Circular saw blade with attached cutter head

Abstract

The circular saw blade (1) has a disc-shaped base (2) with an outer diameter of 200 to 500 mm and a first blade head (11) and a second blade head (13) arranged alternately along the outer periphery of the base (2). The circular saw blade (1) has a blade thickness (1a) of 0.8 mm to 2.0 mm. The first blade head (11) and the second blade head (13) have cutting edges (11c, 13c) and a pair of chamfers (11f) at both ends of the cutting edges (11c, 13c). A first groove (12) and a second groove (14) are formed on the back blade surface in a manner extending from the cutting edges (11c, 13c) in the circumferential direction. The first groove (12) has a first groove bottom (12e), and the first groove bottom (12e) is deepest in the radial direction at a position at a first distance (15a) from the thickness center (7c) in the first thickness direction. The second groove (14) has a second groove bottom (14e), and the second groove bottom (14e) is radially deepest at a position a second distance (15b) from the thickness center (7c) in a second thickness direction opposite to the first thickness direction. The sum of the first distance (15a) and the second distance (15b) is less than 0.35 mm.

Description

Technical Field

[0001] One embodiment of the present disclosure relates to a disc-shaped circular saw blade with a plurality of blade tips attached to the outer circumference, which is used to cut various metal workpieces at high speed. Background Art

[0002] Conventional circular saw cutting machines, for example, are known as devices for high-speed cutting of various metal workpieces using a disc-shaped circular saw blade with a blade thickness of 2 mm. The circular saw blade forms grooves in the workpiece, such as steel or non-steel materials like aluminum, to cut the material. The circular saw blade comprises a disc-shaped base and multiple cutting tips mounted at regular intervals on the base's periphery. The cutting tips are hard tips made of, for example, cemented carbide or cermet.

[0003] The cutter head has a cutting edge extending straight in the thickness direction of the base body and a back cutting surface facing radially outward from the base body. The back cutting surface extends from the cutting edge to the rear of the rotation direction of the circular saw blade at a back angle. A groove for dividing the cutting edge is formed on the back cutting surface. The circular saw blade has a plurality of cutter heads with staggered groove positions. The plurality of cutter heads are arranged in a prescribed order in the circumferential direction of the base body. For example, when the groove is observed from the front cutting surface, a first cutter head having a groove on the left and a second cutter head having a groove on the right are alternately arranged. The cutting edges of the plurality of cutter heads cut the cut material in a prescribed order. Therefore, the chips cut from the cut material are divided by the cutting edges divided by the grooves of each cutter head. Therefore, the actual cutting power of each cutter head can be reduced. As a result, the power required to cut the cut material can be reduced.

[0004] There are cases where circular saw blades with blade thicknesses thinner than 2 mm are used. International Publication No. 2018 / 074038 describes a circular saw blade having a blade thickness of less than 1 mm and a cutter head with grooves formed on the back face. By using a circular saw blade with a thin blade thickness, the amount of chips generated during cutting can be reduced. Moreover, grooves that were previously difficult to provide can be provided on the cutter head provided on a circular saw blade with a blade thickness of less than 1 mm. Therefore, the amount of chips and the cutting resistance can be reduced at the same time. As a result, the power required to cut the material being cut can be further reduced.

[0005] By dividing the chips laterally (in the thickness direction of the base), the asymmetric cutter head due to the groove is repeatedly subjected to lateral forces from the cut material. The cutter head can be displaced laterally (vibrated) by the lateral force. For example, in the case of a thin circular saw blade with a blade thickness of less than 2 mm, the ratio of lateral displacement to the blade thickness tends to become large. Therefore, for example, friction is generated between the side of the cutter head and the cut material. In the portion where frictional heat is generated, the cutter head repeatedly undergoes thermal expansion and thermal contraction. As a result, a notch (heat crack) is generated in the cutter head.

[0006] Sometimes, the material being cut is fed at several times the normal feed rate and cut. The feed rate can be increased by increasing the rotational speed of the circular saw blade or the depth of each cutting edge of the cutter head. Increasing the feed rate further increases the frictional heat generated between the cutter head and the material being cut. Therefore, when using a thin circular saw blade and cutting the material at a high feed rate, the cutter head is susceptible to chipping due to frictional heat. Therefore, in thin circular saw blades with a blade thickness of less than 2 mm, it is desirable to further improve the durability of the cutter head. Summary of the Invention

[0007] Problems to be solved by the invention

[0008] Therefore, in the past, a structure that improves the durability of the cutter head has been desired in a circular saw blade with a thin blade that can feed the cut material at a high speed to cut, for example, by suppressing the generation of chips due to frictional heat to improve the durability of the cutter head.

[0009] Means used to solve problems

[0010] According to one feature of the present disclosure, a circular saw blade with a cutting head includes: a disc-shaped base having an outer diameter of 200 mm to 500 mm; and first and second cutting heads projecting radially from the outer circumference of the base and arranged alternately along the outer circumference of the base. The circular saw blade has a blade thickness of 0.8 mm to 2.0 mm. The first and second cutting heads have a rake face facing forward in the direction of rotation of the circular saw blade, a flank face facing radially outward from the base, and a cutting edge formed between the rake and flank faces. A pair of chamfers are provided at each end of the cutting edge, and a groove is formed on the flank face, extending circumferentially from the cutting edge. The groove of the first cutting head has a first groove bottom, which is radially deepest at a first distance from the thickness center of the cutting edge of the first cutting head in a first thickness direction. The groove of the second cutting head has a second groove bottom, which is radially deepest at a second distance from the thickness center of the cutting edge of the second cutting head in a second thickness direction opposite to the first thickness direction. The sum of the first distance and the second distance is less than 0.35 mm.

[0011] Therefore, the distance between the bottom of the first groove and the bottom of the second groove can be shortened. When the first cutter head cuts the material, a force is applied laterally from the center of the thickness of the cutting edge toward the first thickness direction where the first groove is located. When the second cutter head cuts the material, a force is applied laterally toward the second thickness direction where the second groove is located. By reducing the sum of the first and second distances, the lateral forces acting on the first and second cutter heads can be suppressed. Consequently, the lateral displacement of the first and second cutter heads can be reduced.

[0012] Furthermore, the sum of the first and second distances is reduced to less than 0.35 mm, a smaller value than conventional methods. This reduces lateral displacement of the first and second cutting heads when cutting material at high feed rates using a thin circular saw blade with a blade thickness of less than 2.0 mm. This, for example, reduces frictional heat generated on the side surfaces of the first and second cutting heads, thereby preventing the formation of notches due to frictional heat. This improves the durability of the first and second cutting heads.

[0013] According to other features, the groove has: a pair of groove ends that intersect with the cutting edge, and a pair of inclined surfaces that are provided between any one of the pair of groove ends and the groove bottom and are inclined relative to the cutting edge. At the groove end, the groove end angle between the cutting edge and the inclined surface is 60° to 85°. Therefore, by making the groove end angle less than 85°, the angular shape of the groove end can be set to an obtuse angle. Therefore, for example, compared with the case where the angular shape of the groove end is a right angle, the notch of the groove end can be suppressed. Moreover, by making the groove end angle more than 60°, the sum of the first distance and the second distance can be reduced. Therefore, the lateral displacement of the first cutting head and the second cutting head can be suppressed. As a result, the notch of the first cutting head and the second cutting head caused by frictional heat can be suppressed.

[0014] As a result, the notches at both ends of the cutter head are uniformly distributed. Consequently, the cut surface of the workpiece can be maintained in a state of good machining for a long period of time. Furthermore, the increase in the cutting resistance of the first and second cutter heads to the workpiece can be suppressed. Thus, for example, the generation of frictional heat on the side surfaces of the first and second cutter heads can be suppressed. This extends the service life of the first and second cutter heads.

[0015] According to another feature, the groove includes: a pair of groove ends intersecting the cutting edge; and a pair of inclined surfaces disposed between one of the pair of groove ends and the groove bottom and inclined relative to the cutting edge. At the groove ends, an angle between the cutting edge and the inclined surfaces is greater than an angle of the pair of chamfers relative to the cutting edge.

[0016] According to another feature, the inner edge of the first groove, which is the groove of the first cutting head, is separated from the center of the thickness of the cutting edge of the first cutting head by only a first inner distance. The inner edge of the second groove, which is the groove of the second cutting head, is separated from the center of the thickness of the cutting edge of the second cutting head by only a second inner distance. The sum of the first inner distance and the second inner distance is less than the opening width of the first groove in the cutting edge and less than the opening width of the second groove in the cutting edge. Alternatively, the sum of the first inner distance and the second inner distance is less than half the opening width of the first groove in the cutting edge and less than half the opening width of the second groove in the cutting edge.

[0017] According to another feature, the groove of the first cutting head has a first depth from the cutting edge in the radial direction. The groove of the second cutting head has a second depth from the cutting edge in the radial direction. The first depth and the second depth are both greater than or equal to two times and less than or equal to five times the depth of the pair of chamfers from the cutting edge in the radial direction. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 A side view of a circular saw blade.

[0019] Figure 2 for Figure 1 Enlarged side view of part II.

[0020] Figure 3 This is a partially enlarged top view of the circular saw blade.

[0021] Figure 4 This is a partially enlarged top view of the circular saw blade.

[0022] Figure 5 An enlarged front view of the upper part of the circular saw blade.

[0023] Figure 6 This is a front view schematically showing the relationship between the cutter head and feed when the circular saw blade cuts the workpiece.

[0024] Figure 7 It is a partially enlarged front view of the tool head according to the first embodiment.

[0025] Figure 8 It is a partially enlarged front view of the tool head according to the second embodiment.

[0026] Figure 9 It is a partially enlarged front view of the tool head according to the third embodiment.

