JP2019155558A - Cutting tool - Google Patents

Abstract

To achieve both of chip discharging performance when boring and chip processing performance in turning.SOLUTION: A cutting tool comprises: a cutting corner part 18c on which a part of a cutting edge 22 is formed; a rake face 24 having a first rake face 24a and a second rake face 24b; a wall surface 32a having a first wall surface 32a1 and a second wall surface 32a2 which extend so as to form a recess 34; and a projection part 32. The rake face 24 has a portion of which a rake angle αa is increased in vicinity of the cutting corner part. The cutting edge 22 is located at a position at which boring and turning are processed by a same edge.SELECTED DRAWING: Figure 8

Description

  The present invention relates to a cutting tool.

  Multifunctional tools that enable drilling and inner / outer diameter cutting have been proposed. Among conventional multifunctional tools, for example, there is a tool whose body has a shape similar to that of a blade-exchangeable drill (see, for example, FIG. 2 and claim 3 of Patent Document 1). In some multifunctional tools, the cutting insert is a convex raised portion provided on the rake face, and has a protruding portion called a breaker protruding portion (for example, FIG. 2 of Patent Document 2). 1-3). The protrusion is an important part from the viewpoint of improving the chip disposability such as how to shorten the chip or to make the chip less bulky during turning.

Special table 2012-516244 gazette US Patent Application Publication No. 2008/0008545 (A1) Specification

  However, in conventional multi-function tools, the convex shape causes deformation of the chip during drilling, which makes the chip shape unstable, resulting in increased cutting resistance and damage to the cutting edge. Some have problems to do. In other words, the problem is that the chip dischargeability during drilling is not compatible with the chip disposal in turning. In other words, in conventional drilling with a multifunctional tool, it is preferable that the turning chips are short, but it is not always preferable that the drilling chips are short, and the protrusions for shortening the chips are not used in drilling. It may be better not to.

  Then, an object of this invention is to provide the cutting tool which can make compatible the chip discharge | emission property at the time of drilling, and the chip disposal property in turning.

One aspect of the present invention is a cutting tool having a cutting edge,
A cutting corner portion in which a part of the cutting edge is formed;
A rake face extending along the cutting edge, the first rake face and the second rake face being formed so as to be inclined inward of the cutting tool as they are separated from the cutting edge and sequentially arranged in a direction away from the cutting edge. A rake face, wherein the first rake face has a predetermined angle with respect to the flank face in a vertical section of the cutting edge, and the second rake face extends to the first rake face;
A wall surface extending to form a recess along the cutting edge together with the rake surface, the wall surface having a first wall surface and a second wall surface connected to the first wall surface;
A projection that is located in the vicinity of the cutting corner and on the first rake face and the second rake face,
The rake face has a portion where the rake angle increases in the vicinity of the cutting corner,
The cutting edge is a cutting tool that is disposed at a position where drilling and turning are processed with the same blade.

  As described above, the protrusions are indispensable from the viewpoint of improving chip disposal such as shortening the chips in turning, but in terms of chips in drilling, the cutting speed on the side of the cutting corner having the protrusions is the central blade. Since the curl radius on the side of the cutting corner increases, and the protrusion deforms the chip at locations where the chip curl radius is large, the chip shape becomes non-uniform and unstable. An event such as an increase in the number is likely to occur. In this respect, in the present embodiment as described above, the rake face has a portion where the rake angle is increased in the vicinity of the cutting corner portion, so that the breaker height (from the cutting edge to the upper end of the second wall surface is higher than that of the conventional structure. It is possible to improve the chips during drilling. In addition, since the cutting edge is arranged at the position where drilling and turning are processed with the same blade, the projection shape (rake face shape) for multi-function tools that can handle both drilling and turning By doing so, it is possible to improve the chip dischargeability at the time of drilling without impairing the chip disposal at the time of turning.

  In the cutting tool of the above aspect, the second rake face may be a flat surface.

  In the cutting tool of the above aspect, the second rake face may be a curved surface.

  In the cutting tool of the above aspect, the first wall surface may have an opening angle of 90 ° to 160 ° with respect to the first rake face.

  In the cutting tool of the above aspect, the height of the protrusion may be within 0.2 mm with respect to the cutting edge.

  In the cutting tool of the above aspect, the second wall surface may have an opening angle of 90 ° to 160 ° with respect to the first rake face.

  In the cutting tool according to the above aspect, the rake face of the cutting corner portion may have a portion where the rake angle is increased inside.

  In the cutting tool of the above aspect, the second rake face may have a shape that disappears at a portion away from the cutting corner portion.

