Cutting unit, cutting tool, tool rest, and method for manufacturing machined product

Abstract

The present invention pertains to stably holding a holder using a holding block and improving workability with respect to the work of attaching the holder onto the holding block. A clamp member has a pressing unit that, in a state of being interposed between one inner surface of a groove of the holding block and the top surface of the holder, presses the holder to the other inner surface side of the groove. The pressing unit has a first projection that abuts a first inclined surface of a first notch section of the holder, and a second projection that is spaced apart from the first projection and that abuts a second inclined surface of a second notch section of the holder.

Description

[Technical Field]

[0001] The present disclosure relates to a cutting tool used in cutting a workpiece, a cutting tool, a tool rest, and a method for manufacturing a machined product. [Background technology]

[0002] A cutting unit that can be attached to a machine tool is used when cutting a workpiece made of metal or the like. The cutting unit described in Patent Document 1 includes a holder (a part of the cutting tool excluding the tip in Patent Document 1) and a cutting blade located at the tip of the holder and on the side of a first side surface. The cutting unit described in Patent Document 1 includes a holding block (referred to as a cutting tool holder in Patent Document 1) having a groove (referred to as a recessed groove in Patent Document 1) for holding the holder, and a clamp member for fixing the holder to the holding block.

[0003] The clamp member has two tightening bolts threadedly engaged with the holding block and presser pieces connected to the tips of the two tightening bolts. The two presser pieces are interposed between one inner surface of the groove in the holding block and the top surface of the holder, and press the holder toward the other inner surface of the groove in the holding block. The first of the two presser pieces abuts against the inclined surface of a first of two notches (referred to as "notches" in Patent Document 1) in the holder. The second of the two presser pieces abuts against the inclined surface of a second of two notches in the holder. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Utility Model Publication No. 02-048164 Summary of the Invention

[0005] The cutting unit according to the present disclosure includes a holder, a cutting blade, a holding block, and a clamping member. The holder has a rectangular prism shape extending from its front end to its rear end, and has a front end surface located on the front end side, an upper surface extending from the front end surface toward the rear end, a lower surface located opposite the upper surface, a first side surface located between the upper and lower surfaces and extending from the front end surface toward the rear end, and a second side surface located opposite the first side surface. The cutting blade is located on the front end and on the side of the first side surface. The holding block has a groove for holding the holder. The clamping member is located in the holding block and has a pressing portion interposed between one inner surface of the groove and a main body portion, pressing the holder toward the other inner surface of the groove, thereby fixing the holder to the holding block. The upper surface has a first notch with a first inclined surface that moves away from the lower surface as it approaches the rear end, and a second notch that is located closer to the rear end than the first notch and has a second inclined surface that moves away from the lower surface as it approaches the rear end. The pressing portion has a first protrusion that abuts against the first inclined surface, and a second protrusion that is spaced from the first protrusion and abuts against the second inclined surface.

[0006] The cutting tool according to the present disclosure includes a holder and a cutting blade. The holder has a rectangular prism shape extending from the front end to the rear end, and has a front end surface located on the front end side, an upper surface extending from the front end surface toward the rear end, a lower surface located opposite the upper surface, a first side surface located between the upper and lower surfaces and extending from the front end surface toward the rear end, and a second side surface located opposite the first side surface. The cutting blade is located at the front end and on the side of the first side surface. The upper surface has a first notch and a second notch located closer to the rear end than the first notch. The first notch has a first inclined surface that moves away from the lower surface as it approaches the rear end, and is open to the first and second side surfaces. The second notch has a second inclined surface that moves away from the lower surface as it approaches the rear end, and is open to the first and second side surfaces.

[0007] A tool rest according to the present disclosure is a tool rest to which a cutting tool according to the present disclosure can be attached, and includes a holding block and a clamping member. The holding block has a groove for holding a holder. The clamping member is located on the holding block and has a pressing portion interposed between one inner surface and the top surface of the groove, pressing the holder toward the other inner surface of the groove, thereby fixing the holder to the holding block. The pressing portion has a first protruding portion that abuts against the first inclined surface and a second protruding portion that is spaced from the first protruding portion and abuts against the second inclined surface. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 1 is a schematic perspective view of a cutting unit according to an embodiment of the present disclosure. [Figure 2] FIG. 2 is a schematic enlarged side view of the cutting unit shown in FIG. [Figure 3] FIG. 2 is a schematic top view of the cutting unit shown in FIG. [Figure 4] FIG. 1 is a schematic perspective view of a cutting tool according to an embodiment of the present disclosure. [Figure 5] FIG. 5 is a schematic top view of a portion of the cutting tool shown in FIG. 4. [Figure 6] FIG. 5 is a schematic side view of the cutting tool shown in FIG. 4. [Figure 7] FIG. 5 is a schematic bottom view of the cutting tool shown in FIG. 4. [Figure 8] FIG. 5 is a schematic enlarged view of the cutting tool shown in FIG. 4, viewed from the tip. [Figure 9] FIG. 3 is a schematic enlarged cross-sectional view taken along line IX-IX in FIG. 2. [Figure 10] FIG. 7 is a schematic enlarged view taken along line XX in FIG. 6. [Figure 11] FIG. 7 is a schematic enlarged view taken along line XI-XI in FIG. 6. [Figure 12] FIG. 2 is a schematic perspective view showing a clamp member and a plurality of fixing bolts. [Figure 13] FIG. 2 is a schematic perspective view showing a clamp member and a plurality of fixing bolts. [Figure 14]FIG. 2 is a schematic cross-sectional view taken along the longitudinal direction of the clamp member. [Figure 15] FIG. 4 is a schematic cross-sectional view taken along line XV-XV in FIG. [Figure 16] 1A to 1C are schematic diagrams illustrating a method for manufacturing a machined product according to an embodiment of the present disclosure. [Figure 17] 1A to 1C are schematic diagrams illustrating a method for manufacturing a machined product according to an embodiment of the present disclosure. [Figure 18] 1A to 1C are schematic diagrams illustrating a method for manufacturing a machined product according to an embodiment of the present disclosure. DETAILED DESCRIPTION OF THE INVENTION

