Cutting insert and cutting tool

Abstract

The invention provides a cutting insert and a cutting tool including the cutting insert, which can ensure enough strength of the cutting insert itself, can realize miniaturization of the tool, and can perform stable cutting. A cutting insert (50) attached to a main body (10) when drilling a material to be cut is provided with a cutting edge (53), at least two guides (54, 55), and a through-hole (73). The cutting blade (53) is used for cutting a material to be cut, the at least two guide parts (54, 55) are in sliding contact with the inner surface of a machining hole of the material to be cut formed by drilling, and the through hole (73) is used for fixing the cutting insert (50) to the main body (10). The cutting insert (50) has a front contact surface (81) and a rear contact surface (82) facing rearward, respectively, on the front side and the rear side with respect to the through-hole (73).

Description

Technical Field

[0001] This invention relates to a cutting blade and a cutting tool. Background Technology

[0002] Patent Document 1 discloses a cutting tool for drilling, wherein a cutting blade is mounted on a blade mounting seat of the main body. Furthermore, Patent Document 2 discloses a cutting tool equipped with a cutting blade having a guide portion that slides in contact with the inner circumferential surface of the cutting hole for guidance.

[0003] Existing technical documents

[0004] Patent documents

[0005] Patent Document 1: Japanese Patent Application Publication No. 2006-192553

[0006] Patent Document 2: International Publication No. 2021-214747

[0007] Technical issues

[0008] However, the cutting tool described in Patent Document 1 uses screws to fix the cutting insert and two guide blocks to the main body. As a result, due to the large number of components, miniaturization is difficult to achieve in this cutting tool. Therefore, even if the components are housed within a limited space, the thickness of the cutting insert or the main body cannot be adequately ensured, leading to reduced strength and hindering efficient machining. Furthermore, in Patent Document 2, the cutting insert has a guide portion, but in this cutting tool, since the abutment surface facing axially rearward can only be closer to the rear than the fastening portion, it is easy to apply a large load to the screws of the fastening portion; there is room for further improvement in this respect.

[0009] The present invention was made in view of the above circumstances, and its object is to provide a cutting insert and a cutting tool including the cutting insert, which can ensure sufficient strength, achieve tool miniaturization, and perform stable cutting. Summary of the Invention

[0010] One embodiment of the present invention provides a cutting insert, which is mounted on a main body for drilling a workpiece, and includes:

[0011] Cutting edge, used to cut the material being cut;

[0012] At least two guide portions slide in contact with the inner surface of the machining hole formed by drilling in the workpiece;

[0013] The fastening part is used to fix the cutting blade to the body, wherein,

[0014] The cutting blade has at least one rearward abutment surface on both the front and rear sides relative to the fastening part.

[0015] The cutting insert with the above-described structure includes two guide portions that slide in contact with the inner surface of the machined hole, eliminating the need for guide blocks that are screwed onto the retainer, thereby reducing the number of components. This maintains the thickness of the cutting insert to ensure sufficient strength while also enabling tool miniaturization. Furthermore, the cutting insert has at least one rearward-facing abutment surface on both the front and rear sides relative to the fastener. Therefore, by abutting these abutment surfaces against the body, the body side can bear the forces generated during cutting. This reduces the load on the fastener, resulting in stable cutting. Additionally, by abutting the abutment surfaces against the body, positioning relative to the body is easily achieved.

[0016] In a front view, the cutting blade may appear to be roughly semi-circular.

[0017] In the bottom view, the front abutment surface and the rear abutment surface may not be parallel to each other.

[0018] In the bottom view, from one side to the other, the front abutment surface and the rear abutment surface can move away from each other.

[0019] The rear abutment surface can be composed of at least two segmented abutment surfaces.

[0020] An embodiment of the present invention provides a cutting tool including the above-mentioned cutting blade and a body on which the cutting blade is mounted.

[0021] In the front view, the cutting insert is mounted on the main body with the center of its circumscribed circle coinciding with the rotation center axis of the main body, and the circumscribed circle is externally connected to the outer peripheral end of the guide and the cutting edge.