  In the cutting tool of the above aspect, when the depth from the cutting edge of the cutting tool to the deepest portion of the recess is the breaker depth, and the height from the cutting edge to the upper end of the second wall surface is the breaker height, the second scoop For the surface, the height of the breaker is set to a height at which chips during drilling are guided to the outside of the second wall surface, and the depth of the breaker is set to a depth at which chips during turning are guided so as to enter the recesses. It is preferable that

  In this aspect, the height is such that the chips at the time of drilling are guided to the outside of the second wall surface, that is, the scraper height can be reduced as compared with the conventional structure in order to improve the chips at the time of drilling. The surface has a two-stage configuration, and has a multi-functional tool projection shape (rake face shape) that can be used for both drilling and turning, so that chip processing is not hindered during drilling. It is possible to improve the chip discharging performance in

It is a perspective view showing an example of a cutting insert which is one mode of a cutting tool. It is a top view of a cutting insert. It is a front view (view seen from the side with a cutting corner part) of a cutting insert. It is a right view of a cutting insert. It is a perspective view which expands and shows the cutting corner part of the cutting insert. It is a perspective view which expands and shows the cutting corner part of the cutting insert from another angle. It is a fragmentary sectional view of the cutting insert in the VII-VII line of FIG. It is a figure which expands and shows the partial cross section of the cutting insert. It is a fragmentary sectional view of the cutting insert explaining the mode of the chip at the time of drilling. It is a fragmentary sectional view of the cutting insert explaining the mode of the chip at the time of turning. It is sectional drawing which shows another form of the cutting insert. It is a figure which shows an example of the cutting tool main body with which the cutting insert was mounted | worn. (A) It is a figure which shows the chip | tip at the time of drilling using the cutting insert based on this invention, and the chip | tip at the time of drilling using the conventional cutting insert. It is a reference figure used for detailed explanation of the section structure of a cutting insert.

  Hereinafter, preferred embodiments of a cutting tool according to the present invention will be described in detail with reference to the drawings.

[First Embodiment]
The cutting insert 10 according to the first embodiment of the present invention has a substantially rhomboid plate shape (see FIGS. 1 and 2). The cutting insert 10 has two substantially rhombic end faces 12 and 14 facing each other, and a peripheral side face 16 extending between the two end faces 12 and 14. In the cutting insert 10, an axis A that extends through the two end faces 12 and 14 is defined (see FIG. 3 and the like). One end surface 12 of the two end surfaces 12 and 14 is, for example, an upper surface (represented by reference numeral 18 in the following description and drawings), and the other end surface 14 is a lower surface (represented in the following description and drawings). 20), and is configured to function as a seating surface that comes into contact with the bottom surface of the insert mounting seat provided on the tool body 100 of the cutting tool (see FIG. 12 and the like). It should be noted that the expressions “upper surface” and “lower surface” in the present specification are merely for convenience, and this does not determine the vertical vertical arrangement, and does not prevent the use of the cutting insert 10 by switching the upper and lower sides. . In addition, regarding the partial cross section of the cutting insert 10, the structure representing the characteristics of the present invention is shown in an easy-to-understand manner in FIG. 8 and the like, and the detailed structure, dimensions, angles, etc. will be described with reference to FIG. .

  The cutting edge 22 is related to a ridge line portion of the cutting corner portion 18c forming an acute angle of the upper surface 18, and one cutting corner portion 18c of two acute angle portions on the upper surface 18 of the cutting insert 10 and a cutting corner portion 18d forming an obtuse angle. It is formed and has a corner portion forming an acute angle, a corner portion forming an obtuse angle, and a straight portion. The present invention does not limit the number of cutting edges formed with respect to one end face. The number of cutting edges formed with respect to one end face may be one or plural.

  A cutting edge 22 is formed at the intersection between the upper surface 18 and the peripheral side surface 16. The cutting edge 22 extends between the rake face 24 of the upper surface 18 and the flank face 26 of the peripheral side surface 16. However, the flank 26 is substantially acute with respect to one end face 12 (upper surface 18) and has a positive flank (see FIG. 4 and the like). The clearance angle may be set to 20 ° or less, and is set to 7 ° as an example in the cutting insert 10 of the present embodiment. The clearance angle may be partially different. For example, the clearance angle is 14 ° at the position shown in FIG.

  The cutting edge 22 is formed to be inclined so as to approach the lower surface 20 (see FIGS. 3 and 4). The inclination angle viewed from the horizontal direction toward the flank 26 is 7 °. The cutting edge 22 includes an arcuate cutting edge 22a and a linear cutting edge 22b (see FIGS. 5 and 6). The arcuate cutting edge 22 a is formed at the ridge line portion of the cutting corner portion 18 c that forms an acute angle of the upper surface 18. The arcuate cutting edge 22a has an arcuate shape (see FIG. 6 and the like). A preferable range of the radius of curvature of the arc constituting the arc-shaped cutting edge 22a is 0.2 to 1.2 mm, and in this embodiment, 0.4 mm. The linear cutting edge 22b extends so as to be continuous with the arcuate cutting edge 22a. The linear cutting edge 22b extends from both ends of the arcuate cutting edge 22a. That is, there are two linear cutting edges 22b per cutting edge 22. The arcuate cutting edge 22a and the linear cutting edge 22b become the cutting edge 22 that cuts into the work material.

