Cutting tool body and cutting insert

Abstract

To provide a body of a cutting tool which enables further improvement of support rigidity of a cutting insert, and to provide the cutting insert.SOLUTION: A body 20 of a cutting tool 10 includes: an insert seat 22 provided on a leading end part 20t of the body 20; a screw hole 21 into which a fastening screw is screwed; a deep seat portion 23 provided at a deep part in the insert seat in an axial direction of the screw hole; a receiving portion 24 configured to receive a contact portion 44 of the cutting insert 40; a wall portion 26 having a base-end side rotation inhibition portion 26s which serves as a rotation stopper of the cutting insert 40; and a shallow seat portion 25 having a depth of a seat which is shallower than a part provided with the receiving portion 24. The base-end side rotation inhibition portion 26s is located at a position which does not overlap the deep seat portion 23 when viewed along an axis of the screw hole 21 in the body 20.SELECTED DRAWING: Figure 11

Description

[Technical Field]

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

[0002] For cutting tools used for internal face grooving, the cutting depth should be determined according to the internal face grooving depth. If the deflection of the body during cutting increases, the work material and the discharge performance will decrease. There are unique issues such as interference with the cutting insert causing damage to the cutting edge. In the past, various improved technologies have been proposed to address these issues. (See, for example, Patent Documents 1 and 2). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Special Publication No. 2010-535638 [Patent Document 2] Patent No. 6976522 Summary of the Invention [Problem to be solved by the invention]

[0004] However, even though cutting tools have been improved in this way, the thickness of the cutting tool body Considering the support rigidity and other factors, there is room for further improvement. If the body's rigidity is insufficient, chattering will occur, especially when machining internal diameters. There are effects such as:

[0005] Therefore, the present invention is intended to further improve the supporting rigidity of the cutting insert. The present invention aims to provide a cutting tool body and a cutting insert having the same. [Means for solving the problem]

[0006] In order to solve this problem, the present inventor has developed a cutting insert and a body structure that supports the cutting insert. The cutting insert fits snugly against the insert seat at the tip of the body. The cutting edge is placed on the inner diameter end face of the rotating workpiece and is fixed vertically with a fixing screw. When cutting in the direction, if the cutting edge is the force point and the fixing screw (thread hole) is the fulcrum, The base end opposite the blade is the point of action, and the reaction force acting from this base end is distributed to the body. It is important to reduce the amount of deflection of the cutting edge during cutting. From this point of view, increasing the distance from the fulcrum to the point of application reduces the deflection of the force point (cutting edge). This is one possible measure that can be taken in that it makes it easier to reduce the amount of cutting. The body (insert seat) had to be lengthened to match the length of the insert. Even if the reaction force acting from the base end is successfully absorbed, the essential body itself will not bend. The inventors have been working on this type of By considering these issues with a view to solving them, we were able to gain insights that could lead to solutions.

[0007] The present invention was conceived based on this finding, and one aspect thereof is a cutting tool body. And, An insert seat for attaching a cutting insert provided at the tip of the body; , A fixing screw for fixing the cutting insert attached to the insert seat is screwed into the fixing screw. Screw holes and a deep seat portion provided in a deep portion of the insert seat in the axial direction of the screw hole; The deep seat portion faces the abutment portion formed on the bottom portion facing the insert seat of the cutting insert. a receiving portion that receives the abutting portion at a position where the abutting portion is to be fitted; It consists of an inner wall surface that forms the insert seat and contacts the peripheral side of the cutting insert. At least two base end rotation restraining portions that prevent the cutting insert from rotating around the axis. a wall portion, The part of the insert seat that has a receiving part formed in the part that includes the base-end rotation prevention part A shallow seat with a shallower seat depth than the Equipped with When viewed along the axis of the screw hole, the base end rotation prevention part is positioned so that it does not overlap with the deep seat part. This is the body of the filling.

[0008] According to the cutting tool body of this aspect, the side opposite to the cutting edge (i.e., the base end of the body) In the area (near the insert seat), there is a shallow seat that is shallower than the part of the insert seat where the receiving part is located. Since it is formed, the thickness of the body in that part can be secured and increased. According to this, the body rigidity, especially the cutting insert, can be improved without changing the size of the body circumference. This improves the body rigidity of the part of the shaft opposite the cutting edge. It is possible to suppress chatter that can occur when performing machining such as diameter machining.

[0009] In the body of the cutting tool as described above, the deep seat portion includes a surface perpendicular to the axis of the screw hole. may be.

