JP4048678B2 - Throw-away cutter and throw-away tip - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention is a throw-away cutter (hereinafter referred to as a throwaway cutter) that is attached to the base of a blade part of a rolling tool such as an end mill and simultaneously forms a counterbore part around an opening such as a machining groove formed by the blade part. And a throw-away tip (hereinafter referred to as a tip) that is attached to the cutter and constitutes a cutting edge thereof.
[0002]
[Prior art]
For example, in the case of a steam turbine used in a power generation facility or the like, when a turbine blade is attached to its shaft, particularly when it receives a large centrifugal force, the outer peripheral surface of the shaft has a T-shape, dovetail shape, or a saw blade. A mounting groove having a cross-section such as a shape is formed, and a mounting portion having a shape that can be fitted to the cross-sectional shape of the mounting groove is formed at the base of the turbine blade, and this mounting portion is fitted into the mounting groove. It is fixed on the top. And, such a mounting groove is a cutting portion having a shape corresponding to the above-mentioned cross-sectional shape formed by this mounting groove, for example, called a Christmas cutter when the mounting groove has a sawtooth shape in cross section. As the turbine blades are mounted with an inclination with respect to the shaft center line, the outer peripheral surface of the shaft is inclined with respect to the center line accordingly. It is formed to extend.
[0003]
[Problems to be solved by the invention]
By the way, in addition to the mounting portion, the turbine blade includes a wide seat portion between the base of the blade portion and the mounting portion, and at the same time fitting the mounting portion into the mounting groove, The seating portion is seated and attached to a spot facing portion formed along the mounting groove around the opening of the mounting groove. Therefore, in addition to the mounting groove, the counterbore portion that is wider by one step around the opening of the mounting groove must be formed along the mounting groove on the outer peripheral surface of the turbine shaft. Is inclined with respect to the center line of the shaft, the spot facing portion is also inclined with respect to the center line of the shaft. Will be formed.
[0004]
However, if such a spot facing portion is formed by, for example, a common spot facing cutter, the processing by the above rolling tool for forming the mounting groove is processed in two steps, so that the processing efficiency decreases. And the molding accuracy of the mounting groove and the spot facing portion may be impaired. In particular, as described above, when the mounting groove and the counterbore are formed so as to be spirally twisted on the outer peripheral surface of the shaft, these processes are divided into two processes. It becomes extremely difficult to maintain the forming accuracy. On the other hand, the size of the mounting portion and the seating portion provided on the turbine blades varies depending on the size of the turbine blade. Because the size of the spot facings is different even between mounting grooves of the same size, for example, when a countersink cutting edge is provided at the base of the cutting tool blade part Therefore, it is necessary to prepare such rolling tools for the number of combinations of the mounting grooves and the counterbore parts having different sizes, which makes the tool management complicated and requires frequent tool replacement. As a result, the processing efficiency is further reduced.
[0005]
The present invention has been made under such a background, and in particular, when forming the mounting groove and the spot facing portion on the turbine shaft as described above, it is possible to obtain high molding accuracy and processing efficiency. Another object of the present invention is to provide a cutter capable of improving the efficiency of tool management and a chip suitable for constituting a cutting blade of the cutter.
[0006]
[Means for Solving the Problems]
To solve the aforementioned problems in order to achieve the object, a cutter of the present invention is attached to the base of the blade portion provided at the tip of the milling tool to be rotated around the axis by the cutting portion A throw-away cutter for simultaneously forming a spot facing portion around the opening of a machining groove to be formed, with the cutter body mounted on the outer periphery of an annular cutter body that can be inserted into the blade part throw-away tip having a cutting edge you back end of the blade portion in the axial direction is detachably attached, et al. is in the rotation diameter of the axis line of the cutting edge in the state of mounting the cutting insert Is made larger than the outer diameter of the blade part, and the inner periphery of the cutter body has a cross-sectional circumferential shape centered on the axis formed at the root of the blade part of the rolling tool Can be fitted to the part And Goana portion, also a root in fastenable fastening hole in the fastening part formed in the cutting portion is formed so as to be aligned in the axial direction, the chip discharge groove on the outer periphery of the blade portion is formed And a recess is formed in the outer peripheral portion of the cutter main body so as to be recessed toward the inner peripheral side and the tip side thereof reaches the inner peripheral portion of the cutter main body. The chip discharge groove communicates with the chip .
