JP4752324B2 - Pin mirror cutter - Google Patents

Description

  The present invention relates to a pin mirror cutter for processing a crankshaft used for, for example, a reciprocating internal combustion engine.

  Conventionally, for example, a so-called internal type pin mirror cutter as disclosed in Patent Document 1 is known. In this pin mirror cutter, a plurality of first insert mounting seats are formed on the inner peripheral surface of the cutter body that is rotated around an axis, and the inner peripheral surface side is formed on both side surfaces of the cutter main body. A plurality of second chip mounting seats are formed, and the first and second insert mounting seats are respectively mounted with the same type of cutting insert.

  In this cutting insert, a total of eight cutting edges are formed on the intersecting ridge line portion between the pair of side surfaces opposed to each other and the upper and lower surfaces of the insert body, which are substantially parallelogram flat plate shapes. In the other pair of side surfaces different from the side surfaces, the region on the obtuse corner portion side of the insert body is cut off so as to increase the corner angle, so that the other pair of side surfaces is composed of two wall surfaces. Thus, it has a mountain shape that is convex outward of the insert body. Further, each of the connecting portions to the other pair of side surfaces on the upper and lower surfaces of the insert body is chamfered into a convex curved surface.

  The cutting insert mounted on the first insert mounting seat has an axial rake angle (axial rake angle) with one cutting edge formed at the acute corner of the insert body having a substantially parallelogram flat plate shape. Pin blade (outer periphery) that is projected from the inner peripheral surface of the cutter body so that the angle and radial rake angle (radial rake angle) become a negative angle, and processes the outer peripheral surface of the pin portion (shaft portion) of the crankshaft Blade). In addition, the cutting insert mounted on the second insert mounting seat has an axial rake angle (axial rake angle) with one cutting edge formed at an obtuse corner portion of the insert body having a substantially parallelogram flat plate shape. Is a web blade (shoulder blade) that protrudes from the side of the cutter body so that the negative rake angle and radial rake angle (radial rake angle) are also negative angles, and processes the side of the counterweight part of the crankshaft. ing.

In such a pin mirror cutter, the same type of cutting inserts are mounted on the first and second insert mounting seats, so that cutting blades formed in a total of eight locations with one cutting insert are used for cutting. Thus, the tool cost can be reduced. And, by using a cutting insert having a substantially parallelogram flat plate-like insert body having the other pair of side surfaces as described above, the pin blade of the cutting insert to be mounted on the first insert mounting seat The axial rake angle given to the cutting edge is set to a positive angle to reduce cutting resistance.
JP 2002-46009 A

  However, in the pin mirror cutter described in Patent Document 1, the cutting insert attached to the second insert mounting seat as the web blade has a radial rake angle of −20 ° which is large on the negative angle side. Because it is set, chips generated by the cutting blade are not smoothly guided to the outer peripheral side of the cutter body, and the inside of the chip pocket adjacent to the insert mounting seat is tangent to a circle centering on the axis of the cutter body. In the direction, that is, in a side view, it flows right sideward and is guided again forward in the rotational direction of the cutting blade, and may be caught by the web blade.

  Then, when the bite of the chips occurs in this way, the cutting insert that is the web blade is damaged, such as a chip, and its life is consumed. As described above, the eight cutting blades are used for cutting and the tool cost is reduced. It becomes impossible to aim at reduction of. In addition, if the chips flow out sideways in this way, also in the cutter body, clogging of chips is likely to occur, and since the chips flow by rubbing the same part of the inner wall surface of the chip pocket, this part is deeply swamped, There is also a problem that the lifetime is shortened. Further, in the crankshaft as a workpiece, burrs are generated in the counterweight portion cut by the web blade, and thus deburring work is necessary after cutting work by the pin mirror cutter.

  The present invention has been made under such a background, and the pin mirror cutter as described above, particularly a pin mirror cutter to which a cutting plate having a rectangular flat plate shape is attached and its eight cutting blades can be used. The purpose of the present invention is to provide a pin mirror cutter capable of preventing the biting of chips, clogging of chips, chipping of chip pockets, etc., and extending the life of both the cutting insert and the cutter body.

