Cutting tools

Abstract

By accurately inspecting and measuring (correcting) the relative position of the protrusions to the cutting edge, it becomes easier to position them appropriately, and by devising the arrangement of the protrusions, chip evacuation performance is improved regardless of the insert shape. [Solution] A cutting tool comprising an upper surface 10, a lower surface, a side surface, a cutting edge 60 including a pair of main cutting edges 61 and a corner cutting edge 62, a first upper surface 11 and a second upper surface 12, an inclined surface 40, a groove 70 provided on the second upper surface 12, and a first projection 41 and a second projection 42 provided so as to protrude from the inclined surface 40. The first projection 41 extends along the extension line 70eL of the groove 70, and the second projection 42 is positioned symmetrically with respect to the extension line 70eL. At the intersection point P1 of the corner cutting edge 62 and the bisector Ba in a top view, if the distances from the imaginary line VL that intersects the bisector Ba perpendicularly to the tip 41t of the first projection 41 and the tip 42t of the second projection 42 are L1 and L2, respectively, then L1

Description

Technical Field

[0004] , , , , , , ,

[0001] The present invention relates to a cutting tool.

Background Art

[0002] In order to meet the demand for reducing the burr R in broaching of a workpiece using hardened steel, a cutting tool (turning tool) for finish machining with a small radius of curvature of the corner R is required (see Patent Documents 1 to 4). For example, in Patent Document 1, a protrusion composed of a breaker main wall and a sub-wall is provided, and the breaker main wall is arranged so as to satisfy predetermined conditions, thereby improving the chip disposal performance in finish machining. In such a cutting tool with a small corner R, since the deviation of the protrusion functioning as a breaker with respect to the cutting edge in finish machining easily affects the performance, it is necessary to accurately inspect and measure (correct) the relative position of the protrusion with respect to the cutting edge in the manufacturing process of the cutting tool.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Patent Document 2

Patent Document 3

Patent Document 4

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, as mentioned above, it is actually difficult to achieve accurate inspection and measurement (correction), and ultimately a suitable placement, by measuring the protrusion itself that functions as a breaker. This is especially true for cutting tools where the radius of curvature of the corner cutting edge is relatively small, such as a corner R of 0.2 [mm] or less, the cutting edge angle is designed at a sharp angle, and the rake face area around the corner cutting edge is small. Furthermore, regardless of the insert shape, even for cutting tools with small corner radii, there is still room for improvement in the structure and placement of the protrusion from the perspective of improving chip evacuation during finishing.

[0005] Therefore, the present invention aims to provide a cutting tool that makes it easier to appropriately position the projections by accurately inspecting and measuring (correcting) their relative positions to the cutting edge, and that improves chip evacuation performance during finishing regardless of the insert shape by devising the arrangement of the projections. [Means for solving the problem]

[0006] In order to solve these problems, the inventors have conducted various studies. For example, various breakers have been devised to improve chip handling performance, as described in Patent Documents 1 and 2, but it can be difficult to apply these to products where the area of ​​the rake face around the corner cutting edge is small. In other words, when the radius of curvature of the corner cutting edge is relatively small and the cutting edge angle is designed at a sharp angle, it can be difficult to apply these breakers because the area of ​​the rake face around the corner cutting edge is small. Furthermore, even if they can be applied, the protrusions have complex shapes and intersect with various components such as other protrusions and rake faces, making it difficult to obtain contour lines that are effective for measurement and inspection. Therefore, it is difficult to perform accurate inspection and correction by measuring the protrusions themselves, and it can be said that it is difficult to manufacture products in which the position of the breaker is not biased relative to the cutting edge.