[0022] According to the present invention, a cutting insert and a cutting tool including the cutting insert are provided, which can ensure sufficient strength, achieve tool miniaturization, and perform stable cutting. Attached Figure Description

[0023] Figure 1 This is a perspective view of the cutting tool provided in this embodiment.

[0024] Figure 2 This is an exploded perspective view of the cutting tool provided in this embodiment.

[0025] Figure 3 This is a top view of the cutting tool.

[0026] Figure 4 This is a right-side view of the cutting tool.

[0027] Figure 5 This is a bottom view of the cutting tool.

[0028] Figure 6 This is the front view of the cutting tool.

[0029] Figure 7 It is a three-dimensional image of the main body.

[0030] Figure 8 This is a three-dimensional view of the subject as seen from its bottom side.

[0031] Figure 9 This is a top view of the main body.

[0032] Figure 10 yes Figure 9 Cross-sectional view of the main body along XX.

[0033] Figure 11 yes Figure 9 Cross-sectional view of the main body along XI-XI.

[0034] Figure 12 It is a 3D view of the cutting blade.

[0035] Figure 13 This is a top view of the cutting blade.

[0036] Figure 14 This is a right-side view of the cutting blade.

[0037] Figure 15 This is a bottom view of the cutting blade.

[0038] Figure 16 This is the front view of the cutting blade.

[0039] Figure 17 yes Figure 3 Cross-sectional view of the cutting tool along XVII-XVII.

[0040] Figure 18 yes Figure 3 Cross-sectional view of the cutting tool along XVIII-XVIII.

[0041] Explanation of main component symbols

[0042] Main body 10

[0043] Cutting insert 50

[0044] Cutting edge 53

[0045] Guiding sections 54 and 55

[0046] Bottom 71

[0047] Through hole (fastening part) 73

[0048] Screws (fastening components) 75

[0049] Front contact surface 81

[0050] Rear abutment surface 82

[0051] Divide the contact surfaces 82a and 82b

[0052] Cutting tools 100

[0053] Rotation center axis AX1

[0054] The center O of the circumcircle

[0055] Circumcircle R Detailed Implementation

[0056] The preferred embodiments of the cutting inserts and cutting tools provided by the present invention will now be described in detail with reference to the accompanying drawings.

[0057] like Figures 1-6 As shown, the cutting tool 100 provided in this embodiment has a main body 10 and a cutting insert 50. The cutting tool 100 has the cutting insert 50 mounted on the front end of its main body 10. The cutting tool 100 rotates around the rotation center axis AX1. The cutting tool 100 is a cutting tool that performs hole machining on the workpiece by means of the cutting insert 50 located at the front end of the main body 10. The cutting tool 100 can also be used in turning machining of rotating workpieces.

[0058] like Figures 7-11 As shown, the main body 10 has a blade holder 11. The blade holder 11 functions as a blade mounting base for mounting the cutting blade 50 and is formed at the front end of the main body 10. The cutting blade 50 is mounted on the blade holder 11.

[0059] The blade holder 11 includes a lower jaw portion 13 having a seat surface 12 and an upper jaw portion 15 having an abutment surface 14. The lower jaw portion 13 and the upper jaw portion 15 extend toward the front end of the body 10.

[0060] The lower jaw portion 13 and the upper jaw portion 15 are spaced apart from each other. A receiving groove portion 16 for inserting the cutting blade 50 is formed between the lower jaw portion 13 and the upper jaw portion 15. For this receiving groove portion 16, the groove width W1 on the front end side of the main body 10 is narrower than the groove width W2 on the rear end side (see reference). Figure 10 ).

