Cutting insert and blade edge replaceable cutting tool

Abstract

To enable a cutting insert formed in a planar and square shape having long side parts and short side parts, in which lengths of the short side part are short, to be tightly mounted on a tool body using a fixed screw having a large diameter.SOLUTION: A cutting insert 10, which is formed in a planar and nearly square shape having long side parts 11 and short side part 12, is provided with an insertion hole 13 for fixing penetrating through central portions of a front face part 10a and of a rear face part 10b, in which corner cutting edges 14 are formed at two curved corner parts at respective diagonal positions at the front face part and the rear face part. Swollen parts 15 ejected in a circular arc-shape to outside in a radial direction of the insertion hole for fixing are provided at central parts of the long side parts at both sides in a linear shape opposing to each other at the front face part and the rear face part.SELECTED DRAWING: Figure 6

Description

[Technical field]

[0001] The present invention relates to a cutting insert that is attached to a tool body and used for cutting processing, and to an indexable cutting tool in which the cutting insert is detachably attached to the tool body. In particular, in an indexable cutting tool that uses a cutting insert having a planar rectangular shape having long and short sides, a fixing insertion hole penetrating the center of the front and back sides, and corner cutting edges formed at two curved corners at diagonal positions on the front and back sides, and that attaches the cutting insert to an insert pocket provided in the tool body by passing a fixing screw through the fixing insertion hole penetrating the center of the front and back sides of the cutting insert, and cuts a workpiece with the corner cutting edge, the cutting insert is characterized in that even when a cutting insert having a short short side length is used to attach the cutting insert to a tool body having a small tool diameter, the cutting insert can be firmly attached to the tool body using a fixing screw with a large diameter, and even if the hole diameter of the fixing insertion hole provided in the cutting insert is large, the cutting insert is prevented from being damaged during cutting processing, making it possible to stably perform high feed processing and the like. [Background technology]

[0002] Conventionally, as shown in Patent Documents 1 to 3, a cutting insert having a generally rectangular planar shape with long and short sides, a fixing insertion hole penetrating the center of the front and back portions, and corner cutting edges formed at two curved corners at diagonal positions on the front and back portions, is used, and a cutting insert is detachably attached to the tool body by a fixing screw through the fixing insertion hole penetrating the center of the front and back portions of the cutting insert, with the long side of the cutting insert aligned along the axial direction of the tool body.

[0003] Furthermore, when using a tool body with a small tool diameter to perform pocket machining with a narrow cutting width using an indexable cutting tool as described above, or when it is desired to increase the number of cutting edges for the purpose of highly efficient cutting, it is necessary to use a cutting insert with a short side length as the cutting insert to be attached to the tool body.

[0004] Here, in order to firmly attach a cutting insert having a short short side length as described above to the tool body with a fixing screw, if a fixing screw with a large diameter is used, it is necessary to increase the hole diameter of the fixing insertion hole that penetrates the center of the front and back surfaces of the cutting insert.

[0005] However, in cutting inserts having a short side length as described above, the distance between the fixing insertion hole and the long side of the cutting insert becomes narrow, reducing the strength between the fixing insertion hole and the long side of the cutting insert, resulting in problems such as damage to the cutting insert during cutting processing such as high feed processing.

[0006] Furthermore, in the prior art, as shown in Patent Document 4, a cutting insert has a generally rectangular planar shape having long and short sides, a fixing insertion hole penetrating the center of the front and back portions, and corner cutting edges formed at two curved corners on the front and back portions, in which the centers of both opposing straight long sides on the front and back portions are recessed.

[0007] However, when the central portions of both opposing straight-line long sides on the front and back surfaces are recessed in this manner, in a cutting insert having a short short side length as described above, the space between the fixing insertion hole and the long side of the cutting insert becomes narrow, resulting in a significant reduction in the strength between the fixing insertion hole and the long side of the cutting insert.

[0008] Furthermore, when the cutting insert is attached to the insert pocket of the tool body as described above and the corner cutting edge of the cutting insert is used to cut the workpiece, a large load is applied to the mounting surface of the insert pocket that comes into contact with the cutting insert, particularly to the corner portion on the inner tip side of the mounting surface of the insert pocket, which can cause damage to the tip of the tool body. [Prior art documents] [Patent documents]

[0009] [Patent Document 1] Patent No. 5007853 [Patent Document 2] Patent No. 6507355 [Patent Document 3] Patent No. 7417713 [Patent Document 3] Patent No. 7197576 DISCLOSURE OF THEINVENTION [Problem to be solved by the invention]

[0010] The present invention aims to solve the above-mentioned problems in an indexable cutting tool, which uses a cutting insert that has a roughly rectangular shape when viewed from above, having long and short sides, a fixing insertion hole that penetrates the center of the front and back portions, and has corner cutting edges formed at two curved corners at diagonally opposite positions on the front and back portions, and in which the long sides of the cutting insert are oriented along the axial direction of the tool body, a fixing screw is passed through the fixing insertion hole that penetrates the center of the front and back portions of the cutting insert, and the cutting insert can be detachably attached to the tool body by the fixing screw.

