Cutting insert and cutting tool

Abstract

To provide a cutting insert and a cutting tool that can achieve both cost reduction and flatness of a seating surface by eliminating a grinding step for a lower surface including the seating surface when applied to a cutting insert of one surface.SOLUTION: A cutting insert 1 is a plate-like cutting insert 1 having a center line O, which comprises: an upper surface 2 constituting one of surfaces opposite to each other along the center line O in an axial direction; a lower surface 3 constituting the other of the surfaces opposite to each other; a side surface 4 that connects the upper surface 2 and the lower surface 3 in the axial direction; and a fitting hole 6 formed through in the axial direction. The side surface 4 inclines to extend inside in a radial direction perpendicular to the center line O from the upper surface 2 to the lower surface 3 in the axial direction. The lower surface 3 has a seating surface 3a having a flat surface perpendicular to the center line O, and a pedestal 3b having a projected part projected on the outer peripheral edge of the seating surface 3a so as to be away more from the upper surface than the seating surface 3a in the axial direction. A top 3bc of the projected part of the pedestal 3b is perpendicular to the center line O.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present invention relates to a cutting insert and a cutting tool.

Background Art

[0002] Generally, in the manufacturing process of a single-sided cutting insert such as those in Patent Documents 1 and 2, a powder mixture of a hard metal component and a binder is press-molded to produce a compact for a cutting insert, and this compact for a cutting insert is sintered while being placed on a sintered plate. As described in Patent Document 3, although a contact reaction inhibitor is applied to the carbon sintered plate, unevenness due to the adhesion of the contact reaction inhibitor and sintering reaction marks is formed on the portion of the cutting insert that contacts the sintered plate (the lower surface on the seating surface side). When unevenness is formed on the seating surface of the cutting insert, an unstable clamping state will occur when the cutting insert is attached to the tool body.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Patent Document 2

Patent Document 3

Summary of the Invention

Problems to be Solved by the Invention

[0004] After sintering, a polishing process is required to remove the unevenness on the lower surface that becomes the seating surface of the cutting insert and flatten it, so the manufacturing is laborious and costly.

[0005] The present invention has been made in view of such circumstances, and when applied to a single-sided cutting insert, it is possible to achieve both cost reduction and ensuring flatness of the seating surface by eliminating the grinding process for the lower surface including the seating surface. The purpose is to provide a cutting insert and a cutting tool.

Means for Solving the Problems

[0006] In order to solve such problems and achieve the above object, the present invention proposes the following means. The cutting insert of the present invention is a plate-shaped cutting insert having a center line, and includes an upper surface constituting one surface facing each other in the axial direction along the center line, a lower surface constituting the other surface facing each other, a side surface connecting the upper surface and the lower surface in the axial direction, and a mounting hole penetrating in the axial direction. The side surface extends obliquely inward in the radial direction perpendicular to the center line as it extends from the upper surface to the lower surface in the axial direction. The lower surface has a seating surface having a plane perpendicular to the center line, and a pedestal having a protruding portion protruding in the axial direction from the outer peripheral edge of the seating surface in a direction away from the upper surface. The top of the protruding portion of the pedestal is perpendicular to the center line.

[0007] According to the configuration of the present embodiment, only the pedestal having the protruding portion protruding in the direction away from the upper surface from the seating surface among the lower surfaces of the cutting insert contacts the sintered plate, and the seating surface having a plane that abuts against the insert mounting seat does not contact the sintered plate. Therefore, no adhesion of the contact reaction inhibitor or sintering reaction marks are generated on the seating surface. As a result, the removal process of the contact reaction inhibitor deposit or sintering reaction marks on the seating surface, that is, the grinding process for the lower surface, becomes unnecessary, shortening the manufacturing process, and making it possible to achieve both cost reduction and ensuring flatness of the seating surface.

[0008] In the cutting insert of the present invention, the ridge line between the upper surface and the side surface may be inclined with respect to the plane perpendicular to the center line at the most protruding portion in the axial direction.

[0009] In a cutting insert that does not polish the side surface constituting the escape surface, in order to polish the lower surface that becomes the seating surface of the single-sided insert having cutting edges only on the ridge line of the upper surface and the side surface, it is necessary to hold the cutting insert by bringing the upper surface into contact with a jig. Since it is necessary to increase the contact area with the jig so that the main cutting edge is not damaged by the contact with the jig, for example, a portion parallel to the lower surface is required on the ridge line of the upper surface and the side surface that protrudes most in the center line direction of the upper surface as shown in FIG. 6 of Patent Document 1, and the shape of the second cutting edge 26 is determined by this protruding plane. On the other hand, by using the lower surface of the present invention, it becomes possible to design all the cutting edges of the cutting insert without being restricted by the polishing process. As a result, as a cutting tool in which the cutting insert is attached to the insert mounting seat of the tool body that rotates around the axis, it becomes possible to set an optimal axial rake angle and a radial rake angle in the radial direction.

