Tip of circular saw for cutting metal and manufacturing method thereof

Abstract

To provide a tip in a circular saw for cutting metal, having excellent durability and defect resistance and capable of providing a high cutting performance.SOLUTION: The entire of a tip has a substantially vertically-long rectangular parallelepiped shape. The entire of a top surface 7 has a mountain shape. In a center portion of a top surface front edge 7a, a first flank 8 having a triangular downward inclined shape extending rearward with the center portion as a bottom side is formed. A peak 9b facing a peak 8b of the first flank 8 is provided in a rear part of the first flank 8. A second flank 9 having an inverted-triangular downward inclined shape with a rear edge 7b of the top surface 7 as a bottom side is formed. The second flank 9 has downward inclination larger than that of the first flank 8. In both right and left sides of the first flank 8 and the second flank 9, a third flank 11 and a fourth flank 12 having downward inclined shape of descending in both right-side and left-side directions are formed.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to tips that are fixed to saw blade seats provided at predetermined intervals on the outer periphery of the base metal of a circular saw for cutting metal, and to a method for manufacturing the same. [Background technology]

[0002] A metal-cutting circular saw has saw blades formed at a predetermined interval on the outer periphery of a disk-shaped base metal, and tips fixed to bases attached to the saw blades. Such metal-cutting circular saws are primarily used to cut hard workpieces such as steel pipes. During the cutting process, the tips must be strong enough to prevent chipping during rotational contact with the workpiece, while also minimizing contact resistance during rotational contact with the workpiece to enhance cutting performance. However, while sharpness is generally required for the tips to minimize contact resistance, increasing sharpness can lead to the problem of increased tip chipping.

[0003] In a conventional metal-cutting circular saw in which saw blades are formed at regular intervals on the outer periphery of a disk-shaped base metal and tips are fixed to seats provided on the saw blades, there is known a type in which the flank of the tip has a first flank located in the center where the flank and rake face meet via a cutting edge ridge where the flank and rake face intersect, second and third flanks located at an angle to both sides from the first flank, and a fourth flank rearward of the first flank having a clearance angle larger than that of the first flank, the fourth flank intersecting with the first flank via its apex ridge and presenting a trapezoidal shape with the ridge with the first flank as its apex edge, the ridge on the back side of the tip as its base, and intersecting with the second and third flanks via left and right ridges. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2017-42842 A Summary of the Invention [Problem to be solved by the invention]

[0005] The flank of the insert in the above-mentioned metal-cutting circular saw is configured with a total of four surfaces: a square first flank located in the center of the cutting edge with the rake face; a trapezoidal fourth flank located behind the first flank; and second and third flanks located on both sides of the fourth flank and the first flank. However, since the first flank, which comes into closest contact with hard workpieces such as steel pipes, is square and the fourth flank is trapezoidal, the insert is able to achieve a certain degree of durability and chipping resistance, but is not sharp along the entire length of the flank from the leading edge to the trailing edge, and therefore is insufficient in terms of cutting performance.

[0006] An object of the present invention is to provide a tip for a metal-cutting circular saw or the like that is excellent in durability and chipping resistance and also provides high cutting performance. [Means for solving the problem]

[0007] The present invention described in claim 1 is a metal-cutting circular saw tip having a generally vertically elongated rectangular parallelepiped shape overall, the entire top surface being mountain-shaped, a first flank surface that has a downwardly sloping triangle shape and extends rearward from the center of the front edge of the top surface, with that part as its base, and a second flank surface that has a downwardly sloping inverted triangle shape and has a base at the rear edge of the top surface and an apex opposite the apex of the first flank surface, the second flank surface having a downward slope greater than that of the first flank surface, and third and fourth flank surfaces that slope downwardly to the left and right are formed on both the left and right sides of the first and second flank surfaces.

[0008] The present invention according to claim 2 is characterized in that in the insert according to claim 1, the apex of the first flank face and the apex of the second flank face are in contact with each other.

[0009] The present invention as set forth in claim 3 relates to the insert as set forth in claim 1 or claim 2, wherein the side flanks are inclined at a predetermined radial angle and at a predetermined tangential angle.

