JP2009095918A - Throw-away cutting tool - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a throw-away cutting tool in which a throw-away chip with a sloped or curved blade-tip ridge line is stably and rigidly secured to a tool body to prevent the life of a cutting blade from being shortened. <P>SOLUTION: In this throw-away cutting tool, the surface of the throw-away chip 1 opposed to a flat seating surface 5 in contact with a chip seat 20 is formed as a cutting face 2, at least a part of the blade-tip ridge line of the cutting blade formed at the peripheral edge of the cutting face 2 is formed in a tilted blade-tip ridge line tilted or curved relative to the seating surface 5, and the side surfaces extending from the tilted blade-tip ridge line to the seating surface 5 are formed in surfaces to be arrested 6, 7 when the side surfaces are brought into contact with arresting wall surfaces 22, 23 upwardly extending from the bottom surface 21 of the chip seat. The ridge lines 22a, 23a at the upper ends of the arresting wall surfaces 22, 23 extend generally parallel to the tilt blade-tip ridge line. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a throw-away cutting tool for detachably mounting a throw-away tip.

Generally, in a throw-away cutting tool, when a throw-away tip is fixed to a tip seat composed of a notch step provided in the tool body, the seating surface and the side surface of the throw-away tip are the bottom surface of the tip seat and the bottom surface. The method of abutting and fixing to the wall surface rising upward from the center is adopted. By the way, in the throw-away tip used in this type of throw-away type cutting tool, it is formed on the peripheral portion of the rake face formed on the surface facing the seating surface of the throw-away tip, mainly for improving the cutting performance. Some of the edge edges of the cutting edges are inclined or curved with respect to the seating surface so that the distance (height) from the seating surface changes. (For example, refer to Patent Document 1).
JP 2001-269810 A

  In the conventional throw-away cutting tool, the ridge line at the upper end in the rising direction of the wall surface of the tip seat extends substantially parallel to the bottom surface of the tip seat, and is the lowest of the inclined or curved cutting edge ridge line of the throw-away tip. It is formed at a lower position than the position. Therefore, the wall surface of the tip seat supports the side surface of the throw-away tip at a position extremely low with respect to the highest position of the edge of the cutting edge. Therefore, the clamping force for fixing the throw-away tip and the cutting resistance during cutting When receiving, there was a risk that the support and restraint could not be stably and firmly. Furthermore, since the area of the wall surface of the chip seat cannot be secured sufficiently, there is a risk that elastic deformation or plastic deformation may occur due to the clamping force or cutting resistance. In such a situation, chipping or chipping of the cutting edge occurs, so that the cutting edge life may be greatly reduced.

  The present invention has been made to solve the above-mentioned problem, and is a throw-away type that stably and firmly fixes a throw-away tip having an inclined or curved cutting edge ridge line to a tool body to prevent a reduction in the cutting edge life. An object is to provide a cutting tool.

In order to solve the above problems, the present invention has the following configuration.
The invention according to claim 1 is a throw-away type cutting tool in which a throw-away tip having a substantially polygonal plate shape is detachably fixed by a fixing means to a tip seat formed of a notch step portion provided in a tool body. The surface of the throw-away tip that faces the flat seating surface that abuts the tip seat is a rake face, and at least a part of the edge of the cutting edge formed on the periphery of the rake face is the seat. An inclined cutting edge ridge line that is inclined or curved with respect to the surface, and a side surface extending from the inclined cutting edge ridge line to the seating surface is a constrained surface when coming into contact with a constraining wall surface that rises upward from the bottom surface of the tip seat; A throwaway cutting tool characterized in that a ridge line at an upper end portion located on the inclined cutting edge ridge line side extends in a direction substantially parallel to the inclined cutting edge ridge line.

  According to the first aspect of the present invention, since the ridge line of the upper end portion in the rising direction of the constraining wall surface of the tip seat is formed to extend in a direction substantially parallel to the inclined cutting edge ridge line, the constraining wall surface is slow. The side surface of the away tip is supported and restrained at a position close to the inclined cutting edge ridge line, and a sufficient area of the region that contacts the side surface of the throw-away tip is ensured. Therefore, it is possible to prevent the movement of the throw-away tip due to the clamping force or cutting resistance, and the elastic deformation and plastic deformation of the constraining wall surface. Therefore, the throw-away tip can be stably and firmly fixed to the tip seat, and a long cutting edge life can be obtained without chipping or chipping of the cutting edge.

