Cutting insert and indexable insert type rotary cutting tool
By setting different rear angle relationships and area designs between the main cutting edge and the light-tightening edge in the cutting insert, the problem of insufficient strength and wear resistance of the cutting insert is solved, and high efficiency and long-life cutting processing is achieved.
Patent Information
- Application Number
- CN202480005008.9
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Priority Date
- 2023-03-29
- Filing Date
- 2024-03-28
- Publication Date
- 2025-07-04
AI Technical Summary
It is difficult for existing cutting inserts to take into account the strength of the main cutting edge and the wear resistance of the light-tightening blade. At the same time, the binding nature of the cutting insert on the bracket is insufficient, resulting in limited processing efficiency and life.
A polygonal plate-shaped cutting insert is designed. The rear angle of the main cutting edge is smaller than the rear angle of the light-finishing blade. By adjusting the size relationship of the rear angle, the strength of the main cutting edge and the wear resistance of the light-finishing blade are ensured, while the area of the light-finishing blade is increased to improve the restraint on the bracket.
It achieves the balance between the strength of the main cutting edge and the wear resistance of the light-tightening blade, improves the life and processing efficiency of the cutting insert, and enhances the constraints on the bracket, ensuring high-quality machining surfaces.
Smart Images
Figure CN120265409A_ABST
Abstract
Description
Technical Field
[0001] The present invention relates to cutting inserts and indexable insert type rotary cutting tools.
[0002] This application claims priority based on Japanese Patent Application No. 2023-053255 filed on March 29, 2023, and incorporates its content herein. Background Art
[0003] Conventionally, an indexable insert type rotary cutting tool having a cutting insert has been known. Patent Document 1 discloses a cutting insert capable of improving the rigidity of the edge angle and improving the machining efficiency.
[0004] Patent Document 1: Japanese Unexamined Patent Application Publication No. 2022-151053 (A)
[0005] In the cutting insert described in Patent Document 1, the clearance angle with respect to the main cutting edge and the clearance angle with respect to the finishing edge, that is, the secondary cutting edge, are the same angle. For the finishing edge, it is important to suppress flank wear, and for the main cutting edge, cutting edge strength is important. However, if the clearance angle is increased to suppress flank wear of the finishing edge, the clearance angle of the main cutting edge becomes larger and the cutting edge strength decreases. In the cutting insert described in Patent Document 1, there is a problem that it is impossible to balance the strength of the main cutting edge and the wear resistance of the finishing edge.
[0006] In addition, the cutting insert described in Patent Document 1 mounts the flank surface adjacent to the main cutting edge as a restraining surface on the holder. In this case, the force applied to the main cutting edge during cutting acts in a direction perpendicular to the above-mentioned restraining surface, so there is a problem that it is difficult to suppress the movement of the cutting insert in a direction parallel to the restraining surface. Summary of the Invention
[0007] (1) According to one aspect of the present invention, there is provided a cutting insert which is in the shape of a polygonal plate. The cutting insert includes: a rake face constituting one of a pair of polygonal faces; a seating face constituting the other of the pair of polygonal faces; a flank connecting the rake face and the seating face; and a mounting hole that opens on the rake face and the seating face and penetrates the cutting insert in the thickness direction. A cutting edge portion is provided on the intersection ridge line between the rake face and the flank. The cutting edge portion includes a blade angle, a main cutting edge connected to the blade angle, a convex curved edge connected to the main cutting edge, and a finishing edge connected to the convex curved edge. The flank has a first flank connected to the main cutting edge, a second flank connected to the finishing edge, and a boundary region connected to the convex curved edge. In a side view of observing the flank from the front, the first flank and the second flank are separated on the left and right sides by the boundary region extending between the rake face and the seating face. The clearance angle θ1 of the main cutting edge and the clearance angle θ2 of the finishing edge satisfy the relationship θ1 < θ2. When the end point on the rake face side of the boundary region is set as end point P and the center line of the mounting hole is set as O1, in the side view, the end point P is located at a position farther from the blade angle than the center line O1.
[0008] (2) In (1), it may also be configured that: when the end point on the seating face side of the boundary region is set as end point Q, in the side view, the end point Q is located at a position closer to the blade angle than the center line O1.
[0009] (3) In (1) or (2), it may also be configured that: the clearance angles θ1, θ2 satisfy: 8° ≤ θ1 ≤ 18°, and 12° ≤ θ2 ≤ 25°.
[0010] (4) In any one of (1) to (3), it may also be configured that: in the side view, the angle θ3 formed by the straight line L connecting the end point P and the end point Q and the seating face satisfies: 45° ≤ θ3 ≤ 85°.
