JP2017061009A - Cutting edge replaceable type cutting tool - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent such a situation that a cutting insert is displaced during fastening by making a clamp screw easy to flex while stabilizing pressing force of the cutting insert.SOLUTION: A cutting insert 3 having an insert body 3b is fitted to an insert fitting seat 2 of a tool body 1 while held with a clamp screw 4, a through hole 3e is formed in the insert body 3b, and the fitting seat 2 has a fitting reference hole 5 and a screw hole 6 formed on one fitting seal wall surface 2a and a conic receiving face 7a, eccentric with a center line L1 of the screw hole 6 toward a rear end side, formed on the other fitting seal wall surface 2b. The clamp screw 4 has a male screw part 4 formed at one end and a head part 4b formed at the other end, a cylindrical part 4d which an outer peripheral surface on one end side brought into slide contact with the fitting reference hole 5 and an outer peripheral surface on the other end side made abut on the through hole 3d is formed between the male screw part 4a and head part 4b, and a flexible part 4e which has an outer diameter smaller than the cylindrical part 4d is formed between the cylindrical part 4d and head part 4b.SELECTED DRAWING: Figure 2

Description

  The present invention allows a cutting insert having an insert body formed with a cutting blade to be seated on a slit-like insert mounting seat formed at the tip of a tool body, and is detachable by being clamped by a clamp screw. The present invention relates to a cutting edge exchangeable cutting tool to be attached.

  As such a blade-tip-exchange-type cutting tool, for example, Patent Document 1 discloses a blade-tip-exchange-type cutting in which a cutting insert is sandwiched between hollow insert mounting seats provided in a slit shape at the tip of a tool body and fixed with a fastening member. In the tool, the insert mounting seat side surface portion of the tool body is provided with a cone receiving surface that is eccentric in the direction of the rear end of the tool body with respect to the center line of the fastening member at a portion corresponding to the head cone surface of the fastening member. On the side surface portion of the insert mounting seat, a cylindrical portion receiving hole of the tightening member and its side wall and a female thread portion corresponding to the male thread portion of the tightening member connected to the side wall are provided, and the cutting insert is fixed by pressing by the side surface portion of the insert mounting seat, It is performed by pressing from the pin hole side surface of the cutting insert to the rear end side of the tool body by the cylindrical portion of the clamping member, and tightening the side wall of the cylindrical portion receiving hole. Only those which are brought into contact with the cylindrical portion of the member and the mounting reference surface is proposed.

  Here, in the blade-tip-exchange-type cutting tool described in Patent Document 1, as described above, the portion corresponding to the tightening member head conical surface of the insert mounting seat side surface portion of the tool main body is located with respect to the center line of the tightening member. By providing a conical receiving surface that is eccentric in the direction of the rear end of the tool body, by screwing the tightening member, the head side is bent so that it tilts toward the rear end side of the tool body. It is pressing toward the rear end of the main body.

  Since the side wall of the cylindrical portion receiving hole and the cylindrical portion of the tightening member are brought into contact with each other as the mounting reference surface, the space between the lower end of the cylindrical portion and the front end side wall of the cylindrical portion receiving hole when the tightening member is bent in this way. The pressing force of the cutting insert by the cylindrical portion can be stabilized by pressing, and the mounting accuracy of the cutting insert can be kept high even with respect to loads in various directions and sizes during use of the tool.

Japanese Patent No. 3971522

  However, in the clamping member of the cutting edge exchangeable cutting tool described in Patent Document 1, the rigidity of the clamping member is high because the cylindrical portion is formed over the entire length between the male screw portion and the head. There is a problem that the fastening member is difficult to bend. In addition, since the cylindrical portion is formed over the entire length between the male screw portion and the head, the contact area between the cylindrical portion and the pin hole side surface of the cutting insert also increases, and the cylindrical portion becomes the pin hole side surface. The frictional resistance when pressing the tool toward the rear end side of the tool body also increases, and the cutting insert may be displaced when the fastening member is tightened.

  The present invention has been made under such a background. While stabilizing the pressing force of the cutting insert as described above, the clamping member (clamp screw) can be easily bent, and cutting can be performed at the time of tightening. An object of the present invention is to provide a cutting edge-exchangeable cutting tool capable of preventing a situation in which an insert is displaced.

