Holder, cutting tool, and method for manufacturing a machined workpiece

Abstract

The holder is in the shape of a quadrangular prism extending from a first end to a second end. The holder includes a pocket located on the first end side, and a first side surface and a second side surface that extend from the first end to the second end. The second side surface includes a first region that is flat and located on the first end side, a second region that is flat and located closer to the second end and the first side surface than the first region is, and a step portion connecting the first region and the second region. The step portion has a curved shape protruding toward the second end in a cross section parallel to the first region.

Description

Technical Field

[0001] The present disclosure relates to a holder, a cutting tool, and a method for manufacturing a machined product, which are used when machining a workpiece such as metal.

Background Art

[0002] As a cutting tool used when machining a workpiece such as metal, for example, the cutting tools described in Patent Documents 1 and 2 are known. The cutting tools described in Patent Documents 1 and 2 are used in a state of being attached to a tool holder. In order to improve the attachment accuracy to the tool holder, in the cutting tool described in Patent Document 1, a plate-shaped positioning member is attached to the tool body, and the rear end portion of the positioning member is brought into contact with the tool holder. In the cutting tool described in Patent Document 2, a positioning pin is attached to the main body portion, and the positioning pin is abutted against the abutting surface of the tool holder.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Patent Document 2

Summary of the Invention

[0004] A non-limiting example of a holder in the present disclosure has a quadrangular prism shape extending from a first end to a second end. The holder has a pocket located on the side of the first end and capable of attaching a cutting insert, a first side surface extending from the first end to the second end, and a second side surface located opposite to the first side surface. The second side surface has a flat first region located on the side of the first end, a flat second region located closer to the second end than the first region and closer to the first side surface than the first region, and a stepped portion connecting the first region and the second region. And the stepped portion forms a convex curved shape toward the second end in a cross section parallel to the first region.

Brief Description of the Drawings

[0005]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Figure 10

Figure 11

Figure 12

Figure 13

Figure 14

Embodiments for Carrying Out the Invention

[0006] A method for manufacturing a holder, a cutting tool, and a cutting compound, which is an example not limited in the present disclosure, will be described in detail with reference to the drawings. Examples of the cutting tool include, for example, a turning tool. Examples of the turning tool include, for example, a grooving tool and a parting tool. The grooving tool can be used, for example, for grooving. In an example not limited shown in FIG. 1, the cutting tool 100 is a turning tool, and more specifically, a tool for making a groove or a step. In each of the drawings referred to below, for convenience of explanation, only the main members of the members constituting the embodiment not limited are shown in a simplified manner. Therefore, the cutting tool 100 may include any constituent members not shown in each of the drawings referred to. Also, the dimensions of the members in each drawing do not necessarily faithfully represent the dimensions of the actual constituent members and the dimensional ratios of the respective members.

[0007] In each figure, the X-axis direction is the left-right direction, the Z-axis direction is the up-down direction, and the Y-axis direction is the front-back direction. In FIG. 1, the side where the cutting insert 2 is located is the right side in the X-axis direction, the front side in the Y-axis direction, and the upper side in the Z-axis direction. Hereinafter, the cutting insert 2 will be simply referred to as "insert 2".

[0008] An example of the cutting tool 100 shown in FIGS. 1 to 6, which is not limited, has a holder 1, an insert 2, and a screw 3.

[0009] <Holder> The holder 1 may have a quadrangular prism shape extending from the first end 1a, which is the tip, toward the second end 1b, which is the rear end, along the first central axis L1. In FIG. 1, the front side of the holder 1 in the Y-axis direction is the first end 1a, and the rear side is the second end 1b.

[0010] The size of the holder 1 is not particularly limited. For example, the length in the direction along the first central axis L1 can be set to about 10 mm to 250 mm. Also, the height from the upper end to the lower end, in other words, the width in the up-down direction of the Z-axis, can be set to about 5 mm to 50 mm.

[0011] As the member of the holder 1, steel, cast iron, etc. may be used. In particular, when steel is used among these members, the toughness of the holder 1 is high.

