Cutting tool

Abstract

The present invention is provided with: a rake face (1); a flank surface (2); a cutting edge (3) which is disposed on a ridge line section where the rake surface (1) and the flank surface (2) are connected, and which has a V-shape in a plan view in which the rake surface (1) is viewed from the front; and a chip breaker (4) disposed on the rake face (1), the chip breaker (4) having: a first protrusion (41) protruding upward from the rake face (1); a second protrusion (42) that protrudes upward from the rake face (1), is disposed on the rear side of the first protrusion (41), and extends forward as the second protrusion (42) moves away from the bisector of the cutting edge (3) in the left-right direction; and a third protruding section (43) that protrudes upward from the rake face (1) and is disposed in front of the first protruding section (41), the first protruding section (41) and the second protruding section (42) protrude upward from the cutting edge (3), and the height of the third protruding section (43) in the vertical direction is lower than the height of the first protruding section (41) in the vertical direction.

Description

Technical Field

[0001] The invention relates to a cutting tool.

[0002] This application claims priority based on Japanese Patent Application No. 2022-125283 filed in Japan on August 5, 2022, and the contents are incorporated herein by reference. Background Art

[0003] Conventionally, there is known a cutting tool such as a cutting insert used when cutting a workpiece such as a metal (for example, Patent Documents 1 and 2).

[0004] This cutting tool comprises: a rake face; a flank face; a cutting edge arranged on a ridgeline connecting the rake face and the flank face and forming a V-shape in a plan view of the rake face viewed from the front; and a chip breaker arranged on the rake face.

[0005] Patent Document 1: Japanese Patent No. 6413516 (B)

[0006] Patent Document 2: Japanese Patent No. 4967721 (B)

[0007] For example, if the distance from the blade angle (knife corner arc) at the end of the cutting edge to the chip breaker is far, the chips are unlikely to come into contact with the chip breaker and are likely to stretch during low feed with a small feed amount, thereby deteriorating chip handling performance.

[0008] On the other hand, if the distance from the cutting edge to the chip breaker is simply shortened, the chips will be excessively curled, causing them to come into contact with the machined surface of the workpiece, thereby reducing the accuracy of the machined surface. Summary of the invention

[0009] One of the objects of the present invention is to provide a cutting tool which can maintain good chip disposability regardless of the amount of cutting and the like and can stably improve the machined surface accuracy.

[0010] [Mode 1 of the present invention]

[0011] A cutting tool, comprising: a rake face; a flank face; a cutting edge, which is arranged on a ridge portion connecting the rake face and the flank face, and is V-shaped in a plan view of the rake face observed from the front; and a chip breaker, which is arranged on the rake face, and when the direction in which the bisector of the cutting edge in the plan view extends is set as a front-to-back direction, the direction orthogonal to the bisector in the plan view is set as a left-right direction, and the direction orthogonal to the front-to-back direction and the left-right direction is set as an up-down direction, the chip breaker has: a first convex portion, which protrudes from the upper side of the rake face; a second convex portion, which protrudes from the upper side of the rake face and is arranged on the rear side of the first convex portion, and extends toward the front side as it moves away from the bisector in the left-right direction; and a third convex portion, which protrudes from the upper side of the rake face and is arranged on the front side of the first convex portion, the first convex portion and the second convex portion protrude further upward than the cutting edge, and the height of the third convex portion in the up-down direction is lower than the height of the first convex portion in the up-down direction.

[0012] In the cutting tool of the present invention, for example, during high feed (high feed) with a large feed rate, the chips generated by the cutting edge contact the first convex portion and the second convex portion of the chip breaker. That is, the chips are compressed and curled in a manner that they are supported at two points by the two convex portions arranged in the front-back direction and clamped by these convex portions. Therefore, thick chips can be stably curled, thereby maintaining good chip handling properties.

[0013] Specifically, the second convex portion extends toward the front side as it moves away from the bisector in the left-right direction. The direction in which the second convex portion extends is substantially the same as the direction in which the chips generated by the cutting edge flow out on the rake face, so that the chips are guided to the outflow direction by the second convex portion and stably curled by the two convex portions. Therefore, the chip handling performance is more stable.

[0014] Furthermore, during low feed with a small feed amount, the chips generated by the cutting edge contact the third protrusion located at the front side of the chip breaker. Therefore, the thin chips are prevented from extending and broken stably.

[0015] Specifically, the height of the third convex portion in the vertical direction is lower than the height of the first convex portion in the vertical direction, that is, the protrusion amount of the third convex portion from the rake face is small. Therefore, it is possible to suppress excessive curling of the chips contacting the third convex portion, thereby suppressing the chips from contacting the machined surface of the workpiece material. As a result, the machined surface accuracy can be well maintained.

[0016] As described above, according to the present invention, regardless of the cutting amount and the like, chip disposability can be maintained well and the machined surface accuracy can be stably improved.

[0017] [Mode 2 of the present invention]

[0018] The cutting tool according to aspect 1, wherein the second convex portion protrudes upward more than the first convex portion.

[0019] At this time, the chips that flow out while being supported at two points by the first and second convex parts are wound into a spiral shape by the height difference between these convex parts and are stably wound, so that the chip handling performance can be improved more stably.