[0011] (5) In any one of (1) to (4), it may also be configured that: in a top view of observing the rake face from the front, the main cutting edge is a straight cutting edge. When the cutting edge length of the main cutting edge is set as L1 and the in - circle diameter of the rake face is set as D1, it satisfies: 0.35×D1 ≤ L1 ≤ 0.60×D1.
[0012] (6) A indexable insert type rotary cutting tool includes: the cutting insert according to any one of (1) to (5); and a holder that can detachably mount the cutting insert and rotate around a rotation axis. The holder has a blade seat that contacts the flank and the seating face of the cutting insert with respect to the finishing edge.
[0013] (7) In (6), it can also be configured such that the lowest point of the tool is located on the finishing edge, and the cutting-in angle K satisfies: 5° ≤ K ≤ 25°.
[0014] According to one aspect of the present invention, there is provided a cutting insert and an indexable insert type rotary cutting tool including the above cutting insert. The cutting insert can balance the strength of the main cutting edge and the suppression of flank wear of the finishing edge, and also has excellent restraint on the holder. BRIEF DESCRIPTION OF THE DRAWINGS
[0015] Figure 1 is a perspective view showing the cutting insert of the embodiment.
[0016] Figure 2 is showing Figure 1 a top view of the rake face structure of the cutting insert shown.
[0017] Figure 3 is a side view showing the side structure of the cutting insert.
[0018] Figure 4A is a cross-sectional view of the cutting insert along Figure 2 the line IVa-IVa.
[0019] Figure 4B is a cross-sectional view of the cutting insert along Figure 2 the line IVb-IVb.
[0020] Figure 5 is a side view of the indexable insert type rotary cutting tool.
[0021] Figure 6 is a perspective view of the indexable insert type rotary cutting tool.
[0022] Figure 7 is a perspective view showing the holder in a state where the cutting insert 1 is removed.
[0023] Figure 8 is an explanatory view showing the change in the restraint state of the cutting insert caused by the change over time of the holder. The left side shows the cutting insert restrained by a new holder, and the right side shows the cutting insert restrained by a worn holder after use over time.
[0024] Figure 9 is an explanatory view showing the change in the restraint position.
[0025] Figure 10 is a perspective view showing the cutting insert of the modified example.
[0026] Figure 11 is showing Figure 10 a top view of the rake face structure of the cutting insert shown.
[0027] Figure 12 is a side view showing Figure 10 the side structure of the cutting blade shown. Detailed Embodiment
[0028] Hereinafter, embodiments of applying the present invention will be described in detail with reference to the accompanying drawings. It should be noted that in the accompanying drawings used in the following description, in order to facilitate understanding of the characteristic parts, sometimes non-characteristic parts are omitted for convenience.
[0029] Figure 1 is a perspective view showing the cutting blade 1 of the embodiment. Figure 2 is a top view showing Figure 1 the structure of the rake face 2 of the cutting blade 1 shown, which is a top view of observing the rake face 2 from the front. Figure 3 is a side view showing the structure of the side face 10 of the cutting blade 1, which is a side view of observing the side face from the front.
[0030] The cutting blade 1 is a polygonal plate shape (quadrilateral plate shape in this embodiment) that is rotationally symmetric with respect to the center line O1 extending in the thickness direction. In this embodiment, the center line O1 is the central axis of the mounting hole 7 that penetrates the cutting blade 1 in the thickness direction.
[0031] It should be noted that in the following description, sometimes the direction along the center line O1 is simply referred to as the thickness direction. In addition, sometimes the direction orthogonal to the center line O1 is simply referred to as the radial direction. Similarly, sometimes the circumferential direction around the axis centered on the center line O1 is simply referred to as the circumferential direction.
[0032] The cutting blade 1 includes: a rake face 2 that constitutes one of a pair of polygonal faces; a seating face 3 that constitutes the other of the pair of polygonal faces; a side face 10 that connects the rake face 2 and the seating face 3; and a mounting hole 7 for mounting on a holder. As Figure 2 shown, the rake face 2 and the seating face 3 are formed in a substantially quadrilateral shape. The seating face 3 is included inside the projection area of the rake face 2 in the thickness direction. The side face 10 has two side faces 10A connected to the long side of the rake face 2 and two side faces 10B connected to the short side of the rake face 2.
[0033] As described later in Figure 5 and Figure 6 shown, the cutting blade 1 can be detachably mounted on the front end portion of the holder 31 by a clamping screw 38. Therefore, a mounting hole 7 that penetrates the cutting blade 1 in the thickness direction is formed in the rake face 2 and the seating face 3, and the clamping screw 38 is inserted into the mounting hole 7. The mounting hole 7 extends along the center line O1 of the cutting blade 1. The mounting hole 7 is a tapered through hole centered on the center line O1.