[0009] The cutting unit described in Patent Document 1 has two independent pressure pieces, and the pressing force of the first pressure piece against the first notch of the holder and the pressing force of the second pressure piece against the second notch of the holder are adjusted separately. This can result in large variations in the pressing force of the first pressure piece and the pressing force of the second pressure piece. This can result in concentrated loads on one pressure piece and one tightening bolt, potentially reducing the durability of the cutting unit. One pressure piece can also serve as a fulcrum, potentially causing the holder to shift position. To address these concerns, it is necessary to precisely adjust the tightening forces of the two tightening bolts to reduce variations in the pressing force of the first pressure piece and the pressing force of the second pressure piece. As a result, the cutting unit described in Patent Document 1 tends to require complicated installation of the holder to the retaining block.

[0010] Therefore, there has been a demand for the development of a cutting unit that can improve the workability of attaching the holder to the holding block while allowing the holder to be stably held by the holding block.

[0011] According to one aspect of the present disclosure, the holder can be stably held by the holding block while improving the workability of attaching the holder to the holding block.

[0012] Hereinafter, a cutting tool and a method for manufacturing a machined product according to an embodiment of the present disclosure will be described in detail with reference to the drawings. However, for the sake of convenience, the drawings referred to below show only the components necessary for explaining the embodiment in a simplified form. Therefore, a cutting unit according to an embodiment of the present disclosure may include any components not shown in the drawings referred to. The dimensions of the components in the drawings do not faithfully represent the actual dimensions of the components and the dimensional ratios of each member.

[0013] In this disclosure, the following description is based on an orthogonal coordinate system, XYZ, defined by three mutually orthogonal directions. The X direction refers to the front-to-rear direction, with one side of the X direction being the front side or forward direction, and the other side of the X direction being the rear side or backward direction. The Y direction refers to the left-to-right direction, with one side of the Y direction being the left side or leftward direction, and the other side of the Y direction being the right side or rightward direction. The Z direction refers to the up-down direction, with one side of the Z direction being the upper side or upward direction, and the other side of the Z direction being the lower side or downward direction. In addition, in this disclosure, "orthogonal" does not necessarily mean strictly orthogonal, but rather means allowing for an error of about ±5 degrees. "Parallel" does not necessarily mean strictly parallel, but rather means allowing for an error of about ±5 degrees.

[0014] In the drawings, "FF" indicates the forward direction, "FR" indicates the rearward direction, "L" indicates the leftward direction, "R" indicates the rightward direction, "U" indicates the upward direction, and "D" indicates the downward direction.

[0015] <Cutting unit 10> A cutting unit 10 according to an embodiment of the present disclosure will be described with reference to FIGS. 1 to 14. FIG. 1 is a schematic perspective view of the cutting unit 10 according to an embodiment of the present disclosure. FIG. 2 is a schematic enlarged side view of the cutting unit 10 shown in FIG. 1. FIG. 3 is a schematic top view of the cutting unit 10 shown in FIG. 1. FIG. 4 is a schematic perspective view of a cutting tool 12 according to an embodiment of the present disclosure. FIG. 5 is a schematic top view of a portion of the cutting tool 12 shown in FIG. 4. FIG. 6 is a schematic side view of the cutting tool 12 shown in FIG. 4. FIG. 7 is a schematic bottom view of the cutting tool 12 shown in FIG. 4. FIG. 8 is a schematic enlarged view of the cutting tool 12 shown in FIG. 4, as viewed from the tip. FIG. 9 is a schematic enlarged cross-sectional view taken along line IX-IX in FIG. 2. FIG. 10 is a schematic enlarged view taken along line XX in FIG. 6. FIG. 11 is a schematic enlarged view taken along line XI-XI in FIG. 6. 12 and 13 are schematic perspective views showing the clamp member 48 and the multiple fixing bolts 50, viewed from different directions. XIVA in Fig. 14 is a schematic cross-sectional view taken along line XIVA-XIVA in Fig. 12. XIVB in Fig. 14 is a schematic cross-sectional view taken along line XIVB-XIVB in Fig. 12. Fig. 15 is a schematic cross-sectional view taken along line XV-XV in Fig. 3.

[0016] As shown in the examples of FIGS. 1 to 3, a cutting unit 10 according to an embodiment of the present disclosure is a unit used for cutting a workpiece W (see FIG. 16). Cutting of the workpiece W includes external diameter machining, grooving, cut-off, and the like. The cutting unit 10 may also include a cutting tool 12 for cutting the workpiece W, and a tool rest 14 to which the cutting tool 12 can be attached.

[0017] 4 to 7, the cutting tool 12 may include a holder 16 attached to a tool post 14, a cutting insert 18 held by the holder 16, and a clamp screw 20 that fixes the cutting insert 18 to the holder 16. The holder 16 may have a rectangular prism shape extending along the X direction from a front end 16a to a rear end 16b. The longitudinal direction of the holder 16 may be the X direction.

