JP4941082B2 - Throw-away cutting tool and cutting edge tip attached to the cutting tool - Google Patents

Description

  The present invention relates to a throw-away cutting tool and a cutting edge tip attached to the throw-away cutting tool, and more particularly to a throw-away cutting tool having a small outer diameter of 16 mm or less and a cutting edge tip attached thereto.

Conventionally, in this type of throw-away cutting tool, there are ones in which two throw-away tips of the same shape and the same size are mounted to form a front blade and an outer peripheral blade. In this cutting tool, there are provided two concave grooves that are substantially opposed to the rotation axis of the tool body and are cut out in a substantially sectoral cross section. A chip mounting seat is formed on the surface facing the rotational direction of one of the concave grooves, and a chip mounting seat is also formed on the surface facing the rotational direction of the other concave groove. These tip mounting seats are mounted with throw-away tips of the same shape and size, and the main tip mounted on one tip mounting seat has the second long blade as the front blade and the first short blade as the outer peripheral blade. The sub-tips arranged in the horizontal direction and mounted on the other chip mounting seat are arranged in the vertical direction so that the first short blade is a front blade and the first long blade is an outer peripheral blade ( For example, see Patent Document 1). And this throw-away cutting tool enables both drilling and end milling by arranging two throw-away tips with the second long blade as the front blade and the first long blade as the outer peripheral blade. To do.
JP 2001-121341 A (refer to FIGS. 1 to 3)

  Since the throw-away cutting tool described in Patent Document 1 has a front blade and an outer peripheral blade, it is rotated in the horizontal direction so as to rotate around a rotation axis and to circulate the rotation axis on a circular or polygonal track. By moving in the direction perpendicular to the rotation axis and moving toward the front end side in the rotation axis direction, it is possible to perform cutting (digging) of a round hole or a square hole in the work material. Alternatively, it is possible to perform cutting processing (digging processing) of an oval groove on a work material by simply moving it linearly in the lateral direction and moving it toward the distal end side of the rotation axis. The cutting process described above is referred to as “three-dimensional machining” here.

When the throw-away cutting tool is moved laterally, the cutting force component force in the direction perpendicular to the axis of the tool body increases, causing problems such as chatter, peripheral blade breakage, and possibly tool body breakage. Since there is a fear, it is difficult to increase the feed amount (high efficiency). In particular, with a small diameter tool with a peripheral blade diameter of less than 16 mm, it is very difficult to improve the machining efficiency because the rigidity of the throw-away cutting tool cannot be secured due to the small diameter of the tool body and the small size of the throw-away tip. It was.

  Further, in the above-described three-dimensional machining, the clearance is not large between the front and outer peripheral blades of the throw-away cutting tool and the processed round hole, square hole, groove bottom surface and inner wall surface. May occur, and the work material may adhere to the front and outer peripheral blades and the flank surfaces. In this regard, the throw-away cutting tool described in Patent Document 1 removes each tip from the tool body and interchanges the positions of the throw-away tip with each other when corner-changing two tips having the same shape. Therefore, the above-mentioned adherents interfere with the tool body and each throw-away tip cannot be attached to the correct position of the tool body, and the tightening screw that fixes each throw-away tip is loosened during cutting. There was a risk that sticking would occur and the front blade and outer peripheral blade could be damaged. This problem becomes a particularly serious problem when three-dimensionally processing a material that tends to adhere to the cutting edge, such as an aluminum alloy or stainless steel.

  The present invention has been made to solve the above-described problem, and provides a throw-away cutting tool capable of improving the machining efficiency by increasing the feed amount in the lateral direction (direction perpendicular to the rotation axis). The purpose is to do.

