KR102025532B1 - Replaceable tool edge cutting tool - Google Patents

Abstract

In this blade exchangeable cutting tool, the cutting insert is seated on the insert mounting sheet and is detachably mounted by being clamped by the clamp screw. A male thread portion is formed at one end of the clamp screw, and a head portion having an outer circumferential surface on the other end is formed at the other end. The first cylindrical portion is formed between the male screw portion and the head portion, the second cylindrical portion is formed on the head portion side, and the first flexible portion is formed between the first and second cylindrical portions.

Description

Interchangeable Blade Cutting Tool {REPLACEABLE TOOL EDGE CUTTING TOOL}

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cutting edge exchangeable cutting tool in which a cutting insert having an insert body with a cutting edge is seated on a slit insert mounting sheet formed at the tip end of the tool main body and is detachably mounted by being clamped by a clamp screw.

This application claims priority based on Japanese Patent Application No. 2015-186854 for which it applied to Japan on September 24, 2015, and uses the content here.

In such a blade tip cutting type cutting tool, for example, Patent Document 1, in a blade tip type cutting tool for clamping the cutting insert in the insert-mounting sheet of the hollow portion formed in the slit-shaped portion of the tool main body and fixed with a fastening member, On the insert mounting seat side surface of the tool body, a conical receiving surface eccentrically formed in the rear end direction of the tool body with respect to the center line of the fastening member is formed at a portion corresponding to the head portion conical surface of the fastening member, and on the other insert mounting seat side surface, A cylindrical portion receiving hole and a side wall connected to the side wall to form a female thread portion corresponding to the male thread portion of the fastening member, the fixing of the cutting insert being pressed by the insert mounting seat side portion, and the cutting insert by the cylindrical portion of the fastening member. By pressing from the pin hole side surface to the rear end side of the tool body, It is proposed that the side wall of the receiving hole and the cylindrical portion of the fastening member abut to be a mounting reference plane.

Here, in the blade tip exchange type cutting tool described in this Patent Document 1, as described above, the part corresponding to the fastening member head portion conical surface of the insert mounting seat side portion of the tool main body is eccentric in the tool main body rear end direction with respect to the center line of the fastening member. By forming the conical receiving surface, the fastening member is bent so that the head part side of the fastening member is inclined toward the rear end side of the tool body by twisting the fastening member, and the pin hole side of the cutting insert is reared by the cylindrical part of the fastening member. It is pressurized to the side.

Since the side wall of the cylindrical portion receiving hole and the cylindrical portion of the fastening member are brought into contact with each other to form a mounting reference plane, the cylinder is pressed by the pressure between the lower end of the cylindrical portion and the side wall of the cylindrical portion receiving hole when the fastening member is bent. The pressing force of the cutting insert by the negative part can be stabilized, and the mounting precision of the cutting insert can be maintained with high accuracy even in the loads of various directions and sizes during use of the tool.

Japanese Patent Publication No. 3971522

By the way, in the fastening member of the blade tip exchange type cutting tool described in this patent document 1, since this cylindrical part is formed over the full length between a male screw part and a head part, the rigidity of a fastening member is high and the problem that a fastening member does not bend well is a problem. there was. Moreover, since the cylindrical portion is formed over the entire length between the male screw portion and the head portion, the contact area between the cylindrical portion and the pin hole side of the cutting insert is also increased, and the friction when the cylindrical portion presses the pin hole side to the tool body rear end side. The resistance is also large, and there is a fear that the cutting insert may move unevenly when the fastening member is fastened.

The present invention has been made under such a background, and as described above, the clamping member (clamp screw) can be easily bent while stabilizing the pressing force of the cutting insert, and the cutting insert is shifted at the time of tightening. It is an object of the present invention to provide a cutting edge exchangeable cutting tool that can be prevented.

In order to solve the said subject and achieve such an objective, in this invention, the cutting insert which has the insert main body with a cutting edge is seated in the slit-shaped insert mounting sheet formed in the front-end | tip part of a tool main body, and clamps by clamp screw. The blade insert exchangeable cutting tool detachably mounted thereon, wherein the insert main body is provided with a seating surface which can contact the bottom surface of the insert seat of the insert mounting sheet, and a through hole through which the clamp screw is inserted through the insert main body. The mounting reference hole and the screw hole are formed in one of the mounting seat wall surfaces of the two mounting seat walls facing each other of the insert mounting sheet, and the other mounting seat wall surface is eccentric to the rear end of the tool body with respect to the center line of the screw hole. A conical receiving surface having a center line is formed on the tool body tip side, One end portion of the clamp screw is provided with a male screw portion to be screwed into the screw hole, and the other end portion has a head portion having an outer circumferential surface on the conical surface which is slidable in contact with the conical receiving surface, and between the male screw portion and the head portion, On the male screw portion, a first cylindrical portion whose outer circumferential surface abuts on the inner circumferential surface of the tool main body tip side of the mounting reference hole is formed, while the outer circumferential surface of the head portion side has an inner circumferential surface of the tool main body rear end side in the through hole of the insert main body. The 2nd cylindrical part which contact | connects to is formed, Furthermore, the 1st flexible part whose outer diameter is smaller than the 1st, 2nd cylindrical part is formed between these 1st and 2nd cylindrical parts, It is characterized by the above-mentioned.