[0010] In the body of the cutting tool as described above, a shape that engages with the recess at the bottom of the cutting insert The engaging projection may be formed.

[0011] The engaging projection of the body of the cutting tool as described above is formed in a shape that protrudes from the deep seat. That's fine.

[0012] The engaging protrusion of the body of the cutting tool as described above is aligned with the center axis X extending in the longitudinal direction of the body. The cutting insert recess is formed in a triangular or trapezoidal shape in a cross section perpendicular to the cutting insert recess. The tip rotation part prevents the cutting insert from rotating around the axis of the screw hole by contacting the tip rotation part. It may have a restraining portion.

[0013] In the body of the cutting tool as described above, the tip-side rotation inhibiting portion is formed at the tip of the body. It may be done.

[0014] In the body of the cutting tool as described above, the shallow seat portion becomes narrower as it approaches the base end of the body. The recess may be formed so as to become gradually shallower while inclining.

[0015] In the body of the cutting tool as described above, the shallow seat portion becomes narrower as it approaches the base end of the body. The depth may be formed to become shallower in stages.

[0016] The body of the cutting tool as described above may be provided with a plurality of receiving portions.

[0017] In the body of the cutting tool as described above, the receiving portion is at least located at a tip end of the screw hole. Alternatively, the screw holes may be provided in both the region closer to the base end and the region closer to the base end than the screw holes.

[0018] In the body of the cutting tool as described above, a flat surface is formed on the peripheral surface of the base end side, With respect to a Y axis perpendicular to the flat surface, or perpendicular to the Y axis and in the longitudinal direction of the body The deep seat portion may be inclined with respect to a Z axis that is also perpendicular to the extending central axis X.

[0019] In the cutting tool body as described above, the rotation of the workpiece relative to the cutting edge during cutting A first reference plane is parallel to the direction of the axis of the body and includes a central axis X extending in the longitudinal direction of the body. The deep seat portion may be inclined.

[0020] In the body of the cutting tool as described above, the deep seat is When the rotation restricting portion of the engagement protrusion is engaged with the rotation restricting portion of the outer circumferential surface of the body, The thickness of the vertical direction up to the part located vertically below the part may be inclined in a direction increasing. .

[0021] Another aspect of the present invention is a cutting insert that is detachable from the body as described above, a cutting edge provided at a tip portion of the cutting insert; A screw hole through which the threaded part of the fixing screw passes, Equipped with The axis of the screw hole and the peripheral side portion of the cutting insert are parallel to each other, When viewed along a central axis X extending in the longitudinal direction of the cutting insert, the cutting edge A cutting insert that forms an arbitrary angle in one direction with respect to the axis of the hole.

[0022] In the cutting insert as described above, the cutting edge is formed when the cutting insert is attached to the body. When viewed from the tip along the central axis X, the It is also possible.

[0023] In the cutting insert as described above, the top part located on the opposite side to the bottom part is perpendicular to the central axis X. It may be arcuate in straight cross section.

[0024] Yet another aspect of the present invention is a cutting insert that is detachable from an insert seat of a body. So, a cutting edge provided at a tip portion of the cutting insert; a screw hole through which a threaded portion of a fixing screw for fixing the cutting insert to the insert seat passes; , Abutting against the insert seat, formed on the bottom of the cutting insert facing the insert seat A contact portion; a top portion located opposite the bottom portion and having an arc-shaped cross section; a base portion that is thinner than the maximum thickness of the bottom and top; Equipped with The cutting insert has an inner surface which forms an insert seat at a base end portion of the peripheral side portion thereof. This cutting insert has a contact portion that contacts the wall surface. [Brief explanation of the drawings]