In order to solve the above problems and achieve such an object, according to the present invention, a first insert mounting seat is provided on a peripheral surface of a cutter body having a substantially annular shape or a substantially disc shape rotated about an axis. A second insert mounting seat is formed on the peripheral surface side of the side surface of the cutter body, and the first and second insert mounting seats each have a cutting insert having the same shape and the same size. It is a pin mirror cutter that can be attached, and the cutting insert has a pair of side surfaces along the thickness direction of the insert body having a rectangular flat plate shape as a rake face, and a ridge portion of these rake faces. , one has a total of eight of the cutting for the insert body is formed, the in the first insert mounting seat, one being the thickness direction mounted toward a radial direction of the cutter body In the second insert mounting seat, the thickness direction is directed to the axial direction of the cutter body so that the axial rake angle of the cutting blade is a negative angle up to -8 °, and the The cutting blade is mounted so that the radial rake angle is a negative angle of up to -15 °.

  Therefore, in the pin mirror cutter configured in this way, the cutting insert attached to the second insert mounting seat on the side surface of the cutter body and serving as a web blade has a negative radial rake angle of the cutting blade. Since the angle is set to -15 °, the chips generated by the web blade can be surely guided in the radial direction of the cutter body and discharged smoothly, preventing damage to the cutting insert due to the biting of the chips. The lifetime can be extended. In addition, since smooth chip discharge performance is obtained in this way, it is possible to prevent chip clogging and chipping of the inner wall surface of the chip pocket and to generate burrs in the counterweight portion cut by the web blade. Therefore, high-quality and efficient processing can be achieved.

  Here, as a cutting insert that can be used as a web blade in this way and the radial rake angle of the cutting blade can be a negative angle up to −15 °, the insert body has a substantially isosceles trapezoidal flat plate shape. The side face along the oblique side portion of the insert body and the thickness direction of the insert main body may be a rake face. That is, in such a cutting insert, out of cutting blades extending from a total of eight corner portions of the side surface as the rake face, four cutting blades positioned on the obtuse corner portion side of the isosceles trapezoidal surface are cut into the cutting edge. When the insert is mounted on the second insert mounting seat, it can be used as a cutting blade, that is, a web blade, and its radial rake angle can be set to a negative angle of up to -15 °.

  On the other hand, the four cutting blades positioned on the acute corner side of the isosceles trapezoidal surface can be used as cutting blades when the cutting insert is attached to the first insert mounting seat, that is, pin blades. Since the first insert mounting seat can be mounted so that the axial rake angle of the cutting blade is a positive angle, a total of eight cutting blades can be used with one cutting insert. Cutting resistance when used as a pin blade can be reduced.

  On the other hand, as the cutting insert, an insert body having a substantially rectangular flat plate shape can be used. In this case, the cutting insert has its cutting edge in the first insert mounting seat, that is, The pin blade is mounted so that the axial rake angle is a negative angle. However, such a cutting insert has a negative rake of up to -8 ° so that the radial rake angle of the cutting edge, that is, the web edge is closer to the positive angle side in the second insert mounting seat. Therefore, the chips can be guided more reliably in the radial direction of the cutter body, and it is possible to prevent the occurrence of chipping and chip clogging.

  1 to 3 show a first embodiment of the present invention. The pin mirror cutter according to the present embodiment is of an internal type, and the cutter body 10 is centered on the axis O rotated around the axis O as shown in the enlarged views of the main part in FIGS. It has a generally annular shape. In the cutter body 10, a plurality of first insert mounting seats 13 are formed on the inner circumferential surface 11 facing the radially inner circumferential side at substantially equal intervals along the circumferential direction of the cutter body 10. A plurality of second insert mounting seats 14 are substantially equal along the circumferential direction of the cutter main body 10 on the inner peripheral surface 11 side of both side surfaces 12A, 12B facing the outer side in the axis O direction of the main body 10. It is formed at intervals.