[0007]
Therefore, according to the cutter configured in this way, first, the cutter body is attached by fitting the fitting hole into the fitting portion formed at the base of the blade portion of the rolling tool. Since the groove processing by the cutting tool blade and the counterbore machining by the cutting blade of the cutter can be performed simultaneously, and the center axis of the cutter body can be made to coincide with the axis of the cutting tool with high accuracy. It becomes possible to carry out with accuracy. On the other hand, for example, the sizes of the fitting part and the fastening part are unified between the rolling tools that form grooves of different sizes, or chips of different sizes are attached to the cutter body. For example, the same cutter can be attached to a rolling tool that forms grooves of different sizes, or a counterbore portion of a different size can be formed with a single cutter body. It becomes possible to simplify tool management and tool change by using a common cutter. In order to easily attach and detach this cutter, in particular, to remove the cutter body from the rolling tool, it is related to a work tool for tightening and loosening the fastening hole portion on the outer periphery of the cutter body. It is desirable to form a mating engagement portion.
[0008]
On the other hand, the chip of the present invention is a chip that is attached to the outer periphery of the cutter body of the cutter of the present invention, and has a polygonal flat plate-shaped chip body, with one polygonal surface as the outer peripheral flank on the outer peripheral side. The rake face is attached in the direction of rotation of the rolling tool with a side face disposed around the polygonal face as a rake face, and from the corner portion facing the outer peripheral side of the tip of the rake face, An outer peripheral cutting edge is formed at the intersection ridge line portion with the outer peripheral flank surface, and a tip cutting edge is formed at the intersection ridge line portion between the rake surface and the other side surface that is directed to the distal end side of the rolling tool and serves as the distal flank surface. Each of the blades is formed, and at least the tip side portion of the rake face surrounded by the outer peripheral cutting edge and the tip cutting edge is inclined so as to be gradually depressed from the outer peripheral cutting edge toward the inner peripheral side. Things to do A. Therefore, according to such a chip, the polygonal flat plate-shaped chip body is attached to the cutter body so that the width direction thereof is along the circumferential direction of the cutter, that is, the rotation direction. In addition, the tip side portion of the rake face can be inclined, so that the radial rake angle of the outer peripheral cutting edge and the tip cutting edge can be set to the positive side, and the sharpness thereof can be set. Therefore, it is possible to promote the reduction of cutting resistance.
[0009]
DETAILED DESCRIPTION OF THE INVENTION
1 to 3 show an embodiment of the cutter of the present invention, and FIGS. 4 to 6 show an embodiment of the tip of the present invention. The cutter body of the present embodiment has a substantially circular outer shape with the cutter body 1 centered on the central axis X, and both the inner and outer peripheral parts are on the front end side (left side in FIG. 2) and the rear end side (right side in FIG. 2). It has a multi-stage shape with a diameter reduced by one step. Of these, the one-stage diameter-reduced portion of the cutter body 1 inner peripheral portion is formed in a cylindrical surface shape with the central axis X as the center to be the fitting hole portion 2 in the present embodiment. A female screw portion is formed wider than the fitting hole portion 2 in the direction of the central axis X in the inner peripheral portion on the rear end side that is enlarged by one step with respect to the fastening hole portion 3 in the present embodiment. Yes. A portion of the inner periphery of the cutter body 1 on the tip side of the fitting hole 2 is formed in a cylindrical surface shape having a diameter slightly larger than that of the fitting hole 2, and the fitting hole. 2 and the fastening hole portion 3 are also formed in a cross-sectional concave arc shape having a diameter slightly larger than the diameter of the thread valley bottom of the female screw portion of the fastening hole portion 3 over the entire circumference. A small gap is formed in the direction of the central axis X between the fitting hole 2 and the fastening hole 3 by a concave arcuate portion.
