WO2015194567A1

WO2015194567A1 - Diamond wire saw

Info

Publication number: WO2015194567A1
Application number: PCT/JP2015/067358
Authority: WO
Inventors: キム，ヒョヨン; 谷本明良
Original assignee: キム，ヒョヨン; 株式会社ダイアテック
Priority date: 2014-06-16
Filing date: 2015-06-16
Publication date: 2015-12-23
Also published as: JP5831860B1; JP2016002615A

Abstract

Multiple beads (3) are arranged apart from each other on a wire rope (2). Each bead (3) is equipped with an annular diamond layer (4) disposed on the outer circumferential surface of a base (5). At least one first protruded part (41a) and at least one recessed part (41b) are formed on a first end face (41) of each diamond layer (4), said first end face (41) facing a first side, that is, one side in the longitudinal direction of the diamond wire saw (1). In a cross-section that includes the center axis (3a) of the bead (3) and passes through the at least one recessed part (41b), the first end face (41) inclines away from the first side from the inner edge (411) to the outer edge (412). The first end face (41) is formed into a smooth curved surface that connects the at least one protruded part (41a) with the at least one recessed part (41b). The base (5) is a coil that is produced by winding a thin metal wire into a spiral shape.

Description

Diamond wire saw

The present invention relates to a diamond wire saw.

Generally, concrete structures (for example, various buildings, bridges, highways, railway overpasses, dams, tunnels, chimneys, breakwaters, etc.) and steel members (for example, steel structures, reactor pressure vessels, etc.) A diamond wire saw is used to quickly cut a workpiece such as a stone.

FIG. 10 is a side view showing a conventional diamond wire saw (hereinafter simply referred to as “wire saw”) 900 (see, for example, Patent Document 1). The left side is shown as a cross-sectional view so that the internal structure can be understood. In the wire saw 900, beads 903 are provided at regular intervals on a wire rope 902 twisted with a steel wire. The beads 903 are obtained by integrating a diamond layer 904 having a cylindrical shape on an outer peripheral surface of a metal base 905 (sometimes referred to as a “base metal”) 905 having a cylindrical shape. The diamond layer 904 is made of, for example, a sintered material obtained by sintering a mixture of diamond abrasive grains and a binding material. A protector (protective layer) 907 is provided between the adjacent beads 903 of the wire saw 900. The protector 907 protects the wire rope 902 and fixes the beads 903. The wire saw 900 has a degree of flexibility (softness) that can be appropriately deformed according to the shape of the object to be cut. Patent Document 2 describes a wire saw in which movement of beads 903 is suppressed by embedding a coiled spring in a protector 907 between adjacent beads 903.

The wire saw 900 is connected at both ends so as to form a loop. The object to be cut is cut by running while pressing the loop of the wire saw 900 against the object to be cut.

Japanese Patent Laid-Open No. 9-234728 JP-A-9-225735

In cutting using a diamond wire saw, it is desired to cut an object to be cut in a shorter time (i.e., a high cutting speed) and to be able to use the diamond wire saw for a long period of time (i.e., a long life). .

An object of the present invention is to provide a diamond wire saw with improved cutting speed and life.

The diamond wire saw of the present invention comprises a wire rope, a plurality of beads that are penetrated by the wire rope and spaced apart from each other on the wire rope, and a protector that covers the wire rope between adjacent beads. Prepare. The beads include a cylindrical base and an annular diamond layer provided on the outer peripheral surface of the base. When one side in the longitudinal direction of the diamond wire saw is the first side and the other side is the second side, the first end surface of the diamond layer facing the first side faces the first side. At least one first convex portion that protrudes and at least one first concave portion that recedes away from the first side are formed. In a cross section including the central axis of the bead and passing through the at least one first recess, the first end surface is inclined so as to move away from the first side from the inner end edge toward the outer end edge. The first end surface is formed of a smooth curved surface connecting the at least one first convex portion and the at least one first concave portion. The base is a coil in which a thin metal wire is spirally wound.

According to the present invention, a wire saw with improved cutting speed and life can be provided.

FIG. 1 is a side view of a diamond wire saw according to an embodiment of the present invention. FIG. 2 is a side sectional view of a diamond wire saw according to an embodiment of the present invention. FIG. 3 is a side view showing only the beads and coil springs constituting the diamond wire saw according to one embodiment of the present invention. FIG. 4A is a perspective view of beads constituting a diamond wire saw according to an embodiment of the present invention, as viewed from the first end face side. FIG. 4B is a perspective view of the beads constituting the diamond wire saw according to the embodiment of the present invention, as viewed from the second end face side. FIG. 5A is a front view of beads constituting a diamond wire saw according to an embodiment of the present invention, viewed from the first end face side. FIG. 5B is a side view of the beads constituting the diamond wire saw according to the embodiment of the present invention as seen from the direction of the arrow 5B in FIG. 5A. FIG. 5C is a bottom view of the beads constituting the diamond wire saw according to the embodiment of the present invention as seen from the direction of the arrow 5C in FIG. 5B. 6A is a cross-sectional view of the bead taken along the vertical plane including the line 6A-6A in FIG. 5A. 6B is a cross-sectional view of the bead taken along the horizontal plane including the line 6B-6B in FIG. 5B. FIG. 7 is an exploded perspective view of the beads constituting the diamond wire saw according to the embodiment of the present invention, viewed from the first end face side. FIG. 8A is a side view of a diamond layer constituting a bead according to an embodiment of the present invention. FIG. 8B is a bottom view of a diamond layer constituting a bead according to an embodiment of the present invention. FIG. 9A is a vertical cross-sectional view of a bead according to another embodiment of the present invention. FIG. 9B is a vertical cross-sectional view of a bead according to still another embodiment of the present invention. FIG. 10 is a partial cross-sectional side view of a conventional diamond wire saw.

In order to improve the cutting speed in cutting using a wire saw, for example, (1) increase the traveling speed of the wire saw with respect to the object to be cut, (2) increase the tension applied to the wire saw, diamond (3) increase the number of beads per unit length of the wire saw (hereinafter referred to as “bead density”) (ie, decrease the bead pitch), etc. Can be considered.

However, according to the study by the present inventors, none of these methods has improved the cutting speed and life as expected.

In examining the reason why it is difficult for the conventional wire saw 900 (see FIG. 10) to improve the cutting speed and life, the present inventors pay attention to the mechanism by which the conventional wire saw 900 cuts the workpiece. did. In the cutting using the conventional wire saw 900, the beads 903 run on the workpiece. At this time, fine irregularities on the outer peripheral surface of the diamond layer 904 of the beads 903 scrape off the surface of the object to be cut. A large number of diamond layers 904 repeatedly cut the surface of the object to be cut, whereby the object to be cut is cut. This phenomenon is similar to “grinding” using a grindstone.