  In order to solve the above-mentioned problem, in the invention according to claim 1, two cutting edge tips having a substantially polygonal plate shape are opposed to a tip seat provided at a tip portion of a tool body rotated around a tool axis. A throw-away type cutting tool that is detachably mounted by a fastening screw that engages with a mounting hole that penetrates the polygonal surface, and at least one of the opposing polygonal surfaces is a rake facing the tool rotation direction. A pair of peripheral edges extending from the corners protruding to the outer peripheral side of the tip of the tool body having a polygonal surface, which is a rake face, are first peripheral blades extending toward the center side and the tip side of the tool body And a second outer peripheral blade extending toward the rear end side of the tool, respectively, from an end portion of the first outer peripheral blade located near the center of the tool body toward the center side and the rear end side of the tool body. The front edge is on the peripheral edge And the first outer peripheral blade, the second outer peripheral blade, and the front blade are arranged so that the rotation trajectories around the tool axis overlap each other, and at least one of the front blades reaches or approaches the tool axis It is a throw-away type cutting tool characterized by extending to a position.

According to the first aspect of the invention, particularly when the cutting edge tip is downsized, the mounting hole, the first outer peripheral edge, and the front edge can be prevented from approaching. In the efficiency machining, chipping, breakage, and the like due to damage to the first outer peripheral blade and the front blade are prevented.

  According to the present invention, it is possible to improve the machining efficiency by increasing the feed amount in the lateral direction (direction orthogonal to the rotation axis).

  Hereinafter, a throw-away cutting tool to which the present invention is applied will be described with reference to the drawings. 1 and 2 are perspective views of the tip of the present throw-away type cutting tool. FIG. 3 is a front view of the present throw-away cutting tool. 4 to 8 are enlarged views of the tip portion of the present throw-away cutting tool, FIG. 4 is an enlarged front view, FIG. 5 is an enlarged rear view, and FIG. 6 is an enlarged side view of the tip view. 7 is an enlarged bottom view, and FIG. 8 is an enlarged plan view. FIG. 9 and FIG. 10 are diagrams for explaining the center side cutting edge tip and the outer peripheral side cutting edge tip mounted on the present throw-away type cutting tool, respectively. FIG. 11 is a diagram showing the situation of three-dimensional machining with the present throw-away type cutting tool, (a) showing the situation of three-dimensional machining of a round hole, and (b) of three-dimensional machining of an oval groove. Indicates the situation.

  As shown in FIGS. 1, 2, and 3 to 8, the tool body 10 of the present throw-away type cutting tool is made of a steel material such as an alloy steel, has a substantially round bar shape, and has a tool axis CL at the tip. A pair of first chip pockets 11A are formed on the opposite sides of the tool body 10 with the outer peripheral surface of the tool body 10 cut away. A pair of tip seats 12A and 12B that cut out the wall surface is formed at the tip of the wall surface of the first chip pocket 11A facing the tool rotation direction K, and a cutting edge tip 20 is formed on the bottom surface 12a of each tip seat. A female screw hole into which a tightening screw 40 for fixing 30 is screwed is provided. A second chip pocket 11B is formed on the rear end side of the pair of first chip pockets 11A. The second chip pocket 11B is connected to the first chip pocket 11A. These 2nd chip pockets 11B are formed so that the outer peripheral surface of the tool main body 10 may be notched spirally toward the rear end side.

  The two cutting edge tips 20 and 30 mounted on the tool body are made of hard materials such as cemented carbide, cermet, ceramics, etc., and have different polygonal plate shapes as shown in FIG. 9 and FIG. Mounting holes 28 and 38 penetrating through the polygonal surface, rake surfaces 21 and 31 are formed on at least one polygonal surface, and a seating surface for seating on the bottom surface 12a of the chip seat is formed on the other polygonal surface. 26a and 36a are formed, and constrained surfaces constrained by the chip seats 12A and 12B are formed on at least one side surface. In the present embodiment, constrained surfaces 27b, 27c, 37b, and 37c are formed on two side surfaces, respectively. Corner blades 22 and 32 are formed at one corner of the polygonal surface that forms the rake surfaces 21 and 31, and first peripheral blades 23A and 33A are formed at a pair of peripheral edges extending from the corner blades 22 and 32, respectively. And second outer peripheral blades 23B, 33B are formed, and front end blades 24, 34 adjacent to the first outer peripheral blades 23A, 33A are provided at the opposite ends of the corners of the first outer peripheral blades 23A, 33A. Each is formed. When viewed from the direction perpendicular to the rake faces 21, 31, the intersecting portions of the first outer peripheral blades 23A, 33A and the second outer peripheral blades 23B, 33B and the intersecting portions of the first outer peripheral blades 23B, 33B and the front blades 24, 34 are both obtuse angles. It is formed to make.