[0020] [Mode 3 of the present invention]

[0021] The cutting tool according to aspect 1 or 2, wherein the chip breaker has a chip breaker wall, the chip breaker wall being arranged on the rear side of the second protrusion and protruding upward from the second protrusion.

[0022] At this time, the chips that have passed over the second protrusion to the rear side are stably processed by contacting the chip breaker wall.

[0023] [Mode 4 of the present invention]

[0024] A cutting tool according to any one of methods 1 to 3, wherein the cutting edge has: a cutting corner in the form of a convex curve; and a pair of straight edges connected to both ends of the cutting corner and extending in a straight line respectively, and the third convex portion is located lower than at least the cutting corner of the cutting edge.

[0025] At this time, the third convex portion is arranged below the cutting edge, so that during low feed, the chips generated by the cutting edge and contacting the third convex portion can be stably suppressed from curling excessively. Thus, the machined surface accuracy can be stably improved.

[0026] [Mode 5 of the present invention]

[0027] The cutting tool according to aspect 4, wherein the third convex portion is located on the front side of the center of the radius of curvature of the edge corner in the plan view.

[0028] In this case, the chips generated by the cutting edge during low cutting etc. can stably contact the third projections, so that the chip handling performance of the third projections can be more stably exerted.

[0029] [Mode 6 of the present invention]

[0030] The cutting tool according to aspect 4 or 5, wherein the first convex portion overlaps with the center of the radius of curvature of the edge corner in the plan view.

[0031] In this case, the chips generated near the boundary between the edge corner and the straight edge or the edge corner of the cutting edge during cutting can stably contact the first convex portion, so that the chip handling performance of the first convex portion can be more stably exerted.

[0032] [Aspect 7 of the present invention]

[0033] The cutting tool according to any one of aspects 1 to 6, wherein an angle between a ridge line formed on the second convex portion and the bisector in the plan view is 30° or more and 60° or less.

[0034] If the above angle is greater than 30° and less than 60°, the second convex portion can more stably perform chip processing performance regardless of the opening angle of the cutting edge in a plan view (the angle formed between a pair of straight edges) or the tool posture during cutting.

[0035] If the angle is less than 30° or greater than 60°, the chip outflow direction and the direction in which the second convex portion extends may differ greatly depending on the opening angle of the cutting edge or the tool posture during cutting, which may affect chip processability.

[0036] According to the cutting tool of the aspect of the present invention, it is possible to maintain good chip disposability regardless of the cutting amount and the like, and to stably improve the machined surface accuracy. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Figure 1 It is a perspective view showing the cutting tool according to the present embodiment.

[0038] Figure 2 It is a plan view (top view) showing the cutting tool according to the present embodiment.

[0039] Figure 3 It is a side view showing the cutting tool according to the present embodiment.

[0040] Figure 4 It is a magnified representation Figure 1 A stereogram of section IV.

[0041] Figure 5 It is a plan view (top view) showing a part of the cutting tool.

[0042] Figure 6 Yes means Figure 5 Cross-sectional view of section VI-VI.

[0043] Figure 7 Yes means Figure 5 Cross-sectional view of section VII-VII.

[0044] Figure 8 Yes means Figure 5 A cross-sectional view of section VIII-VIII.

[0045] Fig. 9 Yes means Figure 5 Cross-sectional view of section IX-IX.

[0046] Fig.10 Yes means Figure 5 Cross-sectional view of section XX. DETAILED DESCRIPTION

[0047] A cutting tool 10 according to an embodiment of the present invention will be described with reference to the accompanying drawings. The cutting tool 10 according to the present embodiment is, for example, a cutting insert of an indexable insert type turning tool for turning (cutting) a workpiece made of metal, etc. In addition, in the present embodiment, the cutting tool 10 is sometimes referred to simply as a tool, etc.

[0048] Although not specifically shown in the figure, the indexable insert type turning tool has a tool holder and a cutting tool (cutting insert) 10. The tool holder is made of, for example, steel. The tool holder has a concave insert mounting seat arranged at the end of the tool holder. The cutting tool 10 is made of, for example, cemented carbide. The cutting tool 10 is integrally formed by a single component. The cutting tool 10 is detachably mounted on the insert mounting seat.

[0049] like Figure 1 to Figure 3 As shown, the cutting tool 10 is plate-shaped. In the present embodiment, the cutting tool 10 is a polygonal plate, specifically a quadrilateral plate such as a rhombus plate. In more detail, the cutting tool 10 of the present embodiment has, for example, an outer shape of a rhombus blade (cutting blade) that conforms to the general ISO standard. However, it is not limited thereto, and the cutting tool 10 may also be a polygonal plate such as a triangular plate, a pentagonal plate, a hexagonal plate, etc.

[0050] The cutting tool 10 is a polygonal plate centered on the blade center axis C, and a pair of plate surfaces (front and back) thereof face the direction (blade axial direction) in which the blade center axis C extends. In addition, in this specification, the direction orthogonal to the blade center axis C is sometimes referred to as the blade radial direction, and the direction surrounding the blade center axis C is referred to as the blade circumferential direction. In the blade radial direction, the direction close to the blade center axis C is the inner side in the blade radial direction, and the direction away from the blade center axis C is the outer side in the blade radial direction.