[0012] As shown in FIG. 1, the holder 1 has a first side surface 11 extending from the first end 1a toward the second end 1b above in the Z-axis direction, and a second side surface 12 located opposite to the first side surface 11. Further, the holder 1 has a third side surface 13 located between the first side surface 11 and the second side surface 12, and a fourth side surface 14 located between the first side surface 11 and the second side surface 12 and opposite to the third side surface 13. The third side surface 13 is the front-right surface in FIG. 1, and the fourth side surface 14 is the back-left surface in FIG. 1. The holder 1 has a front end surface 20 located on the side of the first end 1a, and a rear end surface 21 located opposite to the front end surface 20.

[0013] The first side surface 11 may have a protruding step portion 18 at a position closer to the first end 1a than the second end 1b so that the tip portion 11a protrudes upward. In this case, the thickness of the tip portion 11a can be ensured, and the cutting load during cutting can be received. The tip portion 11a has a pocket 19 and is a portion for gripping the insert 2.

[0014] The front end surface 20 is not limited to the case of being perpendicular to the first central axis L1, and may be inclined from the direction perpendicular to the first central axis L1. Further, the front end surface 20 does not need to be formed by one plane. For example, the front end surface 20 may be formed by a plurality of planes, or may be formed by a curved surface. In the example shown in FIG. 1, in accordance with the shape of the rhombic plate-shaped insert 2, the front end surface 20 is inclined such that the side of the third side surface 13 is located in front in the Y-axis direction and the side of the fourth side surface 14 is located behind in the Y-axis direction.

[0015] The portion on the side of the second end 1b of the holder 1 may be supported by a tool rest 4 (see FIG. 7) described later when the cutting tool 100 is attached to the tool rest 4.

[0016] <Pocket> On the side of the first end 1a of the tip portion 11a, a pocket 19 to which the insert 2 can be attached may be provided. The pocket 19 may be a depression in which the insert 2 is attached. In the example shown in FIG. 1, the pocket 19 is open with respect to the tip surface 20 and the third side surface 13. The pocket 19 has a bottom surface 19a against which the installation surface, which is one surface in the thickness direction of the insert 2, abuts, and two restraint side surfaces 19b that are perpendicular to the bottom surface 19a and against which the side surface of the insert 2 abuts and is restrained. The bottom surface 19a may be parallel to the second side surface 12.

[0017] <Insert> The shape of the insert 2 is not limited to a specific configuration. For example, the shape of the insert 2 may be a rod shape, a polygonal plate shape, or a polygonal prism shape. In the present embodiment, the insert 2 has the shape of a rhombic plate as shown in FIG. 1. When the insert 2 has the shape of a rhombic plate, the shape of the bottom surface 19a of the pocket 19 may be rhombic according to the shape of the installation surface of the insert 2.

[0018] One corner on the side of the first end 1a on the upper surface of the insert 2 may be a cutting edge 2a. Specifically, the cutting edge 2a is located at the intersection of the upper surface of the insert 2 that is substantially parallel to the first side surface 11 and the side surface of the insert 2 that intersects this upper surface. The cutting edge 2a includes the end portion on the side of the first end 1a on the upper surface of the insert 2. A through hole may be provided in the central portion of the insert 2, the rhombic installation surface may be placed on the bottom surface 19a, and the insert 2 may be fixed to the pocket 19 by inserting a screw 3 through this through hole and screwing it to the bottom surface 19a.

[0019] Examples of the material of the insert 2 may include cemented carbide and cermet. Examples of the composition of the cemented carbide may include WC-Co, WC-TiC-Co, or WC-TiC-TaC-Co. Here, WC, TiC, and TaC may be hard particles, and Co may be a binder phase.

[0020] Alternatively, the cermet may be a sintered composite material obtained by compounding a metal with a ceramic component. As an example of the cermet, titanium compounds mainly composed of titanium carbide (TiC) or titanium nitride (TiN) can be mentioned. The material of the insert 2 is not limited to the above composition.

[0021] The surface of the insert 2 may be coated with a film formed by a chemical vapor deposition (CVD) method or a physical vapor deposition (PVD) method. Examples of the composition of the film include titanium carbide (TiC), titanium nitride (TiN), titanium carbonitride (TiCN), or alumina (Al2O3).