For example, in grinding using a rotating grindstone, it is known that when the rotational speed of the grindstone is increased, heat generation increases, which wears the abrasive grains of the grindstone and shortens the life of the grindstone. In addition, it is known that when the cutting amount is increased in grinding using a rotating grindstone, the abrasive grains of the grindstone fall off, which shortens the grindstone life.

The diamond layer 904 of the conventional wire saw 900 can be considered as a grinding wheel in grinding. Therefore, in the cutting using the conventional wire saw 900, the method of increasing the traveling speed of the wire saw 900 or increasing the pressing force of the diamond layer 904 cannot improve the cutting speed but also increases heat generation. In addition, the life of the wire saw 900 is shortened.

Grinding is originally a processing method with a small amount of cut. As long as the cutting with the wire saw 900 mainly uses grinding, it is difficult to dramatically improve the cutting speed while ensuring the life.

Further, in the conventional wire saw 900 (see FIG. 10), the bead 903 including the base 905 and the diamond layer 904 is hard and can be regarded as a rigid body, and is not substantially deformed. Therefore, the flexibility of the wire saw 900 is ensured by the portion between the adjacent beads 903. When the density of the beads 903 is increased, the distance between the adjacent beads 903 is reduced, so that the flexibility of the wire saw 900 is lowered. This makes it difficult for the wire saw 900 to be appropriately deformed according to the shape of the workpiece, and reduces the adhesion between the diamond layer 904 and the workpiece. For this reason, in the conventional wire saw 900, the density of the beads 903 has an upper limit, which makes it difficult to improve the cutting speed.

If the length of the beads 903 (that is, the length Lb of the base 905 along the longitudinal direction of the wire saw 900) is shortened, the density of the beads 903 is increased while ensuring the flexibility of the wire saw 900. Can do. However, in this case, it is necessary to shorten the length L of the diamond layer 904 that contributes to cutting. Therefore, since the improvement in the cutting speed due to the increase in the density of the beads 903 is canceled out by the reduction in the length of the diamond layer 904, it is difficult to improve the cutting speed.

Through the above studies, the present inventors have reached a conclusion that it is difficult to improve both the cutting speed and the life as long as the wire saw cuts the workpiece mainly using grinding. . In addition, as long as the conventional beads 903 are used, it is difficult to increase the bead density while securing the flexibility of the wire saw, and thus it is difficult to improve the cutting speed by increasing the bead density. The conclusion has been reached.

From these viewpoints, the present inventors have found a novel bead that can cut a workpiece by utilizing a phenomenon different from grinding and can increase the bead density, thereby completing the present invention. It came to do.

That is, the diamond wire saw of the present invention includes a wire rope, a plurality of beads penetrating the wire rope and spaced apart from each other on the wire rope, and a protector that covers the wire rope between adjacent beads. With. The beads include a cylindrical base and an annular diamond layer provided on the outer peripheral surface of the base. When one side in the longitudinal direction of the diamond wire saw is the first side and the other side is the second side, the first end surface of the diamond layer facing the first side faces the first side. At least one first convex portion that protrudes and at least one first concave portion that recedes away from the first side are formed. In a cross section including the central axis of the bead and passing through the at least one first recess, the first end surface is inclined so as to move away from the first side from the inner end edge toward the outer end edge. The first end surface is formed of a smooth curved surface connecting the at least one first convex portion and the at least one first concave portion. The base is a coil in which a thin metal wire is spirally wound.

According to the present invention, the first end surface of the diamond layer is formed of a smooth curved surface having at least one first convex portion and at least one first concave portion. For this reason, when the first end face collides with the workpiece, the first end face “cuts” the surface of the workpiece. Chips generated by cutting are discharged to the outside in the radial direction by the inclined first recess. Thus, since the diamond wire saw of the present invention is cut by cutting an object to be cut, the cutting speed and life are improved.

Also, since the base of the bead is made of a coil, the base itself can be bent and deformed. For this reason, bead pitch can be shortened and bead density can be improved, ensuring the flexibility of a diamond wire saw. Thereby, the cutting speed is further improved.

As a result, according to the present invention, it is possible to provide a wire saw with improved cutting speed and life.

In the diamond wire saw of the present invention, it is preferable that circumferential positions of the at least one first convex portion and the at least one first concave portion are different between adjacent beads. According to such a preferred embodiment, since the position on the diamond layer where the object to be cut collides can be made different for each bead, the cutting speed can be further improved.

In the diamond wire saw of the present invention described above, the second end surface facing the second side of the diamond layer has at least one second convex portion protruding toward the second side, and from the second side. At least one second recess that is recessed so as to move away may be formed. In this case, in a cross section including the central axis of the bead and passing through the at least one second recess, the second end surface is inclined so as to be away from the second side as it goes from the inner edge to the outer edge. It is preferable. The second end surface is preferably formed of a smooth curved surface connecting the at least one second convex portion and the at least one second concave portion. It is preferable that the at least one second convex portion of the second end surface is disposed at the same position in the circumferential direction as the at least one first concave portion of the first end surface. It is preferable that the at least one second concave portion of the second end surface is disposed at the same position in the circumferential direction as the at least one first convex portion of the first end surface. According to such a preferred embodiment, even when a rotational motion for preventing wear of the diamond wire saw is given, a uniform cutting ability can be obtained.

In the above-described diamond wire saw according to the present invention, it is preferable that the at least one first convex portion of the diamond layer is located at substantially the same position as the end portion on the first side of the base in the central axis direction. . Further, it is preferable that the at least one second convex portion of the diamond layer is located at substantially the same position as the end portion on the second side of the base in the central axis direction. According to such a preferred embodiment, since the length of the base can be shortened, the cutting speed is further improved by increasing the bead density or by improving the flexibility of the diamond wire saw. .

In the diamond wire saw of the present invention described above, it is preferable that the protector is made of a material that is more easily compressed and deformed than the diamond layer. According to such a preferred embodiment, the protector is compressively deformed in the radial direction, so that chips generated by the diamond layer cutting the workpiece can be easily discharged. This is advantageous for improving the cutting speed.

In the diamond wire saw of the present invention described above, the outer diameter of the protector adjacent to the diamond layer is preferably the same as the outer diameter of the diamond layer. According to such a preferred embodiment, during the cutting, the diamond layer collides with the object to be cut and the diamond wire saw jumps from the object to be cut, or the diamond layer breaks due to the diamond layer being caught on the object to be cut or the wire The possibility that the rope breaks can be reduced.

