JP2008012625A - Saw blade - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a segment type saw blade capable of simultaneously attaining excellent free-cutting property and improvement of service life performance when performing cutting for a material to be cut made of a hard-brittle material such as concrete and stone material. <P>SOLUTION: This segment type saw blade 1 is constituted by intermittently forming super abrasive grain layers made of diamond abrasive grains or cBN abrasive grains at an outer peripheral edge part of a circular steel substrate 11. In the saw blade 1, at least two cut-out grooves 14 extended from the radial direction inside to the outside and inclined from a rotating direction front side to a rear side are formed with a prescribed space in the peripheral direction on both right and left side faces of the super abrasive grain layers equally arranged by key grooves 13 at the outer peripheral edge part of the steel substrate 11. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a grinding tool that is suitably used for grinding processing such as cutting of various brittle materials such as stone, concrete, tiles, and hard and brittle materials such as castings, and more specifically represented by granite and marble. Natural stone, or artificial stone materials such as artificial marble, tiles, tiles, bricks, siding boards, as well as slab plates made of hard synthetic resin such as fiber reinforced plastics (FRP) and carbon fiber reinforced plastics (CFRP) The present invention relates to a segment type saw blade in which an abrasive layer made of diamond abrasive grains or cBN (cubic nitrogen boron sintered body) abrasive grains for cutting a flat plate or the like with high accuracy is formed.

  In recent years, in addition to various natural stones and artificial marble (hereinafter sometimes simply referred to as “stone”) as building materials, various hard materials as described above are widely used, and work materials made of these hard materials are used. As a grinding tool for cutting a material into a desired size and shape, superabrasive grains (hereinafter simply referred to as “superabrasive grains”) composed of diamond abrasive grains or cBN abrasive grains on the outer peripheral edge of a disk-shaped steel substrate. And a rim type saw blade obtained by continuously and integrally bonding superabrasive layers mainly composed of various binders, and a superabrasive chip composed of the superabrasive grains and various binders. These are roughly divided into segment type saw blades that are intermittently connected at a predetermined interval via key grooves or U grooves provided on the outer peripheral edge of the steel substrate. It is used. These saw blades are usually fastened by being inserted into a spindle of a hand-held rotary power tool such as a grinder or a sander in a state orthogonal to the shaft center, and are used for manual operations such as cutting. When cutting a work material with an electric tool to be used as a hand, excellent free machinability as a saw blade and its life performance are required.

When the abrasive layer of the saw blade that rotates at high speed with the electric tool comes into contact with the work material, frictional heat is generated between the work material and the abrasive layer, and the frictional heat is stored in the superabrasive layer and wears at the same time. However, due to the wear, the free-cutting property as a saw blade is impaired, and further, the life performance as a saw blade is shortened, for example, the abrasive layer is damaged early. Therefore, various attempts have been made to improve the life performance of the abrasive layer by suppressing heat storage to prevent wear and maintaining the free-cutting property as a saw blade stably. For example, in the segment type saw blade, the superabrasive layer is dispersed and fixed in a metal binder phase (bond) forming a superabrasive layer (segment chip), and the entire superabrasive layer has a uniform concentration (concentration). The ratio of superabrasive grains, that is, the concentration of superabrasive grains with respect to the segment chip, has a three-layer structure in which both outer layer portions are in the range of 1.5 to 2.5 times the center layer portion, A saw blade (see, for example, Patent Document 1) equipped with a superabrasive layer in which the superabrasive grain concentration in the entire chip is in the range of 0.88 to 1.54 ct / cm ³ has been proposed.

In addition, the cutting action surface on the outer periphery of the segment chip mainly composed of diamond abrasive grains has a melting point that is substantially the same as the grain diameter of the diamond abrasive grains and higher than the firing temperature of the segment chip, and has a Knoop hardness at room temperature. A saw blade having a segment tip in which 2500 Kg / mm ² of particles are embedded from the cutting action surface of the segment tip to a depth of 1 to 3 times the particle size of the particle, and the segment tip is mounted ( For example, Patent Document 2) is disclosed.