[0034] A cutting edge portion 20 is provided on the intersection ridge line between the front cutting face 2 and the side face 10B connected to the short side of the front cutting face 2.
[0035] The cutting edge portion 20 includes a cutting edge angle 24, a main cutting edge 21 connected to the cutting edge angle 24, and a finishing edge 22 connected to the main cutting edge 21. In the case of the present embodiment, the cutting edge portion 20 has a convex curved edge 23 connecting the main cutting edge 21 and the finishing edge 22. In the plan view of the front cutting face 2, the cutting edge angle 24, the main cutting edge 21, the convex curved edge 23, and the finishing edge 22 are arranged in order in the right-turn direction (clockwise direction). In addition, the front cutting face 2 may include a reference plane 2a parallel to the seating surface 3.
[0036] In the cutting insert 1 of the present embodiment, two cutting edge portions 20 formed by the cutting edge angle 24, the main cutting edge 21, the convex curved edge 23, and the finishing edge 22 are provided at intervals of 180° in the circumferential direction centered on the center line O1. The two cutting edge portions 20 are arranged rotationally symmetrically about the center line O1. The pair of cutting edge portions 20 are separated from each other with the long side of the front cutting face 2 interposed therebetween.
[0037] The main cutting edge 21 is located on the short side of the front cutting face 2 and extends linearly in the plan view of the front cutting face 2. The main cutting edge 21 is the longest among the cutting edges constituting the cutting edge portion 20. In the state where the cutting insert 1 is mounted on the holder 31 (refer to Figure 5 and Figure 6 ), the main cutting edge 21 faces the rotation direction TD side of the holder 31 and faces the workpiece to be cut.
[0038] In this specification, the so-called "linear" cutting edge includes not only a complete straight line but also a substantially straight line within a certain error range. If specifically exemplified, in the case of a cutting insert with a main cutting edge 21 having a length of about 3 mm, a gentle arc shape with a radius of curvature exceeding 50 mm or a curved shape meandering with a meandering width of 0.05 mm or less is also included in the "linear" in this specification.
[0039] The cutting edge angle 24 is connected to the main cutting edge 21 and is located at the corner portion of the front cutting face 2. The cutting edge angle 24 has an arc shape in the Figure 2 shown plan view. On the other hand, the main cutting edge 21 extends linearly. Therefore, the boundary between the cutting edge angle 24 and the main cutting edge 21 is determined by the boundary between the linear shape portion and the arc shape portion in the cutting edge portion 20.
[0040] The finishing edge 22 is located on the side opposite to the edge angle 24 with respect to the main cutting edge 21. The finishing edge 22 is a linear cutting edge extending along a direction intersecting with the main cutting edge 21. The finishing edge 22 extends obliquely with respect to the extending direction of the main cutting edge 21 in such a manner that it approaches the center line O1 as it moves away from the main cutting edge 21. Thus, the boundary portion between the main cutting edge 21 and the finishing edge 22 forms a shape protruding outward. In the case of the present embodiment, a convex curve edge 23 is provided between the main cutting edge 21 and the finishing edge 22. The convex curve edge 23 can be an arc shape or a curve shape other than an arc.
[0041] In addition, the convex curve edge 23 can also be a pseudo-arc formed by a continuous plurality of short straight lines.
[0042] Since the cutting insert 1 in the present embodiment is a positive cutting insert, as Figure 1 and Figure 3 shown, the side surface 10B connected to the cutting edge portion 20, that is, the flank of the cutting edge portion 20 becomes a inclined surface substantially along the clearance angle. The flank of the cutting edge portion 20 connects the rake face 2 and the seating surface 3.
[0043] The flank of the cutting edge portion 20, that is, the side surface 10B has a first side surface 11A connected to the main cutting edge 21 and a second side surface 11B connected to the finishing edge 22. In a side view, the first side surface 11A and the second side surface 11B are separated on the left and right sides by a boundary region 11C extending between the rake face 2 and the seating surface 3. In the present embodiment, the boundary region 11C is connected to the convex curve edge 23 on the rake face 2 side and is connected to a ridge line 3a which is a part of the seating surface 3 on the seating surface 3 side. In the present embodiment, although the convex curve edge 23 and the ridge line 3a have the same shape in the top view of the rake face 2, the shapes of the convex curve edge 23 and the ridge line 3a can also be different. For example, the radius of curvature of the ridge line 3a can be smaller than the radius of curvature of the convex curve edge 23.
