Cutting insert and cutting tool

Abstract

Provided are a cutting insert and a cutting tool equipped with the cutting insert, the cutting tool being compact while ensuring sufficient strength, and being capable of satisfactorily conveying a coolant to a cutting site. A cutting insert (50) which is attached to a main body (10) when drilling a material to be cut, the cutting insert (50) comprising: a cutting edge (53) for cutting the material to be cut; at least two guides 54, 55 that are in sliding contact with the inner surface of a machined hole of the material to be cut formed by drilling; and a fluid groove (56) provided between the guide sections (54, 55), the fluid groove (56) being recessed inward with respect to a circumscribed circle (R) in a front view, and the circumscribed circle (R) being circumscribed with the guide sections (54, 55) and the outer peripheral end of the cutting blade (53).

Description

Technical Field

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

[0002] Patent Document 1 discloses a drilling cutting tool in which a cutting insert is mounted on a insert mounting base of the main body. Patent Document 2 discloses a cutting tool with a groove for supplying cutting oil on the outer periphery of the main body. Furthermore, Patent Document 3 discloses a cutting tool equipped with a cutting insert 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: Japanese Patent No. 6849136

[0007] Patent Document 3: International Publication No. 2021 / 214747

[0008] Technical issues

[0009] However, the cutting tool described in Patent Document 1 uses screws to fix the cutting blade and two guide pads to the main body. Because this cutting tool has many structural components, miniaturization is difficult. Therefore, even if all components are housed within a limited space, the thickness of the cutting blade or the main body cannot be adequately ensured, resulting in reduced structural strength and hindering efficient machining. Furthermore, even if the cutting blade can be miniaturized, it is difficult to provide a flow path for supplying coolant to the cutting area, as described in Patent Document 2. Additionally, in Patent Document 3, a recess is formed on the cutting blade, but this recess is where the front end of the main body enters and is fixed to the main body, making it difficult to use this recess as a coolant supply path.

[0010] The present invention was made in view of the above-mentioned problems, and its object is to provide a cutting insert and a cutting tool equipped with the cutting insert, which can achieve tool miniaturization while ensuring sufficient strength, and has the ability to effectively deliver coolant to the cutting part. Summary of the Invention

[0011] One aspect of the present invention relates to a cutting insert mounted on a body when drilling a workpiece, comprising: a cutting edge for cutting the workpiece; at least two guide portions that slide in contact with the inner surface of a hole formed by drilling in the workpiece; and a fluid groove disposed between the guide portions, wherein, in a front view, the fluid groove is recessed inward relative to a circumscribed circle, the circumscribed circle being externally connected to the guide portions and the outer peripheral end of the cutting edge.

[0012] The cutting insert with the above structure has two guide portions that slide in contact with the inner surface of the machined hole. This integrates the function of the guide pad, which originally needed to be screwed onto the tool holder, into the cutting insert, thereby reducing the number of structural components. Thus, while maintaining the thickness of the cutting insert to ensure sufficient strength, tool miniaturization is achieved. Furthermore, coolant can be delivered to the cutting area where the workpiece is cut via the cutting edge through a fluid channel.

[0013] In the front view, the distance between the center of the circumcircle and the nearest point in the fluid channel to the center of the circumcircle can be set to be greater than 1 / 4 of the diameter of the circumcircle.

[0014] In a front view, the bottom of the fluid tank can be formed into an arc shape.

[0015] In a front view, the bottom of the fluid channel can be formed as a straight line.

[0016] It may have fastening parts for fastening to the body by means of fasteners.

[0017] The side that is forward of the fastener and downward of the bottom surface may have an abutting surface.

[0018] The contact surface can be an inclined surface that is tilted relative to the bottom surface.

[0019] The cutting edge may have an outer peripheral edge and a central edge that protrudes towards the front end relative to the outer peripheral edge, forming a step between the outer peripheral edge and the central edge.

[0020] One aspect of the present invention relates to a cutting tool comprising the aforementioned cutting insert and a body for mounting the cutting insert.

[0021] Cutting tools can be drilling tools used to drill holes in the material being cut.