[0007] One aspect of the present invention is a cutting tool conceived based on the findings obtained through the above-described examination, Top surface and, A lower surface provided so as to face the upper surface, a side surface connecting the upper surface and the lower surface, a cutting edge including a pair of main cutting edges formed on a part of a ridge line formed by an intersection line of the upper surface and the side surface, and a convex curved corner cutting edge connecting the pair of main cutting edges, a first upper surface and a second upper surface formed on the upper surface and separated from the lower surface more than the first upper surface, an inclined surface connecting the first upper surface and the second upper surface, a groove provided on the second upper surface, extending such that one or two or more are arranged symmetrically with respect to the bisector of the angle formed by the pair of main cutting edges on the bisector of the angle formed by the pair of main cutting edges, a first protrusion and a second protrusion provided so as to protrude from the inclined surface, comprising, the first protrusion extends along a line on the extension line of the groove or a line parallel to the extension line, the second protrusions are arranged symmetrically about the bisector of the angle formed by the pair of main cutting edges, and extend so as to approach the extension line of the groove as they approach the corner cutting edge, at the intersection of the bisector of the angle formed by the corner cutting edge and the pair of main cutting edges in a top view, when the distances from the tip of the first protrusion and the tip of the second protrusion to a virtual line perpendicular to the bisector of the angle formed by the main cutting edges are L1 and L2 respectively, L1 < L2, In a side view seen from a direction perpendicular to the bisector of the angle formed by the main cutting edges and parallel to the upper surface, when the distances in the direction perpendicular to the upper surface from the first upper surface to the top of the first protrusion, the top of the second protrusion, and the second upper surface are h1, h2, and h3 respectively, h1 < h2 < h3, it is a cutting tool.

[0008] According to the cutting tool as described above, by providing a groove serving as a reference for measurement and inspection on the upper surface, it is possible to accurately inspect and measure the positions of protrusions (first protrusion, second protrusion) that can function as a breaker based on the groove. Therefore, even when the area of the rake face where the protrusions (first protrusion, second protrusion) can be arranged is small, it is possible to obtain a cutting tool in which the protrusions suitable for finish machining are accurately arranged at suitable positions.

[0009] Furthermore, with the cutting tool described above, by providing protrusions (first protrusion, second protrusion) with a well-designed arrangement or structure, it is possible to improve chip handling performance during finishing regardless of the insert shape.

[0010] In the cutting tool described above, if the angles of rise between the inclined surface, the first projection, and the second projection, respectively, and the first upper surface are θ, θ1, and θ2, respectively, then θ1 < θ < θ2 may also be the case.

[0011] In the cutting tool described above, if the inclined surface, the first projection, or the second projection is curved when viewed from the side, θ, θ1, or θ2 may be values ​​obtained by interpolating the angles of the upper and lower ends of the inclined surface, the first projection, or the second projection, respectively.

[0012] In the cutting tool described above, the groove may have a shape that includes a pair of side walls.

[0013] In the cutting tool described above, at least a portion of at least one pair of groove ridges between the side wall and the second upper surface may be parallel.

[0014] In the cutting tool described above, at least a portion of the groove ridge may be edge-shaped.

[0015] In the cutting tool described above, the groove may have a shape in which one end has a constant groove width and the other end widens as it approaches the cutting edge.

[0016] In the cutting tool described above, the groove may have a shape in which one end has a constant groove width and the other end narrows in width as it approaches the cutting edge.

[0017] In the cutting tool described above, multiple grooves may be provided.

[0018] In the cutting tool described above, the grooves may be arranged symmetrically with respect to the angle bisector of the angle formed by the pair of main cutting edges.

[0019] In the cutting tool as described above, the groove may be used as a coolant supply groove for supplying coolant to the cutting edge, with one end of the groove intersecting the inclined surface.

[0020] In the cutting tool as described above, the number of the second protrusions may be odd.

[0021] In the cutting tool as described above, the second protrusions may be provided symmetrically with respect to the bisector of the angle formed by the pair of main cutting edges.

[0022] The cutting tool as described above may have a structure in which a sintered body containing cBN is joined to a cemented carbide member.

