Holder, cutting tool, and method for manufacturing machined product

Abstract

A holder based on an aspect of the present disclosure extends from a first end to a second end along a central axis, and includes a first member, a second member, and a fixture. The first member includes a first end surface, a first outer peripheral surface, a protrusion portion including a first surface facing toward the second end, and a first hole extending from the first surface. The second member includes a second end surface opposite to the first end surface, a second outer peripheral surface extending from the second end surface, and a second hole extending from the second outer peripheral surface toward the first hole. The fixture is inserted into the first hole through the second hole, and the protrusion portion is located on the central axis.

Description

Holder, cutting tool, and method for manufacturing machined product CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims priority to Japanese Patent Application No. 2023-029999, filed on February 28, 2023, the entire disclosure of which is incorporated herein by reference.

[0002] The present disclosure relates to a holder, a cutting tool, and a method for manufacturing a machined product, and more particularly to a holder having two members, a cutting tool, and a method for manufacturing a machined product.

[0003] Known examples of holders for cutting tools used in cutting workpieces include holders described in Japanese Patent Publication No. 2001-502252 (Patent Document 1) and Japanese Patent Publication No. 2016-516600 (Patent Document 2). The holders for the cutting tools described in these patent documents are made up of two members: a first component and a second component.

[0004] When a holder is made up of a plurality of members, there is a demand for further improvement in the stability of the connections between these members.

[0005] A holder according to one aspect of the present disclosure has a rod shape extending from a first end to a second end along a central axis, and includes a first member located near the first end, a second member located near the second end relative to the first member, and a fastener for fastening the first member to the second member. The first member has a first end face located near the second end, a first outer peripheral surface extending from the first end face toward the first end, a protrusion extending from the first end face toward the second end and having a first surface facing the second end, and a first hole extending from the first surface toward the first end. The second member has a second end face located near the first end and facing the first end face, a second outer peripheral surface extending from the second end face toward the second end, and a second hole extending from the second outer peripheral surface toward the first hole. The fastener is inserted into the first hole through the second hole, and the protrusion is positioned on the central axis.

[0006] 5 is a top view showing a holder according to one embodiment; FIG. 1 is a perspective view of the holder shown in FIG. 1 as seen from direction A1; FIG. 2 is a perspective view of a state in which the first member and the second member shown in FIG. 2 are disassembled; FIG. 3 is a perspective view of the first member, the second member, etc. shown in FIG. 3 as seen from direction A2; FIG. 1 is a plan view of the holder shown in FIG. 1 as seen from above; FIG. 5 is an enlarged view of region B1 shown in FIG. 5; FIG. 6 is a plan view of the first member shown in FIG. 5; FIG. 7 is a plan view of the first member as seen from the second end side; FIG. 8 is a plan view of the second member as seen from the first end side; FIG. 1 is a plan view of the holder shown in FIG. 1 as seen from direction A3; FIG. 3 is a plan view of the first member shown in FIG. 3 as seen from direction A4; FIG. 5 is a schematic explanatory view showing one step of a method for manufacturing a machined product according to one embodiment; FIG. 6 is a schematic explanatory view showing one step of a method for manufacturing a machined product according to one embodiment;

[0007] <Holder> Hereinafter, a holder 1 according to a non-limiting 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 main components necessary for explaining each embodiment in a simplified form. Therefore, the holder 1 according to the present disclosure may include any component not shown in the drawings. Furthermore, the dimensions of the components in the drawings do not faithfully represent the actual dimensions of the component components, the dimensional ratios of the components, etc.

[0008] 1 to 4, the holder 1 of the present disclosure has a rod shape extending from a first end 1a to a second end 1b along a central axis O1. The central axis O1 is an axis passing through the center of the holder 1. Hereinafter, for convenience of explanation, the first end 1a will be referred to as the front end 1a, and the second end 1b will be referred to as the rear end 1b.

[0009] The holder 1 has a first member 3 located on the side of the front end 1a, a second member 5 located on the side of the rear end 1b of the first member 3, and a fixture 7 that fixes the first member 3 to the second member 5. In the holder 1 shown in this embodiment, the first member 3 is called a head or the like and is a portion to which a cutting insert is attached. The second member 5 is called a shank or the like and is a portion that is gripped by a machine tool. In a non-limiting example shown in Figures 1 to 4, the first member 3 includes the front end 1a, and the second member 5 includes the rear end 1b.