  The cutting insert 10 is formed with a mounting hole 28 that penetrates both end faces 12 and 14 in the thickness direction. The central axis of the mounting hole 28 coincides with the axis C inclined with respect to the axis A. A boss surface 30 exists on the upper surface 18. These boss surfaces 30 are higher than the arcuate cutting edge 22a and the linear cutting edge 22b, and are on the same plane. That is, when defining a plane (hereinafter, referred to as a central plane) M that is perpendicular to the axis A and passes through the peripheral side surface 16 so as to divide the cutting insert 10 into two equal parts, the boss surface 30 and the central plane are defined. The distance to M is longer than the distance between the cutting edge 22 including the arcuate cutting edge 22a and the linear cutting edge 22b and the central plane M. All the boss surfaces 30 extend on a plane parallel to the central plane M.

  A chip breaker protrusion (hereinafter also simply referred to as a protrusion) 32 is formed in the inner region of the arcuate cutting edge 22a and the linear cutting edge 22b on the upper surface 18. The surface 32 a facing the cutting edge 22 side of the protrusion 32 forms a concave portion 34 extending along the cutting edge 22 on the upper surface 18 together with the rake face 24. The recess 34 may be referred to as a chip breaker groove. In addition, since the surface 32a of the protrusion 32 rises from the recess 34, it is hereinafter referred to as a rising wall surface (hereinafter also simply referred to as a wall surface). The rake face 24 and the wall surface 32a extend along substantially all of the cutting edge 22 so as to have a recess 34 in an arbitrary portion of the cutting edge 22 in a cross section orthogonal to the cutting edge 22.

  The wall surface 32a is a surface extending so as to form a recess along the cutting edge 22 together with the rake surface 24, and has a first wall surface 32a1 and a second wall surface 32a2 (see FIG. 6 and the like).

  The first rake face 24 a has a certain angle γ with respect to the flank face 26 in the vertical cross section of the cutting edge 22 of the cutting insert 10. The preferred range of the angle γ is, for example, 60 to 87 °, and in the present embodiment, γ = 64 ° in the middle of the cutting edge 22 of the cutting corner portion 18c (position on the bisector B).

  The cutting corner portion 18c has a second rake face 24b in addition to the first rake face 24a. The second rake face 24 b has a predetermined angle δ, for example, an angle of 5 ° to 20 ° with the first rake face 24 a in the vertical cross section of the cutting edge 22, and extends to the rake face 24.

  Of the recess 34, the surface extending from the arcuate cutting edge 22 a and the linear cutting edge 22 b toward the bottom of the recess 34 is the rake face 24. The rake face 24 is an inclined face that is inclined so as to gradually sink downward as it is spaced inward from the cutting edge 22, that is, to approach the central plane M. Thus, the rake face 24 is formed to have a positive rake angle.

  The rake face 24 is substantially composed of two faces. The rake face 24 has a first rake face 24a and a second rake face 24b that are sequentially arranged in a direction away from the cutting edge 22 in a direction orthogonal to the cutting edge 22. The first rake face 24 a is one area of the rake face 24, and is the first area of the rake face 24. The second rake face 24 b is another area of the rake face 24 and is a second area of the rake face 24.

  Such a rake face 24 will be further described based on a schematic cross-sectional view in which the rake angle, that is, the inclination angle is exaggerated (see FIG. 8). Here, a plane orthogonal to the axis A (hereinafter referred to as an axis orthogonal plane), that is, a plane parallel to the central plane M is defined. In the present embodiment, the axis orthogonal plane is substantially parallel to the lower surface 20 having a function as a seating surface, and may also be referred to as a horizontal plane. The inclination angles of the first rake face 24a and the second rake face 24b with respect to the axis-orthogonal plane can be defined as rake angles αa and αb. The rake angle αb of the second rake face 24b is larger than the rake angle αa of the first rake face 24a. Therefore, the rake face 24 is convex so as to protrude toward the upper face 18 as a whole.

  In this way, the rake face 24 is formed such that the rake angle αb of the second rake face 24b is larger than the rake angle αa of the first rake face 24a. Desirably, the rake angle αa of the first rake face is not less than 5 ° and not more than 25 °, and more desirably not less than 10 ° and not more than 20 °. In the present embodiment, the rake angle αa of the first rake face 24 is set to about 15 °. Desirably, the rake angle αb of the second rake face is not less than 10 ° and not more than 40 °, and is set to approximately 30 ° in the present embodiment. The difference between the rake angle αb and the rake angle αa (δ = αb−αa) is preferably in the range of 5 ° to 15 °.

  This is due to the following reason. That is, of the first rake face 24a and the second rake face 24b of the rake face 24, the first rake face 24a first affects the cutting of the work material. In the cutting insert in which the rake angle αa of the first rake face 24a is less than 5 °, the effect of reducing the cutting resistance by reducing the chip Z is insufficient regardless of the rake angle αb of the second rake face 24b. On the other hand, in the cutting insert in which the rake angle αa of the first rake face 24a exceeds 25 °, the cutting edge strength decreases regardless of the rake angle αb of the second rake face 24b. Therefore, for example, when cutting stainless steel, chipping and chipping are likely to occur.