  In order to solve the above-described problems and achieve such an object, the present invention provides a cutting insert having an insert body in which a cutting blade is formed on a slit-like insert mounting seat formed at a tip portion of a tool body. Is a cutting edge exchangeable cutting tool that is detachably attached by being clamped by a clamp screw, and the insert body includes a seating surface that can contact the bottom surface of the insert seat. A through hole through which the clamp screw is inserted is formed, and one of the two mounting seat walls facing each other of the insert mounting seat has a mounting reference hole and a screw. A conical receiving surface having a center line eccentric to the rear end side of the tool body with respect to the center line of the screw hole is formed on the other mounting seat wall surface. A head having a conical outer peripheral surface that can be slidably contacted with the conical receiving surface at one end of the clamp screw and formed at one end of the clamp screw. A portion is formed, and between the male screw portion and the head, the outer peripheral surface of the one end portion side of the clamp screw is brought into sliding contact with the inner peripheral surface of the mounting reference hole on the tip side of the tool body, A cylindrical portion is formed such that the outer peripheral surface on the other end side is brought into contact with the inner peripheral surface on the rear end side of the tool body in the through hole of the insert main body, and further, between the cylindrical portion and the head, A flexible portion having an outer diameter smaller than that of the cylindrical portion is formed.

  In the blade-type replaceable cutting tool configured in this way, when the clamp screw is screwed in and the cutting insert is attached, the outer peripheral surface of the cylindrical portion on the one end side where the male screw portion of the clamp screw is formed is the mounting reference hole. Since the inner peripheral surface of the tool main body tip side is slidably contacted, these inner and outer peripheral surfaces act as attachment reference surfaces in the cutting edge exchangeable cutting tool described in Patent Document 1. For this reason, similarly to the cutting edge exchangeable cutting tool described in Patent Document 1, the pressing force of the cutting insert is stabilized, and the cutting insert can be attached to loads in various directions and sizes during cutting. High machining accuracy can be obtained while maintaining high accuracy.

  Further, in the cutting edge replacement type cutting tool having the above configuration, a flexible portion having an outer diameter smaller than that of the cylindrical portion is formed between the cylindrical portion and the head of the clamp screw. Since the rigidity of the clamp screw can be reduced within a necessary range by forming the clamp screw, the clamp screw can be easily bent when the cutting insert is sandwiched and fixed. Therefore, the cutting insert can be securely and stably attached to the insert mounting seat even with a small screwing force.

  Moreover, since this flexible part has an outer diameter smaller than a circular head, it does not contact with the through-hole of an insert main body, ie, the contact area of a clamp screw and a through-hole can be reduced. As a result, the frictional resistance when the clamp screw presses the through hole toward the rear end side of the tool body is also reduced, so that it is possible to prevent a situation in which the insert body moves when the clamp screw is tightened. For this reason, the mounting accuracy of the cutting insert can be further increased, and the processing accuracy can be further improved.

  Here, when the outer diameter of the cylindrical portion is originally small and easily bent, the length of the flexible portion in the portion between the male screw portion and the head needs to be increased so much. There is no. However, on the contrary, when the outer diameter of the cylindrical portion is large and difficult to bend, the clamp screw is easily bent as described above, and the contact area between the inner peripheral surface of the through hole of the insert body and the outer peripheral surface of the cylindrical portion is reduced. In order to suppress, the boundary between the cylindrical portion and the flexible portion is the insert in the center line direction of the screw hole from the one mounting seat wall surface in a state where the clamp screw is screwed and the cutting insert is sandwiched. It is desirable to be located within a range of 1/2 or less of the thickness of the main body.

  As described above, according to the present invention, it is possible to attach the cutting insert to the insert mounting seat reliably and with high accuracy while stabilizing the pressing force of the cutting insert by the clamp screw. Can be achieved.

It is a side view of the front-end | tip part of the blade-tip-exchange-type cutting tool which shows the 1st Embodiment of this invention. It is ZZ sectional drawing in FIG. It is a figure equivalent to the ZZ sectional view in Drawing 1 showing the 2nd embodiment of the present invention.

  1 and 2 show a first embodiment of the present invention. The blade-tip-exchangeable cutting tool of the present embodiment is a blade-tip-exchangeable end mill, particularly a ball end mill, that is, the distal end portion of the tool body 1 having a substantially cylindrical shape centering on the axis O (the left portion in FIGS. 1 and 2). The cutting insert 3 having the insert main body 3b in which the arc-shaped cutting blade 3a is formed is seated on the slit-shaped insert mounting seat 2 formed in FIG. It is attached. Such a blade-tip-exchangeable cutting tool is usually fed out in a direction intersecting with the axis O while a shank portion (not shown) on the rear end side of the tool body 1 is gripped by the spindle of the machine tool and rotated around the axis O. The workpiece such as a die is cut by the cutting blade 3a.