[0044] The boundary region 11C is the boundary ridge line portion between the first side surface 11A and the second side surface 11B. In the case of the present embodiment, the boundary region 11C is formed into a relatively gentle convex surface shape, thereby smoothly connecting the first side surface 11A and the second side surface 11B. Therefore, in a side view, the width of the boundary region 11C is relatively large. In addition, the convex curve edge 23 connected to the boundary region 11C also has a relatively gentle convex curve shape.
[0045] It is also possible to make the width of the boundary region 11C narrower and make the convex curve edge 23 into a sharper convex curve shape. That is, the widths of the convex curve edge 23 and the boundary region 11C are not particularly limited and can be appropriately adjusted based on the machining surface state of the workpiece to be machined, etc.
[0046] Here, Figure 4A is along theFigure 2 Cross-sectional view along the IVa-IVa line. Figure 4B is a cross-sectional view of the cutting insert 1 along Figure 2 the IVb-IVb line. The IVa-IVa line is orthogonal to the main cutting edge 21, and the IVb-IVb line is orthogonal to the wiper edge 22.
[0047] Figure 4A As shown, θ1 is the clearance angle of the main cutting edge 21, Figure 4B and as shown, θ2 is the clearance angle of the wiper edge 22. As shown in these figures, the clearance angle θ2 of the wiper edge 22 is greater than the clearance angle θ1 of the main cutting edge 21. That is, the clearance angle θ1 of the main cutting edge 21 and the clearance angle θ2 of the wiper edge 22 satisfy the relationship θ1 < θ2.
[0048] By setting the clearance angles θ1 of the main cutting edge 21 and θ2 of the wiper edge 22 to different angles, the clearance angles θ1 and θ2 can be designed separately. Thus, by setting the clearance angle θ1 of the main cutting edge 21 to be small, the tip strength of the main cutting edge 21 can be ensured. In addition, by setting the clearance angle θ2 of the wiper edge 22 to be large, wear of the flank face of the wiper edge 22, that is, the second side face 11B, can be suppressed. It is possible to balance the tip strength of the main cutting edge 21 and the suppression of flank face wear of the wiper edge 22, so a long-life cutting insert 1 can be obtained.
[0049] By stipulating the magnitude relationship of the clearance angles θ1, θ2 as described above, as Figure 3 shown, the boundary region 11C separating the first side face 11A and the second side face 11B extends obliquely with respect to the center line O1 in the side face 10B. Thus, the width of the first side face 11A in the direction along the short side of the rake face 2 gradually narrows from the rake face 2 toward the seating face 3. On the other hand, the width of the second side face 11B in the direction along the short side of the rake face 2 gradually widens from the rake face 2 toward the seating face 3.
[0050] In the present embodiment, the clearance angles θ1, θ2 preferably satisfy 8° ≤ θ1 ≤ 18° and 12° ≤ θ2 ≤ 25°.
[0051] By setting the clearance angle θ1 within the above range, while avoiding contact between the flank face in the main cutting edge 21 and the surface of the workpiece to be cut, the tip strength of the main cutting edge 21 can be ensured. Thus, high-efficiency machining is facilitated. The clearance angle θ1 is more preferably 9° or more. The clearance angle θ1 is more preferably 15° or less.
[0052] By setting the clearance angle θ2 within the above range, wear of the flank face of the wiper edge 22 can be suppressed, and a high-quality machined surface can be obtained. In addition, the tip and overall strength of the cutting insert 1 can be ensured, so chipping of the cutting insert 1 can be suppressed, and the life can be extended. The clearance angle θ2 is more preferably 15° or more. The clearance angle θ2 is more preferably 20° or less.
[0053] In the present embodiment, as Figure 3 shown, when the end point on the rake face 2 side of the boundary region 11C that extends obliquely with respect to the center line O1 is set as the end point P, and the end point on the seating surface 3 side is set as the end point Q, in the side view of the side surface 10B, the end point P is located at a position farther from the edge angle 24 than the center line O1.
[0054] In the present embodiment, the end point P is defined as the center point of the cutting edge length of the convex curved edge 23. In addition, the end point Q is defined as the center point of the edge length of the ridge line 3a.