[0010]
On the other hand, the outer peripheral portion of the cutter body 1 has a plurality of (this embodiment) that is formed in a fan shape as viewed from the front end side in the central axis X direction and is recessed toward the inner peripheral side at the one-stage reduced diameter portion on the front end side. In this embodiment, four recesses 4 are formed at equal intervals in the circumferential direction, and a portion on the tip side of the recess 4 reaches the inner peripheral portion of the cutter body 1 and the fitting hole 2. Opening is made in the cylindrical surface portion having a slightly larger diameter on the distal end side, so that a cutout portion communicating with the recesses 4 is formed on the distal end side of the inner peripheral portion of the cutter body 1. . Further, as shown in FIG. 3, the edge of each recess 4 on the rear side in the tool rotation direction T has a substantially triangular shape as shown in FIG. 3, and a cross section along the central axis X is shown in FIG. A substantially L-shaped concave portion 5 is formed, and a portion of the concave portion 5 on the rear end side in the axis X direction reaches a portion whose diameter is increased by one step on the outer peripheral portion rear end side of the cutter body 1. Furthermore, the rear end of the cutter body 1 whose diameter is increased by one step is parallel to the center axis X and parallel to each other in accordance with the positions of the pair of recesses 4 and 4 located on opposite sides of the center axis X. A pair of parallel flat surfaces are formed as the engaging portions 6 and 6 in the present embodiment.
[0011]
Further, at the distal end of the cutter body 1 divided in the circumferential direction by the recesses 4..., The recesses 4, the distal end surface and the outer peripheral surface of the cutter body 1 are disposed on the rear side in the tool rotation direction T of each recess 4. The chip mounting seats 7 are respectively formed so as to open to each other, and the chips according to this embodiment as shown in FIGS. 4 to 6 are detachably mounted on these chip mounting seats 7. In this chip, the chip body 11 is formed of a hard material such as cemented carbide and forms a substantially parallelogram flat plate shape, and one of the parallelogram surfaces serves as an outer peripheral flank 12. The other parallelogram surface is a seating surface 13. Between the outer peripheral flank surface 12 and the seating surface 13, a mounting hole 14 through which the clamp screw 8 is inserted has the chip body 11 in the thickness direction. The chip main body 11 is formed so as to be symmetric with respect to the central axis of the mounting hole 14.
[0012]
Further, of the four side surfaces disposed around the outer peripheral flank 12 and the seating surface 13 of the chip body 11, a pair of long sides of the parallelogram formed by the outer peripheral flank 12 and the seating surface 13 are connected. The side surfaces are rake surfaces 15 and 15, respectively, and the remaining pair of side surfaces connected to the short sides of the parallelogram are the tip flank surfaces 16 and 15 with respect to the rake surfaces 15 and 15 that intersect the side surfaces at an acute angle, respectively. It is set to 16. Thus, the outer peripheral cutting edge 17 is perpendicular to the intersecting ridge line portion between the rake face 15 and the outer peripheral flank face 12, and the distal end cutting edge 18 is orthogonal to the intersecting ridge line portion between the rake face 15 and the distal end flank face 16. Each of the tips of the present embodiment is formed in a direction, and the tip body 11 is inverted about the central axis of the mounting hole 14 to thereby reverse the pair of rake surfaces 15 and 15 and the outer peripheral flank 12 and the pair of tips. Each pair of outer peripheral cutting edges 17 and 17 and front end cutting edges 18 and 18 formed at the intersecting ridge line portion with the front end flank surfaces 16 and 16 can be selectively used.