[0025] [Figure 1] FIG. 2 is a perspective view showing the tip end side of the body of the cutting tool and the cutting insert according to the embodiment of the present invention. [Figure 2] FIG. 2 is a perspective view showing the tip end side of the body. [Figure 3] FIG. 10 is a view showing the tip end side of the body as viewed toward the insert seat. [Figure 4] 4 is a view showing a state in which a cutting insert is attached to an insert seat of the body shown in FIG. 3. FIG. [Figure 5] FIG. 2 is a view of the cutting tool as viewed from the tip end side along the central axis of the body. [Figure 6] 3A and 3B are diagrams illustrating a point of force, a fulcrum, and a point of action of a force acting on a cutting insert during cutting. [Figure 7] 5 is a view of the cutting tool shown in FIG. 4, viewed from below in FIG. 4, parallel to the deep seat portion of the insert seat. [Figure 8] FIG. 10 is a perspective view illustrating a contact portion formed at the bottom of the cutting insert. [Figure 9] FIG. 10 is a perspective view illustrating a receiving portion formed in an insert seat of the body. [Figure 10]FIG. 1A is a schematic diagram illustrating the thickness of the body, and FIG. 1B is a diagram of the tip side of the body. [Figure 11] FIG. 1A is a perspective view of a cutting insert as viewed from the bottom side, and FIG. 1B is a perspective view of a tip end side of a body. [Figure 12] FIG. 1 is a perspective view showing an entire cutting tool. [Figure 13] FIG. 2 is a view of the body viewed from the tip end side along its central axis. [Figure 14] FIG. 10 is a view showing the insert seat of the body as viewed along the Y axis. [Figure 15] FIG. 10 is a view showing the insert seat of the body as viewed along the axis of the screw hole. [Figure 16] 10A and 10B are perspective views showing examples of shapes of an engaging protrusion and a wall portion of an insert seat. [Figure 17] 17 is an enlarged view of the engaging protrusion and its periphery shown in FIG. 16. FIG. [Figure 18] 17 is an enlarged view of the wall portion and its surroundings shown in FIG. 16. FIG. [Figure 19] FIG. 2 is an enlarged perspective view showing the periphery of a wall portion on the base end side of the insert seat. [Figure 20] FIG. 1 is a view of the cutting insert as viewed from the top side (cylindrical outer peripheral surface side) along the axis of the screw hole. [Figure 21] FIG. 2 is a view of the cutting insert as seen from the tip end side. [Figure 22] FIG. 1 is a view of the cutting insert viewed from the bottom side along the axis of the screw hole. [Figure 23] FIG. 21 is a view of the cutting tool shown in FIG. 20 as seen from above in FIG. 20. [Figure 24] FIG. 21 is a view of the cutting tool shown in FIG. 20 as seen from below in FIG. 20. [Figure 25] FIG. 2 is a perspective view of the cutting insert, showing the top side thereof, as viewed from the tip end side. DETAILED DESCRIPTION OF THE INVENTION

[0026] Hereinafter, preferred embodiments of the cutting tool body and cutting insert according to the present invention will be described with reference to the drawings. The configuration will be described in detail (see FIGS. 1 to 25).

[0027] The cutting tool 10 described below is used for cutting a groove on the inner diameter end face of a workpiece 100. The tool is configured as a tool suitable for various machining processes, and includes a body 20 and an inner and a cutting insert 40 attached to the seat 22 (see FIG. 1, etc.).

[0028] For the sake of convenience, the present specification defines three directions or axes as follows: Note that what is defined here is the direction (or axis) of the cutting tool 10 alone. First, the axis parallel to the central axis 20x along the longitudinal direction of the body 20 is defined as the X axis (see FIG. 12). The Y axis is perpendicular to the X axis, and the Z axis is perpendicular to the X and Y axes (see Figure 13). The four flat surfaces (a set of parallel flat surfaces and and another set of planes perpendicular to the set of flat surfaces 202. The Z axis is perpendicular to another set of flat surfaces 202 (see FIG. 13, etc.). The portion of the cylindrical member 1 excluding the flat surface 202 is a cylindrical outer peripheral surface 203 .

[0029] The cutting tool 10 of this embodiment has a body 20 that supports the cutting insert 40 with greater rigidity. The structure has been improved with the aim of improving the rotation. The cutting edge 42 of the cutting insert 40 is brought into contact with the inner diameter end face of the workpiece 100. Considering the direction of the principal component of cutting force (see Figure 6), the cutting edge 42 on which the external force acts is the force point, and the fixed The screw 60 (threaded through the screw hole 21 ) is rotated relative to the cutting insert 40 with respect to the body 20 . If it is a fulcrum, the peripheral side 46 of the base end 40b on the opposite side to the cutting edge 42 becomes the point of action, and A reaction force acts on the body 20 from this point of action, which prevents the cutting insert 40 from rotating relative to the die 20. In this case, the amount of deflection of the cutting edge 42 during cutting is suppressed. At this point, the reaction force acting from the vicinity of the base end 40b of the cutting insert 40 is transmitted to the body 20. From this point of view, it is important to increase the distance from the fulcrum to the point of application. This is a viable measure in that it makes it easier to suppress the deflection of the force point (cutting edge 42). In this case, the body 20 and its insert 40 must be adjusted to fit the length of the cutting insert 40. The seat seat 22 must also be made longer, and this increases the reaction force acting from the vicinity of the base end 40b. Even if it is properly received, the body itself will bend, and the overall bending will have a negative impact. The cutting tool 10 of this embodiment has the following features: The cutting insert 40 can be made longer. This is based on the idea of ​​increasing the rigidity of the body 20 as a cantilever. The detailed structure of is as follows:

[0030] [body] The body 20 has a tip 20t provided with an insert seat for mounting the cutting insert 40. The insert seat 22 is provided with a screw hole 21 and a deep seat (see Figs. 3 and 4). The recess 23, the shallow seat portion 25, the wall portion 26, the engaging protrusion 27, etc. are formed (see FIG. 2, etc.).

