WO2017068922A1 - Cutting insert and cutting tool - Google Patents

Abstract

A first cutting blade (5a) and a second cutting blade (5b) are connected together via a connection portion (6). The first cutting blade (5a) has a first inclined section (5a1) approaching a middle plane M as the distance thereof from a first corner portion (7a) increases. The connection portion (6) has a second inclined section (6a) separating from the middle plane M as the distance thereof from the first cutting blade (5a) increases, and a linear section (6b) linearly extending between the second inclined section (6a) and the first inclined section (5a1) as viewed from the side. The linear section (6b) has, as viewed from the side, a smaller inclination angle with respect to a second end surface (3) than an inclination angle A of the first inclined section (5a1).

Description

Cutting inserts and cutting tools

The present invention relates to a cutting insert attached to a cutting tool, and a cutting tool including the cutting insert.

The substantially polygonal plate-like cutting insert can have a plurality of cutting edges. Such a cutting insert is economical and widely used because it can be used by replacing the position with another cutting edge even if one cutting edge cannot be used. On the other hand, in order to reduce cutting resistance, cutting inserts that are arranged so that the cutting edge is inclined in a side view are often used.

As a conventional cutting insert and cutting tool, those described in Patent Document 1 are known. The cutting insert of patent document 1 is provided with the substantially triangular upper surface and lower surface, and the side surface extended between them. A cutting blade is formed at the intersecting ridge line portion between the upper surface and the side surface. The scissors cutting blade includes a main cutting blade, a sub cutting blade, an inclined cutting blade, and a corner. The main cutting blade is inclined so as to approach the lower surface as it is separated from the corner. The inclined cutting blade connects the main cutting blade and the sub cutting blade.

Special table 2012-527360 gazette

In order to make the cutting insert compact while providing two or more types of inclined cutting blades, it is desirable that the connecting portion connecting each cutting blade is small (short in length). For this reason, like the inclined cutting blade described in Patent Document 1, the connection portion may rise steeply. When an inclined cutting blade that rises sharply is used for cutting, chip discharge is hindered, and the cutting blade may be chipped or chipped.

An object of the present invention is to provide a cutting insert in which chipping and chipping hardly occur from a connecting portion even when a plurality of cutting edges are arranged so as to be inclined in a side view, and a cutting tool including the cutting insert.

The cutting insert of the present invention includes a first end surface having a first corner portion and a second corner portion, a second end surface facing away from the first end surface, a first end surface, and a first end surface. A peripheral side surface extending between the two end surfaces, and a cutting edge forming at least a part of a cross ridge line portion between the first end surface and the peripheral side surface. The cutting edge is located between the first corner portion and the second corner portion, the first cutting edge and the second cutting edge disposed on the opposite side of the first corner portion with respect to the first cutting edge. Including cutting edges. The first cutting edge and the second cutting edge are connected to each other via a connection portion. A first inclined portion that is disposed between the first end surface and the second end surface and defines the intermediate plane that intersects the peripheral side surface, and the first cutting edge approaches the intermediate plane as the distance from the first corner portion increases. Have The connecting portion includes a second inclined portion that is separated from the intermediate plane as it is separated from the first cutting edge, and a linear portion that extends linearly in a side view between the second inclined portion and the first inclined portion. And have. In the side view, the linear portion has an inclination angle with respect to the second end surface smaller than the inclination angle of the first inclined portion.

Another cutting insert according to the present invention includes a first end surface having a first corner portion and a second corner portion, a second end surface facing away from the first end surface, and a first end surface. A peripheral side surface extending between the first end surface and the second end surface, and a cutting edge forming at least a part of an intersecting ridge line portion between the first end surface and the peripheral side surface. The cutting edge is located between the first corner portion and the second corner portion, the first cutting edge and the second cutting edge disposed on the opposite side of the first corner portion with respect to the first cutting edge. Including cutting edges. The first cutting edge and the second cutting edge are connected to each other via a connection portion. A first inclined portion that is disposed between the first end surface and the second end surface and defines the intermediate plane that intersects the peripheral side surface, and the first cutting edge approaches the intermediate plane as the distance from the first corner portion increases. Have The connecting portion is curved in a substantially arc shape in a side view between the second inclined portion and the second inclined portion and the first inclined portion that are separated from the intermediate plane as they are separated from the first cutting edge. An arcuate portion extending. In a side view, the radius of curvature when the arc-shaped portion is approximated by an arc is in the range of 5 mm or more and 1000 mm or less.

The cutting tool of the present invention includes the cutting insert of the present invention.

According to the present invention, it is possible to provide a cutting insert in which chipping and chipping are unlikely to occur from a connecting portion even when a plurality of cutting edges are arranged so as to be inclined in a side view, and a cutting tool including the cutting insert.