[0013]
Furthermore, the portion surrounded by the tip of the outer peripheral cutting edge 17 and the tip cutting edge 18 on the tip flank 16 side of the rake face 15 is the outer peripheral flank 12 as it goes from the outer flank 12 to the seating surface 13 side. And an inclined portion 19 that is inclined so as to gradually sink toward the opposite rake face 15 side, and therefore formed at the crossing ridge line portion between the inclined portion 19 and the tip flank 16. The tip cutting edge 18 is similarly formed to be inclined with an acute angle with respect to the outer peripheral flank 12, and the substantially effective cutting edge length of the outer peripheral cutting edge 17 is up to the inclined portion 19. Is done. The remaining portion of the rake face 15 and the tip flank 16 are formed in a direction perpendicular to the outer peripheral flank 12 and the seating surface 13. Furthermore, the intersection ridge line portion between the outer peripheral flank 12 and the front flank 16 is chamfered so as to intersect the outer peripheral flank 12 and the front flank 16 at an obtuse angle over the entire length, and therefore the rake The corner portion C where the outer peripheral cutting edge 17 and the front end cutting edge 18 intersect at the side ridge portion of the surface 15 is also formed in a chamfered corner shape that intersects the outer peripheral cutting edge 17 and the front end cutting edge 18 at an obtuse angle.
[0014]
The tip of the present embodiment configured as described above has the outer peripheral flank 12 of the tip body 11 directed to the outer peripheral side, the one rake face 15 directed to the tool rotation direction T side, and the rake face 15. One tip flank 16 that intersects an acute angle faces the tip side, that is, the inclined portion 19 is positioned on the tip side on the rake face 15, and is further seated on the tip mounting seat 7. The clamp screw 8 inserted through is fixed to the cutter body 1 by being screwed into a clamp screw hole (not shown), whereby the cutter of the above embodiment is configured. Here, in the state where the tip is attached to the tip mounting seat 7 in this way, the one tip flank 16 facing the tip side is inclined so as to face the rear end side toward the rear side in the tool rotation direction T. And the tip cutting edge 18 formed at the intersecting ridge line portion between the tip flank 16 and the one rake face 15 is slightly inclined toward the rear end as it goes toward the inner periphery, Further, the one rake face 15 is inclined rearward in the rotational direction T toward the rear end side, whereby the outer peripheral cutting edge formed at the intersection ridge line portion of the rake face 15 and the outer peripheral flank face 12. 17 is given a positive axial rake angle.
[0015]
FIG. 7 shows an example of a turning tool equipped with the cutter according to the embodiment configured as described above. This rolling tool is called a Christmas cutter that forms a mounting groove having a saw-toothed wall surface for mounting a turbine blade on the turbine shaft as described above. The part is formed with a wood-like blade part 22 of an outer shape Christmas tree that expands in diameter while being uneven in a saw-blade shape toward the rear end side about the central axis O of the tool body 21. Further, on the outer periphery of the blade portion 22, chip discharge grooves 23 of the same number as the recesses 4 of the cutter body 1 (that is, four in this example) are arranged at equal intervals in the circumferential direction and on the rear end side. It is formed so as to incline toward the outer peripheral side as it goes, and a cutting edge 24 is formed on the outer peripheral side ridge portion of the wall surface facing the tool rotation direction T side of the chip discharge groove 23.
[0016]
Further, a substantially cylindrical shank portion 25 is formed at the rear end portion of the tool main body 21, and a flange portion 26 having the largest outer diameter in the tool main body 21 is formed at the front end side of the shank portion 25. Has been. Furthermore, between this flange part 26 and the said blade part 22, the fitting part 27 which makes the external cylindrical surface shape whose outer diameter is larger than this blade part 22 centering on the axis line O on the blade part 22 side is formed. The fastening portion 28 having an outer diameter larger than that of the fitting portion 27 and having a male screw portion formed on the outer periphery thereof is slightly spaced from the flange portion 26 on the flange portion 26 side. Open and formed. In addition, the said chip | tip discharge groove | channel 23 ... of the blade part 22 is formed so that it may extend to the said fitting part 27, and the rear end may be rounded up to the outer periphery by the rear end side of this fitting part 27. FIG.