Brief Description of the Drawings

[0023] [Figure 1] It is a perspective view showing an insert (cutting tool) in one embodiment of the present invention. [Figure 2] It is a perspective view showing the peripheral part of the corner cutting edge of the insert. [Figure 3] It is a plan view showing the peripheral part of the corner cutting edge of the insert. [Figure 4] It is a side view of the peripheral part of the corner cutting edge of the insert, viewed from a direction perpendicular to the bisector of the angle formed by the main cutting edges and parallel to the upper surface. [Figure 5] It is a side view showing the rising angle θ of the inclined surface of the insert, the rising angle θ1 of the first protrusion, and the rising angle θ2 of the second protrusion, viewed from a direction perpendicular to the bisector of the angle formed by the main cutting edges and parallel to the upper surface. [Figure 6A] It is a perspective view showing another example 1 of the reference groove (groove). [Figure 6B] It is a plan view showing another example 1 of the reference groove. [Figure 7A] It is a perspective view showing another example 2 of the reference groove. [Figure 7B] It is a plan view showing another example 2 of the reference groove. [Figure 8A] It is a perspective view showing another example 3 of the reference groove. [Figure 8B] This is a plan view showing another example of a reference groove, number 3. [Figure 9A] This is a perspective view showing another example of the second projection. [Figure 9B] This is a plan view showing another example of the second projection. [Modes for carrying out the invention]

[0024] Hereinafter, preferred embodiments of the cutting tool according to the present invention will be described in detail with reference to the drawings. Below, as an example of a cutting tool, the present invention will be described with specific examples when applied to a cutting insert or a sintered body constituting the insert.

[0025] The insert 1 according to this embodiment is composed of a sintered body 3, such as a sintered body containing cBN, and a cemented carbide member 2 to which the sintered body 3 is joined (see Figure 1). The cemented carbide member 2 has a roughly rhombic shape defined by a diagonal along the longitudinal direction B1 and a diagonal along the width direction A1, and has a predetermined thickness in the height direction C1. Seats 2b are formed at both ends of the cemented carbide member 2 in the longitudinal direction B1, and the sintered body 3 is attached to each of these seats 2b (see Figure 1). The sintered body 3 has an upper surface 10, a lower surface 20, a side surface 30, an inclined surface 40, a ridge line 50, a cutting edge 60, a reference groove 70, and also a first projection 41 and a second projection 42 (see Figures 1, 2, etc.). The sintered body 3 is formed, for example, in the shape of a thin plate that is roughly triangular.

[0026] The upper surface 10 and the lower surface 20 are opposing surfaces that constitute both sides in the thickness direction of the thin plate-shaped sintered body 3, and of these, the lower surface 20 is the surface that is attached to the seat portion of the cemented carbide member 2. The upper surface 10 has a first upper surface 11 and a second upper surface 12 formed thereon (see Figure 4, etc.). The upper surface 10 and the lower surface 20 are connected by a side surface 30 (see Figures 1, 2, etc.).

[0027] A cutting edge 60 is formed on a portion of the ridge line 50, which is formed by the intersection of the top surface 10 and the side surface 30. The cutting edge 60 includes a pair of main cutting edges 61, a convex curved corner cutting edge 62 connecting the pair of main cutting edges 61, and a rake face 63 (see Figure 2, etc.). The pair of main cutting edges 61 are positioned symmetrically with respect to a predetermined line. This predetermined line is parallel to the longitudinal direction B1 when the sintered body 3 is attached to the seat portion 2b of the cemented carbide member 2 (see Figures 1 and 2). The angle between these two main cutting edges 61 is φ. The angle bisector Ba of the angle φ is parallel to the longitudinal direction B1 when the sintered body 3 is attached to the seat portion 2b of the cemented carbide member 2. The corner cutting edge 62 is formed with a relatively small radius of curvature R (for example, a radius of curvature R of 0.2 [mm] or less).

[0028] The first upper surface 11 formed on the upper surface 10 is composed of a surface that includes the rake face 63 of the cutting edge 60 (see Figure 3, etc.). The second upper surface 12 is composed of a surface that is further away from the lower surface 20 than the first upper surface 11, and in this embodiment, is composed of a plane that is parallel to the lower surface 20 and is furthest away from the lower surface 20. The first upper surface 11 and the second upper surface 12 are connected by an inclined surface 40 (see Figure 4, etc.).