It is a perspective view of the cutting insert concerning a 1st embodiment. It is a perspective view of the cutting tool equipped with the cutting insert of FIG. It is a top view of the cutting insert of FIG. FIG. 4 is an enlarged view of a part IV in FIG. 3. It is an enlarged view of the V section of FIG. It is a side view of the cutting insert of FIG. It is an enlarged view of the VII part of FIG. It is another side view of the cutting insert of FIG. It is a bottom view of the cutting insert of FIG. It is a perspective view of the cutting insert which concerns on 2nd Embodiment. It is a top view of the cutting insert of FIG. It is a side view of the cutting insert of FIG. It is an enlarged view of the XIII part of FIG.

Hereinafter, embodiments will be described with reference to the drawings as appropriate. First, the cutting insert 1 which concerns on 1st Embodiment is demonstrated, referring FIGS. 1-9.

The cutting insert 1 includes two end surfaces 2 and 3 and a peripheral side surface 4. The two end faces 2 and 3 face substantially opposite to each other. The peripheral side surface 4 extends between the two end surfaces 2 and 3. As shown in FIG. 3, the cutting insert 1 has a substantially triangular shape when viewed from a direction facing one end surface 2. As shown in FIG. 9, the other end surface 3 also has a substantially triangular shape when viewed from the direction facing the end surface 3. That is, the cutting insert 1 has a substantially triangular plate shape.

The shape of the cutting insert 1 is 120 ° rotationally symmetric with respect to a reference axis C passing through the two end faces 2 and 3. That is, the cutting insert 1 has a three-fold rotationally symmetric shape with respect to the reference axis C. The reference axis C passes through the center of each of the two end faces 2 and 3. The cutting insert 1 is formed with a mounting hole 9 extending so as to penetrate these two end faces 2 and 3. The central axis of the attachment hole 9 substantially coincides with the reference axis C of the cutting insert 1. The reference axis C extends so as to be orthogonal to the first end surface 2. The second end surface 3 is a substantially flat surface. The second end surface 3 functions as a seating surface when the cutting insert 1 is mounted on the cutting tool 20. The first end face 2 and the second end face 3 are arranged in parallel to each other. Therefore, the reference axis C extends so as to be orthogonal to the second end surface 3.

Here, for ease of explanation, one end surface 2 of the two end surfaces is referred to as an “upper surface”, and the other end surface 3 is referred to as a “lower surface”. However, the terms “above” and “below” are not intended to limit the present invention and are not intended to be construed in a limited manner based on these terms.

As described above, the cutting insert 1 has a substantially triangular plate shape that is 120 ° rotationally symmetric. Therefore, three corner portions 7 are arranged on the upper surface 2. Here, as shown in FIG. 3, when viewed from the direction facing the upper surface 2, the corner portion 7 located in the lower left is referred to as a first corner portion 7 a, and the corner portion 7 located in the lower right is referred to as a second corner. This is referred to as part 7b. In more detail, an obtuse angle corner exists between the first corner portion 7a and the second corner portion 7b. However, the obtuse angle corner is ignored here, and the upper surface 2 is described as a substantially triangular shape. Such obtuse corners may not be present on the upper surface 2. On the contrary, the upper surface 2 may have a complicated contour shape in which more corners exist. The radius of curvature of the corner portion 7 of the cutting insert 1 is about 0.8 mm.

In the cutting insert 1, a cutting edge 5 is formed at a part of an intersecting ridge line portion between the upper surface 2 and the peripheral side surface 4. The cutting edge 5 is formed along the intersecting ridge line portion between the upper surface 2 and the peripheral side surface 4. In the cutting insert 1, a part of the upper surface 2 functions as a rake face, a part of the peripheral side surface 4 functions as a flank face, and a cross ridge line portion between the rake face and the flank face functions as a cutting edge 5. The cutting edge 5 includes at least two parts 5a and 5b. Two portions 5 a and 5 b of the cutting edge 5 are formed between the adjacent corner portions 7 and 7. Here, the portion 5a is referred to as a main cutting edge 5a, and the portion 5b is referred to as a sub cutting edge 5b. The main cutting edge 5a and the sub cutting edge 5b are connected by a connecting portion 6. The cutting edge 5 includes a main cutting edge 5a, a connecting portion 6, and a sub cutting edge 5b in this order from the first corner portion 7a side to the second corner portion 7b side.

Since the shape of the cutting insert 1 is 120 ° rotationally symmetric, the cutting insert 1 is formed with three cutting edges 5. Moreover, the main cutting edge 5a and the subcutting edge 5b are formed so that each corner part 7 may be pinched | interposed. During cutting with the cutting insert 1, the main cutting edge 5a and the sub cutting edge 5b sandwiching one corner portion 7 function. The main cutting edge 5a and the sub cutting edge 5b sandwiching the main cutting edge 5a and the corner portion 7 intersect with each other at a substantially right angle or with an inner angle of 90 ° or less. More specifically, as shown in FIG. 3, the cutting insert 1 has a main cutting edge 5 a and a sub-cutting edge 5 b at an inner angle of about 89 ° with the corner portion 7 interposed therebetween when viewed from the direction facing the upper surface 2. Crossed. The cutting insert 1 having such a shape is suitable for right-angle shoulder machining. The sub cutting edge 5b can function as a front cutting edge. The auxiliary cutting edge 5b may be formed so as to include a finishing edge (wiper edge). Further, as shown in FIG. 3, the main cutting edge 5a is gently curved so as to protrude outward as viewed from the direction facing the upper surface 2. Thereby, the rotation locus of the main cutting edge 5a when the cutting insert 1 is mounted on the cutting tool becomes close to an accurate cylindrical shape.