[0017]
The fastening hole portion 3 of the cutter body 1 is formed so that the female screw portion can be screwed into the male screw portion of the fastening portion 28 and fastened to the fastening portion 28, and the fitting hole portion 2 is formed as described above. The cutter body 1 is formed so as to be fitted to the fitting portion 27, and the cutter body 1 is inserted through the blade portion 22 from the tip side of the rolling tool, and the fitting hole portion is fastened to the fastening portion 28. By fitting 2 into the fitting portion 27, the cutter body 1 is mounted on the tool body 21 with the center axis X coaxial with the center axis O of the tool body 21 of the cutting tool. An annular plate-shaped liner 29 is interposed between the cutter body 1 and the flange portion 26. Further, in this state where the cutter body 21 is mounted, the recesses 4 of the cutter body 1 and the chip discharge grooves 23 of the tool body 21 are set to overlap each other and communicate with each other. .
[0018]
Thus, in the rolling tool equipped with the cutter having the above-described configuration, the cylindrical surface-shaped fitting hole 2 centering on the central axis X formed in the inner peripheral portion of the cutter body 1 as described above is first formed. The cutter hole 1 is fastened to the fastening portion 28 while the cutter hole 1 is fastened to the fastening portion 28 while being fitted into the fitting portion 27 having the same cylindrical surface centered on the axis O formed in the tool body 21 of the cutting tool. The cutter main body 21 is mounted at the base of the blade portion 22 of the tool main body 21, and the cutter main body 1 is placed on the tool main body 21 while the central axis X is exactly coaxial with the axis O by fitting the fitting hole portion 2 into the fitting portion 27. Can be integrated. Therefore, according to the cutter mounted on the rolling tool in this way, the machining of the counterbore portion around the opening is performed simultaneously with the machining of the mounting groove of the turbine blade on the shaft of the steam turbine by the blade portion 22 of the rolling tool. This makes it possible to improve the processing efficiency, and to give a high forming accuracy to the mounting groove and the spot facing portion thus formed.
[0019]
And on the other hand, while the said cutter is detachably attached to the tool main body 21 of the rolling tool in this way, the chip constituting the cutter blade is also detachably attached to the cutter main body 1, thereby According to this cutter, it is possible to form a counterbore part of the same size in a mounting groove of a different size or to form a counterbore part of a different size by a single cutter body 1. Management can be simplified. That is, for example, if the sizes of the fitting part 27 and the fastening part 28 are equal to each other even in the rolling tools having different sizes of the blade part 22 in accordance with the difference in the size of the mounting groove, The cutter body 1 can be mounted and a spot facing portion of the same size can be formed. Also, in a cutter mounted in this way, for example, if the chip has a different thickness from the chip body 11 The rotation diameter around the axis O of the cutting edge (outer peripheral cutting edge 17) can be made different, and the spot facings having different widths can be formed. Therefore, the number of tools can be reduced according to the cutter by being able to be mounted on various cutting tools and forming counterbore portions of different sizes by the single cutter body 1 in this way. This makes it possible to simplify the management.
[0020]
Further, even when the cutter body 1 is attached and replaced with the tool body 21 of the cutting tool having a different size of the blade portion 22 in this way, in the cutter having the above-described configuration, flat surfaces that are integral with the outer peripheral portion of the cutter body 1 and are parallel to each other. Are formed as engaging portions 6 and 6, and when the cutter body 1 is attached to or detached from the tool main body 21 of the cutting tool, for example, a working tool such as a spanner is engaged with the engaging portions 6 and 6. By rotating, the cutter body 1 can be easily tightened or loosened to the tool body 21 by tightening and loosening the fastening hole 3 and the fastening portion 28. Moreover, in this embodiment, the cutter main body 1 can be attached and detached by the operation from the outer peripheral side of the cutting tool with the work tool such as a spanner in this way, and the cutter main body 1 is the tip side of the tool main body 21 of the cutting tool. The cutter can be exchanged even when the turning tool is still mounted on the spindle of the machine tool, etc. by being inserted through the blade 22 and being attached to and detached from the root of the blade 22. Thus, the effect of further improving the working efficiency can be obtained.