[0010] The present invention as set forth in claim 4 is directed to the tip of the metal-cutting circular saw as set forth in claim 3, in which a cutting face having a negative inclination angle is formed on the upper front surface, and chamfered portions are provided on both the left and right sides of the cutting face.

[0011] The present invention of claim 5 is characterized in that, for the insert for a metal-cutting circular saw according to claim 1 or claim 2, the inclination angle of the first flank is within a range of 1° to 15°, the inclination angle of the second flank is within a range of 2° to 35°, and the inclination angle of the second flank is greater than the inclination angle of the first flank. That is, in the insert having the configuration according to claim 1 or claim 2, the inclination angle of the first flank is set within a range of 1° to 15° because, if the inclination angle of the first flank exceeds 15°, there is a significant tendency for the second flank to be unable to be formed sufficiently. Therefore, it is preferable that the inclination angle of the first flank be set within a range of 1° to 15°. Furthermore, the inclination angle of the second flank is set within a range of 2° to 35° because, in order to set the inclination angle of the second flank to a larger angle than that of the first flank, a minimum inclination of 2° is required. However, if the inclination angle exceeds 35°, cutting performance due to the second flank significantly decreases. Therefore, it is preferable that the upper limit of the inclination angle be 35°.

[0012] The present invention as set forth in claim 6 is characterized in that, for the tip of the metal-cutting circular saw as set forth in claim 1 or claim 2, the length of the first flank is 50% or less of the front-to-back length of the top face of the tip. That is, since the first flank contacts the workpiece before the second flank, if the length of the first flank exceeds 50% of the front-to-back length of the top face of the tip, there is a significant tendency for the cutting performance of the second flank following the first flank to decrease, and therefore it is preferable to ensure a sufficient front-to-back length of the second flank by setting the length of the first flank to 50% or less of the front-to-back length of the top face of the tip.

[0013] The present invention as set forth in claim 7 is a method for manufacturing a tip for a metal-cutting circular saw as set forth in claim 1 or claim 2, comprising: a mountain-shaped portion forming step of forming left and right inclined surfaces that descend in both left and right directions with a center line extending from the center of the leading edge to the center of the trailing edge of the top surface of a vertically elongated rectangular solid-shaped tip raw material as a ridgeline, thereby making the entire top surface into a mountain-shaped portion; a first flank surface forming step of forming a triangular first flank surface with the center of the leading edge as a base by partially cutting an upper part of the mountain-shaped portion along the ridgeline and sloping downward by a predetermined length from the leading edge toward the rear, thereby forming a triangular first flank surface with the center of the leading edge as a base; and a second flank surface forming step of forming an inverted triangular second flank surface rearward of the first triangular flank surface by cutting an upper part of the mountain-shaped portion from the apex or near the apex of the triangular first flank surface to the rear edge at a downward slope that is greater than that of the first flank surface, wherein a third flank surface and a fourth flank surface are formed on the left and right sides of the second flank and first flank surfaces by the second flank surface forming step.

[0014] The present invention of claim 8 is characterized in that, in the chip manufacturing method of claim 7, in the mountain-shaped portion forming process, the ridge line of the mountain-shaped portion is formed in a downward slope from the leading edge side to the trailing edge side.

[0015] The present invention as set forth in claim 9 is characterized in that the chip manufacturing method as set forth in claim 7 or claim 8 further includes a bevel forming step, prior to the mountain-shaped portion forming step, of forming a predetermined radial angle and a predetermined tangential angle on the side relief surface portion of the chip raw material.

[0016] The present invention as set forth in claim 10 is characterized in that the tip manufacturing method as set forth in claim 9 further includes, between the mountain-shaped portion forming step and the first flank face forming step, a rake face forming step for forming a rake face having a negative inclination angle on the upper front surface of the tip raw material, and a bevel processing step for forming chamfered portions on both the left and right sides of the rake face formed by the rake face forming step.