As described above, the cutting insert 1 has three cutting edges 5. For this reason, even if one cutting edge 5 is used and it reaches the end of its life due to wear or the like, it is possible to continue using the cutting insert 1 by replacing the position with the other cutting edge 5. Each cutting edge 5 has the same function. Therefore, in order to simplify the description, only one cutting edge 5 will be described below, and description of the other two cutting edges 5 will be omitted. In addition, for the upper surface 2 and the like, only the part around the one cutting edge 5 will be described, and the explanation about the part around the other cutting edge 5 will be omitted.

In the cutting insert 1, the diameter of the inscribed circle of the substantially triangular upper surface 2 is about 14 mm. The length of one side of the upper surface 2 is about 16 mm. The thickness of the cutting insert 1 is about 6 mm. Each dimension of the cutting insert 1 is adjusted timely according to the shape of the workpiece, cutting conditions, and the like. Further, the cutting insert 1 has a cutting edge 5 formed only at a part of the intersecting ridge line portion between the upper surface 2 and the peripheral side surface 4. However, the cutting edge 5 may be formed in the whole area | region of a crossing ridgeline part. That is, the entire area of the connecting portion 6 may function as the cutting edge 5.

The peripheral side surface 4 intersects with the lower surface 3 at an obtuse angle at an internal angle. The cutting insert 1 is a so-called positive type as a whole. However, the peripheral side surface 4 has a portion that intersects the upper surface 2 at an acute angle and a portion that intersects an obtuse angle. Specifically, the portion of the peripheral side surface 4 connected to the secondary cutting edge 5b intersects the upper surface 2 at an acute angle, and the portion of the peripheral side surface 4 connected to the main cutting edge 5a intersects the upper surface 2 at an obtuse angle. That is, a portion of the peripheral side surface 4 that is connected to the main cutting edge 5a is formed so that the clearance angle is negative. And the part which connects to the corner part 7 and the connection part 6 among the surrounding side surfaces 4 is changing gradually between the acute angle and an obtuse angle with the upper surface 2. FIG. Therefore, as shown in FIG. 5, when the cutting insert 1 is viewed from the direction facing the end surface 2, a part of the peripheral side surface 4 connected to the main cutting edge 5a can be seen. A clearance angle of a portion of the peripheral side surface 4 connected to the main cutting edge 5a is approximately −3 °, which is substantially constant.

As shown in FIGS. 6 and 8, a virtual intermediate plane M is defined between the upper surface 2 and the lower surface 3. The intermediate plane M is preferably defined at the center between the upper surface 2 and the lower surface 3 in parallel with the lower surface 3. As shown in FIGS. 6 and 8, when the cutting insert 1 is viewed from the peripheral side surface 4 side in parallel with the lower surface 3, the main cutting edge 5 a is inclined with respect to the lower surface 3 and the intermediate plane M. The main cutting edge 5a has a first inclined portion 5a1. The first inclined portion 5a1 is inclined so as to approach the intermediate plane M from the first corner portion 7a side toward the second corner portion 7b side. Here, as shown in FIG. 6, the inclination angle formed by the main cutting edge 5 a with respect to the lower surface 3 is referred to as “first inclination angle A”. The first inclination angle A of the cutting insert 1 is about 3 °.

As shown in FIG. 6, the connecting portion 6 smoothly connects the main cutting edge 5a and the auxiliary cutting edge 5b. The connecting portion 6 has a second inclined portion 6 a that is inclined with respect to the lower surface 3 and the intermediate plane M. In other words, the connection part 6 has the 2nd inclination part 6a which spaces apart from the intermediate plane M as it goes to the sub cutting edge 5b side from the main cutting edge 5a side. Here, as shown in FIG. 6, the inclination angle formed by the second inclined portion 6 a with respect to the lower surface 3 is referred to as “second inclination angle B”. The second inclination angle B of the cutting insert 1 is about 30 °.

As shown in FIG. 7, the connecting portion 6 has a linear portion 6b on the first inclined portion 5a1 side with respect to the second inclined portion 6a. The straight portion 6 b extends with a dimension L substantially parallel to the lower surface 3 and the intermediate plane M. The dimension L is a dimension in a direction parallel to the direction in which the lower surface 3 extends, and can be referred to as the length of the linear portion 6b. The length L of the linear portion 6b of the cutting insert 1 is about 0.5 mm.

