Cutting insert and cutting tool

Abstract

To provide a cutting insert which can be reduced in diameter while sufficiently securing strength and yet can feed a coolant into a cut portion, and a cutting tool provided with the same.SOLUTION: A cutting insert 50 attached to a body 10 in drilling a hole in a material to be cut, comprises: a cutting blade 53 that cuts the material to be cut; at least two guide parts 54 and 55 that slidably contact with an inner surface of the drilled hole of the material to be cut formed by the hole drilling; and a fluid groove 56 that is formed between the guide parts 54 and 55, and dents inward more than a circumscribed circle R circumscribed with the guide parts 54 and 55 and an end part at an outer periphery side of the cutting blade 53 in a front view.SELECTED DRAWING: Figure 6

Description

[Technical Field]

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

[0002] Patent Document 1 shows a cutting tool for drilling in which a cutting insert is attached to an insert mounting seat on a body. Patent Document 2 discloses a cutting tool in which a groove for supplying cutting oil is provided on the outer periphery of the body, and Patent Document 3 discloses a cutting tool equipped with a cutting insert having a guide portion that slides against the inner periphery of a drilled hole to guide the insert. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2006-192553 [Patent Document 2] Patent No. 6849136 [Patent Document 3] International Publication No. 2021 / 214747 Summary of the Invention [Problem to be solved by the invention]

[0004] The cutting tool described in Patent Document 1 fixes the cutting insert and two guide pads to the body with screws. As such, this cutting tool has many components, making it difficult to reduce its diameter. Therefore, even if the components are accommodated in a limited space, the cutting insert and body may not be thick enough, resulting in reduced strength and making highly efficient machining difficult. Even if the cutting insert can be made smaller, it is difficult to provide a flow path for supplying coolant to the cutting area, as in the cutting tool described in Patent Document 2. Patent Document 3 also includes a recess formed in the cutting insert, but this recess is a portion into which the tip of the body is inserted to fix the insert to the body, making it difficult to use the recess as a flow path for supplying coolant.

[0005] The present invention has been made in consideration of the above circumstances, and aims to provide a cutting insert and a cutting tool equipped with the same that can reduce the diameter of the tool while ensuring sufficient strength and can efficiently deliver coolant to the cutting location. [Means for solving the problem]

[0006] A cutting insert according to one embodiment of the present invention is a cutting insert that is attached to a body when drilling a hole in a workpiece, and has a cutting edge that cuts the workpiece, at least two guide portions that slide against the inner surface of the drilled hole in the workpiece formed by drilling, and a fluid groove that is provided between the guide portions and is recessed inward from a circumscribing circle that circumscribes the outer peripheral ends of the guide portions and cutting edges when viewed from the front.

[0007] The cutting insert with the above structure has two guide sections that slide against the inner surface of the drilled hole, which consolidates the function of the guide pads that are attached to the holder with screws into the cutting insert, reducing the number of components. This allows the tool diameter to be reduced while maintaining the thickness of the cutting insert and ensuring sufficient strength. In addition, coolant can be sent to the cutting point of the workpiece material by the cutting edge through the fluid groove.

[0008] In a front view, the distance between the center of the circumscribing circle and the closest point of the fluid groove to the center of the circumscribing circle may be greater than ¼ of the diameter of the circumscribing circle.

[0009] The bottom of the fluid groove may be formed in an arc shape when viewed from the front.

[0010] The bottom of the fluid groove may be formed in a linear shape when viewed from the front.

[0011] The vehicle body may have a fastening portion for fastening to the vehicle body by a fastening part.

[0012] The contact surface may be located forward of the fastening portion and below the bottom surface.

[0013] The contact surface may be an inclined surface that is inclined relative to the bottom surface.

[0014] The cutting edge may have an outer cutting edge and a central cutting edge that protrudes further toward the tip side than the outer cutting edge, and a step may be formed between the outer cutting edge and the central cutting edge.