[0010] Fig. 1 is a plan view of the holder 1 as viewed from above, Fig. 2 is a perspective view of the holder 1 as viewed from the A1 direction shown in Fig. 1, Fig. 3 is a perspective view showing the first member 3 shown in Fig. 2 separated from the second member 5, and showing the first member 3, the second member 5, and the fixing device 7 disassembled. Fig. 4 is a perspective view of the holder 1 shown in Fig. 3 as viewed from the A2 direction.

[0011] As a non-limiting example shown in FIGS. 3 and 4 , the first member 3 has a first tip surface 9 located on the tip end 1 a side, a first rear end surface 11 (first end surface) located on the rear end 1 b side, and a first outer circumferential surface 13 located between the first tip surface 9 and the first rear end surface 11.

[0012] The first outer peripheral surface 13 extends from the first rear end surface 11 toward the front end 1a. The first outer peripheral surface 13 has a first upper surface 15 (upper surface), a first lower surface 17 (lower surface) located opposite the first upper surface 15, a first front surface 19 located between the first upper surface 15 and the first lower surface 17, and a first back surface 21 located opposite the first front surface 19. The first front end surface 9, the first rear end surface 11, the first upper surface 15, the first lower surface 17, the first front surface 19, and the first back surface 21 may each have a flat shape.

[0013] Furthermore, the first member 3 has a pocket 23 located on the side of the front end 1a and opening in the first front end surface 9, the first upper surface 15, and the first front surface 19, and a protrusion 25 extending from the first rear end surface 11 toward the rear end 1b. The protrusion 25 may have a cylindrical or conical shape extending along the central axis O1. Here, the cylindrical shape (conical shape) does not necessarily have to be a cylinder (cone) in the strict sense, and may have a hole, as shown in a non-limiting example in FIG. 4 .

[0014] The pocket 23 is a portion where a cutting insert is attached. The cutting insert may be fixed to the pocket 23 by a fixing member such as a fixing screw or a clamp. Note that, for the purpose of specifying the position of the pocket 23 in the first member 3, the first front surface 19 may be conveniently replaced with a lateral surface.

[0015] The protrusion 25 has a first surface 27 facing the rear end 1b. Facing the rear end 1b does not mean that the first surface 27 is necessarily perpendicular to the central axis O1, but if the first surface 27 is substantially perpendicular to the central axis O1, the holder 1 will have high holding stability. "Substantially perpendicular" means that the angle between the first surface 27 and the central axis O1 is within a range of ±5°.

[0016] Furthermore, the protrusion 25 has a first opening 29 located in the first surface 27. The first member 3 may have a first hole 31 extending from the first opening 29 toward the tip 1 a. In other words, the first member 3 may have the first hole 31 extending from the first surface 27 toward the tip 1 a, and the first hole 31 may have the first opening 29 located in the first surface 27. In the holder 1 shown in this embodiment, the first member 3 has the entire first hole 31.

[0017] The first holes 31 may approach either surface of the first outer peripheral surface 13 as they move toward the tip 1a. In a non-limiting example shown in Figures 5 to 7, the first holes 31 approach the first front surface 19 as they move toward the tip 1a. Here, Figure 5 is a plan view seen through from above of the holder 1 shown in Figure 1, Figure 6 is an enlarged view corresponding to region B1 shown in Figure 5, and Figure 7 is a plan view of the first member 3 shown in Figure 5.

[0018] The second member 5 has a second tip surface 33 (second end surface) located on the side of the tip 1a and facing the first rear end surface 11, a second rear end surface 35 located on the opposite side from the second tip surface 33, and a second outer peripheral surface 37 located between the second tip surface 33 and the second rear end surface 35.

[0019] The second outer peripheral surface 37 extends from the second front end surface 33 toward the rear end 1b. The second outer peripheral surface 37 has a second upper surface 39, a second lower surface 41 located opposite the second upper surface 39, a second front surface 43 located between the second upper surface 39 and the second lower surface 41, and a second rear surface 45 (rear surface) located opposite the second front surface 43. The second front end surface 33, the second rear end surface 35, the second upper surface 39, the second lower surface 41, the second front surface 43, and the second rear surface 45 may each be flat. The second front surface 43 may face the same side as the first front surface 19. The second rear surface 45 may face the opposite side to the second front surface 43.