The invention according to claim 2 is formed in such a manner that the entire inclined cutting edge ridge line gradually approaches the seating surface as it goes from one end portion to the other end portion thereof, and is constrained formed on a side surface continuous to the inclined cutting edge ridge line. 2. The throwaway cutting tool according to claim 1, wherein a ridge line of an upper end portion of the constraining wall surface of the tip seat that is in contact with a surface extends in a direction substantially parallel to the inclined cutting edge ridge line.
In this way, when the inclined cutting edge ridge line is inclined only toward the seating surface from one end to the other end, the difference in height between the highest and lowest positions of the inclined cutting edge ridge line is particularly large. In a conventional cutting tool that supports and restrains at a position lower than the lowest position of the ridgeline, the throw-away tip attached to the tip seat becomes easy to move. However, according to the invention according to claim 2, the height difference of the inclined cutting edge ridgeline is increased. Regardless of the fact that the side surface of the throwaway tip can be supported and restrained at a position close to the inclined edge of the inclined blade edge, and the area of the area contacting the side surface of the throwaway tip can be secured sufficiently, the throwaway tip can be used as the tip seat. It can be stably and firmly fixed. In addition, the difference in height between the highest and lowest sloped edge edges is particularly large, so the increase in cutting resistance when biting on the work material is mitigated, and chip evacuation is improved, resulting in improved machinability. In addition to the improvement, the effect of extending the cutting edge life is further enhanced because the increase in wear of the cutting edge or the chipping of the cutting edge is suppressed.

According to a third aspect of the present invention, there is provided a mounting hole penetrating the rake face and the seating surface of the throw-away tip, and a clamp screw inserted through the mounting hole is provided on the bottom surface of the tip seat to be fastened to the screw hole. The throwaway tip is configured to be fixed to the tip seat by pressing the bottom surface and the restrained surface thereof against the bottom surface and the restraining wall surface of the tip seat, respectively. 2. A throw-away cutting tool according to 2.
According to the third aspect, since the throw-away tip is fixed to the tip seat using the clamp screw, the throw-away tip is attached to the bottom surface of the tip seat and the number of parts is simple and the structure is simple. Since sufficient pressing force can be obtained on the constraining wall surfaces, the degree of freedom in designing the throw-away tip and the tool body can be increased. Moreover, when it is set as the aspect which presses the inner wall surface of the attachment hole of a throw away tip with a clamp screw, a throw away tip is pressed very strongly against the restraint wall surface of a chip seat, The structure of Claim 1 or 2 By having it, the movement which lifts from the bottom face of a chip seat by the force pressed by the restraint wall surface of a chip seat is suppressed, and it fixes stably and firmly.

The invention according to claim 4 is characterized in that the highest position of the ridgeline at the upper end of the constraining wall surface of the tip seat is higher than the position where the clamp screw and the inner wall surface of the mounting hole of the throw-away tip abut. It is a throw away type cutting tool given in any 1 paragraph of Claims 1-3.
According to the fourth aspect of the present invention, since the highest position of the ridgeline at the upper end of the constraining wall surface of the tip seat is higher than the position where the clamp screw and the inner wall surface of the attachment hole of the throw-away tip are in contact, The away tip is prevented from being lifted from the bottom surface of the tip seat, and is fixed stably and firmly.

The invention according to claim 5 is characterized in that the lowest position of the ridgeline of the upper end portion of the constraining wall surface of the tip seat is higher than the position where the clamp screw and the inner wall surface of the mounting hole of the throw-away tip abut. It is a throw away type cutting tool given in any 1 paragraph of Claims 1-3.
According to the fifth aspect of the present invention, since the lowest level of the ridgeline at the upper end of the restraint wall surface of the tip seat is higher than the position where the inner wall surface of the mounting hole is pressed by the clamp screw, The effect of preventing floating from the bottom surface of the chip seat becomes extremely high. Therefore, the throw-away tip can be stably and firmly fixed to the tip seat when performing high-feed cutting or heavy cutting by increasing the force generated by the clamp screw to press the throw-away tip against the tip seat. It becomes.