[0022] The cutting insert of the cutting tool can be mounted on the body with the center of its circumscribed circle aligned with the rotation axis of the body.

[0023] According to the present invention, a cutting insert and a cutting tool equipped with the cutting insert are provided, which can achieve tool miniaturization while ensuring sufficient strength, and can effectively deliver coolant to the cutting area. Attached Figure Description

[0024] Figure 1 This is a perspective view of the cutting tool according to this embodiment.

[0025] Figure 2 This is an exploded perspective view of the cutting tool according to this embodiment.

[0026] Figure 3 This is a top view of the cutting tool.

[0027] Figure 4 This is the right view of the cutting tool.

[0028] Figure 5 This is a bottom view of the cutting tool.

[0029] Figure 6 This is the front view of the cutting tool.

[0030] Figure 7 It is a three-dimensional image of the main body.

[0031] Figure 8 This is a three-dimensional view taken from the bottom side of the main body.

[0032] Figure 9 This is a top view of the main body.

[0033] Figure 10 yes Figure 9 Cross-sectional view of XX.

[0034] Figure 11 yes Figure 9 Sectional view of XI-XI.

[0035] Figure 12 It is a 3D view of the cutting blade.

[0036] Figure 13 This is a top view of the cutting blade.

[0037] Figure 14 This is a right view of the cutting blade.

[0038] Figure 15 This is a bottom view of the cutting blade.

[0039] Figure 16 This is the front view of the cutting blade.

[0040] Figure 17 yes Figure 3 Sectional view of XVII-XVII.

[0041] Figure 18 yes Figure 3 Sectional view of XVIII-XVIII.

[0042] Explanation of main component symbols

[0043] Main body 10

[0044] Cutting insert 50

[0045] Cutting edge 53

[0046] Guiding parts 54, 55

[0047] Fluid tank 56

[0048] Center Blade 61

[0049] Peripheral blade 62

[0050] Step 63

[0051] Bottom 71

[0052] Through hole (fastening part) 73

[0053] Screws (fasteners) 75

[0054] Cutting tool 100

[0055] Rotation center axis AX1

[0056] circumcircle diameter D

[0057] Distance L

[0058] The center O of the circumcircle

[0059] Recently click P

[0060] Circumcircle R Detailed Implementation

[0061] Hereinafter, with reference to the accompanying drawings, preferred embodiments of the cutting inserts and cutting tools according to the present invention will be described in detail.

[0062] like Figures 1-6 As shown, the cutting tool 100 of 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 the main body 10. The cutting tool 100 rotates around the rotation center axis AX1. The cutting tool 100 is a cutting tool that performs drilling operations on the workpiece material 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 operations to cut rotating workpiece material.

[0063] like Figures 7-11 As shown, the main body 10 has a blade groove 11. The blade groove 11 serves 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 in the blade groove 11.

[0064] The blade groove 11 includes a lower jaw portion 13 with a seat surface 12 and an upper jaw portion 15 with an abutment surface 14, the lower jaw portion 13 and the upper jaw portion 15 extending toward the front end of the body 10.

[0065] The lower jaw portion 13 and the upper jaw portion 15 are spaced apart from each other, and a receiving groove 16 for inserting the cutting blade 50 is formed between the lower jaw portion 13 and the upper jaw portion 15. The groove width W1 of the receiving groove 16 on the front end side of the main body 10 is narrower than the groove width W2 of the receiving groove 16 on the rear end side of the main body 10 (see reference). Figure 10 ).

[0066] The upper jaw portion 15 and the lower jaw portion 13 that constitute the blade groove 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 groove 11 in the width direction and is opposite to the lower jaw portion 13 (see reference). Figure 9 Additionally, "viewing the main body 10 from above" refers to, in this embodiment, when viewed from the front end of the main body 10 with the rotation center axis AX1 as a reference, such as... Figure 6 As shown, the cutting edge 53 is approximately horizontal, and the field of view is perpendicular to this direction (vertical direction) relative to the direction viewed from the front. A threaded hole 18 is formed in the seat surface 12 of the lower jaw portion 13, into which a fastener, namely a screw 75 (see reference 12), for securing the cutting insert 50 is screwed (see reference 12). Figure 1 The threaded hole 18 is formed at a position offset from the upper jaw 15 in the lower jaw portion 13. Thus, the blade groove 11 of the body 10 has a seat surface 12 of the lower jaw portion 13 with the threaded hole 18 and an abutment surface 14 of the upper jaw portion 15. Furthermore, the upper jaw portion 15 has a relief recess 19 to prevent interference with the screw 75 screwed into the threaded hole 18 of the lower jaw portion 13.