[0020] 1 to 4, the directions in which the first upper surface 15, the first lower surface 17, the first front surface 19, and the first rear surface 21 face are the same as the directions in which the second upper surface 39, the second lower surface 41, the second front surface 43, and the second rear surface 45 face, respectively. In the non-limiting example shown in Figures 1 to 4, the first upper surface 15 is continuous with the second upper surface 39, the first lower surface 17 is continuous with the second lower surface 41, the first front surface 19 is continuous with the second front surface 43, and the first rear surface 21 is continuous with the second rear surface 45.

[0021] For ease of explanation, the direction in which the second upper surface 39 faces will be referred to as the upper side, the direction in which the second lower surface 41 faces will be referred to as the lower side, the direction in which the second front surface 43 faces will be referred to as the foreside, and the direction in which the second back surface 45 faces will be referred to as the backside.

[0022] The second outer peripheral surface 37 has a second opening 47 (opening). In a non-limiting example shown in FIG. 4 , the second opening 47 is located on the second back surface 45. The second member 5 also has a second hole 49 extending from the second opening 47 toward the tip 1 a. In other words, the second member 5 may have the second hole 49 extending from the second outer peripheral surface 37 toward the tip 1 a, and the second hole 49 may have the second opening 47 located on the second outer peripheral surface 37. The second hole 49 may extend from the second outer peripheral surface 37 toward the first hole 31. The second opening 47 may allow the fastener 7 to be inserted therein.

[0023] In the holder 1 shown in this embodiment, the second member 5 has the entire second hole 49. The second hole 49 may approach either surface of the second outer peripheral surface 37 as it moves toward the tip 1 a. In a non-limiting example shown in Figures 5 and 6, the second hole 49 approaches the second front surface 43 as it moves toward the tip 1 a.

[0024] Examples of the portion into which the fastener 7 is inserted include the first hole 31 and the second hole 49, but the portion into which the fastener 7 is inserted is not limited to these. In addition to the first hole 31 and the second hole 49, the portion into which the fastener 7 is inserted may also have a portion that connects these holes.

[0025] The second member 5 has a recess 50 located closer to the front end 1 a than the second hole 49. In the holder 1 shown in this embodiment, the protrusion 25 is inserted into the recess 50. The inner diameter of the recess 50 may be larger than the inner diameter of the second hole 49. The recess 50 may be connected to the second hole 49 on the rear end 1 b side.

[0026] In the holder 1 shown in this embodiment, the end of the second hole 49 on the side of the tip 1 a is located at the end of the recess 50 on the side of the rear end 1 b. More specifically, the recess 50 has a second surface 51 located on the side of the rear end 1 b, and the second hole 49 has a third opening 53 located at the end on the side of the tip 1 a. The third opening 53 is located on the second surface 51 of the recess 50.

[0027] Furthermore, the second surface 51 may face the first surface 27. In order to make it easier for the protrusion 25 to be inserted into the recess 50, the inner diameter of the recess 50 may be slightly larger than the outer diameter of the protrusion 25, i.e., a slight "play" may be provided between the recess 50 and the protrusion 25.

[0028] The fastener 7 is inserted into the first hole 31 through the second hole 49. The type of fastener 7 is not particularly limited, and may be a screw and / or a clamp, etc. The method of fastening using the fastener 7 is not particularly limited, but in the holder 1 shown in this embodiment, the fastener 7 and the first hole 31 are provided with threads, and by tightening the fastener 7 inserted into the first hole 31, the second member 5 moves relatively closer to the first member 3, and the first member 3 is fixed to the second member 5.

[0029] In the first hole 31, the portion where the threads are provided may be located closer to the tip 1 a than the portion where the threads are not provided. In such a case, the inner diameter of the portion where the threads are provided may be smaller than the inner diameter of the portion where the threads are not provided.

[0030] Here, second hole 49 does not have to be provided with a thread. Also, the inner diameter of second hole 49 may be slightly larger than the outer diameter of fastener 7, i.e., a slight amount of "play" may be provided between second hole 49 and fastener 7. In such a case, second hole 49 is less likely to be an obstacle when fastener 7 is inserted into first hole 31, making it easier for fastener 7 to be inserted into first hole 31.