[0051] In this embodiment, the cutting tool 10 is symmetrical in the axial direction of the insert. That is, the cutting tool 10 is a so-called double-sided cutting insert. Moreover, the cutting tool 10 is symmetrical in rotation of 180° around the insert center axis C.

[0052] The cutting tool 10 includes: a rake face 1 ; a flank face 2 ; a cutting edge 3 disposed on a ridge portion connecting the rake face 1 and the flank face 2 ; a chip breaker 4 disposed on the rake face 1 ; and a mounting hole 5 .

[0053] The front cutting face 1 and the chip breaker 4 are arranged on at least one plate surface (front surface) of a pair of polygonal plate surfaces of the cutting tool 10. In detail, the front cutting face 1 and the chip breaker 4 are arranged on a specified corner (an acute-angled corner in the present embodiment) among multiple corners of a plate surface. Furthermore, the back cutting face 2 is arranged on the outer peripheral surface of the cutting tool 10. In detail, the back cutting face 2 is arranged on a specified corner (an acute-angled corner in the present embodiment) among the outer peripheral surface of the cutting tool 10. Furthermore, the cutting edge 3 is arranged on a ridge portion where a plate surface of the cutting tool 10 is connected to the outer peripheral surface. In detail, the cutting edge 3 is arranged on a specified corner (an acute-angled corner in the present embodiment) among the said ridge portion of the cutting tool 10.

[0054] A predetermined corner portion of the cutting tool 10 where the rake face 1, the flank face 2, the cutting edge 3, and the chip breaker 4 are arranged may also be referred to as a "cutting edge portion".

[0055] In this embodiment, the cutting tool 10 is symmetrical in front and back and 180° rotationally symmetrical around the blade center axis C, so four groups consisting of a front cutting face 1, a back cutting face 2, a cutting edge 3 and a chip breaker 4 are provided on two acute angles on one plate surface (front) side and two acute angles on the other plate surface (back) side of the cutting tool 10. In addition, the mounting hole 5 is provided on the cutting tool 10 only once.

[0056] Figure 2 1 shows a plan view (top view) of the cutting tool 10 as viewed from the axial direction of the blade. Figure 5 1 is a plan view (top view) of the vicinity of the cutting edge 3 (the predetermined corner and the cutting edge) of the cutting tool 10 as viewed from the axial direction of the blade. Figure 2 and Figure 5 As shown, the cutting edge 3 is V-shaped in a plan view of the front face 1. Specifically, the cutting edge 3 has a cutting edge 3a in a convex curved shape and a pair of straight edges 3b connected to both ends of the cutting edge 3a and extending in straight lines.

[0057] [Definition of direction]

[0058] In the present embodiment, each configuration is described by appropriately setting an XYZ orthogonal coordinate system (three-dimensional orthogonal coordinate system) in each drawing.

[0059] exist Figure 5In the plan view of the cutting tool 10 shown, the direction in which the bisector B of the V-shaped cutting edge 3 extends is called the front-back direction. Specifically, the bisector B is equivalent to the angle bisector of the center angle formed between a pair of straight edges 3b in the plan view. The front-back direction is equivalent to the Y-axis direction in each figure. In the present embodiment, the bisector B is orthogonal to the blade center axis C. That is, the bisector B extends along the specified blade radial direction. In the front-back direction, the direction from the blade center axis C toward the blade angle 3a is called the front side (-Y side), and the direction from the blade angle 3a toward the blade center axis C is called the rear side (+Y side).

[0060] And, in Figure 5 In the plan view of the cutting tool 10 shown in FIG. 1 , the direction perpendicular to the bisector B is referred to as the left-right direction. The left-right direction corresponds to the X-axis direction in each figure. Figure 5 When the rake face 1 is viewed from the front, the direction from the bisector B toward the left is called the left side (-X side), and the direction from the bisector B toward the right is called the right side (+X side). In addition, one of the left and right sides may be referred to as one side in the left-right direction, and the other side may be referred to as the other side in the left-right direction.

[0061] Furthermore, in the left-right direction, a direction closer to the bisector B is referred to as an inner side (center side), and a direction farther from the bisector B is referred to as an outer side.

[0062] Furthermore, the direction orthogonal to the front-back direction and the left-right direction is referred to as the up-down direction. The up-down direction is equivalent to the Z-axis direction in each figure. In the up-down direction, the direction to which the front cutting face 1 points is referred to as the upper side (+Z side), and the direction opposite thereto is referred to as the lower side (-Z side). In the present embodiment, the up-down direction is equivalent to the axial direction of the blade.

[0063] like Figure 5 As shown, in the present embodiment, a predetermined corner portion (edge ​​portion) of the cutting tool 10 is formed in a bilaterally symmetrical shape with the bisector B as the axis of symmetry.

[0064] In addition, in the present embodiment, the front side, rear side, left side, right side, top side and bottom side are merely names used to illustrate the relative positional relationship of each part, and the actual configuration relationship when using tools, etc. may also be a configuration relationship other than the configuration relationships represented by these names.