According to the saw blade disclosed in Patent Document 1 in the above prior art, the sharpness is ensured by suppressing the concentration of superabrasive grains in the center layer among the segment chips having a three-layer structure, and both sides thereof are secured. It was reported that by increasing the concentration of the superabrasive grains, it was possible to prevent wear of the outer peripheral edge at the tip of the segment tip and to improve the life performance while ensuring good sharpness. The saw blade has a life-span performance by constructing a segment tip embedded with dummy particles having a high melting point and Knoop hardness, which is different from superabrasive grains, to a predetermined depth from the cutting action surface of the segment tip. It was reported that stable free machinability was provided while maintaining a high level, both for stable free machinability and improved life performance as a saw blade. Information, certain results each has been confirmed.
JP 2002-18729 A JP 2002-46071 A

  However, when the work material is cut by the saw blade, a large amount of swarf is generated by the ground work material, but the discharge of the swarf does not progress smoothly, and the gap between the saw blade and the work material In addition to increasing the cutting resistance, the accuracy of the cut surface of the work material is remarkably reduced, and frictional heat is generated to increase the heat storage of the segment tip and simultaneously reduce the cutting speed. So-called neck wear occurs at the interface between the substrate and the substrate, and the life performance as a saw blade is significantly reduced. Therefore, the saw blade is strongly required to efficiently discharge the generated chips, but the above-mentioned conventional technology does not take sufficient measures against such a problem, and remains as an unsolved problem. It was. Further, when the bonding strength between the steel substrate and the segment tip is insufficient, there is a concern that the segment tip may be damaged due to an impact at the time of cutting on the work material, which is one of the major issues to be solved. In addition, on both the left and right side surfaces of both outer layers of the segment chip in the saw blade of Patent Document 1, grooves are formed that open from the inner side to the outer side in the radial direction of the substrate in order to increase chip discharge and cooling efficiency of the segment chip. However, since the groove portion is a groove that divides the side surface of the segment chip in the radial direction and one is formed on each side surface, chip discharge is insufficient and free cutting is performed. There is a problem that both the property and the bonding strength are not sufficient.

  Thus, the sharpness required for segment type saw blades and the improvement of the life performance, that is, the free-cutting property and the life performance are always in a trade-off relationship. When the concentration of abrasive grains is kept low, the binder metal phase wears out early, and the life performance of the superabrasive layer itself is significantly reduced.

  Therefore, the object of the present invention is to maintain the bonding strength between the steel substrate and the segment chip, smooth the discharge of chips, and at the same time achieve excellent free-cutting properties and improved life performance. It is to provide a segment type saw blade.

  As a result of intensive studies aimed at solving the problems remaining in the saw blade, the present inventors have found that the abrasive layer is evenly distributed by the keyway formed on the outer peripheral surface of the steel substrate. In the segment type saw blade, by forming notched grooves in a predetermined form on both the left and right side surfaces of the superabrasive grain layer, in addition to improving the free-cutting property by the edge effect of the notched grooves, The present invention has been completed by paying attention to the fact that chips generated during cutting of the cutting material are efficiently discharged.

  That is, the present invention provides a segment type saw blade in which a superabrasive layer made of diamond abrasive grains or cBN abrasive grains is intermittently formed on the outer peripheral edge of a circular steel substrate. At least two notch grooves extending from the inside in the radial direction to the outside and inclined from the front to the back in the rotational direction are predetermined in the circumferential direction on the left and right side surfaces of the superabrasive grain layer equally distributed by the key groove at the outer peripheral edge. The saw blade is characterized by being formed with an interval of.

  In the present invention, the notch groove is formed with a length of 50% or more and less than 95% of the height of the superabrasive layer from the outer peripheral end of the superabrasive layer to the axial direction. The above-mentioned saw blade is provided.

  Further, the present invention provides the superabrasive grains in which the notch grooves are formed symmetrically on both the left and right side surfaces of the superabrasive grain layer, and the notch grooves defined by the circumferential notch grooves are not formed. The saw blade is characterized in that the area of the superabrasive grain layer part in the rotational direction in the layer part is larger than the area of each of the other superabrasive layer parts. To do.

  Further, according to the present invention, the notch grooves are formed at different intervals on the left and right side surfaces of each superabrasive grain layer, and at different positions in the side view between the corresponding side surfaces, but with different phases. The saw blade is provided.