[0031] The screw hole 21 is threaded with a fixing screw 60 for fixing the cutting insert 40 to the body 20. In this embodiment, the axis 21A of the screw hole 21 is the insert hole. The seat 22 is perpendicular to the deep seat portion 23 (or the bottom surface 23b thereof) (FIG. 8, (see FIG. 10(B) etc.)

[0032] The deep seating portion 23 is provided in a deep portion of the insert seat 22 in the axial direction of the screw hole 21A of the screw hole 21. It is a seating portion formed. A bottom surface 23b perpendicular to the axis 21A of the screw hole 21 is formed in the deep seating portion 23. The bottom surface 23b includes a flat surface, but does not have to be flush. In the present embodiment, a countersink 23c is provided around the screw hole 21, and the countersink 23c is deeper than the surroundings (see FIGS. 2, 9, 14, 19, etc.). The countersink 23c is the deepest part along the axial direction of the screw hole 21A in the insert seat 22.

[0033] The receiving portion 24 is a portion that contacts the bottom portion 43 of the cutting insert 40 attached to the insert seat 22 and directly supports the cutting insert 40. The receiving portion 24 may be provided so as to contact the entire bottom portion 43 of the cutting insert 40, or may be provided so as to partially contact a part of the bottom portion 43. In the present embodiment, a plurality of, for example, three regions (referred to as "contact portions 44" in this specification) of the bottom portion 43 of the cutting insert 40 are opposed to a plurality of, for example, three regions, and each contact portion 44 is received, and these three regions are each made to function as the receiving portion 24 (see FIG. 11 etc.). These receiving portions 24 are arranged in both a region closer to the tip portion 20t than the screw hole 21 and a region closer to the base end portion 20b than the screw hole 21. In the body 20 of the present embodiment, two of these three receiving portions 24 are located closer to the tip portion 20t than the screw hole 21, and the remaining one is located closer to the base end portion 20b than the screw hole 21 (see FIGS. 6 to 9). Also, all of these receiving portions 24 are ​​​​​​​​​​​​​It is provided in the deep seat portion 23, not in the shallow seat portion 25 described later (see FIG. 6, etc.). The seat portion 23 has portions with different depths, that is, in this embodiment, three levels of depth. Only one of these is called the shallow seat portion 25, and the two are collectively called the deep seat portion 23.

[0034] The shallow seat portion 25 is located in the insert seat 22 closer to the base end portion 20b than the deep seat portion 23. The shallow seat portion 25 is a portion where the depth in the direction of the axis 21A of the screw hole 21 is smaller than that of the deep seat portion 23. (See FIGS. 10 and 11.) The body 20 of this embodiment, in which the portion has a shallow seat surface and the shallow seat portion 25, is The thickness of the portion of the seat 22 (the portion near the base end 20b) is greater than that of the portion near the tip end 20t. (See the part indicated by the double arrow with the symbol T in Figure 10(A)) In other words, the insert seat 22 is formed by removing the body 20 during the manufacturing process. The volume removed when inserting is reduced, and the cross-sectional area of ​​the body 20 is increased. The thickness of the body 20 at the base end 20b increases as it approaches the base end 20b. By increasing the size of the body 20, the rigidity of the body 20 as a cantilever beam is improved, and the bending resistance is reduced. The shallow seat portion 25 is configured to be Alternatively, the base end 20b of the body 20 may be formed so as to gradually become shallower while inclining. The depth may be formed so as to become shallower in stages as it approaches the depth.