[0031] The protrusion 25 is located on the central axis O1. In other words, the central axis O1 passes through the protrusion 25. In a non-limiting example shown in Fig. 8, the central axis O1 passes through the center P1 of the first rear end face 11, and the center P1 of the first rear end face 11 is located on the protrusion 25. Specifically, the center P1 of the first rear end face 11 is located on the first surface 27. Here, Fig. 8 is a plan view of the first member 3 as seen from the rear end 1b side, and Fig. 9 is a plan view of the second member 5 as seen from the front end 1a side.

[0032] 1 and the like has a rectangular prism shape. In such a case, the central axis of the second member 5 may be regarded as the central axis O1 of the holder 1. In the above case, the central axis of the second member 5, which passes through the center P2 of the second rear end surface 35 and extends in a direction parallel to the second outer peripheral surface 37, may be regarded as the central axis O1 of the holder 1.

[0033] When the head is fixed by inserting the fastener 7 from the shank, an opening for inserting the fastener 7 may be provided on the side of the shank from the viewpoint of ease of insertion of the fastener 7. However, in such a case, if the protrusion 25 is provided only on the top surface of the head, as shown in Patent Document 1, the hole in the center of the head is located closer to the tip 1a, which tends to reduce the rigidity of the head.

[0034] On the other hand, in the holder 1 shown in this embodiment, the central axis O1 passes through the protrusion 25, i.e., the protrusion 25 is located at the center P1 of the first rear end face 11, so the rigidity of the first member 3 is increased, and in addition, the cutting load applied to the first member 3 can be stably received by the second member 5. Therefore, the holder 1 has high holding stability and high coupling stability. Furthermore, when the first surface 27 is located on the central axis O1, in other words, when the central axis O1 passes through the first surface 27, the rigidity of the first member 3 is likely to be higher.

[0035] The end of the first member 3 on the side of the rear end 1b may be located on the protrusion 25. More specifically, the end of the first member 3 on the side of the rear end 1b may be located on the first surface 27. In such a case, the first member 3 can be easily inserted into the second member 5. In addition, the rigidity of the portion of the second member 5 that is joined to the first member 3 and that is located on the side of the front end 1a is increased.

[0036] The end of the second member 5 on the side of the tip 1 a may be located on the second tip surface 33. In this case, it becomes easier to insert the first member 3 into the second member 5. In addition, the rigidity of the portion of the first member 3 that is joined to the second member 5 and is located on the side of the tip 1 a becomes higher.

[0037] 4 , the fixture 7 may have a shaft portion 54 extending along the axis of the fixture 7. The shaft portion 54 may have a thread groove on the side of the tip 1a. In the holder 1 shown in this embodiment, the first hole 31 is provided with a thread groove, while the second hole 49 is not provided with a thread groove. Therefore, it is sufficient that the portion of the shaft portion 54 that is inserted into the first hole 31 is provided with a thread groove. In such a case, the outer diameter of the portion of the shaft portion 54 that has the thread groove may be smaller than the outer diameter of the portion of the shaft portion 54 that does not have the thread groove.

[0038] 4 , the fastener 7 may have a head 55 located closer to the rear end 1 b than the shank 54. The head 55 may have an outer diameter larger than that of the shank 54. In such a case, when fastening the first member 3 to the second member 5, the fastener 7 can be tightened to apply a force from the head 55 to the second member 5 in the direction of the tip 1 a, thereby more efficiently bringing the second member 5 closer to the first member 3.

[0039] 6 , in a non-limiting example, when the second hole 49 has a small diameter portion 49a located on the side of the tip 1a and a large diameter portion 49b having an inner diameter larger than that of the small diameter portion 49a and located on the side of the rear end 1b of the small diameter portion 49a, the head portion 55 may be configured to abut against a third surface 56 located between the small diameter portion 49a and the large diameter portion 49b, thereby applying a force from the head portion 55 to the second member 5 in the direction of the tip 1a. In this case, the small diameter portion 49a may be connected to the large diameter portion 49b, and the large diameter portion 49b may have the third surface 56.

[0040] In addition, the head portion 55 may be spaced apart from the first member 3. In such a case, the head portion 55 can apply force to the second member 5 in the direction of the tip 1a more efficiently.