[0010] In the cutting insert of the present invention, a flat surface may be provided at the top of the protruding portion of the pedestal.

[0011] Further, in the cutting insert of the present invention, the protruding portion of the pedestal may be provided in a ridge line shape.

[0012] According to this configuration, although it is disadvantageous from the viewpoint of the effect of suppressing deformation during sintering, the seating surface becomes wider, enabling stable contact with the insert mounting seat of the tool body.

[0013] Further, in the cutting insert of the present invention, the pedestal may be provided along the entire outer peripheral edge of the seating surface.

[0014] According to this configuration, during the sintering process when manufacturing the cutting insert, stable support is possible, and deformation during sintering can be suppressed.

[0015] In the cutting insert of the present invention, the pedestal may be provided along a part of the outer peripheral edge of the seating surface.

[0016] The cutting tool of the present invention includes a tool body that is rotatable in the tool rotation direction along the axis of the rotation axis and has an insert mounting seat to which a cutting insert is attached, and the insert mounting seat has a bottom surface capable of abutting on the seating surface of the cutting insert.

[0017] According to this configuration, when the cutting insert is attached to the tool body, the seating surface of the cutting insert abuts on the bottom surface of the insert mounting seat, so that the cutting insert is attached to the tool body. Since flat surfaces abut on each other, the cutting insert can be attached to the tool body without rattling, and a stable clamping state can be ensured.

Advantages of the Invention

[0018] According to the present invention, when applied to a single-sided cutting insert, by eliminating the grinding process for the lower surface including the seating surface, it is possible to provide a cutting insert and a cutting tool capable of achieving both cost reduction and ensuring the flatness of the seating surface.

Brief Description of the Drawings

[0019]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Figure 10

BEST MODE FOR CARRYING OUT THE INVENTION

[0020] Hereinafter, the cutting insert according to each embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a perspective view showing the cutting insert 1 according to the first embodiment of the present invention from the rake face side. FIG. 2 is a three-view drawing showing the cutting insert 1 according to the first embodiment of the present invention. FIG. 3 is a perspective view showing the cutting insert 1 according to the first embodiment of the present invention from the seating face side. The cutting insert 1 of the present embodiment is detachably attached to a tool body that rotates about an axis, and performs cutting on a workpiece made of a metal material such as steel.

[0021] (Cutting insert of the first embodiment) The cutting insert 1 of the present embodiment shown in FIGS. 1, 2, and 3 is formed of a hard material such as cemented carbide. The cutting insert 1 is formed in a plate shape that forms a polygon that is rotationally symmetric with respect to the center line O when viewed in a plan view from the center line O extending in the thickness direction. In the present embodiment, it has a rectangular shape in plan view, but is not limited to this shape.

[0022] In the following description, the direction along the center line O may be simply referred to as the thickness direction. Also, the direction orthogonal to the center line O may be simply referred to as the radial direction. Furthermore, the circumferential direction around the axis centered on the center line O may be simply referred to as the middle direction.

[0023] The cutting insert 1 has a rake face (upper face) 2 that forms one of the faces facing each other axially with respect to the center line O, a lower face 3 that forms the other face, a side face 4 that connects between the rake face 2 and the lower face 3, a cutting edge 5 formed on the intersection ridge line (ridge line) 7 between the rake face 2 and the side face 4, and a mounting hole 6 provided coaxially with the center line O. The mounting hole 6 is formed in the thickness direction of the cutting insert 1 and is a through hole that opens to both the rake face 2 and the lower face 3. The side face 4 extends obliquely inward in the radial direction perpendicular to the center line O as it goes from the rake face 2 in the axial direction toward the lower face 3. The lower face 3 has a size that is included inside the projection area of the rake face 2 in the thickness direction. As shown in FIG. 2, the intersection ridge line 7 between the rake face 2 and the side face 4 is inclined with respect to a plane perpendicular to the center line O at the most protruding portion in the axial direction.