[0017] The present invention described in claim 11 is a metal-cutting circular saw having saw blades arranged at a predetermined interval around the outer periphery of a base metal and tips fixed to the base of the saw blades, in which the tips fixed are the tips described in claim 1 or claim 2. [Effects of the Invention]

[0018] The insert according to the present invention has a generally elongated rectangular parallelepiped shape, the entire top surface of which is mountain-shaped, and a downwardly sloping first flank surface of a triangle is formed in the central portion of the front edge of the top surface, extending rearward from that portion as its base, and a downwardly sloping second flank surface of an inverted triangle is formed behind the first flank surface, having an apex opposite the apex of the first flank surface and having the rear edge of the top surface as its base, the second flank surface having a downward slope greater than that of the first flank surface, and on both the left and right sides of the first and second flank surfaces are formed a downwardly sloping third flank surface and a fourth flank surface which slope downward to the left and right.Therefore, when cutting a hard workpiece such as a steel pipe, the base of the downwardly sloping triangular first flank surface first comes into contact with the workpiece, ensuring a sufficient cutting width, and the contact area with the workpiece gradually decreases toward the apex of the rear portion of the first flank surface, thereby reducing contact resistance during cutting. Then, at the top surface of the chip, the triangular first flank and then the inverted triangular second flank come into contact with the workpiece, and at this time, the apex portion of the second flank comes into contact first, following the apex of the triangular first flank, so that the second flank comes into contact with a small contact area, continuing the cutting by the first flank, and so the initial cutting resistance is kept low, and then cutting is performed so that the contact area gradually widens towards the rear base portion of the inverted triangular second flank, ensuring cutting with a sufficient contact width without generating large contact resistance.

[0019] In summary, with the tip of the present invention, the cooperation between the triangular first flank and the inverted triangular second flank provides the exceptional effect of reducing contact resistance with the workpiece and enabling cutting with a sufficient cutting width. [Brief explanation of the drawings]

[0020] [Figure 1] 1 is a perspective view of a saw blade portion of a metal-cutting circular saw according to an embodiment of the present invention. FIG. [Figure 2] FIG. 2 is a plan view of a saw blade portion of the metal-cutting circular saw of FIG. 1. [Figure 3] FIG. 2 is a side view of the saw blade portion of the metal-cutting circular saw of FIG. [Figure 4] 2 is a perspective view of the metal-cutting circular saw of FIG. 1, in which chip-splitting grooves are formed on the tip flank surface. FIG. [Figure 5] FIG. 1 is a perspective view of a chip raw material. [Figure 6] This is an oblique view of the chip raw material with radial and tangential angles applied to the side flank surface. [Figure 7] FIG. 10 is a perspective view of a chip raw material with a mountain-shaped portion formed on the top surface thereof. [Figure 8] FIG. 10 is a perspective view of a chip raw material with a rake face formed on the upper front surface thereof. [Figure 9] FIG. 10 is a perspective view showing a state in which chamfered portions are formed on both the left and right sides of the rake face. [Figure 10] FIG. 10 is a perspective view showing a state in which a first flank is formed on a peak portion on the top surface of a chip raw material. [Figure 11] FIG. 11 is a perspective view showing a state in which a second flank and third and fourth flanks are formed behind the first flank in FIG. [Figure 12] FIG. 10 is a perspective view showing a state in which a chip-splitting groove is formed on a third flank. [Figure 13] FIG. 10 is a perspective view of a saw blade portion of a metal-cutting circular saw showing another embodiment of a flank on the tip top surface. [Figure 14] FIG. 14 is a side view of the metal-cutting circular saw of FIG. 13. [Figure 15] FIG. 1 is a perspective view of a saw blade portion of a metal-cutting circular saw used in a comparative performance test. DETAILED DESCRIPTION OF THE INVENTION

[0021] Next, an embodiment of the present invention will be described with reference to the drawings, but the present invention is not limited to such an embodiment.

[0022] In the present invention, "front and rear," "left and right," and "up and down" refer to Figure 3, with "front" referring to the direction of rotation of the circular saw 1 indicated by arrow A, i.e., the right side in Figure 3, and "rear" referring to the opposite side of the direction of rotation of the circular saw 1 indicated by arrow A, i.e., the left side in Figure 3. Also, "up" refers to the upper side in Figure 3, and "down" refers to the lower side in Figure 3. Furthermore, "left" refers to the back side of the drawing sheet in Figure 3, and "right" refers to the front side of the drawing sheet in Figure 3.

[0023] As shown in Figures 1 to 3, the basic configuration of the metal-cutting circular saw 1 according to this embodiment will be explained. The metal-cutting circular saw 1 is configured such that a tip 5, which will be described later, is fixed to a base 4 of a saw blade 3 formed at a predetermined interval on the outer periphery of a circular metal base 2 by brazing or the like.