[0055] In the side view of the side surface 10B, the end point P is located at a position farther from the edge angle 24 than the center line O1. Thus, the intersection region of the boundary region 11C and the rake face 2, that is, the entire convex curved edge 23 is located at a position farther from the edge angle 24 than the center line O1. Thus, the linear main cutting edge 21 has a structure that extends to a position farther from the edge angle 24 than the center line O1. The linear main cutting edge 21 has a larger range of cutting into the workpiece compared with the arc-shaped cutting edge, and the heat generated by the friction with the workpiece is dispersed over a wider range in the length direction of the main cutting edge 21. Therefore, compared with the arc-shaped main cutting edge, local temperature rise is not likely to occur, and the effect of suppressing thermal wear of the rake face and the flank face can be obtained. In the present embodiment, by the above structure, the length of the linear main cutting edge 21 is increased, so that the temperature rise during cutting can be further suppressed, and the wear of the rake face and the flank face can be further reduced.
[0056] Figure 5 and Figure 6 FIGS. are perspective views showing the structure of the indexable insert type rotary cutting tool 30 having a plurality of cutting inserts 1 and a holder 31 to which these cutting inserts 1 are detachably mounted. Figure 7 FIG. is a perspective view showing the holder 31 in a state where the cutting insert 1 is removed.
[0057] The indexable insert type rotary cutting tool 30 performs cutting by rotating the holder 31 about the rotation axis J1 in the rotation direction TD. The indexable insert type rotary cutting tool 30 has a holder 31 that rotates about the rotation axis J1 and three cutting inserts 1 mounted on the holder 31.
[0058] As Figure 7 shown, three blade seats 33 are provided at the front end of the holder 31. The blade seat 33 has a seat bottom surface 34 and two seat wall surfaces 35, 36.
[0059] The bottom surface 34 of the mounting seat is rectangular in shape with an area approximately equal to the seating surface 3 of the cutting blade 1, and faces the rotational direction TD. The mounting seat wall surface 35 is the surface on the front end side facing the direction of the rotational axis J1, and extends in the radial direction of the support 31 along the short side of the bottom surface 34 of the mounting seat. The mounting seat wall surface 36 is the surface facing the radially outer side of the support 31, and extends in the direction of the rotational axis J1 along the long side of the bottom surface 34 of the mounting seat. A screw hole 37 is formed approximately at the center of the bottom surface 34 of the mounting seat.
[0060] The bottom surface 34 of the mounting seat is in opposed contact with the seating surface 3 of the cutting blade 1. The mounting seat wall surface 35 is in opposed contact with the side surface 10B of the cutting blade 1. The mounting seat wall surface 36 is in opposed contact with the side surface 10A of the cutting blade 1.
[0061] The cutting blade 1 is mounted on the blade mounting seat 33 of the support 31 using a clamping screw 38. The cutting blade 1 is mounted on the support 31 by the clamping screw 38 inserted into the mounting hole 7 and screwed into the screw hole 37 formed at the center of the bottom surface 34 of the mounting seat.
[0062] In the cutting blade 1 of the present embodiment, the seating surface 3 is closely attached to the bottom surface 34 of the mounting seat of the support 31, and the side surfaces 10A and 10B are respectively in contact with the mounting seat wall surfaces 36 and 35 to be fixed. Further, by screwing the clamping screw 38 into the screw hole 37, the seating surface 3 is pressed against the bottom surface 34 of the mounting seat, and the side surfaces 10A and 10B are pressed against the mounting seat wall surfaces 36 and 35.
[0063] In the case of the present embodiment, as Figure 5 and Figure 6 shown, when the cutting blade 1 is mounted on the support 31, the second side surface 11B in the side surface 10B of the cutting blade 1 is pressed against the mounting seat wall surface 35 facing the front end side of the support 31. That is, the flank surface of the finishing edge 22, which is the second side surface 11B, becomes the restraining portion.
[0064] In the cutting blade 1, as Figure 3 shown, the clearance angle θ2 of the second side surface 11B is formed larger than the clearance angle θ1 of the first side surface 11A, so the width of the second side surface 11B in the direction orthogonal to the center line O1 becomes larger as it approaches the seating surface 3. According to this structure, compared with the case where the boundary region 11C extends parallel to the center line O1, the area of the second side surface 11B can be ensured to be larger. That is, the area of the second side surface 11B used as the restraining surface of the cutting blade 1 on the support 31 can be ensured to be larger. The contact area between the second side surface 11B and the mounting seat wall surface 35 can be increased, so the restraining force of the cutting blade 1 on the support 31 can be improved.
[0065] In addition, in the present embodiment, Figure 3The shown end point Q is preferably located on the side closer to the cutting edge angle 24 than the center line O1 (the right side in the figure). Thus, the width of the second side surface 11B in the direction orthogonal to the center line O1 can be ensured to be larger, and thus the binding force of the cutting blade 1 on the holder 31 can be further improved.