[0024] FIG. 4 is a perspective view showing the configuration of the tip side of the tool body 10. The cutting insert 1 is attached to the tool body 10 shown in FIG. 4 and is used as a cutting tool together with the tool body 10. The cutting insert 1 is detachably attached to the insert mounting seat 11 of the tool body 10 that can rotate around the axis of the rotation axis CO by a clamping screw (not shown). The clamping screw is inserted into the mounting hole 6 of the cutting insert 1. The cutting insert 1 is restrained by the insert mounting seat 11 of the tool body 10 when it is attached to the tool body 10. The insert mounting seat 11 is a pedestal to which the cutting insert 1 is attached.

[0025] The insert mounting seat 11 has a bottom face 11a, a long side wall face 11b, and a short side wall face 11c. Further, the insert mounting seat 11 has a plurality of concave grooves (recesses) 11d, 11e around the bottom face 11a. The long side concave groove (recess) 11d is formed on both sides of the bottom face 11a in the radial direction, and one of them is formed between the bottom face 11a and the long side wall face 11b. The short side concave groove (recess) 11e is formed between the bottom face 11a and the short side wall face 11c. The long side concave groove 11d and the short side concave groove 11e are recessed in a direction opposite to the tool rotation direction T.

[0026] The bottom surface 11a is the surface facing the tool rotation direction T of the tool body 10. The bottom surface 11a is a surface facing the seating surface 3a of the cutting insert 1 to be described later and has an area substantially equal to that of the bottom surface 11a. A screw hole 13 into which a clamp screw 12 is inserted is formed substantially at the center of the bottom surface 11a.

[0027] As shown in FIG. 1, the rake face 2 of the cutting insert 1 has a flat surface 2a provided around the mounting hole 6 and an inclined surface 2b inclined from the cutting edge 5 toward the flat surface 2a. The flat surface 2a is a surface perpendicular to the center line O.

[0028] The lower surface 3 of the cutting insert 1 has a seating surface 3a that contacts and is constrained by the bottom surface 11a of the insert mounting seat 11, and a pedestal (protrusion) 3b that does not contact the bottom surface 11a of the insert mounting seat 11. Specifically, the lower surface 3 has a seating surface 3a formed of a plane perpendicular to the center line O, and a pedestal 3b formed of a protrusion that protrudes in the axial direction from the outer peripheral edge of the seating surface 3a away from the rake face 2 with respect to the seating surface 3a. The top 3bc of the pedestal 3b is perpendicular to the center line O.

[0029] The seating surface 3a is a plane orthogonal to the center line O. The seating surface 3a is parallel to the flat surface 2a on the rake face 2 side. The seating surface 3a is a surface that contacts the bottom surface 11a of the insert mounting seat 11. The seating surface 3a has an area substantially equal to or slightly smaller than that of the bottom surface 11a of the insert mounting seat 11. The mounting hole 6 opens substantially at the center of the seating surface 3a.

[0030] The pedestal 3b is formed over the entire circumferential direction (entire outer peripheral edge) of the seating surface 3a. Also, the pedestal 3b is formed on the outer peripheral edge of the seating surface 3a. The pedestal 3b protrudes axially outward from the seating surface 3a. That is, the pedestal 3b protrudes in the axial direction away from the rake face 2 with respect to the seating surface 3a. As a result, on the seating side of the cutting insert 1, a recess is formed that is recessed axially inward by the seating surface 3a and the pedestal 3b.

[0031] On the top 3bc of the pedestal 3b, a plane perpendicular to the center line O is provided, and there are no grinding marks on the entire plane. That is, in the present embodiment, the top 3bc of the pedestal 3b of the cutting insert 1 is sintered while contacting the sintered plate, and after sintering, no grinding process is performed.

[0032] In the present embodiment, it is provided on the entire outer peripheral edge of the seating surface 3a, but it is not limited to this, and it may be provided on a part of the outer peripheral edge. Also, in the present embodiment, the top 3bc of the pedestal 3b has a plane perpendicular to the center line O, but it is not limited to this, and it may have a surface other than a plane. For example, the top 3bc may have a curved surface forming a ridge line.

[0033] The height H in the axial direction of the pedestal 3b corresponds to the step amount between the seating surface 3a and the top 3bc of the pedestal 3b. The height H of the pedestal 3b is constant as a whole. The height H of the pedestal 3b is preferably in the range of, for example, 0.15 mm to 0.50 mm. Also, the range of 0.20 mm to 0.40 mm is more preferable, and in the present embodiment, it is 0.30 mm.