  According to the throw-away cutting tool according to the present invention, the ridge line at the upper end in the rising direction of the constraining wall surface of the tip seat is formed so as to extend in a direction substantially parallel to the inclined cutting edge ridge line. Supports and restrains the side surface of the throw-away tip at a position close to the inclined cutting edge ridge line, and sufficiently secures the area of the region in contact with the side surface of the throw-away tip. Therefore, it is possible to prevent the movement of the throw-away tip due to the clamping force or cutting resistance, and the elastic deformation and plastic deformation of the constraining wall surface. Therefore, the throw-away tip can be stably and firmly fixed to the tip seat, and a long cutting edge life can be obtained without chipping or chipping of the cutting edge.

  A throw-away end mill as an embodiment of a throw-away cutting tool to which the present invention is applied will be described with reference to the drawings. FIG. 1 is an exploded perspective view of the present throw-away end mill. FIG. 2 is a plan view of the throw-away end mill shown in FIG. 3 is a side view of the throwaway end mill shown in FIG. 4 is an enlarged perspective view of the tip seat of the throw-away end mill shown in FIG. 5 is a cross-sectional view taken along line AA in FIG. 6 to 8 are a front view, a left side view, and a plan view of a throw-away tip attached to the throw-away end mill shown in FIG. 1, respectively.

  As shown in FIGS. 1 to 3, this throw-away end mill is configured such that a throw-away tip 1 is detachably attached to a tip outer peripheral portion of a tool body 10 having a round bar shape by a clamp screw 30. Specifically, on the outer peripheral surface of the tip portion of the tool body 10, three tip discharge grooves 11 that open to the front end surface 10b and the outer peripheral surface 10a are formed at substantially equal intervals in the circumferential direction. As shown in FIG. 4, a tip seat 20 composed of a notch step is formed at the tip of the wall surface of the tool body facing the rotation direction K, and the throw-away tip 1 is fixed to the bottom surface 21 of each tip seat. A female screw hole 25 for screwing the clamp screw 30 as a means is formed.

  As shown in FIGS. 6 to 8, the throw-away tip 1 attached to the present throw-away type end mill has a substantially polygonal plate shape, and a lower surface constituted by a flat substantially polygonal surface is a seating surface 5. The surface facing the seating surface 5 is a rake surface 2, a cutting edge is formed on the peripheral edge of the substantially polygonal surface that becomes the rake surface 2, and the side surface extending from the cutting blade to the seating surface 5 is a flank 3. Being done. The throw-away tip 1 is a throw-away tip that can be used in two corners, in which a substantially polygonal surface serving as the rake face 2 exhibits a 180 ° rotationally symmetric shape with respect to the center thereof.

  A round corner 4a having an arc shape in a plan view is formed at a pair of corners of a substantially polygonal surface serving as the rake face 2, and an outer peripheral edge 4b is formed on a long side extending from one end of the round corner 4a. An inner peripheral edge 4d is formed on each short side formed from the other end of the round corner 4a with a secondary cutting edge 4c for finishing the processed surface. As shown in FIGS. 6 and 7, the cutting edge ridge line of the round corner 4a has the highest point farthest from the seating surface 5 in the middle of the cutting edge ridge line in the direction along the ridge line. As it goes to both ends of 4a, it gradually approaches the seating surface 5 and forms an inclined cutting edge ridge line having a convex curve shape toward the upper side of the rake face 2. The cutting edge ridgeline of the outer peripheral blade 4b is an inclined cutting edge ridgeline that gradually approaches the seating surface 5 from one end contacting the round corner 4a in the direction along the ridgeline toward the other end. Further, the edge edge line of the inner peripheral edge 4d (including the edge edge line of the auxiliary cutting edge 4c) is also an inclined edge edge that gradually approaches the seating surface 5 as the distance from the round corner 4a increases.