[0018] In the present disclosure, the holder 16 being rectangular prism-shaped does not necessarily mean that the holder 16 is strictly rectangular prism-shaped, but also means that the holder 16 can be visually recognized as being generally rectangular prism-shaped overall by including a rectangular prism-shaped main body 16m. One end of the main body 16m of the holder 16 may be located closer to the rear end 16b than the front end 16a of the holder 16. The other end of the main body 16m of the holder 16 may be coincident with the rear end 16b of the holder 16. The main body 16m held by the tool post is also called a shank.

[0019] 4 to 8 , the holder 16 may have a leading end surface 22 located on the leading end 16 a side and a rear end surface 24 located on the opposite side of the leading end surface 22. The leading end surface 22 of the holder 16 is not limited to a single flat surface, and may include a plurality of flat surfaces and / or curved surfaces. The holder 16 may have an upper surface 26 extending in the X direction from the leading end surface 22 toward the rear end 16 b to the rear end surface 24. The holder 16 may have a lower surface 28 located on the opposite side of the upper surface 26, and the lower surface 28 may extend in the X direction from the leading end surface 22 toward the rear end 16 b to the rear end surface 24.

[0020] 4 to 6 and 8, the holder 16 may have a first side surface 30 located between the upper surface 26 and the lower surface 28, and the first side surface 30 may extend in the X direction from the tip surface 22 toward the rear end 16b to the rear end surface 24. The first side surface 30 of the holder 16 may be connected to the upper surface 26 and the lower surface 28. In the main body portion 16m of the holder 16, the first side surface 30 may be perpendicular to the lower surface 28 and the upper surface 26. Note that FIG. 6 is a front view of the first side surface 30.

[0021] The holder 16 may have a second side surface 32 located on the opposite side to the first side surface 30, and the second side surface 32 may extend in the X direction from the tip surface 22 toward the rear end 16b to the rear end surface 24. The second side surface 32 of the holder 16 may be connected to the upper surface 26 and the lower surface 28. In the main body portion 16m of the holder 16, the second side surface 32 may be perpendicular to the lower surface 28 and the upper surface 26. Note that FIG. 2 is a front view of the second side surface 32.

[0022] 4 to 6 and 8, the holder 16 may have a pocket 34 on the side of the tip 16a for holding the cutting insert 18. The pocket 34 of the holder 16 may be open to the tip surface 22, the upper surface 26, and the first side surface 30. The holder 16 may have a screw hole 36 (see FIG. 7) located on the side of the tip 16a. The screw hole 36 of the holder 16 may be open to the pocket 34 and the lower surface 28.

[0023] Examples of materials for the holder 16 include metals such as stainless steel, carbon steel, cast iron, and aluminum alloys. The length of the holder 16 may be set to, for example, 100 mm to 400 mm.

[0024] As shown in FIGS. 4 to 6 and 8 , the cutting insert 18 may be positioned in a pocket 34 of the holder 16. The cutting insert 18 may be a replaceable insert known as a throw-away insert. The cutting insert 18 may have a rectangular plate shape, or may have a shape other than a rectangular plate, such as a triangular or pentagonal plate shape. The cutting insert 18 may have a first insert surface 38, a second insert surface 40 located opposite the first insert surface 38, and a plurality of insert side surfaces 42 located between the first insert surface 38 and the second insert surface 40.

[0025] The cutting insert 18 may have a cutting edge 44 at the intersection of the first insert surface 38 and the insert side surface 42. The cutting edge 44 may be located at the tip 16a of the holder 16 and on the side of the first side surface 30. The first insert surface 38 may function as a rake surface for channeling chips. The portion of the first insert surface 38 that functions as a rake surface may be approximately parallel to the upper surface 26 of the holder 16. The insert side surface 42 may function as a clearance surface.

[0026] The cutting insert 18 may have a through hole that opens to the first insert surface 38 and the second insert surface 40. The through hole of the cutting insert 18 may be aligned with the screw hole 36 of the holder 16. The cutting insert 18 is attached to the pocket 34 of the holder 16 by threading the clamp screw 20, which is inserted through the through hole of the cutting insert 18, into the screw hole 36 of the holder 16 and tightening it.

[0027] Examples of the material of the cutting insert 18 include cemented carbide and cermet. Examples of cemented carbide compositions include WC-Co, WC-TiC-Co, and WC-TiC-TaC-Co. WC-Co is produced by adding cobalt (Co) powder to tungsten carbide (WC) and sintering the mixture. WC-TiC-Co is produced by adding titanium carbide (TiC) to WC-Co. WC-TiC-TaC-Co is produced by adding tantalum carbide (TaC) to WC-TiC-Co. Cermets are sintered composite materials in which a ceramic component is combined with a metal. Specific examples of cermets include those primarily composed of titanium compounds such as titanium carbide (TiC) and titanium nitride (TiN).

[0028] The surface of the cutting insert 18 may be coated with a film by chemical vapor deposition (CVD) or physical vapor deposition (PVD). Examples of the material for the film include titanium carbide (TiC), titanium nitride (TiN), titanium carbonitride (TiCN), and alumina (Al2O3).

[0029] The cutting tool 12 described above is composed of the holder 16 and the cutting insert 18, but a solid-type cutting tool composed of a single member may also be used.

[0030] 1 to 3, the tool post 14 according to an embodiment of the present disclosure may include a holding block 46, a clamping member 48 that secures the holder 16 to the holding block 46, and a plurality of fixing bolts 50 for attaching the clamping member 48 to the holding block 46. The holding block 46 is attached to the machining head of a lathe.

[0031] The holding block 46 may have a plurality of grooves 52 that hold (accommodate) the main body portion 16m of the holder 16, and the plurality of grooves 52 may be arranged at intervals in the Z direction. The groove 52 of the holding block 46 may extend in the X direction. Both ends of the groove 52 of the holding block 46 in the X direction may be open. The number of grooves 52 of the holding block 46 may be one.

