Drill and method for manufacturing machined product

Abstract

A drill bit based on an unrestricted aspect of the present disclosure has a main body extending from a first end to a second end along a rotation axis and capable of rotating around the rotation axis. The main body has a first blade, a second blade extending from the first blade toward the periphery, a grinding surface arranged along the first blade, a groove extending from the second blade and the grinding surface toward the second end, and an outer peripheral surface. The outer peripheral surface has a first land surface arranged along the groove behind the rotation direction of the rotation axis, a gap surface arranged along the first land surface, and a second land surface arranged along the gap surface. When viewed toward the first end, an imaginary straight line connecting the rotation axis and the end of the outer peripheral side of the first blade is a first straight line, and an imaginary straight line passing through the center of the first straight line and orthogonal to the first straight line is a second straight line, and the second straight line intersects with the second land surface.

Description

[0001] Cross-reference to related applications

[0002] This application claims the benefit of priority based on Japanese Patent Application No. 2019-223406 filed on December 11, 2019, and the disclosure of the prior application is incorporated herein by reference in its entirety. Technical Field

[0003] The present disclosure generally relates to a drill used in hole drilling of a workpiece and a method for manufacturing a cut product. As the drill, there can be cited a monolithic drill and a front-end replaceable drill. Background Art

[0004] As a drill used for drilling a metal or other workpiece, there is known a drill described in Japanese Patent Publication No. 2011-020256 (Patent Document 1). The drill described in Patent Document 1 has first to third land portions on the outer peripheral surface. When the drill has multiple land surfaces, the straightness of the drill is improved.

[0005] In recent years, there has been a demand for drill bits with higher straightness. Summary of the invention

[0006] A drill bit according to an unrestricted aspect of the present disclosure has a main body extending from a first end to a second end along a rotation axis and capable of rotating around the rotation axis. The main body has a first blade located on the first end side and extending from the rotation axis toward the periphery, a second blade extending from the first blade toward the periphery, a grinding surface arranged along the first blade, a groove extending spirally around the rotation axis from the second blade and the grinding surface toward the second end, and an outer peripheral surface. The outer peripheral surface has a first land surface arranged along the groove behind the rotation direction of the rotation axis, a clearance surface arranged along the first land surface behind the rotation direction, and a second land surface arranged along the clearance surface behind the rotation direction. In addition, when viewed toward the first end, an imaginary straight line connecting the rotation axis and the end of the outer peripheral side of the first blade is a first straight line, an imaginary straight line passing through the center of the first straight line and orthogonal to the first straight line is a second straight line, and the second straight line intersects with the second land surface. BRIEF DESCRIPTION OF THE DRAWINGS

[0007] Figure 1 It is a perspective view showing a drill bit according to a non-limiting embodiment of the present disclosure.

[0008] Figure 2 Looking toward the first end Figure 1 Top view of the drill bit shown.

[0009] Figure 3 Looking toward the first end Figure 1 Top view of the drill bit shown.

[0010] Figure 4 Observed from B1 direction Figure 2 The drill bit is shown in a side view.

[0011] Figure 5 Observed from B2 direction Figure 2 The drill bit is shown in side view.

[0012] Figure 6 Observed from B3 direction Figure 2 The drill bit is shown in side view.

[0013] Figure 7 Yes Figure 1 An enlarged view of area A1 is shown.

[0014] Figure 8 yes Figure 6 A cross-sectional view of section VIII in the drill bit is shown.

[0015] Fig. 9 is a top view of a drill bit of an unrestricted embodiment of the present disclosure viewed toward the first end, and is Figure 3 Quite a picture.

[0016] Fig.10 This is a schematic diagram showing one step in a method for producing a machined product according to a non-limited embodiment of the present disclosure.

[0017] Fig.11 This is a schematic diagram showing one step in a method for producing a machined product according to a non-limited embodiment of the present disclosure.

[0018] Fig.12 This is a schematic diagram showing one step in a method for producing a machined product according to a non-limited embodiment of the present disclosure. DETAILED DESCRIPTION

[0019] <Drill>

[0020] Hereinafter, the drill bit of the non-limited multiple embodiments of the present disclosure will be described in detail using the accompanying drawings. In each of the drawings referred to below, for the sake of convenience, only the main components required to explain each embodiment are simplified. Therefore, the drill bit may have any constituent components not shown in the drawings referred to. In addition, the dimensions of the components in the drawings do not faithfully represent the dimensions of the actual constituent components and the dimensional ratios of the components.