[0029] The reference groove 70 is used as a measurement reference for the protrusions (first protrusion 41, second protrusion 42) and is provided so as to extend from the second upper surface 12 toward the cutting edge 60 (see Figure 2, etc.). Furthermore, by making one end of the reference groove 70 intersect with the inclined surface 40, it can also be used as a groove for supplying coolant. In this embodiment, the reference groove 70 is shaped to extend along the line bisector Ba of the angle φ formed by the pair of main cutting edges 61, with one end intersecting with the inclined surface 40, and functions as a groove that supplies coolant to the cutting edge 60 during cutting. By using the reference groove 70 to supply coolant in this way, coolant can be supplied to the area around the protrusions (first protrusion 41, second protrusion 42) and the cutting edge 60 during cutting, contributing to improved cooling and lubrication of the rake face 63 during machining, making coolant supply more efficient and improving chip handling performance. In this embodiment, the reference groove 70 is provided symmetrically with respect to the line bisector Ba of the angle φ formed by the pair of main cutting blades 61. A specific example of the size of the reference groove 70 is a groove width 70w of 0.1 [mm] and a depth of 0.5 [mm].

[0030] As mentioned above, the protrusions have complex shapes and intersect with various components such as other protrusions and rake faces, making it difficult to obtain a contour line that is effective for measuring and inspecting the protrusions themselves. However, by using a certain line, for example, a predetermined line obtained using the reference groove 70, as a reference, it becomes possible to indirectly measure the position of the protrusions relative to the cutting edge 60. Therefore, in this embodiment, such a reference groove 70 is made to function not only as a groove for supplying coolant, but also as a groove that serves as a reference for measurement and inspection. In such cases, by using the reference groove 70 as a reference, it becomes possible to accurately inspect, measure, or correct the position of the protrusions (first protrusion 41, second protrusion 42) that function as breakers. This is advantageous when the area of ​​the rake face on which the protrusions (first protrusion 41, second protrusion 42) can be placed is particularly small, in order to form a sintered body 3 or insert 1 in which the protrusions suitable for finishing are accurately placed in a suitable position. Furthermore, in this embodiment, the structure is designed so that the protrusions (first protrusion 41, second protrusion 42) and grooves (reference groove 70) can be formed in the same process by laser processing. However, if the center line of the reference groove 70 is misaligned with respect to the bisector of the corner radius (i.e., the bisector Ba of the angle φ formed by the pair of main cutting edges 61), the protrusions will also be misaligned by approximately the same amount. Therefore, in this embodiment, it is possible to inspect and correct the misalignment of the protrusions without directly measuring the protrusions, which are difficult to measure as described above. More specifically, "correction" here refers to correcting or improving input values ​​regarding the position of the protrusions, etc., when processing the next product (sintered body 3 or insert 1) in the production process by feeding back image data of a previously processed product. As an example, the reference groove 70 in the insert 1 or sintered body 3 of this embodiment has a shape that includes a pair of side walls 71 (see Figures 2, 3, etc.). Furthermore, by making at least a portion of the groove ridge 72 between these pair of side walls 71 and the second upper surface 12 edge-like, the position of the groove ridge 72 in the image can be more clearly determined. Making at least a portion of these pair of groove ridge 72 parallel also contributes to more clearly determining the reference position (see Figure 3, etc.).

[0031] As mentioned above, it is difficult to perform accurate inspection and correction by actually measuring the protrusions themselves. However, with an insert 1 or sintered body 3 that has a groove on the upper surface 10 that serves as a reference for measurement and inspection (in this embodiment, a reference groove 70), it is easy to obtain the contour line of the groove, making it easier to improve the positional accuracy of the protrusions that can function as breakers (first protrusion 41, second protrusion 42). For this reason, even when the area of ​​the rake face on which the protrusions (first protrusion 41, second protrusion 42) can be placed is small, it is possible to create a cutting tool in which the protrusions suitable for finishing are accurately placed in a suitable position. For example, when the radius of curvature R of the corner cutting edge 62 is 0.2 [mm] or less, the tip of the insert becomes considerably narrower, making it difficult to place a main wall that satisfies predetermined conditions depending on the insert shape. However, with this embodiment, it is easy to improve cutting performance even in such cases.