[0041] The second opening 47 may be located on the back surface. In the holder 1 shown in this embodiment, the second opening 47 is located on the second back surface 45. When the second member 5 is attached to a machine tool, the second back surface 45 generally faces the operator. Therefore, when the holder 1 has the above configuration, it is easy to insert the fixing device 7 into the second member 5.

[0042] The protrusion 25 may be spaced apart from the side surface. In the holder 1 shown in this embodiment, the protrusion 25 is spaced apart from the first outer peripheral surface 13. In this case, it becomes easier to insert the first member 3 into the second member 5 from the tip 1 a side.

[0043] 7 , at least a portion of the first hole 31 may be located closer to the front end 1 a than the protrusion 25. In such a case, the protrusion 25 is not longer than necessary, making it easier to insert the first member 3 into the second member 5. The fastener 7 may also be located closer to the rear end 1 b than the first rear end surface 11. In the holder 1 shown in this embodiment, the entire fastener 7 is located closer to the rear end 1 b than the first rear end surface 11.

[0044] The first opening 29 may be located closer to the rear surface than the central axis O1. In such a case, the first hole 31 is likely to be located closer to the rear surface, and the first hole 31 is likely to be located away from the pocket 23. As a result, the rigidity of the first member 3 is likely to be high. In a non-limiting example shown in FIG. 8 , the entire first opening 29 is located closer to the rear surface than the central axis O1, i.e., on the side of the first rear surface 21.

[0045] The center of the second opening 47 may be located on the lower side. In the holder 1 shown in this embodiment, the center of the second opening 47 is located on the side of the second lower surface 41. In such a case, the first hole 31 communicating with the second hole 49 is also located on the lower side, and therefore the first hole 31 is likely to be located away from the pocket 23. As a result, the rigidity of the first member 3 is likely to be high. In a non-limiting example shown in Figure 10, at least a portion of the second opening 47 is located below the central axis O1. Here, Figure 10 is a plan view of the holder 1 shown in Figure 1 as viewed from the A3 direction.

[0046] When the first member 3 is viewed from the rear end 1b side, the protrusion 25 may be asymmetric with respect to the central axis O1. In other words, the protrusion 25 does not have to have n-fold symmetry (n is an integer greater than or equal to 2) around the central axis O1. For example, when the first member 3 is viewed from the rear end 1b side, the center of the protrusion 25 may be spaced apart from the central axis O1. In addition, being asymmetric means, for example, that the first surface 27 is elliptical or polygonal with rounded vertices. In such a case, mistakes such as installing the first member 3 upside down are less likely to occur when installing the first member 3.

[0047] The fastener 7 may have a bottom portion 57 located on the side of the distal end 1a. The fastener 7 may also have a head end portion 58 located on the side of the proximal end 1b. The bottom portion 57 and the head end portion 58 may be end portions in a direction along the central axis O2 of the fastener 7. In a non-limiting example shown in FIG. 6 , a center P3 of the bottom portion 57 and a center P4 of the head end portion 58 may pass through the central axis O2 of the fastener 7.

[0048] Here, the imaginary line segment connecting the center P3 of the bottom portion 57 and the center P4 of the head end portion 58 is defined as the axis S of the fixture 7. When the axis S is viewed from a direction perpendicular to both the axis S and the central axis O1, in other words, when viewed from a direction perpendicular to the axis S and the central axis O1, the length L1 of the axis S in the direction along the central axis O1 may be longer than the length L2 of the axis S in the direction perpendicular to the central axis O1. In such a case, the first member 3 is more easily moved toward the rear end 1b, or the second member 5 is more easily moved toward the front end 1a. Here, the case where the axis S is viewed from a direction perpendicular to both the axis S and the central axis O1 may also be the case where the axis S is viewed from a direction perpendicular to the second top surface 39.

[0049] Furthermore, the axis S may be located closer to the lower surface (first lower surface 17) than the central axis O1. In such a case, the first hole 31 communicating with the second hole 49 is also located on the lower side, and therefore the first hole 31 is likely to be located away from the pocket 23. As a result, the rigidity of the first member 3 is likely to be high.

[0050] The protrusion 25 may further have a peripheral wall portion 59 connected to the first surface 27 and the first rear end surface 11. Furthermore, the outer diameter of the protrusion 25 may decrease from the front end 1a toward the rear end 1b. In such a case, the holding stability between the first member 3 and the second member 5 is likely to be improved. As a non-limiting example shown in FIGS. 7 and 11, the peripheral wall portion 59 may have a tapered shape in which the outer diameter decreases from the front end 1a toward the rear end 1b. Here, FIG. 11 is a plan view of the first member 3 shown in FIG. 3 as viewed from the A4 direction.