[0011] That is, in the indexable cutting tool as described above, when a cutting insert having a substantially rectangular shape in plan view having long and short sides and a short short side length is firmly attached to a tool body with a large-diameter fixing screw, even if the diameter of the fixing through hole penetrating the center of the front and back sides of the cutting insert is increased, the distance between the fixing through hole and the long side of the cutting insert does not become narrow, and the strength between the fixing through hole and the long side of the cutting insert does not decrease, so that the cutting insert can be appropriately prevented from being damaged during cutting processing such as high-feed processing, and when the cutting insert is attached to an insert pocket of the tool body and the workpiece is cut by the corner cutting edge of the cutting insert, a large load is applied to the mounting surface of the insert pocket that comes into contact with the cutting insert, particularly to the corner portion on the inner periphery of the tip of the mounting surface of the insert pocket, which prevents the tip of the tool body from being damaged. [Means for solving the problem]

[0012] In order to solve the above-mentioned problems, the cutting insert of the present invention has a generally rectangular planar shape having long and short sides, a fixing hole penetrating the center of the front and back sides, and corner cutting edges formed at two curved corners at diagonally opposite positions on the front and back sides, and has a bulge portion that protrudes in an arc shape radially outward from the fixing hole in the center of both opposing straight long sides on the front and back sides.

[0013] Here, as in the cutting insert of the present invention, by providing a bulge portion that protrudes in an arc shape radially outward from the fixing hole in the center of both opposing straight-line long side portions of the front and back surfaces, even if the diameter of the fixing hole that penetrates the center of the front and back surfaces of the cutting insert is increased, the space between the fixing hole and the long side portion of the cutting insert is prevented from narrowing, and a decrease in strength between the fixing hole and the long side portion of the cutting insert is prevented.

[0014] In addition, in the indexable cutting tool of the present invention, a cutting insert is used that has a generally rectangular shape in plan view having long and short sides, a fixing insertion hole that penetrates the center of the front and back parts, and corner cutting edges are formed at two curved corners at diagonal positions on the front and back parts, and a fixing screw is passed through the fixing insertion hole that penetrates the center of the front and back parts of the cutting insert to attach the cutting insert into an insert pocket provided in the tool body, and a workpiece is cut by the corner cutting edges.In this indexable cutting tool, a cutting insert is used that has a bulge that protrudes in an arc shape radially outward from the fixing insertion hole in the center of both long sides that are linearly opposed to each other on the front and back parts of the cutting insert, and when the cutting insert is attached in the insert pocket of the tool body, the corner cutting edges located on the outer periphery of the tip of the cutting insert are located on the outer periphery of the tool body relative to the bulge in the center of the long sides.

[0015] Furthermore, when a cutting insert is used in which a bulge protruding in an arc shape radially outward from the fixing hole is provided in the center of both opposing straight-line long sides of the front and back surfaces of the cutting insert, as in the case of the indexable cutting tool of the present invention, even if the diameter of the fixing hole penetrating the center of the front and back surfaces of the cutting insert is increased, the strength between the fixing hole and the long sides of the cutting insert is not reduced, and the cutting insert can be firmly attached to the tool body using a large-diameter fixing screw, making it possible to appropriately prevent the cutting insert from being damaged during cutting operations such as high-feed processing.

[0016] Furthermore, as in the case of the indexable cutting tool of the present invention, when the cutting insert is attached to the tool body, the corner cutting edge located on the outer periphery of the tip of the cutting insert is located on the outer periphery of the tool body further from the bulge in the center of the long side. Therefore, when the corner cutting edge of the cutting insert is used to perform pocket machining or the like on a workpiece, the bulge in the center of the long side does not protrude outward beyond the corner cutting edge performing the cutting and hit the wall of the workpiece, and the corner cutting edge of the cutting insert can properly cut the wall of the workpiece.