  On the contrary, in the cutting insert in which the rake angle αb of the second rake face 24b is less than 10 ° and the rake angle αa of the first rake face 24a is in the above-described range, the first rake face 24a and the second rake face 24b The angle difference is small. This substantially dilutes the effect of providing the second rake face 24b. Further, in the cutting insert in which the rake angle αb of the second rake face 24b exceeds 40 ° and the rake angle αa of the first rake face 24a is in the above-described range, the thickness of the cutting insert around the cutting edge is insufficient. There is a possibility that the cutting edge is largely damaged.

  Further, the rising wall surface 32 a of the protruding portion 32 extends so as to form a recess 34 in the upper surface 18 together with the rake surface 24. The rising wall surface 32 a is a rising surface that rises from the recess 34, and extends so as to rise upward as it moves away from the rake face 24 with the bottom of the recess 34 as a starting point. Here, the rising wall surface 32a is formed of a flat surface or a curved surface, and is inclined so as to move away from the central plane M as it gradually moves away from the arcuate cutting edge 22a and the linear cutting edge 22b.

  The protrusion 32 is in the vicinity of the cutting corner portion 18c and is installed on the first rake face 24a and the second rake face 24b. The height (projection height) of the protrusion 32 is, for example, 0.4 mm based on the cutting edge 22. Further, the maximum height difference up to the protrusion 32 is 0.53 mm (that is, the depth from the cutting edge 22 to the bottom (deepest part) 34a is 0.13 mm). In a top view (plan view), the tip of the protrusion 32 has an R shape of R0.4 to R1 mm as a preferred range, for example, an R shape of R0.4 mm in this embodiment. The protrusion part 32 has a linear part continuously in the R shape. The straight line portion is connected to the second wall surface 32a2. The highest point on the basis of the cutting edge 22 of the protrusion 32 is, for example, 0.16 mm.

  In addition to the rising wall surface 32a, the protrusion 32 has a top surface 32c connected to the rising wall surface 32a and extending substantially parallel to the central plane M. The top surface 32c is a substantially flat surface. The top surface 32 c is formed to be higher than the cutting edge 22. This means that when a plane perpendicular to the axis A and passing through the cutting edge 22 is defined, this plane extends so as to cross the rising wall surface 32a.

  The inclination angle β of the rising wall surface 32a with respect to the axis orthogonal plane, that is, the horizontal plane is larger than the rake angle αb of the second rake face 24b. The inclination angle β is desirably set to 30 ° or more and 80 ° or less, and is set to approximately 45 ° in the present embodiment. When the inclination angle β is less than 30 °, the chips Z are difficult to deform in the desired curl at the protrusion 32 and cannot be processed in a short time. When the inclination angle β exceeds 80 °, the collision between the recess (chip breaker groove) 34 and the chips Z becomes too strong, and the cutting resistance may increase. Therefore, in this case, the occurrence frequency of chatter is increased and the tool life may be shortened.

  The rising wall surface 32a is connected to the bottom surface of the groove extending to the second rake surface 24b, that is, the bottom surface of the recess.

  In the cutting insert 10 of this embodiment, the rising wall surface 32a protrudes from the substantially horizontal and narrow groove bottom surface extending inward from the wall surface side end 24d of the second rake face 24b. This groove bottom surface can be omitted. In this case, the rising wall surface 32a continues to the second rake face 24b so as to protrude directly from the wall face side end 24d of the second rake face 24b. Therefore, in this case, the coupling portion 32b which is the rising portion of the rising wall surface 32a is on the extended surface S2 obtained by extending the second rake face 24b.

  In addition, the top surface 32c of the protrusion 32 is configured to be lower than the above-described boss surface 30 aligned in the same position. Such a configuration is particularly effective when the cutting edges 22 are formed on both end faces 12 and 14. In the case of a cutting insert that selectively uses one of the opposed end surfaces 12 and 14 as the upper surface 18, the other end surface is the lower surface. In this case, the boss surface that is the top surface of the recess (chip breaker groove) 34 on the other end surface can function as a seating surface that comes into contact with the bottom surface of the insert mounting seat provided in the cutting tool body 100.

  Further, the cutting insert 10 of the present embodiment has a shape in which the vicinity of the blade edge can be used for an inner diameter, an outer diameter, an end face, and a drilling process, and the drilling process and the turning process can be performed with the same cutting edge. But there is. Hereinafter, this configuration will be described (see FIG. 9 and the like).

  In the present specification, the arcuate cutting edge 22a of the cutting edge 22 in the direction perpendicular to the central plane M of the cutting insert 10 (in other words, the direction parallel to the axis A) and the bottommost part (the deepest part). (Part) 34a distance (dimension or height) is called the breaker depth, and is represented by the symbol Bd (see FIG. 8). Further, the distance (dimension or height) between the arcuate cutting edge 22a of the cutting edge 22 and the upper end of the second wall surface 32a2, that is, the protrusion 32, in the direction perpendicular to the central plane M is called the breaker height and is represented by the symbol Bh. (See FIG. 8).

