CIRCULAR SAW BLADE

Abstract

In a circular saw blade, cutting teeth are joined to tooth bodies projecting outward in a radial direction at locations on an outer periphery of a disk-shaped metal base, gullets are provided between the tooth bodies so as to be recessed in the radial direction, radial clearance angles of side cutting edges of the cutting teeth are greater than 1 and less than 1, and a vibration prevention mechanism for preventing vibration of the metal base itself is provided. A ratio of a difference between a maximum value and a minimum value of pitches of the multiple cutting teeth to an average value of the pitches is 40% to 100%. A ratio of a difference between a maximum value and a minimum value of average values of depths of the adjacent gullets to an average value of depths of the gullets may be 20% to 100%.

Claims

1. A circular saw blade in which cutting teeth are joined to a plurality of tooth bodies projecting outward in a radial direction at a plurality of locations on an outer periphery of a disk-shaped metal base, gullets are provided between the plurality of tooth bodies so as to be recessed in the radial direction, radial clearance angles of side cutting edges of the cutting teeth are greater than 1 and less than 1, and a vibration prevention mechanism for preventing vibration of the metal base itself is provided, wherein pitches of the multiple cutting teeth are at least partially different, and a ratio of a difference between a maximum value and a minimum value of the pitches to an average value of the pitches is 40% to 100%.

2. A circular saw blade in which cutting teeth are joined to a plurality of tooth bodies projecting outward in a radial direction at a plurality of locations on an outer periphery of a disk-shaped metal base, gullets are provided between the plurality of tooth bodies so as to be recessed in the radial direction, radial clearance angles of side cutting edges of the cutting teeth are greater than 1 and less than 1, and a vibration prevention mechanism for preventing vibration of the metal base itself is provided, wherein depths of the multiple gullets are at least partially different, and a ratio of a difference between a maximum value and a minimum value of average values of depths of the adjacent gullets to an average value of the depths of the gullets is 20% to 100%.

3. A circular saw blade in which cutting teeth are joined to a plurality of tooth bodies projecting outward in a radial direction at a plurality of locations on an outer periphery of a disk-shaped metal base, gullets are provided between the plurality of tooth bodies so as to be recessed in the radial direction, radial clearance angles of side cutting edges of the cutting teeth are greater than 1 and less than 1, and a vibration prevention mechanism for preventing vibration of the metal base itself is provided, wherein pitches of the multiple cutting teeth are at least partially different, depths of the multiple gullets are at least partially different, a ratio of a difference between a maximum value and a minimum value of the pitches to an average value of the pitches is 20% to 100%, and a ratio of a difference between a maximum value and a minimum value of average values of depths of the adjacent gullets to an average value of the depths of the gullets is 10% to 100%.

4. The circular saw blade according to claim 1, wherein a bending point is provided at an intermediate point of each side cutting edge of the cutting teeth, a radial clearance angle at an outer peripheral side from the bending point is greater than 1 and less than 0, and a radial clearance angle at a center side from the bending point is greater than 0 and less than 1.

5. The circular saw blade according to claim 2, wherein a bending point is provided at an intermediate point of each side cutting edge of the cutting teeth, a radial clearance angle at an outer peripheral side from the bending point is greater than 1 and less than 0, and a radial clearance angle at a center side from the bending point is greater than 0 and less than 1.

6. The circular saw blade according to claim 3, wherein a bending point is provided at an intermediate point of each side cutting edge of the cutting teeth, a radial clearance angle at an outer peripheral side from the bending point is greater than 1 and less than 0, and a radial clearance angle at a center side from the bending point is greater than 0 and less than 1.

Description

BRIEF DESCRIPTION OF DRAWINGS

[0024] FIG. 1 is an overall view for explaining Case 1 of a circular saw blade according to claim 1 of the present invention;

[0025] FIG. 2 is a partially enlarged view showing a part of the circular saw blade of Case 1 in an enlarged manner;

[0026] FIG. 3 is a partially enlarged view showing a part of a circular saw blade of Case 2 in an enlarged manner;

[0027] FIG. 4 is a partially enlarged view showing a part of a circular saw blade of Case 3 in an enlarged manner;

[0028] FIG. 5 is a partially enlarged view showing a part of a circular saw blade in an enlarged manner for explaining Case 4 of a circular saw blade according to claim 2 of the present invention;

[0029] FIG. 6 is a partially enlarged view showing a part of a circular saw blade in an enlarged manner for explaining Case 5 of a circular saw blade according to claims 1 and 2 of the present invention;

