JP2017001099A - Circular saw blade with insert - Google Patents

Abstract

The present invention provides a circular saw blade in which a cut surface of a work material is not damaged by chips. A circular saw blade has a disk-shaped base metal 2 and a chip 4 joined to the base metal 2 so as to protrude in the radial direction from the outer periphery of the base metal 2. The chip 4 has a flank 4a facing radially outward and a side surface 4b1 positioned at one end of the flank 4a in the thickness direction. A chamfer 4c1 having a chamfering angle θ with respect to the flank 4a is formed between the flank 4a and the side surface 4b1. A cutting edge 4d for cutting the work material is located at one end in the circumferential direction of the flank 4a. A groove 4f is formed in the flank 4a so as to extend in the circumferential direction from the cutting edge 4d. The groove 4f has a first groove end 4h located at the cutting edge 4d and a second groove end 4i located farther from the chamfer 4c1 than the first groove end 4h. The first groove end 4h has a groove end angle φ of 40 ° or more and 60 ° or less with respect to the flank 4a. Further, the groove end angle φ is larger than the chamfering angle θ, and the difference between the groove end angle φ and the chamfering angle θ is 15 ° or less. [Selection] Figure 5

Description

  The present invention relates to a circular saw blade having a disk shape and a plurality of chips mounted on the outer periphery.

  The circular saw blade described in Patent Document 1 has a disk-shaped base metal and chips that are joined to the outer periphery of the base metal at predetermined intervals in the circumferential direction. The tip of the tip protrudes in the radial direction from the base metal, and the tip cuts the workpiece by rotating the circular saw blade. The tip is a substantially rectangular parallelepiped, and has a flank face that faces radially outward and side surfaces that are positioned at both ends of the flank face in the thickness direction. A chamfer is formed between the flank and each side.

  A groove extending in the circumferential direction from the cutting edge is formed on the flank. Therefore, the chips cut out from the work material by the insert are divided in the width direction of the cutting edge by the grooves. Thus, the welding of chips on the cut surface is suppressed, and the work material can be cut at a high speed by the circular saw blade. Further, the groove has an inclined surface having an inclination angle with respect to the flank. The inclination angle of the groove is set to be the same as the inclination angle with respect to the chamfering flank. Thus, the chips are discharged in a direction parallel to the cut surface of the work material, and the cut surface is prevented from being damaged by the chips.

Japanese Patent No. 3505476

  However, when the work material is cut with the circular saw blade described in Patent Document 1, the chips discharged from the work material are actually not parallel to the cutting surface but in the center of the cutting blade in the width direction. . As a result, the cut surface may be damaged by chips. Therefore, there is a need in the art for a circular saw blade in which the cut surface of the work material is not damaged by the chips.

  The present invention is a circular saw blade having the configuration as described in each claim. According to one aspect of the present invention, a circular saw blade with a chip includes a disk-shaped base metal and a chip bonded to the base metal so as to protrude in the radial direction from the outer periphery of the base metal. The tip has a flank face that faces outward in the radial direction and a side face that is located at one of both ends of the flank face in the thickness direction. A chamfer having a chamfer angle with respect to the flank is formed between the flank and the side. A cutting blade for cutting the work material is located at one end in the circumferential direction of the flank. A groove is formed in the flank so as to extend from the cutting edge in the circumferential direction. The groove has a first groove end located at the cutting edge and a second groove end located at the cutting edge and farther from the chamfer than the first groove end. The first groove end has a groove end angle of 40 ° or more and 60 ° or less with respect to the flank. Further, the groove end angle is larger than the chamfer angle, and the difference between the groove end angle and the chamfer angle is 15 ° or less.

  The work material to be cut with the circular saw blade is, for example, a rod shape, and the first and second cut surfaces are formed on both sides of the circular saw blade by cutting with the circular saw blade. Since the thickness of the circular saw blade is, for example, about 1.5 mm and is generally thin, the distance between the first and second cut surfaces is relatively narrow. Chips cut out from the work material by the insert are discharged between the narrow first and second cut surfaces. The chips are divided in the width direction of the cutting edge by the groove of the chip.

  The chip discharge angle is affected by the chamfering and groove shape. As described above, the groove end angle is larger than the chamfer angle. Moreover, the difference between the groove end angle and the chamfer angle is 15 ° or less. Therefore, the chips are discharged inwardly (in the width center direction) slightly in parallel with the cut surface. As a result, the cut surface is less likely to be damaged by chips. Therefore, it can be avoided that the chips contact the opposite cut surface. Thereby, the cut surface on the opposite side is less likely to be damaged by chips.

  Therefore, in the present invention, the chips are discharged in the direction of the center of the width of the cutting blade at a relatively small inclination angle substantially parallel to the cutting surface. Thus, the two cut surfaces are less likely to be damaged by chips. By cutting the work material in this way, the cut surface of the work material is finished cleanly. Thus, it is possible to avoid a step of polishing the cut surface in a subsequent step.

