JPH0524224U - Throwaway type rolling tool - Google Patents

Abstract

(57) [Summary] [Structure] The first tip 3A mounted on the tip of the tool in the cutting blade row 14 where the rotation locus formed on the tool body 1 is continuous, and the rotation locus on the first tip 3A. The second tip 3B which is continuous with the second tip 3B and the other cutting edge row 14 adjacent to this cutting edge row 14 have a narrow angle θ1 that sandwiches the tool axis O in the axial direction view. The other first tip 3A attached to the tip of the tool body sets the tool axis O larger than a narrow angle θ2 sandwiching the tool axis O when viewed in the axial direction. Further, on the surface 7 facing the front side in the tool rotation direction T of the first tip 3A, the negative rake surface 11 is sequentially turned inward in the radial direction of the tool body 1.
a, 12a and positive rake faces 11b, 12b are formed,
Further, this surface 7 is formed in a multi-step surface shape by a plurality of constituent surfaces 11 and 12 that intersect so as to draw the convex ridge line L. [Effect] It is possible to improve the tool rigidity at the tool tip portion where an excessive load acts during cutting work.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention is a milling cutter in which a plurality of throw-away chips (hereinafter referred to as chips) are mounted on the outer peripheral surface of a tool body that rotates around an axis, and a continuous cutting edge row is formed in the rotation locus. It relates to throw-away type rolling tools such as end mills and end mills.

[0002]

[Prior Art]

 As such a throw-away type rolling tool, for example, the throw-away type end mills described in Japanese Utility Model Publication No. 58-196019 and Japanese Utility Model Publication No. 60-22215 are known. In these end mills, a tip pocket is formed on the outer peripheral surface of a cylindrical tool body, which is recessed inward in the radial direction of the tool body from the tip of the tool body toward the base end side. A tip mounting seat is formed on the surface facing the front side in the direction, and the tip is mounted on the tip mounting seat with its cutting edge (main cutting edge) protruding from the outer peripheral surface. Here, the tip pocket may be formed continuously along the axial direction of the tool body, or may be formed in a spiral shape intermittently on the outer peripheral surface of the tool body. In each case, the tips are arranged so as to be displaced in at least one of the circumferential direction and the axial direction of the tool body. A cutting blade row is formed.

On the other hand, the tip mounted on the tip mounting seat is formed in a flat plate shape such as a square shape or a circular shape, and at least one of the two end surfaces orthogonal to the thickness direction is scooped. The cutting edge is formed on the ridge or edge of this rake face. Further, in the above end mill, with such a chip with its rake face facing forward in the tool rotation direction, the clamp screw inserted in the thickness direction of the chip is screwed to the chip mounting seat. It is fastened and fixed to the tool body and used for cutting work. As a chip fixing means in such a rolling tool, as shown in, for example, Japanese Utility Model Laid-Open No. 60-143608, a storage recess is formed on the outer peripheral surface of the tool body, and the storage recess is provided with a chip. It is also known that it is attached and wedged with wedges.

[0004]

[Problems to be solved by the device]

 By the way, among such cutting blades forming the above-mentioned cutting blade row in such a throw-away type rolling tool, the cutting blade arranged at the tip of the tool body is usually the first work piece in the cutting blade row. Since it is a part that bites on the surface to be cut, it is inevitable that the load that acts during cutting will be excessive compared to the cutting edge that is arranged on the base end side of the tool body. This tendency is particularly noticeable when cutting with a large depth of cut, or when cutting hard materials, etc., and the tip of the tool body that holds the insert tends to lack rigidity. was there.