[0027] Figure 10 It is a partially enlarged front view of the tool head according to the fourth embodiment.

[0028] Figure 11 It is a partially enlarged front view of the tool head according to the fifth embodiment.

[0029] Figure 12 It is a partially enlarged front view of the tool head according to the sixth embodiment.

[0030] Figure 13 It is a partially enlarged front view of the tool head according to the seventh embodiment.

[0031] Figure 14 It is a partially enlarged front view of the tool head according to the eighth embodiment.

[0032] Figure 15 It is a partially enlarged front view of the tool head of the ninth embodiment.

[0033] Figure 16 It is a partially enlarged front view of the tool head according to the tenth embodiment.

[0034] Figure 17 TABLE 1 is a table showing the relationship between the shape of the groove formed in the tool tip and the lateral displacement of the tool tip.

[0035] Figure 18 Graph showing the relationship between the distance between groove bottoms and the lateral displacement of the tool tip.

[0036] Figure 19 This is a front view schematically showing the cutter head and the material being cut by the cutter head.

[0037] Figure 20 To show Figure 19 Diagram of equivalent stress in the section along line XX-XX.

[0038] Figure 21 To show Figure 19 Equivalent stress diagram in the XX-XX line section.

[0039] Figure 22 To show Figure 19 Equivalent stress diagram in the XX-XX line section.

[0040] Figure 23 To show Figure 19 Equivalent stress diagram in the XX-XX line section.

[0041] Figure 24 To show Figure 19 Equivalent stress diagram in the XX-XX line section.

[0042] Figure 25 This is a table showing the relationship between the shape of the groove formed in the blade tip and the number of thermal cracks generated.

[0043] Figure 26 This is a table showing the relationship between the number of cuts of a workpiece by a circular saw blade and the notch of the cutter head.

[0044] Figure 27 It is a partially enlarged top view of the cutter head of the first embodiment after cutting.

[0045] Figure 28 for Figure 27 An enlarged left side view of a portion of the cutter head is shown.

[0046] Figure 29 for Figure 27 An enlarged partial right view of the cutter head is shown.

[0047] Figure 30 This is a partially enlarged front view of the cutting head of the first embodiment after cutting.

[0048] Figure 31 It is a partially enlarged top view of the cutter head of the first embodiment after cutting.

[0049] Figure 32 for Figure 31 An enlarged left side view of a portion of the cutter head is shown.

[0050] Figure 33 It is a partially enlarged top view of the cutter head of the first embodiment after cutting.

[0051] Figure 34 for Figure 33 An enlarged left side view of a portion of the cutter head is shown.

[0052] Figure 35 for Figure 33 A partially enlarged front view of the cutter head is shown.

[0053] Figure 36 It is a partially enlarged top view of the cutter head of the third embodiment after cutting.

[0054] Figure 37 for Figure 36 An enlarged left side view of a portion of the cutter head is shown. DETAILED DESCRIPTION

[0055] based on Figures 1 to 7 The preferred embodiment of the present disclosure is described. The same reference numerals in the description represent the same elements having the same functions without repeated description. Figure 1 As shown, a circular saw blade 1 comprises a disc-shaped base 2 and a plurality of cutting tips 7 mounted on the outer periphery of the base 2. As the base 2 rotates, each cutting tip 7 forms grooves in the material being cut, ultimately severing it. Examples of the cut material include steel materials such as carbon steel, standard structural rolled steel, chrome-molybdenum steel, stainless steel, and cast iron, as well as non-ferrous metals such as aluminum and aluminum alloys, copper, and copper alloys. The cut material, which may be in the form of a rod, column, tube, or plate, is cut into predetermined lengths by the circular saw blade 1.

[0056] like Figure 1 As shown, a substantially circular mounting hole 3 is provided at the center of the base 2, extending through the base 2 in the thickness direction. The rotating shaft of a circular saw is inserted into the mounting hole 3. Circular saws are used, for example, to cut various metal workpieces at room temperature. When cutting the workpiece, the circular saw blade 1 rotates in direction A and moves relative to the workpiece in direction B. This allows the multiple cutting tips 7 arranged around the periphery of the base 2 to sequentially reach the workpiece.

[0057] like Figure 1As shown, the outer diameter of the circular saw blade 1 is, for example, 200 mm to 500 mm. Preferably, it is 200 mm to 400 mm, more preferably 200 mm to 300 mm, for example, 285 mm. The base 2 is, for example, made of steel. The blade thickness 1a of the circular saw blade 1 (see Figure 7 ) For example, it is 0.8mm to 2.0mm. Preferably, the blade thickness 1a is 0.8mm to 1.0mm. The base 2 has a disc-shaped main body 2a and a plurality of protrusions 4 protruding radially outward from the outer periphery of the main body 2a. The plurality of protrusions 4 are formed at predetermined intervals in the circumferential direction of the outer periphery of the main body 2a. The thickness 2c of the base 2 is slightly smaller than the blade thickness 1a, for example, 0.6 to 1.8mm (see Figure 5 ).

[0058] like Figure 1 、 2 As shown, tooth grooves 5 are formed between adjacent protrusions 4. A tool tip seat 6, open circumferentially and radially outward, is formed on the protrusion 4 at the front in the rotational direction. A tool tip 7 is mounted on each tool tip seat 6. Forty to two hundred tool tips 7 are mounted on the base 2, for example, by brazing.

[0059] like Figure 2 、 3 As shown, the cutter head 7 has a first cutter head 11 and a second cutter head 13 having different structures. The first cutter head 11 and the second cutter head 13 are installed alternately in the circumferential direction of the base 2 and at a prescribed interval. Therefore, the first cutter head 11 and the second cutter head 13 alternately reach the cut material and cut the cut material. The cutter head 7 is, for example, a hard cutter head formed of cemented carbide or cermet. Cemented carbide is obtained, for example, by mixing and sintering tungsten carbide and cobalt as a binder. Cermet is obtained by mixing and sintering TiN, TiC, TiCN, etc. with cobalt as a binder. A coating that improves wear resistance can also be applied to the surface of the cutter head 7.

[0060] like Figure 2 、 3 As shown, the cutter head 7 is a substantially rectangular parallelepiped having a flank surface 11b, 13b facing radially outward. A cutting edge 11c, 13c is formed at one end of the flank surface 11b, 13b. The cutting edge 11c, 13c has a thickness 7d slightly larger than the thickness 2c of the base 2 (see FIG. Figure 5 ). The thickness 7d is, for example, 0.8 mm to 1.1 mm. The cutting head 7 is mounted on the base 2 in such a manner that the thickness center 7c of the cutting head 7 is arranged at the center of the base 2, i.e., the thickness center 2b, in the thickness direction. The cutting edges 11c, 13c are located at the front end of the flank surfaces 11b, 13b in the rotation direction and extend in the thickness direction of the base 2. The clearance angle 7b between the circumferential tangent of the base 2 at the cutting edges 11c, 13c and the flank surfaces 11b, 13b is, for example, 5° to 15°.

[0061] like Figure 2 As shown, the cutter head 7 has rake faces 11a, 13a extending from the cutting edges 11c, 13c toward the center of the base 2. In other words, the cutting edges 11c, 13c are formed at the intersection of the flank faces 11b, 13b and the rake faces 11a, 13a. The rake angle 7a of the rake faces 11a, 13a, which are inclined radially relative to the base 2, is -30° to 10°. The cutter head 7 has a recess 7e at a position forward in the direction of rotation and radially inward of the rake faces 11a, 13a. When viewed from the side, the recess 7e is recessed from the rake faces 11a, 13a toward the center of the cutter head 7.

[0062] like Figure 4 、 5 As shown, the first cutting head 11 has a left side 11d and a right side 11e at both ends of the back cutting surface 11b in the thickness direction. The left side 11d and the right side 11e have an angle of 0° to 2° relative to the radial direction of the base 2, for example, an inward inclination angle of 30' (side centripetal angle). The left side 11d and the right side 11e reduce the contact area with the cut material by this slight inclination. Therefore, the cutting resistance is reduced. Moreover, since the left side 11d and the right side 11e are inclined so as not to be excessively protruding relative to the cut surface of the cut material, the processing of the cut surface can be made smooth.

[0063] like Figure 4 、 5 As shown, a chamfer 11f is formed between the back face 11b and the left side face 11d or the right side face 11e. The chamfer 11f is inclined relative to the back face 11b, for example, with a chamfer angle 11g of 45° (see Figure 7 The left and right chamfers 11f have approximately the same chamfer angle relative to the flank 11b. The left and right chamfers 11f are symmetrically arranged about the thickness center 7c. The chamfers 11f are formed flat along the entire length of the end edge of the flank 11b. The thickness-direction width of the chamfers 11f is, for example, 0.05 mm to 0.1 mm, and is approximately the same width along the entire length.

[0064] like Figure 4 、 5As shown, a first groove 12 extending in the circumferential direction is formed on the back cutting surface 11b of the first cutting head 11. The first groove 12 extends from one end of the back cutting surface 11b, namely the cutting edge 11c, to the rear end of the back cutting surface 11b in the rotation direction. The first groove 12 is arranged to the left of the thickness center 7c (first thickness direction). When viewed from the front in the rotation direction of the circular saw blade 1, the first groove 12 is roughly V-shaped. The first groove 12 has a roughly planar inner inclined surface 12c and an outer inclined surface 12d that are inclined relative to the cutting edge 11c. The inner inclined surface 12c is arranged at a position closer to the thickness center 7c than the outer inclined surface 12d. When viewed from the front in the rotation direction of the circular saw blade 1, the inner inclined surface 12c and the outer inclined surface 12d are connected by a first groove bottom 12e having a roughly arc-shaped curved surface. The first groove bottom 12e is located to the left of the thickness center 7c.