  Further, the groove end angle is 40 ° or more and 60 ° or less. When the groove end angle exceeds 60 °, the angle of the corner formed between the groove and the clearance surface becomes small. For this reason, when the groove end angle exceeds 60 °, chipping easily occurs due to thermal cracks or the like. Therefore, in the present invention, since the groove end angle is 60 ° or less, the durability of the chip can be kept high. When the groove end angle is less than 40 °, the groove becomes shallow if the width of the groove is constant. Therefore, the bottom of the groove comes into contact with the work material, and the work material is cut even at the bottom of the groove. This prevents chips from being separated by the grooves. Therefore, in this invention, since a groove end angle is 40 degrees or more, it can avoid that a chip | tip contacts the bottom of a groove | channel, and a chip | tip can be isolate | separated.

It is a side view of a circular saw blade. It is a partially expanded side view of a circular saw blade. It is a partially expanded plan view of a circular saw blade. It is a partially expanded plan view of a circular saw blade. It is a partially expanded front view of a circular saw blade. It is an idea figure which shows the relationship between a chip | tip and feed at the time of cut | disconnecting a workpiece material with a circular saw blade. It is sectional drawing of the chip cut | disconnected from the workpiece by the circular saw blade. It is a table | surface which shows the experimental result at the time of cut | disconnecting a cut material with the circular saw blade provided with various inserts. It is a photograph of the cut surface of the work material in a clean state. It is the photograph of the cut surface in an allowable state. It is the photograph of the cut surface in an unacceptable state. It is the photograph of the cut surface in a state with many cracks. It is a figure which shows the relationship between the magnitude | size difference of a groove end angle and a chamfering angle, and surface evaluation. It is a table | surface which shows the relationship between the difference of the magnitude | size of a groove end angle and chamfering angle in each twist degree, and a groove end angle. It is a partial expanded front view of a chip | tip provided with the groove | channel concerning another structure. It is a partial expanded front view of a chip | tip provided with the groove | channel concerning another structure.

  One embodiment of the present invention will be described with reference to FIGS. As shown in FIG. 1, the circular saw blade 1 has a disk-shaped base metal 2 and a plurality of chips 3 mounted on the outer periphery of the base metal 2. The outer diameter of the circular saw blade 1 is, for example, 250 mm to 460 mm. The base metal 2 is made of, for example, steel and has a thickness of, for example, 0.8 mm to 2.5 mm. The base 2 integrally includes a disc-shaped main body 2a and a blade body 2b that protrudes radially outward from the outer periphery of the main body 2a.

  The blade body 2b is formed at a predetermined interval on the outer periphery of the main body 2a as shown in FIGS. A tooth chamber 2d is formed between the blade bodies 2b. The tooth chamber 2d has a width that decreases from the radially outer side toward the center and has a tooth bottom 2e. A concave portion 2c that opens laterally and radially outward is formed on one side of the blade body 2b, and the chip 3 is attached to the concave portion 2c.

  As shown in FIG. 1, for example, 40 to 100 chips 3 are attached to the base metal 2 by brazing or the like. The chips 3 are provided on the base metal 2 at equal intervals. For example, chips 4 and chips 5 having different configurations are provided alternately. The chip 3 is made of a cemented carbide, and is obtained, for example, by mixing tungsten carbide and cobalt as a binder and sintering. The chip 3 may be a cermet such as TiN, TiC, or TiCN. A coating for improving the wear resistance may be applied to the surface of the chip 3.

  As shown in FIGS. 2 to 5, the chip 3 (4, 5) is a substantially rectangular parallelepiped and has flank surfaces 4 a and 5 a facing outward in the radial direction. The flank surfaces 4 a and 5 a are rectangular and have long sides wider than the thickness of the base metal 2. One of the long sides is the cutting edge 4d. The length (blade thickness) of the cutting edge 4d is, for example, 1 mm to 10 mm. The clearance angle 3b between the circumferential tangent at the cutting edge 4d and the clearance surfaces 4a and 5a is, for example, 5 ° to 15 °. The flank surfaces 4a and 5a extend radially outward from the tip of the blade body 2b and project radially outward from the blade body 2b. Cutting edges 4d and 5d are located at the tips of the flank surfaces 4a and 5a.

  As shown in FIG. 2, the chip 3 has rake surfaces 4 e and 5 e extending from the cutting edges 4 d and 5 d toward the center of the base metal 2. The rake angle 3a of the rake face 4e, 5e with respect to the diameter line of the base metal 2 is 0 ° to −30 °. Recesses 4p and 5p are provided in a predetermined region radially inward of the rake faces 4e and 5e. The recesses 4p and 5p are recessed from the rake surfaces 4e and 5e toward the center of the chips 4 and 5 in a side view.

  As shown in FIGS. 2 to 5, the chip 3 has side surfaces 4 b and 5 b at both ends in the thickness direction of the relief surfaces 4 a and 5 a. The side surfaces 4b and 5b are substantially orthogonal to the flank surfaces 4a and 5a, and are substantially parallel to the surface of the base metal 2. Chamfers 4c and 5c are formed between the flank surfaces 4a and 5a and the side surfaces 4b and 5b. The chamfers 4c and 5c have a chamfer angle θ (see FIG. 5) with respect to the flank surfaces 4a and 5a. The chips 4 and 5 each have a pair of chamfers 4c and 5c, and the pair of chamfers 4c and 5c are set to have the same angle.