  Further, the present invention provides the saw blade, wherein the side surface area of the notch groove is 20 to 40% with respect to the surface area of the left and right side surfaces of the superabrasive grain layer. .

  Further, the present invention provides the saw blade, wherein the depth of the notch groove is substantially the same as 1/2 of the difference in thickness between the steel substrate and the superabrasive layer. Is.

  According to the saw blade of the present invention, the left and right side surfaces of the superabrasive grain layer equally distributed by the key groove on the outer peripheral edge of the circular steel substrate extend from the inner side in the radial direction and from the front to the rear in the rotation direction Due to the action of at least two notched grooves inclined toward the surface, the chips generated when cutting the work material are efficiently discharged out of the system, and the chips remaining in the gap between the substrate and the work material Friction heat and heat storage of the frictional heat in the abrasive layer can be greatly suppressed, and the wear of the superabrasive layer caused by the heat storage of the superabrasive layer and the reduction in cutting performance are obviated. The excellent free-cutting performance is prevented over a long period of time. In addition, the so-called neck wear that occurs at the interface between the substrate and the superabrasive layer due to chips remaining between the substrate and the work material is prevented, and the sound state as a saw blade is also maintained. . The saw blade according to the present invention further reduces the contact area between the work material and the superabrasive layer at the time of cutting by at least two notched grooves provided on both the left and right side surfaces of the superabrasive chip, to the saw blade itself. It is possible to improve the cutting speed by reducing the resistance of the superabrasive grains from the outer peripheral edge in the axial direction without providing the notch groove so as to cross the entire height direction of the superabrasive grain layer. By forming with a length of 50% or more and less than 95% of the layer height, a sufficient bonding area is ensured between the superabrasive layer and the substrate, and the substrate and the superabrasive layer are also cut during the cutting operation. It is possible to effectively suppress neck wear that occurs at the interface with the head. Further, the notch grooves formed on the left and right side surfaces of the superabrasive layer are formed at different intervals on the left and right side surfaces of each superabrasive layer and with different phases between the corresponding side surfaces. And the formation area of the notch grooves formed on both the left and right side surfaces of the superabrasive layer is in the range of 20 to 40% with respect to the surface area of both sides of the superabrasive layer, By making the groove depth approximately the same as the thickness clearance between the abrasive layer on one side and the steel substrate, the strength of the superabrasive layer is sufficiently secured, and the life performance of the saw blade itself is greatly increased. To improve. The effect of the present invention will be further described. In the conventional superabrasive layer forming means in the above-mentioned prior art, three superabrasive layers having different concentrations are provided in three layers to form segment chips, or a predetermined depth from the grinding surface. The cost of the saw blade itself is significantly increased due to the complicated process of forming the abrasive layer, such as forming a segment chip by embedding dummy particles on the surface, but the formation of the super abrasive layer according to the present invention Since it can be formed in almost one process, its manufacturing process is greatly omitted, and as a result, it is possible to provide a saw blade at a low price.

  BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the best mode for carrying out the present invention will be described in more detail based on FIGS. 1 to 5 and the attached examples. However, the present invention is not restricted thereby, and the gist of the present invention is described below. The design can be changed freely within the range.

  1 is a front view of a saw blade according to an embodiment of the present invention, FIG. 2 is a cross-sectional view taken along the line A-B-C-D in FIG. 1, and FIG. 3 is a line E-E in FIG. 4 is an enlarged cross-sectional view taken along line FF in FIG. 1, and FIG. 5 is an enlarged side view of a main part for explaining the shape of the cut groove in the segment chip. In addition, in this specification, when there is no description of the reference | standard which makes a direction clear, a "front" direction says the rotation direction side in the circumferential direction of a saw blade, and a "rear" direction says the reverse direction.

  The saw blade according to the present invention is a superabrasive layer (hereinafter referred to as diamond abrasive grains or cBN abrasive grains) as a main component on the outer peripheral edge of a disk-shaped steel substrate (hereinafter also referred to simply as “substrate”). In some cases, the “superabrasive layer” is sometimes referred to as “abrasive layer”), but the outer periphery is formed intermittently through a keyway formed at a predetermined interval on the outer peripheral edge of the substrate. As a segment type saw blade with a diameter of 100 to 250 mm, for example, it is inserted into a spindle of a rotary electric tool such as a disk grinder or a sander in a state orthogonal to the axis, and is applied to a work material such as concrete, stone, or tile. It is used extensively for cutting and the like.