[0035] The wall portion 26 is composed of an inner wall surface 26a that rises from the insert seat 22 in the direction of the screw shaft 21A. (See Figures 15 and 16.) The body 20 has a substantially circular cross section. In the present embodiment, in which the wall portion 22 is formed, most of the wall portion 26 is formed around the shallow seat portion 25. (See FIGS. 6 and 7, etc.) The wall portion 26 is formed to match the shape of the base end portion 40b of the cutting insert 40. The base end 40b of the cutting insert 40 is formed within the area surrounded by the inner wall surface 26a. (See Figs. 6 and 7, etc.) The inner wall surface 26a is also designed to accommodate the cutting insert. The circumferential side portion 46 of the insert 40 is formed to have line contact or point contact at two points. In this specification, these portions provided at two locations on the inner wall surface 26a are referred to as This is called the "base end rotation restraining portion" and is indicated in Figure 6 by a small circle along with the symbol 26s.

[0036] As described above, the base end rotation inhibiting portion 26s contacts the peripheral side portion 46 of the cutting insert 40. This restricts the rotation of the cutting insert 40 around the axis 21A of the screw hole 21. The cutting insert 40 is positioned to prevent the cutting insert 40 from moving toward the base end 20b. In this embodiment, the two base end side rotation inhibiting portions 26s are provided at the cutting edge. The proximal end 40b of the insert 40 is positioned between the two. The base end rotation inhibiting portion 26s located at the upper side in the cutting insert 42 prevents the cutting edge 42 from rotating during machining. When an external force acts on the cutter 40, a reaction force acts from the base end 40b on the opposite side of the cutting edge 42. When the base end side rotation inhibiting portion 26s receives the reaction force in this way, As described above, the body 20 of this embodiment, which has an increased thickness, is able to suppress deflection while absorbing reaction force. When viewed along the axis 21A of the screw hole 21, When viewed along the Y-axis, these two base end rotation inhibiting portions 26s overlap with the deep seat portion 23. In other words, the shallow seat portion 25 is located at a position where these base end side rotation inhibiting portions 26s It can be said that the part is formed in the part containing the The base end rotation inhibiting portion 26s is located at the edge of the inner wall surface 26a of the wall portion 26, and The support 40 is provided so as to come into point contact with the peripheral side portion 46 of the support 40 (see FIG. 18).

[0037] The engaging protrusion 27 is attached to the insert seat 22 at the tip 20t of the body 20. A part of the cutting insert 40 (specifically, the bottom part of the cutting insert 40 as described later) The recess 43c of the deep seat 23 is formed to protrude from the bottom surface 23b of the deep seat 23 so as to engage with the recess 43c of the deep seat 23. The engaging protrusion 27 of this embodiment is formed in a YZ cross section (along the X axis) (see FIGS. 11 to 17). The vertical cross section is formed in a triangular or trapezoidal shape (see Figures 13 and 17). ), and the specific shape thereof is not particularly limited. The recess 43c of the insert 40 is formed to have point contact or line contact with a part of the recess 43c. In the detailed description, the engaging protrusion 27 comes into contact with a part of the recess 43c of the cutting insert 40. This part is called the "tip side rotation prevention part" and is shown in Figure 5 with a small circle and symbol 27s. There are.

[0038] The tip-side rotation inhibiting portion 27s is in contact with a part of the recess 43c of the cutting insert 40 as described above. By contacting the cutting insert 40, the cutting insert 40 acts as a rotation stopper around the axis 21A of the screw hole 21. It functions as a "rotation stopper" (see Figure 5). The tip-side rotation inhibiting portion 27s is provided in the vicinity of the screw hole 21. The cutting insert 40 is used as a fulcrum for the rotation of the cutting insert 40. 40 (see FIG. 6). When an external force is applied to the cutting insert 40 from the body 2 around the screw shaft 21A, By increasing the contact area between the screw shaft 21A and the cutting insert 40, This tip side circuit has the function of increasing the supporting force (distributing the reaction force at the fulcrum to multiple points). This is performed by the roll prevention unit 27s.

[0039] The height of the tip-side rotation inhibiting portion 27s from the deep seat portion 23 (in other words, the height in the direction of the screw shaft 21A) The distance Y between the tip side rotation inhibiting portion 27s and the bottom surface 23b of the deep seat portion 23 27 Yes, it is possible It is preferable that the rotational speed of the front end side rotation inhibiting portion 27s is low (small) (see FIG. 5, etc.). Even if the force is the same, the height 27 If the pressure is high (large), the engaging protrusion 27 is deformed accordingly. Therefore, the force acting on the engaging protrusion 27 is increased while suppressing deformation of the engaging protrusion 27. From the viewpoint of supporting the cutting insert 40 at the stopper portion 27s, The stopper portion 27s is as close as possible to the bottom surface 23b (i.e., the height Y 27 It is preferable that the temperature is low.