[0022] <The second side surface and the stepped portion> As shown in FIGS. 2 to 4, the second side surface 12 may have a first region 15, a second region 16, and a stepped portion 17. The first region 15 is, for example, a flat region located on the side of the first end 1a. The second region 16 is, for example, a flat region located closer to the second end 1b than the first region 15 and closer to the first side surface 11 than the first region 15. The stepped portion 17 connects the first region 15 and the second region 16, for example. As shown in FIG. 3, in the present embodiment, the stepped portion 17 is located on the side of the second end 1b with respect to the protruding stepped portion 18.

[0023] The stepped portion 17 is a portion for positioning the cutting tool 100 on the tool rest 4 and is locked to the tool rest 4. In the cutting tool 100 of the present disclosure, unlike the positioning structures of the cutting tools in Patent Documents 1 and 2, the positioning member is not a member separate from the holder of the cutting tool but is a part of the holder 1. Therefore, it is not necessary to consider the machining accuracy of the portion of the holder to which the positioning member is attached and the mounting accuracy when attaching the positioning member to the holder.

[0024] As shown in FIG. 6 which is a view taken along the line VI-VI of FIG. 5, the stepped portion 17 is curved convexly toward the second end 1b in a cross section parallel to the first region 15. As shown in FIGS. 5 and 6, the stepped portion 17 is curved convexly toward the second end 1b in the above-mentioned cross section and has a curved surface shape with a constant width in the Y-axis direction. When the stepped portion 17 is linear in the above-mentioned cross section, that is, when the stepped portion 17 is provided to extend straight in the X-axis direction in FIG. 6, during the machining of the stepped portion 17, the stepped portion 17 may extremely incline toward the first end 1a side or the second end 1b side due to errors.

[0025] In this case, it will be in point contact with the locking portion of the tool rest 4 (see FIG. 11). FIG. 11 is an enlarged side view showing a state where the right corner of the locking portion of the tool rest 4 abuts on the stepped portion 17 when the stepped portion 17 is formed to incline toward the first end 1a side due to machining errors when the stepped portion 17 is provided to extend straight in the Z-axis direction. Even if the holder 1 and the tool rest 4 are elastically deformed, in the situation where the stepped portion 17 is extremely inclined as described above, the contact area of the locking portions of the holder 1 and the tool rest 4 is limited and substantially remains in a state of point contact. In such a point contact, when a cutting load is applied by cutting, there is a possibility that the holder 1 may move because the tool rest 4 cannot receive the cutting load. As a result, the holder 1 cannot be positioned, and the machining accuracy of cutting deteriorates.

[0026] On the other hand, by adopting a configuration in which the stepped portion 17 is curved convexly toward the second end 1b, it is in point contact with the locking portion of the tool rest 4 in a curve and actually in surface contact due to elastic deformation, so that stable positioning can be easily performed (see FIG. 10). Even when machining errors occur in the stepped portion 17, since it is a curve, the errors are absorbed. And when a cutting load is applied, the load is absorbed, the positioning accuracy, in other words, the mounting accuracy to the tool rest 4 can be maintained, and the machining accuracy of cutting is good.

[0027] The stepped portion 17 may be arc-shaped in the above-mentioned cross section. In this case, the influence when machining errors occur in the stepped portion 17 can be further reduced.

[0028] When the second side surface 12 is viewed from the front, at least a part of the step portion 17 may be located in a region where the pocket 19 is extended toward the second end 1b. In this case, at least a part of the step portion 17 is located on the rear side of the pocket 19, and can absorb the cutting load during machining and maintain good positioning accuracy.

[0029] The step portion 17 may be in contact with the third side surface 13 and the fourth side surface 14. In this case, the step portion 17 is provided over the entire width of the second side surface 12, has high durability against the cutting load, and can maintain good positioning accuracy.

[0030] As shown in FIGS. 4 and 6, the step portion 17 has a tip portion 17a located closest to the second end 1b, and the length from the tip portion 17a to the third side surface 13 may be shorter than the length from the tip portion 17a to the fourth side surface 14. In this case, the wall thickness of the tip portion 11a having the pocket 19 can be ensured, and the durability against the cutting load is increased.

[0031] The tip portion 17a may be in contact with the third side surface 13. In this case, the step portion 17 is provided over a wide range of the second side surface 12 and has high durability against the cutting load.