  The rising wall surface 32a in the cutting insert 10 of this embodiment is formed as follows. That is, by forming the second rake face 24b, the breaker height Bh becomes a height at which chips Z during the drilling process are guided to the outside of the second wall surface 32a2 (see FIG. 9), and the breaker The depth Bd is a depth at which the chips Z during the turning process are guided so as to enter the recess 34 (see FIG. 10). A preferable numerical range for the breaker height Bh for realizing such a function is 0.1 mm to 0.8 mm, and a more preferable range is 0.3 mm to 0.5 mm. Thus, by increasing the breaker depth Bd at the second rake face 24b, the height of the protrusion 32 is not easily reduced, but the chip Z during turning is equivalent to the conventional shape of the breaker. It is possible to reduce the breaker height Bh with respect to the chips Z during drilling while maintaining the depth Bd (see FIGS. 9 and 10). In addition, in processing the chip Z, reducing the breaker height Bh basically works as described above. The breaker depth Bd is an auxiliary parameter, and the relative height increases by the chip Z being drawn into the recess 34.

  The rake face 24 has a two-stage configuration having the first rake face 24a and the second rake face 24, and the relative height of the protrusion 33 can be lowered to reduce the breaker height Bh compared to the conventional structure. By doing so, it becomes possible to improve the dischargeability of the chips Z at the time of drilling without impairing the processability of the chips Z at the time of turning (see FIG. 10) ( (See FIG. 9). In the present embodiment, the projecting portion 32 is effective only by turning using only the cutting edge 22 in the vicinity of the cutting corner portion 18c by providing a two-step rake face with a large rake angle only in the vicinity of the cutting corner portion 18c. I am doing so. That is, the second rake face 24b makes it easy to deepen the concave portion 34 (the breaker depth Bd becomes easy to deepen). Therefore, even with the same breaker projection height (that is, the breaker height Bh is the conventional one). The same effect as when the height of the chip breaker groove is increased. Note that there is no specific numerical range in the vicinity of the cutting corner portion 18, and the specific range of “near” can vary depending on the structure of the cutting insert 1, the cutting mode, the cutting target, and the like. As an example only, “near” is, for example, a range within a distance of 1 mm from the cutting corner portion 18c. However, as described above, without disturbing the processability of the chip Z during turning, and at the time of drilling As long as it is possible to improve the dischargeability of the chips Z, the “near” range is not limited to a specific numerical range.

  In general, the protrusion 33 is shaped so as to eject the chip Z in an optimal state. If it is a conventional cutting insert (cutting tool), the chip Z and turning (hole expanding) processing are usually performed during drilling. The chip Z of the time follows the same path and hits the chip breaker. In this respect, in the present embodiment, the chip Z hits or does not hit the surface (the rising wall surface 32a) constituting the chip breaker in drilling and turning, in other words, the chip Z is a recess (chip breaker groove) 34. A shape that can control whether to enter or not (in other words, a shape that allows you to choose whether to use a wall or not) is realized. Specifically, as is clear from the above description, in the cutting insert 10 of the present embodiment, the breaker depth Bd is deeper and the breaker height Bh is lower than the conventional structure. The breaker depth Bd is, for example, 0.05 mm to 0.5 mm, and preferably 0.08 mm to 0.2 mm.

  From the viewpoint of finely cutting the chips Z during turning, the recess 34 may be configured so that the distance from the horizontal cutting edge 22 to the rising wall surface 32a in this specification is shortened. Good. If the distance is short, the chips Z are likely to rise and hit the wall surface 32a even when the cutting conditions change. Note that the corresponding cutting conditions are the cutting ap and the feed f. In addition, it is advantageous that the distance from the cutting edge 22 to the rising wall surface 32a in the horizontal direction is shorter when “the cutting ap is small” and “the feed f is small”.

  The cutting insert 10 described above is detachably mounted on an insert mounting seat provided in the cutting tool body (tool body) 100 (see FIG. 12). The cutting insert 10 is placed on the insert mounting seat with the lower surface 20 having a function as a seating surface and at least a part of the peripheral side surface 16 abutting against the bottom surface and the wall surface of the insert mounting seat, respectively. A screw hole is formed in the insert mounting seat. The cutting insert 10 is detachably fixed to the cutting tool main body 100 by screwing a screw that engages or passes through the mounting hole 28 of the cutting insert 10 into the screw hole of the insert mounting seat.

  The cutting tool main body 100 has a chip discharge groove 102 so that drilling is possible (see FIG. 12). The shank diameter of the cutting tool body 100 is, for example, about 20 mm. The cutting tool main body 100 is fixed to the machine tool via a sleeve, and an inner diameter, an outer diameter, an end face, and a hole can be drilled.

  The attachment mechanism or means for attaching the cutting insert 10 to the cutting tool body 100 is not limited to such a configuration. Other mechanical or chemical mechanisms or means may be employed as the attachment mechanism or means.

  In the case of the cutting insert 10 that can be used on both sides, selectively using both of the opposite end surfaces as the upper surface, one end surface (the end surface 12 or the end surface 14) can abut on the bottom surface of the insert mounting seat.