In the blade exchangeable cutting tool configured as described above, when the clamp screw is twisted to mount the cutting insert, the outer circumferential surface of the first cylindrical portion on the male screw portion side of the clamp screw is in sliding contact with the inner circumferential surface of the tool body tip side of the mounting reference hole. Therefore, these inner and outer circumferential surfaces act as mounting reference surfaces in the blade tip exchange type cutting tool described in Patent Document 1. For this reason, similar to the blade-end cutting tool described in Patent Literature 1, the pressing force of the cutting insert is stabilized, and the mounting precision of the cutting insert is maintained with high accuracy even for loads of various directions and sizes during cutting. Can be obtained. In addition, the outer circumferential surface of the second cylindrical portion on the head side of the clamp screw presses the through hole of the cutting insert toward the rear end of the tool body due to the bending of the clamp screw, and presses the seating surface of the insert body against the mounting seat bottom surface of the insert mounting sheet. .

In addition, in the blade tip exchange type cutting tool of the above configuration, a first flexible portion having an outer diameter smaller than those of the first and second cylindrical portions is formed between the first and second cylindrical portions. Since the rigidity of a clamp screw can be made small in a required range by forming, it can make it easy to bend a clamp screw when clamping and fixing a cutting insert. Therefore, the cutting insert can be mounted reliably and stably on the insert mounting sheet even with a small twisting force.

In addition, since the outer diameter of the first flexible portion is smaller than that of the first and second one-head portions, the first flexible portion does not come into contact with the through hole of the insert body, that is, the contact area between the clamp screw and the through hole can be reduced. With this, the frictional resistance when the clamp screw presses the through hole toward the rear end of the tool main body is also reduced, so that the insert main body can be prevented from shifting when the clamp screw is tightened. For this reason, the mounting precision of a cutting insert can be made more accurate, and further improvement of processing precision can be attained.

Moreover, it is preferable to form the 2nd flexible part whose outer diameter is smaller than a said 2nd cylindrical part also between a said 2nd cylindrical part and a said head part. As a result, the clamp screw can be more easily bent, and the contact area with the through hole can be further reduced.

Moreover, on the extended surface of the said one side of the mounting sheet wall of the said insert mounting sheet, or this extension, in the state which clamped the said cutting insert by clamping the said clamp screw to the boundary of a said 1st cylindrical part and a said 1st flexible part. It is preferable to locate in the said mounting reference hole from a surface. This eliminates the case where the first cylindrical portion is in contact with the through-hole of the insert body, and therefore, when the clamp screw is tightened when the clearance between the first cylindrical portion and the through-hole of the insert body is small, for example, The occurrence of a deviation in the mounting shake precision of the insert main body can be prevented by the contact between the part and the through hole of the insert main body.

As described above, according to the present invention, the cutting insert can be mounted on the insert mounting sheet reliably and with high accuracy while stabilizing the pressing force of the cutting insert by the clamp screw, and the cutting operation can be further precisely achieved. .

BRIEF DESCRIPTION OF THE DRAWINGS It is a side view of the front-end | tip of the blade exchangeable cutting tool which shows one Embodiment of this invention.
FIG. 2 is a sectional view taken along line ZZ in FIG. 1.

1 and 2 show one embodiment of the present invention. The cutting edge exchange type cutting tool of the present embodiment is a cutting edge exchange type end mill, in particular, a ball end mill, that is, a tip portion of an outline approximately circumferential tool main body 1 centered on the axis O (in FIGS. 1 and 2). The cutting insert 3 which has the insert main body 3b in which the arc-shaped cutting edge 3a was formed in the slit-shaped insert mounting sheet 2 formed in the left part in this part is seated, and is clamped by the clamp screw 4 The cutting insert 3 is detachably attached to the insert mounting sheet 2 by being (the cutting insert 3 is clamped to the insert mounting sheet 2 by tightening the clamp screw 4). In such a blade tip cutting type cutting tool, an unshown shank portion at the rear end side of the tool main body 1 is gripped by the main shaft of the machine tool, and is rotated around the axis O, and is usually sent out in a direction crossing the axis O. The workpieces such as molds are cut by the cutting edge 3a. In addition, in this embodiment, the direction toward the insert mounting sheet 2 from the shank part of the tool main body 1 in the direction which the axis line O extends is called a front end side (left side of FIG. 1, 2), The direction toward the shank portion from the insert mounting sheet 2 is referred to as the rear end side (right side in FIGS. 1 and 2). In addition, the direction orthogonal to the axis line O is called radial direction. The direction approaching the axis O in the radial direction is called radial inward, and the direction away from the axis O is called radial outward.