[0066] In the present embodiment, as Figure 3 shown, in the side view of the side surface 10B of the cutting blade 1, the angle θ3 formed by the straight line L connecting the end point P and the end point Q and the seating surface preferably satisfies 45° ≤ θ3 ≤ 85°.
[0067] By setting the angle θ3 to be 45° or more, the length of the linear main cutting edge 21 can be sufficiently ensured. Thus, the radial cutting depth ae can be increased, and high-efficiency machining can be achieved. In addition, since the linear main cutting edge 21 becomes longer, the temperature rise during cutting can be suppressed, and thus the life of the cutting blade 1 becomes longer. More preferably, the angle θ3 is 50° or more.
[0068] By setting the angle θ3 to be 85° or less, the area of the second side surface 11B can be ensured to be large enough, and the area of the binding portion between the cutting blade 1 and the holder 31 can be increased. The cutting blade 1 can be firmly bound, and thus high-efficiency machining is easy. The angle θ3 is more preferably 80° or less.
[0069] In the present embodiment, the main cutting edge 21 is a linear cutting edge. When the cutting edge length of the main cutting edge 21 is set to L1 and the diameter of the inscribed circle of the rake face 2 is set to D1, it is preferably satisfied that 0.35×D1 ≤ L1 ≤ 0.60×D1.
[0070] By setting the cutting edge length L1 of the main cutting edge 21 to be 0.35×D1 or more, the length of the linear main cutting edge 21 can be sufficiently ensured. Thus, the radial cutting depth ae can be increased, and high-efficiency machining can be achieved. In addition, since the linear main cutting edge 21 becomes longer, the temperature rise during cutting can be suppressed, and thus the life of the cutting blade 1 becomes longer. The cutting edge length L1 is more preferably 0.40×D1 or more.
[0071] By setting the cutting edge length L1 of the main cutting edge 21 to be 0.60×D or less, the area of the second side surface 11B can be ensured to be large enough, and the area of the binding portion between the cutting blade 1 and the holder 31 can be increased. The cutting blade 1 can be firmly bound, and thus high-efficiency machining is easy. The cutting edge length L1 is more preferably 0.55×D1 or less.
[0072] In addition, in the present embodiment, the width of the second side surface 11B in the direction orthogonal to the center line O1 becomes larger as it approaches the seating surface 3, and thus it can also adapt to the shape change of the holder 31 caused by use over time. Figure 8It is an explanatory diagram showing the change in the constrained state of the cutting blade 1 due to the change over time of the holder 31. Figure 9 It is an explanatory diagram showing the change in the constrained position.
[0073] As Figure 8 and Figure 9 shown, in the indexable insert type rotary cutting tool 30 in the new product state, the contact position of the second side surface 11B of the cutting blade 1 with the seat wall surface 35, that is, the constrained portion R1, is at a relatively high position in the thickness direction of the cutting blade 1. On the other hand, when the holder 31 is worn due to use over time, as Figure 8 shown in the right figure of, the upper end corner portion of the seat wall surface 35 has a rounded corner due to wear. If the cutting blade 1 is mounted on such a worn holder 31, the height position of the constrained portion R2 is lower than that of the constrained portion R1 and is close to the seat bottom surface 34.
[0074] As Figure 9 shown, the width of the second side surface 11B in the direction orthogonal to the center line O1 becomes larger as it approaches the seating surface 3. Therefore, the length of the constrained portion R2 after the holder is worn is larger than the length of the constrained portion R1 in the new product state. Thus, when the holder 31 deteriorates due to use over time, the binding force of the cutting blade 1 can be increased, and therefore the influence of the deterioration of the holder 31 on the machining quality can be reduced.
[0075] Figure 5 The imaginary line Lb shown is a straight line showing the extending direction of the contact portion (constrained portion) of the second side surface 11B with the seat wall surface 35 in the illustrated mounted state for convenience. The imaginary line W is a straight line passing through the tool lowest point 20L of the indexable insert type rotary cutting tool 30 and orthogonal to the rotation axis J1. In the present embodiment, the imaginary line Lb is substantially parallel to the imaginary line W. On the other hand, the main cutting edge 21 cutting into the workpiece is inclined toward the axially rear side as it goes toward the radially outer side of the holder 31 with respect to these imaginary lines Lb and W.