[0067] 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 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 Thus, 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 in this embodiment, in the front view of the body 10, the central axis CL1 of the threaded hole is tilted relative to the vertical line PL1, and it appears to move from one side 10a of the body 10 towards the other side 10b, thereby further increasing the thread in the threaded hole 18.

[0068] The main body 10 has a front constraint surface 21 and a rear constraint surface 22. In the blade groove 11, the front constraint surface 21 is provided on the front end side of the main body 10, and the rear constraint surface 22 is provided on the rear end side of the main body 10. The front constraint surface 21 is formed at the front end of the lower jaw portion 13 constituting the blade groove 11, and the rear constraint surface 22 is formed on the inner side of the blade groove 11. The front constraint surface 21 and the rear constraint surface 22 are formed along the transverse width direction of the blade groove 11.

[0069] exist Figure 9 In the top view shown, the front constraint surface 21 and the rear constraint surface 22 are not parallel to each other. Specifically, in the direction from one side 10a of the main body 10 to the other side 10b, the front constraint surface 21 gradually slopes towards the front end, and the rear constraint 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 to the other side 10b, the front constraint surface 21 and the rear constraint surface 22 separate into a V-shape. Furthermore, the front constraint surface 21 is an inclined surface, gradually tilting towards the front end of the lower jaw 13 in the direction from the seat surface 12 of the lower jaw 13 towards the bottom of the lower jaw 13. Additionally, a clearance groove 23 is formed between the rear constraint surface 22 and the seat surface 12 to prevent interference with the cutting blade 50.

[0070] The main body 10 has two grooves 31 and 32 (see reference) Figure 8 and Figure 9 A groove 31 is formed on the side of the lower jaw 13 opposite to the upper jaw 15, and another groove 32 is formed on the side of the upper jaw 15 opposite to the lower jaw 13. These grooves 31 and 32 are formed along the rotation center axis AX1 of the body 10. Additionally, the body 10 has two outlets 33 and 34. These outlets 33 and 34 are coolant outlets, from which coolant supplied through a supply path (not shown) formed inside the body 10 is discharged. The rear end of one groove 31 is connected to one outlet 33 nearby, and the rear end of the other groove 32 is connected to the other outlet 34. The coolant is a fluid supplied from the machine tool side during machining for purposes such as chip removal, cooling of tools and workpiece material, lubrication, and rust prevention.

[0071] Additionally, the main body 10 has a discharge groove 35 (see reference). Figure 7 The discharge groove 35 is a concave groove that discharges chips generated during cutting, and is formed from the front end side of the main body 10 toward the rear end side of the main body 10.

[0072] like Figures 12-16 As shown, when the cutting blade 50 is installed in the blade groove 11 of the main body 10, the cutting blade 50 is inserted into the blade groove 11 with its rear portion 52 facing the main body 10 (see reference). Figure 2The cutting insert 50 is formed from various materials such as superhard alloys, cermets, ceramics, ultra-high pressure sintered bodies, or diamond.

[0073] The cutting insert 50 has a cutting edge 53, two guide portions 54 and 55, and a fluid groove 56. The cutting edge 53, guide portions 54 and 55, and fluid groove 56 are disposed at the front part 51 of the cutting insert 50. Alternatively, 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, it may also have three or more guide portions.

[0074] With the cutting insert 50 mounted on the main body 10, the cutting edge 53 rotates relative to the workpiece, thereby cutting the workpiece. The cutting edge 53 has a central cutting edge 61 and an outer peripheral cutting edge 62. The central cutting edge 61 mainly cuts the center side of the bottom of the machined hole, and the outer peripheral cutting edge 62 mainly cuts the outer peripheral side of the bottom of the machined hole. The central cutting edge 61 protrudes further forward than the outer peripheral cutting edge 62, thus forming a step 63 between the central cutting edge 61 and the outer peripheral cutting edge 62. Compared with the case without the step 63, when the step 63 is provided, the chip can be cut longitudinally along its extension direction, making the chip shape simpler. Therefore, clogging will not easily occur when the generated chips are discharged.

