JP2008254127A - Cutting insert - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a cutting insert having a plurality of protrusions and recesses on a cutting edge, capable of efficient working without reducing the number of usable cutting edges. <P>SOLUTION: The cutting edge 2 having a plurality of protrusions 6 and recesses 7 between them is formed on at least one pair of opposite ridges on the front and rear faces of an insert body 1 exhibiting a planar form, as viewed from directions opposite to the obverse and reverse. In addition, a positive flank 4 gradually retreating from the cutting edge 2 as coming farther away from the obverse and reverse toward the center of the thickness direction of the insert body 1 is formed on a side face of the insert body 1 located between the pair of opposite ridges. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a cutting insert that includes a plurality of convex portions and concave portions on a cutting blade and can perform particularly efficient machining.

Thus, as a cutting insert provided with a plurality of convex portions and concave portions on the cutting blade, for example, the one described in Patent Document 1 is known. That is, in the cutting insert described in Patent Document 1, a convex portion and a concave portion are formed on two side surfaces of the insert main body that are opposite to each other, and the upper and lower surfaces of the insert main body are formed on the intersection ridge line portion. A cutting blade having a lower surface as a rake face is formed. Therefore, in this cutting insert, four cutting edges can be used in one insert body.
US Pat. No. 6,632,051

  However, in the cutting insert described in Patent Document 1, the tip surface of the convex portion serving as the flank of the cutting blade extends in a direction perpendicular to the upper and lower surfaces of the insert body, that is, a negative insert that does not have a clearance angle. Therefore, in order to avoid interference between the tip surface and the workpiece, the rake angle must be set to the negative angle side, the cutting edge becomes dull and the cutting resistance increases, This is inappropriate for efficient cutting such as increasing the feed.

  On the other hand, positive inserts with a flank inclined to the cutting edge to give a clearance angle in advance are also known, but only one of the upper and lower faces is used as a rake face for one cutting edge. That is, there is a problem that the number of cutting blades that can be used in one insert body is halved.

  The present invention has been made under such a background, and in such a cutting insert having a plurality of convex portions and concave portions on the cutting blade, it is efficient without reducing the number of usable cutting blades. It aims at providing the cutting insert which can be processed.

  In order to solve the above-described problems and achieve such an object, the present invention provides a structure in which at least a pair of opposing side ridges on the front and back surfaces of the insert body having a flat plate shape are viewed from the direction facing the front and back surfaces. A cutting blade having a plurality of convex portions and a concave portion therebetween is formed, and on the side surface of the insert body located between the pair of opposing side ridge portions, the insert is spaced apart from the front and back surfaces. A positive flank is formed which gradually recedes with respect to the cutting edge as it goes toward the center in the thickness direction of the main body.

  Therefore, according to such an insert, a cutting edge having a rake face on each of the front and back sides is formed on at least a pair of opposite side ridges on the front and back sides of the insert body, and thus can be formed on one insert body. The number of cutting edges is not reduced. The flank formed on the side surface between the front and back surfaces is a positive flank surface that is spaced apart from the front and back surfaces and gradually retreats with respect to the cutting edge toward the center of the insert body in the thickness direction. So, even if you do not set the rake angle of the front and back surfaces to be the rake face to the negative angle side, you can ensure a sufficient clearance angle in the part connected to the side cutting edge of the flank face, As a result, the cutting edge can be sharply sharpened to reduce the cutting resistance.

  Here, since the convex portion is formed in a trapezoidal shape when viewed from the direction facing the front and back surfaces, the width of the convex portion in the direction along the side ridge portion can be increased. The cutting edge strength can be improved. In particular, when the cutting insert is used for turning, when the insert body is cut into the workpiece in the direction in which the convex portion protrudes, and then cut in the direction along the side ridge, Since the feed width can be reduced, more efficient processing can be promoted.