  Among these, the plurality of first insert mounting seats 13 are arranged closer to one side surface 12A of both side surfaces 12A and 12B of the cutter body 10 and closer to the other side surface 12B. Are alternately arranged in the circumferential direction of the cutter body 10. Further, in the circumferential direction of the cutter body 10, the plurality of second insert mounting seats 14 formed on one side surface 12A thereof are formed on the inner peripheral surface 11 near the other side surface 12B. Each of the plurality of second insert mounting seats 14 formed on the other side surface 12B of the cutter main body 10 is also disposed near the one side surface 12A. Each of the plurality of first insert mounting seats 13... Formed on the peripheral surface 11 is disposed slightly behind the cutter rotation direction T. Further, a tip pocket 11A for discharging chips generated at the time of machining is formed on the front side in the cutter rotation direction T of each insert mounting seat 13.

  The cutting insert attached to the first and second insert mounting seats 13, 14... Has an insert body 20 formed of a hard material such as cemented carbide, and in this embodiment, as shown in FIG. Are formed in a substantially isosceles trapezoidal flat plate shape, that is, in the thickness direction of the insert body 20 (in FIG. 3A, the direction perpendicular to the drawing. In FIG. 3B, the left-right direction. FIG. 3C). The upper and lower surfaces 21 and 21 are substantially isosceles trapezoidal parallel to each other in the vertical direction), and a pair of side surfaces 22 extending along the oblique side of the isosceles trapezoid formed by the upper and lower surfaces 21 and 21 and the thickness direction. , 22 and a pair of side surfaces 23, 23 extending in parallel with each other along the upper and lower bases of the isosceles trapezoid, and the oblique side of the isosceles trapezoid is formed from either the upper base or the lower base. Has also been long.

  Therefore, the insert body 20 has side surfaces 22 and 22 and one side surface (an isosceles trapezoidal upper and lower bases) at one end in the longitudinal direction of the upper and lower surfaces 21 and 21 (the left end in FIG. 3A). A pair of acute corner portions 24A and 24A that intersect at an acute angle with each other at the same angle, and the other end in the longitudinal direction opposite to this (the right end portion in FIG. 3A) ), And a pair of obtuse corner portions 24B, 24B in which the side faces 22, 22 and the other side face (the side face along the shorter one of the upper and lower bases of the isosceles trapezoid) intersect at an obtuse angle at the same angle. Will be formed. Here, the angle α of the acute corner portions 24A and 24A is preferably in the range of 75 to 85 °, and therefore the angle β of the obtuse corner portions 24B and 24B is preferably in the range of 95 to 105 °. . An insertion hole 20 </ b> A through which a clamping screw for clamping the cutting insert to the insert mounting seats 13, 14 passes through the insert body 20 in the thickness direction of the insert body 20. It is formed as follows.

  Here, each of the side surfaces 22 and 22 is constituted by one flat surface that is parallel to the thickness direction of the insert main body 20, and therefore, the upper and lower surfaces 21 and 21 intersect perpendicularly at the oblique sides. Thus, the rake face of the cutting insert is used. On the other hand, the side surfaces 23, 23 are formed by flat surfaces parallel to the thickness direction at the center in the thickness direction. The bottom and lower bottom portions are formed so as to form convex curved surfaces from the upper and lower surfaces 21, 21 to the side surfaces 23, 23.

  As shown in FIG. 3C, a pair of acute corner portions 24A and 24A on the upper and lower surfaces 21 among the convex curved surfaces formed on the intersecting ridge line portions of the upper and lower surfaces 21 and 21 and the side surfaces 23 and 23. The intersecting ridge line portion that connects the two is a curved portion 21A having a substantially arc-shaped cross section that smoothly contacts the upper and lower surfaces 21 and 23, and connects the pair of obtuse corner portions 24B and 24B of the upper and lower surfaces 21 to each other. The intersecting ridge line portion is a curved surface portion 21B having an arcuate cross section that smoothly touches the upper and lower surfaces 21 and intersects the side surface 23 with an obtuse angle.