[0032] 1 to 3 and 9, the grooves 52 of the holding block 46 may have a bottom surface 52a and a pair of inner side surfaces 52b, 52c rising from both sides of the bottom surface 52a. One inner side surface (first inner side surface) 52b of the grooves 52 of the holding block 46 may have a guide surface 52g. The guide surfaces 52g of the grooves 52 of the holding block 46 may be inclined with respect to the depth direction of each groove 52 (a direction parallel to the Y direction) so as to approach the center line 52s of the groove 52 as they approach the bottom surface 52a.

[0033] The bottom surface 52a of the groove 52 of the holding block 46 may abut against the first side surface 30 of the holder 16. The other inner surface (second inner surface) 52c of the groove 52 of the holding block 46 may abut against the lower surface 28 of the holder 16. In other words, the first side surface 30 of the holder 16 may abut against the bottom surface 52a of the groove 52 of the holding block 46. The lower surface 28 of the holder 16 may abut against the other inner surface 52c of the groove 52 of the holding block 46.

[0034] 1 to 3, the holding block 46 may have a plurality of screw holes 54 at one edge of each groove 52 for threading the fixing bolts 50. Examples of materials for the holding block 46 include metals such as stainless steel, carbon steel, and cast iron.

[0035] 1, 2, and 9, the clamp member 48 may be located on one edge of a groove 52 in the holding block 46. The clamp member 48 may be attached to one edge of the groove 52 in the holding block 46 by a plurality of fixing bolts 50. The clamp member 48 may extend in the X direction, and may have an L-shape when viewed from the X direction.

[0036] The clamp member 48 may have an attachment piece 56 as an attachment portion that can be attached to one edge of the groove 52 of the holding block 46, and the attachment piece 56 may extend in the X direction. The attachment piece 56 may have a plurality of through holes 58 (see FIG. 14 ) for inserting the fixing bolts 50 therethrough, and the plurality of through holes 58 may be arranged at intervals in the X direction. Each of the through holes 58 of the attachment piece 56 may be aligned with each of the screw holes 54 of the holding block 46.

[0037] 2 and 9, the clamp member 48 may have a pressing piece 60 as a pressing portion that presses the holder 16 toward the other inner surface (second inner surface) 52c of the groove 52 of the holding block 46. The pressing piece 60 may be interposed between one inner surface (first inner surface) 52b of the groove 52 of the holding block 46 and the top surface 26 of the holder 16, and press the holder 16 toward the other inner surface 52c of the groove 52 of the holding block 46. The pressing piece 60 may extend in the X direction, or may be provided so as to protrude from an edge of the attachment piece 56. The attachment piece 56 may protrude in the Y direction.

[0038] 9, the pressing piece 60 may have a sliding surface 60f that slides on the guide surface 52g of the groove 52 of the holding block 46. The sliding surface 60f of the pressing piece 60 may be inclined with respect to the protruding direction of the pressing piece 60 so as to approach the center line 52s of the groove 52 of the holding block 46 in the protruding direction of the pressing piece 60. Examples of materials for the clamp member 48 include metals such as stainless steel, carbon steel, and cast iron.

[0039] By threading and tightening each fixing bolt 50 inserted into each through-hole 58 of the mounting piece 56 into the screw hole 54 of the holding block 46, a wedge effect is exerted by the sliding surface 60f of the pressing piece 60 of the clamp member 48 and the guide surface 52g of the groove 52 of the holding block 46. This causes the pressing piece 60 of the clamp member 48 to press the holder 16 against the other inner surface 52c of the groove 52 of the holding block 46, thereby fixing the holder 16 to the holding block 46.

[0040] 2, 6, and 7, the lower surface 28 of the holder 16 may have a stepped portion 62 that is convexly curved toward the rear end 16b. The stepped portion 62 of the holder 16 may abut against the end surface 48e of the holding block 46. With the main body 16m of the holder 16 held in the groove 52 of the holding block 46, the holder 16 can be positioned with respect to the groove 52 of the holding block 46 by abutting the stepped portion 62 of the holder 16 against the end surface 48e of the holding block 46.

[0041] 4 to 6, the upper surface 26 of the holder 16 may have a first notch 64 located on one end side of the main body portion 16m. The first notch 64 of the holder 16 may have a first inclined surface 64f that is inclined with respect to an imaginary plane VF parallel to the lower surface 28 so as to move away from the lower surface 28 as it approaches the rear end 16b. The first notch 64 of the holder 16 may be open to the first side surface 30 and the second side surface 32.

[0042] 4 to 6, the upper surface 26 of the holder 16 may have a second notch 66 located closer to the rear end 16b than the first notch 64. The second notch 66 of the holder 16 may have a second inclined surface 66f that is inclined with respect to an imaginary plane VF parallel to the lower surface 28 so as to move away from the lower surface 28 as it approaches the rear end 16b. The second notch 66 of the holder 16 may be open to the first side surface 30 and the second side surface 32.

[0043] 5, the width B1 of the first cutout portion 64 of the holder 16 in the X direction, which is the longitudinal direction of the holder 16, may be larger on the second side surface 32 side than on the first side surface 30 side. The width B2 of the second cutout portion 66 of the holder 16 in the X direction may be larger on the second side surface 32 side than on the first side surface 30 side.