[0065] like Figure 7 As shown, the first groove 12 has an inner groove end 12a and an outer groove end 12b located at the cutting edge 11c. The inner groove end 12a is arranged at the intersection of the cutting edge 11c and the inner inclined surface 12c. The outer groove end 12b is arranged at the intersection of the cutting edge 11c and the outer inclined surface 12d. The inner groove end 12a is located to the left of the thickness center 7c. The outer groove end 12b is located at a position farther from the thickness center 7c than the inner groove end 12a. At the inner groove end 12a, there is an inner groove end angle 12f between the inner inclined surface 12c and the cutting edge 11c. At the outer groove end 12b, there is an outer groove end angle 12g between the outer inclined surface 12d and the cutting edge 11c. The inner groove end angle 12f and the outer groove end angle 12g are the same size, which is 65°. The first groove 12 is a shape symmetrical in the thickness direction with the first groove bottom 12e as the center. A groove bottom angle 12h between the inner inclined surface 12c and the outer inclined surface 12d is 50°.

[0066] like Figure 3 、 7 As shown, a second groove 14 is formed on the back cutting surface 13b of the second cutting head 13, extending circumferentially from the cutting edge 13c to the rear end of the back cutting surface 13b in the rotation direction. The second groove 14 is symmetrical with the first groove 12 with respect to the thickness center 7c and is arranged at a position symmetrical with the first groove 12. The second groove 14 is arranged to the right of the thickness center 7c (in the second thickness direction). The second groove 14 has a roughly planar inner inclined surface 14c and an outer inclined surface 14d that are inclined relative to the cutting edge 13c. The inner inclined surface 14c is arranged at a position closer to the thickness center 7c than the outer inclined surface 14d. The inner inclined surface 14c and the outer inclined surface 14d are connected by the second groove bottom 14e to form a roughly V-shape. When viewed from the front in the rotation direction of the circular saw blade 1, the second groove bottom 14e is a roughly arc-shaped curved surface. The second groove bottom 14e is located to the right of the thickness center 7c.

[0067] like Figure 7 As shown, the second groove 14 has an inner groove end 14a at the intersection of the cutting edge 13c and the inner inclined surface 14c. The second groove 14 has an outer groove end 14b at the intersection of the cutting edge 13c and the outer inclined surface 14d. The inner groove end 14a is located to the right of the thickness center 7c. The outer groove end 14b is set at a position farther away from the thickness center 7c than the inner groove end 14a. The inner groove end angle between the inner inclined surface 14c and the cutting edge 13c is the same as the inner groove end angle 12f, which is 65°. The outer groove end angle between the outer inclined surface 14d and the cutting edge 13c is the same as the outer groove end angle 12g, which is 65°. The groove bottom angle between the inner inclined surface 14c and the outer inclined surface 14d is the same as the groove bottom angle 12h, which is 50°.

[0068] like Figure 7 As shown, the distance 16 between the inner groove end 12a and the inner groove end 14a is greater than 0 mm, for example, 0.04 mm. There is a first distance 15a between the first groove bottom 12e and the thickness center 7c. There is a second distance 15b between the second groove bottom 14e and the thickness center 7c. The first distance 15a and the second distance 15b are the same in size. The distance 15 between the groove bottoms, which is the sum of the first distance 15a and the second distance 15b, is less than 0.35 mm. It is preferably less than 0.30 mm, for example, 0.28 mm. The first distance 15a and the second distance 15b are formed in the first groove bottom 12e and the second groove bottom 14e in the base 2 (refer to Figure 5 The groove width of the first groove 12 and the second groove 14 is, for example, 0.26 mm.

[0069] like Figure 6 As shown, the chips 9 cut from the workpiece by the first cutting head 11 are divided into chips 9a and 9b by the first groove 12. The first groove 12 is located to the left of the thickness center 7c. Therefore, the width of the chip 9a on the left becomes smaller than the chip 9b on the right. The cutting resistance from the workpiece to the right of the first groove 12 of the chip 9b with a large cutting width is greater than the cutting resistance from the workpiece to the left of the first groove 12 of the chip 9a with a small cutting width. The first cutting head 11 can be displaced in the left and right directions due to the cutting resistance. The lateral displacement of the first cutting head 11 generates friction between the left side 11d or the right side 11e and the workpiece. Since there is a difference in the size of the cutting resistance of the left and right cutting edges 11c, the friction heat generated on the right side 11e tends to become greater than that on the left side 11d. Therefore, there is a tendency that frictional heat generated at the intersection of the right side surface 11 e and the chamfer 11 f is greater, and frictional heat generated at the intersection of the left side surface 11 d and the chamfer 11 f is greater.

[0070] like Figure 6As shown, the intersections of the left and right ends of the cutting edge 11c and the pair of chamfers 11f form obtuse angles. Therefore, friction with the workpiece caused by lateral displacement is relatively suppressed at the intersections of the left and right ends of the cutting edge 11c and the chamfers 11f. Compared to the first cutting head 11, the chips removed from the workpiece by the second cutting head 13 rotate left and right about the thickness center 7c. Consequently, there is a tendency for greater frictional heat to be generated at the intersection of the left side 13d and the chamfers 13f, followed by greater frictional heat at the intersection of the right side 13e and the chamfers 13f.

[0071] like Figure 7 As shown, the sum of the first distance 15a and the second distance 15b is less than 0.35mm, for example, 0.28mm. Therefore, the chips 9a with small width (refer to Figure 6 ) and the width of the chips 9b with a large width becomes smaller. Therefore, the difference in cutting resistance in the left and right directions (width direction) of the cutting edges 11c and 13c becomes smaller, and the lateral displacement of the cutter head 7 can be suppressed. As a result, the frictional heat generated between the left side 11d or the right side 11e and the cut material can be suppressed. Therefore, the notch caused by frictional heat can be suppressed on the left side 11d or the right side 11e. The inner groove end angle 12f and the outer groove end angle 12g are greater than 60°, for example, 65°. Therefore, the distance between the first groove bottom 12e and the second groove bottom 14e can be shortened. Thus, it is easy to set the first groove 12 and the second groove 14 in such a way that the sum of the first distance 15a and the second distance 15b is less than 0.35 mm.

[0072] As mentioned above, Figure 1 、 5 As shown, the circular saw blade 1 comprises a disc-shaped base 2 with an outer diameter of 200 mm to 500 mm, and first and second cutting heads 11, 13 radially protruding from the outer periphery of the base 2 and arranged alternately along the outer periphery of the base 2. The circular saw blade 1 has a blade thickness 1a of 0.8 mm to 2.0 mm. The first and second cutting heads 11, 13 have rake faces 11a, 13a facing forward in the direction of rotation of the circular saw blade 1, flank faces 11b, 13b facing radially outward of the base 2, and cutting edges 11c, 13c formed between the rake faces 11a, 13a and the flank faces 11b, 13b. A pair of chamfers 11f, 13f are formed at each end of the cutting edges 11c, 13c, and first and second grooves 12, 14 are formed on the flank faces 11b, 13b, extending circumferentially from the cutting edges 11c, 13c.

[0073] like Figure 7As shown, the first groove 12 of the first cutting head 11 has a first groove bottom 12e that is radially deepest at a position a first distance 15a from the thickness center 7c of the cutting edge 11c of the first cutting head 11 in the first thickness direction. The second groove 14 of the second cutting head 13 has a second groove bottom 14e that is radially deepest at a position a second distance 15b from the thickness center 7c of the cutting edge 13c of the second cutting head 13 in a second thickness direction opposite to the first thickness direction. The sum of the first distance 15a and the second distance 15b, i.e., the groove bottom distance 15, is 0.35 mm or less.

[0074] Therefore, the distance between the first groove bottom 12e and the second groove bottom 14e can be shortened. When cutting the workpiece, the first cutting head 11 is subjected to a lateral force in the first thickness direction, toward the location of the first groove 12. When cutting the workpiece, the second cutting head 13 is subjected to a lateral force in the second thickness direction, toward the location of the second groove 14. By reducing the sum of the first distance 15a and the second distance 15b, the lateral forces acting on the first and second cutting heads 11, 13 can be suppressed. Consequently, lateral displacement of the first and second cutting heads 11, 13 can be suppressed.

[0075] Furthermore, the sum of the first distance 15a and the second distance 15b is smaller than conventional methods, at a value of 0.35 mm or less. This allows for the use of a thin circular saw blade 1 with a blade thickness 1a of 2.0 mm or less, for example, when cutting a workpiece at a feed rate 2.5 times or higher than that of conventional cutting operations. Consequently, for example, the generation of frictional heat on the left sides 11d, 13d and right sides 11e, 13e of the first and second cutting heads 11, 13 can be suppressed, thereby preventing the formation of chipping caused by frictional heat. This improves the durability of the first and second cutting heads 11, 13.

[0076] like Figure 7 As shown, the first and second grooves 12 and 14 have a pair of inner groove ends 12a and 14a and outer groove ends 12b and 14b that intersect the cutting edges 11c and 13c. A pair of inner inclined surfaces 12c and 14c and outer inclined surfaces 12d and 14d are provided between the groove bottoms 12e and 14e, respectively, and are inclined relative to the cutting edges 11c and 13c. At the inner groove end 12a, the inner groove end angle 12f between the cutting edge 11c and the inner inclined surface 12c is between 60° and 85°. At the outer groove end 12b, the outer groove end angle 12g between the cutting edge 11c and the outer inclined surface 12d is between 60° and 85°.