In addition, in this embodiment, the blade tip exchange type cutting tool provided with the clamp screw 4 whose screw size is the range of M2-M8 is mainly object, but after that, the blade tip provided with the clamp screw 4 whose screw size is M8. The interchangeable cutting tool is described. In addition, the screw size of the clamp screw 4 of the blade exchangeable cutting tool of this invention is not limited to the said range.

The insert body 3b of the cutting insert 3 is formed into a plate shape by a hard material such as cemented carbide, and has two mutually parallel side surfaces 3c and a seating surface 3d perpendicular to these side surfaces 3c. The cutting edge 3a of the said circular arc shape (approximately semi-circle shape) protrudes to the outer periphery (tip side and radial direction outward) of the tip part of the tool main body 1, and is the rotational trajectory formed around the axis O. It is attached to the insert mounting sheet 2 so that it may become hemispherical which has a center on this axis O. In other words, the insert main body 3b is attached to the insert mounting sheet 2 so that the center of the circular arc which the cutting edge 3a makes may pass along the axis O. As shown in FIG. Moreover, the insert main body 3b is provided with the cross-sectional circular through-hole 3e which penetrates the insert main body 3b with the center line which passes through the substantially center of the circular arc which the said cutting edge 3a makes. And the two side surfaces 3c.

On the other hand, the tool main body 1 and the clamp screw 4 are formed of metal materials, such as steel materials which are low hardness and can elastically deform than the insert main body 3b. Among these, the distal end portion of the tool main body 1 has a hemispherical shape centered on the intersection of the axis line O and the center line of the through hole 3e of the insert main body 3b in a state where the cutting insert 3 is mounted. It is formed. However, the radius of the hemisphere formed by the distal end of the tool main body 1 is slightly smaller than the radius of the hemisphere formed by the rotational trajectory of the cutting edge 3a.

As shown in FIG. 2, the insert mounting sheet 2 formed at the distal end portion of the tool main body 1 has a direction perpendicular to the center line of the through hole 3e of the axis O and the insert main body 3b. In view of the above, two mounting sheet wall surfaces 2a and 2b opposed to each other, which are formed in a slit shape that are U-shaped open at the tip side of the tool body 1, that are parallel to each other and also parallel to the axis O, and these The mounting sheet bottom surface 2c which faces the tip side of the tool main body 1 perpendicular to the mounting sheet wall surfaces 2a and 2b and orthogonal to the axis O is provided.

The two mounting sheet wall surfaces 2a and 2b are at the same distance from each other from the axis O, and the gap between these mounting sheet wall surfaces 2a and 2b is such that the insert body 3b is formed on both mounting sheet wall surfaces 2a and 2b. The two side surfaces 3c of) are each in sliding contact so that the insert main body 3b can be inserted. In this way, by inserting the insert main body 3b and making the said seating surface 3d abut on the mounting seat bottom surface 2c, the cutting insert 3 has the centerline of the through-hole 3e orthogonal to the axis O. The seat is seated on the insert mounting sheet 2.

Moreover, the cutting insert 3 is provided in the 1st mounting sheet wall surface (lower mounting sheet wall surface in FIG. 2) which is one mounting sheet wall surface among two mounting sheet wall surfaces 2a, 2b as mentioned above. ) To face the opening of the through hole 3e in the side surface 3c of the insert body 3b in sliding contact with the first mounting sheet wall surface 2a in a state where it is seated on the insert mounting sheet 2. The mounting reference hole 5 and the screw hole 6 are formed. In the present embodiment, the mounting reference hole 5 is formed to be open to the mounting sheet wall surface 2a, and the screw hole 6 is formed in the bottom of the hole (outward in the radial direction) of the mounting reference hole 5. .

Among these, the screw hole 6 is extended so that the center line L1 may orthogonally cross the axis line O. As shown in FIG. Moreover, the mounting reference hole 5 has comprised the long hole shape (track shape) extended in the axis line O direction, ie, in the cross section parallel to the mounting sheet wall surface 2a, one circle is axial-axis in the diameter. It is formed in the shape which connected between two semicircle divided in the (O) direction by the square (square) of the same width as this diameter. The center of the semicircle located in the front end side of the tool main body 1 of these semicircles is located on the center line L1 of the screw hole 6, and on the semicylindrical surface of the mounting reference hole 5 along the semicircle of this front end side. The inner circumferential surface of the surface becomes the mounting reference surface 5a on the tool main body 1 side. In addition, the inner diameter of these semicircles (diameter of the said one circle) is slightly larger than the inner diameter of the screw hole 6 (diameter of the valley of the screw of the screw hole 6).