  On the other hand, if the convex portion is formed in a triangular shape as viewed from the direction facing the front and back surfaces, it is possible to avoid an impact load from acting when the convex portion bites the workpiece from the tip. It is possible to prevent the convex part of the cutting edge from being damaged due to such an impact load, and it is possible to promote smooth cutting by smoothing the cutting and further reducing the cutting resistance. Become.

  As described above, according to the present invention, it is economical without reducing the number of cutting blades formed in the insert main body, and the cutting resistance is reduced by improving the sharpness of the cutting blades. It is possible to perform efficient cutting.

  1 to 5 show a first embodiment of the present invention. In the present embodiment, the insert body 1 is formed in a substantially rectangular flat plate shape by a hard material such as cemented carbide and is located at the center in the thickness direction (vertical direction in FIGS. 3 and 4). A pair of side ridges that are symmetrical with respect to the plane P perpendicular to the direction and are opposed to the above thickness direction on both the front and back surfaces of the substantially rectangular shape (side ridges positioned up and down in FIG. 3) Are formed with cutting edges 2, and rake faces 3 are formed at the edges of the front and back surfaces respectively connected to the cutting edges 2, and flank faces are formed on the side surfaces of the insert body 1 positioned between the cutting edges 2. 4 is formed.

  In this embodiment, the cutting edge 2 is formed on each of two side ridges (side ridges positioned up and down in FIG. 2) located on opposite sides of the square formed by the front and back surfaces, that is, 1 Two insert blades 2 are formed on one insert body 1. In addition, an attachment hole 5 for attaching the cutting insert to a holder or the like of an insert detachable cutting tool is formed in the center of the front and back surfaces so as to penetrate the insert body 1 in the thickness direction. 1 has a symmetrical shape with respect to the plane Q parallel to the side ridge portion and the vertical plane R including the center line of the mounting hole 5.

  The cutting blade 2 has a plurality of (three in this embodiment) convex portions 6 projecting in the plane R direction as shown in FIG. 2 in a plan view from the direction facing the front and back surfaces. The portions are formed at equal intervals in the direction in which the portions extend, and the portions between these convex portions 6 are the concave portions 7 (two in this embodiment). Here, in the present embodiment, the convex portion 6 is formed in an isosceles trapezoidal shape having the same shape and the same size and gradually narrowing toward the tip in the plan view, while the concave portion 7 is conversely formed. The convex portions 6 are formed in isosceles trapezoidal shapes having the same shape and size that gradually increase in width toward the projecting end side, and the isosceles trapezoids formed by the concave and convex portions 6 and 7 are also substantially the same shape and size. Has been. The corners and corners of the concave and convex portions 6 and 7 are formed in a concave and convex arc shape, and the radius of the convex arc at the corner of the convex portion 6 is smaller than the concave arc at the corner of the concave portion 7.

  As shown in FIG. 5, the rake face 3 connected to the cutting edge 2 having the uneven portions 6 and 7 has the thickness at a certain inclination angle from the protruding end of the convex portion 6 toward the inside in the plane R direction. After being inclined so as to gradually recede in the direction, it is formed so as to be cut off on the inner side of the recess 7, and the front and back surfaces of the insert body 1 on the inner side thereof are the above except for the opening of the mounting hole 5. The flat surface is perpendicular to the thickness direction. In addition, the oblique sides on the both sides of the isosceles trapezoid formed by the convex portions 6 at both ends of the plurality of convex portions 6 are extended to the inner side beyond the boundary between the rake face 3 and the flat portions of the front and back surfaces. Yes.

  And the flank 4 formed on the side surface of the insert main body 1 between the cutting blades 2 formed on the pair of side ridges is separated from the front and back surfaces toward the central portion in the thickness direction. These positive flank surfaces gradually retreat with respect to the front and back cutting edges 2. In particular, in the present embodiment, these positive flank surfaces intersect on the plane P, and in a cross section along the plane R, FIG. As shown in FIG. 4, the concave V-shape is exhibited.