In the above-described diamond wire saw of the present invention, it is preferable that the fine metal wires constituting the base are wound so that adjacent fine metal wires are in contact with each other. According to such a preferred embodiment, the diamond layer can be easily formed on the base.

In the diamond wire saw of the present invention described above, the outer peripheral surface of the diamond layer is preferably a cylindrical surface coaxial with the central axis. According to such a preferred embodiment, the rotation of the diamond wire saw is facilitated at the time of cutting, and the cutting amount of the diamond layer with respect to the object to be cut at the time of rotation is stabilized, so that the cutting speed is further improved.

Hereinafter, the present invention will be described in detail while showing preferred embodiments. However, it goes without saying that the present invention is not limited to the following embodiments. For convenience of explanation, the drawings referred to in the following description show only the main members necessary for explaining the present invention in a simplified manner among the constituent members of the embodiment of the present invention. Therefore, the present invention can include any member not shown in the following drawings.

FIG. 1 is a side view of a diamond wire saw (hereinafter simply referred to as “wire saw”) 1 according to an embodiment of the present invention. FIG. 2 is a side sectional view of the wire saw 1. In FIG. 2, the central wire rope 2 is shown as a side view, not a cross-sectional view. 1 and 2, an arrow A indicates a traveling direction of the wire saw 1 with respect to an object to be cut (that is, an object to be cut, not shown). For convenience of the following explanation, the side in the traveling direction A of the wire saw 1 (left side in FIGS. 1 and 2) is referred to as “front side” or “first side”, and is opposite to the traveling direction A of the wire saw 1. The right side in FIGS. 1 and 2 is referred to as “rear side” or “second side”. The dimension along the longitudinal direction of the wire saw 1 is referred to as “length”.

1 and 2, the wire saw 1 includes a wire rope 2 as a core. The wire rope 2 holds the beads 3 and moves (runs) while bringing the beads 3 into contact with an object to be cut. Although there is no restriction | limiting, the wire rope 2 can use what was produced by twisting several steel wires. The outer diameter and strength (for example, breaking strength) of the wire rope 2 can be appropriately changed according to the object to be cut and cutting conditions. The wire rope 2 has flexibility (or flexibility) so that it can be deformed according to the shape of the object to be cut.

The wire rope 2 passes through the beads 3 and the coil spring 6. FIG. 3 is a side view showing only the beads 3 and the coil springs 6 extracted from the wire saw 1. The beads 3 and the coil springs 6 are alternately arranged along the longitudinal direction of the wire saw 1. Adjacent beads 3 and coil spring 6 are in contact with each other.

FIG. 4A is a perspective view of the bead 3 viewed from the front side (first side). FIG. 4B is a perspective view of the bead 3 as seen from the back side (second side). FIG. 5A is a front view of the bead 3 viewed from the front side (first side). FIG. 5B is a side view of the bead 3 as seen from the direction of the arrow 5B in FIG. 5A. FIG. 5C is a bottom view of the bead 3 as seen from the direction of the arrow 5C in FIG. 5B. 6A is a cross-sectional view of the bead 3 taken along the vertical plane including the line 6A-6A in FIG. 5A. 6B is a cross-sectional view of the bead 3 taken along the horizontal plane including the line 6B-6B in FIG. 5B. 6A and 6B, the alternate long and short dash line 3a is the central axis of the bead 3. The beads 3 are penetrated by the wire lobe 2 so as to be coaxial with the wire rope 2. FIG. 7 is an exploded perspective view of the bead 3 viewed from the front side (first side). As shown in these figures, the bead 3 includes a diamond layer 4 and a base 5. In the following description, a direction along a straight line orthogonal to the central axis 3a is referred to as “radial direction”, and a direction rotating around the central axis 3a is referred to as “circumferential direction”. In the radial direction, the side far from the central axis 3a is called “outer side”, and the side near the central axis 3a is called “inside”.

The diamond layer 4 moves (runs) relative to the workpiece while being in contact with the workpiece, and cuts the workpiece. In order to improve the strength and wear resistance of the diamond layer 4, the diamond layer 4 contains diamond particles as superabrasive grains.

The diamond layer 4 has an annular shape continuous around the central axis 3a. The outer peripheral surface (surface opposite to the central axis 3a) 45 of the diamond layer 4 is a cylindrical surface coaxial with the central axis 3a. The diamond layer 4 has a first end face 41 and a second end face 42 at both ends in the direction of the central axis 3a. The first end surface 41 is an end surface facing the front side (first side) in the traveling direction A, and the second end surface 42 is an end surface facing the rear side (second side) in the traveling direction A.

FIG. 8A is a side view of the diamond layer 4, and FIG. 8B is a bottom view of the diamond layer 4.

The shape of the first end face 41 of the diamond layer 4 will be described.

As shown in FIG. 4A, FIG. 5B, FIG. 7 and FIG. 8A, the first end face 41 has two first protrusions 41a protruding toward the front side (first side) and the front side (first side). Two first recesses 41b are formed so as to recede from the first side. The two first convex portions 41a are arranged at symmetrical positions with respect to the central axis 3a. The two first concave portions 41b are also arranged at symmetrical positions with respect to the central axis 3a. The direction connecting the two first convex portions 41a and the direction connecting the two first concave portions 41b are orthogonal to each other on the central axis 3a. Reference numeral 411 denotes an inner edge of the first end surface 41, and reference numeral 412 denotes an outer edge of the first end surface 41.

As shown in FIG. 6A, in a cross section including the central axis 3a and passing through the two first convex portions 41a, the first end face 41 is along the radial direction (that is, a straight line orthogonal to the central axis 3a). Yes.

As shown in FIG. 6B, in the cross section including the central axis 3a and passing through the two first recesses 41b, the first end face 41 is located on the front side (first side) from the inner end edge 411 to the outer end edge 412. Inclined away from the side.

Although illustration is omitted, the inclination of the first end face 41 in the cross section along the plane including the central axis 3a between the first convex portion 41a and the first concave portion 41b is changed from the state of FIG. 6A to the state of FIG. 6B. It is gradually changing.

Thus, the position of the first end surface 41 in the direction of the central axis 3a differs between the first convex portion 41a and the first concave portion 41b. Further, in the cross section along the plane including the central axis 3a, the inclination of the first end face 41 is different from that of the first convex portion 41a and the first concave portion 41b. The 1st end surface 41 is comprised by the smooth curved surface which connects such a 1st convex part 41a and the 1st recessed part 41b.