[0030] FIG. 7 is a partially enlarged view showing a part of a circular saw blade in an enlarged manner for explaining Case 6 of a circular saw blade according to claim 3 of the present invention;

[0031] FIG. 8 is an overall view showing a circular saw blade according to Embodiment 1;

[0032] FIG. 9A is an enlarged front view showing a cutting tooth fixed to a tooth body in an enlarged manner;

[0033] FIG. 9B is an enlarged side view showing the cutting tooth fixed to the tooth body in an enlarged manner;

[0034] FIG. 10 is an overall view showing a circular saw blade according to Embodiment 2; and

[0035] FIG. 11 is an overall view showing a circular saw blade according to Embodiment 3.

DESCRIPTION OF EMBODIMENTS

[0036] Hereinafter, embodiments of the present invention are described with reference to the drawings. FIG. 8 shows an overall view of a circular saw blade 20 according to Embodiment 1. A metal base 21 forming a part of the circular saw blade 20 is a disk-shaped thin plate made of steel and having an outer diameter of 305 mm and a tooth thickness of 2.8 mm, and a central hole 22 into which a rotary shaft of machining equipment is inserted is provided at the center of the metal base 21. At the outer peripheral side of the metal base 21, tooth bodies 23 having a substantially rhombic shape are provided at 72 locations in the circumferential direction so as to project in the radial direction, and gullets 24 are provided so as to be recessed in the radial direction by cutting portions between the respective tooth bodies 23 into an arc shape. A mounting seat 25 for mounting a cutting tooth 28 is provided at a front end side, in a rotation direction R, of each tooth body 23 by cutting the tooth body 23 substantially at a right angle.

[0037] Regarding the respective tooth bodies 23, adjacent three tooth bodies 23a, 23b, and 23c are defined as one set, and 24 sets are provided in total. The pitches of the cutting teeth 28 in each set are set to 4, and the pitch between each set is set to 7. The depths of gullets 24a, 24b, and 24c between the tooth bodies 23a, 23b, and 23c of one set are set to 7.9 mm, 7.9 mm, and 9.8 mm, respectively. At the outer peripheral side of the metal base 21, six wavy outer slots 26 are provided at six locations, that is, each provided every four sets of the tooth bodies 23, so as to extend toward the center. In addition, six inner slots 27 are provided between the respective outer slots 26 so as to extend in a wavy manner toward the center from positions away from the outer periphery. These slots 26 and 27 are filled with a resin, and thus serve as a vibration prevention mechanism for inhibiting vibration due to the metal base 21 of the circular saw blade 20.

[0038] The cutting teeth 28 are welded to the mounting seats 25 by means of brazing or the like. Each cutting tooth 28 is obtained by processing using a hard material such as cemented carbide, has an elongated substantially rectangular parallelepiped shape as shown in FIG. 9A and FIG. 9B, and is formed in a shape that allows the cutting tooth 28 to be substantially in close contact with the mounting seat 25. The cutting tooth 28 has a front face (rake face) 28r slanted at a rake angle , a back face 28s substantially parallel to the front face 28r, an upper face (flank face) 28t that is an slanted surface slanted at a top clearance angle , and a bottom face 28u substantially perpendicular to the front face 28r. A front end cutting edge 28v is formed between the upper face 28t and the rake face 28r. Side cutting edges 28w at both side faces 28x in the width direction of the cutting tooth 28 each have a radial clearance angle that satisfies 1<10 or is 0 or negative, in the area from the upper face 28t to a bending point K at the intermediate point, and each have a positive radial clearance angle that satisfies 0<2<1, in the area from the bending point K to the bottom face 28u.

[0039] In Embodiment 1, the pitches of three cutting teeth 28a, 28b, and 28c are 4, 4, and 7, respectively, so that the sum of the pitches is 15, the average value of the pitches is 15/3=5, and the difference between the maximum value and the minimum value of the pitches is 74=3. The ratio of the difference between the maximum value and the minimum value of the pitches to the average value of the pitches is 3/5100=60%. In addition, the depths of the gullets 24a, 24b, and 24c between the three tooth bodies 23a, 23b, and 23c are 7.9 mm, 7.9 mm, and 9.8 mm, respectively, so that the sum of the depths of the gullets 24a, 24b, and 24c is 25.6 mm and the average value of the depths is 8.533 mm. The average values of the depths of the adjacent gullets 24a, 24b, and 24c are 7.9 mm, 8.85 mm, and 8.85 mm, the maximum value thereof is 8.85 mm, and the minimum value thereof is 7.9 mm. As a result, the ratio of the difference between the maximum value and the minimum value of the average values of the depths of the adjacent gullets to the average value of the depths of the gullets 24a, 24b, and 24c is (8.85 mm7.9 mm)/8.533 mm100=11.1%.