[0021] exist Figures 1 to 8In the figure, an integral drill bit is shown as a non-limited example of the drill bit 1. It should be noted that the drill bit 1 is not limited to an integral drill bit, and may be, for example, a front-end replaceable drill bit.

[0022] like Figure 1 As shown in the non-limiting example, the drill bit 1 may have a body 3. The body 3 may extend from a first end 3a to a second end 3b along the rotation axis O1. More specifically, the body 3 may be in the shape of a rod extending from the first end 3a to the second end 3b along the rotation axis O1. Usually, the first end 3a is referred to as the "front end" and the second end 3b is referred to as the "rear end". In addition, the body 3 may be able to rotate around the rotation axis O1. It should be noted that Figure 1 The arrow Y1 in FIG. 1 indicates the rotation direction of the rotation axis O1 .

[0023] The body 3 may include a handle 5 and a cutting portion 7. The handle 5 may be a portion that can be gripped by a rotating spindle of a machine tool. The handle 5 may be designed according to the shape of the spindle in the machine tool.

[0024] The cutting portion 7 is located on the first end 3a side with respect to the shank portion 5. The cutting portion 7 is a portion that can come into contact with a workpiece and can play a major role in cutting processing (for example, drilling processing) of the workpiece.

[0025] The outer diameter D of the cutting portion 7 is not limited to a specific value. For example, the maximum value of the outer diameter D can be set to 4 to 50 mm. In addition, the length L of the cutting portion 7 along the rotation axis O1 can be set to L=1.5D to 12D.

[0026] like Figure 2 As shown in the non-limited example, the main body 3 may have a first blade 9, a second blade 11, a grinding surface 13, a groove 15, and an outer peripheral surface 17. The first blade 9 may be located on the first end 3a side. In addition, the first blade 9 may extend from the rotation axis O1 toward the periphery. The second blade 11 may extend from the first blade 9 toward the periphery. The grinding surface 13 may be arranged along the first blade 9. The groove 15 may extend spirally around the rotation axis O1 from the second blade 11 and the grinding surface 13 toward the second end 3b. It should be noted that the first blade 9, the second blade 11, the grinding surface 13, the groove 15, and the outer peripheral surface 17 may be located in the cutting portion 7.

[0027] The first blade 9 can be used to cut the workpiece during cutting. The number of the first blade 9 can be one or more. In the case where the number of the first blade 9 is more than one, the number can be 2 to 5. The same is true for the second blade 11. It should be noted that Figure 1 The drill 1 in the illustrated, non-limiting example is a so-called double-edged drill.

[0028] When there are multiple first blades 9, the multiple first blades 9 may be located at positions that are rotationally symmetrical with respect to the rotation axis O1 when viewed toward the first end 3a. Figure 2 As shown in the non-limiting example, when the number of first blades 9 is two, the two first blades 9 can be located at positions that are rotationally symmetrical by 180 degrees with respect to the rotation axis O1 when viewed toward the first end 3a. In this case, the straightness of the drill bit 1 when cutting the workpiece is high. These points are also the same for the second blade 11.

[0029] The first blade 9 may have a chisel edge 19. The chisel edge 19 may be located closest to the rotation axis O1 in the first blade 9. Alternatively, the chisel edge 19 may be located at a position intersecting the rotation axis O1. When viewed toward the first end 3a, the chisel edge 19 may be a straight line or a curved line. Figure 2 The chisel edge 19 in the illustrated, non-limiting example is linear when viewed toward the first end 3 a .

[0030] The first blade 9 may have a grinding blade 21. The grinding blade 21 may be located closer to the outer peripheral surface 17 than the chisel blade 19. In addition, the length of the grinding blade 21 may be longer than the length of the chisel blade 19. It should be noted that the chisel blade 19 and the grinding blade 21 may be connected to each other, and other blades may be arranged between the two. Figure 2 In the illustrated, non-limiting example, the chisel edge 19 and the dressing edge 21 are connected to each other.

