade portion.   The cutting insert (1) according to claim 3, wherein the plurality of concave curved blade portions are spaced apart from one another.   In the concave curved surface (11), a recess surface portion (11b) that connects the rake surface portion (11a) and the first rising wall surface portion (11c) is further formed, and the extension is defined to extend the rake surface portion. The cutting insert (1) according to any one of claims 1 to 4, wherein the rake face portion, the recessed surface portion, and the first rising wall surface portion are formed such that a surface intersects the first rising wall surface portion. ). A convex curved blade portion (7b) constituting a part of the cutting edge, the convex curved blade portion (7b) curved in the direction connecting the two end faces;
A convex curved surface (13) formed on the one end surface so as to extend to the convex curved blade portion, the convex curved surface sequentially disposed in a direction away from the convex curved blade portion. A rake face portion (13a) adjacent to the blade portion, a first rising wall surface portion (13c), and a second rising wall surface portion formed at a position farther from the other end surface than the first rising wall surface portion. Cutting insert (1) according to any of claims 1 to 5, further comprising a convex curved surface (13) comprising (13e).   The second rising wall surface portion (13e) of the convex curved surface (13) extends so as to form a convex curved surface that curves toward the convex curved blade portion side. The cutting insert (1) described in 1.   The cutting insert (1) according to claim 6 or 7, wherein the cutting edge has a plurality of convex curved blade portions, and the convex curved surface is formed with respect to each convex curved blade portion.   In the convex curved surface, a recessed surface portion (13b) that connects the rake surface portion and the first rising wall surface portion is formed, and an extended surface that is defined to extend the rake surface portion is the first rising wall surface portion. The cutting insert (1) according to any one of claims 6 to 8, wherein the rake face part, the recessed face part, and the first rising wall face part are formed so as to intersect with each other.   The concave curved blade portion (7a) and the convex curved blade portion (7b) are continuously connected, and the concave curved surface (11) and the convex curved surface (13) are continuously connected. Cutting insert (1) according to any of claims 6 to 9.   The cutting insert (1) according to claim 10, wherein the concave curved blade portions and the convex curved blade portions are alternately and continuously connected. The cutting insert is a blade-tip replaceable drill (30) in which an outer peripheral cutting insert and a central cutting insert are detachably mounted so that the mutual rotation trajectory intersects the tip of the tool body (32), It can be used as a cutting insert on the outer peripheral side,
The cutting edge (7) is formed as a cutting edge in the outer peripheral cutting insert,
Cutting insert (1) according to any of the preceding claims.   The cutting insert (1) according to claim 12, wherein the cutting insert further comprises a second cutting edge (8) that functions when the cutting insert is used as the central cutting insert.

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