rotary saw

Abstract

To effectively extend the service life of a chip.SOLUTION: A rotary saw 10 comprises: a discoid blade metal 20, the outer periphery of which has a plurality of blade bases 22; and a plurality of chips 30A, 30B and 30C fixed on the plurality of blade bases 22. The plurality of chips 30A, 30B and 30C includes cutting faces 31A, 31B and 31C extending radially in the base metal 20 and flanks 34A, 34B and 34C extending circumferentially in the base metal 20, where the flank 34A comprises at least two or more surfaces 35A1, 35A2, 36A1, 36A2, 37A1 and 37A2 with relief angles different from each other.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present disclosure relates to a rotary saw (circular saw blade) used for cutting, milling, etc. of a workpiece. [Background technology]

[0002] Generally, rotary saws are constructed by arranging multiple tips at a predetermined pitch around the outer periphery of a disk-shaped base. Each tip is roughly rectangular and has a rake face extending radially of the base and a relief face extending circumferentially of the base.

[0003] An example of this type of rotary saw is disclosed in, for example, Patent Document 1. The rotary saw described in Patent Document 1 has, as a plurality of tips, a serrated cutting edge in which the flat surface portion of the flank is located at the center in the blade thickness direction when viewed from the rake face, a left cutting edge in which the flat surface portion of the flank is offset to the left of the center in the blade thickness direction when viewed from the rake face, and a right cutting edge in which the flat surface portion of the flank is offset to the right of the center in the blade thickness direction when viewed from the rake face. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2012-232409 Summary of the Invention [Problem to be solved by the invention]

[0005] In the rotary saw described in Patent Document 1, the tips are formed with different heights. Specifically, the height of the serrated edge is higher than that of the left and right blades. In this configuration, as the serrated edge wears as the workpiece is cut or milled, when the serrated edge reaches a height approximately equal to that of the left and right blades, the serrated edge becomes less likely to bite into the workpiece. As a result, even if a flat surface remains on the serrated edge, the serrated edge may no longer be able to cut or mill the workpiece. In other words, there is room for improvement in the lifespan of the serrated edge tips. This issue can occur even when multiple tips are configured with the same height, if uneven wear occurs among the tips.

[0006] The technology of the present disclosure has been made in consideration of the above circumstances, and aims to provide a rotary saw that can effectively extend the life of the tip. [Means for solving the problem]

[0007] The rotary saw (10) of the present disclosure includes: A disk-shaped base metal (20) having a plurality of cutting tool holders (22) formed on the outer periphery thereof, and a plurality of the cutting tool holders ( 22), and a plurality of chips (30A, 30B, 30C) respectively fixed to the A saw (10), The plurality of tips (30A) have rake faces (31A) extending in the radial direction of the base metal (20). ) and a flank surface (34A) extending in the circumferential direction of the base metal (20), The relief surfaces (34A) have different relief angles. Includes flat surface At least two or more sides Part (35A1, 35A2, 36A1, 36A2, 37A1, 37A2) As the above, A first surface portion (35A1, 36A1, 37A1) provided on the side of the first surface portion and a second surface portion (35A2, 36A2, 37A2) provided on the opposite side to the rake face. fruit, The first surface portion is a first flat surface portion (35A1) located at the center in the left-right direction when viewed from the rake surface. ), a first right inclined surface portion (36A1) located on the right side of the first flat surface portion, and a first left inclined surface portion (37A1) located on the left side of the first inclined surface portion (37A1); The second surface portion is a second flat surface portion provided on the opposite side of the rake face with respect to the first flat surface portion. a flat surface portion (35A2) and a second flat surface portion (35A3) located on the right side of the second flat surface portion and facing the first right inclined surface portion; a second right inclined surface portion (36A2) provided on the opposite side of the rake face, and a second right flat surface portion (36A3) A second left inclined surface is located on the left side and is provided on the opposite side of the rake face with respect to the first left inclined surface. The blade is configured to include a toothed blade having a surface portion (37A2), The clearance angle of the second flat surface portion is set to be larger than the clearance angle of the first flat surface portion. are It is characterized by:

[0008] In another aspect of the present disclosure, a rotary saw (10) includes: The plurality of chips (30A, 30B, 30C) include chips having different heights. It is composed of Among the plurality of chips (30A, 30B, 30C), a chip that is taller than the other chips The flank (34A) of the cap (30A) is First surface portion (35A1, 36A1, 37A1) The second surface portion (35A2, 36A2, 37A2) and was established Characterized by

[0011] In another aspect of the rotary saw of the present disclosure, The first flat Menu ( 35A1 ) clearance angle (θ1A) is in the range of 5° to 20°, The second flat Menu ( 35A2 The clearance angle (θ2A) of the It is characterized by: [Effects of the Invention]

[0012] According to the rotary saw of the present disclosure, the life of the tip can be effectively extended. [Brief explanation of the drawings]

[0013] [Figure 1] 1 is a schematic side view of a rotary saw according to an embodiment of the present invention, viewed from the direction of a rotation axis. [Figure 2] 2 is a schematic side view showing an enlarged portion of the rotary saw shown in FIG. 1. FIG. [Figure 3] 2 is a schematic perspective view showing an enlarged portion of the rotary saw shown in FIG. 1. FIG. [Figure 4] (A) is a front view of the first tip (view from the rake surface), (B) is a side view of the first tip, (C) is a top view of the first tip, and (D) is a cross-sectional view of (C) taken along line AA. [Figure 5] (A) is a front view of the second tip (view from the rake surface), (B) is a side view of the second tip, and (C) is a top view of the second tip. [Figure 6] (A) is a front view of the third tip (view from the rake surface), (B) is a side view of the third tip, and (C) is a top view of the third tip. [Figure 7] FIG. 10 is a schematic diagram illustrating a comparative example. [Figure 8] 5A and 5B are schematic diagrams illustrating the operation of the present embodiment. [Figure 9] FIG. 10 is a schematic perspective view showing an enlarged portion of a rotary saw according to a modified example. [Figure 10] FIG. 10 is a schematic perspective view showing an enlarged portion of a rotary saw according to a modified example. DETAILED DESCRIPTION OF THE INVENTION

[0014] Hereinafter, a rotary saw according to this embodiment will be described with reference to the accompanying drawings.

[0015] [Overall configuration] 1 is a schematic side view of a rotary saw 10 according to this embodiment, viewed from the direction of the rotation axis. The rotary saw 10 is attached to a rotation support shaft of a power tool, cutting machine, or the like (not shown). The rotary saw 10 cuts and / or mills a workpiece (e.g., a metal material) by rotating, for example, counterclockwise (left-handed) in FIG. 1.

[0016] In the following description, the direction in which the rotary saw 10 rotates when cutting or milling a workpiece is referred to as the "forward rotation direction," and the direction opposite to the forward rotation direction is referred to as the "reverse rotation direction." The forward rotation direction side is referred to as the "front side," and the reverse rotation direction side is referred to as the "rear side." The direction of the rotation axis of the rotary saw 10 is referred to as the "left-right direction, width direction, and blade thickness direction." The front side of the paper in Figure 1 is referred to as the right side, and the back side of the paper is referred to as the left side.

[0017] The rotary saw 10 includes a base metal 20 and a plurality of tips 30 (30A, 30B, 30C). The base metal 20 is a substantially circular steel plate. The material for forming the base metal 20 is not particularly limited, but carbon steel or alloy tool steel such as SK85, SKS5, SAE1074, or DIN75Cr1 can be used, for example. A circular shaft hole 23 is formed in the rotation center of the base metal 20, for assembling and fixing the rotary saw 10 to the rotation shaft of a power tool, cutting machine, or the like. The axis of the shaft hole 23 is coaxial with the rotation axis A1 of the rotary saw 10.