[0040] In the body 20 of the cutting tool as described above, the deep seat portion 23 is When viewed from the end 20t, it is tilted within a predetermined range (angle θ) (see FIG. 13). Specifically, the deep seat portion 23 is inclined at an angle θ with respect to the Z axis. The tilt direction is counterclockwise in FIG. 7, the thickness below the tip side rotation inhibiting portion 27s in the vertical direction (in other words, the tip side rotation inhibiting portion 27s of the outer circumferential surface of the body 20 in the Z-axis direction of the tip-side rotation inhibiting portion 27s This refers to the vertical thickness up to the part located directly below along the Z 27 (shown in Fig. 5 and Fig. 13) Thickness Z directly below 27 When the force increases, the direction of the principal force in the engaging protrusion 27 (in this example, Z As a result, the support volume in the axial direction is increased, and the support rigidity is improved. The cutting insert 40 can be supported by the tip-side rotation inhibiting portion 27s while further suppressing the rotation. In this embodiment, θ is set to 14°, but it can also be set to a larger angle. From the viewpoint of the support rigidity of the engaging protrusion 27, θ=27° may be acceptable. The angle θ is preferably within the range of 14 to 27°. The rotation direction of the workpiece 100 relative to the cutting edge 42 during cutting (in this embodiment, the Z axis) A plane (hereinafter referred to as "plane") parallel to the direction of the arrow A and including the central axis 20x of the body 20 If a "first reference surface" (referred to as a "first reference surface" and indicated by the symbol S in FIG. 13) is assumed, the deep seat portion 23 can also be described as being inclined at a predetermined angle θ with respect to the first reference plane S (FIG. 5 , see Figure 13).

[0041] [Cutting insert] The cutting insert 40 includes a screw hole 41, a cutting edge 42, a bottom portion 43, a recess 43c, and an abutment portion 44. , a peripheral side portion 46, a contact portion 47, a top portion 48, etc., and the insert seat of the body 20 as described above. 22 (see Figs. 8, 11, 20 to 25, etc.). The sheet 40 is formed, for example, by compressing and molding powder and then sintering the powder.

[0042] The screw hole 41 is formed so that the threaded portion 61 of the fixing screw 60 passes through along the screw axis 41A of the screw hole 41. (See Figure 8, etc.)

[0043] The cutting edge 42 is formed at a tip portion 40t of the cutting insert 40 (see FIG. 20, etc.). In the cutting insert 40 of this embodiment, the cutting edge 42 extends from the tip portion 40t When viewed from the side, the bottom 43 or the screw shaft 41A is tilted at an arbitrary angle in one direction. The cutting edge 42 in this inclined state is formed in the above-mentioned manner (see FIG. 21). The cutting insert is placed in the insert seat 22 whose deep seat portion 23 is inclined at an angle θ with respect to the first reference plane S. When the port 40 is attached, it is positioned approximately along the Y axis (in other words, approximately (Almost vertical state) (see Figures 4 and 5, etc.)

[0044] The bottom portion 43 is a side of the cutting insert 40 facing the insert seat 22 of the body 20. (See FIG. 22, etc.) The bottom 43 is a portion extending from the body 20 toward the tip 20t. The protruding portion (in other words, the portion from the recess 43c to the tip portion 40t, which will be described later, is denoted by the reference numeral 4 3t) is recessed in an arc along the cylindrical surface, and is particularly suitable for grooving the end face. (See FIG. 11, etc.) The bottom 43 has a flat surface 43f around the screw hole 41. (See FIGS. 11 and 22, etc.) In the portion closer to the base end portion 40b than the flat surface 43f, 11, 23, etc., a protruding portion 43p that constitutes one of the contact portions 44 is provided. ) The bottom 43 is also formed with a recess 43c (see FIG. 22, etc.).

[0045] The recess 43c is formed to fit the engaging protrusion 27 of the body 20 (see FIG. 22, etc.). When the cutting insert 40 is attached to the insert seat 22 of the body 20, the engaging protrusion 27 The tip-side rotation inhibiting portion 27s is fitted into the recess 43c and comes into point contact with the recess 43c or Line contact (see Figure 5, etc.).

[0046] The abutment portion 44 is formed on the bottom portion 43 as a portion that abuts against the insert seat 22 of the body 20. In this embodiment, the body 20 has a counterbore 23c, which divides the body 20 into two parts. The two regions corresponding to the receiving portions 24 and the end surface region of the protruding portion 43p form a total of three contact portions 44. (See Figures 6 and 8, etc.)