[0061] Regarding the upper jaw portion 15 and lower jaw portion 13 constituting the blade holder 11, when viewed from above, the width of the upper jaw portion 15 is smaller than that of the lower jaw portion 13. The upper jaw portion 15 is located on one side of the blade holder 11 in the width direction and is positioned opposite to the lower jaw portion 13 (see reference). Figure 9 Furthermore, in this embodiment, when viewed from the front end of the main body 10 with the rotation center axis AX1 as a reference, as... Figure 6 As shown, the cutting edge 53 is generally horizontal, and the view of the main body 10 from above refers to the field of view observed in a direction perpendicular to the stated frontal view (vertical direction). A threaded hole 18 is formed on the seat surface 12 of the lower jaw portion 13, into which a fastening component for securing the cutting insert 50, namely a screw 75 (see reference 10000), is screwed. Figure 1 The threaded hole 18 is formed at a position offset from the opposing position of the upper jaw portion 15 in the lower jaw portion 13. Thus, the blade holder 11 of the body 10 has a seat surface 12 of the lower jaw portion 13 and an abutment surface 14 of the upper jaw portion 15, with the threaded hole 18 in the lower jaw portion 13. Furthermore, the upper jaw portion 15 has a clearance recess 19 to prevent interference with the screw 75 screwed into the threaded hole 18 of the lower jaw portion 13.

[0062] In the front view of the main body 10, the threaded hole 18 has a central axis CL1 that is inclined relative to the vertical line PL1 of the seat surface 12 (see reference). Figure 11 Furthermore, in the side view of the main body 10, in the direction away from the abutment surface 14, the central axis CL1 of the threaded hole 18 is inclined towards the rear end relative to the perpendicular line PL1 of the seat surface 12 (see reference). Figure 10 In this way, by tilting the central axis CL1 of the threaded hole 18 relative to the vertical line PL1 of the seat surface 12, the thread in the threaded hole 18 can be increased. In particular, as described in this embodiment, in the front view of the body 10, if the central axis CL1 of the threaded hole is tilted relative to the vertical line PL1, and it extends from one side 10a of the body 10 towards the other side 10b, the thread in the threaded hole 18 can be further increased.

[0063] The main body 10 has a front limiting surface 21 and a rear limiting surface 22. In the blade holder 11, the front limiting surface 21 is located on the front end side of the main body 10, and the rear limiting surface 22 is located on the rear end side of the main body 10. The front limiting surface 21 is formed at the front end of the lower jaw portion 13 constituting the blade holder 11, and the rear limiting surface 22 is formed on the inner side of the blade holder 11. The front limiting surface 21 and the rear limiting surface 22 are formed along the lateral width direction of the blade holder 11.

[0064] exist Figure 9In the top view shown, the front limiting surface 21 and the rear limiting surface 22 are not parallel to each other. Specifically, in the direction from one side 10a of the main body 10 towards the other side 10b, the front limiting surface 21 gradually slopes towards the front end, and the rear limiting surface 22 gradually slopes towards the rear end. Therefore, in Figure 9 In the top view shown, from one side 10a of the main body 10 towards the other side 10b, the front limiting surface 21 and the rear limiting surface 22 move away from each other in a figure-eight shape. Furthermore, the front limiting surface 21 is an inclined surface, gradually tilting towards the front end of the lower jaw 13 from the seat surface 12 towards the bottom of the lower jaw 13. Additionally, a clearance groove 23 is formed between the rear limiting surface 22 and the seat surface 12 to prevent interference with the cutting blade 50.

[0065] The main body 10 has two grooves 31 and 32 (see reference) Figure 8 as well as Figure 9 A groove 31 is formed in the lower jaw portion 13 on the side opposite to the upper jaw portion 15, and another groove 32 is formed in the upper jaw portion 15 on the side opposite to the lower jaw portion 13. The grooves 31 and 32 are formed along the rotation center axis AX1 of the body 10. Furthermore, the body 10 has two outlets 33 and 34. These outlets 33 and 34 are coolant outlets, from which coolant transported via a transport channel (not shown) formed inside the body 10 is discharged. The rear end of one groove 31 communicates with one outlet 33, and the rear end of the other groove 32 communicates with the other outlet 34. The coolant is a fluid supplied from the machine tool side during machining for purposes such as chip removal, tool and workpiece cooling, lubrication, and rust prevention.

[0066] In addition, the main body 10 has a discharge groove 35 (see reference). Figure 7 The discharge groove 35 is a concave groove for discharging chips generated during cutting, and it is formed from the front end side of the main body 10 toward the rear end side of the main body 10.