[0005]

[Means for Solving the Problems]

 The present invention has been made to solve such a problem, and a slow-away type rolling tool according to claim 1 is provided with a plurality of tools on the outer peripheral surface of the tool body from the tip of the tool body toward the base end side. In the throw-away type rolling tool, in which the inserts are arranged so as to be offset from each other in at least one of the circumferential direction and the axial direction of the tool body, and a row of cutting edges having continuous rotation trajectories is formed, There is a first tip that is mounted on the tip of the tool body and a second tip that is in the same cutting edge row as the first tip and has a continuous rotation trajectory on the first tip. The narrow angle that sandwiches the axis of the tool in the direction of the axis lies between the second tip and the row of cutting edges adjacent to the second row of cutting edges on which the first and second tips are arranged in the circumferential direction of the tool body. The other first tip that is attached to the tip of the tool body. Bets are characterized in the this set larger than the narrow angle sandwiched axial line direction view of the above axis.

A throw-away type cutting tool according to a second aspect is the throw-away type cutting tool according to the first aspect, in which at least one of the tips arranged on the outer peripheral surface of the tool body is attached to the tip of the tool body. On the surface of the insert that is connected to the main cutting edge that forms the cutting edge row and faces the front side in the tool rotation direction, from the side that is connected to the main cutting edge to the inside in the radial direction of the tool body. The present invention is characterized in that a negative rake surface extending in a direction orthogonal to the surface facing the outer peripheral side of the main body and a positive rake surface inclined to the regular cutting edge with respect to the main cutting edge are formed. Further, in the throw-away type rolling tool according to claim 3, among the chips arranged on the outer peripheral surface of the tool body, at least a first chip mounted on the tip of the tool body forms the cutting edge row. It is characterized in that the surface that is continuous with the cutting edge and faces the front side in the tool rotation direction is formed into a multi-step surface by a plurality of constituent surfaces that intersect each other so as to draw a convex edge line where the intersecting ridge lines reach the main cutting edge. To do.

[0007]

[Action]

 In the throw-away type rolling tool having such a configuration, the first tip mounted on the tip of the tool body of the chips forming the above-mentioned cutting edge row and the same cutting edge row as this first tip are provided. And a second tip that is continuous with the first tip in a rotation trajectory, and another first tip of the cutting edge row that is circumferentially adjacent to the cutting edge rows of these first and second tips. Between the first chip and the second chip, the narrow angle between these chips is the narrow angle between the first chip and the second chip, and the narrow angle between the first chip and the second chip is the second chip and the other first chip. It is set larger than the narrow angle between and. Therefore, the distance between the first tip and the other first tips in the tool rotation direction is also the distance from the first tip to the second tip is the second tip to the other first tip. Will be larger than the interval. Therefore, as described above, a sufficient thickness is secured in the circumferential direction of the tool body on the rear side of the tool tip in the tool rotation direction where an excessive load acts during cutting, and the tool tip The rigidity can be improved.

Further, a negative rake face and a positive rake face are sequentially formed inward in the radial direction of the tool main body on a face of the first tip facing the tool rotation direction front side, so that the entire face is positive. While the cutting edge strength is improved as compared to the case of using a rake face, it is possible to reduce the cutting resistance compared to the case of using a negative rake face as a whole. Furthermore, by forming the surface facing the front side in the tool rotation direction into a multi-step surface by a plurality of constituent surfaces that intersect so as to draw a convex ridge line, the main cutting edge of the first insert can be cut from the tool tip side. As the axial rake angle changes toward the base end side beyond the convex edge line, the cutting resistance can be reduced without impairing the edge strength of the main cutting edge.

[0009]

【Example】

 1 to 4 show a front milling cutter which is an embodiment of the present invention. In these figures, the tool main body 1 is a substantially disc-shaped member integrally formed from steel or the like, and the center line of the disc is the tool axis O, and the disc-shaped mounting portion is on the base end side in the tool axis O direction. 1A is formed, and the outer peripheral surface on the tip side from the mounting portion 1A is a tapered surface that once expands in diameter toward the tip side and then contracts. Further, a mounting hole 1B for mounting the front milling cutter on the spindle end of a machine tool or the like is provided through the center of the tool body 1 coaxially with the tool axis O. A key groove 1C is formed along the diametrical direction of the tool body 1 on the base end face of the mounting portion 1A from the peripheral edge of the base end side opening. In this embodiment, a plurality of tip mounting seats 2 ... Are formed on the tapered surface 1D on the tip side of the tool body 1 and the tip 3 is attached to each of these tip mounting seats 2. It is fixed by a clamp screw 4.