[0044] 10 and 11 , the depth D1 of the first cutout portion 64 of the holder 16 may be deeper on the second side surface 32 side than on the first side surface 30 side. The depth D2 of the second cutout portion 66 of the holder 16 may be deeper on the second side surface 32 side than on the first side surface 30 side. In a cross section perpendicular to the longitudinal direction of the holder 16, the inclination angle θ1 of the first inclined surface 64f of the first cutout portion 64 with respect to an imaginary plane VF parallel to the lower surface 28 may be larger than the inclination angle θ2 of the second inclined surface 66f of the second cutout portion 66 with respect to an imaginary plane VF parallel to the lower surface 28. The maximum value of the depth D1 of the first cutout portion 64 of the holder 16 may be larger than the maximum value of the depth D2 of the second cutout portion 66.

[0045] 12 to 14 , the pressing piece 60 may have a first protrusion 68 that abuts against the first inclined surface 64f of the first cutout 64 of the holder 16, and the first protrusion 68 may protrude in a direction perpendicular to the longitudinal direction of the clamp member 48. The first protrusion 68 of the pressing piece 60 may be located on the side of one end 48a of the clamp member 48. The first protrusion 68 of the pressing piece 60 may have a first abutment surface 68f that abuts against the first inclined surface 64f of the first cutout 64 of the holder 16.

[0046] 14 , in a cross section taken along the longitudinal direction of the clamp member 48, the width B1 of the first cutout 64 of the holder 16 may be greater than the width T1 of the first protrusion 68 of the pressing piece 60. The first inclined surface 64f of the first cutout 64 of the holder 16 may be a flat surface, and the first abutment surface 68f of the first protrusion 68 of the pressing piece 60 may be a convex curved surface. Alternatively, the first inclined surface 64f of the first cutout 64 of the holder 16 may be a convex curved surface, and the first abutment surface 68f of the first protrusion 68 of the pressing piece 60 may be a flat surface.

[0047] The pressing piece 60 may have a second protrusion 70 that abuts against the second inclined surface 66f of the second cutout 66 of the holder 16, and the second protrusion 70 may protrude in a direction perpendicular to the longitudinal direction of the clamp member 48. The second protrusion 70 of the pressing piece 60 may be positioned closer to the other end 48b of the clamp member 48 than the first protrusion 68. The second protrusion 70 of the pressing piece 60 may have a second abutment surface 70f that abuts against the second inclined surface 66f of the second cutout 66 of the holder 16.

[0048] 14 , in a cross section taken along the longitudinal direction of the clamp member 48, the width B2 of the second cutout 66 of the holder 16 may be greater than the width T2 of the second protrusion 77 of the pressing piece 60. The second inclined surface 66f of the second cutout 66 of the holder 16 may be a flat surface, and the second abutment surface 70f of the second protrusion 70 of the pressing piece 60 may be a convex curved surface. Alternatively, the second inclined surface 66f of the second cutout 66 of the holder 16 may be a convex curved surface, and the second abutment surface 70f of the second protrusion 70 of the pressing piece 60 may be a flat surface.

[0049] According to the embodiment of the present disclosure, the pressing piece 60 has a first protrusion 68 that abuts against the first inclined surface 64f of the first notch 64 of the holder 16 and a second protrusion 70 that abuts against the second inclined surface 66f of the second notch 66 of the holder 16. Therefore, the pressing force of the first protrusion 68 of the pressing piece 60 against the first notch 64 of the holder 16 and the pressing force of the second protrusion 70 of the pressing piece 60 against the second notch 66 of the holder 16 can be adjusted at the same time without adjusting them individually. As a result, the holder 16 can be easily attached to the holding block 46 while reducing variation in the pressing force of the first protrusion 68 of the pressing piece 60 and the pressing force of the second protrusion 70 of the pressing piece 60. As a result, according to the embodiment of the present disclosure, the holder 16 can be stably held by the holding block 46 while improving the workability of attaching the holder 16 to the holding block 46. In other words, the cutting tool 12 can be stably held by the tool rest 14 while improving the workability of the work of attaching the cutting tool 12 to the tool rest 14 .

[0050] When the first notch 64 and the second notch 66 of the holder 16 are open to the first side surface 30 and the second side surface 32, respectively, the first protrusion 68 and the second protrusion 70 of the pressing piece 60 can be easily brought into contact with the first inclined surface 64f of the first notch 64 and the second inclined surface 66f of the second notch 66 of the holder 16, respectively. This further improves the workability of the work of attaching the holder 16 to the holding block 46.

[0051] When the first side surface 30 of the holder 16 that is closer to the cutting edge 44 abuts against the bottom surface 52a of the groove 52 of the holding block 46, chatter vibrations that occur during cutting can be more easily absorbed by the holding block 46. This reduces chatter vibrations and improves the surface roughness of the machined surface Wf of the workpiece W (see FIGS. 17 and 18).

[0052] When the width B1 in the X direction of the first cutout portion 64 of the holder 16 is made larger on the second side surface 32 side than on the first side surface 30 side, the first protrusion 68 of the pressing piece 60 can be easily brought into contact with the first inclined surface 64f of the first cutout portion 64 of the holder 16. This can further improve the workability of the work of attaching the holder 16 to the holding block 46.

[0053] When the width B2 in the X direction of the second cutout portion 66 of the holder 16 is made larger on the second side surface 32 side than on the first side surface 30 side, the second protrusion 70 of the pressing piece 60 can be easily brought into contact with the second inclined surface 66f of the second cutout portion 66 of the holder 16. This can further improve the workability of the work of attaching the holder 16 to the holding block 46.

[0054] When the depth D1 of the first cutout portion 64 of the holder 16 is made deeper on the second side surface 32 side than on the first side surface 30 side, the first protrusion 68 of the pressing piece 60 can be easily brought into contact with the first inclined surface 64f of the first cutout portion 64 of the holder 16. This can further improve the workability of the work of attaching the holder 16 to the holding block 46.