  As shown in FIGS. 4 and 5, the two cutting edge tips 20, 30 correspond to the corresponding chip seats 12 </ b> A, 12 </ b> B by using fastening screws 40 that engage with mounting holes 28, 38 that penetrate the upper and lower surfaces thereof. It is detachably attached to. The two cutting edge tips 20 and 30 have rake faces 21 and 31 facing the tool rotation direction K, corner blades 22 and 23 project toward the outer peripheral side of the tip of the tool body 10, and first outer peripheral edges 23A and 33A are the corners. The second outer peripheral blades 23B and 33B extend from the corner blades 22 and 32 toward the rear end side of the tool from the blades 22 and 23 toward the center side and the front end side of the tool body 10, and further, the front surface The blades 24 and 34 are disposed so as to extend from the end portions of the first outer peripheral blades 23A and 33A located near the center of the tool body 10 toward the center side and the rear end side of the tool body 10. As can be seen from FIGS. 1 and 2, the first outer peripheral flank 23a, 33A, the second outer peripheral knives 23B, 33B and the side surfaces extending from the front knives 24, 34 to the seating surfaces 26a, 36a 33a, 2nd outer periphery flank 23b, 33b, and front flank 24a, 34a are each formed. These flank surfaces are formed as positive flank surfaces that are inclined so as to retract inside the cutting edge tips 20 and 30 as they approach the seating surfaces 26a and 36a. Furthermore, the first outer peripheral blades 23A and 33A, the second outer peripheral blades 23B and 33B, and the front blades 24 and 34 are two effective blades with overlapping rotation trajectories around the tool axis CL. The front blade of one of the two cutting blade tips is longer than the front blade of the other cutting blade tip and reaches the center of the tool body or a position close to 1 mm or less from the center. It is formed as follows. Hereinafter, the one cutting edge tip is referred to as a center side cutting edge tip 20, and the other cutting edge tip is referred to as an outer peripheral side cutting edge tip 30.

  As shown in FIGS. 4 to 6, constraining surfaces 12 b and 12 c for constraining the cutting edge tips 20 and 30 are formed on the two wall surfaces rising from the bottom surface 12 a of the tip seat, and in the tool axis CL direction. The wall surface extending from the front end portion to the rear end side of the tip seats 12A and 12B is a radial restraint surface 12b, and the wall surface extending inward from the outer peripheral portion of the tip seat 12A and 12B in the radial direction of the tool body 10 is the axial restraint surface 12c. It is said. In each of the cutting edge tips 20 and 30, radially constrained surfaces 26 b and 36 b constrained by the radially constraining surface 12 b are formed on the side surfaces facing the second outer peripheral flank surfaces 23 a and 33 a, and the front flank 24 a is formed. , 34a are formed with axially restrained surfaces 26c, 36c restrained by the axial restraining surface 12c. These constrained surfaces are exclusively constrained by the constraining surfaces 12b and 12c formed on the wall surface rising from the bottom surface 12a of the tip seat of the tool body, with no cutting edges formed at the ridges intersecting the rake surfaces 21 and 31. It is a flat surface that intersects the seating surfaces 26a, 36a at a substantially right angle.

  As can be seen from FIGS. 9 and 10, the center-side cutting edge tip 20 has a first outer peripheral edge 23 </ b> A, a second outer peripheral edge 23 </ b> B, and a first outer peripheral edge 23 </ b> A in a plan view as viewed from the direction orthogonal to the rake surfaces 21 and 31. And the front edge 24 intersect each other at an obtuse angle, the radial direction constrained surface 26b and the axial direction constrained surface 26c intersect substantially at right angles, and the front edge 24 and the axial direction constrained surface 26c are parallel to each other. The radially constrained surface 26b, the radially constrained surface 26b, and the axially constrained surface 26c are formed so as to intersect at substantially right angles. In the outer peripheral cutting edge tip 30, the first outer peripheral blade 33A and the second outer peripheral blade 33B, the first outer peripheral blade 33A and the front blade 34 intersect each other at an obtuse angle, and the front blade 34 and the axially restricted surface 36c are parallel. Yes, the front blade 34 and the radially constrained surface 36b form an obtuse angle, and the radially constrained surface 36b and the axially constrained surface 36c form an acute angle.