  A side surface extending from the edge edge of the round corner 4a to the seating surface 5 is a flank 3a constituted by a conical surface or a cylindrical surface protruding outward corresponding to the edge edge line of the round corner 4a. On the other hand, the side surfaces extending from the cutting edge ridge lines of the outer peripheral blade 4b and the inner peripheral blade 4d that form a straight line to the seating surface 5 are flank surfaces 3b and 3d configured as flat surfaces. The flank surfaces 3a, 3b, and 3d of the round corner 4a, the outer peripheral blade 4b, and the inner peripheral blade 4d are positive flank surfaces that are retracted inward as approaching the seating surface 5 from the respective edge edges. Furthermore, a mounting hole 8 through which a clamp screw 30 serving as a fixing means for fixing the throw-away tip is inserted is formed through the seating surface 5 at the center of the rake face 2. The throw-away tip 1 is made of a hard material such as cemented carbide, coated cemented carbide, cermet or ceramics.

  When the throwaway tip 1 is seated on the bottom surface 21 of the tip seat and the rake face 2 is placed in the rotational direction K, the throw-away tip 1 and the outer peripheral blade 4b facing the wall surface of the tip seat 20 and the inner circumference The flank surfaces 3b and 3d (side surfaces) connected to the blade 4d abut against the restraining wall surfaces 22 and 23 of the tip seat as restrained surfaces 6 and 7, and a clamp screw 30 inserted through the mounting hole 8 is attached to the bottom surface 21 of the tip seat. For providing, it is fixed to the chip seat 20 so as to be detachable by being fastened to the screw hole 25. Each constraining wall surface 22, 23 of the chip seat is configured as a flat surface so as to be able to come into surface contact with the constrained surfaces 6, 7 of the throw-away tip 1, or the ridge lines 22a, 23a of the upper end portion of the constraining wall surface are The constrained surfaces 6 and 7 are configured as flat surfaces whose rising inclination angle is slightly steeper than the constrained surfaces 6 and 7 so as to be in line contact with the constrained surfaces 6 and 7. In addition, as shown in FIG. 4, the wall surface of the chip seat facing the flank 3a connected to the round corner 4a is formed with a thinned portion 24 that is slightly recessed so that a gap is formed between the flank 3a. Has been.

  Further, as shown in FIG. 5, the shaft center of the female screw hole 25 is slightly closer to the restraint wall surfaces 22 and 23 side of the tip seat than the shaft center of the attachment hole 8 of the throw-away tip (center shift amount B: 0 in FIG. 5). .About 0.5 to 0.50 mm), the seat surface 31a having the inverted truncated cone shape of the head portion 31 of the clamp screw 30 screwed into the female screw hole 25 has the restraint wall surface 22 and restraint of the tip seat. The inner wall surface 8a of the attachment hole of the throw-away tip located in the direction approaching both of the surfaces 23 (in the direction of the line AA in FIG. 2) is strongly pressed, and the throw-away tip 1 is placed on the bottom surface of the tip seat. 21 and the restraining wall surfaces 22 and 23 are pressed firmly and fixed to the chip seat 20. Further, a presser foot 40 that is propelled from the rake face 2 side of the throw-away tip 1 toward the seating surface 6 side by a countersunk screw is provided as a fixing means, and the rake face 2 of the throw-away tip 1 is seated by the presser foot 40. You may press toward 5 side. When the presser foot 40 is added, the throw-away tip 1 is more firmly fixed to the tip seat 20.

  As shown in FIG. 4, the ridge lines 22a and 23a at the upper end of the tip seat are connected to the restraint wall surfaces 22 and 23 of the tip seat and the restrained surfaces 6 and 7 of the throw-away tip. It is formed substantially parallel along the inclined cutting edge ridge line at the upper ends of the restrained surfaces 6 and 7 to be in contact with each other. By adopting such a characteristic configuration, the area of the constraining wall surfaces 22 and 23 is sufficiently secured and rigidity is increased, and the force per unit area received by the constraining wall surfaces 22 and 23 is reduced and thrown. Elastic deformation and plastic deformation caused by force when fixing the away tip 1 and cutting resistance during cutting are suppressed. In addition, since the restraint wall surfaces 22 and 23 of the tip seat support and restrain in a position close to the inclined edge of the throwaway tip, it is stable even when receiving a clamping force for fixing the throwaway tip or a cutting resistance during cutting. And can be supported and restrained firmly. Therefore, chipping and chipping of the cutting edge are prevented, and a longer cutting edge life can be obtained.