[0015] A cutting tool according to one aspect of the present invention includes the cutting insert described above and a body to which the cutting insert is attached.

[0016] The cutting tool may be a hole drilling tool for drilling holes in a workpiece.

[0017] The cutting insert of the cutting tool may be attached to the body with the center of the circumscribing circle aligned with the central axis of rotation of the body. [Effects of the Invention]

[0018] According to the present invention, a cutting insert and a cutting tool equipped with the same are provided that can reduce the diameter of the tool while ensuring sufficient strength and can efficiently deliver coolant to the cutting location. [Brief explanation of the drawings]

[0019] [Figure 1] FIG. 1 is a perspective view of a cutting tool according to the present embodiment. [Figure 2] FIG. 2 is an exploded perspective view of the cutting tool according to this embodiment. [Figure 3] FIG. 3 is a plan view of the cutting tool. [Figure 4] FIG. 4 is a right side view of the cutting tool. [Figure 5] FIG. 5 is a bottom view of the cutting tool. [Figure 6] FIG. 6 is a front view of the cutting tool. [Figure 7] FIG. 7 is a perspective view of the body. [Figure 8] FIG. 8 is a perspective view of the body as viewed from the bottom side. [Figure 9] FIG. 9 is a plan view of the body. [Figure 10] FIG. 10 is a cross-sectional view taken along line XX in FIG. [Figure 11] FIG. 11 is a cross-sectional view taken along line XI-XI in FIG. [Figure 12] FIG. 12 is a perspective view of the cutting insert. [Figure 13] FIG. 13 is a plan view of the cutting insert. [Figure 14] FIG. 14 is a right side view of the cutting insert. [Figure 15] FIG. 15 is a bottom view of the cutting insert. [Figure 16] FIG. 16 is a front view of the cutting insert. [Figure 17] FIG. 17 is a cross-sectional view taken along line XVII-XVII in FIG. [Figure 18] FIG. 18 is a cross-sectional view taken along line XVIII-XVIII in FIG. DETAILED DESCRIPTION OF THE INVENTION

[0020] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the cutting insert and cutting tool according to the present invention will be described in detail below with reference to the drawings.

[0021] 1 to 6, a cutting tool 100 according to this embodiment has a body 10 and a cutting insert 50. This cutting tool 100 has the cutting insert 50 attached to the tip of the body 10. The cutting tool 100 is rotated about a central rotation axis AX1, and performs drilling on a workpiece using the cutting insert 50 at the tip of the body 10, and can also be used during turning to cut a rotating workpiece.

[0022] As shown in Figures 7 to 11, the body 10 has an insert pocket 11. The insert pocket 11 functions as an insert mounting seat in which the cutting insert 50 is mounted, and is formed at the tip of the body 10. The cutting insert 50 is attached to the insert pocket 11.

[0023] The insert pocket 11 has a lower jaw portion 13 having a seat surface 12 and an upper jaw portion 15 having an abutment surface 14, and these lower jaw portion 13 and upper jaw portion 15 extend toward the tip side of the body 10.

[0024] The lower jaw 13 and the upper jaw 15 are disposed with a gap between them, and a receiving groove 16 into which the cutting insert 50 is inserted is defined between the lower jaw 13 and the upper jaw 15. The receiving groove 16 has a groove width W1 on the front end side of the body 10 that is narrower than a groove width W2 on the rear end side (see FIG. 10).

[0025] The upper jaw 15 constituting the insert pocket 11 has a smaller width in a plan view than the lower jaw 13 and is disposed opposite the lower jaw 13 on one side in the width direction (see FIG. 9 ). In this embodiment, the plan view of the body 10 refers to a view from a direction perpendicular to the front view of the body 10, as viewed from the tip end of the body 10 with the central axis of rotation AX1 as the reference, in which the cutting edge 53 is oriented substantially horizontally as shown in FIG. 6 . A threaded hole 18 is formed in the bearing surface 12 of the lower jaw 13, and a screw 75, which is a fastening component for fastening the cutting insert 50, is threaded into the threaded hole 18 (see FIG. 1 ). The threaded hole 18 is formed in a position of the lower jaw 13 that is not opposed to the upper jaw 15. Thus, the insert pocket 11 of the body 10 includes the bearing surface 12 of the lower jaw 13 having the threaded hole 18 and the abutment surface 14 of the upper jaw 15. The upper jaw portion 15 is formed with a recess 19 for avoiding interference with the screw 75 that is screwed into the screw hole 18 of the lower jaw portion 13 .