5 to 8 show the chip 3 mounted on the chip mounting seat 2 in this embodiment. This chip 3 is formed by molding cemented carbide or the like into a substantially rhombic flat plate shape, and intersects both end surfaces 5 and 6 parallel to each other orthogonal to the thickness direction of the flat plate and four peripheral surfaces 7 ... In the ridge portion, a total of four sub flanks 8 ... Are alternately formed on the one end face 5 side and the other end face 6 side in the circumferential direction. On the other hand, a main cutting edge 9 is formed at the intersection ridge line between the end surfaces 5, 6 and the peripheral surface 7 on the side opposite to the side on which the sub flanks 8 are formed. Also, in the circumferential direction of the chip 3, the one end face 5 side and the other end face 6 side are alternately arranged. Further, an intersecting ridgeline of a sub flank 8 extending in a direction intersecting with the main cutting edge 9 on the side of the acute angle end C1 of the rhombus formed by the both end surfaces 5, 6 and a peripheral surface 7 continuous with the main cutting edge 9. A sub cutting edge 10 is formed in the portion so as to be continuous with one end of the main cutting edge 9 on the acute angle end C1 side.

Here, each of the peripheral surfaces 7 is formed in a multi-step surface shape which is bent by one step in the direction along the main cutting edge 9 by the two constituent surfaces 11, 12 that intersect each other at an obtuse angle. Then, one end of the intersecting ridge line L of each of the constituent surfaces 11 and 12 is made to reach the main cutting edge 9 connected to the peripheral surface 7, whereby the main cutting edge 9 reaches the acute angle end C1 of the tip 3. It is divided into a continuous first main cutting edge 9a and a second main cutting edge 9b continuous with the obtuse-angled end C2 of the tip 3, and is generally bent in a single step and protrudes in a substantially "U" shape. It is formed into a mold. Further, on each of the constituent surfaces 11 and 12 of the peripheral surface 7, the negative rake surfaces 11a and 12a and the positive rake surface 11b are sequentially arranged from the side continuous with the main cutting edge 9 toward the opposite side in the thickness direction of the tip 3. 12b are formed. Of these rake faces, the negative rake faces 11a and 12a are both formed in a direction orthogonal to the both end faces 5 and 6 of the chip 6, and their widths W1 in the thickness direction are mutually They are set equal and constant along the main cutting edge 9. The width W1 of the negative rake faces 11a, 12a is set so as not to exceed the width W2 of the sub cutting edge 10 in the chip thickness direction as shown in FIG. 7, that is, W1> W2. ing.

On the other hand, the positive rake surfaces 11b and 12b are inclined surfaces with respect to the main cutting edge 9 in a regular angle side, that is, as the tip thickness direction is separated from the side continuous with the negative rake surfaces 11a and 12a. It is a tapered surface that faces inward of the chip 3. In this embodiment, as shown in FIG. 8, the main cutting edge of the positive rake face 11b of the constituent face 11 of the constituent faces 11 and 12 constituting the peripheral face 7 arranged on the side of the acute angle end C1. 9 so that the inclination angle φ1 with respect to 9 is larger than the inclination angle φ2 with respect to the main cutting edge 9 of the positive rake face 12b of the constituent surface 12 disposed on the side of the obtuse angle end C2, that is, φ1> φ2. It is set. Further, the sub flank 8 is a flat surface formed by cutting the ridges of intersections of the positive rake faces 11b and 12b and the end faces 5 and 6 at 45 ° with respect to the end faces 5 and 6. The edge 3 of the tip 3 is connected to the auxiliary cutting edge 10 on the side of the acute angle C1 and is separated from the side of the acute angle C1 with the intersecting ridge line L of each of the constituent surfaces 11 and 12 forming the peripheral surface 7. The width is gradually reduced toward the obtuse angle C2 side beyond the intersection, and the width is set to 0 at the obtuse angle C2. Reference numeral 13 in the drawing is a through hole through which the clamp screw 4 for fixing the chip 3 to the chip mounting seat 2 is inserted.