[0065] 〔Rake face〕

[0066] like Figure 4 and Figure 5 As shown, the rake face 1 is arranged inside the cutting edge 3 on the plate surface of the cutting tool 10 facing the insert axial direction. Specifically, the rake face 1 is arranged adjacent to the cutting edge 3 on the inside of the cutting edge 3 in the insert radial direction. The rake face 1 has a land 15 and an inclined surface 16.

[0067] The land 15 is a portion of the rake face 1 that is directly connected to the cutting edge 3. The land 15 extends along the cutting edge 3 and is Figure 5 The overall shape is V in the plan view shown. Figure 6 and Figure 7 As shown in each cross-sectional view (longitudinal cross-sectional view) of , in the present embodiment, the margin 15 extends obliquely downward as it moves away from the cutting edge 3 along a virtual plane (hereinafter referred to as a reference plane Pr) that passes through the cutting edge 3 and is perpendicular to the vertical direction. That is, the margin 15 has a positive angle.

[0068] In the present embodiment, the “rake angle” refers to the inclination angle of each portion (each component) of the rake face 1 with respect to the reference plane Pr.

[0069] like Figure 4 and Figure 5 As shown in FIG. 1 , the inclined surface 16 is a portion of the rake face 1 disposed inside the land 15. That is, the inclined surface 16 is disposed farther from the cutting edge 3 than the land 15. The inclined surface 16 is connected to the land 15. The inclined surface 16 extends along the cutting edge 3 and is Figure 5 The overall shape is substantially V-shaped in the plan view shown. In the plan view, the inclined surface 16 is inclined downward as it moves away from the cutting edge 3 in a direction perpendicular to the cutting edge 3. Therefore, the rake angle of the inclined surface 16 is a positive angle.

[0070] like Figure 6 to Figure 10 As shown, the rake angle of the inclined surface 16 is larger than the rake angle of the land 15 toward the positive angle side.

[0071] 〔Flanking surface〕

[0072] like Figure 4 As shown in FIG. 1 , the flank face 2 is arranged on the outer peripheral surface of the cutting tool 10 facing the outer side in the radial direction of the blade. Specifically, the flank face 2 is arranged on a predetermined corner portion of the outer peripheral surface of the cutting tool 10 over the portion facing the front side, the left side, and the right side. The flank face 2 extends along the circumferential direction of the blade. The flank face 2 is arranged adjacent to the cutting edge 3 on the lower side of the cutting edge 3.

[0073] In the present embodiment, the cutting tool 10 is a double-sided type so-called negative insert, and the flank surface 2 is formed parallel to the insert center axis C. That is, the clearance angle of the flank surface 2 is 0°.

[0074] In addition, in this embodiment, the "back angle" refers to, for example, Figure 6 As shown, in a cross-sectional view perpendicular to the cutting edge 3, the inclination angle of the flank face 2 relative to a virtual straight line (not shown) passing through the cutting edge 3 and being orthogonal to the reference plane Pr.

[0075] like Figure 4 and Figure 5 As shown, the flank surface 2 includes an angular flank surface 21 and a pair of straight flank surfaces 22 connected to both ends of the angular flank surface 21 in the insert circumferential direction.

[0076] The angular relief surface 21 is a portion of the relief surface 2 connected to the edge corner 3a. The angular relief surface 21 is disposed on the portion of the relief surface 2 facing the front side (-Y side). Specifically, the angular relief surface 21 is disposed on the front end of the relief surface 2 and has a convex curved surface shape protruding toward the front side.

[0077] The linear flank surface 22 is a portion of the flank surface 2 connected to the linear cutting edge 3b. The linear flank surface 22 is in a planar shape.

[0078] One of the pair of linear flank surfaces 22 is disposed in the portion of the flank surface 2 facing the left side (-X side). One linear flank surface 22 is connected to one of the pair of linear edges 3b located on the left side of the bisector B. One linear flank surface 22 extends along one linear edge 3b.

[0079] The other linear flank surface 22 of the pair of linear flank surfaces 22 is disposed in a portion of the flank surface 2 that faces the right side (+X side). The other linear flank surface 22 is connected to the other linear edge 3b of the pair of linear edges 3b that is located to the right of the bisector B. The other linear flank surface 22 extends along the other linear edge 3b.

[0080] 〔Cutting edge〕

[0081] As described above, the cutting edge 3 has a blade angle 3a and a pair of straight edges 3b. In the cutting edge 3, the blade angle 3a is in a curved shape protruding toward the front side (-Y side), specifically in a convex arc shape. In the present embodiment, the blade angle 3a extends along the surface direction of the reference plane Pr perpendicular to the up-down direction. The blade angle 3a is included in the surface of the reference plane Pr as a whole. However, it is not limited to this, and the blade angle 3a can also be formed obliquely relative to the reference plane Pr.

[0082] A pair of straight edges 3b are connected to both ends of the blade length direction where the blade corner 3a extends. Figure 5 In the plan view shown, each straight edge 3b extends along each tangent line that is tangent to both ends of the edge corner 3a.