  4 and 5, linear or curved finishing blades 23Ba and 33Ba extending in a direction substantially parallel to the tool axis CL are formed in a portion adjacent to the corner blades 22 and 32 of the second outer peripheral blades 23B and 33B. In addition, linear or curved relief portions 23Bb and 33Bb that gradually approach the center side of the tool body 10 as it goes to the rear end side are formed in the portions that are continuous with the rear end side of the finishing blades 23Ba and 33Ba. . It should be noted that the second outer peripheral blades 23B and 33B may be configured entirely by the finishing blades 23Ba and 33Bb, or all of them may be configured by the relief portions 23Bb and 33Bb.

  The throw-away cutting tool having the above configuration is rotated around the tool axis CL, and is sent to the tip side along the direction of the tool axis CL, whereby the first outer peripheral blades 23A, 33A and the front blade 24, The first outer peripheral blades 23A and 33A alone or the first outer peripheral blades 23A and 33A and the second outer peripheral blades 23B can be drilled by 34 and moved in the lateral direction (direction orthogonal to the tool axis CL). , 33B can be used for end milling such as side milling and grooving, as well as three-dimensional machining using front blades 24, 34 and at least one of first outer peripheral blades 23A, 33A and second outer peripheral blades 23B, 33B. Thus, cutting of round holes, square holes, oval grooves, and the like can be performed. For example, in the three-dimensional machining of a round hole, as shown in FIG. 11 (a), the throw-away cutting tool is rotated around the tool axis CL, and the tool axis CL is circulated on a circular path. The three-dimensional machining of the oval groove is performed by moving the throw-away type cutting tool in the tool axis CL as shown in FIG. 11B. The rotation is performed by rotating the tool axis CL in the horizontal direction along the longitudinal direction of the groove and moving the tool axis CL toward the tip side in the tool axis CL direction. By performing such three-dimensional machining, it is possible to cut a round hole and a square hole having a diameter larger than the tool diameter of the throw-away type cutting tool, and an oval groove having a width substantially the same as the tool diameter. Become.

  In the present throw-away type cutting tool, the first outer peripheral blades 23A, 33A extend toward the center side and the distal end side of the tool body 10, so that the component force of the cutting force acting in the lateral direction is applied to the outer peripheral blade. Since the cutting thickness of the first outer peripheral blades 23A and 33A is smaller than that of the conventional tool and the load on the first outer peripheral blades 23A and 33A is reduced. When cutting by moving in the lateral direction, problems such as chattering, chipping of the first outer peripheral blades 23A and 33A, and breakage of the tool body 10 can be prevented. And since the thickness of the chip | tip produced | generated from the 1st outer periphery blades 23A and 33A is also smaller than a conventional tool, the damage added to a cutting blade when it bites in a chip | tip becomes small. From the above, the amount of feed in the lateral direction is increased compared to the conventional cutting tool, and the machining efficiency can be improved.

  Furthermore, the intersection (corner blades 22 and 32) of the first outer peripheral blades 23A and 33A and the second outer peripheral blades 23B and 33B positioned on the outermost peripheral side of the cutting tool, and the first peripheral blade positioned on the foremost side of the cutting tool. The intersections of the outer peripheral blades 23A, 33A and the front blades 24, 34 are both obtuse when viewed from the direction perpendicular to the rake faces 21, 31, and the cutting blade strength is increased. As a result, the feed amount in the horizontal direction can be further increased, and the feed amount during drilling can be increased, so that the machining efficiency can be further improved, and damage such as cutting edge defects at each intersection can be suppressed. As a result, the blade life is improved.