[0031] When viewed toward the first end 3a, the grinding edge 21 may be in a straight line shape or in a curved line shape. Figure 2 As shown in the non-limiting example, the dressing edge 21 may have a shape that is a combination of a straight line shape and a curved line shape when viewed toward the first end 3 a .

[0032] The second edge 11 can be used to cut the workpiece during cutting. The second edge 11 is also called a main cutting edge. The length of the second edge 11 can be longer than the length of the first edge 9. The second edge 11 is in a straight line shape when viewed toward the first end 3a, and can also be in a curved shape. Figure 2 As shown in the non-limiting example, the second edge 11 may have a concave curve shape when viewed toward the first end 3a.

[0033] It should be noted that the first blade 9 and the second blade 11 may be connected to each other, or other blades may be arranged between them. Figure 2 In the non-limiting example shown, the first cutting edge 9 and the second cutting edge 11 are connected to each other.

[0034] The ground surface 13 can function as a surface for allowing the chips generated by the first blade 9 to flow. In addition, the ground surface 13 can also be used to improve the strength of the cutting edge and improve the cutting performance into the workpiece.

[0035] The groove 15 can be mainly used to discharge the chips generated by the second blade 11 to the outside. The number of the groove 15 may be one or more. The number of the groove 15 may be the same as the number of the second blade 11.

[0036] The groove 15 may be connected to the second blade 11. In this case, the cutting property of the workpiece is high. In addition, a rake face connecting the groove 15 and the second blade 11 may be arranged between the groove 15 and the second blade 11. In this case, the discharge direction of the chips generated by the second blade 11 is easy to stabilize. From the viewpoint of smoothly discharging the chips to the outside, the groove 15 may be a concave curve shape in a cross section orthogonal to the rotation axis O1.

[0037] The depth of the groove 15 is not limited to a specific value. For example, the depth of the groove 15 can be set to 10% to 40% relative to the outer diameter of the body 3 (cutting portion 7). The depth of the groove 15 can be a value obtained by subtracting the distance between the bottom of the groove 15 and the rotation axis O1 from the radius of the body 3 (cutting portion 7) in a cross section perpendicular to the rotation axis O1. The bottom can be the portion of the groove 15 closest to the rotation axis O1.

[0038] The outer peripheral surface 17 may have a first land surface 23, a clearance surface 25, and a second land surface 27. The first land surface 23 may be arranged along the groove 15 behind the rotation direction Y1 of the rotation axis O1. The clearance surface 25 may be arranged along the first land surface 23 behind the rotation direction Y1. The second land surface 27 may be arranged along the clearance surface 25 behind the rotation direction Y1.

[0039] The first land surface 23 and the second land surface 27 can be used to make sliding contact with the inner wall surface of the hole formed by the first blade 9 and the second blade 11 to stabilize the operability of the drill bit 1. Figure 8 As shown in the non-limiting example, in the cross section perpendicular to the rotation axis O1 , the first land surface 23 and the second land surface 27 may be arc-shaped portions corresponding to the outer circumference of the body 3 .

[0040] The clearance surface 25 can be used to reduce friction with a workpiece during cutting. The clearance surface 25 may be recessed relative to the first land surface 23 and the second land surface 27 .

[0041] It should be noted that the first land surface 23, the clearance surface 25 and the second land surface 27 may be connected to each other, and other surfaces may be arranged between adjacent surfaces. Figure 2 In the illustrated non-limiting example, the first land surface 23 , the clearance surface 25 , and the second land surface 27 are connected to one another.

[0042] Here, the drill bit 1 may have the following structure when viewed toward the first end 3a. Figure 3 As shown in the non-limited example, the imaginary straight line connecting the rotation axis O1 and the end 9a on the outer peripheral side of the first blade 9 can be the first straight line L1. In addition, the imaginary straight line passing through the center (midpoint) L1a of the first straight line L1 and orthogonal to the first straight line L1 can be the second straight line L2. And the second straight line L2 can intersect with the second land surface 27. It should be noted that orthogonality only needs to be substantially orthogonal, and does not need to be strictly orthogonal. Orthogonality can include a range of 90 degrees ± 2 degrees.