[0077] Therefore, by setting the inner groove end angle 12f and the outer groove end angle 12g to less than 85°, the angle between the inner groove end 12a and the outer groove end 12b can be set to an obtuse angle. Therefore, compared to a case where the groove end angle is a right angle, for example, notches between the inner groove end 12a and the outer groove end 12b can be suppressed. Furthermore, by setting the inner groove end angle 12f and the outer groove end angle 12g to more than 60°, the sum of the first distance 15a and the second distance 15b can be reduced. Therefore, lateral displacement of the first and second cutting heads 11, 13 can be suppressed. Consequently, notches between the first and second cutting heads 11, 13 caused by frictional heat can be suppressed.

[0078] Therefore, there is no variation in the formation of notches at the ends of the first and second cutting heads 11, 13. Consequently, the state in which the cut surface of the workpiece can be well machined can be maintained for a long period of time. Furthermore, the increase in the cutting resistance of the first and second cutting heads 11, 13 to the workpiece can be suppressed. Therefore, for example, the generation of frictional heat on the left sides 11d, 13d and right sides 11e, 13e of the first and second cutting heads 11, 13 can be suppressed. This extends the service life of the first and second cutting heads 11, 13.

[0079] Then, based on Figure 8 The second embodiment of the present disclosure is described. The circular saw blade 20 has a first blade head 21 and a second blade head 23, which replace Figure 7 The first cutting head 11 and the second cutting head 13 are shown. The first cutting head 21 has a first groove 22 extending from the cutting edge 21a in the circumferential direction to replace Figure 7 The second cutting head 23 has a second groove 24 extending circumferentially from the cutting edge 23a, replacing the first groove 12. Figure 7 The second slot 14 is shown.

[0080] like Figure 8 As shown, the first groove 22 is provided in the first thickness direction to the left of the thickness center 7c. When viewed from the front in the rotational direction of the circular saw blade 20, the first groove 22 has a generally bilaterally symmetrical V-shaped shape. The first groove 22 includes a generally planar inner inclined surface 22c and an outer inclined surface 22d, which are inclined relative to the cutting edge 21a. The inner inclined surface 22c is provided closer to the thickness center 7c than the outer inclined surface 22d. When viewed from the front in the rotational direction of the circular saw blade 20, the inner inclined surface 22c and the outer inclined surface 22d are connected by a first groove bottom 22e having a generally arcuate curved surface.

[0081] like Figure 8As shown, an inner groove end 22a is provided at the intersection of the cutting edge 21a and the inner inclined surface 22c. An outer groove end 22b is provided at the intersection of the cutting edge 21a and the outer inclined surface 22d. At the inner groove end 22a, an inner groove end angle 22f is formed between the inner inclined surface 22c and the cutting edge 21a. At the outer groove end 22b, an outer groove end angle 22g is formed between the outer inclined surface 22d and the cutting edge 21a. The inner groove end angle 22f and the outer groove end angle 22g are the same, 75°. The groove bottom angle 22h between the inner inclined surface 22c and the outer inclined surface 22d is 30°.

[0082] like Figure 8 As shown, the second groove 24 is symmetrical with the first groove 22 relative to the thickness center 7c and is located at a position symmetrical to the first groove 22. The second groove 24 is located in the second thickness direction to the right of the thickness center 7c. The second groove 24 has a substantially planar inner inclined surface 24c and an outer inclined surface 24d that are inclined relative to the cutting edge 23a. The inner inclined surface 24c is located closer to the thickness center 7c than the outer inclined surface 24d. When viewed from the front in the direction of rotation of the circular saw blade 20, the inner inclined surface 24c and the outer inclined surface 24d are connected by a second groove bottom 24e having a substantially arcuate curved surface.

[0083] like Figure 8 As shown, an inner groove end 24a is provided at the intersection of the cutting edge 23a and the inner inclined surface 24c. An outer groove end 24b is provided at the intersection of the cutting edge 23a and the outer inclined surface 24d. The inner groove end angle between the inner inclined surface 24c and the cutting edge 23a is the same as the inner groove end angle 22f, which is 75°. The outer groove end angle between the outer inclined surface 24d and the cutting edge 23a is the same as the outer groove end angle 22g, which is 75°.

[0084] like Figure 8 As shown, the inter-groove end distance 16 between the inner groove end 22a and the inner groove end 24a is, for example, 0.04 mm. The first distance 25a between the first groove bottom 22e and the thickness center 7c is the same as the second distance 25b between the second groove bottom 24e and the thickness center 7c. The inter-groove bottom distance 25, which is the sum of the first distance 25a and the second distance 25b, is 0.35 mm or less. Preferably, it is 0.30 mm or less, for example, 0.26 mm. The groove width of the first groove 22 and the second groove 24 is 0.22 mm.

[0085] Then, based on Figure 9 The third embodiment of the present disclosure is described. The circular saw blade 30 has a first blade head 31 and a second blade head 33, which replace the first blade head 31 and the second blade head 33. Figure 7The first cutting head 11 and the second cutting head 13 are shown. The first cutting head 31 has a first groove 32 extending from the cutting edge 31a in the circumferential direction to replace Figure 7 The second cutting head 33 has a second groove 34 extending circumferentially from the cutting edge 33a, replacing the first groove 12. Figure 7 The second slot 14 is shown.

[0086] like Figure 9 As shown, the first groove 32 is provided in the first thickness direction to the left of the thickness center 7c. When viewed from the front in the rotational direction of the circular saw blade 30, the first groove 32 has a generally bilaterally symmetrical V-shaped shape. The first groove 32 includes a generally planar inner inclined surface 32c and an outer inclined surface 32d, both inclined relative to the cutting edge 31a. The inner inclined surface 32c is located closer to the thickness center 7c than the outer inclined surface 32d. When viewed from the front in the rotational direction of the circular saw blade 30, the inner inclined surface 32c and the outer inclined surface 32d are connected by a first groove bottom 32e having a generally arcuate curved surface.

[0087] like Figure 9 As shown, an inner groove end 32a is provided at the intersection of the cutting edge 31a and the inner inclined surface 32c. An outer groove end 32b is provided at the intersection of the cutting edge 31a and the outer inclined surface 32d. At the inner groove end 32a, an inner groove end angle 32f is formed between the inner inclined surface 32c and the cutting edge 31a. At the outer groove end 32b, an outer groove end angle 32g is formed between the outer inclined surface 32d and the cutting edge 31a. The inner groove end angle 32f and the outer groove end angle 32g are the same, 55°. The groove bottom angle 32h between the inner inclined surface 32c and the outer inclined surface 32d is 70°.

[0088] like Figure 9 As shown, the second groove 34 is symmetrically shaped with the first groove 32 relative to the thickness center 7c and is located at a position symmetrical to the first groove 32. The second groove 34 is located in the second thickness direction to the right of the thickness center 7c. The second groove 34 has a substantially planar inner inclined surface 34c and an outer inclined surface 34d that are inclined relative to the cutting edge 33a. The inner inclined surface 34c is located closer to the thickness center 7c than the outer inclined surface 34d. When viewed from the front in the direction of rotation of the circular saw blade 30, the inner inclined surface 34c and the outer inclined surface 34d are connected by a second groove bottom 34e having a substantially arcuate curved surface.

[0089] like Figure 9As shown, an inner groove end 34a is provided at the intersection of the cutting edge 33a and the inner inclined surface 34c. An outer groove end 34b is provided at the intersection of the cutting edge 33a and the outer inclined surface 34d. The inner groove end angle between the inner inclined surface 34c and the cutting edge 33a is the same as the inner groove end angle 32f, which is 55°. The outer groove end angle between the outer inclined surface 34d and the cutting edge 33a is the same as the outer groove end angle 32g, which is 55°. The inter-groove end distance 16 between the inner groove end 32a and the inner groove end 34a is, for example, 0.04 mm. The first distance 35a between the first groove bottom 32e and the thickness center 7c is the same as the second distance 35b between the second groove bottom 34e and the thickness center 7c. The inter-groove bottom distance 35, which is the sum of the first distance 35a and the second distance 35b, is less than 0.35 mm, for example, 0.34 mm. The groove width of the first groove 32 and the second groove 34 is 0.32 mm.

[0090] Then, based on Figure 10 The fourth embodiment of the present disclosure is described. The circular saw blade 40 has a first blade head 41 and a second blade head 43, which replace the first blade head 41 and the second blade head 43. Figure 7 The first cutting head 11 and the second cutting head 13 are shown. The first cutting head 41 has a first groove 42 extending from the cutting edge 41a in the circumferential direction to replace Figure 7 The second cutting head 43 has a second groove 44 extending circumferentially from the cutting edge 43a, replacing the first groove 12. Figure 7 The second slot 14 is shown.

[0091] like Figure 10 As shown, the first groove 42 is arranged in the first thickness direction to the left of the thickness center 7c. When viewed from the front in the rotation direction of the circular saw blade 40, the first groove 42 is a roughly U-shaped shape that is symmetrical on both sides. The first groove 42 has a roughly planar inner rising surface 42c and an outer rising surface 42e that are orthogonal to the cutting edge 41a. The inner rising surface 42c is arranged at a position closer to the thickness center 7c than the outer rising surface 42e. The inner rising surface 42c and the outer rising surface 42e are smoothly connected to the inner inclined surface 42d and the outer inclined surface 42f on the side close to the center of the base 2 (below the figure). When viewed from the front in the rotation direction of the circular saw blade 40, the inner inclined surface 42d and the outer inclined surface 42f are roughly arc-shaped curved surfaces. In other words, the inner inclined surface 42d and the outer inclined surface 42f include surfaces that are inclined relative to the cutting edge 41a. At the center of the first groove 42 , the inner inclined surface 42 d and the outer inclined surface 42 f are connected by a first groove bottom 42 g .