[0083] One of the pair of straight blades 3b is connected to one end (left end) of the blade corner 3a in the blade length direction. One straight blade 3b extends straightly toward the left side (-X side) as it moves from the connection portion with the blade corner 3a toward the rear side (+Y side). In the present embodiment, one straight blade 3b extends obliquely toward the lower side as it moves away from the connection portion with the blade corner 3a along the blade length direction extending from one straight blade 3b.

[0084] The other straight edge 3b of the pair of straight edges 3b is connected to the other end (right end) of the blade angle 3a in the blade length direction. The other straight edge 3b extends straightly toward the right side (+X side) as it moves from the connection portion with the blade angle 3a toward the rear side (+Y side). In the present embodiment, the other straight edge 3b extends obliquely toward the lower side as it moves away from the connection portion with the blade angle 3a along the blade length direction extended by the other straight edge 3b.

[0085] 〔Chip breaker〕

[0086] like Figure 4 and Figure 5 As shown, the chip breaker 4 is arranged inside the cutting edge 3 on the plate surface of the cutting tool 10 facing the insert axial direction. At least a part of the chip breaker 4 is arranged on the rake face 1. The chip breaker 4 has a first protrusion 41, a second protrusion 42, a third protrusion 43 and a chip breaker wall 44.

[0087] The first convex portion 41 protrudes upward from the rake face 1. Specifically, the first convex portion 41 includes a portion disposed on the inclined surface 16 of the rake face 1. The first convex portion 41 is formed in a protrusion shape in a manner that forms a part of a sphere. The surface (protrusion surface) of the first convex portion 41 is in a convex curved surface shape, specifically, in a convex spherical surface shape in a manner that forms a part of a spherical surface.

[0088] exist Figure 5 In the plan view shown, the first convex portion 41 is located on the bisector B. Also, in the plan view, the first convex portion 41 is arranged to overlap with the center O of the radius of curvature of the blade corner 3a. More specifically, in the present embodiment, in the plan view, the top 41a located at the upper end of the first convex portion 41 overlaps with the center O of the radius of curvature of the blade corner 3a.

[0089] like Figure 6 As shown, the top 41a of the first protrusion 41 is arranged above the reference plane Pr which passes through the uppermost corner 3a of the cutting edge 3 and extends in a direction perpendicular to the vertical direction. That is, the first protrusion 41 protrudes upward from the cutting edge 3.

[0090] And, if Figure 6 As shown in FIG. 1 , the front end of the first protrusion 41 is located below the blade corner 3a. Figure 5 And express Figure 5 Section VII-VII Figure 7 As shown, the two end portions in the left-right direction of the first convex portion 41 (at Figure 7 The left end portion of the first protrusion 41 in the middle is located below the blade corner 3a.

[0091] like Figure 4and Figure 5 As shown, the second convex portion 42 protrudes upward from the rake face 1 and is arranged on the rear side of the first convex portion 41. In detail, the second convex portion 42 includes a portion arranged on the inclined surface 16 of the rake face 1. The second convex portion 42 extends toward the front side as it moves away from the bisector B in the left-right direction. The second convex portion 42 is formed in a rib shape. The surface of the second convex portion 42 is convexly curved.

[0092] The second convex portions 42 are provided as a pair on the left side (-X side) and the right side (+X side) of the bisector B. The pair of second convex portions 42 are formed in a bilaterally symmetrical shape with the bisector B as a symmetry axis. Therefore, the following mainly describes one of the pair of second convex portions 42.

[0093] The inner (center) end of the second convex portion 42 in the left-right direction is located on the bisector B. Figure 5 In the plan view shown, the width dimension of the inner portion of the second convex portion 42 increases as it moves outward from the bisector B. In addition, in the plan view, the width dimension of the outer portion of the second convex portion 42 decreases as it moves outward.

[0094] And, in Figure 5 In the plan view shown, the second convex portion 42 includes a portion located outside the center O of the curvature radius of the blade corner 3a in the left-right direction (the outer end in the left-right direction) and a portion located behind the center O (the inner end in the left-right direction). The second convex portion 42 is arranged to surround the center O of the curvature radius of the blade corner 3a and the first convex portion 41 from the outside and the rear side in the left-right direction.

[0095] Figure 5 The reference numeral L indicated by a straight line of a single dotted line in FIG. 4 represents the direction in which the ridgeline 42a of the second convex portion 42 extends. That is, the ridgeline 42a of the second convex portion 42 extends in a straight line. Figure 5 In the plan view shown, an angle α formed between the ridge line 42 a of the second convex portion 42 and the bisector B is, for example, not less than 30° and not more than 60°.

[0096] like Figure 4 As shown, the ridgeline 42a of the second convex portion 42 extends upward from the outer end portion toward the inner end portion in the left-right direction of the second convex portion 42 along the direction along which the ridgeline 42a extends. That is, the second convex portion 42 protrudes upward more as it approaches the bisector B along the direction along which the ridgeline 42a extends.

[0097] like Figure 6As shown, the second convex portion 42 has a portion located above a reference plane Pr extending in a direction perpendicular to the vertical direction through the uppermost corner 3a of the cutting edge 3. That is, the second convex portion 42 protrudes upward from the cutting edge 3.