  Since the circular saw blade 1 generates frictional heat when cutting the work material, heat is repeatedly applied to the chip 3 by repeating the cutting. For this reason, corners with a small angle may be chipped due to heat (thermal cracks). On the other hand, chamfers 4c and 5c are formed at the edges of the flank surfaces 4a and 5a. Therefore, the angle of the corner formed between the flank surfaces 4a and 5a and the side surfaces 4b and 5b is increased by the chamfers 4c and 5c. Therefore, the occurrence of thermal cracks between the flank surfaces 4a and 5a and the side surfaces 4b and 5b is reduced by the chamfers 4c and 5c.

  The chamfers 4c and 5c are planar as shown in FIG. 3, and are formed over the entire length at the edges of the flank surfaces 4a and 5a. The width in the thickness direction of the chamfers 4c and 5c is, for example, 0.05 mm to 0.1 mm, and has substantially the same width over the entire length.

  As shown in FIGS. 3 to 5, grooves 4 f and 5 f for dividing chips are formed on the flank surfaces 4 a and 5 a of the chips 4 and 5. The grooves 4f and 5f extend from the cutting edges 4d and 5d, which are one end of the flank surfaces 4a and 5a, to the other end of the flank surfaces 4a and 5a. The grooves 4f and 5f are V-shaped when viewed from the front, and have a pair of inclined surfaces 4j and 4k that are inclined with respect to the flank surfaces 4a and 5a. The grooves 4f and 5f have a bottom 4m in a region where the inclined surfaces 4j and 4k intersect. The width of the grooves 4f and 5f is, for example, 0.1 to 0.5 mm, and the depth is, for example, 0.1 to 0.3 mm.

  As shown in FIGS. 4 and 5, the groove 4 f has groove ends 4 h and 4 i at the cutting edges 4 d and 5 d. The inclined surfaces of the groove ends 4h and 4i are linear and have a groove end angle φ (see FIG. 5) with respect to the flank 4a. The groove end angles φ of the groove ends 4h and 4i are set to be the same angle. The inclined surfaces 4j and 4k also have the same angle with respect to the flank 4a. The groove 4f extends in the circumferential tangent direction from the cutting edge 4d, and the groove depth decreases as the distance from the cutting edge 4d increases.

  The groove end angle φ is preferably 40 ° or more and 60 ° or less. When the groove end angle φ exceeds 60 °, the angle of the corner formed between the groove 4f and the flank 4a becomes small. Therefore, when the groove end angle φ exceeds 60 °, it tends to be chipped due to a thermal crack or the like. Therefore, the groove end angle φ is preferably 60 ° or less from the viewpoint of durability. When the groove end angle φ is less than 40 °, the groove 4f becomes shallow if the width of the groove 4f is constant. Therefore, the bottom of the groove 4f contacts the work material, and the bottom of the groove 4f also cuts the work material. Thereby, chips are not separated in the groove 4f. Therefore, the groove end angle φ is preferably 40 ° or more from the viewpoint of separating chips.

  The chips 4 and 5 have grooves 4f and 5f as shown in FIG. The groove 4f is deviated from the center line 2g in the thickness direction of the chip 4, and is closer to the first end in the thickness direction of the chip 4 than the center line 2g. On the other hand, the groove 5f of the chip 5 is closer to the second end in the thickness direction of the chip 5 than the center line 2g. The chips 4 and 5 are alternately arranged on the outer peripheral edge of the base metal 2.

  As shown in FIG. 1, the base metal 2 has a mounting hole 2f in the center. The rotary shaft of the circular saw is inserted into the mounting hole 2f. A circular saw machine is used, for example, for cutting various metals, and is used, for example, when cutting a work material at room temperature. When cutting a work material, the circular saw machine advances the circular saw blade 1 in the B direction while rotating the circular saw blade 1 in the A direction. As shown in FIG. 6, the chips 4 and 5 alternately reach the work material while the circular saw blade 1 moves in the B direction (upward).

  4 and 5, the tip 4 has a first chamfer 4c1 at one end in the thickness direction of the flank 4a and a second chamfer 4c2 at the other end. The first chamfer 4c1 and the second chamfer 4c2 have a symmetrical shape with respect to the thickness direction center line 2g. The groove 4f is located in a region closer to the first chamfer 4c1 than the center line 2g in the thickness direction. The groove 4f has a symmetrical shape with the bottom 4m as the center.

  As shown in FIG. 3, chips 4 and chips 5 are alternately mounted on the outer periphery of the base metal 2. The chip 5 has a symmetrical shape with respect to the chip 4 with respect to the center line 2 g in the thickness direction. Therefore, the groove 4f of the chip 4 and the groove 5f of the chip 5 are alternately directed to the work material. As a result, the circular saw blade 1 receives an equal force from the work material against the center line 2g in the thickness direction.