  The angle κ formed by the rotation trajectory of the first outer peripheral blades 23A and 33A around the tool axis CL and the plane perpendicular to the tool axis CL is preferably set in the range of 5 to 30 ° (FIGS. 4 and 5). reference). By doing so, the cutting resistance when fed in the lateral direction is mainly received in the direction of the tool axis CL where high rigidity is obtained in the tool body 10, so that the feed amount is increased and the occurrence of chatter at that time is suppressed. The The first outer peripheral blades 23A and 33A may have not only a linear shape but also an arc shape or a curved shape that is convex toward the tip side of the tool body 10. In that case, an angle κ formed by a straight line connecting both ends of the arc and the curve and a plane perpendicular to the tool axis CL may be set in a range of 5 to 30 °.

  Since the first outer peripheral blades 23A, 33A and the front blades 24, 34 that function at the time of drilling are formed in a V-shape with the intersection of the two as the vertices when viewed from the direction orthogonal to the rake surfaces 21, 31, respectively. The component forces in the tool radial direction of the cutting force that act on each other cancel each other. Therefore, the radial deflection of the tool body 10 is reduced, the feed amount is increased, and chattering at that time is suppressed.

  In the center side cutting edge tip 20 and the outer peripheral side cutting edge tip 30 mounted on the tool body 10, when viewed from the direction perpendicular to the rake faces 21, 31, the mounting holes 28, 38 have their centers at the tool axis. It is desirable to be provided at a position away from the first cutting edges 23A, 33A and the front cutting edges 24, 34 from the midpoint of each cutting edge tip 20, 30 in the CL direction. In this case, since the thickness from the female screw hole provided at the position facing the mounting holes 28 and 38 of the bottom surface 12a of the chip seat to the tip surface of the tool body 10 can be prevented, the tool rigidity is reduced. Is prevented, and the cutting blade tips 20 and 30 are firmly fixed to the tip seats 12A and 12B. Further, in each of the cutting edge tips 20 and 30 that are reduced in size as the diameter of the cutting tool is reduced, the attachment holes 28 and 38 can be prevented from approaching the first outer peripheral edges 23A and 33A and the front cutting edges 24 and 34. Therefore, loss, breakage, and the like when the first outer peripheral blades 23A, 33A and the front blades 24, 34 are damaged are prevented.

  As shown in FIGS. 9 and 10, in the thickness direction of the center side cutting edge tip 20 and the outer side cutting edge tip 30, the first outer peripheral edge 23A, 33A and the second outer peripheral edge 23B, 33B are at the highest corner. It is formed so as to be inclined with respect to the seating surfaces 26a and 36a so as to gradually become lower as the distance from the blades 22 and 32 increases. When the center-side cutting edge tip 20 and the outer peripheral-side cutting edge tip 30 are mounted on the tool body 10, the corner blades 22 and 32 are positioned closest to the front side in the tool rotation direction K, and the first outer peripheral cutting edges 23A and 33A. The second outer peripheral blades 23B and 33B are disposed to be inclined so as to move backward in the tool rotation direction K as they are separated from the corner blades 22 and 32 (see FIGS. 6, 7 and 8). Accordingly, the rake angle in the radial direction of the first outer peripheral blades 23A and 33A and the rake angle in the axial direction of the second outer peripheral blades 23B and 33B are set to the positive side with respect to the mounting posture of the cutting blade tips 20 and 30 to the tool body. Since it is possible to increase the thickness, it is possible to increase the feed amount when the cutting tool is moved in the lateral direction in order to achieve both the securing of the thickness on the rear side in the tool rotation direction K of the tip seats 12A and 12B and the improvement of the sharpness. Further, it is possible to prevent the first outer peripheral blades 23A and 33A and the second outer peripheral blades 23B and 33B from being broken and the tool body 10 from being damaged. Since the discharge direction of the chip | tip produced | generated from a 2nd outer periphery blade faces the rear end side, the improvement of chip | tip discharge property can be achieved.