[0098] like Figure 6 and Figure 7 As shown in FIG. 1 , the second convex portion 42 has a portion disposed above the top portion 41 a located at the uppermost side of the first convex portion 41. That is, the second convex portion 42 protrudes upwardly more than the first convex portion 41.

[0099] like Figure 4 and Figure 5 As shown, the third protrusion 43 protrudes upward from the front cutting edge 1 and is arranged on the front side of the first protrusion 41. In detail, the third protrusion 43 is arranged on the inclined surface 16 in the front cutting edge 1. The third protrusion 43 is formed in a protrusion shape in a manner that forms a part of a sphere. The surface (protrusion surface) of the third protrusion 43 is in a convex curved surface shape, specifically, it is formed in a convex spherical surface shape in a manner that forms a part of a spherical surface. In the present embodiment, the curvature radius of the protrusion surface (convex curved surface) of the third protrusion 43 is smaller than the curvature radius of the protrusion surface (convex curved surface) of the first protrusion 41.

[0100] exist Figure 5 In the plan view shown, the third convex portion 43 is located on the bisector B. Also, in the plan view, the third convex portion 43 is arranged on the front side of the center O of the radius of curvature of the edge corner 3 a.

[0101] like Figure 6 As shown, the third convex portion 43 is disposed entirely below a reference plane Pr extending through the edge corner 3a in a direction perpendicular to the vertical direction. That is, the third convex portion 43 is located below at least the edge corner 3a of the cutting edge 3.

[0102] Furthermore, the top 43a located at the uppermost side of the third convex portion 43 is located below the top 41a located at the uppermost side of the first convex portion 41. That is, the height of the third convex portion 43 in the vertical direction is lower than the height of the first convex portion 41 in the vertical direction.

[0103] like Figures 4 to 6 As shown, the chip breaker wall 44 is arranged on the rear side of the second protrusion 42 and protrudes upwardly than the second protrusion 42. The chip breaker wall 44 has a wall surface located on the upper side of the second protrusion 42 and facing the front side and the left and right directions. In this embodiment, the chip breaker wall 44 has a conical surface 44a arranged adjacent to the rear side of the second protrusion 42 and a wavy surface 44b arranged on the rear side of the conical surface 44a.

[0104] The conical surface portion 44a is in the shape of a conical surface convex toward the front side. The conical surface portion 44a is in the shape of a convex curved surface toward the front side, the left side, and the right side, and extends along the circumferential direction of the blade. The conical surface portion 44a is formed so as to decrease in diameter as it goes upward.

[0105] like Figure 5 As shown in the figure, the wavy surface portion 44b is connected to the outer end portion of the conical surface portion 44a in the left-right direction, and extends toward the outer side in the left-right direction as it goes toward the rear side. The wavy surface portion 44b is provided as a pair on the left side (-X side) and the right side (+X side) of the bisector B. The pair of wavy surface portions 44b are formed into a left-right symmetrical shape with respect to the bisector B as a symmetry axis. Therefore, the following mainly describes any one of the pair of wavy surface portions 44b.

[0106] The wavy surface portion 44b is formed in a wave-like shape (in a meandering manner) so as to alternately move inward (centrally) and outward in the left-right direction as it moves away from the connection portion with the conical surface portion 44a along the direction in which the wavy surface portion 44b extends. The wavy surface portion 44b is inclined so as to approach the bisector B as it moves upward.

[0107] like Figure 4 and Figure 5 As shown, the chip breaker 4 further includes a valley portion 45 disposed between the first convex portion 41 and the second convex portion 42. The valley portion 45 is located at the boundary portion between the first convex portion 41 and the second convex portion 42 and is in the shape of a groove that is concave downward. Figure 5 As shown, the valley portion 45 extends toward the front side as it moves away from the bisector B in the left-right direction. The direction in which the valley portion 45 extends is substantially the same as the direction in which the ridgeline 42 a of the second convex portion 42 extends.

[0108] The valleys 45 are provided as a pair on the left side (-X side) and the right side (+X side) of the bisector B. The pair of valleys 45 are formed in a bilaterally symmetrical shape with the bisector B as a symmetry axis. Therefore, the following mainly describes one of the pair of valleys 45.

[0109] The inner (central) end of the valley portion 45 in the left-right direction is located on the bisector B. The outer end of the valley portion 45 in the left-right direction is connected to the inclined surface 16 of the rake face 1. Figure 6 to Figure 8 As shown, the position of the valley bottom (groove bottom) of the valley portion 45 in the vertical direction becomes lower as it moves from the inner end portion in the left-right direction toward the outer end portion along the direction in which the valley portion 45 extends.

[0110] In detail, Figure 6 and Figure 7 As shown, in the inner part of the valley 45 in the left-right direction, the valley bottom of the valley 45 is located above the reference plane Pr, which extends in a direction perpendicular to the up-down direction through the cutting edge 3. Figure 8As shown, at the outer portion (particularly, the outer end portion) of the valley portion 45 in the left-right direction, the valley bottom of the valley portion 45 is located below a reference plane Pr (that is, below the cutting edge 3 ) not shown.