[0075] When cutting the workpiece, the guide portions 54 and 55 slide in contact with the inner surface of the machined hole in the workpiece to guide the cutting tool 100. The guide portion 54 is located on the side opposite to the upper surface 57 of the cutting insert 50, and the guide portion 55 is located on the side substantially opposite to the outer peripheral end of the cutting edge 53 (see reference). Figure 16 In the front view, the cutting blade 50 is roughly semi-circular in shape, and the two guide portions 54 and 55 are formed in an arc shape (see reference). Figure 16 Here, when cutting the material being cut, a cutting force F is generated on the cutting edge 53 of the cutting insert 50. In the front view, the center of the circumscribed circle R, which is circumscribed to the outer periphery of the guide portions 54, 55 and the cutting edge 53, is set to O. In this embodiment, for example, in the front view, the cutting force F is generated radially outward at a position closer to the center O of the circumscribed circle R than 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, because of the guide portions 54 and 55, even if the direction of the cutting force F changes, the cutting force F always remains between the two guide portions 54 and 55. Therefore, even if the direction of the cutting force F changes, the two guide portions 54 and 55 can withstand the cutting force F, thereby achieving more stable machining.

[0076] A fluid groove 56 is disposed between two guide portions 54 and 55. The fluid groove 56 is formed in a position where it connects to a groove 31 on one side of the main body 10 when the cutting blade 50 is mounted on the main body 10. In the front view, the fluid groove 56 is an arc-shaped recess. In the front view, the bottom of the fluid groove 56 is further recessed inward than the 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 tank 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 In the front view, the bottom shape of the fluid channel 56 is not limited to an arc shape; it can also be a straight line. When the bottom of the fluid channel 56 is formed in an arc shape, the flow path cross-sectional area of ​​the fluid channel 56 can be increased while ensuring the area of ​​the guide portion 54. Conversely, when the bottom of the fluid channel 56 is formed in a straight line, the distance L between the center O of the circumscribed circle R and the point P closest to the center O of the circumscribed circle R can be extended, thereby forming the fluid channel 56 while maintaining the high strength of the cutting tool 50. The shape of the fluid channel 56 can be appropriately selected according to the desired effect.

[0077] 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 in the insert groove 11 of the main body 10, the bottom surface 71 of the rear portion 52 abuts against the seat surface 12.

[0078] The cutting insert 50 has a through hole 73. The through hole 73 is a fastening portion that secures the cutting insert 50 to the insert groove 11 of the body 10, and is formed at the rear 52 of the cutting insert 50. The through hole 73 is a large-diameter, flared, tapered hole on its upper side. A fastener, namely a screw 75, that secures the cutting insert 50 to the body 10 is inserted into the through hole 73 from above. The head 77 of the screw 75 abuts against the beveled surface of the large-diameter portion of the flared, tapered hole in the through hole 73 (see reference). Figure 1 ).

[0079] 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 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 vertical line PL2 of the bottom surface 71.

[0080] 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 disposed on the front side relative to the through hole 73, and the rear abutment surface 82 is disposed 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 disposed below the bottom surface 71 that abuts against the seat surface 12 of the insert groove 11, and the front abutment surface 81 is an inclined surface that slopes downward and forward. However, the front abutment surface 81 does not necessarily have to be an inclined surface; for example, it can be a vertical surface. On the other hand, if the front abutment surface 81 is formed into an inclined surface with an obtuse angle between it and the bottom surface 71, the cutting force F generated downward toward the cutting insert 50 during machining can be more effectively withstood. The rear abutment surface 82 is composed of two divided abutment surfaces 82a and 82b, which are divided into left and right sides. Because there is a recess between the split abutment surface 82a and the split abutment surface 82b, when the cutting blade 50 is installed on the main body 10, the cutting blade 50 will inevitably abut against the rear constraint surface 22 of the blade groove 11 on the outer side of the rear abutment surface 82, which can firmly fix the cutting blade 50 and prevent it from shaking.