On the other hand, the tip mounting seats 2 on which the tips 3 are mounted are formed so as to be recessed inward in the radial direction of the tool body 1 substantially perpendicular to the tapered surface 1 D of the tool body 1. It is composed of a mounting seat bottom surface 2a and two mounting seat wall surfaces 2b and 2b standing upright from the mounting seat bottom surface 2a and connected to the taper surface 1D. The other side is shaped to face the front side and the other side to the tip side of the tool. A screw hole 2c into which the clamp screw 4 is screwed is formed in the mounting seat bottom surface 2a. In the chip 3, one of the both end surfaces 5 and 6 is brought into close contact with the mounting seat bottom surface 2a, and then the two peripheral surfaces 7 and 7 sandwiching the acute angle end C1 are brought into contact with the mounting seat wall surfaces 2b and 2b. It is mounted on the mounting base 2. Further, by inserting the clamp screw 4 into the through hole 13 and screwing the clamp screw 4 into the screw hole 2c, the tip 3 of the tip 3 faces the outer side in the radial direction of the tool body 1, One peripheral surface 7 that intersects the other surface of the surfaces 5 and 6 via the main cutting edge 9 is directed to the front side in the tool rotation direction T, and the main cutting edge 9 is further projected from the tapered surface 1D. It is fixed to the tool body 1 in this state. A relief portion 2d is provided at the intersection of the two mounting wall surfaces 2b, 2b to avoid interference with the acute angle end C1 of the chip 3. Further, the screw hole 2c is slightly provided on the side of the escape portion 2d so that the two peripheral surfaces 7, 7 of the chip 3 are pressed against the mounting wall surfaces 2b, 2b when the clamp screw 4 is screwed and tightened. Is eccentric to. In this way, by mounting the tip 3 on the tip mounting seat 2 with the one circumferential surface 7 of the tip 3 having the above-described configuration facing the tool rotation direction T front side, the above-mentioned main cutting edge 9 is attached to the front milling cutter. A surface of the tip 3 that faces the outer peripheral side of the tool body 1 in order from the continuous side toward the inner side of the tool body 1, that is, a negative rake surface 11a that extends in a direction orthogonal to one of the end surfaces 5 and 6 of the tip 3. 12a and the positive rake faces 11b and 12b inclined to the main cutting edge 9 on the side of a regular angle are formed. Simultaneously with this, the surface that faces the front side in the tool rotation direction T is a multi-step surface due to the two constituent surfaces 11 and 12 that intersect each other so that the intersecting ridge lines draw the convex ridge line L that reaches the main cutting edge 9. Will be formed into a shape.

In the present embodiment, such tip mounting seats 2 are alternately formed on the tip end side and the base end side of the taper surface 1D along the circumferential direction of the tool body 1. The tip mounting seat 2A and the tip end mounting seat 2B located on the rear side in the tool rotating direction T of the tip mounting seat 2B form a pair. The pair of tip mounting seats 2A and 2B are composed of a main cutting edge 9A of the first tip 3A mounted on the tip mounting seat 2A on the tip side and a second cutting edge 2A mounted on the tip mounting seat 2B on the base end side. The main cutting edge 9B of the tip 3B is set so as to overlap and be continuous with each other in its rotation track, and the main cutting edges 9A and 9B of the first and second tips 3A and 3B make one The cutting blade row 14 is configured. Further, in this embodiment, chip pockets 15A and 15B are formed on the front side of the tool mounting direction T of these chip mounting seats 2A and 2B, respectively. These tip pockets 15A and 15B are both formed in the tapered surface 1D in a groove shape along the tool axis O direction, and are in front of the tip mounting seat 2A on which the first tip 3A is mounted. 15A is opened at the tip end surface of the tool body 1 and is closed at the base end side, and conversely, the tip end side is closed at the tip pocket 15B in front of the tip mounting seat 2B on which the second tip 3B is mounted. It is opened only on the base end side.