[0026] In a front view of the body 10, the screw hole 18 has a central axis CL1 that is inclined with respect to a perpendicular line PL1 to the seating surface 12 (see FIG. 11). In addition, in a side view of the body 10, the central axis CL1 of the screw hole 18 is inclined with respect to the perpendicular line PL1 to the seating surface 12 toward the rear end in a direction away from the abutment surface 14 (see FIG. 10). By inclining the central axis CL1 of the screw hole 18 with respect to the perpendicular line PL1 to the seating surface 12 in this manner, it is possible to increase the number of threads in the screw hole 18. Particularly in this embodiment, if the central axis CL1 of the screw hole is inclined with respect to the perpendicular line PL1 so as to approach from one side 10a to the other side 10b of the body 10 in a front view of the body 10, it is possible to further increase the number of threads in the screw hole 18.

[0027] The body 10 has a front restraint surface 21 and a rear restraint surface 22. The front restraint surface 21 is provided on the front side of the body 10 in the insert pocket 11, and the rear restraint surface 22 is provided on the rear side of the body 10 in the insert pocket 11. The front restraint surface 21 is formed at the front end of the lower jaw 13 that constitutes the insert pocket 11, and the rear restraint surface 22 is formed on the back side of the insert pocket 11. The front restraint surface 21 and the rear restraint surface 22 are formed along the lateral width direction of the insert pocket 11.

[0028] The front restraint surface 21 and the rear restraint surface 22 are non-parallel to each other in the plan view of FIG. 9. Specifically, the front restraint surface 21 is gradually inclined toward the front end from one side 10a to the other side 10b of the body 10, and the rear restraint surface 22 is gradually inclined toward the rear end from one side 10a to the other side 10b of the body 10. As a result, the front restraint surface 21 and the rear restraint surface 22 are arranged in a V-shape so as to move away from each other from one side 10a to the other side 10b in the plan view of FIG. 9. Furthermore, the front restraint surface 21 is an inclined surface that gradually inclins toward the front end of the lower jaw 13 from the bearing surface 12 of the lower jaw 13 toward the bottom of the lower jaw 13. Note that a relief groove 23 is formed between the rear restraint surface 22 and the bearing surface 12 to avoid interference with the cutting insert 50.

[0029] The body 10 has two grooves 31 and 32 (see FIGS. 8 and 9). One groove 31 is formed on the lower jaw 13 on the side opposite the upper jaw 15, and the other groove 32 is formed on the upper jaw 15 on the side opposite the lower jaw 13. These grooves 31 and 32 are formed along the central axis AX1 of rotation of the body 10. The body 10 also has two outlets 33 and 34. These outlets 33 and 34 are coolant outlets, and coolant fed through a supply path (not shown) formed inside the body 10 is discharged from the outlets 33 and 34. One groove 31 is connected near its rear end to one outlet 33, and the other groove 32 is connected to the other outlet 34 at its rear end. Coolant is a fluid supplied from the machine tool during machining for the purposes of removing chips and cooling, lubricating, and preventing rust of the tool and workpiece.

[0030] The body 10 also has a discharge groove 35 (see FIG. 7). The discharge groove 35 is a concave groove portion that discharges chips generated during cutting, and is formed from the front end side of the body 10 toward the rear end side of the body 10.