  Here, as shown in FIG. 2, these positive relief surfaces are formed not only by the portion that continues to the protruding end of the convex portion 6 retreats gradually, but also by the portion that continues to the bottom of the concave portion 7 and these concave and convex portions 6 and 7. The part connected to the hypotenuse of the isosceles trapezoid is also formed so as to gradually recede toward the central part in the thickness direction.Therefore, this positive flank has a cross section perpendicular to the thickness direction from the front and back surfaces. The isosceles trapezoid that continues to the convex portion 6 gradually decreases in size toward the plane P side, while the isosceles trapezoid that continues to the recess 7 gradually increases.

  For example, when such a cutting insert is used for the outer periphery turning of the workpiece W rotating around the axis O as shown in FIG. 5, the side ridge portion on which one cutting edge 2 is formed is parallel to the axis O. The rake face 3 of the cutting edge 2 is opposed to the rotation direction T of the workpiece W, and the flank 4 connected to the cutting edge 2 is opposed to the outer peripheral face of the workpiece W to hold the insert body 1. The insert body 1 is advanced in the range up to the bottom of the recess 7 of the cutting blade 2 to cut the cutting blade 2. Next, when the cutting edge 2 is cut into the workpiece W by a predetermined cut in this way, the insert body 1 is sent to either the left or right by the width of one recess 7 in the direction of the axis O, thereby the recess 7 The outer peripheral surface of the workpiece W can be turned with a width equal to the width of 1 and the width of the cutting edge 2.

  At this time, according to the cutting insert having the above-described configuration, the flank 4 connected to the cutting edge 2 has a positive flank gradually retreating from the front and back surfaces on which the rake face 3 is formed toward the center in the thickness direction. Therefore, as shown in FIG. 5, the rake angle can be secured without setting the rake angle to the negative angle side, and therefore the rake angle can be set to 0 ° or the positive angle side. The sharpness of the cutting blade 2 can be enhanced. In addition, in the present embodiment, since the rake face 3 is inclined backward as described above, the rake angle can be set larger on the positive angle side.

  Therefore, the cutting resistance can be reduced by this, so that the cutting insert is held to cut the shaft portion sandwiched between the webs, for example, when the outer periphery of the shaft portion of the crankshaft of the engine is cut. Even if the holder protrusion length must be increased and the holding rigidity of the cutting insert is impaired and unstable, it is possible to perform high-feed cutting without causing vibration in the holder. Is. Further, in this embodiment, the flank 4 portion connected to the oblique side of the convex portion 6 is also a positive flank that gradually recedes toward the central portion in the thickness direction with respect to the oblique side. Even when cutting is performed by feeding in the direction of the axis O, cutting resistance can be reduced.

  On the other hand, the cutting edge 2 formed on the side ridge on the opposite side to the cutting edge 2 used for cutting in this way and the positive flank face thereof have a V-shaped cross section as described above. Therefore, even if the rake angle of the cutting edge 2 used for cutting is set to the positive angle side, it does not interfere with the workpiece, and is formed on a pair of opposite side ridges on the front and back surfaces. Both cutting edges 2 can be used by inverting the insert body 1. Therefore, the number of cutting edges 2 that can be formed in the insert body 1 is prevented from being reduced, and an economical cutting insert can be provided.

  Moreover, in this embodiment, since the convex part 6 of the cutting blade 2 is formed in trapezoid shape seeing from the direction facing the said front and back, the protrusion can be formed as a side with a certain amount of width. As described above, after cutting the convex portion 6 of the cutting blade 2 into the workpiece W, the machining allowance is reduced when the outer peripheral cutting is performed by feeding in the direction of the axis O, and the width of this feeding is reduced. Therefore, more efficient processing can be promoted. Moreover, the intensity | strength improvement can also be aimed at by setting it as the convex part 6 trapezoid shape in this way.