[0040] As described above, the pitches of the cutting teeth 28 and the depths of the gullets 24 satisfy the above conditions I and III, the intermittent vibration frequency between the cutting teeth 28 and the natural vibration frequency of each tooth portion are variable, and thus cutting vibration due to the cutting teeth 28 is inhibited. As a result, regarding the circular saw blade 20 according to the Embodiment 1, cutting vibration due to the cutting teeth themselves is inhibited by making the intermittent vibration frequency between the cutting teeth 28 and the natural vibration frequency of each tooth portion different, and cutting vibration of the circular saw blade 20 is assuredly inhibited in combination with the vibration prevention mechanism that prevents vibration of the metal base 21. As a result, in Embodiment 1, with the circular saw blade 20 in which the radial clearance angles of the side cutting edges of the cutting teeth 28 are greater than 1 and less than 1, the surface roughness of a finished surface of a work material is decreased while cutting vibration is inhibited. Particularly, when the radial clearance angle 1 at the outer peripheral side is greater than 1 and less than 0 and the radial clearance angle 2 at the center side from the bending point K is greater than 0 and less than 1 in order to improve the finish of a cut section, cutting resistance increases and a load on the cutting tooth portions and the like increases, but the effect of inhibiting cutting vibration is further exerted.

[0041] Next, Embodiment 2 is described with reference to FIG. 10.

[0042] FIG. 10 shows an overall view of a circular saw blade 30 according to Embodiment 2. A metal base 31 forming a part of the circular saw blade 30 is a disk-shaped thin plate made of steel and having an outer diameter of 305 mm and a tooth thickness of 2.0 mm, and a central hole 32 into which a rotary shaft of machining equipment is inserted is provided at the center of the metal base 31. At the outer peripheral side of the metal base 31, tooth bodies 33 are provided at 49 locations in the circumferential direction so as to project in the radial direction in a substantially rhombic shape, and gullets 34 are provided so as to be recessed in the radial direction by cutting portions between the tooth bodies 33 into an arc shape. A mounting seat 35 for mounting a cutting tooth 38 that is similar to the above cutting tooth 28 is provided at a front end side, in a rotation direction R, of each tooth body 33 by cutting the tooth body 33 substantially at a right angle. The cutting tooth 38 that is similar to the above cutting tooth 28 is fixed to the mounting seat 35 by means of brazing or the like.

[0043] Regarding the respective tooth bodies 33, adjacent seven tooth bodies 33a to 33g are defined as one set, and seven sets are provided in total. The pitches of cutting teeth 38a to 38g in each set are set to 5.86, 7.35, 8.82, 6.86, 8.33, 6.37, and 7.84, respectively. The depths of gullets 34a to 34g between the tooth bodies 33a to 33g of one set are set to 8.2 mm, 8.5 mm, 8.8 mm, 9.0 mm, 9.3 mm, 9.6 mm, and 9.8 mm, respectively. At the outer peripheral side of the metal base 31, five outer slots 36 are provided at five locations spaced at equal intervals in the circumferential direction so as to extend toward the center, and five inner slots 37 are provided between the respective outer slots 36 so as to extend in a wavy manner toward the center from positions away from the outer periphery. The inner slots 37 are filled with a resin, and the slots 36 and 37 serve as a vibration prevention mechanism for inhibiting cutting vibration due to the metal base 31.

[0044] In Embodiment 2, the sum of the pitches of the seven cutting teeth 38a to 38g is 51.43, the average value of the pitches is 51.43/7=7.35, and the difference between the maximum value and the minimum value of the pitches is 8.825.86=2.96. The ratio of the difference between the maximum value and the minimum value of the pitches to the average value of the pitches is 2.96/7.35100=40.3%. In addition, the sum of the depths of the gullets 34a to 34g between the seven cutting teeth 38a to 38g is 63.2 mm, and the average value of the depths is 63.2/7=9.03 mm. The average values of the depths of the adjacent gullets 34a to 34g are 8.35 mm, 8.65 mm, 8.9 mm, 9.15 mm, 9.45 mm, 9.7 mm, and 9.0 mm, respectively, and the differences between the maximum value and the minimum value of the average values is 9.7 mm8.35 mm=1.35 mm. As a result, the ratio of the difference between the maximum value and the minimum value of the average values of the depths of the adjacent gullets 38 to the average value of the depths of the gullets 38 is 1.35 mm/9.03 mm100=15.0%.