3 to 5, the upper surface 2 has a land 8. The land 8 has a band shape and extends along the cutting edge 5 and the connecting portion 6. As shown in FIGS. 4 and 5, the land 8 includes a width-enlarging portion 8 a that increases in width as it goes from the main cutting edge 5 a side to the sub-cutting edge 5 b side in the portion along the connection portion 6.

Although not shown, the upper surface 2 is closer to the intermediate plane M as it is separated from the intersecting ridge line portion (the cutting blade 5 or the connecting portion 6) between the upper surface 2 and the peripheral side surface 4 in the cutting plane orthogonal to the main cutting edge 5a. It has an inclined part. That is, at least a part of the upper surface 2 has a positive rake angle. Here, the rake angle of the land 8 portion is referred to as “the inclination angle of the land 8”. That is, the inclination angle of the land 8 is also called a rake angle. The reference (0 °) of the angle of the cutting insert 1 alone for the rake angle and the inclination angle of the land 8 can be a reference line parallel to the lower surface 3. The rake angle of the cutting insert 1 and the inclination angle of the land 8 are substantially constant over the entire circumference of the cutting edge 5 and the connection portion 6. However, the rake angle and the inclination angle of the land 8 may be provided so as to change along the cutting edge 5 or the connecting portion 6. For example, the rake angle in the vicinity of the main cutting edge 5a of the connecting portion 6 and the inclination angle of the land 8 may be smaller than the rake angle in the vicinity of the first corner portion 7a of the main cutting edge 5a.

The material of the cutting insert 1 is a cemented carbide, cermet, ceramics and cubic boron nitride, a material in which the surface of these hard materials is coated, or diamond at least near the cutting edge 5. In addition, it is preferable that the material of parts other than the cutting edge 5 vicinity is also the same hard material.

The cutting insert 1 having the above-described configuration is attached to the tool body 21 of the cutting tool 20 as shown in FIG. The cutting tool 20 is a rotary cutting tool. More specifically, the cutting tool 20 is a luffing cutter capable of performing right-angle shoulder machining. The cutting insert 1 is detachably attached to the tool body 21 using a clamp member that is a mechanical attachment means. Hereinafter, the cutting tool 20 will be further described with reference to FIG. The cutting tool 20 uses a clamping screw 24 as a clamp member.

The cutting tool 20 includes a tool body 21 in which a plurality of (here, 20 in 4 rows and 5 stages) chip seats 22 are formed. One cutting insert 1 can be detachably mounted on each chip seat 22. Although not shown, the present invention does not exclude a cutting tool including a tool body provided with only one chip seat.

The tool body 21 is formed in a substantially cylindrical shape as a whole. The tool body 21 is configured to rotate around the central axis AX. The center axis AX is determined so as to penetrate the tool body 21 from the front end 21a to the rear end 21b side. Hereinafter, the direction in which the tip seat 22 advances as the tool body 21 rotates is referred to as “forward in the rotational direction”.

The four tip seats 22 are formed at equal intervals on the tip 21a of the tool body 21. A chip pocket 23 is formed in front of each chip seat 22 in the rotational direction. Each chip pocket 23 extends spirally from the front end 21a toward the rear end 21b. Along the chip pockets 23, five chip seats 22 are arranged stepwise. The plurality of cutting inserts 1 used in the cutting tool 20 all have the same configuration and the same shape. However, the shape of the plurality of chip seats 22 may be slightly different depending on the position on the tool body 21. In particular, the shape of the tip seat 22 arranged closest to the tip 21 a is different from the shape of the tip seat 22 arranged closer to the rear end 21 b than the tip seat 22. The tip seat 22 arranged on the most distal end 21a side is formed such that the auxiliary cutting edge 5b of the cutting insert 1 functions as a front edge. On the other hand, in the tip seat 22 on the rear end 21b side, the auxiliary cutting edge 5b does not function as a front edge.

The cutting insert 1 is mounted on each chip seat 22 of the tool body 21 so that the upper surface 2 faces forward in the rotational direction. Although not shown, each chip seat 22 has a bottom surface and a wall surface, and is open toward the outer peripheral side of the tool body 21. Further, the tip seat 22 arranged on the most distal end 21 a side is also opened toward the distal end 21 a side of the tool body 21. Here, the surface with which the lower surface 3 of the cutting insert 1 contacts is referred to as the bottom surface of the chip seat 22. Further, the surface with which the peripheral side surface 4 of the cutting insert 1 contacts is referred to as the wall surface of the tip seat 22. Therefore, the bottom surface faces forward in the rotational direction. The cutting insert 1 is disposed on the chip seat 22 so that a pair of main cutting edges 5a and sub cutting edges 5b sandwiching one corner portion 7 can be used, and is fixed by a fastening screw. The bottom surface of the chip seat 22 is formed with a screw hole into which the fastening screw 24 is screwed.