[0043] In the above case, since the first land surface 23 and the second land surface 27 are in contact with the machined wall surface, the first land surface 23 and the second land surface 27 can easily serve as a guide during drilling. Therefore, the straightness of the drill 1 is high.

[0044] The width W1 of the first land surface 23 in the rotation direction Y1 and the width W2 of the second land surface 27 in the rotation direction Y1 may be the same or different. The second land surface 27 is more likely to be located near the second edge 11 in the direction of application of the main component of the cutting load applied to the second edge 11 than the first land surface 23. Figure 3 As in the illustrated non-limiting example, when the width W2 is larger than the width W1 , the cutting load applied to the second cutting edge 11 can be easily and stably received on the second land surface 27 .

[0045] The width W3 of the gap surface 25 in the rotation direction Y1 may be the same as the width W1 and the width W2, or may be different. Figure 3 As in the non-limiting example shown, when the width W3 is larger than the width W1 and the width W2, the contact area between the first land surface 23 and the second land surface 27 and the wall surface of the machined hole is small, so the cutting resistance is easily reduced.

[0046] It should be noted that the width W1, the width W2, and the width W3 are not limited to specific values. For example, in a cross section perpendicular to the rotation axis O1, the width W1 can be set to 0.15 to 4% relative to the total length of the outer circumference of the body 3 (cutting portion 7). In addition, the width W2 can be set to 14 to 23%. The width W3 can be set to 0.3 to 12%.

[0047] like Figure 3As shown in the non-limiting example, when viewed toward the first end 3a, the second straight line L2 may pass through the center (center) 27a of the second land surface 27. In this case, the cutting load applied to the first blade 9 is easily stably borne by the second land surface 27. Therefore, vibration of the drill bit 1 caused by the first blade 9 cutting into the workpiece is unlikely to occur.

[0048] like Figure 2 As shown in the non-limiting example, the main body 3 may further have a No. 2 back cutting edge 29, a No. 3 back cutting edge 31 and a No. 4 back cutting edge 33. The No. 2 back cutting edge 29 may be arranged along the second edge 11. In addition, the No. 2 back cutting edge 29 may be flat. The No. 3 back cutting edge 31 may be arranged along the No. 2 back cutting edge 29 behind the rotation direction Y1, and be inclined relative to the No. 2 back cutting edge 29. In addition, the No. 3 back cutting edge 31 may be flat. The No. 4 back cutting edge 33 may be arranged along the No. 3 back cutting edge 31 behind the rotation direction Y1, and be inclined relative to the No. 3 back cutting edge 31. In addition, the No. 4 back cutting edge 33 may be flat.

[0049] The second land surface 27 can be connected to the third flank face 31 and separated from the second flank face 29 and the fourth flank face 33. When the second land surface 27 is separated from the second flank face 29, the main component of the cutting load applied to the first edge 9 and the second edge 11 is easily borne by the second land surface 27. In addition, when the second land surface 27 is separated from the fourth flank face 33, the second land surface 27 can be located near the first end 3a, compared with the case where the second land surface 27 is connected to the third flank face 31. Therefore, during the hole drilling process, the second land surface 27 can contact the workpiece near the first end 3a, and the straight-feed stability of the drill 1 is easily improved.

[0050] It should be noted that the inclination angles of the third flank 31 and the fourth flank 33 are not limited to specific values. For example, the inclination angle of the third flank 31 can be set to 15° to 35°. In addition, the inclination angle of the fourth flank 33 can be set to 30° to 55°.

[0051] The second flank face 29, the third flank face 31 and the fourth flank face 33 may be connected to each other, and other surfaces may be arranged between adjacent flank faces. Figure 2 In the non-limiting example shown, the second relief surface 29 , the third relief surface 31 , and the fourth relief surface 33 are connected to each other.

[0052] like Figure 7As shown in the non-limiting example, the clearance surface 25 may have a plurality of convex strips (convex portions) 35 extending along the first land surface 23. In this case, the surface area of ​​the clearance surface 25 is large, and the heat dissipation is easily improved. Therefore, the heat generated during cutting is easily dissipated to the outside, and it is easy to avoid the drill 1 from becoming excessively high temperature.