[0018] The dashed-dotted line LR in Figure 1 represents the radius of the rotary saw 10. The radius is the radius of an imaginary peripheral circle CR connecting the outermost protruding points of each tip 30 (in this embodiment, the first tip 30A, which is taller than the other tips 30B, 30C). The radius of the rotary saw 10 is, for example, approximately 205 mm. The radius of the rotary saw 10 is not particularly limited and can be set to an appropriate value depending on the type of workpiece, etc.

[0019] FIG. 2 is a schematic diagram showing an enlarged portion of the rotary saw 10 shown in FIG. 1. As shown in FIG. 2, a plurality of tooth chambers 21 are provided at a predetermined pitch in the circumferential direction on the outer peripheral portion of the base metal 20. The tooth chambers 21 are formed by cutting out a substantially U-shaped notch radially inward from the outer peripheral portion of the base metal 20 in a side view. The portion of the tooth chamber 21 that is recessed most radially inward is the tooth bottom 21A. A cutting edge 22 is formed between a pair of tooth chambers 21 that are adjacent to each other in the circumferential direction. In other words, a plurality of cutting edges 22 are provided at a predetermined pitch in the circumferential direction on the outer peripheral side of the base metal 20.

[0020] The plurality of blade holders 22 are provided with tip fixing portions 24 formed by cutting out the front end portion of the blade holder 22 in a generally L-shape when viewed from the side. The tip fixing portion 24 includes a front surface portion 24A extending in the radial direction of the base metal 20 and an outer surface portion 24B facing the radially outer side of the base metal 20. Each tip 30 is fixed to the plurality of tip fixing portions 24 by, for example, brazing. Specifically, the back surface of the tip 30 is fixed to the front surface portion 24A of the tip fixing portion 24, and the bottom surface of the tip 30 is fixed to the outer surface portion 24B of the tip fixing portion 24.

[0021] The outer peripheral portion 25 of the blade base 22 extends from the tip fixing portion 24 rearward at an inward angle in the radial direction, and then extends at an outward angle in the radial direction toward the rear end. That is, the rear end of the blade base 22 protrudes radially outward in a side view. Hereinafter, this outward protruding portion will be referred to as the "limiting blade LS." The limiting blade LS functions to stabilize the straightness of the rotary saw 10 while preventing the rotary saw 10 from cutting excessively into the workpiece.

[0022] The plurality of blade rests 22 each include a first blade rest 22A, a second blade rest 22B, and a third blade rest 22C. The plurality of tips 30 each include a first tip 30A, a second tip 30B, and a third tip 30C. The first tip 30A is fixed to the first blade rest 22A. The second tip 30B is fixed to the second blade rest 22B. The third tip 30C is fixed to the third blade rest 22C.

[0023] Each tip 30 is, for example, a cermet tip. Cermet tips are tips whose main components are titanium and tantalum, and are formed by bonding titanium compounds such as titanium carbide (TiC) and titanium carbonitride (TiCN) with nickel (Ni) or cobalt (Co). Note that the tips 30 are not limited to cermet tips and may be made of cemented carbide or the like.

[0024] The tips 30 are arranged on the blade holders 22A, 22B, and 22C in the order of first tip 30A, second tip 30B, and third tip 30C in the forward rotation direction. That is, when the rotary saw 10 cuts a workpiece, the tips 30 repeatedly contact the workpiece in the order of first tip 30A, second tip 30B, and third tip 30C, thereby cutting or trimming the workpiece. In this embodiment, the rotary saw 10 has, for example, 48 teeth. That is, if the first tip 30A, second tip 30B, and third tip 30C are defined as one tip group, the rotary saw 10 has 16 tip groups. The number of teeth is not limited to 48 and can be any number appropriate for the type of workpiece, etc.

[0025] Each tip 30A, 30B, 30C has a rake face 31A, 31B, 31C that extends radially of the base metal 20 and forms the front surface of the tip 30A, 30B, 30C. Hereinafter, the end portions located most outward of the rake faces 31A, 31B, 31C will be referred to as "outer peripheral end portions 40A, 40B, 40C."