Further, in the present embodiment, the narrow angle at which the first tip 3A and the second tip 3B of the one cutting edge row 14 sandwich the tool axis O in the direction of the tool axis O is the second angle. The tip 3B and the other first tip 3A of the other cutting edge row 14 located on the rear side in the tool rotation direction T of the one cutting edge row 14 make the tool axis O the direction of the tool axis O It is set to be larger than the narrow angle that it is sandwiched. That is, as shown in FIG. 2, with the tip 3 mounted on each tip mounting seat 2, a plane Q including the tool axis O and passing through the forefront end of the main cutting edge 9 of the tip 3 in the tool rotation direction T Assuming, the plane Q11 passing through the tool rotation direction T foremost end of the main cutting edge 9A of the first tip 3A of the one cutting edge row 14A and the second tip 3B of this one cutting edge row 14A. The narrow angle formed by the plane Q12 passing through the foremost end of the main cutting edge 3B in the tool rotation direction T is defined as θ1, and the plane Q12 and the other cutting edge row on the rear side in the tool rotation direction T of the one cutting edge row 14 described above. If the narrow angle formed by the plane Q21 passing through the tool rotation direction T foremost end of the main cutting edge 9A of the first tip 3A in 14B and θ21 is θ2, the relationship between these narrow angles θ1 and θ2 is θ1> θ2. Is established.

In the present embodiment, a total of 6 such cutting blade rows 14 are formed, and the respective cutting blade rows 14 are arranged at equal intervals in the circumferential direction of the tool body 1. Therefore, the first inserts 3A, 3A of the two adjacent cutting blade arrays 14, 14 sandwich the tool axis O in the direction of the tool axis O, that is, the narrow angle θ1 and the narrow angle. The sum with θ2 is set to 60 °. Further, in each cutting edge row 14, the narrow angle θ1 where the first tip 3A and the second tip 3B sandwich the tool axis O is constant, and therefore, the adjacent cutting edge rows 14 and 14 respectively. The narrow angle between the second chips 3B, 3B sandwiching the tool axis O in the direction of the tool axis O is also set to 60 °. Further, the overlap amount P of the main cutting edge 9A of the first tip 3A and the main cutting edge 9B of the second tip 3B in the above-mentioned rotation locus is set to 0.1 mm to 1.0 mm in this embodiment. Has been done.

According to the face mill having such a configuration, first, as described above, the first insert 3A and the second insert 3B forming the one cutting edge row 14 make the tool axis O visible in the axial direction. The narrow angle θ1 to be sandwiched between the second tip 3B of the one cutting edge row 14 and the other tip in the other cutting edge row 14 located behind the one cutting edge row 14 in the tool rotation direction T. By setting the tip 3A and the tip 3A to be larger than the narrow angle θ2 that sandwiches the tool axis O, the distance between the first tip 3A and the second tip 3B in the tool rotation direction T in the one cutting edge row 14 is set. Can be set to be larger than the distance from the second tip 3B to the first tip 3A of the next cutting edge row 14, and accordingly, the first tip 3A can be extended to the rear side in the tool rotation direction T and the first tip 3A. Length of one tool 3 around the part that holds one insert 3A And it is possible to greatly than the length of the portion extending in the tool rotation direction T rear side of the second chip 3B. For this reason, sufficient rigidity is secured in the portion that holds the first tip 3A that may be attached to the tip of the tool body 1 and that may exert an excessive load, and this helps to prevent chattering and vibration during cutting. Therefore, it becomes possible to improve the processing accuracy of the face milling machine.