[0067] like Figures 12-16 As shown, when the cutting blade 50 is installed in the blade holder 11 of the main body 10, the cutting blade 50 is inserted into the blade holder 11 with its rear portion 52 facing the main body 10 (see reference). Figure 2 For example, the cutting insert 50 is formed from various materials such as cemented carbide, cermet, ceramic, ultra-high pressure sintered body, or diamond.

[0068] The cutting insert 50 has a cutting edge 53, two guide portions 54 and 55, and a fluid groove 56. The cutting edge 53, the guide portions 54 and 55, and the fluid groove 56 are located at the front portion 51 of the cutting insert 50. It should be noted that the cutting insert 50 may have multiple cutting edges 53. Furthermore, the cutting insert 50 only needs to have at least two guide portions 54 and 55; therefore, the cutting insert 50 may have three or more guide portions.

[0069] With the cutting insert 50 mounted on the body 10, the cutting edge 53 cuts the workpiece by rotating relative to it. The cutting edge 53 has a center cutting edge 61 and an outer peripheral cutting edge 62. The center cutting edge 61 primarily cuts the center side of the bottom of the machined hole, while the outer peripheral cutting edge 62 primarily cuts the outer peripheral side of the bottom of the machined hole. The center cutting edge 61 protrudes further towards its front end than the outer peripheral cutting edge 62, thus forming a drop plate 63 between the center cutting edge 61 and the outer peripheral cutting edge 62. Compared to the case without the drop plate 63, by providing this drop plate 63, the chip is cut longitudinally along its extension direction, resulting in a smaller chip shape. Therefore, the generated chips are less likely to clog upon discharge.

[0070] When cutting the workpiece, the guide portions 54 and 55 slide in contact with the inner surface of the machined hole in the workpiece, thereby guiding the cutting tool 100. The guide portion 54 is located on the side of the cutting insert 50 opposite to the upper surface 57, and the guide portion 55 is located on the side approximately opposite to the outer peripheral edge of the cutting edge 53 (see reference). Figure 16 The cutting insert 50 is roughly semi-circular when viewed from the front, and the two guide portions 54 and 55 are arc-shaped when viewed from the front (see reference). Figure 16 When cutting the material being cut, a cutting force F is generated on the cutting edge 53 in the cutting insert 50. In a front view, if the center of the circumscribed circle R, which is circumscribed to the outer periphery of the guide portions 54 and 55 and the outer peripheral side of the cutting edge 53, is set to O, then in this embodiment, for example, in a front view, a cutting force F is generated radially outward from the position closer to the center O of the circumscribed circle R than to the center of the cutting edge 53 (see reference). Figure 16 In the cutting insert 50 of this embodiment, guide portions 54 and 55 are provided to hold the generated cutting force F. That is, the guide portions 54 and 55 are configured such that even if the direction of the cutting force F changes, the cutting force F is always between the two guide portions 54 and 55. Therefore, even if the direction of the cutting force F changes, the cutting force F can be withstood by the two guide portions 54 and 55, thereby enabling more stable machining.

[0071] A fluid groove 56 is located between two guide portions 54 and 55. With the cutting blade 50 mounted on the main body 10, the fluid groove 56 is formed in a position communicating with a groove 31 of the main body 10. In the front view, the fluid groove 56 is a concave arc shape. In the front view, the bottom of the fluid groove 56 is more concave inward than its circumscribed circle R (see reference). Figure 6 In the front view, the distance L between the center O of the circumcircle R and the nearest point P in the fluid channel 56 to the center O of the circumcircle R is greater than 1 / 4 of the diameter D of the circumcircle R (see reference). Figure 6 Furthermore, in the front view, the shape of the bottom of the fluid groove 56 is not limited to an arc shape; it can also be formed as a straight line. When the bottom of the fluid groove 56 is formed as an arc shape, both the area of ​​the guide portion 54 can be ensured, and the cross-sectional area of ​​the fluid channel of the fluid groove 56 can be increased. Furthermore, when the bottom of the fluid groove 56 is formed as a straight line shape, the distance L from the center O of the circumcircle R to the nearest point P can be extended. Therefore, the fluid groove 56 can be formed while maintaining a high strength of the cutting blade 50. The shape of the fluid groove 56 can be appropriately selected according to the desired effect.