[0053] When viewed toward the first end 3a, the width W2 of the second land surface 27 in the rotation direction Y1 may be the same as or different from the length of the first blade 9. When the width W2 is the same as the length of the first blade 9, the cutting load generated by the first blade 9 is easily and stably borne by the second land surface 27. Therefore, vibration of the drill bit 1 is not likely to occur. It should be noted that the width W2 being the same as the length of the first blade 9 is not limited to the values ​​of the two being strictly the same. For example, there may be a difference of 10% between the values ​​of the two.

[0054] As the material of the main body 3, for example, cemented carbide and cermet can be cited. As the composition of the cemented carbide, for example, WC-Co, WC-TiC-Co and WC-TiC-TaC-Co can be cited. Here, WC, TiC and TaC can be hard particles, and Co can be a binding phase.

[0055] In addition, the metal ceramic can be a sintered composite material formed by compounding metal and ceramic components. Specifically, as the metal ceramic, a titanium compound with titanium carbide (TiC) or titanium nitride (TiN) as the main component can be cited. Among them, the above-mentioned materials are not limited to examples, and the main body 3 is not limited to these materials.

[0056] The surface of the main body 3 can be coated with a coating using a chemical vapor deposition (CVD) method or a physical vapor deposition (PVD) method. Examples of the composition of the coating include titanium carbide (TiC), titanium nitride (TiN), titanium carbonitride (TiCN), and aluminum oxide (Al2O3).

[0057] Next, use Fig. 9 A drill bit 1a according to one embodiment of the present invention will be described. The drill bit 1a will be described below mainly with respect to the differences from the drill bit 1, and detailed descriptions of the drill bit 1a having the same structure as the drill bit 1 may be omitted.

[0058] In the drill bit 1a, as Fig. 9As shown in the non-limiting example, when viewed toward the first end 3a, the width W21 of the portion of the second land surface 27 located behind the second straight line L2 in the rotation direction Y1 may be larger than the width W22 of the portion of the second land surface 27 located in front of the second straight line L2 in the rotation direction Y1. In this case, when the drill bit 1a is viewed toward the first end 3a, it is easy to set the portion of the second land surface 27 that forms a smaller angle with the second edge 11. Therefore, the cutting load applied not only to the first edge 9 but also to the second edge 11 can be stably borne by the second land surface 27. Therefore, the straight-feed stability during machining is easily improved.

[0059] <Method for Manufacturing Cutting Work>

[0060] Next, refer to Figure 10 to Figure 12 A method for manufacturing the machined product 101 according to an embodiment not limited to this will be described in detail. Figure 10 to Figure 12 In the non-limiting example shown, the drill 1 is used, but the present invention is not limited to this embodiment. For example, the drill 1a may be used.

[0061] The machined product 101 can be manufactured by cutting a workpiece 103. The method for manufacturing the machined product 101 may include the following steps (1) to (4).

[0062] (1) A step of placing the drill bit 1 above the prepared workpiece 103 (see Fig.10 ).

[0063] (2) A step of rotating the drill 1 in the direction of arrow Y1 about the rotation axis O1 and approaching the workpiece 103 in the direction of arrow Y2 (see Fig.10 ).

[0064] The steps (1) and (2) can be performed, for example, as follows: the workpiece 103 is fixed on a table of a machine tool on which the drill bit 1 is mounted, and the drill bit 1 is rotated to approach the workpiece 103. It should be noted that in the step (2), the workpiece 103 and the drill bit 1 only need to be relatively close to each other, and for example, the workpiece 103 can be brought close to the drill bit 1.

[0065] (3) A step of making the drill bit 1 closer to the workpiece 103 and bringing the rotating drill bit 1 into contact with a desired position on the surface of the workpiece 103, thereby forming a processed hole 105 in the workpiece 103 (see Fig.11 ).

[0066] In the step (3), cutting can be performed in such a manner that at least a portion of the cutting portion 7 in the body 3 is located in the machined hole 105. The shank portion 5 in the body 3 can be set to be located outside the machined hole 105. In addition, from the viewpoint of obtaining a good finished surface, a portion of the second end 3b side of the cutting portion 7 can be set to be located outside the machined hole 105. The above portion can be made to function as a land area for chip discharge, and excellent chip discharge performance can be achieved through this area.

[0067] (4) Step of separating the drill bit 1 from the workpiece 103 in the Y3 direction (see Fig.12 ).