[0024] The tip 5 has a generally elongated rectangular parallelepiped shape, a rake face 6 having a negative rake angle β formed at the upper part of the front surface 22, a top surface 7 having a mountain shape, a first flank face 8 having a downwardly sloping triangle extending rearward from a base 8a at the central portion of a leading edge 7a of the top surface 7 where the tip 5 intersects with the rake face 6, and a second flank face 9 having a downwardly sloping inverted triangle shape and a base 9a at the rear edge 7b of the top surface 7, the second flank face 9 having a vertex 9b opposite to the vertex 8b of the first flank face 8, and the second flank face 9 has a downwardly sloping shape greater than that of the first flank face 8, and a third flank face 11 and a fourth flank face 12 having downwardly sloping shapes descending toward the left and right sides of the first flank face 8 and the second flank face 9, respectively. In this embodiment, a downwardly inclined ridgeline 13 exists between the vertex 8b of the first flank 8 and the vertex 9b of the second flank 9. The downwardly inclined first flank 8 has a clearance angle α1, the downwardly inclined second flank 9 has a clearance angle α2, and the ridgeline 13 between the vertices 8b and 9b of the first flank 8 and the second flank 9 has an inclination angle α3. Typically, the clearance angle α1 of the first flank 8 is within a range of 1° to 15°, the clearance angle α2 of the second flank 9 is within a range of 2° to 35°, and the clearance angle α2 of the second flank 9 is larger than the clearance angle α1 of the first flank 8. The inclination angle α3 of the ridgeline 13 is intermediate between the clearance angle α1 of the first flank 8 and the clearance angle α2 of the second flank 9. Preferably, the length L1 of the first flank 8 is 50% or less of the front-to-rear length L of the top surface of the insert 5.

[0025] 4, a chip dividing groove 10 extending rearward from the leading edge 7a may be formed on the fourth flank 12 of the top surface 7 of the tip 5. The chip dividing groove 10 may also be formed on the third flank 11 of the top surface 7.

[0026] Next, as shown in FIGS. 5 to 12, a method for manufacturing the tip 5 in the metal-cutting circular saw 1 having the above-described configuration will be described. The manufacturing method includes a bevel forming step (FIG. 6) in which a side flank portion 23 of a vertically elongated rectangular parallelepiped tip raw material 21 (see FIG. 5) made of, for example, cemented carbide or cermet is provided with a bevel SP1 at a predetermined radial angle θR and a bevel SP2 at a predetermined tangential angle θG, respectively; a mountain-shaped portion forming step (FIG. 7) in which the entire top surface 7 is formed into a mountain-shaped portion 16 by forming left and right inclined surfaces 14 and 15 that descend to both the left and right sides with a center line extending from the center of the front edge 7a to the center of the rear edge 7b of the top surface 7 of the tip raw material 21 as a ridge line 13; and a mountain-shaped portion forming step (FIG. 7) in which the upper part of the mountain-shaped portion 16 is formed. This process includes a first flank forming step (FIG. 10) in which a portion of the first flank 8 is cut along the ridgeline 13 from the leading edge 7a toward the rear in a downwardly sloping manner by a predetermined length, thereby forming the triangular first flank 8 having the leading edge 7a as its base, and a second flank forming step (FIG. 11) in which an upper portion of a mountain-shaped portion 16 extending from the vicinity of the apex 8b of the triangular first flank 8 to the trailing edge 7b is cut in a downwardly sloping manner that is greater than that of the first flank 8, thereby forming an inverted triangular second flank 9 behind the triangular first flank 8. The second flank forming step forms a third flank 11 and a fourth flank 12 that are sloping downward toward the left and right on both the left and right sides of the second flank 9 and the first flank 8. After the second flank forming step (FIG. 11), a chip-separating groove 10 is cut and formed in the third flank 11 on one side of the first flank 8, extending rearward from the leading edge 7a, as shown in FIG.