[0047] The top portion 48 is located on the opposite side of the bottom portion 43 and is a portion including an outer peripheral surface having an arc-shaped cross section ( (See FIG. 21, etc.) The outer peripheral surface constituting the top portion 48 defines the cutting insert 40 at the tip portion 40t. When viewed from the X-axis (or in the YZ section perpendicular to the X-axis), it has a cylindrical shape. The shape is suitable for groove machining of the end face (see Figure 21). The surrounding area of ​​41 has been scraped to make it flat (in the figure, the scraped shape is The flat surface formed is shown as 48f.

[0048] The peripheral side portion 46 is the portion of the side wall formed between the top portion 48 and the bottom portion 43 (FIG. 23, FIG. 24, etc.). In the peripheral side portion 46, the base end portion 40b of the cutting insert 40 A contact portion 47 that contacts the inner wall surface 26a of the body 20 is provided at the portion (see FIG. 6, etc.). In this embodiment, the peripheral side portion 46 is formed parallel to the axis 41A of the screw hole 41. However, the peripheral side portion 46 does not have to be parallel to the axis 41A, and may be inclined relative to the axis 41A depending on the portion. From the viewpoint of reducing manufacturing costs, it is preferable to change the angle of the Preferably, side 46 is parallel to axis 41A or at a constant angle thereto.

[0049] The contact portion 47 is provided at two locations on the inner wall surface 26a of the body 20. s (see FIG. 6, etc.). The cutting insert 40 has a base end 40b. By contacting the inner wall surface 26a of the body 20 through these contact portions 47, When an external force is applied from the cutting edge 42, the reaction force is received by the body 20 and supported. It has been done.

[0050] In addition, in the cutting insert 40 of this embodiment, the bottom portion 43 is formed in the deep seat portion 23 of the body 20 and and shallow seat portion 25, and its position in the Y-axis direction is adjusted from tip end portion 40t to base end portion 40b. The position (depth) of the grooves is changed (see Fig. 7, Fig. 25, etc.). The base end 20b of the cutting insert 40 in this state is aligned along the screw axis A between the bottom 43 and the top 48. The shape has a portion thinner than the maximum thickness in the direction of the arrow (see Figure 11, etc.). The ratio of the thickness of the thin portion to the thickness of the cut portion is not particularly limited. In the insert 40, the thickness is 80% or less. The proximal end 40b is provided on a peripheral side portion 46 of the proximal end 40b having a shape similar to that of the proximal end 40a (see FIG. 6).

[0051] According to the cutting tool 10 of this embodiment as described above, the base end 20 of the body 20 The depth of the seat at the portion b is shallower than the portion of the insert seat 22 where the receiving portion 24 is located. The shallow seat portion 25 is formed as shown in FIG. 1, and the thickness of the body 20 at that portion is increased. The rigidity, especially the cutting edge 42 of the cutting insert 40, is improved without changing the size of the outer circumference of the cutting insert 40. This improves the body rigidity at the opposite side of the groove. This makes it possible to suppress chatter that can occur during machining such as milling and internal machining.

[0052] It is possible to form a shallow seat portion 25 having a shallow seat depth without changing the outer periphery size of the body 20. If this is the case, the thickness of the base end portion 40b of the cutting insert 40 will be reduced accordingly. In the embodiment, taking into consideration the point of force, the fulcrum, and the point of action, the base end side rotation inhibiting portion is provided at the shallow seat portion 25. 26s and the contact portion 47 are arranged, and the tip side rotation inhibiting portion 2 of the engaging protrusion 27 7s, a fulcrum (as described above, in this specification, the body 2 0) By assisting the force supporting the cutting insert 40, it is possible to reduce the amount of deflection of the cutting edge. It states that:

[0053] As described above, in the cutting tool 10 of this embodiment, the tip portion 101 extends along the central axis 20x. When viewed from the side of the seat 20t, the deep seat portion 23 is inclined within a predetermined range (angle θ). As a result, an angle is formed between the direction of the insert seat 22, which is the insert fastening surface, and the direction of the cutting edge 42. By attaching the engaging protrusion 27, the principal component of force in the engaging protrusion 27 (in this example, the Z-axis direction) This increases the support volume (in the vertical direction) and improves the support rigidity. By angling the direction of the insert fastening surface and the direction of the cutting edge 42 in this way, 22 is gradually made shallower, and the main component of resistance (main In this example, the force acting in the Z-axis direction is applied to the seat of the insert seat 22 perpendicular to the screw axis 21A. This also brings about the advantage that the support can be achieved by the frictional force of the surface.