[0068] In the step (4), similarly to the step (2) described above, the workpiece 103 and the drill bit 1 may be relatively separated. For example, the workpiece 103 may be separated from the drill bit 1.

[0069] Specifically, in the method for manufacturing the machined product 101 of the non-limited embodiment, when the drill 1 is used, the drill 1 has high straightness, so the machined product 101 having the machined hole 105 with high precision can be obtained.

[0070] It should be noted that when the cutting process of the cut workpiece 103 as shown above is performed multiple times, for example, when multiple processing holes 105 are formed on one cut workpiece 103, the process of making the first edge 9 and the second edge 11 of the drill bit 1 contact different positions of the cut workpiece 103 can be repeatedly performed while keeping the drill bit 1 in a rotating state.

[0071] Examples of the material of the workpiece 103 include aluminum, carbon steel, alloy steel, stainless steel, cast iron, and non-ferrous metals.

[0072] Description of reference numerals:

[0073] 1.1a···Drill bit

[0074] 3. Main Body

[0075] 3a··First end (front end)

[0076] 3b··Second end (rear end)

[0077] 5. Handle

[0078] 7···Cutting part

[0079] 9···The First Blade

[0080] 9a··End

[0081] 11···The Second Blade

[0082] 13···Grinding surface

[0083] 15···Slot

[0084] 17···Outer Surface

[0085] 19···Chisel blade

[0086] 21···Sharpening blade

[0087] 23···First land surface

[0088] 25···Gap surface

[0089] 27···Second land surface

[0090] 27a··Center

[0091] 29···No. 2 back face

[0092] 31···No. 3 back face

[0093] 33···No. 4 back face

[0094] 35···Protruding part (convex part)

[0095] 101···Machining products

[0096] 103···Workpiece

[0097] 105···Processing hole

[0098] O1···Rotation axis

[0099] Y1···Rotation direction

[0100] L1···First straight line

[0101] L1a··Center (midpoint)

[0102] L2···Second straight line.

Claims

1. A drill bit, wherein: The drill bit has a main body, which extends from a first end to a second end along a rotation axis and is rotatable about the rotation axis. The subject has: a first blade, which is located on the first end side and extends from the rotation axis toward the outer periphery; a second edge extending from the first edge toward the periphery; a grinding surface disposed along the first edge; a groove extending helically around the rotation axis from the second edge and the grinding surface toward the second end; as well as The outer surface, The outer peripheral surface has: a first land surface arranged along the groove behind the rotation direction of the rotation axis; a clearance surface arranged along the first land surface at the rear of the rotation direction; as well as a second land surface arranged behind the rotation direction along the gap surface, The clearance surface recessed relative to the first land surface and the second land surface has a plurality of convex strips extending along the first land surface. When viewed towards the first end, A virtual straight line connecting the rotation axis and the end portion on the outer peripheral side of the first blade is a first straight line. An imaginary straight line passing through the center of the first straight line and being orthogonal to the first straight line is a second straight line. The second straight line intersects the second land surface, The width of the second land surface in the rotation direction is the same as the length of the first edge.

2. The drill bit according to claim 1, wherein: The width of the second land surface in the rotation direction is wider than the width of the first land surface in the rotation direction.

3. The drill bit according to claim 1 or 2, wherein: The second straight line passes through a center of the second land surface when viewed toward the first end.

4. The drill bit according to claim 1 or 2, wherein: When viewed toward the first end, a portion of the second land surface located behind the second straight line in the rotation direction has a greater width than a portion of the second land surface located in front of the second straight line in the rotation direction.

5. The drill bit according to claim 1 or 2, wherein: The subject also has: a flat second relief surface disposed along the second cutting edge; A third flank face, which is arranged behind the second flank face in the rotation direction and is inclined relative to the second flank face; as well as a fourth clearance face, which is arranged behind the third clearance face in the rotation direction and is inclined relative to the third clearance face, The second land surface is connected to the third relief surface and is separated from the second relief surface and the fourth relief surface.

6. A method for manufacturing a machined product, wherein: The method for manufacturing a machined product comprises the following steps: Rotating the drill bit according to any one of claims 1 to 5; bringing the rotating drill bit into contact with a workpiece; and The drill bit is separated from the workpiece.

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