[0055] When the depth D2 of the second cutout portion 66 of the holder 16 is made deeper on the second side surface 32 side than on the first side surface 30 side, the second protrusion 70 of the pressing piece 60 can be easily brought into contact with the second inclined surface 66f of the second cutout portion 66 of the holder 16. This can further improve the workability of the work of attaching the holder 16 to the holding block 46.

[0056] In particular, when the inclination angle θ1 of the first inclined surface 64f of the first notch 64 is larger than the inclination angle θ2 of the second inclined surface 66f of the second notch 66 in a cross section perpendicular to the longitudinal direction of the holder 16, the holder 16 can be firmly fixed to the holding block 46 at the first notch 64 close to the cutting edge 44. This makes it possible to improve the machining accuracy of the cutting process of the workpiece W.

[0057] When the maximum value of the depth D1 of the first notch 64 of the holder 16 is greater than the maximum value of the depth D2 of the second notch 66, the holder 16 can be firmly fixed to the holding block 46 at the first notch 64 close to the cutting edge 44. This makes it possible to improve the machining accuracy of the cutting process of the workpiece W.

[0058] In a cross section taken along the longitudinal direction of the clamp member 48, if the width B1 of the first notch 64 of the holder 16 is greater than the width T1 of the first protrusion 68 of the pressing piece 60, the first protrusion 68 of the pressing piece 60 can be easily brought into contact with the first inclined surface 64f of the first notch 64 of the holder 16. This further improves the workability of attaching the holder 16 to the holding block 46.

[0059] In a cross section taken along the longitudinal direction of the clamp member 48, if the width B2 of the second notch 66 of the holder 16 is greater than the width T2 of the second protrusion 77 of the pressing piece 60, the second protrusion 70 of the pressing piece 60 can be easily brought into contact with the second inclined surface 66f of the second notch 66 of the holder 16. This further improves the workability of attaching the holder 16 to the holding block 46.

[0060] When the first inclined surface 64f of the first cutout portion 64 of the holder 16 is a flat surface and the first abutment surface 68f of the first protrusion portion 68 of the pressing piece 60 is a convex curved surface, the first abutment surface 68f of the first protrusion portion 68 can be in stable surface contact with the first inclined surface 64f of the first cutout portion 64 without having to process the first cutout portion 64 and the first protrusion portion 68 under strict manufacturing conditions. This allows the manufacturing cost of the cutting unit 10 to be reduced.

[0061] When the first inclined surface 64f of the first cutout portion 64 of the holder 16 is a convex curved surface and the first abutment surface 68f of the first protrusion portion 68 of the pressing piece 60 is a flat surface, the first abutment surface 68f of the first protrusion portion 68 can be in stable surface contact with the first inclined surface 64f of the first cutout portion 64 without having to machine the first cutout portion 64 and the first protrusion portion 68 under strict manufacturing conditions. This allows the manufacturing cost of the cutting unit 10 to be reduced.

[0062] When the first inclined surface 64f of the first cutout portion 64 of the holder 16 and the first abutment surface 68f of the first protrusion 68 of the pressing piece 60 are each flat surfaces, it is necessary to ensure parallelism between the first abutment surface 68f of the first cutout portion 64 and the first inclined surface 64f of the first protrusion 68 in order to bring them into surface contact. Therefore, in the above case, it is necessary to process the first cutout portion 64 and the first protrusion 68 under strict manufacturing conditions.

[0063] When the second inclined surface 66f of the second cutout portion 66 of the holder 16 is a flat surface and the second abutment surface 70f of the second protrusion portion 70 of the pressing piece 60 is a convex curved surface, the second abutment surface 70f of the second protrusion portion 70 can be in stable surface contact with the second inclined surface 66f of the second cutout portion 66 without having to process the second cutout portion 66 and the second protrusion portion 70 under strict manufacturing conditions. This reduces the manufacturing cost of the cutting unit 10.

[0064] When the second inclined surface 66f of the second cutout portion 66 of the holder 16 is a convex curved surface and the second abutment surface 70f of the second protrusion portion 70 of the pressing piece 60 is a flat surface, the second abutment surface 70f of the second protrusion portion 70 can be in stable surface contact with the second inclined surface 66f of the second cutout portion 66 without having to process the second cutout portion 66 and the second protrusion portion 70 under strict manufacturing conditions. This allows the manufacturing cost of the cutting unit 10 to be reduced.

[0065] When the second inclined surface 66f of the second cutout portion 66 of the holder 16 and the second abutment surface 70f of the second protrusion 70 of the pressing piece 60 are each flat surfaces, it is necessary to ensure parallelism between the second inclined surface 66f of the second cutout portion 66 and the second abutment surface 70f of the second protrusion 70 in order to bring them into surface contact with each other. Therefore, in the above case, it is necessary to process the second cutout portion 66 and the second protrusion 70 under strict manufacturing conditions.

[0066] <Method of manufacturing machined products> A method for manufacturing a machined product according to an embodiment of the present disclosure will be described with reference to Figures 16 to 18. Figures 16 to 18 are schematic views for explaining a method for manufacturing a machined product according to an embodiment of the present disclosure.

[0067] As shown in the examples of FIGS. 16 to 18 , the method for manufacturing a machined product according to an embodiment of the present disclosure is a method for manufacturing a machined product M, which is a workpiece W that has been machined, and includes a first step, a second step, and a third step. The first step is a step of rotating the workpiece W around its axis S. The second step is a step of bringing the cutting edge 44 of the cutting insert 18 in the cutting unit 10 into contact with the rotating workpiece W to cut the workpiece W. The third step is a step of separating the cutting edge 44 of the cutting insert 18 from the cut workpiece W. Examples of materials for the workpiece W include stainless steel, carbon steel, alloy steel, cast iron, and non-ferrous metals. The specific details of the method for manufacturing a machined product according to the embodiment are as follows.