  The insert body 3b of the cutting insert 3 is formed in a plate shape from a hard material such as cemented carbide, and includes two mutually parallel side surfaces 3c and a seating surface 3d perpendicular to the side surfaces 3c. The arcuate cutting edge 3a protrudes from the outer periphery of the tip end of the tool body 1 and is attached to the insert mounting seat 2 so that the rotation trajectory formed around the axis O becomes a hemisphere centered on the axis O. The insert body 3b has a circular through-hole 3e having a center line passing through the approximate center of the arc formed by the cutting edge 3a and penetrating the insert body 3b. The two side surfaces 3c are formed on the two side surfaces 3c. It is open.

  On the other hand, the tool body 1 and the clamp screw 4 are formed of a metal material such as a steel material that is lower in hardness than the insert body 3b and can be elastically deformed. Among these, the tip of the tool body 1 is formed in a hemispherical shape centering on the intersection of the axis O and the center line of the through hole 3e of the insert body 3b with the cutting insert 3 attached thereto. However, the radius of the hemisphere formed by the tip of the tool body 1 is slightly smaller than the radius of the hemisphere formed by the rotation locus of the cutting edge 3a.

  As shown in FIG. 2, the insert mounting seat 2 formed at the tip of the tool body 1 is a tool viewed from a direction perpendicular to the axis O and the center line of the through hole 3e of the insert body 3b. Two mounting seat wall surfaces 2a, 2b facing each other parallel to each other and parallel to the axis O, and these mounting seat wall surfaces 2a, And a mounting seat bottom surface 2c that is perpendicular to the axis 2b and perpendicular to the axis O and faces the tip side of the tool body 1.

  The two mounting seat wall surfaces 2a and 2b are at an equal distance from the axis O, and the interval between the mounting seat wall surfaces 2a and 2b is such that the two side surfaces 3c are in sliding contact with the mounting seat wall surfaces 2a and 2b, respectively. The insert body 3b is sized to fit. Then, by inserting the insert main body 3b and bringing the seating surface 3d into contact with the mounting seat bottom surface 2c in this way, the cutting insert 3 is inserted into the insert mounting seat 2 so that the center line of the through hole 3e is orthogonal to the axis O. To be seated.

  In addition, the cutting insert 3 is seated on the insert mounting seat 2 as described above on one mounting seat wall surface (the lower mounting seat wall surface in FIG. 2) of the two mounting seat wall surfaces 2a and 2b. The mounting reference hole 5 and the screw hole 6 are formed so as to face the opening of the through hole 3e in the side surface 3c of the insert body 3b that is in sliding contact with the one mounting seat wall surface 2a. In the present embodiment, the attachment reference hole 5 is formed so as to open to the attachment seat wall surface 2 a, and the screw hole 6 is formed at the bottom of the attachment reference hole 5.

  Among these, the screw hole 6 extends so that the center line L1 thereof is orthogonal to the axis O. Further, the attachment reference hole 5 has a long hole shape extending in the direction of the axis O, that is, in a cross section parallel to the attachment seat wall surface 2a, two semicircles obtained by dividing one circle by its diameter in the direction of the axis O. It is formed in a shape in which the space is connected by a square having a width equal to this diameter. Of these semicircles, the center of the semicircle located on the tip side of the tool body 1 is located on the center line L1 of the screw hole 6, and the semicylindrical surface of the mounting reference hole 5 along this semicircle on the tip side. The inner peripheral surface is a mounting reference surface 5a on the tool body 1 side. Note that the inner diameters of these semicircles (the diameter of the one circle) are slightly larger than the inner diameters of the screw holes 6 (the diameters of the screw valleys of the screw holes 6).

  On the other hand, of the two mounting seat wall surfaces 2a and 2b, the other mounting seat wall surface (upper mounting seat wall surface in FIG. 2) 2b is separated from the other mounting seat wall surface 2b and the tip portion of the tool body 1 is provided. A concave conical hole 7 whose inner diameter gradually increases toward the outer peripheral side (upper side in FIG. 2) is formed and opened on the outer peripheral surface of the tool body 1. In the cross section parallel to the mounting seat wall surface 2 b, the concave conical hole 7 is formed in a circular shape, and the inner diameter of the circle gradually increases as it goes toward the outer peripheral side of the tool body 1.