[0026] The reference surface Lr1 of the first tip 30A passes through the rotation axis A1 (see FIG. 1) and the outer peripheral end 40A of the first tip 30A. The reference surface Lr2 of the second tip 30B passes through the rotation axis A1 (see FIG. 1) and the outer peripheral end 40B of the second tip 30B. The reference surface Lr3 of the third tip 30C passes through the rotation axis A1 (see FIG. 1) and the outer peripheral end 40C of the third tip 30C.

[0027] In this embodiment, the radial height H2 of the outer peripheral end 40B of the second tip 30B and the radial height H3 of the outer peripheral end 40C of the third tip 30C are approximately equal to each other (H2 = H3). The radial height H1 of the outer peripheral end 40A of the first tip 30A is higher than the radial heights H2 and H3 of the second tip 30B and the third tip 30C (H1 > H2 = H3). The radial height H0 of the limiting blade LS is lower than the radial height H1 of the first tip 30A, the radial height H2 of the second tip 30B, and the radial height H3 of the third tip 30C (H1 > H2 = H3 > H0). The heights H0, H1, H2, and H3 are radial lengths based on the outer periphery O1 of a circle centered on the rotation axis A1 and passing through the tooth bottom 21A.

[0028] [Chips 30A, 30B, 30C] Next, the specific shapes of the first tip 30A, the second tip 30B, and the third tip 30C will be described in detail.

[0029] Fig. 3 is a schematic perspective view of each of the chips 30A, 30B, and 30C. Fig. 4 is a diagram illustrating details of the first chip 30A. Fig. 5 is a diagram illustrating details of the second chip 30B. Fig. 6 is a diagram illustrating details of the third chip 30C.

[0030] [Second chip 30B] First, the second tip 30B will be described in detail with reference to Figures 3 and 5. The second tip 30B is substantially rectangular parallelepiped-shaped and has a rake face (front surface) 31B, a flank surface 34B, a right side surface 38B, and a left side surface 39B.

[0031] The rake face 31B includes a first rake face 32B on the radially inner side and a second rake face 33B on the radially outer side. The radially outer end of the second rake face 33B is connected to the front end of the flank face 34B. The second rake face 33B is inclined at a predetermined angle relative to the first rake face 32B. The angle θ3B (see FIG. 5(B)) formed between the first rake face 32B and the second rake face 33B is not particularly limited, but in this embodiment, it is, for example, approximately 10°.

[0032] The flank 34B includes a flat surface 35B that is substantially parallel to the thickness direction of the base metal 20, and a right inclined surface 36B. The right inclined surface 36B is a surface formed so as to be continuous with the right end portion of the flat surface 35B. The right inclined surface 36B is a surface formed by chamfering a right intersection portion, which is an intersection portion between the upper surface (the same imaginary plane as the flat surface 35B) and the right surface 38B. In other words, the second tip 30B is a so-called "left-hand cutting edge" in which the flat surface 35B of the flank 34B is offset to the left in the thickness direction of the base metal 20. The inclination angle θ4B of the right inclined surface 36B with respect to the flat surface 35B (see FIG. 5(A)) is not particularly limited, but in this embodiment, it is, for example, approximately 30°. Further, the tip clearance angle θ1B (see FIG. 5B), which is the angle formed between the flat surface 35B and a line D2 perpendicular to the reference surface Lr2, is not particularly limited, but is, for example, about 13° in this embodiment.

[0033] [Third chip 30C] Next, the third tip 30C will be described in detail with reference to Figures 3 and 6. The third tip 30C is substantially rectangular parallelepiped-shaped and has a rake face (front surface) 31C, a flank surface 34C, a right side surface 38C, and a left side surface 39C.