[0054] The above-described embodiment is an example of a preferred embodiment of the present invention, but is not intended to be limiting. Various modifications can be made without departing from the spirit of the present invention. In this embodiment, the portions that become the seating surfaces of the deep seat portion 23 and the shallow seat portion 25 of the insert seat 22 are mainly Although an example in which the surface is a flat surface perpendicular to the screw shaft 21A has been shown (FIGS. 9 to 11, etc.), this is a preferred example. Although not shown in the figure, the seating surfaces of the deep seat portion 23 and the shallow seat portion 25 are V-shaped. The surface may be other than a flat surface, such as a flat surface.

[0055] The cutting tool 10 of this embodiment is attached to a lathe, for example, and is used to cut a rotating workpiece. By pressing the cutting edge 42 against the workpiece 100, a donut-shaped groove is formed on the end surface of the workpiece 100. However, this is only one example. In addition to turning tools, the present invention can also be applied to turning tools such as trepanning cutters. [Industrial Applicability]

[0056] The present invention relates to various cutting tools, including face grooving tools, and the bodies of such cutting tools. It is suitable for application to cutting inserts. [Explanation of symbols]

[0057] 10…Cutting tools 20...Body 20b...Proximal end 201...Proximal side circumferential surface 202…Flat surface 20t...Tip 203...Cylindrical outer surface 20x(X)…Center axis 21...Screw hole 21A...Threaded hole axis 22...insert seat 23…Deep seat part 23b...Bottom of deep seat 23c...recessed 24...Receiving part 25...Shallow seat 26...Wall part 26a...Inner wall surface 26s...Base end rotation prevention part 27…Engagement convex portion 27s...Tip side rotation prevention part 40...Cutting insert 40b…Proximal end 40t...tip 41...Screw hole 41A…axis 42...Cutting edge 43...bottom 43c...recess 43f...Flat surface around the screw hole 43p…Protrusion 43t: A portion of the bottom 43 that protrudes from the body 20 toward the tip 20t. 44...Contact part 46...Side part 47...Contact part 48…Top 48f...Flat surface around the screw hole 60...Fixing screw 61...Threaded part 100…Work material S...First reference plane T: Vertical thickness of the body Y 27 ...Height of the tip-side rotation inhibiting portion 27s from the deep seat portion 23 Z 27 ...From the tip side rotation inhibiting portion 27s to the outer circumferential surface of the body 20, the tip side rotation inhibiting portion 2 Vertical thickness up to the part located directly below 7s along the Z-axis

Claims

1. A cutting insert that is detachable from an insert seat of a body, a cutting edge provided only at a tip portion of the cutting insert; A screw hole through which the threaded part of the fixing screw passes, a plurality of abutment portions formed on a bottom portion of the cutting insert facing the insert seat, the abutment portions abutting the insert seat; Equipped with a contact portion at a portion of a peripheral side of the cutting insert at a base end of the body, the contact portion being in contact with a wall portion having at least two base end side rotation inhibiting portions provided on an inner wall surface of the body that constitutes the insert seat; The axis of the screw hole and the peripheral side portion of the cutting insert are parallel to each other, When the cutting insert is viewed from the tip, the cutting edge is inclined in one direction at an arbitrary angle with respect to the axis of the screw hole.

2. 2. The cutting insert according to claim 1, wherein, when viewed from the tip end portion with the cutting insert attached to the body, the cutting edge is parallel to a rotation direction of a workpiece relative to the cutting edge during cutting and perpendicular to a first reference plane including a central axis X extending in a longitudinal direction of the body.

3. The cutting insert according to claim 2 , wherein at least a portion of a top portion of the cutting insert located opposite to a bottom portion facing the insert seat is arc-shaped in a cross section perpendicular to the central axis X.

4. A cutting insert that is detachable from an insert seat of a body, a cutting edge provided only at a tip portion of the cutting insert; a screw hole through which a threaded portion of a fixing screw for fixing the cutting insert to the insert seat passes; a plurality of abutment portions formed on a bottom portion of the cutting insert facing the insert seat, the abutment portions abutting the insert seat; a top portion located opposite the bottom portion and having an arc-shaped cross section; a base portion that is thinner than the maximum thickness of the bottom and the top; Equipped with A cutting insert having a contact portion at the base end portion of the peripheral side portion of the cutting insert that abuts against a wall portion having at least two base end rotation inhibiting portions provided on an inner wall surface of the body that constitutes the insert seat.

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