[0032] As shown in FIG. 3, the second side surface 12 on which the step portion 17 is formed may be separated from the pocket 19. By forming the step portion 17 on the second side surface 12 separated from the pocket 19, the cutting load can be better received and the positioning accuracy is good, compared with forming the step portion 17 on the first side surface 11 or the third side surface 13 on which the pocket 19 is formed.

[0033] In the above-described cutting tool 100, the case where the step portion 17 is provided on the second side surface 12 has been described, but the present invention is not limited thereto. As will be described later, it may be provided on the first side surface 11 or the third side surface 13 that can be locked to the tool rest 4.

[0034] <Mounting structure to the tool rest> Hereinafter, FIG. 7 is a perspective view showing a state where a cutting tool 100 is supported by a tool post 4 in a non-limiting embodiment of the present disclosure. FIG. 8 is a plan view of the cutting tool 100 and the tool post 4 shown in FIG. 7. FIG. 9 is a side view of the cutting tool 100 and the tool post 4 shown in FIG. 8 and FIG. 7. FIG. 10 is an enlarged side view of a part of the front side portion of FIG. 9.

[0035] In each figure, the X-axis direction is the left-right direction, the Z-axis direction is the up-down direction, and the Y-axis direction is the front-back direction. In FIG. 7, the side where the insert 2 is located is the right side in the X-axis direction, the front side in the Y-axis direction, and the side where the fourth side surface 14 is located is the upper side in the Z-axis direction.

[0036] As shown in FIG. 7, the tool post 4 includes a base 41, a plurality of support portions 42, a screw hole 43, a clamping portion 44, and a set screw 45. The base 41 has a rectangular plate shape with a dimension in the X-axis direction longer than that in the Y-axis direction. On the base 41, a plurality of support portions 42 extending in the Y-axis direction are provided in a comb-like shape. The tool post with the plurality of support portions 42 provided in a comb-like shape as shown in FIG. 7 is generally called a comb-type tool post.

[0037] The support portion 42 has a right side surface 421, a left side surface 422, a front end surface 423, and a bottom surface 425. The bottom surface 425 is the bottom of the comb-like groove and faces upward. The right side surface 421 stands upright upward from the bottom surface 425. The left side surface 422 stands upright upward from the bottom surface 425 and then has a shape inclined obliquely upward to the right. The front end surface 423 is located on the front side between the right side surface 421 and the left side surface 422.

[0038] Two screw holes 43 are provided near the front of the support portion 42. The clamping portion 44 has an L-shape when viewed from the front. The clamping portion 44 is inserted between the cutting tool 100 and the left side surface 422 in a state where the vertical side portion of the L-shape abuts against the inclined portion of the left side surface 422, and the set screw 45 is inserted through the horizontal side portion of the L-shape, thereby being screwed into the screw hole 43 of the support portion 42.

[0039] The cutting tool 100 is placed between adjacent support portions 42 with the first side surface 11 facing right so that the tip portion 11a is positioned forward, and the right corner portion 424 of the front end surface 423 of the support portion 42 is locked to the step portion 17. As described above, since the step portion 17 has a convex curved shape toward the second end 1b in a cross-sectional view, as shown in FIG. 10, the step portion 17 can be in surface contact with the right corner portion 424 and can be positioned well. In this state, the clamping portion 44 is inserted between the first side surface 11 and the adjacent support portion 42, and the set screw 45 is screwed into the screw hole 43, whereby the cutting tool 100 is fixed to the tool rest 4. Since it is formed in a curved shape, even when a machining error occurs in the step portion 17, the right corner portion 424 can be in surface contact with the step portion 17. When a load is applied to the step portion 17 during cutting, the load is absorbed and the positioning accuracy is maintained.

[0040] FIG. 11 is an enlarged side view showing a state where the right corner portion 424 is in contact with the step portion 27 when the step portion is provided so as to extend straight in the Z-axis direction and the step portion 27 generated by a machining error is inclined toward the first end 1a. As shown in FIG. 11, the right corner portion 424 will be in point contact with the step portion 27, is easy to move, and positioning is difficult.