[0032] The first projection 41 and the second projection 42 are provided to function as chip breakers for chips generated during cutting. In this embodiment, the first projection 41 in the insert 1 or sintered body 3 extends along the extension line 70eL of the center of the reference groove 70 and is provided to protrude from the inclined surface 40 (see Figures 3 and 4). The second projections 42 come in pairs and, like the first projections 41, are arranged symmetrically with respect to the extension line 70eL of the center of the reference groove 70 (see Figure 3, etc.). These second projections 42 are shaped to extend inclined with respect to the extension line 70eL (and the line bisector Ba) when viewed from the top surface 10 along the height direction C1, so that they approach the extension line 70eL of the reference groove 70 as they approach the corner cutting edge 62 (see Figure 3).

[0033] Generally, it is preferable that the protrusions are small so as not to cause excessive chip restraint. Otherwise, it becomes difficult to obtain the desired surface quality in the finishing process due to vibration or chip entanglement. On the other hand, small protrusions may cause unintended chip riding due to workpiece shaft runout, variation in carburized layer thickness, etc., and the behavior of the chips may change. If the behavior of the chips changes, it may also damage the machined surface by entangling the workpiece. In this regard, in the present embodiment, a small first protrusion 41 mainly responsible for chip processing is arranged at a position near the cutting edge 60, and behind it, a second protrusion 42 that supplementarily takes charge of chip processing when the first protrusion 41 cannot perform chip processing is arranged in a two-stage configuration to solve such problems. More specifically, the first protrusion 41 mainly takes charge of the process of curling and breaking the chips, and the second protrusion 42 takes charge of the process of curling and breaking the chips when the first protrusion 41 wears and rides up.

[0034] The specific shape or size of such first protrusion 41 and second protrusion 42 is not particularly limited. As an example, the first protrusion 41 and second protrusion 42 in the insert 1 or sintered body 3 of the present embodiment have a shape or size defined by the following distance L, distance h, and rising angle θ (see FIGS. 3 to 5).

[0035] That is, first, at the intersection P1 of the bisector Ba of the angle φ formed by the pair of main cutting edges 61 in top view and the corner cutting edge 62, when the distances from the virtual line VL perpendicular to the bisector Ba of the angle φ formed by the main cutting edges 61 to the tip 41t of the first protrusion 41 and the tip 42t of the second protrusion 42 are L1 and L2 respectively, L1 < L2 (see FIG. 3). Here, the tips 41t and 42t refer to the part closest to the virtual line VL in each of the first protrusion 41 and second protrusion 42 in top view, or the part closest to the intersection P1 in each of the first protrusion 41 and second protrusion 42 in side view.

[0036] Also, in a side view, if the distances in the direction perpendicular to the upper surface 10 (in other words, the heights along the height direction C1) from the first upper surface 11 to the top 41A of the first protrusion 41, the top 42A of the second protrusion 42, and the second upper surface 12 are h1 (h1 is, for example, 0.07 [mm]), h2 (h2 is, for example, 0.13 [mm]), and h3 (h3 is, for example, 0.2 [mm]), respectively, then in the sintered body 3 of the present embodiment, h1 < h2 < h3 (see FIG. 4). Here, the "tops" (41A, 42A) refer to the highest parts (the parts closer to the second upper surface 12) in the height direction C1 of the first protrusion 41 and the second protrusion 42, respectively.

[0037] Also, in a side view, if the rising angles, which are the angles formed by the inclined surface 40, the first protrusion 41, and the second protrusion 42 with the first upper surface 10, are θ (θ is, for example, 55°), θ1 (θ1 is, for example, 30°), and θ2 (θ2 is, for example, 68°), respectively, then in the sintered body 3 of the present embodiment, θ1 < θ < θ2 (see FIG. 5). That is, in the present embodiment, the first protrusion 41 needs to have a relatively small rising angle θ1 in order to avoid excessive chip restraint by making the protrusion low, while the second protrusion 42 needs to have a relatively large rising angle θ2 because it needs to have a high protrusion to reliably process the chips riding over the first protrusion 41. When any of the inclined surface 40, the first protrusion 41, and the second protrusion 42 is a curve in a side view, the values obtained by interpolating the angles at the upper end and the lower end of the inclined surface 40, the first protrusion 41, and the second protrusion 42 may be used as the rising angles θ, θ1, and θ2. As an example of the interpolation method here, the value of the angle formed by the straight line connecting the upper end point and the lower end point of the protrusion (first protrusion 41, second protrusion 42) in a side view and the first upper surface 11 can be adopted.