  In the insert body 20, cutting edges are formed at intersection ridges between the pair of side surfaces 22 and 22 and the upper and lower surfaces 21 and 21. More specifically, a total of eight curved blades 25A having a substantially convex curve shape are formed at the intersecting ridgeline portions of the curved surface portions 21A, 21A, 21B, 21B and the pair of side surfaces 22, 22 on the upper and lower surfaces 21, 21 respectively. On the other hand, the curved blades 25A at both ends thereof are formed on the intersecting ridges between the portions of the upper and lower surfaces 21, 21 excluding the curved surface portions 21A, 21A, 21B, 21B and the pair of side surfaces 22, 22. A total of four straight blades 25B that form a substantially straight line so as to be in smooth contact are formed, and a total of eight curved blades 25A and a total of four straight blades 25B are formed in one cutting insert.

  The cutting inserts configured as described above are detachably attached to a plurality of first and second insert attachment seats 13, 14, respectively, of the cutter body 10. Among these, with respect to the first insert mounting seat 13, the cutting insert substantially matches the thickness direction of the insert body 20 toward the radial direction of the cutter body 10, and is one of the pair of side surfaces 22, 22. The screw is attached by being clamped by a clamp screw 15 that is inserted into the insertion hole 20A of the insert body 20 so that the one is a rake face toward the front side of the cutter rotation direction T.

  The cutting insert to be mounted on the first insert mounting seat 13 in this way is one of the eight curved blades 25A..., One curved blade 25A formed at the acute corner portion 24A, and the first insert mounting seat 13. Is positioned on the side surface 12A or the side surface 12B side of the cutter body 10 to which the cutter blade 10 is moved, and protrudes outward in the direction of the axis O from the inner peripheral surface 11, and the linear blade 25B connected to the curved blade 25A is respectively cut from the curved blade 25A. 10 is extended from the inner peripheral surface 11 to the inner side in the radial direction so as to extend inward in the direction of the axis O. Further, the cutting inserts attached to the first insert mounting seats 13 near the side surface 12A and the side surface 12B are overlapped with each other on the inner side in the direction of the axis O of the linear blade 25B in the rotation locus around the axis O. A pin portion (shaft) of the crankshaft is formed by a curved blade 25A and a straight blade 25B of the cutting insert which are formed in one straight line substantially parallel to the axis O and are mounted on the plurality of first insert mounting seats 13. The pin blade which processes the outer peripheral surface of (part) is formed.

  Further, the curved surface portion 21A and the upper and lower surfaces 21 connected to the rear side in the cutter rotation direction T of the curved blade 25A and the straight blade 25B, which are the pin blades, are directed toward the outer peripheral side in the radial direction as going to the rear side in the cutter rotation direction T. While being inclined, the curved surface portion 21A and the side surface 23 connected to the curved surface portion 21A are also inclined toward the inner side in the axis O direction toward the rear side in the cutter rotation direction T. Further, relief is given to the curved surface portion 21A and the upper and lower surfaces 21 that form the flank of the straight blade 25B. Further, since the side surface 22 and the upper and lower surfaces 21 which are rake faces intersect perpendicularly, the side surface 22 is inclined to the front side in the cutter rotation direction T as it goes to the outer peripheral side in the radial direction. The radial rake angle (radial rake angle) RP of the curved blade 25A and the straight blade 25B, which are pin blades, is set to a negative angle (for example, −8 °).