[0081] The front abutment surface 81 and the rear abutment surface 82 are in Figure 15 In the plan view, they are not parallel to each other. Specifically, the front abutment surface 81 gradually slopes forward from one side 50a of the cutting insert 50 towards the other side 50b, and the rear abutment surface 82 gradually slopes backward from one side 50a of the cutting insert 50 towards the other side 50b. Therefore, in Figure 15 In the plan view, from one side 50a of the cutting blade 50 towards the other side 50b, the front abutment surface 81 and the rear abutment surface 82 separate into a V-shape (see reference). Figure 15 Here, the cutting insert 50 will be subjected to a cutting force along the rear constraint surface 22 toward the other side 10b of the body 10 during cutting. At this time, since the front constraint surface 21 of the body 10 that abuts the front contact surface 81 of the cutting insert 50 is inclined in the opposite direction to the rear constraint surface 22, the cutting insert 50 can be effectively suppressed from moving toward the side 10b of the body 10.

[0082] In addition, such as Figure 17 and Figure 18 As shown, when the cutting insert 50 is placed in the insert groove 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 groove 11. Specifically, compared to the central axis CL1 of the threaded hole 18, the central axis CL2 of the through hole 73 is more biased towards the front end side and the other side 10b of the main body 10.

[0083] Thus, since the central axis CL2 of the through hole 73 of the cutting insert 50 is misaligned with the central axis CL1 of the threaded hole 18 formed in the lower jaw portion 13 constituting the insert groove 11, when the cutting insert 50 is assembled onto the body 10, after the front abutment surface 81 abuts against the front constraint surface 21 of the insert groove 11, the cutting insert 50 slides along the front constraint surface 21 toward one side 10a of the body 10 while being led to the rear of the body 10. This makes it easier for the cutting insert 50 to abut against both the front constraint surface 21 and the rear constraint surface 22.

[0084] Next, the process of mounting the cutting blade 50 onto the main body 10 will be described.

[0085] To mount the cutting insert 50 onto the body 10, the cutting insert 50 is brought close to the insert groove 11 of the body 10 from the front end side. At this time, the rear portion 52 of the cutting insert 50 faces the body 10, and the vertical position of the cutting insert 50 is aligned with the body 10 (see reference). Figure 2 ).

[0086] Then, the cutting insert 50 is inserted into the receiving groove 16 formed in the insert groove 11 of the main body 10, and received between the lower jaw portion 13 and the upper jaw portion 15. Thus, the cutting insert 50 is elastically clamped and held in the receiving groove 16, and the groove width W1 of the receiving groove 16 on the front end side of the main body 10 is narrower than the groove width W2 of the receiving groove 16 on the rear end side of the main body 10. Furthermore, this holding state is a temporary fixed state, and the holding force at this time is not a fixed force capable of withstanding the cutting force during cutting.

[0087] 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, since the cutting blade 50 is held in the receiving groove 16 of the blade groove 11, the screw 75 can be tightened without holding the cutting blade 50.

[0088] Thus, after screwing the screw 75, which inserts the through hole 73 of the cutting blade 50, 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 tight contact with the seat surface 12 of the lower jaw 13 and the abutment surface 14 of the upper jaw 15, thereby installing the cutting blade 50 in the blade groove 11.

[0089] Here, 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 described above, after the front abutment surface 81 abuts against the front constraint surface 21 of the insert groove 11, the cutting insert 50 slides along the front constraint surface 21 toward one side 10a of the main body 10 while being introduced to the rear of the main body 10. Thus, the cutting insert 50 is installed on the insert groove 11 with the front abutment surface 81 and the rear abutment surface 82 abutting against the front constraint surface 21 and the rear constraint surface 22, respectively. Therefore, the cutting insert 50 is fixed in the insert groove 11 with a very high holding force and will not wobble. Furthermore, the cutting insert 50 is installed on the main body 10 with the center of its circumscribed circle R aligned with the rotation center axis AX1 of the main body 10.