On the other hand, in the 2nd mounting sheet wall surface (upper mounting sheet wall surface in FIG. 2) which is the other mounting sheet wall surface among the two mounting sheet wall surfaces 2a, 2b, this 2nd mounting sheet wall surface 2b A concave conical hole 7 whose inner diameter gradually increases toward the tip outer peripheral side (upper side in Fig. 2, radially outward in Fig. 2) away from the tool main body 1 is formed, and the outer peripheral surface of the tool main body 1 It is open to. In the cross section of the tool main body 1 parallel to the mounting sheet wall surface 2b, this concave conical hole 7 is formed in circular shape, and the inner diameter of this circle is the outer peripheral side (diameter of the tool main body 1). Direction gradually outward).

Moreover, the semiconical surface along the semicircle along the front end side of the tool main body 1 of this concave conical hole 7 is set as the conical receiving surface 7a in this embodiment, and this conical receiving surface 7a is carried out. The center line L2 of) is orthogonal to the axis line O, and is eccentrically to the rear end side of the tool main body 1 rather than the center line L1 of the screw hole 6. Moreover, center line L2 is parallel to center line L1. In addition, between the bottom of the hole of the concave conical hole 7 (the radially inner end of the concave conical hole 7) and the second mounting sheet wall surface 2b, it is larger than the mounting reference hole 5. The long hole 7b of the inner diameter is formed continuously with the concave conical hole 7. The long hole 7b has a width equal to this diameter between two semicircles in which one circle (a circle having a diameter larger than the diameter of the semicircle of the mounting reference hole 5) is divided from the diameter in the axis O direction. It is formed in the shape connected in the rectangle of. And the midpoint of the center of the two semicircles of the long hole 7b is located on the centerline L1 of the screw hole 6. The second mounting sheet wall surface 2b faces the opening of the through hole 3e in the side surface 3c of the insert body 3b in sliding contact with the second mounting sheet wall surface 2b. ) Is opened.

The clamp screw 4 is provided with a male screw portion 4a which is screwed into the screw hole 6 at one end portion (lower portion in FIG. 2), and the other end portion (upper portion in FIG. 2). ), A head portion having a conical outer circumferential surface which is gradually enlarged toward the other end side in sliding contact with the conical receiving surface 7a when the male screw portion 4a is screwed into the screw hole 6. 4b) is formed. Moreover, in the end surface of the head part 4b, the engaging hole 4c which engages with a working tool, such as a wrench, is provided in the clamp screw 4 when twisting or loosening.

Moreover, between these male screw portions 4a and the head portion 4b, a first cylindrical portion 4d is formed on one end side where the male screw portion 4a is formed. This first cylindrical portion 4d has a cylindrical surface with its outer circumferential surface centered on the centerline of the clamp screw 4, and its outer diameter is slightly larger than the outer diameter of the male screw portion 4a, and the mounting reference hole 5 Is set slightly smaller than the inner diameter of the inner circumferential surface of the distal end side, which has become the mounting reference surface 5a. As mentioned above, when the external thread part 4a is twisted into the screw hole 6, the outer peripheral surface of the 1st cylindrical part 4d becomes sliding contact with the attachment reference surface 5a. In this embodiment, the connection part containing an incomplete screw part is formed between the 1st cylindrical part 4d and the external thread part 4a. It is preferable that a connection part is smaller than the bone diameter of the male screw part 4a, and it has an outer diameter smaller than the outer diameter of the 1st, 2nd flexible parts 4f and 4g mentioned later.

On the other hand, the center line of the clamp screw 4 is located on the other end side between the male screw portion 4a and the head portion 4b (between the first cylindrical portion 4d and the head portion 4b) where the head portion 4b is formed. In the direction, the second cylindrical portion 4e is formed at intervals from the first cylindrical portion 4d. The outer peripheral surface of this 2nd cylindrical part 4e also forms the cylindrical surface centering on the centerline of the clamp screw 4, The outer diameter is set similarly to the 1st cylindrical part 4d. The length of the second cylindrical portion 4e in the centerline direction of the clamp screw 4 is set longer than the first cylindrical portion 4d in this embodiment. In addition, the preferable range of the length of the 1st cylindrical part 4d in the centerline direction of the clamp screw 4 changes with the screw size of the clamp screw 4. For example, when the screw size of the clamp screw 4 is M8 like this embodiment, it is preferable that the said length of the 1st cylindrical part 4d is 10 to 50% of the length of the 2nd cylindrical part 4e, Although it is preferable that it is 20 to 40%, it is not limited to this.