The shape of the second end face 42 of the diamond layer 4 will be described.

As shown in FIGS. 4B, 5C, and 8B, the second end face 42 includes two second convex portions 42a that protrude toward the rear side (second side), and the rear side (second side). Two second recesses 42b that are receded away from the side) are formed. The two second convex portions 42a are arranged at symmetrical positions with respect to the central axis 3a. The two second recesses 42b are also arranged at symmetrical positions with respect to the central axis 3a. The direction connecting the two second convex portions 42a and the direction connecting the two second concave portions 42b are orthogonal to each other on the central axis 3a. Reference numeral 421 denotes an inner edge of the second end surface 42, and reference numeral 422 denotes an outer edge of the second end surface 42.

As shown in FIG. 6B, in a cross section including the central axis 3a and passing through the two second convex portions 42a, the second end face 42 is along the radial direction (that is, a straight line orthogonal to the central axis 3a). Yes.

As shown in FIG. 6A, in the cross section including the central axis 3a and passing through the two second recesses 42b, the second end face 42 is rearward (second Inclined away from the side.

Although illustration is omitted, the inclination of the second end face 42 in the cross section along the plane including the central axis 3a between the second convex portion 42a and the second concave portion 42b changes from the state of FIG. 6B to the state of FIG. 6A. It is gradually changing.

Thus, the position of the second end face 42 in the direction of the central axis 3a differs between the second convex part 42a and the second concave part 42b. Further, in the cross section along the plane including the central axis 3a, the inclination of the second end face 42 is different from that of the second convex portion 42a and the second concave portion 42b. The 2nd end surface 42 is comprised by the smooth curved surface which connects such a 2nd convex part 42a and the 2nd recessed part 42b.

The 2nd convex part 42a of the 2nd end face 42 is arranged in the same position in the peripheral direction as the 1st crevice 41b of the 1st end face 41. The 2nd recessed part 42b of the 2nd end surface 42 is arrange | positioned in the same position in the circumferential direction as the 1st convex part 41a of the 1st end surface 41. FIG. The dimension (namely, length of the outer peripheral surface 45) L1 (refer FIG. 5B) of the outer peripheral surface 45 of the diamond layer 4 along the direction of the central axis 3a is constant irrespective of the position in the circumferential direction. The diamond layer 4 is annularly continuous around the central axis 3a while the position in the direction of the central axis 3a changes periodically. The diamond layer 4 has a two-fold rotationally symmetric shape with respect to the center axis 3a (a shape that matches the shape before rotation when rotated 180 degrees around the center axis 3a). The diamond layer 4 has the same shape even if the front and rear are reversed.

As shown in FIG. 4A, FIG. 4B, FIG. 6A, FIG. 6B, and FIG. 7, the base 5 is formed by winding a metal thin wire (wire) in a coil shape, and has a hollow cylindrical shape as a whole. have. The material of the thin wire is not limited, but, for example, steel can be used. For example, spring steel wires such as spring stainless steel wires and piano steel wires can be used. The thickness of the thin line is not limited, but is preferably 0.5 to 1.3 mm. In a preferred embodiment, the thin wires constituting the base 5 are wound in a coil shape with the thin wires adjacent to each other in the direction of the central axis 3a contacting each other as shown in FIGS. 6A and 6B. This facilitates the formation of the diamond layer 4 on the base 5. However, the present invention is not limited to this, and fine wires adjacent in the direction of the central axis 3a may be separated from each other and wound in a coil shape.

The dimension of the base 5 in the direction of the central axis 3a (that is, the length of the base 5) Lb (see FIG. 5B) is not limited, but in the present embodiment, the dimension of the diamond layer 4 in the direction of the central axis 3a (that is, The length of the diamond layer 4 is almost the same as L (see FIG. 5B). The front end (first side) end of the base 5 is located at substantially the same position as the first convex portion 41a of the first end face 41 of the diamond layer 4 in the direction of the central axis 3a. Further, the rear side (second side) end portion of the base 5 is positioned substantially at the same position as the second convex portion 42a of the second end face 42 of the diamond layer 4 in the direction of the central axis 3a. That is, the length Lb of the base 5 is set to the minimum length necessary for mounting the diamond layer 4. Thereby, when the density of the beads 3 is the same as the conventional one, the length between the adjacent beads 3 can be increased, so that the flexibility of the wire saw 1 can be improved. Alternatively, when the length between adjacent beads 3 is the same as the conventional one, the density of the beads 3 can be increased. These are all advantageous for improving the cutting speed of the wire saw 1.

However, the base 5 may protrude from the diamond layer 4 toward the front side and / or the rear side. Since the base 5 is composed of a coil, the base 5 itself can be elastically bent and deformed. That is, unlike the conventional bead 903, the bead 3 of the present invention itself can have flexibility. Therefore, even if the base 5 is longer than the diamond layer 4, the flexibility of the wire saw 1 can be ensured.

The diamond layer 4 described above is provided on the outer peripheral surface of the base 5. There is no restriction | limiting in the formation method of the diamond layer 4, For example, arbitrary methods, such as sintering, brazing, and electrodeposition, can be used. In the sintering method, a material containing diamond particles is molded into a predetermined shape on the base 5 and fired. In the brazing method, diamond particles are fixed on the base 5 using a metal bonding material (for example, nickel). In the electrodeposition method, diamond particles are fixed simultaneously when a plating layer is formed on the base 5. The method of forming the diamond layer 4 can be changed according to, for example, the material of the object to be cut. The shape and particle size of the diamond particles contained in the diamond layer 4 can be changed according to, for example, the method of forming the diamond layer 4. The diamond layer 4 can include particles such as CBN (cubic boron nitride) in addition to diamond particles.

2 and 3, a coil spring 6 is provided between the adjacent beads 3. The coil spring 6 has functions such as maintaining a constant distance between the beads 3, mitigating the impact that the beads 3 receive from the workpiece during cutting, and protecting the wire rope 2 from the workpiece. The coil spring 6 is formed by winding a thin metal wire (wire) in a coil shape, and has a hollow cylindrical shape as a whole. The material of the thin wire is not limited, but, for example, steel can be used. For example, the coil spring 6 having the same inner diameter and outer diameter as the base material 5 can be produced using the same thin wire as the base 5. As shown in FIG. 2 and FIG. 3, the fine wires constituting the coil spring 6 are preferably wound in a coil shape with the fine wires adjacent to each other in the longitudinal direction of the wire saw 1 being separated from each other. This is advantageous for improving the flexibility of the wire saw 1. In the present invention, the coil spring 6 can be omitted.