  On the other hand, the axial rake angle (axial rake angle) AP of the curved blade 25A and the straight blade 25B, which are pin blades, is the axis line from the curved blade 25A toward the straight blade 25B as described above. A positive angle is set (for example, 5 °) by inclining toward the rear side of the cutter rotation direction T as it goes inward in the O direction. That is, the cutting insert in the pin mirror cutter of the present embodiment has a side surface 22 that forms a rake face and the side surface 23 that is directed outward in the direction of the axis O of the cutter body 10 when attached to the first insert mounting seat 13. Since the angle α is intersected via the acute corner portion 24A in the range of 75 to 85 °, the curved surface portion 21A that forms the flank of the curved blade 25A that is a pin blade and the side surface 23 that is connected to the curved surface portion 21A. Even if relief is given, the axial rake angle AP of the curved blade 25A and the straight blade 25B, which are pin blades, can be set to a positive angle.

  On the other hand, the cutting insert configured as described above has the thickness direction of the insert main body 20 substantially aligned with the second insert mounting seat 14 in the direction of the axis O of the cutter main body 10 and is also a pair. One of the side surfaces 22 and 22 is raked with a clamp screw 15 inserted through the insertion hole 20A of the insert body 20 so as to be a scooping surface toward the front side of the cutter rotation direction T. Here, the cutting insert to be mounted on the second insert mounting seat 14 has one curved blade 25A formed at the obtuse corner portion 24B among the eight curved blades 25A ... as the side surface 12A of the cutter body 10. Alternatively, it is protruded from the side surface 12B outward in the direction of the axis O, and is attached so as to overlap the outer side of the cutter blade 10 in the direction of the axis O of the curved blade 25A, which is the pin blade, in the rotation trajectory around the axis O. The curved blade 25A arranged in such a protruding state is a web blade for processing the side surface of the counterweight portion of the crankshaft.

  Further, the cutting insert attached to the second insert mounting seat 14 in this way is inclined so that the upper and lower surfaces 21 directed outward in the axis O direction are directed inward in the axis O direction toward the outer peripheral side of the cutter body 10. Thus, the straight blade 25B connected to the curved blade 25A, which is a web blade, is given relief and is not used for cutting. Further, the curved surface portion 21B connected to the cutter rotation direction T rear side of the curved blade 25A, which is the web blade, is also inclined so as to go to the inner side of the axis O direction and the radial outer periphery side toward the rear side of the cutter rotation direction T. The escape is given to this curved surface portion 21B which is the flank of the curved blade 25A which is a web blade. Therefore, the axial rake angle (axial rake angle) AW of the curved blade 25A used as the web blade is inclined so that the curved blade 25A moves forward in the cutter rotation direction T as it goes inward in the axis O direction. Therefore, the negative angle is set (for example, −7 °).

  Further, the radial rake angle (radial rake angle) RW of the curved blade 25A used as the web blade is inclined so that the curved blade 25A moves toward the front side of the cutter rotation direction T as it goes toward the radially outer peripheral side. However, the magnitude is set to a range up to −15 °, and in the present embodiment, it is set to −15 °. That is, the cutting insert in the pin mirror cutter of the present embodiment is the web blade because the angle β of the obtuse corner portion 24B on which the curved blade 25A as the pin blade is formed is 95 to 105 °. Even if necessary clearance is ensured for the curved surface portion 21B connected to the curved blade 25A, the radial rake angle RW of the curved blade 25A can be set to a negative angle of up to -15 °.

  The pin mirror cutter having such a configuration is attached to the cutter attachment portion of the processing machine so that the axis O of the cutter body 10 coincides with the main axis, and the crankshaft spanned by the chuck is connected to the inside of the cutter body 10. In a state of being inserted into the peripheral portion, the cutter blade is rotated in the cutter rotation direction T around the axis O of the cutter body 10 and revolved around the axis of each pin portion of the crankshaft, and is used as the pin blade of the cutting insert. By cutting the curved blade 25A, the straight blade 25B, and the curved blade 25A, which is a web blade, the crankshaft, in particular, the periphery of the pin portion is processed into a predetermined shape.