  Furthermore, in the center side cutting edge tip 20 and the outer peripheral side cutting edge chip 30, the rake surfaces 21 and 31 extending from the first outer peripheral cutting edges 23A and 33A and the second outer peripheral cutting edges 23B and 33B are divided into two equal parts of the corner cutting edges 22 and 32. Since it is inclined so as to gradually descend toward the seating surfaces 26a and 36a as it moves away from the cutting edge in the linear direction (see FIGS. 9C and 10C), the rake angle in the radial direction is set to the positive side. Increases the sharpness of the product.

  The center-side cutting edge tip 20 and the outer peripheral-side cutting edge chip 30 are provided with radially constrained surfaces 27b and 37b and axially constrained surfaces 27c and 37c facing the second outer peripheral blades 23B and 33B and the front blades 24 and 34, respectively. The chip seats 12A and 12B are restrained by the corresponding restraining surfaces 12b and 12c. These radially restrained surfaces 27b and 37b and axially restrained surfaces 27c and 37c do not have any cutting edges at the ridge portions intersecting with the rake surfaces 21 and 31 and the seating surfaces 26a and 36a, respectively. Since the surfaces 12b and 12c are exclusively constrained, adhesion of the work material accompanying the cutting process does not occur on the constrained surface and is always fixed accurately and strongly to the tool body 10. Therefore, in high-efficiency machining with a high feed amount and cutting amount, each cutting blade tip 20 and 30 does not rattle, and stable cutting without chipping or chipping of the cutting blade is possible.

  Further, in the center side cutting edge tip 20 and the outer peripheral side cutting edge tip 30, the angle at which the radially restrained surfaces 26b, 36b and the axially restrained surfaces 26c, 36c intersect is set to 90 ° or an acute angle. Then, the cutting force is pressed against the radial restraint surface 12b and the axial restraint surface 12c of the chip seat and is firmly fixed to the chip seats 12A and 12B. Further, since the restrained surfaces 26b, 36b, 26c, and 36c are formed so as to intersect at right angles to the seating surfaces 26a and 36a, the cutting edge tips 20 and 30 are prevented from being lifted by cutting resistance. The There is no rattling of each cutting edge tip 20, 30 and stable cutting without chipping or chipping of the cutting edge is possible.

  With respect to the lengths L1 and L2 in the tool axis line CL direction of the ridge line portion combining the first outer peripheral blades 23A and 33A and the second outer peripheral blades 23B and 33B, whichever of the center side cutting edge tip 20 and the outer peripheral side cutting edge tip 30 It is desirable that the length L1 of one of the cutting blade tips is set in a range of 80% to 100% of the length L2 of the other cutting blade tip (see FIGS. 4 and 5). Then, since the number of effective blades in the range of 80% to 100% of the length L1 is 2, the burden on the first outer peripheral blades 23A and 33A and the second outer peripheral blades 23B and 33B is reduced. High-efficiency cutting with large amount and depth of cut becomes possible.

  With respect to the lengths L3 and L4 in the radial direction of the ridge line portion combining the first outer peripheral blades 23A and 33A and the front blades 24 and 34, either one of the center side cutting edge tip 20 and the outer peripheral side cutting edge tip 30 is cut. The length L4 in the blade tip is preferably set in the range of 60% to 95% of the length L3 in the other cutting tip, and particularly preferably in the range of 75% to 95% (see FIG. 4 and FIG. 5). Then, the number of effective blades in the range of 60% to 90%, particularly preferably in the range of 75% to 95% of the length L3 is 2, so that the first outer peripheral blades 23A and 33A and the front blade 24, The burden of 34 is reduced, and efficient cutting with these cutting edges becomes possible.

  In the present embodiment, even if the straight edge blades 25 and 35 extending in the direction substantially perpendicular to the tool axis CL of the tool body are provided at the intersections of the first outer peripheral blades 23A and 33A and the front blades 24 and 34. Good. When the wiping blades 25 and 35 are provided, the processed surfaces by the wiping blades 25 and 35 when moved in the lateral direction are smoothed, and excellent finished surface roughness can be obtained. It is desirable that the length of the wiping blades 25 and 35 in the extending direction is a length exceeding at least the lateral feed amount. Note that the wiping blades 25 and 35 are not limited to a linear shape, and may be formed in a convex arc shape toward the tool tip side. In this case, the chord connecting both ends of the convex arc is formed so as to be substantially orthogonal to the tool axis CL.