[0017] Furthermore, in the indexable cutting tool of the present invention, when the cutting insert is mounted in the insert pocket provided at the tip of the tool body, a recess that does not come into contact with the cutting insert can be provided at the tip of the tool body on the mounting surface of the insert pocket where the cutting insert is attached.

[0018] Furthermore, as with the above-mentioned indexable cutting tool, if a recess that does not come into contact with the cutting insert is provided at the tip of the tool body on the mounting surface of the insert pocket to which the cutting insert is attached, when the workpiece is cut with the corner cutting edge of the cutting insert, the load applied to the mounting surface of the insert pocket to which the cutting insert is attached, which is particularly prone to damage, is reduced, thereby preventing damage to the tip of the tool body.

[0019] Furthermore, in the indexable cutting tool of the present invention, the cutting insert has a recess that is lower in the thickness direction than the front and back surfaces at each corner where the corner cutting edge is formed, and when the cutting insert is attached to an insert pocket of the tool body, the recess in the cutting insert can be prevented from contacting the mounting surface of the insert pocket provided in the tool body.

[0020] In this way, when the cutting insert is attached to the insert pocket so that the recess in the cutting insert does not come into contact with the mounting surface of the insert pocket provided in the tool body, when the workpiece is cut using the corner cutting edge of the cutting insert, the load applied to the mounting surface of the insert pocket in which the cutting insert is attached, particularly to the corner portions on the inner tip side of the mounting surface of the insert pocket which are prone to damage, is reduced, preventing damage to the tip of the tool body.

[0021] In particular, in the indexable cutting tool of the present invention, if three or more insert pockets are provided circumferentially at the tip of the tool body, the thickness of the tool body between the insert pockets becomes thin, the strength between the insert pockets weakens, and the tip of the tool body becomes more susceptible to damage. Therefore, it is preferable to provide a recess that does not come into contact with the cutting insert at the tip of the tool body on the mounting surface of the insert pocket where the cutting insert is attached as described above, and to use a cutting insert with a recess provided at each corner where the corner cutting edge is formed. Effect of the Invention

[0022] In the cutting insert and indexable cutting tool of the present invention, a cutting insert is used that has a planar, approximately rectangular shape having long and short sides, a fixing insertion hole that penetrates the center of the front and back sides, and corner cutting edges formed at two curved corners at diagonal positions on the front and back sides.A fixing screw is passed through the fixing insertion hole that penetrates the center of the front and back sides of the cutting insert, and the cutting insert is attached to an insert pocket provided in the tool body.The corner cutting edge located on the outer periphery of the tip of the cutting insert is positioned closer to the outer periphery of the tool body than the bulge in the center of the long sides, and the corner cutting edge cuts the workpiece.

[0023] As a result, when the cutting insert and replaceable cutting tool of the present invention are used, even if the diameter of the fixing insertion hole that penetrates the center of the front and back surfaces of the cutting insert is increased, the strength between the fixing insertion hole and the long side of the cutting insert is not reduced, and the cutting insert can be firmly attached to the tool body using a fixing screw with a large diameter, making it possible to properly prevent the cutting insert from being damaged during cutting processing such as high feed processing.In addition, when pocket processing or the like is performed on a workpiece using the corner cutting edge of the cutting insert, the bulge portion in the center of the long side does not protrude outward beyond the corner cutting edge and hit the wall of the workpiece, and the wall of the workpiece can be properly cut by the corner cutting edge of the cutting insert, making it possible to properly perform pocket processing or the like. [Brief description of the drawings]

[0024] [Figure 1] 1 is a schematic plan view showing a cutting insert according to an embodiment of the present invention. [Diagram 2] FIG. 2 is a schematic side view showing the cutting insert according to the embodiment. [Diagram 3] FIG. 2 is a schematic perspective view showing the cutting insert according to the embodiment. [Figure 4] FIG. 1 is a schematic explanatory diagram showing a state in which three insert pockets for attaching the cutting insert are provided in the circumferential direction on the outer periphery of the tip of a tool body in an indexable cutting tool using the cutting insert according to the embodiment. [Diagram 5] FIG. 2 is a partial schematic explanatory diagram showing the state before one side (back side) of a cutting insert is placed on the mounting surface of an insert pocket provided on the outer periphery of the tip of the tool body in the indexable cutting tool. [Figure 6] This is a partial schematic explanatory diagram showing the state in which, in the above-mentioned indexable cutting tool, a cutting insert is attached to the mounting surface of an insert pocket provided in the tool body, so that the corner cutting edge located on the outer periphery of the tip of the surface of the cutting insert is located on the outer periphery of the tool body rather than the bulge in the center of the long side on the outer periphery. BEST MODE FOR CARRYING OUT THEINVENTION

[0025] Hereinafter, the cutting insert and the indexable rotary cutting tool according to the embodiment of the present invention will be specifically described with reference to the attached drawings. Note that the cutting insert and the indexable rotary cutting tool according to the present invention are not limited to the following embodiments, and can be appropriately modified within the scope of the present invention.