  In the cutting insert 10 attached to the cutting tool main body 100, the upper surface 18 is oriented in the direction of rotation of the workpiece during cutting. At this time, the cutting edge 22 at the tip end in the axial direction is used as the main cutting edge when drilling and turning the inner and outer diameters, and the cutting edge 22 extending in the outer peripheral direction is used as the main cutting edge when processing the end face. Further, at the time of this cutting, the remaining linear cutting edge 22b of the working cutting edge 22 and the remaining part that does not function as the horizontal cutting edge of the arcuate cutting edge 22a adjacent to the other linear cutting edge 22b are: It functions as a front cutting edge facing the machined surface side of the work material. Note that the working cutting edge is a portion of the cutting edge 22 that is cut into the work material, that is, a cutting edge that can participate in cutting, in the cutting tool to which the cutting insert 10 is attached.

  The cutting insert 10 is used, for example, to turn the outer peripheral surface of a work material that is fed in a direction parallel to the rotation center line of the work material and rotates around the rotation center line. In this case, the said horizontal cutting edge can contact a work material over the whole cutting in a direction (cutting direction) at right angles to a rotation centerline, and can mainly bear cutting. In this case, the front cutting edge can be in contact with the processed surface of the work material and be responsible for forming the processed surface.

  In the cutting process described above, the chips Z mainly generated by the horizontal cutting edge of the cutting insert 10 rise from the horizontal cutting edge and flow toward the wall surface 32a. At this time, the chip Z passes over the first rake face 24a while contacting the surface of the first rake face 24a (see FIG. 10 and the like).

  Moreover, in the cutting insert 10 which is a multi-function tool, in addition to the above-described operational effects, the rake angle of the second rake face 24b is made larger than the rake angle of the first rake face 24a as in the present embodiment. In some cases, chip disposal can be performed without bringing the chip Z into contact with the second rake face 24b (see FIG. 9). In that case, such a rake face configuration further contributes to a reduction in cutting resistance. Therefore, the heat generation of the cutting insert and the chips Z can be suppressed. In this case, since the contact area between the chip Z and the cutting insert is small, it is possible to suppress the heat generated in the chip Z from being propagated to the cutting insert. Therefore, an increase in the surface temperature of the cutting insert can be suppressed.

  On the other hand, simply increasing the rake angle of the rake face 24 generally reduces the cutting edge strength. In contrast, in the cutting insert 10 of the present embodiment, the size of the first rake face 24a (the length from the cutting edge 22) is reduced, and the second rake face 24b having a larger rake angle is the first rake face. It is formed adjacent to 24a. Accordingly, it is possible to minimize a decrease in the strength of the blade edge.

  The chips Z that have passed over the first rake face 24a flow onto the second rake face 24b. The rake angle αb of the second rake face 24b is larger than the rake angle αa of the first rake face 24a. That is, the rake face 24 has a convex shape. Accordingly, the chips Z flowing from the first rake face 24a to the second rake face 24b cannot positively or substantially contact the surface of the second rake face 24b. Therefore, while the temperature rise of the chip Z is suppressed, the abrasion resistance between the chip Z and the rake face is greatly suppressed. Therefore, the tool life of the cutting insert can be improved.

  As mentioned above, although the cutting insert 10 which concerns on embodiment of this invention was demonstrated, a various change can be applied to them. The shape of the upper surface and the like of the cutting insert 10 can be changed not only to a rhombus but also to a substantially polygon such as a square, a rectangle, a parallelogram, and a triangle. That is, the cutting insert 10 may be a substantially polygonal plate shape. Also, the cutting insert 10 can be made from a variety of materials. At least a part of the arc-shaped cutting edge and the linear cutting edge is made of a hard material such as cemented carbide, cermet or ceramic, an ultra-high pressure sintered body such as a diamond sintered body or a cubic boron nitride sintered body, or these Carbide, nitrides, oxides, carbonitrides, carbonates, carbonitrides, boronitrides of metals in the periodic table 4A, 5A, 6A by CVD, PVD, etc. It is preferable that the substrate is made of an abdominal membrane selected from the group consisting of a material, boronitride oxide, aluminum oxide, and titanium aluminum nitride, or an amorphous carbon thin film.

  Moreover, although the said embodiment demonstrated and demonstrated the cutting insert 10, this invention can be applied also to cutting tools other than a cutting insert, and a brazing tool. The present invention also relates to a cutting tool having the above-described features of the cutting insert in the blade portion. Such a cutting tool may have a chip or a blade portion attached integrally, and may include the rake face and the rising wall surface along the cutting edge of the blade portion.

  In addition, the second rake face 24b described in the above embodiment is not limited to a flat surface, and may be constituted by, for example, a curved surface (a curved surface such as a cylindrical surface). . Similarly, the first rake surface 24a described in the above embodiment is not limited to a flat surface, and may be formed of a curved surface having no fixed rake angle (see a modified example described later, see FIG. 14). .

  In addition, the shape of the protrusion 32 and the surface 32a (the first wall surface 32a1 and the second wall surface 32a2) can be variously changed according to the target cutting conditions.