  Since the second outer peripheral blades 23B and 33B are formed so as to extend parallel to the tool axis CL, the inner wall surfaces of round holes or square holes cut by the second outer peripheral blades 23B and 33B are smoothed in the three-dimensional machining. Can be finished. In the present embodiment, linear or curved finishing blades 23Ba and 33Ba extending in a direction substantially parallel to the tool axis CL are formed in a part adjacent to the corner blades 22 and 32 of the second outer peripheral blades 23B and 33B. In addition, linear or curved relief portions 23Bb and 33Bb that gradually approach the center side of the tool body 10 as they go to the rear end side are formed in the portions that continue to the rear end side of the finishing blades 23Ba and 33Ba. ing. In this case, in the processing of a round hole, square hole, or oval groove by three-dimensional processing, the cutting tool moves to a position deeper than the length in the axial direction CL of the finishing blades 23Ba and 33Ba. However, since the relief portions 23Bb and 33Bb do not contact the inner wall surface of the round hole, square hole or oval groove, an increase in cutting resistance is prevented and the inner wall surface of the inner wall due to the biting of chips is prevented. Scratches and missing parts are prevented. When the cutting in the tool axis line CL direction of the second outer peripheral blades 23B, 33B exceeds the length of the finishing blades 23Ba, 33Ba in the tool axis line CL direction, the relief portions 23Bb, 33Bb are also involved in the cutting in addition to the finishing blades 23Ba, 33Ba. However, the smoothness of the inner wall surface of the processed hole or the processed groove may be slightly impaired. Therefore, when importance is attached to the smoothness of the inner wall surfaces of the machining holes and the machining grooves, it is desirable that the lengths of the finishing blades 23Ba and 33Ba in the direction of the tool axis CL are larger than the cuts of the second outer peripheral blades 23B and 33B. .

  The respective cutting edge tips 20 and 30 are positions where the respective mounting holes 28 and 38 are equal to each other with respect to the first outer peripheral blades 23A and 33A and the front cutting edges 24 and 34 when viewed from the direction perpendicular to the rake faces 21 and 31. In addition, since the cutting blade tips 20 and 30 can be formed using the same material chip, the material chips can be aggregated and economical. Has the advantage of becoming.

It is a perspective view of the front-end | tip part of the throw away type cutting tool to which this invention is applied. It is another perspective view of the front-end | tip part of the throw away type cutting tool shown in FIG. It is a front view of the throw away type cutting tool to which the present invention is applied. It is an enlarged front view of the front-end | tip part of the throw away type cutting tool shown in FIG. FIG. 4 is an enlarged rear view of the tip portion of the throw-away cutting tool shown in FIG. 3. FIG. 4 is an enlarged side view of the throwaway cutting tool shown in FIG. It is an enlarged bottom view of the front-end | tip part of the throw away type cutting tool shown in FIG. It is an enlarged plan view of the front-end | tip part of the throw away type cutting tool shown in FIG. It is a figure explaining the center side cutting edge chip | tip with which the throwaway type cutting tool shown in FIG. 1 is mounted | worn, (a) is a top view, (b) is an A1 arrow line view, (c) is B1. It is an arrow view, (d) is a C1 arrow view. It is a figure explaining the outer peripheral side cutting edge chip | tip with which the throwaway type cutting tool shown in FIG. 1 is mounted | worn, (a) is a top view, (b) is an A2 arrow line view, (c) is B2 It is an arrow view, (d) is a C2 arrow view. It is a figure which shows the state of the three-dimensional processing by the throw-away type cutting tool shown in FIG. 1, (a) shows the state of the three-dimensional processing of a round hole, (b) is the three-dimensional processing of the oval groove. Indicates the situation.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Tool main body 11 Chip pocket 12 Tip seat 12a Tip seat bottom surface 12b Tip seat radial restraint surface 12c Tip seat axial restraint surface 20 Center side cutting tip 30 Outer peripheral cutting tip 21, 31 Rake face 22, 32 Corner blades 23A, 33A First outer peripheral blades 23B, 33B Second outer peripheral blades 24, 34 Front blades 26a, 36a Seating surfaces 26b, 36b Radially constrained surfaces 26c, 36c Axial constrained surfaces 28, 38 Mounting holes 40 Tightening screw