In the tip 3 having the above-described structure, one peripheral surface 7 is directed to the front side in the tool rotation direction T, and the main cutting edge 9 connected to this peripheral surface 7 is projected from the outer peripheral surface of the tool body 1. As a result, the negative rake faces 11a and 12a and the positive rake faces 11b and 12b are sequentially formed on the front milling cutter from the main cutting edge 9 inward in the radial direction of the tool body 1. It will be. With such a configuration, the angle of the tip of the cutting edge is set to be larger than that in the case where the entire surface is a positive rake surface, so that the strength of the cutting edge can be improved. On the contrary, in comparison with the case where the entire surface facing the front side in the tool rotation direction T is a negative rake surface, the radial rake angle is set to the regular side on the inside in the radial direction of the surface. It is possible to reduce the time resistance. Further, as described above, by forming one peripheral surface 7 of the tip 3 facing the front side in the tool rotation direction T into a multi-step surface shape by a plurality of constituent surfaces 11 and 12 intersecting each other so as to draw the convex ridge line L. The axial rake angle of the main cutting edge 9 of the tip 3 changes in the regular direction as it goes from the tool tip side toward the base end side over the convex ridge line L. Therefore, the cutting edge angle is large on the tool tip side of the main cutting edge 9 to ensure high cutting edge strength, while the axial rake angle is on the square side on the tool base end side to reduce cutting resistance. Is possible.

As described above, according to the face milling cutter having the above-described configuration, by mounting the tip 3 having the above-described configuration, it is possible to reduce the resistance that acts on the cutting edge during cutting and maintain a high cutting edge strength. This makes it possible to prevent damage to the cutting edge and perform smooth cutting work. In particular, the narrow tip angle θ1 is set larger than the narrow tip angle θ2 by improving the cutting edge strength of the first tip 3A mounted on the tip of the tool body 1 in the cutting edge row 14 as well. Combined with the effect of, the rigidity at the tip of the tool as a whole can be further improved. Therefore, even when the above-mentioned excessive load acts, it is possible to sufficiently cope with this, and it is possible to provide a tool that can perform smooth cutting, especially when the depth of cut is large. ..

Further, in the face milling cutter of the present embodiment, as described above, the chip pockets 15A and 15B are individually provided in front of the tool rotating direction T of the first and second chips 3A and 3B forming the cutting edge row 14. Of these chip pockets 15A, 15B, the tip pocket 15A formed on the tip side of the tool body 1 is closed at the base end side, and conversely the tip pocket formed on the base end side of the tool body 1 is formed. The front end of the pocket 15B is closed. Therefore, it is possible to avoid the formation of a chip pocket that penetrates the tapered surface 1D at the tip of the tool body 1 in the direction of the tool axis O, and while ensuring the rigidity of the tool body 1 sufficiently, it is possible to obtain smooth chips. It is possible to achieve discharge. Further, by forming the tip pockets 15A and 15B in such a manner that the tip end side and the base end side of the tool body 1 are alternately staggered and one side thereof is closed, as shown in FIG. Of the tip mounting seat 2A at the tip of the tool to which the tip 3A of the tool is mounted, a rib-shaped portion extending in the circumferential direction of the tool main body 1 from the mounting seat wall surface 2b facing the front side in the tool rotation direction T to the rear side in the tool rotation direction T Will be formed. In addition, in the present embodiment, such a rib-like portion is formed at the tip of the tool body 1, so that even if an excessive load acts on the first tip 3A of the tool tip as described above, Therefore, the rigidity of No. 1 can be sufficiently maintained, and the effect of preventing the occurrence of chattering and vibration can be further enhanced. Furthermore, in the above-mentioned conventional end mill and the like, the tip is mounted with the thickness direction thereof facing the circumferential direction of the tool body, whereas in the present embodiment, the tip 3 has the thickness direction of the tool body. It is a so-called vertical blade type, which is mounted along the radial direction of No. 1. By adopting such a configuration, it is possible to reduce the portion where the tool body 1 is cut out to form the tip mounting seat 2, and it is also possible to achieve the effect of further increasing the tool rigidity. Becomes