  However, instead of forming the convex portion 6 in the trapezoidal shape as described above, as in the second embodiment of the present invention shown in FIGS. You may make it form the convex part 11 which makes | forms. In the second embodiment, the same reference numerals are assigned to portions common to the first embodiment to simplify the description.

  That is, in this 2nd Embodiment, as shown in FIG. 7 in the planar view seen from the direction which opposes the said front and back, the recessed part 7 goes to the protrusion side of the convex part 11 similarly to 1st Embodiment. Are formed in the shape of isosceles trapezoids having the same shape and the same size, and the convex portion 11 has an isosceles triangle shape in which the hypotenuses of these isosceles trapezoids intersect each other as they are, In the present embodiment, a substantially equilateral triangular shape is presented. However, the protruding end is formed in a convex arc shape having a smaller radius than the concave arc at the corner of the concave portion 7 in the same manner as the corner portion of the convex portion 6 of the first embodiment. Further, the flank 4 of the cutting edge 2 that is a positive flank is inclined so as to gradually recede toward the central part in the thickness direction with respect to the hypotenuse of the isosceles triangle at the portion connected to the convex portion 11. ing.

  Therefore, in the cutting insert of the second embodiment as well, as in the first embodiment, the cutting blades 2 can be formed on the front and back sides, respectively, and it is economical, and the rake angle is set to be correct. Even if set to the corner side, interference between the flank 4 and the workpiece can be prevented, and efficient cutting with less resistance can be performed.

  Further, in the present embodiment, since the convex portion 11 has a triangular shape in the plan view, when the cutting edge 2 bites the workpiece from the convex portion 11, the cutting width gradually increases after the tip bites at one point. It becomes a form which spreads, the impact load at the time of this biting can be suppressed, and the cutting into a work can be made smooth. For this reason, even when the holding of the cutting insert tends to become unstable as described above, smooth cutting can be performed more reliably, and the load at the time of biting can be suppressed in this way, thereby the convex portion 11. It is possible to prevent the occurrence of a defect even if the shape is triangular.

1 is a perspective view showing a first embodiment of the present invention. It is the top view seen from the direction which opposes the front and back of embodiment shown in FIG. It is the front view seen from the direction which opposes the side surface in which the flank 4 of embodiment shown in FIG. 1 is formed. It is the side view seen from the direction which opposes the side surface in which the flank 4 of embodiment shown in FIG. 1 is not formed. FIG. 3 is a cross-sectional view (cross-section along a plane R in FIG. 2) of the embodiment shown in FIG. It is a perspective view which shows the 2nd Embodiment of this invention. It is the top view seen from the direction which opposes the front and back of embodiment shown in FIG. It is the front view seen from the direction which opposes the side surface in which the flank 4 of embodiment shown in FIG. 6 is formed. It is the side view seen from the direction which opposes the side surface in which the flank 4 of embodiment shown in FIG. 6 is not formed.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Insert main body 2 Cutting edge 3 Rake face 4 Relief face 5 Mounting hole 6,11 Convex part 7 Concave P The plane located in the center part of the thickness direction of the insert main body 1

Claims (3)

  A cutting blade having a plurality of convex portions and concave portions therebetween is formed on at least a pair of opposing side ridge portions on the front and rear surfaces of the insert body having a flat plate shape when viewed from the direction facing the front and rear surfaces, and On the side surface of the insert main body located between a pair of opposite side ridges, a positive relief that gradually moves away from the front and back surfaces and gradually retreats with respect to the cutting blade as it goes toward the center in the thickness direction of the insert main body. A cutting insert characterized in that a surface is formed.   The cutting insert according to claim 1, wherein the convex portion is formed in a trapezoidal shape when viewed from a direction facing the front and back surfaces.   The cutting insert according to claim 1, wherein the convex portion is formed in a triangular shape when viewed from a direction facing the front and back surfaces.

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