[0090] In addition, when the cutting blade 50 is installed in the blade groove 11, the fluid groove 56 provided between the guide portions 54 and 55 of the cutting blade 50 is connected to the groove portion 31 of the main body 10.

[0091] The cutting tool 100 has a cutting insert 50 installed in the insert groove 11. Coolant discharged from the outlet 33 is fed into the cutting part through the groove 31 and the fluid groove 56. In addition, coolant discharged from the outlet 34 is fed into the cutting part through the groove 32. Therefore, the cooling of the cutting insert 50 and the removal of chips are well achieved by means of coolant.

[0092] When drilling a hole in the workpiece material using the cutting tool 100, the rotational force acting on the cutting insert 50 is borne by the seat surface 12 and the abutment surface 14 of the insert groove 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 constraint surface 21 and the rear constraint surface 22 of the insert groove 11 of the main body 10, which abut against the front abutment surface 81 and the rear abutment surface 82.

[0093] As described above, in this embodiment, the cutting insert 50 has two guide portions 54 and 55 that slide in contact with the inner surface of the machined hole, thereby integrating the function of the guide pad, which originally needed to be mounted on the tool holder with screws, into the cutting insert 50, reducing the number of structural components. Thus, while maintaining the thickness of the cutting insert 50 to ensure sufficient strength, tool miniaturization is achieved. Furthermore, coolant can be supplied to the cutting area where the material being cut is cut by the cutting edge 53 via the fluid channel 56.

[0094] 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 setting the fluid channel 56, sufficient necessary strength can still be maintained while delivering coolant to the cutting part of the workpiece.

[0095] Furthermore, since the rear part 52 has a through hole 73 for inserting a screw 75, the cutting blade 50 can be easily fastened to the body 10 by inserting the screw 75 into the through hole 73.

[0096] In addition, by making the front abutment surface 81, which is further forward than the through hole 73 and lower than the bottom surface 71, abut against the front constraint surface 21 of the main body 10, the main body 10 can bear the cutting force F generated when the cutting edge 53 cuts the material being cut, thereby easing the stress acting on the screw 75 during cutting.

[0097] Furthermore, this invention is not limited to the specific embodiments described above. Appropriate design modifications made to these specific embodiments by those skilled in the art, as long as they possess the features of this invention, are also included within the scope of this invention. The elements, their configurations, conditions, shapes, etc., included in the above specific embodiments are not limited to the illustrative content and can be appropriately modified. As long as no technical contradiction arises, the elements included in the above specific embodiments can also be appropriately combined and modified.

Claims

1. A cutting insert, mounted on a body for drilling a workpiece, the cutting insert comprising: 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; A fluid groove is disposed between the guide portions. In a front view, the fluid groove is recessed inward relative to the circumscribed circle, which is externally connected to the guide portions and the outer peripheral end of the cutting edge.

2. The cutting insert according to claim 1, wherein, In the front view, the distance between the center of the circumscribed circle and the nearest point in the fluid channel to the center of the circumscribed circle is greater than 1 / 4 of the diameter of the circumscribed circle.

3. The cutting insert according to claim 1, wherein, In the front view, the bottom of the fluid channel is formed in an arc shape.

4. The cutting insert according to claim 1, wherein, In the front view, the bottom of the fluid channel is formed as a straight line.

5. The cutting insert according to claim 1, wherein, It has a fastening part for fastening onto the body by means of fasteners.

6. The cutting insert according to claim 5, wherein, The side that is forward of the fastening part and downward of the bottom surface has an abutting surface.

7. The cutting insert according to claim 6, wherein, The contact surface is an inclined surface that is tilted relative to the bottom surface.

8. The cutting insert according to claim 1, wherein, The cutting edge has an outer peripheral edge and a central edge that protrudes towards the front end relative to the outer peripheral edge, forming a step between the outer peripheral edge and the central edge.

9. A cutting tool, comprising: The cutting insert according to any one of claims 1 to 8; The main body for mounting the cutting blade.

10. The cutting tool according to claim 9, wherein, The cutting blade is mounted on the body with the center of its circumscribed circle aligned with the rotation axis of the body.

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