In the embodiment described above, the present invention is applied to the throw-away type face milling cutter. However, the present invention is not limited to this, and other throw-away type cutting tools such as end mills can be used. It can also be used for. Further, in the present embodiment, one cutting edge row 14 is composed of two chips, the first and second chips 3A and 3B, but it is of course possible to compose two or more chips. Further, the number of cutting blade rows 14 formed on the tool body 1 can be appropriately set depending on the size of the tool body, cutting conditions, and the like. Furthermore, in the present embodiment, the first tip 3A mounted on the tip side of the tool body 1 and the second tip 3B mounted on the base side are described as the same tip. 3A and 3B may be different depending on cutting conditions and the like. Further, in the present embodiment, the narrow angles θ1 and θ2 at which the tips 3A and 3B sandwich the tool axis O in the direction of the tool axis O are set to the tool rotation of the main cutting edge 9 of the tips 3A and 3B as described above. A narrow angle formed by the plane Q which includes the tool axis O and which passes through the tool rotation direction T foremost end of the main cutting edge 9 with respect to the foremost end of the direction T is used as a reference. A narrow angle may be set. For example, the positions of the clamp screw 4 and the screw hole 2c of the tip mounting seat 2 may be used as a reference instead of the foremost end of the main cutting edge 9 in the tool rotation direction T.

By the way, since the relationship of θ1> θ2 is established for the narrow angles θ1 and θ2 as described above, the ratio θ2 / θ1 between the narrow angle θ2 and the narrow angle θ1 is 0 <θ2 / θ1 < It will be set within the range of 1. However, when the ratio θ2 / θ1 becomes a value very close to 1, the second chip 3B is arranged at the center of the first chips 3A, 3A of the two adjacent blade arrays 14, 14. Therefore, there is a possibility that the effects of the present invention described above may not be sufficiently achieved. On the other hand, when this ratio θ2 / θ1 takes a value close to 0, in the two cutting edge rows 14 that are adjacent to each other, the second tip 3B of one cutting edge row 14 has the other cutting edge row 14 As a result, the first chip 3A is mounted in close proximity to the first chip 3A, and the size of the chip pocket to be formed between these chips is limited. As described above, if the narrow angle ratio θ2 / θ1 becomes extremely close to 0 or 1, there will be a case. Therefore, this ratio θ2 / θ1 will depend on the size of the tool and the cutting conditions. For a milling cutter or the like provided with a cutting blade row of approximately 1.2D with respect to the tool diameter D (inch), it is desirable to set the range to 0.6 to 0.8. Also, the ratio θ2 / θ1 should be suppressed to a maximum of about 0.9 even in milling cutters used for special purposes.

[0023]

[Effect of the device]

 As described above, according to the present invention, a cutting blade row having a continuous rotation locus is formed on the outer peripheral surface of the tool body from the distal end of the tool body toward the base end side. The first tip mounted on the tip of the main body and the second tip that is in the same cutting edge row as the first tip and has a continuous locus of rotation on the first tip are along the axis of the tool body in the axial direction. A narrow angle sandwiched between the second tip and the cutting edge row adjacent to the cutting edge row where the first and second chips are arranged is attached to the tip of the tool body. Since the other first insert is set to be larger than the narrow angle that sandwiches the axis in the direction of the axis, the tool rotation direction of the first insert at the tool tip where excessive load acts during cutting work. It is possible to secure a sufficient thickness on the rear side, It can be improved that rigidity.