Next, operations and effects of the cutting insert 1 and the cutting tool 20 including the cutting insert 1 will be described. Moreover, the preferable form of the cutting insert 1 is also demonstrated.

The cutting insert 1 has a first inclined portion 5 a 1 whose main cutting edge 5 a is inclined with respect to the lower surface 3. For this reason, the main cutting edge 5a is suitable for reducing cutting resistance or improving chip dischargeability. Moreover, the cutting insert 1 has the linear part 6b in the connection part 6 between the main cutting edge 5a and the subcutting edge 5b. As shown in FIG. 7, the inclination angle (0 °) formed by the linear portion 6b with respect to the lower surface 3 is smaller than the inclination angle A (3 °) formed by the first inclined portion 5a1 with respect to the lower surface 3. The connection part 6 has the linear part 6b on the main cutting edge 5a side. This prevents the connecting portion 6 from rising steeply with respect to the first inclined portion 5a1 of the main cutting edge 5a. As a result, the connecting portion 6 does not hinder the discharge of the chips generated by the main cutting edge 5a, and the chips are discharged smoothly. Furthermore, it is prevented that chipping and chipping occur from the connection portion 6 due to accumulation of chips, and the tool life of the cutting insert 1 is extended.

In order to obtain such actions and effects, a linear portion 6b having a sufficient length is required. The length L of the linear portion 6b is preferably in the range of 0.2 mm or more and 5 mm or less. If the length L of the linear portion 6b is less than 0.2 mm, chips cannot be discharged smoothly, and defects and chipping are likely to occur from the connection portion 6. On the other hand, since the connection part 6 is a part which connects the main cutting edge 5a and the sub-cutting edge 5b, if the length L of the linear part 6b exceeds 5 mm, the cutting insert 1 will become large too much. As described above, the cutting insert 1 has the linear portion 6 b parallel to the lower surface 3. For this reason, as shown in FIG. 7, the length L of the linear part 6b corresponds to the length in the direction parallel to the direction in which the lower surface 3 extends. Although not shown, even when the linear portion 6b is inclined with respect to the lower surface 3, the length in a direction parallel to the direction in which the lower surface 3 extends in front view may be determined as the length L of the linear portion 6b.

Incidentally, when the inclination angle B shown in FIG. 6 is 0 ° or a negative angle, it is difficult to provide a plurality of cutting edges 5 while having the auxiliary cutting edges 5b. That is, it is difficult to connect the second inclined portion 6a to the auxiliary cutting edge 5b unless the second inclined portion 6a is inclined in the opposite direction to the first inclined portion 5a1. Further, when the inclination angle B exceeds 40 °, the second inclined portion 6a rises sharply with respect to the first inclined portion 5a1 of the main cutting edge 5a, so that chip discharge is easily inhibited. If the discharge of chips is hindered, chips are likely to accumulate around the connection portion 6, and defects and chipping are likely to occur from the connection portion 6.

Therefore, it is preferable that the inclination angle B is larger than 0 ° and not more than 40 °. This prevents the second inclined portion 6a of the connecting portion 6 from rising sharply with respect to the inclined portion 5a1 of the main cutting edge 5a.

Note that the connecting portion 6 may be provided with a plurality of inclined portions in stages. When a plurality of inclined portions are provided step by step, the inclined portion closest to the main cutting edge 5a may be the second inclined portion 6a, and the aforementioned inclination angle B may be used. Furthermore, it is preferable that the inclination angles of all the inclined portions are larger than 0 ° and not more than 40 °.

As described above, in the cutting insert 1, a portion of the peripheral side surface 4 that is connected to the main cutting edge 5a is formed so that the clearance angle is negative. Therefore, the strength of the main cutting edge 5a is high, and chipping and chipping hardly occur. The cutting insert 1 is attached to the cutting tool 20 so that the clearance angle of the main cutting edge 5a is positive.

When the upper surface 2 has the lands 8, the lands 8 preferably include a width-enlarging portion 8a whose width increases from the main cutting edge 5a side toward the sub-cutting edge 5b side. By increasing the width of the land 8, it is possible to prevent the connection portion 6 from being damaged or chipped. The width of the land 8 is preferably changed so as to be smoothly connected to the auxiliary cutting edge 5b. The width of the land 8 of the cutting insert 1 gradually changes in the portion connected to the connection portion 6. The width of the land 8 is about 0.1 mm at a portion connected to the main cutting edge 5a, and is about 0.3 mm at a portion connected to the sub cutting edge 5b.