  Here, as shown in FIG. 1, the saw blade 1 in the embodiment of the present invention is arranged on the outer peripheral edge of the circular steel substrate 11 from the radial inner side I to the outer side U, and from the rotational direction front X to the rear. A key groove 13 inclined substantially radially toward Y is formed so as to divide the outer peripheral edge portion of the substrate 11 into 12 equal parts, and the abrasive layer 12 is equally distributed on each of the divided outer peripheral edge parts. In addition, the saw blade of the present invention is configured by being bonded and fixed integrally. At this time, on the left and right side surfaces of the abrasive grain layer 12, as shown in FIG. 1, two radially extending from the inner side I to the outer side U and inclined substantially radially from the front X to the rear Y in the rotational direction. The length of the notch groove 14 is the height of the abrasive grain layer 12, that is, from the outer peripheral end 17 of the abrasive grain layer 12 toward the axial center of the substrate 11. 50% or more and less than 95%, preferably 60 to 85% of the dimension up to the bonding interface 18 between the substrate 11 and the abrasive grain layer 12 by selecting such a structure. In this case, a sufficient bonding area is ensured, and the strong bonding of the abrasive grain layer 12 to the substrate 11 is ensured. At the same time, so-called neck wear during cutting work on the work material can be prevented. The cut-out groove 14 in this example has a radial shape that is convex forward in the rotational direction extending outward from the center of the substrate (see the cut-out groove 14a in FIG. 5). The side view shape of 14 is not limited to this, For example, linear shape may be sufficient.

  In addition, two notch grooves 14 are provided on each of the left and right side surfaces of the abrasive layer 12 so as to be inclined substantially radially from the front to the rear in the rotational direction, and different intervals are provided on the left and right side surfaces of the individual abrasive layer 12. Thus, by forming a phase difference between the corresponding side surfaces, the chips of the work material generated during the cutting operation are efficiently discharged, and the neck wear caused by the chips is reduced. In addition, it is possible to prevent this from occurring and to ensure excellent finishing accuracy on the grinding surface of the work material, and to effectively compensate for the strength reduction of the abrasive grain layer 12 caused by the formation of the notch grooves 14.

In the notch groove 14 of this example, it is formed with the space | interval which differs in the circumferential direction in the right and left both sides | surfaces of each abrasive grain layer 12 from the front end 121 of the said abrasive grain layer 12 to each notch groove 14. Means that the dimensions to the center of the left and right sides are different on the left and right side surfaces. Specifically, as shown in FIG. 3, the first notch groove 14a is formed on the right side surface (upper side surface in FIG. 3) of the abrasive grain layer 12. When the second notch groove 14b is formed and the third notch groove 14c and the fourth notch groove 14d are formed on the left side surface (lower side surface in FIG. 3) of the abrasive grain layer 12, the abrasive on the right side surface is formed. Dimensions l ₁ and l ₂ from the front end 121 of the grain layer 12 to the center of the first notch groove 14a and the center of the second notch groove 14b are the third from the front end 121 of the abrasive grain layer 12 on the left side. Distance to the center of the notch groove 14c and the center of the fourth notch groove 14d _3, it means that l ₄ to be different sizes, respectively. Further, the fact that the phase is changed between the corresponding side surfaces means that the cut-out groove on the right side and the cut-out groove on the left side are not in positions facing each other in side view, that is, in FIG. As shown, it means that all the cutout grooves 14a to 14d do not have a slight overlapping portion in a side view. Thereby, the thickness of the abrasive grain layer 12 is prevented from being partially reduced, and the strength of the abrasive grain layer 12 is prevented from being lowered.