[0045] As described above, the pitches of the cutting teeth 38 and the depths of the gullets 34 satisfy the above conditions I and III, the intermittent vibration frequency between the cutting teeth 38 and the natural vibration frequency of each tooth portion are variable, and thus cutting vibration due to the cutting teeth 38 is inhibited. As a result, regarding the circular saw blade 30 according to the Embodiment 2, cutting vibration due to the cutting teeth themselves is inhibited by making the intermittent vibration frequency between the cutting teeth 38 and the natural vibration frequency of each tooth portion different, and cutting vibration of the circular saw blade 30 is assuredly inhibited in combination with the vibration prevention mechanism that prevents vibration of the metal base 31. As a result, in Embodiment 2, with the circular saw blade 30 in which the radial clearance angles of the side cutting edges of the cutting teeth 38 are greater than 1 and less than 1, a satisfactory finished surface of a work material having small surface roughness is ensured while cutting vibration is inhibited. Particularly, when the radial clearance angle 1 at the outer peripheral side is greater than 1 and less than 0 and the radial clearance angle 2 at the center side from the bending point K is greater than 0 and less than 1 in order to improve the finish of a cut section, cutting resistance increases and a load on the tooth portions and the like increases, but the effect of inhibiting cutting vibration is further exerted.

[0046] Next, Embodiment 3 is described with reference to FIG. 11.

[0047] An overall view of a circular saw blade 40 according to Embodiment 3 is shown. A metal base 41 forming a part of the circular saw blade 40 is a disk-shaped thin plate made of steel and having an outer diameter of 305 mm and a tooth thickness of 2.0 mm, and a central hole 42 into which a rotary shaft of machining equipment is inserted is provided at the center of the metal base 41. At the outer peripheral side of the metal base 41, tooth bodies 43 are provided at 48 locations in the circumferential direction so as to project in the radial direction in a substantially rhombic shape, and gullets 44 are provided so as to be recessed in the radial direction by cutting portions between the tooth bodies 43 into an arc shape. A mounting seat 45 for mounting a cutting tooth 48 is provided at a front end side, in a rotation direction R, of each tooth body 43 by cutting the tooth body 43 substantially at a right angle. The cutting tooth 48 that is similar to the above cutting tooth 28 is fixed to the mounting seat 45 by means of brazing or the like.

[0048] Regarding the respective tooth bodies 43, adjacent four tooth bodies 43a to 43d are defined as one set, and 12 sets are provided in total. The pitches of cutting teeth 48a to 48d in each set are set to 6.5, 6.5, 8.5, and 8.5, respectively. The depths of gullets 44a to 44d between the tooth bodies 43a to 43d of one set are set to 8.6 mm, 8.6 mm, 9.7 mm, and 9.7 mm, respectively. At the outer peripheral side of the metal base 41, five outer slots 46 are provided at five locations spaced at equal intervals in the circumferential direction so as to extend toward the center, and five inner slots 47 are provided between the respective outer slots 46 so as to extend in a wavy manner toward the center from positions away from the outer periphery. The inner slots 47 are filled with a resin, and these slots 46 and 47 serve as a vibration prevention mechanism for inhibiting vibration of the circular saw blade 40 due to the metal base 41.

[0049] In Embodiment 3, the sum of the pitches of the four cutting teeth 48a to 48d is 30, the average value of the pitches is 30/4=7.5, and the difference between the maximum value and the minimum value of the pitches is 8.56.5=2. The ratio of the difference between the maximum value and the minimum value of the pitches to the average value of the pitches is 2/7.5100=26.7%. In addition, the sum of the depths of the four gullets 44a to 44d is 36.6 mm, and the average value of the depths is 36.6 mm/4=9.15 mm. The average values of the depths of the adjacent gullets are 8.6 mm, 9.15 mm, 9.7 mm, and 9.15 mm, respectively, and the difference between the maximum value and the minimum value of the average values is 9.7 mm8.6 mm=1.1 mm. As a result, the ratio of the difference between the maximum value and the minimum value of the average values of the depths of the adjacent gullets to the average value of the depths of the gullets is 1.1 mm/9.15 mm100=12.0%.