  As shown in FIG. 6, the entire inclined edge of the outer peripheral edge 4b of the throw-away tip 1 gradually approaches only the seating surface 5 side from one end connected to the round corner 4a toward the other end. The side surface that is formed and extends from the inclined cutting edge ridge line to the seating surface 5 is the constrained surface 6, while the ridge line 22 a at the upper end of the constraining wall surface of the tip seat that contacts the constrained surface 6 is along the inclined cutting edge ridge line. It is desirable that they are formed substantially in parallel.

  In this way, when the inclined cutting edge ridge line is inclined from one end to the other end only to the seating surface side, and the height difference between the highest and lowest positions of the inclined cutting edge ridge line is particularly large, the inclined cutting edge ridge line Since the increase in cutting resistance when biting into the work material is moderated or chips are discharged in a certain direction, the machinability is greatly improved. In addition, the ridgeline 22a at the upper end of the constraining wall surface of the chip seat is formed substantially parallel along the inclined cutting edge ridgeline, thereby ensuring a sufficient area of the constraining wall surface 22 and increasing rigidity and suppressing elastic deformation. Since the restraining wall surface 22 of the tip seat is supported and restrained at a position close to the inclined edge of the throwaway tip, the clamping force for fixing the throwaway tip and the cutting resistance at the time of cutting are received. In this case, the effect of supporting and restraining stably and strongly becomes remarkable.

  Like the present throwaway tip 1, a clamp screw 30 inserted through the mounting hole 8 is fastened to the screw hole 25 in order to provide the bottom surface 21 of the tip seat, so that the throwaway tip 1 has its seating surface 5 and When adopting a mode in which the restrained surfaces 6 and 7 are pressed against the bottom surface 21 and the restraining wall surfaces 22 and 23 of the chip seat and fixed to the chip seat 20, the number of parts is larger than when a presser foot or a wedge member is employed. Even though the structure is small and the structure is simple, sufficient force can be obtained to press the throw-away tip 1 against the bottom surface 21 and the constraining wall surfaces 22 and 23 of the tip seat, so that the design of the throw-away tip 1 and the tool body 10 can be achieved. And the throw-away tip 1 can be firmly fixed to the tip seat 20.

  In the conventional cutting tool, the ridge lines 22a and 23a of the upper end portion of the constraining wall surface of the tip seat are formed so as to extend in parallel with the bottom surface of the tip seat at a position lower than the lowest position of the inclined edge ridge line of the throw-away tip. The Therefore, when the fixing means that the seat surface 31a of the head of the clamp screw presses the inner wall surface 8a of the attachment hole of the throw-away tip is adopted, the ridgelines 22a and 23a become lower than the pressing position. The throw-away tip behaves like being lifted from the bottom surface 21 of the tip seat. On the other hand, in the present embodiment, since the highest position of the ridge lines 22a and 23a is higher than the pressing position C, the throw-away tip 1 does not exhibit a behavior of lifting from the bottom surface 21 of the tip seat and is stable. And firmly fixed to the chip seat 20.

  In this embodiment, the lowest position of the ridgelines 22a and 23a at the upper end of the restraint wall surface of the tip seat is higher than the position C where the seat surface 31a of the head of the clamp screw presses the inner wall surface 8a of the attachment hole of the throw-away tip. If it is provided, the effect of preventing the throw-away tip 1 from lifting up from the bottom surface 21 of the tip seat becomes extremely high, which is preferable. In particular, when the tip 1 is fixed to a cutting tool used for high-efficiency cutting such as high feed cutting or heavy cutting, the throw-away tip 1 is stably fixed without lifting from the bottom surface 21 of the tip seat, which is extremely excellent. Cutting edge life is obtained.