[0027] 8 and 9, in this embodiment, a rake face forming step is carried out to form the rake face 6 on the upper part of the front surface 22 of the raw chip material 21 in the shape of a vertically elongated rectangular parallelepiped, and then a beveling step is carried out to form chamfered portions 6a on both the left and right sides of the rake face 6. The rake face forming step and beveling step are usually carried out after the mountain-shaped portion forming step (FIG. 7) to form the entire chip top surface 7 into a mountain-shaped portion 16.

[0028] In summary, in this embodiment, the insert 5 is finally manufactured from the insert raw material 21 in the shape of a vertically elongated rectangular parallelepiped shown in Fig. 5 through the inclination forming process shown in Fig. 6, the mountain-shaped portion forming process shown in Fig. 7, the rake face forming process shown in Fig. 8, the bevel processing process shown in Fig. 9, the first flank forming process shown in Fig. 10, and the second flank forming process shown in Fig. 11. Furthermore, if necessary, the chip dividing groove 10 forming process shown in Fig. 12 is further carried out to manufacture the insert 5 with the chip dividing groove 10.

[0029] In this embodiment, in the mountain-shaped portion forming step, the ridge line 13 is formed to slope downward from the leading edge 7a toward the trailing edge 7b of the raw tip material 21, and the ridge line 13 exists between the apex 8b of the first flank 8 and the apex 9b of the second flank 9. However, as shown in Figures 13 and 14, the present invention is not limited to the above-described configuration. That is, a tip 35 according to an embodiment that is a modification of the tip 5 may have a structure in which the apex 28b of the triangular first flank 28 and the apex 29b of the inverted triangular second flank 29 are in direct contact without the ridge line 13 interposed therebetween, rather than being configured to face each other across the ridge line 13 as in the above embodiment.

[0030] Other configurations are the same as those of the above embodiment, and therefore the same reference numerals as those of the above embodiment are used and the description thereof will be omitted. (Cutting performance test)

[0031] Next, a cutting performance test will be described in which a conventional metal-cutting circular saw 41 shown in FIG. 15 is compared with the metal-cutting circular saw 1 of the present invention shown in FIG.

[0032] 15 shows a metal-cutting circular saw 41 in which a generally vertically elongated rectangular parallelepiped tip 45 is fixed by brazing or the like to a base 44 formed on a saw blade 43 of a base metal 42, and a triangular first flank 48 is formed in the center of a front edge 47a of a top surface 47 of the tip 45, with the front edge 47a serving as a base 48a and the apex 48b pointing rearward. Behind the first flank 48 are formed second flank 51 and third flank 52, which slope downward to both the left and right sides of a ridge 53 that extends from the apex 48b of the first flank 48 to the center of the rear edge 47b of the top surface 47. In addition, a chip-separating groove 60 is formed in the third flank 52.

[0033] The specifications of the metal-cutting circular saws 1 and 41 described above were 380 mm outer diameter x 3.0 (2.5) x 37.1H x 52Z (base metal: alloy tool steel, tip: carbide tip), and performance tests were conducted on the conventional metal-cutting circular saw 41 and the metal-cutting circular saw 1 of the present invention under the following conditions: a rotation speed of 300 RPM, a saw feed rate of 600 mm / min, and a cutting test on a workpiece made of steel pipe (STKM) 200 mm x 200 mm x 12.0 t.

[0034] As a result, the cutting life of the conventional metal-cutting circular saw 41 was broken at a cutting area of ​​2.4 m2, whereas the cutting life of the metal-cutting circular saw 1 of the present invention was extended to a cutting area of ​​4.32 m2, confirming approximately 1.8 times the breakage resistance compared to the conventional metal-cutting circular saw 41. In addition, the cut surface of the workpiece was also clearer than that of the conventional metal-cutting circular saw 41, and the time required for the metal-cutting circular saw 1 of the present invention to completely cut the workpiece was reduced by approximately 20% compared to the conventional metal-cutting circular saw 41. Furthermore, as a result of carrying out this cutting performance test on metal-cutting circular saws 1 of various specifications, it was confirmed that the constituent numerical values ​​set forth in claim 5 and / or claim 6 of the present application are suitable.