The wire rope 2 is inserted into the beads 3 and the coil spring 6 so that they are alternately arranged. At this time, it is preferable that the position of the 1st convex part 41a and the circumferential direction of the 1st recessed part 41b differs between the adjacent beads 3, Furthermore, as shown in FIG. It is preferable that the circumferential positions of the first convex portion 41a and the first concave portion 41b are different by 90 degrees. This is advantageous in improving the cutting speed because the position on the diamond layer 4 where the object to be cut collides can be made different for each bead 3. Such a configuration in which the positions in the circumferential direction of the diamond layer 4 are different between adjacent beads 3 can be realized, for example, by inverting the direction of the front and rear direction of every other bead 3. Alternatively, it can be realized by rotating every other bead 3 around the wire rope 2 by 90 degrees.

As shown in FIGS. 1 and 2, a protector 7 is provided in a portion between adjacent beads 3. The protector 7 has functions such as covering and protecting the wire rope 2, coil spring 6, and base 5, and maintaining a constant distance between the beads 3. The outer peripheral surface 45 of the diamond layer 4 is not covered with the protector 7 and is exposed to the outside. In a preferred embodiment, the protector 7 is made of a material that is more easily compressed and deformed than the diamond layer 4. For example, an elastic resin can be used as the material of the protector 7. Specifically, natural rubber, synthetic rubber, silicone rubber, urethane, thermosetting elastomer, and thermoplastic elastomer can be used. Since the protector 7 has compressibility, the protector 7 can be appropriately compressed and deformed at the time of cutting.

The protector 7 can be created by molding (for example, injection molding) the resin material into a predetermined shape in a mold. 1 and 2, the recess 7a formed on the outer surface of the protector 7 is a jig provided in the mold for holding the coil spring 6 and the wire rope 2 in a predetermined position when the protector 7 is molded. It is a trace of. Depending on the molding method of the protector 7, the recess 7a can be omitted.

The cross-sectional shape orthogonal to the longitudinal direction of the wire saw 1 on the outer peripheral surface of the protector 7 is arbitrary, but in a preferred embodiment, it is circular (except for the recess 7a). The outer diameter of the protector 7 is not limited, but is preferably equal to or smaller than the outer diameter of the diamond layer 4. If the outer diameter of the protector 7 is too small compared to the outer diameter of the diamond layer 4, the diamond layer 4 that protrudes outward relative to the protector 7 at the time of cutting collides with the workpiece, and the wire saw 1. Jumps from the object to be cut (this phenomenon is called “hammering”), and the diamond layer 4 is caught by the object to be cut, and the diamond layer 4 is broken or the wire rope 2 is broken. Therefore, it is preferable that the outer diameter difference between the protector 7 and the diamond layer 4 is small, and the protector 7 (at least a portion adjacent to the diamond layer 4 of the protector 7) has the same outer diameter as the diamond layer 4. preferable. In particular, the first end face 41 (and further the second end face 42) of the diamond layer 4 is preferably covered with the protector 7.

In FIG. 1 and FIG. 2, the outer diameter of the protector 7 is the smallest in the central portion of the adjacent diamond layer 4, and becomes larger as the diamond layer 4 is approached, and the diamond layer 4 is adjacent to the diamond layer 4. It is almost the same as the outer diameter. However, the present invention is not limited to this. For example, the outer diameter of the protector 7 may be constant in the longitudinal direction of the wire saw 1.

Prior to cutting the object to be cut, the wire saw 1 is cut to a predetermined length, and both ends thereof are connected to form a loop of the endless wire saw 1. At this time, both ends of the wire saw 1 are connected in a state where one end of the wire saw 1 is rotated (twisted) in the twisting direction of the wire rope 2 with respect to the other end. The loop of the wire saw 1 in the state in which the wire saw 1 is twisted in this way, when cutting the object to be cut, runs in the direction of the arrow A along the longitudinal direction with respect to the object to be cut, and at the same time the arrow R (See FIG. 1). Thereby, the one-side abrasion of the diamond layer 4 and the protector 7 can be prevented. Moreover, the cutting function of the diamond layer 4 mentioned later can be expressed effectively.

The loop-shaped wire saw 1 is circulated by a cutting device. The wire saw 1 of the present invention is a tensile cutting method in which an object to be cut is placed in a loop of the wire saw 1 and tension is applied to the wire saw 1 to cut the object to be cut. The present invention can be applied to any of the cutting methods in which the wire saw 1 placed outside and stretched between pulleys is pressed against the object to be cut to cut the object to be cut.

The wire saw 1 of the present invention can drastically improve the cutting speed and life compared to the conventional wire saw 900 (see FIG. 10). The present inventors consider the reason as follows.

The first reason is related to the shape of the diamond layer 4. In the present invention, the first end surface 41 on the front side in the traveling direction A of the diamond layer 4 is formed of a smooth three-dimensional curved surface including a first convex portion 41a and a first concave portion 41b. In FIG. 4A and FIG. 5C, the case where the 1st end surface 41 collided with the to-be-cut | disconnected object in the 1st convex part 41a is considered, for example. As described above, the wire saw 1 rotates while traveling in the traveling direction A with respect to the workpiece (arrow R in FIG. 1). Therefore, as time passes, the collision position between the first end face 41 and the object to be cut gradually moves from the first convex portion 41a toward the first concave portion 41b. The smooth curved surface extending from the first convex portion 41a to the first concave portion 41b of the first end surface 41 functions in the same manner as, for example, a spiral cutting edge of a drill to “cut” the workpiece. Chips generated by cutting the workpiece at the first end face 41 are guided along the first end face 41 toward the first recess 41b. In the first recess 41b, the first end surface 41 is inclined so that the outer end edge 412 is located on the rear side as compared with the inner end edge 411, as shown in FIG. 6B. Therefore, the chips are discharged to the outside in the radial direction at the first recess 41b or before reaching the first recess 41b. If necessary, the protector 7 is compressed and deformed in the radial direction to form a chip discharge path.

In contrast, in the conventional wire saw 900 (see FIG. 10), the diamond layer 904 has a simple cylindrical shape. The front end surface of the diamond layer 904 in the traveling direction is an annular plane perpendicular to the longitudinal direction of the wire saw 900. Therefore, even when the wire saw 900 rotates with respect to the workpiece during cutting, the front end surface of the diamond layer 904 does not exhibit the same cutting function as the spiral cutting edge of the drill. . Further, even if the front end face of the diamond layer 904 “cuts” the workpiece, the chips generated by the cutting continue to be held on the front end face and are not easily discharged. Therefore, the cutting function is not fully exhibited.