[0038] As described above, the sintered body 3 or insert 1 of this embodiment, equipped with protrusions (first protrusion 41, second protrusion 42) and inclined surfaces 40 whose arrangement or structure is devised, makes it possible to improve chip handling performance during finishing even with small corner radii, regardless of the insert shape. Furthermore, coolant is supplied to the cutting edge 60 and the rough surface 63 through the reference groove 70, and the coolant promotes the treatment of chip curling that comes into contact with the protrusions (first protrusion 41, second protrusion 42), thereby facilitating chip handling.

[0039] [Another example of a reference groove 1] The reference groove 70 may have a constant groove width of 70w at one end, and the groove width of 70w may widen as it approaches the cutting edge 60 at the other end (see Figures 6A and 6B).

[0040] [Another example of a reference groove 2] The reference groove 70 may have a shape in which one end has a constant groove width 70w and the other end narrows in groove width 70w as it approaches the cutting edge 60, or it may have a shape in which one end narrows in groove width 70w as it approaches the cutting edge 60 and the other end has a constant groove width 70w (see Figures 7A and 7B).

[0041] [Another example of a reference groove 3] Multiple reference grooves 70 may be provided (see Figures 8A and 8B). In the cutting tool described above, the reference groove 70 may be provided symmetrically with respect to the line bisector Ba of the angle φ formed by the pair of main cutting edges 61.

[0042] [Another example of the second protuberance] The second projection 42 may consist of an odd number of projections instead of a pair (even number) (see Figures 9A and 9B).

[0043] The above-described embodiments are merely examples of preferred implementations of the present invention, and are not limited thereto. Various modifications are possible without departing from the spirit of the present invention. For example, as described in the above embodiments, the coolant groove 70 is merely one preferred example of a groove provided on the second upper surface 12. In short, the above-described reference groove 70 had both a coolant supply function and a function as a reference for measurement and inspection, but a simple groove without a coolant supply function may be provided separately to serve as a reference for measurement and inspection. Such a groove that serves as a reference for measurement and inspection only needs to have a shape such that a ridge appears on the second upper surface 12 that is parallel to the bisector Ba of the pair of main cutting blades 61.

[0044] Furthermore, although the above-described embodiment described the case in which the present invention is applied to a sintered body 3 such as a CBN sintered body or an insert 1 containing said sintered body 3, this is merely one preferred example. In addition, the present invention can also be applied to various cutting tools that do not have an insert, for example. [Industrial applicability]

[0045] This invention is preferably applied to cutting tools. [Explanation of Symbols]

[0046] 1… Insert (cutting tool) 2…Carbide components 2b…Seat part 3…cBN sintered body (sintered body) 10…Top surface 11…First top surface 12…Second top surface 20…Bottom surface 30... Side 40…(Inclined surface connecting the first and second upper surfaces) 41...first protrusion 41A… (The apex of the first projection) 41t… (the tip of the first projection) 42…Second protrusion 42A… (The apex of the second projection) 42t... (the tip of the second projection) 50...ridgeline 60...cutting edge 61…(a pair of) main cutting blades 62...Corner cutting edge 63... Scoop face 70...Reference groove (groove) 70eL…(Extension of groove) 70w…Groove width 71…(a pair of) side walls 72… Groove ridge (between the side wall and the second upper surface) A1…width direction B1... Long direction Ba...Bisector of the angle φ formed by the pair of main cutting blades 61 C1...Height direction h1... The distance from the first upper surface to the top of the first projection, in a direction perpendicular to the upper surface. h2…The distance from the first upper surface to the top of the second projection, perpendicular to the upper surface. h3... The distance from the first upper surface to the second upper surface, perpendicular to the upper surface. P1... The intersection of the angle bisector Ba of the angle φ formed by the pair of main cutting edges 61 and the corner cutting edge 62. L1... Distance from virtual line VL to the first projection L2…Distance from virtual line VL to the second projection VL...An imaginary line perpendicular to the angle bisector Ba of the angle φ formed by the main cutting edge. θ...Angle of rise of the inclined surface θ1…Angle of rise of the first projection θ2…Angle of rise of the second projection φ...Angle formed by a pair of main cutting blades 61