[0041] A plurality of cutting tools 100 are supported between the support portions 42, 42. According to the cutting tool 100 of the present disclosure, the positioning of the cutting tool 100 in the Y-axis direction can be performed well, and the protrusion amount of the tip portion 11a from the base 41 can be made uniform among the cutting tools 100. Therefore, the same workpiece can be accurately machined in order by a plurality of cutting tools 100. Even when a cutting load is applied during cutting, it can be absorbed by the step portion 17, and the positioning accuracy can be maintained.

[0042] As shown in an example in FIGS. 4 and 5, the stepped portion 17 may have a groove shape that is recessed toward the first side surface 11. At this time, the stepped portion 17 may have a bottom surface 17b that is closest to the first side surface 11. It can also be said that the bottom surface 17b is located closest to the first side surface 11 in the stepped portion 17. At this time, as shown in an example in FIG. 5, the bottom surface 17b may be located closer to the first side surface 11 than the second region 16.

[0043] A wall surface that rises from the bottom surface 17b of the stepped portion 17 and faces the side of the bottom surface 17b is defined as the wall surface 17c shown in FIG. 5. In this case, in the stepped portion 17, the boundary between the bottom surface 17b and the wall surface 17c is likely to have relatively low strength. When the cutting tool 100 is attached to the tool post 4, if the right-angled portion 424 abuts against this boundary, there is a risk of cracks occurring at the above-mentioned boundary. However, when the stepped portion 17 has the above configuration, it is difficult for the right-angled portion 424 to abut against the above-mentioned boundary. Therefore, a decrease in the strength of the holder 1 can be avoided.

[0044] When the stepped portion 17 has a bottom surface 17b, the height h1 from the bottom surface 17b to the second region 16 may be smaller than the height h2 from the second region 16 to the first region 15. Here, "height" means the width in the vertical direction of the Z-axis. When the height h1 is relatively small, it is possible to avoid an excessive reduction in the wall thickness of the holder 1 between the bottom surface 17b and the first side surface 11. Also, when the height h2 is relatively large, the positioning accuracy of the holder 1 to the tool post 4 by the stepped portion 17 can be ensured to be high.

[0045] <Method for manufacturing a machined product> Next, a method for manufacturing a machined product according to a non-limiting aspect of the present disclosure will be described with reference to the drawings.

[0046] The machined product 101 is produced by machining the workpiece 103. The method for manufacturing the machined product 101 in the embodiment includes the following steps. That is, (1) A step of rotating the workpiece 103, (2) a step of bringing the cutting tool 100 represented by the above embodiment into contact with the rotating workpiece 103; (3) a step of separating the cutting tool 100 from the workpiece 103; comprises.

[0047] More specifically, first, as shown in FIG. 12, the workpiece 103 is rotated around the second central axis L2, and the tool post 4 supporting the cutting tool 100 is brought closer to the workpiece 103 relatively. Next, as shown in FIG. 13, at least a part of the cutting edge 2a of the cutting tool 100 is brought into contact with the workpiece 103 to machine the workpiece 103. Then, as shown in FIG. 14, the cutting tool 100 is relatively moved away from the workpiece 103 or the machined product 101.

[0048] As shown in FIG. 12, with the second central axis L2 fixed and the workpiece 103 rotated, the cutting tool 100 is moved forward in the Y-axis direction to bring the cutting tool 100 closer to the workpiece 103.

[0049] As shown in FIG. 13, with at least a part of the portion used as the cutting edge 2a of the insert 2 in contact with the rotating workpiece 103, the cutting tool 100 is moved downward in the Z-axis direction and forward in the Y-axis direction to machine the workpiece 103.

[0050] As shown in FIG. 14, with the workpiece 103 rotated, the cutting tool 100 is moved backward in the Y-axis direction to move the cutting tool 100 away from the workpiece 103.

[0051] In each step, the cutting tool 100 is moved to bring the cutting tool 100 into contact with the workpiece 103 or to separate the cutting tool 100 from the workpiece 103, but it is not limited to this case.

[0052] For example, in the step of (1), the workpiece 103 may be brought closer to the cutting tool 100. In the step of (3), the workpiece 103 may be moved away from the cutting tool 100. When continuing the cutting process, the step of maintaining the workpiece 103 in a rotated state and bringing at least a part of the cutting edge 2a of the insert 2 into contact with different portions of the workpiece 103 may be repeated. Subsequently, the workpiece 103 may be continuously machined by another cutting tool 100 supported by the tool post 4.