When the widened portion 8a is included, the land 8 may further include a width-reduced portion (not shown) closer to the auxiliary cutting edge 5b than the widened portion 8a. The width reduction portion is a portion where the width decreases as it goes from the main cutting edge 5a side to the sub cutting edge 5b side. The land 8 includes both the width-enlarged portion 8a and the width-reduced portion, so that the width of the land 8 in the connecting portion 6 is increased without being restricted by the width of the land 8 in the main cutting edge 5a and the sub-cutting edge 5b. be able to. As a result, it is possible to prevent the chipping and chipping at the connection portion 6 where the chipping and chipping are most likely to occur. In addition, it is preferable that the width of the land 8 of the connection part 6 is the same as the width of the land 8 of the main cutting edge 5a in the part related to cutting. Moreover, it is preferable that the width expansion part 8a starts to expand in width from the linear part 6b or the arcuate part of the connecting part 6.

The rake angle in the vicinity of the main cutting edge 5a of the connecting portion 6 or the inclination angle of the land 8 is preferably smaller than the rake angle in the vicinity of the first corner portion 7a of the main cutting edge 5a. In other words, it is preferable that the rake angle at the connecting portion 6 or the inclination angle of the land 8 is smaller than the rake angle at the main cutting edge 5a. More preferably, the rake angle in the vicinity of the main cutting edge 5a of the connection portion 6 or the inclination angle of the land 8 is 0 °. By reducing the rake angle at the connecting portion 6 or the inclination angle of the land 8, the strength of the connecting portion 6 can be increased, and the occurrence of chipping or chipping from the connecting portion 6 can be prevented.

The cutting edge 5 and the connecting portion 6 may have honing (not shown). It is preferable that the size of the honing in the connection part 6 is larger than the size of the honing in the main cutting edge 5a. By increasing the size of the honing in the connection portion 6, the strength of the connection portion 6 can be increased and the occurrence of chipping or chipping from the connection portion 6 can be prevented. In addition, the dimension of a honing can also be represented by the width of the honing regarding the rake face side.

The cutting insert 1 is attached to the tool body 21 by a clamp member. As the clamp member, a known technique such as a wedge or a pressing piece can be applied. However, a roughing cutter such as the cutting tool 20 is required to discharge chips efficiently. Moreover, in the luffing cutter, it is required to reduce the cutting resistance in order to prevent chattering. In order to meet such a requirement, it is preferable to use a tightening screw 24 for mounting the cutting insert 1. By using the tightening screw 24, it is possible to easily attach the cutting insert 1 having a lower central surface portion to the cutting edge 5. Further, since there are no obstacles such as wedges or pressing pieces on the rake face side, chips can be discharged efficiently. Such a cutting tool can be used for cutting a steel material by being mounted on a machine tool.

Next, the cutting insert 101 according to the second embodiment will be described with reference to FIGS. 10 to 13. Of the configuration of the cutting insert 101, the same components as those of the cutting insert 1 according to the first embodiment are denoted by the same reference numerals, and description thereof is omitted. Hereinafter, in the structure of the cutting insert 101, a different part from the cutting insert 1 which concerns on 1st Embodiment is mainly demonstrated.

The cutting insert 101 includes an upper surface 2 and a lower surface 3 facing substantially opposite to each other, and a peripheral side surface 4 extending therebetween. As shown in FIG. 11, the cutting insert 101 has a substantially triangular shape when viewed from the direction facing the upper surface 2. An attachment hole 9 extending so as to penetrate the upper surface 2 and the lower surface 3 is formed.

The cutting edge 5 includes at least a main cutting edge 5a and a sub cutting edge 5b. The main cutting edge 5 a and the sub cutting edge 5 b are formed between the adjacent corner portions 7 and 7. As shown in FIG. 12, a virtual intermediate plane M is defined between the upper surface 2 and the lower surface 3. The main cutting edge 5a is inclined with respect to the lower surface 3 and the intermediate plane M when viewed in parallel with the lower surface 3 from the side surface 4 connected to the main cutting edge 5a. The main cutting edge 5a and the sub cutting edge 5b are connected via the connection part 102. The cutting edge 5 includes a main cutting edge 5a, a connecting portion 102, and a sub cutting edge 5b in this order from the first corner portion 7a side to the second corner portion 7b side.

As shown in FIG. 13, the connecting portion 102 smoothly connects the main cutting edge 5a and the sub cutting edge 5b. The connecting portion 102 has a second inclined portion 102 a that is inclined with respect to the lower surface 3 and the intermediate plane M. In other words, the connection part 102 has the 2nd inclination part 102a spaced apart from the intermediate plane M as it goes to the sub cutting edge 5b side from the main cutting edge 5a side. That is, as shown in FIG. 12, when viewed from the side of the peripheral side surface 4 connected to the main cutting edge 5a in parallel with the lower surface 3, the connecting portion 102 has a second slope that is separated from the lower surface 3 and the intermediate plane M toward the right side. It has a portion 102a. Here, as shown in FIG. 12, an inclination angle formed by the second inclined portion 102 a with respect to the lower surface 3 is referred to as a “second inclination angle B”. The second inclination angle B of the cutting insert 101 is about 30 °.