[0111] 〔Mounting hole〕

[0112] like Figure 1 and Figure 2 As shown, the mounting hole 5 penetrates the cutting tool 10 in the axial direction of the blade and opens on a pair of plate surfaces (front and back) of the cutting tool 10. The mounting hole 5 is a circular hole centered on the blade center axis C. Although not particularly shown, a clamping member or a clamping screw, etc., for fixing the cutting tool 10 to the blade mounting seat of the tool holder is inserted into the mounting hole 5.

[0113] [Effects of this embodiment]

[0114] In the cutting tool 10 of the present embodiment described above, for example, during high feed (high feed) with a large feed amount, the chips generated by the cutting edge 3 contact the first convex portion 41 and the second convex portion 42 of the chip breaker 4. That is, the chips are compressed and curled in a manner that they are supported at two points by the two convex portions 41 and 42 arranged in the front-back direction and clamped by these convex portions 41 and 42. Therefore, thick chips can be stably curled, thereby maintaining good chip handling properties.

[0115] Specifically, the second convex portion 42 extends toward the front side as it moves away from the bisector B in the left-right direction. The direction in which the second convex portion 42 extends is substantially the same as the direction in which the chips generated by the cutting edge 3 flow out on the rake face 1, so that the chips are guided to the outflow direction by the second convex portion 42 and stably curled by the two convex portions 41, 42. Therefore, the chip handling performance is more stable.

[0116] Furthermore, during low feed with a small feed amount, the chips generated by the cutting edge 3 come into contact with the third protrusion 43 located on the front side of the chip breaker 4. Therefore, the thin chips are prevented from extending and broken stably.

[0117] Specifically, the height of the third convex portion 43 in the vertical direction is lower than the height of the first convex portion 41 in the vertical direction, that is, the protrusion amount of the third convex portion 43 from the rake face 1 is small. Therefore, it is possible to suppress excessive curling of the chips contacting the third convex portion 43, thereby suppressing the chips from contacting the machined surface of the workpiece. As a result, the machined surface accuracy can be well maintained.

[0118] As described above, according to the present embodiment, regardless of the cutting amount and the like, chip disposability can be maintained well and the machined surface accuracy can be stably improved.

[0119] Furthermore, in the present embodiment, the second convex portion 42 protrudes upward more than the first convex portion 41 .

[0120] At this time, the chips flowing out while being supported at two points by the first convex portion 41 and the second convex portion 42 are wound into a spiral shape by the height difference between the convex portions 41 and 42 and are stably wound, so that the chip handling performance can be improved more stably.

[0121] Furthermore, in the present embodiment, the chip breaker 4 includes a chip breaker wall 44 which is disposed on the rear side of the second protrusion 42 and protrudes upward from the second protrusion 42 .

[0122] At this time, the chips that have passed over the second convex portion 42 to the rear side are stably processed by contacting the chip breaker wall 44. In the present embodiment, the chips that have passed over the second convex portion 42 are well processed by contacting the conical surface portion 44a.

[0123] Furthermore, in the present embodiment, the third protrusion 43 is located below at least the corner 3 a of the cutting edge 3 .

[0124] At this time, the third convex portion 43 is arranged below the cutting edge 3a, so that during low cutting, the chips generated by the cutting edge 3a and contacting the third convex portion 43 are stably prevented from curling excessively. This can stably improve the machined surface accuracy.

[0125] Furthermore, in the present embodiment, the third convex portion 43 is located on the front side of the center O of the curvature radius of the blade corner 3 a in a plan view.

[0126] At this time, the chips generated by the cutting edge 3a during low cutting or the like can stably contact the third convex portion 43. The chip handling performance of the third convex portion 43 can be more stably exerted.

[0127] Furthermore, in the present embodiment, the first convex portion 41 overlaps with the center O of the radius of curvature of the blade corner 3 a in a plan view.

[0128] At this time, during cutting, chips generated near the boundary between the corner 3a and the straight edge 3b of the cutting edge 3 or the corner 3a can stably contact the first convex portion 41. The first convex portion 41 can more stably exert its chip handling performance.

[0129] Furthermore, in this embodiment, Figure 5 In the plan view shown, an angle α formed between a ridgeline 42 a of the second convex portion 42 and the bisector B is greater than or equal to 30° and less than or equal to 60°.

[0130] If the above-mentioned angle α is greater than 30° and less than 60°, regardless of the opening angle of the cutting edge 3 in the plan view (the angle formed between a pair of straight edges 3b) or the tool posture during cutting, the second protrusion 42 can more stably perform the chip processing performance.

[0131] If the angle α is less than 30° or exceeds 60°, the chip outflow direction and the extending direction of the second convex portion 42 may greatly differ depending on the opening angle of the cutting edge 3 or the tool posture during cutting, which may affect chip handling performance.

[0132] Furthermore, in the present embodiment, at the outer portion (particularly, the outer end portion) of the valley portion 45 in the left-right direction, the valley bottom (groove bottom) of the valley portion 45 is located below the cutting edge 3 .

[0133] At this time, the depth of the valley 45 between the first convex portion 41 and the second convex portion 42, which is the outer portion in the left-right direction where the chips start to contact, can be ensured to be large, so that the chip curling function under the two-point support of the two convex portions 41 and 42 can be more stable. In addition, even when the convex portions 41 and 42 have begun to wear, it is easy to maintain the curling function based on the two-point support.