[0034] The rake face 31C includes a first rake face 32C on the radially inner side and a second rake face 33C on the radially outer side. The radially outer end of the second rake face 33C is connected to the front end of the flank face 34C. The second rake face 33C is inclined at a predetermined angle relative to the first rake face 32C. The angle θ3C (see FIG. 6(B)) formed between the first rake face 32C and the second rake face 33C is not particularly limited, but in this embodiment, it is, for example, approximately 10°.

[0035] The flank 34C includes a flat surface 35C that is substantially parallel to the thickness direction of the base metal 20, and a left inclined surface 37C. The left inclined surface 37C is a surface formed so as to be continuous with the left end of the flat surface 35C. The left inclined surface 37C is a surface formed by chamfering a left intersection, which is an intersection between the upper surface (the same imaginary plane as the flat surface 35C) and the left side surface 39C. In other words, the third tip 30C is a so-called "right-hand cutting edge" in which the flat surface 35C of the flank 34C is offset to the right in the thickness direction of the base metal 20. The inclination angle θ5C of the left inclined surface 37C with respect to the flat surface 35C (see FIG. 6(A)) is not particularly limited, but in this embodiment, it is, for example, approximately 30°. Further, the tip clearance angle θ1C (see FIG. 6B), which is the angle formed between the flat surface 35C and a line D3 perpendicular to the reference surface Lr3, is not particularly limited, but is, for example, about 13° in this embodiment.

[0036] [First chip 30A] Next, the first tip 30A will be described in detail with reference to Figures 3 and 4. The first tip 30A is substantially rectangular parallelepiped-shaped and has a rake face (front surface) 31A, a flank surface 34A, a right side surface 38A, and a left side surface 39A.

[0037] The rake face 31A includes a first rake face 32A on the radially inner side and a second rake face 33A on the radially outer side. The radially outer end of the second rake face 33A is connected to the front end of the flank face 34A. The second rake face 33A is inclined at a predetermined angle with respect to the first rake face 32A. The angle θ3A (see FIG. 4(B)) formed between the first rake face 32A and the second rake face 33A is not particularly limited, but in this embodiment, it is, for example, approximately 10°.

[0038] The relief surface 34A includes a flat surface 35A that is substantially parallel to the thickness direction of the base metal 20, a right inclined surface 36A, and a left inclined surface 37A. The right inclined surface 36A is a surface formed so as to be continuous with the right end portion of the flat surface 35A. The right inclined surface 36A is a surface formed by chamfering a right intersection portion, which is an intersection portion between the top surface (the same imaginary plane as the flat surface 35A) and a right side surface 38A. The left inclined surface 37A is a surface formed so as to be continuous with the left end portion of the flat surface 35A. The left inclined surface 37A is a surface formed by chamfering a left intersection portion, which is an intersection portion between the top surface (the same imaginary plane as the flat surface 35A) and a left side surface 39A. That is, the first tip 30A is a so-called "ridged cutting edge" in which a flat surface 35A of the flank 34A is located at the center in the thickness direction of the base metal 20, a right inclined surface 36A of the flank 34A is located to the right of the flat surface 35A, and a left inclined surface 37A of the flank 34A is located to the left of the flat surface 35A. A tip clearance angle θ1A (see FIG. 4(B)), which is the angle formed between a line D1 perpendicular to the reference plane Lr1 and the flat surface 35A, is not particularly limited, but is, for example, about 13° in this embodiment.

[0039] Here, a comparative example will be described with reference to Fig. 7, in which the flat surface 350A of the first tip 300A is formed as a single plane from the front end to the rear end. In the comparative example shown in Fig. 7, the first tip 300A is, for example, a crested cutting edge, the second tip 300B is, for example, a left cutting edge, and the third tip 300C is, for example, a right cutting edge. The height of the first tip 300A is formed to be greater than the heights of the second tip 300B and the third tip 300C.