[0051] Furthermore, the inclination θ1 of the peripheral wall portion 59 with respect to the central axis O1 may be smaller than the inclination θ2 of the axis S with respect to the central axis O1. In such a case, the inclination of the fastener 7 with respect to the central axis O1 becomes relatively small, making it easier to retract the first member 3 and / or the second member 5 in the direction along the central axis O1. In a non-limiting example shown in FIGS. 5 and 6 , the inclination θ1 of the peripheral wall portion 59 with respect to the central axis O1 is smaller than the inclination θ2 of the axis S with respect to the central axis O1. The magnitude relationship of the above inclinations may be evaluated when viewed from the top surface (first top surface 15).

[0052] The sizes of the first member 3 and the second member 5 are not particularly limited. For example, the length from the front end 1a to the first rear end surface 11 may be 10 to 100 mm. The length from the first upper surface 15 to the first lower surface 17 may be 5 to 50 mm. The length from the second front end surface 33 to the rear end 1b may be 50 to 200 mm. The length from the second upper surface 39 to the second lower surface 41 may be 5 to 50 mm.

[0053] The holder 1 may be made of a material such as steel, cast iron, or cemented carbide.

[0054] <Cutting Tool> Next, a cutting tool according to an embodiment of the present disclosure will be described with reference to the drawings.

[0055] 12 to 14, a cutting tool 101 according to the present disclosure has a rod shape extending from a leading end 1a to a trailing end 1b. The cutting tool 101 includes a holder 1 and a cutting insert 103 fixed to the holder 1. The cutting insert 103 may be positioned in a pocket 23 in the holder 1. The cutting insert 103 has a through hole 105.

[0056] 12 to 14 includes an insert screw 109 that can be used to fix the cutting insert 103 in the pocket 23. In the non-limiting example shown in FIG. 1 , the pocket 23 may have a pocket hole 111 that extends from the first upper surface 11 side toward the first lower surface 13 side. By inserting the insert screw 109 into the through hole 105 in the cutting insert 103 and the pocket hole 111 in the pocket 23, the cutting insert 103 can be fixed in the pocket 23.

[0057] Examples of materials for the cutting insert 103 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.

[0058] Cermets are sintered composite materials in which a ceramic component is combined with a metal, and specifically, cermets include materials containing titanium compounds such as titanium carbide (TiC) and titanium nitride (TiN) as their main components.

[0059] The surface of the cutting insert 103 may be coated with a film by chemical vapor deposition (CVD) or physical vapor deposition (PVD). The composition of the film may be titanium carbide (TiC), titanium nitride (TiN), titanium carbonitride (TiCN), and alumina (Al ２ O ３ ) etc.

[0060] <Method for Manufacturing Machined Product> Next, a method for manufacturing a machined product according to an embodiment of the present disclosure will be described with reference to the drawings.

[0061] The machined product is produced by cutting a workpiece 201. The manufacturing method of the machined product in the present disclosure includes the following steps: (C1) a step of rotating the workpiece 201; (C2) a step of bringing the cutting tool 101 into contact with the rotating workpiece 201; and (C3) a step of separating the cutting tool 101 from the workpiece 201.

[0062] More specifically, first, as shown in a non-limiting example in Fig. 12, the workpiece 201 is rotated around the rotation axis O3, and the cutting tool 101 is brought relatively close to the workpiece 201. Next, as shown in a non-limiting example in Fig. 13, the cutting edge 107 of the cutting tool 101 is brought into contact with the rotating workpiece 201 to cut the workpiece 201. Then, as shown in a non-limiting example in Fig. 14, the cutting tool 101 is moved relatively away from the workpiece 201.

[0063] In the embodiment, the cutting tool 101 is moved in the Y1 direction while the rotation axis O3 is fixed and the workpiece 201 is rotated, thereby bringing the cutting tool 101 closer to the workpiece 201. In a non-limiting example shown in Fig. 13, the cutting edge 107 of the insert is brought into contact with the rotating workpiece 201 to cut the workpiece 201. In a non-limiting example shown in Fig. 14, the cutting tool 101 is moved in the Y2 direction while the workpiece 201 is rotated, thereby moving the cutting tool 101 away from the workpiece 201.