[0072] The rear portion 52 of the cutting insert 50 is formed into a flat plate shape, and the bottom surface 71 is a smooth surface. When the cutting insert 50 is installed on the insert holder 11 of the main body 10, the bottom surface 71 of its rear portion 52 abuts against the seat surface 12.

[0073] The cutting insert 50 has a through hole 73. The through hole 73 is a fastening part for fixing the cutting insert 50 to the insert holder 11 of the main body 10, and is formed in the rear portion 52 of the cutting insert 50. The through hole 73 is a large-diameter, trumpet-shaped, tapered hole on the upper side. A screw 75, serving as a fastening component for securing the cutting insert 50 to the main body 10, is inserted into the through hole 73 from above. The head 77 of the screw 75 abuts against the inclined surface of the large-diameter portion of the trumpet-shaped tapered hole in the through hole 73 (see reference). Figure 1 ).

[0074] In the front view, the through hole 73 of the cutting blade 50 has a central axis CL2 that is inclined relative to the vertical line PL2 of the bottom surface 71 (see reference). Figure 16 Furthermore, in the side view, in the direction from the upper surface 57 toward the bottom surface 71, the central axis CL2 of the through hole 73 of the cutting blade 50 is inclined rearward relative to the perpendicular line PL2 of the bottom surface 71.

[0075] The cutting insert 50 has a front contact surface 81 and a rear contact surface 82 (see reference). Figure 15The front abutment surface 81 is located on the front side relative to the through hole 73, and the rear abutment surface 82 is located on the rear side relative to the through hole 73. Both the front abutment surface 81 and the rear abutment surface 82 are formed by surfaces facing the rearward side. The front abutment surface 81 is positioned closer to the lower side than the bottom surface 71 that abuts against the seat surface 12 of the insert holder 11, and the front abutment surface 81 is an inclined surface that slopes downward and forward. It should be noted that the front abutment surface 81 is not necessarily an inclined surface; it can also be a vertical surface. On the other hand, if the front abutment surface 81 is set as an inclined surface with an obtuse angle relative to the bottom surface 71, it can more effectively withstand the cutting force F generated downward toward the cutting insert 50 during machining. The rear abutment surface 82 is composed of two divided abutment surfaces 82a and 82b, which are divided left and right. Because there is a recess between the dividing abutment surface 82a and the distributing abutment surface 82b, when the cutting blade 50 is installed on the main body 10, the cutting blade 50 will necessarily abut against the rear limiting surface 22 of the blade holder 11 on the outer side of the rear abutment surface 82, so that the cutting blade 50 can be fixed without loosening.

[0076] exist Figure 15 In the top view shown, the front abutment surface 81 and the rear abutment surface 82 are not parallel to each other. Specifically, the front abutment surface 81 gradually slopes forward from one side 50a of the cutting insert 50 to the other side 50b, while the rear abutment surface 82 gradually slopes backward from one side 50a of the cutting insert 50 to the other side 50b. Thus, in... Figure 15 In the top view shown, from one side 50a of the cutting blade 50 towards the other side 50b, the front contact surface 81 and the rear contact surface 82 move away from each other in a figure-eight shape (see reference). Figure 15 During cutting, the cutting insert 50 is subjected to a cutting force along the rear limiting surface 22 toward the other side 10b of the body 10. At this time, since the front limiting surface 21 of the body 10, which is abutted by the front abutting surface 81 of the cutting insert 50, is inclined in the opposite direction to the rear limiting surface 22, the cutting insert 50, which is to be moved toward one side 10b of the body 10, can be pressed down.

[0077] In addition, such as Figure 17 and Figure 18 As shown, with the cutting insert 50 positioned in the insert holder 11 of the main body 10, the central axis CL2 of the through hole 73 is offset relative to the central axis CL1 of the threaded hole 18 formed in the lower jaw portion 13 constituting the insert holder 11. Specifically, the central axis CL2 of the through hole 73 is more biased toward the front end side and the other side 10b of the main body 10 than the central axis CL1 of the threaded hole 18.