  As shown in FIG. 7, the chips cut from the work material by the chip 4 are divided into chips 6 and 7 by the grooves 4f (see FIG. 6). The chips 6 and 7 have chip main bodies 6a and 7a, chamfer corresponding parts 6b and 7b, and groove corresponding parts 6d and 7d. The chip bodies 6a and 7a have a rectangular cross section and are formed by the cutting edges 4d and 5d of the two chips 4 and 5. A trapezoidal convex portion 6f is formed at the center of the lower edge of the chip body 6a. The side surface of the convex portion 6 f is formed by a groove 5 f of the tip 5 obtained by cutting the work material before the tip 4. The tip side of the convex portion 6f is formed by the cutting edge 4d of the tip 4 obtained by cutting the work material in front of the tip 5.

  As shown in FIG. 7, the chamfer corresponding parts 6b and 7b are parallelograms, and are formed by chamfers 4c and 5c of the two chips 4 and 5. The groove corresponding portions 6 d and 7 d are triangular and are formed by the grooves 4 f of the chip 4.

  As shown in FIG. 1, the circular saw blade 1 is rotated in the A direction and fed in the B direction, and the work material is cut by the circular saw blade 1. The work material is, for example, a rod shape and is cut into a predetermined length. The cut work material is processed as a product by forging or the like. For example, a gear or the like is formed from the cut work material by cold forging.

  The circular saw blade 1 cuts the work material to form two opposing cut surfaces and passes between the two cut surfaces. The cut surface may be damaged by the circular saw blade 1 and the chips 6 and 7 generated during cutting. The scratches on the cut surface also appear in the roughness of the surface of the product subjected to cold forging. For example, a gear tooth is scratched according to a scratch on the cut surface, and the surface roughness of the tooth becomes rough due to the scratch. As a result, the meshing of the gears becomes poor, and abnormal noise may be generated at the meshing parts of the gears. In this embodiment, the cutting direction of the chips 6 and 7 is controlled to reduce the cut surface of the work material from being damaged by the chips 6 and 7.

  As shown in FIGS. 6 and 7, the chips 6 and 7 receive force from the chip 4 when being cut from the work material. Thereby, the chips 6 and 7 are discharged at a predetermined angle in the thickness direction (left-right direction in the figure). When the chips 6 and 7 are discharged in parallel with the cut surface, that is, without an angle with respect to the thickness direction, the chips 6 and 7 theoretically do not damage the cut surface. However, in reality, the chips 6 and 7 may swing in the thickness direction depending on various conditions, and the cut surface may be damaged.

  Therefore, the present inventor considered that chips 6 and 7 are discharged almost inwardly (in the width center direction) substantially parallel to the cut surface. Moreover, since the chips 6 and 7 pass between the two cut surfaces, it was considered that the chips 6 and 7 did not reach the opposite cut surface. That is, consideration was given to preventing the chips 6 and 7 from reaching the opposite cut surface and damaging the opposite cut surface. The configuration will be described below.

  As shown in FIG. 7, the chip 6 has a symmetrical chip body 6a and a symmetrical convex part 6f. Furthermore, the chip 6 has a chamfering corresponding portion 6b on the outer side in the thickness direction, and a groove corresponding portion 6d on the center side in the thickness direction. Accordingly, the chips 6 are discharged at a predetermined angle in the thickness direction due to the difference between the force received by the chamfering corresponding portion 6b from the chip 4 and the force received by the groove corresponding portion 6d from the chip 4.

  As shown in FIG. 7, the force F1 in the thickness direction received by the chamfer corresponding portion 6b is obtained as in the following equation (1). That is, F1 is obtained by multiplying the thickness by the length to obtain the area of the chamfer corresponding portion 6b and multiplying by the force direction component. The force F2 in the thickness direction received by the groove corresponding portion 6d is obtained as in the following formula (2). That is, F2 is obtained by multiplying the thickness by the length and by dividing by 2 because it is a triangle to obtain the area of the groove corresponding portion 6d and multiplying by the force direction component.

(Formula 1) F1 = Sz × cos θ × C / cos θ × F sin θ = F · C · Sz · sin θ
(Equation 2) F2 = Sz × cosφ × Sz / sinφ / 2 × Fsinφ = F · Sz 2/2 · cosφ
Sz is the feed amount of the circular saw blade 1. Specifically, it is the feed amount per chip.
θ is a chamfer angle of the chamfer 4c with respect to the flank 4a.
φ is a groove end angle with respect to the flank 4a of the groove end 4i.
F is a force received from the chip 4 per unit area.

The inventor defined a chip twist degree B expressed by the following formula (3) as a degree of receiving a force in the thickness direction of the chip 6.
(Formula 3) Chip twist degree B = Thickness direction force F1 in chamfering / Thickness direction force F2 in groove
B = F1 / F2 = 2Cs · cos θ / Sz · cos φ≈2 cos θ / cos φ
(Cs≈Sz)

  As the chip twist degree B increases, the angle at which the chip 6 moves toward the center in the thickness direction increases. When chip twist degree B is smaller than 1, it means to go to the thickness direction outside. In addition, Formula 1, Formula 2, and Formula 3 can be applied not only to the chip 6 but also to the chip 7. That is, the force in the thickness direction received by the chamfering corresponding portion 7b of the chip 7 is also obtained as shown in Expression (1). The force in the thickness direction received by the groove corresponding portion 7d is also obtained as shown in Equation (2). Furthermore, the above idea can be applied not only to the chips 6 and 7 cut out from the work material by the chip 4 but also to the chips cut out from the work material by the chip 5.