[0068] First, the cutting unit 10 is attached to the machining head of a lathe, and the workpiece W is attached to the chuck of the lathe. Next, as shown in the example of FIG. 16, the chuck is rotated to rotate the workpiece W around its axis S (first step). Then, as shown in the example of FIG. 17, the cutting unit 10 is brought close to the end face of the workpiece W and moved along the axis S of the workpiece W. This brings the cutting edge 44 of the cutting insert 18 close to the workpiece W, bringing the cutting insert 18 into contact with the rotating workpiece W and cutting the workpiece W (second step), thereby forming a machined surface Wf on the workpiece W.

[0069] 16, the cutting unit 10 is then moved in a direction away from the axis S of the workpiece W, thereby moving the cutting edge 44 of the cutting insert 18 away from the workpiece W (third step). This completes the cutting of the workpiece W, and a machined product M, which is the machined workpiece W, can be produced. Because the cutting unit 10 has excellent cutting ability for the reasons described above, it is possible to produce a machined product M with excellent processing precision.

[0070] To continue cutting, the cutting edge 44 of the cutting insert 18 may be repeatedly brought into contact with different locations on the workpiece W while the workpiece W is being rotated. In the embodiment of the present disclosure, the cutting edge 44 of the cutting insert 18 is brought close to the workpiece W, but since it is only necessary that the cutting edge 44 of the cutting insert 18 and the workpiece W are brought relatively close to each other, the workpiece W may also be brought close to the cutting edge 44 of the cutting insert 18. In this regard, the cutting edge 44 of the cutting insert 18 is moved away from the workpiece W in a similar manner.

[0071] In one embodiment, (1) the cutting unit comprises a holder having a rectangular prism shape extending from the tip to the rear end, and having a tip surface located on the tip side, an upper surface extending from the tip surface toward the rear end, a lower surface located opposite the upper surface, a first side surface located between the upper surface and the lower surface and extending from the tip surface toward the rear end, and a second side surface located opposite the first side surface; a holding block having a cutting blade located at the tip and on the side of the first side surface and a groove for holding the holder; and a clamp member located on the holding block and interposed between one inner surface of the groove and the upper surface, having a pressing portion for pressing the holder toward the other inner surface of the groove, and fixing the holder to the holding block. The upper surface has a first notch having a first inclined surface that moves away from the lower surface as it approaches the rear end, and a second notch located closer to the rear end than the first notch and having a second inclined surface that moves away from the lower surface as it approaches the rear end. The pressing portion has a first protrusion that abuts on the first inclined surface, and a second protrusion that is spaced from the first protrusion and abuts on the second inclined surface.

[0072] (2) In the cutting unit of (1) above, the first cutout portion and the second cutout portion may be open to the first side surface and the second side surface, respectively.

[0073] (3) In the cutting unit of (1) or (2) above, the first side surface may abut against a bottom surface of the groove.

[0074] (4) In the cutting unit according to any one of (1) to (3), the width of the first cutout portion in the longitudinal direction of the holder may be greater on the second side surface side than on the first side surface side.

[0075] (5) In the cutting unit according to any one of (1) to (4), the first cutout may be deeper on the side of the second side surface than on the side of the first side surface.

[0076] (6) In any of the cutting units (1) to (5), the depth of the second notch may be deeper on the side of the second side surface than on the side of the first side surface, and in a cross section perpendicular to the longitudinal direction of the holder, the inclination angle of the first inclined surface relative to an imaginary plane parallel to the lower surface may be greater than the inclination angle of the second inclined surface relative to an imaginary plane parallel to the lower surface.

[0077] (7) In any one of the cutting units (1) to (6) above, the maximum depth of the first cutout portion may be greater than the maximum depth of the second cutout portion.

[0078] (8) In any of the cutting units (1) to (7), the first protrusion may have a first abutment surface that abuts against the first inclined surface, the first inclined surface may be a flat surface, and the first abutment surface may be a convex curved surface.

[0079] (9) In any of the cutting units (1) to (7), the first protrusion may have a first abutment surface that abuts against the first inclined surface, the first inclined surface may be a convex curved surface, and the first abutment surface may be a flat surface.

[0080] (10) In the cutting unit according to any one of (1) to (9), the width of the first notch may be greater than the width of the first protrusion in a cross section along the longitudinal direction of the clamp member.

[0081] (11) A cutting tool includes a holder having a rectangular prism shape extending from a front end to a rear end, the holder having a front end surface located on the front end side, an upper surface extending from the front end surface toward the rear end, a lower surface located opposite the upper surface, a first side surface located between the upper surface and the lower surface and extending from the front end surface toward the rear end, and a second side surface located opposite the first side surface, and a cutting blade located at the front end and on the side of the first side surface. The upper surface has a first inclined surface that moves away from the lower surface as it approaches the rear end, and a first cutout portion that opens to the first side surface and the second side surface, and a second cutout portion that is located closer to the rear end than the first cutout and has a second inclined surface that moves away from the lower surface as it approaches the rear end, and that opens to the first side surface and the second side surface.

[0082] (12) A tool rest capable of mounting the cutting tool of (11) above includes a holding block having a groove for holding a holder of the cutting tool, and a clamp member located on the holding block and having a pressing part interposed between one inner surface of the groove and the upper surface to press the holder toward the other inner surface of the groove, thereby fixing the holder to the holding block. The pressing part has a first protrusion that abuts against the first inclined surface and a second protrusion that is spaced from the first protrusion and abuts against the second inclined surface.