[0076] During cutting, a force F0 acts on the cutting blade 1 in a direction orthogonal to the main cutting edge 21. As a result, a force F1 in the direction parallel to the force F0 acts on the seat wall surface 35. Since the seat wall surface 35 intersects the force F1 at an angle less than 90°, the force F1 can be decomposed into a component vertically pressing the seat wall surface 35 and a component toward the radially inner side of the holder 31. Thus, the cutting blade 1 is pressed toward the radially inner side, that is, the seat wall surface 36, by the cutting resistance. According to the indexable insert type rotary cutting tool 30 of the present embodiment, due to the cutting resistance during cutting, the cutting blade 1 is pressed against the seat wall surfaces 35 and 36, so the cutting blade 1 is firmly constrained on the holder 31. It is possible to perform cutting while holding the cutting blade 1 in a stable posture, and thus a high-quality machined surface can be obtained.
[0077] In the present embodiment, it is preferable that the lowest point 20L of the tool is located on the finishing edge 22, and the cutting-in angle K satisfies 5° ≤ K ≤ 25°.
[0078] By disposing the lowest point 20L of the tool on the finishing edge 22, the width of the chip is widened, and the rise of the cutting temperature during cutting can be suppressed. Thereby, the cutting edge life can be improved.
[0079] By setting the cutting-in angle K to 5° or more, the biting property with respect to the workpiece is improved.
[0080] By setting the cutting-in angle K to 25° or less, excessive thickening of the chip can be suppressed, and thus good chip evacuation property can be obtained.
[0081] (Modification example)
[0082] In Figures 1 to 3 , the cutting blade 1 with a cutting-in angle K of 21° is illustrated. Figures 10 to 12 The cutting blade 100 of the modification example shown has a cutting-in angle K of 10°.
[0083] Figure 10 is a perspective view of the cutting blade 100. Figure 11 is a plan view showing the rake face structure of the cutting blade 100. Figure 12 is a side view showing the side structure of the cutting blade 100.
[0084] In Figures 10 to 12 , the parts marked with the same reference numerals as Figures 1 to 3 have functions common to the cutting blade of the above-described embodiment. Regarding these common parts, detailed descriptions may sometimes be omitted.
[0085] The cutting blade 100 includes: a rake face 2 constituting one of a pair of polygonal faces; a seating face 3 constituting the other of the pair of polygonal faces; a side face 10 connecting the rake face 2 and the seating face 3; and a mounting hole 7 for mounting on a holder. A cutting edge portion 120 is provided on the intersection ridge line between the rake face 2 and the side face 10. The cutting edge portion 120 includes an outer peripheral edge 25, an edge angle 24, a main cutting edge 21, a finishing edge 22, and an inner peripheral arc edge 26.
[0086] The main cutting edge 21 and the finishing edge 22 are provided on the intersection ridge line of the side face 10B connected to the short side of the rake face 2. The outer peripheral edge 25 is provided on the intersection ridge line of the side face 10A connected to the long side of the rake face 2. The edge angle 24 is provided between the main cutting edge 21 and the outer peripheral edge 25. The inner peripheral arc edge 26 is provided on the side of the finishing edge 22 opposite to the main cutting edge 21. The cutting edge portion 20 has a convex curved edge 23 connecting the main cutting edge 21 and the finishing edge 22.
[0087] The edge angle 24 is connected to the main cutting edge 21 and is located at the corner of the rake face 2. The edge angle 24 has a composite arc shape formed by a plurality of arcs in the Figure 11 top view shown. The edge angle 24 includes a first arc edge 24a connected to the main cutting edge 21 and an outermost peripheral arc edge 24b located at the outermost peripheral portion within the edge angle 24. The first arc edge 24a and the outermost peripheral arc edge 24b are arc-shaped cutting edges having different radii of curvature from each other. The radius of curvature of the outermost peripheral arc edge 24b is larger than the radius of curvature of the first arc edge 24a.
[0088] As Figure 11 shown, in the cutting blade 100 of the modification, the angle formed by the main cutting edge 21 corresponding to the cutting-in angle K and the finishing edge 22 is 10°. The cutting-in angle K of the cutting blade 100 is smaller than Figure 2 the cutting-in angle K (21°) of the cutting blade 1 shown. Therefore, the angular difference between the first side surface 11A connected to the main cutting edge 21 and the second side surface 11B connected to the finishing edge 22 is smaller than that in the structure of the cutting blade 1 in the previous embodiment. Thus, as Figure 12 shown, the width of the boundary region 111C separating the first side surface 11A and the second side surface 11B is narrower than the width of the boundary region 11C in the Figure 3 embodiment shown.
[0089] In addition, the angle θ4 formed by the straight line L connecting the end point P and the end point Q of the boundary region 111C and the seating surface 3 is smaller than the angle θ3 in the previous embodiment.
[0090] In the cutting blade 100 of the modification according to the above structure, the end point P of the boundary region 111C is provided at a position further away from the edge angle 24, so it is easy to form the straight main cutting edge 21 to be longer. Further, it is easier to suppress the local temperature rise of the main cutting edge 21 during cutting.