[0031] 12 to 16, the cutting insert 50 is fitted into the insert pocket 11 of the body 10 with the rear portion 52 facing the body 10 (see FIG. 2). The cutting insert 50 is made of various materials such as cemented carbide, cermet, ceramics, ultra-high pressure sintered compact, or diamond.

[0032] The cutting insert 50 has a cutting edge 53, two guide portions 54, 55, and a fluid groove 56. The cutting edge 53, the guide portions 54, 55, and the fluid groove 56 are provided on the front portion 51 of the cutting insert 50. The cutting insert 50 may have a plurality of cutting edges 53. Furthermore, the cutting insert 50 is only required to have at least two guide portions 54, 55, and therefore may have three or more guide portions.

[0033] When the cutting insert 50 is attached to the body 10, the cutting edge 53 cuts the workpiece by rotating relative to the workpiece. The cutting edge 53 has a central cutting edge 61 and a peripheral cutting edge 62. The central cutting edge 61 mainly cuts the center side of the bottom of the drilled hole, and the peripheral cutting edge 62 mainly cuts the outer side of the bottom of the drilled hole. The central cutting edge 61 protrudes further toward the tip than the peripheral cutting edge 62, thereby forming a step 63 between the central cutting edge 61 and the peripheral cutting edge 62. By providing this step 63, chips are divided vertically along the direction of extension compared to when there is no step 63, resulting in more compact chip shapes. This makes it less likely that the generated chips will clog during discharge.

[0034] The guide portions 54, 55 guide the cutting tool 100 by sliding against the inner surface of a machined hole in the workpiece when cutting the workpiece. The guide portion 54 is provided on the side opposite the upper surface 57 of the cutting insert 50, and the guide portion 55 is provided on the side substantially opposite the outer circumferential end of the cutting edge 53 (see FIG. 16). The cutting insert 50 has a substantially semicircular shape in a front view, and the two guide portions 54, 55 are formed in an arc shape in a front view (see FIG. 16). Here, when cutting the workpiece, a cutting force F is generated at the cutting edge 53 of the cutting insert 50. If the center of a circumscribed circle R that circumscribes the guide portions 54, 55 and the outer circumferential end of the cutting edge 53 in a front view is O, in this example, for example, the cutting force F is generated radially outward from a position closer to the center O of the circumscribed circle R than the center of the cutting edge 53 in a front view (see FIG. 16). In the cutting insert 50 of this example, the guide portions 54, 55 are arranged so as to sandwich the generated cutting force F. In other words, the guide portions 54, 55 are arranged so that even if the direction of the cutting force F changes, the cutting force F will be contained between the two guide portions 54, 55. Therefore, even if the direction of the cutting force F changes, the cutting force F can be received by the two guide portions 54, 55, allowing for more stable machining.

[0035] The fluid groove 56 is provided between the two guide portions 54, 55. The fluid groove 56 is formed at a position continuous with one of the groove portions 31 of the body 10 when the cutting insert 50 is attached to the body 10. The fluid groove 56 is recessed in an arc shape in a front view. The bottom of the fluid groove 56 is recessed inward from the circumscribing circle R in a front view (see FIG. 6). In the fluid groove 56, the distance L between the center O of the circumscribing circle R and the nearest point P from the center O of the circumscribing circle R in a front view is greater than ¼ of the diameter D of the circumscribing circle R (see FIG. 6). Note that the shape of the bottom of the fluid groove 56 in a front view of the body 10 is not limited to an arc shape and may be formed in a linear shape. When formed in an arc shape, the flow path cross-sectional area of ​​the fluid groove 56 can be increased while ensuring the area of ​​the guide portion 54. Furthermore, when the fluid groove 56 is formed in a linear shape, the distance L from the center O of the circumscribing circle R to the nearest point P can be increased, so that the fluid groove 56 can be formed while maintaining high strength of the cutting insert 50. The shape of the fluid groove 56 can be appropriately selected depending on the desired effect.