[0083] (13) A method for manufacturing a machined product includes the steps of rotating a workpiece, bringing a cutting blade of a cutting unit described in any one of claims 1 to 10 into contact with the rotating workpiece, and moving the cutting blade of the cutting unit away from the workpiece.

[0084] The invention according to the present disclosure has been described above based on the drawings and embodiments. However, the invention according to the present disclosure is not limited to the above-described embodiments. In other words, the invention according to the present disclosure can be modified in various ways within the scope of the present disclosure, and embodiments obtained by appropriately combining the technical means disclosed in different embodiments are also included in the technical scope of the invention according to the present disclosure. In other words, it should be noted that a person skilled in the art can easily make various modifications or corrections based on the present disclosure. It should also be noted that these modifications or corrections are included in the scope of the present disclosure. [Explanation of symbols]

[0085] 10 Cutting unit 12 Cutting tools 14 Tool rest 16 Holder 16a tip 16b rear end 16m main body 18 Cutting inserts 20 clamp screws 22 Tip surface 24 Rear end surface 26 Top side 28 Bottom side 30 First aspect 32 Second aspect 34 pockets 36 screw holes 38 First insert surface 40 Second insert surface 42 Insert side 44 cutting edge 46 Holding Block 48 Clamping member 50 Fixing bolt 52 Groove 52a bottom 52b One inner surface (first inner surface) 52c The other inner surface (second inner surface) 52g guide surface 52s center line 54 screw holes 56 Mounting piece (mounting part) 58 Through Hole 60 Pressing piece (pressing part) 60f sliding surface 62 Step 64 First notch 64f 1st slope 66 Second notch 66f 2nd slope 68 1st protrusion 68f 1st contact surface 70 Second protrusion 70f 2nd contact surface

Claims

1. It has a rectangular prism shape that extends from the tip to the rear end, a tip surface located on the tip side; an upper surface extending from the tip surface toward the rear end; a lower surface located opposite the upper surface; a first side surface located between the upper surface and the lower surface and extending from the tip surface toward the rear end; a holder having a second side opposite the first side; a cutting edge located at the tip and on the first side surface; a holding block having a groove for holding the holder; a clamp member that is located on the holding block, has a pressing portion that presses the holder toward the other inner surface of the groove while being interposed between one inner surface of the groove and the upper surface, and fixes the holder to the holding block; The upper surface is a first notch having a first inclined surface that moves away from the lower surface toward the rear end; a second notch portion located closer to the rear end than the first notch portion and having a second inclined surface that becomes increasingly separated from the lower surface as it approaches the rear end, The pressing portion is a first protrusion that contacts the first inclined surface; a second protrusion spaced from the first protrusion and abutting the second inclined surface.

2. The cutting unit according to claim 1 , wherein the first cutout portion and the second cutout portion are open to the first side surface and the second side surface, respectively.

3. The cutting unit according to claim 2 , wherein the first side surface abuts against a bottom surface of the groove.

4. The cutting unit according to claim 3 , wherein the width of the first cutout portion in the longitudinal direction of the holder is greater on the second side surface side than on the first side surface side.

5. The cutting unit according to claim 3 , wherein the depth of the first cutout portion is greater on the side of the second side surface than on the side of the first side surface.

6. a depth of the second cutout portion is deeper on the second side surface side than on the first side surface side; 6. The cutting unit according to claim 5, wherein in a cross section perpendicular to the longitudinal direction of the holder, the inclination angle of the first inclined surface with respect to an imaginary plane parallel to the lower surface is larger than the inclination angle of the second inclined surface with respect to an imaginary plane parallel to the lower surface.

7. The cutting unit according to claim 3 , wherein a maximum value of the depth of the first notch is greater than a maximum value of the depth of the second notch.

8. the first protrusion has a first abutment surface that abuts against the first inclined surface, The cutting unit according to claim 1 , wherein the first inclined surface is a flat surface, and the first abutting surface is a convex curved surface.

9. the first protrusion has a first abutment surface that abuts against the first inclined surface, The cutting unit according to claim 1 , wherein the first inclined surface is a convex curved surface, and the first abutting surface is a flat surface.

10. The cutting unit according to claim 1 , wherein a width of the first notch is greater than a width of the first protrusion in a cross section along the longitudinal direction of the clamp member.

11. It has a rectangular prism shape that extends from the tip to the rear end. a tip surface located on the tip side; an upper surface extending from the tip surface toward the rear end; a lower surface located opposite the upper surface; a first side surface located between the upper surface and the lower surface and extending from the tip surface toward the rear end; a holder having a second side opposite the first side; a cutting edge located at the tip and on the first side surface side; The upper surface is a first notch portion having a first inclined surface that moves away from the lower surface toward the rear end and that is open to the first side surface and the second side surface; a second notch portion that is located closer to the rear end than the first notch portion, has a second inclined surface that moves away from the lower surface as it approaches the rear end, and is open to the first side surface and the second side surface.

12. A tool rest to which the cutting tool according to claim 11 can be attached, a holding block having a groove for holding a holder of a cutting tool; a clamp member that is located on the holding block, has a pressing portion that presses the holder toward the other inner surface of the groove while being interposed between one inner surface of the groove and the upper surface, and fixes the holder to the holding block; The pressing portion is a first protrusion that contacts the first inclined surface; a second protrusion spaced from the first protrusion and abutting the second inclined surface.

13. rotating the workpiece; a step of bringing a cutting blade of the cutting unit according to any one of claims 1 to 10 into contact with the rotating workpiece; and moving the cutting blade of the cutting unit away from the workpiece.

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