[0078] In this way, by misaligning the central axis CL2 of the through hole 73 of the cutting insert 50 with the central axis CL1 of the threaded hole 18 of the insert holder 11, when the cutting insert 50 is assembled onto the body 10, after the front abutment surface 81 abuts against the front limiting surface 21 of the insert holder 11, the cutting insert 50 slides towards one side 10a of the body 10 on the front limiting surface 21 while retracting towards the rear of the body 10. This allows the cutting insert 50 to easily abut against both the front limiting surface 21 and the rear limiting surface 22.

[0079] Next, the process of mounting the cutting insert 50 onto the main body 10 will be described. To mount the cutting insert 50 onto the main body 10, the cutting insert 50 is brought close to the insert holder 11 of the main body 10 from the front end side. At this time, the rear portion 52 of the cutting insert 50 is oriented towards the main body 10, and the vertical position of the cutting insert 50 is aligned with the main body 10 (see reference). Figure 2 ).

[0080] Then, the cutting insert 50 is inserted into the receiving groove 16 formed in the insert holder 11 of the main body 10, so that it is received between the lower jaw portion 13 and the upper jaw portion 15. In this way, the cutting insert 50 is elastically clamped and held in the receiving groove 16, and for the receiving groove 16, the groove width W1 on the front end side of the main body 10 is narrower than the groove width W2 on the rear end side. However, this holding state is only a temporary fixed state, and the holding force at this time is not a fixed force that can withstand the cutting force during cutting.

[0081] Next, the screw 75 is inserted into the through hole 73 of the cutting blade 50 and screwed into the threaded hole 18 of the lower jaw 13. At this time, the cutting blade 50 is held in the receiving groove 16 of the blade holder 11, so the screw 75 can be tightened without holding the cutting blade 50.

[0082] In this way, if the screw 75 inserted into the through hole 73 of the cutting blade 50 is screwed into the threaded hole 18 of the lower jaw 13, the cutting blade 50 is fixed to the lower jaw 13 in a state of close contact with the seat surface 12 of the lower jaw 13 and the abutment surface 14 of the upper jaw 15, thereby the cutting blade 50 is installed on the blade holder 11.

[0083] Since the central axis CL2 of the through hole 73 of the cutting insert 50 is more biased towards the front end and the other side 10b of the main body 10 compared to the central axis CL1 of the threaded hole 18, as mentioned above, after the front abutment surface 81 abuts against the front limiting surface 21 of the insert holder 11, the cutting insert 50 slides towards one side 10a of the main body 10 on the front limiting surface 21 while retracting towards the rear of the main body 10. Thus, the cutting insert 50 is mounted on the insert holder 11 with the front abutment surface 81 and the rear abutment surface 82 abutting against the front limiting surface 21 and the rear limiting surface 22 of the insert holder 11, respectively. Therefore, the cutting insert 50 is fixed to the insert holder 11 with a high holding force and is not loose. Moreover, the cutting insert 50 is mounted on the main body 10 with the center of its circumscribed circle R coinciding with the rotation center axis AX1 of the main body 10.

[0084] Furthermore, after the cutting insert 50 is installed on the insert holder 11, the fluid groove 56 located between the guide portions 54 and 55 of the cutting insert 50 is connected to the groove portion 31 of the main body 10.

[0085] In this way, in the cutting tool 100, the cutting insert 50 is mounted on the insert holder 11 of the main body 10, and the coolant discharged through the outlet 33 is transported to the cutting area through the groove 31 and the fluid groove 56. In addition, the coolant discharged through the outlet 34 is transported to the cutting area through the groove 32. Therefore, the cutting insert 50 can be cooled and chips can be removed more effectively by the coolant.

[0086] Then, when the cutting tool 100 performs hole machining on the workpiece, the rotational force acting on the cutting insert 50 is borne by the seat surface 12 and the abutment surface 14 of the insert holder 11 constituting the main body 10. Furthermore, the pressing force generated by pressing the cutting tool 100 toward the rear of the cutting insert 50 is borne by the front limiting surface 21 and the rear limiting surface 22 of the insert holder 11 of the main body 10, which abut against the front abutment surface 81 and the rear abutment surface 82, respectively.