[Second Embodiment]
The cutting insert 10 concerning 2nd Embodiment of this invention is shown in FIG. In FIG. 11, the shape is exaggerated for easy understanding of the features.

  The second rake face 24b has an angle of 20 ° with the first rake face 24a in the vertical cross section of the cutting edge 22, and has a shape that increases the breaker depth Bd. The breaker depth Bd is 0.1 mm to 0.2 mm.

  In the cutting insert 10 of the present embodiment, by increasing the breaker depth Bd at the second rake face 24b, the height of the protrusion 32 is not easily reduced, but with regard to the chips Z during turning, The breaker height Bh can be reduced with respect to the chips Z during drilling while maintaining the breaker depth Bd equivalent to the conventional shape.

[Example]
A cutting tool body 100 having a flute shape similar to a blade-tip replaceable drill is mounted with the cutting insert 10 according to the above-described embodiment (see FIG. 12), and drilling of the work material is performed to obtain a chip Z. The comparison was made with chips Z in the case of using a comparative product (a shape in which the second rake face was eliminated and the first rake face was extended).

  Chip Z in the case of drilling using a conventional cutting insert such as the above comparative product is too short for drilling (see FIG. 13A), resulting in increased cutting resistance and damage to the cutting edge On the other hand, in the case of drilling in this example, a continuous chip Z was obtained (see FIG. 13B). By appropriately making the rake face 24 into a two-stage shape and relatively lowering the height of the projecting portion 32, the chip Z processing performance during turning is improved without hindering the discharge of the chip Z in drilling. It was confirmed that things would be possible.

  In addition, when drilling was performed using a conventional cutting insert such as the above-mentioned comparative product, a problem of biting occurred, but in the case of drilling in this embodiment, such a problem should be avoided. Can do. Here, the two types of biting phenomenon that have conventionally occurred will be described as follows (i) and (ii).

  (i) A phenomenon of biting between the cutting edge and the workpiece. Chips that are forcibly curled (returned back) by the protrusion flow out toward the back of the hole (that is, toward the back of the recess). However, since there is no chip escape in the back of the hole, cutting is disturbed and the cutting edge is damaged. Actually, new chips are always created by cutting, so there is no "biting" of chips between the cutting edge and the workpiece, but a lot of chips gather in the hole and the hole is clogged. It becomes a state that is very similar to biting, and the cutting edge may be damaged.

  (ii) Phenomenon that is caught between the tool outer clearance and the workpiece. The outer periphery of the tool on the rear side of the cutting edge is released (so as not to rub the workpiece) so that the hole diameter to be machined is determined by the cutting edge. If the chips become finer, it becomes easier to enter this gap, and the work may be scratched or damaged outside the cutting edge of the tool.

[Modification]
A modification of the cutting insert 10 will be described below with reference to the drawings (see FIG. 14).

  In the cutting insert 10 according to this example, the horizontal distance Wa from the cutting edge 22 to the terminal end portion of the first rake face 24a, that is, the rising wall side end 24c, is the arcuate cutting edge 22a provided in the cutting corner portion 18c. It is smaller than the radius of curvature. The distance Wa is defined in a direction perpendicular to the cutting edge 22 and perpendicular to the axis A as viewed from the end face side.

  Similarly to the distance Wa, the horizontal distance Wb from the cutting edge 22 to the end portion of the second rake face 24b, that is, the rising wall-side end 24d is orthogonal to the cutting edge 22 as viewed from the end face side and the axis A (See FIG. 14). As an example of a suitable distance, the distance Wa in this embodiment is 0.2 mm and Wb = 0.3 mm. Moreover, the preferable range of Wb is 1.5 to 2 times of Wa.

  The rising wall surface 32a is connected to the second rake face 24b (when the cutting insert 10 is formed with the bottom of the recess 34, which is a chip breaker groove, or the bottom of the groove extending to the bottom, ie, the bottom of the recess. Is connected to the lowest part or the bottom of the groove. When the rising wall surface 32a starts to rise from the bottom surface of the groove, the rising portion, that is, the coupling portion 32b is located lower than the extension surface S1 or the extension line L1 of the first rake face 24a, that is, on the center plane M side (on the seating surface side). And) higher than the extension surface S2 or the extension line L2 of the second rake face 24b, that is, on the side away from the central plane M (on the upper surface 18 side).

  Similarly to the distances Wa and Wb, the horizontal distance Wc from the cutting edge 22 to the rising portion of the rising wall surface 32a is defined in a direction orthogonal to the cutting edge 22 and orthogonal to the axis A as viewed from the end face side. (See FIG. 14). The distance Wc is desirably 0.4 mm or more and 2 mm or less, and is set to 0.5 mm which is within the range in this embodiment.