And between these 1st, 2nd cylindrical parts 4d and 4e, the 1st flexible part 4f whose outer diameter is smaller than the 1st and 2nd cylindrical parts 4d and 4e is formed. In addition, in this embodiment, between the 2nd cylindrical part 4e and the head part 4b of the clamp screw 4, the 2nd flexible part 4g whose outer diameter is smaller than the 2nd cylindrical part 4e is formed, have. Also in these 1st, 2nd flexible parts 4f and 4g, the outer peripheral surface forms the cylindrical surface centering on the centerline of the clamp screw 4, In this embodiment, the outer diameter (diameter) is mutually the same, and The difference of the outer diameter (diameter) with 1st, 2nd cylindrical part 4d, 4e becomes about 0.08-0.5 mm, for example. In addition, in this embodiment, the length of the 2nd flexible part 4g in the centerline direction of the clamp screw 4 is set longer than the 1st flexible part 4f.

In addition, the boundary between the first cylindrical portion 4d and the first flexible portion 4f twists the clamp screw 4 (screws the male screw portion 4a of the clamp screw 4 to the screw hole 6). In the state where the cutting insert 3 is clamped to the insert mounting sheet 2, as shown in FIG. 2, on the extended surface of the 1st mounting sheet wall surface 2a of this insert mounting sheet 2, or this extension is carried out. It is located in the mounting reference hole 5 from the surface. In addition, in this embodiment, the 2nd cylindrical part in the centerline direction of the clamp screw 4 in the state which clamped the clamp screw 4 similarly and clamped the cutting insert 3 to the insert mounting sheet 2, The center of 4e is set to be substantially positioned on the center of the thickness direction of the insert main body 3b, that is, on the axis O of the tool main body 1. As mentioned above, between the male-threaded part 4a and the head part 4b of the clamp screw 4 of this embodiment, the connection part, the 1st cylindrical part 4d, in the central-axis direction of the clamp screw 4, The 1st flexible part 4f, the 2nd cylindrical part 4e, and the 2nd flexible part 4f are formed continuously in order from the male-threaded part 4a side.

In addition, the through hole 3e of the insert main body 3b makes the seating surface 3d abut the mounting seat bottom surface 2c as described above, and inserts the insert main body 3b into the insert mounting sheet 2. When the male screw portion 4a starts to twist into the screw hole 6 in the seated state, the outer circumferential surface of the first and second cylindrical portions 4d and 4e and the rear end of the tool body 1 of the through hole 3e are provided. The position and the inner diameter of the centerline of the through hole 3e are set so that a slight gap is provided between the inner peripheral surfaces of the side portions. In this embodiment, the inner diameter of the through hole 3e is substantially the same as the inner diameter of the mounting reference hole 5.

Such a cutting edge cutting type cutting tool inserts the cutting insert 3 into the insert mounting sheet 2 so that the center line of the through hole 3e of the insert main body 3b is perpendicular to the axis line O as described above. The seating surface 3d by abutting the seating surface 3c with the mounting seat bottom surface 2c. Then, the clamp screw 4 is inserted into the through hole 3e from the concave conical hole 7 so as to pass through the male screw portion 4a. Is assembled by screwing into the screw hole 6.

When the male screw portion 4a starts to twist 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 head portion 4b of the clamp screw 4 is fixed. When the outer circumferential surface of the slid is in sliding contact with the conical receiving surface 7a of the concave conical hole 7, the centerline L2 of the conical receiving surface 7a is slightly smaller than the centerline L1 of the screw hole 6. Since it is eccentric to the rear end side of the tool main body 1, the clamp screw 4 starts to bend as the head part 4b falls to the rear end side of the tool main body 1.

And when the clamp screw 4 bends in this way, the outer peripheral surface of the other end side (head part 4b side) of the 2nd cylindrical part 4e is the tool main body of the through-hole 3e of the cutting insert 3. 1) The insert main body 3b is pressed against the mounting seat bottom surface 2c of the insert mounting sheet 2 in contact with the inner peripheral surface of the rear end side. At the same time, the head portion 4b of the clamp screw 4 is pressed against the conical receiving surface 7a so that the interval between the two mounting sheet wall surfaces 2a and 2b of the insert mounting sheet 2 is narrowed. The two side surfaces 3c of the jersey insert main body 3b are pressed, and the cutting insert 3 is clamped and fixed to the insert mounting sheet 2 by these pressurizations.

Here, when the clamp screw 4 starts to bend, since the outer circumferential surface of the first cylindrical portion 4d is in sliding contact with the mounting reference surface 5a on the tip side of the tool main body 1 of the mounting reference hole 5, the clamp The screw 4 is bent so that the head part 4b side may incline toward the rear end side of the tool main body 1, with the point of sliding contact with the mounting reference surface 5a on the outer circumferential surface of the first cylindrical portion 4d as a point. Goes. In other words, the portion in sliding contact with the mounting reference surface 5a of the first cylindrical portion 4d acts as the mounting reference surface on the clamp screw 4 side, and the clamp is mounted by the mounting reference surface 5a on the tool main body 1 side. Since the screw 4 is constrained on the front end side and the outer circumferential side (outer diameter direction) of the tool main body 1, no matter what direction the load is applied from the cutting edge 3a to the cutting insert 3 at the time of cutting. The cutting insert 3 can be firmly held in the insert mounting sheet 2.