[0026] In the cutting insert 10 of this embodiment, as shown in Figures 1 to 3, the cutting insert 10 is formed in a generally rectangular shape in plan view having a long side portion 11 and a short side portion 12, and a fixing insertion hole 13 is provided so as to penetrate the center of the generally rectangular front surface portion 10a and back surface portion 10b. Corner cutting edges 14 are provided at two curved corners extending from the long side portion 11 to the short side portion 12 at diagonal positions on the front surface portion 10a and back surface portion 10b, respectively.

[0027] In the cutting insert 10 of this embodiment, the front surface portion 10a and the back surface portion 10b are provided with bulges 15 projecting in an arc shape radially outward from the fixing insertion hole 13 at the center of the opposing straight long side portions 11 on both sides. By providing the bulges 15 projecting in an arc shape radially outward from the fixing insertion hole 13 at the center of the opposing straight long side portions 11 on both sides in this manner, even if the hole diameter of the fixing insertion hole 13 is increased, the interval between the fixing insertion hole 13 and the long side portion 11 of the cutting insert 10 becomes small, and a decrease in strength at this portion is prevented.

[0028] Furthermore, in the cutting insert 10 of this embodiment, recesses 16 are provided at the corners of the front surface portion 10a and the back surface portion 10b on which the corner cutting edge 14 is formed, the recesses 16 being lower in the thickness direction than the front surface portion 10a and the back surface portion 10b, respectively.

[0029] Here, in the indexable cutting tool of this embodiment, as shown in FIG. 4, three insert pockets 21 for attaching the cutting insert 10 are provided in the circumferential direction on the outer periphery of the tip of the tool body 20.

[0030] Then, as shown in Figures 5 and 6, one side (back surface portion 10b) of the cutting insert 10 is placed on the mounting surface 21a of each insert pocket 21, and a fixing screw 22 is screwed into a mounting hole 23 provided on the mounting surface 21a of each insert pocket 21 through a fixing insertion hole 13 provided to penetrate the center of the front surface portion 10a and the back surface portion 10b of each cutting insert 10, thereby mounting each cutting insert 10 within each insert pocket 21 provided in the tool body 20.

[0031] Here, when each cutting insert 10 is thus mounted in each insert pocket 21 provided in the tool body 20, as shown in Figure 6, the corner cutting edge 14 located on the outer periphery of the tip of the surface portion 10a that performs cutting in the cutting insert 10 is mounted so as to be located on the outer periphery of the tool body 20 relative to the bulge portion 15 in the center of the long side portion 11 on the outer periphery.

[0032] In this way, when the indexable cutting tool of this embodiment is rotated to perform cutting such as pocket machining on a workpiece (not shown) using each corner cutting edge 14 located on the outer periphery of the tip of each cutting insert mounted in each insert pocket 21 of the tool body 20, the bulge portion 15 provided in the center of the long side portion 11 on the outer periphery of each cutting insert will not come into contact with the wall of the workpiece.

[0033] As a result, in the indexable cutting tool of this embodiment, even if the hole diameter of the fixing insertion hole 13 is increased as described above, the distance between the fixing insertion hole 13 and the long side portion 11 of the cutting insert 10 does not become small, and the strength of this portion does not decrease. The cutting insert 10 can be firmly attached to the insert pocket 21 of the tool body 20 using a large-diameter fixing screw 22. This makes it possible to properly prevent the cutting insert 10 from being damaged during cutting processes such as high-feed processing. In addition, when cutting processes such as pocket machining are performed on a workpiece using the corner cutting edge 14 of the cutting insert 10, the bulge portion 15 in the center of the long side portion 11 will not hit the wall of the workpiece, and the corner cutting edge 14 of the cutting insert 10 can properly perform cutting processes such as pocket machining on the workpiece.

[0034] In addition, in the insert pocket 21 in which the cutting insert 10 is attached, a recess 21b is provided at the tip of the tool body 20 on the mounting surface 21a on which one side (rear surface 10b) of the cutting insert 10 is placed, so as not to come into contact with the one side (rear surface 10b) of the cutting insert 10.