[0021]
On the other hand, in the tip having the above-described configuration attached to the cutter body 1, the tip body 11 having a polygonal flat plate shape faces the outer peripheral side of the cutter body 1 with the one polygonal surface as the outer peripheral flank 12. In other words, since the width direction of the chip body 11 having a large dimension is arranged along the tool rotation direction T, it is possible to ensure high rigidity of the chip body 11 against a load acting during cutting. As a result, it is possible to promote processing with higher accuracy. In addition, the cutter body 11 is fixed by the clamp screw 8 inserted through the mounting hole 14 opened in the outer peripheral flank 12 with the outer peripheral flank 12 formed of the polygonal surface facing the outer peripheral side in this way, thereby The attachment and detachment can be performed by an operation from the outer peripheral side of the main body 1, so that the chip can be replaced even when the cutting tool with the cutter main body 1 is attached to the machine tool. And in the chip | tip of the said structure, the part enclosed by the outer peripheral cutting edge 17 and the front-end cutting edge 18 of the front end side of the rake face 15 inclined so that it might be gradually depressed toward the inner peripheral side from the outer peripheral cutting edge 17. The inclined portion 19 makes it possible to set the rake angle in the radial direction between the outer peripheral cutting edge 17 and the distal end cutting edge 18 to the more regular side, thereby improving the sharpness of these cutting edges. Thus, reduction of cutting resistance can be promoted.
[0022]
Further, particularly in the present embodiment, the tip body 11 is attached so that the axial rake angle of the outer peripheral cutting edge 17 of the tip is set to a positive angle, and the cutting resistance can be further reduced. At the same time, only the front end side of the rake face 15 is the inclined portion 19 and the rear end side is formed in a direction orthogonal to the outer peripheral flank face 12 and the seating face 13. A wall surface rising from the inclined portion 19 is formed between the portions, and this wall surface acts as a chip breaker surface, so that an effect that smooth processing of chips can be achieved is also obtained. In addition, in the above-mentioned turning tool equipped with the cutter of the present embodiment, the number of chip discharge grooves 23 formed in the blade portion 22 and the number of recesses 4 in the cutter body 1 are the same, and in the circumferential direction. Since the recesses 4 are arranged so as to overlap and communicate with each other, and the recess 4 defines a notch that reaches the inner periphery of the cutter body 1, that is, the outer periphery of the blade 22, the blade 22 It is also possible to discharge the chips generated by the cutting blade 24 through the recess 4, and the advantage that a smoother chip treatment can be achieved.
[0023]
In the cutter of this embodiment, the small-diameter fitting hole 2 is formed on the front end side of the cutter body 1 and the large-diameter fastening hole 3 is formed on the rear end side. The fastening hole 3 may be formed on the front end side of the cutter body 1 with a small diameter, and the large-diameter fitting hole 2 may be formed on the rear end side. In this case, the tool body 21 of the rolling tool is used. The fitting part 27 and the fastening part 28 are also formed opposite to each other. In the present embodiment, the fastening hole 3 is wider than the fitting hole 2 in the central axis X direction, but conversely, the fitting hole 2 is wider than the fastening hole 3. Also good.