  Furthermore, the semiconical surface along the semicircle on the tip side of the tool body 1 of the concave conical hole 7 is a conical receiving surface 7a in the present embodiment, and the center line L2 of the conical receiving surface 7a is It is orthogonal to the axis O and is slightly eccentric to the rear end side of the tool body 1 with respect to the center line L1 of the screw hole 6. An elongated hole portion 7b having an inner diameter larger than the attachment reference hole 5 is formed between the hole bottom of the concave conical hole 7 and the other attachment seat wall surface 2b, and the other attachment seat wall surface 2b. It opens so that it may face the opening part of the through-hole 3e in the side surface 3c of the insert main body 3b which slidably contacted.

  The clamp screw 4 is formed with a male screw portion 4a that is screwed into the screw hole 6 at one end (the lower portion in FIG. 2), and is thus male at the other end (the upper portion in FIG. 2). When the screw portion 4a is screwed into the screw hole 6, a head portion 4b having a conical outer peripheral surface that gradually increases in diameter toward the one end side capable of sliding contact with the conical receiving surface 7a is formed. Yes. Further, an engagement hole 4c that engages with a work tool such as a wrench when the clamp screw 4 is screwed or loosened is formed on the end face of the head 4b.

  Further, a cylindrical portion 4d is formed between the male screw portion 4a and the head portion 4b on one end side where the male screw portion 4a is provided. The cylindrical portion 4d has a cylindrical surface whose outer peripheral surface is centered on the center line of the clamp screw 4, and its outer diameter is slightly larger than the outer diameter of the male screw portion 4a. Is set to be slightly smaller than the inner diameter of the inner peripheral surface on the distal end side which is the mounting reference surface 5a, and when the male screw portion 4a is screwed into the screw hole 6 as described above, the outer periphery of the cylindrical portion 4d The surface can be brought into sliding contact with the attachment reference surface 5a.

  Note that the through hole 3e of the insert body 3b is formed when the male thread portion 4a starts to be screwed into the screw hole 6 with the insert body 3b seated on the insert mounting seat 2 as described above. The position of the center line and the inner diameter are set so that a very slight space is provided between the surface and the inner peripheral surface of the rear end side portion of the tool body 1 of the through hole 3e.

  A flexible portion 4e having an outer diameter smaller than that of the cylindrical portion 4d is formed between the cylindrical portion 4d and the head portion 4b. The flexible portion 4e also has a cylindrical surface whose outer peripheral surface is centered on the center line of the clamp screw 4. The difference in outer diameter (diameter) between the cylindrical portion 4d and the flexible portion 4e is, for example, 0. 0.08 to 0.5 mm. In the present embodiment, the length of the flexible portion 4e in the center line direction of the clamp screw 4 is shorter than the length of the cylindrical portion 4d.

  Such a blade-tip-exchangeable cutting tool fits the cutting insert 3 as described above into the insert mounting seat 2 so that the center line of the through hole 3e of the insert main body 3b is orthogonal to the axis O, and the seating surface 3d is formed. Assembling is carried out by contacting the mounting seat bottom surface 2c and then inserting the clamp screw 4 from the concave conical hole 7 into the through hole 3e and screwing the male screw portion 4a into the screw hole 6.

  When the male screw portion 4a starts to be screwed into the screw hole 6, the center line of the clamp screw 4 is coaxial with the center line L1 of the screw hole 6, but the outer peripheral surface of the head 4b of the clamp screw 4 is the concave conical hole 7 Since the center line L2 of the conical receiving surface 7a is slightly offset from the center line L1 of the screw hole 6 toward the rear end side of the tool body 1, the clamp screw 4 is The head 4b begins to bend so that it falls into the rear end side of the tool body 1.

  When the clamp screw 4 is bent in this way, the outer peripheral surface on the other end side of the cylindrical portion 4d comes into contact with the inner peripheral surface on the rear end side of the tool main body 1 of the through hole 3e of the cutting insert 3 and the insert main body. 3 b is pressed against the mounting seat bottom surface 2 c of the insert mounting seat 2. At the same time, the head 4b of the clamp screw 4 presses the conical receiving surface 7a, so that the interval between the two mounting seat wall surfaces 2a, 2b of the insert mounting seat 2 is narrowed, and the two side surfaces of the insert body 3b. 3c is pressed and the cutting insert 3 is clamped by the insert mounting seat 2 by these presses, and is fixed.