[0092] like Figure 10As shown, an inner groove end 42a is provided at the intersection of the cutting edge 41a and the inner rising surface 42c. An outer groove end 42b is provided at the intersection of the cutting edge 41a and the outer rising surface 42e. The inner groove end angle between the inner rising surface 42c and the cutting edge 41a and the outer groove end angle between the outer rising surface 42e and the cutting edge 41a are 90 degrees. The groove width 42h of the first groove 42 is less than 0.30mm. The first groove 42 is formed with a groove width of 42h less than 0.30mm. Figure 7 The first grooves 12 shown are formed with substantially the same groove depth.

[0093] like Figure 10 As shown, the second groove 44 is symmetrical with the first groove 42 relative to the thickness center 7c and is located at a position symmetrical with the first groove 42. The second groove 44 is located in the second thickness direction to the right of the thickness center 7c. The second groove 44 has a substantially planar inner rising surface 44c and an outer rising surface 44e that are orthogonal to the cutting edge 43a. The inner rising surface 44c is located closer to the thickness center 7c than the outer rising surface 44e. The inner rising surface 44c and the outer rising surface 44e are smoothly connected to the inner inclined surface 44d and the outer inclined surface 44f on the side near the center of the base 2. When viewed from the front in the rotation direction of the circular saw blade 40, the inner inclined surface 44d and the outer inclined surface 44f are substantially arc-shaped curved surfaces. At the center of the second groove 44, the inner inclined surface 44d and the outer inclined surface 44f are connected by a second groove bottom 44g.

[0094] like Figure 10 As shown, an inner groove end 44a is provided at the intersection of the cutting edge 43a and the inner raised surface 44c. An outer groove end 44b is provided at the intersection of the cutting edge 43a and the outer raised surface 44e. The inner groove end 44a is located to the right of the thickness center 7c. The inter-groove end distance 16 between the inner groove end 42a and the inner groove end 44a is, for example, 0.04 mm. The first distance 45a between the first groove bottom 42g and the thickness center 7c is the same as the second distance 45b between the second groove bottom 44g and the thickness center 7c. The inter-groove bottom distance 45, which is the sum of the first distance 45a and the second distance 45b, is 0.35 mm or less. It is preferably 0.30 mm or less, for example, 0.20 mm.

[0095] Then, based on Figure 11 The fifth embodiment of the present disclosure is described. The circular saw blade 50 has a first blade head 51 and a second blade head 53, which replace Figure 7 The first cutting head 11 and the second cutting head 13 are shown. The first cutting head 51 has a first groove 52 extending from the cutting edge 51a in the circumferential direction to replace Figure 7 The second cutting head 53 has a second groove 54 extending circumferentially from the cutting edge 53a, replacing the first groove 12. Figure 7 The second slot 14 is shown.

[0096] like Figure 11 As shown, the first groove 52 is arranged in the first thickness direction to the left of the thickness center 7c. When viewed from the front in the rotation direction of the circular saw blade 50, the first groove 52 is a shape in which a roughly V-shaped and a roughly U-shaped shape that are symmetrical on both sides are arranged and connected in the radial direction of the base 2. The first groove 52 has a roughly planar inner inclined surface 52c and an outer inclined surface 52f that are inclined relative to the cutting edge 51a. The inner inclined surface 52c is arranged at a position closer to the thickness center 7c than the outer inclined surface 52f. The inner inclined surface 52c is connected to the inner U surface 52e at the inner U end 52d on the side close to the center of the base 2 (below the figure). The outer inclined surface 52f is connected to the outer U surface 52h at the outer U end 52g on the side close to the center of the base 2.

[0097] like Figure 11 As shown, in the upper portion of the diagram near the cutting edge 51a, a portion of the inner U-shaped surface 52e and the outer U-shaped surface 52h has a roughly flat surface orthogonal to the cutting edge 51a. In addition, in the lower portion of the diagram away from the cutting edge 51a, a portion of the inner U-shaped surface 52e and the outer U-shaped surface 52h has a roughly arc-shaped curved surface. The inner U-shaped surface 52e and the outer U-shaped surface 52h are connected by the first groove bottom 52i at the center of the first groove 52. The inner U-shaped surface 52e and the outer U-shaped surface 52h are symmetrical with respect to the first groove bottom 52i as the center. The U-shaped groove width 52n of the roughly U-shaped groove formed by the inner U-shaped surface 52e and the outer U-shaped surface 52h is 0.12mm.

[0098] like Figure 11 As shown, an inner groove end 52a is provided at the intersection of the cutting edge 51a and the inner inclined surface 52c. An outer groove end 52b is provided at the intersection of the cutting edge 51a and the outer inclined surface 52f. At the inner groove end 52a, an inner groove end angle 52j is formed between the inner inclined surface 52c and the cutting edge 51a. At the outer groove end 52b, an outer groove end angle 52k is formed between the outer inclined surface 52f and the cutting edge 51a. The inner groove end angle 52j and the outer groove end angle 52k are the same, 55°. The groove bottom angle 52m between the inner inclined surface 52c and the outer inclined surface 52f is 70°.

[0099] like Figure 11As shown, the second groove 54 is symmetrical with the first groove 52 relative to the thickness center 7c and is located at a position symmetrical with the first groove 52. The second groove 54 is located in the second thickness direction to the right of the thickness center 7c. The second groove 54 has a substantially planar inner inclined surface 54c and an outer inclined surface 54f that are inclined relative to the cutting edge 53a. The inner inclined surface 54c is located closer to the thickness center 7c than the outer inclined surface 54f. The inner inclined surface 54c is connected to the inner U-shaped surface 54e at the inner U-shaped end 54d on the side closer to the center of the base 2. The outer inclined surface 54f is connected to the outer U-shaped surface 54h at the outer U-shaped end 54g on the side closer to the center of the base 2. The inner U-shaped surface 54e and the outer U-shaped surface 54h are connected at the center of the second groove 54 by the second groove bottom 54i.

[0100] like Figure 11 As shown, an inner groove end 54a is provided at the intersection of the cutting edge 53a and the inner inclined surface 54c. An outer groove end 54b is provided at the intersection of the cutting edge 53a and the outer inclined surface 54f. The inner groove end angle between the inner inclined surface 54c and the cutting edge 53a is the same as the inner groove end angle 52j, which is 55°. The outer groove end angle between the outer inclined surface 54f and the cutting edge 53a is the same as the outer groove end angle 52k, which is 55°. The groove end distance 16 between the inner groove end 52a and the inner groove end 54a is, for example, 0.04mm. The first distance 55a between the first groove bottom 52i and the thickness center 7c is the same as the second distance 55b between the second groove bottom 54i and the thickness center 7c. The groove bottom distance 55, which is the sum of the first distance 55a and the second distance 55b, is less than 0.35mm, for example, 0.30mm. The groove width of the first groove 52 and the second groove 54 is, for example, Figure 9 In the case where the groove depths of the circular saw blade 30 shown are the same, they are set to be smaller than the groove widths of the first groove 32 and the second groove 34 .

[0101] Then, based on Figure 12 The sixth embodiment of the present disclosure is described. The circular saw blade 60 has a first blade head 61 and a second blade head 63, which replace Figure 7 The first cutting head 11 and the second cutting head 13 are shown. The first cutting head 61 has a first groove 62 extending from the cutting edge 61a in the circumferential direction to replace Figure 7 The second cutting head 63 has a second groove 64 extending circumferentially from the cutting edge 63a, replacing the first groove 12. Figure 7 The second slot 14 is shown.

[0102] like Figure 12As shown, the first groove 62 is provided in the first thickness direction to the left of the thickness center 7c. When viewed from the front in the rotation direction of the circular saw blade 60, the first groove 62 has a left-right symmetrical elliptical shape, specifically, a shape that is half of an elliptical shape or a part of an elliptical shape. The first groove 62 has an inner inclined surface 62c and an outer inclined surface 62d that form a curved surface of an elliptical surface. The inner inclined surface 62c is provided at a position closer to the thickness center 7c than the outer inclined surface 62d. The inner inclined surface 62c and the outer inclined surface 62d are connected in the center of the first groove 62 by the first groove bottom 62e. The inner inclined surface 62c and the outer inclined surface 62d are left-right symmetrical shapes with the first groove bottom 62e as the center. The groove width 62f of the first groove 62 is equal to Figure 10 The first groove 42 shown is the same as that of the first groove 42, which is 0.16 mm. Figure 7 The first grooves 12 shown are formed with substantially the same groove depth.

[0103] like Figure 12 As shown, an inner groove end 62a is provided at the intersection of the cutting edge 61a and the inner inclined surface 62c. An outer groove end 62b is provided at the intersection of the cutting edge 61a and the outer inclined surface 62d. At the inner groove end 62a, the inner inclined surface 62c is roughly perpendicular to the cutting edge 61a. At the outer groove end 62b, the outer inclined surface 62d is roughly perpendicular to the cutting edge 61a. At the first groove bottom 62e, the tangent of the inner inclined surface 62c and the outer inclined surface 62d is roughly parallel to the cutting edge 61a. In other words, between the inner groove end 62a or the outer groove end 62b and the first groove bottom 62e, the inner inclined surface 62c and the outer inclined surface 62d include surfaces that are inclined relative to the cutting edge 61a.

[0104] like Figure 12 As shown, the second groove 64 is symmetrically shaped with the first groove 62 relative to the thickness center 7c and is located at a position symmetrical to the first groove 62. The second groove 64 is located in the second thickness direction to the right of the thickness center 7c. The second groove 64 has a curved inner inclined surface 64c and an outer inclined surface 64d. The inner inclined surface 64c is located closer to the thickness center 7c than the outer inclined surface 64d. The inner inclined surface 64c and the outer inclined surface 64d are connected at the center of the second groove 64 by a second groove bottom 64e.