[0036] The rear portion 52 of the cutting insert 50 is formed in a flat plate shape with a smooth bottom surface 71. When the cutting insert 50 is attached to the insert pocket 11 of the body 10, the bottom surface 71 of the rear portion 52 abuts against the seat surface 12.

[0037] The cutting insert 50 has a through hole 73. The through hole 73 is a fastening portion for fixing the cutting insert 50 to the insert pocket 11 of the body 10, and is formed in the rear portion 52 of the cutting insert 50. The through hole 73 is a trumpet-shaped tapered hole with a larger diameter on the upper side. A screw 75, which is a fastening part for fastening the cutting insert 50 to the body 10, is inserted into the through hole 73 from above. A head 77 of the screw 75 abuts against the sloping surface of the trumpet-shaped tapered hole in the larger diameter portion of the through hole 73 (see FIG. 1).

[0038] In a front view of the cutting insert 50, the through hole 73 has a central axis CL2 inclined with respect to a perpendicular line PL2 to the bottom surface 71 (see FIG. 16). In addition, in a side view of the cutting insert 50, the central axis CL2 of the through hole 73 inclined rearward from the upper surface 57 to the bottom surface 71 with respect to the perpendicular line PL2 to the bottom surface 71.

[0039] The cutting insert 50 has a front abutment surface 81 and a rear abutment surface 82 (see FIG. 15 ). The front abutment surface 81 is provided on the front side of the through hole 73, and the rear abutment surface 82 is provided on the rear side of the through hole 73. These front abutment surface 81 and rear abutment surface 82 are surfaces facing rearward. The front abutment surface 81 is provided below the bottom surface 71 that abuts against the seat surface 12 of the insert pocket 11, and is an inclined surface that slopes downward toward the front side. Note that the front abutment surface 81 does not necessarily have to be an inclined surface; for example, it may be a vertical surface. On the other hand, if the front abutment surface 81 is an inclined surface that forms an obtuse angle with the bottom surface 71, it can more effectively receive the cutting force F generated downward of the cutting insert 50 during machining. The rear abutment surface 82 is composed of two divided abutment surfaces 82a and 82b, divided left and right. Due to the presence of a recess between the divided abutment surface 82a and the divided abutment surface 82b, when the cutting insert 50 is attached to the body 10, the cutting insert 50 always abuts against the rear restraint surface 22 of the insert pocket 11 outside the rear abutment surface 82, and the cutting insert 50 can be fixed without any rattle.

[0040] The front abutment surface 81 and the rear abutment surface 82 are not parallel to each other in the plan view of Fig. 15. Specifically, the front abutment surface 81 is gradually inclined forward from one side 50a to the other side 50b of the cutting insert 50, and the rear abutment surface 82 is gradually inclined rearward from one side 50a to the other side 50b of the cutting insert 50. As a result, the front abutment surface 81 and the rear abutment surface 82 are arranged in a V-shape so as to move away from each other from the one side 10a to the other side 10b in the plan view of Fig. 15 (see Fig. 15). Here, the cutting insert 50 receives a cutting force along the rear constraint surface 22 in the direction of the other side 10b of the body 10 during cutting. At this time, the front restraint surface 21 of the body 10, which abuts the front abutment surface 81 of the cutting insert 50, is inclined in the opposite direction to the rear restraint surface 22, so that the cutting insert 50 that tries to move toward one side 10b of the body 10 can be held down.

[0041] 17 and 18, when the cutting insert 50 is placed in the insert pocket 11 of the body 10, the central axis CL2 of the through hole 73 is shifted with respect to the central axis CL1 of the screw hole 18 formed in the lower jaw portion 13 that constitutes the insert pocket 11. Specifically, the central axis CL2 of the through hole 73 is shifted toward the tip side and the other side 10b of the body 10 with respect to the central axis CL1 of the screw hole 18.