  Here, when the clamp screw 4 starts to bend, since the outer peripheral surface on one end side of the cylindrical portion 4d is in sliding contact with the mounting reference surface 5a on the tip end side of the tool body 1 of the mounting reference hole 5, the clamp screw 4 is The head 4b side bends so that the head 4b side is inclined toward the rear end side of the tool body 1 with a portion slidably in contact with the mounting reference surface 5a on the outer peripheral surface on one end side of the cylindrical portion 4d. That is, the portion of the cylindrical portion 4d that is in sliding contact with the attachment reference surface 5a acts as an attachment reference surface on the clamp screw 4 side, and the clamp screw 4 is connected to the distal end side of the tool body 1 by the attachment reference surface 5a on the tool body 1 side. Since it is constrained to the outer peripheral side, the cutting insert 3 can be firmly held on the insert mounting seat 2 even if a load acts on the cutting insert 3 from the cutting edge 3a during cutting.

  Further, in the blade-tip-exchangeable cutting tool having the above configuration, a flexible portion 4e having an outer diameter smaller than that of the cylindrical portion 4d is formed between the cylindrical portion 4d and the head portion 4b on the other end side of the clamp screw 4. ing. For this reason, in the flexible part 4e, since rigidity can be made smaller in the necessary range than the cylindrical part 4d, the clamp screw 4 can be easily bent, and a work tool such as a wrench can be placed in the engagement hole 4c. By engaging and rotating the clamp screw 4, the screwing force when the male screw portion 4 a is screwed into the screw hole 6 can be suppressed to a small level, and the cutting insert 3 can be stably bent by securely bending the clamp screw 4. It can be fixed to the insert mounting seat 2.

  Further, since the flexible portion 4e has a smaller outer diameter than the cylindrical portion 4d that abuts the through hole 3e of the insert body 3b, the flexible portion 4e does not contact the through hole 3e, and therefore the contact between the clamp screw 4 and the through hole 3e. The area becomes smaller. For this reason, the frictional resistance between the clamp screw 4 and the through hole 3e when the clamp screw 4 abuts the through hole 3e and presses the insert body 3b toward the rear end side of the tool body 1 can be suppressed. The insert body 3b can be prevented from shifting when the clamp screw 4 is tightened immediately before the cutting insert 3 is completely fixed, and the cutting insert 3 is attached to the insert mounting seat 2 with higher accuracy. The accuracy can be improved.

  In addition, since the flexible portion 4e that does not contact the through hole 3e is formed between the cylindrical portion 4d on the other end side of the clamp screw 4 and the head portion 4b in this way, the male screw portion 4a and the head portion 4b As compared with the case where the entire portion between them is the cylindrical portion 4d in contact with the through-hole 3e, the position where the outer peripheral surface of the cylindrical portion 4d contacts with the through-hole 3e due to the bending of the clamp screw 4 It can be brought close to the outer peripheral surface on the one end portion side of the cylindrical portion 4d to be a surface. Therefore, even if the amount of bending of the clamp screw 4 is the same, the pressing force acting on the position where the cylindrical portion 4d contacts the through hole 3e can be increased with the outer peripheral surface on the one end side as a fulcrum, and the cutting insert 3 can be further strengthened. Can be fixed to the insert mounting seat 2.

  In the first embodiment, the length of the flexible portion 4e in the center line direction of the clamp screw 4 is shorter than the length of the cylindrical portion 4d, and the outer periphery of the cylindrical portion 4d is shown in FIG. The surface comes into contact with the through hole 3e around the center of the thickness of the insert body 3b in the direction of the center line of the through hole 3e. For this reason, the cutting insert 3 can be pressed with a good balance in the thickness direction of the insert body 3b, and can be more stably fixed to the insert mounting seat 2. In addition, by making the length of the flexible portion 4e shorter than the cylindrical portion 4d in this way, it is possible to prevent the rigidity and strength of the clamp screw 4 from being lowered more than necessary, and to prevent breakage and the like.

  However, in the case where the outer diameter of the clamp screw 4 is originally large and the outer diameter of the cylindrical portion 4d and the flexible portion 4e can be increased, and sufficient rigidity and strength can be secured, FIG. As in the second embodiment of the present invention showing a cross section, the length of the flexible portion 4e is made longer than that of the cylindrical portion 4d, and the boundary between the cylindrical portion 4d and the flexible portion 4e is clamped by a clamp screw. In a state where the cutting insert 3 is sandwiched by screwing 4, the cutting insert 3 is positioned within a range A that is not more than ½ of the thickness of the insert body 3 b in the center line direction L 1 of the screw hole 6 from the one mounting seat wall surface 2 a. It may be. In FIG. 3, the same reference numerals are assigned to portions common to the first embodiment shown in FIGS. 1 and 2, and description thereof is omitted.