[0105] like Figure 12As shown, an inner groove end 64a is provided at the intersection of the cutting edge 63a and the inner inclined surface 64c. An outer groove end 64b is provided at the intersection of the cutting edge 63a and the outer inclined surface 64d. The inner groove end 64a is located to the right of the thickness center 7c. At the inner groove end 64a, the inner inclined surface 64c is approximately perpendicular to the cutting edge 63a. At the outer groove end 64b, the outer inclined surface 64d is approximately perpendicular to the cutting edge 63a. The inter-groove end distance 16 between the inner groove end 62a and the inner groove end 64a is, for example, 0.04 mm. The first distance 65a between the first groove bottom 62e and the thickness center 7c is the same as the second distance 65b between the second groove bottom 64e and the thickness center 7c. The inter-groove bottom distance 65, which is the sum of the first distance 65a and the second distance 65b, is less than 0.35 mm, for example, 0.20 mm.

[0106] Then, based on Figure 13 The seventh embodiment of the present disclosure is described. The circular saw blade 70 has a first blade head 71 and a second blade head 73, which replace Figure 7 The first cutting head 11 and the second cutting head 13 are shown. The first cutting head 71 has a first groove 72 extending from the cutting edge 71a in the circumferential direction to replace Figure 7 The second cutting head 73 has a second groove 74 extending circumferentially from the cutting edge 73a, replacing the first groove 12. Figure 7 The second slot 14 is shown.

[0107] like Figure 13 As shown, the first groove 72 is provided in the first thickness direction to the left of the thickness center 7c. When viewed from the front in the rotation direction of the circular saw blade 70, the first groove 72 is a substantially V-shaped shape that is bilaterally symmetrical. The first groove 72 has a substantially planar inner inclined surface 72c and an outer inclined surface 72d that are inclined relative to the cutting edge 71a. The inner inclined surface 72c and the outer inclined surface 72d are connected by a first groove bottom 72e. The inner inclined surface 72c, the outer inclined surface 72d, and the first groove bottom 72e have a substantially planar shape that is inclined relative to the cutting edge 71a. Figure 7 The inner inclined surface 12c, the outer inclined surface 12d, and the first groove bottom 12e shown have the same shape.

[0108] like Figure 13 As shown, an inner groove end 72a is provided at the intersection of the cutting edge 71a and the inner inclined surface 72c. An outer groove end 72b is provided at the intersection of the cutting edge 71a and the outer inclined surface 72d. When viewed from the front in the direction of rotation of the circular saw blade 70, the inner groove end 72a and the outer groove end 72b have substantially arc-shaped rounded corners (rounded corners). The radius of the rounded corners is, for example, 0.01 to 0.05 mm.

[0109] like Figure 13As shown, an inner groove end angle 72f is defined between the inner inclined surface 72c and the cutting edge 71a. An outer groove end angle 72g is defined between the outer inclined surface 72d and the cutting edge 71a. The inner groove end angle 72f and the outer groove end angle 72g correspond to the angles between the tangent lines at the lower ends of the inner groove ends 72a and outer groove ends 72b shown in the figure and the cutting edge 71a. The inner groove end angle 72f and the outer groove end angle 72g are equal in magnitude, at 65°. The groove bottom angle 72h between the inner inclined surface 72c and the outer inclined surface 72d is 50°.

[0110] like Figure 13 As shown, the second groove 74 is symmetrical with the first groove 72 relative to the thickness center 7c and is located at a position symmetrical to the first groove 72. The second groove 74 is located to the right of the thickness center 7c in the second thickness direction. The second groove 74 has a substantially planar inner inclined surface 74c and an outer inclined surface 74d that are inclined relative to the cutting edge 73a. The inner inclined surface 74c and the outer inclined surface 74d are connected by a second groove bottom 74e having a substantially arc-shaped curved surface.

[0111] like Figure 13 As shown, an inner groove end 74a having a roughly arc-shaped rounded chamfer is provided at the intersection of the cutting edge 73a and the inner inclined surface 74c. An outer groove end 74b having a roughly arc-shaped rounded chamfer is provided at the intersection of the cutting edge 73a and the outer inclined surface 74d. The inner groove end angle between the inner inclined surface 74c and the cutting edge 73a is the same as the inner groove end angle 72f, which is 65°. The outer groove end angle between the outer inclined surface 74d and the cutting edge 73a is the same as the outer groove end angle 72g, which is 65°. The inter-groove end distance 16 between the inner groove end 72a and the inner groove end 74a is, for example, 0.04 mm. The first distance 75a between the first groove bottom 72e and the thickness center 7c is the same as the second distance 75b between the second groove bottom 74e and the thickness center 7c. The groove bottom distance 75 which is the sum of the first distance 75a and the second distance 75b is 0.35 mm or less, for example, 0.30 mm.

[0112] Then, based on Figure 14 The eighth embodiment of the present disclosure is described. The circular saw blade 80 has a first blade head 81 and a second blade head 83, which replace Figure 7 The first cutting head 11 and the second cutting head 13 are shown. The first cutting head 81 has a first groove 82 extending from the cutting edge 81a in the circumferential direction to replace Figure 7 The second cutting head 83 has a second groove 84 extending circumferentially from the cutting edge 83a, replacing the first groove 12. Figure 7 The second slot 14 is shown.

[0113] like Figure 14As shown, the first groove 82 is provided in the first thickness direction to the left of the thickness center 7c. When viewed from the front in the direction of rotation of the circular saw blade 80, the first groove 82 has a bilaterally symmetrical trapezoidal shape, such as an isosceles trapezoidal shape. The first groove 82 includes a generally planar inner inclined surface 82c and an outer inclined surface 82d that are inclined relative to the cutting edge 81a. The inner inclined surface 82c and the outer inclined surface 82d are connected by a generally planar first groove bottom 82e that extends generally parallel to the cutting edge 81a. The inner inclined surface 82c is connected to the first groove bottom 82e at the right end of the first groove bottom 82e, namely, the inner groove bottom end 82f. The outer inclined surface 82d is connected to the first groove bottom 82e at the left end of the first groove bottom 82e, namely, the outer groove bottom end 82g. The groove bottom width 82k between the inner groove bottom end 82f and the outer groove bottom end 82g is, for example, 0.10 mm.

[0114] like Figure 14 As shown, an inner groove end 82a is provided at the intersection of the cutting edge 81a and the inner inclined surface 82c. An outer groove end 82b is provided at the intersection of the cutting edge 81a and the outer inclined surface 82d. At the inner groove end 82a, an inner groove end angle 82h is defined between the inner inclined surface 82c and the cutting edge 81a. At the outer groove end 82b, an outer groove end angle 82i is defined between the outer inclined surface 82d and the cutting edge 81a. The inner groove end angle 82h and the outer groove end angle 82i are the same, at 65°. The groove bottom angle 82j between the inner inclined surface 82c and the outer inclined surface 82d is 50°.

[0115] like Figure 14 As shown, the second groove 84 is symmetrically shaped with the first groove 82 relative to the thickness center 7c and is located at a position symmetrical to the first groove 82. The second groove 84 is located in the second thickness direction to the right of the thickness center 7c. The second groove 84 has a substantially planar inner inclined surface 84c and an outer inclined surface 84d that are inclined relative to the cutting edge 83a. The inner inclined surface 84c and the outer inclined surface 84d are connected to the second groove bottom 84e at the inner groove bottom end 84f and the outer groove bottom end 84g, respectively. The second groove bottom 84e extends substantially parallel to the cutting edge 83a.

[0116] like Figure 14As shown, an inner groove end 84a is provided at the intersection of the cutting edge 83a and the inner inclined surface 84c. An outer groove end 84b is provided at the intersection of the cutting edge 83a and the outer inclined surface 84d. The inner groove end angle between the inner inclined surface 84c and the cutting edge 83a is the same as the inner groove end angle 82h, which is 65°. The outer groove end angle between the outer inclined surface 84d and the cutting edge 83a is the same as the outer groove end angle 82i, which is 65°. The inter-groove end distance 16 between the inner groove end 82a and the inner groove end 84a is, for example, 0.04 mm. The first distance 85a between the center of the first groove bottom 82e and the thickness center 7c is the same as the second distance 85b between the center of the second groove bottom 84e and the thickness center 7c. The inter-groove bottom distance 85, which is the sum of the first distance 85a and the second distance 85b, is less than 0.35 mm, for example, 0.30 mm.

[0117] Then, based on Figure 15 , illustrating a ninth embodiment of the present disclosure. The circular saw blade 90 has a first cutter head 91 and a second cutter head 93, which replace Figure 7 The first cutting head 11 and the second cutting head 13 are shown. The first cutting head 91 has a first groove 92 extending from the cutting edge 91a in the circumferential direction to replace Figure 7 The second cutting head 93 has a second groove 94 extending circumferentially from the cutting edge 93a, replacing the first groove 12. Figure 7 The second slot 14 is shown.

[0118] like Figure 15 As shown, the first groove 92 is provided in the first thickness direction to the left of the thickness center 7c. When viewed from the front in the rotational direction of the circular saw blade 90, the first groove 92 is generally V-shaped. The first groove 92 includes a generally planar inner inclined surface 92c and an outer inclined surface 92d, which are inclined relative to the cutting edge 91a. When viewed from the front in the rotational direction of the circular saw blade 90, the inner inclined surface 92c and the outer inclined surface 92d are connected by a first groove bottom 92e having an arc-shaped curved surface.

[0119] like Figure 15 As shown, an inner groove end 92a is provided at the intersection of the cutting edge 91a and the inner inclined surface 92c. An outer groove end 92b is provided at the intersection of the cutting edge 91a and the outer inclined surface 92d. An inner groove end angle 92f is defined between the inner inclined surface 92c and the cutting edge 91a. An outer groove end angle 92g is defined between the outer inclined surface 92d and the cutting edge 91a. The inner groove end angle 92f is greater than the outer groove end angle 92g and is less than 85°. The inner groove end angle 92f is, for example, 75°. The outer groove end angle 92g is, for example, 55°. The groove bottom angle 92h between the inner inclined surface 92c and the outer inclined surface 92d is 50°.