[0024]
【The invention's effect】
As described above, according to the cutter of the present invention, it is possible to improve the processing efficiency by performing spot facing processing around the opening of the groove with high accuracy simultaneously with the groove processing by the rolling tool, Even when grooves or counterbore portions of different sizes are formed, the tool body can be shared to simplify tool management. Moreover, if the engaging part which can be engaged with a working tool is formed in the outer peripheral part of this cutter main body, attachment / detachment of a cutter main body can be made easy and improvement of working efficiency can be aimed at. Furthermore, according to the chip of the present invention, it is possible to ensure high rigidity by being attached to the cutter, and it is possible to process the counterbore part with higher accuracy and to cut by tilting at least the tip side of the rake face. The sharpness of the blade can be improved, and the reduction of cutting resistance can be promoted.
[Brief description of the drawings]
FIG. 1 is a front view showing an embodiment of a cutter of the present invention.
FIG. 2 is a side sectional view of the embodiment shown in FIG.
FIG. 3 is a side view showing the periphery of the chip of the embodiment shown in FIG. 1;
FIG. 4 is a plan view showing an embodiment of a chip of the present invention.
5 is a side view as viewed in the direction of the arrow Y in FIG. 4. FIG.
6 is a side view in the direction of arrow Z in FIG.
7 is a partially broken side view showing an example of a rolling tool equipped with the cutter according to the embodiment shown in FIGS. 1 to 3. FIG.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Cutter body 2 Fitting hole part 3 Fastening hole part 4 Recess 6 Engagement part 7 Tip mounting seat 8 Clamp screw 11 Tip body 12 Outer peripheral flank face 15 Rake face 16 Front flank face 17 Outer peripheral edge 18 End cutting edge 19 Inclination Part 21 Tool body 22 Blade part 23 Chip discharge groove 27 Fitting part 28 Fastening part X Center axis O of cutter body 1 Center axis T of tool body 21 Tool rotation direction C Corner part of chip body 11

Claims (3)

A throw-away type that is attached to the base of a blade provided at the tip of a turning tool that rotates about an axis and simultaneously forms a counterbore around the opening of a machining groove formed by the blade. A cutter,
The outer periphery of the insertable annular cutter body to the edge portion, to be indexable insert in a state of mounting the cutter body with a cutting edge you back end of the blade portion in the axial direction is detachably mounting et is, while the rotation diameter of the axis around the cutting edge in the state of mounting the cutting insert is greater than the outer diameter of the blade portion, the inner periphery of the cutter body, the milling tool Can be fastened to a fitting hole that can be fitted to a fitting part that has a circular cross-section around the axis formed at the base of the blade part, and a fastening part that is also formed at the base of the blade part And a fastening hole portion is formed so as to be aligned in the axial direction ,
A chip discharge groove is formed on the outer periphery of the blade part, and a recess is formed in the outer peripheral part of the cutter body so as to be recessed toward the inner peripheral side, and the tip side thereof reaches the inner peripheral part of the cutter body. The throwaway cutter characterized in that the recess and the chip discharge groove are communicated with each other in a state where is mounted . 2. The throwaway according to claim 1, wherein an engagement portion is formed on an outer peripheral portion of the cutter main body so as to be engageable with a working tool for loosening and tightening the fastening hole portion to the fastening portion. Expression cutter. A throw-away tip attached to the outer periphery of the cutter body of the throw-away cutter according to claim 1 or 2, comprising a polygonal plate-like tip body, with one polygonal surface as an outer peripheral flank. From the corner portion facing the outer peripheral side of the rake face, the rake face is attached in the direction of rotation of the rolling tool with one side face arranged around the polygonal face as a rake face. The outer peripheral cutting edge is at the intersection ridge line portion between the rake face and the outer peripheral flank surface, and the intersection ridge line portion between the rake face and the other side surface that is the tip flank surface facing the tip end side of the rolling tool. Each of the tip cutting edges is formed, and at least the tip side portion of the rake face surrounded by the outer peripheral cutting edge and the tip cutting edge gradually sinks from the outer peripheral cutting edge toward the inner peripheral side. Cutting inserts, characterized in that it is allowed to urchin inclined.

Images