[0040] In the configuration shown in FIG. 7 , as the first tip 300A, second tip 300B, and third tip 300C wear as the workpiece is cut or milled, the first tip 300A wears faster than the second tip 300B and the third tip 300C. As a result, the height of the first tip 300A becomes approximately equal to the heights of the second tip 300B and the third tip 300C, as indicated by the dashed-dotted lines in FIG. 7 . At this time, an unworn portion X remains on the rear end of the flat surface 350A of the first tip 300A. However, because the height of the first tip 300A becomes equal to the heights of the second tip 300B and the third tip 300C and the clearance angle of the unworn portion X becomes very small, the first tip 300A has difficulty penetrating the workpiece, and the unworn portion X is no longer able to cut or mill the workpiece. That is, even if the non-wear portion X remains on the flat surface 350A of the first tip 300A, the workpiece cannot be cut or milled, and it can be said that there is room for improvement in the life of the first tip 300A.

[0041] Therefore, in this embodiment, as shown in Figures 3 and 4, the flat surface 35A, right inclined surface 36A, and left inclined surface 37A of the clearance surface 34A of the first tip 30A are made into two-stage inclined surfaces with different clearance angles on the front end side and the rear end side.

[0042] Specifically, the flat surface 35A has a first flat surface portion 35A1 on the rake face side (front end side) and a second flat surface portion 35A2 on the opposite side of the rake face (rear end side) from the first flat surface 35A1. The right inclined surface 36A has a first right inclined surface portion 36A1 on the rake face side (front end side) and a second right inclined surface portion 36A2 on the opposite side of the rake face (rear end side) from the first right inclined surface portion 36A1. The left inclined surface 37A has a first left inclined surface portion 37A1 on the rake face side (front end side) and a second left inclined surface portion 37A2 on the opposite side of the rake face (rear end side) from the first left inclined surface portion 37A1. The inclination angle θ4A1 (see FIG. 4A) of the first right inclined surface portion 36A1 relative to the first flat surface portion 35A1 and the inclination angle θ5A1 (see FIG. 4A) of the first left inclined surface portion 37A1 relative to the first flat surface 35A1 are not particularly limited, but are, for example, about 45° in this embodiment. The inclination angle θ4A2 (see FIG. 4D) of the second right inclined surface portion 36A2 relative to the second flat surface portion 35A2 and the inclination angle θ5A2 (see FIG. 4D) of the second left inclined surface portion 37A2 relative to the second flat surface 35A2 are not particularly limited, but are, for example, about 45° in this embodiment.

[0043] In this embodiment, the ratio of the circumferential lengths of the first flat surface portion 35A1 to the second flat surface portion 35A2, the ratio of the circumferential lengths of the first right inclined surface portion 36A1 to the second right inclined surface portion 36A2, and the ratio of the circumferential lengths of the first left inclined surface portion 37A1 to the second left inclined surface portion 37A2 is, for example, 1:1. These ratios of the circumferential lengths are not particularly limited and can be appropriately set depending on the heights H1, H2, and H3 and pitch of the inserts 30A, 30B, and 30C, the type of workpiece, and the like. Hereinafter, the portion where the first flat surface portion 35A1 and the second flat surface portion 35A2 intersect will be referred to as the "flat surface top."

[0044] As shown in FIG. 4, the clearance angle of the first flat surface portion 35A1 is the aforementioned leading edge clearance angle θ1A, which is the angle between the first flat surface portion 35A1 and a line D1 perpendicular to the reference plane Lr1. In this embodiment, the clearance angle θ1A of the first flat surface portion 35A1 is, for example, approximately 13°. Hereinafter, the clearance angle θ1A of the first flat surface portion 35A1 will be referred to as the "first flat surface clearance angle." Note that the first flat surface clearance angle θ1A is not limited to approximately 13° and can be an appropriate angle (e.g., 5° to 20°) depending on the heights H1, H2, and H3 of the inserts 30A, 30B, and 30C, the pitch, the type of workpiece, and the like. Although detailed explanations using drawings will be omitted, the clearance angle of the first right inclined surface portion 36A1 will be referred to as the "first right inclined surface clearance angle," and the clearance angle of the first left inclined surface portion 37A1 will be referred to as the "first left inclined surface clearance angle."