[0053] Typical examples of the material of the workpiece 103 may include hardened steel, carbon steel, alloy steel, stainless steel, cast iron, or non-ferrous metal, etc.

[0054] According to the method for manufacturing a machined product of the present disclosure, since the cutting tool 100 of the present disclosure is well positioned on the tool post 4 by the step portion 17 in the holder 1, machining can be performed with high precision. And when performing cutting with a plurality of cutting tools 100 supported by the tool post 4, the protruding amount from the base 41 can be made uniform, so that machining can be performed in order with high precision.

Explanation of reference numerals

[0055] 1... Holder 1a... First end (tip) 1b... Second end (rear end) 11... First side surface 12... Second side surface 13... Third side surface 14... Fourth side surface 15... First region 16... Second region 17... Step portion 17b... Bottom surface 17c... Wall surface 18... Protruding step portion 19... Pocket 20... Front end surface 21... Rear end surface 2... Cutting insert (insert) 2a... Cutting edge 3... Screw 4... Tool post 41 ··· Base 42 ··· Support part 43 ··· Screw hole 44 ··· Clamping part 45 ··· Set screw 100 ··· Cutting tool 101 ··· Machined part 103 ··· Workpiece L1 ··· First central axis L2 ··· Second central axis

Claims

1. It is a quadrangular prism shape extending from a first end to a second end, a pocket that is located on the side of the first end and to which a cutting insert can be attached, a first side surface extending from the first end toward the second end, and a second side surface located opposite to the first side surface, and has, the second side surface, a flat first region located on the side of the first end, a flat second region that is closer to the second end than the first region and closer to the first side surface than the first region, and a step portion connecting the first region and the second region, and has, the step portion forms a convex curved shape toward the second end in a cross section parallel to the first region, the holder according to the description, wherein when the second side surface is viewed from the front, at least a part of the step portion is located in a region where the pocket is extended toward the second end.

2. It is a quadrangular prism shape extending from a first end to a second end, a pocket that is located on the side of the first end and to which a cutting insert can be attached, a first side surface extending from the first end toward the second end, and a second side surface located opposite to the first side surface, and has, the second side surface, a flat first region located on the side of the first end, a flat second region that is closer to the second end than the first region and closer to the first side surface than the first region, and a step portion connecting the first region and the second region, and has, the step portion forms a convex curved shape toward the second end in a cross section parallel to the first region, a third side surface located between the first side surface and the second side surface, and a fourth side surface located between the first side surface and the second side surface and opposite to the third side surface, and further has, the pocket is open to the first side surface and the third side surface, the holder, wherein the step portion is in contact with the third side surface and the fourth side surface.

3. In a cross section parallel to the first region, the step portion has a tip portion that is located closest to the second end, the holder according to claim 2, wherein the length from the tip portion to the third side surface is shorter than the length from the tip portion to the fourth side surface.

4. The holder according to claim 3, wherein the tip portion is in contact with the third side surface.

5. It is a quadrangular prism shape extending from a first end to a second end, a pocket that is located on the side of the first end and to which a cutting insert can be attached, a first side surface extending from the first end toward the second end, It has a second side surface located opposite to the first side surface, The second side surface is A flat first region located on the side of the first end, A flat second region located closer to the second end than the first region and closer to the first side surface than the first region, It has a step portion connecting the first region and the second region, In a cross-section parallel to the first region, the step portion has a curved shape convex toward the second end, The step portion has a groove shape recessed toward the first side surface and has a bottom surface closest to the first side surface, The bottom surface is located closer to the first side surface than the second region, a holder.

6. The holder according to claim 5, wherein the height from the bottom surface to the second region is smaller than the height from the second region to the first region.

7. The holder according to any one of claims 1 to 6, wherein the step portion has an arc shape in a cross-section parallel to the first region.

8. The holder according to any one of claims 1 to 6, wherein the second side surface is away from the pocket.

9. A cutting tool comprising the holder according to any one of claims 1 to 6 and A cutting insert located in the pocket.

10. A step of rotating the workpiece, A step of bringing the cutting tool according to claim 9 into contact with the rotating workpiece, A step of separating the cutting tool from the workpiece, a method for manufacturing a machined product having these steps.

Images