  In the saw blade of the present invention, the notch groove arrangement form is not limited to the asymmetric form on both the left and right side surfaces. For example, the notch groove arrangement on the left and right side surfaces of each abrasive grain layer is symmetrical. Form may be sufficient. In this case, as shown in FIG. 5, for example, a superabrasive layer portion in which notch grooves defined by circumferential notch grooves 14a and 14b on the side surface of the abrasive grain layer 12 are formed, that is, a segment chip. The first superabrasive layer portion (side area) 141 formed by the front end 121 of the abrasive grain layer 12 and the center line 91 of the notch groove 14a, the center line 91 of the notch groove 14a, and the center of the notch groove 14b. The second superabrasive layer portion 142 formed by the line 92 and the center line 92 of the notch groove 14 b and the third superabrasive layer portion 143 formed by the rear end 122 of the abrasive layer 12, It is desirable that one superabrasive layer portion 141 is larger than the area of each of the second superabrasive layer portion 142 and the third superabrasive layer portion 143. Thereby, in the segment chip, since the area of the abrasive grain layer in the front part that receives the impact first is large, the segment chip is excellent in strength.

  As shown in FIG. 1, the two notched grooves 14 formed on the left and right side surfaces of the abrasive grain layer 12 in the present embodiment have the sum of the areas of the side surfaces of the groove part as shown in FIG. In contrast, it is desirable that each of them is formed within a range of 20 to 40%, preferably 20 to 30%. By forming the notch groove 14 as described above, the work material during the cutting operation is formed. It is possible to reduce the contact area while maintaining the edge effect against the above, to maintain the cutting speed at a high level, and to compensate for the decrease in strength of the abrasive layer 12 in a well-balanced manner.

  In the present embodiment, the groove depth 42 of the two notched grooves 14 formed on the left and right side surfaces of the abrasive layer 12 is 1 of the difference between the thickness of the substrate 11 and the thickness of the abrasive layer 12. / 2 That is, it is desirable that the clearance is substantially the same as the clearance between the substrate 11 and the abrasive grain layer 12 on one side, but the specific edge effect is brought about by specifying the depth of the notch groove 14 in this way. At the same time, it is possible to minimize the decrease in the strength of the abrasive grain layer 12 caused by forming the notch groove 14 while efficiently discharging the chips. As described above, according to the saw blade 1 in the above-described embodiment based on the present invention, the two problems of the sharpness and the sharpness that are usually in a trade-off relationship and the free cutting ability represented by the cutting speed and the improvement of the life performance are combined. A segment type saw blade that can be achieved can be provided to the market at a relatively low cost. In addition, it is desirable that the shape of the cutout groove according to the present invention, that is, the length in the radial direction, the groove area, and the groove depth are the same in all the cutout grooves.

  In the present invention, the cross-sectional shape of the notch groove is not particularly limited, and the wall surface constituting the notch groove extends vertically upward from the groove bottom surface, and the wall surface constituting the notch groove is above the groove bottom surface. In addition, a trapezoidal cross-sectional groove extending inward of the groove, and a reverse trapezoidal cross-sectional groove in which the wall surface forming the notch groove extends upward from the groove bottom surface and outward of the groove, among which the rectangular cross-sectional groove and the reverse trapezoidal cross-sectional groove are easy to process. It is preferable in a certain point.

  Punching is performed using a commercially available carbon tool steel with a plate thickness of 1.2 mm as a raw material, and a circular plate-like body having an outer diameter of 92 mm is formed with a mounting hole 15 having an inner diameter of 20 mm. The outer periphery of the body is divided into 12 parts, a key groove 13 having a width of 2.0 mm which is inclined substantially radially from the front to the rear in the rotational direction is provided, and the plate shape is equally distributed into 12 parts by the key groove 13 The outer peripheral edge portion of the body was previously processed so that the plate thickness of the portion was slightly reduced to form the abrasive layer bonding portion 16 to obtain a steel substrate 11 according to this example. On the other hand, the abrasive grain layer 12 according to this example comprises a bond matrix made of nickel + bronze mixed metal powder and a diamond abrasive grain having a mixing ratio to the bond matrix, that is, a concentration of 18% in the presence of a binder. The mixed powder obtained by mixing is embossed on the abrasive layer joint 16 at the outer peripheral edge of the substrate 11, heated to 900 ° C. in a furnace, and then cooled to remove the abrasive layer 12. The so-blade 1 according to this example having an outer diameter of 105 mm as shown in FIG. 1 was obtained by the so-called simultaneous sintering method in which the firing of the abrasive layer 12 and the bonding of the abrasive grain layer 12 to the substrate 11 were carried out simultaneously.