Thus, the wire saw 1 of the present invention can “cut” the workpiece with the diamond layer 4 by utilizing the fact that the wire saw 1 rotates during cutting. In general, “cutting” has a larger cutting depth than “grinding”. Therefore, the wire saw 1 of the present invention can greatly improve the cutting speed as compared with the conventional wire saw 900.

Since “cutting” has a larger cutting depth than “grinding”, the relative speed of the cutting tool (for example, cutting blade in cutting, rotating grindstone in grinding) is set to be low, and the workpiece is also cut. The contact area between the blade and the blade is small. Therefore, in “cutting”, heat generation is relatively small. Similarly to this, the wire saw 1 of the present invention suppresses heat generation during cutting as compared with the conventional wire saw 900. This reduces the wear of the diamond layer 4 and is advantageous for extending the life of the wire saw 1. Further, since the cooling water is not necessary at the time of cutting, the possibility of treating the used radioactively contaminated cooling water as a problem, for example, when cutting the reactor pressure vessel can be reduced.

The wire saw 1 of the present invention can increase the cutting speed even when the relative speed (feed speed) of the wire saw with respect to the workpiece is lower than that of the conventional wire saw 900. Further, by increasing the tension applied to the wire saw 1 and increasing the pressing force of the diamond layer 4 against the workpiece, the cutting amount can be increased and the cutting speed can be increased.

In the conventional wire saw 900 (see FIG. 10), the end face on the front side in the running direction of the diamond layer 904 is a plane perpendicular to the running direction, so that the end face is easily caught on the workpiece. For this reason, the hammering which jumps away so that the wire saw 900 may leave | separate from a to-be-cut object may be produced, and this may reduce a cutting speed. Alternatively, the diamond layer 904 may be missing, which can reduce the life of the wire saw 900. In the wire saw 1 of the present invention, the first end surface 41 on the front side in the traveling direction A of the diamond layer 4 is formed of a smooth three-dimensional curved surface including the first convex portion 41a and the first concave portion 41b. Combined with the rotation of the saw 1, the first end face 41 is not easily caught on the workpiece. Also in this respect, the wire saw 1 of the present invention is advantageous with respect to cutting speed and life.

A large amount of chips generated when the diamond layer 4 “cuts” the object to be cut is satisfactorily discharged because the first recess 41b of the first end face 41 is inclined as shown in FIG. 6B. Is done. This is advantageous in improving the cutting speed and extending the life of the diamond layer 4 as a “blade”.

At the time of cutting, the protector 7 can be compressed and deformed in the radial direction by an object to be cut or chips. Therefore, even when the protector 7 substantially covers the first end face 41 at the normal time when it is not cut, the protector 7 does not interfere with the “cutting” function of the first end face 41 and the chip discharging function. Rather, as described above, the small difference in the outer diameter between the protector 7 and the diamond layer 4 makes it possible to strongly press the diamond layer 4 against the workpiece while preventing hammering. It is advantageous for improvement.

The diamond layer 4 of the present invention has an outer peripheral surface 45 having a cylindrical surface shape, like the conventional diamond layer 904. The outer peripheral surface 45 scrapes off the surface of the workpiece. In this respect, it can be considered that the diamond layer 4 of the present invention “grinds” the object to be cut, like the conventional diamond layer 904. However, the contribution of “grinding” to the cutting of the workpiece is much smaller than the contribution of “cutting”. Accordingly, even if the length L1 (see FIG. 5B) of the outer peripheral surface 45 of the diamond layer 4 to be “ground” is reduced, this has a small effect on reducing the cutting speed. Rather, the length L1 of the outer peripheral surface 45 of the diamond layer 4 is reduced to increase the density of the beads 3 (in other words, the pitch of the beads 3 is reduced), whereby the diamond layer 4 to be “cut” is cut. If the number is increased, the cutting speed can be further improved.

The length L1 of the outer peripheral surface 45 of the diamond layer 4 of the present invention is not limited, but is preferably 3 mm to 5 mm. This is extremely short considering that the general length L of the conventional diamond layer 904 is about 6.0 mm to 6.5 mm.

The second reason is related to the fact that the base 5 of the bead 3 is a coil in which a thin metal wire is spirally wound. The base 5 is indispensable for efficiently creating the annular diamond layer 4. In the present invention, since the base 5 is a coil, the base 5 itself can be elastically bent and deformed. As shown in FIGS. 4A and 5B, the first end surface 41 of the diamond layer 4 of the present invention is formed with a first convex portion 41a and a first concave portion 41b. Therefore, even if the front side (first side) end of the base 5 is disposed at substantially the same position as the first convex portion 41a of the first end face 41 in the direction of the central axis 3a, the outer peripheral surface of the base 5 A part is exposed without being covered with the diamond layer 4. The portion of the base 5 that is not covered with the diamond layer 4 on the front side of the diamond layer 4 is particularly easily bent and deformed. Similarly, in the preferred embodiment described above, as shown in FIGS. 4B and 5C, the second end surface 42 of the diamond layer 4 is also formed with the second convex portion 42 a and the second concave portion 42 b. Therefore, the portion of the base 5 that is behind the diamond layer 4 and not covered with the diamond layer 4 is also particularly easily bent and deformed.

On the other hand, in the conventional wire saw 900 (see FIG. 10), the base 905 is a metal cylindrical object, and thus can be regarded as a substantially rigid body. Since the base 905 is not substantially deformed, it is necessary to increase the distance between the adjacent beads 903 in order to ensure the flexibility of the wire saw 900. Therefore, in the conventional wire saw 900, the upper limit of the density of the beads 903 is about 40 to 50 pieces / m. Since the density of the beads 903 cannot be increased, it is difficult to improve the cutting speed.

In the present invention, the base 5 itself constituting the beads 3 can be bent and deformed. For this reason, if it is sufficient to ensure the same degree of flexibility as the conventional wire saw 900, the distance between the adjacent beads 3 can be reduced in the present invention. Therefore, in the present invention, the density of the beads 3 can be 50 pieces / m or more, further 60 pieces / m or more, particularly 70 pieces / m or more. Thus, since the wire saw 1 of the present invention can increase the density of the beads 3, the cutting speed can be improved as compared with the conventional wire saw 900. As described above, unlike the conventional diamond layer 904, the diamond layer 4 of the present invention “cuts” an object to be cut. Therefore, the contribution of the increase rate of the bead density to the improvement of the cutting speed is much greater in the present invention than in the past.