[0087] As described above, in this embodiment, the cutting insert 50 integrates the function of a guide pad, which is screwed onto the retainer, by including two guide portions 54 and 55 that slide in contact with the inner surface of the machining hole. This reduces the number of components. In this way, the thickness of the cutting insert 50 is maintained to ensure sufficient strength, while also enabling tool miniaturization. Furthermore, coolant can be delivered via the fluid channel 56 to the cutting point where the cutting edge 53 cuts the workpiece.

[0088] Furthermore, the distance L between the center O of the circumcircle R and the nearest point P in the fluid channel 56 to the center O of the circumcircle R is greater than 1 / 4 of the diameter D of the circumcircle R. Therefore, by providing the fluid channel 56, coolant can be delivered to the cutting edge of the material being cut while maintaining sufficient necessary strength.

[0089] In addition, the rear part 52 has a through hole 73 for inserting a screw 75, so that the screw 75 can be inserted into the through hole 73 to easily fasten the cutting blade 50 to the body 10.

[0090] Furthermore, by bringing the front abutment surface 81, which is closer to the front side than the through hole 73 and closer to the bottom side than the bottom surface 71, into contact with the front limiting surface 21 of the main body 10, the main body 10 can withstand the cutting force F generated when the cutting edge 53 cuts the material being cut, thus mitigating the stress acting on the screw 75 during cutting.

[0091] Furthermore, in the cutting insert 50 provided in this embodiment, the cutting insert 50 is fastened to the fastening portion of the main body 10, namely the through hole 73, and has a front abutment surface 81 and a rear abutment surface 82 facing rearward on its front side and rear side, respectively. Therefore, by having the front abutment surface 81 and the rear abutment surface 82 abut against the main body 10, the main body 10 can better withstand the cutting force F generated during cutting. As a result, the load of the screw 75 on the fastening position in the through hole 73 can be reduced, thereby enabling stable cutting. In addition, by having the front abutment surface 81 and the rear abutment surface 82 abut against the main body 10, the main body 10 can be easily positioned.

[0092] Moreover, in the front view, the cutting blade 50 is roughly semi-circular in shape, thus ensuring high strength compared to cutting blades that are only plate-shaped.

[0093] Furthermore, this invention is not limited to the specific examples described above. Those skilled in the art can make appropriate design modifications to these specific examples, and as long as they possess the features of this invention, they are all included within the scope of this invention. The elements, their configurations, conditions, shapes, etc., of the specific examples described above are not limited to the illustrative content and can be appropriately modified. As long as no technical contradiction arises, the combination of the elements of the specific examples described above can be appropriately changed.

Claims

1. A cutting insert, mounted on a body for drilling a workpiece, the cutting insert comprising: A cutting edge, used to cut the material being cut; At least two guide portions slide in contact with the inner surface of the machining hole formed by drilling in the workpiece; Fastening part, used to fix the cutting blade to the body, wherein, The cutting blade has at least one rearward-facing contact surface on both the front and rear sides relative to the fastening part.

2. The cutting insert according to claim 1, wherein, In a front view, the cutting blade is generally semi-circular in shape.

3. The cutting insert according to claim 1, wherein, In the bottom view, the front abutment surface and the rear abutment surface are not parallel to each other.

4. The cutting insert according to claim 3, wherein, In the bottom view, from one side to the other, the abutment surfaces on the front and rear sides move away from each other.

5. The cutting insert according to claim 1, wherein, The rear abutment surface is composed of at least two segmented abutment surfaces.

6. A cutting tool, comprising: The cutting insert according to any one of claims 1 to 5; as well as The main body on which the cutting blade is mounted.

7. The cutting tool according to claim 6, wherein, In the front view, the cutting blade is mounted on the body with the center of its circumscribed circle coinciding with the rotation center axis of the body. The circumscribed circle is externally connected to the guide portion and the outer peripheral end of the cutting edge.

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