[0042] In this way, the central axis CL2 of the through hole 73 of the cutting insert 50 is misaligned with the central axis CL1 of the screw hole 18 of the insert pocket 11, so that when the cutting insert 50 is assembled to the body 10, the front abutment surface 81 of the cutting insert 50 abuts against the front restraint surface 21 of the insert pocket 11, and then the cutting insert 50 is pulled rearward of the body 10 while sliding on the front restraint surface 21 toward one side 10a of the body 10. This makes it easier to abut the cutting insert 50 against both the front restraint surface 21 and the rear restraint surface 22.

[0043] Next, the mounting of the cutting insert 50 to the body 10 will be described. To attach the cutting insert 50 to the body 10, the cutting insert 50 is brought close to the insert pocket 11 of the body 10 from its tip side. At this time, the rear part 52 of the cutting insert 50 is directed toward the body 10, and the vertical position of the cutting insert 50 is aligned with the body 10 (see FIG. 2).

[0044] The cutting insert 50 is then inserted into the accommodation groove 16 formed in the insert pocket 11 of the body 10 and accommodated between the lower jaw 13 and the upper jaw 15. The cutting insert 50 is then elastically sandwiched and held in the accommodation groove 16, in which the groove width W1 at the front end of the body 10 is narrower than the groove width W2 at the rear end. Note that this holding state is merely a temporary fixation state, and the holding force at this time is not sufficient to withstand the cutting force during cutting.

[0045] Next, a screw 75 is inserted into the through hole 73 of the cutting insert 50, and this screw 75 is screwed into the threaded hole 18 of the lower jaw portion 13. At this time, since the cutting insert 50 is held in the receiving groove portion 16 of the insert pocket 11, the screw 75 can be fastened without gripping the cutting insert 50.

[0046] In this way, when the screw 75 inserted into the through hole 73 of the cutting insert 50 is screwed into the threaded hole 18 of the lower jaw portion 13, the cutting insert 50 is fixed to the lower jaw portion 13 in a state of close contact with the seat surface 12 of the lower jaw portion 13 and the abutment surface 14 of the upper jaw portion 15, and is attached to the insert pocket 11.

[0047] Here, the central axis CL2 of the through hole 73 of the cutting insert 50 is shifted toward the tip side and the other side 10b of the body 10 with respect to the central axis CL1 of the screw hole 18. Therefore, as described above, after the front abutment surface 81 abuts against the front restraint surface 21 of the insert pocket 11, the cutting insert 50 is pulled toward the rear of the body 10 while sliding on the front restraint surface 21 toward the one side 10a of the body 10. As a result, the cutting insert 50 is attached to the insert pocket 11 with the front abutment surface 81 and the rear abutment surface 82 abutting against the front restraint surface 21 and the rear restraint surface 22 of the insert pocket 11, respectively. Therefore, the cutting insert 50 is fixed in the insert pocket 11 with high holding force and without rattle. The cutting insert 50 is attached to the body 10 with the center of the circumscribed circle R aligned with the rotational center axis AX1 of the body 10.

[0048] Furthermore, when the cutting insert 50 is attached to the insert pocket 11 , the fluid groove 56 provided between the guide portions 54 and 55 of the cutting insert 50 is communicated with the groove portion 31 of the body 10 .

[0049] In the cutting tool 100 in which the cutting insert 50 is attached to the insert pocket 11 of the body 10 in this manner, the coolant discharged from the discharge port 33 passes through the groove 31 and the fluid groove 56 and is sent to the cutting point. In addition, the coolant discharged from the discharge port 34 passes through the groove 32 and is sent to the cutting point. Therefore, the coolant effectively cools the cutting insert 50 and discharges chips.

[0050] In this cutting tool 100, when a hole is drilled in a workpiece, the rotational force generated in the cutting insert 50 is received by the seat surface 12 and the abutment surface 14 that constitute the insert pocket 11 of the body 10. In addition, the rearward pressing force of the cutting insert 50 generated by pushing the cutting tool 100 is received by the front constraint surface 21 and the rear constraint surface 22 of the insert pocket 11 of the body 10, with which the front abutment surface 81 and the rear abutment surface 82 abut.