  As a result of the experiment, it was possible to support the above idea and to find a condition in which neither of the two cut surfaces was damaged. An example of the experimental results is described below.

  A circular saw blade 1 having various chips 4 and 5 was prepared for the experiment. The outer diameter of the circular saw blade 1 is 285 mm, the thickness of the base metal 2 is 1.5 mm, the blade thickness of the chips 4 and 5 is 2.0 mm, and the number of blades is 72. Various chips having groove end angle φ and chamfering angle θ shown in FIG. 8 were prepared as chips 4 and 5. A round bar having a diameter of 40 mm made of SCM420 (chromium molybdenum steel) was prepared as a work material. As processing conditions, the number of rotations was set to 130 rpm, and the feed rate Sz was set to 0.06 mm / tooth.

  The cut surface was visually confirmed and ranked into A to D. Samples of each rank are prepared, and each sample is shown in FIGS. The cut surface of FIG. 9 is rank A and is in a clean state. Specifically, only shallow scratches caused by the tip 3 called so-called knife marks appear on the cut surface, and no deep scratches are seen. Therefore, in rank A, it is considered that the chips do not damage the cut surface.

  The cut surface in FIG. 10 is rank B and is in an acceptable state. Specifically, there are few deep scratches on the cut surface. Therefore, it is considered that the cut surface is hardly damaged by the chips. The cut surface in FIG. 11 is rank C and is in an unacceptable state. Specifically, deep scratches are partially observed in the cut surface, for example, in the region below the cut surface. The cut surface of FIG. 12 is rank D and has many scratches. Specifically, deep scratches are seen on the cut surface in a wide range from the lower right to the center.

  As shown in FIG. 8, chips 4 and 5 having a groove end angle φ of 90 ° and a chamfering angle θ of 30 to 45 ° were prepared. As a chip having a groove end angle φ of 90 °, a chip having a U-shaped groove was prepared. As a result of the experiment, the evaluation of the two surfaces when the work material was cut with the circular saw blade 1 was rank D or rank C, respectively. The chip twist degree B is infinite in any case. Therefore, it is considered that the chips are discharged at an angle greatly away from the adjacent cut surface. From the experimental results, it is considered that the chips reached the opposite cut surface and damaged the opposite cut surface.

  As shown in FIG. 8, chips 4 and 5 having a groove end angle φ of 45 ° and a chamfering angle θ of 25 to 45 ° were also prepared. As a chip having a groove end angle φ of 45 °, a chip having a V shape as shown in FIG. 6 was prepared. As a result of the experiment, when the chamfering angle θ is 45 °, rank C is one of the two evaluations that occur when the work material is cut with the circular saw blade 1. When the chamfering angle θ is 45 °, the chip twist degree B is larger than 1. Therefore, the chips are separated from the adjacent cut surfaces. However, since the angle at which the chips are separated from the adjacent cut surface is not sufficient, it is considered that the chips have damaged the adjacent cut surface.

  As shown in FIG. 8, when the groove end angle φ is 45 ° and the chamfering angle θ is 25 °, one of the two cut surfaces is rank C. Since the chip twist degree B is greater than 1, the chips are separated from the adjacent cut surfaces. However, since the angle at which the chips are separated from the adjacent cut surface is large, it is considered that the chips damaged the opposite cut surface.

  As shown in FIG. 8, when the groove end angle φ was 45 ° and the chamfering angle θ was 30 ° or more and 40 ° or less, the two cut surfaces had rank A or B. Since the chip twist degree B is greater than 1, the chips are separated from the adjacent cut surfaces. Moreover, the angle at which the chips are separated from the adjacent cut surface is relatively small. Therefore, it is considered that it was possible to avoid that the chips reached the opposite cut surface and damaged the opposite cut surface.

  FIG. 13 is a diagram schematically showing the experimental result of FIG. 8 when the groove end angle φ is 45 °. As shown in FIG. 13, when the difference (φ−θ) between the groove end angle φ and the chamfering angle θ is greater than 0 ° and 15 ° or less, the surface evaluation is in the middle of rank A or rank A and B. Become. When the difference between the groove end angle φ and the chamfering angle θ is greater than 0 ° or 15 °, the surface evaluation of the cut surface is rank C or rank D.

  FIG. 14 shows that the idea of Equation (3) corresponds to the experimental result. As shown in FIG. 14, the relationship between the difference (φ−θ) between the groove end angle φ and the chamfer angle θ at each twist degree B and the groove end angle φ is shown. As described above, the groove end angle φ is preferably 60 ° or less from the viewpoint of thermal durability. On the other hand, the groove end angle φ is preferably 40 ° or more from the viewpoint of obtaining a sufficient groove depth for separating chips. From the experimental results, the difference in angle is preferably greater than 0 ° and not greater than 15 ° from the viewpoint of not damaging the two cut surfaces. More preferably, the angle difference is 5 ° or more and 10 ° or less.