  The throw-away tip attached to the cutting tool is composed of an inclined cutting edge ridge line in which the outer peripheral edge 4b and the auxiliary cutting edge 4c are inclined in one direction (only toward the seating surface) from one end to the other end. It is not limited to a thing, You may be comprised by the inclination cutting edge ridgeline which has the bending part or bending part from which an inclination direction changes. FIG. 9 is a schematic view of the tip seat 20 of the cutting tool to which the throw away tip 1 constituted by the inclined edge of the outer peripheral blade 4b having a bent portion is mounted. From the direction in which the tip seat 20 faces the restraint wall surface 22. FIG. Although it is desirable that the ridge line 22a at the upper end of the constraining wall surface be faithfully formed in parallel along the inclined cutting edge ridge line of the throw-away tip 1 indicated by a two-dot chain line, it may be difficult in processing. In such a case, as illustrated in FIGS. 9A and 9B, the ridge line 22a may be formed by an approximate curve of parallel lines faithful to the inclined cutting edge ridge line. Further, as shown by the two-dot chain line in FIG. 9C, the height difference between the both ends of the inclined cutting edge ridge line of the outer peripheral blade 4b is very large, and the inclined cutting edge ridge line forms a wave shape having a plurality of bent portions. In this case, as illustrated in the figure, the ridge line 22a at the upper end of the constraining wall surface of the chip seat may be formed in a straight line parallel to a straight line connecting both ends of the inclined blade edge ridge line.

It is a disassembled perspective view of the throwaway type end mill to which the present invention is applied. FIG. 2 is a plan view of the throw-away end mill shown in FIG. 1. It is a front end side view of the throw-away end mill shown in FIG. FIG. 2 is an enlarged perspective view of a tip seat of the throw-away end mill shown in FIG. 1. It is the sectional view on the AA line in FIG. FIG. 2 is a front view of a throw-away tip attached to the throw-away end mill shown in FIG. 1. FIG. 2 is a left side view of a throw-away tip attached to the throw-away end mill shown in FIG. 1. FIG. 2 is a plan view of a throw-away tip attached to the throw-away end mill shown in FIG. 1. It is a mimetic diagram of a tip seat of a cutting tool with which a throw away tip constituted by an inclined blade edge ridge line in which an outer peripheral blade has a bent portion is mounted.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Throw away tip 2 Rake face 3 Flank 4a Round corner 4b Outer peripheral blade 4d Inner peripheral blade 5 Seating surface 6, 7 Constrained surface 8 Mounting hole 8a Inner wall surface of the mounting hole 10 Tool body 20 Tip seat 21 Bottom surface of the tip seat 22 , 23 Chip seat restraint wall surface 22a, 23a Ridge line 30 at upper end of restraint wall surface Clamp screw 31 Clamp screw head portion 31a Clamp screw head seat surface

Claims (5)

A throw-away type cutting tool in which a throw-away tip having a substantially polygonal plate shape is detachably fixed by a fixing means to a tip seat made of a notch step provided in the tool body,
The surface facing the flat seating surface that contacts the tip seat of the throw-away tip is a rake surface,
At least part of the cutting edge ridge line of the cutting edge formed on the peripheral portion of the rake face is an inclined cutting edge ridge line that is inclined or curved with respect to the seating surface,
The side surface extending from the inclined cutting edge ridge line to the seating surface is a restrained surface when coming into contact with the restraining wall surface rising upward from the bottom surface of the tip seat,
A throw-away cutting tool, wherein a ridge line at an upper end portion located on the inclined cutting edge ridge line side of the constraining wall surface extends in a direction substantially parallel to the inclined cutting edge ridge line. The inclined blade edge ridge line is formed so as to gradually approach the seating surface as it goes from one end to the other end,
The ridge line of the upper end portion of the constraining wall surface of the tip seat that is in contact with the constrained surface formed on the side surface that is continuous with the inclined cutting edge ridge line extends in a direction substantially parallel to the inclined cutting edge ridge line. The throw-away type cutting tool according to 1. A mounting hole penetrating the rake face and the seating face of the throw-away tip is formed,
The throw-away tip is pressed against the bottom surface and the constraining wall surface of the tip seat by pressing the bottom surface and the constrained surface of the tip seat by tightening the clamp screw inserted into the mounting hole on the bottom surface of the chip seat. The throw-away cutting tool according to claim 1 or 2, wherein the throw-away cutting tool is fixed to the tip seat. The highest position of the ridge line of the upper end portion of the constraining wall surface of the tip seat is higher than the position where the clamp screw and the inner wall surface of the attachment hole of the throw-away tip are in contact with each other. The throw-away type cutting tool according to any one of claims. The lowest position of the ridgeline of the upper end part of the constraining wall surface of the tip seat is higher than the position where the clamp screw and the inner wall surface of the attachment hole of the throw-away tip are in contact with each other. The throw-away type cutting tool according to any one of claims.

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