[0134] [Other structures included in the present invention]

[0135] The present invention is not limited to the above-described embodiment, and for example, structural changes and the like may be made as described below without departing from the gist of the present invention.

[0136] In the above embodiment, the example in which the rake angle of the land 15 of the rake face 1 is a positive angle is cited, but the present invention is not limited thereto. The rake angle of the land 15 may be 0° or a negative angle. Furthermore, the land 15 may not be provided on the rake face 1.

[0137] In the above embodiment, an example in which the clearance angle of the flank face 2 is 0° is cited, but it is not limited thereto. Although not particularly illustrated, the flank face 2 may also be inclined inwardly in the radial direction of the blade as it moves away from the cutting edge 3 along the axial direction of the blade. At this time, the flank face 2 is given a predetermined clearance angle.

[0138] In the above embodiment, the cutting tool 10 is an example of a double-sided type with a front-back inversion symmetry, but the present invention is not limited thereto. The cutting tool 10 may be a single-sided type without a front-back inversion symmetry.

[0139] In the above embodiment, an example in which the cutting tool 10 is formed by a single component made of cemented carbide is cited, but it is not limited to this. Although not specifically shown in the figure, the cutting tool 10 may also have, for example, a base metal portion in the shape of a polygonal plate and a blade portion fixed to a recessed portion located at a corner of the base metal portion. In this case, the base metal portion is made of, for example, cemented carbide, and the blade portion is made of, for example, a cBN (cubic boron nitride: cubic boron nitride) sintered body or a diamond sintered body (Polycrystalline diamond, PCD). The blade portion is provided with a front cutting face 1, a back cutting face 2, a cutting edge 3 and a chip breaker 4. The base metal portion is provided with a mounting hole 5.

[0140] In the above embodiment, the example of the cutting tool 10 being a cutting insert is cited, but the invention is not limited thereto. The cutting tool of the present invention only needs to have a rake face 1, a flank face 2, a cutting edge 3 and a chip breaker 4, and may be, for example, a replaceable head component of an indexable insert turning tool. Alternatively, the cutting tool may be a solid type (integrated) turning tool, etc.

[0141] The present invention can combine the structures described in the above embodiments and modifications, and can add, omit, replace and make other changes to the structures without departing from the gist of the present invention. Furthermore, the present invention is not limited to the above embodiments, but is limited only by the claims.

[0142] Industrial Applicability

[0143] According to the cutting tool of the present invention, regardless of the cutting amount and the like, it is possible to maintain good chip disposability and stably improve the machined surface accuracy. Therefore, the cutting tool has industrial applicability.

[0144] Description of Reference Numerals

[0145] 1 Rake face

[0146] 2. Flank surface

[0147] 3 cutting edges

[0148] 3a blade angle

[0149] 3b straight edge

[0150] 4 Chip breaker

[0151] 10Cutting Tools

[0152] 41 first convex part

[0153] 42 second convex part

[0154] 42a(L) Edge

[0155] 43 The third convex part

[0156] 44 chip breaking wall

[0157] B Bisector

[0158] O The center of the curvature radius of the blade angle

[0159] α angle

Claims

1. A cutting tool comprising: Rake face; Flank surface; a cutting edge disposed on a ridge connecting the rake face and the flank face, the cutting edge being V-shaped in a plan view of the rake face viewed from the front; and A chip breaker is arranged on the front cutting edge. When the direction in which the bisector of the cutting edge extends in the plan view is set as the front-back direction, the direction orthogonal to the bisector in the plan view is set as the left-right direction, and the direction orthogonal to the front-back direction and the left-right direction is set as the up-down direction, The chip breaker has: A first convex portion protrudes upward from the front blade surface; a second convex portion that protrudes upward from the rake face and is disposed on the rear side of the first convex portion and extends toward the front side as it moves away from the bisector in the left-right direction; and A third convex portion protrudes upward from the front blade surface and is arranged on the front side of the first convex portion. The first convex portion and the second convex portion protrude upwardly from the cutting edge. A height of the third protrusion in the up-down direction is lower than a height of the first protrusion in the up-down direction.

2. The cutting tool according to claim 1, wherein: The second convex portion protrudes upward more than the first convex portion.

3. The cutting tool according to claim 1 or 2, wherein: The chip breaker includes a chip breaking wall that is disposed on the rear side of the second protrusion and protrudes upward from the second protrusion.

4. The cutting tool according to claim 1 or 2, wherein: The cutting edge has: The blade angle is convex and curved; and A pair of straight blades are connected to both ends of the blade corner and extend in straight lines respectively. The third protrusion is located below at least the edge corner of the cutting edge.

5. The cutting tool according to claim 4, wherein: The third convex portion is located on the front side of the center of the radius of curvature of the blade corner in the plan view.

6. The cutting tool according to claim 4, wherein: The first convex portion overlaps with the center of the radius of curvature of the edge corner in the plan view.

7. The cutting tool according to claim 1 or 2, wherein: In the plan view, an angle between a ridgeline formed on the second convex portion and the bisector is greater than or equal to 30° and less than or equal to 60°.

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