  At this time, the mold according to this embodiment used for the die pressing has a finished dimension after sintering the abrasive grain layer 12 and its height 43, that is, from the outer peripheral edge of the abrasive grain layer 12 to the axial direction substrate 11. As shown in FIG. 4, the distance to the interface is 8.5 mm, and is inclined substantially radially from the rear to the front in the rotational direction from the outer peripheral edge of the mold toward the center of the mold. A notch groove 14 having a predetermined size and shape is provided in the circumferential direction as shown in FIGS. 1 and 5 on both left and right side surfaces of the abrasive grain layer 12 formed by the protrusion. The two notched grooves 14 are formed at different intervals on the left and right sides of the abrasive grain layer 12 as shown in FIG. It does not exist in the opposite position in the side view between the corresponding side surfaces, And has a structure formed by changing the phase.

  The thickness 44 of the abrasive grain layer 12 according to the present embodiment formed by being pressed by the mold is 1.6 mm, and the clearance 41 between the substrate 11 and the abrasive grain layer 12 is 0.00 as shown in FIG. The specific dimensions of the two notch grooves 14 formed on each of the left and right side surfaces of the abrasive grain layer 12 are 2 mm, and the width per notch groove 14 is 3.7 mm. The length in the axial direction is 6.8 mm, and the sum of the side surface areas of the two notched grooves 14 with respect to the one side surface area of the abrasive grain layer 12 is approximately 24%. The length of the groove 14 is approximately 80% of the height 43 of the abrasive grain layer 14. Further, the depth 42 of the notch groove 14 is formed in a finished dimension of 0.2 mm. As shown in FIG. 4, the clearance 41 between the thickness of the abrasive grain layer 12 and the thickness of the substrate 11 and the notch groove 14 are formed. The depth is substantially the same.

(Straight line cutting test)
The segment type diamond saw blade 1 produced in Example 1 was fastened and fixed to a spindle of a grinder, and a cutting test of straight cutting was performed on a concrete flat plate having a thickness of 60 mm under the following test conditions. . In addition, the cutting test of the straight line cutting was performed using three saw blades having the same specifications (denoted as saw blades 1, 2, and 3 in Table 1). The saw blade was evaluated by measuring the average cutting time per cut and the amount of wear on the outermost peripheral surface of the saw blade after 15 m cut. The amount of wear on the outermost peripheral surface of the saw blade is a reduction in the amount of wear in the radial direction.

(Cutting test conditions)
The cutting test does not cut (divide) the work material, but inserts a cut of a predetermined depth into the work material, cuts it for one cut length, and repeats this for 50 cuts. is there.
・ Electric power tool used: 12,000 rev / min ・ Cutting depth: 24 mm
・ 1 cut length: 30cm
・ Total cutting length: 15m with 50 cuts

Comparative Examples 1 and 2
A diamond saw blade having substantially the same specifications as in Example 1 was used, except that it was a commercially available segment type diamond saw blade and that no cut grooves were formed on the left and right side surfaces of the superabrasive grain layer. In addition, this commercial item tested each using two sheets of the same specification (in Table 1, it describes as commercial item 1 and 2).

  From the results shown in Table 1, the saw blade of the example has a so-called edge effect in which the edges of the notch grooves formed on the left and right side surfaces of the abrasive layer bite into the work material sharply, and has a sharp sharpness that can withstand high-speed cutting. , The chips generated at the time of cutting are efficiently discharged, the heat accumulation of the abrasive layer is effectively suppressed, there is no breakage of the abrasive layer due to wear under the neck, the cutting time per cut is short, The amount of wear was also small. Further, when the ground surface was visually observed, it was confirmed that the ground surface having excellent processing accuracy was repeatedly obtained for the saw blade of the example with respect to the comparative product. For this reason, it is clear that the saw blade of the example significantly improves the life compared to the comparative example.