Claims (5)

A substantially polygonal plate shape is formed, a mounting hole penetrating the opposing polygonal surface is formed, a rake surface is formed on at least one of the polygonal surfaces, and the other is formed on the bottom surface of the chip seat A constrained surface constrained by the tip seat is formed on at least one side surface, and a pair of peripheral edges extending from one corner of the polygonal surface serving as a rake face are provided with a first outer peripheral edge and a second peripheral edge. Each of the outer peripheral blades is formed, and a front blade that intersects with the first outer peripheral blade is formed at the opposite end of the corner of the first outer peripheral blade,
The angle formed by the first outer peripheral blade and the second outer peripheral blade is an obtuse angle when viewed from the direction perpendicular to the rake face,
When viewed from the direction perpendicular to the rake face, the angle formed between the first outer peripheral blade and the front blade is an obtuse angle,
In order to prevent the mounting hole from approaching the first outer peripheral blade and the front blade, the center of the mounting hole is more than the center of the cutting blade tip when viewed from the direction perpendicular to the rake face. A cutting edge tip provided at a position away from the outer peripheral edge and the front edge. A corner blade is formed at the corner,
In the thickness direction based on the seating surface, the corner blade is at the highest position compared to other cutting blades,
2. The cutting edge tip according to claim 1, wherein the first outer peripheral blade and the second outer peripheral blade are formed to be inclined so as to gradually become lower as they are separated from the corner blade. Clamping tool that engages with a mounting hole penetrating through a polygonal surface facing two cutting edge chips forming a substantially polygonal plate shape on a tip seat provided at the tip of a tool body rotated about a tool axis It is a throw-away type cutting tool that is detachably mounted by,
One corner of the rake face protrudes to the outer peripheral side of the tip of the tool body,
A first outer peripheral edge extending toward the front of the tool body is formed on the peripheral edge from the corner toward the center of the tool body,
A second outer peripheral edge is formed on the peripheral edge from the corner toward the tool body rear end side,
A front blade is formed on a peripheral edge extending from an end portion of the first outer peripheral blade located near the center of the tool main body toward the center side and the rear end side of the tool main body, and the first outer peripheral blade and the second outer peripheral blade are formed. And the rotation trajectories around the tool axis of the front blade are arranged to overlap each other,
At least one of the front blades reaches the tool axis line or extends to a close position.
In order to prevent the mounting hole from approaching the first outer peripheral blade and the front blade, the center of the mounting hole is more than the center of the cutting blade tip when the cutting blade tip is viewed from a direction perpendicular to the rake face. Is also provided at a position away from the first outer peripheral blade and the front blade . On the outer peripheral surface of the tool body, a chip pocket formed by cutting out the outer peripheral surface is formed,
The chip pocket includes a first chip pocket connected to the tip of the tool body, a second chip pocket connected to the first chip pocket and spirally formed toward the rear end of the tool body. With
Of the wall surfaces of the first chip pocket, a wall surface located on the front side in the tool body rotation direction with respect to the rake face of the cutting edge tip is curved and extends toward the outer peripheral side of the tool body,
The throwaway cutting tool according to claim 3, wherein the second chip pocket is formed in a spiral shape with a constant cross-sectional shape . The second outer peripheral blade is connected to the corner and extends parallel to the tool axis, and the relief is connected to the finishing blade and gradually approaches the tool axis as it goes to the rear end side of the tool body. indexable cutting tool according to claim 3 or 4 <br/> be characterized and a part.

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