  Therefore, according to such a 2nd embodiment, even when clamp screw 4 is hard to bend, it can be made easy to bend reliably by ensuring flexible part 4e long. Further, since the contact area with the through hole 3e is smaller than in the first embodiment, the frictional resistance can be further reduced, and the outer peripheral surface of the cylindrical portion 4d is in contact with the through hole 3e. The position can be brought closer to one end side of the cylindrical portion 4d that is the attachment reference surface of the clamp screw 4, and the cutting insert 3 can be fixed more firmly.

  However, if the position of this boundary is too close to one mounting seat wall surface 2a, the absolute contact area between the cylindrical portion 4d and the through hole 3e is insufficient, and the balance of the pressing position in the thickness direction of the insert body 3b is insufficient. Since the attachment of the cutting insert 3 may become unstable, the boundary between the cylindrical portion 4d and the flexible portion 4e is thus positioned within the above range A from the one mounting seat wall surface 2a. However, it is desirable to dispose at least 20% or more of the thickness of the insert body 3b from the mounting seat wall surface 2a.

  In addition, in these 1st, 2nd embodiment, although the case where this invention was applied to the blade end exchange-type ball end mill in which the rotation locus | trajectory of the cutting blade 3a of the cutting insert 3 makes a hemisphere was demonstrated, the same blade edge exchange type Even in the end mill, for example, the cutting edge is a bottom blade extending in a direction substantially perpendicular to the axis O, and the outer peripheral blade whose rotation trajectory around the axis O is connected to the outer peripheral end of the bottom blade and forms a cylindrical surface centered on the axis O. It is also possible to apply the present invention to a square end mill constructed from the above, or a radius end mill in which an arcuate corner blade is formed in a corner portion where the bottom blade and the outer peripheral blade intersect. Further, the present invention may be applied to a cutting tool other than the end mill, for example, a blade-tip exchange type drill.

DESCRIPTION OF SYMBOLS 1 Tool main body 2 Insert mounting seat 2a, 2b Mounting seat wall surface 2c Mounting seat bottom surface 3 Cutting insert 3a Cutting blade 3b Insert main body 3c Side surface 3d Seating surface 3e Through-hole 4 Clamp screw 4a Male thread part 4b Head part 4c Engagement hole 4d Cylindrical Part 4e Flexible part 5 Reference mounting hole 5a Reference mounting surface 6 Screw hole 7 Conical concave hole 7a Conical receiving surface 7b Long hole O Tool body 1 axis L1 Center line of screw hole 6 L2 Conical receiving surface 7a Centerline A A range of one half or less of the thickness of the insert body 3b in the centerline direction L1 of the screw hole 6 from the one mounting seat wall surface 2a.

Claims (2)

Cutting edge replacement that allows a cutting insert having an insert body formed with a cutting edge to be seated on a slit-like insert mounting seat formed at the tip of the tool body and detachably attached by clamping with a clamp screw Type cutting tool,
The insert body is formed with a seating surface capable of contacting the mounting seat bottom surface of the insert mounting seat, and a through hole through which the clamp screw is inserted through the insert body.
Of the two mounting seat wall surfaces of the insert mounting seat facing each other, one mounting seat wall surface is formed with a mounting reference hole and a screw hole, and the other mounting seat wall surface has a center line of the screw hole. On the other hand, a conical receiving surface having a center line eccentric to the rear end side of the tool body is formed on the front end side of the tool body.
A male screw portion to be screwed into the screw hole is formed at one end portion of the clamp screw, and a head portion having a conical outer peripheral surface capable of sliding contact with the conical receiving surface is formed at the other end portion.
Between the male screw portion and the head, the outer peripheral surface on the one end portion side of the clamp screw is brought into contact with the inner peripheral surface on the tip end side of the tool main body of the mounting reference hole, and the other end portion side. A cylindrical portion is formed so that the outer peripheral surface of the inner surface of the through hole of the insert main body is in contact with the inner peripheral surface on the rear end side of the tool body, and between the cylindrical portion and the head portion, A cutting edge exchangeable cutting tool characterized in that a flexible part having a small outer diameter is formed.   The thickness of the insert body in the direction of the center line of the screw hole from the one mounting seat wall surface in a state where the boundary between the cylindrical portion and the flexible portion is screwed in the clamp screw and sandwiches the cutting insert. The cutting edge exchangeable cutting tool according to claim 1, wherein the cutting tool is located in a range of 1/2 or less of the above.

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