  As a material for forming the circular substrate according to the present invention, usually commercially available carbon tool steel is preferably used, but is not particularly limited as long as it has a certain rigidity and mechanical strength. It can be used by appropriately selecting from steel. The saw blade formed by the present invention is not particularly limited as long as it is a segment type saw blade having an outer diameter of 100 mm or more and less than 355 mm, and can be applied to a wide variety of saw blades. Further, the means for joining the abrasive layer to the steel substrate employs a simultaneous sintering method in which the sintering of the abrasive grain layer and the joining of the abrasive grain layer to the substrate are simultaneously performed in the above embodiment. The method is not particularly limited as long as the two are firmly joined, and does not preclude appropriately adopting a conventionally known method such as welding or brazing. In the above embodiment according to the present invention, the binder metal material for forming the abrasive layer together with the diamond abrasive grains, that is, the nickel + bronze mixed metal powder is adopted as the bond matrix. However, in the present invention, other bond matrixes are used. For example, various bond matrices made of iron, cobalt, tungsten carbide, or a mixture thereof can be mixed at a predetermined mixing ratio in the presence of various binders.

  As described above in detail, the saw blade according to the present invention having the above configuration is fastened to a spindle of a rotary electric tool such as a grinder or a sander in a state of being orthogonal to various hard and brittle materials represented by concrete, stone, tile and the like. When performing cutting processing, etc., it facilitates high-speed cutting, etc. due to sharp sharpness, in addition, the chips of the work material are efficiently discharged, heat storage of the abrasive layer is suppressed, and contact between the work material and the abrasive layer By reducing the area, the resistance to the saw blade is reduced, and the accuracy of the ground surface can be stably maintained simultaneously with the cutting speed. In addition, by making various improvements to the formation area and form of the notch grooves formed in the abrasive layer, the rigidity as a cutting tool is maintained at a high level while ensuring the above characteristics, and the comfort as a saw blade is achieved. It is expected to be widely adopted in the industrial field because it can significantly improve the life performance in combination with machinability and can be provided to the market at a low price.

The front view of the saw blade in embodiment which concerns on this invention. Sectional drawing seen along the ABCD line | wire of FIG. The expanded sectional view seen along the EE line of FIG. The expanded sectional view seen along the FF line of FIG. The principal part enlarged side view for demonstrating the form of the notch groove in a segment chip | tip.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Saw blade 11 Steel substrate 12 Abrasive grain layer 13 Key groove 14, 14a-14d Notch groove 15 Mounting hole 16 Abrasive layer joint part 17 Outer peripheral edge 41 Clearance 42 Depth of notch groove 43 Abrasive grain layer height 44 Abrasive Layer Thickness 121 Segment Chip Abrasive Layer Front End 122 Segment Chip Abrasive Layer Rear End

Claims (6)

  In a segment type saw blade in which a superabrasive layer made of diamond abrasive grains or cBN abrasive grains is intermittently formed on the outer peripheral edge of a circular steel substrate, a key groove is formed on the outer peripheral edge of the steel substrate. At least two notch grooves extending from the inside in the radial direction to the outside and inclined from the front to the back in the rotational direction are formed on the left and right side surfaces of the superabrasive grain layer equally distributed by A saw blade characterized by being made.   The notch groove is formed with a length of not less than 50% and less than 95% of the height of the superabrasive layer from the outer peripheral end of the superabrasive layer in the axial direction. The saw blade according to Item 1.   The notch grooves are formed symmetrically on both the left and right side surfaces of the superabrasive grain layer, and rotate in each superabrasive layer portion in which the notch grooves defined by the circumferential notch grooves are not formed. 3. The saw blade according to claim 1, wherein an area of a superabrasive grain layer portion forward in the direction is larger than each area of each of the other superabrasive grain layer portions.   The notch grooves are formed at different intervals on the left and right side surfaces of each superabrasive grain layer, and at different positions in the side view between the corresponding side surfaces, but with different phases. The saw blade according to claim 1 or 2.   The saw blade according to any one of claims 1 to 4, wherein a side surface area of the notch groove is 20 to 40% with respect to a surface area of each of the left and right side surfaces of the superabrasive grain layer. .   The depth of the notch groove is substantially the same as one half of the difference in thickness between the steel substrate and the superabrasive grain layer, according to any one of claims 1 to 5. Saw blade.

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