[0064] In the cutting process in the manufacturing method of the embodiment, the cutting tool 101 is moved in each step to bring the cutting tool 101 into contact with the workpiece 201 or to move the cutting tool 101 away from the workpiece 201, but of course, this is not limited to this form.

[0065] For example, in step (C1), the workpiece 201 may be brought closer to the cutting tool 101. Similarly, in step (C3), the workpiece 201 may be moved away from the cutting tool 101. To continue the cutting process, the workpiece 201 may be kept rotating, and the step of bringing the cutting edge 107 of the insert into contact with different locations on the workpiece 201 may be repeated.

[0066] The material of the workpiece 201 may be, for example, carbon steel, alloy steel, stainless steel, cast iron, or non-ferrous metal.

[0067] In one embodiment, (1) a rod-shaped holder extending from a first end to a second end along a central axis includes a first member located on the first end side, a second member located closer to the second end than the first member, and a fixture that fixes the first member to the second member, and the first member has a first end face located on the second end side, a first outer circumferential surface extending from the first end face toward the first end, and a second outer circumferential surface extending from the first end face toward the second end, and The second member may have a protrusion having a first surface facing the second end and a first hole extending from the first surface toward the first end, and the second member may have a second end surface located on the first end side and facing the first end surface, a second outer peripheral surface extending from the second end surface toward the second end, and a second hole extending from the second outer peripheral surface toward the first hole, and the fastener may be inserted into the first hole through the second hole, and the protrusion may be located on the central axis.

[0068] (2) In the holder of (1) above, the first surface may be located on the central axis.

[0069] (3) In the holder of (1) or (2) above, an end of the first member on the side of the second end may be located on the protrusion.

[0070] (4) In the holder of (3) above, an end of the first member on the side of the second end may be located on the first surface.

[0071] (5) In the holder according to any one of (1) to (4) above, an end of the second member on the side of the first end may be located on the second end surface.

[0072] (6) In any of the holders (1) to (5) above, the fixing device has a shaft portion extending along the axis of the fixing device, and a head portion located closer to the second end than the shaft portion and having a larger outer diameter than the shaft portion, and the head portion may be spaced apart from the first member.

[0073] (7) In the holder according to any one of (1) to (6) above, the protrusion may be spaced apart from the first outer circumferential surface.

[0074] (8) In the holder according to any one of (1) to (7) above, when the first member is viewed from the second end side, the protrusion may be asymmetric with respect to the central axis.

[0075] (9) In any of the holders (1) to (8) above, when the first end surface is a first rear end surface, the first member may further have a first tip surface located on the first end side, the first outer peripheral surface may have an upper surface, a lower surface located opposite the upper surface, a first front surface located between the upper surface and the lower surface, and a pocket located on the first end side and opening in the first tip surface, the upper surface, and the first front surface, the second outer peripheral surface may have a second front surface facing the same side as the first front surface and a back surface facing the opposite side to the second front surface, and the second opening may be located on the back surface.

[0076] (10) In the holder of (9) above, the axis of the fixing device may be located closer to the lower surface than the central axis.

[0077] (11) In any of the holders (1) to (10) above, the fixture has a bottom located on the side of the first end and a head end located on the side of the second end, and an imaginary line segment connecting the center of the bottom and the center of the head end is the axis of the fixture, and when viewed from a direction perpendicular to the axis and central axis of the fixture, the length of the axis of the fixture in a direction along the central axis may be longer than the length of the axis of the fixture in a direction perpendicular to the central axis.

[0078] (12) In the holder of (11) above, the protrusion further has a peripheral wall portion connected to the first surface and the first end surface, the outer diameter of the protrusion becomes smaller as it moves from the first end side toward the second end side, the first outer surface has an upper surface, and when viewed from the upper surface side, the inclination of the peripheral wall portion relative to the central axis may be smaller than the inclination of the axis of the fixing device relative to the central axis.

[0079] (13) A cutting tool may have the holder of any one of (1) to (12) above and a cutting insert fixed to the holder.

[0080] (14) A method for manufacturing a machined product may include the steps of rotating a workpiece, bringing the cutting tool described above in (13) into contact with the rotating workpiece, and removing the cutting tool from the workpiece.