[0035] In this manner, when the indexable cutting tool is rotated as described above and cutting is performed on a workpiece (not shown) using each corner cutting edge 14 located on the outer periphery of the tip of each cutting insert mounted in each insert pocket 21 of the tool body 20, the load applied to the mounting surface 21a of the insert pocket 21 in which the cutting insert 10 is mounted, particularly to the tip portion of the mounting surface 21a of the insert pocket 21 which is prone to damage, is reduced, and damage to the tip portion of the tool body 20 is prevented.

[0036] Furthermore, in the indexable cutting tool of this embodiment, the cutting insert 10 has recesses 16 provided at the corners of the front surface 10a and the back surface 10b on which the corner cutting edge 14 is formed as described above. Therefore, when the cutting insert 10 is attached by placing one side (back surface 10b) on the mounting surface 21a of the insert pocket 21, the recess 16 on the back surface 10b of the cutting insert 10 does not come into contact with the mounting surface 21a of the insert pocket 21 of the tool body 20.

[0037] When each cutting insert 10 is attached to the insert pocket 21 of the tool body 20 in this manner, when the indexable cutting tool is rotated as described above and cutting is performed on a workpiece (not shown) using each corner cutting edge 14 located on the outer periphery of the tip of each cutting insert attached in each insert pocket 21 of the tool body 20, the load applied to the mounting surface 21a of the insert pocket 21 to which the cutting insert 10 is attached is reduced, and in particular the load on the corner portion on the inner periphery of the tip of the mounting surface 21a of the insert pocket 21, which is prone to damage during cutting, is reduced, preventing damage to the portion between the insert pockets 21 at the tip of the tool body 20.

[0038] In the indexable cutting tool of this embodiment, an oil hole 24 for spraying cutting oil is provided in the insert pocket 21 of the tool body 20. [Explanation of symbols]

[0039] 10: Cutting insert 10a: Surface part 10b: Back part 11: Long side 12: Short side 13: Fixing hole 14: Corner cutting edge 15:bulge 16: Recess 20: Tool body 21: Insert pocket 21a: Mounting surface 21b: Relief section 22: Fixing screw 23: Mounting hole 24: Oil hole

Claims

1. A cutting insert having a generally rectangular planar shape having long and short sides, a fixing insertion hole penetrating the center of the front and back portions, and corner cutting edges formed at two curved corners at diagonal positions on each of the front and back portions, characterized in that the cutting insert has a bulge portion that protrudes in an arc shape radially outward from the fixing insertion hole in the center of both opposing straight-line long sides of the front and back portions.

2. The cutting insert according to claim 1, characterized in that a recess is provided on the front surface and back surface of each corner where the corner cutting edge is formed, the recess being lower in the thickness direction than the front surface and back surface, respectively.

3. 1. An indexable cutting tool using a cutting insert having a generally rectangular shape in plan view having long and short sides, a fixing insertion hole penetrating the center of a front portion and a back portion, and corner cutting edges formed at two curved corners at diagonal positions on the front portion and the back portion, wherein a fixing screw is passed through the fixing insertion hole penetrating the center of the front portion and the back portion of the cutting insert to mount the cutting insert in an insert pocket provided in a tool body, and the corner cutting edges cut a workpiece.

2. An indexable cutting tool using a cutting insert having a bulge portion that protrudes in an arc shape radially outward from the fixing insertion hole in the center of both long sides that are linearly opposed to each other on the front portion and the back portion of the cutting insert, wherein, when the cutting insert is mounted in the insert pocket of the tool body, the corner cutting edges located on the outer periphery of the tip of the cutting insert are located on the outer periphery of the tool body relative to the bulge portion in the center of the long sides.

4. 4. The indexable cutting tool according to claim 3, wherein when the cutting insert is mounted in an insert pocket provided at the tip of the tool body, a recess that does not come into contact with the cutting insert is provided at the tip of the tool body on the mounting surface of the insert pocket to which the cutting insert is attached.

5. 4. The indexable cutting tool according to claim 3, wherein the cutting insert has a recess that is lower in the thickness direction than the front and back surfaces of each corner where the corner cutting edge is formed, and when the cutting insert is attached to an insert pocket provided at the tip of the tool body, the recess in the cutting insert does not come into contact with the mounting surface of the insert pocket provided in the tool body.

6. 6. The indexable cutting tool according to claim 4 or 5, wherein three or more of the insert pockets are provided in the tip portion of the tool body in the circumferential direction of the tool body.

Images