  It can be seen from FIG. 14 that when the twist degree B is larger than 2 and smaller than 2.5, it is difficult to damage the cut surface. It can be seen that when the twist degree B is 2.2 or more and 2.4 or less, the cut surface is not damaged more. Therefore, it turns out that a cut surface is hard to be damaged by a chip by making the angle at which a chip is discharged within a predetermined range.

  As shown in FIG. 1, the circular saw blade 1 has a base metal 2 and chips 4 and 5. As shown in FIGS. 2 and 3, the chips 4 and 5 have clearance surfaces 4a and 5a, first side surfaces 4b1 and 5b1, and second side surfaces 4b2 and 5b2. Between the flank surfaces 4a and 5a and the first side surfaces 4b1 and 5b1, first chamfers 4c1 and 5c1 having a chamfering angle θ (see FIG. 7) with respect to the flank surfaces 4a and 5a are formed. Between the flank surfaces 4a and 5a and the second side surfaces 4b2 and 5b2, second chamfers 4c2 and 5c2 having a chamfering angle θ (see FIG. 7) with respect to the flank surfaces 4a and 5a are formed. Cutting edges 4d and 5d for cutting the work material are positioned at one end in the circumferential direction of the flank surfaces 4a and 5a.

  As shown in FIG. 3, grooves 4f and 5f are formed in the flank surfaces 4a and 5a so as to extend in the circumferential direction from the cutting edges 4d and 5d. As shown in FIG. 4, the groove 4f has a first groove end 4h located on the cutting edge 4d and a second groove end 4i located on the cutting edge 4d and located farther from the first chamfer 4c1 than the first groove end 4h. . The first groove end 4h has a groove end angle φ of 40 ° or more and 60 ° or less with respect to the flank 4a. Further, the groove end angle φ is larger than the chamfering angle θ, and the difference between the groove end angle φ and the chamfering angle θ is 15 ° or less.

  The work material to be cut by the circular saw blade 1 is, for example, a rod shape, and the first and second cut surfaces are formed on both sides of the circular saw blade 1 by cutting with the circular saw blade 1. Since the thickness of the circular saw blade 1 is, for example, about 1.5 mm and is thin, the distance between the first and second cut surfaces is relatively narrow. Chips 6 and 7 cut out from the work material by the chips 4 and 5 are discharged between the narrow first and second cut surfaces. The chips 6 and 7 are divided in the width direction of the cutting edges 4d and 5d by the grooves 4f and 5f of the chips 4 and 5, respectively.

  The discharge angle of the chips 6 and 7 is affected by the shapes of the chamfers 4c and 5c and the grooves 4f and 5f. As described above, the groove end angle φ is larger than the chamfer angle θ. Moreover, the difference between the groove end angle φ and the chamfer angle θ is 15 ° or less. Therefore, the chips are not parallel to the cut surface, but are discharged to the center in the width direction so as to be away from the cut surface close to the chamfers 4c and 5c. As a result, the cut surface is less likely to be damaged by chips. Moreover, the chip discharge angle does not have a large angle in the width direction. Therefore, it can be avoided that the chips 6 and 7 contact the opposite cut surface. Thereby, the cut surface on the opposite side is less likely to be damaged by the chips 6 and 7.

  Therefore, in this embodiment, the chips 6 and 7 are discharged in the width center direction of the cutting blades 4d and 5d at a relatively small inclination angle, not parallel to the cutting surface. Thus, the two cut surfaces are less likely to be damaged by the chips 6 and 7. Thus, the cut surface is finished cleanly during cutting. Thus, it is possible to avoid a step of polishing the cut surface in a subsequent step.

  Further, the groove end angle φ is 40 ° or more and 60 ° or less. When the groove end angle φ exceeds 60 °, the angle of the corner formed between the grooves 4f and 5f and the flank surfaces 4a and 5a becomes small. Therefore, when the groove end angle φ exceeds 60 °, it tends to be chipped due to a thermal crack or the like. Therefore, in this embodiment, since the groove end angle φ is 60 ° or less, the durability of the chips 4 and 5 can be kept high. When the groove end angle φ is less than 40 °, the grooves become shallow if the widths of the grooves 4f and 5f are constant. Therefore, the bottoms of the grooves 4f and 5f are in contact with the work material, and the work material is also cut at the bottoms of the grooves 4f and 5f. Thereby, there is a possibility that chips are not separated in the grooves 4f and 5f. Therefore, in this embodiment, since the groove end angle φ is 40 ° or more, it is possible to avoid chips coming into contact with the bottoms of the grooves 4f and 5f.

  The difference between the groove end angle φ and the chamfer angle θ is preferably 5 ° or more. As a result, the chips 6 and 7 are discharged toward the center in the width direction of the cutting edges 4d and 5d so as to be more surely separated from the cutting surfaces close to the chamfers 4c and 5c.

  The difference between the groove end angle φ and the chamfer angle θ is preferably 10 ° or less. Thereby, it is avoided that the chips 6 and 7 advance at a large angle toward the cut surface on the opposite side of the cut surface close to the chamfers 4c and 5c. Thus, the chips 6 and 7 do not reach the opposite cut surface, and damage to the opposite cut surface can be more reliably reduced.