Moreover, when the distance between the adjacent beads 3 is set to the same level as the conventional one, the flexibility of the wire saw 1 is improved. This is advantageous in improving the adhesion between the diamond layer 4 and the object to be cut during cutting. Therefore, also in this case, the wire saw 1 of the present invention can improve the cutting speed as compared with the conventional wire saw 900.

For example, in the conventional wire saw 900 (see FIG. 10), the diamond layer 904 has a length L of 6.5 mm and an outer diameter D of 11 mm. The length Lb of the base 905 is 10 to 12 mm. The density of the beads 903 is 50 pieces / m or less. On the other hand, in the wire saw 1 of the present invention (see FIG. 5B), the diamond layer 4 has a length L of 6.5 mm, a length L1 of the outer peripheral surface 45 of 3.5 mm, and an outer diameter D of 11 mm. . The length Lb of the base 5 is 6.5 mm. In this case, in order to ensure the same degree of flexibility as the conventional wire saw 900, the density of the beads 3 can be increased to about 67 pieces / m.

The above embodiment is merely an example. The present invention is not limited to the above embodiment, and can be modified as appropriate.

The shape of the first end face 41 is not limited to the above embodiment. For example, as shown in FIG. 6A, the first end face 41 does not need to be along the radial direction in a cross section including the central axis 3a and passing through the first convex portion 41a. For example, as shown in FIG. 9A, in the cross section including the central axis 3a and passing through the first convex portion 41a, the first end surface 41 has the outer edge 412 on the front side (first side) from the inner edge 411. You may incline so that it may be located in. Alternatively, as shown in FIG. 9B, in the cross section including the central axis 3a and passing through the first convex portion 41a, the first end surface 41 has the outer end edge 412 on the rear side (second side) than the inner end edge 411. ) May be inclined so as to be located. In FIG. 9B, the inclination angle of the first end surface 41 at the first convex portion 41a may be the same as the inclination angle of the first end surface 41 at the first concave portion 41b (see FIG. 6B), or from this. It can be large or small.

9A and 9B, an angle formed by the first end surface 41 with respect to a straight line that passes through the outer edge 412 of the first end surface 41 and is orthogonal to the central axis 3a is referred to as a “rake angle θ”. The rake angle θ is positive or negative when the first end face 41 is inclined so that the inner end edge 411 is positioned rearward (second side) from the outer end edge 412 as shown in FIG. 9A. Defined in The rake angle θ of the first end face 41 at the first convex portion 41a can be appropriately changed according to, for example, the material of the workpiece. For example, when cutting a sticky and low hardness material such as wood or plastic, the rake angle θ preferably takes a positive value (see FIG. 9A), such as carbon steel or cast iron. When cutting a brittle and high hardness material, the rake angle θ preferably takes a negative value (see FIG. 9B).

The shape of the second end face 42 of the diamond layer 4 is not limited to the above embodiment (see FIG. 4B). For example, it may be a plane orthogonal to the central axis 3a, like the end face on the back side of the conventional diamond layer 904. However, it is preferable that the second end face 42 has a three-dimensional curved surface as in the above-described embodiment, for example, in the following points. First, it is possible to configure beads whose front-rear direction is not required. As a result, as shown in FIG. 3, the first convex portion 41a is formed between the adjacent beads 3 only by reversing the front and back of every other single type of beads 3 and attaching them to the wire rope 2. And the position of the 1st recessed part 41b can be easily varied in the circumferential direction. Alternatively, the above-described wire saw 1 can be created by attaching the beads 3 to the wire rope 2 without considering the front-rear direction. Secondly, on the back side (second side) from the diamond layer 4, as described above, a region that can be easily bent and deformed can be formed on the base 5, so that the cutting speed can be improved.

The number of the first convex portions 41a and the first concave portions 41b provided on the first end surface 41 of the diamond layer 4 and the number of the second convex portions 42a and the second concave portions 42b provided on the second end surface 42 are as described above. There is no need to have two each as in the form, and there may be one, or three or more. However, the number of convex portions and concave portions provided on the same end face is preferably the same. Moreover, it is preferable that the convex portions and the concave portions are alternately arranged in the circumferential direction and at equal angular intervals with respect to the central axis 3a.

The effect of the wire saw of the present invention on a conventional wire saw was confirmed by experiments. This will be described below.

As the wire saw of the present invention, the wire saw 1 shown in FIGS. 1 to 8B described above was used (hereinafter referred to as “Example”). A wire saw having the same configuration as that shown in FIG. 10 was used as a conventional wire saw (hereinafter referred to as “comparative example”). The diamond layers of Examples and Comparative Examples were formed on a base by a sintering method using diamond particles as superabrasive grains. Table 1 shows the dimensions and the like of each part of the wire saws of Examples and Comparative Examples. The alphabetical symbols assigned to the dimensions in Table 1 are shown in FIGS. 5B and 10.

The example has a higher bead density than the comparative example, but the flexibility of the wire saw was the same in the example and the comparative example.

The wire saws of the examples and comparative examples were cut to a length of 15 m. With one end of the wire saw rotated (twisted) with respect to the other end, both ends of the wire saw were connected to form an endless wire saw loop.

A diamond wire saw (model: WS-10E) manufactured by HILTI was used as a cutting device for circulatingly driving a loop-shaped wire saw. The maximum output of the drive motor provided in this cutting device was 11 kW.

As an object to be cut, a 0.6 m high unreinforced concrete columnar body having a square bottom with a side of 0.9 m was prepared. The concrete strength was 24 N / cm ² .

Using the wire saws of the examples and comparative examples, the above-mentioned object to be cut was cut in the horizontal direction at a position 50 mm from the upper end. The cutting was a tensile cutting method. A loop-shaped wire saw was laid over a plurality of guide pulleys. Tension was applied to the wire saw by adjusting the position of the guide pulley with an air cylinder. The force applied to the guide pulley by the air cylinder calculated from the air pressure of the air cylinder and the cylinder inner diameter was kept constant at 180 kgf (1.82 kN) during cutting in both the examples and the comparative examples. The current value of the drive motor of the cutting device at the time of cutting was kept constant at 40 A in both the example and the comparative example. The cutting was a non-feed water cutting (so-called dry cutting) in which no cooling water was supplied in any of the examples and comparative examples.

Using the loop-shaped wire saws of Examples and Comparative Examples, the workpieces were repeatedly cut until each wire saw reached the end of its life. The fact that the wire saw reached the end of its life was judged from the change in sound during cutting, the temperature of the wire saw, the degree of progress of cutting, and the like. The wire saws of Examples and Comparative Examples were evaluated from the following viewpoints.