[0050] As described above, the pitches of the cutting teeth 48 and the depths of the gullets 44 satisfy the above condition III, the intermittent vibration frequency between the cutting teeth 48 and the natural vibration frequency of each tooth portion are variable, and thus cutting vibration due to the cutting teeth 48 is inhibited. As a result, regarding the circular saw blade 40 according to the Embodiment 3, cutting vibration due to the cutting teeth themselves is inhibited by making the intermittent vibration frequency between the cutting teeth 48 and the natural vibration frequency of each tooth portion different, and cutting vibration of the circular saw blade 40 is assuredly inhibited in combination with the vibration prevention mechanism that prevents vibration of the metal base 41. As a result, in Embodiment 3, with the circular saw blade 40 in which the radial clearance angles of the side cutting edges of the cutting teeth 48 are greater than 1 and less than 1, a satisfactory finished surface of a work material having small surface roughness is ensured while cutting vibration is inhibited. Particularly, when the radial clearance angle 1 at the outer peripheral side is greater than 1 and less than 0 and the radial clearance angle 2 at the center side from the bending point K is greater than 0 and less than 1 in order to improve the finish of a cut section, cutting resistance increases and a load on the tooth portions and the like increases, but the effect of inhibiting cutting vibration is further exerted.

[0051] Next, a specific cutting test example using circular saw blades is described.

[0052] A cutting test was conducted in which the circular saw blades of Cases 1 to 6 described above were used, 16 types of rotation speeds were set from 3000 rpm to 6000 rpm at intervals of 200 rpm as rotation speeds N of cutting, and Japanese hemlock was used as a work material. For comparison, a circular saw blade in which the ratio of the difference between the maximum value and the minimum value of the pitches to the average value of the pitches and the ratio of the difference between the maximum value and the minimum value of the average values of the depths of the adjacent gullets to the average value of the depths of the gullets are each 0%, was used as a conventional example. The results of cutting were evaluated through visual observation, indicates that the surface roughness of a finished surface (cut section) is very small and satisfactory, x indicates that the surface roughness of a finished surface is large and defective, and indicates that the surface roughness of a finished surface is satisfactory to some extent. The results of the cutting test are shown in Table 1 below. In Table 1, the ratio of the difference between the maximum value and the minimum value of the pitches to the average value of the pitches is represented as pitch difference ratio, and the ratio of the difference between the maximum value and the minimum value of the average values of the depths of the adjacent gullets to the average value of the depths of the gullets is represented as gullet depth difference ratio.

TABLE-US-00001 TABLE 1 Gullet Pitch depth difference difference ratio ratio Rotation speed N (rpm) (%) (%) 3000 3200 3400 3600 3800 4000 4200 4400 4600 4800 5000 5200 5400 5600 5800 6000 Case 1 40.3 0 Case 2 40.0 0 Case 3 41.7 0 Case 4 0 20.0 Case 5 42.0 20.3 Case 6 20.0 11.0 Conven- 0 0 X X X X X tional example

[0053] As is obvious from Table 1, regarding Cases 1 and 3 to 6, the surface roughness of the finished surface was very small at all the rotation speeds, and satisfactory results were obtained. Also regarding Case 2, the surface roughness of the finished surface was satisfactory to some extent at only two points of 4800 rpm and 5600 rpm, and very good results were obtained as a whole. On the other hand, the conventional example has x at 4200 rpm to 5000 rpm, which is a problem, since the rotation speed in this range is particularly a range used normally in a circular saw blade. As a result, a satisfactory finished surface having small surface roughness was obtained through cutting with the circular saw blade to which the present invention was applied, and the present invention was shown to be effective.

[0054] In the embodiments described above, as the vibration prevention mechanism for preventing vibration of the metal base, the slots filled with the resin are used, but a vibration prevention plate or the like may be attached to the metal base instead. Moreover, in the embodiments, the cutting teeth are fixed by means of brazing, but the means for fixing the cutting teeth is not limited thereto and may be resistance welding, a high-powered beam such as a laser, or the like. Additionally, the embodiments described above are merely examples, and various changes may be made without departing from the gist of the present invention.

REFERENCE NUMERALS

[0055] 10, 20, 30, 40 circular saw blade [0056] 11, 21, 31, 41 metal base [0057] 13a to 13f, 23, 23a to 23c, 33, 33a to 33g, 43, 43a to 43d tooth body [0058] 14a to 14f, 28, 28a to 28c, 38, 38a to 38g, 48, 48a to 48d cutting teeth [0059] 15a to 15f, 24, 24a to 24c, 34, 34a to 34g, 44, 44a to 44d gullet [0060] 26, 36, 46 outer slot [0061] 27, 37, 47 inner slot