  The grooves 4f and 5f are configured to divide the chips 6 and 7 cut out from the work material in the width direction of the cutting edges 4d and 5d. The groove end angle φ and the chamfer angle θ are set so that the chips 6 and 7 cut out between the chamfers 4c and 5c and the grooves 4f and 5f are discharged toward the center in the width direction of the cutting edges 4d and 5d. Therefore, the cut surface close to the chamfers 4 c and 5 c is less likely to be damaged by the chips 6 and 7.

  The circular saw blade 1 is configured to form first and second cut surfaces that face a work material by cutting the work material. The groove end angle φ and the chamfering angle θ are the first and second cutting times when the chips 6 and 7 cut out between the chamfers 4 c and 5 c and the grooves 4 f and 5 f are cut by the chips 4 and 5. It is set to discharge so that it does not reach both sides. That is, in a time until one of the chips 4 reaches the work material and leaves the work material, the chips cut out from the work material by the chip 4 do not reach both the first and second cut surfaces. Discharged. Accordingly, the chips are less likely to damage both the first and second cut surfaces.

  The grooves 4f and 5f are V-shaped when viewed in the circumferential direction as shown in FIGS. Therefore, the grooves 4f and 5f have a relatively narrow width and a relatively deep structure. Therefore, it is possible to suppress the substantial length of the cutting edges 4d and 5d from being shortened by the grooves 4f and 5f. Further, by deepening the grooves 4f and 5f, the chips 6 and 7 can be prevented from hitting the bottoms 4m and 5m of the grooves 4f and 5f, and the chips 6 and 7 can be divided more reliably.

  As a result of the experiment, it was found that when the difference between the chamfering angle θ and the groove end angle φ is larger than 0 ° and not larger than 15 °, chips hardly damage the cut surface. Further, it was found that the difference between the chamfering angle θ and the groove end angle φ is more preferably 5 ° or more and / or 10 ° or less. Furthermore, it turned out that it is preferable that chip twist degree B is larger than 2.0 and is 2.5 or less. Furthermore, it turned out that it is more preferable that chip twist degree B is 2.2 or more or / and 2.4 or less.

  Although the embodiments of the present invention have been described with reference to the above structure, it will be apparent to those skilled in the art that many alternations, modifications, and changes can be made without departing from the scope of the present invention. Accordingly, aspects of the invention may include all alterations, modifications, and changes that do not depart from the spirit and scope of the appended claims. For example, the form of the present invention is not limited to the special structure, and can be modified as follows.

  The chip 4 may have a groove 8 shown in FIG. 15 instead of the groove 4f shown in FIG. The groove 8 has a planar groove end 8a extending from the flank 4a. The groove end angle of the groove end 8a with respect to the flank 4a is set to the same condition as in the above-described embodiment. That is, the groove end angle is 40 ° or more and 60 ° or less with respect to the flank 4a. The groove end angle is larger than the chamfer angle of the chamfer 4c with respect to the flank 4a. The difference between the groove end angle and the chamfer angle is 15 ° or less, preferably 5 ° or more and / or 10 ° or less.

  As shown in FIG. 15, the groove 8 has a vertical surface 8b extending from the groove end 8a and perpendicular to the relief surface 4a, and an inclined surface 8c connecting the vertical surface 8b and the bottom surface 8d. The bottom surface 8d is parallel to the clearance surface 4a, and the inclined surface 8c has an inclination angle with respect to the vertical surface 8b and the bottom surface 8d, and gently connects the vertical surface 8b and the bottom surface 8d. Since the groove 8 has the vertical surface 8b, the groove 8 can be made relatively deep even if the width of the groove 8 is narrow. Thereby, it can suppress that the chips 6 and 7 contact | connect the bottom face 8d.

  The chip 4 may have a groove 9 shown in FIG. 16 instead of the groove 4f shown in FIG. The groove 9 has a curved groove end 9a extending from the flank 4a. The groove end 9a is curved so that the angle gradually increases from the flank 4a. The groove end 9a has an inclination angle with respect to the flank 4a. Specifically, the groove end 9a has a groove end angle between the tangent line 9d and the flank 4a at a portion intersecting or close to the flank 4a.

  The groove end angle is set to the same conditions as in the above-described embodiment. That is, the groove end angle is 40 ° or more and 60 ° or less with respect to the flank 4a. The groove end angle is larger than the chamfer angle of the chamfer 4c with respect to the flank 4a. The difference between the groove end angle and the chamfer angle is 15 ° or less, preferably 5 ° or more and / or 10 ° or less.

  As shown in FIG. 16, the groove 9 has a vertical surface 9b extending from the groove end 9a and perpendicular to the flank 4a, and a bottom surface 9c parallel to the flank 4a. Since the groove end 9a is curved, the angle change between the groove end 9a and the flank 4a is reduced. Thereby, the change in angle at the groove end 9a is small, and the groove end 9a can be suppressed from being chipped. For example, chipping of the groove end 9a due to repeated application of heat generated during cutting can be reduced.