Claims

1. A cutting tool, Top surface and, A lower surface provided opposite the upper surface, A side surface connecting the upper surface and the lower surface, A cutting edge formed on a part of the ridge line formed by the intersection of the upper surface and the side surface, including a pair of main cutting edges and a convex curved corner cutting edge connecting the pair of main cutting edges, The upper surface is formed with a first upper surface and a second upper surface which is further away from the lower surface than the first upper surface, An inclined surface connecting the first upper surface and the second upper surface, A groove provided on the second upper surface, which extends such that one groove lies on the bisector of the angle formed by the pair of main cutting blades, or two or more grooves are arranged symmetrically with respect to the bisector, A first projection and a second projection are provided so as to protrude from the inclined surface, Equipped with, The first projection extends along the extension of the groove or along a line parallel to the extension, The second projection is arranged symmetrically with respect to the angle bisector of the angle formed by the pair of main cutting edges, and extends so as it approaches the corner cutting edge, it approaches the extension of the groove. In a top view, at the intersection of the angle bisector of the angle formed by the corner cutting edge and the pair of main cutting edges, if the distances from the imaginary line perpendicular to the angle bisector of the main cutting edges to the tip of the first projection and the tip of the second projection are L1 and L2, then L1 < L2. A cutting tool in which, in a side view taken from a direction perpendicular to the angle bisector of the angle formed by the main cutting edge and parallel to the upper surface, if the distances from the first upper surface to the top of the first projection, the top of the second projection, and the second upper surface in a direction perpendicular to the upper surface are h1, h2, and h3, respectively, then h1 < h2 < h3.

2. In the side view, if the angles of rise between the inclined surface, the first projection, and the second projection, respectively, and the first upper surface are θ, θ1, and θ2, then θ1 < θ < θ2, the cutting tool according to claim 1.

3. The cutting tool according to claim 2, wherein in the side view, if any of the inclined surface, the first projection, or the second projection is a curve, θ, θ1, or θ2 is a value obtained by interpolating the angle of the upper end and the angle of the lower end of the inclined surface, the first projection, or the second projection, respectively.

4. The cutting tool according to claim 1, wherein the groove has a shape that includes a pair of side walls.

5. The cutting tool according to claim 4, wherein at least a portion of at least one pair of groove ridges between the side wall and the second upper surface are parallel.

6. The cutting tool according to claim 5, wherein at least a portion of the groove ridge is edge-shaped.

7. The cutting tool according to any one of claims 1 to 6, wherein the groove has a constant groove width at one end and the groove width widens as it approaches the cutting edge at the other end.

8. The cutting tool according to any one of claims 1 to 6, wherein the groove has a constant groove width at one end and the groove width narrows as it approaches the cutting edge at the other end.

9. A cutting tool according to any one of claims 1 to 6, wherein a plurality of grooves are provided.

10. The cutting tool according to any one of claims 1 to 6, wherein the grooves are provided symmetrically with respect to the angle bisector of the angle formed by the pair of main cutting edges.

11. The cutting tool according to any one of claims 1 to 6, wherein the groove is used as a coolant supply groove for supplying coolant to the cutting edge, with one end of the groove intersecting the inclined surface.

12. The cutting tool according to any one of claims 1 to 6, wherein the number of the second protrusions is odd.

13. The cutting tool according to any one of claims 1 to 6, wherein the second projection is provided symmetrically with respect to the angle bisector of the angle formed by the pair of main cutting edges.

14. A cutting tool according to any one of claims 1 to 6, wherein a sintered body containing cBN is joined to a cemented carbide member.

Images