Moreover, in the blade tip exchange type cutting tool of the said structure, the outer diameter is smaller than these 1st, 2nd cylindrical parts 4d and 4e between the 1st and 2nd cylindrical parts 4d and 4e of this clamp screw 4. The first flexible portion 4f is formed. For this reason, in this 1st flexible part 4f, since rigidity can be made smaller than the 1st, 2nd cylindrical part 4d, 4e in the range which is required, the clamp screw 4 can be made easy to bend. The length of the 1st flexible part 4f in the centerline direction of the clamp screw 4 which can fully acquire such an effect changes with the screw size of the clamp screw 4. For example, when the screw size of the clamp screw 4 is M8 like this embodiment, it is preferable that the said length of the 1st flexible part 4f is 100 to 500% of the length of the 1st cylindrical part 4d, Although it is preferable that it is 200 to 400%, it is not limited to this.

Moreover, since this 1st flexible part 4f is adjacent to the 1st cylindrical part 4d used as the point of the bending of the clamp screw 4 as mentioned above, it is easy to bend the clamp screw 4 more. can do. Therefore, the twisting force at the time of twisting the male screw part 4a into the screw hole 6 can be restrained by engaging a work tool, such as a wrench, with the engagement hole 4c and rotating the clamp screw 4. In addition, it becomes possible to bend the clamp screw 4 reliably and to fix the cutting insert 3 to the insert mounting sheet 2 stably.

In addition, since the outer diameter is smaller than that of the second cylindrical portion 4e which abuts the through hole 3e of the insert body 3b, the first flexible portion 4f does not come into contact with the through hole 3e. The contact area between the clamp screw 4 and the through hole 3e becomes small. Therefore, the frictional resistance between the clamp screw 4 and the through hole 3e when the clamp screw 4 abuts against the through hole 3e and presses the insert main body 3b to the rear end side of the tool main body 1. Since the cutting insert 3 can be restrained, the insert main body 3b can be prevented from shifting at the time of clamping the clamp screw 4 just before the cutting insert 3 is completely fixed, and the cutting insert 3 can be further precisely fixed. It can be attached to the road insert mounting sheet 2, and the processing precision can be improved.

In addition, in the present embodiment, a second flexible portion 4g having a smaller outer diameter than the second cylindrical portion 4e is formed between the second cylindrical portion 4e and the head portion 4b of the clamp screw 4. have. Therefore, the clamp screw 4 can be more easily bent by this second flexible portion 4g, and the contact area with the through hole 3e of the insert body 3b is further reduced to further reduce frictional resistance. Can be reduced.

Moreover, the 2nd flexible part which does not contact with the through-hole 3e between the 2nd cylindrical part 4e of the other end side (head part 4b side) of the clamp screw 4, and the head part 4b in this way, The second cylindrical portion is formed by bending of the clamp screw 4 as compared with the case where the entirety between the male screw portion 4a and the head portion 4b is a cylindrical portion in contact with the through hole 3e. The position where the outer circumferential surface of 4e is in contact with the through hole 3e can be made close to the outer circumferential surface of one end side (male screw portion 4a side) of the first cylindrical portion 4d serving as the mounting reference surface of the clamp screw 4. have. Therefore, even if the amount of deflection of the clamp screw 4 is the same, the pressing force acting on the position where the second cylindrical portion 4e contacts the through hole 3e can be made stronger by using the outer peripheral surface of the one end side as a point, whereby It is possible to secure the cutting insert 3 to the insert mounting sheet 2.

Moreover, in this embodiment, the 2nd cylindrical part 4e in the centerline direction of the clamp screw 4 in the state which clamped the clamp screw 4 and clamped the cutting insert 3 to the insert mounting sheet 2, ) Is set so as to be located approximately at the center of the thickness direction of the insert main body 3b. For this reason, the cutting insert 3 can be pressurized with a favorable balance in the thickness direction (left-right direction of FIG. 2) of the said insert main body 3b, and can be fixed to the insert mounting sheet 2 more stably. In addition, the preferable range of the length of the 2nd cylindrical part 4e in the centerline direction of the clamp screw 4 changes with the screw size of the clamp screw 4. For example, when the screw size of the clamp screw 4 is M8 as in the present embodiment, the length of the second cylindrical portion 4e is the thickness of the insert body 3b (the distance between the two side surfaces 3c). It is preferable that it is 30 to 70%, and it is more preferable that it is 40 to 60%, but it is not limited to this.