(1) Feeding speed The feeding speed of the wire saw during cutting the workpiece (that is, the moving speed of the wire saw relative to the workpiece) was determined.

(2) Cutting speed The total cutting area (m ² ) and the total cutting time (h) from the start of cutting to the end of cutting due to the life of the wire saw were determined. Than this,
Cutting speed = total cutting area / cutting speed defined by the total cutting time (m ² / h) was calculated.

(3) Life The value obtained by dividing the total cutting area (m ² ) from the start of cutting until the end of cutting due to the life of the wire saw by the length of the wire saw (15 m),
Life = Life of wire saw defined by total cutting area / wire saw length (m ² / m) was calculated.

(4) Cutting temperature The temperature of the wire saw from the start of cutting to the end of cutting due to the life of the wire saw was measured, and the maximum temperature was taken as the cutting temperature. The temperature was measured using an infrared radiation thermometer AD-5611A manufactured by A & D Corporation.

Table 2 shows the results of Examples and Comparative Examples.

Comparing the example and the comparative example, although the tension applied to the wire saw by the air cylinder via the guide pulley and the current value of the drive motor are the same, the feed rate is smaller in the example than in the comparative example. It was. This means that the wire saw of the example has a higher cutting resistance to the workpiece than the wire saw of the comparative example. As described above, the diamond layer 4 of the wire saw 1 of the present invention “cuts” the workpiece. In general, “cutting” has a larger depth of cut than “grinding”, and therefore the machining resistance is large. The difference between the embodiment and the comparative example regarding the feed rate is considered to be caused by the wire saw of the embodiment being cut by “cutting” the workpiece. In the examples and comparative examples, the feed rate value has a width because the wire saw has a plurality of beads spaced at a constant pitch, and the composition of the workpiece is not uniform. This is because the feed rate fluctuated due to the above.

In the example, the cutting speed and life were improved and the cutting temperature was low as compared with the comparative example. This is also considered to be because the wire saw of the example is cut by “cutting” the workpiece. In general, since “cutting” has a larger cutting amount than “grinding”, in the embodiment, even if the feed speed of the wire saw is slow, the workpiece can be cut in a short time. “Cutting” is a processing method that generates less heat than “grinding”. For this reason, the example had a higher cutting speed and a lower cutting temperature than the comparative example. Furthermore, in the embodiment, the service life of the wire saw was extended due to the slow feed rate and the low cutting temperature.

As described above, it is confirmed that the wire saw of the present invention can cut an object to be cut in a short time (that is, has a high cutting speed) and has a long life compared to a conventional wire saw. It was done. Moreover, since the temperature rise at the time of a cutting | disconnection is small, the wire saw of this invention was also confirmed that the necessity for water-cooling a wire saw at the time of a cutting | disconnection is low.

The field of use of the present invention is not limited, and can be widely used in fields where conventional wire saws are used, fields where conventional wire saws are difficult to cut, and the like. In particular, the wire saw of the present invention has a high cutting speed, a long life, and a small temperature rise during cutting, so that it is difficult to work for a long time, such as dismantling work of a reactor containment vessel or a reactor pressure vessel, It can be preferably used for applications where dry cutting is desired. Of course, the wire saw of the present invention can also be used for water supply cutting (so-called wet cutting) in which cutting is performed while applying cooling water.

DESCRIPTION OF SYMBOLS 1 Diamond wire saw 2 Wire rope 3 Bead 3a Bead central axis 4 Diamond layer 41 1st end surface 41a 1st convex part 41b 1st recessed part 411 Inner edge 412 of 1st end surface Outer edge 42 of 1st end surface 2nd end surface 42a 2nd convex part 42b 2nd recessed part 421 The inner side edge 422 of a 2nd end surface The outer side edge 45 of a 2nd end surface 45 Outer peripheral surface 5 of a diamond layer 6 Coil spring 7 Protector

Claims

A diamond wire saw comprising: a wire rope; a plurality of beads penetrating through the wire rope and spaced apart from each other on the wire rope; and a protector for covering the wire rope between adjacent beads. ,
The beads include a cylindrical base and an annular diamond layer provided on the outer peripheral surface of the base,
When one side in the longitudinal direction of the diamond wire saw is the first side and the other side is the second side, the first end surface of the diamond layer facing the first side faces the first side. At least one first convex portion protruding and at least one first concave portion retracted away from the first side are formed,
In a cross-section including the central axis of the bead and passing through the at least one first recess, the first end surface is inclined so as to move away from the first side from the inner end edge toward the outer end edge;
The first end surface is configured by a smooth curved surface connecting the at least one first convex portion and the at least one first concave portion,
The diamond wire saw according to claim 1, wherein the base is a coil in which a fine metal wire is spirally wound.
The diamond wire saw according to claim 1, wherein circumferential positions of the at least one first convex portion and the at least one first concave portion are different between adjacent beads.
The second end surface of the diamond layer facing the second side has at least one second convex portion protruding toward the second side, and at least one second receding away from the second side. A recess is formed,
In a cross section including the central axis of the bead and passing through the at least one second recess, the second end surface is inclined so as to move away from the second side from the inner end edge toward the outer end edge;
The second end surface is constituted by a smooth curved surface connecting the at least one second convex portion and the at least one second concave portion,
The at least one second convex portion of the second end surface is arranged at the same position in the circumferential direction as the at least one first concave portion of the first end surface;
3. The diamond wire saw according to claim 1, wherein the at least one second concave portion of the second end face is disposed at the same position in the circumferential direction as the at least one first convex portion of the first end face.
The at least one first protrusion of the diamond layer is located at substantially the same position as the first side end of the base in the central axis direction,
The diamond wire saw according to any one of claims 1 to 3, wherein the at least one second convex portion of the diamond layer is located at substantially the same position as the second side end portion of the base in the central axis direction. .
The diamond wire saw according to any one of claims 1 to 4, wherein the protector is made of a material that is more easily compressed and deformed than the diamond layer.
The diamond wire saw according to any one of claims 1 to 5, wherein an outer diameter of a portion of the protector adjacent to the diamond layer is the same as an outer diameter of the diamond layer.
The diamond wire saw according to any one of claims 1 to 6, wherein the fine metal wires constituting the base are wound so that adjacent fine metal wires are in contact with each other.
The diamond wire saw according to any one of claims 1 to 7, wherein an outer peripheral surface of the diamond layer is a cylindrical surface coaxial with the central axis.