[0091] In addition, in the cutting blade 100 of the modification, the width of the second side surface 11B connected to the finishing edge 22 also becomes wider toward the seating surface 3 side. The contact area between the second side surface 11B and the mounting seat wall surface 35 when the cutting blade 100 is mounted on the holder 31 becomes larger, so the mounting posture of the cutting blade 100 is more stable.
[0092] As described above, although the embodiments of the present invention have been described, each structure and their combinations in the embodiments are an example, and within the scope not departing from the gist of the present invention, addition, omission, replacement, and other changes of the structure can be made. In addition, the present invention is not limited to the embodiments.
[0093] Industrial Applicability
[0094] It is possible to provide a cutting blade and an indexable insert type rotary cutting tool equipped with the above cutting blade, which can balance the strength of the main cutting edge and the suppression of flank wear of the finishing edge, and also has excellent restraint on the holder.
[0095] Explanation of reference numerals
[0096] 1 Cutting blade
[0097] 2 Rake face
[0098] 3 Seating surface
[0099] 7 Mounting hole
[0100] 10, 10A, 10B Side surfaces
[0101] 11A First side surface
[0102] 11B Second side surface
[0103] 11C Boundary region
[0104] 20 Cutting edge part
[0105] 20L Lowest point of the tool
[0106] 21 Main cutting edge
[0107] 22 Finishing edge
[0108] 23 Convex curve edge
[0109] 24 Edge angle
[0110] 30 Indexable insert type rotary cutting tool
[0111] 31 Holder
[0112] 33 Blade seat
[0113] J1 Axis of rotation
[0114] K Cutting-in angle
[0115] L1 Cutting edge length
[0116] O1 Center line
[0117] P, Q End points
[0118] θ1, θ2 Relief angles
[0119] θ3 Angle of the straight line L
Claims
1. A cutting blade, which is a polygonal plate shape, and the cutting blade includes: A rake face that constitutes one of a pair of polygonal faces; a seating face that constitutes the other of the pair of polygonal faces; A flank that connects the rake face and the seating face; and a mounting hole that opens on the rake face and the seating face and penetrates the cutting blade in the thickness direction, A cutting edge portion is provided on the intersection edge line between the rake face and the flank, The cutting edge portion includes a blade angle, a main cutting edge connected to the blade angle, a convex curve edge connected to the main cutting edge, and a finishing edge connected to the convex curve edge, The flank has a first flank connected to the main cutting edge, a second flank connected to the finishing edge, and a boundary region connected to the convex curve edge, In a side view of observing the flank from the front, the first flank and the second flank are separated to the left and right sides by the boundary region extending between the rake face and the seating face, The clearance angle θ1 of the main cutting edge and the clearance angle θ2 of the finishing edge satisfy the relationship of θ1 < θ2, When the end point on the rake face side of the boundary region is set as end point P and the center line of the mounting hole is set as O1, In the side view, the end point P is located at a position farther from the blade angle than the center line O1.
2. The cutting blade according to claim 1, wherein, When the end point on the seating face side of the boundary region is set as end point Q, in the side view, the end point Q is located at a position closer to the blade angle than the center line O1.
3. The cutting blade according to claim 1 or 2, wherein, The clearance angles θ1, θ2 satisfy: 8° ≤ θ1 ≤ 18°, and 12° ≤ θ2 ≤ 25°.
4. The cutting blade according to claim 1 or 2, wherein, In the side view, the angle θ3 formed by the straight line L connecting the end point P and the end point Q and the seating face satisfies: 45° ≤ θ3 ≤ 85°.
5. The cutting blade according to claim 1 or 2, wherein, In a top view of observing the rake face from the front, the main cutting edge is a straight cutting edge, When the cutting edge length of the main cutting edge is set as L1 and the inscribed circle diameter of the rake face is set as D1, it satisfies: 0.35×D1 ≤ L1 ≤ 0.60×D1.
6. A indexable insert type rotary cutting tool, including: The cutting blade according to claim 1 or 2; And A holder that can be detachably mounted with the cutting blade and rotates around a rotation axis, The holder has a blade mounting seat that contacts the flank and the seating face of the cutting blade relative to the finishing edge.
7. The indexable insert type rotary cutting tool according to claim 6, wherein, The lowest point of the tool is located on the finishing edge, The cutting-in angle K satisfies: 5° ≤ K ≤ 25°.
Citation Information
Patent Citations
Cutting insert and cutting edge replaceable cutting tool
JP2022151053A
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JP2023053255A