  The chip 4 shown in FIG. 6 has a pair of chamfers 4c that are targeted with respect to the center line 2g in the thickness direction. That is, the pair of chamfers 4c have the same chamfering angle with respect to the flank 4a. Instead of this, the chip 4 may have a pair of chamfers having different chamfer angles.

  The groove 4f shown in FIG. 6 has a pair of inclined surfaces 4j, 4k and groove ends 4h, 4i, which are targeted around the bottom 4m. That is, the pair of groove ends 4h and 4i have the same groove end angle with respect to the flank 4a. Instead, the groove 4f may have a first groove end 4h and a second groove end 4i having different groove end angles. The first groove end 4h is located closer to the first chamfer 4c1 than the second groove end 4i. The second groove end 4i is located closer to the second chamfer 4c2 than the first groove end 4h.

  In this case, the first chamfer 4c1 and the first inclined surface 4j have the above-described relationship, and the second chamfer 4c2 and the second inclined surface 4k have the above-described relationship. That is, the first groove end angle of the first groove end 4h and the second groove end angle of the second groove end 4i are respectively 40 ° or more and 60 ° or less with respect to the flank 4a. The first groove end angle is larger than the first chamfer angle of the first chamfer 4c1 with respect to the flank 4a. The difference in magnitude between the first groove end angle and the first chamfer angle is 15 ° or less, preferably 5 ° or more and / or 10 ° or less. The second groove end angle is larger than the second chamfer angle of the second chamfer 4c2 with respect to the flank 4a. The difference in magnitude between the second groove end angle and the second chamfering angle is 15 ° or less, preferably 5 ° or more and / or 10 ° or less.

  As shown in FIG. 3, the circular saw blade 1 has chips 4 and 5 alternately one by one. Instead of this, the circular saw blade 1 may have a predetermined number of chips 4 and chips 5 alternately.

  The chamfers 4c and 5c may be flat as shown in FIG. 5 or the like, or may be curved surfaces. When the chamfers 4c and 5c are curved surfaces, the chamfering angles of the chamfers 4c and 5c with respect to the flank surfaces 4a and 5a can be determined by the angle between the tangent line in the vicinity of the flank surface 4a and the flank surface 4a.

  As shown in FIG. 3, the chip 3 may have chamfers 4c and 5c at both ends of the flank surfaces 4a and 5a, or chamfers 4c and 5c only at one end of the flank surfaces 4a and 5a. Also good.

DESCRIPTION OF SYMBOLS 1 Circular saw blade 2 Base metal 3, 4, 5 Tip 4a, 5a Flank 4b, 5b Side surface 4b1, 5b1 1st side surface 4b2, 5b2 2nd side surface 4c, 5c Chamfer 4c1, 5c1 1st chamfer 4c2, 5c2 2nd chamfer 4d, 5d Cutting edge 4e, 5e Rake face 4f, 5f, 8, 9 Groove 4h, 4i, 5h, 5i, 8a, 9a Groove end 4j, 4k Inclined surface 4m, 5m Bottom 6, 7 Chip 6a, 7a Chip body 6b, 7b Chamfer corresponding portion 6d, 7d Groove corresponding portion 6f Protruding portion 9d Tangent line θ Chamfer angle φ Groove end angle

Claims (5)

A circular saw blade with a tip,
A disk-shaped base metal,
Having a chip bonded to the base metal so as to protrude radially from the outer periphery of the base metal;
The tip includes a flank facing outward in the radial direction, a side surface located at one of both ends in the thickness direction of the flank, and a chamfer with respect to the flank formed between the flank and the side surface. A chamfer having an angle, a cutting edge positioned at one end in the circumferential direction of the flank, and a groove formed in the flank so as to extend from the cutting edge in the circumferential direction. And
The groove has a first groove end located at the cutting edge, and a second groove end located at the cutting edge and farther from the chamfer than the first groove end, and the first groove end is the flank face. And the groove end angle is 40 ° or more and 60 ° or less, the groove end angle is larger than the chamfering angle, and the difference between the groove end angle and the chamfering angle is 15 ° or less. Saw blade. A circular saw blade with a tip according to claim 1,
A circular saw blade with a tip, wherein the difference between the groove end angle and the chamfer angle is 5 ° or more. A circular saw blade with a chip according to claim 1 or 2,
A circular saw blade with a tip, wherein a difference between the groove end angle and the chamfer angle is 10 ° or less. A circular saw blade with a tip according to any one of claims 1 to 3,
The groove is configured to divide chips cut out from the work material in the width direction of the cutting blade,
The circular saw blade with a tip is set such that the groove end angle and the chamfering angle are set such that the chips cut out between the chamfer and the groove are discharged toward the center in the width direction of the cutting blade. A circular saw blade with a tip according to claim 4,
The circular saw blade is configured to form first and second cut surfaces that face the work material by cutting the work material,
The groove end angle and the chamfer angle are set so that the chips cut between the chamfer and the groove do not reach both the first and second cut surfaces in the time for cutting the work material by the chip. Circular saw blade with tip that is set to discharge into.