[0120] like Figure 15 As shown, the second groove 94 is symmetrically shaped with respect to the first groove 92 relative to the thickness center 7c and is located at a position symmetrical to the first groove 92. The second groove 94 is located in the second thickness direction to the right of the thickness center 7c. The second groove 94 has a substantially planar inner inclined surface 94c and an outer inclined surface 94d that are inclined relative to the cutting edge 93a. The inner inclined surface 94c and the outer inclined surface 94d are connected by a second groove bottom 94e. An inner groove end 94a is provided at the intersection of the cutting edge 93a and the inner inclined surface 94c. An outer groove end 94b is provided at the intersection of the cutting edge 93a and the outer inclined surface 94d. The inner groove end angle between the inner inclined surface 94c and the cutting edge 93a is the same as the inner groove end angle 92f, for example, 75°. The outer groove end angle between the outer inclined surface 94d and the cutting edge 93a is the same as the outer groove end angle 92g, for example, 55°.

[0121] like Figure 15 As shown, the distance 16 between the inner groove end 92a and the inner groove end 94a is, for example, 0.04 mm. The first distance 95a between the first groove bottom 92e and the thickness center 7c is the same as the second distance 95b between the second groove bottom 94e and the thickness center 7c. The first distance 95a and the second distance 95b are the same as the distance between the first groove bottom 92e and the second groove bottom 94e, which is closest to the substrate 2 (see FIG. Figure 5 The sum of the first distance 95a and the second distance 95b is less than 0.35mm and is greater than Figure 7 The distance 15 between the groove bottoms shown is small. The distance 95 between the groove bottoms is, for example, 0.22 mm.

[0122] Then, based on Figure 16 The tenth embodiment of the present disclosure is described. The circular saw blade 100 has a first blade head 101 and a second blade head 103, which replace Figure 7 The first cutting head 11 and the second cutting head 13 are shown. The first cutting head 101 has a first groove 102 extending from the cutting edge 101a in the circumferential direction to replace Figure 7 The second cutting head 103 has a second groove 104 extending circumferentially from the cutting edge 103a, replacing the first groove 12. Figure 7 The second slot 14 is shown.

[0123] like Figure 16As shown, the first groove 102 is provided in the first thickness direction to the left of the thickness center 7c. When viewed from the front in the rotational direction of the circular saw blade 100, the first groove 102 is generally V-shaped. The first groove 102 includes a generally planar inner inclined surface 102c and an outer inclined surface 102d, which are inclined relative to the cutting edge 101a. When viewed from the front in the rotational direction of the circular saw blade 100, the inner inclined surface 102c and the outer inclined surface 102d are connected by a first groove bottom 102e having an arc-shaped curved surface.

[0124] like Figure 16 As shown, an inner groove end 102a is provided at the intersection of the cutting edge 101a and the inner inclined surface 102c. An outer groove end 102b is provided at the intersection of the cutting edge 101a and the outer inclined surface 102d. An inner groove end angle 102f is defined between the inner inclined surface 102c and the cutting edge 101a. An outer groove end angle 102g is defined between the outer inclined surface 102d and the cutting edge 101a. The outer groove end angle 102g is greater than the inner groove end angle 102f and is less than 85°. The inner groove end angle 102f is, for example, 55°. The outer groove end angle 102g is, for example, 75°. The groove bottom angle 102h between the inner inclined surface 102c and the outer inclined surface 102d is 50°.

[0125] like Figure 16 As shown, the second groove 104 is symmetrical with the first groove 102 relative to the thickness center 7c and is arranged at a position symmetrical with the first groove 102. The second groove 104 is arranged in the second thickness direction to the right of the thickness center 7c. The second groove 104 has a substantially planar inner inclined surface 104c and an outer inclined surface 104d that are inclined relative to the cutting edge 103a. The inner inclined surface 104c and the outer inclined surface 104d are connected by a second groove bottom 104e. The inner groove end 104a is provided at the intersection of the cutting edge 103a and the inner inclined surface 104c. The outer groove end 104b is provided at the intersection of the cutting edge 103a and the outer inclined surface 104d. The inner groove end angle between the inner inclined surface 104c and the cutting edge 103a is the same as the inner groove end angle 102f, for example, 55°. The outer groove end angle between the outer inclined surface 104d and the cutting edge 103a is the same as the outer groove end angle 102g, for example, 75 degrees.

[0126] like Figure 16 As shown, the distance 16 between the inner groove end 102a and the inner groove end 104a is, for example, 0.04 mm. The first distance 105a between the first groove bottom 102e and the thickness center 7c is the same as the second distance 105b between the second groove bottom 104e and the thickness center 7c. The distance 105 between the groove bottoms, which is the sum of the first distance 105a and the second distance 105b, is 0.35 mm or less and greater than Figure 7The distance between groove bottoms is 15 mm. The distance between groove bottoms 105 is, for example, 0.35 mm. A relatively large distance between groove bottoms 105 allows the inner groove ends 102a and 104a to be formed at a relatively large obtuse angle. Consequently, chipping at the inner groove ends 102a and 104a can be suppressed.

[0127] like Figure 17 、 18 As shown, a comparative experiment on the relationship between the groove shape and the lateral displacement of the circular saw blades of the above-mentioned embodiments was conducted. The test products were all circular saw blades with an outer diameter of 285mm, a blade thickness of 1.0mm, a base thickness of 0.8mm, a mounting hole diameter of 40mm, and 80 blades. The cutter head used a hard cutter head made of metal ceramic. The cut material used was a non-tempered steel rod with an outer diameter of 37mm. Cutting was carried out under the cutting conditions of a rotation number of 150rpm, a cutting depth of 0.105mm for each blade, and a feed speed of 1260mm / min. The feed speed is approximately 2.5 times that of general cutting processing. The test product 70V is equivalent to Figure 9 The circular saw blade 30 shown. The test product 60V is Figure 7 The inner groove end angle 12f and the outer groove end angle 12g of the circular saw blade 1 shown are replaced with 60 degrees, and the groove bottom angle 12h is replaced with a circular saw blade of 60 degrees. Figure 7 The circular saw blade shown is 1. The test product 30V is equivalent to Figure 8 The circular saw blade 20 shown. The test piece 0.2U is Figure 10 The slot width 42h of the circular saw blade 40 shown is replaced with a circular saw blade having a slot width of 0.20.

[0128] like Figure 17 、 18 As shown, the larger the groove end angle, the smaller the distance between the groove bottoms can be set. Furthermore, it can be seen that the smaller the distance between the groove bottoms, the smaller the lateral displacement of the tool head can be suppressed. In particular, between the test piece 60V with a groove end angle of 60° and the test piece 50V with a groove end angle of 65°, the lateral displacement was suppressed to above 0.001mm. Furthermore, the lateral displacement of the test piece 0.2U with a groove end angle of 90° was suppressed to less than half that of the test piece 70V with a groove end angle of 55°.

[0129] like Figures 19-24 As shown in FIG, for each embodiment of the tool head, the equivalent stress simulation during cutting was performed. The test piece and cutting conditions were set to the same Figure 17 、 18 The test is the same as shown. When the tool tip cuts the workpiece, the equivalent stress applied to the tool tip at a cross section at a depth d of 0.10 mm from the bottom surface of a groove formed in the workpiece is simulated.

[0130] The simulation results are as follows Figures 20-24 As shown, it can be seen that high equivalent stress is generated near the cutting edge on both sides of each cutting head. If the cutting edge with a smaller width on the left side of the figure is compared with the cutting edge with a larger width on the right side of the figure, the maximum values ​​of the equivalent stress are roughly the same. Regarding the distribution of equivalent stress, the high value of the equivalent stress of the cutting edge with a smaller width is more widely distributed than that of the cutting edge with a larger width on the right side of the figure. Moreover, there is a tendency that the larger the groove end angle of the groove formed in the cutting head, the more widely the high equivalent stress distribution is distributed from the side of the cutting head to the groove. In particular, in the case of the test piece 30V with a groove end angle of 75° and the test piece 0.2U with a groove end angle of 90°, Figure 8 The outer inclined surface 22d and Figure 10 The position corresponding to the outer rising surface 42e shown generates an equivalent stress of substantially the same magnitude as that of the left side 11d. When a test was conducted in which the workpiece was cut at 0.2U using the test piece, a chip was generated at the position corresponding to the outer rising surface 42e.

[0131] Based on the above test and simulation results, a cutter head with slots with an end angle of 60° to 85° is selected as a preferred structure for this disclosure. This structure can suppress lateral displacement of the cutter head and reduce the generation of large equivalent stresses around the slot ends. This improves the durability of the cutter head.

[0132] like Figure 25 As shown in FIG, the number of thermal cracks generated in the circular saw blades 1 and 30 was measured. The test pieces and cutting conditions were set to the same Figure 17 、 18 The same test as shown. Cutting was carried out until the number of cuts was equivalent to 18,000 cuts, and the number of blades that had thermal cracks was measured for each state of thermal cracks. Figure 25 θ1 represents the inner groove end angles 12f and 32f (see Figure 7 、 9 ), θ2 represents the outer groove end angle 12g, 32g. The cutting edges 11c, 31a on the side with the longer blade tip length represent the area from the inner groove ends 12a, 32a to the intersection with the right chamfer 11f. The cutting edges 11c, 31a on the side with the shorter blade tip length represent the area from the outer groove ends 12b, 32b to the intersection with the left chamfer 11f.