[0051] As described above, in this embodiment, the cutting insert 50 includes two guide portions 54, 55 that slide against the inner surface of the drilled hole. This allows the cutting insert 50 to function as a guide pad that is attached to a holder by a screw, thereby reducing the number of components. This allows the tool diameter to be reduced while maintaining the thickness of the cutting insert 50 and ensuring sufficient strength. In addition, coolant can be sent through the fluid groove 56 to the cutting point of the workpiece material being cut by the cutting edge 53.

[0052] Furthermore, the distance L between the center O of the circumscribing circle R and the closest point P of the fluid groove 56 to the center O of the circumscribing circle R is set to be greater than ¼ of the diameter D of the circumscribing circle R. Therefore, by providing the fluid groove 56, it is possible to maintain sufficient strength while sending coolant to the cutting point of the workpiece.

[0053] Furthermore, the rear portion 52 has a through hole 73 through which a screw 75 is inserted, so that the screw 75 can be easily inserted into the through hole 73 and fastened to the body 10 for fixation.

[0054] Furthermore, by abutting the front abutment surface 81, which is forward of the through hole 73 and below the bottom surface 71, against the front restraint surface 21 of the body 10, the body 10 can withstand the cutting force F received when the cutting edge 53 cuts the workpiece, thereby alleviating the stress on the screw 75 applied during cutting.

[0055] The present disclosure is not limited to the above specific examples, and designs that are appropriately modified by a person skilled in the art from these specific examples are also included within the scope of the present disclosure as long as they have the features of the present disclosure. The elements of the above specific examples, as well as their arrangement, conditions, shape, etc., are not limited to those exemplified and can be modified as appropriate. The elements of the above specific examples can be combined as appropriate as long as no technical contradictions arise. [Explanation of symbols]

[0056] 10 Body 50 cutting inserts 53 Cutting edge 54,55 Guide section 56 Fluid groove 61 Center blade 62 Peripheral blade 63 Steps 71 bottom 73 Through hole (fastening part) 75 Screws (fasteners) 100 cutting tools AX1 Rotational axis D: Diameter of the circumscribed circle L distance O Center of the circumscribed circle P nearest neighbors R circumscribed circle

Claims

1. A cutting insert that is attached to a body when drilling a hole in a workpiece, a cutting edge for cutting the workpiece; At least two guide portions that come into sliding contact with the inner surface of a machined hole formed in the workpiece by hole machining; a fluid groove provided between the guide portions and recessed inward from a circumscribed circle circumscribing the guide portions and the outer peripheral end of the cutting edge in a front view; having Cutting insert.

2. In a front view, the distance between the center of the circumscribing circle and a point on the fluid groove that is closest to the center of the circumscribing circle is greater than ¼ of the diameter of the circumscribing circle. The cutting insert according to claim 1 .

3. When viewed from the front, the bottom of the fluid groove is formed in an arc shape. The cutting insert according to claim 1 .

4. When viewed from the front, the bottom of the fluid groove is formed in a linear shape. The cutting insert according to claim 1 .

5. a fastening portion for fastening to the body by a fastening part; The cutting insert according to claim 1 .

6. The fastening portion has a contact surface on the front side and on the bottom surface on the lower side. The cutting insert according to claim 5 .

7. The abutment surface is an inclined surface inclined with respect to the bottom surface. The cutting insert according to claim 6 .

8. The cutting edge has an outer cutting edge and a central cutting edge that protrudes further toward the tip side than the outer cutting edge, and a step is formed between the outer cutting edge and the central cutting edge. The cutting insert according to claim 1 .

9. The cutting insert according to any one of claims 1 to 8, a body to which the cutting insert is attached; Equipped with cutting tools.

10. The cutting insert is attached to the body in a state where the center of the circumscribing circle is aligned with the rotation central axis of the body. The cutting tool according to claim 9.

Images