[0035] In summary, in the cutting performance tests, the metal-cutting circular saw 1 of the present invention produced superior results to the conventional metal-cutting circular saw 41 in terms of chipping resistance, cutting distance, and the beauty of the cut surface. [Industrial Applicability]

[0036] The tip according to the present invention has low cutting resistance to the work material and can perform sufficient cutting work, so it is expected to be widely used in the cutting tool industry for cutting steel pipes and the like. [Explanation of symbols]

[0037] 1 circular saw for metal cutting 2 base money 3 saw blade 4 Pedestal 5 chips 6. Rake face 7 Top surface 7a Leading edge of top surface 7b Trailing edge of top surface 8 First flank 8a Bottom edge of first flank 8b Apex of first flank 9 Second flank 9a Bottom edge of second flank 9b Apex of second flank 10 Groove for dividing chips 11 Third flank 12 Fourth flank

Claims

1. a metal-cutting circular saw tip having a generally rectangular parallelepiped shape overall, the entire top surface being mountain-shaped, a first flank surface sloping downwards in a triangle extending rearward from the central portion of the front edge of the top surface as its base, a second flank surface sloping downwards in an inverted triangle having an apex opposite the apex of the first flank surface and having the rear edge of the top surface as its base, the second flank surface having a greater downward slope than the first flank surface, and third and fourth flank surfaces sloping downwards to the left and right are formed on both the left and right sides of the first and second flank surfaces.

2. 2. The metal-cutting circular saw tip according to claim 1, wherein the apex of the first flank surface and the apex of the second flank surface are in contact with each other.

3. 3. The tip for a metal-cutting circular saw according to claim 1, wherein the side flanks are inclined at a predetermined radial angle and at a predetermined tangential angle.

4. 4. The tip for a metal-cutting circular saw according to claim 3, wherein a rake face having a negative inclination angle is formed on the upper front surface, and chamfers are provided on both left and right sides of said rake face.

5. A metal-cutting circular saw tip as described in claim 1 or claim 2, characterized in that the inclination angle of the first flank is within the range of 1° to 15°, the inclination angle of the second flank is within the range of 2° to 35°, and the inclination angle of the second flank is greater than the inclination angle of the first flank.

6. A tip for a metal-cutting circular saw as described in claim 1 or claim 2, wherein the length of the first relief surface is 50% or less of the front-to-back length of the top surface of the tip.

7. 3. The method for manufacturing a metal-cutting circular saw tip according to claim 1, further comprising: a mountain-shaped portion forming step of forming left and right inclined surfaces that descend in both left and right directions along a center line extending from the center of the leading edge to the center of the trailing edge of a top surface of a vertically elongated rectangular solid-shaped raw tip material, making the entire top surface into a mountain-shaped portion; a first flank surface forming step of cutting a portion of an upper part of the mountain-shaped portion along the ridge line from the leading edge toward the rear by a predetermined length, sloping downwardly, to form a triangular first flank surface with the center of the leading edge as a base; and a second flank surface forming step of cutting an upper part of the mountain-shaped portion from the apex or vicinity of the apex of the triangular first flank surface to the rear edge, sloping downwardly more than the first flank surface, to form an inverted triangular second flank surface rearward of the first triangular flank surface, wherein a third flank surface and a fourth flank surface are formed on both left and right sides of the second flank surface and the first flank surface by the second flank surface forming step.

8. 8. The method for manufacturing a tip for a metal-cutting circular saw according to claim 7, wherein in the mountain-shaped portion forming step, the ridgeline of the mountain-shaped portion is formed to have a downward slope from the leading edge side to the trailing edge side.

9. 9. A method for manufacturing tips for metal-cutting circular saw blades according to claim 7 or 8, characterized in that, before the mountain-shaped portion forming step, a bevel forming step is included in which a predetermined radial angle bevel and a predetermined tangential angle bevel are respectively formed on the side flank surface portions of the tip raw material.

10. 10. The method for manufacturing a tip for a metal-cutting circular saw according to claim 9, further comprising, between the mountain-shaped portion forming step and the first flank surface forming step, a rake face forming step of forming a rake face having a negative inclination angle on the upper front surface of the tip raw material, and a bevel processing step of forming chamfered portions on both left and right sides of the rake face formed by the rake face forming step.

11. A metal-cutting circular saw having saw blades arranged at a predetermined interval on the outer periphery of a base metal and tips fixed to the bases of the saw blades, wherein the tips are the tips described in claim 1 or 2.

Images