[0045] The clearance angle θ2A of the second flat surface portion 35A2 is the angle formed by the second flat surface portion 35A2 and a line D4 that is perpendicular to the rotation axis A1 (see FIG. 1) and a reference plane Lr4 (see FIG. 4B) that passes through the top of the flat surface 35A. Hereinafter, the clearance angle θ2A of the second flat surface portion 35A2 will be referred to as the "second flat surface clearance angle." The second flat surface clearance angle θ2A is set to be larger than the first flat surface clearance angle θ1A (θ2A > θ1A). In other words, the second flat surface portion 35A2 is configured to be more inclined with respect to the reference plane Lr4 than the first flat surface portion 35A1. In this embodiment, the second clearance angle θ2A is, for example, approximately 20°. The second clearance angle θ2A is not limited to approximately 20°, but can be set to an appropriate angle within a range (e.g., 10° to 45°) that is at least larger than the first clearance angle θ1A and smaller than 90°, depending on the heights H1, H2, and H3 of the inserts 30A, 30B, and 30C, the pitch, the type of workpiece, and the like. Although detailed explanations using drawings are omitted, the clearance angle of the second right slope portion 36A2 will be referred to as the "second right slope clearance angle," and the clearance angle of the second left slope portion 37A2 will be referred to as the "second left slope clearance angle." The second right slope clearance angle is set to an angle larger than the first right slope clearance angle. The second left slope clearance angle is set to an angle larger than the first left slope clearance angle.

[0046] The effects of the first tip 30A according to this embodiment configured as described above will be described with reference to FIG. 8. As shown by the dashed lines in FIG. 8, as the first tip 30A, the second tip 30B, and the third tip 30C wear out during cutting or milling of the workpiece, the first tip 30A wears out faster than the second tip 30B and the third tip 30C. Assume that the wear of the first tip 30A, the second tip 30B, and the third tip 30C has progressed to the levels indicated by the dashed lines in FIG. 8. At this time, the second flat surface portion 35A2, the second right inclined surface portion 36A2, and the second left inclined surface portion 37A2 remain on the flank 34A of the first tip 30A. The second flat surface portion 35A2 is formed with a larger clearance angle than the first flat surface portion 35A1, the second right inclined surface portion 36A2 is formed with a larger clearance angle than the first right inclined surface portion 36A1, and the second left inclined surface portion 37A2 is formed with a larger clearance angle than the first left inclined surface portion 37A1. In other words, when the second flat surface portion 35A2, the second right inclined surface portion 36A2, and the second left inclined surface portion 37A2 abut against the workpiece, the clearance angles can be more reliably secured than in the comparative example shown in FIG.

[0047] As a result, when the wear of each tip 30A, 30B, 30C progresses to the level indicated by the dashed line in FIG. 8 , the height of the second tip 30B (left cutting edge) and the third tip 30C (right cutting edge) becomes higher than the first tip 30A (ridged cutting edge), making it easier for the second tip 30B and the third tip 30C to bite into the workpiece. That is, when the second flat surface portion 35A2, the second right inclined surface portion 36A2, and the second left inclined surface portion 37A2 of the first tip 30A begin to contact the workpiece, the second tip 30B and the third tip 30C can easily bite into the workpiece. This allows the second tip 30B and the third tip 30C to function primarily and the first tip 30A to function secondary to effectively cut or mill the workpiece. As a result, the life of the first tip 30A can be effectively improved, and the product life of the rotary saw 10 can be reliably extended.

[0048] [others] The present disclosure is not limited to the above-described embodiments, and various modifications are possible without departing from the scope of the present disclosure.

[0049] For example, it has been described that the flat surface 35A has two surfaces, a first flat surface portion 35A1 and a second flat surface portion 35A2, the right inclined surface portion 36A has two surfaces, a first right inclined surface portion 36A1 and a second right inclined surface portion 36A2, and the left inclined surface portion 37A has two surfaces, a first left inclined surface portion 37A1 and a second left inclined surface portion 37A2, but it is also possible to provide three or more surfaces each with different clearance angles.