Further, a negative rake face and a positive rake face are sequentially formed inward in the radial direction of the tool body on the surface of the first tip facing the tool rotation direction front side, and further in the tool rotation direction front side. By forming the surface that faces the side in a multi-step surface shape by multiple constituent surfaces that intersect so as to draw a convex ridge line, the edge strength at the tool tip is ensured and the base side in the tool axial direction and the radial direction Both the axial and radial rake angles of the cutting edge change toward the conformal side as they go inward. Therefore, it is possible to maintain the cutting edge strength of the main cutting edge while reducing the cutting resistance, and in combination with the effect of improving the tool rigidity described above, it is possible to effectively suppress the occurrence of chatter and vibration of the tool. It is possible to obtain an excellent finished surface by smooth cutting.

[Brief description of drawings]

FIG. 1 is a vertical cross-sectional view of a front milling cutter according to an embodiment of the present invention.

FIG. 2 is a plan view of the embodiment shown in FIG. 1 from the front end surface side.

3 is a view of the embodiment shown in FIG. 1 as viewed from the direction A. FIG.

FIG. 4 is a view of the embodiment shown in FIG. 1 as viewed in the B direction.

5 is a perspective view of the chip 3 mounted in the embodiment shown in FIG. 1. FIG.

6 is a plan view from one end surface 5 side of the chip 3 shown in FIG.

7 is a side view of the chip 3 shown in FIG. 6 as viewed in the C direction.

8 is a DD cross-sectional view of the chip 3 shown in FIG.

[Explanation of symbols]

1 Tool body 1D Tapered surface 2 Tip mounting seat 3 Tip 3A First tip 3B Second tip 4 Clamp screw 5,6 Tip surface of tip 3 7 Circumferential surface of tip 3 8 Sub flank 9 Main cutting edge 10 Sub cutting edge 11a, 12a Negative rake surface 11b, 12b Positive rake surface 14 Cutting edge row 15A, 15B Chip pocket O Tool axis T Tool rotation direction Q Tool rotation direction Q of tool cutting axis 9 of tool 3 The first chip 3A and the second chip 3B of the cutting edge row 14 of one angle θ1 sandwiches the tool axis O in the axial direction view. And another first tip 3A of another one of the cutting edge rows adjacent to this cutting edge row, the convex ridge line of the narrow-angle L tip 3 that sandwiches the tool axis O in the axial direction view.

Claims (3)

[Scope of utility model registration request] 1. A plurality of throw-away tips are arranged on the outer peripheral surface of the tool body from the distal end to the base end side of the tool body so as to be offset from each other in at least one of the circumferential direction and the axial direction of the tool body. In a throw-away type rolling tool formed by forming a cutting blade row having continuous rotation trajectories, a first throw-away tip mounted on the tip of the tool body in the cutting blade row and the first throw-away tip. A narrow angle that the second throw-away tip, which is in the same cutting edge row as the away tip and whose rotation locus is continuous to the first throw-away tip, sandwiches the axis line of the tool body in the axial direction view, Of the throw-away tip and the first and second throw-away tips are provided at the tip of the tool body in a row of cutting blades adjacent to the tool body in the circumferential direction of the tool body. Another indexable milling tool and the first indexable insert is characterized in that it is set larger than the narrow angle sandwiched axial line direction viewed the axis being. 2. Among the throw-away tips arranged on the outer peripheral surface of the tool body, at least a first throw-away tip mounted on the tip of the tool body is connected to a main cutting edge forming the cutting edge row. Negative extending in a direction orthogonal to the surface of the throw-away tip facing the outer peripheral side of the tool body, in order from the side continuous with the main cutting edge toward the inner side in the radial direction of the tool main body on the surface facing the tool rotation direction front side. The throw-away type rolling tool according to claim 1, wherein a rake face and a positive rake face that is inclined to the main cutting edge in a regular angle side are formed. 3. A tool connected to a main cutting edge forming the cutting edge row of at least a first throw-away tip mounted on the tip of the tool body among the throw-away tips arranged on the outer peripheral surface of the tool body. The surface facing the front side in the rotation direction is formed in a multi-step surface shape by a plurality of constituent surfaces that intersect each other so as to draw a convex ridge line where the intersecting ridge lines reach the main cutting edge. The throw-away type cutting tool according to claim 2.