As shown in FIG. 13, the connecting portion 102 has an arcuate portion 102b formed in a substantially arcuate shape on the first inclined portion 5a1 side from the second inclined portion 102a. The arcuate portion 102b is an arc having a radius of curvature R. The curvature radius R is about 70 mm. However, since the radius of curvature R is large, the arc-shaped portion 102b looks almost linear with the naked eye. 10 to 13 schematically illustrate the roundness of the arcuate portion 102b with emphasis. Further, in FIGS. 10 to 13, the arcuate portion 102b is drawn so as to be smoothly connected to the second inclined portion 102a. Actually, another arcuate portion that smoothly connects them may be formed between the arcuate portion 102b and the second inclined portion 102a (not shown). As long as the arcuate part 102b corresponding to the linear part 6b in the first embodiment is formed, the other arcuate part may have any shape.

The cutting insert 101 having the above configuration can be detachably mounted on the same tool body 21 as the cutting tool 20 in the first embodiment. About the cutting tool with which the cutting insert 101 was mounted | worn, since it is the same as that of the cutting tool 20 in 1st Embodiment, description is abbreviate | omitted.

Next, the operation and effect of the cutting insert 101 will be described. Moreover, the preferable form of the cutting insert 101 is also demonstrated.

The cutting insert 101 has the 1st inclination part 5a1 in which the main cutting edge 5a inclines with respect to the lower surface 3 similarly to the cutting insert 1 in 1st Embodiment. In addition, the connection portion 102 between the main cutting edge 5a and the sub cutting edge 5b has an arcuate portion 102b having a curvature radius R. Since the connecting portion 102 has the arcuate portion 102b, it is prevented that the connecting portion 102 rises sharply with respect to the first inclined portion 5a1 of the main cutting edge 5a. Thereby, the connection part 102 does not inhibit the discharge | emission of the chip | tip produced | generated with the main cutting edge 5a, and a chip | tip is discharged | emitted smoothly. As a result, it is possible to prevent the chipping and chipping from occurring at the connection portion 102 due to the accumulation of chips.

The arc-shaped portion 102b having a large curvature radius R can obtain the same operations and effects as the linear portion 6b of the cutting insert 1 according to the first embodiment. The radius of curvature R of the arcuate portion 102b is preferably in the range of 5 mm or more and 1000 mm or less. The curvature radius R is more preferably in the range of 50 mm or more and 1000 mm or less. If the curvature radius R is less than 5 mm, chip discharge may be hindered. When the radius of curvature R is 50 mm or more, substantially the same operation and effect as the linear portion 6b can be obtained.

The embodiments of the cutting insert and the cutting tool have been described above. However, the scope of the present invention is not limited to the above-described embodiment.

For example, the present invention can be applied to a cutting insert having a nick. Moreover, although the main cutting edge was made into linear form, you may be made into the wavy main cutting edge from which an inclination angle fluctuates. Further, the present invention is not limited to a luffing cutter capable of cutting right shoulders, but can be applied to a face mill with various cutting edge angles, a disk-shaped side cutter, and the like. The present invention can be applied not only to the rolling tool as in the above embodiment, but also to other types of cutting tools such as a turning tool and a drilling tool.

Moreover, the connection part 6 which concerns on 1st Embodiment mentioned above has the linear part 6b. On the other hand, the connecting portion 102 according to the second embodiment has an arcuate portion 102b. However, the present invention is not limited to these embodiments. That is, the connection part according to the present invention may have both a linear part and an arc-shaped part.

Although the present invention has been described with a certain degree of specificity in the above-described embodiment and its modifications, the present invention is not limited to the above-described embodiment. It should be understood that various changes and modifications can be made to the present invention without departing from the spirit and scope of the claimed invention. That is, the present invention includes all modifications, applications, and equivalents included in the concept of the present invention defined by the claims.

1 Cutting insert 2 First end face (upper surface)
3 Second end face (lower face)
4 peripheral side surface 5 cutting edge 5a first cutting edge (main cutting edge)
5a1 First inclined portion 5b Second cutting edge (sub cutting edge)
6 connecting portion 6a second inclined portion 6b linear portion 7 corner portion 7a first corner portion 7b second corner portion 8 land 8a widened portion 9 mounting hole 20 cutting tool 101 cutting insert 102 connecting portion 102a second Inclined portion 102b Arc-shaped portion A First angle B Second angle C Reference axis L of cutting insert Straight portion length M Intermediate plane R Radius of curvature of arc-shaped portion

Claims (13)