[0133] like Figure 25 As shown in FIG. 1 , no thermal cracks are generated on the cutting edge 11c on the side of the circular saw blade 1 where the blade tip length is smaller. Figure 25In the figure, the blade with brackets shows a blade with a defect starting from a portion that is not a boundary wear area caused by friction with the cut material. No other defects were found in this blade. Therefore, it is considered that the defect is not caused by thermal cracks and is excluded from the number of thermal cracks. Figure 7 ) in the cutting edge 11c on the side with the longer blade tip (see Figure 7 ) Small thermal cracks with 1 to 2 lines occurred on the cutting edge 11c. Large thermal cracks with 3 or more lines and defects caused by thermal cracks did not occur on the cutting edge 11c on the side with a longer blade tip.

[0134] like Figure 25 As shown, the 13 blade heads 7 (refer to Figure 9 ), 13 of the cutter heads 7 had minor thermal cracks on the cutting edge 31a on the side with the shorter blade tip length. No major thermal cracks or defects due to thermal cracks occurred on the cutting edge 31a on the side with the shorter blade tip length. All of the cutter heads 7 for the circular saw blade 30 had thermal cracks on the cutting edge 31a on the side with the longer blade tip length. Major thermal cracks occurred in 65 of the cutter heads 7, and defects due to thermal cracks occurred in 3 of the cutter heads 7.

[0135] like Figures 26-37 As shown, the state of the notch of the blade head 7 generated during cutting is compared for the circular saw blades 1 and 30. The test pieces and cutting conditions are set to the same Figure 17 、 18 The experiments shown are identical. Figures 27-30 The first circular saw blade 1 shown and Figure 36 、 37 The circular saw blade 30 shown cuts until the number of cuts corresponds to 20,000 cuts. Figure 31 、 32 The second circular saw blade 1 shown has four blades and performs cutting until the number of cuts is equivalent to 20,000 cuts. Figures 33-35 The third circular saw blade 1 shown has the number of blades set to 4 and is cut until the number of cuts is equivalent to 25,000 cuts.

[0136] like Figure 26 、 30 As shown in FIG. 1 , a large defect is generated on the left side of a cutter head 7 of the first circular saw blade 1, starting from the vicinity of the first groove bottom. As described above, this defect is a defect starting from a portion of the boundary wear area that is not caused by friction with the cut material. Therefore, it is not considered to be a defect caused by thermal cracking. Due to this defect, streaks are generated on the cut surface of the cut material. Figures 26-29As shown, no thermal cracks occurred on the right side surface 13e connected to the narrow cutting edge 13c, while small thermal cracks with one or two lines occurred on the left side surface 13d connected to the wide cutting edge 13c.

[0137] like Figure 26 、 31 As shown in Figures 32 and 33, no thermal cracks occurred on the right side surface 13e connected to the narrower cutting edge 13c of the second circular saw blade 1. Small thermal cracks, consisting of one or two lines, occurred on the left side surface 13d connected to the wider cutting edge 13c. The cut surface of the workpiece was good.

[0138] like Figure 26 、 33 As shown in Figures 35 to 36, in the blade head 7 of the third circular saw blade 1, no thermal cracks occurred on the right side 13e connected to the cutting edge 13c on the narrower side. Small thermal cracks, consisting of one to two lines, occurred on the left side 13d connected to the cutting edge 13c on the wider side. Cracks developed from the left side 13d where the thermal cracks occurred toward the right. The cut surface of the cut material was good. As described above, in the blade head 7 of the circular saw blade 1, cracks occurred near the second groove 14 before cracks occurred on the left side 13d and the right side 13e.

[0139] like Figure 36 、 37 As shown, in the cutter head 7 of the circular saw blade 30, large thermal cracks with three or more lines and defects caused by the thermal cracks occurred on the left side 13d connected to the cutting edge 33a on the wider side. On the right side 13e connected to the cutting edge 13c on the narrower side, the occurrence of thermal cracks was suppressed.

[0140] Based on the above test results, a preferred structure disclosed herein includes a first cutting head and a second cutting head, wherein the sum of the first distance from the bottom of the first groove to the center of the thickness of the cutting edge and the second distance from the bottom of the second groove to the center of the thickness of the cutting edge is less than 0.35 mm, and particularly less than 0.28 mm. This structure can suppress thermal cracks that may occur on the side of the cutting head. In particular, it is possible to effectively suppress the occurrence of thermal cracks on the side connected to the cutting edge on the wider side. It is also possible to suppress thermal cracks on the side connected to the cutting edge on the narrower side in a manner that does not affect the cut surface of the cut material.

[0141] Various modifications can be made to the circular saw blades of the various embodiments described above. A structure in which the first and second cutting heads 11 and 13 are mounted on the base 2 so that the thickness centers 7c of the first and second cutting heads 11 and 13 coincide with the thickness center 2b of the base 2 is illustrated as an example. For example, a structure in which the thickness center 7c of the first cutting head 11 is arranged to the right of the thickness center 2b of the base 2 and the thickness center 7c of the second cutting head 13 is arranged to the left of the thickness center 2b of the base 2 can be substituted for the above structure. An example structure in which the first groove 12 and the second groove 14 do not overlap each other when viewed from the front in the rotation direction of the circular saw blade 1 is illustrated as an example. Alternatively, a structure in which the first and second grooves 12 and 14 overlap each other when viewed from the front in the rotation direction of the circular saw blade 1 can be substituted for the above structure. Alternatively, a structure in which a portion of the first groove 12 or the second groove 14 spans the thickness center 2b of the base 2 can be substituted.

[0142] The example shows the first groove 12 and the second groove 14 having a bilaterally symmetrical shape and being arranged at bilaterally symmetrical positions relative to the thickness center 7c of the tool head 7. Instead of the above structure, the first groove 12 and the second groove 14 may be arranged in a bilaterally asymmetrical shape relative to the thickness center 7c of the tool head 7. Alternatively, the first groove 12 and the second groove 14 may be arranged at bilaterally asymmetrical positions relative to the thickness center 7c.

[0143] The thickness 7d of the blade tip 7 is not limited to the 0.8 to 1.1 mm shown in the example, but may also be, for example, 1.1 to 2.0 mm. The groove end angle is not limited to the angle shown in the example, but may also be, for example, 70°, 80°, or 85°. The groove end angle of a pair of groove ends may both fall within the range of 60° to 85°, or one may fall within the range of 60° to 85°. The distance 16 between groove ends may be greater or less than the 0.04 mm shown in the example.

[0144] For example, the first groove 52 can be set so that the size of the inner groove end angle 52j is different from the size of the outer groove end angle 52k. For example, R chamfers can be set at the inner U-shaped end 52d and the outer U-shaped end 52g. For example, the first groove 62 can be set so that the groove end angles at the inner groove end 62a and the outer groove end 62b are 60° to 85°. For example, the groove bottom angles 92h and 102h can be set to be greater than or less than the 50° shown in the example. The groove extends in the circumferential direction, but can also be slightly inclined at an angle below the rear angle. In addition, the groove width can be expanded toward the rear in the rotation direction.

Claims

1. A circular saw blade with a cutter head, wherein: have: A disc-shaped substrate with an outer diameter of 200 mm to 500 mm, and The first cutting head and the second cutting head protrude radially from the outer circumference of the base body and are alternately arranged along the outer circumference of the base body; The circular saw blade has a blade thickness of 0.8 mm to 2.0 mm. The first cutting head and the second cutting head have: The rake face faces forward in the direction of rotation of the circular saw blade. a flank surface, facing radially outward of the base body, a cutting edge formed between the rake face and the flank face, a pair of chamfers provided at both ends of the cutting edge, and a groove formed on the flank surface so as to extend circumferentially from the cutting edge; The groove of the first cutting head has a first groove bottom, and the first groove bottom is radially deepest at a position at a first distance from the thickness center of the cutting edge of the first cutting head in the first thickness direction. The groove of the second cutting head has a second groove bottom, and the second groove bottom is radially deepest at a position a second distance away from the thickness center of the cutting edge of the second cutting head in a second thickness direction opposite to the first thickness direction, and the sum of the first distance and the second distance is less than 0.35 mm.

2. The circular saw blade with a cutter head according to claim 1, wherein: The tank has: a pair of groove ends intersecting the cutting edge, and a pair of inclined surfaces, provided between either one of the pair of groove ends and the groove bottom and inclined relative to the cutting edge; At the groove end, the groove end angle between the cutting edge and the inclined surface is 60° to 85°.

3. The circular saw blade with a cutter head according to claim 1 or 2, wherein: The tank has: a pair of groove ends intersecting the cutting edge, and a pair of inclined surfaces, provided between either one of the pair of groove ends and the groove bottom and inclined relative to the cutting edge; At the groove end, the groove end angle between the cutting edge and the inclined surface is greater than the angle of the pair of chamfers relative to the cutting edge.

4. The circular saw blade with a cutter head according to any one of claims 1 to 3, wherein: The sum of the first inner distance and the second inner distance is smaller than the opening width of the first groove in the cutting edge and smaller than the opening width of the second groove in the cutting edge, the first inner distance is the distance between the inner end edge of the first groove as the groove of the first cutting head and the thickness center of the cutting edge of the first cutting head, and the second inner distance is the distance between the inner end edge of the second groove as the groove of the second cutting head and the thickness center of the cutting edge of the second cutting head.

5. The circular saw blade with a cutter head according to claim 4, wherein: The sum of the first inner distance and the second inner distance is less than half of an opening width of the first groove in the cutting edge and less than half of an opening width of the second groove in the cutting edge.

6. The circular saw blade with a cutter head according to any one of claims 1 to 5, wherein: A first radial depth of the groove of the first cutting head from the cutting edge and a second radial depth of the groove of the second cutting head from the cutting edge are both greater than 2 times and less than 5 times the radial depth of the pair of chamfers from the cutting edge.

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