[0050] 9, all of the tips 30 may be serrated. In this case, all of the serrated edges may be first tips 30A in which the flat surface 35A has a first flat surface portion 35A1 and a second flat surface portion 35A2, the right slope portion 36A has a first right slope portion 36A1 and a second right slope portion 36A2, and the left slope portion 37A has a first left slope portion 37A1 and a second left slope portion 37A2, or only the serrated edge that is higher than the other serrated edges may be the first tip 30A.

[0051] Furthermore, as shown in FIG. 10, it is possible to configure not only the first tip 30A, which is a crenellated cutting edge, but also the second tip 30B, which is a left cutting edge, by providing a first flat surface portion 35B1 and a second flat surface portion 35B2 on the flat surface 35B, and a first right inclined surface portion 36B1 and a second right inclined surface portion 36B2 on the right inclined surface portion 36B, and the third tip 30C, which is a right cutting edge, by providing a first flat surface portion 35C1 and a second flat surface portion 35C2 on the flat surface 35C, and a first left inclined surface portion 37C1 and a second left inclined surface portion 37C2 on the left inclined surface portion 37C. [Explanation of symbols]

[0052] 10... rotary saw, 20... base metal, 21... tooth chamber, 21A tooth bottom, 22A... first blade rest, 22B... second blade rest, 22C... third blade rest, 23... shaft hole, 24... tip fixing portion, 25... outer periphery, LS... limiting blade, 30A... first tip, 30B... second tip, 30C... third tip, 31A to 31C... rake face, 32A to 32C... first rake face, 33A to 33C... second rake face, 34A to 34C ...flank surface, 35A~35C...flat surface, 35A1...first flat surface part, 35A2...second flat surface part, 36A, 36B...right slope, 36A1...first right slope part, 36A2...second right slope part, 37A, 37C...left slope, 37A1...first left slope, 37A2...second left slope, 38A~38C...right side, 39A~39C...left side, θ1A...first flat surface relief angle, θ2A...second flat surface relief angle

Claims

1. A disk-shaped base metal having a plurality of cutting blades formed on the outer periphery thereof, and a plurality of cutting blades fixed to the cutting blades. and a plurality of tips, The plurality of chips have a rake face extending in the radial direction of the base metal and a rake face extending in the circumferential direction of the base metal. and a flank surface, The flank includes at least two or more flat surface portions each having a different clearance angle, a first surface portion provided on the rake face side, and a second surface portion provided on the opposite side of the rake face with respect to the first surface portion; and a second surface portion provided on the The first surface portion includes a first flat surface portion located at the center in the left-right direction when viewed from the rake surface, and a first right inclined surface portion located on the right side of the first flat surface portion; and a first left inclined surface portion located on the left side of the first flat surface portion. a beveled portion; The second surface portion is a second flat surface portion provided on the opposite side of the rake face with respect to the first flat surface portion. a flat surface portion, and a rake surface located on the right side of the second flat surface portion and facing the first right inclined surface portion; a second right inclined surface portion provided on the opposite side to the second flat surface portion, and a first left inclined surface portion provided on the left side of the second flat surface portion and a second left inclined surface portion provided on the opposite side of the rake face with respect to the inclined surface portion. It is composed of The clearance angle of the second flat surface portion is set to be larger than the clearance angle of the first flat surface portion. are A rotary saw characterized by:

2. 2. The rotary saw of claim 1, The plurality of chips include chips having different heights, The first surface portion is provided on the flank surface of a tip that is higher than the other tips among the plurality of tips. and the second surface portion A rotary saw characterized by:

3. 3. The rotary saw according to claim 1 or 2, The clearance angle of the first flat surface portion is in the range of 5° to 20°; The clearance angle of the second flat surface portion is in the range of 10° to 45°. A rotary saw characterized by:

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