However, for example, since the outer diameter of the clamp screw 4 is originally small, the clamp screw 4 may be sufficiently bent with only the first flexible portion 4f or the contact area with the through hole 3e may be reduced. In this case, this 2nd flexible part 4g is not formed and the 2nd cylindrical part 4e may extend to the other end side as it is, and may be continued to the head part 4b. In addition, on the contrary, three or more flexible parts may be formed between the male screw part 4a and the head part 4b of the clamp screw 4.

On the other hand, in this embodiment, the boundary of the 1st cylindrical part 4d and the 1st flexible part 4f twists the clamp screw 4, and the cutting insert 3 is clamped to the insert mounting sheet 2 In the mounting reference hole 5 on the extension surface of the first mounting sheet wall surface 2a of the insert mounting sheet 2 or from this extension surface. Therefore, the first cylindrical portion 4d does not come into contact with the through hole 3e.

And since the clearance is ensured between the through-hole 3e and the 1st flexible part 4f when the clamp screw 4 is twisted in, the tip of the tool main body 1 among the outer peripheral surfaces of the 1st flexible part 4f. The part facing the side can be avoided from contacting the through hole 3e. Therefore, by this contact avoidance, it is also possible to prevent the insert main body 3b from rotating around the through hole 3e and to cause deviation in the mounting shake precision.

The angle formed by the concave conical hole 7, the center line L2, and the inner circumferential surface which can bend the clamp screw 4 adequately and sufficiently obtain the above-described effect changes depending on the screw size of the clamp screw 4. For example, when the screw size of the clamp screw 4 is M8 like this embodiment, it is preferable to set this angle to 10-40 degrees, and it is more preferable to set it to 15-35 degrees. Moreover, in the state which clamped the clamp screw 4 and clamped the cutting insert 3 to the insert mounting sheet 2, the outer peripheral surface of the conical receiving surface 7a and the head part 4b of the clamp screw 4 is carried out. The preferable range of the length in the direction of the center line L2 of the concave conical hole 7 in this contacting region also changes depending on the screw size of the clamp screw 4. For example, when the screw size of the clamp screw 4 is M8 like this embodiment, it is preferable that this length is 5 to 45% of the length of the clamp screw 4, and it is more preferable that it is 15 to 35%. .

In addition, in this embodiment, although the case where this invention was applied to the blade end exchange type ball end mill in which the rotational trajectory of the cutting edge 3a of the cutting insert 3 forms a hemispherical shape was demonstrated, also in the same edge exchange type end mill, For example, the cutting edge extends to the bottom edge extending in a direction substantially perpendicular to the axis O, and the rotational trajectory around the axis O to the outer circumferential end of the bottom edge (diameter outward end). It is also possible to apply this invention to the square end mill which consists of the outer periphery which forms the cylindrical surface centering on the center, or the radius end mill in which the arc-shaped corner blade was formed in the corner part which these bottom blade and outer periphery cross. Moreover, also in cutting tools other than an end mill, you may apply this invention to the drill of a blade exchange type, for example.

Example

Next, in the state where the boundary of the above-mentioned 1st cylindrical part 4d and the 1st flexible part 4f twists the clamp screw 4, and clamps the cutting insert 3 to the insert mounting sheet 2, The effect by being located in the mounting reference hole 5 on the extended surface of the 1st mounting sheet wall surface 2a of the insert mounting sheet 2, or from this extended surface is demonstrated with an Example. In this embodiment, when the clamp screw 4 which was based on the said embodiment was manufactured, and the cutting insert 3 was initially attached to the insert mounting sheet 2 of the tool main body 1 by this clamp screw 4, Measure the positional accuracy of the cutting edge 3a of the insert main body 3b as a reference value, and then loosen the clamp screw 4 to remove the cutting insert 3, and then mount the cutting insert 3 again. As one cycle, the mounting shake precision of the cutting insert 3 of the 10th, 100th, and 200th cycles was measured and compared with the reference value.

Here, in the clamp screw 4 according to the present embodiment, the male screw portion 4a has a secondary screw of M8 × 0.75 mm, and the diameters of the first and second cylindrical portions 4d and 4e are 8 mm and the first. The diameter of the 2nd flexible parts 4f and 4g was 7.7 mm, the largest diameter of the head part 4b was 12 mm, and the minimum diameter was 7.7 mm. The length of the first cylindrical portion 4d in the centerline direction of the clamp screw 4 is 1 mm, the length of the first flexible portion 4f is 3.08 mm, the length of the second cylindrical portion is 3.6 mm, and the second flexible portion is The length of 4g was 1.6 mm and the length of the head 4b was 7.9 mm. The inclination angle of the conical outer peripheral surface of the head part 4b with respect to the centerline direction of the clamp screw 4 was 20 degrees. The cutting insert 3 has a thickness of 7.2 mm between the two side surfaces 3c of the insert body 3b, a radius of the circular cutting edge 3a of 15 mm, and a diameter of the through hole 3e. The value was 8.008 mm. The mounting reference surface 5a of the tool main body 1 had the track shape mentioned above, and the diameter of the semicircle which forms this track shape was 8.008 mm in actual value. And while clamping the clamp screw 4 and clamping the cutting insert 3 to the insert mounting sheet 2, of the 1st cylindrical part 4d of the clamp screw 4, and the 1st flexible part 4f. The boundary was located in the mounting reference hole 5 slightly from the extended surface of the first mounting sheet wall surface 2a of the insert mounting sheet 2.