  Here, in the cutting insert, the curved blade 25A and the straight blade 25B formed on the acute corner portion 24A side as described above are used for cutting when the cutting insert is attached to the second insert mounting seat 14. On the contrary, the curved blade 25A formed on the obtuse corner portion 24B side is not used for cutting when mounted on the first insert mounting seat 13, and such curved blades 25A, 25A and Two sets of straight blades 25B are provided on one side surface 22, and a pair of such side surfaces 22 are provided. Therefore, for one insert body 20, there are four curved blades 25A and four straight blades 25B that can be used as pin blades. A total of eight cutting blades are formed, including a pair and four curved blades 25A that can be used as web blades. Therefore, the cutting insert is the one insert body 20 and the first insert mounting seat 13 near the side surface 12A and the side surface 12B of the cutter body 10 twice each, and the cutting insert on the side surface 12A side and the side surface 12B side. Even two insert mounting seats 14 can be used a total of eight times, two times each.

  And in the pin mirror cutter of the said structure which attached such a cutting insert, the radial rake angle RW of the curved blade 25A used as the web blade of the cutting insert attached to the said 2nd insert mounting seat 14 is negative. Although it is an angle, the angle is set to −15 °. Therefore, the chips generated by the curved blade 25A, which is the web blade, are surely moved along the side surface 22 which is the rake face of the curved blade 25A. It can be guided and discharged in the radial direction (in this embodiment, the outer peripheral side).

  However, when the radial rake angle RW of this web blade exceeds -15 ° and is set to the negative angle side, the second insert mounting is the same as the pin mirror cutter described in Patent Document 1. Chips flow in the chip pocket 11A adjacent to the seat 14 along the tangential direction of the circle with the axis O as the center in a side view, to the curved blade 25A as a web blade and the linear blade 25B connected to the curved blade 25A. The cutting insert may cause damage to the cutting insert, the inner wall surface of the chip pocket 11A may be removed, or burrs may be generated on the crankshaft to be processed. In this way, the chips can be reliably guided in the radial direction of the cutter body 10, so that such chip biting, chip pocket 11 </ b> A punching, crankshaft bar It does not occur, such as.

  For this reason, while preventing damage to the cutting insert, it is possible to reliably use the cutting blade 8 times, and it is possible to extend the life of the cutter body 10 and to further reduce the tool cost. The crankshaft machined by this pin mirror cutter can also be processed with high quality without burrs, preventing the situation where machining efficiency is impaired due to deburring work, and the crankshaft Processing efficiency can be improved.

  Moreover, in this embodiment, the cutting insert attached to such a pin mirror cutter has the substantially isosceles trapezoid flat plate-like insert main body 20, and the hypotenuse part of the upper and lower surfaces 21 and 21 which make this isosceles trapezoid and insert Side surfaces 22 along the thickness direction of the main body 20 are rake faces. And when this cutting insert is attached to the 1st insert mounting seat 13, since the axial rake angle AP of the curved blade 25A used as a cutting blade (pin blade) and the linear blade 25B is made into a positive angle. Thus, it is possible to reduce the cutting resistance and promote a highly accurate and stable crankshaft processing.

  Further, in this embodiment, such a cutting insert is provided on the second insert mounting seat 14 on the side surfaces 12A and 12B of the cutter body 10 with the obtuse corner portion 24B side directed toward the inner peripheral side of the cutter body 10 and the outer periphery. It is attached in such a direction that the distance between the side faces 22 increases as it goes to the side, that is, it is mounted so as to form an arc centered on the axis O. For this reason, the second insert mounting seat 14 to which such a cutting insert is attached can be prevented from increasing in the circumferential direction particularly on the inner peripheral side, and the strength and rigidity of the cutter body 10 are improved and adjacent to each other. There is also an advantage that the cutting insert can be securely attached at a predetermined position by preventing interference with the first insert mounting seat 13.

  However, in the first embodiment, the insert body 20 is thus formed in the shape of an isosceles trapezoidal plate. However, the radial rake angle of the cutting blade used as the web blade is 0 ° to −15 ° (however, 0 ° 4 to 7, the insert body 30 has a rectangular flat plate shape as in the pin mirror cutter according to the second embodiment of the present invention. A cutting insert may be used. In the second embodiment, parts common to the first embodiment such as the cutter body 10 are assigned the same reference numerals to simplify the description.