DESCRIPTION OF SYMBOLS 10 ... Cutting insert (cutting tool), 12 ... End surface, 14 ... End surface, 16 ... Peripheral side surface, 18 ... Upper surface, 18c ... Cutting corner part, 18d ... (The obtuse angle) Cutting corner part, 20 ... Lower surface, 22 ... Cutting Blade, 22a ... Arc cutting edge, 22b ... Linear cutting edge, 24 ... Rake face, 24a ... First rake face, 24b ... Second rake face, 24c ... Rising wall side edge, 24d ... Rising edge wall edge 26: Flank, 28 ... Mounting hole, 30 ... Boss surface, 32 ... Projection (chip breaker raised portion), 32a ... Surface (rise wall surface), 32a1 ... First wall surface, 32a2 ... Second wall surface, 32b ... Coupling part, 32c ... top surface, 34 ... recess (chip breaker groove), 34a ... bottom part (deepest part), 100 ... tool body, 102 ... chip discharge groove, A ... axis, B ... bisector, Bd ... Breaker depth, Bh ... Breaker Height, C ... Axis, M ... Center plane, L1 ... Extension line of first rake face, L2 ... Extension line of second rake face, S1 ... Extension face of first rake face, S2 ... Extension of second rake face Surface, Wa: Horizontal distance from the cutting edge 22 to the end portion of the first rake face 24a, that is, the rising wall side end 24c, Wb: End point of the second rake face 24b from the cutting edge 22, that is, the rising wall side edge Horizontal distance up to 24c, Wc ... Horizontal distance from cutting edge 22 to rising portion of rising wall surface 32a, Z ... chip, αa ... rake angle of first rake face, αb ... rake angle of second rake face , Β: an inclination angle of the rising wall surface with respect to the axis orthogonal plane, γ: an angle of the first rake face with respect to the flank face in a vertical section of the cutting edge of the cutting corner, δ: an angle of the second rake face with respect to the first rake face (= Αb−α a)

The rake face 24, a two-stage configuration having a first rake face 24a and the second rake face 24 b, by lowering the relative height of the protrusions 33 may reduce the breaker height Bh than the conventional structure The configuration can be realized, and by doing so, it becomes possible to improve the dischargeability of the chips Z during drilling without impairing the processability of the chips Z during turning (see FIG. 10). (See FIG. 9). In the present embodiment, the projecting portion 32 is effective only by turning using only the cutting edge 22 in the vicinity of the cutting corner portion 18c by providing a two-step rake face with a large rake angle only in the vicinity of the cutting corner portion 18c. Like that. That is, the second rake face 24b makes it easy to deepen the concave portion 34 (the breaker depth Bd becomes easy to deepen). Therefore, even with the same breaker projection height (that is, the breaker height Bh is the conventional one). The same effect as when the height of the chip breaker groove is increased. Note that there is no specific numerical range in the vicinity of the cutting corner portion 18, and the specific range of “near” can vary depending on the structure of the cutting insert 1, the cutting mode, the cutting target, and the like. As an example only, “near” is, for example, a range within a distance of 1 mm from the cutting corner portion 18c. However, as described above, without disturbing the processability of the chip Z during turning, and at the time of drilling As long as it is possible to improve the dischargeability of the chips Z, the “near” range is not limited to a specific numerical range.

Claims (9)

A cutting tool having a cutting edge,
A cutting corner portion in which a part of the cutting edge is formed;
A rake face extending along the cutting edge, wherein the first rake face is formed so as to incline inward of the cutting tool as it is away from the cutting edge, and is sequentially arranged in a direction away from the cutting edge. And a second rake face, the first rake face has a predetermined angle with respect to the flank face in a vertical section of the cutting edge, and the second rake face extends to the first rake face. Rake face,
A wall surface extending to form a recess along the cutting edge together with the rake surface, the wall surface having a first wall surface and a second wall surface connected to the first wall surface;
Protruding portions installed in the vicinity of the cutting corner portion and on the first rake face and the second rake face,
The rake face has a portion where a rake angle is increased in the vicinity of the cutting corner portion,
The said cutting blade is a cutting tool arrange | positioned in the position which processes a drilling process and a turning process with the same blade.   The cutting tool according to claim 1, wherein the second rake face is a flat surface.   The cutting tool according to claim 1, wherein the second rake face is a curved surface.   The cutting tool according to any one of claims 1 to 3, wherein the first wall surface has an opening angle of 90 ° to 160 ° with respect to the first rake face.   The cutting tool according to any one of claims 1 to 4, wherein a height of the protrusion is within 0.2 mm with respect to the cutting edge.   The second wall surface has an opening angle of 90 ° to 160 ° with respect to the first rake surface. The cutting tool according to any one of claims 1 to 5.   The cutting tool according to any one of claims 1 to 6, wherein a rake face of the cutting corner portion has a portion having a rake angle increased inside.   The cutting tool according to any one of claims 1 to 7, wherein the second rake face has a shape that disappears at a portion away from the cutting corner portion.   When the depth from the cutting edge of the cutting tool to the deepest part of the recess is the breaker depth, and the height from the cutting edge to the upper end of the second wall surface is the breaker height, the second rake face is The breaker height is set to a height at which chips at the time of drilling are guided to the outside of the second wall surface, and the breaker depth is guided so that chips at the time of turning process enter the recesses. The cutting tool according to any one of claims 1 to 8, which has a depth.