In addition, as the mounting shake precision of the cutting insert 3, the tool body (3) passes through the center of the arc-shaped cutting edge 3a in FIG. 1 when the cutting insert 3 is first mounted by the clamp screw 4. The interval between the both ends of the cutting edge 3a on a straight line perpendicular to the axis O of 1) as a reference value, and with the reference value of the interval in the 10th cycle, the 100th cycle, and the 200th cycle The difference was measured. Moreover, as a comparative example with respect to the said Example, like the fastening member of the blade tip exchangeable cutting tool of patent document 1, using the clamp screw which the whole between the external thread part and the head part became the single cylindrical part of diameter 8mm, After the same cutting insert 3 is clamped as described above, the cycle of separating is repeated, and the intervals of the 10th, 100th, and 200th cycles are measured, and the difference from the interval of the 1st cycle serving as a reference value is determined. And the mounting shake precision of the cutting insert 3 was used.

As a result, in the comparative example, the difference between the reference value in the 10th cycle was 1 µm, the difference in the 100th cycle was 12 µm, and the difference in the 200th cycle was 11 µm, so that the cutting insert 3 was attached, By repeating the separation operation, it was confirmed that a deviation occurred in the mounting shake precision. On the other hand, in the Example, the difference with the reference value in 10th cycle is 0 micrometer, and a deviation is not confirmed, The difference with a reference value is 1 micrometer also in 100th cycle and 200th cycle, and the deviation of the mounting shake precision is suppressed. I knew it was done.

Industrial availability

According to the blade end exchangeable cutting tool of the present invention, the clamp screw can be easily bent while stabilizing the pressing force of the cutting insert, and the cutting insert can be prevented from shifting at the time of tightening.

1: tool body
2: insert mounting sheet
2a, 2b: mounting sheet wall
2c: mounting sheet bottom
3: cutting insert
3a: cutting edge
3b: insert body
3c: side
3d: seating surface
3e: through hole
4: clamp screw
4a: male thread
4b: head part
4c: fastening holes
4d: first cylindrical part
4e: second cylindrical portion
4f: first flexible part
4g: second flexible part
5: mounting standard hole
5a: mounting reference plane
6: screw hole
7: concave conical hole
7a: cone receiving surface
7b: long study
O: axis of the tool body 1
L1: center line of the screw hole 6
L2: center line of the conical receiving surface 7a

Claims (3)

A cutting edge exchangeable cutting tool in which a cutting insert having an insert main body having a cutting edge is seated on a slit insert mounting sheet formed at a tip end of the tool main body and is detachably mounted by being clamped by a clamp screw.
The insert main body is provided with a seating surface which can contact the bottom surface of the insert seat of the insert mounting sheet, and a through hole through which the clamp screw is inserted through the insert main body,
Of the two mounting seat walls facing each other of the insert mounting sheet, a mounting reference hole and a screw hole are formed on one of the mounting seat walls, and a center line eccentrically toward the rear end of the tool body with respect to the center line of the screw hole on the other mounting seat wall. Conical receiving surface having a formed on the tool body front end side,
One end portion of the clamp screw is provided with a male screw portion that is screwed into the screw hole, and the other end portion has a head portion having an outer circumferential surface on the conical surface which is slidable to the conical receiving surface.
Between these male screw portions and the head portion, a first cylindrical portion whose outer peripheral surface abuts against the inner peripheral surface of the tool main body tip side of the mounting reference hole is formed on the male screw portion side, and an outer peripheral surface penetrates the insert body on the head portion side. The 2nd cylindrical part which contacts the inner peripheral surface of the tool main body rear end side in a ball | bowl is formed, Furthermore, between these 1st, 2nd cylindrical parts, The 1st flexible part whose outer diameter is smaller than the 1st, 2nd cylindrical part is formed. The blade tip exchangeable cutting tool characterized by the above-mentioned. The method of claim 1,
A second flexible part having an outer diameter smaller than that of the second cylindrical part is formed between the second cylindrical part and the head part. The method according to claim 1 or 2,
The boundary between the first cylindrical portion and the first flexible portion is on an extended surface of the one mounting seat wall surface of the insert mounting sheet or from an extended surface thereof in a state in which the clamp screw is tightened to sandwich the cutting insert. Blade end exchangeable cutting tool, characterized in that located within the mounting reference hole.

Images