  That is, the cutting insert in the present embodiment is formed so that the insert main body 30 has a substantially square flat plate shape, the upper and lower surfaces 31 and 31 forming the square, and the periphery of the insert main body 30 along the thickness direction of the insert main body 30. Of the four side surfaces 32, 32, 33, 33, the side surfaces 32, 32 and the other pair of paired surfaces are formed on the intersecting ridge line portion with the pair of side surfaces 32, 32, which are parallel to each other and located on opposite sides. A cutting edge is formed that has a curved curved edge 35A located on the side of the corner where the side surfaces 33 intersect with each other, and a straight edge 35B in which these curved edges 35A smoothly contact at both ends. In the cutting insert in the present embodiment, the corner portions of the side surfaces 32 and 33 are all right angles, and the intersecting ridge line portion between the side surfaces 33 and 33 and the upper and lower surfaces 31 and 31 is matched with the convex curve formed by the curved blade 35A. The curved surface part.

  In the cutting insert in the second embodiment as described above, the first insert mounting seat 13 on the inner peripheral surface 11 of the cutter body 10 has a curved blade 35A and a straight blade 35B connected to the curved blade 35A. It is made to project so as to be used for cutting. Here, the radial rake angle RP of the curved blade 35A and the straight blade 35B used as the pin blades is a negative angle (for example, −8 °) as in the first embodiment, whereas in the first embodiment, a positive angle. In the present embodiment in which the corner portion is a right angle, the axial rake angle AP is also a negative angle (for example, 6 °) as shown in FIG.

  On the other hand, in the second insert mounting seat 14 on the side surfaces 12A and 12B of the cutter body 10, the cutting insert is not subjected to cutting when it is mounted on the first insert mounting seat 13. The curved blade 35A is projected as a web blade and attached. The curved blade 35A, which is the web blade, has an axial rake angle AW substantially equal to the negative angle (eg, −6 °) of the first embodiment, whereas a radial rake angle RW is Since the corner portion is a right angle from the obtuse angle corner portion 24B of the first embodiment, even if it is a negative angle, it is set in a range up to −8 ° closer to the positive angle side. In this embodiment, −8 ° is set. It is °.

  Therefore, also in the pin mirror cutter of the second embodiment, first, on each of the pair of side surfaces 32, 32 of the insert body 30, there are two sets of curved blades 35A and straight blades 35B which are pin blades, respectively. A curved blade 35A that is a web blade is formed, that is, a single insert body 30 is provided with a total of eight cutting blades that can be used four times as a pin blade and four times as a web blade. Can be reduced. Moreover, since the insert main body 30 itself is square flat plate shape, the advantage that the manufacture is comparatively easy can also be acquired.

  Further, in the second embodiment, the radial rake angle RW of the curved blade 35A that is the web blade of the cutting insert attached to the second insert mounting seat 14 is closer to a positive angle as described above. Since the negative angle is up to 8 °, the side surface 32, which is a rake face connected to the curved blade 35A, may be brought closer to the state of facing the front in the cutter rotation direction T along the radial direction of the cutter body 10. it can. For this reason, the chips generated by the curved blade 35A, which is the web blade, are more reliably guided in the radial direction of the cutter body 10 along the side surface 32, which is the rake face, and are smoothly discharged. Therefore, according to the present embodiment, it is possible to more effectively prevent the biting of chips, the chipping of the inner wall surface of the chip pocket 11A, the occurrence of burrs on the crankshaft, and the like.