[0034] When the cutting insert 1 of the present embodiment is attached to the tool body 10 and the seating surface 3a of the cutting insert 1 is in contact with the bottom surface 11a of the insert mounting seat 11, the pedestal 3b enters the long-side concave groove 11d and the short-side concave groove 11e of the insert mounting seat 11, so it does not contact the bottom surface 11a of the insert mounting seat 11.

[0035] With such a configuration, the restraint strength of the cutting insert 1 with respect to the tool body 10 is mainly ensured by the surface contact between the bottom surface 11a and the seating surface 3a. Since it is restrained by the flat seating surface 3a and the bottom surface 11a, there is no play in the cutting insert 1, and a stable clamping state can be obtained with respect to the insert mounting seat 11 of the tool body 10.

[0036] Further, in the cutting insert 1, the portion (pedestal 3b) that contacts the sintered plate during sintering is provided separately from the seating surface 3a, and when the cutting insert 1 is attached to the tool body 10, the top 3bc of the pedestal 3b is shaped such that it does not contact the bottom surface 11a of the insert mounting seat 11 of the tool body 10. Therefore, grinding of the top 3bc of the pedestal 3b becomes unnecessary. Since the seating surface 3a does not contact the sintered plate, no sintering marks (minute irregularities) are generated, and flatness is ensured. For this reason, the grinding process that was conventionally performed on the seating side of the cutting insert 1 can be omitted. Thus, according to the cutting insert 1 of the present embodiment, both cost reduction and ensuring the flatness of the seating surface 3a can be achieved.

[0037] Also, in the present embodiment, the pedestal 3b is provided at the outer peripheral edge of the seating surface 3a. Thereby, the area of the seating surface 3a can be maximized on the seating side of the cutting insert 1, and the restraint strength against the tool body 10 can be increased. By providing the tool body 10 to which the cutting insert 1 of the present embodiment is attached, a cutting tool 100 with high machining accuracy can be obtained.

[0038] As described above, the first embodiment of the present invention has been described in detail with reference to the drawings. However, the specific configuration is not limited to this embodiment, and design changes and the like within the scope not departing from the gist of the present invention are also included.

[0039] For example, in the cutting insert 1 of the first embodiment described above, the pedestal 3b is formed across the entire outer peripheral edge of the seating surface 3a. However, the shape of the pedestal 3b of the cutting insert 1 is not limited to the shape described above. Some modification examples of the pedestal 3b will be described below. In the following description, for configurations common to those already described, the same reference numerals are given and redundant descriptions are omitted.

[0040] (Modification Example 1) FIG. 5 is a perspective view showing the seating side of the cutting insert 1A in Modification Example 1 of the first embodiment. As shown in Fig. 5, pedestal 3Ab is formed at each of the four corner portions 3f on the lower surface 3 side of the cutting insert 1A of Modification 1. The four pedestals 3Ab all have a shape that is symmetric with respect to the long side direction and the short side direction of the cutting insert 1. Each pedestal 3Ab has a first portion 3b1 extending along each long side 3g and a second portion 3b2 extending along the short side 3h, and has an L-shaped configuration in plan view. Between adjacent pedestals 3Ab in the circumferential direction, there is a seating surface 3a located on the rake face 2 side axially higher than the top 3bc of each pedestal 3Ab.

[0041] (Modification 2) Fig. 6 is a perspective view showing the seating side of the cutting insert 1B in Modification 2 of the first embodiment. As shown in Fig. 6, pedestals 3Bb are formed along a pair of long sides 3g of the seating surface 3a of the cutting insert 1B of Modification 2. Each pedestal 3Bb is formed over the entire length of the long side 3g.

[0042] (Modification 3) Fig. 7 is a perspective view showing the seating side of the cutting insert 1C in Modification 3 of the first embodiment. As shown in Fig. 7, pedestals 3Cb are formed along a pair of short sides 3h of the seating surface 3a of the cutting insert 1C of Modification 3. Each pedestal 3Cb is formed over the entire length of the short side 3h. (Modification 4) Fig. 8 is a perspective view showing the seating side of the cutting insert 1D in Modification 4 of the first embodiment. As shown in Fig. 8, a pedestal 3Db is formed on the outer peripheral edge of the seating surface 3a so as to include a pair of short sides 3h and four corner portions 3f. The pedestal 3Db extends over the entire length of each short side 3h and is provided along a part of the long side 3g from both ends of the short side 3h.