A cutting insert (1) mounted on a cutting tool,
A first end face (2) having a first corner portion (7a) and a second corner portion (7b);
A second end face (3) facing away from the first end face (2);
A peripheral side surface (4) extending between the first end surface (2) and the second end surface (3);
A cutting edge (5) that forms at least a part of an intersecting ridge line portion between the first end surface (2) and the peripheral side surface (4),
The cutting edge (5) includes a first cutting edge (5a) and the first cutting edge (5a) between the first corner portion (7a) and the second corner portion (7b). And a second cutting edge (5b) disposed on the opposite side of the first corner (7a),
The first cutting edge (5a) and the second cutting edge (5b) are connected to each other via a connection portion (6),
When defining an intermediate plane (M) disposed between the first end face (2) and the second end face (3) and intersecting the peripheral side face (4),
The first cutting edge (5a) has a first inclined portion (5a1) that approaches the intermediate plane (M) as it is separated from the first corner portion (7a),
The connecting portion (6) includes a second inclined portion (6a) that is separated from the intermediate plane (M) as it is separated from the first cutting edge (5a), and the second inclined portion (6a). A linear portion (6b) extending linearly in side view between the first inclined portions (5a1);
In the side view, the linear part (6b) is a cutting insert having an inclination angle with respect to the second end face (3) smaller than an inclination angle (A) of the first inclined part (5a1). The cutting insert according to claim 1, wherein the linear portion (6b) is substantially parallel to the second end surface (3) in a side view. The length (L) of the linear portion (6b) in a direction parallel to the direction in which the second end surface (3) extends in a side view is in the range of 0.2 mm or more and 5 mm or less. Or the cutting insert of 2. A cutting insert (101) attached to a cutting tool,
A first end face (2) having a first corner portion (7a) and a second corner portion (7b);
A second end face (3) facing away from the first end face (2);
A peripheral side surface (4) extending between the first end surface (2) and the second end surface (3);
A cutting edge (5) forming at least a part of an intersecting ridge line portion between the first end surface (2) and the peripheral side surface (4),
The cutting edge (5) includes a first cutting edge (5a) and the first cutting edge (5a) between the first corner portion (7a) and the second corner portion (7b). And a second cutting edge (5b) disposed on the opposite side of the first corner (7a),
The first cutting edge (5a) and the second cutting edge (5b) are connected to each other via a connection portion (102),
When defining an intermediate plane (M) disposed between the first end face (2) and the second end face (3) and intersecting the peripheral side face (4),
The first cutting edge (5a) has a first inclined portion (5a1) that approaches the intermediate plane (M) as it is separated from the first corner portion (7a),
The connecting portion (102) includes a second inclined portion (102a) that is separated from the intermediate plane (M) as it is separated from the first cutting edge (5a), and the second inclined portion (102a). An arcuate part (102b) extending so as to be curved in a substantially arcuate shape in a side view between the first inclined parts (5a1),
A cutting insert having a radius of curvature (R) in a range of 5 mm or more and 1000 mm or less when the arc-shaped portion (102b) is approximated by an arc in a side view. The angle of inclination (B) of the second inclined portion (6a, 102a) with respect to the second end surface (3) in a side view is in the range of greater than 0 ° and less than or equal to 40 °. The cutting insert according to any one of 4. The first end face (2) has a strip-shaped land (8) extending along the connecting portion (6, 102),
The land (8) includes a width-enlarging portion (8a) whose width increases from the first cutting edge (5a) side toward the second cutting edge (5b) side. The cutting insert according to claim 1. The land (8) is closer to the second cutting edge (5b) than the widened portion (8a) and from the first cutting edge (5a) to the second cutting edge (5b). The cutting insert according to claim 6, further comprising a width-reduced portion whose width decreases toward the head. In a cutting plane orthogonal to the first cutting edge (5a) when viewed from the direction facing the first end face (2), a straight line parallel to the second end face (3) is used as an angle reference, A positive rake angle when the first end surface (2) is inclined so as to approach the intermediate plane (M) as it is separated from the intersecting ridge line portion between the first end surface (2) and the peripheral side surface (4). The rake angle in the vicinity of the first cutting edge (5a) of the connection portion (6, 102) is in the vicinity of the first corner portion (7a) of the first cutting edge (5a). The cutting insert according to any one of claims 1 to 5, wherein the cutting insert is smaller than a rake angle. In a cutting plane orthogonal to the first cutting edge (5a) when viewed from the direction facing the first end face (2), a straight line parallel to the second end face (3) is used as an angle reference, When the inclination angle of the land (8) is a rake angle, the rake angle in the vicinity of the first cutting edge (5a) of the connecting portion (6, 102) is the rake angle of the first cutting edge (5a). The cutting insert according to claim 6 or 7, wherein the cutting angle is smaller than a rake angle in the vicinity of the first corner portion (7a). The cutting insert according to claim 8 or 9, wherein the rake angle in the vicinity of the first cutting edge (5a) of the connecting portion (6, 102) is 0 °. The cutting edge (5) and the connecting part (6, 102) have honing;
The cutting insert according to any one of claims 1 to 10, wherein a size of a honing in the connection portion (6, 102) is larger than a size of a honing in the first cutting edge (5a). A cutting tool comprising the cutting insert (1, 101) according to any one of claims 1 to 11. A plurality of the cutting inserts (1, 101);
The cutting tool according to claim 12, wherein at least two of the cutting inserts (1) are displaced from each other in the tool rotation axis direction.

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