  In each of the above-described embodiments, the present invention is described as being applied to a so-called internal pin mirror cutter. However, the present invention is not limited to this, and the diameter of the disc-shaped cutter body is not limited thereto. A plurality of first insert mounting seats are formed on the outer peripheral surface facing the outer peripheral side in the direction, and a plurality of second insert mounting seats are formed on the outer peripheral surface sides of both side surfaces facing the axial direction. For example, the present invention may be applied to a so-called external pin mirror cutter in which cutting inserts similar to those in the first and second embodiments are mounted on the first and second insert mounting seats, respectively.

It is the elements on larger scale seen from the side surface 12A side in the cutter main body 10 which shows the principal part of the 1st Embodiment of this invention. It is the elements on larger scale which looked at the internal peripheral surface 11 in the cutter main body 10 from the axis line O side which shows the principal part of the 1st Embodiment of this invention. (A) of the cutting insert with which the 1st Embodiment of this invention is mounted | worn is a top view, (b) is a side view of the arrow A direction view in (a), (c) is the arrow B in (a). It is a side view of the direction view. It is the elements on larger scale which looked at the 1st insert seat 13 periphery from the side 12A side which shows the principal part of the 2nd Embodiment of this invention. It is the elements on larger scale which looked at the 2nd insert mounting seat 14 periphery from the side surface 12A side which shows the principal part of the 2nd Embodiment of this invention. It is the elements on larger scale which looked at the inner peripheral surface 11 around the 1st insert mounting seat 13 from the axis line O side which shows the principal part of the 2nd Embodiment of this invention. It is the elements on larger scale which looked at the inner peripheral surface 11 around the 2nd insert attachment seat 14 which shows the principal part of the 2nd Embodiment of this invention from the axis line O side.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Cutter main body 11 Inner peripheral surface 12A, 12B of cutter main body 10 Side surface of cutter main body 13 1st insert mounting seat 14 2nd insert mounting seat 20,30 Insert main body 21,31 Upper and lower surfaces 22 of insert main bodies 20,30 22 , 32 Side surface of insert body 20, 30 as rake face 24 A Insert corner 20 acute angle corner 24 B Insert body 20 obtuse corner 25 A, 35 A Curved blade 25 B, 35 B Straight edge O Cutter body 10 axis T Cutter body 10 Rotational direction α Angle of acute corner portion 24A β Angle of obtuse corner portion 24B AP Curved blades 25A and 35A used as pin blades and axial rake angle of straight blades 25B and 35B Curved blades 25A and 35A used as RP pin blades and Radial array of straight blades 25B and 35B Curve blade 25A, which is the corner AW web blade, curve blade 25A, which is the axial rake angle RW web blade of 35A, 35A radial rake angle of

Claims (3)

A first insert mounting seat is formed on the peripheral surface of the cutter main body that is formed in a substantially annular shape or a substantially disk shape rotated around the axis, and a second insert mounting seat is formed on the peripheral surface side of the side surface of the cutter main body. The first and second insert mounting seats are pin mirror cutters in which cutting inserts each having the same shape and size are detachably attached to each other ,
In the cutting insert, a pair of side surfaces along the thickness direction of the insert body having a rectangular flat plate shape is a rake face, and a total of eight cutting blades for one insert body at a side ridge portion of these rake faces. In the first insert mounting seat, the thickness direction is attached to the radial direction of the cutter body, while in the second insert mounting seat, the thickness is The axial rake angle of the cutting blade is a negative angle up to -8 °, and the radial rake angle of the cutting blade is a negative angle up to -15 °. A pin mirror cutter characterized by being attached to be.   The insert body has a substantially isosceles trapezoidal flat plate shape, and the side surface along the oblique side portion of the isosceles trapezoid and the thickness direction is a rake face. In the first insert mounting seat, The pin mirror cutter according to claim 1, wherein the cutting blade is attached so that an axial rake angle of the cutting edge is a positive angle. The insert body has a substantially rectangular flat plate shape, and the first insert mounting seat is mounted so that the axial rake angle of the cutting edge is a negative angle, and the second insert mounting seat. The pin mirror cutter according to claim 1, wherein the cutting blade is mounted so that a radial rake angle of the cutting edge is a negative angle up to -8 °.

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