[0081] 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.

[0082] DESCRIPTION OF SYMBOLS 1 Holder 1a First end (front end) 1b Second end (rear end) 3 First member 5 Second member 7 Fixing device 9 First front end surface 11 First rear end surface 13 First outer peripheral surface 15 First upper surface 17 First lower surface 19 First front surface (side surface) 21 First rear surface 23 Pocket 25 Projection 27 First surface 29 First opening 31 First hole 33 Second front end surface 35 Second rear end surface 37 Second outer peripheral surface 39 Second upper surface 41 Second lower surface 43 Second front surface 45 Second rear surface 47 Second opening 49 Second hole 49a Small diameter portion 49b Large diameter portion 50 Recess 51 Second surface 53 Third opening 54: Shank 55: Head 56: Third surface 57: Bottom 58: Head end 59: Peripheral wall 101: Cutting tool 103: Cutting insert 105: Through hole 107: Cutting edge 109: Insert screw 111: Pocket hole 201: Workpiece O1, O2: Central axis O3: Rotation axis P1 to P4: Center S: Axis of fixture L1, L2: Length θ1, θ2: Inclination Y1, Y2: Direction of movement

Claims

1. A rod shape extending from a first end to a second end along a central axis, a first member located on the side of the first end; a second member located closer to the second end than the first member; a fastener that fastens the first member to the second member, The first member is a first end surface located on the second end side; a first outer circumferential surface extending from the first end surface toward the first end; a protrusion extending from the first end surface toward the second end and having a first surface facing the second end; a first hole extending from the first surface toward the first end, The second member is a second end surface located on the first end side and facing the first end surface; a second outer circumferential surface extending from the second end surface toward the second end; a second hole extending from the second outer circumferential surface toward the first hole, The fastener is inserted into the first hole through the second hole; The protrusion is located on the central axis of the holder.

2. The holder according to claim 1 , wherein the first surface is located on the central axis.

3. The holder according to claim 1 , wherein an end of the first member on the side of the second end is located at the protrusion.

4. The holder according to claim 3 , wherein an end of the first member on the side of the second end is located on the first surface.

5. The holder according to claim 1 , wherein an end of the second member on the side of the first end is located on the second end surface.

6. The fixture is a shaft portion extending along the axis of the fastener; a head portion located closer to the second end than the shaft portion and having an outer diameter larger than that of the shaft portion; The holder of claim 1 , wherein the head is spaced from the first member.

7. The holder according to claim 1 , wherein the protrusion is spaced from the first outer circumferential surface.

8. When the first member is viewed from the second end side, The holder of claim 1 , wherein the protrusion is asymmetric with respect to the central axis.

9. When the first end surface is defined as a first rear end surface, the first member further has a first front end surface located on the first end side, The first outer peripheral surface is The top surface and a lower surface located opposite the upper surface; and a first front surface located between the upper surface and the lower surface; a pocket located on the first end side and opening to the first tip surface, the top surface, and the first front surface; The second outer circumferential surface is a second front surface facing the same side as the first front surface; a back surface facing opposite the second front surface; an opening into which the fastener is inserted; The holder of claim 1 , wherein the opening is located on the rear surface.

10. The holder according to claim 9 , wherein an axis of the fixture is located closer to the lower surface than the central axis.

11. The fixture is a bottom portion located on the side of the first end; a head end located on the second end side, An imaginary line segment connecting the center of the bottom portion and the center of the head end portion is the axis of the fixture, When viewed from a direction perpendicular to the axis and the central axis of the fixing device, The holder of claim 9 , wherein the axial length of the fixture in a direction along the central axis is longer than the axial length of the fixture in a direction perpendicular to the central axis.

12. the protrusion further includes a peripheral wall portion connected to the first surface and the first end surface, an outer diameter of the protrusion decreases from the first end toward the second end, The first outer peripheral surface has an upper surface, When viewed from the top surface side, The holder according to claim 11 , wherein an inclination of the peripheral wall portion relative to the central axis is smaller than an inclination of the axis of the fixture relative to the central axis.

13. A holder according to any one of claims 1 to 12; a cutting insert fixed to the holder.

14. rotating the workpiece; bringing the cutting tool according to claim 13 into contact with the rotating workpiece; and removing the cutting tool from the workpiece.