[0043] According to the above-described Modification Examples 1 to 4, it is possible to ensure the flatness of the seating surface 3a while maintaining the horizontal posture during firing by the pedestal 3b. Further, by providing the pedestal 3b in a predetermined range of at least the four corner portions 3f, the pair of long sides 3g, and the pair of short sides 3h among the outer peripheral edge of the seating surface 3a, it is possible to reduce the material cost. Furthermore, the top 3bc of each pedestal 3b in Modification Examples 1 to 4 has no grinding marks, and the manufacturing process can be simplified as in the first embodiment.

[0044] For example, the planar shape of the cutting insert is not limited to the shapes of the above-described embodiments. The planar shape of the cutting insert may be other than rectangular, and may be triangular, square, or circular.

[0045] (Modification Example 5) FIGS. 9 and 10 are perspective views showing the cutting insert 40 in Modification Example 5. For example, as shown in FIGS. 9 and 10, in the case of the cutting insert 40 having a circular shape in plan view, it is preferable to form a lower surface 43 having a flat seating surface 43a and a pedestal 43b formed on the entire outer peripheral edge of the seating surface 43a on the seating side. The top 43bc of the pedestal 43b has no grinding marks and protrudes axially outward from the seating surface 43a.

[0046] In addition, in each of the above-described embodiments and modification examples, the pedestal 3b is provided on the outer peripheral edge of the seating surface 3a, but the present invention is not limited to this. For example, the pedestal 3b may be provided inside the seating surface 3a. Further, the pedestal 3b may be provided on the outer peripheral edge (outline) of the lower surface 3 instead of on the outer peripheral edge of the seating surface 3a.

[0047] In addition, in each of the above-described embodiments and modification examples, one seating surface 3a is provided around the mounting hole 6 of the cutting insert, but the present invention is not limited to this. For example, a pair of seating surfaces 3a may be provided on both sides in the radial direction of the mounting hole 6, or a plurality of seating surfaces 3a may be provided around the mounting hole 6. Each seating surface 3a may be a plane perpendicular to the center line O.

Explanation of Reference Numerals

[0048] 1(1A, 1B, 1C, 1D) … Cutting insert of the first embodiment (Modifications 1 to 4) 2 … Rake face 3 … Lower surface of the first embodiment 3a … Seating surface of the cutting insert of the first embodiment 3b(3Ab, 3Bb, 3Cb, 43b) … Base of the first embodiment (Modifications 1 to 4) 3bc … Top of the base of the first embodiment 3f … Corner part 3g … Long side 3h … Short side 4 … Side surface 6 … Mounting hole 7 … Ridge line 10 … Tool body 11 … Insert mounting seat 11a, 11b, 11c … Bottom surface, long side wall surface, short side wall surface of the insert mounting seat 40 … Cutting insert of Modification 5 43 … Seating surface of Modification 5 43a … Seating surface of Modification 5 43b … Base of Modification 5 43bc … Top of the base of Modification 5 100 … Cutting tool

Claims

1. A plate-shaped cutting insert having a center line, an upper surface that constitutes one surface facing each other in the axial direction along the center line, a lower surface that constitutes the other surface facing each other, a side surface that connects the upper surface and the lower surface in the axial direction, and a mounting hole that penetrates in the axial direction, and is a single-sided cutting insert having a cutting edge only on the intersection ridge line between the upper surface and the side surface, the side surface inclines and extends inward in the radial direction perpendicular to the center line as it goes from the upper surface to the lower surface in the axial direction, the lower surface has a seating surface having a plane perpendicular to the center line and a pedestal having a protruding portion protruding in the axial direction away from the upper surface than the seating surface at the outer peripheral edge of the seating surface, a cutting insert, wherein the top of the protruding portion of the pedestal is perpendicular to the center line.

2. The ridge line between the upper surface and the side surface is inclined with respect to the plane perpendicular to the center line at the most protruding portion in the axial direction, The cutting insert according to Claim 1.

3. The cutting insert according to Claim 1 or 2, wherein a plane is provided at the top of the protruding portion of the pedestal.

4. The top of the protruding portion of the pedestal is in the shape of a ridge line, The cutting insert according to any one of Claims 1 to 3.

5. The cutting insert according to any one of Claims 1 to 4, wherein the pedestal is provided on the entire outer peripheral edge of the seating surface.

6. The cutting insert according to any one of Claims 1 to 4, wherein the pedestal is provided along a part of the outer peripheral edge of the seating surface.

7. A cutting insert according to any one of Claims 1 to 6, and a tool body having an insert mounting seat that is rotatable in the tool rotation direction along the axis of the rotation axis and to which the cutting insert is mounted, wherein the insert mounting seat has a bottom surface capable of abutting against the seating surface of the cutting insert, a cutting tool.

Images